Control method and device of network equipment, controller, equipment and medium

Abstract

The application discloses a network-constructing device control method and device, a controller, a device and a medium, and belongs to the technical field of wind power. The method comprises the following steps: based on the impedance of a grid-side converter to a power grid, a preset inertia time constant and a preset angular velocity parameter, the damping coefficient of an active power synchronous ring is obtained by using the second-order system characteristics of the active power synchronous ring; the active power synchronous operation is performed according to the damping coefficient, the inertia time constant and the control parameter of the active power synchronous ring, so that the internal electromotive force phase of the network-constructing device is obtained; the reactive power closed-loop control operation is performed according to the control parameter of the reactive power ring, so that the internal electromotive force amplitude of the network-constructing device is obtained; and the PWM signal generated based on the internal electromotive force phase and the internal electromotive force amplitude is used to control the operation of the grid-side converter. According to the embodiment of the application, the safety and reliability of the power system can be improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wind power, and particularly relates to a control method and device of grid-forming equipment, a controller, equipment and a medium. BACKGROUND

[0002] With the development of clean energy technologies such as wind power generation technology and photovoltaic power generation technology, the proportion of clean energy equipment such as wind turbines and photovoltaic equipment in the power system is gradually increasing, which makes the power system including clean energy equipment and the power grid have the trend of reduced inertia and weakened strength. In order to cope with power demand and environmental pressure, a grid-forming control strategy can be used to provide damping and inertia for the power system by using grid-forming equipment, which can quickly respond when the grid frequency changes and support the stability of the power system.

[0003] However, due to the difference in the structure of the power system, the strength of the power grid in different regions of the power system is different, which will cause the active power response characteristics of the grid-forming equipment to be different under different grid strengths when the grid frequency changes, and the support characteristics of the power grid are inconsistent, thereby causing the power system to have a risk of instability and reducing the safety and reliability of the power system. SUMMARY

[0004] The embodiments of the application provide a control method, device, controller, equipment and medium of grid-forming equipment, which can improve the safety and reliability of the power system.

[0005] In a first aspect, the embodiments of the application provide a control method of grid-forming equipment, the grid-forming equipment including a grid-side converter, the grid-side converter being configured to be connected to a power grid; the method comprising: based on the impedance between the grid-side converter and the power grid, a preset inertia time constant and a preset angular velocity parameter, obtaining a damping coefficient of an active power synchronization ring by using the second-order system characteristics of the active power synchronization ring; performing operation according to the damping coefficient, the inertia time constant and the control parameters of the active power synchronization ring to obtain an internal electromotive force phase of the grid-forming equipment; performing reactive power closed-loop control operation according to the control parameters of the reactive power ring to obtain an internal electromotive force amplitude of the grid-forming equipment; and controlling the grid-side converter to operate by using a PWM signal generated based on the internal electromotive force phase and the internal electromotive force amplitude.

[0006] In some possible embodiments, the damping coefficient of the active power synchronization loop is obtained based on an impedance between the grid-side converter and the power grid, a preset inertia time constant, and a preset angular velocity parameter, by using a second-order system characteristic of the active power synchronization loop, including: obtaining a target intermediate parameter according to the impedance between the grid-side converter and the power grid, the inertia time constant, the angular velocity parameter, and the second-order system characteristic; determining a target damping ratio corresponding to the target intermediate parameter in a pre-established damping corresponding relationship table, the damping corresponding relationship table including a corresponding relationship between the damping ratio and a value range of the intermediate parameter; and obtaining the damping coefficient according to the target damping ratio, the angular velocity parameter, the inertia time constant, the impedance between the grid-side converter and the power grid, and the second-order system characteristic.

[0007] In some possible embodiments, before determining the target damping ratio corresponding to the target intermediate parameter in the pre-established damping corresponding relationship, the method further includes: obtaining a plurality of different damping ratios, and calculating a value range of the intermediate parameter corresponding to the plurality of different damping ratios according to the second-order system characteristic and the plurality of different damping ratios; and establishing the damping corresponding relationship table according to the plurality of different damping ratios and the value range of the intermediate parameter corresponding to the plurality of different damping ratios.

[0008] In some possible embodiments, the determining the target damping ratio corresponding to the target intermediate parameter in the pre-established damping corresponding relationship table includes: determining a value range of the intermediate parameter into which the target intermediate parameter falls in the damping corresponding relationship table; and determining the damping ratio corresponding to the value range of the intermediate parameter into which the target intermediate parameter falls in the damping corresponding relationship table as the target damping ratio.

[0009] In some possible embodiments, the angular velocity parameter includes a cutoff angular velocity of the active power synchronization loop and a rated angular velocity of the power grid.

[0010] In some possible embodiments, the control parameter of the active power synchronization loop includes a measured active power of the grid-side converter, a reference active power of the grid-side converter, an internal electromotive force angular velocity, and a rated angular velocity of the power grid.

[0011] The active power synchronization operation is performed according to the damping coefficient, the inertia time constant, and the control parameter of the active power synchronization loop, to obtain an internal electromotive force phase of the grid-connected device, including: obtaining a torque increment of the grid-connected device according to a difference between the reference active power and the measured active power, and the internal electromotive force angular velocity; obtaining an angular velocity increment according to the torque increment, the inertia time constant, and the damping coefficient; and performing integral operation on a sum of the rated angular velocity and the angular velocity increment, to obtain the internal electromotive force phase.

[0012] In some possible embodiments, the control parameter of the reactive power loop includes a measured reactive power of the grid-side converter, a reference reactive power of the grid-side converter, and a rated voltage of the grid-connected device.

[0013] A reactive power closed-loop control operation is performed according to the control parameters of the reactive power loop to obtain the internal potential amplitude of the meshing type device, including: performing a closed-loop control operation on the difference between the reference reactive power and the measured reactive power to obtain a voltage increment of the meshing type device, the closed-loop control operation including at least one of a proportional operation, an integral operation, and a differential operation; and determining the sum of the voltage increment and the rated voltage as the internal potential amplitude.

[0014] In a second aspect, an embodiment of the present application provides a control device for a meshed device, which is applied to the meshed device, wherein the meshed device includes a grid-side converter, which is configured to be connected to a power grid; the device includes: a damping coefficient adjustment module, which is used to obtain the damping coefficient of the active power synchronization loop based on the impedance between the grid-side converter and the power grid, a preset inertia time constant and a preset angular velocity parameter, using the second-order system characteristics of the active power synchronization loop; a phase determination module, which is used to perform active power synchronization operations according to the damping coefficient, the inertia time constant and the control parameters of the active power synchronization loop to obtain the internal potential phase of the meshed device; an amplitude determination module, which is used to perform reactive power closed-loop control operations according to the control parameters of the reactive power loop to obtain the internal potential amplitude of the meshed device; and a control module, which is used to control the operation of the grid-side converter using a PWM signal generated based on the internal potential phase and the internal potential amplitude.

[0015] In a third aspect, an embodiment of the present application provides a controller for a networking-type equipment, comprising: a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, the control method for the networking-type equipment of the first aspect is implemented.

[0016] In a fourth aspect, an embodiment of the present application provides a meshing device, comprising: a grid-side converter, the output end of which is configured to be connected to a power grid; and a controller of the meshing device of the third aspect, which is connected to the grid-side converter.

[0017] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium having computer program instructions stored thereon. When the computer program instructions are executed by a processor, the control method of the networking device of the first aspect is implemented.

[0018] The embodiment of the application provides a control method and device of grid-connected equipment, a controller, equipment and a medium, which can obtain a damping coefficient of an active power synchronous ring based on impedance, inertial time constant and angular velocity parameters of a grid-side converter to a power grid, the damping coefficient is matched with the impedance between the grid-side converter and the power grid. According to the damping coefficient, the inertial time constant and control parameters of the active power synchronous ring, an internal electromotive force phase of the grid-connected equipment is obtained. According to control parameters of a reactive power ring, an internal electromotive force amplitude of the grid-connected equipment is obtained. Different damping coefficients of the active power synchronous ring are obtained according to different impedance between the grid-side converter and the power grid, the internal electromotive force phase is affected by the damping coefficient, so that the PWM signal generated by combining the internal electromotive force phase and the internal electromotive force amplitude controls the grid-side converter, the predictability of the active power response characteristic of the grid-connected equipment under different power grid strengths is realized, the active power response characteristic of the grid-connected equipment under different power grid strengths is consistent or tends to be consistent, and the instability risk of the power system is reduced or even avoided, and the safety and reliability of the power system are improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings required to be used in the embodiments of the application will be briefly introduced below. Those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0020] Figure 1 A structural schematic diagram of an example of the grid-connected equipment provided by the embodiment of the application is shown in the figure.

[0021] Figure 2 A flowchart of the control method of the grid-connected equipment provided by the embodiment of the application is shown in the figure.

[0022] Figure 3 A schematic diagram of an example of the active power response of the grid-connected equipment under different SCRs obtained by the control method with a fixed damping coefficient is shown in the figure.

[0023] Figure 4 A schematic diagram of an example of the active power response of the grid-connected equipment obtained by the control method with the damping coefficient self-adjusted in the embodiment of the application is shown in the figure.

[0024] Figure 5 A flowchart of the control method of the grid-connected equipment provided by another embodiment of the application is shown in the figure.

[0025] Figure 6 A schematic diagram of an example of the active power ring synchronous control provided by the embodiment of the application is shown in the figure.

[0026] Figure 7 A schematic diagram of an example of the reactive power ring control provided by the embodiment of the application is shown in the figure.

[0027] Figure 8 A schematic diagram of an example of network-constructing device control provided by an embodiment of the present application;

[0028] Figure 9 A structural schematic diagram of a control device of a network-constructing device provided by an embodiment of the present application;

[0029] Figure 10 A structural schematic diagram of a controller of a network-constructing device provided by an embodiment of the present application;

[0030] Figure 11 A structural schematic diagram of a network-constructing device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0031] Features and exemplary embodiments of various aspects of the present application will be described in detail below, in order to make the purposes, technical solutions and advantages of the present application more clear and apparent, the present application will be further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, but not to limit the present application. The present application can be implemented without some of these specific details by those skilled in the art. The description of the embodiments below is only to provide a better understanding of the present application by showing examples of the present application. It should be noted that the acquisition, storage, use, processing, etc. of information and data in the embodiments of the present application are authorized by the user or relevant institution and comply with relevant provisions of national laws and regulations.

[0032] With the development of clean energy technologies such as wind power generation technology and photovoltaic power generation technology, the proportion of clean energy devices such as wind turbines and photovoltaic devices in the power system is gradually increasing, making the power system including clean energy devices and the grid have the trend of reduced inertia and weakened strength. In order to cope with power demand and environmental pressure, a network-constructing control strategy can be used to provide damping and inertia for the power system by using network-constructing devices, which can quickly respond when the grid frequency changes and support the stability of the power system. However, due to the differences in the structure of the power system, the grid strength in different regions of the power system is different, and the network-constructing control of the network-constructing device uses a fixed damping coefficient to simulate the damping characteristics, making the active power response characteristics of the network-constructing device under different grid strengths inconsistent and unpredictable, affecting the network-constructing performance of the power system. The active power response characteristics of the network-constructing device under different grid strengths when the grid frequency changes are different, and the support characteristics of the grid are inconsistent, thereby making the power system unstable and reducing the safety and reliability of the power system.

[0033] The present application provides a control method, apparatus, controller, equipment, and medium for a meshing device, which can obtain a damping coefficient under different grid strengths based on the second-order system characteristics of the active power synchronization loop, and obtain the internal potential phase of the meshing device based on the obtained damping coefficient and other control parameters of the active power synchronization loop. The internal potential amplitude of the meshing device is obtained based on the control parameters of the reactive power loop. Thus, a modulation signal for controlling the grid-side converter of the meshing device is generated based on the internal potential phase and internal potential amplitude of the meshing device to control the grid-side converter. The damping coefficient is set according to the grid strength, so that the active power response characteristics of the meshing device under different grid strengths are consistent or tend to be consistent, thereby improving the performance of the active control of the meshing device and eliminating the risk of instability caused by the inconsistent active power response characteristics of the meshing device under different grid strengths, thereby improving the safety and reliability of the power system.

[0034] For ease of understanding, here is a brief introduction to networking devices. Figure 1 This is a schematic diagram of an example of a network-forming device provided in an embodiment of the present application. Figure 1 As shown, the grid-type device in the embodiment of the present application may include a simulated virtual energy source 11 and a grid-side converter 12. The energy source 11 can be electrically connected to the grid-side converter 12 via a DC bus, and the grid-side converter 12 is connected to the power grid 21. The energy source 11 may include but is not limited to energy storage batteries, wind turbines, photovoltaic equipment, etc. The grid-side converter 12 includes a plurality of switching devices. For example, the grid-side converter may include a plurality of insulated-gate bipolar transistors (IGBTs) or other types of switching devices. The current conversion function of the grid-side converter 12 is achieved by coordinating the conduction and shutdown of a plurality of switching devices. Figure 1 The inductance Lf in represents the inductance of the grid-side converter, PCC is the grid connection point between the meshing device and the grid 21, and the impedance Zg represents the line impedance of the line between the meshing device and the grid 21. In the embodiment of the present application, when the meshing device is offline, i.e., when the meshing device is shut down and not in operation, the grid-side converter 12 can be controlled by active power synchronization loop control combined with reactive power loop control, so that the active power response characteristics of the meshing device under different grid strengths are consistent or tend to be consistent.

[0035] The control method, device, controller, equipment and medium of the networking device provided in this application are described below.

[0036] In a first aspect, the present application provides a control method for a networking device, which is applied to the networking device. The control method for the networking device can be executed by a control device, a controller, etc. of the networking device, and is not limited here. Figure 2This is a flow chart of a control method for a networking device provided in one embodiment of the present application, such as Figure 2 As shown, the control method of the networking device may include steps S301 to S304.

[0037] In step S301 , based on the impedance between the grid-side converter and the grid, a preset inertia time constant and a preset angular velocity parameter, and using the second-order system characteristics of the active power synchronization loop, a damping coefficient of the active power synchronization loop is obtained.

[0038] In embodiments of the present application, grid strength can be represented by a short-circuit ratio (SCR). The short-circuit ratio can be the ratio of the three-phase short-circuit capacity of the access busbar electrically connecting the grid-side converter to the grid to the capacity of the grid-connecting device. The three-phase short-circuit capacity can be the short-circuit capacity provided by the energy source simulated by the grid-connecting device. The inertia time constant can describe the ability of the grid-connecting device to release kinetic energy to resist grid frequency changes in the event of power imbalance. In embodiments of the present application, the inertia time constant is pre-set based on the scenario, requirements, etc. Angular velocity parameters can include certain angular velocity-related parameters given during the control process of the grid-connecting device. In some examples, the angular velocity parameters can include the active power synchronization loop cutoff angular velocity and the rated angular velocity of the grid. The active power synchronization loop cutoff angular velocity and the rated angular velocity of the grid can be set based on the scenario, requirements, experience, etc. For example, the rated angular velocity of the grid can also be referred to as the rated angular velocity of the grid voltage. The rated angular velocity of the grid can be 314 rad / s, i.e., 314 radians / second, but is not limited thereto.

[0039] Grid-type equipment uses an active power synchronization loop to simulate the inertia and damping characteristics of synchronous generators, and calculates the internal potential phase of the generator set. The closed-loop transfer function of the active power synchronization loop can be expressed as the ratio of the change in the measured active power of the grid-side converter to the change in the reference active power of the grid-side converter, as shown in the following equation (1):

[0040]

[0041] in, is the change of the measured active power of the grid-side converter; is the change of reference active power of the grid-side converter; ω N is the rated angular velocity of the grid; K x is the inverse of the impedance between the grid-side converter and the grid; T J is the inertia time constant; D is the damping coefficient of the active power synchronization loop. From the above formula (1), it can be obtained that the closed-loop transfer function of the active power synchronization loop is a typical second-order system transfer function. Correspondingly, the active power synchronization loop has second-order system characteristics.

[0042] The second-order system characteristic is related to impedance, inertial time constant, angular velocity parameter and damping coefficient, and the second-order system characteristic of the active power synchronization loop is related to impedance between the grid-side converter and the power grid, inertial time constant, angular velocity parameter and damping coefficient of the active power synchronization loop, and the damping coefficient of the active power synchronization loop can be obtained according to the known impedance between the grid-side converter and the power grid, inertial time constant and angular velocity parameter through the relationship between the impedance between the grid-side converter and the power grid, inertial time constant, angular velocity parameter and damping coefficient of the active power synchronization loop.

[0043] In step S302, the active power synchronization operation is performed according to the damping coefficient, inertial time constant and control parameter of the active power synchronization loop, and the internal electromotive force phase of the grid-connected device is obtained.

[0044] The control parameter of the active power synchronization loop is used to assist in the control operation of the active power synchronization loop. In some examples, the control parameter of the active power synchronization loop can include but is not limited to the measured active power of the grid-side converter, the reference active power of the grid-side converter, the internal electromotive force angular velocity and the rated angular velocity of the power grid. The measured active power of the grid-side converter can be the measured active power of the output of the grid-side converter. The reference active power of the grid-side converter can be the active power of the grid-side converter issued by the controller of the grid-connected device. The internal electromotive force angular velocity is the internal electromotive force angular velocity of the grid-connected device, and further, the internal electromotive force angular velocity can be the internal electromotive force angular velocity obtained by the grid-connected device through the active power synchronization loop. The active power synchronization loop controls by using the virtual synchronous control technology, so that the grid-side converter has the inertia, damping and other characteristics of the synchronous generator. In the case that the grid-side converter has the inertia, damping and other characteristics of the synchronous generator, the active power synchronization operation is performed according to the damping coefficient, inertial time constant, control parameter of the active power synchronization loop and the like, and the internal electromotive force phase of the grid-connected device is obtained. The active power synchronization operation can include difference operation, division operation, integration operation, summation operation and the like. The damping coefficient, inertial time constant and control parameter of the active power synchronization loop can be subjected to the active power synchronization operation such as difference operation, division operation, integration operation, summation operation and the like, and the internal electromotive force phase is obtained through conversion.

[0045] In step S303, the reactive power closed-loop control operation is performed according to the control parameter of the reactive power loop, and the internal electromotive force amplitude of the grid-connected device is obtained.

[0046] The control parameter of the reactive power loop is used to assist in the reactive power closed-loop control operation. In some examples, the control parameter of the reactive power loop can include, but is not limited to, the measured reactive power of the grid-side converter, the reference reactive power of the grid-side converter, and the rated voltage of the grid-connected device. The measured reactive power of the grid-side converter can specifically be the measured reactive power output by the grid-side converter. The reference reactive power of the grid-side converter can specifically be the reactive power issued by the controller to the grid-side converter. The reactive power closed-loop control operation can include difference operation, proportional operation, integral operation, differential operation, etc. The control parameter of the reactive power loop can be subjected to the reactive power closed-loop control operation such as difference operation, proportional operation, integral operation, differential operation, etc., to convert the internal electromotive force amplitude. The internal electromotive force amplitude can also be referred to as the internal electromotive force voltage.

[0047] In step S304, the PWM signal generated based on the internal electromotive force phase and the internal electromotive force amplitude is used to control the operation of the grid-side converter.

[0048] The internal electromotive force phase and the internal electromotive force amplitude can be modulated to generate a pulse width modulation (PWM) signal. The PWM signal can be transmitted to the grid-side converter, and the PWM signal is used to control the conduction and turn-off of the switching device in the grid-side converter, thereby achieving control of the grid-side converter.

[0049] In the embodiments of the present application, the damping coefficient of the active power synchronization loop can be obtained based on the impedance of the grid-side converter to the power grid, the inertia time constant, and the angular velocity parameter, which matches the impedance of the grid-side converter to the power grid. According to the damping coefficient, the inertia time constant, and the control parameter of the active power synchronization loop, the internal electromotive force phase of the grid-connected device is obtained. According to the control parameter of the reactive power loop, the internal electromotive force amplitude of the grid-connected device is obtained. For different impedances of the grid-side converter to the power grid, different damping coefficients of the active power synchronization loop are obtained, which affect the internal electromotive force phase through the damping coefficient, thereby controlling the grid-side converter by the PWM signal generated based on the internal electromotive force phase and the internal electromotive force amplitude, realizing the predictability of the active power response characteristics of the grid-connected device under different grid intensities, making the active power response characteristics of the grid-connected device under different grid intensities consistent or tend to be consistent, reducing or even avoiding the instability risk of the power system, and improving the safety and reliability of the power system.

[0050] In order to reflect the effect of the control method of the grid-connected device in the embodiments of the present application, the active power obtained by the control method using a fixed damping coefficient and the active power obtained by the control method of the grid-connected device in the embodiments of the present application are monitored under the same test conditions, and the difference in active power response characteristics of the two control methods is obtained. Figure 3 An example of the active power response of the grid-connected device under different SCRs obtained by the control method using a fixed damping coefficient is shown in the schematic diagram.Figure 4 This is a schematic diagram of an example of the active power response of the networking equipment obtained by the control method of the damping coefficient self-tuning in the embodiment of the present application. The test condition is that the active power of the networking equipment steps from 0kW to 3000kW. Figure 3 and Figure 4 In the figure, the horizontal axis represents time, and the vertical axis represents active power (kW). The purple, yellow, red, and blue curves correspond to scenarios with a short-circuit ratio of 20, 10, 5, and 2, respectively. The active power response characteristics can be reflected by the active power response time. Figure 3 The active power response time required for the active power values ​​of the curves corresponding to different short-circuit ratios to change and reach stability is inconsistent, and when the grid strength is different (i.e., different short-circuit ratios), the active power response time of the grid-forming equipment also varies greatly. The lower the grid strength, the longer the active power response time required for the grid-forming equipment to reach steady state. Figure 4 The active power response time required for the active power values ​​of the curves corresponding to different short-circuit ratios to change and reach stability is relatively small and tends to be consistent. In summary, the control method of the meshing device provided in the embodiment of the present application can improve the consistency of the active power response characteristics of the meshing device under different short-circuit ratios, that is, different grid strengths, making the power system including the meshing device safer and more stable.

[0051] In some embodiments, a pre-established damping correspondence table may be used to obtain a damping coefficient, thereby implementing active power synchronization calculation according to the damping coefficient. Figure 5 This is a flow chart of a method for controlling a networking device provided in another embodiment of the present application. Figure 5 and Figure 2 The difference is that Figure 2 Step S301 in the above example can be specifically broken down into Figure 5 Steps S3011 to S3013 in Figure 2 Step S302 in the above example can be specifically broken down into Figure 5 Steps S3021 to S3024 in Figure 2 Step S303 in the above example can be specifically broken down into Figure 5 Steps S3031 and S3032 in .

[0052] In step S3011, target intermediate parameters are obtained according to the impedance between the grid-side converter and the grid, the inertia time constant, the angular velocity parameters, and the second-order system characteristics.

[0053] The target intermediate parameter is an intermediate parameter calculated according to an impedance between the grid-side converter and the power grid, an inertia time constant, and an angular velocity parameter. Under the condition of a second-order system characteristic, the target intermediate parameter is negatively correlated with an inverse of the impedance between the grid-side converter and the power grid, and the target intermediate parameter is positively correlated with the inertia time constant. In some examples, the angular velocity parameter can include an active power synchronization loop cutoff angular velocity and a rated angular velocity of the power grid, the active power synchronization loop cutoff angular velocity is positively correlated with the target intermediate parameter, and the rated angular velocity of the power grid is negatively correlated with the target intermediate parameter. For example, the target intermediate parameter can be calculated according to the following formula (2):

[0054]

[0055] wherein K α is the target intermediate parameter; ω b is the active power synchronization loop cutoff angular velocity; T J is the inertia time constant; ω N is the rated angular velocity of the power grid; and K x is an inverse of the impedance between the grid-side converter and the power grid.

[0056] In step S3012, a target damping ratio corresponding to the target intermediate parameter in the pre-established damping corresponding relationship table is determined.

[0057] The intermediate parameter has a corresponding relationship with the damping ratio, and according to the second-order system characteristic, the damping ratio also has a correlation with a damping coefficient. A damping corresponding relationship table can be pre-established, and the damping corresponding relationship table can represent the corresponding relationship between the intermediate parameter and the damping ratio. The damping corresponding relationship table can include a corresponding relationship between the damping ratio and a value range of the intermediate parameter. For example, the damping corresponding relationship table can be represented by the following formula (3):

[0058]

[0059] wherein ξ is the damping ratio; ξ1, ξ2, …, ξ n are damping ratios with different values; K β1 ≤ K α < K β2 , K β2 ≤ K α < K β3 , …, K β(n-1) ≤ K α < K βn are different value ranges of the intermediate parameter. The damping corresponding relationship table can also be represented in the form of a table, which is not specifically illustrated here.

[0060] In some examples, before executing step S3012, a damping correspondence table can be established in advance. Specifically, a plurality of different damping ratios can be obtained, and based on the second-order system characteristics and a plurality of different damping ratios, the value ranges of the intermediate parameters corresponding to the plurality of different damping ratios can be calculated; based on the plurality of different damping ratios and the value ranges of the corresponding intermediate parameters, a damping correspondence table between the intermediate parameters and the damping ratios can be established. The second-order system characteristics include the relationship between the intermediate parameters and the damping ratios. When the correspondence between the intermediate parameters and the damping ratios is known, the corresponding intermediate parameters can be calculated using the known damping ratios. In order to form the value ranges of the plurality of intermediate parameters, a plurality of different damping ratios can be selected first. For each damping ratio, the intermediate parameters corresponding to the damping ratio can be calculated using the second-order system characteristics. The intermediate parameters corresponding to the plurality of damping ratios are summarized to obtain the correspondence between the damping ratio and the value range of the intermediate parameters. For example, the relationship between the damping ratio and the intermediate parameter in the second-order system characteristics can be shown as follows (4):

[0061]

[0062] Among them, K β is the intermediate parameter; ξ is the damping ratio. If ξ1 in the above formula (3) is substituted into the above formula (4), the K β The value range should be [K β1 ,K β2 ), similarly, substitute ξ2 in the above formula (3) into the above formula (4) to calculate K β The value range should be [K β2 ,K β3 By establishing a correspondence between multiple damping ratios and the value ranges of the intermediate parameters calculated based on the multiple damping ratios and the second-order system characteristics, a damping correspondence table between the intermediate parameters and the damping ratios can be established.

[0063] In some examples, the value range of the intermediate parameter within which the target intermediate parameter falls can be determined in the damping correspondence table between the intermediate parameter and the damping ratio; in the damping correspondence table, the damping ratio corresponding to the value range within which the intermediate parameter falls is determined as the target damping ratio. For example, as shown in the above formula (4), after obtaining the target intermediate parameter K α After that, if K α Fall into [K β1 ,K β2 ), in the damping correspondence table of the intermediate parameters and the damping ratio, the damping ratio corresponding to the parameter range is ξ1, then the target damping ratio can be determined to be ξ1; if K α Fall into [K β2 ,K β3In the intermediate parameter-damping ratio damping correspondence table, if the damping ratio corresponding to the parameter range of the intermediate parameter is ξ 2, the target damping ratio is determined as ξ 2. It is more convenient and fast to use the intermediate parameter-damping ratio damping correspondence table to find the target damping ratio corresponding to the target intermediate parameter.

[0064] In some other examples, the corresponding damping ratio can also be calculated according to the relationship between the damping ratio and the intermediate parameter in the second-order system characteristic and the target intermediate parameter, and the corresponding damping ratio is determined as the target damping ratio each time the target intermediate parameter is obtained. The relationship between the damping ratio and the intermediate parameter in the second-order system characteristic can be referred to the related description in the above embodiments, which will not be described here.

[0065] In step S3013, the damping coefficient is obtained according to the target damping ratio, the angular velocity parameter, the inertia time constant, the impedance of the grid-side converter to the power grid, and the second-order system characteristic.

[0066] The second-order system characteristic includes a functional relationship between the damping ratio, the angular velocity parameter, the inertia time constant, the impedance of the grid-side converter to the power grid, and the damping coefficient. In the case where the functional relationship and the damping ratio, the angular velocity parameter, the inertia time constant, and the impedance of the grid-side converter to the power grid are known, the corresponding damping coefficient can be calculated. In the second-order system characteristic, the damping ratio, the angular velocity parameter, and the inertia time constant are positively correlated with the damping coefficient, and the impedance of the grid-side converter to the power grid is negatively correlated with the damping coefficient. For example, the damping coefficient can be calculated according to the following formula (5):

[0067]

[0068] wherein D is the damping coefficient; ξ is the target damping ratio; ω N is the rated angular velocity of the power grid; K x is the inverse of the impedance of the grid-side converter to the power grid; T J is the inertia time constant.

[0069] In step S3021, the torque increment of the grid-forming device is obtained according to the difference between the reference active power and the measured active power, and the internal electromotive force angular velocity.

[0070] The difference between the reference active power and the measured active power can represent the difference between the actual output active power of the grid-side converter and the reference active power. The difference between the active power can be divided by the internal electromotive force angular velocity to convert the difference between the active power into the torque increment, and the torque increment is used for the next calculation.

[0071] In step S3022, the angular velocity increment is obtained according to the torque increment, the inertia time constant, and the damping coefficient.

[0072] A mathematical model describing the inertia and damping characteristics can be obtained according to the inertia time constant and the damping coefficient. The torque increment is taken as the input of the mathematical model having the inertia and damping characteristics, and the output angular velocity increment can be obtained.

[0073] In step S3023, the sum of the rated angular velocity and the angular velocity increment is integrated to obtain the internal electromotive force phase.

[0074] For example, Figure 6 A schematic diagram of an example of the active power loop synchronization control provided by the embodiment of the present application is shown in FIG. 3, which will be described below. Figure 6 As shown in FIG. 3, the difference between the reference active power P and the measured active power P is divided by the internal electromotive force angular velocity ω * to obtain an operation result, i.e., the torque increment. The operation result is taken as the input of the mathematical model , and the output of the mathematical model, i.e., the angular velocity increment Δω, is obtained, where T J is the inertia time constant, D is the damping coefficient, and s is the Laplace operator. The angular velocity increment Δω is added to the rated angular velocity ω N of the power grid, and the sum is integrated to obtain the internal electromotive force phase θ, Figure 6 , where is the integral operation.

[0075] In step S3031, the difference between the reference reactive power and the measured reactive power is subjected to a closed-loop control operation to obtain the voltage increment of the grid-forming device.

[0076] The closed-loop control operation includes at least one of proportional (i.e., Proportional) operation, integral (i.e., Integral) operation, and differential (i.e., Derivative) operation, for example, the closed-loop control operation can be implemented as proportional operation, integral operation, proportional-integral operation, or proportional-integral-differential operation. The difference between the reference reactive power and the measured reactive power is taken as the input of the closed-loop control operation, and the output of the closed-loop control operation is the voltage increment of the grid-forming device.

[0077] In step S3032, the sum of the voltage increment and the rated voltage is determined as the internal electromotive force amplitude.

[0078] For example, Figure 7 A schematic diagram of an example of the reactive power loop control provided by the embodiment of the present application is shown in FIG. 4, which will be described below. Figure 7 As shown in FIG. 4, the difference between the reference reactive power Q ref and the measured reactive power Q meas is taken as the input of the closed-loop control operation, and the output of the closed-loop control operation is the voltage increment ΔU. The sum of the voltage increment and the rated voltage U * of the grid-forming device is determined as the internal electromotive force amplitude U.

[0079] Figure 8 A schematic diagram of an example of the networked device control provided by an embodiment of the present application is shown in Figure 8 The structure of the networked device in Figure 1 is not described again here. As shown in Figure 8 , the internal potential phase θ and the internal potential amplitude U are signal-modulated to obtain a PWM signal, which can be input to the grid-side converter 12 to control the coordination of the turn-on and turn-off of the switching devices in the grid-side converter 12, so as to control the grid-side converter to make the active power response characteristics of the networked device under different grid strengths (i.e. different short-circuit ratios) consistent or tend to be consistent. The consistency or tendency to be consistent of the active power response characteristics of the networked device here can mean that the gap between the active power response characteristics of the networked device under different grid strengths is within a preset standard range, which can be set according to the scene, demand, experience, etc. and is not limited here.

[0080] The second aspect of the present application provides a networked device control device applied to a networked device, the networked device comprising a grid-side converter configured to be connected to a power grid. Figure 9 The structure of the networked device control device provided by an embodiment of the present application is shown in Figure 9 As shown in the figure, the networked device control device 400 can comprise a damping coefficient setting module 401, a phase determination module 402, an amplitude determination module 403 and a control module 404.

[0081] The damping coefficient setting module 401 can be used to obtain the damping coefficient of the active power synchronization loop based on the impedance between the grid-side converter and the power grid, the preset inertia time constant and the preset angular velocity parameter, using the second-order system characteristics of the active power synchronization loop.

[0082] The phase determination module 402 can be used to perform active power synchronization operation according to the damping coefficient, the inertia time constant and the control parameters of the active power synchronization loop to obtain the internal potential phase of the networked device.

[0083] The amplitude determination module 403 can be used to perform reactive power closed-loop control operation according to the control parameters of the reactive power loop to obtain the internal potential amplitude of the networked device.

[0084] The control module 404 can be used to control the operation of the grid-side converter using the PWM signal generated based on the internal potential phase and the internal potential amplitude.

[0085] In some embodiments, the damping coefficient setting module 401 can be specifically configured to: obtain a target intermediate parameter according to an impedance between the grid-side converter and the power grid, an inertia time constant, an angular velocity parameter, and a second-order system characteristic; determine a target damping ratio corresponding to the target intermediate parameter in a damping corresponding relationship table in the damping corresponding relationship table, the damping corresponding relationship table including a corresponding relationship between damping ratios and a value range of intermediate parameters; and obtain the damping coefficient according to the target damping ratio, the angular velocity parameter, the inertia time constant, the impedance between the grid-side converter and the power grid, and the second-order system characteristic.

[0086] In some examples, the control device 400 of the grid-forming device can further include a relationship table generation module. The relationship table generation module can be configured to: obtain a plurality of different damping ratios, and calculate a value range of an intermediate parameter corresponding to each of the plurality of different damping ratios according to the second-order system characteristic and the plurality of different damping ratios; and establish a damping corresponding relationship table according to the plurality of different damping ratios and the value range of the corresponding intermediate parameter.

[0087] In some examples, the damping coefficient setting module 401 can be specifically configured to: determine a value range of an intermediate parameter into which the target intermediate parameter falls in the damping corresponding relationship table; and determine the corresponding damping ratio of the value range of the intermediate parameter into which the intermediate parameter falls in the damping corresponding relationship table as the target damping ratio.

[0088] In some examples, the angular velocity parameter includes an active power synchronization ring cutoff angular velocity and a rated angular velocity of the power grid.

[0089] In some embodiments, the control parameters of the active power synchronization ring include a measured active power of the grid-side converter, a reference active power of the grid-side converter, an internal electromotive force angular velocity, and a rated angular velocity of the power grid. The phase determination module 402 can be specifically configured to: obtain a torque increment of the grid-forming device according to a difference between the reference active power and the measured active power, and the internal electromotive force angular velocity; obtain an angular velocity increment according to the torque increment, the inertia time constant, and the damping coefficient; and integrate an addition of the rated angular velocity and the angular velocity increment to obtain an internal electromotive force phase.

[0090] In some embodiments, the control parameters of the reactive power ring include a measured reactive power of the grid-side converter, a reference reactive power of the grid-side converter, and a rated voltage of the grid-forming device. The amplitude determination module 403 can be specifically configured to: perform a closed-loop control operation on a difference between the reference reactive power and the measured reactive power to obtain a voltage increment of the grid-forming device, the closed-loop control operation including at least one of proportional operation, integral operation, and differential operation; and determine an addition of the voltage increment and the rated voltage as an internal electromotive force amplitude.

[0091] It should be noted that the control device 400 of the networked device is a device corresponding to the control method of the networked device described above, and all implementation manners in the method embodiments are applicable to the device embodiments, and the same technical effects can be achieved, and details are not described herein.

[0092] The third aspect of the present application further provides a controller of a networked device. Figure 10 The structural schematic diagram of the controller of the networked device provided by an embodiment of the present application is shown in Figure 10 The controller 500 of the networked device includes a memory 501, a processor 502, and a computer program stored in the memory 501 and executable on the processor 502.

[0093] In some examples, the processor 502 can include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement one or more embodiments of the present application.

[0094] The memory 501 can include a read-only memory (ROM), a random access memory (RAM), a magnetic disk storage medium device, an optical storage medium device, a flash memory device, an electrical, optical, or other physical / tangible memory storage device. Therefore, generally, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions and when the software is executed (e.g., by one or more processors), it is operable to perform operations described with reference to the control method of the networked device according to embodiments of the present application.

[0095] The processor 502 runs the computer program corresponding to the executable program code stored in the memory 501 by reading the executable program code, to implement the control method of the networked device in the above embodiments.

[0096] In some examples, the controller 500 of the networked device can further include a communication interface 503 and a bus 504. As shown in Figure 10 The memory 501, the processor 502, and the communication interface 503 are connected through the bus 504 and complete communication with each other.

[0097] The communication interface 503 is mainly used to realize the communication between various modules, devices, units, and / or equipment in the embodiments of the present application. Input devices and / or output devices can also be accessed through the communication interface 503.

[0098] The bus 504 includes hardware, software, or both that couples the components of the controller 500 of the networking device to each other. By way of example and not limitation, the bus 504 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-E) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses, or a combination of two or more of the above. Where appropriate, the bus 504 may include one or more buses. Although embodiments herein describe and illustrate a particular bus, this application contemplates any suitable bus or interconnect.

[0099] A fourth aspect of the present application provides a networking device, Figure 11 This is a schematic diagram of the structure of a networking device provided in one embodiment of the present application. Figure 11 and Figure 1 The difference is that Figure 11 The illustrated meshing device also includes a meshing device controller 13. The meshing device controller 13 is connected to the grid-side converter and can execute the control method for the meshing device described in the first embodiment. For details, refer to the relevant content in the above embodiments. The same technical effects can be achieved and, to avoid repetition, are not described here. In some examples, the meshing device may include, but is not limited to, wind turbines, photovoltaic equipment, and the like.

[0100] The fifth aspect of the present application provides a computer readable storage medium, which stores computer program instructions. The computer program instructions are executed by a processor to implement the control method of the network construction device in the above embodiments, and achieve the same technical effects. To avoid repetition, details are not described herein. The computer readable storage medium can include a non-transitory computer readable storage medium, such as a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and the like, which is not limited herein.

[0101] The embodiments of the present application provide a computer program product, which includes a computer program. The computer program is executed by a processor to implement the control method of the network construction device in the above embodiments, and achieve the same technical effects. To avoid repetition, details are not described herein.

[0102] It should be noted that each embodiment in the present specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other. Each embodiment focuses on the difference from other embodiments. For the device embodiment, the controller embodiment, the network construction device embodiment, the computer readable storage medium embodiment, and the computer program product embodiment, the related parts can be referred to the description of the method embodiment. The present application is not limited to the specific steps and structures described above and shown in the drawings. Those skilled in the art can make various changes, modifications and additions, or change the order of the steps, after understanding the spirit of the present application. Moreover, for the sake of brevity, detailed description of known methods and techniques is omitted herein.

[0103] The above describes the aspects of the present application with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present application. It should be understood that each block in the flowcharts and / or block diagrams, and the combination of the blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus, to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus enable the implementation of the functions / actions specified in one or more blocks of the flowcharts and / or block diagrams. The processor can be, but is not limited to, a general purpose processor, a special purpose processor, a special application processor or a field programmable logic circuit. It should also be understood that each block in the block diagrams and / or flowcharts, and the combination of the blocks in the block diagrams and / or flowcharts, can also be implemented by special hardware to perform the specified functions or actions, or can be implemented by a combination of special hardware and computer instructions.

[0104] It should be understood by those skilled in the art that the above embodiments are exemplary but not limiting. Different technical features appearing in different embodiments can be combined to achieve beneficial effects. Other changed embodiments of the disclosed embodiments can be understood and implemented by those skilled in the art based on the drawings, the specification and the claims. In the claims, the term "comprising" does not exclude other devices or steps; the numerical term "one" does not exclude a plurality; the terms "first", "second" are used to designate names and not to indicate any particular order. Any reference signs in the claims should not be understood as limiting the scope of protection. The functions of multiple parts appearing in the claims can be implemented by a single hardware or software module. The fact that certain technical features appear in different dependent claims does not mean that these technical features cannot be combined to achieve beneficial effects.

Claims

1. A method for controlling a networking device, characterized in that: The grid-type device includes a grid-side converter, and the grid-side converter is configured to be connected to a power grid; the method includes: When the grid-forming device is in an offline state, a damping coefficient of the active power synchronization ring is obtained based on the impedance between the grid-side converter and the grid, a preset inertia time constant of the grid-forming device, and a preset angular velocity parameter of the grid-forming device, using a second-order system characteristic of the active power synchronization ring, wherein the angular velocity parameter includes a cutoff angular velocity of the active power synchronization ring and a rated angular velocity of the grid; Performing active power synchronization calculation according to the damping coefficient, the inertia time constant, and the control parameters of the active power synchronization loop to obtain the internal potential phase of the meshing device; Performing a reactive power closed-loop control operation according to the control parameters of the reactive power loop to obtain the internal potential amplitude of the network-forming device; The operation of the grid-side converter is controlled by using a PWM signal generated based on the internal potential phase and the internal potential amplitude, so that the active power response characteristics of the grid-type device under different grid strengths are consistent or tend to be consistent.

2. The method according to claim 1, characterized in that The method of obtaining the damping coefficient of the active power synchronization ring based on the impedance between the grid-side converter and the grid, a preset inertia time constant, and a preset angular velocity parameter and utilizing the second-order system characteristics of the active power synchronization ring includes: Obtaining a target intermediate parameter according to the impedance between the grid-side converter and the grid, the inertia time constant, the angular velocity parameter, and the second-order system characteristics; Determining a target damping ratio corresponding to the target intermediate parameter in a pre-established damping correspondence table, wherein the damping correspondence table includes a correspondence between the damping ratio and the value range of the intermediate parameter; The damping coefficient is obtained according to the target damping ratio, the angular velocity parameter, the inertia time constant, the impedance between the grid-side converter and the grid, and the second-order system characteristics.

3. The method according to claim 2, characterized in that In the pre-established damping correspondence table, before determining the target damping ratio corresponding to the target intermediate parameter in the damping correspondence table, the method further includes: Acquire a plurality of different damping ratios, and calculate, based on the second-order system characteristics and the plurality of different damping ratios, obtain value ranges of intermediate parameters corresponding to the plurality of different damping ratios; The damping correspondence table is established according to the multiple different damping ratios and the value ranges of the corresponding intermediate parameters.

4. The method according to claim 2, characterized in that The step of determining the target damping ratio corresponding to the target intermediate parameter in the pre-established damping correspondence table includes: In the damping correspondence table, determining a value range of the intermediate parameter within which the target intermediate parameter falls; The damping ratio corresponding to the value range of the intermediate parameter within which the intermediate parameter falls in the damping correspondence table is determined as the target damping ratio.

5. The method according to claim 1, wherein The control parameters of the active power synchronization loop include the measured active power of the grid-side converter, the reference active power of the grid-side converter, the internal potential angular velocity and the rated angular velocity of the grid; The performing active power synchronization calculation according to the damping coefficient, the inertia time constant, and the control parameters of the active power synchronization loop to obtain the internal potential phase of the meshing device includes: Obtaining a torque increment of the network-forming device according to a difference between the reference active power and the measured active power, and the internal potential angular velocity; Obtaining an angular velocity increment according to the torque increment, the inertia time constant, and the damping coefficient; The internal potential phase is obtained by performing an integration operation on the sum of the rated angular velocity and the angular velocity increment.

6. The method according to claim 1, characterized in that The control parameters of the reactive power loop include the measured reactive power of the grid-side converter, the reference reactive power of the grid-side converter and the rated voltage of the grid-type device; The performing of a reactive power closed-loop control operation according to the control parameters of the reactive power loop to obtain the internal potential amplitude of the networked device includes: Performing a closed-loop control operation on the difference between the reference reactive power and the measured reactive power to obtain a voltage increment of the networked device, wherein the closed-loop control operation includes at least one of a proportional operation, an integral operation, and a differential operation; The sum of the voltage increment and the rated voltage is determined as the internal potential amplitude.

7. A control device for a networking device, characterized in that: Applicable to a grid-type device, the grid-type device comprising a grid-side converter, the grid-side converter being configured to be connected to a power grid; The device comprises: a damping coefficient setting module, configured to, when the grid-forming device is in an offline state, obtain a damping coefficient of the active power synchronization loop based on the impedance between the grid-side converter and the grid, a preset inertia time constant of the grid-forming device, and a preset angular velocity parameter of the grid-forming device, and utilizing the second-order system characteristics of the active power synchronization loop, wherein the angular velocity parameter includes a cutoff angular velocity of the active power synchronization loop and a rated angular velocity of the grid; a phase determination module, configured to perform active power synchronization calculation according to the damping coefficient, the inertia time constant, and the control parameters of the active power synchronization loop to obtain the internal potential phase of the meshing device; an amplitude determination module, configured to perform a reactive power closed-loop control operation according to control parameters of the reactive power loop to obtain an internal potential amplitude of the networked device; A control module is used to control the operation of the grid-side converter using a PWM signal generated based on the internal potential phase and the internal potential amplitude, so that the active power response characteristics of the grid-type device under different grid strengths are consistent or tend to be consistent.

8. A controller for a networking device, characterized in that: include: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, the method for controlling a meshed device according to any one of claims 1 to 6 is implemented.

9. A networking device, characterized in that: include: a grid-side converter, wherein an output end of the grid-side converter is configured to be connected to a power grid; The controller of the grid-type device according to claim 8, connected to the grid-side converter.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer program instructions, and when the computer program instructions are executed by a processor, the method for controlling a meshed device according to any one of claims 1 to 6 is implemented.

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