T36.5 - Reversed-Winding Passive Coil for Simplified Flexible Induction Heating Zones

Over the past decades, induction cooktops have continuously evolved toward flexible heating areas to improve the cooking experience. To achieve this, various systems have emerged in the market, including some that feature several concentric circular windings activated or deactivated based on the vessel's diameter. These solutions require a dedicated power inverter for each inductor, which can lead to significant cost increases. Recently, cost-effective passive inductor designs with secondary resonant capacitors have been developed to provide solutions powered by a single inverter to feed the active winding. Based on this solution, this paper aims to propose an improved flexible-diameter heating area that combines inductive power transfer and induction heating principles. The proposed inductor design results in a secondary configuration without resonant capacitors, simplifying the system and enhancing performance. The configuration is analyzed electromagnetically using finite-element methods, main design considerations are discussed, and experimental prototypes are implemented to validate the proposal.