Investigation on Flexible Coils Geometries for Inductive Power Transmission Systems

Wireless power transmission systems via inductive link provide nowadays an interesting option for charging devices wirelessly. The power transmission can be realized by using a couple of coils placed in proximity of each other. These coils may differ in their materials, technology, and geometries. In this paper, an investigation of different flexible coils geometries has been carried out. In fact, we investigate circular, square hexagonal and octagonal shapes with similar design parameters such as an internal radius of 2.4 cm, an external radius of 4 cm and six turns. The coils comparison is based on the measurement of the self-inductances and quality factors of the coils in different situations, such as number of used coils sides, damping and ideal states. The results show a similar behavior of the singular and dual-sided coils. The highest coil's quality factor was in the case of a circular coil shape, whereas the highest self-inductance was in the case of a square coil shape. The coil with circular shape shows the lowest self-inductance and quality factor variation in the case of maximum coil damping.