A method and system for light homogenization control of concentrated photovoltaic

Abstract

The application discloses a light-concentrating photovoltaic light-uniformity regulation method and system, belongs to the light-uniformity regulation technical field of light-concentrating photovoltaic, and aims to solve the problem that a light-concentrating photovoltaic module is easy to form a local high-illumination area and cause current mismatch, hot spots and power fluctuation under the conditions of solar elevation angle change, installation deviation and mirror deformation. The application synchronously acquires the solar position, the light spot image, the infrared thermal image and the component electrical parameter, reconstructs the actual irradiance matrix, and links the output posture correction amount and the output parameter adjustment amount, synchronously reacquires the solar elevation angle, the solar azimuth angle, the component installation deviation and the mirror surface deformation parameter in feedback, and realizes light-uniformity regulation and stable power generation.

Description

Technical Field

[0001] This invention relates to the field of concentrated photovoltaic uniform light control technology, and in particular to a concentrated photovoltaic uniform light control method and system. Background Technology

[0002] Concentrated photovoltaic systems enhance incident energy density through optical concentration, making them suitable for high-efficiency power generation. However, their light field is highly sensitive to the sun's position, the module's installation orientation, and the mirror's condition, which can easily lead to spot shifts and localized concentrations during actual operation.

[0003] Existing technologies often employ fixed optical paths, single tracking control, or simple electrical side adjustment, which makes it difficult to reflect changes in mirror deformation and light spot distribution in a timely manner, resulting in uneven light exposure of the solar cells, current mismatch, and localized temperature rise accumulation.

[0004] Under continuous high illuminance, hot spot risks will be further amplified, leading to packaging aging and output fluctuations. Existing solutions lack a closed-loop coordination between optical adjustment and electrical control, making it difficult to balance uniform light distribution and operational stability.

[0005] Therefore, there is a need for a method and system for controlling the uniform light distribution of concentrated photovoltaics that can overcome the shortcomings of the existing technologies. Summary of the Invention

[0006] The purpose of this invention is to propose a method and system for controlling the uniform light intensity of concentrated photovoltaic (CPV). This method involves simultaneously acquiring solar elevation angle, solar azimuth angle, module installation deviation, reflector deformation parameters, light spot calibration image, infrared thermal image, and module string current and voltage. It then reconstructs the actual irradiance matrix of the cell surface using initial ray tracing and residual self-correction. Based on light spot centroid deviation, non-uniformity factor, local peak irradiance, hot spot risk value, and current mismatch index, it performs hierarchical constraint model predictive control. At the optical layer, it coordinates the correction of the concentrator attitude and reflected light spot position; at the electrical layer, it synchronously adjusts the power peak tracking reference value, bypass switch control command, and DC-DC converter duty cycle; and at feedback, it synchronously re-acquires solar elevation angle, solar azimuth angle, module installation deviation, and reflector deformation parameters, thereby achieving light spot uniformity, hot spot suppression, and stable output control.

[0007] This invention provides a method for uniform light control in concentrated photovoltaic systems, comprising: S1, acquiring solar elevation angle, solar azimuth angle, module installation deviation, reflector deformation parameters, spot calibration image, infrared thermal image, and module series current and voltage; S2, establishing an initial ray tracing model based on solar elevation angle, solar azimuth angle, module installation deviation, reflector deformation parameters, and nominal optical path, and performing residual self-correction on the initial ray tracing model by combining the spot calibration image and infrared thermal image to reconstruct the actual irradiance matrix of the solar cells; S3, extracting spot centroid deviation, non-uniformity factor, local peak irradiance, hot spot risk value, and current mismatch index based on the actual irradiance matrix; S4, based on the spot centroid deviation, non-uniformity factor, and current mismatch index... The system calculates the condenser attitude correction and reflected spot offset, and then calculates the component output parameter adjustment. In step S5, the system adjusts the condenser attitude and mirror position based on the condenser attitude correction and reflected spot offset, and adjusts the power peak tracking reference value, bypass switch control command, or DC-DC converter duty cycle based on the component output parameter adjustment. When the hot spot risk value exceeds the hot spot risk threshold or the non-uniformity factor exceeds the non-uniformity threshold, the updated spot calibration image, infrared thermal image, component string current, and string voltage are used as feedback inputs, and the system returns to steps S1 to S5 to re-execute uniform light control.

[0008] Optionally, S1 includes:

[0009] The solar elevation angle and solar azimuth angle are obtained by a solar position sensor, the component installation deviation is obtained by an attitude sensor, the reflective mirror deformation parameters are obtained by a mirror deformation sensor or image measurement results, the light spot calibration image is obtained by a light spot imaging device, the infrared thermal image is obtained by an infrared thermal imager, and the component series current and series voltage are obtained by an electrical parameter sampling circuit. All the data are then unified to the same time scale.

[0010] Optionally, S2 includes:

[0011] An initial ray tracing model is established based on the solar altitude angle, solar azimuth angle, component installation deviation, reflector deformation parameters, and nominal optical path, and the nominal irradiance matrix is ​​output.

[0012] The light spot calibration image and infrared thermal image are converted into a light spot distribution map and a temperature rise distribution map, respectively, and then pixel-registered with the nominal irradiance matrix to generate a residual correction matrix.

[0013] The actual irradiance matrix is ​​reconstructed based on the nominal irradiance matrix and the residual correction matrix, and the actual irradiance matrix is ​​used for subsequent feature calculations.

[0014] Furthermore, the residual correction matrix is ​​jointly generated by the current calibration sample obtained by registering the spot calibration image and infrared thermal image with the nominal irradiance matrix in the current control cycle, the historical deviation samples in the pre-stored historical deviation sample library, and the thermal image error generated by the pixel difference between the infrared thermal image and the nominal irradiance matrix. Samples with sampling times closer to the current control cycle are given higher time decay weights, and the residual self-correction parameters are updated in a sliding window manner. The updated residual self-correction parameters are used to correct the actual irradiance matrix in the next control cycle.

[0015] Optionally, S3 includes:

[0016] The actual irradiance matrix is ​​partitioned according to the cell boundaries. The irradiance centroid of each partition is calculated and compared with the corresponding cell geometric center to obtain the spot centroid deviation.

[0017] Calculate the difference and ratio between the peak irradiance and the average irradiance of each zone to obtain the non-uniformity factor, and take the peak irradiance of each zone as the local peak irradiance.

[0018] The hot spot risk value is obtained by weighting the local peak illuminance, the temperature rise gradient at adjacent moments corresponding to the continuously acquired infrared thermal images, and the duration.

[0019] The current mismatch index is obtained by weighting the variance of the series current and the difference of the peak current of adjacent series. The spot centroid deviation, non-uniformity factor, local peak illuminance, hot spot risk value and current mismatch index are then used for subsequent linkage optimization.

[0020] Optionally, S4 includes:

[0021] In the rolling time domain, the optical layer targets are first set, including the centroid deviation of the light spot, the non-uniformity factor, and the local peak illuminance, and then the concentrator attitude correction and the reflected light spot offset are solved.

[0022] Then, using the hot spot risk value and current mismatch index as electrical layer constraints, and combining the attitude correction amount and reflected spot offset amount, the component output parameter adjustment amount is solved;

[0023] The component output parameter adjustment amount is output in a priority combination according to the bypass switch control command, the power peak tracking reference value, and the DC converter duty cycle, and the concentrator attitude correction amount, the reflected light spot offset amount, and the component output parameter adjustment amount are used for subsequent execution feedback.

[0024] Furthermore, a mirror deformation influence matrix is ​​established for the mirror deformation parameters. The mirror deformation influence matrix is ​​calibrated by the correspondence between the local curvature change and the spot centroid deviation and non-uniformity factor, and is used as a constraint prior for the concentrator attitude correction in step S4 to limit the single-cycle variation amplitude of the concentrator attitude correction.

[0025] Optionally, S5 includes:

[0026] The actuator is driven to adjust the condenser attitude and the reflector position according to the condenser attitude correction amount and the reflected light spot offset amount, and the power peak tracking reference value, bypass switch control command or DC converter duty cycle is adjusted according to the component output parameter adjustment amount.

[0027] Wherein, the hot spot risk threshold is determined by the quantile value of historical hot spot risk samples, and the non-uniformity threshold is determined by the quantile value of historical non-uniformity factor samples;

[0028] When the hot spot risk value exceeds the hot spot risk threshold or the non-uniformity factor exceeds the non-uniformity threshold, the lock state is set to valid and the current output parameters are frozen. The updated spot calibration image, infrared thermal image, component string current and string voltage, as well as the solar elevation angle, solar azimuth angle, component installation deviation and reflector deformation parameters re-acquired in the next control cycle are sent back to the aforementioned data acquisition process and irradiance reconstruction process so as to re-execute uniform light control in the next control cycle.

[0029] Furthermore, the electrical layer constraints further include an upper limit on component temperature rise and an upper limit on output change rate;

[0030] When the hot spot risk value exceeds the hot spot risk threshold or the non-uniformity factor exceeds the non-uniformity threshold, the locked state takes precedence over the rolling update state, locking the rolling update of the bypass switch control command, the power peak tracking reference value, and the DC converter duty cycle, and clearing the recovery count to zero.

[0031] During the period when the locked state is valid, the recovery count is incremented by 1 each time a control cycle is completed and the hot spot risk value and non-uniformity factor do not exceed the corresponding threshold; otherwise, the recovery count is cleared and the locked state is maintained.

[0032] When the recovery count reaches 3, the lockout is released and the bypass switch control command, power peak tracking reference value and DC converter duty cycle rolling update are restored synchronously.

[0033] When the hot spot risk value exceeds the hot spot risk threshold again or the non-uniformity factor exceeds the non-uniformity threshold again after the lock is released, the lock is reactivated, the recovery count is cleared, and the updated spot calibration image, infrared thermal image, component string current and string voltage, as well as the solar elevation angle, solar azimuth angle, component installation deviation and reflector deformation parameters re-acquired in the next control cycle are sent back to the aforementioned data acquisition process and irradiance reconstruction process to re-execute uniform light control.

[0034] On the other hand, the present invention also provides a concentrated photovoltaic uniform light control system, comprising:

[0035] The data acquisition module is used to acquire solar altitude angle, solar azimuth angle, component installation deviation, reflector deformation parameters, spot calibration image, infrared thermal image, and component series current and voltage. The irradiance reconstruction module is used to establish an initial ray tracing model based on the solar altitude angle, solar azimuth angle, component installation deviation, reflector deformation parameters, and nominal optical path, and to perform residual self-correction on the initial ray tracing model using the spot calibration image and infrared thermal image to reconstruct the actual irradiance matrix of the cell surface. The feature calculation module is used to extract spot centroid deviation, non-uniformity factor, local peak irradiance, hot spot risk value, and current mismatch index based on the actual irradiance matrix. The linkage optimization module is used to optimize the model based on the spot centroid deviation, non-uniformity factor, local peak irradiance, hot spot risk value, and current mismatch index. The index performs hierarchical constraint model predictive control in the rolling time domain, first solving for the concentrator attitude correction and reflected spot offset, and then solving for the component output parameter adjustment. A feedback module is executed to adjust the concentrator attitude and mirror position based on the concentrator attitude correction and reflected spot offset, and to adjust the power peak tracking reference value, bypass switch control command, or DC-DC converter duty cycle based on the component output parameter adjustment. When the hot spot risk value exceeds the hot spot risk threshold or the non-uniformity factor exceeds the non-uniformity threshold, the updated spot calibration image, infrared thermal image, component series current and voltage, and the solar elevation angle, solar azimuth angle, component installation deviation, and mirror surface deformation parameters re-acquired in the next control cycle are sent back to the data acquisition module and irradiance reconstruction module.

[0036] The beneficial effects of this invention are:

[0037] 1. This invention can uniformly map the sun's position, installation deviation, and mirror deformation to the actual irradiance matrix, reducing the deviation between the ideal model and the real light field.

[0038] 2. By linking the optical and electrical layers in a layered manner, local high illuminance, current mismatch and power fluctuations can be suppressed simultaneously, thereby improving the operational stability of concentrated photovoltaic modules.

[0039] 3. By using residual self-correction and threshold-triggered re-optimization, the system's adaptability to long-term drift and changes in operating conditions can be enhanced, and the aging risk caused by hot spot accumulation can be reduced. Attached Figure Description

[0040] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0041] Figure 1 This is a flowchart of a method for controlling the uniform light intensity of concentrated photovoltaic (CPV).

[0042] Figure 2 This is a flowchart of step S2 of the present invention, which reconstructs the actual irradiance matrix of the battery cell based on residual self-correction. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0044] refer to Figures 1-2 A method for uniform light control in concentrated photovoltaic (CPV) systems includes: S1, acquiring solar elevation angle, solar azimuth angle, module installation deviation, reflector deformation parameters, spot calibration image, infrared thermal image, and module series current and voltage; S2, establishing an initial ray tracing model based on the solar elevation angle, solar azimuth angle, module installation deviation, reflector deformation parameters, and nominal optical path, and performing residual self-correction on the initial ray tracing model using the spot calibration image and infrared thermal image to reconstruct the actual irradiance matrix of the solar cells; S3, extracting spot centroid deviation, non-uniformity factor, local peak irradiance, hot spot risk value, and current mismatch index based on the actual irradiance matrix; S4, based on the spot centroid deviation, non-uniformity factor, and... Local peak illuminance, hot spot risk value, and current mismatch index are used to perform hierarchical constraint model predictive control in the rolling time domain. First, the concentrator attitude correction and reflected spot offset are solved, and then the component output parameter adjustment is solved. S5: The concentrator attitude and mirror position are adjusted according to the concentrator attitude correction and reflected spot offset, and the power peak tracking reference value, bypass switch control command, or DC converter duty cycle is adjusted according to the component output parameter adjustment. When the hot spot risk value exceeds the hot spot risk threshold or the non-uniformity factor exceeds the non-uniformity threshold, the updated spot calibration image, infrared thermal image, component series current, and series voltage are used as feedback inputs, and the process returns to steps S1 to S5 to re-execute uniform light control.

[0045] In this specific embodiment, S1 includes:

[0046] The controller uses a fixed control cycle Run and generate a unified time-scaled sequence ,in Indicates the control period. Indicates the first The timescale of each control cycle Indicates the control cycle number;

[0047] Solar altitude angle With solar azimuth The solar position sensor, installed near the optical axis of the concentrator, outputs its position. During factory calibration, this sensor establishes an angular mapping between its coordinate system and the local horizontal coordinate system and fixes its calibration parameters. The controller then... Trigger a sampling and read and and its sampling timestamp;

[0048] The component installation deviation is measured by an attitude sensor fixed on the component reference beam and expressed as a tuple of Euler angle deviations. ,in Indicates crossflow deviation. Indicates pitch deviation. The attitude sensor, after installation, determines the zero deviation through static zero-position calibration and writes the zero deviation parameter into the controller to ensure that the output is the deviation amount relative to the installation reference.

[0049] The deformation parameters of the reflective mirror are obtained by an array of mirror deformation sensors and organized into vectors. ,in This represents the vector of mirror deformation parameters. Indicates the first The local curvature change corresponding to each measuring point The number of deformation measurement points is indicated. The curvature change is obtained by linear mapping and temperature drift compensation of the original sensor value through pre-calibration. The mapping coefficient and compensation coefficient are determined and stored in the controller during factory calibration.

[0050] The spot calibration image is acquired by a fixedly mounted spot imaging device whose field of view covers the receiving surface and is denoted as . ,in Indicates at the sampling time The imaging device performs intrinsic parameter calibration during installation and uses the intrinsic parameters for subsequent mapping of pixels to the physical coordinates of the receiving surface. The controller... Exposure is initiated using hardware triggering, and the image and exposure timestamp are read to avoid drift caused by software scheduling.

[0051] Infrared thermal images are acquired by infrared thermal imagers and recorded as... ,in Indicates at the sampling time The infrared thermal imager, upon initial deployment, sets the emissivity parameters of the measured surface and performs an environmental reflection temperature calibration to ensure repeatable temperature readings. The controller also uses hardware triggering for each... Get and its timestamp;

[0052] The current and voltage of the component string are synchronously acquired by the electrical parameter sampling circuit and recorded as follows: and ,in Indicates the sampling time Component string current, Indicates the sampling time The component string voltage, the electrical parameter sampling circuit in each Multi-point sampling is completed within a fixed sampling window, and the average value within the window is output to suppress the influence of switching ripple on control decisions;

[0053] To unify the data from the different sources mentioned above to the same time scale The controller uses linear interpolation to align each type of timestamped measurement to... Its expression is:

[0054] ;

[0055] in Indicates alignment to time scale The estimated quantity, and These represent the same measurement quantity at adjacent sampling times. and The original readings, and Indicates satisfaction Adjacent timestamps, Represents any measurement that is aligned and taken from in this step. and One of them, the controller will align , and Encapsulate them into data frames of the same control cycle and write them to the buffer queue for direct use in step S2.

[0056] In this specific embodiment, S2 includes:

[0057] Controller at time scale Read data frames from the same control cycle and establish a discrete grid on the receiving surface that matches the cell arrangement to form a matrix calculation reference. The number of rows and columns of the discrete grid are denoted as follows: and This indicates the number of grid cells on the receiving surface in the horizontal direction. This indicates the number of grid cells in the vertical direction of the receiving surface, and each grid cell corresponds one-to-one with the physical coordinates of the receiving surface. The cells are written into the cell assignment table according to the cell boundaries for subsequent partitioning.

[0058] The controller is based on the solar altitude angle. Sun azimuth Component installation deviation Mirror deformation parameter vector and nominal optical path parameter set Establish an initial ray tracing model, in which Indicates the first Each mirror measuring point is at The amount of local curvature change, Indicates the number of measuring points on the mirror surface. Fixed parameters, including the condenser's nominal geometric parameters, specular reflectivity, receiving surface position and orientation, and optical element transmittance, are fixed and solidified into the controller through dimensional measurement and optical performance testing during the system installation and commissioning phase.

[0059] The initial ray tracing model is based on and Calculate the direction of solar incidence, and use Construct an attitude error rotation to correct the nominal optical axis direction, while simultaneously... The surface shape is mapped to a continuous mirror shape to reflect the influence of deformation on the reflection normal. This surface shape is generated by bicubic spline interpolation of the local curvature changes at mirror measurement points on the mirror parameter coordinates, and the normal vector of each reflection point is calculated accordingly. The controller controls each... Launch a fixed number A beam of equal power is used, and its impact point and incident energy at the receiving surface are calculated according to the law of reflection. The energy is then accumulated according to the impact point. The nominal irradiance matrix is ​​obtained by dividing the grid cells by the cell area. ,in This represents the nominal irradiance matrix output by the initial ray tracing model. This represents the number of light lines used in ray tracing and is taken as follows in this embodiment: To ensure statistical stability within a single period;

[0060] The controller calibrates the light spot image. Dark field subtraction and flat field correction are performed, and pixel grayscale is converted into a spot distribution map. This conversion uses the irradiance calibration coefficients completed during the installation and commissioning phase to map the grayscale to irradiance units, and the results are resampled to the receiver surface grid forming matrix. ,in Indicates and Light spot distribution map within the same grid;

[0061] The controller monitors infrared thermal images. A temperature rise distribution map is generated based on the temperature value output by the thermal imager, and then resampled onto the receiving surface to form a matrix. ,in Indicates and The temperature rise distribution map of the same grid, with the temperature rise reference temperature taken as the median temperature of the non-focusing coverage area of ​​the receiving surface in the infrared thermal image, and in each Recalculate to eliminate environmental drift;

[0062] To ensure and and Per-pixel comparability: The controller uses the pixel registration relationship determined during the installation and commissioning phase to map the coordinates of the two images to the grid coordinates of the receiving surface. The pixel registration relationship is calculated by placing a planar calibration target on the receiving surface and acquiring calibration images of the spot imaging device and the infrared thermal imager. The calculation results are written into the controller as two sets of fixed homography matrices and directly called during operation to complete per-pixel registration and bilinear interpolation resampling.

[0063] The controller is registered with the current control cycle. and Compared to The pixel difference generates the current calibration sample, and the mean matrix of historical deviation samples consistent with the current operating condition label is read from the pre-stored historical deviation sample library. Simultaneously, a matrix is ​​generated from the pixel difference. and The thermal image error matrix obtained from the pixel difference is used to characterize the potential local over-irradiation or heat dissipation anomaly corresponding to "temperature rise is inconsistent with nominal irradiance".

[0064] The controller maintains the most recent data using a sliding window method. The current calibration sample for each control cycle and closer to the time The samples are assigned higher weights, and the weight sequence is fixed. And corresponding from near to far The weighted window mean, the historical deviation sample mean, and the thermal image error matrix are combined to form a residual correction matrix to complete residual self-correction. This residual correction matrix is ​​denoted as... And its numerical dimensions are the same as Consistent and zero-truncation of negative pixels after synthesis to avoid physically meaningless negative irradiance;

[0065] Controller by Reconstruct the actual irradiance matrix of the solar cell surface, where Indicates in The reconstructed actual irradiance matrix, Represents the nominal irradiance matrix. This represents the residual correction matrix obtained from residual self-correction, which the controller will use. The current period's pixel attribution table is written into shared memory for direct use in step S3. The current calibration sample and thermal imaging error matrix are then added to the historical deviation sample library to update the residual self-correction parameters for the next control period.

[0066] In this specific embodiment, S3 includes:

[0067] Controller at time scale Read the actual irradiance matrix from shared memory And the temperature rise distribution map of the same grid. Simultaneously, read the temperature rise distribution map from the previous control cycle. ,in Indicates the first A unified timescale for each control cycle. Indicates in The reconstructed actual irradiance matrix, Indicates in The obtained temperature rise distribution map, Indicates in The obtained temperature rise distribution map;

[0068] The controller reads the cell attribution table written in step S2 and... Classified by cell boundary Each partition ,in Indicates the number of solar cells. Indicates the first The set of pixels corresponding to each battery cell, and the pixel attribution table is determined and fixed to the controller during the system installation and commissioning phase by the receiving surface geometry, the number of grid rows and columns, and the battery cell arrangement position to ensure that each pixel belongs to only one battery cell partition;

[0069] For each partition The controller uses pixel irradiance as a weight to perform a weighted average of the pixel physical coordinates to obtain the irradiance centroid coordinates, and then calculates the difference between these irradiance centroid coordinates and the geometric center coordinates of the solar cell to obtain the spot centroid deviation. ,in Indicates the first Each battery cell The centroid deviation of the light spot, the geometric center coordinates are calculated from the fixed position of the battery cell layout in the receiving surface coordinate system and are fixed along with the cell assignment table. The physical coordinates of the cell are determined by the receiving surface size and grid division and are consistent with the grid definition in step S2.

[0070] For each partition The controller calculates the average irradiance of the zone. With peak irradiance ,in Indicates partition Inside The arithmetic mean, Indicates partition Inside The maximum value, the controller will As the local peak illuminance and according to the formula Calculate the non-uniformity factor, where Indicates the first Each battery cell The non-uniformity factor, Indicates the first Peak irradiance of each cell zone, Indicates the first Average irradiance of each cell zone;

[0071] Hot spot risk values ​​are calculated and aggregated by zone, and the controller outputs them in each zone. Internal The average temperature rise of the zone is obtained by averaging. and control cycle Calculate the temperature rise gradient between adjacent time points ,in Indicates the first Each partition The average temperature rise, Indicates the first Each partition The temperature gradient;

[0072] The controller maintains a duration counter for each partition. If and only if Greater than the average irradiance of the entire region 1.5 times and Greater than season Otherwise ,in Indicates time scale Average irradiance of all zones The reference irradiance is obtained by calculating the arithmetic mean. Indicates the temperature rise gradient threshold. Indicates the first Each partition Duration count;

[0073] The controller will include the local peak illuminance item. Temperature gradient term Duration item The risk components of hot spots in each region are obtained by weighted summation. ,in This represents the normalized reference value for the temperature rise gradient. This represents the normalized reference period for duration, with the three weights respectively taking... 0.20 and fixed configuration in the controller, the controller will output the hot spot risk value of the entire zone as and take For all partition hotspot risk components The maximum value is used to ensure sensitivity to the most dangerous local areas, where Indicates in Hot spot risk value;

[0074] The current mismatch index is calculated by the multi-component series current output by the electrical parameter sampling circuit within the same control cycle. The controller is time-scaled. Read Circuit component series current And according to the component wiring sequence Defined as the sequence number of adjacent strings, where Indicates the first Series current of circuit components Indicates the number of component strings. The controller calculates the variance of the current in that group as the string current variance and then... The peak current of each path is extracted within the sliding window of each control cycle to form... ,in Indicates the peak current extraction window length. Indicates the first The controller calculates the peak current difference between adjacent strings within the window. The current mismatch index is obtained by weighting it with the series current variance by weights of 0.60 and 0.40. ,in Indicates in The current mismatch index;

[0075] The controller will generate a sequence of light spot centroid deviations. Non-uniform factor sequences Local peak illuminance sequence Hot spot risk value With current mismatch index It is encapsulated into a feature set and written to shared memory for use in the linkage optimization of step S4.

[0076] In this specific embodiment, S4 includes:

[0077] Controller at time scale Read the spot centroid deviation sequence from shared memory Non-uniform factor sequences Local peak illuminance sequence Hot spot risk value With current mismatch index And establish a rolling time domain length of Hierarchical constraint model predictive control, in which Indicates the first Each control cycle timescale Indicates the cell partition number. Represents the number of rolling time-domain prediction steps and is related to the control period. This corresponds to a 6-second prediction window;

[0078] The controller defines the optical layer control quantity as the condenser attitude correction quantity. With the offset of the reflected light spot ,in This indicates the increment of the azimuth axis attitude correction angle. This indicates the increment of the pitch axis attitude correction angle. and These represent the positions of the reflector in the receiving surface coordinate system. direction and Equivalent offset in direction;

[0079] To perform solvable predictions in the rolling time domain, the controller uses steps... The initial ray tracing model, calculated offline and then fixed during the installation and debugging phase, will form a sensitivity model. and The sensitivity model maps incremental predictions to the next step of features by... Apply fixed small perturbations and repeat ray tracing to generate The finite difference is obtained and the perturbation amplitude is taken in this embodiment. and The resulting linearized coefficient matrix is ​​then written into the controller for each Used directly for prediction calculations;

[0080] The controller is in the optical layer to reduce as well as A quadratic programming problem is constructed with the rolling time-domain weighted sum as the objective, and actuator amplitude and rate of change constraints are applied, where the basic single-cycle amplitude limit for the attitude correction angle is taken as... The amplitude limit of the reflected light spot offset is taken And only the first step solution obtained in the rolling time domain. and The output is sent to S5 for execution;

[0081] Based on the prior constraints on the reflective mirror deformation, the controller establishes the mirror deformation influence matrix during the installation and commissioning phase. And used to limit The single-cycle variation amplitude, the By collecting The samples are obtained by running a set of samples and performing least-squares calibration. The running samples contain the mirror deformation parameter vector of each set of samples. The maximum spot centroid deviation of the entire partition obtained by synchronous calculation and the maximum non-uniformity factor of the entire partition ,in Indicates the first The local curvature change at each mirror measuring point Indicates the number of mirror measurement points, which will be used during calibration. As output, As input, fit to obtain And it is embedded into the controller;

[0082] In each The controller is based on the current Calculate the optical perturbation index caused by deformation Based on this, the single-cycle limit of the attitude correction angle is updated. Its update relationship is ,in Indicates time scale Single-cycle amplitude limiting of attitude correction angle. This represents the basic single-cycle limit under the a priori constraint of no deformation, and in this embodiment, it is taken as... This represents the perturbation index vector generated by the mirror deformation influence matrix and the reflection mirror deformation parameter vector. This represents the matrix representing the effect of mirror deformation. Indicates time scale The deformation parameter vector of the reflecting mirror surface, The norm of a vector is the sum of the absolute values ​​of its elements. (This is used in the controller.) and Replace the base limiter to automatically tighten the attitude correction amplitude when the mirror deformation increases, thereby suppressing spot oscillation caused by overcorrection;

[0083] After completing the optical layer solution and obtaining and Then, the controller enters the electrical layer to solve for the component output parameter adjustment and the hot spot risk value. With current mismatch index As a hard constraint input, and at the same time and The improvement in irradiance distribution for the next control cycle is taken as a known external disturbance compensation term for the electrical layer, and the adjustment of the electrical layer output parameters is defined as the bypass switch control command. Peak power tracking reference value Duty cycle of DC-DC converter ,in Represents the on / off control quantity of the bypass switch and its value set is: This indicates the reference voltage for MPPT control. This represents the PWM duty cycle of the DC-DC converter, and its value range is... ;

[0084] The electrical layer outputs the component electrical parameters based on the sampling circuit in the rolling time domain. and And the data collected and solidified during the installation and commissioning phase. The lookup table model predicts the output trend and satisfies the following conditions: and Minimize output fluctuation and mismatch without increasing constraints, while also... Apply a single-period rate of change constraint And on Apply a single-period rate of change constraint To ensure the feasibility of electrical control;

[0085] The electrical layer outputs are prioritized and fixed as follows: first, the bypass switch control command; then, the power peak tracking reference value; and finally, the DC-DC converter duty cycle. The controller, during the solution process, first checks... Does the condition satisfy the constraint? Solve the problem and output the solution if it exists, otherwise set it to zero. And freeze and To achieve rapid suppression of hot spots and mismatches, the controller will ultimately... , and The instruction set is encapsulated into the execution instruction set of step S5 and written into the execution cache for use in the next step.

[0086] In this specific embodiment, S5 includes:

[0087] Controller at time scale Read the concentrator attitude correction from the execution cache. With the offset of the reflected light spot And read the bypass switch control command from the component output parameter adjustment amount. Peak power tracking reference value Duty cycle of DC-DC converter ,in Indicates the first Each control cycle timescale This indicates the increment of the azimuth axis attitude correction angle. This indicates the increment of the pitch axis attitude correction angle. and These represent the equivalent displacement of the reflector in the receiving surface coordinate system. direction and The offset in direction. Represents the on / off control quantity of the bypass switch and its value set is: This indicates the reference voltage for MPPT control. This represents the PWM duty cycle of the DC-DC converter, and its value range is... ;

[0088] The actuator uses azimuth and pitch servo motors to drive the condenser's attitude. Both axes are equipped with absolute encoders, and the encoder readings serve as position closed-loop feedback. The controller will... and The incremental position mode command channel converts the target angle increments of both axes and sends them to the servo drive in a single control cycle. The internal positioning is completed, and the maximum angular velocity is set on the driver side. With maximum angular acceleration To ensure stable mechanical movement;

[0089] The position of the reflector is achieved by a two-dimensional micro-displacement mechanism and driven by a lead screw by two stepper motors. and Directional displacement, the controller will and The displacement is converted into step pulses and sent to the stepper driver. The displacement conversion factor is determined and fixed during the installation and debugging phase by the lead screw lead and microstepping factor. The driver side is set with a maximum single-cycle displacement of 2.0mm and a maximum speed. To avoid excitation of the reflector structure;

[0090] During electrical side execution, the controller will The controller will send the signal to the bypass switch drive circuit and use a break-before-make interlock timing sequence to avoid bypass loop jitter. The data is sent to the MPPT controller and the operating point is updated within the MPPT controller using a voltage reference closed-loop method. The controller will... The data is sent to the DC-DC converter's PWM module and takes effect in the next switching cycle, and is controlled at the hardware level. Set upper and lower limit protection as To avoid loss of control due to duty cycle limits;

[0091] To implement the threshold-triggered re-optimization and the locking and recovery mechanism, the controller in each Calculate the maximum non-uniformity factor of the entire partition. ,in This represents the non-uniform factor sequence output in step S3. The maximum value in the range is obtained, and the hot spot risk value output in step S3 is read. ,in This represents the hot spot risk value obtained by taking the maximum value of the hot spot risk component of the most dangerous local zone;

[0092] Hot spot risk threshold With non-uniform threshold The controller maintenance length is determined by historical sample quantile values. A circular historical sample queue is used to write the latest data in each control cycle. and After the queue is full, the quantile threshold is calculated by sorting and taking positions, and updated every 60 control cycles to reduce computational load. The threshold is calculated using the following formula:

[0093] ,

[0094] ;

[0095] in Indicates the hot spot risk threshold. Indicates a non-uniform threshold. This means calculating the input sample set. Quantile operator for quantile values This represents the hot spot risk quantile. Indicates non-uniform quantile coefficients. Indicates the 1st time step forward relative to the current time. Each control cycle timescale Indicates the length of the historical sample queue;

[0096] Controller maintenance lockout state With recovery count ,in Indicates in Is it in a locked state and the set of values ​​is The control cycle count, which represents the number of consecutive control cycles that meet the recovery condition while the lock state is in a locked state and takes a non-negative integer value, is implemented such that the locked state takes precedence over the rolling update state. The time controller does not use the newly solved step S4 in the current cycle. and Instead, it is frozen to the state of the last executed and confirmed execution. , and Meanwhile, it is still being implemented and To continuously eliminate the root causes of uneven light spots;

[0097] When the judgment or At that time, the controller will Set to 1 and The current output parameters are cleared and frozen, and the bypass switch control command is kept at the executed value at the trigger time to avoid frequent switching. The "feedback trigger flag" is set to valid to start the re-optimization loop of the next control cycle.

[0098] During the period when the lockout is active, the controller performs a threshold determination once per control cycle, if and only if and season Otherwise and maintain ,when When the value reaches 3, the controller will unlock and... Set to 0 and recover in the same cycle and The rolling update output;

[0099] It reappears after the lock is unlocked. or At that time, the controller immediately restarted Set to 1 and Clear to zero, and simultaneously reset the feedback trigger flag;

[0100] To ensure the effective implementation of the electrical layer constraints, the controller also performs hardware-side verification of the component temperature rise limit and the output change rate limit, wherein the component temperature rise limit is based on the temperature rise distribution map. The maximum average temperature rise across all cell zones was used as a criterion, along with a fixed upper limit. In comparison, the upper limit of the output rate of change is... and This serves as a criterion and is subject to amplitude limiting and cropping before issuance. Furthermore, if the upper limit temperature rise criterion is not met, the temperature rise will be directly reduced. Set to 1 and freeze the electrical side output parameters to prioritize safety;

[0101] When the feedback trigger flag is valid, the controller will update the spot calibration image at the end of this cycle. Infrared thermal imaging Component series current With component string voltage Write to the feedback queue and in the next control cycle Forced re-collection of solar altitude angle Sun azimuth Component installation deviation With the deformation parameter vector of the reflecting mirror And send it back to steps S1 and S2 to... Enter the re-execution of the uniform light control closed loop.

[0102] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0103] This invention forms a continuous control link through light spot acquisition, irradiance reconstruction, feature extraction, linkage optimization, and execution feedback, enabling the concentrator attitude, reflected light spot position, and component output parameters to be coordinated and adjusted under the same control framework.

[0104] This invention introduces a self-correcting residual layer and a hierarchical constraint control structure, which enables the optical adjustment results to directly constrain the electrical output and re-acquire the solar position and mirror state parameters in the next control cycle, thereby more effectively achieving uniform light, cooling and stable power.

Claims

1. A method for controlling the uniform light distribution in concentrated photovoltaic systems, characterized in that, include: S1. Acquire solar elevation angle, solar azimuth angle, component installation deviation, reflector deformation parameters, spot calibration image, infrared thermal image, and component series current and series voltage; S2. An initial ray tracing model is established based on the solar elevation angle, solar azimuth angle, component installation deviation, reflector deformation parameters and nominal optical path. The residual self-correction of the initial ray tracing model is performed by combining the light spot calibration image and infrared thermal image to reconstruct the actual irradiance matrix of the solar cell. S3. Extract the spot centroid deviation, non-uniformity factor, local peak illuminance, hot spot risk value and current mismatch index based on the actual irradiance matrix; S4. Based on the centroid deviation of the light spot, the non-uniformity factor, the local peak illuminance, the hot spot risk value and the current mismatch index, hierarchical constraint model predictive control is performed in the rolling time domain. First, the concentrator attitude correction amount and the reflected light spot offset amount are solved, and then the component output parameter adjustment amount is solved. S5. Adjust the condenser attitude and mirror position according to the condenser attitude correction amount and the reflected light spot offset amount, and adjust the power peak tracking reference value, bypass switch control command or DC converter duty cycle according to the component output parameter adjustment amount. When the hot spot risk value exceeds the hot spot risk threshold or the non-uniformity factor exceeds the non-uniformity threshold, the updated spot calibration image, infrared thermal image, component string current and string voltage are used as feedback inputs, and the process returns to steps S1 to S5 to re-execute the uniform light control.

2. The method according to claim 1, characterized in that, S1 includes: The solar elevation angle and solar azimuth angle are obtained through a solar position sensor, the component installation deviation is obtained through an attitude sensor, the reflector deformation parameters are obtained through a mirror deformation sensor or image measurement results, the spot calibration image is obtained through a spot imaging device, the infrared thermal image is obtained through an infrared thermal imager, and the component series current and series voltage are obtained through an electrical parameter sampling circuit. The solar elevation angle, solar azimuth angle, component installation deviation, reflector deformation parameters, spot calibration image, infrared thermal image, and component series current and series voltage are unified to the same time scale.

3. The method according to claim 1, characterized in that, S2 include: An initial ray tracing model is established based on the solar altitude angle, solar azimuth angle, component installation deviation, reflector deformation parameters, and nominal optical path, and the nominal irradiance matrix is ​​output. The light spot calibration image and infrared thermal image are converted into a light spot distribution map and a temperature rise distribution map, respectively, and then pixel-registered with the nominal irradiance matrix to generate a residual correction matrix. The actual irradiance matrix is ​​reconstructed based on the nominal irradiance matrix and the residual correction matrix, and the actual irradiance matrix is ​​used for subsequent feature calculations.

4. The method according to claim 1, characterized in that, S3 includes: The actual irradiance matrix is ​​partitioned according to the cell boundaries. The irradiance centroid of each partition is calculated and compared with the corresponding cell geometric center to obtain the spot centroid deviation. Calculate the difference and ratio between the peak irradiance and the average irradiance of each zone to obtain the non-uniformity factor, and take the peak irradiance of each zone as the local peak irradiance. The hot spot risk value is obtained by weighting the local peak illuminance, the temperature rise gradient at adjacent moments corresponding to the continuously acquired infrared thermal images, and the duration. The current mismatch index is obtained by weighting the variance of the series current and the difference of the peak current of adjacent series. The spot centroid deviation, non-uniformity factor, local peak illuminance, hot spot risk value and current mismatch index are then used for subsequent linkage optimization.

5. The method according to claim 1, characterized in that, S4 include: In the rolling time domain, the optical layer targets are first set, including the centroid deviation of the light spot, the non-uniformity factor, and the local peak illuminance, and then the concentrator attitude correction and the reflected light spot offset are solved. Then, using the hot spot risk value and current mismatch index as electrical layer constraints, and combining the attitude correction amount and reflected spot offset amount, the component output parameter adjustment amount is solved; The component output parameter adjustment amount is output in a priority combination according to the bypass switch control command, the power peak tracking reference value, and the DC converter duty cycle, and the concentrator attitude correction amount, the reflected light spot offset amount, and the component output parameter adjustment amount are used for subsequent execution feedback.

6. The method according to claim 1, characterized in that, S5 include: The actuator is driven to adjust the condenser attitude and reflector position according to the condenser attitude correction amount and the reflected light spot offset amount, and the power peak tracking reference value, bypass switch control command or DC converter duty cycle is adjusted according to the component output parameter adjustment amount. Wherein, the hot spot risk threshold is determined by the quantile value of historical hot spot risk samples, and the non-uniformity threshold is determined by the quantile value of historical non-uniformity factor samples; When the hot spot risk value exceeds the hot spot risk threshold or the non-uniformity factor exceeds the non-uniformity threshold, the lock state is set to valid and the current output parameters are frozen. The updated spot calibration image, infrared thermal image, component string current and string voltage, as well as the solar elevation angle, solar azimuth angle, component installation deviation and reflector deformation parameters re-acquired in the next control cycle are sent back to the aforementioned data acquisition process and irradiance reconstruction process so that uniform light control can be re-executed in the next control cycle.

7. The method according to claim 3, characterized in that, The residual correction matrix is ​​jointly generated by the current calibration sample obtained by registering the spot calibration image and infrared thermal image with the nominal irradiance matrix in the current control cycle, the historical deviation samples in the pre-stored historical deviation sample library, and the thermal image error generated by the pixel difference between the infrared thermal image and the nominal irradiance matrix. Samples with sampling times closer to the current control cycle are given higher time decay weights. The residual self-correction parameters are updated in a sliding window manner. The updated residual self-correction parameters are used to correct the actual irradiance matrix in the next control cycle.

8. The method according to claim 4, characterized in that, A mirror deformation influence matrix is ​​established for the deformation parameters of the reflecting mirror. The mirror deformation influence matrix is ​​calibrated by the correspondence between the local curvature change and the centroid deviation of the light spot and the non-uniformity factor, and is used as a constraint prior for the concentration attitude correction in step S4 to limit the single-cycle variation of the concentration attitude correction.

9. The method according to claim 6, characterized in that, The hot spot risk value and current mismatch index are used as electrical layer constraints, which further include upper limits for component temperature rise and output change rate. When the hot spot risk value exceeds the hot spot risk threshold or the non-uniformity factor exceeds the non-uniformity threshold, the locked state takes precedence over the rolling update state, locking the rolling update of the bypass switch control command, the power peak tracking reference value, and the DC converter duty cycle, and clearing the recovery count to zero. During the period when the locked state is valid, the recovery count is incremented by 1 each time a control cycle is completed and the hot spot risk value and non-uniformity factor do not exceed the corresponding threshold; otherwise, the recovery count is cleared and the locked state is maintained. When the recovery count reaches 3, the lockout is released and the bypass switch control command, power peak tracking reference value and DC converter duty cycle rolling update are restored synchronously. When the hot spot risk value exceeds the hot spot risk threshold again or the non-uniformity factor exceeds the non-uniformity threshold again after the lock is released, the lock is reactivated, the recovery count is cleared, and the updated spot calibration image, infrared thermal image, component string current and string voltage, as well as the solar elevation angle, solar azimuth angle, component installation deviation and reflector deformation parameters re-acquired in the next control cycle are sent back to the aforementioned data acquisition process and irradiance reconstruction process to re-execute uniform light control.

10. A concentrated photovoltaic uniform light control system, used to perform the method according to any one of claims 1 to 9, characterized in that, include: The data acquisition module is used to acquire solar altitude angle, solar azimuth angle, component installation deviation, reflector deformation parameters, spot calibration image, infrared thermal image, and component series current and series voltage; The irradiance reconstruction module is used to establish an initial ray tracing model based on the solar altitude angle, solar azimuth angle, component installation deviation, reflector deformation parameters and nominal optical path, and to perform residual self-correction on the initial ray tracing model by combining the light spot calibration image and infrared thermal image, and to reconstruct the actual irradiance matrix on the surface of the solar cell. The feature calculation module is used to extract the spot centroid deviation, non-uniformity factor, local peak illuminance, hot spot risk value and current mismatch index based on the actual irradiance matrix. The linkage optimization module is used to perform hierarchical constraint model predictive control in the rolling time domain based on the spot centroid deviation, non-uniformity factor, local peak illuminance, hot spot risk value and current mismatch index. It first solves the concentrator attitude correction amount and the reflected spot offset amount, and then solves the component output parameter adjustment amount. The execution feedback module is used to adjust the concentrator attitude and reflector position according to the concentrator attitude correction amount and the reflected light spot offset amount, and to adjust the power peak tracking reference value, bypass switch control command or DC converter duty cycle according to the component output parameter adjustment amount. When the hot spot risk value exceeds the hot spot risk threshold or the non-uniformity factor exceeds the non-uniformity threshold, the updated light spot calibration image, infrared thermal image, component series current and series voltage, as well as the solar elevation angle, solar azimuth angle, component installation deviation and reflector surface deformation parameters re-acquired in the next control cycle are sent back to the data acquisition module and irradiance reconstruction module.

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