基于改进型离散滑模观测器的表贴式永磁同步电机无位置传感器控制

Sensorless Control of SM-PMSM Based on Improved Discrete Sliding Mode Observer

传统离散滑模观测器由于在滑模面两侧趋近速度不同,存在十分严重的抖振现象。针对表贴式永磁同步电机无位置传感器控制系统,提出了一种改进型离散滑模观测器,基于趋近律设计了离散滑模观测器,将估计反电势作为反馈项,从根本上解决了该种抖振。为了避免低通滤波器所带来的相位延迟,采用自适应反电势滤波器得到了反电势估计值。将反电势估计值输入归一化锁相环,得到转子位置信息。分析了归一化锁相环在电机加减速过程中存在稳态误差的原因,并对其进行补偿。仿真结果表明,观测器输出的电角度估计误差在±0.4°以内,转速估计误差在±1.5r/min以内,验证了改进型离散滑模观测器的有效性。

Due to different approach speeds on both sides of the sliding mode surface, traditional discrete sliding mode observers have very serious chattering phenomena. In this paper, an improved discrete sliding mode observer is proposed for the sensorless control system of surface mount permanent magnet synchronous motor(SM-PMSM). To solve this kind of chatter, the discrete sliding mode observer is designed based on the approach law and the estimated back-EMF is used as feedback. In order to avoid the phase delay caused by the low-pass filter, an adaptive back-EMF filter is used to obtain the back-EMF estimated value. The estimated value of the back-EMF is input into the normalized phase-locked loop to obtain the rotor position information. The causes of steady-state error of the normalized phase-locked loop during the acceleration and deceleration of the motor are analyzed, and then the steady-state error is compensated. Simulation results show that the electric angle estimation error of the observer is within ±0.4° and the speed estimation error is within ±1.5 r/min, which proves the effectiveness of improved discrete sliding mode observer.