A synchronous grid-connection adaptive equalization control method, system, device and medium

Abstract

This invention relates to the field of power system grid connection control technology, specifically to a synchronous grid-connected adaptive equalization control method, system, device, and medium for achieving an adaptive equalization control mechanism for synchronous access between a virtual synchronous generator (VSG) and the power grid. The method acquires voltage signals from both the VSG and grid sides, calculates the frequency and voltage offsets on both sides of the grid connection switch, performs initial adjustment using a PI regulator, introduces an adaptive control loop, and dynamically adjusts the control factor based on real-time frequency errors, thereby improving system frequency stability and dynamic response. When the frequency, phase, and voltage amplitude differences on both sides of the grid connection interface meet the synchronous grid connection standards, the switch is closed, enabling the inverter to safely connect to the grid. This invention effectively improves grid connection stability and reliability and is applicable to various power system application scenarios.

Description

Technical Field

[0001] This invention relates to the field of power system grid connection control technology. Background Technology

[0002] With the increasing proportion of renewable energy sources being integrated into the grid, microgrids face the dual challenges of insufficient inertia and damping. Traditional synchronous generators can effectively buffer disturbances due to their mechanical inertia, while inverter systems lack corresponding inertia support. When frequency disturbances occur, the system's frequency regulation capability weakens, and its stability is easily affected. To enhance the dynamic response capability of microgrids under disturbances, it is necessary to simulate the dynamic characteristics of traditional synchronous machines in the inverter control. By constructing an equivalent rotor motion model, the system's frequency stability and disturbance rejection capability can be effectively improved.

[0003] Currently, microgrid inverters typically operate in both off-grid and grid-connected modes, with smooth switching between the two. However, during the switch from off-grid to grid-connected mode, the frequency and amplitude of the virtual synchronous generator (VSG) output voltage may deviate from the grid voltage. Direct connection to the grid could trigger transient inrush currents and threaten the safety of electrical equipment. Therefore, to ensure stable system operation, the VSG control method needs to be improved to synchronize its output voltage with the grid voltage before connection.

[0004] Currently, pre-synchronization methods mainly include phase-locked loop (PLL) based control schemes and virtual power control strategies that do not require PLLs. The former achieves synchronization through phase-locked loop technology, but it is highly dependent on the accuracy of the PLL; the latter constructs a virtual impedance and adjusts the voltage / current reference values ​​to make the output voltage tend to the grid waveform. However, in such methods, the coupling between phase and amplitude can still lead to synchronization errors.

[0005] To address the aforementioned issues, there is an urgent need to propose a synchronous grid-connected stability adaptive equalization control method that takes into account both frequency and voltage offset. Summary of the Invention

[0006] To overcome the problems of poor frequency stability of existing VSG off-grid operation, insufficient frequency and voltage synchronization accuracy in traditional grid-connected control, slow pre-synchronization, and easy generation of transient impacts during grid connection, this invention provides a synchronous grid-connected adaptive equalization control method, system, device, and medium.

[0007] The technical solution adopted by this invention to achieve the above objectives is: a synchronous grid-connected adaptive equalization control method, comprising:

[0008] Collect three-phase voltage signals from the VSG side and the grid side, and obtain the grid-side voltage in the stationary α-β coordinate system through Clark transformation. , Components and VSG side voltage , The active power difference between the two sides of the grid-connected switch is calculated and input into the frequency PI regulator to generate the pre-synchronization frequency regulation amount.

[0009] Collect real-time VSG side frequency and grid side frequency, calculate frequency offset and frequency recovery integral coefficient, and generate frequency adaptive compensation amount;

[0010] The real-time active power on the VSG side is collected, and the correction frequency and correction phase angle are calculated by combining the pre-synchronization frequency adjustment and frequency adaptive compensation.

[0011] Based on the voltage components on the grid side and the voltage components on the VSG side, the voltage difference between the two sides of the grid-connected switch is calculated, and the voltage difference is input into the voltage PI regulator to generate the pre-synchronization voltage regulation amount.

[0012] The real-time reactive power collected on the VSG side is combined with the pre-synchronization voltage regulation to calculate the correction voltage amplitude.

[0013] The frequency difference, voltage amplitude difference, and phase angle difference on both sides of the grid-connected switch are calculated using the correction frequency, correction phase angle, and correction voltage amplitude, and are monitored in real time. When all three meet the preset grid connection criteria, the grid-connected switch is closed.

[0014] Preferably, the active power difference on both sides of the grid-connected switch is calculated. for:

[0015] ;

[0016] in, , These are the grid-side voltages. , Quantity, , VSG side voltage , Quantity;

[0017] Transfer function of frequency PI regulator for:

[0018] ;

[0019] in, This refers to the gain parameter used for proportional adjustment in a frequency PI controller. This refers to the gain parameter used for integral regulation in a frequency PI controller. For the Laplace operator;

[0020] Pre-synchronization frequency adjustment The calculation formula is:

[0021] ;

[0022] in, For time variables, It is the integral variable.

[0023] Preferably, frequency offset The calculation formula is:

[0024] ;

[0025] in, For the real-time frequency on the power grid side, Real-time frequency on the VSG side;

[0026] Frequency recovery integral coefficient The calculation formula is:

[0027] ;

[0028] Frequency adaptive compensation amount The calculation formula is:

[0029] .

[0030] Preferably, the correction frequency The calculation formula is:

[0031] ;

[0032] in, For rotational inertia, The damping coefficient is... This is the active power reference value. For the real-time active power collected from the VSG side, The initial frequency on the VSG side;

[0033] Correction phase angle The calculation formula is:

[0034] .

[0035] Preferably, the voltage difference across the grid-connected switch The calculation formula is:

[0036] ;

[0037] Transfer function of voltage PI regulator for:

[0038] ;

[0039] in, This refers to the gain parameter used for proportional control in a voltage PI regulator. This refers to the gain parameter used for integral regulation in a voltage PI regulator;

[0040] Pre-synchronization voltage regulation The calculation formula is:

[0041] .

[0042] Preferably, the corrected voltage amplitude The calculation formula is:

[0043] ;

[0044] in, This is the voltage-controlled droop coefficient. This is the baseline value for reactive power. For the real-time reactive power collected on the VSG side, This is the initial voltage on the VSG side.

[0045] Preferably, the grid connection criterion is:

[0046] Frequency difference between the two sides of the grid-connected switch satisfy ,in ;

[0047] Voltage amplitude difference on both sides of the grid-connected switch satisfy ,in ;

[0048] Voltage phase angle difference on both sides of the grid-connected switch satisfy ,in ;

[0049] in, , , Do not set the preset frequency difference threshold, voltage amplitude difference threshold, and phase angle difference threshold. This is the rated voltage of the power grid.

[0050] A synchronous grid-connected adaptive equalization control system includes:

[0051] Signal acquisition module: used to acquire real-time three-phase voltage signals, real-time active power, real-time reactive power, VSG side frequency, and grid side three-phase voltage signals and grid side frequency;

[0052] Coordinate transformation module: Electrically connected to the signal acquisition module, with built-in Clark transformation algorithm, used to receive three-phase voltage signals, perform coordinate transformation and output voltage components in the stationary α-β coordinate system;

[0053] Control processing module: electrically connected to the signal acquisition module and coordinate transformation module, including frequency adaptive submodule, active power-frequency control submodule, voltage regulation submodule, and reactive power-voltage control submodule;

[0054] Frequency Adaptive Submodule: Receives the three-phase voltage signal output from the coordinate transformation module, calculates the active power difference, and generates a pre-synchronization frequency adjustment amount through the built-in frequency PI regulator; simultaneously, it receives the VSG side frequency and grid side frequency output from the signal acquisition module, and calculates the frequency offset and frequency adaptive compensation amount.

[0055] Active-frequency control submodule: Receives pre-synchronization frequency adjustment and frequency adaptive compensation, and outputs correction frequency and correction phase angle;

[0056] Voltage regulation submodule: Receives the voltage component output by the coordinate transformation module, calculates the voltage difference, and generates a pre-synchronization voltage regulation amount through the built-in voltage PI regulator;

[0057] Reactive power-voltage control submodule: Receives real-time reactive power and pre-synchronization voltage regulation from the VSG side, and outputs the corrected voltage amplitude;

[0058] Grid connection execution module: Electrically connected to the control processing module, it detects frequency difference, voltage amplitude difference and phase angle difference in real time. When the grid connection criteria are met, it controls the grid connection switch to close, completing the synchronous access of VSG and the power grid.

[0059] A synchronous grid-connected adaptive equalization control device includes: a memory and a processor, wherein the memory is used to store a computer program, and the computer program is used to execute the above-mentioned synchronous grid-connected adaptive equalization control method when loaded by the processor.

[0060] A readable storage medium storing a computer program adapted to execute the above-described synchronous grid-connected adaptive equalization control method when loaded by a processor.

[0061] The beneficial effects of this invention are as follows:

[0062] This invention enables high-precision frequency regulation and smooth grid connection under complex operating conditions. While ensuring the stability of the microgrid frequency, it effectively reduces transient impacts during grid connection, significantly improves pre-synchronization speed, and ensures system safety. The invention employs a frequency adaptive control loop and a multivariable decoupling mechanism, transforming the regulation of frequency, voltage, and phase angle into independent and coordinated control loops. This simplifies the system control structure, avoids the oscillation risk caused by multivariable coupling, and further improves control efficiency. Furthermore, this invention can achieve high-precision synchronization under complex operating conditions such as grid voltage distortion and load abrupt changes, while also adapting to the dynamic switching requirements of microgrid off-grid and grid-connected modes. Attached Figure Description

[0063] Figure 1 This is a schematic diagram of the overall process of an embodiment of the present invention;

[0064] Figure 2 This is a schematic diagram of the active power-frequency regulation control loop structure according to an embodiment of the present invention;

[0065] Figure 3 This is a schematic diagram of the reactive power-voltage regulation control loop structure according to an embodiment of the present invention;

[0066] Figure 4 This is a comparison diagram of the simulated waveforms of the VSG output voltage and the grid-side voltage in an embodiment of the present invention;

[0067] Figure 5 This is a graph showing the change in the VSG output current according to an embodiment of the present invention.

[0068] Figure 6 This is a graph showing the change in active power at the output terminal of the VSG according to an embodiment of the present invention.

[0069] Figure 7 This is a graph showing the frequency variation at the output of the VSG in an embodiment of the present invention.

[0070] Figure 8 This refers to the grid-connected signal state of frequency difference, phase angle difference, and voltage amplitude difference in this embodiment of the invention;

[0071] Figure 9 It refers to the grid connection signal state under the traditional grid connection control strategy, which includes frequency difference, phase angle difference, and voltage amplitude difference. Detailed Implementation

[0072] Embodiments of the present invention provide a synchronous grid-connected adaptive equalization control method, such as... Figure 1 As shown, it includes the following steps:

[0073] S1. Acquire the three-phase voltage signals from the VSG side and the grid side. Obtain the grid-side voltage components and VSG-side voltage components in the stationary α-β coordinate system using Clark transformation. Calculate the active power difference between the two sides of the grid-connected switch. Input the active power difference into the frequency PI regulator to generate the pre-synchronization frequency regulation quantity; specifically:

[0074] Real-time acquisition of three-phase voltage signals from the power grid side using high-precision voltage sensors. , , Three-phase voltage signal on the VSG side , , The sampling frequency should be no less than 10kHz to ensure that there is no aliasing of the signal.

[0075] The collected three-phase voltage signals are subjected to Clark transform to obtain the voltage components in the stationary α-β coordinate system. The voltage components in the stationary α-β coordinate system include... Components and Quantity:

[0076] ;

[0077] ;

[0078] in, , These are the grid-side voltages. , Quantity, , VSG side voltage , Quantity.

[0079] Define the active power difference on both sides of the grid-connected switch. The difference in active power is the Euclidean distance between the voltage vectors in the α-β coordinate system. The calculation formula is:

[0080] ;

[0081] The negative sign indicates the direction of power that the VSG needs to compensate the grid for.

[0082] Transfer function of frequency PI regulator for:

[0083] ;

[0084] in, This refers to the gain parameter used for proportional adjustment in a frequency PI controller. This refers to the gain parameter used for integral regulation in a frequency PI controller. For the Laplace operator.

[0085] Pre-synchronization frequency adjustment The calculation formula is:

[0086] ;

[0087] in, This is a time variable used to represent the time dimension during signal acquisition and adjustment. is the integral variable, representing the time delay factor, used to represent the hysteresis characteristics of the active power difference signal.

[0088] S2. Real-time acquisition of VSG side frequency and grid side frequency, calculation of frequency offset and frequency recovery integral coefficient, generation of frequency adaptive compensation amount, and realization of frequency adaptive compensation.

[0089] Frequency offset The calculation formula is:

[0090] ;

[0091] in, For the real-time frequency on the power grid side, This refers to the real-time frequency on the VSG side.

[0092] Frequency recovery integral coefficient The calculation formula is:

[0093] .

[0094] Frequency adaptive compensation amount The calculation formula is:

[0095] ;

[0096] The frequency on the VSG side is adjusted according to the frequency adaptive compensation amount, so that it converges to the frequency on the grid side, thereby realizing frequency adaptive compensation.

[0097] S3. The real-time active power collected from the VSG side, combined with the pre-synchronization frequency adjustment in step S1 and the frequency adaptive compensation in step S2, is used to construct... Figure 2 The active-frequency control loop shown outputs the correction frequency and correction phase angle.

[0098] Correction frequency The calculation formula is:

[0099] ;

[0100] in, For rotational inertia, The damping coefficient is... This is the active power reference value. For the real-time active power collected from the VSG side, This is the initial frequency on the VSG side.

[0101] Correction phase angle The calculation formula is:

[0102] .

[0103] S4. Based on the grid-side voltage component and VSG-side voltage component obtained in step S1, calculate the voltage difference between the two sides of the grid-connected switch, input the voltage difference into the voltage PI regulator, and generate the pre-synchronization voltage regulation amount.

[0104] Voltage difference across the grid-connected switch The calculation formula is:

[0105] ;

[0106] Transfer function of voltage PI regulator for:

[0107] ;

[0108] in, This refers to the gain parameter used for proportional control in a voltage PI regulator. This is the gain parameter used for integral regulation in a voltage PI regulator.

[0109] Pre-synchronization voltage regulation The calculation formula is:

[0110] .

[0111] S5. The real-time reactive power collected on the VSG side, combined with the pre-synchronization voltage regulation in step S4, is used to construct... Figure 3 The reactive power-voltage control loop shown outputs a corrected voltage amplitude.

[0112] Correction voltage amplitude The calculation formula is:

[0113] ;

[0114] in, This is the voltage-controlled droop coefficient. This is the baseline value for reactive power. For the real-time reactive power collected on the VSG side, This is the initial voltage on the VSG side.

[0115] S6. Set the grid connection criterion as follows:

[0116] Frequency difference between the two sides of the grid-connected switch satisfy ,in ;

[0117] Voltage amplitude difference on both sides of the grid-connected switch satisfy ,in ;

[0118] Voltage phase angle difference on both sides of the grid-connected switch satisfy ,in ;

[0119] in, , , Do not set the preset frequency difference threshold, voltage amplitude difference threshold, and phase angle difference threshold. The rated voltage of the power grid is the standard rated voltage value specified in the power system.

[0120] Real-time calculation based on previously obtained parameters , and Continuous monitoring will be conducted. If all three parameters meet the grid connection criteria, the switch can be closed to ensure that the VSG-controlled inverter is successfully and synchronously connected to the public power grid.

[0121] This embodiment provides a synchronous grid-connected adaptive equalization control system for implementing the above method, including:

[0122] Signal acquisition module: used to acquire real-time three-phase voltage signals, real-time active power, real-time reactive power, VSG side frequency, as well as grid side three-phase voltage signals and grid side frequency.

[0123] Coordinate transformation module: Electrically connected to the signal acquisition module, with built-in Clark transformation algorithm, used to receive three-phase voltage signals, perform coordinate transformation and output voltage components in the stationary α-β coordinate system.

[0124] Control processing module: electrically connected to the signal acquisition module and coordinate transformation module, including frequency adaptive submodule, active power-frequency control submodule, voltage regulation submodule, and reactive power-voltage control submodule;

[0125] Frequency Adaptive Submodule: Receives the three-phase voltage signal output from the coordinate transformation module, calculates the active power difference, and generates a pre-synchronization frequency adjustment amount through the built-in frequency PI regulator; simultaneously, it receives the VSG side frequency and grid side frequency output from the signal acquisition module, and calculates the frequency offset and frequency adaptive compensation amount.

[0126] Active-frequency control submodule: Receives pre-synchronization frequency adjustment and frequency adaptive compensation, and outputs correction frequency and correction phase angle;

[0127] Voltage regulation submodule: Receives the voltage component output by the coordinate transformation module, calculates the voltage difference, and generates a pre-synchronization voltage regulation amount through the built-in voltage PI regulator;

[0128] Reactive power-voltage control submodule: Receives real-time reactive power and pre-synchronization voltage regulation from the VSG side, and outputs the corrected voltage amplitude.

[0129] Grid connection execution module: Electrically connected to the control processing module, it detects frequency difference, voltage amplitude difference and phase angle difference in real time. When the grid connection criteria are met, it controls the grid connection switch to close, completing the synchronous access of VSG and the power grid.

[0130] This embodiment provides a synchronous grid-connected adaptive equalization control device, including: a memory and a processor. The memory is used to store a computer program, and the computer program is used to execute the above-described synchronous grid-connected adaptive equalization control method when loaded by the processor.

[0131] This embodiment provides a readable storage medium storing a computer program that is adapted to execute the above-described synchronous grid-connected adaptive equalization control method when loaded by a processor.

[0132] This embodiment uses Matlab / Simulink to build a virtual synchronous generator grid-connected simulation model. The target output power of the VSG is set to 10kW. Initially, the inverter operates in islanded mode and carries a 5kW local load. When the system receives the grid connection command in 0.5 seconds, the controller immediately initiates pre-synchronization logic, gradually adjusting the VSG's output voltage parameters to converge its frequency and phase to the grid reference value. By real-time monitoring of the frequency difference, phase angle difference, and voltage amplitude difference, the system completes the pre-synchronization stage and triggers the grid connection switch closing operation in 0.611 seconds when the synchronization errors of these three parameters drop to 0.1Hz, 5°, and 1.5% of the rated voltage, respectively (all below preset thresholds).

[0133] like Figure 4-5 As shown, the simulation results indicate that the voltage synchronization process on the VSG side was completed 0.611 seconds ago, and no significant transient impact occurred at the moment of grid connection. Figure 6 The dynamic curve of active power on the VSG side shows that the power fluctuation is limited after the grid connection command is triggered. After the switch is closed, the active power smoothly transitions from the initial 5kW to 10kW, with a transition time of only 0.18 seconds. Figure 7 The mid-frequency tracking curve further reveals that the initial frequency (50.25Hz) on the VSG side converges rapidly to the grid frequency (50Hz) through an adaptive compensation mechanism. Figure 8 and Figure 9The grid connection signal states are the frequency difference, phase angle difference, and voltage amplitude difference under the present method and the traditional control strategy, respectively. A state of 1 indicates that the signal meets the grid connection conditions. It can be seen that compared with the traditional control strategy, the present method reduces the synchronization determination time from 0.634 seconds to 0.611 seconds, and the response speed is improved by 17.16%.

[0134] This invention has been described through embodiments. Those skilled in the art will understand that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of this invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, this invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this invention.

Claims

1. A synchronous grid-connected adaptive equalization control method, characterized in that, include: Collect three-phase voltage signals from the VSG side and the grid side, and obtain the grid-side voltage in the stationary α-β coordinate system through Clark transformation. , Components and VSG side voltage , The active power difference between the two sides of the grid-connected switch is calculated and input into the frequency PI regulator to generate the pre-synchronization frequency regulation amount. Collect real-time VSG side frequency and grid side frequency, calculate frequency offset and frequency recovery integral coefficient, and generate frequency adaptive compensation amount; The real-time active power on the VSG side is collected, and the correction frequency and correction phase angle are calculated by combining the pre-synchronization frequency adjustment and frequency adaptive compensation. Based on the voltage components on the grid side and the voltage components on the VSG side, the voltage difference between the two sides of the grid-connected switch is calculated, and the voltage difference is input into the voltage PI regulator to generate the pre-synchronization voltage regulation amount. The real-time reactive power collected on the VSG side is combined with the pre-synchronization voltage regulation amount to calculate the correction voltage amplitude; Using the correction frequency, correction phase angle, and correction voltage amplitude, the frequency difference, voltage amplitude difference, and phase angle difference on both sides of the grid-connected switch are calculated and monitored in real time. When all three satisfy the preset grid connection criteria, the grid-connected switch is closed.

2. The synchronous grid-connected adaptive equalization control method according to claim 1, characterized in that, The calculation of the active power difference on both sides of the grid-connected switch. for: ； in, , These are the grid-side voltages. , Quantity, , VSG side voltage , Quantity; The transfer function of the frequency PI regulator for: ； in, This refers to the gain parameter used for proportional adjustment in a frequency PI controller. This refers to the gain parameter used for integral regulation in a frequency PI controller. For the Laplace operator; The pre-synchronization frequency adjustment amount The calculation formula is: ； in, For time variables, It is the integral variable.

3. The synchronous grid-connected adaptive equalization control method according to claim 2, characterized in that, The frequency offset The calculation formula is: ； in, For the real-time frequency on the power grid side, Real-time frequency on the VSG side; Frequency recovery integral coefficient The calculation formula is: ； Frequency adaptive compensation amount The calculation formula is: 。 4. The synchronous grid-connected adaptive equalization control method according to claim 3, characterized in that, The correction frequency The calculation formula is: ； in, For rotational inertia, The damping coefficient is... This is the active power reference value. For the real-time active power collected from the VSG side, The initial frequency on the VSG side; The corrected phase angle The calculation formula is: 。 5. The synchronous grid-connected adaptive equalization control method according to claim 2, characterized in that, The voltage difference across the grid-connected switch The calculation formula is: ； Transfer function of voltage PI regulator for: ； in, This refers to the gain parameter used for proportional control in a voltage PI regulator. This refers to the gain parameter used for integral regulation in a voltage PI regulator; Pre-synchronization voltage regulation The calculation formula is: 。 6. The synchronous grid-connected adaptive equalization control method according to claim 5, characterized in that, The correction voltage amplitude The calculation formula is: ； in, This is the voltage-controlled droop coefficient. This is the baseline value for reactive power. For the real-time reactive power collected on the VSG side, This is the initial voltage on the VSG side.

7. The synchronous grid-connected adaptive equalization control method according to claim 1, characterized in that, The grid connection criterion is as follows: Frequency difference between the two sides of the grid-connected switch satisfy ,in ; Voltage amplitude difference across the grid-connected switch satisfy ,in ; Voltage phase angle difference on both sides of the grid-connected switch satisfy ,in ; in, , , Do not set the preset frequency difference threshold, voltage amplitude difference threshold, and phase angle difference threshold. This is the rated voltage of the power grid.

8. A synchronous grid-connected adaptive equalization control system, characterized in that, include: Signal acquisition module: used to acquire real-time three-phase voltage signals, real-time active power, real-time reactive power, VSG side frequency, and grid side three-phase voltage signals and grid side frequency; Coordinate transformation module: Electrically connected to the signal acquisition module, with built-in Clark transformation algorithm, used to receive three-phase voltage signals, perform coordinate transformation and output voltage components in the stationary α-β coordinate system; Control processing module: electrically connected to the signal acquisition module and coordinate transformation module, including frequency adaptive submodule, active power-frequency control submodule, voltage regulation submodule, and reactive power-voltage control submodule; Frequency Adaptive Submodule: Receives the three-phase voltage signal output from the coordinate transformation module, calculates the active power difference, and generates a pre-synchronization frequency adjustment amount through the built-in frequency PI regulator; simultaneously, it receives the VSG side frequency and grid side frequency output from the signal acquisition module, and calculates the frequency offset and frequency adaptive compensation amount. Active-frequency control submodule: Receives pre-synchronization frequency adjustment and frequency adaptive compensation, and outputs correction frequency and correction phase angle; Voltage regulation submodule: Receives the voltage component output by the coordinate transformation module, calculates the voltage difference, and generates a pre-synchronization voltage regulation amount through the built-in voltage PI regulator; Reactive power-voltage control submodule: Receives real-time reactive power and pre-synchronization voltage regulation from the VSG side, and outputs the corrected voltage amplitude; Grid connection execution module: Electrically connected to the control processing module, it detects frequency difference, voltage amplitude difference and phase angle difference in real time. When the grid connection criteria are met, it controls the grid connection switch to close, completing the synchronous access of VSG and the power grid.

9. A synchronous grid-connected adaptive equalization control device, characterized in that, include: The memory and processor, wherein the memory is used to store a computer program, and the computer program is used to execute the synchronous grid-connected adaptive equalization control method according to any one of claims 1-7 when loaded by the processor.

10. A readable storage medium, characterized in that, The storage medium contains a computer program that is adapted to execute the synchronous grid-connected adaptive equalization control method according to any one of claims 1-7 when loaded by a processor.

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