Building integrated photovoltaic power generation system and method

Abstract

The application relates to the technical field of power generation and power supply, in particular to a building integrated photovoltaic (BIPV) power generation system and method, which solves the problem of increased cost of a power generation system caused by large cable demand in the related art. The system comprises: a photovoltaic panel, at least one combiner box, and at least one isolated inverter for power supply to a power grid system; wherein the photovoltaic panel is arranged on a building outer wall through a support, and the combiner box and the isolated inverter are arranged in the support between the photovoltaic panel and the building outer wall. The system of the application adopts the isolated inverter which has the advantages of small volume, light weight, low noise, high efficiency and the like, greatly reduces the volume of the building integrated photovoltaic power generation system, and enables the entire power generation system to be arranged on the building outer wall without greatly changing the building outer wall, thereby greatly reducing the cable demand and the cost.

Description

Technical Field

[0001] This application relates to the field of power generation and supply technology, and in particular to a building-integrated photovoltaic (BIPV) power generation system and method. Background Technology

[0002] Building-integrated photovoltaics (BIPV) combines new energy sources with buildings, representing a significant application of solar energy in green building and contributing to energy conservation and emission reduction. BIPV tightly integrates solar power generation with architecture, achieving both aesthetic appeal and energy efficiency. Thin-film solar photovoltaic panels, in particular, offer better performance in low-light conditions and are easier to integrate into buildings than crystalline silicon solar photovoltaic panels, making them especially suitable for use as photovoltaic curtain walls.

[0003] Current building-integrated photovoltaic (BIPV) power generation systems, especially in the application of photovoltaic (PV) curtain walls, are limited by parameters such as the size, weight, and operating temperature of isolated grid-connected inverters. This typically involves placing the PV inverter on the roof, connecting the PV panels to the inverter via DC cables, and then transmitting power to the building's electrical distribution room via AC cables. This results in a very large cable requirement, increasing the cost of BIPV and reducing system efficiency. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a building-integrated photovoltaic (BIPV) power generation system and method, which solves the technical problem of increased power generation system costs due to high cable requirements in related technologies.

[0005] In a first aspect, this application provides a building-integrated photovoltaic (BIPV) power generation system, the system comprising:

[0006] A photovoltaic panel, comprising multiple photovoltaic modules, is used to collect solar energy and convert the collected solar energy into electrical energy.

[0007] At least one combiner box, with its input end connected to the output end of the photovoltaic panel, is used to integrate the current of multiple photovoltaic modules;

[0008] At least one isolated inverter, with its input terminal connected to the output terminal of the combiner box and its output terminal connected to the power grid system, is used to adjust the integrated current and supply power to the power grid system.

[0009] The photovoltaic panel is mounted on the exterior wall of the building via a bracket, and the combiner box and the isolated inverter are located within the bracket between the photovoltaic panel and the exterior wall of the building.

[0010] Optionally, the thickness of the bracket is 10-20cm.

[0011] Optionally, in the photovoltaic panel, every 8-10 photovoltaic modules form a photovoltaic module string, every 10-12 photovoltaic module strings are connected to a combiner box, and every 2 combiner boxes are connected to an isolated inverter.

[0012] Optionally, the isolated inverter includes:

[0013] The first DC / DC module has its input terminal connected to the photovoltaic module and is used to increase and stabilize the DC voltage output by the photovoltaic module at a preset voltage value.

[0014] The second DC / DC module has its input terminal connected to the output terminal of the first DC / DC module, and is used to achieve electrical isolation between the photovoltaic module and the power grid.

[0015] The DC / AC module has its input terminal connected to the output terminal of the second DC / DC module, and is used to invert the DC voltage output by the second DC / DC module into AC voltage and output it to the power grid.

[0016] Optionally, the first DC / DC module is a Boost converter circuit.

[0017] Optionally, the second DC / DC module is an LLC resonant converter.

[0018] Optionally, the preset voltage value is a DC voltage value that makes the LLC resonant converter operate at the resonant frequency point.

[0019] Optionally, the DC / AC module is a T-type three-level module.

[0020] Secondly, a method for building-integrated photovoltaic (BIPV) power generation includes:

[0021] A photovoltaic panel collects solar energy and converts the collected solar energy into electrical energy; the photovoltaic panel includes multiple photovoltaic modules.

[0022] At least one combiner box integrates the current from multiple photovoltaic modules;

[0023] At least one isolated inverter adjusts the integrated current before supplying power to the power grid system;

[0024] The photovoltaic panel is mounted on the exterior wall of the building via a bracket, and the combiner box and the isolated inverter are located within the bracket between the photovoltaic panel and the exterior wall of the building.

[0025] Optionally, the at least one isolated inverter adjusts the integrated current before supplying power to the grid system, including:

[0026] The first DC / DC module in the isolated inverter increases and stabilizes the DC voltage output by the photovoltaic module at a preset voltage value.

[0027] The DC voltage output from the first DC / DC module in the isolated inverter is input to the second DC / DC module, causing the second DC / DC module to operate at the resonant frequency point. The input DC voltage and output DC voltage of the second DC / DC module are the same. At the same time, the high-frequency DC transformer of the second DC / DC module realizes electrical isolation between the photovoltaic module and the grid.

[0028] The DC / AC module in the isolated inverter inverts the DC voltage output from the second DC / DC module into AC voltage and outputs it to the power grid.

[0029] This application provides a building-integrated photovoltaic (BIPV) power generation system and method, comprising: a photovoltaic panel including multiple photovoltaic modules for collecting solar energy and converting the collected solar energy into electrical energy; at least one combiner box, with its input end connected to the output end of the photovoltaic panel, for integrating the current from the multiple photovoltaic modules; and at least one isolated inverter, with its input end connected to the output end of the combiner box and its output end connected to the power grid system, for adjusting the integrated current before supplying power to the power grid system; wherein the photovoltaic panel is mounted on the exterior wall of the building via a bracket, and the combiner box and the isolated inverter are disposed within the bracket between the photovoltaic panel and the exterior wall of the building. The system of this application utilizes an isolated inverter with numerous advantages such as small size, light weight, low noise, and high efficiency, significantly reducing the size of the BIPV power generation system. This allows the entire power generation system to be installed on the exterior wall of the building without significant alterations, greatly reducing cabling requirements and lowering costs. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a building-integrated photovoltaic power generation system provided in Embodiment 1 of the present invention;

[0032] Figure 2 This is a schematic diagram of an isolated inverter provided in Embodiment 1 of the present invention;

[0033] Figure 3 This is a topology diagram of an isolated inverter provided in Embodiment 1 of the present invention;

[0034] Figure 4 This is a flowchart of a photovoltaic building-integrated power generation method provided in Embodiment 2 of the present invention. Detailed Implementation

[0035] The following detailed description of the embodiments of this application, in conjunction with the accompanying drawings, will provide a thorough understanding of how this application uses technical means to solve technical problems and achieve corresponding technical effects, enabling its implementation. The embodiments of this application and the various features within them can be combined with each other without conflict, and all resulting technical solutions are within the protection scope of this application.

[0036] As the background technology shows, current building-integrated photovoltaic (BIPV) power generation systems, especially in the application of photovoltaic curtain walls, are limited by parameters such as the size, weight, and operating temperature of isolated grid-connected inverters. This necessitates placing the photovoltaic inverter on the roof, connecting the photovoltaic panels to the inverter via DC cables, and then transmitting power to the building's distribution room via AC cables. This results in a very large cable requirement, increasing the cost of BIPV and reducing system efficiency.

[0037] In view of this, this application provides a building-integrated photovoltaic power generation system and method, which solves the technical problem of increased power generation system cost due to large cable requirements in related technologies.

[0038] Example 1

[0039] Figure 1 This is a schematic diagram of a building-integrated photovoltaic (BIPV) power generation system provided in an embodiment of this application, as shown below. Figure 1 As shown, this system includes:

[0040] A photovoltaic panel, comprising multiple photovoltaic modules, is used to collect solar energy and convert the collected solar energy into electrical energy.

[0041] At least one combiner box, with its input end connected to the output end of the photovoltaic panel, is used to integrate the current of multiple photovoltaic modules;

[0042] At least one isolated inverter, with its input terminal connected to the output terminal of the combiner box and its output terminal connected to the power grid system, is used to adjust the integrated current and supply power to the power grid system.

[0043] The photovoltaic panel is mounted on the exterior wall of the building via a bracket, and the combiner box and the isolated inverter are located within the bracket between the photovoltaic panel and the exterior wall of the building.

[0044] It should be noted that, as Figure 1The photovoltaic panels shown are fixed to the exterior wall by brackets. The combiner box and isolated inverter are placed between the photovoltaic panels and the exterior wall, and then directly connected to the power distribution room for grid power supply. Since the isolated inverter itself has a transformer function, there is no need to connect an additional power frequency transformer, which reduces the complexity of the system and improves the system conversion efficiency.

[0045] It should be further noted that the system of this application adopts an isolated inverter with many advantages such as small size, light weight, low noise and high efficiency, which greatly reduces the size of the building-integrated photovoltaic power generation system. This allows the entire power generation system to be installed on the exterior wall of the building without significantly altering the exterior wall, thereby greatly reducing the need for cables and lowering costs.

[0046] Preferably, the entire power generation system can be installed on the exterior wall of the south, east and / or west side to achieve the best power generation effect while reducing costs.

[0047] Optionally, in the photovoltaic panel, every 8-10 photovoltaic modules form a photovoltaic module string, every 10-12 photovoltaic module strings are connected to a combiner box, and every 2 combiner boxes are connected to an isolated inverter.

[0048] It should be noted that the photovoltaic building integrated power generation system of this application is not limited to only one combiner box and isolated inverter. It can be configured as a power supply group consisting of two combiner boxes each connected to 10-12 strings of photovoltaic modules and one isolated inverter. Multiple power supply groups can be set up according to the number of photovoltaic modules in the photovoltaic panel and specific needs to meet user requirements.

[0049] Specifically, the combiner box is a DC combiner box.

[0050] Please see Figure 2 This embodiment provides an isolated inverter, comprising:

[0051] First DC / DC module 1, second DC / DC module 2, and DC / AC module 3.

[0052] The input terminal of the first DC / DC module 1 is connected to the photovoltaic module 4, and is used to increase the DC voltage output by the photovoltaic module 4 and stabilize it at a preset voltage value.

[0053] The second DC / DC module 2 has its input terminal connected to the output terminal of the first DC / DC module 1, and is used to achieve electrical isolation between the photovoltaic module 4 and the power grid 5.

[0054] DC / AC module 3 has its input terminal connected to the output terminal of the second DC / DC module 2, and is used to invert the DC voltage output by the second DC / DC module 2 into AC voltage and output it to the power grid 5.

[0055] Preferably, this embodiment implements a method such as Figure 3 The isolated inverter topology shown has a second DC / DC module 2, which is an LLC resonant converter with soft-switching characteristics. This can increase the switching frequency and reduce the size of the inductor and transformer. When the LLC resonant converter operates at its resonant frequency, the input and output voltages remain unchanged. At this time, the second DC / DC module 2, which is used to achieve electrical isolation, has the highest operating efficiency. Therefore, in this embodiment, it is preferable to set the preset voltage value to the DC voltage that makes the second DC / DC module 2 (LLC resonant converter) operate at its resonant frequency. This can significantly improve the voltage transmission efficiency of the isolated inverter in this embodiment, thereby improving the operating efficiency of the isolated inverter.

[0056] If only a two-stage structure consisting of the second DC / DC module 2 (LLC resonant converter) and the DC / AC module 3 is used, two scenarios will exist:

[0057] In one scenario, if the LLC resonant converter operates at its resonant frequency, although the LLC resonant converter with electrical isolation has high efficiency, its input and output voltages remain constant, resulting in an excessively small operating voltage range for the isolated inverter, making it unsuitable for photovoltaic modules with different voltages.

[0058] In another scenario, if the LLC resonant converter operates at a non-resonant frequency, then although the voltage can be adjusted through the LLC resonant converter to allow the isolated inverter to meet a wider operating voltage range, the LLC resonant converter has low efficiency, which in turn leads to low efficiency of the isolated inverter.

[0059] Therefore, in this embodiment, a first DC / DC module 1 is provided before the second DC / DC module 2. The first DC / DC module is preferably a Boost converter circuit. The voltage is boosted to 1000V and connected to the LLC resonant converter via a switching frequency higher than 50kHz. This ensures a wide voltage input range for the photovoltaic module (e.g., an input voltage operating range of 200-1000V) and improves the efficiency of the LLC resonant converter by operating it at its resonant frequency. The efficiency of this isolated inverter is significantly higher than that of inverters using a phase-shifted full-bridge for electrical isolation. It also enables soft switching between the primary and secondary sides, ensuring transmission efficiency while maintaining isolation. Furthermore, it guarantees a wide input voltage range, high operating frequency, and boasts advantages such as small size, light weight, high power density, high conversion efficiency, and electrical isolation.

[0060] In this embodiment, the isolated inverter includes a three-stage conversion structure. The DC voltage output by the photovoltaic module 4 is increased and stabilized at a preset voltage value (e.g., 1000V) through the Boost boost circuit, so that when the DC voltage is transmitted to the LLC resonant converter, the LLC resonant converter can operate at the resonant frequency point. Then, the DC voltage is inverted into AC voltage and sent to the grid. In this way, the isolated inverter can start and work normally even at low voltage, and the working efficiency of the second DC / DC module is also achieved.

[0061] Preferably, the DC / AC module is a T-type three-level module, which can enable the photovoltaic inverter to achieve higher efficiency; the LLC resonant converter is connected to the DC / AC module through a high-frequency transformer, and the selection of a T-type three-level module can ensure the working efficiency of the inverter.

[0062] It is understandable that there are supporting capacitors between the Boost converter and the LLC resonant converter, and between the LLC resonant converter and the T-type three-level module. A filter circuit for reducing high-frequency components is also provided after the T-type three-level module, so that the AC voltage output by the T-type three-level module can be connected to the power grid.

[0063] It is worth noting that the photovoltaic module in this embodiment can be not only a crystalline silicon photovoltaic module, but also a CIGS thin-film photovoltaic module. CIGS thin-film photovoltaic modules have a much higher voltage and lower current than crystalline silicon. The DC bus rating of the isolated inverter in this embodiment is sufficient to support its application in CIGS thin-film photovoltaic modules, and it also has the advantages of small size and light weight. Traditional isolated inverters are up to 20mm thick, while this embodiment, by utilizing the soft-switching characteristics of the LLC resonant converter, increases the switching frequency and reduces the size of inductors and transformers, reducing the thickness of the isolated inverter to 10mm. This is particularly suitable for building-integrated photovoltaics (BIPV) applications, significantly reducing cable usage and lowering costs. Furthermore, the isolated inverter in this embodiment has a high power density. Traditional isolated inverters have a power density of 149kW / m³. Although this isolated inverter uses a three-stage topology, the increased switching frequency reduces the size of related components such as inductors and transformers. The power density of this three-stage isolated inverter exceeds 260kW / m³, significantly better than traditional isolated inverters.

[0064] Preferably, the thickness of the support is 10-20cm.

[0065] As can be seen from the above, the thickness of the isolated inverter in this application can be reduced to 10mm, thereby enabling the following... Figure 1The diagram shows that placing the isolated inverter inside the bracket protects the inverter while reducing the overall size and weight of the power generation system, allowing the power generation system to be installed on the exterior wall without significantly altering the exterior wall.

[0066] In summary, this application provides a building-integrated photovoltaic (BIPV) power generation system, comprising: a photovoltaic panel including multiple photovoltaic modules for collecting solar energy and converting the collected solar energy into electrical energy; at least one combiner box, with its input end connected to the output end of the photovoltaic panel, for integrating the current from the multiple photovoltaic modules; and at least one isolated inverter, with its input end connected to the output end of the combiner box and its output end connected to the power grid system, for adjusting the integrated current before supplying power to the power grid system. The photovoltaic panel is mounted on the exterior wall of the building via a bracket, and the combiner box and the isolated inverter are housed within the bracket between the photovoltaic panel and the exterior wall. This application's system utilizes an isolated inverter with advantages such as small size, light weight, low noise, and high efficiency, significantly reducing the size of the BIPV power generation system. This allows the entire power generation system to be installed on the exterior wall of the building without significant alterations, greatly reducing cabling requirements and costs.

[0067] Example 2

[0068] like Figure 4 As shown, this embodiment provides a building-integrated photovoltaic (BIPV) power generation method, including:

[0069] S401. Photovoltaic panels collect solar energy and convert the collected solar energy into electrical energy;

[0070] In step S401, the photovoltaic panel includes multiple photovoltaic modules.

[0071] S402, At least one combiner box integrates the current of multiple photovoltaic modules;

[0072] S403. At least one isolated inverter adjusts the integrated current and supplies power to the power grid system;

[0073] The photovoltaic panel is mounted on the exterior wall of the building via a bracket, and the combiner box and the isolated inverter are located within the bracket between the photovoltaic panel and the exterior wall of the building.

[0074] Optionally, the at least one isolated inverter adjusts the integrated current before supplying power to the grid system, including:

[0075] The first DC / DC module in the isolated inverter increases and stabilizes the DC voltage output by the photovoltaic module at a preset voltage value.

[0076] The DC voltage output from the first DC / DC module in the isolated inverter is input to the second DC / DC module, causing the second DC / DC module to operate at the resonant frequency point. The input DC voltage and output DC voltage of the second DC / DC module are the same. At the same time, the high-frequency DC transformer of the second DC / DC module realizes electrical isolation between the photovoltaic module and the grid.

[0077] The DC / AC module in the isolated inverter inverts the DC voltage output from the second DC / DC module into AC voltage and outputs it to the power grid.

[0078] The first DC / DC module is preferably a Boost converter, the second DC / DC module is an LLC resonant converter, and the DC / AC module is a T-type three-level module.

[0079] When the LLC resonant converter operates at its resonant frequency, the input and output voltages of the LLC resonant converter remain unchanged. At this time, the second DC / DC module used to achieve electrical isolation has the highest operating efficiency. Therefore, in this embodiment, it is preferable to set the preset voltage value to the DC voltage that makes the LLC resonant converter operate at its resonant frequency. This can significantly improve the voltage transmission efficiency of the isolated photovoltaic inverter in this embodiment, thereby improving the operating efficiency of the isolated photovoltaic inverter.

[0080] In this embodiment, the isolated inverter in the building-integrated photovoltaic (BIPV) power generation system can achieve soft switching between the primary and secondary sides. While achieving isolation, it ensures transmission efficiency and a wide input voltage range. It also has a high operating frequency and advantages such as small size, light weight, high power density, high conversion efficiency, and electrical isolation. This significantly reduces the size of the BIPV power generation system, allowing the entire power generation system to be installed on the building exterior wall without significant alterations to the building exterior wall. This greatly reduces cable requirements and lowers costs.

[0081] In the several embodiments provided in this application, it should be understood that the disclosed methods can also be implemented in other ways. The method embodiments described above are merely illustrative.

[0082] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0083] Although the embodiments disclosed in this application are as described above, the above content is merely for the purpose of facilitating understanding of this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A building-integrated photovoltaic (BIPV) power generation system, characterized in that, The system includes: A photovoltaic panel, comprising multiple photovoltaic modules, is used to collect solar energy and convert the collected solar energy into electrical energy. At least one combiner box, with its input end connected to the output end of the photovoltaic panel, is used to integrate the current of multiple photovoltaic modules; At least one isolated inverter, with its input terminal connected to the output terminal of the combiner box and its output terminal connected to the power grid system, is used to adjust the integrated current and supply power to the power grid system. The photovoltaic panel is mounted on the exterior wall of the building via a bracket, and the combiner box and the isolated inverter are located within the bracket between the photovoltaic panel and the exterior wall of the building. The isolated inverter includes: The first DC / DC module has its input terminal connected to the photovoltaic module and is used to increase and stabilize the DC voltage output by the photovoltaic module at a preset voltage value. The second DC / DC module has its input terminal connected to the output terminal of the first DC / DC module, and is used to achieve electrical isolation between the photovoltaic module and the power grid. The DC / AC module has its input terminal connected to the output terminal of the second DC / DC module, and is used to invert the DC voltage output by the second DC / DC module into AC voltage and output it to the power grid. The first DC / DC module is a Boost converter; the second DC / DC module is an LLC resonant converter, which increases the switching frequency based on the soft-switching characteristics of the LLC resonant converter to reduce the size of the inductor and transformer, thereby reducing the thickness of the isolated inverter; the preset voltage value is the DC voltage value that makes the LLC resonant converter operate at the resonant frequency point, so as to ensure transmission efficiency while achieving isolation, and can be applied to photovoltaic modules with different voltages; the DC / AC module is a T-type three-level module.

2. The system according to claim 1, characterized in that, The thickness of the support is 10-20cm.

3. The system according to claim 1, characterized in that, In the photovoltaic panel, every 8-10 photovoltaic modules form a photovoltaic module string, every 10-12 photovoltaic module strings are connected to a combiner box, and every 2 combiner boxes are connected to an isolated inverter.

4. A method for building-integrated photovoltaic (BIPV) power generation, characterized in that, include: Photovoltaic panels collect solar energy and convert it into electrical energy; The photovoltaic panel includes multiple photovoltaic modules; At least one combiner box integrates the current from multiple photovoltaic modules; At least one isolated inverter adjusts the integrated current before supplying power to the grid system; The photovoltaic panel is mounted on the exterior wall of the building via a bracket, and the combiner box and the isolated inverter are located within the bracket between the photovoltaic panel and the exterior wall of the building. The isolated inverter includes: The first DC / DC module has its input terminal connected to the photovoltaic module and is used to increase and stabilize the DC voltage output by the photovoltaic module at a preset voltage value. The second DC / DC module has its input terminal connected to the output terminal of the first DC / DC module, and is used to achieve electrical isolation between the photovoltaic module and the power grid. The DC / AC module has its input terminal connected to the output terminal of the second DC / DC module, and is used to invert the DC voltage output by the second DC / DC module into AC voltage and output it to the power grid. The first DC / DC module is a Boost converter; the second DC / DC module is an LLC resonant converter, which increases the switching frequency based on the soft-switching characteristics of the LLC resonant converter to reduce the size of the inductor and transformer, thereby reducing the thickness of the isolated inverter; the preset voltage value is the DC voltage value that makes the LLC resonant converter operate at the resonant frequency point, so as to ensure transmission efficiency while achieving isolation, and can be applied to photovoltaic modules with different voltages; the DC / AC module is a T-type three-level module.

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