An improved AC loss model for the optimization of planar-coil inductors

This paper presents a computationally efficient method for calculating ac winding losses in planar-coil inductors. This loss model is employed in a multi-objective optimization algorithm to determine inductor designs which minimize power loss while maximizing power density. The ac winding losses in the optimized inductor designs are compared to finite-element simulations - as well as to estimates from other loss model approaches - and exhibit less than 7% error across the tested optimized designs. The loss model additionally provides the designer with an understanding of how to reduce ac conduction losses by balancing the current distribution in each turn of a winding.