An Open-circuit Fault Localization Method of a Cascaded H-Bridge Converter Based on The Capacitor Voltage and The Grid Current

Unexpected open-circuit (OC) faults are a significant problem in cascaded H-bridge (CHB) converters and can cause secondary failure of other components. Therefore, it is important to localize the OC fault quickly. This paper proposed an efficient localization method for the OC fault in the CHB converter. Firstly, the operation mechanisms are analyzed under the healthy and faulty state of a CHB converter, and the grid current and the DC capacitor voltage are selected as parametric to locate OC faults. Then, the simulation model is built to validate the feasibility of fault localization using these two parameters. Finally, an OC fault localization strategy based on the capacitor voltage and the grid current is proposed, which is used to localize the OC fault in only two steps.