The Adaptive Power Compensation Strategy of Soft Open Point to Support Bus Voltage Under Faults

The fault ride-through strategy is indispensable for ensuring the seamless operation of grid-connected power electronic converters. However, the necessary current to uphold bus voltage, a primary objective of fault ride-through strategies, can vary under different fault conditions. Through an analysis of the correlation between the output current of the back-to-back type soft open point (SOP) and the bus voltage, an optimal compensation current is introduced. This leads to the revelation of the power compensation strategy requirements for the SOP to efficiently support bus voltage. Additionally, three adaptive power compensation strategies are proposed, involving disturbance injection, parameters’ value estimation, and a combination of these methods. The strengths and weaknesses of these proposed power compensation strategies are compared concurrently. Simulation results validate the effectiveness of these proposed approaches, with their characteristics summarized.