• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1954-1956
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• 1997

In this paper, a variable structure current control scheme for field-oriented induction motor drive is presented. The current controller based on space voltage vector PWM scheme consists of feedforward, decouple and variable structure control. The proposed current controller tracks reference value quickly, has robust property against parameter variation and disturbance, reduces switching frequency and improves performance of induction motor drive. Finally, the proposed current controller is verified by digital simulation

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.17-20
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• 1996

An adaptive current control scheme of a permanent magnet (PM) synchronous motor with the simultaneous estimation of the magnitude of the flux linkage and stator resistance is proposed. The adaptive parameter estimation is achieved by a model reference adaptive system (MRAS) technique. The adaptive laws are derived by the Popov's hyperstability theory and the positivity concept. The predictive control scheme is employed for the current controller with the estimated parameters. The robustness of the proposed current control scheme is compared with the conventional one through the computer simulations.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.97-100
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• 1997

A new control method for the robust position control of a brushless DC(BLDC) motor using the asymptotically stable adaptive load torque observer is presented. A precision position control is obtained for the BLDC motor system approximately linearized using the field-orientation method. And the application of the load torque observer is published in [1] using fixed gain. However, the flux linkage is not exactly known for a load torque observer. Therefore, a model reference adaptive observer is considered to overcome the problem of the unknown parameter in this paper. And stability analysis is carried out using Liapunov stability theorem. As a result, asymptotically stable observer gain can be obtained without affecting the overall system response. The load disturbance detected by the asymptotically stable adaptive observer is compensated by feedforwarding the equivalent current having the fast response.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09b
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• pp.141-144
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• 2003

A composite adaptive dual fuzzy controller combining the approximate mathematical model, linguistic model description, linguistic control rules and identification modeling error into a single adaptive fuzzy controller is developed for a nonlinear system. It ensures the system output tracks the desired reference value and excites the plant sufficiently for accelerating the parameter estimation process so that the control performances are greatly improved. Using the Lyapunov synthesis approach, proposed controller is analyzed and simulation results verify the effectiveness of the proposed control algorithm.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.469-474
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• 2002

The Field Robot means the machinery applied for outdoor tasks in construction, agriculture and undersea etc. In this study, to field-robotize a hydraulic excavator that is mostly used in construction working, we have developed an automatic excavation system and adaptive control system. A model- reference adaptive controller has been designed on the model that is obtained through off-line System Identification. It is illustrated by computer simulations that the proposed control system gives good performances in the trajectory tracking control and adaptation to parameter variation.

• Journal of Energy Engineering
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• v.12 no.4
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• pp.281-288
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• 2003

The MATRA-LMR code has been developed based on a subchannel analysis method for LMR (Liquid Metal Reactor) core subassembly thermal hydraulic design and analysis. The code was improved to allow a seven assembly calculation and can account for inter-assembly heat transfer based on a lumped parameter model. This paper describes the main modifications and improvements of the code and shows reference calculation results which compared single assembly calculation with seven assembly calculation cased for driver and blanket subassemblies of the KALIMER 150 MWe breakeven conceptual design core. KAL- IMER is a pool-type sodium cooled reactor with a thermal output of 392.0 MWth, which have inherently safe, environmentally friendly, proliferation-resistant and economically viable reactor concepts.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.9
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• pp.33-43
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• 2011

Since the fuzzy neural network(FNN) is universal approximators, the development of FNN control systems have also grown rapidly to deal with non-linearities and uncertainties. However, the major drawback of the existing FNNs is that their processor is limited to static problems due to their feedforward network structure. This paper proposes the recurrent FNN(RFNN) for high performance and robust control of SynRM. RFNN is applied to speed controller for SynRM drive and model reference adaptive fuzzy controller(MFC) that combine adaptive fuzzy learning controller(AFLC) and fuzzy logic control(FLC), is applied to current controller. Also, this paper proposes speed estimation algorithm using artificial neural network(ANN). The proposed method is analyzed and compared to conventional PI and FNN controller in various operating condition such as parameter variation, steady and transient states etc.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.830-831
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• 2011

The paper makes an investigation on a speed and stator flux linkage estimator for permanent magnet synchronous motor (PMSM) sensorless drives using the technology of model reference adaptive system (MRAS). The designed estimator including two models and two adaptive estimating laws is proved to be stable by the Popov hyper-stability theory. The speed, the stator flux linkage and the resistance are estimated accurately by the proposed estimator while overcoming the shortcoming of the traditional one. The experiment results demonstrate its effectiveness.

• Korean Management Science Review
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• v.11 no.2
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• pp.147-159
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• 1994

The problems of determining appropriate QOS(Quality of service) requirements of B-ISDN services and finding the corresponding NP(Network Performance) values satisfying the given QOS requirements are very important problems which are directly related to the successful operation of the ATM network, but have not been studied with enough attention yet. The QOS(NP) parameter definition, QOS measurements, and QOS managements are three major problems that should be solved. In this paper, we first introduce the basic concepts of QOS and NP and their relationships. Then we discuss more comprehensive concepts of QOS based on the layered structure of ATM services and the reference time, which can provide a systematic approach for QOS and NP mapping problems. We also provide examples of determining basic QOS(NP) parameters in the ATM layer and a specific example of QOS mapping based on the file transfer in ATM. The results of this paper can be used to establish the comprehensive QOS management model.

• Journal of Pharmaceutical Investigation
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• v.19 no.4
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• pp.191-194
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• 1989

Bioequivalence test of $Asthcontin^{\circledR}$ tablet, a commercial slow-release theophylline (TP) dosage form, was performed using $Slo-bid^{\circledR}$ capsule as the reference. Since it has been confirmed that the saliva concentration of TP is closely correlated with the plasma concentration in man, the area under the saliva concentration-time curve was used as a bioavailability parameter. The statistical analysis showed that the two dosage forms are equivalent in bioavailability estimating from the saliva concentration. The results supported that the use of soliva as a test sample provides simple and easy techniques for bioequivalence tests of TP-containing dosage forms.