Open-Circuit Fault-Tolerant Method for Three-Level Quasi-Switched Boost T-Type Inverter

The three-level quasi-switched boost T-type inverter (3L-qSBT(2)I) has been considered as a promising topology which can solve possible semiconductor faults by itself. In this inverter, traditional solution solving upper/lower switch open-circuit fault significantly increases voltage rating of upper/lower switches. This paper presents a novel fault-tolerant control method to reduce the voltage stress of upper and lower switches, in the fault condition. In post-fault operation mode, the inverter works like a two-level quasi switched boost inverter. The proposed control strategy can reduce the voltage stress on these switches by 50% when compared to the traditional control method. Comparison and simulation study are presented. The experimental results are conducted to verify the accuracy of the proposed control method.