A Wideband Tuning Method for Extended Operating Frequency Range of Wireless Power Receiver

This paper proposes a wideband tuning method for extended operating frequency range of an inductive power transfer (IPT) receiver by exploiting the variable properties of multiple LC resonant tanks at different frequencies. A wideband-frequency compensation network is designed to simultaneously utilize the characteristics of LCL low-pass and CLC high-pass circuits within a certain range of frequency variations. Consequently, a unity ratio of the receiver output voltage to the secondary coil open-circuit voltage is achieved, and the receiver reflected impedance to the primary coil is approximately pure-resistive. A full mathematical model of the proposed receiver is derived to explain the principle behind the wideband operation, and a filter approximation-based design method is developed for quick practical implementation. The whole IPT system including the proposed receiver and a typical series-compensated transmitter is modelled to analyze the performance of the power receiver on the system operating frequency variations. A 10W wideband receiver is prototyped and tested within a frequency range of 100kHz to 200kHz, and experimental results show that the output voltage of the proposed receiver is equal to the secondary coil open-circuit voltage, and the reflected impedance to the primary coil is approximately resistive.