A new DC voltage balancing method for cascaded multilevel inverter based STATCOM

It has been mentioned in the literature that, among the multilevel inverter topologies used for STATCOM applications, the cascaded multilevel topology is the most advantageous and economical one. On the other hand, the main problem of this topology comes out to be the difficulty of sustaining the DC capacitors´ mean voltages. This issue is very important for obtaining an output voltage with low THD and having equal device stresses. In this work, a new DC voltage balancing method (Selective- Swapping Algorithm) for cascaded multilevel inverter based STATCOM applications is investigated and the results are given. Moreover, these results are compared with the ones obtained for the other DC voltage equalization methods given in the literature.