EMI Measurement Application and Relative Test Standards

Along with the technical development, more and more digital and high speed electronic and electric devices are widely applied to vary industries. Those equipments push the society developing, and the same time they bring the electromagnetic pollution problem to the society. Electromagnetic pollution, water pollution and air pollution are the three big pollution sources for modern life. Go with series electromagnetic problem, IEC 61000-4-4, IEC 61000-4-5, IEC 61000-4-11, CISPR -16, CISPR-15 and other relative standards are introduced by IEC. The main purpose for those standards is to limit radio disturbance and put forward the method of measurement of electronic and electric device, so that to decrease the society problem which brings by electromagnetic disturbance.

As we know, the test object for EMC is electronic and electric device, among them, lighting is an important part which should do the EMC test naturally. Like FCC from America and CE from European Union, both of them request EMC measurement of LED lighting device. When talk about electromagnetic disturbance, generally it indicates two disturbance sources, one is conductive interference (EMS), it means that the disturbance signal will affect the EUT by conducting medium or public power supply; according to FCC, the LED lighting should do the conductive interference test at the frequency of 0.15MHz to 30MHz; but according to CE, it requests to do the test at the frequency of 9KHz to 30MHz. The other is radio disturbance (EMI0, it means the disturbance signal will pass to electric network or device by the way of space coupling; according to FCC, the LED lighting should do the radio disturbance test at the frequency of 30MHz to 1GHz; but according to CE, it requests to do the test at the frequency of 30KHz to 300MHz.

For EMI test, the International Special Committee on Radio Interference (CISPR) introduced CISPR-16 Radio Disturbance and Immunity Measuring Apparatus-Measuring Apparatus; for lighting industry, they introduced CISPR-15 Limits and Methods of Measurement of Radio Disturbance Characteristics of Electrical Lighting and Similar Equipments. Meanwhile, some countries push their own Lighting EMI test criterions according to their real situation, like EN55015-2007(quote CISPR-15) from EU counties, GB17743-1999 from China and etc. For EU countries, EN55015 is applied to the traditional lightings which radio disturbance field exceeds 1000Hz, like incandescent lamp luminaries, fluorescent lamp luminaries, self-ballasted lamps and etc. generally, the frequency of the traditional lamps will not exceed 30MHz, the corresponding radiated electromagnetic disturbance limit as table 1. But for LED lighting, the frequency will exceed 30MHz, so according to CE, the frequency scanning range should be from 30MHz to 300MHz.

Table 1:

Radiated Electromagnetic Disturbance Limits
Frequency Limits for Loop Diameter Db (µA)
2m 3m 4m
9KHz to 70KHz 88 81 85
70KHz to 150KHz 88 to 58** 81 to 51** 75 to 45**
150KHz to 2.2MHz 58 to 26** 51 to 22** 45 to 16**
2.2MHz to 3.0MHz 58 51 45
3.0MHz to 30MHz 22 1.5 to 16*** 9 to 12***

Base on CISPR16, Lisun Group developed two EMI test systems. According to the standards for traditional Lightings and new LED lightings, the frequency scanning range is different. The scanning frequency for KH3962 is 9 KHz to 300MHz, which is applied to LED and traditional lighting test; the scanning frequency for KH3961 is 9 KHz to 30MHz, which is applied to traditional lighting test. Both of them input three data to judge if the EUT can pass the test or not, that is PK, QP and AV. And user is freely to setup the standards (like GB17743, FCC, EN55015, GB4343) directly in the software.

Surely, besides the lighting industry, KH3962/KH3691 EMI test system is widely used in other electronic and electric industries, like Captial power system Ltd from India, Lumitec Ltd. from Thailand and other companies. The reason why Lisun Group wins so many trust and support from world famous companies and third labs is because we always practice the motto of right products, right price and right service. See from the feedback of our customers, we enjoy good reputation among our customers. No matter in the pass or future, Lisun Group will always give back the qualified products and superior service to our customer.