Fault ride-through method based on converter control

Abstract

The invention provides a fault ride-through method based on converter control. The working state of the target current converter is determined by detecting the first parameter of the target current converter, so that whether the current power station breaks down or not is determined, and the specific form of the first parameter can be electrical parameters such as the outlet current of the target current converter and the change condition along with time. Furthermore, through the first parameter obtained through detection, a current limiting coefficient can be determined, then a second parameter of each sub-module is determined, and the number of converter sub-modules put into operation and a corresponding bridge arm voltage reference value are determined, so that fault current increase in a transient stage can be limited, and the purpose of fault ride-through can be achieved. By detecting and controlling the target converter in real time, continuous self-adaptive control can be realized, control delay caused by a communication mode is reduced, components such as a bleeder resistor do not need to be added, and equipment cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of direct current grid control technology, and in particular to a fault ride-through method based on converter control. Background Art

[0002] In the field of renewable energy power generation, power transmission is mostly completed by feeding into the public power grid through long-distance transmission lines and multiple transformers. The grid-connected inverter, as the energy conversion interface between renewable energy and the power grid, is the core equipment of the renewable energy grid-connected power generation system. Traditional grid-connected inverters lack voltage support control capabilities and have low stability in weak grids under complex working conditions. Therefore, starting from the renewable energy grid-connected inverter equipment itself, a voltage support control solution based on the renewable energy grid-connected inverter can be designed to solve such problems.

[0003] However, the existing active voltage support control method for grid-connected inverters in the field of new energy has poor voltage support performance, resulting in poor control effect. Specifically, under complex working conditions, although in some feasible implementations, the voltage of the power grid is used as an input parameter of the grid-connected inverter for control, the adaptive support control capability based on specific working conditions in a weak grid environment is insufficient. Therefore, a fault ride-through method based on converter control is needed to improve the adaptive capability and voltage stabilization performance of the grid-connected inverter to the working conditions. Summary of the invention

[0004] The purpose of the present application is to solve at least one of the above-mentioned technical defects, especially the technical defect of the active voltage support control method of the grid-connected inverter in the prior art, which has poor voltage support performance and thus leads to poor control effect.

[0005] In a first aspect, the present application provides a fault ride-through method based on converter control, which detects a first parameter of a target converter;

[0006] Wherein, the target converter includes a plurality of initial converter submodules;

[0007] And, the first parameter is used to indicate the working state of the target converter;

[0008] Determining a current limiting coefficient according to the first parameter;

[0009] Determining a second parameter of each of the initial converter submodules according to the current limiting coefficient, and controlling a working state of each of the initial converter submodules according to the second parameter;

[0010] The working state includes a running state and a disconnected state.

[0011] As an optional implementation, the first parameter includes a port DC current of the target converter;

[0012] Determining the current limiting coefficient according to the first parameter includes:

[0013] determining whether the target converter is in a fault state according to the port DC current;

[0014] If the target converter is in a fault state, a current limiting coefficient is obtained by calculation according to the port DC current;

[0015] If the target converter is in a normal state, the DC current at the port of the target converter is continuously detected.

[0016] As an optional implementation manner, determining whether the target converter is in a fault state according to the port DC current includes:

[0017] According to the port DC current, obtaining a delayed DC current after a fixed delay, and calculating a first difference between the port DC current and the delayed DC current;

[0018] If the first difference is greater than a preset start threshold, it is determined that the target converter is in a fault state, and the first difference is used as a start signal.

[0019] As an optional implementation, the calculating and obtaining the current limiting coefficient according to the port DC current includes:

[0020] According to the start signal, a first frequency domain signal is obtained, and the first frequency domain signal is processed by a preset controller to obtain a second frequency domain signal;

[0021] Obtaining a first time domain signal after inverse Laplace transformation according to the second frequency domain signal;

[0022] A second difference between the start signal and the first time domain signal is calculated, and the second difference is used as a current limiting coefficient.

[0023] As an optional implementation, the second parameter includes the number of operating submodules and a DC voltage reference value of each submodule, and the determining the second parameter of each initial converter submodule according to the current limiting coefficient includes:

[0024] Determining the number of operating submodules according to the product of the current limiting coefficient and the number of initial converter submodules;

[0025] The DC voltage reference value of each submodule in operation is determined according to the product of the current limiting coefficient and the initial value of the DC voltage of each submodule.

[0026] As an optional implementation, the initial number of converter submodules on the three-phase circuit of the target converter is consistent, and the operating number of converter submodules on the three-phase circuit of the target converter is consistent.

[0027] As an optional implementation, the converter submodule includes a half-bridge converter submodule.

[0028] In a second aspect, the present application provides a fault ride-through device based on converter control, the device comprising:

[0029] A detection module, used for detecting a first parameter of a target converter;

[0030] Wherein, the target converter includes a plurality of initial converter submodules;

[0031] And, the first parameter is used to indicate the working state of the target converter;

[0032] A processing module, used for determining a current limiting coefficient according to the first parameter;

[0033] The processing module is further used to determine a second parameter of each of the initial converter submodules according to the current limiting coefficient, and control a working state of each of the initial converter submodules according to the second parameter;

[0034] The working state includes a running state and a disconnected state.

[0035] In a third aspect, the present application provides a computer device comprising one or more processors and a memory, wherein the memory stores computer-readable instructions, and when the computer-readable instructions are executed by the one or more processors, the steps of the method described in the first aspect are performed.

[0036] In a fourth aspect, the present application provides a storage medium storing computer-readable instructions, which, when executed by one or more processors, causes the one or more processors to perform the steps of the method described in the first aspect.

[0037] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0038] Based on any of the above embodiments, the present application determines the working state of the target converter by detecting the first parameter of the target converter, thereby determining whether the current power station has a fault, and the specific form of the first parameter can be the electrical parameters such as the outlet current of the target converter itself and their changes over time. Furthermore, by detecting the first parameter obtained, the current limiting coefficient can be determined, and then the second parameter of each submodule can be determined, and the number of converter submodules put into operation and the corresponding bridge arm voltage reference value can be determined, so as to limit the growth of fault current in the transient stage to achieve the purpose of fault crossing. By performing real-time detection and control of the target converter, continuous adaptive control can be achieved, reducing the control delay caused by the communication method, and there is no need to add components such as discharge resistors, thereby reducing equipment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0040] Figure 1 A schematic diagram of a power grid structure of a fault ride-through method based on converter control provided in one embodiment of the present application;

[0041] Figure 2 A schematic flow chart of a fault ride-through method based on converter control provided in one embodiment of the present application;

[0042] Figure 3 A schematic diagram of the structure of a converter provided in one embodiment of the present application;

[0043] Figure 4 A control logic diagram of a fault ride-through method based on converter control provided by one embodiment of the present application;

[0044] Figure 5 This is a diagram of the internal structure of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions 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 ordinary technicians in this field without creative work are within the scope of protection of this application.

[0046] With the construction of new power systems based on new energy, wind and solar energy in deserts, Gobi deserts, and other areas, as well as wind energy in deep and distant seas, have been further utilized. In the above scenarios, large-scale power stations are usually built to centrally develop and convert new energy, and the power output of each unit is collected and then uniformly sent out and connected to the grid.

[0047] For details, please refer to Figure 1 , Figure 1 A schematic diagram of the grid structure of a fault ride-through method based on converter control provided for an embodiment of the present application is specifically a system structure of a photovoltaic power station connected to the grid via a flexible DC grid-connected system. Large-scale photovoltaic power stations are mostly distributed in the western region and need to be transmitted to the load center in the east through long-distance, large-capacity transmission lines to achieve grid connection. Flexible DC transmission technology has the advantages of flexible operation and regulation, avoiding commutation failure, and no need for reactive power compensation. It is the preferred technical solution for grid-connected transmission of large-scale photovoltaic power stations. However, the flexible DC transmission system has low damping, and the speed of fault development and spread is fast, which will significantly affect the power transmission and stable operation of the photovoltaic power station, thereby reducing the power safety of the receiving system and the ability to absorb new energy.

[0048] In order to prevent photovoltaic power stations from being affected by DC system faults and AC system faults at the receiving end, it is of great significance to study the fault ride-through method of photovoltaic power stations. At present, the fault ride-through methods of photovoltaic power stations are mainly divided into methods based on communication links and methods based on configuring bleeder resistors, which are difficult to meet engineering requirements in terms of control speed and equipment cost.

[0049] The present application proposes a photovoltaic power station fault ride-through method based on active current limiting control of the converter, which detects the change of the converter outlet current, adjusts the converter bridge arm voltage reference value and the number of submodules put into operation, thereby limiting the growth of the fault current in the transient stage and realizing the fault ride-through of the photovoltaic power station. The method can realize continuous adaptive limitation of the fault current, avoid the control delay caused by communication, and do not need to consider the equipment cost due to the configuration of the discharge resistor. Specifically, the technical concept of the present application is to determine the working state of the target converter by detecting the first parameter of the target converter, so as to determine whether the current power station has a fault, and the specific form of the first parameter can be the electrical parameters such as the outlet current of the target converter and the change over time. Further, by detecting the first parameter obtained, the current limiting coefficient can be determined, and then the second parameter of each submodule can be determined, and the number of converter submodules put into operation and the corresponding bridge arm voltage reference value can be determined, so that the growth of the fault current in the transient stage can be limited to achieve the purpose of fault ride-through. By real-time detection and control of the target converter, continuous adaptive control can be achieved, reducing the control delay caused by the communication method, and there is no need to add components such as bleeder resistors, thereby reducing equipment costs.

[0050] See also Figure 2 , Figure 2 A schematic diagram of a flow chart of a fault ride-through method based on converter control provided in one embodiment of the present application is shown in FIG. Figure 2 As shown, the method includes:

[0051] S101, detecting a first parameter of a target converter;

[0052] Wherein, the target converter includes a plurality of initial converter submodules;

[0053] And, the first parameter is used to indicate the working state of the target converter;

[0054] In a specific implementation, the first parameter may be a port DC current, which is easy to detect and can better reflect the working condition of the converter. In application, the working condition of the target converter can be determined by judging whether the value of the first parameter exceeds the corresponding threshold value, or whether the index such as the rate of change of the first parameter exceeds the corresponding threshold value.

[0055] S102, determining a current limiting coefficient according to the first parameter;

[0056] The current limiting coefficient can be a global constant or a specific coefficient corresponding to each parameter. The current limiting coefficient can be obtained through modeling calculation or parameter optimization.

[0057] S103, determining a second parameter of each of the initial converter submodules according to the current limiting coefficient, and controlling a working state of each of the initial converter submodules according to the second parameter;

[0058] The working state includes a running state and a disconnected state.

[0059] The second parameter is used to adjust the working state of each submodule in the target converter, so that the target converter can ensure safe operation under fault conditions, and restore the corresponding parameters according to further adjustment instructions after the fault ends, thereby achieving fault ride-through.

[0060] As an optional implementation manner, the first parameter includes a port DC current of the target converter;

[0061] Determining the current limiting coefficient according to the first parameter includes:

[0062] determining whether the target converter is in a fault state according to the port DC current;

[0063] If the target converter is in a fault state, a current limiting coefficient is obtained by calculation according to the port DC current;

[0064] If the target converter is in a normal state, the DC current at the port of the target converter is continuously detected.

[0065] As mentioned above, in this embodiment, the first parameter may include the port DC current of the target converter. Specifically, it can be determined whether the target converter is in a fault state through the situation of the port DC current of the target converter itself and the change of the port DC current over time, and trigger the execution of the current limiting control scheme when the converter is in a fault state, thereby realizing real-time monitoring and control, and improving the real-time and effectiveness of the control.

[0066] As an optional implementation manner, determining whether the target converter is in a fault state according to the port DC current includes:

[0067] According to the port DC current, obtaining a delayed DC current after a fixed delay, and calculating a first difference between the port DC current and the delayed DC current;

[0068] If the first difference is greater than a preset start threshold, it is determined that the target converter is in a fault state, and the first difference is used as a start signal.

[0069] The difference between the port DC current and the DC current after a fixed delay can be used to obtain the change in the current port DC current. Therefore, when the change in the port DC current exceeds the preset start-up threshold, it is determined that there is a fault in the target converter and the corresponding equipment, and current limiting is required to cross the fault, thereby realizing real-time monitoring of the fault and improving the real-time and effectiveness of detection and control.

[0070] As an optional implementation manner, the calculating and obtaining the current limiting coefficient according to the port DC current includes:

[0071] According to the start signal, a first frequency domain signal is obtained, and the first frequency domain signal is processed by a preset controller to obtain a second frequency domain signal;

[0072] Obtaining a first time domain signal after inverse Laplace transformation according to the second frequency domain signal;

[0073] A second difference between the start signal and the first time domain signal is calculated, and the second difference is used as a current limiting coefficient.

[0074] By performing Laplace transform on the start signal, a start signal in the frequency domain, i.e., a first frequency domain signal, is obtained, and the start signal in the frequency domain is processed by a controller transfer function to obtain a second frequency domain signal, and the second frequency domain signal is further subjected to an inverse Laplace transform to obtain a corresponding time domain signal, thereby calculating a difference based on the start signal and the processed first time domain signal to obtain a corresponding current limiting coefficient. The current limiting coefficient calculated in this way is directly related to the DC current of the port, thereby improving the effectiveness of control.

[0075] As an optional implementation manner, the second parameter includes the number of operating submodules and a DC voltage reference value of each submodule, and the second parameter of each initial converter submodule is determined according to the current limiting coefficient, including:

[0076] Determining the number of operating submodules according to the product of the current limiting coefficient and the number of initial converter submodules;

[0077] The DC voltage reference value of each submodule in operation is determined according to the product of the current limiting coefficient and the initial value of the DC voltage of each submodule.

[0078] This embodiment determines the number of sub-modules that need to be in operation at present by multiplying the determined current limiting coefficient with the number of initial converter sub-modules, and obtains the current DC voltage reference value of each sub-module by multiplying the current limiting coefficient with the initial value of the bridge arm DC voltage corresponding to each sub-module. Thus, the operating state and operating parameters of each sub-module are specifically controlled, which reduces equipment costs and improves control efficiency while also improving control effectiveness.

[0079] like Figure 3 As shown, Figure 3 A schematic diagram of a converter structure provided for an embodiment of the present application, as an optional implementation, the initial number of converter submodules on the three-phase circuit of the target converter is consistent, and the operating number of converter submodules on the three-phase circuit of the target converter is consistent.

[0080] In the present application, the target inverter three-phase circuit is configured with the same number of initial inverter sub-modules, and the number of operating inverter sub-modules is ensured to be consistent during the control process, so that the circuit parameters can be kept balanced, thereby improving the stability of the circuit during the control process.

[0081] As an optional implementation, the converter submodule includes a half-bridge converter submodule.

[0082] The converter submodule in the present application may be in the form of a half-bridge converter submodule, which has a simple structure, can reduce structural costs, and is easy to implement the control method in each embodiment.

[0083] like Figure 4 As shown, Figure 4 A control logic diagram of a fault ride-through method based on converter control provided by an embodiment of the present application is provided. The figure omits the transformation link from time domain to frequency domain. When the aforementioned embodiments are implemented in combination, the method may include:

[0084] Real-time monitoring of the DC current at the converter ports ,in, For the moment, Represents a fixed time delay, when the DC current Exceeding the start threshold When the main current limiting control is started;

[0085] based on Figure 4 The control block diagram shown is composed of Real-time calculation of current limiting coefficient , in the figure, represents the proportionality coefficient, represents the integral coefficient;

[0086] By the current limiting factor Real-time control of the number of submodules in the converter and DC voltage reference ,in, for , for , is the initial number of submodules, is the initial DC voltage reference value;

[0087] exist and Controlled stage, is suppressed, thus realizing active current limiting of the converter;

[0088] Since the fault current is limited, the current indicator at the grid connection point of the photovoltaic power station does not exceed the limit during the fault process, so the photovoltaic power station remains in grid operation, thereby achieving fault ride-through.

[0089] The embodiment of the present application further provides a fault ride-through device based on converter control, the device comprising:

[0090] A detection module, used for detecting a first parameter of a target converter;

[0091] Wherein, the target converter includes a plurality of initial converter submodules;

[0092] And, the first parameter is used to indicate the working state of the target converter;

[0093] A processing module, used for determining a current limiting coefficient according to the first parameter;

[0094] The processing module is further used to determine a second parameter of each of the initial converter submodules according to the current limiting coefficient, and control a working state of each of the initial converter submodules according to the second parameter;

[0095] The working state includes a running state and a disconnected state.

[0096] The present application determines the working state of the target converter by detecting the first parameter of the target converter, thereby determining whether the current power station has a fault, and the specific form of the first parameter can be the electrical parameters such as the outlet current of the target converter itself and their changes over time. Furthermore, by detecting the first parameter obtained, the current limiting coefficient can be determined, and then the second parameter of each submodule can be determined, and the number of converter submodules put into operation and the corresponding bridge arm voltage reference value can be determined, so as to limit the growth of fault current in the transient stage to achieve the purpose of fault crossing. By real-time detection and control of the target converter, continuous adaptive control can be achieved, reducing the control delay caused by the communication method, and there is no need to add components such as discharge resistors, thereby reducing equipment costs.

[0097] As an optional implementation manner, the first parameter includes a port DC current of the target converter;

[0098] The specific manner in which the processing module determines the current limiting coefficient according to the first parameter includes:

[0099] determining whether the target converter is in a fault state according to the port DC current;

[0100] If the target converter is in a fault state, a current limiting coefficient is obtained by calculation according to the port DC current;

[0101] If the target converter is in a normal state, the DC current at the port of the target converter is continuously detected.

[0102] In this embodiment, the first parameter may include the port DC current of the target converter. Specifically, it can be determined whether the target converter is in a fault state through the situation of the port DC current of the target converter itself and the change of the port DC current over time, and the current limiting control scheme can be triggered when the converter is in a fault state, thereby realizing real-time monitoring and control, and improving the real-time and effectiveness of the control.

[0103] As an optional implementation manner, the specific manner in which the processing module determines whether the target converter is in a fault state according to the port DC current includes:

[0104] According to the port DC current, obtaining a delayed DC current after a fixed delay, and calculating a first difference between the port DC current and the delayed DC current;

[0105] If the first difference is greater than a preset start threshold, it is determined that the target converter is in a fault state, and the first difference is used as a start signal.

[0106] The difference between the port DC current and the DC current after a fixed delay can be used to obtain the change in the current port DC current. Therefore, when the change in the port DC current exceeds the preset start-up threshold, it is determined that there is a fault in the target converter and the corresponding equipment, and current limiting is required to cross the fault, thereby realizing real-time monitoring of the fault and improving the real-time and effectiveness of detection and control.

[0107] As an optional implementation manner, the specific manner in which the processing module calculates the current limiting coefficient according to the port DC current includes:

[0108] According to the start signal, a first frequency domain signal is obtained, and the first frequency domain signal is processed by a preset controller to obtain a second frequency domain signal;

[0109] Obtaining a first time domain signal after inverse Laplace transformation according to the second frequency domain signal;

[0110] A second difference between the start signal and the first time domain signal is calculated, and the second difference is used as a current limiting coefficient.

[0111] By performing Laplace transform on the start signal, a start signal in the frequency domain, i.e., a first frequency domain signal, is obtained, and the start signal in the frequency domain is processed by a controller transfer function to obtain a second frequency domain signal, and the second frequency domain signal is further subjected to an inverse Laplace transform to obtain a corresponding time domain signal, thereby calculating a difference based on the start signal and the processed first time domain signal to obtain a corresponding current limiting coefficient. The current limiting coefficient calculated in this way is directly related to the DC current of the port, thereby improving the effectiveness of control.

[0112] As an optional implementation manner, the second parameter includes the number of operating submodules and a DC voltage reference value of each submodule, and the specific manner in which the processing module determines the second parameter of each of the initial converter submodules according to the current limiting coefficient includes:

[0113] Determining the number of operating submodules according to the product of the current limiting coefficient and the number of initial converter submodules;

[0114] The DC voltage reference value of each submodule in operation is determined according to the product of the current limiting coefficient and the initial value of the DC voltage of each submodule.

[0115] This embodiment determines the number of sub-modules that need to be in operation at present by multiplying the determined current limiting coefficient with the number of initial converter sub-modules, and obtains the current DC voltage reference value of each sub-module by multiplying the current limiting coefficient with the initial value of the bridge arm DC voltage corresponding to each sub-module. Thus, the operating state and operating parameters of each sub-module are specifically controlled, which reduces equipment costs and improves control efficiency while also improving control effectiveness.

[0116] As an optional implementation manner, the initial number of converter submodules on the three-phase circuit of the target converter is consistent, and the operating number of converter submodules on the three-phase circuit of the target converter is consistent.

[0117] In the present application, the target inverter three-phase circuit is configured with the same number of initial inverter sub-modules, and the number of operating inverter sub-modules is ensured to be consistent during the control process, so that the circuit parameters can be kept balanced, thereby improving the stability of the circuit during the control process.

[0118] As an optional implementation, the converter submodule includes a half-bridge converter submodule.

[0119] The converter submodule in the present application may be in the form of a half-bridge converter submodule, which has a simple structure, can reduce structural costs, and is easy to implement the control method in each embodiment.

[0120] It should be noted that it should be understood that the division of the various modules of the above device is only a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or they can be physically separated. And these modules can all be implemented in the form of software called by processing elements; they can also be all implemented in the form of hardware; some modules can also be implemented in the form of software called by processing elements, and some modules can be implemented in the form of hardware. For example, the processing module can be a separately established processing element, or it can be integrated in a chip of the above device. In addition, it can also be stored in the memory of the above device in the form of program code, and called and executed by a processing element of the above device. The function of the above-determined module. The implementation of other modules is similar. In addition, these modules can be fully or partially integrated together, or they can be implemented independently. The processing element here can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each module above can be completed by an integrated logic circuit of hardware in the processor element or instructions in the form of software.

[0121] Indicatively, Figure 5 As shown, Figure 5This is a schematic diagram of the internal structure of a computer device provided in an embodiment of the present application. The computer device 300 may be provided as a server. Figure 5 The computer device 300 includes a processing component 302, which further includes one or more processors, and a memory resource represented by a memory 301 for storing instructions executable by the processing component 302, such as an application. The application stored in the memory 301 may include one or more modules, each corresponding to a set of instructions. In addition, the processing component 302 is configured to execute the instructions to perform the text recognition method of any of the above embodiments.

[0122] The computer device 300 may further include a power supply component 303 configured to perform power management of the computer device 300, a wired or wireless network interface 304 configured to connect the computer device 300 to a network, and an input / output (I / O) interface 305. The computer device 300 may operate based on an operating system stored in the memory 301, such as Windows Server TM, Mac OS X TM, Unix TM, Linux TM, Free BSD TM, or the like.

[0123] Those skilled in the art will understand that Figure 5 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0124] An embodiment of the present application provides a storage medium, in which computer-readable instructions are stored. When the computer-readable instructions are executed by one or more processors, the one or more processors execute a method provided in any embodiment.

[0125] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0126] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can refer to each other.

[0127] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fault ride-through method based on converter control, characterized in that: The method comprises: detecting a first parameter of a target inverter; Wherein, the target converter includes a plurality of initial converter submodules; And, the first parameter is used to indicate the working state of the target converter; Determining a current limiting coefficient according to the first parameter; Determining a second parameter of each of the initial converter submodules according to the current limiting coefficient, and controlling a working state of each of the initial converter submodules according to the second parameter; The working state includes a running state and a disconnected state.

2. The method according to claim 1, characterized in that The first parameter includes a port DC current of the target converter; Determining the current limiting coefficient according to the first parameter includes: determining whether the target converter is in a fault state according to the port DC current; If the target converter is in a fault state, a current limiting coefficient is obtained by calculation according to the port DC current; If the target converter is in a normal state, the DC current at the port of the target converter is continuously detected.

3. The method according to claim 2, characterized in that The step of determining whether the target converter is in a fault state according to the port DC current includes: According to the port DC current, obtaining a delayed DC current after a fixed delay, and calculating a first difference between the port DC current and the delayed DC current; If the first difference is greater than a preset start threshold, it is determined that the target converter is in a fault state, and the first difference is used as a start signal.

4. The method according to claim 3, characterized in that The calculating and obtaining the current limiting coefficient according to the port DC current includes: According to the start signal, a first frequency domain signal is obtained, and the first frequency domain signal is processed by a preset controller to obtain a second frequency domain signal; Obtaining a first time domain signal after inverse Laplace transformation according to the second frequency domain signal; A second difference between the start signal and the first time domain signal is calculated, and the second difference is used as a current limiting coefficient.

5. The method according to claim 4, characterized in that The second parameter includes the number of submodules in operation and a DC voltage reference value of each submodule. The second parameter of each initial converter submodule is determined according to the current limiting coefficient, including: Determining the number of operating submodules according to the product of the current limiting coefficient and the number of initial converter submodules; The DC voltage reference value of each submodule in operation is determined according to the product of the current limiting coefficient and the initial value of the DC voltage of each submodule.

6. The method according to claim 5, characterized in that The initial number of converter submodules on the three-phase circuit of the target converter is consistent, and the operating number of converter submodules on the three-phase circuit of the target converter is consistent.

7. The method according to any one of claims 1 to 6, characterized in that: The converter submodule comprises a half-bridge converter submodule.

8. A fault ride-through device based on converter control, characterized in that: The device comprises: A detection module, used for detecting a first parameter of a target converter; Wherein, the target converter includes a plurality of initial converter submodules; And, the first parameter is used to indicate the working state of the target converter; A processing module, used for determining a current limiting coefficient according to the first parameter; The processing module is further used to determine a second parameter of each of the initial converter submodules according to the current limiting coefficient, and control a working state of each of the initial converter submodules according to the second parameter; The working state includes a running state and a disconnected state.

9. A computer device, characterized in that: The method comprises one or more processors and a memory, wherein the memory stores computer-readable instructions, and when the computer-readable instructions are executed by the one or more processors, the steps of the method according to any one of claims 1 to 7 are performed.

10. A storage medium, characterized in that: The storage medium stores computer-readable instructions, and when the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the method according to any one of claims 1 to 7.

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