| 摘要 |
PROBLEM TO BE SOLVED: To prevent the overvoltage of a DC voltage feeding device by changing the acceleration/deceleration rate of an AC variable speed drive, unit, and to reduce the capacity on the regeneration side by effectively using the small regenerative capacity. SOLUTION: When each AC variable speed drive unit 6 performs the regenerative action, the DC bus voltage of a DC voltage feeding device 1 is boosted. When the voltage is boosted over the overvoltage detection standard value, the AC variable speed drive unit 6 reduces the acceleration/deceleration rate, based on the prescribed reduction ratio. The optimum operation can be achieved in the range not exceeding the capacity of the regenerative side. The small regenerative capacity can be effectively used by selecting the operation with the overvoltage surplus as the reduction ratio of the acceleration/deceleration rate by a selection circuit 4. By reducing the deceleration rate, the overvoltage of the DC voltage feeding device can be prevented and the capacity on the regenerative side can be reduced. |
