• 한국산학기술학회논문지
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• 제6권6호
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• pp.491-496
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• 2005

본 논문에서는 일명 델타변환 무정전전원장치(UPS)로서 알려져 있는 3상 라인 인터랙티브 UPS 시스템의 성능 시험에 대해서 다루고 있다. 델타변환 UPS는 종래의 단일 변환 라인 인터랙티브 UPS 시스템에서 직렬 인덕터를 제거하고 직렬 및 병렬 PWM(Pulse Width Modulation) 컨버터를 사용하는 새로운 라인 인터랙티브 UPS 시스템으로 전원 전류를 직접 제어함으로써 UPS 시스템의 입출력 특성들이 상당히 개선되는 것으로 알려져 있다. 여기서는 UPS 시스템의 성능 시험에서 중요한 내용들인 부하시험, 정전/복전시험, 동기절체 시험 등에 대한 결과들을 제시하고 델타변환 UPS 시스템에 대한 전반적인 평가를 한다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1991년도 추계학술발표회논문집
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• pp.80-83
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• 1991

The need of UPS (Uninterruptible Power Sup-ply) system is dramatically increasing with the increased use of computers, telecommunica-tion system, building automation system, and office automation system in office buildings. The consequence of the power failure is very disas trous in intelligent office buil-dings. Thus, the nucessity of large scale UPS system with generations of large scale UPS system with generator is increasing. In this study, the configurations of large scale UPS system are reviewed and analyzed. The design guide and technical considerations of high reliability system are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.437-439
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• 1996

In this paper, an UPS system using high-frequency link AC to DC converter is Proposed. The AC to DC converter has sinusoidal input current and high power factor. In this UPS system, the waveform of the output voltage has smaller harmonic contents than those of a conventional UPS system. In this paper, an operating principle of the system is presented. This new control technique of the UPS system is capable of providing a wide range regulated output DC voltage compared with the conventional UPS system. Performance of the system carried out through theoretical and experimental means.

• 한국산학기술학회논문지
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• 제7권6호
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• pp.1072-1077
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• 2006

본 논문은 AC 라인 리액터와 2개의 4레그 PWM 전압형 컨버터를 사용하여 병렬 및 직렬 능동필터 기능을 가지는 새로운 3상 Line-Interactive UPS 시스템을 제안하고 전압제어 방식을 설명한다. 제안하는 UPS 시스템의 병렬 및 직렬 PWM 전압형 컨버터에서 전압제어의 목적은 정상상태 및 과도상태에서 만족스러운 동작 특성을 보장하는 것이다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
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• pp.75-78
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• 2002

Since power failures in high-speed communication network, especially in HFC(Hybrid Fiber Coaxial cable) network are critical, microcontroller-based UPS(Uninterrupted Power Supply) are commonly used in the network. Hardware and software of UPS management system is designed and implemented to monitor and control UPS status to supply electric power to ONU and TBA in the HFC network. The result of laboratory tests and field tess of this system shows the scan rate to be 1 to 10 minutes to sufficiently monitor the status of UPS in the network.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.195-204
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• 2015

In this paper, the development of a cost-effective active power filter/uninterruptible power supply (APF/UPS) system with seamless mode transfer is described. The proposed scheme employs a pulse-width-modulation (PWM) voltage-source inverter and has two operational modes. First, when the source voltage is normal, the system operates as an APF, which compensates for the harmonics and power factor while boosting the DC-link voltage to be ready for the disturbance, without an additional DC charging circuit. A simple algorithm to detect the load current harmonics is also proposed. Second, when the source voltage is out of the normal range (owing to sag, swell, or outage), it operates a UPS, which controls the output voltage constantly by discharging the DC-link capacitor. Furthermore, a seamless transfer method for the single-phase inverter between the APF mode and the UPS mode is also proposed, in which an IGBT switch with diodes is used as a static bypass switch. Dissimilar to a conventional SCR switch, the IGBT switch can implement a seamless mode transfer. During the UPS operation, when the source voltage returns to the normal range, the system operates as an APF. The proposed system has good transient and steady-state response characteristics. The APF, charging circuit, and UPS systems are implemented in one inverter system. Finally, the validity of the proposed scheme is investigated with simulated and experimental results for a prototype APF/UPS system rated at 3 kVA.

• 융합신호처리학회논문지
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• 제19권3호
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• pp.97-103
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• 2018

본 논문에서는 비정상적인 과도상태에서의 개선된 해상 전투체계 UPS(Uninterruptable Power Supply) 시스템을 다룬다. 기존에는 일시적인 과전압 및 과전류에 대응하기 위하여 서미스터와 바리스터 소자를 사용하고 있지만 시스템 운용 중에 발생하는 비정상 과도전압에는 취약하므로 UPS가 비가용 상태로 되는 경우가 빈번히 발생하였다. 이를 극복하고 UPS 시스템을 보호하기 위하여 본 논문에서는 초기 입력전원 및 운용 중에 발생되는 비정상 과도전압을 감지한 입력 전원 차단회로, 전원제어 시퀀스 개선, 그리고 인버터 및 CPU 오동작 방지 방법 등을 제안한다. 제안된 방법으로 UPS 구현된 시스템은 Programmable AC/DC 발생기를 이용하여 입력전원 가변 시험을 통하여 시뮬레이션을 수행하였으며, 최종적으로 해상 전투체계의 다기능콘솔에 장착하여 현장시험을 통하여 신뢰성과 안정성을 검증하였다.

• 전기학회논문지
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• 제56권6호
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• pp.1064-1070
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• 2007

This paper presents a grid-interactive current controlled voltage source inverter (CCVSI) with uniterruptible power supply (UPS), which uses an inner current control loop (polarized ramp time (PRT)) and outer feedback control loops to improve grid power quality and UPS. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, a single stage CCVSI is used. The operation of this system could be divided into the power quality control (PQC) state mode and the UPS state mode. In PQC mode, the system operated to compensate the reactive power demand by nonlinear load or variation in load. In UPS mode. the system is controlled to provide a sinusoidal voltage at the rated value for the load when the gird fail. To verify the proposed system, a comprehensive evaluation with theoretical analysis, simulation and experimental results for 1KVA load capacity is presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.944-945
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• 2015

Many sensitive loads always rely on UPS systems to maintain continuous power during abnormal utility power conditions. As any disturbance occurs at the utility side, an off-line UPS system takes over the load within a quarter cycle to avoid a blackout. However, the starting of the inverter can root the momentous inrush current for the transformer installed before the load, due to its magnetic saturation. The consequences of this current can be a reduction of line voltage and tripping of protective devices of the UPS system. Furthermore, it can also damage the transformer and decrease its lifetime by increasing the mechanical stresses on its windings. To prevent the inrush current, and to avoid its disruptive effects, this paper proposes an off-line UPS system that eliminates the inrush current phenomenon while powering the transformer coupled loads, using a current regulated voltage source inverter (CRVSI) instead of a typical voltage source inverter (VSI). Simulations have been performed to validate the operation of proposed off-line UPS system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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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.