Filtering is an effective method for suppressing conducted interference, playing a crucial role in the electromagnetic compatibility (EMC) design of equipment or systems. As a key component for suppressing conducted interference on power lines, EMI filters can inhibit interference from the power grid that may harm the power source itself, as well as interference generated by switching power supplies and fed back into the grid. In filter circuits, various filter elements are also employed, such as through-hole capacitors, three-terminal capacitors, and ferrite cores, which can enhance the filtering characteristics of the circuit. Appropriately designing or selecting filters, and correctly installing and using them, is an essential part of anti-interference technology.
Selecting shielding techniques can effectively suppress electromagnetic interference (EMI) generated by switch-mode power supplies. This involves using conductive materials to shield electric fields and high permeability materials to shield magnetic fields. The purpose of shielding is twofold: to confine the internal radiation of electromagnetic energy from escaping and to prevent external radiation interference from entering the internal area. The principle is based on the reflective, absorbent, and directive effects of the shielding body. To suppress the radiation generated by switch-mode power supplies and the electromagnetic interference on other electronic devices, the shielding cover can be processed according to the magnetic field shielding method, and then connected to the system's housing and ground, thereby effectively shielding the electromagnetic field. Establishing conductive pathways between two points allows electronic devices or components to be connected to a reference point called "ground." Grounding is a primary method for switch-mode power supply devices to suppress electromagnetic interference, as connecting certain parts of the power supply to the earth can mitigate interference. Aviation ground power 2, 2,36V aviation power 1, 400HZ inverter power supply 7, 115/200V power supply 2, 27V DC power supply 5, 400HZ power supply 12, aviation power
In circuit system planning, the principle of "single point grounding" should be followed. Assuming multiple points of grounding are formed, it will present a closed grounding loop, and when magnetic lines pass through this loop, magnetic induction noise will occur. In reality, achieving a "single point grounding" is difficult. Therefore, to reduce grounding impedance and eliminate the impact of distributed capacitance, flat grounding or multi-point grounding is adopted, using a conductive plane as a reference ground, with each grounded component connected as close as possible to this reference ground. To further minimize the voltage drop of the grounding loop, bypass capacitors can be used to reduce the amplitude of the return current. In circuit systems where both low-frequency and high-frequency signals coexist, the ground lines of the low-frequency, high-frequency, and power circuits should be connected separately before being connected to a common reference point.
