Energy storage converter control method and system under low voltage ride through

Abstract

The invention relates to the technical field of photovoltaic energy storage converters, and particularly discloses an energy storage converter control method and system under low voltage ride through, and the method comprises the steps: obtaining a grid-connected point voltage value of a photovoltaic power station, determining a voltage state value according to the grid-connected point voltage value of the photovoltaic power station, and judging a low voltage ride through state of a power grid according to the voltage state value; if it is judged that the power grid is in the low-voltage ride-through state, an energy storage converter control strategy is determined according to energy storage converter operation parameters in the power grid low-voltage ride-through process; obtaining performance data of the energy storage converter, and determining an initial control strategy adjustment parameter according to the performance data of the energy storage converter; and correcting the initial control strategy adjustment parameter according to the voltage state value to obtain a corrected control strategy adjustment parameter, and adjusting the energy storage converter control strategy according to the corrected control strategy adjustment parameter to obtain a final control strategy. The control effect of low-voltage ride-through can be effectively improved, and the reliability and stability of power grid operation are ensured.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic energy storage inverters, and more specifically, to a control method and system for an energy storage inverter under low voltage ride through. Background Art

[0002] Low Voltage Ride Through (LVRT) means that when the grid voltage temporarily drops below a certain percentage of the rated voltage due to a fault or fluctuation, the photovoltaic power generation system can remain grid-connected for a certain period of time without disconnecting due to the voltage drop.

[0003] In the prior art, since the reasons for the low voltage sag of the grid are diverse and prone to change, it is difficult to obtain an optimal control strategy for the photovoltaic energy storage inverter, resulting in poor control effect of the photovoltaic energy storage inverter. Summary of the Invention

[0004] The present invention provides a control method and system for an energy storage inverter under low voltage ride through to solve the problem of poor control effect of the photovoltaic energy storage inverter in the prior art, including:

[0005] Obtain the grid connection point voltage value of the photovoltaic power station, determine the voltage state value according to the grid connection point voltage value of the photovoltaic power station, and judge the low voltage ride through state of the grid according to the voltage state value;

[0006] If it is judged that the grid is in the low voltage ride through state, determine the control strategy of the energy storage inverter according to the operating parameters of the energy storage inverter during the low voltage ride through process of the grid;

[0007] Obtain the performance data of the energy storage inverter, and determine the initial control strategy adjustment parameter according to the performance data of the energy storage inverter;

[0008] Correct the initial control strategy adjustment parameter according to the voltage state value to obtain the corrected control strategy adjustment parameter, and adjust the control strategy of the energy storage inverter according to the corrected control strategy adjustment parameter to obtain the final control strategy.

[0009] Further, the determining the voltage state value according to the grid connection point voltage value of the photovoltaic power station and judging the low voltage ride through state of the grid according to the voltage state value includes:

[0010] Determine the grid voltage change situation according to the grid connection point voltage value of the photovoltaic power station, and draw a grid voltage change curve according to the grid voltage change situation;

[0011] Obtain the preset minimum voltage threshold, screen out the voltage values less than the minimum voltage threshold in the grid voltage change curve, and calculate the voltage drop amplitude;

[0012] Statistically calculate the duration during which the voltage value in the power grid voltage change curve is less than the minimum voltage threshold, and determine the low-voltage duration based on the duration during which the voltage value is less than the minimum voltage threshold;

[0013] Determine the voltage status value based on the voltage drop amplitude and the low-voltage duration. When the voltage status value is greater than the first preset threshold, it is determined that the power grid is not in the low-voltage ride-through state;

[0014] When the voltage status value is less than or equal to the first preset threshold, it is determined that the power grid is in the low-voltage ride-through state.

[0015] Further, the determining the voltage status value based on the voltage drop amplitude and the low-voltage duration includes:

[0016] Calculate the voltage status value according to the voltage status value calculation formula. The voltage status value calculation formula is specifically:

[0017]

[0018] where S is the voltage status value, n is the preset voltage statistical period, D i is the voltage drop amplitude in the i-th time period, and T i is the corresponding low-voltage duration in the i-th time period, and exp is the natural exponential function.

[0019] Further, the determining the energy storage converter control strategy based on the operating parameters of the energy storage converter during the low-voltage ride-through process of the power grid includes:

[0020] Determine the internal potential amplitude and phase angle based on the operating parameters of the energy storage converter during the low-voltage ride-through process of the power grid, obtain a three-phase sine wave, and determine the energy storage converter control strategy according to the three-phase sine wave.

[0021] Further, the determining the energy storage converter control strategy according to the three-phase sine wave includes:

[0022] Obtain the historical three-phase sine wave of the energy storage converter and the corresponding control strategy, and establish a training sample set according to the historical three-phase sine wave of the energy storage converter and the corresponding control strategy;

[0023] Establish an initial control strategy evaluation model according to the training sample set and train the initial control strategy evaluation model to obtain a trained control strategy evaluation model;

[0024] Obtain the three-phase sine wave of the current energy storage converter, and input the three-phase sine wave of the current energy storage converter into the trained control strategy evaluation model to obtain the energy storage converter control strategy.

[0025] Further, the determining the initial control strategy adjustment parameters according to the performance data of the energy storage converter includes:

[0026] Determine the response time, temperature stability data, and equipment quality parameters of the energy storage converter during low-voltage ride-through according to the performance data of the energy storage converter, and normalize the response time, temperature stability data, and equipment quality parameters;

[0027] Convert the normalized response time, temperature stability data, and equipment quality parameters into a first line segment, a second line segment, and a third line segment respectively according to a preset ratio;

[0028] Connect the midpoints of the first line segment and the second line segment, draw a rhombus according to the first line segment and the second line segment after the midpoint connection, set the length of the third line segment as the height of the rhombus, and establish a triangular pyramid;

[0029] Calculate the area value of the triangular pyramid, determine the performance parameters of the energy storage converter according to the area value of the triangular pyramid, and determine the initial control strategy adjustment parameters according to the performance parameters of the energy storage converter.

[0030] Further, the temperature stability data of the energy storage converter during low-voltage ride-through is specifically:

[0031] Obtain the temperature change situation of the energy storage converter during low-voltage ride-through, and draw a temperature change curve according to the temperature change situation of the energy storage converter during low-voltage ride-through;

[0032] Obtain a preset sliding time window, divide the temperature change curve according to the preset sliding time window, and obtain a number of segmented temperature change curves;

[0033] Statistically calculate the average temperature of each segmented temperature change curve, and draw an average value change curve according to the average temperature of all segmented temperature change curves;

[0034] Statistically calculate the absolute value of the slope of adjacent average temperatures in the average value change curve, calculate the average value of all absolute values of the slopes, and determine the temperature stability data according to the average value of the slopes of the average value change curve.

[0035] Further, the correction of the initial control strategy adjustment parameters according to the voltage state value includes:

[0036] Obtain a preset allowable voltage state value, and calculate the difference between the current voltage state value and the preset allowable voltage state value;

[0037] Judge whether the difference between the voltage state value and the preset allowable voltage state value is greater than a second preset threshold. If the difference between the voltage state value and the preset allowable voltage state value is greater than the second preset threshold, set a first correction parameter to correct the initial control strategy adjustment parameters;

[0038] If the difference between the voltage state value and the preset allowable voltage state value is less than or equal to the second preset threshold, then determine whether the difference between the voltage state value and the preset allowable voltage state value is greater than the third preset threshold;

[0039] If the difference between the voltage state value and the preset allowable voltage state value is greater than the third preset threshold, then set the second correction parameter to correct the initial control strategy adjustment parameter;

[0040] If the difference between the voltage state value and the preset allowable voltage state value is less than or equal to the third preset threshold, then set the third correction parameter to correct the initial control strategy adjustment parameter.

[0041] Further, adjusting the energy storage converter control strategy according to the corrected control strategy adjustment parameter to obtain the final control strategy includes:

[0042] Obtain the historical low-voltage ride-through event data of the photovoltaic power station, and determine the correlation coefficient between each control target value and the final control effect in the historical control strategy of the energy storage converter according to the historical low-voltage ride-through event data of the photovoltaic power station;

[0043] Assign weight values to each control target value according to the correlation coefficient between each control target value and the final control effect, and multiply the weight value of each control target value by the corrected control strategy adjustment parameter to obtain the adjustment parameter of the control target value;

[0044] Multiply the adjustment parameter of the control target value by the corresponding control target value, and determine the final control strategy according to the adjusted control target value.

[0045] To achieve the above object, the present invention also provides a control system for an energy storage converter under low-voltage ride-through, including:

[0046] The first module is used to obtain the grid connection point voltage value of the photovoltaic power station, determine the voltage state value according to the grid connection point voltage value of the photovoltaic power station, and judge the low-voltage ride-through state of the power grid according to the voltage state value;

[0047] The second module is used to, if it is judged that the power grid is in the low-voltage ride-through state, determine the energy storage converter control strategy according to the operation parameters of the energy storage converter during the low-voltage ride-through process of the power grid;

[0048] The third module is used to obtain the performance data of the energy storage converter and determine the initial control strategy adjustment parameter according to the performance data of the energy storage converter;

[0049] The fourth module is used to correct the initial control strategy adjustment parameter according to the voltage state value to obtain the corrected control strategy adjustment parameter, and adjust the energy storage converter control strategy according to the corrected control strategy adjustment parameter to obtain the final control strategy.

[0050] The beneficial effects of the present invention are as follows:

[0051] By applying the above technical solution, the present invention obtains the grid connection point voltage value of the photovoltaic power station, determines the voltage status value according to the grid connection point voltage value of the photovoltaic power station, and judges the low voltage ride-through status of the power grid according to the voltage status value; if it is judged that the power grid is in the low voltage ride-through state, the energy storage converter control strategy is determined according to the operation parameters of the energy storage converter during the low voltage ride-through process of the power grid; the performance data of the energy storage converter is obtained, and the initial control strategy adjustment parameters are determined according to the performance data of the energy storage converter; the initial control strategy adjustment parameters are corrected according to the voltage status value to obtain the corrected control strategy adjustment parameters, and the energy storage converter control strategy is adjusted according to the corrected control strategy adjustment parameters to obtain the final control strategy. It can effectively improve the control effect of low voltage ride-through and ensure the reliability and stability of power grid operation. Brief Description of the Drawings

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative efforts.

[0053] Figure 1 Fig. shows the overall flowchart of a control method for an energy storage converter under low voltage ride-through proposed by an embodiment of the present invention;

[0054] Figure 2 Fig. shows the structural schematic diagram of a control system for an energy storage converter under low voltage ride-through proposed by an embodiment of the present invention. Detailed Embodiments

[0055] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0056] The embodiment of the present application provides a control method for an energy storage converter under low voltage ride-through, as Figure 1 shown, including:

[0057] S101, obtaining the grid connection point voltage value of the photovoltaic power station, determining the voltage status value according to the grid connection point voltage value of the photovoltaic power station, and judging the low voltage ride-through status of the power grid according to the voltage status value;

[0058] In some embodiments of the present application, determining the voltage state value according to the grid connection point voltage value of the photovoltaic power station and judging the low voltage ride-through state of the power grid includes: determining the power grid voltage change situation according to the grid connection point voltage value of the photovoltaic power station, and drawing a power grid voltage change curve according to the power grid voltage change situation; obtaining a preset minimum voltage threshold, screening out the voltage values in the power grid voltage change curve that are less than the minimum voltage threshold, and calculating the voltage dip amplitude; counting the duration during which the voltage value in the power grid voltage change curve is less than the minimum voltage threshold, and determining the low voltage duration according to the duration during which the voltage value is less than the minimum voltage threshold; determining the voltage state value according to the voltage dip amplitude and the low voltage duration, and when the voltage state value is greater than the first preset threshold, judging that the power grid is not in the low voltage ride-through state; when the voltage state value is less than or equal to the first preset threshold, judging that the power grid is in the low voltage ride-through state.

[0059] In this embodiment, the voltage state value is calculated through the voltage change situation of the power grid, and then the power grid voltage state is judged through the voltage state value, which can more accurately judge the voltage state of the power grid and facilitate subsequent energy storage converter control according to the voltage state.

[0060] In some embodiments of the present application, determining the voltage state value according to the voltage dip amplitude and the low voltage duration includes: calculating the voltage state value according to the voltage state value calculation formula, and the voltage state value calculation formula is specifically

[0061]

[0062] where S is the voltage state value, n is the preset voltage statistical period, D i is the voltage dip amplitude in the i-th time period, and T i is the corresponding low voltage duration in the i-th time period, and exp is the natural exponential function.

[0063] In this embodiment, the preset voltage statistical period is divided into several parts according to time periods, and the voltage state value is obtained through the voltage dip amplitude and the low voltage duration of each time period.

[0064] S102, if it is judged that the power grid is in the low voltage ride-through state, then determine the energy storage converter control strategy according to the operation parameters of the energy storage converter during the low voltage ride-through process of the power grid;

[0065] In some embodiments of the present application, determining the energy storage converter control strategy according to the operation parameters of the energy storage converter during the low voltage ride-through process of the power grid includes: determining the internal potential amplitude and phase angle according to the operation parameters of the energy storage converter during the low voltage ride-through process of the power grid, obtaining a three-phase sine wave, and determining the energy storage converter control strategy according to the three-phase sine wave.

[0066] In this embodiment, when the power grid is in a low-voltage state, the specific voltage sag type is obtained from the three-phase sine wave of the energy storage converter, and then the corresponding control strategy is obtained.

[0067] In some embodiments of the present application, the determining the control strategy of the energy storage converter according to the three-phase sine wave includes: obtaining the historical three-phase sine wave of the energy storage converter and the corresponding control strategy, and establishing a training sample set according to the historical three-phase sine wave of the energy storage converter and the corresponding control strategy; establishing an initial control strategy evaluation model according to the training sample set and training the initial control strategy evaluation model to obtain a trained control strategy evaluation model; obtaining the three-phase sine wave of the current energy storage converter, and inputting the three-phase sine wave of the current energy storage converter into the trained control strategy evaluation model to obtain the control strategy of the energy storage converter.

[0068] In this embodiment, a training sample set is established by collecting the historical three-phase sine wave of the energy storage converter and the corresponding control strategy during the historical voltage crossing process, and the current control strategy of the energy storage converter is obtained through the control strategy evaluation model trained by the training sample set.

[0069] S103, obtaining the performance data of the energy storage converter, and determining the initial control strategy adjustment parameter according to the performance data of the energy storage converter;

[0070] In some embodiments of the present application, the determining the initial control strategy adjustment parameter according to the performance data of the energy storage converter includes: determining the response time, temperature stability data and equipment quality parameters of the energy storage converter during the low-voltage ride-through process according to the performance data of the energy storage converter, and normalizing the response time, temperature stability data and equipment quality parameters; converting the normalized response time, temperature stability data and equipment quality parameters into a first line segment, a second line segment and a third line segment according to a preset ratio; connecting the midpoints of the first line segment and the second line segment, drawing a rhombus according to the first line segment and the second line segment after the midpoint connection, setting the length of the third line segment as the height of the rhombus, and establishing a triangular pyramid; calculating the area value of the triangular pyramid, determining the performance parameter of the energy storage converter according to the area value of the triangular pyramid, and determining the initial control strategy adjustment parameter according to the performance parameter of the energy storage converter.

[0071] In some embodiments of the present application, the temperature stability data of the energy storage converter during low-voltage ride-through is specifically as follows: Obtain the temperature change of the energy storage converter during low-voltage ride-through, and draw a temperature change curve according to the temperature change of the energy storage converter during low-voltage ride-through; obtain a preset sliding time window, and divide the temperature change curve according to the preset sliding time window to obtain several segmented temperature change curves; count the average temperature of each segmented temperature change curve, and draw an average value change curve according to the average temperature of all segmented temperature change curves; count the absolute value of the slope of adjacent average temperatures in the average value change curve, calculate the average value of all absolute values of the slopes, and determine the temperature stability data according to the average value of the slopes of the average value change curve.

[0072] In this embodiment, a triangular pyramid is established by combining the response time, temperature stability data, and equipment quality parameters of the energy storage converter during low-voltage ride-through. The performance parameters of the energy storage converter are obtained through the area value of the triangular pyramid. The equipment quality parameter of the energy storage converter is specifically the power conversion efficiency of the energy storage converter. The initial control strategy adjustment parameter is determined by establishing a mapping table of performance parameter - initial control strategy adjustment parameter. The range of the initial control strategy adjustment parameter is between 0 and 2. The smaller the performance parameter, the higher the corresponding initial control strategy adjustment parameter. The control strategy adjustment parameter can adjust the control target value of the energy storage converter in the low-voltage ride-through control strategy to achieve precise control of the energy storage converter.

[0073] S104. Modify the initial control strategy adjustment parameter according to the voltage state value to obtain the modified control strategy adjustment parameter, and adjust the energy storage converter control strategy according to the modified control strategy adjustment parameter to obtain the final control strategy.

[0074] In some embodiments of the present application, the modification of the initial control strategy adjustment parameter according to the voltage state value includes: obtaining a preset allowable voltage state value, and calculating the difference between the current voltage state value and the preset allowable voltage state value; determining whether the difference between the voltage state value and the preset allowable voltage state value is greater than a second preset threshold. If the difference between the voltage state value and the preset allowable voltage state value is greater than the second preset threshold, set a first correction parameter to modify the initial control strategy adjustment parameter; if the difference between the voltage state value and the preset allowable voltage state value is less than or equal to the second preset threshold, determine whether the difference between the voltage state value and the preset allowable voltage state value is greater than a third preset threshold; if the difference between the voltage state value and the preset allowable voltage state value is greater than the third preset threshold, set a second correction parameter to modify the initial control strategy adjustment parameter; if the difference between the voltage state value and the preset allowable voltage state value is less than or equal to the third preset threshold, set a third correction parameter to modify the initial control strategy adjustment parameter.

[0075] In this embodiment, the corresponding correction parameter is obtained based on the difference between the current voltage state value and the preset allowable voltage state value to correct the initial control strategy adjustment parameter. The greater the difference, the greater the corresponding correction parameter value. The final control strategy adjustment parameter is obtained by multiplying the correction parameter value by the initial control strategy adjustment parameter.

[0076] In some embodiments of the present application, adjusting the energy storage converter control strategy according to the corrected control strategy adjustment parameter to obtain the final control strategy includes: obtaining the historical low-voltage ride-through event data of the photovoltaic power station, and determining the correlation coefficient between each control target value and the final control effect in the historical control strategy of the energy storage converter according to the historical low-voltage ride-through event data of the photovoltaic power station; allocating weight values to each control target value according to the correlation coefficient between each control target value and the final control effect, multiplying the weight value of each control target value by the corrected control strategy adjustment parameter to obtain the adjustment parameter of the control target value; multiplying the adjustment parameter of the control target value by the corresponding control target value, and determining the final control strategy according to the adjusted control target value.

[0077] In this embodiment, weight values are allocated to each control target value according to the correlation coefficient between each control target value and the final control effect in the historical control strategy of the energy storage converter. The greater the correlation coefficient, the higher the corresponding weight value. After obtaining the adjustment parameter of the control target value, the control target value is adjusted, and then the final control strategy is obtained.

[0078] Based on the same technical concept, as Figure 2 shown, the present invention also provides a control system for an energy storage converter under low-voltage ride-through, including:

[0079] A first module, configured to obtain the grid connection point voltage value of the photovoltaic power station, determine the voltage state value according to the grid connection point voltage value of the photovoltaic power station, and judge the low-voltage ride-through state of the power grid according to the voltage state value; a second module, configured to, if it is judged that the power grid is in the low-voltage ride-through state, determine the energy storage converter control strategy according to the operation parameters of the energy storage converter during the low-voltage ride-through process of the power grid; a third module, configured to obtain the performance data of the energy storage converter and determine the initial control strategy adjustment parameter according to the performance data of the energy storage converter; a fourth module, configured to correct the initial control strategy adjustment parameter according to the voltage state value to obtain the corrected control strategy adjustment parameter, and adjust the energy storage converter control strategy according to the corrected control strategy adjustment parameter to obtain the final control strategy.

[0080] By applying the above technical solutions, the present invention obtains the grid connection point voltage value of the photovoltaic power station, determines the voltage state value according to the grid connection point voltage value of the photovoltaic power station, and judges the low voltage ride-through state of the power grid according to the voltage state value; if it is judged that the power grid is in the low voltage ride-through state, the energy storage converter control strategy is determined according to the operation parameters of the energy storage converter during the low voltage ride-through process of the power grid; the performance data of the energy storage converter is obtained, and the initial control strategy adjustment parameter is determined according to the performance data of the energy storage converter; the initial control strategy adjustment parameter is corrected according to the voltage state value to obtain the corrected control strategy adjustment parameter, and the energy storage converter control strategy is adjusted according to the corrected control strategy adjustment parameter to obtain the final control strategy. The present invention can effectively improve the control effect of low voltage ride-through and ensure the reliability and stability of the power grid operation.

[0081] Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by hardware or by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present invention can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various implementation scenarios of the present invention.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present application.

Claims

1. A method for controlling an energy storage converter under low voltage ride-through, characterized in that: The method comprises: Obtain the grid-connected point voltage value of the photovoltaic power station, determine the voltage state value according to the grid-connected point voltage value of the photovoltaic power station, and judge the low voltage ride-through state of the power grid according to the voltage state value; If it is determined that the power grid is in a low voltage ride-through state, the energy storage converter control strategy is determined according to the operating parameters of the energy storage converter during the low voltage ride-through process of the power grid; Acquire performance data of the energy storage converter, and determine initial control strategy adjustment parameters according to the performance data of the energy storage converter; The initial control strategy adjustment parameters are corrected according to the voltage state value to obtain the corrected control strategy adjustment parameters, and the energy storage converter control strategy is adjusted according to the corrected control strategy adjustment parameters to obtain the final control strategy.

2. The method for controlling an energy storage converter under low voltage ride-through according to claim 1, characterized in that: Determining the voltage state value according to the grid connection point voltage value of the photovoltaic power station, and judging the low voltage ride-through state of the power grid according to the voltage state value, includes: Determine the grid voltage change according to the grid connection point voltage value of the photovoltaic power station, and draw the grid voltage change curve according to the grid voltage change; Obtain a preset minimum voltage threshold, filter out voltage values ​​less than the minimum voltage threshold in the grid voltage change curve, and calculate the voltage drop amplitude; Counting the duration of the voltage value in the grid voltage change curve being less than the minimum voltage threshold, and determining the low voltage duration according to the duration of the voltage value being less than the minimum voltage threshold; Determine a voltage state value according to the voltage drop amplitude and the low voltage duration, and when the voltage state value is greater than a first preset threshold, determine that the power grid is not in a low voltage ride-through state; When the voltage state value is less than or equal to the first preset threshold, it is determined that the power grid is in a low voltage ride through state.

3. The method for controlling an energy storage converter under low voltage ride-through according to claim 2, characterized in that: Determining the voltage state value according to the voltage drop amplitude and the low voltage duration includes: The voltage state value is calculated according to the voltage state value calculation formula, and the voltage state value calculation formula is specifically: Among them, S is the voltage state value, n is the preset voltage statistical period, D i is the voltage drop amplitude in the i-th time period, T i is the low pressure duration corresponding to the i-th time period, and exp is the natural exponential function.

4. The method for controlling an energy storage converter under low voltage ride-through according to claim 3, characterized in that: The step of determining the energy storage converter control strategy according to the energy storage converter operating parameters during the low voltage ride-through process of the power grid includes: The internal potential amplitude and phase angle are determined according to the operating parameters of the energy storage converter during the low voltage ride-through process of the power grid to obtain a three-phase sine wave, and the energy storage converter control strategy is determined according to the three-phase sine wave.

5. The method for controlling an energy storage converter under low voltage ride-through according to claim 4, characterized in that: Determining the energy storage converter control strategy according to the three-phase sine wave includes: Obtain historical three-phase sine waves and corresponding control strategies of the energy storage converter, and establish a training sample set according to the historical three-phase sine waves and corresponding control strategies of the energy storage converter; Establishing an initial control strategy evaluation model according to the training sample set and training the initial control strategy evaluation model to obtain a trained control strategy evaluation model; The three-phase sine wave of the current energy storage converter is obtained, and the three-phase sine wave of the current energy storage converter is input into the trained control strategy evaluation model to obtain the energy storage converter control strategy.

6. The method for controlling an energy storage converter under low voltage ride-through according to claim 5, characterized in that: The step of determining the initial control strategy adjustment parameters according to the performance data of the energy storage converter includes: Determine the response time, temperature stability data and equipment quality parameters of the energy storage converter during the low voltage ride-through process according to the performance data of the energy storage converter, and normalize the response time, temperature stability data and equipment quality parameters; Convert the normalized response time, temperature stability data and equipment quality parameters into the first line segment, the second line segment and the third line segment respectively according to a preset ratio; Connect the midpoints of the first line segment and the second line segment, draw a rhombus based on the first line segment and the second line segment whose midpoints are connected, set the length of the third line segment as the height of the rhombus, and establish a triangular pyramid; The area value of the triangular pyramid is calculated, the performance parameters of the energy storage converter are determined according to the area value of the triangular pyramid, and the initial control strategy adjustment parameters are determined according to the performance parameters of the energy storage converter.

7. The method for controlling an energy storage converter under low voltage ride-through according to claim 6, characterized in that: The temperature stability data of the energy storage converter during the low voltage ride-through process are specifically as follows: Obtaining the temperature change of the energy storage converter during the low voltage ride-through process, and drawing a temperature change curve according to the temperature change of the energy storage converter during the low voltage ride-through process; Obtain a preset sliding time window, and segment the temperature change curve according to the preset sliding time window to obtain a plurality of segmented temperature change curves; Count the temperature average of each segment temperature change curve, and draw the average value change curve according to the temperature average of all segment temperature change curves; The absolute values ​​of the slopes of adjacent temperature average values ​​in the mean value change curve are counted, the average value of all the absolute values ​​of the slopes is calculated, and the temperature stability data is determined according to the average value of the slope of the mean value change curve.

8. The method for controlling an energy storage converter under low voltage ride-through according to claim 7, characterized in that: The step of modifying the initial control strategy adjustment parameters according to the voltage state value includes: Obtaining a preset allowable voltage state value, and calculating a difference between a current voltage state value and the preset allowable voltage state value; Determine whether the difference between the voltage state value and the preset allowable voltage state value is greater than a second preset threshold value, and if the difference between the voltage state value and the preset allowable voltage state value is greater than the second preset threshold value, set a first correction parameter to correct the initial control strategy adjustment parameter; If the difference between the voltage state value and the preset allowable voltage state value is less than or equal to the second preset threshold, determining whether the difference between the voltage state value and the preset allowable voltage state value is greater than a third preset threshold; If the difference between the voltage state value and the preset allowable voltage state value is greater than a third preset threshold, then setting a second correction parameter to correct the initial control strategy adjustment parameter; If the difference between the voltage state value and the preset allowable voltage state value is less than or equal to the third preset threshold, the third correction parameter is set to correct the initial control strategy adjustment parameter.

9. The method for controlling an energy storage converter under low voltage ride-through according to claim 8, characterized in that: The energy storage converter control strategy is adjusted according to the modified control strategy adjustment parameters to obtain a final control strategy, including: Obtain historical low voltage ride-through event data of the photovoltaic power station, and determine the correlation coefficient between each control target value and the final control effect in the historical control strategy of the energy storage converter according to the historical low voltage ride-through event data of the photovoltaic power station; According to the correlation coefficient between each control target value and the final control effect, a weight value is assigned to each control target value, and the weight value of each control target value is multiplied by the modified control strategy adjustment parameter to obtain the adjustment parameter of the control target value; The adjustment parameter of the control target value is multiplied by the corresponding control target value, and the final control strategy is determined according to the adjusted control target value.

10. A low voltage ride-through energy storage converter control system, characterized in that: include: The first module is used to obtain the grid connection point voltage value of the photovoltaic power station, determine the voltage state value according to the grid connection point voltage value of the photovoltaic power station, and judge the low voltage ride-through state of the power grid according to the voltage state value; The second module is used to determine the energy storage converter control strategy according to the energy storage converter operation parameters during the low voltage ride-through process of the power grid if it is determined that the power grid is in a low voltage ride-through state; The third module is used to obtain the performance data of the energy storage converter and determine the initial control strategy adjustment parameters according to the performance data of the energy storage converter; The fourth module is used to correct the initial control strategy adjustment parameters according to the voltage state value to obtain the corrected control strategy adjustment parameters, and adjust the energy storage converter control strategy according to the corrected control strategy adjustment parameters to obtain the final control strategy.

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