T33.1 - High Power Density Three-Phase LLC DC/DC Converter with Coupled Resonant Inductor and Wye-Delta Transformer for Aircraft Applications

In this paper, a DC/DC converter is designed, validated and built to fulfil the strict demands of aircraft applications. A wide input voltage (200 to 330 V) high frequency (1 MHz) and high power density converter (20 kW/L) is presented. As the nominal output is 28 V, a high voltage step-down is required for which a three-phase LLC was proposed to take advantage of three-phase transformers, particularly, the wye-delta configuration, minimizing the number of turns of the primary enabling the use of PCB windings. A novel technique is proposed in which the resonant inductors are merged into a three-phase inductor.