Superconducting AC Machines and Cryogenic Power Electronics for Reliable and Power-Dense Energy Conversion

Implementing superconductivity in rotating electrical machines has many advantages such as increased efficiency, smaller size, and lighter weight if compared to conventional electrical machines. Due to the operative limitation of superconductors, they were mainly used in the DC excitation field windings. However, to target ever higher power density values, there are considerable efforts to use superconductors for the AC windings. This paper reviews the main significant prototypes that implement partially and fully AC synchronous and asynchronous superconducting machines. In the perspective of future cryogenic and superconducting integrated electric drives, the paper also reports research activities on the power electronics components under cryogenic temperature. Moreover, considering the safety critical applications or harsh environments where these drives are expected to be used, recent advancements on diagnostic techniques for electrical machines and drives for cryogenic environments are included.