Abstract: A voltage source converter includes a number of converter modules, one for each of a number of phases, connected in-series between two DC terminals. Each converter module includes an upper director valve in series with a lower director valve, where a junction between the two provides a primary AC terminal, an upper wayshaper section, a common waveshaper block and a lower waveshaper section in parallel with the valves, where the upper and lower waveshaper sections include multilevel cells and the common waveshaper block include at least one common waveshaper connected between the upper and lower waveshaper sections, a first switching element connected between a secondary AC terminal and the upper waveshaper section and a second switching element connected between the secondary AC terminal and the lower waveshaper section.

Abstract: A voltage source converter includes a number of converter modules, one for each of a number of phases, connected in-series between two DC terminals. Each converter module includes an upper director valve in series with a lower director valve, where a junction between the two provides a primary AC terminal, an upper waveshaper section, a common waveshaper block and a lower waveshaper section in parallel with the valves, where the upper and lower waveshaper sections include multilevel cells and the common waveshaper block include at least one common waveshaper connected between the upper and lower waveshaper sections, a first switching element connected between a secondary AC terminal and the upper waveshaper section and a second switching element connected between the secondary AC terminal and the lower waveshaper section.