Surface temperature control of a rotating cylinder heated by moving inductors

Abstract This paper concerns the precise temperature control of a cylindrical object heated by induction using a set of moving inductors. Induction heating by moving inductors in tandem with the rotating movement of the cylinder enables the temperature field to be formed and corrected in any region on the cylinder surface. The temperature control can be effectively supported by appropriately processed images acquired from the infrared camera. Since the movement of inductors over the surface of a cylinder plays a crucial role in temperature control, this paper presents two different algorithms for inductor positioning: a systematic algorithm and a tracking algorithm. In the systematic approach the inductors move periodically along the whole length of the cylinder generatrix while in a tracking one their movement is governed by a detailed analysis of an infrared image of the cylinder. Specific features of both solutions have been analyzed in this paper. Both simulations based on a numerical thermal model of the cylinder and experiments performed during the heating-up phase and during the normal work of a semi-industrial heating system prove the effectiveness of the proposed methods.