Test system and method for inertia of energy storage system based on semi-physical simulation platform

Abstract

The application provides a kind of inertia test system and method of energy storage system based on semi-physical simulation platform, belongs to the field of energy storage.The system includes: semi-physical simulation platform, energy storage controller and waveform recording analyzer;The analog output end of semi-physical simulation platform is connected to the input end of energy storage controller, for transmitting the generated analog signal to energy storage controller;The output end of energy storage controller is connected with the digital input end of semi-physical simulation platform, and energy storage controller is used to determine the power variation, and is transmitted to semi-physical simulation platform, and semi-physical simulation platform generates analog signal of energy storage system according to power variation update;The analog output end of semi-physical simulation platform is also connected with the input end of waveform recording analyzer, for transmitting the analog signal of energy storage system to waveform recording analyzer, and waveform recording analyzer is used to determine the test result of energy storage system inertia test project.The application can conveniently and accurately test the inertia of energy storage system.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to a testing system and method for the inertia of an energy storage system based on a hardware-in-the-loop simulation platform. Background Technology

[0002] In a power system, inertia refers to the ability to resist changes in grid frequency. Traditional power generation methods such as thermal power, hydropower, nuclear power, and natural gas power all output electrical energy through generators. When grid frequency fluctuates, the rotational inertia of the turbine units can mitigate the frequency fluctuation trend. However, wind turbine units rotate slowly and have relatively small rotational inertia, and photovoltaic power generation has no rotating equipment and therefore no rotational inertia. Consequently, their response capability decreases significantly when the grid frequency changes abruptly.

[0003] With the increasing proportion of new energy sources in the future, the rotational inertia of the power system will decrease by more than 30%. Energy storage systems can provide inertia support for the power system, supplement the frequency regulation capability of the grid, and have good response efficiency, making them an effective supplement to the inertia of power systems with a high proportion of new energy sources. Therefore, testing the inertia of energy storage systems is very important.

[0004] The relevant technologies mainly test the inertia of energy storage systems through full physical simulation. However, this method requires operators to perform high-voltage wiring and repeated operations on-site using the energy storage system. Furthermore, the inertia testing process may affect the normal operation of the energy storage system, making the inertia testing of energy storage systems difficult and complex. Summary of the Invention

[0005] This invention provides a test system and method for the inertia of an energy storage system based on a hardware-in-the-loop simulation platform, so as to conveniently and accurately test the inertia of the energy storage system.

[0006] In a first aspect, embodiments of the present invention provide a test system for the inertia of an energy storage system based on a hardware-in-the-loop simulation platform, including a hardware-in-the-loop simulation platform, an energy storage controller, and a waveform recording and analysis instrument;

[0007] The analog output terminal of the hardware-in-the-loop simulation platform is connected to the input terminal of the energy storage controller, and is used to transmit the generated analog signal to the energy storage controller.

[0008] The output terminal of the energy storage controller is connected to the digital input terminal of the hardware-in-the-loop simulation platform. The energy storage controller is used to determine the power change based on the inertia time constant of the energy storage system and the received analog signal, and transmit it to the hardware-in-the-loop simulation platform. The hardware-in-the-loop simulation platform updates the generated analog signal based on the power change to obtain the analog signal simulating the energy storage system.

[0009] The analog output terminal of the hardware-in-the-loop simulation platform is also connected to the input terminal of the waveform recording and analysis instrument, which is used to transmit the analog signal of the energy storage system to the waveform recording and analysis instrument. The waveform recording and analysis instrument determines the test result of the inertia test item of the energy storage system based on the frequency disturbance signal and the analog signal of the energy storage system; wherein, the frequency disturbance signal is determined based on the inertia test item.

[0010] In one possible implementation, the hardware-in-the-loop simulation platform is further used to determine the frequency disturbance signal based on the inertia test item;

[0011] The energy storage controller is used to determine the power change based on the inertia time constant of the energy storage system, the received analog signal, and the frequency disturbance signal.

[0012] In one possible implementation, the test system further includes a frequency signal source;

[0013] The output terminal of the frequency signal source is connected to the input terminal of the energy storage controller, and is used to determine the frequency disturbance signal according to the inertia test item, and transmit the frequency disturbance signal to the energy storage controller. The energy storage controller determines the power change based on the inertia time constant, the received analog signal and the frequency disturbance signal.

[0014] The output of the frequency signal source is also connected to the input of the waveform recording and analysis instrument, for sending the frequency disturbance signal to the waveform recording and analysis instrument.

[0015] In one possible implementation, the energy storage controller, after determining the power change based on the inertia time constant of the energy storage system and the received analog signal, is further configured to:

[0016] Determine whether the power change is less than a preset threshold;

[0017] If the power change is less than the preset threshold, the inertia time constant is updated, and the power change is re-determined until the re-determined power change is equal to or greater than the preset threshold.

[0018] In one possible implementation, the energy storage controller updates the inertia time constant by:

[0019] According to the expression: T Ji+1 =T Ji +10%T Ji Update the inertia time constant;

[0020] In the formula, T Ji+1 T represents the inertia time constant after the (i+1)th update. JiLet represent the inertia time constant after the i-th update, where i = 1, 2, 3, ...

[0021] In one possible implementation, the inertia test item includes an inertia response dead zone test.

[0022] Determining the frequency disturbance signal based on the inertia test item includes:

[0023] Calculate the difference between the inertial response dead zone and the control accuracy of the energy storage controller, and the sum of the inertial response dead zone and the control accuracy of the energy storage controller.

[0024] The frequency signal corresponding to the inertial response dead zone, the frequency signal corresponding to the difference, and the frequency signal corresponding to the sum are used as the frequency disturbance signal.

[0025] In one possible implementation, the inertia test item includes a frequency disturbance test, wherein the frequency disturbance signal includes a frequency disturbance upper disturbance signal and a frequency disturbance lower disturbance signal;

[0026] Determining the frequency disturbance signal based on the inertia test item includes:

[0027] Determine the frequency disturbance change rate corresponding to the frequency disturbance signal in the frequency disturbance test, wherein the frequency disturbance change rate is greater than the inertial response dead zone of the energy storage system;

[0028] The frequency signal that is increased to a preset first upscratching frequency at the frequency perturbation rate and then decreased to the preset frequency at the frequency perturbation rate after being held at the first upscratching frequency for a first preset time is used as the frequency perturbation upscratching signal.

[0029] The frequency signal that decreases from the preset frequency to a preset first downscrambling frequency at the frequency perturbation rate, and then increases back to the preset frequency at the frequency perturbation rate after maintaining the first downscrambling frequency for a first preset time, is used as the frequency perturbation downscrambling signal.

[0030] In one possible implementation, the inertia test item includes a primary frequency modulation coordination test, and the frequency disturbance signal includes a primary frequency modulation upscratching signal and a primary frequency modulation downscratching signal;

[0031] Determining the frequency disturbance signal based on the inertia test item includes:

[0032] Determine the primary frequency modulation change rate and primary frequency modulation change amount corresponding to the frequency disturbance signal in the primary frequency modulation coordination test. The primary frequency modulation change rate is greater than the inertia response dead zone of the energy storage system, and the primary frequency modulation change amount is greater than the frequency change dead zone of the energy storage system.

[0033] Based on the first frequency modulation change, determine the second upper scrambling frequency and the second lower scrambling frequency corresponding to the preset frequency;

[0034] The frequency signal that is raised to the second upscrambling frequency at the first frequency modulation rate and then lowered to the preset frequency at the first frequency modulation rate after maintaining the second upscrambling frequency for a second preset time is used as the first frequency modulation upscrambling signal.

[0035] The frequency signal that decreases from the preset frequency to the second downscrambling frequency at the first frequency modulation rate, and then increases back to the preset frequency at the first frequency modulation rate after maintaining the second downscrambling frequency for a second preset time, is used as the first frequency modulation downscrambling signal.

[0036] In one possible implementation, after the waveform recording analyzer determines the test result of the energy storage system inertia test item based on the frequency disturbance signal and the analog signal of the energy storage system, the waveform recording analyzer is further configured to:

[0037] According to the expression: Determine the actual inertia time constant of the energy storage system;

[0038] In the formula, T J ΔP represents the actual inertia time constant of the energy storage system. I f represents the power change of the energy storage system. N Indicates the rated frequency. P represents the rate of change of frequency. N This indicates the rated active power of the energy storage system.

[0039] Secondly, embodiments of the present invention provide a method for testing the inertia of an energy storage system based on a hardware-in-the-loop simulation platform. The method is applied to the hardware-in-the-loop simulation platform and includes:

[0040] The generated analog signal is transmitted to the energy storage controller, so that the energy storage controller determines the power change based on the inertia time constant of the energy storage system and the received analog signal, and transmits it to the hardware-in-the-loop simulation platform.

[0041] The analog signal generated based on the power change is used to obtain the analog signal simulating the energy storage system, and the analog signal of the energy storage system is transmitted to the waveform recording and analysis instrument so that the waveform recording and analysis instrument can determine the test result of the inertia test item of the energy storage system based on the frequency disturbance signal and the analog signal of the energy storage system; wherein, the frequency disturbance signal is determined according to the inertia test item.

[0042] The beneficial effects of the embodiments of the present invention compared with the prior art are as follows:

[0043] This invention establishes a test system for the inertia of an energy storage system using a hardware-in-the-loop (HIL) platform, an energy storage controller, and a waveform recording and analysis instrument. The HIL generates a simulated signal for the energy storage system and transmits it to the energy storage controller. The energy storage controller adjusts the power based on the inertia time constant and the received simulated signal, determines the power change, and transmits it back to the HIL. The HIL then updates the generated simulated signal based on the power change and transmits it to the waveform recording and analysis instrument. Finally, the waveform recording and analysis instrument uses a frequency disturbance signal and the received simulated signal to determine the test results for the energy storage system's inertia test, thereby obtaining the inertia response of the energy storage system and enabling accurate testing of the energy storage system's inertia. Furthermore, inertia testing via the HIL eliminates the need for direct testing of the energy storage system, avoiding high-voltage wiring by operators on-site and improving the safety and convenience of the test. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the structure of an energy storage system inertia test system based on a hardware-in-the-loop simulation platform provided in an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the workflow of a test system for the inertia of an energy storage system based on a hardware-in-the-loop simulation platform, provided in an embodiment of the present invention.

[0047] Figure 3 This is a schematic diagram of another energy storage system inertia testing system based on a hardware-in-the-loop simulation platform provided in an embodiment of the present invention;

[0048] Figure 4 This is a flowchart illustrating the optimization of the inertia time constant provided in an embodiment of the present invention;

[0049] Figure 5(a) is a frequency waveform diagram of an inertial response dead zone test provided in an embodiment of the present invention;

[0050] Figure 5(b) is a frequency waveform diagram of another inertial response dead zone test provided in an embodiment of the present invention;

[0051] Figure 5(c) is a frequency waveform diagram of the inertial response dead zone test provided in the embodiment of the present invention;

[0052] Figure 6(a) is a waveform diagram corresponding to the frequency upsampling in the charging state provided by the embodiment of the present invention;

[0053] Figure 6(b) is a waveform diagram corresponding to the frequency upsampling under the discharge state provided in the embodiment of the present invention;

[0054] Figure 6(c) is a waveform diagram corresponding to frequency scrambling in the charging state provided by the embodiment of the present invention;

[0055] Figure 6(d) is a waveform diagram corresponding to frequency perturbation under the discharge state provided in the embodiment of the present invention;

[0056] Figure 7(a) is a schematic diagram of the primary frequency modulation rate provided in an embodiment of the present invention;

[0057] Figure 7(b) is a schematic diagram of the primary frequency modulation start signal provided in an embodiment of the present invention;

[0058] Figure 7(c) is a schematic diagram comparing the primary frequency modulation scrambling signal and the frequency modulation amount provided in the embodiment of the present invention;

[0059] Figure 7(d) is a comparative schematic diagram of the primary frequency modulation scrambling signal, frequency modulation command and active power provided in the embodiment of the present invention;

[0060] Figure 8 This is a flowchart illustrating the implementation of a method for testing the inertia of an energy storage system based on a hardware-in-the-loop simulation platform, as provided in an embodiment of the present invention. Detailed Implementation

[0061] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0062] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0063] Figure 1 A schematic diagram of a test system for the inertia of an energy storage system based on a hardware-in-the-loop simulation platform, provided in an embodiment of the present invention, is shown below. Figure 1 As shown, the system 10 includes a hardware-in-the-loop simulation platform 11, an energy storage controller 12, and a waveform recording and analysis instrument 13;

[0064] The analog output terminal AO of the hardware-in-the-loop simulation platform 11 is connected to the input terminal of the energy storage controller 12 to transmit the generated analog signal to the energy storage controller 12.

[0065] The output terminal of the energy storage controller 12 is connected to the digital input terminal DI of the hardware-in-the-loop simulation platform 11. The energy storage controller 12 is used to determine the power change based on the inertia time constant of the energy storage system and the received analog signal, and transmit it to the hardware-in-the-loop simulation platform 11. The hardware-in-the-loop simulation platform 11 updates the generated analog signal based on the power change to obtain the analog signal of the simulated energy storage system.

[0066] The analog output terminal AO of the hardware-in-the-loop simulation platform 11 is also connected to the input terminal of the waveform recording and analysis instrument 13, which is used to transmit the analog signal of the energy storage system to the waveform recording and analysis instrument 13. The waveform recording and analysis instrument 13 determines the test results of the inertia test item of the energy storage system based on the frequency disturbance signal and the analog signal of the energy storage system; wherein, the frequency disturbance signal is determined according to the inertia test item.

[0067] In this embodiment, the hardware-in-the-loop simulation platform 11 can simulate and generate various analog signals of the energy storage system, including voltage signals, current signals, and power signals. These analog signals are then transmitted to the energy storage controller 12 and the waveform recording and analysis instrument 13 for subsequent simulation testing and result analysis.

[0068] The energy storage controller 12 modulates and varies the response based on the inertia time constant of the energy storage system and the analog signal to determine the power change of the energy storage system, thereby achieving the inertia response of the energy storage system. For example, the energy storage controller 12 can control the power change by outputting pulse width modulation (PWM), that is, transmitting the generated PWM signal to the hardware-in-the-loop (HILL) simulation platform 11 to control and update the analog signal of the HILL simulation platform 11, thus achieving the inertia response in the energy storage system. Here, the power change refers to the change in active power.

[0069] The hardware-in-the-loop simulation platform 11 also transmits the updated analog signal to the waveform recording and analysis instrument 13 for waveform recording and analysis. The waveform recording and analysis instrument 13 can record the frequency disturbance signal corresponding to the inertia test item, as well as the analog signal corresponding to the frequency disturbance signal. It can obtain the changes in voltage, current and power of the energy storage system under different frequency changes, and then analyze and determine the test results of the inertia test of the energy storage system.

[0070] Here, the energy storage system mainly refers to the energy storage system under test. The simulated signals generated by the hardware-in-the-loop simulation platform are the voltage, current, and power signals corresponding to the energy storage system under test. Inertia testing items for energy storage systems can include inertia response dead zone testing, frequency disturbance testing, and primary frequency regulation coordination testing, etc.

[0071] Optionally, the hardware-in-the-loop simulation platform 11 is also used to determine the frequency disturbance signal based on the inertia test items;

[0072] The energy storage controller 12 is used to determine the power change based on the inertia time constant of the energy storage system, the received analog signal, and the frequency disturbance signal.

[0073] In this embodiment, the hardware-in-the-loop simulation platform 11 can generate analog signals such as voltage signals, current signals and power signals, as well as frequency disturbance signals. The frequency in the frequency disturbance signal can be changed according to the needs of the inertia test project to achieve the test of the inertia of the energy storage system.

[0074] The frequency disturbance signal generated by the hardware-in-the-loop simulation platform 11 is also an analog signal. The frequency disturbance signal can be transmitted to the energy storage controller 12 and the waveform recording and analysis instrument 13 along with the voltage signal, current signal, and power signal. Correspondingly, the energy storage controller 12 will also receive the frequency disturbance signal and determine the corresponding power change based on the frequency disturbance signal to perform inertia response of the energy storage system and realize inertia testing.

[0075] This invention establishes a test system for the inertia of an energy storage system using a hardware-in-the-loop (HIL) platform, an energy storage controller, and a waveform recording and analysis instrument. The HIL generates a simulated signal for the energy storage system and transmits it to the energy storage controller. The energy storage controller adjusts the power based on the inertia time constant and the received simulated signal, determines the power change, and transmits it back to the HIL. The HIL then updates the generated simulated signal based on the power change and transmits it to the waveform recording and analysis instrument. Finally, the waveform recording and analysis instrument uses a frequency disturbance signal and the received simulated signal to determine the test results for the energy storage system's inertia test, thereby obtaining the inertia response of the energy storage system and enabling accurate testing of the energy storage system's inertia. Furthermore, inertia testing via the HIL eliminates the need for direct testing of the energy storage system, avoiding high-voltage wiring by operators on-site and improving the safety and convenience of the test.

[0076] In one embodiment, Figure 2 A schematic diagram of the workflow of a test system for the inertia of an energy storage system based on a hardware-in-the-loop simulation platform is shown, illustrating the information interaction between the hardware-in-the-loop simulation platform 11, the energy storage controller 12, and the waveform recording and analysis instrument 13, including:

[0077] Step 201: The hardware-in-the-loop simulation platform 11 generates analog signals and frequency perturbation signals. The frequency perturbation signals are determined based on the inertia test items.

[0078] Step 202: The hardware-in-the-loop simulation platform 11 transmits the generated analog signal and frequency disturbance signal to the energy storage controller 12, and at the same time transmits the analog signal and frequency disturbance signal to the waveform recording and analysis instrument 13.

[0079] Step 203: The energy storage controller 12 determines the power change based on the inertia time constant of the energy storage system, the received analog signal, and the frequency disturbance signal.

[0080] Step 204: The energy storage controller 12 transmits the power change to the hardware-in-the-loop simulation platform 11.

[0081] Step 205: The hardware-in-the-loop simulation platform 11 updates the generated simulation signal according to the power change to obtain the simulation signal of the simulated energy storage system.

[0082] Step 206: The hardware-in-the-loop simulation platform 11 transmits the analog signals of the energy storage system to the waveform recording and analysis instrument 13.

[0083] Step 207: The waveform recording and analysis instrument 13 determines the test results of the energy storage system inertia test item based on the frequency disturbance signal and the analog signal of the energy storage system.

[0084] The specific implementation process and principle of this embodiment can be found in [reference]. Figure 1 The specific description of the illustrated embodiment will not be repeated here.

[0085] In one embodiment, see Figure 3 The diagram shows another structural schematic of an energy storage system inertia test system based on a hardware-in-the-loop simulation platform. The test system 10 also includes a frequency signal source 14.

[0086] The output of the frequency signal source 14 is connected to the input of the energy storage controller 12. It is used to determine the frequency disturbance signal according to the inertia test items and transmit the frequency disturbance signal to the energy storage controller 12. The energy storage controller 12 determines the power change based on the inertia time constant, the received analog signal and the frequency disturbance signal.

[0087] The output of the frequency signal source 14 is also connected to the input of the waveform recording and analysis instrument 13, which is used to send the frequency disturbance signal to the waveform recording and analysis instrument 13.

[0088] In this embodiment, considering that some hardware-in-the-loop simulation platforms 11 may not be able to generate frequency disturbance signals of frequency change on their own, a frequency signal source 14 can be connected to the test system 10 in this case to generate the frequency disturbance signal required for the inertia test of the energy storage system, so as to ensure that subsequent processing can proceed normally.

[0089] For example, the frequency disturbance signal can be set using the following parameters:

[0090] Starting frequency: The starting point of frequency change, that is, the three-phase voltage frequency in the initial state.

[0091] Cutoff frequency: The end point of frequency change, that is, the three-phase voltage frequency at the end state.

[0092] Return (Termination) Frequency: The frequency at which the state change ends.

[0093] Rate of change of frequency The rate of change of frequency.

[0094] Initial state: Set the amplitude, angle, and frequency of the three-phase voltage.

[0095] End state: Set the amplitude, angle, and frequency of the three-phase voltage.

[0096] In one possible implementation, see Figure 4 As shown, after determining the power change based on the inertia time constant of the energy storage system and the received analog signal, the energy storage controller 12 is also used for:

[0097] Determine whether the power change is less than a preset threshold;

[0098] If the power change is less than a preset threshold, the inertia time constant is updated, and the power change is redefined until the redefined power change is equal to or greater than the preset threshold. Here, the energy storage controller 12 can preset the initial value of the inertia time constant, and update the initial value of the inertia time constant when the power change is less than the preset threshold.

[0099] In this embodiment, during inertial response, the change in active power of the energy storage system should not be less than 10% of the rated active power. Therefore, after determining the power change of the energy storage system, the power change can be further determined and corrected to ensure that the inertial time constant of the corresponding energy storage system meets the above-mentioned inertial response requirements. Simultaneously, after correcting the inertial time constant, the corrected inertial time constant can be directly set into the corresponding energy storage system under test, thereby optimizing the inertia of the energy storage system.

[0100] Here, the energy storage controller 12 is equipped with relevant data on the inertia time constant of the energy storage system under test. When determining the power change for the first time, the power change can be determined based on the inertia time constant of the energy storage system under test.

[0101] Optionally, it can be based on the expression: Determine the amount of power change.

[0102] In the formula, ΔP I T represents the power change of an energy storage system. J This represents the inertia time constant of the energy storage system, which is typically 4s-14s. N Indicates the rated frequency. P represents the rate of change of frequency. N This indicates the rated active power of the energy storage system.

[0103] Optionally, the energy storage controller updates the inertia time constant, including:

[0104] According to the expression: T Ji+1 =T Ji +10%T Ji Update the inertia time constant;

[0105] In the formula, T Ji+1 T represents the inertia time constant after the (i+1)th update. Ji Let represent the inertia time constant after the i-th update, where i = 1, 2, 3, ...

[0106] In this embodiment, the inertia time constant of the energy storage system under test set in the energy storage controller 12 is the initial inertia time constant, i.e., T. J0 .

[0107] When performing the initial inertia time constant calculation, it can be updated using the following formula:

[0108] T J1 =T J0 +10%T J0 ;

[0109] In the formula, T J1 T represents the inertia time constant after the first update in the energy storage controller. J0 This represents the inertia time constant initially set in the energy storage controller.

[0110] In one possible implementation, the inertia testing program includes inertia response dead zone testing.

[0111] This embodiment determines the frequency disturbance signal based on the inertia test items, including:

[0112] Calculate the difference between the inertial response dead zone and the control accuracy of the energy storage controller, and the sum of the inertial response dead zone and the control accuracy of the energy storage controller.

[0113] The frequency signals corresponding to the inertial response dead zone, the frequency signals corresponding to the difference, and the frequency signals corresponding to the sum of these are used as frequency disturbance signals.

[0114] In this embodiment, when the frequency signal changes at a rate of change greater than or equal to the inertial response dead zone, the energy storage system will take corresponding actions to achieve inertial response; when the frequency signal changes at a rate of change less than the inertial response dead zone, the energy storage system will not take any action. Therefore, based on the aforementioned changes in the rate of change of frequency, an inertial response dead zone test can be performed on the energy storage controller using a frequency disturbance signal.

[0115] For example, referring to the frequency waveform diagram of one inertial response dead zone test shown in Figure 5(a), the frequency waveform diagram of another inertial response dead zone test shown in Figure 5(b), and the frequency waveform diagram of yet another inertial response dead zone test shown in Figure 5(c), the inertial response dead zone of the tested energy storage system is 0.1Hz / s, and the control accuracy of the energy storage controller is 0.1Hz / s. Therefore, in the inertial response dead zone test, the frequency change rate in the frequency disturbance signal is set to 0.1Hz / s, 0.11Hz / s, and 0.09Hz / s, respectively.

[0116] As shown in Figure 5(a), when the frequency change rate is 0.1 Hz / s, the primary frequency modulation start signal operates frequently, meaning the energy storage controller frequently performs inertial response. As shown in Figure 5(b), when the frequency change rate is 0.11 Hz / s, the primary frequency modulation start signal operates normally, meaning the energy storage controller performs inertial response when the frequency disturbance signal begins to change according to the frequency change rate. As shown in Figure 5(c), when the frequency change rate is 0.09 Hz / s, the primary frequency modulation start signal does not operate, meaning the energy storage controller does not perform inertial response during the frequency disturbance signal change process.

[0117] In one possible implementation, the inertia test includes a frequency disturbance test, and the frequency disturbance signal includes a frequency disturbance upsampling signal and a frequency disturbance downsampling signal.

[0118] This embodiment determines the frequency disturbance signal based on the inertia test items, including:

[0119] Determine the rate of change of frequency disturbance corresponding to the frequency disturbance signal in the frequency disturbance test, where the rate of change of frequency disturbance is greater than the aforementioned inertial response dead zone;

[0120] The frequency signal that is raised to a preset first upscratching frequency at a preset frequency perturbation rate and then lowered to a preset frequency at a frequency perturbation rate after maintaining the first upscratching frequency for a first preset time is used as the frequency perturbation upscratching signal.

[0121] The frequency signal that decreases to a preset first downscrambling frequency at a frequency perturbation rate and then increases to the preset frequency at a frequency perturbation rate after maintaining the first downscrambling frequency for a first preset time is used as the frequency perturbation downscrambling signal.

[0122] In this embodiment, based on the analysis of the embodiments corresponding to Figures 5(a), 5(b), and 5(c), it can be seen that when the frequency change rate is greater than the corresponding dead zone of inertia, the energy storage controller will perform an inertial response to perform a first-order frequency modulation. Therefore, when conducting frequency disturbance tests, the frequency disturbance change rate corresponding to the frequency disturbance signal needs to be greater than the corresponding dead zone of inertia to enable the energy storage controller to perform an inertial response. For example, the frequency disturbance change rate can be 0.15Hz / s, 0.2Hz / s, 0.3Hz / s, etc.

[0123] Referring to Figure 6(a), the waveforms corresponding to frequency upsampling during the charging state are shown. The upper waveforms represent the frequency upsampling signal, which shows a trend of first rising, then leveling off, and finally falling. Referring to Figure 6(c), the waveforms corresponding to frequency downsampling during the charging state are shown. The upper waveforms represent the frequency downsampling signal, which shows a trend of first falling, then leveling off, and finally rising. The energy storage controller will perform an inertial response when the frequency of the frequency disturbance signal changes; that is, the energy storage controller will perform an inertial response when the frequency rises or falls.

[0124] Here, the preset frequency can be the three-phase voltage frequency of the power system, such as 50Hz. The preset first upper disturbance frequency can be 50.2Hz, 50.3Hz, 50.4Hz, etc., and the preset first lower disturbance frequency can be 49.8Hz, 49.7Hz, 49.6Hz, etc., which can be set as needed to achieve frequency disturbance test. The first preset time can be 8s, 10s, 12s, 15s, etc.

[0125] For example, this embodiment can simulate the charging and discharging operation states of an energy storage system by configuring a hardware-in-the-loop simulation platform and an energy storage controller, and conduct frequency disturbance tests under different operation states. Here, the active power of the energy storage system is 3000kW; the frequency disturbance upper disturbance signal rises from 50Hz to 50.2Hz at a frequency disturbance change rate of 0.2Hz / s, is maintained for 10s, and then decreases back to 50Hz at a frequency disturbance change rate of 0.2Hz / s; the frequency disturbance lower disturbance signal decreases from 50Hz to 49.8Hz at a frequency disturbance change rate of 0.2Hz / s, is maintained for 10s, and then rises back to 50Hz at a frequency disturbance change rate of 0.2Hz / s.

[0126] Accordingly, Figure 6(a) shows the waveform corresponding to the frequency up-disturbance during charging, Figure 6(b) shows the waveform corresponding to the frequency up-disturbance during discharging, Figure 6(c) shows the waveform corresponding to the frequency down-disturbance during charging, and Figure 6(d) shows the waveform corresponding to the frequency down-disturbance during discharging. In each of Figures 6(a), 6(b), 6(c), and 6(d), there are two waveforms: the upper waveform represents the frequency perturbation signal, and the lower waveform represents the active power.

[0127] Therefore, when the rate of change of frequency disturbance exceeds the dead zone of inertial response, the energy storage system will perform inertial response in both charging and discharging states. Furthermore, the direction of power change of the energy storage system is negatively correlated with the direction of the rate of change of frequency disturbance, which can play a role in delaying rapid frequency changes.

[0128] In one possible implementation, the inertia test item includes a primary frequency modulation coordination test, and the frequency disturbance signal includes a primary frequency modulation upscramble signal and a primary frequency modulation downscramble signal.

[0129] In this embodiment, when determining the frequency disturbance signal based on the inertia test item, the first step is to determine the first-order frequency modulation change rate and the first-order frequency modulation change amount corresponding to the frequency disturbance signal in the first-order frequency modulation coordination test. The first-order frequency modulation change rate is greater than the aforementioned inertia response dead zone, and the first-order frequency modulation change amount is greater than the aforementioned frequency change amount dead zone. Then, based on the first-order frequency modulation change amount, the second upper disturbance frequency and the second lower disturbance frequency corresponding to the preset frequency are determined. The preset frequency is then increased to the second upper disturbance frequency with the first-order frequency modulation change rate, and after maintaining the second upper disturbance frequency for a second preset time, the frequency signal is decreased to the preset frequency with the first-order frequency modulation change rate. This frequency signal is used as the first-order frequency modulation upper disturbance signal. Similarly, the preset frequency is decreased to the second lower disturbance frequency with the first-order frequency modulation change rate, and after maintaining the second lower disturbance frequency for a second preset time, the frequency signal is increased to the preset frequency with the first-order frequency modulation change rate. This frequency signal is used as the first-order frequency modulation lower disturbance signal.

[0130] In this embodiment, based on the analysis of the embodiments corresponding to Figures 5(a), 5(b), and 5(c), it can be seen that when the frequency change rate is greater than the corresponding dead zone of inertia, the energy storage controller will perform an inertial response to perform primary frequency modulation. Therefore, during the primary frequency modulation coordination test, the primary frequency modulation change rate corresponding to the frequency disturbance signal needs to be greater than the corresponding dead zone of inertia to enable the energy storage controller to perform an inertial response. For example, the primary frequency modulation change rate can be 0.15Hz / s, 0.2Hz / s, 0.3Hz / s, etc.

[0131] It is important to note that the primary frequency modulation change is the change in frequency within the frequency disturbance signal, such as the difference between the preset frequency and the second upper disturbance frequency, or the difference between the preset frequency and the second lower disturbance frequency. In primary frequency modulation coordination tests, the primary frequency modulation change must be greater than the frequency change dead zone.

[0132] Referring to Figure 7(a), which shows the schematic diagram of the primary frequency modulation rate of change, Figure 7(a) actually corresponds to the primary frequency modulation scrambling signal. At 0s, the primary frequency modulation rate of change is 0, and the frequency of the corresponding primary frequency modulation scrambling signal does not change (it is the preset frequency). At about 10s, the primary frequency modulation rate of change is -0.2Hz / s, and the frequency of the corresponding primary frequency modulation scrambling signal begins to decrease and continues until about 20s. At about 20s, the primary frequency modulation rate of change returns to 0, and the frequency of the corresponding primary frequency modulation scrambling signal decreases to the second scrambling frequency. From about 20s to 25s, the primary frequency modulation rate of change remains 0, and the frequency of the corresponding primary frequency modulation scrambling signal remains at the second scrambling frequency. At about 25s, the primary frequency modulation rate of change is 0.2Hz / s, and the frequency of the corresponding primary frequency modulation scrambling signal begins to rise and continues until about 35s. At about 35s, the primary frequency modulation rate of change returns to 0, and the frequency of the corresponding primary frequency modulation scrambling signal rises to the preset frequency.

[0133] Referring to the schematic diagram of the primary frequency modulation start signal shown in Figure 7(b), when the frequency disturbance signal begins to change, that is, when the frequency of the frequency disturbance signal deviates from the preset frequency, the primary frequency modulation start signal is activated to start primary frequency modulation; when the frequency disturbance signal returns to the preset frequency, the primary frequency modulation start signal also returns to 0, and primary frequency modulation ends.

[0134] Referring to Figure 7(c), which shows a comparison of the primary frequency modulation interference signal and the frequency modulation amount, and Figure 7(d), which shows a comparison of the primary frequency modulation interference signal, the frequency modulation command, and the active power, it can be seen that the rate-of-change frequency modulation only operates when the primary frequency modulation rate and the primary frequency modulation amount are in the same direction, and does not operate otherwise.

[0135] Optionally, the sampling frequency of the energy storage controller should be at least twice that of the hardware-in-the-loop simulation platform and the frequency signal source. The frequency slope simulated by the frequency signal source and the hardware-in-the-loop simulation platform is generated by simulating multiple steps. If the sampling frequency of the energy storage controller is less than twice that of the frequency signal source, multiple different results may occur when calculating the slope, which may lead to false positive power generation.

[0136] In one possible implementation, after the waveform recording analyzer determines the test results of the energy storage system inertia test item based on the frequency disturbance signal and the analog signal of the energy storage system, the waveform recording analyzer is further used for:

[0137] According to the expression: Determine the actual inertia time constant of the energy storage system;

[0138] In the formula, T J ΔP represents the actual inertia time constant of the energy storage system. If represents the power change of the energy storage system. N Indicates the rated frequency. P represents the rate of change of frequency. N This indicates the rated active power of the energy storage system.

[0139] In this embodiment, after obtaining the test results, the actual inertia time constant of the tested energy storage system is also calculated for further analysis. Here, the actual inertia time constant differs from the inertia time constant set in the energy storage system: due to aging and other issues, the set inertia time constant may be too large to ensure accurate inertia response, and its value differs from the true inertia time constant; while the actual inertia time constant is the inertia time constant truly exhibited by the energy storage system during its inertia response.

[0140] Optionally, state sequences can be set in both the hardware-in-the-loop simulation platform and the frequency signal source. A state sequence includes multiple states, each corresponding to a frequency change pattern. The aforementioned inertia test items can be repeated using the state sequence. For example, the state sequence includes state 1, state 2, state 3, ..., state n, where the initial frequency disturbance signal is maintained at 50Hz; state 1 is when the frequency disturbance signal decreases from 50Hz to 49Hz at a rate of 0.1Hz / s and remains at 49Hz; state 2 is when the frequency disturbance signal increases from 49Hz to 50Hz at a rate of 0.1Hz / s and remains at 50Hz; state i is when the frequency disturbance signal increases from 50Hz to 50.2Hz at a rate of 0.2Hz / s and remains at 50.2Hz; and state i+1 is when the frequency disturbance signal decreases from 50.2Hz to 50Hz at a rate of 0.2Hz / s and remains at 50Hz. The number of states and the specific states can be set according to the needs of the inertia test items.

[0141] The transition between states can be either automatic entry into the next state after reaching the "maximum duration", or entry into the next state after meeting a trigger condition.

[0142] In addition, when determining the actual inertia time constant of an energy storage system, the final actual inertia time constant can be obtained by calculating the average value of the actual inertia time constant obtained from each test.

[0143] This invention establishes a test system for the inertia of an energy storage system using a hardware-in-the-loop (HIL) platform, an energy storage controller, and a waveform recording and analysis instrument. The HIL generates a simulated signal for the energy storage system and transmits it to the energy storage controller. The energy storage controller adjusts the power based on the inertia time constant and the received simulated signal, determines the power change, and transmits it back to the HIL. The HIL then updates the generated simulated signal based on the power change and transmits it to the waveform recording and analysis instrument. Finally, the waveform recording and analysis instrument uses a frequency disturbance signal and the received simulated signal to determine the test results for the energy storage system's inertia test, thereby obtaining the inertia response of the energy storage system and enabling accurate testing of the energy storage system's inertia. Furthermore, inertia testing via the HIL eliminates the need for direct testing of the energy storage system, avoiding high-voltage wiring by operators on-site and improving the safety and convenience of the test. The system can also include a frequency signal source, which can simulate frequency disturbance signals through either a frequency signal source or a hardware-in-the-loop simulation platform to perform inertia testing. During the test, the inertia time constant is corrected by judging the power change, and the corrected inertia time constant can be directly set to the corresponding energy storage system under test to optimize the inertia of the energy storage system. At the same time, the system can perform inertia test items such as inertia response dead zone test, frequency disturbance test, and primary frequency modulation coordination test. By setting the state sequence, multiple inertia test items can be tested continuously, which can improve the convenience of testing.

[0144] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0145] The following are method embodiments of the present invention. For details not described in detail, please refer to the corresponding system embodiments described above.

[0146] Figure 8 The following is a flowchart illustrating the implementation of a method for testing the inertia of an energy storage system based on a hardware-in-the-loop simulation platform, provided by an embodiment of the present invention. This method is applied to a hardware-in-the-loop simulation platform; for ease of explanation, only the parts relevant to the embodiment of the present invention are shown:

[0147] like Figure 8 As shown, the method for testing the inertia of an energy storage system based on a hardware-in-the-loop simulation platform includes:

[0148] Step S801: The generated analog signal is transmitted to the energy storage controller so that the energy storage controller can determine the power change based on the inertia time constant of the energy storage system and the received analog signal, and transmit it to the hardware-in-the-loop simulation platform.

[0149] Step S802: Update the generated analog signal according to the power change to obtain the analog signal of the simulated energy storage system, and transmit the analog signal of the energy storage system to the waveform recording and analysis instrument so that the waveform recording and analysis instrument can determine the test result of the inertia test item of the energy storage system according to the frequency disturbance signal and the analog signal of the energy storage system; wherein, the frequency disturbance signal is determined according to the inertia test item.

[0150] The specific implementation process and principle of this embodiment can be found in [reference]. Figure 1 The specific description of the illustrated embodiment will not be repeated here.

[0151] This invention generates simulated signals for an energy storage system through a hardware-in-the-loop (HIL) simulation platform and transmits them to an energy storage controller. The controller then adjusts the power based on the inertia time constant and the received simulated signals to determine the power change, which is also transmitted back to the HIL simulation platform. The HIL simulation platform updates the generated simulated signals based on the power change and transmits them to a waveform recording and analysis instrument. This instrument then determines the test results for the energy storage system's inertia test based on the frequency disturbance signal and the received simulated signals, thereby obtaining the inertia response of the energy storage system and enabling accurate testing of the system's inertia. Furthermore, inertia testing via the HIL simulation platform eliminates the need for direct testing of the energy storage system, avoiding high-voltage wiring by operators on-site and improving testing safety and convenience.

[0152] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0153] Those skilled in the art will recognize that the templates, units, and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0154] If a module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory, random access memory, electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0155] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A testing system for the inertia of an energy storage system based on a hardware-in-the-loop simulation platform, characterized in that, This includes a hardware-in-the-loop simulation platform, an energy storage controller, and a waveform recording and analysis instrument; The analog output terminal of the hardware-in-the-loop simulation platform is connected to the input terminal of the energy storage controller, and is used to transmit the generated analog signals to the energy storage controller; wherein, the hardware-in-the-loop simulation platform is used to simulate and generate analog signals of the energy storage system, the analog signals including voltage signals, current signals and power signals of the energy storage system; The output terminal of the energy storage controller is connected to the digital input terminal of the hardware-in-the-loop simulation platform. The energy storage controller is used to determine the power change based on the inertia time constant of the energy storage system and the received analog signal, and transmit it to the hardware-in-the-loop simulation platform. The hardware-in-the-loop simulation platform updates the generated analog signal based on the power change to obtain the analog signal simulating the energy storage system. The analog output terminal of the hardware-in-the-loop simulation platform is also connected to the input terminal of the waveform recording and analysis instrument, for transmitting the analog signal of the energy storage system to the waveform recording and analysis instrument. The waveform recording and analysis instrument determines the test result of the inertia test item of the energy storage system based on the frequency disturbance signal and the analog signal of the energy storage system; wherein, the frequency disturbance signal is determined based on the inertia test item. The energy storage controller, after determining the power change based on the inertia time constant of the energy storage system and the received analog signal, is also used for: Determine whether the power change is less than a preset threshold; If the power change is less than the preset threshold, the inertia time constant is updated, and the power change is re-determined until the re-determined power change is equal to or greater than the preset threshold. After the waveform recording and analysis instrument determines the test results of the inertia test item of the energy storage system based on the frequency disturbance signal and the analog signal of the energy storage system, the waveform recording and analysis instrument is also used to: calculate the actual inertia time constant of the energy storage system.

2. The energy storage system inertia testing system based on a hardware-in-the-loop simulation platform according to claim 1, characterized in that, The hardware-in-the-loop simulation platform is also used to determine the frequency disturbance signal based on the inertia test item; The energy storage controller is used to determine the power change based on the inertia time constant of the energy storage system, the received analog signal, and the frequency disturbance signal.

3. The energy storage system inertia testing system based on a hardware-in-the-loop simulation platform according to claim 1, characterized in that, The test system also includes a frequency signal source; The output terminal of the frequency signal source is connected to the input terminal of the energy storage controller, and is used to determine the frequency disturbance signal according to the inertia test item, and transmit the frequency disturbance signal to the energy storage controller. The energy storage controller determines the power change based on the inertia time constant, the received analog signal and the frequency disturbance signal. The output of the frequency signal source is also connected to the input of the waveform recording and analysis instrument, for sending the frequency disturbance signal to the waveform recording and analysis instrument.

4. The energy storage system inertia testing system based on a hardware-in-the-loop simulation platform according to claim 1, characterized in that, The energy storage controller updates the inertia time constant, including: According to the expression: Update the inertia time constant; In the formula, Indicates the first The updated inertia time constant Indicates the first The updated inertia time constant .

5. The energy storage system inertia testing system based on a hardware-in-the-loop simulation platform according to claim 2 or 3, characterized in that, The inertia testing items include inertia response dead zone test; Determining the frequency disturbance signal based on the inertia test item includes: Calculate the difference between the inertial response dead zone and the control accuracy of the energy storage controller, and the sum of the inertial response dead zone and the control accuracy of the energy storage controller. The frequency signal corresponding to the inertial response dead zone, the frequency signal corresponding to the difference, and the frequency signal corresponding to the sum are used as the frequency disturbance signal.

6. The energy storage system inertia testing system based on a hardware-in-the-loop simulation platform according to claim 2 or 3, characterized in that, The inertia test includes a frequency disturbance test, and the frequency disturbance signal includes a frequency disturbance upper disturbance signal and a frequency disturbance lower disturbance signal; Determining the frequency disturbance signal based on the inertia test item includes: Determine the frequency disturbance change rate corresponding to the frequency disturbance signal in the frequency disturbance test, wherein the frequency disturbance change rate is greater than the inertial response dead zone of the energy storage system; The frequency signal that is increased to a preset first upscratching frequency at the frequency perturbation rate and then decreased to the preset frequency at the frequency perturbation rate after being held at the first upscratching frequency for a first preset time is used as the frequency perturbation upscratching signal. The frequency signal that decreases from the preset frequency to a preset first downscrambling frequency at the frequency perturbation rate, and then increases back to the preset frequency at the frequency perturbation rate after maintaining the first downscrambling frequency for a first preset time, is used as the frequency perturbation downscrambling signal.

7. The energy storage system inertia testing system based on a hardware-in-the-loop simulation platform according to claim 2 or 3, characterized in that, The inertia test includes a primary frequency modulation coordination test, and the frequency disturbance signal includes a primary frequency modulation upscratching signal and a primary frequency modulation downscratching signal. Determining the frequency disturbance signal based on the inertia test item includes: Determine the primary frequency modulation change rate and primary frequency modulation change amount corresponding to the frequency disturbance signal in the primary frequency modulation coordination test. The primary frequency modulation change rate is greater than the inertia response dead zone of the energy storage system, and the primary frequency modulation change amount is greater than the frequency change dead zone of the energy storage system. Based on the first frequency modulation change, determine the second upper scrambling frequency and the second lower scrambling frequency corresponding to the preset frequency; The frequency signal that is raised to the second upscrambling frequency at the first frequency modulation rate and then lowered to the preset frequency at the first frequency modulation rate after maintaining the second upscrambling frequency for a second preset time is used as the first frequency modulation upscrambling signal. The frequency signal that decreases from the preset frequency to the second downscrambling frequency at the first frequency modulation rate, and then increases back to the preset frequency at the first frequency modulation rate after maintaining the second downscrambling frequency for a second preset time, is used as the first frequency modulation downscrambling signal.

8. The energy storage system inertia testing system based on a hardware-in-the-loop simulation platform according to claim 2 or 3, characterized in that, The calculation of the actual inertia time constant of the energy storage system includes: According to the expression: Determine the actual inertia time constant of the energy storage system; In the formula, This represents the actual inertia time constant of the energy storage system. This indicates the power change of the energy storage system. Indicates the rated frequency. Indicates the rate of change of frequency. This indicates the rated active power of the energy storage system.

9. A method for testing the inertia of an energy storage system based on a hardware-in-the-loop simulation platform, characterized in that, The method is applied to a hardware-in-the-loop (HIPL) simulation platform, which is used to simulate and generate analog signals for an energy storage system. The method includes: The generated analog signal is transmitted to the energy storage controller, which determines the power change based on the inertia time constant of the energy storage system and the received analog signal, and then transmits it to the hardware-in-the-loop simulation platform. The analog signal includes the voltage, current, and power signals of the energy storage system. After determining the power change based on the inertia time constant and the received analog signal, the energy storage controller further determines whether the power change is less than a preset threshold. If the power change is less than the preset threshold, the inertia time constant is updated, and the power change is re-determined until the re-determined power change is equal to or greater than the preset threshold. The analog signal generated based on the power change is used to obtain an analog signal simulating the energy storage system. This analog signal is then transmitted to a waveform recording and analysis instrument, which determines the test results of the energy storage system's inertia test based on the frequency disturbance signal and the analog signal. The frequency disturbance signal is determined based on the inertia test. After the waveform recording and analysis instrument determines the test results of the energy storage system's inertia test based on the frequency disturbance signal and the analog signal, it further calculates the actual inertia time constant of the energy storage system.

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