| 摘要 |
PURPOSE:To increase the regenerative region by connecting a semiconductor switch in parallel with a brake series resistor to perform a chopping operation, thereby smoothly shortcircuiting the resistor. CONSTITUTION:A gate turn-off thyristor (GTO) 12 is turned OFF in a range from a point A to a point B to insert a brake series resistor 10 at regeneratively braking time, and the conduction rate of a chopper 6 is controlled so that the voltage of a series unit of an armature winding 9 and the resistor 10 becomes constant. The GTO12 is chopped in a range of the point B to a point C while the conduction rate of the chopper 6 is held minimum, and a motor current IM is controlled to become equal to a command value I0 by gradually increasing the conduction rate. Thus, the regenerative power increases, and the shortcircuit of the resistor can be smoothly performed. |
