Control Method for Reducing Inrush Current in Open-End-Winding Tap-Switching Transformer with Compensating Inverter

A tap-switching transformer can serve as an effective voltage regulation circuit when used as a voltage compensator. However, it generates inrush currents because of the step changes in load voltage during tap switching. In this study, we propose an AC voltage regulation circuit that employs a series-compensating inverter to solve the tap-switching transformer problem. We connect a series-compensating inverter to supply high-quality power to the load. However, the load voltage changes in a step-wise manner during tap switching, causing an inrush current. Therefore, we propose an inrush current suppression method for the proposed circuit. The experimental results demonstrate that the tap-switching coordination control reduces the inrush current by 53.4% when compared with the case of the tap-switching transformer alone.