Space-Vector PWM Inverter Feeding a Permanent-Magnet Synchronous Motor

Transcription

1 Worl Acaey of Science, Engineering an echnology International Journal of Electrical, Coputer, Energetic, Electronic an Counication Engineering ol:4, No:5, 00 Space-ector PWM Inverter Feeing a Peranent-Magnet Synchronous Motor A. Maaoun, Y. M. Alsaye, an A. Shaltout International Science Inex, Electrical an Coputer Engineering ol:4, No:5, 00 waset.org/publication/496 Abstract he paper presents a space-vector pulse with oulation (SPWM) inverter feeing a peranent-agnet synchronous otor (PMSM). he SPWM inverter enables to fee the otor with a higher voltage with low haronic istortions than the conventional sinusoial PWM inverter. he control strategy of the inverter is the voltage / freuency control etho, which is base on the space-vector oulation techniue. he propose PMSM rive syste involving the fiel-oriente control schee not only ecouples the torue an flux which provies faster response but also akes the control task easy. he perforance of the propose rive is siulate. he avantages of the propose rive are confire by the siulation results. Keywors peranent-agnet synchronous otor, space-vector PWM inverter, voltage/freuency control. I. INRODUCION HE space-vector pulse with oulation (SPWM) techniue has becoe a popular pulse with oulation techniue for three-phase voltage-source inverter in the control of AC otors []-[]. Aong the various types of AC otors, the peranent-agnet synchronous otor (PMSM) is becoing a very popular choice in rive technology ue to soe of its inherent avantageous features. hese features inclue high torue to current ratio, large power to weight ratio, higher efficiency, an robustness. he PMSM rive syste involving the fiel-oriente control schee not only ecouples the torue an flux which provies faster response but also akes the control task easy [4]-[7]. he SPWM voltage-source inverters for variable voltage variable freuency (F) rives of PMSM are wiely use in both inustrial an househol applications. he SPWM inverter is use to offer 5% increase in the c-link voltage utilization an low output haronic istortions copare with the conventional sinusoial PWM inverter. he control strategy of the inverter is the voltage/freuency control etho, which is base on the space-vector oulation techniue. he SPWM inverter enables to fee the otor with a higher voltage with low haronic istortions than the conventional PWM inverter. he SPWM allows to having a higher torue at high spees, an a higher efficiency. In this paper the SPWM inverter which feeing a PMSM is siulate by using the Matlab software package. he siulation is perfore for PMSM of 0.95 kw. he perforance of the propose oel of the SPWM inverter feeing a PMSM is siulate at ifferent loaing conitions. he avantages of the propose rive are confire by the siulation results. II. SPWM ECHNIQUE he power circuit of a three-phase voltage-source inverter (SI) is shown in Fig., where a, b, an c are the output voltages applie to the star-connecte otor winings, an where c is the continuous inverter input voltage. S through S 6 are the six power transistors those shape the output, which are controlle by switching signals. When an upper transistor is switche on, the corresponing lower transistor is switche off. here are eight ifferent cobinations of switching states as follows : (000), (00), (0), (00), (0), (00), (0), an (). he first an last states o not cause a current to flow to the otor, an hence, the line-to-line voltages are zero. he other six states can prouce voltages to be applie to the otor Fig. hree-phase SI brige circuit A. Maaoun is with the Electronics Research Institute, Cairo, Egypt, Postal Coe: 6 ( corresponing author to provie fax: , e-ail : eri.sci.eg). Y. M. Alsaye is with the Electronics Research Institute, Cairo, Egypt. A. Shaltout is with the Faculty of Engineering, Cairo University, Cairo, Egypt. terinals. If the inverter operation starts by state (00) to be state, it is possible to copute the voltage space vectors for all inverter states which are shown in the coplex space vector International Scholarly an Scientific Research & Innovation 4(5) scholar.waset.org/999.5/496

2 Worl Acaey of Science, Engineering an echnology International Journal of Electrical, Coputer, Energetic, Electronic an Counication Engineering ol:4, No:5, 00 International Science Inex, Electrical an Coputer Engineering ol:4, No:5, 00 waset.org/publication/496 plane in Fig. []. he six active voltage space vectors are of eual agnitue (/) c an utually phase isplace by 60 o, as shown in Fig.. he peak funaental phase voltage that ay be prouce by the inverter for a given c link voltage occurs uner six-step operation, an is given by : six π, step c () On the other han, the axiu achievable peak funaental phase voltage for conventional sinusoial oulation as shown in Fig. is: c,sin pw () Fro euations () an (), only 78.5% of the inverter capacity is use. Fig. oltage space vectors for a three-phase SI he oulation inex M of the reference voltage space vector s is efine as the ratio of the esire peak funaental phase voltage to half the c link voltage (axiu achievable peak funaental phase voltage for conventional sinusoial PWM) as the following: M () ( c / ) he largest possible peak phase voltage that ay be achieve using the space vector oulation strategy correspons to the raius of the largest circle that can be inscribe within the hexagon of Fig.. hus, the peak funaental phase voltage that ay be achieve is: c, svpw (4) which correspons to a axiu oulation inex M ax.5. Fro euations () an (4), about 90.6% of the inverter capacity is use. his represents 5% increase in axiu voltage copare with the conventional sinusoial oulation. Consier the exaple epicte in Fig.4, in which the esire voltage is foun to lie in Sector. Although, the inverter can not prouce the esire voltage irectly. It is possible to ecopose it into two vectors, x an y, that lie on the two active inverter vectors on either sie of the reference vector[], [], [9]. herefore, in space vector notation: s x + y (5) Fig. 4 Synthesis of esire space- vector voltage using realizable voltage vectors Fig. Locus coparison of axiu peak voltage in sinusoial PWM an SPWM where the vectors, x an y, are obtaine by operating at the relevant inverter states, s an s, for suitable portions of the switching perio,. In general, when operating in s International Scholarly an Scientific Research & Innovation 4(5) scholar.waset.org/999.5/496

3 Worl Acaey of Science, Engineering an echnology International Journal of Electrical, Coputer, Energetic, Electronic an Counication Engineering ol:4, No:5, 00 International Science Inex, Electrical an Coputer Engineering ol:4, No:5, 00 waset.org/publication/496 sector, the reference vector ay be ecopose accoring to : + s s, + s, + (6) s s where an + are the ties spent at ajacent active inverter states, s, an. he reainer of the s, + switching cycle is subivie between the zero states : zero s + (7) Having copute the active an zero state ties for a particular oulation cycle, it is possible to prouce the switching signals, PWM, PWM, an PWM to be applie to the inverter. he total zero tie is ost often ivie eually between the two zero states. It is possible to satisfy the above restrictions by the use of syetrical pulses as shown in Fig. 5 [8], [9]. he cycle begins in state 0, (000), with each inverter pole being successively toggle until state 7, (), is obtaine. he pattern is the reverse in orer to coplete the oulation cycle. Fig. 5 Inverter switching signals for SM in sector III. MODEL OF PMSM he stators of the PMSM an the woun rotor synchronous otor (SM) are siilar an there is no ifference between the back EMF prouce by a peranent agnet an that back EMF prouce by an excite coil. Hence the atheatical oel of a PMSM is siilar to that of the woun rotor SM [6], [7]. he stator, euations of the PMSM in the rotor reference frae are : L i + () where P is the pole pairs, p is the /t operator, ν an ν are the, axis voltages, i an i are the, axis stator currents, L an L are the, axis inuctances, are the, axis stator flux linkages, while r an the stator resistance an rotor spee, respectively. an ω r are is the flux linkage ue to the rotor agnets linking the stator. he electroechanical torue evelope by the otor is : e P( i i ) () by substituting euations (0), an () in euation (), e P( i + ( L L ) ii ) () he relationship between the electroechanical torue an the loa torue is given as : ωr ( e l Bωr ) (4) t J θ r ωr (5) t where B is the friction coefficient, l is the loa torue an J is the oent of inertia. he inverter freuency is relate to the rotor spee as the following : ω e Pω r (6) For ynaic siulation, the euations of PMSM presente in (8)-(6) ust be expresse in state-space for as the following : pi ( ν ri Pωr Li Pωr ) (7) L pi ( ν ri + Pωr Li ) (8) L pωr ( e l Bωr ) (9) J I. SPWM INERER FEEDING A PMSM where ν ri + Pωr + p (8) ν ri Pω + p (9) L r i (0) he SPWM techniue is use to prouce the switching control signals to be applie to the three-phase inverter circuit given in Fig.. he SPWM inverter is use to offer 5% increase in the c link voltage utilization an low output haronic istortions copare with the conventional sinusoial PWM inverter. he control strategy of the SPWM inverter is the voltage/freuency control etho, which is base on the space-vector oulation techniue. For constant International Scholarly an Scientific Research & Innovation 4(5) 00 8 scholar.waset.org/999.5/496

4 Worl Acaey of Science, Engineering an echnology International Journal of Electrical, Coputer, Energetic, Electronic an Counication Engineering ol:4, No:5, 00 torue output, the air gap flux in the otor is aintaine constant by operating on a constant voltage/freuency supply. However, the analysis above assues negligible wining resistance, whereas, in practice, at low freuencies the resistive voltage rop becoes significant copare with the inuce voltage. his voltage rop causes a reuction in the air gap flux an otor torue. In orer to aintain the lowspee torue, the voltage/freuency ratio ust be increase at low freuencies. he SPWM-PMSM rive is a part of a PMSM rive syste controlle by using conventional PI controller. International Science Inex, Electrical an Coputer Engineering ol:4, No:5, 00 waset.org/publication/496. SIMULAION RESULS he SPWM inverter which feeing a three-phase PMSM is siulate using the Matlab software package. he siulation is perfore uner the following conitions : c 570, switching freuency5 khz, an three-phase PMSM (0.95 kw, N., 400,.7 A, 50 Hz, 000 rp, r.5 Ω, L7.5 H, voltage constant 97.in, J0.000 kg., an P). Figures 6 an 7 show the otor phase voltage an otor line voltage at inverter freuency f o 50 Hz an oulation inex M0.8. Figures 8 an 9 show the reference input voltage vector an the actual output voltage vector in the (α-β) planes. Also, the otor current at ifferent loaing conitions is shown in Figures 0 an. hus, the otor current has low haronic istortion. he spee response of the otor rive syste is shown in Fig.. Fig.7 Line voltage of the otor at f o 50 Hz an M0.8 voltage wavefor voltage spectru (peak value) an HD Fig. 8 Locus of reference input voltage vector in the ( α β ) plane Fig. 6 Phase voltage of the otor at f o 50 Hz an M 0.8 voltage wavefor voltage spectru (peak value) an HD Fig. 9 Locus of actual output voltage vector in the ( ) plane International Scholarly an Scientific Research & Innovation 4(5) 00 8 scholar.waset.org/999.5/496

5 Worl Acaey of Science, Engineering an echnology International Journal of Electrical, Coputer, Energetic, Electronic an Counication Engineering ol:4, No:5, 00 Fig. Spee response of the otor rive syste at loa N. International Science Inex, Electrical an Coputer Engineering ol:4, No:5, 00 waset.org/publication/496 Fig. 0 Current of the otor at f o 50 Hz, M0.8, an.5 N. current wavefor current spectru (peak value) an HD Fig. Current of the otor at f o 50 Hz, M0.8, an N. current wavefor current spectru (peak value) an HD I. CONCLUSION In this paper, a SPWM-PMSM rive has been introuce. he SPWM inverter is use to offer 5% increase in the output voltage an low output haronic istortions copare with the conventional sinusoial PWM inverter. he control strategy of the SPWM inverter is the voltage/freuency control etho which is base on the space-vector oulation techniue for constant torue operation. he avantages of the propose rive are confire by the siulation results. REFERENCES [] R. Arulozhiyal, an K. Baskaran, "Space vector pulse with oulation base spee control of inuction otor using fuzzy PI controller, " International Journal of Coputer an Electrical Engineering, vol., no., April 009, pp [] Z. Wang, J. Jin, Y. Guo, an J. Zhu, "SPWM techniues an applications in HS PMSM achines control," Journal of Electronic Science an echnology of China, vol. 6, no., June 008, pp [] A. Maaoun, A. Solian, an A. M. Kheirelen, "Space-vector PWM inverter feeing a sall inuction otor," in Proc. IEEE Int. Conf. on Mechatronics, Koaoto, Japan, May 007, pp. -4. [4] W. Kaewjina, an M. Konghirun, "ector control rive of peranent agnet synchronous otor using resolver sensor," ECI rans. Electrical Eng., Electronics, an Counications, hailan, vol. 5, no., Feb. 007, pp [5] M. Štulrajter,. Hrabovcová, an M. Franko, "Peranent agnets synchronous otor control theory,"journal of Electrical Engineering, Slovak Republic, vol. 58, no., 007, pp [6] P. Pillay, an R. Krishnan, "Moeling, siulation, an analysis of peranent-agnet otor rives, part I: the peranent-agnet synchronous otor rive," IEEE rans. Inustry Applications, vol. 5, no., March/April. 989, pp [7] P. Pillay, an R. Krishnan, "Moeling of peranent agnet otor rives," IEEE rans. Inustrial Electronics, vol. 5, no. 4, Nov. 988, pp [8] W.Zhang, an Y. Yu,"Coparison of three SPWM strategies,"journal of Electronic Science an echnology of China, vol. 5, no., Sept. 007, pp [9] A. Saaoun, A. Yousfi, an Y. Airat, "Moeling an siulation of DSP controlle SPWM three - phase SI," Journal of Applie Sciences, vol. 7, no. 7, 007, pp International Scholarly an Scientific Research & Innovation 4(5) 00 8 scholar.waset.org/999.5/496