Method and devices for controlling a flow control system
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Solution Overview
Problem
Existing HVAC systems face inefficiencies in controlling fluid flow through thermal energy exchangers due to nonlinear transfer characteristics and dynamic changes, leading to inconsistent control performance across the operating range of actuated valves.
Innovation Solution
A flow control system that includes an electronic circuit to determine and utilize installed valve characteristics, combining feedforward and feedback control mechanisms to adjust fluid flow, accounting for pressure changes and nonlinearities, and implementing gain scheduling for adaptive control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fixed control parameters are used in linear feedback flow controllers, then the control system is simple to implement, but control performance becomes inconsistent across the entire operating range of actuated valves and thermal energy exchangers
Solution Approach 1:
The patent implements adaptive control that dynamically adjusts control parameters based on real-time operating conditions. The system continuously learns and updates the valve characteristics and thermal energy exchanger performance, transforming the static control approach into a dynamic one that adapts to changing conditions, thereby maintaining consistent control performance across the entire operating range.
Solution Approach 2:
The patent changes the control parameters adaptively based on the operating point. By monitoring actual flow and thermal energy exchange rates, the system adjusts control parameters to match the current operating conditions of the valve and thermal energy exchanger, resolving the contradiction between simple implementation and consistent performance.
2Measurement precision
If setpoint conditioning is used to account for nonlinear transfer characteristics, then control accuracy improves, but the system complexity increases due to additional conditioning requirements
Solution Approach 1:
The patent employs feedback mechanisms where the actual flow and thermal energy exchange rates are continuously measured and used to adjust the control output. This feedback loop automatically compensates for nonlinear transfer characteristics without requiring complex pre-conditioning of setpoints, as the system adapts in real-time based on actual performance.
Solution Approach 2:
The control system performs self-characterization by automatically learning the valve and thermal energy exchanger characteristics during operation. This self-service approach eliminates the need for manual setup or complex pre-programming of conditioning parameters, reducing system complexity while maintaining high control accuracy through adaptive learning.
Data Source
Figure 1~1a
Figure 2
Figure 3
AI summary
For controlling in an HVAC system (1) a flow control system (3), which comprises an actuated valve (V) for adjusting the flow of fluid (Φ) in a fluid transport circuit (10) of the HVAC system (1), an electronic circuit (20) receives (S1) and stores (S2), during operation of the flow control system (3), a plurality of flow values (m) measured in the fluid transport circuit (10) by a flow sensor (S) for respective valve positions of the actuated valve (V). During operation of the flow control system (3), the electronic circuit (20) determines, installed valve characteristics of the actuated valve (V) as installed in the HVAC system (1), using the plurality of flow values (m) for the respective valve positions. The electronic circuit (20) uses the installed valve characteristics to control the actuated valve (V) for adjusting the flow of fluid (Φ) in the fluid transport circuit (10).