Grid voltage sags control strategy for photovoltaic inverter based on adaptive dynamic reactive power compensation

According to national standard GB/T 19964-2012 “Technical requirements for connecting photovoltaic power station to power system”, a grid voltage sags control strategy for photovoltaic inverter based on adaptive dynamic reactive power compensation is proposed. First, voltage and current dual loop control strategy for photovoltaic inverter is adopted when grid voltage is normal, voltage sags is detected by monitoring positive sequence component of grid voltage. And then, based on the traditional voltage and current dual loop control strategy for photovoltaic inverter, a novel grid voltage sags control strategy is proposed, which uses PIR current controller and adaptive reactive power regulator based on sag depth of positive sequence component of grid voltage. Finally, LVRT experiment test results on a 500kVA photovoltaic inverter shows that the voltage sags control strategy can achieve good dynamic performance, and fast, accurately realize adaptive dynamic reactive power compensation during low voltage ride through.