A MULTIPHASE TRANSFORMER RECTIFIER UNIT

摘要

The object of the present invention is to provide an inventive multiphase transformer rectifier unit (1) for converting a three-phase (R, S, T) alternating current (AC) supplied from a power distribution system (2) to direct current (DC) supplied to at least one load (3). The multiphase transformer rectifier unit (1) comprises a magnetic core (5) having a primary winding set (17) and secondary winding set (18), and a rectifier circuit (22). The secondary winding set (18) is arranged to generate N substantially equally distributed output phases, wherein N is an odd number multiple of 3, and N > 3, and the primary winding set (17) is arranged to provide a positive or negative phase shift equal substantially to 360/(8x N) degrees of said output phases. By connecting two such multiphase transformer rectifier units (1) to the three- phase power distribution system, one thereof with changed order of connection of the input phases, the number of output pulses from the combination of two multiphase transformer rectifier units (1) will appear as doubled compared with a single inventive multiphase transformer rectifier unit (1) due to interleaved pulses from the two multiphase transformer rectifier units (1), thus reducing current distortion. It is also the object of the present invention to provide a corresponding inventive method of an arrangement of two inventive multiphase transformer rectifier units (1) for reducing current distortion in the power distribution system (2).