GaN HEMT for Electric Car Inverter: Breakthroughs and Challenges

March , 2023

Abstract:

The mobility industry has been living through the most dramatic changes since the invention of the internal combustion engine and the standardization of the manufacturing process. Society and governments are looking for zero-emission transport, while car makers seek the most efficient way to manufacture low-cost, long-distance electric cars. In this context, inverter efficiency became the critical performance parameter, and semiconductors with low loss switching energy, such as SiC and GaN, are getting into the spotlight.

This keynote discusses the successful development and results of a three-phase GaN-based inverter reference design with 400V bus voltage and 400A RMS current. The significant steps from semiconductor chip design through module development and full current inverter operation will be discussed, chosen solutions explained, and results will be presented. The main challenges include robust high current > 100A GaN die, with low parametric shift because of repetitive unclamped switching tests up to 1600V; driving 4 dies in parallel to obtain equal current sharing, the smooth waveform at needed current, and obtaining low voltage overshoots on the gate and the drain.