| 摘要 |
Method and apparatus for the operation of a direct current (d.c.) motor requiring no start-up resistor and accompanying switches. Regenerative braking is obtained and the torque interference in the operation is carried over to the electrical input after being dampened, due to the "soft" speed/torque characteristic. The d.c. motor is directly controlled by a technique which stimulates either the characteristics of a shunt-wound motor or a series-wound motor. A command signal is provided by an adjustable signal source which is adjusted in accordance with the armature current desired. A d.c. voltage source is controlled to provide an armature current in accordance with the command signal. When the armature voltage reaches its nominal value, a controlled d.c. current source is regulated in accordance with an error signal which is the difference between the command signal and the armature current, to regulate the excitation. The armature current/armature voltage control is thereby switched to an armature current/excitation control under which control the d.c. motor follows the "soft" speed/torque characteristic curve. To achieve braking, the command signal is reversed. This condition is detected by the differential unit to initiate braking. By maintaining the given nominal load current in accordance with the command signal setting of the signal source, motor speed decreases until the excitation reaches its nominal value. This condition is detected, causing the armature current/excitation control to be switched back to the armature current/armature voltage control. With decreasing speed, armature voltage is reduced in value until the d.c. motor stops. |
