A 3-Phase T-type 3-Level Inverter using GaN Bidirectional Switch with Very Low On-State Resistance

A 3-phase T-type 3-level inverter using a GaN bidirectional switch with very low on-state resistance is presented for the first time. The GaN bidirectional switch is realized by only 1 transistor with dual-gate structure instead of a conventional bidirectional switch which consists of 2 IGBTs and 2 fast recovery diodes with on-state voltage offset. Moreover, the on-state resistance of the GaN bidirectional switch is reduced from 42mOmega to 26mOmega by utilizing reduction of parasitic resistance in a device package. The fabricated 3-phase T-type 3-level inverter using the GaN bidirectional switch exhibits higher peak conversion efficiency 98.7% and 21% reduction of the conversion loss at the output power of 4kW compared to that using the conventional Si-IGBT-based bidirectional switch.