3 kVA 12 Volts DC to 230 Volts AC inverter circuit

Discussion in 'The Projects Forum' started by nikhilsonar29, Jan 22, 2015.

Sep 26, 2014
68
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hi eric sir,good after noon
sir i have new project to design
i want to design simple inverter circuit
following are the specification
12 volt dc battery to 230volt ,power=3KW
can you plz suggest me the concept for it
Aim:-when the lift in its operation and in between if light will off then, lift get suddenly stop at that level,
so from that level we should have to take the lift nearest possible level,so for that what i am thinking
firstly we will charge our 12 volt battery ;battery will continously charge during normal mode(i thinnk i will need series of battery);and when light will off then
lift will automatically shifted on backup mode where the 230 volt ac will given by the battery (12volt to 230 v ac,after inversion) ;in backup mode ,inverted 230 volt ac will only need for 1 min ,to reach at nearest level.
hope you get the concept
Thanks and Regards
NIkhil

2. ericgibbs AAC Fanatic!

Jan 29, 2010
2,503
380
hi Nikhil,

Using a 12V battery to supply a 3000Watt 230Vac load is not a simple task, other members may have already have built such a unit.

E

Sep 26, 2014
68
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sir,
plz find the attachments
attached image is of 3kva inverter circuit dig
i jst wanted to know the specification of following component from circuit which i did not undestand
1) D1 i.e.diode ;is it zener or simple and whitch is its positive terminal
2)plz tell me the rating of resistor used (half watt or qurter watt or...)
3)i want to know details of transformer used ,means is it center tap ,step up ?if possible plz tell me which transformer should i use.
4)how many battery and waht rating of battery (amp hour rating) should i used

Thanks and Regards
Nikhil Sonar

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Sep 26, 2014
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hi every one...good morning
diode shown at transformer stage is said to be have 20 -25 amp diode ,
any one can plz tell me that which diode should i use,
means it number(like 1n5820) and its type(simple or any special type)

5. Ramussons Active Member

May 3, 2013
557
92
Do you realise that you are going to be handling more than 300 Amps from that 12 volt battery?

Sep 26, 2014
68
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let me update new design.which is updated where the previous one i got
plz find the attachments

the update is at power transistor stage

"each TIP36 will be able to handle 25amps....so just keep adding as many as you want and multiply the specs for the desired output....in the shown diagram 5nos are shown which constitutes a max output of around 25 x 5 x 12V = 1500 watts, for 24V batt it would be 3kva, with a 48V batt it would be 6kva and so on"

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Sep 26, 2014
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8. Alec_t AAC Fanatic!

Sep 17, 2013
5,791
1,103
You can do a parametric search for power/switching/general-purpose diodes of that rating on the website of any major stockist (e.g. Farnell, Mouser, Digi-key .....). Personally I think that, depending on the heatsinks you use, you'll need a higher rating. As per post #5, the transformer peak primary current will be >300A !! Each of those diodes has to withstand >300A briefly when the primary coil current switches off.

Sep 26, 2014
68
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hi ....good morning
as per my calculation of power consumption after power failure by lift (it include motor,lights in lift and drive ) is total about 2.89 kva.
so i have choose 3kva inverter
and also plz note that,only 2 -3 min are required after failure to take lift to its possible nearest floor (means we want standby power supply for only 2-3 min)
can any one plz tell me about selection of transformer?

10. Ramussons Active Member

May 3, 2013
557
92
Do you have to run the hoist motor for this? How about physically coupling a 12 V motor to the main rotor shaft to do this?

11. tcmtech Well-Known Member

Nov 4, 2013
2,034
1,651
I have serious doubts on your design given the parts listed plus the fact that a 2.89 KVA motor is likely to have a starting surge power 3 - 5 times that which is going to be way beyond your designs capacity or any typical single 12 volt batteries capability.

#12 likes this.

Sep 26, 2014
68
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yes that's very right sir,
but here in my problem we gives supply to motor by means of vfff drive,
during power failure motor will run on low frequency and low speed as compare to its normal operation.,which is decides by our vfff drive
in short there Is no need to worry about surge power,
and the consumption will be between 2.5 to 3 kva through out constant

13. Dodgydave Distinguished Member

Jun 22, 2012
4,979
744
I dont see the point of Ic2, and Ic4, your using a cd4017 counter clocked at 50hz with a 555 timer, why dont you use Tl494 deadicated Ic.

http://www.ti.com/product/tl494

Last edited: Feb 10, 2015
14. kubeek AAC Fanatic!

Sep 20, 2005
4,670
804
Wouldn´t it be easier to let gravity move the lift any the direction it wants, and just apply brakes gently to let it move there slowly and then stop?

Sep 26, 2014
68
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yah...@kubeek,
that will be very cool idea,
but
we had already discuss on that but it is not that simple to implement .
with the varying load there will be different speed to the lift..so we will be not having proper control on speed of lift
so there must be standby power supply to have control on lift

Sep 26, 2014
68
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@Dodgydave
thanku sir
I will try for that
and if possible you r having circuit diagram that how do I achive that by means of TL494,plz suggest me

Jun 22, 2012
4,979
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18. tcmtech Well-Known Member

Nov 4, 2013
2,034
1,651
I see. Since you have a VFD unit that changes things.

To be honest the simplest way to make your system work would be to get into the VFD's main power circuitry and feed higher voltage DC power directly to it which could be done by either using a lot of smaller batteries in series or using a cheap power inverters intermediate internal high voltage DC stage as a power source.

Personally what I am seeing here is a potential for a lot of time effort and money to be spent (More than what buying a good used 3 KVA power inverter or UPS unit would cost) just to avoid using the stairs or to avoid buying a properly sized generator.

19. kubeek AAC Fanatic!

Sep 20, 2005
4,670
804
I think this is supposed to be "in case you get suck in elevator" not "in case power goes down and you need to get to another floor".

20. tcmtech Well-Known Member

Nov 4, 2013
2,034
1,651
My curiosity with this is how many other parts of the control systems also need power to operate besides just the main motor where using a properly sized and installed UPS system (even if its a used and repaired one) would be the wiser choice.

To me the whole DIY inverter concept plus how ever it would be hooked into the power system and operated just comes off as poorly thought out whereas a properly sized and set up UPS unit would give seamless and proper operation.