• 분석과학
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• 제14권4호
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• pp.331-339
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• 2001

감귤류와 한국산 청피에 함유된 methoxylated flavonoids (sinenstin, nobiletin, tangeretin)를 HPLC, mass 그리고 NMR로 분리하고 분석하였다. Methoxylated flavonoids는 Chung-pi(I)과 Chung-pi(II)에 가장 풍부하게 함유되었다. 한국산 밀감에서 얻어진 Chung-pi(I), (II)의 methoxylated flavonoids 함유량은 밀감성숙도에 따라 증가하였으며, 10월 중순이후에는 서서히 감소하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.7-10
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• 1998

Because of simple control algorithm and easy implementation, the conventional PI controller has been widely used in industrial application. But, it is very difficult to find the optimal PI control gain. Therefore, in improperly tuned PI controller or parameter variation, to obtain optimal performance, the novel PI controller, which consist of conventional PI controller and 4-rule based fuzzy logic, are presented in this paper. The novel PI controller which exhibits a stabilizing effects on the closed-loop system, has good robustness regarding the improperly tuned PI controller or parameter variation. The simulations are performed to verify the capability of proposed control method on induction motor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.254_255
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• 2009

본 논문에서는 비선형 특성의 STATCOM 시스템에 대해 강인한 PI 제어기를 설계하였다. 설계된 PI 제어기는 불확실성 변수에 대해 모든 동작 점에서 항상 안정하다는 것을 보드선도, 게인, 위상 여유, Nyquist 선도를 통해 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.629-632
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• 2003

Piezo actuators are mainly used in precision position control system because of their high position resolution. Although there have been many approaches in open loop control of this, those method turn out to be not effective in precision control due to hysteresis and creep. To overcome the problems, closed loop PI control method is used in commercial products. However, it is very difficult to obtain fast response with conventional PI control although piezo actuator has fast response. In this paper, we propose a fuzzy PI control method with the proposed fuzzy PI controller, we obtains faster settling response over the conventional PI controller. We verify the effectiveness of the proposed method with experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2012-2014
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• 1998

The conventional PI controller has been widely used in industrial applications. If a PI control gain is selected suitable, the PI controller shows very good control performance. But it is very difficult to find the optimal PI control gain. Therefore, in this paper, the 4-rule based fuzzy logic modifier of the conventional PI controller are presented. The fuzzy logic modifier which exhibits a stabilizing effects on the closed-loop system, has good robustness regarding the improperly tuned PI controller. The simulation are performed to verify the capability of proposed control method on vector controlled induction motor drive system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.531-533
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• 1997

PI(proportional-integral) controller has been extensively used in the industrial field. But in practicle case, it is difficult to tune PI gains. Evolution Strategy(ES) is used as an effective search algorithm in optimization programs. In this paper we proposed a PI controller for Spot welder system using ES with varying search space. ES with varying search space which depends on fitness values at each generation is used to tune PI control parameters. Simulation results show the proposed algorithm has accurate and robust performance with effective search ability.

• 조명전기설비학회논문지
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• 제21권6호
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• pp.33-39
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• 2007

본 논문은 부하에 대한 빠른 응답 특성을 보이는 새로운 SRM 구동 토폴로지를 제안하였다. PI 제어기 출력이 포화될 때 windup 현상이 나타나고 그 결과로 성능이 저하된다. 따라서 전동기의 가변속 제어 성능을 위해 가속 시에는 개선된 Anti-Windup PI 제어기만을 사용하고 감소 시에는 추가로 부하의 특성을 고려하여 braking 동작을 사용하였다. 시뮬레이션 및 실험 결과는 속도 성능면에서 제안된 방식이 종래의 다른 제어 방식에 비해 우수함을 보여 준다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.260-262
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• 2006

This paper presents Hybrid-PI controller of induction motor drive using fuzzy control. In general, PI controller in computer numerically controlled machine process fixed gain. They may perform well under some operating conditions, but not all. To increase the robustness, fixed gain 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 induction motor 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.

• 제어로봇시스템학회논문지
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• 제13권3호
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• pp.192-197
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• 2007

This paper presents Hybrid PI controller of IPMSM drive using fuzzy adaptive mechanism(FAM) control. In general, PI controller in computer numerically controlled machine process fixed gain. They may perform well under some operating conditions, but not all. To increase the robustness, fixed gain 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.

• 전기학회논문지
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• 제60권10호
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• pp.1978-1983
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• 2011

BLDC motor is used in a wide variety of industrial and servo applications. Its features and advantages mainly consist in high value of torque/inertia ratio, high efficiency with speed range and high dynamic performance. This paper deals with the speed control of a trapezoidal type brushless DC motor using Fuzzy PI controller. The conventional PI controller has been widely used in industrial applications. If we select a optimal PI control gain, the PI controller shows very good control performance. But it is very difficult to find the optimal PI control gain. Fuzzy control does not need any model of plant and is basically adaptive and gives robust performance for plant parameter variation. Therefore the combinations of conventional PI controller and fuzzy controller seem to be very effective. This paper deals with PI controller with 4-rule based fuzzy controller. The proposed fuzzy PI controller increases the control performance of the conventional PI controller. Simulation and experimental results show that fuzzy PI controller has a good robustness regarding the improper tuned PI controller.