Spectral analysis of multilevel PWM strategies using a one-dimensional fourier series

This paper presents a novel spectral analysis technique for multilevel modulation. Conventionally, such analyses use a Double Fourier series technique, but this approach can become intractable when complex reference waveforms (e.g. multilevel space vector offsets) and regular sampling processes are considered. In contrast, the strategy proposed in this paper separates the multilevel pulse width modulation (PWM) waveform into a spectral image of the reference, and sideband basis functions which are then expanded using a one-dimensional Fourier series. The approach enables previously intractable PWM problems to be solved. Results of this analysis are validated against previously published multilevel inverter Double Fourier series results.