表贴式永磁同步电机直接转矩控制变幅值预测控制研究

基于以电压矢量幅值为变量的表贴式永磁同步电机(SPMSM)磁链和转矩方程,采用预测控制计算得出施加不同电压矢量幅值的下一时刻磁链和转矩值,选择使磁链和转矩误差目标函数最小的电压矢量幅值作为最优值,从而确定下一时刻施加的电压矢量。仿真结果表明:在电压矢量变幅值预测下,SPMSM直接转矩控制(DTC)系统运行良好,定子磁链轨迹为理想圆,磁链和转矩均符合控制要求,转速跟踪良好,定子电流波形正弦。预测控制需要从备选电压矢量幅值集合中选择最优幅值。理论上,备选电压矢量幅值个数越多,系统优化效果越好,但也带来更大的计算负担。研究了9种等分电压矢量情况下变幅值预测控制系统的控制效果。根据控制效果和计算负担,提出变幅值预测控制将电压矢量幅值三等分较为理想。

Predictive Control with Variable Amplitude of Voltage Vector of Surface Permanent Magnet Synchronous Motor Direct Torque Control System

Based on the expressions of flux and torque of surface permanent magnet synchronous motor (SPMSM) direct torque control (DTC) system using the amplitude of applied voltage vector as the variable, the values of stator flux and torque at the next sampling point after applying voltage vector with different amplitude were given. The object function of flux error and torque error was proposed. The predictive control would select the optimal amplitude of voltage vector to minimize the object function. Simulation results showed that the PMSM DTC system under the control of proposed strategy worked properly. As the predictive control selected the optimal voltage vector from aggregate of voltage vectors, more voltage vectors would lead to better control performance, at the cost of heavier calculation burden. Control performances of SPMSM DTC system were given using 9 methods of dividing voltage vectors. According to control performance and calculation burden, dividing voltage vectors into three equal parts was an ideal way.