What Is The Difference Between UPS and Inverter

It is not hidden that we, in today’s era, heavily rely on gadgets and appliances that run on electricity. The next to unimaginable situation for electronic devices to run smoothly as expected is without a power supply. Indeed, even the smallest of fluctuations in it bring about extreme damage to the appliances. Here’s where the power backup supply devices- a UPS or an inverter- comes into play. These 2 power backup devices provide a constant, ideal, and never-ending flow of power supply in case of a power cut or blackout.

However, people often tend to confuse between the two and what should they buy- inverter or UPS. In this article, we will be explaining everything you need to know that will clear all your doubts. But the most ideal approach to comprehend the difference between a UPS and an Inverter is by first understanding what exactly are these devices and how do they work. Let’s have a look at that.

What is a UPS?

UPS is the abbreviation for Uninterruptable Power Supply. A UPS is an electrical device that supplies power backup in case of a power cut/failure/drop and facilitates the smooth working of your gadgets without damaging them. A basic UPS system includes batteries, a charging unit, an inverter, and a transfer switch. A UPS is utilized for devices like PC, servers, workstations performing critical operations, and the ones that can’t tolerate delays in power supply.

How Does A UPS Work?

Just as the name suggests, a UPS supplies power continuously without any interruption when there are power cuts or power grid disturbances. UPSs can be categorized into 3 types based upon their work:

1. Online UPS

Working of Online UPS
  • Consists of batteries, a rectifier, and an inverter in combination with the AC mains supply and load.
  • The power from AC mains is first fed to the rectifier, followed by the conversion of the power from AC to DC.
  • The DC power is then supplied to the inverter and further supplied to the load.
  • The DC power is also utilized for the charging of batteries present in the UPS.

2. Offline UPS

Working of Offline UPS
  • The AC power is directly supplied to the UPS circuit connected to the load.
  • The transfer switch position is changed by the UPS in case of a power failure.
  • This connects the path of battery backup and the load.

3. Line-Interactive UPS

  • This variant can be considered as an amalgamation of Online and Offline UPS.
  • Here, the inverter is a part of the output and works in reverse for the charging of batteries and turning on its power in case of input fails.

The working of a UPS demands 2 conditions:

  • Energy storage: The energy in a UPS is stored with the help of batteries and a charge controller. The UPS utilizes this stored energy in case of an electric supply interruption.
  • Instant response: An instant response is required for the continuity in the working of a UPS system when a blackout or power cut occurs.

What Is An Inverter?

An inverter is an electrical device that receives DC, converts it into AC, and supplies power in case of power cuts. Inverters are available in different loading and voltage capacities. An inverter is generally incapable of generating or storing power however, it can be connected to power resources to facilitate power supply. Inverters might work as a standalone device or as a power backup supply.

The components of an inverter include an oscillator, control circuit, transformer, drive circuit, and switching devices. An inverter operates inversely for converting AC into DC when the mains is ON helping charge the battery. Inverters utilize batteries of 100Ah-200Ah capacity which are capable of providing a power backup. 

How Does an Inverter Work?

Working of Basic Inverter

An inverter works by converting DC power stored in the batteries or rectifier output into AC for fulfilling the requirement of devices or appliances. The inverter utilizes certain sensors and relays for detecting the need for DC power. The AC power supply gets interrupted by disconnecting the inverter from its DC source. Inverters contain a rated power just like any other electrical device. Moreover, they are intended to operate in a certain range of voltage on both DC as well as AC sides.

An inverter is categorized into 2 types based upon their work:

1. Single Phase Inverter

  • Also known as half-bridge inverters.
  • As the name suggests, it converts the DC power supply into a single-phase AC power supply with the help of two switching devices.
  • Diodes and switching devices help in the smooth working of the circuit.
  • Two types: Half-bridge inverters and Full-bridge inverters.

2. Three Phase Inverter

  • Also known as a full-bridge inverter.
  • A three-phase AC voltage is obtained on the load side from the DC supply hence, the name.
  • These kinds of inverters require a total of 6 switching devices.
  • Three-phase inverters work in 2 ways: 120o mode of conduction and 180o mode of conduction.

Recommended: Best Inverters In India

UPS vs Inverter

After the brief introduction of UPSs and inverters mentioned above, we assume you must have got a basic idea regarding both of them. The following table of differences between a UPS and an inverter will help you acquire a better understanding of their differences.

FACTORSUPSINVERTER
FunctionInstant power backup supply without any interactionConversion of DC to AC power
Power InputAC and DC options – Around 240-279 VacOnly DC – Around 170-270 Vac
Response SpeedLess than 10 millisecondsAround 500 milliseconds
Output ConnectionsIncludes receptacles to directly connect appliancesAC terminals only
Backup TimeShort durationLong duration
Battery MaintenanceNot requiredRequired
ApplicationDomestic and industrial purposeGeneric electric applications

In this war of UPS vs Inverter, we believe you must have got an overall idea about the differences between the two. However, to discuss in detail, when we consider the same power rate, a UPS due to its additional components and functions, is generally more expensive than an inverter. UPS supplies power backup for only about 15-20 mins because it is mainly intended to provide an immediate backup for you to save data and programs.

Nevertheless, the purpose of an inverter is to provide power back to the entire house and its appliances like lights, fans, etc. When it comes to maintenance, an inverter requires proper and continuous maintenance since it utilizes a tubular or flat plate battery and demands to be fed with distilled water toppings at regular time intervals. But a UPS comes with an SMF (Sealed Maintenance Free) battery hence, no maintenance is necessary.

A change over time is the time taken by the battery backup system to provide a power supply after the power cut. The changeover time in the case of UPS is seen to be 10 to 15 milliseconds whereas an inverter’s change over time is usually 500microseconds. In spite of the fact that delays are nominal and minimal in both of the devices, inverters are considered to be better for sensitive power operating gadgets.

The circuitry of a UPS way more sophisticated than that of an inverter’s circuitry. This can be attributed to the high-quality output expectations of a UPS with less delay in the circuit. A UPS proves to be efficient in protecting against voltage drops/spikes, harmonic distortions, and main frequency instability while an inverter has no role in providing protection against any sort of line abnormalities.

How To Decide What You Need?

Both the UPS and inverter supply power backup in absence of power supply to the electrical system. However, both of them have merits and demerits. We believe you might have got the answer to “Should I buy UPS or inverter?” looking at the definitions, working, and differences between a UPS and an inverter.

By now you must have understood that there are factors like function & application, energy storage, backup time, changeover time, power input, battery maintenance, circuitry sophistication, expenses, power prerequisites & protection, etc that are needed to be considered at the time of buying the product.

For businesses and organizations having high application requirements in terms of power system reliability, there’s no doubt in choosing a UPS over an Inverter due to its minimal delay and assurance of data security. But when it comes to general domestic applications it’s prudent to use an inverter for this purpose as the working of these gadgets (fans, lights, bulbs, TV, etc) won’t be hampered by longer switching time. Nevertheless, in the case of critical devices like Computers, a UPS would be advised to be bought.

In the end, it all comes down to your power requirements and we hope understood the difference between a UPS and an inverter and figured out what suits you the best for and your needs.

Samarth is a Mechanical engineer from IIT Bombay with deep understanding of machines and the overall market. Samarth has been building machine from over 8 years so all his reviews on November Culture are first hand expert review. He co founded November Culture along with few other industry experts to provide reviews of daily products.