基于带抽头电感准Z源网络的BLDCM控制策略

BLDCM control strategy based on tapped-inductor quasi-Z-source network

针对无刷直流电机工作时存在的转矩脉动,分别对换相区和导通区提出不同的抑制策略。换相区在桥式电路输入端接一带抽头电感的准Z源网络,利用该拓扑的高升压增益特性,在换相期间调整直流母线电压等于4倍电机反电动势,使电机关断相电流下降速率与开通相电流上升速率相等,有效抑制换相时的转矩脉动;导通区采用PWM-ON-PWM调制方法,消除了非导通相的二极管续流现象,电流波动及转矩脉动得到很好地控制。仿真结果显示,换相期间的转矩脉动降低到3.8%,导通区的电流和转矩波形较抑制前更加平稳,证明了系统在换相区和导通区都能有效降低转矩脉动。

In view of the torque ripple during the operation of BLDCM,different suppression strategies were proposed in commutation and conduction interval respectively.A tapped-inductor quasi-Z-source network was added at the front of the three-phase bridge during commutation,the DC link voltage was adjusted to equal to 4 times of the back EMF with the high boost gain characteristic of this topology,and the current decreasing rate of the outgoing phase was equal to the rising rate of the incoming phase to suppress the torque ripple effectively.The PWM-ON-PWM modulation was used in conduction interval to eliminate diode freewheeling of the non-conducting phase,and the current fluctuation and torque ripple were well controlled.The simulation results showed that the torque ripple during commutation was decreased to 3.8%,current and torque waveforms in conduction interval are more stable than before,which proved that the system can effectively reduce the torque ripple both in the commutation and conduction interval.