Development of a 30-kW Class High-Speed Superconducting Generator Prototype With a Novel Hybrid-Excitation Method for Electric Aviation Propulsion

With the development of aviation propulsion toward a hybrid electric propulsion system, a superconducting machine plays an important role with the high power density and high efficiency. In this article, a 30-kW 10 200-r/min superconducting homopolar generator prototype is designed to meet the high speed requirement of electric aviation. And a superconducting hybrid-excitation method based on permanent magnet auxiliary excitation is proposed to alleviate the issue of magnetic saturation in the homopolar rotor. The no-load and load output characteristics of the prototype under electric excitation, permanent magnet excitation, and hybrid excitation are tested experimentally. The results revealed out that the output power of hybrid excitation type is significantly better than the sum of output power of electric excitation type and permanent magnet type. The phenomenon was reasonably explained by analyzing the magnetic flux distribution of different types of rotors through finite-element simulation. The research provides an important design basis for the future design of megawatt high-speed superconducting generators for aviation electric propulsion and green aviation.