Computed PWM for flying capacitor multicell converters

In the literature, flying capacitor converters have been mainly presented with a phase-shifted carrier modulator. However, due to the low switching frequency of high voltage IGBTs off-line optimization of the control pattern may be desired. This paper shows how this question can be addressed. As a first stage, a way to optimize a multilevel waveform is described; the results obtained at this stage are general and can be used for single or three-phase converters, for any topology of multilevel converter and any number of levels. Then it is shown how these results can be applied to flying capacitor multicell converters and in particular how the flying capacitor voltages can be regulated.