I have problem in this h bridge when i connect the two h bidge in series the circuit does not work but when i run each one by itself it works ok so what is wrong in connecting the two in series like this (i use pwm and it has two output a and b i use uc 3526)
and l1 and l2 is primary of the transformer
thanks

 

What means "does not work"?

You have 2x L1 and 2x L2. Which one is it?

Please indicate winding direction of the coils. (with a point)

 

What means "does not work"?

You have 2x L1 and 2x L2. Which one is it?

Please indicate winding direction of the coils. (with a point)

both the same(L1 AND L2) I JUST DRAW IT TO SHOW THAT THEY ARE WIRED ON THE SAME CORE, I MARK THE START BY BLACK DOT
AND IT DOES NOT WORK MEAN THAT THE SECONDARY HAS ZERO OUT PUT VOLTAGE AND ALSO THE INPUT CURRENT IS ALMOST ZERO

 

You have L1 and L2 separated on the left (in the bridges) . Then they are connected in series on the right (transformer). Are these two coils connected directly or not?

 

you have l1 and l2 separated on the left (in the bridges) . Then they are connected in series on the right (transformer). Are these two coils connected directly or not?

sorry i fix it in the diagram they are not connected in series in the left

 

The voltages should indeed add and not cancel the way you drew it.

1. What model are those IGBTs?
2. You are using 2 driver ICs, right? With their own references/power supplies.
3. Can you show the rest of the driver circuit?