A Review of the State-of-the-Art Superconductor Technology for High Power Applications

The all-electric or hybrid electric aircraft concepts promise to open up a new revolution in aviation design. However, with this paradigm shift comes problems in the use of existing materials. For example, normal conductors such as Cu or Al exhibit waste heat with a geometric dependence on current (Q=I2 R) which, for higher power (current) applications necessitates that costly and heavy cooling apparatus be installed. The sheer volume of conductor needed for high power applications also serves to increase weight. In this paper we advocate for the use of superconducting materials to serve the aerospace industry's need for high power electric aircraft as they can carry exponentially more current in the superconducting state than normal conductors, thus reducing weight and volume. The weight and size of any cooling apparatus associated with superconductivity will thus be much reduced in size as well. In rotating machines (i.e. motors and generators) superconductors have the added benefit of being able to sustain much higher magnetic fields than conventional materials, thus enabling higher efficiencies. In this paper we will first detail the advantages of superconductors for use in aircraft platforms and then proceed with brief summaries of the current state-of-the-art for the most advanced (in terms of R&D effort) superconducting systems. We will conclude with a brief summary in machine technology where we will address the problem of AC Losses.