An alternative method for conducted immunity tests using multiple CDNs

Measuring immunity is very important when it comes to studying the electromagnetic compatibility (EMC) of a device. At present, most of the standards relating to conducted immunity tests are designed for laboratory use, and the conducted immunity tests are often performed by using coupling/decoupling networks (CDN), in accordance with the international standard EN61000-4-6. However, the laboratory equipment has some limitations. If the (EUT) requires high currents, it is not possible to use one CDN on the mains side because a single CDN cannot handle the high currents involved. To overcome this problem, an alternative method is proposed for conducted immunity tests using multiple CDNs by splitting the mains current sufficiently to meet the current specifications of each individual CDN. From these tests, correction factors (CF) are extracted based on the analysis of loop impedances and injected loop currents in the standard laboratory test setups and in the alternative multi-CDN test setups. Finally, a link is established between the reference method and the multi-CDN method, and then, the equalization between them is realized with these correction factors.