A Constant Power Regulation with Two Series Resonant Inverters for Metal Induction Heating Systems

The paper explores an induction heating system powered by a multiphase source and utilizing two series resonant inverters. These inverters supply mutually coupled working coils to ensure uniform temperature profiles and segment power inverters for metal tempering tasks. This study introduces a control strategy focused on maintaining constant input power, emphasizing the benefits of the two-phase system through an equivalent circuit model. It demonstrates that by continuously adjusting the current and phase shift between the supply units, coupling effects are reduced, allowing the system to achieve better performance. Both open and closed loop power control using a PI regulator on the DC converter are evaluated, with two case studies examining temperature-dependent load parameters. Simulations and experimental results validate the method’s effectiveness