Omnidirectional inductive wireless charging of a 3D receiver cube inside a box

Omnidirectional inductive wireless charging of a $6\times 6\times 6 cm^3$ 3D receiver cube with 6 planar coils inside a $47\times 47\times 47 cm^3$ box with 4 planar emitting coils is studied. The power delivered to the cube in the central position of the box is in the 1 W - 2.4 W range with 6 - 7% transfer efficiency. In this position, the power is insensitive to the pitch angular orientation. When moving the 3D receiver cube toward the corners of the box, there is no sudden drop of transmitted power. However, the delivered power near the corners increases or decreases in an acceptable range depending on the orientations of the magnetic field of the emitters. Perspectives of this work, when replacing the manufacturing of coils based on PCBs technology by 3D Molded Interconnect Device technology, are briefly discussed.