Analytical Model of a 25-50 m Robust Single-Wire Electric-Field Coupling Power Transfer System Using a Limiter

A 25-50 m robust single-wire electric-field coupling power transfer (ECPT) system using a limiter is presented. Extending the transfer distance is always the key issue in energy transfer fields, whereas the distance of wireless power transfer systems is limited to several meters. On the other hand, characteristics of the traditional single-wire ECPT systems are very sensitive to the transfer distance. Solving these problems, in the range of tens of meters, the proposed scheme can eliminate the decrease of the transfer efficiency and variation of the output power without any tuning, which realizes strictly stable and long-distance energy transfer. The coupled-mode model of the system is built first, and then the transfer performances are analyzed. The modal solutions and action mechanism of the system are specified. Furthermore, the parameter design method to realize target efficiency and critical distance is also presented. A circuit model is built to verify the theoretical analysis. Simulated results indicate that, within the critical distance, the proposed system can achieve energy transfer with constant efficiency of 50% and constant output power of 4.1 kW, which does not need any tuning. Besides, the critical distance can be achieved from about 25 m to 50 m by adjusting the system parameters.