三相桥式半控整流电路失控分析及其抑制策略研究

中小型汽轮发电机组励磁系统中常采用三相桥式半控整流电路输出电压作为励磁电源,但三相桥式半控易发生失控现象,影响发电机组正常运行。文章深入研究三相桥式半控整流电路失控产生的原因,并分析触发脉冲丢失情况下电路失控后的运行状态。针对已有并联续流二极管抑制失控的方法,提出一种并联续流二极管加并联阻容元件的方法,以及保证晶闸管可靠关断的改进电路。通过MATLAB/Simulink仿真验证了该方法的可行性和有效性,为提高发电机组运行稳定性提供了理论支撑。

Analysis on the runaway of three-phase bridge half-controlled rectifier circuit and its suppression measure

The output voltage of the three-phase bridge half-controlled rectifier circuit is often used as the exciting voltage in the excitation system of small and medium-sized turbo-generator sets. However, it is easy to be out of control and affect the normal operation of generator set. In this paper, the causes of the runaway of the three-phase bridge half-controlled rectifier circuit are studied in depth, and the operation state of the circuit after the runaway under the loss of the firing pulse is analyzed. Based on a suppression method with a parallel freewheeling diode, an improved circuit with parallel resistance and capacitance is proposed to ensure the reliability turn-off of the thyristor. Finally, the simulation experiment based on Matlab/Simulink verifies the feasibility so as to provide theoretical support for improving the operation stability of generator set.