一种抑制非理想反电势的BLDC电机转矩脉动的方法

A strategy of torque ripple minimization for BLDC motors with nonideal back EMF

转矩特性是电机性能的重要指标,而抑制转矩脉动是无刷直流机(BLDC motors)控制领域中的关键技术之一。本文针对非理想反电势的无刷直流机,对转矩脉动谐波构成进行了推导,分析了转矩脉动和反电动势谐波、电流谐波的关系,提出了一种基于离线反电势测量的优化电流算法,结合空间电压PWM,实现了抑制转矩脉动的电流闭环控制。仿真和实验证明,该方法可以显著抑制转矩六次谐波,是一种有效的改善无刷直流机转矩性能的方案。

Torque ripple minimization is one of main research fields of BLDC motors. Nonideal back EMF usually induces more distinct torque ripple rather than commutation torque. As improving motor design is not easy, optimizing current reference is an effective way to minimize toque ripple. In this paper, relationship between current, back EMF and torque harmonics is analysed . A harmonic-injection arithmetic based on off-line back EMF is introduced and voltage space vector PWM is applied to eliminate torque harmonics. Simulated and experimental results are presented and it is proved that the new control strategy obviously improves torque characteristic for BLDC motor with nonideal back EMF.