The Design Of Downhole Wireless Power Transmission System

In the process of oilfield development,it is necessary to monitor the oil reservoir by means of all kinds of instruments and meters resided down-hole,which can provide scientific basis for the dynamic analysis and oil developmental.These instruments and meters are usually supplied with contact power in a traditional way,and this kind of power supply has many disadvantages for the oil well.As a new way of electrical power transmission,wireless power transmission has incomparable advantages compared with traditional power transmission.Therefore,it is of great significance to develop a reliable system of downhole power transmission.To solve the problem of the application of wireless power transmission in the down-hole,this paper studies the related data of wireless power transmission,introduces the development situation of wireless power transmission at home and abroad,as well as its application in the down-hole,analyzes and compares the advantages and disadvantages of three kinds of wireless power transmission systems,such as radiation,electromagnetic induction and resonant coupling,finally according to the practical situation of the downhole application,the magnetic coupling resonant power transmission mode is selected as the choice of the scheme.then the basic principle of the magnetic coupled resonance wireless power transmission are introduced and the scheme of the system is proposed,and the components of the system,such as the circuit of PWM signal generation and inverter and driving and receiver,are described and demonstrated.Especially,The influence of the downhole environment on the power transmission system is analyzed,and the relevant electromagnetic coupler is designed to reduce that effect.It analyzes the detuning of wireless power transmission system in open loop,puts forward the scheme of frequency tracking system based on FPGA,Finally,the circuit is built and the experimental results show that the system achieve the function of wireless power coupling,the efficiency of transmission of the frequency tracking system is 14% higher then that of the open loop wireless power transmission system at the distance of 3cm.The results provide a foundation for the future.