A Modified Overmodulation SVPWM Method for T-Type Inverters Under Open-Ciruit Faults with Deficient Voltage Vector Sectors

This paper proposes a modified overmodulation method for enhancing fault tolerance (FT) in T-type inverters under open-circuit faults in half-bridge switches. The method boosts the magnitude of the reference voltage to compensate for the voltage drop in the faulty phase. Conventional FT control strategies typically suffer from a reduced available voltage range under fault conditions, which limits their effectiveness in maintaining normal operation. By contrast, the proposed method utilizes an extended modulation range through overmodulation, allowing for a more robust voltage output even in the presence of faults. This enhancement contributes to improved performance with only a single additional relay. The effectiveness of the proposed strategy is validated through simulation results.