Phase Shift Control Based Maximum Efficiency Point Tracking in Resonant Wireless Power System and its Realization

A modern Wireless Power Transfer (WPT) system is commonly realized by Strongly Coupled Magnetic Resonances (SCMR), which transfer energy by using the mutual inductance between coils. The application of wireless power transfer is critically limited by its energy transfer efficiency. SCMR systems are designed to transmit at a frequency that is equal to the self-resonant frequency of its power receiver, in applications where the self-resonant frequency varies during operation the measurement of the frequency is typically not possible. In this paper, a phase shift control based Maximum Efficiency Point Tracking (MEPT) approach is proposed along with implementation methodologies to enable real-world application. A prototype wireless power system with MEPT featured is built which verifies that the new MEPT method could effectively track the optimized frequencies continuously on the fly and maximise the efficiency of the WPT.