Since the drafting of the yd/t983 standard, domestic communication power supply manufacturers have started researching electromagnetic compatibility. Due to the high cost of constructing electromagnetic compatibility testing instruments and testing sites, as well as the need for experienced R&D personnel, many manufacturers do not have their own laboratories, which poses certain difficulties in the research of electromagnetic compatibility. In the yd/t983 standard, the immunity index adopts the lower level of foreign standards. Except for lightning surge, ESD, and EFT indicators, other immunity indicators are relatively easy to meet the requirements. Electromagnetic interference indicators, such as conducted interference and radiated interference, are currently a hot topic in electromagnetic compatibility research due to their difficulty in meeting the requirements of the standards. Only a few manufacturers in China can fully meet the requirements of the relevant standards.
ZTE has established its own electromagnetic compatibility laboratory and has been committed to research on electromagnetic compatibility since the early stages of communication switching power supply development. The front stage of its communication switching power supply adopts the most advanced active power factor correction technology and lossless absorption circuit, while the rear stage DC/DC adopts zero voltage and zero current (zvzcs) phase shift resonance soft switching technology or dual transistor forward lossless absorption soft switching technology. Through professional power input and output filter design and lightning protection design, as well as anti-static design and fast transient pulse group design for the safety of the entire machine, digital interface circuit, and so on, The electromagnetic shielding design that is appropriate for the overall structure of the machine not only ensures a good electromagnetic environment, stable operation, and improved reliability inside the machine, but also enables the external current harmonics, electrical fluctuations and flickers, conducted interference, and radiation interference of the communication switching power supply to meet or exceed the A-level requirements specified in the CISPR22 standard. The input AC power cord can withstand at least ± 6kV (1.2/50 μ S and 8/20 μ The DC power line can withstand a surge voltage of at least ± 2kV due to the interference of the integrated wave surge voltage of s; The entire machine can withstand electrostatic discharge (ESD) interference of at least ± 8kV, electrical fast transient pulse train (EFT) of at least ± 4kV, high-frequency electromagnetic field interference of 3v/m, and power frequency magnetic field interference of 300a/m. The wide range of AC input voltage ensures that the switching power supply can operate normally after interference such as voltage drops, voltage transients, and short-term voltage interruptions of the entire machine. Professional collection of interference voltage from power grids across the country has been verified and analyzed on ZTE switching power supplies.
The electromagnetic compatibility indicators of ZTE communication series switching power supplies have fully met and exceeded all the indicators specified in yd/t983-1998 "Electromagnetic Compatibility Requirements and Measurement Methods for Communication Switching Power Supply Equipment". Some products have passed the full electromagnetic compatibility indicators in CE certification and FCC certification, making them truly environmentally friendly communication switching power supplies, especially suitable for mobile base stations, program-controlled switching equipment, IP phones Cable TV and other data communication transmission equipment are used in situations with strong electromagnetic interference such as railways, hydropower stations, and thermal power plants.
