Time Domain Finite Difference Method And Its Switching Power Supply Electromagnetic Radiation Calculation

This thesis contributed to the comprehensive study of the Finite-Difference Time-Domain (FDTD) method and its application to the numerical computation of radiated electromagnetic fields in switched mode power supplies. The work includes mainly three parts: the study on the performance of PML absorbing boundary condition applied to pseudo low frequency electromagnetic problems; the validation of the FDTD method with PML absorbing boundary conditions and the corresponding computer software based on the numerical study of the electromagnetic field of an electric dipole antenna, and its application to the numerical computation of radiated electromagnetic fields in switched mode power supplies; the development of an improved alternating direction implicit finite-difference time-domain method.In the study on the performances of PML absorbing boundary conditions, the thesis improved, respectively, the 2D and 3D FDTD methods with PML absorbing boundary condition, and constructed the corresponding computer software. By means of numerical computations, the thesis investigated the stability and the absorbing property of the PML absorbing boundary condition. In addition, the thesis also gives a lot of numerical results and some practical conclusions to facilitate the application of the proposed FDTD method.In the following section, the thesis demonstrated the robustness of the proposed method in the computation of radiated electromagnetic fields of switched mode power supplies by means of a numerical study on the electromagnetic fields of an electric dipole antenna. To show the applicability of the proposed algorithm for engineering problems, the thesis computed the radiated electromagnetic field of a switched mode power supply, with special attention on the analysis of the EMI in the electronic control circuit. Different numerical results and two valuable guidelines are drawn.To overcome the drawback of the FDTD method in computing the pseudo low frequency electromagnetic problems, in the final, based on comprehensive study on the present ADI-FDTD method, the thesis proposed an improved 2D ADI-FDTD method. The numerical results show that the proposed method is more unconditional stable and computationally accurate than the conventional ADI-FDTD ones.