Multi-scene cooperative control method, device and equipment for network construction type energy storage converter and storage medium

Abstract

The invention discloses a multi-scene cooperative control method, device and equipment for a network construction type energy storage converter, and a storage medium, relates to the technical field of converter control, and discloses the multi-scene cooperative control method for the network construction type energy storage converter, and the method comprises the steps: obtaining the state data of a power grid, determining grid-connected point power, power grid frequency, power grid voltage and power grid harmonic frequency spectrum according to the power grid state data; establishing a multi-objective optimization function, an energy storage system charge state constraint and a converter output current constraint based on the grid-connected point power, the power grid frequency, the power grid voltage and the power grid harmonic spectrum; and performing multi-objective optimization solution based on the multi-objective optimization function, the charge state constraint of the energy storage system and the output current constraint of the converter to obtain a fundamental current reference value and a harmonic current limit value so as to control the output current of the grid-forming type energy storage converter. According to the scheme of the invention, the capacity conflict between network construction type control and harmonic suppression can be solved.

Description

Technical Field

[0001] The present application relates to the field of converter control technology, and in particular to a multi-scenario collaborative control method, apparatus, device and storage medium for a grid-type energy storage converter. Background Art

[0002] As a key flexible regulation unit in power systems, energy storage converters are crucial for achieving flexible conversion and efficient management of electrical energy, ensuring stable grid operation and reliable power quality. With the increasing penetration of renewable energy and the prevalence of weak grid scenarios, the control mode of energy storage converters is shifting from a traditional passive grid-following model to an active grid-forming model. To fully utilize the capacity of energy storage devices and assist with grid harmonic control, converters must reserve some capacity to operate harmonic suppression modules. This creates a competition between the power margin required for grid-forming control and the harmonic control capacity.

[0003] Currently, most existing technologies use fixed weight allocation or module priority removal strategies to address the competitive relationship between the power margin required for grid-based control and harmonic control capacity, thereby achieving a balance between multiple functions such as power support and harmonic suppression. However, harmonic limit settings based on static thresholds are difficult to adapt to dynamic changes in grid impedance and can easily lead to insufficient harmonic compensation or grid-based control failure in scenarios with fluctuating short-circuit ratios. Therefore, how to resolve the capacity conflict between grid-based control and harmonic control to achieve multi-scenario coordinated control of grid-based energy storage converters has become an unresolved issue.

[0004] The above content is only used to assist in understanding the technical solution of this application and does not constitute an admission that the above content is prior art. Summary of the Invention

[0005] The main purpose of this application is to provide a multi-scenario collaborative control method, device, equipment and storage medium for a grid-type energy storage converter, aiming to solve the technical problem of how to resolve the capacity conflict between grid-type control and harmonic control to perform multi-scenario collaborative control of a grid-type energy storage converter.

[0006] To achieve the above objectives, the present application proposes a multi-scenario collaborative control method for a grid-type energy storage converter, the method comprising:

[0007] Obtaining grid status data, and determining grid connection point power, grid frequency, grid voltage, and grid harmonic spectrum based on the grid status data;

[0008] Establishing a multi-objective optimization function, energy storage system state of charge constraints, and converter output current constraints based on the grid connection point power, the grid frequency, the grid voltage, and the grid harmonic spectrum;

[0009] Perform multi-objective optimization based on the multi-objective optimization function, the energy storage system state of charge constraint, and the converter output current constraint to obtain a fundamental current reference value and a harmonic current limit value;

[0010] The output current of the grid-type energy storage converter is controlled based on the grid-type fundamental current reference value and the grid-type harmonic current limit value.

[0011] In one embodiment, the step of establishing a multi-objective optimization function, energy storage system state of charge constraints, and converter output current constraints based on the grid connection point power, the grid frequency, the grid voltage, and the grid harmonic spectrum includes:

[0012] Determining a grid connection point active power historical data sequence, a frequency deviation, a voltage deviation, an output current fundamental component amplitude, and an output current harmonic component amplitude based on the grid connection point power, grid frequency, grid voltage, and grid harmonic spectrum;

[0013] Predicting grid power fluctuations based on the historical data sequence of active power at the grid connection point;

[0014] Constructing a multi-objective optimization function based on the grid power fluctuation, the frequency deviation, the voltage deviation, and the amplitude of the output current fundamental component;

[0015] Establishing the energy storage system's state of charge constraints based on the energy storage system's current state of charge, energy storage output power, rated capacity, and control period;

[0016] A converter output current constraint is established according to the amplitude of the output current fundamental component and the amplitude of the output current harmonic component.

[0017] In one embodiment, before the step of controlling the output current of the grid-type energy storage converter based on the grid-type fundamental current reference value and the grid-type harmonic current limit value, the step further includes:

[0018] Based on the grid status data, the transient voltage mutation sign parameter, transient frequency disturbance sign parameter, grid strength assessment parameter, frequency deviation duration parameter, and energy storage system charge state parameter are determined to obtain the grid-type control mode switching information;

[0019] When the network-type control mode switching information meets the preset switching condition, determining the target network-type control mode to be the virtual synchronous control mode or the droop control mode;

[0020] Based on the target grid-type control mode, inverter control reference parameters are determined according to inverter grid-connected point output voltage measurement parameters and inverter grid-connected point output current measurement parameters.

[0021] In one embodiment, before the step of determining the inverter control reference parameters according to the inverter grid-connected point output voltage measurement parameters and the inverter grid-connected point output current measurement parameters based on the target grid-connected control mode, the method includes:

[0022] When the target network control mode is the virtual synchronous control mode, initializing the current inner loop of the virtual synchronous control according to the output result of the droop control at the switching moment, so as to switch from the droop control mode to the virtual synchronous control mode;

[0023] When the target meshing control mode is the droop control mode, the current inner loop of the droop control is initialized according to the output result of the virtual synchronous control at the switching moment, and a ramp signal is constructed to switch from the virtual synchronous control mode to the droop control mode.

[0024] In one embodiment, the step of determining the inverter control reference parameters based on the target grid-connected control mode and the inverter grid-connected point output voltage measurement parameters and the inverter grid-connected point output current measurement parameters includes:

[0025] When the target grid-type control mode is the virtual synchronous control mode, determining the inverter output power parameter according to the inverter grid-connected point output voltage measurement parameter and the inverter grid-connected point output current measurement parameter;

[0026] Establishing a virtual synchronous front-stage control equation based on a first droop coefficient parameter, a virtual moment of inertia, a virtual damping coefficient, and a virtual synchronous machine rated parameter, and inputting the inverter output power parameter into the virtual synchronous front-stage control equation to obtain a reference voltage;

[0027] Based on the voltage outer loop control coefficient, the current inner loop control coefficient, and the reference voltage, the voltage outer loop and current inner loop control equations are established, and the inverter outlet output current measurement parameters and the inverter grid-connected point output voltage measurement parameters are input into the voltage outer loop and current inner loop control equations to obtain the inverter output current reference parameters and the inverter output voltage reference parameters to determine the inverter control reference parameters.

[0028] In one embodiment, the step of determining the inverter control reference parameters based on the target grid-connected control mode and the inverter grid-connected point output voltage measurement parameters and the inverter grid-connected point output current measurement parameters includes:

[0029] When the target grid-type control mode is the droop control mode, determining the inverter output power parameter according to the inverter grid-connected point output voltage measurement parameter and the inverter grid-connected point output current measurement parameter;

[0030] A droop front-stage control equation is established based on the second droop coefficient parameter, the virtual moment of inertia, the virtual damping coefficient, and the virtual synchronous machine rated parameters, and the grid connection point angular velocity and the grid connection point voltage are input into the droop front-stage control equation to obtain a reference active power and a reference active power;

[0031] Based on the power outer loop control coefficient, the current inner loop control coefficient, the reference active power and the reference active power, the power outer loop and current inner loop control equations are established, and the inverter grid-connected point output voltage measurement parameters, the inverter grid-connected point output current measurement parameters and the inverter output power parameters are input into the power outer loop and current inner loop control equations to obtain the inverter output current reference parameters and the inverter output voltage reference parameters to determine the inverter control reference parameters.

[0032] In one embodiment, after the step of controlling the output current of the grid-type energy storage converter based on the grid-type fundamental current reference value and the grid-type harmonic current limit value, the method further includes:

[0033] When the frequency deviation or the voltage deviation meets the harmonic suppression module removal condition, deactivating the harmonic suppression strategy and activating the state of charge margin reservation strategy;

[0034] When the harmonic content and output current value corresponding to the harmonic spectrum of the power grid meet the harmonic suppression improvement conditions, increasing the harmonic suppression weight of the multi-objective optimization function;

[0035] Return to the step of obtaining grid status data.

[0036] In addition, to achieve the above-mentioned purpose, the present application also proposes a multi-scenario collaborative control device for a network-type energy storage converter, wherein the multi-scenario collaborative control device for a network-type energy storage converter comprises:

[0037] A data acquisition module is used to acquire grid status data and determine the grid connection point power, grid frequency, grid voltage and grid harmonic spectrum based on the grid status data;

[0038] A data processing module, configured to establish a multi-objective optimization function, an energy storage system state of charge constraint, and a converter output current constraint based on the grid connection point power, the grid frequency, the grid voltage, and the grid harmonic spectrum;

[0039] A data output module is configured to perform a multi-objective optimization solution based on the multi-objective optimization function, the energy storage system state of charge constraint, and the converter output current constraint to obtain a fundamental current reference value and a harmonic current limit value;

[0040] A data control module is used to control the output current of the grid-type energy storage converter based on the grid-type fundamental current reference value and the grid-type harmonic current limit value.

[0041] In addition, to achieve the above-mentioned purpose, the present application also proposes a multi-scenario collaborative control device for a grid-type energy storage converter, the device comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, the computer program being configured to implement the steps of the multi-scenario collaborative control method for a grid-type energy storage converter as described above.

[0042] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by the processor, the steps of the multi-scenario collaborative control method of the grid-type energy storage converter as described above are implemented.

[0043] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, it implements the steps of the multi-scenario collaborative control method of the grid-type energy storage converter as described above.

[0044] One or more technical solutions proposed in this application have at least the following technical effects:

[0045] By real-time monitoring of grid connection point power, grid frequency, grid voltage and harmonic spectrum, the grid operation status is determined. Based on the grid status data, a multi-objective optimization function is constructed that comprehensively considers power leveling, frequency regulation requirements and harmonic suppression. Weights are assigned to different control objectives, and multiple control objectives are comprehensively optimized. According to the charge state of the energy storage system and the output current of the converter, corresponding constraints are established to ensure the safe operation of the energy storage system and the overload of the converter. The multi-objective optimization function is solved and the fundamental current reference value and harmonic current limit value are obtained under the constraints to achieve a balance between power distribution and harmonic control. Based on the solution results, the output current of the energy storage converter is controlled so that the fundamental current meets the power support requirements and the harmonic current is limited to a reasonable range. The capacity conflict between grid control and harmonic control can be effectively coordinated, and the coordinated control of the energy storage converter in multiple scenarios is realized to ensure the stable operation of the grid and the power quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0047] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0048] Figure 1 A flowchart illustrating a first embodiment of a multi-scenario collaborative control method for a grid-type energy storage converter according to the present application;

[0049] Figure 2 A flowchart illustrating a second embodiment of a multi-scenario collaborative control method for a grid-type energy storage converter according to the present application;

[0050] Figure 3 This is a schematic diagram of the module structure of a multi-scenario collaborative control device for a grid-type energy storage converter according to an embodiment of the present application;

[0051] Figure 4 Schematic diagram of the device structure of the hardware operating environment involved in the multi-scenario collaborative control method of the grid-type energy storage converter in the embodiment of the present application.

[0052] The purpose, features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0053] It should be understood that the specific embodiments described herein are merely used to explain the technical solutions of the present application and are not intended to limit the present application.

[0054] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0055] The main solution of the embodiment of the present application is: obtaining grid status data, and determining the grid connection point power, grid frequency, grid voltage and grid harmonic spectrum based on the grid status data; establishing a multi-objective optimization function, energy storage system charge state constraints and converter output current constraints based on the grid connection point power, the grid frequency, the grid voltage and the grid harmonic spectrum; performing multi-objective optimization solution based on the multi-objective optimization function, the energy storage system charge state constraints and the converter output current constraints to obtain a fundamental current reference value and a harmonic current limit value; and controlling the output current of the grid-type energy storage converter based on the grid-type fundamental current reference value and the grid-type harmonic current limit value.

[0056] In this embodiment, for ease of description, the following description is made with the multi-scenario collaborative control device of the grid-type energy storage converter as the execution subject.

[0057] Most existing technologies use fixed weight allocation or module priority removal strategies to address the competitive relationship between the power margin required for grid-based control and the harmonic control capacity, thereby achieving a balance between multiple functions such as power support and harmonic suppression. However, harmonic limit settings based on static thresholds are difficult to adapt to dynamic changes in grid impedance and can easily lead to insufficient harmonic compensation or grid-based control failure in scenarios with fluctuating short-circuit ratios. Therefore, how to resolve the capacity conflict between grid-based control and harmonic control to achieve multi-scenario coordinated control has become an unresolved issue.

[0058] The present application provides a solution that determines the grid operation status by real-time monitoring of the grid connection point power, grid frequency, grid voltage and harmonic spectrum. Based on the grid status data, a multi-objective optimization function is constructed that comprehensively considers power leveling, frequency regulation requirements and harmonic suppression, weights are assigned to different control objectives, and multiple control objectives are comprehensively optimized. According to the charge state of the energy storage system and the output current of the converter, corresponding constraints are established to ensure the safe operation of the energy storage system and the overload of the converter. The multi-objective optimization function is solved, and the fundamental current reference value and harmonic current limit value are obtained under the constraints to achieve a balance between power distribution and harmonic control. Based on the solution results, the output current of the energy storage converter is controlled so that the fundamental current meets the power support requirements, while the harmonic current is limited to a reasonable range. The capacity conflict between grid control and harmonic control can be effectively coordinated, and the coordinated control of the energy storage converter in multiple scenarios is realized to ensure the stable operation of the grid and the power quality.

[0059] It should be noted that the execution subject of this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, mobile phone, etc., or an electronic device capable of implementing the above functions, a multi-scenario collaborative control device for a grid-type energy storage converter, etc. The following describes this embodiment and the following embodiments using a multi-scenario collaborative control device for a grid-type energy storage converter as an example.

[0060] Based on this, the embodiment of the present application provides a multi-scenario collaborative control method for a grid-type energy storage converter, referring to Figure 1 , Figure 1 This is a flow chart of the first embodiment of the multi-scenario collaborative control method for a grid-type energy storage converter according to the present application.

[0061] In this embodiment, the multi-scenario coordinated control method of the grid-type energy storage converter includes steps S10 to S40:

[0062] Step S10, acquiring grid status data, and determining grid connection point power, grid frequency, grid voltage, and grid harmonic spectrum based on the grid status data;

[0063] It should be noted that a grid-type energy storage inverter is an inverter that connects the energy storage system and the power grid and can actively control and stabilize the grid frequency and voltage. It does not rely on the voltage or frequency of the external grid and can independently supply power to the grid and maintain the stability of the grid. By simulating the external characteristics of a synchronous generator, the grid-type energy storage inverter can independently construct an AC voltage and frequency reference, solving the core defect of traditional phase-locked loop-dependent inverters that are prone to instability and disconnection in weak power grids. Especially in scenarios such as integrated wind, solar and storage microgrids and sending-end power grids with a high proportion of new energy access, grid-type control can significantly improve the system inertia support capability and voltage regulation accuracy through the characteristics of the power synchronization loop and voltage source.

[0064] Existing technologies face three major problems when dealing with the competitive relationship between power margin and harmonic control capacity in grid-type control. First, the harmonic limit setting based on a fixed threshold cannot flexibly adapt to the dynamic changes in grid impedance, especially when the grid short-circuit ratio fluctuates, which can easily lead to insufficient harmonic compensation or failure of grid-type control. Second, the mode switching between the virtual synchronous machine and the droop control is too dependent on the short-circuit ratio threshold set offline, lacks adaptive capabilities, and cannot be dynamically adjusted according to the attenuation of the energy storage system's state of charge or changes in the thermal stress of the converter, resulting in secondary power shocks during the switching process. Finally, due to the large calculation delay, the traditional model predictive control cannot meet the requirements of grid-type control for fast real-time optimization, resulting in low multi-objective collaborative efficiency. The existence of these problems makes it difficult to effectively achieve a balance between power margin and harmonic control, affecting the stability and economy of the system.

[0065] In addition, it should be noted that various sensors installed in the power grid, such as power sensors, voltage transformers, frequency meters and Fourier transform analyzers, can collect power grid status data such as power changes, voltage signals, current signals, frequency offsets, harmonic component data, etc.

[0066] It should be understood that the Point of Common Coupling (PCC) is the connection point where power generation equipment (such as distributed power generation systems, including solar photovoltaic power stations, wind farms, etc.) or energy storage systems are connected to the public power grid.

[0067] In addition, the grid power P _PCC The power transmitted at the grid connection point reflects the power exchange between the grid and the energy storage converter. The grid connection point voltage and current can be obtained from the grid status data. The grid connection point power can be calculated based on the grid connection point voltage and current using the power formula.

[0068] Additionally, the grid frequency f is the frequency of the AC current in the grid, which can be measured using frequency measurement equipment such as a frequency meter. The grid voltage U is the actual value of the AC voltage in the grid, which can be obtained by measuring the voltage amplitude of each phase of the grid. The grid harmonic spectrum is the frequency distribution of harmonics in the grid. The grid voltage and current signals collected from the grid status data can be processed using Fourier analysis to obtain the grid harmonic spectrum.

[0069] Step S20, establishing a multi-objective optimization function, energy storage system state of charge constraints, and converter output current constraints based on the grid connection point power, the grid frequency, the grid voltage, and the grid harmonic spectrum;

[0070] It should be noted that the multi-objective optimization function is a mathematical function constructed to comprehensively consider multiple control objectives during the energy storage converter control process. The multi-objective optimization function combines different control objectives, including power leveling, frequency modulation, and harmonic suppression, using weighting factors to achieve coordinated optimization among them.

[0071] In addition, the state of charge constraint of the energy storage system is to ensure the safe operation and service life of the energy storage system, and the restriction conditions set for its state of charge (SOC) include at least the lower limit of the SOC safety range SOC min and the upper limit of the safety range SOC max , to prevent the energy storage system from overcharging and discharging. The converter output current constraint is based on the performance and safety requirements of the energy storage converter, limiting the amplitude of the output current fundamental component and the amplitude of the output current harmonic components to ensure that the converter operates within the normal operating range and avoid overload.

[0072] It should be understood that before establishing the multi-objective optimization function, energy storage system state of charge constraints, and converter output current constraints based on the grid connection point power, grid frequency, grid voltage, and grid harmonic spectrum, the initial parameter-based predictive control rolling time domain T and control period Δt of the grid-connected energy storage converter control will be set, as well as the weight factors of the various control objectives of the multi-objective optimization function, namely the power smoothing weight α, the frequency regulation demand weight β, and the harmonic suppression weight γ.

[0073] In a feasible implementation, step S20 may include steps S21 to S25:

[0074] Step S21, determining a grid connection point active power historical data sequence, a frequency deviation, a voltage deviation, an output current fundamental component amplitude, and an output current harmonic component amplitude based on the grid connection point power, grid frequency, grid voltage, and grid harmonic spectrum;

[0075] It should be noted that the historical data series for active power at the grid connection point is a chronological sequence of historical measurements of active power at the grid connection point, used to analyze power trends. For example, if the grid connection point power is collected every 10 seconds over the past 10 minutes, a series of 60 data points will be formed. By collating the real-time grid connection point power collected over a preset time period, the historical data series for active power at the grid connection point can be obtained.

[0076] It should be understood that frequency deviation is the difference between the grid frequency and the rated frequency, reflecting the degree of deviation in the grid frequency. Voltage deviation is the difference between the grid voltage and the rated voltage at the grid connection point, reflecting the fluctuation of the grid voltage. The amplitude of the fundamental component of the output current is the current amplitude of the fundamental frequency in the converter output current, representing the main component of the current. The amplitude of the harmonic component of the output current is the current amplitude of the harmonic frequency component in the converter output current, reflecting the degree of harmonic pollution in the current. The amplitude of the fundamental component of the output current and the amplitude of the harmonic component of the output current can be determined from the grid harmonic spectrum obtained by Fourier analysis of the output current.

[0077] Step S22, predicting grid power fluctuations based on the historical data sequence of active power of the grid connection point;

[0078] It should be noted that grid power fluctuations refer to changes in active power within the grid over a period of time, including increases or decreases in power, as well as the magnitude and speed of these changes. Specifically, time series prediction methods, such as the Autoregressive Integrated Moving Average (ARIMA) model, can be used to analyze historical data sequences of active power at the grid connection point to predict grid power fluctuations over the next period of time. This allows for the development of control strategies in advance, enabling energy storage converters to better respond to power fluctuations and improving grid stability and reliability.

[0079] For example, the power fluctuation ΔP of the power grid in the future time domain T is predicted _forecast The formula is as follows:

[0080] ΔP _forecast =ARIMA(P _PCC_hist )

[0081] Where, P _PCC_hist Represents the historical data sequence of active power of the grid-connected point.

[0082] Step S23, constructing a multi-objective optimization function based on the grid power fluctuation, the frequency deviation, the voltage deviation, and the amplitude of the output current fundamental component;

[0083] It should be noted that the multi-objective optimization function includes a power smoothing term, a frequency regulation demand term, and a harmonic suppression term. Grid power fluctuations serve as inputs to the power smoothing term, frequency deviations and voltage deviations serve as inputs to the frequency regulation demand term, and the amplitude of the output current fundamental component serves as input to the harmonic suppression term. The power smoothing term minimizes predicted grid power fluctuations, enabling the energy storage system to dynamically adjust power output based on grid demand, thereby smoothing grid power variations and improving grid stability. The frequency regulation demand term minimizes frequency and voltage deviations to ensure that the grid frequency and voltage operate near rated values, improving grid power quality and reliability. The harmonic suppression term minimizes the amplitude of harmonic currents to reduce the impact of harmonics on the grid and ensure that grid power quality meets standards.

[0084] It should be understood that when constructing a multi-objective optimization function, power smoothing weights, frequency regulation demand weights and harmonic suppression weights will be set for the power smoothing item, frequency regulation demand item and harmonic suppression item respectively. According to the power smoothing weights, frequency regulation demand weights and harmonic suppression weights, the power smoothing item, frequency regulation demand item and harmonic suppression item are weighted and summed to obtain the minimization optimization target of the multi-objective optimization function, so as to achieve coordinated optimization of the energy storage converter among multiple control objectives.

[0085] Step S24, establishing a state of charge constraint for the energy storage system based on the current state of charge, energy storage output power, rated capacity, and control period of the energy storage system;

[0086] It should be noted that the energy storage system can store excess electrical energy when the grid load is low, and release electrical energy when the grid load is high or power generation is insufficient. The current state of charge is the percentage of the current remaining power of the energy storage system to the rated capacity, which reflects the energy state of the energy storage system and is used to judge the degree of charge of the energy storage system. The energy storage output power is the power output by the energy storage system to the grid or load, which can be positive (discharge) or negative (charge). The rated capacity is the maximum amount of electricity that can be stored specified when the energy storage system is designed, reflecting the energy storage capacity of the energy storage system. The control period is the time interval between two adjacent control actions of the grid-type energy storage converter, which is used to determine the frequency of the control calculation.

[0087] It should be understood that when establishing the state of charge constraint of the energy storage system, in addition to setting the lower limit of the safe range of the energy storage system state of charge SOC for the current state of charge of the energy storage system, min and the upper limit of the safety range SOC max , it will also establish constraints on the charge state of the energy storage system at two adjacent moments based on the energy storage system's energy storage output power, rated capacity, and control cycle to ensure that the charge state of the energy storage system is within a reasonable range, avoid overcharging or over-discharging, and extend the service life of the energy storage system.

[0088] Step S25 : establishing a converter output current constraint according to the amplitude of the output current fundamental component and the amplitude of the output current harmonic component.

[0089] It should be noted that the converter output current constraint is a limiting condition set for the converter output current. In the converter output current constraint, the converter maximum output current I max , limiting the sum of the amplitude of the output current fundamental component and the amplitude of the output current harmonic component to not exceed the maximum output current of the converter.

[0090] Step S30, performing a multi-objective optimization solution based on the multi-objective optimization function, the energy storage system state of charge constraint, and the converter output current constraint to obtain a fundamental current reference value and a harmonic current limit value;

[0091] It should be understood that the fundamental current reference value is the expected value for the amplitude of the fundamental component of the output current of the grid-type energy storage converter. It is used to guide the converter's current output at the fundamental frequency, ensuring power stability and voltage quality of the power grid. The harmonic current limit is the maximum allowable value set for the amplitude of the harmonic component in the output current of the grid-type energy storage converter. It is used to control harmonic pollution and ensure power quality of the power grid.

[0092] It should be noted that the multi-objective optimization function established in the previous steps, the energy storage system's state of charge constraints, and the converter output current constraints are used as input conditions. Using the optimization algorithm, we can find a point in the multi-dimensional optimization space that satisfies all constraints and achieves the optimal solution of the multi-objective optimization function (i.e., minimizes the multi-objective optimization function), thereby obtaining the fundamental current reference value and harmonic current limit. This multi-objective optimization solution can comprehensively balance the control requirements of power leveling, frequency modulation, harmonic suppression, and other aspects. While ensuring the safe operation of the energy storage system and the converter output current limit, it can effectively regulate the power and power quality of the power grid, thereby improving the stability and reliability of the entire power grid operation.

[0093] For example, the optimization problem solving formula established in steps S23 to S25 is as follows:

[0094]

[0095] Subject to:

[0096]

[0097] I base +I harmonic ≤I max

[0098] Where α represents the power smoothing weight, β represents the frequency regulation demand weight, γ represents the harmonic suppression weight, and J represents the multi-objective optimization function. _forecast represents the grid power fluctuation, f err 、U err Represent the frequency deviation and voltage deviation of the PCC node respectively. SOC(t) represents the state of charge of the energy storage system at the current moment, that is, the current state of charge of the energy storage system; SOC(t+1) represents the state of charge of the energy storage system at the next moment (t+1). batt Indicates the energy storage output power, E rated I represents the rated capacity of the energy storage system, Δt represents the control period, and η represents the efficiency factor. base Indicates the amplitude of the fundamental component of the output current, I harmonic Indicates the amplitude of the output current harmonic component, I max Indicates the maximum output current of the converter.

[0099] Step S40 : controlling the output current of the grid-type energy storage converter based on the grid-type fundamental current reference value and the grid-type harmonic current limit value.

[0100] It should be noted that the fundamental current reference value I of the grid-type energy storage converter in each control cycle can be obtained by the multi-objective rolling optimization power allocation of steps S10 to S30. base_ref and harmonic current limit I harmonic_max , the fundamental current reference value I base_ref and harmonic current limit I harmonic_max As a control target, the output current of the grid-type energy storage converter can be adjusted through corresponding control algorithms and strategies so that the fundamental current of the grid-type energy storage converter meets the reference value requirements while ensuring that the harmonic current does not exceed the limit.

[0101] Specifically, the fundamental current reference value can be tracked and the harmonic current can be limited through closed-loop control. The deviation between the fundamental current reference value and the actual output fundamental current is input into the current inner loop proportional-integral (PI) controller to generate a pulse width modulation control signal, and the converter switching device is adjusted so that the actual output fundamental current quickly tracks the fundamental current reference value. For harmonic current, the actual harmonic current can be compared with the harmonic current limit. If it exceeds the limit, the control parameters are adjusted through the harmonic suppression PI controller to reduce the harmonic current output. Ensure that the grid-type energy storage converter outputs current to the grid according to the optimized current amplitude and quality requirements, so as to effectively achieve the smoothing of grid power fluctuations, frequency and voltage regulation, and harmonic suppression, thereby improving the operating performance of the grid.

[0102] In a feasible implementation manner, after step S40, steps S50 to S70 may be further included:

[0103] Step S50: when the frequency deviation or the voltage deviation meets the harmonic suppression module removal condition, deactivate the harmonic suppression strategy and activate the state of charge margin reservation strategy;

[0104] It should be noted that the harmonic suppression module monitors the grid's harmonics in real time and dynamically adjusts the energy storage converter's output current through a control algorithm to suppress harmonic current injection, thereby improving the grid's power quality. The harmonic suppression module's disconnection conditions are pre-set. When frequency or voltage deviations reach certain thresholds, the harmonic suppression module must be disconnected, effectively disabling the harmonic suppression strategy to ensure safe and stable grid operation and the quality of power supply to critical equipment.

[0105] It should be understood that the conditions for removing the harmonic suppression module include a voltage deviation greater than a preset voltage deviation threshold or a frequency deviation greater than a preset frequency deviation threshold. The state of charge margin reservation strategy is a control strategy adopted to ensure that the energy storage system has sufficient state of charge margin to maintain its normal charging and discharging functions and extend its service life when the harmonic suppression module is disabled. The state of charge margin reservation strategy may include: limiting the energy storage charge and discharge power to a preset percentage of the rated value; and compressing the actual available range of the state of charge to a preset available range to avoid control failure caused by the SOC approaching the limit value.

[0106] For example, the harmonic suppression module removal condition can be when the voltage deviation exceeds 10% or the frequency deviation exceeds 0.5Hz. The state of charge margin reservation strategy can be: limiting the energy storage charge and discharge power to 80% of the rated value; and compressing the actual SOC usable range to 30%-80%. The control equation of the harmonic suppression module is as follows:

[0107]

[0108] Where K IHP and K IHI are the proportional coefficient and integral coefficient of the harmonic suppression PI controller in the harmonic suppression module respectively; i id_harmonic and i iq_harmonic The harmonic current measurement value of the grid-type energy storage converter is measured by the harmonic current limit value I harmonic_max The d-axis component value and q-axis component value of the harmonic current after the limiting link are the maximum values; u id_ref_harmonic and u iq_ref_harmonic It represents the reference value of the d-axis component and q-axis component of the grid-type energy storage converter output voltage.

[0109] Step S60, when the harmonic content and output current value corresponding to the harmonic spectrum of the power grid meet the harmonic suppression improvement conditions, increasing the harmonic suppression weight of the multi-objective optimization function;

[0110] It should be noted that the harmonic content corresponding to the grid harmonic spectrum is the amplitude of the harmonic current in the grid, reflecting the degree of harmonic pollution in the grid. It can be expressed as the ratio of the amplitude of each harmonic to the amplitude of the fundamental wave. The output current value is the actual output current of the energy storage converter, including the fundamental current and harmonic current. The condition for improving harmonic suppression is that when the harmonic content corresponding to the grid harmonic spectrum is greater than the preset harmonic content threshold, and the output current value of the converter is less than the preset current ratio of the converter's maximum output current, in order to better suppress harmonic pollution, it is necessary to improve the harmonic suppression weight in the multi-objective optimization function.

[0111] For example, the harmonic suppression improvement condition can be that the harmonic content corresponding to the grid harmonic spectrum is greater than 5% and the output current value is less than the maximum output current I max When the harmonic content and output current value corresponding to the grid harmonic spectrum meet the conditions for improving harmonic suppression, the harmonic suppression weight γ will be increased to increase harmonic circulating current injection.

[0112] Step S70, returning to the step of obtaining grid status data.

[0113] It should be noted that the above steps S50 to S60 will be performed on the basis of multi-objective rolling optimization power allocation of the grid-type energy storage converter each time. If it is detected in real time that the frequency deviation and voltage deviation of the power grid meet the harmonic suppression module removal conditions, or if it is detected in real time that the harmonic content corresponding to the power grid harmonic spectrum and the output current value of the converter meet the harmonic suppression improvement conditions, the charge state margin reservation strategy will be activated accordingly, or the harmonic suppression weight of the multi-objective optimization function will be improved, so that the control strategy of the grid-type energy storage converter is always optimized and adjusted based on the latest power grid information, adapting to the dynamic changes of the power grid in a timely manner, improving the response speed and control accuracy of the control process, and ensuring the stable operation of the power grid and the continuous optimization of the power quality.

[0114] It should be understood that when the duration of controlling the output current of the grid-type energy storage converter based on the grid-type fundamental current reference value and the grid-type harmonic current limit reaches the control period, the step of obtaining the grid status data will be returned to enter the next round of control process of the grid-type energy storage converter, providing a real-time basis for subsequent multi-objective optimization and control, ensuring that the entire control system can respond and adjust in time according to changes in the grid, and realize dynamic closed-loop control of the grid.

[0115] This embodiment monitors the grid connection point power, grid frequency, grid voltage, and harmonic spectrum in real time to determine the grid operating status. Based on the grid status data, a multi-objective optimization function is constructed that comprehensively considers power leveling, frequency regulation requirements, and harmonic suppression. Weights are assigned to different control objectives, and multiple control objectives are comprehensively optimized. Based on the charge state of the energy storage system and the output current of the converter, corresponding constraints are established to ensure the safe operation of the energy storage system and the overload of the converter. The multi-objective optimization function is solved to obtain the fundamental current reference value and harmonic current limit value under the constraints, achieving a balance between power distribution and harmonic control. Based on the solution, the output current of the energy storage converter is controlled so that the fundamental current meets the power support requirement while limiting the harmonic current to a reasonable range. This can effectively coordinate the capacity conflict between grid-type control and harmonic control, realize the coordinated control of the energy storage converter in multiple scenarios, and ensure the stable operation of the grid and power quality.

[0116] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above embodiment 1 can be referred to the above introduction and will not be described in detail later. Figure 2 Before step S40, the multi-scenario coordinated control method of the grid-type energy storage converter further includes steps S301 to S303:

[0117] Step S301: Determine transient voltage mutation flag parameters, transient frequency disturbance flag parameters, grid strength assessment parameters, frequency deviation duration parameters, and energy storage system state of charge parameters based on grid state data to obtain grid-type control mode switching information;

[0118] It should be noted that the transient voltage mutation mark parameter is a parameter used to characterize whether a transient voltage mutation occurs in the power grid, which can be judged by the voltage change rate or the voltage drop amplitude. The transient frequency disturbance mark parameter is a parameter used to characterize whether a transient frequency disturbance occurs in the power grid, which can be judged by the frequency change rate or the frequency deviation amplitude. The power grid strength assessment parameter is a parameter used to measure the power grid's ability to resist disturbances, which can be expressed by the ratio of the grid connection point short-circuit capacity to the rated capacity of the converter, that is, the short-circuit ratio. The grid connection point short-circuit capacity of the grid connection point can be estimated by real-time collection of grid current and voltage data. The grid connection point short-circuit capacity indicates the maximum power or current capacity that the grid can withstand in the event of a short-circuit fault. The frequency deviation duration parameter is the duration that the frequency deviation of the power grid exceeds the set threshold. The energy storage system charge state parameter is the current charge state of the energy storage system.

[0119] It should be understood that by analyzing and calculating the grid status data such as the grid connection point voltage, current, frequency and energy storage system charge state collected in real time, the transient voltage mutation mark parameters, transient frequency disturbance mark parameters, grid strength assessment parameters, frequency deviation duration parameters and energy storage system charge state parameters can be determined to obtain the grid-forming control mode switching information to determine whether the grid-forming control mode needs to be switched.

[0120] Step S302: When the network-type control mode switching information meets a preset switching condition, determining that the target network-type control mode is a virtual synchronous control mode or a droop control mode;

[0121] It should be noted that the target grid-type control mode includes virtual synchronous control mode and droop control mode, which is the grid-type control mode that the grid-type energy storage converter should currently maintain. In the virtual synchronous control mode, the operating characteristics of the synchronous generator will be simulated to provide inertia and damping support for the grid. It is suitable for grid disturbances (such as voltage mutations, frequency fluctuations) or weak grid scenarios to provide frequency regulation and power response. In the droop control mode, the output power of the inverter will be adjusted based on the active-frequency droop characteristics and the reactive-voltage droop characteristics. It is suitable for normal grid operation or low energy storage SOC to ensure power balance between different grid-connected power generation units in the energy storage system.

[0122] It should be understood that the preset switching conditions are preset criteria for determining whether a grid-type control mode switch is required, including conditions for switching from a virtual synchronous control mode to a droop control mode, and conditions for switching from a droop control mode to a virtual synchronous control mode. Specifically, whether to activate the virtual synchronous control mode as the target grid-type control mode can be determined based on the transient voltage mutation flag parameter, transient frequency disturbance flag parameter, or grid strength assessment parameter in the grid-type control mode switching information; and whether to activate the droop control mode to switch to the target grid-type control mode can be determined based on the frequency deviation duration parameter or energy storage system state of charge parameter in the grid-type control mode switching information.

[0123] Specifically, when a transient voltage mutation, transient frequency disturbance, or grid strength below a set value is determined based on a transient voltage mutation flag parameter, a transient frequency disturbance flag parameter, or a grid strength assessment parameter, the virtual synchronous control mode is activated to provide grid support. When a frequency deviation duration parameter or an energy storage system state of charge parameter determines that the frequency deviation has been below a set value for a continuous preset duration or the energy storage system's current state of charge is less than a preset state of charge, droop control is activated to smooth out renewable energy fluctuations. For example, the preset duration can be 30 seconds, and the preset state of charge can be 30%.

[0124] Step S303 : Based on the target grid-type control mode, inverter control reference parameters are determined according to inverter grid-connected point output voltage measurement parameters and inverter grid-connected point output current measurement parameters.

[0125] It should be noted that the inverter grid-connected point output voltage measurement parameter may include the measured value u of the inverter PCC node output voltage d-axis component od , the measured value u of the q-axis component of the inverter PCC node output voltage od The inverter grid-connected point output current measurement parameters may include the measured value i of the inverter PCC node output current d-axis component od , the measured value of the q-axis component of the inverter PCC node output voltage i oq The inverter control reference parameters include the inverter output current reference parameters and the inverter output voltage reference parameters, which are used to control the inverter output to meet the requirements of the power grid and achieve the control goal of multi-scenario coordinated control of the grid-type energy storage converter.

[0126] In this implementation, adaptive switching between virtual synchronous machines and droop control is achieved based on grid transient indicators, short-circuit ratio thresholds, and energy storage charge status. This allows for coordinated control of multiple scenarios, including smoothing of renewable energy output fluctuations, grid voltage / frequency support, and harmonic control, thereby improving the economic efficiency of the energy storage system.

[0127] In a feasible implementation, step S303 may include steps B11 to B13:

[0128] Step B11, when the target grid configuration control mode is the virtual synchronous control mode, determining the inverter output power parameter according to the inverter grid connection point output voltage measurement parameter and the inverter grid connection point output current measurement parameter;

[0129] It should be noted that the control process under the virtual synchronous control mode includes a virtual synchronization link, a voltage outer loop link, and a current inner loop link. Among them, the virtual synchronization link is used to simulate the inertia and damping characteristics of a traditional synchronous generator to ensure the frequency and phase stability of the energy storage system. The voltage outer loop link is used to ensure voltage stability on the grid side. The current inner loop link is used to ensure accurate current output. The three links work together to improve the dynamic performance and stability of the energy storage system as a whole.

[0130] It should be understood that the inverter output power parameters can be calculated based on the measured voltage and current parameters of the inverter grid-connected point output, that is, the inverter grid-connected point output voltage measurement parameters and the inverter grid-connected point output current measurement parameters. The inverter output power parameters include the inverter output active power P e And the inverter output reactive power Q e .

[0131] For example, the inverter outputs active power P e And the inverter output reactive power Q e The calculation formula is as follows:

[0132] P e =3 / 2(u od i od +u oq i oq )

[0133] Q e =3 / 2(u oq i od -u od i oq )

[0134] Where u od represents the measured value of the d-axis component of the inverter PCC node output voltage; u oq represents the measured value of the q-axis component of the inverter PCC node output voltage; i od represents the measured value of the d-axis component of the inverter PCC node output current; i oq Represents the measured value of the q-axis component of the inverter PCC node output voltage.

[0135] Step B12: establishing a virtual synchronous front-stage control equation based on the first droop coefficient parameter, the virtual moment of inertia, the virtual damping coefficient, and the virtual synchronous machine rated parameters, and inputting the inverter output power parameter into the virtual synchronous front-stage control equation to obtain a reference voltage;

[0136] It should be noted that the first droop coefficient parameter is a coefficient used to characterize the droop characteristics between active power and frequency, and reactive power and voltage in the virtual synchronous control mode, including the active-frequency droop coefficient K ω and voltage-reactive power droop coefficient K Q . The virtual moment of inertia is a parameter that simulates the moment of inertia of the synchronous generator rotor, and is used to reflect the inertial response capability of the energy storage converter to changes in grid frequency. The virtual damping coefficient is a parameter that simulates the damping characteristics of the synchronous generator, and is used to reflect the damping effect of the energy storage converter on changes in grid frequency and voltage. The rated parameters of the virtual synchronous machine include the rated value of the active power output of the power support type virtual synchronous machine, the rated value of the reactive power, the rated voltage of the grid connection point, and the rated angular velocity of the grid connection point, which are used to define the working state of the virtual synchronous machine under normal operating conditions. The virtual synchronous front-stage control equation is the control equation used by the virtual synchronous link in the virtual synchronous control mode to simulate the motion equation of the synchronous generator rotor.

[0137] It should be understood that a virtual synchronous pre-stage control equation can be established based on the first droop coefficient parameter, the virtual moment of inertia, the virtual damping coefficient, and the rated parameters of the virtual synchronous machine. Substituting the inverter output power parameter obtained in step B11 as an input into this control equation, a reference voltage can be calculated. The reference voltage is the output voltage amplitude of the voltage-support virtual synchronous machine, obtained based on the inverter output power parameter and the virtual synchronous control requirements. In virtual synchronous control, by simulating the voltage-support virtual synchronous machine to adjust the inverter output voltage amplitude and phase, voltage support can be provided to the power grid. In particular, when the grid voltage fluctuates or fails, it can quickly respond and maintain voltage stability.

[0138] For example, the formula of the virtual synchronous front-stage control equation is as follows:

[0139]

[0140] Where K ω Indicates the active power-frequency droop coefficient, K Q P represents the voltage-reactive power droop coefficient; J represents the virtual moment of inertia; D represents the virtual damping coefficient. N , Q N They represent the rated value of the active power and reactive power output of the power support type virtual synchronous machine respectively; U N Indicates the rated voltage of the grid connection point; ω N Indicates the rated angular velocity of the grid connection point. e , Q e Respectively represent the inverter output active power and reactive power. ω represents the virtual angular velocity of the voltage support type virtual synchronous machine. U ref Indicates the output voltage amplitude of the voltage-supported virtual synchronous machine, that is, the reference voltage.

[0141] Step B13, establishing voltage outer loop and current inner loop control equations based on the voltage outer loop control coefficient, the current inner loop control coefficient, and the reference voltage, and inputting the inverter outlet output current measurement parameters and the inverter grid-connected point output voltage measurement parameters into the voltage outer loop and current inner loop control equations to obtain the inverter output current reference parameters and the inverter output voltage reference parameters to determine the inverter control reference parameters.

[0142] It should be noted that the voltage outer loop control coefficient is a control parameter used by the voltage outer loop PI controller to adjust the deviation between the inverter output voltage and the reference voltage, and may include the voltage outer loop proportional coefficient K UP And the voltage outer loop integral coefficient K UI, used to achieve fast response and precise control of voltage. The current inner loop control coefficient is the control parameter used by the current inner loop PI controller to adjust the deviation between the inverter output current and the reference current. It can also include the current inner loop proportional coefficient K IP and the current inner loop integral coefficient K II , used to achieve fast response and precise control of current. According to the reference voltage U ref The reference value U of the d-axis component of the inverter PCC node voltage can be calculated by combining the virtual phase angle θ of the voltage support type virtual synchronous machine d_ref and the reference value U of the q-axis component of the inverter PCC node voltage q_ref .

[0143] In addition, the voltage outer loop and current inner loop control equations are control equations established based on the voltage outer loop and current inner loop control principles, which are used to achieve precise control of the inverter output voltage and current. The inverter output current measurement parameters are the current parameters measured at the inverter output, including the measured value i of the inverter output current d-axis component. id and the measured value of the q-axis component of the inverter output current i iq The inverter grid-connected point output voltage measurement parameters include the measured value u of the inverter PCC node output voltage d-axis component od and the measured value u of the q-axis component of the inverter PCC node output voltage oq .

[0144] In addition, the inverter output current reference parameter and the inverter output voltage reference parameter are the expected values ​​of the inverter output current and output voltage determined according to the control requirements, and are used to control the output of the inverter to meet the needs of the power grid and the control target. The inverter output current reference parameter includes the reference value i of the inverter output current d-axis component id_ref and the reference value i of the inverter output current q-axis component iq_ref The inverter output voltage reference parameters include the reference value u of the inverter output voltage d-axis component id_ref and the reference value u of the inverter output current q-axis component iq_ref .

[0145] It should be understood that based on the voltage outer loop control coefficient and the current inner loop control coefficient, combined with the reference voltage obtained in step B12, the voltage outer loop and current inner loop control equations are established. The inverter outlet output current measurement parameters and the inverter grid-connected point output voltage measurement parameters are input as feedback signals into the voltage outer loop and current inner loop control equations. The inverter output current reference parameters and the inverter output voltage reference parameters are calculated by the control algorithm, and the control reference parameters of the inverter can be determined. In the voltage outer loop control link, the reference value of the inverter output current is calculated based on the deviation between the reference voltage and the actual output voltage. In the current inner loop control link, the control signal is calculated based on the deviation between the reference value of the inverter output current and the actual output current of the inverter. The output of the inverter is adjusted so that its output current and voltage gradually approach the reference value, thereby achieving precise control of the inverter output.

[0146] For example, the voltage outer loop and current inner loop control equations are as follows:

[0147]

[0148] Where K UP , K UI , K IP , K II Respectively represent the voltage outer loop proportional coefficient, voltage outer loop integral coefficient, current inner loop proportional coefficient, and current inner loop integral coefficient. d_ref 、U q_ref Respectively represent the reference values ​​of the d-axis and q-axis components of the inverter PCC node voltage; u od 、u oq are the measured values ​​of the d-axis and q-axis components of the inverter PCC node output voltage, respectively. id_ref 、i iq_ref Respectively represent the reference values ​​of the d-axis and q-axis components of the inverter output current; u id_ref 、u iq_ref Respectively represent the reference values ​​of the d-axis and q-axis components of the inverter output voltage. id 、i iq Respectively represent the measured values ​​of the d-axis and q-axis components of the inverter output current. s is a complex variable, representing the integral link of the PI controller; ω N Indicates the rated angular velocity of the grid connection point; L f Indicates the filter inductance on the inverter side of the filter.

[0149] It should be understood that the voltage outer loop and current inner loop control equations are composed of the voltage outer loop control equation and the current inner loop control equation. The voltage outer loop control equation is based on the reference value of the voltage outer loop (U d_ref 、U q_ref ) and the actual output voltage (u od 、u oq) deviation to calculate the reference current value of the inner current loop (i id_ref 、i iq_ref ), the current inner loop control equation is then based on the reference current value of the current inner loop (i id_ref 、i iq_ref ) and the actual output current (i id 、i iq ) deviation to calculate the reference voltage value of the current inner loop (u id_ref 、u iq_ref ) to adjust the output current and voltage of the inverter to gradually approach the reference value, thereby achieving precise control of the inverter output.

[0150] In another feasible implementation, step S303 may include steps B21 to B23:

[0151] Step B21, when the target grid-type control mode is the droop control mode, determining the inverter output power parameter according to the inverter grid-connected point output voltage measurement parameter and the inverter grid-connected point output current measurement parameter;

[0152] It should be noted that the control process under the droop control mode includes a droop link, a power outer loop link, and a current inner loop link. Among them, the droop link is used to associate the active power and reactive power output by the energy storage system with the deviation of its voltage and frequency to achieve autonomous distribution of grid power and frequency stability. The power outer loop link is used to compare the power set by the energy storage system with the actual output power, generate a current reference value, and guide the operation of the current inner loop. The current inner loop link is used to quickly adjust the output of the inverter to be consistent with the reference value based on the current reference value generated by the power outer loop.

[0153] It should be understood that the inverter output power parameters can be calculated based on the measured voltage and current parameters, namely the inverter grid-connected point output voltage measurement parameters and the inverter grid-connected point output current measurement parameters, including the inverter output active power P e And the inverter output reactive power Q e .

[0154] For example, the inverter outputs active power P e And the inverter output reactive power Q e The calculation formula is as follows:

[0155] P e =3 / 2(u od i od +u oq i oq )

[0156] Q e =3 / 2(u oq i od -uod i oq )

[0157] Where u od represents the measured value of the d-axis component of the inverter PCC node output voltage; u oq represents the measured value of the q-axis component of the inverter PCC node output voltage; i od represents the measured value of the d-axis component of the inverter PCC node output current; i oq Represents the measured value of the q-axis component of the inverter PCC node output voltage.

[0158] Step B22: establishing a droop front-stage control equation based on the second droop coefficient parameter, the virtual moment of inertia, the virtual damping coefficient, and the virtual synchronous machine rated parameters, and inputting the grid connection point angular velocity and the grid connection point voltage into the droop front-stage control equation to obtain a reference active power and a reference active power;

[0159] It should be noted that the second droop coefficient parameter is a coefficient used to characterize the droop characteristics between active power and frequency, and reactive power and voltage in the droop control mode, including the active-frequency droop coefficient K ω and reactive-voltage droop coefficient K U . The virtual moment of inertia is a parameter that simulates the moment of inertia of the synchronous generator rotor, and is used to reflect the inertial response capability of the energy storage converter to changes in grid frequency. The virtual damping coefficient is a parameter that simulates the damping characteristics of the synchronous generator, and is used to reflect the damping effect of the energy storage converter on changes in grid frequency and voltage. The rated parameters of the virtual synchronous machine include the rated value of the active power output of the power support type virtual synchronous machine, the rated value of the reactive power, the rated voltage of the grid connection point, and the rated angular velocity of the grid connection point, which are used to define the working state of the virtual synchronous machine under normal operating conditions.

[0160] Additionally, the pre-droop control equations are used to dynamically adjust the output power of the energy storage system during the droop control mode. These equations consist of the active power droop control equation and the reactive power droop control equation. The grid connection point angular velocity is the rate of change of the grid voltage phase, as measured in real time by the phase-locked loop (PLL), reflecting the actual grid frequency. The grid connection point voltage is the grid voltage amplitude at the connection point, reflecting the grid voltage level.

[0161] It should be understood that the active power droop control equation and the reactive power droop control equation can be established based on the second droop coefficient parameter, the virtual moment of inertia, the virtual damping coefficient and the rated parameters of the virtual synchronous machine. Substituting the grid connection point angular velocity into the active power droop control equation, the reference active power can be obtained by calculation. Substituting the grid connection point voltage into the reactive power droop control equation, the reference reactive power can be obtained by calculation. The reference active power is the reference value of the active power output of the power support type virtual synchronous machine, which is used to guide the active power output of the energy storage converter. By adjusting the output power of the energy storage converter to be close to the reference active power, the grid frequency can be regulated and the grid frequency can be maintained stable. The reference reactive power is the reference value of the reactive power output of the power support type virtual synchronous machine, which is used to guide the reactive power output of the energy storage converter. By adjusting the output power of the energy storage converter to be close to the reference reactive power, the grid voltage can be regulated and the grid voltage can be maintained stable.

[0162] For example, the droop front stage control equation is as follows:

[0163]

[0164] Where K ω Indicates the active power-frequency droop coefficient; K U P represents the reactive-voltage droop coefficient; J represents the virtual moment of inertia; D represents the virtual damping coefficient. N , Q N They represent the rated value of the active power and reactive power output of the power support type virtual synchronous machine respectively; ω N Indicates the rated angular velocity of the grid connection point; U N Indicates the rated voltage of the grid connection point. ω indicates the angular velocity of the grid connection point; U m Indicates the grid connection point voltage. ref , Q ref They represent the reference values ​​of active and reactive power output by the power support type virtual synchronous machine respectively.

[0165] Step B23, establishing power outer loop and current inner loop control equations based on the power outer loop control coefficient, the current inner loop control coefficient, the reference active power and the reference active power, and inputting the inverter grid-connected point output voltage measurement parameters, the inverter grid-connected point output current measurement parameters and the inverter output power parameters into the power outer loop and current inner loop control equations to obtain the inverter output current reference parameters and the inverter output voltage reference parameters to determine the inverter control reference parameters.

[0166] It should be noted that the power outer loop control coefficient is a control parameter used by the power outer loop PI controller to adjust the power deviation between the inverter output power and the reference power, which may include the power outer loop proportional coefficient K PPand the power outer loop integral coefficient K PI , where K PP Determines the response speed of power deviation, K PI The current inner loop control coefficient is a control parameter used by the current inner loop PI controller to adjust the current deviation between the inverter output current and the reference current, which can include the current inner loop proportional coefficient K IP and the current inner loop integral coefficient K II , where K IP Determines the response speed of current deviation, K II The power outer loop and current inner loop control equations are established based on the power outer loop and current inner loop control principles, and are used to achieve precise control of the inverter output voltage and current.

[0167] In addition, the inverter output current reference parameter and the inverter output voltage reference parameter are the expected values ​​of the inverter output current and output voltage determined according to the control requirements, and are used to control the output of the inverter to meet the needs of the power grid and the control target. The inverter output current reference parameter includes the reference value i of the inverter output current d-axis component id_ref and the reference value i of the inverter output current q-axis component iq_ref The inverter output voltage reference parameters include the reference value u of the inverter output voltage d-axis component id_ref and the reference value u of the inverter output current q-axis component iq_ref .

[0168] It should be understood that based on the power outer loop control coefficient and the current inner loop control coefficient, combined with the reference active power and reference active power obtained in step B22, the power outer loop and current inner loop control equations can be established. The inverter grid-connected point output voltage measurement parameters, the inverter grid-connected point output current measurement parameters, and the inverter output power parameters are input as feedback signals into the power outer loop and current inner loop control equations. The inverter output current reference parameters and the inverter output voltage reference parameters are calculated by the control algorithm to determine the control reference parameters of the inverter. In the power outer loop control link, the reference value of the inverter output current is calculated based on the deviation between the reference power and the actual output power. In the current inner loop control link, the control signal is calculated based on the deviation between the reference value of the inverter output current and the actual output current of the inverter. The output of the inverter is adjusted so that its output current and voltage gradually approach the reference value, thereby achieving precise control of the inverter output.

[0169] For example, the control equations of the power outer loop and the current inner loop are as follows:

[0170]

[0171] Where KPP , K PI , K IP , K II They represent the power outer loop proportional coefficient, power outer loop integral coefficient, current inner loop proportional coefficient, and current inner loop integral coefficient respectively. ref , Q ref Respectively represent the reference values ​​of active and reactive power output by the power support type virtual synchronous machine. e , Q e Respectively represent the inverter output active power and reactive power. id_ref 、i iq_ref Respectively represent the reference values ​​of the d-axis and q-axis components of the inverter output current; u id_ref 、u iq_ref Respectively represent the reference values ​​of the d-axis and q-axis components of the inverter output voltage. od 、i oq Represent the measured values ​​of the d-axis and q-axis components of the PCC node output current respectively. s is a complex variable, representing the integral link of the PI controller; ω N Indicates the rated angular velocity of the grid connection point; L f Indicates the filter inductance on the inverter side of the filter.

[0172] It should be understood that the power outer loop and current inner loop control equations are composed of the power outer loop control equation and the current inner loop control equation. The power outer loop equation is based on the reference value of the power outer loop (P ref , Q ref ) and actual output power (P e , Q e ) deviation to calculate the reference current value of the inner current loop (i id_ref 、i iq_ref ), the current inner loop control equation is then based on the reference current value of the current inner loop (i id_ref 、i iq_ref ) and the actual output current (i od 、i oq ) deviation to calculate the reference voltage value of the current inner loop (u id_ref 、u iq_ref ) to adjust the output current and voltage of the inverter to gradually approach the reference value, thereby achieving precise control of the inverter output.

[0173] In a feasible implementation manner, before step S303, steps A11 to A12 may also be included:

[0174] Step A11, when the target network control mode is the virtual synchronous control mode, initializing the current inner loop of the virtual synchronous control according to the output result of the droop control at the switching moment, so as to switch from the droop control mode to the virtual synchronous control mode;

[0175] It should be noted that, according to the judgment result of the target grid-type control mode, when switching from the droop control mode to the virtual synchronous control mode, a smooth transition is achieved by assigning the state quantity in the control system. The output result of the droop control is the output value of the current inner loop in the droop control mode at the switching moment, which may include the output current measurement parameters of the inverter grid-connected point (i od 、i oq The current inner loop of the virtual synchronous control is an integral link used to accurately control the output current to track the reference current under the virtual synchronous control mode. By accumulating the current deviation, the control signal is adjusted to eliminate the current steady-state error and ensure accurate current control.

[0176] It should be understood that when the target network control mode is determined to be the virtual synchronous control mode, the virtual angular velocity and phase will be adjusted to be consistent with the droop control in the pre-synchronization link, and the output value of the droop control current inner loop at the switching moment will be obtained, that is, the measured values ​​of the d-axis and q-axis components of the PCC node output current. The output value of the current inner loop in the droop control mode at the switching moment (i od 、i oq ) is assigned to the initial value of the current inner loop in the virtual synchronous control mode (i id 、i iq ) to ensure that the output voltage command value of the converter remains unchanged during the switching process.

[0177] Step A12, when the target grid-type control mode is the droop control mode, initialize the current inner loop of the droop control according to the output result of the virtual synchronous control at the switching moment, and construct a ramp signal to switch from the virtual synchronous control mode to the droop control mode.

[0178] It should be noted that, based on the judgment result of the target network control mode, when switching from the virtual synchronous control mode to the droop control mode, a ramp function transition is used to avoid power mutation. The ramp function starts from an initial value and smoothly transitions to the target value at a certain rate. The output result of the virtual synchronous control at the switching moment is the output value of the virtual synchronous control current inner loop at the switching moment, which may include the inverter output current measurement parameter (i id 、i iq The droop control current inner loop is an integral element used to precisely control the output current to track the reference current in droop control mode. By accumulating current deviations, it adjusts the control signal, eliminates steady-state current errors, and ensures precise current control. The ramp signal controls the rate of change of the power reference value to avoid sudden power changes during switching. This is achieved through a ramp function.

[0179] It should be understood that when the target grid control mode is determined to be the droop control mode, the frequency and phase of the grid voltage will be continuously tracked through the phase-locked loop to ensure that the output voltage of the converter is synchronized with the grid voltage during the switching process. At the same time, the output value of the current inner loop link (i id 、i iq ) is assigned to the initial value of the current inner loop in the droop control mode (i od 、i oq ) to ensure that the voltage command value of the converter output remains unchanged during the switching process. The reference active power and reference active power in the output result of the droop link front stage control at the switching moment are used as the target value of the ramp function, and the power (P e , Q e ) as the initial value, construct the ramp signal, and within the preset ramp signal duration, the ramp signal increases linearly from the initial value to the target value. The power outer loop reference value (P ref , Q ref ) The ramp signal is applied for a predetermined duration, and then the reference active power and reference active power of the preceding stage output of the droop control are applied. For example, the predetermined duration of the ramp signal may be 10 seconds. The power reference value of the power outer loop is applied for 10 seconds from the switching moment using the ramp signal. After 10 seconds, the power reference value is applied to the preceding stage control output of the droop control.

[0180] In this embodiment, control reference parameters are dynamically generated based on the target grid-type control mode, combined with the current inner loop integral initialization and ramp transition strategy to ensure current continuity and smooth power transition during mode switching, avoid secondary power shocks, and achieve coordinated optimization of grid stability, power quality and energy storage economy.

[0181] This embodiment uses real-time monitoring of grid status data to determine relevant parameters such as transient voltage mutations, transient frequency disturbances, grid strength, frequency deviation duration, and the energy storage system charge state. This allows accurate judgment of grid operation status, determines grid-type control mode switching information based on these parameters, and promptly switches between virtual synchronous control mode and droop control mode when preset switching conditions are met. The inverter control reference parameters are determined based on the target control mode and the output voltage and current measurement parameters of the inverter grid connection point. This solves the mode switching lag problem caused by reliance on static thresholds in traditional control, achieves adaptive switching between virtual synchronous control and droop control, and enables precise control of the inverter to ensure stable grid operation.

[0182] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the multi-scenario collaborative control method of the grid-type energy storage converter of the present application. More forms of simple transformations based on this technical concept are all within the scope of protection of the present application.

[0183] This application also provides a multi-scenario collaborative control device for a network-type energy storage converter, please refer to Figure 3 The multi-scenario collaborative control device for a grid-type energy storage converter includes:

[0184] The data acquisition module 10 is used to acquire grid status data and determine the grid connection point power, grid frequency, grid voltage and grid harmonic spectrum based on the grid status data;

[0185] A data processing module 20 is configured to establish a multi-objective optimization function, an energy storage system state of charge constraint, and a converter output current constraint based on the grid connection point power, the grid frequency, the grid voltage, and the grid harmonic spectrum;

[0186] A data output module 30 is configured to perform a multi-objective optimization solution based on the multi-objective optimization function, the energy storage system state of charge constraint, and the converter output current constraint to obtain a fundamental current reference value and a harmonic current limit value;

[0187] The data control module 40 is configured to control the output current of the grid-type energy storage converter based on the grid-type fundamental current reference value and the grid-type harmonic current limit value.

[0188] In one embodiment, the data processing module 20 is further used to determine the grid point active power historical data sequence, frequency deviation, voltage deviation, output current fundamental component amplitude and output current harmonic component amplitude based on the grid point power, grid frequency, grid voltage and grid harmonic spectrum; predict grid power fluctuation based on the grid point active power historical data sequence; construct a multi-objective optimization function based on the grid power fluctuation, the frequency deviation, the voltage deviation and the output current fundamental component amplitude; establish energy storage system charge state constraints based on the current state of charge of the energy storage system, energy storage output power, rated capacity and control period; establish converter output current constraints based on the output current fundamental component amplitude and the output current harmonic component amplitude.

[0189] In one embodiment, the data control module 40 is further used to determine a transient voltage mutation flag parameter, a transient frequency disturbance flag parameter, a grid strength assessment parameter, a frequency deviation duration parameter, and a storage system state of charge parameter based on the grid status data to obtain grid-type control mode switching information; when the grid-type control mode switching information meets the preset switching conditions, determine the target grid-type control mode as a virtual synchronous control mode or a droop control mode; based on the target grid-type control mode, determine the inverter control reference parameters according to the inverter grid-connected point output voltage measurement parameters and the inverter grid-connected point output current measurement parameters.

[0190] In one embodiment, the data control module 40 is further used to initialize the current inner loop link of the virtual synchronous control according to the output result of the droop control at the switching moment when the target meshing control mode is the virtual synchronous control mode, so as to switch from the droop control mode to the virtual synchronous control mode; when the target meshing control mode is the droop control mode, initialize the current inner loop link of the droop control according to the output result of the virtual synchronous control at the switching moment, and construct a ramp signal to switch from the virtual synchronous control mode to the droop control mode.

[0191] In one embodiment, the data control module 40 is further used to determine the inverter output power parameter according to the inverter grid-connected point output voltage measurement parameter and the inverter grid-connected point output current measurement parameter when the target grid-connected control mode is the virtual synchronous control mode; establish a virtual synchronous front-stage control equation based on the first droop coefficient parameter, the virtual moment of inertia, the virtual damping coefficient and the virtual synchronous machine rated parameter, and input the inverter output power parameter into the virtual synchronous front-stage control equation to obtain a reference voltage; establish a voltage outer loop and current inner loop control equation based on the voltage outer loop control coefficient, the current inner loop control coefficient and the reference voltage, and input the inverter outlet output current measurement parameter and the inverter grid-connected point output voltage measurement parameter into the voltage outer loop and current inner loop control equation to obtain the inverter output current reference parameter and the inverter output voltage reference parameter to determine the inverter control reference parameter.

[0192] In one embodiment, the data control module 40 is further used to determine the inverter output power parameter according to the inverter grid-connected point output voltage measurement parameter and the inverter grid-connected point output current measurement parameter when the target grid-connected control mode is the droop control mode; establish a droop front-stage control equation based on the second droop coefficient parameter, the virtual moment of inertia, the virtual damping coefficient and the virtual synchronous machine rated parameter, and input the grid-connected point angular velocity and the grid-connected point voltage into the droop front-stage control equation to obtain the reference active power and the reference active power; establish a power outer loop and current inner loop control equation based on the power outer loop control coefficient, the current inner loop control coefficient, the reference active power and the reference active power, and input the inverter grid-connected point output voltage measurement parameter, the inverter grid-connected point output current measurement parameter and the inverter output power parameter into the power outer loop and current inner loop control equation to obtain the inverter output current reference parameter and the inverter output voltage reference parameter to determine the inverter control reference parameter.

[0193] In one embodiment, the data control module 40 is further configured to deactivate the harmonic suppression strategy and activate the state of charge margin reservation strategy when the frequency deviation or the voltage deviation meets the harmonic suppression module removal condition; enhance the harmonic suppression weight of the multi-objective optimization function when the harmonic content and output current value corresponding to the grid harmonic spectrum meet the harmonic suppression enhancement condition; and return to the step of obtaining grid status data.

[0194] The multi-scenario collaborative control device for a grid-type energy storage converter provided in the present application adopts the multi-scenario collaborative control method for a grid-type energy storage converter in the above-mentioned embodiment, which can solve the technical problem of how to resolve the capacity conflict between grid-type control and harmonic control to perform multi-scenario collaborative control of a grid-type energy storage converter. Compared with the prior art, the beneficial effects of the multi-scenario collaborative control device for a grid-type energy storage converter provided in the present application are the same as the beneficial effects of the multi-scenario collaborative control method for a grid-type energy storage converter provided in the above-mentioned embodiment, and the other technical features in the multi-scenario collaborative control device for a grid-type energy storage converter are the same as the features disclosed in the above-mentioned embodiment method, which will not be repeated here.

[0195] The present application provides a multi-scenario collaborative control device for a grid-type energy storage converter, and the multi-scenario collaborative control device for a grid-type energy storage converter includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the multi-scenario collaborative control method for the grid-type energy storage converter in the above-mentioned embodiment one.

[0196] Reference below Figure 4 , which shows a structural diagram of a multi-scenario collaborative control device for a network-type energy storage converter suitable for implementing an embodiment of the present application. The multi-scenario collaborative control device for a network-type energy storage converter in the embodiment of the present application may include but is not limited to mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 4 The multi-scenario collaborative control device of the grid-type energy storage converter shown is merely an example and should not impose any limitations on the functions and scope of use of the embodiments of the present application.

[0197] like Figure 4As shown, the multi-scenario collaborative control device of the network-type energy storage converter may include a processing device 1001 (such as a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to the program stored in the ROM (Read Only Memory) 1002 or the program loaded from the storage device 1003 to the RAM (Random Access Memory) 1004. Various programs and data required for the operation of the multi-scenario collaborative control device of the network-type energy storage converter are also stored in RAM1004. The processing device 1001, ROM1002 and RAM1004 are connected to each other via a bus 1005. The input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 1006: an input device 1007 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; an output device 1008 including, for example, an LCD (Liquid Crystal Display), a speaker, a vibrator, etc.; a storage device 1003 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 can allow the multi-scenario collaborative control device of the network-type energy storage converter to communicate wirelessly or wired with other devices to exchange data. Although the figure shows a multi-scenario collaborative control device of the network-type energy storage converter with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems may be implemented or have instead.

[0198] In particular, according to the embodiments disclosed in the present application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, the embodiments disclosed in the present application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program comprising program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0199] The multi-scenario collaborative control device for a grid-type energy storage converter provided in the present application adopts the multi-scenario collaborative control method for a grid-type energy storage converter in the above-mentioned embodiment, which can solve the technical problem of how to resolve the capacity conflict between grid-type control and harmonic control to perform multi-scenario collaborative control of a grid-type energy storage converter. Compared with the prior art, the beneficial effects of the multi-scenario collaborative control device for a grid-type energy storage converter provided in the present application are the same as the beneficial effects of the multi-scenario collaborative control method for a grid-type energy storage converter provided in the above-mentioned embodiment, and the other technical features in the multi-scenario collaborative control device for a grid-type energy storage converter are the same as the features disclosed in the method of the previous embodiment, which will not be repeated here.

[0200] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0201] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0202] The present application provides a computer-readable storage medium having computer-readable program instructions (i.e., computer programs) stored thereon, and the computer-readable program instructions are used to execute the multi-scenario collaborative control method of the grid-type energy storage converter in the above-mentioned embodiment.

[0203] The computer-readable storage medium provided in this application can be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination thereof. More specific examples of computer-readable storage media can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, RAM (Random Access Memory), ROM (Read Only Memory), EPROM (Erasable Programmable Read Only Memory) or flash memory, optical fiber, CD-ROM (CD-Read Only Memory, portable compact disk read-only memory), optical storage device, magnetic storage device, or any suitable combination thereof. In this embodiment, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium can be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0204] The above-mentioned computer-readable storage medium can be included in the multi-scenario collaborative control device of the grid-type energy storage converter; or it can exist independently without being assembled into the multi-scenario collaborative control device of the grid-type energy storage converter.

[0205] The above-mentioned computer-readable storage medium carries one or more programs. When the above-mentioned one or more programs are executed by the multi-scenario collaborative control device of the grid-type energy storage converter, the multi-scenario collaborative control device of the grid-type energy storage converter: obtains grid status data, and determines the grid connection point power, grid frequency, grid voltage and grid harmonic spectrum based on the grid status data; establishes a multi-objective optimization function, energy storage system charge state constraints and converter output current constraints based on the grid connection point power, the grid frequency, the grid voltage and the grid harmonic spectrum; performs multi-objective optimization solution based on the multi-objective optimization function, the energy storage system charge state constraints and the converter output current constraints to obtain the fundamental current reference value and the harmonic current limit value; controls the output current of the grid-type energy storage converter based on the grid-type fundamental current reference value and the grid-type harmonic current limit value.

[0206] The computer program code for performing the operations of the present application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer can be connected to the user's computer through any type of network, including a LAN (Local Area Network) or a WAN (Wide Area Network), or can be connected to an external computer (e.g., using an Internet service provider to connect via the Internet).

[0207] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, program segment or a part of code, and the module, program segment or a part of code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0208] The modules described in the embodiments of the present application may be implemented in software or hardware, wherein the name of a module does not necessarily limit the unit itself.

[0209] The readable storage medium provided in this application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned grid-type energy storage converter multi-scenario collaborative control method, which can solve the technical problem of how to resolve the capacity conflict between grid-type control and harmonic governance to perform multi-scenario collaborative control of grid-type energy storage converters. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as the beneficial effects of the grid-type energy storage converter multi-scenario collaborative control method provided in the above-mentioned embodiment, and will not be elaborated here.

[0210] The present application also provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of the multi-scenario collaborative control method of the grid-type energy storage converter as described above.

[0211] The computer program product provided in this application can address the technical problem of resolving capacity conflicts between grid-type control and harmonic management to enable multi-scenario collaborative control of grid-type energy storage converters. Compared to the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the multi-scenario collaborative control method for grid-type energy storage converters provided in the above-mentioned embodiments, and are not further elaborated here.

[0212] The above description is only part of the embodiments of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made by using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A multi-scenario collaborative control method for a grid-type energy storage converter, characterized in that: The multi-scenario collaborative control method of the grid-type energy storage converter includes: Obtaining grid status data, and determining grid connection point power, grid frequency, grid voltage, and grid harmonic spectrum based on the grid status data; Establishing a multi-objective optimization function, energy storage system state of charge constraints, and converter output current constraints based on the grid connection point power, the grid frequency, the grid voltage, and the grid harmonic spectrum; Perform multi-objective optimization based on the multi-objective optimization function, the energy storage system state of charge constraint, and the converter output current constraint to obtain a fundamental current reference value and a harmonic current limit value; The output current of the grid-type energy storage converter is controlled based on the grid-type fundamental current reference value and the grid-type harmonic current limit value.

2. The method according to claim 1, wherein The step of establishing a multi-objective optimization function, energy storage system state of charge constraints, and converter output current constraints based on the grid connection point power, the grid frequency, the grid voltage, and the grid harmonic spectrum includes: Determining a grid connection point active power historical data sequence, a frequency deviation, a voltage deviation, an output current fundamental component amplitude, and an output current harmonic component amplitude based on the grid connection point power, grid frequency, grid voltage, and grid harmonic spectrum; Predicting grid power fluctuations based on the historical data sequence of active power at the grid connection point; Constructing a multi-objective optimization function based on the grid power fluctuation, the frequency deviation, the voltage deviation, and the amplitude of the output current fundamental component; Establishing the energy storage system's state of charge constraints based on the energy storage system's current state of charge, energy storage output power, rated capacity, and control period; A converter output current constraint is established according to the amplitude of the output current fundamental component and the amplitude of the output current harmonic component.

3. The method according to claim 1, wherein Before the step of controlling the output current of the grid-type energy storage converter based on the grid-type fundamental current reference value and the grid-type harmonic current limit value, the method further includes: Based on the grid status data, the transient voltage mutation sign parameter, transient frequency disturbance sign parameter, grid strength assessment parameter, frequency deviation duration parameter, and energy storage system charge state parameter are determined to obtain the grid-type control mode switching information; When the network-type control mode switching information meets the preset switching condition, determining the target network-type control mode to be the virtual synchronous control mode or the droop control mode; Based on the target grid-type control mode, inverter control reference parameters are determined according to inverter grid-connected point output voltage measurement parameters and inverter grid-connected point output current measurement parameters.

4. The method according to claim 3, wherein Before the step of determining the inverter control reference parameters based on the target grid-connected control mode according to the inverter grid-connected point output voltage measurement parameters and the inverter grid-connected point output current measurement parameters, the step includes: When the target network control mode is the virtual synchronous control mode, initializing the current inner loop of the virtual synchronous control according to the output result of the droop control at the switching moment, so as to switch from the droop control mode to the virtual synchronous control mode; When the target meshing control mode is the droop control mode, the current inner loop of the droop control is initialized according to the output result of the virtual synchronous control at the switching moment, and a ramp signal is constructed to switch from the virtual synchronous control mode to the droop control mode.

5. The method according to claim 3, wherein The step of determining the inverter control reference parameters based on the target grid-connected control mode and the inverter grid-connected point output voltage measurement parameters and the inverter grid-connected point output current measurement parameters includes: When the target grid-type control mode is the virtual synchronous control mode, determining the inverter output power parameter according to the inverter grid-connected point output voltage measurement parameter and the inverter grid-connected point output current measurement parameter; Establishing a virtual synchronous front-stage control equation based on a first droop coefficient parameter, a virtual moment of inertia, a virtual damping coefficient, and a virtual synchronous machine rated parameter, and inputting the inverter output power parameter into the virtual synchronous front-stage control equation to obtain a reference voltage; Based on the voltage outer loop control coefficient, the current inner loop control coefficient, and the reference voltage, the voltage outer loop and current inner loop control equations are established, and the inverter outlet output current measurement parameters and the inverter grid-connected point output voltage measurement parameters are input into the voltage outer loop and current inner loop control equations to obtain the inverter output current reference parameters and the inverter output voltage reference parameters to determine the inverter control reference parameters.

6. The method according to claim 3, wherein The step of determining the inverter control reference parameters based on the target grid-connected control mode and the inverter grid-connected point output voltage measurement parameters and the inverter grid-connected point output current measurement parameters includes: When the target grid-type control mode is the droop control mode, determining the inverter output power parameter according to the inverter grid-connected point output voltage measurement parameter and the inverter grid-connected point output current measurement parameter; A droop front-stage control equation is established based on the second droop coefficient parameter, the virtual moment of inertia, the virtual damping coefficient, and the virtual synchronous machine rated parameters, and the grid connection point angular velocity and the grid connection point voltage are input into the droop front-stage control equation to obtain a reference active power and a reference active power; Based on the power outer loop control coefficient, the current inner loop control coefficient, the reference active power and the reference active power, the power outer loop and current inner loop control equations are established, and the inverter grid-connected point output voltage measurement parameters, the inverter grid-connected point output current measurement parameters and the inverter output power parameters are input into the power outer loop and current inner loop control equations to obtain the inverter output current reference parameters and the inverter output voltage reference parameters to determine the inverter control reference parameters.

7. The method according to any one of claims 1 to 6, characterized in that After the step of controlling the output current of the grid-type energy storage converter based on the grid-type fundamental current reference value and the grid-type harmonic current limit value, the method further includes: When the frequency deviation or the voltage deviation meets the harmonic suppression module removal condition, deactivating the harmonic suppression strategy and activating the state of charge margin reservation strategy; When the harmonic content and output current value corresponding to the harmonic spectrum of the power grid meet the harmonic suppression improvement conditions, increasing the harmonic suppression weight of the multi-objective optimization function; Return to the step of obtaining grid status data.

8. A multi-scenario collaborative control device for a grid-type energy storage converter, characterized in that: The device comprises: A data acquisition module is used to acquire grid status data and determine the grid connection point power, grid frequency, grid voltage and grid harmonic spectrum based on the grid status data; A data processing module, configured to establish a multi-objective optimization function, an energy storage system state of charge constraint, and a converter output current constraint based on the grid connection point power, the grid frequency, the grid voltage, and the grid harmonic spectrum; A data output module is configured to perform a multi-objective optimization solution based on the multi-objective optimization function, the energy storage system state of charge constraint, and the converter output current constraint to obtain a fundamental current reference value and a harmonic current limit value; A data control module is used to control the output current of the grid-type energy storage converter based on the grid-type fundamental current reference value and the grid-type harmonic current limit value.

9. A multi-scenario collaborative control device for a grid-type energy storage converter, characterized in that: The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the multi-scenario collaborative control method for a grid-type energy storage converter as described in any one of claims 1 to 7.

10. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by the processor, the steps of the multi-scenario collaborative control method of the grid-type energy storage converter according to any one of claims 1 to 7 are implemented.

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