基于磁链函数的BLDCM无位置传感器控制方法研究

Study on a Sensorless Control Method of BLDCM Based on Flux Linkage Function

无刷直流电机(Brushless DC Motor, BLDCM)由于结构简单、功率密度高的优点得到了广泛应用。传统的BLDCM无位置传感器控制方法利用反电势过零点进行换相,存在低速时反电势难以辨识的问题,故提出了一种新型的磁链函数方法,将两个反电势做商构造磁链函数,利用磁链函数过零点判断电机换相点解决了反电势低速时难以辨识的问题。相比传统磁链函数法,提出的改进磁链函数解决了高速换相点丢失的问题。此外,还对绕组电阻、电感压降以及滤波电路带来的换相误差角度进行了分析和补偿。实验结果表明,采用提出的无位置传感器换相方法,BLDCM能够在中高速范围内实现准确换相。

Brushless DC motor(BLDCM) has been widely used due to its simple structure and high power density. The traditional BLDCM sensorless control method uses the zero-crossing point of the back-EMF for commutation, and there is a problem that the back-EMF is challenging to identify at low speeds. In this paper, a new type of flux linkage function method is proposed, which is constructed by using the quotient of two back EMFs. The zero-crossing point of the flux linkage function is used to determine the commutation point of the motor, which solves the problem of high-speed commutation point loss. In addition, the commutation error angle caused by winding resistance, inductance voltage drop and filter circuit is analyzed and compensated. The experiment results show that BLDCM could achieve accurate commutation in the range of close to the full speed and on load by using the proposed position sensorless commutation method.