Design Of Magnetic Resonant Coupling Wireless Power Transmission System Against The Seawater Flow Vibration

Autonomous Underwater Vehicle(AUV)has become an important tool for humans to explore the ocean for its advantages of wide range of motivations,good flexibility and intelligent operation.By using magnetic resonant coupling wireless power transmission technology to complete the wireless charging of AUV,the efficiency and concealment of AUV are improved.In the sea,eddy current loss caused by the conductivity of seawater reduces the transmission efficiency.The seawater flow vibration causes the roll and relative axial offset between the AUV and the base station,which results in the changing of eccentricity and mutual inductance of the coupling coil and affects the stability of power transmission.In view of the key technical problems to be solved in the marine environment,the major researches are as follows:1.A three-coil wireless power transmission structure,of which the two transmitting coils are at the same size as the receiving coils and are placed symmetrically on each side of the receiving coil,is proposed to reduce the eddy current loss of sea water.The analytical expressions of electric fields of three-coil system are established,and a calculation method of the eddy current loss equivalent impedance is established as well.It is concluded that the threecoil system can decrease eddy current loss.2.Aiming at reduce the influence of the seawater flow vibration on the wireless power transmission performance of AUV in the seawater environment,a concentric helical three-coil structure is presented.The recycling cage of the base station is installed with two transmitting coils,the diameter of which is larger than the receiving coil.The receiving coils are fixed on the AUV,and the axes of the three coils are in line with the AUV axis.Besides,a discrete calculation model of synthetic electric field is established.The correctness of the discrete calculation method of the synthetic electric field is been validated in this thesis,and the concentric helical three-coil system is proved to have the ability to against Z-axial disturbance.3.For the three-coil system,the compensated circuit topology is studied.We analyze the shared compensated capacitance topology,the separately compensated capacitance topology and the series compensated capacitance topology when two transmitting coils in series.The simulation and experimental results show that the transmission efficiency of three-coil structure can be increased by about 10% when the three-coil structure and the traditional two-coil structure transmitting the same power in the marine environment,and the shared compensation capacitor topology has stronger robustness for mutual inductance changes.The results show that the three-coil wireless power transmission system can reduce eddy current losses and has a strong ability to resist the seawater flow vibration.Thus,it has a good application prospect in marine environment.