Multi-resonant Inverter Realizing Downsizing and Loss Reduction for All-metallic IH Cooktop

Induction heating (IH) cooktops require no flame, and are popular with consumers. They have a drawback, though, in that the volume of the circuit becomes very bulky if modified to carry the high currents required to heat cooking utensils made of aluminum, copper, and other non-magnetic metals. This paper discusses the application of a multi-resonant inverter that achieves a small, low-loss IH cooktop suitable for heating non-magnetic cookware. Applying this multi-resonant inverter to the IH cooktop allows losses in power semiconductors to be reduced by 69% when heating an aluminum pot and by 13% for an iron pot, and also allows a 27% reduction in the size of the conventional heating coil and a 36% cut in the size of the high-frequency inverter. This paper also describes the successful development of an input power control for application to an IH cooktop of this type.