| 摘要 |
PROBLEM TO BE SOLVED: To make improvements in a speed control characteristic during the level compensating operation of an elevator by compensating a difference between the estimated load torque acting on the shaft of an AC motor and the load compensated torque by the output signal of a load detector into a torque current component. SOLUTION: In this elevator system which separates the current of an AC motor 606 into two parts, a torque current element and an exciting current element, thereby controlling a rotational speed in the AC motor, it is equipped with a speed detector 607 detecting a turning angle of the AC motor 606, a load torque estimator 618 estimating a load torque from the torque current element and speed of the AC motor 606, and a switch and an adder operating a difference between the load torque estimated from the load torque estimator 618 and a load compensated torque coming under the load capacity detected from a load detector 611, and adding this torque difference to the torque current element on the basis of a level compensation command, respectively. |
