UPS Uninterruptible Power Supply Circuit Diagram

This article will teach you what UPS is and provide a UPS circuit diagram. It will also explain the difference between online and offline UPS. In addition, a practical circuit for a UPS is included in this article. Controlling sensitive devices such as computers, induction machines, medical equipment, and many other things is of utmost importance for an uninterruptible power supply. Many countries, including Pakistan, rely on UPS during times of energy shortage, using it to store energy in batteries when the main power supply is available. The same UPS converts the DC energy stored in batteries into an AC supply, providing power to AC operating equipment in homes during load-shedding timings. An uninterruptible power supply is mainly used for connecting devices that are highly affected by changes in the mentioned parameters and specified limits.

• Overvoltage
• under voltage
• voltage out
• voltage spikes
• frequency fluctuation of 1%
• distortion in the voltage waveform

What is an Uninterruptible Power Supply?

UPS uninterruptible power supply is a device used for protection against overvoltage and undervoltage. It provides a continuous power supply in case of an outage, and protection against voltage spikes, frequency fluctuations, and distortion in voltage waveform. In many cases, you may have heard of home devices getting burnt out due to overvoltage and undervoltage. UPS provides protection for these devices.

There are many places where a power outage may permanently damage data, such as banks or companies where computers need to remain on during working hours. In such cases, a UPS provides continuous power to the computers.

In industries, induction machines are mostly used. Induction machines are sensitive to frequency changes. Even a slight change in frequency can affect the output of induction motors. To avoid frequency changes reaching the input of the induction machine, a UPS is used.
Similarly, there are many devices that require a pure sine wave to operate properly. However, power

systems often use power converters that inject harmonics and distort the voltage waveform of the main power supply. In such cases, a UPS is used to provide a pure sine wave to the load.
However, many uninterruptible power supplies available in the market don’t have a pure sine wave output, which can negatively affect the performance of the loads and reduce the lifetime of the devices. Two main types of UPS are commonly used.

• Online uninterruptible power supply
• Offline uninterruptible power supply

Difference between online and offline UPS

Difference and their block diagrams are given below: Block diagrams shown below show the difference between online and offline uninterruptible power supply.

Block diagram of online uninterruptible power supply 

Offline uninterruptible power supply block diagram

The above block diagrams are self-explanatory. The following are the basic differences between them.

• Online UPS provides protection against overvoltage, undervoltage, main supply voltage waveform distortion, and frequency fluctuation.
• Offline UPS only provides protection against supply outages.

Practical circuit diagrams of offline UPS

 Power kit of offline UPS :

Control Kit of offline uninterruptible power supply :

Conclusion

In conclusion, an uninterruptible power supply (UPS) plays a vital role in protecting sensitive devices and providing continuous power in the event of an outage. It safeguards against overvoltage, undervoltage, voltage spikes, frequency fluctuations, and distortion in voltage waveform, ensuring the longevity and proper functioning of equipment. UPSs are essential in areas where energy shortages are prevalent, such as in countries like Pakistan during load shedding. The two main types of UPSs, online and offline, offer different levels of protection, with online UPSs providing comprehensive safeguarding against various power issues. Additionally, practical circuit diagrams for offline UPSs have been provided, illustrating the components needed for their operation. By utilizing UPS technology, individuals and industries can ensure the reliable operation of their devices and mitigate the risks associated with power interruptions.

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