Completely Superconducting Electric Machine with High Specific Power

Abstract

The main tendency in transport development is a move toward electric or hybrid propulsion, which is due to the increased requirements relating to the ecological effects and efficiency of transport systems. A key parameter that determines the prospects of electric transport is the specific power of electric machines (generators and motors). Thus, e.g., electric machines with a specific power higher than 20 kW/kg are necessary to produce electrical aircraft. Studies have shown that, during long operation, such magnitudes of specific power can be achieved with the use of cryogenic cooling and modern high-temperature superconductors (HTSCs) in electric motors and generators. In addition, the critical properties of superconductors should be taken into account, which leads to scientific and engineering problems. In particular, the HTSC stator winding should be made of coils in the form of racetracks. This can be done in a machine with a number of grooves per pole and a phase less than unity. In this work, the circuit of such completely superconducting electric machine with high specific power has been considered. The analytical technique of calculations of the main parameters has been suggested. The obtained expressions allow one to analyze the influence of number of pole pairs, superconductor properties, and main dimensions of a machine on the specific power. The results of the finite-element modeling of a completely superconducting electric machine have been considered.