Improved discrete sliding mode control strategy for pulse-width modulation rectifier

An improved sliding mode control utilizing repetitive control (ISMRC) is proposed for a three-phase pulse width modulation (PWM) rectifier. The proposed controller integrates the advantages of both sliding mode control (SMC) and repetitive control (RC) by implementing a structure that embeds an RC controller into the equivalent control branch of an SMC controller. Both a simulation and an experiment are conducted to compare the proposed ISMRC controller with a conventional SMC controller. It is demonstrated that the fifth harmonic distortion of the current of the PWM rectifier system is controlled at 3.3%, the power factor is close to the unit, and the effect on the DC bus voltage is effectively restrained. Therefore, the proposed control strategy can improve both the steady-state performance and the dynamic transient response of a PWM rectifier control system effectively, as well as increase the robustness of the system to load disturbances and parametric uncertainties.