A Wide Range Dynamic Voltage Corrector with Short-Circuit Fault Isolation

Dynamic Voltage Corrector (DVC) with short-circuit fault isolation is proposed to improve the power quality and reliability of the power grid. The device which is composed of a bidirectional AC-DC half-bridge converter and a neutral point clamped (NPC) three-level half-bridge converter is able to correct wide range voltage sag and swelling. The topology can achieve energy feedback, so the load short-circuit fault isolation is realized with limiting current peak of filter inductor. This study analyzes working principle of the DVC, and researches the control strategy and design method of the control parameters. The compensated output voltage of the experimental prototype has good stable accuracy and fast dynamic response, which verifies the theoretical analysis and the feasibility of the control strategy.