Development and testing of a 1 G based high temperature superconducting (HTS) double pancake coil for HTS synchronous machines

Abstract

High Temperature Superconducting (HTS) synchronous machines are highly efficient, compact, lighter, low noise, high output power to weight ratio and better dynamic response machines compared to conventional copper conductor based machines. HTS synchronous machines are used worldwide for various strategic and critical industrial applications, because of the above mentioned advantages. Successful development of HTS synchronous machine requires HTS, electrical, mechanical, cryogenic and vacuum technologies. The major components of a HTS rotor and copper winding stator topology synchronous machine are air gap copper winding stator, HTS rotor, excitation system, cryogenic cooling and vacuum systems. HTS rotor consists of HTS tape wound pole coils, which generate DC magnetic field when DC current passes through them. There will be no joule heat in the HTS pole coils due to superconductivity. Each pole coil consists of few numbers of field coils (in the form of double pancake coils) which are stacked to form a pole. One of the main technical challenges for manufacturing HTS rotor is development of HTS field coil. The development of a HTS field coil involves the selection of HTS tape, winding technique, handling of the HTS tapes while winding and testing of the HTS coil at cryogenic temperatures of 77 K and 35 K. In the present work, a HTS racetrack double pancake coil using 1 G HTS tapes was fabricated and tested. The details of design, development and cryogenic testing of 1 G HTS tapes wound double pancake coil are presented in this paper.