Research on High-Performance Multiphase DC-DC Converter Applied to Distributed Electric Propulsion Aircraft

The performance of the power converter of electric propulsion aircraft (EPA), which should have high efficiency, high power density, and high reliability, affects the volume, weight, and efficiency of the whole electric aircraft (EA). This article proposes a novel dc-dc converter with gallium nitride (GaN) transistors. First, the working modes and main operation waveforms of the converter are analyzed. The new converter can achieve zero-voltage switching (ZVS) and zero-current switching (ZCS) through auxiliary soft switch branches. Compared with the traditional buck-boost converter, the soft switching capability of the proposed converter allows operation at a very high frequency and has higher efficiency. The multiphase interleaving magnetic integration technology is adopted to realize the modular design, which not only meets the requirements of high power and low ripple but also eliminates right half-plane zero in the boost mode, achieves high dynamic response, and improves the power density. A novel parallel multiphase inverse coupled inductor (ICI) and a symmetrical array ICI are proposed to allow a high-density and high-efficiency bidirectional dc-dc converter design for the hybrid energy storage system (HESS) of EPA. Finally, the proposed ICI prototype was compared with the state-of-the-art commercial ICI product, and the comprehensive performance of the converter was verified through steady-state, transient, efficiency, and thermal experiments.