Issue about winding the flyback transformer

[halisimon]

I am trying to wind the flyback transfomrer for energy storage purpose. The turning ratio is designed to be 1:1, since voltage boosting purpuse is not need.
basically, I used Ferrrite Torodial core FT114, 77(frequency ranging from 1KHz to 1Mhz), The winding on both primary and secondary side are designed to be 2.5 turns.

My question is, in order to reduce the leakage inductance, I think it will be better to wind both the primary and secondary on the same side of the torodial core, like winding in overlapping fashion. Is that ture?

I am expecting the energy stored in the primary side could be transfered to the secondary side as much as possible, since for energy storage application, high Q is no longer required. So anyone has experiences about the trnasformer specification: 6µH-6µH, 40 Khz, ernergy storage purpose.
anyone has any clue about that?

thanks

 

[VVV]

It seems the number of turns is very small.
What is the switching frequency? Can you give more details? Such as, how much energy you need to store?

 

[dfullmer]

Here is a flyback example with a transformer winding calculation. It is from Practical switching Power Supply design By Marty Brown.

Might help ....

good luck


dfullmer

 

[halisimon]

Hi VVV,

My switching frequency is 40Khz, which means during each 25µs period, the swiching on the primary side will be turned off, the maximum duty ratio I design is 0.6.
At each ON period, the primary side of the transformer will be charged up linearly by a 12V battery, and the peak current will reach 30A. However the switch on the secondary side won't let the current flow through in the secondary winding, so the energy will be stored in the transformer, when the switch on the primary side is switched off, the current will be draged down rapidly, and the change of the polarity on the secondary side will enable the current flow in the secondary side
I used the PWM switching fashion, so the average current in the primary side will be 6.4A. However the maximum power which is delivered to the secondary side at the maximum duty ratio is calculated as 108W. However the average power delivery is designed to be 50W.

The primary and secondary turn are both 2.5 turns(6µH) which is not alot. I choose the 20 AWG wire which will enable the 11A (continuous).

In my design, I used the ferrite toroidal core, 1.14 inch.

How do U think?

Thanks

HaliSimon

 

[jkmaro]

recalculate the magnetic field density produced , i think it will need to be increased by increasing the no of turns as ( LdI/Dt = N dQ/dt )
Q ---> Phi " magnetic field intinsity "