UPS designing. where to start?

[qaseemiqbal]

Hi,

I have decided to design a UPS for my home. I am aiming for 2kVA UPS. Now the thing is where should I start. Is there any book for ups out there. I have made quite a search on the internet but most of the data I found was either out-dated or incomprehensible. For example the inverter circuit I found was of 1998 (https://www.tldp.org/HOWTO/UPS-HOWTO/index.html). So, if I am willing to design 2kVA 12 V DC to 220 VAC, where can I find the necessary documents and information.

 

[rajudp]

2kva at 12v is not good design it takes 167+ amp from battery, better go go for 24 -48v design

 

[pranam77]

Hi, I have decided to design a UPS for my home. .

Are you seriously involved in "designing" of a UPS of your own design? or just wanna assemble? There quite a lot of kits available by which you can assemble your own UPS. If you are really keen about designing, do you think about re-inventing the wheel while the market has flooded with the best ones?

 

[Tahmid]

Hi,
First you need to change the supply from 12v to maybe 48v.
Then, you need to become familiar with SG3525 or SG3524, LM339, 4N35 or similar PWM chips, comparators, optocouplers. Then you need to go about deciding what or how you are going to do at each section of the circuit, eg. battery charging, hicut, locut, overload cut, feedback, etc.

Hope this helps.
Tahmid.

 

[qaseemiqbal]

@rafudp

Thanks for your advice. I'll be taking it into consideration.

@pranam77

its more sort of assembling with detailed study of components, not just simply putting the pieces together without knowing anything about it. So its a bit of both designing and assembling.

@Tahmid

it means I have to study DC-DC converters, PWM and then take it from there?

 

[Tahmid]

Hi,
Yes, you need to study PWM and then go on to comparators, optoisolators, phase angle control and so on.

You can start with the SG3525 datasheet and related application notes and documents.

Hope this helps.
Tahmid.

 

[aminkath]

First you get data sheet of SG-3524 PWM IC I,m already try and make one kit with output volt control example if you set backup volt ac 240 without load and add some 100 or 200 watt load output ac volt always balance and this kit acceptable with power transistor and power mosphet

 

[pnjbtr]

first of all purchase transformer from market.In ups transformer is moxt expensive than all other things like control board and transistors or fets.
You should assembel your ups with 24volts.(because with 12volt it is difficult for beginers and difficult to control much hevy wire almost 25mm square )
And you need two batteries.
If you assemble with 24volts you only need 12 to 16mm square flexible copper wire.

 

[RCinFLA]

After learning all the previous mentioned items, a UPS supply is syncronized to the AC grid. This allows it to switch over to battery backup within one cycle. Switching back when AC grid shows back up is tougher as inverter phase has walked away from original grid so it must be slowly slewed back to grid sync before switching back onto grid

Do you need a true sinewave backup or will a modified sinewave (modified squarewave) output do? Most inexpensive computer UPS are just modified sinewave output.

If you intend to run any AC motors (like a refrig compressor) I would recommend a true sinewave inverter.