A Bridgeless BHB ZVS-PWM AC–AC Converter for High-Frequency Induction Heating Applications

A new prototype of a zero voltage soft-switching (ZVS) utility frequency ac to high-frequency ac resonant power converter for induction heating (IH) applications is presented in this paper. The series resonant ac-ac converter proposed herein can process the frequency conversion without any diode bridge rectifier, thereby reducing the relevant conduction power losses. In addition, power factor correction (PFC) can be naturally achieved by the inductor-based boost half-bridge circuit with the nonsmoothed dc-link. The operation principle together with an IH load power regulation scheme is described, and the converter performances including ZVS operations and PFC are demonstrated in an experiment with a 3.0-kW-30-kHz prototype by comparing it with the previously developed converter. Finally, the feasibility of the proposed ac-ac converter is evaluated from a practical point of view.