Directly stopping elevator system and its control method

Abstract

The elevator system includes programmable logic controller, frequency converter, motor, encoder, cage lift wall and various switch signals. The frequency converter controlled motor drives the elevator cage to move up and down; the programmable logic controller controls the elevator via the detection of various lift wall, storey station and cage signals; the programmable logic controller controls the start and stop of the frequency converter via the connecting wires to the frequency converter, makes the frequency converter obtain accurate remainder distance information for the real-time correction of the elevator deceleration curve, accurate storey leveling, high elevator efficiency and comfortability.

Description

technical field [0001] The present invention relates to an elevator system, in particular to a direct-stop elevator system and a control method thereof. Background technique [0002] In existing elevators, a programmable logic controller (ie PLC) and a frequency converter are used as the control system. In this system, the PLC realizes the control and management of the elevator by detecting the states of the hoistway and the car, and controls the start and stop of the frequency converter according to these detection signals. The frequency converter generates a speed curve, and drives the motor to make the elevator car move up and down according to the predetermined running curve. [0003] In this system, PLC can perform such as elevator safety monitoring, hoistway signal detection, car command, landing call signal detection, maintenance, and confirmation of automatic running status. After processing various signals, the inverter can be started or stopped through the input ...

AI Technical Summary

Problems solved by technology

[0007] But this creates other problems for the elevator

Because Figure 4 In the situation where the leveling switches 7 and 8 are activated at T3, in order to make the leveling accurate and the brake acceleration not too large, the stop distance S2 should not be too large, generally between 5-8mm, so the setting of the crawling speed V1 not too high

This will cause the elevator to vibrate to a certain extent when the elevator is crawling due to the low-speed characteristics of the motor, which will cause passengers to feel uncomfortable.

In addition, due to the measurement error of the car position detection caused by the PLC execution cycle, the actual remaining distance of the deceleration point issued by the PLC is smaller than the required deceleration distance, and the elevator may exceed the leveling position and reverse the leveling. Therefore, the PLC must be forced to issue a deceleration in advance. In this way, the inverter drives the motor to decelerate in advance without causing the elevator to run too far, which will lengthen the crawling distance, increase the crawling time, and reduce the operating efficiency of the elevator.

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