基于滑模控制的无刷直流电动机直接转矩控制

为了降低无刷直流电动机的转矩脉动,增强运行稳定性和控制精准度,提出了一种基于滑模控制的无刷直流电动机直接转矩控制方法。基于无刷直流电动机的数学模型,采用超扭曲算法(super-twisting)的滑模控制器代替原有的转矩、磁链滞环比较器,分析了滑模控制器的稳定性,设计了磁链、转矩观测模型;利用空间矢量调制技术代替原有的开关表,实现了对控制系统开关频率的优化;仿真分析了改进前后两种方法的电动机输出特性。结果表明:采用滑模变结构控制提高了控制精准度,有效地抑制了无刷直流电动机的转矩脉动,滑模控制器的稳定性良好,开关频率恒定,逆变器的通断可控性得到改善。改进后的控制方法可以提高无刷直流电动机的系统性能,使电动机运行具有更好的鲁棒性和稳定性。

Direct torque control method of brushless DC motor based on sliding mode control

In order to reduce the torque ripple of the brushless DC motor, and enhance the running stability and control accuracy, a direct torque control method for brushless DC motor based on sliding mode control is proposed. Mathematical model based on brushless DC motor is established. The original torque and flux hysteresis comparators are replaced by super-twisting sliding mode controllers. The stability of the sliding mode controller is analyzed, and the flux linkage and torque observation model are designed. The original switch table is replaced by a space vector modulation technique to optimize the switching frequency of the control system.The motor output characteristics of the two methods before and after the improvement are analyzed by simulation. The analysis results show that:sliding mode variable structure control achieves improved control accuracy. The improved control method can effectively suppress the torque ripple of the brushless DC motor.Sliding mode controller has good stability, the switching frequency is constant, the on/off controllability of the inverter is good, and the improved control method advanced the brushless DC moto system ability. Motor operation has better robustness and stability.