Fast method for the iron losses prediction in inverter fed induction motors

In this paper an easy method for the iron loss prediction in PWM inverter fed induction motors is presented. The method was initially proposed and validated for the prediction of the iron losses in non-oriented soft magnetic material with PWM supply. Starting from the iron losses measured with sinusoidal supply and the PWM waveform characteristics, a fast and reliable prediction of the iron losses in the motor can be obtained too. The method requires the separation of the iron losses in the hysteresis and eddy current components with sinusoidal supply, plus the average rectified and RMS values of the applied PWM voltage. The proposed method has been proved on an induction motor prototype able to provide a good accuracy in the iron losses measurement. The comparison between the measured and predicted iron losses with PWM supply have shown an excellent agreement with an error lower then the 5%, confirming the method validity.