| 摘要 |
PURPOSE:To achieve a sudden acceleration and deceleration by a method wherein the ratio is kept constant of the motor voltage against the motor frequency. CONSTITUTION:The output of a voltage controlled amplifier 10 is of the negative polarity when on power running and of the positive polarity under braking, and the polarity is discriminated by a torque direction detecting circuit 21. Power running causes the torque direction detecting circuit 21 to yield a signal to place the braking current controlled amplifier 15 in a stop status, which in turn causes a braking phase controlled circuit 16 to output a signal to turn off a switching device 19. Application of brake causes the torque direction detecting circuit 21 to output a signal placing the braking current controlled amplifier 15 and the braking phase controlled circuit 16 in an operating status. Regenerative run causes the output of the voltage controlled amplofier 10 to be compared with the braking current coming through the braking current detecting detector 18 and then inputted to the braking current controlled amplifier 15. The output of the braking current controlled amplifier 15 is inputted to the braking phase controlled amplifier 16 yielding a signal in response to which the switching device 19 is chopped. |
