Fan network-related performance hardware-in-loop test system combined with real-time simulation of power grid environment

Abstract

The invention relates to a wind turbine grid-related performance hardware-in-the-loop test system combined with real-time simulation of a power grid environment, which comprises a wind turbine test system simulation module connected with an offshore wind turbine generator and a power supply grid simulation device, the simulation device is used for simulating the running state of wind turbine generator network-related performance test system hardware jointly formed by an offshore wind turbine generator and a power supply network simulation device; the real power grid simulation module of the power access area is used for simulating electrical characteristics of a real power grid of the access area after the wind turbine generator to be tested is actually put into operation; the wind turbine generator controller is used for sending a driving signal to the wind power converter and sampling voltage and current information of direct current, input and output ends of the converter for closed-loop control and signal modulation; and the power supply grid simulation device controller is used for sending a driving signal to the power supply grid simulation device and sampling voltage and current information of the direct current, the input end and the output end of the power supply grid simulation device converter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power grid simulation, in particular to a wind turbine grid-connected performance hardware-in-the-loop test system for real-time simulation of a joint power grid environment. BACKGROUND

[0002] With the large-scale grid connection of offshore wind power, the grid-connected performance of wind turbines has become a key factor affecting the safe and stable operation of power grids. Wind turbines need to have good fault ride-through capability, power regulation capability and grid adaptability, so their grid-connected performance must be fully verified before grid connection.

[0003] Currently, there are mainly two methods for testing the grid-connected performance of wind turbines: one is to directly connect the unit to the real power grid for on-site testing, and the other is to use traditional power grid simulation devices for laboratory testing. However, direct grid connection testing has significant limitations: offshore wind farm grid connection testing is costly and complex to operate, and the test process may cause unpredictable impact on the power grid, especially fault ride-through testing, which may cause power grid transient disturbance. However, traditional power grid simulation devices mostly use ideal voltage sources or simple impedance simulation, which cannot accurately reproduce the complex impedance characteristics, dynamic response and fault characteristics of the real power grid, resulting in deviations between test results and actual conditions.

[0004] To enable the power grid simulation device to accurately simulate the complex characteristics of the real power grid, a real-time simulation module of a real simulation power grid environment is added, and the voltage of the real grid connection point of the wind turbine in the real-time simulation module of the real power grid is transmitted to the controller of the power grid simulation device, so that the power grid simulator can simulate the output characteristics of the real power grid in real time, and through the communication between the real-time simulation module of the real simulation power grid environment and the wind turbine grid-connected performance test system, the interaction between the unit and the real power grid is simulated.

[0005] However, due to high cost and the fact that this concept has not been applied, there is currently no hardware of such a wind turbine grid-connected performance test system with a combined power grid simulation device and a real-time simulation module of a real power grid environment built and put into operation. The simulation accuracy of the grid characteristics of the above-mentioned wind turbine grid-connected performance test system with a combined power grid simulation device and a real-time simulation module of a real power grid environment is affected by communication delay, power grid simulation device hardware topology, control and modulation algorithms, but since there is no actual hardware platform built, there is still a lack of analysis results of the above-mentioned effects, making it difficult to guide the design of the communication system and the power grid simulation device control system.

[0006] Therefore, it is necessary to propose a hardware-in-the-loop simulation test scheme for the wind turbine grid connection performance test system, which combines a combined grid simulation device and a real-time simulation module of the real grid environment. This scheme allows for the verification and optimization of the control and communication components of the test system at a low cost, high efficiency, high accuracy, and high reliability, without having to build the entire test platform hardware during the design phase. It also verifies and optimizes the real grid model building method and numerical solution algorithm in the real-time simulation module of the real grid. In this scheme, the controllers for the wind turbine and the grid simulation device are actual controllers, but the hardware of the wind turbine and the grid simulation device is built into a real-time simulation module to simulate the behavior of the grid connection test system hardware in real time. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention proposes a hardware-in-the-loop test system for wind turbine grid-connected performance based on real-time simulation of the power grid environment.

[0008] The technical solution of the present invention is as follows: On the one hand, this invention proposes a hardware-in-the-loop test system for wind turbine grid connection performance based on real-time simulation of the power grid environment, comprising: The simulation module of the wind turbine test system, which connects the offshore wind turbine to the power grid simulation device, is used to simulate the operating status of the hardware of the wind turbine grid-connected performance test system, which is composed of the offshore wind turbine and the power grid simulation device. The real power grid simulation module for the power access area is used to simulate the electrical characteristics of the real power grid in the area after the wind turbine under test is actually put into operation; The wind turbine controller is used to send drive signals to the wind power converter and sample the voltage and current information of the DC, input and output terminals of the converter for closed-loop control and signal modulation. The power grid simulation device controller is used to send drive signals to the power grid simulation device and sample the voltage and current information of the DC, input and output terminals of the power grid simulation device converter. The current signal communication module encapsulates the three-phase current data of the test grid connection point in the wind turbine test system simulation module into communication frames and transmits them to the real power grid simulation module for decoding and application. The voltage signal feedback module encapsulates the three-phase voltage data of the actual grid connection point in the real power grid simulation module into communication frames, and transmits them to the controller of the power grid simulation device. After decoding, the data serves as the control reference value for the output voltage of the power grid simulation device.

[0009] In a preferred embodiment, the wind turbine generator set in the simulation module of the wind turbine test system includes a wind turbine mechanical power calculation unit, a generator, a turbine-side converter, a grid-side converter, and a box transformer.

[0010] As a preferred embodiment, a communication delay module is added to the simulation module of the wind turbine test system to simulate the delay of current simulation sampling and digital-to-analog conversion.

[0011] In a preferred embodiment, the power grid simulation device in the wind turbine test system simulation module includes a DC voltage source, an inverter, and an output transformer.

[0012] As a preferred embodiment, the real power grid simulation module of the area connected to the wind turbine after it is actually put into operation includes other wind turbine models of the wind farm, the collection and transmission part model, and the large power grid model of the connected area; the collection and transmission part model includes transmission lines, transformers, and converter valves in scenarios such as DC collection and transmission, power frequency AC transmission, or low frequency AC transmission.

[0013] In a preferred embodiment, the wind turbine controller is divided into a turbine-side controller and a grid-side controller, both of which adopt an inner and outer loop dual closed-loop control algorithm.

[0014] In a preferred embodiment, the current signal communication module includes a communication module 1 installed on the side of the wind turbine test system simulation module and a communication module 2 installed on the side of the real power grid simulation module; the communication module 1 is used to encapsulate the three-phase current data of the test grid connection point in the wind turbine test system simulation module into data frames; the communication module 2 is used to decode the data frames.

[0015] In a preferred embodiment, the voltage signal feedback module includes a communication module 3 installed on the side of the real power grid simulation module and a communication module 4 installed on the side of the power supply grid simulation device controller; the communication module 3 is used to encapsulate the three-phase current data of the real grid connection point in the real power grid simulation module into data frames; the communication module 4 is used to decode the data frames.

[0016] In a preferred embodiment, both the current signal communication module and the voltage signal feedback module are composed of communication software algorithms, computing hardware, and physical layer transceivers.

[0017] In a preferred embodiment, both the current signal communication module and the voltage signal feedback module have communication protocol conversion functions.

[0018] The present invention has the following beneficial effects: 1. This invention replaces the real power grid with a power grid simulation device and a high-precision real-time simulation model, enabling all tests to be completed in an onshore laboratory environment. This completely avoids the potential risks associated with directly connecting wind turbines to the real power grid for testing. Simultaneously, it eliminates the high costs and complexity of offshore operations, significantly reducing the economic and time costs of testing.

[0019] 2. This invention, by constructing a detailed real-time simulation model that includes the wind farm collection system and the regional power grid, can accurately reproduce the impedance characteristics, dynamic response, and metastable state characteristics of the real power grid at the actual grid connection point of the wind turbine. This makes the output of the power grid simulation device no longer a simple ideal power source, but a highly realistic representation of the actual operating conditions faced by the wind turbine in the actual power grid environment, thereby greatly improving the accuracy and reliability of the test results.

[0020] 3. This invention constructs a complete closed-loop test system by cooperating with two hardware-in-the-loop simulation modules and the physical power grid simulation device controller, and supplemented by a high-speed communication module.

[0021] 4. The system architecture of this invention is flexible, and the communication module has a protocol conversion function, which can be compatible with simulation equipment and controllers from different manufacturers and models, reducing the difficulty of system integration.

[0022] 5. By adding a communication delay element to the simulation, this invention can simulate the delay effects of sampling, conversion and transmission in a real hardware platform, making the hardware-in-the-loop test environment closer to the actual digital physical system, and further ensuring the effectiveness of the control strategy verification and the reliability of its application in actual devices. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the system structure of the present invention; Figure 2 This is a schematic diagram of the system structure in Example 2; Figure 3 Schematic diagram of a wind farm collection and transmission system; Figure 4 This is a schematic diagram of the circuit structure of a power grid simulation device; Figure 5 This is a schematic diagram of the circuit topology of inverter unit 1 in the power grid simulation device. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be understood that the step numbers used in the text are for ease of description only and are not intended to limit the order in which the steps are performed.

[0026] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0027] The terms “comprising” and “including” indicate the presence of the described feature, whole, step, operation, element and / or component, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0028] The term “and / or” refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes these combinations.

[0029] Example 1: See Figure 1 A hardware-in-the-loop test system for wind turbine grid-connected performance based on real-time simulation of the power grid environment, including: The simulation module of the wind turbine test system, which connects the offshore wind turbine to the power grid simulation device, is used to simulate the operating status of the hardware of the wind turbine grid-connected performance test system, which is composed of the offshore wind turbine and the power grid simulation device. The real power grid simulation module for the power access area is used to simulate the electrical characteristics of the real power grid in the area after the wind turbine under test is actually put into operation; The wind turbine controller is used to send drive signals to the wind power converter and sample the voltage and current information of the DC, input and output terminals of the converter for closed-loop control and signal modulation. The power grid simulation device controller is used to send drive signals to the power grid simulation device and sample the voltage and current information of the DC, input and output terminals of the power grid simulation device converter. The current signal communication module encapsulates the three-phase current data of the test grid connection point in the wind turbine test system simulation module into communication frames and transmits them to the real power grid simulation module for decoding and application. The voltage signal feedback module encapsulates the three-phase voltage data of the actual grid connection point in the real power grid simulation module into communication frames, and transmits them to the controller of the power grid simulation device. After decoding, the data serves as the control reference value for the output voltage of the power grid simulation device.

[0030] As a preferred embodiment of this example, the wind turbine generator set in the wind turbine test system simulation module includes a wind turbine mechanical power calculation unit, a generator, a turbine-side converter, a grid-side converter, and a box transformer.

[0031] In this embodiment, the mechanical power calculation of the wind turbine can be simplified based on the MPPT curve directly according to the wind speed (ignoring the response time of the mechanical parts), or it can be calculated based on the wind speed using methods such as a reduced-order mechanical model. The generator can be a permanent magnet synchronous direct-drive, doubly-fed, or electrically excited synchronous generator. The converter consists of controllable power semiconductor devices and an output filter, including two-level, three-level, and modular multi-level topologies. The box transformer is used to boost the voltage at the output of the wind turbine converter to the voltage of the wind farm's collector lines.

[0032] As a preferred embodiment of this example, a communication delay module is added to the wind turbine test system simulation module to simulate the delay of current simulation sampling and digital-to-analog conversion.

[0033] In this embodiment, a communication delay is added to simulate the delay in current simulation sampling and digital-to-analog conversion in a real hardware test platform.

[0034] As a preferred embodiment of this invention, the power grid simulation device in the wind turbine test system simulation module includes a DC voltage source, an inverter, and an output transformer.

[0035] In this embodiment, a DC voltage source is used to construct the DC voltage. This can be a DC voltage source itself, or a rectifier can be used to rectify the AC voltage from the AC grid into a DC voltage. The inverter converts this DC bus voltage into an output voltage and controls the output voltage waveform according to controller instructions. An output transformer is used to transform the output voltage of the grid simulation device to match the voltage of the wind farm's collector lines. The inverter of the grid simulation device can employ a two-level or multi-level topology, or a cascaded or modular multi-level topology.

[0036] As a preferred embodiment of this example, the real power grid simulation module of the area connected to the wind turbine after it is actually put into operation includes other wind turbine models of the wind farm, the collection and transmission part model, and the large power grid model of the connected area; the collection and transmission part model includes transmission lines, transformers, and converter valves in scenarios such as DC collection and transmission, power frequency AC transmission, or low frequency AC transmission.

[0037] In this embodiment, the model for the collection and transmission section includes, but is not limited to, transmission lines, transformers, and flexible DC converter valves in scenarios such as DC collection and flexible DC transmission, AC transmission, or low-frequency transmission. The large power grid model of the access area can, depending on the situation, be a complete power grid model of the area where the wind farm is connected, or, to reduce the model size, only a portion of the power grid structure can be retained, with some power sources or loads represented by PQ, PV, Vθ nodes or equivalents. Alternatively, a multi-order RLC impedance plus an ideal voltage source can be used to represent an equivalent power grid or a part of the power grid.

[0038] In a preferred embodiment of this invention, the wind turbine controller is divided into a turbine-side controller and a grid-side controller, both of which employ an inner and outer loop dual closed-loop control algorithm.

[0039] In this embodiment, the turbine-side control generally employs a power outer loop and a current inner loop control algorithm to control the wind turbine's speed to track a reference value. The grid-side control also uses a dual closed-loop control algorithm with inner and outer loops to control the wind turbine's grid-side output power or voltage frequency and phase angle.

[0040] In a preferred embodiment of this invention, the current signal communication module includes a communication module 1 installed on the side of the wind turbine test system simulation module and a communication module 2 installed on the side of the real power grid simulation module; the communication module 1 is used to encapsulate the three-phase current data of the test grid connection point in the wind turbine test system simulation module into data frames; the communication module 2 is used to decode the data frames.

[0041] In a preferred embodiment of this invention, the voltage signal feedback module includes a communication module 3 installed on the side of the real power grid simulation module and a communication module 4 installed on the side of the power grid simulation device controller; the communication module 3 is used to encapsulate the three-phase current data of the real grid connection point in the real power grid simulation module into data frames; the communication module 4 is used to decode the data frames.

[0042] In this embodiment, after decoding the data frame, the communication module 4 transmits the actual grid connection point voltage to the grid simulation device controller. The grid simulation device controller uses this voltage as a voltage reference value to control the grid simulation device to output the test grid connection point voltage.

[0043] In a preferred embodiment of this invention, both the current signal communication module and the voltage signal feedback module are composed of communication software algorithms, computing hardware, and physical layer transceivers.

[0044] In this embodiment, the software algorithm can be integrated into an FPGA, ARM, DSP, industrial control computer, or PC. Communication modules 1-4 can be chips or software algorithms integrated into the simulation module / power grid simulation device controller, or they can be separate peripheral hardware communication devices, or they can be composed of an integrated communication module integrated into the simulation module / power grid simulation device controller and an external communication device.

[0045] In a preferred embodiment of this invention, both the current signal communication module and the voltage signal feedback module have communication protocol conversion functions.

[0046] In this embodiment, the communication protocol conversion function enables the wind turbine test system simulation module, the real power grid simulation module, and the power grid simulation device controller to communicate with each other even if they support different communication protocols.

[0047] Example 2: Both the wind turbine testing system simulation module and the real power grid simulation module use the RTDS simulator. The system framework is as follows: Figure 2 As shown.

[0048] the following Figure 3 The AC collection and transmission model in the diagram is a specific implementation example. W1 is the wind turbine under test, and S in the diagram represents the actual power grid of the access area. This scenario uses a model of five aggregated wind turbine units, forming two wind turbine units P1 and P2. W1 is a single wind turbine unit model, W2, W3, and W4 are equivalent units from the same wind farm, and W5 and W6 are equivalent units from neighboring wind farms. Each wind turbine has a capacity of 10MW. They are collected via a 35 kV collection line, then stepped up to 220 kV via an offshore substation and transmitted via a submarine AC cable line, finally stepped up to 500 kV and connected to the onshore AC power grid.

[0049] For S in the diagram, which represents the actual power grid module of the access area, a city power grid module is used. The loads of other wind farms and substations connected to this regional power grid are all equivalent using PQ nodes. At the interface between the regional power grid and the main power grid, the main power grid is equivalent to an inductor + ideal voltage source model based on the short-circuit ratio. The actual power grid module of the access area is solved and run in real time within the actual power grid simulation module.

[0050] The offshore wind turbines used in the study all adopt a permanent magnet synchronous direct drive structure. The permanent magnet synchronous direct drive wind turbine mainly includes the wind turbine and its pitch and yaw system, drive shaft, low-speed synchronous generator, full-power converter and other components, as well as the converter DC bus unloading protection circuit.

[0051] The generator-side converter of the permanent magnet synchronous wind turbine adopts a control strategy of an outer power loop and an inner current loop to keep the wind turbine operating at its maximum power point. The grid-side converter also employs a dual-loop control system, with the outer loop using constant DC voltage and constant reactive power control. The inner loop control of the grid-side converter uses a dq decoupled current control method.

[0052] The power grid simulation module includes a DC voltage source, an inverter, and an output transformer. The DC voltage source is a 5000V DC voltage source. Figure 4 As shown, the inverter consists of five cascaded inverter units with identical circuit structures. Figure 5 As shown, taking inverter unit 1 as an example, it consists of two three-phase NPC inverters, with the same phase of the two three-phase NPC inverters connected to the input terminal of the same output transformer. The output transformers of the five inverter units are cascaded on the output side and, after being filtered by an LC filter, are connected to the 35kV side of the offshore wind turbine under test after voltage boosting.

[0053] The power grid simulation device employs dual closed-loop PI control for both voltage and current. The inner loop controls the output point current, while the outer loop controls the filter to track the grid-side voltage reference value. The controller of the power grid simulation device uses the actual three-phase voltage data of the grid connection point in the real regional power grid in the real power grid simulation module as the voltage reference value. After passing through the control loop and modulation stage, it generates a drive pulse signal, which is transmitted to the power grid simulation device in the wind turbine test system simulation module.

[0054] Communication module 1 transmits the three-phase current data of the test grid connection point to communication module 2 via the Aurora protocol. After decoding the data frame, communication module 2 transmits the actual three-phase current data of the grid connection point to the data register of the actual power grid simulation module, which serves as the reference value for the controlled current source connected in parallel at the interface of the wind turbine unit to the actual power grid in the area.

[0055] Communication module 3 uses the Aurora communication protocol to transmit the actual three-phase voltage data of the grid connection point in the real power grid simulation module to communication module 4. Communication module 4 consists of a communication protocol conversion module and an integrated communication module of the power grid simulation device controller. First, the communication protocol conversion module converts the Aurora communication protocol into a communication protocol compatible with the power grid simulation device controller. Then, the integrated communication module decodes the communication frames and stores the voltage data in the controller's registers.

[0056] The power grid simulation device controller uses the voltage at the interface where the wind turbine unit in the real power grid is connected to the real power grid in the real power grid simulation module as the voltage reference value, and controls the power grid simulation device to output this voltage, thereby simulating the characteristics of the real power grid.

[0057] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A wind turbine grid code compliance hardware-in-the-loop test system for real-time simulation of a grid environment, characterized in that The application relates to a wind turbine test system simulation module connected with a power supply grid simulation device, which is used for simulating the operation state of a wind turbine grid performance test system hardware composed of the wind turbine and the power supply grid simulation device. The application relates to a real grid simulation module of a power access area, which is used for simulating the electrical characteristics of a real grid of an area accessed by the wind turbine after the wind turbine is actually put into operation. The application relates to a wind turbine controller, which is used for sending driving signals to a wind power converter and sampling the voltage and current information of a direct current, an input and an output end of the converter for closed-loop control and signal modulation. The application relates to a power supply grid simulation device controller, which is used for sending driving signals to the power supply grid simulation device and sampling the voltage and current information of a direct current, an input and an output end of a converter of the power supply grid simulation device. The application relates to a current signal communication module, which is used for packaging the three-phase current data of a test grid point in the wind turbine test system simulation module into a communication frame and then transmitting the communication frame to the real grid simulation module for decoding and application. The application relates to a voltage signal feedback module, which is used for packaging the three-phase voltage data of a real grid point in the real grid simulation module into a communication frame and then transmitting the communication frame into the power supply grid simulation device controller, which is decoded and used as a control reference value of the output voltage of the power supply grid simulation device. The wind turbine in the wind turbine test system simulation module comprises a wind turbine mechanical power calculation unit, a generator, a machine-side converter, a grid-side converter and a box transformer.

2. The wind turbine grid code compliance HIL test system for real-time simulation of grid code compliance of wind turbines in a grid environment according to claim 1, characterized in that, A communication delay module is added in the wind turbine test system simulation module, which is used for simulating the delay of current simulation sampling and digital-analog conversion. 3.The wind turbine grid code compliance HIL test system for real-time simulation of a joint grid environment according to claim 1, characterized in that, The power supply grid simulation device in the wind turbine test system simulation module comprises a direct current voltage source, an inverter and an output transformer.

4. The wind turbine grid code compliance HIL test system for real-time simulation of grid interaction according to claim 1, wherein, The real grid simulation module of the area accessed by the wind turbine after the wind turbine is actually put into operation comprises other wind turbine models of a wind power station, a collection and sending part model and a large grid model of the accessed area; the collection and sending part model comprises power transmission lines, transformers and converter valves in direct current collection and sending, power frequency alternating current sending or low frequency alternating current sending and the like.

5. The wind turbine grid code compliance HIL test system for real-time simulation of grid code compliance of wind turbines in a grid environment according to claim 1, characterized in that, The wind turbine controller is divided into a machine side and a grid side, and both adopt a double closed-loop control algorithm.

6. The wind turbine grid code compliance HIL test system for real-time simulation of grid code compliance of wind turbines in a grid environment according to claim 1, characterized in that, The current signal communication module comprises a communication module 1 installed on the wind turbine test system simulation module side and a communication module 2 installed on the real grid simulation module side; the communication module 1 is used for packaging the three-phase current data of a test grid point in the wind turbine test system simulation module into a data frame; and the communication module 2 is used for decoding the data frame.

7. The wind turbine grid code compliance HIL test system for real-time simulation of grid code compliance of wind turbines in a grid environment according to claim 1, characterized in that, The voltage signal feedback module comprises a communication module 3 installed on the real grid simulation module side and a communication module 4 installed on the power supply grid simulation device controller side; the communication module 3 is used for packaging the three-phase current data of a real grid point in the real grid simulation module into a data frame; and the communication module 4 is used for decoding the data frame. 8.The wind turbine grid code compliance HIL test system for real-time simulation of a joint grid environment according to claim 1, wherein, The current signal communication module and the voltage signal feedback module are both composed of a communication software algorithm, calculation hardware and a physical layer transceiving device. 9.The wind turbine grid code compliance HIL test system for real-time simulation of a joint grid environment according to claim 1, characterized in that, The current signal communication module and the voltage signal feedback module both have communication protocol conversion functions.

10. The wind turbine grid code compliance HIL test system for real-time simulation of a grid code environment according to claim 1, wherein, ​

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