Iron Loss Characteristics of Motors Fed by Fast Switching GaN-FET Inverters

Iron losses generated in a motor made of non-oriented electrical steel and driven by an inverter consisting of fast switching power semiconductor devices, GaN-FETs were studied. The rectangular voltage pulses from the pulse width modulation applied to the motor generate not only a fundamental current but also harmonic currents. One of them increases considerably at the resonant frequency of the L, R, and C components in the motor. The phenomenon is called ringing. The ringing current, as well as the other currents, result in their respective iron losses. This study experimentally confirms that ringing occurs in the motor and quantitatively evaluates the iron loss related to it. The proportional dependence of the loss on the carrier frequency of PWM is found out.