The Electronmagnetic Compatibility Analysis And Design On Switching Power Supply

With the development of science and technology, switching power supply intoday’s society plays an important role, it is widely used in various fields. Switchingpower supply is developing toward smaller, more frequent, lighter direction, at themoment it also needs the higher ability of electromagnetic interference suppression.High-frequency switching power supply is an electromagnetic compatibility issuesgathering place. Switching power supply is not only vulnerable to outside interference,itself also is a great source of interference. So, their own internal mutual interferenceproblems and the degree of interference of the outside world should be both consideredin design process.In this paper, flyback switching power supply is studied, The research focuses onconducted interference source and radiated interference sources and generationmechanism of the power system. At last a complete notebook power system is designed.The main research works are as follows:(1) This paper introduces the generation mechanism of flyback switching powersupply, the design parameters of flyback switching power supply is calculated.According to the conducted interference mechanism and characteristics of flybackswitching power supply, EMC design is conducted targeting on all aspects (lightning,filtering, buffering, rectifier, etc.). A switch flyback switching power supply systemfrom220V to19V is designed at last. According to the high-frequency characteristics ofcapacitance and inductance, high Saber models are built in various modules of thecircuit.Compared with the theoretical analysis, the simulation results verify thefeasibility of the theoretical analysis.(2) The key devices which can cause electromagnetic interference are analyzedand simulated for studying the influence of the parasitic parameters on the switchingpower supply system performance. The filters, and MOS tube simulation is run in Sabersoftware for the analysis of time-domain simulation while the transformer2Dsimulation is run in An soft Maxwell software. The results show that different degreesof parasitic effects may lead to different switching power supply performance. By themechanism of switching power supply system radiation interference. Switching powersupply circuit can spread interference to the surrounding in the form of electromagnetic radiation. In this paper, the antenna simulation model is established to equivalent theloop circuit of power supply system. Antenna model is created and analyzed in HFSSsoftware.(3) At last, switching power supply system is achieved and tested.According to the switching power supply system conducted interference andradiated interference simulation analysis, the potential sources of electromagneticinterference effects of switching power supply which play a helpful role in validitydesign of the switching power supply are given. The radiation interference simulation ishelpful to PCB board production and shortens the product development cycle.