A Design Of Underwater Contactless Inductive Power Transfer System With Data Transmission

Together with the rapid development of power electronics technology,the Contactless Power Transfer(CPT)technology is also stepping forward.For the flexibility and high efficiency,the CPT technology is widely used in many fields,such as implantable devices,electrical vehicles and underwater charging.CPT technology is able to deal with the port abrasion,corrosion and electric leakage problems occurred in conventional underwater charging devices.Thus CPT is a promising technology,especially in underwater charging field.Moreover,with more and more communication requirement while devices are in charged,a number of researches focus on the fusion of CPT and communication technology.A typical structure of CPT technology is call Inductive Power Transfer(IPT),which realizes power transfer via coupled coils.The power can be transferred while the source and load are isolated.The convention implementation of IPT system is dual resonance structure.The coupled coils are compensated by capacitors that the whole system is resonant when working at the designed frequency.Dual resonance structure achieves satisfying efficiency but is sensitive to the loads.Additionally,the efficiency changes a lot when frequency splitting is occurred in coupled coils.Once communication module is attached,the output will be affected.In order to solve those problems mentioned above,this thesis mainly focuses on these three parts.Firstly,four different compensation structures are analyzed.The output voltage gain and transfer efficiency of different compensation are derived,with which a design with load independent voltage gain and efficiency is proposed.The transfer efficiency of proposed IPT design is stable even if frequency splitting is occurred.Then simulation and experiment are carried out to verify the proposed IPT design.Secondly,base on the proposed IPT system,a design of underwater contactless power and data transfer system is proposed.The relation among structure,transmission media and parameters are analyzed.According to the analysis and simulation,an equivalent model of coupled coils underwater is established.A experiment is also carried out to verify the simulation and find out the difference of efficiency between air and seawater.Finally,a novel communication module design used in IPT system is proposed,which is able to realize power transfer and data transmission in the meantime.The proposed communication module design not only keeps the output characteristics of IPT system unchanged but also alleviates the interruption between power and data signals.Then a simulation model is established and the performance of this system is verified by simulation results.