Energy conservation and emission reduction is a critical task for China’s aluminum industry. Different from the present AC induction heater, HTS direct current (DC) induction heater is expected to significantly improve the energy efficiency of preheating aluminium billets before extrusion process. The world’s first commercial megawatt HTS DC inducting heater based on 2nd generation HTS tapes has been developed and put into operation. In this paper, the commercial design of this 1 MW HTS DC induction heater including design specifications, energy efficiency and commercial potential are presented and analyzed thoroughly. Subsequently, the manufacture and operation of three core parts including HTS magnet with extra-large diameter, iron core structure and electrical driving system, are introduced. The excitation current of 130 A to the magnets coupled with iron core can generate a magnetic flux density larger than 0.45 T at the center of the air gaps. Test results showed that the HTS DC induction heater has much higher energy efficiency (80 - 90%) than its AC counterpart (40 - 50%). Over years of operation and testing on this machine have validated the practicability and reliability of megawatt HTS DC induction heater concept.

Fig.1 Structure of the HTS DC induction heater.

Keywords: Induction heater, Superconducting magnet, YBCO