• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.999-1001
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• 1995

In this study, the algorithm of optimal parameter inference is proposed. At this inferring method, we tried to acquire the follow-up to reference pattern through comparing the plant output pattern with random reference pattern. As an inference method, the fuzzy theory was applied and the proposed algorithm was proved by computer simulation.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.612-614
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• 2003

현재 시행 중인 부하관리 프로그램들은 거의 대부분 간접부하관리 방식에 의존하고 있으며, 이러한 간접부하관리 프로그램들은 요금혜택에 기반을 두고 있다. 직접부하관리가 우리나라에 도입된 것은 2001년 5월이며, 이러한 직접부하관리 프로그램은 간접부하관리 프로그램에 비하여 다음과 같은 다양한 장점을 가지고 있다. 1) 부하관리 자원의 이용 가능성(availability)이 간접부하관리에 비하여 상대적으로 높다는 것과, 2) 기존의 간접부하관리 프로그램에서의 성과계량, 즉, 부하관리 실시에 따른 피크 수요감소량을 명확하게 알 수 있으므로 전력회사가 장단기 수급계획을 수립하는데 보다 확실하게 이를 고려할 수 있다는 것과, 3) 부하차단의 주체가 전력회사가 되므로 간접부하관리 방식이 안고 있는 수용가 부하차단의 불확실성이 낮아지며, 4) 궁극적으로 비용효과가 간접부하관리보다 큰 유용한 자원이다. 본 논문에서는 이러한 직접부하제어자원의 개요와 전력시장 참여 현황 및 해외사례를 소개하고자 한다.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.640-645
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• 2003

최근의 도시철도 추진시스템은 VVVF 인버터로 제어되기 때문에 대부분 회생제동의 기능을 갖추고 있다. 회생제동 시 발생되는 전력은 그 때의 동일 노선에서 역행하고 있는 열차에 추진에너지로 사용되는 것이 가장 효율적이나 그것이 가능하지 않을 경우 혹은 그렇게 사용하고도 남는 잉여회생에너지가 발생할 경우 변전소의 회생용 인버터를 통해 역사 내에서 소비되는 방법도 많이 응용되고 있다. 이를 위해서는 회생용 인버터가 변전소 내에 설치되어야 한다. 본 논문에서는 경량전철시스템의 급전 시스템에서 이러한 회생용 인버터의 경제성분석과 적정용량 및 위치에 관에 논의된다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.11
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• pp.671-679
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• 2004

This paper presents the on-line current controller tuning method of grid-connected inverter using PSO(particle swarm optimization) technique for minimizing the harmonic current. Synchronous frame PI current regulator is commonly used in most distributed generation. However, due to the source voltage distortion, specially in weak AC power system, current may contain large harmonic components, which increase THD(total harmonic distortion) and deteriorates power quality. Therefore, some tuning method is necessary to improve response of current controller. This paper used the PSO technique to tune the current regulator and through simulation and experiments, usefulness of the tuning method has been verified. Especially in simulating the tuning process, ASM(average switching model) of inverter is used to shorten execution time.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.115-117
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• 2008

최근 가전기기의 고집적화와 고효율을 위한 연구가 이슈화 되고 있다. 이러한 고효율과 고집적화의 효과를 얻기 위한 방법으로 Multiphase LLC 공진 컨버터가 연구되고 있으며 본 논문에서는 제어회로를 간단화 하면서 Two Phase Interleaved LLC 공진 컨버터를 제안하였고 총 250W급 변압기를 적용하여 실험한 결과에 대하여 서술 하였다.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.410-412
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• 1995

From the cost-effective product point of view, it is very important to design a new current controller with the highest utilization factor of current capacity of power devices. This paper deals with a state-deadbeat current controller for PWM converters, which shows the fastest current control response without overshoot irrespective of the saturation of control voltage. No-overshoot control response means that the current capacity could be fully utilized in the control sense. Simulational results done by Matlab's Simulink show good current control characteristics.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.8-15
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• 2024

This paper proposes a linear model predictive control of 6-DOF remotely operated underwater vehicles using nonlinear robust internal-loop compensator (NRIC). First, we design a integrator embedded linear model prediction controller for a linear nominal model, and then let the real model follow the values calculated through forward dynamics. This work is carried out through an NRIC and in this process, modeling errors and external disturbance are compensated. This concept is similar to disturbance observer-based control, but it has the difference that H_∞ optimality is guaranteed. Finally, tracking results at trajectory containing the velocity discontinuity point and the position tracking performance in the disturbance environment is confirmed through the comparative study with a traditional inverse dynamics PD controller.

• KSBB Journal
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• v.19 no.1
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• pp.17-26
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• 2004

In this study the extracellular production of 5-aminolevulinic aicd (ALA) by recombinant E. coli BL2l (DE3) pLysS harboring the plasmid pFLS45 are investigated. Optimum concentrations of succinic acid and glycine for cell growth and ALA production were found to be 30 mM and 15 mM, respectively. Levulinic acid (LA) as an inhibitor of ALAD was added to the culture medium in the end of exponential cell growth phase and its optimum concentration was 30 mM. Growth of recombinant E. coli BL2l (DE3) pLysS (pFLS45) was largely dependent upon the pH value of culture medium. When the pH of culture medium was in the range of 6.0 and 6.5, high cell mass and ALA production were obtained. IPTG induction for the expression of the fusion gene did not enhance the production of ALA. Recombinant cell grew at 30't faster than at 37$^{\circ}C$, but ALA productivity was lower than at 37$^{\circ}C$. Repeated addition of glycine, succinic acid, and LA increased the production of ALA and the inhibition of intracellular ALA dehydratase activity, with up to 1.3 g/L ALA having been produced in the cultivation.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.944-949
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• 2007

The profiles of on-line sensors such as DO, ORP and pH can provide useful information about pollutant removal reaction in sequencing batch reactor. For detection of denitrification completion, the nitrate hee point from ORP profile has been considered as a main indicator of denitrification completion. However, many researchers pointed out that the nitrate knee usually disappeared been the progress of denitrification is so fast and it makes the fault at detection of denitrification completion. In this paper, dynamic time warping(DTW) method and discriminant analysis were used to detect and isolate the profiles of two cases, denitrification completed and uncompleted. As the results, proposed methods can detect state of denitrification successfully.

• Journal of the Korean Society for Railway
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• v.20 no.2
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• pp.196-202
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• 2017

A very long test track is required for high-speed operation test of the real-scale Linear Synchronous Motor (LSM) for ultra-high-speed trains. The required length results in huge construction cost and economic loss if any error occurs during development. Therefore, validation study of the LSM design technology using a low-cost small-scale model must be carried out in the early research stages. It is possible to deduce an optimal winding method for the armature and determine the mechanical properties of the LSM through a performance tester that applies a rotary-type small-scale LSM model. In addition, it is possible to utilize previous research on LSM control systems. Therefore, a basic design model, comprising a rotary-type LSM tester that meets the requirements for the propulsion of 600km/h-class ultra-high-speed trains, is derived in this study. Finally, an optimal model, which has a stable structure under the condition of 1500rpm or more high-speed rotation, is derived by electromagnetic and mechanical stiffness analysis.