Hybrid closed-loop control and simulation system and method for high-power converter

Abstract

The present application relates to the technical field of high-power converter port characteristic testing, and provides a hybrid closed-loop control and simulation system and method for a high-power converter. The system comprises: a simulation apparatus, connected to an alternating-current end of a high-power converter and used to simulate fluctuations in a voltage and a frequency of an alternating-current power grid and output the fluctuations to the high-power converter; a photovoltaic / battery simulator, connected to a direct-current end of the high-power converter and used to stabilize a direct-current-side voltage of the high-power converter; a digital simulation platform, separately connected to the simulation apparatus and the high-power converter and used to acquire a port voltage and current data of the high-power converter, perform modulation on the basis of the port voltage and current data, generate a modulation signal, and output same to the simulation apparatus; and an isolation transformer, separately connected to the simulation apparatus and the photovoltaic / battery simulator, so as to provide a power supply. According to the present application, the digital simulation platform is introduced into the simulation system, to implement simulation of a power system comprising new energy, so that test requirements placed on a converter can be met.

Description

Simulation system and method for hybrid closed-loop control of high-power converter TECHNICAL FIELD

[0001] The present application relates to the technical field of high-power converter port characteristic testing, in particular to a simulation system and method for hybrid closed-loop control of high-power converter. BACKGROUND

[0002] In recent years, the newly added new energy and energy storage capacity of power grid has increased exponentially, and the proportion of power electronic devices in the power grid has been increasing. In order to ensure the safe and stable operation of the power grid, it is necessary to comprehensively analyze and research the power system of the grid structure with a high proportion of new energy. Among them, the actual electrical characteristics introduced after the grid connection of large-capacity power electronic devices are particularly important.

[0003] Conventional test power supply can only test the transient performance of power conversion system (PCS) and high-power new energy converter under specific working conditions, such as observing the port characteristics of PCS under specific voltage and frequency drop conditions. However, when a large disturbance occurs in the actual system, the voltage and frequency fluctuation is not constant, and the transient characteristics are different from the working condition of fixed voltage or frequency fluctuation. When a short-circuit fault occurs in the real power grid, the voltage is not stable at a fixed drop point, especially when the proportion of new energy in the system is large, the short-circuit support characteristics during the fault have a greater impact on the voltage. The traditional grid test vehicle tests the port characteristics of the converter by setting the target voltage and frequency, which is different from the fault characteristics of the power grid. Therefore, it is of great significance to study the closed-loop simulation platform of high-power converter and introduce the real characteristics of the power grid into the test loop.

[0004] Therefore, a test system is needed to simulate the fault characteristics of the power grid to test the port characteristics of the converter. SUMMARY

[0005] In order to solve at least one of the above problems, the present application provides a simulation system and method for hybrid closed-loop control of high-power converter.

[0006] According to a first aspect of the present application, at least one embodiment of the present application provides a high-power converter hybrid closed-loop control simulation system, comprising: an analog device connected to an AC end of a high-power converter, configured to simulate voltage and frequency fluctuation of an AC power grid and output to the high-power converter; a photovoltaic / cell simulator connected to a DC end of the high-power converter, configured to stabilize a DC side voltage of the high-power converter; a digital simulation platform connected to the analog device and the high-power converter respectively, configured to collect port voltage and current data of the high-power converter, and modulate according to the port voltage and current data to generate a modulation signal and output to the analog device; and an isolation transformer connected to the analog device and the photovoltaic / cell simulator respectively to provide a power supply.

[0007] For example, in some embodiments of the present application, the analog device comprises: at least two sets of AC / DC converters, the DC sides of the at least two sets of AC / DC converters being connected to each other, wherein: one set of AC / DC converters of the at least two sets of AC / DC converters is connected to the isolation transformer to be connected to the AC power grid for power transmission; and the other set of AC / DC converters is connected to the digital simulation platform to receive the modulation signal of the digital simulation platform to simulate the voltage and frequency fluctuation of the AC power grid and output to the high-power converter.

[0008] For example, in some embodiments of the present application, the AC / DC converter connected to the isolation transformer operates in a DC voltage control mode to control the DC voltage of the AC power grid; and the AC / DC converter connected to the digital simulation platform operates in an AC voltage control mode to generate the voltage and frequency output to the high-power converter according to the modulation signal.

[0009] For example, in some embodiments of the present application, the digital simulation platform collects the port voltage and current data of the high-power converter through a voltage transformer and a current transformer; and the digital simulation platform is connected to the analog device through a high-speed data interface to transmit the modulation signal.

[0010] For example, in some embodiments of the present application, the digital simulation platform comprises: a voltage source configured to collect voltage data of the high-power converter and serve as an original input signal of the voltage source; a current source connected in parallel with the voltage source and configured to collect current data of the high-power converter and serve as an original input signal of the current source; a disturbance setting unit connected in parallel with the voltage source and configured to simulate a test grid environment of the high-power converter; and a reactance connected between the voltage source and the disturbance setting unit.

[0011] For example, in some embodiments of the present application, when the high-power converter is of the grid-connected type, the digital simulation platform takes the collected current data as the input signal of the current source and updates the modulation signal output to the simulation device in real time; when the high-power converter is of the grid-forming type, the digital simulation platform takes the collected voltage data as the input signal of the voltage source and updates the modulation signal output to the simulation device in real time.

[0012] For example, in some embodiments of the present application, the photovoltaic / cell simulator outputs the DC side voltage of the high-power converter according to the following formula: SOC real = SOC0 + (∫P) / S battery dcreal = U dc0 + K·(SOC real - SOC0)

[0013] wherein SOC real is the actual output battery capacity, SOC0 is the initial battery capacity, P is the sampled power, S battery is the battery capacity, U dcreal is the actual output DC voltage, U dc0 is the initial voltage, and K is the proportionality coefficient of the capacity and the battery voltage.

[0014] For example, in some embodiments of the present application, further comprising: a reactance connected between the simulation device and the high-power converter.

[0015] According to the second aspect of the present application, at least one embodiment of the present application provides a high-power converter hybrid closed-loop control simulation method, which is executed by the high-power converter hybrid closed-loop control simulation system according to any one of the first aspect, and the method comprises: starting the photovoltaic / cell simulator to establish the DC side voltage of the high-power converter; starting the digital simulation platform to output an initial modulation signal without any disturbance; starting the simulation device to establish the DC voltage and the initial AC voltage; the digital simulation platform collects the port voltage and current data of the high-power converter, and sets a disturbance according to the test grid environment of the high-power converter to output a new modulation signal; the simulation device simulates the fluctuation of the voltage and frequency of the AC grid according to the new modulation signal and outputs to the high-power converter; and the digital simulation platform collects the new port voltage and current data of the high-power converter.

[0016] ​For example, in some embodiments of the present application, the simulation device includes at least two sets of AC / DC converters, and the starting of the simulation device to establish a direct current voltage and an initial alternating current voltage includes: first starting an AC / DC converter of the at least two sets of AC / DC converters connected to the isolation transformer to establish a direct current voltage; and then starting an AC / DC converter of the at least two sets of AC / DC converters connected to the digital simulation platform to establish an initial alternating current voltage.

[0017] Through the above example embodiments, the simulation system and method of the high-power converter hybrid closed-loop control provided by the present application introduce a real-time digital simulation platform into the closed-loop control simulation system, accurately simulate the system characteristics of a new power system containing high-proportion new energy such as wind power and photovoltaic power, meet the testing needs of different power grids, and can realize modeling and simulation for different topologies, different disturbance forms, and systems with various proportions of new energy. In addition, the digital simulation platform can calculate the power and frequency at the grid connection point of the converter in the model in real time, modulate the simulation device in the form of a modulated wave signal with the voltage and frequency information, and act on the high-power converter port. When the high-power converter senses fluctuations in the port voltage and frequency, it spontaneously responds with new voltage and current. The high-power converter hybrid closed-loop control simulation system can maximize the applicability and practicality of simulation, connect the port of the converter to the system model, fully integrate the advantages of semi-physical simulation and field testing, and can build different system models according to the actual topology structure of the field. Not only can it flexibly simulate the large disturbance of the power grid, but also can use the full-physical way, so that the transient characteristics of the test can more truly reflect the response characteristics of the measured converter.

[0018] It should be understood that the foregoing general description and the following detailed description are only exemplary and are not limiting of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which example embodiments of the present application are shown. The following drawings described below are only some embodiments of the present application and are not limiting of the present application.

[0020] FIG. 1 shows a schematic diagram of a high-power converter hybrid closed-loop control simulation system according to an example embodiment;

[0021] FIG. 2 shows a schematic diagram of a simulation device according to an example embodiment;

[0022] FIG. 3 shows a schematic diagram of a digital simulation platform according to an example embodiment;

[0023] FIG. 4 shows a control principle diagram of a photovoltaic / cell simulator according to an example embodiment;

[0024] FIG. 5 shows a flow chart of a simulation method of the hybrid closed-loop control of the high-power converter according to an example embodiment. DETAILED DESCRIPTION

[0025] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings. Example embodiments, however, can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the example embodiments to those skilled in the art. Like reference numerals refer to like elements throughout the several views and the description.

[0026] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the embodiments of the disclosure can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In some instances, well-known structures, methods, devices, implementations, materials, and operations are not shown or described in detail.

[0027] The flow charts shown in the drawings are only exemplary and do not necessarily include all of the content and operations / steps, nor are they necessarily executed in the order described. For example, some operations / steps can be further broken down, and some operations / steps can be combined or partially combined, so the actual execution order can be changed according to actual conditions.

[0028] The terms "first", "second", and the like in the description and in the claims of the present specification and the above drawings are used to distinguish between similar objects, and are not necessarily used to describe a particular sequential order. Also, the terms "include", "have", and the like are intended to encompass the inclusion of one or more steps or units without limitation. For example, a process, a method, a system, a product, or an apparatus that includes a list of steps or units is not limited to the listed steps or units, but can optionally further include other steps or units not listed or other steps or units inherent to such processes, methods, products, or apparatus.

[0029] Those skilled in the art can understand that the modules or flows in the drawings are only schematic diagrams of example embodiments, and are not necessarily essential to implement the present disclosure, and thus should not be used to limit the protection scope of the present disclosure.

[0030] FIG. 1 shows a schematic diagram of a simulation system of the hybrid closed-loop control of the high-power converter according to an example embodiment.

[0031] As shown in FIG. 1, the simulation system of the hybrid closed-loop control of the high-power converter includes an analog device 101, a photovoltaic / cell simulator 102, a digital simulation platform 103, and an isolation transformer 104.

[0032] The simulation device 101 is connected with the AC end of the high-power converter 20, and is used to simulate the fluctuation of the voltage and frequency of the AC power grid and output to the high-power converter 20. The photovoltaic / battery simulator 102 is connected with the DC end of the high-power converter 20, and is used to stabilize the DC side voltage of the high-power converter 20. The digital simulation platform 103 is connected with the simulation device 101 and the high-power converter 20 respectively, and is used to collect the port voltage U AC1 and current I AC1 of the high-power converter 20, and to generate a modulation signal according to the port voltage and current data, and output to the simulation device 101. The isolation transformer 104 is connected with the simulation device 101 and the photovoltaic / battery simulator 102 respectively, so as to access the power grid and provide a power supply.

[0033] As shown in FIG. 2, the simulation device 101 includes at least two sets of AC / DC converters, which are used as rectifiers AC / DC and inverters DC / AC respectively. The DC sides of the at least two sets of AC / DC converters are connected with each other.

[0034] The rectifier is connected with the main grid, and serves as a DC voltage source, responsible for controlling the DC voltage of the power grid. The inverter is connected with the AC side of the high-power converter, and communicates with the digital simulation platform through the fast communication Aurora protocol, receives the voltage reference value U ref from the digital simulation platform, and modulates the reference value to simulate the fluctuation of the voltage and frequency of the AC power grid, and applies the voltage value obtained from the digital simulation platform to the AC end of the high-power converter.

[0035] One of the at least two sets of AC / DC converters is connected with the isolation transformer 104 to connect with the AC power grid, and is used to transmit power. The other set of AC / DC converters is connected with the digital simulation platform 103 to receive the modulation signal of the digital simulation platform 103, i.e., the voltage reference value mentioned above, to simulate the fluctuation of the voltage and frequency of the AC power grid, and output to the high-power converter 20.

[0036] The AC / DC converter connected with the isolation transformer 104 operates in a DC voltage control mode, and is used to control the DC voltage of the AC power grid. The AC / DC converter connected with the digital simulation platform 103 operates in an AC voltage control mode, and is used to generate a voltage and frequency output to the high-power converter 20 according to the modulation signal U ref .

[0037] According to an example embodiment, the digital simulation platform 103 is connected with the high-power converter 20 through a voltage transformer and a current transformer, i.e., a PT / CT sampling channel, to collect port voltage and current data of the high-power converter 20. The digital simulation platform 103 is connected with the simulation device 101 through a high-speed data interface, and transmits a modulated signal U ref .

[0038] FIG. 3 shows a schematic diagram of the digital simulation platform according to an example embodiment.

[0039] As shown in FIG. 3, the digital simulation platform 103 includes a voltage source 1031, a current source 1032, a disturbance setting unit 1033, and a reactance 1034.

[0040] The voltage source 1031 is configured to collect voltage data of the high-power converter 20 and serve as an original input signal of the voltage source 1031. The current source 1032 is connected in parallel with the voltage source 1031 and configured to collect current data of the high-power converter 20 and serve as an original input signal of the current source 1032. The disturbance setting unit 1033 is connected in parallel with the voltage source 1031 and configured to simulate a test power grid environment of the high-power converter 20. The reactance 1034 is connected between the voltage source 1031 and the disturbance setting unit 1033.

[0041] According to some embodiments, the digital simulation platform builds a simulation model according to an actual topology 1:1, connects an equivalent voltage source or current source of the high-power converter in the system, collects port data of the high-power converter through PT and CT, and takes real-time values of the collected voltage and current as original input signals of the voltage source or current source in the model. When the measured converter is a grid-following PCS, the high-power converter is equivalent to a current source for simulation. When the measured converter is a grid-forming PCS, the high-power converter is equivalent to a voltage source for simulation.

[0042] In the case where the high-power converter 20 is grid-following, the digital simulation platform 103 takes the collected current data as an input signal of the current source and updates a modulated signal output to the simulation device 101 in real time. In the case where the high-power converter 20 is grid-forming, the digital simulation platform 103 takes the collected voltage data as an input signal of the voltage source and updates the modulated signal output to the simulation device 101 in real time.

[0043] According to some embodiments, the disturbance setting unit 1033 builds a power grid model consistent with field parameters and architecture according to an actual topology of the power grid, and accesses new energy sources such as photovoltaic and wind turbine and load models. The present application only takes this as an example, but is not limited thereto. Different test power grid models can be accessed in the disturbance setting unit according to test requirements of the high-power converter.

[0044] After the digital simulation platform 103 is built, corresponding disturbance points of varying sizes are set in the model. When the disturbance mechanism is triggered, the output voltage of the digital simulation platform 103 will fluctuate, at which point a new reference voltage U will be generated. ref After the digital simulation platform 103 outputs the new reference voltage and frequency to the analog device 101, the high-power converter 20 will generate new voltage and current after the external loop is closed.

[0045] After the port voltage and current data of the high-power converter 20 are updated, the port voltage and current data of the corresponding voltage source / current source in the digital simulation platform 103 are also updated. The digital simulation platform 103 feeds back the updated port voltage and current data to the power grid system to determine the changes in voltage and current data of the high-power converter under fluctuations, completes the entire closed-loop feedback, and realizes the simulation test of the high-power converter 20.

[0046] As shown in Figure 4, the photovoltaic / battery simulator 102 can simulate the actual battery characteristics to control the DC side voltage of the high-power converter 20. By setting the initial voltage, initial SOC, battery capacity, the ratio coefficient K of SOC to battery voltage, and combining the sampling power, it can simulate the DC voltage fluctuation of the battery during horizontal fluctuation to a certain extent.

[0047] The photovoltaic / cell simulator outputs the DC-side voltage of the high-power converter according to the following formula: SOC real =SOC0+(∫P) / S battery U dcreal =U dc0 +K·(SOC real -SOC0)

[0048] Among them, SOC real To output the actual battery level, SOC0 is the initial battery level, P is the sampling power, and S... battery For battery capacity, U dcreal U represents the actual value of the output DC voltage. dc0 Where is the initial voltage, and K is the ratio of charge to battery voltage.

[0049] According to an example embodiment, the hybrid closed-loop control simulation system also includes a reactor 105. The reactor 105 is connected between the simulation device 101 and the high-power converter 20.

[0050] This application also provides a simulation method for hybrid closed-loop control of a high-power converter. This method is executed by the high-power converter hybrid closed-loop control simulation system described above.

[0051] Figure 5 shows a flowchart of a high-power converter hybrid closed-loop control simulation method of an exemplary embodiment.

[0052] As shown in FIG. 5, the simulation method of the hybrid closed-loop control of the high-power converter comprises steps S501-S506.

[0053] In step S501, the photovoltaic / cell simulator is started, and the DC side voltage of the high-power converter is established.

[0054] In step S502, the digital simulation platform is started, and the initial modulation signal is output without any disturbance.

[0055] In step S503, the simulation device is started, and the DC voltage and the initial AC voltage are established.

[0056] According to the example embodiment, the AC / DC converter connected with the isolation transformer in the at least two sets of AC / DC converters is started first to establish the DC voltage, and then the AC / DC converter connected with the digital simulation platform in the at least two sets of AC / DC converters is started to establish the initial AC voltage.

[0057] In step S504, the digital simulation platform collects the port voltage and current data of the high-power converter, and sets the disturbance according to the test grid environment of the high-power converter to output the new modulation signal.

[0058] The digital simulation platform sets the corresponding disturbance point in the model, and when the disturbance mechanism is triggered, the access point voltage will fluctuate, and at this time, the new modulation signal U is generated. ref .

[0059] In step S505, the simulation device simulates the fluctuation of the voltage and frequency of the AC grid according to the new modulation signal, and outputs to the high-power converter.

[0060] In step S506, the digital simulation platform collects the new port voltage and current data of the high-power converter.

[0061] The high-power converter outputs the new voltage and current data according to the fluctuation signal of the voltage and frequency output by the simulation device, the port voltage and current data of the corresponding voltage source / current source of the digital simulation platform are also updated, and the digital simulation platform feeds back the updated port voltage and current data to the grid system to determine the data change of the voltage and current of the high-power converter under fluctuation, complete the whole closed-loop feedback, and realize the simulation test of the high-power converter.

[0062] The application provides a high-power converter hybrid closed-loop control simulation system and method, which introduces a real-time digital simulation platform into the closed-loop control simulation system, realizes accurate simulation of system characteristics of a new power system containing high-proportion new energy such as wind power and photovoltaic power, meets the test requirements of different power grids, and can realize modeling and simulation of systems with different topologies, different disturbance forms and different proportions of various new energies. Moreover, the digital simulation platform can calculate the power and frequency of the grid-connected point of the converter in the model in real time, modulate the simulation device in the form of a modulated wave signal with the voltage and frequency information, and act on the high-power converter port. When the high-power converter senses fluctuations in the port voltage and frequency, it spontaneously responds with new voltage and current. The high-power converter hybrid closed-loop control simulation system can maximize the applicability and practicality of simulation, connect the port of the converter to the system model, fully integrate the advantages of semi-physical simulation and field testing, and can build different system models according to the actual topology structure of the field. Not only can the system flexibly simulate the large disturbance of the power grid, but also can use the full-physical way, so that the transient characteristics of the test can more truly reflect the response characteristics of the measured converter.

[0063] It should be clearly understood that the present application describes how to form and use specific examples, but the present application is not limited to any details of these examples. On the contrary, based on the teachings of the disclosure of the present application, these principles can be applied to many other embodiments.

[0064] In addition, it should be noted that the above figures are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present application, and are not for limiting purposes. It is easy to understand that the processes shown in the above figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be executed synchronously or asynchronously, for example, in multiple modules.

[0065] The exemplary embodiments of the present application are specifically shown and described above. It should be understood that the present application is not limited to the detailed structure, arrangement or implementation method described herein; on the contrary, the present application is intended to cover various modifications and equivalent arrangements included in the spirit and scope of the appended claims.

Claims

1. A high-power inverter hybrid closed-loop control simulation system, characterized in that, The simulation device is connected with the AC end of the high-power converter and is used for simulating the fluctuation of voltage and frequency of the AC power grid and outputting to the high-power converter. The photovoltaic / battery simulator is connected with the DC end of the high-power converter and is used for stabilizing the DC side voltage of the high-power converter. The digital simulation platform is connected with the simulation device and the high-power converter respectively, is used for collecting the port voltage and current data of the high-power converter, and is used for modulating according to the port voltage and current data, generating a modulation signal, and outputting to the simulation device. The isolation transformer is connected with the simulation device and the photovoltaic / battery simulator respectively to provide a power supply. The simulation device comprises:

2. The high power inverter hybrid closed loop control simulation system of claim 1, wherein, At least two sets of AC / DC converters, the DC sides of the at least two sets of AC / DC converters are connected with each other, wherein: One set of AC / DC converters is connected with the isolation transformer to be connected with the AC power grid for power transmission; the other set of AC / DC converters is connected with the digital simulation platform to receive the modulation signal of the digital simulation platform to simulate the fluctuation of voltage and frequency of the AC power grid and output to the high-power converter.

3. The high-power converter hybrid closed-loop control simulation system of claim 2, wherein: The AC / DC converter connected with the isolation transformer operates in a DC voltage control mode to control the DC voltage of the AC power grid; The AC / DC converter connected with the digital simulation platform operates in an AC voltage control mode to generate the voltage and frequency output to the high-power converter according to the modulation signal.

4. The high-power converter hybrid closed-loop control simulation system of claim 1, wherein: The digital simulation platform collects the port voltage and current data of the high-power converter through a voltage transformer and a current transformer; The digital simulation platform is connected with the simulation device through a high-speed data interface to transmit the modulation signal. The digital simulation platform comprises:

5. The high power inverter hybrid closed loop control simulation system of claim 1, wherein, A voltage source for collecting the voltage data of the high-power converter and taking the voltage data as the original input signal of the voltage source; A current source connected in parallel with the voltage source for collecting the current data of the high-power converter and taking the current data as the original input signal of the current source; A disturbance setting unit connected in parallel with the voltage source for simulating the test grid environment of the high-power converter; An electric reactance connected between the voltage source and the disturbance setting unit.

6. The high-power converter hybrid closed-loop control simulation system of claim 5, wherein: In the case that the high-power converter is a grid-following type, the digital simulation platform takes the collected current data as the input signal of the current source and updates the modulation signal output to the simulation device in real time; In the case that the high-power converter is a grid-forming type, the digital simulation platform takes the collected voltage data as the input signal of the voltage source and updates the modulation signal output to the simulation device in real time. Further comprising:

7. The high power inverter hybrid closed loop control simulation system of claim 1, wherein, The photovoltaic / cell simulator outputs the DC side voltage of the high-power converter according to the following formula: SOC real = SOC0 + (∫P) / S battery U dcreal = U dc0 + K · (SOC real - SOC0) SOC = SOC0 + K * (P - S) / U real wherein SOC is the output battery power actual value, SOC0 is the initial battery power, P is the sampling power, S battery is the battery capacity, U dcreal is the output DC voltage actual value, U dc0 is the initial voltage, and K is the power-to-battery voltage proportionality coefficient.

8. The high power inverter hybrid closed loop control simulation system of claim 1, wherein, ​ reactance connected between the analog device and the high-power converter.

9. A simulation method of a hybrid closed-loop control of a high-power inverter, characterized by, executed by the high-power converter hybrid closed-loop control simulation system according to any one of claims 1-8, the method comprising: starting the photovoltaic / cell simulator to establish a direct current side voltage of the high-power converter; starting the digital simulation platform to output an initial modulation signal without any disturbance; starting the analog device to establish a direct current voltage and an initial alternating current voltage; the digital simulation platform collecting port voltage and current data of the high-power converter and setting a disturbance according to a test grid environment of the high-power converter to output a new modulation signal; the analog device simulating fluctuation of voltage and frequency of an alternating current grid according to the new modulation signal and outputting to the high-power converter; the digital simulation platform collecting new port voltage and current data of the high-power converter.

10. The method of claim 9, wherein the method further comprises: the analog device comprising at least two sets of AC / DC converters, and the starting the analog device to establish a direct current voltage and an initial alternating current voltage comprising: first starting an AC / DC converter of the at least two sets of AC / DC converters connected with the isolation transformer to establish a direct current voltage; then starting an AC / DC converter of the at least two sets of AC / DC converters connected with the digital simulation platform to establish an initial alternating current voltage.

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