Research And Application Of Miniaturization Technology Of Electromagnetic Characteristic Detection Device Of Static Ferromagnetic Element

With the development of power system and transformation equipment technology,higher requirements are put forward for electrical equipment.Static ferromagnetic elements such as transformers and mutual inductors with new technology and new materials are widely used in power system.If their performance does not meet the design and operation requirements,power system blackout will be caused,resulting in significant economic losses and social impact The investigation and statistics show that the selection of core and winding and manufacturing process are the main reasons for the damage of static ferromagnetic components.The electromagnetic characteristic test of static ferromagnetic components is an important means to ensure its performance.The test can reflect the poor insulation,looseness,displacement,turn to turn short circuit and process defects of the core and coil.However,the conventional test methods have the disadvantages of high test voltage,large equipment volume,heavy weight,high test efficiency and high safety risk.The new frequency conversion test method generally has the problems of test accuracy,poor consistency and high price.Therefore,in view of the problems existing in the electromagnetic characteristics detection of static ferromagnetic components,this paper studies the small-scale electromagnetic characteristics detection of static ferromagnetic components Chemical technology and equipment.The core idea of the miniaturization of the static ferromagnetic element testing device is to use the low frequency power supply as the excitation source.Based on the Lucas model,an equivalent mathematical model of static ferromagnetic element is established for frequency conversion test.In the model,DC resistance,leakage inductance,eddy current equivalent resistance,hysteresis loss and other parameters are related to frequency.Secondly,the calculation and analysis method of each electromagnetic characteristic parameter under low frequency excitation is proposed.The excitation voltage of different frequency and the same flux density is applied to the static ferromagnetic element,the matrix of excitation voltage U and excitation current I is measured,eddy current loss coefficient we and hysteresis loss coefficient wh are calculated,eddy current loss current i_e,hysteresis loss current I_h are separated,fundamental component and harmonic component of I_h are separated,The leakage inductance,excitation characteristics and harmonic current can be obtained by calculating the power frequency excitation current.Finally,the residual magnetism of static ferromagnetic elements is measured by using the DC voltage source with polarity reversal.Finally,the miniaturized detection device is designed and developed,including EMI filter,APFC circuit,full bridge DC-DC isolation circuit,sine wave inverter circuit,square wave circuit,sampling control circuit,etc.the electromagnetic characteristics of transformer and transformer are tested by the developed prototype,and the test results are in good agreement with the conventional power frequency test methods.Through theoretical analysis,prototype development and experimental verification,it is shown that the miniaturization device of static ferromagnetic element electromagnetic characteristics detection can greatly reduce the test equipment capacity,volume weight,test voltage and safety risk,improve the test efficiency,and achieve the research goal of miniaturization of detection device.