A 200-kHz/1.5-kW Multi-winding Transformer for Lunar Surface Power Applications

This paper introduces the design and development of a high-frequency (HF) multi-winding (MW) transformer intended for modular-multilevel-converter (MMC) based isolated dc-dc converters for lunar surface applications. The transformer features a flexible multi-winding design, allowing for varying turns ratios, which enhances the versatility and interchangeability between two isolated dc-dc converters and simplifies the system. The designated leakage inductance achieved with stereolithography (SLA) 3D printed bobbin also improves the power density of the converter. The design methodology, core material selection, multi-winding design considerations, power loss calculations, and Finite Element Analysis (FEA)-based thermal simulations are performed. The transformer core characteristic is evaluated in a cryogenic vacuum chamber. The transformer performance is validated within a 1.5-kV, 1.5-kW, 200-kHz isolated multilevel dc-dc converter.