Flux Sliding-mode Observer Design for Sensorless Control of Dual Three-phase Interior Permanent Magnet Synchronous Motor

Transcription

1 J Elctr Eng chnol Vol. 9, No. 5: , ISSN(Print) ISSN(Onlin) Flux Sliing-mo Obsrvr Dsign for Snsorlss Control of Dual hr-phas Intrior Prmannt Magnt Synchronous Motor Jian-Qing Shn*, Li Yuan, Ming-Liang Chn* an Zhn Xi* Abstract A novl quivalnt flux sliing-mo obsrvr (SMO) is propos for ual thr-phas intrior prmannt magnt synchronous motor (D-IPMSM) riv systm in this papr. h D- IPMSM has two sts of Y-connct stator thr-phas winings spatially shift by 30 lctrical grs. In this mtho, th snsorlss riv systm mploys a flux SMO with soft phas-lock loop mtho for rotor sp an position stimation, not only ar low-pass filtr an phas compnsation moul liminat, but also stimation accuracy is improv. Manwhil, to gt th rgulator paramtrs of currnt control, th innr currnt loop is raliz using a coupling an iagonal intrnal mol control algorithm. Exprimnt rsults of 2MW-lvl D-IPMSM rivs systm show that th propos mtho has goo ynamic an static prformancs. Kywors: Dual thr-phas IPMSM, Equivalnt flux linkag, Sliing-mo obsrvr; Snsorlss control. Introuction Multi-phas motor riv systm has bn wily us in many applications, spcially for high-powr applications for thir avantags compar to th stanar thr-phas ralizations, such as lowr torqu pulsations, lss c-link currnt harmonics, ruc rotor harmonic currnts, highr powr pr ampr ration for th sam machin volum, tc. [-4]. Among iffrnt multiphas motor riv solutions, on of th most wily iscuss is th VSI f ual thrphas inuction machin, having two sts of winings spatially shift by 30 lctrical grs with isolat nutral points, an thr ar many litraturs for inuction, but rlativly fw rsarch for multi-phas prmannt magnt synchronous motor (PMSM), spcially for highpowr PMSM. In many high prformanc variabl- sp AC motor rivs, fil- orint or vctor control is utiliz, an rotor-position mchanical snsor is typically rquir in this mtho. Howvr, th prsnc of mchanical snsor prsnts svral rawbacks, such as incrass th cost an siz of motors, rucs systm rliability, tc. Snsorlss control tchnology can achiv th rotor position an sp stimation through xploiting th lctrical information about th motor wining, an using a crtain control algorithm, which rprsnts th vlopmnt irction of th AC motor riv systm. So far, svral algorithms hav bn suggst in th rcnt litraturs to stimat th rotor position an th Corrsponing Author: National Ky Laboratory of Vssl Intgrat Powr Systm chnology, Naval Univrsity of Enginring, China. (li.yuan.v@qq.com) * National Ky Laboratory of Vssl Intgrat Powr Systm chnology, Naval Univrsity of Enginring, China. ccmmllcc@tom.com, xizhn7@63.com) Rciv: March 20, 203; Accpt: May 7, 204 sp of th motor. In th flux stimation mthos [5], th rotor flux is stimat by using th intgral of th iffrnc btwn th phas voltag an stator rsistanc voltag, but ths mthos ar snsitiv to machin paramtr changs, spcially th phas rsistanc. Drift an saturation problms may caus th controllr to los its synchronization ability consquntly, spcially at low sp. o gt bttr prformanc, svral improvmnt schms to flux stimation hav bn unrtakn in [6-9]. Howvr, som mthos sign for surfac PMSM ar not us for IPMSM, u to th iffrncs btwn stator inuctanc on -axis an q-axis. Sliing-mo obsrvr (SMO) is an attractiv solution compar with othr algorithms u to svral bnfits, such as high stat- stimation accuracy, xcllnt ynamic proprtis, robustnss to paramtr variations, an th ability to hanl nonlinar systm lik th IPMSM vry wll [0-3]. In this papr, a novl quivalnt flux stimation bas on SMO tchnology is propos for D- IPMSM in a stationary rfrnc fram, which also can b appli to both thr-phas surfac PMSM an IPMSM. o simplify th structur of th controllr, an quivalnt flux linkag concpt is mploy in this mtho, an th convntional switch sign function is rplac by th sigmoi function to ruc systm chattring; Morovr, a minimum four currnt rgulators ar prsnt to obtain bttr control prformanc. Simulation an xprimntal rsults will b prsnt to monstrat th fasibility of th propos control mtho. 2. Mathmatical Mo of D-IPMSM Using th vctor spac composition tchniqu [4], 64

2 Jian-Qing Shn, Li Yuan, Ming-Liang Chn an Zhn Xi th machin mol can b coupl into thr orthogonal subspacs, which ar not as ( α, β ), ( z, z2) an ( o, o 2 ). For machins with istribut winings, only ( α, β ) componnts contribut to th usful lctromchanical nrgy convrsion, whras ( z, z2) an ( o, o 2) componnts only prouc losss. An amplitu invariant coupling transformation is us as s = ransformation () is th Clark s matrix for D-IPMSM motor, ( o, o2) componnts ar omitt from th consiration sinc th machin has two isolat nutral points. A rotational transformation is appli nxt to transform th ( α, β) componnts into a synchronously rotating rfrnc fram ( q, ), which is suitabl for fil orint vctor control, i.., cos θ sin θ sin θ cosθ r = (2) h circuit quation of D-IPMSM on th q - rotating coorinat an ( z, z 2) coorinat ar givn rspctivly by whr, u uq u R+ pl ωlq i 0 u = q ω i L R pl + q q ωψ + f uz R+ plz 0 iz u = z2 0 R pl z i + z2 [ ] z z2 L Lq voltag on th q rotating fram; i iq currnt on th q rotating fram; i i currnt on th z z2 fram; stator inuctanc on th q rotating fram; L z stator lakag inuctanc; R stator rsistanc; p=/t iffrntial oprator ω angular vlocity at lctrical angl; ψ PM flux linkag f () (3) (4) ransforming (3) into stationary rfrnc fram α-β axis, (5) is riv uα R+ plα plαβ iα sin θ ωψ f u = β pl i αβ R pl + α β cosθ + whr, uα u β iα i β (5) is th stator voltag on th α - β axs, is th stator currnt on th α-β axs, an with Lα = L0 + Lcos 2 θ, Lβ = L0 Lcos 2θ L = L sin2 θ, L = ( L + L ) 2, L = ( L L ) 2. αβ 0 q q Eq. (5) contains 2θ trm, which is not asy for mathmatical procss. o liminat th 2θ trm, trm, th impanc matrix is rwrittn symmtrically lik u - R+ pl ωlq i 0 u = q ω i Lq R pl + q ωψ + m ψ = L L i i ω + ψf is fin as quivalnt flux linkag. h circuit quation on th on th α-β axis can b riv as (7) whr, m ( q)( q ) ( q) ( ) uα R+ pl ω L L iα sin θ ωψ m u = + cosθ β ω i L Lq R+ pl q β (7) whr, θ is th rotor position in lctrical raians, th PM flux linkag ψ αβ, projct onto th α-β axis can b rprsnt as ψα cosθ ψ = ψm ψ = β sin θ From th nw mol (7)-(8), th D-IPMSM can b scrib by a linar stat quation as (9). Hr, th stat variabls ar stator currnt i an PM flux linkag ψ. Assuming that th lctrical systm s tim constant is smallr nough than th mchanical on, i.., ω = 0, th vlocity ω is rgar as a constant paramtr. i A A B 2 i 0 u t ψ = 0 A ψ 0 W 2 whr, i = i i, ψ = ψ ψ α β α β. ( ) ( q ) A = R L I + ω L L J, A = ω L J, A = ω J, ( ) 2 22 (6) (8) (9) 65

3 Flux Sliing-mo Obsrvr Dsign for Snsorlss Control of Dual hr-phas Intrior Prmannt Magnt Synchronous Motor B = ( L ) I, I =, J =, 0 0 cos θ W 2 = ( L Lq)( i iq ω ) sin θ h W 2 trm in (9) is linarization rror, this trm appars only whn i or i q is changing. Howvr, unr th vlocity control this happns in a vry short tim bcaus of th high rspons of th currnt control loop. Bsis, th propos SMO has an mb low-pass filtr which can cut off th ffct of W Flux Sliing-mo Obsrvr Dsign 3. Dsign of th obsrvr o achiv th flux linkag ψ, th propos obsrvr as (0) is sign bas on th stator currnt mol (9). i A A2 i B u Ksgn( i i) t ψ = 0 A + 22 ψ 0 (0) whr, ^ nots th stimat quantitis, sgn( ) is th sign function, K is th sign paramtr, an th (0) is th convntional SMO. o ruc th chattring phnomnon, th sign function is rplac by a continuous function, i.., th sigmoi function, which is fin as 2 sig() s = + xp( as) () Hr, a is a positiv constant that can b ajust th slop of th sigmoi function. An thn, th SMO can b rwrittn as i A A2 i B u Ksig( i i) t ψ = 0 A + 22 ψ 0 Assuming that th motor paramtrs xist paramtr rrors, fin as follows (2) RL, an L q Δ R = R R, Δ L = L L, Δ L = L L. (3) q q q whr, ^ nots th stimat quantitis, Δ R, ΔL an ΔL q ar th stator rsistanc rror, th -q inuctanc rrors, rspctivly. Consiring th paramtr variations of th motor, th obsrvr (2) can b quivalnt to i A A2 i B W u Ksig( i i) t ψ = 0 A ψ 0 0 (4) whr, W is th paramtr rror input matrix, fin as follows With W i ΔB W = [ ΔA ΔA2 ] + u α = W β ψ 0 (5) ΔRL Δ Δ ΔLR LL q LL q Δ A = A A = I ω J, LL LL ΔL ΔL Δ A = A A = ω J, Δ B = B B = LL LL an K is th sign constant paramtr, satisfis K k + k 0 0 k + k K L L ( k k ) ( k k ) k ω L ( k+ k ) k2 L ( k+ k ) ω = = K2 (6) h sliing hypr-plan is fin upon th stator currnt, i.., s = [ s ] α sβ = i i= 0. So th stator currnt stimation rror ynamic function can b obtain from (9) an (4) as follows ψ α s = A s g( ) s + A 2 W K i s t + ψ α whr, ~ nots th stimat rror, such as 3.2 Lyapunov stability analysis i = i i. (7) In orr to prov th stability of th sign obsrvr, th following Lyapunov function caniat is consir. V = s = i + i (8) ( 2 2 α β). Diffrntiating (8) with rspct to tim an substituting (7) into it, thn th following quation is obtain V = iαiα+ iβiβ R = i 2 α + ωψ β i α+ W α i α ( k + k )s i g( i α) i α L L R i ωψ i + W i ( k + k )s i g( i ) i. L 2 β β β β β β β L (9) Assuming that max( W, W ) < k α β, th quation (9) can b givn as 66

4 Jian-Qing Shn, Li Yuan, Ming-Liang Chn an Zhn Xi R V < i 2 α + ωψ βiα k sig( iα ) iα L L R i ωψ i k s i g( i ) i. L 2 β β β β β L (20) Accoring to th Lyapunov stability thory, (20) must b oby to guarant that th obsrvr is stabl, i.., V < 0, th paramtr k can b chosn as R k > max{ iα + ωψ β sig( iα), L L R i β ωψ αs i g( i β)}. L L (2) Hnc, V cays to zro, thn i α an i β ar qual to zro. Aftr sliing-mo motion occurs, i.., s= s = 0, th followings quation can b obtain from (7). ψ α = ψ β ( A K ) s g( ) 2 i s (22) h flux linkag stimation rror ynamic function can b obtain from (9) an (4) as follows ψ α ψ α = A s g( ) 22 K2 i s t ψ β ψ β (23) Substituting (22) into (23), thn th following quation is obtain ψ α ψ α = k2 t ψ β ψ β (24) Hnc, if only th paramtr k 2 is a positiv gain, th (24) nsurs th rrors convrg to zro, an th convrgnc rat of rror ynamic is trmin by k 2. Howvr, whn ω is clos to zro, th comput paramtr may bcom ill-conition. o avoi this unsirabl ffct, w choos th obsrvr pols as k = γω ; hnc th obsrvr gain is calculat as 2 K k + k 0 k + k = L k + k L γ ω k + k ( ) sgn( ) ( ) sgn( ) ( ) ( ) L γ ω k + k L k+ k 3.3 Estimation of sp an position 0 (25) Convntionally, th rotor position can b stimat by using arc-angnt function β α θ = tan ( ψ ψ ) (26) Fig.. Schm of position stimation through PLL Howvr, th xistnc of nois an harmonics may influnc th accuracy of th position stimation, spcially at vry low-sp, th obvious stimation rror may occur using th arc-angnt function. o improv th position stimation for mitigation of th avrs influnc, a phaslock loop (PLL) mtho is mploy. his schm can b comparativly rprsnt as a simpl linariz closloop systm shown in Fig.. As shown in Fig., aftr th normalization of th flux linkag, th quivalnt position rror signal can b xprss as Δ θ = ( ψ sin( θ ) + ψ cos( θ )) ψ 2 2 α β α + ψβ (27) h stimation of th lctrical angular sp of th rotor is obtain using PI controllr, i.., whr, th nonngativ gains [5] ω = kiδθ (28) θ = ω + k pδθ k p an k i ar slct as 2, 2 p = i = (29) k α k α whr, a is th sign paramtr. 4. Currnt Control of D-IPMSM From th mol of th D-IPMSM, it sms that th two currnt loop control tchniqus of th thr-phas motors can b asily xtn to th six-phas rivs, as pict in Fig. 2. h phas currnts ar appli to th transformation matrix () to obtain th stator currnt 67

5 Flux Sliing-mo Obsrvr Dsign for Snsorlss Control of Dual hr-phas Intrior Prmannt Magnt Synchronous Motor Fig. 2. h convntional two currnt loop controls for D- IPMSM componnts in th stationary ( α, β) rfrnc fram. h ( q, ) currnt componnts in th synchronous rfrnc fram ar obtain by using a rotor position from th flux SMO. h outputs of th PI currnt rgulators, aftr an invrs Park transformation, ar th stator voltag rfrnc componnts in stationary rfrnc fram ( α, β) to b appli to th SVPWM moulator. h two currnt loop control stratgy pict in Fig. 2 is vry simpl, but it is not abl to compnsat for th inhrnt asymmtris of th riv. Du to th small asymmtris in th stator winings an supply voltags, th two sts of thr-phas stator currnts hav rathr iffrnt amplitus pning on th oprational conitions, an th harmonic currnts in ( z, z 2) subsystm is not liminat ffctivly. o obtain bttr controllr prformanc, a currnt control tchnology with four currnt loop rgulators in ( q, ) an ( z, z 2 ) subsystms ar aopt in this papr. Morovr, in orr to ovrcom th currnt coupling trms on ( q, ) subsystm, th coupling an iagonal intrnal mol control (DIMC) [8, 6] structur for currnt control in th riv. h comman voltag ar now givn by R u * * = β( L + )( i i) ωli q q s R u * ( )( * ) q = β Lq + iq iq + ω( Li + ψ f ) s R u * * z = β( Lz + )( iz iz) s R u * * z2 = β( Lz + )( iz2 iz2). s (30) whr, β is th sir clos-up banwith as trmin by th spcifi ris tim of th currnt controllr. h DIMC involvs only a singl paramtr, so tuning of th controllr to giv spcifi prformanc is asir. h sp controllr outputs th q-axis currnt * rfrnc i q, an th z -axis an z 2 -axis currnt rfrncs i * z an i * z2 ar st to zro, so th ovrall block iagram of th D-IPMSM control schm can b shown in Fig. 3. o obtain bttr rsults an implmnt simply, it is suggst in this papr th ual thr-phas SVPWM tchniqu as shown in Fig. 4 is us for moulation in this papr, th tail iscussion can b sn in [7]. It is has many avantagous, such as xisting algorithms an tst thr-phas moulation mthos can b ffctivly utiliz, Fig.3 Block iagram of th snsorlss flux SMO control riv schm Fig. 4. h ual thr-phas spac vctor classification PWM tchniqu which can sav tim an troubl. It also maks th mtho computationally fficint sinc yars of xtnsiv stuy an wi usag hav ma spac vctor moulation a vry simpl task. 5. Simulation an Exprimnt Rsults o chck th fasibility of th propos rotor position an sp stimation schms, th simulation an xprimntal stuis ar carri out with a rfrnc to a 2 MW D-IPMSM rivs systm. h block iagram of th snsorlss flux obsrvr control rivs is prsnt in Fig. 5, an th machin paramtrs ar givn in abl. h sam controllr paramtrs ar us both in simulation an xprimntal rsults. A stator currnt controllr banwith β of 30ra/s, an th PLL systm banwith a of 3ra/s abl. th paramtrs of D-IPMSM rat powr 280kW rat voltag 690V rat sp 7r/min rat frquncy 8.5Hz rotor inrtia 6000 kg.m 2 numbr of pol pairs 30 stator rsistanc pr phas (R) Ω -axis inuctanc (L ) 4 mh q-axis inuctanc (L q ) 5 mh Prmannt magnt flux( ψ ) f Wb 68

6 Jian-Qing Shn, Li Yuan, Ming-Liang Chn an Zhn Xi ar chosn. h paramtrs of flux obsrvr ar chosn as followings: k + k = 300, L γ = Simulation rsults Figs. 5 an 6 show th two sts of simulation wavforms whn th rfrnc sp is a stp signal. In th simulation, th rfrnc sp is chang from 5 to 7 r/min, an th loa torqu is N.m. Fig. 5 isplays th simulation wavform obtain by th convntional SMO mtho using a sign function. Fig. 6 shows th simulation wavform obtain by th mtho propos in this papr. It can b sn from Figs. 5 that th sign function can caus to chattring phnomnon, th low pass filtr an phas compnsation part must b us, an thrfor, th rotor position stimation accuracy is not high. Howvr, it can b sn from Fig. 6 that th chattring phnomnon of th stimat rotor position an sp is ruc, an th accuracy of rotor position stimation is improv to som xtnt. Fig. 7 shows th stimation prformanc of th propos mtho whn th paramtrs of D-IPMSM vary. In th simulation, th rfrnc sp is 7 r/min, an th loa torqu is N m. It can b sn from Fig. 7 that, whn th rsistanc or th inuctanc of th motor changs, th stimat sp can still convrg to th actual valu, which vrifis th robustnss of th propos approach. 5.2 Exprimnt rsults Fig. 5. h simulation wavforms obtain by th convntional SMO mtho using sign function: (a) Actual an stimat sps; (b) Actual rotor position, stimat rotor position, an stimat rror; (c) Estimat flux ψ αβ,. h ffctivnss of th propos snsorlss control schm for 2 MW-lvl D-IPMSM riv is tst using th xprimnt stup shown in Fig. 8. In th xprimnt stup, a high-powr back-to-back convrtr systm is us to f th riv systm, an th controllr an machin paramtrs ar sam with th simulation, an th sampling prio of th control systm is st as 50 μs, th a-tim is st as 0 μs, th switch frquncy is st as khz. h ovrall systm control algorithm is vlop in Matlab/ Simulink, follow by implmntation on an OPAL R- Lab (Ral-tim Digital Simulator) controllr boar. h motor paramtrs ar givn in abl. Figs. 9 an 0 show th control prformanc whn th D-IPMSM is running with th rfrnc sp stps up from 2 to 0 r/min. Fig. 9 shows th wavforms whn th Fig. 6 h Simulation wavforms obtain by th convntional mtho using sign function: (a) Actual an stimat sps; (b) Actual rotor position, stimat rotor position, an stimat rror; (c) Estimat flux ψ αβ,. Fig. 7. Simulation wavforms whn th paramtrs of D- IPMSM ar chang: (a) Wavforms whn th rsistanc is chang; (b) Wavforms whn th inuctanc is chang. 69

7 Flux Sliing-mo Obsrvr Dsign for Snsorlss Control of Dual hr-phas Intrior Prmannt Magnt Synchronous Motor Fig. 8. h ovrall xprimnt stup Fig. 0. Oprating wavforms obtain by th propos mtho using a sigmoi function: (a) From top to bottom ar th stimat rotor sp, rotor rror an stimat flux-linkag, rspctivly; (b) From top to bottom ar th stimat rotor position, an stimat rror, rspctivly. Fig. 9. Oprating wavforms obtain by th convntional control mtho using a sign function: (a) From top to bottom ar th stimat rotor sp, rotor rror an stimat flux-linkag, rspctivly; (b) From top to bottom ar th stimat rotor position, an stimat rror, rspctivly. convntional mtho bas on th sign function an lowpass filtr is aopt. As can b sn from Fig. 9, u to th us of th sign function, th chattring of th stimat rotor position an sp obtain by th traitional mtho is significant. Whn th propos flux SMO is mploy, Fig. 0 prsnts a goo ynamic prformanc of stimat sp, th stimat sp follows th rfrnc sp vry wll, an th sp stimat rror is vry small. Espcially, thr is a small rippl ( ± 0.r/min) whn D-IPMSM riv runs in a stabl sp rang. An th chattring is ruc whn th sign function is rplac by th sigmoi function, an th wavforms of th stimat rotor position an sp obtain by th propos flux SMO ar smooth. 6. Conclusion In this papr, a novl flux linkag sliing-mo obsrvr for D-IPMSM snsorlss rivs has bn propos. o 620

8 Jian-Qing Shn, Li Yuan, Ming-Liang Chn an Zhn Xi simply th machin mol, an quivalnt flux linkag concpt is mploy. h sign function is rplac by th sigmoi function to ruc th chattring, an th convntional SMO is improv. From th sign procss w can s that th prsnt obsrvr has a simpl structur with lss control paramtrs. Manwhil, th tails of th obsrvr paramtrs an th rotor position an sp stimators ar givn. h fasibility of th propos schm is vrifi an confirm through simulation an xtnsiv xprimnts. Acknowlgmnts h work scrib in this papr was fully support by a grant from th Major Stat Basic Rsarch Dvlopmnt Program of China (No.203CB03560), an th Projct support by th Program for Nw Cntury Excllnt alnts in Univrsity of Ministry of Eucation of China (No.NCE--087). Rfrncs [] E. Lvi, Multiphas lctric machins for variablsp applications, IEEE rans. In. Elctron., vol. 55, pp , May [2] E. Lvi, R. Bojoi, F. Profumo, H. A. oliyat, an S. Williamson, Multi- phas inuction motor rivs - a tchnology status rviw, IE Elctr. Powr Appl., vol., pp , July [3] R. Bojoi, M. lazzari, F. Profumo, an A. nconi, Digital fil-orint control for ual thr-phas inuction motor rivs, IEEE rans. In. Appl. vol. 39, pp , May/Jun [4] G. K. Singh, K. Nam, an S. K. Lim, A simpl inirct fil-orint control schm for multiphas inuction machin, IEEE rans. In. Elctr. vol. 52, pp , August [5] R. Wu, an G. Slmon, A prmannt magnt motor riv without a shaft snsor, IEEE rans. In. Appl., vol. 27, pp , May. 99. [6] S. Shinnaka. Nw snsorlss vctor control using minimum-orr flux stat obsrvr in a stationary rfrnc fram for prmannt-magnt synchronous motors, IEEE rans. In. Elctr., vol. 53, pp , April [7] Su Jianyong, Li icai, Yang Guiji. PMSM snsorlss control bas on four-orr hybri sliing mo obsrvr [J]. Procings of th CSEE, vol. 24, pp , [8] Chan F, Wang W, Borsj P, tc. Snsorlss prmannt magnt synchronous motor rivs using a ruc-orr rotor flux obsrvr [J]. IE Elctric Powr Applications, vol. 2, pp , [9] Z. Xu, M. F. Rahman, An aaptiv sliing stator flux obsrvr for a irct-torqu-controll IPM synchronous motor riv IEEE rans. In. Elctr., vol. 54, pp , Oct [0] L. Yuan, F. Xiao. J Q Shn,tc, Snsorlss control of high- powr intrior prmannt magnt synchronous motor rivs at vry low sp, IE Elctrical powr & Applications, vol. 7, pp , April [] Yuan Li, Shn Jian-qing, Xiao Fi, tc. Nonsingular trminal sliing-mo obsrvr sign for intrior prmannt magnt synchronous motor riv at vry low-sp [J]. Acta Physiac Sinica, vol. 7, pp , 203. [2] Z. Chn, M. omita, S. Doki, an S. Okuma, h pol assignmnt of aaptiv sliing obsrvrs for BLM s snsorlss control, in Nat. Conv. Rc. IEEJ, vol. 4, pp , Mar [3] G. Foo,an M. F. Rahman, snsorlss sliing-mo MPA control of an IPMSM synchronous motor riv using a sliing-mo obsrvr an HF signal injction, IEEE rans. In. Elctron., vol. 57, pp , April [4] Y. Zhao, an. A. Lipo, Spac vctor PWM control of ual thr-phas inuction machin using vctor spac composition, IEEE rans. In. Appl., vol. 3, pp , Sp./Oct [5] L. Harnfors an H. P. N, A gnral algorithm for sp an position stimation of AC motors, IEEE rans. In. Elctr., vol. 47, pp , Fbruary [6] L. Harnfors, an H. P. N, Mol-bas currnt control of AC machins using th intrnal mol control mtho, IEEE rans. In. Appl., vol. 34, pp. 33-4, Jar./ Fb [7] R. Bojoi, A. nconi, F. Profumo, G. Griva, an D. Martinllo, Complt analysis an comparativ stuy of igital moulation tchniqus for ual thr-phas AC motor rivs, in Proc. IEEE PESC 02, pp , Jian-Qing Shn rciv th Ph.D. gr from Naval Univrsity of Enginring (NUE) in 2007, an is prsntly a rsarch fllow at NUE. His aras of rsarch ar control mtho sign of nw typ of lctrical machin, powr lctronics an its applications in inustry an powr systm, an powr systm intgration tchniqu applications Li Yuan rciv his B.S gr from Naval Univrsity of Enginring (NUE) in 200, an is currntly working towar th Ph.D. gr at NUE. His currnt intrsts inclu powr lctronics an th control mtho sign of nw typ of lctrical machin. 62

9 Flux Sliing-mo Obsrvr Dsign for Snsorlss Control of Dual hr-phas Intrior Prmannt Magnt Synchronous Motor powr systm. Ming-Liang Chn rciv th Ph.D. gr from Naval Univrsity of Enginring (NUE) in 2008, an is prsntly an associat rsarch fllow at NUE. His aras of rsarch ar control mtho sign of nw typ of lctrical machin, powr lctronics an its applications in inustry an Zhn Xi rciv th B.S an Ph.D. grs from Naval Univrsity of Enginring (NUE) in 2009 an 203. His currnt intrsts inclu highpowr powr lctronics tchniqu applications. 622