A Sensor Fault Diagnosis Method for Single-Phase Three-Level Rectifier Used in Traction Systems

In order to improve the reliability of the single-phase three-level rectifier in traction systems, a sensor fault diagnosis method is proposed in this paper. Not only the current sensor faults is considered, the voltage sensor faults are taken into account as well. First of all, the model of DC side is built, and the estimators of one DC side voltage is constructed. Then, the voltage residual is obtained, the difference between the measured values of two voltage sensors is calculated. The residual and difference will change after a fault occurs in the current or voltage sensor, the fault can be located by the change rules. Besides, during the fault diagnosis process, only one voltage residual is required and no additional hardware is necessary. Finally, to verify the correctness of the proposed method, a simulation platform of the traction system is established, and the simulation result of different faults are obtained. The correctness is verified by the results.