Analysis and design of a novel cubic WPT system in a metal environment for an enclosed sensor scenario

This paper proposes a novel cubic WPT system for an enclosed sensor scenario, and its transmission characteristics in a metal environment have been analyzed. In addition, stable and high transmission efficiency can be normally achieved in all positions. The proposed quasi-double D coil structure is composed of two pairs of transmitting coils; each transmitting coil pair is placed face to face and connected serially. Through current amplitude modulation, magnetic flux can flow towards the centre of the receiving coil and keep the system high efficiency when the rotation angle of the receiving coil changes. However, the installation position of the receiving coil is not fixed in the switch cabinet application, and an irregular iron wall and the metal shell of sensors could also lead to inconsistent iron loss of multiple transmitters. To overcome the resulting disturbances in efficiency, the improved current amplitude control method and the optimal load have been theoretically deduced in the case of the position variation of the receiving coil in a metal environment. Finally, experimental results in two-dimensional space verify the omnidirectional transmission capability of the proposed quasi-double D coil, and efficiency disturbances are effectively alleviated.