Flexible Active Power Control of Distributed Power Generation Systems During Grid Faults

The increasing penetration of distributed power generation into the power system leads to a continuous evolution of grid interconnection requirements. In particular, active power control will play an important role both during grid faults (low-voltage ride-through capability and controlled current injection) and in normal conditions (reserve function and frequency regulation). The aim of this paper is to propose a flexible active power control based on a fast current controller and a reconfigurable reference current selector. Several strategies to select the current reference are studied and compared using experimental results that are obtained during an unsymmetrical voltage fault. The results of the analysis allow selection of the best reference current in every condition. The proposed methods facilitate multiple choices for fault ride through by simply changing the reference selection criteria.