Charging of split DC links of a converter system

A converter system comprises two phase modules, each phase module comprising a first converter leg and a second converter leg interconnected with a DC link, and a charging transformer for charging the DC link. The DC link comprises two capacitors connected in series between a positive point, a middle point and a negative point, each converter leg adapted for interconnecting an output with the positive point, the middle point or the negative point of the DC link. The phase modules are connected in series via outputs of the converter legs, such that a second converter leg of a lower phase module is connected with a first converter leg of a higher phase module. The charging transformer is connected to the middle point of the DC link of a highest phase module, which provides a phase output of the converter system with an output of a second converter leg. The converter system includes two converter phases, each converter phase comprising at least two series connected phase modules. At a star point of the converter phases the converter phases are star-connected via outputs of first converter legs of lowest converter modules, which are series connected with higher converter modules, whereby a module side start point of the charging transformer is connected or is not connected with the star point of the converter phases.