Fault-tolerant Method Based on Reconstructed Modulation for H-bridge Converter in Power Electronic Traction Transformer

A fault-tolerant method for H-bridge converter in power electronic traction transformer is proposed. This fault-tolerant mothed can ensure safe operation for H-bridge converter under open-circuit fault condition based on modulation reconstruction strategy. The faulty module can still transfer certain power. The influence of open-circuit fault on a single full-bridge circuit is illustrated, and the influence on modulation and PWM voltage is analyzed. Based on the analysis, the fault-tolerant method is given to reconstruct the modulations of both faulty module and normal modules with the change of current direction. Correctness and efficiency are validated through experimentation.