• 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.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.3
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• pp.231-239
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• 2004

A new scheme to estimate the moment of inertia in the motor drive system in very low speed is proposed in this paper. The simple estimation scheme, which is usually used in most servo system for low speed operation, is sensitive to the variation of the machine parameter, especially the moment of inertia. To estimate the motor inertia value, Reduced-Order Extended Luenberger Observer (ROELO) is applied. The effectiveness of the proposed inertia identification method using the RORLO is verified by simulation and experiment.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2478-2480
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• 1999

In this paper, the authors propose a current control system for three phase PWM AC/DC converter without the source voltage sensors. The sinusoidal input current and unity effective power factor are realised based on the estimated source voltage in the controller. The estimation of source voltage is performed based on Luenberger observer using actual currents. The estimated source voltage is used to accomplish unity power factor. The proposed method is proved by simulations.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.9
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• pp.515-521
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• 2002

This paper presents the scheme that improves control responsibility and stability of the controlled-PM electromagnet levitation system with zero Power controller. A magnetically levitation system is used widely because friction can almost be disappeared. But it is difficult to control due to restraint of controllable area and nonlinear characteristics of electromagnetic force, which is proportioned to a square of the magnetic flux density and is in inverse proportion to a square of the air-gap. So, the application of observer theory in which the levitation system is considered to be a linear dynamic model has resulted in omitting the time dependence on mover's speed. Consequently, the performance of the observer is quite poor during transients. Therefore, this paper proposed the controlled-PM electro-magnetic levitation control method in which the variable load is estimated by using the reduced order extended luenverger observer and its system is controlled at a new zero power equilibrium air-gap position. It is also verified that the proposed control method improve the control performance through simulation and experiment.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.865-874
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• 2019

A controller for an underwater glider is presented. Considered underwater glider is a torpedo-shaped autonomous underwater vehicle installing adjustable buoyancy bag and movable battery in it. The controller is composed of an LQR controller to maintain zigzag vertical movement for gliding and two PD controllers to control elevator/rudder angles. The LQR controller controls the pumping speed into the buoyancy bag and the moving speed to locate the battery. One of the PD controller controls the elevator angle to assist the LQR controller, and the other controls the rudder angle to adjust the direction of the underwater glider. A reduced order Luenberger observer is adopted to estimates the center of gravity of the glider and the buoyancy mass that are essential but cannot be measured. Mathematical simulation using Matlab proved the validity of the proposed controller to obtain better performance than conventional LQR only controller under the influence of sea current.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.3
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• pp.100-105
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• 1984

The optimal Load-Frequency Control law is presented with the performance criterion which includes the changing rate of governor speed. The authors propose two controllers. One is a dynamic controller using the method of state augmentation and the other is a constant gain controller with use of the trace function lemma by Kleinman. For a more practical realization, a reduced-order Luenberger observer is applied in order to identify unmeasurable states and power demand. The control schemees presented here are tested through the model developed by Elgerd, and the usefulness is demonstrated.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.3
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• pp.116-124
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• 2002

Design and analysis of disturbance observer-based deadbeat control fur single-phase inverter applications are comprehensively presented in this paper. Load current can be estimated by disturbance observer, which is basically structured with the first order equation in this case and is regarded as a relatively simple method in comparison with conventional full-order Luenberger observer. Also, an inherent one-step delay problem appeared in the deadbeat control method is overcome by a simple prediction technique proposed. Output voltage dip is reduced by the feedforward control with the change rate of the estimated load current involved in the deadbeat current control loop. The proposed algorithms are verified by the respective simulation and experiment results.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1090-1092
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• 2003

A new scheme to estimate the moment of inertia in the motor drive system in very low speed is proposed in this paper. The simple speed estimation scheme, which is usually used in most servo system for low speed operation, is sensitive to the variation of the machine parameter, especially the moment of inertia. To estimate the motor inertia value, Reduced-Order Extended Luenberger Observer (ROELO) Is applied. The effectiveness of the proposed ROELO is applied by experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.610-616
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• 2008

This paper presents a new robust sensorless control system for high performance induction motor drives fed by a matrix converter with variable structure. The lumped disturbances such as parameter variation and load disturbance of the system are estimated by a variable structure approach based on model reference adaptive scheme. A Reduced Order Extended Luenberger Observer(ROELO) is also employed to bring better responses at the low speed operation. Experimental results are shown to illustrate the performance of the proposed system.