A Series-Connected 24-Pulse Star Rectifier Employing Two Different Pulse-Doubling Interphase Reactors

A simple, series-connected, 24-pulse star rectifier employing two different pulse-doubling interphase reactors (PD-IPRs) is proposed in this work. The proposed topology consists of two double-star rectifiers, a parallel-connected PD-IPR and a series-connected PD-IPR. The comodulation of the two PD-IPRs in the rectifier doubles the pulse number of each double-star rectifier and provides a phase displacement of 15° for the two sets of double-star rectifiers. The pulse number of the rectifier is increased from 6 to 24 by the two rectifiers connected in series. The resulting 24-pulse rectifier draws near-sinusoidal input line currents with 4.2% total harmonic distortion. The two small-capacity PD-IPRs can perform phase shifting, thus avoiding the use of complex phase-shifting transformers. The proposed rectifier has a simple structure, easy implementation and low cost. An experimental prototype with an output power of 3.1 kW is constructed to verify the correctness of the theoretical analysis.