Thermal Model and Optimization of a Multi-winding Transformer for Lunar Surface Power Transmission

In this paper, a steady-state thermal analysis is conducted for a multi-winding transformer designed for lunar surface power transmission applications. The study employs a lumped parameter network (LPN) method to derive a thermal equivalent circuit dominated by radiation and conduction for performance analysis and design optimization. A Finite Element Method (FEM) model is developed to accurately evaluate the thermal performance of two transformer design iterations under operating conditions of 77 K and vacuum. The FEM model is validated against experimental results conducted in a low-pressure chamber to ensure its reliability. To further demonstrate the design improvements, two transformer prototypes are evaluated using simulation results under cryogenic vacuum conditions and experimental results under low-pressure, room-temperature conditions. The experimental results confirm the improvements over the design iterations, while the FEM analysis highlights significant performance enhancements in the second design.