PoE Switch Standby Power Reduction via Keep-Alive Signaling

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Solution Overview

Problem

Existing Power over Ethernet (PoE) lighting systems consume standby power when luminaires are not in use, as they are typically configured to remain always on, lacking a method to efficiently switch off power without specialized controllers or commissioning.

Innovation Solution

A network switch and luminaire configuration that passively listens for communication activity to determine power supply, using a predetermined shut-off period to switch off power when activity ceases, with a firmware-updatable PoE switch and luminaire that send 'keep alive' signals to maintain power, reducing standby consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PoE switches supply power to luminaires continuously, then the luminaires remain always on and ready for operation, but standby power is consumed when luminaires are not in use

Engineering Contradiction:
Improvereadiness of luminaireVSAvoidstandby power consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The PoE switch monitors communication activity from luminaires and uses this feedback to control power supply. When no communication signals are detected within a predetermined period, the switch automatically cuts off power to that luminaire, thereby eliminating standby power consumption while maintaining readiness through automatic re-powering upon detection of communication activity.

Inventive Principle:
Principle #23Feedback

2Loss of energy

If PoE switches are configured to switch off power to inactive luminaires, then standby power consumption is minimized, but specialized lighting network controllers or individual commissioning of PoE switches is required

Engineering Contradiction:
Improvestandby power consumptionVSAvoidcontroller complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The PoE switch performs self-service by automatically monitoring communication activity on its ports and autonomously deciding when to supply or cut off power to connected luminaires. This eliminates the need for specialized external controllers or complex commissioning procedures, as the switch uses its built-in capability to detect communication signals and control power accordingly.

Inventive Principle:
Principle #25Self-service

3Loss of energy

If PoE switches monitor communication activity to control power supply, then power is efficiently managed, but the switch requires configuration or firmware updates

Engineering Contradiction:
Improvepower efficiencyVSAvoidswitch configuration
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The PoE switch implements a simplified version of power management by monitoring only communication activity presence rather than implementing full-featured lighting control protocols. This partial action approach achieves significant power efficiency benefits while avoiding the need for complex configuration or extensive firmware modifications, as it uses the switch's inherent communication monitoring capability.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2748975B1Electrical lighting system power control
Publication Date: 2019.04.03 SIGNIFY HOLDING BV
  • EP2748975B1 patent drawingFigure 1
  • EP2748975B1 patent drawingFigure 2~4
  • EP2748975B1 patent drawingFigure 3~5

AI summary

A network switch (5) for example a PoE switch, is operable to control supply of electrical power to individual luminaires (1,2) in a lighting network. The luminaires receive both electrical power for operation and signals to switch on and off through a common cable connection (9) such as an Ethernet connection. When switched on, each luminaire sends a signal repeatedly towards the Po E switch until switched off and the switch (5) supplies power to the luminaire whilst successive signals are received within a period less than a predetermined shut off period (Delta). In this way, power to the luminaire can be disconnected to avoid comsumption of standby power when not in use.