Movable Elevator Rail Drive Segmentation for Fault-Tolerant Operation
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Solution Overview
Problem
Elevator systems with movable rail segments face high reliability demands due to the significant capacity reduction and potential system failure when one shaft fails, especially in systems where the failure of a movable rail segment interrupts the vertical travel path.
Innovation Solution
A drive arrangement with redundant inverter units and electric motors, allowing for decentralized decision-making and independent operation of drive segments, which includes a master communication unit to manage and synchronize state values among slave units, ensuring continued operation even if individual components fail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional elevator system with multiple shafts is used to increase passenger transport capacity, then the total capacity increases, but the failure of one shaft causes a proportional reduction in capacity (e.g., 20% reduction with five shafts)
Solution Approach 1:
The elevator system is divided into multiple independent drive segments, each capable of autonomous operation. Each drive segment controls a specific movable rail segment and can operate independently, allowing the system to maintain functionality even when individual segments fail. This segmentation transforms the system from a monolithic structure where one failure affects the whole, to a modular system where failures are isolated to specific segments only.
Solution Approach 2:
The system changes its operational parameters dynamically based on the functional status of drive segments. When a segment fails, the system reconfigures its operational mode to maintain service with reduced capacity rather than complete shutdown. This parameter change approach allows the system to adapt its performance level to match the available functional components, ensuring continuous operation at a reduced but non-zero capacity.
2Productivity
If movable rail segments are used to enable circumferential travel and increase capacity, then passenger transport capacity increases significantly, but the failure of a movable rail segment interrupts the vertical travel path and may cause complete system failure
Solution Approach 1:
The drive system is segmented into multiple independent drive segments, each responsible for a specific movable rail segment. This segmentation ensures that a failure in one drive segment does not propagate to other segments, allowing the elevator system to continue operating with reduced capacity rather than complete shutdown.
Solution Approach 2:
The system incorporates redundant drive segments that serve as backup capacity before failures occur. This beforehand cushioning ensures that when a drive segment fails, the system has pre-positioned alternative segments that can immediately take over, preventing complete system failure and maintaining continuous operation.
3Reliability
If redundant inverter units and electric motors are implemented to improve reliability, then system reliability increases, but device complexity increases
Solution Approach 1:
The control system is segmented into multiple independent inverter units, each controlling a specific drive segment. This segmentation allows for decentralized decision-making where each inverter unit can operate autonomously, reducing the complexity of centralized control while maintaining system reliability through redundancy.
Solution Approach 2:
Each drive segment is equipped with its own inverter unit and control capabilities, enabling self-service operation. When a segment fails, the remaining segments can independently continue operation without requiring complex centralized reconfiguration, thereby reducing overall system complexity while maintaining reliability.
4Reliability
If decentralized decision-making is implemented among drive segments, then system reliability improves through independent operation, but communication and synchronization requirements increase complexity
Solution Approach 1:
Each drive segment is designed with self-service capabilities, including autonomous decision-making and self-synchronization functions. This reduces the need for complex centralized communication protocols, as each segment can independently manage its operation and coordinate with others through simpler peer-to-peer communication.
Solution Approach 2:
The communication functions are merged into the existing inverter units, which already possess processing and control capabilities. By combining communication, control, and drive functions within each inverter unit, the system reduces overall communication complexity while maintaining decentralized operation and synchronization capabilities.
Data Source
AI summary
A drive arrangement includes a movable, rotatable rail segment of an elevator system. An electric motor moves the movable rail segment. The drive arrangement is configured to rotate the rail segment about an angle of rotation of less than 360°. An inverter unit provides electrical power to the electric motor and is configured to receive a control command relating to the position of the movable rail segment and provide the electrical drive power based on the control command. The drive arrangement forms two or exactly three drive segments. Each drive segment includes an inverter unit and a coil arrangement, which is supplied with electrical power by the assigned inverter unit. Each inverter unit includes a communication unit, which receives the control command. The communication units are configured to specify amongst themselves a master communication unit and to specify the remaining communication unit as slave communication units.