Building management system with triggered feedback set-point signal for persistent excitation
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Solution Overview
Problem
Actuator saturation in building control systems leads to inaccurate predictive models, as it compromises the quality of data used for system identification, resulting in suboptimal control decisions.
Innovation Solution
An environmental control system that includes HVAC equipment with a processing circuit to monitor temperature tracking errors and heat transfer values, determining if the HVAC equipment is in a saturation region and adjusting the temperature setpoint to prevent saturation, thereby gathering accurate training data for predictive modeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the HVAC equipment operates at extreme positions (minimum or maximum load) to achieve persistent excitation for system identification, then the model accuracy improves, but actuator saturation occurs leading to data quality degradation
Solution Approach 1:
The system continuously monitors the HVAC equipment position and temperature tracking error, using this feedback to detect saturation conditions and trigger setpoint adjustments. The feedback loop ensures that when saturation is detected, the system responds by modifying the setpoint to drive the equipment out of the saturation region, thereby maintaining data quality while still achieving sufficient excitation for accurate modeling.
Solution Approach 2:
The system dynamically changes the temperature setpoint parameter based on detected saturation conditions. When saturation is identified through monitoring temperature tracking errors and equipment position, the setpoint is adjusted to a new value that drives the HVAC equipment out of the saturation region, allowing the system to collect high-quality data across different operating conditions without persistent saturation.
2Reliability
If the temperature setpoint is adjusted frequently to prevent actuator saturation, then data quality improves, but system complexity increases
Solution Approach 1:
The system performs preliminary detection of saturation conditions by monitoring temperature tracking errors and equipment position before saturation fully degrades data quality. By detecting saturation early and triggering setpoint adjustments proactively, the system prevents data quality degradation rather than reacting after the fact, simplifying the overall control logic while maintaining high data quality.
Solution Approach 2:
The system uses its own operational data (temperature tracking errors and equipment position) to detect saturation conditions and trigger corrective setpoint adjustments. This self-monitoring and self-correction mechanism eliminates the need for external complex control systems, allowing the HVAC controller to autonomously maintain data quality without adding significant system complexity.
3Measurement precision
If the system monitors temperature tracking error and heat transfer value continuously to detect saturation, then saturation detection accuracy improves, but energy consumption increases
Solution Approach 1:
The system implements continuous monitoring of temperature tracking error and heat transfer value, which represents excessive action beyond minimal requirements. This ensures high saturation detection accuracy but comes at the cost of increased energy consumption. The monitoring is performed at every control cycle to maintain precise detection of saturation conditions.
Data Source
AI summary
An environmental control system for a building including heating, ventilation, or air conditioning (HVAC) equipment that operates to affect a temperature of a zone of the building. The system includes a temperature sensor to measure the temperature and a controller including a processing circuit. The processing circuit is configured to operate the HVAC equipment based on a temperature setpoint and gather training data indicating system dynamics. The processing circuit is configured to monitor a temperature tracking error of the zone and a heat transfer value of the HVAC equipment and determine if the HVAC equipment is in a saturation region based on the temperature tracking error and the heat transfer value. The processing circuit is configured to, in response to a determination that the HVAC equipment is in the saturation region, calculate an adjusted temperature setpoint and operate the HVAC equipment based on the adjusted temperature setpoint.