COMPARISON OF ROTOR FLUX PARAMETERS

Examples include a method for detecting the evolution of the magnetic state of a permanent magnet rotor. The method includes, during a first and a second time interval, applying a respective direct current command signal to the motor to estimate a respective stator resistance value, and applying a respective alternative voltage command signal corresponding to a specific direct axis stator current value to the motor while measuring respective stator phase current values. The method also includes determining respective rotor flux parameters as a function of the measured respective stator phase current values and of the estimated respective stator resistance values. The method further includes comparing the respective rotor flux parameters. The first and second time intervals are separated by a time period which exceeds at least 100 times any one of a first or second interval length.