Manufacturing Of 1J85 Soft Magnetic Material Initial Permeability Measurement Instrument

1J85 soft magnetic material is an indispensable functional material in production and daily life.It has high initial permeability and has been widely used in these devices with strict sensitivity requirements which are low-frequency or high-frequency input-output transformers,common-mode inductors,and high-precision current transformers.The initial permeability is one of the important parameters for judging the performance of magnetic components.Accurately measuring the initial permeability,whether for the production,research,and development,acceptance of soft magnetic materials,or the formation of industrial finished products or raw materials for other devices are all vital.Aiming at the parameter of initial permeability of 1J85 soft magnetic material,this paper analyzes the main factors that affect the measurement accuracy in the measurement process and develops a high-precision measuring instrument for measuring the initial permeability of 1J85.This paper focuses on the weak signal of the initial magnetic permeability of soft magnetic materials,follows the national standard for static magnetic performance measurement of soft magnetic alloys,and combines the advantages and disadvantages of magnetic measuring instruments at home and abroad,by consulting the relevant data of soft magnetic materials and the measurement methods of their parameters,the overall measurement scheme of the system is determined on this basis;For the characteristics of weak initial magnetic permeability measurement signal of 1J85 soft magnetic materials,the influence of the accuracy of the electronic integrator is analyzed,and the hardware of the electronic integrator is optimized.A series of measures are taken to improve the stability and accuracy of the electronic integrator,including the selection of operational amplifier,the design of bipolar symmetrical power supply and zeroing circuit,and the determination of integral time constant,integral resistance and integral capacitance;To achieve the digitization and intelligence of the measuring instrument and to solve the problem of a large amount of experimental data processing,data acquisition and processing system with STM32F103RCT6 was designed,and the LCD module and software algorithm were used to reduce integrated drift and improve its measurement accuracy;Following the working principle of volt-second generator calibration the electronic integrator,volt-second magnitude signal generator circuit,the PWM control circuit,and a control circuit unit was designed and verified by experiments calibration accuracy thereof can be used to calibrate an electronic integrator.Finally,using the sample measurement value provided by Shaanxi Metrology Institute as the reference value,the initial permeability of 1J85 soft magnetic material has been measured,and the final measurement result has been compared with the reference value.The experimentalresults show that the measurement system designed by this subject can effectively measure the initial permeability of soft magnetic materials,and the measurement error is less than 5%.