Active power balance in cascaded multilevel converter under bipolar and unipolar modulation

Multilevel converters have turned into a mature technology that has helped their use in high power applications. This paper presents the performance comparison of the active power imbalance in the cells of a cascaded H-bridge (CHB) multilevel converter under bipolar and unipolar modulation based converter control. This paper also analyses the condition of power balance and imbalance across each cells of the CHB. The advantage of unipolar modulation scheme over bipolar modulation scheme is shown in terms of the current tracking performance. The simulation studies are performed in the PSCAD/EMTDC software and the experimental results have been obtained for further validation of the presented work.