Dual-band Resonant Coupling For Simultaneous Transmission Of Power And Information

Wireless power transfer technology has been applied commercially in manyfields, and in some applications such as human implantable devices and wirelesssensor network, the simultaneous transmission of information are often required totransfer control instruction or feedback system status. This thesis put forward akind of dual-band resonant coupling structure, this structure can offer two separatebands respectively used for power transmission and communication, guarantee thepower transfer performance and realize faster communication rate.First of all, according to the theory of wireless power transfer and near-fieldmagnetic communication technology, the power and efficiency in powertransmission and the power, response time and bandwidth in informationtransmission are selected as the main parameters to measure the performance oftransmission, the relationship between these parameters and the quality factor ofcircuit is analyzed.Second, by analyzing the dual-band resonant circuit, the concept ofequivalent inductance is proposed and used to calculate the bandwidth and theresponse time of dual-band resonant circuit. The concept of transfer factor isproposed and used to measure the performance of power and informationtransmission instead of quality factor. The parallel coil is more suitable ascoupling coil. In further analyzing, the change of capacitance and inductancevalues in dual-band resonant circuit, will directly affect the position of tworesonant point and the value of the transfer factor. Mutual inductance couplingmodel is used in system modeling, mathematical and circuit simulation software isused to study the influence of parameter changing in the circuit.Then, the hardware design of entire transmission system is completed. Fullbridge inverter circuit is chosen as the power source, litz wire is used to wind thecoil, binary amplitude shift keying is used as signal modulation scheme,inductively coupling is used as information injection scheme.Finally, experiment and analysis is proceeded based on the transmissionsystem.In power transfer experiment, the influence of different transmission distanceand different load to the transfer power and efficiency is studied. When the loadvalue is less than10, the transmission distance is less than120mm, above70%transfer efficiency can be realized.In information transfer experiment, the information can be injected efficiently through inductively coupling without impacting on power transfer, the separationof information and power is realized, the modulation and demodulation arerealized. The response time decides data transfer rate. When the load value is1.31, the transmission distance is122mm,56kHz data transfer rate can beachieved.