Elevator Control Switching Between Magnetic-Pole Estimation and Encoder Detection

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Solution Overview

Problem

Conventional elevator devices using magnetic-pole position estimating control struggle to achieve high landing accuracy in stopped or super-low speed states due to limited magnetic pole numbers, which affects accuracy and reliability.

Innovation Solution

The elevator device incorporates a control section that switches between magnetic-pole position estimating control and detector-based running control based on the car's speed or position, utilizing an induction-type rope tester to enhance accuracy and reliability during super-low speed operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If magnetic-pole position estimating control is used to improve low-speed performance, then low-speed control is improved, but landing accuracy in stopped or super-low speed states deteriorates due to limited magnetic pole numbers

Engineering Contradiction:
Improvelow-speed controlVSAvoidlanding accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent introduces an encoder as an intermediary measurement device to supplement the magnetic-pole position estimation. The encoder provides precise position feedback at super-low speeds and stopped states where magnetic-pole estimation becomes unreliable, thereby maintaining landing accuracy across all operating conditions without compromising low-speed control performance

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The control system is designed to perform multiple functions: magnetic-pole position estimation for normal low-speed operation and encoder-based position detection for super-low speed and stopped states. This multi-functional approach ensures both low-speed control capability and high landing accuracy are achieved across the entire speed range

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If magnetic-pole position estimating control is used, then control simplicity is improved, but reliability deteriorates in stopped or super-low speed operation states

Engineering Contradiction:
Improvecontrol simplicityVSAvoidoperational reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements dynamic switching between control methods based on operating conditions. The system automatically transitions from magnetic-pole position estimation to encoder-based control when speed thresholds are exceeded, ensuring reliable operation across all speed ranges while maintaining simplicity in normal operating conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The encoder is pre-installed and ready to provide backup position information before magnetic-pole estimation becomes unreliable. This preparatory measure ensures that when the elevator enters super-low speed or stopped states, accurate position data is immediately available to maintain control reliability without system reconfiguration

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables high landing accuracy even in stopped and super-low speed states by combining magnetic-pole position estimating control with detector-based running control, improving accuracy and reliability in elevator operations.

Implementation Method 1

estimating a magnetic-pole position by using an induced voltage generated by rotation of a motor of a hoisting machine

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2452908B1Elevator device
Publication Date: 2016.08.31 MITSUBISHI ELECTRIC CORP
  • EP2452908B1 patent drawingFigure 1
  • EP2452908B1 patent drawingFigure 2
  • EP2452908B1 patent drawingFigure 3

AI summary

Provided is an elevator device using magnetic-pole position estimating control, which is capable of realizing high landing accuracy even in a stopped state and in a super-low speed operation state. The elevator device using a magnetic-pole position estimating method, for estimating a magnetic-pole position by using an induced voltage generated by rotation of a motor of a hoisting machine (11) to perform running control on a car driven by the rotation of the hoisting machine, includes: a detector (32) provided outside the hoisting machine, for detecting a position or a speed of the car; and a control section (20) for determining whether or not the car is in a switched running state according to a running speed of the car or a current position of the moving car, for performing the running control on the car by using the magnetic-pole position estimating control method when it is determined that the car is not in the switched running state, and for performing the running control on the car based on results of detection by the detector when it is determined that the car is in the switched running state.