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1、I分 类 号：TH763 单位代码：10183研究生学号：2009552053 密 级：公 开吉林大学硕士学位论文串联谐振式航空电磁法发射机关键技术研究Research on Key Technology ofSerial-Resonant Airborne Electromagnetic Method Transmitter 作者姓名：赵阅群专业：电力电子与电力传动研究方向：功率源技术及其应用指导教师：于生宝培养单位：仪器科学与电气工程学院2012 年 6 月II串联谐振式航空电磁法发射机关键技术研究Research on Key Technology ofSerial-Resonant A
2、irborne Electromagnetic Method Transmitter 作者姓名：赵阅群专业名称：电力电子与电力传动指导教师：于生宝学位类别：工学硕士答辩日期：2012 年 6 月 1 日III摘 要直升机航空电磁法（Airborne Electromagnetic Method）地球物理勘察仪器具有快速、灵活、高效的突出优点，并且能在地形复杂环境执行地质勘察任务。国外已研制成功直升机航空瞬变电磁勘察系统，并取得了一系列研究成果，而我国在这一方向的研究还处于空白阶段。直升机航空瞬变电磁系统由发射系统和接收系统组成，本文主要研究半正弦发射电流的串联谐振式航空电磁法发射机的关键技术。
3、发射机由功率发射单元、主控单元、峰值电流采集记录单元和过冲削弱单元构成。最终通过互感器分析测试发射线圈电流波形，主要指标为 25Hz 正弦半波电流峰值达到 2725A，脉宽 4.1ms，基本满足课题要求。主要做了以下几个方面的工作：针对课题要求的发射电流指标参数，提出了串联谐振方式的功率发射电路方案，分析了该方案的工作过程和原理，并应用Matlab仿真模块Simulink对功率发射电路进行了仿真实验，取得了良好的效果。通过对功率器件工作条件分析，选取了Y45KPE型号的大功率晶闸管的作为功率开关器件；根据计算所得电感数值，设计确定了发射线圈选材、直径、圈数等参数，最终完成整个发射线圈的组装。主
4、控单元采用51单片机最小系统为核心，配合外围按键电路和液晶显示电路，实现时序信号的产生、调节和显示。大功率晶闸管驱动的设计采用分立元件搭建，主要实现对时序信号的电流放大以及通过脉冲变压器隔离强弱电之间的电联系，最后给出了控制驱动单元的PCB板实物照片和输出驱动信号波形。针对飞行过程中无法直接观测发射机发射电流的变化情况，设计了电流采集记录单元。该单元首先经过峰值检测电路将电流互感器输出模拟信号转换为直流电平信号。控制部分硬件采用51单片机最小系统为核心，外围有时钟芯片、AD转换芯片、EEPROM存储芯片、液晶显示模块，并应用模块化编程方法完成对突变电流模拟信号和时间点的采集、AD转换、记录、存
5、储和事后显示的功能。针对发射电流过冲对接收系统的不良影响，设计了电流过冲削弱单元。该单元主要利用单稳态触发芯片延时主控单元的控制信号，控制双向可控硅在发射电流将要过零的时刻将功率电阻并联于发射线圈两端达到削弱电流过冲的目IV的。而后设计了整个弱电系统的机箱面板，弱电系统的整合装箱，给出了面板设计图和机箱实物照片。叙述了组装发射机的过程以及期间应该注意的问题，而后进行了室内实验。通过示波器观测互感器输出波形，分析发射电流的大小、波形以及脉宽等参数，25Hz正弦半波、脉宽4.1ms、峰值电流2725A达到了课题要求的指标。测量过冲削弱单元功率电阻两端的电压波形，经过分析得到过冲削弱单元对发射电流过
6、冲的削弱能力达到了79.7%。关键词：航空电磁法，串联谐振，发射机，功率电子，单片机VAbstractHelicopter airborne electromagnetic method (Airborne Electromagnetic Method) geophysical survey system has outstanding advantages of fast, flexible, efficient , and takes geological survey tasks in complex terrain environment. Foreign countries have
7、 successful developed helicopter airborne electromagnetic method survey system and made a series of research results, while Chinas research in this direction is still in the blank. Helicopter airborne electromagnetic method system consists of transmitter and the receiver system. In this paper, the k
8、ey technologies ofhalf sine emission current of the series resonant AEM transmitter is researched, it includes power transmission unit, main control unit, peak current collection records unit, and overshoot weaken unit. Finally it got the indicator of 25Hz sine half-wave, peak current up to 2725A an
9、d pulse wide 4.1ms from the analysis of testing transmitter coil current waveform. Mainly the following aspects:For the index parameters of the subject requirements of the emission current, puts forward the plan of series-resonant power transmitting circuit, analyzes the process and principle of thi
10、s plan. The power transmitting circuit is simulated by using the Matlab simulation module Simlink, and achieves good result. Y45KPE models of high-power thyristors is selected as the power switching device through the working conditions of the power devices. The parameters of the transmit coil selec
11、tion, diameter, number of turns are designed by calculating inductance value, and completes the whole transmit coil. 51 SCM is used as the core of the main control unit and matching with a key circuit and liquid crystal circuitgenerates a timing signal, implementation, regulation and display.The big
12、 power thyristor drive is builtby using discrete components, its main achievement is the amplification of timing signal current and throughthe pulse transformer isolates connection between weak electric and power electrical, finally gives the control drive unit real PCB board and output drive signal
13、 waveform.The peak current collecting and recording unit is designed for the flight cannot directly observed transmitter emission peak current changes. The units analog signal VIfrom the current transformer output first passes through the peak detector circuit and is converted to DC level signal.The
14、 unit uses 51 SCM as the core, with clock chip AD conversion chip, EEPROM memory chip, liquid crystal display module, completing the mutant current signal and the time point of acquisition, AD conversion, records andstorage, and after display function. Current overshoot diminished unit is designed f
15、or the emission current overshoot adverse effect on the receiving system. The unit mainly use the chip of monostable trigger delays the main control unit timing signal to control the bidirectional thyristor in the emission current will be zero moment of power resistors in parallel at both ends of th
16、e transmitter coil to weaken the current overshoot.And then the weak current system the case panel is designed, weak systems integration is packed, and gives the panel design and cabinet photo.Narrative the transmitters assembly process and some problems which should be pay attention to during the process. And then uses the oscilloscope to observe transform
