Maximum efficiency point tracking for resonant wireless power transfer

摘要

The use of wireless technologies to power devices has many practical benefits however it is commonly disregarded due to losses in transferring power in this way. The most common method for wireless power transfer is via Strongly Coupled Magnetic Resonances (SCMR), which transfers energy by using the mutual inductance between coils. Generally, to achieve a high efficiency wireless power transfer the transmitter frequency must match the self-resonant frequency of its power receiver. However, techniques in literature that continuously measure the self-resonant frequency of a working LC resonant circuit (i.e. the power receiver) have limitations. In this paper, a phase shift control based Maximum Efficiency Point Tracking (MEPT) hypothesis is proposed and examined. Finally, a prototype wireless power system that utilises this methodology is built to demonstrate that it can be used to successfully control a wireless power transfer system at its optimum frequency and hence achieve maximum efficiency.