A voltage balancing strategy with extended operating region for cascaded H-bridge converters

Morteza Moosavi, Ghias Farivar, Hossein Iman-Eini, Seyed Mohammad Shekarabi
2014 IEEE transactions on power electronics  
In this paper, a generalized switching technique for cascaded H -bridge (CHB) converters is proposed. To take advantage of both low-and high-frequency modulation techniques, a hybrid modulation method is utilized. The proposed technique employs the low-frequency switching for voltage balancing of the dc-link capacitors, and the high-frequency sinusoidal pulse-width modulation switching for shaping the input ac current. Using the proposed technique, the stable operating region of CHB converters
more » ... of CHB converters is extended. The proposed technique is capable of maintaining the dc voltages balanced even under critical operating conditions in which the load of one H -bridge cell is removed. The validity and effectiveness of the proposed method is confirmed by several simulation and experimental tests on a seven-level CHB rectifier. Index Terms-Active rectifier, cascaded H -bridge (CHB) converter, multilevel converter, voltage balancing.
doi:10.1109/tpel.2013.2286270 fatcat:oqnfi5xxl5ab7kd6iy7urusqu4