Dynamic Hysteresis Current Control to Minimize Switching for Three-Phase Four-Leg VSI Topology to Compensate Nonlinear Load

This letter presents a dynamic hysteresis current control algorithm for a three-phase four-leg voltage-source inverter (VSI) topology. In order to improve the performance and life of the power switches of VSI, we require an optimized control technique that reduces its switching frequency. Proposed hysteresis current control method is a generalized control method that minimizes switching operations to compensate nonlinear load under both balanced and unbalanced supply voltages. It is shown that this control scheme is able to reduce the switching frequency by more than 50% compared to conventional hysteresis current control method and retain the quality of load compensation. The effectiveness of the proposed control scheme is illustrated through simulations using Power Systems Computer-Aided Design (PSCAD) 4.2.1.