Patent ID: 7577008

Claim:
A converter circuit, comprising at least one phase module having two serially connected converter valves, each converter valve comprising: at least one two-terminal subsystem having a first pair of turn-off semiconductor switches connected in series at a first connection point to form a first connecting terminal of the subsystem, and a second pair of turn-off semiconductor switches connected in series at a second connection point to form a second connecting terminal of the subsystem; four diodes connected antiparallel with the turn-off semiconductor switches in one-to-one correspondence, with the first and second pair of the turn-off semiconductor switches being connected in series at a third connection point defining a reference potential; a first unipolar storage capacitor connected in parallel with the first pair of the turn-off semiconductor switches; a second unipolar storage capacitor connected in parallel with the second pair of the turn-off semiconductor switches; and an electronic circuit connected to the reference potential, said electronic circuit operating the turn-off semiconductor switches.