Application of GaN device to MHz operating grid-tied inverter using discontinuous current mode for compact and efficient power conversion

This paper studies on a grid-connecting inverter using a gallium nitride (GaN) device aiming for passive components size reduction by very high switching frequency operation. This paper proposes to apply a discontinuous current mode (DCM), which does not require dead-time and current feedback control, which are usually required for a continuous current mode (CCM) operation. These features enable a good modulation performance with a MHz-class high switching frequency operation without difficulties coming from the very high switching frequency. This paper reports experimental demonstrations of the DCM grid-connecting inverter using GaN- high electron mobility transistors (GaN-HEMT) with 1 MHz carrier frequency, and discusses output current harmonics and losses.