Low voltage ride through control method and device of energy storage power station under power grid voltage fault and electronic equipment

Abstract

The application discloses a kind of low voltage ride through control method and device of energy storage power station under power grid voltage fault, wherein the method includes the coordinate transformation of measured three-phase power grid voltage and power grid current, obtains the power grid voltage vector and current vector under two-phase rotating dq coordinate system;According to the fault detection signal obtained, the power grid voltage fault state is judged, and the output power of converter is calculated based on the voltage vector and current vector according to the power grid voltage fault state;According to the output power, the current reference value is calculated, and the current reference value is adjusted using the virtual admittance current limiting method, to obtain the modulation current;Modulation voltage is calculated based on the modulation current, and three-phase switching signal is generated by converting modulation voltage signal.The application adjusts current reference value by virtual admittance current limiting method, so that energy storage converter can suppress transient current impact during fault.

Description

Technical Field

[0001] This application relates to the field of power system technology, and in particular to a low voltage ride-through control technology for energy storage power stations under grid voltage faults, specifically used for low voltage ride-through control of energy storage power stations. Background Technology

[0002] Most renewable energy power generation systems are located in remote grid areas, where grid voltage dips due to line short-circuit faults are frequent. Compared to traditional synchronous generators, energy storage converters have limited short-circuit capacity. Traditional renewable energy power generation systems typically disconnect from the grid to avoid current surges and protect equipment; however, large-scale grid disconnection can exacerbate grid faults. Therefore, to protect grid security, renewable energy power generation systems must possess corresponding low-voltage ride-through capabilities during symmetrical grid voltage dips. Furthermore, these systems must be able to provide some reactive power support to the grid while maintaining grid-connected operation to assist in grid voltage recovery.

[0003] However, while active support control strategies can provide inertia and damping for the grid, they exhibit voltage source characteristics, limiting the current control capability of energy storage converters. Furthermore, the integral component in the active support control algorithm results in slow voltage regulation, making it difficult to respond quickly to grid faults. Active support control strategies for energy storage power stations can cause severe overcurrent problems during grid voltage transients, leading to equipment damage or grid disconnection. Moreover, they struggle to provide controllable reactive power support and cannot assist in grid voltage recovery. Summary of the Invention

[0004] This disclosure provides a low-voltage ride-through control method, device, and electronic equipment for energy storage power stations under grid voltage faults, so as to at least solve the above-mentioned technical problems existing in the prior art.

[0005] According to a first aspect of this application, a low-voltage ride-through control method for an energy storage power station under grid voltage faults is provided, the method comprising:

[0006] The measured three-phase grid voltage and grid current are transformed by coordinate transformation to obtain the grid voltage vector and current vector in the two-phase rotating dq coordinate system;

[0007] The grid voltage fault status is determined based on the acquired fault detection signal, and the output power of the converter is calculated based on the grid voltage fault status, the voltage vector, and the current vector.

[0008] The current reference value is calculated based on the output power, and the current reference value is adjusted using the virtual admittance current limiting method to obtain the modulation current;

[0009] The modulation voltage is calculated based on the modulation current, and the modulation voltage signal is converted to generate a three-phase switching signal.

[0010] In one possible implementation, the converter's output power is calculated based on the voltage vector and current vector according to the grid voltage fault state.

[0011] When the grid voltage drops symmetrically, the current vector is decomposed into active support current and reactive support current, and the voltage vector is decomposed into active support voltage and reactive support voltage.

[0012] The active power reference value during low voltage ride-through is calculated using the active power support current and active power support voltage.

[0013] The reactive power reference value during low voltage ride-through is calculated using the reactive power support current and reactive power support voltage.

[0014] In one possible implementation, the converter's output power is calculated based on the grid voltage fault state, according to the voltage vector and current vector, in the following manner:

[0015]

[0016] in,

[0017] Among them, P ref，fault This is a reference value for active power during low-voltage ride-through; Q ref，fault This is a reference value for reactive power during low-voltage ride-through; U g I represents the voltage amplitude of the power grid. gN The grid current amplitude is the value of the active-supported energy storage power station operating at rated power; k is the maximum amplification factor of the grid current relative to the rated grid current during low-voltage ride-through; i gd，ref i gq，ref These are the d-axis and q-axis components of the grid current vector, respectively; u gd u gq These are the d-axis and q-axis components of the grid voltage vector, respectively; ω is the mechanical angular velocity of the synchronous generator rotor; L g For inductance; R g It is a resistor.

[0018] In one possible implementation, the current reference value is adjusted using a virtual admittance current limiting method to obtain the modulation current.

[0019]

[0020] Among them, U gdq Y is the grid voltage vector in the rotating dq coordinate system; E is the potential vector inside the virtual synchronous machine; Y is the voltage vector in the dq coordinate system.v For virtual admittance; R v and L v denoted as virtual resistance and virtual inductance, respectively; j represents the moment of inertia of the synchronous generator rotor.

[0021] In one possible implementation, the d-axis and q-axis components of the current vector are obtained based on the current reference value.

[0022]

[0023] In one possible implementation, the modulation voltage is calculated based on the modulation current in the following manner:

[0024]

[0025] Among them, u md u mq These are the output values ​​of the d-axis and q-axis PI controllers, respectively; u md u mq These are the d-axis and q-axis components of the modulated voltage signal, respectively; i gd i gq These are the d-axis and q-axis components of the grid current vector, respectively.

[0026] In one possible implementation, the conversion modulation voltage signal generates a three-phase switching signal, including:

[0027] The modulated voltage signal is transformed into a two-phase stationary αβ coordinate system through coordinate transformation.

[0028] The three-phase switching signal is generated based on the modulated voltage signal transformed into the two-phase stationary αβ coordinate system.

[0029] In one implementation, the SVPWM modulation method is used to modulate the modulation voltage signal converted to the two-phase stationary αβ coordinate system to generate a three-phase switching signal.

[0030] According to a second aspect of this application, a low-voltage ride-through control device for an energy storage power station under grid voltage faults is provided, comprising:

[0031] The transformation module is used to perform coordinate transformation on the measured three-phase grid voltage and grid current to obtain the grid voltage vector and current vector in the two-phase rotating dq coordinate system;

[0032] The calculation module is used to determine the grid voltage fault state based on the acquired fault detection signal, and calculate the output power of the converter based on the grid voltage fault state and the voltage vector and current vector.

[0033] The modulation module is used to calculate the current reference value based on the output power and adjust the current reference value using the virtual admittance current limiting method to obtain the modulation current;

[0034] The conversion module is used to calculate the modulation voltage based on the modulation current and convert the modulation voltage signal to generate a three-phase switching signal.

[0035] According to a third aspect of this application, an electronic device is provided, comprising:

[0036] At least one processor; and

[0037] A memory communicatively connected to the at least one processor; wherein,

[0038] The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method described in this application.

[0039] The beneficial effects of this invention are as follows:

[0040] Using the technical solution of this application, a low-voltage ride-through control method considering fault delay is proposed to address the problems of large transient inrush current and inability to provide controllable reactive power support to the grid in active-supported energy storage power stations under symmetrical voltage drop faults in the grid. By improving the active and reactive power control loops, the stability of the active-supported energy storage power station under voltage fault conditions is enhanced, and an improved current control inner loop is added. By changing the calculation method of the current reference value when the grid voltage fault occurs, the energy storage converter can suppress transient current inrush and provide controllable reactive power support during the fault. Subsequently, a virtual admittance current limiting method is proposed, which enables the control method to effectively suppress transient current inrush even when considering the grid fault detection delay.

[0041] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0042] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of this application are illustrated in the drawings by way of example and not limitation, in which:

[0043] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0044] Figure 1A schematic diagram illustrating the implementation process of the low-voltage ride-through control method for an energy storage power station under grid voltage faults in an embodiment of this application is shown.

[0045] Figure 2 This paper shows a schematic diagram of the low voltage ride-through control structure of an energy storage power station under grid voltage fault in an embodiment of this application.

[0046] Figure 3 This paper shows a schematic diagram of the low voltage ride-through control device of an energy storage power station under grid voltage fault in an embodiment of this application.

[0047] Figure 4 A schematic diagram of the composition structure of an electronic device according to an embodiment of this application is shown. Detailed Implementation

[0048] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0049] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0050] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0051] In the following description, the terms "first" and "second" are used merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first" and "second" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0053] It should be understood that in the various embodiments of this application, the sequence number of each implementation process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0054] The active-supported LVRT control strategy for energy storage power stations provided in this application ensures that the converter does not disconnect from the grid when the grid voltage drops symmetrically, suppressing transient inrush currents and providing reactive power to support grid voltage recovery.

[0055] Figure 1 This paper illustrates the implementation flow of the low-voltage ride-through control method for an energy storage power station under grid voltage faults in an embodiment of this application. Figure 1 .like Figure 1 As shown, the method includes:

[0056] S(Step)101, Perform coordinate transformation on the measured three-phase grid voltage and grid current to obtain the grid voltage vector and current vector in the two-phase rotating dq coordinate system;

[0057] This application measures the three-phase power grid voltage U. gabc and grid current I gabc For the measured three-phase grid voltage U gabc and grid current I gabc By performing a coordinate transformation, the grid voltage vector U in the two-phase rotating dq coordinate system is obtained. gdq and current vector I gdq Among them, the grid voltage vector U gdq Includes the d-axis and q-axis components of the grid voltage vector u gd u gq Grid current vector I gdq Including the d-axis and q-axis components of the grid current vector i gd i gq .

[0058] S102, determine the grid voltage fault state based on the acquired fault detection signal, and calculate the output power of the converter based on the grid voltage fault state, according to the voltage vector and current vector;

[0059] In some embodiments, the converter's output power is calculated based on the voltage vector and current vector according to the grid voltage fault state.

[0060] When the grid voltage drops symmetrically, the current vector is decomposed into active support current and reactive support current, and the voltage vector is decomposed into active support voltage and reactive support voltage.

[0061] The active power reference value during low voltage ride-through is calculated using the active power support current and active power support voltage.

[0062] The reactive power reference value during low voltage ride-through is calculated using the reactive power support current and reactive power support voltage.

[0063] Specifically, in this application, when the grid voltage is normal, the grid current reference value is calculated using the following method.

[0064]

[0065] Among them, I gdq，ref Z is the reference vector for the grid current. g This represents the equivalent impedance between the grid-connected converter and the power grid. The above formula can also be expressed as...

[0066]

[0067] When the grid voltage drops symmetrically, the grid current reference value is calculated to suppress overcurrent and output reactive power support current i. gd，ref To assist in the restoration of grid voltage,

[0068]

[0069] Among them, P ref，fault This is a reference value for active power during low-voltage ride-through; Q ref，fault This is a reference value for reactive power during low-voltage ride-through; U g I represents the voltage amplitude of the power grid. g N represents the grid current amplitude of the active-supported energy storage power station when operating at rated power; k represents the maximum amplification factor of the grid current relative to the rated grid current during low-voltage ride-through; i gd，ref i gq，ref These are the d-axis and q-axis components of the grid current vector, respectively; u gd u gq These are the d-axis and q-axis components of the grid voltage vector, respectively; ω is the mechanical angular velocity of the synchronous generator rotor; L g For inductance; R g It is a resistor.

[0070] When a symmetrical voltage dip fault occurs in the power grid, the required active power output P of the converter should be determined based on the actual situation of the power grid. ref，fault Then, based on the set value of parameter k and the maximum allowable capacity of the converter during a grid fault, the reference value Q of the reactive power support is calculated. ref，fault Next, the reference value of the d-axis current i is calculated according to the active and reactive power calculation formulas in the dq rotating coordinate system. gd，ref and the reference value of reactive power support current i gq，refTherefore, by setting a reasonable k value during low voltage ride-through, the inrush current can be suppressed. Furthermore, the active and reactive power capacity can be flexibly allocated according to the actual needs of the power grid, and reactive power support current can be output to the power grid to assist in the recovery of the grid voltage.

[0071] Equation (3) can also be expressed as

[0072]

[0073] In summary, when the grid voltage is normal, the low-voltage ride-through control method for energy storage power stations under grid voltage faults provided in this application only acts as a follower and does not affect the operating characteristics of the active-support type energy storage power station. When a symmetrical grid voltage drop fault occurs, it can quickly respond to the grid fault to compensate for the slow dynamic response speed of the energy storage power station, and can suppress current surges and provide reactive power support current.

[0074] S103, calculate the current reference value based on the output power, and adjust the current reference value using the virtual admittance current limiting method to obtain the modulation current;

[0075] It should be noted that this application uses a virtual admittance current limiting method to change the output impedance of the converter in order to suppress grid fault inrush current. The expression for the virtual admittance is:

[0076]

[0077] Among them, Y v For virtual admittance; R v and L v denoted as virtual resistance and virtual inductance, respectively; j represents the moment of inertia of the synchronous generator rotor.

[0078] After adopting the virtual admittance current limiting method, when the grid voltage is normal, the calculation method for the grid current reference value of the current control inner loop is as follows: By changing the selection of the virtual admittance value, the magnitude of the converter output impedance can be changed. Typically, |Y v The value of | is less than |1 / z g To achieve better rate limiting results.

[0079]

[0080]

[0081] Among them, U gdq Y is the grid voltage vector in the rotating dq coordinate system; E is the potential vector inside the virtual synchronous machine; Y is the voltage vector in the dq coordinate system. v For virtual admittance; R v and L v denoted as virtual resistance and virtual inductance, respectively; j represents the moment of inertia of the synchronous generator rotor.

[0082] S104, the modulation voltage is calculated based on the modulation current, and the modulation voltage signal is converted to generate a three-phase switching signal.

[0083] When a grid voltage dip fault occurs, due to the grid voltage fault detection delay, the calculation method of the current reference value in the current control inner loop remains the same as when the grid voltage is normal before the control system receives the grid voltage fault signal. At this time, the control system can effectively suppress transient current surges through the virtual admittance link before receiving the grid voltage fault signal. When the control system receives the fault signal, the current reference value is calculated according to equation (4). Therefore, the introduction of the virtual admittance current limiting method can enhance the ability of the proposed low voltage ride-through control strategy to suppress fault surge currents.

[0084] In some embodiments, the modulation voltage is calculated based on the modulation current in the following manner:

[0085]

[0086] Among them, u' md 、u' mq These are the output values ​​of the d-axis and q-axis PI controllers, respectively; u md u mq These are the d-axis and q-axis components of the modulated voltage signal, respectively; i gd i gq These are the d-axis and q-axis components of the grid current vector, respectively.

[0087] In some embodiments, the conversion modulation voltage signal generates a three-phase switching signal, including:

[0088] The modulated voltage signal is transformed into a two-phase stationary αβ coordinate system through coordinate transformation.

[0089] The three-phase switching signal is generated based on the modulated voltage signal transformed into the two-phase stationary αβ coordinate system.

[0090] This application utilizes the SVPWM modulation method to modulate the modulation voltage signal transformed into a two-phase stationary αβ coordinate system to generate a three-phase switching signal.

[0091] In summary, the control block diagram of the low-voltage ride-through control method for energy storage power stations under grid voltage faults proposed in this application is as follows: Figure 3 As shown. First, measure the three-phase grid voltage U. gabc and grid current I gabc The value is obtained by transforming the grid voltage vector I in the two-phase rotating dq coordinate system. gabc and current related quantity I gabcThen, the active and reactive power output of the converter are calculated based on the grid voltage and current. The grid voltage fault state is determined based on the fault detection signal to select the power feedback value of the energy storage converter, and the amplitude and angle of the internal electromotive force are obtained through an active support control algorithm. Next, the calculation method for the current reference value in the current control inner loop is selected based on the grid voltage fault state. After obtaining the grid current reference value, the modulation voltage signal of the converter is calculated. Finally, this modulation voltage signal is transformed to a two-phase stationary αβ coordinate system through coordinate transformation, and then a three-phase switching signal is generated through the SVPWM module.

[0092] like Figure 3 As shown, this application provides a low-voltage ride-through control device for an energy storage power station under grid voltage faults, the device comprising:

[0093] The transformation module 301 is used to perform coordinate transformation on the measured three-phase grid voltage and grid current to obtain the grid voltage vector and current vector in the two-phase rotating dq coordinate system;

[0094] The calculation module 302 is used to determine the grid voltage fault state based on the acquired fault detection signal, and calculate the output power of the converter based on the grid voltage fault state and the voltage vector and current vector.

[0095] The modulation module 303 is used to calculate the current reference value based on the output power and adjust the current reference value using the virtual admittance current limiting method to obtain the modulation current;

[0096] The conversion module 304 is used to calculate the modulation voltage based on the modulation current and convert the modulation voltage signal to generate a three-phase switching signal.

[0097] The working principle of the low-voltage ride-through control device for energy storage power stations under grid voltage faults provided in this application is as follows: the transformation module performs coordinate transformation on the measured three-phase grid voltage and grid current to obtain the grid voltage vector and current vector in a two-phase rotating dq coordinate system; the calculation module 302 determines the grid voltage fault state based on the acquired fault detection signal, and calculates the output power of the converter based on the grid voltage fault state and the voltage and current vectors; the modulation module 303 calculates the current reference value based on the output power, and adjusts the current reference value using the virtual admittance current limiting method to obtain the modulation current; the conversion module calculates the modulation voltage based on the modulation current, and converts the modulation voltage signal to generate a three-phase switching signal.

[0098] According to embodiments of this application, this application also provides an electronic device and a readable storage medium.

[0099] The electronic device includes at least one processor and a memory communicatively connected to the at least one processor. The memory stores instructions executable by the at least one processor, which, when executed, enable the at least one processor to perform the low-voltage ride-through control method for an energy storage power station under grid voltage faults as described in this application. The computer instructions are used to cause the computer to execute the low-voltage ride-through control method for an energy storage power station under grid voltage faults as described in this application.

[0100] This application also provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the low-voltage ride-through control method for an energy storage power station under grid voltage faults as described in this application.

[0101] Figure 4 A schematic block diagram of an example electronic device 400 that can be used to implement embodiments of this application is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the application described and / or claimed herein.

[0102] like Figure 4 As shown, device 400 includes a computing unit 401, which can perform various appropriate actions and processes based on a computer program stored in read-only memory (ROM) 402 or a computer program loaded from storage unit 408 into random access memory (RAM) 403. RAM 403 may also store various programs and data required for the operation of device 400. The computing unit 401, ROM 402, and RAM 403 are interconnected via bus 404. Input / output (I / O) interface 405 is also connected to bus 404.

[0103] Multiple components in device 400 are connected to I / O interface 405, including: input unit 406, such as keyboard, mouse, etc.; output unit 407, such as various types of monitors, speakers, etc.; storage unit 408, such as disk, optical disk, etc.; and communication unit 409, such as network card, modem, wireless transceiver, etc. Communication unit 409 allows device 400 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0104] The computing unit 401 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 401 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 401 performs the various methods and processes described above, such as the low-voltage ride-through control method for an energy storage station under grid voltage faults. For example, in some embodiments, the low-voltage ride-through control method for an energy storage station under grid voltage faults can be implemented as a computer software program tangibly contained in a machine-readable medium, such as storage unit 408. In some embodiments, part or all of the computer program can be loaded and / or installed on device 400 via ROM 402 and / or communication unit 409. When the computer program is loaded into RAM 403 and executed by the computing unit 401, one or more steps of the low-voltage ride-through control method for an energy storage station under grid voltage faults described above can be performed. Alternatively, in other embodiments, the computing unit 401 may be configured by any other suitable means (e.g., by means of firmware) to perform a low-voltage ride-through control method for an energy storage power station under grid voltage faults.

[0105] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0106] The program code used to implement the methods of this application may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0107] In the context of this application, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0108] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0109] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as a data server), or computing systems that include middleware components (e.g., an application server), or computing systems that include frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with embodiments of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., a communication network). Examples of communication networks include local area networks (LANs), wide area networks (WANs), and the Internet.

[0110] Computer systems can include clients and servers. Clients and servers are generally located far apart and typically interact via communication networks. Client-server relationships are created by computer programs running on the respective computers and having a client-server relationship with each other. Servers can be cloud servers, servers in distributed systems, or servers incorporating blockchain technology.

[0111] 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.

Claims

1. A low-voltage ride-through control method for an energy storage power station under grid voltage fault conditions. Its features are, Includes the following steps: The measured three-phase grid voltage and grid current are transformed by coordinate transformation to obtain the grid voltage vector and current vector in the two-phase rotating dq coordinate system; The grid voltage fault status is determined based on the acquired fault detection signal, and the output power of the converter is calculated based on the grid voltage fault status, the voltage vector, and the current vector. The current reference value is calculated based on the output power, and the current reference value is adjusted using the virtual admittance current limiting method to obtain the modulation current; The modulation voltage is calculated based on the modulation current, and the modulation voltage signal is converted to generate a three-phase switching signal. The converter's output power is calculated based on the grid voltage fault state, using the voltage vector and current vector. When the grid voltage drops symmetrically, the current vector is decomposed into active support current and reactive support current, and the voltage vector is decomposed into active support voltage and reactive support voltage. The active power reference value during low voltage ride-through is calculated using the active power support current and active power support voltage. The reactive power reference value during low voltage ride-through is calculated using the reactive power support current and reactive power support voltage. Based on the grid voltage fault state, the converter's output power is calculated using the voltage vector and current vector in the following manner: （1）； （2）； In formulas (1) and (2), This is a reference value for active power during low voltage ride-through. This is a reference value for reactive power during low voltage ride-through. This refers to the voltage amplitude of the power grid. The magnitude of the grid current when the active-support energy storage power station is operating at rated power; This represents the maximum amplification factor of the grid current relative to the rated grid current during low-voltage ride-through. , These are the d-axis and q-axis components of the grid current vector, respectively. , These are the d-axis and q-axis components of the grid voltage vector, respectively. This refers to the mechanical angular velocity of the synchronous generator rotor. It is an inductor; For resistance; This is the potential vector within the virtual synchronous machine.

2. The low-voltage ride-through control method for energy storage power stations under grid voltage faults as described in claim 1, Its features are, The modulation current is obtained by adjusting the current reference value using the virtual admittance current limiting method, as calculated below. （3）； （4）； In formulas (3) and (4), The grid voltage vector in the rotated dq coordinate system; The potential vector within the virtual synchronous machine; Virtual admittance; and denoted as virtual resistance and virtual inductance, respectively; j represents the moment of inertia of the synchronous generator rotor.

3. The low-voltage ride-through control method for energy storage power stations under grid voltage faults as described in claim 2, Its features are, The d-axis and q-axis components of the current vector are obtained based on the current reference value. （5）。 4. The low-voltage ride-through control method for energy storage power stations under grid voltage faults as described in claim 3. Its features are, The modulation voltage is calculated based on the modulation current using the following method. （6）； In formula (6), , These are the output values ​​of the d-axis and q-axis PI controllers, respectively. , These are the d-axis and q-axis components of the modulated voltage signal, respectively. , These are the d-axis and q-axis components of the grid current vector, respectively.

5. The low-voltage ride-through control method for energy storage power stations under grid voltage faults according to claim 1, Its features are, The conversion modulation voltage signal generates a three-phase switching signal, including: The modulated voltage signal is transformed into a two-phase stationary state through coordinate transformation. In coordinate system; Based on the transition to two-phase stillness The modulated voltage signal in the coordinate system generates a three-phase switching signal.

6. The low-voltage ride-through control method for energy storage power stations under grid voltage faults according to claim 5, Its features are, Using SVPWM modulation to switch to two-phase stationary The modulated voltage signal in the coordinate system is modulated to generate a three-phase switching signal.

7. A low-voltage ride-through control device for an energy storage power station under grid voltage faults, characterized in that, The method described in any one of claims 1-6; include: The transformation module is used to perform coordinate transformation on the measured three-phase grid voltage and grid current to obtain the grid voltage vector and current vector in the two-phase rotating dq coordinate system; The calculation module is used to determine the grid voltage fault state based on the acquired fault detection signal, and calculate the output power of the converter based on the grid voltage fault state and the voltage vector and current vector. The modulation module is used to calculate the current reference value based on the output power, and adjust the current reference value using the virtual admittance current limiting method to obtain the modulation current; The conversion module is used to calculate the modulation voltage based on the modulation current and convert the modulation voltage signal to generate a three-phase switching signal.

8. An electronic device, Its features are, Includes at least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 6.

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