Fault Diagnosis Approach for Bipolar Modular AC-AC Converter Under IGBT Open-Circuit Faults
摘要
With the increasing integration of renewable energy, low-frequency AC transmission has become a competitive candidate for high-voltage long-distance power transmission. The bipolar modular AC-AC converter (BMAC), known for its simple structure and independent control of active and reactive power, can be used in such systems. However, the switching devices in the numerous full-bridge submodules (SMs) are prone to open-circuit faults. In this study, a diagnostic method for open-circuit faults is put forward for BMAC based on the 3-sigma criterion. A fault is identified if the SM capacitor voltage lies outside the preset range. The proposed approach avoids the need for precise mathematical models and additional hardware. Simulation results confirm the validity of the presented method.