Elevator Controller Emergency Deceleration Strategy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Elevator systems are dependent on external power sources, making it challenging to bring the elevator to a controlled stop when power is unavailable, which can lead to safety issues and equipment damage.
Innovation Solution
A controller-based method and apparatus that detect the operating mode of the elevator and adjust its velocity to a controlled stop using battery power, back-emf braking, and gravity, allowing for safe deceleration and braking when external power is unavailable, utilizing a battery as a backup power source and an inverter to convert DC to AC power for driving the elevator car.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the elevator system relies on external power source for operation, then the elevator can operate normally with sufficient power, but the elevator cannot be brought to a controlled stop when external power is unavailable
Solution Approach 1:
The system performs preliminary actions by detecting power availability status before attempting to stop the elevator, and by pre-establishing different deceleration strategies based on the detected mode (motoring, regenerative, or near-balance). This allows the controller to prepare the appropriate stopping procedure in advance, ensuring a controlled stop can be achieved regardless of power source availability.
Solution Approach 2:
The system changes operational parameters by adjusting deceleration rates and velocity maintenance strategies based on the detected operating mode. When external power is unavailable, the controller modifies the deceleration profile to utilize gravity and momentum appropriately for each mode (e.g., allowing velocity to decrease to creep velocity in regenerative mode, or maintaining velocity in motoring mode), enabling controlled stopping under varying power conditions.
2Manufacturing precision
If the elevator uses traditional motoring mode deceleration with external power, then the deceleration can be controlled precisely, but the deceleration strategy becomes inadequate when external power is unavailable
Solution Approach 1:
The system implements dynamic deceleration control by continuously monitoring the operating mode and adjusting the deceleration strategy in real-time. The controller dynamically selects between different deceleration approaches: using motor braking in motoring mode, utilizing regenerative braking with creep velocity in regenerative mode, or applying gravity-assisted deceleration in near-balance mode. This dynamic adaptation maintains deceleration precision across all power availability scenarios.
Solution Approach 2:
The system employs feedback mechanisms by detecting the current operating mode (motoring, regenerative, or near-balance) and using this information to adjust the deceleration profile. The controller continuously monitors velocity, power availability, and mode status, then modifies the deceleration rate and stopping strategy accordingly, ensuring precise controlled stop achievement regardless of external power status.
3Use of energy by moving object
If the elevator allows velocity to decrease naturally without control, then power consumption is reduced, but the elevator cannot reach a safe controlled stop
Solution Approach 1:
The system utilizes self-service principles by leveraging the elevator's own momentum, gravity, and operating mode characteristics to achieve deceleration without requiring additional external power. In regenerative mode, the system allows velocity to naturally decrease to creep velocity while recovering energy. In near-balance mode, gravity assists the deceleration process. This self-service approach enables safe controlled stopping while minimizing power consumption during the deceleration phase.
Solution Approach 2:
The system converts potentially harmful uncontrolled velocity decrease into beneficial controlled deceleration by utilizing the operating mode detection to transform gravity and momentum from unpredictable factors into controlled deceleration forces. In near-balance mode, gravity which could cause uncontrolled movement is instead harnessed to assist deceleration. In regenerative mode, the natural velocity decrease is converted into energy recovery while maintaining controlled stopping capability.
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
Enables a controlled and safe stop of the elevator car at the target floor even without external power, protecting the equipment and ensuring passenger safety by using battery power and regenerative modes to manage deceleration effectively.
Implementation Method 1
utilizing a battery as a backup power source and an inverter to convert DC to AC power for driving the elevator car
Implementation Method 2
A controller-based method and apparatus that detect the operating mode of the elevator and adjust its velocity to a controlled stop using battery power, back-emf braking, and gravity
Implementation Method 3
A controller-based method and apparatus that detect the operating mode of the elevator and adjust its velocity to a controlled stop using battery power, back-emf braking, and gravity
Data Source
Figure 1
Figure 2
Figure 3
AI summary
According to one embodiment, a method of operating an elevator system is provided. The method includes detecting, using a controller, when an external power source is unavailable. The method also includes controlling, using the controller, a plurality of components of the elevator system. The controlling comprises operating at least one of an elevator car, a drive unit, an inverter and a brake. The method further includes detecting, using the controller, an original direction of travel of the elevator car. The method yet further includes detecting, using the controller, a mode of the elevator car, wherein the mode includes at least one of a motoring mode, a near balance mode, and a regenerative mode. The method includes determining, using the controller, a target floor. The method also includes adjusting, using the controller, a velocity of the elevator car to reach the target floor in response to the mode detected.