| 摘要 |
<p>An electric vehicle traction motor control circuit includes an armature current control and a separate field current control. The armature current control includes an armature current demand signal generator, a difference amplifier comparing the demand signal with a signal from an armature current transducer. This amplifier drives an armature current switching regulator including a Schmitt trigger. The field current control is arranged to provide a fixed field current normally, which is weakened when the actual armature current fails to reach its demand value. The field current control thus includes a start up circuit connected to the output of the Schmitt trigger and arranged to operate, when the Schmitt trigger output has been in a first state for more than a predetermined duration, to connect the output of the first difference amplifier to the input of a further difference amplifier to weaken the field current in accordance with the difference between the output of the first difference amplifier and a reference level.</p> |
