• 대한전기학회논문지:전력기술부문A
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• 제48권3호
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• pp.247-256
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• 1999

In this paper, a methodology for optimal design of PID controller using the modified genetic algorithm has been proposed to improve the transient stability at system fault in HVDC transmission system, mathematical model preparation for stability analysis, and supplementary signal control by an optimal PID controller using the modified genetic algorithm(MGA). The propriety was verified through computer simulations regarding transient stability. It means that the application of MGA-PID controller in HVDC transmission system can contribute the propriety to the improvement of the transient stability in HVDC transmission system and the design of MGA-PID controller has been proved indispensible when applied to HVDC transmission system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.68-68
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• 2000

This paper presents a fuzzy modified PID controller that uses linear fuzzy inference method. In this structure, the proportional and derivative gains vary with the output of the system under control. 2-input PD type fuzzy controller is designed to obtain the varying gains. The proposed fuzzy PID structure maintains the same performance as the general-purpose linear PID controller, and enhances the tracking performance over a wide range of input. Numerical simulations and experimental results show the effectiveness of the fuzzy PID controller in comparison with the conventional PID controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.128-130
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• 2005

This paper proposes a modified IMC-PID controller that introduces controlling factor of the system identification to the standard IMC-PID controller in order to meet the design specifications such as gain, phase margin and maximum magnitude of sensitivity function in the frequency domain as well as the design specifications in time domain, settling, rising time and overshoot, and so on.

• 한국정밀공학회지
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• 제12권4호
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• pp.111-118
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• 1995

This paper presents the modified fuzzy-compensated PID(FCPID) control, which involves adding the compensator to an existing PID controller, to improve the performances of the systems. Compared to a conventional PID control and a fuzzy logic control(FLC), the proposed control scheme has superior performance. Experimental results of an actual implementation of the modified PC-based FCPID controller on the DC servo-motor demonstrate considerable improve- ment of the performance of the existing FCPID control by monitoring the scaling factor. They show faster responses and smaller overshoots than the conventional FCPID control scheme for the various reference inputs and the robustness to the loads.

• 전자공학회논문지SC
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• 제42권6호
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• pp.15-22
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• 2005

본 논문에서는 PID 제어기와 PI-PD 제어기 사이의 관계를 분석하여 이 두 제어기의 affine 집합을 구성하는 PID 제어기의 변형된 형태인 PID-PD 제어기와 그 동조 방법을 새롭게 제안한다. 제안된 설계 방법은 PID와 PI-PD 제어기를 이용한 전체 폐루프 시스템인 시간 응답을 경계로 그 사이의 응답을 보이도록 설계할 수 있다. 그 동조 방법으로 특정한 가격함수를 선정하여 이를 최소화하는 최적 동조법을 적용하여 제어를 설계하였다. 제안된 제어기의 유용성을 사례 연구와 분석을 통해 검토했다.

• 전력전자학회논문지
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• 제17권2호
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• pp.135-141
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• 2012

PMSM(Permanent Magnet Synchronous Motor) has periodic torque ripple from the cogging torque and load conditions. This paper proposes the modified PID speed controller to reduce the speed ripple of the PMSM. The proposed modified PID controller uses a selective D(Differential) control term according to the speed error and the differential of the speed error. The proposed speed controller produces an additional torque reference such as torque compensator based on PI controller according to the speed error and the differential of the speed error, and it can reduce the vibration of the conventional D-control term with reduced speed ripple. Since the additional torque reference of the proposed speed controller is changed by the sign of the speed error and the differential of the speed error, a simple function to determine the sign of the error is used to produce the compensated torque. The proposed control scheme is verified by the computer simulation and the experiments.

• 제어로봇시스템학회논문지
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• 제7권7호
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• pp.622-631
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• 2001

This paper presents a fuzzy modified PID controller that uses linear fuzzy inference method. In this structure, the proportional and derivative gains vary with the output of the system under control. 2-input PD type fuzzy controller is designed to obtain the varying gains. The proposed fuzzy PID structure maintains the same performance as the same performance as the general-purpose linear PID controller, and enhances the tracking performance over a wide range of input. Numerical simulations and experimental results show the effectiveness of the fuzzy PID controller in comparison with the conventional PID controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1182-1184
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• 2001

This paper presents a neural network based self-tuning fuzzy PID control scheme for induction motor speed control. The PID controller is being widely used in industrial applications. When continuously used long time, the electric and mechanical parameters of induction motor change, degrading the performance of PID controller considerably. This paper re-analyzes the fuzzy controller as conventional PID controller structure, and proposes a neural network based self-tuning fuzzy PID controller whose scaling factors are adjusted automatically. Proposed scheme is simple in structure and computational burden is small. The simulation using Matlab/Simulink is performed to verify the effectiveness of the proposed scheme.

• 전자공학회논문지S
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• 제35S권1호
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• pp.60-67
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• 1998

In this paper, a gain scheduling method of PID controller is proposed using fuzzy logic for balancing control of an inverted pendulum. First, gains of PID controller are calculated using pole-placement technique for the linearized model of an inverted pendulum and these gains are modified by fuzzy logic throughout control operations. A PD controller is used by switching near the set-point to improve the performance. It is illustrated by simulations that the proposed hybrid fuzzy control method yidels smaller rising time and overshoot compared to the fixed-gain PID controller or fuzzy logic-based only PID controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2102-2104
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• 2001

This paper present the strategy of self-tuning nonlinear PID control using neural network. The nonlinear PID controller consists of a conventional PID controller and a neural network compensator. The neural network is trained by back-propagation algorithm. In this paper we propose modified back-propagation algorithm to improve learning speed. The results of simulation show the usefulness of the proposed scheme.