英文文献.pdf

Abstract Firstly, the basic principle of space vector pulse width modulation (SVPWM) technology is introduced simply in this paper. Then, simulation model of permanent magnet synchronous traction motor control system is established based on MATLAB/Simulink. The starting and braking characteristics simulation results show that the model is effective, as well as the PI adjuster parameters is appropriate. The simulation model and method provides a base for both software and hardware design of an actual control system of permanent magnet synchronous traction motor. I. INTRODUCTION At present, the sinusoidal pulse width modulation (SPWM) method generating a variable frequency and variable voltage three-phase symmetrical sinusoidal voltage source has been widely used in AC drive systems. The SPWM is simple in principle and is easy to come true, but utilization of the DC supply voltage is not high. So, the current control mode, particularly hysteresis current control, is developed. Characterized by simple mathematical model, fast response speed as well as good robust, this control method is widely used. However, the circuit switching losses and circuit efficiency depending on the width of hysteresis and carrier frequency, the application is limited in some cases. SVPWM technology is a new pulse width modulation algorithm with high efficiency. Compared with the traditional SPWM, this algorithm has a high utilization of bus voltage, wide linear modulation range, good real-time control, and is facilitate to realize in digital system. Thus, SVPWM technology is taken in this permanent magnet synchronous traction motor control system. II. BASIC PRINCIPLE Within a variety of PWM technologies, SVPWM has been more applied in the all-digital AC drive system due to its advantages of easy digital and high modulation ration. SVPWM expresses the eight on/off states of the three-phase voltage-source inverter, and that is, respectively, 000, 100, 110, 010, 011, 001, 101, 111, where 1 means turning on the upper bridge arm, while 0 for the latter bridge. Therefore the eight switching states correspond to eight basic voltage vectors denoted by U0-U7. When only vector U0or U7, the motor stator flux vector is fixed, thus they are also called zero vectors. The inverter and motor are considered as a whole in SVPWM, and in which eight basic voltage vectors are used to synthesis the desired voltage vector, then the inverter switching states of the power devices are established upon them. The key of the SVPWM algorithm is to determine the dwell time of the two adjacent effective vectors during one PWM cycle. Fig.1 shows the relationship of the eight basis space voltage vectors, different acting time and the desired equivalent space voltage vector needed by the motor. )100(0U)110(60U)010(120U)011(180U)001(240U)101(300UU outT1T 2Fig. 1. Basic voltage vectors and the desired voltage vector Fig.2 shows the block diagram of rotor field-oriented vector control system. The deviation between the given speed n* and the feedback speed n is regulated through the speed PI regulator. The output is q-axis reference current component iq* to control the torque. The deviations between iq*, id* and current feedback quantity iq, idgo through the current PI regulator, and respectively output phase voltage Vq* and Vd* on the d-q revolving coordinate system. Vq* and Vd* are transformed into the stator phase voltage vector component V*and V* under - coordinate system through inverse Park transform. If the stator phase voltage vector Vq*, Vd* and its sector number is known, we can use the voltage space vector PWM technique to produce PWM signal controlling the inverter, so as to achieve closed-loop control of the PMSM. n*nPI PIPIiq*id*V q*V d* Park1_SVPWMInverterV DCPMSMClarkParkiAiBiiU*U*iqidSensorPositionSpeednCalculatio+ +_Fig. 2. Principle diagram of vector control system Study on Starting and Braking Characteristics of Permanent Magnet Synchronous Traction Motor Ying Pei1, Xiuhe Wang1, Yufang Wang2, Tongshan Diao11Department of Electrical Engineering, Shandong University, Jinan, 250061, China 2Shandong Yingcai University, Jinan, 250104, China E-mail: III. THE ESTABLISHMENT OF SIMULATION MODEL MATLAB/Simulink-based simulation model is mainly made of coordinate transform module, SVPWM production module and PMSM module. A. Coordinate Transform Module There are two kinds of coordinate system in this control system. One is a static - coordinate system, which is fixed on the stator; the other is a revolving d-q coordinate system, which is fixed on the rotor. Equation (1) gives the transform from - to d-q coordinate system. While (2) gives the transform from d-q to - coordinate system. d q cos sinsin cosii = (1) d qcos sinsin cosii = (2) The coordinate transform module based on MATLAB/Simulink is shown in Fig.3. (a) From - to d-q coordinate system transform (b) From d-q to - coordinate system transform Fig. 3. Simulation model of coordinate transform module B. The Module of SVPWM Production The module of SVPWM production is composed of the judgment of the sector, the calculation of the basic voltage vector acting time, and the calculation of switching time. 1) The judgment of the sector Firstly, we can calculate U1, U2and U3according to (3). 1 233232UUUUUUUU = =(3) If U10, a=1, otherwise, a=0; If U20, b=1, otherwise, b=0; If U30, c=1, otherwise, c=0. Then, the sector N=a+2 b+4c. The module of the judgment of the sector is given in Fig.4. Fig. 4. Simulation model of the judgment of the sector 2) The acting time calculation of the basic voltage vector X, Y, Z are formulated as follows sdsd3( 3 )23( 3 )2XUUUTYUUUTZU=+=+=(4) The relationship between the acting time T1, T2of the basic voltage vector and X, Y, Z is shown in Tab. I. TABLE I THE RELATIONSHIP BETWEEN T1, T2AND X, Y, Z N 1 2 3 4 5 6 T1Z Y -Z -X X -Y T2Y -X X Z -Y -Z Fig.5 shows the model of the acting time calculation of the basic voltage vector under the environment of MATLAB7.0/Simulink. Fig. 5. Simulation model of the acting time calculation of basic voltage vectors 3) The calculation of switching time First, TaTbTccan be expressed as s12a1ba2cb422TTTTTTTTTT=+=+(5) TABLE II THE SWITCHING TIME N 1 2 3 4 5 6 TaonTbTaTaTcTcTbTbonTaTcTbTbTaTcTconTcTbTcTaTbTaThe switching time can be acquired by looking up Tab.II, where Taon、 Tbon、 Tcon means the turned-on time of the three-phase upper bridge arm power component respectively. Fig.6 shows the simulation model of the calculation of switching time built in MATLAB/Simulink. Fig. 6. Simulation model of the calculation of switching time C. The Module of PMSM The mathematical model of PMSM is usually composed of stator flux linkage equation, voltage equation, electromagnetic torque equation and mechanical movement equation. The equations under d-q coordinate system can be expressed as follows: The stator flux linkage equation: dddfqqqLiLi=+=(6) The voltage equation: ddsd qqqsq dduRidtduRidt=+ =+ +(7) The electromagnetic torque equation: eqddq()Tpi i= (8) The mechanical movement equation: eLJ dTTPdt= (9) Where, ud, uqstator d-q-axis instantaneous voltage id, iqstator d-q-axis instantaneous current d, qstator d-q-axis flux linkage Ld, Lqstator d-q-axis inductance Rsstator resistance fpermanent magnet flux linkage Teelectromagnetic torque TLload torque J moment of inertia p pole-pairs Taking the algorithm of id=0 and combining the above modules, we can get the control system simulation model, which is shown in Fig.7. Fig. 7. Simulation model of the control system IV. SIMULATION RESULT Based on the established model, detailed starting and barking characteristic researches are carried out. The machine parameters, used for the simulations, are listed in Tab. . TABLE THE MACHINE PARAMETERS FOR SIMULATION Rated power 1.1kW Pole-pairs 4 Rated voltage 220V Rated speed 3000r/min Rated load 3N.m Stator resistance 2.8750 d-axis inductance 8.5mH q-axis inductance 8.5mH Magnet flux linkage 0.175Wb Setting the reference speed 3000r/min, the motor, under full-load 3N.m, starts up from zero hour. At 0.4 seconds, the motor begins to brake, since the reference speed has been set to 0 r/min. The speed-time curve and torque-time curve corresponding to this process is displayed in Fig.8 and Fig.9, respectively. The variations of three-phase currents in the stator windings with time from 0.28s to 0.3s are shown in Fig.10. And Fig.11 shows the line-voltage waveform of phase-A and phase-B from 0.25s to 0.3s. Fig. 8. Speed-time curve during the motor starting and braking Fig. 9. Torque-time curve during the motor starting and braking Fig. 10. The detail three-phase currents-time curves from 0.28s to 0.3s Fig. 11. The detail voltage-time curves from 0.25s to 0.3s It can be seen from Fig.8 that, under full-load condition, the start-up time is about 0.1s and the braking time is around 0.03s, proving that PI adjuster parameters is appropriate and the control system model is fast and stable in starting and braking. Fig.10 shows clearly that the three-phase current amplitudes are approximate equal, 20A or so, and the phase differences between the three-phase currents are 120. It is concluded that the SVPWM algorithm and the control system model is effective, providing theory basis for actual design of the control system. REFERENCES 1 Sun Ye Shu, Zhou XinYun, Li Zheng Ming. “SIMULINK simulation of space vector PWM ,”Farm machinery research, Vol. 37, No. 5, pp. 105-106, 2003. 2 Wang Xudong, Na Risha, Liu Ning, Simulation of PMSM field-oriented control based on SVPWM, 2009, pp. 1465-1469. 3 Wang Aimeng, Li Heming, Sun Pengwei, Wang Yi, Wan Shutting, DSP-based Field Oriented Control of PMSM using SVPWM In Radar Servo System, 2005, pp. 486-489. 4 Li Chuan Fang, Li Feng , Qu Ji Sheng . “Technology characteristic and optional method of the space vector pulse-duration modulation(SVPWM),”Shan Dong university Journal, 2005, pp.27-31. 5 Tengwei Yu, Ruixue Ni, Xudong Wang, Bin Zhang, A Simplified SVPWM Algorithm and its A