GaN-HEMT-based three level T-type NPC inverter using reverse-conducting mode in rectifying

Abstract

The paper presents a design method of a gallium-nitride high-electron-mobility-transistor (GaN-HEMT) based three level T-type neutral-point-clamped (NPC) inverter using a reverse-conducting mode of the GaN-HEMT. The GaN-HEMT provides high-frequency switching speed and the T-type inverter supports such switching by decreasing conduction loss and heat dissipation. The GaN-HEMT has two operation mode, an enhancement mode and the reverse-conducting mode. In the enhancement mode, resistance on the GaN-HEMT is controlled by gate-source voltage. The reverse-conducting mode appears when gate-source voltage is less than zero. This characteristic provides advantage on design of the T-type NPC inverter. Then, the paper shows that a normally-off inverter is easily attained by using the reverse-conducting mode. Verification of the designed-circuit is conducted by some validation.