Fuzzy Logic Controller Based High Frequency Link AC-AC Converter For Voltage Compensation Using SPWM Technique

Transcription

1 Fuzzy Lgc Cntrller Based Hgh Frequency Lnk AC-AC Cnverter Fr Vltage Cmpensatn Usng SPWM Technque C.Shanmugam 1 PG Schlar/Department f EEE.S.R. Cllege f Engneerng Truchengde, Inda cshanmugam67@gmal.cm A.Maheswar 2 Asst.Prfessr/Department f EEE.S.R. Cllege f Engneerng Truchengde, Inda mahesgce@gmal.cm S.annan 3 PG Schlar/Department f EEE.S.R. Cllege f Engneerng Truchengde, Inda engneerskannan@gmal.cm Abstract In ths paper, an advanced hgh frequency lnk AC-AC Push-pull cyclcnverter fr the vltage cmpensatn s prpsed n rder t mantan the pwer qualty n electrc grd. The prpsed methdlgy can be acheve arbtrary utput vltage wthut usng large energy strage elements. S that the system s mre steadfast and less cstly cmpared wth the cnventnal nverter tplgy. Addtnally, the prpsed cnverter des nt cntan any lne frequency transfrmer, whch reduces the cst further. The cntrl scheme fr the push pull cyclcnverter emplys the fuzzy lgc cntrller based snusdal pulse wdth mdulatn (SPWM t accmplsh better perfrmance n vltage cmpensatn, lke unbalanced vltage harmncs elmnatn. The smulatn results are gven t shw the effectveness f the prpsed hgh frequency lnk AC-AC cnverter and fuzzy lgc cntrller based SPWM technlgy Index Terms Push-Pull cyclcnverter, Fuzzy lgc cntrller (FC and snusdal pulse wdth mdulatn (SPWM. 1 INTRODUCTION A s the rapd ncreasng f the number f the nn-lnear lads nstalled n mdern grd, t becmes a bg cncern t mantan the pwer qualty wthn the acceptable lmts [1]. The develpng f the cncept f mcrgrd makes ths requrement even crucal because that the mcrgrd s much weaker than the cnventnal grd and thus easer t be trubled [2-3]. Mst f the develped slutns t mantan the pwer qualty are qualfed t chse the nverter-based cnverters [4]. Deplrably, the large passve strage cmpnents lke electrlytc capactrs, whch unavdably exst n the nverter-type cnverters, nt nly decrease the relablty f the equpment, but als ncreases the cst. Alternatve appraches are prpsed based n sngle-phase AC-AC tplges r matrx cnverters [5]. The standards-cmplant nverters [6], whch are prncpally desgned fr peratn wth the wder electrcty netwrk, face fundamentally dfferent peratng cndtns n the cnfnes f an slated mcrgrd. These nverters are a key enablng technlgy f dstrbuted generatn n general and f renewables n partcular, ther peratn n an slated mcrgrd s a cncern. Thugh, the matrx based slutns requres cmplex structures and cntrl algrthms whch make them dffcult t handle especally durng the fault cndtn. Whle the sngle-phase based slutns manly fcus n dealng wth the fundamental vltage qualty ssue such as reactve pwer varatn r vltage sag etc. Harmncs prblems are gnred due t the natural lmtatn f the sngle-phase crcut [7]. Recently, a new cncept n the drect AC-AC pwer cnversn feld s prpsed [8] whch apples the Dual Vrtual Quadrature Surces (DVQS vltage synthess thery t the 60 tradtnal AC-AC chppers t acheve the requred vltage utput. Addtnally, nly the balanced grd harmncs are cncerned n all the crcumstances. An mprved methd fr unbalanced vltage harmncs elmnatn s stll mandatry. The gal f the advanced Hgh Frequency Lnk AC-AC Cnverter [9-11] s t apprehend hgh frequency pwer cnversn at the same tme t acheve galvanc slatn by usng a hgh-frequency transfrmer. By applyng the Fuzzy lgc cntrller based snusdal pulse wdth mdulatn t ths type f sngle-phase cnverter, a seres f hgh pwer densty cnverter fr grd vltage cmpensatn can be btaned. In ths paper, an Advanced Hgh Frequency Lnk (AHFL AC- AC cnverter fr vltage cmpensatn s prpsed. The AHFL cnverter can attan arbtrary vltage utput wthut usng any large electrlytc capactrs. Thus, the system relablty can be mprved. Mrever, the cnverter has n lne frequency transfrmer, whch als reduces the cst. The Fuzzy lgc Cntrl (FC scheme based n Snusdal Pulse Wdth Mdulatn (SPWM technlgy s appled t acheve the functn f unbalanced vltage harmncs elmnatn, whch greatly mprved the perfrmance f the vltage cmpensatn. The smulatn results are gven t shws the effectveness f the prpsed AHFL cnverter and SPWM technlgy. 2 ANALYSIS OF ADVANCED HIGH FREQUENCY LIN AC-AC CONVERTER The man crcut f the AHFL AC-AC cnverter desgned fr vltage cmpensatn s shwn n Fg.l(a. The crcut can be dstrbuted nt tw parts. They are, Input push-pull frward cyclcnverter Output push-pull cyclcnverter. Cmpared wth the AC-AC push-pull frward cnverter whch s prpsed and examned n [12], tw addtnal b-

2 drectnal swtches Ss1 and Ss2 are added t the secndary sde crcut f the man crcut. S that, the lne frequency transfrmer s replaced by means f new fur wndngs transfrmer T k whch can nw perate under the hgh frequency swtchng cndtn. The turns fr each wndng f T k are dented as n p1, n p2, n s1 and n s2 respectvely whereas n p1 = n p2 and n s1 = n s2. The turn rat N equals n p1 / n s1. Dfferent frm the crcut apprached n [12], all the b-drectnal swtches are realzed by tw IGBTs cnnected n seres whch s shwn n Fg.l(b. At the same tme, the utput LC flter L and C s mved t the secndary sde t make the crcut smpler. The energy n the leakage nductrs L k1 and L k2 f T k can be recycled by addng ne clampng capactr Cs1. Asscated wth the crcut presented n [12], the large sze f the system s reduced by emplyng the hgh frequency transfrmer. The prpsed crcut has fewer passve cmpnents whch makes the crcut even smaller and easer t analyze. There are fur peratnal mdes fr the AHFL AC-AC cnverter crcut dependng n dfferent plarty f the nput vltage V n and the utput vltage V.The demnstratn f the gate sgnals and the crutal wavefrms f the crcut fr each mde are shwn n Fg.2. chppng f the nput cyclcnverter. The utput cyclcnverter acts lke a rectfer whch s demdulated the AC vltage nt unplarty pulse wave Uab. The utput vltage Vut s then fltered ut by the utput LC flter. An slated AC utput vltage can thus be generated wthut mplementatn f lne frequency transfrmer. The steady state analyss f the crcut s smple as t s essentally attrbuted t buck-type. (a Fg.2 Demnstratn f gate sgnals and crucal wavefrms By applyng the prncple f nductr vlt-secnd balance and usng the small-rpple apprxmatn, the relatnshp f V n and V ut can be gven by: (b Fg.l Prpsed AHFL AC-AC cnverter (a man crcut (b realzatn f b-drectnal swtches In each peratnal mde, ne swtchng perd s dvded nt tw stages, whch are named as the pstve stage and the negatve stage. SPWM methd s appled t each stage t decde the duty cycle f all the transstrs. The duty cycle f the crcut D s defned as fllws: The magntude f D equals the ttal duty cycle f the SPWM vltage U ab n ne swtchng perd T s. It can be fund that the tme average f U ab s V ut, whch nfers that the magntude f V ut s cntrlled by varyng duty cycle D. Furthermre, the varatn range f D s defned as {-1 t 1}. D s negatve when V n and V ut have the ppste plarty. As shwn n Fg.2, the crcut perates n Mde I and IV when D s pstve. It enters the peratn mde II and III when D changes t negatve. The verall way f selectng the swtchng patterns accrdng t dfferent peratnal mdes and stages are gven n Table I. As t nfers n the peratnal strategy, the nput ac vltage s mdulated nt hgh frequency AC vltage Unp1 by the 61 V.. ut Vn D N Based n (1, V ut can be easly cntrlled by varyng duty cycle D. The utput range f V ut s {- V n N t V n N }, whch shws ts b-drectnal cntrl ablty when appled t vltage cmpensatn system. 3 FUZZY LOGIC CONTROLLER FOR AHFL AC-AC CONVERTER (1 The fuzzy cntrl system cnssts f fve parts: fuzzy cntrller, nterface f nput and utput, cntrl bect, execute nsttutn and sensrs [13], whch actually translates the knwledge and experence f expert nt the cntrl law. Because FC s nt desgned based n the mathematcal analyss f a prcess mdel, MATLAB/ SIMULIN and Fuzzy Lgc Tlbx are used fr smulatn analyss. The actual nstantaneus utput vltage s sensed, sampled and cmpared wth snusdal reference value t create the errr vltage. Dscrete errr vltage E(k and ts change f errr Ec(k are prcessed by the FC thrugh fuzzfcatn, fuzzy nference and defuzzfcatn peratns. The change f cntrl sgnal Δu(k as the utput varable f prmary FC s added t the cntrl sgnal, U(k t gve a updated value f swtchng angles t cmpensate prperly wth

3 any ladng varatn. In the FC system, weght factr e, c and scalng factr u are very mprtant t the statc and dynamc perfrmance. The effect f the gan settngs fr a cnventnal PI cntrller n a clsed lp system s related t the scalng factrs adustment n the FC, whch can be apprxmated as a actual PI cntrller. Referrng t the cnventnal ntegral dgtal PI cntrller. The cntrller s desgned as a duble clsed-lp f Output vltage nstantaneus FC and nductr current P Cntrl, whch s shwn n Fg.2. As the nput varatns f PI-type prmary fuzzy cntrller and PD-type assstant fuzzy cntrller, E and EC have the defntn f errr and the change f errr respectvely [8]. TABLE II. PRIMARY FC RULES u( k e( k e( k Referrng t FC presented n [14]. Relatng (2 and (3, P u( k Ec( k E( k U C E P C and I U Referrng t cnventnal PI cntrl experence [15], the fllwng cnclusns can be ganed: A hgher value f e wll cause a lng transtn prgress r even an versht. On the cntrary, a smaller e wll result n a pr dynamc respnse and a large system errr. Increscent c can make the cntrller senstve, whch wll avd versht f the system utput and brng ut a slw dynamcs. Otherwse, a large versht r even a surge wll ccur. The value f u wll nfluence drectly the utput scale f cntrller. By reducng u, a steady utput can be acheved. On the ther hand, a large u makes fr a prper dynamcs.a cmprmse shuld be carred when selectng an apprprate u. In Fg.3, a fuzzy cntrller based n scalng factr selfadustng nlne s desgned. The assstant fuzzy cntrller s ntrduced t mdfy the scalng factr f prmary fuzzy cntrller fr better rbust dependng n varus lad features. The basc rules f assstant fuzzy cntrller are shwn as fllws. Scalng factr u shuld be reduced fr a small utput versht and shrt rse-tme when errr E s large and has the nverse sgn wth the change f errr, EC. On the cntrary, u shuld be ncreased when E and EC has the same sgn, because system utput s drawng away wth reference at ths pnt. On the ther hand, when E has a large value, scalng factr u shuld have a large change range. It shuld be reduced f system utput draws away frm reference after drawng n t. Ths methd s n fact a gan-varable nnlnear cntrller whch s unattached wth mdel [16]. Rules f prmary FC and assstant FC are shwn n Table II and Table III respectvely. Fg.3 Blck dagram f Fuzzy cntrller I E U (2 (3 (4 62 EC/E NB NM NS ZE PS PM PB NB NB NB NB NB NM NS ZE NM NB NB NB NM NS ZE PS NS NB NB NM NS ZE PS PM ZE NB NM NS ZE PS PM PB PS NM NS ZE PS PM PB PB PM NS ZE PS PM PB PB PB PB ZE PS PM PB PB PB PB TABLE III ASSISTANT FC RULES EC/E NB NM NS ZE PS PM PB NB VB VB VB B M SM VS NM VB VB B B BM SM S NS VB BM NM B VB S S ZE SM M BM VS M BM SM PS S SM S VB B BM VB PM S SM BM B B VB VB PB VS SM M B VB VB VB They are all dvded nt seven fuzzy subsets frm [-8, +8]: {NB, NM, NS, Z, PS, PM, PB}. As shwn n Fg.3, ther membershp functns have the same gemetry f asymmetrc Trangle [9]. Δu as the utput varatn f prmary fuzzy cntrller s als dvded nt seven subsets, whch s nt lke α, the utput f assstant fuzzy cntrller. α s dvded nt seven fuzzy subsets frm [0,1], {VS, S, SM, M, BM, B, VB}. But they have the same membershp functns f symmetrcal trangle. The nference lgc f MAX-MIN methd s emplyed n tw fuzzy cntrllers, smlarly the defuzzfcatn methd f centrd frmula s shwn n (4 [9]. u n 1 n ( u u 1 ( u 4 SINUSOIDAL PULSE WIDTH MODULATION TECHNOLOGY Tradtnally, the sngle-phase AC-AC cnverter s cnsdered as cannt utput the vltage wth arbtrary frequency and phase. In rder t break the lmtatn, DVQS vltage synthess cncept s prpsed n [7]. Based n ths cncept, the Even Harmncs Mdulatn (EHM scheme s als prpsed n [7] t generate the requred cmpensatng sne wave utput [7-10]. Hwever, the EHM scheme stll has ts wn lmtatn such that the frequency f the utput vltage can nly be the ntegral multple f the lne frequency. Furthermre, nly the balanced grd faults are cncerned n all the scenars n [17-19]. In ths paper, Snusdal Pulse Wdth Mdulatn (SPWM technlgy s prpsed t replace the EHM scheme and mprve the perfrmance f AHFL cnverter when dealng wth the unbalanced harmncs and grd (5

4 fault by generatng the unbalanced cmpensatng vltage utput. The basc cncept f SPWM can be descrbed as fllws. At frst, the three-phase nput grd vltage V m s assumed as the balanced pure sne n pstve sequence, whch s gven by: V V snt na m V V sn ( t 120 nb m V V sn ( t 120 nc m (a Membershp functns f E and EC (6 D D D a0 0a b0 0b c0 0c Substtute (6 and (7 t (1, the utput vltage f the cnverter n each phase s V V. D. N V snt uta0 na a0 0a m V V. D. N V sn ( t 120 utb0 nb b0 0b m V V. D. N V sn ( t 120 utc0 nc c0 0c m It can be cncluded n (8 that the utput vltage s n phase wth the nput vltage as well as the frequency s the same. The ampltudes are dfferent f a b c. It s used as vltage varatn cmpensatn by cntrllng the value, whch s the cmmn cntrl strategy fr the AC-AC cnverters applyng n vltage cmpensatn [5-9]. 4.2 Generatn f vltage n pstve sequence The SWM scheme fr generatng the pstve sequence vltage fr cmpensatn s t add a seres f negatve sequence snusdal waves t the mdulatn wave f D. The ampltude f the snusdal waves s expressed as and the crrespndng angular frequency and phase are ω, and ϕ respectvely. The mdulatn wave f D fr cnverters n each three-phase s the summatn f all the snusdal cmpnents, whch s gven by: D sn( t ap D sn( t 120 bp D sn( t 120 cp (7 (8 (9 Substtute (6 and (9 t (1, the utput vltage f the cnverter n each phase s: (b Membershp functn f Δu Fg 4. Shape f membershp functns fr SAFC Where V m s the ampltude f V n and the angular frequency ω can be 2πf. As ndcated n DVQS cncept [10], the duty rat D f the AC-AC cnverter s n need t fx but can add a specfed mdulatn wave whch may vary wth tme. The prducts f the nectn can nt nly be the fundamental frequency utput but als the harmncs utput. Therefre, the vltage synthess prcess f SWM has three steps. Frstly, the desred vltage utput s separated nt several decupled cmpnents wth dfferent frequency and sequence, ncludng the fundamental cmpnents, harmncs cmpnents and even the cmpnents wth the fractnal multple f the lne frequency. Fllwng ths, several specfed mdulatn waves are mplemented t the AC- AC cnverter t generate each requred cmpnent utput. At last, the utputs are added tgether t refrm the desred vltage utput. The fllwng parts are t fgure ut hw t decde the specfed mdulatn waves used fr vltage synthess. Generally, the desred vltage s separated nt the fundamental vltage, the vltage n pstve sequence and the vltage n negatve sequence. 4.1 Generatn f fundamental vltage The SWM scheme fr generatng the fundamental vltage s t add the fxed DC cmpnent t the mdulatn wave f D whch s expressed as: V V. D. N ut _ ap na ap 1 1 V cs ( t cs ( t 2 2 V V. D. N ut _ bp nb bp 1 1 Vm cs ( t 120 cs ( t 2 2 (10 V V. D. N ut _ cp nc cp m 1 1 Vm cs ( t 120 cs ( t 2 2 It can be fund that the utput vltage cnssts f tw quadrature cmpnents. The frst harmnc cmpnent n pstve sequence has the angular frequency equal t ω - ω and the phase equal t ϕ. The ampltude, phase and frequency f ths cmpnent are all cntrllable by settng prper ω, and ϕ. In rder t keep ths cmpnent n pstve sequence, the cndtn ω ω >0 shuld be satsfed. The secnd harmnc cmpnents are n zer sequence, whch means that t cannt prpagate n the three-phase system. As a result, after the mplementatn f the negatve sequence snusdal waves t the mdulatn wave f D a seres f new cntrllable vltage utputs n pstve sequence can be synthessed n the utput vltage. Als, the by-prducts can be elmnated wthut addng addtnal flters. 4.3 Generatn f vltage n negatve sequence Dfferent frm the pstve sequence vltage generatn, under ths cndtn, negatve sequence snusdal waves wth ω 63

5 ω < 0 are mplemented t the mdulatn wave f D. The expressn fr D s gven by, D sn( t an D sn( t 120 bn D sn( t 120 cn If ω < 0, (10 s changed t D sn( t an D sn( t 120 bn D sn( t 120 cn whch represent a pstve sequence snusdal wave. Despte f the zer sequence cmpnents, negatve sequence cmpnents are ncluded n the utput vltage by mdulatn, whch has the angular frequency equal t ω - ω, the phase equal t φ and the ampltude s V m as well. 4.4 Cmbnatn f utput vltage The fnal utput s gven n (13. It s smply t add all the mdulatn waves tgether t be the mdulatn wave D fr the AC-AC cnverter. The zer cmpnents are excluded n the fnal results f the utput vltage. It s nferred n (13 that by applyng the SWM technlgy, arbtrary vltage utput s realzed usng the sngle-phase based AC-AC cnverter. Partcularly, the frequency range f utputs are (0,, whch means that the utput vltage s nt lmted t the ntegral multple f the lne frequency. As a result, cmpared t EHM, the prpsed strategy s mre flexble whch can handle all the harmncs vltage generatn ncludng unbalanced vltage and can be ptentally used n AC applcatns such as mtr drve etc. 5 CONFIGURATION OF VOLTAGE COMPENSATION SYSTEM One f the typcal applcatns fr the prpsed AHFL cnverter wth SWM scheme s the vltage cmpensatn system. Fg.5 shws the system cnfguratns fr vltage cmpensatn. (11 ( Vut _ an Vna. Da 0 Dap Dan. N 0aVm sn ( t Vm cs ( t Vm cs ( 2 2 t 1 1 Vut _ bn Vnb. Db 0 Dbp Dbn. N 0bVm sn ( t 120 Vm cs ( t 120 Vm cs ( t Vut _ cn Vnc. Dc 0 Dcp Dcn. N 0cVm sn ( t 120 Vm cs ( t 120 Vm cs ( t The vltage at the PCC s dstrted by the nnlnear lad such as dde-rectfer wth resstance-capactance lad. The nnlnear lad can be cnnected t ether the three-phase r sngle-phase. Thus the vltage harmncs at PCC culd be unbalanced. At the same tme, ne three-phase crtcal lad requres pure sne vltage nput. Three ndvdual AHFL cnverters are appled t each phase t realze vltage cmpensatn functn. The cnverter s placed between the grd and the crtcal lad, whch can be cnsdered as a cntrllable vltage surce t nect a cntrllable cmpensatn vltage n seres wth the grd vltage t cmpensate fr the harmncs and vltage varatns. The nput pwer f the AHFL cnverter s drawn frm the grd sde. The nput nductr L s added t mnmze the swtchng harmncs superpsed t the grd. The relatnshp between the system nput vltage V sys_n and utput vltage V sys_ut s gven by: V sys _ uta V sys _ na Vuta V sys _ na Da Vsys _ ut Vsys _ utb Vsys _ nb Vutb Vsys _ nb.1 Db N V sys _ utc V sys _ nc V utc V sys _ nc D c Where V sys_n s als the nput vltage f the AHFL cnverter and the cmpensatng vltage V ut s the utput vltage f the AHFL cnverter. 6 SIMULATION RESULT (14 Smulatn studes are carred ut n MATLAB/Smulnk t valdate the prpsed AHFL cnverter as well as the SPWM scheme. The specfcatn f the system are gven by: V sys_n : 220 V; V sys_ut : 220V; V lne : 380V; P ut : 3kW; f s : 10kHz; C : 3 μf; C : 5 μf; C s1 : 1 μf; L : 2mH; L : 0.68mH. Three 1 mh nductrs L s are cnnected n seres wth the utput f three sne vltage surces n rder t smulate a weak grd. The Smulnk dagram s shwn n fg.6. The dynamc perfrmances f the Cnventnal and Prpsed methds are shwn n fg.7 & fg.8 respectvely. 7 CONCLUSIONS In ths paper, The AHFL AC-AC cnverter fr vltage cmpensatn s prpsed. The AHFL cnverter has the Fg.5 Typcal system cnfguratn wth prpsed IHFL AC-AC cnverter fr vltage cmpensatn 64 Fg. 6 Smulnk Dagram f Prpsed AHFL AC-AC Cnverter Scheme

6 Fg.7. Smulatn results f nput and utput lne vltage and current fr cnventnal methd Fg.8. Smulatn results f nput and utput lne vltage and current fr prpsed methd (13 [3] W. Fe, 1. L. Duarte and M. A. M. Hendrx, "Grd-Interfacng Cnverter Systems Wth Enhanced Vltage Qualty fr Mcrgrd Applcatn - Cncept and Implementatn," Pwer Electrncs, IEEE Transactns n, v1.26, pp , [4] O. S. Senturk and A. M. Hava, "Perfrmance Enhancement f the Sngle-Phase Seres Actve Flter by Emplyng the Lad Vltage Wavefrm Recnstructn and Lne Current Samplng Delay Reductn Methds," Pwer Electrncs, IEEE Transactns n, v1.26, pp , [5] A. Dasgupta and P. Sensarma, "Vltage sag mtgatn usng a drect Matrx Cnverter," n Prc. Pwer Electrncs, Machnes and Drves (PEMD 2012, 6th IET Internatnal Cnference n, pp [6]. Basu, R.. Gupta, S. Nath, G. F. Casteln,.. Mhapatra and N. Mhan, "Research n matrx-cnverter based three-phase pwer-electrnc transfrmers," n Prc. Pwer Electrncs Cnference (IPEC, 2010 nternatnal, pp [7] D. M. Dvan and J. Sastry, "Vltage Synthess Usng Dual Vrtual Quadrature Surces A New Cncept n AC Pwer Cnversn," Pwer Electrncs, IEEE Transactns n, v1.23, pp ,2008. [8] A. Prasa and D. Dvan, "Cntrl f Dynamc Capactr," ndustry Applcatns, IEEE Transactns n, v1.47, pp , Fg.9. Smulatn results f harmnc spectra f utput lne current fr Prpsed methd advantages such as n large electrlytc capactrs and n lne frequency transfrmer. S that the cst f the system s reduced and the relablty s mprved. The new prpsed SPWM technlgy can be used t acheve the functn f unbalanced vltage harmncs elmnatn t ncrease the perfrmance f the vltage cmpensatn. The Fuzzy lgc Cntrller prpsed n ths paper has a smple desgn prgress n need f exact mathematcs mdel f AC-AC Cnverter and can perate autmatcally wthut man-made effect. It prvdes nsenstvty t plant-parameter varatns and external dstrbutn such as makng fr vercmng perturbatns caused by Nn-lnear lads. The smulatn results are shw the effectveness f the prpsed AHFL cnverter and SWM technlgy. REFERENCES [I] V. hadkkar, "Enhancng Electrc Pwer Qualty Usng UPQC:A Cmprehensve Overvew," Pwer Electrncs, IEEE Transactns n, v1.27, pp , [2] D. Crnfrth, T. Mre and S. Sayeef, "Challenges and pprtuntes fr nverters n mcrgrds," n Frc. IECON th Annual Cnference n IEEE Industral Electrncs Scety, pp [9] H. rshnaswam and V. Ramanarayanan, "Cntrl f hghfrequency AC lnk electrnc transfrmer," Electrc Pwer Applcatns, IEEE Prceedngs -, v1.l52, pp , [10] M. D. Manrekar, R. eferndrf and G. Venkataramanan, "Pwer electrnc transfrmers fr utlty applcatns," n Prc. Industry Applcatns Cnference, Cnference Recrd f the 2000 IEEE, pp [11] P. M. Espelage and B.. Bse, "Hgh-Frequency Lnk Pwer Cnversn," ndustry Applcatns, IEEE Transactns n, vi.ia- 13, pp , [12] C. L, Y. Deng, H. Peng, X. He, W. L and Y. Wang, "Partal pwer cnversn devce wthut large electrlytc capactrs fr pwer flw cntrl and vltage cmpensatn," IEEE Transactns n Pwer Electrncs, v1.27, pp , [13] Lu Lng, Zhu Yng-peng; Xu Jn-bang, Wan Shu-yun, Parameters self-adustng fuzzy PI cntrl wth repettve cntrl algrthms fr 50 Hz n-lne UPS cntrlled by DSP Industral Electrncs Scety, IECON th Annual Cnference f IEEE Vl 2,2-6 (2: , Nv [14] Azl, N.A. Nng, W.S. Applcatn f fuzzy lgc n an ptmal PWM based cntrl scheme fr a multlevel nverter Pwer Electrncs and Drve Systems, PEDS The Ffth Internatnal Cnference n Vlume 2, 17-20,pp: ,Vl.2 Nv [15] L.Chushan, D.Van, L.Zb, T.Yng, L.Wuhua, H.Xangnng and W.Yusheng, Inslated Hgh Frequency Lnk AC-AC Cnverter based n Snusdal Wave Mdulatn Technlgy fr Vltage Cmpensatn, IEEE Transactns n Pwer Electrncs, pp , Aug [16] D.SUN, H. Y-kang and Z.Da-we, Self-adaptng fuzzy cntrl f SRM based n ts nnlnear mdel,advanced Technlgy f Electrcal Engneerng and ENERGY,2001(4:9-13

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