纯电动汽车用内置式PMSM的MTPA-FW控制算法对比研究

Comparative Research of MTPA-FW Control Strategy for IPMSM Used in Electric Vehicles

以一台25 kW电动汽车用内置式永磁同步电机作为被控对象,分别使用梯度下降法、电流超前角β法对比分析,实现了弱磁控制。在整个控制系统中,2种算法均使用了电流、转速和电压三闭环反馈控制,以定子相电压Us对变频器直流侧母线电压Udc的利用率为基础,采集电流调节器ACR输出的交/直轴电压U_(dq),与定子相电压最大值Usmax相比较组成反馈电压控制环,经积分调节器,最终得到修正后的交/直轴电流。与反馈的交/直轴电流比较后的差值,作为电流调节器ACR的输入。在t=0.2 s时刻,负载转矩由80 Nm阶跃到20 Nm,转速由额定转速3000 r/min阶跃到最高转速12000 r/min,由转速曲线可以看出,采用2种不同弱磁调速算法,均可以实现具备4倍弱磁调速能力。仿真证明了弱磁控制算法的合理性,实现了电磁转矩与转速的快速跟踪,以及较小的电流与转矩纹波,并初步搭建了动力系统平台,为后续试验提供理论依据。

A 25 kW interior permanent magnet synchronous motor （IPMSM） was selected as controlled object in this paper. Comparative analysis of gradient descent method and current leading angle/3 method were carried out, which were used to fulfill the flux weakening control. Triple close loop control of speed, current and voltage was realized in three control algorithms. Based on the utilization ratio of stator phase voltage rela- tive to the DC side bus voltage of inverter, the difference between the dq-axis voltage Uaq and the maximum value of stator phase voltage Usmax was taken as the input of integration regulator. Finally the revised dq-ax- is current are obtained. It took the difference between the revised dq-axis current and the its feedback value as input of current regulator. A step load torque from 80 Nm to 20 Nm and a step speed from rated value 3000 r/rain to maximum value 12000 r/rain were applied to the model at time 0. 2 s. From the simulation re- sults, find that the designed control system used three different algorithms all can fulfill four times flux weak- ening speed control. Therefore, two algorithms are reasonable. The simulation results show that velocity and torque can quickly track the given value from the aspect of dynamic response and stability, which have great application value in engineering.