Title :
High-bandwidth, high-fidelity in-circuit measurement of power electronic switching waveforms for EMI generation analysis
Author :
Oswald, Niall ; Stark, Bernard H. ; McNeill, Neville ; Holliday, Derrick
Author_Institution :
Dept. of Electr. & Electron. Eng., Univ. of Bristol, Bristol, UK
Abstract :
The useful bandwidth of power electronic switching waveform measurements is limited by the finite resolution of measurement instrumentation and the spectral characteristics of switching waveforms, which exhibit a steep roll-off with increasing frequency. This limits the use of such measurements in EMI generation analysis, simulation and prediction. A method combining PC-based offline data processing and high-pass filtering of the waveforms prior to measurement allows the useful measurement bandwidth to be extended to 100 MHz in the case of a 1200 V, 15 A IGBT operating under realistic conditions. When utilised with commercially available current probes and passive voltage probes, this method offers high-fidelity measurements. However, it is more difficult to obtain repeatable measurements with high-voltage differential probes. The resulting spectra of IGBT collector-emitter voltage and collector current waveforms are presented; the increased bandwidth allows the high-frequency spectral gradient of -60 dB/decade to be observed across the 30-100 MHz band most critical for radiated EMI generation in IGBT-based power converters. The effect of series gate resistance variation is thus apparent, and spectral evidence is provided for the 30-100 MHz band being dominated by the turn-on transients with small gate resistances, and by the turn-off transients with large gate resistances.
Keywords :
electromagnetic interference; high-pass filters; insulated gate bipolar transistors; interference suppression; power system measurement; spectral analysis; switching convertors; EMI generation analysis; IGBT collector emitter voltage; PC based offline data processing; collector current waveforms; current probes; differential probes; frequency 30 MHz to 100 MHz; high-pass filter; in-circuit measurement; passive voltage probes; power converters; power electronic switching waveforms; power measurement; spectral analysis; Bandwidth; Current measurement; Frequency measurement; Insulated gate bipolar transistors; Noise measurement; Probes; Voltage measurement;
Conference_Titel :
Energy Conversion Congress and Exposition (ECCE), 2011 IEEE
Conference_Location :
Phoenix, AZ
Print_ISBN :
978-1-4577-0542-7
DOI :
10.1109/ECCE.2011.6064297