Test system for access of network construction type converter to complex power system and control method of test system

Abstract

The invention discloses a test system for accessing a network construction type converter to a complex power system and a control method of the test system, and belongs to the technical field of converter test. The system comprises a real-time simulation module, a semi-physical networking type converter controller, a physical networking type converter and a controllable converter. According to the application, the preset complex power system model is constructed through the real-time simulation module, and the test system can simulate the power grid environment of the real complex power system in combination with the controllable converter, so that the performance of the tested network construction type converter in the complex power system can be tested. Moreover, based on the combination of a semi-physical networking type converter controller and a primary system model, a semi-physical networking type converter is formed, and the semi-physical networking type converter and a physical networking type converter jointly form a tested networking type converter, thereby achieving the large-scale hybrid simulation of semi-physical and physical, improving the construction convenience of a testing system, and improving the testing efficiency. And a basis is provided for carrying out network construction characteristic complete test and system-level characteristic test research on the network construction type converter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of converter testing, and in particular to a test system for grid-forming converter access to a complex power system and a control method thereof. BACKGROUND

[0002] As a controlled voltage source, the grid-forming converter can autonomously build internal potential and exhibit excellent self-synchronization performance without a phase-locked loop. This makes it play an important role in frequency regulation, voltage regulation, and oscillation suppression of the power grid. In order to ensure that the grid-forming converter can effectively support the power grid, it must undergo detailed testing before being connected to the actual power grid.

[0003] However, actual large power grid systems contain a large number of new energy generators, various loads, synchronous generators, grid-forming converters, transformers, and transmission lines, and the system capacity can reach the GW level. Since the grid-forming converter needs to adapt to such a large-capacity complex power system, its testing needs to be carried out in a test system that simulates a large-capacity complex power system. However, the construction of such a test system that simulates a large-capacity complex power system is relatively cumbersome. SUMMARY

[0004] The embodiments of the present application provide a test system for grid-forming converter access to a complex power system and a control method thereof, which improves the convenience of constructing a test system that simulates a large-capacity complex power system.

[0005] In a first aspect, the embodiments of the present application provide a test system for grid-forming converter access to a complex power system, which is applied to the testing process of a grid-forming converter to be tested in a complex power system. The test system comprises:

[0006] a real-time simulation module, configured to build a preset complex power system model and a semi-physical grid-forming converter primary system model connected to each other, and configured to output a modulation signal based on the preset complex power system model, a semi-physical alternating current signal, and a physical alternating current signal;

[0007] a semi-physical grid-forming converter controller, connected to the semi-physical grid-forming converter primary system model to form a semi-physical grid-forming converter, the semi-physical grid-forming converter controller being configured to control the semi-physical grid-forming converter primary system model to output the semi-physical alternating current signal to the preset complex power system model;

[0008] a physical grid-forming converter, connected to the preset complex power system model, the physical grid-forming converter being configured to output a physical alternating current signal of an alternating current port to the preset complex power system model;

[0009] The controllable converter is connected with the preset complex power system model and the real network type converter respectively, and is used for modulating based on a modulation signal to output a first electric signal to an alternating current port of the real network type converter.

[0010] The semi-real network type converter and the real network type converter jointly constitute the measured network type converter.

[0011] In some embodiments, the real-time simulation module is further configured to construct a real network type converter interface model, the real network type converter interface model being connected with the preset complex power system model, the alternating current port of the real network type converter and the controllable converter respectively.

[0012] The real network type converter interface model is configured to output the real alternating current signal processed by the first aggregation mode to the preset complex power system model, and output the modulation signal to the controllable converter.

[0013] In some embodiments, the real alternating current signal comprises a real alternating current current signal.

[0014] The real network type converter interface model comprises:

[0015] An aggregation unit is connected with the preset complex power system model and the alternating current port of the real network type converter respectively, and is configured to output the real alternating current current signal processed by the first aggregation mode to the preset complex power system model.

[0016] In some embodiments, the semi-real network type converter primary system model is further configured to output the semi-real alternating current signal processed by the second aggregation mode to the preset complex power system model.

[0017] In some embodiments, the test system further comprises:

[0018] A coordination controller is connected with the semi-real network type converter controller and the real network type converter respectively, and is configured to determine power instructions corresponding to the semi-real network type converter and the real network type converter respectively based on the operating state of the semi-real network type converter, the operating state of the real network type converter and the preset power instruction, and send the power instructions to the corresponding semi-real network type converter controller and real network type converter.

[0019] In some embodiments, the coordination controller comprises a main coordination controller and a plurality of sub-coordination controllers, the main coordination controller being connected with each sub-coordination controller, and any one sub-coordination controller being connected with the semi-real network type converter controller and / or the real network type converter.

[0020] In some embodiments, the real-time simulation module is configured to output the modulation signal based on the preset complex power system model, the semi-physical AC electrical signal, and the physical AC electrical signal, including:

[0021] constructing the preset complex power system model, the preset complex power system model including complex power models in each preset operating state;

[0022] outputting a modulation signal corresponding to the complex power model in each preset operating state based on the complex power model in each preset operating state, the semi-physical AC electrical signal, and the physical AC electrical signal.

[0023] In some embodiments, the test system further includes:

[0024] a DC power supply connected to the DC side of the physical grid-forming converter, the DC power supply configured to provide a second electrical signal to the DC side of the physical grid-forming converter.

[0025] In some embodiments, the real-time simulation module includes:

[0026] a real-time simulation interface board card, the semi-physical grid-forming converter controller connected to the semi-physical grid-forming primary system model through the real-time simulation interface board card, and the physical grid-forming converter connected to the preset complex power system model through the real-time simulation interface board card.

[0027] In a second aspect, the application also provides a control method of a test system of a grid-forming converter accessing a complex power system, the control method including:

[0028] starting the real-time simulation module, the real-time simulation module configured to construct the preset complex power system model and the semi-physical grid-forming primary system model connected to each other, and output a modulation signal based on the preset complex power system model, the semi-physical AC electrical signal, and the physical AC electrical signal;

[0029] starting the semi-physical grid-forming converter controller, the semi-physical grid-forming converter controller configured to control the semi-physical grid-forming primary system model to output the semi-physical AC electrical signal to the preset complex power system model;

[0030] starting the controllable converter, the controllable converter configured to modulate based on the modulation signal to output a first electrical signal to the AC port of the physical grid-forming converter;

[0031] starting the physical grid-forming converter, the physical grid-forming converter configured to output a physical AC electrical signal of the AC port to the preset complex power system model;

[0032] The preset complex power system model comprises complex power models in each preset operating state; and the real-time simulation module outputs a modulation signal corresponding to the complex power model in each preset operating state based on the complex power model in each preset operating state, the semi-physical alternating current signal, and the physical alternating current signal.

[0033] The test system for the grid-connected converter accessing the complex power system provided in the embodiments of the present application comprises a real-time simulation module, a semi-physical grid-connected converter controller, a physical grid-connected converter, and a controllable converter. The real-time simulation module is used to build a preset complex power system model and a semi-physical grid-connected converter primary system model. The test system can simulate the grid environment of a real complex power system by using the preset complex power system model, thereby facilitating the test of the performance of the measured grid-connected converter in the complex power system. Moreover, the semi-physical grid-connected converter is formed by combining the semi-physical grid-connected converter controller with the primary system model, and the semi-physical grid-connected converter and the physical grid-connected converter jointly constitute the measured grid-connected converter, thereby realizing large-scale hybrid simulation of the semi-physical and physical grid-connected converters and improving the convenience of building the test system for simulating a large-capacity complex power system, which provides a basis for the research on the grid characteristics test and system-level characteristics test of the grid-connected converter.

[0034] The control method for the test system for the grid-connected converter accessing the complex power system provided in the embodiments of the present application is applied to the test system for the grid-connected converter accessing the complex power system, and the control method for the test system for the grid-connected converter accessing the complex power system comprises the effects of all the features of the test system for the grid-connected converter accessing the complex power system, which will not be described herein. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0036] Figure 1 A structural block diagram of the test system for the grid-connected converter accessing the complex power system provided in the embodiments of the present application is shown in FIG. 1;

[0037] Figure 2 Another structural block diagram of the test system for the grid-connected converter accessing the complex power system provided in the embodiments of the present application is shown in FIG. 2;

[0038] Figure 3 A simulation schematic diagram of the semi-physical grid-connected converter provided in the embodiments of the present application is shown in FIG. 3;

[0039] Figure 4 A structure diagram of a physical network construction type converter interface model provided by an embodiment of the present application is shown in the following figure;

[0040] Figure 5 A simplified structure diagram of a complex power system to which multiple semi-physical and physical network construction type converters are connected provided by an embodiment of the present application is shown in the following figure;

[0041] Figure 6 A control method of a test system of a complex power system to which a network construction type converter is connected provided by an embodiment of the present application is shown in the following figure;

[0042] Figure 7 A complex power system topology structure diagram when semi-physical and physical network construction type converters are all energy storage converters provided by an embodiment of the present application is shown in the following figure. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0044] In the embodiments of the present application, at least one refers to one or more; multiple refers to two or more than two. In the description of the present application, the terms “first”, “second”, “third” and the like are only used to distinguish the description purposes, and cannot be understood as indicating or implying relative importance, nor can be understood as indicating or implying order.

[0045] In the present specification, the reference “one embodiment” or “some embodiments” and the like means that the specific features, structures or characteristics described in connection with the embodiment are included in one or more embodiments of the present application. Therefore, in the present specification, the terms “include”, “contain”, “have” and their variants mean “include but not limited to”, unless otherwise specifically emphasized.

[0046] It should be noted that in the embodiments of the present application, the association relationship of the associated objects described by “and / or” means that there can be three relationships, for example, A and / or B can mean that there are three cases of A alone, A and B together, and B alone. In addition, the character “ / ,” unless otherwise specified, generally represents a “or” relationship between the associated objects before and after it.

[0047] It should be noted that the "connection" in the embodiments of the present application can be understood as an electrical connection, and the connection between two electrical elements can be direct or indirect connection between the two electrical elements. For example, A and B are connected, which can be direct connection between A and B, or indirect connection between A and B through one or more other electrical elements. In addition, "connection" can also be understood as signal connection, that is, signal transmission between the two, without physical connection.

[0048] In recent years, with the continuous increase of new energy installed capacity in China, the penetration rate of new energy in the power system is continuously increasing, and the inertia and grid strength of the power system are continuously decreasing, which brings great challenges to the stable operation of the power system. As a controlled voltage source, grid-forming converter has the ability to build internal potential, and can have good self-synchronization performance without phase-locked loop, and plays an important role in system frequency regulation, voltage regulation, system oscillation suppression and other stability control.

[0049] As a controlled voltage source, grid-forming converter can autonomously build internal potential and exhibit excellent self-synchronization performance without phase-locked loop. This makes it play an important role in grid frequency regulation, voltage regulation, and oscillation suppression and other stability control. In order to ensure that the grid-forming converter can effectively support the grid, it must be tested in detail before being connected to the actual grid.

[0050] In order to ensure that the grid-forming converter can effectively support the actual grid, the grid-forming converter needs to be tested in detail before being connected to the actual grid. Grid-forming converter testing can be carried out based on a test vehicle or a third-party certification test platform. However, since the test vehicle or the third-party certification test platform cannot truly simulate the operating characteristics and fault characteristics of the actual large power grid, it cannot test the mutual influence between the grid-forming converter and the grid, and therefore cannot effectively test the real response of the grid-forming converter in the actual grid and its support for the actual grid.

[0051] In the actual large power grid, the system contains a large number of new energy generators, various types of loads, synchronous generators, grid-forming converters, transformers, transmission lines, collection lines, etc., and the system capacity can be as high as GW or more. In order to effectively support the complex power grid system, the grid-forming converter needs to be tested by a large-scale test system, which increases the complexity of the test system, and thus makes it more cumbersome to build a test system that simulates a large-capacity complex power system. Therefore, during the testing of the grid-forming converter, how to simulate the response characteristics of the actual power grid to provide a more realistic test environment for the grid-forming converter, and how to connect the grid-forming converter to the large power grid on a large scale to verify the real support of the grid-forming converter for the actual power grid, are two difficult problems in current research.

[0052] Therefore, the application provides a control method of a test system of a grid-forming converter accessing a complex power system, aiming to solve at least one of the above technical problems.

[0053] Please refer to Figure 1 as shown, Figure 1 A structural block diagram of a test system of a grid-forming converter accessing a complex power system is provided for the embodiments of the application.

[0054] The embodiments of the application provide a test system of a grid-forming converter accessing a complex power system, which is applied to a test process of a measured grid-forming converter in a complex power system, and the test system comprises:

[0055] A real-time simulation module is configured to construct a preset complex power system model and a semi-physical grid-forming converter primary system model connected with each other, and to output a modulation signal based on the preset complex power system model, a semi-physical alternating current signal and a physical alternating current signal;

[0056] A semi-physical grid-forming converter controller is connected with the semi-physical grid-forming converter primary system model to constitute a semi-physical grid-forming converter, and the semi-physical grid-forming converter controller is configured to control the semi-physical grid-forming converter primary system model to output the semi-physical alternating current signal to the preset complex power system model;

[0057] A physical grid-forming converter is connected with the preset complex power system model, and the physical grid-forming converter is configured to output a physical alternating current signal of an alternating current port to the preset complex power system model;

[0058] A controllable converter is connected with the preset complex power system model and the physical grid-forming converter respectively, and the controllable converter is configured to modulate based on the modulation signal to output a first electric signal to the alternating current port of the physical grid-forming converter;

[0059] The semi-physical grid-forming converter and the physical grid-forming converter jointly constitute the measured grid-forming converter.

[0060] Please refer to Figure 2 as shown, Figure 2 A structural block diagram of another test system of a grid-forming converter accessing a complex power system is provided for the embodiments of the application.

[0061] The real-time simulation module is connected with the semi-physical grid-connected type converter controller, the AC port of the physical grid-connected type converter, and the controllable converter. Then, the real-time simulation module outputs the modulation signal to the controllable converter based on the collected semi-physical AC signals, physical AC signals, and the constructed preset complex power system model. The modulation signal can simulate the dynamic behavior and response characteristics of the grid-connected point of the real power system, so that the controllable converter is modulated to simulate the grid conditions corresponding to the modulation signal. It should be noted that the physical AC signals include at least one of the voltage and current of the AC port of the physical grid-connected type converter, and the semi-physical AC signals include at least one of the voltage and current of the AC port of the semi-physical grid-connected type converter. The real-time simulation module can collect the voltage and current of the AC port of the physical grid-connected type converter through the voltage sensor and the current sensor.

[0062] In some embodiments, the real-time simulation module includes a real-time simulation interface board card, the semi-physical grid-connected type converter controller is connected with the semi-physical grid-connected type converter primary system model through the real-time simulation interface board card, and the physical grid-connected type converter is connected with the preset complex power system model through the real-time simulation interface board card. For example, the real-time simulation module can include a simulation server, a real-time simulator, and a real-time simulation interface board card. The simulation server is used to install and run real-time simulation software, construct a preset complex power system model containing a large-scale new energy power generation system and a large-scale grid-connected type converter through the real-time simulation software, and download the compiled model to the real-time simulator. At the same time, the semi-physical grid-connected type converter primary system model is also constructed based on the simulation server and the compiled model is downloaded to the real-time simulator. The real-time simulation interface board card is used to realize the real-time interface between the real-time simulator and the semi-physical grid-connected type converter controller module, the controllable converter, and the physical grid-connected type converter. The real-time simulator is used to calculate the preset complex power system model in real time to simulate the transient and steady state characteristics of the complex power system containing large capacity. In addition, the real-time simulator can receive the switching instructions and trigger pulses of the semi-physical grid-connected type converter controller module, the DC voltage of the controllable converter, and the voltage and current signals of the AC port of the physical grid-connected type converter in real time through the real-time simulation interface board card, and provide the voltage, current, and switching state signals of the semi-physical grid-connected type converter for the semi-physical grid-connected type converter controller module. In addition, the real-time simulator can calculate in real time based on the preset complex power system model, the semi-physical AC signals, and the physical AC signals, and then provide the modulation signal for the controllable converter in real time.

[0063] The preset complex power system model can include large-scale new energy power generation, different types of loads, large-capacity synchronous generator sets, grid-forming converters, transformers, transmission lines, collection lines, fault elements, and the like. The architecture, parameters, and grid-connection points of the grid-forming converters of the preset complex power system model are configured according to test requirements. The system capacity of the large-capacity complex power system can reach the GW level, and the simulation is specifically performed according to the actual power grid structure. The semi-physical grid-forming converter primary system model refers to the circuit components of the grid-forming converter constructed in the simulation environment, including DC-to-AC conversion, inverter configuration, and connection mode with the power grid, and the like. The semi-physical grid-forming converter primary system model can be used to simulate the physical behavior and electrical characteristics of the grid-forming converter. It should be noted that the controller is not included in the semi-physical grid-forming converter primary system model.

[0064] In the present application, the real-time simulation module can construct a large-capacity complex power system model containing a large-scale new energy power generation system through a mixed modeling method with different step sizes, simulate the transient and steady-state characteristics of a large power grid containing large-scale new energy grid connection, realize real-time interface of a large-capacity complex power system and a large-scale semi-physical and physical grid-forming converter, and provide a system grid connection interface for developing semi-physical and physical grid-forming converter access to large-capacity complex power system testing. Further, the semi-physical grid-forming converter and the physical grid-forming converter are both connected to the grid connection point provided by the preset complex power system model through the real-time simulation interface board card, so as to perform signal transmission. That is, the semi-physical AC electrical signal and the physical AC electrical signal are transmitted to the preset complex power system model through the grid connection point, and the modulated signal is output through the grid connection point.

[0065] Please refer to Figure 2 and Figure 3 as shown, Figure 3 a semi-physical grid-forming converter simulation schematic diagram provided by an embodiment of the present application.

[0066] The semi-physical grid-forming converter controller is connected to the semi-physical grid-forming converter primary system model in the real-time simulator through the real-time simulation interface board card, and the two form a semi-physical grid-forming converter. The overall structure of the semi-physical grid-forming converter is as shown in Figure 3As shown, the semi-physical network type converter controller realizes real-time control of the semi-physical network type converter. The semi-physical network type converter controller is used to control the semi-physical network type converter primary system model, so that the semi-physical network type converter primary system model outputs a semi-physical alternating current signal to the preset complex power system model. An example process in which the semi-physical network type converter controller controls the semi-physical network type converter primary system model is as follows: the semi-physical network type converter controller can send a switching instruction to the semi-physical network type converter primary system model through the real-time simulation interface board card to control the switching state of the semi-physical network type converter primary system model. In the on state of the semi-physical network type converter primary system model, the semi-physical network type converter controller can send a trigger pulse to the semi-physical network type converter primary system model through the real-time simulation interface board card to control the switching state of the power semiconductor device in the semi-physical network type converter primary system model through the trigger pulse, so as to realize conversion and regulation of electric energy, thereby enabling the semi-physical network type converter primary system model to generate a semi-physical alternating current signal to the preset complex power system model. It should be noted that the real-time simulation module also feeds back the voltage, current and switching state signals of the semi-physical network type converter primary system model to the semi-physical network type converter controller through the real-time simulation interface board card, so that the semi-physical network type converter controller can be adjusted in real time according to the current voltage, current and switching state.

[0067] The real-time simulation interface board card is connected to the preset complex power system model, and the real alternating current signal of the real network type converter is transmitted to the preset complex power system model through the real-time simulation interface board card. The process in which the real-time simulator collects the real alternating current signal can be as follows: the real network type converter first converts the port voltage and current signals into secondary signals through voltage sensors and current sensors respectively, and then connects the secondary signals to the real-time simulator through the real-time simulation interface board card, thereby realizing closed-loop connection of the real network type converter to the preset complex power system model. It should be noted that the real network type converter is a physical converter connected to the test system.

[0068] The controllable converter transmits a direct current voltage to the preset complex power system model through the real-time simulation interface board card, and the preset complex power system model transmits a modulation signal to the controllable converter through the real-time simulation interface board card, so that the controllable converter modulates based on the modulation signal to output a first electric signal to the alternating current port of the real network type converter. In this application, the controllable converter serves as a full-power physical interface of the real network type converter and the real-time simulation module, and provides an alternating current voltage for the real network type converter.

[0069] The controllable converter includes a rectifier converter and an inverter converter. Both the rectifier converter and the inverter converter can realize bidirectional power flow. The rectifier converter provides a direct-current voltage for the inverter converter. The inverter converter receives a modulation signal provided by the real-time simulator through a high-speed communication protocol, converts the modulation signal into an actual alternating-current voltage, and provides the alternating-current voltage to an alternating-current port of the physical network-constructed converter. That is, the inverter converter simulates fluctuations of voltage and frequency of a real power grid based on the modulation signal, and outputs the fluctuations to the alternating-current port of the physical network-constructed converter, so that the physical network-constructed converter actively follows a first electrical signal output by the controllable converter. The first electrical signal can be at least one of an alternating-current voltage and an alternating-current current on an alternating-current side of the controllable converter.

[0070] In this application, the semi-physical network-constructed converter and the physical network-constructed converter jointly constitute a measured network-constructed converter, that is, the total capacity of the semi-physical network-constructed converter and the physical network-constructed converter can meet the capacity required by the measured network-constructed converter of the preset complex power system. Further, the semi-physical network-constructed converter and the physical network-constructed converter can jointly support the capacity demand of the preset complex power system, so as to ensure that the network-constructed converter can effectively support the power grid, thereby enabling performance testing of the measured physical network-constructed converter applied in the complex power system.

[0071] Through the above technical solution, the application provides a test system for connecting a network-constructed converter to a complex power system. The test system includes a real-time simulation module, a semi-physical network-constructed converter controller, a physical network-constructed converter, and a controllable converter. The real-time simulation module is used to construct a preset complex power system model and a semi-physical network-constructed converter primary system model. The preset complex power system model enables the test system to simulate the power grid environment of a real complex power system, thereby facilitating performance testing of the measured network-constructed converter in the complex power system. Moreover, the semi-physical network-constructed converter controller is combined with the primary system model to form a semi-physical network-constructed converter. The semi-physical network-constructed converter and the physical network-constructed converter jointly constitute a measured network-constructed converter, realizing large-scale hybrid simulation of the semi-physical and physical network-constructed converters, improving the convenience of building the test system for simulating a large-capacity complex power system, and further providing a basis for conducting network-constructed characteristic complete testing and system-level characteristic testing research of the network-constructed converter.

[0072] In some embodiments, the real-time simulation module is configured to output a modulation signal based on the preset complex power system model, the semi-physical alternating-current electrical signal, and the physical alternating-current electrical signal, including:

[0073] The preset complex power system model includes complex power models in each preset operating state.

[0074] The complex power model under each preset operating state outputs a modulation signal corresponding to the complex power model under each preset operating state based on the complex power model under each preset operating state, the semi-physical alternating current signal, and the physical alternating current signal.

[0075] It should be understood that the real-time simulation module can be used to build and simulate the preset complex power system model. Through the preset complex power system model, the dynamic behavior and response characteristics of the grid connection point of the real complex power system can be simulated. The preset complex power system model includes complex power models under each preset operating state. The complex power models under each preset operating state can include switching new energy, adjusting new energy wind speed / illumination intensity, switching load, adjusting load size, switching synchronous generator, adjusting synchronous generator output, switching transformer, switching alternating current line, adjusting line parameter, switching fault, and switching network-type converter. The fault includes three-phase fault, two-phase fault, phase-to-phase fault, and single-phase fault. The fault mode includes metal fault and non-metal fault. The fault point can be set at any position of the complex power system. The complex power models under each preset operating state can be obtained by changing or adjusting the model structure and model parameters of the built complex power model. It should be noted that the preset complex power model can be one power model, and the complex power models under each preset operating state can be obtained by changing or adjusting the model structure or model parameters or adding disturbance of one power model.

[0076] In some embodiments, the real-time simulation module can build a corresponding preset complex power system model according to the actual power grid situation, then the real-time simulation module can collect semi-physical alternating current signals and physical alternating current signals in real time, and then the real-time simulation module can update and output modulation signals to the controllable converter in real time based on the collected semi-physical alternating current signals and physical alternating current signals and the built preset complex power system model. It can be understood that when the preset complex power system model changes, i.e., the complex power models under each preset operating state of the preset complex power system model change, the real-time simulation module will output new modulation signals for modulation, so that the controllable converter outputs the first electric signal to the alternating current port of the physical network-type converter. The alternating current port of the physical network-type converter will generate a new physical alternating current signal input to the real-time simulation module. The real-time simulation module will feed back the new physical alternating current signal to the power grid system to determine the physical alternating current signal of the physical network-type converter under fluctuation, realize simulation test of the physical network-type converter, and generate a new modulation signal based on the current preset complex power system model, semi-physical alternating current signal, and physical alternating current signal to the controllable converter. It should be noted that the semi-physical network-type converter in this application mainly relies on the semi-physical network-type converter controller for modulation to generate the semi-physical alternating current signal.

[0077] In some embodiments, the real-time simulation module can provide an initial reference voltage of a point of common coupling (PCC) of a real power system based on a preset complex power system model. Then, the real-time simulation module can determine a modulation signal based on the unlock total signal, the DC voltage of the controllable converter, and the initial reference voltage. Specifically, first, the real-time simulation module can determine a reference voltage of the PCC based on the unlock total signal and the initial reference voltage. For example, when the unlock total signal is a valid signal, the real-time simulation module can determine the real-time reference voltage of the PCC based on the product of the real-time data of the initial reference voltage and a preset start-stop coefficient. In this case, the preset start-stop coefficient can increase from a first threshold to a second threshold based on a first preset rate, so that the real-time value of the reference voltage of the PCC can increase based on the increase of the preset start-stop coefficient until it is equal to the initial reference voltage of the PCC. The first threshold can be greater than or equal to 0, the second threshold can be 1, and the first threshold can be less than the second threshold. The first preset rate can be a uniform rate, a uniform acceleration rate, or a variable rate, which can be set based on actual implementation requirements. In addition, when the unlock total signal is an invalid signal, the real-time simulation module can determine the real-time reference voltage of the PCC based on the product of the real-time data of the initial reference voltage and the preset start-stop coefficient. In this case, the preset start-stop coefficient can decrease from the second threshold to the first threshold based on a second preset rate, so that the real-time value of the reference voltage of the PCC can decrease based on the decrease of the preset start-stop coefficient. The second preset rate can be the same as the first preset rate in size but opposite in direction, or different from the first preset rate, which can be set based on actual implementation requirements. Then, the real-time simulation module can determine the modulation signal of the controllable power module based on the reference voltage and the DC voltage. For example, the modulation signal = half of the reference voltage of the PCC / the DC voltage.

[0078] It should be noted that the initial reference voltage can change when the preset complex power system model changes or the AC signal changes. In addition, the unlock total signal can be obtained by performing an AND operation on the unlock signals of the controllable converters connected to the same PCC. The DC voltage of the controllable converter can be obtained by performing an average calculation on the DC bus voltages of the controllable converters connected to the same PCC. It should also be noted that the controller corresponding to the controllable converter can output a trigger pulse to the inverter in the controllable converter based on the modulation signal, so that the controllable converter can be modulated. The unlock signal includes a valid signal and an invalid signal. The valid signal indicates that the controllable converter is working, and the invalid signal indicates that the controllable converter is not working. The unlock total signal is valid only when the unlock signals of the controllable converters connected to the same PCC are all valid. The unlock total signal is invalid when the unlock signal of any controllable converter connected to the same PCC is invalid.

[0079] Understandably, the real-time simulation module can simulate complex power models under various operating conditions and provide different voltage conditions in a timely manner to adapt to various power system scenarios. This allows it to cover a wide range of operating conditions for grid-connected converters, enabling modulation of controllable converters. This, in turn, helps to conduct complete grid-connected converter characteristic tests and system-level characteristic tests, thereby providing an in-depth evaluation of the grid-connected converter's grid performance.

[0080] Please see Figure 2 and Figure 4 As shown, Figure 4 A schematic diagram of the physical grid-type converter interface model provided in the embodiments of this application.

[0081] In some embodiments, the real-time simulation module is also used to construct a physical grid-type converter interface model, which is connected to a preset complex power system model, the AC port of the physical grid-type converter, and the controllable converter, respectively.

[0082] The physical grid-type converter interface model is used to process the physical AC signal using the first aggregation method and output it to the preset complex power system model; and the physical grid-type converter interface model is used to output the modulated signal to the controllable converter.

[0083] The physical grid-connected converter interface model is set between the preset complex power system model and the AC port of the physical grid-connected converter. The physical AC signal passes through the real-time simulation interface board, and then is processed by the physical grid-connected converter interface model before being output to the preset complex power system model. Furthermore, the modulated signal output from the preset complex power system model passes through the physical grid-connected converter interface model and then is transmitted to the controllable converter via the real-time simulation interface board.

[0084] Understandably, physical grid-connected converters are connected to the physical grid-connected converter interface model in the real-time simulator through a real-time simulation interface board. The physical grid-connected converter interface model is based on the first aggregation method, which can realize the large-scale access of physical grid-connected converters to large-capacity complex power systems, and improve the convenience of building a test system for simulating large-capacity complex power systems.

[0085] like Figure 4 As shown, in some embodiments, the physical AC signal includes the physical AC current signal;

[0086] The physical grid-type converter interface model includes:

[0087] The aggregation unit is connected to the AC port of the preset complex power system model and the physical grid-type converter, respectively. The aggregation unit is used to process the physical AC current signal using the first aggregation method and output it to the preset complex power system model.

[0088] It needs to be understood that the aggregation unit makes the real AC power signal pass through the real-time simulation interface board card, and then the real AC power signal is output to the preset complex power system model after being processed by the aggregation unit in the first aggregation mode. It needs to be explained that in this application, the first aggregation mode refers to multiplying the real AC current signal by a preset first multiple. Further, the real network-type converter capacity remains unchanged after power aggregation, that is, the voltage level in the real network-type converter interface model remains unchanged, and the current is multiplied by a preset first multiple to achieve a preset first multiple power aggregation. For example, the aggregation unit can use an analog multiplier, an operational amplifier, a multiplier circuit, etc. to multiply the real AC current signal by a preset first multiple.

[0089] It can be understood that the aggregation unit can realize the access of large-scale real network-type converters to large-capacity complex power systems, thereby reducing the complexity of the test system.

[0090] Please refer to Figure 4 As shown in the figure, the real network-type converter interface model further includes:

[0091] The current source is connected with the AC port of the real network-type converter and the aggregation unit respectively, and the current source is used to convert the real AC power signal collected from the AC port of the real network-type converter into a current signal, that is, the real AC power signal collected by the sensor from the AC port of the real network-type converter is sent to the current source, so that the current source converts the current and outputs the converted current to the aggregation unit for first aggregation method processing.

[0092] The filter unit is connected with the grid connection point of the preset complex power system model and the aggregation unit respectively, and the real AC current signal is sent to the grid connection point of the preset complex power system model after being processed by the aggregation unit in the first aggregation mode and then filtered by the filter unit. It can be understood that the filter unit can effectively suppress high-frequency noise and interference signals, and the filter unit can smooth the fluctuations and spikes in the signal to provide more stable real AC current signals. For example, the filter unit can include an inductor L1, an inductor L2, and a capacitor C, one end of the capacitor C is grounded, the other end of the capacitor C is connected with one end of the inductor L1 and one end of the inductor L2 respectively, the other end of the inductor L1 is connected with the grid connection point of the preset complex power system model, and the other end of the inductor L2 is connected with the output end of the aggregation unit.

[0093] It can be understood that the physical network construction type converter interface model can include a current source, an aggregation unit, a filter unit, etc., that is, the physical alternating current signal sequentially passes through the current source, the aggregation unit, and the filter unit and is then output to the preset complex power system model. While realizing large-scale physical network construction type converter access to a large-capacity complex power system to reduce the complexity of the test system, the interference in the signal can also be reduced to provide more stable physical alternating current signals, thereby ensuring the stability of the test system.

[0094] It also needs to be noted that the position of the physical network construction type converter interface model output modulation signal is located between the filter unit and the grid connection point, that is, the modulation signal output by the preset complex power system model is transmitted to the controllable converter through the real-time simulation interface board without being processed in the physical network construction type converter interface model. Please refer to Figure 4 Fig. 2 shows the U ref As the modulation signal of the controllable converter, the port voltage of the physical network construction type converter is of the same voltage level, and the port current i of the physical network construction type converter is multiplied by the aggregation multiple K and then fed back to the large-capacity complex power system.

[0095] In some embodiments, the semi-physical network construction type converter primary system model is also used to output the semi-physical alternating current signal processed by the second aggregation method to the preset complex power system model.

[0096] It needs to be understood that the semi-physical network construction type converter primary system model processes the semi-physical alternating current signal by the second aggregation method, that is, the voltage and current in the semi-physical alternating current signal of a single semi-physical network construction type converter are both increased by the square root of N times, thereby realizing N times power increase, and further realizing that one semi-physical network construction type converter is equivalent to the power of multiple semi-physical network construction type converters. The value of N can be set according to the actual implementation scheme requirements.

[0097] It needs to be understood that the semi-physical alternating current signal includes a semi-physical alternating voltage signal and a semi-physical alternating current signal. The semi-physical network construction type converter primary system model is used to output the semi-physical alternating current signal processed by the second aggregation method, that is, the semi-physical alternating voltage signal and the semi-physical alternating current signal are both multiplied to the preset complex power system model. It can be known that after the semi-physical alternating voltage signal and the semi-physical alternating current signal are both multiplied, the power aggregation of the preset second multiple is realized. For example, the second aggregation method is to increase the semi-physical alternating voltage signal and the semi-physical alternating current signal by times, thereby realizing N times power aggregation. It needs to be noted that the preset second multiple can be the same as or different from the preset first multiple.

[0098] For example, the semi-physical network type converter primary system model can be processed by the second aggregation method as follows: based on the semi-physical network type converter primary system model, the input impedance of the transformer valve side converter is unchanged, the system parameters of the converter primary system are not changed, the equivalent impedance of the converter before and after the aggregation is unchanged, the transformer ratio in the semi-physical network type converter primary system model is changed to increase the secondary voltage, the input impedance of the primary side is 1 / N before the aggregation, and the secondary voltage is increased by N times. Thus, the output power of the semi-physical network type converter primary system model is increased by N times, and the voltage and current of the direct current and alternating current in the semi-physical network type converter primary system model are increased by N times, and the series number and parallel number of the semi-physical network type converter primary system model are increased by N times.

[0099] It can be understood that the semi-physical network type converter primary system model is processed by the second aggregation method, which further reduces the scale of the physical network type converter connected to the test system, thereby further reducing the complexity of the test system. Furthermore, the semi-physical network type converter and the physical network type converter in the test system are connected to the large-capacity complex power model through power aggregation, thereby realizing the connection of the network type converter to the large-capacity complex power system, thereby meeting the test requirements of the complex power grid system while reducing the scale of the physical network type converter connected to the test system and improving the convenience of building the test system for simulating the large-capacity complex power system connected to the physical network type converter.

[0100] In some embodiments, the test system further comprises a coordination controller connected to the semi-physical network type converter controller and the physical network type converter, respectively, and the coordination controller is configured to determine the power instructions corresponding to the semi-physical network type converter and the physical network type converter based on the operating state of the semi-physical network type converter, the operating state of the physical network type converter, and the preset power instruction, and send the power instructions to the corresponding semi-physical network type converter controller and physical network type converter. It should be noted that the operating state of the semi-physical network type converter and the operating state of the physical network type converter refer to whether the converter is started, the size of the current and power of the converter, and other states. The preset power instruction can be the total power set according to the real-time demand of the power grid, and the total power of the sum of the power of all semi-physical network type converters processed by the second aggregation method and the power of the physical network type converter processed by the first aggregation method is equal to the total power of the preset power instruction.

[0101] As Figure 2It is shown that the coordination controller is used to realize the coordinated control of the semi-physical grid-connected converter and the physical grid-connected converter. The controllers of the semi-physical grid-connected converter and the physical grid-connected converter are directly connected to the coordination controller. The coordination controller calculates the real-time power instructions of the semi-physical grid-connected converter and the physical grid-connected converter according to the operating states and the preset power instructions of the semi-physical grid-connected converter and the physical grid-connected converter, and transmits them to the controllers of the corresponding semi-physical grid-connected converter and physical grid-connected converter, thereby controlling the output power of the semi-physical grid-connected converter and the physical grid-connected converter.

[0102] For example, the process of calculating the real-time power instructions of the semi-physical grid-connected converter and the physical grid-connected converter by the coordination controller according to the operating states and the preset power instructions of the semi-physical grid-connected converter and the physical grid-connected converter is as follows:

[0103] In the case that the operating states of the semi-physical grid-connected converter and the physical grid-connected converter are both starting, and the rated capacities and operating states of the semi-physical grid-connected converter and the physical grid-connected converter are both the same, the power aggregation equivalent multiple of the semi-physical grid-connected converter is m, i.e. the preset first multiple is m, the power aggregation equivalent multiple of the physical grid-connected converter is n, i.e. the preset second multiple is n, and the active power instruction in the preset power instruction is Pref. At this time, the active power real-time instruction of the semi-physical grid-connected converter and the physical grid-connected converter calculated by the coordination controller is Pref_PCS=Pref / (m+n). The distribution mode of the reactive power instruction is the same as that of the active power instruction, and the reactive power instruction in the preset power instruction is Qref, i.e. the reactive power real-time instruction of the semi-physical grid-connected converter and the physical grid-connected converter calculated by the coordination controller is Qref_PCS=Qref / (m+n). It should be noted that the preset power instruction includes the active power instruction and the reactive power instruction. Furthermore, the power instructions corresponding to the semi-physical grid-connected converter and the physical grid-connected converter respectively include the active power real-time instruction and the reactive power real-time instruction. It should also be noted that the rated capacities of the semi-physical grid-connected converter and the physical grid-connected converter refer to the rated capacities before the first aggregation mode and the second aggregation mode are processed.

[0104] In the case that the rated capacity of the semi-physical grid-connected converter and the physical grid-connected converter is different, the power instruction between different grid-connected converters is distributed according to the rated capacity proportion of the converter. For example, the power aggregation equivalent multiple of the semi-physical grid-connected converter is m, the rated capacity is Pn1, the power aggregation equivalent multiple of the physical grid-connected converter is n, and the rated capacity is Pn2. When the preset active power instruction is Pref, the real-time active power instruction of the semi-physical grid-connected converter calculated by the coordination controller is: Pref_PCS1=Pref*Pn1 / (m*Pn1+n*Pn2), and the real-time active power instruction of the physical grid-connected converter is: Pref_PCS2=Pref*Pn2 / (m*Pn1+n*Pn2). Further, when the preset reactive power instruction is Qref, the real-time reactive power instruction of the semi-physical grid-connected converter calculated by the coordination controller is: Qref_PCS1=Qref*Pn1 / (m*Pn1+n*Pn2), and the real-time active power instruction of the physical grid-connected converter is Qref_PCS2=Qref*Pn2 / (m*Pn1+n*Pn2).

[0105] It should be noted that when the power aggregation multiple of the semi-physical grid-connected converter and the physical grid-connected converter accessing the complex power system is 1, it is equivalent to that the semi-physical and physical grid-connected converters are not subjected to power aggregation treatment and directly access the complex power system. At this time, due to the small capacity of a single semi-physical and physical grid-connected converter, it is usually necessary to synchronously adjust the equivalent capacity and system parameters of the complex power system, so that the scale of the complex power system matches the grid-connected converter.

[0106] It can be understood that the test system can include one coordination controller, and when only one coordination controller is included, the controllers of all semi-physical grid-connected converters and physical grid-connected converters are directly connected to the coordination controller. Further, the coordination controller can calculate the real-time power instruction of each semi-physical grid-connected converter and physical grid-connected converter according to the operating state of the semi-physical grid-connected converter, the physical grid-connected converter and the system power instruction, and transmit it to the controller of the semi-physical grid-connected converter and the physical grid-connected converter, thereby realizing the coordinated control of the semi-physical grid-connected converter and the physical grid-connected converter.

[0107] However, in order to effectively support complex power grid systems, grid-forming converters need to be tested in large-scale test systems. Therefore, the test system can include at least one semi-physical grid-forming converter and at least one physical grid-forming converter, each of which is connected to a large-capacity complex power system through power aggregation, thereby realizing multi-node access of grid-forming converters to a large-capacity complex power system. It should be noted that each semi-physical grid-forming converter is composed of a semi-physical grid-forming converter controller and a semi-physical grid-forming converter primary system model. That is, multiple semi-physical grid-forming converters are composed of multiple semi-physical grid-forming converter controllers and corresponding multiple semi-physical grid-forming converter primary system models. It should also be noted that each semi-physical grid-forming converter and each physical grid-forming converter can be connected to different grid points, or at least one semi-physical grid-forming converter can be connected to the same grid point, or at least one physical grid-forming converter can be connected to the same grid point, or at least one semi-physical grid-forming converter and at least one physical grid-forming converter can be connected to the same grid point, which is determined according to actual scheme requirements. It should be noted that the amplification factor of each semi-physical grid-forming converter and each physical grid-forming converter after the corresponding aggregation mode processing can be different, that is, the power boosting factor corresponding to different semi-physical grid-forming converters can be different, and the power boosting factor corresponding to different physical grid-forming converters can also be different.

[0108] For example, in the case where the test system includes at least one semi-physical grid-forming converter and at least one physical grid-forming converter, the process of the coordination controller calculating the real-time power instruction of the semi-physical grid-forming converter and the physical grid-forming converter according to the operating state and the preset power instruction of the semi-physical grid-forming converter and the physical grid-forming converter is as follows:

[0109] Taking a test system containing two semi-physical network type converters and two physical network type converters as an example. In the case that the operating states of the semi-physical network type converters and the physical network type converters are all starting, and in the case that the rated capacities and the operating states of each semi-physical network type converter and each physical network type converter are all the same, the power aggregation equivalent multiples of the two semi-physical network type converters are m1 and m2 respectively, the power aggregation equivalent multiples of the two physical network type converters are n1 and n2 respectively, the active power instruction in the preset power instruction is Pref, and the real-time active power instruction of the semi-physical network type converter and the physical network type converter calculated by the coordination controller is Pref_PCS=Pref / (m1+m2+n1+n2). The reactive power instruction distribution mode is the same as that of the active power instruction, the reactive power instruction in the preset power instruction is Qref, and the real-time reactive power instruction of the semi-physical network type converter and the physical network type converter calculated by the coordination controller is Qref_PCS=Qref / (m1+m2+n1+n2). It can be further known that, in the case that the rated capacities and the operating states of the semi-physical network type converter and the physical network type converter are all the same, the real-time power instruction of each semi-physical network type converter and physical network type converter is obtained by dividing the preset power instruction by the sum of the equivalent multiples of all semi-physical network type converters and physical network type converters.

[0110] When the rated capacity of each semi-physical grid converter and each physical grid converter differs, the power command among different grid converters is allocated proportionally according to their rated capacity. For example, the power aggregation equivalent multiple of the first semi-physical grid converter is m1, and its rated capacity is Pn1; the power aggregation equivalent multiple of the second semi-physical grid converter is m2, and its rated capacity is Pn2; the power aggregation equivalent multiple of the first physical grid converter is n1, and its rated capacity is Pn3; and the power aggregation equivalent multiple of the second physical grid converter is n2, and its rated capacity is Pn4. When the active power command in the preset power command is Pref, the real-time active power command of the first semi-physical grid converter calculated by the coordinating controller is Pref_PCS1 = Pref*Pn1 / (m1*Pn1+m2*Pn2+n1*Pn3+n2*Pn4), and the real-time active power command of the second semi-physical grid converter is Pref_PCS2 = Pref*Pn2 / (m1*Pn1+m2*Pn4). The real-time active power command for the first physical grid-type converter is Pref_PCS3 = Pref*Pn3 / (m1*Pn1+m2*Pn2+n1*Pn3+n2*Pn4), and the real-time active power command for the second physical grid-type converter is Pref_PCS4 = Pref*Pn4 / (m1*Pn1+m2*Pn2+n1*Pn3+n2*Pn4). Furthermore, when the reactive power command in the preset power command is Qref, the real-time reactive power command of the first semi-physical grid converter calculated by the coordinating controller is Qref_PCS1 = Qref*Pn1 / (m1*Pn1+m2*Pn2+n1*Pn3+n2*Pn4), and the real-time reactive power command of the second semi-physical grid converter is Qref_PCS2 = Qref*Pn2 / (m1*Pn1+m2*Pn4). The real-time active power command for the first physical grid-connected converter is Qref_PCS3 = Qref*Pn3 / (m1*Pn1+m2*Pn2+n1*Pn3+n2*Pn4), and the real-time active power command for the fourth physical grid-connected converter is Qref_PCS4 = Qref*Pn4 / (m1*Pn1+m2*Pn2+n1*Pn3+n2*Pn4). Therefore, it can be understood that when the rated capacity of each semi-physical grid converter and each physical grid converter is different, the real-time power command for each semi-physical grid converter and physical grid converter is obtained by multiplying the preset power command by the rated capacity of the corresponding converter, and then dividing by the sum of the products of the equivalent multiples of all semi-physical grid converters and physical grid converters and their corresponding rated capacities. The preset power command includes both active power command and reactive power command.

[0111] It also needs to be understood that each grid-connected point in the test system corresponds to a modulation signal, that is, each grid-connected point corresponds to at least one controllable converter and one physical grid-forming converter interface model. Further, any grid-connected point in the test system outputs a modulation signal to the corresponding controllable converter through the physical grid-forming converter interface model and the real-time simulation interface board, and the controllable converter modulates based on the modulation signal to output a first electrical signal to the AC port of each physical grid-forming converter connected to the grid-connected point, and the grid-connected point collects the semi-physical AC electrical signal of the semi-physical grid-forming converter connected thereto and the physical AC electrical signal of the physical grid-forming converter to generate a new modulation signal.

[0112] Please refer to Figure 5 as shown, Figure 5 The simplified structure diagram of multiple semi-physical and physical grid-forming converters accessing a complex power system is provided for the embodiments of the present application.

[0113] It can be understood that by accessing multiple grid-forming converters, combined with the power aggregation method, it is possible to carry out GW-level grid-forming converter access simulation of a complex power system. For example, Figure 5 As shown, taking 1GW grid-forming energy storage access simulation as an example, assuming that the 1GW grid-forming energy storage is composed of 5 energy storage stations, each with a capacity of 200MW, then 3 semi-physical grid-forming energy storage converters with a single-machine rated power of 1.25MW and 2 full-power grid-forming energy storage converters with a single-machine rated power of 1.25MW can be used, which are respectively accessed to the complex power system through 160 times power aggregation.

[0114] In some embodiments, the coordination controller includes a main coordination controller and a plurality of sub-coordination controllers, the main coordination controller is connected with each sub-coordination controller, and any sub-coordination controller is connected with a semi-physical grid-forming converter controller and / or a physical grid-forming converter.

[0115] Figure 5 In the figure, the semi-physical and physical grid-forming converters are accessed to the preset complex power model through the power aggregation method. In order to meet the power coordination control of multiple semi-physical and physical grid-forming converters, the coordination controller is divided into two types of main coordination controller and sub-coordination controller, the controllers of the semi-physical grid-forming converter and the physical grid-forming converter are first accessed to the sub-coordination controller, and then accessed to the main coordination controller through the sub-coordination controller; wherein, one main coordination controller can be connected with multiple sub-coordination controllers, and any sub-coordination controller can be connected with at least one semi-physical grid-forming converter and / or physical grid-forming converter. It needs to be understood that the sub-coordination controller is essentially connected with the semi-physical grid-forming converter controller and the physical grid-forming converter controller.

[0116] That is, any one sub-coordination controller can be connected with at least one semi-physical networked converter, any one sub-coordination controller can be connected with at least one semi-physical networked converter and at least one physical networked converter, and any one sub-coordination controller can be connected with at least one semi-physical networked converter and at least one physical networked converter. Further, in some examples, the sub-coordination controllers can be divided into a first group of sub-coordination controllers and a second group of sub-coordination controllers, each sub-coordination controller in the first group of sub-coordination controllers being connected with at least one semi-physical networked converter, and each sub-coordination controller in the second group of sub-coordination controllers being connected with at least one physical networked converter. In other examples, the sub-coordination controllers can be a third group of sub-coordination controllers, and each sub-coordination controller in the third group of sub-coordination controllers can be connected with at least one semi-physical networked converter and at least one physical networked converter.

[0117] It should be understood that, in some embodiments, the sub-coordination controllers can also be divided into a first group of sub-coordination controllers and a third group of sub-coordination controllers, and the connection modes of the first group of sub-coordination controllers and the third group of sub-coordination controllers can be referred to the descriptions in the above embodiments, which will not be described here. In other embodiments, the sub-coordination controllers can also be divided into a second group of sub-coordination controllers and a third group of sub-coordination controllers, and the connection modes of the second group of sub-coordination controllers and the third group of sub-coordination controllers can be referred to the descriptions in the above embodiments, which will not be described here. In yet other embodiments, the sub-coordination controllers can also be divided into a first group of sub-coordination controllers, a second group of sub-coordination controllers, and a third group of sub-coordination controllers, and the connection modes of the first group of sub-coordination controllers, the second group of sub-coordination controllers, and the third group of sub-coordination controllers can be referred to the descriptions in the above embodiments, which will not be described here.

[0118] It should also be understood that the process of the main coordination controller distributing power to each semi-physical networked converter and each physical networked converter through the plurality of sub-coordination controllers is as follows:

[0119] First, the main coordination controller distributes the preset power instruction to each sub-coordination controller based on the preset power instruction and the proportion of the total power of the networked converter connected to each sub-coordination controller in the total power corresponding to the preset power instruction in the main coordination controller; wherein the networked converter connected to each sub-coordination controller can be a semi-physical networked converter, a physical networked converter, or a semi-physical networked converter and a physical networked converter.

[0120] Then, each sub-coordination controller determines the corresponding power instruction of the grid-forming converter connected thereto based on the operating state of the grid-forming converter connected thereto and the power instruction allocated by the main coordination controller, and sends the power instruction to the controller of the corresponding grid-forming converter. The specific process of each sub-coordination controller determining the corresponding power instruction of the grid-forming converter connected thereto based on the operating state of the grid-forming converter connected thereto and the power instruction allocated by the main coordination controller can refer to the process of the coordination controller calculating the real-time power instruction of the semi-physical grid-forming converter and the physical grid-forming converter. It can be known that, in the case that the rated capacity and the operating state of the grid-forming converter are the same, the real-time power instruction of each grid-forming converter is obtained by dividing the allocated power instruction obtained by the sub-coordination controller by the sum of the equivalent multiples of all grid-forming converters connected. In the case that the rated capacity of each grid-forming converter is different, the real-time power instruction of each grid-forming converter is obtained by dividing the product of the allocated power instruction obtained by the sub-coordination controller and the rated capacity of the corresponding converter by the sum of the product of the equivalent multiples of all grid-forming converters connected and the rated capacity of the corresponding converter. The allocated power instruction obtained by the sub-coordination controller includes the allocated active power instruction and the allocated reactive power instruction.

[0121] It can be understood that the architecture of the main coordination controller and the plurality of sub-coordination controllers can significantly improve the stability, efficiency and reliability of the power system, while providing flexible control and management capabilities to adapt to the complex needs of the power system.

[0122] In some embodiments, the test system further comprises:

[0123] The direct current power supply is connected to the direct current side of the physical grid-forming converter, and is used to provide a second electrical signal to the direct current side of the physical grid-forming converter.

[0124] It can be understood that the direct current power supply is used to provide a direct current voltage for the physical grid-forming converter. The direct current power supply can be a power electronic converter or a battery system. When the direct current power supply is a power electronic converter, the power electronic converter can simulate the output characteristics of a photovoltaic cell panel or an energy storage battery. The second electrical signal can include at least one of a direct current voltage and a direct current.

[0125] Referring to Figure 6 , a schematic diagram of a control method of a test system of a grid-forming converter accessing a complex power system is shown. Figure 6

[0126] The application further provides a control method of a test system of a grid-forming converter accessing a complex power system, which comprises:

[0127] ​start the real-time simulation module, the real-time simulation module is configured to build the preset complex power system model and the semi-physical networked converter primary system model connected with each other, and output the modulation signal based on the preset complex power system model, the semi-physical alternating current signal and the physical alternating current signal;

[0128] start the semi-physical networked converter controller, the semi-physical networked converter controller is configured to control the semi-physical networked converter primary system model, so that the semi-physical networked converter primary system model outputs the semi-physical alternating current signal to the preset complex power system model;

[0129] start the controllable converter, the controllable converter is configured to modulate based on the modulation signal to output the first electrical signal to the alternating current port of the physical networked converter;

[0130] start the physical networked converter, the physical networked converter is configured to output the physical alternating current signal of the alternating current port to the preset complex power system model;

[0131] The preset complex power system model comprises complex power models in each preset operating state; the real-time simulation module outputs the modulation signal corresponding to the complex power model in each preset operating state based on the complex power model in each preset operating state, the semi-physical alternating current signal and the physical alternating current signal.

[0132] It should be understood that the test system based on the networked converter accessing the complex power system, the control method of the test system can be specifically as follows:

[0133] S1: start the real-time simulation module, provide the converter voltage, current, switch state and other signals for the semi-physical networked converter controller, and provide the modulation voltage signal for the controllable converter;

[0134] S2: start the controllable converter, modulate based on the modulation signal to provide the alternating current voltage for the physical networked converter.

[0135] S3: start the physical networked converter, output the physical alternating current signal of the alternating current port to the preset complex power system model; wherein the starting of the physical networked converter can be based on starting the direct current power supply to provide the direct current voltage for the physical networked converter.

[0136] It should be noted that the startup of the semi-physical network type converter and the physical network type converter can be controlled based on a startup coordination controller, and the coordination controller is used to determine the power instructions corresponding to the semi-physical network type converter and the physical network type converter respectively, and send the power instructions to the corresponding semi-physical network type converter controller and the controller of the physical network type converter, so as to control the output power of the semi-physical network type converter and the physical network type converter. It should also be noted that the control method of the test system in the present application is not limited by the order of S1 to S3, and can be performed in different order in actual execution.

[0137] Further, the startup of the test system is realized based on the above S1 to S3 processes, so that the performance test of the measured network type converter can be performed, and the process of the performance test can be:

[0138] Adjusting the operation state of the preset complex power system model to test the response characteristics of the semi-physical network type converter and the physical network type converter and the influence characteristics on the preset complex power system.

[0139] The method for adjusting the operation state of the complex power system includes switching new energy, adjusting new energy wind speed / illumination intensity, switching load, adjusting load size, switching synchronous generator, adjusting synchronous generator output, switching transformer, switching AC line, adjusting line parameter, switching fault, switching network type converter, etc. Among them, the fault includes three-phase fault, two-phase fault, phase-to-phase fault and single-phase fault, the fault mode includes metal fault and non-metal fault, and the fault point can be set at any position of the complex power system. Further, the present application can provide complete network characteristic test content and system level characteristic test content. For the test content, at least one of the voltage and current data at the port of the physical network type converter can be collected, and at least one of the active power, reactive power, active current, reactive current, voltage amplitude, voltage peak value, current peak value and other data of the port of the physical network type converter can be calculated, so as to represent the performance of the physical network type converter under the corresponding test content through the collected or calculated data, and further represent the performance of the measured network type converter under the complex power system.

[0140] Please refer to Figure 7 as shown, Figure 7 The semi-physical and physical network type converters provided by the embodiments of the present application are complex power system topology diagrams when the energy storage converter is accessed.

[0141] For example, the preset complex power system can include a photovoltaic power station, a wind power station, an energy storage station, a conventional power station, a load system, a system bus, a transmission line, etc. The energy storage system in the energy storage station can be a semi-physical or full-power network type energy storage converter. Figure 7In the embodiment, the topology, parameters and operating state of the preset complex power system can be flexibly adjusted according to the test requirement, so as to test the support effect and influence of the grid-connected energy storage converter on the new energy power generation system in detail from the system level.

[0142] It should be understood that the embodiment of the application also provides a control method of a test system of a grid-connected converter accessing a complex power system, which is applied to the test system of the grid-connected converter accessing the complex power system, and the control method of the test system of the grid-connected converter accessing the complex power system includes the effects of all the features of the test system of the grid-connected converter accessing the complex power system, which will not be described here.

[0143] In summary, the application provides a test system of a grid-connected converter accessing a complex power system and a control method thereof. The system includes a real-time simulation module, a semi-physical grid-connected converter controller, a physical grid-connected converter, a controllable converter, a direct current power supply and a coordination controller. The real-time simulation module is used to build and run a large-capacity complex power system model containing large-scale new energy. The semi-physical and physical grid-connected converters are connected to the system in an aggregated manner to realize large-scale hybrid simulation. The coordination controller is responsible for coordinating and controlling the semi-physical and physical grid-connected converters. In addition, the application effectively solves the problem of testing the physical grid-connected converter accessing the large-capacity complex power system, and provides a basis for the characteristic test and system-level characteristic research of the grid-connected converter. By building a large-capacity complex power system containing large-scale new energy, energy storage converters and loads in the real-time simulation module, the actual power grid characteristics are simulated to provide a real environment for the physical converter test. Through power aggregation, large-scale energy storage is closed-loop connected to effectively verify the support effect of the converter. The application provides a basis for the characteristic test and system-level characteristic research of the grid-connected converter.

[0144] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0145] The above is only a preferred embodiment of the application, and does not limit the application in any form. Although the application has been disclosed as above with the preferred embodiment, it is not intended to limit the application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the application, and any equivalent embodiments with equivalent changes, modifications and modifications made on the basis of the technical essence of the application to the above embodiments are still within the scope of the technical solution of the application.

Claims

1. A test system for grid-forming converter access to a complex power system, the test system comprising: The test system is applied to a test process of a measured grid-connected converter in a complex power system, and the test system comprises: a real-time simulation module, configured to construct a preset complex power system model and a semi-physical grid-connected converter primary system model connected with each other, and configured to output a modulation signal based on the preset complex power system model, a semi-physical alternating current signal and a physical alternating current signal; a semi-physical grid-connected converter controller connected with the semi-physical grid-connected converter primary system model to form a semi-physical grid-connected converter, the semi-physical grid-connected converter controller being configured to control the semi-physical grid-connected converter primary system model so that the semi-physical grid-connected converter primary system model outputs the semi-physical alternating current signal to the preset complex power system model; a physical grid-connected converter connected with the preset complex power system model, the physical grid-connected converter being configured to output the physical alternating current signal of an alternating current port to the preset complex power system model; a controllable converter connected with the preset complex power system model and the physical grid-connected converter respectively, the controllable converter being configured to modulate based on the modulation signal to output a first electric signal to the alternating current port of the physical grid-connected converter; wherein the semi-physical grid-connected converter and the physical grid-connected converter jointly form the measured grid-connected converter.

2. The test system of claim 1, wherein, The real-time simulation module is further configured to construct a physical grid-connected converter interface model connected with the preset complex power system model, the alternating current port of the physical grid-connected converter and the controllable converter respectively; the physical grid-connected converter interface model being configured to output the physical alternating current signal to the preset complex power system model after processing the physical alternating current signal in a first aggregation manner, and the physical grid-connected converter interface model being configured to output the modulation signal to the controllable converter.

3. The test system of claim 2, wherein, The physical alternating current signal comprises a physical alternating current signal; The physical grid-connected converter interface model comprises: an aggregation unit connected with the preset complex power system model and the alternating current port of the physical grid-connected converter respectively, the aggregation unit being configured to output the physical alternating current signal to the preset complex power system model after processing the physical alternating current signal in the first aggregation manner.

4. The test system of claim 1, wherein, The semi-physical grid-connected converter primary system model is further configured to output the semi-physical alternating current signal to the preset complex power system model after processing the semi-physical alternating current signal in a second aggregation manner.

5. The test system of claim 1, wherein, The test system further comprises: a coordination controller connected with the semi-physical grid-connected converter controller and the physical grid-connected converter respectively, the coordination controller being configured to determine power instructions corresponding to the semi-physical grid-connected converter and the physical grid-connected converter respectively based on an operating state of the semi-physical grid-connected converter, an operating state of the physical grid-connected converter and a preset power instruction, and send the power instructions to the semi-physical grid-connected converter controller and the physical grid-connected converter corresponding respectively.

6. The test system of claim 5, wherein, The coordination controller comprises a main coordination controller and a plurality of sub-coordination controllers, the main coordination controller is connected with each of the sub-coordination controllers, and any one of the sub-coordination controllers is connected with the semi-physical network-forming type converter controller and / or the physical network-forming type converter.

7. The test system of claim 1, wherein, The real-time simulation module is configured to output a modulation signal based on the preset complex power system model, the semi-physical alternating current signal and the physical alternating current signal, and the real-time simulation module comprises: constructing a preset complex power system model, the preset complex power system model comprising complex power models in each preset operating state; outputting a modulation signal corresponding to each of the complex power models in each preset operating state based on the complex power models in each preset operating state, the semi-physical alternating current signal and the physical alternating current signal.

8. The test system of claim 1, wherein, Further comprising: a direct current power supply connected to a direct current side of the physical network-forming type converter, the direct current power supply being configured to provide a second electrical signal to the direct current side of the physical network-forming type converter.

9. The test system of claim 1, wherein, The real-time simulation module comprises: a real-time simulation interface board card, the semi-physical network-forming type converter controller being connected to the semi-physical network-forming type primary system model through the real-time simulation interface board card, and the physical network-forming type converter being connected to the preset complex power system model through the real-time simulation interface board card.

10. A control method of a test system in which a meshed network type converter is connected to a complex power system, characterized by, comprising: starting a real-time simulation module, the real-time simulation module being configured to construct a preset complex power system model and a semi-physical network-forming type primary system model connected to each other, and output a modulation signal based on the preset complex power system model, a semi-physical alternating current signal and a physical alternating current signal; starting a semi-physical network-forming type converter controller, the semi-physical network-forming type converter controller being configured to control the semi-physical network-forming type primary system model, so that the semi-physical network-forming type primary system model outputs the semi-physical alternating current signal to the preset complex power system model; starting a controllable converter, the controllable converter being configured to modulate based on the modulation signal, so as to output a first electrical signal to the alternating current port of the physical network-forming type converter; starting a physical network-forming type converter, the physical network-forming type converter being configured to output a physical alternating current signal of the alternating current port to the preset complex power system model; wherein the preset complex power system model comprises complex power models in each preset operating state; the real-time simulation module outputs a modulation signal corresponding to each of the complex power models in each preset operating state based on the complex power models in each preset operating state, the semi-physical alternating current signal and the physical alternating current signal.

Images