Parameter adjustment method for energy storage system

Abstract

This application provides a parameter adjustment method for an energy storage system. The method includes: acquiring the AC-side voltage and AC-side current of the virtual synchronous machine corresponding to the energy storage system, and calculating the AC-side active power of the virtual synchronous machine based on the AC-side voltage and AC-side current; controlling the active power of the virtual synchronous machine to deduce the current angular rate change and current angular velocity change rate corresponding to the AC-side voltage through the AC-side active power; determining whether the current angular rate change and current angular velocity change rate meet the system steady-state conditions; when the current angular rate change and current angular velocity change rate do not meet the system steady-state conditions, determining the target angular velocity change range corresponding to the current angular rate change and the target angular velocity change rate range corresponding to the current angular velocity change; and determining the correction value of a preset correction parameter based on the adjustment strategy corresponding to the target angular velocity change range and the target angular velocity change rate range.

Description

Technical Field

[0001] This application relates to the field of energy storage system technology, and in particular to a parameter adjustment method for an energy storage system. Background Technology

[0002] Multiple energy storage units are connected in series on each single-phase bridge arm of the energy storage system. Each energy storage unit can perform multi-level output through a bridge circuit, which reduces harmonic content, provides a voltage that is close to the AC waveform, improves voltage quality, and allows electrical energy to flow bidirectionally for charging and discharging.

[0003] In existing technologies, when an energy storage system is connected to the grid, the traditional power control method relies on a phase-locked loop to obtain the phase information of the grid voltage in order to control the AC output of the energy storage system to synchronize with the grid. This method is susceptible to grid fluctuations and cannot provide active support to the grid when there are faults such as short circuits or open circuits. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide at least one parameter adjustment method for an energy storage system. This method determines the active power on the AC side by determining the voltage and current on the AC side of the energy storage system, and determines the current angular rate change and current angular velocity change rate by combining the active power control of the virtual synchronous machine with the AC side active power. The steady-state condition of the energy storage system is judged by the current angular rate change and current angular velocity change rate. When the energy storage system is not in a steady-state state, a strategy for adjusting preset correction parameters is determined by referring to the interval to which the current angular rate change and current angular velocity change rate belong, and the corrected preset correction parameters are obtained to control the energy storage system to a steady-state state. This solves the technical problem in the prior art where fluctuations on the AC side of the energy storage system affect the steady-state state of the energy storage system, achieving the technical effect of providing stability to the energy storage system.

[0005] This application mainly includes the following aspects:

[0006] In a first aspect, embodiments of this application provide a parameter adjustment method for an energy storage system. The parameter adjustment method includes: acquiring the AC-side voltage and AC-side current of a virtual synchronous machine corresponding to the energy storage system, and calculating the AC-side active power of the virtual synchronous machine based on the AC-side voltage and AC-side current; controlling the active power of the virtual synchronous machine, and calculating the current angular rate change and current angular velocity change rate corresponding to the AC-side voltage based on the AC-side active power; determining whether the current angular rate change and current angular velocity change rate meet the system steady-state conditions; and adjusting the current angular rate change... When the change in angular velocity and the current rate of change of angular velocity do not meet the steady-state conditions of the system, the target angular velocity change range corresponding to the change in angular velocity and the target angular velocity change rate range corresponding to the current rate of change of angular velocity are determined. Based on the adjustment strategy corresponding to the target angular velocity change range and the target angular velocity change rate range, the correction value of the preset correction parameter is determined so that the change in angular velocity and the rate of change of angular velocity can be controlled to meet the steady-state conditions of the system through the corrected preset correction parameter. The preset correction parameter is used to indicate the parameters that affect the change in angular velocity and the rate of change of angular velocity by active power control.

[0007] Optionally, the AC side voltage is used to indicate the voltage of the virtual synchronizer in the direct-axis quadrature-axis coordinate system, and the AC side current is used to indicate the current of the virtual synchronizer in the direct-axis quadrature-axis coordinate system. The AC side active power is used to describe the AC side active power of the energy storage system obtained by filtering out high-frequency components in the instantaneous active power and transforming the direct-axis quadrature-axis coordinate system.

[0008] Optionally, the active power control of the virtual synchronous machine is used to indicate that the desired active power on the AC side of the virtual synchronous machine is equal to the active power on the AC side plus the power component related to the moment of inertia generated by the derivative of the angular velocity with respect to time minus the power component affected by the droop coefficient and the damping coefficient. The current angular rate change and the current angular rate change rate corresponding to the AC side voltage are calculated by: introducing the active power on the AC side into the active power control of the virtual synchronous machine to solve for the current angular velocity, and taking the difference between the current angular velocity and the previously calculated angular velocity as the current angular rate change, and taking the ratio of the current angular rate change to its corresponding time difference as the current angular rate change rate.

[0009] Optionally, the energy storage system includes a three-phase bridge arm, and each single-phase bridge arm includes multiple energy storage units. The AC side is used to describe the side where the energy storage system is connected to external devices. The external devices include power supplies that charge each energy storage unit or electrical devices that receive power from each energy storage unit.

[0010] Optionally, before determining the target angular velocity change range corresponding to the current angular velocity change and the target angular velocity change rate range corresponding to the current angular velocity change rate, the parameter adjustment method further includes: obtaining the power and value of each energy storage unit connected to the energy storage system; and determining whether to adjust the droop coefficient according to the comparison result between the power and value and the preset power range of the external device.

[0011] Optionally, the target angular velocity change range includes a preset angular velocity change range or a mutually exclusive angular velocity change range, the target angular velocity change rate range includes a preset angular velocity change rate range or a mutually exclusive angular velocity change rate range, the preset correction parameters include moment of inertia and damping coefficient, and the adjustment strategy includes: when the absolute value of the current angular velocity change belongs to the preset angular velocity change range, the adjustment strategy is to set the moment of inertia to a preset initial moment of inertia and set the damping coefficient to a preset initial damping coefficient; when the absolute value of the current angular velocity change belongs to the mutually exclusive angular velocity change range, the adjustment strategy is determined based on the target angular velocity change rate range.

[0012] Optionally, when the absolute value of the current angular velocity change belongs to the mutually exclusive angular velocity change range and the absolute value of the current angular velocity change rate belongs to the preset angular velocity change rate range, the moment of inertia is corrected by referring to the first moment of inertia correction coefficient and the preset moment of inertia correction amount, and the damping coefficient is corrected by referring to the first damping coefficient correction coefficient and the preset damping coefficient correction amount. When the absolute value of the current angular velocity change belongs to the mutually exclusive angular velocity change range and the absolute value of the current angular velocity change rate belongs to the mutually exclusive angular velocity change rate range, the moment of inertia is corrected by referring to the second moment of inertia correction coefficient and the preset moment of inertia correction amount, and the damping coefficient is corrected by referring to the second damping coefficient correction coefficient and the preset damping coefficient correction amount.

[0013] Optionally, the preset moment of inertia correction and the preset damping coefficient correction can be determined by inputting the current angular rate change and the current angular velocity change rate to the fuzzy controller to obtain the corresponding preset moment of inertia correction and preset damping coefficient correction.

[0014] Optionally, the parameter adjustment method further includes: determining a first closed-loop expression for calculating the rate of change of angular velocity and a second closed-loop expression for calculating the change in angular velocity based on active power control with a closed-loop feedforward element; calculating the adjusted rate of change of angular velocity using the first closed-loop expression and the adjusted change in angular velocity using the second closed-loop expression, according to the correction value of the preset correction parameter and the adjusted droop coefficient, so that the adjusted change in angular velocity and the adjusted rate of change of angular velocity meet the steady-state conditions of the system.

[0015] Optionally, the active power control with the introduction of a closed-loop feedforward is used to describe that the desired active power on the AC side of the virtual synchronous machine is equal to the active power on the AC side plus the power component related to the moment of inertia generated by the derivative of the angular velocity with respect to time plus the active power on the AC side minus the power component affected by the droop coefficient and damping coefficient, and then minus the power component affected by the closed-loop feedforward.

[0016] Optionally, the parameter adjustment method further includes: controlling the corrected moment of inertia to belong to a preset moment of inertia range and the corrected damping coefficient to belong to a preset damping coefficient range.

[0017] Optionally, the preset moment of inertia range and the preset damping coefficient range are determined by the following methods: Based on the small-signal model corresponding to the closed-loop power control of the energy storage system, the expressions for the natural oscillation angular frequency and the damping ratio are determined; based on the link response time expression of the energy storage system and the preset damping ratio range, the range of the natural oscillation angular frequency is calculated, where the link response time expression describes the link response time as equal to the preset coefficient divided by the product of the damping ratio and the natural oscillation angular frequency; based on the natural oscillation angular frequency expression and the range of the natural oscillation angular frequency, the range of the moment of inertia is calculated, where the natural oscillation angular frequency expression describes the influence of the moment of inertia on the natural oscillation angular frequency; based on the damping ratio expression and the range of the moment of inertia, the preset damping coefficient range is calculated, where the natural oscillation angular frequency expression describes the influence of the natural oscillation angular frequency on the damping coefficient.

[0018] This application provides a parameter adjustment method for an energy storage system. The parameter adjustment method includes: acquiring the AC side voltage and AC side current of a virtual synchronous machine corresponding to the energy storage system, and calculating the AC side active power of the virtual synchronous machine based on the AC side voltage and AC side current; controlling the active power of the virtual synchronous machine, and calculating the current angular rate change and current angular velocity change rate corresponding to the AC side voltage based on the AC side active power; determining whether the current angular rate change and current angular velocity change rate meet the system steady-state conditions; and determining whether the current angular rate change... When the current rate of change of angular velocity does not meet the steady-state conditions of the system, the target angular velocity change range corresponding to the current angular velocity change amount and the target angular velocity change rate range corresponding to the current angular velocity change rate are determined; based on the adjustment strategy corresponding to the target angular velocity change range and the target angular velocity change rate range, the correction value of the preset correction parameter is determined, so as to control the angular velocity change amount and angular velocity change rate to meet the steady-state conditions of the system through the corrected preset correction parameter. The preset correction parameter is used to indicate the parameters that affect the angular velocity change amount and angular velocity change rate by active power control. By determining the voltage and current on the AC side of the energy storage system, the active power on the AC side is determined. Then, based on the active power control of the virtual synchronous machine, the current angular rate change and the current angular velocity change rate are determined in conjunction with the AC side active power. The steady-state condition of the energy storage system is judged by the current angular rate change and the current angular velocity change rate. When the energy storage system is not in a steady-state state, a strategy for adjusting preset correction parameters is determined by referring to the interval to which the current angular rate change and the current angular velocity change rate belong. The corrected preset correction parameters are obtained to control the energy storage system to a steady-state state. This solves the technical problem in existing technologies where fluctuations on the AC side of the energy storage system affect the steady-state state of the energy storage system, achieving the technical effect of providing stability to the energy storage system.

[0019] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A flowchart of a parameter adjustment method for an energy storage system provided in an embodiment of this application is shown.

[0022] Figure 2 This paper illustrates a functional block diagram of a parameter adjustment device for an energy storage system provided in an embodiment of this application.

[0023] Figure 3 A schematic diagram of the structure of an electronic device provided in an embodiment of this application is shown. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0025] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0026] In existing technologies, when an energy storage system is connected to the grid, the traditional power control method relies on a phase-locked loop to obtain the phase information of the grid voltage in order to control the power output of the AC side of the energy storage system to synchronize with the grid. This method is susceptible to grid fluctuations and cannot provide active support to the grid when a fault occurs.

[0027] Based on this, this application provides a parameter adjustment method for an energy storage system. The active power on the AC side is determined by measuring the voltage and current on the AC side of the energy storage system. The current angular rate change and current angular velocity change rate are determined by combining the active power control of the virtual synchronous machine with the AC side active power. The steady-state condition of the energy storage system is judged by the current angular rate change and current angular velocity change rate. When the energy storage system is not in a steady-state state, a strategy for adjusting preset correction parameters is determined by referring to the interval to which the current angular rate change and current angular velocity change rate belong. The corrected preset correction parameters are then obtained to control the energy storage system to a steady-state state. This solves the technical problem in the prior art where fluctuations on the AC side of the energy storage system affect the steady-state state of the energy storage system, achieving the technical effect of improving the stability of the energy storage system. Specifically, as follows:

[0028] Please see Figure 1 , Figure 1 This is a flowchart illustrating a parameter adjustment method for an energy storage system provided in an embodiment of this application. Figure 1 As shown in the embodiments of this application, the parameter adjustment method for an energy storage system includes the following steps:

[0029] S101: Obtain the AC side voltage and AC side current of the virtual synchronous machine corresponding to the energy storage system, and calculate the AC side active power of the virtual synchronous machine based on the AC side voltage and AC side current.

[0030] The energy storage system includes a three-phase bridge arm, and each single-phase bridge arm includes multiple energy storage units. The AC side describes the side where the energy storage system is connected to external devices. The external devices include power supplies that charge each energy storage unit or electrical devices that receive power from each energy storage unit.

[0031] The energy storage system also includes an inverter, which is positioned between the three-phase bridge arm and the external equipment. The inverter and the three-phase bridge arm are used to simulate a virtual synchronous machine by referencing a traditional synchronous generator. Furthermore, the AC side voltage of the energy storage system can be understood as the voltage on the side of the inverter connected to the external equipment, or as the AC side voltage of the virtual synchronous machine. Similarly, the AC side current of the energy storage system can be understood as the current on the side of the inverter connected to the external equipment, or as the AC side current of the virtual synchronous machine.

[0032] The AC side voltage indicates the voltage of the virtual synchronizing machine in the direct-axis quadrature-axis coordinate system, and the AC side current indicates the current of the virtual synchronizing machine in the direct-axis quadrature-axis coordinate system. In other words, the AC side voltage and AC side current of the virtual synchronizing machine in the direct-axis quadrature-axis coordinate system are determined by referring to a simulation of a synchronous generator.

[0033] The AC-side active power is used to describe the AC-side active power of the energy storage system obtained by eliminating high-frequency components in the instantaneous active power through a filter and transforming the direct-axis and quadrature-axis coordinate systems.

[0034] The AC side voltage includes virtual direct-axis voltage and virtual quadrature-axis voltage, and the AC side current includes virtual quadrature-axis current and virtual quadrature-axis current.

[0035] Specifically, the active power on the AC side is calculated using the following formula:

[0036]

[0037] In formula (1), P e This refers to the active power on the AC side; For a first-order low-pass filter, τ is the filter's time constant; U d This refers to the virtual direct-axis voltage; U q This refers to the virtual quadrature-axis voltage; I d This refers to the virtual direct-axis current; I q This refers to the virtual cross-axis current.

[0038] In formula (1), the parameters on the right side of the equation are known. Therefore, the active power on the AC side can be calculated by referring to formula (1). Furthermore, by referring to the active power control of the virtual synchronous machine, the change in angular velocity and the rate of change of angular velocity can be calculated.

[0039] S102: Based on the active power control of the virtual synchronous machine, the current angular rate change and the current angular velocity change rate corresponding to the AC side voltage are calculated through the active power on the AC side.

[0040] The active power control of the virtual synchronizer is used to indicate that the desired active power on the AC side of the virtual synchronizer is equal to the active power on the AC side plus the power component related to the moment of inertia generated by the derivative of the angular velocity with respect to time, minus the power component affected by the droop coefficient and the damping coefficient.

[0041] The current angular rate change and the current angular velocity change rate corresponding to the AC side voltage are calculated in the following way: the active power of the AC side is introduced into the active power control of the virtual synchronous machine to solve for the current angular velocity, and the difference between the current angular velocity and the angular velocity calculated in the previous time is taken as the current angular rate change, and the ratio of the current angular rate change to its corresponding time difference is taken as the current angular velocity change rate.

[0042] Specifically, the active power control equations for the virtual synchronous machine include:

[0043]

[0044] In formula (2), P ref This refers to the expected active power on the AC side; P e This refers to the actual calculated active power on the AC side; This refers to the power component related to the moment of inertia due to the rate of change of angular velocity, where J is the moment of inertia and ω is the rotational inertia. ref It is the expected angular velocity. It is the rate of change of angular velocity; (K ω +D×ω ref )×(ω-ω ref K refers to the power component affected by the droop coefficient and damping coefficient. ω ω is the droop coefficient, and ω is the current angular velocity. ref ω is the desired angular velocity, and D is the damping coefficient.

[0045] Furthermore, in the active power control equation, only the current angular velocity ω is an unknown quantity. The current angular velocity ω is calculated based on this, and the difference between the current angular velocity and the previously calculated angular velocity is taken as the change in the current angular velocity. Then, the change in angular velocity is compared with the time difference between the current angular velocity and the previously calculated angular velocity, and the ratio is taken as the rate of change of the current angular velocity.

[0046] S103: Determine whether the current change in angular velocity and the current rate of change in angular velocity meet the steady-state conditions of the system.

[0047] Specifically, determining whether the current angular velocity change and the current angular velocity change rate meet the system steady-state conditions includes: determining whether the current angular velocity change belongs to a preset angular velocity change range, and determining whether the current angular velocity change rate belongs to a preset angular velocity change rate range; if the current angular velocity change belongs to the preset angular velocity change range and the current angular velocity change rate belongs to the preset angular velocity change rate range, then it is determined that the current angular velocity change and the current angular velocity change rate meet the system steady-state conditions.

[0048] Specifically, if the current angular rate change is within the preset angular rate change range and the current angular rate change rate is within the preset angular rate change rate range, then the current angular rate change and the current angular rate change rate are considered to meet the system steady-state conditions, and therefore, there is no need to adjust the preset correction parameters of the energy storage system.

[0049] S104: Determine the target angular velocity change range corresponding to the current angular velocity change and the target angular velocity change rate range corresponding to the current angular velocity change rate.

[0050] Specifically, when the current angular rate change and the current angular velocity change rate do not meet the steady-state conditions of the system, the target angular velocity change range corresponding to the current angular rate change and the target angular velocity change rate range corresponding to the current angular velocity change rate are determined.

[0051] Specifically, before determining the target angular velocity change range corresponding to the current angular velocity change and the target angular velocity change rate range corresponding to the current angular velocity change rate, the parameter adjustment method further includes: obtaining the power and value of each energy storage unit connected to the energy storage system; and determining whether to adjust the droop coefficient according to the comparison result between the power and value and the preset power range of the external device.

[0052] As can be seen from formula (2), the droop coefficient, moment of inertia, and damping coefficient all affect the value of angular velocity, and thus affect the values ​​of angular rate change and angular velocity change rate. The droop coefficient is used to control the output active power of the energy storage system to meet the needs of external equipment. The moment of inertia and damping coefficient are used as preset correction parameters, which are used to indicate the parameters that affect the angular rate change and angular velocity change rate by controlling the active power.

[0053] Furthermore, increasing the damping coefficient can effectively suppress active power oscillations and reduce power overshoot. On the other hand, since the damping coefficient and droop coefficient are coupled, increasing the damping coefficient will effectively increase the droop coefficient, thus increasing the steady-state deviation of the output active power. Therefore, in order to reduce the influence of the droop coefficient on the values ​​of the moment of inertia and damping coefficient, and to avoid coupling between parameters, the droop coefficient and the preset correction parameter are adjusted separately.

[0054] The preset power range is used to indicate the power requirements of external devices. In other words, before adjusting the preset correction parameters, the power and value of each energy storage unit in the energy storage system can be calculated first. This can also be understood as calculating the maximum power that all energy storage units in the energy storage system can provide. If the power and value meet the preset power range, it is considered that the power requirements of the external devices are met, and no adjustment of the droop coefficient is needed. If the power and value do not meet the preset power range, it is considered that the power requirements of the external devices are not met, and the droop coefficient needs to be adjusted.

[0055] Specifically, when the sum of power values ​​is less than the lower limit of the preset power range, the droop coefficient is increased; when the sum of power values ​​is greater than the upper limit of the preset power range, the droop coefficient is decreased; and when the sum of power values ​​is greater than or equal to the lower limit of the preset power range and less than or equal to the upper limit of the preset power range, the droop coefficient is not adjusted. For example, each adjustment of the droop coefficient can be made gradually according to a preset adjustment amount to avoid accelerating angular velocity changes and affecting frequency control, thereby preventing frequency oscillations that could affect the stability of the energy storage system.

[0056] Specifically, the target angular velocity change range corresponding to the current angular velocity change refers to the target angular velocity change range to which the absolute value of the current angular velocity change belongs, and the target angular velocity change rate range corresponding to the current angular velocity change rate refers to the target angular velocity change rate range to which the absolute value of the current angular velocity change rate belongs.

[0057] S105: Based on the adjustment strategy corresponding to the target angular velocity change range and the target angular velocity change rate range, determine the correction value of the preset correction parameter so as to control the angular velocity change and angular velocity change rate to meet the steady-state conditions of the system through the corrected preset correction parameter.

[0058] Specifically, the target angular velocity change range includes a preset angular velocity change range or a mutually exclusive angular velocity change range, the target angular velocity change rate range includes a preset angular velocity change rate range or a mutually exclusive angular velocity change rate range, the preset correction parameters include moment of inertia and damping coefficient, and the adjustment strategy includes: when the absolute value of the current angular velocity change belongs to the preset angular velocity change range, setting the moment of inertia to a preset initial moment of inertia and setting the damping coefficient to a preset initial damping coefficient; when the absolute value of the current angular velocity change belongs to the mutually exclusive angular velocity change range, determining the adjustment strategy based on the target angular velocity change rate range.

[0059] In other words, the preset angular velocity change range and the mutually exclusive angular velocity change range are mutually exclusive, that is, the range that does not belong to the preset angular velocity change range is taken as the mutually exclusive angular velocity change range. Similarly, the preset angular velocity change rate range and the mutually exclusive angular velocity change rate range are mutually exclusive, that is, the range that does not belong to the preset angular velocity change rate range is taken as the mutually exclusive angular velocity change rate range.

[0060] In other words, when the absolute value of the current change in angular velocity falls within a preset range of angular velocity changes, the moment of inertia is set to a preset initial moment of inertia, and the damping coefficient is set to a preset initial damping coefficient; when the absolute value of the current change in angular velocity does not fall within the preset range of angular velocity changes but the absolute value of the current rate of change in angular velocity falls within the preset range of angular velocity change rates, the moment of inertia is corrected by referring to a first moment of inertia correction coefficient and a preset moment of inertia correction amount, and the damping coefficient is corrected by referring to a first damping coefficient correction coefficient and a preset damping coefficient correction amount; when the absolute value of the current change in angular velocity does not fall within the preset range of angular velocity changes and the absolute value of the current rate of change in angular velocity does not fall within the preset range of angular velocity change rates, the moment of inertia is corrected by referring to a second moment of inertia correction coefficient and a preset moment of inertia correction amount, and the damping coefficient is corrected by referring to a second damping coefficient correction coefficient and a preset damping coefficient correction amount.

[0061] The process of correcting the moment of inertia by referring to the first moment of inertia correction coefficient and the preset moment of inertia correction amount, and correcting the damping coefficient by referring to the first damping coefficient correction coefficient and the preset damping coefficient correction amount, includes: adding the product of the first moment of inertia correction coefficient and the preset moment of inertia correction amount to the preset initial moment of inertia as the corrected moment of inertia, and adding the product of the first damping coefficient correction coefficient and the preset damping coefficient correction amount to the preset initial damping coefficient as the corrected damping coefficient.

[0062] The process of correcting the moment of inertia by referring to the second moment of inertia correction coefficient and the preset moment of inertia correction amount, and correcting the damping coefficient by referring to the second damping coefficient correction coefficient and the preset damping coefficient correction amount, includes: adding the product of the second moment of inertia correction coefficient and the preset moment of inertia correction amount to the preset initial moment of inertia as the corrected moment of inertia, and adding the product of the second damping coefficient correction coefficient and the preset damping coefficient correction amount to the preset initial damping coefficient as the corrected damping coefficient.

[0063] For example, a preset range of angular velocity change is set to be less than or equal to a threshold value of angular velocity change, and a preset range of angular velocity rate of change is set to be less than or equal to a threshold value of angular velocity rate of change. Furthermore, when the absolute value of the current change in angular velocity is less than or equal to the threshold value of the change in angular velocity, the moment of inertia and the damping coefficient are controlled to be their respective initial values; when the absolute value of the current change in angular velocity is greater than the threshold value of the change in angular velocity and the absolute value of the current rate of change in angular velocity is less than or equal to the threshold value of the rate of change in angular velocity, the product of the first moment of inertia correction coefficient and the preset moment of inertia correction coefficient, plus the preset initial moment of inertia, is used as the corrected moment of inertia, and the product of the first damping coefficient correction coefficient and the preset damping coefficient correction coefficient, plus the preset initial damping coefficient, is used to obtain the corrected damping coefficient; when the absolute value of the current change in angular velocity is greater than the threshold value of the change in angular velocity and the absolute value of the current rate of change in angular velocity is greater than the threshold value of the rate of change in angular velocity, the product of the second moment of inertia correction coefficient and the preset moment of inertia correction coefficient, plus the preset initial moment of inertia, is used to obtain the corrected moment of inertia, and the product of the second damping coefficient correction coefficient and the preset damping coefficient correction coefficient, plus the preset initial damping coefficient, is used to obtain the corrected damping coefficient.

[0064] Among them, the first and second rotational inertia correction coefficients are factors affecting the rotational inertia, and the first and second damping coefficient correction coefficients are factors affecting the damping coefficient. Furthermore, the first, second, first, and second rotational inertia correction coefficients, as well as the first and second damping coefficient correction coefficients, are all affected by the absolute value of the current rate of change of angular velocity. That is, the aforementioned multiple correction coefficients reflect that the corrected damping coefficient and rotational inertia are adjusted according to the relationship between the absolute value of the current rate of change of angular velocity and the threshold value of the rate of change of angular velocity. This is so that when the change in angular velocity and the rate of change of angular velocity are too large, the corresponding coefficients can be used to correct the damping coefficient and rotational inertia, thereby reducing the subsequent change in angular velocity and the rate of change of angular velocity and further stabilizing the system's operating state.

[0065] Since the increase in moment of inertia and damping coefficient leads to the decrease in angular velocity change and rate of change, when the angular velocity change and rate of change are large, it is necessary to increase the moment of inertia and damping coefficient. That is, the second moment of inertia correction coefficient is greater than the first moment of inertia correction coefficient, and the second damping coefficient correction coefficient is greater than the first damping coefficient correction coefficient.

[0066] For example, both the threshold for change in angular velocity and the threshold for the rate of change in angular velocity are greater than zero.

[0067] Specifically, the preset moment of inertia correction and preset damping coefficient correction are determined as follows: the current angular rate change and the current angular velocity change rate are input to the fuzzy controller to obtain the corresponding preset moment of inertia correction and preset damping coefficient correction.

[0068] For example, the current change in angular velocity and the current rate of change in angular velocity are input into the Mamdani fuzzy system (a linguistic fuzzy system) for fuzzification. Specifically, multiple fuzzy sets corresponding to the current change in angular velocity and their respective membership functions are pre-defined, as are multiple fuzzy sets corresponding to the current rate of change in angular velocity and their respective membership functions. Then, the current change in angular velocity and the current rate of change in angular velocity are respectively processed using scaling factors and quantization factors to obtain their corresponding fuzzified values, ensuring that the fuzzified values ​​for both fall within their respective universes of discourse, and the membership degrees of the fuzzified values ​​are determined based on their respective membership functions. Finally, based on the fuzzified values ​​and membership degrees corresponding to the current change in angular velocity and the current rate of change in angular velocity, defuzzification is performed using centriod (area centroid method) to obtain preset moment of inertia correction and preset damping coefficient correction.

[0069] The parameter adjustment method further includes: determining a first closed-loop expression for calculating the rate of change of angular velocity and a second closed-loop expression for calculating the change in angular velocity based on active power control with a closed-loop feedforward element; calculating the adjusted rate of change of angular velocity using the first closed-loop expression and the adjusted change in angular velocity using the second closed-loop expression, according to the correction value of the preset correction parameter and the adjusted droop coefficient, so that the adjusted change in angular velocity and the adjusted rate of change of angular velocity meet the steady-state conditions of the system.

[0070] The active power control with the introduction of a closed-loop feedforward is used to describe that the desired active power on the AC side of the virtual synchronous machine is equal to the active power on the AC side plus the power component related to the moment of inertia generated by the derivative of angular velocity with respect to time, plus the active power on the AC side minus the power component affected by the droop coefficient and damping coefficient, and then minus the power component affected by the closed-loop feedforward.

[0071] In other words, a feedforward element is introduced into the active power control of the virtual synchronous machine. In steady state, the derivative element is zero, thus having no impact on steady-state characteristics. Since the derivative element may introduce high-frequency noise interference, a low-pass filter is used for filtering. To avoid introducing excessive control lag into the system, a smaller time constant is selected.

[0072] For example, the active power control equations that incorporate a closed-loop feedforward element include:

[0073]

[0074] In formula (3), P ref This refers to the expected active power on the AC side; This refers to the power component related to the moment of inertia due to the rate of change of angular velocity, where J is the moment of inertia and ω is the rotational inertia. ref It is the expected angular velocity. It is the rate of change of angular velocity; P e This refers to the active power on the AC side; P n This refers to the power component introduced by the closed-loop feedforward stage. τ e Let k be the time constant of the first-order low-pass filter. d These are the differential coefficients; (K) ω +D×ω ref )×(ω-ω ref K refers to the power component affected by the droop coefficient and damping coefficient. ω ω is the droop coefficient, and ω is the angular velocity. ref ω is the desired angular velocity, and D is the damping coefficient.

[0075] Furthermore, ω in formula (3)ref This can be understood as the angular velocity calculated previously. Therefore, the first closed-loop expression for calculating the rate of change of angular velocity is as follows: The second closed-loop expression for calculating the change in angular velocity is as follows: Then, by substituting the modified droop coefficient, damping coefficient, and moment of inertia into the first closed-loop expression and the second closed-loop expression, the adjusted rate of change of angular velocity and the amount of change of angular velocity are calculated so that the adjusted rate of change of angular velocity belongs to the preset range of the rate of change of angular velocity, and the adjusted amount of change of angular velocity belongs to the preset range of the amount of change of angular velocity.

[0076] The parameter adjustment method further includes: controlling the corrected moment of inertia to belong to a preset moment of inertia range and the corrected damping coefficient to belong to a preset damping coefficient range.

[0077] The preset rotational inertia range and the preset damping coefficient range are determined as follows: Based on the small-signal model corresponding to the closed-loop power control of the energy storage system, the expressions for the natural oscillation angular frequency and the damping ratio are determined; based on the link response time expression of the energy storage system and the preset damping ratio range, the range of natural oscillation angular frequency values ​​is calculated, where the link response time expression describes that the link response time is equal to the preset coefficient divided by the product of the damping ratio and the natural oscillation angular frequency; based on the natural oscillation angular frequency expression and the range of natural oscillation angular frequency values, the range of rotational inertia values ​​is calculated, where the natural oscillation angular frequency expression describes the influence of rotational inertia on the natural oscillation angular frequency; based on the damping ratio expression and the range of rotational inertia values, the preset damping coefficient range is calculated, where the natural oscillation angular frequency expression describes the influence of the natural oscillation angular frequency on the damping coefficient.

[0078] Specifically, based on the active power control equation with a closed-loop feedforward element, a small-signal model simulation of the virtual synchronous machine in the s-domain is performed to obtain the transfer function under the small-signal model. After performing order reduction analysis on the transfer function, the expressions for the natural oscillation angular frequency and the damping ratio are obtained.

[0079] Among them, the s-domain controlled small-signal models include:

[0080]

[0081] In formula (4), G1(s) refers to the transfer function affecting the output active power of the virtual synchronous machine when the active power changes without angular frequency disturbance, and G2(s) refers to the transfer function affecting the output active power of the virtual synchronous machine when the active power changes without angular frequency disturbance; ΔP ref This refers to the expected change in active power; ΔP eThis refers to the change in active power on the AC side; K refers to the synchronization coefficient. U g Here, E is the grid voltage amplitude, E is the inverter output voltage amplitude, X is the line impedance, J is the moment of inertia, and ω is the line impedance. ref It is the desired angular velocity, τ e Let k be the time constant of the first-order low-pass filter. d K is the differential coefficient. ω is the sag coefficient, and D is the damping coefficient.

[0082] Furthermore, by performing a reduced-order analysis on the transfer function under closed-loop conditions, we obtain:

[0083]

[0084] Formula (5) is obtained by reducing the order of formula (4).

[0085] Specifically, the process response time expression includes:

[0086]

[0087] In formula (6), t sp This refers to the response time of the process, ξ n This refers to the damping ratio, ω n This refers to the natural oscillation angular frequency, with 4.4 being a preset coefficient.

[0088] In other words, according to formula (6), we can obtain The preset damping ratio range is (0.707, 1), and the response time t of the element is... sp The value of is fixed, and thus, the range of natural oscillation angular frequency can be calculated.

[0089] Specifically, the expressions for the natural oscillation angular frequency include:

[0090]

[0091] In formula (7), K refers to the synchronization coefficient. U g Here, E is the grid voltage amplitude, X is the inverter output voltage amplitude, J is the line impedance, and ω is the moment of inertia. ref It is the desired angular velocity, ω n It is the natural oscillation angular frequency.

[0092] Furthermore, the formula for calculating the moment of inertia is derived from the expression for the natural oscillation angular frequency. Furthermore, the range of rotational inertia values ​​is calculated based on the range of natural oscillation angular frequencies.

[0093] Specifically, the damping ratio expression includes:

[0094]

[0095] In formula (8), ξ n This refers to the damping ratio. U g Here, E is the grid voltage amplitude, X is the inverter output voltage amplitude, J is the line impedance, and ω is the moment of inertia. ref It is the desired angular velocity, k d K is the differential coefficient. ω It is the droop coefficient, τ e Let be the time constant of the first-order low-pass filter, and D be the damping coefficient.

[0096] Then, the range of damping coefficient values ​​is calculated according to the damping ratio expression, the range of moment of inertia values, and the preset range of damping ratio values.

[0097] Furthermore, after adjusting the droop coefficient, damping coefficient, and moment of inertia, it is necessary to determine the desired AC voltage of each single-phase bridge arm. Then, using a closest-to-the-level approximation method, the bridge circuit corresponding to the energy storage unit under each single-phase bridge arm is controlled to ensure that the AC side voltage of the single-phase bridge arm approaches the desired AC voltage, and consequently, the AC side voltage of the energy storage system approaches the desired AC side voltage. Moreover, the error band between the active power on the AC side of the energy storage system and the desired active power on the AC side is maintained within 0.02.

[0098] Specifically, the desired arm voltage of each single-phase arm is determined in the following way: the AC reactive power of the virtual synchronous machine is calculated based on the AC side voltage and the AC side current; the desired arm voltage of each single-phase arm is calculated based on the excitation control of the virtual synchronous machine and the AC side reactive power.

[0099] The reactive power on the AC side is calculated using the following formula:

[0100]

[0101] In formula (9), Q e This refers to reactive power on the AC side; For a first-order low-pass filter, τ is the filter's time constant; Q d This refers to the virtual direct-axis voltage; Q q This refers to the virtual quadrature-axis voltage; I d This refers to the virtual direct-axis current; I q This refers to the virtual cross-axis current.

[0102] Specifically, the reactive power control equations for the virtual synchronous machine include:

[0103]

[0104] In formula (10), Q ref This refers to the expected reactive power on the AC side; Q e This refers to the reactive power on the AC side; K q This refers to the reactive power integral coefficient; This refers to the rate of change of the inverter output voltage amplitude in the outer loop; K v This refers to the voltage droop coefficient; U ref This refers to the AC side reference voltage; U refers to the AC side voltage amplitude.

[0105] Furthermore, since the parameter on the right side of the equal sign in formula (9) is known, the reactive power on the AC side can be calculated by referring to formula (9). Furthermore, the inverter output voltage amplitude E can be calculated by referring to formula (10). The desired AC voltage value can then be calculated based on the inverter output voltage amplitude E. Therefore, based on the star or delta connection method between the three-phase bridge arms connected to the inverter, the desired bridge arm voltage of each single-phase bridge arm is calculated, so as to control the AC side voltage of each single-phase bridge arm to approach the desired bridge arm voltage according to the nearest level approximation, so as to control the energy storage system to charge and discharge externally.

[0106] Based on the same application concept, this application also provides a parameter adjustment device for an energy storage system corresponding to the parameter adjustment method of the energy storage system provided in the above embodiments. Since the principle of the device in this application is similar to the parameter adjustment method of the energy storage system in the above embodiments of this application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be described again.

[0107] like Figure 2 As shown, Figure 2This application provides a functional block diagram of a parameter adjustment device for an energy storage system. The parameter adjustment device 10 includes: an acquisition module 101, which acquires the AC side voltage and AC side current of the virtual synchronous machine corresponding to the energy storage system, and calculates the AC side active power of the virtual synchronous machine based on the AC side voltage and AC side current; a calculation module 102, which, based on the active power control of the virtual synchronous machine, calculates the current angular rate change and current angular velocity change rate corresponding to the AC side voltage through the AC side active power; a first determination module 103, which determines whether the current angular rate change and current angular velocity change rate meet the system steady-state conditions; and a second determination module 104, which, based on the current angular rate change and current angular velocity change rate, calculates whether the current angular rate change and current angular velocity change rate meet the system steady-state conditions. When the rate change and the current angular velocity change rate do not meet the steady-state conditions of the system, the target angular velocity change range corresponding to the current angular velocity change and the target angular velocity change rate range corresponding to the current angular velocity change are determined; the correction module 105 determines the correction value of the preset correction parameter based on the adjustment strategy corresponding to the target angular velocity change range and the target angular velocity change rate range, so as to control the angular velocity change and the angular velocity change rate to meet the steady-state conditions of the system through the corrected preset correction parameter. The preset correction parameter is used to indicate the parameters that affect the angular velocity change and the angular velocity change rate by active power control.

[0108] Based on the same application concept, see [link / reference] Figure 3 The diagram shown is a structural schematic of an electronic device provided in an embodiment of this application. The electronic device 20 includes a processor 201, a memory 202, and a bus 203. The memory 202 stores machine-readable instructions that can be executed by the processor 201. When the electronic device 20 is running, the processor 201 and the memory 202 communicate through the bus 203. When the machine-readable instructions are executed by the processor 201, they perform the steps of the parameter adjustment method of the energy storage system as described in any of the above embodiments.

[0109] Specifically, when the machine-readable instructions are executed by the processor 201, the following processing can be performed: obtaining the AC-side voltage and AC-side current of the virtual synchronous machine corresponding to the energy storage system, and calculating the AC-side active power of the virtual synchronous machine based on the AC-side voltage and AC-side current; based on the active power control of the virtual synchronous machine, calculating the current angular rate change and current angular velocity change rate corresponding to the AC-side voltage through the AC-side active power; determining whether the current angular rate change and current angular velocity change rate meet the system steady-state conditions; and determining whether the current angular rate change... When the current rate of change of angular velocity does not meet the steady-state conditions of the system, the target angular velocity change range corresponding to the current angular velocity change amount and the target angular velocity change rate range corresponding to the current angular velocity change rate are determined; based on the adjustment strategy corresponding to the target angular velocity change range and the target angular velocity change rate range, the correction value of the preset correction parameter is determined, so as to control the angular velocity change amount and angular velocity change rate to meet the steady-state conditions of the system through the corrected preset correction parameter. The preset correction parameter is used to indicate the parameters that affect the angular velocity change amount and angular velocity change rate by active power control.

[0110] Based on the same concept, this application also provides a computer-readable storage medium storing a computer program, which, when run by a processor, executes the steps of the parameter adjustment method for the energy storage system provided in the above embodiments.

[0111] Specifically, the storage medium can be a general-purpose storage medium, such as a portable disk or hard disk. When the computer program on the storage medium is run, it can execute the parameter adjustment method of the energy storage system described above. By determining the voltage and current on the AC side of the energy storage system, the active power on the AC side is determined. The current angular rate change and the current angular velocity change rate are determined in combination with the active power control of the virtual synchronous machine. The steady-state condition of the energy storage system is judged by the current angular rate change and the current angular velocity change rate. When the energy storage system is not in a steady-state state, the strategy of adjusting the preset correction parameters is determined by referring to the interval to which the current angular rate change and the current angular velocity change rate belong, and the corrected preset correction parameters are obtained to control the energy storage system to a steady-state state. This solves the technical problem in the prior art that fluctuations on the AC side of the energy storage system will affect the steady-state state of the energy storage system, and achieves the technical effect of providing stability to the energy storage system.

[0112] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems and devices described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division; in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection may be through some communication interfaces; the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms.

[0113] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0114] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0115] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0116] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method of parameter adjustment of an energy storage system, characterized by, The parameter adjustment method includes: Obtain the AC side voltage and AC side current of the virtual synchronous machine corresponding to the energy storage system, and calculate the AC side active power of the virtual synchronous machine based on the AC side voltage and AC side current; Based on the active power control of the virtual synchronous machine, the current angular rate change and the current angular velocity change rate corresponding to the AC side voltage are calculated through the active power on the AC side. Determine whether the current change in angular velocity and the current rate of change in angular velocity meet the system steady-state conditions; When the current angular velocity change and the current angular velocity change rate do not meet the system steady-state conditions, determine the target angular velocity change range corresponding to the current angular velocity change and the target angular velocity change rate range corresponding to the current angular velocity change rate; Based on the adjustment strategy corresponding to the target angular velocity change range and the target angular velocity change rate range, the correction value of the preset correction parameter is determined so that the angular velocity change and angular velocity change rate are controlled to meet the steady-state conditions of the system through the corrected preset correction parameter. The preset correction parameter is used to indicate the parameters that affect the angular velocity change and angular velocity change rate by active power control.

2. The parameter adjustment method according to claim 1, characterized by, The AC side voltage is used to indicate the voltage of the virtual synchronizer in the direct-axis quadrature-axis coordinate system, and the AC side current is used to indicate the current of the virtual synchronizer in the direct-axis quadrature-axis coordinate system. The AC-side active power is used to describe the AC-side active power of the energy storage system obtained by eliminating high-frequency components in the instantaneous active power through a filter and transforming the direct-axis and quadrature-axis coordinate systems.

3. The method of claim 1, wherein, The active power control of the virtual synchronizer is used to indicate that the desired active power on the AC side of the virtual synchronizer is equal to the active power on the AC side plus the power component related to the moment of inertia generated by the derivative of angular velocity with respect to time, minus the power component affected by the droop coefficient and damping coefficient. The current angular rate change and the current angular velocity change rate corresponding to the AC side voltage are calculated using the following methods: The active power control of the virtual synchronous machine is introduced to calculate the current angular velocity by using the active power on the AC side. The difference between the current angular velocity and the previously calculated angular velocity is taken as the change in the current angular rate, and the ratio of the change in the current angular rate to the corresponding time difference is taken as the rate of change of the current angular velocity.

4. The method of claim 1, wherein, The energy storage system includes three-phase bridge arms, and each single-phase bridge arm includes multiple energy storage units. The AC side describes the side where the energy storage system is connected to external devices, which include power sources that charge each energy storage unit or electrical devices that receive power from each energy storage unit.

5. The method of claim 4, wherein, Before determining the target angular velocity change range corresponding to the current angular velocity change and the target angular velocity change rate range corresponding to the current angular velocity change rate, the parameter adjustment method further includes: Obtain the power and values ​​of each energy storage unit connected to the energy storage system; Based on the comparison between the power and value and the preset power range of the external device, determine whether to adjust the droop coefficient.

6. The parameter adjustment method according to claim 1 or 5, characterized by, The target angular velocity change range includes a preset angular velocity change range or mutually exclusive angular velocity change ranges; the target angular velocity change rate range includes a preset angular velocity change rate range or mutually exclusive angular velocity change rate ranges; and the preset correction parameters include moment of inertia and damping coefficient. The adjustment strategy includes: When the absolute value of the current angular velocity change falls within the preset angular velocity change range, the adjustment strategy is to set the moment of inertia to a preset initial moment of inertia and the damping coefficient to a preset initial damping coefficient. When the absolute value of the current angular velocity change falls within the mutually exclusive angular velocity change range, an adjustment strategy is determined based on the target angular velocity change range.

7. The method of claim 6, wherein, When the absolute value of the current angular velocity change falls within the mutually exclusive angular velocity change interval and the absolute value of the current angular velocity change rate falls within the preset angular velocity change rate interval, the moment of inertia is corrected by referring to the first moment of inertia correction coefficient and the preset moment of inertia correction amount, and the damping coefficient is corrected by referring to the first damping coefficient correction coefficient and the preset damping coefficient correction amount. When the absolute value of the current angular velocity change belongs to the interval of mutually exclusive angular velocity changes and the absolute value of the current angular velocity change rate belongs to the interval of mutually exclusive angular velocity change rates, the rotational inertia is corrected by referring to the second rotational inertia correction coefficient and the preset rotational inertia correction amount, and the damping coefficient is corrected by referring to the second damping coefficient correction coefficient and the preset damping coefficient correction amount.

8. The method of claim 7, wherein, The preset moment of inertia correction and preset damping coefficient correction are determined in the following ways: The current angular rate change and the current angular velocity change rate are input to the fuzzy controller to obtain the corresponding preset moment of inertia correction and preset damping coefficient correction.

9. The method of claim 6, wherein, The parameter adjustment method further includes: Based on the active power control with the introduction of a closed-loop feedforward link, the first closed-loop expression for calculating the rate of change of angular velocity and the second closed-loop expression for calculating the change in angular velocity are determined. Based on the correction values ​​of the preset correction parameters and the adjusted droop coefficient, the adjusted rate of change of angular velocity is calculated through the first closed-loop expression, and the adjusted change of angular velocity is calculated through the second closed-loop expression, so that the adjusted change of angular velocity and the adjusted rate of change of angular velocity meet the steady-state conditions of the system.

10. The method of claim 9, wherein, The active power control with the introduction of a closed-loop feedforward is used to describe that the desired active power on the AC side of the virtual synchronous machine is equal to the active power on the AC side plus the power component related to the moment of inertia generated by the derivative of angular velocity with respect to time, plus the active power on the AC side minus the power component affected by the droop coefficient and damping coefficient, and then minus the power component affected by the closed-loop feedforward.

11. The method of claim 7, wherein, The parameter adjustment method further includes: The corrected moment of inertia is controlled to fall within the preset moment of inertia range, and the corrected damping coefficient is controlled to fall within the preset damping coefficient range.

12. The method of claim 11, wherein, The preset moment of inertia range and the preset damping coefficient range are determined in the following ways: Based on the small-signal model corresponding to the closed-loop power control of the energy storage system, the expressions for the natural oscillation angular frequency and the damping ratio are determined. Based on the link response time expression of the energy storage system and the preset damping ratio range, the range of natural oscillation angular frequency is calculated. The link response time expression describes that the link response time is equal to the preset coefficient divided by the product of the damping ratio and the natural oscillation angular frequency. Based on the expression for the natural oscillation angular frequency and the range of values ​​for the natural oscillation angular frequency, the range of values ​​for the moment of inertia is calculated. The expression for the natural oscillation angular frequency describes how the moment of inertia affects the value of the natural oscillation angular frequency. Based on the damping ratio expression and the range of the moment of inertia, a preset damping coefficient range is calculated. The natural oscillation angular frequency expression describes the influence of the natural oscillation angular frequency on the value of the damping coefficient.

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