What is an UPS or Uninterruptible Power Supply?
An uninterruptible power supply is a device that allows a computer or machine to keep running for the short period of time when the incoming power is interrupted (raw power not available).
To keep machine on UPS takes energy from the Rechargeable Sealed Maintenance Free (SMF) – VRLA batteries of Amaron QUANTA & EXIDE make.
Nowadays for small rating UPS from 1kva to 40kva Li-ion battery pack are also used and from rating 500kva to above Rotary UPS transforms kinetic energy to electric energy. But these Rotary UPS have very big instalments cost but have the low maintenance cost. Ex. Google Gurugram have replaced their traditional IGBT Based UPS to the Rotary UPS apart from the fact that they are very costlier than the Dual-Conversion Based Transformer UPS.
For the sake of the simplicity, in the absence of input power an UPS takes DC power from the batteries and then converts it to the AC to make your machine run.
Now we will learn the working and block diagram of an Online UPS, lets jump right into it.
Block Diagram of Online UPS
The block diagram of an Online UPS consists of the following 5 major components:
1. Input Power or Raw Power (230V Single Phase or 430V Three Phase Supply)
2. Battery Bank (Gives Power to your load when Input Power is not available)
3. Rectifier + Charger Circuit (Converts AC to DC for Charging Battery & Supply to Inverter Circuit)
4. Static Switch (Normally ON & Normally OFF Switch – Final Onn/Off Switch to Load)
5. Load (Computer, Machines, Lights etc.)
Working of Online UPS : How does an Online UPS Works?
There can be situation for an Industrial Online UPS's working. An Online UPS performs different operations in different situations which are discussed below:
CONDITION 1: WHEN MAINS SUPPLY IS ON
The highlighted portion shows the operation of an Online UPS when the input mains supply is available (230V 50Hz AC or 430V 50Hz AC)
1. The AC input supply 230V 50Hz (Single Phase) or 430V 50Hz (Three Phase) is the main supply called Raw Power, directly from the transformer to the UPS (Rectifier Circuit).
2. The rectifier circuit will change the applied ac input signal into a dc signal and the dc output of the rectifier is simultaneously fed to the inverter as well as the battery in order to charge the latter.
3. Then the Inverter converts the DC signal coming from the rectifier to the AC Signal.
4. The same AC signal is provided to the NORMALLY ON Static Switch, through which the AC Power delivered to the load.
In this mode of operation, power to load is supplied along with simultaneously charging of the battery.
CONDITION 2: WHEN MAINS SUPPLY IS OFF
In the absence of an Input AC Signal, the rectifier will be in temporarily disconnected state and the highlighted circuit will work.
1. Battery will provide power – the DC Current to the inverter circuit (without any delay – say 0 transfer time).
2. The inverter circuit then converts this DC to AC Signal and fed it to the NORMALLY ON Static Switch.
3. Then the power will be forwarded to the load through the NORMALLY ON Static Switch.
In this way the stored power of battery is used to provide backup to your machine in case of power cuts.
CONDITION 3: WHEN UPS FAILS
When an UPS Fails or there will be problem arise of malfunctioning of the inverter or the rectifier circuit. Means by any failure UPS is unable to provide continuous power to the load. Then to prevent the tripping of the load, NORMALLY OFF Static Switch comes into the role which is clear from the picture and described below:
1. Since the rectifier or inverter circuit is not working properly then NORMALLY OFF Static will comes in ON STATE and opens an alternative path for the current to go from input of the UPS (Raw Power) to the Load (computer, machines, etc.) In this way you do not have to face the Power Failure.
2. In between this UPS send signal to the Control Unit and starts the Failure Alarm with Beeping Sound so that engineer would come and resolve the problem.
Yes, what would happen if Input Power Cuts Off?
This will be the worst case now you have to face business loss due to the unavailability of Electric Power.
To prevent this most companies used UPS in Parallel Configuration so that if one UPS Fails then other would provide the Power to the Load.
We will learn the UPS in Parallel Configuration in next module.
Thanks,
Onix Power
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WHAT ChatGPT SAYS ABOUT THE ONLINE UPS?
An Online UPS (Uninterruptible Power Supply) is a type of UPS that provides continuous power supply to connected devices or equipment without interruption, even during power outages or fluctuations. In an online UPS, the incoming AC power is first converted to DC power by a rectifier, then the DC power is converted back to AC power by an inverter before being supplied to the connected devices or equipment. The inverter constantly regulates the output voltage and frequency, ensuring that the connected devices receive stable and clean power.
One of the main advantages of an online UPS is that it provides high-quality power, which makes it ideal for sensitive equipment that requires a stable and reliable power supply, such as servers, data centers, medical equipment, and telecommunications systems. Online UPS also provides protection against various power problems such as voltage surges, voltage sags, harmonic distortion, frequency variations, and complete power outages.
However, one of the disadvantages of an online UPS is that it is less energy-efficient than other types of UPS, such as line-interactive or standby UPS. This is because the inverter is constantly running and consuming power, even when the connected devices are not using any power.
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