Utility Frequency AC to High Frequency AC Power Converter with Boost-Half Bridge Single Stage Circuit Topology

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit incorporating boost-half bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode equivalent circuits and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) 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 power converter practical effectiveness is substantially proved based on experimental results from practical design example.