A photovoltaic power generation system

Abstract

The utility model discloses a photovoltaic power generation system, include: at least two rows photovoltaic group string and at least two maximum power point tracking MPPT unit, photovoltaic group string extends along the first direction and is arranged along the second direction interval, and photovoltaic group string is connected with MPPT unit corresponding, and the MPPT unit of different rows photovoltaic group string connection is different, the first direction and the second direction cross, MPPT unit is used for real -time detection voltage to track the highest voltage current value, the utility model discloses can improve photovoltaic power generation system's power generation power.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic power generation technology, and in particular to a photovoltaic power generation system. Background Technology

[0002] A photovoltaic (PV) power generation system is a device that converts solar energy into electrical energy, which is then connected to the power system for user use.

[0003] A photovoltaic (PV) power generation system consists of multiple rows of photovoltaic (PV) strings, typically installed on a rooftop, and then converted using an inverter circuit. Existing PV power generation systems suffer from low power output. Utility Model Content

[0004] This invention provides a photovoltaic power generation system that can improve the power generation capacity of the photovoltaic power generation system.

[0005] This utility model provides a photovoltaic power generation system, including: at least two rows of photovoltaic strings and at least two maximum power point tracking (MPPT) units; each row of photovoltaic strings includes at least one photovoltaic string; the photovoltaic strings extend along a first direction and are arranged at intervals along a second direction, the photovoltaic strings are connected to MPPT units correspondingly, and the MPPT units connected to different rows of photovoltaic strings are different; the first direction and the second direction intersect; the MPPT units are used to detect voltage in real time and track the highest voltage and current values.

[0006] Optionally, the photovoltaic string includes N photovoltaic modules; N is an integer greater than or equal to 2; the positive terminal of the first photovoltaic module is connected to the positive input terminal of the corresponding MPPT unit, the negative terminal of the i-th photovoltaic module is connected to the positive terminal of the (i+1)-th photovoltaic module, and the negative terminal of the last photovoltaic module is connected to the negative input terminal of the corresponding MPPT unit, where i is an integer greater than or equal to 1 and less than N.

[0007] Optionally, the photovoltaic power generation system further includes a first electromagnetic interference (EMI) filter and at least one DC switch, with each photovoltaic string connected to a corresponding DC switch; each DC switch is connected to a corresponding MPPT unit through the first EMI filter.

[0008] Optionally, the photovoltaic power generation system also includes a DC surge protector, which connects each DC switch to the terminal of the first EMI filter.

[0009] Optionally, the photovoltaic power generation system also includes a control unit, which is connected to the photovoltaic string and the DC switch, for detecting the electrical parameters of the photovoltaic string and controlling the switching state of the DC switch according to the electrical parameters.

[0010] Optionally, the photovoltaic power generation system also includes an inverter unit. The positive output terminal of the MPPT unit is connected in parallel and then electrically connected to the positive input terminal of the inverter unit. The negative output terminal of the MPPT unit is connected in parallel and then electrically connected to the negative input terminal of the inverter unit. The inverter unit is used to convert the DC power delivered by each MPPT unit into AC power.

[0011] Optionally, the photovoltaic power generation system also includes an output filter and a second EMI filter, with the output of the inverter unit connected to the second EMI filter via the output filter.

[0012] Optionally, the photovoltaic power generation system also includes an AC surge protector, with the output of the second EMI filter connected to the AC surge protector.

[0013] Optionally, an output relay is connected between the output filter and the second EMI filter.

[0014] Optionally, the photovoltaic power generation system also includes an adjustment module connected to the MPPT unit, which is used to adjust the current of the MPPT unit.

[0015] The photovoltaic power generation system provided in this embodiment avoids mutual interference caused by differences in power generation performance due to varying effects of shading on different rows of photovoltaic strings by connecting them to different MPPT units. When the power generation performance of a certain row of photovoltaic strings decreases due to shading, the MPPT unit connected to it can independently perform maximum power point tracking on that string without affecting other rows of photovoltaic strings that are generating power normally. For example, if the front row of photovoltaic modules is shaded in the morning while the rear row is not, the power generation of the front row of photovoltaic modules will be low. If it is connected to the same MPPT unit as the rear row of photovoltaic modules, it will lower the power generation of the entire photovoltaic string. However, with this design, the MPPT unit connected to the front row of photovoltaic modules will optimize for its current state, and the MPPT unit connected to the rear row of photovoltaic modules can also ensure that its normal power generation is not affected, thereby improving the power generation of the entire photovoltaic power generation system.

[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a photovoltaic power generation system provided in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of another photovoltaic power generation system provided in this embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the structure of another photovoltaic power generation system provided in this embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of another photovoltaic power generation system provided in this embodiment of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0024] According to the photovoltaic design standard "Design Code for Photovoltaic Power Stations GB50797-2012", the spacing between rows and columns of photovoltaic arrays should ensure that there is no shading between the front, back, left, and right sides during the period from 9:00 to 15:00 (local true solar time). Existing matching wiring between photovoltaic strings and inverters is based on this. To reduce wiring costs and construction expenses, a C-type wiring method with two rows of modules is generally adopted. In the C-type wiring method, the positive and negative terminals of the photovoltaic string are on the same side. Compared with the straight-line wiring method, a single photovoltaic string saves at least 22-30 meters of dedicated DC photovoltaic cable, which meets the design standard. However, photovoltaic strings from different rows are mixed and connected to the same MPPT unit. Because of the large number of devices on the roof, shadows appear in the installation area at different times of day. As the sun rises, the shadows on different rows of photovoltaic (PV) strings dissipate at different times, resulting in varying power generation performance and maximum power points (MPPTs) for different rows of PV strings within the same time period. When modules with different power generation characteristics are mixed and connected to the same MPPT unit—for example, modules with slower shadow dissipation have lower power output, while those with faster dissipation have higher power output—the overall power generation of the PV system depends on the weakest performing component (the "weakest link"), reducing the overall power output of the PV system.

[0025] To address the problems in the existing technology, this utility model provides a photovoltaic power generation system. Figure 1 This is a schematic diagram of the structure of a photovoltaic power generation system provided in an embodiment of this utility model. Figure 1 As shown, the photovoltaic power generation system includes at least two rows of photovoltaic strings 110 and at least two maximum power point tracking (MPPT) units 12. The photovoltaic strings 110 extend along a first direction X and are arranged at intervals along a second direction Y. The photovoltaic strings 110 are connected to the MPPT units 12, and different MPPT units 12 are connected to different rows of photovoltaic strings 110. The first direction X and the second direction Y intersect. The MPPT units 12 are used to detect voltage in real time and track the highest voltage and current values. Optionally, the first direction X is perpendicular to the second direction Y.

[0026] Specifically, the photovoltaic string 11 includes at least one photovoltaic string, which is a circuit unit composed of multiple photovoltaic modules connected in series. Its purpose is to increase the output voltage to meet the input requirements of equipment such as inverters. In a photovoltaic power generation system, photovoltaic modules are the basic units for converting solar energy into electrical energy. Connecting multiple modules in series can increase the voltage, facilitating the transmission and subsequent processing of electrical energy. For example, a typical photovoltaic string may consist of 20-30 photovoltaic modules connected in series, the specific number depending on the system design, inverter parameters, and module parameters.

[0027] The Maximum Power Point Tracking (MPPT) unit 12 is used to detect the output voltage and current of the photovoltaic (PV) string in real time and track the maximum power point of the PV string through a specific control algorithm. Since the output power of the PV module varies non-linearly with environmental factors such as light intensity and temperature, there exists a maximum power point. The MPPT unit 12 continuously adjusts the operating point (i.e., the combination of voltage and current) of the PV string to ensure it always operates near the maximum power point, thereby maximizing the power generation efficiency of the PV power generation system. For example, when the light intensity increases, the MPPT unit 12 will promptly adjust the operating voltage of the PV string to maximize the output power.

[0028] The first direction X and the second direction Y are two intersecting directions used to describe the arrangement of photovoltaic strings 11. The first direction X is usually the length direction of the photovoltaic string 11, that is, the direction in which the photovoltaic modules are connected in series; the second direction Y is the spacing direction between the photovoltaic strings 11, used to determine the positional relationship between different rows of photovoltaic strings. For example, the first direction X can be east-west (if the photovoltaic modules are arranged in an east-west direction to better receive sunlight), then the second direction Y is north-south. This layout allows the photovoltaic strings to receive good sunlight at different times, while making reasonable use of space and ensuring that the modules in front and behind do not block each other for a certain period of time.

[0029] Optionally, a row may include multiple photovoltaic strings 11. The MPPT units 12 connected to the photovoltaic strings 11 in the same row can be the same or different, as long as the MPPT units 12 connected to the photovoltaic strings 11 in different rows are different. When the photovoltaic strings 11 in the same row are connected to the same MPPT unit 12, a parallel connection method can be adopted. Using a DC cable of appropriate specification, the positive terminal of multiple photovoltaic strings 11 is connected to the positive input terminal of the MPPT unit 12, and the negative terminal is connected to the negative input terminal. When the photovoltaic strings 11 in the same row are connected to different MPPT units 12, in a similar manner to connecting different MPPT units 12 in different rows, each photovoltaic string 11 is connected to the corresponding MPPT unit 12 through an independent cable to ensure the accuracy and stability of the connection.

[0030] Each MPPT unit 12 can perform precise maximum power point tracking based on the actual power generation characteristics of the connected photovoltaic strings. Different rows of photovoltaic strings 11 have different power generation characteristics due to variations in sunlight conditions and shading. Connecting different MPPT units 12 allows for personalized optimization of each row of modules. For example, at different times of the day, the shading and sunlight intensity of different rows of modules vary, and each MPPT unit 12 can adjust its operating point in real time, ensuring the entire photovoltaic power generation system maintains high power generation efficiency. Compared to the method of connecting adjacent rows of photovoltaic modules to the same MPPT unit 12 (i.e., C-type connection), this method utilizes solar energy resources more effectively and reduces power generation efficiency losses caused by module mismatch and other issues.

[0031] Different MPPT units 12 can independently monitor and control the connected photovoltaic strings, facilitating system fault diagnosis and maintenance. If a row of photovoltaic strings or its connected MPPT units 12 malfunctions, the problem is easier to locate and resolve without affecting other normally functioning components. Furthermore, it allows for more flexible management of different rows of photovoltaic strings during system expansion or adjustments. For example, when adding new photovoltaic strings, they can be connected to appropriate MPPT units 12 based on actual conditions, or the parameters of existing MPPT units 12 can be adjusted to accommodate new components, improving the system's scalability and adaptability.

[0032] The photovoltaic power generation system provided in this embodiment avoids mutual interference caused by differences in power generation performance due to varying effects of shading on different rows of photovoltaic strings by connecting them to different MPPT units. When the power generation performance of a certain row of photovoltaic strings decreases due to shading, the MPPT unit connected to it can independently perform maximum power point tracking on that string without affecting other rows of photovoltaic strings that are generating power normally. For example, if the front row of photovoltaic modules is shaded in the morning while the rear row is not, the power generation of the front row of photovoltaic modules will be low. If it is connected to the same MPPT unit as the rear row of photovoltaic modules, it will lower the power generation of the entire photovoltaic string. However, with this design, the MPPT unit connected to the front row of photovoltaic modules will optimize for its current state, and the MPPT unit connected to the rear row of photovoltaic modules can also ensure that its normal power generation is not affected, thereby improving the power generation of the entire photovoltaic power generation system.

[0033] Figure 2 This is a schematic diagram of another photovoltaic power generation system provided in this embodiment of the utility model. (See attached diagram.) Figure 2 As shown, the photovoltaic string 11 includes N photovoltaic modules 110; N is an integer greater than or equal to 2.

[0034] The positive terminal of the first photovoltaic module 110 is connected to the positive input terminal of the corresponding MPPT unit 12, the negative terminal of the i-th photovoltaic module 110 is connected to the positive terminal of the (i+1)-th photovoltaic module 110, and the negative terminal of the last photovoltaic module 110 is connected to the negative input terminal of the corresponding MPPT unit 12, where i is an integer greater than or equal to 1 and less than N. Figure 2 The case where N=3 is illustrated.

[0035] The positive terminal of the first photovoltaic module 110 is connected to the positive input terminal of the corresponding MPPT unit 12, and the negative terminal of the last photovoltaic module 110 is connected to the negative input terminal of the corresponding MPPT unit 12. This connection method allows the MPPT unit 12 to completely acquire the voltage and current information of the photovoltaic string 11. By monitoring the voltage and current at these two input terminals, the MPPT unit 12 uses its internal control algorithm (such as perturbation observation method, conductance increment method, etc.) to track the maximum power point of the photovoltaic string 11. For example, when the light intensity changes, the output voltage and current of the photovoltaic string 11 will change accordingly. The MPPT unit 12 can adjust the operating point in real time according to these changes, so that the photovoltaic string 11 always operates near the maximum power point, thereby improving the power generation efficiency.

[0036] Figure 3 This is a schematic diagram of another photovoltaic power generation system provided in this embodiment of the utility model. (See attached diagram.) Figure 3 As shown, optionally, the photovoltaic power generation system further includes a first electromagnetic interference (EMI) filter 13 and at least one DC switch 14, with each photovoltaic string 11 connected to a corresponding DC switch 14. Each DC switch 14 is connected to a corresponding MPPT unit 12 via the first EMI filter 13.

[0037] The first EMI filter 13 is mainly used to filter out electromagnetic interference signals generated by the photovoltaic string 11 during power generation. It also prevents external electromagnetic interference from entering the system, protecting the normal operation of electrical equipment within the system. In a photovoltaic power generation system, the operation of the photovoltaic module 110 and the transmission of current generate electromagnetic signals of various frequencies. These interference signals may affect the performance of other electronic devices in the system (such as the MPPT unit 12), leading to malfunctions and reduced power generation efficiency. The first EMI filter 13 can include components such as inductors and capacitors. Through the impedance of the inductor to high-frequency current and the bypassing effect of the capacitor on high-frequency signals, unwanted electromagnetic interference signals are filtered out. For example, for high-frequency interference signals, the impedance of the inductor increases, making it difficult for the signal to pass through, while the capacitor provides a low-impedance path for the high-frequency signal, bypassing it to ground, thereby achieving the filtering effect.

[0038] DC switch 14 controls the on / off state of the circuit between photovoltaic string 11 and MPPT unit 12. During normal operation of the photovoltaic power generation system, DC switch 14 is closed, allowing photovoltaic string 11 to transmit the generated DC power to MPPT unit 12 for maximum power point tracking and subsequent processing. During system maintenance, troubleshooting, or when individual operation of a photovoltaic string 11 is required, DC switch 14 can be opened to isolate that photovoltaic string 11 from the photovoltaic power generation system, facilitating related work while ensuring the safety of operators.

[0039] Working principle: The DC switch 14 changes its on and off states according to the control signal. Common types of DC switches 14 include relay switches and transistor switches. For example, a relay switch uses electromagnetic force to close or open contacts to switch the circuit on or off; a transistor switch uses the on and off characteristics of semiconductor devices to control the flow of current.

[0040] Optionally, continue to refer to Figure 3 The photovoltaic power generation system also includes a DC surge protector 15, which is connected to the terminal of each DC switch 14 and the first EMI filter 13.

[0041] DC surge protector 15 protects the system from DC surge current. In photovoltaic power generation systems, instantaneous high voltage and high current surges may occur due to lightning, grid failures, etc. Without protection, these surge currents may damage equipment such as photovoltaic modules 110, MPPT units 12, and DC switches 14. DC surge protector 15 can quickly guide surge currents to the ground when they occur, thereby protecting the safety of the system equipment.

[0042] The DC surge protector 15 may include components such as varistors and gas discharge tubes. When the surge voltage exceeds a certain value, the resistance of these components drops rapidly, bypassing the surge current to ground. After the surge disappears, the components return to a high-resistance state, without affecting the normal operation of the system. For example, a varistor exhibits a high-resistance state under normal voltage, having little impact on the system current. However, when the surge voltage exceeds its threshold, the resistance drops sharply, forming a low-resistance path and discharging the surge current.

[0043] Optionally, continue to refer to Figure 3 The photovoltaic power generation system also includes a control unit, which is connected to the photovoltaic string 11 and the DC switch 14. The control unit is used to detect the electrical parameters of the photovoltaic string 11 and control the switching state of the DC switch 14 according to the electrical parameters.

[0044] The control unit is responsible for detecting the electrical parameters of the photovoltaic string 11, such as voltage, current, and power, and controlling the switching state of the DC switch 14 based on these parameters. By monitoring the operating status of the photovoltaic string 11 in real time, the control unit can achieve intelligent management of the system. For example, when an abnormal drop in the power generation of a photovoltaic string 11 is detected (possibly due to component damage, shading, etc.), the control unit can control the corresponding DC switch 14 to disconnect, isolating the string, and simultaneously issue an alarm to remind maintenance personnel to check and handle the issue.

[0045] The control unit may include components such as sensors and a microprocessor. Sensors are used to collect electrical parameters of the photovoltaic string 11. The microprocessor analyzes and processes the collected data and generates control signals based on preset logic and algorithms to control the operation of the DC switch 14. For example, the microprocessor determines whether the current of the photovoltaic string 11 is abnormal based on a set threshold; if it is below the normal range, it issues a command to disconnect the DC switch 14.

[0046] Optionally, continue to refer to Figure 3 The photovoltaic power generation system also includes an inverter unit 17. The positive output terminal of the MPPT unit 12 is connected in parallel and then electrically connected to the positive input terminal of the inverter unit 17. The negative output terminal of the MPPT unit 12 is connected in parallel and then electrically connected to the negative input terminal of the inverter unit 17. The inverter unit 17 is used to convert the DC power delivered by each MPPT unit 12 into AC power.

[0047] Inverter unit 17 converts the direct current output from MPPT unit 12 into alternating current so that the electrical energy can be fed into the power grid or used by AC loads. In a photovoltaic power generation system, photovoltaic module 110 generates direct current, but most electrical equipment and the power grid use alternating current, so inverter unit 17 is needed to convert the form of electrical energy.

[0048] Optionally, the inverter unit 17 utilizes the switching characteristics of power semiconductor devices (such as IGBTs, MOSFETs, etc.) to convert DC power into AC power by controlling the conduction and cutoff of these devices. For example, through a certain control circuit, the power semiconductor devices are turned on and off at a specific frequency and phase, chopping the DC voltage into a series of pulse voltages. Then, the pulse voltages are smoothed into an approximately sinusoidal AC power by a filter circuit. Its output voltage and frequency can be adjusted according to the grid requirements or load demands.

[0049] Optionally, continue to refer to Figure 3 The photovoltaic power generation system also includes an output filter 18 and a second EMI filter 19. The output terminal of the inverter unit 17 is connected to the second EMI filter 19 through the output filter 18.

[0050] The output filter 18 filters the AC output from the inverter unit 17, removing harmonic components and making the output AC more closely resemble an ideal sine wave. Harmonics can adversely affect the power grid and electrical equipment, such as increasing grid losses, causing equipment overheating, and interfering with communications. The output filter 18 can effectively reduce these problems.

[0051] The output filter 18 can be an LC filter composed of inductors, capacitors, or other types of filters. Inductors exhibit different impedances to currents of different frequencies, significantly impeding harmonic currents. Capacitors, on the other hand, bypass harmonic currents. Through the combined effect of inductors and capacitors, harmonics are filtered out. For example, for low-frequency harmonics, the inductor's higher impedance prevents them from passing through, while the capacitor provides a low-impedance path for high-frequency harmonics, allowing them to bypass to ground, thus obtaining a relatively pure sinusoidal alternating current.

[0052] The second EMI filter 19 further filters out electromagnetic interference signals generated by the inverter unit 17 during the conversion of DC to AC, preventing these interference signals from entering the power grid or affecting surrounding electronic equipment. During the inverter process, the rapid switching of power semiconductor devices generates electromagnetic interference, which the second EMI filter 19 can effectively suppress, ensuring the electromagnetic compatibility of the system.

[0053] Similar to the first EMI filter 13, the second EMI filter 19 can also use components such as inductors and capacitors to filter electromagnetic interference signals. By properly designing the values ​​of the inductors and capacitors, they can achieve good filtering effects on interference signals within a specific frequency range, attenuating the interference signals to a level that meets relevant standards and avoiding adverse effects on the power grid and other equipment.

[0054] Optionally, continue to refer to Figure 3 It also includes an AC surge protector 20, and the output of the second EMI filter 19 is connected to the AC surge protector 20.

[0055] AC surge protector 20 protects the photovoltaic power generation system from the impact of AC surge current. When surge voltages caused by lightning, switching operations, etc. occur in the power grid, AC surge protector 20 can quickly guide the surge current to the ground, protecting the inverter unit 17, output filter 18, and electrical equipment from damage.

[0056] The AC surge protector 20 may include components such as a metal oxide varistor (MOV). When the AC surge voltage exceeds the MOV's threshold, its resistance drops rapidly, bypassing the surge current to ground. After the surge disappears, the MOV returns to a high-resistance state, without affecting the normal operation of the system. Unlike the DC surge protector 15, the AC surge protector 20 needs to adapt to the periodic changes in AC voltage, and its design and parameter selection must consider factors such as the peak value and frequency of the AC voltage.

[0057] Optionally, continue to refer to Figure 3 An output relay 16 is connected between the output filter 18 and the second EMI filter 19.

[0058] Output relay 16 controls whether the AC power output by inverter unit 17 is connected to the power grid or load. When the photovoltaic power generation system is operating normally and meets certain conditions (such as stable output voltage and frequency, phase matching, etc.), output relay 16 closes to transmit electrical energy; when the photovoltaic power generation system starts up, stops, or malfunctions, output relay 16 can open to isolate and protect the system.

[0059] The output relay 16 controls the closing and opening of the relay contacts according to a control signal (such as a signal from a control unit or other control device). When the control signal energizes the relay coil, it generates an electromagnetic force that closes the contacts, thus completing the circuit. When the control signal disappears, the coil is de-energized, and the contacts open under the action of a spring or other mechanical device, cutting off the circuit.

[0060] Figure 4 This is a schematic diagram of another photovoltaic power generation system provided in this embodiment of the utility model. (See attached diagram.) Figure 4 As shown, optionally, the photovoltaic power generation system further includes an adjustment module 21, which is connected to the MPPT unit 12 and is used to adjust the MPPT unit 12.

[0061] When the current flowing through MPPT unit 12 is greater than or equal to the limit current of MPPT unit 12, the adjustment module 21 adjusts the current in MPPT unit 12 so that the current flowing through MPPT unit 12 is less than the limit current. When the current flowing through MPPT unit 12 is less than the limit current of MPPT unit 12, the adjustment module does not need to adjust the current in MPPT unit 12. For example, the adjustment module 21 may include an absorption unit and a compensation unit. The photovoltaic power generation system may include multiple photovoltaic strings, multiple MPPT units, multiple inverter units, and grid loads. By adjusting the current in the photovoltaic power generation system through the adjustment module 21 so that the current in MPPT unit 12 is less than the limit current corresponding to MPPT unit 12, the situation where the complete current-voltage curve of the photovoltaic power generation system cannot be scanned when the current in the photovoltaic power generation system is greater than the limit current of MPPT unit 12 is solved.

[0062] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A photovoltaic power generation system, characterized in that, include: At least two rows of photovoltaic strings and at least two maximum power point tracking (MPPT) units; The photovoltaic strings extend along a first direction and are arranged at intervals along a second direction. The photovoltaic strings are connected to the MPPT units respectively, and the MPPT units connected to different rows of photovoltaic strings are different; the first direction and the second direction intersect. The MPPT unit is used to detect voltage in real time and track the highest voltage and current values.

2. The photovoltaic power generation system according to claim 1, characterized in that, The photovoltaic string comprises N photovoltaic modules; N is an integer greater than or equal to 2; The positive terminal of the first photovoltaic module is connected to the positive input terminal of the corresponding MPPT unit, the negative terminal of the i-th photovoltaic module is connected to the positive terminal of the (i+1)-th photovoltaic module, and the negative terminal of the last photovoltaic module is connected to the negative input terminal of the corresponding MPPT unit, where i is an integer greater than or equal to 1 and less than N.

3. The photovoltaic power generation system according to claim 2, characterized in that, It also includes a first EMI filter and at least one DC switch, with each of the photovoltaic strings connected to the corresponding DC switch; Each of the DC switches is connected to the corresponding MPPT unit via the first EMI filter.

4. The photovoltaic power generation system according to claim 3, characterized in that, It also includes a DC surge protector, which is connected to the junction of each of the DC switches and the first EMI filter.

5. The photovoltaic power generation system according to claim 4, characterized in that, It also includes a control unit, which is connected to the photovoltaic string and the DC switch, for detecting the electrical parameters of the photovoltaic string and controlling the switching state of the DC switch according to the electrical parameters.

6. The photovoltaic power generation system according to claim 1, characterized in that, It also includes an inverter unit, wherein the positive output terminal of the MPPT unit is connected in parallel and then electrically connected to the positive input terminal of the inverter unit. The negative output terminal of the MPPT unit is connected in parallel and then electrically connected to the negative input terminal of the inverter unit. The inverter unit is used to convert the DC power supplied by each MPPT unit into AC power.

7. The photovoltaic power generation system according to claim 6, characterized in that, It also includes an output filter and a second EMI filter, with the output terminal of the inverter unit connected to the second EMI filter via the output filter.

8. The photovoltaic power generation system according to claim 7, characterized in that, It also includes an AC surge protector, the output of which is connected to the AC surge protector.

9. The photovoltaic power generation system according to claim 7, characterized in that, An output relay is connected between the output filter and the second EMI filter.

10. The photovoltaic power generation system according to claim 1, characterized in that, It also includes an adjustment module, which is connected to the MPPT unit and is used to adjust the current of the MPPT unit.

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