一种基于BUCK变换器的变结构控制系统

A Variable Structure Control System Based on BUCK Converter

针对无刷直流电机广泛存在的换相转矩脉动较大的问题,提出了基于BUCK变换器的变结构控制系统,并将其用于无刷直流电机。在母线上加入BUCK变换器,通过调节BUCK电路中驱动晶闸管开关的信号的占空比大小,来连续地调节直流母线电压,从而实现电机的转矩控制,以抑制换相转矩脉动。在分析了换相转矩脉动的产生原因后,详细介绍了通过BUCK变换器抑制换相转矩脉动的控制方法。并搭建仿真实验平台对基于BUCK变换器的无刷直流电机变结构控制系统进行仿真实验研究。仿真结果表明,该方法能够有效抑制无刷直流电机的换相转矩脉动。

Large torque ripple for brushless DC motor is widely existed. To solve this problem,a variable structure control system based on BUCK converter was investigated.We set up a BUCK converter onto the bus,and continuously adjusted the DC bus voltage by changing the size of the duty cycle of the signal which drives the thyristor switch in the BUCK circuit,thus realized the torque control of motor to suppress the commutation torque ripple. After analyzing the causes of commutation torque ripple,the control method of reducing commutation torque ripple through BUCK converter was introduced in detail.Besides,a simulation experiment platform was built to simulate the variable structure control system of brushless DC motor based on BUCK converter.Simulation results show that the commutation torque ripple of brushless DC motor can be effectively suppressed by applying the method we proposed.