Method and apparatus for adjustable coupling for improved wireless high Q resonant power transfer

#The described technology generally relates to wireless power. More specifically, the disclosure is directed to methods and apparatuses for adjustable coupling for improved wireless high Q resonant power transfer.

#Modern portable electronics devices have become more capable, including higher performance battery power sources while consuming lower power. Due to this enhanced capability and always-on availability, consumers have come to depend on portable electronics devices (e.g., telephones and computers) for all manner of tasks. Because consumers are accustomed to continuous availability of devices, it is desirable that associated batteries be wirelessly rechargeable. Inductive wireless power transfer has become the preferred solution for providing wireless power. Similarly, battery powered electric vehicles are becoming more popular as a solution to counteract rising levels of air pollution and the depletion of fossil fuels. One roadblock to further market penetration of electric vehicles is a requirement of routinely connecting a heavy power cable to the vehicle. Wireless charging by inductive power transfer is the preferred solution for stationary charging and the only solution for charging on-the-go. Inductive power transfer is improved by resonating coupled inductors in the power transmitter and the power receiver. In addition, highly resonant inductors are able to couple power over longer distance and do so more efficiently. Accordingly, methods and apparatuses for adjustable coupling for improved wireless highly resonant inductive power transfer are desired.

#An apparatus for wireless inductive power transfer is provided. The apparatus comprises a primary resonator configured to wirelessly transfer power to a secondary resonator coupled to a load of a wireless power receiver. The apparatus comprises a coupling circuit configured to couple energy from a source power supply to the primary resonator. The apparatus comprises a controller configured to coordinate an adjustment of a first amount of coupling between the source power supply and the primary resonator, via the coupling circuit, with an adjustment of a second amount of coupling between the secondary resonator and the load of the wireless power receiver.

#FIG. 1 illustrates an exemplary inductor coil wire in which skin effect may be observed.

#FIG. 2 illustrates an exemplary model of an electrical resonator.

#FIG. 3 illustrates a bell as a model of an exemplary physical resonator.

#The various features illustrated in the drawings may not be drawn to scale. Accordingly, the dimensions of the various features may be arbitrarily expanded or reduced for clarity. In addition, some of the drawings may not depict all of the components of a given system, method or device. Finally, like reference numerals may be used to denote like features throughout the specification and figures.

#The detailed description set forth below in connection with the appended drawings is intended as a description of certain implementations of the invention and is not intended to represent the only implementations in which the invention may be practiced. The term “exemplary” used throughout this description means “serving as an example, instance, or illustration,” and should not necessarily be construed as preferred or advantageous over other exemplary implementations. The detailed description includes specific details for the purpose of providing a thorough understanding of the disclosed implementations. In some instances, some devices are shown in block diagram form.

#Wireless power transfer may refer to transferring any form of energy associated with electric fields, magnetic fields, electromagnetic fields, or otherwise from a transmitter to a receiver without the use of physical electrical conductors (e.g., power may be transferred through free space). The power output into a wireless field (e.g., a magnetic field or an electromagnetic field) by a “transmit antenna” or “primary resonator” may be received, captured by, or coupled to a “receive antenna” or “secondary resonator” to achieve power transfer.