Fault Isolation Strategy of Cascaded H-bridge Rectifier in Power Electronic Traction Transformer

As the input stage of the power electronic traction transformer (PETT), the cascaded H-bridge rectifier (CHBR) is responsible for converting the high-voltage alternating current into direct current for the next-stage DC/DC conversion. It is of great significance to study the fault isolation strategy of cascaded H-bridge rectifiers for the safe running of trains. The basic principles and control strategies of single-phase H-bridge rectifiers and CHBR are introduced. A control strategy of CHBR based on the differential voltage balance strategy (DVBS) is proposed and its effectiveness is verified. A fault isolation strategy of CHBR based on DVBS is proposed, and the effect of this strategy to isolate faults and restore the stability of CHBR is verified by simulation.