Review of Transformer Fundamentals

Assumptions same as for inductor Starting equations H1Lm Nil H2Lm N2 Ampere's Law HmLm H1 - H2 Lm N1I1- N2I2 MmHm Bm linearized B-H curve Faraday's Law Net flux f f 1 - f2 MmHmA Results assuming pm i.e. ideal core Cross-sectional l m mean path ng area of core A Cross-sectional l m mean path ng area of core A

Proximity Effect Further Increases Winding Losses

Proximity Effect Inductor

Proximity effect - losses due to eddy current generated by the magnetic field experienced by a particular conductor section but generated by the current flowing in the rest of the winding. Design methods for minimizing proximity effect losses discussed later. Pw Pdc Pec Pec eddy current loss. Pw Rdc Rec Irms Rac Irms Rac FR Rdc 1 Rec Rdc Rdc Minimum winding loss at optimum conductor size. High frequencies require small conductor sizes minimize loss. Pdc kept small by putting may small-size...

Core Database Basic Inductor Design Tool

Interactive core database spreadsheet-based key to a single pass inductor design procedure. User enters input specifications from converter design requirements. Type of conductor for windings round wire, Leitz wire, or rectangular wire or foil must be made so that copper fill factor kcu is known. Spreadsheet calculates capability of all cores in database and displays smallest size core of each type that meets stored energy specification. Also can be designed to calculate and display as desired...