Effects of polymer heatsink materials on electromagnetic interference (EMI) noise in converters have not been adequately investigated. Heatsinks provide a path to ground for the common-mode (CM) noise. Selecting an appropriate heatsink material can therefore help reduce CM noise by increasing noise path impedance. The critical parameter is the heatsink-to-device capacitance and accurate models of the heatsink impedance need to be developed. This is necessary for results that are accurate enough to allow prequalification of a converter as would happen in an accredited environment. However, simplified CM and differential-mode models of the step-down DC-DC converter are adequate to predict the effects of the heatsink on the conducted noise. This study will demonstrate that compared to a solid aluminium material, using polymer material incorporating conductive fillers can greatly lower the device-to-heatsink capacitance, and still be adequate for heat dissipation in low power converters. This in turn reduces CM noise in the frequency band below 30 MHz. The measurement test setup is configured according to MIL-STD-461F standard. It consists of a wideband two-port line impedance stabilising network (LISN), a properly grounded copper sheet, a suspended feed-line from the LISN to the device under test and an oscilloscope recording the data.
Grobler, Inus; Gitau, M.N. (Michael)(Institution of Engineering and Technology, 2017-07)
Conducted electromagnetic compatibility (EMC) noise qualification tests are normally carried out after a prototype has been designed, built and tested and the process is repeated in the event of non-compliance. The ability ...
Sinha, Saurabh; Stander, Tinus; International Conference on Radioelektronika, (23rd : 2013 : Pardubice, Czech Republic)(Institute of Electrical and Electronics Engineers, 2013-04)
Gigahertz transverse electromagnetic (GTEM) cells
are used extensively in industry for testing the impact of defined
E-fields on devices sensitive to electromagnetic interference.
Compared to anechoic chambers, GTEM ...
Pretorius, Johann Christiaan(University of Pretoria, 2013)
The electromagnetic wave absorption characteristics of composite cement-based building
material have attracted much interest in recent times. Researchers have mainly focused on
the 2 GHz to 12 GHz frequency range. Mobile ...