Toshiaki Iwai

Two-switch boost-half bridge and boost active clamped ZVS-PWM AC-AC converters for consumer high frequency induction heater

This paper presents a two-switch boost-half bridge one stage power conversion circuit topology of commercial single-phase utility frequency AC fed ZVS-PWM power converter with harmonic current suppression and unity power factor correction functions. This cost effective utility frequency AC (UFAC) to high frequency AC (HFAC) power converter is developed for consumer induction heating (IH) appliances. This two-switch boost-half bridge one stage UFAC to HFAC power converter includes some advantages as simple configuration and control scheme, low cost, utility AC side harmonic current reduction with unity power factor, and constant frequency ZVS-PWM for power regulation. Its operating principle is described and discussed herein. In addition to this, its operating performances are illustrated and estimated on the basis of simulation and experimental results. An active voltage clamped ZVS-PWM high frequency inverter with boost function and its characteristics are also evaluated as compared with two-switch boost-half bridge power converter treated here

PWM/PDM dual mode controlled soft switching multi resonant high-frequency inverter

In this paper, a novel type auxiliary active resonant capacitor snubber assisted zero current soft switching pulse modulation single-ended push pull (SEPP) series load resonant inverter with two auxiliary resonant lossless inductor snubbers is proposed for consumer high-frequency induction heating (IH) appliances. Its operating principle in steady state is described by using each mode equivalent circuits. The new multi resonant high-frequency inverter can regulate its output power under a condition of a constant frequency zero current soft switching (ZCS) commutation principle on the basis of asymmetrical PWM control scheme. The consumer brand-new IH products using proposed ZCS-PWM series load resonant SEPP high-frequency inverter is evaluated and discussed as compared with conventional high-frequency inverter on the basis of experimental results. In order to extend ZCS operation ranges under a low power setting PWM, the 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

A new zero current soft switching duty cycle controlled high frequency multi resonant inverter for consumer power applications

In this paper, a novel type auxiliary active edge resonant snubber assisted zero current soft switching pulse modulation single-ended push pull (SEPP) 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 series load resonant SEPP high-frequency inverter using IGBTs is evaluated and discussed as compared with conventional high-frequency 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