• 전력전자학회논문지
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• 제13권2호
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• pp.145-151
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• 2008

본 논문에서는 계통 전압이 불평형인 경우에 정확한 위상각을 검출할 수 있는 정상분 전압 관측기를 이용한 PLL(Phase Locked Loop) 방법을 제안한다. 제안된 PLL 방법은 기존의 전역 통과 필터(APF, All Pass Filter)를 이용하여 불평형 전원전압으로부터 정상분 전압을 구하는 것과는 달리 전차원 상태관측기를 사용함으로써 불평형사고 발생 시 추정위상각의 과도상태 응답특성을 개선하였다. 기존의 정상분 전압 추출 PLL 방법과 본 논문에서 제안된 PLL 방법의 성능을 비교하기 위해, 전원단 전압에 불평형 사고 발생시 위상각을 검출하는 실험을 하였고, 이를 통해 기존의 전역 통과 필터를 이용한 정상분 전압 추출 PLL 방법보다 제안된 전차원 상태관측기를 이용한 정상분 전압 추출 PLL 방법의 과도상태 응답특성이 개선됨을 입증하였다.

• 대한임베디드공학회논문지
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• 제12권5호
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• pp.311-318
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• 2017

A reduced order observer is developed for depth control of a hybrid underwater glider which combines the good aspects of a conventional autonomous underwater vehicle and a underwater glider. State variables include the center of gravity of the robot and the weight of the buoyancy bag, which can not be directly measured. By using the mathematical model and available information such as directional velocities, accelerations, and attitudes, we developed a Luenberger's reduced order observer to estimate the center of gravity and the buoyancy weight. By simulations using Matlab/Simulink, the efficiency of the proposed observer is shown, where a LQR controller using full state variables is adopted as a depth controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.967-969
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• 1998

In this paper, the proposed controller is obtained by combining the nonlinear feedback linearization-sliding mode controller (NFL-SMC) with the full order observer (FOO) and eliminates the need to measure all the state variables in the conventional NFL-SMC.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권4호
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• pp.246-255
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• 2000

This paper deals with a novel full digital control method of the three-phase PWM inverter for UPS. The voltage and current of output filter capacitor as state variables are the feedback control input. In addition, a double deadbeat control consisting of a d-q current minor loop and a d-q voltage major loop, both with precise decoupling, have been developed. The switching pulse width modulation based on SVM is adopted so that the capacitor current should be exactly equal to its reference current. In order to compensate the calculation time delay, the predictive control is achieved by the current·voltage observer. The load prediction is used to compensate the load disturbance by disturbance observer with deadbeat response. The experimental results show that the proposed system offers an output voltage with THD less than 2% at a full nonlinear load.

• 전기의세계
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• 제30권12호
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• pp.822-831
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• 1981

Many different schemes of the adaptive observer and controller have been developed for both continuous and discrete systems. In this paper we have presented a new scheme of the reduced order adaptive observer for the single input discrete linear time invariant plant. The output equation of the plant, is transformed into the bilinear form in terms of system parameters and the states of the state variable filters. Using the plant output equation the discrete implicit adaptive observer based on the similar philosophy to Nuyan and Carroll is derived and the parameter adaptation algorithm is derived based on the exponentially weighted least square method. The adaptive model following control system is also constructed according to the proposed observer scheme. The proposed observer and controller are rather than simple structure and have a fast adaptive algorithm, so it may be expected that the scheme is suitable to the practical application of control system design. The effectiveness of the algorithm and structure is illustrated by the computer simulation of a third order system. The simulation results show that the convergence speed is proportinal to the increasing of weighting factor alpha, and that the full order and reduced order observer have similar convergence characteristics.

• Journal of Advanced Marine Engineering and Technology
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• 제25권1호
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• pp.162-170
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• 2001

This paper presents a scheme for designing a fuzzy model-bsaed state observer for nonlinear system. For this scheme, a Tagaki-Sugeno type fuzzy model whose consequent part is of the state space form is obtained. In describes the locally linear input/output relationship of a system. The parameters of the fuzzy model are adjusted using a genetic algorithm. Then. fuzzy full-order and reduced-order state observers are designed based on the fuzzy model. A set of simulation works is carried out to demonstrate the effectiveness of the proposed scheme.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1171-1173
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• 1997

This paper presents the sliding mode observer-model following(SMO-MF) power system stabilizer(PSS) for unmeasurable plant state variables. This SMO-MF PSS can be obtained by combining the sliding mode-model following(SM-MF) including closed-loop feedback(CLF) with the linear foil-order observer(LFOO).

• Journal of international Conference on Electrical Machines and Systems
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• 제3권3호
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• pp.252-255
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• 2014

In the case of long-stator linear drives, unlike rotative drives for which speed or position sensors are a single unit attached to the shaft, these sensors extend along the guideway. The position signal transmitted from maglev vehicle can't meet the need of the real-time propulsion control. In this paper the position estimator for propulsion inverter driving long stator linear synchronous motor (LSLSM) in high speed maglev train is proposed. In order to get the higher resolution of the position information transmitted from vehicle, Full order state observer is proposed for position estimator.

• 조명전기설비학회논문지
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• 제19권1호
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• pp.70-79
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• 2005

본 논문은 축소차원 상태방정식을 사용한 전차원 관측기를 이용하여 저속도 영역에서의 운전 성능 개선방법을 제안하였다. 축소차원 상태방정식을 사용한 전차원 관측기는 간단한 모터속도 및 외란토크 관측기이다. 제안한 알고리즘은 약 1.9[rpm]의 저속도에서 매우 안정적인 결과를 보였다. 모터구동 시스템에서 외란토크는 저속도 영역에서 속도제어 성능을 저하시킨다. 제안한 알고리즘은 모터속도와 외란토크를 모두 추정한다. 추정된 외란 토크는 속도제어기의 출력에 전향보상 값으로 사용되며, 그 결과 저속도 영역(1.9rpm)에서 부하토크 응답특성이 향상된 것을 확인하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권10호
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• pp.575-582
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• 2003

A new FDOs (fault diagnostic observers) and the residual generation schemes using the FDOs are suggested for the process fault detection and isolation of linear (control) systems. The design method of the FDO is described, first, for the full measurement systems. Then it is extended for the systems with unmeasurable state variables. An unknown input observer is proposed and applied for the extension. The size of the observer bank may be the smallest, specially in full measurement systems, because the order of the proposed FDO is very low. In spite of the simplicity, the scheme provides the same information for the detection and isolation of the anticipated faults as the conventional multiple observer based schemes. The residuals may be structured so that fault isolation can be performed by pre-selected logic. An FDIS using the proposed scheme is constructed for the model of the four-tank system. Simulation results show the practical feasibility of the proposed scheme.