A Dual-Resonant Topology-Reconfigurable Inverter for All-Metal Induction Heating

Traditionally, domestic induction heating (IH) is designed to heat the ferromagnetic (FM) pan. However, it is incompetent to heat the non-ferromagnetic (NFM) pan since the small equivalent resistance of the pan will easily result in the overcurrent on the inverter. Inspired by the compensation network in the wireless power transfer (WPT), the series-parallel resonance (SPR) network with a relay switch is newly integrated into the IH technology to develop a dual-resonant topology-reconfigurable inverter for all-metal IH. The proposed system can be purposely configured to a half-bridge series resonant inverter with the pulse width modulation (PWM) to heat the FM pan, or a full-bridge SPR-based inverter with the phase shift control (PSC) to heat the NFM pan, respectively. Moreover, the output-input current gain of the SPR network equals the heating-coil quality factor, thereby readily eliminate the overcurrent issue of the inverter. For exemplification, a 1 kW prototype has been built with system efficiencies of 94.32% and 91.05% for heating FM and NFM pans, respectively. Finally, the proposed system can be evolved to achieve automatic load detection and impedance matching to ensure uninterrupted resonance. Both calculated and measured results are given to validate the flexibility and feasibility of the proposed system.