• Title/Summary/Keyword: Induction heating

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Safety Evaluation for Pressure Rice Cooker Oven using Experiment (실험을 이용한 전기보온압력밥솥 오븐의 안전도 평가)

  • Lee, Seung-Pyo;Koh, Byung-Kab;Ha, Sung-Kyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.6
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    • pp.1541-1547
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    • 2008
  • Because of good taste and quick cooking, the induction heating type pressure rice cooker is widely used. Since pressure is applied to oven structure, it should be necessary to check the safety evaluation. In this paper, strain gauge experiment is performed in order to evaluate the oven's strain and its result is compared with that of structural analysis. And water test is performed to evaluate the oven's permanent deformation. The result is also compared with that of structural analysis. By using these experiments and analyses the safety evaluation method of the oven is suggested.

Characteristic Estimation of Single-Stage Active-Clamp Type High Frequency Resonant Inverter (단일 전력단 능동 클램프형 고주파 공진 인버터의 특성 평가)

  • 원재선;강진욱;김동희
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.2
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    • pp.114-122
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    • 2004
  • This paper presents a novel single-stage active-clamp type high frequency resonant inverter. The proposed topology is integrated full-bridge boost rectifier as power factor corrector and active-clamp type high frequency resonant inverter into a single-stage. The input stage of the full-bridge boost rectifier works in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that a boost converter makes the line current follow naturally the sinusoidal line voltage waveform. By adding additional active-clamp circuit to conventional class-E high frequency resonant inverter, main switch of inverter part operates not only at Zero-Voltage-Switching mode but also reduces the switching voltage stress of main switch. Simulation results have demonstrated the feasibility of the proposed high frequency resonant inverter. Characteristics values based on characteristics estimation through circuit analysis is given as basis data in design procedure. Also, experimental results are presented to verify theoretical discussion. This proposed inverter will be able to be practically used as a power supply in the fields of induction heating applications, fluorescent lamp and DC-DC converter etc.

A Study on Single-Stage High-Power-Factor Electronic Ballast for Discharge Lamps Operating in Critical Conduction Mode (임계모드에서 동작하는 단일 전력단 고역률 방전등용 전자식 안정기에 관한 연구)

  • Seo Cheol-Sik;Park Jae-Wook;Sim Kwang-Yeal;Kim Hae-Jun;Won Jae-Sun;Kim Dong-Hee
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.12
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    • pp.601-608
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    • 2005
  • This paper presents a novel single-stage high-power-factor electronic ballast for fluorescent lamps operating in critical conduction mode. The proposed topology is based on integration of boost converter as power factor corrector(PFC) and a half-bridge high frequency parallel resonant inverter into a single stage. The input stage of the boost converter is operating in critical conduction mode for positive and negative half cycle voltage respectively at line frequency(60Hz). So that a boost converter makes the line current follow naturally the sinusoidal line voltage waveform. The simulated and experimental results for 100W fluorescent lamps operating at 42kHz switching frequency and 220V line voltage have been obtained. This proposed inverter will be able to be practically used as a power supply in various fields as induction heating applications, fluorescent lamp and DC-DC converter etc.

Characteristic Estimation of Single-Stage High Frequency Resonant Inverter Link Type DC-DC Converter (단일 전력단 고주파 공진 인버터 링크형 DC-DC 컨버터의 특성평가)

  • Won, Jae-Sun;Kim, Hae-Jun;Park, Jae-Wook;Nam, Seung-Sik;Seo, Cheol-Sik;Kim, Dong-Hee
    • Proceedings of the KIEE Conference
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    • 2003.07b
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    • pp.1190-1192
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    • 2003
  • This paper presents a novel single-stage high frequency resonant inverter link type DC-DC converter using zero voltage switching with high input power factor. The proposed high frequency resonant converter integrates half-bridge boost rectifier as power factor corrector (PFC) and half-bridge resonant converter into a single stage. The input stage of the half-bridge boost rectifier is working in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that boost converter make the line current follow naturally the sinusoidal line voltage waveform. Experimental results have demonstrated the feasibility of the proposed DC-DC converter. This proposed converter will be able to be practically used as a power supply in various fields as induction heating applications, DC-DC converter etc.

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Compression D/B for Liquid Segregation Control in Semi-Solid Forming Process and Its Application (반용융 성형공정에 있어서 액상편석제어를 위한 압축 D/B 및 응용)

  • 정경득
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.06a
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    • pp.15-32
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    • 1999
  • A relationship between stress and stain is very important to design a die to avoid defects of products during semi-solid forming process. Since the liquid will be of eutectic composition in alloys liquid segregation will result in significant or undesirable situation. The materials used in this experiment are A 357. A390, Al2024 alloys that is fabricated by the electro-magnetic stirring process from Pechiney in France. The compression test was performed by induction heating equipment and MTS. In order to prevent the liquid segregation these measured temperature would be useful to control of strain rate during compression test. The liquid segregation is controlled as change of the strain rate and solid fraction during the compression process, The characteristics of flow between solid and liquid phase considering liquid segregation is examined through the above experiments. In the case of medium and high volume fractions of solid the distribution of strain rate is calculated by using compression test data of semi-solid materials (SSM). The thixoforming experiments with the designed die are carried out successfully. The die filling patterns of SSM for variation of die temperature and pressing force have been investigated. The hardness of the thixoformed scroll products is evaluated in terms of the microstructure for each position.

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Development of Heater Driven by Motor by Using Eddy Current (와전류 발열장치를 응용한 모터 구동형 히터 개발)

  • Chai, Yong-Yoong;Yoon, Kwang-Yeol
    • The Journal of the Korea institute of electronic communication sciences
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    • v.14 no.5
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    • pp.935-942
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    • 2019
  • This paper descries the operation of a heater which was designed to control a motor that generates an eddy current. As the motor drives the rotor of an eddy current heater, magnetic fields are provided within the air gap between an eddy current heater's rotor and stator. Throughout the research, a rotor composed of 8 and 16 pieces of magnets was used to analyze which are the factors that affect the efficiency of this equipment. Test results showed that the magnetic fields are influenced by variable functions including the velocity of a motor and the quantity of magnets composing a rotor.

Input Voltage Selection Methodology to Improve Power Transfer Efficiency of Half-Bridge Series Resonant Inverter Employing High Turn-numbered Coil for Induction Heating Application (높은 턴 수의 코일을 탑재한 유도 가열 장치용 하프 브릿지 인버터의 전력 변환 효율 향상을 위한 입력전압 선정 기법)

  • Jin, Juil;kim, Mina;Jung, Jee-Hoon
    • Proceedings of the KIPE Conference
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    • 2019.07a
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    • pp.156-158
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    • 2019
  • 낮은 저항 용기를 가열할 수 있는 유도 가열 장치는 유도가열 장치용 하프 브릿지 직렬 공진형 인버터의 높은 입력 전압과 높은 턴 수의 코일을 통해 낮은 저항의 용기를 가열한다. 그러나 자성체 용기는 높은 턴 수의 코일에서 높은 저항 값을 가지므로 적절한 전력을 내기 위해서는 높은 입력 전압이 필요하다. 이러한 경우 부스트 토폴로지의 역률 개선 회로를 사용할 수 있다. 하지만 입력 전압의 변동에 따라 직렬 공진형 인버터의 출력 전력 제어를 위한 동작 점 변동이 필요하므로 인버터의 손실이 변동한다. 본 논문에서는 낮은 저항 용기를 가열하기 위하여 높은 턴 수의 코일을 탑재한 유도 가열 장치용 하프 브릿지 직렬 공진형 인버터에서 자성체 용기의 가열 시 입력 전압 변동에 따른 인버터의 손실 분석을 통해 최적의 입력전압 조건을 선정하고자 한다. 제안하는 입력전압 선정 기법은 2-kW 급 유도 장치용 하프 브릿지 직렬 공진형 인버터 시 제품을 통해 타당성을 검증한다.

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Cetyl Trimethyl Ammonium Bromide-coated Nickel Ferrite Nanoparticles for Magnetic Hyperthermia and T2 Contrast Agents in Magnetic Resonance Imaging

  • Lee, Da-Aemm;Bae, Hongsubm;Rhee, Ilsum
    • Journal of the Korean Physical Society
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    • v.73 no.9
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    • pp.1334-1339
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    • 2018
  • Spherical nickel ferrite nanoparticles were synthesized using the thermal decomposition method and coated with cetyl trimethyl ammonium bromide (CTAB) after the synthesis. Transmission electron microscopy images showed that the average diameter of the particles was 9.40 nm. The status of the CTAB-coating on the surface of the particles was checked using Fourier-transform infrared spectroscopy. Their hysteresis curve showed that the particles exhibited a superparamagnetic behavior. The $T_1$ and the $T_2$ relaxations of the nuclear spins were observed in aqueous solutions of the particles with different particles concentrations by using a magnetic resonance imaging (MRI) scanner, which showed that the $T_1$ and the $T_2$ relaxivities of the particles in water were $0.57mM^{-1}{\cdot}s^{-1}$ and $10.42mM^{-1}{\cdot}s^{-1}$, respectively. In addition, using an induction heating system, we evaluated their potentials for magnetic hyperthermia applications. The aqueous solution of the particles with a moderate concentration (smaller than 6.5 mg/mL) showed a saturation temperature larger than the hyperthermia target temperature of $42^{\circ}C$. These findings show that the CTAB-coated nickel ferrite particles are suitable for applications as $T_2$ contrast agents in MRI and heat generators in magnetic hyperthermia.

Hydrogen Aging During Hole Expanding Tests of Galvanized High Strength Steels Investigated Using a Novel Thermal Desorption Analyzer for Small Samples

  • Melodie Mandy;Maiwenn Larnicol;Louis Bordignon;Anis Aouafi;Mihaela Teaca;Thierry Sturel
    • Corrosion Science and Technology
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    • v.23 no.2
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    • pp.145-153
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    • 2024
  • In the automotive industry, the hole expanding test is widely used to assess the formability of punched holes in sheets. This test provides a good representation of formability within the framework defined by the ISO 16630 standard. During hole expanding tests on galvanized high strength steels, a negative effect was observed when there was a delay between hole punching and expansion, as compared to performing both operations directly. This effect is believed to be caused by hydrogen aging, which occurs when hydrogen diffuses towards highly-work hardened edges. Therefore, the aim of this study is to demonstrate the migration of hydrogen towards work-hardened edges in high strength Zn-coated steel sheets using a novel Thermal Desorption Analyzer (TDA) designed for small samples. This newly-developed TDA setup allows for the quantification of local diffusible hydrogen near cut edges. With its induction heating and ability to analyze Zn-coated samples while reducing artifacts, this setup offers flexible heat cycles. Through this method, a hydrogen gradient is observed over short distances in shear-cut galvanized steel sheets after a certain period of time following punching.

Chemical Changes of the Deep Fat Frying Oils Used Commercially (일반시장에서 튀김식품에 사용된 기름의 화학적 변화)

  • Joo, Kwang-Jee;Ha, Gy-Sook
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.18 no.3
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    • pp.247-254
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    • 1989
  • In deep-fat frying, the fats and oils are used over and over again, and moisture and air are mixed in to the hot oil. Many reports related to these fats and oils have been established that thermal and oxidative decomposition products and polymers formed under the conditions of deep fat frying are harmful to health. This work was carried out with 3 domestic frying oils and 6 used oils commercially, and that there were difficulties in finding a good definition between fresh oil and used oil with adding unheated oil. As starting materials, commercially used soybean oil and rapeseed oil already passed over induction period in the lipids oxidation standard. From the qualitative point of view, they were inferior to domestic frying oils. Free fatty acid and peroxide value of heated oils were increased gradually by the time pass whereas iodine value were decreased. After adding unheated oil to the heated oil, these values were restored to that of initial levels. On the other hand, content of polar components in the heated oil were directly related to the heating time. This result showed that polar compounds may be a clear indicator of used oils. Fatty acid composition in the used oils, unsaturated fatty acids such as linoleic and linolenic acid decreased while saturated fatty acid content increased with heating.

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