基于定子磁链降阶状态观测的永磁同步电机无差拍直接转矩控制系统

Deadbeat Direct Torque Control of Permanent Magnet Synchronous Motor Based on Reduced Order Stator Flux Observer

针对传统永磁同步电机直接转矩控制中存在的磁链和转矩脉动较大、逆变器开关频率不恒定的缺点。文中提出了一种无差拍的永磁同步电机直接转矩控制方案。在一个控制周期内同时精确补偿了给定磁链幅值与实际磁链幅值、给定转矩幅值与实际转矩幅值的误差,实现了磁链与转矩的无差拍控制。为解决永磁同步电机直接转矩控制系统需要转子的初始位置信息以确定定子磁链的初始值这一问题,本文通过构造定子磁链降阶观测器的方法消除初始磁链误差,使永磁同步电机直接转矩控制系统的运行不依赖转子初始位置信息。最后提出了一种适宜于无差拍直接转矩控制算法和定子磁链降阶观测器的基于转子磁链的转速辨识方法。使整个系统实现无速度传感器运行。

For the conventional direct torque control of permanent magnet synchronous motor, the flux and torque ripples are serious, and the inverter switching frequency is not constant. This paper proposes a deadbeat direct torque control scheme of permanent magnet synchronous motor. The error between the reference and actual flux amplitudes, and also the error between the reference and actual torques can be compensated accurately during a control cycle. So the flux and the torque can be controled in a deadbeat fashion. To solve this problem that permanent magnet synchronous motor direct torque control system requires the initial rotor position information to determine the initial value of the stator flux, the stator flux reduced order observer is constructed to eliminate the initial flux error. So the permanent magnet synchronous motor direct torque control system operation does not require the initial rotor position information. Finally a rotor speed identification method based on rotor flux is proposed, which is suitable for the deadbeat direct torque control algorithm and the stator flux reduced order observer. So the whole system can operate without any speed sensor.