| 摘要 |
PURPOSE:To stop the vibrating current of a main circuit motor by adding the differentiated factor of an induction motor current to a slip frequency at the power drive time and subtracting it at the regeneratively braking time. CONSTITUTION:The differentiated factor FS3 is added to the sum of a reference slip frequency FS1 and a constant current correction slip frequency FS2 via a switch 15 at the power running time by the differentiating compensator 14 of a current IM of an induction motor. Thus, even if a vibrating current is generated at the current IM of the motor, the current of the exciting inductance is maintained constant, and large damping is operated only for the vibrating current. In case of the power regenerative brake, the power is reversely returned to the power source. Accordingly, the variation in the current IM of the motor becomes in phase with variation in the voltage of an input filter capacitor, and the differentiating factor of the current IM of the motor is accordingly added to the negative feedback, thereby obtaining entirely the same damping effect as the case of power running. |
