METHOD AND DEVICE FOR DETECTING THE PRESENCE OF A PERMANENT MAGNET OF A ROTOR OF A SYNCHRONOUS MACHINE

The present disclosure relates to a method of detecting the presence of a permanent magnet of a rotor of a synchronous machine, wherein the method comprises: providing (S2) an injection of a voltage waveform to the stator windings of the synchronous machine, obtaining (S3) a measurement of two phase currents in the stator winding generated due to the injection of the voltage waveform, transforming (S4) the two phase currents to a rotor reference frame to obtain a current waveform in the rotor reference frame, sampling (S5) the positive portion of a cycle of the current waveform to obtain sampled positive portion values and the negative portion of a cycle of the current waveform to obtain sampled negative portion values, constructing (S6) a first periodic waveform by using the sampled positive portion values and a second periodic waveform by using the sampled negative portion values, performing (S7) a frequency analysis of a first spectrum of the first periodic waveform and of a second spectrum of the second periodic waveform, and determining (S8) whether a permanent magnet is present in the synchronous machine based on the first spectrum and on the second spectrum.