Modeling and Implementation of Inductive Brushless Exciter for Superconducting Synchronous Machines

Journal article, 2026

Superconducting (SC) machines are increasingly favored for high-power-density applications due to low losses in field windings while generating high magnetic flux. To transfer power to the field winding, brushless exciters are a promising solution as friction is eliminated. However, conventional brushless exciters in SC machines are bulky. A general approach to reduce size is to increase the frequency of power transfer. Nevertheless, the existing high-frequency exciters do not fit SC machines due to the extremely low-voltage and high-current of SC field windings. In this study, the feasibility of applying high-frequency brushless exciters to SC machines is investigated. Firstly, an analytical model is developed to characterize the excitor, including output current and losses. Then, finite-element simulations are performed to assist the design of rotating transformer to reduce AC resistance and branch imbalance. In the end, an exciter is prototyped and tested. The prototype successfully transfers the required amount of current to the load, which proves the feasibility of applying high-frequency brushless exciters to SC machines.