基于优化滑模观测器的无刷直流电机变结构直接转矩控制

Variable structure direct torque control for BLDCM based on optimized sliding mode observer

本文提出一种由一个优化滑模观测器及一个变结构控制器组成的直接转矩控制系统,应用于永磁无刷直流电机。滑模观测器用来获取绕组反电动势,为减小系统抖振,引入连续光滑的反正切函数,并且证明了观测器的收敛条件及稳定性。然后以转速误差为基准建立滑模切换面,构造出变结构控制器,得到转矩控制的参考值。最终通过转矩误差并参考霍尔位置信号选择合适的空间电压矢量,完成直接转矩控制。该方案的控制效果能够不受制于电机参数变化及干扰影响,具有很强的鲁棒性。实验结果证明了该方案的正确性及有效性。

Direct torque control scheme,composed of a sliding mode observer（ SMO） and a variable structure controller,is presented for brushless direct current motor（ BLDCM）. The SMO is used for the estimation of back electromotive force,a continuous smooth arc-tangent function is introduced in the observer in order to weaken chattering phenomenon,and then the sliding and convergence condition is proved. The required torque can be obtained through the variable structure controller,whose sliding surface is based on rotor speed error. In the last step of direct torque control,appropriate space voltage vector is selected by the output of torque controller. The scheme is immune to the parameter’s variation and external perturbations. Experiment results show the correctness and effectiveness of the proposed scheme.