基于虚拟中性点的无刷直流电机无位置传感器控制关键问题研究

Theoretical Research on the Virtual Neutral Point Based Brushless DC Motor Sensorless Control Strategy

深入分析了无刷直流电机采用电角度导通、PWM调制方法下,如何通过定子外接并联电阻网络的中性点(虚拟中性点)相对直流母线中点的电压信号(虚拟中性点信号)获取转子位置信息;对虚拟中性点信号中直流分量的产生作了深入的理论分析,并通过仿真分析证实了上述理论结果.

This paper presents theoretical analysis on virtual neutral point based sensorless control strategy of brushless DC motor （BLDC motor） with nonideal back electromagnetic force （back EMF） waveform. As opposed to other papers on this topic,instead of the assumption of rigid trapezoidal back EMF waveform a harmonic representation is proposed,which is able to model the nonideal characteristics of the BLDC motor. The theoretical relationship between PWM duty cycle and the DC component of the position signal is derived. Computer simulation and experiments are carried out to verify the proposed theoretical analysis.