A design method for an offshore floating photovoltaic system and a floating photovoltaic system

Abstract

The present invention discloses a design method for an offshore floating photovoltaic system and a floating photovoltaic system, and relates to the field of photovoltaic power generation technology. The method determines the component number range of photovoltaic components in each photovoltaic string according to the target temperature of the set sea area, the first electrical data of the photovoltaic component, and the second electrical data of the inverter. And according to the wavelength of the waves in the set sea area, the array side length range of each photovoltaic array is determined, and then the target component number corresponding to each photovoltaic string and the number of photovoltaic strings corresponding to each photovoltaic array are screened out in combination with the component number range, the array side length range, and the component size of the photovoltaic component. According to the target component number and the number of photovoltaic strings, the size and number of floating bodies carrying each photovoltaic array are determined, and each floating body is fastened by a cable and at least one photovoltaic component is fully installed. By optimizing the system performance in multiple dimensions, the service life and operational stability of the photovoltaic system in the set sea area can be guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to a design method for an offshore floating photovoltaic system and a floating photovoltaic system. Background Art

[0002] In recent years, photovoltaic power generation has developed rapidly as a renewable energy source. Among them, water photovoltaic power generation is more popular among the public because it does not occupy too much land resources and is eco-friendly.

[0003] However, with the large-scale development of water photovoltaic power generation, when the water photovoltaic power generation system is applied to offshore power generation, the differences between the photovoltaic power generation systems used in the sea area and in closed waters are not fully taken into account, which greatly shortens the service life of the photovoltaic power generation system in the sea area. Summary of the invention

[0004] In view of the above problems, the present invention is proposed to provide a design method for an offshore floating photovoltaic system and a floating photovoltaic system that overcome the above problems or at least partially solve the above problems.

[0005] According to a first aspect of the present invention, the present invention provides a design method for an offshore floating photovoltaic system, wherein the photovoltaic system comprises at least one photovoltaic array with a square cross section and a plurality of floating bodies carrying the photovoltaic array, wherein the photovoltaic array comprises a plurality of photovoltaic strings and inverters coupled to the photovoltaic strings, wherein each photovoltaic string is composed of a plurality of photovoltaic components connected in series in the same direction, wherein the number of photovoltaic components in each photovoltaic string is the same;

[0006] The design method comprises:

[0007] Determining the range of the number of photovoltaic components in each photovoltaic string according to the target temperature of a set sea area, the first electrical data of the photovoltaic components and the second electrical data of the inverter, wherein the set sea area is the sea area where the photovoltaic system is to be placed;

[0008] Determining the range of the array side length of each photovoltaic array according to the wavelength of the waves in the set sea area;

[0009] According to the component quantity range, array side length range and component size of the photovoltaic components, the target component quantity corresponding to each photovoltaic string and the photovoltaic string quantity corresponding to each photovoltaic array are screened out;

[0010] The size and number of floats carrying each photovoltaic array are determined according to the target number of components and the number of photovoltaic strings, wherein the floats are fastened by cables and each of them is fully equipped with at least one photovoltaic component.

[0011] Optionally, determining the range of the number of photovoltaic components in each photovoltaic string according to the target temperature of the set sea area, the first electrical data of the photovoltaic components, and the second electrical data of the inverter includes:

[0012] According to the target temperature of the set sea area and the first electrical data of the photovoltaic module, the maximum open circuit voltage and the maximum operating voltage of each photovoltaic module at the target temperature are determined;

[0013] Determining a first component quantity value of photovoltaic components corresponding to each photovoltaic string according to the second electrical data and the maximum open circuit voltage of the inverter;

[0014] Determine a second component quantity value and a third component quantity value of photovoltaic components corresponding to each photovoltaic string according to the second electrical data and the maximum operating voltage of the inverter, wherein the third component quantity value is less than the second component quantity value and less than the first component quantity value;

[0015] The third component quantity value is used as the component quantity lower limit value of the photovoltaic components in each photovoltaic string, and the component quantity upper limit value of the photovoltaic components in each photovoltaic string is determined according to the first component quantity value and the second component quantity value, so as to generate a corresponding component quantity range.

[0016] Optionally, determining the maximum open circuit voltage of each photovoltaic module at the target temperature according to the target temperature of the set sea area and the first electrical data of the photovoltaic module includes:

[0017] Determine the temperature difference between the target temperature of the set sea area and the test condition temperature corresponding to the photovoltaic module;

[0018] A first weighting operation is performed on the temperature difference using the open circuit temperature coefficient of the photovoltaic module, and a maximum open circuit voltage of each photovoltaic module at a target temperature is calculated based on the weighted temperature difference and the open circuit voltage of each photovoltaic module.

[0019] Optionally, determining the maximum operating voltage of each photovoltaic module at the target temperature according to the target temperature of the set sea area and the first electrical data of the photovoltaic module includes:

[0020] A second weighted operation is performed on the temperature difference using the operating temperature coefficient of the photovoltaic module, and a maximum operating voltage of each photovoltaic module at a target temperature is calculated based on the weighted temperature difference and the operating voltage of each photovoltaic module.

[0021] Optionally, determining a first component quantity value of photovoltaic components corresponding to each photovoltaic string according to the second electrical data and the maximum open-circuit voltage of the inverter includes:

[0022] According to the maximum open circuit voltage of the photovoltaic component at the target temperature, the maximum number of photovoltaic component blocks corresponding to each photovoltaic string when the open circuit voltage of the string is less than or equal to the maximum input voltage of the DC side of the inverter is calculated and used as the first component quantity value.

[0023] Optionally, determining the second component quantity value of the photovoltaic components corresponding to each photovoltaic string according to the second electrical data and the maximum operating voltage of the inverter includes:

[0024] According to the maximum operating voltage of the photovoltaic component at the target temperature, the maximum number of photovoltaic component blocks corresponding to each photovoltaic string when the string operating voltage is less than or equal to the maximum value of the inverter MPPT (Maximum Power Point Tracking) voltage is calculated and used as the second component quantity value.

[0025] Optionally, determining a third component quantity value of photovoltaic components corresponding to each photovoltaic string according to the second electrical data and the maximum operating voltage of the inverter includes:

[0026] According to the maximum operating voltage of the photovoltaic component at the target temperature, the maximum number of photovoltaic component blocks corresponding to each photovoltaic string when the string operating voltage is greater than or equal to the minimum value of the inverter MPPT voltage is calculated and used as the third component quantity value.

[0027] Optionally, determining the array side length range of each photovoltaic array according to the wavelength of waves in the set sea area includes:

[0028] One sixth of the wavelength of the sea waves in the set sea area is determined as the minimum value of the array side length of each photovoltaic array;

[0029] One quarter of the wave length of the ocean wave is determined as the maximum value of the array side length of each photovoltaic array;

[0030] The array side length range of each photovoltaic array is determined according to the minimum value and the maximum value of the array side length.

[0031] Optionally, the method further includes:

[0032] When the directions of the photovoltaic components in multiple photovoltaic strings are inconsistent, the output end of each photovoltaic string is coupled to a power optimizer.

[0033] According to a second aspect of the present invention, the present invention provides a floating photovoltaic system, which is manufactured according to any of the above-mentioned design methods.

[0034] Compared with the prior art, the present invention determines the range of the number of photovoltaic modules in each photovoltaic string according to the target temperature of the set sea area, the first electrical data of the photovoltaic module and the second electrical data of the inverter, and sets the sea area as the sea area where the photovoltaic system is to be placed. According to the wavelength of the waves in the set sea area, the range of the array side length of each photovoltaic array is determined, and then the target number of modules corresponding to each photovoltaic string and the number of photovoltaic strings corresponding to each photovoltaic array are screened out in combination with the range of the number of modules, the range of the array side length and the size of the photovoltaic modules. Finally, according to the target number of modules and the number of photovoltaic strings, the size and number of floats carrying each photovoltaic array are determined, and each float is fastened by a cable and at least one photovoltaic module is fully installed. The present application not only takes into account the impact on the electrical performance of the photovoltaic modules, but also takes into account the impact of the wavelength of the waves on the photovoltaic array, thereby optimizing the performance of the offshore floating photovoltaic system through multiple dimensions, and can ensure the service life and operational stability of the photovoltaic system in the set sea area.

[0035] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limitations of the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings.

[0037] In the attached picture:

[0038] Figure 1 It is a schematic diagram of the steps of a design method of an offshore floating photovoltaic system provided by an embodiment of the present invention;

[0039] Figure 2 is a schematic diagram of the steps of another design method of an offshore floating photovoltaic system provided by an embodiment of the present invention;

[0040] Figure 3 is a schematic diagram of the position state of a photovoltaic array in the waves provided by an embodiment of the present invention;

[0041] Figure 4 It is a structural schematic diagram of a floating body provided by an embodiment of the present invention;

[0042] Figure 5 It is a structural schematic diagram of a floating photovoltaic system provided by an embodiment of the present invention.

[0043] Reference numerals: 1. photovoltaic array; 101. photovoltaic module; 2. combiner; 3. inverter; 4. floating body. DETAILED DESCRIPTION

[0044] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0045] Reference Figure 1 , shows a design method of an offshore floating photovoltaic system, the photovoltaic system includes at least one photovoltaic array 1 with a square cross-section and a plurality of floating bodies 4 carrying the photovoltaic array 1, the photovoltaic array 1 includes multiple photovoltaic strings and inverters 3 coupled to each photovoltaic string, each photovoltaic string is composed of multiple photovoltaic components 101 connected in series in the same direction, wherein the number of photovoltaic components 101 in each photovoltaic string is the same. The design method may include:

[0046] S101, determining a component quantity range of photovoltaic components in each photovoltaic string according to a set target temperature of the sea area, first electrical data of the photovoltaic components, and second electrical data of the inverter.

[0047] In the embodiment of the present invention, the set sea area is the sea area where the photovoltaic system is to be placed, wherein the target temperature may be the lowest temperature corresponding to the set sea area within one year, or the temperature average of the lowest temperature corresponding to each month within 12 months, etc. The first electrical data of the photovoltaic module 101 may be the relevant electrical data obtained by testing the photovoltaic module 101 under the standard test condition temperature (i.e., 25°C), and the first electrical data may include the open circuit voltage, working voltage, open circuit temperature coefficient, working temperature coefficient and other data of the photovoltaic module 101. Among them, the open circuit temperature coefficient refers to the percentage of increase or decrease of the corresponding open circuit voltage when the temperature increases or decreases by one degree. The working temperature coefficient refers to the percentage of increase or decrease of the corresponding working voltage when the temperature increases or decreases by one degree. The second electrical data of the inverter 3 may include the input maximum voltage of the DC side of the inverter 3, the minimum value of the MPPT voltage of the inverter 3, and the maximum value of the MPPT voltage of the inverter 3. Therefore, the target temperature of the set sea area can be fully considered, and the component quantity range of the photovoltaic components 101 in each photovoltaic string can be determined by combining the first electrical data of the photovoltaic components 101 and the second electrical data of the inverter 3, so as to avoid the system being frequently damaged by the temperature of the set sea area during operation, thereby affecting the power generation efficiency.

[0048] S102: Determine the range of the array side length of each photovoltaic array according to the wavelength of the waves in the set sea area.

[0049] In the embodiment of the present invention, since the photovoltaic array 1 floats in the set sea area through the floating body 4, when there are waves in the sea area, the waves will impact the photovoltaic array 1 and affect the structural stability of the photovoltaic array 1. Therefore, by combining the wavelength of the waves in the set sea area to determine the array side length range of each photovoltaic array 1, the structural stability of the photovoltaic array 1 can be improved, and the service life of the system can be effectively extended.

[0050] S103, screening out the target number of components corresponding to each photovoltaic string and the number of photovoltaic strings corresponding to each photovoltaic array according to the component number range, array side length range and component size of the photovoltaic components.

[0051] In the embodiment of the present invention, the predicted number within the range of the array side length is determined by the component size of the photovoltaic component 101, and a predicted number within the component number range is selected as the target component number corresponding to each photovoltaic string. Finally, the number of photovoltaic strings corresponding to each photovoltaic array 1 is determined based on the component size.

[0052] S104, determining the size and number of floats that carry each photovoltaic array according to the target number of modules and the number of photovoltaic strings, wherein the floats are fastened to each other by cables and each has at least one photovoltaic module completely installed thereon.

[0053] In the embodiment of the present invention, at least one photovoltaic module 101 can be completely installed on each floating body 4, wherein the complete installation can be understood as that during the installation process, each photovoltaic module 101 does not need to be installed across the floating body 4. Therefore, the floating body size of each floating body 4 is respectively adapted to the component size of at least one photovoltaic module 101, and according to this adaptation relationship, the target component number and the number of photovoltaic strings of the photovoltaic array 1, the floating body size and the number of floating bodies can be determined, so that all the floating bodies 4 in the photovoltaic system are fully installed with photovoltaic modules 101, and no installation position of a photovoltaic module 101 is reserved, thereby realizing the regular arrangement between each photovoltaic module 101 and the floating body 4 in the photovoltaic system.

[0054] The above design method not only takes into account the impact on the electrical performance of the photovoltaic module 101, but also takes into account the impact of the wavelength of the waves on the photovoltaic array 1, thereby optimizing the performance of the offshore floating photovoltaic system through multiple dimensions, and can ensure the service life and operational stability of the photovoltaic system in the set sea area.

[0055] Reference Figure 2 , another design method of an offshore floating photovoltaic system is shown, the design method may include:

[0056] Determining the component quantity range of the photovoltaic components 101 in each photovoltaic string according to the target temperature of the set sea area, the first electrical data of the photovoltaic components 101 and the second electrical data of the inverter 3 includes the following steps: steps S201-S204.

[0057] The set sea area is the sea area where the photovoltaic system is to be placed. Among them, the target temperature can be the lowest temperature corresponding to the set sea area within one year, or the temperature average of the lowest temperature corresponding to each month within 12 months. The first electrical data of the photovoltaic module 101 can be the relevant electrical data obtained by testing the photovoltaic module 101 under the standard test condition temperature (i.e., 25°C), and the first electrical data can include the open circuit voltage, working voltage, open circuit temperature coefficient, working temperature coefficient and other data of the photovoltaic module 101. The second electrical data of the inverter 3 can include the input maximum voltage of the DC side of the inverter 3, the minimum value of the MPPT voltage of the inverter 3, and the maximum value of the MPPT voltage of the inverter 3. In this way, the target temperature of the set sea area can be fully considered, and the first electrical data of the photovoltaic module 101 and the second electrical data of the inverter 3 can be combined to determine the range of the number of components of the photovoltaic module 101 in each photovoltaic string, so as to avoid the system being frequently damaged by the temperature of the set sea area during operation, thereby affecting the power generation efficiency.

[0058] S201. Determine the maximum open circuit voltage and the maximum operating voltage of each photovoltaic module at the target temperature according to the target temperature of the set sea area and the first electrical data of the photovoltaic module.

[0059] In the embodiment of the present invention, the temperature difference between the target temperature of the set sea area and the test condition temperature corresponding to the photovoltaic module 101 is first determined. For example, when the target temperature of the set sea area is -20°C, the corresponding temperature difference is -45°C. A first weighted operation is performed on the temperature difference through the open circuit temperature coefficient of the photovoltaic module 101. The open circuit temperature coefficient refers to the percentage of increase or decrease of the corresponding open circuit voltage for each degree increase or decrease in temperature. If the open circuit temperature coefficient is a negative value, it means that the corresponding open circuit voltage decreases by a corresponding percentage for each degree increase in temperature. The first weighted operation can be to multiply the open circuit temperature coefficient by the temperature difference and add 1. For example, when the open circuit temperature coefficient is -0.3%, the temperature difference after the first weighted operation is 0.135. Then, based on the weighted temperature difference and the open circuit voltage of each photovoltaic module 101, the maximum open circuit voltage of each photovoltaic module 101 at the target temperature is calculated. Therefore, the maximum open circuit voltage Vk of each photovoltaic module 101 at the target temperature can be calculated by the following formula (1):

[0060] Vk=Voc*[1+(t-25)*Kv] Formula (1)

[0061] In the above formula (1), Voc is the open circuit voltage of the photovoltaic module 101 under the test condition temperature; t is the target temperature, and Kv is the open circuit temperature coefficient.

[0062] By analogy with the above determination of the maximum operating voltage of each photovoltaic module 101 at the target temperature, the operating temperature coefficient refers to the percentage of increase or decrease in the corresponding operating voltage for each degree increase or decrease in temperature. If the operating temperature coefficient is a negative value, it means that the corresponding operating voltage decreases by a corresponding percentage for each degree increase in temperature. A second weighted operation is performed on the temperature difference using the operating temperature coefficient of the photovoltaic module 101. The second weighted operation may be to multiply the operating temperature coefficient by the temperature difference and add 1. For example, when the operating temperature coefficient is -0.2%, the temperature difference after the first weighted operation is 0.09. Based on the weighted temperature difference and the operating voltage of each photovoltaic module 101, the maximum operating voltage of each photovoltaic module 101 at the target temperature is calculated. Therefore, the maximum operating voltage Vg of each photovoltaic module 101 at the target temperature can be calculated using the following formula (1):

[0063] Vg=Vpm*[1+(t-25)*Ks] Formula (2)

[0064] In the above formula (2), Vpm is the operating voltage of the photovoltaic module 101 under the test condition temperature; t is the target temperature, and Ks is the operating temperature coefficient.

[0065] S202: Determine a first component quantity value of photovoltaic components corresponding to each photovoltaic string according to the second electrical data and the maximum open-circuit voltage of the inverter.

[0066] In the embodiment of the present invention, the voltage input from each photovoltaic string to the DC side of the inverter 3 is the sum of the output voltages corresponding to all photovoltaic modules 101 in each photovoltaic string. In order to ensure the operational stability of the system, the total output open-circuit voltage of each photovoltaic string (i.e., the open-circuit voltage of the group string) needs to be less than or equal to the maximum input voltage of the DC side of the inverter 3. Therefore, the maximum number of photovoltaic modules 101 corresponding to each photovoltaic string when the open-circuit voltage of the group string is less than or equal to the maximum input voltage of the DC side of the inverter 3 can be calculated based on the maximum open-circuit voltage of the photovoltaic module 101 at the target temperature, and used as the first module quantity value. Among them, the first module quantity value N1 can be calculated by the following formula (3):

[0067]

[0068] In the above formula (3), Vdcmax is the maximum input voltage of the DC side of the inverter 3. For example, the first component quantity value N1 is calculated to be 24.

[0069] S203: Determine a second component quantity value and a third component quantity value of photovoltaic components corresponding to each photovoltaic string according to the second electrical data and the maximum operating voltage of the inverter.

[0070] In an embodiment of the present invention, in order to ensure the operational stability of the system, the total operating voltage of each photovoltaic string (i.e., the string operating voltage) needs to be less than or equal to the maximum value of the inverter 3MPPT voltage, and needs to be greater than or equal to the minimum value of the inverter 3MPPT voltage. Wherein, the inverter 3MPPT voltage refers to the operating voltage of the MPPT controller in the inverter 3. Therefore, based on the maximum operating voltage of the photovoltaic module 101 at the target temperature, the maximum number of photovoltaic modules 101 corresponding to each photovoltaic string can be calculated under the condition that it is less than or equal to the maximum value of the inverter 3MPPT voltage, and used as the second module quantity value, where the second module quantity value N2 can be calculated by the following formula (4):

[0071]

[0072] In the above formula (4), Vmpptmax is the maximum value of the inverter 3MPPT voltage. By dividing the maximum value of the inverter 3MPPT voltage by the maximum operating voltage Vg of each photovoltaic module 101 at the target temperature, and rounding down the obtained quotient, the maximum number of photovoltaic modules 101 corresponding to each photovoltaic string is obtained when it is less than or equal to the maximum value of the inverter 3MPPT voltage. For example, the second module quantity value N2 is calculated to be 27.

[0073] By analogy, the maximum number of photovoltaic modules 101 corresponding to each photovoltaic string when the string operating voltage is greater than or equal to the minimum value of the inverter 3MPPT voltage can be calculated based on the maximum operating voltage of the photovoltaic module 101 at the target temperature, and used as the third module quantity value, wherein the third module quantity value N3 can be calculated by the following formula (5):

[0074]

[0075] In the above formula (5), Vmpptmin is the minimum value of the inverter 3MPPT voltage. By dividing the minimum value of the inverter 3MPPT voltage by the maximum operating voltage Vg of each photovoltaic module 101 at the target temperature, and rounding up the obtained quotient, the maximum number of photovoltaic modules 101 corresponding to each photovoltaic string is obtained when the minimum value of the inverter 3MPPT voltage is greater than or equal to the minimum value of the inverter 3MPPT voltage. Therefore, the third number of components is less than the second number of components, and less than the first number of components. For example, the third number of components N3 is calculated to be 28.

[0076] S204: Using the third component quantity value as the lower limit value of the component quantity of photovoltaic components in each photovoltaic string, and determining the upper limit value of the component quantity of photovoltaic components in each photovoltaic string according to the first component quantity value and the second component quantity value, to generate a corresponding component quantity range.

[0077] In an embodiment of the present invention, the smaller value of the first component quantity value and the second component quantity value can be used as the upper limit value of the component quantity of the photovoltaic components 101 in each photovoltaic string, and the corresponding component quantity range is generated according to the smaller value of the third component quantity value, the first component quantity value, and the second component quantity value. In another example, a quantity range can be generated according to the third component quantity value and the first component quantity value, and another quantity range can be generated according to the third component quantity value and the second component quantity value. Take the intersection of the two quantity ranges, and generate the corresponding component quantity range according to the upper limit value corresponding to the intersection and the first component quantity value. For example, based on the above-determined first component quantity value N1 is 24, the second component quantity value N2 is 27, and the third component quantity value N3 is 28. The corresponding component quantity range is 24-27 blocks.

[0078] S205: Determine the range of the array side length of each photovoltaic array according to the wavelength of the waves in the set sea area.

[0079] In the embodiment of the present invention, since the photovoltaic array 1 floats in the set sea area through the floating body 4, when there are waves in the sea area, the waves will impact the photovoltaic array 1 and affect the structural stability of the photovoltaic array 1. Therefore, by combining the wavelength of the waves in the set sea area to determine the array side length range of each photovoltaic array 1, the structural stability of the photovoltaic array 1 can be improved, and the service life of the system can be effectively extended. Among them, the wave wavelength is the stable wave wavelength corresponding to the set sea area, which can be taken as the average of the wave wavelengths in the set sea area within one day.

[0080] Reference Figure 3 As shown, the position states of photovoltaic arrays 1 with different array side lengths in the waves are shown:

[0081] When the array side length corresponding to the photovoltaic array 1A is half of the wavelength of the sea wave, the photovoltaic array 1 will be driven by the sea wave, and a part of the photovoltaic array 1 will be suspended. For example, the photovoltaic array 1 on the wave crest will be suspended at both ends, and the photovoltaic array 1 in the middle part will support the entire photovoltaic array 1; the photovoltaic array 1 on the wave trough will be supported at both ends, and the middle part will be completely suspended. Moreover, the suspended part of the photovoltaic array 1 accounts for a large proportion, which makes the interior of the photovoltaic array 1 (such as the junction of the suspended part and the supporting part) produce a lot of stress for a long time, which easily leads to a decrease in the structural stability of the photovoltaic array 1 and greatly reduces the service life of the photovoltaic system.

[0082] When the array side length corresponding to the photovoltaic array 1B is one-fourth of the wavelength of the waves, the suspension phenomenon corresponding to the photovoltaic array 1 will be greatly reduced, and the suspended portion of the photovoltaic array 1 accounts for a small proportion, thereby reducing the stress generated in the photovoltaic array 1, which is beneficial to the long-term stability of the structure of the photovoltaic array 1.

[0083] When the array side length corresponding to the photovoltaic array 1C is one sixth of the wavelength of the waves, the photovoltaic array 1 will basically not be suspended. However, since the array side length is too short, the photovoltaic array 1 may be overturned or overlapped under the impact of the waves.

[0084] Therefore, according to the above analysis, one sixth of the wavelength of the waves in the set sea area can be determined as the minimum value of the array side length of each photovoltaic array 1. One quarter of the wavelength of the waves can be determined as the maximum value of the array side length of each photovoltaic array 1. According to the minimum and maximum values ​​of the array side length, the array side length range of each photovoltaic array 1 is determined. For example, when the wavelength of the waves in the set sea area is 240 meters, the array side length range of each photovoltaic array 1 is 40-60m. Among them, the array side length of the photovoltaic array 1 includes 40m and 60m.

[0085] S206 , based on the component quantity range, array side length range, and component size of the photovoltaic component 101 , screen out the target component quantity corresponding to each photovoltaic string and the photovoltaic string quantity corresponding to each photovoltaic array 1 .

[0086] In the embodiment of the present invention, the predicted number within the range of the array side length is determined by the component size of the photovoltaic component 101. The component size corresponding to the photovoltaic component 101 is generally a standard value, for example, the component size is 2*1m, and when the array side length range is 40-60m, if the component string is formed according to the width of the photovoltaic component 101, the corresponding predicted number is 40-60 pieces; if the component string is formed according to the length of the photovoltaic component 101, the corresponding predicted number is 20-30 pieces.

[0087] A predicted number included in the range of the number of components is screened out as the target number of components corresponding to each photovoltaic string. Among them, the range of the number of components is 24-27 blocks, and the predicted numbers included in the range of the number of components are determined to be 24 blocks, 25 blocks, 26 blocks and 27 blocks. Therefore, one of the at least one predicted number included in the range of the number of components can be screened out as the target number of components for each photovoltaic string. After determining the target number of components, the number of photovoltaic strings corresponding to each photovoltaic array 1 can also be determined based on the size of the components. For example, when the target number of components is 24, the side length of the corresponding photovoltaic array 1 is 48m, and the number of photovoltaic strings corresponding to each photovoltaic array 1 is determined to be 48.

[0088] S207. Determine the size and number of floats that carry each photovoltaic array according to the target number of components and the number of photovoltaic strings, wherein the floats are fastened to each other by cables and each has at least one photovoltaic component completely installed thereon.

[0089] In the embodiment of the present invention, at least one photovoltaic module 101 can be completely installed on each floating body 4, wherein the complete installation can be understood as that during the installation process, each photovoltaic module 101 does not need to be installed across the floating body 4. Therefore, the floating body size of each floating body 4 is respectively adapted to the component size of at least one photovoltaic module 101. According to this adaptation relationship, the target component number and the number of photovoltaic strings of the photovoltaic array 1, the floating body size and the number of floating bodies can be determined so that all the floating bodies 4 in the photovoltaic system are fully installed with photovoltaic modules 101, and no installation position of a photovoltaic module 101 is reserved, thereby realizing the regular arrangement between each photovoltaic module 101 and the floating body 4 in the photovoltaic system. For example, when the target component number is 24, the corresponding photovoltaic array 1 has a side length of 48m, and the corresponding floating body size can be 2*1m, 4*1m, 2*2m, etc., which is not limited here, so that the number of floating bodies carrying each photovoltaic array 1 is determined according to the floating body size. For example, when the size of the floating body is determined to be 2*2m (i.e., two photovoltaic modules 101 are installed on each floating body 4), the corresponding number of floating bodies is 576. The floating bodies 4 are fastened by cables. Thus, the structural stability of the system is further improved by improving the compactness and structural symmetry of the photovoltaic array 1.

[0090] In an optional embodiment of the invention, the method may further include:

[0091] When the orientations of the photovoltaic components 101 in multiple photovoltaic strings are inconsistent, the output end of each photovoltaic string is coupled to a power optimizer. Figure 4As shown, the upper surface of the float 4 provides fixed support for the photovoltaic assembly 101, wherein the photovoltaic assembly 101 on the same float 4 can have different inclination angles, for example, one facing west and the other facing east. Because the angles of absorbing solar radiation are different, there is a situation where the voltage is the same but the current is different, so the power optimizer is used to solve the current mismatch problem between photovoltaic strings in different directions. After being processed by the power optimizer, each photovoltaic string is coupled to the concentrator 2 and input to the DC side of the inverter 3 through a cable.

[0092] In summary, the present invention discloses a design method for an offshore floating photovoltaic system. According to the target temperature of the set sea area, the first electrical data of the photovoltaic module 101 and the second electrical data of the inverter 3, the component number range of the photovoltaic module 101 in each photovoltaic string is determined, and the sea area is set as the sea area where the photovoltaic system is to be placed. According to the wavelength of the waves in the set sea area, the array side length range of each photovoltaic array 1 is determined, and then the target number of components corresponding to each photovoltaic string and the number of photovoltaic strings corresponding to each photovoltaic array 1 are screened out in combination with the component number range, the array side length range and the component size of the photovoltaic module 101. Finally, according to the target number of components and the number of photovoltaic strings, the size and number of floating bodies carrying each photovoltaic array 1 are determined, and each floating body 4 is fastened by a cable and at least one photovoltaic module 101 is fully installed. The present application not only takes into account the impact on the electrical performance of the photovoltaic module 101, but also takes into account the impact of the wavelength of the waves on the photovoltaic array 1, thereby optimizing the performance of the offshore floating photovoltaic system through multiple dimensions, and can ensure the service life and operational stability of the photovoltaic system in the set sea area.

[0093] Reference Figure 5 As shown, an embodiment of the present invention further discloses a floating photovoltaic system, which is manufactured according to the design method described in any of the above embodiments.

[0094] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0095] It is easy for a person skilled in the art to think that any combination of the above embodiments is feasible, so any combination of the above embodiments is an implementation scheme of the present invention. However, due to space limitations, this specification will not describe them in detail here.

[0096] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0097] Similarly, it should be understood that in order to streamline the present invention and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof.

[0098] In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

Claims

1. A design method for an offshore floating photovoltaic system, characterized in that: The photovoltaic system comprises at least one photovoltaic array (1) having a square cross-section and a plurality of floating bodies (4) carrying the photovoltaic array (1), wherein the photovoltaic array (1) comprises a plurality of photovoltaic strings and an inverter (3) coupled to each photovoltaic string, wherein each photovoltaic string is composed of a plurality of photovoltaic components (101) connected in series and facing the same direction, wherein the number of photovoltaic components (101) in each photovoltaic string is the same; The design method comprises: Determining the range of the number of photovoltaic components (101) in each photovoltaic string according to the target temperature of a set sea area, the first electrical data of the photovoltaic components (101) and the second electrical data of the inverter (3), wherein the set sea area is the sea area where the photovoltaic system is to be placed; Determining the range of the array side length of each photovoltaic array (1) according to the wavelength of the waves in the set sea area; According to the component quantity range, the array side length range and the component size of the photovoltaic component (101), the target component quantity corresponding to each photovoltaic string and the photovoltaic string quantity corresponding to each photovoltaic array (1) are screened out; Determining the size and number of floating bodies for carrying each photovoltaic array (1) according to the target number of components and the number of photovoltaic strings, wherein each floating body (4) is fastened by cables and each is completely equipped with at least one photovoltaic component (101); The step of determining the component quantity range of the photovoltaic components (101) in each photovoltaic string according to the target temperature of the set sea area, the first electrical data of the photovoltaic components (101) and the second electrical data of the inverter (3) comprises: According to a target temperature of a set sea area and first electrical data of a photovoltaic module (101), a maximum open circuit voltage and a maximum operating voltage of each photovoltaic module (101) at the target temperature are determined; Determining a first component quantity value of photovoltaic components (101) corresponding to each photovoltaic string according to the second electrical data and the maximum open circuit voltage of the inverter (3); Determining a second component quantity value and a third component quantity value of the photovoltaic components (101) corresponding to each photovoltaic string according to the second electrical data and the maximum operating voltage of the inverter (3), wherein the third component quantity value is smaller than the second component quantity value and smaller than the first component quantity value; The third component quantity value is used as a lower limit value of the component quantity of photovoltaic components (101) in each photovoltaic string, and an upper limit value of the component quantity of photovoltaic components (101) in each photovoltaic string is determined based on the first component quantity value and the second component quantity value, so as to generate a corresponding component quantity range.

2. The design method according to claim 1, characterized in that: The method of determining the maximum open circuit voltage of each photovoltaic module (101) at the target temperature according to the target temperature of the set sea area and the first electrical data of the photovoltaic module (101) comprises: Determining a temperature difference between a target temperature of a set sea area and a test condition temperature corresponding to a photovoltaic module (101); A first weighting operation is performed on the temperature difference using the open circuit temperature coefficient of the photovoltaic module (101), and the maximum open circuit voltage of each photovoltaic module (101) at the target temperature is calculated based on the weighted temperature difference and the open circuit voltage of each photovoltaic module (101).

3. The design method according to claim 2, characterized in that: The method of determining the maximum operating voltage of each photovoltaic module (101) at the target temperature according to the target temperature of the set sea area and the first electrical data of the photovoltaic module (101) comprises: A second weighting operation is performed on the temperature difference using the operating temperature coefficient of the photovoltaic module (101), and the maximum operating voltage of each photovoltaic module (101) at the target temperature is calculated based on the weighted temperature difference and the operating voltage of each photovoltaic module (101).

4. The design method according to claim 1, characterized in that: Determining a first component quantity value of photovoltaic components (101) corresponding to each photovoltaic string according to the second electrical data of the inverter (3) and the maximum open-circuit voltage includes: Based on the maximum open-circuit voltage of the photovoltaic components (101) at the target temperature, the maximum number of photovoltaic components (101) corresponding to each photovoltaic string when the open-circuit voltage of the string is less than or equal to the maximum input voltage on the DC side of the inverter (3) is calculated and used as the first component quantity value.

5. The design method according to claim 1, characterized in that: The method of determining the second component quantity value of the photovoltaic components (101) corresponding to each photovoltaic string according to the second electrical data and the maximum operating voltage of the inverter (3) comprises: Based on the maximum operating voltage of the photovoltaic assembly (101) at the target temperature, the maximum number of photovoltaic assemblies (101) corresponding to each photovoltaic string when the string operating voltage is less than or equal to the maximum value of the MPPT voltage of the inverter (3) is calculated and used as the second assembly quantity value.

6. The design method according to claim 1, characterized in that: Determining the third component quantity value of the photovoltaic components (101) corresponding to each photovoltaic string according to the second electrical data and the maximum operating voltage of the inverter (3) comprises: Based on the maximum operating voltage of the photovoltaic module (101) at the target temperature, the maximum number of photovoltaic modules (101) corresponding to each photovoltaic string when the string operating voltage is greater than or equal to the minimum value of the MPPT voltage of the inverter (3) is calculated and used as the third module quantity value.

7. The design method according to claim 1, characterized in that: Determining the array side length range of each photovoltaic array (1) according to the wavelength of the sea waves in the set sea area comprises: One sixth of the wavelength of the sea waves in the set sea area is determined as the minimum value of the array side length of each photovoltaic array (1); One quarter of the wave length is determined as the maximum value of the array side length of each photovoltaic array (1); The array side length range of each photovoltaic array (1) is determined based on the minimum and maximum values ​​of the array side length.

8. The design method according to claim 1, characterized in that: The method further comprises: When the orientations of the photovoltaic components (101) in multiple photovoltaic strings are inconsistent, the output end of each photovoltaic string is coupled to a power optimizer.

9. A floating photovoltaic system, characterized in that: The system is manufactured according to the design method according to any one of claims 1-8.

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