A Novel Axial Flux Stator and Rotor Dual Permanent Magnet Machine

Transcription

1 4 CE TRAACTIO O ELECTRICAL MACHIE AD YTEM, VOL., O., JUE 7 A ovel Axial Flux tato and Roto Dual Peanent Magnet Machine Y. C. Wang, W.. Fu, and X. J. Li Abtact A novel tuctue of axial flux tato and oto dual PM Venie achine i peented a an effective option fo high toque-denity diect-diven application. The key i to locate PM on both ide of oto and tato. With dual PM, thi popoed achine with a novel tuctue geneate an ipoved toque pe aatue cuent at low peed. It i vey uitable fo diect dive application with liited pace uch a the in-wheel electic vehicle (EV) oto. The theoy of the tuctue with PM on both ide i analyzed theoetically. The tuctue and opeation pinciple of achine ae intoduced and the teady and teady pefoance of achine i analyzed and veified with tie-tepping finite eleent ethod (T-FEM). Index Te Diect-dive, finite eleent ethod, flux odulation, high toque denity, peanent agnet D I.. ITRODUCTIO UE to the daatical ipoveent of the pefoence of peanent agnet (PM) ateial, PM achine have been applied in oe and oe application field, anging fo indutial field uch a wind powe geneato, electical vehicle to doetic appliance [-3]. PM achine own any obviou eit including high efficiency and high powe denity, ove any othe electic-excited achine. PM achine can be claified a gea box baed type and diectdive type. Fo the foe one, a eduction gea i alway eential fo taditional dive yte becaue of the iatching between the dive yte and the load. Howeve, the echanical eduction gea bing oe additional poble uch a echanical vibation, noie and aintenance cot. To get id of the eduction gea, diect-dive PM achine i one of the eeach diection fo oden dive yte. Vaiou topologie of the PM achine have been popoed in the pat decade yea to be degined a diectdive achine [4-7]. PM venie achine a one pecial cae of flux odulation achine ae exteely uitable fo the low-peed high-toque-denity diect-dive yte. Thi wok wa uppoted in pat by the Reeach Gant Council, the Hong Kong pecial Adinitative Region, China, unde poject PolyU 53/4E. Yunchong Wang i with The Hong Kong Polytechnic Univeity, Hung Ho, Kowloon, Hong Kong, China (e-ail: wangycee@gail.co). W.. Fu i with The Hong Kong Polytechnic Univeity, Hung Ho, Kowloon, Hong Kong, China (eewnfu@polyu.edu.hk). Xingjian Li i with Xi'an Jiaotong Livepool Univeity, uzhou, Jiangu, China ( @qq.co). Venie oto tuctue wa popoed fitly by Lee [8] in 963. ince the PM achine wa not popula, the fit Venie oto i a eluctance-type inducto ynchonou oto. The PM Venie achine (PMVM) with high pefoance PM ateial ha the featue of high toque at low peed [9-]. PMVM i alo one type of agnetic geaed achine achine o flux odulating achine due to the inheent agnetic gea effect. The Venie tuctue of PMVM aplifie eveal pecific pace haonic of agnetic field with odulation of uneven ai-gap peeance in the ai-gap. With the inteaction between thee pecific haonic and agnetic field excited with oto PM, the PMVM poduce lage toque at low peed. Fo the conventional PM ynchonou achine (PMM), the tato winding and oto PM have ae pole nube. Howeve, in the PMVM, the pole nube of tato winding and the oto PM ae diffeent. The gea atio of the PMVM i dependent on the election of the pole nube of the oto PM (Z ) and pole nube of the tato winding (p). The gea adio i alway uch geate than one which ean p i alway deigned uch alle than Z. Axial-flux peanent-agnet achine (AFPMM) have been tudied fo eveal decade [3-5]. The extee axial copactne of the AFPMM i it ajo advantage, which ake it vey uitable fo the pace liited application, uch a ued a in-wheel oto fo the electical vehicle (EV) and wind powe geneato. Baed on the tuctue, AFPMM can be divided into ingle-tato, ingle-oto, double-tato, ingle-oto, ingle-tato, double-oto and ulti-tack tuctue. Fo the ingle-tato, double-oto achine, the winding can be wounded a ing winding which ae alo known a back to back o coe-wound winding. Copaed with taditional tooth-wound winding, the ing winding have excellent pefoance ince the end connection i hote and the winding utilization i highe. Fig. (a) how the ingletato, double-oto topology with coe-wound winding and PM. The indicate that oppoing agnet ae of ae polaity. Fig. (b) how the ingle-tato, double-oto topology with coe-wound winding and PM. The indicate that oppoing agnet ae of oppoite polaity. In thi pape, a novel axial flux dual peanent agnet (AFDPM) achine i popoed. The AFDPM achine adapt ingle-tato, double-oto tuctue and coe-wound winding a hown in Fig.. The baic opeating theoy of the AFMPMM i that it eploy flux odulating effect to integate the agnetic gea and peanent agnet ynchonou achine (PMM) copactly. With 3d finite

2 WAG et al: A OVEL AXIAL FLUX TATOR AD ROTOR DUAL PERMAET MAGET MACHIE 4 eleent ethod (FEM), the theoy i veified and the pefoance of the novel tuctue i analyzed. A conventional axial flux venie PM achine (AFVPM) with iila ated peed and volue i tudied to copae with the AFDPM achine in te of the toque denity. With PM on both ide of the ai-gap, the toque denity of the AFDPM achine i ipoved daatically when copaed with conventional diect-dive achine. (a) (b) Fig.. The tuctue of ingle tato-double oto. (a) coe-wounding with PM. (b) coe-wounding with PM. tato Winding Roto Roto PM tato PM Fig.. The tuctue of the AFMPMM. II. OPERATIG PRICIPLE OF DUAL PM FLUX MODULATIO MACHIE tato q q conducto Roto Fig. 3. Potion of axial flux tato and oto dual PM achine. To illuinate the theoy of the AFDPM achine, a potion of the co ection of the axial flux tato and oto dual PM achine i hown in Fig. 3. To iplify the 3d odel to a d diaga, the ac i hown a taight line. The fundaental PM coponent of the agnetic otive foce (MMF) developed by the oto PM i expeed in Eq. () and the ai-gap peeance i expeed in Eq. () below. F q q F co ( q q ) PM, 4 h B q q q co ( ) P P co( ) P Z q () whee, i the pole pai nube of the oto PM, Z i the tato lot nube, q i the oto poition and q i the angula poition in the ai gap. h i the thickne of the oto PM. Fo Eq. () and Eq. (), the ai-gap flux denity developed by oto PM i given by Eq. (3). q, q q, q q B F P PM 4 h B co q q q P P co( Z ) P co q q 4 h P B co( Z ) q q (3) P co( Z ) q q The flux linkage within one tato pole ange due to the oto PM i given a: / p, q B q q dq 4 h P B in q q P Z in ( Z ) q q P in ( Z ) q q Z whee, P i the pole pai nube of the tato winding, and ae the oute adiu and inne adiu of the oto PM, epectively. When the pole-pai nube of oto PM equal to the pole-pai nube of the tato winding, naely = p, the flux denity due to the flux odulation effect with ± i negligible and thee i no gea effect. To eploy the flux odulation effect, the pole pai nube hould atify the elationhip -Z = ±p. Eq. (4) can be ewitten a: 4 h P q B q in p P in q (5) whee, i the aplitude of winding flux linkage developed by the oto PM: 4 h P P B (6) p The agnetic field of the oto PM i odulated by the tato lot. The oto PM and the tato lot conit of the fit p () (4)

3 4 CE TRAACTIO O ELECTRICAL MACHIE AD YTEM, VOL., O., JUE 7 et of flux odulation goup. The oto lot and the tato PM ineted into the tato lot conit of the econd odulation goup. In the ae way, the agnetic field excited by the tato PM i odulated by the oto ion egent. The pole pai nube of the tato PM i Z and the oto pole nube i, the MMF developed by the tato PM i expeed in Eq. (7) and the elevant ai-gap peeance i expeed in Eq. (8). F q, q F co Z q PM 4 h B cozq q P P co ( q q ) (7) P (8) The additional in (8) i the angle diffeence between the oto PM and the oto lot, and h i the thickne of the tato PM. The ai-gap flux denity developed by tato PM i expeed a: B q q F q q P q, PM, P coz q 4 h P B co ( Z ) q q (9) P co ( Z ) q q The flux linkage within one pole ange of the tato winding due to the tato PM i given a: 4 h P q B q in p in q () The flux linkage of the tato winding i the upepoition of thee two field and can be expeed a: q q q P in q () whee, PM i the flux linkage excited by the oto PM and PM i the flux linkage excited by the tato PM. III. PERFORMACE AALYI WITH FEM TABLE I PARAMETER OF the popoed achine Paaete AFDPM achine Rated Powe(kW) 3 Rated peed (p) 6 ube of winding pole 4 tato Oute diaete () tato Inne diaete () 8 tato PM thickne () 5 ube of tato lot 8 ube of tato all lot 5 Roto oute diaete () 5 ube of oto pole Roto PM thickne () 4.5 Reanence of agnet (T).4 Rated peed (p) 6 Ai gap length ().5 tack length () 45 TABLE I how the pecification of the odel. With 3d- FEM, the achine pefoance i analyzed. The flux denity ditibution of the AFDPM achine i hown in Fig. 4. To illuinate the flux denity ditibution clealy, the top pat of the oto i concealed. Fig. 5 how the flux linkage of one phae of tato winding. To veify the Venie theoy conducted in Pat II, the flux linkage developed by the oto PM, tato PM and the upepoition flux linkage ae hown epectively. The olid line i the upepoition flux linkage, the boken line i the flux linkage developed by the tato PM and the dotted line i the flux linkage developed by the oto. A een fo Fig. 5, the flux linkage developed by the tato PM and oto PM have the ae phae and the upepoition flux linkage i thei linea uation. Fig. 4 Flux denity ditibution of the AFDPM achine A. Aigap Flux Denity Ditibution Fig. 5 and fig.6 how the coputed flux ditibution in the aigap. The axial flux denity due to the tato PM, a well a thei pace haonic pecta, ae hown epectively in fig. 5(a) and fig. 5(b). The axial flux denity due to the oute winding in the aigap, a well a thei pace haonic pecta, ae hown in Fig. 6(a) and 6(b), epectively. It i eay to ee that the pole-pai haonic i alle than the 8 pole-pai haonic but lage than othe haonic becaue of the venie effect. The pole-pai haonic i the functional haonic to couple with the tato winding. The axial flux denity due to the inne tato PM, a well a thei pace haonic pecta, ae hown epectively in Fig. 6(a) and fig.6(b) how the axial flux denity due to the oto tato PM and it pace haonic pecta. (a)

4 Back EMF [V] Flux Linkage [Wb] WAG et al: A OVEL AXIAL FLUX TATOR AD ROTOR DUAL PERMAET MAGET MACHIE 43 nube, the ajo peipheal dienion of the AFVPM achine ae the ae a the AFDPM achine, except the PM ae only ounted on the oto without lot. The no load back EMF of the novel tato and oto dual PM tuctue i uch lage the conventional Venie tuctue in the ae ize a hown in Fig. 9. It indicate the novel tuctue ha highe powe denity and toque denity than the conventional AFVPM achine with the ae electic loading and agnetic loading. The no load back EMF i inceaed fo 8V of the AFVPM achine to V of the AFDPM achine. (b) Fig. 5 Flux denity ditibution of the AFDPM achine. Due to tato and oto PM Due to tato PM Due to oto PM Roto poition in electical angle [degee] Fig. 7 Flux linkage of the tato winding with diffeent oto poition (a) Fig. 8. tuctue of a conventional axial flux venie PM achine. (b) Fig. 6 Flux denity ditibution of the AFDPM achine B. Benefit of the Dual PM tuctue The no-load back EMF i iulated at 6 p and hown in Fig. 7. In accodance with the flux linkage wavefo, the olid line i the total no-load back EMF of the AFDPM achine. The boken line i the back EMF excited by the tato PM and the oto PM ae conideed a vacuu. The back EMF excited by tato PM i a little lage than the back EMF excited by the oto PM. It i becaue that the tato PM i thicke than the oto PM a hown in TABLE I. The dotted line i the back EMF excited by the oto PM and the tato PM ae conideed a vacuu. The additional boken dot line i the back EMF of a conventional AFVPM achine. The tuctue of the conventional AFVPM achine i hown in Fig. 8. With ae oto pole pai nube, and tato lot AFDPMM Due to tato PM Due to oto PM AFVPMM Roto poition in electical angle [degee] Fig. 9. o-load back EMF of the tato winding with diffeent oto poition.

5 Toque [] Toque [] 44 CE TRAACTIO O ELECTRICAL MACHIE AD YTEM, VOL., O., JUE 7 Fig. how the axiu toque with diffeent aatue cuent. The toque-cuent chaacteitic i not a taight line fo both AFDPM achine and AFVPM achine. The eaon i that the aatue eaction caue the agnetic atuation when the cuent denity i high. ae a the no-load back EMF, the toque of the AFDPM achine i alo highe than the AFVPM achine with the ae winding cuent. 6 AFDPMM AFVPMM Fig.. Coe lo with full condition Cuent denity [A/ ] Fig.. Maxiu toque with diffeent aatue cuent denity. C. Tanient Toque and Efficiency 5 4 Tanient toque with 6p and 7A cuent IV. COCLUIO In thi pape, a novel tuctue of axial flux tato and oto dual PM achine i popoed. The novel achine ha the eit of high powe denity and toque denity at low peed. It i uitable fo diect dive application with liited pace uch a in-wheel electical populion yte. The flux odulation effect i foulated and woking pinciple i explained. 3d-FEM i eployed to pove the accuacy of the odel and the tanient and tatic pefoance of achine i analyzed. Copaed with conventional axial flux PM achine, the toque denity i ipoved by aound % a hown in the iulation eult Fig.. Tanient toque at 6 p. Tie [] Fig. how the teady toque wavefo of AFDPM achine with 7 A cuent denity and 6 p otation peed. The toque ipple i 5 (peak to peak). Due to the dual PM tuctue, it i lage than the toque ipple of convention AFPM achine. Thi i a ajo dawback of the AFDPM achine. Uing the ultilaye tuctue, the toque ipple of the AFDPM achine can be uppeed. Fig. how the coe lo of the AFDPM achine with full load condition. In full load condition, the coppe lo of the AFDPM achine i 7W and the coe lo 39W. Conideing the tay lo i %, the efficiency of the AFDPM achine i 9.4% in the full load condition. REFERECE [] K. T. Chau, C. C. Chan, and C. Liu, Oveview of peanent-agnet buhle dive fo electic and hybid electic vehicle, IEEE Tan. Indu. Electon., vol. 55, no. 6, pp , Jun. 8. [] Z. Q. Zhu and D. Evan, Oveview of ecent advance in innovative electical achine With paticula efeence to agnetically geaed witched flux achine, in Poc. Intenational Confeence on Electical Machine and yte, Hangzhou, China, Oct. 4, pp.. [3] T.M. Jahn, The expanding ole of PM achine in diect-dive application, in Poc. Intenational Confeence on Electical Machine and yte, Beijing, China,, On page(): - 6 [4] M. Cheng, K. T. Chau and C. C. Chan, Deign and analyi of a new doubly alient peanent agnet oto, IEEE Tan. Magn., vol. 37, no. 4, pp.3-3 [5] M. F. Rahan, M. E. Haque, L. Tang and L. Zhong, Poble aociated with the diect toque contol of an inteio peanent-agnet ynchonou oto dive and thei eedie, IEEE Tan. Ind. Electon., vol. 5, no. 4, pp [6] A. M. El-Refaie and T. M. Jahn, Copaion of ynchonou PM achine type fo wide contant-powe peed opeation: Convete pefoance, IET Elect. Powe Appl., pp. 7, 7. [7] Y. Wang,. L. Ho, W.. Fu and J. X. hen, A ovel Buhle Doubly Fed Geneato fo Wind Powe Geneation, IEEE Tan. Magn., vol. 48, no., pp , ovebe. [8] C. H. Lee, Venie oto and it deign, IEEE Tan. Powe App. yt., vol. PA-8, no. 66, pp , Jun [9] A. Ihizaki, T. Tanaka, K. Takaaki, and. ihikata, Theoy and optiu deign of PM Venie oto, in Poc. intenational confeence on electical achine and dive, Picataway, ew Jeey, 995, pp. 8.

6 WAG et al: A OVEL AXIAL FLUX TATOR AD ROTOR DUAL PERMAET MAGET MACHIE 45 [] B. Ki and T. Lipo, Opeation and deign pinciple of a PM venie oto, IEEE Tan. Ind. Appl., vol. 5, no. 6, pp , ov./dec. 4 []. iu,. L. Ho, W.. Fu, A novel tato and oto dual peanent agnet Venie oto with pace vecto pule width odulation, IEEE Tan. Magn., vo.l 5. no., pp.85-88, Feb 4. [] T.. Kwon,. K. ul, L. Albeti,. Bianchi, Deign and contol of an axial flux achine fo a wide flux-weakening opeation egion, in Conf. IEEE Induty Application Annual Meeting 7, ew Olean, Louiiana, 7, pp [3] H. Tiegna, A. Bellaa, Y. Aaa and G. Baakat, Analytical odelling of the open-cicuit agnetic field in axial flux peanent agnet achine with ei-cloed lot," IEEE Tan. Magn., vol. 48, no. 3, pp. -6 ov. [4]. Huang, J. Luo, F. Leonadi and T. A. Lipo, A copaion of powe denity fo axial flux achine baed on geneal pupoe izing equation, IEEE Tan. Enegy Conve., vol. 4, no., pp [5] F. G. Capponi, G. De Donato, and F. Caicchi, Recent advance in axialflux peanent-agnet achine technology, IEEE Tan. Ind. Appl., vol. 48, no. 6, pp. 9 5, ov./dec.. Xingjian Li wa bon in Chaoyang, Liaoning, China, in 995. He i cuently tudying at Xi'an Jiaotong Livepool Univeity fo hi bachelo degee in electical engineeing. Yunchong Wang eceived hi B.c and M.c degee, fo the chool of Electical Engineeing, Zhejiang Univeity, Zhejiang, China, in and 3, epectively. He i cuently woking towad the Ph.D. degee in the depatent of Electical Engineeing fo The Hong Kong Polytechnic Univeity. Hi eeach inteet include electical oto deign and contol, electical vehicle and enewable enegy conveion yte. W.. Fu eceived hi BEng in Electical Engineeing, Hefei Univeity of Technology, Hefei, China in 98 and MEng in Electical Engineeing, hanghai Univeity of Technology, hanghai, China in 989. He obtained hi PhD in electical engineeing fo The Hong Kong Polytechnic Univeity in 999. He i now a Pofeo in The Hong Kong Polytechnic Univeity. Befoe joining the univeity in Octobe 7, he wa one of the key develope at Anoft Copoation in Pittbugh, UA. He ha about even yea of woking expeience at Anoft, focuing on the developent of the coecial oftwae Maxwell. He ha publihed 84 pape in efeeed jounal. Hi cuent eeach inteet ainly focu on nueical ethod of electoagnetic field coputation, optial deign of electic device baed on nueical odel, applied electoagnetic and novel electic achine.