Magnetic Barkhausen Noise Measurement And Simulation Analysis In Soft Magnetic Materials

Magnetic Bakhausen noise signal(MBN)is commonly used for nondestructive testing of materials,and MBN of soft magnetic materials under lowfrequency magnetic field excitation can be used to study the deformation,stress and defects of such materials under actual working conditions.Soft magnetic materials are widely used in transformers,motor energy power equipment,and fatigue,stress,etc.will occur during their operation,and the use of MBN signals can be used for non-destructive and quantitative analysis of these phenomena.In this dissertation,experimental measurements and simulation analysis are carried out for the analysis of MBN signal characteristics of soft magnetic materials,and the main research contents and achievements are as follows:(1)A set of measurement systems that can measure soft magnetic materials MBN and hysteresis loops at the same time was established in the laboratory,including excitation module,signal detection module and signal processing module.These modules enable the generation of different excitation signals and can detect magnetic induction,magnetic and MBN signals simultaneously.The magnetic field strength signal is measured with a Hall element and corrected with a long straight solenoid.According to the characteristics of weak amplitude and high frequency of MBN signal,preamplification and filtering were processed and measured.The above signals are filtered,smoothed and other processes to eliminate interference such as power frequency and environmental noise to the greatest extent.(2)The magnetic field strength,magnetic induction strength and MBN signal of soft magnetic materials such as amorphous alloy and silicon steel sheet were measured by the experimental platform developed,and the signal was amplified,filtered and smoothed.Then,the envelope curve and MBN energy ring of MBN are plotted,and the variation trend of material MBN envelope under different applied magnetic field strength,excitation frequency and pick-up coil and sample winding coil are analyzed,as well as the change law of MBN energy value and rms value.The optimal excitation conditions for MBN signals of soft magnetic materials under this platform are discussed.(3)Simulate and analyze MBN signals.Based on the stochastic process model,JA model parameter extraction is carried out by PSO algorithm,and the JA model is solved by the fourth-order Rungekuta method,on this basis,the irreversible magnetized differential change rate is solved,and combined with the constructed random Poisson process series,the MBN signal simulation analysis of oriented silicon steel and non-oriented silicon steel is successfully carried out.