A low cost resonant snubber inverter for uninterruptible power supply application

2005 ◽  
Author(s):  
Qinghong Yu ◽  
R.M. Nelms
Keyword(s):  
Power Supply ◽  
Low Cost ◽  
Uninterruptible Power Supply ◽  
Uninterruptible Power

scholarly journals DC UPS for Critical Loads

2015 ◽  
Vol 5 (2) ◽  
pp. 231
Author(s):  
Ganesh S ◽  
Chiranjit Ghosh T ◽  
Kokilasree R ◽  
Nandhakumar M ◽  
Md Haroon Alim T
Keyword(s):  
Power Supply ◽  
Low Cost ◽  
Uninterruptible Power Supply ◽  
Critical Data ◽  
Power Failure ◽  
Switching Losses ◽  
Dc Power ◽  
Full Power ◽  
Switched Mode Power Supply ◽  
Uninterruptible Power

<p>The usual way to avoid a computer shutdown during a mains failure is to connect an  uninterruptible power supply system (UPS), which can be suitably modified and fitted inside the computer cabinet by the use of proposed methodology known as a dc UPS.  Conventional desk top UPS systems store electricity in form of chemical energy in batteries and when ever mains fail the batteries provide DC power which is then converter to ac by inverter and then fed to the computer in order to save critical data.  Thus power from mains or from UPS is fed to switched mode power supply unit which converts it to dc to  supply the computer motherboard and accessories.  Leaving the case of the computer powered by mains, duing power failure the dc power is unnecessarily converted to ac and then to dc again in SMPS hence high switching losses and heat is produced there by making the entire system very lowe efficient.  In this work it is proposed to directly feed the dc power from the battery to the computer SMPS system by building a UPS arrangement within the computer system.  This not noly saves space, it is highly efficient compared to the conventional ups system, easy to carry, low cost and reliable since there is no change over operation is required/.  A complete design of an ac to dc power supply with an internal dc UPS is presented in this paper. . A prototype has been fully developed and tested as a PC power supply. Thus the result is achieved at full power about 6-8 minutes.</p>

A Single-Stage DC Uninterruptible Power Supply

2015 ◽  
Vol 764-765 ◽  
pp. 466-470
Author(s):  
Maoh Chin Jiang ◽  
Bing Jyun Shih
Keyword(s):  
Power Factor ◽  
Power Supply ◽  
Output Voltage ◽  
High Efficiency ◽  
Low Cost ◽  
Single Stage ◽  
Normal Operation ◽  
Uninterruptible Power Supply ◽  
Sinusoidal Input ◽  
Uninterruptible Power

A single-stage DC uninterruptible power supply (UPS) is proposed in this paper. Basically, the proposed converter is an integration result of a power factor correction circuit with a dc-to-dc converter to achieve simple hardware circuit, high efficiency, and low cost for extra UPS function. Under normal operation, a novel two-switch SEPIC converter operates as an ac to dc converter with sinusoidal input current, unity power factor, and low ripple dc output voltage, and as a battery charger if a battery is added. Since both the input boost supply and the output supply can be controlled independently, a fast transient response can be maintained at both the input for active current wave shaping and at the output for good output regulation. When the ac source is in an outage condition, the proposed converter functions as a dc-to-dc buck-boost converter; therefore, the desired dc output voltage can be provided. Finally, some experimental results are presented for verification.

scholarly journals Uninterruptible Power Supply Improves Precision and External Validity of Telomere Length Measurement via qPCR

2020 ◽  
Vol 1 ◽  
Author(s):  
Waylon J. Hastings ◽  
Dan T.A. Eisenberg ◽  
Idan Shalev
Keyword(s):  
Telomere Length ◽  
Power Supply ◽  
External Validity ◽  
High Performance ◽  
Epidemiological Studies ◽  
Storage Conditions ◽  
Amplification Efficiency ◽  
Uninterruptible Power Supply ◽  
Uninterruptible Power ◽  
The Impact

Abstract Technical challenges associated with telomere length (TL) measurements have prompted concerns regarding their utility as a biomarker of aging. Several factors influence TL assessment via qPCR, the most common measurement method in epidemiological studies, including storage conditions and DNA extraction method. Here, we tested the impact of power supply during the qPCR assay. Momentary fluctuations in power can affect the functioning of high-performance electronics, including real-time thermocyclers. We investigated if mitigating these fluctuations by using an uninterruptible power supply (UPS) influenced TL assessment via qPCR. Samples run with a UPS had significantly lower standard deviation (p < 0.001) and coefficient of variation (p < 0.001) across technical replicates than those run without a UPS. UPS usage also improved exponential amplification efficiency at the replicate, sample, and plate levels. Together these improvements translated to increased performance across metrics of external validity including correlation with age, within-person correlation across tissues, and correlation between parents and offspring.

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