Incipient Sensor Fault Detection for Inverter Devices in Electric Railway Traction Systems

This paper proposes an incipient sensor fault detection method for three-phase PWM inverter devices in electric railway traction systems. An adaptive and sliding mode unknown input observer is designed for sensor faulty inverter system. The invariant ellipsoid is used to generate threshold. The parameters of the observer are particularly designed such that the estimation errors converge to the threshold invariant ellipsoid before the sensor fault develops to incipient fault degree, and the estimation errors exceed the threshold after the sensor fault develops to incipient fault degree. Finally, simulations based on the traction system in CRH2 (China Railway High-speed) are presented to verify the effectiveness of the proposed method.