无刷直流电机反电势过零法无传感器控制

Sensorless Control of Brushless DC Motor by Zero-crossing Back EMF Detection

针对无位置传感器控制的无刷直流电机转子位置检测,文章提出了一种基于反电势过零点检测转子位置的方法;通过分析计算无刷直流电机的数学模型,检测不导通相的端电压并与直流母线中点电压相比较,得到反电势过零点信号.该方法不需要虚构电机中点和低通滤波电路以及分压电路,但需要在特定PWM调制方式下得到反电动势过零点再延迟30°电角度实现换相;通过MATLAB/SIMULINK仿真实验结果表明,该方法合理、有效地检测转子位置;相对于传统的反电势过零虚构中点检测方法,该方法具有结构简单、适用范围广等优点.

According to brushless DC motor rotor position detection of positionless sensor control, this paper points out a rotor position detection method based on zero-crossing point back EMF, back EMF zero-crossing point signal is received via analysis and calculation of mathematical model of brushless DC motor and by comparison of the voltage difference detection between the floating phase terminal and the midpoint in DC bus.This method does not need the virtual midpoint of motor, low pass filtering circuit and voltage-dividing circuit but needs zero-crossing point back EMF signals in a specific PWM modulation mode and then delays 30 degree electric angle to implement commutation. MATLAB/SIMULINK simulation experiment results show that this method can reasonably and effectively detect rotor position and that this method has the advantages such as simple structure, wide application rage and so on by comparing with traditional back EMF zero-crossing virtual midpoint detection method.