PR Control of A Three-phase Grid-connected Inverter Under Unbalanced Grid Voltages Condition

摘要

The effective control of a grid-connected inverter (GCI) under unbalanced grid voltages condition is able to enhance the grid-connected operation ability of the inverter. This paper studies the control scheme of a three-phase GCI with proportional plus resonant (PR) regulators in the stationary αβ frame to remove the power ripples caused by the unbalanced condition and the currents of positive and negative components can be controlled directly without any decomposition. A precise and fast phase-locked loop is also introduced in this paper. Three control targets are achieved on a 2KVA experimental platform of a GCI and the experimental results agree well with the theoretical analysis.