JPH0336992A - Speed controller of inverter for elevator - Google Patents

Abstract

PURPOSE:To reduce abrupt speed change, vibration of an elevator by processing to primarily delay a load torque detection value in a speed controller for detecting plural times a load change component as a load torque to correct plural times the operating frequency and voltage of an inverter. CONSTITUTION:An operating speed of an induction motor 5 is controlled by a controller 6 and a slip calculator 7. The calculator 7 has a current detector 8, a current/torque converter 10, a filter circuit 11, and a torque/slip converter 12. The DC current of an inverter main circuit is detected plural times during one operating period of an elevator by the detector 8. A torque current of the motor 5 is obtained from the detection value by the converter 10. A primary delay calculation is conducted by the circuit 11 at the torque current. Accordingly, the abrupt change of the output of the converter 12 is suppressed to alleviate the vibration, shock of riding in a cage.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a speed control device for an induction motor using an elevator inverter, and more particularly to a speed control device for correcting changes in load torque in open loop control.

B1 Summary of the Invention The present invention provides a speed control device that controls the speed of an induction motor by open-loop control of an inverter, and corrects the operating frequency and voltage of the inverter by detecting load changes as load j·lux multiple times. By applying first-order delay processing to the elevator load torque detection, it is possible to reduce sudden changes in speed and vibration due to errors in load torque detection or changes due to noise, and improve landing accuracy.

C1 Prior Art Most recent elevators employ an induction motor as a prime mover, and this induction motor is driven by a variable voltage/variable frequency (VVVF) inverter. In such an elevator drive system that combines an induction motor and an inverter, the speed control of the induction motor is generally used for low-speed elevators; open-loop control using a voltage-type inverter is used for medium- and high-speed elevators, and speed detection is used for medium and high-speed elevators. Speed feedback control with a built-in device is adopted.

Among these, the open-loop speed control method controls the output frequency and output voltage of the inverter according to the speed pattern, thereby achieving acceleration that matches the speed pattern.
Try to obtain constant speed and deceleration. This control method eliminates the need for a speed detector, resulting in lower costs, and also eliminates the need for backup means in case of a failure in the speed detection system. Since the vehicle does not have a speed detection system to control the load, load fluctuations worsen landing li'.

Claims (1)

[Claims] (1) The speed of the induction motor is controlled by an open-loop control inverter, and the load change of the induction motor is detected multiple times as load torque from the inverter's DC current detection value, and the operating frequency and voltage of the inverter are corrected multiple times. A speed control device for an elevator inverter, comprising a filter circuit that performs first-order delay processing on the detected load torque value with a time constant larger than the time until the next detection/correction. Control device.