How can the radiation interference of intelligent low-voltage monitoring units be reduced?

Radiated interference reduction employs a combination of source suppression and shielding. The switching power supply uses an LLC resonant topology with RC absorption (100Ω + 470pF) added to the MOSFET. The clock circuit uses spread spectrum technology with a spread spectrum range of ±1.5%. The digital interface uses a PBZ1005B-501Z0T ferrite bead (500Ω@100MHz) in series. The chassis is made of 5052 aluminum alloy, 1.2mm thick, with conductive pads used in the gaps, providing a shielding effectiveness greater than 35dB@1GHz. Shielded filter connectors are installed at cable entry points. The PCB layout places high-speed signals on the inner layers, with ground copper on the outer layer. With this solution, radiated emissions in the 30MHz-1GHz frequency band are more than 8dB below the EN55032 Class B limit, meeting the IEC 61000-4-3 radiated emission test requirements.