• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.126-128
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• 1993

Rectifiers of power conversion system are widely used condenser at input to be cheap and to be simple construction. But this method is produced harmonics of pulse at peak value of input AC voltage. The main circuit which make input current of a sinusoidal wave and improve power-factor is almost taken step-up converter. This paper is able to obtain high power-factor and efficiency because the input current is made sinusoidal wave in single phase alternating current(AC) source. Also the proposed converter is able to minimize switching loss by ZVCS(zero voltage switching and zero current switching).

• Journal of Power Electronics
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• 제19권5호
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• pp.1278-1288
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• 2019

A DC-DC Non-Isolated Three-Port Cuk-Cuk (NI-TPCC) converter for interfacing renewable energy sources (RESs) such as Fuel Cell (FC) and Photovoltaic (PV) energy with a DC load is presented in this paper. It features single-stage power conversion from both of the input ports to the load port. The proposed NI-TPCC converter is designed based on the classical Cuk converter. The operational modes and power flow are analyzed in the continuous conduction mode (CCM), and the relationships among the port voltages are derived. Continuous currents in all three ports with less ripple enhance the performance of a fuel cell and its operating life. Furthermore, the output inductor is shared with both of the input ports, which reduces the number of active and passive components. The effectiveness of the designed NI-TPCC converter has been validated through simulation and experimental results.

• 전기전자학회논문지
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• 제11권1호통권20호
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• pp.38-45
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• 2007

A new 8-bit single-slope ADC using analog RAMP generator with digitally controllable dynamic range has been proposed and simulated for column level or per-pixel CMOS image sensor application. The conversion gain of ADC can he controlled easily by using frequency divider with digitally controllable diviber ratio, coarse/fine RAMP with class-AB op-amp, resistor strings, decoder, comparator, and etc. The chip area and power consumption can be decreased by simplified analog circuits and passive components. Proposed frequency divider has been implemented and verified with 0.65um, 2-poly, 2-metal standard CMOS process. And the functional verification has been simulated and accomplished in a 0.35$\mu$m standard CMOS process.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제11B권2호
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• pp.22-27
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• 2001

Salient pole rotor type single phase switched reluctance motor is of simple and rigid structure, short shaft and simple driving circuit. Especially, the output power per unit volume of salient pole rotor structure is comparatively high because the magnetic fluxes of axial and radial direction are simultaneously used. Therefore, this motor will be used at small space and difficult maintenance situations. In this paper, the selecting method of proper pole arc, stator, and rotor dimension of salient pole rotor type single phase SRM is proposed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.356-359
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• 2001

In this paper, the new control algorithm is proposed that compensates instantaneously the active and reactive components of the input currents by the synchronous d,q axis conversion of a single-phase current in controlling the single-phase AC/DC parallel converters for a high speed train. The leakage inductance of a transformer was used as a boost inductance and the ripple of a transformer's primary current was reduced considerably by the parallel operation of the two converters with a proper switching phase-shift. The stable and fast control response characteristic is certificated by a simulation.

• ETRI Journal
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• 제29권4호
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• pp.421-429
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• 2007

This paper presents a direct-conversion CMOS transceiver for fully digital DS-UWB systems. The transceiver includes all of the radio building blocks, such as a T/R switch, a low noise amplifier, an I/Q demodulator, a low pass filter, a variable gain amplifier as a receiver, the same receiver blocks as a transmitter including a phase-locked loop (PLL), and a voltage controlled oscillator (VCO). A single-ended-to-differential converter is implemented in the down-conversion mixer and a differential-to-single-ended converter is implemented in the driver amplifier stage. The chip is fabricated on a 9.0 $mm^2$ die using standard 0.18 ${\mu}m$ CMOS technology and a 64-pin MicroLead Frame package. Experimental results show the total current consumption is 143 mA including the PLL and VCO. The chip has a 3.5 dB receiver gain flatness at the 660 MHz bandwidth. These results indicate that the architecture and circuits are adaptable to the implementation of a wideband, low-power, and high-speed wireless personal area network.

• 한국해양공학회지
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• 제36권1호
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• pp.21-31
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• 2022

In recent years, various studies have been conducted on oscillating-water-column-type wave energy converters (OWC-WECs) with multiple chambers with the objective of efficiently utilizing the limited space of offshore/onshore structures. In this study, a numerical investigation based on a numerical wave tank was conducted on single, dual, and triple OWC chambers to examine the hydrodynamic performances and the energy conversion characteristics of the multiple water columns. The boundary value problem with the Laplace equation was solved by using a numerical wave tank based on a finite element method. The validity of the current numerical method was confirmed by comparing it with the measured data in the previous experimental research. We undertook a series of numerical simulations and observed that the water column motion of sloshing mode in a single chamber can be changed into the piston motion of different phases in multiple OWC chambers. Therefore, the piston motion in the multiple chambers can generate considerable airflow at a specific resonant frequency. In addition, the division of the OWC chamber results in a reduction of the time-dependent variability of the final output power from the device. As a result, the application of the multiple chambers leads to an increase of the energy conversion performance as well as a decrease of the variability of the wave energy converter.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1372-1375
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• 1996

In this paper, we developed and ERMS, which monitors radiation continuously in the vicinity of the nuclear power plant not only to intend health and security of the adjacent residents but also to prevent environmental pollution. Especially, applying digital DCU and SCA which are easy to control and accurate, we obtained good results.

• 한국산업융합학회 논문집
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• 제24권4_1호
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• pp.387-395
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• 2021

Distributed resources such as renewable energy sources and ESS are connected to the low voltage direct current(LVDC) distribution network through the power conversion system(PCS). Control power is required for the operation of the PCS. In general, controller power is supplied from AC power or DC power through switch mode power supply(SMPS). However, the conventional SMPS has a low input voltage, so development and research on high input voltage self-power suitable for LVDC is insufficient. In this paper, to develop Self-Power that can be used for LVDC, the characteristics of the conventional topology are analyzed, and a series-input single-output flyback converter using a flux-sharing transformer for high voltage is designed. The high input voltage Self-Power was designed in the DCM(discontinuous current mode) to reduce the switching loss and solve the problem of current dissipation. In addition, since it operates even at low input voltage, it can be applied to many applications as well as LVDC. The validity of the proposed high input voltage self-power is verified through experiments.

• Journal of Power Electronics
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• 제16권2호
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• pp.654-665
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• 2016

The pumping of electric power from photovoltaic (PV) farms is normally carried out using transformers, which require heavy mounting structures and are thus costly, less efficient, and bulky. Therefore, transformerless schemes are developed for the injection of power into the grid. Compared with the H4 inverter topology, the H6 topology is a better choice for pumping PV power into the grid because of the reduced common mode current. This paper presents how the perturb and observe (P&O) algorithm for maximum power point tracking (MPPT) can be implemented in the H6 inverter topology along with the improved sinusoidal current injected to the grid at unity power factor with the average current mode control technique. On the basis of the P&O MPPT algorithm, a power reference for the present insolation level is first calculated. Maintaining this power reference and referring to the AC sine wave of bus bars, a sinusoidal current at unity power factor is injected to the grid. The proportional integral (PI) controller and fuzzy logic controller (FLC) are designed and implemented. The FLC outperforms the PI controller in terms of conversion efficiency and injected power quality. A simulation in the MATLAB/SIMULINK environment is carried out. An experimental prototype is built to validate the proposed idea. The dynamic and steady-state performances of the FLC controller are found to be better than those of the PI controller. The results are presented in this paper.