Research On Electromagnetic Wave Field Source Emission System With Pseudo Random Coding

Electromagnetic detection method is a commonly used method in geophysical prospecting.According to the different resistivity parameters of the conductive media in the stratum,the geophysical conditions of the unknown stratum can be investigated quickly and efficiently.With the advancement of actual exploration work,controllable electromagnetic sources have become an important means to solve unconventional oil and gas reservoirs or minerals.Stray magnetic interference is strong in the field construction site,which will produce large errors and affect the accuracy of the detection results.Pseudo-random codes have white noise properties and good autocorrelation,so they have a good anti-noise effect and can effectively improve the signal-to-noise ratio.This article is based on this kind of thinking from the perspective of the code source,and applies the pseudo-random code to the geophysical detection direction.In this paper,the research of pseudo-random coded electromagnetic wave field source emission system is carried out.The main research content and innovation are embodied in the following aspects:(1)Based on the investigation and research of the practicality of field exploration,this paper proposes an electromagnetic field source emission system with multiple combined functions.By equipping the transmitter system with the functions of a pseudo-random constant current step source and a pseudo-random pulse source at the same time,it not only effectively improves the anti-interference ability,but also enhances the ease of use of the system,and further improves the efficiency of exploration work.(2)Based on the research of push-pull quasi-resonant conversion principle,a portable power supply without heat dissipation link is designed.A portable power supply can complete the power supply requirements of the entire system,and supply power to each part through the isolation circuit link without affecting each other.In addition,the power supply is completed by a DC boost push-pull circuit,there is no uncontrollable rectification link,less reactive power,high energy utilization,and less heat loss,so the heat dissipation link is eliminated,and the volume is lighter and smaller.(3)Based on the understanding and mastery of the transmitter circuit principle,a hardware circuit design with IPM(Intelligent Power Module)as the main body is carried out.Because IPM has a high degree of integration,the volume of the main power link is also very small.In view of the consideration of PID,the main power design circuit is designed to include undervoltage,overvoltage,overcurrent,temperature,snubber circuit and other protection circuits,and specific calculations are made for the selection of related parameters to improve the safety of the system And stability.(4)Combined with the idea of pulse width modulation technology,the duty cycle of H bridge pulse width is adjusted through software and hardware conditions to realize constant current feedback control.The effective duty ratio of the electronic switch is adjusted by the pulse width modulation method,and then the output voltage is controlled to achieve the purpose of controlling the current.Another significant advantage of the pulse width modulation method is that it can increase the service life of the electronic switch.The outdoor test proves that the electromagnetic wave field source emission system designed in this paper meets the design requirements and has greater practical application value.Considering the actual design process and test results,there are still areas that can be further improved,and it can be further developed due to its greater requirements for engineering exploration and use.