Elevator Brake Control Circuit for Emergency Stop

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Solution Overview

Problem

Conventional elevator brake systems experience uncomfortable deceleration and noise due to high braking force and kinetic energy, requiring precise manufacturing tolerances and fragile structures to minimize the brake pad's air gap, which is difficult to implement and adjust effectively.

Innovation Solution

A brake control circuit that uses a first switch to control the electricity supply to the brake winding with short pulses, allowing for adjustable braking force and noise reduction by managing the current profile, and includes a capacitor for energy storage and an overvoltage protector, reducing the need for a conventional attenuation circuit and enabling safer, more comfortable emergency stops.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the brake current is increased to provide stronger braking force for emergency stops, then the braking capability is improved, but the deceleration becomes too harsh and uncomfortable for passengers

Engineering Contradiction:
Improvebraking forceVSAvoidpassenger discomfort
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The brake control circuit uses pulsed current delivery instead of continuous current. The controller applies periodic pulses of current to the brake winding, allowing the brake to engage and disengage in a controlled manner. This periodic action enables the brake to provide sufficient stopping force while avoiding continuous high-force application that would cause passenger discomfort during emergency stops.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The brake control circuit dynamically adjusts the brake current based on real-time conditions. The controller monitors elevator speed, position, and other parameters to modulate the brake current amplitude and pulse frequency. This dynamic control allows the system to optimize braking force at different stages of the stopping process, providing strong initial deceleration when needed while reducing force as the elevator approaches the target floor to ensure passenger comfort.

Inventive Principle:
Principle #15Dynamics

2Object-generated harmful factors

If the air gap between the brake pad and braking surface is minimized to reduce noise and impact, then the noise level is reduced, but the structure becomes fragile and manufacturing tolerances become extremely precise

Engineering Contradiction:
ImprovenoiseVSAvoidair gap tolerance
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The invention replaces the mechanical adjustment mechanism for air gap control with an electrical control system. Instead of relying on precise mechanical positioning and adjustment of the brake pad distance from the braking surface, the system uses electronic control of the brake winding current to regulate brake engagement. This substitution of mechanical adjustment with electrical control eliminates the need for extremely precise mechanical tolerances while still achieving low noise and smooth operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution provides a simpler, safer, and more pleasant elevator experience by adjusting braking force and noise levels, improving the overall operation of the elevator system during emergency stops without the need for precise manufacturing tolerances or fragile structures.

Implementation Method 1

a first switch (4) controlling the electricity supply of a winding (3) of the brake (2), wherein the first switch (4) is switched in a controlled manner with short pulses

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A capacitor (10) is connected between the rails (5, 5') that transfer output current and return current to the intermediate circuit of the brake control circuit

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3549894B1Elevator system
Publication Date: 2021.07.07 KONE OYJ
  • EP3549894B1 patent drawingFigure 1
  • EP3549894B1 patent drawingFigure 2
  • EP3549894B1 patent drawingFigure 3a~3d

AI summary

The present invention is about an elevator system with a movement control system (14) setting a movement reference (16) for an elevator car. Said movement control system (14) regulates the movement (18) by means of a brake control circuit (1) during an emergency stop by adjusting the current of a winding (3) of a brake and thus the braking force of the brake (2) of the elevator so that the movement (18) of the elevator car approaches the reference (16) set for the movement.