• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.95-98
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• 1995

In this paper, an unknown-input proportional integral (PI) observer is presented and its applicability to the design of exact loop transfer recovery (Exact LTR) is shown. First, a sufficient condition for the PI observer to estimate the states of systems without knowledge of unknown input is derived. A simple existence condition of the observer is given. Under the conditions, the Exact LTR with specified observer's poles is achieved by the unknown-input PI observer.

• 전기학회논문지
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• 제60권5호
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• pp.1011-1016
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• 2011

This paper presents a robust current controller for a surface-mounted permanent magnet synchronous motor(SPMSM) by using a PI observer. The decoupling PI(proportional-integral) controller combined with an additional feed-forward compensation has been used for the current controller. The classical feed-forward compensation using velocity information and system parameters is not expected to achieve a robust performance against parameter uncertainties. This paper has adopted a PI observer for the feed-forward compensation to cope with parameter uncertainties without using velocity information. A simple PI observer has been designed to compensate the disturbances that represent velocity coupled terms and parameter uncertainties. Experimental results as well as computer simulations with 630W SPMSM confirm that the proposed approach can deal with the effects of the disturbance and improve the control performance.

• 전기학회논문지
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• 제66권12호
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• pp.1732-1739
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• 2017

This paper presents a sensorless vector control algorithm of closed loop Gopinath flux observer to enhance the robustness at low speed by switching P/PI mode. Closed loop Gopinath flux observer has the problem in sensorless vector control of induction motor at low speed. This paper solves the problem using the characteristic function of closed loop Gopinath flux observer. P mode shows better performance than PI mode under the cut-off frequency of observer. But P mode always has a flux error due to DC offset, so this paper combines P mode and PI mode. This algorithm shows good performance over wide speed range. The performance has been confirmed through computer simulations using MATLAB SIMULINK and experiments.

• Transactions on Control, Automation and Systems Engineering
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• 제3권2호
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• pp.77-82
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• 2001

This paper deals with a fault detection algorithm for linear descriptor systems via unknown input PI observer. An unknown input PI observer is presented and its realization conditions is proposed by using the rank condition of system matrices. From the characteristics of unknown input PI observer, the states of system with unknown inputs are estimated and the occurrences of fault are detected, and its magnitudes are estimated easily by using integrated output estimation error under the step faults. Finally, a numerical example is given to verify the effectiveness of the proposed fault detection algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.452-452
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• 2000

This paper deals with a fault detection algorithm for linear descriptor systems via unknown input PI observer. An unknown input PI observer is presented and its realization conditions is proposed by using the rank condition of system matrices. From the characteristics of unknown input PI observer, the states of system with unknown inputs are estimated and the magnitude of failures are detected and isolated easily by using integrated output error under the step failures. Finally, a numerical example is given to verify the effectiveness of the proposed algorithm.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.363-367
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• 1996

The robustness issues in fault detection and isolation(FDI) have received considerable attenuation in recent years, due to the increasing demand for safe and reliable operation of uncertain and complex dynamic systems. The aim of this paper is to present the FDI method by using proportional integral(PI) observer and unknown input observer(UIO) under the faults of actuators and sensors. Due to this simple residual generator, the PI observer can easily detect the both faults of actuator and sensor. A simulation results show the effectiveness of this methods.

• 전력전자학회논문지
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• 제20권2호
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• pp.175-181
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• 2015

In this study, a lithium polymer battery (LiPB) is simply expressed by a primary RC equivalent model. The PI state observer is designed in Matlab/Simulink. The non-linear relationship with the OCV-SOC is represented to be linearized with 0.1 pu intervals by using battery parameters obtained by constant-current pulse discharge. A state equation is configured based on battery parameters. The state equation, which applied Peukert's law, can estimate SOC more accurately. SOC estimation capability was analyzed by utilizing reduced Federal Test Procedure (FTP-72) current profile and using a bi-directional DC-DC converter at temperature ($25^{\circ}C$). The PI state observer, which is designed in this study, indicated a SOC estimation error rate of ${\pm}2%$ in any of the initial SOC states. The PI state observer confirms a strong SOC estimation performance despite disturbances, such as modeling errors and noise.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.125-130
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• 1998

This paper presents a speed control for ultrasonic motors using a PI controller and disturbance torque observer. Since the PI gains and the observer's poles are generally fixed, the control performance deteriorates when the driving conditions vary much. Therefore, we propose the speed control scheme that the PI gains and the observer's poles are adjusted on-line in accordance with the speed ripple using fuzzy reasoning.

• 한국전자통신학회논문지
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• 제16권3호
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• pp.511-518
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• 2021

전동기의 좋은 추종 성능을 얻기 위해서는 외란 관측기가 포함되어 외란에 대응할 수 있는 제어기를 설계하는 것이 필요하다. 전동기의 외란 관측기는 1차 저역통과 필터를 기반으로 부하 토크과 역기전압을 추정하도록 설계하였다. 외란 관측기와 제어기의 상호관계를 비교하고, 개선된 제어 성능을 얻기 위하여 PI 제어기와 IP 제어기를 설계하였다. 설계된 관측기와 제어기의 성능을 확인하고자 120 [W]급의 BLDC 전동기에 적용하였다. 그 결과 오버슈트가 줄어들며, 정상상태 오차가 영으로 수렴하는 것을 확인할 수 있다.

• 한국정밀공학회지
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• 제13권7호
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• pp.133-139
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• 1996

전형적인 상태 관측기에서는, 외란이 시스템 입력에 가해지는 경우 시스템의 상태 추정이 불가능하다. 이러한 상태관측 문제에 대한 한가지 대책법으로서 비례적분(PI) 관측기가 제안되어 스텝외란의 소거에 대한 유효성이 밝혀져 로바스트 제어기 설계에 대한 응용으로서 널리 연구가 행해져 왔다. 그러나, 미지입력에 대한 PE 관측기 설계는 여전히 문제로 남아 있다. 이 논문에서는 미지입력 PI 관측기의 설계법을 제안하고, 이에 대한 응용으로서 완전 LTR을 실현할 수 있는 결과를 보인다. 먼저, 입력의 정보없이 시스템의 상태를 추정할 수 있는 미지입력 PI 관측기의 충분조건을 제안하고, PE 관측기의 설계에 요구되는 필요충분조건을 보인다. 이러한 조건은 완전 LTR의 실현을 위한 직접적인 요구조건임을 보인다. 따라서, 완전 LTR을 달성하면서 지정한 관측기의 극을 지니는 PI 관측기 설계가 가능하다.