The Potential of 3D-MID Technology for Omnidirectional Inductive Wireless Power Transfer

International audienceOmnidirectional inductive wireless charging system of a mobile is studied. Instead of using conventional planar coils printed on circuit boards, 3D Molded Interconnect Device (3D-MID) coils are used. The receiver is a single piece that has 3 elliptic inductors pointing in 3 different directions of the space. A half meter cubic box with 4 planar emitting inductors on 4 sides is used to transmit power at 6.78 MHz to the receiver inside the cube, regardless to the position and orientation of the receiver. Measurement results show that the 3D-MD receiver can get a power of 1.4 W at 7.9% efficiency on most of the positions inside the box. When the receiver is at the central position and also in the corners of the box, there is little variation of the transferred power when the receiver turns 360°, which means that it is almost insensitive to angular misalignment. However, when the receiver moves from the center towards the corners, there is a drop or an increase of power, which means that there is a lack of uniformity of the power which transferred near the corners. Ways to improve this point are discussed. However, our conclusion is that 3D-MID technology is an interesting technology for replacing the planar coils used in conventional WPT receivers