Current Control Assisted and Non-Ideal Proportional-Resonant Voltage Controller for Four-Leg Three-Phase Inverters with Time-Variant Loads

In this paper a novel control strategy for four-leg three-phase voltage source inverters (VSI) supplying time variant loads is proposed. Designed control scheme is composed of three parts: A feed-forward current compensator; Inverter main Proportional-Resonant (PR) voltage controller; and inverter output current controller. The PR controller is employed for regulating the output voltage of inverter to produce a symmetrical balanced three-phase voltage under different loading conditions such as balanced, unbalanced, linear, non-linear variant loads. The inverter current control loop designed with state feed-back methods improves the system response. The performance of proposed control strategy is studied under different loading conditions. Simulation results depict marvelous performance of the proposed controller in dynamic and steady states.