A research of combined multifunctional three phase grid-connected inverter/active power filter for PV system

With the global environmental pollution and the increasing serious energy crisis today, photovoltaic (PV) power grid-connected generation system is becoming one of the most promising renewable energy technologies. However, the PV grid-connected power generation converter is not utilized at night. In order to improve the efficiency of photovoltaic (PV) power grid-connected generation system and improve the quality of electricity power, a combined three phase grid-connected inverter/active power filter (APF) is utilized in this paper. The multifunctional inverter/APF is used as the three phase grid-connected inverter at day, and then used as APF to reduce the harmonic current at night. Reactive current and harmonic current detection method of APF, current loop controller and voltage loop controller design methods are analyzed in detail. The feasibility of control strategy and system topology is verified by the simulation results.