Integrated photovoltaic module and power generation system

Abstract

The application provides an integrated photovoltaic module and a power generation system. The integrated photovoltaic module comprises a DC / DC converter, a photovoltaic junction box, and first and second photovoltaic cells which are stacked and different in material. The DC / DC converter is located in the photovoltaic junction box. The first and second photovoltaic cells are connected in series between a first input end and a second input end of the DC / DC converter. A connection between the first and second photovoltaic cells is connected to a third input end of the DC / DC converter. An output end of the DC / DC converter is connected to an output end of the integrated photovoltaic module. The first and second photovoltaic cells are used to convert absorbed solar energy into electric energy. The DC / DC converter is used to compensate for a difference between an output current of the first photovoltaic cell and an output current of the second photovoltaic cell. Thus, the outputs of the two photovoltaic cells in the dual-junction photovoltaic module are adapted, and the photoelectric conversion efficiency of the dual-junction photovoltaic module is maximized.

Description

Technical Field

[0001] This application relates to the field of power technology, and in particular to an integrated photovoltaic module and power generation system. Background Technology

[0002] Currently, most photovoltaic (PV) modules used on a large scale are single-junction solar cells. Single-junction solar cells are made of a single type of material (such as silicon) and can only perform photoelectric conversion on sunlight of a specific wavelength, resulting in low photoelectric conversion efficiency of PV modules. Based on this, existing technology provides a PV module using multi-layered solar cells (such as double-junction solar cells). Multi-layered solar cells are composed of multiple solar cells made of different materials stacked together, which can perform photoelectric conversion on sunlight of different wavelengths, thereby improving the photoelectric conversion efficiency of the PV module.

[0003] Because the output characteristics (including output voltage and output current) of the two types of solar cells in a double-junction solar cell differ significantly, they cannot be directly connected in series or parallel. Taking a crystalline silicon-perovskite tandem double-junction solar cell as an example: for a crystalline silicon solar cell, its output voltage is 40V and its output current is 10A, resulting in the highest photoelectric conversion efficiency; for a perovskite solar cell, its output voltage is 400V and its output current is 1A, resulting in the highest photoelectric conversion efficiency. Based on this, existing photovoltaic modules using double-junction solar cells optimize the photovoltaic module manufacturing process. For example, by changing the area of ​​the solar cells to alter the output characteristics of the crystalline silicon solar cell with the highest photoelectric conversion efficiency, or by changing the chemical materials coated on the panel to alter the output characteristics of the perovskite solar cell with the highest photoelectric conversion efficiency, the output characteristics of the two types of solar cells can be made consistent, allowing them to be directly connected in series or parallel. Obviously, when the output characteristics of the double-junction solar cells are consistent, the photoelectric conversion efficiency of at least one type of solar cell in the double-junction solar cell is no longer the highest. In other words, consistent output characteristics and high photoelectric conversion efficiency are mutually exclusive.

[0004] In summary, it is particularly important to adapt the output of the two types of solar cells in a double-junction solar cell while maintaining the high photoelectric conversion efficiency of both types of solar cells. Summary of the Invention

[0005] This application provides an integrated photovoltaic module and power generation system that not only enables the output of the two types of photovoltaic cells in a dual-junction photovoltaic module to be matched, but also maximizes the photoelectric conversion efficiency of the dual-junction photovoltaic module.

[0006] In a first aspect, this application provides an integrated photovoltaic module, comprising a DC / DC converter, a photovoltaic junction box, and a first photovoltaic cell and a second photovoltaic cell stacked together and made of different materials. The DC / DC converter is located inside the photovoltaic junction box. The first and second photovoltaic cells are connected in series between a first input terminal and a second input terminal of the DC / DC converter. The connection point between the first and second photovoltaic cells is connected to a third input terminal of the DC / DC converter. The output terminal of the DC / DC converter is connected to the output terminal of the integrated photovoltaic module. The first and second photovoltaic cells are used to convert absorbed solar energy into electrical energy. The DC / DC converter is used to compensate for the difference between the output current of the first and second photovoltaic cells.

[0007] In this embodiment, the integrated photovoltaic module provided in this application is a dual-junction photovoltaic module. Because the output current of the first photovoltaic cell in the integrated photovoltaic module differs from that of the second photovoltaic cell, they cannot be directly connected in series. Therefore, when the two photovoltaic cells in the integrated photovoltaic module are connected in series, the DC / DC converter in the integrated photovoltaic module can compensate for the difference in the output current of the two photovoltaic cells, enabling the two photovoltaic cells in the integrated photovoltaic module to operate in series through the DC / DC converter. In other words, the outputs of the two photovoltaic cells in the integrated photovoltaic module are adapted. Furthermore, since the method of adapting the outputs of the two photovoltaic cells in the integrated photovoltaic module through the DC / DC converter does not require special treatment of the photovoltaic cell materials or manufacturing processes, it can accommodate most dual-junction photovoltaic modules on the market and save related costs. It also does not change the original output characteristics of the two photovoltaic cells in the integrated photovoltaic module. Therefore, the two photovoltaic cells in the integrated photovoltaic module can output according to their respective output characteristics when their photoelectric conversion efficiency is at its highest. Thus, the integrated photovoltaic module can achieve the highest photoelectric conversion efficiency. In addition, the DC / DC converter is located inside the photovoltaic junction box of the integrated photovoltaic module, and the junction box is located on the back of the integrated photovoltaic module. Generally, the junction box is assembled with the integrated photovoltaic module at the factory, so it does not increase the size of the integrated photovoltaic module, which is conducive to the miniaturization design of the integrated photovoltaic module.

[0008] In conjunction with the first aspect, in a first possible implementation, the number of output terminals of the integrated photovoltaic module is 2.

[0009] In this embodiment, the integrated photovoltaic module has only two output terminals: a positive output terminal and a negative output terminal. This allows the integrated photovoltaic module to be connected in series or parallel like a traditional single-junction photovoltaic module. Compared to a double-junction photovoltaic module with four output terminals, this effectively saves on wiring costs between the integrated photovoltaic module and other equipment (such as an inverter).

[0010] In conjunction with the first aspect or the first possible implementation of the first aspect, in a second possible implementation, the DC / DC converter includes a first switching transistor, a second switching transistor, an inductor, and a controller. The first and second switching transistors are connected in series between the first and second input terminals of the DC / DC converter, and the inductor is connected between the third input terminal of the DC / DC converter and the connection point of the first and second switching transistors. The controller is used to control the complementary conduction of the first and second switching transistors to compensate for the difference between the output current of the first photovoltaic cell and the output current of the second photovoltaic cell.

[0011] In this embodiment, the DC / DC converter can compensate for the difference between the output currents of the first and second photovoltaic cells by controlling the complementary conduction of the first and second switching transistors. This is achieved by ensuring that the current at the third input terminal of the DC / DC converter is the absolute value of the difference between the output currents of the first and second photovoltaic cells, and that the direction of the current at the third input terminal is the same as the direction of the output current of the photovoltaic cell with the smaller output current. The output current directions of the first and second photovoltaic cells include those flowing into and out of the connection point between them. This compensation method is simple and easy to implement.

[0012] In conjunction with the second possible implementation of the first aspect, in the third possible implementation, the output current of the first photovoltaic cell is greater than the output current of the second photovoltaic cell; the controller is used to control the first switch and the second switch to conduct in a complementary manner and the duty cycle of the first switch is greater than the duty cycle of the second switch.

[0013] Secondly, this application provides an integrated photovoltaic module, which includes a DC / DC converter, a photovoltaic junction box, and a first photovoltaic cell and a second photovoltaic cell stacked together with different materials. The DC / DC converter is located inside the photovoltaic junction box. The first output terminal of both the first and second photovoltaic cells are connected to the first input terminal of the DC / DC converter. The second output terminal of the first photovoltaic cell is connected to the second input terminal of the DC / DC converter, and the second output terminal of the second photovoltaic cell is connected to the third input terminal of the DC / DC converter. The first and second photovoltaic cells are used to convert absorbed solar energy into electrical energy. The first output terminal of the DC / DC converter is connected to the first input terminal of the DC / DC converter and the first output terminal of the integrated photovoltaic module. The second output terminal of the DC / DC converter is connected to the third input terminal of the DC / DC converter and the second output terminal of the integrated photovoltaic module. The DC / DC converter is used to convert the output voltage of the first photovoltaic cell to the output voltage of the second photovoltaic cell. The polarity of the first output terminal of the first photovoltaic cell is the same as the polarity of the first output terminal of the second photovoltaic cell, and opposite to the polarity of the second output terminal of the DC / DC converter.

[0014] In this embodiment, the integrated photovoltaic module provided in this application is a dual-junction photovoltaic module. Because the output voltage of the first photovoltaic cell in the integrated photovoltaic module differs from that of the second photovoltaic cell, the first and second photovoltaic cells cannot be directly connected in parallel. Therefore, when the first photovoltaic cell in the integrated photovoltaic module is connected in parallel with the second photovoltaic cell through a DC / DC converter, the DC / DC converter can convert the output voltage of the first photovoltaic cell in the integrated photovoltaic module to the output voltage of the second photovoltaic cell. This makes the output voltage of the first photovoltaic cell in the integrated photovoltaic module after conversion by the DC / DC converter the same as the output voltage of the second photovoltaic cell. This allows the two types of photovoltaic cells in the integrated photovoltaic module to operate in parallel through the DC / DC converter; in other words, it enables the outputs of the two types of photovoltaic cells in the integrated photovoltaic module to be compatible. Furthermore, because the DC / DC converter adapts the outputs of the two photovoltaic cells in the integrated photovoltaic module, it does not require special treatment of the photovoltaic cell materials or manufacturing processes. Therefore, it can accommodate most dual-junction photovoltaic modules on the market while saving related costs, and it does not change the original output characteristics of the two photovoltaic cells in the integrated photovoltaic module. Thus, the two photovoltaic cells in the integrated photovoltaic module can output according to their respective output characteristics at their highest photoelectric conversion efficiency, thereby achieving the highest photoelectric conversion efficiency for the integrated photovoltaic module. In addition, the DC / DC converter is located inside the photovoltaic junction box of the integrated photovoltaic module, which is located on the back of the integrated photovoltaic module. Generally, the junction box is assembled with the integrated photovoltaic module at the factory, thus not increasing the size of the integrated photovoltaic module and facilitating miniaturization design.

[0015] In conjunction with the second aspect, in the first possible implementation, the number of output terminals of the integrated photovoltaic modules is 2.

[0016] In this embodiment, the integrated photovoltaic module has only two output terminals: a positive output terminal and a negative output terminal. This allows the integrated photovoltaic module to be connected in series or parallel like a traditional single-junction photovoltaic module. Compared to a double-junction photovoltaic module with four output terminals, this effectively saves on wiring costs between the integrated photovoltaic module and other equipment (such as an inverter).

[0017] In conjunction with the second aspect or the first possible implementation of the second aspect, in the second possible implementation, when the polarity of the first output terminal of the first photovoltaic cell is negative, the DC / DC converter includes a BUCK circuit or a BOOST circuit.

[0018] In this embodiment, when the two types of photovoltaic cells in the integrated photovoltaic module are connected with a common negative terminal, the negative input terminal of the DC / DC converter is connected to the negative output terminals of both photovoltaic cells and the negative output terminal of the DC / DC converter, and the positive output terminal of the second photovoltaic cell is connected to the positive output terminal of the DC / DC converter. This connection allows the first photovoltaic cell to be connected in parallel with the second photovoltaic cell through the DC / DC converter. Furthermore, with the two types of photovoltaic cells in the integrated photovoltaic module connected with a common negative terminal, the DC / DC converter can have various structures, resulting in diverse and flexible structures for the integrated photovoltaic module.

[0019] In conjunction with the second aspect or the first possible implementation of the second aspect, in the third possible implementation, when the polarity of the first output terminal of the first photovoltaic cell is positive, the DC / DC converter includes an inverted circuit of the BUCK circuit or an inverted circuit of the BOOST circuit.

[0020] In this embodiment, when the two types of photovoltaic cells in the integrated photovoltaic module are connected with a common positive electrode, the positive input terminal of the DC / DC converter is connected to the positive output terminals of both photovoltaic cells and the positive output terminal of the DC / DC converter, and the negative output terminal of the second photovoltaic cell is connected to the negative output terminal of the DC / DC converter. This connection allows the first photovoltaic cell to be connected in parallel with the second photovoltaic cell through the DC / DC converter. Furthermore, with the two types of photovoltaic cells in the integrated photovoltaic module connected with a common positive electrode, the DC / DC converter can have various structures, resulting in diverse and flexible structures for the integrated photovoltaic module.

[0021] Thirdly, this application provides a power generation system including a photovoltaic module and a DC / DC converter. The photovoltaic module includes a first photovoltaic cell and a second photovoltaic cell stacked together and made of different materials. The first and second photovoltaic cells are connected in series between a first output terminal and a second output terminal of the photovoltaic module. The connection point of the first and second photovoltaic cells is connected to a third output terminal of the photovoltaic module. The first and second photovoltaic cells are used to convert absorbed solar energy into electrical energy. The first input terminal of the DC / DC converter is connected to the first output terminal of the photovoltaic module, the second input terminal of the DC / DC converter is connected to the second output terminal of the photovoltaic module, and the third input terminal of the DC / DC converter is connected to the third output terminal of the photovoltaic module. The DC / DC converter is used to compensate for the difference between the output current of the first photovoltaic cell and the output current of the second photovoltaic cell.

[0022] In this embodiment, the photovoltaic module provided in this application is a double-junction photovoltaic module, that is, a photovoltaic module using double-junction solar cells. Because the output current of the first photovoltaic cell in the photovoltaic module differs from that of the second photovoltaic cell, the first and second photovoltaic cells cannot be directly connected in series. Therefore, when the two photovoltaic cells in the photovoltaic module are connected in series, the DC / DC converter can compensate for the difference in output current between the two photovoltaic cells in the connected photovoltaic module, enabling the two photovoltaic cells in the photovoltaic module to operate in series through the DC / DC converter. In other words, the outputs of the two photovoltaic cells in the photovoltaic module are matched. Furthermore, since the method of matching the outputs of the two photovoltaic cells in the photovoltaic module through the DC / DC converter does not require special treatment of the photovoltaic cell materials or manufacturing processes, it can accommodate most double-junction photovoltaic modules on the market and save related costs. It also does not change the original output characteristics of the two photovoltaic cells in the photovoltaic module. Therefore, the two photovoltaic cells in the photovoltaic module can output according to their respective output characteristics when their photoelectric conversion efficiency is at its highest. Thus, the double-junction photovoltaic module can achieve the highest photoelectric conversion efficiency, thereby increasing the power generation of the power generation system.

[0023] In conjunction with the third aspect, in a first possible implementation, the DC / DC converter includes a first switch, a second switch, an inductor, and a controller. The first and second switches are connected in series between the first and second input terminals of the DC / DC converter, and the inductor is connected between the third input terminal of the DC / DC converter and the junction of the first and second switches. The controller is used to control the complementary conduction of the first and second switches to compensate for the difference between the output current of the first photovoltaic cell and the output current of the second photovoltaic cell.

[0024] In this embodiment, the DC / DC converter can compensate for the difference between the output currents of the first and second photovoltaic cells by controlling the complementary conduction of the first and second switching transistors. This is achieved by ensuring that the current at the third input terminal of the DC / DC converter is the absolute value of the difference between the output currents of the first and second photovoltaic cells, and that the direction of the current at the third input terminal is the same as the direction of the output current of the photovoltaic cell with the smaller output current. The output current directions of the first and second photovoltaic cells include those flowing into and out of the connection point between them. This compensation method is simple and easy to implement.

[0025] In conjunction with the first possible implementation of the third aspect, in the second possible implementation, the output current of the first photovoltaic cell is greater than the output current of the second photovoltaic cell; the controller is used to control the first switch and the second switch to conduct in a complementary manner and the duty cycle of the first switch is greater than the duty cycle of the second switch.

[0026] In combination with any of the third aspect to the second possible implementation of the third aspect, in the third possible implementation, the number of output terminals of the DC / DC converter is 2.

[0027] In this embodiment, the DC / DC converter has only two output terminals: a positive output terminal and a negative output terminal. This allows the dual-junction photovoltaic modules configured with the DC / DC converter to be connected in series or parallel like traditional single-junction photovoltaic modules. Compared to dual-junction photovoltaic modules with four output terminals, this effectively saves on wiring costs between photovoltaic modules and other equipment (such as inverters).

[0028] In conjunction with any of the third aspect to the third possible implementation, in the fourth possible implementation, the power generation system includes multiple photovoltaic modules, multiple DC / DC converters and inverters, with the multiple photovoltaic modules connected one-to-one with the multiple DC / DC converters, the output terminals of the multiple DC / DC converters connected in series with the input terminal of the inverter, and the output terminal of the inverter used to connect to the power grid or a load.

[0029] In this embodiment, the output terminals of all DC / DC converters in the power generation system are connected in series. By flexibly setting the number of DC / DC converters connected in series, the output power range of all DC / DC converters can be expanded, thereby making the power generation system suitable for application scenarios with more power level requirements.

[0030] Fourthly, this application provides a power generation system comprising a photovoltaic module and a DC / DC converter. The photovoltaic module includes a first photovoltaic cell and a second photovoltaic cell stacked together and made of different materials. The first output terminals of both the first and second photovoltaic cells are connected to the first output terminal of the photovoltaic module. The second output terminal of the first photovoltaic cell is connected to the second output terminal of the photovoltaic module, and the second output terminal of the second photovoltaic cell is connected to the third output terminal of the photovoltaic module. The first and second photovoltaic cells are used to convert absorbed solar energy into electrical energy. The first input terminal of the DC / DC converter is connected to the first output terminal of the photovoltaic module and the first output terminal of the DC / DC converter. The second input terminal of the DC / DC converter is connected to the second output terminal of the photovoltaic module, and the third input terminal of the DC / DC converter is connected to the third output terminal of the photovoltaic module and the second output terminal of the DC / DC converter. The DC / DC converter is used to convert the output voltage of the first photovoltaic cell to the output voltage of the second photovoltaic cell. The polarity of the first output terminal of the first photovoltaic cell is the same as the polarity of the first output terminal of the second photovoltaic cell, and opposite to the polarity of the second output terminal of the DC / DC converter.

[0031] In this embodiment, the photovoltaic module provided in this application is a dual-junction photovoltaic module. Because the output voltage of the first photovoltaic cell in the photovoltaic module is different from that of the second photovoltaic cell, the first and second photovoltaic cells cannot be directly connected in parallel. Therefore, when the first photovoltaic cell in the photovoltaic module is connected in parallel with the second photovoltaic cell through a DC / DC converter, the DC / DC converter can convert the output voltage of the first photovoltaic cell in the connected photovoltaic module to the output voltage of the second photovoltaic cell. This makes the output voltage of the first photovoltaic cell in the photovoltaic module after conversion by the DC / DC converter the same as the output voltage of the second photovoltaic cell. Thus, the two types of photovoltaic cells in the photovoltaic module can work in parallel through the DC / DC converter; in other words, the outputs of the two types of photovoltaic cells in the photovoltaic module are adapted. Furthermore, since the output of the two photovoltaic cells in a photovoltaic module is adapted through a DC / DC converter, there is no special requirement for the materials of the photovoltaic cells or for special processing in the manufacturing process. Therefore, it can be compatible with most dual-junction photovoltaic modules on the market and save related costs. At the same time, it does not change the original output characteristics of the two photovoltaic cells in the photovoltaic module. Thus, the two photovoltaic cells in the photovoltaic module can output according to their respective output characteristics when their photoelectric conversion efficiency is the highest. Therefore, dual-junction photovoltaic modules can achieve the highest photoelectric conversion efficiency, thereby increasing the power generation of the power generation system.

[0032] In conjunction with the fourth aspect, in a first possible implementation, when the polarity of the first output terminal of the first photovoltaic cell is negative, the DC / DC converter includes a BUCK circuit or a BOOST circuit.

[0033] In this embodiment, when the two types of photovoltaic cells in the photovoltaic module are connected with a common negative terminal, the negative input terminal of the DC / DC converter is connected to the negative output terminals of both photovoltaic cells and the negative output terminal of the DC / DC converter, and the positive output terminal of the second photovoltaic cell is connected to the positive output terminal of the DC / DC converter. This connection allows the first photovoltaic cell to be connected in parallel with the second photovoltaic cell through the DC / DC converter. Furthermore, with the two types of photovoltaic cells in the photovoltaic module connected with a common negative terminal, the DC / DC converter can have various structures, resulting in diverse and flexible power generation system structures.

[0034] In conjunction with the fourth aspect, in a second possible implementation, when the polarity of the first output terminal of the first photovoltaic cell is positive, the DC / DC converter includes an inverted circuit of the BUCK circuit or an inverted circuit of the BOOST circuit.

[0035] In this embodiment, when the two types of photovoltaic cells in the photovoltaic module are connected with a common positive terminal, the positive input terminal of the DC / DC converter is connected to the positive output terminals of both photovoltaic cells and the positive output terminal of the DC / DC converter, and the negative output terminal of the second photovoltaic cell is connected to the negative output terminal of the DC / DC converter. This connection allows the first photovoltaic cell to be connected in parallel with the second photovoltaic cell through the DC / DC converter. Furthermore, with the two types of photovoltaic cells in the photovoltaic module connected with a common positive terminal, the DC / DC converter can have various structures, resulting in diverse and flexible power generation system structures.

[0036] In combination with any of the fourth aspect to the second possible implementation of the fourth aspect, in the third possible implementation, the number of output terminals of the DC / DC converter is 2.

[0037] In this embodiment, the DC / DC converter has only two output terminals: a positive output terminal and a negative output terminal. This allows the dual-junction photovoltaic modules configured with the DC / DC converter to be connected in series or parallel like traditional single-junction photovoltaic modules. Compared to dual-junction photovoltaic modules with four output terminals, this effectively saves on wiring costs between photovoltaic modules and other equipment (such as inverters).

[0038] In conjunction with any of the fourth aspect to the third possible implementation, in the fourth possible implementation, the power generation system includes multiple photovoltaic modules, multiple DC / DC converters and inverters, with the multiple photovoltaic modules connected one-to-one with the multiple DC / DC converters, the output terminals of the multiple DC / DC converters connected in series with the input terminal of the inverter, and the output terminal of the inverter used to connect to the power grid or a load.

[0039] In this embodiment, the output terminals of all DC / DC converters in the power generation system are connected in series. By flexibly setting the number of DC / DC converters connected in series, the output power range of all DC / DC converters can be expanded, thereby making the power generation system suitable for application scenarios with more power level requirements. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of an application scenario of the power generation system provided in this application;

[0041] Figure 2 This is a schematic diagram of another application scenario of the power generation system provided in this application;

[0042] Figure 3 This is a structural schematic diagram of the power generation system provided in this application;

[0043] Figure 4 This is a schematic diagram showing the location of the photovoltaic junction box provided in this application;

[0044] Figure 5 This is another structural schematic diagram of the power generation system provided in this application;

[0045] Figure 6 This is a control timing diagram of the DC / DC converter provided in this application;

[0046] Figure 7a This is a schematic diagram of the current loop of the DC / DC converter provided in this application;

[0047] Figure 7b This is a schematic diagram of the DC / DC converter provided in this application compensating for the output current difference between two types of photovoltaic cells;

[0048] Figure 8 This is another structural schematic diagram of the power generation system provided in this application;

[0049] Figure 9 This is another structural schematic diagram of the power generation system provided in this application;

[0050] Figure 10 This is another structural schematic diagram of the power generation system provided in this application;

[0051] Figure 11 This is another structural schematic diagram of the power generation system provided in this application;

[0052] Figure 12 This is another structural schematic diagram of the power generation system provided in this application;

[0053] Figure 13 This is another structural schematic diagram of the power generation system provided in this application;

[0054] Figure 14 This is another structural schematic diagram of the power generation system provided in this application;

[0055] Figure 15 This is another structural schematic diagram of the power generation system provided in this application;

[0056] Figure 16 This is another structural schematic diagram of the power generation system provided in this application;

[0057] Figure 17 This is another structural schematic diagram of the power generation system provided in this application;

[0058] Figure 18 This is another structural schematic diagram of the power generation system provided in this application;

[0059] Figure 19 This is another structural schematic diagram of the power generation system provided in this application. Detailed Implementation

[0060] The power generation system and integrated photovoltaic modules provided in this application are applicable to various fields such as photovoltaic power generation, photovoltaic-storage hybrid power generation, new energy smart microgrids, and power transmission and distribution, and are suitable for different application scenarios, such as photovoltaic power supply scenarios, photovoltaic-storage hybrid power supply scenarios, and UPS power supply scenarios. The following explanation uses the photovoltaic power supply scenario as an example.

[0061] See Figure 1 , Figure 1 This is a schematic diagram of an application scenario for the power generation system provided in this application. In a photovoltaic power supply scenario, the power generation system provided in this application is... Figure 1The photovoltaic power generation system shown includes photovoltaic modules 11, ..., photovoltaic modules 1n, DC / DC converters 21, ..., DC / DC converters 2n, and inverters 3, where n is an integer greater than 1. Each photovoltaic module 11 includes a first photovoltaic cell PV111 and a second photovoltaic cell PV112 stacked together with different materials. The first photovoltaic cell PV111 and the second photovoltaic cell PV112 are connected in series between the first output terminal o111 and the second output terminal o112 of the photovoltaic module 11. The connection point of the first photovoltaic cell PV111 and the second photovoltaic cell PV112 is connected to the third output terminal o113 of the photovoltaic module 11. The first input terminal i211 of the DC / DC converter 21 is connected to the first output terminal o111 of the photovoltaic module 11, the second input terminal i212 of the DC / DC converter 21 is connected to the second output terminal o112 of the photovoltaic module 11, and the third input terminal i213 of the DC / DC converter 21 is connected to the third output terminal o113 of the photovoltaic module 11. ... The photovoltaic module 1n includes a first photovoltaic cell PV1n1 and a second photovoltaic cell PV1n2 stacked together with different materials. The first photovoltaic cell PV1n1 and the second photovoltaic cell PV1n2 are connected in series between the first output terminal o1n1 and the second output terminal o1n2 of the photovoltaic module 1n. The connection point of the first photovoltaic cell PV1n1 and the second photovoltaic cell PV1n2 is connected to the third output terminal o1n3 of the photovoltaic module 1n. The first input terminal i2n1 of the DC / DC converter 2n is connected to the first output terminal o1n1 of the photovoltaic module 1n. The second input terminal i2n2 of the DC / DC converter 2n is connected to the second output terminal o1n2 of the photovoltaic module 1n. The third input terminal i2n3 of the DC / DC converter 2n is connected to the third output terminal o1n3 of the photovoltaic module 1n. The output terminals of the DC / DC converter 21, ..., and the output terminals of the DC / DC converter 2n are connected in series to the input terminal of the inverter 3. The output terminal of the inverter 3 is connected to the AC power grid or household appliances.

[0062] After the photovoltaic power generation system starts operating, the first and second photovoltaic cells in n photovoltaic modules absorb solar energy of different wavelengths and convert the absorbed solar energy into electrical energy, which is then output to their respective connected DC / DC converters. Because the materials of the first and second photovoltaic cells in each photovoltaic module are different, their output currents differ, preventing direct series connection. Therefore, each DC / DC converter compensates for the difference in output current between the two types of photovoltaic cells in its connected photovoltaic module, enabling series connection of the two types of photovoltaic cells through the DC / DC converter connected to each photovoltaic module. Simultaneously, the n DC / DC converters also perform DC-DC conversion on the DC power output from their respective connected photovoltaic modules and output the converted DC power to the input of inverter 3. Inverter 3 sequentially boosts and inverts the DC power at its input to obtain AC power that meets the requirements of the AC power grid, thereby powering various types of electrical equipment, including those connected to the AC power grid.

[0063] It is understood that the photovoltaic module provided in this application is a double-junction photovoltaic module, that is, a photovoltaic module using double-junction solar cells. Since the output current of the first photovoltaic cell in each photovoltaic module differs from that of the second photovoltaic cell, the first and second photovoltaic cells in each photovoltaic module cannot be directly connected in series. Therefore, when the two types of photovoltaic cells in each photovoltaic module are connected in series, each DC / DC converter can compensate for the difference in output current between the two types of photovoltaic cells in its connected photovoltaic module, enabling the two types of photovoltaic cells in each photovoltaic module to operate in series through the DC / DC converter. In other words, the outputs of the two types of photovoltaic cells in each photovoltaic module are adapted. Furthermore, since the method of adapting the outputs of the two types of photovoltaic cells in each photovoltaic module through the DC / DC converter does not require special treatment of the photovoltaic cell materials or manufacturing processes, it can accommodate most double-junction photovoltaic modules on the market and save related costs. It also does not change the original output characteristics (i.e., output voltage and output current) of the two types of photovoltaic cells in each photovoltaic module. Therefore, the two types of photovoltaic cells in each photovoltaic module can output according to their respective output characteristics when their photoelectric conversion efficiency is at its highest. Thus, each double-junction photovoltaic module can achieve the highest photoelectric conversion efficiency.

[0064] See Figure 2 , Figure 2 This is a schematic diagram of another application scenario of the power generation system provided in this application. In a photovoltaic power supply scenario, the power generation system provided in this application is... Figure 2The photovoltaic power generation system shown includes photovoltaic modules 11, ..., photovoltaic modules 1n, DC / DC converters 21, ..., DC / DC converters 2n, and inverters 3, where n is an integer greater than 1. Each photovoltaic module 11 includes a first photovoltaic cell PV111 and a second photovoltaic cell PV112 stacked together with different materials. The first output terminal (e.g., positive output terminal) of the first photovoltaic cell PV111 and the first output terminal (e.g., positive output terminal) of the second photovoltaic cell PV112 are both connected to the first output terminal o111 of the photovoltaic module 11. The second output terminal (e.g., negative output terminal) of the first photovoltaic cell PV111 is connected to the second output terminal o112 of the photovoltaic module 11, and the second output terminal (e.g., negative output terminal) of the second photovoltaic cell PV112 is connected to the photovoltaic module. The third output terminal o113 of component 11; the first input terminal i211 of DC / DC converter 21 is connected to the first output terminal o111 of photovoltaic module 11 and the first output terminal o211 of DC / DC converter 21 (e.g., positive output terminal); the second input terminal i212 of DC / DC converter 21 is connected to the second output terminal o112 of photovoltaic module 11; the third input terminal i213 of DC / DC converter 21 is connected to the third output terminal o113 of photovoltaic module 11 and the second output terminal o212 of DC / DC converter 21 (e.g., negative output terminal). ... The photovoltaic module 1n includes a first photovoltaic cell PV1 n1 and a second photovoltaic cell PV1 n2 stacked together and made of different materials. The first output terminal (e.g., positive output terminal) of the first photovoltaic cell PV1 n1 and the first output terminal (e.g., positive output terminal) of the second photovoltaic cell PV1 n2 are both connected to the first output terminal o1 n1 of the photovoltaic module 1n. The second output terminal (e.g., negative output terminal) of the first photovoltaic cell PV1 n1 is connected to the second output terminal o1 n2 of the photovoltaic module 1n. The second output terminal (e.g., negative output terminal) of the second photovoltaic cell PV1 n2 is connected to the third output terminal o1 n3 of the photovoltaic module 1n. The first input terminal i2 n1 of the DC / DC converter 2n is connected to the first output terminal o1 n1 of the photovoltaic module 1n and the first output terminal o2 n1 (e.g., positive output terminal) of the DC / DC converter 2n. The second input terminal i2 n2 of the DC / DC converter 2n is connected to the second output terminal o1 n2 of the photovoltaic module 1n. The third input terminal i2 n3 of the DC / DC converter 2n is connected to the third output terminal o1 n1 of the photovoltaic module 1n. The second output terminal o2n2 of DC / DC converter 2n (e.g., a negative output terminal) is connected in series with the output terminals of DC / DC converter 21, ..., and the output terminals of DC / DC converter 2n. The input terminal of inverter 3 is then connected to the AC power grid or household appliances. Optionally, the first output terminal of the first photovoltaic cell and the first output terminal of the second photovoltaic cell in each photovoltaic module can both be negative output terminals, in which case the second output terminal of each DC / DC converter is a positive output terminal.

[0065] After the photovoltaic power generation system starts operating, the first and second photovoltaic cells in n photovoltaic modules absorb solar energy of different wavelengths and convert the absorbed solar energy into electrical energy, which is then output to their respective connected DC / DC converters. Because the materials of the first and second photovoltaic cells in each photovoltaic module are different, their output voltages differ, preventing them from being directly connected in parallel. Therefore, each DC / DC converter converts the output voltage of the first photovoltaic cell in its connected photovoltaic module to the output voltage of the second photovoltaic cell, enabling parallel connection of the two types of photovoltaic cells in each module through the DC / DC converter connected to each module. Subsequently, the n DC / DC converters output the converted DC power to the input of inverter 3. Inverter 3 sequentially boosts and inverts the DC power at its input to obtain AC power that meets the requirements of the AC power grid, thereby supplying power to various types of electrical equipment, including those connected to the AC power grid.

[0066] It is understood that the photovoltaic module provided in this application is a dual-junction photovoltaic module. Since the output voltage of the first photovoltaic cell in each photovoltaic module is different from that of the second photovoltaic cell, the first photovoltaic cell and the second photovoltaic cell in each photovoltaic module cannot be directly connected in parallel. Therefore, when the first photovoltaic cell in each photovoltaic module is connected in parallel with the second photovoltaic cell through a DC / DC converter, each DC / DC converter can convert the output voltage of the first photovoltaic cell in its connected photovoltaic module into the output voltage of the second photovoltaic cell, so that the output voltage of the first photovoltaic cell in each photovoltaic module after being converted by the DC / DC converter is the same as the output voltage of the second photovoltaic cell. This allows the two types of photovoltaic cells in each photovoltaic module to work in parallel through the DC / DC converter. In other words, it makes the outputs of the two types of photovoltaic cells in each photovoltaic module compatible. Furthermore, since the output of the two photovoltaic cells in each photovoltaic module is adapted through a DC / DC converter, there is no special requirement for the photovoltaic cell materials or manufacturing process. Therefore, it can accommodate most dual-junction photovoltaic modules on the market and save related costs. It also does not change the original output characteristics of the two photovoltaic cells in each photovoltaic module. As a result, the two photovoltaic cells in each photovoltaic module can output according to their respective output characteristics when their photoelectric conversion efficiency is at its highest. Therefore, each dual-junction photovoltaic module can achieve the highest photoelectric conversion efficiency.

[0067] In summary, the photovoltaic module provided in this application can not only achieve series or parallel connection of the two types of photovoltaic cells inside through a DC / DC converter, that is, adapt the output of the two types of photovoltaic cells, but also maximize the photoelectric conversion efficiency of the two types of photovoltaic cells, thereby increasing the power generation of the power generation system.

[0068] The above are merely examples of application scenarios for the power generation system provided in this application, and are not exhaustive. This application does not limit the application scenarios.

[0069] The following is combined with Figures 3 to 19 The working principle of the integrated photovoltaic module and power generation system provided in this application is illustrated by example.

[0070] See Figure 3 , Figure 3 This is a structural schematic diagram of the power generation system provided in this application. For example... Figure 3As shown, the power generation system includes integrated photovoltaic modules 11, ..., and integrated photovoltaic modules 1n, where n is a positive integer. The integrated photovoltaic module 11 includes a DC / DC converter 21 and a first photovoltaic cell PV111 and a second photovoltaic cell PV112 stacked with different materials. The first photovoltaic cell PV111 and the second photovoltaic cell PV112 are connected in series between the first input terminal i211 (positive input terminal) and the second input terminal i212 (negative input terminal) of the DC / DC converter 21. The connection between the first photovoltaic cell PV111 and the second photovoltaic cell PV112 is connected to the third input terminal i213 of the DC / DC converter 21. The output terminal of the DC / DC converter 21 is connected to the output terminal of the integrated photovoltaic module 11. Specifically, the first output terminal o211 (positive output terminal) of the DC / DC converter 21 is connected to the first output terminal o111 (positive output terminal) of the integrated photovoltaic module 11, and the second output terminal o212 (negative output terminal) of the DC / DC converter 21 is connected to the second output terminal o112 (negative output terminal) of the integrated photovoltaic module 11. ... The integrated photovoltaic module 1n includes a DC / DC converter 2n and a first photovoltaic cell PV1 n1 and a second photovoltaic cell PV1 n2 stacked with different materials. The first photovoltaic cell PV1 n1 and the second photovoltaic cell PV1 n2 are connected in series between the first input terminal i2n1 (i.e., the positive input terminal) and the second input terminal i2n2 (i.e., the negative input terminal) of the DC / DC converter 2n. The connection between the first photovoltaic cell PV1 n1 and the second photovoltaic cell PV1 n2 is connected to the third input terminal i2n3 of the DC / DC converter 2n. The output terminal of the DC / DC converter 2n is connected to the output terminal of the integrated photovoltaic module 1n. Specifically, the first output terminal o2n1 (i.e., the positive output terminal) of the DC / DC converter 2n is connected to the first output terminal o1 n1 (i.e., the positive output terminal) of the integrated photovoltaic module 1n, and the second output terminal o2n2 (i.e., the negative output terminal) of the DC / DC converter 2n is connected to the second output terminal o1 n2 (i.e., the negative output terminal) of the integrated photovoltaic module 1n. Optionally, the power generation system also includes an inverter 3, with the output terminals of integrated photovoltaic modules 11, ..., and the output terminals of integrated photovoltaic modules 1n connected in series on the two input terminals of the inverter 3, and the output terminal of the inverter 3 being used to connect to the power grid.

[0071] The n integrated photovoltaic modules provided in this application are dual-junction photovoltaic modules. Specifically, the first and second photovoltaic cells in each integrated photovoltaic module can be understood as a wide-bandgap cell and a narrow-bandgap cell, with the wide-bandgap cell located above the narrow-bandgap cell. The first photovoltaic cell in this application can be either a wide-bandgap cell or a narrow-bandgap cell; this application does not limit this. The wide-bandgap cell and the narrow-bandgap cell are made of semiconductor materials with different bandgap characteristics, respectively performing photoelectric conversion on sunlight of different wavelengths. For example, the manufacturing materials for the wide-bandgap cell include perovskite, and the manufacturing materials for the narrow-bandgap cell include crystalline silicon, copper indium gallium selenide, etc. Furthermore, each integrated photovoltaic module has two output terminals. Specifically, each integrated photovoltaic module has only two output terminals: a positive output terminal and a negative output terminal. This allows the integrated photovoltaic modules in this embodiment to be connected in series or parallel like traditional single-junction photovoltaic modules. Compared to dual-junction photovoltaic modules with four output terminals, this effectively saves on wiring costs between the integrated photovoltaic modules and other devices (such as inverters). Furthermore, in practical applications, each integrated photovoltaic module is also equipped with a photovoltaic junction box. The DC / DC converter in each integrated photovoltaic module can be installed inside its respective photovoltaic junction box, and the junction box is installed on the back of its respective integrated photovoltaic module, such as... Figure 4 The location diagram shown illustrates this. Therefore, it does not increase the size of the integrated photovoltaic module, which is beneficial for its miniaturization design. Furthermore, the DC / DC converter in the integrated photovoltaic module also functions as a photovoltaic optimizer, such as performing Maximum Power Point Tracking (MPPT) on the two types of photovoltaic cells in the integrated photovoltaic module to maximize the output power of the integrated photovoltaic module. In this case, the power generation system does not need to additionally set up a photovoltaic optimizer between the integrated photovoltaic module and inverter 3, effectively saving the cost of the power generation system. Optionally, the DC / DC converter in the integrated photovoltaic module can also perform different functions than the photovoltaic optimizer. For example, if the DC / DC converter in the integrated photovoltaic module does not have MPPT functionality, a photovoltaic optimizer can still be set up between the integrated photovoltaic module and inverter 3 to increase the power generation of the power generation system.

[0072] Because the materials of the first and second photovoltaic cells in each integrated photovoltaic module are different, their output currents also differ, preventing them from being directly connected in series. Therefore, the DC / DC converter in each integrated photovoltaic module compensates for the difference in output current between the two types of photovoltaic cells, enabling them to operate in series through the connected DC / DC converter.

[0073] because Figure 3 The circuit structure and operating principle of each DC / DC converter in the power generation system shown are the same. Therefore, for ease of description, the following will be combined with... Figures 5 to 7b The following is a detailed introduction using the DC / DC converter 21 as an example.

[0074] See Figure 5 , Figure 5 This is another structural schematic diagram of the power generation system provided in this application. For example... Figure 5 As shown, the DC / DC converter 21 includes a first switch Q1, a second switch Q2, an inductor L1, and a controller 211. The first switch Q1 and the second switch Q2 are connected in series between the first input terminal i211 and the second input terminal i212 of the DC / DC converter 21. The inductor L1 is connected between the third input terminal i213 of the DC / DC converter 21 and the connection point of the first switch Q1 and the second switch Q2. The first input terminal i211 of the DC / DC converter 21 is connected to the first output terminal o211 of the DC / DC converter 21, and the second input terminal i212 of the DC / DC converter 21 is connected to the second output terminal o212 of the DC / DC converter 21. Optionally, the DC / DC converter 21 also includes a diode D1 and an output capacitor C1. The cathode of the diode D1 is connected to the first output terminal o211 of the DC / DC converter 21, and the anode of the diode D1 is connected to the second output terminal o212 of the DC / DC converter 21. The output capacitor C1 is connected between the first output terminal o211 and the second output terminal o212 of the DC / DC converter 21.

[0075] After the DC / DC converter 21 starts working, the controller 211 controls the first switch Q1 and the second switch Q2 to conduct complementaryly, so that the DC / DC converter 21 compensates for the difference between the output current of the first photovoltaic cell PV111 and the output current of the second photovoltaic cell PV112.

[0076] Specifically, if the materials of the first photovoltaic cell PV111 and the second photovoltaic cell PV112 are different, causing the output current of the first photovoltaic cell PV111 to be greater than the output current of the second photovoltaic cell PV112, then the controller 211 controls the first switch Q1 and the second switch Q2 to conduct complementaryly, and the duty cycle of the first switch Q1 is greater than the duty cycle of the second switch Q2. Conversely, if the materials of the first photovoltaic cell PV111 and the second photovoltaic cell PV112 are different, causing the output current of the first photovoltaic cell PV111 to be less than the output current of the second photovoltaic cell PV112, then the controller 211 controls the first switch Q1 and the second switch Q2 to conduct complementaryly, and the duty cycle of the first switch Q1 is less than the duty cycle of the second switch Q2.

[0077] To facilitate understanding, the following explains the specific principle behind the relationship between the duty cycles of the first switch Q1 and the second switch Q2, which depends on the relationship between the output currents of the first photovoltaic cell PV111 and the second photovoltaic cell PV112: Assume the on-time of the first switch Q1 is T1, and the on-time of the second switch Q2 is T2. The sum of T1 and T2 is the switching period T of either the first switch Q1 or the second switch Q2. Then, when the first switch Q1 is on, the change in current ΔI in inductor L1 and the induced voltage U1 satisfy the following relationship: ΔI = U1 * T1 / L1; when the second switch Q2 is on, the change in current ΔI' in inductor L1 and the induced voltage U2 satisfy the following relationship: ΔI' = U2 * T2 / L1. Since ΔI = ΔI', we can obtain U1 / U2 = T2 / T1. Since the first photovoltaic cell PV111 and the second photovoltaic cell PV112 are of the high-current, low-voltage output type and the low-current, high-voltage output type, respectively, and the output power of each photovoltaic cell is constant when operating stably, it can be concluded that the smaller the output current of the photovoltaic cell, the larger the output voltage of the photovoltaic cell. Furthermore, since the output voltage of the photovoltaic cell when the first switch Q1 or the second switch Q2 is turned on can be understood as the inductance voltage U1 or U2 of the inductor L1, it can be concluded that the larger the output voltage of the photovoltaic cell, the shorter the conduction time of the switch connected to the photovoltaic cell, that is, the smaller the duty cycle of the switch connected to the photovoltaic cell. In summary, the smaller the output current of the photovoltaic cell, the smaller the duty cycle of the switch connected to the photovoltaic cell; the larger the output current of the photovoltaic cell, the larger the duty cycle of the switch connected to the photovoltaic cell.

[0078] To better understand, the following will be combined with... Figure 6 , Figure 7a and Figure 7b Taking the output current of the first photovoltaic cell PV111 as 1A and the output current of the second photovoltaic cell PV112 as 10A as an example, the specific implementation process of the controller 211 controlling the DC / DC converter 21 to compensate for the difference between the output currents of the two photovoltaic cells is introduced.

[0079] like Figure 6 As shown, during the time period from t1 to t2 (the second duration T2), the controller 211 outputs a low-level signal to the first switch Q1 and a high-level signal to the second switch Q2, controlling the first switch Q1 to be in the off state and the second switch Q2 to be in the on state. This allows the current flowing from the positive output terminal of the second photovoltaic cell PV112 to flow sequentially through the inductor L1 and the second switch Q2, and then flow back to the negative output terminal of the second photovoltaic cell PV112, forming a first current loop (e.g., ...). Figure 7a The clockwise current loop 1 is shown. Correspondingly, the current I in inductor L1 is... L1It increases continuously as the on-time of the second switch Q2 increases.

[0080] During the time period from t2 to t3 (the first duration T1), the controller 211 outputs a high-level signal to the first switch Q1 and a low-level signal to the second switch Q2 to control the first switch Q1 to be in the on state and the second switch Q2 to be in the off state. Because the first switch Q1 is on, the direction of the electromotive force applied to the inductor L1 is opposite to the direction of the electromotive force applied to the inductor L1 during the second duration T2. ​​Furthermore, since the current direction in the inductor cannot change abruptly, the current direction in the inductor L1 is... Figure 7a The dashed line indicates the direction, therefore, the current I in inductor L1 L1 The value decreases continuously as the on-time of the first switch Q1 increases. Where T1 < T2, and T1 + T2 = T.

[0081] based on Figure 6 The periodic control method shown can be used to obtain the current I on inductor L1. L1 The current is 9A, and the current direction on inductor L1 flows from node b (the connection between the first photovoltaic cell PV111 and the second photovoltaic cell PV112) to node a (the connection between the first switching transistor Q1 and the second switching transistor Q2 of the first photovoltaic cell). This ensures that node b satisfies Kirchhoff's current law (the sum of the currents flowing into node b equals the sum of the currents flowing out of node b). In other words, the DC / DC converter 21 compensates for the difference between the output current of the first photovoltaic cell PV111 and the output current of the second photovoltaic cell PV112. In other words, the DC / DC converter 21 compensates for the difference between the output current of the first photovoltaic cell PV111 and the output current of the second photovoltaic cell PV112, which can be understood as ensuring that the current in inductor L1, the output current of the first photovoltaic cell PV111, and the output current of the second photovoltaic cell PV112 satisfy Kirchhoff's current law at node b. Figure 7b For example, since the output current (1A) of the first photovoltaic cell PV111 is the current flowing out of node b, and the output current (10A) of the second photovoltaic cell PV112 is the current flowing into node b, and since the sum of the currents flowing into node b is equal to the sum of the currents flowing out of node b, the DC / DC converter 21 can compensate for the difference between the output current (1A) of the first photovoltaic cell PV111 and the output current (10A) of the second photovoltaic cell PV112. Specifically, the current in inductor L1 is made to be equal to the absolute value of the difference between the output current (1A) of the first photovoltaic cell PV111 and the output current (9A) of the second photovoltaic cell PV112, and the direction of the current in inductor L1 is the direction of flowing out of node b.

[0082] In this application, because the output current of the first photovoltaic cell in each integrated photovoltaic module is different from that of the second photovoltaic cell, the first and second photovoltaic cells in each integrated photovoltaic module cannot be directly connected in series. Therefore, when the two types of photovoltaic cells in each integrated photovoltaic module are connected in series, the DC / DC converter in each integrated photovoltaic module can compensate for the difference between the output currents of the two types of photovoltaic cells in each integrated photovoltaic module, so that the two types of photovoltaic cells in each integrated photovoltaic module can operate in series through the DC / DC converter. In other words, the outputs of the two types of photovoltaic cells in each integrated photovoltaic module are adapted. Furthermore, since the method of adapting the outputs of the two types of photovoltaic cells in each integrated photovoltaic module through the DC / DC converter does not require special treatment of the photovoltaic cell materials or manufacturing processes, it can accommodate most dual-junction photovoltaic modules on the market and save related costs. Moreover, it does not change the original output characteristics of the two types of photovoltaic cells in each integrated photovoltaic module. Therefore, the two types of photovoltaic cells in each integrated photovoltaic module can output according to their respective output characteristics when their photoelectric conversion efficiency is at its highest. Thus, each integrated photovoltaic module can achieve the highest photoelectric conversion efficiency, thereby increasing the power generation of the power generation system.

[0083] See Figure 8 , Figure 8 This is another structural schematic diagram of the power generation system provided in this application. For example... Figure 8As shown, the power generation system includes integrated photovoltaic modules 11, ..., and integrated photovoltaic modules 1n, where n is a positive integer. The integrated photovoltaic module 11 includes a DC / DC converter 21, and a first photovoltaic cell PV111 and a second photovoltaic cell PV112 stacked with different materials. The first output terminal of the first photovoltaic cell PV111 and the first output terminal of the second photovoltaic cell PV112 are both connected to the first input terminal i211 of the DC / DC converter 21. The second output terminal of the first photovoltaic cell PV111 is connected to the second input terminal i212 of the DC / DC converter 21, and the second output terminal of the second photovoltaic cell PV112 is connected to the third input terminal i213 of the DC / DC converter 21. The first output terminal o211 of the DC / DC converter 21 is connected to the first input terminal i211 of the DC / DC converter 21 and the first output terminal o111 of the integrated photovoltaic module 11. The second output terminal o212 of the DC / DC converter 21 is connected to the third input terminal i213 of the DC / DC converter 21 and the second output terminal o112 of the integrated photovoltaic module 11. The polarity of the first output terminal of the first photovoltaic cell PV111 is the same as the polarity of the first output terminal of the second photovoltaic cell PV112, and opposite to the polarity of the second output terminal o212 of the DC / DC converter 21. ... The integrated photovoltaic module 1n includes a DC / DC converter 2n, and a first photovoltaic cell PV1n1 and a second photovoltaic cell PV1n2 stacked with different materials. The first output terminal of the first photovoltaic cell PV1n1 and the first output terminal of the second photovoltaic cell PV1n2 are both connected to the first input terminal i2n1 of the DC / DC converter 2n. The second output terminal of the first photovoltaic cell PV1n1 is connected to the second input terminal i2n2 of the DC / DC converter 2n, and the second output terminal of the second photovoltaic cell PV1n2 is connected to the third input terminal i2n3 of the DC / DC converter 2n. The first output terminal o2n1 of the C / DC converter 2n is connected to the first input terminal i2n1 of the DC / DC converter 2n and the first output terminal o111 of the integrated photovoltaic module 1n. The second output terminal o2n2 of the DC / DC converter 2n is connected to the third input terminal i2n3 of the DC / DC converter 2n and the second output terminal o1n2 of the integrated photovoltaic module 1n. The polarity of the first output terminal of the first photovoltaic cell PV1n1 is the same as the polarity of the first output terminal of the second photovoltaic cell PV1n2, and opposite to the polarity of the second output terminal o2n2 of the DC / DC converter 2n. Optionally, the power generation system includes an inverter 3. The output terminals of the DC / DC converter 21, ..., and the output terminals of the DC / DC converter 2n are connected in series to the input terminal of the inverter 3. The output terminal of the inverter 3 is connected to the power grid or a load.

[0084] The n integrated photovoltaic modules provided in this application are dual-junction photovoltaic modules. Specifically, the first and second photovoltaic cells in each integrated photovoltaic module can be understood as a wide-bandgap cell and a narrow-bandgap cell, with the wide-bandgap cell located above the narrow-bandgap cell. The first photovoltaic cell in this application can be either a wide-bandgap cell or a narrow-bandgap cell; this application does not limit this. Furthermore, each integrated photovoltaic module has only two output terminals: a positive output terminal and a negative output terminal. This allows the integrated photovoltaic modules in this embodiment to be connected in series or parallel like traditional single-junction photovoltaic modules. Compared to dual-junction photovoltaic modules with four output terminals, this effectively saves on wiring costs between the integrated photovoltaic modules and other devices. Moreover, in practical applications, each integrated photovoltaic module is also equipped with a photovoltaic junction box. The DC / DC converter in each integrated photovoltaic module can be housed within its respective junction box, and the junction box is installed on the back of the integrated photovoltaic module. Therefore, this does not increase the size of the integrated photovoltaic module, which is beneficial for miniaturized design. Furthermore, the DC / DC converter in the integrated photovoltaic module also functions as a photovoltaic optimizer, such as MPPT (Multi-Performance Testing). This eliminates the need for an additional photovoltaic optimizer between the integrated photovoltaic module and inverter 3, effectively saving on system costs. Optionally, the DC / DC converter in the integrated photovoltaic module may perform a different function than the photovoltaic optimizer. For example, if the DC / DC converter in the integrated photovoltaic module does not have MPPT, a photovoltaic optimizer can still be installed between the integrated photovoltaic module and inverter 3 to increase the power generation of the system.

[0085] Because the materials of the first and second photovoltaic cells in each integrated photovoltaic module are different, their output voltages differ, preventing them from being directly connected in parallel. Therefore, each integrated photovoltaic module uses a DC / DC converter to convert the output voltage of the first photovoltaic cell to that of the second, ensuring that the output voltage of the first photovoltaic cell after conversion is the same as that of the second. This allows the two types of photovoltaic cells in each integrated photovoltaic module to operate in parallel via the DC / DC converter.

[0086] Furthermore, since the first output terminals of the two types of photovoltaic cells in each integrated photovoltaic module include both positive and negative polarities, and since the circuit structure and operating principle of each DC / DC converter in the power generation system are identical, for ease of description, the following will combine... Figures 9 to 12 Following the sequence of connecting the two types of photovoltaic cells with the common positive electrode and then with the common negative electrode, and taking DC / DC converter 21 as an example, the following steps are performed: Figure 8 The power generation system shown is described in detail.

[0087] In one embodiment, the polarity of the first output terminal of the first photovoltaic cell and the first output terminal of the second photovoltaic cell in each integrated photovoltaic module are both positive, and the polarity of the second output terminal of each DC / DC converter is negative.

[0088] Specifically, such as Figure 9 As shown, for the integrated photovoltaic module 11: when the first photovoltaic cell PV111 and the second photovoltaic cell PV112 are connected with the same positive electrode, the first output terminal of the first photovoltaic cell PV111, the first output terminal of the second photovoltaic cell PV112, the first output terminal o111 of the integrated photovoltaic module 11, and the first output terminal of the DC / DC converter 21 are all positive output terminals. The second output terminals of the first photovoltaic cell PV111, the second output terminal of the second photovoltaic cell PV112, the second output terminal o112 of the integrated photovoltaic module 11, and the second output terminal o212 of the DC / DC converter 21 are all negative output terminals. The first input terminal i211 of the DC / DC converter 21 is a positive input terminal, and the second input terminal i212 of the DC / DC converter 21 is a negative input terminal. Similarly, the polarity of the input and output terminals of the two types of photovoltaic cells and the DC / DC converter of other integrated photovoltaic modules in the power generation system can be obtained, which will not be described in detail here.

[0089] Furthermore, the DC / DC converter 21 includes a DC / DC conversion circuit and a controller 211. Exemplarily, the DC / DC conversion circuit is a negative BUCK circuit 212, which is an inverted version of the BUCK circuit, including a first switch Q1, a second switch Q2, an inductor L1, and an output capacitor C1. The first switch Q1 and the second switch Q2 are connected in series between the positive and negative input terminals of the DC / DC converter 21. The inductor L1 is connected between the connection point of the first switch Q1 and the second switch Q2 and the negative output terminal of the DC / DC converter 21. The output capacitor C1 is connected between the positive and negative output terminals of the DC / DC converter 21. Optionally, the negative BUCK circuit 212 further includes a diode D1 and an input capacitor C2. The cathode of the diode D1 is connected to the positive output terminal of the DC / DC converter 21, and the anode of the diode D1 is connected to the negative output terminal of the DC / DC converter 21. The input capacitor C2 is connected between the positive and negative input terminals of the DC / DC converter 21.

[0090] After the DC / DC converter 21 starts working, the controller 211 can control the switching action of the first switch Q1 and the second switch Q2 in the negative BUCK circuit 212 to reduce the output voltage of the first photovoltaic cell PV111 to obtain the same voltage value as the output voltage of the second photovoltaic cell PV112, thereby enabling the first photovoltaic cell PV111 and the second photovoltaic cell PV112 to be connected in parallel through the DC / DC converter 21.

[0091] Optionally, the DC / DC conversion circuit in DC / DC converter 21 can also be a negative boost circuit; please refer to [link to relevant documentation] for details. Figure 10 .like Figure 10 As shown, the negative BOOST circuit 212 is an inverted BOOST circuit, including a first switch Q1, a second switch Q2, an inductor L1, and an output capacitor C1. The first switch Q1 and the second switch Q2 are connected in series between the positive and negative output terminals of the DC / DC converter 21. The inductor L1 is connected between the junction of the first switch Q1 and the second switch Q2 and the negative input terminal of the DC / DC converter 21. The output capacitor C1 is connected between the positive and negative output terminals of the DC / DC converter 21. Optionally, the negative BOOST circuit 212 also includes a diode D1, with the cathode of diode D1 connected to the positive output terminal of the DC / DC converter 21 and the anode of diode D1 connected to the negative output terminal of the DC / DC converter 21.

[0092] After the DC / DC converter 21 starts working, the controller 211 can control the switching action of the first switch Q1 and the second switch Q2 in the negative BOOST circuit 212 to boost the output voltage of the first photovoltaic cell PV111 to obtain the same voltage value as the output voltage of the second photovoltaic cell PV112, thereby enabling the first photovoltaic cell PV111 and the second photovoltaic cell PV112 to be connected in parallel through the DC / DC converter 21.

[0093] Understandably, because the output voltages of the first and second photovoltaic cells in each integrated photovoltaic module differ, they cannot be directly connected in parallel. Therefore, when both types of photovoltaic cells in each integrated photovoltaic module are connected with a common positive terminal, a connection is made by linking the positive input terminal of the DC / DC converter to the positive output terminals of both photovoltaic cells and the positive output terminal of the DC / DC converter, and connecting the negative output terminal of the second photovoltaic cell to the negative output terminal of the DC / DC converter. This allows the first and second photovoltaic cells to be connected in parallel via the DC / DC converter. Based on this, each integrated photovoltaic module converts the output voltage of the first photovoltaic cell to the output voltage of the second photovoltaic cell through the DC / DC converter, ensuring that the output voltage of the first photovoltaic cell after conversion is the same as that of the second photovoltaic cell. This allows the two types of photovoltaic cells in each integrated photovoltaic module to operate in parallel via the DC / DC converter; in other words, it enables the outputs of the two types of photovoltaic cells in each integrated photovoltaic module to be compatible. Furthermore, since the output of the two photovoltaic cells in each integrated photovoltaic module is adapted through a DC / DC converter, there is no special requirement for the photovoltaic cell materials or manufacturing process. Therefore, it can be compatible with most dual-junction photovoltaic modules on the market and save related costs. It also does not change the original output characteristics of the two photovoltaic cells in each integrated photovoltaic module. As a result, the two photovoltaic cells in each integrated photovoltaic module can output according to their respective output characteristics when their photoelectric conversion efficiency is at its highest. Therefore, each integrated photovoltaic module can achieve the highest photoelectric conversion efficiency, thereby increasing the power generation of the power generation system.

[0094] In another embodiment, the polarity of the first output terminal of the first photovoltaic cell and the first output terminal of the second photovoltaic cell in each integrated photovoltaic module are both negative, and the polarity of the second output terminal of each DC / DC converter is positive.

[0095] Specifically, such as Figure 11As shown, for the integrated photovoltaic module 11: when the first photovoltaic cell PV111 and the second photovoltaic cell PV112 are connected with a common negative terminal, the first output terminal of the first photovoltaic cell PV111, the first output terminal of the second photovoltaic cell PV112, the first output terminal o111 of the integrated photovoltaic module 11, and the first output terminal of the DC / DC converter 21 are all negative output terminals. The second output terminals of the first photovoltaic cell PV111, the second output terminal of the second photovoltaic cell PV112, the second output terminal o112 of the integrated photovoltaic module 11, and the second output terminal o212 of the DC / DC converter 21 are all positive output terminals. The first input terminal i211 of the DC / DC converter 21 is a negative input terminal, and the second input terminal i212 of the DC / DC converter 21 is a positive input terminal. Similarly, the polarity of the input and output terminals of the two types of photovoltaic cells and the DC / DC converter of other integrated photovoltaic modules in the power generation system can be obtained, which will not be described in detail here.

[0096] Furthermore, the DC / DC converter 21 includes a DC / DC conversion circuit and a controller 211. Exemplarily, the DC / DC conversion circuit is a BUCK circuit 212, including a first switch Q1, a second switch Q2, an inductor L1, and an output capacitor C1. The first switch Q1 and the second switch Q2 are connected in series between the positive and negative input terminals of the DC / DC converter 21. The inductor L1 is connected between the connection point of the first switch Q1 and the second switch Q2 and the positive output terminal of the DC / DC converter 21. The output capacitor C1 is connected between the positive and negative output terminals of the DC / DC converter 21. Optionally, the BUCK circuit 212 also includes a diode D1 and an input capacitor C2. The cathode of the diode D1 is connected to the positive output terminal of the DC / DC converter 21, and the anode of the diode D1 is connected to the negative output terminal of the DC / DC converter 21. The input capacitor C2 is connected between the positive and negative input terminals of the DC / DC converter 21.

[0097] After the DC / DC converter 21 starts working, the controller 211 can control the switching action of the first switch Q1 and the second switch Q2 in the negative BUCK circuit 212 to reduce the output voltage of the first photovoltaic cell PV111 to obtain the same voltage value as the output voltage of the second photovoltaic cell PV112, thereby enabling the first photovoltaic cell PV111 and the second photovoltaic cell PV112 to be connected in parallel through the DC / DC converter 21.

[0098] Optionally, the DC / DC conversion circuit in DC / DC converter 21 can also be a BOOST circuit; please refer to [link to details]. Figure 12 .like Figure 12As shown, the BOOST circuit 212 includes a first switching transistor Q1, a second switching transistor Q2, an inductor L1, and an output capacitor C1. The second switching transistor Q2 and the first switching transistor Q1 are connected in series between the positive and negative output terminals of the DC / DC converter 21. The inductor L1 is connected between the junction of the first and second switching transistors Q1 and the positive input terminal of the DC / DC converter 21. The output capacitor C1 is connected between the positive and negative output terminals of the DC / DC converter 21. Optionally, the BOOST circuit 212 also includes a diode D1, with the cathode of diode D1 connected to the positive output terminal of the DC / DC converter 21 and the anode of diode D1 connected to the negative output terminal of the DC / DC converter 21.

[0099] After the DC / DC converter 21 starts working, the controller 211 can control the switching action of the first switch Q1 and the second switch Q2 in the BOOST circuit 212 to boost the output voltage of the first photovoltaic cell PV111 to obtain the same voltage value as the output voltage of the second photovoltaic cell PV112, thereby enabling the first photovoltaic cell PV111 and the second photovoltaic cell PV112 to be connected in parallel through the DC / DC converter 21.

[0100] Understandably, because the output voltages of the first and second photovoltaic cells in each integrated photovoltaic module differ, they cannot be directly connected in parallel. Therefore, when both types of photovoltaic cells in each integrated photovoltaic module are connected with a common negative terminal, a connection is made by linking the negative input terminal of the DC / DC converter to the negative output terminals of both photovoltaic cells and the negative output terminal of the DC / DC converter, and connecting the positive output terminal of the second photovoltaic cell to the positive output terminal of the DC / DC converter. This allows the first photovoltaic cell to be connected in parallel with the second photovoltaic cell through the DC / DC converter. Based on this, each integrated photovoltaic module converts the output voltage of the first photovoltaic cell to the output voltage of the second photovoltaic cell through the DC / DC converter, ensuring that the output voltage of the first photovoltaic cell in each integrated photovoltaic module after conversion is the same as the output voltage of the second photovoltaic cell. This allows the two types of photovoltaic cells in each integrated photovoltaic module to operate in parallel through the DC / DC converter; in other words, it enables the outputs of the two types of photovoltaic cells in each integrated photovoltaic module to be compatible. Furthermore, since the output of the two photovoltaic cells in each integrated photovoltaic module is adapted through a DC / DC converter, there is no special requirement for the photovoltaic cell materials or manufacturing process. Therefore, it can be compatible with most dual-junction photovoltaic modules on the market and save related costs. It also does not change the original output characteristics of the two photovoltaic cells in each integrated photovoltaic module. As a result, the two photovoltaic cells in each integrated photovoltaic module can output according to their respective output characteristics when their photoelectric conversion efficiency is at its highest. Therefore, each integrated photovoltaic module can achieve the highest photoelectric conversion efficiency, thereby increasing the power generation of the power generation system.

[0101] In this application, since the output voltage of the first photovoltaic cell in each integrated photovoltaic module is different from that of the second photovoltaic cell, the first and second photovoltaic cells in each integrated photovoltaic module cannot be directly connected in parallel. Therefore, when the first photovoltaic cell in each integrated photovoltaic module is connected in parallel with the second photovoltaic cell through a DC / DC converter, each integrated photovoltaic module can convert the output voltage of the first photovoltaic cell to the output voltage of the second photovoltaic cell through the DC / DC converter. This makes the output voltage of the first photovoltaic cell in each integrated photovoltaic module after conversion by the DC / DC converter the same as the output voltage of the second photovoltaic cell. Thus, the two types of photovoltaic cells in each integrated photovoltaic module can work in parallel through the DC / DC converter. In other words, the outputs of the two types of photovoltaic cells in each integrated photovoltaic module are adapted. Furthermore, because the DC / DC converter adapts the outputs of the two photovoltaic cells in each integrated photovoltaic module, it does not require special treatment of the photovoltaic cell materials or manufacturing processes. Therefore, it can accommodate most dual-junction photovoltaic modules on the market while saving related costs, and it does not change the original output characteristics of the two photovoltaic cells in each integrated photovoltaic module. Thus, the two photovoltaic cells in each integrated photovoltaic module can output according to their respective output characteristics at their highest photoelectric conversion efficiency. Therefore, each integrated photovoltaic module can achieve the highest photoelectric conversion efficiency, thereby increasing the power generation of the power generation system. In addition, the parallel connection of the two photovoltaic cells in each integrated photovoltaic module via the DC / DC converter can be either a common positive terminal connection or a common negative terminal connection, allowing for diverse structures of integrated photovoltaic modules and thus increasing the structural diversity of the power generation system.

[0102] See Figure 13 , Figure 13 This is another structural schematic diagram of the power generation system provided in this application. For example... Figure 13 As shown, with Figure 3 Compared to the power generation system shown, Figure 13 The photovoltaic modules shown are Figure 3 The integrated photovoltaic modules shown are different: Figure 3 The integrated photovoltaic module shown includes a DC / DC converter, while Figure 13 The photovoltaic modules shown do not include a DC / DC converter. Specifically, Figure 13 The power generation system shown includes photovoltaic modules 11, ..., photovoltaic modules 1n, DC / DC converters 21, ..., and DC / DC converters 2n, where n is a positive integer. Optionally, the power generation system also includes an inverter 3. For details on the circuit structures of the photovoltaic modules, DC / DC converters, and inverters, and their interconnections, please refer to [link to relevant documentation]. Figure 1 The description of the corresponding part of the photovoltaic power generation system shown is not repeated here.

[0103] The n photovoltaic modules provided in this application are dual-junction photovoltaic modules. Furthermore, each DC / DC converter has only two output terminals: a positive output terminal and a negative output terminal. This allows the dual-junction photovoltaic modules configured with DC / DC converters to be connected in series or parallel, just like traditional single-junction photovoltaic modules. Compared to dual-junction photovoltaic modules with four output terminals, this effectively saves on wiring costs between the photovoltaic modules and other equipment.

[0104] Because the materials of the first and second photovoltaic cells in each photovoltaic module are different, their output currents also differ, preventing them from being directly connected in series. Therefore, each DC / DC converter in the power generation system compensates for the difference in output current between the two types of photovoltaic cells in its connected photovoltaic module, enabling the two types of photovoltaic cells in each module to operate in series through the connected DC / DC converter.

[0105] in, Figure 13 The circuit structure of the DC / DC converter shown can be found in [reference needed]. Figure 14 The DC / DC converter shown is described below. The circuit structure and operating principle of all DC / DC converters in the power generation system are the same; the following description uses DC / DC converter 21 as an example.

[0106] After the DC / DC converter 21 starts working, the controller 211 controls the first switch Q1 and the second switch Q2 to conduct complementaryly, so that the DC / DC converter 21 compensates for the difference between the output current of the first photovoltaic cell PV111 and the output current of the second photovoltaic cell PV112.

[0107] Specifically, if the materials of the first photovoltaic cell PV111 and the second photovoltaic cell PV112 are different, causing the output current of the first photovoltaic cell PV111 to be greater than the output current of the second photovoltaic cell PV112, then the controller 211 controls the first switch Q1 and the second switch Q2 to conduct complementaryly, and the duty cycle of the first switch Q1 is greater than the duty cycle of the second switch Q2. Conversely, if the materials of the first photovoltaic cell PV111 and the second photovoltaic cell PV112 are different, causing the output current of the first photovoltaic cell PV111 to be less than the output current of the second photovoltaic cell PV112, then the controller 211 controls the first switch Q1 and the second switch Q2 to conduct complementaryly, and the duty cycle of the first switch Q1 is less than the duty cycle of the second switch Q2. For a detailed description of this part, please refer to [link to relevant documentation]. Figures 5 to 7b The descriptions of the corresponding parts in the illustrated embodiments will not be elaborated here.

[0108] In this application, because the output current of the first photovoltaic cell in each photovoltaic module is different from that of the second photovoltaic cell, the first and second photovoltaic cells in each photovoltaic module cannot be directly connected in series. Therefore, when the two types of photovoltaic cells in each photovoltaic module are connected in series, each DC / DC converter can compensate for the difference in output current between the two types of photovoltaic cells in its connected photovoltaic module, enabling the two types of photovoltaic cells in each photovoltaic module to operate in series through the DC / DC converter. In other words, the outputs of the two types of photovoltaic cells in each photovoltaic module are adapted. Furthermore, since the method of adapting the outputs of the two types of photovoltaic cells in each photovoltaic module through the DC / DC converter does not require special treatment of the photovoltaic cell materials or manufacturing processes, it can accommodate most dual-junction photovoltaic modules on the market and save related costs. Moreover, it does not change the original output characteristics of the two types of photovoltaic cells in each photovoltaic module. Therefore, the two types of photovoltaic cells in each photovoltaic module can output according to their respective output characteristics when their photoelectric conversion efficiency is at its highest. Thus, each dual-junction photovoltaic module can achieve the highest photoelectric conversion efficiency, thereby increasing the power generation of the power generation system.

[0109] See Figure 15 , Figure 15 This is another structural schematic diagram of the power generation system provided in this application. For example... Figure 15 As shown, with Figure 8 Compared to the power generation system shown, Figure 15 The photovoltaic modules shown are Figure 8 The integrated photovoltaic modules shown are different: Figure 15 The photovoltaic modules shown do not include a DC / DC converter. Specifically, Figure 15The power generation system shown includes photovoltaic modules 11, ..., photovoltaic modules 1n, DC / DC converters 21, ..., and DC / DC converters 2n, where n is a positive integer. The photovoltaic module 11 includes a first photovoltaic cell PV111 and a second photovoltaic cell PV112 stacked together with different materials. The first output terminal of the first photovoltaic cell PV111 and the first output terminal of the second photovoltaic cell PV112 are both connected to the first output terminal o111 of the photovoltaic module 11. The second output terminal of the first photovoltaic cell PV111 is connected to the second output terminal o112 of the photovoltaic module 11, and the second output terminal of the second photovoltaic cell PV112 is connected to the third output terminal o113 of the photovoltaic module 11. The first input terminal i211 of the DC / DC converter 21 is connected to the first output terminal o113 of the photovoltaic module 11. The first output terminal i111 of the first photovoltaic cell PV111 is connected to the first output terminal o211 of the DC / DC converter 21. The second input terminal i212 of the DC / DC converter 21 is connected to the second output terminal o112 of the photovoltaic module 11. The third input terminal i213 of the DC / DC converter 21 is connected to the third output terminal o113 of the photovoltaic module 11 and the second output terminal o212 of the DC / DC converter 21. The polarity of the first output terminal of the first photovoltaic cell PV111 is the same as the polarity of the first output terminal of the second photovoltaic cell PV112, and opposite to the polarity of the second output terminal o212 of the DC / DC converter 21. ... Photovoltaic module 1n includes a first photovoltaic cell PV1n1 and a second photovoltaic cell PV1n2 stacked together with different materials. The first output terminal of the first photovoltaic cell PV1n1 and the first output terminal of the second photovoltaic cell PV1n2 are both connected to the first output terminal o1n1 of photovoltaic module 1n. The second output terminal of the first photovoltaic cell PV1n1 is connected to the second output terminal o1n2 of photovoltaic module 1n. The second output terminal of the second photovoltaic cell PV1n2 is connected to the third output terminal o1n3 of photovoltaic module 1n. The first input terminal i2n1 of DC / DC converter 2n is connected to the first output terminal i2n1 of photovoltaic module 1n. The first output terminal o111 of the DC / DC converter 2n is connected to the first output terminal o2n1 of the DC / DC converter 2n. The second input terminal i2n2 of the DC / DC converter 2n is connected to the second output terminal o1n2 of the photovoltaic module 1n. The third input terminal i2n3 of the DC / DC converter 2n is connected to the third output terminal o1n3 of the photovoltaic module 1n and the second output terminal o2n2 of the DC / DC converter 2n. The polarity of the first output terminal of the first photovoltaic cell PV1n1 is the same as that of the first output terminal of the second photovoltaic cell PV1n2, and opposite to that of the second output terminal o2n2 of the DC / DC converter 2n. Optionally, the power generation system includes an inverter 3. The output terminals of the DC / DC converter 21, ..., and the output terminals of the DC / DC converter 2n are connected in series to the input terminal of the inverter 3. The output terminal of the inverter 3 is connected to the power grid or a load.

[0110] The n photovoltaic modules provided in this application are dual-junction photovoltaic modules. Furthermore, each DC / DC converter has only two output terminals: a positive output terminal and a negative output terminal. This allows the dual-junction photovoltaic modules configured with DC / DC converters to be connected in series or parallel, just like traditional single-junction photovoltaic modules. Compared to dual-junction photovoltaic modules with four output terminals, this effectively saves on wiring costs between the photovoltaic modules and other equipment.

[0111] Because the materials of the first and second photovoltaic cells in each photovoltaic module are different, their output voltages differ, preventing them from being directly connected in parallel. Therefore, each DC / DC converter converts the output voltage of the first photovoltaic cell in its connected photovoltaic module to the output voltage of the second photovoltaic cell. This ensures that the output voltage of the first photovoltaic cell after conversion is the same as that of the second photovoltaic cell, allowing the two types of photovoltaic cells in each module to operate in parallel via the DC / DC converter.

[0112] Furthermore, since the first output terminals of the two types of photovoltaic cells in each photovoltaic module have both positive and negative polarities, and since the circuit structure and operating principle of each DC / DC converter in the power generation system are the same, for ease of description, the following will combine... Figures 16 to 19 Taking DC / DC converter 21 as an example, for Figure 15 The power generation system shown is described in detail.

[0113] In one embodiment, the polarity of the first output terminal of the first photovoltaic cell and the first output terminal of the second photovoltaic cell in each photovoltaic module are both positive, and the polarity of the second output terminal of each DC / DC converter is negative.

[0114] like Figure 16 As shown, for photovoltaic module 11: when the first photovoltaic cell PV111 and the second photovoltaic cell PV112 are connected with a common positive electrode, the polarity of the output terminals of the first photovoltaic cell PV111, the second photovoltaic cell PV112, photovoltaic module 11, and DC / DC converter 21, as well as the polarity of the input terminal of DC / DC converter 21, can be found in [reference needed]. Figure 9 The descriptions of the corresponding parts in the illustrated embodiments will not be repeated here.

[0115] The DC / DC converter 21 includes a DC / DC conversion circuit and a controller 211. For example, the DC / DC conversion circuit is a negative BUCK circuit 212. For the specific circuit structure of the negative BUCK circuit 212, please refer to [link to relevant documentation]. Figure 9The descriptions of the corresponding parts in the illustrated embodiments will not be repeated here.

[0116] After the DC / DC converter 21 starts working, the controller 211 can control the switching action of the first switch Q1 and the second switch Q2 in the negative BUCK circuit 212 to reduce the output voltage of the first photovoltaic cell PV111 to obtain the same voltage value as the output voltage of the second photovoltaic cell PV112, thereby enabling the first photovoltaic cell PV111 and the second photovoltaic cell PV112 to be connected in parallel through the DC / DC converter 21.

[0117] Optionally, the DC / DC conversion circuit in DC / DC converter 21 can also be a negative boost circuit; please refer to [link to relevant documentation] for details. Figure 17 For the specific circuit structure of the negative BOOST circuit 212, please refer to [link / reference]. Figure 10 The descriptions of the corresponding parts in the illustrated embodiments will not be repeated here.

[0118] After the DC / DC converter 21 starts working, the controller 211 can control the switching action of the first switch Q1 and the second switch Q2 in the negative BOOST circuit 212 to boost the output voltage of the first photovoltaic cell PV111 to obtain the same voltage value as the output voltage of the second photovoltaic cell PV112, thereby enabling the first photovoltaic cell PV111 and the second photovoltaic cell PV112 to be connected in parallel through the DC / DC converter 21.

[0119] Understandably, because the output voltages of the first and second photovoltaic cells in each photovoltaic module differ, they cannot be directly connected in parallel. Therefore, when both types of photovoltaic cells in each module are connected with a common positive terminal, a connection is made by linking the positive input terminal of the DC / DC converter to the positive output terminals of both photovoltaic cells and the DC / DC converter, and connecting the negative output terminal of the second photovoltaic cell to the negative output terminal of the DC / DC converter. This allows the first and second photovoltaic cells to be connected in parallel via the DC / DC converter. Based on this, each DC / DC converter converts the output voltage of the first photovoltaic cell in its connected photovoltaic module to the output voltage of the second photovoltaic cell, ensuring that the output voltage of the first photovoltaic cell after conversion is the same as that of the second photovoltaic cell. This allows the two types of photovoltaic cells in each module to operate in parallel via the DC / DC converter; in other words, it enables the outputs of the two types of photovoltaic cells in each module to be compatible. Furthermore, since the output of the two photovoltaic cells in each photovoltaic module is adapted through a DC / DC converter, there is no special requirement for the photovoltaic cell materials or manufacturing process. Therefore, it can be compatible with most dual-junction photovoltaic modules on the market and save related costs. It also does not change the original output characteristics of the two photovoltaic cells in each photovoltaic module. As a result, the two photovoltaic cells in each photovoltaic module can output according to their respective output characteristics when their photoelectric conversion efficiency is at its highest. Therefore, each dual-junction photovoltaic module can achieve the highest photoelectric conversion efficiency, thereby increasing the power generation of the power generation system.

[0120] In another embodiment, the polarity of the first output terminal of the first photovoltaic cell and the first output terminal of the second photovoltaic cell in each photovoltaic module are both negative, and the polarity of the second output terminal of each DC / DC converter is positive.

[0121] like Figure 18 As shown, for photovoltaic module 11: when the first photovoltaic cell PV111 and the second photovoltaic cell PV112 are connected with a common negative terminal, the polarity of the output terminals of the first photovoltaic cell PV111, the second photovoltaic cell PV112, photovoltaic module 11, and DC / DC converter 21, as well as the polarity of the input terminal of DC / DC converter 21, can be found in [reference needed]. Figure 11 The descriptions of the corresponding parts in the illustrated embodiments will not be repeated here.

[0122] Furthermore, the DC / DC converter 21 includes a DC / DC conversion circuit and a controller 211. Exemplarily, the DC / DC conversion circuit is a BUCK circuit 212. For the specific circuit structure of the BUCK circuit 212, please refer to [link to relevant documentation]. Figure 11The descriptions of the corresponding parts in the illustrated embodiments will not be repeated here.

[0123] After the DC / DC converter 21 starts working, the controller 211 can control the switching action of the first switch Q1 and the second switch Q2 in the negative BUCK circuit 212 to reduce the output voltage of the first photovoltaic cell PV111 to obtain the same voltage value as the output voltage of the second photovoltaic cell PV112, thereby enabling the first photovoltaic cell PV111 and the second photovoltaic cell PV112 to be connected in parallel through the DC / DC converter 21.

[0124] Optionally, the DC / DC conversion circuit in DC / DC converter 21 can also be a BOOST circuit; please refer to [link to details]. Figure 19 For the specific circuit structure of the BOOST circuit 212, please refer to [link / reference]. Figure 12 The descriptions of the corresponding parts in the illustrated embodiments will not be repeated here.

[0125] After the DC / DC converter 21 starts working, the controller 211 can control the switching action of the first switch Q1 and the second switch Q2 in the BOOST circuit 212 to boost the output voltage of the first photovoltaic cell PV111 to obtain the same voltage value as the output voltage of the second photovoltaic cell PV112, thereby enabling the first photovoltaic cell PV111 and the second photovoltaic cell PV112 to be connected in parallel through the DC / DC converter 21.

[0126] Understandably, because the output voltages of the first and second photovoltaic cells in each photovoltaic module differ, they cannot be directly connected in parallel. Therefore, when both types of photovoltaic cells in each module are connected with a common negative terminal, a connection is made by linking the negative input terminal of the DC / DC converter to the negative output terminals of both photovoltaic cells and the negative output terminal of the DC / DC converter, and connecting the positive output terminal of the second photovoltaic cell to the positive output terminal of the DC / DC converter. This allows the first and second photovoltaic cells to be connected in parallel via the DC / DC converter. Based on this, each DC / DC converter converts the output voltage of the first photovoltaic cell in its connected photovoltaic module to the output voltage of the second photovoltaic cell, ensuring that the output voltage of the first photovoltaic cell in each module after conversion is the same as that of the second photovoltaic cell. This allows the two types of photovoltaic cells in each module to operate in parallel via the DC / DC converter; in other words, it enables the outputs of the two types of photovoltaic cells in each module to be compatible. Furthermore, since the output of the two photovoltaic cells in each photovoltaic module is adapted through a DC / DC converter, there is no special requirement for the photovoltaic cell materials or manufacturing process. Therefore, it can be compatible with most dual-junction photovoltaic modules on the market and save related costs. It also does not change the original output characteristics of the two photovoltaic cells in each photovoltaic module. As a result, the two photovoltaic cells in each photovoltaic module can output according to their respective output characteristics when their photoelectric conversion efficiency is at its highest. Therefore, each dual-junction photovoltaic module can achieve the highest photoelectric conversion efficiency, thereby increasing the power generation of the power generation system.

[0127] In this application, since the output voltage of the first photovoltaic cell in each photovoltaic module is different from that of the second photovoltaic cell, the first and second photovoltaic cells in each photovoltaic module cannot be directly connected in parallel. Therefore, when the first photovoltaic cell in each photovoltaic module is connected in parallel with the second photovoltaic cell through a DC / DC converter, each DC / DC converter can convert the output voltage of the first photovoltaic cell in its connected photovoltaic module into the output voltage of the second photovoltaic cell. This makes the output voltage of the first photovoltaic cell in each photovoltaic module after being converted by the DC / DC converter the same as the output voltage of the second photovoltaic cell. In other words, the two types of photovoltaic cells in each photovoltaic module can work in parallel through the DC / DC converter, making the outputs of the two types of photovoltaic cells in each photovoltaic module compatible. Furthermore, because the DC / DC converter adapts the outputs of the two photovoltaic cells in each photovoltaic module, it does not require special treatment of the photovoltaic cell materials or manufacturing processes. Therefore, it can accommodate most dual-junction photovoltaic modules on the market while saving related costs, and it does not change the original output characteristics of the two photovoltaic cells in each module. Thus, the two photovoltaic cells in each module can output according to their respective output characteristics at their highest photoelectric conversion efficiency. Therefore, each dual-junction photovoltaic module can achieve the highest photoelectric conversion efficiency, thereby increasing the power generation of the power generation system. In addition, the parallel connection of the two photovoltaic cells in each photovoltaic module through the DC / DC converter can be either a common positive terminal connection or a common negative terminal connection, allowing for diverse structures of photovoltaic modules and DC / DC converters, thereby increasing the structural diversity of the power generation system.

[0128] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An integrated photovoltaic module, characterized in that, The integrated photovoltaic module includes a DC / DC converter, a photovoltaic junction box, and a first photovoltaic cell and a second photovoltaic cell stacked together with different materials. The DC / DC converter is located inside the photovoltaic junction box, wherein: The first photovoltaic cell and the second photovoltaic cell are connected in series between the first and second input terminals of the DC / DC converter. The connection between the first and second photovoltaic cells is connected to the third input terminal of the DC / DC converter. The output terminal of the DC / DC converter is connected to the output terminal of the integrated photovoltaic module. The first photovoltaic cell and the second photovoltaic cell are used to convert the absorbed solar energy into electrical energy; The DC / DC converter is used to compensate for the difference between the output current of the first photovoltaic cell and the output current of the second photovoltaic cell.

2. The integrated photovoltaic module according to claim 1, characterized in that, The number of output terminals of the integrated photovoltaic module is 2.

3. The integrated photovoltaic module according to claim 1 or 2, characterized in that, The DC / DC converter includes a first switching transistor, a second switching transistor, an inductor, and a controller, wherein: The first switch and the second switch are connected in series between the first input terminal and the second input terminal of the DC / DC converter, and the inductor is connected between the third input terminal of the DC / DC converter and the connection point of the first switch and the second switch. The controller is used to control the first switch and the second switch to conduct in a complementary manner to compensate for the difference between the output current of the first photovoltaic cell and the output current of the second photovoltaic cell.

4. The integrated photovoltaic module according to claim 3, characterized in that, The output current of the first photovoltaic cell is greater than the output current of the second photovoltaic cell; The controller is used to control the first switch and the second switch to be complementary in conduction, and the duty cycle of the first switch is greater than the duty cycle of the second switch.

5. An integrated photovoltaic module, characterized in that, The integrated photovoltaic module includes a DC / DC converter, a photovoltaic junction box, and a first photovoltaic cell and a second photovoltaic cell stacked together with different materials. The DC / DC converter is located inside the photovoltaic junction box, wherein: The first output terminal of the first photovoltaic cell and the first output terminal of the second photovoltaic cell are both connected to the first input terminal of the DC / DC converter. The second output terminal of the first photovoltaic cell is connected to the second input terminal of the DC / DC converter, and the second output terminal of the second photovoltaic cell is connected to the third input terminal of the DC / DC converter. The first photovoltaic cell and the second photovoltaic cell are used to convert the absorbed solar energy into electrical energy. The first output terminal of the DC / DC converter is connected to the first input terminal of the DC / DC converter and the first output terminal of the integrated photovoltaic module. The second output terminal of the DC / DC converter is connected to the third input terminal of the DC / DC converter and the second output terminal of the integrated photovoltaic module. The DC / DC converter is used to convert the output voltage of the first photovoltaic cell into the output voltage of the second photovoltaic cell. The polarity of the first output terminal of the first photovoltaic cell is the same as that of the first output terminal of the second photovoltaic cell, and opposite to that of the second output terminal of the DC / DC converter.

6. The integrated photovoltaic module according to claim 5, characterized in that, The number of output terminals of the integrated photovoltaic module is 2.

7. The integrated photovoltaic module according to claim 5 or 6, characterized in that, When the polarity of the first output terminal of the first photovoltaic cell is negative, the DC / DC converter includes a BUCK circuit or a BOOST circuit.

8. The integrated photovoltaic module according to claim 5 or 6, characterized in that, When the polarity of the first output terminal of the first photovoltaic cell is positive, the DC / DC converter includes an inverted circuit of the BUCK circuit or an inverted circuit of the BOOST circuit.

9. A power generation system, characterized in that, The power generation system includes photovoltaic modules and a DC / DC converter. The photovoltaic modules include a first photovoltaic cell and a second photovoltaic cell stacked together with different materials, wherein: The first photovoltaic cell and the second photovoltaic cell are connected in series between the first output terminal and the second output terminal of the photovoltaic module. The connection between the first photovoltaic cell and the second photovoltaic cell is connected to the third output terminal of the photovoltaic module. The first photovoltaic cell and the second photovoltaic cell are used to convert the absorbed solar energy into electrical energy. The first input terminal of the DC / DC converter is connected to the first output terminal of the photovoltaic module, the second input terminal of the DC / DC converter is connected to the second output terminal of the photovoltaic module, and the third input terminal of the DC / DC converter is connected to the third output terminal of the photovoltaic module. The DC / DC converter is used to compensate for the difference between the output current of the first photovoltaic cell and the output current of the second photovoltaic cell.

10. The power generation system according to claim 9, characterized in that, The DC / DC converter has two output terminals.

11. The power generation system according to claim 9 or 10, characterized in that, The power generation system includes multiple photovoltaic modules, multiple DC / DC converters, and inverters. The multiple photovoltaic modules are connected one-to-one with the multiple DC / DC converters. The output terminals of the multiple DC / DC converters are connected in series with the input terminals of the inverters. The output terminals of the inverters are used to connect to the power grid or a load.

12. A power generation system, characterized in that, The power generation system includes photovoltaic modules and a DC / DC converter. The photovoltaic modules include a first photovoltaic cell and a second photovoltaic cell stacked together with different materials, wherein: The first output terminal of the first photovoltaic cell and the first output terminal of the second photovoltaic cell are both connected to the first output terminal of the photovoltaic module. The second output terminal of the first photovoltaic cell is connected to the second output terminal of the photovoltaic module. The second output terminal of the second photovoltaic cell is connected to the third output terminal of the photovoltaic module. The first photovoltaic cell and the second photovoltaic cell are used to convert the absorbed solar energy into electrical energy. The first input terminal of the DC / DC converter is connected to the first output terminal of the photovoltaic module and the first output terminal of the DC / DC converter. The second input terminal of the DC / DC converter is connected to the second output terminal of the photovoltaic module. The third input terminal of the DC / DC converter is connected to the third output terminal of the photovoltaic module and the second output terminal of the DC / DC converter. The DC / DC converter is used to convert the output voltage of the first photovoltaic cell into the output voltage of the second photovoltaic cell. The polarity of the first output terminal of the first photovoltaic cell is the same as that of the first output terminal of the second photovoltaic cell, and opposite to that of the second output terminal of the DC / DC converter.

13. The power generation system according to claim 12, characterized in that, The DC / DC converter has two output terminals.

14. The power generation system according to claim 12 or 13, characterized in that, The power generation system includes multiple photovoltaic modules, multiple DC / DC converters, and an inverter. The multiple photovoltaic modules are connected one-to-one with the multiple DC / DC converters. The output terminals of the multiple DC / DC converters are connected in series with the input terminals of the inverters. The output terminals of the inverters are used to connect to the power grid or a load.

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