A converter converting between a dc voltage at a first voltage level and at least one waveshape at a second higher voltage level has a primary connection port for the dc voltage, one secondary connection port for each waveshape, and one stack of cells for each secondary port. Each stack includes n cells connected in cascade between the primary port and the corresponding secondary port. At least (n−1) of the cells in a stack have: first, second, third, and fourth terminals, a first energy storage, and first, second, and third switches, where the first energy storage is connected in parallel with the first and second switches, the first terminal is provided at a junction between the first energy storage and the first switch, and the second terminal is provided at a junction between the first energy storage element, the second switch and the third switch.