Research On Key Technology Of Nuclear Magnetic Resonance Water Detector Transmitter

Freshwater resources are one of the most scarce resources at present,and the effective detection and exploitation of groundwater is of great significance.At present,there are many kinds of geophysical methods used to find groundwater.These methods can only detect the differences in physical properties,and they are not unique to the interpretation of the inversion results.Therefore,multiple methods are often required for joint interpretation.The NMR water search method is a physical detection method that directly addresses water.It can not only determine whether there is groundwater,but also has the technical advantage of where there is water and how much water.Therefore,it is of great significance to carry out research on the key technologies of nuclear magnetic resonance water search instrument..In this paper,starting from the principle of NMR water-retrieving water detector,based on the analysis of the principle of NMR water-seeking process and the introduction of the system of NMR water-receiving water detector,a NMR water-receiving-flow-meter transmitter structure is proposed and launched.The following key technologies have been studied in the process of energy loss during machine charging and output power attenuation during discharge:1)When the transmitter is working,it needs to instantaneously output a large-voltage,high-current power pulse signal output.This can be used to supply high-voltage and large-capacity capacitor banks to achieve instantaneous high-power electrical energy output,through comparison of different RC parameters and analysis.The attenuation characteristics of the output power of the transmitter are optimized for the RC parameters without affecting the performance of the transmitter.2)For the charging process of the storage capacitor in the 0-200 V charging process,there is a problem of large energy loss in the constant current source charging mode.A closed-loop charging system is designed.The system controls the voltage value on the MOS tube to make It is kept constant during the charging process to reduce the energy loss during the charging process and to extend the working time of the mobile power source in the field.3)For the problem that the output energy of the energy storage capacitor is rapidly attenuated during the excitation process of the transmitter,a dynamic energy compensation system with a closed-loop structure is designed to control the dynamics of the controllable constant current source while the transmitter outputs electrical energy to the coil.The output current is adjusted,and the energy stored in the storage capacitor is synchronously compensated to achieve the purpose of keeping the output power of the capacitor constant during the transmission process of the transmitter,so as to guarantee the quality of the transmitter waveform and shorten the effective emission time of the transmitter,and eventually improve the The efficiency of the instrument.Based on the study of the above key technologies,the various circuit modules of the transmitter were designed and related experiments were carried out to verify the feasibility of the design of a high-efficiency power supply system and the design of a compensation charging system,and to solve the energy of the transmitter energy storage capacitor during charging.The problem of large loss,the problem of output power attenuation during the discharge of the energy storage capacitor,reduces the energy loss when the capacitor is charged,prolongs the use time of the power supply in the field,and improves the working efficiency of the instrument.