| 摘要 |
PURPOSE:To drive the same load by a plurality of voltage type inverter devices and an induction motor by decreasing the output voltage of an inverter upon increasing of a load current of an induction motor, reducing the output torque of the motor and applying a drooping characteristic. CONSTITUTION:An alternating current which is supplied from a 3-phase AC power source 1 is converted by a converter 2 into a direct current, and an induction motor 5 is driven by an inverter 4. On the other hand, the output of a frequency setter 6 is supplied through an acceleration/deceleration limiter 7 to a voltage/frequency converter 8 and a voltage controller 9. The output of the converter 8 is converted by a ring counter 10 into a pulse train signal, the output of the controller 9 is compared by a comparator 11 with the output of a triangular wave generator 12. The modulation output of a modulator 13 controls the inverter 4 via a distributor 14 and a base drive circuit 15. The load current of the motor 5 is detected by a current transformer 16, converted into a direct current by a current detector 17 and applied to the controller 9. In this manner, when the load current is flowed, the output of the controller 9 is reduced to add the drooping characteristic to the output of the motor. |
