Analysis and Conceptualization of a 400 V 100 kVA Full-GaN Double Bridge Inverter for Next-Generation Electric Vehicle Drives

The rising demand for electric vehicles (EVs) is pushing the industry to develop cheaper, lighter and more efficient powertrains. In particular, the drive inverter represents a crucial component of an EV drive train, being responsible for the DC/AC power conversion between the battery and the electrical machine. As a result, advanced converter topologies and modern wide bandgap (WBG) semiconductor devices are being actively evaluated by both industry and academia, aiming to improve the performance of next-generation EV drive inverters. In this context, the double bridge inverter (DBI) represents a promising candidate for 400 V EV powertrains, allowing to increase the machine phase voltage and thus to reduce the inverter phase current for a given power level. Although a three-phase machine with an open-end winding configuration is required, the DBI unlocks significant benefits at the converter level, especially if state-of-the-art 600/650 V GaN high electron mobility transistors (HEMTs) are employed. Therefore, this paper proposes the analysis and the conceptualization of a full-GaN 100 kVA 400 V DBI for next-generation EV drives. A complete theoretical assessment of the system active and passive component stresses (i.e., semiconductor losses, machine phase flux ripple, DC-link capacitor RMS current and charge ripple) is performed, providing the basis for the converter sizing. Additionally, a DBI design concept is developed, achieving an estimated 99.7% peak semiconductor efficiency (99.2% at rated current) and a 192 kVA/dm3 power density.