Lighting System Defective Device Detection via Power Consumption Analysis
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Solution Overview
Problem
Existing lighting systems are expensive and inefficient in detecting defective lighting devices, especially in systems where individual devices cannot be identified or selected for testing.
Innovation Solution
A method and system that sends a change operational state command to a group of lighting devices with randomized or individual delays, detecting changes in total drive power and generating an error signal if the number of changes is below a nominal number multiplied by a constant, allowing for the detection of defective devices without individual identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individualized testing of lighting devices is implemented, then defective devices can be detected, but the system cost increases significantly
Solution Approach 1:
The patent merges multiple lighting devices into a single group controlled by one control unit. Instead of individually testing each device, the system sends a single change operational state command to the entire group and detects the total power consumption change. This combining approach maintains defective device detection capability while significantly reducing system complexity and cost compared to individualized testing systems.
Solution Approach 2:
The system uses the lighting devices' own power consumption characteristics as the detection mechanism. When devices change operational state, their power consumption changes naturally, and the control unit detects these self-generated power changes to identify defective devices. This eliminates the need for additional testing hardware or complex identification procedures, reducing system cost while maintaining detection reliability.
2Device complexity
If simple communication structure is used without individual device identification, then system cost is reduced, but defective device detection becomes difficult
Solution Approach 1:
The system implements periodic testing by sending change operational state commands at scheduled intervals and measuring power consumption at corresponding measurement points. This periodic approach allows the simple communication structure to effectively detect defective devices by comparing power changes over time, maintaining detection reliability without requiring complex continuous monitoring or individual device identification protocols.
Solution Approach 2:
The patent replaces complex mechanical or electronic identification systems with a power consumption-based detection method. Instead of using individual device addresses, selection signals, or physical identification mechanisms, the system substitutes a simpler power measurement approach that infers device status from total group power consumption changes, achieving both simplicity and reliability.
3Reliability
If random delays are applied to lighting devices, then defective devices can be detected in non-identifiable systems, but timing precision requirements increase
Solution Approach 1:
The system applies random delays to the execution of change operational state commands across different lighting devices before they actually change state. This preliminary randomization prevents synchronized switching that would mask individual device failures. The control unit accounts for these delays by scheduling power consumption measurements at appropriate times, ensuring defective devices can be detected through their anomalous power consumption patterns despite the timing variations.
Data Source
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AI summary
A lighting system and a corresponding method are provided. The method comprises: sending a change operational state command to a lighting device group (3) comprising several lighting devices (9); at each lighting device, applying a randomized delay within a predetermined delay interval or an individual predetermined delay within the delay interval; changing the operational state in accordance with the change operational state command at each lighting device at the end of each respective delay; detecting changes in the total drive power fed to the group of lighting devices within the delay interval and counting the total number of changes; comparing the total number of changes with a nominal number corresponding with the number of lighting devices within the group of lighting devices; generating a lighting device error signal if the number of changes is smaller than a predetermined fraction of the nominal number, including the nominal number.