Next generation induction heating: GAN vs. MOSFET based resonant power converter for residential use

Abstract

Flexible-surface induction cooktops require handling various induction heating loads simultaneously, each with different behaviors and power requirements. Multi-output inverter topologies are designed to manage power independently with minimal components and high power density. However, traditional modulation strategies face limitations in ensuring soft switching for reduced losses. Wide band gap devices offer a new approach, where soft switching isn't necessary for high efficiency. To achieve flexibility, domestic induction heating relies on multi-coil structures for optimal temperature distribution. Different coil-pot systems are treated as independent loads, each with specific parameters and power needs. Multi-output topologies, derived from full bridge, half-bridge, and single switch configurations, are developed to tackle the challenge of multi-load power transmission. These topologies balance complexity, versatility, and efficiency based on factors like inductor size, number, target material, and heating distance. A cost-effective and versatile family of multi-output resonant inverters, derived from the half-bridge topology, is described. This work further develops this idea by proposing a high-efficiency implementation of an array multi-output converter with a column structure able to operate under load mismatch achieving reduced power losses, which eases integration into a flexible IH cooktop. Highefficiency multi-output converters are a key enabling technology for the widespread use of flexible surface IH cooktops. Due to the application characteristics, complex modulation strategies appear, requiring an additional effort in the topology design, ensuring reduced power losses regardless of the nature of the switching sequence. However, they suffer from limitations when applying classical modulation strategies to ensure soft switching, which is required to reduce transistor losses and achieve efficient operation. The prototype shows different outputs for induction heating, and in the future, those outputs can be used to develop the IH cooktop.