Conducted Emission Measurement of Multiphase On-Board Buck Converters

Switching – mode power supplies (SMPS) are often used elements in satellite power systems. Due to their switching mode behavior, they have good conversion efficiency, but they also produce considerable conducted and radiated noise emission, which can disturb the operation of other on-board devices. Because of this the electromagnetic interference (EMI) caused by SMPS units is a well-studied subject and there is still numerous ongoing research in this topic. There are many techniques, which can be used to reduce the EMI of on-board DC-DC converters, one of them is the interleaving of the switching operation of multiple SMPS units. This method is a suitable solution for converters operating from a common power bus. In this paper we are going to present the test procedure used for SMPS conducted emission measurement and the noise cancellation effect of interleaving will be demonstrated with a setup consisting of four Buck converters. The noise reduction effect of this method will be also inspected under different circumstances, which can typically occur in a power system.