Lighting Load State Correction After Local and System Power Loss
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Solution Overview
Problem
Existing load control systems for lighting devices face challenges in distinguishing between intentional and unintentional power removal events, leading to undesirable default intensity levels when power is restored, especially during blackouts or brownouts.
Innovation Solution
A load control system that includes control devices with memory to store and recall power states, using sensors and communication protocols to differentiate between local and system power removal events, allowing for state correction and maintaining pre-power removal settings upon power restoration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the light bulbs are set to default intensity level upon power restoration, then the system operates with simple power management, but the user experience deteriorates during unintentional power removal events
Solution Approach 1:
The system performs preliminary actions by storing the power state of lighting devices before power removal occurs. The hub device monitors and records the operational state (intensity level, on/off status) of each lighting device, so that when power is restored, the pre-stored state can be immediately recalled without requiring complex real-time decision-making.
Solution Approach 2:
The hub device serves as an intermediary between the power source and the lighting devices. It mediates the power restoration process by receiving power restoration signals, determining whether the event was intentional or unintentional, and then instructing the lighting devices to return to their pre-stored states. This intermediary layer enables intelligent state management without adding complexity to the lighting devices themselves.
2Reliability
If the system distinguishes between intentional and unintentional power removal events, then the state retention accuracy improves, but the device complexity increases
Solution Approach 1:
The system segments the power event detection function across multiple components: the hub device detects system-wide power removal events, while individual lighting devices detect local power removal events. This segmentation allows each component to have simpler detection logic while collectively achieving accurate distinction between intentional and unintentional power removal events.
Solution Approach 2:
The system uses feedback mechanisms where the hub device communicates with lighting devices to determine the nature of power removal events. When power is restored, the hub device receives signals from lighting devices about their power state, and based on this feedback, determines whether the power removal was intentional (user-controlled) or unintentional (power outage), enabling accurate state retention decisions.
3Reliability
If the lighting devices return to pre-power removal states, then the user experience improves during blackouts, but the system requires more complex memory and control mechanisms
Solution Approach 1:
The system merges the memory and control functions into the hub device rather than requiring each lighting device to have independent memory and control capabilities. The hub device stores the power states of multiple lighting devices and manages the restoration process centrally, reducing the complexity burden on individual lighting devices while maintaining accurate state restoration.
Solution Approach 2:
The system creates a copy of the power state information (intensity level, on/off status) and stores it in the hub device's memory. This copied state data can be easily retrieved and applied when power is restored, eliminating the need for complex real-time calculations or state reconstruction, thereby simplifying the control mechanism while ensuring accurate state restoration.
Data Source
AI summary
A device may detect a power removal event, determine whether the power removal event is a local power removal event or a system power removal event, and perform state correction. For example, the device may receive an indication of a state change event turning on the lighting device. The indication may be received from a sensor. For example, the sensor may include a photosensing circuit (e.g., capable of detecting light emission from the lighting device) or the sensor may include a live voltage sensor (e.g., capable of detecting a change in current driven to the lighting device). The device may then determine whether the power removal event is a system power removal event or a local power removal event. If the device determines that the power removal event is a system power removal event, the device may perform state correction (e.g., setting the lighting device to its state prior to the power removal event).