A Load-Power Adaptive Dual Pulse Modulated Current Phasor-Controlled ZVS High-Frequency Resonant Inverter for Induction Heating Applications

A new prototype of an efficiency-improved zero voltage soft-switching (ZVS) high-frequency resonant (HF-R) inverter for induction heating (IH) applications is presented in this paper. By adopting the dual pulse modulation mode (DPMM) that incorporates a submode power regulation scheme such as pulse density modulation, pulse frequency modulation, and asymmetrical pulse width modulation into main one of the resonant current phase angle difference ( θ) control, the IH load power can be widely regulated under the condition of ZVS, while significantly improving the efficiency in the low output power setting. The essential performances on the output power regulations and ZVS operations with the DPMM schemes are demonstrated in an experiment based on a 1 kW-60 kHz laboratory prototype of the ZVS HF-R inverter. The validity of each DPMM scheme is originally compared and evaluated from a practical point of view.