Research On Three-dimensional Wireless Power Supply Technology With Cavity Resonance

In this article,it’s aimed to provide flexible power supply for portable devices that move freely in three-dimensional space and explore the application of cavity resonance in wireless power supply technology.The transmission methods of wireless power transfer(WPT)technology that are currently widely used are highly directional and lacking flexibility,which are not suitable for flexibly powering devices in a three-dimensional space.Quasi-Static Cavity Resonator(QSCR)uses cavity resonance to excite a three-dimensional electromagnetic field to transmit energy.Portable devices in the cavity can flexibly receive power while moving and working.Therefore,QSCR is selected as the research target in this paper,and its characteristics are explored from the perspective of theory,simulation,and experiment.The element radiator model is used to analyze the field distribution of QSCR,and the field distribution of QSCR is also analyzed through the structural similarity between QSCR and resonant cavity.According to the total power conservation of system,the system transmission efficiency is derived from the perspective of energy dissipation and the influencing factors are analyzed.At the same time,actual parameters are used to verify the derived system transmission efficiency.The derivation results show that transmission efficiency is related to the surface material of QSCR,size of receiving coil,and position of receiving coil.The maximum transmission efficiency of system is calculated by using actual parameters to be 48%.To carry out experimental research on cavity resonance wireless power supply technology,a QSCR and receiving mechanism are designed and manufactured.The receiving mechanism includes a planar spiral coil made of Litz wire used for the system characteristic experiment and a PCB coil used for wireless power supply experiment.The influence of the resonance capacitance in the cavity resonance wireless power supply system on the operating frequency of system and the influence of the distance from receiving coil to electrode,height from the ground,rotation angle,and revolution angle are analyzed by means of simulation and experiment.The experimental results show that the distance between receiving coil and electrode as well as rotation have a greater influence on transmission efficiency,while the ground clearance and revolution angle have a relatively small influence on transmission efficiency.In addition,through simulation and comparison of the magnetic field generated by QSCR and the transmitting coil of magnetic coupling WPT,the internal magnetic field of QSCR is more stable than magnetic coupling WPT technology,so QSCR is suitable for a wide range of flexible power supply.A high-frequency inverter power supply suitable for cavity resonance wireless power supply system and a portable voltage and current wireless measurement module are designed and fabricated.With the coupling mechanism,high-frequency power supply and measurement module,wireless power supply experiments are carried out.During the experiments,current excitation is used directly instead of wave excitation to provide energy for QSCR.A smart phone,a lamp bead,and a handheld fan are selected as loads.The experimental results show that QSCR can flexibly supply power to portable devices that move freely inside.The efficiency of the wireless power supply experiment of the smartphone is 31.25%,the efficiency of the space lighting experiment is 23.07%,and the efficiency of the hand-held fan is 14.28%.Cavity resonance technology,as an emerging wireless power transmission technology,has very superior power supply flexibility.Portable devices can be charged while moving inside QSCR.The theoretical research and experiments in this paper reveal the great potential of cavity resonance technology in the direction of wireless power supply in three-dimensional space.