基于自适应滑模观测器无位置传感器PMSM控制方法研究

Research on PMSM Without Position Sensors Control Based on Adaptive Sliding Mode Observer

针对无位置传感器永磁同步电机控制存在的转子位置与转速估计精度不高的问题,结合自适应算法设计了一种新型的自适应滑模观测器。滑模自身机制引起的系统抖振问题是影响电机转子位置与转速估计的最大因素。为了降抖减振,采用连续的sigmoid阈值函数代替sign符号函数;提出一个反电动势自适应估计环节代替传统的低通滤波器,提高反电动势估计精度;此外为了降低转子位置及其转速的估计误差,采用锁相环对其进行估计。最后,基于200W的PMSM搭建实验平台对上述改进算法进行验证。结果表明:电机转子位置与转速估计稳态误差分别为0.129 rad、79 r/min,能够实现无位置传感器PMSM高精度控制。

In this paper,a novel adaptive sliding mode observer was proposed based on adaptive algorithm to improve the estimation accuracy of rotor position and speed of the permanent magnet synchronous motor system which has no position sensors.The system chattering caused by the sliding mode mechanism is the biggest factor affecting the estimation accuracy of rotor position and speed of the motor.Hence the sign function was replaced by the sigmoid function to reduce the chattering.Moreover,an adaptive estimation method of Back-EMF(back electromotive force)which substitutes the traditional low-pass filter was put forward to increase the estimation accuracy of Back-EMF.Then the phase-locked loop was adopted to reduce the estimation error of rotor position and speed.Finally,the experiment based on the 200 W PMSM were implemented,and the results show that the steady-state error of rotor position and speed were respectively reduced to 0.129 rad and 79 r/min,which can realize the high-precision control of PMSM without position sensors.