Additive Manufacturing of Toroid Inductor for Power Electronics Applications

To increase power density and simplify the process of integrating magnetic components to power electronics circuits, a commercial multiextruder paste-extrusion three-dimensional (3-D) printer was used to process both metal and magnetic pastes into 3-D structures of magnetic components. A magnetic-filled-benzocyclobutene composite, termed poly-mag paste, was formulated and used as a magnetic core feedstock for the printer, and a commercial nanosilver paste was used as a conductive winding feedstock for the printer. A toroid inductor was 3-D printed by using metal and magnetic pastes, and it was cured at 250 degrees C for a half hour without any external pressure to form the structure. The inductance of the 3-D-printed toroid inductor was measured to be 167-143 nH in the frequency range of 1 kHz to 3 MHz. The dc resistance of the winding was 0.1 Omega. These results are in good agreement with a finite-element analysis simulation. Both the winding and core magnetic properties can be improved by adjusting the feed paste's formulations and flow characteristics, and by fine tuning the printer parameters, such as motor speeds, extrusion rate, and nozzle sizes.