Improvement of DC and AC side performance of renewable source inverters under fault conditions

This paper proposes a novel DC-side controller for grid-connected voltage source converters during asymmetrical faults. The controller is based on a modified second order generalized integrator (SOGI). The main objective is to mitigate the second order harmonic voltage oscillation on DC link as well as the positive sequence third-order harmonic current injection into the AC grid, due to negative sequence voltage on the converter AC terminals.