Performance and Power Factor Improvement of Indirect Vector Controlled Cage Induction Generator in Wind Power Application

Transcription

1 Pefomance and Powe Facto Impovement of Indiect Vecto Contolled Cage Induction Geneato in Wind Powe Application DEPARTMENT OF EECTRICA ENGINEERING NATIONA INSTITUTE OF TECHNOOGY, ROURKEA

2 Pefomance and Powe Facto Impovement of Indiect Vecto Contolled Cage Induction Geneato in Wind Powe Application A Thei Submitted in Patial Fulfillment of the Requiement fo the Degee of Mate of Technology (Reeach) in Electical Engineeing By Swagat pati Roll No: 68EE14 Unde the Supeviion of D. K.B.Mohanty (Aociate Pofeo) Depatment of Electical Engineeing National Intitute of Technology Roukela July 211

3 ABSTRACT Wind enegy i one of the mot impotant and pomiing ouce of enewable enegy all ove the wold, mainly becaue it i conideed to be nonpolluting and economically viable. At the ame time thee ha been a apid development of elated wind enegy technology. The contol and etimation of wind enegy conveion ytem contitute a vat ubject and ae moe complex than thoe of dc dive. Induction geneato with cage type oto have been ued extenively in wind powe geneation ytem fo the vaiable peed application in a wide powe ange. Geneally, vaiable peed wind enegy conveion ytem with Induction geneato equie both wide opeating ange of peed and fat toque epone, egadle of any ditubance and uncetaintie (tubine toque vaiation, paamete vaiation and un-modeled dynamic). Thi lead to moe advanced contol method to meet the eal demand. The ecent advance in the aea of field-oiented contol along with the apid development and cot eduction of powe electonic device and micopoceo have made vaiable peed wind enegy conveion ytem an economical altenative fo wind powe application. The complexity of wind enegy conveion ytem inceae ubtantially if high pefomance ae demanded. The main eaon fo thi complexity ae the need of vaiable fequency, hamonically optimum convete powe upplie, the complex dynamic of ac machine, machine paamete vaiation etc. Vaiou contol technique have been developed in the ecent day fo the contol of cage induction geneato. In thi wok a hybid contolle i developed fo pefomance impovement of a cage induction geneato ued fo wind powe application. The wind powe geneation ytem employ an indiect vecto contolled cage induction machine a the geneato. The induction geneato ytem i evaluated epaately with conventional PI-contolle, fuzzy contolle, elf tuned fuzzy contolle and hybid contolle and the pefomance ae compaed fo each cae. Powe facto of the oveall ytem i impoved though contol of gid ide convete. Contol cicuit fo PWM convete invete ytem ae alo fabicated and teted.

4 National Intitute of Technology Roukela CERTIFICATE Thi i to cetify that the thei entitled Pefomance and Powe Facto Impovement of Indiect Vecto Contolled Cage Induction Geneato in Wind Powe Application ubmitted by M. Swagat Pati, in patial fulfillment of the equiement fo the awad of Mate of Technology (Reeach) in Electical Engineeing, at National Intitute of Technology, Roukela (Deemed Univeity) i an authentic wok caied out by him unde my upeviion and guidance. To the bet of my knowledge, the matte peented in the thei ha not been ubmitted to any othe Univeity/Intitute fo the awad of any Degee o Diploma. Date: Place: NIT Roukela D. K.B.Mohanty (Aociate Pofeo) Depatment of Electical Engineeing National Intitute of Technology Roukela kbmohanty@nitkl.ac.in

5 ACKNOWEDGEMENT I have been vey fotunate in having D. K.B.Mohanty, Aociate Pofeo, Depatment of Electical Engineeing, National Intitute of Technology, Roukela a my thei upevio. He inpied me to develop inteet in Wind Enegy Sytem, taught me eence and pinciple of eeach and guided me though the completion of thi thei wok. Woking with Pof. K.B.Mohanty i highly enjoyable, inpiing and ewading expeience. I am highly indebted to him and expe my deep ene of gatitude fo hi guidance and uppot. I humbly acknowledge the valuable uggetion and contuctive citicim of Pof. B.D. Shubudhi, Pof. S. K Sahoo and Pof. S.K.Behea while cutinizing my eeach eult. I am highly indebted to the authoitie of NIT, Roukela fo poviding me vaiou facilitie like libay, compute and Intenet, which have been vey ueful. I expe pecial thank to all my fiend, fo being thee wheneve I needed them. Thank you vey much Kamaleh, Siniva, Baant, Amit and Benu. Finally, I am foeve indebted to my ite and my loving paent fo thei undetanding and encouagement when it wa mot equied. I dedicate thi thei to my family and fiend. Swagat Pati

6 Abtact Cetificate Acknowledgement Content CONTENTS 1 INTRODUCTION Backgound Wind tubine ytem Powe contained in wind Type of wind conveion device Woking of moden wind tubine Impotant tem elated to wind powe geneation Wind tubine chaacteitic Wind tubine contol ytem Wind powe conveion ytem Fixed peed wind tubine Vaiable peed wind tubine Geneato fo wind powe application Squiel cage induction machine Wound oto induction machine Pemanent magnet ynchonou machine Self excited and line excited induction geneato Self excited induction geneato ine excited induction geneato Contol of line excited cage induction geneato Motivation Objective Oganization of the thei 33 I II III IV

7 2. D-Q MODEING AND VECTOR CONTRO OF INDUCTION GENERATOR Intoduction Axe tanfomation D-Q model of induction machine (kon equation) Vecto o field oiented contol Equivalent cicuit and phao diagam Pinciple of vecto contol Concluion INDIRECT VECTOR CONTRO OF CAGE INDUCTION GENERATOR Intoduction Indiect vecto contol of induction geneato Simulation eult and dicuion Step change in tubine toque Step change in efeence peed command Concluion PERFORMANCE IMPROVEMENT OF FIED ORINTED INDUCTION GENERATOR USING MODERN CONTROERS Intoduction Fuzzy contolle Intoduction Fuzzy et Membehip function Fuzzy ytem Deign of fuzzy logic contolle Self tuned fuzzy logic contolle Intoduction Tuning pocedue Self tuned fuzzy logic contolle deign 82

8 4.4 Hybid contolle Intoduction Deign pinciple fo Hybid contolle Reult and dicuion Simulation with a tep change in tubine toque Simulation with a tep change in efeence peed Concluion VECTOR CONTRO OF GRID SIDE PWM CONVERTER FOR POWER FACTOR IMPROVEMENT Intoduction Maximum powe point tacking Supply ide convete contol Reult and dicuion Concluion FABRICATION AND TESTING OF CONTRO CIRCUIT FOR A BIDIRECTIONA CONVERTER- INVERTER SET USED IN INE EXCITED INDUCTION GENERATOR Intoduction Powe electonic convete Contol cicuit fo VSI Tiangula wave geneato cicuit Thee phae efeence ine wave geneato Compaato cicuit ockout cicuit Ove cuent potection cicuit Gate dive cicuit Fabicated cicuit and tet eult Concluion CONCUSION AND SCOPE FOR FUTURE WORK Concluion Scope fo futue wok 15

9 8. REFERENCES APPENDIX APPENDIX APPENDIX-3 157

10 Chapte-1 Chapte 1 Intoduction 1.1 BACKGROUND In lat 1 yea, the human civilization ha gone too fa in exploiting the limited eouce on eath, making the biophee vulneable to many uncetain lage cale diate. Many of uch cie ae due to the limited eouce fo the geneation of electical powe. The depletion of foil fuel uch a coal and oil and apidly inceaing demand of electical enegy, ha led to a wold-wide inteet in developing wind powe plant. Wind i a fee, clean, and inexhautible enegy ouce. It ha eved mankind well fo many centuie by popelling hip and diving wind tubine to gind gain and pump wate. Inteet in wind powe lagged, howeve, when cheap and plentiful petoleum poduct became available afte Wold Wa II. The high capital cot and the uncetainty of the wind placed wind powe at an economic diadvantageou poition. In the pat fou decade method of haneing hydo and wind enegy fo electic powe geneation and the technology fo uch altenate ytem ae developed. Continuou eeach i going on taking into account diffeent citical iue in thi ecto. Wind enegy i one of the mot impotant and pomiing ouce of enewable enegy all ove the wold, mainly becaue it i conideed to be nonpolluting and economically viable. At the ame time thee ha been a apid development of elated wind enegy technology. Howeve in the lat two decade, Page 1

11 Chapte-1 wind powe ha been eiouly conideed to upplement the powe geneation by foil fuel and nuclea method. 1.2 WIND TURBINE SYSTEM POWER CONTAINED IN WIND The powe contained in wind i given by the kinetic enegy of the flowing ai ma pe unit time. That i, 1 P = (ai ma pe unit time)(wind velocity) P = ρ AV V 2 Hence ( )( ) 2 1 = ρav 2 3 (1.1) whee P i the powe contained in wind(in watt), ρ i the ai denity ( kg/m 3 at 15 o C and nomal peue), A i the oto aea in m 2 and V i the wind velocity (in m/ec) without oto intefeence, i.e., ideally at infinite ditance fom the oto TYPES OF WIND CONVERSION DEVICES Wind enegy conveion device can be boadly categoized into two type accoding to thei axi alignment: hoizontal axi wind tubine and vetical axi wind tubine. Hoizontal axi wind tubine can be futhe divided into thee type. Dutch type gain ginding windmill Multiblade wate pumping windmill High-peed popelle type windmill Page 2

12 Chapte-1 Vetical axi wind tubine come in two diffeent deign The Savoniu oto The Daieu oto WORKING OF MODERN WIND TURBINES In ecent day high peed popelle type wind tubine ae motly ued a hoizontal axi wind tubine due to thei excellent aeodynamic efficiency. Among the vetical axi wind tubine the Daieu oto i moe efficient than the Savoniu oto, but the majo dawback of the Daieu oto i that it i not elf tating. The Savoniu oto i imple and inexpenive, but it efficiency i le than the Daieu oto. Figue 1.1 how the diffeent type of advanced wind tubine. (a) (b) (c) Figue 1.1 Diffeent type of wind tubine ued in ecent day (a) Hoizontal axi high peed popelle type wind tubine (b) Savoniu oto (c) Daieu oto Page 3

13 Chapte High peed popelle type wind tubine High peed popelle type wind tubine ae motly ued fo wind powe geneation. Thee tubine do not opeate on thut foce, athe they depend mainly upon the aeodynamic foce that develop when wind flow aound the blade of aeofoil deign. To undetand how a moden wind tubine wok, fit we have to undetand the aeodynamic of the aeofoil deign. Figue 1.2 how the diffeent foce acting upon the aeofoil. Figue 1.2 Foce acting upon the aeofoil Conide an aeofoil moving in the wind team with a velocity u and the wind velocity being v. The wind team at the top of the aeofoil ha to tavee a longe path than that at the bottom, leading to a diffeence in velocitie which give ie to a diffeence in peue fom which a lift foce eult and come anothe foce called the dag foce which tie to puh the aeofoil back in the diection of wind. The aggegate foce on the aeofoil i then detemined by the eultant of thee two foce. Page 4

14 Chapte-1 Figue 1.3 Foce acting upon the aeofoil when wind and aeofoil velocitie ae not along the ame line But when the aeofoil and the wind do not move along the ame line then thee foce ae detemined by the wind peed a een by the aeofoil, called the elative wind w. The elative wind i given by the vecto um of the wind velocity and the negative of the aeofoil velocity a hown in Figue 1.3. the lift foce F will now be pependicula to the elative wind, the dag foce F D will be paallel to it. The magnitude of thee two foce will be popotional to the quae of the elative wind velocity. Fom Figue 1.3 we can ee that the lift foce and the dag foce have oppoing component along the diection of motion. If the lift foce dominate the dag, thee will be a eultant foce along the diection of motion, giving a poitive puh to it. In fact thi i the foce that ceate the toque in the moden wind tubine. The blade ae of aeofoil ection, which move along the team of wind. They ae alo aligned o that the dag foce i minimized, and thi give the blade a net poitive toque. Page 5

15 Chapte-1 Thee will of coue be anothe component of the two foce that i pependicula to the diection of blade motion thi foce i called the thut foce. Thi foce tie to topple the towe and i a poblem at high peed The Savoniu oto The Savoniu oto i an extemely imple vetical axi device that wok entiely becaue of the thut foce of the wind. Aeodynamically they ae thut-type device, coniting of two o thee coop. ooking down on the oto fom above, a two-coop machine would look like an "S" hape in co ection a hown in the Figue 1.4. Becaue of the cuvatue, the coop expeience le dag when moving againt the wind than when moving with the wind. The diffeential dag caue the Savoniu tubine to pin. Becaue they ae dag-type device, Savoniu tubine extact much le of the wind' powe than othe imilaly-ized lift-type tubine. Much of the wept aea of a Savoniu oto i nea the gound, making the oveall enegy extaction le effective due to lowe wind peed at lowe height. Page 6

16 Chapte-1 Figue 1.4 Top view of a Savoniu oto The Savoniu oto i imple and inexpenive, and the mateial equied fo it i available in any ual aea, enabling on ite contuction of uch wind mill. Howeve it utility i limited becaue of it elatively low efficiency The Daieu oto In the oiginal veion of the Daieu deign, the aeofoil ae aanged o that they ae ymmetical and have zeo igging angle, that i, the angle that the aeofoil ae et elative to the tuctue on which they ae mounted. Thi aangement i equally effective no matte, which diection the wind i blowing in contat to the conventional type, which mut be otated to face into the wind. Page 7

17 Chapte-1 When the Daieu oto i pinning, the aeofoil ae moving fowad though the ai in a cicula path. Relative to the blade, thi oncoming aiflow i added vectoially to the wind, o that the eultant aiflow ceate a vaying mall poitive angle of attack to the blade. Thi geneate a net foce pointing obliquely fowad along a cetain 'line-of-action'. Thi foce can be pojected inwad pat the tubine axi at a cetain ditance, giving a poitive toque to the haft, thu helping it to otate in the diection it i aleady tavelling in. A the aeofoil move aound the back of the appaatu, the angle of attack change to the oppoite ign, but the geneated foce i till obliquely in the diection of otation, becaue the wing ae ymmetical and the igging angle i zeo. The oto pin at a ate unelated to the wind peed, and uually many time fate. The enegy aiing fom the toque and peed may be extacted and conveted into ueful powe by uing an electical geneato. Figue 1.5 how the foce acting upon the blade at diffeent blade poition. The aeonautical tem lift and dag ae, tictly peaking, foce aco and along the appoaching net elative aiflow epectively, o they ae not ueful hee. We eally want to know the tangential foce pulling the blade aound, and the adial foce acting againt the beaing. Page 8

18 Chapte-1 Figue 1.5 Foce acting upon the blade of Daieu oto at diffeent poition When the oto i tationay, no net otational foce aie, even if the wind peed ie quite high the oto mut aleady be pinning to geneate toque. Thu the deign i not nomally elf tating. The tating toque i geneally povided by an electical machine, which initially un a a moto, but late change to the geneato mode a the Daieu oto tat, geneating powe. The Daieu deign i theoetically le expenive than a conventional type, a mot of the te i in the blade which povide toque to the geneato located at the bottom of the tubine. The only foce that need to be balanced out vetically ae the compeion load due to the blade flexing outwad (thu attempting to "queeze" the towe), and the wind foce tying to Page 9

19 Chapte-1 blow the whole tubine ove, half of which i tanmitted to the bottom and the othe half of which can eaily be offet with guy wie IMPORTANT TERMS REATED TO WIND POWER GENERATION Solidity The olidity of a wind oto i the atio of the pojected blade aea to the wept aea. The pojected blade aea doen t mean the actual blade aea, it i the aeaa met by the wind o pojected in the diection of the wind a hown in Figue 1.6 Figue 1.6 Solidity of a hoizontal wind tubine The olidity of Savoniu oto i unity a the wind ee no fee paage though it. Fo Multiblade wate pumping mill, it i aound.7. fo high peed hoizontal axi tubine and Daieu oto it lie between.1 to.1. Page 1

20 Chapte-1 Solidity ha a diect elation with toque and peed. High olidity oto have high toque and low peed. On the othe hand low olidity oto have low toque and high peed and ae typically uited fo electical powe geneation Tip Speed Ratio (TSR) Tip peed atio of a wind tubine i defined a the atio of the peed of the otating blade tip to the peed of the fee team wind. λ = 2πRN V ω R T = V (1.2) Figue 1.7 Solidity of a hoizontal wind tubine whee λ i the TSR, R i the adiu of the wept aea in mete, N i the otational peed in evolution pe econd, and V i the wind peed without oto inteuptionn in m/ec. Thee i an Page 11

21 Chapte-1 optimum angle of attack which ceate the highet lift to dag atio. Becaue angle of attack i dependent on wind peed, thee i an optimum tip-peed atio. The TSR of the Savoniu oto and the multi-blade wate pumping mill ae geneally low whee a that of Daieu oto can be a high a 9. It can be aid that high olidity oto in geneal have low value TSR and vice-vea Powe coefficient (C p ) Powe coefficient of a wind enegy convete i given by (1.3) The powe coefficient diffe fom the efficiency of a wind machine in the ene that the late include the loe in the mechanical tanmiion, electical geneation, etc whee a the fome i jut the efficiency of conveion of wind enegy into mechanical enegy of the haft. In high peed hoizontal axi machine the powe coefficient i given by the Betz limit which tate that all wind powe cannot be captued by oto o ele ai would be completely till behind oto and not allow moe wind to pa though. Theoetical limit of oto efficiency i 59%. Mot moden wind tubine ae in the 35 45% ange Specific Rated Capacity (SRC) Specific ated capacity i defined a the atio of peak powe ating of the geneato to the oto wept aea. powe ating of the geneato SRC = oto wept aea (1.4) Page 12

22 Chapte-1 Since the ame wind tubine can poduce widely vaying amount of electical powe depending on the wind peed, the SRC give a tandad pocedue to pecify the ating of a machine. The SRC vaie between.2 fo mall oto to.6 fo lage oto WIND TURBINE CHARACTERISTICS The diffeent chaacteitic which define the pefomance of a wind tubine ae Powe coefficient veu Tip peed atio chaacteitic Powe veu peed chaacteitic Toque veu peed chaacteitic Powe Coefficient veu Tip Speed Ratio Chaacteitic The gaph of the powe coefficient (C p ) againt tip peed atio (TSR) i a vey impotant yadtick in the chaacteization of the wind tubine. Figue 1.8 how the C p v TSR chaacteitic fo diffeent type of tubine. Figue 1.8 Cuve of C p veu TSR fo diffeent type of wind mill Page 13

23 Chapte-1 Fo a given tubine, the powe coefficient depend not only on the TSR but alo on the blade pitch angle (α). Figue 1.9 how the typical vaiation of the powe coefficient with epect to the TSR (λ) with blade pitch contol. Figue 1.9 Cuve of C p veu TSR fo diffeent pitch angle α Powe veu Speed Chaacteitic The wind tubine powe cuve hown in Figue 1.1 illutate how the mechanical powe that can be extacted fom the wind depend on the oto peed. Fo each wind peed thee i an optimum tubine peed at which the extacted wind powe at the haft eache it maximum. Such a family of wind tubine powe cuve can be epeented by a ingle dimenionle chaacteitic cuve, namely, the C p -λ cuve, a hown in Figue 1.9, wheee the powe coefficient i plotted againt the TSR. Page 14

24 Chapte-1 Fom equation (1.1) and (1.3), the mechanical powe tanmitted to the haft i 1 P m = ρ 2 C p 3 AV (1.5) Figue 1.1 Powe veu Speed chaacteitic of a wind tubine Whee C p i a function of TSR (λ) and the pitch angle (α). Fo a wind tubine with adiu R, equation (1.5) con be expeed a P m = 1 ρ C p πr V (1.6) Fo a given wind peed, the powe extacted fom the wind i maximized if C p i maximized. The optimum value of C p, ay C p,opt, alway occu at a definite value of λ, ay λ opt, which mean that fo vaying wind peed, the oto peed hould be adjuted popotionally to adhee alway Page 15

25 Chapte-1 to thi value of λ(=λ opt ) fo maximum mechanical powe output fom the tubine. Uing the elation λ=ω R/V in equation (1.6), the maximum value of the haft mechanical powe fo any wind peed can be expeed a P max = 1 2 C p, opt π R 3 λ 5 opt ω 3 opt ρ (1.7) Thu the maximum mechanical powe that can be extacted fom wind i popotional to the cube of the oto peed, i.e., P max α ω 3 thi i hown by the dotted line in Figue Toque veu Speed Chaacteitic Studying the toque veu otational peed chaacteitic of any pime move i vey impotant fo popely matching the load and inuing the table opeation of the electical geneato. The typical toque veu peed chaacteitic of the two- blade popelle -type wind tubine, the Daieu oto, and the Savoniu ae hown in Figue 1.11, 1.12, 1.13 epectively. The pofile of the toque peed cuve hown in Figue 1.11, 1.12 and 1.13 follow fom the powe cuve, ince toque and powe ae elated a follow Pm T m = ω (1.8) Fom equation (1.7), at the optimum opeation point (C p, opt, λ opt ) the elation between aeodynamic toque and otational peed i T m = 1 2 ρc p, opt R π λ 5 3 opt ω 2 opt (1.9) Page 16

26 Chapte-1 It i een that at the optimum opeation point on the Cp-λλ cuve, the toque i quadatically elated to the otational peed. Figue 1.11 Toque veu Speed chaacteitic of two blade popelle type oto Figue 1.12 Toque veu Speed chaacteitic of Daieu oto Page 17

27 Chapte-1 Figue 1.13 Toque veu Speed chaacteitic of Savoniu oto The cuve in the figue how that fo the popelle tubine and the Daieu oto, fo any wind peed, the toque eache a maximum value at a pecific otational peed, and thi maximum haft toque vaie appoximately a the quae of the otational peed. In thi cae of electicity poduction, the load toque depend on the electical loading, and by popely chooing the load (o powe electonic inteface), the toque can be made to vay a the quae of the otational peed WIND TURBINE CONTRO SYSTEMS Contol ytem ae equied fo a wind tubine fo efficient powe captue fom wind a well a fo afety of the tubine itelf. When the wind peed become high, it become impotant to potect the geneato and powe electonic device fom oveloading which i done by educing the dive tain load. At vey high peed the wind tubine ha to be talled. At low and medium wind peed the tubine ha to efficiently captue the powe contained in the wind fo which the angle of attack of the tubine blade hould be accodingly adjuted. Similaly at vey low peed Page 18

28 Chapte-1 the powe contained in the wind become too low to be captued. So the tubine need to be topped. Along with many opeating chaacteitic, the technical data heet of a tubine mention it output at a paticula wind peed, geneally known a the ated wind peed. Thi i the minimum wind peed at which the wind tubine poduce it deignated output powe. Fo mot of the tubine, thi peed i nomally between 9 and 16 m/. The geneato ating i choen o a to bet utilize the mechanical output of the tubine at the ated wind peed. Wind tubine ha fou diffeent type of contol mechanim, a dicued in the following Pitch Angle Contol In thi type of contol the pitch angle of the blade ae changed accoding to the vaiation of wind peed. A the wind peed change the pitch angle contol ytem align the blade in diection of the elative wind due to which it i poible to achieve a high efficiency of powe conveion. Figue 1.14 Pitch angle contol block diagam Page 19

29 Chapte-1 In a pitch contolled machine, a the wind peed exceed it ated peed, the blade ae gadually tuned about the longitudinal axi and out of the wind to inceae the pitch angle. Thi educe the aeodynamic efficiency of the oto, and oto output powe deceae. When the wind peed exceed the afe limit fo the ytem, the pitch angle i o changed that the powe output educe to zeo and the machine hift to the tall mode. Afte the gut pae, the pitch angle i eet to the nomal poition and the tubine i etated. At nomal wind peed, the blade pitch angle hould ideally ettle to a value at which the output powe equal the ated powe. The pitch angle contol pinciple i explained in Figue The eo ignal which i the diffeence between the output electical powe and efeence powe i fed a the input to the pitch contolle. The pitch contolle opeate the blade actuato to alte the pitch angle. The contol ytem et the blade at uch an angle that maximize the oto efficiency while opeating below the ated peed. The geneato output powe i accodingly adjuted uch that the geneato i able to abob the mechanical powe fom the tubine and delive it to the load. A continuou pitch contol i elatively expenive to implement, o it i not jutified to ue thi type of contol mechanim in mall wind machine. Howeve, the talling mechanim mut be ued in all type of wind tubine (lage,medium and mall) to pevent damage of the tubine duing tubulent weathe condition Stall Contol Paive Stall Contol Geneally, tall contol to limit the powe output at high wind i applied to contant- pitch tubine diving induction geneato connected to the netwok. The oto peed i fixed by the netwok, allowing only 1-4% vaiation. Paive tall contolled wind Page 2

30 Chapte-1 tubine have a imple fom of blade that ae attached to the hub at a fixed angle. The oto aifoil pofile i aeodynamically deigned uch that when the wind peed exceed a afe limit, the angle of attack of the aifoil to the wind team i inceaed, and the lamina flow top and i eplaced by tubulence on the top ide of the aifoil, due to which the lift foce top acting talling it otation. Active Stall Contol age wind tubine ae equipped with active tall contol mechanim. In thi cae they ue pitchable blade eembling the pitch contolled tubine. To get a lage toque o tuning foce at low peed, the contol ytem pitche the blade in tep like pitch angle contolled machine at low wind peed. But the ituation become diffeent when the tubine eache it deigned ated powe level. At that time the tall contol mechanim act diffeently fom a pitch contol mechanim. At high peed, to potect the geneato fom oveloading the active tall contol ytem pitche the blade in the oppoite diection of what a pitch contolled machine would do. In thi cae it inceae the angle of attack of the aeofoil leading a tall condition athe than deceaing the angle of attack to educe the lift and the otational peed of the blade. An advantage of the active tall contol i that the powe output can be contolled o a to avoid ovehooting the geneato ated powe at the tat of wind gut. A econd advantage i that the geneato would delive it ated powe at high wind peed, in contat to the paive tall contolled machine which will nomally expeience a dop in thei electical powe output ince it oto blade expeience a deepe tall at high wind peed. Page 21

31 Chapte Powe Electonic Contol In a ytem incopoating a powe electonic inteface between the geneato and the load (o the gid), the electical powe deliveed by the geneato to the load can be dynamically contolled. The intantaneou diffeence between mechanical powe and electical powe change the oto peed following the equation dω P m Pe J = dt ω (1.1) Whee J i the pola moment of the inetia of the oto, ω i the angula peed of the oto, P m i the mechanical powe poduced by the tubine, and P e i the electical powe deliveed to the load. Integating equation (1.1), we get 1 2 J t2 2 2 ( ω ω ) = ( P P )dt 2 1 m t1 e (1.11) The advantage of thi method of peed contol i that it doe not involve any mechanical action and i mooth in opeation. A diadvantage i that fat vaiation of peed equie a lage diffeence between the input powe and output powe, which cale a the moment of inetia of the oto. Thi eult in a lage toque and hence inceaed te on the blade. Moeove, continuou contol of the oto peed by thi method implie continuou fluctuation of the powe output to the gid, which i uually undeiable fo the powe ytem Yaw Contol In thi type of contol the tubine continuouly oiented along the diection of wind flow. In lage machine thi can be achieved uing motoized contol ytem activated eithe by a fan- Page 22

32 Chapte-1 tail (a mall tubine mounted pependicula to the main tubine) o, in cae of wind fam, by a centalized intument fo the detection of the wind diection whee a in mall tubine thi i achieved with a tail-vane. It i alo poible to achieve yaw contol without any additional mechanim, imply by mounting the tubine downwind o that the thut foce automatically puhe the tubine in the diection of the wind. The yaw contol mechanim can alo be ued fo peed contol the oto i made to face away fom the wind diection at high wind peed, theeby educing the mechanical powe. Howeve, thi method i eldom ued whee pitch contol i available, becaue of the tee it poduce on the oto blade. Yawing often poduce loud noie, and it i deiable to etict the yawing ate in lage machine to educe the noie. 1.3 WIND POWER CONVERSION SYSTEMS Wind tubine can opeate with eithe fixed peed (actually within a peed ange about 1%) o vaiable peed. Fo fixed-peed wind tubine, the geneato (induction geneato) i diectly connected to the gid. Since the peed i almot fixed to the gid fequency, and mot cetainly not contollable, it i not poible to toe the tubulence of the wind in fom of otational enegy. Theefoe, fo a fixed-peed ytem the tubulence of the wind will eult in powe vaiation, and thu affect the powe quality of the gid. Fo a vaiable-peed wind tubine the geneato i contolled by powe electonic equipment, which make it poible to contol the oto peed. In thi way the powe fluctuation caued by wind vaiation can be moe o le abobed by changing the oto peed and thu powe vaiation oiginating fom the wind conveion and the dive tain can be educed. Hence, the powe quality impact caued by the wind tubine can be impoved compaed to a fixed-peed tubine. The otational peed of a wind tubine i faily low and mut theefoe be adjuted to the electical fequency. Thi can be done Page 23

33 Chapte-1 in two way: with a geabox o with the numbe of pole pai of the geneato. The numbe of pole pai et the mechanical peed of the geneato with epect to the electical fequency and the geabox adjut the oto peed of the tubine to the mechanical peed of the geneato FIXED SPEED WIND TURBINE Fo the fixed-peed wind tubine the induction geneato i diectly connected to the electical gid accoding to Figue The oto peed of the fixed-peed wind tubine i in pinciple detemined by a geabox and the pole-pai numbe of the geneato. The fixed-peed wind tubine ytem ha often two fixed peed. Thi i accomplihed by uing two geneato with diffeent ating and pole pai, o it can be a geneato with two winding having diffeent ating and pole pai. Thi lead to inceaed aeodynamic captue a well a educed Figue 1.15 Fixed peed wind tubine ytem magnetizing loe at low wind peed. Thi ytem (one o two-peed) wa the conventional concept ued by many Danih manufactue in the 198 and VARIABE SPEED WIND TURBINE The ytem peented in Figue 1.16 conit of a wind tubine equipped with a convete connected to the tato of the geneato. Page 24

34 Chapte-1 Figue 1.16 Vaiable peed wind tubine ytem The geneato could eithe be a cage-ba induction geneato o a ynchonou geneato. The geabox i deigned o that maximum oto peed coepond to ated peed of the geneato. Synchonou geneato o pemanent-magnet ynchonou geneato can be deigned with multiple pole which imply that thee i no need fo a geabox. Since thi full-powe convete/geneato ytem i commonly ued fo othe application, one advantage with thi ytem i it well-developed and obut contol. 1.4 GENERATORS FOR WIND POWER APPICATIONS Geneally thee diffeent type of machine ae ued a geneato fo wind powe application, thoe ae Squiel cage induction machine (SCIM) Wound oto induction machine (WRIM) Pemanent magnet ynchonou machine (PMSM) SQUIRRE CAGE INDUCTION MACHINE Squiel cage induction machine ae motly ued a geneato fo wind powe application. Thee machine ae obut, maintenance fee and cheape than the othe type of geneato ued Page 25

35 Chapte-1 fo wind powe application. Squiel cage machine ae ued a gid excited induction geneato which take the eactive powe fom the gid and delive active powe to the gid. Figue 1.17 Squiel cage induction machine ued fo wind powe geneation Figue 1.17 how the chematic diagam fo a quiel cage induction machine ued fo wind powe geneation WOUND ROTOR INDUCTION MACHINE In ecent day wound oto induction machine have been extenively ued a geneato fo wind powe application. Thee machine have attacted the inteet t due to thei geate efficiency of powe geneation. Thee machine ae upplied both fom the tato and oto ide o often they ae called doubly excited induction geneato. In thi type of ytem the whole contol tuctue i connected to the oto ide, o the ating of the contol cicuit component ae educed. Figue 1.18 how the chematic diagam fo a wound oto induction machine ued fo wind powe geneation. Page 26

36 Chapte-1 Figue 1.18 Wound oto induction machine ued fo wind powe geneation PERMANENT MAGNET SYNCHRONOUS MACHINE Pemanent magnet ynchonou machine can alo be ued a geneato fo wind powe application. But thee machine ae uually not pefeed fo wind powe geneation pupoe due to the fact that thee machine ae cotly but they have an advantage of being ued a diect dive geneato. The cheme uing pemanent magnet ynchonou geneato i hown in Figue Figue 1.19 Pemanent magnet ynchonou machine ued fo wind powe geneation Thi wok i extenively done upon wind powe geneation uing quiel cage induction machine a geneato. Page 27

37 Chapte SEF EXCITED AND INE EXCITED INDUCTION GENERATORS The quiel cage induction geneato ae baically ued in two diffeent configuation fo wind powe geneation pupoe. Self excited induction geneato ine excited inductionn geneato SEF EXCITED INDUCTION GENERATORS Self excited induction geneato ae baically ued fo tand-alone wind powe ytem. In thi cheme a capacito bank i connected to the ytem to upply the equied eactive powe to the induction geneato. The elf excited induction geneato cheme i hown in the Figue 1.2 Figue 1.2 Self excited induction geneato cheme INE EXCITED INDUCTION GENERATORS Squiel cage induction machine ae mot often ued a line excited induction geneato fo wind powe application. In thi cheme the induction geneato ae connected to the gid though a bidiectional convete-invete et. The induction geneato take the equied eactive Page 28

38 Chapte-1 powe fom the geneato ide invete and geneate active powe which i then fed to the gid. Fo the fact that the induction geneato take the eactive powe and delive active powe, it ha a poo powe facto at the geneation end. But by the vecto contol of the line ide convete the powe facto at the gid end can be maintained pefectly at unity, whichh will be decibed in detail in chapte 6. Figue 1.21 how the line excited induction geneato cheme fo wind powe application. Figue 1.21 ine excited induction geneato cheme 1.6 CONTRO OF INE EXCITED CAGE INDUCTION GENERATORS ine excited cage induction geneato ae mot commonly ued fo wind powe application. Thee geneato ae obut, cheape than it counte pat and need le maintenance, which make thee machine uitable fo wind powe geneation. Cage induction geneato have dawback that, due to the coupling effect between active and eactivee powe the tanient epone become luggih and the contol become difficult and complex. Becaue of thi thee aie tability poblem when the ytem i connected with the gid. A lot of eeach ha been done in ecent pat to impove the tanient chaacteitic of induction machine. When induction machine ae opeated uing vecto contol technique, fat dynamic epone and accuate toque contol ae obtained. All of thee chaacteitic ae advantageou in vaiable Page 29

39 Chapte-1 peed wind enegy conveion ytem (WECS). Squiel cage geneato with hunt paive o active VAR (volt ampee eactive) geneato wa popoed in [1], which geneate contant fequency powe though a diode ectifie and line commutated thyito invete. A compaative tudy of fixed peed and DFIG duing powe ytem ditubance uch a netwok voltage ag and thee phae fault, a well a the poibility of netwok voltage intability i invetigated in [2]. The pefomance of a DFIG diven by a wind tubine connected to lage powe ytem i tudied in [3], whee a in [4] a doubly excited induction geneato i tudied a an altenative to line excited cage induction geneato fo vaiable peed wind powe geneation. In thi pape a feed fowad vecto contol cheme i alo developed fo the pefomance impovement of the doubly fed induction geneato ytem. A compaative tudy i done in [5] between fixed peed wind tubine, vaiable peed wind tubine employing line excited cage geneato and vaiable peed wind tubine uing doubly excited induction geneato. Self excited induction geneato ytem uing cage induction machine i decibed in [6], and in [7] the opeation of eveal elf excited induction geneato connected to a common bu i analyzed. The field oiented contol of induction geneato fo vaiable peed wind enegy application ae dicued in [8]-[12]. A eno-le vecto contol cheme baed on a model efeence adaptive ytem (MRAS) obeve ued to etimate the otational peed, which i uitable to contol cage induction geneato fo wind powe application i dicued in [8] In thi pape a epaate etimation of the peed i obtained fom the oto lot hamonic uing an algoithm fo pectal analyi in ode to tune the MRAS obeve and compenate fo the paamete vaiation and uncetaintie. In [9] a doubly fed induction machine i conideed while it i connected to the gid and opeating in ub ynchonou a well a upe ynchonou peed. In ode to decouple the active and eactive powe geneated by the machine, tato flux oiented vecto contol i applied in thi pape. A Page 3

40 Chapte-1 new contol cheme uing non-linea contolle and FC i employed fo a vaiable peed gid connected wind enegy ytem in [1] whee a a vecto contol cheme fo both upply ide and machine convete i dicued and the independent contol of active and eactive powe i done in [11]. In [4] and [8] -[11] the vecto contol cheme employ PI contolle fo the contol pupoe. In [12] a cage induction machine i conideed and a fuzzy contol ytem i ued to dive the wind enegy conveion ytem to the point of maximum enegy captue fo a given wind velocity. A FC baed peed contol cheme i decibed in [13] employing feed-fowad vecto contol cheme fo pefomance impovement of an induction moto dive ytem. Again in [14] fuzzy logic i ued to develop an advanced and intelligent contol tategy fo a line excited cage geneato ytem ued fo wind powe application. A detailed appoach on fuzzy logic contolle i given in [15]. In thi pape diffeent apect of fuzzy contolle tuning uch a effect of membehip function on fuzzy contolle tuning, tuning of fuzzy contolle uing the input and output nomalizing facto, effect of fuzzy ule on tuning etc. ae dicued in a vey detailed manne. In [16] method fo impoving the pefomance of a fuzzy logic contolle epecially when ued fo contol of highe ode ytem ae dicued. In thi pape two diffeent cheme fo impoviing the pefomance of a fuzzy logic contolle ae given. In [17] a elf tuned fuzzy logic contolle i implemented fo the pefomance impovement of a field oiented contol of an induction moto dive. In thi pape anothe fuzzy logic contolle i ued to tune the nomalization facto of the main fuzzy logic contolle. In [18] a imila tategy ha been adopted to tune the output nomalization facto of the fuzzy logic contolle. The output nomalization facto tuning cheme wok taking the eo and change of eo of the ytem into account. Seveal othe elf tuned fuzzy logic contolle cheme ae given in [19] [23]. In [24] and [25] hybid contolle ae decibed. In [24] the hybid contolle i a hybid of PI contolle Page 31

41 Chapte-1 and fuzzy logic contolle whee a in [25] the hybid contolle i a combination of a PI contolle and a liding mode contolle. 1.7 MOTIVATION Geneation of pollution fee powe ha become the main aim of the eeache in the field of electical powe geneation. The depletion of foil fuel, uch a coal and oil, alo aid to the impotance of witching to enewable and non-polluting enegy ouce uch a ola, tidal and wind enegy etc., among which wind enegy i the mot cot efficient and wide pead ouce of enegy. Fom the ecent cenaio it i alo evident that wind enegy i dawing a geat deal of inteet in the powe geneation ecto. If the wind enegy could be effectively captued it could olve the poblem uch a envionmental pollution and unavailability of foil fuel in futue. The above fact give the motivation fo development of a wind powe geneation ytem which would have bette pefomance and efficiency. 1.8 OBJECTIVES Wind enegy ha been utilized by human fo centuie but in the lat fou decade eiou eeach ha been done fo the geneation of electical powe fom wind. A the eeach aea i not o old, many development ae yet to be done in thi field. A numbe of wind powe conveion ytem have been developed uing diffeent type of machine uch a, cage induction machine, wound oto induction machine and pemanent magnet ynchonou machine, a geneato. Thi wok employ a cage induction machine a electical powe geneato due to the fact that cage induction machine ae cheape than thei countepat and alo need le maintenance. A lot of eeach ha been done in impoving the tanient and teady tate pefomance of the induction geneato ytem by uing diffeent contol tategie Page 32

42 Chapte-1 uch a diect and indiect vecto contol, eno-le vecto contol, diect toque contol etc. But mot of the contol tategie employed the conventional PI contolle and ome employed fuzzy logic contolle fo the contol of the induction machine. Again the powe facto of the induction geneato ytem become a big iue, becaue induction geneato have low powe facto a they take the eactive powe fom the gid and upply active powe to the gid. In thi wok the main objective ae Development and Implementation of new contolle fo tanient and teady tate pefomance impovement of the line excited induction geneato ytem. Powe facto impovement of the wind enegy conveion ytem. Fabication of a contol cicuit fo contol of PWM convete- invete et which could be intefaced with PC. 1.9 ORGANISATION OF THE THESIS The thei include ix chapte among which chapte-1 give a bief deciption of wind powe and wind electical ytem. In chapte-2 the d-q modeling of induction geneato i done and the vecto contol tategy fo induction machine i decibed. Chapte-3 include the deciption and imulation eult of an indiect vecto contolled cage induction geneato. The indiect vecto contol tategy decibed in thi chapte employ conventional PI contolle. The imulation eult ae taken fo both tubine toque and efeence peed vaiation. In chapte-4 thee contolle ae deigned and implemented fo the pefomance impovement of the indiect vecto contolled cage induction geneato ytem. Among the thee contolle the fit i the fuzzy logic contolle. Then a econd contolle i deigned which i the elf tuned fuzzy logic contolle. The thid contolle i a hybid contolle which employ both conventional PI Page 33

43 Chapte-1 contolle and the elf tuned fuzzy logic contolle. The impovement in the pefomance of the cage induction geneato ytem i hown in the imulation late in that chapte. In chapte-5 a contol cheme fo the gid ide PWM convete i decibed and imulated. The contol of gid ide convete i done to impove the powe facto of the wind powe geneation ytem. Chapte-6 contain the detail of the fabication of the contol cicuit fo contol of PWM convete- invete et. The output of the fabicated cicuit ae hown late in that chapte. The main contibution of the thei ae:- 1. Pefomance impovement of indiect vecto contolled induction geneato uing: i. Fuzzy logic contolle. ii. iii. Self tuned fuzzy logic contolle. A novel hybid contolle combining P-I contolle and elf tuned fuzzy logic contolle. 2. Pefomance compaion of the indiect vecto contol cheme with diffeent contolle. 3. Powe facto impovement of wind powe geneation ytem though contol of gid ide convete. 4. Fabication and teting of contol cicuit fo PWM-convete-invete ytem. Page 34

44 Chapte-2 Chapte 2 D-Q Modeling And Vecto Contol of Induction Geneato 2.1 INTRODUCTION In many application, the dynamic behavio of the induction machine ha an impotant effect upon the oveall pefomance of the ytem of which it i a pat. A machine i a complex tuctue electically, mechanically and themally. The dynamic pefomance of an ac machine i complex becaue the thee phae oto winding move with epect to the thee phae tato winding. The machine model can be decibed by diffeential equation with time vaying mutual inductance, but uch a model tend to be vey complex. The thee phae machine can be epeented by an equivalent two-phae machine i.e. a-b-c to d-q tanfomation. In the192, to ovecome the poblem of time vaying paamete, R.H. Pak popoed a new theoy of electical machine analyi. He tanfomed o efeed the tato vaiable (voltage, cuent and flux linkage) to a ynchonouly otating efeence fame fixed in the oto. ate, in the 193, H.C. Stanley howed that time vaying inductance in the voltage equation of an induction machine due to electic cicuit in elative motion can be eliminated by tanfoming Page 35

45 Chapte-2 the oto vaiable to vaiable aociated with fictitiou tationay winding. ate, G. Kon popoed a tanfomation of both tato and oto vaiable to a ynchonouly otating efeence fame that move with the otating magnetic field. A pope model fo the thee phae induction machine i eential to imulate and tudy the complete dive ytem. 2.2 AXES TRANSFORMATION Conide a ymmetical thee-phae induction machine with tationay a-b-c axe at 2π/3-angle apat a hown in Figue 2.1. We have to tanfom the thee phae tationay efeence fame (a-b-c) vaiable into two-phae tationay efeence fame ( d - q ) vaiable and then tanfom thee to ynchonouly otating efeence fame (d e - q e ), and vice vea. Auming that the d - q axe ae oiented at θ angle, a hown in Figue 2.1, the voltage v d and v q can be eolved into a-b-c component and can be epeented in the matix fom a v v v a b c coθ o = co( θ 12 ) o co( θ + 12 ) inθ o in( θ 12 ) o in( θ + 12 ) 1 v 1 v 1 v q d (2.1) The coeponding invee elation i v v v q d o coθ = inθ 3.5 o co( θ 12 ) o in( θ 12 ).5 o co( θ + 12 ) v in( θ + 12 ) v.5 v 2 o a b c ( 2.2) Page 36

46 Chapte-2 b V b V q q - axi c V c V d d - axi V a a Figue 2.1 Stationay fame a-b-c to d q axe tanfomation whee v o i added a the zeo equence component, which may o may not be peent. We have conideed voltage a vaiable. The cuent and flux linkage can be tanfomed by imila equation. Figue 2.2 how the ynchonouly otating d e -q e axe, which otate at ynchonou peed ω e with epect to the d -q axe and the angle θ e =ω e t. The two-phae d - q winding ae tanfomed into the hypothetical winding mounted on the d e - q e axe. The voltage v d and v q can be eolved into d e - q e component and can be epeented in matix fom a v v q d coθ e = inθe inθ e v coθe v q d ( 2.3) Fo convenience, the upecipt e ha been dopped fom the ynchonouly otating fame paamete. The coeponding invee elation i Page 37

47 Chapte-2 v v q d coθe = inθe inθe v coθ e v q d ( 2.4) e q v d = Vmin(θ e + Φ) V v q = V m coφ θe = ωet vd = VminΦ vq = Vmco(θ e + Φ) q θ e e d ω e d Figue 2.2 Stationay fame d q to ynchonouly otating fame d e q e tanfomation 2.3 D-Q MODE OF INDUCTION MACHINE (KRON S EQUATION) G. Kon intoduced a change of vaiable that eliminated the poition o time-vaying mutual inductance of a ymmetical induction machine by tanfoming both the tato vaiable and the oto vaiable to a efeence fame otating in ynchonim with the otating magnetic field. Thi efeence fame i commonly efeed to a the ynchonouly otating efeence fame. Conide the two-phae machine hown in Figue 2.3, we need to epeent both d - q and d - q cicuit and thei vaiable in a ynchonouly otating d e - q e fame. Fo implicity, the following aumption about the induction machine ae made: Symmetical two-pole, thee phae winding. Page 38

48 Chapte-2 The lotting effect ae neglected. Mutual inductance ae equal. The flux denity i adial in the ai gap and atuation of the magnetic cicuit i neglected. The tato and the oto winding ae implified a a ingle, multi-tun full pitch coil ituated on the two ide of the ai gap. The hamonic in voltage and cuent ae neglected. Hyteei and eddy cuent loe and kin effect ae neglected. ω q θ q d d Figue 2.3 Equivalent two-phae tanfomation The tato cicuit equation can be witten a v v q d d = Riq + Ψq (2.5) dt d = Rid + Ψd (2.6) dt Page 39

49 Chapte-2 whee Ψ q and Ψ d ae q-axi and d-axi tato flux linkage, epectively. When thee equation ae conveted to d e - q e fame, the following equation can be witten: d v q = Riq + Ψ q + ωeψ d (2.7) dt v d d = Rid + Ψ d ωeψ q (2.8) dt If the oto i not moving, that i, ω =, the oto equation fo a doubly-fed wound-oto machine will be d v q = Riq + Ψ q + ωeψ d (2.9) dt v d d = Rid + Ψ d ωeψ q (2.1) dt whee all the vaiable and paamete ae efeed to the tato. Since the oto actually move at peed ω, the d-q axe fixed on the oto move at a peed ωe ω elative to the ynchonouly otating fame. Theefoe, in e e q d fame, the oto equation hould be modified a d v q = Riq + Ψ q + ( ωe ω ) Ψ d dt (2.11) d v d = Rid + Ψ d ( ωe ω ) Ψ q dt (2.12) The e e q d dynamic model equivalent cicuit ae hown in Figue 2.21 that atifie equation (2.7)-(2.8) and (2.11)-(2.12). The advantage of the e e q d dynamic model of the machine i that all the inuoidal vaiable in tationay fame appea a dc quantitie in ynchonou fame. Page 4

50 Chapte-2 iq l = m l = m iq R ωeψ d (ωe ω )ψd R Vq ψq m ψq Vq (a) Figue 2.4 Dynamic e e q d equivalent cicuit of machine (a) q axi cicuit e id l = m l = m id R ωeψ q (ωe ω)ψq R Vd ψd m ψd Vd (b) Figue 2.4 Dynamic e e e d q equivalent cicuit of machine (b) d axi cicuit The flux linkage expeion in tem of the cuent can be witten fom Figue 2.4 a: Ψ = i + i + i ) (2.13) q l q m( q q Ψ = i + i + i ) (2.14) q l q m ( q q Ψ qm = m ( iq + iq ) (2.15) Ψ = i + i + i ) (2.16) d l d m( d d Ψ = i + i + i ) (2.17) d l d m( d d Page 41

51 Chapte-2 Page 42 ) ( d d m dm i i Ψ + = ) (2.18 Combining the above expeion, the electical tanient model in tem of voltage and cuent can be given in matix fom a ( ) ( ) ( ) ( ) = q d q d e m m e e m e m m m e e m e m e q d q d i i i i R R R R v v v v ω ω ω ω ω ω ω ω ω ω ω ω (2.19) whee i the aplace opeato. Fo ingly-fed machine, uch a a cage moto, v q =v d =. Now plitting equation (2.19) uch that the diffeential tem become epaate and ewiting the equation we get q d q d V V V V = ( ) ( ) ( ) ( ) e m e e m e m e e m e e R R R R ω ω ω ω ω ω ω ω ω ω ω ω q d q d i i i i + m m m m q d q d i i i i (2.2) whee q d q d V V V V = U, q d q d i i i i = X &, q d q d i i i i = X

52 Chapte-2 Page 43 ( ) ( ) ( ) ( ) e m e e m e m e e m e e R R R R ω ω ω ω ω ω ω ω ω ω ω ω = A 1 and m m m m = A 2 So we have the equation a U = A 1 X + A 2 X & (2.21) Reaanging we get X& = A A 1 X A I U (2.22) Whee 1 2 A = 2 1 m m m m m and I i the identity matix.

53 Chapte-2 1 Subtituting the value of A 1, A and I in equation (2.21) we get ou tate equation in the fom 2 X& = A X + B U (2.23) Whee and 1 2 A = - A A 1 B = A 1 2 I The matix A ha ome value which ae contant and ome value which ae function of ω. Now epaating out the ω dependent tem fom the matix A and ewiting the equation we get the equation in the fom of X&. = A X + A X + B U (2.24) Whee matix A i a contant matix which i independent of ω but the matix A i dependent on ω and can be witten a Whee A i a contant matix. A = ω * A Hence the final equation i of the fom given below X& = A X + ω * A X + B U (2.25) Page 44

54 Chapte-2 Page 45 And i given by the equation 2.26 q d q d i i i i = m e m m e m m m m m m e m m e m R R R R R R R R ω ω ω ω q d q d i i i i + ω m m m m m m m m m m m m m m q d q d i i i i m m m m m m m m m m m m q d q d V V V V (2.26) The toque equation fo moto can be given a m m e B dt d J T T ω ω + + = (2.27)

55 Chapte-2 And the toque equation fo geneato can be given a ω m + d Te + Ttubine = J Bωm (2.28) dt whee T =load toque, T tubine = tubine toque, J=oto inetia, ω m =mechanical peed =2/p ω, ω = i the electical peed of the oto and P= pole pae of the machine. The expeion fo the developed toque can be deived a Te = 3 2 P 2 ( Ψ i Ψ i ) dm q qm d = = = P 2 P 2 P 2 ( Ψ i Ψ i ) d q q d ( Ψ i Ψ i ) d q q d ( Ψ i Ψ i ) dm q qm d = 3 2 P m 2 ( i i i i ) q d d q (2.29) Equation (2.26), (2.27),(2.28) and (2.29) give the complete model of the electo-mechanical dynamic of an induction machine in ynchonou fame. 2.4 VECTOR OR FIED ORIENTED CONTRO The cala contol technique i imple to implement, but due to inheent coupling effect i.e. both toque and flux ae function of voltage o cuent and fequency, give luggih epone due to which the ytem become eaily pone to intability becaue of highe ode ytem effect. Thi poblem can be olved by vecto o field-oiented contol. By thi contol technique the induction machine can be contolled like a epaately excited dc machine. Becaue Page 46

56 Chapte-2 of dc machine-like pefomance, vecto contol i alo known a decoupling, othogonal, o tanvecto contol. Vecto contol i applicable to both induction and ynchonou machine dive. Conide the epaately excited dc machine a hown in Figue 2.5. The developed toque i given by T = K I I ( 2.3) e t a f whee I a = amatue cuent and I f =field cuent. The contuction of dc machine i uch that the field flux Ψ f poduced by cuent I f i pependicula to the amatue flux Ψ a, which i poduced by amatue cuent I a. Thee pace vecto, which ae tationay in pace ae othogonal o decoupled in natue. Thi mean that when toque i contolled by contolling the cuent I a, the flux Ψ f i not affected. DC machine-like pefomance can alo be extended to an induction moto if the machine e e contol i conideed in a ynchonouly otating efeence fame ( d q ), whee the inuoidal vaiable appea a dc quantitie in teady tate. Figue 2.6 how the induction machine with the invete and vecto contol with the two contol cuent input, * id and * iq With vecto contol, i d i analogou to field cuent If and i q i analogou to amatue cuent I a of a dc machine. Theefoe, the toque equation can be expeed a T e = KΨˆ i ( 2.31) t q o T = K i i ( 2.32) e t d q The dc machine like pefomance i only poible if the i d i aligned in the diection of Ψˆ and i q i etablihed pependicula to it. Thi mean that when * i q i contolled, it affect the actual Page 47

57 Chapte-2 i q cuent only, but doe not affect the flux Ψˆ. Similaly, when flux only and doe not affect the i q component of cuent. i i contolled, it contol the * d Figue 2.5 Sepaately excited dc machine Figue 2.6 Vecto-contolled induction machine EQUIVAENT CIRCUIT AND PHASOR DIAGRAM Conide the e d q e equivalent cicuit diagam of induction machine unde teady tate condition a hown in Figue 2.7. The oto leakage inductance l i neglected fo implicity, which make the oto flux Ψˆ the ame a the ai gap flux Ψˆ m. The ta ato cuent Î can be expeed a I ˆ = i + i 2 d 2 q ( 2.33) whee i d = magnetizing component of tato cuent flowing though the inductance m and i q = toque component of tato cuent flowing in the oto cicuit. Figue 2.8 and Figue 2.9 how phao diagam in e e d q fa ame with peak value of inuoid and ai gap voltage Vˆ m aligned on Page 48

58 Chapte-2 e the q axi. The in-phae o toque component of cuent i q contibute the active powe aco the ai gap, wheea the eactive o flux component of cuent i d contibute only eactive powe. Figue 2.8 indicate an inceae of the i q component of tato cuent to inceae the toque while maintaining the flux Ψ contant, wheea Figue 2.9 indicat te a weakening of the flux by educing the i d component. Figue 2.7 Complex (qd) equivalent cicuit in teady tate Figue 2.8 Steady-tatee phao diagam with inceae of toque component of cuent Page 49

59 Chapte-2 Figue 2.9 Steady-tate phao diagam with inceae of flux component of cuent PRINCIPE OF VECTOR CONTRO The fundamental of vecto contol implementation can be explained with the help of Figue 2.1, whee the machine model i epeented in a ynchonouly otating efeence fame. The invete i omitted fom the figue, auming that it ha unity cuent gain, that i, Contol Machine * i d d e -q e to d -q * i * q i * i d q d -q to a-b-c * i a * i b * i c i a i b i c a-b-c to d -q i d i q d -q to d e -q e i d i q Machine d e -q e model i q co θ e in θ e co θe in θ e i d ω e Ψ Invee tanfomation Tanfomation Figue 2.1 Vecto contol implementation pinciple with machine e e d q model Page 5

60 Chapte-2 * * it geneate cuent i, a i b, and i a dictated by the coeponding command cuent c i, a i, b and i * fom the contolle. A machine model with intenal conveion i hown on the ight. The c machine teminal phae cuent i a, i, and b i ae conveted to c i d and i q component by 3 Φ/ 2Φ tanfomation. Thee ae then conveted to ynchonouly otating fame by the unit vecto component coθ e and inθ e befoe applying them to the e e d q machine model a hown. The contolle make two tage of invee tanfomation, o that the contol cuent i * d and * i q coepond to the machine cuent i d and i q epectively. In addition, the unit vecto aue coect alignment of i d cuent with the flux vecto Ψ and i q pependicula to it. Thee ae eentially two geneal method of vecto contol. One, called the diect o feedback method, wa invented by Blachke and the othe known a the indiect o feed-fowad method wa invented by Hae. Thee two method ae diffeent eentially by how the unit vecto i geneated fo the contol. 2.5 CONCUSION In thi chapte the voltage and flux equation of the induction machine ae dicued. The induction machine i modeled in the ynchonouly otating efeence fame and the final equation of the induction machine i epeented in tate pace uing d and q- axi tato and oto cuent a vaiable. The vecto contol tategy i alo dicued in the chapte. The vecto contol technique and the tate pace equation of the induction machine ae ued in the coming chapte fo imulation of the induction geneato ytem. Page 51

61 Chapte3 Chapte 3 Indiect vecto contol of cage induction geneato 3.1 INTRODUCTION The contol and etimation of wind enegy conveion ytem contitute a vat ubject and ae moe complex than thoe of dc dive. Induction geneato with cage type oto have been ued extenively in wind powe geneation ytem fo the vaiable peed application in a wide powe ange. Geneally, vaiable peed wind enegy conveion ytem with Induction geneato equie both wide opeating ange of peed and fat toque epone, egadle of any ditubance and uncetaintie (tubine toque vaiation, paamete vaiation and un-modelled dynamic). Thi lead to moe advanced contol method to meet the eal demand. The ecent advance in the aea of field-oiented contol along with the apid development and cot eduction of powe electonic device and micopoceo have made vaiable peed wind enegy conveion ytem an economical altenative fo wind powe application. The complexity of wind enegy conveion ytem inceae ubtantially if high pefomance ae demanded. The main eaon fo thi complexity ae the need of vaiable fequency, hamonically optimum convete powe upplie, the complex dynamic of ac machine, machine paamete vaiation, and the difficultie of poceing feedback ignal in the peence of hamonic. The objective of thi chapte i to illutate the indiect vecto contol technique fo induction geneato in wind powe application. Page 52

62 Chapte3 3.2 INDIRECT VECTOR CONTRO OF INDUCTION GENERATOR The indiect vecto contol method i eentially the ame a the diect vecto contol, except that the oto angle θ e i geneated in an indiect manne (etimation) uing the meaued peed ω and the lip peed ω l. Figue 3.1 explain the fundamental pinciple of indiect vecto contol with the help of phao diagam. The d q axe ae fixed on the tato, but the d q axe, which ae fixed on the oto, ae moving at peed ω a hown. Synchonouly otating axe e e d q ae otating ahead of the d q axe by the poitive lip angle θ l coeponding to lip fequencyω l. Since the oto pole i diected on the axi andω = ω + ω, o we have e l e d θ e = ω e dt = ( ω + ω l ) dt = θ + θ ( 3.1) l The phao diagam ugget that fo decoupling contol, the tato flux component of cuent i d hould be aligned on the e q axi a hown in Figue 3.1. e d axi, and the toque component of cuent i q hould be on the e q θ i q Λ I ψq q i d θ e θ l id iq Ψ d Λ = Ψ ω l ψ d θ e d ω e d d ω Figue 3.1 Phao diagam explaining indiect vecto contol Page 53

63 Chapte3 The oto cicuit equation can be witten a dψ dt d dψ dt q + Rid (ωe ω )Ψ q + Riq + (ωe ω )Ψ d = = ( 3.2) ( 3.3) By eliminating oto cuent which ae inacceible, we have Fo decoupling contol dψ dt d dψ dt q R m + Ψ d Rid ωlψ q R m + Ψ q Riq + ωlψ d = = ( 3.4) ( 3.5) Ψ q = ( 3.6) and, dψq dt = ( 3.7) So we have R dψ dt + ψ = m i d ( 3.8) And the lip fequency fo decoupling contol i given a: R R i m q ω l = iq = ( 3.9) ψ id If the oto flux Ψˆ = contant, we have ˆ i (3.1 ) Ψ = The block diagam of indiect vecto contol cheme fo induction machine dive i hown in m d Page 54

64 Chapte3 Figue 3.2. The PWM invete ae not modelled and imulated in thi wok. The invete ae conideed to have intantaneou epone with fixed gain. The peed and cuent contolle may be PI contolle, Fuzzy contolle o any contolle which i ued to impove the tanient a well a teady tate pefomance of the induction machine dive. The imulation eult of thi dive ytem with PI- contolle i dicued in thi chapte. The pefomance compaion of the dive ytem incopoating diffeent contolle i done in the next chapte. ( Chapte-5.) Figue 3.2 Block diagam of indiect vecto contolled induction geneato ytem In the above given cheme the whole contol tuctue conit of a peed contol loop and two cuent contol loop. In the peed contol loop the oto peed i compaed with the efeence peed and the peed eo i then fed to the PI-contolle (PI-1) which geneate the efeence cuent command i q *. Then in the cuent contol loop the cuent eo i geneated by compaing the cuent i q with it efeence value and the eo i then given to a Page 55

65 Chapte3 PI contolle (PI-3). The output of PI-3 afte CEMF compenation give the efeence quadatue axi voltage command v * q. Similaly fo the diect axi cuent contol loop the efeence value fo oto flux i geneated fom the oto peed ignal though a flux limite. Accoding to equation (3.1) we get the efeence command i * d. The diect axi cuent eo i geneated by compaing i d with it efeence value and the eo i then fed to a PI contolle (PI-2). The output of contolle PI-2 afte CEMF compenation give the efeence diect axi voltage command V * d. In thi contol cheme the contol loop coniting of PI-1 and PI-3 contol the active powe of the induction geneato whee a the contol loop coniting of PI-2 contol the eactive powe flowing to the induction geneato. 3.3 SIMUATION RESUTS AND DISCUSSION The dive ytem i imulated with PI contolle with diffeent opeating condition uch a tep change in the efeence peed and tep change in tubine toque and ome ample eult ae peented in the following ection STEP CHANGE IN TURBINE TORQUE A tep change in command fo tubine toque fom 1 Nm to 15 Nm i given at t = 2.5 which continue fo.5 and again etun to the peviou value. The electomagnetic toque epone of the induction geneato with PI contolle i hown in Figue 3.3. With PI contol it take appoximately.3 to achieve teady tate which can be een clealy fom Figue 3.3. Fom Figue 3.3 it can be een that thee i an ovehoot of 4% which i within the allowable ange. Page 56

66 Chapte Toque in Nm Time in Second Figue 3.3 Electomagnetic toque epone Figue 3.4 how the peed epone of the induction geneato duing change in the tubine toque. Fom thi figue it can be obeved that duing the pime move toque change even if the efeence peed command i 188 pm, the actual peed change fo a tanient peiod and then ettle to 188 pm again efeence peed actual peed 1884 peed in pm Time in Second Figue 3.4 Speed epone Page 57

67 Chapte3 The active and eactive powe epone ae given in Figue 3.5. In the Figue 3.6 the diect and quadatue axi cuent epone ae given. Fom Figue 3.6 it i clea that due to change in tubine toque the quadatue axi cuent o the toque component of cuent change wheea the flux component o the diect axi cuent almot emain unchanged, which i due to the effect of vecto contol tategy. The oto flux ψ, and flux component of tato cuent i d, ae maintained contant though vecto contol. A the peed inceae tempoaily, due to the inceae in tubine toque, both geneated voltage V ph, and fequency f, inceae by the ame facto. Thu eactive powe, which i given by V 2 X m, inceae by the ame facto. The magnitude of the active powe inceae, a the input powe inceae. activepowe and eactive powe active powe eactive powe Time in Second Figue 3.5 Active and eactive powe epone Page 58

68 Chapte3 1 5 id iq id and iq in ampee Time in Second Figue 3.6 Diect and quadatue axi cuent epone The powe facto epone i given in Figue 3.7, which how that a the tubine toque change fom 1 Nm to 15 Nm the powe facto inceae fom.342 to.42. Figue 3.8 how the geneated phae cuent epone powe facto Time in Second Figue 3.7 Powe facto Page 59

69 Chapte ia in ampee Time in Second Figue 3.8 Phae cuent STEP CHANGE IN REFERENCE SPEED COMMAND The pefomance of the dive ytem i again evaluated by ubjecting the ytem to a tep change in the efeence peed. A tep deceae of 2 pm, fom 188 pm to 168 pm i given to the efeence peed and the peed epone of the vecto contolled induction geneato i given in Figue 3.9. Figue 3.1 how the toque epone of the induction geneato. A thee i no change in the input toque, the electomagnetic toque of the machine change fo a tanient peiod and then etun to the initial value. Page 6

70 Chapte efeence peed actual peed 185 Speed in RPM Time in Second Figue 3.9 Speed epone 1 5 Toque in Nm Time in Second Figue 3.1 Electomagnetic toque epone Page 61

71 Chapte3 active powe and eactive powe 1.5 x active powe eactive powe Time in Second Time in Second Figue 3.11 Active and eactive powe epone 4 2 Id iq id and iq in ampee Time in Second Figue 3.12 Diect and quadatue axi cuent epone Page 62

72 Chapte3 Figue 3.11 how the active and eactive powe epone of the induction geneato. In thi figue it can be een that the active powe i educed with the eduction in peed due to the fact that the powe input to the machine i educed. The Figue 3.12 how the diect and quadatue axi cuent epone of the machine when a change in efeence peed command i given. 3.4 CONCUSION Thu with indiect vecto contol uing PI contolle the pefomance of the wind enegy conveion ytem uing induction geneato i impoved. The induction machine how a dc machine like pefomance due to the indiect vecto contol. The tanient a well a the teady tate pefomance of the dive ytem ae impoved. The active powe, eactive powe and line cuent value change fo a vey hot tanient time o ele emain contant thu impoving the tability of the ytem. Page 63

73 Chapte-4 Chapte 4 Pefomance impovement of field oiented induction geneato uing moden contolle 4.1 INTRODUCTION In the peviou ection we have tudied the pefomance of a field oiented induction geneato ued fo wind powe application. The vecto contol cheme in the peviou ection wa done employing PI contolle due to which the pefomance of the machine in tanient peiod wa impoved but could not be made optimum. In thi ection ome advanced contolle will be employed in place of the PI contolle to futhe impove the tanient pefomance of the induction geneato ytem. In thi ection fit we will tudy the induction geneato ytem uing fuzzy contolle. Then a elf tuned fuzzy contolle will be developed fo the induction geneato ytem. Then the pefomance of the induction geneato ytem employing a hybid contolle will be tudied and the pefomance of each contolle will be compaed. Page 64

74 Chapte FUZZY CONTROER INTRODUCTION In 1965, otfi A. Zadeh of the Univeity of Califonia at Bekeley publihed "Fuzzy Set," which laid out the mathematic of fuzzy et theoy and, by extenion, fuzzy logic. Zadeh had obeved that conventional compute logic couldn't manipulate data that epeented ubjective o vague idea, o he ceated fuzzy logic to allow compute to detemine the ditinction among data with hade of gay, imila to the poce of human eaoning. Fuzzy logic, a it name ugget, i the logic undelying mode of eaoning which ae appoximate athe than exact. The impotance of fuzzy logic deive fom the fact that mot mode of human eaoning and epecially common ene eaoning ae appoximate in natue. In doing o, the fuzzy logic appoach allow the deigne to handle efficiently vey complex cloed-loop contol poblem. Thee ae many atificial intelligence technique that have been employed in moden powe ytem, but fuzzy logic ha emeged a the poweful tool fo olving challenging poblem. A compaed to the conventional PI, PID contolle, and thei adaptive veion, the FC ha ome advantage uch a: 1) it doe not need any exact ytem mathematical model. 2) it can handle nonlineaity of abitay complexity. 3) it i baed on the linguitic ule with an IF-THEN geneal tuctue, which i the bai of human logic FUZZY SETS Fuzzy et, a the name implie, i a et without a cip bounday. The tanition fom belong to a et to not belong to a et i gadual, and thi mooth tanition i chaacteized by membehip function. The fuzzy et theoy i baed on fuzzy logic, whee a paticula object Page 65

75 Chapte-4 ha a degee of membehip in a given et that may be anywhee in the ange of to 1. On the othe hand, claical et theoy i baed on Boolean logic, whee a paticula object o vaiable i eithe a membe of a given et (logic 1), o it i not (logic ) MEMBERSHIP FUNCTIONS A membehip function i a cuve that define how the value of a fuzzy vaiable in a cetain egion ae mapped to a membehip value µ (o degee of membehip) between and 1. If X i a collection of object denoted geneically by x, then a fuzzy et A in X i defined a a et of odeed pai: A = {(x, µ A (x))/ x Є X }, (4.1) whee µ A (x) i called the membehip function fo the et A. Thee exit diffeent hape of membehip function. The hape could be tiangula, tapezoidal, cuved o thei vaiation. The vaiou type of membehip function ae given below Tiangula Membehip Function A tiangula Membehip Function i pecified by thee paamete {a, b, c} a follow:, x a. x a, a x b. tiagle( x ; a, b, c) = b a (4.2) c x, b x c. c b, c x. Fo example the tiangula membehip function tiangle (x; 3, 5.8, 8.1) can be illutated a hown in Figue 4.1. Page 66

76 Chapte-4 Fig 4.1 Tiangula Membehip Function Tapezoidal Membehip Function A tapezoidal membehip function i pecified by fou paamete {a, b, c, d}:, x a. x a, a x b. b a tapezoid( x ; a, b, c, d) = 1, b x c. (4.3) d x, c x d. d c, d x. Fo example the tapezoidal membehip function tapezoid (x; 4, 5, 7, 8 ) can be illutated a hown in Figue 4.2. Figue 4.2 Tapezoidal Membehip Function In eal time implementation, both the tiangle membehip function and tapezoidal membehip function have been ued extenively due to thei imple fomula and computational efficiency. Thee two membehip function can have ymmetical o unymmetical hape. Page 67

77 Chapte Gauian Membehip Function A Gauian membehip function i pecified by two paamete {c, σ}: 1 2 x c gauian ( ;, ) 2 x c σ = e σ (4.4) A Gauian membehip function i detemined completely by c and σ ; c epeent the membehip function cente and σ detemine the membehip function width. Figue 4.3 plot a Gauian membehip function defined by gauian(x; 5, 2). Figue 4.3 Gauian Membehip Function Genealized bell Membehip Function A genealized bell membehip function i pecified by thee paamete {a, b, c}: 1 bell ( x; a, b, c) = (4.5) 2b x c 1 + a whee the paamete b i uually poitive. If b i negative, the hape of thi membehip function become an upide-down bell. Figue 4.4 plot a Genealized bell membehip function defined by bell(x; 3,.4, 5). Page 68

78 Chapte-4 Figue 4.4 Genealized bell Membehip Function Sigmoidal Membehip Function A igmoidal membehip function i defined by: 1 ig( x; a, c) = 1+ exp (4.6) [ a ( x c) ] whee a contol the lope at the coove point x=c. Depending on the ign of the paamete a, a igmoidal membehip function i inheently open ight o left. Figue 4.5 plot a Sigmoidal membehip function defined by ig(x; 1, -5) FUZZY SYSTEMS Figue 4.5 Sigmoidal Membehip Function The fuzzy infeence ytem o fuzzy ytem i a popula computing famewok baed on the concept of fuzzy et theoy, fuzzy if-then ule, and fuzzy eaoning. The fuzzy infeence ytem baically conit of a fomulation of the mapping fom a given input et to an output et Page 69

79 Chapte-4 uing F a hown in Figue 4.6. The mapping poce povide the bai fom which the infeence o concluion can be made. The baic tuctue of fuzzy infeence ytem conit of thee conceptual component: a ule bae, which contain a election of fuzzy ule; a data bae, which define the membehip function ued in the fuzzy ule; and a eaoning mechanim which pefom the infeence pocedue upon the ule and given fact to deive a eaonable output o concluion. Figue 4.6 Fuzzy Infeence Sytem The baic infeence poce conit of the following five tep: Step 1: Fuzzification of input vaiable Step 2: Application of fuzzy opeato (AND, OR, NOT) in the IF (antecedent) pat of the ule. Step 3: Implication fom the antecedent to the conequent THEN pat of the ule Step 4: Aggegation of the conequent aco the ule Step 5: Defuzzification Implication Method Thee ae numbe of implication method to fuzzy logic but only two widely ued method ae dicued hee. Thoe ae Mamdani type fuzzy model and Sugeno type fuzzy model. Page 7

80 Chapte Mamdani fuzzy model Mamdani fuzzy ule fo a fuzzy contolle involving thee input vaiable and two output vaiable can be decibed a follow: IF x 1 i A AND x 2 i B AND x 3 i C THEN z 1 i D, z 2 i E whee x 1, x 2, and x 3 ae input vaiable (e.g., eo, it fit deivative and it econd deivative), and z 1 and z 2 ae output vaiable. In theoy, thee vaiable can be eithe continuou o dicete; pactically peaking, they hould be dicete becaue vitually all fuzzy contolle and model ae implemented uing digital compute. A, B, C, D and E ae fuzzy et. "IF x 1 i A AND x 2 i B AND x 3 i C" i called the ule antecedent, wheea the emaining pat i named the ule conequent. The tuctue of Mamdani fuzzy ule fo fuzzy modelling i the ame. The vaiable involved, howeve, ae diffeent. An example of a Mamdani fuzzy ule fo fuzzy modelling i: IF y(t) i A AND y(t - 1) i B AND y(t - 2) i C AND u(t) i D AND u(t - 1) i E THEN y(t + 1) i F whee A, B, C, D, E, and F ae fuzzy et, y(t), y(t - 1), and y(t - 2) ae the output of the ytem to be modelled at ampling time t,t-1and t -2, epectively. And, u(t) and u(t - 1) ae ytem input at time t and t - 1, epectively; y(t+ 1) i ytem output at the next ampling time, t + 1. Obviouly, a geneal Mamdani fuzzy ule, fo eithe fuzzy contol o fuzzy modelling, can be expeed a IF x 1 i A 1 AND x 2 i A 2 AND... AND x k i A k THEN z 1 i B 1, z 2 i B 2..., z m i B m whee x i i the input vaiable, i=1, 2,..., k and z j i the output vaiable, j=1, 2,...,m. A k i the input fuzzy et and B m i the output fuzzy et. Page 71

81 Chapte Sugeno fuzzy model The Sugeno fuzzy model o TSK fuzzy model wa popoed by Takagi, Sugeno, and Kang and wa intoduced in1985. A typical fuzzy ule in a Sugeno fuzzy model ha the fom If x i A and y i B then z = f ( x, y), whee A and B ae fuzzy et in the antecedent, while z = f ( x, y) i a cip function in the conequent. Uually z = f ( x, y) i a polynomial in the input vaiable x and y, but it can be any function a long a it can appopiately decibe the output of the model within the fuzzy egion pecified by the antecedent of the ule. When z = f ( x, y) i a fit-ode polynomial, the eulting fuzzy infeence ytem i called a fit-ode Sugeno fuzzy model. When f i a contant, we then have a zeo-ode Sugeno fuzzy model Defuzzification Method Defuzzification efe to the way a cip value i extacted fom a fuzzy et a a epeentative value. Seveal method ae available fo defuzzification. Hee, a few of the widely ued method namely centoid method, cente of um and mean of maximum ae dicued Centoid Method Centoid method i alo known a cente of gavity method, it obtain the cente of aea z * occupied by the fuzzy et A of univee of dicoue Z. It i given by the expeion z = Z µ ( z) z dz Z A µ ( z) dz A (4.7) fo a continuou membehip function, and Page 72

82 Chapte-4 z = n i= 1 n i= 1 z µ ( z ) i i i µ ( z ) (4.8) fo a dicete membehip function. Whee µ (z A ) i the aggegated output MF. Thi i the mot widely adopted defuzzification tategy, which i eminicent of the calculation of expected value of pobability ditibution Cente of Sum (COS) Method In the centoid method, the ovelapping aea i counted once wheea in cente of um, the ovelapping aea i counted twice. COS build the eultant membehip function by taking the algebaic um of output fom each of the contibuting fuzzy et A 1, A 2, A 3...,etc. The defuzzified value z * i given by z * N n zi i= 1 k= 1 = N n i= 1 k= 1 µ µ A k A k ( z ) i i ( z ) (4.9) whee n i the numbe of fuzzy et and N i the numbe of fuzzy vaiable Mean of Maxima (MOM) Defuzzification MOM i the aveage of the maximizing z * at which the MF each maximum µ *. In ymbol, z * = zi zi M M (4.1) whee M ={ z µ z ) i the height of the fuzzy et}and M i the cadinality of the et M. i ( i Page 73

83 Chapte DESIGN OF FUZZY OGIC CONTROER The baic tuctue of the fuzzy logic contolle i given in Figue 4.7, whee the input to the fuzzy logic contolle ae the nomalized value of eo e and change of eo ce. Nomalization i done to limit the univee of dicoue of the input between -1 to 1 uch that the contolle can be uccefully opeated within a wide ange of input vaiation. Hee K e and K ce ae the nomalization facto fo eo input and change of eo input epectively. Fo thi fuzzy logic contolle deign, the nomalization facto ae taken a contant. The output of the fuzzy logic contolle i then multiplied with a gain K o to give the appopiate contol ignal U. The output gain i alo taken a a contant fo thi fuzzy logic contolle. K e i taken to be the ynchonou peed becaue when the machine i ued a a geneato the lip emain below 8% (-ve). So fo any vaiation in efeence peed the peed eo emain below unity. Similaly K ce i choen to be the maximum value of change that can occu in peed eo. K ce i choen by tial and eo method. Baically, the fuzzy logic contolle conit of fou block i.e. fuzzification, fuzzy infeencing engine, knowledgee bae and a defuzzification block. Figue 4.7 Stuctue of fuzzy logic contolle Page 74

84 Chapte Input/output Vaiable The deign tat with aigning the mapped vaiable Input/output of the FC. In thi wok, the fit contolle to be deigned i the fuzzy logic contolle ued fo peed contol in the active powe contol loop. The fit input vaiable to the peed contolle FC-1 i the peed eo e ω and the econd i the change in the peed eo ce ω at the k th ampling time kt. The two input vaiable e ω (kt ) and ce ω (kt ) ae calculated at evey ampling time a: e ( kt ω * ) = ω ( kt ) ω ( kt ) (4.11) ceω ( kt ) = eω ( kt ) eω (( k 1) t ) (4.12) whee ω (kt ) i the actual oto peed, ω * (kt ) i the efeence peed and e ω ((k-1)t ) i the value of eo at a peviou ampling time. The output vaiable of FC-1 i the efeence value of toque component of cuent i * q. Next contolle to be deigned i the cuent contolle in the active powe contol loop. The cuent contolle FC-3 take the nomalized value of eo in i q and the change of eo in i q a input. The output of the contolle afte gain multiplication and CEMF compenation give the quadatue axi contol voltage V q * which contol the active powe of the induction geneato. Page 75

85 Chapte-4 Figue 4.8 Contol cheme uing fuzzy logic contolle Afte the deign of the FC in the active powe contol loop, come the deign of the FC in the eactive powe contol loop. The efeence flux ignal i geneated fom the peed command though a function geneato implementing flux weakening contolle. The efeence flux i then divided by m, the mutual inductance of the induction geneato to get the efeence command fo the flux component of cuent i * d. FC-2, the cuent contolle in the eactive powe contol loop i then fed with the nomalized value of eo in i d and the change of eo in i d a the input. The output of the contolle FC-2 afte gain multiplication and CEMF compenation give the diect axi contol voltage V d * which contol the eactive powe of the induction geneato. The whole contol cheme uing fuzzy logic contolle i given in Figue 4.8. Page 76

86 Chapte-4 The input eo membehip function ae hown in Figue 4.9. The input eo fuzzy et ue both tiangula and tapezoidal membehip fuction, which ae found to be optimum. Tiangula membehip function a hown in Figue 4.1 ae ued fo change of eo input. The output membehip function ae hown in Figue All the membehip function ae choen to be tiangula o tapizoidal in natue to educe the computational buden on the compute and to make the contolle moe uitable fo eal time application. The output membehip function ae choen by a tial and eo bai uch that the contolle give optimum eult i.e. fate epone with low teady tate eo. Fo thi eaon ome unymety can be een in the output membehip function which i clea fom Figue It can be een that the membehip function ae cowded towad zeo which which i done to make the teady tate eo zeo. Thi alo inceae the peed of epone of the ytem. Figue 4.9 Membehip function fo input vaiable e Figue 4.1 Membehip function fo input vaiable ce Figue Membehip function fo output vaiable Page 77

87 Chapte Fuzzification In thi tage the cip vaiable of the input e and ce ae conveted into fuzzy vaiable that can be identified by the level of membehip in the fuzzy et. Each fuzzy vaiable i a membe of the ubet with a degee of membehip µ vaying between (non-membe) to 1. The fuzzy et fo eo input ae defined a z = Zeo, pl = Poitive low, ph = Poitive high, nl =Negative low, nh =Negative high. The fuzzy et fo change of eo input ae defined a ne = Negative, z = Zeo and p = Poitive. The output fuzzy et ae given a nh = Negative high, nl = Negative low, nc= No change, pl= Poitive low, pm= Poitive medium and ph= Poitive high. The univee of dicoue of all the vaiable, coveing the whole egion, i expeed in pe unit value. All membehip function have aymmetical hape with moe cowding nea the oigin. Thi pemit highe peciion at teady tate Knowledge Bae and Infeencing Knowledge bae involve defining the ule epeented a IF-THEN ule tatement govening the elationhip between input and output vaiable in tem of membehip function. In thi tage the input vaiable e and ce ae poceed by the infeence engine that execute 5 3 ule epeented in ule Table 4.1. A typical ule can be witten a follow. If e i a k and ce i b k then output i c k whee a k, b k, c k ae the label of linguitic vaiable of eo (e), change of eo (ce) and output (U) epectively. Infeencing tage alo include application of fuzzy opeato AND, OR, NOT, Page 78

88 Chapte-4 implication and aggegation. By definition of AND, evaluation of ule eult in a minimum of µ ak (x), µ bk (x) allocated to µ ck (x). Table Defuzzification In defuzzification tage the fuzzy vaiable ae conveted into a cip vaiable. Thi tage intoduce diffeent infeence method that can be ued to poduce the fuzzy et value fo the output fuzzy vaiable U. In thi, the cente of gavity (COA) o centoid method i ued to calculate the final fuzzy value. Defuzzification uing COA method mean that the cip outpu of U i obtained by uing the cente of gavity, in which the cip U vaiable i taken to be the geometic cente of the output fuzzy vaiable value µ out (U) aea, whee µ out (U) i fomed by taking the union of all the contibution of ule with the degee of fulfilment geate than. Then the COA expeion with a dicetized univee of dicoue can be witten a follow: U * n k = 1 = n U k = 1 k µ µ out out ( U ( U k k ) ) (4.13) Page 79

89 Chapte SEF TUNED FUZZY OGIC CONTROER INTRODUCTION Recently many ucceful application of fuzzy contol have been epoted in the field of powe ytem and electic dive. The pefomance of a contolle i cloely elated to it tuning. If the tuning of the contolle i optimum then the contolle will give bet eult. Since the well known fact emain that the tuning of a fuzzy contolle i moe difficult than tuning a conventional contolle. Mot of the time the tuning of the fuzzy contolle i done on the bai of hit and tial and ae abitaily choen. But in vey ae cae the tuning i optimum. Many eeache have invetigated diffeent method of tuning a fuzzy contolle. The optimum value of a contolle alway depend upon the pecific model of the poce that ha to be contolled. So tuning of the contolle mut be done baed on the knowledge of the contolled plant. In mot of the cae the tuning paamete ae taken a contant, due to which the contol action emain the ame in fo any nonlineaity uch a dead time o paamete vaiation. Due to which depite of optimum tuning paamete the contolle fail to give optimum eult. To avoid thi kind of dawback a elf tuned fuzzy logic contolle cheme ha been developed in thi wok. Befoe poceeding to the elf tuning poce it i impotant to have an idea about the diffeent tuning paamete and thei effect on the pefomance of the contolle TUNING PROCEDURE Tuning paamete et u conide a fuzzy logic contolle with tiangula membehip function. The paamete of the fuzzy logic contolle that can be tuned ae given below. Scaling facto of IF/ THEN pat fuzzy vaiable: Page 8

90 Chapte-4 We define caling facto a the maximum peak value, which define the univee of dicoue of the fuzzy vaiable. Peak value Peak value i defined a the value at which the membehip function i 1. Rule Width value Width value i given a the inteval fom the peak value to the point at which membehip become Effect of paamete change Hee we conide how each paamete affect the pefomance of a fuzzy contol ytem. Scaling facto: when a caling facto of a fuzzy vaiable i changed, we aume the definition of each membehip function will change by the ame atio. Hence, changing of any caling facto can change the meaning of one pat, i.e., the IF pat o the THEN pat, in any ule. So we can ay that a change of caling facto may affect all of the contol ule in the ule table a hown by the haded aea in Table 4.2 Table 4.2 Effect of change of a caling facto Page 81

91 Chapte-4 Peak value: When peak value i changed the definition of only one fuzzy label i changed. Hence, changing a peak value can affect only the ule which ue the changed fuzzy label. The Table 4.3 how the affected ule when changing a peak value of an IF pat vaiable. Table 4.3 Effect of change of a peak value Rule : When a ule change it affect only the ule involved a hown in the Table 4.4 Table 4.4 Effect of change of a ule Width value: Changing the width value affect the intepolation between two peak value. If the width value ae equal to the inteval between two adjacent peak value, then it output change continuouly and moothly a the input change. But a the width value goe on educing, the degee of cip of the output goe on nceaing. Page 82

92 Chapte SEF TUNED FUZZY OGIC CONTROER DESIGN An FC ha a fixed et of contol ule, uually deived fom expet knowledge. The membehip function (MF ) of the aociated input and output linguitic vaiable ae geneally pedefined on a common univee of dicoue. Fo the ucceful deign of FC pope election of input and output caling facto (SF ) and/o tuning of the othe contolle paamete ae cucial job, which in many cae ae done though tial and eo o baed on ome taining data. Of the vaiou tunable paamete, SF have the highet pioity due to thei global effect on the contol pefomance. Howeve, elative impotance of the input and output SF to the pefomance of a fuzzy logic contol ytem i yet to be fully etablihed. Unlike conventional contol, which i baed on mathematical model of a plant, a FC uually embed the intuition and expeience of a human opeato and ometime thoe of deigne and eeache. While contolling a plant, a killed human opeato manipulate the poce input (i.e., contolle output) baed on the knowledge of eo and change of eo with a view to minimize the eo within the hotet poible time. Fuzzy logic contol i a knowledgebaed ytem. By analogy with the human opeato, the output SF hould be conideed a vey impotant paamete of the FC ince it function i imila to that of the contolle gain. Moeove, it i diectly elated to the tability of the contol ytem. So the output SF hould be detemined vey caefully fo the ucceful implementation of a FC. Hee, we have concentated only on the tuning of output SF, conideing that it i equivalent to the contolle gain. Tuning of the output SF ha been given the highet pioity becaue of it tong influence on the pefomance and tability of the ytem. In thi cheme, the Page 83

93 Chapte-4 FC i tuned on-line (while the contolle i in opeation) by dynamically adjuting it output SF by a gain updating facto α. In thi cheme a tuning FC (TFC) i ued to tune the output gain of the main FC. The input to both the main FC and the TFC ae nomalized value of eo and change of eo. The output of the TFC i the gain updating facto α which ha a value between and 1.When α i multiplied with K o give the output gain of the STFC. The main FC i imila to the FC a dicued in the peviou ubection. The gain tuning mechanim of the STFC i hown in Figue In the TFC tiangula membehip function ae ued fo all input a well a output fuzzy et. With a view to impove the oveall contol pefomance, we ue the ule bae in Table- 4.5 fo computation of α. Figue 4.12 STFC gain tuning cheme Page 84

94 Chapte-4 Some of the impotant conideation that have been taken into account fo detemining the ule ae a follow. 1) To make the contolle poduce a lowe ovehoot and educe the ettling time (but not at the cot of inceaed ie time) the contolle gain i et at a mall value when the eo i big (it may be ve o +ve ), but e and ce ae of oppoite ign. Fo example, If e i poitive big (pb) and ce i negative mall (n) then α i vey mall (v) o if e i negative medium (nm) and ce i poitive medium (pm) then α i mall (). Obeve that when the eo i big but e and ce ae of the ame ign (i.e., the poce i now not only fa away fom the et point but alo it i moving fathe away fom it), the gain hould be made vey lage to pevent fom futhe woening the ituation. Thi ha been ealized by ule of the fom: If e i pb (poitive big) and ce i p (poitive mall) then α i vb (vey big) o If e i nm and ce i nm then α i vb. 2) Depending on the poce tend, thee hould be a wide vaiation of the gain aound the et point (i.e., when e i mall) to avoid lage ovehoot and undehoot. Fo example, ovehoot will be educed by the ule If e i ze (zeo) and ce i nm (negative medium) then α i b (big). Thi ule indicate that the poce ha jut eached the et point, but it i moving away upwad fom the et point apidly. In thi ituation, lage gain will pevent it upwad motion moe eveely eulting in a malle ovehoot. Similaly, a lage undehoot can be avoided uing the ule of the fom: If e i n and ce i p (poitive mall) then α i v (vey mall). Thi type of gain vaiation aound the et point will alo pevent exceive ocillation and a a eult the convegence ate of the poce to the et point will be inceaed. Note that unlike conventional FC, hee the gain of the popoed contolle aound the et point may Page 85

95 Chapte-4 vay conideably depending on the tend of the contolled poce. Such a vaiation futhe jutifie the need fo vaiable caling facto. 3) Pactical pocee o ytem ae often ubjected to load ditubance. A good contolle hould povide egulation againt change in load; in othe wod, it hould bing the ytem to the table tate within a hot time in the event of load ditubance. Thi i accomplihed by making the gain of the contolle a high a poible. Hence, to impove the contol pefomance unde load ditubance, the gain hould be ufficiently lage aound the teady-tate condition. Fo example If e i p and ce i pm then α i b o If e i n and ce i nm then α i b. Note that immediately afte a lage load ditubance e may be mall but ce will be ufficiently lage and they both will be of the ame ign and in that cae, α i needed to be lage to inceae the gain. At teady tate contolle gain hould be vey mall to avoid chatteing poblem aound the et point. Futhe modification of the ule bae fo α may be equied, depending on the type of epone the contol ytem deigne wihe to achieve. It i vey impotant to note that the ule bae fo computation of α will alway be dependent on the choice of the ule bae fo the contolle. Any ignificant change in the contolle ule bae may call fo change in the ule bae fo α accodingly. Page 86

96 Chapte-4 Table 4.5 Rule table The input and output membehip function fo the TFC ae given in Figue 4.13 and Figue 4.14 epectively. Fo deigning of the TFC,.Mamdani type fuzzy infeencing i ued. The value of membehip function, fuzzy et fo input and output vaiable, and the ule ued in the tudy ae choen to be the ame a thoe of a geneal fuzzy contolle. In thi tudy the centoid method of defuzzification i ued. Figue 4.13 Input membehip function fo TFC Page 87

97 Chapte-4 Figue 4.14 Output membehip function fo TFC The whole indiect vecto contol cheme i ame a the cheme in the peviou ubection. The thee fuzzy logic contolle ae eplaced by thee elf tuned fuzzy logic contolle and the pefomance of the ytem i evaluated. Page 88

98 Chapte HYBRID CONTROER INTRODUCTION The cage induction machine i one of the mot obut machine, which i often ued fo wind powe geneation pupoe. Thee ae many technique to contol the peed of the induction machine uch a tato voltage contol and fequency contol etc. Fo achieving vaiable peed opeation, the fequency contol method of the cage machine i the bet method among all the method, of the peed contol. Vecto contol of the cage machine, i conideed a a fat epone and high pefomance method to achieve vaiable peed. In vecto contol method the induction machine can be opeated like a epaately excited compenated DC moto fo high pefomance application. In the lat decade, many cloed loop peed contol technique have been developed to povide high level pefomance. Howeve, the deied dive pecification ae till to be pefectly atified and / o thei algoithm ae too complex. Howeve in vecto contol of cage induction machine the contolle play the mot ignificant ole. The pefomance of the dive i detemined by the accuacy and obutne of the contolle. The mot common and widely ued contolle i the PI contolle. The PI contolle give vey accuate pefomance i.e. the teady tate eo i vey le and mot of the time zeo teady tate eo can be achieved. With PI contolle the computational time i alo vey le o it i bet uited fo eal time application. At teady tate the noie i alo negligible with PI contolle. But depite of thee advantage the majo dawback of thi type of contolle i that the tanient pefomance of the contolle i poo and the contolle alo ometime uffe fom tability poblem. Depite of pefect tuning the contolle cannot give optimum pefomance due to paamete vaiation of the induction machine. Due to thi fact PI contolle ae not capable of giving high pefomance. Page 89

99 Chapte-4 On the othe hand the fuzzy logic appoach ha got an inceaing inteet and ha found application in many domain of contol poblem. The main featue i the contuction of the fuzzy logic contolle (FC), which utilize the linguitic impecie knowledge of human expet. The main advantage of fuzzy logic contol method a compaed to conventional contol technique eide in fact that no mathematical modelling i equied fo contolle deign and alo it doe not uffe fom the tability poblem. In vaiable peed contol poblem, fuzzy logic can be conideed a an altenative appoach to conventional contol. It ha been ecently demontated that dynamic pefomance of electic dive a well a obutne with egad to paamete vaiation can be impoved by adapting the non linea peed contol technique. Fuzzy logic i a non linea contol and it allow the deign of optimized non linea contolle to impove the dynamic pefomance of the conventional contolle. The fuzzy logic contolle ha vey good tanient pefomance but intoduce noie at the et efeence peed and how teady tate eo duing load. The computational buden of thi type of contolle i alo vey high. In thi ection the application of hybid contol to an indiect vecto contolled cage induction machine dive i invetigated DESIGN PRINCIPES FOR HYBRID CONTROER The hybid contolle i the combination of PI contolle and elf tuned fuzzy contolle. The contol law witche between the elf tuned fuzzy contolle and the PI contol. The hybid contolle i deigned to have all the advantage of PI contolle a well a the fuzzy contolle. The hybid contolle i table and it alo give accuate pefomance at teady tate. Thi contolle ha le computational buden o it i alo well uited fo eal time application. The tanient pefomance i alo vey good which make it a vey uitable contolle fo high pefomance dive. Page 9

100 Chapte Deign of the PI contolle The mot popula peed contol ued in conventional machine contol i PI contol becaue the PI contol i imple and accuate. A the computational buden fo thi contolle i le it i eliable to implement. The PI contolle ued hee i a conventional contolle given by the equation U ( t) = K * e( t) + K * e( t dt p i ) Whee K p and K i ae the popotional and integal gain epectively. Thee gain ae detemined by tial and eo poce to give the bet pefomance. Howeve, ince the vaiation and high uncetainty of induction machine intenal paamete, the tuning of PI contol gain become a challenging poblem. Thi poblem again become moe eiou when the ytem tate ae fa fom thei teady tate value. At thi condition the PI contolle often how tability poblem. Again the tanient pefomance of thi type of contolle i alo not up to mak. Due to thee daw back the PI contolle i not conideed a a obut contolle and i not uitable fo vey high pefomance dive application Deign of the SEF TUNED FUZZY contolle The elf tuned fuzzy contolle deign i decibed in the peviou ubection. Thi contolle doen t have any tability poblem. Due to thi advantage the elf tuned fuzzy contolle i made active when the ytem tate ae fa fom thei teady tate value. Thi contolle i obut and give appeciable pefomance duing paamete vaiation. But duing load change the contolle intoduce ome teady tate eo and with thi contolle ome noie i alo intoduced duing teady tate. The computational buden i alo vey high in thi contolle o it i not well uited fo eal time application. Page 91

101 Chapte Deign of the HYBRID contolle Thi deign appoach combine both elf tuned fuzzy contol and a PI contol into an integated one. The contol law witche between the elf tuned fuzzy contol and the PI contol. It i impotant to know the witch condition between both. The idea i a follow. When the ytem tate ae fa fom thei teady tate value, the contolle ued i the elf tuned fuzzy contolle. Thi elf tuned fuzzy contolle dive the ytem tate towad thei teady tate, even unde unknown ytem uncetaintie. When the ytem tate ae about to appoach thei teady tate, the PI contolle tat to wok and enue that the ytem tate eventually each the equilibium point unde the ytem paametic vaiation and ditubance, a illutated in Figue Figue 4.15 Pinciple of hybid contolle The output Y of the induction geneato i compaed with the efeence input R and the eo e i fed to the block which decide the witching logic a hown in Figue The witching logic i developed on the fact that when the ytem tate ae fa fom thei teady Page 92

102 Chapte-4 tate value they may caue intability with PI contolle, o in that condition the elf tuned fuzzy logic contolle i made on which dive the ytem towad teady tate. When the ytem come to the ange whee PI contolle i table the witch poition i changed to PI contolle which take the ytem to teady tate. The elf tuned fuzzy logic contolle ha a good tanient pefomance o it dive the ytem tate quickly towad teady tate, o the tanient time i educed, enhancing the tability of the ytem. On the othe hand duing low eo value the PI contolle dive the ytem to teady tate giving zeo teady tate eo and minimum noie at teady tate. A the PI contolle i active thoughout the teady tate the computational buden i alo educed which make the contolle uitable fo eal time application. Figue 4.16 Block diagam of hybid contolle Figue 4.17.how the witching between the two contolle. The pink aea how the woking egion of the PI contolle whee the yellow aea i the woking egion of the elf tuned fuzzy logic contolle. The elf tuned fuzzy logic contolle wok till 2.55 econd and afte 2.55 econd the PI contolle come into action and the peed eache teady tate at 2.57 econd. Page 93

103 Chapte-4 Figue Woking egion of PI contolle and SEF TUNED FUZZY OGIC contolle The pefomance of the hybid contolle i teted by uing it in the indiect vecto contol cheme of induction geneato which i ame a the cheme in the peviou ubection 4.2. The thee fuzzy logic contolle ae eplaced by thee hybid contolle and the pefomance of the ytem i evaluated. Page 94

104 Chapte RESUTS AND DISCUSSION SIMUATIONS WITH A STEP CHANGE IN TURBINE TORQUE Initially the tubine toque i et at 1 Nm. A tep incement of 5Nm in tubine toque i given at 2.5. At 3 the tubine toque again come to 1Nm Speed Repone Figue 4.18, 4.19 and 4.2 how the peed epone of the induction geneato with fuzzy contolle, elf tuned fuzzy contolle and hybid contolle epectively. With fuzzy contolle a teady tate eo i intoduced in peed which inceae with the change in the tubine toque. Fom Figue 4.18 it can be een that the teady tate eo with fuzzy contolle i 3 pm, but when the tubine toque i inceaed fom 1Nm to 15Nm the teady tate eo inceae to 8 pm. But the teady tate eo with elf tuned fuzzy contolle i le than that in fuzzy contolle, i.e. the teady tate eo i 1.5 pm fo tubine toque of 1Nm and it inceae to 2.6 pm fo tubine of 15Nm which can be een fom Figue With hybid contolle the teady tate eo i zeo. 189 efeence peed actual peed 1885 peed in pm Time in Second Figue 4.18 Speed epone with fuzzy contolle Page 95

105 Chapte efeence peed actual peed 1884 peed in pm Time in Second Figue 4.19 Speed epone with elf tuned fuzzy contolle 1884 efeence peed actual peed 1882 peed in pm Time in Second Figue 4.2 Speed epone with hybid contolle Toque Repone Figue 4.21, 4.22 and 4.23 how the electomagnetic toque epone of the induction geneato with fuzzy contolle, elf tuned fuzzy contolle and hybid contolle epectively. Fom thee figue it i clea that the epone time i the minimum with the elf tuned fuzzy contolle and Page 96

106 Chapte-4 with the hybid contolle the pefomance i a fate a that with elf tuned fuzzy contolle but the hybid contol ha othe advantage uch that it give a noie fee pefomance and ha much le computational buden then fuzzy and elf tuned fuzzy contolle Toque in Nm Time in Second Figue 4.21 Toque epone with fuzzy contolle Toque in Nm Time in Second Figue 4.22 Toque epone with elf tuned fuzzy contolle Page 97

107 Chapte Toque in Nm Time in Second Figue 4.23 Toque epone with hybid contolle Active and Reactive Powe Repone The active and eactive powe epone fo fuzzy contolle, elf tuned fuzzy contolle and hybid contolle ae given in Figue 4.24, 4.25 and 4.26 epectively. Fom the figue it can be een that when thee i an inceae in the tubine toque at 2.5 econd the active powe inceae in the negative diection. The negative ign i due to the convention that powe fed to the machine i taken a poitive, but in cae of induction geneato active powe i fed to the gid whee a the machine take eactive powe fom the gid. Fo that eaon the active powe i negative whee a the eactive powe i poitive. Due to vecto contol the eactive powe vaiation i vey le a compaed to the active powe vaiation. Fo fuzzy contolle the eactive powe vaie fom 1655 Va to 175 Va giving 5.74% vaiation wheea fo elf tuned fuzzy contolle the eactive powe vaiation i fom 1567 Va to 1615 Va giving 3.6% vaiation. The active powe vaie fom124 Watt to 1834 Watt in cae of both the fuzzy and elf tuned fuzzy contolle. Page 98

108 Chapte eactive powe Time in Second 4 3 eactive powe active powe active and eactive powe Time in Second active powe Time in Second Figue 4.24 Active and eactive powe epone with fuzzy contolle Page 99

109 Chapte eactive powe Time in Second 4 3 active powe eactive powe active and eactive powe Time in Second active powe Time in Second Figue 4.25 Active and eactive powe epone with elf tuned fuzzy contolle Page 1

110 Chapte eactive powe Time in Second 4 3 active powe eactive powe Active and eactive powe Time in Second active powe Time in Second Figue 4.26 Active and eactive powe epone with hybid contolle With hybid contolle the active powe vaie fom 124 Watt to 1834 Watt but the eactive powe i highe than both fuzzy and elf tuned fuzzy contolle. Thi compomie i due Page 11

111 Chapte-4 to the PI contolle pat of the hybid contolle. The eactive powe vaie fom1945 Va to 185 Va. giving 5.13% vaiation. At teady tate both fuzzy and elf tuned fuzzy contolle intoduce noie in active a well a eactive powe which can be clealy een fom Figue 4.24 and The noie content of the elf tuned fuzzy contolle i le in teady tate compaed to the fuzzy contolle, but with hybid contolle thee i no noie content at all in active and eactive powe, which become a tong advantage of the hybid contolle. The ign of change in the eactive powe ae diffeent. With elf tuned fuzzy contolle, the eactive powe emain almot unchanged. With P-I and fuzzy contolle, it inceae. But with hybid contolle (Fig. 4.26) the eactive powe i educed. Thi may be due to the witching back and foth between P-I contolle and the elf tuned fuzzy contolle Cuent Repone In Figue 4.27, 4.28 and 4.29 the vaiation in toque component and flux component of cuent ae hown id iq 1 id and iq in ampee Time in Second Figue 4.27 Diect and quadatue axi cuent epone with fuzzy contolle Page 12

112 Chapte id iq 1 id and iq in ampee Time in Second Figue 4.28 Diect and quadatue axi cuent epone with elf tuned fuzzy contolle 2 15 id iq id and iq in ampee Time in Second Figue 4.29 Diect and quadatue axi cuent epone with hybid contolle Due to vecto contol technique the induction machine how DC machine like pefomance that i toque and flux component of cuent ae independent of each othe. With a vaiation in i d thee i no vaiation in i q and vice vea. Fom the figue it i clea that when thee i vaiation in tubine toque the toque component of cuent i q change but the flux component of cuent i d emain unchanged which give the induction machine decoupled pefomance. Page 13

113 Chapte Powe Facto The powe facto of the induction geneato with fuzzy contolle, elf tuned fuzzy contolle and hybid contolle ae given in Figue 4.3, 4.31 and 4.32, epectively..8 powe facto v time Gaph fowe facto Time in Second Figue 4.3 Powe facto with fuzzy contolle powe facto Time in Second Figue 4.31 Powe facto with elf tuned fuzzy contolle With tubine toque of 15 Nm the powe facto of induction geneato i maximum with elf tuned fuzzy contolle which i.75, with fuzzy contolle it i.726 and with hybid contolle Page 14

114 Chapte-4 the powe facto i.71. Thi i due to the fact that among the thee contolle the eactive powe i maximum with hybid contolle, a dicued above. Thee ae lage tanient at 3 in Fig and Fig. 4.32, with hybid contolle. Thi i due to (i) tep change of tubine toque fom 15 N.m to 1 N.m at that intant, and (ii) the witching back and foth between P-I contolle and the elf tuned fuzzy contolle powe facto Time in Second Phae Cuent Repone Figue 4.32 Powe facto with hybid contolle ia in ampee Time in Second Figue 4.33 Cuent epone with fuzzy contolle Page 15

115 Chapte-4 Figue 4.33, 4.34 and 4.35 how the phae cuent epone of the induction geneato with fuzzy contolle, elf tuned fuzzy contolle and hybid contolle epectively ia in ampee Time in Second Figue 4.34 Cuent epone with elf tuned fuzzy contolle ia in ampee Time in Second Figue 4.35 Cuent epone with hybid contolle Page 16

116 Chapte SIMUATIONS WITH A STEP CHANGE IN REFERENCE SPEED The pefomance of the induction geneato ytem i again evaluated by ubjecting the ytem to a tep change in the efeence peed. A tep deceae of 2 pm, i.e. fom 188 pm to 168 pm i given to the efeence peed and diffeent epone of the vecto contolled induction geneato ae given below Speed Repone Figue 4.36, 4.37 and 4.38 how the peed epone with a tep change in efeence peed. A tep change of 2 pm i given at 2.5 which continue fo.5. The peed epone with diffeent contolle how that the ettling time with fuzzy contolle i maximum which i.12 and minimum with elf tuned fuzzy contolle which i.45, but both the contolle intoduce a teady tate eo in the ytem a hown in the peviou ub ection. With hybid contolle the teady tate eo i zeo but the ettling time i compomied to a mall extent efeence peed actual peed Speed in RPM Time in Second Figue 4.36 Speed epone with fuzzy contolle Page 17

117 Chapte efeence peed actual peed Speed in RPM Time in Second Figue 4.37 Speed epone with elf tuned fuzzy contolle The ettling time with hybid contolle i.65 which i fate than fuzzy contolle and a little bit lowe than the elf tuned fuzzy contolle and can be een fom Figue efeence peed actual peed Speed in RPM Time in Second Figue 4.38 Speed epone with hybid contolle Page 18

118 Chapte Toque Repone The toque epone of the induction geneato ytem with fuzzy, elf tuned fuzzy and hybid contolle ae given in Figue 4.39, 4.4 and 4.41 epectively Toque in Nm Time in Second Figue 4.39 Toque epone with fuzzy contolle 1 5 Toque in Nm Time in Second Figue 4.4 Toque epone with elf tuned fuzzy contolle Page 19

119 Chapte Toque in Nm Time in Second Figue 4.41 Toque epone with hybid contolle Fom the above mentioned figue it can be een that the ettling time i minimum with elf tuned fuzzy contolle and maximum with fuzzy contolle. The ettling time of the ytem with hybid contolle i much le than that with fuzzy contolle but i a bit moe than that with elf tuned fuzzy contolle, due to the peence of the PI contolle in hybid contolle Active and Reactive Powe Repone Figue 4.42, 4.43 and 4.44 how the active and eactive powe epone of the induction geneato ytem with fuzzy contolle, elf tuned fuzzy contolle and hybid contolle epectively, with a tep change in efeence peed. A thee i a eduction in the input powe to the ytem due to the eduction in machine peed, the active powe educe in the teady tate fom 124watt to 11 watt. Page 11

120 Chapte-4 activepowe and eactive powe eactive powe active powe Time in Second Figue 4.42 Active and eactive powe epone with fuzzy contolle activepowe and eactive powe 2 x active powe eactive powe Time in Second Figue 4.43 Active and eactive powe epone with elf tuned fuzzy contolle Page 111

121 Chapte-4 active and eactive powe 2 x active powe eactive powe Time in Second Figue 4.44 Active and eactive powe epone with hybid contolle Cuent Repone Figue 4.45, 4.46 and 4.47 how the diect axi and quadatue axi cuent epone of the induction geneato ytem with fuzzy contolle, elf tuned fuzzy contolle and hybid contolle epectively, with a tep change in efeence peed. It can be een fom the figue that except thee i a change in quadatue axi cuent in the tanient peiod, thee no change in it duing the teady tate. But a the efeence peed command deceae fom 188pm to 168 pm, the diect axi cuent value inceae fom 7.32 ampee to 7.37 ampee. Page 112

122 Chapte id iq id and iq in ampee Time in Second Figue 4.45 Diect and quadatue axi cuent epone with fuzzy contolle 8 6 id iq id and iq in ampee Time in Second Figue 4.46 Diect and quadatue axi cuent epone with elf tuned fuzzy contolle Page 113

123 Chapte id iq 4 id and iq Time in Second Figue 4.47 Diect and quadatue axi cuent epone with hybid contolle 4.6 CONCUSION In the above ection thee diffeent contolle i.e. fuzzy contolle, elf tuned fuzzy contolle and hybid contolle, ae deigned and ued to impove the pefomance of an induction geneato ytem. In thi chapte the pefomance of the ytem i evaluated. we obeved that the fuzzy contolle gave bette tanient pefomance than the PI contolle but in teady tate the fuzzy contolle pefomance wa pooe than the PI contolle, a in the teady tate the fuzzy contolle intoduce ome eo and noie. The elf tuned fuzzy contolle give the fatet tanient epone but it intoduce ome teady tate eo and noie in the ytem which i le than the fuzzy contolle, but it emain to be the main dawback of the elf tuned fuzzy contolle. With hybid contolle the dawback in fuzzy and elf tuned fuzzy contolle wee compenated. The tanient epone of the hybid contolle i a bit lowe than the elf tuned fuzzy contolle but the hybid contolle gave a upeio teady tate epone than the elf tuned fuzzy contolle which make the hybid contolle uitable fo high pefomance contol. Page 114

124 Chapte-5 Chapte 5 Vecto contol of gid ide PWM convete fo powe facto impovement 5.1 INTRODUCTION In the powe poceo block of Figue 3.8 two VSI ae connected in back to back fahion among which the machine ide VSI i ued fo the vecto contol of the induction geneato. It make the output voltage of the induction geneato of vaiable magnitude and vaiable fequency. The line ide convete can be made to wok a a contolled convete with bidiectional powe flow and a a STATCOM capable of woking at unity and leading powe facto. Beide, the magnitude and fequency of the output voltage can be made contant which allow the ytem to be gid connected. Two ditinctive featue in bidge cicuit of Figue 3.8 ae the inductance on the ac ide and a lage capacitance on the dc link. The capacitance i ued to enue faily contant voltage ove a hot peiod of time, iepective of the tanient and the witching the event in the conveto. The phae cicuit inductance i intended to filte out the cuent ipple and ait in the indiect contol poce of the cuent at a choen powe facto. In thi chapte the complete wind powe geneation ytem will be dicued which will include two impotant tategie, which ae Maximum powe point tacking Gid ide PWM invete contol Page 115

125 Chapte MAXIMUM POWER POINT TRACKING A hown in chapte-1 the powe extacted by a wind tubine fo a given wind peed i maximized if C p i maximized. The optimum value of C p, alway occu at a definite value of λ i.e. λ opt, thi mean fo vaying wind peed, the oto peed hould be adjuted to adhee alway to thi value of λ=λ opt fo maximum mechanical powe output fom the tubine. To achieve thi condition, a tategy known a maximum powe point tacking i ued. By uing thi technique the efeence peed command fo the induction geneato i changed uch that the value of λ alway emain at λ opt. Figue 5.1 Maximum powe point tacking tategy Fo a paticula wind velocity, function of maximum powe point tacking algoithm i to each the geneato peed until the ytem ettle down at the maximum powe output condition. A hown in Figue 5.1, fo wind velocity Vw3, the output powe i at point-a if the geneato Page 116

126 Chapte-5 peed i ω 1. The maximum powe point tacking algoithm alte the peed in tep until it eache the value ω 2, whee the output powe i maximum at point-b. If the wind velocity will inceae to Vw1, the outputt powe will jump to point-c, and then maximum powe point tacking algoithm will bing the opeating point to D by eaching the peed to ω 4. Similaly when the wind peed deceae to Vw2, the opeating point again jump to point E. Fom point E the maximum powe point tacking algoithm again dive the opeating point to point F which give the maximum powe at wind peed of Vw2 fo a geneato peed of ω SUPPY SIDE CONVERTER CONTRO With efeence to the ectifie convention and conideing the fundamental fequency component only, the teady-tate ac-ide quantitie ae elated in the manne hown in the Figue 5.2, 5.3 and 5.4. Figue 5.2 Gid ide powe cicuit configuation Fo the ectifie mode of opeation, hown in Figue 5.3, the fundamental fequency component V I at the ac input teminal lag behind the ouce voltage V by an angle δ, and I ha a component in phae with V. In the phao diagam of Figue 5.4, the voltage V I lead V when the ac upply cuent I ha inveting mode of opeation, a component which i an phae oppoition to V, implying the whee the powe flow i fom the dc ide to the ac ide. In eithe Page 117

127 Chapte-5 cae, neglecting the eitancee of the inducto coil, the powe flow though the inducto coil i given by VV P = 3 X I in δ (5.1) Whee δ i known a the load angle and i uppoed to be poitive fo the lagging phae. Figue 5.3 Phao diagam fo ectifie mode of opeation of PWM invete Figue 5.4 Phao diagam fo invete mode of opeation of PWM invete Theefoe, the cuent magnitude, powe tanfe, and the mode of opeation (ectifie/invete) can be contolled by adjuting the magnitude and / o phae (lag o lead) of V I in elation to the ac upply voltage V. Page 118

128 Chapte-5 Fom the phao diagam in Figue 5.3 the in-phae and the quadatue component of the convete ac teminal voltage ae found to be VI coδ = V - RI coϕ XI inϕ (5.2) VI inδ = XI coϕ RI inϕ (5.3) Fo the inveting mode, with the cuent I flowing into the ouce at a powe- facto angle ϕ 1, ϕin equation (5.2) and equation (5.3) i eplaced by (18 - ϕ 1 ). V, R, and X ae obtained fom diect meauement. To opeate the convete at a deied powe facto angle ϕ fo any demand of the cuent I, o powe, equation (5.2) and (5.3) ae ued to povide the value of V I and δ, which decide the magnitude and the phae of the modulating ine wave with efeence to the upply voltage. Invete teminal voltage υ ai, υ bi, and υ ci can be contolled by a vecto contolle fo thei magnitude and equied phae hift fom the upply to meet the equied active and eactive powe. The voltage equation fo the line inducto ae diabc υ abc, = Ri abc + + υabc, I (5.4) dt In the d e -q e efeence fame a hown in Figue 5.5, otating at the upply angula fequency ω e and the d e -axi coinciding with the upply voltage vecto, the voltage equation 5.4, become e e e e e υ = Ri + pi ω i + υ di, (5.5) d d d e q e e e e = Ri + pi + ω i + υ, (5.6) q q e d qi Page 119

129 Chapte-5 Whee q e - axi. e υdi and e υqi Figue 5.5 Angula elationhip ae the component of the invete ac teminal voltage vecto along the d e and Again P = e υ e di d + υ e q i e q (5.7) but, υ e d = 3V (5.8) and e υ q = Fom equation (5.7), the active powe flow i P = υ i d e e d (5.9) Uing equation (5.6) and (5.8) in equation (5.9) fo teady tate opeation, i.e., p = and neglecting R. P = 3 V V ω e e qi (5.1) Page 12

130 Chapte-5 With efeence to the elative poition of the voltage vecto and thei component along the d e - q e, the powe flow given by equation (5.1) become 3V VI P = in δ (5.11) X Again the eactive powe i given by Q υ υ e e e e = qi d di q (5.12) e Since υ q =, fom equation (5.12), the eactive powe flow i Q = υ d i (5.13) e e q The ue of equation (5.5) and (5.8) with voltage vecto component along the d e -q e axe in figue 5.3 give 3V 2 3V VI Q = co δ (5.14) X X The vecto contol cheme to egulate the powe flow i detailed in Figue 5.6. The utility ytem voltage υ abc, i tanfomed into tationay d -q component. A the d e - axi of the ynchonouly otating efeence fame i aligned along the upply voltage vecto, the angula poition of the d e - axi i computed a Vq θe = actan V d (5.15) Page 121

131 Chapte-5 Figue 5.6 Vecto contol cheme fo line ide convete The actual active and eactivee powe, computed by equation (5.9) and (5.13), epectively, ae compaed with the efeence value P * and Q * to geneate the efeence value of the invete teminal voltage e υ di * e and υ * in accodance with equation (5.5) and qi (5.6). P* i the active powe geneated by the induction geneato and the efeence eactive powe Q* i taken a zeo uch that the upply ide powe facto become unity. Actual powe output of the gid ide convete will be le than the powe output of the induction geneato ince the loe of the convete ae to be upplied. Theefoe etting P* equal to output powe of the induction geneato will not be able to keep the dc link voltage contant if thee ae loe taking place in the convete. But fo thi wok the convete ae aumed to be lole o that the powe geneated fom geneato become equal to the powe at the gid ide. So, etting P * equal to the output of the induction geneato will not affect the contol cheme adveely. Cloed loop contol of dc link voltage to geneate P * and i d, and cloed loop contol of i q will be inteeting futue coue of eeach. Page 122

132 Chapte RESUTS AND DISCUSSION In thi ection the wind powe geneation ytem uing induction geneato i imulated and the eult ae peented. The wind powe geneation ytem i imulated with vaying wind velocitie. The maximum powe point tacking algoithm decide the efeence peed of the induction geneato fo extaction of the maximum powe fom the wind. Afte the efeence peed ha been decided vecto contol of the induction geneato i done fo pefomance impovement of the induction geneato. Then the vecto contol of the gid ide convete i done to make the geneated voltage and fequency contant a well a fo powe facto impovement. The compaion of the geneato ide and gid ide paamete ae given below Wind velocity Repone Figue 5.7 how the vaiation in wind velocity a a function of time. Initially the wind peed educe fom 9m/ to 8m/ then emain contant fo 2 and again inceae to 12 m/ and emain contant at that value wind peed in m/ec Time in Second Figue 5.7 Wind velocity a a function of time Page 123

133 Chapte Refeence peed Repone 2 Refeence peed in RPM Time in Second Figue 5.8 Refeence peed of the induction geneato a given by maximum powe point tacking algoithm A the wind velocity vaie, the maximum powe point tacking algoithm come into action and keep tack of the efeence peed of the induction geneato uch that maximum powe can be extacted fom the wind. The effect of maximum powe point tacking technique can be een fom Figue 5.8. The figue how the change in the efeence peed of the induction geneato in accodance with the wind velocity to extact the maximum powe fom the wind Tubine toque Repone The mechanical ytem of a wind tubine intoduce hamonic in the tubine toque which make the tubine toque pulating in natue. The ocillatoy toque of the wind tubine i moe dominant at the fit, econd and fouth hamonic of the fundamental tubine angula velocity. The ocillatoy toque i given a T oc ( Aco ωt + Bco2ωt + C co4ωt ) = T (5.16) m Page 124

134 Chapte-5 The total tubine toque i given a T = T + T (5.17) tubine m oc The vaiation in tubine toque due to the change in wind peed i hown in Figue 5.9.The pulating natue of the tubine toque due to ocillatoy toque can be een in the figue. 9 8 wind peed tubine toque wind peed and tubine toque Time in Second Figue 5.9 Vaiation in tubine toque Electomagnetic toque Repone of induction geneato Toque in Nm Time in Second Figue 5.1 Toque epone of the induction geneato Page 125

135 Chapte-5 The electomagnetic toque epone of the induction geneato i hown in the Figue Diect and quadatue axi cuent epone at geneato and gid teminal geneato end. Figue 5.11 give the diect axi and quadatue axi tato cuent at the induction Geneato ide cuent in ampee id iq Time in Second Figue 5.11 Geneato ide diect and quadatue axi cuent epone 2 15 Id Iq upply ide cuent in ampee Time in Second Figue 5.12 Gid ide diect and quadatue axi cuent epone Page 126

136 Chapte-5 Due to the effect of indiect vecto contol technique the diect axi cuent I d o the flux component of cuent emain contant a the toque component of cuent I q vaie due to the vaiation of tubine toque. The pulation in the electomagnetic toque of the induction geneato ae due to the ocillatoy toque of the wind tubine. The epone of the diect and quadatue axi cuent at the gid ide ae given in Figue Active and eactive powe epone at geneato ide and gid ide Figue 5.13 how the active and eactive powe epone at the induction geneato ide. The figue how that both the active powe and eactive powe at the geneato ide vay a the tubine toque vaie x 14 active powe eactive powe 1 Geneato ide powe Time in Second Figue 5.13 Geneato ide powe epone But due to the vecto contol of the gid ide invete the eactive powe at the gid ide become zeo and only the active powe i tanfeed to the gid which can be een fom Figue Page 127

137 Chapte-5 2 active powe eactive powe Supply ide powe Time in Second Figue 5.14 Gid ide active and eactive powe epone Phae voltage epone at geneato ide and gid ide Geneato ide phae voltage in volt Time in Second Figue 5.15 Geneato ide phae voltage epone Page 128

138 Chapte-5 The epone fo phae voltage at the geneato teminal and gid teminal ae given in Figue 5.15 and 5.16 epectively. It i clea fom the Figue 5.15 that the amplitude and fequency of the geneato ide phae voltage vay with vaiation in tubine toque, which make the induction geneato ytem unuitable fo diect gid connection Supply ide phae voltage in volt Time in Second Figue 5.16 Gid ide phae voltage epone But by vecto contol of the upply ide convete the amplitude and fequency of the gid ide phae voltage can be made contant due to which the ytem become uitable fo gid connection. Figue 5.16 how the contant amplitude and contant fequency output phae voltage of the gid ide convete. Page 129

139 Chapte Phae cuent epone at geneato ide and gid ide Fom Figue 5.17 it i evident that the fequency of geneato ide phae cuent alo vaie with the vaiation in the tubine toque. But fom Figue 5.18 it can be een that due to the vecto contol of the gid ide convete the fequency of the gid ide phae cuent alo become contant. 4 geneato ide line cuent in ampee Time in Second Figue 5.17 Geneato ide phae cuent epone Page 13

140 Chapte Supply ide phae cuent in ampee Time in Second Figue 5.18 Gid ide phae cuent epone Powe facto epone at geneato ide and gid ide The Figue 5.19 how the phae elation of the geneato ide phae voltage and geneato ide phae cuent. It i clea fom the figue that the phae cuent lag behind the phae voltage by an angle geate than 9 degee but le than 18 degee, due to which the active powe become negative i.e. active powe flow fom geneato to gid, but the eactive powe emain poitive and flow fom gid to the induction geneato. So the powe facto at the geneato ide emain le than unity which can be een fom Figue Page 131

141 Chapte-5 geneato ide phae voltage and cuent phae cuent phae voltage Time in Second Figue 5.19 Phae elation between voltage and cuent of geneato ide Gid ide pha e voltage and cuent phae cuent phae voltage Time in Second Figue 5.2 Phae elation between voltage and cuent of gid ide Page 132

142 Chapte-5 The Figue 5.2 how the phae elation of the gid ide phae voltage and gid ide phae cuent. Fom the figue it can be een that the phae cuent and the phae voltage ae at a phae diffeence of exactly 18 degee, due to which the active powe become negative i.e. active powe flow fom geneato to gid, and the eactive powe become zeo. So the powe facto at the gid ide become unity which can be een fom Figue powe facto compaion Gaph powe facto of geneato ide powe facto of upply ide 1.1 powe facto CONCUSION Figue 5.21 Geneato ide and gid ide powe facto In thi chapte the complete evaluation of the induction geneato ytem i done. By utilizing the maximum powe point tacking algoithm maximum powe i extacted fom the wind. The vecto contol of the gid ide convete made it poible to connect the induction geneato ytem diectly with the gid. It alo helped in achieving unity powe facto at the gid ide Time in Second Page 133

143 Chapte-6 Chapte 6 Fabication and teting of contol cicuit fo a bidiectional convete invete et ued in line excited induction geneato 6.1 INTRODUCTION The implementation of PI contol, fuzzy contol o any high pefomance contol equie a complex and fat contolle. A micopoceo/micocontolle/ digital ignal poceo fom an integal pat of uch a contolle. A fat contolle povide a fate ampling ate a needed, to enue table and ucceful contol. PC- baed implementation of the PI contol fo PWM voltage ouce invete-fed induction geneato i conideed hee. The deign and fabication of the contol cicuit fo the bidiectional PWM convete invete et ae decibed in thi ection. The tet eult ae peented and dicued late in thi ection. A chematic block diagam fo the high pefomance contol of induction geneato i hown in Figue 6.1. The digital pat of the contolle involve a Pentium poceo-baed PC houed with modeately piced add-on cad, uch a analog data acquiition cad (PC-28) and analog output cad (PC-726). The diffeent unit of the contol cheme ae: Page 134

144 Chapte-6 The powe electonic convete feeding a vaiable voltage, vaiable fequency upply to the theee phae induction geneato. The bidiectional PWM convete- invete contol cicuit. Meauement and Data acquiition module. VS --- Voltage eno CS --- Cuent eno TWG --- Tiangula wave geneato Figue 6.1 Schematic block diagam fo induction geneato contol 6.2 POWER EECTRONIC CONVERTERS The powe poceo fo the cheme i a thee phae inuoidal pule width modulated bidiectional voltage ouce convete invete (SPWM-VSI) et to connect vaiable voltage, vaiable fequency upply fom the induction geneato to the gid. The expeimental et up fo the dive ue two thee phae Pule Width Modulated (PWM) Voltage Souce Convete (VSC) uing Inulated Gate Bipola Page 135

145 Chapte-6 Tanito (IGBT). The dc input to the invete i obtained fom the thee phae IGBT convete and an auto-tanfome combination. The VSI enable the vaiable voltage, vaiable fequency opeation of the induction geneato. Figue 6.2 how the powe cicuit diagam of the bidiectional convete invete et employing IGBT a the witching device. Two 1 µ F, 5 V electolytic capacito ae connected aco the input of the VSI to filte out the ipple in the dc link voltage. Figue 6.2 Bidiectional convete invete et 6.3 CONTRO CIRCUIT FOR VSI The block diagam of the contol cicuit i hown in Figue 6.3. In thi modulation cheme, the pule width i a inuoidal function of the angula poition at which the paticula pule i geneated. Thi type of modulation i ealized by compaing a modulating ignal temed contol coniting of a inuoidal wave of vaiable amplitude (A) and fequency (f) and a tiangula ignal temed caie of fixed amplitude (A c ) and fequency (f c ). The fequency, f c of the tiangula wave decide the numbe of pule in the output voltage in each half cycle. The vaiou cicuit compiing the contol cicuit ae: Page 136

146 Chapte-6 Tiangula wave geneato cicuit Thee phae efeence ine wave geneato Compaato cicuit ock-out cicuit Ove cuent potection cicuit Gate dive cicuit TWG Compaato ock-out Cicuit Gate Dive Cicuit S 1 D/A V a * D ock-out Cicuit TWG: Tiangula Wave Geneato D: Diable ignal fom the ove cuent potection cicuit Gate Dive Cicuit S 4 Figue. 6.3 Block diagam of the contol cicuit D TRIANGUAR WAVE GENERATOR CIRCUIT A double ided tiangula caie ignal i equied fo modulation. The caie ignal of amplitude, A c A, whee A i the peak of the modulating ignal; and fequency, f c i geneated uing the cicuit hown in Figue 6.4. The caie ignal wavefom i of nealy tiangula hape. The poviion ae made to adjut the amplitude Page 137

147 Chapte-6 and the fequency of the caie ignal o that the invete pefomance i impoved. The poviion fo offet adjutment i alo made. Figue. 6.4 Tiangula wave geneato with offet adjutment cicuit THREE PHASE REFERENCE SINE WAVE GENERATOR The efeence inuoidal ignal i geneated by oftwae uing a Pentium poceo-baed PC. The efeence ignal fo phae-a and phae-b ae geneated with a phae diffeence of 12. The efeence voltage ignal fo phae-c i geneated uing a umming amplifie hown in Figue 6.5, whoe input ae the efeence voltage ignal fo phae-a and phae-b. The potentiomete i povided to adjut the amplitude of the efeence voltage ignal fo phae-c. * V a * V b * V c Figue. 6.5 Summing amplifie cicuit Page 138

148 Chapte COMPARATOR CIRCUIT Figue 6.6 how the compaato cicuit uing T-84. Thee efeence inuoidal wave ae compaed individually with the tiangula wave to output the Sinuoidal Pule Width Modulated (SPWM) ignal a equied. The negative potion i clipped by the diode and then the output i caled to +5 V. Caie wave Modulating wave To lock-out cicuit Figue. 6.6 Compaato, clipping and caling cicuit OCKOUT CIRCUIT Figue 6.7 how the lockout cicuit. The output of the compaato i paed though a hex invete gate (744). The inveted ignal and the non-inveted ignal ae meant fo two complementay IGBT on the ame leg of the invete. Thee two ignal ae paed though R-C diffeentiato and diode cicuit, which give a tigge pule to the monotable multivibato (555) at the negative edge of the ignal. The multivibato cicuit geneate a pule, whoe width i contant depending on the value of the eitance and capacitance at the pin numbe 6, 7 of the 555. The width of thi pule (geneated by 555) i the intelock delay peiod. The intelock delay peiod between a Page 139

149 Chapte-6 pai of witching device (IGBT) in the ame leg i kept at 3 µ ec. Thi delay pule, the ignal fom the compaato, and the Enable/Diable ignal fom the ove cuent potection cicuit ae the thee input to the NOR gate (7427). NOR gate povide the gate pule to the gate dive cicuit of the IGBT. Thee uch cicuit have been fabicated. The timing diagam of the pule geneated by the lockout cicuit ae given in Figue 6.8 and Figue 6.9. Fom Compaato cicuit To Gate Dive cicuit S 1 D (Fom ove cuent potection) S 4 Figue. 6.7 ockout Cicuit Page 14

150 Chapte-6 Figue 1.8 Timing diagam fo output pule of 555 Figue 1.9 Timing diagam fo output pule of lockout cicuit Page 141

151 Chapte OVER CURRENT PROTECTION CIRCUIT Figue 6.1 how the ove cuent potection cicuit. The pinciple of the cicuit i that, when the dc link cuent exceed a paticula et value, a +5 V output (logic high) (S =1, R = ) i obtained. Thi logic high i NOR-ed with the gate pule fom the compaato cicuit, and thu, the gate pule i diabled (D = 1). When the fault i cleaed and dc link cuent i below the et value (S = ); by peing the tat Puh Botton witch (R = 1), the gate pule i enabled (D = ). A long a the fault exit (S = 1, R = ), the gate pule can neve be enabled. S DC link cuent eno R D ED Stat Puh Button witch Figue 6.1 Ove-cuent Potection cicuit GATE DRIVE CIRCUIT The output of the gate pule geneato cicuit i fed to the gate dive cicuit, hown in Figue At the input of the gate dive cicuit, thee i an opto-iolato, MCT-2E, which iolate the gate dive cicuit fom the contol cicuit. The cicuit ue a Page 142

152 Chapte-6 ±15 V powe upply. +15 V i equied to tun on the IGBT and 15 V i equied to tun off the IGBT. Gate dive of the IGBT i upplied by the tanito, S-1. Revee ecovey cuent of the IGBT i taken by the tanito SK-1. Bae dive of both the tanito, S-1 and SK-1 ae upplied by the output tanito of the voltage compaato, M-311. M-311 alo inceae the peed of witching, which othewie would have been eticted by the witching fequency of the opto-iolato, MCT-2E. The output voltage of the complimentay pai of tanito (S-1 and SK-1) i clipped at +15 V and 15 V by a pai of zene diode connected back to back. Six uch cicuit have been fabicated with individual powe upplie fo diving the IGBT of the VSI. 36 V, 5 Hz AC Figue 6.11 IGBT Gate Dive Cicuit Page 143

153 Chapte FABRICATED CIRCUITS AND TEST RESUTS Thi ection include the photo of the diffeent cicuit thoe have been fabicated and the output of each cicuit taken fom the CRO. Figue 6.12 Tiangula wave geneato, umme and compaato cicuit Figue 6.12 i the photo of tiangula wave geneato, umme and compaato cicuit fabicated in one boad. The input to thi cicuit i a inuoidal wave which ha been geneated fom a ignal geneato. The inuoidal ignal i then compaed with a tiangula wave which i geneated by the tiangula wave geneato peent in the fabicated cicuit hown in Figue Figue 6.16 how the wave fom of the tiangula a well a the inuoidal ignal. Figue 6.17 how the PWM ignal geneated by the compaato due to the compaion of the inuoidal and the tiangula ignal. Thi PWM ignal will then be fed to the lock out cicuit to ceate a delay between the gate pule of the witche in the ame leg of the invete. The fabicated lockout cicuit i hown in Figue 6.13 and the output of the lockout cicuit Page 144

154 Chapte-6 i hown in the Figue The output of the lockout cicuit ae pule having amplitude below 4 volt and the pule ae unipola having only poitive magnitude. Figue 6.13 lockout cicuit Figue 6.14 Gate dive cicuit So the output of the lockout cicuit i not uitable fo being ued a gate pule fo the Page 145

155 Chapte-6 IGBT ued in the invete. So the output of the lockout cicuit i fed to the gate dive cicuit to get appopiate gate pule fo the invete. Figue 6.14 how the fabicated gate dive cicuit. The gate dive cicuit poduce bipola gate pule and Figue 6.15 Ove cuent potection cicuit Figue 6.16 Tiangula caie and inuoidal contol ignal Page 146

156 Chapte-6 alo povide iolation between the contol cicuit and the powe cicuit. The gate pule at the output of the gate dive cicuit ae hown in Figue Figue 6.17 Compaato output and it compliment Figue 6.18 Output of the lockout cicuit Page 147

157 Chapte-6 Figue 6.19 Gate pule fo witch S1 and S4 6.5 CONCUSION The vaiou component of the contol cicuit needed fo meauement and data acquiition have been fabicated and individually teted befoe integating into a complete et-up. The tet eult of the contol cicuit wee obtained afte extenive tet in the laboatoy and ae atifactoy. Page 148