Uninterruptible power supply systems provide protection

Gurrero, J.M.; Vicuña, Luis García de; Uceda, J.

doi:10.1109/mie.2007.357184

Cited by 167 publications

(66 citation statements)

References 37 publications

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“…The capacitance of the output capacitor and the maximum R DSON of S iso MOSFETs have been calculated with equation (5). The inductor value is the highest that can be obtained with an E30 core taking into account R p .…”

Section: Resultsmentioning

confidence: 99%

“…Nevertheless, it should be taken into account that the lower the R DSON of S iso , the higher the value of the output capacitance [see equation (5)]. Hence, this should be considered when designing the system for a specific UPS.…”

Section: Appendix Amentioning

confidence: 99%

“…These sheets can be used for comparing several UPSs and determining which is the most suitable for a certain application [3][4][5][6]. In the third section of this classification sheet, the dynamic of the output voltage under several conditions is analyzed and compared with one of the three possible behaviors considered in the regulations (see Fig.…”

Section: Introductionmentioning

confidence: 99%

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Elimination of the Transfer-Time Effects in Line-Interactive and Passive Standby UPSs by Means of a Small-Size Inverter

Arias

Hernando

Lamar

et al. 2012

IEEE Trans. Power Electron.

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Abstract--The main drawback of line-interactive and passive standby uninterruptible power supplies (UPS) is the transfer time when changing from normalmode of operation to battery-mode of operation. During this time, the critical loads protected by the UPS are under the influence of the grid disturbance which forced the mode change. On the other hand, equipment protected by a double conversion UPS is never affected by any disturbance in the mains. Nevertheless, the efficiency of this topology is lower and its size and cost are considerably higher. Hence, the elimination of the transfer process between modes in line-interactive and passive standby UPSs would make them more competitive than double conversion ones in many situations. In this paper, a method for eliminating the transfer time is proposed. It is based on a half-bridge inverter with a hysteretic controller whose output voltage is only applied to the load during the transfer time. Considering the random nature of the grid failures and the short duration of the transfer time, the design and selection of the components is nothing but standard. This also leads to a non-standard hysteretic controller that needs to be fully analyzed. Experimental results are provided for a 750-W lineinteractive UPS whose transfer time of 4 ms was eliminated by the proposed system.

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Section: Resultsmentioning

confidence: 99%

Section: Appendix Amentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Elimination of the Transfer-Time Effects in Line-Interactive and Passive Standby UPSs by Means of a Small-Size Inverter

Arias

Hernando

Lamar

et al. 2012

IEEE Trans. Power Electron.

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“…There are three common types of UPSes including the stand by UPS, line interactive UPS and double conversion UPS, each having their own inefficiencies [13]. The stand by UPS either solely uses the power grid or the battery to supply the load.…”

Section: Effects Of Phase Imbalance On Upsmentioning

confidence: 99%

Effects of phase imbalance on data center energy management

Gupta

Banerjee

Abbasi

et al. 2013

20th Annual International Conference on High Performance Computing

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Abstract-Phase imbalance has been considered as a source of inefficiency in the data center that causes energy loss due to line impedance and increases reactive power. Strategies assume high loss due to phase imbalance and propose sophisticated energy management algorithms including phase balance aware workload scheduling algorithm and dynamic power distribution unit assignment to servers. However, such attempts do not utilize an objective measure of the inefficiencies due to phase imbalance to evaluate the significance of their contributions. Excessive imbalance in a three phase load has various undesirable effects. This paper, first objectively characterizes the inefficiencies due to phase imbalance and then provides numerical measures of the losses in realistic data center deployments. Phase imbalanced load in a delta configuration results in reduced power factor, which is undesirable for several reasons. Also, an imbalanced load (both in delta or star configuration), results in higher line currents, leading to higher line loss. However, this increase in loss is a fraction of a percentage of the energy consumed. The paper also discusses effects of work load scheduling on phase imbalance, and how to minimize the same.

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“…This scenario, together with the huge increase on the installed PV power in many countries, makes the installation of ESS a more and more interesting solution for improving gridintegration of PV power plants [15,16]. Different ESS classifications can be established nowadays [17,18], most of them normally dividing ES technologies between those storing energy in an electromagnetic way (direct storage) and those storing energy in a mechanical or chemical way (indirect storage). In the direct storage group, technologies such as ultracapacitors (UC) or superconducting magnetic energy storage (SMES) can be highlighted, while in the other group, technologies such as pumped hydro (PHES), compressed air (CAES) or flywheels can be pointed out as mechanical systems, and fuel cells (FC), Thermo electric energy storage (TEES) or batteries (BESS) as chemical ones.…”

Section: Energy Storage Systemsmentioning

confidence: 99%

Influence of the State-of-Charge Control on the Size of the Energy Storage Systems

Beltrán¹,

Vidal²,

Gil³

et al. 2013

REPQJ

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-The usefulness of introducing energy storage (ES) systems (ESS) into PV power plants to make the production less stochastic and even predictable is a fact. Its economic viability is not so clear though, what makes essential the use of an optimally sized ESS. This paper analyses how much the energy ratings required by these ESS can be reduced by varying the values of a control parameter: the ESS reference state-ofcharge (SOC) recovery time (τ SOC ). This control parameter is introduced to force the plant to recover a given SOC within a certain period of time, thus reducing the SOC variability and allowing the use of smaller ESS. To do the analysis, a generic PV plant with ES is first introduced its main control equations. Then, two energy management strategies are defined to operate it. The analysis shows the τ SOC impact on the plant performance and also on the change in the ESS ratings obtained by varying the τ SOC value for each of the strategies is presented. The results obtained in this paper are based on one year long simulations which used actual irradiance data sampled every two minutes.

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Uninterruptible power supply systems provide protection

Cited by 167 publications

References 37 publications

Elimination of the Transfer-Time Effects in Line-Interactive and Passive Standby UPSs by Means of a Small-Size Inverter

Elimination of the Transfer-Time Effects in Line-Interactive and Passive Standby UPSs by Means of a Small-Size Inverter

Effects of phase imbalance on data center energy management

Influence of the State-of-Charge Control on the Size of the Energy Storage Systems

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