HBFEM for Nonlinear Magnetic Field Problems

This chapter discusses mainly the numerical modeling and analysis of electromagnetic fields in switching power supplies. It uses harmonic balance analysis, combined with the finite element method (FEM), to solve problems arising from non-linear, harmonic, eddy-current and power loss problems of transformers used in switching power supplies. The chapter also discusses the harmonic balance-FEM (HBFEM) model and computed results, compared with experimental results. The harmonic components of current and magnetic flux can help to accurately analyze and design the magnetic core and winding structures, and further determine the power loss and leakage flux in the magnetic system. The numerical model of voltage excitation with a nonlinear magnetic field is more accurate than conventional magnetic field-only analysis. The EM full wave solution can be obtained from HBFEM based numerical computation. To verify the HBFEM based solution, a single-phase direct current (DC)-biased switching transformer with a voltage source driven model is used.