Enhanced load adaptive modulation of induction heating series resonant inverters to heat various-material vessels.

Nowadays all-metal induction heating (IH) cooktops have become popular for heating various pots quickly and safely. A load adaptive modulation (LAM) method was proposed to improve the IH power delivery capability and the cost-effectiveness of an all-metal IH system. However, this method shows poor power conversion efficiency under light-load conditions since a high switching loss is induced using the pulse frequency modulation (PFM) method in the series resonant inverters for IH applications. In this paper, a multi-mode control strategy for an IH system employing the LAM method is proposed to improve light-load efficiency when compared with the conventional LAM method. The proposed multi-mode control algorithm automatically changes its modulation according to the pots' material-dependent resistance. The modulation method is selected to improve the light-load efficiency using the proposed control strategy. Experimental results demonstrate the validity and performance of the proposed multi-mode control algorithm with a 2-kW prototype IH series resonant inverter and various-material pots. [ABSTRACT FROM AUTHOR]