Identification of the temporal source of frequency domain characteristics of SiC MOSFET based power converter waveforms

Certain Electromagnetic Interference (EMI) performance characteristics that occur in data taken from practical systems are often difficult to attribute to time domain features as waveforms will tend to deviate from the idealized analytical case. This paper shows that by taking multiple derivatives of experimental data and comparing this with the expected characteristics of a typical switching waveform it is possible to understand exactly which features of a given temporal waveform lead to certain spectral characteristics. It is also shown through analysis of analytical methods and experimental data that the smoother the transitions of a waveform the faster the roll off of the spectral content and hence the better the EMI performance.