Research on Uniform Magnetic Field Compensation Structure of Array Circular Coils for Wireless Power Transfer

In a wireless charging system, non-alignment has been a big problem that affects the transmission efficiency. The uniform magnetic field can ensure the charging power stability and extension of battery life in a multi-load wireless charging system, which also expands the free charging area of the loads. In this article, the array circular coils of wireless power transfer (WPT) with a compensation structure have been proposed, which can be obtained by analyzing the magnetic field trajectory of the elementary unit of the array coils. Larger scale of the uniform magnetic field could be expended by the joint of several elementary units. The correctness and validity of the structure are verified by theoretical derivation and finite element simulation. Besides, the compensation method could be used for any forms of array coils.