A power converter, comprising: a first bus, being a positive direct current bus; a second bus, being a negative direct current bus; and at least one leg operatively coupled between the first bus and the second bus, the at least one leg comprising: a first string comprising: a first branch including a plurality of controllable semiconductor switches and a first connecting node being situated between two of the controllable semiconductor switches, and a second branch including a plurality of controllable semiconductor switches and a second connecting node being situated between two of the controllable semiconductor switches, the second branch being operatively coupled to the first branch via a third connecting node operatively coupled to a third bus; and a second string operatively coupled to the first string via the first connecting node and the second connecting node, wherein the second string comprises a first portion including a plurality of switching units, and a second portion including a plurality of switching units; wherein each switching unit includes a plurality of fully controllable semiconductor switches (402, 404) and at least one energy storage device; and the power converter being characterized in that the third bus is a middle or centre direct current bus and the first and second portions (320, 322) of the second string are operatively coupled to a fourth bus or phase, preferably being an alternating current bus or phase. a first bus, being a positive direct current bus; a second bus, being a negative direct current bus; and at least one leg operatively coupled between the first bus and the second bus, the at least one leg comprising: a first string comprising: a first branch including a plurality of controllable semiconductor switches and a first connecting node being situated between two of the controllable semiconductor switches, and a second branch including a plurality of controllable semiconductor switches and a second connecting node being situated between two of the controllable semiconductor switches, the second branch being operatively coupled to the first branch via a third connecting node operatively coupled to a third bus; and a second string operatively coupled to the first string via the first connecting node and the second connecting node, wherein the second string comprises a first portion including a plurality of switching units, and a second portion including a plurality of switching units; a first string comprising: a first branch including a plurality of controllable semiconductor switches and a first connecting node being situated between two of the controllable semiconductor switches, and a second branch including a plurality of controllable semiconductor switches and a second connecting node being situated between two of the controllable semiconductor switches, the second branch being operatively coupled to the first branch via a third connecting node operatively coupled to a third bus; and a first branch including a plurality of controllable semiconductor switches and a first connecting node being situated between two of the controllable semiconductor switches, and a second branch including a plurality of controllable semiconductor switches and a second connecting node being situated between two of the controllable semiconductor switches, the second branch being operatively coupled to the first branch via a third connecting node operatively coupled to a third bus; and a second string operatively coupled to the first string via the first connecting node and the second connecting node, wherein the second string comprises a first portion including a plurality of switching units, and a second portion including a plurality of switching units; a first portion including a plurality of switching units, and a second portion including a plurality of switching units;