Experimental Verification and Loss Analysis of MHz-operating Discontinuous Current-mode Grid-tied Inverter using GaN-HEMT Device

Abstract

This paper studies a grid-tied inverter using a gallium nitride (GaN) device aiming for passive component size reduction through 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 that are usually required for a continuous current mode (CCM) operation. These features enable good modulation performance with a MHz-class high-switching-frequency operation without difficulties owing to the very high switching frequency. This paper reports experimental demonstrations of the DCM grid-tied inverter using GaN- high-electron-mobility transistors (GaN-HEMT) with 1-MHz carrier frequency and three different filter components. Output current harmonics and losses are discussed, and it is indicated that chip inductors are promising for DCM-operated low-power inverters.