【作者】 付志红；

【导师】 周雒维；

【作者基本信息】 重庆大学 ， 电气工程， 2007， 博士

【摘要】 在电磁探测中,发射波形的质量直接影响到检测信号的质量和数据处理,瞬变电磁发射技术的落后,制约了我国瞬变电磁的发展。论文结合国家自然科学基金项目“基于标准场源的浅层瞬变电磁法研究”,研究电磁探测领域的电磁发射技术。论文分析了瞬变电磁发射参数对电磁响应的影响,提出缩短脉冲上升时间,减小波形畸变,提高工作效率;分析了几种后沿效应校正算法,认为大电流、短关断延时、线性下降的双极性电流陡脉冲是瞬变电磁发射技术的发展趋势。首次系统分析了国内外电磁发射技术的发展现状、存在问题和发展趋势,RCD吸收电路、线性区工作模式、阻尼电阻电路、形成线技术、PCB深孔电镀电源、IEDD电路普遍存在关断延时长、下降沿线性度差、关断特性与电源相关等缺点。针对关断延时问题,提出了准谐振、恒压钳位及串联型多种电路拓扑,讨论了高速关断电路的分类。根据适用于不同的功率应用,分为小功率、中功率、大功率、超浅层几类;根据工作原理的不同,分为阻尼电阻、准谐振、恒压钳位、串联型等几类。研究了各种电路拓扑输出特性、参数计算和适用条件。提出了准谐振型高速关断电路,建立了电路参数优化模型。该电路关断延时大大缩短,电流无过冲,下降沿一致性好,晚期线性度较好;馈能型电路减小了能量损耗,具有前沿提升能力;耗能型电路具有更小的关断延时,更好的线性度,且与供电电压、发射电流无关。提出了恒压钳位高速关断思想,提出了它的三种形式:耗能型、馈能型和无损型电路。提出电路下降沿线性度高,可实现下降沿斜率可调;与已报道电路和准谐振型电路相比,关断延时最短;馈能型电路对前沿有提升作用;电路参数最优解不随电源、负载、脉冲电流幅值变化,解决了国内外许多发射机需实时改变阻尼电阻以实现最佳匹配的问题。无损恒压钳位高速关断电路适应于大功率应用,是理想的TEM脉冲电流源。提出了总开关型、TVS型、Sidac-R型、串联型(RC、TVS、Sidac-R)和IGBT-MOSFET混合型几种电路拓扑,研究了阻断二极管位置对关断特性的影响。针对小功率应用,提出了基于MOSFET的TVS型最优拓扑;针对中功率应用,提出了Sidac-R阵列型时变电阻的实现算法,解决了TVS型安全性问题;针对超浅层应用,提出串联型拓扑,进一步缩短关断延时。提出了前沿恒压钳位的思想,提升恒流源电路和恒流调制策略,实现了电流脉冲前沿的线性、高陡度提升和输出电流的恒流。“前沿”线性提升电路、输出恒流控制和恒压钳位电路实现了有机的结合,实现了精确的高陡度梯形波脉冲。采用恒压钳位高速关断技术,研制成功10kW大功率瞬变电磁发射机。关断延时指标超过国外先进仪器水平,下降沿线性度高,电路参数最优解不随电源、负载、脉冲电流幅值变化。研制成功的大功率发射机已经批量生产,性能稳定,效果良好。目前,电磁发射技术的报道在国内外还非常鲜见,作者首次系统地研究了地质勘查中的电磁发射理论,对于促进我国电磁探测技术的发展,具有重要的理论意义和实用价值。部分成果实现了转化,产生了良好的经济效益和社会效益。更多还原

【Abstract】 In electromagnetic detecting, the quality of the transmitting waveform directly influences data quality and data processing. However, in a long period, the undeveloped status in electromagnetic transmitting technology restricts the development of transient electromagnetic applications in China. Focused on the electromagnetic transmitting technology in electromagnetic prospecting field, the thesis studies the electromagnetic detecting transmitting technology, which is supported by National Natural Science Foundation of China (50577071)"research on the superficial transient electromagnetic method based on standard field source".The thesis analyzes the effect on TEM response by transmitting parameters, and cognizes that cutting short the rising time can minish the waveform aberration, and improve the work efficiency. By analyzing several kind of fall-edge effect amending arithmetic, the thesis concludes that the bi-polarity current pulse with high current, short turn-off time, and linear fall-edge is the technical trend of transient electromagnetic transmitting.The thesis comprehensively analyzes the present status, problems and trend of electromagnetic transmitting technology, concludes much shortcomings of many transmitting circuits, such as RCD snubber, linearity area work mode, damping resistance circuit, pulse forming lines, PCB deep-hole electroplating power supply, IEDD circuit, etc. which have long turn-off delay time, bad linearity, and related the power supply etc.A novel quasi-resonant current steep pulse transmitting circuits is presented with a device parameters optimizing models. It is concluded that the proposed circuits have less turn-off delay time, eliminating the current over-shot and improving the turn-off consistency, having better linearity. Besides, the energy-feedback circuit can accelerate the ascending of current, cut down the energy loss. Compared to energy-feedback circuit, the energy-dissipation circuit has less turn-off time, better linearity. And, its turn-off delay is incorrelative to transmitting current and supply voltage.A stabilizing voltage clamping high-speed turn-off technique is put forward based on its three forms comprehensively, the energy-dissipation, energy-feedback and lossless stabilizing voltage clamping high-speed turn-off circuit. The proposed circuits product better falling edge performance, shorter turn-off delay, higher falling edge linearity than those reported before. The energy-feedback circuit upgrades the rising-edge and decreases the energy consumption. Furthermore, the feature is independent of load inductance and transmitting current, which resolves the problem of damping resistor optimal matching, which is with domestic and foreign transmitters. The new lossless high-speed turn-off circuit is suitable to reduce the transmitter bulk. In short, lossless stabilizing voltage clamping high-speed turn-off circuit is a ideal TEM pulse current source.The author proposed main-switch, TVS, Sidac-R, RC series, TVS series, IGBT-MOSFET mixture circuit topologies, and analyze the effect on output characteristic in different interdiction diode sites. Aiming at low, middle-level power application and superficial detecting, a TVS based on MOSFET superior topology, a Sidac-R array circuit and time-varying resistor implement arithmetic, and series topologies are proposed correspondingly.A rising-edge stabilizing voltage clamping idea, a rising-edge enhancing stabilizing current source, a phase-shifting controlling strategy and a stabilizing current modulating strategy are proposed, by which current pulse implements linear, high slope rising and stabilizing current. Combined by the rising-edge linear enhancing circuit, output current stabilizing controlling, and stabilizing voltage clamping circuit adequately, a high precision, high slope trapezium pulse current source is designed.Adopted the stabilizing voltage clamping fast turn-off technique, a 10 kW high-power transient electromagnetic transmitter is designed successfully. It is showed that the key parameters such as turn-off delay time, etc., exceeds foreign advanced instrument with higher falling edge linearity and independent of load inductance and transmitting current. The high-power transmitter have been put into production in bulk, which show steady performance, superior quality.Currently, reports about electromagnetic transmitting technologies are still sparse. The author firstly studys the electromagnetic transmitting theory of geological survey field, which is important theoretical and practical values to promote the development of electromagnetic detecting technologies. The research results has partly been producted industrially with good economic and social benefits.更多还原