Method and system for controlling outlet temperature of trough type solar thermal collector

Abstract

The invention relates to a trough type solar thermal collector outlet temperature control method and system, and belongs to the field of temperature control, and the method comprises the steps: constructing a trough type solar thermal collector outlet temperature mathematical model; performing Laplace transformation on the mathematical model of the outlet temperature of the trough type solar thermal collector to obtain a transfer function of the volume flow of the heat transfer working medium to the outlet temperature of the trough type solar thermal collector; determining a transfer function of an IMCPID controller according to a transfer function of the volume flow of the heat transfer working medium to the outlet temperature of the trough solar heat collector; according to the transfer function of the IMCPID controller, a target transfer function of the volume flow of the heat transfer working medium to the outlet temperature of the trough solar heat collector is determined; generating a feedback signal of the IMCPID controller according to a target transfer function of the volume flow of the heat transfer working medium to the outlet temperature of the trough solar heat collector; and according to the feedback signal, the temperature of an outlet of the trough type solar heat collector is controlled through the IMCPID controller.

Description

Technical Field

[0001] The invention belongs to the field of temperature control, and in particular relates to a method and system for controlling the outlet temperature of a trough type solar collector. Background Art

[0002] With the widespread application of solar energy as a clean and renewable energy source, trough solar thermal power stations have become one of the important energy production methods. In these power stations, the stability of the collector outlet temperature is crucial to ensure the safe and efficient operation of the power station. Too high or too low outlet temperature will not only affect the operating efficiency of the system, but may also cause equipment damage or even safety accidents.

[0003] In the prior art, the outlet temperature of a parabolic trough solar collector is usually controlled by adjusting the flow rate of a circulating heat transfer medium. The flow rate of the heat transfer medium is used as the regulating variable, and the outlet temperature is used as the regulated variable. However, due to the large uncertainty of solar radiation intensity and its changes over time, the control of the collector outlet temperature faces great challenges.

[0004] When dealing with trough solar collector systems with large time lag and inertia, traditional PID control algorithms will experience slow temperature regulation response, control oscillation, and easy overshoot, resulting in unsatisfactory temperature control effects. Summary of the invention

[0005] In view of the above deficiencies in the prior art, the purpose of the invention is to provide a trough solar collector outlet temperature control method and system, which can obtain the transfer function of the volume flow rate of the heat transfer medium to the trough solar collector outlet temperature by performing Laplace transform on the constructed mathematical model of the trough solar collector outlet temperature, so as to determine the transfer function of the IMC_PID controller, and determine the target transfer function of the volume flow rate of the heat transfer medium to the trough solar collector outlet temperature according to the transfer function of the IMC_PID controller, so as to generate a feedback signal of the IMC_PID controller, and control the trough solar collector outlet temperature through the IMC_PID controller, so that when dealing with a trough solar collector system with large time lag and inertia, there will be no slow temperature regulation response, control oscillation, and easy overshoot, and the temperature control effect will be more ideal.

[0006] In a first aspect of the present invention, a method for controlling the outlet temperature of a trough solar collector is provided, comprising:

[0007] S1, construct the mathematical model of the outlet temperature of trough solar collector;

[0008] S2, performing Laplace transformation on the mathematical model of the outlet temperature of the trough solar thermal collector to obtain a transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar thermal collector;

[0009] S3, determining a transfer function of an IMC_PID controller according to a transfer function of the volume flow rate of the heat transfer medium to an outlet temperature of the trough solar collector;

[0010] S4, determining a target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector according to the transfer function of the IMC_PID controller;

[0011] S5, obtaining the actual outlet temperature of the trough solar collector;

[0012] S6, setting the target outlet temperature of the trough solar collector;

[0013] S7, generating a feedback signal of the IMC_PID controller according to a target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector;

[0014] S8, controlling the outlet temperature of the trough solar collector through the IMC_PID controller according to the feedback signal.

[0015] Furthermore, the S1 is specifically:

[0016] According to the following formula, the mathematical model of the outlet temperature of the trough solar collector is constructed:

[0017]

[0018] Among them, ρ HTF Indicates the density of the heat transfer medium, C HTF represents the specific heat capacity of the heat transfer medium, A represents the inner surface area of ​​the heat absorption tube, represents the partial derivative, T n represents the outlet temperature of the nth trough solar collector, t represents the time, η opt represents the optical efficiency of the parabolic trough solar collector, I DNI represents the direct solar radiation intensity, w represents the width of the trough solar collector, △X represents the unit length of the trough solar collector, represents the volume flow rate of the heat transfer medium, T n-1 represents the outlet temperature of the n-1th trough solar collector, h f Denotes the convective heat transfer coefficient, D abs,in Indicates the inner diameter of the heat absorption tube, T a Indicates the ambient temperature.

[0019] Furthermore, the S2 is specifically:

[0020] According to the following formula, the mathematical model of the outlet temperature of the trough solar thermal collector is Laplace transformed to obtain the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar thermal collector:

[0021]

[0022] Among them, G m () represents the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, s represents the Laplace transform variable, represents the volume flow rate of the heat transfer medium after Laplace transformation, represents the outlet temperature of the nth trough solar collector after Laplace transformation, and e represents the base of the natural logarithm.

[0023] Furthermore, the S3 is specifically:

[0024] Determine the transfer function of the IMC_PID controller according to the following formula:

[0025]

[0026] Where C() represents the transfer function of the IMC_PID controller, s represents the Laplace transform variable, K represents the proportional coefficient, T i Indicates the integration time, T d represents the differential time, and α represents a constant.

[0027] Furthermore, the proportionality coefficient is specifically:

[0028]

[0029] Among them, K represents the proportionality coefficient, T i Indicates the integration time, K p represents the process gain, T f represents the filtering time constant, τ represents the delay time;

[0030] The integration time is specifically:

[0031]

[0032] Among them, T represents the total duration;

[0033] The differential time is specifically:

[0034]

[0035] Among them, T d Indicates the derivative time.

[0036] Furthermore, the value range of the constant α is 0.005 to 1.

[0037] Furthermore, the S4 is specifically:

[0038] According to the following formula, the target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector is determined:

[0039]

[0040] in, The target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector is represented by K p represents process gain, T represents total time, s represents Laplace transform variable, e represents the base of natural logarithm, and τ represents delay time.

[0041] Further, the S7 is specifically:

[0042] The feedback signal of the IMC_PID controller is generated according to the following formula:

[0043]

[0044] in, represents the feedback signal of the IMC_PID controller, s represents the Laplace transform variable, G m () represents the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, represents the target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, U() represents the output of the IMC_PID controller, G d () represents the transfer function of the disturbance channel.

[0045] Furthermore, the S8 is specifically:

[0046]

[0047] Where Y() represents the outlet temperature of the trough solar collector after being controlled by the IMC_PID controller, s represents the Laplace transform variable, G IMC () represents the transfer function of the internal model controller, G m () represents the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, represents the target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, R() represents the given value transfer function, G d () represents the transfer function of the disturbance channel.

[0048] A second aspect of the present invention provides a trough solar collector outlet temperature control system, comprising: a memory and one or more processors;

[0049] One or more application programs are stored in the memory, and the one or more application programs are suitable for being executed by the one or more processors to implement the above-mentioned method for controlling the outlet temperature of the trough solar collector.

[0050] The beneficial effects of the present invention are as follows:

[0051] The method and system of the present invention perform Laplace transform on the constructed mathematical model of the outlet temperature of the trough solar collector to obtain the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, so as to determine the transfer function of the IMC_PID controller. According to the transfer function of the IMC_PID controller, the target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector is determined to generate a feedback signal of the IMC_PID controller, and the outlet temperature of the trough solar collector is controlled by the IMC_PID controller. When dealing with a trough solar collector system with large time lag and inertia, the phenomenon of slow temperature regulation response, control oscillation and easy overshoot will not occur, and the temperature control effect is more ideal. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings are only used to illustrate specific embodiments and are not considered to limit the present invention. In the entire drawings, the same reference symbols represent the same components. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0053] Figure 1 A schematic flow chart of a method for controlling outlet temperature of a trough type solar thermal collector provided by an embodiment of the present invention;

[0054] Figure 2 A schematic structural diagram of a trough solar collector outlet temperature control system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work should fall within the scope of protection of the present invention.

[0056] Furthermore, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts disclosed in the present invention.

[0057] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. The terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of methods and systems consistent with some aspects of the present invention as detailed in the appended claims.

[0059] The present invention proposes a trough solar collector outlet temperature control method and system, which solves the technical problem that the traditional PID control algorithm in the prior art will have slow temperature regulation response, control oscillation, and easy overshoot when dealing with a trough solar collector system with large time lag and inertia, resulting in unsatisfactory temperature control effect.

[0060] Method Embodiment

[0061] Reference Manual Attached Figure 1 , showing a schematic flow chart of a method for controlling the outlet temperature of a trough type solar collector provided in an embodiment of the present invention.

[0062] An embodiment of the present invention provides a method for controlling the outlet temperature of a trough solar collector, comprising:

[0063] Specifically, the method includes steps S1 to S8.

[0064] S1, construct a mathematical model of the outlet temperature of a trough solar collector.

[0065] In the present invention, the mathematical model is constructed to accurately describe the thermodynamic behavior of the trough solar collector, and the outlet temperature of the collector can be predicted and controlled more accurately, thereby improving the control accuracy of the overall system. Through accurate model analysis, a reasonable basis can be provided for the design of the controller, making the temperature control more efficient and avoiding excessive or insufficient regulation.

[0066] In a possible implementation manner, S1 specifically includes:

[0067] According to the following formula, the mathematical model of the outlet temperature of the trough solar collector is constructed:

[0068]

[0069] Among them, ρ HTF Indicates the density of the heat transfer medium, C HTF represents the specific heat capacity of the heat transfer medium, A represents the inner surface area of ​​the heat absorption tube, represents the partial derivative, T n represents the outlet temperature of the nth trough solar collector, t represents the time, η opt represents the optical efficiency of the parabolic trough solar collector, I DNI represents the direct solar radiation intensity, w represents the width of the trough solar collector, △X represents the unit length of the trough solar collector, represents the volume flow rate of the heat transfer medium, T n-1 represents the outlet temperature of the n-1th trough solar collector, h f Denotes the convective heat transfer coefficient, D abs,in Indicates the inner diameter of the heat absorption tube, T a Indicates the ambient temperature.

[0070] In the present invention, through this mathematical model, various parameters of the trough solar collector can be adjusted and optimized, such as how to adjust the heat transfer fluid flow rate to achieve the best outlet temperature control. This helps to improve the overall efficiency of the collector and reduce energy waste. The use of this mathematical model provides a theoretical basis for subsequent control strategies (such as IMC_PID controller). Through precise mathematical modeling, it can be ensured that the controller design is based on the actual physical process, thereby improving the control effect, avoiding blind adjustment, and enhancing the stability and reliability of the system. The model can be adaptively adjusted according to changes in external conditions such as different solar radiation intensity, ambient temperature, heat transfer fluid flow rate, etc., to ensure that the system can operate stably under a variety of operating conditions.

[0071] S2, Laplace transform is performed on the mathematical model of the outlet temperature of the trough solar collector to obtain the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector.

[0072] In the present invention, these differential equations in the time domain can be converted into algebraic equations through Laplace transform, thereby simplifying the analysis process. Laplace transform converts the time-dependent dynamic system into a system in the frequency domain or complex plane, which helps to analyze the behavior of the system more intuitively. After Laplace transform, the dynamic characteristics of the system can be expressed in the form of transfer function. Through the transfer function, the response characteristics of the system, such as steady-state gain, time constant, stability of the system, etc., can be clearly understood, providing strong support for subsequent controller design (such as IMC_PID controller).

[0073] It should be noted that the transfer function is a mathematical model that describes the relationship between the input and output of a linear time-invariant system. Through the transfer function, we can understand the response of the system to the input signal, so as to design a controller that meets the requirements and achieve system stability and performance optimization. In addition, the transfer function can help analyze the dynamic characteristics of the system, help evaluate the stability and dynamic response characteristics of the system, and provide an important reference for system design and debugging.

[0074] In a possible implementation manner, S2 is specifically:

[0075] According to the following formula, the mathematical model of the outlet temperature of the trough solar collector is Laplace transformed to obtain the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector:

[0076]

[0077] Among them, G m () represents the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, s represents the Laplace transform variable, represents the volume flow rate of the heat transfer medium after Laplace transformation, represents the outlet temperature of the nth trough solar collector after Laplace transformation, and e represents the base of the natural logarithm.

[0078] In the present invention, Laplace transform converts the differential equation in the time domain into an algebraic equation in the frequency domain, which simplifies the analysis and design of the system. For complex dynamic systems, Laplace transform enables control engineers to understand the dynamic response characteristics of the system more intuitively. The form of transfer function can directly describe the relationship between the input and output of the system, helping to simplify the temperature control design of the trough solar collector. The transfer function after Laplace transform shows the dynamic relationship between the volume flow rate of the heat transfer medium and the outlet temperature. This transfer function can not only describe the stability of the system, but also reveal the response characteristics of the system on different time scales.

[0079] S3, determining the transfer function of the IMC_PID controller according to the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector.

[0080] It should be noted that the IMC_PID controller is an advanced control system that combines the internal model controller (IMC) strategy with proportional-integral-derivative (PID) control logic. The internal model control strategy designs the controller based on an accurate process model, which can predict and compensate the system response, thereby improving control accuracy and stability. The main advantage of IMC is that it can effectively handle model errors and external disturbances and optimize system performance through feedback mechanisms. When internal model control is combined with a PID controller, it not only retains the simplicity and intuitiveness of the PID controller, which is widely used in industrial applications, but also greatly improves the control system's regulation performance and robustness for complex dynamic systems with the help of IMC's model prediction and error compensation capabilities. IMC_PID controllers are usually used in industrial processes that require fast and precise regulation and have large time lags or high inertia to achieve better control effects and system stability.

[0081] Among them, the internal model controller (IMC) is a model-based control strategy that designs control systems by building an accurate mathematical model of the process. The core idea of ​​the IMC strategy is to directly use this process model in the controller design to predict and compensate for the system behavior, thereby achieving precise control of the system output. This control method is particularly effective in dealing with systems with significant time delays and complex dynamic characteristics, because it can accurately predict the future system behavior, thereby maintaining the stability and performance of the system in the presence of disturbances and model uncertainties. IMC is widely used in industries such as chemical, petroleum refining, aerospace, and high-tech manufacturing to optimize control quality and simplify the design and implementation of control systems.

[0082] Among them, the PID controller is a widely used feedback control system, and its name comes from the initials of the three operations of proportional, integral, and derivative. The PID controller measures the error between the actual output of the system and the expected output (set value), and uses this error to perform proportional, integral, and differential operations to generate a control signal to adjust the input of the system. Proportional control provides a response proportional to the current error, integral control considers the accumulation of errors to eliminate steady-state errors, and derivative control responds to the rate of change of the error and is used to predict the future trend of the error, thereby improving the dynamic performance and stability of the system. The PID controller has become the most common control algorithm in industrial automation due to its simple structure, convenient adjustment, and wide applicability.

[0083] In the present invention, the IMC_PID controller is combined with the internal model control and PID control to maintain high system stability in the presence of model errors and external disturbances. The internal model control helps predict and compensate for future system behavior, while the PID control ensures that the temperature is stable near the expected value by adjusting the feedback in real time. This combination can better cope with the nonlinear characteristics, delays and time-varying factors of the system, and enhances the system's adaptability to environmental changes.

[0084] In a possible implementation, S3 is specifically:

[0085] Determine the transfer function of the IMC_PID controller according to the following formula:

[0086]

[0087] Where C() represents the transfer function of the IMC_PID controller, s represents the Laplace transform variable, K represents the proportional coefficient, T i Indicates the integration time, T d represents the differential time, and α represents a constant.

[0088] The specific proportionality coefficient is:

[0089]

[0090] Among them, K represents the proportionality coefficient, T i Indicates the integration time, K p represents the process gain, T f represents the filtering time constant, and τ represents the delay time.

[0091] The specific integration time is:

[0092]

[0093] Among them, T represents the total duration.

[0094] The specific differential time is:

[0095]

[0096] Among them, T d Indicates the derivative time.

[0097] It should be noted that the value range of the constant α is 0.005 to 1.

[0098] Optionally, in the present invention, the value of the constant α is 0.05.

[0099] In the present invention, the MC_PID controller combines the model prediction capability of internal model control (IMC) and the feedback control advantage of PID. By accurately calculating the proportional coefficient, integral time and differential time, it can be ensured that the system not only has a fast response when adjusting the temperature, but also maintains stability in the face of disturbances or system errors. By optimizing the integral time and differential time, the control system can respond quickly to external disturbances and maintain the lowest error in steady state. Reasonable selection of constants can ensure that the differential action is effective in regulating the system dynamics and avoid noise amplification caused by excessive differentiation.

[0100] S4, determining a target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector according to the transfer function of the IMC_PID controller.

[0101] In the present invention, by determining the target transfer function, the relationship between the heat transfer medium flow rate and the outlet temperature of the trough solar collector can be accurately described, so that the control system can accurately adjust the heat transfer medium flow rate, thereby achieving accurate control of the target temperature. After determining the target transfer function, the feedback control system can be better designed. This allows the IMC_PID controller to adjust according to the target transfer function, ensuring that the temperature change of the trough solar collector can quickly and smoothly reach the expected target state. Through this precise target setting, the system can avoid over-adjustment or lag, and improve the response speed and stability of temperature control.

[0102] In a possible implementation manner, S4 is specifically:

[0103] According to the following formula, the target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector is determined:

[0104]

[0105] in, The target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector is represented by K prepresents process gain, T represents total time, s represents Laplace transform variable, e represents the base of natural logarithm, and τ represents delay time.

[0106] In the present invention, after the target transfer function is determined, the control system (such as IMC_PID controller) can be optimized according to the target transfer function. During design, the system can accurately calculate the parameters of the controller (such as proportional coefficient, integral time, differential time) according to the gain and time constant of the target transfer function, so as to achieve faster and more accurate temperature regulation. The controller can adjust the flow rate of the heat transfer medium in real time according to the characteristics of the target transfer function to ensure that the system always maintains an ideal working state. By clarifying the target transfer relationship between the volume flow rate of the heat transfer medium and the outlet temperature, the system can better cope with external disturbances and changes.

[0107] S5, obtaining the actual outlet temperature of the trough solar collector.

[0108] S6, setting the target outlet temperature of the trough solar collector.

[0109] S7, generating a feedback signal of the IMC_PID controller according to a target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector.

[0110] In the present invention, by generating the feedback signal of the IMC_PID controller, the control system can accurately adjust the heat transfer medium flow rate according to the target transfer function, thereby achieving high-precision control of the outlet temperature of the trough solar collector. Generating feedback signals and adjusting them in real time can effectively reduce the response time of the system. Accurate feedback control can ensure that the temperature of the trough solar collector is always kept within the ideal range, avoiding overheating or underheating, thereby reducing energy waste.

[0111] In a possible implementation manner, S7 specifically includes:

[0112] The feedback signal of the IMC_PID controller is generated according to the following formula:

[0113]

[0114] in, represents the feedback signal of the IMC_PID controller, s represents the Laplace transform variable, G m () represents the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, represents the target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, U() represents the output of the IMC_PID controller, G d () represents the transfer function of the disturbance channel.

[0115] It should be noted that when G m (s) is exactly equal to And there is no external disturbance G d When (s) = 0, It means that it is in an open-loop structure and there is no need to further control the outlet temperature of the trough solar collector.

[0116] Furthermore, when in a closed-loop structure, the outlet temperature of the trough solar collector is controlled through step S8.

[0117] In the present invention, by ensuring that the system does not need to be controlled when in an open-loop state, energy can be effectively saved and over-adjustment or overheating can be avoided. The temperature control of the solar collector will automatically enter the open-loop mode when the system is undisturbed and working normally, without the need for frequent adjustments, thereby reducing energy consumption. The system can flexibly switch between different working states, accurately control through a closed-loop structure when there are external disturbances or temperature errors, and reduce invalid adjustments through an open-loop structure when the system behavior is stable. Through this flexible adjustment, the efficiency of the control system is optimized, which not only improves the response speed, but also avoids unnecessary adjustments, thereby improving the overall control performance.

[0118] S8, according to the feedback signal, the outlet temperature of the trough solar collector is controlled through the IMC_PID controller.

[0119] In the present invention, the IMC_PID controller adjusts the volume flow rate of the heat transfer medium in real time through the feedback signal, thereby ensuring that the outlet temperature of the trough solar collector is stable near the set value. The feedback mechanism can respond immediately to the difference between the actual temperature and the target temperature, correct any temperature fluctuations, ensure that the system temperature remains accurate, and avoid excessively high or low temperatures. External disturbances (such as fluctuations in solar radiation intensity, changes in ambient temperature, etc.) can affect the temperature of the collector. The IMC_PID controller quickly adjusts the control strategy based on the feedback signal, and can quickly respond to these disturbances, ensuring that the outlet temperature of the trough solar collector is not significantly affected by external changes, thereby maintaining the stability and efficiency of the system.

[0120] In a possible implementation manner, S8 specifically includes:

[0121]

[0122] Where Y() represents the outlet temperature of the trough solar collector after being controlled by the IMC_PID controller, s represents the Laplace transform variable, G IMC () represents the transfer function of the internal model controller, G m () represents the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, represents the target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, R() represents the given value transfer function, G d () represents the transfer function of the disturbance channel.

[0123] It should be noted that the given value transfer function represents the target output or expected response of the system in the control system, and is the ideal output behavior preset when the controller is designed.

[0124] It should be noted that the transfer function of the inner loop feedback controller in the internal model controller (IMC) is specifically:

[0125]

[0126] Where C' represents the transfer function of the inner loop feedback controller, s represents the Laplace transform variable, G IMC () represents the transfer function of the internal model controller, The target transfer function represents the volume flow rate of the heat transfer medium to the outlet temperature of the parabolic trough solar collector.

[0127] In the present invention, the design of IMC is based on an accurate system model. Through the feedback mechanism of the internal model controller, the system can make precise adjustments based on the error between the actual heat transfer fluid flow rate and the target transfer function. This design can effectively reduce the error caused by external disturbances, thereby improving the stability and control accuracy of the system. By combining internal model control with PID control strategy, the controller can automatically adjust the control parameters according to real-time feedback signals. In this way, the IMC_PID controller can be adaptively adjusted to cope with changes under different working conditions. Whether facing rapidly changing ambient temperature or temperature fluctuations caused by changes in fluid flow rate, the control system can flexibly adjust the temperature control strategy to ensure efficient and stable operation of the system.

[0128] System Example

[0129] Reference Manual Attached Figure 2 , showing a schematic structural diagram of a trough solar collector outlet temperature control system provided in an embodiment of the present invention.

[0130] The present invention provides a trough solar collector outlet temperature control system 30 , comprising: a memory 303 and one or more processors 301 .

[0131] One or more application programs are stored in the memory 303 , and the one or more application programs are suitable for being executed by the one or more processors 301 to implement the outlet temperature control method of the trough solar collector described in the method embodiment.

[0132] The trough solar collector outlet temperature control system 30 comprises: a processor 301 and a memory 303. The processor 301 and the memory 303 are connected, for example, via a bus 302.

[0133] The structure of the trough solar collector outlet temperature control system 30 does not constitute a limitation on the embodiment of the present invention.

[0134] Processor 301 may be a CPU, a general purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, a transistor logic device, a hardware component or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of the present invention. Processor 301 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0135] The bus 302 may include a path to transmit information between the above components. The bus 302 may be a PCI bus or an EISA bus, etc. The bus 302 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus.

[0136] The memory 303 can be a ROM or other type of static storage device that can store static information and instructions, a RAM or other type of dynamic storage device that can store information and instructions, or an EEPROM, a CD-ROM or other optical disk storage, an optical disk storage (including a compressed optical disk, a laser disk, an optical disk, a digital versatile disk, a Blu-ray disk, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited to these.

[0137] Computer Readable Storage Medium Embodiments

[0138] The present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program can be loaded and executed by a processor to implement the method for controlling the outlet temperature of a trough solar thermal collector as described in the first aspect.

[0139] The applicant of the present invention has made a detailed explanation and description of the implementation examples of the present invention in conjunction with the drawings in the specification. However, those skilled in the art should understand that the above implementation examples are only preferred implementation schemes of the present invention, and the detailed description is only to help readers better understand the spirit of the present invention, but not to limit the scope of protection of the present invention. On the contrary, any improvements or modifications based on the inventive spirit of the present invention should fall within the scope of protection of the present invention.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Any changes or replacements that can be easily thought of by those skilled in the art within the technical scope disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for controlling the outlet temperature of a trough solar collector, characterized in that: include: S1, construct the mathematical model of the outlet temperature of trough solar collector; S2, performing Laplace transformation on the mathematical model of the outlet temperature of the trough solar thermal collector to obtain a transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar thermal collector; S3, determining a transfer function of an IMC_PID controller according to a transfer function of the volume flow rate of the heat transfer medium to an outlet temperature of the trough solar collector; S4, determining a target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector according to the transfer function of the IMC_PID controller; S5, obtaining the actual outlet temperature of the trough solar collector; S6, setting the target outlet temperature of the trough solar collector; S7, generating a feedback signal of the IMC_PID controller according to a target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector; S8, controlling the outlet temperature of the trough solar collector through the IMC_PID controller according to the feedback signal.

2. The method for controlling the outlet temperature of a trough solar collector according to claim 1, characterized in that: The S1 is specifically: According to the following formula, the mathematical model of the outlet temperature of the trough solar collector is constructed: Among them, ρ HTF Indicates the density of the heat transfer medium, C HTF represents the specific heat capacity of the heat transfer medium, A represents the inner surface area of ​​the heat absorption tube, represents the partial derivative, T n represents the outlet temperature of the nth trough solar collector, t represents the time, η opt represents the optical efficiency of the parabolic trough solar collector, I DNI represents the direct solar radiation intensity, w represents the width of the trough solar collector, △X represents the unit length of the trough solar collector, represents the volume flow rate of the heat transfer medium, T n-1 represents the outlet temperature of the n-1th trough solar collector, h f Denotes the convective heat transfer coefficient, D abs,in Indicates the inner diameter of the heat absorption tube, T a Indicates the ambient temperature.

3. The method for controlling outlet temperature of a trough solar collector according to claim 1, characterized in that: The S2 is specifically: According to the following formula, the mathematical model of the outlet temperature of the trough solar thermal collector is Laplace transformed to obtain the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar thermal collector: Among them, G m () represents the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, s represents the Laplace transform variable, represents the volume flow rate of the heat transfer medium after Laplace transformation, represents the outlet temperature of the nth trough solar collector after Laplace transformation, and e represents the base of the natural logarithm.

4. The method for controlling the outlet temperature of a trough solar collector according to claim 1, characterized in that: The S3 is specifically: Determine the transfer function of the IMC_PID controller according to the following formula: Where C() represents the transfer function of the IMC_PID controller, s represents the Laplace transform variable, K represents the proportional coefficient, T i Indicates the integration time, T d represents the differential time, and α represents a constant.

5. The method for controlling the outlet temperature of a trough solar collector according to claim 4, characterized in that: The specific proportionality coefficient is: Among them, K represents the proportionality coefficient, T i Indicates the integration time, K p represents the process gain, T f represents the filtering time constant, τ represents the delay time; The integration time is specifically: Among them, T represents the total duration; The differential time is specifically: Among them, T d Indicates the derivative time.

6. The method for controlling the outlet temperature of a trough solar collector according to claim 4, characterized in that: The value range of the constant α is 0.005 to 1.

7. The method for controlling outlet temperature of a trough solar collector according to claim 1, characterized in that: The S4 is specifically: According to the following formula, the target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector is determined: in, The target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector is represented by K p represents process gain, T represents total time, s represents Laplace transform variable, e represents the base of natural logarithm, and τ represents delay time.

8. The method for controlling outlet temperature of a trough solar collector according to claim 1, characterized in that: The S7 is specifically: The feedback signal of the IMC_PID controller is generated according to the following formula: in, represents the feedback signal of the IMC_PID controller, s represents the Laplace transform variable, G m () represents the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, represents the target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, U() represents the output of the IMC_PID controller, G d () represents the transfer function of the disturbance channel.

9. The method for controlling outlet temperature of a trough solar collector according to claim 1, characterized in that: The S8 is specifically: Where Y() represents the outlet temperature of the trough solar collector after being controlled by the IMC_PID controller, s represents the Laplace transform variable, G IMC () represents the transfer function of the internal model controller, G m () represents the transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, represents the target transfer function of the volume flow rate of the heat transfer medium to the outlet temperature of the trough solar collector, R() represents the given value transfer function, G d () represents the transfer function of the disturbance channel.

10. A trough solar collector outlet temperature control system, characterized in that: include: memory and one or more processors; One or more application programs are stored in the memory, and the one or more application programs are suitable for being executed by the one or more processors to implement the outlet temperature control method of the trough solar collector according to any one of claims 1 to 9.

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