A Critical Fault-Tolerant Inverter Based on Internal Evolutionary Short-Circuit Failure Mechanism of IGBT Module

Long-term and stable operation after failure is a challenge for high-reliability power converters. An extreme characteristic of IGBT is deeply explored, and a new cold-redundant inverter topology is proposed in this article. A quantity of epoxy-encapsulated IGBT modules is analyzed in short-circuit (SC) failure for critical energy. The evolution of the IGBT failure mechanism is crucial to the stability of this structure. An ohmic mode is discovered in dynamic characteristics analysis. Based on the robustness experimental test, the results revealed the characteristics of the internal structure reorganization and the evolution law of the electrical parameters under the rated current pulse stress. The epoxy-encapsulated IGBT module has a stable SC failure impedance characteristic
${R}_{{\text {sc}}}$
, with no more than 20% drift even after a 624-h continuous thermal cycle aging test. On this basis, the new cold-redundant inverter platform with this IGBT module is tested. There is only one paralleled safety leg connected in series with the faulty equipment without any additional complexity or extra cost. The full process like fault identification, isolation, structural reorganization, switching, and loading is verified and realized after the transient SC faults.