An Electromagnetic Feedback Method to Improve Low-Frequency Response Performance of Geophone

In order to prospect deep geological structure, low natural frequency geophone is needed. Traditionally, low natural frequency (less than 10Hz) of geophone is acquired by increasing its volume of coil or magnetic body. But that makes it too heavy to be widely used in oil seismic exploration. This manuscript introduces a new method to broaden the low frequency of geophone without changing its structure. A new electromagnetic force feedback network generated by genetic algorithms (GA) is attached to the two output poles of moving-coil geophone, whose performance of low-frequency response is thus improved. Through PSPICE simulation and the real vibration test of moving-coil geophone, we get a more accurate model of geophone. With these models, GA is used to optimize a new structure of feedback network and the parameters for broadening geophone's low frequency response. Test results have proved the validity of our methods.