Method for suppressing power noise of socket

Update:14-12-2019
Summary:

For the socket power supply, its drive circuit, control […]

For the socket power supply, its drive circuit, control circuit, protection circuit, etc. are easily subject to electromagnetic interference and malfunction. The socket power supply itself is a strong noise source, which may emit electromagnetic interference during normal operation. The noise generated by the socket power supply has a wide frequency range and high intensity. These electromagnetic interference noises also pollute the electromagnetic environment through radiation and conduction, thereby affecting the normal operation of other electronic equipment.
The interference that is transmitted by electromagnetic radiation in space is called radiated noise, and it decreases with distance. Disturbance transmitted through various connection lines of the device (such as power lines, signal lines, control lines, data lines, public ground lines, etc.) is called conducted noise. Effective measures must be taken to suppress the transmission of noise interference signals and prevent these noises from entering and exiting the socket power supply. In terms of suppressing EMI radiation noise, electromagnetic shielding is the best method. In terms of suppressing EMI conducted noise, the use of EMI filters is an effective method.
The use of shielding technology can effectively suppress radiated interference. For example, the socket power supply uses a metal shell shield box or a shielded mesh plate, and is made of a copper or aluminum plate with good conductivity (the thickness of the copper plate or aluminum plate is generally 0.5-1 mm). In order to dissipate heat, ventilation holes should be provided on the wall of the shielding box, and the holes should be round. In order to make good contact at the seam of the shielding box, a reed can be added at the seam. When the frequency is high, the leakage of the electromagnetic field in the gap is generally more serious than the hole, and the leakage of the magnetic field is larger than the leakage of the electric field in the gap. Therefore, when the shield box and the cover plate are connected by screws, the distance between the screws should not be too large, and they should be tightened to reduce the gap.
When the socket power supply is directly connected to the mains power grid, there is a two-way electromagnetic interference effect between the power grid and the power supply equipment: the socket power supply introduces grid noise from the power supply incoming line, and the harmonic and parasitic energy generated by the socket power supply are transmitted through the power line Wait for noise to pass out. To reduce the conducted noise of the power line. An electromagnetic interference filter should be added at the power input.