Takaaki Okude

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 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 (IH) applications. Its operating principle and the operation modes are 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 IGBTs are illustrated, which includes HFAC power regulation ranges and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation 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 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. This power frequency converter practical effectiveness is substantially proved on the basis of experimental results from practical design example.

Utility AC Frequency 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 (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 (IH) applications. Its operating principle and the operation modes are 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 IGBTs are illustrated, which includes HFAC power regulation ranges and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation 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 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. This power frequency converter practical effectiveness is substantially proved on the basis of experimental results from practical design example.

A Switched-Capacitor Lossless Inductor ZCS Snubber-Assisted Series Load Resonant High Frequency Inverter with Dual Mode Pulse Modulation Scheme

In this paper, a novel type auxiliary active edge resonant snubber assisted zero current soft switching pulse modulation series load resonant inverter using IGBT power modules is proposed for cost effective consumer high-frequency induction heating (IH) appliances. Its operating principle in steady state is described by using each switching mode equivalent operating circuits. The new multi resonant high-frequency inverter with series load resonance and edge resonance can regulate its high frequency output power under a condition of a constant frequency zero current soft switching (ZCS) commutation principle on the basis of asymmetrical pulse width modulation (PWM) control scheme. The consumer brand-new IH products using proposed ZCS-PWM high-frequency inverter is evaluated and discussed as compared with conventional type inverter on the basis of experimental results. In order to extend ZCS operation ranges under a low power setting PWM as well as to improve efficiency, the high frequency pulse density modulation (PDM) strategy is demonstrated for high frequency multi resonant inverter. Its practical effectiveness is substantially proved from an application point of view