Modeling and Analysis of Transient Performance for Induction Heating System Considering Frequency-Dependent Inductive Load

In this paper, the modeling process and transient performance analysis for induction heating system (IHS) are carried out, considering the frequency-dependent inductive load. First, the impedance of the inductive load at the frequency range of interest is computed by using the finite element method (FEM). Then the vector fitting (VF) and the passivity enforcement techniques are employed to obtain a stable, causal, and port passive rational approximation model for the considered impedance. Afterward, the circuit synthesis method is used to achieve a circuit representation in terms of the pole-residue rational model. Good agreements between the presented equivalent circuit and the results of the FEM are achieved both on the magnitude and on the phase. Finally, the transient performances of the IHS under the controls of open-loop and closed-loop are conducted. This transient model with the inclusion of frequency-dependent inductive load provides a reliable prediction method of energy efficiency at the early stages of design.