This paper is focused on a general design principle of a uniform step multilevel converter, with K series-connected full bridges inverters per phase. A new design terminology is proposed and analytical relationships are established. The DC-voltage sources supplying partial inverters are supposed to be rationally unbalanced. The corresponding “Asymmetrical” topology provides more flexibility to the designer, and can generate a large number of levels (any odd number from 2K+1 to 3K) without increasing the number of H-bridges. Simulation results and experimental tests shown the reliability of the design approach suggested.