Working of 5KVA or more UPS........

Thread Starter

RRITESH KAKKAR

Joined Jun 29, 2010
2,829
Hi,

I am interested to know about working of High KVA rating UPS working........
As UPS convert DC to AC .......
Like online and offline UPS.
 

Thread Starter

RRITESH KAKKAR

Joined Jun 29, 2010
2,829
Yes i have seen it and gone through it..........
i want to start with 30watt then move to high rating as this is my cool project...if you want to give any other project that is good i can try it also.
 

praondevou

Joined Jul 9, 2011
2,942
Yes i have seen it and gone through it..........
i want to start with 30watt then move to high rating as this is my cool project...if you want to give any other project that is good i can try it also.
Starting with 30W shouldn't be a problem. Going towards 5kVA later on will require that you change the whole power part and layout, i.e. it will be a different project.

Also, for 30W or 5kVA you will probably not use the same topology.
There are different topologies for every power range.

What will be the specs of your UPS?
Input voltage range
Output voltage
Output power
PFC at the input?
Battery backup time
3 phase / monophase input/output?
Protections? input/output overvoltage/overcurrent limits and UPS behaviour, inverter to mains synchronisation lock-in range and speed.

This is not a small project so you should figure out what you want to do before starting to mount any circuits.
You can go with what Wookie suggested or build one from scratch, which will take you months... at least. :)

You basically will need a rectifier/charger, inverter and static switch.


Btw, you want a cool project? Then why not build something that doesn't exist? There are already tons of UPS available on the market, in all power ranges....
 

Thread Starter

RRITESH KAKKAR

Joined Jun 29, 2010
2,829
Btw, you want a cool project? Then why not build something that doesn't exist? There are already tons of UPS available on the market, in all power ranges....
OK, first you tell then what to build...??
 

Georacer

Joined Nov 25, 2009
5,181
Don't get disappointed. I have a friend who frowns upon many of my projects, just because they don't have a practical use.
Just build what makes you happy, that's my opinion.
 

kubeek

Joined Sep 20, 2005
5,622
Find some 300-500w UPS, dead or alive, take it apart and salvage the components. Then look at the driver PCB, try understanding why is there each of the parts, and when you think you know it all start designing your circuit.
 

praondevou

Joined Jul 9, 2011
2,942
I'm not saying don't build the UPS nor it isn't a nice project, but you will spend TIME and MONEY on 5kVA.
Then, when being discussed on THIS forum you will get to a point where people won't be allowed to help you because, to save cost, your project will not necessarily be isolated from mains. Even if it was isolated it will still contain high /dangerous voltages in various parts of the system. If you think you have the experience to undertake such an endeavour you will need to get help elsewhere, otherwise I suggest you try something less time and cost intensive and less dangerous.


Also, what's is your location and part distributor access? There were some people here, who had a hard time finding parts
that were suggested to them, because they were either not available or much to expensive...

There are so many things one could build... I prefer projects that are useful to me or to others. Maybe you can think of
something you could use at home. It's hard to suggest something if we don't know what your interests are. You could suggest something you always wanted to build but have no idea where to start for example...
 

Thread Starter

RRITESH KAKKAR

Joined Jun 29, 2010
2,829
Also, what's is your location and part distributor access? There were some people here, who had a hard time finding parts
that were suggested to them, because they were either not available or much to expensive...
Don't worry about part, i will try it.


There are so many things one could build... I prefer projects that are useful to me or to others. Maybe you can think of
something you could use at home. It's hard to suggest something if we don't know what your interests are. You could suggest something you always wanted to build but have no idea where to start for example...
OK, my interest till ow is in Electronics and Dish setups..

and if we talk about UPS i will make some change like i will make it wireless monitor for viewing o/p response of freq., voltage, current and % of load...
and i am thinking of connecting it to computer like for viewing as monitor through internet, like that, etc........

your idea are also welcome.
 

Thread Starter

RRITESH KAKKAR

Joined Jun 29, 2010
2,829
Hi kubeek,
Most of people were saying it has not god regulation something like taht...and in my computer small UPS has many op-amps...
can you tell me about them?
thanks
 

kubeek

Joined Sep 20, 2005
5,622
Well, there is a huge difference between a square wave ups and other kinds.
Also, you were asking what is a good multivibrator for a square wave ups. This doesn´t mean that to build a complete UPS with all protections etc. you don´t need anything else than a 555.

Another thing is that the multivibrator depends on what topology of ups and what transformer you use. For your wattage a 555 can be enough, for higher wattages and different modulation schemes, other parts like tl494 might be better.
 

kubeek

Joined Sep 20, 2005
5,622
The datasheet suggests 2.2M and 1000 pF for 100Hz which are both rather high impedance values, so the 4047 oscillator will be much more suspect to switching noise than the 555 one. That is because a 555 can output larger current than 4xxx series, so the cap can be larger and the resistor lower for the same frequency, which makes it harder for noise to creep into the oscillator.
 
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