Study on scaled-down Fuel-Cell DC-DC Converter for Development of Hybrid Power System in Part 23 Class Aircraft

This paper proposes the design and control strategy of a DC-DC converters for fuel cell hybrid power system(FCHPS), intended for application in a 1.8 MW-class, 19-seat short take-off and landing (STOL) commuter aircraft. To facilitate development and validation, the total power system is scaled down to 10 kW, comprising four 2.5 kW-class fuel cell modules and two 5 kW-class DC-DC converters. The proposed fuel cell hybrid power system is configured to simultaneously support inverter power supply and battery charging using power generated from hydrogen fuel cells. Each converter receives input from two fuel cell power stack modules and distributes its output through two separate channels: one for inverter operation and the other for battery charging. To implement this functionality, a hydrogen fuel cell DC-DC converter was designed using four buck converter circuits arranged into two sets, enabling two distinct output modes. A voltage control algorithm incorporating a dual-loop current controller for current balancing, along with a power distribution algorithm for mode switching, is introduced to drive the converter effectively. The performance of the proposed converter was validated through MATLAB/Simulink-based simulations and experiments using an actual hydrogen fuel cell system, confirming its applicability to hybrid power systems for aviation use.