A Minimally Switched Control Algorithm forThree-Phase Four-Leg VSI Topology toCompensate Unbalanced and Nonlinear Load

In this paper, a minimally switched control algorithm for a three-phase four-leg voltage source inverter topology is proposed for compensation of unbalanced and nonlinear loads. An optimized control technique is necessary for the three-phase four-leg topology, otherwise it requires higher switching operations of the switches in the voltage source inverter for tracking three-phase and neutral currents through conventional hysteresis band control. In the paper, a control technique has been formulated and its effect of reducing the switching frequency over a period of time has been studied and verified. A simulation study of three-phase, four-wire compensated system is carried out using Matlab/Simulink to validate the proposed method. Detailed experimental results presented further confirm the efficacy of the proposed control.