Research on the Conduction-Cooled YBCO Magnet for an MW Class Induction Heating System

High-efficiency high-temperature superconducting (HTS) induction heating equipment has been regarded as a promising application for thermal processing of metal material, in which an HTS magnet generates a high magnetic field to form the background field in the iron core and the rotating billet is heated by eddy current to process temperature. Efficiency analysis for the traditional induction heating and new structures for the HTS induction heating are studied in this paper. A new type of superconducting induction heating magnet structure is proposed. Through the parallel connection of multiple magnetic circuits, it can make more effective use of the high magnetic field produced by superconducting magnets. The applicable range and application criterion of the new structure are also given. Calculation models for induction heating system electromagnetic field and billet region temperature field analysis are established. The megawatt (MW) class conduction-cooled Yttrium Barium Copper Oxide (YBCO) magnet system is designed. The magnet consists of an iron core and HTS coils wound with the spliced YBCO-coated conductors. The magnet system is cooled by two AL325 GM refrigerators and the operating temperature is 20 ∼ 30 K. Furthermore, the prototype YBCO coils with the same thickness are fabricated and tested in the LN2. Test result of the prototype magnet is presented.