基于无差拍的永磁同步电机无传感器控制策略

针对永磁同步电机直接转矩控制系统中存在转速和转子位置观测精度不高、转矩脉动较大等问题,提出一种基于无差拍的永磁同步电机无传感器控制策略。设计基于变指数趋近律和锁相环技术相结合的新型滑模观测器,采用变指数趋近律提高反电动势观测精度并证明其稳定性,用连续函数取代符号函数降低抖振,结合锁相环技术提取转速及转子位置信息。基于此,建立电机离散化模型推导出磁链、转矩无差拍控制律,设计无差拍控制器进一步削弱抖振,提高系统控制性能。仿真结果表明:该策略能准确观测转速和转子位置,有效抑制磁链、转矩的脉动,提高系统动态性能。

Sensorless Control Strategy of Permanent Magnet Synchronous Motor Based on Deadbeat

To solve the problems of low precision of the observation of speed and rotor position and large torque ripple in the direct torque control system of permanent magnet synchronous motor, a new sliding mode observer based on the combination of variable exponential approach law and phase-locked loop technique was proposed. Variable exponential approach law was used to improve the accuracy of back EMF observation and proved its stability. Switching function was replaced by continuous function to reduce chattering. Phase-locked loop technology was applied to extract speed and rotor position information. On this basis, the motor discretization model was established to derive the flux linkage and torque deadbeat control law. The deadbeat controller was designed to furtuer alleviate chattering and improves the system control performance. The simulation results show that the strategy can observe the rotational speed and rotor position accurately, suppress the ripple of the flux linkage and torque effectively, and improve the dynamic of the system.