| 摘要 |
An electric vehicle traction motor control circuit includes a main thyristor in series with the motor armature between two supply rails. A second thyristor is connected in series with a commutating capacitor across the main thyristor which it can turn off by diverting the motor current briefly into the commutating capacitor. A third thyristor is connected in series with an inductor across the commutating capacitor and serves when fired, to reverse the voltage residing on the commutating capacitor following commutation. The second thyristor is connected to a pulse generator which is connected to be edge-triggered by the output of a comparator comparing actual motor current with upper and lower current limits set by a driver operable control. The comparator also brings an oscillator into operation which provides additional trigger inputs to the pulse generator if the latter fails to be edge-triggered by the comparator output. |
