Frequency Domain Conductive Electromagnetic Interference Modeling and Prediction with Parasitics Extraction for Inverters

This dissertation is to focus on the development of modeling and simulation methodology to predict conductive electromagnetic interference (EMI) for high power converters. Conventionally, the EMI prediction relies on the Fast Fourier Transformation (FFT) method with the time-domain simulation result that requires long hours of simulation and a large amount of data. The proposed approach is to use the frequency-domain analysis technique that computes the EMI spectrum directly by decomposing noise sources and their propagation paths. This method not only largely reduces the computational effort, but also provides the insightful information about the critical components of the EMI generation and distribution. The study was first applied to a dc/dc chopper circuit by deriving the high frequency equivalent circuit model for differential mode (DM) and common mode (CM) EMIs. The noise source was modeled as the trapezoidal current and voltage pulses. The noise cut-off frequency was identified as a function of the rise time and fall time of the trapezoidal waves. The noise propagation path was modeled as lumped parasitic inductors and capacitors, and additional noise cut-off frequency was identified as the function of parasitic components. . Using the noise source and path models, the proposed method effectively predicts the EMI performance, and the results were verified with the hardware experiments. With the well-proven EMI prediction methodology with a dc/dc chopper, the method was then extended to the prediction of DM and CM EMIs of three-phase inverters under complex pulse width modulation (PWM) patterns. The inverter noise source requires the double Fourier integral technique because its switching cycle and the fundamental cycle are in two different time scales. The noise path requires parasitic parameter extraction through finite element analysis for complex-structured power bus bar and printed circuit layout. After inverter noise source and path are identified, the effects of different modulation schemes on EMI spectrum are evaluated through the proposed frequency-domain analysis technique and verified by hardware experiment. The results, again, demonstrate that the proposed frequency-domain analysis technique is valid and is considered a promising approach to effectively predicting the EMI spectrum up to tens of MHz range.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Electrical and Computer Engineering

Department dc:contributor.department

Electrical and Computer Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2004

Author dc:creator

• Huang, Xudong

Chair dc:contributor.committeechair

• Lai, Jih-Sheng

Committee members dc:contributor.committeemember

• Nelson, Douglas J.
• Lu, Guo-Quan
• Liu, Yilu
• van Wyk, Jacobus Daniel

• frequency domain
• electromagnetic interference (EMI)
• differential mode (DM)
• common mode (CM)

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-10012004-145511

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/29157