| Subsea equipment needs to be powered to work underwater for long periods of time.However,in underwater environment,the traditional plugging charging mode is easy to produce corrosion and leakage.The use of underwater wireless transmission has solved this problem.However,in practical application,the low efficiency of underwater wireless power transmission and the inconvenience of information transmission in the power transmission system are the problems that need to be studied in this field.In view of the above problems,this thesis delves into the examination of both the underwater wireless power transmission system based on magnetic induction coupling and the information synchronous transmission system.The main research contents are as follows:(1)In order to improve the transmission efficiency of this system,the electromagnetic coupling mechanism is optimized.By analyzing the principle and loss of the electromagnetic coupling mechanism,and using Ansys Maxwell to carry out magnetic field simulation of the electromagnetic coupling device,to carry out eddy current field simulation of the electromagnetic coupling device working in the seawater environment,a kind of underwater electromagnetic coupling device was designed with the tank core as the main structure and the external use of epoxy resin and metal shell.The improved electromagnetic coupling device improves the transmission efficiency by about 6%.By analyzing the resonant compensation circuit,a suitable resonant compensation method is designed.The inverter circuit and rectifier circuit are designed by analyzing and comparing various kinds of rectifier circuit and inverter circuit.In order to conveniently measure the parameters of the circuit,an automatic measurement system for power transmission efficiency is designed.(2)In order to realize the transmission of power and information in the same channel and reduce the influence of information transmission on power transmission,this thesis combines the circuit characteristics of wireless power transmission system,frequency shift keying is used for downlink communication and load modulation is used for uplink communication.In the process of downlink communication design,signal modulation circuit is designed according to the frequency adjustable characteristic of resonant controller.By comparing the transmission efficiency of the power transmission system at different frequencies and selecting appropriate design parameters,a signal demodulation circuit is designed using high-pass filter circuit and voltage comparator.Uplink communication based on load modulation principle design signal modulation circuit.By analyzing the power transmission efficiency of the system under different loads,the appropriate communication load is selected.A signal demodulation circuit is designed using current sensor and voltage comparator.Finally,the two communication schemes are verified by simulation using Multisim software.(3)The system experiment platform was built to verify the wireless power transmission system and information transmission system.Experimental results show that when the wireless power transmission system designed in this paper operates in the air,the maximum transmission power reaches more than 250 W and the maximum transmission efficiency reaches about 74%.Moreover,the system has the characteristics of constant voltage output when the input is constant voltage,and has good anti-migration ability.The system also has good output performance in underwater power transmission,and the design of reducing eddy current loss in underwater operation has been effectively verified.The experiment of wireless power and information synchronous transmission system proves the feasibility of synchronous transmission of information and electric energy,verifies that the communication scheme has little influence on the efficiency of electric energy transmission,and verifies that the system can realize two-way transmission of information. |
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