Diagnosis of inter-turn short circuit and rotor eccentricity for PMSG used in wave energy conversion

In this paper, the stator winding inter-turn short circuit and the rotor eccentricity hybrid fault of permanent magnet synchronous generators (PMSG) used in wave energy conversion is analyzed by using a coupled field-circuit method with the saturation being taken into account. The harmonic current and the vibration spectrum were used in order to investigate this kind of fault. The diagnosis system was tested over a PMSG with novel rotor suitable for middle-power wave power generation applications. The online electrical and vibration characteristics detection test was performed by using three current transformers, a digital signal processor (DSP) board, and a personal computer, including an accelerometer sensor, a vibration amplifier, and a DL750 ScopeCorder with a configurable control circuit for switch open faults of generatorside rectifier and grid-side inverter involved. Simulation and experimental results have shown that the sideband frequency currents at 25 Hz and 75 Hz, and the 17
^th
and 19
^th
order components of terminal currents can be used as fault detection criteria. Furthermore, the vibration spectrum can aid the method, being an auxiliary fault detection index.