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22nd November 2012, 13:14 #1
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need 12 v dc to 240v ac 500w inverter circuit
i want to make an inverter ckt of i/p vg 12v dc and o/p vg 240v ac , i need 2  3A current at o/p side.
and i wants to do it without center tap transformer and i can use 12v to 240v stepup transformer.

22nd November 2012, 13:20 #2
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Re: need 12 v dc to 240v ac 500w inverter circuit
Have you decided which controller you'll use? SG3524, SG3525, microcontroller or something else?
If you want to do it without center tap transformer, use fullbridge topology instead of pushpull.
If the transformer primary voltage rating is 12V, secondary rating of 240V won't be enough.
Hope this helps.
Tahmid.

22nd November 2012, 14:05 #3
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Re: need 12 v dc to 240v ac 500w inverter circuit
“Let the future tell the truth, and evaluate each one according to his work and accomplishments. The present is theirs; the future, for which I have really worked, is mine.” Nikola Tesla

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23rd November 2012, 09:32 #4
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Re: need 12 v dc to 240v ac 500w inverter circuit
thank u for reply,
I dont use any microcontroller, using a 555 ic convert 12v dc to 12vdc 50hz square wave and fetch it to 4013(d  f/f) ic to get 2 toggle signal of 12v 50Hz and then fetch these 2 signal to MJ11032 to amplify current which is connected to center tap transformer (12 to 240v step up) but am unable to get 25A(getting 12A)current at primary side pls help me..i need at least 2A at secondary.

23rd November 2012, 09:47 #5
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Re: need 12 v dc to 240v ac 500w inverter circuit
What transformer you have. Trafo core is enough big?
You should use several transistors in parallel to get higher current.
Post circuit.
   Updated   
Circuit is this :
http://farrukh2dayselectronics.blog...sing4013.html“Let the future tell the truth, and evaluate each one according to his work and accomplishments. The present is theirs; the future, for which I have really worked, is mine.” Nikola Tesla

23rd November 2012, 09:48 #6
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Re: need 12 v dc to 240v ac 500w inverter circuit

23rd November 2012, 09:53 #7
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Re: need 12 v dc to 240v ac 500w inverter circuit
“Let the future tell the truth, and evaluate each one according to his work and accomplishments. The present is theirs; the future, for which I have really worked, is mine.” Nikola Tesla

23rd November 2012, 10:03 #8
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Re: need 12 v dc to 240v ac 500w inverter circuit
At full power at lowest battery voltage (let's take that as 10.5V under full load), the current from the battery (assuming 80% efficiency of the inverter) is [(500/10.5)/0.8] = 59.5A.
Now, try to imagine the losses you will have when using power transistors. That's why it's suggested to use MOSFETs instead.
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23rd November 2012, 10:07 #9
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Re: need 12 v dc to 240v ac 500w inverter circuit
In other words, heat everywhere.
“Let the future tell the truth, and evaluate each one according to his work and accomplishments. The present is theirs; the future, for which I have really worked, is mine.” Nikola Tesla
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23rd November 2012, 12:01 #10
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23rd November 2012, 12:04 #11
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Re: need 12 v dc to 240v ac 500w inverter circuit
I think I have a few. I'll upload in a while.
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23rd November 2012, 17:40 #12
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Re: need 12 v dc to 240v ac 500w inverter circuit
can i use this ckt..
http://www.m0ukd.com/electronics/mod...wave_inverter/
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23rd November 2012, 17:43 #13
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Re: need 12 v dc to 240v ac 500w inverter circuit
You must have more MosFETs in parallel to handle needed power.
“Let the future tell the truth, and evaluate each one according to his work and accomplishments. The present is theirs; the future, for which I have really worked, is mine.” Nikola Tesla
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23rd November 2012, 17:48 #14
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Re: need 12 v dc to 240v ac 500w inverter circuit
is it necessary? can u explain what is the problem if i use single mosfet( data sheet shows it will give max 55A current)..............

23rd November 2012, 17:50 #15
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Re: need 12 v dc to 240v ac 500w inverter circuit
Also manufacturer datasheet tell on what temperature, usually they give data for 25C. Its hard to keep 25C of parts, where even ambient temp is over that. Marketing is amazing.
But best learning is if you try to make, theory is nothing without practical exams. When device get hot you can fast turn off, measure and monitor, and make conclusions.“Let the future tell the truth, and evaluate each one according to his work and accomplishments. The present is theirs; the future, for which I have really worked, is mine.” Nikola Tesla
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23rd November 2012, 17:56 #16
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23rd November 2012, 17:56 #17
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Re: need 12 v dc to 240v ac 500w inverter circuit
In post 8, I've shown that maximum current (average) will be 59.5A. Peak current is pushpull converter can be 1.4 times average current, which in this case will be 1.4 * 59.5A = 83.3A. You just crossed the current limit (by A LOT) before we even got to the power loss calculations!

23rd November 2012, 18:01 #18
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Re: need 12 v dc to 240v ac 500w inverter circuit
Thank u
How many MOSFETs I have to use for better performence(500watt).....

23rd November 2012, 18:07 #19
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Re: need 12 v dc to 240v ac 500w inverter circuit
Depends on the efficiency you want. Let's say you'll use IRF3205. Let's take RDS(on) to be a constant 8mΩ. Highest average current was calculated to be 59.5A. P = (I * I * R).
For simplicity, let's just consider the conduction losses.
If you use 5 IRF3205's in parallel in one leg, the RDS(on) is 1.6mΩ. Maximum power dissipation in the 5 IRF3205's is (59.5 * 59.5 * 0.0016)W = 5.6644W. If you use 4 IRF3205's instead of 5, power dissipation is 7.0805W. If you use 3 IRF3205's instead, power dissipation is 9.441W.
Decide which is okay for you. Then select accordingly. The lower the power dissipation, the lower the losses, the lower the heat, the higher the efficiency.
Hope this helps.
Tahmid.

23rd November 2012, 18:28 #20
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Re: need 12 v dc to 240v ac 500w inverter circuit
Consider usage of :
IRFP3206 60V 200A 2,4mOhm (around 12eur)
http://www.tme.eu/en/Document/f32728...rfp3206pbf.pdf
IRFP3077 75V 200A 2,4mOhm (around 12eur)
http://www.tme.eu/en/Document/378bda...rfp3077pbf.pdf“Let the future tell the truth, and evaluate each one according to his work and accomplishments. The present is theirs; the future, for which I have really worked, is mine.” Nikola Tesla
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