| 摘要 |
PURPOSE:To improve the ride feeling of an elevator by applying the value produced by multiplying the differentiated value of a slip frequency command by a constant gain to a frequency command only when a current amplitude command is small, thereby improving the transient characteristic of a motor. CONSTITUTION:When an induction motor is shifted from a power drive to a regenerative brake or vice versa, a current amplitude command signal I becomes minimum. In such a case, a comparator 128 operates, the output of a differentiator 125A is outputted through a converter 129 to an adder 129, and the value produced by multiplying the differentiated value of a slip frequency command by a constant gain is applied to the frequency command. While the signal I is largely accelerating, the comparator 128 is not operated, and the output of the differentiator 125A is not inputted to an adder 126. |
