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

Abstract

The invention discloses a low voltage ride through control method and device for an energy storage power station under a power grid voltage fault, and the method comprises the steps: carrying out the coordinate transformation of measured three-phase power grid voltage and power grid current, and obtaining a power grid voltage vector and a current vector under a two-phase rotation dq coordinate system; judging a power grid voltage fault state according to the obtained fault detection signal, and calculating the output power of the converter based on the power grid voltage fault state according to the voltage vector and the current vector; calculating a current reference value according to the output power, and adjusting the current reference value by using a virtual admittance current limiting method to obtain a modulation current; modulation voltage is calculated based on the modulation current, and a modulation voltage signal is converted to generate a three-phase switching signal. According to the invention, the current reference value is adjusted through the virtual admittance current limiting method, so that the energy storage converter can suppress transient current impact during the fault period.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to a low voltage ride through control technology for an energy storage power station under a grid voltage fault, specifically for low voltage ride through control of an energy storage power station. Background Art

[0002] Most renewable energy power generation systems are distributed in remote power grid areas, and grid voltage drop failures caused by line short-circuit failures occur from time to time. Compared with traditional synchronous generators, the short-circuit capacity of energy storage converters is limited. Traditional renewable energy power generation systems usually take the approach of disconnecting from the grid to avoid current shocks and protect equipment, but large-scale power generation system disconnection will aggravate grid failures. Therefore, in order to protect the safety of the power grid, when a symmetrical grid voltage drop failure occurs, the renewable energy power generation system is required to have the corresponding low voltage ride-through capability, and the power generation system is required to provide a certain amount of reactive power support to the grid while maintaining grid-connected operation to assist in grid voltage recovery.

[0003] However, although the active support control strategy can provide inertia and damping for the power grid, it has a voltage source-type external characteristic, which limits the energy storage converter's ability to control current. At the same time, the integral link in the active support control algorithm causes its voltage regulation to be slow, making it difficult to respond quickly to power grid faults. The active support control strategy of the energy storage power station will cause serious overcurrent problems when the grid voltage drops transiently, causing equipment damage or disconnection from the grid, and it is difficult to provide controllable reactive power support and cannot assist in the recovery of the grid voltage. Summary of the invention

[0004] The present disclosure provides a low voltage ride through control method, device and electronic equipment of an energy storage power station under a grid voltage fault, so as to at least solve the above technical problems existing in the prior art.

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

[0006] Performing 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;

[0007] Determine a grid voltage fault state according to the acquired fault detection signal, and calculate the output power of the converter according to the voltage vector and the current vector based on the grid voltage fault state;

[0008] Calculating a current reference value according to the output power, and adjusting the current reference value using a virtual admittance current limiting method to obtain a modulated current;

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

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

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

[0012] Calculating an active power reference value during low voltage ride through using the active support current and the active support voltage;

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

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

[0015]

[0016] in,

[0017] Among them, P ref，fault is the active power reference value during low voltage ride-through; Q ref，fault is the reactive power reference value during low voltage ride-through; U g is the grid voltage amplitude; I gN is the grid current amplitude when the active supporting energy storage power station operates at rated power; k is the maximum magnification of the grid current allowed during low voltage ride-through relative to the rated grid current; i gd，ref 、i gq，ref are the d-axis and q-axis components of the grid current vector respectively; u gd 、u gq 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 is the inductance; R g For resistance.

[0018] In one possible implementation manner, the current reference value is adjusted using a virtual admittance current limiting method using the following calculation method to obtain a modulated current:

[0019]

[0020] Among them, U gdq is the grid voltage vector in the rotating dq coordinate system; E is the potential vector inside the virtual synchronous machine; Yv is the virtual admittance; R v and L v are the virtual resistance and virtual inductance respectively; j is 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 according to 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 are the output values ​​of the PI controllers of the d and q axes respectively; u md 、u mq are the d-axis and q-axis components of the modulation voltage signal respectively; i gd 、i gq They are the d and q axis components of the grid current vector respectively.

[0026] In one possible implementation manner, converting the modulated voltage signal to generate a three-phase switching signal includes:

[0027] Converting the modulated voltage signal into a two-phase stationary αβ coordinate system through coordinate transformation;

[0028] A three-phase switching signal is generated according to the modulated voltage signal converted into a two-phase stationary αβ coordinate system.

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

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

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

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

[0033] A modulation module, used for calculating a current reference value according to the output power, and adjusting the current reference value by using a virtual admittance current limiting method to obtain a 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 switch signal.

[0035] According to a third aspect of the present application, an electronic device is provided, including:

[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, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method described in the present application.

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

[0040] By utilizing the technical solution of the present application, a low voltage ride-through control method that takes fault delay into consideration is proposed to address the problems of large transient impact current and inability to provide controllable reactive power support to the grid in an active support type energy storage power station under a symmetrical grid voltage drop fault. The stability of the active support type energy storage power station under voltage fault conditions is improved by improving the active and reactive power control loops, and an improved current control inner loop is added. By changing the calculation method of the current reference value when a grid voltage fault occurs, the energy storage converter can suppress transient current impacts and provide controllable reactive power support during the fault. Subsequently, a virtual admittance current limiting method is proposed, so that the control method can also effectively suppress transient current impacts while taking into account the grid fault detection delay.

[0041] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present application, nor is it intended to limit the scope of the present application. Other features of the present application will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present application will become readily understood. In the accompanying drawings, several embodiments of the present application are shown in an exemplary and non-limiting manner, wherein:

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

[0044] Figure 1A schematic diagram of the implementation process of the low voltage ride-through control method of the energy storage power station under the grid voltage fault in the embodiment of the present application is shown;

[0045] Figure 2 A schematic diagram of the low voltage ride through control structure of the energy storage power station under a grid voltage fault in an embodiment of the present application is shown;

[0046] Figure 3 A schematic diagram of the structure of a low voltage ride through control device of an energy storage power station under a grid voltage fault in an embodiment of the present application is shown;

[0047] Figure 4 A schematic diagram of the structure of an electronic device in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0048] In order to make the purpose, features, and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0049] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0050] In the following description, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it can be 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\second" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present 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 those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0053] It should be understood that in the various embodiments of the present application, the size of the serial number of each implementation process does not mean 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 the present application.

[0054] The LVRT control strategy of the active support type energy storage power station provided in the present application is that when the grid voltage drops symmetrically, the converter does not go off the grid, the transient impact current is suppressed, and reactive power can be provided to support the grid voltage recovery.

[0055] Figure 1 The schematic diagram shows the implementation process of the low voltage ride through control method of the energy storage power station under the grid voltage fault in the embodiment of the present application. Figure 1 .like Figure 1 As shown, the method includes:

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

[0057] This application measures the three-phase grid voltage U gabc and grid current I gabc , for the measured three-phase grid voltage U gabc and grid current I gabc Perform coordinate transformation to obtain the grid voltage vector U in the two-phase rotating dq coordinate system gdq and the current vector I gdq Among them, the grid voltage vector U gdq Including the d and q axis components u of the grid voltage vector gd 、u gq , grid current vector I gdq Including the d and q axis components i of the grid current vector gd 、i gq .

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

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

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

[0061] Calculating an active power reference value during low voltage ride through using the active support current and the active support voltage;

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

[0063] Specifically, in this application, when the grid voltage is normal, the grid current reference value is calculated in the following manner:

[0064]

[0065] Among them, I gdq，ref is the grid current reference value vector, Z g is the equivalent impedance between the grid-connected converter and the 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 support current i gd，ref To assist in grid voltage recovery,

[0068]

[0069] Among them, P ref，fault is the active power reference value during low voltage ride-through; Q ref，fault is the reactive power reference value during low voltage ride-through; U g is the grid voltage amplitude; I g N is the grid current amplitude when the active supporting energy storage power station operates at rated power; k is the maximum magnification of the grid current allowed during low voltage ride-through relative to the rated grid current; i gd，ref 、i gq，ref are the d-axis and q-axis components of the grid current vector respectively; u gd 、u gq 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 is the inductance; R g For resistance.

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

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

[0072]

[0073] In summary, when the grid voltage is normal, the low voltage ride-through control method of the energy storage power station under grid voltage fault provided by this application only plays the role of 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 disadvantage of the slow dynamic response speed of the energy storage power station, and can suppress current shock and provide reactive support current.

[0074] S103, calculating a current reference value according to the output power, and adjusting the current reference value using a virtual admittance current limiting method to obtain a modulated current;

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

[0076]

[0077] Among them, Y v is the virtual admittance; R v and L v are the virtual resistance and virtual inductance respectively; j is 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 current control inner loop current reference value calculation method adopts the following method. By changing the selection of the virtual admittance value, the size of the converter output impedance can be changed. Usually |Y v The value of | is less than |1 / z g |To achieve better current limiting effect.

[0079]

[0080]

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

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

[0083] When a grid voltage drop fault occurs, due to the existence of grid voltage fault detection delay, when the control system does not receive the grid voltage fault signal, the calculation method of the current reference value in the current control inner loop is still the same as when the grid voltage is normal. At this time, the control system can effectively suppress the transient current impact 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 formula (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 impact current.

[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 are the output values ​​of the PI controllers of the d and q axes respectively; u md 、u mq are the d-axis and q-axis components of the modulation voltage signal respectively; i gd 、i gq They are the d and q axis components of the grid current vector respectively.

[0087] In some embodiments, converting the modulated voltage signal to generate a three-phase switching signal includes:

[0088] Converting the modulated voltage signal into a two-phase stationary αβ coordinate system through coordinate transformation;

[0089] A three-phase switching signal is generated according to the modulated voltage signal converted into a two-phase stationary αβ coordinate system.

[0090] The present application utilizes the SVPWM modulation method to modulate the modulation voltage signal converted 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 of the energy storage power station under the grid voltage fault proposed in this application is as follows: Figure 3 First, measure the three-phase grid voltage U gabc and grid current I gabc The grid voltage vector I in the two-phase rotating dq coordinate system is obtained by Wubiao transformation. gabc and current switch I gabc. Then, the active power and reactive power output by the converter are calculated based on the grid voltage and current. The grid voltage fault state is judged according to the fault detection signal to select the power feedback value of the energy storage converter, and the amplitude and angle of the internal potential are obtained through the active support control algorithm. Next, the calculation method of the current reference value in the current control inner loop is selected according to the grid voltage fault state, and the modulation voltage signal of the converter is calculated after the grid current reference value is obtained. Finally, this modulated voltage signal is converted 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, the present application provides a low voltage ride through control device for an energy storage power station under a grid voltage fault, 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 a two-phase rotating dq coordinate system;

[0094] A calculation module 302, configured to determine a grid voltage fault state according to the acquired fault detection signal, and calculate the output power of the converter according to the voltage vector and the current vector based on the grid voltage fault state;

[0095] A modulation module 303, configured to calculate a current reference value according to the output power, and adjust the current reference value using a virtual admittance current limiting method to obtain a modulation current;

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

[0097] The working principle of the low voltage ride-through control device of the energy storage power station under the grid voltage fault provided in the present application is that 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 the two-phase rotating dq coordinate system; the calculation module 302 determines the grid voltage fault state according to the acquired fault detection signal, and calculates the output power of the converter according to the voltage vector and current vector based on the grid voltage fault state; the modulation module 303 calculates the current reference value according to the output power, and adjusts the current reference value by using the virtual admittance current limiting method to obtain the modulated current; the conversion module obtains the modulation voltage based on the modulation current, and converts the modulation voltage signal to generate a three-phase switching signal.

[0098] According to an embodiment of the present application, the present application also provides an electronic device and a readable storage medium.

[0099] The electronic device includes at least one processor; and a memory in communication with the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the low voltage ride-through control method of the energy storage power station under the grid voltage fault described in the present application. The computer instructions are used to enable the computer to execute the low voltage ride-through control method of the energy storage power station under the grid voltage fault described in the present application.

[0100] The present 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 of an energy storage power station under a grid voltage fault of the present application.

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

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

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

[0104] The computing unit 401 may be a variety of general and / or special 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 dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 401 performs the various methods and processes described above, such as a low voltage ride-through control method for an energy storage power station under a grid voltage fault. For example, in some embodiments, a low voltage ride-through control method for an energy storage power station under a grid voltage fault may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit 408. In some embodiments, part or all of the computer program may be loaded and / or installed on the device 400 via the ROM 402 and / or the communication unit 409. When the computer program is loaded into the 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 power station under a grid voltage fault described above may be performed. Alternatively, in other embodiments, the computing unit 401 may be configured in any other appropriate manner (for example, by means of firmware) to execute the low voltage ride through control method of the energy storage power station under grid voltage fault.

[0105] Various implementations 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 chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0106] The program code for implementing the method of the present application can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that the program code, when executed by the processor or controller, implements the functions / operations specified in the flow chart and / or block diagram. The program code can be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0107] In the context of the present application, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, 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 (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the 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 acoustic input, voice input, or tactile input).

[0109] The systems and techniques described herein may be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), and the Internet.

[0110] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The relationship of client and server is generated by computer programs running on respective computers and having a client-server relationship with each other. The server may be a cloud server, a server of a distributed system, or a server combined with a blockchain.

[0111] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A low voltage ride through control method for an energy storage power station under a grid voltage fault. It is characterized in that The steps include: Performing 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; Determine a grid voltage fault state according to the acquired fault detection signal, and calculate the output power of the converter according to the voltage vector and the current vector based on the grid voltage fault state; Calculating a current reference value according to the output power, and adjusting the current reference value using a virtual admittance current limiting method to obtain a modulated current; A modulation voltage is calculated based on the modulation current, and a modulation voltage signal is converted to generate a three-phase switching signal.

2. The low voltage ride through control method of the energy storage power station under the grid voltage fault according to claim 1, It is characterized in that The step of calculating the output power of the converter according to the voltage vector and the current vector based on the grid voltage fault state, When the grid voltage drops symmetrically, the current vector is decomposed into an active support current and a reactive support current, and the voltage vector is decomposed into an active support voltage and a reactive support voltage; Calculating an active power reference value during low voltage ride through using the active support current and the active support voltage; The reactive power reference value during the low voltage ride through period is calculated using the reactive support current and the reactive support voltage.

3. The low voltage ride through control method of the energy storage power station under the grid voltage fault according to claim 1, It is characterized in that The output power of the converter is calculated based on the voltage vector and the current vector according to the grid voltage fault state in the following manner: In formula (1) and formula (2), P ref，fault is the active power reference value during low voltage ride-through; Q ref，fault is the reactive power reference value during low voltage ride-through; U g is the grid voltage amplitude; I gN is the grid current amplitude when the active supporting energy storage power station operates at rated power; k is the maximum magnification of the grid current allowed during low voltage ride-through relative to the rated grid current; i gd，ref 、i gq，ref , are the d-axis and q-axis components of the grid current vector respectively; u gd 、u gq 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 is the inductance; R g For resistance.

4. The low voltage ride through control method of the energy storage power station under the grid voltage fault according to claim 1, It is characterized in that The current reference value is adjusted using the virtual admittance current limiting method by the following calculation method to obtain the modulation current: In formula (3) and formula (4), U gdq is the grid voltage vector in the rotating dq coordinate system; E is the potential vector inside the virtual synchronous machine; Y v is the virtual admittance; R v and L v are the virtual resistance and virtual inductance respectively; j is the moment of inertia of the synchronous generator rotor.

5. The low voltage ride through control method of the energy storage power station under the grid voltage fault according to claim 4, It is characterized in that According to the current reference value, the d-axis and q-axis components of the current vector are obtained.

6. The low voltage ride through control method of the energy storage power station under the grid voltage fault according to claim 5, It is characterized in that The modulation voltage is calculated based on the modulation current in the following manner: In formula (6), u md 、u mq are the output values ​​of the PI controllers of the d and q axes respectively; u md 、u mq are the d-axis and q-axis components of the modulation voltage signal respectively; i gd 、i gq They are the d-axis and q-axis components of the grid current vector respectively.

7. The low voltage ride through control method of the energy storage power station under the grid voltage fault according to claim 1, It is characterized in that The converting the modulated voltage signal to generate a three-phase switching signal comprises: Converting the modulated voltage signal into a two-phase stationary αβ coordinate system through coordinate transformation; A three-phase switching signal is generated according to the modulated voltage signal converted into a two-phase stationary αβ coordinate system.

8. The low voltage ride through control method of the energy storage power station under grid voltage fault according to claim 7, It is characterized in that The modulation voltage signal converted into the two-phase stationary αβ coordinate system is modulated using the SVPWM modulation method to generate a three-phase switching signal.

9. A low voltage ride through control device for an energy storage power station under grid voltage failure. It is characterized in that include: A transformation module is used to perform coordinate transformation on the measured three-phase grid voltage and grid current to obtain a grid voltage vector and a current vector in a two-phase rotating dq coordinate system; A calculation module, used to determine the grid voltage fault state according to the acquired fault detection signal, and calculate the output power of the converter according to the voltage vector and the current vector based on the grid voltage fault state; A modulation module, used for calculating a current reference value according to the output power, and adjusting the current reference value by using a virtual admittance current limiting method to obtain a 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 switch signal.

10. An electronic device, It is characterized in that comprising 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, and the instructions are 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 8.

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