The Design Of Distributed High-frequency Magnetic Field Distributed Test System Based On High-speed Serial Bus

Magnetic resonance coupled wireless energy transmission technology is a hot topic in the field of wireless energy transmission.As a medium of energy transmission,the magnetic field directly affects the transmission efficiency of the system.The study of the spatial magnetic field distribution is an important way to solve the problems currently faced by this technology.Scholars at home and abroad have conducted a lot of research on the measurement technology of the spatial magnetic field distribution in wireless energy transmission.In order to accurately reflect the spatial magnetic field distribution in real time,this paper designs a distributed magnetic field test system based on a high-speed serial bus to achieve high-speed synchronous detection of the spatial magnetic field distribution.The thesis first carried out a detailed scheme design for the system,focusing on the overall scheme of the test system,the magnetic sensor area array scheme,the high-speed bus scheme,the servo system scheme and the host computer monitoring system scheme.Among them,a method for automatic calibration of variable damping resonance network is proposed for magnetic sensors to achieve precise measurement of space high-frequency magnetic fields.According to the system plan,the specific software and hardware implementation of each functional unit is carried out.In terms of system hardware,the paper details the schematic design,chip selection and PCB design of some typical functional modules.It mainly includes conditioning module composed of resonant network,impedance matching,peak detection,program-controlled amplification,and sample and hold;digital module composed of STM32 and DAC;acquisition and communication module composed of FPGA,ADC and MLVDS;The main node module composed of SATA interface and hard disk;and the servo system module composed of STC8A8 K and wireless module.In terms of system software,the system communication protocol,the control mechanism of the single chip microcomputer based on time slice polling,the control mechanism of the high-speed synchronous bus based on time division multiple access,the DDR2 "ping pong" cache mechanism,the design of hardware file management based on FAT32,based on The software design of the host computer of Lab VIEW and the program realization method of each typical functional unit based on the state machine.On the basis of hardware and software design,the thesis describes the debugging process of typical functional units in detail,as well as the problems and solutions in the simulation debugging process.For FPGA debugging,the bus simulation timing waveform diagram based on Model Sim is given.Aiming at the hardware circuit debugging,the waveforms of the debugging process of key circuits such as amplifier circuit,sample-and-hold circuit and sensor calibration circuit are given.Finally,a system test was carried out on a 5-meter-long mobile measurement and control platform.36 magnetic sensors form a sensor area array.The area array has two sets of master nodes.Each group of master nodes mounts six busses and the communication rate of each high-speed bus Reaching 144Mbit/s,the master node will "ping pong" the cache operation of the data through DDR2,and then store the data to the hard disk through the SATA interface at a transmission rate of 1200Mbit/s,realizing the high-speed storage function of the data.The experimental results show that the distributed high-frequency magnetic field test system can achieve distributed acquisition of the high-frequency magnetic field in space.With the hard disk as the data storage carrier,the host computer can monitor the system and achieve the design goal.