Enhanced Model Predictive Voltage Control of Four-Leg Inverters with Switching Frequency Reduction for Standalone Power Systems

This paper presents a model predictive voltage control strategy with a prediction horizon of two samples for enhanced output voltage control of three-phase four-leg inverters used for standalone power systems. The four-leg inverter is developed to deliver symmetrical sinusoidal three-phase voltages, irrespective of the arbitrary consumer load profiles. The proposed controller uses the discrete-time model of the inverter and RLC filter for two-step prediction of output voltage with fewer commutations so as to reduce the switching frequency. The control method chooses a switching state that minimizes the error between the output voltage and its reference. The proposed controller offers an excellent tracking reference with less harmonic distortion voltage for balanced, unbalanced and nonlinear loading conditions. The feasibility of the proposed control scheme has been verified by MATLAB/Simulink.