• Current Photovoltaic Research
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• 제2권3호
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• pp.110-114
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• 2014

We propose a low temperature sol-gel ZnO/Ag nanowire composite thin film to fulfill low temperature and low cost requirements, which are essential criteria in future flexible electronic devices. In this proposed thin film, Ag nanowire plays the role of electrical conduction, and sol-gel ZnO provides a structural medium with a high visible transmittance. Low temperature restriction in the sol-gel fabrication process prevents sufficient oxidation of Zn acetate precursors, which were solved by a post-coating treatment with ultraviolet light irradiation. Composite thin film formation was performed by spin coating methods with a mixed precursor solution or in a sequential manner. We obtained an average visible transmittance larger than 85% and a sheet resistance smaller than $50{\Omega}/sq$. After optimization in a fabricated composite transparent conductive thin film with the thickness around 100 nm. Similar experimental demonstration in a flexible substrate (polyethyleneterephthalate) was successful, which implies a promising application opportunity of this technology.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2664-2666
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• 2000

In this paper, the novel sliding mode control method with virtual state is compared to the SMC with co-states. The former method is shown to have advantage in the respect of computation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2187-2189
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• 2003

This paper presents a design method of the wavelet neural network(WNN) controller based on a direct adaptive control scheme for the intelligent control of chaotic systems. The conventional control methods such as optimal control, adaptive control and robust control may not be feasible when an explicit, faithful mathematical model cannot be constructed. Therefore, an intelligent control system that is an on-line trained WNN controller based on a direct adaptive control method is proposed to control chaotic systems whose mathematical models are not available. The gradient-descent method is used for training a wavelet neural network controller. Finally, the effectiveness and feasibility of the proposed control method is demonstrated with applications to the chaotic system.

• Journal of Power Electronics
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• 제17권4호
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• pp.983-990
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• 2017

This paper proposes a model predictive control based on the discrete Lyapunov function to improve the performance of power electronic converters. The proposed control technique, based on the finite control set model predictive control (FCS-MPC), defines a cost function for the control law which is determined under the Lyapunov stability theorem with a control error compensation. The steady state and dynamic performance of the proposed control strategy has been tested under a single phase AC/DC voltage source rectifier (S-VSR). Experimental results demonstrate that the proposed control strategy not only offers global stability and good robustness but also leads to a high quality sinusoidal current with a reasonably low total harmonic distortion (THD) and a fast dynamic response under linear loads.

• 한국산학기술학회논문지
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• 제13권8호
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• pp.3326-3333
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• 2012

본 연구에서는 이 분야의 효과적인 공학기술교육을 위하여 능동형 교육용 시뮬레이터를 개발하였다. 개발된 시스템은 주행조건 제어 및 모니터링 시스템, 섀시 전자제어 시스템 모니터링 및 분석시스템, 가상 시뮬레이터 및 교육용 콘텐츠로 구성되어 있다. 여기서 주행조건 제어 및 모니터링 시스템은 다시 실차 시뮬레이터와 유압장비 및 원격제어 및 모니터링 시스템으로 구성되어 있다. 섀시 전자제어 시스템 모니터링 및 분석 시스템에서는 Labview 프로그램을 통하여 각종 센서와 액추에이터들의 동작상태를 모니터링 할 수 있도록 하였다. 그리고 가상 시뮬레이터 및 교육용 콘텐츠는 2D 플래시 및 3D 애니메이션으로 효과적인 교육의 멀티미디어 교육 자료를 제공하여 준다. 이러한 시스템은 교육용 뿐만 아니라 관련 분야 시스템의 모듈 연구 개발 시 성능 분석 장비로써의 활용도 가능할 것이다.

• Transactions on Electrical and Electronic Materials
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• 제17권3호
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• pp.150-154
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• 2016

Contact electrodes pose threats like inflammation, metal poisoning, and allergic reaction to the user during long term ECG procedure. Therefore, we present a novel noncontact electrocardiographic electrode designed through microelectromechanical systems (MEMS) process. The proposed ECG electrode consists of small inner and large outer circular copper plates separated by thin insulator. The inner plate enables capacitive transduction of bio-potential variations on a subject’s chest into a voltage that can be processed by a signal processing board, whereas the outer plate shields the inner plate from environmental electromagnetic noise. The electrode lead wires are also coaxially designed to prevent cables from coupling to ground or electronic devices. A prototype ECG electrode has an area of about 2.324 cm², is very flexible and does not require power to operate. The prototype ECG electrode could measure ECG at about 500 um distance from the subject’s chest.

• 제어로봇시스템학회논문지
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• 제21권5호
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• pp.453-458
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• 2015

We presented a quad-rotor controlling algorithm design by using sensor fusion in this paper. The controller design technique was performed by a PD controller with a Kalman filter and compensation algorithm for increasing the stability and reliability of the quad-rotor attitude. In this paper, we propose an attitude estimation algorithm for quad-rotor based sensor fusion by using the Kalman filter. For this reason, firstly, we studied the platform configuration and principle of the quad-rotor. Secondly, the bias errors of a gyro sensor, acceleration and geomagnetic sensor are compensated. The measured values of each sensor are then fused via a Kalman filter. Finally, the performance of the proposed algorithm is evaluated through experimental data of attitude estimation. As a result, the proposed sensor fusion algorithm showed superior attitude estimation performance, and also proved that robust attitude estimation is possible even in disturbance.

• 자동차안전학회지
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• 제11권1호
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• pp.48-54
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• 2019

Optimal engine control is needed to cope with the global environmental regulations that are globally enforced. For optimum engine control, the electronic throttle control system (ETCS) is a prerequisite. Automotive makers are having an effect on reducing emissions and improving fuel economy by applying ETCS which is designed to secure stability. The ETCS controls the output of the throttle valve by passing the output value of the accelerator position sensor (APS) to the engine control unit (ECU). In this study, the authors investigated the safety standards of domestic and overseas accelerator control system and tried to understand how the air flow control affects the engine output by replacing the throttle. The authors suggest an improvement proposal of safety standard based on the result of driving evaluation by various modes.

• 한국지능시스템학회논문지
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• 제12권1호
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• pp.80-84
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• 2002

본 논문은 2자유도 실험용 헬리콥터 시스템의 제어를 위한 분산 제어기 설계 기법을 제안한다. 분산제어기법은 특히 대규모 제어 시스템에 적합하다고 알려져 있다. 본 논문에서는 Lyapunov 안정도 설계 방법을 이용하여 상호 연결된 TS 퍼지 시스템의 안정도 조건을 유도하고 선형 행렬 부등식을 이용하여 제어기 설계 조건을 공식화한다. 제안된 방법의 유용성을 검증하기 위해, 컴퓨터 시뮬레이션뿐 만 아니라 실험을 통해 그 결과를 도출한다.

• Journal of Power Electronics
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• 제12권5호
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• pp.758-768
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• 2012

This paper presents the modeling and position-sensorless vector control of a dual-airgap axial flux permanent magnet (AFPM) machine optimized for use in flywheel energy storage system (FESS) applications. The proposed AFPM machine has two sets of three-phase stator windings but requires only a single power converter to control both the electromagnetic torque and the axial levitation force. The proper controllability of the latter is crucial as it can be utilized to minimize the vertical bearing stress to improve the efficiency of the FESS. The method for controlling both the speed and axial displacement of the machine is discussed. An inherent speed sensorless observer is also proposed for speed estimation. The proposed observer eliminates the rotary encoder, which in turn reduces the overall weight and cost of the system while improving its reliability. The effectiveness of the proposed control scheme has been verified by simulations and experiments on a prototype machine.