• 한국지능시스템학회논문지
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• 제10권2호
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• pp.152-160
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• 2000

본 논문에서는 확장된 병렬 분산 보상기와 최적 극점 배치 방법을 사용한 비선형 시스템의 퍼지 모델 기반 제어기의 분석과 설계 방법을 제안한다. 설계과정을 설명하면 먼저비선형 시스템을 Takagi-Sugeno 퍼지 모델로 표현하고 확장된 병렬 분산 보상기를 사용하여 제어기 규칙을 작성한다. 그리고 최적 극점 배치 방법을 사용하여 국소 상태 궤환 제어기를 설계하고 이를 이용하여 전체의 퍼지논리제어기를 설계한다. 기존의 사용된 병렬 분산 보상기와는 다르게 본 논문에서 새로이 개발된 확장된 병렬 분산 보상기와 최적 극점 배치 방법을 이용함으로써 안정한 국소 퍼지 제어기의 설계뿐만 아니라 추적 제어 목적도 수행할 수 있는 전체의 안정한 퍼지 제어기도 설계할 수 있다. 게다가 전체 퍼지 모델 뿐만 아니라 실제 비선형 시스템에 대해서도 안정도 분석을 행하였다 마지막으로 제안된 퍼지 모델 기반 제어기 설계 방법의 효율성과 가능성을 하나의 시뮬레이션 예를 통하여 증명하였다.

• 전기학회논문지P
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• 제51권3호
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• pp.111-119
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• 2002

This paper proposes a speed control system based on a fuzzy logic approach, integrated with a simple and effective adaptive algorithms. And this paper attempts to provide a thorough comparative insight into the behavior of induction motor drive with PI, direct and improved fuzzy speed controller. A indirect vector controlled induction motor is simulated under varying operating condition. The validity of the comparative results is confirmed by simulation results for induction motor drive system.

• 한국산업융합학회 논문집
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• 제9권3호
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• pp.173-178
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• 2006

For the design of multivariable fuzzy control systems decomposition of control rules is a efficent inference method since it alleviates the complexity of the problem. In some systems, however, inference error of the Gupta's decomposition method is inevitable because of its approximate nature. In this paper we define indices of applicability which decides whether the decomposition method can be applied to a multivariable fuzzy system or not.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.78-90
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• 2017

This paper presents the design of closed loop controllers operating a single-phase AC-DC three-level converter for improving power quality at AC mains. Closed loop inhibits outer voltage controller and inner current controller. Simulations of three level converter with three different voltage and current controller combinations such as PI-Hysteresis, Fuzzy-Hysteresis and Fuzzy tuned PI-Hysteresis are carried out in MATLAB/Simulink. Performance parameters such as input power factor and source current total harmonic distortion (THD) are considered for comparison of the three controller combinations. The fuzzy-tuned PI voltage controller with hysteresis current controller combination provides a better result, with a source-current THD of 0.93% and unity power factor without any source side filter for the three level converter. For load variations of 25% to 100%, a THD of less than 5% is obtained with a maximum value of only 1.67%. Finally, the fuzzy-tuned PI voltage with hysteresis controller combination is implemented in a Xilinx Spartan-6 XC6SLX25 FPGA board for experimental validation of power quality enhancement. A prototype 100 W, 0-24-48 V as output converter is considered for the testing of controller performance. A source-current THD of 1.351% is obtained in the experimental study with a power factor near unity. For load variations of 25% to 100%, the THD is found to be less than 5%, with a maximum value of only 2.698% in the experimental setup which matches with the simulation results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.143-146
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• 2004

This paper is proposed adaptive fuzzy-neural network(FNN) controller for speed control of induction motor drive. The design of this algorithm based on FNN controller that is implemented using fuzzy control and neural network. A model reference adaptive scheme is proposed in which the adaptation mechanism is executed by fuzzy logic based on the error and change of error measured between the motor speed and output of a reference model. The control performance of the adaptive FNN controller is evaluated by analysis for various operating conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.728-731
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• 1997

This paper proposes the systematic auto-tuning method for fuzzy controller using genetic algorithm(GA). In general, the design of fuzzy logic controller has difficulties in the acquisition of expert's knowledge and relies to a great extent on heuristic knowledge which, in many cases, cannot be objectively justified. So, the performance of the controller can be degraded in the case of plant parameter variations or unpredictable incident which the designer may have ignored. Proposed genetic algorithm searches the optimal rule structure, parameters of membership functions and scaling factors simultaneously and automatically by a new genetic coding format. Inverted pendrum system is provided to show the advantages of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1359-1361
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• 1996

This paper describes a design of real time fuzzy controller using Minimum fuzzy control Rule Selection Method(MRSM). The control algorithm of dynamic systems needs less computation time and memory. To reduce the computation time of fuzzy logic controller, minimum number of rules are to be selected for the fuzzy input variable. The universe of discourse is divided by the number of linguistic labels to allocate the assigned membership function to the fuzzy input variables. In this case, since fuzzy input variables are continuous, scale factor SU is tuned independently. According to increment of SU control surface is improved to adapt the change of system parameter. At this, crisp control surface is increased. With the increament of crisp control surface, fuzzy control surface is reduced. When error state deviates from desirable error state, crisp control surface is more useful than fuzzy control surface for obtaining fast rising time.

• 한국항공우주학회지
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• 제40권5호
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• pp.431-438
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• 2012

고기동 무인항공기용 터보제트엔진의 고성능 운용을 위한 비선형 제어기를 설계하였다. 제트엔진의 비선형특성을 제어기 설계에 반영하기 위해 당해엔진의 동적해석코드를 개발하였고 이를 이용한 선형모델로부터 선형해석의 한계성을 검증함으로써 비선형 제어기 설계의 당위성을 보였다. PI형 퍼지제어기를 일반 미분제어기와 결합하여 효율적인 퍼지제어기를 설계하였으며, 일반 PID제어기와 비교하여 압축기서지 및 연소정지영역, 터빈온도의 제한 등 안전운전 범위 내 운전을 보장하면서도 월등한 제어성능을 보임으로써 설계된 퍼지제어기의 유용성을 입증하였다.

• 한국공간구조학회논문집
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• 제15권4호
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• pp.81-89
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• 2015

Damped outrigger systems have been proposed as a novel energy dissipation system to protect tall buildings from severe earthquakes and strong wind loads. In this study, semi-active damping devices such as magnetorheological (MR) dampers instead of passive dampers are installed vertically between the outrigger and perimeter columns to achieve large and adaptable energy dissipation. Control performance of semi-active outrigger damper system mainly depends on the control algorithm. Fuzzy logic control algorithm was used to generate command voltage sent to MR damper. Genetic algorithm was used to optimize the fuzzy logic controller. An artificial earthquake load was generated for numerical simulation. A simplified numerical model of damped outrigger system was developed. Based on numerical analyses, it has been shown that the semi-active damped outrigger system can effectively reduce both displacement and acceleration responses of the tall building in comparison with a passive outrigger damper system.

• 정보처리학회논문지C
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• 제12C권2호
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• pp.229-234
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• 2005

본 논문에서는 ATM 네트워크에서 인터넷 트래픽 성능 향상을 위한 퍼지를 응용한 버퍼 관리 알고리즘을 제안한다. 제안된 알고리즘은 퍼지 제어기를 이용해서 새로 도착하는 패킷을 버퍼의 상태와 VC의 부하에 따라 동적으로 폐기를 결정하여 버퍼 이용 효율과 GFR의 요구사항을 충족할 수 있도록 하였다. 컴퓨터 시뮬레이션을 통해 기존의 버퍼 관리 알고리즘과 성능을 비교한 결과, 공평성과 TCP 수율 면에서 성능이 향상됨을 보였다.