Space vector modulation for multilevel single-phase cascade converters avoiding the negative effects of the DC voltage unbalance

Modulation techniques for multilevel converters can create distorted output voltages and currents if the DC link voltages are unbalance. This situation can be avoided if the instantaneous DC voltage error is taken into account in the modulation process. This paper proposes a feed-forward space vector modulation method for single-phase multilevel cascade converters. Using this modulation technique, the modulated output voltage of the power converter always generates the reference determined by the controller even in voltage worst voltage unbalanced conditions. Experimental results from a 5 kVA prototype are presented in order to validate the proposed modulation technique.