A method and device for grid connection control of new energy power generation

Abstract

This application provides a new energy power generation grid connection control method and control device, relating to the field of grid connection control technology. The new energy power generation grid connection control method is applied to a new energy power generation-energy storage transmission system. The control method includes: acquiring grid frequency information; responding to the grid frequency information, obtaining inertial response data and frequency regulation data; responding to the inertial response data and the frequency regulation data, controlling the new energy power generation-energy storage transmission system to provide inertial response and frequency regulation strategies to the grid, and the new energy power generation-energy storage transmission system couples a preset capacity of energy storage to a DC bus through a preset circuit. The control method enables the new energy power generation-energy storage transmission system to autonomously support the grid, providing real-time and reliable active frequency support to the grid.

Description

Technical Field

[0001] This application relates to the field of grid connection control technology, and more specifically, to a new energy power generation grid connection control method and control device. Background Technology

[0002] Currently, with the increasing urgency of global climate change response and the growing severity of energy shortages and security concerns, the world's energy development has entered a new period of strategic adjustment. Large-scale development and utilization of offshore wind power is a powerful means to address energy shortages and a significant current need.

[0003] Generally, when using AC transmission, the charging effect of long-distance submarine cables will significantly increase the transmission cost of offshore wind power. Therefore, flexible DC transmission technology, which has fast power decoupling control characteristics, island grid access capability, and does not require reactive power compensation equipment, is an important technical means for large-scale offshore wind power grid integration in the future.

[0004] Unlike synchronous generators, which have voltage source characteristics, conventional wind power-flexible DC systems currently have current source characteristics. They have no inertia to the grid and cannot participate in frequency regulation. This makes it impossible for offshore wind-flexible DC grid-connected systems to support the grid autonomously like synchronous generators and to provide real-time and reliable active frequency support to the grid. Summary of the Invention

[0005] The purpose of this application is to provide a new energy power generation grid connection control method, control device, electronic device and computer-readable storage medium, which can realize the autonomous support of the power grid by the new energy power generation-energy storage transmission system and provide real-time and reliable active frequency support for the power grid.

[0006] In a first aspect, this application provides a new energy power generation grid connection control method, applied to a new energy power generation-energy storage transmission system, the control method comprising:

[0007] Obtain power grid frequency information;

[0008] In response to the power grid frequency information, inertial response data and frequency modulation data are obtained;

[0009] In response to the inertia response data and the frequency regulation data, the new energy power generation-storage transmission system is controlled to provide inertia response and frequency regulation strategies to the power grid, and the new energy power generation-storage transmission system couples a preset capacity of energy storage to the DC bus through a preset circuit.

[0010] In the above implementation process, in response to the grid frequency response requirements of the new energy power generation-storage transmission system, the system couples a preset capacity of energy storage to the DC bus through a preset circuit. Based on inertia response data and frequency regulation data, the new energy power generation-storage transmission system provides inertia response and frequency regulation strategies to the grid. With coordinated energy storage control, the new energy power generation-storage transmission system, from the perspective of the onshore grid connection point, resembles a large synchronous generator. It can autonomously release the inertia of the wind turbine and autonomously mobilize the energy storage to participate in the primary frequency regulation of the grid, exhibiting voltage source characteristics. This enables the new energy power generation-storage transmission system to autonomously support the grid and provide real-time and reliable active frequency support to the grid.

[0011] Furthermore, the control method further includes:

[0012] In response to the grid frequency information, the receiving-end converter of the new energy power generation-storage transmission system is controlled by a self-synchronizing voltage source, and the grid frequency information and the DC bus voltage satisfy a preset relationship.

[0013] In the above implementation process, the receiving-end converter adopts self-synchronizing voltage source control, and the grid frequency information and DC bus voltage satisfy a preset relationship, that is, the grid frequency information and DC bus voltage establish a one-to-one correspondence, thereby mapping the grid frequency onto the DC voltage to provide inertial response and primary frequency regulation strategy to the grid.

[0014] Furthermore, the control method further includes:

[0015] The sending-end converter of the new energy power generation-storage transmission system is controlled to obtain the grid frequency information from the DC bus.

[0016] The grid frequency information is transmitted to the wind farm side of the new energy power generation-storage transmission system. The wind turbines on the wind farm side provide inertial response to the grid based on the grid frequency information and the AC frequency information detected by the phase-locked loop.

[0017] In the above implementation process, after the sending-end converter extracts the grid frequency information from the DC bus, it transmits the grid frequency to the wind farm side of the offshore wind farm. The wind turbines of the offshore wind farm detect the AC frequency through a phase-locked loop, thereby providing inertial response to the grid.

[0018] Furthermore, the receiving-end converter of the new energy power generation-storage transmission system is equipped with a module group, which includes multiple sub-modules, and the control method further includes:

[0019] Based on the synchronous generator rotor simulation of the capacitors of multiple sub-modules in the module group at the receiving end converter, the receiving end converter is controlled to achieve phase-locked loop self-synchronization with the power grid.

[0020] In the above implementation process, the receiving-end converter achieves phase-locked loop-free grid self-synchronization by analogy of the capacitor of the sub-module to the rotor of a synchronous generator and simulation, thereby enabling the DC voltage on the DC bus to automatically map the grid frequency changes.

[0021] Furthermore, the control method further includes:

[0022] Obtain the number of sub-modules in the module group;

[0023] In response to the quantity information of the submodules, the grid frequency information is matched to the capacitor energy of the submodules according to the preset DC-side control mode of the receiving-end converter.

[0024] In the above implementation process, the appropriate DC side control method is selected according to the number of sub-modules put into the DC side, so as to automatically map the grid frequency onto the DC bus voltage.

[0025] Furthermore, the preset DC-side control mode includes a coupled control mode and a decoupled control mode. In response to the number of submodules, the grid frequency information is matched to the capacitor energy corresponding to the submodule according to the preset DC-side control mode of the receiving-end converter, including:

[0026] If the quantity information of the sub-module is constant, the grid frequency information is matched to the capacitor energy corresponding to the sub-module according to the coupled control method;

[0027] If the number of sub-modules is not a constant, the grid frequency information is matched to the capacitor energy corresponding to the sub-module according to the decoupling control method.

[0028] In the above implementation process, both coupled and decoupled control can automatically map the grid frequency onto the DC bus voltage. Based on this characteristic, energy storage devices and sending-end converters can obtain grid frequency information by detecting DC voltage. Energy storage devices can respond directly, providing inertia support and primary frequency regulation. The sending-end converter can change the AC frequency of the wind farm to transmit the grid frequency change to each wind turbine in the offshore wind farm, and the wind turbines can provide a fast frequency response to the grid. Ultimately, the self-synchronizing voltage source control of the new energy power generation-energy storage transmission system is realized, providing active frequency support to the grid.

[0029] Furthermore, the control method further includes:

[0030] In response to the DC current and DC voltage on the DC side of the receiving-end converter, the DC bus voltage is controlled according to a preset dual closed-loop control strategy.

[0031] In the above implementation process, the DC bus voltage can be rapidly controlled by the dual closed-loop control of the DC voltage and DC current on the DC side of the receiving-end converter.

[0032] Furthermore, the control method further includes:

[0033] In response to the grid frequency information, the output AC voltage of the receiving-end converter of the new energy power generation-storage transmission system is controlled.

[0034] In the above implementation process, by controlling the output AC voltage of the receiving-end converter, the damping can be increased, thereby shortening the process time for the receiving-end converter to synchronize with the grid frequency and improving stability.

[0035] Furthermore, the preset capacity ranges from 15% to 20%.

[0036] Furthermore, the preset circuit includes multiple sub-modules connected in series; wherein, the sub-module includes a converter unit connected in parallel with the energy storage unit.

[0037] Secondly, this application provides a new energy power generation grid connection control device, applied to a new energy power generation-energy storage and transmission system, the control device comprising:

[0038] The power grid frequency unit is used to acquire power grid frequency information.

[0039] A response unit is used to obtain inertial response data and frequency modulation data in response to the power grid frequency information;

[0040] The control unit is used to respond to the inertia response data and the frequency regulation data, control the new energy power generation-storage transmission system to provide inertia response and frequency regulation strategies to the power grid, and the new energy power generation-storage transmission system couples a preset capacity of energy storage to the DC bus through a preset circuit.

[0041] Furthermore, the control unit is also configured to: respond to the grid frequency information, control the receiving-end converter of the new energy power generation-storage transmission system through self-synchronizing voltage source control, and the grid frequency information and the DC bus voltage satisfy a preset relationship.

[0042] Furthermore, the control unit is also used to: control the sending-end converter of the new energy power generation-storage transmission system to obtain the grid frequency information from the DC bus; transmit the grid frequency information to the wind farm side of the new energy power generation-storage transmission system, and the wind turbines on the wind farm side provide inertial response to the grid based on the grid frequency information and the phase-locked loop detection AC frequency information.

[0043] Furthermore, the receiving-end converter of the new energy power generation-storage transmission system is equipped with a module group, which includes multiple sub-modules. The control unit is also used to: simulate the synchronous generator rotor based on the capacitors of the multiple sub-modules in the module group in the receiving-end converter, and control the receiving-end converter to achieve phase-locked loop self-synchronization with the power grid.

[0044] Furthermore, the control unit is also configured to: acquire the number information of sub-modules in the module group; and, in response to the number information of the sub-modules, match the grid frequency information with the capacitor energy corresponding to the sub-module according to the preset DC-side control mode of the receiving-end converter.

[0045] Furthermore, the preset DC-side control mode includes a coupled control mode and a decoupled control mode. The control unit is also used to: if the number of sub-modules is constant, match the grid frequency information to the capacitor energy corresponding to the sub-module according to the coupled control mode; if the number of sub-modules is not constant, match the grid frequency information to the capacitor energy corresponding to the sub-module according to the decoupled control mode.

[0046] Thirdly, this application provides an electronic device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the steps of the method described in any of the first aspects.

[0047] Fourthly, this application provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the method described in any of the first aspects.

[0048] Fifthly, this application provides a computer program product that, when run on a computer, causes the computer to perform the method described in any of the first aspects.

[0049] Other features and advantages disclosed in this application will be set forth in the following description, or some features and advantages may be inferred from the description or determined without doubt, or may be learned by practicing the above-described technology disclosed in this application.

[0050] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a topology diagram of a new energy power generation-storage transmission system provided in an embodiment of this application;

[0053] Figure 2 A flowchart illustrating the grid connection control method for new energy power generation provided in this application embodiment;

[0054] Figure 3 A schematic diagram of the equivalent circuit of the DC side of the receiving-end MMC under decoupled control provided in the embodiments of this application;

[0055] Figure 4 This is a schematic diagram of DC voltage-DC current dual closed-loop control provided in an embodiment of this application;

[0056] Figure 5 This is a schematic diagram of the topology of a new energy power generation-storage transmission system with self-synchronous voltage source control provided in an embodiment of this application;

[0057] Figure 6 A structural block diagram of the new energy power generation grid connection control device provided in the embodiments of this application;

[0058] Figure 7 This is a structural block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0059] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0060] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0061] With the increasing urgency of global climate change response and the growing severity of energy shortages and energy supply security, the world's energy development has entered a new round of strategic adjustment. In contrast, large-scale development and utilization of offshore wind power is a powerful means to achieve the goal of solving energy shortages and improving energy supply security, and it is also a major need for my country at present.

[0062] Generally, for offshore wind power systems, the charging effect of long-distance submarine cables significantly increases transmission costs when using AC power transmission. Therefore, flexible DC transmission technology, characterized by rapid power decoupling control, islanded grid connection capabilities, and the elimination of reactive power compensation equipment, is a crucial technology for large-scale offshore wind power grid integration in the future. Unlike the voltage source characteristics of synchronous generators, conventional wind-power-flexible DC systems are current source characteristics, lacking grid inertia and unable to participate in frequency regulation. Given that capacity has already reached the GW level, enabling offshore wind-power-flexible DC grid-connected systems to autonomously support the grid like synchronous generators and possess the characteristics of a supporting power source is of great significance. Furthermore, achieving this transformation with low cost and high reliability is particularly important. Through the synergy of flexible DC, energy storage, and wind power, real-time and reliable active frequency support can be provided to the grid.

[0063] For example, for the flexible DC system commonly used in the market, by connecting the high-voltage, high-capacity DC side of the energy storage battery to the grid, it can provide frequency response to the grid. However, it does not involve how the energy storage device measures the grid frequency. Generally, it needs to be done through communication. Moreover, this technology does not involve wind farms. The ability to provide frequency response by relying solely on energy storage is limited, and the cost is higher than that of wind farm inertial response.

[0064] Alternatively, the grid frequency can be transmitted to the wind farm through a flexible DC system, helping the wind farm to sense the grid frequency in real time and provide inertial response. However, this technology does not involve energy storage systems and relies solely on the wind farm to provide inertial response, resulting in weak support for the grid.

[0065] To address the aforementioned technical problems, this application provides a new energy power generation grid connection control method. Targeting the grid frequency response requirements of a new energy power generation-storage transmission system, this method couples a preset capacity of energy storage to a DC bus via a preset circuit. Based on inertia response data and frequency regulation data, it controls the new energy power generation-storage transmission system to provide inertia response and frequency regulation strategies to the grid. This coordinated energy storage control allows the new energy power generation-storage transmission system, viewed from the onshore grid connection point, to resemble a large synchronous generator. It can autonomously release the inertia of wind turbine units and autonomously mobilize energy storage to participate in primary grid frequency regulation, exhibiting voltage source characteristics. This enables the new energy power generation-storage transmission system to autonomously support the grid, providing real-time and reliable active frequency support to the grid.

[0066] For example, this application provides a new energy power generation grid connection control method, which can change the current source characteristics of conventional wind power flexible grid connection systems that rely on grid operation, cannot dampen grid frequency fluctuations, and cannot participate in grid primary frequency regulation.

[0067] The new energy power generation grid connection control method, system, electronic device, and computer-readable storage medium disclosed in this application can be applied in a controller to realize self-synchronizing voltage source control of a new energy power generation-energy storage transmission system. The controller includes a server, which can be a standalone server or a server cluster composed of multiple servers. It can also be a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence sampling point devices.

[0068] For example, the new energy power generation-storage transmission system described in the embodiments of this application can be a new energy power generation system such as wind power, solar power, tidal power, etc. Optionally, the new energy power generation-storage transmission system described below takes the offshore wind-flexible DC-storage transmission system as an example for the purpose of description only, and does not represent a limitation on the application scope of the new energy power generation-storage transmission system.

[0069] According to some embodiments of this application, please refer to Figure 1 , Figure 1 This is a topology diagram of a new energy power generation-storage transmission system provided in an embodiment of this application; the new energy power generation-storage transmission system includes an offshore wind farm 101, an AC submarine cable 102, a sending-end converter 103, a DC submarine cable 104, a receiving-end converter 105, a power grid 106, and an energy storage device 107.

[0070] Among them, the offshore wind farm 101, AC submarine cable 102, sending-end converter 103, DC submarine cable 104, receiving-end converter 105, and power grid 106 are connected in sequence; generally, power grid 106 refers to the onshore AC power grid.

[0071] Energy storage device 107 is installed on the DC side of receiving-end converter 105, such as Figure 1 As shown, the capacity of the energy storage device 107 is configured according to the preset capacity of energy storage; in some embodiments, 15% to 20% of the rated capacity of the system can be directly coupled to the high voltage DC bus (i.e., DC submarine cable 104) of the new energy power generation-energy storage transmission system through a preset circuit, thereby forming a high voltage DC direct-connected energy storage.

[0072] For example, the preset circuit described in the embodiments of this application can be a power network wiring circuit, such as a radial trunk type, chain type, double-circuit radial type, trunk type, chain ring type, etc. power network wiring circuit, which is limited here.

[0073] For example, the preset circuit includes multiple sub-modules connected in series; wherein the sub-modules include a converter unit connected in parallel with the energy storage unit.

[0074] In some embodiments, the converter unit is a power module, which includes capacitors and a half-bridge or full-bridge circuit composed of power devices such as IGBTs.

[0075] Please see Figure 2 , Figure 2 This is a flowchart illustrating a new energy power generation grid connection control method provided in an embodiment of this application. The new energy power generation grid connection control method is applied to a new energy power generation-energy storage transmission system, and the control method includes the following steps:

[0076] S100: Obtain power grid frequency information;

[0077] S200: Responds to grid frequency information to obtain inertial response data and frequency regulation data;

[0078] S300: In response to inertial response data and frequency regulation data, the new energy power generation-storage transmission system provides inertial response and frequency regulation strategies to the power grid, and the new energy power generation-storage transmission system couples the preset capacity of energy storage to the DC bus through a preset circuit.

[0079] For example, the grid frequency information is the grid frequency of grid 106; by directly coupling the energy storage of the preset capacity to the high voltage DC bus (i.e. DC submarine cable 104) of the new energy power generation-energy storage transmission system through the preset circuit, a high voltage DC direct-connected energy storage is formed, and the grid frequency of grid 106 can be mapped to the DC voltage of DC submarine cable 104 by adopting self-synchronizing voltage source control in the receiving end converter.

[0080] Based on the above, after the energy storage device 107 extracts the grid frequency information from the DC submarine cable 104, it responds to the grid frequency information to obtain inertial response data and frequency regulation data, and then provides inertial response and frequency regulation strategies to the grid based on the inertial response data and frequency regulation data; optionally, the frequency regulation strategy of the new energy power generation grid connection control method in this embodiment is a primary frequency regulation strategy.

[0081] For example, the new energy power generation grid connection control method provided in this application, targeting the grid frequency response requirements of the new energy power generation-energy storage transmission system, couples a preset capacity of energy storage to the DC bus through a preset circuit, and controls the new energy power generation-energy storage transmission system to provide inertial response and frequency regulation strategies to the grid based on inertial response data and frequency regulation data. In coordination with energy storage control, the new energy power generation-energy storage transmission system, from the perspective of the onshore grid connection point, is similar to a large synchronous generator. It can autonomously release the inertia of the wind turbine and autonomously mobilize the energy storage to participate in the primary frequency regulation of the grid, exhibiting voltage source characteristics. This enables the new energy power generation-energy storage transmission system to autonomously support the grid and provide real-time and reliable active frequency support to the grid.

[0082] In some embodiments, the new energy power generation grid connection control method further includes:

[0083] In response to grid frequency information, the receiving-end converter of the new energy power generation-storage transmission system is controlled by a self-synchronizing voltage source, and the grid frequency information and the DC bus voltage satisfy a preset relationship.

[0084] For example, the receiving-end converter adopts self-synchronizing voltage source control, and the grid frequency information and DC bus voltage satisfy a preset relationship, that is, a one-to-one correspondence is established between the grid frequency information and the DC bus voltage, so as to map the grid frequency onto the DC voltage to provide inertial response and primary frequency regulation strategy to the grid.

[0085] In some embodiments, the new energy power generation grid connection control method further includes:

[0086] The sending-end converter of the new energy power generation-storage transmission system obtains grid frequency information from the DC bus.

[0087] The grid frequency information is transmitted to the wind farm side of the new energy power generation-storage transmission system. The wind turbines on the wind farm side provide inertial response to the grid based on the grid frequency information and the AC frequency information detected by the phase-locked loop.

[0088] For example, after the sending-end converter extracts the grid frequency information from the DC bus, it transmits the grid frequency to the wind farm side of the offshore wind farm. The wind turbines of the offshore wind farm detect the AC frequency through a phase-locked loop, thereby providing an inertial response to the grid.

[0089] In some embodiments, the receiving-end converter of the new energy power generation-storage transmission system is provided with a module group, the module group including multiple sub-modules, and the control method further includes:

[0090] Based on the capacitors of multiple sub-modules in the receiving-end converter, a synchronous generator rotor simulation is performed to control the receiving-end converter to achieve phase-locked loop self-synchronization with the power grid.

[0091] For example, the receiving-end converter achieves phase-locked loop-free grid self-synchronization by analogy and simulation of the capacitors of the submodules to the rotor of a synchronous generator, thereby enabling the DC voltage on the DC bus to automatically map grid frequency changes.

[0092] In some embodiments, the new energy power generation grid connection control method further includes:

[0093] Get the number of submodules in the module group;

[0094] In response to the number of submodules, the grid frequency information is matched to the capacitor energy of the submodule according to the preset DC-side control mode of the receiving-end converter.

[0095] For example, the appropriate DC-side control method is selected according to the number of sub-modules put into operation on the DC side, so as to automatically map the grid frequency onto the DC bus voltage.

[0096] In some embodiments, the preset DC-side control mode includes a coupled control mode and a decoupled control mode. In response to the number of submodules, the grid frequency information is matched to the capacitor energy corresponding to the submodule according to the preset DC-side control mode of the receiving-end converter, including:

[0097] If the number of submodules is constant, the grid frequency information is matched to the capacitor energy of the submodule according to the coupled control method;

[0098] If the number of submodules is not a constant, the grid frequency information is matched to the capacitor energy corresponding to the submodule according to the decoupling control method.

[0099] For example, both coupled and decoupled control can automatically map the grid frequency onto the DC bus voltage. Based on this characteristic, energy storage devices and sending-end converters can obtain grid frequency information by detecting the DC voltage. The energy storage devices can respond directly, providing inertia support and primary frequency regulation. The sending-end converter can transmit the grid frequency change to each wind turbine in the offshore wind farm by changing the AC frequency of the wind farm. The wind turbines then provide a rapid frequency response to the grid. Ultimately, this achieves self-synchronizing voltage source control of the new energy power generation-energy storage transmission system, providing active frequency support to the grid.

[0100] In some embodiments, the new energy power generation grid connection control method further includes:

[0101] In response to the DC current and DC voltage on the DC side of the receiving-end converter, the DC bus voltage is controlled according to a preset dual closed-loop control strategy.

[0102] For example, rapid control of the DC bus voltage can be achieved through dual closed-loop control of the DC voltage and DC current on the DC side of the receiving-end converter; the specific details of the dual closed-loop control are described below. Figure 3 , Figure 4 .

[0103] In some embodiments, the preset capacity ranges from 15% to 20%.

[0104] In some embodiments, the new energy power generation grid connection control method further includes:

[0105] In response to the grid frequency information, the output AC voltage of the receiving-end converter of the new energy power generation-storage transmission system is controlled.

[0106] For example, by controlling the output AC voltage of the receiving-end converter, damping can be increased, thereby shortening the process time for the receiving-end converter to synchronize with the grid frequency and improving stability.

[0107] In one possible implementation, combined Figure 1 and Figure 2 The new energy power generation grid connection control method provided in this application embodiment can directly couple 15% to 20% of the system rated capacity of energy storage to the high voltage DC bus of the new energy power generation-energy storage transmission system through a preset circuit to form a high voltage DC direct-connected energy storage device.

[0108] Meanwhile, the receiving-end converter adopts self-synchronizing voltage source control to map the grid frequency onto the DC voltage. Based on this, the energy storage device extracts grid frequency information from the DC bus and provides inertial response and primary frequency regulation strategy to the grid. In addition, the sending-end converter extracts grid frequency information from the DC bus and transmits the grid frequency to the wind farm side of the offshore wind farm. The wind turbines detect the AC frequency through phase-locked loops, thereby providing inertial response to the grid.

[0109] Optionally, the receiving-end converter achieves grid self-synchronization without a phase-locked loop by analogizing the capacitors of the submodules to the rotor of a synchronous generator. The DC voltage can automatically map changes in grid frequency. Depending on whether the number of submodules connected on the DC side is constant, it can be divided into two types: coupled and decoupled. The advantage of the coupled type is that the control loop is simple and easy to implement. The advantage of the decoupled type is that the dynamic control performance of the DC voltage is better.

[0110] For example, a Modular Multilevel Converter (MMC), also known as an MMC converter, is composed of multiple cascaded sub-modules (SMs) with identical structures.

[0111] In some implementation scenarios, the specific schemes of the new energy power generation grid connection control method provided in this application embodiment are as follows:

[0112] First, calculate the total energy W of the submodule of the receiving-end MMC converter. total :

[0113]

[0114] In the formula, N is the total number of bridge arm submodules, and C SM C represents the capacitance value of the submodule (assuming all submodule capacitances are equal). SMK For the submodule voltage, W total It will be affected by the DC-side power P of the MMC dc and AC side power P ac The effects of the exchange:

[0115]

[0116] To simulate the rotor equation of a synchronous generator, the total energy W of the submodule is... total With the receiving end MMC output frequency ω rec The following relationship is established between them:

[0117]

[0118] In the text, the symbols with horizontal lines above them indicate their per-unit values. In equation (3), H v This is the virtual inertia time constant. Since the inertia provided by the MMC converter submodule capacitors is limited, therefore H... v The value should not be too large (for common projects, it is generally 30-100ms);

[0119] At this point, the receiving-end converter will possess a self-synchronization capability similar to that of a synchronous generator. For example, when the grid frequency decreases, the power angle of the receiving-end converter increases, leading to an increase in output active power and a decrease in the total energy of the submodule. Consequently, the output AC frequency of the receiving-end converter will decrease until it matches the grid frequency. However, the above characteristics only simulate the motion terms of the synchronous generator rotor equation. Due to the lack of a damping term, the process of the receiving-end MMC synchronizing with the grid frequency takes a long time and exhibits poor stability. Therefore, further adjustments can be made by regulating the output AC voltage of the receiving-end MMC. To increase damping:

[0120]

[0121] In the formula, D is the steady-state operating point for output AC power. v This is the virtual damping coefficient. The introduction of this will result in an additional damping term in the output power on the AC side:

[0122]

[0123] In the formula, This represents the per-unit value of the grid voltage at the point of connection of the receiving-end converter. This is the per-unit value of the reactance between the receiving-end converter and the equivalent synchronous machine port of the grid. Where... This is the per-unit value of the received-end MMC output AC power after introducing the damping term. The value in equation (5) is... Replace with We can obtain:

[0124]

[0125] Right now:

[0126]

[0127] This is similar to the rotor equation of a synchronous generator, where the AC side power... It can be written as:

[0128]

[0129] Through the above control, the receiving-end converter can achieve phase-locked loop-free self-synchronization with the power grid, and the energy of its sub-module capacitors will spontaneously synchronize with the grid frequency.

[0130]

[0131] Therefore, the grid frequency is mapped onto the energy of the submodule capacitor. Next, depending on the different control methods of the DC side of the receiving-end converter, it can be divided into two types: coupled and decoupled.

[0132] 1) Coupled type

[0133] Under the commonly used direct modulation method, the total number of submodules connected to the upper and lower arms of the MMC is a constant N. Therefore, the DC voltage will be coupled with the submodule voltage, i.e.:

[0134] ΔU dc =NΔUS Mav (10);

[0135] And:

[0136]

[0137] U SMav The average voltage of the submodule capacitor (U) SMavN (as rated), N is the number of submodules in each bridge arm (excluding redundancy), T MMC The time constant of the MMC submodule capacitor is typically 30–50 ms in engineering applications. Substituting equations (10), (11), and (3) into equation (9) yields:

[0138]

[0139] As mentioned above, the bandwidth of G(s) is generally greater than the grid frequency ω. g The DC voltage will remain synchronized with the grid frequency because the grid frequency generally does not deviate too far from its rated value. This balances DC voltage control with grid self-synchronization control. Due to U dc W total and ω rec The mutual coupling, the change of power grid frequency It can be naturally mapped onto DC voltage without the need for additional control.

[0140] 2) Decoupling type

[0141] Under the decoupling strategy, the total number of submodules deployed in each phase's upper and lower arms is no longer a constant, but rather an adjustable quantity N. insert .like Figure 3 As shown, Figure 3 A schematic diagram of the equivalent circuit of the DC side of the receiving-end MMC under decoupled control provided in the embodiments of this application;

[0142] Figure 3 0.5C line L represents the equivalent capacitance of a π-type DC transmission line on the DC side of the receiving-end converter. eq The DC-side equivalent inductance of the MMC typically includes the bridge arm inductance and the DC current-limiting inductance. E dc The sum of the submodule voltages applied to each phase upper and lower bridge arm of the receiving-end MMC:

[0143] E dc =N insert U SMav (12);

[0144] based on Figure 3 The equivalent circuit shown in this application is designed as follows: Figure 4 The DC voltage and DC current dual closed-loop control shown is achieved by adjusting N. insert and E dc It can realize the DC bus voltage U dc Rapid control;

[0145] like Figure 4 As shown, decoupling the DC bus voltage from the receiving-end MMC submodule voltage enhances the dynamic control performance of the DC bus voltage. Although the DC bus voltage loses its automatic mapping to grid frequency changes compared to coupled control, considering the generally slow rate of grid frequency change, a low-pass filter can be used to adjust the voltage from ω... rec (or W) total Extract the low-frequency component from the given DC voltage U, and then superimpose it onto the given DC voltage U. dcref This allows the DC voltage to reflect changes in the grid frequency. Compared to coupled control, it not only maintains the speed of tracking the grid frequency but also filters out the effects of wind power variations and grid voltage changes on the DC voltage.

[0146] It is important to note that both coupled and decoupled control systems can automatically map the grid frequency onto the DC bus voltage. Based on this characteristic, energy storage devices and sending-end converters can obtain grid frequency information by detecting the DC voltage. Energy storage devices can respond directly, providing inertia support and primary frequency regulation. The sending-end converter can change the AC frequency of the wind farm, transmitting the grid frequency change to each wind turbine, which then provides a rapid frequency response to the grid. Ultimately, this achieves self-synchronizing voltage source control of the new energy generation-energy storage transmission system, providing active frequency support to the grid. Figure 5 As shown, Figure 5 This is a schematic diagram of the topology of a new energy power generation-storage transmission system with self-synchronous voltage source control provided in an embodiment of this application.

[0147] Please see Figure 6 , Figure 6 This is a structural block diagram of a new energy power generation grid connection control device provided in an embodiment of this application. The new energy power generation grid connection control device is applied to a new energy power generation-energy storage and transmission system. The control device includes:

[0148] The power grid frequency unit 100 is used to acquire power grid frequency information;

[0149] The response unit 200 is used to respond to the power grid frequency information and obtain inertial response data and frequency modulation data.

[0150] The control unit 300 is used to respond to inertial response data and frequency regulation data to control the new energy power generation-storage transmission system to provide inertial response and frequency regulation strategies to the power grid, and the new energy power generation-storage transmission system couples the energy storage of a preset capacity to the DC bus through a preset circuit.

[0151] In some embodiments, the control unit 300 is further configured to: respond to grid frequency information, control the receiving-end converter of the new energy power generation-storage transmission system by means of self-synchronizing voltage source type control, wherein the grid frequency information and the DC bus voltage satisfy a preset relationship.

[0152] In some embodiments, the control unit 300 is further configured to: control the sending-end converter of the new energy power generation-storage transmission system to obtain grid frequency information from the DC bus; transmit the grid frequency information to the wind farm side of the new energy power generation-storage transmission system, and the wind turbines on the wind farm side provide inertial response to the grid based on the grid frequency information and the AC frequency information detected by the phase-locked loop.

[0153] In some embodiments, the receiving-end converter of the new energy power generation-storage transmission system is provided with a module group, which includes multiple sub-modules. The control unit 300 is also used to: simulate the synchronous generator rotor based on the capacitors of the multiple sub-modules in the module group using the receiving-end converter, and control the receiving-end converter to achieve phase-locked loop self-synchronization with the power grid.

[0154] In some embodiments, the control unit 300 is further configured to: acquire information on the number of submodules in the module group; and, in response to the information on the number of submodules, match the grid frequency information to the capacitor energy corresponding to the submodule according to the preset DC-side control mode of the receiving-end converter.

[0155] In some embodiments, the preset DC-side control mode includes a coupled control mode and a decoupled control mode. The control unit 300 is further configured to: if the number of sub-modules is constant, match the grid frequency information to the capacitor energy corresponding to the sub-module according to the coupled control mode; if the number of sub-modules is not constant, match the grid frequency information to the capacitor energy corresponding to the sub-module according to the decoupled control mode.

[0156] It should be noted that the new energy power generation grid connection control device provided in this application embodiment is related to... Figures 1 to 5 The method embodiments shown correspond to each other, and will not be described again here to avoid repetition.

[0157] This application also provides an electronic device, please refer to [link to application]. Figure 7 , Figure 7 This is a structural block diagram of an electronic device provided in an embodiment of this application. The electronic device may include a processor 510, a communication interface 520, a memory 530, and at least one communication bus 540. The communication bus 540 is used to enable direct communication between these components. In this embodiment, the communication interface 520 of the electronic device is used for signaling or data communication with other node devices. The processor 510 may be an integrated circuit chip with signal processing capabilities.

[0158] The processor 510 described above can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor, or the processor 510 can be any conventional processor.

[0159] The memory 530 may be, but is not limited to, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc. The memory 530 stores computer-readable instructions. When these computer-readable instructions are executed by the processor 510, the electronic device can perform the aforementioned operations. Figures 1 to 5 The various steps involved in the method implementation examples.

[0160] Alternatively, the electronic device may also include a storage controller and an input / output unit.

[0161] The memory 530, storage controller, processor 510, peripheral interface, and input / output unit are electrically connected directly or indirectly to achieve data transmission or interaction. For example, these components can be electrically connected to each other through one or more communication buses 540. The processor 510 is used to execute executable modules stored in the memory 530, such as software function modules or computer programs included in electronic devices.

[0162] The input / output unit is used to provide users with the ability to create tasks and to set optional start periods or preset execution times for those tasks, thereby enabling user-server interaction. The input / output unit may be, but is not limited to, a mouse and keyboard.

[0163] Understandable. Figure 7 The structure shown is for illustrative purposes only; the electronic device may also include components that are more advanced than those shown. Figure 7 The more or fewer components shown, or having the same Figure 7 The different configurations shown. Figure 7 The components shown can be implemented using hardware, software, or a combination thereof.

[0164] This application also provides a storage medium storing instructions. When the instructions are run on a computer, the computer program is executed by a processor to implement the method described in the method embodiment. To avoid repetition, the method will not be described again here.

[0165] This application also provides a computer program product that, when run on a computer, causes the computer to perform the method described in the method embodiment.

[0166] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0167] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0168] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0169] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0170] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0171] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A new energy power generation grid-connected control method, characterized in that, The control method is applied to a new energy power generation-energy storage sending system, and the control method comprises the following steps: obtain grid frequency information; in response to the grid frequency information, obtain inertia response data and frequency modulation data; in response to the inertia response data and the frequency modulation data, control the new energy power generation-energy storage sending system to provide inertia response and frequency modulation strategy for the grid, and the new energy power generation-energy storage sending system couples the preset capacity of energy storage to the DC bus through a preset circuit to form high-voltage DC direct-hanging energy storage.

2. The new energy power generation grid-connected control method according to claim 1, characterized in that, The control method further comprises: in response to the grid frequency information, the receiving end converter of the new energy power generation-energy storage sending system is controlled by a self-synchronous voltage source type control, and the grid frequency information and the DC bus voltage satisfy a preset relationship.

3. The new energy power generation grid-connected control method according to claim 1 or 2, characterized in that, The control method further comprises: controlling the sending end converter of the new energy power generation-energy storage sending system to obtain the grid frequency information from the DC bus; transmitting the grid frequency information to the wind farm side of the new energy power generation-energy storage sending system, and the wind turbine generator of the wind farm side detects AC frequency information based on the grid frequency information and a phase-locked loop, and provides inertia response for the grid through the AC frequency information.

4. The new energy power generation grid-connected control method according to claim 2, characterized in that, The receiving end converter of the new energy power generation-energy storage sending system is provided with a module group, the module group comprises a plurality of sub-modules, and the control method further comprises: based on the receiving end converter, the capacitors of the plurality of sub-modules in the module group are simulated as synchronous generator rotors, and the receiving end converter is controlled to be self-synchronized without phase-locked loop for the grid.

5. The new energy power generation grid-connected control method according to claim 4, characterized in that, The control method further comprises: obtain the number information of the sub-modules in the module group; in response to the number information of the sub-modules, the grid frequency information is matched with the capacitor energy corresponding to the sub-modules according to the preset DC side control mode of the receiving end converter.

6. The new energy power generation grid-connected control method according to claim 5, characterized in that, The preset DC side control mode comprises a coupling type control mode and a decoupling type control mode, and in response to the number information of the sub-modules, the grid frequency information is matched with the capacitor energy corresponding to the sub-modules according to the preset DC side control mode of the receiving end converter, which comprises: if the number information of the sub-modules is a constant, the grid frequency information is matched with the capacitor energy corresponding to the sub-modules according to the coupling type control mode; if the number information of the sub-modules is a non-constant, the grid frequency information is matched with the capacitor energy corresponding to the sub-modules according to the decoupling type control mode.

7. The new energy power generation grid-connected control method according to claim 2, characterized in that, The control method further comprises: in response to the DC current and DC voltage of the DC side of the receiving end converter, the DC bus voltage is controlled according to a preset double closed loop control strategy.

8. The new energy power generation grid-connected control method according to claim 1, characterized in that, The value range of the preset capacity is 15% to 20%.

9. The new energy power generation grid-connected control method according to claim 1, characterized in that, The control method further comprises: in response to the grid frequency information, the output AC voltage of the receiving end converter of the new energy power generation-energy storage sending system is controlled.

10. The new energy power generation grid-connected control method according to claim 1, characterized in that, The preset circuit comprises a plurality of series-connected sub-modules; wherein the sub-modules comprise a converter unit connected in parallel with an energy storage unit.

11. A new energy power generation grid-connected control device, characterized in that, The control device is applied to a new energy power generation-energy storage sending system, and the control device comprises: a grid frequency unit for obtaining grid frequency information; a response unit for obtaining inertia response data and frequency modulation data in response to the grid frequency information; A control unit is configured to control the new energy power generation and energy storage sending-out system to provide inertia response and frequency modulation strategies for a power grid in response to the inertia response data and the frequency modulation data, and the new energy power generation and energy storage sending-out system couples a preset capacity of energy storage to a DC bus through a preset circuit to form a high-voltage DC direct-hanging energy storage.

12. An electronic device, comprising: The application relates to a new energy power generation and grid connection control method and device. The application relates to a new energy power generation and grid connection control method and device.

13. A computer-readable storage medium, characterized in that, The application relates to a new energy power generation and grid connection control method and device.

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