A Novel Self-adaptive Wireless Power Transfer System to Cancel the Reactance of the Series Resonant Tank and Deliver More Power

Wireless power transfer (WPT) is a promising technology to supply power in applications where physical contact is not available. Conventionally, both the primary side and the secondary side need resonant capacitor to increase transmission ability. However, the detuning of WPT systems caused by the component tolerance of inductors and capacitors and aging of the capacitors will decrease the system performance especially in very low coupling (k=0.05) applications. The delivered power is very sensitive to the reactance under very low coupling conditions, accordingly, a self-adaptive WPT system to cancel the reactance caused by the tolerance of inductors and capacitors in the primary and secondary is proposed. The novel concept uses an auxiliary circuit in series with the secondary, which can automatically compensate the reactance in the circuit, hence increases the system performance in terms of delivered power. This concept is applicable to both single- and multiple-pickup WPT systems. A prototype has been built and tested experimentally to validate the feasibility of the proposed concept.