What are online ups?
Online UPS is a type of UPS that uses a combination of rectifier and inverter circuits to deliver continuous power to the load from the supply source without any interruption. By continuous power here we mean that power is supplied to the load from the source in case of availability and power outage as well without any transfer time.
Online ups system is sometimes also known as a double-conversion system. The reason behind calling it so is that, within an online UPS system, power conversion occurs twice as the circuit contains a rectifier and an inverter.
There is a transfer switch, but that will constantly be in the ON position. Thus, at every time, the power delivered to the load will be from the combination of the rectifier and inverter circuit. The main benefit of using Online UPS is that no switch is required between the main power line path and the battery backup path during a power outage.
How it works
Power to the critical load can be provided in three ways. Such as:
- Directly from ac mains to the critical load (including rectifier, inverter circuit, and primary static switch).
- from battery backup to critical load (including inverter circuit only).
- Lastly, from ac mains to critical load without including rectifier and inverter circuit via following the path, or through the secondary static switch.
It is to be noted here that the primary static switch is in a normally-on condition always but gets turned off only when the UPS system fails. And bypassing the secondary static switch which is kept off normally now gets on.
Working principles When supply mains is on
The supply will equip a single-phase or three-phase ac signal as input to the rectifier circuit. The rectifier circuit will change the applied ac input into a dc signal. The dc output of the rectifier is simultaneously provided to the inverter as well as the battery to charge the latter. Thus, the rectifier here functions as a charger as well as a rectification unit and thus is of high rating.
The dc signal fed to the inverter will transform the dc signal into ac. This ac signal is provided to the normally on-static switch through which the ac power is given to the load. Hence, in this mode of operation, power to the critical load is supplied along with simultaneous charging of the battery.
Working principles When supply mains is off
In the absence of an ac input signal, the rectifier will be in a temporarily detached state, in such a condition, the stored power within the battery is provided to the inverter. And from this point, the online ups inverter commences operating like the previously discussed condition as taking the dc input and converting it into output and providing it to the load via normally on the static switch.
However, the supply from the battery backup must not sum up any delay or interruption to the operation. The battery backup is utilized either till the time of restoration of the ac supply or until the battery power gets drained off, whichever condition occurs earlier.
Working principles When UPS fails
When the inverter circuit fails, it will not allow the load to draw the current from the supply input. However, for proper operation, the supply input must be delivered to the critical load. So, in this situation, through a bypass way, the load draws power from the source.
Basically, when the inverter circuit fails then the secondary static switch reaches to on-state from the normally-off state. And through this, the ac signal will reach the load with zero phase discontinuity in just one-fourth of the complete cycle period.
The moment the secondary static switch gets turned on, an alarm intimates the attendant reading the collapse of the UPS system and thus can be diagnosed and corrected.
Advantages of Online UPS
- Online UPS does not require switching between the two paths in case of power outages. Thus, the power provided to the load will not be interrupted.
- The significant advantage of using Online UPS is that the isolation between the load circuit and input circuit is accurate, which is useful to get distortionless signals.
- In Online UPS the inverter is always in ON mode. Thus the power delivered to the load will be functional at every instant of time, as there is zero transfer time.
Disadvantages of Online UPS
- The designing of Online UPS is quite complex, as it needs a large heat sink.
- The power excessiveness in the case of Online UPS is more because it is supplying power instantaneously to battery backup as well as the inverter circuit.
- The cost of designing online ups is much higher than that of Offline Ups.
Since 1998 Power Logic has been operating. By understanding the changing needs of markets we have decided to provide comprehensive solutions that allow you to protect your most valuable assets – your computers and data. We have continued to develop unique products with our commitment and professionalism to establish our channel nationwide.UPS & AVR are the first products we developed. We have various ranges of UPS with capacities ranging from 800 VA to 480 KVA. We have several types of UPS that deliver reliable power and with real-time power management software, we can control and auto shutdown multiple servers. Besides that, Power Logic also has a wide range of UPS for industry use as three-phase True online UPS and N+X Modular type UPS. Power Logic Malaysia Top 100 industries, leading in the heavy-duty and high-performance industry for green power solutions. Visit our official website for more information- https://kossups.com.my/.