Now let’s open a new project and pickup the XFRM_NONLINEAR model from the BREAKOUT library:
Place the component, select it, mouse dx button/Edit Properties
the property window pops up
write the name of implementation and the path to the library
Report the number of turns of primary and secondary, for example L1_TURNS=29 and L2_TURNS=4
Write tha name of model on the Value property
To calculate the leakage inductance, assuming a primary inductance L1 of 90.4uH, we have before calculate the coupling factor K
K = SQRT( 1-Lps/Lpo)
where
Lps is the primary inductance measured with the secondary inductance shorted
Lpo is the primary inductance measured with the secondary inductance open unconnected.
assuming to obtain k = 0.99, the leakage inductance will be
Lleak = Lp*(1-k^2)
In our case Lleak is 1.79uH.
Calculating in 50mOhm the resistance to the primary, our dual winding transformer model can be this:
9. Bibliography
1. FERRITES and Accessories, Siemens Matsushita Components
2. Soft FERRITES – Data Handbook, Philips Components
3. O. Kilgenstein, Switched-Mode Power Supplies in Practice, John Wiley & Sons
4. H.W. Whittington, B.W. Flaynn, D.E. Macpherson, Switched Mode Power Supplies, John Wiley & Sons
5. R. Martinelli, C.Hymowitz, Magnetic Design and Modelling, Power’s Specialit’s
6. Intusoft, Magnetic Designer, Intusoft, 1997
7. M. Pezzi, Campi elettrici, magnetici e circuiti, Zanichelli Bologna
8. S. Ramo, J.R. Whinnery, T. Van Duzer, Campi e onde nell’ elettronica per le comunicazioni, F. Angeli, Milano
9. Technical Standard CEI EN 60950, 1996-10
10. Technical Standard CEI EN 60950/A4, 1997-10
11. Web site 135.145.4.41, New England Electric Wire Co, Technical Information
12. Web site http://www.wiretron.com, Litz wire – general information
13. Web site http://www.neewcweb.com, New England Electric Wire Co.
14. Web site http://www.dartmounth.edu/~sullivan/litzwire/litz.html, CR Sullivan, optimal choiche for Number of Strand in a Litz-Wire Transformer Winding, PESC’97
15. Web site http://www.piremag.com, Pirelli Magnetic Wire.
16. Magnetic Core and BH Curve, OrCAD PSpice A/D, OrCAD PSpice AA and AMS Simulator, Wei Ling