Self-adaptive control technology for rotational inertia and damping coefficient of optical storage VSG system

Abstract

A self-adaptive control technology for rotational inertia and damping coefficient of an optical storage VSG system comprises a grid-connected system overall structure which is provided with an energy storage device, takes photovoltaic as a source end and is controlled by a grid-connected inverter virtual synchronous machine, and the grid-connected system overall structure is formed by electrically connecting a photovoltaic array, the energy storage device, an inverter, a DC / DC (Direct Current / Direct Current), a converter and a filter; the energy storage device is additionally arranged at a direct current bus of the system, the energy storage device and the photovoltaic array form a common direct current bus structure, the inverter is controlled by a virtual synchronous machine, inertial response and frequency adjustment are provided for the optical storage power generation system, and the power shortage between the photovoltaic array and the photovoltaic inverter is made up by adding the energy storage device; and the frequency deviation and the frequency change rate are introduced into VSG parameters, and the inertia and damping parameters of the VSG system are adaptively adjusted, so that the frequency stability of the micro-grid during power sudden change is improved, and the direct-current measurement energy storage power balance is met.

Description

Technical Field

[0001] The invention belongs to the technical field of microgrid inverter control, and relates to a technology for adaptively controlling the moment of inertia and damping coefficient of a photovoltaic storage VSG system. Background Art

[0002] Renewable energy such as wind power and photovoltaics has been rapidly developed in various countries due to its advantages of cleanliness and high efficiency. However, with the increasing proportion of new energy power generation and the withdrawal of corresponding synchronous generators, the system inertia level and primary frequency regulation resources are gradually reduced, posing severe challenges to the stability of the power system. Conventional photovoltaic grid-connected inverters have the disadvantages of low inertia and weak damping. Their large-scale access to the power grid will lead to insufficient inertia and damping of the overall power grid, making it difficult to provide sufficient voltage support and frequency regulation capabilities for the power grid, which will have an adverse effect on the stability of the system. In current research at home and abroad, VSG technology has been widely used. This method simulates the SG rotor characteristics of synchronous generators to make the grid-connected inverter have inertia and damping. It improves the ability of new energy grid-connected inverters to suppress their own output frequency and power fluctuations and meet the technical specifications of new energy grid-connected operation.

[0003] When the microgrid is subjected to a large power disturbance, the fixed parameter virtual synchronous generator (VSG) control can provide inertia and damping for the system, but it cannot guarantee the frequency regulation performance and has poor control flexibility. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an adaptive control technology for the moment of inertia and damping coefficient of a photovoltaic energy storage VSG system, introduce the frequency deviation and frequency change rate into the VSG parameters, and adaptively adjust the inertia and damping parameters of the VSG system to improve the frequency stability of the microgrid when the power changes suddenly, and meet the DC energy storage power balance.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: an adaptive control technology of the moment of inertia and damping coefficient of the photovoltaic storage VSG system, which includes an overall structure of a grid-connected system controlled by a virtual synchronous machine of a grid-connected inverter with photovoltaic as the source end and an energy storage device, and is composed of a photovoltaic array, an energy storage device, an inverter, a DC / DC and a converter and a filter electrically connected; the energy storage device is installed at the DC bus of the system to form a common DC bus structure with the photovoltaic array, and the inverter is controlled by a virtual synchronous machine to provide inertial response and frequency adjustment for the photovoltaic storage power generation system, and the power shortage between the photovoltaic array and the photovoltaic inverter is compensated by adding an energy storage device.

[0006] The inverter adopts a three-phase inverter, the AC power grid is a three-phase AC power grid, and the filter circuit adopts an LCL filter circuit; the three-phase grid-connected inverter part is a voltage-type PWM rectifier grid-connected control.

[0007] The frequency deviation and frequency change rate are introduced into the VSG parameters to adaptively adjust the inertia and damping parameters of the VSG system; when the frequency deviation and frequency change rate change, the VSG parameters change accordingly, thereby improving the frequency stability of the microgrid when power mutation occurs.

[0008] The energy storage device is connected to the DC bus of the inverter through a bidirectional DC / DC converter, and the circuit topology adopts a buck / boost circuit; a dual closed-loop control structure with a DC bus voltage outer loop and an inductor current inner loop is adopted; first, the DC bus voltage reference value Udcref is subtracted from the actual value Udc, and the difference is sent to the voltage loop PI regulator to obtain the reference value iref of the output current; then, iref is subtracted from the collected energy storage output current ib, and the difference is sent to the current loop PI regulator to obtain a PWM modulation signal; finally, a pulse signal is generated through PWM control to control the switch tube of the buck / boost circuit to realize the charging and discharging operation of the energy storage device to stabilize the DC bus voltage at the rated value.

[0009] The grid-connected inverter virtual synchronous machine control with photovoltaic as the source end, when the power output of VSG is greater than the power output of photovoltaic, the energy storage unit releases power to make up for the shortfall between the two. At this time, the power of the energy storage unit is greater than 0, the energy storage current is positive, and the DC / DC circuit works in boost mode; when the power output of photovoltaic is greater than the power output of VSG, the energy storage unit absorbs power to make up for the shortfall between the two. The power of the energy storage unit is less than 0, the energy storage current is negative, and the DC / DC circuit works in buck mode; therefore, the output power P of the photovoltaic virtual synchronous machine is equal to the sum of the photovoltaic output power Ppv and the energy storage unit output power Pb, that is ;;The control of VSG active loop imitates the inertia and primary frequency modulation characteristics of SG, and the control of reactive loop imitates the primary voltage regulation characteristics of SG; The SG rotor motion equation is as follows:

[0010] Where J is the moment of inertia of the synchronous generator; is the grid synchronization angular velocity; , They are the mechanical torque and electromagnetic torque of the synchronous generator respectively, and D is the damping coefficient.

[0011] The grid-connected inverter refers to the basic principle of the SG speed regulator, simulates the SG primary frequency and voltage regulation characteristics, and adopts the active frequency and reactive voltage droop characteristics. The equation is as follows:

[0012]

[0013] In the formula , They are the rated active power and rated reactive power of VSG respectively; , They are the active frequency droop coefficient and the reactive voltage droop coefficient respectively; the control block diagram of the active loop and reactive loop of the VSG is obtained based on the active frequency droop characteristics, reactive voltage droop coefficient and rotor motion equation of the synchronous generator.

[0014] The VSG active loop and reactive loop imitate the transient characteristics of SG; the output of the VSG active loop is used as the frequency and phase of the inverter modulation wave, and the output of the reactive loop is used as the amplitude of the inverter modulation wave; the expressions of the inverter three-phase modulation waves ema, emb, and emc are as follows:

[0015] It is known from the power angle curve and frequency oscillation curve of SG that when the given active power of SG increases from P1 to P2, the system operating point will obtain the original stable operating point b through a series of attenuated oscillation processes; for the convenience of analysis, the typical oscillation process is divided into four areas with constant inertia moment and damping coefficient: ①t1-t2, ②t2-t3, ③t3-t4, ④t4-t5; in interval ①, the virtual rotor angular velocity of SG is greater than the grid angular velocity and gradually increases, and the change of angular velocity dω / dt first increases and then gradually decreases; therefore, in interval ①, the moment of inertia J and the damping coefficient D are increased to prevent the angular velocity change and frequency deviation from being too large, so as to suppress the increase of the rotor angular velocity; in interval ②, the rate of change of the virtual rotor angular velocity is less than zero, entering the deceleration stage, and the angular frequency starts to decrease from the maximum value, but ω>ω0, that is, the virtual rotor angular velocity is still greater than the grid angular velocity; and the angular velocity is accelerated to the rated value with a smaller moment of inertia; in intervals ③ and ④, the selection of the moment of inertia and damping coefficient is the same as that of intervals ① and ②.

[0016] When the dispatch instruction changes, select an oscillation cycle in the simulated power frequency curve in the fixed parameter control mode, and divide the cycle into four intervals; obtain the parameter changes in these four intervals and conduct a detailed analysis; according to the analysis results, adjust the parameters of each interval, including corresponding control parameter adjustments to the moment of inertia and damping coefficient.

[0017] The VSG moment of inertia J and the damping coefficient D of the photovoltaic storage are coordinated with the adaptive control strategy, where the formula of the VSG moment of inertia J and the damping coefficient D of the photovoltaic storage is:

[0018]

[0019] Among them, J0 and D0 are the moment of inertia and damping coefficient of VSG when it is running stably, respectively. When VSG is running stably, the moment of inertia J0 and damping coefficient D0 are set as the second-order system according to the “optimal method” to obtain faster response speed and smaller overshoot; K j and K d are the moment of inertia and damping coefficient adjustment coefficients respectively; M j and M d are the change thresholds respectively.

[0020] The main beneficial effects of the present invention are: The energy storage unit is responsible for smoothing the difference between the photovoltaic output power and the inverter power command.

[0021] Renewable energy generation that meets the requirements of the power system can be connected to the grid and provide auxiliary services to maintain the stable operation of the power system.

[0022] Improve the power balance and frequency regulation flexibility of the photovoltaic storage VSG system.

[0023] The frequency deviation and frequency change rate are introduced into the VSG parameters, and the inertia and damping parameters of the VSG system are adaptively adjusted to improve the frequency stability of the microgrid when the power changes suddenly and meet the power balance of DC energy storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0025] Figure 1 This is the overall topology diagram of the optical storage VSG system of the present invention.

[0026] Figure 2 This is a topological diagram of the bidirectional DC / DC converter of the present invention.

[0027] Figure 3 This is a discharge mode diagram of the energy storage system circuit of the present invention.

[0028] Figure 4 This is a charging mode diagram of the energy storage system circuit of the present invention.

[0029] Figure 5 This is the VSG active frequency loop control diagram of the present invention.

[0030] Figure 6 This is the active power diagram output by the VSG of the present invention.

[0031] Figure 7 This is the VSG output frequency diagram of the present invention.

[0032] Figure 8 This is the output voltage diagram of the VSG DC side of the present invention.

[0033] Fig. 9 This is the VSG adaptive inertia and damping change diagram of the present invention. DETAILED DESCRIPTION

[0034] like Figure 1 to Figure 9 In the invention, a technology for adaptive control of rotational inertia and damping coefficient of photovoltaic storage VSG system is disclosed, which includes an overall structure of a grid-connected system controlled by a virtual synchronous machine of a grid-connected inverter with photovoltaic as the source end and an energy storage device, and is composed of a photovoltaic array, an energy storage device, an inverter, a DC / DC and a converter and a filter electrically connected; the energy storage device is installed at the DC bus of the system to form a common DC bus structure with the photovoltaic array, and the inverter is controlled by a virtual synchronous machine to provide inertial response and frequency adjustment for the photovoltaic storage power generation system, and the power shortage between the photovoltaic array and the photovoltaic inverter is compensated by adding an energy storage device.

[0035] In a preferred solution, the inverter is a three-phase inverter, the AC power grid is a three-phase AC power grid, the filter circuit is an LCL filter circuit; and the three-phase grid-connected inverter part is a voltage-type PWM rectifier grid-connected control.

[0036] In the preferred solution, the frequency deviation and frequency change rate are introduced into the VSG parameters, and the inertia and damping parameters of the VSG system are adaptively adjusted; when the frequency deviation and frequency change rate change, the VSG parameters change accordingly, thereby improving the frequency stability of the microgrid when power changes suddenly.

[0037] In the preferred scheme, the energy storage device is connected to the DC bus of the inverter through a bidirectional DC / DC converter, and the circuit topology adopts a buck / boost circuit; a dual closed-loop control structure of a DC bus voltage outer loop and an inductor current inner loop is adopted; first, the DC bus voltage reference value Udcref is subtracted from the actual value Udc, and the difference is sent to the voltage loop PI regulator to obtain the reference value iref of the output current; then, iref is subtracted from the collected energy storage output current ib, and the difference is sent to the current loop PI regulator to obtain a PWM modulation signal; finally, a pulse signal is generated through PWM control to control the switch tube of the buck / boost circuit to realize the charging and discharging operation of the energy storage device to stabilize the DC bus voltage at the rated value.

[0038] In the preferred solution, the grid-connected inverter virtual synchronous machine is controlled with photovoltaic as the source end. When the power output of VSG is greater than the power output of photovoltaic, the energy storage unit releases power to make up for the shortfall between the two. At this time, the power of the energy storage unit is greater than 0, the energy storage current is positive, and the DC / DC circuit works in boost mode; when the power output of photovoltaic is greater than the power output of VSG, the energy storage unit absorbs power to make up for the shortfall between the two. The power of the energy storage unit is less than 0, the energy storage current is negative, and the DC / DC circuit works in buck mode; therefore, the output power P of the photovoltaic virtual synchronous machine is equal to the sum of the photovoltaic output power Ppv and the energy storage unit output power Pb, that is, ;;The control of VSG active loop imitates the inertia and primary frequency modulation characteristics of SG, and the control of reactive loop imitates the primary voltage regulation characteristics of SG; The SG rotor motion equation is as follows:

[0039] Where J is the moment of inertia of the synchronous generator; is the grid synchronization angular velocity; , They are the mechanical torque and electromagnetic torque of the synchronous generator respectively, and D is the damping coefficient.

[0040] In the preferred solution, the grid-connected inverter refers to the basic principle of the SG speed regulator, simulates the SG primary frequency and voltage regulation characteristics, and adopts the active frequency and reactive voltage droop characteristics, and its equation is as follows:

[0041]

[0042] In the formula , They are the rated active power and rated reactive power of VSG respectively; , They are the active frequency droop coefficient and the reactive voltage droop coefficient respectively; the control block diagram of the active loop and reactive loop of the VSG is obtained based on the active frequency droop characteristics, reactive voltage droop coefficient and rotor motion equation of the synchronous generator.

[0043] In the preferred solution, the VSG active loop and reactive loop imitate the transient characteristics of the SG; the output of the VSG active loop is used as the frequency and phase of the inverter modulation wave, and the output of the reactive loop is used as the amplitude of the inverter modulation wave; the expressions of the inverter three-phase modulation waves ema, emb, and emc are as follows:

[0044] It is known from the power angle curve and frequency oscillation curve of SG that when the given active power of SG increases from P1 to P2, the system operating point will obtain the original stable operating point b through a series of attenuated oscillation processes; for the convenience of analysis, the typical oscillation process is divided into four areas with constant inertia moment and damping coefficient: ①t1-t2, ②t2-t3, ③t3-t4, ④t4-t5; in interval ①, the virtual rotor angular velocity of SG is greater than the grid angular velocity and gradually increases, and the change of angular velocity dω / dt first increases and then gradually decreases; therefore, in interval ①, the moment of inertia J and the damping coefficient D are increased to prevent the angular velocity change and frequency deviation from being too large, so as to suppress the increase of the rotor angular velocity; in interval ②, the rate of change of the virtual rotor angular velocity is less than zero, entering the deceleration stage, and the angular frequency starts to decrease from the maximum value, but ω>ω0, that is, the virtual rotor angular velocity is still greater than the grid angular velocity; and the angular velocity is accelerated to the rated value with a smaller moment of inertia; in intervals ③ and ④, the selection of the moment of inertia and damping coefficient is the same as that of intervals ① and ②.

[0045] In the preferred scheme, when the scheduling instruction changes, an oscillation cycle in the power frequency curve simulated in the fixed parameter control mode is selected, and the cycle is divided into four intervals; the parameter changes in these four intervals are obtained and analyzed in detail; according to the analysis results, the parameters of each interval are adjusted, including corresponding control parameter adjustments to the moment of inertia and damping coefficient.

[0046] In the preferred solution, the VSG moment of inertia J and the damping coefficient D of the light storage are coordinated with an adaptive control strategy, wherein the formula of the VSG moment of inertia J and the damping coefficient D of the light storage is:

[0047]

[0048] Among them, J0 and D0 are the moment of inertia and damping coefficient of VSG when it is running stably, respectively. When VSG is running stably, the moment of inertia J0 and damping coefficient D0 are set as the second-order system according to the “optimal method” to obtain faster response speed and smaller overshoot; K j and K d are the moment of inertia and damping coefficient adjustment coefficients respectively; M j and M d are the change thresholds respectively.

[0049] Embodiment 1, Select an oscillation cycle in the simulated power-frequency curve under the fixed parameter control mode, and divide the oscillation cycle into four intervals, ①t1-t2, ②t2-t3, ③t3-t4, ④t4-t5, and analyze the parameter changes in each interval respectively. According to the analysis results, the moment of inertia and damping coefficient are adjusted according to the strategy of practical control parameter adjustment. Among them, the changes of various parameters from t1 to t5 are shown in the following table:

[0050]

[0051]

[0052] J0 and D0 are the moment of inertia and damping coefficient of VSG during stable operation, respectively.

[0053] The adaptive control technology of the VSG moment of inertia J and the damping coefficient D is coordinated to introduce the frequency deviation and frequency change rate into the VSG parameters, and adaptively adjust the inertia and damping parameters of the VSG system to improve the frequency stability of the microgrid when the power changes suddenly.

[0054] In order to verify the feasibility of the proposed control strategy, a single-machine VSG simulation model is established in Matlab / Simulink for verification. The inverter DC bus voltage Udc=700V shows the simulation results of VSG in grid-connected mode, and the simulation time is set to 1.5s. The damping J0 is set to 0.2, and the inertia D is set to 12. At the beginning, the active power given by VSG is 10kW, which increases to 15kW at 0.5s and falls back to 12kW at 1.0s. When the input power increases sharply, the output frequency deviation of VSG with fixed inertia and damping is large.

[0055] The adaptive inertia damping control technology proposed by the above technical solution can effectively reduce frequency deviation. Compared with the traditional fixed parameter VSG control, the inertia damping coordinated adaptive VSG control has better frequency fluctuation suppression performance, which can not only reduce the rate of change of frequency fluctuation, but also reduce the frequency offset, and ultimately reduce the frequency overshoot, improve the frequency stability performance, and also show that VSG has strong flexibility in control. In addition, the adaptive inertia damping control technology proposed by the above technical solution can keep the DC side bus voltage at 700V even when the load fluctuates, so that the energy of the entire photovoltaic storage VSG system remains balanced.

[0056] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. An adaptive control technology of moment of inertia and damping coefficient of VSG system. Its characteristics are: It includes an overall grid-connected system structure controlled by a virtual synchronous machine with a grid-connected inverter with photovoltaic as the source end and an energy storage device, which is composed of a photovoltaic array, an energy storage device, an inverter, a DC / DC and a converter and a filter electrically connected; the energy storage device is installed on the DC bus of the system to form a common DC bus structure with the photovoltaic array, and the inverter is controlled by a virtual synchronous machine to provide inertial response and frequency adjustment for the photovoltaic power generation system, and the power shortage between the photovoltaic array and the photovoltaic inverter is compensated by adding an energy storage device.

2. According to claim 1, the adaptive control technology of the moment of inertia and damping coefficient of the photovoltaic storage VSG system, Its characteristics are: The inverter adopts a three-phase inverter, the AC power grid is a three-phase AC power grid, and the filter circuit adopts an LCL filter circuit; the three-phase grid-connected inverter part is a voltage-type PWM rectifier grid-connected control.

3. According to any one of claims 1 to 2, the adaptive control technology of the moment of inertia and damping coefficient of the photovoltaic storage VSG system, Its characteristics are: The frequency deviation and frequency change rate are introduced into the VSG parameters to adaptively adjust the inertia and damping parameters of the VSG system; when the frequency deviation and frequency change rate change, the VSG parameters change accordingly, thereby improving the frequency stability of the microgrid when power mutation occurs.

4. According to claim 3, the adaptive control technology of the moment of inertia and damping coefficient of the photovoltaic storage VSG system, Its characteristics are: The energy storage device is connected to the DC bus of the inverter through a bidirectional DC / DC converter, and the circuit topology adopts a buck / boost circuit; a dual closed-loop control structure with a DC bus voltage outer loop and an inductor current inner loop is adopted; first, the DC bus voltage reference value Udcref is subtracted from the actual value Udc, and the difference is sent to the voltage loop PI regulator to obtain the reference value iref of the output current; then, iref is subtracted from the collected energy storage output current ib, and the difference is sent to the current loop PI regulator to obtain a PWM modulation signal; finally, a pulse signal is generated through PWM control to control the switch tube of the buck / boost circuit to realize the charging and discharging operation of the energy storage device to stabilize the DC bus voltage at the rated value.

5. According to claim 3, the adaptive control technology of the moment of inertia and damping coefficient of the photovoltaic storage VSG system, Its characteristics are: The grid-connected inverter virtual synchronous machine control with photovoltaic as the source end, when the power output of VSG is greater than the power output of photovoltaic, the energy storage unit releases power to make up for the shortfall between the two. At this time, the power of the energy storage unit is greater than 0, the energy storage current is positive, and the DC / DC circuit works in boost mode; when the power output of photovoltaic is greater than the power output of VSG, the energy storage unit absorbs power to make up for the shortfall between the two. The power of the energy storage unit is less than 0, the energy storage current is negative, and the DC / DC circuit works in buck mode; therefore, the output power P of the photovoltaic virtual synchronous machine is equal to the sum of the photovoltaic output power Ppv and the energy storage unit output power Pb, that is ; The control of the VSG active loop imitates the inertia and primary frequency modulation characteristics of the SG, and the control of the reactive loop imitates the primary voltage regulation characteristics of the SG; The SG rotor motion equation is as follows: Where J is the moment of inertia of the synchronous generator; is the grid synchronization angular velocity; , They are the mechanical torque and electromagnetic torque of the synchronous generator respectively, and D is the damping coefficient.

6. According to claim 5, the adaptive control technology of the moment of inertia and damping coefficient of the photovoltaic storage VSG system, Its characteristics are: grid-connected The inverter refers to the basic principle of SG speed regulator, simulates the primary frequency and voltage regulation characteristics of SG, and adopts the active frequency and reactive voltage droop characteristics. The equation is as follows: In the formula , They are the rated active power and rated reactive power of VSG respectively; , They are the active frequency droop coefficient and the reactive voltage droop coefficient respectively; the control block diagram of the active loop and reactive loop of the VSG is obtained based on the active frequency droop characteristics, reactive voltage droop coefficient and rotor motion equation of the synchronous generator.

7. The adaptive control technology of moment of inertia and damping coefficient of the photovoltaic storage VSG system according to claim 6, Its characteristics are: The VSG active loop and reactive loop imitate the transient characteristics of SG; the output of the VSG active loop is used as the frequency and phase of the inverter modulation wave, and the output of the reactive loop is used as the amplitude of the inverter modulation wave; the expressions of the inverter three-phase modulation waves ema, emb, and emc are as follows: It is known from the power angle curve and frequency oscillation curve of SG that when the given active power of SG increases from P1 to P2, the system operating point will obtain the original stable operating point b through a series of attenuated oscillation processes; for the convenience of analysis, the typical oscillation process is divided into four areas with constant inertia moment and damping coefficient: ①t1-t2, ②t2-t3, ③t3-t4, ④t4-t5; in interval ①, the virtual rotor angular velocity of SG is greater than the grid angular velocity and gradually increases, and the change of angular velocity dω / dt first increases and then gradually decreases; therefore, in interval ①, the moment of inertia J and the damping coefficient D are increased to prevent the angular velocity change and frequency deviation from being too large, so as to suppress the increase of the rotor angular velocity; in interval ②, the rate of change of the virtual rotor angular velocity is less than zero, entering the deceleration stage, and the angular frequency starts to decrease from the maximum value, but ω>ω0, that is, the virtual rotor angular velocity is still greater than the grid angular velocity; and the angular velocity is accelerated to the rated value with a smaller moment of inertia; in intervals ③ and ④, the selection of the moment of inertia and damping coefficient is the same as that of intervals ① and ②.

8. According to claim 7, the adaptive control technology of the moment of inertia and damping coefficient of the photovoltaic storage VSG system, Its characteristics are: When the dispatch instruction changes, select an oscillation cycle in the simulated power frequency curve in the fixed parameter control mode, and divide the cycle into four intervals; obtain the parameter changes in these four intervals and conduct a detailed analysis; according to the analysis results, adjust the parameters of each interval, including corresponding control parameter adjustments to the moment of inertia and damping coefficient.

9. The adaptive control technology of moment of inertia and damping coefficient of the photovoltaic storage VSG system according to claim 7, Its characteristics are: The VSG moment of inertia J and the damping coefficient D of the photovoltaic storage are coordinated with the adaptive control strategy, where the formula of the VSG moment of inertia J and the damping coefficient D of the photovoltaic storage is: Among them, J 0 and D 0 They are the moment of inertia and damping coefficient when VSG is running stably. When VSG is running stably, the moment of inertia J 0 and the damping coefficient D 0 Set the second-order system according to the "optimal method" to obtain faster response speed and smaller overshoot; K j and K d are the moment of inertia and damping coefficient adjustment coefficients respectively; M j and M d are the change thresholds respectively.

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