Design Procedure and Implementation of Inductor Using Litz Wires for Induction Heating

Induction heating (IH) is applied to convert electricity into thermal energy with a high frequency (HF) current flowing through an inductor. Litz wires help mitigate the power loss at the inductor winding in HF applications by reducing eddy currents. This work presents a detailed approach to designing a power inductor using Litz wires for IH using an inductor-inductor-capacitor (LLC) resonant tank. In comparison to a single solid or stranded wire with the same requirements, the developed formulas in this paper show that the size of the Litz wire inductor is approximately 15% smaller. The step-by-step design procedure is presented with all required formulas and associated information. The feasibility of the proposed design process is illustrated and verified through an experiment on a 2 kW, 100 kHz LLC IH system.