Research On Metal Detector Sensor Based On Closed Rectangular Coil System

In order to satisfy the growing material needs of today's society,intelligent production technology has been widely used.On the production line,if raw materials are mixed with metal impurities,it will not only damage the production machines,reduce production efficiency,but also lead to accidents,which will cause unnecessary trouble to manufacturers.Using a high sensitivity and efficient metal detector on the production line can effectively solve this problem.Eddy current sensor is a non-destructive and non-contact detection instrument widely used in industrial production and scientific research.Aiming at the design of metal detector based on closed rectangular coil system is lack of detailed theoretical analysis,In view of the lack of detailed theoretical support for the design of metal detector,based on the basic theory of electromagnetic field and the differential reception theory of balance coil,the closed rectangular balance coil system sensor is systematically analyzed and optimized.The sensor can detect metal impurities more effectively.The main work and research content of this paper are as follows:1.Research on mutual inductance calculation between coils.The mutual inductance formula between two non coaxial rectangular coils and rectangular coils and ring coils is deduced in detail,and the correctness of mutual inductance formula is proved by comparing programming calculation and software simulation results.At the same time,the parameters affecting the mutual inductance are studied,which lays a theoretical foundation for the design of metal detector.2.Study on the output signal of a closed rectangular balanced coil system and the optimization of the system structure.The mathematical model of the system is established,the magnetic field distribution of the driving coil in the space is analyzed.Furthermore,the key parameters that affect the differential induction electromotive force in the equilibrium state are studied,and the optimal position of the balance coil and the conveyor belt is determined.3.By comparing the closed rectangular coil system with closed circular coil system and closed rectangular coil system with open rectangular system,it is concluded that closed rectangular system has more advantages in sensitivity and volume.