基于改进型滑模观测器的无刷直流电机无位置传感器控制

A Position Sensorless Control Strategy for BLDCM Based on an Improved Sliding Mode Observer

为实现无刷直流电机(brushless DC motor,BLDCM)无位置传感器控制,该文提出一种改进型的线反电势滑模观测器,为减少系统的抖振,该观测器引入了一种光滑的双曲正切函数,使得控制系统不必外加低通滤波器和相位补偿模块就可以获得平滑的线反电动势估计值,进而避免了反电势估计值的相位滞后。文中将估计得到的线反电势信号对应为3个虚拟霍尔信号,直接获得6个离散的换相信号,从而无需固定相移电路和相移角的计算。仿真和实验表明,该文所提出的方法能够准确估计BLDCM的线反电动势,实现了BLDCM无位置传感器控制。

In order to achieve position sensorless control of brushless DC motors（BLDCM）, this paper proposed an improved line back electromotive force（back-EMF） sliding mode observer（SMO）. To reduce chattering of the system, a smooth hyperbolic tangent function was employed in the observer. In this way,not only the low-pass filter and phase compensation module were eliminated, but also smooth line back-EMF signals were obtained, thus the phase lag of the estimated line back-EMF was avoided. Besides, the estimated line back-EMF signals corresponded to three virtual Hall signals, and six discrete commutation signals were obtained directly. The simulation and experimental results show that the proposed method can accurately estimate the line back EMF of brushless DC motors, the position sensorless control of the brushless DC motor can be realized.