A New Mitigation Strategy of AC-side Active Power Fluctuation under Three-phase Unbalanced Grid Conditions

Under three-phase unbalanced grid, a double-line frequency fluctuation component is contained in the AC-side active power of the inverter. To eliminate this component, this paper a new active power fluctuation mitigation strategy developed on the basis of conventional virtual phase-current regulation (VPCR) with fewer control parameters. The improved VPCR revealed in this paper was analyzed in comparison with the conventional VPCR in theory under identical three-phase voltage drop scenarios. An equivalent power governance outcome is ensured by an improved VPCR method. To address the absence of VPCR parameter configuration theory, a flexible control parameter design methodology is presented using the particle swarm optimization (PSO) algorithm. The paper primarily concentrates on managing output active power ripple in a three-phase three-wire grid-connected inverter considering three-phase asymmetrical grid. The improved VPCR theory is confirmed in Matlab/Simulink simulation, and the active power ripple transmitted by the inverter can be entirely removed.