CHARGING OF SPLIT DC LINKS OF A CONVERTER SYSTEM

A converter system (10) comprises at least two phase modules (18a, 18b), each phase module (18a, 18b) comprising a first converter leg (26a) and a second converter leg (26b) interconnected with a DC link (24), and a charging transformer (40) for charging the DC link (24). The DC link (24) comprises two capacitors (28a, 28b) connected in series between a positive point (30), a middle point (32) and a negative point (34), each converter leg (26a, 26b) being adapted for interconnecting an output (36a, 36b) with the positive point (30), the middle point (32) or the negative point (34) of the DC link (24). The phase modules (18a, 18b) are connected in series via outputs (36a, 36b) of the converter legs (18a, 18b), such that a second converter leg (36b) of a lower phase module (18a) is connected with a first converter leg (36a) of a higher phase module (18b). The charging transformer (40) is connected to the middle point (32) of the DC link (24) of a highest phase module (18b), which provides a phase output (U, V, W) of the converter system (10) with an output (36b) of a second converter leg (26b). The converter system (10) further comprises at least two converter phases (20), each converter phase (20) comprising at least two series connected phase modules (18a, 18b). At a star point (Y) of the converter phases (20) the converter phases (20) are star-connected via outputs (36a) of first converter legs (26a) of lowest converter modules (18a), which are series connected with higher converter modules (18b), whereby a module side star point (Υ') of the charging transformer (40) is connected or is not connected with the star point (Y) of the converter phases (20). L'invention concerne un système (10) de convertisseur comportant au moins deux modules (18a, 18b) de phase, chaque module (18a, 18b) de phase comportant une première branche (26a) de convertisseur et une deuxième branche (26b) de convertisseur interconnectées avec une liaison (24) à courant continu, et un transformateur (40) de charge servant à charger la liaison (24) à courant continu. La liaison (24) à courant continu comporte deux condensateurs (28a, 28b) reliés en série entre un point positif (30), un point médian (32) et un point négatif (34), chaque branche (26a, 26b) de convertisseur étant prévue pour interconnecter une sortie (36a, 36b) avec le point positif (30), le point médian (32) ou le point négatif (34) de la liaison (24) à courant continu. Les modules (18a, 18b) de phase sont reliés en série