Planar inductor with quasi-distributed gap core and busbar based planar windings

Inductor design is investigated for battery charger used in plug-in hybrid vehicles. The inductor is designed to be implemented at the input and output parts of prototype charger (operation at 250 kHz) under development. Circuit simulations revealed inductor resistances at DC, 60 Hz and 500 kHz are the most dominant factors determining inductor efficiency. To reduce DC resistance, high density winding structure based on planar busbar stacking is proposed. To reduce AC resistance, quasi-distributed gap core configuration is investigated. A conventional concentrated gap configuration with E-E core pair and a custom-assembled quasi-distributed gap core set are compared. Each prototype was fabricated and characterized with impedance analyzer. Our new prototype made by a combination of busbar winding and quasi-distributed gap configuration demonstrates the best performance at DC and 500 kHz, and thus, the best structure for the application herein.