• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.738-744
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• 2017

Recently, the installation of energy storage systems (ESSs) has increased in parallel with the extension of renewable energy resources. However, there has been no concrete analysis ofthe performance verification and economic evaluation of ESSs,which makes it difficult to perform aneffective installation and operation of an ESS. In particular, there are no international technical standards and guidelines on electric ESS for frequency regulation applications. Therefore, acomprehensive study on the power quality, impact on grid, extent of contribution, and cost benefit study of ESS are strongly being required. Under these backgrounds, this paper proposes a performance verification algorithm on ESS for frequency regulation application based on ananalysis of the AGC(Automatic Generation Control) performance verification method of PJM in USA. In addition,this paper proposes an economic evaluation algorithm on a 500 MW installation of ESS for frequency regulation applications using the account settlement of an expensive gas-fired generation plant and coal-fired power generation plant. From the simulation with real ESS operation data and 500 MW installation case, it wasconfirmed that the ESS showssuperior performance toany other conventional generators and provides anannual benefit of 500 MW ESS are between 345~429 billon won.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.6
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• pp.29-36
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• 2015

This paper presents an LED backlight driver IC consisting of three linear current regulators and an output-voltage regulation loop with a self-adjustable reference voltage. In the proposed LED driver, the output voltage is controlled by dual feedback loops. The first loop senses and controls the output voltage, and the second loop senses the voltage drop of the linear current regulator and adjusts the reference voltage. With these feedback loops, the voltage drop of the linear current regulator is maintained at a minimum value, at which the driver efficiency is maximized. The output of the driver is a three-channel LED setup with four LEDs in each channel. The luminance is adjusted by the PWM dimming signal. The proposed driver is designed by a $0.35-{\mu}m$ 60-V high-voltage process, resulting in an experimental maximum efficiency of approximately 85%.