Calculating windings of pulse power transformer
In old magazine (Radio - Радио) I found small article about calculating PWM power transformers. The formulas are for toroid core transformers, but I think, they are usable in standard E core transformers too.
1. Calculate the power of transformer: Pt=1.3*ΣPn , W. The power of transformer is sum of all output powers multiplied by 1.3.
2. The core max power: P=Sc*So*f*Bmax/150 , W. f=Hz, Sc=area of core section in cm2, So=area of the “hole" in cm2. Bmax= max induction in Teslas, from core datasheet.
3. Number of turns in primary winding: w1=0.25*104*U1/fBmaxSc , in turns.
4. Max current in primary winding: I1max=P/ηU1 , A. (η = ~0.8)
5. Diameter of wire: d1=0.6*√I1max , mm. diameter is equal 0.6 multiplied by square root of max current.
6. Secondary (ant other) winding: w2=w1*U2/U1 , in turns.
