Magnetic properties of 6.5% silicon steel sheets under PWM voltage excitation

Abstract

Power losses of 6.5% silicon steel sheets under PWM (Pulse Width Modulation) voltage excitation were examined. The PWM wave was composed of a 50Hz fundamental wave, a 16kHz carrier frequency wave and some other higher harmonics. It was found that the power losses of the inductor cores were much larger than those of the transformer cores when the cores were driven by a PWM inverter, although such a great difference was not observed under sinusoidal voltage excitation. Power losses of the inductor made of 6.5% silicon steel sheets and conventional grain oriented 3% silicon steel sheets under PWM voltage excitation were also investigated It was found that the power losses of the inductor made of 6.5% silicon steel sheets were reduced by more than 30% compared to those of the inductor made of grain oriented 3% silicon steel sheets. This was because the grain oriented 3% silicon steel sheets had higher losses at higher harmonics found in the PWM excitation. Therefore, it was clearly shown that 6.5% silicon steel sheet was a suitable material for the inductor under PWM voltage excitation.

Recent development of non-oriented electrical steel sheet for automobile electrical devices

“…Fig. 9 shows the flux density dependency of audible noise in high-frequency test reactors [7]. The thickness of the 6.5% Si steel and grain-oriented electrical steel is 0.1 mm and the Fe-based amorphous alloy is 0.025 mm.…”