基于占空比技术的PMSM直接转矩控制

A direct torque control strategy of PMSM based on duty ratio technology

永磁同步电机(PMSM)传统直接转矩控制(DTC)具有控制结构简单、对参数鲁棒性强的优点,但是存在较大的转矩和定子磁链波动。本文通过永磁同步电机在静止坐标系上的数学模型,推导出转矩和定子磁链变化率关系,并对转矩和定子磁链波动情况进行了详细的分析。在此基础上,提出了一种基于占空比技术的改进方案,该占空比计算方法不仅考虑了转矩和定子磁链偏差,同时还考虑到电机转速的影响。实验结果表明,该方案能有效地减小转矩和定子磁链波动以及转矩稳态误差,具有良好的动态和静态运行性能。

The traditional direct torque control (DTC) of permanent magnet synchronous motor (PMSM) has the advantages as simple control structure and better robustness, however this method presents large torque and flux ripples. This paper deduces the relation expression of the torque variation and flux variation by the mathematical model of PMSM in stationary coordinate, and then the ripples of torque and flux are analyzed in detail. Moreover, a revised DTC method based on duty ratio technology is proposed, which considers not only the torque and stator flux deviation, but also the influence of the motor speed. The experimental results show that the proposed method can reduce the torque and flux ripples effectively, as well as the steady-state error of torque, so the control system has the good dynamic and static performance.