Escalator Three-Phase Motor Mode Control via Slip Rate Detection
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Solution Overview
Problem
Current control logic for determining motor connections in escalators based on load cannot achieve the desired energy-saving effect due to lack of control accuracy.
Innovation Solution
A device and method that use a processor and computer program to determine the operating modes of an AC asynchronous three-phase motor in an escalator system by calculating the slip rate, switching between triangular and star wiring modes based on predefined thresholds to optimize energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If control logic determines motor connection based on load, then energy saving can be achieved, but control accuracy is insufficient
Solution Approach 1:
The patent changes the control parameter from load-based estimation to slip rate-based detection. By measuring the actual slip rate of the motor and comparing it against threshold values, the system achieves precise determination of operating modes (light load, medium load, heavy load) and accordingly switches between star and triangular connections, improving both control accuracy and energy saving effectiveness
Solution Approach 2:
The patent replaces complex mechanical passenger counting systems with an electrical measurement approach. By using the motor's electrical parameters (slip rate calculation from frequency and speed), the system achieves accurate load detection without mechanical sensors or counting devices, thereby improving control accuracy while reducing system complexity
2Measurement precision
If passenger counting systems are used to determine operating modes, then control accuracy improves, but system cost increases
Solution Approach 1:
The patent enables the motor itself to provide the measurement information needed for control decisions. The slip rate, which is inherently present during motor operation, is used as the direct indicator of load conditions. This eliminates the need for external passenger counting systems or additional sensors, achieving accurate load detection using only the motor's own operational parameters
Solution Approach 2:
The patent uses slip rate as an intermediary parameter that connects motor operation to load conditions. Instead of directly counting passengers or measuring load force, the system measures the slip rate (difference between synchronous speed and actual speed) which naturally reflects the load state, providing an indirect but accurate measurement method that is both simple and effective
Data Source
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AI summary
The present application relates to elevator technology, in particular to a device and method for determining operating modes of an AC asynchronous three-phase motor (620) in an escalator system (600) and computer-readable storage medium on which a computer program (540) for implementing the method is stored. In the device (500) for determining operating modes of an AC asynchronous three-phase motor in an escalator system in accordance with an aspect of the present application, the operating modes comprise a first operating mode and a second operating mode, the AC asynchronous three-phase motor adopts a triangular wiring mode and a star wiring mode in the first operating mode and the second operating mode, respectively, the device comprises: a memory (520); a processor (530) coupled with the memory; and a computer program stored on the memory and running on the processor, the running of the computer program causes: A. obtaining a slip rate of the AC asynchronous three-phase motor; and B. determining whether the AC asynchronous three-phase motor needs to be switched between the first operating mode and the second operating mode based on the slip rate.