Influences from LCL Filter on Behaviors of Three-phase Three-level PWM Rectifier

In this paper, system description of a three-phase Neutral-Point-Clamped (NPC) rectifier is briefly given by depicting its power circuit and controller. In consideration of tracking target current and minimizing current ripples, the allowable parameters of inductor capacitor inductor (LCL) filter are calculated. The filter inductor is then adopted to investigate the influences from LCL filter on dynamic behaviors of this three-phase three-level rectifier. Based on proportional-integral control method, the simulation analysis is carried out to explore the operational behavior differences caused by the variation of filter inductor. The curves of output variables and their phase trajectories are comparatively addressed in terms of different parameters of the LCL filter. The simulated results indicate that the filter parameters has significant impacts on the operational performance of rectifier system, which implies that suitable control method is required to eliminate unexpected influences.