中文摘要：

分析了输入侧断相对使用升压型三角形联结自耦变压器的12脉波整流器的影响，给出正常工作和断相运行时整流器各处的电压和电流特征。理论分析和实验结果表明，两整流桥输出电压的瞬时差是形成12脉波整流的关键；断相时，12脉波整流器等效为两个具有相同输入电压的单相全桥整流电路的并联，两整流桥输出电压瞬时差等于零，导致负载电压为2脉波，直流侧电能质量显著降低；所断相的输入电流等于零，整流器工作于严重的不对称状态。

英文摘要：

The effect of open-phase on 12-pulse rectifier using step-up delta-connected autotransformer was analyzed, and the voltage and current characteristic of 12-pulse rectifier under normal operation and open phasing were presented, respectively. Theoretical analysis and experimental results show that the in- stantaneous difference of the two bridge rectifiers＇ output voltages is the key point of realizing 12-pulse rectification. After open phase, the 12-pulse rectifier is equivalent to be two single-phase rectifiers with the equal input voltages which means that the instantaneous voltage difference is zero, causes the load voltage to be 2 pules, and depresses the power quality of DC side. Input line current of the phase under open phase is zero, which causes the rectifier operates to be at asymmetrical condition. The results pro- vide the basis of analysis and real time processing for parallel-connected 12-pulse rectifier under open- phase.