• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2182-2184
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• 2004

This paper presents a systematic and straightforward fault estimation approach for process fault detection. isolation and accommodation. The approach includes the design of a reduced-order observer and an algebraic-fault estimator. The observer is designed for an unknown input and fault-free system, which is obtained by coordinate transformations of original systems with unknown inputs and faults. The observer information is devoted to- the fault estimation for fault detection and isolation. The fault estimates can be used to form an additional control input to accommodate the fault. The suggested scheme is verified through simulation studies performed on the control of a vertical takeoff and landing (VTOL) aircraft in the vertical plane.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.4
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• pp.319-323
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• 2002

In this paper, we consider the track-following control problem in the optical data storage systems in the presence of the eccentricity. The eccentricity results in the radial deviation of the objective lens so that it degrades the reliability of the data decoding system. To cope with the eccentricity, an adaptive disturbance compensation technique is newly proposed in the time domain based on a disturbance observer of reduced order, which effectively estimates the low frequency components of the disturbance. The proposed compensator is simply added to the conventional feedback control. The error dynamics of the observer and the sensitivity analysis are given to illustrate the effectiveness of the proposed approach. Finally, through experiments in an optical storage system, the feasibility of the proposed approach is verified.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.4
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• pp.566-574
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• 2013

In this paper, direct power control system for three-phase PFC AC/DC converter without the source voltage sensors is proposed. The sinusoidal input current and unity effective power factor are realised based on the estimated flux in the observer. Both active and reactive power calculated using estimated flux. The estimation of flux is performed based on the reduced-order virtual flux observer using the actual currents and the command control voltage. Moreover, source voltage sensors are replaced by a estimated flux. DC output voltage has been compensated by DC output ripple voltage estimation algorithm. The active and reactive powers estimation are performed based on the estimated flux and Phase angle. The proposed algorithm is verified through simulation and experiment.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1185-1201
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• 2018

This paper presents a sensorless direct torque control (DTC) combined with sliding mode approach (SM) and space vector modulation (SVM) to achieve mainly a high performance and reduce torque and flux ripples of a parallel-connected two five-phase permanent magnet synchronous machine (PMSM) drive system. In order to increase the proposed drive robustness and decrease its complexity and cost, the rotor speeds, rotor positions, fluxes as well as torques are estimated by using a sliding mode observer (SMO) scheme. The effectiveness of the proposed sliding mode observer in conjunction with the sliding mode control based DTC is confirmed through the application of different load torques for wide speed range operation. Comparison between sliding mode control and proportional integral (PI) control based DTC of the proposed two-motor drive is provided. The obtained speeds, torques and fluxes responses follow their references; even in low and reverse speed operations, load torques changes, and machines parameters variations. Simulation results confirm also that, the ripples of the torques and fluxes are reduced more than 3.33% and 16.66 %, respectively, and the speed overshoots and speed drops are reduced about 99.85% and 92.24%, respectively.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.3
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• pp.47-56
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• 1999

제한된 출력 즉 오차 측정된 출력 값만을 사용하여 원하는 목표치에 도달하도록 하는 제어 문제를 푸는데 많은 연구가 진행되어 왔다. 종종 그러한 제어기를 설계할 때 해를 구하기 어려운 Non Linear Two Point Boundary Value Problem에 직면하게 된다. 특히 Reduced order 추정자 알고리즘은 백색 잡음에 의하여 영향을 받은 선형 시스템의 측정된 상태 뿐 만 아니라 보조 상태를 추정하기 위하여 개발되었다. 추정자를 설계할 때 상태는 무편향성이고 추정자의 편차는 추정자 및 추정상태와 공통되는 상태에 대한 모든 출력의 subspace에 수직이 된다. 특히 reduced order에서의 필터 성능은 full order에서의 필터 성능에 대해 suboptimal 이지만 상응한 Riccati equation을 푸는데 계산시간이 줄고 memory사용이 적은 이점이 있다. 본 논문에서는 Kronecker algebra와 선택행렬을 이용하여 Non Linear Two Point Boundary Value Problem을 Linear Two Point Boundary Value Problem으로 변환시켜 부수적으로 수반되는 대수적인 Riccati equation을 유도함으로써 문제를 쉽게 해결하는데 있다.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1035-1047
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• 2015

Starting from a new dynamic system description novel synchronous machine deterministic observers are proposed. Reduced and full order adaptive observer variations are presented. Based on the feedback linearization control law and the use of deterministic observer a novel control system is built. It meets the requirements of high performance tracking system. Adaptivity to stator and rotor resistance and the torque sensorless application is included. The comparison of the proposed novel control with conventional linear and nonlinear control systems is discussed. The given simulational study includes complete drive system integration.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.142-145
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• 2002

A new scheme to estimate machine inertia in low speed is proposed in this paper. It is necessary to consider the machine parameter of low speed instantaneous observer to precise control in servo system, which has frequent load variation and speed change. To estimate machine parameter, especially the moment of inertia, Reduced-Order Extended Luenberger Observer (ROELO) is applied. The effectiveness of the proposed ROELO is showed by simulation.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1124-1127
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• 2003

This paper proposes a sensorless vector control of interior permanent magnet synchronous motor(IPMSM) using a Luenberger observer. Linearizeng the motor model, we can construct the linear reduced order observer for estimating rotor position and disturbance torque. The validity of the proposed scheme is confirmed by various response characteristics.

• Journal of the Semiconductor & Display Technology
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• v.23 no.2
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• pp.92-99
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• 2024

As semiconductor processes require several nanometers precision, the importance of motor control is increasing in semiconductor equipment. Due to unpredictable uncertainties such as friction and mechanical vibrations achieving precise position control in semiconductor processes is challenging. The internal model principle-based controller is a control technique that ensures robust steady-state performance by incorporating a model of the reference and disturbance. The disturbance observer-based controller is a prominent robust control technique implemented to cope with various nonlinearities and uncertainties. Provided that the two controllers can be designed to exhibit equivalent performance under certain conditions, this paper demonstrates through experiments that they yield identical results for the case of a BLDC position control problem. The experimental results also indicate that they can offer enhanced robustness compared with the conventional PID controller in the presence of a time-varying disturbance.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.307-308
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• 2007

In general, most physical systems are complex, highly non-linearity, affected by disturbance, incomplete knowledge, and even interactive change with the operating points. To solve this problem, the research of modem control theory and controller is proceeding. Before appling the proposed controller to the real system, however, it needs an apparatus which can verify the proposed controller for being not damaged the plant. In this paper, therefore, a RCGA-based PI-type state feedback controller using reduced-order observer is implemented and applied to the seesaw system and a series of simulation are carried out to verify the effectiveness of the control system.