• Journal of Digital Convergence
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• v.11 no.12
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• pp.401-406
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• 2013

In this paper, the optimum transmission method is proposed to save the energy and to increase the throughput of the adaptive modulation mobile radio system with frame length control. Traditionally, adaptive modulation has been used to improve the throughput using the power margin of the system design. Considering the frame length vs energy saving and adaptive modulation, the optimum transmission method is proposed for hub and mobile station each.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.133-136
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• 2005

Recently, a drain of energy resources is issued seriously. The daylight responsive dimming systems can reduce electric energy uses. But, we cannot predict amounts of energy-saving and accuracy of system performance. Therefore, the purpose of this study is a development of software for the system performance of daylight responsive dimming systems. The principle of this software based on luminous flux transfer method and finite elements method. The control algorithm of this software and daylight responsive dimming systems use the same algorithm. In addition the advantages of this software are use to same algorithm of daylight responsive dimming systems, electric power-luminous flux data and rates of frequency of sky conditions. Therefore, this software can predict more correct calculation about illuminance and amounts of energy-saving of daylight responsive dimming systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.285-289
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• 2020

The configuration of hierarchical wireless networks is provided to support diverse network environments. In the base station, two system state can be basically considered for the operation management so that the state transition may be occurred between active and sleep modes. Hence, to reduce energy consumption the system operation management of the low power should be considered to the base station system. In this paper we consider the analytical model of Discontinuous Reception (DRX) to investigate the system management. We provide the analysis scheme of base station system by the DRX model, and the low power factor would be investigated for the energy consumption. We also use the finite-state Markov system model that in a system state period the wireless resource request and the operation of service call arrival interval is considered to numerically analyze the performance of energy saving operations of base station.

• Journal of Hydrogen and New Energy
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• v.34 no.2
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• pp.187-195
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• 2023

Data centers not only consume significant electricity to operate IT equipment, but also use a lot of electricity to cool the heat generated by IT equipment. The waste heat of a high-temperature polymer electrolyte fuel cell (HT-PEFC) is capable of producing cooling , so it can be effectively applied to data centers that require cooling throughout the year. The energy-saving effects of the proposed combined cooling, heat and power (CCHP) system using HT-PEFC. That was analyzed based on the annual energy consumption data of a specific data center. When the system was running at 100% of the year, It was shown that the installation of 1 MW of the proposed system can save 3,407 MWh of electrical energy per year. In addition, compared to the existing system, the annual power usage effectiveness can be improved from 2.0 to 1.57 and 6,293 MWh of extra heat energy per year can be produced to sell. Furthermore, sensitivity analysis was performed on the fuel cell operating temperature and current density to guide the appropriate installation capacity of the proposed system.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.488-490
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• 2001

A dispered power system means a little bit of small power generation equipment located near the power-damend areas. Due to no power supply line, such a power source is very favorable for the decrease in loss of electric power supply, in comparison to the giantly focused power source, Because of small power source, this power source also corresponds promptly to the variation of power demend. On the basis of energy saving, environmental reservation, and utilization of natural or unused energy, solar power plants can be introduced into the residence section of cities and small water or wind-power plants near the urban areas. In case of Korea, some wind farm have been introduced into Cheju island, Condensed introduction of several small power sources into an used distribution line may, however, result in a big problem, it is, therefore, necessary that protective-cooporative plans between power quality and distribution line should be introduced for efficient utilization of KEPCO distribution system.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.4
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• pp.382-391
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• 2005

Increasing of the nonlinear type power electronics equipment, power conditioning systems (PCS) have been researched and developed for many years in order to compensate for harmonic disturbances and reactive power. PCS's not only improve harmonic current and power factor in the ac grid line but also achieves energy saving used by the renewable energy source (RES). In this paper, the implementation of a current controlled voltage source inverter (CCVSI) using RES for PCS is presented. The basic principle and control algorithm is theoretically analyzed and the design methodology of the system is discussed. The proposed system could achieve power quality control (PQC) to reduce harmonic current and improve power factor, and demand side management (DSM) to supply active power simultaneously, which are both operated by the polarized ramp time (PRT) current control algorithm and the grid-interactive current control algorithm. A 1KVA test model of the CCVSI has been built using IGBT controlled by a digital signal processor (DSP). To verify the proposed system, a comprehensive evaluation with theoretical analysis, simulation and experimental results is presented.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.505-510
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• 2009

In this paper, building energy analysis and energy cost of power stand up and demand control over the power proposed to reduce power demand. Through analysis of the load power demand special day were able to apply the pattern. In addition, the existing rate of change of load forecasting to reduce the large errors were not previously available data. And daily schedules and special day for considering the exponential smoothing methods were used. Previous year's special day and the previous day due to the uncertainty of the load and the model components were considered. The maximum demand power control simulation using the fuzzy control of power does not exceed the contract. Through simulation, the benefits of the proposed energy-saving techniques were demonstrated.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1079-1080
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• 2006

This paper presents the methods to save energy by using load consumption pattern analysis. Base on the substation annual power usage data, the characteristic of the substation power consumption have investigated. With this investigation effective electrical billing condition and the control target load has been determined. Most of power usage comes from the motor car, so power system and load table of motor car were reviewed. And in the metropolitan area the peak power consumption occurs at summer or winter rush hours because of its typical characteristics. From this data control point of time are determined. Through the whole study the methode to control the power Peak consumption are proposed and prototype was designed.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.307-311
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• 2004

In this study, a novel hybrid vehicle is proposed. The vehicle has a flywheel-engine hybrid system. Flywheels are more effective as energy charge systems than electric batteries in a respect of output power density. However, transmissions to effectively drive flywheels are very complex systems such as CVTs (Continuously Variable Transmissions). In the proposed hybrid vehicle, Constant Pressure System is employed, which is hydraulic power transmission. Using Constant Pressure Systems, hydraulic CVTs are easily realized with variable displacement pumps/motors. In this paper, firstly, the proposed flywheel hybrid vehicle making use of Constant Pressure System is described. Secondly, fuel consumption characteristics of the flywheel hybrid vehicle are experimentally examined with the stationary test facility, which employs a flywheel as a load emulating vehicle inertia. Finally, the experimental results and discussions are described. Fuel consumption of 26km/L is expected for 10 mode driving schedule with vehicle mass of 1500kg.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.657-661
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• 2001

In This paper describes on the development of detecting power using Microprocessor. The detecting power system is composed of main controller system and analyzing software. Re system detected voltage, current, temperature, leakage current md its saved in ROM. This system applies the 'AT89C52' to CPU and 'AM29F040B' used a memory to sue the data.