• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.390-393
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• 2007

The reliability as well as the power capability of the UPS system can be increased by replacing a single UPS unit with multiple small UPS units in parallel, resulting in a so-called module UPS. This module UPS system allows that a new module can be added or replaced while maintaining power to loads, which is a hot-swappable operation. In addition, it has desirable features such as ease of output power expandability, convenience of maintenance and repair, and high reliability. To realize the module UPS, load sharing without interconnection among parallel connecting modules as well as a small scale and lightweight topology is necessary. The frequency and voltage droop method is applied to parallel operation control to achieve load sharing. 5kVA modules are designed and implemented to confirm the effectiveness of the proposed approaches. Experimental results show that the module UPS system has a high power factor, a low distortion of output voltage and input current, hot-swappable operations and good load sharing characteristics.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.53 no.4
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• pp.190-194
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• 2004

In this paper, UPS, which is embedded in computer power supply, is developed against the poor utility power system. In the developed system, PIC16C54 is used as the main controller, and UPS system consists of micom control module, power failure detecting module, charging module, power module, synchronous transfer module, and GUI module. Additionally, GUI module consists of battery charging state unit, power operating unit and operating state unit. The effectiveness of the developed system has been verified by the experimental results.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.987-993
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• 2003

The module UPS can flexibly implement expansion of power system capacities. Furthermore, it can be used to build up the parallel redundant system to improve the reliability of power system operation. To realize the module UPS, load sharing without interconnection among parallel connecting modules as well as a small scale and lightweight topology is necessary. In this paper, the three-arm converter/inverter is compared with the general full-bridge and half-bridge topology from a practical point of view and chosen as the module UPS topology. The switching control approaches based on a pulse width modulation of the converter and inverter of the system are presented independently The frequency and voltage droop method is applied to parallel operation control to achieve load sharing. Two prototype 3kVA modules are designed and implemented to confirm the effectiveness of the proposed approaches. Experimental results show that the three-arm UPS system has a high power factor, a low distortion of output voltage and input current, and good load sharing characteristic.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.1
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• pp.44-51
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• 2003

The module UPS can flexibly implement expansion of power system capacities. Further-more, it can be used to build up the parallel redundant system to improve the reliability of power system operation. To realize the module UPS, load sharing without interconnection among parallel connecting modules as well as a small scale and lightweight topology is necessary. In this paper, the three-arm converter/inverter is compared with the general full-bridge and half-bridge topology from a practical point of view and chosen as the module UPS topology. The switching control approaches based on a pulse width modulation of the converter and inverter of the system are presented independently. The frequency and voltage droop method is applied to parallel operation control to achieve load sharing. Two prototype 3㎸A modules are designed and implemented to confirm the effectiveness of the pro-posed approaches. Experimental results show that the three-arm UPS system has a high power factor, a low distortion of output voltage and input current, and good load sharing characteristics.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2288-2291
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• 2004

In this paper, UPS, which is embedded in computer, is developed against the poor utility power system. In the developed system, PIC16C74A is used as the main controller, and UPS system consists of micom control module, power failure detecting module, charging module, power module, synchronous transfer module, and GUI module. Additionally, GUI module consists of battery charging state unit, power operating unit and operating state unit.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.461-462
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• 2014

This paper proposes parallel operation method of single phase UPS module considering the battery SOC. A master module performs output voltage control and current sharing algorithm considering battery SOC of each UPS modules. The slave modules control output current by current reference from master module. The applied parallel operation method is verified by the PSIM simulation.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.41-44
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• 1999

The main purpose of the UPS is to supply independent and stable power to connected equipment. In installing and operating the UPS system, songle module, three phase UPS in more benefit than multi module, songle phase UPS in the point of volume and cost. However, when supplying Rectifier with output power form three phase UPS, by connecting auto-transformer, occurred harmonic and ripple current makes output filter damaged and leads to nonlinear current coasted by unbalance load. Therefor, in this paper the aim of concentring compound-wound transformer and harmonic filter is supplying liner current by reducing harmonic and ripple current and improving unbalance in voltage and distortion in current wave.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.479-480
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• 2016

This paper introduces a master and slave control algorithm for parallel operation of UPS system. If each module of UPS system control the output voltage and filter inductor current in parallel operation, it occur unbalanced output power each module. To operate UPS system parallel, it need a algorithm that control output power of modules. A master and slave control algorithm is helpful to balance output power of modules by controlling output current. The effect of a master and slave control algorithm is proved by simulations.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.258-259
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• 2017

본 논문에서는 병렬 멀티-모듈 UPS 인버터의 출력 LC필터를 이용한 예측제어를 제안한다. 부하의 용량증가에 따라 단상 UPS 모듈을 병렬로 증가시켜 UPS 용량 증설하는 연구가 진행되고 있다. 이러한 UPS 시스템을 제어하기 위해 기존 제안하였던 전류 예측 제어에서는 PI 전압 제어로 인해 UPS 모드 절환 시 제한된 동적 반응(Dynamic response)을 갖는 단점이 있었다. 이러한 문제점을 보완하기 위해, 본 논문에서는 PI 전압제어를 전압 예측 제어로 대체함으로써 보다 빠른 동적 반응을 가질 수 있는 전압 및 전류 예측제어를 제안한다. 제안한 제어기법의 타당성은 수학적 분석 및 시뮬레이션을 통해 검증하였다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.67-68
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• 2015

본 논문에서는 멀티모듈 단상 UPS(Uninterruptible Power Supply) 시스템의 예측 제어기법을 제안한다. 제안한 예측 제어기법은 단상 UPS의 수학적 모델링을 통해 설계되었으며, 전류 예측제어를 통해 모드 절환 시 동특성을 향상시켰다. 제안하는 예측 제어기법은 PSIM 시뮬레이션을 통하여 검증하였다.