Multi-MOSFET-Based Series Resonant Inverter for Improved Efficiency and Power Density Induction Heating Applications

Resonant converters featuring soft switching are commonly used in domestic induction heating applications due to their high efficiency and high power density. In this paper, the design and implementation procedure of an improved efficiency and low-profile resonant inverter for induction heating applications is presented. The proposed converter is based on a multi-MOSFET cell implementation, reducing the equivalent on-state resistance per chip-area. By using automotive-grade MOSFET devices, a converter capable of delivering up to 4 kW has been built, reducing conduction losses against the classical IGBT-based converter. In addition to this, the reduced switching times of MOSFET devices decrease switching losses, further increasing the conversion efficiency. The main design challenges including the device selection, gate drive circuit, and cooling have been addressed. As a conclusion, a low-profile implementation without fan and heat sink is obtained, which significantly improves state-of-the-art technology in terms of efficiency and power density.