• Title/Summary/Keyword: Optimal charge and discharge

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A Study on Adaptive Operation Control to Stabilize bus Voltage of GEO Satellite Power Supply Module (정지궤도 위성용 전력공급 모듈의 버스 전압 안정화를 위한 최적동작 제어에 관한 연구)

  • Ahn, Tae-Young;Choe, Hyun-Su
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.2
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    • pp.123-129
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    • 2016
  • In this paper, results of produced PCU(Power Control Unit) prototype was showed by suggesting and maintaining optimal operation status which let the three functional modules automatically operate with its necessity by prioritizing operation process. In order to validate effectiveness of the suggested method, we produced a test PCU and examined the results. PCU consists of S3R(Sequential Switching Shunt Regulator), BCR(Battery Charge Regulator), and BDR(Battery Discharge Regulator): converting photovoltaic power into constant voltage at linked bus voltage; storing dump power in the battery which is an auxiliary energy storage device; and supplying power charged in battery to the load. To maintain its high reliability and optimal condition of these three power conversion modules, each module operates in parallel and stable bus voltage is required to be retained at all-time due to the nature of power supply for satellite.

Development of Dynamic Voltage Restorer System Considering Characteristics of EDLC (EDLC의 특성을 고려한 동적전압보상시스템의 개발)

  • Lee, Sang-Cheol;Seo, Il-Dong
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.3
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    • pp.288-292
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    • 2010
  • Recently, in energy storage system, the EDLC is paid attention as a new environmentally friendly energy storage element. This capacitor has higher energy density than the electrolytic capacitor. Also, this capacitor has a lot of advantage such as no maintenance, longer life cycle and faster charge-discharge time than the battery system. But the EDLC must have a each charge-discharge controller to effectively control, an energy design method circuit to use effectively energy, and several compensation techniques to control a optimal operating. In this respect, this study suggests major parameters to effectively represent the characteristics of EDLC, the measurement methods of those parameters have been investigated with experiments, and the interpretation about the buck/boost DC/DC converter for the operation of EDLC.

A Study on Optimal Operation of Cooling System Using Dynamic Programing (동적 계획법을 이용한 냉방시스템 최적운전에 관한 연구)

  • Han, Kyu-Hyun;Yoo, Seong-Yeon;Lee, Je-Myo;Lee, Il-Su
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.1061-1064
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    • 2009
  • The objective of this study is to find the optimal operational planning of the hybrid cooling system, which is combined by ice storage system and the absorption chiller. The optimization technique used in this study is dynamic programming. The objective function is summed cost during a day including charge and discharge periods of ice storage system and operation time of absorption chiller. Assuming that initially ice storage tank is stored fully and the cooling load is perfectly predicted for the operational planning. This method provides the most efficient and economic combination of equipment operational planning for cooling with respect to energy consumption cost.

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Influence of Urea Precursor on the Electrochemical Properties of Ni-Co-based Metal Organic Framework Electrodes for Supercapacitors

  • Jung, Ye Seul;Jung, Yongju;Kim, Seok
    • Applied Chemistry for Engineering
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    • v.33 no.5
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    • pp.523-531
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    • 2022
  • A NiCo-metal organic framework (MOF) electrode, prepared using urea as a surfactant, was synthesized using a one-pot hydrothermal method. The addition of urea to the NiCo-MOF creates interstitial voids and an ultra-thin nanostructure in the NiCo-MOF, which improves its charge transfer performance. We obtained the optimal metal to surfactant ratio to achieve the best specific capacitance. The NiCo-MOF was employed as the working electrode material in a three-electrode system. Field emission scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy were employed to characterize the microstructures and morphologies of the composites. Cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy curves were employed to quantify the electrochemical properties of the electrodes in a 6 M KOH electrolyte.

Preparation of Expanded Graphite using Perchloric Acid and It's Application as Anode Materials for High Power Li-ion Secondary Battery (과염소산을 이용한 팽창흑연의 제조 및 고출력 리튬이온전지 음극재로의 응용)

  • Park, Yul-Seok;Zheng, Hua;Kim, Myung-Soo
    • Journal of the Korean Applied Science and Technology
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    • v.28 no.1
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    • pp.85-94
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    • 2011
  • Expanded graphites were used as anode materials of high power Li-ion secondary battery. The expanded graphite was prepared by mixing the graphite with $HClO_4$ as a intercalation agents and $KMnO_4$ as a oxidizing agents. The physical and electrochemical properties of prepared expanded graphites through the variation of process variables such as contents of intercalation agent and oxidizing agent, and heat treatment temperature were analyzed for determination of optimal conditions as the anode of high power Li-ion secondary battery. After examing the electrochemical properties of expanded graphites at the different preparing conditions, the optimal conditions of expanded graphite were selected as 8 wt.% of oxidizing agent, 400 g of intercalation agent for 20 g of natural graphite, and heat treatment at $1000^{\circ}C$. The sample showed the improved charge/discharge characteristics such as 432 mAh/g of initial reversible capacity, 88% of discharge rate capability at 10 C-rate, and 24 mAh/g of charge capacity at 10 C-rate. However, the expanded graphite had the problems of potential plateaus like natural graphite and lower initial efficiency than the natural graphite.

An Analysis of Optimal Operation Strategy of ESS to Minimize Electricity Charge Using Octave (Octave를 이용한 전기 요금 최소화를 위한 ESS 운전 전략 최적화 방법에 대한 분석)

  • Gong, Eun Kyoung;Sohn, Jin-Man
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.4
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    • pp.85-92
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    • 2018
  • Reductions of the electricity charge are achieved by demand management of the load. The demand management method of the load using ESS involves peak shifting, which shifts from a high demand time to low demand time. By shifting the load, the peak load can be lowered and the energy charge can be saved. Electricity charges consist of the energy charge and the basic charge per contracted capacity. The energy charge and peak load are minimized by Linear Programming (LP) and Quadratic Programming (QP), respectively. On the other hand, each optimization method has its advantages and disadvantages. First, the LP cannot separate the efficiency of the ESS. To solve these problems, the charge and discharge efficiency of the ESS was separated by Mixed Integer Linear Programming (MILP). Nevertheless, both methods have the disadvantages that they must assume the reduction ratio of peak load. Therefore, QP was used to solve this problem. The next step was to optimize the formula combination of QP and LP to minimize the electricity charge. On the other hand, these two methods have disadvantages in that the charge and discharge efficiency of the ESS cannot be separated. This paper proposes an optimization method according to the situation by analyzing quantitatively the advantages and disadvantages of each optimization method.

Development of Blade on 9㎥ Class of Mixer Drum (9㎥급 믹서드럼 블레이드의 개발)

  • Shin, H.G.;Choi, H.C.;Bean, D.H.;Kim, Y.C.
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.3
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    • pp.65-71
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    • 2011
  • The concrete mixer truck which is in charge of raw materials in civil engineering construction of the concrete loading, transport, placement, is used $6m^3$, $7m^3$ class in domestic(Korea). But in the case of the international construction fields are utilized $9m^3$ or above class because of the large-scale engineering and construction circumstances. In this paper, to develop a large $9m^3$ class mixer drum and the mixer drum in order to complement the technical and discharge that is responsible for stirring the blades by applying optimal design through implementation of the optimal shape of the concrete in the drum maintenance and placement of high-quality effects on increasing discharge such as advanced conventional drum mixer is to secure and differentiated technology. Large, heavy weight in development and uphold the drum mixer vehicle sub-frame is required to settle the design of the existing class mixer drum frames per $6m^3$ changed to account for changes in slope and length using CATIA V5 3D modeling work was performed.

Battery Discharge System Configuration using Photovoltaic Simulator and PCS (태양광 시뮬레이터와 PCS를 이용한 배터리 방전시스템 구성)

  • Jeong, Da-Woom;Park, Sung-Min;Park, Seong-Mi;Park, Sung-Jun;Moon, Seung-Pil
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.3
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    • pp.491-498
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    • 2020
  • Recently, In the production line of batteries, charge and discharge tests are essential to verify battery characteristics. In this case, the battery charging uses a unidirectional AC/DC converter capable of output voltage and current control, and the discharge uses a resistive load. Since this method consumes energy during discharge, it must be replaced with a bi-directional AC/DC converter system capable of charging and discharging. Although it is difficult to replace the connected inverter part of the bi-directional AC/DC converter system due to the high cost, the spread of the solar-connected inverter rapidly increases as the current solar supply business is activated, and thereby the solar-connected type Inverter prices are plunging. If it can be used as a power converter for battery discharge without program modification of the solar-powered inverter, it will have competition. In this paper, propose a new battery discharge system using a combination of a photovoltaic DC/DC simulator and photovoltaic PCS using a battery to be used as a power converter for battery discharge without program modification of a low-cost photovoltaic inverter. In addition, propose an optimal solar characteristic curve for the stable operation of PCS. The validity of the proposed system was verified using a 500[W] class solar DC/DC simulator and a solar PCS prototype.

A Study on the Optimal Operation According to Appropriate PCS and Battery Capacity Estimation of PV-BESS System (PV-BESS 시스템의 적정 PCS, 배터리용량 산정에 따른 최적 운영에 관한 연구)

  • Choi, Yun Suk;Na, Seung You
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.9
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    • pp.1174-1180
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    • 2018
  • In December 2017, the government announced plans to increase the current proportion of renewable energy from 7% to 20% by 2030 through a plan called the Renewable Energy 3020 Implementation Plan. Therefore, the demand for installation of photovoltaic(PV), wind turbine(WT) and battery energy storage system(BESS) is expected to increase. In particular, the system combined with energy storage system(ESS) is expected to take up a large portion since PV and WT can receive high renewable energy certificates(REC) weights when combined with ESS. In this study, we calculate the optimal capacity of the power conditioning system(PCS) and the BESS by comparing the economical efficiency and maximize the efficiency of the PV-BESS system in which the PV and the BESS are connected. By analyzing the system marginal price(SMP) and REC, it maximize profits through application of REC weight 5.0 and optimal charge-discharge scheduling according to the SMP changes.

A Study on the Magnetic Field Analysis and Optimal Core Design of DC Current Sensor for Vehicles (자동차용 DC Current Sensor의 자장해석 및 코어 최적형상 설계에 관한 연구)

  • Lee, Hee-Sung;Park, Jong-Min;Kim, Choon-Sik;Kim, Sung-Gaun
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.5
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    • pp.74-83
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    • 2009
  • Recently, usage of electric and electronic system for car increases rapidly. Consequently power monitoring supplied to the system is essential for management and controlling. Generally, battery status is monitored through measuring and diagnosing the current measurement method utilizing Hall Effect. Therefore, in this paper, we analysed magnetic field to develop the solution of DC current sensor using Hall Effect which is the core of design and development. By analysing the magnetic field by FEM using Maxwell 3D software, the location of the highest output current and stable part in the Hall IC sensor was shown. Also, the optimal core design of DC current sensor using parametric and Simplex method was presented. A car battery charge and discharge process dependant on time effect on the changing of magnetic field was simulated and compared to the result from the experiment result of actual vehicle.