Passive Cancellation of Common-Mode Electromagnetic Interference in Switching Power Converters

dc.contributor.authorCochrane, Danielen
dc.contributor.committeechairChen, Dan Y.en
dc.contributor.committeememberBoroyevich, Dushanen
dc.contributor.committeememberLai, Jih-Shengen
dc.contributor.departmentElectrical and Computer Engineeringen
dc.description.abstractIt is well known that common-mode (CM) conducted electromagnetic interference (EMI) is caused by the common-mode current flowing through the parasitic capacitance of transistors, diodes, and transformers to ground in the power circuit. Because of the potential for interference with other systems as well as governmental regulations, it is necessary to attenuate this noise. Ordinarily this must be accomplished by using a magnetic choke on the input power lines, which can result in large penalties to the overall size, weight, and cost of the completed system. In order to lessen the requirement for this magnetic choke, there has been in recent years a desire to introduce noise cancellation techniques to the area of EMI. This text introduces a method of canceling the common-mode EMI by using a compensating transformer winding and a capacitor. Compared with active cancellation techniques, it is much simpler and requires no additional transistors and gate-drive circuitry since it merely adds a small copper winding and a small capacitor. By using this technique the size of the EMI filter can be reduced, especially for applications requiring high currents. In this thesis a survey of CM noise reduction techniques is presented, encompassing conventional and active cancellation techniques. The new method for passive noise cancellation is presented, which is then applied to families of isolated DC/DC converters, non-isolated DC/DC converters, and DC/AC inverters and motor drives. The method, results, and ramifications of this technique are presented in order of appearance.en
dc.description.degreeMaster of Scienceen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.subjectSwitching Power Suppliesen
dc.subjectNoise Reductionen
dc.subjectNoise Cancellationen
dc.titlePassive Cancellation of Common-Mode Electromagnetic Interference in Switching Power Convertersen
dc.typeThesisen and Computer Engineeringen Polytechnic Institute and State Universityen of Scienceen


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