Solar thermal power generation system

Abstract

The invention discloses a solar thermal power generation system which comprises a light condensation device, a heat absorber, a heat storage device, a generator set and a cooperative control module. The cooperative control module; a real-time data acquisition unit, a compensation strategy generation unit and a control instruction unit; according to the invention, through real-time fusion analysis of condensation intensity fluctuation, heat storage capacity dynamic and power grid frequency modulation requirements by the cooperative control module, a dynamic compensation mechanism based on photothermal conversion and electric energy output coupling characteristics is established, so that the heat energy release rate of the heat storage device is accurately matched with the power regulation requirements of the generator set; and the problem of unplanned charging and discharging of stored heat caused by sudden weather change in a traditional control method is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar thermal power generation, and particularly to a solar thermal power generation system. Background Art

[0002] A solar thermal power generation system is an energy conversion system that captures solar radiant energy through a concentrating device and converts it into heat energy, and then drives a generator set to output electric energy based on a thermodynamic cycle. Its core links include photothermal conversion, heat energy transfer, thermal energy storage regulation, and thermoelectric co-generation. Currently, mainstream solar thermal power generation systems generally adopt a closed-loop control strategy. For example, the flow rate of the heat transfer working fluid is adjusted through temperature feedback, the charging and discharging timing of the thermal energy storage device is optimized based on a prediction model, and the output of the generator set is dynamically adjusted in combination with the grid demand.

[0003] However, there are significant deficiencies in the existing technology in the dynamic cooperative control of photothermal conversion and power output: due to the instantaneous fluctuations of the concentrating intensity affected by weather conditions, it is difficult to match the heat energy input rate of the heat transfer working fluid with the thermoelectric conversion demand of the generator set in real time, resulting in the thermal energy storage device frequently being in an unplanned charging and discharging state. For example, when the concentrating intensity drops suddenly due to cloud cover, the system needs to quickly switch to the thermal energy storage release mode to maintain the stability of the power generation. However, the traditional control method relies on a fixed threshold to trigger thermal energy storage compensation and cannot dynamically generate a compensation strategy according to the real-time concentrating attenuation gradient, the remaining capacity of the thermal energy storage medium, and the grid frequency modulation demand, resulting in the premature depletion or excessive release of the thermal energy storage device, and further causing power generation fluctuations or even system shutdown protection. This defect in dynamic cooperative control has become a key technical bottleneck restricting the efficient and stable operation of solar thermal power generation systems under complex lighting conditions.

[0004] Therefore, it is necessary to propose a solar thermal power generation system to solve the above problems. Summary of the Invention

[0005] The present invention provides a solar thermal power generation system to solve the problem of the deficiency in the dynamic cooperative control of photothermal conversion and power output in the existing technology.

[0006] The present invention provides a solar thermal power generation system, including: a concentrating device, an absorber, a thermal energy storage device, a generator set, and a cooperative control module; the concentrating device is used to capture solar radiant energy and reflect it to the absorber; the absorber converts the received radiant energy into heat energy and transfers it to the heat transfer working fluid; the thermal energy storage device is connected to the absorber and the generator set through a heat transfer working fluid circuit and is used to store or release heat energy; the generator set converts heat energy into electric energy and outputs it to the grid; the cooperative control module includes:

[0007] a real-time data acquisition unit, which is used to collect the light intensity fluctuation data of the concentrating device, the remaining thermal energy storage capacity data of the thermal energy storage device, and the grid frequency modulation demand data.

[0008] A compensation strategy generation unit calculates a concentrating attenuation gradient based on the light intensity fluctuation data, and generates a dynamic compensation strategy by combining the remaining heat storage capacity data and the frequency modulation demand data;

[0009] A control instruction unit synchronously adjusts the charging and discharging rates of the heat storage device and the output power of the generator set according to the dynamic compensation strategy, so as to realize the dynamic matching of solar-thermal conversion and power output.

[0010] Furthermore, the compensation strategy generation unit fuses the concentrating attenuation gradient, the remaining heat storage capacity and the frequency modulation demand through a dynamic weight model, where: the dynamic weight model adjusts the heat storage compensation priority according to the real-time concentrating attenuation gradient. When the concentrating attenuation gradient exceeds a preset threshold, the compensation amount is preferentially generated based on the remaining heat storage capacity; when the power grid frequency modulation demand includes a power ramp rate constraint, the compensation rate of the heat storage device is dynamically reduced to match the power regulation margin of the generator set.

[0011] Furthermore, the compensation strategy generation unit further includes a fuzzy control rule base for dividing the triggering conditions of the compensation strategy according to the light intensity fluctuation level:

[0012] When the light intensity fluctuation level is at the first level, a combined compensation mode of the heat storage device and the generator set is adopted;

[0013] When the light intensity fluctuation level is at the second level, the compensation amount of the heat storage device is restricted and the power smoothing algorithm of the generator set is started; the light intensity fluctuation level is comprehensively determined according to the time derivative and the duration of the concentrating attenuation gradient.

[0014] Furthermore, the heat storage device includes at least two independent heat storage units, and the control instruction unit switches the charging and discharging modes of the heat storage units according to the dynamic compensation strategy:

[0015] When the concentrating intensity drops suddenly due to cloud occlusion, the heat energy of the high thermal conductivity heat storage unit is preferentially released to quickly respond to the power compensation demand; when the concentrating intensity recovers, the low thermal conductivity heat storage unit is switched to the charging mode to extend the heat storage duration.

[0016] Furthermore, the generator set includes a thermoelectric conversion efficiency feedback unit for monitoring the mapping relationship between the temperature of the working medium at the inlet of the steam turbine and the power generation in real time; the control instruction unit adjusts the output power setting value of the generator set according to the mapping relationship to minimize the deviation between the solar-thermal conversion efficiency and the power grid frequency modulation demand.

[0017] Furthermore, the heat storage device further includes a heat storage medium temperature monitoring unit for obtaining the axial temperature distribution of the heat storage medium in real time; the control instruction unit dynamically adjusts the charging and discharging rates according to the axial temperature distribution so that the thermal stress of the heat storage medium does not exceed a preset safety threshold.

[0018] Furthermore, the collaborative control module further includes a communication unit, which is used to transmit the light intensity fluctuation data, the remaining heat storage capacity data, and the frequency modulation demand data through 5G or optical fiber, and the data transmission delay is less than 50 ms.

[0019] Furthermore, the collaborative control module is communicatively connected to the power grid dispatching system, and is used to receive real-time electricity price signals and optimize the economic weight coefficient of the dynamic compensation strategy.

[0020] The present invention has the following beneficial effects: Through the real-time fusion analysis of the light intensity fluctuation, the dynamic heat storage capacity, and the power grid frequency modulation demand by the collaborative control module, the present invention establishes a dynamic compensation mechanism based on the coupling characteristics of the solar-thermal conversion and the electric energy output, enabling the heat release rate of the heat storage device to be accurately matched with the power regulation demand of the generator set, and effectively solving the problem of unplanned charging and discharging of the heat storage caused by sudden weather changes in the traditional control method. In the scenario of sudden change in light intensity, the system dynamically predicts the heat storage compensation demand and synchronously regulates the flow rate of the heat transfer working medium and the output of the generator set, significantly improving the response speed and stability of the solar-thermal-electricity conversion link, and avoiding the power oscillation and shutdown risks caused by premature depletion or excessive release of the heat storage; at the same time, combining the closed-loop control of the thermal stress distribution of the heat storage medium and the power grid frequency modulation demand, optimizing the utilization rate and life cycle of the heat storage unit, and reducing the energy loss and maintenance cost caused by frequent charging and discharging of the system. The present invention systematically improves the operation robustness and energy conversion efficiency of the solar thermal power generation system under complex illumination conditions from the dimension of dynamic collaborative control. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0022] Figure 1 Schematic diagram of the solar thermal power generation system provided by the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the specific embodiments and corresponding drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The technical solutions provided by each embodiment of the present invention will be described in detail below with reference to the drawings.

[0024] Please refer to Figure 1, a solar thermal power generation system provided by the present invention, includes a concentrating device, a heat absorber, a heat storage device, a generator set, and a cooperative control module.

[0025] The concentrating device uses a parabolic mirror or a heliostat array, and its function is to focus solar radiant energy onto a specific area of the heat absorber to improve the photothermal conversion efficiency; the surface of the heat absorber is coated with a high-temperature resistant selective absorption coating, and a spiral heat transfer working fluid flow channel is provided inside, which can maximize the absorption of the radiant energy reflected by the concentrating device and convert it into heat energy; the heat storage device consists of a molten salt storage tank and a double-loop heat exchanger, and is connected to the heat absorber and the generator set through a heat transfer working fluid loop, storing excess heat energy when the light is sufficient, and releasing heat energy to maintain the stable operation of the generator set when the concentrating intensity is insufficient; the generator set includes a steam turbine, a generator, and a condenser, and its function is to convert heat energy into electrical energy through the Rankine cycle and output it to the power grid.

[0026] The concentrating solar power generation system realizes the efficient conversion and stable output of photothermal energy through multi-dimensional cooperative design. The concentrating device is the energy capture center. The parabolic mirror converges the incident light to a linear or point focus area with its precise geometric surface, while the heliostat array dynamically calibrates the mirror angle through a high-precision two-axis tracking mechanism, so that the changes in the solar azimuth angle and altitude angle always meet the optical focusing requirements. Both technical paths can achieve a light intensity gain of hundreds to thousands of times. The heat absorber is the core of energy conversion. Its composite structure surface is composed of multiple layers of gradient materials. The surface titanium nitride-based spectral selective absorption film realizes the efficient capture of sunlight in a wide wavelength band through the interference effect, and the bottom antioxidant metal substrate forms a thermal resistance barrier. The double composite structure still maintains a photothermal conversion efficiency of over 90% under the working condition of 900 °C. The built-in double-spiral nested flow channel adopts a variable cross-section topology optimization design, strengthens turbulent heat transfer through the adjustment of the flow velocity gradient, and cooperates with the ultra-high thermal conductivity of the silicon carbide ceramic matrix composite material to achieve the uniform conduction of megawatt-level heat flux density.

[0027] The cooperative control module consists of a real-time data acquisition unit, a compensation strategy generation unit, and a control instruction unit. Among them, the real-time data acquisition unit respectively collects the light intensity fluctuation data of the concentrating device, the remaining heat storage capacity data of the heat storage device, and the frequency modulation demand data of the power grid through a light intensity sensor, a heat storage medium temperature sensor, and a power grid dispatching interface. The compensation strategy generation unit generates a dynamic compensation strategy based on the concentrating attenuation gradient calculation model, the thermodynamic property database of the heat storage medium, and the power grid frequency modulation demand prediction algorithm. The control instruction unit realizes the synchronous matching of the heat storage charging and discharging rate and the power generation power by adjusting the valve opening of the heat storage device, the rotation speed of the heat transfer working fluid pump, and the position of the steam turbine inlet valve.

[0028] The compensation strategy generation unit adopts a dynamic weight model to determine the priority of thermal energy storage compensation through the linear weighting of the concentrating attenuation gradient and the heat capacity of the thermal energy storage medium. For example, when the concentrating intensity rapidly decays due to cloud occlusion, the thermal energy storage unit with a high remaining thermal energy storage capacity is preferentially called for compensation. At the same time, in combination with the power ramp rate limit in the grid frequency modulation demand, the thermal energy storage compensation rate is dynamically adjusted to avoid overshoot of the power generation. The fuzzy control rule base divides the fluctuation level according to the duration of light intensity fluctuation and the gradient change rate. When the fluctuation level is level one, both the thermal energy storage compensation and the power generation smoothing algorithm are enabled. When the fluctuation level is level two, the amount of thermal energy storage compensation is restricted and the power regulation sensitivity of the generator set is increased. The two independent thermal energy storage units of the thermal energy storage device respectively adopt ceramic particles with high thermal conductivity and phase change materials with low thermal conductivity. When the concentrating intensity drops suddenly, the thermal energy of the thermal energy storage unit with high thermal conductivity is preferentially released to quickly respond to the power compensation demand. In the stage of light recovery, the thermal energy storage time is extended through the thermal energy storage unit with low thermal conductivity. The thermoelectric conversion efficiency feedback unit of the generator set monitors the mapping relationship between the temperature of the working medium at the inlet of the steam turbine and the power generation in real time, and feeds back the deviation signal to the control instruction unit to optimize the power setting value. The thermal energy storage medium temperature monitoring unit detects the temperature distribution through axially arranged multi-point thermocouples, and dynamically adjusts the charging and discharging rate in combination with the finite element model of thermal stress to ensure the operation safety of the thermal energy storage device. The communication unit of the cooperative control module adopts a 5G or optical fiber transmission protocol to ensure that the transmission delay of the light intensity fluctuation data, the remaining thermal energy storage capacity data and the frequency modulation demand data is less than 50 ms, and interacts with the grid dispatching system in real time to optimize the economic weight coefficient of the dynamic compensation strategy.

[0029] The working principle of a solar thermal power generation system provided by the present invention is as follows: The concentrating device captures solar radiant energy and reflects it to the heat absorber. After the heat transfer working medium absorbs the thermal energy, it is divided into two paths. One path is directly transported to the generator set to drive the steam turbine to generate electricity, and the other path enters the thermal energy storage device to store the thermal energy. When the light intensity sensor detects a decrease in the concentrating intensity, the cooperative control module generates a dynamic compensation strategy based on real-time data, synchronously adjusts the rate of releasing thermal energy by the thermal energy storage device and the output power of the generator set, so that the power generation matches the grid demand. In the stage of light recovery, the cooperative control module switches the thermal energy storage device to the heat charging mode and stores the excess thermal energy in the thermal energy storage unit with low thermal conductivity. During the whole process, the dynamic weight model and the fuzzy control rule base cooperate to optimize the priority of thermal energy storage compensation, and the thermoelectric conversion efficiency feedback and the thermal energy storage medium temperature monitoring unit form a closed-loop control to ensure the efficient and stable operation of the system under complex lighting conditions.

[0030] In summary, through the real-time integration and dynamic decision-making of the concentrator fluctuation, heat storage status, and grid demand by the collaborative control module, the present invention solves the problems of power fluctuation and waste of heat storage resources caused by the easy mismatch of the photothermal-electricity conversion chain in the traditional solar thermal power generation system. In the scenario of sudden change in the concentrator intensity, through the precise synchronous control of the heat storage compensation rate and the power generation power, the system response speed and operation stability are significantly improved. At the same time, combined with the optimization of the thermal stress distribution of the heat storage medium and the grid economic scheduling requirements, the equipment loss and operation and maintenance costs are reduced, realizing the efficient and reliable operation of the solar thermal power generation system in a complex environment.

[0031] The above-described embodiments of the present invention do not constitute a limitation on the protection scope of the present invention.

Claims

1. A solar thermal power generation system, characterized in that: It includes: a concentrator, a heat absorber, a heat storage device, a generator set and a coordinated control module; the concentrator is used to capture solar radiation energy and reflect it to the heat absorber; the heat absorber converts the received radiation energy into heat energy and transfers it to the heat transfer medium; the heat storage device is connected to the heat absorber and the generator set through a heat transfer medium loop, and is used to store or release heat energy; The generator set converts thermal energy into electrical energy and outputs it to the power grid; The collaborative control module includes: A real-time data acquisition unit, used to collect light intensity fluctuation data of the focusing device, remaining heat storage capacity data of the heat storage device and frequency modulation demand data of the power grid; A compensation strategy generating unit, which calculates the light concentration attenuation gradient based on the light intensity fluctuation data, and generates a dynamic compensation strategy in combination with the remaining heat storage capacity data and the frequency modulation demand data; The control instruction unit synchronously adjusts the charging and discharging rate of the heat storage device and the output power of the generator set according to the dynamic compensation strategy to achieve dynamic matching of light-heat conversion and electric energy output.

2. A solar thermal power generation system according to claim 1, characterized in that: The compensation strategy generation unit integrates the concentration attenuation gradient, the remaining heat storage capacity and the frequency regulation demand through a dynamic weight model, wherein: the dynamic weight model adjusts the heat storage compensation priority according to the real-time concentration attenuation gradient, and when the concentration attenuation gradient exceeds a preset threshold, the compensation amount is preferentially generated based on the remaining heat storage capacity; when the grid frequency regulation demand includes a power ramp rate constraint, the compensation rate of the heat storage device is dynamically reduced to match the power regulation margin of the generator set.

3. A solar thermal power generation system according to claim 1, characterized in that: The compensation strategy generation unit also includes a fuzzy control rule base, which is used to divide the triggering conditions of the compensation strategy according to the light intensity fluctuation level: When the light intensity fluctuation level is level one, the combined compensation mode of the heat storage device and the generator set is adopted; When the light intensity fluctuation level is level two, the compensation amount of the heat storage device is limited and the power smoothing algorithm of the generator set is started; the light intensity fluctuation level is comprehensively determined based on the time derivative and duration of the concentration attenuation gradient.

4. A solar thermal power generation system according to claim 1, characterized in that: The heat storage device includes at least two independent heat storage units, and the control instruction unit switches the heat charging and discharging modes of the heat storage units according to a dynamic compensation strategy: When the focusing intensity drops sharply due to cloud cover, the thermal energy of the high thermal conductivity heat storage unit is released first to quickly respond to the power compensation demand; when the focusing intensity is restored, the low thermal conductivity heat storage unit is switched to the charging mode to extend the heat storage time.

5. A solar thermal power generation system according to claim 1, characterized in that: The generator set includes a thermoelectric conversion efficiency feedback unit for real-time monitoring of the mapping relationship between the turbine inlet working fluid temperature and the generated power; the control instruction unit adjusts the output power setting value of the generator set according to the mapping relationship to minimize the deviation between the photothermal conversion efficiency and the grid frequency regulation requirement.

6. A solar thermal power generation system according to claim 1, characterized in that: The heat storage device also includes a heat storage medium temperature monitoring unit for obtaining the axial temperature distribution of the heat storage medium in real time; the control instruction unit dynamically adjusts the heat charging and discharging rate according to the axial temperature distribution so that the thermal stress of the heat storage medium does not exceed a preset safety threshold.

7. A solar thermal power generation system according to claim 1, characterized in that: The collaborative control module also includes a communication unit for transmitting the light intensity fluctuation data, remaining heat storage capacity data and frequency modulation demand data via 5G or optical fiber, and the data transmission delay is less than 50ms.

8. A solar thermal power generation system according to claim 1, characterized in that: The collaborative control module is in communication with the power grid dispatching system and is used to receive real-time electricity price signals and optimize the economic weight coefficient of the dynamic compensation strategy.

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