LVRT control strategy for photovoltaic inverter based on current derating

According to grid connected standard for photovoltaic power generation system, a LVRT control strategy for photovoltaic inverter based on active current derating is proposed. First, under grid normal condition a control strategy based on antiwindup PI controller is proposed, which reduces the influence of integral saturation on current reference value; Then, a LVRT control strategy based on current reference value derating in order to reduce DC bus voltage fluctuation and smooth grid-connected current change. Finally, LVRT experiment test results on a 500kVA photovoltaic inverter shows that the LVRT control strategy can apply various grid voltage dips and achieve good dynamic, static performance, the control parameters is universal with the control strategy under grid normal condition , and the switching logic of these two control strategy under grid normal and fault condition is simple.