Control apparatus for an electric car
In an electric car, wherein the powering drive and the braking drive are executed by on-off controlling a current through a dc motor by means of a chopper, when the electric car is below a predetermined speed, a field coil of the dc motor is put into a series winding connection so as to carry out full field control, and when the car is above the predetermined speed, the field coil of the dc motor is changed-over to a shunt winding connection so as to carry out weak field control. The duty cycle of the chopper is controlled with the running state of the electric car taken into consideration in order that the field current at the time when the series winding connection has been changed-over to the shunt winding connection may become substantially equal to a value before the change-over, whereby the transient change of the current between before and after the change-over of the field coil is suppressed.
- Assignee:
- Hitachi, Ltd.
- Patent Number(s):
- US 4171506
- OSTI ID:
- 5777878
- Country of Publication:
- United States
- Language:
- English
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