• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.614-616
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• 2004

It is waste of time in industrial plant that the PI controller gain tuning. The PI controller has many trial-and-error steps for gain design. This paper proposes the optimum gain design of PI controller using a speed estimation in sensorless vector-control. In this method, a degree of stability and Hurwitz theory are applied and the controller gain is expressed by system parameters.

• 대한기계학회논문집A
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• 제36권7호
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• pp.797-803
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• 2012

비례솔레노이드밸브는 코일전류에 비례하는 전자기력을 이용하여 밸브 변위를 연속적으로 가변시키는 밸브이다. 대용량 비례유량제어밸브는 발전소나 화학 플랜트에서 물, 스팀, 가스 등과 같은 공정유체의 대용량 유량제어에 사용되며 공압이나 모터를 이용하는 밸브에 비하여 우수한 응답성능과 소형화의 장점을 가진다. 본 연구에서는 비례제어밸브를 대상으로 밸브의 동적 특성을 식별한 후 목표 성능이 만족되도록 위치제어기의 비례적분이득을 자동으로 조정하는 기능을 설계하였다. 동특성 식별은 릴레이 피드백을 통하여 한계 안정 상태에서의 임계이득과 임계주기로 파악하였으며, 비례적분이득 결정에는 Ziegler-Nichols 방법을 적용하였다. 구현된 기능은 시험을 통하여 성능을 검증하였으며 밸브 작동점과 릴레이 제어기 변수가 자동조정에 미치는 영향을 분석하였다.

• 조명전기설비학회논문지
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• 제23권12호
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• pp.191-200
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• 2009

본 논문에서는 전력계통에서 발생하는 저주파 진동을 억제하여 계통에 댐핑력을 제공함으로써 계통 안정도를 향상시킬 수 있는 전력계통 안정화장치의 정수선정 기법과 현장시험을 통한 성능검증 방법을 제시하였다. 대상 발전기는 우리나라 계통에 설치되어 있는 612[MVA]급 화력발전기이며, 축 속도를 입력으로 하는 아날로그 전력계통 안정화장치를 적용대상으로 하였다. 본 논문에서는 먼저, 오프라인에서 선형 해석 및 고유치 해석을 통하여 최적정수를 선정하는 기법을 제시하고, 시간영역 과도 안정도 해석을 이용하여 선정된 정수를 검증하였다(Part I). 또한, 선정된 전력계통 안정화장치의 성능을 온라인 현장시험을 통하여 최종적으로 검증하였으며, 정수선정 전 후의 오프라인 시뮬레이션 결과와 온라인 시험결과를 비교 분석함으로써, 결정된 모델의 적정성을 확인하였다(Part II). 이를 통하여, 축 속도를 입력으로 하는 PSS의 정수선정 방법과 실 계통 현장시험을 통한 성능검증 방법을 제시하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권1호
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• pp.8-17
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• 2002

This paper suggests that the immune algorithm can effectively be used in tuning of a PID controller. The artificial immune network always has a new parallel decentralized processing mechanism for various situations, since antibodies communicate to each other among different species of antibodies/B-cells through the stimulation and suppression chains among antibodies that form a large-scaled network. In addition to that, the structure of the network is not fixed, but varies continuously. That is, the artificial immune network flexibly self-organizes according to dynamic changes of external environment (meta-dynamics function). However, up to the present time, models based on the conventional crisp approach have been used to describe dynamic model relationship between antibody and antigen. Therefore, there are some problems with a less flexible result to the external behavior. On the other hand, a number of tuning technologies have been considered for the tuning of a PID controller. As a less common method, the fuzzy and neural network or its combined techniques are applied. However, in the case of the latter, yet, it is not applied in the practical field, in the former, a higher experience and technology is required during tuning procedure. In addition to that, tuning performance cannot be guaranteed with regards to a plant with non-linear characteristics or many kinds of disturbances. Along with these, this paper used immune algorithm in order that a PID controller can be more adaptable controlled against the external condition, including moise or disturbance of plant. Parameters P, I, D encoded in antibody randomly are allocated during selection processes to obtain an optimal gain required for plant. The result of study shows the artificial immune can effectively be used to tune, since it can more fit modes or parameters of the PID controller than that of the conventional tuning methods.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.121-124
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• 2009

In this paper, the techniques and design focus of flexible gain coltrol of LAN(Low Noise Amplifier) using the TSMC 0.18um CMOS process. The design frequency set up a standard on 2.4GHz that is used in Zigbee system. The design concepts a basic Cascode LNA techniques and a swiching circuit consisted of 4 NMOS of load resistance, which convert the output impedenceby tuning on or off. The result show the gain change by NMOS operated swich. The simulation result is that Gain is 14.07dB-16.79dB and NF(Noise Figure) is 1.06dB-1.09dB.

• ETRI Journal
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• 제28권3호
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• pp.386-388
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• 2006

Monolithic SiGe heterojunction bipolar transistor (HBT) variable gain amplifiers (VGAs) with a feedforward configuration have been newly developed for 5 GHz applications. Two types of the feedforward VGAs have been made: one using a coupled-emitter resistor and the other using an HBT-based current source. At 5.2 GHz, both of the VGAs achieve a dynamic gain-control range of 23 dB with a control-voltage range from 0.4 to 2.6 V. The gain-tuning sensitivity is 90 mV/dB. At $V_{CTRL}$= 2.4 V, the 1 dB compression output power, $P_{1-dB}$, and dc bias current are 0 dBm and 59 mA in a VGA with an emitter resistor and -1.8 dBm and 71mA in a VGA with a constant current source, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1137-1139
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• 2002

In this paper, recurrent artificial neural network (RNN) based self tuning speed controller is proposed for the high performance drives of induction motor. RNN provides a nonlinear modeling of motor drive system and could give the information of the load variation, system noise and parameter variation of induction motor to the controller through the on-line estimated weights of corresponding RNN. Thus, proposed self tuning controller can change gains of the controller according to system conditions. The gain is composed with the weights of RNN. For the on-line estimation of the weights of RNN, extended kalman filter (EKF) algorithm is used. Self tuning controller that is adequate for the speed control of induction motor is designed. The availability of the proposed controller is verified through the MATLAB simulation with the comparison of conventional PI controller.

• 전자공학회논문지A
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• 제33A권6호
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• pp.52-61
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• 1996

In this paper, harmonic-tuning method to achieve the maximum efficiency is proposed. Harmonic tuning method is applied to the optimum load impedance of a class B amplifier, which is extracted by using the modified cripps method. High efficiency power amplifier utilizing GaAs MESFET is designed and fabricated in the 835MHz band. The performance of th eamplifier is presented by having output power of 30.8dBm, drain efficiency of 80.5% and power added efficiency of 66% with an associated power gain of 7.4dB.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.15-16
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• 2008

This paper describes the on-site PSS Tuning Test of EX2000 excitation of Dangin T/P #4. The on-line 2% AVR step test in 500MW was performed by setting PSS gain from 0 to 15 by 3 increasement. The time-domain measured data was also analyzed by DFT analysis. Finally, the measured data was replicated and verified by running the time-domain dynamic simulation.

• 한국지능시스템학회논문지
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• 제12권3호
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• pp.261-268
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• 2002

This paper represents that auto tunings of membership functions and weights in the fuzzy neural networks are effectively performed by immune algorithm. A number of hybrid methods in fuzzy-neural networks are considered in the context of tuning of learning method, a general view is provided that they are the special cases of either the membership functions or the gain modification in the neural networks by genetic algorithms. On the other hand, since the immune network system possesses a self organizing and distributed memory, it is thus adaptive to its external environment and allows a PDP (parallel distributed processing) network to complete patterns against the environmental situation. Also, it can provide optimal solution. Simulation results reveal that immune algorithms are effective approaches to search for optimal or near optimal fuzzy rules and weights.