Fast voltage recovery method based on DC bus voltage change after LVRT

At present, the researches on abnormal voltage ride-through of photovoltaic power mainly focus on the control method during voltage fault, and few researchers pay attention to whether the transition stage after voltage fault meets the requirements. Aiming at the phenomenon that after the photovoltaic power has successfully ridded through the low or high voltage faults the recovery speed of DC bus voltage is slower than that when the fault occurs, the operation state change process of the photovoltaic power encountering abnormal voltage faults is analyzed from the electrical level in this paper firstly. And based on this, the necessity and working principle of abnormal voltage ride-through control strategy are introduced. Then, according to the P-U U curve of the photovoltaic array and the change principle of the inverter DC bus voltage, the reasons for this phenomenon are analyzed from two angles. Finally, a method that can effectively improve the recovery speed of the DC bus voltage is proposed. The method is verified by simulation under various working conditions, which provides a new method for improving the abnormal voltage ride-through performance of photovoltaic power.