A Novel High-Current Planar Inductor With Cooling Fins Based on 3-D Printing

Abstract

This letter proposed a novel high-current planar inductor with cooling fins based on 3-D printing and its copper winding is 3-D printed by using selective laser melting technology. The 3-D-printed winding is designed for high-current applications based on 3-D space and can work as both winding and cooling fins. Compared with conventional printed circuit board (PCB) planar inductor, the proposed planar inductor not only has better performance, such as low dc resistance (DCR), ac resistance, and temperature rise, without volume increasing, but also has the superiorities of conventional PCB planar magnetics, such as ease of manufacture and controllability. To verify its performance, a 100-A-output buck converter using the proposed inductor was fabricated and compared with another identical buck converter using a conventional PCB inductor with the same size. The DCR of the proposed inductor is almost one-fifth of the PCB inductor. Besides, the efficiency of the buck converter with the proposed inductor is always over 0.5% higher than that with PCB inductor under different loads and its maximum efficiency is nearly 1% higher at light load. Furthermore, the maximum temperature rise of the proposed inductor is 26.8 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C under full load, only one-third of the PCB planar inductor. In other words, the proposed inductor can work well under 100-A current, whereas the traditional PCB inductor cannot due to too high temperature (103.8 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C).