Motorized Screen Drive Control After Power Loss

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Solution Overview

Problem

Motorized drive devices in home automation systems face issues with premature wear due to frequent adjustments after power outages and the need to meet low standby consumption standards, which limits capacitor size and charging voltage, leading to potential discrepancies in screen position after power restoration.

Innovation Solution

A control method that detects whether the screen position has been modified during a power cut and only adjusts it when necessary upon power restoration, avoiding systematic readjustments and utilizing energy transfer to maintain power to the electronic control circuit for a predefined duration to monitor potential movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the screen position is systematically recalibrated after each power interruption, then the position accuracy is improved, but the mechanical components wear out prematurely

Engineering Contradiction:
Improvescreen position accuracyVSAvoidmechanical component lifespan
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system performs position detection during the power interruption itself, rather than waiting until power is restored. By detecting whether the screen moved during the outage and storing this information, the system prepares in advance to avoid unnecessary recalibration, thus protecting mechanical components from premature wear.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from position detection during power interruption to determine whether recalibration is actually needed. If the detected position matches the expected position, the system skips recalibration; if it differs, recalibration is performed only when necessary, optimizing both accuracy and component lifespan.

Inventive Principle:
Principle #23Feedback

2Use of energy by stationary object

If the capacitor charging voltage is limited to meet standby consumption standards, then the standby power consumption is reduced, but the capacitor size must be increased

Engineering Contradiction:
Improvestandby power consumptionVSAvoidcapacitor size
Core Design Contradiction:
Use of energy by stationary objectVSVolume of stationary object

Solution Approach 1:

The capacitor is charged to a higher voltage during power interruptions before the standby consumption limitation takes effect. This preliminary charging action stores sufficient energy in advance to cover the detection period, allowing the system to maintain low standby consumption while still having enough energy储备 for position monitoring.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the capacitor charging voltage based on the situation - during power interruptions, the capacitor can be charged to a higher voltage than the normal standby limit, providing sufficient energy for detection without requiring a permanently larger capacitor.

Inventive Principle:
Principle #35Parameter changes

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 approach reduces premature wear of mechanical components and ensures accurate screen positioning upon power restoration, while maintaining compliance with low standby consumption standards, thus extending the lifespan of the automation installation.

Implementation Method 1

the actuator includes a capacitor supplying the electronic circuit for periods of mains power outage

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3924788B1Control method, motorised drive device, home automation installation comprising such a motorised drive device
Publication Date: 2025.01.15 SOMFY ACTIVITES SA
  • EP3924788B1 patent drawingFigure 1
  • EP3924788B1 patent drawingFigure 2
  • EP3924788B1 patent drawingFigure 3

AI summary

The invention relates to a method for controlling a motorised drive device including an actuator coupled with a mechanical load, comprising the steps of: a) detecting (100) a loss of electrical power; b) subsequent to detecting a loss of power, transferring (102) at least a portion of the energy stored in a first capacitor connected to the input of a voltage regulator of the drive device, to a second capacitor connected to the output of the voltage regulator; c) determining (104, 106), during a first period of time following the loss of power, whether the load has moved; d) when power is restored, controlling (112) the movement of the load into a predefined reference position if a movement of the mechanical load has been determined, or otherwise maintaining the load in its current position.