The document discusses uninterruptible power supplies (UPS). It begins with an introduction and overview of UPS systems. It then discusses the need for UPS systems to provide backup power when main power fails and protect against power issues like surges, sags, noise and instability. The document outlines the history of UPS systems and describes the main UPS topologies - standby, line interactive, and online/double conversion. It also covers the typical architecture of UPS systems as either distributed or centralized. The document concludes that UPS systems help keep businesses running by protecting critical systems and data from power issues.

1. Joseph Brian D’Souza
4NM10EC039
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2.  Introduction
 Criteria influencing the need for UPS
 Power quality issues
 History
 UPS topologies
 Architecture of the system
 Conclusion
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3.  An uninterruptible power supply, also uninterruptible
power source, UPS or battery/flywheel backup is a
device that provides emergency power to a load when
the input power source fails
 The on-battery runtime of most uninterruptible power
sources is relatively short 5-15 minutes being typical
for smaller units but sufficient to allow time to bring
an auxiliary power source on line, or to properly shut
down the protected equipment
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4.  Applications where corruption of data of interruption
of power supply even for a fraction of a second cannot
be tolerated, an UPS is needed.
 A surge, dip, break, fluctuation, or other
contamination can in some situations prove to be
absolutely divesting
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5.  Surge
 Sag
 Noise
 Frequency instability
 Harmonic distortion
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8.  The first uninterruptable power supply equipments
were of rotary design, and introduced during 1950s
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9.  Around 1960’s invention of thyristor and diode.
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 The storage form of current is DC.
 When the electricity goes down the inverter converts
the stored DC into AC.

11.  When electricity comes back on the battery charges.
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12. There are basically three types of ups topologies
 Stand-by / offline
 Line interactive
 Double conversion/ online
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 Control unit, monitors the utility voltage and
frequency are within the specified limits.
 if the mains power goes of the specified limit, the
system control turns off the fast acting static switch
and turns on the inverter.

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 Normal mode - The load is supplied with utility AC-
input supply, generally via a filter / conditioner which
eliminates certain disturbances and can also provide
voltage regulation.
 Stored-energy mode - When the AC-input supply
voltage goes outside the specified tolerances or fails,
the battery and the inverter ensure continuity in the
supply of power to the load

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Advantages:
 Simple design.
 Low cost.
 small size.
Disadvantages:
 Long switching time.
 No regulation of the
output voltage.
 No regulation of the
output frequency.

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 The line-interactive UPS is similar in operation to a
standby UPS, but with the addition of a multi-tap
variable-voltage autotransformer.
 This type of UPS is able to tolerate continuous under
voltage brownouts and overvoltage surges without
consuming the limited reserve battery power.
 It instead compensates by automatically selecting
different power taps on the autotransformer.

18.  It is common for the autotransformer to cover a range
only from about 90 V to 140 V for 120 V power, and
then switch to battery if the voltage goes much higher
or lower than that range.
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 Normal mode - The inverter is operational to provide
output voltage conditioning and battery charging.
 Stored-energy mode - When the AC-input supply
voltage goes outside UPS preset tolerances or fails, the
inverter and battery maintain continuity of power to
load
 By-pass mode -In the event of a UPS internal
malfunction, the load may be transferred to the bypass
input via the maintenance bypass.

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Advantages :
 The cost may be lower
than a double-conversion
UPS of equal power
rating.
Disadvantages:
 Poor efficiency when
operating on non linear
loads.
 No real isolation of the
load from the upstream
distribution system.

22.  The most common type of large UPS today is the
Double Conversion UPS.
 An inverter that supplies power with a consistently
high level of quality.
 A static switch (static bypass) capable of transferring
the load to bypass power without a break in the supply
of power.
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23.  Normal mode - The load is continuously supplied via
the rectifier/charger - inverter combination which
carries out a double conversion AC-DC-AC.
 Stored-energy mode - When the AC-input supply
voltage goes outside UPS preset tolerances or fails, the
inverter and battery continue to support load power.
 By-pass mode - the load can be transferred without a
break to the AC bypass via the static bypass under the
conditions of UPS internal malfunction.
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Advantages:
 Continuous protection of
load is provided from the
inverter, whether it
originates from the AC-
input supply or the
battery.
 Isolation of the load
from the upstream
distribution system, thus
eliminating transmission
of any upstream
fluctuations such as
spikes and over voltages
to the load.
Disadvantages:
 High price.
 Power loss.

26. Basically there are two types of architecture
 Distributed architecture
 Centralized architecture
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27.  UPS hardware and other power protection equipment
is mounted directly adjacent to load.
 Commonly used in network closets and medium-sized
data centers.
 Distributed backup strategies generally feature large
numbers of smaller UPSs located in many places.
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Advantages:
 Lower capital expenses
 Better power availability
 Easier deployment and
redeployment
Disadvantages:
 More complex
management
 Less efficient rack space
usage

30.  A centralized backup scheme relies on one or two large
UPSs rather than lots of smaller ones.
 Those UPSs are usually situated in a separate room
nearby.
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Advantages:
 Easier management
 Simpler redundancy
 Better use of rack space
 Longer battery life in
low-temperature
environments
Disadvantages:
 Higher capital expenses
 Lower energy efficiency

33.  Businesses today invest large sums of money in their
IT infrastructure, as well as the power required to keep
it functioning. They count on this investment to keep
them productive and competitive. Leaving that
infrastructure defenseless against electrical dips,
spikes and interruptions.
 Various UPS types are appropriate for different uses
and no single UPS type is ideal for all applications. A
well-built power protection solution, featuring high-
quality, highly efficient UPS hardware, can help keep
business applications available, power costs
manageable and data safe.
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34. [1] “Uninterruptible Power Supplies” by John R Platts, John
St. Aubyn
[2] “Uninterrupted power supply”
(http://en.wikipedia.org/wiki/Uninterruptible_power_sup
ply)
[3] “Uninterrupted power supply”-
(ups.legrand.com/wp-
content/uploads/2011/07/Guida_UPS_EN.pdf)
[4] “Different types of ups system”
(www.apcmedia.com/salestools/SADE-5TNM3Y_R7_EN.pdf)
[5] “UPS topologies and standards”
(www.gruber.com/media/forms/MGE%20UPS%20Topologi
es.pdf)
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35. Thank you!
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