Solution of Magnetic Characteristic Parameters Using Analogizing Finite Element Method for Ferrite Core Inductor

Only the azimuthal component of magnetic field intensity H inside magnetic core exits when it comes to a closely-packed ferrite inductor. The field presents an axisymmetric mode distribution when H is selected as the degree of freedom (DOF). The field characteristic of an inductor loaded current with azimuthal direction is of symmetrical also when magnetic vector potential A is selected as DOF. The differential equations for two type fields adopting their corresponding DOFs are deduced. While there are the same material properties, shapes and similar boundary conditions, the field distribution of the former can be solved analogically by the later one. Therefore, the magnetic field distribution and corresponding magnetic characteristic parameters for a closely-packed ferrite inductor can be solved by the way which magnetic vector potential A is selected as DOF and the field is of symmetrical. In condition of considering parasitic capacitance, the model consisting of lumped parameters R-L-C for 2 inductors is proposed, and the measurable series model only including resistance and inductance can be obtained. Calculated equivalent resistance, inductance and phase angle are in good agreement with the measurement ones up to 10 MHz. As a consequence, it is shown that the model is correct and the results have a good precision. An approach of analogizing theoretically for the ferrite core inductor in the application of power electronics is provided.