| 摘要 |
PURPOSE:To suppress the variation in a DC bus voltage to the minimum limit when an operating mode is shifted by generating an operating mode conversion acceleration signal when the operating mode is shifted, and shifting the operating mode of a converter. CONSTITUTION:When the part of induction motors which are operated at the aligned speed are shifted to a regenerator operation, a DC bus voltage Vd starts rising, a power drive generative conversion detector 11 outputs to close a switch 12. Accordingly, an operating mode conversion acceleration signal P is applied in the same polarity as the output of a DC voltage detector 7 to a butting point. Since the signal P has considerably large level, the input of a voltage controller 9 becomes a large regeneration command input, a converter 2 is shifted rapidly to the regenerative operation, and the rise of the voltage Vdc is accordingly suppressed, and the variation in the speeds of induction motor IM group which are not operated at the aligned speed. |
