Elevator Deceleration via Linear Synchronous Reluctance Motor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-speed self-propelled elevator systems face issues with abrupt deceleration during faults, such as power loss, leading to potential freefall scenarios due to deceleration rates exceeding gravity, and existing systems lack effective mechanisms for smooth deceleration and braking.
Innovation Solution
The elevator system incorporates a dual propulsion system with energy storage units and a controller that powers both propulsion systems during faults, along with a delayed braking mechanism to ensure smooth deceleration and a unidirectional brake that applies force only during downward movement, utilizing a linear synchronous reluctance motor and energy storage to manage deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single propulsion system is used for high-speed elevator travel, then productivity and speed are improved, but reliability deteriorates due to risk of abrupt deceleration during faults
Solution Approach 1:
The patent applies local quality by assigning different functions to different propulsion systems: the first propulsion system handles normal high-speed operation, while the second propulsion system is specifically dedicated to fault condition deceleration control. This functional differentiation ensures that each system is optimized for its specific purpose, maintaining high productivity during normal operation while ensuring reliability during faults.
Solution Approach 2:
The patent implements preliminary action by having the second propulsion system pre-positioned and ready to activate immediately upon fault detection. The system includes pre-configured control logic that automatically engages the second propulsion system when a fault is detected in the first system, eliminating response delays and ensuring immediate deceleration control without compromising reliability.
2Loss of energy
If friction forces or motor windings create drag forces during upward travel, then energy efficiency is improved, but harmful factors worsen due to excessive deceleration exceeding gravity
Solution Approach 1:
The patent applies preliminary anti-action by having the second propulsion system activate in opposition to excessive deceleration forces before they can harm passengers. When drag forces from friction or shorted windings cause deceleration to exceed gravity, the second propulsion system generates counteracting thrust to limit deceleration to safe levels, preventing freefall conditions and passenger injury.
Solution Approach 2:
The second propulsion system serves as an intermediary between the harmful drag forces and the elevator car/passengers. Rather than allowing drag forces to directly cause excessive deceleration, the second propulsion system mediates by providing compensating force, transforming the harmful effect into a controlled deceleration profile that protects passengers while still allowing energy-efficient operation during normal conditions.
3Reliability
If brake is applied immediately upon fault detection, then reliability is improved by quickly stopping the elevator, but harmful factors worsen due to abrupt deceleration causing passenger discomfort and potential injury
Solution Approach 1:
The patent implements beforehand cushioning by using the second propulsion system to provide gradual deceleration before the mechanical brake engages. This cushioning phase limits deceleration to less than 1g, preventing abrupt stops and passenger injury. The brake is delayed until the elevator speed reduces to a safe threshold, ensuring that when the brake finally engages, the car is moving slowly enough to avoid harmful impacts.
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
The system achieves smooth deceleration of the elevator car during upward travel faults, limiting deceleration rates to less than 1 G and delaying brake engagement until safe speeds are reached, thereby preventing passenger discomfort and ensuring safe operation.
Implementation Method 1
a linear synchronous reluctance motor including: a primary circuit having a plurality of primary poles and windings about the primary poles; a secondary circuit having a plurality of secondary poles
Implementation Method 2
a biasing member configured to assume an extended position and a retracted position, the biasing member positioning the wedge in the wedge guide when the biasing member is in the extended position
Implementation Method 3
a wedge configured to apply a braking force to the guide rail only upon downward movement of the elevator car
Data Source
AI summary
An elevator system includes an elevator car; a guide rail; and a linear synchronous reluctance motor including: a primary circuit having a plurality of primary poles and windings about the primary poles; a secondary circuit having a plurality of secondary poles; the primary circuit coupled to one of the elevator car and the guide rail, the secondary circuit coupled to the other of the elevator car and the guide rail.