Elevator Brake Control via Optical Switching
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Solution Overview
Problem
In machine room-less elevators, the long electrical connections required for the brake release switch to the elevator brake and emergency power supply are costly and inefficient, especially when a large electrical current is needed to release the brake against mechanical biasing forces.
Innovation Solution
The elevator brake control system uses two power semiconductor switching devices connected in series, with a brake control circuit that supplies control signals to these devices to manage the brake's engaged and released states, allowing for redundant brake release and performance functions without the need for long electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a brake release switch is located at an accessible position in the hoistway or outside the hoistway for manual rescue operations, then the ease of operation is improved, but the length of electrical connections required to the brake and emergency power supply increases significantly
Solution Approach 1:
The patent replaces the mechanical/electrical brake release switch system with an optical communication system. The brake release command is transmitted via optical signals (light) through the hoistway communication network, eliminating the need for long electrical connections between the accessible brake release switch and the brake mechanism or power supply.
Solution Approach 2:
The patent introduces an optical communication network as an intermediary medium. The brake release switch communicates with the control system through optical signals that are relayed via communication nodes in the hoistway, allowing the switch to be located at an accessible position without requiring direct long electrical connections to the brake components.
2Ease of operation
If long electrical connections are used for the brake release switch to the elevator brake and emergency power supply, then the ease of operation is improved, but the device complexity and cost increase
Solution Approach 1:
The patent substitutes the complex electrical connection system with an optical communication system. Instead of running heavy-gauge electrical cables through the hoistway for power and control signals, the system uses optical communication nodes that transmit commands and power through light signals, significantly reducing system complexity.
Solution Approach 2:
The optical communication network serves multiple functions simultaneously: it transmits brake release commands, provides emergency power supply, and enables communication between various hoistway components. This multi-functionality eliminates the need for separate dedicated electrical connections for each function, reducing overall system complexity.
3Ease of operation
If long electrical connections are used for the brake release switch to the elevator brake and emergency power supply, then the ease of operation is improved, but the loss of energy increases due to large electrical current requirements
Solution Approach 1:
The patent replaces the electrical current transmission system with an optical communication system. The brake release command is transmitted as optical signals that require minimal energy, eliminating the substantial energy losses that would occur in long electrical connections carrying large currents to release the brake against mechanical biasing forces.
Solution Approach 2:
The optical communication network acts as an energy-efficient intermediary. Instead of directly transmitting high-current electrical signals over long distances (which would incur significant I²R losses), the system uses optical nodes that can amplify and relay signals with minimal energy loss, efficiently delivering the brake release command to the brake mechanism.
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 solution provides a safer and more efficient elevator brake control system by reducing the complexity and cost of electrical connections while maintaining a level of safety comparable to conventional systems, as specified in relevant safety codes.
Implementation Method 1
The brake control circuit is configured to supply a first control signal to a gate terminal of the first power semiconductor switching device and to supply a second control signal to a gate terminal of the second power semiconductor switching device
Data Source
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AI summary
An elevator brake control system (10) is described, in particular for controlling an elevator brake in a machine room-less elevator, the elevator including a drive machine drivingly coupled to an elevator car for moving the elevator car between a plurality of landings in a hoistway, and an elevator brake having at least an engaged condition for holding the elevator car at a fixed position in the hoistway, and a released condition for allowing the elevator car to move along the hoistway; the elevator brake control system (10) comprising a first safety device (T1) and a second safety device (T2), each of the first safety device (T1) and the second safety device (T2) responsive to detection of a failure in any sub-system of the elevator, such as to bring the elevator brake into its engaged condition in response to detection of such failure; wherein each of the first safety device (T1) and the second safety device (T2) comprises a power semiconductor switching device.