Experimental verification of 1 MHz PWM inverter for generating high frequency sinusoidal current

Recently, kHz-class frequency components with several kW power are widely used in industry applications and home appliances. Wireless power transmission system and induction heating demand for over 20 kHz sinusoidal current waveforms. Furthermore, higher-switching frequency inverter are discussed for realizing high-power density circuit and reducing passive components, EMI filter and switching ripple filter size. PWM inverter is proposed because it does not require capacitors, and easy to control the output current. If the PWM inverter is applied to those applications, the switching frequency should be set to 500 kHz or higher. For realizing high switching frequency PWM inverter, dead-time and inverter efficiency are the key parameters. The sum of dead-time and rise or fall time has to be smaller than the voltage pulse at peak value. And the inverter efficiency must be high to reduce the power loss and decrease the junction temperature of power device. This paper presents a PWM inverter operated at 1 MHz switching frequency, which utilized Si-MOSFET and GaN power device. With utilization of GaN power device, the PWM inverter can operate with higher efficiency at several MHz switching frequency.