Influence of Thickness of Non-oriented Electrical Steel on Iron loss under Inverter Excitation

Abstract

This paper shows that the influence of thickness of non-oriented electrical steels on the iron loss under PWM inverter excitation. It is already known that the iron loss under PWM inverter excitation is higher than the iron loss under sinusoidal excitation. We evaluated the iron loss of non-oriented electrical steels having various thicknesses under PWM inverter excitation in comparison to a sinusoidal excitation. The difference of the iron loss between inverter excitation and sinusoidal excitation is increased with the increase in material thicknesses. This tendency became marked in low carrier frequencies and low modulation factors. From the FFT analysis on flux waveforms, it was found that the high-harmonic component amplitudes in flux waveforms were increased with decreasing carrier frequencies and modulation factors, which resulted in the increase in eddy current losses, especially in thicker electrical steels.