磁悬浮反作用飞轮无刷直流电机转矩脉动抑制策略

无磁链反馈直接转矩控制（DTC）因转矩响应速度快，为小电感磁悬浮反作用飞轮（MSRF）无刷直流电机（BLDCM）的转矩脉动抑制提供了可能，但其bang-bang控制器使电机转矩脉动较大。为解决此问题，对影响转矩脉动的换相和非导通相续流过程进行了数学建模，并得出电机转矩与绕组电流的关系，提出一种基于转矩预测的转矩控制方法，能够有效减小转矩脉动，并证明了所提策略的稳定性和鲁棒性。在采用滑模观测器（SMO）进行反电动势估计时，提出一种新的带有参数的光滑连续函数替换符号函数，有效地抑制了滑模观测器的抖振现象。仿真和实验结果表明，所提出的基于改进滑模观测器和转矩预测的改进转矩控制方法相对于传统直接转矩控制能够更好地抑制转矩脉动，而且转矩响应速度基本不变。

Torque ripple reduction strategy for magnet suspended reactive flywheel brushless DC motor

Due to its high torque response speed, direct torque control (DTC) without flux feedback makes the torque ripple reduction of magnet suspended reactive flywheel (MSRF) brushless DC motor (BLDCM) possible, which has a small inductance. However, the bang-bang controller of the DTC causes high torque ripples. To solve this problem, the mathematic models of commutation and diode freewheeling of the inactive phase were established and the relationship between torque and phase current was obtained.Then a torque prediction method based on the established models was proposed to reduce the torque ripple effectively, and the stability and robustness were proved. While estimating the back electromotive force of the BLDCM with sliding mode observer (SMO), a smooth and continuous function with one parameter was employed to replace the sign function which leads to a higher back electromotive force estimation accuracy. Simulation and experimental results show that compared to the traditional DTC, the advanced torque control method with torque prediction and advanced SMO can significantly suppress the torque ripples and has almost the same torque response speed.