无刷直流电机改进型SEPIC电路研究

无刷直流电机在换相过程中产生的转矩脉动,已严重阻碍其在航空、航天等尖端领域的广泛应用。通过研究无刷直流电机在换相过程中产生转矩脉动的成因,提出了一种改进的无刷直流电机驱动系统电能变换器拓扑结构,该拓扑结构在传统单端初级电感变换器的基础上嵌入一个电容与二极管的并联电路,有效提高了输出电压,减小了开关电压应力。同时在系统非换相运行过程中根据变化的速度调整电压,以达到直流侧输出电压与反电动势成正比的目的,从而抑制换相转矩脉动。实验结果表明,该电能变换器拓扑结构能有效应用于无刷直流电机驱动系统,电机在不同速度阶段换相转矩脉动都得到明显抑制。

Research on modified SEPIC circuit of brushless DC motor

The torque ripple of brushless DC motor (BLDCM) generated during the commutation process seriously limits the applications in high precision system, such as aviation and aerospace. By analyzing the cause of the torque ripple, a modified single ended primary inductor converter (SEPIC) topology of BLDCM drive system is presented, in which a capacitor in parallel with a diode circuit is embedded. Compared to classical SEPIC converters, high static gain and low switching voltage stress can be achieved. Meanwhile, the voltage is adjusted according to the speed of the motor during non commutation period. As a result, the back electromotive force (EMF) is proportional to the DC input voltage, thereby, the torque ripple is suppressed. The experimental results show that the proposed topology can be effectively applied to BLDCM drive system, and significantly reduce the commutation torque ripple under different operating speeds.