A Magnetic Induction Detection System With Counter Magnetic Field Excitation Coil

In the traditional magnetic induction detection technology,the excitation magnetic field at the receiving coil position often seriously affects the detection of the detected object signal.In the magnetic induction topology with counter magnetic field excitation coil,the excitation magnetic field does not interfere with the receiving coil.This paper designs a hardware system based on this structure and validates it experimentally.First,this paper introduces the basic principle of magnetic induction detection technology,and analyzes the theory applied in the process of engineering magnetic induction detection system.Based on these theories,the basic parameters of the system were calculated using the finite element analysis software COMSOL,and the measured signals of the system when the measured object was copper and salt water were also simulated.Then,based on theoretical analysis and simulation results,an actual hardware experiment system was built,and the sensitivity and SNR of the detection system were improved as much as possible.In the experimental stage,aiming at the problem that the receiving coil voltage is not zero when there is no object to be measured,a high-precision zero adjustment scheme is designed to solve the problem that the system is severely disturbed and that the state is unstable in practical application.Finally,different concentrations of saline were tested using the designed hardware system and experimental protocol.Simulation and experimental results show that the magnetic induction detection system not only has high sensitivity,but also has a strong adaptability to complex and varied electromagnetic environment.