The Improved Control Strategy of Three-Phase Four-Wire Power Supply System Based on Massive Distributed Energy

In the massive distributed new energy system, it is necessary to provide reliable power for unbalanced loads. Four-wire voltage source inverter has become a reliable bridge between source and load. This paper proposes an improved control strategy to improve power quality for four leg voltage source inverters in independent power supply system. In order to improve the output power quality of the feedback linearization control strategy and its robustness to load side disturbances and system parameter uncertainties, an online adaptive correction strategy with a gray wolf optimizer is proposed. The strategy compensates the load and phase disturbance through smooth reference adjustment to improve the quality and symmetry of voltage waveform and make the inverter output meet the existing power quality standards and indicators. The effectiveness of the proposed control method is verified by simulation and experiment, and the results show that it can still maintain the voltage waveform requirements within the output standard limits under unbalanced and nonlinear load conditions.