Additive manufacturing of planar inductor for Power Electronics applications

In an effort to simplify power electronics integration, we explored an additive manufacturing (AM) process, or commonly known as three-dimensional (3D) printing for fabricating magnetic components. A commercial multi-extruder paste-extrusion 3D printer was used to process both metal and magnetic pastes into 3D structures. We formulated a low-temperature curable Poly-Mag paste, which is a mixture of magnetic powder and a polymer, as a feed material for printing the magnetic core and used a commercial nanosilver paste for printing the winding. After the structure was printed, it was cured at 250°C for one hour without any external pressure to form the magnetic component. The nanosilver paste can achieve a crack-free single layer thicker than 100 µm and the electrical resistivity of the printed winding was about three times higher than that of bulk silver. This is because of the low curing temperature resulted in a lower density than the bulk. The relative permeability dispersion of the 3D printed toroid core had a bandwidth up to 10 MHz with a static relative permeability of about 10. Both the winding and core magnetic properties will be improved by adjusting the feed paste formulations and their flow characteristics and fine-tuning the printer parameters, such as motor speeds, extrusion rate, and nozzle sizes.