• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.51-57
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• 1998

This paper proposed a novel SIT high frequency resonant inverter having drive signal phase shift control function. Phasor control type inverters using SIT can realize a power conversion on the high switching frequency with low switching loss. Especially, the high output power can be abstained by connecting the output voltage of two unit inverters In serIes. The stability of system using protection circuit for over current and the automatic follow-up control with load variation by PLL is presented. This inverter produce approximately sinusoidal waveform at a high frequency, switching frequency ranging from 180[kHz] to 220[kHz], and is applied to the 2[kW] induction heating. The operating characteristics of this inverter circuit are discussed from a theoretical point of view and compared with experimental results. results.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.73-76
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• 2003

A zero voltage soft switching inverter using active clamp is presented for induction heating application. This converter have long been attractive because of its simplicity, high efficiency, and low cost compared to other schemes. In addition to those merits, Input power factor can be improved with a variable frequency control. In this paper, it describe the control method and operational principle to improve a power factor with a single stage US converter using active clamp for induction heating application.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.2
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• pp.230-237
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• 2004

This paper suggests and demonstrates a novel flow measurement technique: tunable AC thermal anemometry that allows simple integration, robust measurement, and extremely high accuracy. The principle and simple theoretical analysis of the technique are presented. To find the optimal condition at which the phase lag becomes most sensitive to flow speed change, the phase lag was measured scanning the heating frequency from 1 to 100 Hz, while the flow speed of ethanol was increased stepwise from 0 to 40 mm/s. The sensitivity of phase lag depended on the heating frequency and the flow speed. It was possible to measure the flow speed of 0.7 mm/s with the resolution of 0.1 mm/s at 4 Hz.

• Korean journal of food and cookery science
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• v.31 no.3
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• pp.360-369
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• 2015

The objective of this study was to develop remedies to improve sanitary quality of school meals. To analyze the usage of potentially hazardous foods, menus from 180 school foodservice establishments were collected through school websites. Statistical analyses were conducted using the SPSS package program (ver. 20.0). The results of this study are as follows: analysis of the foodservice production process revealed that the following were employed: heating process (70.5%), non-heating process (16.3%), and after-heating process (13.2%). In addition, the cooking methods used for side dishes were: stir-frying (22.1%), saengchae (21.3%), sukchae (15.2%), jorim (12.4%), deep-frying (10.2%), and grilling (9.5%). Overall, 64 menu items known to pose potential microbiological hazards were offered a total of 2,671 times. The usage frequency was high for bibimbap, pork-bulgogi, cucumber-saenchae, seasoned bean sprouts namul, seasoned spinach-namul, and korean cabbage-geotjeori. In conclusion, in order to increase the sanitary quality of school meals, menus or foods that contain microbiological hazards should prepared very carefully with respect to time and temperature management during food production. Also, school foodservice employees must possess proper food safety knowledge and techniques for applying the HACCP system to prevent foodborne illness.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.6
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• pp.90-95
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• 1997

In designing a resonant circuit of the inverter which puts induction heating with high frequency to the load, an inductance L of the circuit, the coupling coefficient of a transformer transfering the output power to load, and the coupling coefficient of load circuit heating with coil affect to the output power of a resonant circuit, the circuit Q and the frequency. Those characteristics of the circuit are analyzed through Thevenan's equivalent circuit of the coupling coefficient type which is derived from the T-type equivalent circuit of a transformer. On this equivalent circuit, the impedance of a transformer referred to its primary side is not only proportional the square of turn ratio, nZ, but also the square of coupling coefficient, K2 This paper proposed a more accurate fundamental method to design a resonant circuit of the inverter by using the Thevenan's equivalent circuit.

• Journal of Sensor Science and Technology
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• v.25 no.1
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• pp.8-12
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• 2016

A planar, light-weight, and low-cost notch filter structure is required for the KSTAR ECEI (Electron Cyclotron Emission Imaging) system to protect the mixer arrays from spurious plasma heating power. Without protection, this heating power can significantly degrade or damage the performance of the mixer array. To protect mixer arrays, a frequency selective surface (FSS) structure is the suitable choice as a notch filter to reject the spurious heating power. The FSS notch filter should be located between the lenses of the ECEI system. This paper presents a 170 GHz FSS notch filter for the KSTAR ECEI sensor application. The design of such an FSS notch filter is based on the single-sided square loop geometry, because that makes it relatively insensitive to the incident angle of incoming wave. The FSS notch filter exhibits high notch rejection with low pass-band insertion loss over a wide range of incident angles. This paper also reviews the simulated and measured results. The proposed FSS notch filter might be implemented in other millimeter-wave plasma devices.

• Journal of IKEEE
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• v.22 no.3
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• pp.870-873
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• 2018

This paper presents the high frequency resonant inverter using ZVS(Zero Voltage Switching) known as the soft switching technology, which can reduce the turn-on and turn-off switching losses. Also, the analysis of the proposed resonant inverter is described by adopting normalized parameters, and its operating characteristics are evaluated according to the switching frequency and parameters. An example of 1.3[kW] IH-Jar design technique is presented based on the characteristic values obtained from the theoretical analysis. To prove the validity of the theoretical analysis, the experimental results using IGBT as the switching devices are additionally presented. In the future, it can be practically used in various power systems such as induction heating cooking, IH-Jar etc.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1193-1195
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• 2002

This paper presents Active-clamp Class-E high frequency resonant inverter with single-stage. The proposed circuit is integrated Active-c class-E circuit to boost converter with the funct power factor correction. Boost converter is opera positive and negative half cycle respectively at frequency(60Hz), operating in Discontinuous Con Mode(DCM) of boost converter performs high p factor. By adding active-clamp circuit in Cl inverter, main switch of inverter part is operat only ZVS(Zero Voltage Switch), but also reduce switching voltage stress of main switch. Simulation result using Psim4.1 show that the p prove the validity of theoretical analysis. This proposed inverter will be able to be pract used as a power supply in various fields are ind heating applications, DC-DC converter etc.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.287-291
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• 2002

This paper presents active-clamp class-E high frequency resonant inverter with single-stage. The proposed circuit is integrated active-clamp class-E circuit to boost converter with the function of power factor correction. Boost converter is operated in positive and negative half cycle respectively at line frequency(60Hz), Such a operating in discontinuous conduction mode(DCM) of boost converter performs high power factor. By adding active-clamp circuit in class-E inverter, main switch of inverter part is operated not only ZVS(Zero Voltage Switch) but also reduced the switching voltage stress of main switch. This paper shows that simulation result using Psim 4.1 prove the validity of theoretical analysis. This proposed inverter will be able to be practically used as a power supply in various fields as induction heating applications, DC-DC converter etc.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.2
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• pp.91-98
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• 1998

The current-fed high frequency inverter with separated parallel resonant capacitor is presented in this paper. The analysis of the proposed circuit is generally described by using normalized parameter, and are evaluated characteristics of the circuit.In addition, this paper proves the propriety of theoretical analysis in terms of the experimental waveforms using the switching device MOSFET. In the future, the proposed inverter will expected that it can be practically used as the high frequency power source for induction heating etc.ng etc.