Distance Extension of S-PS Wireless Power Transfer System Based on Parity-Time Symmetry

The application of wireless power transfer (WPT) has become more and more extensive, and the parity-time (PT) symmetric principle has been proved to significantly improve the degree of freedom of the WPT system without increasing the control complexity. However, the PT-symmetric region of the original WPT system with series-series (SS) compensation is limited. To overcome this drawback, a novel PT-symmetric WPT system with series-parallel-series (S-PS) compensation is proposed in this brief. The PS compensation network is converted to the S compensation network by equivalent circuit method. Then a mathematical model of the proposed system is established by circuit theory. It is found that the critical coupling coefficient of the proposed system are much smaller than the original PT-symmetric system. Furthermore, the proposed system has a compromise between transmission distance and transfer efficiency by setting the capacitance distribution ratio. A 26W prototype is built to verify the feasibility of the proposed method. Experimental results demonstrate that the proposed method doubles the transmission distance and improves the output power.

Automated summary

The application of wireless power transfer (WPT) has been expanding and the use of parity-time (PT) symmetric principles have proven to enhance the WPT system without increasing complexity. However, the PT-symmetric region of the original WPT system is limited. To overcome this, a novel PT-symmetric WPT system with series-parallel-series (S-PS) compensation is proposed. A mathematical model is established and it is found that the proposed system has a smaller critical coupling coefficient and a compromise between transmission distance and transfer efficiency can be achieved. An experimental prototype verifies the feasibility and demonstrates improved transmission distance and output power.