GaN FET単相PWMインバータによる高キャリア周波数励磁時の鉄損特性

Abstract

The Iron loss at higher carrier frequencies up to 190kHz is measured by a single-phase GaN FET inverter because sinusoidal-like waveform is expected to be obtained by new material devices such as those based on SiC or GaN. The measured data show that iron loss excited by PWM inverter does not converge to the iron loss by sinusoidal excitation because the fluctuation in the magnetic field does not converge to zero, even when carrier frequency is 190kHz. Moreover, the iron loss even increases at some carrier frequency for a long dead time. Because of the properties of the GaN FET device, the ON voltage of the GaN FET during the dead time period becomes large, and the minor loop shape in the magnetic hysteresis curve becomes large. These phenomena are observed for a constant applied DC voltage and also for a constant modulation factor constant condition. The properties of the power semiconductor and the dead time of the inverter seriously influence the increase in the iron loss.