| 摘要 |
PURPOSE:To prevent overcurrent tripping of an AC electric motor in an overcurrent state during power or regenerative operation and the speed reduction in an AC electric motor in advance. CONSTITUTION:When a positive peak current Idcp reaches an overcurrent state during power operation exceeding an allowable Idcpo, acceleration suppression control is performed where the increase in an output frequency is stopped the output frequency is increased until Idcp goes below Idcpo during acceleration control and deceleration promotion control is performed for reducing sliding in that the reduction ratio of the output frequency is increased until Idcp goes below Idcop during deceleration control. When the regeneration overcurrent state of the AC electric motor results, where the negative peak current Idcn exceeds the allowable value Idcno, acceleration promotion control for increasing the increase ratio of output frequency until Idcn goes below Idcno during acceleration control is performed and deceleration suppression control for decreasing and stopping or increasing the output frequency until Idcn goes below Idcno during deceleration control is performed, thus reducing negative sliding. |
