HVAC system with multivariable optimization using a plurality of single-variable extremum-seeking controllers
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Solution Overview
Problem
Centralized multivariable extremum-seeking controllers for HVAC systems are difficult to implement, configure, and troubleshoot due to the need for knowledge of all channels, making them impractical for real-world applications.
Innovation Solution
The implementation of a HVAC system using multiple single-variable extremum-seeking controllers that independently perturb and modulate manipulated variables to optimize performance, allowing for decentralized control without requiring knowledge of the entire system's dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a centralized multivariable extremum-seeking controller is used to achieve multivariable optimization, then optimization performance is improved, but device complexity and ease of operation deteriorate due to the need for knowledge of all channels
Solution Approach 1:
The centralized multivariable controller is segmented into multiple independent single-variable ESCs, each responsible for one manipulated variable. This segmentation allows each controller to operate independently without requiring knowledge of other channels, thereby reducing overall system complexity while maintaining optimization capability through coordinated operation of all segments
2Productivity
If a centralized multivariable extremum-seeking controller is used to achieve multivariable optimization, then optimization performance is improved, but ease of operation deteriorates due to configuration and troubleshooting difficulty
Solution Approach 1:
By dividing the control system into independent single-variable ESC modules, configuration becomes simpler as each module can be tuned separately without affecting others. Troubleshooting is also easier since issues can be isolated to specific modules rather than searching through a complex centralized controller
3Device complexity
If single-variable ESCs are used independently for each manipulated variable, then device complexity is reduced, but measurement precision deteriorates due to inability to capture interactions between variables
Solution Approach 1:
An intermediary mechanism is introduced where each single-variable ESC estimates gradients based on local measurements of its own manipulated variable and the shared controlled variable. This intermediary gradient estimation approach allows independent operation while still capturing the effective influence of each variable on the controlled output
4Ease of operation
If decentralized single-variable ESCs are used, then ease of operation is improved through simpler tuning, but loss of information increases due to lack of global system knowledge
Solution Approach 1:
Each single-variable ESC performs self-service by independently estimating its own gradient through local experimentation and feedback. This self-service capability eliminates the need for global system information while maintaining effective control, as each controller adapts based on its own interactions with the controlled variable
Data Source
AI summary
A HVAC system for a building includes a plant and a plurality of single-variable extremum-seeking controllers (ESCs). The plant includes HVAC equipment operable to affect an environmental condition in the building. Each of the single-variable ESCs is configured to perturb a different manipulated variable with a different excitation signal and provide the manipulated variables as perturbed inputs to the plant. The plant uses multiple perturbed inputs to concurrently affect a performance variable. The single-variable ESCs are configured to estimate a gradient of the performance variable with respect to the each manipulated variable and independently drive the gradients toward zero by independently modulating the manipulated variables.