• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1204-1209
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• 2000

Many analytical and experimental studies on the active suppression of nonlinear panel flutter by using piezoceramic patch have been carried out. However, these active control methods have a few important problems; a large amount of power is required to operate actuators, and additional apparatuses such as sensor systems and controller are needed. In this study passive suppression schemes for nonlinear flutter of composite panel, which is believed to be more robust suppression system than active control in practical operation, are proposed by using piezoelectric inductor-resistor series shunt circuit. Toward the end, a finite element equation of motion for an electromechanically coupled system is proposed using the Hamilton's principle. To achieve the best damping effect, optimal shape and location of the piezoceramic(PZT) patches are determined by using genetic algorithms. The results clearly demonstrate that the passive damping scheme by using piezoelectric shunt circuit can effectively attenuate the flutter.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.977-978
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• 2007

The phase angle which is mainly depend on time constant $\tau$ of the calculable 10 A and 0.1 ${\Omega}ac/dc$ resistor has been analysed. The low values of resistors are usually inductive and time constant $\tau$ very large compare to high values of resistors. The numerical analysis has been shown that the time constant $\tau$ becomes zero when introduce the compensation capacitance geometrically to the resistive coil with proper dimension. As a result a very low phase angle can be achieved within the realizable dimensions.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.151-160
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• 2017

This paper presents a new technique of reference current generator based on Kalman filter (KF) estimator for three-phase shunt active power filter (APF). The stationary reference frame (d-q algorithm) is used to transform the load currents into DC component. The harmonics of load currents are extracted and the three-phase reference currents are generated using KF estimator. The work is simulated using Matlab/Simulink platform. To validate the simulation results, an experimental test-rig have been perform using real-time control dSPACE DS1104. In addition, hysteresis current control was used to generate the switching signal for the correction of the harmonics in the system. The non-linear load were constructed with three-phase rectifier which connected in series with inductor and parallel with resistor and capacitor. The results shows that the new technique of shunt APF embedded with KF is proven to eliminate the harmonics created by the non-linear load with some improvement on the total harmonics distortion (THD).

• 한국초전도학회:학술대회논문집
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• v.14
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• pp.57-57
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• 2004

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.313-316
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• 2002

In this paper, we present an online scheme for parameter estimation of solar cell, based on the model adjustment technique and a genetic algorithm. The ideal diode model and the diode model with series and shunt resistor are used to estimate their parameters. Simulation works using field data in the form of a VI characteristic curve are carried out to demonstrate the effectiveness of the proposed method.

• International Journal of Safety
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• v.6 no.1
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• pp.22-25
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• 2007

Damping out high frequency low amplitude structural vibrations using PZT bimorph is presented. Static and Dynamic analyses of the piezoelectric bimorph bender were performed. Three layer piezoelectric actuators were modeled with SOLID5 coupled-field elements using ANSYS. Static deflection and modal analyses of the piezoelectric bimorph bender are presented. Proper tuning of the values of the resistor and inductor in the shunt circuit is required for maximum vibration suppression.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.109-110
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• 2016

영구자석 동기 전동기(PMSM)의 결선방법에 따라 전동기의 전압과 전류는 그 크기와 위상에 차이가 발생한다. 따라서, 결선을 고려한 영구자석 동기 전동기의 제어가 필요하다. 본 논문에서는 와이 결선과 델타 결선된 전동기의 등가회로를 모델링하고, 델타 결선된 영구자석 동기 전동기의 구동 시스템에서 직류단 션트저항을 이용한 3상 전류 추정 알고리즘을 제안하였다. 컴퓨터 시뮬레이션을 통해 제안한 알고리즘의 타당성을 검증하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.90-97
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• 2006

We report our research work on the millimeter-wave broadband amplifier integrating the shunt peaking technology with the cascode configuration. The millimeter-wave broadband cascode amplifier on MIMIC technology was designed and fabricated using $0.1{\mu}m\;{\Gamma}-gate$ GaAs PHEMT, CPW, and passive library. The fabricated PHEMT has shown a transconductance of 346.3 mS/mm, a current gain cut off frequency ($f_T$) of 113 GHz, and a maximum oscillation frequency ($f_{max}$) of 180 GHz. To prevent oscillation of designed cascode amplifier, a parallel resistor and capacitor were connected to drain of common-gate device. For expansion of the bandwidth and flatness of the gain, we inserted the short stub into bias circuits and the compensation transmission line between common-source device and common-gate device, and then their lengths were optimized. Also, the input and output stages were designed using the matching method to obtain the broadband characteristic. From the measurement, we could confirm to extend bandwidth and flat gain by integrating the shunt peaking technology with the cascode configuration. The cascode amplifier shows the broadband characteristic from 19 GHz to 53.5 GHz. Also, the average gain of this amplifier is about 6.5 dB over the bandwidth.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.5
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• pp.403-406
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• 2019

We prepared yarned carbon nanotube (CNT) fibers from a CNT forest synthesized on a Si wafer by chemical vapor deposition (CVD). The yarned CNT fibers were thermally annealed to reduce their resistance by removing the amorphous carbonaceous impurities present in the fibers. The resistance of the yarned CNT fiber gradually decreased with an increase in the annealing temperature from $200^{\circ}C$ to $400^{\circ}C$ but increased again above $450^{\circ}C$. We carried out thermogravimetric analysis (TGA) to confirm the burning properties of the amorphous carbonaceous impurities and the crystalline CNTs present in the fibers. The pattern of the mass change of the sample CNT fibers was very similar to that of the resistance change. We conclude that CNT fibers should be thermally annealed at temperatures below $400^{\circ}C$ for reducing and stabilizing their resistance.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.663-665
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• 2000

We fabricated resistive superconducting fault current limiters (SFCL) based on YBCO thin films grown on 2-inch diameter saphire substrates Two SFCLs with nearly identical properties were connected in series to investigate the simultaneous quench. There was a slight difference in the rate of voltage increase between two SFCL units when they were operated independently. This difference. however, resulted in significantly unbalanced power dissipation between the units. This imbalance was removed by connecting a shunt resistor to an SFCL in parallel. The appropriate values of the shunt resistances were $80{\Omega}$ at $75 V_{rms}$. $100{\Omega}$ at $100 V_{rms}$ and $110{\Omega}$ at $120 V_{rms}$, respectively. Increased power input at high voltages also reduced the initial imbalance in power dissipation. but with increase in film temperature to higher than 200 K.