CONVERTER OF THREE-PHASE AC VOLTAGE INTO DC VOLTAGE Russian patent published in 2009 - IPC H02M7/162 

FIELD: electricity.

SUBSTANCE: present invention relates to converting techniques and can be used for converting three-phase ac voltage into dc voltage with a constant level of higher harmonics in the entire control range. The converter of three-phase ac voltage to dc voltage contains a zero input terminal, N (where N=1, 2, 3, …) three-phase controlled bridge rectifiers, pairs of paralleling reactors, pairs of extra diodes, two-terminal devices. Each terminal of the i^th (where i=1,2,3, …, N) bridge is connected to the outermost lead of the winding of the i^th pair of paralleling reactors, the other outermost lead of which is connected to the electrode of the i^th pair of extra diodes. The i^th extra diodes and rectifiers of the i^th bridge are connected to the outermost leads of the winding of the same paralleling reactor by similar electrodes. The common point of free electrodes of i^th extra diodes is connected to the input lead of the i^th two-terminal device. Between the common point of the output leads of N two-terminal devices and zero input lead there is primary coupling circuit. Intermediate leads of the windings of the i^th pair of paralleling reactors form short-circuited output leads of the i^th bridge. The three-phase transformer, the primary phase windings of which contain each of the N+1 leads, are connected by one group of outermost leads to the phase inputs of the leads. The i^th of the remaining N groups of leads are connected to input leads of the i^th bridge. The secondary winding is connected into a star with zero output and is connected by phase leads to the inputs of the secondary bridge rectifier with a free input lead, the poles of which form its output leads. Between the free input lead and the zero lead of the secondary winding a secondary coupling circuit is formed. An extra winding is connected into a broken delta. The primary coupling circuit is short-circuited, and the secondary coupling circuit contains the above mentioned winding which is connected into a broken delta, the number of turns of which is less than the number of turns on the secondary winding of the three-phase transformer. If N=1, the two-terminal device is short-circuited, and when N=2, 3, 4, … each two-terminal device contains a pair of antiparallel connected rectifiers, one of which can be controlled with the same direction of connection of electrodes relative the zero input lead.

EFFECT: widening operational properties of the converter, while maintaining constant level of harmonic content of rectified voltage and inverse relationship between amplitude of higher harmonics of input current from firing angle of thyristors.

6 cl, 12 dwg