Apparatus for power transmission

摘要

Apparatus for the transfer of electric power produced by at least one multi-phase alternating-current generator ( 1 ) or generator unit into at least one multi-phase alternating-current power network (U_u,U_v,U_w), said apparatus comprising at least one control unit ( 4 ), at least one non-controlled rectifier bridge ( 2 ), a direct-current intermediate circuit and at least one controlled inverter bridge ( 3 ) for supplying d.c. power into an alternating-current power network, said inverter bridge ( 3 ) having fully gate-controlled semiconductor switches (V 11 -V 16 ) in its upper and lower branches, and said control unit controlling the semiconductor switches (V 11 -V 16 ) of the inverter bridge ( 3 ) so as to cause them to conduct in such manner that: -in the upper branch, the switch in each phase conducts substantially as long as the instantaneous value of the network phase voltage (U_u,U_v,U_w) in question is the most positive, and -in the lower branch, correspondingly the switch in each phase conducts substantially as long as the instantaneous value of the network phase voltage (U_u,U_v,U_w) in question is the most negative. The rectifier bridge ( 2 ) is connected directly to the inverter bridge ( 3 ) without a d.c. capacitor unit functioning as an intermediate energy storage. In addition, the direct current output from the rectifier bridge ( 2 ) is conducted directly into those two a.c. network phases in which the magnitudes of the instantaneous values of the voltages are highest, without current limitation by an inductor unit.