The Direct Torque Control of Brushless DC Motor Based on Sliding Mode Variable Structure

Abstract

Aiming at the problem of slow response speed and poor anti-interference ability using the traditional PI control in the direct torque control strategy of brushless DC motor (BLDCM), the direct torque control (DTC) of the BLDCM based on the sliding mode change (SMC) structure is proposed. In the BLDCM DTC system under the new flux linkage set mode, the traditional PI control is replaced by the improved SMC control to realize the new torque set mode and realize the DTC of the BLDCM. Firstly, the integral sliding mode surface is used instead of the traditional linear sliding mode surface to optimize the continuity of the SMC structure and reduce the high-frequency perturbation caused by the differential phase, thus reducing the smooth torque and system steady-state error. Secondly, the system is simulated by MATLAB/SIMULINK; the set torque of the improved SMC is the most stable; and the speed response curve is smoother. Finally, the construction of the BLDCM test platform is completed. The experimental results show that in the BLDCM DTC control system of the new flux linkage set mode, based on the improved SMC, the system has faster response speed and stronger anti-interference, and shows stronger dynamic and static performance.