VSG-based power grid regulation and control method, device and equipment and storage medium

Abstract

The invention discloses a regulation and control method, device and equipment for a power grid based on a VSG and a storage medium, and relates to the technical field of network construction type converter control, and the method comprises the steps: firstly setting an initial inertia coefficient and an initial damping coefficient, carrying out the frequency deviation detection of the power grid, obtaining a frequency deviation detection result, and if the frequency deviation occurs, carrying out the frequency deviation detection; if yes, adjusting the initial damping coefficient and the initial inertia coefficient to obtain a first damping coefficient and a first inertia coefficient; and inputting the first inertia coefficient and the first damping coefficient into an active control loop mathematical model of the virtual synchronous generator, judging whether the power grid is in a stable state, and transmitting the first inertia coefficient and the first damping coefficient to the power grid if the power grid is in the stable state. According to the method, the inertia coefficient and the damping coefficient are adaptively adjusted, so that the power grid is in a stable state after the first inertia coefficient and the first damping coefficient are transmitted to the power grid.

Description

Technical Field

[0001] The present application relates to the technical field of grid-type converter control, and in particular to a method, device, equipment and storage medium for regulating a power grid based on VSG. Background Art

[0002] A virtual synchronous generator (VSG) strategy has been proposed to simulate the rotational inertia and damping characteristics of synchronous generators, aiming to enhance the frequency support capabilities of microgrids. VSGs simulate the dynamic response of synchronous generators through control algorithms, enabling distributed generation to provide frequency regulation functions similar to those of traditional synchronous generators in microgrids, thereby improving system stability and reliability.

[0003] Traditional VSG strategies typically use fixed control coefficients to simulate the inertia and damping characteristics of synchronous generators. These fixed coefficients cannot be flexibly adjusted under different operating conditions, resulting in limited dynamic regulation performance of the system. Furthermore, the control coefficient is easily affected by frequency measurement errors. Since the determination of the control coefficient depends on the frequency change rate, and the frequency measurement may contain noise or interference, this can cause the control coefficient to be inaccurately amplified or reduced. When the control coefficient is too large, the dynamic response of the VSG becomes too aggressive, potentially causing system oscillation or instability. When the control coefficient is too small, the VSG's regulation capability is insufficient and cannot effectively support the system frequency. This problem seriously affects the robustness and dynamic performance of the VSG, limiting its widespread application in complex microgrid environments. Summary of the Invention

[0004] The present application provides a method, device, equipment and storage medium for regulating the power grid based on VSG, which can improve the flexibility and dynamic adjustment performance of VSG by introducing an adaptive inertia coefficient and damping coefficient based on the system frequency deviation, so that the power grid remains in a stable state.

[0005] To achieve the above objectives, this application adopts the following technical solutions: In a first aspect, the present application provides a method for regulating a power grid based on a VSG, the method comprising: Set the initial inertia coefficient and initial damping coefficient; Perform frequency deviation detection on the power grid and obtain the result of frequency deviation detection; If a frequency deviation occurs, the initial damping coefficient is adjusted to obtain a first damping coefficient; According to the result of the frequency deviation detection, the maximum frequency deviation is obtained, and according to the frequency deviation detector, the time when the maximum frequency deviation occurs is obtained; Determine whether the frequency deviation at time t is less than the maximum frequency deviation and whether time t is less than the time when the maximum frequency deviation occurs, to obtain a third determination result; If the third judgment result indicates that the frequency deviation at time t is less than the maximum frequency deviation and time t is less than the time when the maximum frequency deviation occurs, the initial inertia coefficient is adjusted to obtain a first inertia coefficient; Inputting the first inertia coefficient and the first damping coefficient into the active power control loop mathematical model of the virtual synchronous generator to determine whether the power grid is in a stable state, thereby obtaining a fourth determination result; If the fourth judgment result indicates that the power grid is in a stable state, the first inertia coefficient and the first damping coefficient are transmitted to the power grid.

[0006] In some possible implementations, obtaining, according to the frequency deviation detector, the time when the maximum frequency deviation occurs includes: Use a frequency deviation detector to determine whether the absolute value of the frequency deviation at the tth moment is less than the first deviation threshold and whether the absolute value of the frequency change rate at the tth moment is less than the first change rate threshold. If the absolute value of the frequency deviation at the tth moment is less than the first deviation threshold and the absolute value of the frequency change rate at the tth moment is less than the first change rate threshold, then the tth moment is determined to be the moment when the maximum frequency deviation occurs.

[0007] In some possible implementations, adjusting the initial damping coefficient to obtain the first damping coefficient includes:

[0008] in, is the first damping coefficient, is the initial damping coefficient, is the controllable coefficient of the damping coefficient, is the output function of the active power small signal model of the VSG power controller.

[0009] In some possible implementations, adjusting the initial inertia coefficient to obtain the first inertia coefficient includes:

[0010] in, is the first inertia coefficient, is the initial inertia coefficient, is the controllable coefficient of inertia, is the frequency deviation at moment t, is the maximum frequency deviation, is the moment when the maximum frequency deviation occurs.

[0011] In some possible implementations, the method further includes: If the third judgment result indicates that the frequency deviation at the tth moment is not less than the maximum frequency deviation and the tth moment is not less than the time when the maximum frequency deviation occurs, the initial inertia coefficient is not adjusted.

[0012] In some possible implementations, the method further includes: If the fourth judgment result indicates that the power grid is not in a stable state, the first inertia coefficient is used as the new initial inertia coefficient, and the new initial inertia coefficient is adjusted to obtain a new first inertia coefficient; the first damping coefficient is used as the new initial damping coefficient, and the new initial damping coefficient is adjusted to obtain a new first damping coefficient. In some possible implementations, the method further includes: A mathematical model of an active power control loop of a virtual synchronous generator is constructed, and the inertia coefficient is optimized to obtain a first value range of the inertia coefficient; a first determination result is obtained by determining whether the initial inertia coefficient is within the first value range; and a frequency deviation detection is performed on the power grid if the first determination result indicates that the initial inertia coefficient is not within the first value range. A mathematical model of the active power control loop of the virtual synchronous generator is constructed, and the damping coefficient is optimized to obtain a second value range of the damping coefficient; whether the initial damping coefficient is within the second value range is determined to obtain a second determination result; if the second determination result indicates that the initial damping coefficient is not within the second value range, a frequency deviation detection is performed on the power grid.

[0013] In a second aspect, the present application provides a VSG-based power grid control device, the device comprising: The acquisition module is used to set the initial inertia coefficient and the initial damping coefficient; perform frequency deviation detection on the power grid and obtain the result of the frequency deviation detection; a first judgment module, configured to adjust the initial damping coefficient to obtain a first damping coefficient if a frequency deviation occurs; a second judgment module, configured to obtain a maximum frequency deviation based on a result of the frequency deviation detection, and obtain a time when the maximum frequency deviation occurs based on a frequency deviation detector; determine whether the frequency deviation at time t is less than the maximum frequency deviation and whether time t is less than the time when the maximum frequency deviation occurs, to obtain a third judgment result; if the third judgment result indicates that the frequency deviation at time t is less than the maximum frequency deviation and time t is less than the time when the maximum frequency deviation occurs, adjust the initial inertia coefficient to obtain a first inertia coefficient; input the first inertia coefficient and the first damping coefficient into a mathematical model of an active power control loop of the virtual synchronous generator to determine whether the power grid is in a stable state, to obtain a fourth judgment result; The transmission module is configured to transmit the first inertia coefficient and the first damping coefficient to the power grid if the fourth judgment result indicates that the power grid is in a stable state.

[0014] In a third aspect, the present application provides a computing device, including a memory and a processor; One or more computer programs are stored in the memory, and the one or more computer programs include instructions; when the instructions are executed by the processor, the computing device executes the method as described in any one of the first aspects.

[0015] In a fourth aspect, the present application provides a computer-readable storage medium for storing a computer program for executing the method as described in any one of the first aspects.

[0016] In a fifth aspect, the present application provides a computer program product, which includes one or more computer instructions. When the computer instructions are executed by a computer, the computer executes the method as described in any one of the first aspects.

[0017] It can be seen from the above technical solution that this application has at least the following beneficial effects: In this application, an initial inertia coefficient and an initial damping coefficient are first set. A frequency deviation detection is performed on the power grid to obtain the result of the frequency deviation detection. If a frequency deviation occurs, the initial damping coefficient is adjusted to obtain a first damping coefficient. Then, based on the result of the frequency deviation detection, the maximum frequency deviation is obtained. Then, based on the frequency deviation detector, the time when the maximum frequency deviation occurs is obtained. A determination is made as to whether the frequency deviation at time t is less than the maximum frequency deviation and whether time t is less than the time when the maximum frequency deviation occurs. If the frequency deviation at time t is less than the maximum frequency deviation and time t is less than the time when the maximum frequency deviation occurs, the initial inertia coefficient is adjusted to obtain a first inertia coefficient. The first inertia coefficient and the first damping coefficient are input into the mathematical model of the active power control loop of the virtual synchronous generator to determine whether the power grid is in a stable state. If the power grid is in a stable state, the first inertia coefficient and the first damping coefficient are transmitted to the power grid. Traditional VSG strategies typically use fixed control coefficients to simulate the inertia and damping characteristics of synchronous generators. These fixed coefficients cannot be flexibly adjusted under different operating conditions, resulting in limited dynamic regulation performance of the power grid. Moreover, the control coefficients are easily affected by frequency measurement errors. It can be seen that the present application adaptively adjusts the inertia coefficient and the damping coefficient by changing the frequency, so that after the first inertia coefficient and the first damping coefficient are transmitted to the power grid, the power grid is in a stable state.

[0018] It should be understood that the description of technical features, technical solutions, beneficial effects or similar language in this application does not imply that all features and advantages can be realized in any single embodiment. On the contrary, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution or beneficial effect is included in at least one embodiment. Therefore, the description of a technical feature, technical solution or beneficial effect in this specification does not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions and beneficial effects described in the present embodiment can also be combined in any appropriate manner. Those skilled in the art will understand that the embodiment can be implemented without one or more specific technical features, technical solutions or beneficial effects of a specific embodiment. In other embodiments, additional technical features and beneficial effects can also be identified in specific embodiments that do not embody all embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of an application scenario provided in an embodiment of the present application; Figure 2 A flowchart of a method for controlling a power grid based on a VSG provided in an embodiment of the present application; Figure 3 A schematic diagram of a VSG-based power grid control device provided in an embodiment of the present application; Figure 4 A schematic diagram of a computing device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] The terms "first", "second" and "third" in this application specification and the accompanying drawings are used to distinguish different objects rather than to limit a specific order.

[0021] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0022] To make the description of the following embodiments clear and concise, a brief introduction to the related technologies is first given: The virtual synchronous generator (VSG) is a control technology based on power electronic converters that enables distributed power sources (such as photovoltaic and wind power) to simulate the external characteristics of synchronous generators when connected to the grid. Essentially, it uses a control algorithm to incorporate characteristics similar to synchronous generators, such as inertia and damping, into the inverter control, giving the distributed power source the operating mechanism of a synchronous generator.

[0023] VSGs can simulate the inertial response of synchronous generators. When the grid frequency changes, they provide a certain degree of inertial support, just like a synchronous generator. For example, when the grid frequency drops, the VSG can temporarily increase its output active power by releasing its stored energy, mimicking the rotor inertia of a traditional synchronous generator.

[0024] In a microgrid composed of distributed power sources, VSGs can achieve the proper allocation of active and reactive power according to a given strategy. Different VSGs can automatically coordinate power output based on their own parameters, such as rated power, to ensure the stable operation of the microgrid.

[0025] Because VSGs provide virtual inertia, they enhance the grid's ability to cope with sudden power surges and frequency fluctuations. In a grid containing a large number of distributed generation (DGs), controlling these DGs through VSGs can effectively reduce frequency deviations during grid faults or load changes, mitigating the risk of system collapse.

[0026] Distributed power sources (such as photovoltaic and wind power) are often intermittent and fluctuating. VSG control can better adapt these distributed power sources to the operational requirements of the grid, simulating the characteristics of synchronous generators, making them easier to integrate into traditional grids and reducing impact on the grid.

[0027] Traditional virtual synchronous generator strategies typically use fixed control coefficients to simulate the inertia and damping characteristics of synchronous generators. These fixed coefficients cannot be flexibly adjusted under varying operating conditions, significantly compromising the system's dynamic regulation performance. For example, in the case of sudden load changes in microgrids, the inability to adapt the control coefficients prevents the VSG from responding quickly and stabilizing the system frequency, limiting the system's ability to cope with complex operating conditions. Furthermore, the determination of the control coefficient is highly dependent on the rate of frequency change, and noise and interference are unavoidable in actual frequency measurement. This noise or interference can cause frequency measurement errors, which in turn can lead to inaccurate scaling of the control coefficient. When the control coefficient is too large, the VSG's dynamic response becomes overly aggressive. In extreme cases, this can cause system oscillations and even instability. Conversely, if the control coefficient is too small, the VSG's regulation capability becomes insufficient, making it difficult to effectively support system frequency fluctuations. This issue severely impairs the VSG's robustness and dynamic performance, becoming a major obstacle to its widespread application in complex microgrid environments.

[0028] In view of this, an embodiment of the present application provides a method for controlling a power grid based on a VSG, wherein an initial inertia coefficient and an initial damping coefficient are first set, a frequency deviation detection is performed on the power grid, and a frequency deviation detection result is obtained. If a frequency deviation occurs, the initial damping coefficient is adjusted to obtain a first damping coefficient. Then, based on the frequency deviation detection result, a maximum frequency deviation is obtained. Then, based on the frequency deviation detector, the time when the maximum frequency deviation occurs is obtained. It is determined whether the frequency deviation at time t is less than the maximum frequency deviation and whether time t is less than the time when the maximum frequency deviation occurs. If the frequency deviation at time t is less than the maximum frequency deviation and time t is less than the time when the maximum frequency deviation occurs, the initial inertia coefficient is adjusted to obtain a first inertia coefficient. The first inertia coefficient and the first damping coefficient are input into the active power control loop mathematical model of the virtual synchronous generator to determine whether the power grid is in a stable state. If the power grid is in a stable state, the first inertia coefficient and the first damping coefficient are transmitted to the power grid. It can be seen that the present application adaptively adjusts the inertia coefficient and the damping coefficient through frequency changes, so that after the first inertia coefficient and the first damping coefficient are transmitted to the power grid, the power grid is in a stable state. In order to make the technical solution of this application clearer and easier to understand, the application scenarios of the technical solution of this application are introduced below with reference to the accompanying drawings. Figure 1 As shown in the figure, this figure is a schematic diagram of an application scenario provided by an embodiment of the present application.

[0029] In this application scenario, the left side of the figure shows the wind power generation part. The generated electricity passes through the DC / AC (AC / DC conversion) link, and then is connected to the grid through capacitors and inverters. The three-phase current and three-phase voltage output by the inverter and the three-phase current on the grid side are obtained and transmitted to the control part. The active power reference value and reactive power reference value are then input and output to the PWM generator through the control part, and then transmitted to the inverter. The control part in the figure mainly controls the inverter output to make it have the characteristics of a virtual synchronous generator.

[0030] Among them, the control part includes voltage and current dual closed-loop control and virtual synchronization and control. The voltage and current dual closed-loop control is a control strategy that includes a voltage outer loop and a current inner loop. By adjusting the inverter output voltage and current, it reaches the desired value. The outer loop voltage control is mainly based on the given voltage reference value Uref and the actual measured output voltage udq. After proportional integral adjustment, the reference value of the current inner loop is generated; the current inner loop compares this reference value with the actual measured current idq, and again through proportional integral adjustment, outputs the control signal to the PWM generator. This process is closely coordinated to ensure that the VSG outputs stable voltage and current.

[0031] The following is Figure 1 Explain the structure in .

[0032] The leftmost icon in the image represents wind power generation, which is the source of power for the entire system; DC / AC: represents the DC-AC converter, which converts the DC power generated by the wind turbine into AC power; i abc Represents the three-phase current, which is the representation of the three-phase current output by the inverter in the natural coordinate system (abc coordinate system); u abc Represents the three-phase voltage, which is the representation of the three-phase voltage at the inverter output end in the natural coordinate system (abc coordinate system); i gabc Represents the three-phase current on the grid side, that is, the representation of the three-phase current flowing into the grid in the natural coordinate system (abc coordinate system); i dq 、u dq and ig dq It converts the three-phase current and voltage in the abc coordinate system into the current and voltage representation in the synchronous rotating coordinate system (dq coordinate system) through dq transformation (Park transformation), which facilitates the implementation and analysis of the control algorithm. V represents the voltage amplitude and θ represents the phase angle, which are important parameters in the control process. Virtual synchronization and control: This module implements the virtual synchronous generator control algorithm and simulates the operating characteristics of the synchronous generator based on given reference values and measured values. P ref , Q ref : are active power reference value and reactive power reference value, respectively, as the target setting value of control; w ref is the angular frequency reference value, U ref It is the voltage reference value and also an important reference setting quantity in the control process.

[0033] In order to make the technical solution of this application clearer and easier to understand, the following describes a method for controlling the power grid based on VSG provided by an embodiment of this application in combination with the above application scenarios. Figure 2 As shown in FIG, this figure is a flow chart of a VSG-based power grid control method provided in an embodiment of the present application. The VSG-based power grid control method includes: S201. Set the initial inertia coefficient and initial damping coefficient.

[0034] First, initial values of the inertia coefficient and the damping coefficient are set, and the initial inertia coefficient and the initial damping coefficient are defined by considering the characteristics of a typical second-order transfer function. Then, a mathematical model of the active power control loop of the virtual synchronous generator is constructed, and the inertia coefficient is optimized to obtain a first value range of the inertia coefficient. It is determined whether the initial inertia coefficient is within the first value range to obtain a first determination result. If the first determination result indicates that the initial inertia coefficient is not within the first value range, a frequency deviation detection is performed on the power grid. A mathematical model of the active power control loop of the virtual synchronous generator is constructed, and the damping coefficient is optimized to obtain a second value range of the damping coefficient; whether the initial damping coefficient is within the second value range is determined to obtain a second determination result; if the second determination result indicates that the initial damping coefficient is not within the second value range, a frequency deviation detection is performed on the power grid.

[0035] In the embodiment of the present application, the mathematical model of the active power control loop of the virtual synchronous generator is composed of the rotor motion equation of the VSG model, the VSG small signal model and the closed-loop transfer function, and is calculated by formulas (1)-(11).

[0036] Through the second-order transient model of the synchronous generator's motion equation and the relationship between power and torque, the rotor motion equation of the VSG model is derived, as shown in formula (1): (1) In the formula is the mechanical torque, is the electromagnetic torque, J is the first inertia coefficient, D is the first damping coefficient, is the VSG mechanical angular velocity, is the grid synchronization angular velocity, and formula (2) is obtained from formula (1): (2) In the formula is the mechanical power input, To analyze the influence of different parameters on VSG characteristics for electromagnetic power output, an overall control structure including power control loop and voltage and current control loop is constructed. To simulate the dynamic response of the power grid, a small signal model is used to obtain a new control strategy so that when a disturbance occurs in the system, the VSG should immediately adjust its output to maintain the stability of the power grid. The VSG small signal model is shown in formula (3): (3) in, is the value of active power instruction, is the value of active power, is the initial angular velocity, is the angle obtained by integrating the angular velocity.

[0037] From the main circuit diagram of the grid-connected grid-connected converter, we can see that the following relationship exists as shown in formula (4): (4) In the formula is the vector form of the converter electromotive force, is the vector form of the grid side voltage, Represents the vector form of phase a current in a three-phase circuit, is the equivalent resistance from the converter output point to the grid connection point, is the equivalent inductance from the converter output point to the grid connection point. Therefore, the converter unidirectional output active power can be obtained as shown in formula (5): (5) The grid side voltage is used as the reference voltage with a phase angle of 0°. is the phase angle of the converter output voltage relative to the grid voltage, is the phase angle of the resistance inductance, , is the resistance, is the reactance, is the total impedance, is the converter electromotive force, is the grid side voltage. Since the inductance is much greater than the resistance in practice, it can be approximately considered as pure inductance. =π / 2, the phase angle difference between the output voltage of the converter and the grid voltage is usually very small, so it can be considered , so the above active power formula can be simplified to formula (6): (6) According to the control block diagram of the virtual synchronous machine active power control link and through Laplace transform, the closed-loop transfer function can be obtained as formula (7):

[0038] In the formula is the converter output voltage. It can be seen that the closed-loop transfer function is a typical second-order equation. To simplify the calculation, let , replace D with (kf + ) The simplified transfer function is formula (8):

[0039] In this application, the influence of different moments of inertia and damping coefficients on the stability of the VSG system is analyzed based on the root locus method. The root locus analysis steps include: first, determining the open-loop transfer function of the VSG system; then, by changing the system parameters (such as inertia and damping coefficients), observing the changes in the poles of the closed-loop system, and obtaining the range of values of the inertia coefficient and damping coefficient, thereby evaluating the stability and dynamic response of the system.

[0040] S202: Perform frequency deviation detection on the power grid to obtain a frequency deviation detection result.

[0041] A frequency deviation detector is used to determine whether the absolute value of the frequency deviation at time t is less than the first deviation threshold and whether the absolute value of the frequency change rate at time t is less than the first change rate threshold. If the absolute value of the frequency deviation at time t is less than the first deviation threshold and the absolute value of the frequency change rate at time t is less than the first change rate threshold, time t is determined to be the time when the maximum frequency deviation occurs. As shown in formula (9): (9) If the frequency deviation The absolute value is less than 0.001Hz, and the frequency change rate The absolute value of is less than 0.01 Hz / s, which means that the maximum frequency deviation occurs at the moment Captured, the lowest frequency point is detected when the threshold is met, and marked This method may detect the frequency minimum slightly later or earlier than the actual frequency minimum, but it will not have a serious impact on the frequency support capability because the output power of the VSG will vary excessively.

[0042] S203: If a frequency deviation occurs, adjust the initial damping coefficient and the initial inertia coefficient to obtain a first damping coefficient and a first inertia coefficient.

[0043] If frequency deviation occurs, the initial damping coefficient is adaptively adjusted, as shown in formula (10): (10) in, is the first damping coefficient, is the initial damping coefficient, is the controllable coefficient of the damping coefficient, is the output function of the active power small signal model of the VSG power controller.

[0044] If a frequency deviation occurs, determining whether the frequency deviation at time t is less than the maximum frequency deviation and whether time t is less than the time when the maximum frequency deviation occurs, to obtain a third determination result; If the third judgment result indicates that the frequency deviation at the t-th moment is less than the maximum frequency deviation and the t-th moment is less than the time when the maximum frequency deviation occurs, the initial inertia coefficient is adjusted to obtain the first inertia coefficient; if the third judgment result indicates that the frequency deviation at the t-th moment is not less than the maximum frequency deviation and the t-th moment is not less than the time when the maximum frequency deviation occurs, the initial inertia coefficient is confirmed as the first inertia coefficient.

[0045] The calculation process for determining the first inertia coefficient is shown in formula (11):

[0046] in, is the first inertia coefficient, is the initial inertia coefficient, is the controllable coefficient of inertia, is the frequency deviation at moment t, is the maximum frequency deviation, is the moment when the maximum frequency deviation occurs.

[0047] When the system frequency deviation occurs, the control algorithm adjusts the initial inertia coefficient and initial damping coefficient according to the size and change trend of the deviation to achieve rapid response and effective suppression of the system frequency. According to the system frequency trajectory after the disturbance, it can be found that in the early stage of the disturbance, the frequency change depends on the rotational inertia of the power system. After that, the system frequency deviation becomes larger and the frequency should be prevented from decreasing. After the disturbance occurs in the power grid, the frequency begins to decrease and according to the frequency trajectory, the definition of the adaptive inertia coefficient can be defined as two parts: The first part is before the frequency reaches its lowest point, and until it reaches the lowest point, the system needs additional inertia to resist the rapid drop in frequency. At the same time, in this stage, the inertia coefficient will increase linearly according to the frequency deviation to increase the inertia support of the VSG to the grid and help slow down the speed of frequency drop. The purpose of the first part is to provide additional inertia support during the frequency drop to reduce unbalanced power and suppress the rapid drop in frequency. The second part is that after the maximum frequency deviation, when the grid frequency reaches the lowest point, the system needs a control strategy to restore the frequency and prevent excessive rebound. At this stage, the inertia coefficient will decrease from the increased state back to the initial inertia coefficient to avoid negative effects during frequency recovery, such as excessive frequency rise or oscillation; the purpose of the second part is to appropriately reduce the inertia contribution of the VSG after the frequency begins to recover, so as to promote frequency stabilization and reduce possible overcorrection, ensuring a smooth transition of the grid frequency.

[0048] In this embodiment of the present application, to ensure the stability of the VSG (virtual synchronous generator), simulation tests were conducted on power grids under different conditions to limit b and k. In this way, the balance between maintaining system stability and optimizing frequency support capability was accurately identified. Specifically, by limiting the values of b and k, the adjustment range of J and D was effectively controlled, allowing the VSG to avoid instability caused by excessively large control coefficients when providing support to the power grid. Therefore, the adaptive coefficient proposed in this embodiment can both improve frequency support capability and avoid VSG instability, achieving dual optimization of technical performance.

[0049] S204: Input the first inertia coefficient and the first damping coefficient into the active power control loop mathematical model of the virtual synchronous generator.

[0050] The adaptively adjusted first inertia coefficient and first damping coefficient are input into the active power control loop mathematical model of the virtual synchronous generator to determine whether the first inertia coefficient is within the first value range and whether the first damping coefficient is within the second value range, that is, to execute S205.

[0051] S205: Determine whether the power grid is in a stable state.

[0052] determining whether the power grid is in a stable state, and obtaining a fourth determination result; If the fourth judgment result indicates that the power grid is in a stable state, executing S206; If the fourth judgment result indicates that the power grid is not in a stable state, return to S202, use the first inertia coefficient as the new initial inertia coefficient, adjust the new initial inertia coefficient to obtain a new first inertia coefficient; use the first damping coefficient as the new initial damping coefficient, adjust the new initial damping coefficient to obtain a new first damping coefficient.

[0053] S206: Transmit the first inertia coefficient and the first damping coefficient to the power grid.

[0054] Based on the above content, this application proposes an improved VSG strategy with adaptive inertia and damping coefficients. When the frequency deviation increases during the operation of the power grid, the control coefficient involved in this strategy will self-adaptively adjust the inertia coefficient and damping coefficient according to the preset algorithm logic. This dynamic adjustment mechanism is intended to give VSG greater flexibility, enabling it to respond more quickly and effectively to changes in the grid frequency, thereby improving its support for the grid frequency. Taking a real-world scenario as an example, when the grid load suddenly increases, causing the frequency to drop faster, the control coefficient increases, and the VSG can quickly output more power, providing strong support for the stability of the grid frequency. In terms of the inertia coefficient, this application fully takes into account the complexity of grid frequency changes. When the system detects that the frequency is in a low state, the inertia coefficient will automatically return to the initial value. This is to prevent the adverse effects on the frequency rebound period from being ignored due to the inertia coefficient being in an unreasonable state of large or small during the frequency adjustment process. For example, if the inertia coefficient remains at a large value when the frequency is low, it may cause the VSG to respond slowly when the frequency rebounds and fail to keep up with the changing trend of the grid frequency in time, thereby affecting the overall stability of the grid. As can be seen, this application adaptively adjusts the inertia coefficient and damping coefficient through real-time monitoring and precise analysis of grid frequency changes. After a series of optimization and regulation, the first inertia coefficient and the first damping coefficient, after being transmitted to the grid, can effectively promote the balance and distribution of power within the grid, ensuring that the grid is always in a stable and reliable state of operation.

[0055] The embodiment of the present application also provides a VSG-based power grid control device, such as Figure 3 As shown, this figure is a schematic diagram of a VSG-based power grid control device provided in an embodiment of the present application, the device includes: an acquisition module 301, a first judgment module 302, a second judgment module 303 and a transmission module 304; The acquisition module 301 is used to set the initial inertia coefficient and the initial damping coefficient; perform frequency deviation detection on the power grid and obtain the result of the frequency deviation detection; A first judgment module 302 is configured to adjust the initial damping coefficient to obtain a first damping coefficient if a frequency deviation occurs; The second judgment module 303 is configured to obtain a maximum frequency deviation based on the result of the frequency deviation detection, and obtain a time when the maximum frequency deviation occurs based on the frequency deviation detector; determine whether the frequency deviation at time t is less than the maximum frequency deviation and whether time t is less than the time when the maximum frequency deviation occurs, to obtain a third judgment result; if the third judgment result indicates that the frequency deviation at time t is less than the maximum frequency deviation and time t is less than the time when the maximum frequency deviation occurs, adjust the initial inertia coefficient to obtain a first inertia coefficient; input the first inertia coefficient and the first damping coefficient into the active power control loop mathematical model of the virtual synchronous generator to determine whether the power grid is in a stable state, to obtain a fourth judgment result; The transmission module 304 is configured to transmit the first inertia coefficient and the first damping coefficient to the power grid if the fourth judgment result indicates that the power grid is in a stable state.

[0056] In some possible implementations, the second determining module 303 is specifically configured to obtain, according to the frequency deviation detector, the time when the maximum frequency deviation occurs, including: Use a frequency deviation detector to determine whether the absolute value of the frequency deviation at the tth moment is less than the first deviation threshold and whether the absolute value of the frequency change rate at the tth moment is less than the first change rate threshold. If the absolute value of the frequency deviation at the tth moment is less than the first deviation threshold and the absolute value of the frequency change rate at the tth moment is less than the first change rate threshold, then the tth moment is determined to be the moment when the maximum frequency deviation occurs.

[0057] In some possible implementations, the first determining module 302 is specifically configured to adjust the initial damping coefficient to obtain the first damping coefficient, including:

[0058] in, is the first damping coefficient, is the initial damping coefficient, is the controllable coefficient of the damping coefficient, is the output function of the active power small signal model of the VSG power controller.

[0059] In some possible implementations, the second determining module 303 is specifically configured to adjust the initial inertia coefficient to obtain the first inertia coefficient, including:

[0060] in, is the first inertia coefficient, is the initial inertia coefficient, is the controllable coefficient of inertia, is the frequency deviation at moment t, is the maximum frequency deviation, is the moment when the maximum frequency deviation occurs.

[0061] In some possible implementations, the second judgment module 303 is further configured to not adjust the initial inertia coefficient if the third judgment result indicates that the frequency deviation at time t is not less than the maximum frequency deviation and time t is not less than the time when the maximum frequency deviation occurs.

[0062] In some possible implementations, the second judgment module 303 is further configured to, if the fourth judgment result indicates that the power grid is not in a stable state, use the first inertia coefficient as the new initial inertia coefficient, adjust the new initial inertia coefficient, and obtain a new first inertia coefficient; and use the first damping coefficient as the new initial damping coefficient, adjust the new initial damping coefficient, and obtain a new first damping coefficient. In some possible implementations, the acquisition module 301 is specifically used to construct a mathematical model of the active power control loop of the virtual synchronous generator, optimize the inertia coefficient, and obtain a first value range of the inertia coefficient; determine whether the initial inertia coefficient is within the first value range, and obtain a first judgment result; if the first judgment result indicates that the initial inertia coefficient is not within the first value range, perform frequency deviation detection on the power grid; construct a mathematical model of the active power control loop of the virtual synchronous generator, optimize the damping coefficient, and obtain a second value range of the damping coefficient; determine whether the initial damping coefficient is within the second value range, and obtain a second judgment result; if the second judgment result indicates that the initial damping coefficient is not within the second value range, perform frequency deviation detection on the power grid.

[0063] The present application also provides a computing device. Figure 4 As shown, this figure is a schematic diagram of a computing device provided by an embodiment of the present application, wherein the computing device 400 includes a bus 401, a processor 402, a communication interface 403, and a memory 404. The processor 402, the memory 404, and the communication interface 403 communicate with each other via the bus 401.

[0064] The bus 401 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 4 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0065] The processor 402 may be any one or more of a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor (MP), or a digital signal processor (DSP).

[0066] The communication interface 403 is used for communicating with the outside.

[0067] Memory 404 may include volatile memory, such as random access memory (RAM). Memory 404 may also include non-volatile memory, such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid state drive (SSD).

[0068] The memory 404 stores executable codes, and the processor 402 executes the executable codes to perform the aforementioned VSG-based power grid control method.

[0069] Embodiments of the present application also provide a computer-readable storage medium. The computer-readable storage medium can be any available medium capable of being stored by a computing device, or a data storage device such as a data center that contains one or more available media. The available medium can be a magnetic medium (e.g., a floppy disk, hard disk, or magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive). The computer-readable storage medium includes instructions that instruct the computing device to execute the aforementioned VSG-based power grid control method.

[0070] The present application also provides a computer program product comprising one or more computer instructions that, when loaded and executed on a computing device, fully or partially generate the process or function described in the present application.

[0071] The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer or data center to another website, computer or data center via wired (e.g., coaxial cable, optical fiber) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0072] When the computer program product is executed by a computer, the computer performs any of the aforementioned methods for regulating a power grid based on a VSG. The computer program product may be a software installation package, and when any of the aforementioned methods for regulating a power grid based on a VSG is needed, the computer program product may be downloaded and executed on the computer.

[0073] The descriptions of the processes or structures corresponding to the above figures have different emphases. For parts that are not described in detail in a certain process or structure, please refer to the relevant descriptions of other processes or structures.

[0074] The above description is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed in the present application should be included in the protection scope of the present application.

Claims

1. A method for regulating a power grid based on VSG, characterized in that: The method comprises: Set the initial inertia coefficient and initial damping coefficient; Perform frequency deviation detection on the power grid and obtain the result of frequency deviation detection; If a frequency deviation occurs, the initial damping coefficient is adjusted to obtain a first damping coefficient; According to the result of the frequency deviation detection, the maximum frequency deviation is obtained, and according to the frequency deviation detector, the time when the maximum frequency deviation occurs is obtained; Determine whether the frequency deviation at time t is less than the maximum frequency deviation and whether time t is less than the time when the maximum frequency deviation occurs, to obtain a third determination result; If the third judgment result indicates that the frequency deviation at time t is less than the maximum frequency deviation and time t is less than the time when the maximum frequency deviation occurs, the initial inertia coefficient is adjusted to obtain a first inertia coefficient; Inputting the first inertia coefficient and the first damping coefficient into the active power control loop mathematical model of the virtual synchronous generator to determine whether the power grid is in a stable state, thereby obtaining a fourth determination result; If the fourth judgment result indicates that the power grid is in a stable state, the first inertia coefficient and the first damping coefficient are transmitted to the power grid.

2. The method according to claim 1, characterized in that The step of obtaining the time when the maximum frequency deviation occurs according to the frequency deviation detector includes: Use a frequency deviation detector to determine whether the absolute value of the frequency deviation at the tth moment is less than the first deviation threshold and whether the absolute value of the frequency change rate at the tth moment is less than the first change rate threshold. If the absolute value of the frequency deviation at the tth moment is less than the first deviation threshold and the absolute value of the frequency change rate at the tth moment is less than the first change rate threshold, then the tth moment is determined to be the moment when the maximum frequency deviation occurs.

3. The method according to claim 1, characterized in that The adjusting the initial damping coefficient to obtain the first damping coefficient includes: in, is the first damping coefficient, is the initial damping coefficient, is the controllable coefficient of the damping coefficient, is the output function of the active power small signal model of the VSG power controller.

4. The method according to claim 1, wherein The adjusting the initial inertia coefficient to obtain the first inertia coefficient includes: in, is the first inertia coefficient, is the initial inertia coefficient, is the controllable coefficient of inertia, is the frequency deviation at moment t, is the maximum frequency deviation, is the moment when the maximum frequency deviation occurs.

5. The method according to claim 1, wherein The method further comprises: If the third judgment result indicates that the frequency deviation at the tth moment is not less than the maximum frequency deviation and the tth moment is not less than the time when the maximum frequency deviation occurs, the initial inertia coefficient is not adjusted.

6. The method according to claim 1, characterized in that The method further comprises: If the fourth judgment result indicates that the power grid is not in a stable state, the first inertia coefficient is used as the new initial inertia coefficient, and the new initial inertia coefficient is adjusted to obtain a new first inertia coefficient; the first damping coefficient is used as the new initial damping coefficient, and the new initial damping coefficient is adjusted to obtain a new first damping coefficient.

7. The method according to claim 1, characterized in that The method further comprises: A mathematical model of an active power control loop of a virtual synchronous generator is constructed, and the inertia coefficient is optimized to obtain a first value range of the inertia coefficient; a first determination result is obtained by determining whether the initial inertia coefficient is within the first value range; and a frequency deviation detection is performed on the power grid if the first determination result indicates that the initial inertia coefficient is not within the first value range. A mathematical model of the active power control loop of the virtual synchronous generator is constructed, and the damping coefficient is optimized to obtain a second value range of the damping coefficient; whether the initial damping coefficient is within the second value range is determined to obtain a second determination result; if the second determination result indicates that the initial damping coefficient is not within the second value range, a frequency deviation detection is performed on the power grid.

8. A VSG-based power grid control device, characterized in that: The device comprises: The acquisition module is used to set the initial inertia coefficient and the initial damping coefficient; perform frequency deviation detection on the power grid and obtain the result of the frequency deviation detection; a first judgment module, configured to adjust the initial damping coefficient to obtain a first damping coefficient if a frequency deviation occurs; a second judgment module, configured to obtain a maximum frequency deviation based on a result of the frequency deviation detection, and obtain a time when the maximum frequency deviation occurs based on a frequency deviation detector; determine whether the frequency deviation at time t is less than the maximum frequency deviation and whether time t is less than the time when the maximum frequency deviation occurs, to obtain a third judgment result; if the third judgment result indicates that the frequency deviation at time t is less than the maximum frequency deviation and time t is less than the time when the maximum frequency deviation occurs, adjust the initial inertia coefficient to obtain a first inertia coefficient; input the first inertia coefficient and the first damping coefficient into a mathematical model of an active power control loop of the virtual synchronous generator to determine whether the power grid is in a stable state, to obtain a fourth judgment result; The transmission module is configured to transmit the first inertia coefficient and the first damping coefficient to the power grid if the fourth judgment result indicates that the power grid is in a stable state.

9. A computing device, characterized in that including memory and processor; One or more computer programs are stored in the memory, and the one or more computer programs include instructions; when the instructions are executed by the processor, the computing device executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium is used to store a computer program, and the computer program is used to execute the method according to any one of claims 1 to 7.

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