Laminated iron core losses variation with frequency and under SPWM excitation

The paper presents a methodology for determination of harmonic iron losses in laminated iron cores under sinusoidal excitation for various frequencies and sinusoidal pulse width modulated voltage excitations. The method is based on measurements performed by using a convenient Epstein device supplied by a sinusoidal and a SPWM source, which are stored and processed in a PC by using an appropriate data acquisition card. It is shown that calculation of iron losses due harmonics cannot be performed by applying summation of harmonic components.