UPS system capable of reducing input harmonic waves

The invention discloses a UPS (Uninterrupted Power Supply) system capable of reducing input harmonic waves, which comprises N UPS modules and a transformation module, N is not less than two, the transformation module comprises a plurality of transformer units, a primary side winding of each transformer unit is of a triangular connection structure and is used for being connected with a power supply, and a secondary side winding of each transformer unit is of a triangular connection structure. The secondary side windings of each transformer unit are connected with the input ends of the UPS module in a one-to-one correspondence manner; the plurality of transformer units are respectively a first input transformer, a second input transformer, X third input transformers and Y fourth input transformers, a secondary side winding of the first input transformer is of a triangular connection structure, and a secondary side winding of the second input transformer is of a star connection structure; a secondary side windin