基于两级滤波的改进滑模观测器PMSM无速度传感器控制

Improved sliding mode observer PMSM speed sensorless control based on two-stage filter

针对永磁同步电动机(permanent magnet synchronous motor,PMSM)伺服系统中由滑模观测器引起的位置估算误差以及抖振问题,提出了一种改进的两级滤波滑模观测器。首先,根据PMSM的数学模型,设计了利用传统滑模观测器估计定子电流和反电动势的估计算法;其次,分析了传统滑模观测器在PMSM伺服系统应用中的不足;再次,提出了一种新的饱和函数以代替传统的符号函数,改进了滑模观测器的控制律;最后,通过变截止频率滤波器和卡尔曼滤波器组成的二级滤波器,得到PMSM转子更精确的位置估计信息。利用Matlab,对使用了传统观测器的系统和使用改进的观测器的系统分别进行了仿真,仿真结果表明:与使用了传统观测器的PMSM伺服系统相比,使用了改进观测器的PMSM伺服系统转速误差更小、估算结果更准确。

Aimed at the problem of position estimation error and buffeting caused by sliding mode observer in permanent magnet synchronous motor(PMSM)servo system,an improved two-stage filter sliding mode observer was proposed.Firstly,according to the mathematical model of PMSM,the estimation algorithm of stator current and back electromotive force using traditional sliding mode observer was designed.Secondly,the shortcomings of traditional sliding mode observer in the application of PMSM servo system were analyzed.Then,a new saturation function was proposed to replace the traditional symbolic function,and the sliding mode observer control law was improved.Finally,a two-stage filter composed of variable cutoff frequency filter and Kalman filter was used to obtain more accurate position estimation information of PMSM rotor.The system with traditional observer and the system with improved observer were simulated with Matlab respectively.The simulation results show that compared with the PMSM servo system with traditional observer,the rotational speed error of the PMSM servo system with improved observer is smaller and the estimation results are more accurate.