This document summarizes different types of uninterruptible power supplies (UPS). It describes UPS as a standby electrical power source that provides instantaneous backup power in the event of an outage or fluctuation to protect sensitive electronic devices. It discusses three main types of UPS - offline, line interactive, and online - and goes into detail about the components, operation, and benefits of an online UPS system, including the rectifier, battery charger, DC system, inverter, output, and static bypass.

1. Seminar by:
S.Murali krishnan
5050910061-B Tech EEE,
SRM University,
Chennai

2. What is UPS?
UPS – Uninterruptible Power Supply is a
standby electrical Power source connected
between the Power Utility and the load.

3. • Modern Electronic gadgets and computer
systems are highly sensitive to the power
fluctuations
• Disruption of power may lead to Data loss/
corruption/ malfunction etc.
• Standby Power Sources - Generators
• Starting the generator takes a few minutes.
UPS is mainly used as a Power Backup for
the above few minutes

4. • UPS maintains power instantaneously by
switching to battery in the event of a power failure
or a dip (brown out)
• Used to condition the power supply by reducing
spikes and harmonics.
• Designed to correct a variety of power problems -
- Sags – Transient Under voltage
- Surge – Short duration high voltage
- Brownouts – Low voltage for long time
- Spikes – Brief but high energy bursts
- Line noise, frequency variation, switching
transient and Harmonic distortion

5. Three types of UPS
1. Offline UPS
2. Line interactive UPS
3. Online UPS
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6. 1. Offline UPS
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7. 2. Line Interactive UPS
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8. 3. Online UPS
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9. Online UPS
Main components of UPS:
- Rectifier / Battery Charger
- Battery
- Inverter
Main features for a Good UPS:
- Shortest changeover time < 4mS
- Sufficient battery backup time
- Quality output supply
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10. Online UPS
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11. Online UPS - Operation
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12. Online UPS
Elements of UPS:
- Input
- Rectifier / Battery Charger
- DC System
- Inverter
- Output
- Static Bypass
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13. Online UPS
Elements of UPS:
- Input
- Rectifier / Battery Charger
- DC System
- Inverter
- Output
- Static Bypass
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14. Online UPS - Input
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15. Online UPS - Input
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16. Online UPS - Input
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17. Online UPS - Input
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18. Online UPS
Elements of UPS:
- Input
- Rectifier / Battery Charger
- DC System
- Inverter
- Output
- Static Bypass
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19. Online UPS -Rectifier
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20. Online UPS -Rectifier
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21. Online UPS -Rectifier
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22. Online UPS -Rectifier
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23. Online UPS -Rectifier
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24. Online UPS -Rectifier
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25. Online UPS -Rectifier
Switching speeds and power ratings – SCR Vs IGBT
108
Thyristor
Power (VA)
IGCT
106
Thyristor IGCT IGBT
104
102 MOSFET
101 102 103 104
IGBT MOSFET Switching Frequency (Hz)
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26. Online UPS
Elements of UPS:
- Input
- Rectifier / Battery Charger
- DC System
- Inverter
- Output
- Static Bypass
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27. Online UPS – DC System
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28. Online UPS – DC System
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29. Online UPS
Elements of UPS:
- Input
- Rectifier / Battery Charger
- DC System
- Inverter
- Output
- Static Bypass
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30. Online UPS – Inverter
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31. Online UPS – Inverter
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32. Online UPS – Inverter
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33. Online UPS – Inverter
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34. Online UPS – Inverter
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35. Online UPS
Elements of UPS:
- Input
- Rectifier / Battery Charger
- DC System
- Inverter
- Output
- Static Bypass
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36. Online UPS – Output
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37. Online UPS – Output
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38. Online UPS
Elements of UPS:
- Input
- Rectifier / Battery Charger
- DC System
- Inverter
- Output
- Static Bypass
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39. Online UPS – Static Bypass
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40. Online UPS – Static Bypass
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41. Online UPS – Other points
• Design Factors
• Typical Circuit
• Typical PCB
• Faults
• Do’s
• Don’ts
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42. Online UPS – Design Factors
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43. Online UPS – Typical Circuit
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44. Online UPS – Typical PCB
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45. Online UPS – Faults
Overload Trip
Battery Low trip
Output OV/ UV
Over Temperature
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46. Online UPS – Do’s
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47. Online UPS – Don’ts
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