恒压钳位高速关断瞬变电磁发射系统

Voltage stabilized clamping and fast turn-off transient electromagnetic transmitting system

瞬变电磁发射机是瞬变电磁探测设备中的重要组成部分,在大功率电流陡脉冲发射、高精度同步控制、下降沿线性度、短关断时间和关断时间测量等方面,有许多亟待解决的问题。提出了一种瞬变电磁发射系统,DSP和FPGA协同工作为系统提供可靠的驱动信号和保护措施;提出了恒压钳位电路,配合合适的阻尼吸收电路,具有关断时间短、电流下降沿线性度高和发射电流大的特点,并可提升脉冲电流前沿上升速度;提出了新颖的关断时间测量电路,测量准确简单;设计了GPS同步控制器,采用GPS与温补晶振协同工作的方式,解决了GPS短时失效的问题,提高了系统的可靠性。对发射系统做了野外实验,测试表明,系统发射电流大、电流下降沿线性度高、关断时间测量准确、同步方式精确可靠。

Transient electromagnetic transmitter is an important part in transient electromagnetic detection equipment. In the aspects of high-power current steep pulse transmission, high precision synchronous control, falling-edge lineari- ty, short turn-off time, turn-off time measurement and etc. , there are still a lot of problems to be solved urgently. This paper proposes a novel extra fast turn-off transient electromagnetic transmitting system, DSP and FPGA are used to work together and provide the system with reliable driving signals and protective measures. The system adopts a volt- age stabilized clamping circuit and a damping resistance circuit, and has the characteristics of short turn-off time, high current falling-edge linearity and high transmission current;besides it can improve the speed of pulse current rising- edge. The system also adopts a novel turn-off time measurement circuit, which makes the measurement simple and ac- curate. A GPS synchronous controller is designed, which adopts a cooperative operation mode with a temperature com- pensated crystal, solves the GPS short-time failure problem and improves the reliability of the system. The transmitting system field experiment was carried out, experiment results show that the system features high transmission current, good current falling-edge linearity, accurate turn-off time measurement, and precise and reliable synchronous control. The system is easy to carry, convenient to operate, and has excellent performance.