Numerical Electromagnetic Analysis for Metal Ring Induction Heater

Numerical electromagnetic analyses for metal ring induction heater are conducted by FEM. The magnetic flux density along the iron core and the eddy current distribution as the heat source are investigated. It is found that the magnetic flux density along the iron core is not to uniform. The value has the maximum around the heating coils, and besides as the distance from the heating coils increases, the magnetic flux density value decreases to the lowest at the I-shape core where the metal ring to be heated is located. With the knowledge of the magnetic flux density along the core obtained, the eddy current densities within the metal rings are obtained by FEM and a theoretical approach. The theoretical results agree well with the FEM results. The values and the theoretical formula can become a necessary piece of information when developing the advanced control of the metal ring induction heater.