Research And Implementation Of Constant Voltage Wireless Transmission System

Compare with the traditional wired power supply method,wireless power transmission(WPT)technology has better convenience and security,and can adapt to a more complex external environment.It has been widely used and developed in recent years.However,the wireless power transmission system still has the problems that the output power is not stable and the output voltage and current control is difficult.In response to the above problems,this paper proposes a set of constant voltage wireless power supply device with stable output.This paper first introduces the basic structure and working principle of the WPT system,uses circuit theory to establish the traditional compensation topology and the equivalent model of the loosely coupled transformer,and analyzes the transmission characteristics of the traditional compensation topology.By combining the LC compensation topology with the traditional S compensation topology,a new LC-S compensation topology is proposed.The compensation network can realize the transmission characteristics of constant voltage input-constant voltage output through parameter configuration.By comparing the transmission characteristics of the traditional compensation topology and the LC-S compensation topology through Pspice circuit simulation software,the influence of the changes in the working environment on the output characteristics of different compensation topologies is analyzed.Secondly,in order to enhance the transmission capacity of the system and improve the stability of the output power of the WPT system,this paper establishes the energy transmission model of the loosely coupled transformer,theoretically analyzes the transmission performance and magnetic circuit characteristics,and determines the optimal design direction of the coil.Using Maxwell simulation software to analyze the effect of coil structure parameters on the coupling capacity of loosely coupled transformers,the coil structure of WPT system was designed.In order to improve the system power density,a new magnetic core structure is proposed,which reduces the volume and weight of the loosely coupled transformer and improves the system coupling capacity.Then,according to the requirements of the system indicators,the overall design of the constant voltage wireless power supply device is formulated.Design the main circuit and peripheral hardware circuit of the system and optimize the selection of main components.Add a synchronous Buck circuit at the receiving end of the WPT system to determine the main parameters of the synchronous Buck circuit and optimize the selection of corresponding components.The PI adjustment method is used to design the closed-loop controller to realize the closed-loop control of the WPT system and maintain the stability of the system output voltage.Finally,according to the theoretical analysis and simulation experiment design and manufacture of the loosely coupled transformer,and determine the LC-S compensation network parameters,use Altium Designer to draw the circuit board,complete the development of the prototype of the constant voltage wireless power supply device.Through the frequency conversion experiment,vertical offset experiment,horizontal offset experiment and variable load experiment,the transmission characteristics of the designed constant voltage wireless power supply device prototype are analyzed.The experimental analysis results verify the correctness and reasonableness of the theoretical analysis and simulation research of this subject Sex.The designed prototype of the constant voltage wireless power supply device achieves a 280 V constant voltage output at a transmission distance of 40mm-60 mm,a maximum output power of 1k W,and a maximum transmission efficiency of 79%.