Multi-Mode Load Control Circuit for Lighting Occupancy Sensing
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Solution Overview
Problem
Existing lighting control systems require manual intervention to keep lights on during afterhours mode, which is disruptive and inefficient, and occupancy or vacancy sensors must be disabled, limiting energy savings.
Innovation Solution
A multi-modal load control system that automatically switches between occupancy and vacancy sensor modes based on time of day, allowing lights to turn on only when occupied during normal hours and turning off when unoccupied, including a sensor and load control circuit that can operate in series with the power source to manage power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If occupancy sensors are disabled during afterhours mode to prevent unnecessary light activation, then energy savings are improved, but manual intervention is required to turn lights on when needed
Solution Approach 1:
The sensor system dynamically changes its operational mode based on the time of day. During afterhours, the system automatically transitions from occupancy sensing mode to vacancy sensing mode, allowing lights to remain on until explicitly turned off by vacancy detection, eliminating the need for manual reactivation while preserving energy
Solution Approach 2:
The lighting system serves itself by automatically adjusting sensor behavior based on temporal context. The system self-regulates between occupancy and vacancy sensing modes without user intervention, adapting to different operational periods (work hours vs. afterhours) to balance energy efficiency and user convenience
2Ease of operation
If occupancy sensors remain enabled during afterhours mode to allow automatic light activation, then ease of operation is improved, but unnecessary light activation occurs when security personnel or other individuals occupy the space
Solution Approach 1:
The system dynamically switches sensor operational modes based on time-of-day parameters. During afterhours periods, the system transitions to vacancy sensing mode where lights remain off until explicitly turned on, preventing false activation by security personnel while maintaining automatic control
Solution Approach 2:
The system changes the operational parameter of the sensor from occupancy detection to vacancy detection based on the time parameter. This parameter change allows the system to differentiate between work hours (where occupancy activation is desired) and afterhours (where vacancy-based control is preferred)
3Loss of energy
If manual buttons are required to keep lights on during afterhours mode, then energy savings are improved, but user convenience deteriorates due to repetitive actuation
Solution Approach 1:
The lighting system provides self-service during afterhours by automatically maintaining the on state once activated. The system monitors vacancy conditions and keeps lights on until the space is unoccupied, eliminating the need for users to repeatedly press buttons to extend lighting duration
Solution Approach 2:
The system prepares for afterhours operation by pre-configuring vacancy sensing mode activation. When afterhours begins, the system is already prepared to automatically manage lighting based on vacancy detection, eliminating the need for preliminary manual setup or repetitive user actions
Data Source
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AI summary
A multi-modal load control system includes a sensor that operates as an occupancy sensor in a first mode of operation and operates as a vacancy sensor in a second mode of operation. The load control system comprises a load control circuit adapted to be coupled in series electrical connection between an AC power source and an electrical load for controlling the amount of power delivered to the load in response to sensor, which is operable to detect occupancy or vacancy conditions in a space in which the sensor is located. In the first mode of operation, the load control circuit turns the load on when the sensor detects the occupancy condition and turns the load off when the sensor detects the vacancy condition. In the second mode of operation, the load control circuit turns the load off when the sensor detects the vacancy condition and does not turn the load on when the sensor detects the occupancy condition.