基于滑模变结构的永磁同步电机直接转矩控制

The PMSM DTC Based on Variable Structure Sliding Mode

为解决传统永磁同步电机直接转矩控制中存在的电流、磁链和转矩脉动较大、逆变器开关频率不恒定、系统低速运行时难以精确控制以及因转矩脉动引起的高频噪声等问题,文中将滑模变结构控制策略引入永磁同步电机直接转矩控制中。用转矩和磁链2个滑模控制器来替代传统直接转矩控制中的2个滞环调节器,其输出实现空间电压矢量调制,保证了逆变器开关频率恒定。实验结果表明,这种新型控制策略能极大地减小传统直接转矩控制中存在的电流、磁链和转矩脉动,有效地抑制高频噪声,实现逆变器开关频率恒定,同时仍保持直接转矩控制固有的转矩快速响应的特征和对系统参数摄动、外干扰、测量误差以及测量噪声具有鲁棒性强的优点,有效地改善了系统的动、静态运行性能。

To solve those problems associated with conventional direct torque control（DTC） of permanent magnet synchronous motor（PMSM）, such as high current, flux and torque ripple, variable switching frequency, difficulty to accurately control at very low speed and the high freqaency noise caused by high torque ripple, a new variable structure sliding mode（VSS） control strategy was proposed in this paper. Two hysteresis regulators in the conventional DTC system were substituted by the flux and torque VSS controller respectively. The output of VSS controllers makes space vector modulation（SVM） possible, which further ensures the inverter switching frequency to be fixed. Experimental results verified that the proposed control scheme significantly reduces current, flux and torque ripple, effectively suppresses high-frequency noise, preserves quickly dynamic torque response merit, and shows robust to motor parameter uncertainty, disturbance measuring error and measuring noise, which effectively improves dynamic and static operation performance.