Assessment of Cost Factors Impacting Planar Magnetic Windings

Planar magnetics are being actively explored in a wide range of power electronics applications, with argumentation of their low cost being a key aspect of their popularity. However, unlike conventional wire wound magnetic components, their costs do not scale convincingly with volume owing to a strong dependence on manufacturing complexity. This paper assesses the cost factors impacting the design of planar magnetic windings. This is done qualitatively, through direct manufacturer survey, and quantitatively by presenting a cost modelling approach derived from cost quotations of exemplar planar transformers. The developed model fits excellently to the data it was trained on (6.5% error). It is shown to have good predictive power on designs that are well-represented by the training data (though not in the training set, 13% error), and reasonable performance (20-58% error) on designs which have limited representation in the training data.