车用永磁同步电机MT坐标系下DTC控制

DTC in MT coordinate system for permanent magnet synchronous motor used in electric vehicle

针对直接转矩驱动技术在电动汽车动力系统应用中存在的低速转矩脉动和该动力系统对恒功率调速范围要求较高的问题,提出了一种新型永磁同步电机MT坐标系下直接转矩控制系统.该系统工作在与定子磁链同步旋转的参考坐标系中,采用改进式MTPA控制实现参考磁链的计算,利用定子磁链控制器所产生的磁链误差积分实现磁链估算.采用不同的电压矢量对逆变器的电压饱和所产生的磁链估算误差进行补偿,从而提高磁链估算精度.仿真结果表明,该系统有效减小了低速转矩脉动,拓宽了调速范围.

Aiming at the problem that the low-speed torque ripples exist in the direct torque drive technology in the application of electric vehicle power system and the power system has high requirements in the speed regulation range for the constant power, a novel direct torque control （DTC） system for the permanent magnet synchronous motor （PMSM） in MT coordinate system was proposed. The proposed system worked in a reference coordinate system which would synchronously rotate with the stator flux linkage, and an improved MTPA control was used to realize the calculation of reference flux. In addition, the flux estimation was realized with the flux error integral generated by the stator flux controller. Besides, the flux estimation errors generated by the voltage saturation of inverter were compensated in the proposed system with different voltage vectors to enhance the accuracy of flux estimation. The simulation results show that the low-speed torque ripples can be effectively reduced and the speed regulation range is widened in the proposed system.