Sliding-mode control for three-phase PWM inverter via harmonic disturbance observer

Load uncertainties and harmonic disturbance are important issues in three-phase PWM inverter control. In this paper, a harmonic disturbance observer is developed to estimate the mismatched periodic disturbance which is produced by load uncertainty in the three-phase PWM inverter. Based on the estimation of disturbance, a special sliding-mode control (SMC) algorithm is designed to deal with the mismatched disturbance. The proposed harmonic disturbance observer can take advantages of the information of the periodic disturbance, thus the controller can obtain more accurate control signal for the inverter system. Simulation results show that the proposed method is able to attenuate the mismatched periodic disturbance and exhibits a better control performance.