Properties of a magnetic concrete core transformer for application in wireless power transfer systems

A combination of ferrimagnetic and ferromagnetic inclusions were blended within a diamagnetic Portland cement matrix to increase bulk relative permeability for possible application in wireless power transfer. The objective of this study is to quantify the interactive flux exchange coupling between ferritic inclusions of different composition, shape, size, volume fraction, core geometry, and coil winding configuration. Cores made of cement mortar and various combinations of ferrimagnetic and ferromagnetic inclusions were cast and the permeability was quantified. A total of 21 different mix combinations were considered. ANOVA was used to assess the level of significance of each individual inclusion and their interaction with each other with respect to relative magnetic permeability. X-Ray diffraction, thermogravimetric analysis, and mechanical compression tests were also completed. The results suggest that powder and fibrous ferritic inclusions at a volume fraction greater than 10% can reduce flux leakage, reduce hysteresis core loss, and significantly increase relative permeability. A steel reinforced magnetic concrete CI core can achieve a peak flux of 100mT and relative permeability of 28 when the cement matrix contains 20% volume fraction of ferritic fiber and powder inclusions. (C) 2019 Elsevier Ltd. All rights reserved.