Design Of Fully Digitally Controlled Wireless Power Transmission System

Wireless power transfer(WPT)technology,It is a new type of power transmission method that realizes electric energy transmission from the power source to the load without electrical contact through electromagnetic effect or energy exchange,Compared with the traditional wired transmission method,it has the advantages of safety and reliability,suitable for special occasions,etc.At present,WPT technology has been greatly developed and has been applied to mobile phone charging,electric vehicle charging,internal medical device power supply,underwater power supply,and so on.The current wireless power transfer control system.It is mainly constructed by analog circuits.The circuits are complicated,easy to age,and have temperature drift.The center frequency cannot be changed.Given the above reasons,this dissertation studies the wireless power transmission system and designs a fully digitally controlled wireless power transmission system based on the field programmable logic gate array(FPGA).First,based on the circuit theory,a mathematical model of the two-coil,three-coil,and four-coil structures of the WPT system are established.According to the mathematical model,the transmission efficiency of the two-coil,three-coil,and fourcoil structures at different transmission distances is analyzed in detail.And use MATLAB to draw the transfer efficiency curve.After selecting the two-coil structure as the project proposal,the relationship between the two-coil structure,frequency,and transmission distance was analyzed in detail,and a dual-coil model was established in COMSOL.The dual-coil model was simulated under different frequencies.Electromagnetic field simulation.Secondly,this dissertation uses power electronics to complete the design of highfrequency switching power supplies,including the design of inverter circuits and directcurrent(DC-DC)buck-boost circuits,drive circuit and so on.The principle of WPT system detuning and frequency tracking is analyzed,and a scheme for implementing a frequency tracking control system using a phase-locked loop is determined.The main innovation of this article is to establish and analyze a mathematical model of an alldigital phase-locked loop designed based on the principle of feedback control.Through simulation analysis,it is found that the phase-locked loop’s phase-locked speed and phase-locked accuracy are different under the effect of different PI parameters.The segment parameter selection module greatly improves the phase-locking speed and phase-locking accuracy.Finally,an all-digital phase-locked loop is implemented based on the Altera EP4CE10 series FPGA.Then,based on the all-digital phase-locked loop,a phase acquisition module,an initial excitation module,a system protection module,and a dead-band processing module were designed,and a frequency tracking control system was implemented using Verilog programming.It is verified by Modelsim software simulation,which meets the expectation.Finally,the open-loop high-frequency power is combined with the frequency tracking control system to form a fully digitally controlled wireless energy transfer system.Through system experiments,it is verified that the system can work normally,and it is verified that the control system can solve the problems caused by the system’s detuning,transmission efficiency,and energy instability,and can work stably.