Analysis and Design of Multichannel High-Frequency Wireless Power Transfer System Based on Load Impedance Compression

Miniaturization is one of the main trends in the development of power supplies. High frequency helps to improve the flexibility of the magnetic field space of wireless power transfer (WPT) technology, making it more suitable for multi-load application scenarios. However, it will also increase the sensitivity of the system, causing mutual coupling problems in multi-load designs. To this end, this paper proposes a load impedance compression mechanism for wired/wireless dual-load applications, adding an impedance conversion network to adjust the branch impedance value. From the perspective of impedance trajectory, the influence of the change in coupling coefficient is compressed, the complex and intertwined trajectory curves between multiple loads are decoupled, and the independence of load power is restored. Meanwhile, based on the traditional secondary side design method, a coil and rectifier impedance trajectory constraint model under variable coupling coefficient is further proposed. Finally, the influence of different power amplifier output filtering conditions on the load branch is analyzed, and the overall design process is given.