Sensor Fault Diagnosis And Fault Tolerant Control For Electric Traction PWM Rectifier

The single-phase PWM rectifier is the main component of the electric traction converters.Once unexpected failure occurs in the sensors of the system,the close-loop control performance and the operation safety of the electric locomotive will be affected.In this paper,an online fault diagnosis and fault tolerant control algorithm is proposed for single-phase PWM rectifier system.System faults can be rapidly and accurately diagnosed,and the operation of system can be maintained without halting.The mathematical model of the single-phase PWM rectifier is established.The double-loop control system is designed,and the grid side current loop and DC-link voltage loop are set as the inner loop and outer loop,respectively.PI controllers are used in the double-loop control.The intermediate DC circuit of the electric traction converter is designed.The LC resonance circuit is utilized to filter the 100 Hz ripple voltage on DC side.The effectiveness of the control system under load variation is verified by simulation results.The grid side current and DC-link voltage Luenberger observer and sliding mode observer are designed and compared in simulation.The observation error and the magnitude of fluctuation under load variance of sliding mode observer are less than Luenberger observer.Sensor fault diagnosis and fault tolerant control scheme is proposed,and the sliding mode observer is used to produce analytical redundancy.By comparing residuals with thresholds,the faulty sensor can be detected.System reconfiguration is realized by replacing the measured values from faulty sensor with observed values.The high power electric traction PWM rectifier is established under MATLAB/Simulink.The open-circuit fault and gain deviation of grid side current sensor,and the noise abnormity of DC-link voltage sensor are simulated.The effectiveness of the proposed algorithm is validated by the simulation results.The 4kVA experimental platform of the single-phase PWM rectifier is established,and the main circuit,IPM drive circuit,signal acquisition circuit,and zero-crossing detecting circuit are designed in details.The three types of faults mentioned above are simulated to verify the effectiveness and reliability of the proposed scheme.