• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.10-10
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• 2009

Transparent BNO thin films were grown on Al-doped ZnO (AZO)/Ag/AZO/polyethersulfon (PES) (abbreviated as AAAP) transparent electrodes at a low temperature by the NCD technique. The BNO films grown on the crystallized AZO/Ag/AZO (AAA) electrodes exhibit an amorphous phase with a root mean square (rms) roughness of approximately 2 nm in the range of deposition temperature. The capacitors (Pt/BNO/AAAP) with BNO films grown at $100^{\circ}C$ show a dielectric constant of 24 and dissipation factor of 8% at 100 kHz, a leakage current density of about $8{\times}10^{-6}A/cm^2$ at an applied voltage of 1.0V. The optical transmittances of the BNO/AAAP exhibited above 80% at wavelength of 550nm at all of deposition temperature. The mechanical stability of the BNO/AAA as well as AAA electrode with the PES substrates through the bending was ensured for flexible electronic device applications. The transparent BNO capacitors grown on AAAP are powerful candidate for integration with the transparent solar cells.

• The Journal of the Acoustical Society of Korea
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• v.42 no.1
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• pp.57-66
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• 2023

In this paper, it was investigated how the amount of energy harvesting will be varied from the FTEH which has inlet area is wider than outer area and attaching cantilever type MFC (Macro Fiber Composite) using by theoretical and experimental approaches. When MFC length increased 50 % vibration displacement also increased 3.5 times. When thickness decreased vibration displacement increased 30.9 times. In underwater tank experiments FTEH with spiral screw, flexible support, vertical direction fabrication cases showed maximum energy harvesting more 5 times than the case of MFC installed horizontally without spiral screws and on rigid supports. When the flow speed of 0.24 m/s FTEH's optimal resistance applied 4,10 kΩ, energy storage in the capacitor was measured 4 ㎼·s during 350 seconds. It was confirmed that the charging energy can be increased by lengthening the capacitor charging time of the large-area MFC installed vertically on the flexible support at high flow speed.

• ETRI Journal
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• v.31 no.6
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• pp.717-724
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• 2009

This paper describes a 1.2 V 12 b 60 MS/s CMOS analog front-end (AFE) employing low-power and flexible design techniques for image signal processing. An op-amp preset technique and programmable capacitor array scheme are used in a variable gain amplifier to reduce the power consumption with a small area of the AFE. A pipelined analog-to-digital converter with variable resolution and a clock detector provide operation flexibility with regard to resolution and speed. The AFE is fabricated in a 0.13 ${\mu}m$ CMOS process and shows a gain error of 0.68 LSB with 0.0352 dB gain steps and a differential/integral nonlinearity of 0.64/1.58 LSB. The signal-to-noise ratio of the AFE is 59.7 dB at a 60 MHz sampling frequency. The AFE occupies 1.73 $mm^2$ and dissipates 64 mW from a 1.2 V supply. Also, the performance of the proposed AFE is demonstrated by an implementation of an image signal processing platform for digital camcorders.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.51-52
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• 2014

전력계통은 전력수요의 지속적인 성장에 따라서 전력설비의 추가를 지속적으로 추진하고 있지만, 심해지는 환경문제 등으로 인해 용지 확보에 어려움이 있다. 이로 인해 송전선로 장거리화, 용량부족량 등 전력계통에 여러 가지 복잡한 문제가 야기되는데, 이것은 곧 전력계통의 안정도와 직결된다. 이러한 문제를 효과적이면서 경제적인 해결방법으로 FACT(Flexible AC Transmission System)기술이 주목 받고 있다. FACTS 기기 중 SVC(Static Var Compensator)는 상용운전 중이며, 기존 동기조상기에 비해 저렴하고, 신속 정확한 전압제어를 하는 장점이 있다. SVC는 TCR(Thyristor Controlled Reactor)과 TSC(Thyristor Switched Capacitor), FC(Fixed Capacitor)등 여러 종류의 구성을 가질 수 있다. TCR과 TSC는 실제 운전에 앞서 여러 가지 방법으로 검증이 필요하다. 합성 시험회로 설비(Synthetic Test Circuit)는 TCR과 TSC 안에 존재하는 Thyristor Valve의 동작을 실제 동작 조건으로 동작시켜, 동작의 신뢰성을 검증하는 설비이다. 본 논문에서는 TCR의 Operational Test를 위한 STC를 기술하고 있다. 설계된 STC는 PSCAD를 사용하여 검증하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.1
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• pp.21-28
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• 2012

In this paper, we propose a flexible zeroth-order resonant(ZOR) antenna. Its zero phase constant ensures that the antenna performance is independent of substrate deformation. A composite right/left-handed transmission line is designed based on coplanar waveguide technology to realize the zeroth-order resonance phenomenon. The CRLH is an implementation of metamaterial(left handed material) which is composed of shunt inductance and series capacitance. In order to yield additional circuital parameter, chip inductor and gap capacitor is added, respectively. The proposed ZOR antenna provides good performances: reasonable bandwidth(6.5 %) and peak gain(0.69~1.39 dBi). Simulated and measured results show that the antenna's resonant frequencies and radiation patterns are almost unchanged at different curvature diameters of 30, 50, 70 mm, as well as for a flat surface.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1587-1599
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• 2017

This paper proposes a real-time implementation of an optimal operation of a double stage grid connected wind power system incorporating an active power filter (APF). The system is used to supply the nonlinear loads with harmonics and reactive power compensation. On the generator side, a new adaptive neuro fuzzy inference system (ANFIS) based maximum power point tracking (MPPT) control is proposed to track the maximum wind power point regardless of wind speed fluctuations. Whereas on the grid side, a modified predictive current control (PCC) algorithm is used to control the APF, and allow to ensure both compensating harmonic currents and injecting the generated power into the grid. Also a type 2 fuzzy logic controller is used to control the DC-link capacitor in order to improve the dynamic response of the APF, and to ensure a well-smoothed DC-Link capacitor voltage. The gained benefits from these proposed control algorithms are the main contribution in this work. The proposed control scheme is implemented on a small-scale wind energy conversion system (WECS) controlled by a dSPACE 1104 card. Experimental results show that the proposed T2FLC maintains the DC-Link capacitor voltage within the limit for injecting the power into the grid. In addition, the PCC of the APF guarantees a flexible settlement of real power exchanges from the WECS to the grid with a high power factor operation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.5
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• pp.387-391
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• 2012

Graphene was fabricated onto Ni/Si substrate using a rapid-thermal pulse CVD and they were transferred onto the Ti/PES flexible substrate. For top electrode applications of the BMNO dielectric films, graphene was patterned using a argon plasma. Through an AFM image and a leakage current density of the BMNO films grown onto various bottom electrodes before and after bending test, BMNO films grown onto the graphene bottom electrode showed no change of the microstructure and the leakage current density after the bend.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.181-185
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• 2006

The flexible 2-inch AMOLED with $176{\times}144$ pixels has been demonstrated using top emission OLED driven by organic thin film transistors (OTFTs). For the development of AMOLED display on plastic substrate, we have developed several integration and unit process technologies. Through the optimization of the process based on plastic substrate, OTFT backplane with 2 transistors and 1 capacitor in a pixel has been fabricated and integrated with top emission OLED. The active addressing by OTFT driving circuit has been achieved and green light with 15 $cd/m^2$ at 15V has been observed.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.5
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• pp.212-219
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• 2000

This paper deals with a systematic approach to GA-PI controller design for static VAR compensator(SVC) using genetic algorithms(GAs) which are search algorithms based on the mechanics of natural of natural selection and natural genetics, to improve system stability. A SVC, one of the Flexible AC Transmission System(FACTS), constructed by a fixed capacitor(FC) and a thyristor controlled reactor(TCR), is designed and implemented to improve the damping of a synchronous generator, as well as controlling the system voltage. To verify the robustness of the proposed method, considered dynamic response of generator used deviation and generator terminal voltage by applying a power fluctuation and three-phase fault at heavy load, normal load and light load. Thus, we proved usefulness of GA-PI controller design to improve the stability of single machine-infinite bus with SVC system.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.7
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• pp.324-332
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• 2001

In this paper, it is suggested that the selection method of parameter of Power System Stabilizer(PSS) with robustness in low frequency oscillation for Static VAR Compensator(SVC) using a Real Variable Elitism Genetic Algorithm(RVEGA). A SVC, one of the Flexible AC Transmission System(FACTS), constructed by a fixed capacitor(FC) and a thyristor controlled reactor(TCR), is designed and implemented to improve the damping of a synchronous generator, as well as controlling the system voltage. The proposed PSS parameters are optimized using RVEGA in order to maintain optimal operation of generator under the various operating conditions. To decrease the computational time, real variable string is adopted. To verify the robustness of the proposed method, we considered the dynamic response of generator speed deviation and generator terminal voltage by applying a power fluctuation and three-phase fault at heavy load, normal load and light load. Thus, we prove the usefulness of proposed method to improve the stability of single machine-infinite bus with SVC system.