Study On AC Motor Drive System Of The Electrical Vehicle

With the vehicle retention increasing dramatically in our country, energy and environment problem is becoming more and more serious. Transportation tools with low exhaust and high energy efficency are urgently needed. The electric vehicle, which is generically economic and environmental friendly, has become the most important hotspot?in transportation vehicle research worldwide. EV will become one of most important transportation tools in 21st centuries.Motor drive system is one of the key parts of vehicle and determines the performance of the whole vehicle. Since 1990's, AC motor drive system has become the mainstream drive system of EV abroad, replacing the DC drive system. At present, AC motor drive system meeting the special propulsion demands of the EV (Electrical Vehicle) is still in the stage of trial.According to multi-variable mathematical model of AC motor, this paper thoroughly studied the control technique and method of AC motor drive system of EV, using motor unification principle, energy conversion and vector control theory which is based on coordinate transformation.To achieve quick response and precision control, we adopted rotor flux field-oriented control to control the rotate speed of asynchronous motor in a similar as that of a DC motor, by the way of controlling magnetic current im and torque iT of dqO revolving coordinate respectively via vector calculation.In order to realize fleetness and high real-time performance required by the drive system of EV, we selected as core control of system the digital signal processor (DSP), TMS320LF2407 of TI company, which is specific for motor control; intelligent power module (IPM) of converter power apparatus of high performance. We also designed the main circuit and control circuit of the system, taking into consideration the electromagnetism interference (EMI) and electromagnetism compatibility (EMC) are. The dynamic and static characteristics are simulated using SIMULINK of MATLAB 6.0, which showed that the system had both good speed response and position control capacity. In this EV motor control system study we developed the hardware control system based on high-performance TMS320LF2407 DSP, and proposed a novel PWM method-Space Vector Pulse Width Modulation (SVPWM) to realize the reliable high performance control of asynchronized motor. The algorithm described in this paper can achieve favorable result.