First harmonic equivalent impedance of coupled inductive loads for induction heating applications

Switched-mode power supplies applied to induction heating provide conditioned power to a wide range of loads. One of the main issues in the design of these systems is the identification of the main characteristics of the load, i.e. electrical equivalent, as it to be modeled by means of a reduced set of variables. This paper proposes the procedure to extract the electrical equivalent model of the inductor system composed of a coupled double concentric coil for induction heating purposes. The parameters have been obtained by means of a method based on the Fourier analysis of experimental measurement under adequate operation conditions. The equivalent model has been validated for different working conditions in order to prove the feasibility of the proposed procedure.