Hideki Sadakata

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.

Latest practical developments of triplex series load resonant frequency-operated high frequency inverter for induction-heated low resistivity metallic appliances in consumer built-in cooktops

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

High frequency soft switching inverter for fluid-heating appliance using induction eddy current-based involuted type heat exchanger

This paper presents a high efficiency and high performance continuous fluid-heating appliance in the pipeline system using soft switching high frequency inverter which is base on the electromagnetic induction heating processing. Its operating performance as a hot water producer is evaluated and discussed on the basis of experimental and simulation results.

A comparative evaluation of DCM control and CCM control for soft-switching PFC converter

Harmonic currents generated from the power electric equipment such as IH cooking heaters involve harmful influences to the other equipments connected to the utility grid. As for the IH cooking appliances, adding the PFC converter to the input stage of IH cooking heater is one of the practical solutions to suppress harmonic current influences. In this paper, two operation modes; DCM and CCM for the PFC converter are compared and tested from the view points of magnetic volume and power quality to clarify the suitable operation mode for consumer IH cooking appliance.

A comparison of operation mode for soft-switching PFC converter for induction heating cooking appliance

Harmonic currents generated from the power electric equipment such as IH cooking heaters involve harmful influences to the other equipments connected to the utility grid. As for the IH cooking appliances, adding the PFC converter to the input stage of IH cooking heater is one of the practical solutions to suppress harmonic current influences. In this paper, two operation modes; DCM and CCM for the PFC converter are compared and tested from the view points of magnetic volume and power quality to clarify the suitable operation mode for consumer IH cooking appliance.

Single stage series load resonant ZVS-PWM high frequency inverter operating at one diode conduction and critical ZCS PFC rectifier

This paper presents single stage series load resonant ZVS-PWM high frequency inverter which operates one diode conduction mode and critical ZCS PFC rectifier for induction heating (IH) applications. This single stage inverter is composed of a single phase PFC rectifier operating at one diode conduction mode and asymmetrical ZVS-PWM high frequency resonant inverter without the interlink bulky electrolytic capacitor stage for boosted DC voltage smoothing. The operating principle of the proposed single stage inverter is described by using the switching mode equivalent circuits in addition to the simulated operating voltage and current waveforms. The single stage inverter design to achieve single diode conduction mode for diode bridge rectifier is discussed by simulation analysis. The operating performances of this single stage inverter are also illustrated which includes its utility frequency AC (UFAC) to high frequency AC (HFAC) power regulation characteristics, soft switching operating range and UFAC side distortion power factor as well as UFAC side line current harmonics by FFT analysis. The effectiveness of this single stage inverter using IGBTs for consumer high-frequency IH appliances is evaluated and proved on the basis of simulation results.