Diagnosis of a Permanent Magnet Synchronous Generator using the Extended Kalman Filter and the Fast Fourier Transform

The most common faults which can affect a Permanent Magnet Synchronous Generator are the rotor demagnetization, eccentricity (static, dynamic and mixed) and inter-turn short circuit. Their effect is noticeable on the spectrum of the stator currents, which is computed using the FFT. However, for a wind turbine, the spectrum of the currents changes with the wind speed. Therefore, the obtained results may not be accurate. In this paper, the residuals between an Extended Kalman Filter and the measured currents are proposed to be used for fault diagnosis and identification, via the FFT. The spectrum of the residuals is invariant to changes in the wind speed, but sensitive to faults.