Commercial Frequency AC to High Frequency AC Converter With Boost-Active Clamp Bridge Single Stage ZVS-PWM Inverter

This paper presents a novel soft-switching pulsewidth modulation (PWM) utility frequency ac to high frequency (HF) ac power conversion circuit incorporating boost-active clamp single stage inverter topology. This power converter is more suitable and acceptable for cost effective HF consumer induction heating applications. Its operating principle is presented using the switching mode equivalent circuits in addition to the operating voltage and current waveforms. The operating performances of this high frequency inverter using the latest insulated gate bipolar transistors are illustrated, which includes HFAC power regulation ranges and actual efficiency characteristics based on zero voltage soft switching operation ranges and the power dissipation loss analysis as compared with those of the previously developed high frequency inverter. In addition, a dual mode selected control scheme of this high frequency inverter based on a constant frequency asymmetrical PWM and pulse density modulation control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The practical effectiveness of this power frequency converter is substantially proved on the basis of experimental results from practical design example.