• 전기학회논문지
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• 제63권5호
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• pp.644-651
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• 2014

The renewable energy system and the real-time pricing can provide the significant economic advantage for end-user of residential house. However, according to recent studies, high initial cost of renewable energy system such as photovoltaic (PV) system and lack of suitable load control methods adjusting electric power consumption in response to time-varying price are regarded as the major obstruction for introduction of renewable energy system and real-time pricing in residental household. In this paper, we propose automated optimal load control strategy which aim to achieve not only minimizing the electricity cost but also the increase in the utilization rates of PV generation power of residential PV house in real-time pricing environment. Simulation results show that our proposed optimal load control strategy leads to significant reduction in the electricity costs and increase in the utilization rates of power generated by PV system in comparison with the conventional PV house. Therefore, the proposed optimal load control strategy can provide more economic benefit to end-user.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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• pp.969-973
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• 1987

Ess provides the means to detect, control, and alleviate various system overload conditions. System overload occurs when excessive demands are made on any of the three basic system resources which are hardware, software, and real time. This paper describes the overload control strategy used in No.1A ESS and shows the system status according to traffic load.

• 산업경영시스템학회지
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• 제19권38호
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• pp.77-83
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• 1996

The design of multi -echelon distribution system is need for appropriate inventory control strategy considering for systematic tradeoff between trunk cost in central warehouse and inventory cost in regional warehouse. This study presents a method of the efficient inventory control of multi-echelon distribution system through partial leadtime management.

• 정보통신설비학회논문지
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• 제8권3호
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• pp.122-131
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• 2009

Ubiquitous-Transportation sensor network is able to realize a vehicle ad-hoc network. Since there are some problems in an existing ITS system, the new technology and traffic information strategies are requirements in this advanced system, u-TSN. The purposes of this paper is to introduce the components on u-TSN system, establish new traffic strategies for this system, and then evaluate these strategies by making a comparative study of ITS and using micro traffic simulator, AIMSUN. The strategy evaluated by AIMSUN is position-based multicast strategy which provides traffic information to vehicles using V2I (vehicle to Infrastructure) communication. This paper focuses on the providing real-time route guidance information when congestion is occurred by the incidents. This study estimates total travel time on each route by API modules. Result from simulation experiments suggests that position-based multicast strategy can achieve more optimal network performance and increased driver satisfaction since the total accumulated travel times of both the major road and the total system on position-based multicast strategy are less than those on VMS.

• 설비공학논문집
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• 제20권2호
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• pp.97-105
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• 2008

This paper presents simulated and experimental test results of optimal control algorithm for an encapsulated ice thermal storage system with full capacity chiller operation. The algorithm finds an optimal combination of a chiller and/or a storage tank operation for the minimum total operation cost through a cycle of charging and discharging. Dynamic programming is used to find the optimal control schedule. The conventional control strategy of chiller-priority is the baseline case for comparing with the optimal control strategy through simulation and experimental test. Simulation shows that operating cost for the optimal control with chiller on-off operation is not so different from that with chiller part load capacity control. As a result from the experimental test, the optimal control operation according to the simulated operation schedule showed about 14 % of cost saving compared with the chiller-priority control.

• 제어로봇시스템학회논문지
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• 제7권4호
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• pp.295-303
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• 2001

The demand for steam generators is increasing in industrial systems in which the design strategy should be implemented for safe and efficient operation of steam generators. It is, however, difficult to design a controller by the conventional method because of the nonlinear dynamics of the steam generator and influences by the set value of disturbance. This paper presents an automatic parameter optimization technique for a multivariable fuzzy controller using evolutionary strategy, At first, we use the steady state information such as a steady state gain matrix(SSGM) and a relative gain matrix(RGM). We can obtain much information on the control inputs and the outputs of the boiler-turbine system from the matrices. In order to determine the structure of the controller by using RGM and SSGM, the fuzzy rules are trained by evolutionary strategy. The good performance of the proposed multivariable fuzzy controller is verified through simulations.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.366-373
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• 1998

In this paper, a new control strategy to reduce switching losses in three-phase voltage-source PWM converters is proposed according to Modified-Period-Average-Model (MPAN). The basic concept of this strategy is aimed at calculating the phase control voltages for controlling the source currents to be sinusoidal and in phase with the source voltages, and reducing the number of switching in each period. The phase control voltages of Period-Average-Model(PAM) is obtained according to analyzing the operation of PWM converter. In order to reduce the sensitivity to system parameters in PAM, MPAM is deduced. Then a square wave whose frequency is three times of utility frequency is added to the phase control voltages derived from MPAM. The control strategy reduces the switching losses since there exists about one-third blanking time for every phase in one period. The theoretical derivation and the control strategy are experimentally verified on a 2.5 kW three-phase voltage source converter.

• 전력전자학회논문지
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• 제7권4호
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• pp.384-394
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• 2002

본 논문은 기존의 정전력 제어 대신에 용접품질을 향상시키기 위해 새로운 제어기법을 제안하였다. 제안된 방식을 구현하기 위해 미분기하학 이론을 근거로 한 비선형 피드백 선형화 기법을 이용하여 스폿용접 시스템을 선형시스템으로 한 후 진화전략을 이용하여 PI제어기의 최적 이득을 얻는다. 진화전략은 제어파라미터 최적화 문제를 풀기 위한 방법으로 자연진화의 원리를 모방한 알고리즘이다. 시뮬레이션과 실험결과는 진화전략에 의한 가변전력 제어의 성능이 기존의 제어방법보다 훨씬 더 우수하다는 것을 보여준다.

• 한국항만학회지
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• 제12권2호
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• pp.217-224
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• 1998

During the operation of crane system in container yard, the objective is to transport the load to a goal position as quick as possible without rope oscillation. The container crane is generally operated by an expert operator, but recently an automatic control system with high speed and rapid transportation is required. Therefore, we developed an optimal controller which has to control the crane system with disturbances. In this paper, we present a design of optima 2-DOF PID controller for the control of gantry crane which has to control swing motion and trolley position. We used evolution strategy(ES) to tune the parameters of 2-DOF PID controller. It was compared with general PID controller. The computer simulations show that the proposed method has better performances than the other method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.146-150
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• 1989

In the pole assignment strategy, the closed loop poles are placed at prespecified locations. The amount of control effort required is to some extent proportional to the distance of the proposed closed loop locations of the poles from their open loop locations. The poor choice of closed loop locations may result in Large control effort and it may nuke the system unstable. To overcome this problem, pole shift control strategy is described in this paper. The validity of the proposed control strategy is assured through some simulations.