基于恒流源的矿用隔爆兼本安型瞬变电磁发射机研制

Development of mine flame-proof and intrinsically safe transient electromagnetic transmitter based on constant current power supply

由于瞬变电磁技术对水体反应灵敏,已被应用于煤矿井下水害探测。为提高探测精度,研究了恒流发射技术,采用脉冲宽度调制与功率场效应管结合,保证发射电流在探测过程中保持恒定;为提高二次场强度,采用了电感反向截断技术,利用电感中电流突然关断产生反向高压原理,缩短电流关断时间;通过外部中断与微控制器内部定时器配合,记录发射电流关断时间;采用隔爆兼本安型结构设计,保证仪器在井下安全使用。最后通过实验室测试和充水巷道探测,验证了仪器的准确性和有效性。

Because of the good sensitivity to water, transient electromagnetic technique is used for mine water disaster detection. In order to improve the detection accuracy, constant current emission technology is studied. The pulse width modulation technique and power MOSFET are combined to ensure the transmitting current keeping constant during the detection process. In order to improve the intensity of secondary field, the inductance inverse-break technique is adopted. The principle is adopted that high inverse voltage is generated on the inductance when the current in the inductance is turned off suddenly, which shortens the turn-off time of transmitting current. The turn-off time of transmitting current is recorded through combining the peripheral interrupt and internal timer in the microcontroller. The flame-proof and intrinsically safe structure design is adopted, which insures the safe operation of the instrument under coal mine. Finally, laboratory test and the detection experiment in water - filled tunnel were conducted, the results verify the accuraey and effectiveness of the instrument.