A Comprehensive Diagnosis Method for Transistor and Current Sensor Faults in Traction Converters

The traction converter is an indispensable component in the train. Its reliability is essential for the safety and efficiency of the electric traction system. However, transistor open-circuit (OC) faults and current sensor faults in the traction converter may lead to operational risk, posing a danger to the safety. In this article, a comprehensive diagnosis method for transistor and current sensor faults is presented. First, the converter topology is introduced and the dc-link model is constructed, both OC faults and current sensor faults are analyzed. Next, the estimated value of the differential dc-link voltage is calculated, the residual is acquired and used for fault detection. Then, combining with the current directions and command signals, sampling points related to the corresponding faults are counted and normalized. The characteristics of the percentages under different fault conditions are extracted, rules are established for fault diagnosis. Finally, the traction converter platform is developed. The effectiveness and accuracy of the proposed method are validated by experimental results.