Unified Control Method for Active Power Filters-Photovoltaic Inverters under Capacity Constraints

With the continuous advancement of renewable energy, the power system is exhibiting new characteristics. Photovoltaic (PV) inverters, as an important component of the power grid nowadays, are playing an increasingly significant role in power transmission. Faced with complex wideband harmonic characteristics, a novel unified control method for PV-active power filters (APF) inverters under capacity constraints is proposed. This method enables PV inverters to simultaneously provide active power and suppress the harmonic. When the current capacity of the PV inverter is limited, by following the principle of low-frequency priority, the inverter capacity could be maximally utilized to prioritize the mitigation of low-frequency harmonics which pose greater harm to the grid. This method could provide theoretical basis for future photovoltaic inverter designs and assist in establishing new power systems with good power quality.