• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.34-42
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• 2004

In this paper, a double gimbal is used for roll/yaw attitude control of spacecraft and two feedback controllers are designed. One is a PD controller of no phase difference between roll and yaw control input. The other is a PD controller with a phase lag compensator about the yaw control input. The phase lag compensator is designed a first order system and a lag parameter is designed for the control of yaw angle. There are two case simulations for each of controllers; constant disturbance torques and initial errors of nutation. We obtain the results through simulations that a steady-state error and a rising time of yaw angle are developed by the compensator. In this paper, simulation parameters use the values of KOREASAT 1.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.26-34
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• 2015

In this paper, a fuzzy compensated PID control system is proposed for formation control of mobile robots. The control system consists of a kinematic controller based on the leader-follower approach and a dynamic controller to handle dynamics effects of mobile robots. To maintain the desired formation of mobile robots, the dynamic controller is equipped with a PID controller; however, the PID controller has poor performance in nonlinear and changing environments. In order to improve these problem, we applied the additional fuzzy compensator. Finally, the proposed control system has been evaluated through computer simulation to demonstrate the improved results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.137-144
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• 2006

This paper proposes the design of a robust controller based on disturbance observer which is strong to variation of system parameters, uncertainty of models or external disturbance. The controller consists of a mode based compensator and a feedback controller based on two-loop structure. The compensator in the internal-loop removes internal and external disturbances and a feedback controller in the external loop achieves performance along with given specifications. As a result, it shows that the proposed robust controller can stabilize a system against disturbance and improve controlling performance.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.965-967
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• 2001

전원 측 전압강하/상승 (Voltage sag/swell)을 보상하기 위한 동적전압보상기(Dynamic Voltage Restorer)등의 직렬 보상기에서 스위칭으로 인한 인버터 출력전압의 맥동(ripple)을 제거하기 위해 LC 필터가 사용된다. 본 논문에서는 LC 필터에서 커패시터의 전압을 상태 궤환을 이용하여 제어하는 알고리즘을 제시한다. LC 필터의 이산시간 상태 방정식을 구한 후, 궤환 이득값을 구하는 과정이 z-평면에서 이루어진다. 그리고, 제어기의 계산지연을 고려하여, 상태 관측기를 설계한다. 제안된 제어기는 기존 직렬보상기와 달리 전류 센서를 필요로 하지 않기 때문에 경제적인 이점을 가지게 된다.

• Journal of Energy Engineering
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• v.9 no.4
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• pp.342-347
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• 2000

최근 산업계에서 급증하는 전력수요와 부하의 다양화는 전원의 안정도에 악영항을 미치고 있다. 이는 전압강하는 역률 저하 유/무효 전력의 변동을 초래하고 타부하에 영향을 미치게 되므로 이를 효과적으로 보상할 수 있는 종합적인 보상 시스템이 필요하다. 본 논문에서는 이러한 전력보상 시스템중의 하나로서 플라이휠을 장착한 권선형 유도기의 2차 여자방식을 제시한다. 본 시스템은 전동기 2차 여자방식을 이용함으로서 기존의 정지형 보상기에 비하여 인버터의 용량을 기존의 것보다 수배 감소시킬 수 있는 장점이 있으며 히스테리시스 전류제어기를 사용하여 직접 전류제어기를 사용하여 직접전류 제어방식을 이용하므로 기존의 시스템과 비교하여 PI제어기의 게인선정의 어려움을 극복하고 제어 알고리즘을 간략화 할 수 있는 특징을 가지고 있다. 또한 전력을 보상하기 위한 에너지 저장요소로 플라이휠의 관성에너지를 사용함으로서 기존의 배터리 방식의 무정전 전원공급장치를 대신하는 효과를 보인다. 설계된 시스템과 제어방식은 시뮬레시션을 통하여 입증하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.2
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• pp.152-160
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• 2000

This paper addresses the analysis and design of fuzzy-model-based controller for nonlinear systems using extended PDC and optimal pole-placement schemes. In the design procedure, we represent the nonlinear system using a Takagi-Sugeno fkzy model and formulate the controller rules by using the extended parallel distributed compensator (EPDC) and construct an overall fuzzy logic controller by blending all local state feedback controllers with an optimal pole-placement scheme. Unlike the commonly used parallel distributed compensation technique, by blending a newly extended parallel distributed compensator and the optimal poleplacement schemes, we can design not only a local stable k z y controller but also an overall stable fuzzy controller to perform the tacking control objective. Furthermore, a stability analysis is carried out not only for the fuzzy model but also for a real nonlinear system. Finally. the effectiveness and feasibility of the proposed fizzy model-based controller design method has been shown through a simulation example.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.84-90
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• 2004

Many control techniques have been proposed in order to improve the control performance in the control system. In the feedback control system the output of controller is generally used as the input of a plant But the undesired noise is included in the output of a controller. Therefore, there is a need to use a precompensator for rejecting the undesired noise and improving the response characteristic of a system. In this paper, the design method of a precompensator is proposed for the model following control in the I-PD control system. The proposed precompensator is implemented with a neural network. The games of a precompensator are adjusted automatically to obtain a desired response of a system when the response characteristic of a system is changed under a condition.

• Journal of Energy Engineering
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• v.13 no.1
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• pp.68-74
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• 2004

This paper presents the design of DSTATCOM (Distribution Static Synchronous Compensator) controller. The results are verified by using PSCAD/EMTDC package. The state equation derived by decomposition analysis of DSTATCOM current component is applied to load model and the combined model which considered constraint condition. In case of single line to ground fault, the conventional method of Pl control is compared with LQR control technique. LQR control is shown to be superior in terms of response profile and composition of voltage sag.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.441-442
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• 2017

본 논문에서는 계통연계 인버터가 액티프 파워 필터로 동작할 때 비선형부하에 의해 발생하는 고조파를 보상하는 제어기 설계에 대해 다룬다. 고조파 보상 기능을 포함하는 계통연계형 인버터의 제어기는 PR제어기 기반의 멀티루프 전류제어기를 사용한다. 각각의 제어기는 시스템 특성 및 안정도를 고려하여 설계되고 시뮬레이션 및 실험으로 타당성을 입증한다.

• The Journal of the Acoustical Society of Korea
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• v.34 no.1
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• pp.46-51
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• 2015

In fields of controlling acoustical noises, the overall adaptive control system is nonlinear due to the loudspeaker, amplifiers, converters, and microphones, etc. and the performance of noise control is decreased by the extent of nonlinearities, so an adaptive control system compensating nonlinear distortions is needed. In this paper, a new multi-channel adaptive noise controller was proposed, which was combined with the adaptive compensator to effectively linearize nonlinear distortions in the overall adaptive control system. Through computer simulations, the proposed adaptive compensator could linearize the nonlinear distortions and the proposed noise controller had better capability of controlling the noises than the conventional LMS controller.