Design, modeling and analysis of a brushless doubly-fed doubly-salient machine for electric vehicles

Transcription

1 itle Deign, modeling nd nlyi of bruhle doubly-fed doubly-lient mchine for electric vehicle Author() Fn, Y; Chu, K Cittion Conference Record - I Annul eeting (Ieee Indutry Appliction Society), 005, v. 4, p Iued Dte 005 URL Right 005 IEEE. Peronl ue of thi mteril i permitted. However, permiion to reprint/republih thi mteril for dvertiing or promotionl purpoe or for creting new collective work for rele or reditribution to erver or lit, or to reue ny copyrighted component of thi work in other work mut be obtined from the IEEE.; hi work i licened under Cretive Common Attribution-NonCommercil-NoDerivtive 4.0 Interntionl Licene.

2 Deign, odeling nd Anlyi of Bruhle Doubly-Fed Doubly-Slient chine for Electric Vehicle Ying Fn, K.. Chu Deprtment of Electricl & Electronic Engineering he Univerity of Hong Kong Hong Kong, Chin Abtrct hi pper preent new three-phe 1/8-pole bruhle doubly-fed doubly-lient (BDFDS) mchine for ppliction to electric vehicle. he key i to deign, modeling, nlyze nd control the propoed BDFDS mchine. he output power eqution i nlyticlly derived, nd the initil clcultion of mchine dimenion nd prmeter re lo dicued. By uing finite element nlyi, the field ditribution of the BDFDS mchine t different lod nd field current re obtined, in which the mgnetic turtion nd the coupling between rmture current flux nd field current flux re conidered; moreover, the ttic chrcteritic of the propoed mchine re given. Bed on the ttic chrcteritic, the ytem mthemticl model h been etblihed. Hence, the evlution of ytem performnce i conducted by computer imultion in which the imultion model combine the mchine with 3-phe hlf-bridge converter. A 1/8-pole BDFDS mchine i deigned nd built for exemplifiction, nd drive ytem employing thi new mchine h been developed nd invetigted experimentlly. Experimentl reult re lo given to verify the vlidity of the theoreticl nlye. Keyword-Doubly lient motor; bruhle mchine; electric vehicle. I. INRODUCION With ever increing concern on our environment, the development of electric vehicle (EV) h tken on n ccelerted pce. o enble EV directly competing with goline vehicle, our gol of the EV motor drive re to purue high efficiency over wide peed rnge, high power denity, high controllbility, high relibility nd mintenncefree opertion. he torque peed chrcteritic of DC motor re ttrctive for EV propulion, but owing to the drwbck of low efficiency, low power denity, well the need of mechnicl commuttor nd crbon bruhe, DC motor re being upereded by induction motor, permnent mgnet bruhle motor (PBL) [1]-[] nd witched reluctnce motor (SR). oreover, the doubly lient permnent mgnet (DSP) motor h recently been propoed which combine the dvntgeou feture of both PBL nd SR motor [3]-[7]. Neverthele, the DSP motor till uffer from the drwbck imilr to tht of the PBL motor drive, nmely the uncontrollble P flux t high peed opertion nd high P cot. Previou reerche in the doubly lient permnent mgnet (DSP) motor drive hve uggeted tht the P excittion cn be directly replced by DC field winding. Bing on thi ide, the new motor will conit of two type of ttor winding which re polyphe rmture winding nd DC fielding, oclled the bruhle doubly-fed doubly-lient (BDFDS) motor drive. Since the DC current flowing through the field winding cn be independently controlled, the BDFDS motor drive will not only olve the fundmentl problem of the DSP motor drive, but lo offer the poibility to on-line optimize the efficiency. he purpoe of thi pper i to deign nd nlyi threephe 1/8-pole bruhle doubly-fed doubly-lient (BDFDS) mchine for electric vehicle. Section II will give brief introduction of the BDFDS mchine. he deign procedure will be decribed to decide the initil dimenion nd prmeter of thi mchine in Section III. Section IV will be devoted to the electromgnetic nlyi nd ytem modeling. he finite element nlyi (FEA) i pplied to nlyze the ttic chrcteritic of the mchine, in which the mgnetic turtion nd the coupling between rmture current flux nd field current flux re conidered. In Section V, the imultion which the converter i lo included in the whole ytem will be dicued. he implementtion nd experimentl verifiction will be given in Section VI. Finlly, concluion will be drwn in Section VII. II. ACHINE DESCRIPION AND OPERAING PRINCIPLES Fig. 1() depict three-phe 1/8-pole BDFDS mchine, which conit of two type of ttor winding which re DC field winding nd three-phe concentrted rmture winding. It h the me tructure SR motor with twelve lient pole in the ttor nd eight lient pole in the rotor. Since there re no P, no bruhe nd no winding in the rotor, it offer very imple rotor tructure nd the cpbility to run t very high peed. Becue the DC current flowing through the field winding cn be independently controlled, thi BDFDS mchine will not only olve the fundmentl problem of the hi work w upported nd funded in prt by the Reerch Grnt Council of Hong Kong nd the Reerch nd Conference Grnt Committee of he Univerity of Hong Kong. IAS /05/$ IEEE

3 DSP motor, but lo offer the poibility to on-line optimize the efficiency. he operting wveform of field flux linkgeψ nd phe current i with repect to the rotor poition θ re hown in Fig. 1(b). When the rotor pole i entering the zone of conductive phe, the flux of the phe winding i increing. By pplying poitive current to the winding, the poitive torque will be produced. When the rotor pole i leving the ttor pole from the ligned poition, the flux i decreing, nd negtive current when the P flux i decreing. he poitive torque i lo produced by pplying negtive current to the winding. herefore, the two poible torque producing zone re fully utilized. III. DESIGN Hving vluble reerch experience in the DSP motor [3], the output power P o eqution of the BDFDS mchine cn be deduced : N r o = kd keki A Bδ nηdilef (1) 10 N P 0.87π where P o i the output power, N nd N r re the ttor nd rotor pole number, repectively, k d i the flux lekge fctor, k e = U E i the rtio of voltge to bck EF; Generlly, the rnge of k d nd k e re preented : reltionhip mong ttor pole number number N r nd phe number m re given by: N N r = mk = N ± k N, rotor pole where k i poitive integer. When the mchine run t the peed of n, the commutting frequency of ny phe i f = ph N rn 60. o minimize the witching frequency nd hence the lo in power witche well the iron loe in pole nd yoke, the number of rotor pole hould be elected mll poible. herefore, the number of rotor pole i uully le thn tht of ttor pole. o mke the motor cpble of trting itelf in either forwrd or revere direction, the phe number hould be equl to or greter thn three. hu, N N r = 6/ 4, 8/6 nd 1/8 re poible configurtion of the BDFDS mchine. A compred to the three-phe 6/4- pole one, the three-phe 1/8-pole BDFDS mchine poee horter flux pth in yoke reulting in le mgnetic potentil drop nd iron loe. oreover, becue the flux per mgnetic pole i hlved in 1/8-pole mchine, the wih of both ttor yoke nd teeth i lmot one-hlf of thoe of 6/4- (5) k k d e = 0.9 ~ 0.93 = 1.5 ~.0 k i i the rtio of current mplitude I m to rm vlue of current I, it cn be computed : rm () I rm 1 1 i = I m w = I m 0 θcr 3 = θ = I 3 where i the running cycle, i i the intntneou phe current. In (3), θ w θ cr = 1/ 3 i bed on the operting principle hown Fig. 1(b). hu m (3) () I m 3 k i = = (4) I rm A i the electric loding of ttor, it cn be choen in the rnge of 100 ~ 300 A/cm; B δ i the ir-gp flux denity, it i uully elected 1.5 ; n i the rted peed in 1500rpm, η i the mchine efficiency in 8%, D i i the inner dimeter of ttor, l ef i the effective tck length. here i wide rnge of poible combintion of phe winding, ttor nd rotor pole number tht cn be choen for BDFDS mchine deign. In ccordnce with the bic opertion principle of the BDFDS mchine, the generl (b) Figure 1. hree-phe 1/8-pole BDFDS mchine. () Configurtion.(b) Operting principle. IAS /05/$ IEEE

4 pole mchine. hi llow greter inner ttor dimeter nd hence greter rotor dimeter. herefore, higher torque denity cn be chieved. Furthermore, le wih of ttor teeth reult in horter end prt of phe winding, leding to le copper conumption nd reitnce of winding. Hence, higher efficiency cn be expected for the BDFDS mchine. IV. FINIE ELEEN ANALYSIS AND SYSE AHEAICAL ODEL A. Finite Element Anlyi By uing the finite element method (FE), the ttic chrcteritic of the BDFDS mchine re nlyzed. For implicity, the two-dimenionl (D) FE i dopted to determine the mgnetic field ditribution of the BDFDS mchine. Due to the periodic mchine configurtion, the region of interet for finite element nlyi i hlf of the whole mchine cro-ection. he mgnetic field ditribution of the propoed BDFDS mchine t different rotor poition nd lod re nlyzed, Fig. () how the field produced by field current only nd Fig. (b) how the field produced by rmture current of phe B only. It cn be found tht the flux pth i concentrted on the overlpping re between the ttor nd rotor teeth. Bed on the FEA reult, the chrcteritic of the BDFDS mchine, including the field flux linkge, elfinductnce, mutul inductnce, bck EF cn be obtined. he flux linkge which vrie with the rotor ngle nd the field current i hown in the Fig. 3. oreover, the imulted inductnce chrcteritic re obtined hown in Fig. 4. where [,, ] b c U = RI + dψ (6) U = u u u, u i the mtrix of the pplied f voltge, u, ub, uc re the phe voltge nd u f i the field I = i i i, i i the mtrix of pplied current. voltge. [,, ] i i, i b c, b c re the phe current nd f [ r, r, r r ] R, f i i the field current, = dig b c f i the mtrix of reitnce, r rb, rc, re the rmture winding reitnce nd r f i the field winding reitnce, the mtrix of inductnce i given : Figure 3. Simulted flux linkge uing FE. B. Sytem themticl odel he ytem mtrix eqution decribing the three-phe 1/8-pole BDFDS mchine i expreed : () () (b) Figure. Simulted mgnetic field ditribution uing FE. () No-lod. (b) Armture current only. (b) Figure 4. Inductnce chrcteritic uing FE. () Self-inductnce. (b) utul inductnce. IAS /05/$ IEEE

5 where bb L b c f b Lbb bc bf L = (7) c cb Lcc cf f fb fc L ff L, L, L re the elf-inductnce of rmture cc winding nd L ff i the elf-inductnce of field winding.,,,,, re the mutul inductnce b b c c bc cb between the rmture winding, f, f, bf, fb, cf, fc re the mutul inductnce between the rmture winding nd field winding. Ψ = LI i the mtrix of flux linkge, repectively. herefore, d Ψ = L ( di ) + ( dl ) I. (8) hu, the ytem eqution (6) cn be rewritten : di 1 1 dl = L U L ( R + ωr I dθ ) where the ω r i the rotor mechnicl peed, θ i the rotor poition which i mechnicl ngle. he energy tored in the mgnetic field under current I cn be expreed W f = I LI. When the iron lo i neglected, the input power of the mchine cn be decribed : I U = I RI + I = I = I L 1 RI + I 1 RI + I di + dl dl dθ dl I I d 1 I + ( I d 1 Iωr + ( LI ) I LI ) (9). (10) Eqution (10) cn be rewritten Pin = Pcu + ω r + dwf. herefore, the torque cn be clculted by: 1 dl = I I. dθ (11) V. SIULAION RESULS A. Converter Configurtion nd control trtegy o upply the BDFDS mchine, bipolr converter topology i preferred o to mke bi-directionl current opertion poible. hu, there re two converter topologie in which the phe current cn be controlled individully for bidirectionl opertion, nmely the full-bridge converter nd the hlf-bridge converter with plit cpcitor. he hlf-bridge converter i dopted hown in Fig. 5, becue it minimize the number of power device nd ech phe current cn be independently controlled. he connection between the midpoint of the plit cpcitor nd the neutrl of motor winding, hown by the dotted line in Fig. 5, i uully necery to ccommoe the dditionl current during the commuttion period. In order to produce mximum output nd incree the ytem efficiency, the turn on ngle i pecilly choen to ure tht the phe current i the mximum t the point when the phe flux linkge trt to incree. he turn off ngle i elected to get the mximum vible torque. According to the flux linkge profile of ech phe hown the upper trce ( ψ, ψ b, ψ c ) in Fig. 6, the control logic for ech witch in the converter i portryed the lower trce ( S 1, S, S3, S4, S5, S6 ) in Fig. 6. At ny intnt in time two phe re energized nd one phe i off. he commnd current in ech phe re decribed Fig. 7, in which θ e i the electricl ngle nd the reltion between the electricl ngle nd mechnicl ngle i θ = N rθ. e wo operting mode re imulted. One i the low peed opertion which the hyterei current control i ued for contnt torque opertion nd the other i the high peed opertion which the ingle pule control trtegy i performed for the contnt power opertion. B. Simultion Reult Bed on the ttic chrcteritic, uch elf-inductnce, mutul inductnce nd flux linkge hown in Fig. 3 nd Fig. 4, obtined from FEA, the motor performnce re imulted uing tlb/simulink. he ue of tlb/simulink environment tke dvntge of ey progrmming, high flexibility nd plentiful toolboxe. he correponding power ytem block i ued to imulte the inverter nd BDFDS mchine together. In imultion, the current re olved by (9) fter the voltge re determined by the rotor poition nd witching mode. he intntneou torque cn be clculted by (11) when the current hve been worked out. he control trtegy for three-phe BDFDS mchine i bed on the bove nlyi, while the torque control i chieved by chnging the current reference. he correponding control logic of thoe power witche i bed on the encoder feedbck ignl which reflect the rotor poition. he wveform of totl verge torque v, the intntneou torque int, the phe current i, nd the flux φ under tedy tte re imulted. Fig. 8 how thee wveform which the BDFDS mchine i operted under the rted lod of 4.70 Nm t peed of 600 rpm, it cn be found the v keep contnt nd the current mplitude i effectively controlled. Fig. 9 how thee wveform t high peed of 1800 rpm, it cn be een the v reduced to relize the contnt power opertion. he imulted no-lod EF wveform t rted peed i hown in Fig. 10. VI. IPLEENAION AND EXPERIENAL VERIFICAION For verifiction, 1/8-pole BDFDS mchine prototype hown in Fig. 11, with the rting of 750 W nd 1500 rpm, i deigned nd built for verifiction. A drive ytem employing IAS /05/$ IEEE

6 thi new motor h been built nd invetigted experimentlly in the electric drive lb of he Univerity of Hong Kong. he experimentl et-up nd it ubytem re hown in Fig. 18 nd Fig. 19. Figure 7. hree-phe commnd current. Figure 5. Sytem configurtion of the BDFDS mchine. Figure 8. Simultion reult of the BDFDS mchine under rted lod t 600 rpm. Figure 6. Flux linkge of three-phe winding nd control logic of the witche in the hlf-bridge converter. Figure 9. Simultion reult of the BDFDS mchine t the peed of 1800 rpm. IAS /05/$ IEEE

7 re meured. Fig. 13 how the meured phe current nd phe voltge of the hyterii control opertion, repectively. he line to line voltge between two phe i hown in Fig. 14. Furthermore, both the phe current nd totl torque re meured t the me condition, the torque i teted by torque enor 34FN under tedy tte, Fig. 15 how thee wveform. Alo, it cn be clculted from Fig. 15 tht the torque ripple obtined from the meured torque wveform i bout 6%, it i very mll, becue in the tedy tte t low peed, the current mplitude i controlled to keep contnt. Figure 10. Simulted no-lod EF wveform t rted peed. A. Decription of the Drive Sytem otor: he correponding key of the motor re lited in ble I. Converter nd Controller: o verify the performnce of the motor, the hyteri current control circuit nd three-phe hlf-bridge converter hown in Fig. 5 w built nd ued in the experiment drive. he IGB module re ued witching device in the converter. In ccordnce with the opertion principle of the BDFDS mchine, the phe winding hould be turned on or off t the pecific rotor poition. Hence, the rotor poition informtion i indipenble for the proper opertion of the BDFDS mchine. For the mchine drive ytem developed in thi pper, poition re meured by n opticl encoder which produce pule per revolution nd mounted with the mchine in the coxil wy by coupler hown in the right prt of Fig. 11. he current i regulted by hyterei control t low peed nd by ingle pule control t high peed. o implement the current control, controller bed on dspace DS1104 R&D controller bord w built. he input commnd to the controller re the phe current limit, turn on ngle, nd turn off ngle nd the feedbck ignl re rotor poition nd phe current. he phe current re meured by LE hll effect current enor LA5-NP, it meure bi-directionl current up to 5 A rm from DC to 150kHz, furthermore, it cn be mounted on the circuit bord nd the current rnge cn be elected. Bed on the control commnd nd the feedbck current nd rotor poition, the controller produce the driving ignl which re trnmitted to the gte driver of the converter. Lod: he lod of the teted mchine i provided by DC dynmometer. he operting point of the teted BDFDS mchine cn be chnged by regulting the field current nd the electric lod - PLZ1003WH of the DC dynmometer. B. Experimentl Reult Fig. 1 how the meured no-lod EF wveform t 1500 rpm, it cn be found tht they cloely gree with the imulted wveform hown in Fig. 10. Under the rted lod of 4.70 Nm nd t the peed of 600 rpm, the phe current, phe voltge nd line to line voltge he phe current nd the relted gting ignl of witche re lo meured nd Fig.16 nd Fig.17 hown. It i obviou tht the meured current wveform hown in Fig. 13 nd Fig.15 ~ Fig.17 cloely gree with the imulted current wveform hown in Fig. 8, nd it cn lo be found tht the new mchine h better turn on nd turn off performnce predicted by the imultion. Figure 11. he prototype of BDFDS mchine. ABLE I Specifiction of the 1/8-pole BDFDS mchine Rted peed 1500 rpm Rted power 750 W Rted torque 4.70 Nm Rted phe voltge 95 V Sttor inner dimeter 75 mm Sttor outer dimeter 140 mm Stck length 75 mm Air-gp length 0.30 mm Sttor pole rc 15 Rotor pole rc Sttor pole number 1 Rotor pole number 8 urn No. of rmture winding/phe 10 urn No. of field winding 700 IAS /05/$ IEEE

8 Figure 1. eured no-lod EF wveform t rted peed (50 V/div, m/div). Figure 15. eured phe current (upper trce) nd totol torque (lower trce) wveform under rted lod (4.5 A/div,.8 Nm/div, 5 m/div). Figure 13. eured phe current (upper trce)nd phe voltge (lower trce) wveform under rted lod (4.5 A/div, 50 V/div, 5 m/div). Figure 16. eured phe current (upper trce) nd gting ignl of the upper witch (lower trce) wveform (4.5 A/div, V/div, 5 m/div). Figure 14. eured line to line voltge wveform under rted lod (50 V/div, 5 m/div). Figure 17. eured phe current (upper trce) nd gting ignl of the lower witch (lower trce) wveform (4.5 A/div, V/div, 5 m/div). IAS /05/$ IEEE

9 VII. CONCLUSION In thi pper, the deign, modeling, nd nlyi of new BDFDS motor h been preented. he output power eqution i nlyticlly derived, nd the initil clcultion of mchine dimenion nd prmeter re lo dicued. By uing finite element nlyi, the field ditribution of the BDFDS mchine t different lod nd field current re obtined, in which the mgnetic turtion nd the coupling between rmture current flux nd field current flux re conidered; moreover, the ttic chrcteritic of the propoed mchine re given. Bed on the ttic chrcteritic, the ytem mthemticl model h been etblihed. Hence, the evlution of ytem performnce i conducted by computer imultion in which the imultion model combine the mchine with three-phe hlf-bridge converter. Furthermore, 1/8-pole BDFDS mchine i deigned nd built for verifiction, drive ytem employing thi new mchine h been developed nd invetigted experimentlly. he experimentl reult under rted lod t low peed hve verified the theoreticl nlye. Figure 18. he power converter, gting drive circuit, current enor, dspace connector/led pnel nd BDFDS mchine in the exprimentl et-up. REFERENCES [1] [] [3] [4] [5] [6] [7] P. Zheng; Y. Liu; Y. Wng nd S.K. Cheng; gnetiztion nlyi of the bruhle DC motor ued for hybrid electric vehicle, IEEE rnction on gnetic, vol. 41, no. 1, 005, pp Y.Liu, Z.Q. Zhu nd Dvid Howe, Direct torque control of bruhle DC drive with reduced torque ripple, IEEE rnction on Indutry Appliction, vol. 41, no., 005, pp Cheng, K.. Chu nd C.C. Chn, Deign nd nlyi of new doubly lient permnent mgnet motor, IEEE rnction on gnetic, vol. 37, no. 4, 001, pp R. Deodhr, S. Anderon, I. Bolde nd.j.e. iller, he flux-reverl mchine: new bruhle doubly-lient permnent mgnet mchine, IEEE rnction on Indutry Appliction, vol. 33, no. 4, 1997, pp Y.F. Lio, F. Ling nd.a. Lipo, A novel permnent mgnet motor with doubly lient tructure, IEEE rnction on Indutry Appliction, vol. 31, no. 5, 1995, pp Cheng, K.. Chu, C.C. Chn nd Q. Sun, Control nd opertion of new 8/6-pole doubly lient permnent mgnet motor drive, IEEE rnction on Indutry Appliction, vol. 39, no. 5, 003, pp Cheng, K.. Chu nd C. C. Chn, Sttic chrcteritic of new doubly lient permnent mgnet motor, IEEE rnction on Energy Converion, vol. 16, no. 1, 001, pp IAS Figure 19. he power converter nd dspace connector/led pnel /05/$ IEEE