Additive Manufacturing of 10 W Power Converter with High Power Density

Achieving high power density for power electronics applications such as flyback AC/DC power converters requires three-dimensional integration of active and passive components, especially when using industry standard parts. 3D printing provides the flexibility to fabricate various plastic carriers from different materials without the need for expensive tooling, while still enabling complex structures for electrically, thermally and mechanically optimized setups. This paper presents a 3D integrated 10 W AC/DC flyback converter using additive manufacturing compared to the conventional planar PCB approach. The additive manufactured plastic structure combines the qualities of a heat sink, isolator and mechanical linkage. Furthermore, passive components are optimized in volume through rigorous selection. Ceramic capacitors are exclusively used, because the cuboid shape is perfectly suited for a high degree of 3D integration while parasitic losses are reduced in comparison to electrolytic capacitors. For efficient component placement and sufficient power dissipation budget, the converter housing is cube shaped with structured surface. All active and passive components are completely enclosed in the plastic additive manufactured structure, which improves the thermal connection. To avoid internal and surface hotspots, the filament selection and positioning of the heat sources is optimized by means of thermal 3D-FEM simulation. The 3D integration of the components results in 252 % higher power density in comparison to the conventional planar designs, maintaining the same functionality with identical commutation cell and magnetics. The comparative measurements are performed in DC/DC converter operation at 325 V input and 12 V output up to an output power of 10 W.