T18.7 - Split-PCB Planar Inductor Design for High-density High-efficiency Power Converters

Magnetic components often contribute to a significant portion of both the volume and power loss in power converters. This paper proposes a split-printed-circuit-board (split-PCB) design approach for planar inductors, which achieves a significant reduction in winding loss compared to a single-PCB design by mitigating fringing flux and proximity losses. The resulting decrease in total inductor loss enables smaller thermal management and higher power density. Both single-PCB and split-PCB planar inductor designs are modeled in Ansys Maxwell, and their performance is compared. Experimental validation is performed using a 40kW boost converter at input voltages of 100V, 120V, and 150V, with ac ripple currents of 40A, 50A, and 60A, respectively, operating at a light load with an average input current of 9A and a switching frequency of 200 kHz. The experimental results confirm that the proposed split-PCB planar inductor achieves a 35% reduction in total converter loss compared to a conventional single-PCB planar inductor when the boost converter is operating at the input voltage of 150V, the output voltage of 288V, and the ripple current of 60A.