DEVELOPMENT OF A PROGRAMMABLE LOAD

Transcription

1 DEVELOPMENT OF A POGAMMABLE LOAD Ulch John Mnnaa A dsseaon submed o he Faculy of Engneeng, Unvesy of he Wwaesand, n fulflmen of he equemens fo he degee of Mase of cence n Engneeng. Johannesbug, 2006

2 DECLAATION I declae ha hs dsseaon s my own, unaded wok. I s beng submed fo he degee of Mase of cence n he Unvesy of he Wwaesand, Johannesbug. I has no been submed befoe fo any degee o examnaon n any ohe Unvesy. day of 2

3 ABTACT The Volage Dp Tes Facly a he Unvesy of he Wwaesand ulses a essve load dung esng of vaable speed dves. Ths mehod poduces valuable esuls egadng he pefomance of dves unde dp condons. I has been shown ha load ype does nfluence he pefomance of dves and hs vaaon canno be esed unde cuen condons as only lnea loadng s aanable wh essve loads. Ths hess poposes a pogammable load based on he concep of feld-oened conol of an nducon moo. The conceps nvolved wh feld-oened conol ae dscussed and shown o be suable fo hs applcaon. An mplemenaon saegy ulsng cusom-desgned sofwae and an off-he-shelf VD s developed and execued. The pefomance of he pogammable load s analysed unde boh seady-sae and dynamc condons. 3

4 ACKNOWLEDGEMENT Thanks o AFTONIC fo supplyng he vaable speed dve fo he developmen wok and D JM van Colle Ws fo faclang hs. Thanks o D Van Colle fo hs gudance on he opc. Thanks also o obe Koch fo hs commens. Fuhe hanks o Hay Fellow and Indes Pllay Ws wokshop fo help wh he mechancal and eleccal se-up. 4

5 CONTENT Page DECLAATION 2 ABTACT 3 ACKNOWLEDGEMENT 4 CONTENT 5 LIT OF FIGUE 8 LIT OF TABLE 9 NOMENCLATUE 10 1 INTODUCTION Poblem aemen 11 2 BACKGOUND Volage Dps Effecs of Volage Dps on Vaable peed Dves 16 3 EFFECT OF LOADING CHAACTEITIC ON VD 21 PEFOMANCE 3.1 Consan Toque Consan Powe Quadac Toque Dynamc Condons Impac of load ypes unde dp condons 26 4 THE VOLTAGE DIP TET FACILITY The layou of he Tes Facly 29 5 THE POGAMMABLE LOAD Load equemens pace Veco Theoy of AC Moos Genealsed pace Veco Equaons 34 6 FIELD OIENTED CONTOL OF INDUCTION MOTO Conol aegy fo Feld Oened Conol 47 5

6 7 IMPLEMENTATION TATEGY Conol of Load Moo Conol ofwae Key Issues Affecng Pefomance 52 8 EQUIPMENT AND OFTWAE Equpmen Vaable peed Dve Inducon Moo Analogue Ineface ofwae Pogammng Language ofwae Oulne Conol Algohm Pocess Flow 59 9 HADWAE CONTUCTION Powe upply Daa Acquson Cad Vaable peed Dve Moo and Dve Connecons Basc ysem YTEM CONTOL IMPLEMENTATION Vaable peed Dve engs Dve Mode Analogue Inpus Analogue Inpu Polay oaon and peed Decon un-op Conol Pogammable Load Opeang Connecons Inpu and Ccu Fleng ofwae Implemenaon Inpu and Daa oage 70 6

7 Daa Inpu and Uns Conol Algohm Implemenaon gnal Nose and ensvy Implemenaon and Developmen Issues UE-INTEFACE YTEM TETING EULT eady-sae Tes Mehodology Quadac Toque Consan Toque Consan Powe Lnea Toque esuls Dynamc Tesng Mehodology Quadac Toque Consan Powe Consan Toque Lnea Toque Acceleaon Lms Maxmum Acceleaon Mnmum Acceleaon CONCLUION AND ECOMMENDATION Conclusons ecommendaons 99 EFEENCE 100 Appendx A Implemenaon Ccu Dagam 103 7

8 LIT OF FIGUE Fgue Page 1. Dffeence beween sag and dp magnude Measued volage dp paamees The hee basc volage dp ypes Typcal AC Dve Topology Lne cuens fo balanced volage supply Lne cuens fo 3% volage unbalance Toque-speed Chaacesc fo Consan Toque Load Toque-speed Chaacesc fo Consan Powe Load Toque-speed Chaacesc fo Vaable-Toque Load peed vs. Dp duaon fo 3 load ypes Toque vs. Dp duaon Block dagam of volage dp es-bed Poposed layou epesenaon of 2-pole 3-phase AC nducon moo ao mmf seen by oo ao cuen space veco dagam Block dagam of feld oened conol of an nducon moo oo shafs coupled Block dagam of Pogammable Load Conol flow sucue Basc Wng fo Vecoflux dve Dve and wng connecons Mnmum conol wng Wng fo manual un-deconal analogue conol Analogue npu sengs Inenal closed loop conol of VD Conol connecons o VD emnal sp essve dvde, dffeenal amplfe and Buewoh fle ecangula appoxmaon Gaphcal use-neface fo pogammable load Quadac Toque eady-ae esponse Consan Toque eady-ae esponse 80 8

9 33. Consan Powe eady-ae esponse Lnea Toque eady-ae esponse Quadac Toque esponse Consan Powe esponse Consan Toque esponse Lnea Toque esponse Maxmum Acceleaon and peed Acceleaon Cuve peed Cuve 95 LIT OF TABLE Table Page 1. Phase volage magnude dung LGF on phase A Example of load ype applcaons Conol connecons Componen values Use-neface pogammable paamees Quadac Toque eady-ae esponse Consan Toque eady-ae esponse Consan Powe eady-ae esponse Lnea Toque eady-ae esponse Aveage acceleaon 1000ms - Quadac Compason of expeced vs. acual oque 1000ms - Quadac Aveage acceleaon 100ms Quadac Compason of expeced vs. acual oque 100ms - Quadac Aveage acceleaon 1000ms Consan Powe Compason of expeced oque vs. acual oque 1000ms Consan Powe Aveage acceleaon 100ms Consan Powe Compason of expeced oque vs. acual oque 100ms Consan Powe Aveage acceleaon 1000ms Consan Toque Compason of expeced oque vs. acual oque 1000ms Consan Toque 90 9

10 20. Aveage acceleaon 100ms Consan Toque Compason of expeced oque vs. acual oque 1000ms Consan Toque Aveage acceleaon 1000ms Lnea Toque Compason of expeced oque vs. acual oque 1000ms Lnea Toque Aveage acceleaon 100ms Lnea Toque Compason of expeced oque vs. acual oque 100ms Lnea Toque peed Changes ove a 3 second neval a low levels of acceleaon 97 NOMENCLATUE AC A/D AD D/A DC LV EPI EMC HV IEEE IGBT LED LV MV PC PLC PQ PWM.M. LGF VD Alenang Cuen Analogue To Dgal Adjusable peed Dve Dgal To Analogue Dec Cuen Low Volage Elecc Powe eseach Insue Elecomagnec Compably Hgh Volage Insue Of Eleccal And Eleconc Engnees Insulaed Gae Bpola Tansso Lgh Emng Dode Low Volage Medum Volage Pesonal Compue Pogammable Logc Conolle Powe Qualy Pulse Wdh Modulaon oo Mean quaed ngle-lne-to-gound faul Vaable peed Dve 10

11 1. INTODUCTION 1.1 POBLEM TATEMENT Volage dps ae esmaed o cos ouh Afcan ndusy appoxmaely 1.2 bllon ands [1]. Ths cos s due o poducon losses caused by he ppng of plan equpmen. A soluon o hs poblem can only be sough once he behavou of equpmen unde volage dp condons s undesood. The Powe Qualy Tes Laboaoy PQ Tes Lab s he esul of collaboaon beween he Unvesy of he Wwaesand and Eskom- TI. The PQ Tes Lab was ognally developed o nvesgae he esponse of vaable speed dves unde volage dp condons. The capably of he laboaoy has been exended o nclude he esng of auxlay plan equpmen e.g. conacos, elays, pc powe supples. The PQ Teslab ulses a developed mehodology o oban nfomaon egadng he mpac of volage dps on he above-menoned equpmen and povdes a valuable npu o ndusy egadng equpmen sensvy. The am of he laboaoy s o faclae powe qualy nvesgaons and sysem compably sudes. The am of sysem compably sudes s o ende ndusy nsensve o he effecs of supply dsubances by ehe goous equpmen specfcaon o he mplemenaon of emedal soluons on exsng equpmen [2]. A pesen esng s done unde essve load condons. Ths mehodology poduces valuable genec nfomaon egadng he esponse of equpmen o volage dps, howeve has been shown ha vaable speed dves have vayng esponses o volage dps deemned by load ype [3]. Ths epo nvesgaes he vaous load ype scenaos pesen n ndusy and poposes he use of a pogammable load o smulae 11

12 ndusal condons n he laboaoy. A load opology s poposed wh suppong heoy. The noducon of a pogammable load o he PQ Teslab wll enhance he ably of he laboaoy o measue he esponse of vaable speed dves unde a ange of condons elaed o volage dp and load ype vaaons. 12

13 2. BACKGOUND 2.1 Volage Dps Volage dps ae also efeed o as volage sags, mos noably n he UA. Fgue 1 ndcaes he dffeence n defnon beween dp magnude and sag magnude. Volage dp and dp magnude wll be efeed o n hs documen, unless ohewse saed. Nomnal upply Volage Dp Magnude ag Magnude 0 Fgue 1: Dffeence beween sag and dp magnude [4] A volage dp s defned by N-048, he ouh Afcan egulaoy sandad govenng qualy of supply as: A sudden educon n he.m.s. volage, fo a peod beween 20ms and 3 s, of any o all of he phase volages of a sngle-phase o a polyphase supply. The duaon of a volage dp s he me measued fom he momen he.m.s volage dops below 0.9 pe un of declaed volage o when he volage ses above 0.9 pe un of declaed volage. Hee he declaed volage s defned as The volage declaed by he uly as he volage a he pon of supply. Ths s llusaed n Fgue 2. 13

14 Declaed volage.m.. volage Dp heshold Dp magnude % of declaed Duaon ms Fgue 2: Measued volage dp paamees [6] The chaacesaon of volage dps n ems of magnude and duaon povdes he essenal nfomaon fo he quanfcaon of volage dps [4]. Ths nfomaon howeve does no adequaely explan all effecs of volage dps on equpmen [2]. Volage dps can also be epesened by means of.m.s values and phaso dagams. Usng phaso dagams, hee ypes of volage dps ae descbed: hee-phase dps, snglephase dps and phase-o-phase volage dps. These ae llusaed n fgue 3. V B V N VWN V W V B V N V WN V W V B V N V W B V BN V WB W B V BN V WB W B V BN V WN V WB W a Thee-phase dp b ngle-phase dp c Phase-o-phase dp Fgue 3: The hee basc volage dp ypes [2] 14

15 Volage dps ae fuhe descbed n IEEE [7] accodng o he followng ls of descpos. M magnude Duaon Pon-n-wave of naon Pon-n-wave of ecovey Phase shf ae of change of phase shf Mssng volage The elaonshp beween he hee phases s also mpoan o many ypes of ndusal equpmen as hey may opeae off he dffeence beween wo phases. The phase shf beween wo phases s hen ccal. Ths s case when consdeng dves and he pefomance unde volage dsubances. The hee phase suaon s descbed by:.m. magnude unbalance ao Dffeence volage Phase angle elaonshp Ths nfomaon povdes specfc nsgh no volage dsubance wavefoms and allows engnees o deemne he eason fo equpmen mal-opeaon a specfc sghs. Ths daa can also be used o bee desgn equpmen o deal wh nomal powe sysem dsubances [4]. 15

16 2.2 Effecs of Volage Dps on Vaable peed Dves A ypcal AC pulse wdh modulaed PWM dve consss of hee sages namely: A ecfe sage conveng ncomng AC volage o DC volage, a DC bus song enegy and mnmsng volage pple as well he nvee sage ha conves DC o an AC volage of he equed magnude and fequency usng PWM. Fgue 4: Typcal AC Dve Topology [8] AC dves nomally ulse an unconolled ecfe sage and he capaco n he DC lnk povdes some measue of enegy soage whch assss n volage dp de-hough of AC dves, mos AC dves ae howeve vey sensve o volage dps. The DC bus volage deceases dung a volage dp. When hs volage eaches he unde-volage p pon, he dve wll p on undevolage [9]. The unconolled ecfe sage of he dve does no eque mng nfomaon fom he ecfe and gnoes zeo cossngs. Ths means 16

17 ha he phase shfs dung volage dps does no sgnfcanly affec he pefomance of AC PWM dves [10]. The majoy of volage dps ae due o sngle-lne-o-gound-fauls LGF [10]. Dung a LGF he volage on he fauled phase goes o zeo vols a he locaon of he faul. The volage a a cusome busba s nfluenced by faul ype, faul mpedance, dsance o cusome busba and ansfome connecons ec. [4, 10]. Table 1 [4] shows phase volage magnudes on a ansfome seconday dung a LGF. The faul occued on phase A. Tansfome Lne volages on he ansfome seconday connecon Vab Vbc Vca Y/Y D/D Y/D D/Y Table 1: Phase volage magnude dung LGF on phase A [4] Volage unbalance ceaed dung such dps may cause ppng of he dve. The npu ecfe daws cuen when he phase volage exceeds he DC bus capaco volage. Fo a balanced npu volage supply he lne cuen wavefoms ae ypcally as n Fgue 5, whch s fo a 5hp 3,75KW AC dve. 17

18 Fgue 5: Lnes cuens fo balanced volage supply [10] 18

19 Fo unbalanced phase volages such as hose occung dung LGF`s he npu cuen may be n excess of 200% of he nomal ang and peak cuen dawn may be 4 mes he nomal [10]. These lage cuens exs due o he capaco no dawng cuen fom he dpped phase ha s unde he DC bus volage; hence he capaco dschages moe soed enegy o he moo and load. When he phase ha has no dpped fowad bases he ecfe, he capaco s echaged fom hs lne causng lage cuens o flow n he lne. AC dves commonly p due o undevolage on a se heshold o ovecuen caused by hgh lne cuens [10]. Fgue 6 ndcaes he lne cuens dawn on a 3% volage unbalance fo he same AC dve llusaed n Fgue 5. 19

20 Fgue 6: Lne cuens fo 3% volage unbalance [10] 20

21 3. THE EFFECT OF LOAD CHAACTEITIC ON VD PEFOMANCE To undesand he effecs of load on VD pefomance a good sang pon s he applcaon of he load n an ndusal suaon.e. he dvng of a load by an elecc moo. An eleccal moo conves eleccal enegy no oaonal mechancal enegy. The oo shaf spns a a specfc speed wh he equemen o un o move a devce. Ths devce s he load and a cean amoun of foce s equed o nae movemen of he load and o manan hs movemen. Ths wll deemne he chaacesc of he load. Thee ae hee ems of mpoance when chaacesng elecc moo loadng: oque, speed and nea [11]. Toque s defned as he mechancal foce mulpled by vecal dsance leve am [12]. I s a measue of how much foce s equed o cause an objec o oae.e. he load. The mec un fo oque s Nm. peed s he oaonal velocy of he dvng shaf. I s measued n.p.m evoluons pe mnue. Also measued as ωomega wh un adans pe second. Inea s he endency of an objec o ess any change n moon. Mass s used o measue nea. Two condon saes have o be consdeed fo analyss of Load ype. These ae seady sae condons and dynamc condons. eady sae condons mean ha he load s no undegong acceleaon o deceleaon. Toque and speed ae ploed agans each ohe o gve a epesenaon of he seady-sae oque equemens of he load houghou s speed ange. 21

22 The seady-sae oque-speed cuve can nomally be fed o a mahemacal equaon elang oque o speed [11]. n= n ΤL = Anω m Indusal loads geneally f no hee load ype caegoes: consan oque, consan powe and vaable oque loads [11] 3.1 Consan Toque Consan oque loads have oque equemens ha ae ndependen of speed. The oque equemen emans he same houghou he speed ange of he sysem. Fgue 7: Toque-speed Chaacesc fo Consan-Toque Load [11] Fgue 7 llusaes he chaacesc cuve fo consan oque loads and s mpoan o noe ha full oque s equed a zeo speed. Examples of consan oque loads nclude conveyos, exudes and posve dsplacemen pumps [11, 13]. The seady-sae equaon govenng hs load-ype s: Τ L = Α

23 3.2 Consan Powe The equaon defnng oaonal powe [12] s: Ρ = Τ ω m... 2 Whee: P = powe T = oque ω m = angula speed Equaon 1 ndcaes ha fo any consan value of powe, oque deceases as speed nceases and vce vesa. Fgue 8 shows he chaacesc cuve fo hs load-ype. Fgue 8: Toque-peed Chaacesc fo Consan-Powe Load [11] Equaon 1 s of he fom of a hypebolc funcon and he oque-speed cuve s heefoe nheenly of hs fom. Fgue 8 ndcaes ha he hghes equed oque s eached a low speeds. Examples nclude acon moos, canes, lahes and cene wndes [11]. 3.3 Vaable Toque Vaable oque loads n geneal follow a quadac oque-speed [11] cuve of he fom: Τ L 2 ω = Α ω + Α ω + 2 m 1 m Α

24 Whee: T L = load oque ω m = angula speed A 0 = consan Evey load has a pacula se of co-effcens ha descbe how load oque vaes wh speed. Examples nclude fans, blowes, cenfugal pumps, and compessos [11]. The oque-speed chaacesc s ypcally as n fgue 9. Fgue 9: Toque-peed Chaacesc fo Vaable-Toque Load [11] Fgue 9 llusaes he elaonshp beween oque and speed. Ths fgue pons ou he vaaon of oque wh espec o speed. Alhough he exac cuve fo vaable oque loads ae hghly dependen on specfc applcaons, he followng genealsaon can be used as a gudelne fo descbng vaable oque loads. 2 Τ ω... The cuve fo vaable oque loads can heefoe be appoxmaed by: Τ L 3 2 = A ω m The hee load ypes menoned above cove a ange of engneeng applcaons. Table 2 povdes a ls of applcaons specfc o each load ype. 24

25 LOAD TYPE CHAACTEITIC CUVE APPLICATION CONTANT TOQUE -conveyos, exudes, mlls, planes, scew pumps, pson pumps, lfs, wndes, posve dsplacemen pumps CONTANT POWE -acon moos, canes, lahes, cene wndes VAIABLE TOQUE Quadac funcon - blowes, cenfugal fans, cenfugal pumps, vacuum pumps, compessos Table 2: Examples of load ype applcaons [11, 13] 3.4 Dynamc Condons eady sae condons and load nea ae used o descbe he dynamc load oque esulng fom acceleaon o deceleaon [11]. 25

26 Newon s econd Law saes: The elaonshp beween an objec's mass m, s acceleaon a, and he appled foce F s F = ma [12]. Fo oaonal sysems hs means ha loads wh hgh nea wll ceae a oque n opposon o he sysem speed. I follows hen ha he magnude of he load nea wll affec he dve pefomance. Lage nea values wll mean moe soed mechancal enegy ha wll keep a sysem oang dung a volage dp. A load s descbed as havng a hgh nea f he load nea s moe han 5 mes he moo nea [13]. The equaon govenng dynamc oque condons s: Τ L = J L dωm + d n= Α...5 nωm Ths equaon compses an nea componen and a seady-sae componen, whch s sysem dependen as descbed pevously. 3.5 Impac of load ypes unde dp condons EPI have developed a 5-HP pogammable load and ess conduced usng hs load ndcae ha speed and oque changes ha ake place dung volage dps dffe fo vaous load ypes. [11] Tess wee conduced on quadac, consan powe and consan oque load ypes. Thee phase volages dps up o 30% of nomnal wee appled o he npu of he dve unde es. The ess wee caed ou wh a flyng esa enabled. The nal condons fo he es was speed = 1740PM and load oque = 20.5 Nm. [11]. The dps wee appled a 5, 10, 15, 20, 25 and 30 cycles. Fgue 10 and 11 use volage sags as opposed o volage dps. 26

27 Fgue 10: peed vs. Dp duaon fo 3 load ypes [11] Fgue 11: Toque vs. Dp duaon [11] 27

28 The esuls ndcae ha boh load ype and dp duaon has a sgnfcan effec on he on speed and oque changes. Fgues 10 and 11 show ha dffeen load ypes poduce dffeen oque and speed changes fo dencal volage dps. The unque esponse of each load ype o volage dps ndcaes ha load ype needs o be aken no consdeaon when volage dp esng akes place as could sgnfcanly affec dve pefomance and de-hough ably. 28

29 4. THE VOLTAGE DIP TET FACILITY The Powe Qualy Tes Facly PQ Tes Lab s locaed a he Unvesy of he Wwaesand and was ognally desgned o povde a dp mmuny esng facly fo vaable speed dves. The facly has been expanded o nclude volage dp esng of auxlay equpmen such as conacos, elays, pogammable logc conolles and pc powe supples. The volage dp esbed consss of he followng [15]: A supply conol PC Inpu A/D and oupu D/A neface cads A pogammable supply ncopoang an IGBT oupu nvee sage, suppled va hee-phase ecfe An oupu ansfome An nducon moo coupled o a DC geneao A vaac/ecfe o adjus he geneao feld A esso bank sevng as he geneao load 4.1 The Layou of he Tes Facly Wavefom conol PC Volage Dsubance sofwae Pogammable upply upply Volage upply Cuen DC Volage Moo peed Adjusable essve Load Oupu Tansfome Vaable peed Dve DC geneao Fgue 12: Block dagam of he volage dp es-bed [2] 29

30 A PC s used o synhesse a volage dp by specfyng volage dp paamees such as he volage po o he volage dp, he volage dung he volage dp, he phase angle and he volage ecovey pofle. Paamees can be adjused ndependenly fo each of he phases such ha sngle-phase, wo-phase and hee-phase volage dps can be esed. The es facly, shown n Fgue 12, consss of he followng elemens [2]: The PC, unnng he dp esng sofwae, s used o conol he esng. The volage dp sofwae conols he pe-dp wavefom geneaon and volage dp geneaon by he pogammable supply. Dung and mmedaely afe an appled volage dp, VD measuemens ae ecoded fo analyss afe he es. The pogammable supply eplaces he mans supply o he equpmen. The pogammable supply s IGBT based and, wh he conolle ha was developed, s capable of geneang any complex volage dp wavefom. The VI o CI nvee s conneced o a sandad nducon moo, whch n un s coupled o a DC geneao load. The DC geneao, whch s coupled o he nducon moo, s conneced o a essve load bank. By adjusng he geneao feld cuen he load pesened by he DC geneao s vaed. Wh consan feld and essve load he DC geneao load pesens a lnea oque vesus speed chaacesc. The volage dp es facly n s pesen fom povdes a valuable ool n pefomng dp mmuny esng of vaable speed dves. I has, howeve been shown n he pevous chape ha load chaacesc plays a ole n he pefomance of dves unde volage dp condons. The pesen 30

31 load ulsed n he laboaoy does no compensae fo vaaon n load ype and pesens a lnea oque-speed cuve. Ths epo poposes eplacng he cuen essve load wh a pogammable load ha s capable of geneang he equed oque speed chaacescs and smulang dynamc oque condons. Fgue 13 llusaes he poposed sysem layou. Wavefom conol PC Volage Dsubance sofwae Pogammable upply upply Volage upply Cuen DC Volage Moo peed Adjusable essve Load Pogammable Oupu Tansfome Vaable peed Dve load DC geneao Fgue 13: Poposed layou 31

32 5. POGAMMABLE LOAD 5.1 Load equemens The funcon of he pogammable load wll be o smulae ypcal ndusal loads as descbed pevously. Ths wll nclude: Maxmum oque a zeo speed mulae nea effecs unde deceleaon and acceleaon Quck esponse o changes n ω angula velocy va feedback The mplemenaon of he load nvolves he applcaon of an opposng oque smulang boh seady sae and dynamc condons. Ths lms he conol schemes ha ae applcable fo hs nsance. Ths epo poposes ulsng and nducon moo o povde he opposng oque smulang he load. Classcal AC dves ae lmed n he ably o fulfl hs funcon fo he followng easons [16]: The machne models and chaacescs ae only vald fo seady sae No 3-phase mbalance managemen as hee s no consdeaon of phase neacons. Dffculy conollng vaables wh a snusodal efeence. Conol sucue Mus be dedcaed o a specfc moo ype.e. synchonous o asynchonous Feld oened conol offes accuae conol fo boh seady sae and dynamc condons as ncopoaes exac moo ansen equaons. Feld oened conol consss of conollng he sao cuens epesened by a veco. I s based on pojecons ha ansfom a hee-phase me and speed dependen sysem no a wo sae me nvaan sysem. As feld conol s based n pojecons, he conol sucues handle nsananeous eleccal quanes. Ths means ha 32

33 he conol s accuae n evey wokng nsance, boh seady sae and nsananeous. An undesandng of space veco heoy of AC moos s equed befoe movng no feld-oened conol heoy. 5.2 pace Veco Theoy of AC Moos In space veco heoy he acual wndng cuens ae eplaced wh equvalen oang cuen space vecos. These n un poduce oang flux space vecos ha nduce volages n he wndngs. The wndng volages ae also eplaced wh volage space vecos. ao volage equaon n space veco fom s: Whee v v = d ψ d s he oang sao volage space veco s he ong sao cuen space veco s he sao wndng essance ψ s he oang sao flux lnkage space veco mlaly he oo volage equaon s: Whee v v = d ψ d s he oang oo volage equaon s he oang oo cuen space veco s he oo wndng essance ψ s he oang oo flux lnkage space veco 33

34 5.2.1 Genealsed Volage pace Veco Equaons Assume a 2-pole moo wh 3-hase wndngs on sao and oo. 1 ao cuen mmf axs oo cuen mmf axs α 2 oo wndng efeence axs 3 ao wndng efeence axs β ε 1 Fgue 14: epesenaon 2 pole 3-phase AC nducon moo Defne: he sao wndng efeence axs as he axs of sao phase 1 wndng he oo wndng efeence axs as he axs of oo phase 1 wndng 1 as he nsananeous cuen n phase 1 wndng 2 as he nsananeous cuen n phase 2 wndng 3 as he nsananeous cuen n phase 3 wndng Fom hs he sao cuen space veco efeenced o he sao wndng efeence axs s defned as: s jα j0 j2π /3 = e = e + e + e j4π / Whee: s he magnude of he sao cuen space veco as a funcon of me 34

35 α s he angle of he sao cuen space veco as a funcon of me The acual wndng cuens ae consdeed o poduce saonay cuen space vecos whch when added ogehe poduce a oang cuen space veco The angula sepaaon of he saoney cuen space vecos ae a esul of he physcal sepaaon of he wndngs Balanced 3-phase cuens cause s o oae wh consan angula velocy and consan magnude, fo all ohe cases angula velocy and magnude ae no consan We defne he sao mmf space veco also efeenced o he sao wndng efeence axs as: F s = N s = N e = F e jα jα...10 whee: N s he numbe of uns pe phase on he sao wndngs F s s he magnude of he sao space wndngs α s he angle of he sao mmf space veco mlaly he oo cuen space veco efeenced o he oo wndng efeence axs s: jβ j0 j2π /3 = e = e + e + e j4π / Whch poduces a oo mmf space veco efeenced o he oo wndng efeence axs F = N = N e = F e jβ jβ...12 whee: N s he numbe of uns pe phase on he oo wndngs F s he magnude of he oo space wndngs β s he angle of he oo mmf space veco 35

36 Assumng on has zeo elucance, he oal mmf s dopped acoss he wo a gaps. I can be shown ha he above mmf space vecos oo and sao ogehe poduce he followng flux densy space vecos [17]. ao flux densy space veco B s s s [ F +ℵF ] = µ 2h oo flux densy space veco B [ ℵ F + F ] = µ 2 h whee: B s he magnude of he sao flux densy space veco B s he magnude of he oo flux densy space veco ℵ s couplng faco dependen on leakage 0 ℵ 1 µ 0 s he pemeably of a h s he a gap lengh The sao flux densy space veco gves se o flux lnkage n each of he 3 phase wndngs. When hese 3 flux lnkages ae vecoally added hey poduce he sao flux lnkage space veco: s 3lNπ s ψ = B whee s he adus of he sao wndng l s he axal lengh of he oo 36

37 Equaon 15 shows ha he sao flux lnkage veco space veco s elaed o he sao flux densy space veco by a consan of popoonaly. ubsung equaon 13 no equaon vs 3µ lnπ s 3µ 0lN Nπ ψ = + 8h 8h e 0 jε µ ln The em 0 π has he fom of self-nducance of he sao 8h 3µ ln N wndng and s denoed by L, whle 0 π has he fom of 8h muual nducance of sao and oo wndngs and s denoed by M. Then: s ψ = L s + M e jε...17 mlaly fo he oo L 2 3µ 0 ln π = s he self-nducance of he 8h oo wndng, and he oo flux lnkage space veco s: ψ = L + M s e jε...18 I s now possble o elae he cuen space vecos and he volage space vecos n ems of essances, self and muual nducances. ubsung no Equaon 7 we ge Equaon 19, he sao volage space veco: 37

38 [ ] j j j j s j s s s s s e d d jm e d d M e d d jl e d d L e d d M d d L d d v ε β ε β α α ε ε β α ψ = + + = + = mlaly fom equaon 8, we ge he oo volage space veco equaon 20: [ ] j j j j j s e d d jm e d d M e d d jl e d d L e d d M d d L d d v ε α ε α β β ε ε α β ψ = + + = + = v The Toque Equaon A foce f s poduced when a conduco of lengh l and cayng a cuen s placed n a magnec feld wh a flux densy B: F=Bl In an nducon moo a oque s poduced when he oo cuen flows hough he oo conducos ha le n he magnec feld poduced by he sao cuen mmf. oo cuen does no conbue o oo oque as s maxmum value les whee cuen densy s zeo [17]. 38

39 The sao mmf seen by he oo wndngs s found by mulplyng ha seen by he sao by e -jε. ee fgue 14. F = F s e jε When leakage s ncluded, hen he mm s educed by a faco of ℵ. Assumng ha on has zeo elucance, he mmf s dopped acoss he wo a gaps and he flux densy space veco poduced by he sao bu seen by he oo s: B = = µ 0ℵN 2h µ 0 ℵF 2h Ths flux densy space veco s algned wh he sao cuen space veco as seen by he sao wndngs. B oo wndng efeence axs α-ε ϕ ε ao efeence axs wndng α Fgue 15: ao mmf seen by oo [17] Assumng a snusodal flux dsbuon aound he oo ccumfeence, he magnude of a angle ϕ s. 39

40 µ 2 0 h cos [ ϕ [ α ε ] The effecve oo cuen a angle ϕ s needed o calculae he oque poduced. The oo cuen pofle aound he oo s appoxmaed by an effecve oo suface cuen densy, whch can be shown o be [16]: J N ϕ, = sn 2 [ ϕ β ] Then he oque conbued by an elemenal conduco a angle ϕ o he oo wndng efeence axs wh wdh dϕ s: dt e = - x flux densy x dϕ x suface cuen densy x axal lengh µ 0ℵN = 2h µ 0lℵN = 4h N cos [ ϕ [ α ε ] dϕ sn[ ϕ β ] cos N 2 [ ϕ [ α ε ] sn[ ϕ β ] dϕ l bu M 3µ 0 ln N π = 8h Theefoe: dt e 2 = M 3π cos [ ϕ [ α ε ] sn[ ϕ β ] dϕ...24 The oal elecomagnec oque s obaned by negang aound he oo ccumfeence: 40

41 T 2 3π 2π e = M cos[ ϕ [ α ε ] sn[ ϕ β ] 0 dϕ and cosasnb=1/2[sna+b+snb-a heefoe: T e 1 = M 3π 2 = M 3 sn 2π 0 [ sn2 [ ϕ α β + ε ] + sn[ α ε ] β ] [ α ε ] β ] dϕ The angle [α-ε]-β s he angle beween he sao cuen space veco and he oo cuen space veco. The sne em ndcae ha he componen of he sao cuen space veco ha s quadaue o he oo cuen space veco s he sgnfcan componen. Theefoe: 2 Te = Msq Whee I sq = sn[[α-ε]-β] s he componen of he sao cuen space veco poducng he flux quadaue o he oo cuen mmf space veco. The quadaue componen of he sao cuen space veco poduces he feld maxmum n he poson whee oo cuen densy s a a maxmum, hus poducng he oque [17]. The dec componen of he sao cuen space veco poduces he feld when oo cuen densy s zeo and heefoe makes no conbuon o he elecomagnec oque poduced. 41

42 AC moos boh synchonous and nducon can heefoe be descbed by he followng fou space veco equaons: [ ] j s s s e d d M L v ε + + = [ ] j s e d d M d d L v ε + + =...29 d d ω ε = [ ] [ ] sn 3 2 T T M d d J F L = β ε α ω Whee ω s he angula velocy of he oo T L s he opposng load oque T F s he opposng fcon oque 42

43 6. FIELD OIENTED CONTOL OF INDUCTION MOTO The oo flux densy space veco can be calculaed fom [17]: [ ] [ ] j s e N N h F F h B ε µ µ +ℵ = + ℵ = hen subsung = = π µ π µ ln h N h ln L and ℵ = = π µ π µ ln h N h N ln M heefoe [ ] j s e M L ln B ε π + = The sao and oo self-nducances can be expessed n ems of muual and leakage nducances: [ ] [ ] M M M L M M M L σ σ σ σ + = + = + = + = whee σ and σ ae defned as he sao and oo leakage coeffcens especvely. ubsung equaon 32 no equaon 31: [ ] [ ] j e ln M B ε σ π + + = I s mpoan o noe ha cuen space veco nsde he backes deemnes he oo flux densy space veco. Ths s defned as he magnesng cuen space veco. efeenced fom he sao wndng efeence axs: [ ] 1 e s j s m + + = ε σ 43

44 = m e jρ whee ρ s he angle of he magnesng cuen efeenced o he sao wndng efeence axs. Veco conol deals wh he conol of he magnude of he oo magnesng cuen and he conol of oque va he quadaue componen of he sao cuen space veco. Analyss wll be done by efeencng o he magnesng cuen efeence axs ha wll be denoed by he supescp m. axs The sao cuen space veco hen becomes: m = s e j ρ Ths veco s hen esolved no dec and quadaue componens: = j...36 m sd + whee sd s he dec componen algned wh he oo flux axs sq sd s he quadaue componen pependcula o he oo flux The sao cuen space veco dagam hen becomes [16, 17]: sq 44

45 oo wndng efeence axs ω δ ω m Magnesng cuen efeence axs sd ρ ε α ao wndng efeence axs Fgue 16: ao cuen space veco dagam Whee ω m s he angula velocy of he magnesng cuen flux axs elave o sao wndng efeence axs. 2 3 Fom equaon 25: T = M sn[ α ε ] β ] e I can be shown ha he oque equaon fo nducon moos s gven by he followng equaon: T e 2 M = 31+σ m sq I m by defnon conols oo flux magnude, s necessay o deemne how can be conolled va he sao cuen. The elaonshp beween I m and I sd and I sq s as follows: 45

46 [ ] [ ]...38 d d d d L sd m m sd m m = + = = + τ and [ ]...39 sq m m = ω ω τ Combned wh: T T M d d J F L sq m + = σ ω...29 d d ω ε = descbes he behavou of an nducon moo unde feld-oenaed conol. 46

47 6.1 Conol aegy fo Feld-Oened Conol The sao cuen componens sd and I sq ae ansfomed o he sao cuens 1, 2 and 3 va wo nemedae cuens whch ae he dec and quadaue componens efeenced o he sao wndng efeence axs as opposed o he magnesng cuen axs. The sao cuen space veco efeenced fom he sao wndng efeence axs s: s = 2π j 3 3 = + e + e sa 1 + j sb π j efeencng he sao cuen o he magnesng cuen efeence axs: Theefoe: m = = = e jρ jρ [ + ] e...42 sa sd + j sb sq s sd sq = = sa sb cos ρ + cos ρ sb sa sn ρ...43 sn ρ...44 Then knowng he followng: sa sb = = 1 2 2π 4π + 2 cos + 3 cos π 2π sn + 3 sn and assumng an solaed neual, heefoe: =

48 The followng elaonshps elang sb and sa o he sao cuens can be deved: 1 2 = = 2 3 sa sb 1 3 sa = 3 sa 1 3 sb...50 These equaons lead o he followng block dagam fo feld-oened conol: 48

49 efeence peed Conolle efeence Flux efeence Toque Isq Isb Conolle Isd e jρ Modulao Isa Phase ple peed Flux Magnude ρ Fgue 17: Block dagam of feld oened conol of an nducon moo I3 I2 I3 Thee phase supply Convee Moo 49

50 7. IMPLEMENTATION TATEGY The heoy pesened n he pevous chape llusaes ha an nducon moo unde feld-oened conol can be manpulaed o delve accuae oque conol. Ths makes an deal conol phlosophy fo he use n a pogammable load. Implemenaon of a pogammable load ulsng an nducon moo o geneae he smulaed load oque would nvolve dvng he moo n opposon he moo unde es MUT. MUT LOAD MOTO Fgue 18: oo shafs coupled Fgue 18 llusaes he mehod of applyng an opposng oque by couplng he oo shafs of he MUT and he load moo. 7.1 Conol of Load Moo The heoy of feld-oened veco conol llusaes ha s a vable soluon o povde he accuae conol equed o smulae ndusal load condons. Veco conol povdes good dynamc esponse a he expense of a complex convee. The developmen of such a convee would, n he opnon of he auho, be a me-consumng and complex ask. Ths would lead o hgh coss n ems of man hous equed fo he developmen. An alenave o developng a convee wh veco conol funconaly s o puchase a un wh he equed funconaly off he shelf. Ths s vable as many moden convees ulse veco conol due o s nheen advanages. 50

51 An AC moo s chosen above he alenave of a DC moo whch s hghly conollable as nducon moos ae wdely ulsed, nexpensve, eadly avalable and easly epaable. Fou quadan vaable speed dves ae used n eleccal bakng applcaons ncludng elevaos, wnches and canes [18]. Ths applcaon s a vaaon on hs ype of bakng applcaon. The poposed schemac of he pogammable load ulsng an off-heshelf VD o mplemen feld-oened conol s llusaed n fgue 19: MUT LOAD MOTO OFF-THE- HELF VD Volage and oo shaf speed measuemen cuen measuemen Conol Compue Conol sgnal Fgue 19: Block dagam of Pogammable Load Fgue 19 shows ha a conol compue wll be ulsed o conol he oupu oque va he VD. The am of he sysem s o smulae he oque chaacescs of ndusal loads as descbed n pevous chapes. The chaacesaon of loads as oque vs. speed funcons means ha he conol sysem s nheenly dependen on shaf speed o deemne he equed oque. Ths leads o a feedback sysem ha has he oaonal speed of he oo shaf as s pmay vaable. Ths sysem s of he fom epesened n fgue 17 bu ulses a vaable speed dve o elmnae he need o develop sofwae o compensae fo he equed phase-splng and angula oaons. 51

52 7.2 Conol ofwae The conol sofwae s equed o measue he angula velocy, calculae he appopae oque value fo ha specfc velocy and oupu a sgnal conollng he oupu oque of he vaable speed dve. Unde seady sae condons he oque oupu wll follow a specfed oque vs. speed cuve. Dynamc condons ae moe complex n ha nea has o be accouned fo. Measuemen of angula acceleaon becomes cucal as he poduc of nea and angula acceleaon deemnes he oque geneaed by he load unde hese condons see pevous chape. 7.3 Key Issues Affecng Pefomance Paamees ha deemne he pefomance of he pogammable load ae: Accuacy of oque Moden VD s ae accuae o whn a few pecen; measuemens wll need o be aken o deemne whehe he sysem s accuaely smulang he equed oque values fo se pons. esponse Tme To smulae loads he esponse of he load wll have o be vey fas o elmnae a sgnfcan me lag whch wll cause he accuacy of he sysem o be poo. Low peed Pefomance Boh consan oque and consan powe loads have he maxmum oque equemen a speeds appoachng zeo evoluons pe mnue. Ensung ha hs oque s accuae s mpoan as many dves lose accuacy a such low speeds. 52

53 8 EQUIPMENT AND OFTWAE 8.1 Equpmen The followng equpmen s equed o mplemen he pogammable load: Conol PC Vaable peed Dve Inducon Moo Tachomee Analogue-o-Dgal A/D Convee Dgal-o-Analogue D/A Convee VAIABLE PEED DIVE Veco oque conol dve 0-10V analogue oque conol npu 4-20mA oque measuemen oupu pefeably eveal VD s wee consdeed fo he mplemenaon. The AFTONIC VFX veco oque dve was chosen as a suable dve fo he followng easons. Veco conol funconaly Wdely used n ouh Afca Manufacue povdes good back-up o uses of he dve Lage amoun of maeal avalable on dve capables Flexbly- Ulses Inpu/Oupu I/O cads fo specfc neface and conols Choce of I/O cads avalable Zeo peed command Manual Toque Conol wh pope I/O cad nsalled The avalably of a ange of I/O cads o pesonalse he dve o a specfc funcon was an mpoan faco n he choce of VD. The 53

54 ulsaon of a vaable speed dve fo a pogammable load mplemenaon s a one-off nsallaon ha could poduce cean complcaons no necessaly found unde nomal opeang condons fo dves n ndusy. Ths poenal means ha a cean amoun of flexbly may be equed o adjus o hese unque ccumsances. The I/O cad allows he use o specfy whch vaables ae o be manually monoed and also povdes conol ove he cean aeas of opeaon of he VD e.g. veco conol. The cads chosen fo he load mplemenaon ae: AIO Analogue I/O cad-enables analogue npus of fequency, seng, oque lm values ec Inducon Moo Maxmum powe = 75kW. The powe ang of he moo was adjused fom he nal value of 150 kw o 75 kw due o he lmaons of he pogammable supply. The pogammable supply s lmed o 80kVA. ang he load any hghe han hs would mean s capable of opeang n a ange no whch he equpmen unde es EUT canno be opeaed due o he nheen lmaons of he supply Analogue Ineface The analogue neface cads wee specfed accodng o he followng cea: esoluon Numbe of neface channels equed ofwae dves avalable amplng fequency esoluon All convees ae equed o be mnmum 12-b convees. 54

55 Numbe of Channels equed The followng npus ae equed as a mnmum: Acual angula velocy Acual angula acceleaon Angula poson of shaf oponal ofwae Dves avalable To use he analogue neface cads effecvely whou undesandng he low-level desgn of he cad, sofwae dves ae equed. These sofwae dves ae accessed fom he pogam and pefom cad confguaon, analogue npu and oupu, mng and ohe funcons. The avalably of hgh-level dves makes possble o ulse cad effecvely n a much shoe me han f he cad wee o be accessed decly amplng Fequency The A/D cad wll be measung boh oque and angula velocy ansens. Expeence wh opeang he cuen pogammable supply has shown ha a samplng fequency of 4 khz s suffcen fo conol puposes. Moden A/D cads ae capable of samplng a fequences n excess of 100kHz Analogue neface cad I s pefeable o ulse a cad ha ncopoaes boh A/D and D/A funconaly on a sngle boad. Ths means ha a dve s only equed fo a sngle cad, smplfyng he pocess. Dung he pogam developmen a sngle cad can be addessed o boh npu and oupu sgnals and daa. The cad chosen was he Eagle Technology PCI-30 GA. Ths cad ncopoaes 16 A/D npu channels and 4 D/A oupu channels whch ae moe han adequae fo he equed applcaon. Eagle Technology also has dve sofwae avalable ha wll neface 55

56 wh mos wndows based pogammng languages. A wde ange of use nfomaon and asssance s avalable fom he webse and fom he company self as s a local company. 8.2 ofwae Pogammng Language A Wndows based pogam needs o be developed. Vsual Basc s ofen used o ceae applcaons due o he ease of ceang Wndows layous n. Vsual Basc ceaes code ha s nepeed as s un and hs esul n slowe applcaons. C++ execues code decly, whch means fase applcaons. C++ s also capable of boh hgh level and low-level nefacng. C++ wll be ulsed fo developmen of he conol pogam fo he pogammable load ofwae Oulne The sofwae o be poduced mus pefom he followng funcons: Use he shaf velocy o ohe sgnals o calculae he desed oupu oque value o he feld-oened dve Oupu oque feedback s equed o vefy he accuacy of he oque calculaon The oupu oque wll be calculaed accodng o he dynamc oque chaacesc equaon llusaed n chape 3. Ths model eques wo saes o be consdeed: seady sae and dynamc. The seady sae componen eques he followng paamees fo complee descpon: Load ype Inal oque Maxmum oque Load co-effcen fo vaable oque load Powe fo consan powe load 56

57 oaonal shaf velocy npu fom analogue-o-dgal neface The dynamc componen eques: Momen of nea specfc o pacula load oaonal acceleaon npu fom analogue-o-dgal neface These vaables cove he model paamees equed by he sofwae fo load smulaon puposes. The use neface o se up he load s also mpoan. The followng funconaly s equed: Non eal-me npu of paamees ave and ecall of specfc load cases The followng daa s equed o be soed and ploed on gaphs fo easy analyss: Acual angula velocy vs. me Acual angula acceleaon vs. me Toque vs. me 57

58 8.3 Conol Algohm Followng he mplemenaon saegy dscussed pevously, he flow cha fo he conol algohm s as follows: ELECT LOAD TYPE ENTE PAAMETE MAX TOQUE CUVE CO- EFFICIENT INITIAL TOQUE =T 0 MOMENT OF INETIA TAT LOAD TOQUE = T 0 MEAUE ω AND dω/d CALCULATE TOQUE = T X +J dω/d CONTOL IGNAL TO DIVE MEAUE ACTUALTOQUE YE TOQUE OUTPUT NO Fgue 20: Conol flow sucue 58

59 8.3.1 Pocess Flow The pogam sucue wll sa off wh seng of load ype.e. quadac, consan powe o consan oque. I wll hen flow no specfyng he load paamees fo any specfc ndvdual load and also he nal oque fo any se load. The sang of he load wll be synchonsed wh ha of he pogammable supply fo ease of use and conssen measuemens ploed agans me. Afe he sa-up oaonal velocy wll be measued and hs wll be he conol vaable fo accuae conol of he load oupu oque. The consan T x as descbed n he conol algohm s he desed oque accodng o a specfc oque-speed chaacesc. Feedback of oupu oque wll be equed o ensue accuacy of he sysem. 9. HADWAE CONTUCTION 9.1 Powe upply The powe supply o he pogammable load s a 3-phase supply va he 100kVA G.E.C ansfome n he Ws machnes laboaoy. 9.2 Daa Acquson Cad The daa acquson cad fo he mplemenaon of he pogammable load was changed dung he couse of wok fom he ognally specfed Eagle PCI30GA cad o he Eagle PCI730. The eason fo he change n he cad was due o he nably of he PCI30GA cad o adjus he numbe of daa uns ansfeed a a me fom he cad memoy buffe o he compue memoy buffe. Ths nflexbly led o a conol loop ha could only espond o a maxmum of less han 100 mes a second a a hgh samplng fequency of 100 khz. 9.3 Vaable peed Dve The vaable speed dve ulsed s he Emoon VFX Ths dve was ulsed due o he fac ha afoncs ouh Afca suppled he dve a cos pce ha esuled n a majo cos savng. The change n 59

60 vaable speed dve was acceped once had been vefed ha he VD had he necessay conol capables and exenal npus wh whch he conol of he dve could be mplemened. 9.4 Moo and Dve Connecons The Emoon VecoFlux VFX vaable speed dve has a emnal sp nsde he dve panel self ha allows nefacng wh exenal conol and/o measuemen equpmen. The VecoFlux dve was nally conneced accodng o he nsucons povded n he nsucon manual. Fgue 21 s an ndcaon of he basc wng layou fo he VFX dve. Fgue 21: Basc wng fo Vecoflux dve [18] Connecons L1, L2, L3 and PE as shown n he gaphc wee conneced o he equed 380V 3-phase supply n he laboaoy. The moo was conneced n dela whou he oponal oupu col and bake 60

61 esso. The cablng ulsed fo he dve and moo supply wee boh szed o handle he 146A maxmum cuen of he vaable speed dve. Fgue 22 shows he Vecoflux VFX dve on he lef and he wng o he dve on he gh. The mage shows he connecons o he powe supply and he cablng ou o he nducon moo. Fgue 22: Dve and wng connecons Once he basc consucon of he VD had aken place was possble o sa he pocess of opeang he VD and deemnng he equed nenal sengs of he VD fo ndependen opeaon, opeaon unde analogue conol and opeaon va analogue npus fom an ndependen conolle. 9.5 Basc ysem Opeaon of he Vecoflux dve s possble hough he conol panel on he fon of he dve. Connecons on he emnal sp on he nsde of he dve ae also equed dependng on he mode of opeaon equed. The conol boad conneco has he followng connecons ha ae elevan o he opeaon of he dve n hs pacula applcaon: 2 Analogue npus. 2 Analogue oupus. 2 Dgal npus. 61

62 2 Dgal oupus. ±10Vol DC supply. +24 Vol DC supply. un gh and un lef only opon. The mpoance of hese sengs n he opeaon of he dve n hs applcaon wll be dscussed lae n he epo. The mnmum wng o sa he dve and mplemen a basc fom of exenal conol s shown n fgues 23 and 24. Fgue 23 shows he mnmum conol wng equed fo sang up he dve. Fgue 23: Mnmum conol wng [18] The basc connecons fo manual un-deconal opeaon accodng o fgue 3 ae as follows: 10: HIGH Ths s mplemened by connecng emnal 10 o emnal VDC supply 62

63 Basc exenal analogue conol s acheved by ulsng he ±10Vol DC supply and connecng a poenomee acoss he supply connecons 1 and Vols 1 POTENTIOMETE Analogue In1 +ve Analogue In1 -ve -10 Vols 6 COMMON Fgue 24: Wng fo manual un-deconal analogue conol The man pupose of unnng he dve wh he 10kΩ poenomee was o enable he famlasaon and esng of he dve. In hs manne he lms and esponses of he dve could be esed. Ths se-up allowed oaon n one decon and allowed speed o oque conol n ha decon. Fuhemoe, hs allowed fo he seng up of he dve fo nefacng wh he conol compue. The VFX VD has a complex menu sysem and a hos of funcons ha can be se fo opeaon n a wde vaey of applcaons. These sengs need o be checked o ensue he dve opeaes as equed fo a specfc applcaon. Ths s especally ue fo opeaon unde expemenal condons. Usng he poenomee fo manual conol mean ha mos of he vaable speed dve sengs could be esed and adjused as equed po o he noducon of he dgal daa acquson and conol sysem. Ths mehod elmnaed an elemen of sk fom he developmen pocess. 63

64 10. YTEM CONTOL IMPLEMENTATION The conol mplemenaon has 2 majo componens ha affec: eng up of he VD o enable conol va an exenal souce hs efes o conol panel sengs as well as wng connecons. The exenal dgal conol sysem va daa acquson hadwae and conol sofwae Vaable speed dve sengs The followng dve paamees ae se up n a manne ha ensues easy neacon wh exenal conol souces: Dve Mode. Analogue npus. oaon and peed decon. Analogue oupus. un-op Conol. Pogammable Load Opeang Connecons Dve Mode The dve mode has hee possble sengs ha elae o he nenal conol loops of he VD. These ae: peed. Toque. V/Hz. The dve mode deemnes he paamee ha conol loops wll ack.e. speed o oque. The V/Hz paamee follows a loop ha conols fequency and allows mul-moo opeaons fom he VD. Ths specfc applcaon eques conol of he oupu oque and consequenly he dve mode seleced s oque Analogue Inpus The analogue npus ae only avalable fo he use when he VD s nenal PID conolle s de-acvaed. Once he PID conolle s 64

65 acvaed all value ae deved fom hs conolle and s se-pon values. The analogue npu vaable can han be se o ehe conol oque o speed. Fgue 25 shows he menu choces and he funcons as dsplayed n he conol panel of he VD. The efeence value efeed o n he dagam s he npu volage. Fgue 25: Analogue npu sengs [18] The dve mode and analogue npu need o be co-odnaed fo conol of a pacula paamee. In hs applcaon we dese oque conol, heefoe he dve mode seleced s oque and smlaly he vaable ha we npu s oque. Fgue 26 shows he block dagam fo he nenal conol pocess of he VD. I clealy ndcaes he need o de-acvae he PID pocess and he dffeenaon beween opeaon n speed mode and oque mode. In he oque mode of opeaon, he oupu oque of he dve acks he npu volage eceved a he analogue npu. Fgue 26: Inenal closed loop conol of VD [18] 65

66 Analogue Inpu Polay The seng of polay of he analogue npus s one of seveal sengs ha need o be popely se o allow oaon n boh decons.e. clockwse and an-clockwse. Wh a bpola seng of he npu vaable he dve wll ecognse a efeence sgnal fom 10V o +10V, wheeas wh a un-pola npu only he posve sgnals ae ecognsed. Ths has mplcaons fo changng he decon of oaon of he dve dung opeaon. The dve has been se up fo opeaon n un-pola mode. Compably poblems wee expeenced wh he D/A cad when opeang n bpola mode oaon and peed Decon The dve allows oaon n wo decons. eng oaon n boh decons enables bpola analogue npus. eng of he speed decon enables he sa sgnals o be ead n boh decons and he volage polay o deemne he decon of oaon. If hs s no se o ecognse boh decons any sa sgnal fom he conol panel wll be ecognsed as a sgnal o oae n one decon. The analogue npu wll be ead as an absolue value ha deemnes magnude, whch n hs case would be he amoun of oque equed. Ths seng has been evsed o allow opeaon n one decon only. Ths s accepable fo hs applcaon as he dve wll be acng as an opposng oque o effecvely a ype of bake un-op Conol The un-sop conol can be eceved fom a numbe of souces ehe nenal o he dve o fom exenal sgnals. The defaul seng s o eceve he command fom he sa and sop buons on he conol panel of he dve. Fo hs applcaon a sa sop sgnal fom he conol compue would allow full conol of he dve and hence he pogammable load fom he conol compue. Ths s acheved by 66

67 seng he souce of he un-sop conol o EMOTE, whch hen souces he un-sop commands fom he emnal sp on he dve. Pns 8 and 9 on he sp ae he un Lef and un gh commands especvely. A +24 Vol sgnal on ehe of hese wll un he moo n ha pacula decon Pogammable Load Opeang Connecons Manual conol of he dve fs had o be esablshed po o compuesng he conol. Ths was done by povdng he pope connecons o he dve as dscussed above and manually conollng he npu sgnal and he un-sop conol as descbed n able 3. PIN DECIPTION NOTE 2 Analogue Inpu +ve Toque conol sgnal 3 Analogue Inpu -ve gnal common 7 Neual/Common 8 un Lef Enables oaon o Lef 9 un gh Enables oaon o gh 10 Enable Enables dve opeaon Vol Hgh sgnal fo 8, 9, Neual/Common Neual efeence fo Analogue Oupu 1 Oupu peed Table 3: Conol connecons Fgue 27 llusaes he connecons made o mplemen analogue conol of he VD va a daa acquson cad. I should be noed ha he analogue oupus fom he VD wee eplaced by a moe elable mehod of usng a fleed achomee sgnal fo speed measuemen. 67

68 A/D Chan DAC 0 A/D OUTPUT CONTOL COMPUTE ON/OFF DAC 1 Fgue 27: Conol connecons o VD emnal sp Temnal 10 enables he opeaon of he dve and allows he oaon of he moo. Temnals 8 and 9 ae un Lef and un gh especvely. Wh boh of hese enabled he decon of oaon as well as he amoun of oque s deemned by he magnude and polay of he sgnal eceved a Analogue Inpu 1. Noe ha he Neual of he D/A cad and he VD ae joned o povde a common efeence fo he polay. The conol pogam deemnes he oupu oque fom he sgnal eceved fom analogue oupu 1 pogammed o oupu he oaonal speed of he moo of he VD. Ths oque s hen oupued as a 0-10 V sgnal o he VD. 68

69 10.2 Inpu Ccu and Fleng The sysem ulses moo speed as he conol vaable fo he pocess. A dgal achomee s used o measue moo speed. The achomee has an oupu equal o 90 Vols/1000.p.m. Ths s scaled o a ao of 10 Vols/1475.p.m by a essve dvde. The sgnal s hen npu hough a dffeenal amplfe and fleed o elmnae andom nose wh a second ode Buewoh fle wh a cu-off fequency ha s beween 100 and 110 Hz acual fequency Hz. The npu ccu and fle ae shown n fgue V +12V LM324 V1 3 - LM324 V V -12V + V 2 C C V LM V Fgue 28: essve dvde, dffeenal amplfe and Buewoh fle 69

70 The cu-off fequency of he Buewoh fle s: F c =1/2.83 x π x 3 x C The componen values ae lsed n able 4. COMPONENT C Opeaonal amplfe Table 4: Componen values VALUE 8.9kΩ 1kΩ 27kΩ 39Nf LM ofwae Implemenaon The daa acquson cad ha was chosen fo he fnal mplemenaon was he Eagle Technology PCI 730 cad. The basc pocess fo he mplemenaon of hs conol pocess consss of hee pas: Measuemen of conol vaable.e. ω. Calculaon of desed value. Oupu of value.e. Toque. I should be noed ha fo he developmen as well as mplemenaon puposes a 0-10V ange was assumed. Ths ange s easly exended o boh posve and negave volage anges. Ths s he case fo boh npu and oupu, as hs s he ndusy sandad ha s ulsed n he Emoon VFX vaable speed dve fo hs applcaon Inpu and Daa oage The Eagle cads ulse a common use develope neface ha povdes funcons o pefom specfc asks wh he cad as well as quey he saus of he cad and pocess n a vaey of ways. 70

71 The PCI 730 s capable of pefomng A/D conveson on 16 channels smulaneously. Fo hs applcaon, nally only one channel s equed. The followng paamees ae specfed a he sa of he pocess: amplng Fequency. Numbe of channels o sample. Channel. Fle n whch daa s soed - I should be noed ha he daa s soed n bnay foma. A sofwae buffe fo daa values. The daa samplng pocess s saed by callng he funcons o sa samplng and open he fle n whch daa s soed. The pocess s ended when he sop samplng and close fle funcons ae called Daa Inpu and Uns Toque s expessed n Newon-mees as a funcon of ω n adans pe second. The measued npu fom ehe a achomee o he analogue oupu of he VD self ulses he 0-10V sandad fo a speed ange of evoluons pe mnue.p.m beng he maxmum speed of he nducon moo. The volage npu has o be conveed o a fom ha wll poduce he coec scale of uns.e. adans pe second. Fo hs applcaon he govenng equaons ae hen: 10 Vols = 1475.p.m heefoe 1 vol =147.5.p.m ω ad/s = Vols x x 2p/60 1 Fuhe moe should be noed ha he PCI 730 cad measues he npu volage n uns of mcovols, heefoe: 71

72 ω ad/s = mcovols x x 2p/60/ Ths equaon epesens he elaonshp beween he measued npu volage and oaonal speed. I hen foms he bass fo any fuhe calculaons o deemne he oupu oque of he sysem and he oupu conol volage. 72

73 10.4 Conol Algohm Implemenaon The oupu oque equaon as saed pevously s: T = J dω/d + A n ω m The physcal vaable measued fo oaonal speed s a 0-10 Vol dscee sampled sgnal. In hs case each dscee sample epesens he oaonal velocy a ha nsan n me. The volage sgnal s ndcaed as velocy due o he fac ha he polay of he volage ndcaes he decon of oaon. The mehod used o deemne he devave of he dscee npu sgnal s ecangula Appoxmaon [1]. In ecangula appoxmaon he volage dffeenal dv/d f peod T s small enough s appoxmaed by: [vn vn-1]/t whee vn s he nh sample Fgue 29: ecangula appoxmaon [19] 73

74 The calculaon of he volage dffeenal s essenal n he deemnaon of he dynamc componen of he load model fo all load ypes. The volage devave deemnes he ae of change n oaonal velocy a any specfc nsan n me. Ths componen of he model mus be accuae and calculaed n eal-me gnal Nose and sensvy The poblem of sgnal nose on he analogue sgnal beng eceved by he A/D cad s handled by aveagng of samples. The ulsaon of sngle samples leads o shap changes n he npu speed beng ead due o he pesence of nose beng geneaed by boh he VD self and ohe exenal souces. A angula smoohng aveage fle s mplemened o mnmse he nfluence of andom sgnal nose on he calculaed acceleaon. The acceleaon a any pon n me s deemned by he subacon of wo aveaged speed measuemens close ogehe wh espec o me so ha he dffeenal mees he equemens fo accuae ecangula appoxmaon.e. small peod T Implemenaon and Developmen Issues The pocess of developng a pogam o mplemen a oque conolle compsed he followng seps: Famlasaon wh Daa Acquson Cad and assocaed sofwae The Eagle daa acquson cads ae povded wh a sofwae developmen k ha nefaces hough mos of he commonly used pogammng languages avalable. The famlasaon pocess conssed of undesandng he funcons of he vaous sysem calls. Ths pocess also ncluded ensung he leanng of he vaous samplng opeaons, whee he daa s soed and he foma n whch he daa s soed. 74

75 amplng The opeang sysem and lmaons of he daa acquson cad affec he appoach aken n ulsng he samples fom he daa cad n calculang he volage dffeenal. The PCI730 cad s opeaed by nsucng o sa he samplng pocess. The daa s hen wen o a hadwae buffe n he cad. A funcon call s equed o we he daa o he sofwae buffe whee can be vewed and accessed. Due o he fac ha any funcon call akes me o pocess, he samplng fequency s affeced f he daa s eeved afe each sample. Fo he conol of he pocess he daa s eeved afe a numbe of samples e.g. 10, 50, 100, 200 ec. Ths value s pe-se n he sysem se-up poon of he conol code. Ths ses up a new fequency fo he conol of he pocess as he conol fequency s hen: Conol Fequency = amplng Fequency/ Pe-se ample eeve Ths mehod n un necessaes ha he cad samplng fequency s scaled up o ensue ha he conol fequency s hgh enough o mplemen effecve sysem conol. The use neface allows he selecon of he samplng fequency n he ange 1-10 khz. The defaul samplng fequency s 4 khz Moo and VD Lms Pevenon of damage o he equpmen s mpoan fo he long-em opeaon of he pogammable load. The safe opeaon of he dve and moo s ensued by he 0-10V analogue npu sysem of he dve ha s mached by he 0-10V oupu of he A/D cad beng used. When he speed of he dve s beng conolled by he analogue npu, seng he moos maxmum opeang speed as he lm on he VD ensues safey. In hs case he moo opeaes a 1475.P.M. Ths hen ensues ha ±10Vol npu fom he A/D cad equaes o ±1475.P.M. The acceleaon and deceleaon n hs mode s lmed by he 75

76 oque lm of he dve. Wh he bake esso added o he sysem, deceleaon s lmed by he amoun of enegy ha s dsspaed by he bake esso. Wh opeaon n oque mode he moo oque s lmed by he maxmum oque seng of he VD, whch s eneed as a pecenage of he moo oque up o a maxmum of 400%. Fo hs applcaon, oupu oque s lmed o less han 100% of moo oque n boh decons. Lmng sysem speed n hs mode of opeaon s moe complex as a fxed oque appled o an opposng oque ha s of smalle magnude wll esul n connuous acceleaon. Consan speed o seady-sae opeaon s only possble when he opposng foces oques ae mached n magnude. The safey lm s ensued by a safey funcon bul no he code ha cus powe o he dve and moo f he speed lm s exceeded. 76

77 11. UE-INTEFACE The conol pogam was nally developed as a console foma pogam o esablsh he basc conol loop and funconaly of he pogam. A use-neface desgn was done on pape o ensue ha he npu and oupu paamees mached he funconaly of he conol pogam. The Wndows neface was developed usng Vsual C++. The man body of he pogam was hen nseed aound he Wndows code and modfed as equed o poduce a fnal wokng pogam ha nefaced wh he vaable speed dve and ensued ease of use. The gaphcal oupu of daa was added o poduce gaphs ha could be saved and e-used by he opeao of he pogammable load. Access o he daa pons s also possble n a foma ha can be coped no Mcosof Excel fo analyss and manpulaon. The use neface o confgue he load s shown n fgue 9. Fgue 30: Gaphcal use-neface fo pogammable load 77