Research on Fault Diagnosis for Output Voltage Sensors of Parallel Auxiliary Converter of EMUs

The auxiliary converter is an important component of EMUs, supplying power to the three-phase AC load of the whole vehicle. At present, the mainstream control technology of auxiliary converters in EMUs is parallel control strategy, in which the output voltage sensor is the core component. The fault-tolerant control of auxiliary converter will be occurred under the condition of sensor fault which not only have a serious risk of abnormal heat of auxiliary converter itself, but also may cause grid-connected control failure of AC power supply bus. It will affect the security and reliability of the train. To solve the problem of fault diagnosis reliability of the output voltage sensors of the parallel auxiliary converter, an effective fault diagnosis strategy based on time sequences proposed in this paper. By analyzing the operating characteristics of the auxiliary converter and the AC bus under different time sequences, the corresponding fault diagnosis strategy is developed. The result of field fault case showed that the proposed strategy can effectively diagnose the fault sensor, improves the Reliability and sensitivity of fault diagnosis of output voltage sensors, and has broad engineering application prospects.