Modeling And Simulation Of Electromagnetic Radiation From Switching Power Supplies

Switching power supply mostly work in high frequency state. The high speed on-off of the switch tube can cause the problem of strong electromagnetic interference. Radiation interference will not only reduce the working ability of the power supply itself, but also radiated energy to the outside of the system. Radiation to the outside of the system can reduce the energy of the surrounding electronic equipment running capacity or harm the health of the human body. Therefore, the research on the electromagnetic interference of switching power supply has the double meaning of theory and practical application.The research of interference source is to solve the problem of electromagnetic interference. Therefore, the radiation interference of power circuit is studied in this paper. After the analyzing the requirement of electromagnetic radiation and the mechanism of switching power supply. This article starts from the circuit basic components(resistance, inductance, capacitance, a power field effect transistor and diode) and the components of high frequency equivalent modeling. Then we model the switching power supply. And the time domain simulation and frequency domain analysis are carried out.In this paper, the principle of Boost PFC Dual circuit is analyzed, and the reason of the electromagnetic radiation of the main circuit is explored. The harmonic current of the switching circuit is the main source of the power converter. The parameters and models of main components of Boost PFC Dual are also given in this paper. The time domain simulation and frequency domain analysis of the main circuit are also given. From the results of frequency domain analysis, it is proved that the high frequency component of the current of the switching circuit and the high frequency component of the drain voltage of the switch tube are the main reasons for the electromagnetic radiation of the circuit.At the end of this paper, the electric dipole model and magnetic dipole model are used to simulate the electromagnetic field with the MATLAB software, and the distribution of the electric field and the magnetic field of the two models are analyzed. Analysis results show that, in the near field magnetic field intensity of electric dipole is smaller than the magnetic dipole's. But the distribution of the electric field and the magnetic field of changing trend are not quite different, and they are all distributed evenly.