| 摘要 |
<p>PURPOSE:To keep a filter capacitor voltage in constant and to shorten a dead time by connecting an overvoltage protective circuit composed of a series circuit of a resistance and a thyristor having a power of self-extinction of arc in parallel with the filter capacitor. CONSTITUTION:If an electrically incomplete contact on a sliding face occurs at an S point of time, a voltage of filter capacitor FC abruptly decreases and a converter CONV stops at an A point of time. Then, if a pantagraph Pan again contacts an aerial line at a B-point of time, the voltage is increased by an LC circuit of a filter reactor FL and a filter capacitor FC. At a C-point of time, an overvoltage detector VD is operated, a thyristor Th1 having a power of self-extinction of arc is ignited and a voltage of the filter capacitor FC is suppressed. Then, the thyristor Th1 is controlled by chopping to keep a voltage of the filter capacitor in constant. Then, the converter CONV returns to operation from a D-point of time.</p> |
