Solar Thermal Plant Fuzzy Control for Stable Outlet Temperature
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Solution Overview
Problem
Solar thermal power plants face challenges in maintaining stable output temperatures under transient solar radiation conditions, leading to fluctuations and inefficiencies.
Innovation Solution
A fuzzy logic control method that records and processes input parameters such as time of day, outlet temperature, and solar irradiation conditions to generate output parameters for controlling the inlet valve and solar collector focusing, ensuring robust and adaptive control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional control methods are used to maintain output temperature, then the control system is simple, but the output temperature fluctuates under transient solar radiation conditions
Solution Approach 1:
The patent applies parameter changes by transforming crisp input parameters (temperature, solar irradiation, valve position) into fuzzy sets with membership functions. This allows the control system to handle transient solar radiation conditions more effectively by representing parameters as ranges rather than fixed values, thereby improving output temperature stability without requiring a fundamentally complex system architecture.
Solution Approach 2:
The patent implements feedback through a closed-loop fuzzy logic control system that continuously monitors output temperature and adjusts the inlet valve position accordingly. The control system uses feedback from temperature sensors and solar irradiation measurements to dynamically adjust valve opening, maintaining stable output temperature despite varying solar conditions.
2Stability of the object's composition
If the inlet valve is dynamically adjusted to maintain temperature, then temperature stability improves, but the control response becomes slower under rapid solar radiation changes
Solution Approach 1:
The patent applies dynamics by making the control system adaptive to changing solar radiation conditions. The fuzzy logic controller dynamically adjusts its response based on the current operating state, using membership functions that can handle rapid transitions. This allows the system to respond quickly to solar radiation changes while maintaining temperature stability, as the controller can modulate valve position continuously rather than in fixed steps.
Solution Approach 2:
The patent uses parameter changes in the fuzzy logic rules to accelerate response time. By changing the membership function parameters and rule weights based on solar irradiation levels, the system can respond more aggressively to rapid solar changes when needed, while maintaining smooth control during stable conditions.
3Reliability
If fuzzy logic control is implemented to handle transient conditions, then robustness improves, but the device complexity increases
Solution Approach 1:
The patent implements parameter changes by using fuzzy logic to transform precise input measurements into linguistic variables with membership functions. This approach increases robustness by handling uncertainties and transient conditions more gracefully, while the complexity is managed through standardized fuzzy logic operations that can be implemented using off-the-shelf controllers and software libraries.
Data Source
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AI summary
A method is provided for open- and/or closed-loop control of a solar thermal power plant which comprises at least one unit with an input valve and with a solar collector, in which method: input parameters are measured for the at least one unit, said input parameters comprising (i) a time of day, (ii) a temperature which characterises an output temperature of heat transfer fluid at the at least one unit, (iii) a variable which characterises insolation conditions, and (iv) an input valve parameter which characterises an opening area at the input valve; the input parameters are assigned respective fuzzy set parameters according to a first rule set in a fuzzification device; an interference device links and evaluates the fuzzy set parameters according to a second rule set and fuzzy set result parameters are produced; and output parameters are produced from fuzzy set result parameters according to a third rule set in a defuzzification device, said output parameters comprising (i) an opening parameter which defines an opening of the input valve, and (ii) a focussing parameter which defines a focussing of the at least one solar collector.