Modeling and Control of Wind Energy Conversion Systems under High Wind Turbulence using Conventional, Fuzzy Logic and H-Infinity Controllers

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1 Internatonal Journal of Scence an Research (IJSR ISSN (Onlne: Inex Coperncus Value (201: 6.14 Impact Factor (201: 4.48 Moelng an Control of Wn Energy Conerson Systems uner Hgh Wn Turbulence usng Conentonal, Fuzzy Logc an H-Infnty Controllers M. Dya Nancy 1, K. Pama 2 1 Department of Electrcal Engneerng, Anhra Unersty College of Engneerng (A, Vsakhapatnam, Anhra Praesh, Ina 2 Department of Electrcal Engneerng, Anhra Unersty College of Engneerng (A, Vsakhapatnam, Anhra Praesh Abstract: Electrcty generate from n poer can be hghly arable at seeral fferent tmescales- hourly, aly or seasonally. Annual araton also exsts, but s not as sgnfcant because nstantaneous electrcal generaton an consumpton must reman n balance to mantan gr stablty. The conentonal PI controller may not be eal an robust urng hgh n turbulence. The robust esgn s to fn a controller for a gen system. Hence the H controller s use n orer to reuce the fluctuatons ue to hgh turbulence n n eloctes an a fuzzy logc controller s mplemente such that maxmum poer s elere to the loa. Keyors: Wn energy Conerson Systems, Doubly Fe-nucton Generator, Fuzzy Logc Control, H- nfnty Controller. 1. Introucton Wn poer s the conerson of n energy nto a useful form of energy. Wn poer, as an alternate to fossl fuels, s plentful, reneable, ely strbute, clean, prouces no green house emssons urng operaton an uses lttle lan. Wn poer capacty has expane raply an n energy proucton as aroun 4% of total orl-e electrcty usage. Wn poer s ery consstent from year to year but has sgnfcant araton oer shorter tme scales [1]. Hence n orer to reuce the fluctuatons occurre ue to aratons n n spee aboe or belo the rate spee, H- controller s esgne. Also a fuzzy logc controller s use n orer to extract maxmum poer output. Base on the generate poer an poer output, the fuzzy logc controller ajusts the torue output on the shaft to re the turbne to the esre spee. Fuzzy logc s a poerful an ersatle tool for representng mprecse, ambguous an ague nformaton. It helps us moel ffcult, een ntractable problems. Aantages of fuzzy control are that t s parameter nsenste, proes fast conergence an accepts nose an naccurate sgnals. The fuzzy algorthms are unersal an can be apple retroactely n any system. H methos are use n control theory to synthesze controllers acheng stablzaton th guarantee performance. To use H methos, a control esgner expresses the control problem an then fns the control problem as a mathematcal optmzaton problem an then fns the controller that soles ths optmzaton. H technues hae the aantage oer classcal control technues as they are realy applcable to problems nolng multarate systems. 2. Wn Energy Systems Wn energy conerson systems are ery fferent n nature from conentonal generators, an therefore ynamc stues must be aresse n orer to ntegrate n poer nto the.jsr.net poer system. Moels utlze for steay-state analyss are extremely smple, hle the ynamc moels for n energy conerson systems are not easy to eelop. Dynamc moelng s neee for arous types of analyss relate to system ynamcs: stablty, control system an optmzaton. Moern n turbne generator systems are constructe manly as systems th horzontal axs of rotaton, a n heel consstng of three blaes, a hgh spee asynchronous generator (also knon as nucton generator an a gear box. Asynchronous generators are use because of ther aantages, such as smplcty of constructon, possbltes of operatng at arous operatonal contons, an lo nestment an operatng costs. 1. Moelng of n turbne: the n turbne blaes extract the knetc energy n the n an transform t nto mechancal energy. The poer coeffcent C P can be efne as a functon of the tp spee rato an the blae ptch angle as follos 1 1 c6 x (1 CP(, c1. c2. c. c4. c5 e The poer extracte from the n s gen by 1 PBLADE CP(,... A. (2 2 The rotor torue T can be compute as Paper ID: SUB Lcense Uner Create Commons Attrbuton CC BY T P th efne as BLADE m 1 CP(,... A hle the coeffcents c1-c6 are propose as eual to: C 1 =0.5, C 2 =116, C =0.4, C 4 =0, C 5 =5, C 6 = Doubly fe nucton generator: Wn turbnes usually employ DFIG hang oun rotor nucton generator. The DFIG s one of the machnes hch employ the prncple of m ( (4

2 Internatonal Journal of Scence an Research (IJSR ISSN (Onlne: Inex Coperncus Value (201: 6.14 Impact Factor (201: 4.48 arable spee [2]. Unlke other generators, the DFIG elers poer to the gr through both stator an rotor termnals. The stator s rectly connecte to the gr hle the rotor s connecte to the gr a poer electronc conerters []. Rotor crcut euaton n - frame: r Rrr p r ( e r r (5 R p ( (6 Flux Lnkage expressons: r r r r e r r L L ( L L s ls s m s r s s m r L L ( L L s ls s m s r s s m r L L ( L L r lr r m r s r r m s L L ( L L r lr r m r s r r m s Ls Lm Lls an Lr Lm Llr L ( m m s r L ( m m s r. Controller Implementaton (7 Fuzzy logc controller: An nucton generator reure controller hch ll track n spee n orer to achee opt an thus extract maxmum poer. An MPPT control for each n spee ncreases the output poer n arable spee n turbne system. A fuzzy logc controller s use to mplement MPPT control [5]. The heurstc ay of searchng the maxmum coul be base on a rule base as Fuzzy Meta rule, gen as If the last change n the nput arable (X has cause the output arable (Y to ncrease, keep mong the nput arable n the same recton: f t has cause the output arable to rop, moe t n the opposte recton. In Fuzzy logc controller, there are to nputs ΔP 0 an LΔ r an one output Δ r. In the mplementaton of fuzzy control, the nput arables are fuzzfe, the al control rules are ealuate an combne an fnally the output s efuzzfe to conert to the crspy alue [6]. The rule matrx for the fuzzy logc control s The fuzzy algorthms are unersal an aapte an can be apple n other systems. H Controller Problem formulaton: Intally, the process has to be represente accorng to the follong stanar confguraton A typcal rule can be rea as follos: If ΔP 0 s PM (Poste Meum AND LΔ r s P (Poste, THEN Δ r s PM (Poste Meum..jsr.net The plant P has to nputs W, that nclues reference sgnal an sturbances, an the manpulate arables u. there are to outputs, the error sgnals z that e ant to mnmze, Paper ID: SUB Lcense Uner Create Commons Attrbuton CC BY

3 Internatonal Journal of Scence an Research (IJSR ISSN (Onlne: Inex Coperncus Value (201: 6.14 Impact Factor (201: 4.48 an the measure arables, that e use to control the system. V s use n K to calculate the manpulate arable u. In formulae, the system s [8] z P11 ( s P12 ( s Ps ( u P21 ( s P22 ( s u u K( s u (9 It s therefore possble to express the epenency of z on as: z F ( P, K l 1 Fl ( P, K P P K I P K P (8 ( (11 Therefore, the objecte of H control esgn s to fn a controller K such that (, l F P K s mnmze. The nfnty norm of the transfer functon matrx Fl ( P, K s efne as Fl ( P, K (12 Where γ s the maxmum sngular alue of the matrx Fl ( P, K (j. H control mplementaton: 1. Generator se controller: Fgure (a: Generator se conerter The generator se conerter controls the rotatonal spee of the nucton generator. The rotatonal spee error s use as the nput of the spee(pi controller from hch -axs stator current comman s prouce. The errors beteen the -axs current commans an the actual -axs currents are use as nputs to the current controllers hch prouces the -axs oltage commans V 1 an V [9]. Rertng the generator euatons e obtan the follong euatons 1 1 ( R a 1 e L 1 t L (1 1 ( R a e ( L 1 K t L (14 ( Ra1 e 1 t (15 ( Ra1 e 1 t (16 L Expressng the aboe euatons n the matrx form, the plant matrx s gen belo 1 ( Ra / L ( Ra / L Ra e 0 Ra e 0 (1/ L 0 1 (1/ L 0 0 (1/ L 0 (1/ L 1 1 ( The error sgnal z s as follos z 1 2. (18 The output sgnal y s y (19 L 1 e ( L K 2 e 1 The alues 1 an 2 are consere as sturbances 2. Gr se Inerter:.jsr.net Fgure (b: Gr se conerter Paper ID: SUB Lcense Uner Create Commons Attrbuton CC BY

4 Internatonal Journal of Scence an Research (IJSR ISSN (Onlne: Inex Coperncus Value (201: 6.14 Impact Factor (201: 4.48 In orer to mantan the DC bus oltage V c an the gr oltage V t constant e use gr-se nerter. The -axs current can control the DC bus oltage an to control the gr oltage e use -axs current as shon n fgure. From the follong euatons e can eelop the gr se nerter state space matrx. Lf 2 2 R f 2 e L f t (20 e Lf R f e L f 2 e t (21 ( R / L 0 2 f b f 2 0 ( Rf b / Lf 2 / 0 b Lf b / Lf b / L f 0 b / L f 4 (22 The error sgnal z s gen as z (2 The output y s y (24 L e f L 4 e f 2, 4 are consere as sturbances. Fgure (a: Torue output of the n turbne for fferent n spees. Fgure (b: Torue output of n turbne th an thout Fuzzy logc controller Fg:(a shos the mechancal torue output of n turbne for to fferent spees.e., at =5m/s an =7m/s. From Fg:(b e can see that hen Fuzzy logc controller s connecte to the system, the constant mechancal torue s obtane at a faster rate hen the machne s loae for a partcular n spee, =5m/s hch s use as nput to the nucton generator. Fgure (c: Dfferent n eloctes at fferent tmes System Parameters Blae raus R o =9m Ar Densty ρ=1.205kg/m 2 Stator Resstance 0.02Ω Rotor Resstance 0.015Ω Stator Reactance 0.18Ω Rotor Reactance 0.15Ω Mutual Inuctance Ω. Smulaton Results.jsr.net Fgure (: Dfference beteen electrcal torue generate an the reure alue of nucton generator th controllers. The follong are the graphs corresponng to the outputs of generator se controller an gr se Paper ID: SUB Lcense Uner Create Commons Attrbuton CC BY

5 nerter urng changes n the n elocty. We can obsere that urng the tme beteen 2s to s the H- nfnty controller orks effcently. Internatonal Journal of Scence an Research (IJSR ISSN (Onlne: Inex Coperncus Value (201: 6.14 Impact Factor (201: 4.48 Fgure (e: Dfference beteen electrcal poer output an the reure alue of nucton generator th controllers. Fgure (h: Output poer at the gr se conerter th PI (Conentonal Controller. Fgure (f: Termnal Voltage at the Gr se Controller th PI (Conentonal an Fuzzy Controller. Fgure I: Output poer at the gr se conerter th H- nfnty controller Fgure (g: Termnal Voltage at the Gr se conerter th PI an H-nfnty controller. From Fg:(f an Fg:(g e can obsere that the sturbances n the termnal oltage are reuce th H- nfnty controller hen compare to PI controller..jsr.net From Fg: (h an Fg:( shos the fference beteen the generate poer an the reure poer. We can obsere that the output poer s stable th the propose metho hen compare to the PI controller metho. 4. Concluson In ths paper, a fuzzy logc controller as stue an analyze such that maxmum poer s generate for a partcular n spee an a robust control metho has been presente n orer to reuce the fluctuatons occurre ue to hgh n turbulence n the n energy conerson systems.e., to reuce the mechancal stress on the generator, mproe the stablty n the output poer elere to the loa. References [1] Jasmn Martnez, Moellng an Control of Wn Turbnes, Imperal College Lonon, UK, [2] A. Praeen Varma, K. Bala Chakr, Stuy of Gr Connecte Inucton Generator for Wn Poer Applcatons, Electrcal Engneerng, NIT Rourkela, [] Hector A. Pulgar-Panemal, Peter W. Sauer, Doubly Fe Inucton Machne n Wn Poer Generaton, Unersty of Illnos, US, [4] John Fletcher an Jn Yang, Introucton to Doubly- Fe Inucton Generator for Wn Poer Applcatons, Unersty of Strathclye, Glasgo, UK, Paper ID: SUB Lcense Uner Create Commons Attrbuton CC BY

6 Internatonal Journal of Scence an Research (IJSR ISSN (Onlne: Inex Coperncus Value (201: 6.14 Impact Factor (201: 4.48 [5] Smoes, M.G., Bose, B.K., Spegel, R.J. Fuzzy logc base ntellgent control of arable spee cage n generaton system IEEE Transactons on Poer Electroncs. Vol. 12, NO.1,(January 1997:pp [6] Smoes, M.G., Bose, B.K., Spegel, R.J. Desgn an performance ealuaton of fuzzy logc base arable spee generaton system, IEEE Transactons on Inustry Applcatons. Vol., No.4, (July/August1997, pp [7] T. Kaneko, A. Uehara, T. Senjyu, A. Yona, an N. Urasak, An ntegrate control metho for a n farm to reuce freuency eatons n a small poer system, Apple Energy, ol. 88, no. 4, pp , Apr [8] B. E. Muhano an R. W. Wes, Nonlnear H1 constrane feeback control for gr-nteracte WECS uner hgh stochastcty, IEEE Trans. Energy Conerson (Early Access. [9] Abul Motn Holaer, Naomtsu Urasak, Atsush Yona, Tomonobu Senjyu Ahme Yousuf Saber, A Ne Robust Controller Approach for a Wn Energy Conerson System Uner Hgh Turbulence Wn Velocty, th IEEE Conference on Inustral Electroncs an Applcatons (ICIEA. [10] G. Mokryan, P. Sano, A. Pccolo, an V. Caleraro, A fuzzy controller for mprong Fault Re-Through capablty of n turbnes, 2011 IEEE Internatonal Symposum on Inustral Electroncs, pp , Jun. 27-0, 2011, Gansk, Polan. [11] E. B. Muhano, T. Senjyu, A. Uehara, an T. Funabash, Gan scheule H- control for WECS a LMI technues an parametrcally epenent fee-back part I: moel eelopment funamentals, IEEE Trans. on Inustral Electroncs, ol. 58, no. 1, pp , Jan jsr.net Paper ID: SUB Lcense Uner Create Commons Attrbuton CC BY