Control Strategy of Resonant Load Identification for Free Zone Induction Heating Systems with WBG-based Multiple Inverters

Domestic induction cooktops can only be heated in the designated circular cooking zone. Therefore, this paper proposes a control strategy and implementation of the free zone induction cooktop (FZIC) system that can freely heat multiple pots regardless of size and location over the entire area of the induction cooktop. The FZIC system is implemented by applying wide-bandgap (WBG) power semiconductors to improve power density and efficiency. A control strategy using the power curve fitting method (CFM) is presented to quickly detect parameter changes in multi-resonant loads. In addition, a control algorithm is established to enable immediate reheating by identifying the location information of the pot in real time when the pot moves during heating. To evaluate the performance of the control algorithm strategy of the proposed FZIC system, the results of IH experiments based on the 3.2kW FZIC prototype are presented.