Inverter shock-free grid connection method based on virtual synchronous generator comprehensive control

Abstract

The invention discloses an inverter shock-free grid connection method based on comprehensive control of a virtual synchronous generator, which belongs to the technical field of inverter control and specifically comprises the following steps of: setting a monitoring period T and acquiring an active power value and an active power instruction value of a grid-connected inverter in real time; calculating a difference value between the active power value and the active power instruction value, taking the difference value as target data, obtaining target data corresponding to all time points, taking the time points as abscissas and the target data as ordinates, generating a point location map, and fitting the point location map to obtain a target curve; acquiring a starting point, an ending point, a peak point and a valley point in the target curve and taking the starting point, the ending point, the peak point and the valley point as feature points, calculating a slope k between two adjacent feature points, calculating a change coefficient K according to the slope, and if K is greater than or equal to a preset threshold value, correcting the control parameters; according to the invention, the control parameters are adjusted by monitoring the operation state of the inverter, and the phenomena of overreaction and oscillation caused by the fluctuation of the power grid are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of inverter control, and in particular to an inverter impact-free grid-connected method based on comprehensive control of a virtual synchronous generator. Background Art

[0002] With the increasing depletion of traditional energy, distributed photovoltaic power generation systems have become an important part of electric energy. In a grid-connected photovoltaic power generation system, a grid-connected inverter is used to convert the DC power of the photovoltaic array into AC power with the same frequency as the grid voltage. The rated capacity of the photovoltaic grid-connected inverter matches the nominal power of the photovoltaic module. In order to output the nominal power of the photovoltaic module to the load, the given value of the reactive current is usually set to zero in the controller of the grid-connected inverter, that is, the output current and voltage are in phase, and the power factor is 1.

[0003] Traditional grid-connected inverters obtain frequency reference values ​​through droop control to achieve synchronization with the grid, but traditional droop control does not provide inertia for the grid, resulting in a large frequency change rate of the grid-connected inverter and deterioration of the frequency stability of the grid. In order to solve this problem, a virtual synchronous generator (VSG) control is proposed. By simulating the active power-frequency characteristics of traditional synchronous generators, the frequency change rate of the grid-connected inverter is indirectly adjusted to support the frequency stability of the power system. However, VSG control has a fixed moment of inertia and cannot adapt well to the dynamic changes of the grid load. When the load changes rapidly, the fixed moment of inertia may cause power oscillation and frequency fluctuation in the system. Summary of the invention

[0004] The purpose of the present invention is to provide an inverter impact-free grid connection method based on virtual synchronous generator integrated control to solve the following technical problems: Traditional grid-connected inverters obtain frequency reference values ​​through droop control to achieve synchronization with the grid, but traditional droop control does not provide inertia for the grid, resulting in a large frequency change rate of the grid-connected inverter and deterioration of the frequency stability of the grid. In order to solve this problem, a virtual synchronous generator (VSG) control is proposed. By simulating the active power-frequency characteristics of traditional synchronous generators, the frequency change rate of the grid-connected inverter is indirectly adjusted to support the frequency stability of the power system. However, VSG control has a fixed moment of inertia and cannot adapt well to the dynamic changes of the grid load. When the load changes rapidly, the fixed moment of inertia may cause power oscillation and frequency fluctuation in the system.

[0005] The purpose of the present invention can be achieved through the following technical solutions: The method for connecting an inverter to the grid without impact based on the integrated control of a virtual synchronous generator comprises the following steps: S1, controlling the grid-connected inverter to access the grid according to the control parameters of the preset virtual synchronous generator control strategy, setting a monitoring period T, and obtaining the active power value and active power command value of the grid-connected inverter in real time during the monitoring period; wherein the control parameters are the moment of inertia parameter and the damping coefficient; S2, selecting any time point within the monitoring period T, calculating the difference between the active power value of the grid-connected inverter and the active power command value at the time point and taking it as the target data w, obtaining the target data corresponding to all time points, taking the time point as the abscissa and the target data as the ordinate, generating a point map, fitting the point map to obtain a target curve F(t), where t is any time point; S3, obtain the starting point, end point, peak point and valley point in the target curve F(t) and use them as feature points, calculate the slope k between two adjacent feature points, and use the calculation formula Among them, h i is the time difference between the i-th feature point and the i+1-th feature point, n is the total number of feature points, k i The slope k between the i-th characteristic point and the i+1-th characteristic point is used to calculate the variation coefficient K. If K is greater than or equal to the preset threshold, the control parameters of the virtual synchronous generator control strategy are modified; if K is less than the preset threshold, the control parameters of the virtual synchronous generator control strategy are maintained.

[0006] As a further solution of the present invention: S1 also includes obtaining the amplitude, frequency and phase information of the grid voltage through a three-phase software phase-locked loop; applying the obtained phase information of the grid voltage to the dq transformation of the inverter output voltage, and then performing PI adjustment on its q-axis component and the zero reference, and obtaining the synchronous angular frequency from the output of the PI regulator; superimposing the synchronous angular frequency with the angular frequency generated by the droop control as the reference angular frequency of the inverter output voltage, and then synthesizing the inverter output reference voltage under the joint action of the droop control and the grid-connected pre-synchronization control, and controlling the inverter to access the grid with the reference voltage.

[0007] As a further solution of the present invention: in S3, the specific process of modifying the control parameters of the virtual synchronous generator control strategy is: According to the calculation formula Calculate the mean value VagW of the target data within the monitoring period. It means that the absolute values ​​of the target data within the monitoring period are summed. If the mean value VagW is greater than or equal to the preset mean value threshold, the moment of inertia parameter J0 of the current preset virtual synchronous generator control strategy is corrected to J0+N, where N is the preset recovery step length. If VagW is less than the preset mean value threshold, the moment of inertia parameter J0 of the current preset virtual synchronous generator control strategy is maintained. According to the calculation formula The average slope VagK is calculated. If the absolute value of the average slope VagK is greater than or equal to the preset slope threshold, the damping coefficient D0 of the current preset virtual synchronous generator control strategy is corrected to D0+M, where M is the preset limit step size. If the absolute value of the average slope VagK is less than the preset slope threshold, the damping coefficient D0 of the current preset virtual synchronous generator control strategy is maintained.

[0008] As a further solution of the present invention: S3 also includes if J0+N is greater than or equal to MAXJ, then the moment of inertia parameter J0 of the current preset virtual synchronous generator control strategy is corrected to MAXJ; if D0+M is greater than or equal to MAXD, then the damping coefficient of the current preset virtual synchronous generator control strategy is corrected to MAXD, wherein MAXJ is the preset maximum moment of inertia parameter value, and MAXD is the preset maximum damping coefficient value.

[0009] As a further solution of the present invention: S3 also includes correcting the next monitoring period H according to the variation coefficient.

[0010] As a further solution of the present invention: the specific process of correction is: ; Among them, T' is the revised monitoring period, K 标 is the preset change coefficient threshold, and β is the preset correction coefficient.

[0011] As a further solution of the present invention: S3 also includes: obtaining a characteristic point TZ1 corresponding to the starting point, and obtaining a characteristic point TZ2 adjacent to the characteristic point TZ1. If the slope between the characteristic point TZ1 and the characteristic point TZ2 is equal to 0, the monitoring period ends in advance and the moment of inertia parameter of the current virtual synchronous generator control strategy is corrected to the moment of inertia parameter J0; the damping coefficient of the current virtual synchronous generator control strategy is corrected to the damping coefficient D0.

[0012] As a further solution of the present invention: when the monitoring period ends early, the observation time that ends early is obtained and marked as t, and T=t is set, and S2 and S3 are repeated.

[0013] Beneficial effects of the present invention: In the present invention, the active power value and command value of the grid-connected inverter are obtained in real time, and the target data is calculated according to the changes in the monitoring period. It can be understood that by calculating the target data, the deviation and performance of the grid-connected inverter in actual operation can be judged. For example, if the target data is large (i.e., the active power value is far away from the active power command value), it means that the grid load fluctuates, and the control parameters (such as the moment of inertia and the damping coefficient) may need to be adjusted. However, considering that the actual grid is volatile, after detecting that the grid load has changed, the control parameters will not be directly corrected, but the monitoring period T is set, and the target data under the current control parameters is obtained during the monitoring period T. It can be understood that although the change in the grid load may cause the deviation between the active power value and the command value of the grid-connected inverter, due to the volatility of the grid itself, this deviation does not necessarily require the adjustment of the control parameters immediately. The change coefficient of the target data is calculated. It can be understood that the larger the change coefficient, the more drastic the actual load change of the grid, so it is necessary to adjust the control parameters to adapt to the dynamic change of the load. The smaller the change coefficient, the more stable the actual load change of the grid, so the original control parameters can be maintained to adapt to the dynamic change of the load. It is known that the target data is the difference between the active power value and the active power command value. The larger the target data is, the larger the power angle adjustment per unit time will be when the original control parameters remain unchanged. Therefore, overshoot may occur when the control parameters are kept fixed. Therefore, the mean of the target data within the monitoring period is calculated. The larger the mean, the larger the adjustment amount. Therefore, the moment of inertia parameter J0 of the current virtual synchronous generator control strategy is corrected to J0+N. The response speed is achieved by gradually increasing the moment of inertia parameter while reducing the actual adjustment amount. At the same time, the average slope is calculated. It can be understood that the larger the average slope is, the larger the oscillation of the system is, which may cause overshoot or oscillation in the system. The slope can be reduced by increasing the damping coefficient, making the system response slower. The present invention can monitor the operating status of the grid-connected inverter in real time, promptly identify the severity of the grid load change and adjust the control parameters, while ensuring the stability of the system, reducing overreaction and oscillation caused by grid volatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described below in conjunction with the accompanying drawings.

[0015] Figure 1 It is a flow chart of the inverter impact-free grid-connected method based on virtual synchronous generator comprehensive control of the present invention. DETAILED DESCRIPTION

[0016] 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 only 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.

[0017] See also Figure 1 As shown, the present invention is an inverter impact-free grid-connected method based on virtual synchronous generator integrated control, comprising the following steps: S1, controlling the grid-connected inverter to access the grid according to the control parameters of the preset virtual synchronous generator control strategy, setting a monitoring period T, and obtaining the active power value and active power command value of the grid-connected inverter in real time during the monitoring period; wherein the control parameters are the moment of inertia parameter and the damping coefficient; S2, selecting any time point within the monitoring period T, calculating the difference between the active power value of the grid-connected inverter and the active power command value at the time point and taking it as the target data w, obtaining the target data corresponding to all time points, taking the time point as the abscissa and the target data as the ordinate, generating a point map, fitting the point map to obtain a target curve F(t), where t is any time point; S3, obtain the starting point, end point, peak point and valley point in the target curve F(t) and use them as feature points, calculate the slope k between two adjacent feature points, and use the calculation formula Among them, h i is the time difference between the i-th feature point and the i+1-th feature point, n is the total number of feature points, k i The slope k between the i-th characteristic point and the i+1-th characteristic point is used to calculate the variation coefficient K. If K is greater than or equal to the preset threshold, the control parameters of the virtual synchronous generator control strategy are modified; if K is less than the preset threshold, the control parameters of the virtual synchronous generator control strategy are maintained.

[0018] In the present invention, the active power value and command value of the grid-connected inverter are obtained in real time, and the target data is calculated according to the changes in the monitoring period. It can be understood that by calculating the target data, the deviation and performance of the grid-connected inverter in actual operation can be judged. For example, if the target data is large (that is, the active power value is far away from the active power command value), it may indicate that the inverter fails to work according to the predetermined control strategy, and the control parameters (such as the moment of inertia and the damping coefficient) need to be adjusted. However, considering that the actual power grid is volatile, after detecting that the load of the power grid has changed, the control parameters will not be directly corrected, but the monitoring period T is set, and the target data under the current control parameters is obtained during the monitoring period T. It can be understood that although the change in the load of the power grid may cause the deviation between the active power value and the command value of the grid-connected inverter, due to the volatility of the power grid itself, this deviation does not necessarily require the adjustment of the control parameters immediately. The change coefficient of the target data is calculated. It can be understood that the larger the change coefficient, the more drastic the actual load change of the power grid, so it is necessary to adjust the control parameters to adapt to the dynamic change of the load. The larger the change coefficient, the more stable the actual load change of the power grid, so the original control parameters are maintained. The number can adapt to the dynamic change of load. It is known that the target data is the difference between the active power value and the active power command value. The larger the target data is, the larger the adjustment amount per unit time will be when the original control parameters remain unchanged. Therefore, overshoot will occur when the control parameters are kept fixed. Therefore, the mean value VagW of the target data in the monitoring period is calculated. The larger the VagW is, the larger the adjustment amount is, and overshoot may occur. Therefore, the moment of inertia parameter J0 of the current virtual synchronous generator control strategy is corrected to J0+N. At the same time, the average slope VagK is calculated. The larger the average slope is, the greater the oscillation of the system is, which may cause overshoot or oscillation in the system. The slope can be reduced by increasing the damping coefficient, so that the system response becomes slower. The present invention can monitor the operating status of the grid-connected inverter in real time, timely identify the severity of the grid load change and adjust the control parameters, while ensuring the stability of the system, reducing overreaction and oscillation caused by grid volatility.

[0019] It is worth noting that considering the volatility of the actual power grid, after detecting a sudden change in the power grid load, the present invention does not directly modify the control parameters, but sets a monitoring period T, and observes the target data under the current control parameters within the monitoring period T. It can be understood that although the change in the power grid load may cause a deviation between the active power value of the grid-connected inverter and the command value, due to the volatility of the power grid itself, this deviation does not necessarily require immediate adjustment of the control parameters. By calculating the coefficient of change of the target data within the monitoring period, it can be understood that the larger the coefficient of change, the more drastic the actual load change of the power grid, so it is necessary to adjust the control parameters to adapt to the dynamic changes in the load, and the smaller the coefficient of change, the more stable the actual overall load change of the power grid, so maintaining the original control parameters can adapt to the dynamic changes in the load; at the same time, in the present invention, the monitoring period T changes dynamically with the fluctuation of the power grid, and can adaptively respond to real-time changes in the power grid load. Usually, grid load fluctuations will fluctuate over time. By correcting the observation period, the time dimension of monitoring can be adjusted more flexibly to avoid information lag or over-concentration caused by fixed periods. When the variation coefficient K is large, it means that the grid load fluctuation is large, so the next observation period H can be shortened to provide more frequent adjustments; when the variation coefficient K is small, it means that the grid load is relatively stable, and the observation period can be extended to reduce the consumption of computing resources and unnecessary frequent adjustments. By correcting the observation period according to the variation coefficient, the impact of grid fluctuations on the inverter can be captured more accurately. For unstable grid conditions, shortening the observation period can help the system respond to changes more promptly and adjust control parameters. In periods when the grid load is relatively stable, extending the period can reduce unnecessary parameter adjustments and avoid the system burden caused by excessive adjustments.

[0020] In a preferred embodiment of the present invention, S1 also includes obtaining the amplitude, frequency and phase information of the grid voltage through a three-phase software phase-locked loop; applying the obtained phase information of the grid voltage to the dq transformation of the inverter output voltage, and then performing PI adjustment on its q-axis component and the zero reference, and obtaining the synchronous angular frequency from the output of the PI regulator; superimposing the synchronous angular frequency with the angular frequency generated by the droop control as the reference angular frequency of the inverter output voltage, and then synthesizing the inverter output reference voltage under the joint action of the droop control and the grid-connected pre-synchronization control, and controlling the inverter to access the grid with the reference voltage.

[0021] In another preferred embodiment of the present invention, in said S3, the specific process of modifying the control parameters of the virtual synchronous generator control strategy is: According to the calculation formula Calculate the mean value VagW of the target data within the monitoring period. It means that the absolute values ​​of the target data within the monitoring period are summed. If the mean value VagW is greater than or equal to the preset mean value threshold, the moment of inertia parameter J0 of the current preset virtual synchronous generator control strategy is corrected to J0+N, where N is the preset recovery step length. If VagW is less than the preset mean value threshold, the moment of inertia parameter J0 of the current preset virtual synchronous generator control strategy is maintained. According to the calculation formula The average slope VagK is calculated. If the absolute value of the average slope VagK is greater than or equal to the preset slope threshold, the damping coefficient D0 of the current preset virtual synchronous generator control strategy is corrected to D0+M, where M is the preset limit step size. If the absolute value of the average slope VagK is less than the preset slope threshold, the damping coefficient D0 of the current preset virtual synchronous generator control strategy is maintained.

[0022] In another preferred embodiment of the present invention, S3 also includes if J0+N is greater than or equal to MAXJ, then the moment of inertia parameter J0 of the current preset virtual synchronous generator control strategy is corrected to MAXJ; if D0+M is greater than or equal to MAXD, then the damping coefficient of the current preset virtual synchronous generator control strategy is corrected to MAXD, wherein MAXJ is the preset maximum moment of inertia parameter value, and MAXD is the preset maximum damping coefficient value.

[0023] In another preferred embodiment of the present invention, the S3 further includes correcting the next monitoring period H according to the variation coefficient.

[0024] By adjusting the next observation period H according to the variation coefficient K, the real-time changing grid load can be adaptively responded to. Usually, grid load fluctuations will fluctuate over time. By correcting the observation period, the time dimension of monitoring can be adjusted more flexibly to avoid information lag or excessive concentration caused by fixed periods. When the variation coefficient K is large, it means that the grid load fluctuates greatly, so the next observation period H can be shortened to provide more frequent adjustments; when the variation coefficient K is small, it means that the grid load is relatively stable, and the observation period can be extended to reduce the consumption of computing resources and unnecessary frequent adjustments. By correcting the observation period according to the variation coefficient, the impact of grid fluctuations on the inverter can be captured more accurately. For unstable grid conditions, shortening the observation period can help the system respond to changes more promptly and adjust control parameters. In periods when the grid load is relatively stable, extending the period can reduce unnecessary parameter adjustments and avoid the system burden caused by excessive adjustments.

[0025] In another preferred embodiment of the present invention, the specific process of correction is: ; Among them, T' is the revised monitoring period, K 标is the preset change coefficient threshold, and β is the preset correction coefficient.

[0026] In another preferred embodiment of the present invention, S3 also includes: obtaining a characteristic point TZ1 corresponding to the starting point, and obtaining a characteristic point TZ2 adjacent to the characteristic point TZ1; if the slope between the characteristic point TZ1 and the characteristic point TZ2 is equal to 0, the monitoring period ends in advance and the moment of inertia parameter of the current virtual synchronous generator control strategy is corrected to the moment of inertia parameter J0; the damping coefficient of the current virtual synchronous generator control strategy is corrected to the damping coefficient D0.

[0027] The slope between the characteristic point TZ1 and the characteristic point TZ2 is equal to 0, which means that the inverter and the grid are in a stable state at the current moment, and the preset J0 and D0 are parameters optimized according to system design and experiments, which can effectively ensure the stable operation of the system. Therefore, when the slope is zero, restoring to these preset control parameters can ensure the optimal performance of the inverter in a steady state.

[0028] In another preferred embodiment of the present invention, when the monitoring period ends early, the observation duration that ends early is obtained and marked as t, and T=t is set, and S2 and S3 are repeated.

[0029] When it is detected that the inverter and the grid are in a stable state, ending the monitoring cycle in advance can avoid unnecessary waste of computing resources. Since the system state changes dynamically, setting T=t can ensure that the starting point of each monitoring and control cycle is based on the actual performance of the current system, rather than a predetermined fixed time period. More flexible and accurate control adjustments can be made according to real-time changes. For example, if it is detected that the inverter and the grid enter a steady state ahead of time, redefining the monitoring cycle based on the actual observation time can make the control parameters (such as moment of inertia J0, damping coefficient D) more suitable for the current working state, thereby improving the stability and efficiency of the system, ensuring that the early end of the monitoring cycle will not cause unnecessary delays or reaction lags, and can adjust the control strategy in time to cope with rapidly changing power fluctuations.

[0030] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. An inverter impact-free grid-connected method based on comprehensive control of virtual synchronous generators, characterized in that: The following steps are involved: S1, controlling the grid-connected inverter to access the grid according to the control parameters of the preset virtual synchronous generator control strategy, setting a monitoring period T, and obtaining the active power value and active power command value of the grid-connected inverter in real time during the monitoring period; wherein the control parameters are the moment of inertia parameter and the damping coefficient; S2, selecting any time point within the monitoring period T, calculating the difference between the active power value of the grid-connected inverter and the active power command value at the time point and taking it as the target data w, obtaining the target data corresponding to all time points, taking the time point as the abscissa and the target data as the ordinate, generating a point map, fitting the point map to obtain a target curve F(t), where t is any time point; S3, obtain the starting point, end point, peak point and valley point in the target curve F(t) and use them as feature points, calculate the slope k between two adjacent feature points, and use the calculation formula , where h i is the time difference between the i-th feature point and the i+1-th feature point, n is the total number of feature points, k i The slope k between the i-th characteristic point and the i+1-th characteristic point is used to calculate the variation coefficient K. If K is greater than or equal to the preset threshold, the control parameters of the virtual synchronous generator control strategy are modified; if K is less than the preset threshold, the control parameters of the virtual synchronous generator control strategy are maintained.

2. The method for inverter non-impact grid connection based on virtual synchronous generator integrated control according to claim 1, characterized in that: The S1 also includes obtaining the amplitude, frequency and phase information of the grid voltage through a three-phase software phase-locked loop; applying the obtained phase information of the grid voltage to the dq transformation of the inverter output voltage, and then performing PI adjustment on its q-axis component and the zero reference, and obtaining the synchronous angular frequency from the output of the PI regulator; superimposing the synchronous angular frequency with the angular frequency generated by the droop control as the reference angular frequency of the inverter output voltage, and then synthesizing the inverter output reference voltage under the joint action of the droop control and the grid-connected pre-synchronization control, and controlling the inverter to access the grid with the reference voltage.

3. The method for inverter non-impact grid connection based on virtual synchronous generator integrated control according to claim 1, characterized in that: In S3, the specific process of modifying the control parameters of the virtual synchronous generator control strategy is as follows: According to the calculation formula Calculate the mean value VagW of the target data within the monitoring period. It means that the absolute values ​​of the target data within the monitoring period are summed. If the mean value VagW is greater than or equal to the preset mean value threshold, the moment of inertia parameter J0 of the current preset virtual synchronous generator control strategy is corrected to J0+N, where N is the preset recovery step length. If VagW is less than the preset mean value threshold, the moment of inertia parameter J0 of the current preset virtual synchronous generator control strategy is maintained. According to the calculation formula The average slope VagK is calculated. If the absolute value of the average slope VagK is greater than or equal to the preset slope threshold, the damping coefficient D0 of the current preset virtual synchronous generator control strategy is corrected to D0+M, where M is the preset limit step size. If the absolute value of the average slope VagK is less than the preset slope threshold, the damping coefficient D0 of the current preset virtual synchronous generator control strategy is maintained.

4. The method for inverter non-impact grid connection based on virtual synchronous generator integrated control according to claim 3 is characterized in that: The S3 also includes if J0+N is greater than or equal to MAXJ, then the moment of inertia parameter J0 of the current preset virtual synchronous generator control strategy is corrected to MAXJ; if D0+M is greater than or equal to MAXD, then the damping coefficient of the current preset virtual synchronous generator control strategy is corrected to MAXD, wherein the MAXJ is the preset maximum moment of inertia parameter value, and the MAXD is the preset maximum damping coefficient value.

5. The method for inverter non-impact grid connection based on virtual synchronous generator integrated control according to claim 3, characterized in that: The S3 also includes correcting the next monitoring period H according to the variation coefficient.

6. The method for inverter non-impact grid connection based on virtual synchronous generator integrated control according to claim 5, characterized in that: The specific process of correction is: ； Among them, T' is the revised monitoring period, K 标 is the preset change coefficient threshold, and β is the preset correction coefficient.

7. The method for inverter non-impact grid connection based on virtual synchronous generator integrated control according to claim 3, characterized in that: The S3 also includes: obtaining a characteristic point TZ1 corresponding to the starting point, and obtaining a characteristic point TZ2 adjacent to the characteristic point TZ1. If the slope between the characteristic point TZ1 and the characteristic point TZ2 is equal to 0, the monitoring period ends in advance and the moment of inertia parameter of the current virtual synchronous generator control strategy is corrected to the moment of inertia parameter J0, and the damping coefficient of the current virtual synchronous generator control strategy is corrected to the damping coefficient D0.

8. The method for inverter non-impact grid connection based on virtual synchronous generator integrated control according to claim 7, characterized in that: It also includes that when the monitoring cycle ends early, the observation time that ends early is obtained and marked as t, and T=t is set, and S2 and S3 are repeated.

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