A control method and control device for a photovoltaic inverter system

Abstract

This application relates to a control method and control device for a photovoltaic inverter system, belonging to the technical field of power control systems. The method includes: determining whether a voltage over-limit has occurred; if so, adjusting the voltage sequentially through the photovoltaic inverters in the first group of reactive power regulation; after each photovoltaic inverter in the first group of reactive power regulation has been regulated, re-determining whether a voltage over-limit exists; if so, proceeding to the next photovoltaic inverter; if the voltage over-limit still exists after the photovoltaic inverters in the first group of reactive power regulation have been regulated, adjusting the voltage sequentially through the charging power of the energy storage devices in the first group of active power regulation; after each energy storage device in the first group of active power regulation has been regulated, re-determining whether a voltage over-limit exists; if so, proceeding to the next energy storage device; if the voltage over-limit regulation is completed according to the energy storage devices in the first group of active power regulation, the regulation action ends.

Description

Technical Field

[0001] This application relates to the technical field of power control systems, and in particular to a control method and control device for a photovoltaic inverter system. Background Technology

[0002] With the continuous advancement and widespread application of distributed photovoltaic (PV) power generation technology, low-voltage distribution networks face new challenges in voltage control. Especially with large-scale PV systems integrated into the grid, voltage exceeding limits becomes particularly significant, affecting not only the stability and reliability of the grid but also posing a potential threat to users' electricity safety. Traditional voltage control methods, such as the application of reactive power compensation equipment and the reduction of PV power output, can alleviate voltage problems to some extent, but these methods often suffer from limitations such as low efficiency, high cost, or slow response speed. How to better solve this technical problem is a challenge that those skilled in the art need to overcome. Summary of the Invention

[0003] To at least partially solve the above-mentioned technical problems, this application provides a control method and control device for a photovoltaic inverter system.

[0004] Firstly, the control method for a photovoltaic inverter system provided in this application adopts the following technical solution.

[0005] A control method for a photovoltaic inverter system, comprising: Determine if a voltage limit violation has occurred; if so, adjust the voltage sequentially through the photovoltaic inverters in the first group of reactive power regulation; after each photovoltaic inverter in the first group of reactive power regulation has been regulated, re-determine if a voltage limit violation has occurred; if so, proceed to the next photovoltaic inverter. After the photovoltaic inverter in the first group of reactive power regulation is regulated, if the voltage over-limit still exists, the voltage is adjusted sequentially by the charging power of the energy storage devices in the first group of active power regulation. After each energy storage device in the first group of active power regulation is regulated, the voltage over-limit is re-evaluated. If it is, the process continues to the next energy storage device. If the voltage over-limit regulation is completed based on the energy storage devices in the first group of active power regulation, the regulation action ends.

[0006] By adopting the above technical solution, when the voltage exceeds the limit, the reactive power of the photovoltaic inverter is used first for regulation, and then the active power of the energy storage device is used for regulation. By using the low-cost reactive power regulation first group and then the active power regulation first group, the regulation cost is reduced and the economic benefits are significantly improved.

[0007] Optionally, before determining whether a voltage limit violation has occurred, the method further includes: obtaining the unit voltage regulation cost of each photovoltaic inverter based on the regulation capability and regulation cost of the photovoltaic inverter in the reactive power regulation process in the photovoltaic inverter system; sorting all photovoltaic inverters from low to high according to the obtained unit voltage regulation cost to obtain the first inverter regulation device to the Nth inverter regulation device; classifying photovoltaic inverters with a unit voltage regulation cost not greater than a first preset value into the first reactive power regulation group; classifying photovoltaic inverters with a unit regulation cost greater than the first preset value but not greater than the second preset value into the second reactive power regulation group; and classifying the remaining photovoltaic inverters into the third reactive power regulation group. The unit voltage regulation cost of each energy storage device is obtained based on the regulation capability and regulation cost of the energy storage device in the photovoltaic inverter system during the active power regulation process. All energy storage devices are sorted from low to high according to the obtained unit voltage regulation cost to obtain the first energy storage regulation device to the Mth energy storage regulation device. Energy storage devices with unit voltage regulation costs not greater than the first preset value are classified into the first group of active power regulation. Energy storage devices with unit regulation costs greater than the first preset value but not greater than the second preset value are classified into the second group of active power regulation. The remaining energy storage devices are classified into the third group of active power regulation.

[0008] Optionally, if the voltage exceeds the limit after the photovoltaic inverter in the first group of reactive power regulation has been regulated, the voltage is then adjusted sequentially through the photovoltaic inverter in the second group of reactive power regulation. If the voltage exceeds the limit after the photovoltaic inverter in the second group of reactive power regulation has been regulated, the regulation action ends. If the voltage exceeds the limit after the photovoltaic inverter in the second group of reactive power regulation has been regulated, the voltage is then adjusted sequentially through the charging power of the energy storage device in the second group of active power regulation.

[0009] Optionally, the unit voltage regulation cost of each photovoltaic inverter is obtained based on the regulation capability and regulation cost of the photovoltaic inverter in the reactive power regulation process in the photovoltaic inverter system, including: Obtain performance parameter information of the photovoltaic inverter in the photovoltaic inverter system; the performance parameter information includes reactive power adjustment range, efficiency curve and reactive power output; Based on the efficiency curve and reactive power output of the photovoltaic inverter, the energy consumption under different reactive power regulation states is calculated to obtain the energy cost. Calculate the long-term maintenance cost of photovoltaic inverters based on their lifespan and maintenance cycle. The derived costs are obtained based on the assessment of system performance degradation and equipment losses caused by reactive power regulation. The total regulation cost of each photovoltaic inverter is obtained based on the energy consumption cost, maintenance cost, and derivative costs; and... The unit voltage regulation cost is obtained based on the total regulation cost and reactive power regulation range of the photovoltaic inverter.

[0010] Optionally, the step of obtaining the unit voltage regulation cost of each energy storage device based on the regulation capability and regulation cost of the energy storage device in the photovoltaic inverter system during the active power regulation process includes: Obtain the active power adjustment range of the energy storage device; To obtain the energy consumption cost, depreciation cost, and maintenance cost of energy storage equipment in a photovoltaic inverter system, and thus the usage cost; To obtain the revenue generated when energy storage devices are used for active power regulation; The total regulation cost of each energy storage device is obtained based on the aforementioned usage cost and the aforementioned benefits; The unit voltage regulation cost is obtained based on the total regulation cost of the energy storage device and the active power regulation range.

[0011] Optionally, determine whether a voltage over-limit has occurred, including: The voltage at the photovoltaic grid connection point is monitored in real time using voltage detection equipment in the photovoltaic system. The detected voltage is compared with the set voltage operating range; if it is greater than the set voltage operating range, it is determined that the voltage is out of limit.

[0012] Optionally, the method further includes: collecting system status data during the voltage over-limit period; the system status data includes: photovoltaic power generation data, load data, and photovoltaic system equipment operating status data; The reasons for voltage exceeding limits are determined based on the system status data analysis and recorded in the operation log.

[0013] Secondly, the control method for a photovoltaic inverter system provided in this application adopts the following technical solution.

[0014] A control device for a photovoltaic inverter system, comprising: The first processing module is used to: determine whether a voltage over-limit has occurred; if so, adjust the voltage sequentially through the photovoltaic inverters in the first group of reactive power regulation; after each photovoltaic inverter in the first group of reactive power regulation has been adjusted, re-determine whether a voltage over-limit has occurred; if so, proceed to the next photovoltaic inverter. The second processing module is used for: after the photovoltaic inverter in the first group of reactive power regulation is regulated, if the voltage over-limit still exists, then the voltage is adjusted sequentially by the charging power of the energy storage devices in the first group of active power regulation; after each energy storage device in the first group of active power regulation is regulated, it is re-determined whether the voltage over-limit still exists; if so, it is continued to the next energy storage device; if the voltage over-limit regulation is completed according to the energy storage devices in the first group of active power regulation, then the regulation action ends.

[0015] Thirdly, this application discloses an electronic device including a memory and a processor, wherein the memory stores a computer program that is loaded by the processor and executes any of the methods described above.

[0016] Fourthly, this application discloses a computer-readable storage medium storing a computer program that can be loaded by a processor and execute any of the methods described above. Attached Figure Description

[0017] Figure 1 This is a flowchart of a control method for a photovoltaic inverter system according to an embodiment of this application; Figure 2 This is a system block diagram of a control method for a photovoltaic inverter system according to an embodiment of this application; In the diagram, 201 represents the first processing module; and 202 represents the second processing module. Detailed Implementation

[0018] The following is in conjunction with the appendix Figure 1-2 The present application will be further described with reference to specific embodiments: This application discloses a control method for a photovoltaic inverter system. (Refer to...) Figure 1 As one implementation method of a photovoltaic inverter system control method, the photovoltaic inverter system control method includes the following steps: Step 101: Determine if a voltage over-limit has occurred; if so, adjust the voltage sequentially through the photovoltaic inverters in the first group of reactive power regulation; after each photovoltaic inverter in the first group of reactive power regulation has been regulated, re-determine if a voltage over-limit has occurred; if so, proceed to the next photovoltaic inverter.

[0019] Specifically, voltage exceeding the limit refers to a voltage in a power system exceeding the specified range, which may damage equipment and the system. Photovoltaic inverters are devices used to convert direct current (DC) to alternating current (AC). By adjusting the output voltage of the photovoltaic inverter, the voltage level in the power grid can be controlled. When a voltage exceeding the limit is detected, the system will sequentially adjust the voltage through the photovoltaic inverters in the first reactive power regulation group: first, one photovoltaic inverter in the first reactive power regulation group is selected for adjustment, and the existence of a voltage exceeding the limit is reassessed; if the voltage exceeding the limit still exists, the next photovoltaic inverter is selected for adjustment, until the voltage exceeding the limit problem is resolved or all inverters in the first reactive power regulation group participate in the adjustment.

[0020] Step 102: After the photovoltaic inverter in the first group of reactive power regulation is regulated, if the voltage over-limit still exists, the voltage is adjusted sequentially by the charging power of the energy storage devices in the first group of active power regulation. After each energy storage device in the first group of active power regulation is regulated, it is re-evaluated whether the voltage over-limit still exists. If so, the process continues to the next energy storage device. If the voltage over-limit regulation is completed based on the energy storage devices in the first group of active power regulation, the regulation action ends.

[0021] Specifically, when the voltage limit violation problem persists, the voltage is regulated by adjusting the charging power of the energy storage devices in the first group of active power regulation. After each energy storage device completes its adjustment, the voltage limit violation problem is reassessed. If it persists, the adjustment is moved to the next energy storage device. This process continues until the voltage limit violation problem is resolved or all devices in the first group of active power regulation participate in the adjustment. By using a combination of photovoltaic inverters and energy storage devices, the voltage limit violation problem is effectively solved.

[0022] As a specific implementation of a control method for a photovoltaic inverter system, before determining whether a voltage over-limit has occurred, the method further includes: obtaining the unit voltage regulation cost of each photovoltaic inverter based on the regulation capability and regulation cost of the photovoltaic inverter in the reactive power regulation process; sorting all photovoltaic inverters from low to high according to the obtained unit voltage regulation cost to obtain the first inverter regulation device to the Nth inverter regulation device; classifying photovoltaic inverters with a unit voltage regulation cost not greater than a first preset value into the first reactive power regulation group; classifying photovoltaic inverters with a unit regulation cost greater than the first preset value but not greater than a second preset value into the second reactive power regulation group; and classifying the remaining photovoltaic inverters into the third reactive power regulation group. The unit voltage regulation cost of each energy storage device is obtained based on the regulation capability and regulation cost of the energy storage device in the photovoltaic inverter system during the active power regulation process. All energy storage devices are sorted from low to high according to the obtained unit voltage regulation cost to obtain the first energy storage regulation device to the Mth energy storage regulation device. Energy storage devices with unit voltage regulation costs not greater than the first preset value are classified into the first group of active power regulation. Energy storage devices with unit regulation costs greater than the first preset value but not greater than the second preset value are classified into the second group of active power regulation. The remaining energy storage devices are classified into the third group of active power regulation.

[0023] Specifically, before determining whether a voltage limit violation has occurred, the unit voltage regulation cost of each photovoltaic inverter in the photovoltaic inverter system is calculated based on its regulation capability and cost during reactive power regulation. This calculation is used to assess the cost-effectiveness of each inverter in reactive power regulation. Next, based on the calculated unit voltage regulation cost, all photovoltaic inverters are ranked from low to high, resulting in inverters ranked from first to Nth. This clearly demonstrates the relative merits of each inverter in reactive power regulation. Then, photovoltaic inverters with unit voltage regulation costs not exceeding a first preset value are categorized into the first group of reactive power regulators. These inverters have lower costs in reactive power regulation and can be considered as priority options. Similarly, photovoltaic inverters with unit regulation costs exceeding the first preset value but not exceeding the second preset value are categorized into the second group of reactive power regulators. These inverters have higher costs in reactive power regulation but are still worth considering. Finally, the remaining photovoltaic inverters are categorized into the third group of reactive power regulators. A similar process is applied to energy storage devices. The above classification and sorting helps to optimize the operation of photovoltaic inverter systems, improve energy efficiency, and reduce operating costs.

[0024] As a specific implementation of a control method for a photovoltaic inverter system, if the voltage exceeds the limit after the photovoltaic inverter in the first group of power regulation is regulated, the voltage is then adjusted sequentially through the photovoltaic inverter in the second group of reactive power regulation; if the voltage exceeds the limit after the photovoltaic inverter in the second group of reactive power regulation is regulated, the regulation action ends; if the voltage exceeds the limit after the photovoltaic inverter in the second group of reactive power regulation is regulated, the voltage is then adjusted sequentially through the charging power of the energy storage device in the second group of active power regulation.

[0025] As a specific implementation method of a photovoltaic inverter system control method, the unit voltage regulation cost of each photovoltaic inverter is obtained based on the regulation capability and regulation cost of the photovoltaic inverter in the reactive power regulation process, including: Obtain performance parameter information of the photovoltaic inverter in the photovoltaic inverter system; the performance parameter information includes reactive power adjustment range, efficiency curve and reactive power output; Based on the efficiency curve and reactive power output of the photovoltaic inverter, the energy consumption under different reactive power regulation states is calculated to obtain the energy cost. Calculate the long-term maintenance cost of photovoltaic inverters based on their lifespan and maintenance cycle. The derived costs are obtained based on the assessment of system performance degradation and equipment losses caused by reactive power regulation. The total regulation cost of each photovoltaic inverter is obtained based on the energy consumption cost, maintenance cost, and derivative costs; and... The unit voltage regulation cost is obtained based on the total regulation cost and reactive power regulation range of the photovoltaic inverter.

[0026] As one implementation method of a photovoltaic inverter system control method, the step of obtaining the unit voltage regulation cost of each energy storage device based on the regulation capability and regulation cost of the energy storage device in the active power regulation process of the photovoltaic inverter system includes: Obtain the active power adjustment range of the energy storage device; To obtain the energy consumption cost, depreciation cost, and maintenance cost of energy storage equipment in a photovoltaic inverter system, and thus the usage cost; To obtain the revenue generated when energy storage devices are used for active power regulation; The total regulation cost of each energy storage device is obtained based on the aforementioned usage cost and the aforementioned benefits; The unit voltage regulation cost is obtained based on the total regulation cost of the energy storage device and the active power regulation range.

[0027] As one implementation method of a control method for a photovoltaic inverter system, determining whether a voltage over-limit has occurred includes: The voltage at the photovoltaic grid connection point is monitored in real time using voltage detection equipment in the photovoltaic system. The detected voltage is compared with the set voltage operating range; if it is greater than the set voltage operating range, it is determined that the voltage is out of limit.

[0028] As one embodiment of a control method for a photovoltaic inverter system, the method further includes: collecting system status data during voltage over-limit periods; the system status data includes: photovoltaic power generation data, load data, and photovoltaic system equipment operating status data; The reasons for voltage exceeding limits are determined based on the system status data analysis and recorded in the operation log.

[0029] This application also discloses a control device as a photovoltaic inverter system, including: The first processing module 201 is used to: determine whether a voltage over-limit has occurred; if so, adjust the voltage sequentially through the photovoltaic inverters in the first group of reactive power regulation; after each photovoltaic inverter in the first group of reactive power regulation has been adjusted, re-determine whether a voltage over-limit has occurred; if so, proceed to the next photovoltaic inverter. The second processing module 202 is used for: after the photovoltaic inverter in the first group of reactive power regulation is regulated, if the voltage over-limit still exists, then the voltage is adjusted sequentially by the charging power of the energy storage devices in the first group of active power regulation; after each energy storage device in the first group of active power regulation is regulated, it is re-determined whether the voltage over-limit exists; if so, it is continued to the next energy storage device; if the voltage over-limit regulation is completed according to the energy storage devices in the first group of active power regulation, then the regulation action is terminated.

[0030] This is one implementation method of a control method for a photovoltaic inverter system.

[0031] This application also discloses an electronic device.

[0032] Specifically, the device includes a memory and a processor, the memory storing a computer program that can be loaded by the processor and executed for any of the aforementioned control methods of the photovoltaic inverter system.

[0033] This application also discloses a computer-readable storage medium. Specifically, the computer-readable storage medium stores a computer program that can be loaded by a processor and executed as a control method for any of the photovoltaic inverter systems described above. The computer-readable storage medium includes, for example, various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0034] It should be noted that the above embodiments are only used to illustrate this application and are not intended to limit the technical solutions described in this application. Although this specification has described this application in detail with reference to the above embodiments, those skilled in the art should understand that they can still make modifications or equivalent substitutions to this application. All technical solutions and improvements that do not depart from the spirit and scope of this application should be covered within the scope of the claims of this application.

Claims

1. A control method for a photovoltaic inverter system, characterized in that, include: Determine if a voltage over-limit has occurred; If so, the voltage is adjusted sequentially through the photovoltaic inverters in the first group of reactive power regulation. After each photovoltaic inverter in the first group of reactive power regulation has been regulated, the voltage over-limit is re-evaluated; if so, the process continues to the next photovoltaic inverter. After the photovoltaic inverter in the first group of reactive power regulation is regulated, if the voltage over-limit still exists, the voltage is regulated sequentially by the charging power of the energy storage devices in the first group of active power regulation. After each energy storage device in the first group of active power regulation is regulated, it is re-evaluated whether the voltage over-limit still exists. If it does, the process continues to the next energy storage device. If the energy storage device in the first group of active power regulation completes the voltage over-limit regulation, the regulation action will end.

2. The control method for a photovoltaic inverter system according to claim 1, characterized in that, Before determining whether a voltage limit violation has occurred, the method further includes: obtaining the unit voltage regulation cost of each photovoltaic inverter based on the regulation capability and regulation cost of the photovoltaic inverter in the reactive power regulation process in the photovoltaic inverter system; sorting all photovoltaic inverters from low to high according to the obtained unit voltage regulation cost to obtain the first inverter regulation device to the Nth inverter regulation device; classifying photovoltaic inverters with a unit voltage regulation cost not greater than a first preset value into the first group of reactive power regulation; classifying photovoltaic inverters with a unit regulation cost greater than the first preset value but not greater than the second preset value into the second group of reactive power regulation; and classifying the remaining photovoltaic inverters into the third group of reactive power regulation. The unit voltage regulation cost of each energy storage device is obtained based on the regulation capability and regulation cost of the energy storage device in the photovoltaic inverter system during the active power regulation process. All energy storage devices are sorted from low to high according to the obtained unit voltage regulation cost to obtain the first energy storage regulation device to the Mth energy storage regulation device. Energy storage devices with unit voltage regulation costs not greater than the first preset value are classified into the first group of active power regulation. Energy storage devices with unit regulation costs greater than the first preset value but not greater than the second preset value are classified into the second group of active power regulation. The remaining energy storage devices are classified into the third group of active power regulation.

3. The control method for a photovoltaic inverter system according to claim 2, characterized in that, If the voltage exceeds the limit after the photovoltaic inverter in the first group of reactive power regulation is regulated, the voltage will be adjusted sequentially through the photovoltaic inverter in the second group of reactive power regulation. If the voltage exceeds the limit after the photovoltaic inverter in the second group of reactive power regulation is regulated, the regulation action will end. If the voltage exceeds the limit after the photovoltaic inverter in the second group of reactive power regulation is regulated, the voltage will be adjusted sequentially through the charging power of the energy storage device in the second group of active power regulation.

4. The control method for a photovoltaic inverter system according to claim 3, characterized in that, The unit voltage regulation cost of each photovoltaic inverter is obtained based on the regulation capability and regulation cost of the photovoltaic inverter in the reactive power regulation process in the photovoltaic inverter system, including: Obtain performance parameter information of the photovoltaic inverter in the photovoltaic inverter system; the performance parameter information includes reactive power adjustment range, efficiency curve and reactive power output; Based on the efficiency curve and reactive power output of the photovoltaic inverter, the energy consumption under different reactive power regulation states is calculated to obtain the energy cost. Calculate the long-term maintenance cost of photovoltaic inverters based on their lifespan and maintenance cycle. The derived costs are obtained based on the assessment of system performance degradation and equipment losses caused by reactive power regulation. The total regulation cost of each photovoltaic inverter is obtained based on the energy consumption cost, maintenance cost, and derivative costs; and... The unit voltage regulation cost is obtained based on the total regulation cost and reactive power regulation range of the photovoltaic inverter.

5. The control method for a photovoltaic inverter system according to claim 4, characterized in that, The unit voltage regulation cost of each energy storage device is obtained based on the regulation capability and regulation cost of the energy storage device in the photovoltaic inverter system during the active power regulation process, including: Obtain the active power adjustment range of the energy storage device; To obtain the energy consumption cost, depreciation cost, and maintenance cost of energy storage equipment in a photovoltaic inverter system, and thus the usage cost; To obtain the revenue generated when energy storage devices are used for active power regulation; The total regulation cost of each energy storage device is obtained based on the aforementioned usage cost and the aforementioned benefits; The unit voltage regulation cost is obtained based on the total regulation cost of the energy storage device and the active power regulation range.

6. The control method for a photovoltaic inverter system according to claim 5, characterized in that, Determining whether a voltage over-limit has occurred includes: The voltage at the photovoltaic grid connection point is monitored in real time using voltage detection equipment in the photovoltaic system. The detected voltage is compared with the set voltage operating range; if it is greater than the set voltage operating range, it is determined that the voltage is out of limit.

7. The control method for a photovoltaic inverter system according to claim 6, characterized in that, The method further includes: collecting system status data during voltage over-limit periods; the system status data includes: photovoltaic power generation data, load data, and photovoltaic system equipment operating status data; The reasons for voltage exceeding limits are determined based on the system status data analysis and recorded in the operation log.

8. A control device for a photovoltaic inverter system, characterized in that, include: The first processing module is used to: determine whether a voltage over-limit has occurred; If so, the voltage is adjusted sequentially through the photovoltaic inverters in the first group of reactive power regulation. After each photovoltaic inverter in the first group of reactive power regulation has been regulated, the voltage over-limit is re-evaluated; if so, the process continues to the next photovoltaic inverter. The second processing module is used for: after the photovoltaic inverter in the first group of reactive power regulation is regulated, if the voltage over-limit still exists, the voltage is adjusted sequentially by the charging power of the energy storage devices in the first group of active power regulation; after each energy storage device in the first group of active power regulation is regulated, the voltage over-limit is re-determined; if so, the process continues to the next energy storage device. If the energy storage device in the first group of active power regulation completes the voltage over-limit regulation, the regulation action will end.

9. An electronic device, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program that is loaded and executed by the processor according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, It stores a computer program that can be loaded by a processor and executed as described in any one of claims 1 to 7.

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