Observer-based fault-detection of broken rotor bars in traction motors

In this paper, an observer-based approach is used to detect the fault of broken rotor bars in three-phase squirrel-cage traction motors of CRH5 electric multiple units(EMU). Firstly, the healthy and faulty models are established. Then, the faulty models are divided into two subsystems such that the first subsystem has the fault of broken rotor bars but without load disturbance and the second subsystem has load disturbance but is absent from faults. According to the special form of subsystems, a Luenberger observer is designed for the first subsystem to detect the broken rotor bars and a SMO is proposed to eliminate the uncertainties of load disturbance. The stability of proposed observers is proved by Lyapunov function and the sufficient condition is expressed as linear matrix inequalities (LMIs). Eventually, simulation results are shown to illustrate the effectiveness of the proposed fault-detection method.