• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.600-604
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• 2000

In this paper authors proposed a new nonlinear rotor flux observer for rotor field oriented control of an induction motor which is designed based on theory of the extended Luenberger observer(ELO) one of a nonlinear state observer. The proposed rotor flux observer is derived from the 2 phase model of induction motor by the theory of ELO. The simulation results taken under the varying condition of rotor resistance and load torque show fast convergence of estimated rotor flux and high performance of IM drive system is achieved 표 experiment.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.2
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• pp.115-124
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• 2001

In this paper, authors propose a new nonlinear rotor flux observer for rotor field oriented control of an induction motor which is designed based on the extended Luenberger Observer theory. Extended Luenberger Observer requires minimal solution of nonlinear partial differential equation on its coordinate transformation and linearization needed on a nonlinear observer design in general. The proposed rotor flux observer is derived from the 2 phase model of induction motor on the orthogonal coordination and it has the reduce gain matrix. Simulation and experimentation were performed under the conventional indirect vector control and direct vector control with the proposed observer at different rotor resistance. Simulation results show that the convergence of the proposed observer is influenced by the chosen eigenvalues. Experimentation results on load operation show the direct vector control with the proposed observer is better than the indirect vector control to maintain the characteristics of the vector control.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.11
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• pp.1138-1144
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• 2011

This article deals with the problem of fault detection of a spacecraft's actuators. The authors introduce an extended unknown input observer for nonlinear systems. This is an extended form of unknown input observers which are used for linear systems. Since faults are not available, those are considered as unknown inputs. Unknown input observers can estimate states without full information of inputs if some conditions are satisfied. The authors suggest a continuous-time extended UIO (eUIO) and prove the convergence of state estimation errors. Since the dynamic equation of a spacecraft is nonlinear, an extended UIO can be applied. Three eUIOs are designed to monitor three reaction wheels. The moving averages of each eUIO's residuals are selected for decision logic. The proposed method is verified by numerical simulations.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.3
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• pp.173-179
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• 2004

A synthesis method of the reduced-order extended Luenberger observer (ROELO) and its design procedure for a nonlinear dynamic system are presented. This paper proposes a method to reduce the order of the observer and to ! elect the observer gain matrix. The proposed algorithm is applied for high performance induction motor drives without a speed sensor The simulation and experiment results show that the proposed ROELO provides both rotor flux and rotor speed estimation with good performance.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.3
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• pp.289-297
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• 2014

This paper proposed a novel high performance sensorless control scheme for IPMSM based on an extended nonlinear state observer. The gain-matrix of the observer has been derived by using state linearization method. Steady state errors in estimated rotor position and speed due to parameter inaccuracy have been analyzed, and an equivalent flux error is defined to represent the overall effect of parameter errors contributing to the wrong convergence of the estimated rotor speed as well as rotor position. Then, an online compensation strategy was proposed to limit the estimation errors in rotor position and speed. The effectiveness of the extended nonlinear state observer is validated through simulation and experimental test.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.963-969
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• 2002

Design method of a robust impedance control is proposed for the kinematically redundant manipulators. To achieve this objective, we first use the momentum feedback disturbance observer(MFDOB) scheme which can handle the nonlinear dynamics of a manipulator in Joint space. An extended task space formulation to describe the behaviors of task and null spaces of redundant manipulator is employed. Using the extended task space formulation and disturbance observer scheme, a robust impedance control method is designed. The performance of the proposed extended impedance controller is verified through experiments with a planar three links direct-drive manipulator.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1166-1176
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• 2017

Estimation errors of the rotor speed and position in sensorless control systems of Permanent Magnet Synchronous Motors (PMSM) will lead to low efficiency and dynamic-performance degradation. In this paper, a parallel-type extended nonlinear observer incorporating the nominal parameters is constructed in the stator-fixed reference frame, with rotor position, speed, and the load torque simultaneously estimated. The stability of the extended nonlinear observer is analyzed using the indirect Lyapunov's method, and observer gains are selected according to the transfer functions of the speed and position estimators. Taking into account the parameter inaccuracies issue, explicit estimation error equations are derived based on the error dynamics of the closed-loop sensorless control system. An equivalent flux error is defined to represent the back Electromotive Force (EMF) error caused by the inaccurate motor parameters, and a compensation strategy is designed to suppress the estimation errors. The effectiveness of the proposed method has been validated through simulation and experimental results.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.3 s.22
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• pp.92-100
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• 2005

The objective of this paper is to design a sliding mode controller of an electro-mechanical fin actuation system using extended reducer-observer(ERO) which is used in order to estimate the velocity. The employed observer enables proper estimation of the plant state variables, even in the case of the constant or slow varying load torque disturbances. The effectiveness of this control scheme is verified by comparison with a PID control through a series of simulation studies. The simulation results show that the sliding mode control designed with the ERO gives good control performances.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.11
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• pp.760-767
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• 2004

In this paper, we propose sufficient conditions under which nonlinear systems can be transformed into nonlinear observer canonical form in the extended state space by virtue of dynamic system extension. The proposed scheme weakens two major restrictions of observer error linearization technique. Once a nonlinear system is transformed into nonlinear observer canonical form using dynamic system extension, a state observer can be easily designed. Two illustrative examples are included in order to compare the proposed scheme and observer error linearization method.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.63.1-63
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• 2002

In this work a new design approach of nonlinear control is presented based on a extended observer for the estimation and compensation on a dynamics system and the estimates are compared to the effects from neual nets. Simulation's results show that this method tells a good alternative to the standard ways.