Inverter power control method and device

Abstract

The invention discloses an inverter power control method and device which are applied to a controller of an inverter power control system, the controller is in communication connection with an inverter, a sampler and a power grid in the inverter power control system, and the sampler is further electrically connected with the inverter and the power grid. The method comprises the following steps: controlling a sampler to collect the power grid voltage of a grid-connected node between an inverter and a power grid in real time; comparing the power grid voltage with a preset voltage threshold value to obtain a comparison result; adjusting the power value of the inverter according to the comparison result and a preset curve to obtain a target power value; and controlling the inverter to control the current according to the target power value so as to output the current to the power grid. By implementing the embodiment of the invention, the inverter can still perform continuous grid-connected power generation at the maximum allowable output current under the condition that the voltage of the power grid is relatively low, and the use safety is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to an inverter power control method and device. Background Art

[0002] At present, for grid-connected photovoltaic power generation systems, the inverter converts the direct current of the solar panel into alternating current and feeds it into the grid. The inverter is an important component of the grid-connected photovoltaic power generation system. However, in the actual application of the inverter, the grid voltage is often lower than the rated voltage of the inverter itself. Considering that the power of the photovoltaic panel on the DC side remains relatively unchanged, the lower the grid voltage, the greater the inverter grid-connected current. When the inverter grid-connected current increases to the maximum allowable output current inherent to the inverter, the AC grid-connected power is limited, and the inverter is still tracking the maximum power point of the photovoltaic panel, so that the output power of the photovoltaic panel exceeds the corresponding inverter AC grid-connected power, resulting in serious faults such as excessive inverter bus energy and bus overvoltage fault shutdown in a short period of time.

[0003] Therefore, when the grid voltage is lower and the inverter grid-connected current increases to the maximum allowable output current inherent in the inverter, the output power of the photovoltaic panel exceeds the corresponding inverter AC grid-connected power, resulting in serious faults such as excessive inverter bus energy and bus overvoltage fault shutdown in a short period of time, resulting in low safety. Summary of the invention

[0004] The embodiments of the present invention provide an inverter power control method and device, which are intended to solve the problem in the prior art that when the grid voltage is lower and the inverter grid-connected current increases to the maximum allowable output current inherent in the inverter, the output power of the photovoltaic panel exceeds the corresponding inverter AC grid-connected power, resulting in serious faults such as excessive inverter bus energy and bus overvoltage fault shutdown in a short period of time, thereby causing low safety.

[0005] In order to solve the above problems, in a first aspect, an embodiment of the present invention provides an inverter power control method, which is applied to a controller of an inverter power control system, wherein the controller is communicatively connected with an inverter, a sampler and a power grid in the inverter power control system, and the sampler is also electrically connected with the inverter and the power grid; the inverter power control method comprises:

[0006] Controlling the sampler to collect the grid voltage of the grid-connected node between the inverter and the grid in real time;

[0007] Comparing the grid voltage with a preset voltage threshold to obtain a comparison result;

[0008] Adjusting the power value of the inverter according to the comparison result and a preset curve to obtain a target power value;

[0009] The inverter is controlled to control the current according to the target power value so as to output the current to the power grid.

[0010] In a second aspect, an embodiment of the present application provides an inverter power control device, which is applied to a controller of an inverter power control system, wherein the controller is communicatively connected to an inverter, a sampler, and a power grid in the inverter power control system, and the sampler is also electrically connected to the inverter and the power grid; the inverter power control device includes:

[0011] A collection unit, used for controlling the sampler to collect the grid voltage of the grid-connected node between the inverter and the grid in real time;

[0012] A comparison unit, used for comparing the grid voltage with a preset voltage threshold to obtain a comparison result;

[0013] An adjustment unit, configured to adjust the power value of the inverter to obtain a target power value according to the comparison result and a preset curve;

[0014] A control unit is used to control the inverter to control the current according to the target power value so as to output the current to the power grid.

[0015] The embodiment of the present invention provides an inverter power control method and device, which is applied to the controller of the inverter power control, wherein the controller is in communication connection with the inverter, sampler and power grid in the inverter power control system, and the sampler is also in electrical connection with the inverter and the power grid; the inverter power control method includes: controlling the sampler to collect the grid voltage of the grid-connected node between the inverter and the power grid in real time; comparing the grid voltage with a preset voltage threshold to obtain a comparison result; adjusting the power value of the inverter according to the comparison result and the preset curve to obtain a target power value; adjusting the power value of the inverter according to the comparison result and the preset curve to obtain a target power value; controlling the inverter to control the current according to the target power value to output to the power grid. It can be seen that by implementing the embodiment of the present invention, it is achieved that the inverter can continue to generate electricity with the maximum allowable output current when the grid voltage is low, thereby improving the safety of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0017] Figure 1A schematic diagram of a flow chart of an inverter power control method provided by an embodiment of the present invention;

[0018] Figure 2 A schematic block diagram of an inverter power control device provided by an embodiment of the present invention;

[0019] Figure 3 A schematic diagram of a scenario of an inverter power control method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0022] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0023] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0024] The present invention provides a method and device for controlling inverter power. Figure 3 , Figure 3A scenario diagram of the inverter power control method provided by an embodiment of the present invention. The inverter power control method is applied to a controller 11 of an inverter power control system 10, and the controller 11 is communicatively connected with an inverter 12, a sampler 13, and a power grid 14 in the inverter power control system 10, that is, the controller 11 controls the inverter power control process; the inverter 12 is also electrically connected to the power grid 14, and the sampler 13 is also electrically connected to both the inverter 12 and the power grid 14. Specifically, the inverter power control system 10 includes a controller 11, an inverter 12, a sampler 13, a power grid 14, and a photovoltaic panel 15, and the photovoltaic panel 15 is electrically connected to the inverter 12 and the controller 11.

[0025] It should be noted that the controller 11 may be disposed in the inverter 12 , or may be disposed separately from the inverter 12 .

[0026] See also Figure 1 , Figure 1 A schematic flow chart of an inverter power control method provided by an embodiment of the present invention. An inverter power control method is provided by an embodiment of the present invention, and the inverter power control method includes the following steps S110-S140.

[0027] S110, controlling the sampler to collect the grid voltage of the grid-connected node between the inverter and the grid in real time.

[0028] In this embodiment, the grid-connected node is a connection point between the inverter and the grid, that is, the number of the grid-connected nodes is 1; the controller controls the sampler to collect the grid voltage of the grid-connected node between the inverter and the grid in real time.

[0029] The inverter includes a DCDC (direct current to direct current) boost unit and a DCAC (direct current to alternating current) inverter unit, the DCDC boost unit is communicatively connected to both the photovoltaic panel and the DCAC inverter unit, and the DCAC inverter unit is also connected to the power grid; the DCDC boost unit converts the DC power input from the photovoltaic panel into a DC power of a target voltage, and the target voltage refers to the voltage required by the DCAC inverter unit; the DCAC inverter unit converts the DC power of the target voltage into an AC power to be input into the power grid.

[0030] The rated voltage of the inverter is one of the basic technical specifications on the AC side, and corresponds to the grid voltage level of the grid-connected node of the inverter. For example: for a three-phase grid, if the grid-connected voltage level of the grid-connected node is a line voltage of 400Vac, the rated voltage of the inverter is 400Vac; if the grid-connected voltage level of the grid-connected node is a line voltage of 800Vac, the rated voltage of the inverter is 800Vac. The maximum allowable output current and the maximum allowable output power are other basic technical specifications on the AC side of the inverter, representing the power output capacity of the inverter. The larger the maximum allowable output current and the maximum allowable output power, the greater the power that the inverter can invert. Due to the limitations of the hardware conditions of the inverter, for the same type of inverter, the maximum allowable output current and the maximum allowable output power are fixed.

[0031] In the actual application of photovoltaic inverters, the grid voltage often appears to be lower than the rated voltage of the inverter itself. Considering that the power of the photovoltaic panel on the DC side remains relatively unchanged, the lower the grid voltage, the greater the inverter grid-connected current. When the inverter grid-connected current increases to the maximum allowable output current inherent to the inverter, the AC grid-connected power is limited, and the DCDC boost unit is still tracking the maximum output power point of the photovoltaic panel, so that the photovoltaic panel output power (that is, the DCDC boost unit input power) exceeds the corresponding inverter AC grid-connected power, resulting in serious faults such as excessive inverter bus energy and bus overvoltage fault shutdown in a short period of time, resulting in low safety.

[0032] In one embodiment, the grid voltage includes: a grid line voltage of a three-phase three-wire system of a three-phase grid, a grid line voltage or a phase voltage of a three-phase four-wire system of a three-phase grid, and a phase voltage of a single-phase grid.

[0033] In this embodiment, the grid voltage may include a three-phase three-wire grid line voltage, a three-phase four-wire grid line voltage or phase voltage, and a single-phase grid phase voltage, etc. Accordingly, the grid may be a three-phase grid, a single-phase grid, etc.

[0034] Through the above embodiments, it can be known that the grid voltage can include the grid line voltage of the three-phase three-wire system of the three-phase grid, the grid line voltage or phase voltage of the three-phase four-wire system of the three-phase grid, and the phase voltage of the single-phase grid, etc., to ensure the adaptability of the grid and thus improve the applicability.

[0035] S120: Compare the grid voltage with a preset voltage threshold to obtain a comparison result.

[0036] In this embodiment, the controller compares the grid voltage with a preset voltage threshold to obtain a comparison result; specifically, the comparison result includes two results, namely, the comparison result is that the grid voltage is less than the voltage threshold, and the comparison result is that the grid voltage is greater than or equal to the voltage threshold. It should be noted that the present invention is mainly aimed at the method of low grid voltage, so it mainly considers the case where the comparison result is that the grid voltage is less than the voltage threshold; and when the comparison result is that the grid voltage is greater than or equal to the voltage threshold, the inverter maintains the original power, current, etc. to continue to output to the grid voltage normally.

[0037] S130: adjusting the power value of the inverter according to the comparison result and a preset curve to obtain a target power value.

[0038] In this embodiment, the controller adjusts the power value of the inverter according to the comparison result and the preset curve to obtain the target power value.

[0039] In one embodiment, before adjusting the power value of the inverter according to the comparison result and the preset curve to obtain the target power value, the method further includes:

[0040] Obtaining the maximum allowable output current of the inverter;

[0041] The preset curve is constructed according to the maximum allowable output current and the grid voltage.

[0042] In this embodiment, the controller obtains the maximum allowable output current of the inverter, and constructs the preset curve according to the maximum allowable output current and the grid voltage. The preset formula is a linear function of y=kx+b, y is Sout (target power value), x is Ugrid (grid voltage), and k and b are constants.

[0043] The maximum allowable output current refers to a performance parameter of the inverter, which can be obtained through testing.

[0044] Through the above embodiments, it can be known that the preset curve is constructed according to the maximum allowable output current and the grid voltage to improve the accuracy of data so as to perform targeted processing according to the preset curve later.

[0045] In one embodiment, adjusting the power value of the inverter according to the comparison result and a preset curve to obtain a target power value includes:

[0046] When the comparison result is that the grid voltage is less than the voltage threshold, the target power value is obtained in the preset curve according to the grid voltage.

[0047] In this embodiment, when the comparison result is that the grid voltage is less than the voltage threshold, the controller obtains the target power value in the preset curve based on the grid voltage; specifically, the target power value corresponding to the grid voltage is directly obtained in the preset curve based on the collected grid voltage.

[0048] Furthermore, after the grid voltage is compared with a preset voltage threshold to obtain a comparison result, the method may further include:

[0049] The output current of the photovoltaic panel is adjusted according to the comparison result, so as to adjust the power value of the inverter to obtain the target power value.

[0050] Specifically, adjusting the output current of the photovoltaic panel according to the comparison result to adjust the power value of the inverter to obtain the target power value includes: when the comparison result is that the grid voltage is less than the voltage threshold, reducing the output current of the photovoltaic panel to reduce the output power of the photovoltaic panel, and then adjusting the power value of the inverter to obtain the target power value.

[0051] It should be noted that the output current of the photovoltaic panel is the current input to the DCDC boost unit of the inverter.

[0052] Through the above embodiments, it can be known that by using the grid voltage to obtain the corresponding target power value in the preset curve, the target power value is obtained based on the grid voltage and the preset curve to ensure data accuracy, thereby improving safety of use.

[0053] S140: Control the inverter to control the current according to the target power value to output the current to the power grid.

[0054] In this embodiment, the controller controls the inverter to control the current according to the target power value to output to the power grid, so as to solve the problem of excessive inverter bus energy and bus overvoltage fault shutdown in a short period of time caused by low voltage at the inverter grid-connected point, grid-connected current increasing to the maximum allowable output current inherent in the inverter, and AC grid-connected power being limited, and the output power of the photovoltaic panel exceeding the AC grid-connected power of the corresponding inverter. This allows the inverter to continue to connect to the grid for power generation at the maximum allowable output current when the grid voltage is low, thereby improving safety of use.

[0055] Further, controlling the inverter to control the current according to the target power value to output to the power grid includes:

[0056] Tracking the maximum output power of the photovoltaic panel using a preset algorithm and the inverter;

[0057] When the maximum output power is greater than the target power value, a power limiting action is performed to reduce the output power of the photovoltaic panel to a preset range of the target power value; or

[0058] When the maximum output power is less than or equal to the target power value, the preset algorithm and the inverter are used to continue tracking the maximum output power of the photovoltaic panel to maintain the maximum output power operation of the photovoltaic panel.

[0059] In this embodiment, the preset algorithm may be a MPPT (Maximum Power Point Tracking, abbreviated as MPPT) algorithm; and the preset algorithm is executed in the DCDC boost unit of the inverter.

[0060] The controller uses the preset algorithm and the inverter to track the maximum output power of the photovoltaic panel; when the maximum output power is greater than the target power value, the controller performs a power limiting action to reduce the output power of the photovoltaic panel to a preset interval near the target power value; or when the maximum output power is less than or equal to the target power value, the controller continues to track the maximum output power of the photovoltaic panel using the preset algorithm and the inverter to maintain the maximum output power operation of the photovoltaic panel.

[0061] The power limiting action is performed to reduce the output power of the photovoltaic panel to a preset interval near the target power value, specifically by increasing the input voltage and then significantly reducing the current, thereby achieving power reduction.

[0062] In one embodiment, the voltage threshold is less than or equal to the rated voltage of the inverter.

[0063] In this embodiment, the voltage threshold may be equal to the rated voltage. In this case, once the grid voltage is lower than the rated voltage of the inverter, the inverter starts to reduce the target power value to perform a power limiting action.

[0064] The controller can directly obtain the rated voltage of the inverter, and the rated voltage of the inverter is one of the basic technical specifications of the AC side.

[0065] Through the above embodiments, it can be known that the voltage threshold is less than or equal to the rated voltage of the inverter. Therefore, the inverter can continue to operate stably in a lower grid voltage range, have a wider grid voltage adaptation range and grid adaptability, thereby improving applicability and safety of use.

[0066] In summary, the grid voltage of the grid-connected node between the inverter and the grid is collected in real time by controlling the sampler, and the grid voltage is compared with the preset voltage threshold to obtain the comparison result, so as to adjust the power value of the inverter according to the comparison result and the preset curve to obtain the target power value. Therefore, it is possible to solve the problem that the inverter grid-connected point voltage is low, the grid-connected current increases to the maximum allowable output current inherent in the inverter, and the AC grid-connected power is limited, and the output power of the photovoltaic panel exceeds the AC grid-connected power of the corresponding inverter, resulting in the inverter bus energy being too high in a short time and the bus overvoltage fault shutdown, so that the inverter can still continue to connect to the grid and generate electricity with the maximum allowable output current when the grid voltage is low, thereby improving the safety of use; at the same time, it is possible to enable the inverter to operate continuously and stably in a lower grid voltage range, with a wider grid voltage adaptation range and grid adaptability, ensuring applicability, thereby improving the safety of use.

[0067] See also Figure 2 , Figure 2 Schematic block diagram of an inverter power control device 100 provided in an embodiment of the present invention. Figure 2 As shown, an embodiment of the present invention provides an inverter power control device 100 for implementing the method as described above, which is applied to a controller of an inverter power control system. The controller is communicatively connected with an inverter, a sampler and a power grid in the inverter power control system, that is, the controller controls the inverter power control process; the sampler is also electrically connected with the inverter and the power grid.

[0068] like Figure 2 As shown, the inverter power control device 100 includes:

[0069] The collection unit 110 is used to control the sampler to collect the grid voltage of the grid-connected node between the inverter and the grid in real time;

[0070] A comparison unit 120, configured to compare the grid voltage with a preset voltage threshold to obtain a comparison result;

[0071] An adjusting unit 130, configured to adjust the power value of the inverter to obtain a target power value according to the comparison result and a preset curve;

[0072] The control unit 140 is used to control the inverter to control the current according to the target power value so as to output the current to the power grid.

[0073] In some embodiments, when the adjustment unit 130 performs the step of adjusting the power value of the inverter according to the comparison result and the preset curve to obtain the target power value, it is specifically used to:

[0074] When the comparison result is that the grid voltage is less than the voltage threshold, the target power value is obtained in the preset curve according to the grid voltage.

[0075] In this embodiment, when the comparison result is that the grid voltage is less than the voltage threshold, the controller obtains the target power value in the preset curve based on the grid voltage; specifically, the target power value corresponding to the grid voltage is directly obtained in the preset curve based on the collected grid voltage.

[0076] Furthermore, after the grid voltage is compared with a preset voltage threshold to obtain a comparison result, the method may further include:

[0077] The output current of the photovoltaic panel is adjusted according to the comparison result, so as to adjust the power value of the inverter to obtain the target power value.

[0078] Specifically, adjusting the output current of the photovoltaic panel according to the comparison result to adjust the power value of the inverter to obtain the target power value includes: when the comparison result is that the grid voltage is less than the voltage threshold, reducing the output current of the photovoltaic panel to reduce the output power of the photovoltaic panel, and then adjusting the power value of the inverter to obtain the target power value.

[0079] It should be noted that the output current of the photovoltaic panel is the current input to the DCDC boost unit of the inverter.

[0080] Through the above embodiments, it can be known that by using the grid voltage to obtain the corresponding target power value in the preset curve, the target power value is obtained based on the grid voltage and the preset curve to ensure data accuracy, thereby improving safety of use.

[0081] Further, after obtaining the target power value in the preset curve according to the grid voltage, the method further includes:

[0082] The inverter is controlled to control the current according to the target power value so as to output the current to the power grid.

[0083] In this embodiment, the controller controls the inverter to control the current according to the target power value to output to the power grid, so as to solve the problem of excessive inverter bus energy and bus overvoltage fault shutdown in a short period of time caused by low voltage at the inverter grid-connected point, grid-connected current increasing to the maximum allowable output current inherent in the inverter, and AC grid-connected power being limited, and the output power of the photovoltaic panel exceeding the AC grid-connected power of the corresponding inverter. This allows the inverter to continue to connect to the grid for power generation at the maximum allowable output current when the grid voltage is low, thereby improving safety of use.

[0084] Further, after obtaining the target power value in the preset curve according to the grid voltage, the method further includes:

[0085] Tracking the maximum output power of the photovoltaic panel using a preset algorithm and the inverter;

[0086] When the maximum output power is greater than the target power value, a power limiting action is performed to reduce the output power of the photovoltaic panel to a preset interval near the target power value; or

[0087] When the maximum output power is less than or equal to the target power value, the preset algorithm and the inverter are used to continue tracking the maximum output power of the photovoltaic panel to maintain the maximum output power operation of the photovoltaic panel.

[0088] In this embodiment, the preset algorithm may be a MPPT (Maximum Power Point Tracking, abbreviated as MPPT) algorithm; and the preset algorithm is executed in the DCDC boost unit of the inverter.

[0089] The controller uses the preset algorithm and the inverter to track the maximum output power of the photovoltaic panel; when the maximum output power is greater than the target power value, the controller performs a power limiting action to reduce the output power of the photovoltaic panel to a preset interval of the target power value; or when the maximum output power is less than or equal to the target power value, the controller continues to track the maximum output power of the photovoltaic panel using the preset algorithm and the inverter to maintain the maximum output power operation of the photovoltaic panel.

[0090] The power limiting action is performed to reduce the output power of the photovoltaic panel to a preset range of the target power value, specifically by increasing the input voltage and then significantly reducing the current, thereby achieving power reduction.

[0091] In some embodiments, before executing the step of adjusting the power value of the inverter according to the comparison result and the preset curve to obtain the target power value, the adjustment unit 130 is further specifically configured to:

[0092] Obtaining the maximum allowable output current of the inverter;

[0093] The preset curve is constructed according to the maximum allowable output current and the grid voltage.

[0094] In some embodiments, the grid voltage includes: a grid line voltage of a three-phase three-wire three-phase grid, a grid line voltage or a phase voltage of a three-phase four-wire three-phase grid, and a phase voltage of a single-phase grid.

[0095] In this embodiment, the grid voltage may include a three-phase three-wire grid line voltage, a three-phase four-wire grid line voltage or phase voltage, and a single-phase grid phase voltage, etc. Accordingly, the grid may be a three-phase grid, a single-phase grid, etc.

[0096] Through the above embodiments, it can be known that the grid voltage can include the grid line voltage of the three-phase three-wire system of the three-phase grid, the grid line voltage or phase voltage of the three-phase four-wire system of the three-phase grid, and the phase voltage of the single-phase grid, etc., to ensure the adaptability of the grid and thus improve the applicability.

[0097] In some embodiments, it is also specifically used that: the voltage threshold is less than or equal to the rated voltage of the inverter.

[0098] In this embodiment, the voltage threshold may be equal to the rated voltage. In this case, once the grid voltage is lower than the rated voltage of the inverter, the inverter starts to reduce the target power value to perform a power limiting action.

[0099] The controller can directly obtain the rated voltage of the inverter.

[0100] Through the above embodiments, it can be known that the voltage threshold is less than or equal to the rated voltage of the inverter. Therefore, the inverter can continue to operate stably in a lower grid voltage range, have a wider grid voltage adaptation range and grid adaptability, thereby improving applicability and safety of use.

[0101] It should be noted that those skilled in the art can clearly understand that the specific implementation process of the above-mentioned device and each user can refer to the corresponding description in the aforementioned method embodiment, and for the convenience and brevity of description, it will not be repeated here.

[0102] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, and the division of the units is only a logical function division, and there may be other division methods in actual implementation. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the devices and units described above can refer to the corresponding process in the aforementioned method embodiments, and will not be repeated here.

[0103] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An inverter power control method, characterized in that: In a controller applied to an inverter power control system, the controller is communicatively connected with an inverter, a sampler and a power grid in the inverter power control system, and the sampler is also electrically connected with the inverter and the power grid; The inverter power control method comprises: Controlling the sampler to collect the grid voltage of the grid-connected node between the inverter and the grid in real time; Comparing the grid voltage with a preset voltage threshold to obtain a comparison result; Adjusting the power value of the inverter according to the comparison result and a preset curve to obtain a target power value; The inverter is controlled to control the current according to the target power value so as to output the current to the power grid.

2. The inverter power control method according to claim 1, characterized in that: The step of adjusting the power value of the inverter according to the comparison result and the preset curve to obtain a target power value includes: When the comparison result is that the grid voltage is less than the voltage threshold, the target power value is obtained in the preset curve according to the grid voltage.

3. The inverter power control method according to claim 1, characterized in that: Before adjusting the power value of the inverter according to the comparison result and the preset curve to obtain the target power value, the method further includes: Obtaining the maximum allowable output current of the inverter; The preset curve is constructed according to the maximum allowable output current and the grid voltage.

4. The inverter power control method according to claim 1, characterized in that: The grid voltage includes: a grid line voltage of a three-phase three-wire system of a three-phase grid, a grid line voltage or a phase voltage of a three-phase four-wire system of a three-phase grid, and a phase voltage of a single-phase grid.

5. The inverter power control method according to claim 1, characterized in that: The voltage threshold is less than or equal to the rated voltage of the inverter.

6. An inverter power control device, characterized in that: In a controller applied to an inverter power control system, the controller is communicatively connected with an inverter, a sampler and a power grid in the inverter power control system, and the sampler is also electrically connected with the inverter and the power grid; The inverter power control device comprises: A collection unit, used for controlling the sampler to collect the grid voltage of the grid-connected node between the inverter and the grid in real time; A comparison unit, used for comparing the grid voltage with a preset voltage threshold to obtain a comparison result; An adjustment unit, configured to adjust the power value of the inverter to obtain a target power value according to the comparison result and a preset curve; A control unit is used to control the inverter to control the current according to the target power value so as to output the current to the power grid.

7. The inverter power control device according to claim 6, characterized in that: The step of adjusting the power value of the inverter according to the comparison result and the preset curve to obtain a target power value includes: When the comparison result is that the grid voltage is less than the voltage threshold, the target power value is obtained in the preset curve according to the grid voltage.

8. The inverter power control device according to claim 6, characterized in that: Before adjusting the power value of the inverter according to the comparison result and the preset curve to obtain the target power value, the method further includes: Obtaining the maximum allowable output current of the inverter; The preset curve is constructed according to the maximum allowable output current and the grid voltage.

9. The inverter power control device according to claim 6, characterized in that: The grid voltage includes: a grid line voltage of a three-phase three-wire system of a three-phase grid, a grid line voltage or a phase voltage of a three-phase four-wire system of a three-phase grid, and a phase voltage of a single-phase grid.

10. The inverter power control device according to claim 6, characterized in that: The voltage threshold is less than or equal to the rated voltage of the inverter.

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