• Journal of Power Electronics
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• v.12 no.3
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• pp.487-494
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• 2012

A new low cost high power density photovoltaic power conditioning system (PV PCS) with an energy storage system is proposed in this paper. Its high power density and cost effectiveness can be achieved through the unification of the maximum power point tracker and the battery charger/discharger. Despite the reduced power stage, the proposed system can achieve the same performance in terms of maximum power point tracking and battery charging/discharging as the conventional system. When a utility power failure happens, the proposed system cannot perform maximum power point tracking at the UPS mode. However, the predetermined battery voltage near the maximum power point of the PV array can effectively generate a reasonable PV power even at the UPS mode. Therefore, it features a simpler structure, less mass, lower cost, and fewer devices. Finally, to confirm the operation, validity, and features of the proposed system, a theoretical analysis and experimental results from a single phase AC 220Vrms/1.5kW prototype are presented.

• Communications for Statistical Applications and Methods
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• v.20 no.4
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• pp.311-319
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• 2013

Cooray and Ananda (2005) proposed a composite lognormal-Pareto model to analyze loss payment data in the actuarial and insurance industries. Their model is based on a lognormal density up to an unknown threshold value and a two-parameter Pareto density. In this paper, we implement the minimum density power divergence estimation for the composite lognormal-Pareto density. We compare the performances of the minimum density power divergence estimator (MDPDE) and the maximum likelihood estimator (MLE) by simulations and an example. The minimum density power divergence estimator performs reasonably well against various violations in the distribution. The minimum density power divergence estimator better fits small observations and better resists against extraordinary large observations than the maximum likelihood estimator.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.883-888
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• 2012

Anode electrode is one of the most important factors in microbial fuel cell (MFC). This study was conducted to investigate the effects of mediator as methylene blue (MB) and electrode surface area on the power density of MFC with sponge and carbon nano tube (CNT) electrode (SC). The SC electrode with MB (MC) showed the maximum power density increased from 74.0 $mW/m^2$ to 143.1 $mW/m^2$. The grid shaped sponge and CNT (GSC) electrode showed the maximum power density of 209.2 $mW/m^2$ due to the increase of surface area from 88.0 to 152.0 $cm^2$. The GSC electrode with MB (GMC) revealed the maximum power density of 384.9 $mW/m^2$ which was 5.2 times higher than that obtained from the MFC with SC. Therefore MB and increase of surface area led to enhance the performance of microbial fuel cell such as power density.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.4
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• pp.503-509
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• 2013

Electrochemical redox capacity of a microbial fuel cell (MFC) electrode is an important factor in the power density. This study was conducted to investigate the redox capacity of surface modified anode and cathode electrodes by measuring their conductivities. An anode electrode was modified with nitric acid and a cathode electrode was modified with heat treatment. The anode electrode modified with 20 % of the nitric acid concentration showed the highest conductivity of $6.2{\mu}S/cm/g$ and the maximum power density of $306.0mW/m^2$ when used in a MFC. The cathode electrode modified at $472^{\circ}C$ for 18 min showed the highest conductivity of $5.2{\mu}S/cm/g$ and the maximum power density of $276.20mW/m^2$ when used in a MFC. On the other hand, an MFC using both the electrodes showed the highest maximum power density of $408.2mW/m^2$. Meanwhile, a control MFC without modified electrodes generated very small voltage (0.014 mV), so the power density could not be measured.

• Journal of Electrochemical Science and Technology
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• v.12 no.1
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• pp.38-57
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• 2021

The different weight ratios of Pd to Pt, i.e., 16:4, 10:10, 4:16 in Pd-Pt/C and Pd (20 wt. %) /C electrocatalysts with low metal loading were synthesized for glycerol electrooxidation in an air breathing microfluidic fuel cell (MFC). The cell performance on Pd-Pt (16:4)/C anode electrocatalyst was found best among all the electrocatalysts tested. The single cell when tested at a temperature of 35℃ using Pd-Pt (16:4)/C, showed maximum open circuit voltage (OCV) of 0.70 V and maximum power density of 2.77 mW/㎠ at a current density of 7.71 mA/㎠. The power density increased 1.45 times when cell temperature was raised from 35℃ to 75℃. The maximum OCV of 0.78 V and the maximum power density of 4.03 mW/㎠ at a current density of 10.47 mA/㎠ were observed at the temperature of 75℃. The results of CV substantiate the single cell performance for various operating parameters.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.7
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• pp.430-436
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• 2004

This paper presents an advanced control technique for power density maximization of the Brushless DC (BLDC) generator by using the linear tracking method. In a generator of given rating, the weight and size of the system affect the fuel consumption directly. Therefore, power density is one of the most important issues in a stand-alone generator. BLDC generator has high power density in the machine point of view and additional increases of power density by control means can be expected. Conventional rectification methods cannot achieve the maximum power possible because of hon-optimal current waveforms. The optimal current waveform to maximize power density and minimize machine size and weight in a nonsinusoidal power supply system has been derived, incorporated in a control system, and verified by simulation and experimental work. A new simple algebraic method has been proposed to accomplish the proposed control without an FFT which is time consuming and complicated.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.2
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• pp.39-52
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• 2003

This paper deals with an automatic design procedure for the maximum torque density and power factor in a synchronous reluctance motor (SynRM). The focus of this paper is the design relative to the number of flux barrier and the ratio Kw of flux barrier width to iron sheet width of a SynRM under the mechanical constraint. The Finite Elements Analysis (FEA) has been used to evaluate the maximum torque density and power factor with each rotor shape. The proposed procedure allows to define the rotor geometric dimensions starling from an existing mootor or a preliminary design. The maximum torque density and power factor of a SynRM has been resulted with the rotor design variation. To prove the propriety of the designed SynRM, the Digital Signal Processor (DSP) installed experimental devices are equipped and the efficiency characteristic test is Performed.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.295-298
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• 1999

AlGaAs/InGaAs power P-HEMTS (Pseudo-morphic High Electron Mobility Transistors) with 1.0-${\mu}{\textrm}{m}$ gate length for PCS applications have been fabricated. We adopted single heterojunction P-HEMT structure with two Si-delta doped layer to obtain higher current density. It exhibits a maximum current density of 512㎃/mm, an extrinsic transconductance of 259mS/mm, and a gate to drain breakdown voltage of 12.0V, respectively. The device exhibits a power density of 657㎽/mm, a maximum power added efficiency of 42.1%, a linear power gain of 9.85㏈ respectively at a drain bias of 6.0V, gate bias of 0.6V and an operation frequency of 1.765㎓.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.513-518
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• 2015

Salinity gradient power (SGP) has attracted significant attention because of its high potential. In this study, we evaluate reverse electrodialysis (RED) with various compositions of available resources. The polarization curve (I-V characteristics) shows linear behavior, and therefore the power density curve has a parabolic shape. We measure the power density with varying compartment thicknesses and inlet flow rates. The gross power density increases with decreasing compartment thickness and increasing flow rate. The net power density, which is the gross power density minus the pumping power, has a maximum value at a compartment thickness of 0.2 mm and an inlet flow rate of 22.5 mL/min. The power density in RED is also evaluated with compositions of desalination brines, seawater, river water, wastewater, and brackish water. A maximum power density of $1.75W/m^2$ is obtained when brine discharged from forward osmosis (FO) and river water are used as the concentrated and the diluted solutions, respectively.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.9
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• pp.468-474
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• 2003

This paper describes the development of an open frame type high power density switching converter. It is based on the active clamp forward converter with synchronous rectifier, and packaged by using the open frame and multi-layer printed circuit board (PCB) technology to achieve the higher power density. Furthermore, the windings of transformer and inductor are also realized by multi-layer PCB so that it also contributes to achieve higher power density. Through the experiment on the prototype converter of 50[W], it is confirmed that power density of 50[W/i$n_3$] and maximum efficiency of over 91[%] are obtained.