Measurement And Analysis Of Losses And Flux Densities In Laminated Steel Core And Solid Steel Plate

This subject is a part of the National Natural Science Fund Project,'The fine simulation of comprehensive electromagnetic properties of the electrical steel sheet and its composite structures in the computational electromagnetism'(Number:50777042).Accurate Calculation of transformer stray losses is closely related to the losses and flux densities measurements in laminated steel core and solid steel plate. There is a benchmark model, TEAM Workshop Problem 21 family, which is an engineering oriented model for power transformer and can be used for verifying the calculated results. However, with the successful development of large-capacity transformer and the use of new materials, it is necessary to design a new test model for finely simulating the macroscopic properties of ferromagnetic materials, especially the anisotropy of Si-Fe steel sheet in practical transformer products.Firstly, a supplementary model of TEAM Problem 21 is designed and produced, which the influence of anisotropy of Si-Fe sheet on the stray loss is investigated, and three groups of silicon steel laminations for magnetic shielding is made with the same material but different angles of the length direction and the rolling direction at 0°,45°and 90°.Secondly, experimental platform is built by using sophisticated power analyzer, data acquisition card, computer and other equipment. The magnetic flux densities and the losses are measured on the surface of the specified locations of the steel and copper plates, and the results obtained have some consulting value to the practical transformer design.Thirdly, three-dimensional eddy current field of the entire experimental model is analyzed by using commercial finite element analysis software ANSOFT, and the computational and experimental results are agreeable with each other by comparison, and the stray loss with different electrical shielding is analyzed. Based on these, and a reference for reasonable selection of the electrical shielding structure is provided to the transformer designer.Finally, a measurement system is developed by using virtual instruments and power amplifier for losses separating and magnetized curve drawing. The researches including design of the experimental models, development of variable frequency power supply, data acquisition and processing are fulfilled. The measurement system is used to measure the property of the solid plate of the TEAM Problem 21 supplementary model, and some meaningful results are obtained.