Design of a 10 kW GaN-based high power density three-phase inverter

The medium power rating two-level three phase voltage source inverter is among the most popular power conversion systems. The typical switching frequency of the commercial medium power rating inverter, however, is limited to tens of kHz. By increasing the switching frequency and using emerging gallium-nitride devices, the size of the overall system can be greatly reduced. This paper begins by reviewing all commercially available GaN power transistors and their package technologies. The GS66516T device from GaN Systems is selected due to its suitable ratings and superior package performance. Then, a half-bridge structure is designed for this device to achieve low parasitic inductance and strong cooling capability at the same time. The dynamic characterization results of this 650V/60A Enhancement-mode GaN transistor are extracted with the proposed half-bridge structure. A gate drive circuit with comprehensive protection function is integrated. Based on the proposed phase-leg structure, a 10 kW three phase inverter prototype is built and the experimental waveform is shown at the end.