Design Optimization for Enhancing the Power Density and Efficiency for GaN-Based DC–DC Converter

This article presents an optimization strategy for enhancing the efficiency and power density of a GaN-based dc–dc converter, tailored for different applications with a wide input voltage range regulation. The optimization employs air-core inductors and implements a variable switching frequency modulation method to enable zero voltage switching turn-on for GaN transistors, facilitating greater flexibility in frequency adjustment and improved thermal management. Additionally, a specialized thermal model is introduced for the interleaved Buck-Boost GaN transistor-based dc–dc converter, accounting for the presence of a natural convection heatsink. In the conclusion, theoretical discussions transition to practical implementation through the testing of a laboratory prototype. This prototype achieves high efficiency (around 99%), along with power densities of >17.5 kW/L and 6 kW/kg when equipped with a natural convection (without airflow) heatsink. It features a wide input voltage range (110<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">–</i>450 V), a constant output voltage of 350 V, variable switching frequency (18<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">–</i>304 kHz) and supports up to 9 kW output power.