Distributed Plug Load Controllers Using Unique Timers
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Solution Overview
Problem
Existing plug load control systems in buildings face issues with network overhead and single-point failures, particularly when central controllers manage both lighting and plug load control, leading to increased costs and installation challenges due to the need for duplicate occupancy sensors and dedicated gateways.
Innovation Solution
A distributed control system with multiple distributed controllers that communicate with each other to coordinate the control of slave devices, using unique timers to prevent redundant control signals and reduce network traffic, allowing only one controller to send a control signal to a slave device, thus minimizing network overhead and eliminating the need for a dedicated central controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single central controller is used to control plug load systems, then the control function is simplified, but the system becomes a single point of failure and network overhead increases
Solution Approach 1:
The patent divides the central controller into multiple distributed controllers (plug load controllers) that are distributed throughout the network. Each controller can independently make control decisions, eliminating the single point of failure. The segmentation transforms a centralized architecture into a distributed one where control functions are spread across multiple nodes, improving system reliability while maintaining manageable complexity through standardized communication protocols.
2Adaptability or versatility
If a dedicated gateway is installed for plug load control, then control functionality is improved, but installation cost and complexity increase
Solution Approach 1:
The patent makes existing lighting controllers multi-functional by enabling them to perform both lighting control and plug load control functions. The distributed controllers can manage multiple types of loads (lighting, receptacles, HVAC) through a unified control mechanism. This eliminates the need for separate dedicated gateways or additional occupancy sensors, reducing installation costs while maintaining full control functionality across different device types.
3Reliability
If multiple distributed controllers are used to eliminate single point of failure, then system reliability is improved, but network overhead increases due to coordination requirements
Solution Approach 1:
The patent implements preliminary action through occupancy prediction and pre-cooling/pre-heating strategies. Controllers predict future occupancy based on historical data and schedules, allowing them to pre-adjust plug loads before actual occupancy changes occur. This reduces real-time network communication requirements because control decisions are made based on predictions rather than continuous sensor feedback, thereby reducing network overhead while maintaining reliable distributed control.
Solution Approach 2:
The patent uses copying by having distributed controllers share occupancy and control state information through the network. When one controller detects occupancy changes, it notifies other controllers in the same zone, allowing them to update their local state without direct sensor readings. This copying mechanism reduces redundant network traffic compared to having each controller independently query sensors, while still maintaining the benefits of distributed control and system redundancy.
4Measurement precision
If occupancy sensors are duplicated for both lighting and plug load control, then control accuracy is improved, but installation cost increases
Solution Approach 1:
The patent makes existing occupancy sensors multi-functional by enabling them to serve both lighting control and plug load control purposes. The distributed controllers access occupancy information from shared sensors rather than requiring duplicate sensor installations. This approach maintains measurement precision for both control functions while eliminating the need for additional physical sensors, thereby reducing installation costs and device quantity.
Data Source
AI summary
A distributed control system including a plurality of controllers, each controller of the plurality of controllers being in communication with the remaining controllers of the plurality of controllers, each controller being configured to control at least one device, each controller being further configured to: initiate a first timer, in response to a received signal, the first timer having a length that is unique with respect to the first timer lengths of the remaining controllers of the plurality of controllers; send a first notification signal, upon the expiration of the first timer, to the remaining controllers notifying the remaining controllers of an intent to send a command signal; send the command signal to the at least one device, wherein the controller is configured to cancel sending the notification signal and the command signal if the notification signal is first received from one of the remaining controllers of the plurality of controllers prior to the expiration of the first timer.