Harmonic reduction mechanism at DC link of two different 24-pulse rectifiers

In order to improve the ability of harmonic reduction at DC link of multi-pulse rectifier (MPR), the harmonic reduction mechanism at DC link of two kinds of 24-pulse rectifiers with double-tapped interphase reactor (IPR) or auxiliary single-phase full-wave rectifier (ASFR) was investigated. According to the configuration and Ampere-Turn balance with double-tapped IPR and single full wave rectifier, the function and operation mode of both rectifiers were analyzed. The effect of different operation mode on output currents of the two bridge rectifiers, input current of rectifiers, load voltage were also analyzed, and the theoretical values of turn ratios of both rectifiers were calculated. Theoretical analysis and simulation results show that because of the different operation mode of diodes between double-tapped IPR and ASFR, the modulating effect of currents and voltages of two bridge rectifiers is different. Therefore, the input currents and load voltages of both rectifiers are also different. In addition, under the optimal condition, both two 24-pulse rectifiers can reduce the 5th, 7th, 11th, 13th, 17th, and 19th harmonics, and depress the ripple coefficient of load voltage.