• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.2
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• pp.309-313
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• 2001

In this paper, a multifunctional three-phase electronic step-down transformer with output voltage stabilization characteristics is presented for custom power applications. The proposed electronic transformer has some advantages and features as follows: 1) It has 40 % weights lighter than that of commercial magnetic transformer, 2) It has output voltage stabilization characteristic with regulated output voltage over input variations, 3) It cab be operated as circuit breaker in the case of emergency, 4) It can be operated with so called soft starting function. Moreover, the electronic transformer may have stand-by power cutoff function and act as distortion compensator. This paper show the circuit diagram and present its features through various PSPICE simulations.

• Journal of the Korean Institute of Intelligent Systems
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• v.8 no.2
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• pp.117-127
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• 1998

Power systems have uncertain dynamics due to a variety of effects such as lightning, severe storms and equipment failures. The variation of the effective reactance of a transmission line due to a fault is an example of uncertainty in power system dynamics. Hence, a robust controller to cope with these uncertainties is needed. Recently, fuzzy controllers are becoming quite popular for robust control due to its potential of dealing with uncertain systems. Thus in this paper we design an adaptive fuzzy controller based on an input-output linearization approach for the transient stabilization and voltage regulation of a power system under a sudden fault. Also this paper proposes a fuzzy system that estimates the upper bound of uncertain term in the system dynamics to guarantee the Lyapunov stability. Simulation results show that good performance is achieved by the proposed controller.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.665-670
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• 2005

This paper introduces the propulsion system(Motor Block) stabilization test result for Korean High Speed Railway(HSR). The developed propulsion system using high power semiconductor, IGCT(Integrated Gate Commutated Thyristor) consists of two PWM converter and VVVF inverter. In this paper, overall configuration of propulsion system is briefly described and stabilization tests are made to verify the developed propulsion system. The presented test results shows beatless control method of inverter output current at the 200km/h and performance test of BCH.

• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.470-477
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• 2022

EOTS for drones is showing another aspect of market expansion in detection and recognition areas previously occupied by artificial satellites. The two-axis EOTS for drones controls the vibration or disturbance caused by the drone during the mission so that EOTS can accurately recognize the goal. Vibration generated by drones is transmitted to EOTS. Therefore, it is essential to develop a stabilization controller that attenuates vibrations transmitted from drones so that EOTS can maintain the viewing angle. Therefore, it is necessary to standardize drone disturbance and secure the performance of EOTS disturbance attenuation controller optimized for disturbance level through this. In this paper, a method of standardizing drone disturbance applied to EOTS is studied, through which EOTS controller simulation is performed and stabilization controller shape is selected and designed.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.115-124
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• 2008

The purpose of this study was to know influenced on the change of Oswestry back pain disability index(OBPDI), isometric muscle power(IMP), muscular activation with chronic low back pain(CLBP) patients after Trunk Stabilization Exercise. Intervention was provided 6 weeks(5 days a week). Muscular activation was measured during IMP(Muscles : transversus abdominis : TA, internal obliqus : IO, external obliqus : EO, rectus abdominis : RA and erector spinae: ES). The results were as follows. 1. OBPDI about the MBE and the SE groups had effective decrease pain and disability. 2. IMP of intervention after the MBE and the SE groups had effective improve muscle power. 3. Muscle activation during IMP of intervention after was : TA, IO, RA had increase in the MBE and the SE groups. EO muscle activation during IMP of intervention after had increase only MBE groups. This shows that the MBE and the SE groups had effective increase because it has effective improve muscle power. Therefore, this study shows ￡hat trunk stabilization exercise program influenced on the change of OBPDI, IMP, muscular activation with CLBP patients.

• Journal of Power Electronics
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• v.9 no.6
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• pp.884-891
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• 2009

An address voltage stabilization circuit for the single-side driving (SSD) method for AC plasma display panels (PDP) is proposed. The single-side driving method, which eliminates a common sustaining driver, uses only two electrodes in a three electrode AC PDP structure. The high-impedance (Hi-Z) mode operation of the data drive ICs during the sustaining period is needed for surface gas-discharge without misfiring in the SSD method but it produces the problem that the address voltage increases up to the breakdown voltage. The proposed circuit based on a flyback converter can stabilize the address voltage under the breakdown voltage and provide better surface gas-discharge performance without any misfiring in the SSD scheme.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.4
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• pp.240-246
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• 2018

In this paper, a sensorless V/f control based on maximum torque per ampere (MTPA) operation for PMSMs is proposed. Given that the MTPA operation is not considered in the conventional sensorless V/f control, efficient PMSM drives cannot be achieved. Therefore, this paper proposes an improved technique based on the d-axis current control to enable the MTPA operation in the V/f control for PMSMs. A stabilization technique is also proposed to improve the dynamic characteristics and stability against load variation. The effectiveness of the proposed technique is verified by conducting experiments with a 250 W SPMSM for driving a blower.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.226-228
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• 2005

This paper deals with power system stabilization problem using a network control system in which the control is applied through a communication channel in feedback form. Analysis and synthesis issues are investigated by modeling the packet delivery characteristics of the network as a Bernoulli random variable, which is described by a two state Markov chain. This model assumption yields an overall system which is described by a discrete-time Markov jump linear system. These employ the norm to measure the performance of the system, and they compute the norm via a necessary and sufficient matrix inequality condition.

• Journal of the Korean Institute of Intelligent Systems
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• v.6 no.3
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• pp.63-72
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• 1996

In this paper, we propose a design technique for a neural network controller and apply it to power system stabilization. Using a learning algorithm of error back propagation that accepts error and change of error as inputs, the momentum learning technique is used by which reduction of learning time is possible for real time control. The related simulation results show that the proposed control techinque is more powerful than the conventional ones for dynamic responses.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.83-85
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• 1995

A technique for power system' stabilization is presented using the variable structure control theory. The selection problem of the proper switching vector is very important subject for a design of the variable structure controller. In this paper, the switching vector is selected by desired eigenvalues allocation. and these desired eigenvalues are determined by eigenvalue assignment. Simulation results show that eigenvalue allocation variable structure stabilizer yields better dynamic performance than the others (conventional PSS, optimal linear stabilizer) and is robust to wide variations of the system parameters.