A little bit of theory on the UPS

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A little bit of theory on the UPS
When happens a black out
the darkness!
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A little bit of theory on the UPS

• When happen a black out
• - of persons,
• - of sensitive data,
• of important information,
• careful events

Safety
is at risk!
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A little bit of theory on the UPS
Spikes, impulse or oscillatory transients, sags
or undervoltage or overvoltage, harmonics and
power failure could be dangerous for the load!
from the mains
the desiderata of the load!...
is the output of the UPS!!!
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A little bit of theory on the UPS
An incandescent lamp will dim due to the lower
heat emission from the filament. Commutated
electric motors vary their speed in response to
voltage changes, so they will slow down. AC
induction motors and three-phase motors will draw
more current to compensate for the decreased
voltage, which may lead to overheating and damage
of the insulation on the motor's field winding A
linear power supply (consisting of a transformer
and diodes) will produce a lower voltage for
electronic circuits, resulting in slower
oscillation and frequency rates. In a CRT
television, this can be seen as the screen image
shrinking in size and becoming dim and fuzzy. A
switching power supply may be minimally affected
if it was designed to compensate for
over/under-voltage. However this is highly
design-dependent, and it can malfunction and
destroy itself if operated outside its normal
voltage range.Computer systems and other
electronic storage devices are susceptible to
data loss or hardware damage that can be caused
by the sudden loss of power.
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A little bit of theory on the UPS
To solve the problem
Uninterruptable Static Power Supply
Rotary UPS
For big power only and to protect only against
brownout.
Gen Set
For middle/big power and long autonomy. It
doesnt protect brownouts.
For any power and type of load, autonomy till 1
or 2 hours (even longer but with high cost of
batteries)
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A little bit of theory on the UPS
OFF LINE - STAND BY LINE UPS
LINE INTERACTIVE UPS
ON LINE DOUBLE CONVERSION UPS
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A little bit of theory on the UPS
OFF LINE - STAND BY LINE UPS
Utility power is feeding the load ? Disconnect
switch (solid state or electro-mechanical) ?
Charger is on, keeping the battery under charge ?
Inverter is off ? No voltage or frequency
regulation ? from 1.5ms to 5 msec transfer time
(with break on the output)

• brief power outage as the device switches between
  the AC mains and the inverter
• no mains voltage regulation and low filtering
• the output power will be dirty

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A little bit of theory on the UPS
LINE INTERACTIVE UPS
? Utility power is feeding the load, through a
buck-boost transformer or inductor that provides
some amount of over/under voltage regulation
?The main inverter provides the compensating
voltage/current to help stabilize the output
power. ? Charger is on, keeping the battery
under charge ? Voltage regulation ? no break on
the output

• frequent use of the battery -gt short battery life
• lack of effective power line isolation, little
  filtering

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A little bit of theory on the UPS
ON LINE DOUBLE CONVERSION
? Double Conversion (AC to DC, DC to AC) ? IGBT
PWM Inverters ? 6 or 12 Pulse SCR or IGBT
Rectifier ? Continuous Rated Static Bypass ?
Maintenance Bypass

• load is fed continuously from the inverter
• the load never sees a power drop if the AC mains
  fail because the load is continually powered by
  the UPS.

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A little bit of theory on the UPS
Building Blocks of Typical UPS
RECTIFIER
It converts input 'AC' power to 'DC'. This DC
power is fed to the Inverter and also used to
charge the Battery.
ON LINE DOUBLE CONVERSION UPS
It converts 'DC' power received from Rectifier
and/or Battery to the conditioned stable AC
power. The Inverter design defines the quality of
output power.
INVERTER
It is the alternate source of power. It gets
charged from Rectifier / Charger, when incoming
supply is available. And it acts as a backup
source (of 'DC' power) to Inverter, when the
supply is not available.
BATTERY
ST.SWITCH
It transfers load intravenously from UPS to by
pass vice versa
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A little bit of theory on the UPS
ON LINE DOUBLE CONVERSION UPS
Importance of Rectifier Design in UPS In UPS
system rectifier design plays vital role since
-It decides input supply window-It maintains
input Power Factor presented to the supply -It
controls Harmonics injected to the supply -It
decides Generator size -It maintains manages
Batteries in top conditions
RECTIFIER
Types of Rectifiers

• Single Phase Rectifier
• Three Phase Rectifier
• 6 pulse
• 12 pulse
• PWM Rectifiers

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A little bit of theory on the UPS
ON LINE DOUBLE CONVERSION UPS
RECTIFIER
Three Phase Rectifiers
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A little bit of theory on the UPS
ON LINE DOUBLE CONVERSION UPS
Harmonics are unwanted frequency component
associated with Fundamental (60Hz for AC power
supply) The frequencies such as 120 Hz, 180 Hz,
300 Hz are called as Second, Third Fifth
Harmonics respectively. High percentage of
Harmonics will lead to - Supply transformers
getting hot and noisy - Frequent failure of
induction motors or they run very hot - Neutral
conductors getting hot due to excessive current -
Stand by generator operating at poor efficiency
(50-60) - Under utilisation of source
HARMONICS
RECTIFIER
Three Phase Rectifiers
It measures how effectively the electrical
power being used. Poor PF means - Under
utilization of electrical power - More losses,
less efficiency - Heating of cables, utility
transformer
POWER FACTOR
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A little bit of theory on the UPS
ON LINE DOUBLE CONVERSION UPS
RECTIFIER
Three Phase Rectifiers
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WITH PULSE RECTIFIER BRIDGE!
Atlas
SuperNova
Quasar
Vela
kVA

10
15
20
25
30
40
80
120
160
300
50
60
100
nominal power
WITH IGBT RECTFIER
Auriga
2010 MASSPRODUCTION
Mizar
Alcor
Alcor40