A bridgeless BHB ZVS-PWM AC-AC converter for high-frequency induction heating applications and non-smoothed DC-Link characteristics

Performances of a zero voltage soft-switching (ZVS) pulse-width-modulated (PWM) utility frequency ac (UFAC) to high-frequency ac (HFAC) resonant power converter for induction heating (IH) applications are presented in this paper. The series resonant ac-ac converter proposed herein can process the frequency conversion without any diode bridge rectifier (DBR), thereby reducing the relevant conduction power losses. Power factor correction (PFC) can be naturally achieved by the inductor-based boost half-bridge (BHB) circuit with the non-smoothed dc-link. The characteristics of the non-smoothed dc-link stage including PFC and voltage regulations are demonstrated in an experiment with a 3.0kW–30 kHz prototype. Finally, the feasibility of the proposed ac-ac converter is evaluated from a practical point of view.