基于间接定子量的永磁同步电动机三电平直接转矩控制

Indirect Stator-Quantities Control System of Three-Level Direct Torque Control for Permanent Magnet Synchronous Motors

针对永磁同步电动机传统直接转矩控制在低速圆形磁链运行时存在转矩和磁链脉动大的问题,采用基于间接定子量的三电平二极管中性点钳位逆变器供电的空间电压矢量调制(SVPWM)策略的直接转矩控制。首先给出了由间接定子量的方法产生控制转矩所需定子预期电压信号的方法;然后给出60°坐标系下SVPWM的设计方法,与传统算法相比,该算法能够有效地简化计算,在此基础上,通过调整冗余小矢量的作用时间来平衡直流侧两电容电压;最后,为了验证基于间接定子量的永磁同步电动机三电平直接转矩控制的算法的有效性,通过基于MATLAB/Simulink软件的仿真对比了其与传统直接转矩控制单一矢量法的控制效果,结果表明,所采用的方法能够有效改善电磁转矩的脉动、减小定子电流的谐波含量,并具有很好的动、静态性能。

To minimize the ripples of the electromagnetic torque and flux linkage produced in the conventional direct torque control（ DTC） system for permanent-magnet synchronous motors（ PMSM）,a three-level with neutral point control inverter space vector pulse width modulation（ SVPWM） strategy of DTC was proposed. Firstly,the expected voltage was produced by indirect stator stator-quantities control system. Secondly,SVPWM in 60° coordinate frame was designed in detail,which can make calculation easier compared with traditional SVPWM,then,the balance of DC-link capacitor ＇s voltages,duty ratio times of redundancy small vectors were allocated by regulating neutral point control factor. Finally,validity of PMSM DTC based on three-level SVPWM in 60° coordinate frame were verified by MATLAB/Simulink software simulation. The results show that the method can be used effectively to improve the electromagnetic torque ripple and reduce stator current harmonic content,and also has a good dynamic and static performance.