Generation mechanism and suppression technology of electromagnetic interference of switching power supply
With the development of modern electronic technology and power devices, switch mode power supplies are widely used in fields such as computer and peripheral communication, automatic control, household appliances, etc. due to their small size, light weight, high performance, and high reliability, providing great help for people's production, life, and social construction. However, with the rapid development of modern electronic technology and the widespread application of electronic and electrical equipment, the distance between various electronic and electrical devices in the same working environment is getting closer, and the external environment of electronic circuit operation is further deteriorating. Due to operating in a high-frequency switching state, switching power supplies generate high rates of current and voltage changes internally, resulting in strong electromagnetic interference. Electromagnetic interference signals not only pollute the power grid, but also directly affect the normal operation of other electrical equipment and even the power supply itself. Moreover, as radiation interference, they invade space, causing electromagnetic pollution and restricting people's production and life.
Suppression of Electromagnetic Interference in Switching Power Supply
The three elements that form electromagnetic interference are the interference source, propagation path, and disturbed equipment. Therefore, suppressing electromagnetic interference should be addressed from these three aspects. The purpose is to suppress interference sources, eliminate coupling and radiation between interference sources and disturbed devices, and improve the anti-interference ability of disturbed devices, thereby improving the electromagnetic compatibility performance of switching power supplies.
Using filters to suppress electromagnetic interference
Filtering is an important method for suppressing electromagnetic interference, which can effectively suppress the entry of electromagnetic interference into equipment in the power grid, and also suppress the entry of electromagnetic interference from equipment into the power grid. Installing switch power filters in the input and output circuits of switch power supplies can not only solve the problem of conducted interference, but also be an important weapon for solving radiation interference. The filtering suppression technology is divided into two methods: passive filtering and active filtering.
Passive filtering technology
Passive filtering circuits are simple, cost-effective, and reliable, making them an effective way to suppress electromagnetic interference. Passive filters are composed of inductive, capacitive, and resistive elements, and their direct function is to solve the problem of conduction emission.
