| As the non-linear nature of the uncontrolled rectifier, which has been widely used in the power supply equipments, the input line currents have significant harmonics and high total harmonic distortion (THD). When the power of the equipments is higher, the harmonics in the utility interface are larger. At the high power applications, the multi-pulse rectifier has been used to eliminate the certain harmonics, shape the input current, and reduce the harmonics pollution to the utility. The schemes of the present typical multi-rectifiers are given with the detailed conceptions and analysis, on emphasis of the use of autotransformer. The relationship between the number of the rectifier pulse and the order of the harmonics is concluded. The 24-pulse rectifier based on autotransformer scheme is proposed in the paper. This circuit is verified in rigorous theory and analyzed in details in the aspects of autotransformer connection, input current, interphase reactors, and KVA rating of the autotransformer. Proved in mathematics, the proposed circuit can eliminate the 5th,7th,11th,13th,17th,19th etc harmonics, and reduce the THD greatly. The simulated waveforms are given on the software Synopsys Saber. Then an experimental installation is given .The parameters of the autotransformer and the interphase reactors are designed. Finally, the experimental waveforms and results are given. In conclusion, the correctness and feasibility of the proposed 24-pulse rectifier based on autotransformer circuit is verified by the mathematical analysis, simulation research and experiments validation.
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