A unified power controller for photovoltaic generators in microgrid

The non-dispatchable energy output of PV generators has an adverse effect on the stability of microgrid especially capacity-limited microgrid with high PV penetration. To solve this problem, a unified power control strategy for PV generators is proposed to mimic the performance of synchronous generator (SG) in power system. As a supplementary supply, fuel cell is equipped in the PV generator to reduce the DC voltage ripple and supply a virtual electrical inertia as well. This proposed PV generator is regulated by the conventional control algorithm for SG so that it can contribute to the voltage and frequency regulation in an islanded microgrid while it can correct power factor when the microgrid connects to the utility. This control strategy for PV generators has been verified by the simulation study. The simulation results show that it has excellent performance in tracking the maximum solar power, participating voltage and frequency control, sharing the load and correcting the power factor.