Static converter with electric valves comprising a twelve-phase connection with two Graetz bridges for the suppression of harmonics 5 and 7 of network current

Claim 1

An alternating to direct current static converter including a polyphase rectifier system comprising: a three-phase transformer having a primary winding with three-phase inputs and a secondary winding with three-phase outputs, said three-phase transformer being constructed and arranged to have predetermined winding connection and phase angle displacement such that a 150 degree phase angle displacement occurs between voltages in each phase of said primary inputs and the corresponding phase of the secondary winding outputs; a first rectifier bridge having inputs coupled to associated ones of the phase inputs to said primary winding of said transformer and an output; a second rectifier bridge having inputs coupled to associated ones of the phase outputs of said secondary winding and an output; and means for coupling the outputs of said first and second rectifier bridges for providing a direct current output, said rectifier bridges being coupled to said three-phase transformer such that alternating voltages applied to the input terminals of said first rectifier bridge from the phase inputs to said primary winding are shifted 30 degrees from the voltages applied to the input terminals of the second rectifier bridge from the phase outputs of said secondary winding.