Array structure design method for output power optimization at the efficiency threshold

Abstract

This invention relates to an array structure design method for optimizing output power at the efficiency threshold, belonging to the field of wireless power transfer technology. The method includes the following steps: S1: Output design of series-parallel components under non-uniform irradiation; S2: Establishing an irradiation uniformity algorithm for a static 3×3 laser cell array; S3: Establishing the optimal electrical connection structure under the irradiation uniformity algorithm. Based on the irradiation uniformity algorithm, the battery array under static projection is arranged and combined. Combining the advantages of TCT, series, and parallel structures, a composite improved TCT structure is proposed. A laser wireless power receiving system model is established, and simulation examples demonstrate that this structure can effectively reduce the mismatch loss of the laser cell array, increase the output power of the laser cell, reduce multi-peaks, and thus alleviate the difficulty of subsequent MPPT optimization.

Description

Technical Field

[0001] This invention belongs to the field of wireless power transmission technology and relates to an array structure design method for optimizing output power at the efficiency threshold. Background Technology

[0002] Wireless power transfer technology has a wide range of applications in the aerospace field. It can provide advanced and flexible energy acquisition methods for space science research, space-based remote sensing, and environmental monitoring, meeting the needs of various major applications and making remote sensing and space science research more convenient and efficient. Driven by aerospace applications, wireless power transfer technology can not only be used in space applications such as space solar power stations, but also in various wireless power transfer applications such as air-to-ground, air-to-air, and ground-based connections. This expands the application scope and modes of various power-consuming devices and facilities, including drones, wireless sensors, and fast charging, demonstrating broad application prospects and significant economic benefits.

[0003] To enhance the application of this technology in the aerospace field and improve the endurance of electric drones, laser wireless power transfer technology has gained significant attention. A laser wireless power transfer system mainly includes a laser emitting module, a laser receiving module, an energy management module, and a load. At the receiving end of a wireless laser power transfer (WLPT) system, the non-uniform Gaussian distribution of incident laser energy causes electrical mismatch between the laser cells in the laser array, reducing the array's output power and significantly limiting system efficiency. Simultaneously, the array's output power-output voltage (PV) characteristics exhibit multi-peak features, causing the failure of traditional maximum power point tracking (MPPT) control technology. The non-uniform laser irradiation causes severe energy loss at the receiving end of the wireless laser power transfer system; experimental measurements show energy losses as high as 78%, greatly limiting the practical application of laser wireless power transfer technology.

[0004] Non-uniform Gaussian incident laser light reduces the photoelectric conversion efficiency of the battery array, necessitating research into the relationship between uniformity and circuit efficiency. While studying different focusing ratios can improve illumination non-uniformity, the focusing devices in actual components cannot achieve perfectly uniform illumination. Increasing the spot coverage can reduce the impact of illumination non-uniformity on battery efficiency, but this prevents all light energy from being concentrated on the battery. Non-uniform irradiation is a problem that cannot be completely solved; only by studying the intrinsic relationship between uniformity and circuit efficiency can the photoelectric conversion efficiency of the laser wireless energy transmission system receiver be improved. Literature records that analyzing the relationship between the efficiency of series-parallel components of two batteries and illumination non-uniformity reveals that the circuit efficiency of the parallel component is consistently greater than that of the series component as illumination uniformity changes. However, actual simulations show that the series output power is greater than the parallel output power under different uniformity conditions, requiring further research on multiple batteries or arrays. Furthermore, existing algorithms based on irradiance uniformity lack theoretical basis for calculating non-uniform irradiation in the application of Gaussian beams. Therefore, it is necessary to study the impact of the uniformity of the light spot received by multiple batteries on the circuit efficiency under the Gaussian distribution law.

[0005] Optimizing the electrical connection structure of a laser cell array can improve its photoelectric conversion efficiency. The core idea is to adjust the distribution of uneven illumination within the electrical structure of the laser cell array through different series and parallel connection methods, while meeting the system's operating voltage and current requirements. This reduces mismatch and improves the array's conversion efficiency. Existing photovoltaic array efficiency optimization technologies mainly include electrical structure reconstruction technology and the use of correction circuits and global MPPT technology. Since the energy distribution of the laser spot has certain regularity and stability, current LPT technology research mainly focuses on optimizing the electrical structure of the laser cell array to achieve higher conversion efficiency. Numerous studies have shown that, compared to series-parallel (SP) and bridge-linked (BL) structures, the TCT structure can better solve the power loss problem caused by mismatch between photovoltaic cells under uneven irradiation. Currently, TCT structures mainly include TCT structure reconstruction methods, bias voltage correction methods, and the use of GCC (Generation Control Circuit) circuits to improve the efficiency of series-connected photovoltaic arrays. Bias voltage correction methods introduce a converter in each branch to provide bias voltage. A GCC based on a multi-stage chopper is essentially a series of series-connected Boost converters, with each photovoltaic module connected in parallel to one output of the full-bridge converter, thus ensuring equal output voltage for each module. However, these methods are circuitically complex and unsuitable for practical applications. Furthermore, effective methods and theories to guide the electrical layout of laser cell arrays in practical applications are still lacking. Therefore, it is necessary to study, based on the theories of uniformity and circuit efficiency, an optimal electrical connection method for laser cell array efficiency under Gaussian laser irradiation needs to be proposed.

[0006] The above analysis shows that the efficiency of series-parallel component circuits is closely related to the uniformity of the laser beam. However, few scholars have proposed the boundary point between series and parallel connections for laser cell arrays under different uniformities, lacking effective methods and theories to guide the establishment of algorithms for finding the optimal electrical connection structure. This invention studies the influence of coverage and irradiance uniformity on circuit efficiency under Gaussian beams. Based on the efficiency boundary point of the connection structure, this condition is extended to a 3×3 laser cell array. According to the characteristics of multiple cells under different uniformities, an electrical connection structure algorithm matching the irradiance uniformity is established. When special requirements are met, either all cells are connected in series or in parallel. The electrical connection structure designed under other conditions combines the advantages of TCT, series, and parallel structures. A new combination with a TCT structure as the main component is proposed, suitable for algorithms with relatively uniform irradiance. The remaining cells with lower irradiance are connected in series to increase the voltage at the maximum output power point. Finally, the two structures are combined in parallel. This allows cells with lower irradiance uniformity to achieve common output and high efficiency. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide an array structure design method for optimizing output power at the efficiency threshold. In laser wireless power transmission systems, non-uniform irradiation is one of the key factors affecting photoelectric conversion efficiency. Changing the electrical connection structure of the laser cell array can reduce the adverse effects of non-uniform irradiation. Based on this, this invention establishes a laser power transmission system model, studies the relationship and underlying mechanism between the efficiency of multi-cell series-parallel connection components and irradiation uniformity, obtains the efficiency threshold for three cells connected in series and parallel under Gaussian beam characteristics, and proposes an algorithm for the optimal electrical connection structure for different irradiation uniformities based on a 3×3 laser cell array under Gaussian beam characteristics. Based on the above algorithm, an improved total-cross-tie (TCT) structure for the laser cell array is proposed. Simulation examples demonstrate that this structure can effectively reduce the mismatch loss of the laser cell array, increase the output power of the laser cell, reduce multi-peaks, and thus alleviate the difficulty of subsequent MPPT optimization.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for optimizing output power of an array structure at the efficiency threshold, comprising the following steps:

[0010] S1: Output design of series-parallel components under uneven irradiation;

[0011] S2: Establish an algorithm for the uniformity of irradiation of a static 3×3 laser cell array;

[0012] S3: Establish the optimal electrical connection structure under the irradiance uniformity algorithm.

[0013] Optionally, S1 specifically includes:

[0014] S11: Output design of a series-parallel assembly of two batteries under uneven irradiation;

[0015] The circuit efficiency η of the battery module is defined as the ratio of the maximum output power of the module under non-uniform illumination conditions to the sum of the maximum output power of all laser cells in the battery module, as shown in equation (1):

[0016]

[0017] In the formula: P M P represents the maximum power output of the battery module under uneven irradiation conditions. i denoted as the maximum output power of the i-th laser cell; N is the number of laser cells; the uniformity α of the light intensity distribution is measured by the ratio of the irradiance received by PV2 to the light intensity received by PV1.

[0018] When the uniformity of illumination is approximately 0.4, the power loss is greatest in the series configuration, with the lowest circuit efficiency at 68.62%. When the uniformity is 0, the illumination uniformity is poor, and in the series configuration, only PV1 with higher irradiance outputs power, while PV2 suffers efficiency loss. The stronger the irradiance received by PV2, the greater its power consumption, and the lower the component's circuit efficiency. In the middle section, the illumination uniformity increases, and both PV1 and PV2 output power. The greater the illumination uniformity, the further PV1 deviates from its maximum power point, resulting in greater power loss and lower circuit efficiency. Finally, the higher the uniformity of the light intensity received by PV1 and PV2, the closer the laser cell is to its maximum power point, and the higher the circuit efficiency. Under uniform irradiation, there is no loss, and the circuit efficiency is at its maximum of 100%. When the uniformity is 0 or 1, the circuit efficiency of the series configuration intersects with that of the parallel configuration.

[0019] S12: Analysis of the Relationship between Series-Parallel Components of Multiple Batteries and Light Spot Coverage under Non-uniform Irradiation

[0020] Gaussian laser irradiation is characterized by strong irradiation in the center and weak irradiation around the edges, exhibiting the following pattern:

[0021]

[0022] r b =2λRβ / πd t (3)

[0023] Where f0 is the energy ratio of the beam emitted through the beam pointer, f a P represents the energy ratio of a beam emitted perpendicularly through the atmosphere, θ is the angle of inclination of the beam to the vertical axis, and P is the energy ratio of the beam emitted perpendicularly through the atmosphere. L Let β be the total laser energy, and I be the beam quality coefficient. rel d is the Strehl ratio, λ is the emitted laser wavelength; t The aperture of the launching telescope;

[0024] Set the center position to 1000W / m 2 The laser power formula is derived to determine the irradiation distance; the irradiance of each battery is obtained by setting the receiving area of ​​each battery, and the three batteries are calculated. When the irradiance of the battery at the edge is approximately 0, the coverage rate is defined as 100%. The coverage rate is defined based on the receiving area. Under the Gaussian distribution law, without load, considering the battery internal resistance and the consumption of the protection diode, the spot coverage rate S is calculated by the receiving area. The value of the spot coverage rate S ranges from 1 to 0 and is divided into 12 groups. The radiation intensity of the three batteries is calculated by formula (2). The three batteries are connected in parallel and the output power is measured. When the spot coverage rate is equal to 1, the Gaussian distribution irradiance on the laser battery is 1000W / m. 2 87.47W / m 2and 0.058W / m 2 When connected in parallel, the total output power is 319.4W, and the maximum power point voltage is V. max =51.57V; At this time, the output power of a single battery is: PV1=303.1W, PV2=24.7W and PV3=0.078W; The corresponding maximum power point voltages are V1=54.87V, V2=51.57V and V3=36.67V; According to formula (1), the circuit efficiency η is calculated to be 97.43%;

[0025] The maximum output power increases with increasing irradiance intensity; when the irradiance intensity is greater than 677.18 W / m², the maximum output power increases. 2 When the maximum power point voltage changes less, a series connection is selected; when the maximum power point voltage is close, multiple batteries are connected in series to output power together; the maximum output power of a single battery at different irradiation intensities is applicable to both series and parallel circuit efficiency calculations.

[0026] The light spot coverage P ranges from 0 to 1. When the light spot coverage S equals 0, the irradiance received by the three batteries is equal, and the uniformity α is at its maximum of 1. The edge uniformity α is defined as the ratio of the battery with the lowest irradiance to the battery with the highest irradiance among the three batteries, as shown in the following formula:

[0027]

[0028] In formula (3), P1 represents the irradiance of 1000 W / m². 2 Among the three batteries, P3 has the lowest irradiance.

[0029] When the light spot coverage is greater than 0.1, the efficiency of the series circuit is significantly lower than that of the parallel circuit; when the light spot coverage is equal to 0.1, the efficiency of the series connection structure exceeds that of the parallel connection structure for the first time, at which point the edge uniformity α is equal to 0.9; when the three batteries receive Gaussian-distributed irradiation, when the irradiation uniformity is greater than 0.9, the efficiency of the series connection structure is greater than that of the parallel connection structure.

[0030] When there is a combination of three batteries, and the edge irradiance uniformity is above 0.9 or the spot coverage is less than 0.1, the series connection structure can improve the circuit efficiency. When applied to a 3×3 laser battery array in a static laser wireless energy transmission system, the optimal electrical connection structure is found for different uniformities.

[0031] Optionally, S2 specifically includes:

[0032] The electrical layout of the 3×3 laser cell array is analyzed, and the specific process is as follows:

[0033] S21: Input spot diameter d = t;

[0034] S22: Input laser cell length x cm, width y cm. The following study assumes x = y.

[0035] S23: Taking the center of the light spot as the origin, let the horizontal coordinate of the battery at the center position be m1 = 0 and the vertical coordinate be n1 = 0, the horizontal coordinate of the battery at the second type of same power position be m2 = x and the vertical coordinate be n2 = 0, and the horizontal coordinate of the battery at the third type of same power position be m3 = x and the vertical coordinate be n3 = y.

[0036] S24: Distance from the center of the light spot: D1=0, D2=|x|,

[0037] S25: Set the power at the center of the laser spot to S1, which is located at the center of the laser spot; Substitute D2 and D3 into the simplified formula for laser power to calculate S2 and S3;

[0038] In a 3×3 TCT laser cell array structure, (0, 0) is the origin, x is the abscissa, and y is the ordinate; PV x,y The corresponding coordinates are the battery; x = y, and the center of the laser irradiation spot is located at PV. 0，0 The laser cell array has only three power levels: S1, S2, and S3.

[0039] Optionally, in the TCT structure of the laser cell array, when the photovoltaic array of the TCT structure is optimized under Gaussian laser irradiation, the number of subarrays in the array remains unchanged before and after optimization, but the number of photovoltaic cells connected in parallel in different subarrays is inconsistent.

[0040] The quality of the electrical connection method of the TCT structure is judged by comparing the difference in irradiance between the two subarrays with the largest and smallest sum of irradiance. The smaller the difference in irradiance, the better the uniformity of irradiance received by each subarray in the structure, and the better the electrical connection method.

[0041] Optionally, in the laser wireless energy transmission system of the 3×3 laser battery array in a static scene, the specific process of finding the corresponding optimal electrical connection structure for different uniformities is as follows:

[0042] S121: Determine and sort the irradiance S1, S2, and S3 of the individual cells in the array;

[0043] By inputting the beam diameter, the length and width of the laser cell, and the power at the center of the beam, the irradiance S1, S2, and S3 of each cell in the array are calculated. The laser cells are then arranged in sequence A according to the light intensity received, from largest to smallest.

[0044] PV 0，0 =S1>PV x,0 =PV-x,0 =PV 0,y =PV 0,-y =S2 (5)

[0045] S2>PV x,y =PV -x,y =PV x,-y =PV -x,-y =S3 (6)

[0046] The TCT structure of a 3×3 laser cell array has three subarrays, each composed of cells with equal irradiance. To ensure that the sum of irradiance received by each subarray is as equal as possible, the sum of irradiance received by each subarray is first calculated and then arranged in ascending order to form a subarray sequence M, such as...

[0047] G M1 ≤G M2 ≤G M3 (7)

[0048] Next, the battery cells inside the subarrays in M ​​are connected in parallel, and the subarrays are connected in series to form the basic array T0; this array is connected in a TCT structure.

[0049] Select the cell element T with the highest and lowest light intensity in T0. 0max ', T 0min The light intensities at the corresponding structural boundary points are G, respectively. 0max and G 0min Calculate the difference in light intensity ΔG under the condition of their boundary point. d ;like:

[0050] G 0max =0.9T 0max (8)

[0051] G 0min =T 0min (9)

[0052] ΔG d =G 0min -G 0max (10)

[0053] If ΔG d If the value is greater than 0, then replace T0 with the new array T1;

[0054] Take T 0max The battery element and T 0min Battery cell T with slightly stronger light intensity mid For comparison, the light intensities at the upper and lower boundary points of the corresponding structures are G, respectively. 0max 'and G 0min 'Calculate the difference in light intensity ΔG under the condition of their boundary point.d ';

[0055] Increase T sequentially 0min Medium light intensity ratio T 0max Slightly weaker battery element T mid The light intensity difference ΔG between them is calculated based on the boundary point condition. imax ΔG imin ,i indicates that the irradiance is located at T 0min With T 0max between i battery cells;

[0056] ΔG imax =|T mid -1 / 0.9×T 0max | (11)

[0057] ΔG imin =T mid -0.9×T 0max (12)

[0058] G i =i×T mid (13)

[0059] If there are a total of i battery cells, then ΔG is satisfied. imin If the condition is greater than 0, then block T of type i will be... mid The battery cells are combined, and the sum of the irradiance is G. i T 0min The battery cells are connected in parallel to form a new subarray T. i If none of them satisfy G 0max >G i >G 0min ;

[0060] The battery array output is connected to the MPPT and boost circuit. The MPPT circuit can match the internal resistance to enable the battery array to operate at maximum power.

[0061] The beneficial effects of this invention are as follows:

[0062] This invention, based on a laser wireless power transmission system and boost circuit model, aims to optimize the photoelectric conversion efficiency of the laser cell. It addresses the power reduction issue caused by a Gaussian-distributed laser source under static projection under different irradiance uniformities. The relationship and underlying mechanism between the efficiency of a multi-cell series-parallel connection and irradiance uniformity are investigated. The efficiency boundary between series and parallel connections of three cells under Gaussian beam characteristics is obtained. Based on a 3×3 laser cell array under Gaussian beam characteristics, an optimal electrical connection structure algorithm is proposed for different irradiance uniformities. Based on this algorithm, an improved Total-Cross-Tie (TCT) structure for the laser cell array is proposed to maximize photoelectric conversion efficiency. The main conclusions are as follows:

[0063] (1) The relationship between the efficiency of the series-parallel connection of the three batteries and the uniformity of illumination is as follows: when the edge irradiance uniformity is above 0.9 or the light spot coverage is less than 0.1, under this boundary condition, the series connection structure can improve the circuit efficiency.

[0064] (2) Compared with the traditional irradiation uniformity algorithm, this invention proposes a corresponding laser cell array connection structure for different irradiation uniformities. Based on the efficiency boundary point of series and parallel components, the optimal electrical connection method of the laser cell under different irradiation uniformities can be effectively determined.

[0065] (3) Based on the irradiance uniformity algorithm, the 33-cell array under static projection is arranged and combined. Combining the advantages of TCT structure, series structure and parallel structure, a composite improved TCT structure is proposed. A laser wireless energy receiving system model is established. Through simulation examples, it is proved that the structure can effectively reduce the mismatch loss of the laser cell array, increase the output power of the laser cell, reduce multi-peaks, and thus reduce the difficulty of subsequent MPPT optimization.

[0066] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0067] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0068] Figure 1 The relationship between voltage and power under different irradiation conditions;

[0069] Figure 2 The relationship between current and power under different irradiations;

[0070] Figure 3 The relationship between efficiency and uniformity of series-parallel component circuits;

[0071] Figure 4 PU curves for different spot coverage rates in parallel structures;

[0072] Figure 5 PU curves for different spot coverage rates in a series structure;

[0073] Figure 6 The relationship between the efficiency of series and parallel components and the light spot coverage;

[0074] Figure 7 It is a 3×3 laser cell array TCT structure;

[0075] Figure 8 To improve the optimization and reconstruction algorithm of the TCT structure;

[0076] Figure 9 This represents the maximum output power under the algorithm of uniform irradiance without radiation.

[0077] Figure 10 This represents the maximum output power under the uniform irradiance algorithm.

[0078] Figure 11 PU output characteristic curves for different laser cell array configurations in static projection mode;

[0079] Figure 12 UI output characteristic curves for different laser cell arrays configured in static projection mode;

[0080] Figure 13 To improve the circuit diagram of the TCT laser battery system;

[0081] Figure 14 A comparison of the output power of parallel connection and improved TCT structure under equal voltage conditions. Detailed Implementation

[0082] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0083] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0084] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0085] 1. Output characteristics of series-parallel components under uneven irradiation

[0086] 1.1 Output characteristics of a series-parallel assembly of two batteries under non-uniform irradiation

[0087] When the array irradiance non-uniformity is small, i.e., near uniform irradiance, the maximum output power of the array is high because most of the laser cells in the array have similar irradiance levels and can operate near their respective maximum power points, resulting in less mismatch loss. Conversely, when the array irradiance non-uniformity is large, the maximum output power is higher because most of the incident light energy is converted and output from the more intensely irradiated laser cells. Essentially, this is also due to the reduction in mismatch loss, which increases the array's output power.

[0088] like Figure 1 and Figure 2 As shown, the maximum power point voltage in the power curve of the component changes very little under different illumination conditions. This is because the open-circuit voltage of the laser cell has a logarithmic relationship with the light intensity and is less affected by the light intensity. When PV1 and PV2 operate under significantly different irradiance conditions, it is best to connect them in parallel to maintain the same maximum power point voltage.

[0089] To better describe the power loss caused by the laser cells in the series-parallel components deviating from their maximum power point under non-uniform illumination, the circuit efficiency η of the battery module is defined as the ratio of the maximum output power of the module under non-uniform illumination to the sum of the maximum output power of all laser cells in the battery module, as shown in equation (1):

[0090]

[0091] In the formula: P M P represents the maximum power output of the battery module under uneven irradiation conditions. i Let be the maximum output power of the i-th laser cell; N be the number of laser cells. The uniformity α of the light intensity distribution is measured by the ratio of the irradiance received by PV2 to the light intensity received by PV1. Figure 3 The relationships between the circuit efficiency of series components and the circuit efficiency of parallel components and the uniformity of illumination are given respectively.

[0092] from Figure 3 As can be seen, when the illumination uniformity is approximately 0.4, the power loss is greatest in the series configuration, resulting in the lowest circuit efficiency of 68.62%. When the uniformity is 0, the illumination uniformity is poor, and in the series configuration, only PV1 with higher irradiance outputs power, while PV2 suffers efficiency loss. The stronger the irradiance received by PV2, the greater its power consumption, and the lower the component's circuit efficiency. In the middle section, as the illumination uniformity increases, both PV1 and PV2 output power. However, PV1 deviates from its maximum power point; the greater the illumination uniformity, the further PV1 deviates from its maximum power point, resulting in greater power loss and lower circuit efficiency. Finally, when the uniformity of light intensity received by PV1 and PV2 is relatively high, the laser cells gradually approach their maximum power point, and the circuit efficiency increases. Under uniform irradiation, there is no loss, and the circuit efficiency reaches a maximum of 100%. Only when the uniformity is 0 or 1 does the circuit efficiency of the series configuration intersect with that of the parallel configuration. This indicates that under non-uniform illumination, using a parallel structure for two cells yields higher circuit efficiency.

[0093] However, actual simulation analysis revealed that when using a structure where all laser cells are connected in series versus a structure where all cells are connected in parallel in the array, the output power of the series structure is sometimes greater than that of the parallel structure. To address this issue, the relationship between circuit efficiency and coverage under Gaussian power distribution for multiple cells was analyzed.

[0094] 1.2 Relationship between series-parallel connection of multiple cells and light spot coverage under non-uniform irradiation

[0095] The non-uniform irradiation characteristics largely determine the output characteristics of laser cells. Therefore, when studying the relationship between irradiation uniformity and the output characteristics of series-parallel laser cell modules, it is essential to determine the irradiance on each individual laser cell in the laser array. Gaussian laser irradiation is characterized by strong irradiance in the center and weak irradiance around the edges, exhibiting the following pattern:

[0096]

[0097] r b =2λRβ / πd t (3)

[0098] Where f0 is the energy ratio of the beam emitted through the beam pointer, f a P represents the energy ratio of a beam emitted perpendicularly through the atmosphere, θ is the angle of inclination of the beam to the vertical axis, and P is the energy ratio of the beam emitted perpendicularly through the atmosphere. L Let β be the total laser energy, and I be the beam quality coefficient. rel d is the Strehl ratio, λ is the emitted laser wavelength; t The aperture of the launching telescope.

[0099] Set the center position to 1000W / m 2 The laser power formula is derived to determine the irradiation distance. By setting the receiving area of ​​each battery, the irradiance of each battery is obtained. This invention performs simulation calculations on three batteries. When the irradiance of the battery at the edge is approximately 0, the coverage rate is defined as 100%. Thereafter, the coverage rate is defined based on the receiving area. The battery array exhibits different output characteristics under different uniformity conditions. Under Gaussian distribution, without load, considering battery internal resistance and protection diode consumption, the output characteristics of the series and parallel structures of multiple batteries are analyzed as shown in Table 1.

[0100] Table 1. Relationship between light spot coverage and circuit efficiency in a multi-battery parallel structure.

[0101]

[0102] As shown in Table 1, the spot coverage S is calculated based on the receiving area. The value of spot coverage S ranges from 1 to 0 and is divided into 12 groups. The radiation intensity of the three batteries is obtained by simplifying the calculation using formula (2). Through simulation, the three batteries are connected in parallel and the output power is measured. For example, in group 1, when the spot coverage is equal to 1, the Gaussian irradiance on the laser battery is 1000 W / m². 2 87.47W / m 2 and 0.058W / m 2 When simulated in parallel, the total output power is 319.4W, and the maximum power point voltage V0 is... max =51.57V. At this time, the output power of a single battery is: PV1 = 303.1W, PV2 = 24.7W and PV3 = 0.078W. The corresponding maximum power point voltages are V1 = 54.87V, V2 = 51.57V and V3 = 36.67V. The circuit efficiency η is calculated according to formula (1), and the circuit efficiency is 97.43%. The calculation of circuit efficiency requires the maximum output power of a single battery under different irradiations. The output power of a single battery is shown in Table 2.

[0103] Table 2 Output characteristics of a single cell under different irradiation intensities

[0104]

[0105] As shown in Table 2, the maximum output power increases with increasing irradiance, and the voltage increase at the maximum power point is initially rapid and then slows down, providing a reference for analyzing electrical connection structures. When the irradiance exceeds 677.18 W / m², the maximum output power increases. 2 When the maximum power point voltage changes less, series connection becomes more feasible. Only when the maximum power point voltages are close can multiple batteries connected in series output power together. The maximum output power of a single battery at different irradiation intensities can be used for both series and parallel circuit efficiency calculations. To analyze the output characteristics of the parallel structure, the PU curve output characteristics of all groups under the three-battery parallel structure are statistically analyzed, such as... Figure 4 As shown.

[0106] from Figure 4 As can be seen from P i This corresponds to the i-th group in Table 1. At this time, P1 corresponds to group 1 in Table 1, with an output power of 319 W and V. max =51.57V, located at Figure 4 At the bottom of the spectrum. Under Gaussian irradiation, the power curve of the parallel components does not exhibit multi-peak behavior. This is because the open-circuit voltage of the laser cell has a logarithmic relationship with the irradiation, making it less affected by uneven irradiation. When the parallel components are at their maximum power operating point, the maximum power operating points of PV1, PV2, and PV3 are all close, allowing for simultaneous output and high circuit efficiency. Starting from P1, the output power continuously increases, and the efficiency remains above 97%. However, the parallel components have a very low output voltage and a large output current, which increases resistance losses. In practical situations, with a load present and a large parallel output current, the power loss will be greater than currently analyzed.

[0107] The relationship between light spot coverage and circuit efficiency in a multi-cell series structure is shown in Table 3.

[0108] Table 3. Relationship between light spot coverage and circuit efficiency in a multi-cell series connection structure.

[0109]

[0110] Table 3 shows that the radiation intensity received by the batteries in the series connection structure is consistent with that in the parallel connection structure, divided into 12 groups. Unlike the parallel connection structure, the circuit efficiency in the series structure shows a trend of first decreasing and then increasing, with the maximum power point voltage continuously increasing from 51.17V to 162.3V. Furthermore, the circuit efficiency reaches 98.35% in group 10, exceeding that of the parallel connection structure for the first time, at which point the spot coverage is equal to 0.1. This indicates that, considering the internal resistance of the laser battery, under a certain uniformity, the circuit efficiency of the series connection structure may be greater than that of the parallel connection structure. In practical situations, there is a load, and the parallel output current is larger, resulting in greater power loss. Therefore, if the radiation coverage S received by the battery is less than 0.1 or the uniformity is greater than 0.9, using a series connection can increase the circuit efficiency. To analyze the output characteristics of the series structure, the PU curve output characteristics of all groups under the three-battery series structure are statistically analyzed, such as... Figure 5 As shown.

[0111] from Figure 5 It can be seen that P i Corresponding to group i in Table 3, P1 is the PU output curve of group 1 in Table 3. In the PU curves of groups P1, P2, and P3, the irradiance received by battery 3 is too low, resulting in almost no output; therefore, the third band is almost zero. In groups P1, P2, P3, and P4, as the irradiance of batteries 2 and 3 increases, the second peak increases. Furthermore, the output waveforms of batteries 1 and 2 gradually approach each other but do not cross-output. In group P5, battery 3 begins to output, but batteries 1 and 2 still do not cross-output. In group P6, the second peak of the PU curve exceeds the first peak, and batteries 1 and 2 cross-output for the first time. V max Shift to the right. The waveforms of batteries P7 and P8 gradually converge, with the waveform of battery I almost completely obscured by the waveform of battery II. P max Gradually increasing. The waveforms of cells two and three in group P9 intersect, with the peak first appearing in cell three. P 10 The groups almost merge into a single peak, with a slight divergence at one point. P 11 The three batteries in the group output power in a cross-pollination manner, resulting in a single peak. This indicates that under conditions of poor uniformity, multiple batteries with different maximum power operating point voltages will not be able to output power together, resulting in a multi-peak output curve, which will make subsequent optimization difficult. Only when there is a certain degree of uniformity can multiple batteries under different irradiation intensities output power together.

[0112] The above analysis reveals a boundary between the circuit efficiencies of series and parallel connection structures. Therefore, analyzing both series and parallel connection structures together, and considering their impact on circuit efficiency under different light spot coverage rates, is crucial. Figure 6 As shown.

[0113] Depend on Figure 6 As can be seen, the light spot coverage P ranges from 0 to 1. When the light spot coverage S equals 0, the irradiance received by the three batteries is equal, and the uniformity α is at its maximum of 1. The edge uniformity α is defined as the ratio of the battery with the lowest irradiance to the battery with the highest irradiance, as shown in the following formula:

[0114]

[0115] In formula (3), P1 represents the irradiance of 1000 W / m². 2 Among the three batteries, P3 has the lowest irradiance.

[0116] When the light spot coverage is greater than 0.1, the efficiency of the series circuit is significantly lower than that of the parallel circuit. When the light spot coverage is equal to 0.1, the efficiency of the series connection structure exceeds that of the parallel connection structure for the first time, at which point the edge uniformity α equals 0.9. It can be found that when three batteries receive Gaussian-distributed irradiation, when the irradiation uniformity is above 0.9, the efficiency of the series connection structure is greater than that of the parallel connection structure.

[0117] Based on the above analysis, when there is a combination of three batteries and the edge irradiance uniformity is above 0.9 or the spot coverage is less than 0.1, a series connection structure can improve circuit efficiency. Applying this principle to a 3×3 laser battery array in a static laser wireless energy transmission system, the optimal electrical connection structure can be found for different uniformities.

[0118] 2. Algorithm for Irradiation Uniformity of Static 3×3 Laser Cell Array

[0119] Compared to the complex and randomly changing sunlight environment, the distribution of laser irradiance intensity follows a Gaussian distribution, exhibiting a certain regularity. Therefore, under a given spot coverage, the irradiance intensity on each photovoltaic cell in the array remains constant. This implies that under Gaussian laser irradiation, there must exist an optimal electrical connection structure for the photovoltaic array. Under fixed irradiance, for a TCT structure, changing the position of each photovoltaic cell within the array's electrical structure can yield different output characteristics. Therefore, to find the optimal electrical layout, this invention proposes an improved optimal electrical layout search algorithm for the TCT structure. This algorithm determines the position of each laser cell within the array's electrical structure, thereby constructing the TCT structure with the highest output power. The maximum output power of the optimized structure is then used as the optimal electrical layout for the laser cell array to achieve the maximum power output of the laser cell array.

[0120] The electrical layout of a 3×3 laser cell array is analyzed, focusing on the case where three power levels are fixed, the maximum power is unique, and it is located at the center. Figure 7As shown, the specific process is as follows:

[0121] 1. Input the diameter of the light spot, d = t;

[0122] 2. Given a laser cell with length x cm and width y cm, the following study assumes x = y.

[0123] 3. Taking the center of the light spot as the origin, let the horizontal coordinate of the battery at the center be m1 = 0 and the vertical coordinate be n1 = 0, the horizontal coordinate of the battery at the second type of same power position be m2 = x and the vertical coordinate be n2 = 0, and the horizontal coordinate of the battery at the third type of same power position be m3 = x and the vertical coordinate be n3 = y.

[0124] 4. Distance from the center of the light spot: D1 = 0, D2 = |x|,

[0125] 5. Set the power at the center of the laser spot to S1, which is located at the center of the spot. Substitute D2 and D3 into the simplified formula for laser power to calculate S2 and S3.

[0126] like Figure 7 In the 3×3 TCT laser cell array structure shown, (0, 0) is the origin, x is the horizontal coordinate, and y is the vertical coordinate. PV x,y Let x be the battery at the corresponding coordinate position. At this time, x = y, and the center of the laser irradiation spot is located at PV. 0，0 The laser battery array has only three power levels: S1, S2, and S3.

[0127] In such Figure 7 In the 3×3 photovoltaic array TCT structure shown, each row has three photovoltaic cells connected in parallel to form a subarray, and the three subarrays are connected in series to form the final TCT structure. If these subarrays are considered as the smallest unit for photoelectric conversion in the TCT structure, then the photovoltaic array TCT structure is essentially a single-string array. Therefore, to maximize the output power of the TCT structure, the principle of irradiance equalization should be satisfied, that is, the photovoltaic cells in different subarrays should be exchanged accordingly so that the sum of the irradiance intensity received by each photovoltaic cell in each subarray is as equal as possible (i.e., ensuring that the photogenerated current or maximum power point current of each subarray is as consistent as possible).

[0128] Obviously, for Figure 7 The TCT photovoltaic array structure shown clearly has more than one electrical connection method. Besides being composed of three subarrays connected in series, it could also be composed of one or two subarrays connected in series. Since the subsequent converter of the laser cell array is generally designed with an input voltage of mV... Mpp Optimized design was implemented. Therefore, for ease of discussion, this invention stipulates that:

[0129] (1) When optimizing the photovoltaic array of TCT structure under Gaussian laser irradiation, the number of subarrays in the array remains unchanged before and after optimization, but the number of photovoltaic cells connected in parallel in different subarrays may be inconsistent.

[0130] (2) The quality of the electrical connection method of the TCT structure can be judged by comparing the difference in irradiance between the two subarrays with the largest and smallest sum of irradiance. That is, the smaller the difference in irradiance, the better the uniformity of irradiance received by each subarray in the structure, and the better the electrical connection method.

[0131] The algorithm flow is as follows Figure 8 As shown. The main idea of ​​this algorithm is as follows: First, a basic array is quickly constructed using simple sorting and comparison methods. Then, certain subarrays within this basic array are further optimized through comparison and adjustment. This allows for finding a more efficient electrical connection method for the TCT array within an acceptable timeframe.

[0132] like Figure 8 As shown, the specific process of the optimized reconstruction algorithm for the improved TCT structure of a 3×3 laser cell array under static laser irradiation is as follows:

[0133] 1. Determine and sort the irradiance S1, S2, and S3 of the individual cells in the array.

[0134] By inputting the beam diameter, the length and width of the laser cell, and the power at the center of the beam, the irradiance S1, S2, and S3 of each cell in the array are calculated. The laser cells are then arranged in sequence A according to the light intensity received, from largest to smallest.

[0135] PV 0，0 =S1>PV x,0 =PV -x,0 =PV 0,y =PV 0,-y =S2 (5)

[0136] S2>PV x,y =PV -x,y =PV x,-y =PV -x,-y =S3 (6)

[0137] 2. Based on the above constraints, the TCT structure of a 3×3 laser cell array has three subarrays, each composed of cells with equal irradiance. To ensure that the sum of irradiance received by each subarray is as equal as possible, the sum of irradiance received by each subarray is first calculated and arranged in ascending order to form a subarray sequence M, such as...

[0138] G M1 ≤G M2 ≤GM3 (7)

[0139] Next, the battery cells within the subarrays of M are connected in parallel, while the subarrays are connected in series to form the basic array T0. This array is connected using a TCT structure.

[0140] 3. Since the basic array T0 obtained from the above steps is only an approximate optimal solution, array T0 must be optimized to minimize the difference in irradiance between the subarray with the strongest sum of irradiance intensity and the subarray with the weakest sum of irradiance intensity.

[0141] First, select the cell element T with the highest and lowest light intensity in T0. 0max ', T 0min (The light intensities at the corresponding structural boundary points are G) 0max and G 0min ), calculate the difference in light intensity ΔG under the condition of their boundary point. d .like:

[0142] G 0max =0.9T 0max (8)

[0143] G 0min =T 0min (9)

[0144] ΔG d =G 0min -G 0max (10)

[0145] If ΔG d If the value is greater than 0, then T0 is replaced by a new array T1, which is a conventional fully cascaded structure.

[0146] Secondly, take T 0max The battery element and T 0min Battery cell T with slightly stronger light intensity mid Comparison (the light intensities at the upper and lower boundary points of the corresponding structures are G respectively) 0max 'and G 0min '), calculate the difference in light intensity ΔG under the condition of their boundary point. d '.

[0147] Then, increase T sequentially. 0min Medium light intensity ratio T 0max Slightly weaker battery element T mid The light intensity difference ΔG between them is calculated based on the boundary point condition. imax ΔG imin (i: Irradiance is located at T) 0min With T 0max (between i battery cells)

[0148] ΔG imax =|T mid -1 / 0.9×T 0max | (11)

[0149] ΔG imin =T mid -0.9×T 0max (12)

[0150] G i =i×T mid (13)

[0151] Then, if there are a total of i battery cells, then ΔG satisfies... imin If the condition is greater than 0, then block T of type i will be... mid The battery cells are combined, and the sum of the irradiance is G. i T 0min The battery cells are connected in parallel to form a new subarray T. i If none of them satisfy G 0max >G i >G 0min If so, then a conventional parallel connection structure is selected.

[0152] The simulation results analysis in the next section, using i=2 battery cells as an example, provides a detailed explanation of the results of the improved TCT optimization and reconstruction algorithm. Furthermore, a comparative analysis of the output power of the electrical connection structure derived by this algorithm and other connection structures is presented.

[0153] 3. Optimal Electrical Connection Structure under Irradiation Uniformity Algorithm

[0154] In this invention, the laser cell array uses a composite TCT instead of a simple series-parallel wiring configuration, and its main structural features are:

[0155] Based on the irradiance uniformity algorithm, this study combines the advantages of TCT, series, and parallel structures. Using the TCT structure as the main component, other laser cells with lower irradiance are connected in series to increase the voltage at the maximum output power point. Finally, the two structures are combined in parallel. This allows cells with lower irradiance uniformity to achieve common output with high efficiency. The resulting optimal electrical connection structure not only has a maximum output power almost equal to that of a fully parallel connection structure, but also significantly improves the maximum output voltage.

[0156] The improved TCT configuration has three important features:

[0157] 1) The voltage of MPP is largely independent of irradiance, or in other words, even at different levels of irradiance uniformity, the MPP of the cells connected by this method occurs at almost the same common voltage.

[0158] 2) Slight deviations in MPP voltage will only have a minor effect on the generated power.

[0159] 3) The voltage of the MPP is relatively insensitive to temperature within a normal range. Therefore, regardless of the uniformity of the illumination distribution, the laser cell array with the improved TCT configuration enables each cell on the panel to simultaneously generate near-maximum power. Different cells in the panel can provide different currents corresponding to the irradiance level falling upon them. However, all cells share a common voltage and will be controlled to track the MPP.

[0160] The following example illustrates how to increase available power by changing the internal battery connection structure of the array. Figure 9 The diagram shows a TCT structure consisting of nine identical laser cell modules under different irradiance levels, corresponding to a static projection pattern (irradiance is highest in the center and decreases regularly around the edges).

[0161] This method can be applied in the early stages of design, specifically for designing the battery array based on the laser power. It can also be designed as a switching matrix. Figure 9 As can be seen, this is the sixth set of data in Table 1, with an irradiance of 1000 W / m. 2 543.84W / m 2 87.47W / m 2 The irradiation uniformity requirement is met: 0.9 × S1 > S2 > 0.9 S1. Figure 9 The sum of the irradiance for each row is 719.24 W / m. 2 2087.68W / m 2 719.24W / m 2 At this point, the main output comes from the intermediate battery, with a final output power of 664.7W / m. 2 Simulation results show that, based on the principle of uniform irradiance, the battery array can be arranged as follows: Figure 10 As shown, the output power increased from 664.7W to 1026W. At this point, the sum of the irradiance of each row in the internal TCT structure is 1000W / m. 2 1087.68W / m 2 1087.68W / m 2 To meet the requirements for irradiation uniformity, the output power of the subarrays was increased by 54.35% by using a series connection method.

[0162] The maximum output power under the non-irradiance uniformity algorithm is 664.7W, and the maximum output power under the irradiance uniformity algorithm is 1026W.

[0163] Furthermore, the assumption is that Figure 9The same static projection mode was considered, and the maximum available power was compared between different array configurations.

[0164] The results are reported in Table 4, where the improved TCT structure is the TCT configuration structure under the irradiation uniformity algorithm. Figure 10 ), fully series refers to a method where all laser cells are connected in series, fully parallel refers to a method where all laser cells are connected in parallel, and the TCT structure is the TCT configuration structure under the non-irradiance uniformity algorithm. Figure 9 ).

[0165] Table 4. Maximum output power of different laser cell array configurations in static projection mode.

[0166]

[0167] The sum of the output power of all individual cells in the array is 1052.7W. As shown in Table 4, the efficiency of the improved TCT structure is almost equal to that of the fully parallel connection structure. However, the improved TCT structure increases the maximum output point voltage to 165.6V, which is 213% higher than the maximum power point voltage of the fully parallel structure. Furthermore, the electrical connection method of the TCT structure changed significantly before and after optimization, indicating that the output characteristics of the array also changed accordingly. The output efficiency of the array improved by 34.3% after optimization. The simulation results are as follows... Figure 11 and Figure 12 As shown.

[0168] like Figure 11 As shown, the PU curve of the improved TCT structure is represented by the solid line, where the optimal characteristic curve is the most efficient. Compared with the TCT structure without irradiation uniformity algorithm, the efficiency is improved by 34.32%. In terms of output current at maximum power point, the output current of the improved TCT structure is 6.7A, which is 46.17A lower than that of the parallel structure.

[0169] 4. Comparison of output power of DC-DC topologies under equal voltage conditions

[0170] Table 4 shows that the fully parallel connection structure and the improved TCT structure have similar circuit efficiencies. However, in practical applications, the fully parallel connection structure is avoided as much as possible because its maximum power point output current is very large. When a load is present in the configuration, the circuit loss increases significantly. To clearly compare the circuit efficiencies of the fully parallel connection structure and the improved TCT connection structure, a laser wireless energy receiving system will be developed to compare the maximum power output of laser cell arrays with different structures at the same voltage level. Figure 13 As shown.

[0171] The developed laser wireless energy receiving system, such as Figure 13 As shown, there are three main characteristics:

[0172] 1) Compared with traditional multi-unit series, parallel or TCT structures, the laser cell array of the system described in this invention adopts an optimized TCT composite structure.

[0173] 2) MPPT is achieved by controlling the operating voltage of the laser cell array to conform to a specified voltage reference corresponding to MPP.

[0174] 3) Boost power converter, manages battery load and boosts voltage to system requirements.

[0175] 4.1 Input Voltage of Power Converter

[0176] In principle, it is best to connect all batteries in parallel. However, the terminal voltage of parallel-connected batteries is very low, which may increase the difficulty of designing a suitable power converter. At higher input voltages, the energy efficiency of the power converter improves, allowing the laser batteries to operate in parallel. As a trade-off, for laser batteries under Gaussian beams, the batteries receiving the main irradiation (a combination of batteries with similar irradiation) can be connected first in a TCT structure. For other laser batteries with lower irradiation intensities, a series connection is chosen to increase the voltage before parallel connection. If the size of the laser battery is smaller than the structural size of the illumination spot, it can generally be assumed that the entire area is under relatively uniform irradiation. If the irradiance at the outermost edge of the laser battery array is almost zero, then this is equivalent to the irradiance of the entire spot. Therefore, the results are consistent, and the laser wireless power system proposed in this invention is applicable regardless of the variation in laser spot coverage.

[0177] This invention employs and verifies this method, the details of which will be described in the next section. Two parallel photovoltaic panels were constructed in an improved TCT structure system, one consisting of five cells connected in series, and the other consisting of four cells connected in series. The results show that the power generated by the laser cell array configured in parallel with these two structures is significantly increased compared to a parallel configuration with the same number of cells and irradiance.

[0178] 4.2 Improve the performance of TCT configuration and parallel configuration

[0179] This invention connects different array connection structures with subsequent topologies, enabling the voltage levels of the two connection structures to reach 220V, and then compares their output power. Figure 14 As shown.

[0180] The battery array output is connected to an MPPT and a boost circuit. The MPPT circuit matches the internal resistance, allowing the battery array to output at its maximum power point. After boosting, the output voltage for both structures is 220V. Due to impedance losses in this topology, the output power is reduced.

[0181] like Figure 14 As shown, the fully parallel connection structure, represented by the blue dashed line, exhibits significant waveform jitter, with a stable output power of approximately 252W. At this point, the boost circuit efficiency of this structure is 0.8108. In contrast, the improved TCT structure, represented by the red solid line, achieves an output power of around 565W, with a boost circuit efficiency of 0.9779. Comparing the two, the improved TCT structure's output power is 2.24 times that of the fully parallel connection structure. This indicates that in practical applications, the efficiency of the fully parallel connection structure will decrease due to load considerations, and the improved TCT structure should be prioritized.

[0182] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for designing an array structure with optimized output power at the efficiency threshold, characterized in that: The method includes the following steps: S1: Output design of series-parallel components under uneven irradiation; specifically including: S11: Output design of a series-parallel assembly of two batteries under uneven irradiation; Define the circuit efficiency of the battery assembly The ratio of the maximum output power of the module under non-uniform illumination conditions to the sum of the maximum output power of all laser cells in the battery module is shown in equation (1): （1） In the formula: This represents the maximum power output of the battery module under uneven irradiation conditions. For the first i Maximum output power of the block laser cell; N The number of laser cells; Received irradiance and The ratio of received light intensity measures the uniformity of light intensity distribution. ; When the uniformity of illumination is approximately 0.4, the power loss is greatest and the circuit efficiency is lowest at 68.62% in the series configuration; when the uniformity is 0, the illumination uniformity is poor, and in the series configuration, only the circuit with the highest irradiance receives power. Output power to the outside Loss efficiency; when The stronger the received radiation, the greater the power consumption, and the lower the efficiency of the component circuit; in the middle section, the uniformity of illumination improves. and Simultaneously outputting power; the greater the uniformity of illumination. The further the circuit deviates from the maximum power point, the greater the power loss and the lower the circuit efficiency; finally, and The higher the uniformity of the received light intensity, the closer the laser cell is to its maximum power point, and the higher the circuit efficiency. Under uniform irradiation, there is no loss, and the circuit efficiency is up to 100%. When the uniformity is 0 or 1, the circuit efficiency of the series component intersects with that of the parallel component. S12: Analysis of the Relationship between Series-Parallel Components of Multiple Batteries and Light Spot Coverage under Non-uniform Irradiation Gaussian laser irradiation is characterized by strong irradiation in the center and weak irradiation around the edges, exhibiting the following pattern: （2） （3） in The ratio of the energy of the beam emitted through the beam pointer. The energy ratio of a beam emitted vertically through the atmosphere. The angle between the beam and the vertical axis. For the entire laser energy, The beam quality coefficient. For the Strehl ratio, The wavelength for emitting laser light; The aperture of the launching telescope; Set the center position to 1000W / m 2 The laser power formula is derived to determine the irradiation distance. The irradiance of each cell is obtained by setting its receiving area. Calculations are performed on three cells. When the irradiance of the cells at the edge is approximately zero, the coverage rate is defined as 100%, based on the receiving area. Under Gaussian distribution and with no load, considering the cell internal resistance and protection diode consumption, the beam coverage rate is calculated using the receiving area. Light spot coverage The values ​​range from 1 to 0, and are divided into 12 groups. The radiation intensity of the three batteries is calculated using formula (2). The three batteries are connected in parallel and the output power is measured. When the spot coverage is equal to 1, the Gaussian irradiance on the laser battery is respectively , and When connected in parallel, the total output power is 319.4W, and the maximum power point voltage is... At this time, the output power of a single battery is as follows: , and ; the corresponding maximum power point voltage , and Calculate the circuit efficiency according to equation (1). The circuit efficiency is 97.43%. The maximum output power increases with increasing irradiance intensity; when the irradiance intensity is greater than 677.18 W / m², the maximum output power increases. 2 When the maximum power point voltage changes less, a series connection is selected; when the maximum power point voltage is close, multiple batteries are connected in series to output power together; the maximum output power of a single battery at different irradiation intensities is applicable to both series and parallel circuit efficiency calculations. Light spot coverage From 0 to 1, when the light spot coverage When the irradiance is equal to 0, the three batteries receive the same irradiance, and the uniformity is... Maximum value is 1; edge uniformity Defined as the ratio of the battery with the lowest irradiance to the battery with the highest irradiance among the three batteries, the formula is as follows: （4） In formula (4) For an irradiation intensity of 1000 W / m 2 The first battery below, It is the battery with the lowest radiation intensity among the three batteries; When the light spot coverage is greater than 0.1, the efficiency of the series circuit is significantly lower than that of the parallel circuit; when the light spot coverage is equal to 0.1, the efficiency of the series connection structure circuit exceeds that of the parallel connection structure for the first time, at which point the edge uniformity... Equal to 0.9; When three batteries receive Gaussian-distributed irradiation, if the irradiation uniformity is above 0.9, the circuit efficiency of the series connection structure is greater than that of the parallel connection structure. When there is a combination of three batteries, and the edge irradiance uniformity is above 0.9 or the spot coverage is less than 0.1, the series connection structure can improve the circuit efficiency. When applied to the laser wireless energy transmission system of 3×3 laser battery array in static scene, the corresponding optimal electrical connection structure is found for different uniformities. S2: Establish an algorithm for the uniformity of irradiation of a static 3×3 laser cell array; specifically including: The electrical layout of the 3×3 laser cell array is analyzed, and the specific process is as follows: S21: Input spot diameter ; S22: Input laser battery length ,Width The following research is x = y The situation; S23: Taking the center of the light spot as the origin, let the horizontal coordinate of the battery at the center position be... y-axis The horizontal coordinate of the battery at the same power position in the second category y-axis The horizontal coordinate of the third type of battery with the same power position y-axis ; S24: Distance from the center of the light spot: , , ; S25: Set the power at the center point of the light spot to... The power value is located at the center of the light spot; , Substituting into the simplified formula for laser power, the calculation is obtained. , ; 3 In the 3-dimensional TCT laser cell array structure, (0, 0) is the origin of the coordinate system. x The x-axis is... y The vertical axis is used as the coordinate. The battery is located at the corresponding coordinates. x = y And the center of the laser irradiation spot is located The laser cell array only has three power levels. , , ; In the aforementioned TCT laser cell array structure, when the photovoltaic array of the TCT structure is optimized under Gaussian laser irradiation, the number of subarrays in the array remains unchanged before and after optimization, but the number of photovoltaic cells connected in parallel in different subarrays is inconsistent. The quality of the electrical connection method of the TCT structure is judged by comparing the difference in irradiance between the two subarrays with the largest and smallest sum of irradiance intensity. The smaller the difference in irradiance, the better the uniformity of irradiance received by each subarray in the structure, and the better the electrical connection method. The specific process for finding the optimal electrical connection structure for different uniformities in the laser wireless energy transmission system of the 3×3 laser battery array in a static scene is as follows: S121: Determine the irradiance of individual cells in the array , , And sort; By inputting the beam diameter, the length and width of the laser cell, and the power at the center of the beam, the irradiance of each cell in the array can be calculated. , , The laser cells were arranged in sequence according to the light intensity received, from highest to lowest. A ,like: (5) (6) 3 The TCT structure of the 3-cell laser array has three subarrays, each composed of cells with equal irradiance. To ensure that the sum of irradiance received by each subarray is as equal as possible, the sum of irradiance received by each subarray is first calculated and then arranged in ascending order to form a subarray sequence. M ,like (7) Secondly, in sequence M The battery cells within the subarrays are connected in parallel, while the subarrays are connected in series to form the basic array. The array is connected using a TCT structure. choose The battery cells with the highest and lowest light intensity , The light intensities at the corresponding structural boundary points are respectively and Calculate the difference in light intensity under the condition of their boundary point. ;like: (8) (9) (10) like If the value is greater than 0, then use the new array. replace ; Pick Battery components and Battery cells with slightly stronger light intensity The light intensities at the upper and lower boundary points of the corresponding structures were compared. and Calculate the difference in light intensity under the condition of their boundary point. ; Increase sequentially Medium light ratio Slightly weaker battery element The light intensity difference between them is calculated based on the boundary point condition. ， Indicates that the irradiance is located at and Between Block battery unit; (11) (12) (13) If there is a total i When the battery is in use, it meets the requirements. The conditions will then i piece The battery cells are combined, and the sum of the irradiance is... , The battery cells are connected in parallel to form a new subarray. If none of these conditions are met ; The battery array output is connected to the MPPT and boost circuit. The MPPT circuit can match the internal resistance to make the battery array operate at maximum power. S3: Establish the optimal electrical connection structure under the irradiance uniformity algorithm.

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