Grobler, InusGitau, Michael Njoroge2017-08-042017-08-042017-07Grobler, I. & Gitau, M.N. 2017, 'Analysis, modelling and measurement of the effects of aluminium and polymer heatsinks on conducted electromagnetic compatibility in DC-DC converters', IET Science, Measurement and Technology, vol. 11, no. 4, pp. 414-422.1751-8830 (online)1751-8822 (print)10.1049/iet-smt.2016.0218http://hdl.handle.net/2263/61590Effects 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.en© The Institution of Engineering and Technology 2017. This paper is a postprint of a paper submitted to IET Science Measurement and Technology and accepted for publication in and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library.PolymersAluminiumHeat sinksElectromagnetic compatibilityDC-DC power convertorsElectromagnetic interferenceCoolingOscilloscopesData recordingAluminium heat sinkConducted electromagnetic compatibilityPolymer heat sink materialElectromagnetic interference noiseOscilloscope data recordingDevice under testSuspended feed-lineGrounded copper sheetWideband two-port line impedance stabilising networkMIL-STD-461F accredited test environmentHeat dissipationConductive fillerSolid aluminium materialStep-down DC-DC converter circuitDifferential mode modelHeat sink impedanceHeat sink-to-device capacitanceNoise path impedanceCommon-mode noiseEMI noiseElectromagnetic interference (EMI)Common-mode (CM) noiseLine impedance stabilising network (LISN)Postprint Article