Elevator Brake Control Circuit for Smooth Stopping
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Solution Overview
Problem
Existing elevator brake control systems only offer two discrete braking options during a black-out or emergency stop, leading to either rapid or slow braking, which may not result in a smooth retardation of the elevator car, especially when using belts, and fail to provide controlled braking in situations requiring smoother deceleration.
Innovation Solution
A novel brake control system utilizing a rectifier bridge, intermediate circuit, and dual brake control circuits with forward and reverse current paths, allowing for controlled braking by modulating the current through switches and diodes, enabling smoother retardation of the elevator car by managing the energy discharge and re-use between brake inductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If rapid braking is applied by deenergizing both brake coils simultaneously, then the stopping time is reduced, but the retardation becomes too high causing discomfort and potential damage
Solution Approach 1:
The brake control system is segmented into two independent control circuits (first brake control circuit and second brake control circuit) that can operate independently. This allows one brake to be applied first while the other is applied subsequently, enabling staged braking rather than simultaneous full braking, thus reducing peak retardation while maintaining reasonable stopping time.
Solution Approach 2:
The braking process is divided into periodic stages: first brake is energized/deenergized in a first time interval, then the second brake is energized/deenergized in a second time interval. This periodic, sequential action allows control over the braking profile, preventing excessive retardation while achieving timely stopping.
2Object-affected harmful factors
If slow braking is applied by using a diode for reverse voltage, then the retardation is reduced, but the stopping time increases significantly
Solution Approach 1:
By segmenting the braking action into two sequential phases with two separate brakes, the system achieves moderate retardation in each phase rather than prolonged slow braking, optimizing the balance between comfort and stopping time.
Solution Approach 2:
The first and second brakes operate in continuous sequence without idle gaps, maintaining useful braking action throughout the stopping process. This continuous controlled deceleration achieves smooth stopping without excessive total stopping time.
3Device complexity
If only two discrete braking options are available, then the control system is simple, but the ability to achieve smooth controlled stop is limited
Solution Approach 1:
The control system is divided into two independent brake control circuits with separate timing control, allowing flexible combination of braking actions. This segmentation provides multiple braking strategies beyond just two discrete options, enabling smooth controlled stopping while maintaining reasonable system complexity.
Solution Approach 2:
The brake control system dynamically adjusts the timing and sequence of brake activation based on operational requirements. The first and second time intervals can be varied to achieve different braking profiles, providing dynamic control capability that adapts to different stopping scenarios.
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 smooth and controlled braking of the elevator car during black-out or emergency stop situations, adapting to different braking requirements based on the drive situation and speed, ensuring even wear of brake components and improved safety.
Implementation Method 1
The first brake inductor L1 in the first brake BR1 and the second brake inductor L2 in the second brake BR2 can be energized and deenergized in a controlled way
Implementation Method 2
The electromagnet comprises one or several coils and an armature. The electromagnet can be energized with an electric current, whereby a magnetic field is produced in the electromagnet. The magnetic field will attract a counterpart of the armature.
Data Source
Figure 1
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Figure 3
AI summary
The brake control system (300) comprises a rectifier bridge (RB1), an intermediate circuit (IC1) having a capacitor (C1), a first brake circuit (BC1) having a first brake inductor (L1) and a second brake circuit (BC2) having a second brake inductor (L2). At least one of the first brake circuit (BC1) and the second brake circuit (BC2) is provided with two current paths so that the brake inductor (L1, L2) can be connected to the capacitor (C1) in the intermediate circuit (IC1) in a forward direction in order to charge energy into the brake inductor (L1, L2) and in a reverse direction in order to discharge energy from the brake inductor (L1, L2). The energy discharged from the brake inductor (L1, L2) is used in the other brake control circuit (BC1, BC2) to control the braking of the other brake (BR1, BR2) to cause a controlled smooth stop of the elevator car (10).