Structured electromagnetic transient modeling method and device for direct-driven wind turbine generator

Abstract

The invention discloses a structured electromagnetic transient modeling method and device for a direct-driven wind turbine generator, and belongs to the technical field of new energy power generation, and the method comprises the steps: constructing a common core module and a model differentiation module for a main circuit and a control circuit of the wind turbine generator respectively, determining a converter topological structure and a filter type in a main circuit differentiation module according to the main circuit parameters of the wind turbine generator to be modeled; according to the recovery control process after the fault, determining a recovery control type after the fault in the differential module of the control circuit; and connecting the common core module of the main circuit and the control circuit with the determined converter topological structure, the filter type and the recovery control type after the fault in the electromagnetic transient simulation platform according to a topological block diagram, and generating a complete electromagnetic transient model of the wind turbine generator to be modeled. According to the method, the problems that an existing model is insufficient in precision, poor in universality and low in modeling efficiency are solved, the high-precision unit model can be efficiently generated by constructing the unified and configurable model framework, and high universality is achieved.

Description

Technical Field

[0001] This invention relates to the field of new energy power generation technology, specifically to a structured electromagnetic transient modeling method and apparatus for direct-drive wind turbine generators. Background Technology

[0002] As the proportion of new energy power generation in the power grid continues to increase, its impact on the safety and stability of the power system is becoming increasingly significant. The power system is also placing increasingly stringent requirements on the ability of grid-connected wind turbines to maintain grid-connected operation during grid faults, i.e., their high- and low-voltage fault ride-through capabilities. To accurately analyze the dynamic response characteristics of wind turbines under grid faults and provide a reliable basis for grid planning and safety assessment, establishing an accurate electromagnetic transient simulation model of wind turbines is crucial.

[0003] Existing electromagnetic transient models for wind turbines suffer from two main problems. First, the models do not adequately consider the entire fault ride-through process, resulting in insufficient simulation accuracy. Particularly during the fault recovery phase, the active power recovery strategies of different turbines significantly impact the secondary impacts and frequency stability of the power grid. However, existing models often omit or simplify this process, leading to significant discrepancies between simulation results and actual turbine responses. Second, existing modeling methods suffer from poor versatility and low efficiency. Research typically focuses on modeling single, specific turbine models, lacking a universal modeling method capable of characterizing and accommodating the response characteristics of turbines from various manufacturers and models. When simulating an actual wind farm containing multiple turbine models, it is necessary to develop and debug dedicated models for each model, resulting in a massive workload, low efficiency, and inconvenience for practical engineering applications. While some technical solutions attempt to improve model accuracy by performing phased and mode-specific refined modeling of the fault process of a single turbine, this approach remains limited to optimizing individual dedicated models and does not address the fundamental problems of repetitive modeling for different turbine models and poor versatility. Summary of the Invention

[0004] Based on this, it is necessary to propose a structured electromagnetic transient modeling method and device for direct-drive wind turbines to address the above problems. This aims to solve the technical problems in the existing electromagnetic transient models of wind turbines, which suffer from insufficient accuracy due to incomplete consideration of the fault ride-through process, as well as low modeling efficiency and inconvenience in engineering applications due to a lack of universality.

[0005] This application provides a structured electromagnetic transient modeling method for direct-drive wind turbine generators, the method comprising: The first common core module and the first model differentiated module are constructed for the main circuit of the direct-drive wind turbine. The first common core module includes the wind turbine and the drive train, and the first model differentiated module includes converters with different topologies and filters of different types. The second common core module and the second model differentiated module are used to construct the control circuit of the direct-drive wind turbine. The second common core module includes turbine-side converter control, grid-side converter control, low voltage ride-through control and high voltage ride-through control. The second model differentiated module includes different types of recovery control after a fault. The converter topology and filter type in the first model differentiation module of the direct-drive wind turbine model to be modeled are determined based on the main circuit parameters of the direct-drive wind turbine model to be modeled. The recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled is determined based on the recovery control process after the fault during the entire low-voltage fault ride-through response process. The converter topology and filter type in the first common core module, the first model differentiation module of the direct-drive wind turbine model to be modeled, the second common core module, and the recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled are connected in the electromagnetic transient simulation platform according to the topology block diagram to generate a complete electromagnetic transient model that matches the response characteristics of the direct-drive wind turbine model to be modeled.

[0006] Furthermore, the converters with different topologies include at least two-level topology converters and three-level topology converters, and the filters of different types include at least L-type filters, LC-type filters and LCL-type filters; The converters with different topologies and the filters of different types are distinguished by a first logic flag bit.

[0007] Furthermore, the different types of recovery control after the fault include the instantaneous recovery of active power to the pre-fault steady-state value after the fault is cleared and the slow recovery of active power at a preset slope. When the recovery control type after the fault is the slow recovery of active power at a preset slope, the slope value is synchronously input as a model parameter. The different types of recovery control after a fault are distinguished by a second logic flag.

[0008] Furthermore, when the recovery control type after the fault is active power slowly recovering at a preset slope, the slope value is synchronously input as a model parameter, and the active current reference value is determined according to the following formula:

[0009] In the formula i p_fault Active current during the fault i p Reference value, k1 represents the fault recovery phase during the entire fault ride-through response process. t 2 -t The first recovery slope over time 3. k 2 represents the fault recovery phase of the entire fault ride-through response process. t 3 -t The second recovery slope over time 4.

[0010] Further, the step of connecting the first common core module, the converter topology and filter type in the first model differentiation module of the direct-drive wind turbine model to be modeled, the second common core module, and the post-fault recovery control type in the second model differentiation module of the direct-drive wind turbine model to be modeled in the electromagnetic transient simulation platform according to the topology block diagram to generate a complete electromagnetic transient model that matches the response characteristics of the direct-drive wind turbine model to be modeled includes: The first logic flag parameter value of the first model differentiation module is determined based on the converter topology and filter type in the first model differentiation module of the direct-drive wind turbine to be modeled. The second logic flag parameter value of the second model differentiation module is determined based on the recovery control type after a fault in the second model differentiation module of the direct-drive wind turbine to be modeled. The first common core module, the first model differentiation module, the second common core module, and the second model differentiation module are connected in the electromagnetic transient simulation platform according to the topology diagram. By inputting the first logic flag parameter value and the second logic flag parameter value, a complete electromagnetic transient model matching the response characteristics of the direct-drive wind turbine model to be modeled is generated.

[0011] Furthermore, the low-voltage ride-through control includes: When the grid connection point voltage is in the pre-fault steady-state phase, the q-axis current reference value is... i q * Reactive power is provided by the outer loop; When the grid connection point voltage drops to the low-break-through threshold, the q-axis current reference value... i q * Switch to low voltage ride-through control.

[0012] Furthermore, the high-voltage ride-through control includes: When the grid connection point voltage is in the pre-fault steady-state phase, the q-axis current reference value is... i q * Reactive power is provided by the outer loop; When the grid connection point voltage rises to the high-throughput threshold, the q-axis current reference value is... iq * Switch to high voltage ride-through control.

[0013] This application also provides a structured electromagnetic transient modeling device for direct-drive wind turbine generators, the device comprising: The main circuit construction module is used to construct the first common core module and the first model differentiation module of the main circuit of the direct-drive wind turbine. The first common core module includes the wind turbine and the drive train, and the first model differentiation module includes converters with different topologies and different types of filters. The control circuit construction module is used to construct the second common core module and the second model differentiated module of the control circuit of the direct-drive wind turbine. The second common core module includes turbine-side converter control, grid-side converter control, low voltage ride-through control and high voltage ride-through control. The second model differentiated module includes different types of recovery control after a fault. The main circuit determination module is used to determine the converter topology and filter type in the first model differentiation module of the direct-drive wind turbine model to be modeled based on the main circuit parameters of the direct-drive wind turbine model to be modeled. The control circuit determination module is used to determine the post-fault recovery control type in the second model differentiation module of the direct-drive wind turbine model to be modeled based on the post-fault recovery control process during the entire low-voltage fault ride-through response of the direct-drive wind turbine model to be modeled. The model building module is used to connect the first common core module, the converter topology and filter type in the first model differentiation module of the direct-drive wind turbine model to be modeled, the second common core module and the recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled in the electromagnetic transient simulation platform according to the topology block diagram, and generate a complete electromagnetic transient model that matches the response characteristics of the direct-drive wind turbine model to be modeled.

[0014] This application embodiment also provides a computer device, including a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps: The first common core module and the first model differentiated module are constructed for the main circuit of the direct-drive wind turbine. The first common core module includes the wind turbine and the drive train, and the first model differentiated module includes converters with different topologies and filters of different types. The second common core module and the second model differentiated module are used to construct the control circuit of the direct-drive wind turbine. The second common core module includes turbine-side converter control, grid-side converter control, low voltage ride-through control and high voltage ride-through control. The second model differentiated module includes different types of recovery control after a fault. The converter topology and filter type in the first model differentiation module of the direct-drive wind turbine model to be modeled are determined based on the main circuit parameters of the direct-drive wind turbine model to be modeled. The recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled is determined based on the recovery control process after the fault during the entire low-voltage fault ride-through response process. The converter topology and filter type in the first common core module, the first model differentiation module of the direct-drive wind turbine model to be modeled, the second common core module, and the recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled are connected in the electromagnetic transient simulation platform according to the topology block diagram to generate a complete electromagnetic transient model that matches the response characteristics of the direct-drive wind turbine model to be modeled.

[0015] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the following steps: The first common core module and the first model differentiated module are constructed for the main circuit of the direct-drive wind turbine. The first common core module includes the wind turbine and the drive train, and the first model differentiated module includes converters with different topologies and filters of different types. The second common core module and the second model differentiated module are used to construct the control circuit of the direct-drive wind turbine. The second common core module includes turbine-side converter control, grid-side converter control, low voltage ride-through control and high voltage ride-through control. The second model differentiated module includes different types of recovery control after a fault. The converter topology and filter type in the first model differentiation module of the direct-drive wind turbine model to be modeled are determined based on the main circuit parameters of the direct-drive wind turbine model to be modeled. The recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled is determined based on the recovery control process after the fault during the entire low-voltage fault ride-through response process. The converter topology and filter type in the first common core module, the first model differentiation module of the direct-drive wind turbine model to be modeled, the second common core module, and the recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled are connected in the electromagnetic transient simulation platform according to the topology block diagram to generate a complete electromagnetic transient model that matches the response characteristics of the direct-drive wind turbine model to be modeled.

[0016] The embodiments of this application have the following beneficial effects: By constructing a unified structured model that includes a common core module and configurable model-differentiated modules, this application overcomes the drawback of traditional methods that require separate modeling for each model of turbine. Users only need to adjust the configuration parameters to efficiently generate simulation models of different models of turbines, which greatly improves modeling efficiency and model versatility. This facilitates engineering applications in complex scenarios such as large wind farms containing multiple models of turbines, and can efficiently and accurately simulate the fault ride-through characteristics of different models of turbines, significantly improving the applicability of modeling. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] in: Figure 1 This is a flowchart illustrating a structured electromagnetic transient modeling method for a direct-drive wind turbine in one embodiment. Figure 2 This is a topology diagram of a direct-drive wind turbine in one embodiment; Figure 3a This is a diagram showing the fault ride-through response test results of Unit 1 in one embodiment; Figure 3b This is a diagram showing the fault ride-through response test results of Unit 2 in one embodiment; Figure 4 This is a schematic diagram of the entire low-voltage fault ride-through response process of a direct-drive wind turbine in one embodiment. Figure 5 This is a general control block diagram for a direct-drive wind turbine in one embodiment; Figure 6 This is a diagram illustrating the recovery process of active power at a certain recovery rate in one embodiment. Figure 7 Here is a low-voltage breakdown control logic diagram for one embodiment; Figure 8Here is a high-voltage surge control logic diagram for one embodiment; Figure 9 A structural diagram of a structured electromagnetic transient modeling device for a direct-drive wind turbine in one embodiment; Figure 10 Here is a block diagram of the machine-side converter control in one embodiment; Figure 11 Here is a block diagram of the grid-side converter control in one embodiment; Figure 12 This is a comparison chart of the response of three-phase high wind and 20% voltage drop in one embodiment. Figure 13 This is a bar chart showing the response error of three-phase high wind and 20% voltage drop in one embodiment. Figure 14 This is a comparison chart of the response to a two-phase strong wind and a 20% voltage drop in one embodiment. Figure 15 This is a bar chart showing the response error under two-phase strong wind and 20% voltage drop conditions in one embodiment. Figure 16 This is a comparison chart of the response of three-phase small wind and voltage drop of 20% in one embodiment. Figure 17 This is a bar chart showing the response error of a three-phase system under low wind and 20% voltage drop conditions in one embodiment. Figure 18 This is a comparison chart of the response under two-phase low wind and 20% voltage drop conditions in one embodiment. Figure 19 This is a bar chart showing the response error under a two-phase low wind and 20% voltage drop condition in one embodiment. Figure 20 This is a schematic diagram of the structure of a computer device in one embodiment; Figure 21 This is a schematic diagram of the structure of a computer-readable storage medium in one embodiment. Detailed Implementation

[0019] The technical solutions of 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 of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0020] This application conducts fault ride-through response characteristic tests on "black box" models or controllers of different types of direct-drive wind turbines in accordance with the national standard GB_T 19963-2021 "Technical Regulations for Wind Farm Connection to Power Systems": Specifically, the topology of a direct-drive wind turbine is as follows: Figure 2As shown, a direct-drive wind turbine mainly consists of a mechanical transmission model, a permanent magnet synchronous generator, a turbine-side converter, a grid-side converter, a turbine-side converter control circuit, a grid-side filter, a step-up transformer, and the power grid. The mechanical transmission model typically employs mathematical models such as wind turbine aerodynamics. The permanent magnet synchronous generator has a relatively mature encapsulated model. Power electronic devices such as the turbine-grid converter, grid-side filter, and turbine-grid converter control circuit are crucial for electromagnetic transient modeling. The following section uses two models of direct-drive wind turbines as examples to conduct fault ride-through response characteristic tests on the "black box" models of these two models according to the standard GB_T19963-2021 "Technical Regulations for Wind Farm Access to Power Systems." Some of the test curves obtained are shown below. Figure 3a and Figure 3b As shown, comparison Figure 3a and Figure 3b The response characteristics of different models of direct-drive wind turbines under different voltage drop levels revealed that their commonalities are mainly reflected in the fact that the response process during the full simulation time is basically the same, while the differences are mainly reflected in the differences in the transient response morphology and the steady-state current generation strategy during the fault period of different models of direct-drive turbines.

[0021] The entire process of low-voltage fault ride-through response for direct-drive wind turbines is as follows: Figure 4 As shown, Figure 4 The entire response process was divided into four stages: the pre-fault steady state, the fault transient state, the fault steady state, and the fault recovery process. 0-t0 represents the pre-fault steady state, where the response characteristics are controlled by the converter's steady-state control strategy, typically including an active power outer loop, a voltage outer loop, and a current inner loop. t0-t1 represents the fault-causing transient state, during which the voltage amplitude begins to drop. Before reaching the undervoltage threshold, the response is controlled by the steady-state control strategy. Upon reaching the undervoltage threshold, the control strategy switches, causing a step change in the current inner loop reference value. The response exhibits a transient process under the combined effect of voltage changes and control strategy switching. t1-t2 represents the steady state during the fault, where the response characteristics are controlled by the converter's fault ride-through control strategy, and the reactive current is given by a specific calculation strategy. t2-t4 represents the fault recovery period. At time t2, the short-circuit fault is cleared. The fault recovery phase is divided into two types: sloped recovery and non-sloped recovery. Non-sloped recovery instantaneously returns to the pre-fault level; when the voltage recovers to the threshold, the control strategy switches to steady-state control. Sloped recovery slowly increases at a certain recovery rate until the voltage returns to the normal pre-fault level.

[0022] Based on the analysis of the entire fault ride-through response characteristics of direct-drive wind turbines, it can be concluded that the commonality in the responses of different turbine models mainly stems from the universality of the core control framework and switching process. Specifically, a steady-state control strategy is used before and after fault ride-through, and a fault ride-through control strategy is switched to after the fault ride-through occurs. The general control block diagram is as follows: Figure 5 As shown. The differences in response between different models of wind turbines mainly stem from the different styles and characteristics of the detailed control structures within the steady-state control strategy and fault ride-through control strategy of different manufacturers. Therefore, the common core modules of the main circuit of direct-drive wind turbines include: wind turbine and drive train; the model-differentiated modules of the main circuit include: converters with different topologies and different types of filters; the common core modules of the control circuit of direct-drive wind turbines include: turbine-side converter control, grid-side converter control, low-voltage ride-through control, and high-voltage ride-through control; the model-differentiated modules of the control circuit include: post-fault recovery control.

[0023] This application provides a structured electromagnetic transient modeling method for direct-drive wind turbine generators. Please refer to [link to relevant documentation]. Figure 1 , Figure 1 This is a flowchart illustrating a structured electromagnetic transient modeling method for a direct-drive wind turbine in one embodiment; the structured electromagnetic transient modeling method for a direct-drive wind turbine includes steps S1 to S5.

[0024] Step S1: Construct the first common core module and the first model-differentiated module of the main circuit of the direct-drive wind turbine. The first common core module includes the wind turbine and the drive train. The first model-differentiated module includes converters with different topologies and filters of different types. In some embodiments, the converters with different topologies include at least two-level topology converters and three-level topology converters, and the filters of different types include at least L-type filters, LC-type filters and LCL-type filters; The converters with different topologies and the filters of different types are distinguished by a first logic flag bit.

[0025] Specifically, the first model differentiation module implements the following topology switching through the first logic flag bit, for example: When the converter topology flag is 0, a two-level topology converter is used; When the converter topology flag = 1, a three-level topology converter is used; When the filter type flag is 0, 1, or 2, it corresponds to L-type, LC-type, and LCL-type filters, respectively.

[0026] Step S2: Construct a second common core module and a second model differentiated module for the control circuit of a direct-drive wind turbine. The second common core module includes turbine-side converter control, grid-side converter control, low-voltage ride-through control, and high-voltage ride-through control. The second model differentiated module includes different types of recovery control after a fault. In some implementations, the different types of recovery control after a fault include the instantaneous recovery of active power to the pre-fault steady-state value after the fault is cleared and the slow recovery of active power at a preset slope. When the recovery control type after a fault is the slow recovery of active power at a preset slope, the slope value is synchronously input as a model parameter. The different types of recovery control after a fault are distinguished by a second logic flag.

[0027] Specifically, when the recovery control flag is 0, the active power instantly recovers to the steady-state value before the fault after the fault is cleared. When the recovery control flag is 1, the active power recovers slowly at the set slope, and the slope value is used as the input of the model parameters.

[0028] In some implementations, when the post-fault recovery control type is active power slowly recovering at a preset slope, the slope value is synchronously input as a model parameter, and the active current reference value is determined according to the following formula:

[0029] In the formula i p_fault Active current during the fault i p Reference value, k 1 represents the fault recovery phase during the entire fault ride-through response process. t 2 -t The first recovery slope over time 3. k 2 represents the fault recovery phase of the entire fault ride-through response process. t 3 -t The second recovery slope over time 4.

[0030] Specifically, when the recovery control type after the fault is active power slowly recovering at a preset slope, see [reference needed]. Figure 6 The diagram shown illustrates the recovery process of active power being restored at a certain recovery rate in one embodiment.

[0031] In some implementations, the low-voltage ride-through control includes: When the grid connection point voltage is in the pre-fault steady-state phase, the q-axis current reference value is... i q * Reactive power is provided by the outer loop; When the grid connection point voltage drops to the low-break-through threshold, the q-axis current reference value... i q * Switch to low voltage ride-through control.

[0032] Specifically, when a voltage fault occurs in the power grid, the wind turbine needs to generate or absorb a certain amount of reactive power and limit the output of active power if necessary, depending on the severity of the voltage drop or rise.

[0033] analyze Figure 4 It is known that when a wind turbine is operating in the pre-fault steady-state phase, the reactive power injected into the grid is generally maintained at around 0. The active power operates under steady-state control strategies such as speed control, maximum power point tracking (MPPT), and power control, depending on the wind speed. When a short-circuit fault occurs in the grid, the wind turbine detects that the system voltage has dropped below a threshold and switches to low-voltage ride-through (LVRT) control logic. According to my country's grid connection standards, after a LVRT fault occurs, the wind turbine needs to have the ability to inject reactive current into the grid to support grid voltage recovery. The reactive current needs to be adjusted according to the voltage drop depth.

[0034] In the formula This is a reference value for reactive current during a fault. The reactive power support factor for low voltage ride-through; , The reactive voltage threshold; This is the rated current of the unit.

[0035] According to my country's grid connection standards, the values ​​of the above formula can be:

[0036] To ensure that wind turbines can effectively generate reactive power to support grid voltage during faults, most mainstream turbines adopt reactive power priority control, meaning that active current is limited by reactive current output.

[0037] Based on the above analysis, the low-voltage ride-through control logic can be obtained as follows: Figure 7 As shown, when the grid connection point voltage is in steady state before the fault, the q-axis current reference value is... i q * Provided by the reactive power outer loop, when the grid connection point voltage drops to the low-breakdown threshold, i q * Switch to low-voltage ride-through control, as required by the grid connection standard, as shown in the first fault dashed box in the figure. When the grid connection point voltage recovers to the low-voltage ride-through exit threshold... i q* Switch back to being provided by the reactive power outer loop; when the grid connection point voltage is in steady state before the fault, the d-axis current reference value id* is provided by the active power outer loop; when the grid connection point voltage drops to the low-breakdown threshold... i d * Switch to low-voltage ride-through control, based on the reactive power priority control principle, as shown in the second fault dashed box in the figure. When the grid connection point voltage begins to recover but has not yet recovered to the exit low-voltage ride-through threshold... i d * Switch to the recovery process. For detailed control logic, see the post-fault recovery control section. When the grid connection point voltage recovers to the exit low-voltage threshold... i d * Switch back to being provided by the active power outer loop. The low-voltage fault control logic allows the simulation model's response characteristics during the transient process from the occurrence of a low-voltage fault to fault recovery to better match the measured response, and is one of the key structures for establishing a more accurate structured electromagnetic transient model.

[0038] In some implementations, the high-voltage ride-through control includes: When the grid connection point voltage is in the pre-fault steady-state phase, the q-axis current reference value is... i q * Reactive power is provided by the outer loop; When the grid connection point voltage rises to the high-throughput threshold, the q-axis current reference value is... i q * Switch to high voltage ride-through control.

[0039] Specifically, during the pre-fault steady-state operation of wind turbines, the reactive power injected into the grid is generally maintained at around 0, while the active power operates under steady-state control strategies such as speed control, maximum power point tracking (MPPT), and power control, depending on the wind speed. When a high-voltage fault occurs in the grid, the wind turbine detects that the system voltage has risen above a threshold and switches to high-voltage ride-through control logic. According to my country's grid connection standards, after a high-voltage ride-through fault occurs, the wind turbine needs to absorb reactive current from the grid to reduce the impact of the voltage rise. The reactive current needs to be adjusted according to the degree of voltage rise.

[0040] In the formula, This is a reference value for reactive current during a fault. The high-voltage ride-through reactive power support factor is determined by the grid connection standard. The rated current of the generator unit and the active power generally do not change during a fault, maintaining the control logic in steady state. When the grid short-circuit fault is cleared and the voltage returns to normal, the active and reactive power instantly return to steady-state levels after the fault is cleared.

[0041] Based on the above analysis, the high-voltage fault control logic can be obtained as follows: Figure 8 As shown, when the grid connection point voltage is in steady state before the fault, the q-axis current reference value is... i q * Power is supplied by the outer reactive power loop. When the grid connection point voltage rises to the high-voltage threshold, i q * Switch to high-voltage ride-through control, as required by the grid connection standard, as shown in the first fault dashed box in the figure. When the grid connection point voltage recovers to the exit high-voltage ride-through threshold... i q * Switch back to reactive power supplied by the outer loop; when the grid connection point voltage is in steady state before the fault, the d-axis current reference value... i d * Provided by the active power outer loop, when the grid connection point voltage rises to the high-throughput threshold, i d * The control remains unchanged during steady state, and then the voltage recovery process continues. i d * The control remains unchanged throughout the steady-state process. The high-penetration fault control logic allows the simulation model's response characteristics during the transient process from the occurrence of a high-penetration fault to the fault recovery process to better match the measured response, and is one of the key structures for establishing a more accurate structured electromagnetic transient model.

[0042] Step S3: Determine the converter topology and filter type in the first model differentiation module of the direct-drive wind turbine model to be modeled based on the main circuit parameters of the direct-drive wind turbine model to be modeled. Specifically, the converter topology and filter type are queried from the main circuit parameters in the instruction manual of the direct-drive wind turbine model to be modeled.

[0043] Step S4: Determine the recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled based on the recovery control process after the fault during the low-voltage fault ride-through response of the direct-drive wind turbine model to be modeled. Specifically, low-voltage fault ride-through tests were conducted on the direct-drive wind turbine model to be modeled, and the recovery control process after the fault was carried out throughout the low-voltage fault ride-through response.

[0044] Step S5: Connect the first common core module, the converter topology and filter type in the first model differentiation module of the direct-drive wind turbine to be modeled, the second common core module and the recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine to be modeled in the electromagnetic transient simulation platform according to the topology block diagram to generate a complete electromagnetic transient model that matches the response characteristics of the direct-drive wind turbine to be modeled. In some implementations, the step of connecting the first common core module, the converter topology and filter type in the first model differentiation module of the direct-drive wind turbine to be modeled, the second common core module, and the post-fault recovery control type in the second model differentiation module of the direct-drive wind turbine to be modeled in the electromagnetic transient simulation platform according to the topology block diagram to generate a complete electromagnetic transient model that matches the response characteristics of the direct-drive wind turbine to be modeled includes: The first logic flag parameter value of the first model differentiation module is determined based on the converter topology and filter type in the first model differentiation module of the direct-drive wind turbine to be modeled. Specifically, for example, by querying the main circuit parameters of the instruction manual of the direct-drive wind turbine model to be modeled, it is determined that the converter topology is a two-level topology converter and the filter type is an LCL filter. Then, the first logic flag parameter value of the first model differentiation module is converter topology flag = 0 and filter type flag = 2.

[0045] The second logic flag parameter value of the second model differentiation module is determined based on the recovery control type after a fault in the second model differentiation module of the direct-drive wind turbine to be modeled. Specifically, for example, when performing a low-voltage fault ride-through test on a direct-drive wind turbine of the model to be modeled, if the recovery control process after the fault during the entire low-voltage fault ride-through response is such that the active power recovers instantaneously to the pre-fault steady-state value after the fault is cleared, then the second logic flag parameter value is recovery control flag = 0. If the active power recovers slowly at a set slope, then the second logic flag parameter value is recovery control flag = 1. Simultaneously, the fault recovery phase during the entire fault ride-through response is input. t 2 -t First recovery slope at time 3 k 1. The fault recovery phase of the entire fault-crossing response process t 3 -t Second recovery slope at time 4 k 2.

[0046] The first common core module, the first model differentiation module, the second common core module, and the second model differentiation module are connected in the electromagnetic transient simulation platform according to the topology diagram. By inputting the first logic flag parameter value and the second logic flag parameter value, a complete electromagnetic transient model matching the response characteristics of the direct-drive wind turbine model to be modeled is generated.

[0047] Specifically, physical switches are used to connect the various modules according to a structured control block diagram.

[0048] By employing the technical solution of this embodiment, this application successfully constructs a unified and configurable model framework through the core idea of ​​"analysis-deconstruction-combination". This framework can not only accurately reproduce the complete fault ride-through process, including the fault recovery phase, thus ensuring the high accuracy of the model; but also simulate various types of wind turbines with different hardware and control strategies through simple parameter configuration, greatly improving modeling efficiency and model versatility, and providing an effective technical approach to solving the simulation modeling challenges in complex scenarios such as large-scale hybrid wind farms.

[0049] In this application embodiment, a structured electromagnetic transient modeling device for direct-drive wind turbine generators is provided. Please refer to [link to relevant documentation]. Figure 9 , Figure 9 This is a structural diagram of a structured electromagnetic transient modeling device for a direct-drive wind turbine in one embodiment. The structured electromagnetic transient modeling device for the direct-drive wind turbine includes: a main circuit construction module 201, a control circuit construction module 202, a main circuit determination module 203, a control circuit determination module 204, and a model construction module 205.

[0050] Among them, the main circuit construction module 201 is used to construct the first common core module and the first model differentiation module of the main circuit of the direct-drive wind turbine. The first common core module includes the wind turbine and the transmission chain, and the first model differentiation module includes converters with different topologies and filters of different types. The control circuit construction module 202 is used to construct a second common core module and a second model differentiation module for the control circuit of a direct-drive wind turbine. The second common core module includes turbine-side converter control, grid-side converter control, low-voltage ride-through control and high-voltage ride-through control. The second model differentiation module includes different types of recovery control after a fault. The main circuit determination module 203 is used to determine the converter topology and filter type in the first model differentiation module of the direct-drive wind turbine model to be modeled based on the main circuit parameters of the direct-drive wind turbine model to be modeled. The control circuit determination module 204 is used to determine the post-fault recovery control type in the second model differentiation module of the direct-drive wind turbine model to be modeled based on the post-fault recovery control process during the entire low-voltage fault ride-through response of the direct-drive wind turbine model to be modeled. The model building module 205 is used to connect the first common core module, the converter topology and filter type in the first model differentiation module of the direct-drive wind turbine to be modeled, the second common core module and the recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine to be modeled in the electromagnetic transient simulation platform according to the topology block diagram, and generate a complete electromagnetic transient model that matches the response characteristics of the direct-drive wind turbine to be modeled.

[0051] Specifically, for the control of the machine-side converter, please refer to [link / reference]. Figure 10 For grid-side converter control, please refer to [link / reference]. Figure 11 .

[0052] For further details on how each unit in the structured electromagnetic transient modeling device for direct-drive wind turbines implements the above-mentioned technical solution, please refer to the description in the structured electromagnetic transient modeling method for direct-drive wind turbines provided above, which will not be repeated here.

[0053] Finally, the structured electromagnetic transient modeling of the direct-drive wind turbine was verified.

[0054] The model response established using the method proposed in this invention and the measured response of the manufacturer's black-box model are compared with the responses under the following four conditions: three-phase high wind and 20% voltage drop; three-phase low wind and 20% voltage drop; two-phase high wind and 20% voltage drop; and two-phase low wind and 20% voltage drop. The comparison charts and error bar charts are as follows: Figures 12 to 19 As shown in the error comparison chart, yellow represents the maximum error specified by the standard, and cyan represents the error between the manufacturer's black box model and the simulation model.

[0055] comprehensive Figures 12 to 19 It can be seen that the fault ride-through response of the structured electromagnetic transient model of the direct-drive wind turbine established by the structured electromagnetic transient modeling method of this application is basically consistent with the test results of the manufacturer's black box model, and the error is significantly lower than the error specified in the standard, which proves the effectiveness of the modeling method proposed in this application.

[0056] In this application embodiment, a computer device is provided; please refer to... Figure 20 , Figure 20 The diagram below illustrates the structure of a computer device in one embodiment. The device includes a memory 301 and a processor 302. The memory 301 stores a computer program. When the computer program is executed by the processor 302, the processor 302 performs the following steps: The first common core module and the first model differentiated module are constructed for the main circuit of the direct-drive wind turbine. The first common core module includes the wind turbine and the drive train, and the first model differentiated module includes converters with different topologies and filters of different types. The second common core module and the second model differentiated module are used to construct the control circuit of the direct-drive wind turbine. The second common core module includes turbine-side converter control, grid-side converter control, low voltage ride-through control and high voltage ride-through control. The second model differentiated module includes different types of recovery control after a fault. The converter topology and filter type in the first model differentiation module of the direct-drive wind turbine model to be modeled are determined based on the main circuit parameters of the direct-drive wind turbine model to be modeled. The recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled is determined based on the recovery control process after the fault during the entire low-voltage fault ride-through response process. The converter topology and filter type in the first common core module, the first model differentiation module of the direct-drive wind turbine model to be modeled, the second common core module, and the recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled are connected in the electromagnetic transient simulation platform according to the topology block diagram to generate a complete electromagnetic transient model that matches the response characteristics of the direct-drive wind turbine model to be modeled.

[0057] The processor 302 can also be called a CPU (Central Processing Unit). The processor 302 may be an integrated circuit chip with signal processing capabilities. The processor 302 can also be a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor, or the processor 302 can be any conventional processor.

[0058] In this application embodiment, a computer-readable storage medium is provided; please refer to [link to relevant documentation]. Figure 21 , Figure 21This is a schematic diagram of the structure of a computer-readable storage medium in one embodiment, on which a readable computer program 401 is stored; wherein, the computer program 401 may be stored in the storage medium in the form of a software product, including a number of instructions to cause a computer device (which may be a personal computer, a server machine, or a network device, etc.) or a processor to perform the following steps: The first common core module and the first model differentiated module are constructed for the main circuit of the direct-drive wind turbine. The first common core module includes the wind turbine and the drive train, and the first model differentiated module includes converters with different topologies and filters of different types. The second common core module and the second model differentiated module are used to construct the control circuit of the direct-drive wind turbine. The second common core module includes turbine-side converter control, grid-side converter control, low voltage ride-through control and high voltage ride-through control. The second model differentiated module includes different types of recovery control after a fault. The converter topology and filter type in the first model differentiation module of the direct-drive wind turbine model to be modeled are determined based on the main circuit parameters of the direct-drive wind turbine model to be modeled. The recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled is determined based on the recovery control process after the fault during the entire low-voltage fault ride-through response process. The converter topology and filter type in the first common core module, the first model differentiation module of the direct-drive wind turbine model to be modeled, the second common core module, and the recovery control type after the fault in the second model differentiation module of the direct-drive wind turbine model to be modeled are connected in the electromagnetic transient simulation platform according to the topology block diagram to generate a complete electromagnetic transient model that matches the response characteristics of the direct-drive wind turbine model to be modeled.

[0059] The aforementioned storage media include: USB flash drives, portable hard drives, magnetic disks or optical disks, ROM (Read-Only Memory), RAM (Random Access Memory), and other media that can store program code, or terminal devices such as computers, servers, mobile phones, and tablets.

[0060] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0061] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method of structured electromagnetic transient modeling of a direct drive wind turbine, characterized in that, Comprise; The first common core module and the first model differentiation module of the direct drive type wind turbine main circuit are constructed, the first common core module comprises a wind turbine and a transmission chain, and the first model differentiation module comprises a converter with different topological structures and a filter with different types; The second common core module and the second model differentiation module of the direct drive type wind turbine control circuit are constructed, the second common core module comprises a machine side converter control, a grid side converter control, a low voltage ride through control and a high voltage ride through control, and the second model differentiation module comprises different types of recovery controls after a fault; The converter topological structure and the filter type in the first model differentiation module of the direct drive type wind turbine to be built are determined according to the main circuit parameters of the direct drive type wind turbine to be built; The recovery control type after a fault in the second model differentiation module of the direct drive type wind turbine to be built is determined according to the recovery control process after a fault in the whole process of low voltage fault ride through response of the direct drive type wind turbine to be built; The first common core module, the converter topological structure and the filter type in the first model differentiation module of the direct drive type wind turbine to be built, the second common core module and the recovery control type after a fault in the second model differentiation module of the direct drive type wind turbine to be built are connected in a topological block diagram in an electromagnetic transient simulation platform, and a complete electromagnetic transient model matched with the response characteristics of the direct drive type wind turbine to be built is generated.

2. The structured electromagnetic transient modeling method of a direct- driven wind turbine generator according to claim 1, wherein, The converter with different topological structures at least comprises a two-level topological converter and a three-level topological converter, and the filter with different types at least comprises an L-type filter, an LC-type filter and an LCL-type filter; The converter with different topological structures and the filter with different types are distinguished by a first logical flag bit.

3. The structured electromagnetic transient modeling method of a direct- driven wind turbine generator according to claim 1, wherein, The different types of recovery controls after a fault include that active power is instantaneously restored to a steady state value before a fault after a fault is removed and that active power is slowly restored at a preset slope, when the recovery control type after a fault is that active power is slowly restored at a preset slope, the slope value is input as a model parameter synchronously; The different types of recovery controls after a fault are distinguished by a second logical flag bit.

4. The structured electromagnetic transient modeling method of a direct- driven wind turbine generator according to claim 1, wherein, When the recovery control type after a fault is that active power is slowly restored at a preset slope, the slope value is input as a model parameter synchronously, and an active current reference value is determined according to the following formula: wherein i p_fault is a reference value for the active current during a fault, i p is a reference value for the active current during a fault, k 1is a first recovery slope for a time period of a fault recovery phase of the overall fault ride-through response, t 2 -t 3time period of the fault recovery phase of the overall fault ride-through response, k 2is a second recovery slope for a time period of a fault recovery phase of the overall fault ride-through response, t 3 -t 4time period of the fault recovery phase of the overall fault ride-through response.

5. The structured electromagnetic transient modeling method of a direct- driven wind turbine generator according to claim 1, wherein, The first common core module, the converter topological structure and the filter type in the first model differentiation module of the direct drive type wind turbine to be built, the second common core module and the recovery control type after a fault in the second model differentiation module of the direct drive type wind turbine to be built are connected in a topological block diagram in an electromagnetic transient simulation platform, and a complete electromagnetic transient model matched with the response characteristics of the direct drive type wind turbine to be built is generated, comprising: The first logical flag bit parameter value of the first model differentiation module is determined according to the converter topological structure and the filter type in the first model differentiation module of the direct drive type wind turbine to be built; According to the second type differentiation module of the to-be-built model number direct-driven wind turbine after a fault, a second logic flag parameter value of the second type differentiation module is determined according to a recovery control type after the fault; The first common core module, the first type differentiation module, the second common core module and the second type differentiation module are connected in a topology block diagram in an electromagnetic transient simulation platform, and a complete electromagnetic transient model matched with the response characteristics of the to-be-built model number direct-driven wind turbine is generated by inputting the first logic flag parameter value and the second logic flag parameter value.

6. The structured electromagnetic transient modeling method of a direct- driven wind turbine generator according to claim 3, wherein, The low voltage ride through control comprises: When the grid-connected point voltage is in the steady state phase before the fault, the q-axis current reference value i q * is provided by the reactive power outer loop; When the grid point voltage drops to enter the low penetration threshold, the q-axis current reference value i q * Switch to low voltage penetration control.

7. The structured electromagnetic transient modeling method of a direct- driven wind turbine generator according to claim 3, wherein, The high voltage ride through control comprises: When the grid-connected point voltage is in the steady state phase before the fault, the q-axis current reference value i q * is provided by the reactive power outer loop; When the grid point voltage rises to enter the high penetration threshold, the q-axis current reference value i q * Switch to high voltage penetration control.

8. A structured electromagnetic transient modeling apparatus for a direct drive wind turbine generator, comprising: The low voltage ride through control comprises: A main circuit construction module is configured to construct a first common core module and a first type differentiation module of a main circuit of a direct-driven wind turbine, the first common core module comprising a wind turbine and a transmission chain, and the first type differentiation module comprising a converter of different topologies and a filter of different types. A control circuit construction module is configured to construct a second common core module and a second type differentiation module of a control circuit of the direct-driven wind turbine, the second common core module comprising a machine-side converter control, a grid-side converter control, a low voltage ride through control and a high voltage ride through control, and the second type differentiation module comprising different types of recovery controls after a fault. A main circuit determination module is configured to determine a converter topology and a filter type in the first type differentiation module of the to-be-built model number direct-driven wind turbine according to main circuit parameters of the to-be-built model number direct-driven wind turbine. A control circuit determination module is configured to determine a recovery control type after a fault in the second type differentiation module of the to-be-built model number direct-driven wind turbine according to a recovery control process after a fault in a low voltage fault ride through response process of the to-be-built model number direct-driven wind turbine. A model construction module is configured to connect the first common core module, the converter topology and the filter type in the first type differentiation module of the to-be-built model number direct-driven wind turbine, the second common core module and the recovery control type after a fault in the second type differentiation module of the to-be-built model number direct-driven wind turbine in a topology block diagram in an electromagnetic transient simulation platform, and generate a complete electromagnetic transient model matched with the response characteristics of the to-be-built model number direct-driven wind turbine.

9. A computer device, comprising: The computer program is stored in the memory and executed by the processor, so that the processor executes the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer program is stored in the memory and executed by the processor, so that the processor executes the steps of the method according to any one of claims 1 to 7.

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