Research On The Measurement Method Of Superconducting Strong Magnetic Field Based On The Coil Rotation Method

With the development and exploration of new science,the extreme conditions created by strong magnetic field are often needed as the research environment.Superconducting high magnetic field can provide long-term and stable magnetic field,which plays an important role in the fields of electrical engineering,medical treatment,transportation,military industry and scientific experiment.The measurement methods of strong magnetic field mainly include nuclear magnetic resonance method,magneto-optical effect method,Hall effect method,electromagnetic induction method,etc.because the upper limit of traceability of national standard magnetic field is 12 Tesla,the standard measurement of magnetic field higher than 12 Tesla is bound to be limited.With the increasing range of magnetic induction intensity of superconducting magnet,there is an urgent need for a more accurate high magnetic field measurement method suitable for superconducting magnet system environment and measuring range of more than 12 Tesla.Based on the classical electromagnetic induction method,this paper proposes a method of measuring the superconducting magnetic field based on the coil rotation method.Through the analysis and research of the superconducting magnet environment,a set of rotating coil measurement system suitable for the superconducting magnetic field is designed,which can be used to measure the superconducting magnetic field.The coil probe is calibrated in the national standard magnetic field,and then the magnetic field measurement experiment is carried out.This method is traceable by standard magnetic field and has high accuracy.In the aspect of signal acquisition,the phase-locked amplifier is used to collect the induced electromotive force,and the key part is to obtain the synchronous reference signal.By installing the encoder in the same frequency drive position of the coil,the hardware circuit is designed to realize the real-time acquisition of the reference signal.Good synchronous reference signal improves the measurement accuracy of electromotive force directly.The designed power transmission device can fix the position of the coil probe in the magnetic field uniform region,transfer the kinetic energy of the motor end to the coil probe through the transmission rod,and realize the change of the transmission direction in the narrow magnetic field space,so that the coil probe can rotate perpendicular to the magnetic field direction driven by the motor,generate the induced electromotive force,and finally achieve the purpose of measuring the magnetic field.The error between the measured results and the standard magnetic field is less than3%,which can realize the standard measurement of superconducting magnetic field.