Compensation Network Design for WPTS With Independence Coupling Coefficient in CC and CV Modes With ZPA, and Its Simplest Network

Wireless power transfer systems (WPTS) have found extensive applications in battery charging. To achieve optimal charging performance, several requirements must be met. First, it is necessary to simultaneously achieve constant current (CC) and constant voltage (CV) charging modes using the same compensation network, while maintaining zero-phase angle (ZPA) at the input impedance. Second, it is desirable for the charging modes to remain unaffected by the coupling coefficient (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i>). Third, a systematic and straightforward method is needed to design the compensation network topology and parameters. In this article, we propose a novel systematic compensation network design method that fulfills all three requirements for the first time. The method represents the magnetic coupling transformer and the compensation network as a series of cascaded T-type modules. By analyzing the requirements for achieving CC or CV modes with ZPA conditions in the basic T-type module and extending these requirements to multiple T-type modules, the parameters of the compensation network can be determined. This approach enables the identification of a series of compensation networks that simultaneously achieve CC and CV modes with ZPA characteristics, independent of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i>. Additionally, we introduce a simplified compensation network, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLCC-S</i>, which satisfies the aforementioned requirements with least compensation components. Numerical simulations and experimental results are provided to validate the effectiveness of the proposed compensation network. The results demonstrate the network's ability to achieve the desired CC and CV modes with ZPA features, irrespective of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i>.