Research On Constant Current Excitation Measurement Technology Of Magnetoelectric Vibration Sensor

Magnetoelectric vibration sensor,also known as vibration pickup,has the advantages of simple structure,stable performance,large output signal etc.Most of the magnetoelectric vibration sensors are deployed in the field.At present,there are still some problems in the field calibration of the non-detachable vibration pickups installed in the field,such as the influence of the coupling inductance of the calibration coil on the calibration results.In order to solve this problem,the constant current excitation measurement technology of magnetoelectric vibration sensor are studied in this thesis.The specific research contents of this thesis are as follows:1)On the basis of understanding the research status at home and abroad,it is determined that the vibration pickup installed in the field can be calibrated by the self-calibration method.In order to eliminate the influence of the coil's coupling inductance on the calibration results,the method of constant current excitation vibration pickup is adopted.2)The sensitivity transfer functions of the vibration pick-up with constant voltage excitation and constant current excitation are analyzed theoretically,and the influence of the coil-coupled inductive reactance on the sensitivity of the field calibration method coil-coupledis determined.3)A constant current excitation signal generator is developed.The magnetoelectric vibration sensors with self-calibration coil are selected as the samples.The vibration absolute calibration and field calibration methods are used to test the frequency response characteristics of the vibration sensor,and the sensitivity of the vibration pickup at different frequency points is obtained.4)Through theoretical derivation and calculation,it is concluded that the measurement method of constant current excited vibration pickup can eliminate the influence of coil-coupled inductive reactance on the calibration result of vibration pickup;By comparing the two calibration methods,the results show that the relative error of the sensitivity of the constant current calibration method and the laser interference method is less than 1%,which proves the feasibility of the measurement method of the constant current excitation vibration pickup.For vibration pickups that are not removable on site,the research results of this thesis provide technical support for the field calibration method.