12v DC-220v AC 20W inverter...

[baggio2]

hi...i have a project about inverter but i dont understand one point...how can i calculate transformer inductance(L1 and L2)...is there any formula to calculate these values...please help...

 

[Hero999]

At lease it's a reasonable power rating this time.
This will do the job, it's pure sine wave 200VA continuous but can do 275VA peak.
**broken link removed**

 

[baggio2]

i wont buy an inverter...i am designing it...so i need to calculate transformer inductance...please somebody help me...

 

[blueroomelectronics]

It'll cost you more to build a poor inverter than to buy a good one.

 

[baggio2]

it is my school project..i have to design it myself..please if u know the formula just write it....

 

[blueroomelectronics]

Do you have a schematic? How would we know what L1 & L2 do in the circuit.

 

[Boncuk]

Do you have a schematic? How would we know what L1 & L2 do in the circuit.

I'm guessing transformer primary and secondary inductance.

 

[baggio2]

here the schematic...

 

[GonzoEngineer]

Is that your design?.....I don't see any L1 or L2.

Do you meand the inductance of the Transformer?

 

[GonzoEngineer]

At lease it's a reasonable power rating this time.
This will do the job, it's pure sine wave 200VA continuous but can do 275VA peak.
**broken link removed**

Damn, Hero.....you guy's must be made of money in the UK? That price is outrageous!

 

[GonzoEngineer]

It'll cost you more to build a poor inverter than to buy a good one.

Only if you live in the USA and have a Radio Shack!

 

[Hero999]

It may be expensive but it's pure sinewave and most cheap inverters are modified sinewave.

 

[baggio2]

Is that your design?.....I don't see any L1 or L2.

Do you meand the inductance of the Transformer?

yes the inductance of the transformer...how can i calculate these values?

 

[Boncuk]

Hi baggio,

calculating the correct value of transformers is the job of those who produce them.

You plan to use 12V in and 220V out. Your design is a pure square wave inverter, so don't connect loads which are not designed for square wave AC.

The desired power output is 20W, which is 1.66A at 12V. Reverse a 9V/2.5A transformer with a center tap on the 9V-side. The first losses involved are the forward voltage drops of the 2N3055 of 0.7V. The second losses occur by the alternating magnetic field.

So using a 9V transformer will bring you pretty close to the desired output voltage.

Boncuk

 

[baggio2]

the output voltage must be 220V AC...but in my circuit it is 100 mV..how can i fix that mistake?please tomorrow time will be over....i need to design it today..could somebody draw it for me..?

 

[marvz]

the output voltage must be 220V AC...but in my circuit it is 100 mV..how can i fix that mistake?please tomorrow time will be over....i need to design it today..could somebody draw it for me..?

if you're problem is the only inductance of your transformer, why can't download an inductance calculator from the net. there's a lot of useful calculator in there...

 

[baggio2]

ohhh no..you dont understand me...i need the calculation values...it is my project and i am gonna give it to the inspector so if he asks how i found values? i need to calculate it myself...

 

[marvz]

Hi baggio,

calculating the correct value of transformers is the job of those who produce them.

You plan to use 12V in and 220V out. Your design is a pure square wave inverter, so don't connect loads which are not designed for square wave AC.

The desired power output is 20W, which is 1.66A at 12V. Reverse a 9V/2.5A transformer with a center tap on the 9V-side. The first losses involved are the forward voltage drops of the 2N3055 of 0.7V. The second losses occur by the alternating magnetic field.

So using a 9V transformer will bring you pretty close to the desired output voltage.

Boncuk

i agree with boncuk calculating the correct value of transformers is the job of those who produce them.

maybe you should wind your own transformer first. back to basics and find the right answer for your own.

 

[baggio2]

hmm..i guess i dont have problem with transformer...it is about driver circuit..can anyone draw a driver circuit for that inverter..please..i have just 2 days...

 

[blueroomelectronics]

What's wrong with the driver circuit in the schematic you posted?