An Investigation into the Impact of DC Bias Conditions on Ferrite Core Losses

Switch mode power supplies are the predominant form through which power conversion is currently implemented in electronic equipment. Within such power supplies magnetic components that are placed under DC bias conditions are typically large and have relatively high losses. The nature of the ferrite core losses of magnetic components under DC bias conditions is not widely understood, and research in this area has been hampered by the difficulty of performing accurate core loss measurements. This paper reviews previous studies on the nature of core losses under DC bias, and presents new results, measured using a technique that has not previously been utilized for the measurement of core losses under DC bias conditions, which show that ferrite core losses increase significantly with an increasing DC bias.