All-Metal Domestic Induction Heating Using Single-Frequency Double-Layer Coils

This paper proposes and implements a single-frequency double-layer coil system for all-metal domestic induction heating. Traditional induction heating has been developed to effectively heat a ferromagnetic pan, but is incapable of heating a non-ferromagnetic pan as it will cause high current stress at the power source. Inevitably, this limitation has hampered the popularization of existing induction heating. The proposed system consists of double-layer concentric coils with their compensated capacitors connected in series. The key is to employ the magnetic resonant coupling mechanism to strengthen the magnetic coupling and hence to enhance the power transfer between the coil and the pan. Differing from using a higher frequency to separately heat the non-ferromagnetic pan, the proposed system can employ a single frequency to operate at the high-voltage low-current and low-voltage high-current modes to effectively heat the ferromagnetic and non-ferromagnetic pans, respectively. Moreover, the required high current can be shifted from the primary coil to the resonant coil, hence significantly reducing the current stress at the power source. Both simulation and experimental results are given to validate the feasibility of the proposed induction heating.