基于SiC MOSFET的浅层高分辨瞬变电磁发射机研制  

Development of transient electromagnetic transmitter based on SiC MOSFET for high-resolution near-surface

作　　者：淳少恒 王飞飞[2,3] 陈儒军 申瑞杰[2,3] 彭鑫[2,3] 许超 殷昊[2,3] CHUN ShaoHeng;WANG FeiFei;CHEN RuJun;SHEN RuiJie;PENG Xin;XU Chao;YIN Hao(Wuxi Institute of Technology,Wuxi 214121,China;School of Geosciences and Info-Physics,Central South University,Changsha 410083,China;AIoT Innovation and Entrepreneurship Education Center for Geology and Geophysics,Central South University,Changsha 410083,China)

机构地区：[1]无锡职业技术学院,无锡214121 [2]中南大学地球科学与信息物理学院,长沙410083 [3]中南大学AIoT(人工智能物联网)与地质地球物理创新创业教育中心,长沙410083

出　　处：《地球物理学进展》2025年第1期358-371,共14页Progress in Geophysics

基　　金：国家重点研发计划(2022YFF0706201);校级博士科研课题基金项目(10492722007);校级自然科学类科研创新团队(ZKTD202403);“太湖之光”科技攻关(基础研究)(K20241058);江苏省高等学校基础科学(自然科学)研究面上项目(22KJB510044);江苏省“双创博士”计划(JSSCBS20221066);江苏省高等学校基础科学(自然科学)研究重大项目(23KJA510010);江苏省高校科技创新团队项目联合资助。

摘　　要：瞬变电磁发射机作为瞬变电磁法勘探的重要组成部分,它的性能几乎就决定了该方法勘探的有效性.为对浅层甚至是甚浅层采用多匝小线圈进行精确勘探,本文基于SiC MOSFET器件设计一种改进型的瞬变电磁发射机.SiC MOSFET是第三代半导体,相比目前被广泛应用的Si IGBT,该器件在耐压、耐流、散热和响应速度方面均有显著提升.关断时间作为发射机的一项重要参数,基本决定了一次场与二次场信号的耦合程度.为不丢失甚浅层和较浅层信息,本文设计的发射机支持大小两种电流切换发射.当对甚浅层或较浅层区域进行勘探时,可选择1.1 A小电流发射,关断时间只有4μs.当对浅层区域进行勘探时,可选择16.2 A大电流发射,关断时间为35μs.为给后期处理提供发射电流数据支撑,本文设计了支持变采样率的电流采集系统来对发射波形进行全时域采集.当处于发射波形上升沿或下降沿附近区域时,采集系统自动选择1.8 MSPS高采样率进行采样,当处于发射波形稳态区域时,采集系统自动选择50 KSPS最低采样率进行采样.测试表明,通过变采样率采样,能有效平衡采集精度和数据量,从而保证了存储系统的稳定性.此外,本发射机电路板尺寸较小,只有255 mm×192 mm,并且支持12 V蓄电瓶供电,所以便携性较好,能一定程度上提高野外勘探效率.As an important component of Transient Electromagnetic(TEM)prospecting,the performance of a TEM transmitter almost determines the effectiveness of this prospecting method.In order to accurately prospect shallow and even very shallow layers using multi-turn small coils,this paper designs an improved TEM transmitter based on SiC MOSFET.SiC MOSFET is a third-generation semiconductor that offers significant improvements in voltage withstanding,current withstanding,heat dissipation,and response speed compared to widely used Si IGBT.The shut-off time,as a critical parameter of the transmitter,essentially determines the degree of coupling between the primary and secondary field signals.To prevent losing information in even very shallow and relatively shallow layers,the transmitter designed in this paper supports switching transmission between large and small currents.When prospecting in even very shallow or relatively shallow layers,a small current of 1.1 A can be selected,with a shut-off time of only 4μs.When prospecting in shallow layers,a large current of 16.2 A can be selected,with a shut-off time of 35μs.To provide transmitting current data use for post-processing,this paper designs a current acquisition system that supports dynamic sampling rate to collect the current waveform in the whole time.When the current waveform is in the rising or falling edge area,the acquisition system automatically selects a high sampling rate of 1.8 MSPS for sampling.When the current waveform is in the steady-state area,the acquisition system automatically selects the lowest sampling rate of 50 KSPS for sampling.Tests show that by sampling with dynamic sampling rate,the acquisition accuracy and data volume can be effectively balanced,thereby ensuring the stability of the storage system.In addition,the transmitter board has a small size of only 255 mm×192 mm,and supports 12 V battery power supply,so it has good portability and can improve field prospecting efficiency to a certain extent.

关 键 词：关断时间 SiC MOSFET 无源恒压钳位 大小电流切换发射 变采样率 

分 类 号：P631[天文地球—地质矿产勘探]