Analysis and control of the heat distribution in a zone-control induction heating system

This paper deals with analysis and control of the heat distribution in zone-control induction heating (ZCIH) systems. A ZCIH system consists of two or more split working coils and inverter units, which enables to control the heat and/or temperature distribution on the workpiece by adjusting the current amplitude through each working coil. This paper carries out the theoretical analysis of the generated heat in the workpiece, and reveals a relation between the coil currents and the heat distribution. As a results, it is also clarified that the heat distribution can be estimated by a simple calculation using a three-dimensional resistance matrix. The experimental results are shown to verify the validity of the developed theory by using a six-zone ZCIH laboratory setup.