New configuration of stacked multicell converter with reduced number of dc voltage sources

Multicell converters are a very interesting alternative for medium voltage and high power applications. The two most significant types of multicell converters based on flying capacitors are flying capacitor multicell and its derivative stacked multicell converters. This paper presents a new configuration of stacked multicell converter. The main advantage of the proposed converter, in comparison with conventional stacked multicell converter, is that the number of required dc voltage sources is reduced from two to one. This progress is achieved by connecting the upper stack to lower stack while the number of high frequency switches and capacitors, voltage ratings of capacitors and switches and the number of high frequency switchings during a full cycle are kept constant. This converter is controlled by a phase shifted sinusoidal pulse width modulation; so, the self balancing property of the stacked multicell converter is maintained in the proposed converter. The circuit is simulated using PSCAD/EMTDC software and simulation results are presented to validate the effectiveness and advantages of the proposed configuration as well as its control strategy. (6 pages)