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속도 Observer를 이용한 유도전동기 센서리스 벡터제어
이수원,전칠환,이성룡 국립7개대학공동논문집간행위원회 2002 공업기술연구 Vol.2 No.-
The stability for a speed sensorless vector control of an induction machine has been studied. These studies show that the sensorless control is apt to be more unstable than the control with sensor on the variation for stator resistance, rotor resistance and system parameters of the machine. First, this paper investigates the start-up and transient characteristics when the inertia, J, changes and the rotor resistance, R_r, changes respectively for a step change of a speed reference, ω_r. Then, the new speed estimation algorithms with no effects on the parameters variation of the machine and the system is proposed. The proposed method is to implement the observer using voltage, current and constant of the machine. The results are verified by simulation.
The Voltage-fed High Frequency Resonant Inverter Using Induction Heated Dry Steam Generator
Chil-Ryong Kim(김칠용),Jong-Kurl Lee(이종걸),Sang-Hwa Jung(정상화),Sang-Pil Mun(문상필),Sang-Don Kim(김상돈),Mutsuo Nakaoka 한국조명·전기설비학회 2008 한국조명·전기설비학회 학술대회논문집 Vol.2008 No.5월
This paper presents an innovative prototype of a new conceptual electromagnetic induction-based fluid heating appliance using voltage-ted type series capacitor-compensated load resonant high-frequency IGBT inverter with a phase-shifted PWM and a power factor correction schemes. Its operating characteristics in steady-state are illustrated including unique features and evaluated on the basis of its computer simulation and experimental results of 10kw breadboard appliance for hot water producer and superheated steamer. The promising cost effective inverter-fed boiler appliances lor electromagnetic induction-heated type fluid-heating in the pipeline systems are proposed for induction-heated boiler, super heat steamer, high temperature water producer, hot gas producer and metal catalyst heating tor exhaust gas cleaning in engine, which are more suitable and acceptable for industrial, chemical, and censurer energy utilization for household and business from a practical point of view.
황형칠 ( Hyeong-chil Hwang ),공룡 ( Ryong Kong ),강옥화 ( Ok-hwa Kang ),권동렬 ( Dong-yeul Kwon ) 대한본초학회 2018 大韓本草學會誌 Vol.33 No.5
Objectives : The aim of this study is to investigate the preventive effect of Puerariae Flos ethanol extract (PE) on methionin and choline deficient (MCD)-diet-induced Nonalcoholic fatty liver disease (NAFLD) in C57BL/6J mice. Methods : In the in vivo experiments, C57BL/6J mice were divided into 4 groups; Normal group, Control group, MCD+PE 100 group, and MCD+PE 300 group. After 4 weeks, body weight, liver weight, biochemical parameters for liver function test, histological changes, reverse transcription polymerase chain reaction (RT-PCR), and Western blot were assessed. Results : Mice lost body weight with the MCD-diet and the MCD+PE 100 group and MCD+PE 300 groups lost less than the control group, though showed no statistical significance. Liver weights were decreased by the MCD diet, but MCD+PE 300 groups were increased significantly. In the liver function test, all the values were decreased with the MCD-diet, MCD+PE 100 group and MCD+PE 300 groups were increased significance. In histological findings of the livers, MCD-diet induced severe fatty accumulation in the livers, but this fatty change was reduced in the MCD+PE 100 group and MCD+PE 300 groups was inhibited respectively. In lipid accumulation factors (such as SREBP-1c, C/EBPα, PPAR-γ), MCD+PE 100 group and MCD+PE 300 groups showed inhibitory effect on liver lipogenesis by reducing associated gene expressions caused by MCD diet. Conclusions : We were able to know that Puerariae Flos ethanol extract (PE) shown hepatoprotective effects via a decrease on the hepatic lipogenesis factors in the experimental NAFLD Models.
부하전압 안정화 기능을 갖는 계통 연계형 분산전원시스템의 설계
이성룡(Seong-Ryong Lee),전칠환(Chil-Hwan Jeon),이수원(Su-Won Lee),고성훈(Sung-Hun Ko) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7
본 논문은 우리나라와 같은 안정된 계통(Strong Grid)에서 계통전압이 한전배전계통 공급기준의 전압변동률 ±6%(220V±13V)이내에서 변화할 경우 계통 역률이 0.9 이상이고 부하전압의 변동이 거의 없도록 계통 연계형 전압제어형 전압원인버터(VCVSI)에 적합한 최대 전력제어각과 각각 최적의 시스템 용량(계통, 디커플링 인덕터, VCVSI)을 구하고, 유효전력을 100% 공급하기 위한 파라미터 설계 방법을 제시하였다.
황금작약탕(黃芩芍藥湯)의 RAW 264.7 대식 세포에서의 항염증 효과에 관한 연구
김마룡 ( Ma Ryong Kim ),강옥화 ( Ok Hwa Kang ),김성배 ( Sung Bae Kim ),강희정 ( Hee Jung Kang ),김지은 ( Ji Eun Kim ),황형칠 ( Hyeong Chil Hwang ),김인원 ( In Won Kim ),권동렬 ( Dong Yeul Kwon ) 대한본초학회 2013 大韓本草學會誌 Vol.28 No.1
Objectives : Hwanggeumjakyak-tang (huangqin shaoyao tang, HJT) has been used to treat acute enteritis in traditional oriental medicine. However, there has been a lack of studies regarding the effects of HJT on the inflammatory activities and effector inflammatory disease mechanism about macrophage before is not known. So we examined the effect of HJT water extract on pro-inflammatory mediators in lipopolysaccharide (LPS) - stimulated mouse macrophage, RAW 264.7 cells, Methods : Cells were treated with 2 ug/mL of LPS 1 h prior to the addition of HJT. Cell viability was measured by MTS assay. The production of nitric oxide (NO) was determined by reacting cultured medium with Griess reagent. The expression of cyclooxygenase-2 (COX-2), inducible NO synthase (iNOS) and mitogen-activated protein kinases (MAPKs) was investigated by Western blot, RT-PCR. The content of level of cytokines (prostaglandin (PG) E₂, interleukin (IL)-6, IL-12, Tumor necrosis factor-alpha (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) in media from LPS-stimulated Raw 264.7 cells was analyed by ELISA kit, Results : HJT inhibited the production of NO, PGE₂, IL-6 as well as the expressions of iNOS, COX-2 but did not inhibit the production of IL-12, TNF-α, MCP-1 in the murine macrophage, RAW 264.7 cells. HJT also had suppression effects of LPS- induced MAPKs activation, Conclusion : These results suggest that HJT has an anti-inflammatory therapeutic potential, which may result from inhibition of MAPK phosphorylation, thereby decreasing the expression of pro-inflammatory genes.
이성룡(Seong-Ryong Lee),전칠환(Chil-Hwan Jeon),고성훈(Sung-Hun Ko),조아란(Ah-Ran Cho) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7
This paper presents a grid-connected photovoltaic (PV) system with direct coupled power quality control (PQC) algorithm, which uses an inner current control loop (PRT : polarized ramp time) and outer feedback control loop to improve grid power quality and maximum power point tracking (MPPT) of PV arrays. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, single stage CCVSI (Current Controlled Voltage Source Inverter) is used. The proposed system operation has been divided into two modes (sunny and night). In night mode, the proposed system operates to compensate the reactive power demanded by nonlinear or variation in loads. in sunny mode, the proposed system performs PQC to reduce harmonic current and improve power factor as well as MPPT to supply active power from the PV arrays simultaneously. it is shown that the proposed system improves the system utilization factor to 100%, which is generally low for PV system (20%). To verify the proposed system, a comprehensive evaluation with theoretical analysis and simulation results are presented.
Sang-Pil Mun,Chil-Ryong Kim,Jong-Kurl Lee,Man-Kyu Park,Soon-Kurl Kwon 한국조명·전기설비학회 2008 조명·전기설비학회논문지 Vol.22 No.3
This paper presents a simple circuit topology of the auxiliary active quasi-resonant DC link snubber-assisted three phase voltage source soft-switching inverter for small scale PM motor drive applications. The pulse processing drive circuit interface and its soft-switching operation are discussed from an experimental point of view. Moreover, its conductive noise is measured and evaluated for electrical AC servo motor drive as compared with that of the conventional hard switching inverter.
Induction Heating PWM High Frequency Inverter using New Active Auxiliary Resonant Snubber
Sang-Pil Mun,Chil-Ryong Kim,Jong-Kurl Lee,Hong-Sin Kim,Sang-Hwa Jung,Soon-Kurl Kwon 한국조명·전기설비학회 2008 조명·전기설비학회논문지 Vol.22 No.3
This research presents a new active auxiliary resonant snubber with for induction heating PWM high frequency inverter solving the problem of induction heating PWM high frequency inverter circuit which is using widely in the practical application of an induction heating apparatus, the soft switching operation and power control are impossible when the lowest power supply in the active auxiliary resonant snubber with for induction heating PWM high frequency inverter. The inverter circuit which is attempted by the on-off operation of a switch has the effect of reducing the power loss due to soft switching and high frequency switching. This confirms that power regulation is possible on a continuous basis from 0.25[kW] to 2.84[kW] where the duty factor (D) changes from 0.08 to 0.3 under zero current switching which operates by an asymmetrical pulse width modulating control. The power conversion efficiency is 95[%]. Due to these results, the active auxiliary resonant snubber for an induction heating PWM high frequency inverter is considered effective as a source of induction heating.