Reducing Mission Cryogenic Load via HTS Dynamo

Abstract

Electric motors based on conventional conductive materials such as copper and aluminium are limited in efficiency and power density by the resistive losses of these materials. Lighter and more efficient motors are possible when High Temperature Superconductor (HTS) materials are used as there are no resistive losses. Additionally, the high current density that may be supported by these materials enables alternative motor designs which leverage high magnetic fields to remove the requirement for iron components and reduce the overall motor volume. Despite HTS materials exhibiting superconductivity at much higher temperatures than other superconductive materials, cryogenic cooling to below 90 K is still required. Suitable cryocoolers typically have efficiencies below 20%. This unfavorably alters both the specific power and efficiency of HTS based motors when considering the motor as including all the associated hardware required for operation. Previously it has been shown that energizing the superconducting components of a motor wirelessly using a HTS dynamo can reduce the required mass of both the cryogenic refrigeration equipment, and the motor drive electronics. The work presented here investigates the reduction in total fuel burn of a 737 sized turboelectric aircraft that may be achieved when replacing a conventional DC power supply for the HTS motor field coils with a HTS Dynamo DC power supply.