A high frequency model for Litz wire for switch-mode magnetics

An analytical model which characterizes Litz wire over a wide frequency range is derived. The model overcomes the shortcomings of previous efforts and predicts the useful frequency range where substantial improvement over solid wire exists. Since the local proximity effects in the strands are taken into account, the degradation in performance at higher frequencies is easily predicted. The maximum useful frequency is obtained and verified by measurements.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>