Search-Coil Based Stator Interturn Fault Detection in Permanent Magnet Machines Running under Dynamic Condition

Interturn short circuit (ITSC) fault is a common in electric machines, which may severely damage the machines if no protective measure taken time. There are numerous diagnosis methods under steady-state condition. However, there relatively limited research on dynamic conditions. The operation of motors, such as cars, very scenario. Hence, this paper proposes search-coil based online method for detecting ITSC permanent magnet synchronous machine (PMSM) search coils placed stator circumference at equal intervals. Each coil reflects information about magnetic field its vicinity and also contains information. In paper, voltage induced by odd sideband harmonics around even carrier (2ωc±ω0) selected characteristic to be used effectively improving detected signal-to-noise ratio excluding interference counter-potential magnet. Since two adjacent one pole apart, set quadrature signals can acquired. Digital Lock-In Amplifier (DLIA) technology applied extract amplitude voltage, overcomes shortcomings traditional spectrum analysis applying non-stationary amplitudes different compared further determine occurrence rough location occurred. Experiments were conducted with six-phase PMSM demonstrating effectiveness proposed method. obtained results show that accurately fault.