Additive Manufacturing of Toroid Inductors for Power Electronics Applications
The integration of power inductors and transformers, as illustrated in Fig. 1(a), is chal-lenging due to the large core volume or unconventional geometries used to distribute flux or control coupling. Commercial magnetic components consisting of cores and windings are fabricated separately and then assembled, as shown in Fig. 1(b). This manufacturing approach gives rise to bulky discrete components and precludes the implementation of high-density, high-performance integrated geometries. For example, the uniform-flux magnetic component structures shown in Fig. 1(c) cannot be fabricated by the current manufacturing processes. Thus, to improve the power conversion efficiency, power den-sity, and reliability of a power electronics system, there is a need for manufacturing technologies that ease integration of the magnetic components.
Additive manufacturing (AM) or three-dimensional (3D) printing is a layer-by-layer process of making products and components from a digital model. Some key benefits of AM are shorter lead times, mass customization, reduced part count, ability to manufacture more complex shapes, less material waste, and lower life-cycle energy use. Recently, some research groups have explored the application of AM in power electronics. The purpose of this work is to explore the feasibility of using a 3D-printing process for fabricating magnetic components that consist of both magnetic cores and conductive windings. We chose to work with a multi-material extrusion-based 3D printer because it offers the ease and flexibility of co-processing multiple materials, and for feedstock we can leverage our research expertise in the formulation of pastes of metal and magnetic + poly-mer composites. Use of paste as the feedstock also reduces material waste, lowers the equipment cost, and simplifies the part construction process. The paste-based additive process can be readily scaled up to manufacture a multi-material and multi-functional system. Thus, this process platform offers the potential for further integration of a power electronics circuit by concurrent manufacturing of capacitive, magnetic, and resistive components.