• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.367-371
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• 2007

Large capacity UPS and emergency generators are being installed and operated at the specific target of important electric facilities that need uninterruptible power supply by the method of countermeasure against power failure for the less reliable incoming power method. Recently, CTTS (Closed Transition Transfer Switch) is being used as uninterruptible power transfer switch at the Common sources of electricity, generator and multiple generators. In this paper, construction plans for uninterruptible power supply system has been suggested in which CTTS has been applied to the secondary of incoming power generator for reliable common dual system method. By briefing the construction of incoming power facilities, large capacity UPS, emergency generator installation space and investment saving effects can be achieved.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.64-70
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• 2010

High capacity UPS and emergency generators are commonly employed at facilities where power interruption is not allowed. Nowadays, combinations of existing commercial incoming power and an emergency generator or combination of multiple generators and CTTS(Closed Transition Transfer Switch) is adopted sometimes for more reliable power supply. In this paper, application of CTTS and STS(Static Transfer Switch) to dual-power line is suggested for highly reliable uninterruptible power. By realizing such a system, construction of incoming power facilities, installation of emergency generator and large capacity UPS can be omitted, through which saving of the installation space and corresponding capital investment can be expected.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1317-1320
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• 2014

In case of using three-phase induction motor in three-phase power system, if he deficiency happens in phase among three-phase, the motor will drive in an open phase state. As to the motor, the continuing operation is possible then, but the phenomenon that the power supply stops happening by the result of the overload electricity order on the healthy phase of two phases with a damage and activating the circuit breaker. Consequently, in order to overcome this problem in treatise accordingly. I propose an uninterruptible power supply which is able to prevent that the over current on the health phase through the restoration that in case happening open phase on the power line when driving the motor. Also, it is possible to supply power consecutively without interruption of electric power and we proved the performance and reliability through an experiment.

• Proceedings of the KIEE Conference
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• 2006.05a
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• pp.5-7
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• 2006

In this paper, developed a uninterruptible hotline tools and method for replacement of strain pole crossarm on overhead distribution line. For practical use of developed tools, following direct hot-line methods were proposed: 'Direct hot-lire method for replacement of pin pole crossarm', 'Direct hot-line method for alteration of crossarm' and 'Crossarm replacement method in uninterruptible cable displacement area'. These methods were proposed more simple and safe working on hotline job.

• Journal of information and communication convergence engineering
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• v.5 no.4
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• pp.362-368
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• 2007

A single-phase uninterruptible power supply system equipped with a superconducting magnet energy storage unit is proposed to achieve a simple circuit configuration and higher system reliability. It reduces a number of switching devices by applying a common-arm scheme. Removing some switches or substituting passive elements for active switches can increase the sophistication and reduces degree of freedom in control strategy. However, high-performance DSP controller can execute the complicated control task with no additional cost. Operational principles to normal, stored-energy, and bypass mode are discussed in detail. The validity of the proposed system is verified by experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.11
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• pp.100-105
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• 2014

In this paper, Uninterruptible Power Supply(UPS) Inverter system using Carrier Frequency Modulated PWM (CFM-PWM) is proposed to reduced harmonics and electromagnetic noise. Power conversion of UPS system is executed by the ON-OFF operation of semiconductor switching devices. However, this switching operation causes the surge and EMI which deteriorate the reliability of the UPS system. This Problems improved by Random PWM switching method. The simulation results of the proposed system was compared with the system using conventional method using Matlab/Simulink. The results show that the output voltage and current harmonics of the proposed UPS system significantly decreased and spread into wide band area by the proposed Carrier Frequency Modulated PWM(CFM-PWM) method based on the Space Vector Modulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.5
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• pp.61-66
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• 2013

In this paper, a control scheme with the capability of high efficiency, which is realized by predicting the conditions of a load power and an input power, is proposed for the uninterruptible power supply (UPS). Generally, on-line UPS system supplies a constant voltage and a constant frequency (CVCF). However, the efficiency of the On-line UPS system can be reduced due to the switching losses of semiconductor devices during the power conversion. The these losses are improved by the proposed smart UPS with the high efficiency drive system, which is realized by analysing and predicting the conditions of a load power and an input power.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.6
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• pp.535-542
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• 2017

This paper proposes a simple 3-level interleaved charger-discharger for the uninterruptible power supply (UPS) with various combinations of battery cells. The proposed converter not only improves charging and discharging efficiency, but also reduces the physical volume and the cost. Furthermore, the converter also offers the capability of the neutral point voltage, so that more stable operation can be obtained. In addition, the proposed converter significantly reduces the ripple current of the battery inductor, thereby providing an expected life extension of the battery. Experimental results for a 300kVA UPS prototype verify the validity of the proposed converter. The proposed charger-discharger is suitable for UPSs and energy storage systems (ESSs) with wide input battery voltage ranges.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.300-302
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• 1996

In this paper a new series-parallel compensated uninterruptible power supply is proposed. Its series compensator shapes input current to sinusoid. The power handled by series compensator is only a quarter of ratings. And parallel compensator delivers sinusoidal voltage to nonlinear load. The parallel compensator is backedup with battery. This system has capabilities of power line conditioner and backup power with reduced size.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.203-204
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• 2014

In this paper, single-phase uninterruptible power supply design method is presented. In this control scheme, input current, output current and output voltage are used. For voltage control PR controller is used and that for current controller is PI controller. The gains for controllers are sought by the classical method for determining gains. Throughout simulations the performance of single-phase UPS is verified.