Modeling and Design Method of Interconnection for Cryogenic Power Electronics Testing Down to 50 K

CCryogenic power electronics have emerged as a critical technology for applications ranging from superconducting systems to deep-space exploration. To ensure reliable low-temperature operation, the thermal and electrical management of the cryogenic apparatus is essential, where the design of conduction leads acts as a governing factor. This paper presents an analytical modeling framework for the temperature profile of cryogenic conduction leads, designed to balance thermal load against electrical voltage drop and power loss. The model is grounded in the linearization of temperature-dependent material properties, augmented by a novel error compensation method. This approach extends predictive accuracy down to 50 K. Furthermore, sensitivity analysis reveals the lead resistance as the metric most susceptible to parameter uncertainties. Experimental validation demonstrates that the model predictions align closely with measurement data, achievingR2consistently above 0.98. Notably, the relative error remains below 3% at 50 K across different operating currents. While numerical benchmarks confirm that thermal radiation induces deviations under high-temperature overload conditions, its impact is negligible within standard cryogenic operating ranges. Finally, based on this validated model, a systematic design methodology is proposed to optimize the conduction lead geometry for both pulse-based characterization and continuous operation, ensuring compliance with strict thermal and electrical constraints.