Izuo Hirota

Induction-heated cooking appliance using new quasi-resonant ZVS-PWM inverter with power factor correction

This paper presents a new prototype of a voltage-fed quasi-load resonant inverter with a constant-frequency variable-power (CFVP) regulation scheme, which is developed for the next-generation high-frequency high-power induction-heated (IH) cooking appliances in household applications. This application-specific high-frequency single-ended push-pull inverter using new-generation specially designed insulated gate bipolar transistors (IGBTs) can efficiently operate under a principle of zero-voltage switching pulsewidth modulation (ZVS-PWM) strategy. This low-cost soft-switching inverter using reverse-conducting and reverse-blocking IGBTs is more suitable for multiple-burner-type induction-heating cooking appliances. The operating principle and unique features of a new resonant ZVS-PWM inverter circuit topology is originally described, together with its steady-state power regulation characteristics, which are illustrated on the basis of its computer-aided simulation and experimental results. The ZVS operation condition on power regulation, loss analysis of new IGBTs incorporated into this inverter, and its active filtering performance are discussed for IH cooking appliances.

Latest developments of high-frequency series load resonant inverter type built-in cooktops for induction heated all metallic appliances

This paper deals with the 1st generation prototype of one-stage boost-half bridge (B-HB) series load resonant (SLR) soft-switching high-frequency (HF) inverter with a lossless snubbing capacitor for a variety of induction heating (IH) appliances. The B-HB SLR HF inverter treated here is based upon a simple dual SLR frequency selection strategy changed automatically in accordance with various metal materials of IH loads. In the first place, the triple SLR frequency (three times of switching frequency) operated B-HB inverter is demonstrated for IH of non-magnetic and low resistivity metallic pans/utensils fabricated by aluminum, copper and multi-layer of aluminum and stainless steel. In the second place, the fundamental resonant frequency (switching frequency) operated B-HB SLR HF inverter for IH is also demonstrated of magnetic and high resistivity metallic pans/utensils fabricated by iron, iron cast and stainless steel. Finally, the principle of operation control, implemental and inherent unique features of the B-HB SLR HF inverter employing automatically dual resonant frequency selection scheme for a variety of IH metallic pans/utensils is described from an experimental point of view, along with its operating performance. This 1st generation HF SLR inverter type built-in IH cooktop with two ranges/three ranges has been put into practice in home energy utilizations in all electricity residential systems.

Comparative performance evaluations of IGBTs and MCT in single-ended quasi-resonant zero voltage soft switching inverter

The simple and low-cost operation at zero voltage soft commutation voltage-fed quasi-resonant PFM inverter is widely used, which is more suitable and cost effective for consumer induction heated cooking appliances. This paper presents feasible performance evaluations of each generation IGBT developed and MOS controlled thyristor (MCT) incorporated into the simplest voltage source type quasi-resonant PFM inverter operating in zero voltage soft switching transition mode for induction heated loads. New generation IGBT in addition to MCT have been improved in order to reduce their conduction power losses which are based on their lowered saturation voltage characteristics in addition to high current density. In the first place, each generation IGBT is respectively built and tested on the basis of a single-ended quasi-resonant PFM inverter circuit operating at zero voltage soft switching commutation. In the second place, the power loss-temperature analysis of the latest IGBT with a trench-gate structure is discussed and evaluated from an experimental point of view. In the third place, the further reduced saturation voltage and conduction power loss characteristics of attractive MCT are presented in comparison with the 3rd generation IGBT by using zero voltage high current density soft-switching inverter for consumer high frequency power application.

A novel time ratio controlled high frequency soft switching inverter using 4/sup th/ generation IGBTs

This paper presents a novel prototype of active voltage-clamping capacitor-assisted soft switching PWM inverter operating at a constant frequency variable power (VPCF) regulation scheme, which is suitable for consumer high-power induction-heating cooking appliances. New generation IGBT with a trench gate is particularly improved in order to reduce conduction loss due to its lower saturation voltage characteristics. The soft switching load resonant and quasiresonant inverter using the latest IGBTs designed specially, is evaluated from an experimental point of view.

Practical evaluations of single-ended load-resonant inverter using application-specific IGBT and driver IC for induction-heating appliance

This paper presents an efficient single-ended type high-frequency induction-heating quasi-resonant inverter circuit using a single advanced 2nd generation IGBT for soft-switching and its specially-designed driver IC, which operates at a zero-voltage soft-switching (ZVS) mode under PFM-based power regulation strategy. The generic voltage-fed and current-fed circuit versions of single-ended resonant inverters for home power electronics appliances are systematically proposed and classified on the basis of the soft-switched PFM mode inverter family. The advanced IGBT designed for the application-specific soft-switching and its driver IC are shown for a new induction-heating rice cooker including cooking vessel and evaluated from an experimental point of view. These new technologies are especially developed for quasi-resonant ZVS high-frequency inverter with working coil-linked induction-heating loads. This high-efficiency high-frequency quasi-resonant inverter system with high-power factor correction and sinewave line current shaping functions is practically demonstrated including a high-frequency IGBT with reduced saturation voltage characteristics, and discussed on the basis of high-power density home-power electronic appliances in the next generation.<<ETX>>

Voltage-clamped soft switching PWM inverter-type DC-DC converter for microwave oven and its utility AC side harmonics evaluations

A single-ended quasi-resonant zero voltage soft-switching inverter type DC-DC converter is used to drive the magnetron for a microwave oven. This converter is simple, downsizing, high efficiency and low cost in addition to simple control scheme. However, this power conversion circuit has to control its input power under a condition of ZVS in accordance with the variable frequency regulation. The heater current variation of the magnetron becomes large when the power regulation of this inverter is implemented. The regulation range of input power is to be in order to achieve ZVS operation. For high power application, the peak voltage of IGBT in this inverter becomes large. This paper presents a new topology of the voltage-clamped ZVS-PWM high-frequency inverter-fed DC-DC converter for driving a microwave oven. This paper also describes how to improve line current distortion and power factor on the utility AC power side. Because the anode current of the magnetron must not exceed 1.2 A, because of the lifetime of the magnetron, the voltage-clamped ZVS-PWM high-frequency inverter-fed DC-DC converter is implemented and evaluated under suppression conditions of the anode peak current of the magnetron.

Utility frequency AC connected high frequency AC one stage power processing conversion circuits with boosted DC voltage rail

This paper presents a single phase utility AC connected two-switch boost-half bridge one stage high frequency power conversion circuit topology with boosted DC link and active power filter function, which is more suitable for consumer IH appliances as cooking heater and super heated steamer. The proposed high frequency power converter is composed of power conversion conditioning and processing combined by discontinuous current mode boost type power factor correction converter and half bridge ZVS-PWM high frequency single ended push pull load resonant inverter. This power converter include some advantages such as simple configuration and control scheme, low cost, utility AC side harmonic current PWM for power regulation. Its operating principle is described and discussed herein. In addition to these, the operating performances of the proposed power converter using IGBTs are illustrated and estimated on the basis of simulation and experimental results. Its practical effectiveness as consumer induction heater mentioned above is actually proved from an experimental point of view. Moreover, to extend soft switching operation ranges of this power converter for low power setting, switching frequency selection approach based on switching frequency selected asymmetrical PWM is discussed in this paper

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

Edge resonant soft switching PWM inverter using trench gate IGBTs for induction heating

This paper presents a novel prototype of active voltage-clamping capacitor-assisted edge resonant soft switching PWM inverter operating at a constant frequency variable power (VPCF) regulation scheme, which is suitable for consumer high-power induction-heating cooking appliances. New generation IGBT with a trench gate is particularly improved in order to reduce conduction loss due to its lowered saturation voltage characteristics. The soft switching load resonant and quasiresonant inverter designed using the latest IGBTs is evaluated from an experimental point of view.