• 전기학회논문지
• /
• 제61권5호
• /
• pp.664-668
• /
• 2012

This paper presents the operation strategy of KEPCO(Korea Electric Power COporation) ${\pm}80kV$ 60MW Bipole HVDC system that will be applied between Guemak C/S(converter station) and Hanlim C/S in Jeju island. Unlike intertie HVDC system, this system is located in AC power grid inside. Therefore, the enhancement of system security related with line flow and bus voltages can be major operation strategy. In this paper, in particular, the optimal operation algorithm in the abnormal(not steady state) power system is presented and simulated.

• 지식경영연구
• /
• 제11권5호
• /
• pp.25-36
• /
• 2010

It is widely known that KMS (Knowledge Management System) plays a role of facilitator that contributes to upgrading the organizational performance. Despite this widespread belief, actual operation of KMS has been stalled at the level of being used only for the plain knowledge administration, not reaching the level of utilizing KMS strategically. In this sense, this case study suggests three successful KMS operation strategies-personalization strategy, socialization strategy, and technological strategy. Cases adopted in this study include HIRA(Health Insurance Review & Assessment Service) and KORAIL (Korea Railroad) where KMS has been successfully utilized to improve their organizational innovation and performance as well. Through scrutinizing the two cases, it was concluded that the proposed three KMS operation strategies have potentials of being generally applied to other KMS operation cases.

• 한국항해항만학회지
• /
• 제30권3호
• /
• pp.235-240
• /
• 2006

본 연구에서는 국내에 개발예정인 자동화터미널에 적용가능한 효율적인 ATC 운영로직을 개발하기 위해서 ATC 장비 운영전략을 분석하였다. 그리고, ATC의 효율적인 운영에 있어서 가장 중요한 동적운영로직을 개발하고, 단순한 할당규칙을 수립하여 시뮬레이션 실험으로 로직검증을 하였다. 실험결과 ATC 생산성 저해요인인 간섭을 최소화하는 간섭최소화전략과 능동적인 간섭회피전략이 ATC의 대기시간 및 간섭시간을 감소시키는 것으로 나타났다. 본 연구의 결과로 ATC의 운영효율성을 향상시켜서 자동화터미널의 생산성을 향상시킬 수 있을 것으로 기대된다.

• Journal of Electrical Engineering and Technology
• /
• 제10권2호
• /
• pp.586-594
• /
• 2015

This paper proposes a maximum efficiency operation strategy for three-level T-type inverter in entire operation areas. The three-level T-type inverter has higher and lower efficiency areas compared with two-level inverter. The proposed strategy aims to operate in the maximum efficiency point for the low-voltage and low-power home appliances. The three-level T-type inverter is analyzed in detail, and the two operation mode selection strategy is developed. The proposed algorithm is verified by theoretical analysis and experimental results.

• 한국지열·수열에너지학회논문집
• /
• 제14권1호
• /
• pp.16-21
• /
• 2018

This work aims to develop a platform to investigate the effect of operation schedules on the building energy consumption and to derive a simulation model based optimal start and stop daily strategy. An open-source building energy simulation tool DOE2 is used for the engine, and the developed simulation model is validated using ASHRAE guideline 14. The effect of late-start/early-stop operation of HVAC system on the daily building energy consumption was analyzed using the developed simulation model. It was found that about 10% of energy consumption cut was possible using the control strategy for an hour of advance of the stop operation, and about 3% per an hour of delay of the start operation.

• International Journal of Automotive Technology
• /
• 제6권5호
• /
• pp.529-536
• /
• 2005

This paper presents a novel design of a fuzzy control strategy (FCS) based on torque distribution for parallel hybrid electric vehicles (HEVs). An empirical load-regulating vehicle operation strategy is developed on the basis of analysis of the components efficiency map data and the overall energy conversion efficiency. The aim of the strategy is to optimize the fuel economy and balance the battery state-of-charge (SOC), while satisfying the vehicle performance and drivability requirements. In order to accomplish this strategy, a fuzzy inference engine with a rule-base extracted from the empirical strategy is designed, which works as the kernel of a fuzzy torque distribution controller to determine the optimal distribution of the driver torque request between the engine and the motor. Simulation results reveal that compared with the conventional strategy which uses precise threshold parameters the proposed FCS improves fuel economy as well as maintains better battery SOC within its operation range.

• Journal of Power Electronics
• /
• 제18권5호
• /
• pp.1545-1554
• /
• 2018

This paper proposes a modified control strategy to improve the performance of three-phase four-leg shunt active power filters (APFs) for the compensation of three phase unbalanced loads. Unbalanced current cannot be obtained accurately by a harmonic detector due to the lower frequency. The proposed control strategy eliminates conventional harmonic detectors by directly regulating the source current. Therefore, the computational complexity is greatly reduced and the performance of the APF is improved. A mathematic model has been developed based on the source currents. The corresponding controllers have been designed based on the sinusoidal internal model principle. The proposed control strategy can guarantee excellent compensation performance and stable operation after an extreme disturbance such as a short circuit fault. In addition, the proposed technique can selectively compensate specific harmonics. A 50kVA prototype APF is implemented in the laboratory to validate the feasibility and performance of the proposed control strategy.

• 한국항만학회지
• /
• 제13권2호
• /
• pp.323-332
• /
• 1999

The bus should supply an equal service to the whole community as feeder trip. However the existing bus route can not supply an effective feeder service in spite of the changes in the latent demand by the variety of regional structural change. This study aimed to establish the concept which frames the bus operation and management to cope with the latent demand to the bus. This study tackled this evidence by analyzing the transportation problems in terms of the urban growth emphasizing the following issues ; First, the strategy to improve the bus operation Second the land use control appropriate for the public transportation network Third economical range to justify the bus operation Second, the land use control appropriate for the public transportation network Third, economical range to justify the bus operation Fourth, the allowance for the private transportation mode On the latter part, the difference on the bus operation was compared to determine the range within which the bus operation could be justified. This study would provide some implications to improve the management for bus operation and fundamental information to develop the bus operation system.

• 전력전자학회논문지
• /
• 제9권4호
• /
• pp.341-349
• /
• 2004

본 논문에서는 전체 시스템의 용량 증대와 부하 중요도에 따른 신뢰성 향상을 위해 사용되는 UPS 병렬 운전시 발생하는 문제점을 해석하고, 이를 해결하기 위해 기존에 연구되어온 다양한 제어기법들을 조사하였다. 또한 기존의 연구방법에서 적용할 수 없었던 다른 정격의 병력 운전 적용시 L, C 출력필터에 의한 문제점을 해결하기 위해 주종 제어를 이용한 3상 UPS의 전류 분달 제어기법이 연구되었다. 제안된 제어 알고리즘의 타당성을 검증하기 위해 시뮬레이션 및 실험을 수행하였다.

• 한국정밀공학회지
• /
• 제30권11호
• /
• pp.1153-1160
• /
• 2013

SMISMO valve configuration is now starting to draw attention of the researchers of the construction equipment industry to increase the fuel efficiency of their equipment like excavators and wheel-loaders. An open-loop control strategy for grading operation of hydraulic excavator systems using SMISMO valve configuration is investigated in this paper. Tabor's algorithm for 1 d.o.f. SMISMO system under the assumption of quasi-static operation is revealed as not adequate for multi d.o.f. system with large moment of inertia even though the motion of the system is slow. New parameters are proposed in this paper. It modifies Tabor's open-loop control strategy for the grading operation of hydraulic excavators using SMISMO valve configuration. A simulation-based parameter tuning method is also proposed. It uses GA (Genetic Algorithm) to find the best parameter values. Simulation study for a practical hydraulic excavator shows the validity of the proposed open-loop control strategy.