A new dual mode current phasor-controlled ZVS high-frequency resonant inverter for induction heating

A novel soft-switching high-frequency (HF) resonant (HF-R) inverter for induction heating (IH) applications is presented in this paper. By adopting the phase shift (PS)-based current phasor (CP)-controlled, the IH load resonant current can be continuously regulated under the wide-range soft-switching conditions. In order to improve the conversion efficiency in the light load region, the pulse-density-modulation (PDM) is employed for the CP-controlled HF-R inverter, thus creating PS& PDM dual mode CP-control scheme. The essential performances on the output power regulation and soft-switching operations are demonstrated in experiments using a 1 kW-60 kHz prototype, and then its topological validity is evaluated from the practical point of view.