无刷直流电机无位置传感器转子位置自检测复合方法

基于对定子铁心饱和法和滑动模态观测器法转子位置自检测原理和特性的讨论,提出了一种能在全速范围内(包含零速在内)实现转子位置准确检测和控制的复合方法.零速时采用定子铁心饱和法判断转子初始位置并起动,低高速时设计了一种新的准滑动模态观测器控制算法,它将反电动势估算值反馈到定子电流的观测计算中,相比传统的滑模观测器算法,它可以通过选择合适的反馈值提高转子位置角的估算精度和系统的稳定性,并且切换函数采用饱和函数代替开关函数,可以通过选择合理的边界层厚度有效地削弱抖振.以一台表面式无刷直流电机为对象进行实验,实验结果表明该转子位置自检测复合方法能够在全速范围内有效地估算转子位置信息,是实现无刷直流电机无位置传感器运行的一种实用方法.

A Hybrid Approach of Sensorless Rotor Position Self-Sensing for Brushless DC Motor

Based on the detailed discussion of the basic principles and merits for two methods, a hybrid rotor position self-sensing approach is investigated by combining the stator core saturation method and sliding mode observer method. To detect the initial rotor position at standstill, a approach making use of the magnetic saturation characteristic of the stator core is presented. To detect the rotor position at low speed and high speed, a new algorithm of the quasi-sliding mode observer is designed. In order to increase the precision of the rotor position estimation and the stability of the system, the estimated back electromotive force was feedback to current observer. In order to solve the chattering problem existed in traditional sliding mode observer, the sign function is replaced by a saturation function. The experimental study in an surface brushless dc moto(rBLDC)using the hybrid approach is carried out with success. The results show that the proposed sensorless control algorithm is valid and is suitable for the sensorless control in a wide speed range, including zero-speed.