In this work deals with magnetic fields for use in biomedicine. This solution involves the choice of the correct geometric arrangement of coils for generating magnetic field with a homogeneous distribution of magnetic induction of the widest possible area. The paper compares thre traditional types of coils, solenoid, toroid and Helmholtz coil. For Helmholtz and solenoid coil and is then carried out an analysis of the magnetic flux density in the inner space. Next part is devoted to electrical resonance in the LC circuit. This is then utilized for the development of pulsed magnetic field in the Helmholtz coil. It summarizes the theoretical and practical knowledge to design and construction of resonant converters. The end is devoted to the measurement of circuit parameters and verification of theoretical knowledge.

The master thesis is focused on the simulation of the toroid coils in Ansoft Maxwell 3D software, which uses finite element method for electromagnetic field simulation. Firstly the process creation of the geometric model toroid coil with seventy-five threaded is presented. It is necessary to debug this model and prepare it for the mesh generation. Physical properties are assign to this model and it gives rise to the physical model. We will set boundaries, excitation current, core material, winding material and the parameters for the mesh generations. New material Kashke K4000 will be created in the materials library and subsequently we will define its BH curve on the basis of datasheet. Analysis is made in two modes. Direct currents (7,5A; 10A; 15A; 20A; 25A) and (non)linear materials are used in magnetostatic solution. Toroid coil is excited by current pulse in transient solution. In Ansoft Maxwell Circuit editor a source which generates current pulse will be created. This excitation will be assigned to the toroid coil as an extern source through a terminal. Core material is linear in the case of transient analysis, because Ansoft Maxwell 3D doesn´t allow to use nonlinear material in this solution. Settings are different in transient and in magnetostatic analysis. End time and time step are entered to solve this task in transient analysis. Time points are entered too. Flux density and electromagnetic field strength are calculated in these time points and later it will be possible to view the results. Calculated fields are shown as the pictures in this thesis. The procedure how to use a field calculator in the postprocessing is given as well. The achievements are summarized in the conclusion.