• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.191-193
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• 2005

This paper presents Hybrid PI controller of IPMSM drive using fuzzy adaptive mechanism(FAM) control. To increase the robustness, fixed gam PI controller, Hybrid PI controller proposes a new method based self tuning PI controller. Hybrid PI controller is developed to minimize overshoot and settling time following sudden parameter changes such as speed, load torque, inertia, rotor resistance and self inductance. The results on a speed controller of IPMSM are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fixed gains one in terms of robustness, even under great variations of operating conditions and load disturbance.

• Journal of Power Electronics
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• 제14권5호
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• pp.1008-1027
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• 2014

An electric scooter with a V-belt continuously variable transmission (CVT) driven by a permanent magnet synchronous motor (PMSM) has a lot of nonlinear and time-varying characteristics, and accurate dynamic models are difficult to establish for linear controller designs. A PMSM servo-drive electric scooter controlled by a novel hybrid modified recurrent Legendre neural network (NN) control system is proposed to solve difficulties of linear controllers under the occurrence of nonlinear load disturbances and parameters variations. Firstly, the system structure of a V-belt CVT driven electric scooter using a PMSM servo drive is established. Secondly, the novel hybrid modified recurrent Legendre NN control system, which consists of an inspector control, a modified recurrent Legendre NN control with an adaptation law, and a recouped control with an estimation law, is proposed to improve its performance. Moreover, the on-line parameter tuning method of the modified recurrent Legendre NN is derived according to the Lyapunov stability theorem and the gradient descent method. Furthermore, two optimal learning rates for the modified recurrent Legendre NN are derived to speed up the parameter convergence. Finally, comparative studies are carried out to show the effectiveness of the proposed control scheme through experimental results.

• Korean Chemical Engineering Research
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• 제51권5호
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• pp.640-643
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• 2013

폴리스티렌 콜로이드 에멀젼 용액에서 물이 증발하게 되면 순간적으로 폴리스티렌 콜로이드 입자들이 물 표면으로 튀어나오게 되며 이러한 입자들 간의 모세관력에 의해 자기조립이 일어나게 되는데, 폴리스티렌 입자의 경우 유효밀도가 물 보다 작아 물 표면 위에 3차원 광결정을 형성하게 된다. 본 논문에서는 이러한 현상을 젖음성이 있는 제한된 공간을 가지는 구조를 가지는 유리기판 위에서 일어나도록 함으로써, 3차원의 폴리스티렌 콜로이드 결정이 고속으로 생성되고 기판위로 옮겨질 수 있도록 고안하였다. 고속으로 제작된 폴리스티렌 콜로이드 광결정은 폴리스티렌 입자의 크기 및 광결정 필름의 입사각을 조절하여 가시광 전체 영역의 빛을 선택적으로 반사하는 광필터로 적용해 보았다.

• Korean Chemical Engineering Research
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• 제45권1호
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• pp.12-16
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• 2007

Copper-Zinc Oxide를 촉매로 사용하는 메탄올 자열 개질 반응기의 온도제어 연구를 하였다. 반응기 hot-spot에서 1 cm 벗어난 지점의 반응기 내부 온도를 피제어변수로, 공기 유량을 조작변수로 사용하였다. 일차 시간 지연 모델을 얻었으며, 이로부터 IMC-PI 법을 적용하여 제어기 값을 구할 수 있었다. 이 제어기로 100시간 이상 개질 반응기 내부의 온도를 ${\pm}5^{\circ}C$ 내에서 제어할 수 있었다. 촉매활성의 저하로 인한 hot-spot 지점의 변화를 조사하여, 적응 제어의 설계에 이용할 수 있게 하였다.

• Journal of Positioning, Navigation, and Timing
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• 제5권1호
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• pp.1-9
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• 2016

Range-based wireless localization system must measure accurate range between a mobile node (MN) and reference nodes. However, non-line-of-sight (NLOS) error caused by the spatial structures disturbs the localization system obtaining the accurate range measurements. Localization methods using the range measurements including NLOS error yield large localization error. But filter-based localization methods can provide comparatively accurate location solution. Motivated by the accuracy of the filter-based localization method, a filter residual-based NLOS error estimation method is presented in this paper. Range measurement-based residual contains NLOS error. By considering this factor with NLOS error properties, NLOS error is mitigated. Also a process noise covariance matrix tuning method is presented to reduce the time-delay estimation error caused by the single dynamic model-based filter when the speed or moving direction of a MN changes, that is the used dynamic model is not fit the current dynamic of a MN. The presented methods are evaluated by simulation allowing direct comparison between different localization methods. The simulation results show that the presented filter is more accurate than the iterative least squares- and extended Kalman filter-based localization methods.

• Journal of the Optical Society of Korea
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• 제16권3호
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• pp.305-312
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• 2012

We numerically demonstrate the performance of a plasmonic lens composed of an array of nanoslits perforated on thin metallic film with slanted cuts on the output surface. Embedding Kerr nonlinear material in nanoslits is employed to modulate the output beam. A two dimensional nonlinear-dispersive finite-difference time-domain (2D N-D-FDTD) method is utilized. The performance parameters of the proposed lens such as focal length, full-width half-maximum, depth of focus and the efficiency of focusing are investigated. The structure is illuminated by a TM-polarized plane wave and a Gaussian beam. The effect of the beam waist of the Gaussian beam and the incident light intensity on the focusing effect is explored. An exact formula is proposed to derive electric field E from electric flux density D in a Kerr-Dispersive medium. Surface plasmon (SPs) modes and Fabry-Perot (F-P) resonances are used to explain the physical origin of the light focusing phenomenon. Focused ion beam milling can be implemented to fabricate the proposed lens. It can find valuable potential applications in integrated optics and for tuning purposes.

• 한국전자파학회논문지
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• 제13권1호
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• pp.68-73
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• 2002

본 논문에서는 타키오닉스의 SiGe HBT 파운더리를 이용하여 50 MHz에서 3 GHz까지 동작하는 광대역 RFIC 증폭기를 구현한다. 평탄한 이득특성과 광대역 임피던스 정합을 위하여 voltage-shunt 피드백 구조를 이용하였으며, 저주파 소신호 해석을 이용하여 설계 파라메터의 초기값을 결정하였다. 설계시점에서 HBT의 대신호 모델이 준비되지 않았기 때문에 저주파에서 유효한 튜닝보드를 제작하여 설계 파라메터를 미세 조정하였다. 제작된 증폭기는 12 dB 이득에 1 dB 이득 변동특성을 갖고 있으며, P1 dB는 850 MHz에서 15 dBm이다.

• Journal of Power Electronics
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• 제5권3호
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• pp.198-205
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• 2005

The mechanical system of a drive can often be modeled as a two- or three-mass-system. The load is coupled to the driving motor by a shaft able to perform torsion oscillations. For the automatic tuning of the control, it is necessary to know the mathematical description of the system and the corresponding parameters. As the manpower and setup-time necessary during the commissioning of electrical drives are major cost factors, the development of self-operating identification strategies is a task worth pursuing. This paper presents an identification method which can be utilized for the assisted commissioning of electrical drives. The shaft assembly can be approximated as a two-mass non-rigid mechanical system with four parameters that have to be identified. The mathematical background for an identification procedure is developed and some important implementation issues are addressed. In order to avoid the excitation of the system with its natural resonance frequency, the frequency response can be obtained by exciting the system with a Pseudo Random Binary Signal (PRBS) and using the cross correlation function (CCF) and the auto correlation function (ACF). The reference torque is used as stimulation and the response is the mechanical speed. To determine the parameters, especially in advanced control schemes, a numerical algorithm with excellent convergence characteristics has also been used that can be implemented together with the proposed measurement procedure in order to assist the drive commissioning or to achieve an automatic setting of the control parameters. Simulations and experiments validate the efficiency and reliability of the identification procedure.

• 한국항공우주학회지
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• 제37권8호
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• pp.759-766
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• 2009

본 논문은 INS/vSLAM 통합 항법 시스템의 성능 향상을 위한 기초 연구로써, 비전 센서의 영상처리 성능을 향상을 위한 알고리즘 개발에 목표를 두고 있다. 비전센서의 영상처리알고리즘으로 SIFT 알고리즘을 사용하였으며, SIFT 알고리즘의 특징점 정합 성능을 개선하기 위해 특징점 정합 필터를 적용하였다. 본 논문에서 제안한 알고리즘을 이용하여 기존의 SIFT 알고리즘을 파라미터 조절한 경우보다 향상된 결과를 얻을 수 있었다. 차후 실시간 통합 항법 시스템에 적용하기 위해서 알고리즘의 속도를 향상시키는 작업이 필요하다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.359-360
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• 2012

This paper proposes a scheme of auto-tuning fuzzy PI controller and input voltage feed forward to control the output voltage of a three-phase Z-source inverter (ZSI). The proposed scheme adjusts the ts (Kp and Ki) in real time in order to find the most suitable Kp and Ki for PI controller and to simplify the controller design. The proposed scheme is verified the validity by experiment and co-simulation in PSIM and MATLAB/SIMULINK both load step change and input DC voltage variation in Z-source inverter, and has compared with the conventional PID control scheme. The experiment results involve of three-phase output voltage, Z-network capacitor voltage and dc-link peak voltage value. By those analysis and comparison, the availability of the proposed method in output voltage transient response quality improving has been verified. Compared with conventional PID method, the proposed method showed a more effective and robust control performance for coping with the severe disturbance conditions.