| 摘要 |
PURPOSE:To enable the size of a cooling device to be minimized, by a method wherein, in an electric railroad d.c. feeder circuit, plural series circuits of a self-arc-suppressing type semiconductor switches and resistors are arranged in parallel, and at least on or more circuits form a current continuous varying type. CONSTITUTION:The range of voltage from a d.c. feeder wire voltage starting level V1 to a rated voltage VRAT detected by a voltage detector 6 is about equally divided. By means of set detecting levels V2-Vn, a chopper part 14 compensates a regenerative current region, exceeding a control range ALPHAI, in which a current is capable of flowing continuously, by charging the stage of resistors 4-1-4-n of self-arc-suppression type semiconductor switches 3-1-3-n. A current value, being the regenerative current instruction value of a current reference setting circuit 21 less a stage control part current, forms the control current reference of a chopper control circuit 22 to control a regenerative current. This enables continuous varying of a regenerative current, and besides decreases a switching loss, and permits the size of a cooling device to be mini mized. |
