Harmonic Analysis And Its Influence In The Measurement Of Elastic Permeability

Soft magnetic materials are widely used in communication components, LCD displays, solar photovoltaic industry, electronic products of coils and inductors, green lighting and other fields. The prospect of soft magnetic materials’development is very broad with the rapid growth of energy-saving environmental protection industry. The designers want the magnetic properties of the soft magnetic materials and dynamic magnetic characters to be exact in practical application. Elastic permeability is one of the basic parameters of dynamic magnetic characters, is the required parameter for inspection while the manufacturer of various types of sensors purchasing materials. The influence of circuit harmonic wave cause the elastic permeability measurement to be larger deviations and lower accuracy, meanwhile the complicated operation, inefficiency and the sample wastage of the traditional methods became more unbearable for manufacturers. So, it is important to fulfill the true effective value (TRMS) measurements and implementation of automated measurement of elastic permeability based on microcontroller designment.By analyzing several normal methods for elastic permeability measurement of soft magnetic materials, it shows that the most important point for the accuracy measurement is harmonic wave. This means that the high precision of TRMS measurement can be derived from weaken the influence of harmonic. This work is arranged as follows:(1) Three voltage method is used for elastic permeability measurement in this work, which is chosen from various current methods for flexible magnetic permeability measurement according to the criteria of national metrology institute.(2) Elastic permeability measurement is interfered by many factors, such as the stability of power system, the sample preparation and the system sensitivity, etc. Using a serials of orthogonal experiments to get rid of the interfering factors on many soft magnetic materials like1J85,1J50, and finally made the results perfectly suit the national standards.(3) Ensure the measurement of TRMS effective by using the single chip microcomputer (SCM), and improve the measurement accuracy of the device between0.7and5V through a large number of experiments for error compensation, with AD637as the core part of TRMS converter circuit.(4) The input signal of TRMS in SCM is the weak voltage handled by three voltage method which has been amplified by ICL7650, then design the accuracy of amplifier circuit of ICL7650after analyzing the characteristic of amplified circuit.In general, this work optimizes the interference factors and improves the deficiencies in three voltage method measurement, weaken the influence of harmonic and finally get the device for elastic permeability measurement, which implement automated measurement based on SCM-52with high measurement stability which reach the required accuracy of national standards.