| 摘要 |
PURPOSE:To prevent the occurrence of an offset by providing a function generating means which generates a field magnetic flux command in accordance with the speed of a motor and controlling a field magnetic flux by using the sum of the output signal of an armature current controlling means and the field magnetic flux command. CONSTITUTION:The torque and speed omega of a motor increases or decreases when an armature current Ia increases or decreases due to a change Ec in armature-induced voltage following a change If in a field current. As the speed omega increases or decreases, a function generator 41 increases or decreases a field magnetic field command If1 and makes compensating operations so as to offset the change in armature induced voltage. Because of the compensating operations, the output signal Ifc of an armature current controlling amplifier 19 becomes a nearly stable value, since the signal Ifc is not required to compensate the variation of the armature current affected by a change in induced voltage caused by a speed change. Therefore, even when ordinary PID control is used for the amplifier 19, no current standard deviation occurs and the occurrence of an offset can be eliminated. |
