Although the traditional passive tap inter-phase converter can reduce the total harmonic distortion rate of the grid-side current of the 12-pulse rectifier system, the high loss caused by the series connection between the tap and the load circuit seriously restricts the application of this method in high-power rectifiers. For this reason, a passive harmonic suppression scheme with low loss and easy to implement is proposed. In this scheme, only two double-tap inter-phase converters with symmetrical structure are arranged on the DC side of the 12-pulse rectifier. The square wave current generated by the auxiliary diode modulation principle is used to increase the pulse number of the rectifier from 12 to 24. Compared with the passive double-tap inter-phase converter, the proposed scheme reduces the effective value of auxiliary diode current to 2% while achieving the same harmonic suppression effect. The proposed scheme has strong robustness, low loss and is easy to implement, and so it is more suitable for low voltage and high current applications.

This work is supported by the National Natural Science Foundation of China (No. 52067013 and No. 51867012).