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T is for Topology

T is for Topology

T is for Topology

Welcome to a regular feature on the Powertecnique blog. Every Monday we talk you through an A-Z of the terms you hear associated with critical power supplies. In this latest post we’ve reached the letter T. T is for Topology.


UPS (Uninterruptible Power Supplies) don’t all work in exactly the same way. It’s 1 that on the whole most UPS on the market today function in similar ways, but as with many things in life there is more than one way to keep the lights on when the power goes out. And there’s definitely more than one way to switch from mains power to your backup solution in less than 0.1 of a second.

What we are discussing here is UPS topologies. The topology is the design of the UPS and dictates how it provides its backup power and how the UPS switches from mains to backup power in the event of a power cut. There are many types of UPS topology available and two primary types are:

  • Line Interactive
  • Double Online Conversion

Line interactive UPS are amongst the simplest types of UPS you can find. In a line interactive UPS, the mains power is fed directly to the load and is also used to charge the battery. In the event of a power failure the UPS switches to the battery source to provide power through its inverter, however due to this need to switch between sources there is a typical transfer time of up to 10ms. As the load is fed by the mains supply in normal operation, most line interactive UPS only provide the basic power cleansing features, but due to their simplicity, they are one of the most cost effective solutions on the market.

Online double conversion UPS however offer a far higher level of protection. In a Double online conversion UPS the main incoming AC supply is  converted to a DC waveform to charge the battery and then converted back into a pure AC sine wave which is VFI (Voltage and Frequency Independent) of the incoming supply. This double conversion of the voltage is what gives this particular topology its name. It also means that the UPS is able to protect against voltage spikes and sags since it’s cleaning the supply in this manner. In addition to this, as the load is supported by the inverter during normal operation, in the unfortunate event of a mains power failure the UPS seamlessly switches to the battery backup to provide power to your critical load.

Online double conversion UPS generally manage battery life better too so can keep batteries lasting longer than line interactive UPS. Most UPS offered by Powertecnique are online double conversion due to the increased benefits that they bring.

Hopefully this has given you a bit more of an idea as to the different types of UPS topology. If there’s a topic you’d like covered in our A-Z why not get in touch via twitter. Our handle is @powertecnique.


Author: Owen McIntyre

20/01/2014 16:42:00
Listed in : A-Z of Critical Power  

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