A maximum power point tracking method and device based on output characteristics of a photovoltaic array

Abstract

The application discloses a maximum power point tracking method and device based on photovoltaic array output characteristics, wherein the photovoltaic array comprises photovoltaic components; the application utilizes the feature that each local optimal point of the photovoltaic array output power characteristic curve is located near the integer multiple of the open circuit voltage of the photovoltaic component, that is, each local optimal point is uniformly distributed based on the open circuit voltage of the photovoltaic component, and only needs to search the output power characteristic curve with the open circuit voltage of the photovoltaic component as a search step, so that the global optimal point of the output power characteristic curve, that is, the first maximum power point, can be quickly located; compared with the traditional tracking method, the application does not need to scan the complete photovoltaic array output power characteristic curve, and greatly improves the optimization speed; meanwhile, the particle swarm algorithm is utilized for accurate search, so that the actual global optimal point of the output power characteristic curve, that is, the target maximum power point, is obtained, and the algorithm is prevented from falling into local optimization.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic array technology, and specifically to a maximum power point tracking method and apparatus based on the output characteristics of a photovoltaic array. Background Technology

[0002] Photovoltaic arrays, as the energy conversion unit of photovoltaic (PV) power generation systems, are a research hotspot in the field of PV power generation technology. The PV output of a PV array exhibits complex nonlinear characteristics and is affected by external environmental factors such as temperature and light intensity. When the surface illumination of the PV array is uniform, its PV output shows a single-peak characteristic, and the PV curve has a global maximum power point. When the surface illumination of the PV array is uneven, such as when the PV array is shaded by fallen leaves, clouds, or other objects, the PV output will exhibit a multi-peak characteristic, and the PV curve will have several local maximum power points. In practical applications, PV power generation systems need to use appropriate control methods to ensure that the PV array always outputs maximum power, thereby improving the efficiency of the PV power generation system. This control process is known as Maximum Power Point Tracking (MPPT).

[0003] Most existing maximum power point tracking (MPPT) methods utilize complex mathematical methods or combine them with deep learning, making them difficult to implement and implement in practice. Furthermore, most methods require scanning the entire power point characteristic curve, resulting in slow search speeds. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a maximum power point tracking method and apparatus based on the output characteristics of a photovoltaic array, in order to solve the technical problems of high difficulty in implementing maximum power point tracking, complex implementation process, difficulty in practical application, and slow search speed in the prior art.

[0005] The technical solution proposed in this invention is as follows:

[0006] In a first aspect, embodiments of the present invention provide a maximum power point tracking method based on the output characteristics of a photovoltaic array, wherein the photovoltaic array includes photovoltaic modules; the maximum power point tracking method based on the output characteristics of the photovoltaic array includes: acquiring the output voltage, output current, and a first open-circuit voltage of the photovoltaic array and the photovoltaic modules; determining the volt-ampere characteristic curve and the output power characteristic curve of the photovoltaic array based on the output voltage and the output current; using the first open-circuit voltage as the search step size, and utilizing the distribution principle that the local optima of the volt-ampere characteristic curve and the output power characteristic curve are uniformly distributed with the first open-circuit voltage as the base quantity, searching in the output power characteristic curve to obtain a first maximum power point; and obtaining the target maximum power point of the photovoltaic array by processing the first maximum power point using a particle swarm optimization algorithm.

[0007] In conjunction with the first aspect, in one possible implementation of the first aspect, obtaining the first open-circuit voltage of the photovoltaic module includes: obtaining the second open-circuit voltage of the photovoltaic array and the number of series-connected cells in the photovoltaic array; and determining the first open-circuit voltage based on the second open-circuit voltage and the number of series-connected cells.

[0008] In conjunction with the first aspect, in another possible implementation of the first aspect, using the first open-circuit voltage as the search step size, and utilizing the distribution principle that the local optima of the current-voltage characteristic curve and the output power characteristic curve are uniformly distributed with the first open-circuit voltage as the base quantity, a search is performed in the output power characteristic curve to obtain the first maximum power point. This includes: determining an initial point voltage based on the first open-circuit voltage; determining a maximum search voltage based on the initial point voltage, the first open-circuit voltage, and the number of series-connected batteries; determining a search range based on the initial point voltage and the maximum search voltage; and within the search range, searching in the output power characteristic curve based on the current-voltage characteristic curve, using the first open-circuit voltage as the search step size, to obtain the first maximum power point.

[0009] In conjunction with the first aspect, in another possible implementation of the first aspect, within the search range, based on the current-voltage characteristic curve, a search is performed on the output power characteristic curve with the first open-circuit voltage as the search step size to obtain the first maximum power point, comprising: obtaining a first voltage of the photovoltaic array; determining a first current of the photovoltaic array in the current-voltage characteristic curve based on the first voltage; determining a first power of the photovoltaic array based on the first voltage and the first current; updating the first voltage based on the search step size, and obtaining the updated second voltage and second current of the photovoltaic array; determining a second power of the photovoltaic array based on the second voltage and the second current; comparing the second power and the first power; when the second power is greater than the first power, updating the first power using the second power and updating the first voltage using the second voltage, until the second voltage iterates to the maximum search voltage and the iteration stops to obtain a target voltage; and determining the first maximum power point in the output power characteristic curve based on the target voltage.

[0010] In conjunction with the first aspect, in another possible implementation of the first aspect, after comparing the second power and the first power, the method further includes: when the second power is less than the first power, determining the first maximum power of the photovoltaic array based on the current-voltage characteristic curve, the maximum search voltage, and the second current; comparing the first maximum power with the first power; when the first maximum power is greater than the first power, repeating the steps of updating the first voltage based on the search step size and obtaining the updated second voltage and second current of the photovoltaic array to the step of determining the first maximum power point in the output power characteristic curve based on the target voltage; when the first maximum power is less than and equal to the first power, determining whether the second power is equal to the first power; when the second power is equal to the first power, taking the power point corresponding to the second power as the first maximum power point.

[0011] In conjunction with the first aspect, in another possible implementation of the first aspect, the target maximum power point of the photovoltaic array is obtained based on the first maximum power point through particle swarm optimization (PSO) processing, including: determining a third voltage of the photovoltaic array in the output power characteristic curve based on the first maximum power point; determining an initial voltage for each particle based on the third voltage; calculating a first search power for each particle based on the initial voltage of each particle; determining a second maximum power and a third maximum power of the photovoltaic array based on each first search power; updating the position and velocity of each particle, and determining whether the second maximum power is equal to the third maximum power; when the second maximum power is equal to the third maximum power, obtaining a fourth voltage and a third current of the photovoltaic array; determining a third power of the photovoltaic array based on the fourth voltage and the third current; determining whether the third power meets a preset power range; and when the third power meets the preset power range, taking the power point corresponding to the second maximum power as the target maximum power point.

[0012] In conjunction with the first aspect, in another possible implementation of the first aspect, after updating the position and velocity of each particle and determining whether the second maximum power is equal to the third maximum power, the method further includes: when the second maximum power is not equal to the third maximum power, repeating the step of calculating the first search power of each particle based on the initial voltage of each particle based on the updated particle until the third power satisfies the preset power range, and then taking the power point corresponding to the second maximum power as the target maximum power point.

[0013] Secondly, embodiments of the present invention provide a maximum power point tracking device based on the output characteristics of a photovoltaic array, wherein the photovoltaic array includes photovoltaic modules; the maximum power point tracking device based on the output characteristics of the photovoltaic array includes: an acquisition module, used to acquire the output voltage, output current and first open-circuit voltage of the photovoltaic array and the photovoltaic modules; a determination module, used to determine the volt-ampere characteristic curve and the output power characteristic curve of the photovoltaic array based on the output voltage and the output current; a search module, used to search in the output power characteristic curve with the first open-circuit voltage as the search step size and utilizing the distribution principle that the local optima of the volt-ampere characteristic curve and the output power characteristic curve are uniformly distributed with the first open-circuit voltage as the base quantity, to obtain a first maximum power point; and a processing module, used to obtain the target maximum power point of the photovoltaic array by processing the first maximum power point using a particle swarm optimization algorithm.

[0014] Thirdly, embodiments of the present invention provide a computer-readable storage medium storing a computer program for causing the computer to execute the maximum power point tracking method based on the output characteristics of a photovoltaic array as described in the first aspect and any one of the embodiments of the present invention.

[0015] Fourthly, embodiments of the present invention provide an electronic device, including: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores a computer program, and the processor executes the computer program to perform the maximum power point tracking method based on the output characteristics of a photovoltaic array as described in the first aspect and any one of the embodiments of the present invention.

[0016] The technical solution provided by this invention has the following effects:

[0017] The maximum power point tracking (MPPT) method based on the output characteristics of a photovoltaic (PV) array provided in this invention utilizes the characteristic that all local optima of the PV array's output power characteristic curve are located near integer multiples of the PV module's open-circuit voltage. That is, each local optima is uniformly distributed with the PV module's open-circuit voltage as a baseline. By searching the output power characteristic curve using the PV module's open-circuit voltage as the search step size, the global optimum of the output power characteristic curve, i.e., the first maximum power point, can be quickly located. Compared with traditional tracking methods, it eliminates the need to scan the entire PV array's output power characteristic curve, significantly improving the optimization speed. Simultaneously, it uses a particle swarm optimization algorithm for precise searching, obtaining the actual global optimum of the output power characteristic curve, i.e., the target maximum power point, avoiding the algorithm getting trapped in local optima. Furthermore, the search process utilizes the inherent characteristics of the PV array during operation, exhibiting universality and high reliability, and can be further applied to the promotion and use of PV power plants. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a flowchart of a maximum power point tracking method based on the output characteristics of a photovoltaic array according to an embodiment of the present invention;

[0020] Figure 2 This is a flowchart of step 103 provided according to an embodiment of the present invention;

[0021] Figure 3 This is a flowchart of step 104 provided according to an embodiment of the present invention;

[0022] Figure 4 This is another flowchart of a maximum power point tracking method based on the output characteristics of a photovoltaic array provided in an embodiment of the present invention;

[0023] Figure 5 This is an equivalent circuit diagram of a 4×2 photovoltaic array provided according to an embodiment of the present invention;

[0024] Figure 6 This is an output characteristic curve of a 4×2 photovoltaic array provided according to an embodiment of the present invention;

[0025] Figure 7 This is a structural block diagram of a maximum power point tracking method device based on the output characteristics of a photovoltaic array according to an embodiment of the present invention;

[0026] Figure 8 This is a schematic diagram of the structure of a computer-readable storage medium provided according to an embodiment of the present invention;

[0027] Figure 9 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] This invention provides a maximum power point tracking method based on the output characteristics of a photovoltaic array, such as... Figure 1 As shown, the method includes the following steps:

[0031] Step 101: Obtain the output voltage and output current of the photovoltaic array and the first open-circuit voltage of the photovoltaic module.

[0032] The photovoltaic array includes photovoltaic modules.

[0033] Specifically, the output voltage and output current of the photovoltaic array and the first open-circuit voltage V of the photovoltaic module are collected. OC,M .

[0034] Step 102: Based on the output voltage and the output current, determine the current-voltage characteristic curve and the output power characteristic curve of the photovoltaic array.

[0035] Specifically, based on the collected output voltage and output current of the photovoltaic array, the volt-ampere characteristic curve (IU characteristic curve) and the output power characteristic curve (PU characteristic curve) of the photovoltaic array can be obtained.

[0036] Step 103: Using the first open-circuit voltage as the search step size, and utilizing the distribution principle of the local optimum of the volt-ampere characteristic curve and the output power characteristic curve being uniformly distributed with the first open-circuit voltage as the base quantity, search in the output power characteristic curve to obtain the first maximum power point.

[0037] Specifically, using the IU characteristic curve, based on the local optimum of the photovoltaic array PU characteristic curve, the first open-circuit voltage V of the photovoltaic module is used. OC,M The principle of uniform distribution of basic quantity, with V OC,M The global optimum of the PU characteristic curve is searched with a search step size ΔV, which is the first maximum power point.

[0038] Step 104: Based on the first maximum power point, the target maximum power point of the photovoltaic array is obtained through particle swarm optimization.

[0039] In the particle swarm optimization algorithm described in this embodiment of the invention, there are N particles with dimension d, position vector S, and velocity vector V. The position matrix S of the d-dimensional particle swarm is then... d The following relation (1) is shown:

[0040] S d =(S 1d ,S 2d ,S 3d ,…,S Nd (1)

[0041] In the formula: S Nd This represents the position matrix of the Nth d-dimensional particle.

[0042] d-dimensional particle swarm velocity matrix V d The following relation (2) is shown:

[0043] V d =(V 1d V 2d V 3d ,…,V Nd (2)

[0044] In the formula: V Nd This represents the velocity matrix of the Nth d-dimensional particle.

[0045] The velocity vector iteration formula for the particle is shown in the following relation (3):

[0046]

[0047] In the formula: V id ω represents the velocity vector of the particle; c1 and c2 represent the weights of the individual particle's velocity in the previous iteration; r1 and r2 represent random numbers used to adjust the step size of the learning factors; j represents the iteration number; P best,id G represents the historical best value of the particle's position. best,id S represents the global optimal value of the particle's position. id The position vector of the particle is represented by the following relation (4):

[0048]

[0049] In this embodiment of the invention, N is the initial number of search points on the PU characteristic curve; P best,id G represents the local maximum power found at each search point. best,idThis represents the global maximum power found at each search point.

[0050] Specifically, the particle swarm optimization algorithm is used to accurately search for the actual maximum power point of the PU characteristic curve, i.e., the target maximum power point P, near the first maximum power point. GM .

[0051] By using the particle swarm optimization algorithm, the maximum power point being searched is avoided as a local optimum, thus improving the tracking accuracy of the maximum power point.

[0052] The maximum power point tracking (MPPT) method based on the output characteristics of a photovoltaic (PV) array provided in this invention utilizes the characteristic that all local optima of the PV array's output power characteristic curve are located near integer multiples of the PV module's open-circuit voltage. That is, each local optima is uniformly distributed with the PV module's open-circuit voltage as a baseline. By searching the output power characteristic curve using the PV module's open-circuit voltage as the search step size, the global optimum of the output power characteristic curve, i.e., the first maximum power point, can be quickly located. Compared with traditional tracking methods, it eliminates the need to scan the entire PV array's output power characteristic curve, significantly improving the optimization speed. Simultaneously, it uses a particle swarm optimization algorithm for precise searching, obtaining the actual global optimum of the output power characteristic curve, i.e., the target maximum power point, avoiding the algorithm getting trapped in local optima. Furthermore, the search process utilizes the inherent characteristics of the PV array during operation, exhibiting universality and high reliability, and can be further applied to the promotion and use of PV power plants.

[0053] As an optional implementation of the present invention, obtaining the first open-circuit voltage of the photovoltaic module includes: obtaining the second open-circuit voltage of the photovoltaic array and the number of series-connected cells in the photovoltaic array; and determining the first open-circuit voltage based on the second open-circuit voltage and the number of series-connected cells.

[0054] Specifically, the second open-circuit voltage V of the photovoltaic array is measured. OC,Array The number of cells N in series with the photovoltaic array S .

[0055] The first open-circuit voltage V of the photovoltaic array is calculated using the following relationship (5). OC,M :

[0056]

[0057] As an optional implementation of the present invention, such as Figure 2As shown, step 103 includes: determining an initial point voltage based on the first open-circuit voltage; determining a maximum search voltage based on the initial point voltage, the first open-circuit voltage, and the number of series-connected batteries; determining a search range within the search range based on the initial point voltage and the maximum search voltage; and searching the output power characteristic curve based on the volt-ampere characteristic curve with the first open-circuit voltage as the search step size to obtain the first maximum power point.

[0058] Specifically, a search step size of 0.5 times ΔV is used as the initial point voltage ΔV. 1st The following relation (6) is shown:

[0059]

[0060] Maximum search voltage V LIM That is, the last local optimum is located at (N) S -1)V CC,M and N S V OC,M The relationship between them is shown in the following equation (7):

[0061] V LIM =(N S -1)ΔV+ΔV 1st (7)

[0062] Furthermore, the search range is the initial point voltage ΔV. 1st and maximum search voltage V LIM between.

[0063] Furthermore, at the initial point voltage ΔV 1st and maximum search voltage V LIM Between these points, the search is performed on the PU characteristic curve with a search step size ΔV to obtain the first maximum power point.

[0064] Furthermore, such as Figure 2As shown, within the search range, based on the current-voltage characteristic curve, and with the first open-circuit voltage as the search step size, a search is performed on the output power characteristic curve to obtain the first maximum power point. This includes: obtaining a first voltage of the photovoltaic array; determining a first current of the photovoltaic array in the current-voltage characteristic curve based on the first voltage; determining a first power of the photovoltaic array based on the first voltage and the first current; updating the first voltage based on the search step size, and obtaining the updated second voltage and second current of the photovoltaic array; determining a second power of the photovoltaic array based on the second voltage and the second current; comparing the second power with the first power; when the second power is greater than the first power, updating the first power using the second power and updating the first voltage using the second voltage, until the second voltage iterates to the maximum search voltage and the iteration stops, obtaining a target voltage; and determining the first maximum power point in the output power characteristic curve based on the target voltage.

[0065] Specifically, the current voltage of the photovoltaic array is measured, i.e., the first voltage V. PV .

[0066] Then, based on the measured first voltage V PV The corresponding first current I can be determined from the IU characteristic curve. PV .

[0067] Furthermore, the current power of the photovoltaic array, i.e., the first power P, is calculated using the following relationship (8). PV :

[0068] P PV =V PV ×I PV (8)

[0069] Furthermore, the current power P of the storage photovoltaic array PV and current voltage V PV And denoted as P PV,stored and V PV,stored .

[0070] Furthermore, with a search step size ΔV = V OC,M Update the voltage of the photovoltaic array, i.e., the first voltage, and measure the second voltage and second current of the updated photovoltaic array.

[0071] Furthermore, by substituting the second voltage and the second current into the above relationship (8), the updated second power of the photovoltaic array is calculated.

[0072] Furthermore, the updated second power of the photovoltaic array and the original first power, i.e., the currently recorded power P of the photovoltaic array, are compared. PV,storedCompare them.

[0073] Furthermore, when the updated second power of the photovoltaic array is greater than the currently recorded power P of the photovoltaic array... PV,stored When the time comes, the currently recorded power P of the photovoltaic array is overwritten with the updated second power and second voltage. PV,stored And the voltage V of the currently recorded photovoltaic array PV,stored Until the second voltage of the photovoltaic array after the update iterates to the maximum search voltage V. LIM .

[0074] Finally, based on the second voltage of the photovoltaic array after the iteration stops, i.e. the target voltage, the global optimum, i.e. the first maximum power point, is determined in the PU characteristic curve.

[0075] As an optional implementation of the present invention, such as Figure 2 As shown, after comparing the second power and the first power, the method further includes: when the second power is less than the first power, determining the first maximum power of the photovoltaic array based on the current-voltage characteristic curve, the maximum search voltage, and the second current; comparing the first maximum power with the first power; when the first maximum power is greater than the first power, repeating the steps of updating the first voltage based on the search step size and obtaining the updated second voltage and second current of the photovoltaic array to the step of determining the first maximum power point in the output power characteristic curve based on the target voltage; when the first maximum power is less than and equal to the first power, determining whether the second power is equal to the first power; when the second power is equal to the first power, taking the power point corresponding to the second power as the first maximum power point.

[0076] Specifically, when the updated second power of the photovoltaic array is less than the currently recorded power P of the photovoltaic array. PV,stored When the maximum power P that may appear on the PU characteristic curve after the current point is calculated, then... LIM That is, the first maximum power.

[0077] Among them, the IU characteristic curve of the photovoltaic array increases with the increase of the photovoltaic array voltage, and reaches the next V... OC,M Previously, the current would remain constant or decrease. In this embodiment of the invention, it is assumed that the maximum search voltage V is reached. LIM Pre-I PV If the first maximum power P of the photovoltaic array remains unchanged, LIM The following relation (9) is shown:

[0078] P LIM =V LIM ×I PV (9)

[0079] Furthermore, the first maximum power P LIM And the power P of the currently recorded photovoltaic array PV,stored Compare them.

[0080] When the first maximum power P LIM The power P of the photovoltaic array is greater than the currently recorded value. PV,stored If the value of the maximum power point is found, it indicates that there is a larger power point in the PU characteristic curve. Then, the voltage of the photovoltaic array is updated with a search step size ΔV, and the search continues until the first maximum power point is obtained.

[0081] When the first maximum power P LIM Less than or equal to the power P of the currently recorded photovoltaic array PV,stored At that time, set the current voltage of the photovoltaic array to be equal to the currently recorded voltage V of the photovoltaic array. PV,stored It then determines whether the current power of the photovoltaic array, i.e., the second power, is equal to the currently recorded power P of the photovoltaic array. PV,stored That is, the first power.

[0082] Furthermore, if the second power is equal to the currently recorded power P of the photovoltaic array... PV,stored Then the second power is stored, and the power point corresponding to the second power is used as the first maximum power point.

[0083] Furthermore, if the second power is not equal to the currently recorded power P of the photovoltaic array... PV,stored If so, return to step 101 above.

[0084] As an optional implementation of the present invention, such as Figure 3 As shown, step 104 includes: determining a third voltage of the photovoltaic array in the output power characteristic curve based on the first maximum power point; determining an initial voltage for each particle based on the third voltage; calculating a first search power for each particle based on the initial voltage of each particle; determining a second maximum power and a third maximum power of the photovoltaic array based on each first search power; updating the position and velocity of each particle, and determining whether the second maximum power is equal to the third maximum power; when the second maximum power is equal to the third maximum power, acquiring a fourth voltage and a third current of the photovoltaic array; determining a third power of the photovoltaic array based on the fourth voltage and the third current; determining whether the third power meets a preset power range; when the third power meets the preset power range, taking the power point corresponding to the second maximum power as the target maximum power point.

[0085] Specifically, using the first maximum power point, the third voltage of the photovoltaic array is determined in the PU characteristic curve, which is the V that is finally stored and recorded. PV,stored.

[0086] Furthermore, in this embodiment of the invention, the V is between 0.85 and 1.15 times. PV,stored Initialize the voltage at 5 search points within the interval.

[0087] Specifically, the initial current at each search point is determined in the IU characteristic curve based on the initial voltage at each search point.

[0088] Furthermore, based on the initial voltage and initial current of each search point, and using the above relationship (8) and the output power characteristic curve, the first search power of each search point can be calculated.

[0089] Furthermore, by comparing each first search power, the local maximum power, i.e., the second maximum power G, is obtained. best,id That is, the second maximum power and the global maximum power, which is the third maximum power P. best,id

[0090] Furthermore, the position and velocity of each particle are updated, and the second maximum power G is determined. best,id Is it equal to the third maximum power P? best,id .

[0091] When the second maximum power G best,id Equal to the third maximum power P best,id At that time, the fourth voltage and the third current of the photovoltaic array are measured, and the third power of the photovoltaic array can be calculated using the above relationship (8) based on the measured fourth voltage and the third current.

[0092] The preset power range is determined based on the third maximum power, ranging from 98% of the third maximum power to 102% of the third maximum power.

[0093] Furthermore, when the third power is within the aforementioned preset power range, it indicates that the operating condition of the photovoltaic array has not changed. That is, the second maximum power is the maximum power output of the photovoltaic array at this time. Furthermore, the power point corresponding to the second maximum power is the target maximum power point.

[0094] Furthermore, when the third power is not within the preset power range, it indicates that the operating condition of the photovoltaic array has changed, and it is necessary to start searching for the maximum power point of the photovoltaic array from scratch, i.e., return to step 101.

[0095] As an optional implementation of the present invention, such as Figure 3As shown, after updating the position and velocity of each particle and determining whether the second maximum power is equal to the third maximum power, the method further includes: when the second maximum power is not equal to the third maximum power, repeating the step of calculating the first search power of each particle based on the initial voltage of each particle based on the updated particle until the third power satisfies the preset power range, and then taking the power point corresponding to the second maximum power as the target maximum power point.

[0096] Specifically, the second maximum power G best,id Not equal to the third maximum power P best,id At that time, a precise search is performed again based on each updated particle, that is, the step of "calculating the first search power of each particle based on the initial voltage of each particle" is returned, and the step of "when the third power meets the preset power range, the power point corresponding to the second maximum power is taken as the target maximum power point" is repeated.

[0097] In one example, a maximum power point tracking method based on the output characteristics of a photovoltaic array is provided, the flowchart of which is as follows. Figure 4 As shown, it includes the following steps:

[0098] Step 1: Setting initial conditions, taking a 4×2 photovoltaic array as an example, N s V is 4. OC,M The voltage is 43.6V, and the equivalent circuit diagram of the photovoltaic array used is as follows: Figure 5 As shown, the output characteristic curve of the photovoltaic array is as follows: Figure 6 As shown.

[0099] 1. Set the step size ΔV:

[0100]

[0101] Among them, V OC,Array This is the open-circuit voltage of the photovoltaic array.

[0102] 2. Set the initial point ΔV 1st :

[0103]

[0104] 3. Set the maximum search voltage V LIM :

[0105] V LIM =(N S -1)ΔV+ΔV 1st

[0106] The purpose of this step is to provide initial values ​​and search range for step two.

[0107] Step 2: Search for the global optimum (maximum power point on the PU characteristic curve)

[0108] 1. Set the initial voltage V of the photovoltaic array PV :

[0109] V PV =ΔV 1st

[0110] 2. Measure the voltage V of the photovoltaic array. PV Current I PV Calculate the photovoltaic array power P PV :

[0111] P PV =V PV ×I PV

[0112] 3. Power storage of photovoltaic array P PV Photovoltaic array voltage V PV .

[0113] 4. Update the photovoltaic array voltage V PV =ΔV PV,stored +ΔV.

[0114] 5. Measure V after the voltage update. PV I PV Calculate P PV .

[0115] 6. Determine P PV Is it greater than P? PV,stored .

[0116] 7. If P PV Greater than P PV,stored Then overwrite P PV,stored and V PV,stored After overwriting, determine V. PV Is it equal to V? LIM If it is not equal, return to step 4; if it is equal, go to step 3.

[0117] 8. If P PV Less than or equal to P PV,stored Then calculate P LIM =V LIM ×I PV .

[0118] 9. Determine P LIM Is it greater than P? PV,stored .

[0119] 10. If P LIM Greater than P PV,stored Then return to step 4.

[0120] 11. If P LIM Less than or equal to P PV,stored Then set V PV equals V PV,stored .

[0121] 12. Determine P PV Is it equal to P? PV,stored If P PV equals P PV,stored Then proceed to step three; if P PV Not equal to P PV,stored If so, return to step one.

[0122] Step 3: Use the particle swarm optimization algorithm to search for the actual maximum power point.

[0123] 1. Following step two, utilize the V stored at the end of step two. PV,stored (i.e., the global optimum obtained in step two), within a range of 0.85 to 1.15 times V PV,stored Initialize the voltage for 5 particles within the interval;

[0124] 2. Calculate the power of each particle point;

[0125] 3. Compare the power to obtain the global maximum power and the historical maximum power (local maximum power);

[0126] 4. Update the position and velocity of the particles;

[0127] 5. Determine whether the maximum power point has been reached;

[0128] 6. If the maximum power point is not reached, proceed to step 2; otherwise, proceed to step 7.

[0129] 7. Store the maximum power point P GM ;

[0130] 8. Measure V PV I PV Calculate P PV ;

[0131] 9. Determine P PV Is it at 98% P GM Up to 102% P GM between;

[0132] 10. If the determination in step 9 is yes, then proceed to step 8. This power is the actual maximum power point of the photovoltaic array.

[0133] 11. If the judgment in step 9 is negative, return to step one.

[0134] This invention also provides a maximum power point tracking device based on the output characteristics of a photovoltaic array, such as... Figure 7 As shown, the photovoltaic array includes photovoltaic modules; the device includes:

[0135] The acquisition module 201 is used to acquire the output voltage and output current of the photovoltaic array and the first open-circuit voltage of the photovoltaic module; for details, please refer to the relevant description of step 101 in the above method embodiment.

[0136] The determination module 202 is used to determine the current-voltage characteristic curve and the output power characteristic curve of the photovoltaic array based on the output voltage and the output current; for details, please refer to the relevant description of step 102 in the above method embodiment.

[0137] The search module 203 is used to search the output power characteristic curve using the first open-circuit voltage as the search step size and the distribution principle of the local optima of the volt-ampere characteristic curve and the output power characteristic curve being uniformly distributed with the first open-circuit voltage as the base quantity, to obtain the first maximum power point; for details, please refer to the relevant description of step 103 in the above method embodiment.

[0138] The processing module 204 is used to obtain the target maximum power point of the photovoltaic array based on the first maximum power point and through particle swarm optimization algorithm; for details, please refer to the relevant description of step 104 in the above method embodiment.

[0139] The maximum power point tracking (MPPT) device based on the output characteristics of a photovoltaic (PV) array provided in this invention utilizes the characteristic that all local optima of the PV array's output power characteristic curve are located near integer multiples of the PV module's open-circuit voltage. That is, each local optima is uniformly distributed with the PV module's open-circuit voltage as a baseline. By searching the output power characteristic curve using the PV module's open-circuit voltage as the search step size, the global optimum of the output power characteristic curve, i.e., the first maximum power point, can be quickly located. Compared with traditional tracking methods, it eliminates the need to scan the entire PV array's output power characteristic curve, significantly improving the optimization speed. Simultaneously, it uses a particle swarm optimization algorithm for precise searching, obtaining the actual global optimum of the output power characteristic curve, i.e., the target maximum power point, avoiding the algorithm getting trapped in local optima. Furthermore, the search process utilizes the inherent characteristics of the PV array during operation, exhibiting universality and high reliability, and can be further applied to the promotion and use of PV power plants.

[0140] As an optional implementation of this invention, the acquisition module includes: a first acquisition submodule, used to acquire the second open-circuit voltage of the photovoltaic array and the number of series-connected cells in the photovoltaic array; and a first determination submodule, used to determine the first open-circuit voltage based on the second open-circuit voltage and the number of series-connected cells.

[0141] As an optional implementation of this invention, the search module includes: a second determining submodule, configured to determine an initial point voltage based on the first open-circuit voltage; a third determining submodule, configured to determine a maximum search voltage based on the initial point voltage, the first open-circuit voltage, and the number of series-connected batteries; a fourth determining submodule, configured to determine a search range based on the initial point voltage and the maximum search voltage; and a search submodule, configured to search within the search range on the output power characteristic curve using the first open-circuit voltage as the search step size, based on the current-voltage characteristic curve, to obtain the first maximum power point.

[0142] As an optional implementation of this invention, the search submodule includes: a second acquisition submodule for acquiring a first voltage of the photovoltaic array; a fifth determination submodule for determining a first current of the photovoltaic array in the current-voltage characteristic curve based on the first voltage; a sixth determination submodule for determining a first power of the photovoltaic array based on the first voltage and the first current; an update and acquisition submodule for updating the first voltage based on the search step size and acquiring the updated second voltage and second current of the photovoltaic array; a seventh determination submodule for determining a second power of the photovoltaic array based on the second voltage and the second current; a first comparison submodule for comparing the second power and the first power; an iterative update submodule for updating the first power using the second power and updating the first voltage using the second voltage when the second power is greater than the first power, until the second voltage iterates to the maximum search voltage and the iteration stops, thus obtaining a target voltage; and an eighth determination submodule for determining the first maximum power point in the output power characteristic curve based on the target voltage.

[0143] As an optional implementation of this invention, the search submodule further includes: a ninth determining submodule, configured to determine the first maximum power of the photovoltaic array based on the current-voltage characteristic curve, the maximum search voltage, and the second current when the second power is less than the first power; a second comparison submodule, configured to compare the first maximum power with the first power; a first repeating submodule, configured to repeat the steps of updating the first voltage based on the search step size and obtaining the updated second voltage and second current of the photovoltaic array to the step of determining the first maximum power point in the output power characteristic curve based on the target voltage when the first maximum power is greater than the first power; a first judging submodule, configured to judge whether the second power is equal to the first power when the first maximum power is less than and equal to the first power; and a tenth determining submodule, configured to take the power point corresponding to the second power as the first maximum power point when the second power is equal to the first power.

[0144] As an optional implementation of this invention, the processing module includes: an eleventh determining submodule, configured to determine a third voltage of the photovoltaic array based on the first maximum power point in the output power characteristic curve; a twelfth determining submodule, configured to determine an initialization voltage of each particle based on the third voltage; a calculation submodule, configured to calculate a first search power of each particle based on the initialization voltage of each particle; a thirteenth determining submodule, configured to determine a second maximum power and a third maximum power of the photovoltaic array based on each of the first search powers; an update and judgment submodule, configured to update the position and velocity of each particle and determine whether the second maximum power is equal to the third maximum power; a third acquisition submodule, configured to acquire a fourth voltage and a third current of the photovoltaic array when the second maximum power is equal to the third maximum power; a fourteenth determining submodule, configured to determine a third power of the photovoltaic array based on the fourth voltage and the third current; a second judgment submodule, configured to determine whether the third power meets a preset power range; and a fifteenth determining submodule, configured to take the power point corresponding to the second maximum power as the target maximum power point when the third power meets the preset power range.

[0145] As an optional implementation of the present invention, the processing module further includes: a second repeating submodule, used to repeat the step of calculating the first search power of each particle based on the initial voltage of each particle when the second maximum power is not equal to the third maximum power, until the third power satisfies the preset power range, and then take the power point corresponding to the second maximum power as the target maximum power point.

[0146] For a detailed description of the maximum power point tracking device based on the output characteristics of a photovoltaic array provided in this embodiment, please refer to the description of the maximum power point tracking method based on the output characteristics of a photovoltaic array in the above embodiments.

[0147] This invention also provides a storage medium, such as... Figure 8 As shown, a computer program 301 is stored thereon. When executed by a processor, this program implements the steps of the maximum power point tracking method based on the output characteristics of the photovoltaic array in the above embodiments. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium may also include combinations of the above types of memory.

[0148] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.

[0149] This invention also provides an electronic device, such as... Figure 9 As shown, the electronic device may include a processor 41 and a memory 42, wherein the processor 41 and the memory 42 may be connected via a bus or other means. Figure 9 Taking the example of a connection between China and Israel via a bus.

[0150] Processor 41 can be a central processing unit (CPU). Processor 41 can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations of the above types of chips.

[0151] The memory 42, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the corresponding program instructions / modules in the embodiments of the present invention. The processor 41 executes various functional applications and data processing by running the non-transitory software programs, instructions, and modules stored in the memory 42, thereby realizing the maximum power point tracking method based on the output characteristics of the photovoltaic array in the above method embodiments.

[0152] The memory 42 may include a program storage area and a data storage area. The program storage area may store applications required for operating the device and at least one function; the data storage area may store data created by the processor 41, etc. Furthermore, the memory 42 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 42 may optionally include memory remotely located relative to the processor 41, and these remote memories may be connected to the processor 41 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0153] The one or more modules are stored in the memory 42, and when executed by the processor 41, they perform actions such as... Figure 1-6 The maximum power point tracking method based on the output characteristics of the photovoltaic array is shown in the embodiment.

[0154] For specific details regarding the aforementioned electronic devices, please refer to the relevant documentation. Figures 1 to 6 The relevant descriptions and effects in the illustrated embodiments are for understanding purposes only and will not be repeated here.

[0155] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A maximum power point tracking method based on the output characteristics of a photovoltaic array, characterized in that, The photovoltaic array includes photovoltaic modules; the method includes: Obtain the output voltage and output current of the photovoltaic array and the first open-circuit voltage of the photovoltaic module; Based on the output voltage and the output current, determine the current-voltage characteristic curve and the output power characteristic curve of the photovoltaic array; Using the first open-circuit voltage as the search step size, and utilizing the distribution principle of the local optimum of the volt-ampere characteristic curve and the output power characteristic curve being uniformly distributed with the first open-circuit voltage as the base quantity, the search is performed in the output power characteristic curve to obtain the first maximum power point. Based on the first maximum power point, the target maximum power point of the photovoltaic array is obtained through particle swarm optimization. The process of obtaining the target maximum power point of the photovoltaic array based on the first maximum power point and through particle swarm optimization includes: Based on the first maximum power point, the third voltage of the photovoltaic array is determined in the output power characteristic curve; Based on the third voltage, the initial voltage of each particle is determined; Calculate the first search power for each particle based on the initial voltage of each particle; The second and third maximum power of the photovoltaic array are determined based on each of the first search power; Update the position and velocity of each particle, and determine whether the second maximum power is equal to the third maximum power; When the second maximum power equals the third maximum power, the fourth voltage and the third current of the photovoltaic array are obtained; Based on the fourth voltage and the third current, the third power of the photovoltaic array is determined; Determine whether the third power meets the preset power range; When the third power meets the preset power range, the power point corresponding to the second maximum power is taken as the target maximum power point.

2. The method according to claim 1, characterized in that, Obtaining the first open-circuit voltage of the photovoltaic module includes: Obtain the second open-circuit voltage of the photovoltaic array and the number of series-connected cells in the photovoltaic array; The first open-circuit voltage is determined based on the second open-circuit voltage and the number of series-connected batteries.

3. The method according to claim 2, characterized in that, Using the first open-circuit voltage as the search step size, and utilizing the distribution principle of the local optima of the volt-ampere characteristic curve and the output power characteristic curve being uniformly distributed with the first open-circuit voltage as the base quantity, a search is performed in the output power characteristic curve to obtain the first maximum power point, including: Determine the initial point voltage based on the first open-circuit voltage; The maximum search voltage is determined based on the initial point voltage, the first open-circuit voltage, and the number of series-connected batteries; The search range is determined based on the initial point voltage and the maximum search voltage; Within the search range, based on the current-voltage characteristic curve, the first maximum power point is obtained by searching the output power characteristic curve with the first open-circuit voltage as the search step size.

4. The method according to claim 3, characterized in that, Within the search range, based on the current-voltage characteristic curve, and using the first open-circuit voltage as the search step size, a search is performed on the output power characteristic curve to obtain the first maximum power point, including: Obtain the first voltage of the photovoltaic array; Based on the first voltage, the first current of the photovoltaic array is determined in the current-voltage characteristic curve; Based on the first voltage and the first current, the first power of the photovoltaic array is determined; The first voltage is updated based on the search step size, and the updated second voltage and second current of the photovoltaic array are obtained. The second power of the photovoltaic array is determined based on the second voltage and the second current; Compare the second power with the first power; When the second power is greater than the first power, the first power is updated using the second power and the first voltage is updated using the second voltage until the second voltage iterates to the maximum search voltage and the iteration stops, thus obtaining the target voltage. Based on the target voltage, the first maximum power point is determined in the output power characteristic curve.

5. The method according to claim 4, characterized in that, After comparing the second power and the first power, the method further includes: When the second power is less than the first power, the first maximum power of the photovoltaic array is determined based on the current-voltage characteristic curve, the maximum search voltage, and the second current. Compare the first maximum power with the first power; When the first maximum power is greater than the first power, repeat the steps of updating the first voltage based on the search step size and obtaining the updated second voltage and second current of the photovoltaic array to determine the first maximum power point in the output power characteristic curve based on the target voltage; When the first maximum power is less than and equal to the first power, determine whether the second power is equal to the first power; When the second power is equal to the first power, the power point corresponding to the second power is taken as the first maximum power point.

6. The method according to claim 1, characterized in that, After updating the position and velocity of each particle and determining whether the second maximum power is equal to the third maximum power, the method further includes: When the second maximum power is not equal to the third maximum power, the step of calculating the first search power of each particle based on the initial voltage of each particle is repeated until the third power meets the preset power range, and the power point corresponding to the second maximum power is taken as the target maximum power point.

7. A maximum power point tracking device based on the output characteristics of a photovoltaic array, characterized in that, The photovoltaic array includes photovoltaic modules; the device includes: The acquisition module is used to acquire the output voltage and output current of the photovoltaic array and the first open-circuit voltage of the photovoltaic module; The determination module is used to determine the current-voltage characteristic curve and the output power characteristic curve of the photovoltaic array based on the output voltage and the output current; The search module is used to search the output power characteristic curve with the first open-circuit voltage as the search step size, and to obtain the first maximum power point by utilizing the distribution principle of the local optima of the volt-ampere characteristic curve and the output power characteristic curve being uniformly distributed with the first open-circuit voltage as the base quantity. The processing module is used to obtain the target maximum power point of the photovoltaic array based on the first maximum power point and through particle swarm optimization algorithm. The processing module includes: an eleventh determining submodule, used to determine the third voltage of the photovoltaic array based on the first maximum power point in the output power characteristic curve; a twelfth determining submodule, used to determine the initial voltage of each particle based on the third voltage; a calculation submodule, used to calculate the first search power of each particle based on the initial voltage of each particle; a thirteenth determining submodule, used to determine the second maximum power and the third maximum power of the photovoltaic array based on each of the first search powers; an update and judgment submodule, used to update the position and velocity of each particle and determine whether the second maximum power is equal to the third maximum power; a third acquisition submodule, used to acquire the fourth voltage and the third current of the photovoltaic array when the second maximum power is equal to the third maximum power; a fourteenth determining submodule, used to determine the third power of the photovoltaic array based on the fourth voltage and the third current; a second judgment submodule, used to determine whether the third power meets a preset power range; and a fifteenth determining submodule, used to take the power point corresponding to the second maximum power as the target maximum power point when the third power meets the preset power range.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program for causing the computer to perform the maximum power point tracking method based on the output characteristics of a photovoltaic array as described in any one of claims 1 to 6.

9. An electronic device, characterized in that, include: The system includes a memory and a processor, which are communicatively connected to each other. The memory stores a computer program, and the processor executes the computer program to perform the maximum power point tracking method based on the output characteristics of a photovoltaic array as described in any one of claims 1 to 6.

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