无刷直流电机转矩磁链强耦合特性分析

Analysis of strong coupling between torque and flux linkage of brushless DC motor

两相导通无刷直流电机(BLDC)由于存在关断相、非正弦以及转子位置与驱动信号有严格对应关系等特点使得其直接转矩控制(DTC)的实现方法有其特殊性。研究并分析了两相导通条件下无刷直流电机定子磁链和电机转矩的变化规律以及二者之间的相互影响关系,指出由于定子磁链与电机转矩之间存在一一对应的强耦合关系,磁链闭环的存在会严重影响转矩控制效果,对于两相导通的BLDC DTC系统,在其实现时应当省去磁链环而采用纯转矩环控制方法。在一套无刷直流电机实验平台上对不同条件下的定子磁链和转矩变化情况进行了对比实验分析,实验结果验证了理论分析的正确性和实现方法的可行性。

Due to the turn-off phase,nonsinusoidal currents and strict relation between rotor position and driving signals, the implementation of direct torque control (DTC) for two-phase conduction brushless DC motor (BLDC) shows its characteristics. This paper analyzed the interaction between the stator flux linkage and torque. Due to the strong coupling between the stator flux linkage and torque, the existence of flux linkage control loop affected the torque control effect seriously. Therefore, the flux linkage control loop was eliminated and pure torque loop was adopted in BLDC DTC implementation. The experiments were carried out to compare different implementations on a BLDC experiment platform. The experimental results verify the correctness of the theoretical analysis and the feasibility of the implementation method.