The application and related test standard EMI test

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Consumers Association recently published a bulletin on the computer failure excessive radiation harassment, easily affect the power grid last device to cause the computer to crash. The main reason is the computer power supply terminal radiation harassment beyond the limits specified in the national standard, and this harassment can interfere with other electronic equipment to work, especially sensitive electronic equipment. With the development of science and technology, more and more digital, high-speed electrical and electronic equipment are widely used in all spheres of society, in promoting social development, along with the application of electrical and electronic equipment produced by electromagnetic interference but also to society It brings electromagnetic pollution. The electromagnetic pollution and water pollution, air pollution is known as the three major sources of pollution in today's society. With electromagnetic interference problems have become increasingly prominent, the International Special Committee on Radio Interference (CISPR) corresponding issued CISPR -16, CISPR-15, the European Commission issued a standard EN55015 and EN55022 standards. These measures and standards aimed at regulating point limit electromagnetic interference and other specifications of electronic products, to reduce electromagnetic interference caused by social problems.

EMI EMI (Electromagnetic Interference), have conducted and radiated interference two kinds. Conducted interference is the signal coupling through a conductive medium (interference) on an electric power network to another network. Radiated interference is the interference source through space to its signal coupling (interference) to another radio network. In the high-speed PCB and system design, high-frequency signal lines, integrated circuit pin, various types of connectors and so may be the source of interference with an antenna radiation characteristics, can emit electromagnetic wave and affect other systems or within the system to other subsystems normal work.


As we all know, EMC's goal is to test electrical and electronic equipment, and lighting equipment as one of the important piece, naturally, there is a corresponding constraint. Such as the US FCC certification, the EU's CE certification and so on LED lighting device made related test items. When talking to electromagnetic interference, in general, there are two sources of interference; a conduction disturbances, mainly the interference signal generated by the electronic device through the conductive media or public power line interference with each other, FCC certification conducted interference scanning LED lamps test frequencies from 0.15MHz to 30MHz start end, CE certification conducted interference scan test frequency from 30MHz to start 9KHz end. Another interference is radiated interference, mainly refers to the interference signal generated by the electronic device space coupling the electrical interference signal to another network or electronic equipment, LED lamps FCC certification of space radiation interference scan test frequency from 30MHz to 1GHz start end, CE certification of space radiation interference scan test frequency from 30KHz to 300MHz start over.

In the lighting industry, has tested 9KHz-30MHz band EMI in two ways, one is to use Antenna (antenna) and EMI receiver, which is based on the standard CISPR15, EN55015, GB17743. Lighting equipment for low frequency magnetic fields may arise, we need CISPR16-1-4 prescribed tricyclic antenna measuring low frequency magnetic radiation harassment. The main antenna is tested by the tricyclic and EMI receiver, the test required in a shielded room indoors. NOTE: tricyclic antenna X direction, Y direction and Z direction low frequency magnetic field component into RF signals, and fed by a coaxial switch three channels to measure EMI receiver; the other is using LISN test method, the test needs + by the EMI receiver and artificial mains network + LISN test software. Test system for measuring conducted disturbances lamps and lighting equipment in normal operating state of the power generated by the port harassment, LISN isolation RF signal, sampling, impedance matching, and provide an electrical path for the EUT, EMI receiver RF signal measurements and finally analyzed by EMI testing software, processing and sentenced limit. When the test will be conducted in a shielded room.

Meanwhile, 9KHz-300MHz band EMI test method is used CDN. In CISPR15, EN55015, and GB17743 standard also provides additional radiation field emission test method for lighting equipment, namely CDN common-mode voltage terminal method. Using CDN law, including EMI receiver, CDN and attenuators. Shield room can be carried out in the test.

For EMI test, the International Special Committee on Radio Interference (CISPR) issued a CISPR-16 radio interference and immunity measuring apparatus specifications, and for the lighting industry, the International Special Committee on Radio Interference CISPR-15 also proposed electronic lighting and related equipment Radio Interference characteristics limits and methods of measurement, based on national circumstances and countries are also introduced various types of EMI lighting test specifications, such as the EU out of EN55015-2007, China promulgated GB17743-1999 like. For EU countries, EN55015 standard (a reference to CISPR-15) is suitable for frequencies above 100Hz traditional lamp lighting, such as incandescent, fluorescent, self-commutated energy saving lamps. Typically such equipment does not exceed the frequency of 30MHz, the corresponding radiation interference limits in Table 1. But for the emerging LED lighting industry, typically frequency more than 30MHz, the CE certification clearly scanning frequency from 30MHz to 300MHz.

According to the relevant basic standards such as CISPR16, Shantou force developed and produced two EMI test equipment, lighting and traditional and new industry standards, the two scanning frequencies of the different devices, KH3962 EMI scanning frequency 9KHz ~ 300MHz, for LED and traditional lighting testing equipment; KH3961 EMI scanning frequency 9KHz ~ 30MHz is mainly suitable for detecting conventional lighting equipment. The analyte is determined whether the standards, we refer to the peak, quasi-peak and average of three values ​​to determine, taking into account the differences in standards, the software can call GB17743, FCC, EN55015, GB4343 and other criteria directly.