Torque Ripple Reduction of Nonsinusoidal Brushless DC Motor Based on Super-Twisting Sliding Mode Direct Power Control

In this article, a second-order sliding mode control (SMC), based on super-twisting algorithm, is proposed for direct power control (DPC) of the brushless dc (BLDC) motor. The proposed controller uses a super-twisting scheme that requires only sliding surface information and can handle system uncertainties and external disturbances, well. This scheme can improve the BLDC motor torque ripple by solving the disadvantages of the conventional SMC method, such as the chattering effect and high-frequency switching control. This method is simple and robust for the BLDC motor's biggest challenge, torque ripple, which does not require any voltage and current control loops or complex reference frame transformations. The simulation results of the proposed method are compared with the DPC and model predictive control (MPC) methods, which indicate the superiority of the proposed method in both the steady and transient states. Moreover, the motor parameters variation in the tracking of active and reactive power are discussed. In addition, the practical results of the proposed method in both cases of speed and load variation show the effectiveness of this method in reducing power (torque) ripple and current total harmonic distortion (THD) and increasing the system's efficiency compared to other methods.