High Power-Density Design Based on WBG GaN Devices for Three-Phase Motor Drives

The use of Wide Bandgap (WBG) semiconductor devices in power conversion systems is continuously increasing due to their superior performance over Silicon-based devices, enabling enhanced efficiency and power density in power converters. This paper presents a compact inverter based on GaN power devices. It has been compared with other ST solutions utilizing Silicon (Si) power devices, considering both free air and forced ventilation conditions for heat dissipation. The integration of a half-bridge in a single Integrated Circuit (IC), parallel DC-link filtering, high PWM switching frequency, and compact auxiliary power supplies contribute to an increased power density of the proposed solution. The first minimizes the area required for driving and power circuits, while the second and third reduce the size of filtering components due to decreased DC voltage ripple at higher frequencies. The aforementioned design specifications ensure the solution is space-efficient. System simulations aimed at optimizing the inverter's performance are presented. A 300W three-phase inverter prototype has been constructed, and the key parameters, experimental results, and benchmarks are discussed. The computed power densities are 59.6W/cm
³
under forced ventilation and 33W/cm
³
in free air conditions, achieving peak efficiencies of 96.4% and 97.2%, respectively. The benchmark results demonstrate that the proposed solution surpasses Si-based solutions in terms of power density. Overall, this article provides valuable insights into the design and development of compact inverter boards based on GaN devices, offering utility for researchers and engineers in the field.