A control method, device and system of an energy storage system

Abstract

The application discloses a control method, device and system of an energy storage system, which is applied to a high-low rate energy storage system. The high-low rate energy storage system comprises a high rate energy storage subsystem and a low rate energy storage subsystem. The energy storage charge-discharge curve of a preset future time period is obtained by predicting the power grid side load curve and the power generation side power generation curve of the preset future time period. Different high-low rate control strategies are adopted for the high-low rate energy storage system to enter a charge-dominant scene or a discharge-dominant scene based on the energy storage charge-discharge curve. The high-low rate energy storage system provided by the application can provide different charge-discharge strategies under different charge-discharge scenes. The short-term peak load can be better coped with through the high rate energy storage subsystem, so that the cycle life of the battery is improved, and the service life of the energy storage system is prolonged.

Description

Technical Field

[0001] This invention relates to the field of energy storage system technology, and more specifically, to a control method, device and control system for an energy storage system. Background Technology

[0002] In energy storage systems, especially lithium iron phosphate (LFP) energy storage systems, battery cycle life is generally calculated based on a complete charge-discharge cycle. However, when the battery is not fully charged and discharged, its cycle life is calculated using cycles at different depths of discharge (DOD). In LFP energy storage systems, if the depth of discharge remains at a plateau, the estimation of the battery's state of charge (SOC) will be inaccurate, resulting in a larger error in the cycle life calculation factor. Battery manufacturers tend to increase the cycle life calculation factor as much as possible, thereby reducing the battery's usage time and ultimately decreasing the battery's cycle life, which in turn reduces the lifespan of the energy storage system. Summary of the Invention

[0003] In view of this, the present invention discloses a control method, device and control system for an energy storage system, so as to improve the cycle life of the battery and extend the service life of the energy storage system.

[0004] A control method for an energy storage system, applied to a high- and low-rate energy storage system, wherein the high- and low-rate energy storage system includes a high-rate energy storage subsystem and a low-rate energy storage subsystem, and the control method includes:

[0005] Predict the grid load curve and the generation curve of the generation side for a preset future time period;

[0006] Based on the grid-side load curve and the power generation curve, the energy storage charge and discharge curve of the high- and low-rate energy storage system is generated in the preset future time period.

[0007] Based on the relationship between the current state of charge of the low-rate energy storage subsystem and the minimum and maximum thresholds of the low-rate state of charge, it is determined whether the high-rate or low-rate energy storage system enters a scenario dominated by charging or discharging.

[0008] When the high- and low-rate energy storage system enters a scenario dominated by charging or discharging, the corresponding high- and low-rate control strategy is determined based on the energy storage charge-discharge curve.

[0009] Optionally, determining whether the high- or low-rate energy storage system enters a scenario primarily for charging or discharging based on the relationship between the current state of charge of the low-rate energy storage subsystem and the minimum and maximum thresholds of the low-rate state of charge includes:

[0010] When the current state of charge is not greater than the minimum threshold of the low-rate state of charge, the high-low rate energy storage system is determined to enter a charging-oriented scenario.

[0011] When the current state of charge is not less than the maximum threshold of the low-rate state of charge, the high- and low-rate energy storage system is determined to enter a scenario dominated by discharge.

[0012] Optionally, when the high- and low-rate energy storage system enters a scenario primarily focused on charging or discharging, determining the corresponding high- and low-rate control strategy based on the energy storage charge-discharge curve includes:

[0013] When the high- and low-rate energy storage system enters a scenario primarily focused on charging, a high- and low-rate control strategy for the energy storage system, primarily focused on charging, is adopted based on the energy storage charge-discharge curve. Specifically, this includes:

[0014] The high and low rate energy storage system is controlled primarily for charging, and the energy of the high and low rate energy storage system is combined with different time scales of the energy storage charge and discharge curve for charge and discharge control.

[0015] Optionally, the control of the high- and low-rate energy storage system is primarily based on charging, and the energy of the high- and low-rate energy storage system is combined with different time scales of the energy storage charge-discharge curve for charge-discharge control, including:

[0016] Obtain the high-rate energy to be charged from the high-rate energy storage subsystem and the low-rate energy to be charged from the low-rate energy storage subsystem;

[0017] The energy storage charge and discharge curves are divided into long time scales, medium time scales, and short time scales according to a preset division standard.

[0018] Determine the first charging energy corresponding to the long time scale, the second charging energy corresponding to the medium time scale, and the third charging energy corresponding to the short time scale;

[0019] When the high- and low-rate energy storage system is mainly charging, a first charging and discharging control strategy for the high-rate energy storage subsystem and the low-rate energy storage subsystem is determined based on the relationship between the first charging energy, the high-rate energy to be charged, and the low-rate energy to be charged.

[0020] The charging and discharging duration in the first charging and discharging control strategy is determined based on the relationship between the second charging energy and the third charging energy.

[0021] Optionally, the preset division criterion is: based on the sign of the charging / discharging current and the minimum time scale T. delta When nT deltaWhen the charging and discharging modes switch, the time scales are divided into high, medium and low according to the size of n.

[0022] If nT delta If there is no change in current direction, then n1 is represented as the long time-scale coefficient, n2 as the medium time-scale coefficient, and n3 as the low time-scale coefficient, where n1 > n2 > n3, to ensure that the minimum time interval is not lower than the minimum time-scale discrimination T. min ;

[0023] Correspondingly, n1T delta Representing the time scale, n2T delta Indicates the time scale, n3T delta This indicates the short time scale.

[0024] Optionally, when the high-rate and low-rate energy storage systems are primarily used for charging, a first charge-discharge control strategy is determined for the high-rate energy storage subsystem and the low-rate energy storage subsystem based on the relationship between the first charging energy, the high-rate energy to be charged, and the low-rate energy to be charged. This strategy includes:

[0025] Determine whether the first charging energy is greater than the sum of the high-rate charging energy and the low-rate charging energy;

[0026] If so, then, provided that the high-rate energy storage subsystem's power capacity meets the long-term discharge conditions, the high-rate energy storage subsystem is charged and discharged first, and then the low-rate energy storage subsystem is charged. The charging and discharging duration is based on the larger of the second charging energy and the third charging energy for charging the low-rate energy storage subsystem. Once the low-rate energy storage subsystem is fully charged, the high-rate energy storage subsystem is charged again, until the high-rate energy storage subsystem is fully charged.

[0027] Optionally, the first charge / discharge control strategy further includes:

[0028] If not, determine whether the first charging energy is greater than the low-rate charging energy;

[0029] If so, the low-rate energy storage subsystem is charged first, and the charging time is based on the greater of the second charging energy and the third charging energy for the low-rate energy storage subsystem. When the high-rate and low-rate energy storage systems have a discharge requirement, the high-rate energy storage subsystem is controlled to discharge. When the high-rate energy storage subsystem has a low power, the high-rate energy storage subsystem is charged first, and the low-rate energy storage subsystem is charged only after the discharge function of the high-rate energy storage subsystem is satisfied.

[0030] Optionally, the first charge / discharge control strategy further includes:

[0031] If the first charging energy is not greater than the low-rate charging energy, then determine whether the sum of the first charging energy and the high-rate charging energy is greater than the low-rate charging energy.

[0032] If so, the low-rate energy storage subsystem is charged first, and the charging time is based on the greater of the second charging energy and the third charging energy for charging the low-rate energy storage subsystem; when the high-rate and low-rate energy storage systems have a discharge demand, the high-rate energy storage subsystem is controlled to discharge; when the high-rate and low-rate energy storage systems do not have a discharge demand, the high-rate energy storage subsystem is controlled to charge the low-rate energy storage subsystem until the remaining energy in the high-rate energy storage subsystem is transferred to the low-rate energy storage subsystem.

[0033] Optionally, the first charge / discharge control strategy further includes:

[0034] If not, the high-rate energy storage subsystem is charged first, and the charging time is based on the larger of the second charging energy and the third charging energy for the high-rate energy storage subsystem. When the high-rate energy storage subsystem is fully charged, the low-rate energy storage subsystem is then charged.

[0035] Optionally, when the high- and low-rate energy storage system enters a scenario primarily focused on charging or discharging, determining the corresponding high- and low-rate control strategy based on the energy storage charge-discharge curve includes: when the high- and low-rate energy storage system enters a scenario primarily focused on discharging, adopting a high- and low-rate control strategy for the energy storage system primarily focused on discharging based on the energy storage charge-discharging curve, specifically including:

[0036] The high- and low-rate energy storage systems are controlled primarily for discharging, and the energy of the high- and low-rate energy storage systems is combined with different time scales of the energy storage charge-discharge curve for charge-discharge control, wherein the low-rate energy storage subsystem is primarily for discharging.

[0037] Optionally, the control of the high- and low-rate energy storage system to primarily discharge, and the combination of the energy of the high- and low-rate energy storage system with different time scales of the energy storage charge-discharge curve for charge-discharge control, includes:

[0038] Obtain the high-rate undischargeable energy of the high-rate energy storage subsystem and the low-rate undischargeable energy of the low-rate energy storage subsystem;

[0039] The energy storage charge and discharge curves are divided into long time scales, medium time scales, and short time scales according to a preset division standard.

[0040] Determine the first discharge energy corresponding to the long time scale, the second discharge energy corresponding to the medium time scale, and the third discharge energy corresponding to the short time scale;

[0041] When the high- and low-rate energy storage system is mainly discharging, a second charge-discharge control strategy for the high-rate energy storage subsystem and the low-rate energy storage subsystem is determined based on the relationship between the first discharge energy, the high-rate energy to be discharged, and the minimum value of the discharge-charge energy.

[0042] The charging and discharging duration in the second charging and discharging control strategy is determined based on the relationship between the second discharge energy and the third discharge energy.

[0043] Optionally, when the high-rate and low-rate energy storage systems are primarily discharging, a second charge-discharge control strategy is determined for the high-rate energy storage subsystem and the low-rate energy storage subsystem based on the relationship between the first discharge energy, the high-rate energy to be discharged, and the low-rate energy to be discharged, including:

[0044] Determine whether the first discharge energy is greater than the sum of the high-rate discharge energy and the low-rate discharge energy;

[0045] If so, the low-rate energy storage subsystem is controlled to discharge only, while the high-rate energy storage subsystem is controlled to charge and discharge independently. The charging and discharging duration is determined by the larger of the second discharge energy and the third discharge energy for the high-rate energy storage subsystem, until both the high-rate energy storage subsystem and the low-rate energy storage subsystem are depleted.

[0046] Optionally, the second charge / discharge control strategy further includes:

[0047] If not, determine whether the first discharge energy is greater than the low-rate discharge energy;

[0048] If so, the low-rate energy storage subsystem is discharged first, and the discharge duration is based on the larger of the second discharge energy and the third discharge energy for the low-rate energy storage subsystem to discharge. The high-rate energy storage subsystem is controlled to discharge. When the high-rate energy storage subsystem is about to be fully charged, the high-rate energy storage subsystem is discharged first to ensure that the low-rate energy storage subsystem only discharges.

[0049] Optionally, the second charge / discharge control strategy further includes:

[0050] When the first discharge energy is not greater than the low-rate discharge energy, determine whether the sum of the first discharge energy and the high-rate discharge energy is greater than the low-rate discharge energy.

[0051] If so, the low-rate energy storage subsystem is discharged first, and the discharge duration is determined by the larger of the second discharge energy and the third discharge energy for the low-rate energy storage subsystem to discharge; when the high- and low-rate energy storage systems have a charging demand, the high-rate energy storage subsystem is charged; when the high- and low-rate energy storage systems do not have a charging demand, the low-rate energy storage subsystem is controlled to discharge to the high-rate energy storage subsystem.

[0052] Optionally, the second charge / discharge control strategy further includes:

[0053] If not, the high-rate energy storage subsystem is discharged first, and the charging and discharging time is the larger of the second discharge energy and the third discharge energy for the high-rate energy storage subsystem. When the high-rate energy storage subsystem is emptied, the low-rate energy storage subsystem is then discharged.

[0054] A control device for an energy storage system, applied to a high-rate and low-rate energy storage system, the high-rate and low-rate energy storage system comprising: a high-rate energy storage subsystem and a low-rate energy storage subsystem, the control device comprising:

[0055] The curve prediction unit is used to predict the grid-side load curve and the generation curve of the generation side for a preset future time period.

[0056] The curve generation unit is used to generate the energy storage charge and discharge curve of the high- and low-rate energy storage system in the preset future time period based on the grid-side load curve and the generation-side power generation curve.

[0057] The charging and discharging scenario determination unit is used to determine whether the high- and low-rate energy storage system enters a scenario dominated by charging or a scenario dominated by discharging, based on the relationship between the current state of charge of the low-rate energy storage subsystem and the minimum threshold and maximum threshold of the low-rate state of charge.

[0058] The control unit is used to determine the corresponding high- or low-rate control strategy based on the energy storage charge-discharge curve when the high- or low-rate energy storage system enters a scenario dominated by charging or discharging.

[0059] An energy storage system includes: the control device described above.

[0060] As can be seen from the above technical solution, this invention discloses a control method, device, and control system for an energy storage system, applied to high- and low-rate energy storage systems. The high- and low-rate energy storage system includes a high-rate energy storage subsystem and a low-rate energy storage subsystem. By predicting the grid-side load curve and the generation curve of the generator side for a preset future time period, the energy storage charge-discharge curve for that preset future time period is obtained. Based on this energy storage charge-discharge curve, different high- and low-rate control strategies are adopted for scenarios where the high- and low-rate energy storage system is primarily engaged in charging or discharging. The high- and low-rate energy storage system proposed in this invention can provide different charge-discharge strategies under different charging and discharging scenarios. The high-rate energy storage subsystem can better cope with short-term peak loads, thereby improving the battery cycle life and extending the service life of the energy storage system. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the published drawings without creative effort.

[0062] Figure 1 This is a topology diagram of a high- and low-rate energy storage system disclosed in an embodiment of the present invention;

[0063] Figure 2 This is a flowchart of a control method for an energy storage system disclosed in an embodiment of the present invention;

[0064] Figure 3 This is a flowchart of a method for controlling the charging and discharging of a high- and low-rate energy storage system, which is mainly based on charging, by combining the energy of the high- and low-rate energy storage system with different time scales of the energy storage charging and discharging curve.

[0065] Figure 4 This is a flowchart of a method for controlling a high-rate energy storage subsystem and a low-rate energy storage subsystem according to a first charge-discharge control strategy, as disclosed in an embodiment of the present invention.

[0066] Figure 5 This is a flowchart of a method for controlling the charge and discharge of a high- and low-rate energy storage system, which is mainly based on discharge, by combining the energy of the high- and low-rate energy storage system with different time scales of the energy storage charge and discharge curve.

[0067] Figure 6 This is a flowchart of a method for controlling a high-rate energy storage subsystem and a low-rate energy storage subsystem according to a second charge-discharge control strategy, as disclosed in an embodiment of the present invention.

[0068] Figure 7This is a schematic diagram of the structure of a control device for an energy storage system disclosed in an embodiment of the present invention. Detailed Implementation

[0069] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0070] This invention discloses a control method, device, and control system for an energy storage system, applicable to high- and low-rate energy storage systems. The high- and low-rate energy storage system includes a high-rate energy storage subsystem and a low-rate energy storage subsystem. By predicting the grid-side load curve and the generation curve of the generator side for a preset future time period, the energy storage charge-discharge curve for that preset future time period is obtained. Based on this energy storage charge-discharge curve, different high- and low-rate control strategies are adopted for scenarios where the high- and low-rate energy storage system is primarily engaged in charging or discharging. The high- and low-rate energy storage system proposed in this invention can provide different charge-discharge strategies under different charging and discharging scenarios. The high-rate energy storage subsystem can better cope with short-term peak loads, thereby improving the battery cycle life and extending the service life of the energy storage system.

[0071] To improve battery cycle life and energy storage system lifespan, this invention improves the architecture of traditional energy storage systems. See also... Figure 1 The present invention discloses a topology diagram of a high-low rate energy storage system. The energy storage system consists of a high-rate energy storage subsystem 11 and a low-rate energy storage subsystem 12. That is, the energy storage system in the present invention adopts different combinations of charge and discharge rates. Compared with the traditional single-rate energy storage system, the energy storage system in the present invention is a high-low rate energy storage system, and the high-low rate energy storage system is connected to the grid GRID.

[0072] If the overall energy storage system ratio is A, and the α part is selected as the high-ratio energy storage subsystem 11, then Scheme B is used, where α∈(0, x], and the value of x is selected according to the peak application scenario of the energy storage system. This invention does not limit the value of x.

[0073] When using Option B for energy storage to meet peak energy demand, in this embodiment, to avoid the impact of battery aging on energy storage, the preferred value of x is 20% to 50%.

[0074] It should be noted that, due to the different batteries in high-rate energy storage subsystems, the safety and device requirements for the entire energy storage system are higher.

[0075] In actual operation, the high- and low-rate energy storage system disclosed in this invention, in order to cope with the dynamic changes on the grid side and the generation side, predicts the load and power generation for a preset future time period. Based on the prediction results, it determines the specific dynamic adjustment scheme for the high- and low-rate charging and discharging of the energy storage system, so that the low-rate energy storage subsystem can achieve the deepest DOD (Dead-of-Device) as possible, which can extend the service life of the low-rate energy storage subsystem and better predict its cycle life. The specific control logic is as follows:

[0076] See Figure 2 The present invention discloses a flowchart of a control method for an energy storage system, which is applied to... Figure 1 The high- and low-rate energy storage system shown in the embodiment includes a control method comprising:

[0077] Step S101: Predict the grid-side load curve and the generation curve of the generation side for a preset future time period;

[0078] In practical applications, historical grid load curves and historical generator generation curves can be combined with machine learning and other methods to predict grid load curves and generator generation curves for a preset future time period. For specific prediction processes, please refer to existing machine learning methods. This invention does not limit these methods.

[0079] The value of the preset future time period is determined according to actual needs, and this invention does not limit it.

[0080] Step S102: Based on the grid-side load curve and the generator-side generation curve, generate the energy storage charge and discharge curves of the high and low rate energy storage system in a preset future time period;

[0081] Step S103: Based on the relationship between the current state of charge of the low-rate energy storage subsystem and the minimum threshold and maximum threshold of the low-rate state of charge, determine whether the high-rate or low-rate energy storage system enters a scenario dominated by charging or discharging.

[0082] Specifically, assume the current state of charge (SOC) of the low-rate energy storage subsystem is... LP The minimum state of charge (SOC) threshold for low-rate energy storage subsystems, also known as the minimum SOC threshold for low-rate energy storage subsystems, is... LP_thmin The maximum state of charge (SOC) threshold for low-rate energy storage subsystems, also known as the maximum SOC threshold for low-rate energy storage subsystems. LP_thmax .

[0083] (1) When the current state of charge is not greater than the minimum threshold of the low-rate state of charge, the high- and low-rate energy storage system is determined to enter the charging-oriented scenario.

[0084] In practical applications, when SOC LP ≤SOCLP_thmin At that time, an appropriate long-term time scale should be selected to ensure that the energy storage system is mainly used for charging.

[0085] (2) When the current state of charge is not less than the maximum threshold of the low-rate state of charge, the high- and low-rate energy storage systems are determined to enter a scenario dominated by discharge.

[0086] In practical applications, when SOC LP ≥SOC LP_thmax At that time, a suitable long-term time scale should be selected to ensure that the energy storage system is mainly used for discharge.

[0087] (3) When the current state of charge is between the minimum threshold of the low-rate state of charge and the maximum threshold of the low-rate state of charge, the original charging and discharging logic is maintained.

[0088] In other words, when SOC LP_thmin <SOC LP <SOC LP_thmax At the same time, maintain the original charging and discharging logic.

[0089] Step S104: When the high- and low-rate energy storage system enters a scenario dominated by charging or discharging, the corresponding high- and low-rate control strategy is determined based on the energy storage charge-discharge curve.

[0090] It should be noted that different high- and low-rate control strategies are adopted when the high- and low-rate energy storage systems enter scenarios that are mainly for charging or discharging.

[0091] In summary, this invention discloses a control method for an energy storage system, applicable to high- and low-rate energy storage systems. The high- and low-rate energy storage system includes a high-rate energy storage subsystem and a low-rate energy storage subsystem. By predicting the grid-side load curve and the generation curve of the generator side for a preset future time period, the energy storage charge-discharge curve for that preset future time period is obtained. Based on this energy storage charge-discharge curve, different high- and low-rate control strategies are adopted for scenarios where the high- and low-rate energy storage system is primarily engaged in charging or discharging. The high- and low-rate energy storage system proposed in this invention can provide different charge-discharge strategies under different charging and discharging scenarios. The high-rate energy storage subsystem can better cope with short-term peak loads, thereby improving the battery cycle life and extending the service life of the energy storage system.

[0092] To further optimize the above embodiments, step S104 may specifically include:

[0093] When the high- and low-rate energy storage system enters a scenario dominated by charging or discharging, the corresponding high- and low-rate control strategy is determined based on the energy storage charge-discharge curve.

[0094] In practical applications, when high- and low-rate energy storage systems enter a scenario where charging is the primary function, the high-rate energy storage system is controlled to primarily charge, and the energy of the high- and low-rate energy storage systems is combined with different time scales of the energy storage charge-discharge curves for charge-discharge control.

[0095] To further optimize the above embodiments, see [link to relevant documentation]. Figure 3 The present invention discloses a method for controlling the charge and discharge of a high- and low-rate energy storage system, primarily based on charging, by combining the energy of the high- and low-rate energy storage system with different time scales of the energy storage charge and discharge curve. The method includes:

[0096] Step S201: Obtain the high-rate energy to be charged from the high-rate energy storage subsystem and the low-rate energy to be charged from the low-rate energy storage subsystem;

[0097] In this embodiment, the energy to be charged refers to the charging energy required for the system to go from its current SOC to a fully charged state.

[0098] In this embodiment, the high-rate energy to be charged refers to the charging energy required for the high-rate energy storage subsystem to go from its current SOC to a fully charged state.

[0099] Low-rate energy to be charged refers to the charging energy required for a low-rate energy storage subsystem to go from its current SOC to a fully charged state.

[0100] For ease of subsequent discussion, the energy to be charged at a high rate can be expressed as E_chrg. hi The energy available for charging at a low rate can be expressed as E_chrg lw .

[0101] Step S202: Divide the energy storage charge and discharge curves into long time scales, medium time scales, and short time scales according to the preset division criteria;

[0102] The preset division criteria are: based on the sign of the charging and discharging current and the minimum time scale T. delta When nT delta When the charging and discharging modes switch, the time scales are divided into high, medium and low according to the size of n.

[0103] If nT delta If there is no change in current direction, such as continuous charging, then n1 is represented as the long time-scale coefficient, n2 as the medium time-scale coefficient, and n3 as the low time-scale coefficient, where n1 > n2 > n3, to ensure that the minimum time interval is not less than the minimum time-scale discrimination T. min .

[0104] Correspondingly, n1T delta Representing a long time scale, n²T delta Representing the medium time scale, n3Tdelta It indicates a short time scale.

[0105] Step S203: Determine the first charging energy corresponding to the long time scale, the second charging energy corresponding to the medium time scale, and the third charging energy corresponding to the short time scale.

[0106] In practical applications, the first charging energy corresponding to a long time scale can be expressed as E. l The second charging energy corresponding to the medium time scale can be expressed as E n The third charging energy corresponding to a short timescale can be expressed as E. s .

[0107] It should be noted that since the energy storage charge-discharge curve is the charge-discharge curve of the energy storage system over a predetermined future time period, the long-term, medium-term, and short-term time scales obtained from the energy storage charge-discharge curve are also predetermined future time periods. Correspondingly, the first charging energy E l Second charging energy E n And the third charging energy E s These represent the energy storage and charging capacity for different time periods in the future.

[0108] Step S204: When the high-rate and low-rate energy storage system is mainly charging, a first charge-discharge control strategy for the high-rate energy storage subsystem and the low-rate energy storage subsystem is determined based on the relationship between the first charging energy and the high-rate energy to be charged and the low-rate energy to be charged.

[0109] In the first charge-discharge control strategy, the charge-discharge duration is determined based on the relationship between the second charging energy and the third charging energy.

[0110] For ease of understanding, see [link to relevant documentation]. Figure 4 The present invention discloses a method for controlling a high-rate energy storage subsystem and a low-rate energy storage subsystem according to a first charge-discharge control strategy, the method comprising:

[0111] Step S301: Determine whether the first charging energy is greater than the sum of the high-rate charging energy and the low-rate charging energy. If yes, proceed to step S302; otherwise, proceed to step S303.

[0112] Specifically, when E l >E_chrg hi +E_chrg lwUpon establishment, it is stated that all high- and low-rate energy storage systems can be fully charged over a long timescale. At this point, the system first ensures that the high-rate energy storage subsystem meets the discharge requirements of each short timescale over the long timescale, charging the high-rate subsystem before charging the low-rate subsystem. When either the high- or low-rate energy storage system has a discharge requirement, the high-rate subsystem discharges independently. When the low-rate energy storage subsystem is fully charged, the high-rate subsystem is then charged. This process is detailed in the first control sub-strategy in step S302.

[0113] Conversely, when E l >E_chrg hi +E_chrg lw If the condition is not met, it means that not all high- and low-rate energy storage systems can be fully filled over a long time scale. In this case, proceed to step S303.

[0114] Among them, E l E_chrg represents the first charging energy. hi E_chrg represents the energy to be charged at a high rate. lw This indicates the energy available for charging at a low rate.

[0115] Step S302: Execute the first control sub-policy;

[0116] The first control sub-strategy is as follows: under the condition that the high-rate energy storage subsystem meets the discharge conditions on a long time scale, the high-rate energy storage subsystem is charged and discharged first, and then the low-rate energy storage subsystem is charged. The charging and discharging time is based on the larger of the second charging energy and the third charging energy for charging the low-rate energy storage subsystem. When the low-rate energy storage subsystem is fully charged, the high-rate energy storage subsystem is charged again, until the high-rate energy storage subsystem is fully charged.

[0117] Step S303: Determine whether the first charging energy is greater than the low-rate charging energy. If yes, proceed to step S304; otherwise, proceed to step S305.

[0118] Specifically, when E l >E_chrg lw When established, it indicates that the low-rate energy storage subsystem can be fully charged over a long time scale. At this point, the charging time period of the low-rate energy storage subsystem can be determined by medium and short time scales. While satisfying the discharge function of the high-rate energy storage subsystem, the low-rate energy storage subsystem is charged until it is fully charged. This process is detailed in the second control sub-strategy.

[0119] When E l >E_chrg lw If the condition is not met, it means that the low-rate energy storage subsystem cannot be fully charged over a long time scale, and step S305 is executed.

[0120] Step S304: Execute the second control sub-policy;

[0121] The second control sub-strategy is as follows: prioritize charging the low-rate energy storage subsystem, and charge the low-rate energy storage subsystem for the greater of the second charging energy and the third charging energy; when the high-rate and low-rate energy storage systems have a discharge demand, control the high-rate energy storage subsystem to discharge; when the high-rate energy storage subsystem has a low power, prioritize charging the high-rate energy storage subsystem, and then charge the low-rate energy storage subsystem only after satisfying the discharge function of the high-rate energy storage subsystem.

[0122] Step S305: Determine whether the sum of the first charging energy and the high-rate charging energy is greater than the low-rate charging energy. If yes, proceed to step S306; otherwise, proceed to step S307.

[0123] Specifically, when E l +E_chrg hi >E_chrg lw When established, it is explained that over a long timescale, the energy transfer from the high-rate energy storage subsystem can be increased to fully charge the low-rate energy storage subsystem. In this case, while ensuring the high-rate discharge demand over a long timescale, the high-rate energy storage subsystem is charged first. Once the discharge demand is met and the high-rate energy storage subsystem is fully charged, the low-rate energy storage subsystem is charged. Finally, the remaining energy from the high-rate energy storage subsystem is transferred to the low-rate energy storage system. This process is detailed in the third control sub-strategy.

[0124] When E l +E_chrg hi >E_chrg lw If the condition is not met, it means that the low-rate energy storage subsystem cannot be fully charged by increasing the energy of the high-rate energy storage subsystem over a long time scale. In this case, step S307 is executed.

[0125] Step S306: Execute the third control sub-policy;

[0126] The third control sub-strategy is as follows: prioritize charging the low-rate energy storage subsystem, and charge the low-rate energy storage subsystem for the greater of the second charging energy and the third charging energy; when the high-rate and low-rate energy storage systems have a discharge demand, control the high-rate energy storage subsystem to discharge; when the high-rate and low-rate energy storage systems do not have a discharge demand, control the high-rate energy storage subsystem to charge the low-rate energy storage subsystem until the remaining energy in the high-rate energy storage subsystem is transferred to the low-rate energy storage subsystem.

[0127] Step S307: Execute the fourth control sub-policy.

[0128] The fourth control sub-strategy is as follows: prioritize charging the high-rate energy storage subsystem, and charge the high-rate energy storage subsystem for the greater of the second charging energy and the third charging energy for the charging duration. When the high-rate energy storage subsystem is fully charged, then charge the low-rate energy storage subsystem.

[0129] To further optimize the above embodiments, step S104 may specifically include:

[0130] When the high- and low-rate energy storage system enters a scenario dominated by charging or discharging, the corresponding high- and low-rate control strategy is determined based on the energy storage charge-discharge curve.

[0131] In practical applications, when high- and low-rate energy storage systems enter a scenario where discharge is the primary function, the energy of the high- and low-rate energy storage systems is controlled by combining the energy of the high- and low-rate energy storage systems with different time scales of the energy storage charge-discharge curves. Among them, the low-rate energy storage subsystem is mainly used for discharge.

[0132] To further optimize the above embodiments, see [link to relevant documentation]. Figure 5 The present invention discloses a method for controlling the charge and discharge of a high- and low-rate energy storage system, which is primarily based on discharge, by combining the energy of the high- and low-rate energy storage system with different time scales of the energy storage charge and discharge curve. The method includes:

[0133] Step S401: Obtain the high-rate undischargeable energy of the high-rate energy storage subsystem and the low-rate undischargeable energy of the low-rate energy storage subsystem;

[0134] In this embodiment, the energy to be discharged refers to the discharge energy that can be provided from the current SOS state to the fully discharged state.

[0135] In this embodiment, the high-rate discharge energy refers to the discharge energy that the high-rate energy storage subsystem can provide from its current SOC to a fully discharged state.

[0136] Low-rate standby energy refers to the discharge energy that a low-rate energy storage subsystem can provide from its current SOC to a fully charged state.

[0137] For ease of subsequent discussion, the high-rate discharge energy can be expressed as E_dchrg hi The low-rate discharge energy can be expressed as E_dchrg lw .

[0138] Step S402: Divide the energy storage charge and discharge curves into long time scales, medium time scales, and short time scales according to preset division standards;

[0139] The preset division criteria are: based on the sign of the charging and discharging current and the minimum time scale T. delta When nT delta When the charging and discharging modes switch, the time scales are divided into high, medium and low according to the size of n.

[0140] If nT delta If there is no change in current direction, such as continuous charging, then n1 is represented as the long time-scale coefficient, n2 as the medium time-scale coefficient, and n3 as the low time-scale coefficient, where n1 > n2 > n3, to ensure that the minimum time interval is not less than the minimum time-scale discrimination T. min .

[0141] Correspondingly, n1T delta Representing a long time scale, n²T delta Representing the medium time scale, n3T delta It indicates a short time scale.

[0142] Step S403: Determine the first discharge energy corresponding to the long time scale, the second discharge energy corresponding to the medium time scale, and the third discharge energy corresponding to the short time scale.

[0143] In practical applications, the first charging energy corresponding to a long time scale can be expressed as E. l The second charging energy corresponding to the medium time scale can be expressed as E n The third charging energy corresponding to a short timescale can be expressed as E. s .

[0144] It should be noted that the working principle of steps S402 and S403 in this embodiment is the same as that of... Figure 3 Steps S202 and S203 in the illustrated embodiment are the same.

[0145] Step S404: When the high-rate and low-rate energy storage systems are mainly discharging, a second charge-discharge control strategy for the high-rate and low-rate energy storage subsystems is determined based on the relationship between the first discharge energy, the high-rate energy to be discharged, and the minimum value of the charge-discharge energy.

[0146] In the second charge-discharge control strategy, the charge-discharge duration is determined based on the relationship between the second discharge energy and the third discharge energy.

[0147] For ease of understanding, see [link to relevant documentation]. Figure 6 The present invention discloses a method for controlling a high-rate energy storage subsystem and a low-rate energy storage subsystem according to a second charge-discharge control strategy, the method comprising:

[0148] Step S501: Determine whether the first discharge energy is greater than the sum of the high-rate discharge energy and the low-rate discharge energy. If yes, proceed to step S502; otherwise, proceed to step S503.

[0149] Specifically, when E l >E_dchrg hi +E_dchrg lw When established, it indicates that the energy storage system can provide the maximum discharge energy over a long timescale. In this case, priority is given to discharging the high-rate energy storage subsystem to meet charging demands over medium- to short-term timescales, ensuring high energy utilization. This is achieved when the State of Charge (SOC) is met. HP When the SOC is less than SOCHP_thmin, the low-rate energy storage subsystem is discharged, where SOC HP For high-rate energy storage subsystems, SOC HP_thmin This is the lower discharge limit for the high-rate energy storage subsystem. When the low-rate energy storage subsystem is depleted, the high-rate energy storage subsystem is then depleted as well. This process is detailed in the fifth control strategy in step S502.

[0150] When E l >E_dchrg hi +E_dchrg lw If the condition is not met, it indicates that the energy storage system cannot provide the maximum discharge energy over a long time scale. In this case, proceed to step S503.

[0151] Step S502: Execute the fifth control sub-policy;

[0152] The fifth control sub-strategy is as follows: control the low-rate energy storage subsystem to only discharge, control the high-rate energy storage subsystem to charge and discharge independently, and the charging and discharging duration is based on the larger of the second discharge energy and the third discharge energy for the high-rate energy storage subsystem to charge and discharge until the high-rate energy storage subsystem and the low-rate energy storage subsystem are emptied.

[0153] Step S503: Determine whether the first discharge energy is greater than the low-rate discharge energy. If yes, proceed to step S504; otherwise, proceed to step S505.

[0154] Specifically, when E l >E_dchrg lw When established, it indicates that the low-rate energy storage subsystem can be emptied over a long time scale. At this time, the discharge time period of the low-rate energy storage subsystem can be determined by medium and short time scales. While satisfying the charging function of the high-rate energy storage subsystem in medium and short time scales, the low-rate energy storage subsystem is discharged until it is emptied.

[0155] When El >E_dchrg lw If the condition is not met, it means that it is not possible to vent the low-rate energy storage subsystem over a long time scale. In this case, step S505 is executed.

[0156] Step S504: Execute the sixth control sub-policy;

[0157] The sixth control sub-strategy is as follows: prioritize discharging the low-rate energy storage subsystem, and use the larger of the second and third discharge energies for the discharge of the low-rate energy storage subsystem. Control the charging and discharging of the high-rate energy storage subsystem. When the high-rate energy storage subsystem is about to be fully charged, prioritize the discharge of the high-rate energy storage subsystem to ensure that the low-rate energy storage subsystem only discharges.

[0158] Step S505: Determine whether the sum of the first discharge energy and the high-rate discharge energy is greater than the low-rate discharge energy. If yes, proceed to step S506; if no, proceed to step S507.

[0159] Specifically, when E l +E_chrg hi >E_chrg lw Upon establishment, it is explained that over a long timescale, the energy transfer from the high-rate energy storage subsystem can satisfy the depletion needs of the low-rate energy storage subsystem. In this case, while ensuring the charging requirements of the high-rate energy storage subsystem over a long timescale, priority is given to discharging the high-rate energy storage subsystem. When both the high-rate and low-rate energy storage systems meet their discharge requirements and the high-rate energy storage subsystem is fully charged, the low-rate energy storage subsystem is then discharged, ultimately transferring the remaining energy from the low-rate energy storage subsystem to the high-rate energy storage subsystem. This process is detailed in the seventh control sub-strategy of step S507.

[0160] When E l +E_chrg hi >E_chrg lw If the condition is not met, it means that over a long time scale, the energy transfer of the high-rate energy storage subsystem cannot satisfy the venting of the low-rate energy storage subsystem. In this case, step S507 is executed.

[0161] Step S507: Execute the seventh control sub-policy.

[0162] The seventh control sub-strategy is as follows: prioritize discharging the low-rate energy storage subsystem, and the discharge duration is determined by the larger of the second discharge energy and the third discharge energy for discharging the low-rate energy storage subsystem; when the high- and low-rate energy storage systems have a charging demand, charge the high-rate energy storage subsystem; when the high- and low-rate energy storage systems have no charging demand, control the low-rate energy storage subsystem to discharge to the high-rate energy storage subsystem.

[0163] Step S507: Execute the eighth control sub-policy.

[0164] The eighth control sub-strategy is as follows: the high-rate energy storage subsystem is discharged first, and the charging and discharging time is based on the larger of the second discharge energy and the third discharge energy for the high-rate energy storage subsystem. When the high-rate energy storage subsystem is emptied, the low-rate energy storage subsystem is then discharged.

[0165] It should be noted that the high- and low-rate energy storage system in this invention has a high accuracy in estimating SOH (State of Health, the battery's ability to store charge) when using different rate schemes. In fact, it transfers the complex and variable environment to the high-rate energy storage subsystem. When energy is transferred between the high-rate and low-rate energy storage subsystems, the SOH of the high-rate system is corrected through energy changes, so that the SOH estimate of the entire energy storage system is improved compared to the single-rate scheme. When the SOH of the high-rate scheme is low, only part of the battery pack of the high-rate scheme can be replaced, which is more advantageous for long-term maintenance.

[0166] In addition, the present invention has the following technical advantages:

[0167] (1) By combining high and low rate energy storage systems, it is possible to more intelligently respond to the charging and discharging strategies of high and low rate energy storage systems under different application scenarios, solve the problem of short-term charging and discharging of single rate schemes during short-term peak shaving and valley filling, and maximize the utilization of battery cycle life.

[0168] (2) By using different rate schemes, the low rate scheme can operate in the better working range and extend the service life of the low rate energy storage subsystem. When dealing with various fluctuations, the high rate scheme has more cycles than the low rate scheme, so the high rate scheme can be maintained and updated separately, reducing the need for dimensional updates of the low rate subsystem.

[0169] (3) Through the energy transfer process of high and low rate, the SOC of the high-rate energy storage subsystem and the SOC of the low-rate energy storage subsystem can be calibrated at the same time.

[0170] Corresponding to the above method embodiments, the present invention also discloses a control device for an energy storage system.

[0171] See Figure 7 The present invention discloses a schematic diagram of a control device for an energy storage system, which is applied to... Figure 1 The high- and low-rate energy storage system shown in the embodiment includes a control device comprising:

[0172] The curve prediction unit 601 is used to predict the grid-side load curve and the generation curve of the generation side for a preset future time period.

[0173] In practical applications, historical grid load curves and historical generator generation curves can be combined with machine learning and other methods to predict grid load curves and generator generation curves for a preset future time period. For specific prediction processes, please refer to existing machine learning methods. This invention does not limit these methods.

[0174] The value of the preset future time period is determined according to actual needs, and this invention does not limit it.

[0175] The curve generation unit 602 is used to generate the energy storage charge and discharge curve of the high- and low-rate energy storage system in the preset future time period based on the grid-side load curve and the power generation curve.

[0176] The charging and discharging scenario determination unit 603 is used to determine whether the high- and low-rate energy storage system enters a scenario dominated by charging or a scenario dominated by discharging based on the relationship between the current state of charge of the low-rate energy storage subsystem and the minimum threshold and maximum threshold of the low-rate state of charge.

[0177] The control unit 604 is used to determine the corresponding high-low rate control strategy based on the energy storage charge-discharge curve when the high-low rate energy storage system enters a scenario dominated by charging or a scenario dominated by discharging.

[0178] In practical applications, when high- and low-rate energy storage systems enter a scenario where charging is the primary function, the energy storage system focuses on charging, and the energy of the high- and low-rate energy storage systems is combined with different time scales of the energy storage charge and discharge curves for charge and discharge control.

[0179] When high- and low-rate energy storage systems enter a scenario where discharge is the primary function, the energy storage system primarily operates on the discharge side. The energy of the high- and low-rate energy storage systems is combined with different time scales of the energy storage charge-discharge curves for charge-discharge control. Among these, the low-rate energy storage subsystem primarily operates on the discharge side.

[0180] In summary, this invention discloses a control device for an energy storage system, applied to high- and low-rate energy storage systems. The high- and low-rate energy storage system includes a high-rate energy storage subsystem and a low-rate energy storage subsystem. By predicting the grid-side load curve and the generation curve of the generator side for a preset future time period, the energy storage charge-discharge curve for that preset future time period is obtained. Based on this energy storage charge-discharge curve, different high- and low-rate control strategies are adopted for scenarios where the high- and low-rate energy storage system is primarily engaged in charging or discharging. The high- and low-rate energy storage system proposed in this invention can provide different charge-discharge strategies under different charging and discharging scenarios. The high-rate energy storage subsystem can better cope with short-term peak loads, thereby improving the battery cycle life and extending the service life of the energy storage system.

[0181] To further optimize the above embodiments, the charging / discharging scenario determination unit 603 is specifically used for:

[0182] When the current state of charge is not greater than the minimum threshold of the low-rate state of charge, the high-low rate energy storage system is determined to enter a charging-oriented scenario.

[0183] When the current state of charge is not less than the maximum threshold of the low-rate state of charge, the high- and low-rate energy storage system is determined to enter a scenario dominated by discharge.

[0184] To further optimize the above embodiments, the control unit 604 is specifically used for:

[0185] The high and low rate energy storage system is controlled primarily for charging, and the energy of the high and low rate energy storage system is combined with different time scales of the energy storage charge and discharge curve for charge and discharge control.

[0186] The control unit 604 may specifically include:

[0187] The first acquisition subunit is used to acquire the high-rate energy to be charged of the high-rate energy storage subsystem and the low-rate energy to be charged of the low-rate energy storage subsystem.

[0188] The first division subunit is used to divide the energy storage charge-discharge curve into long time scale, medium time scale and short time scale according to a preset division standard.

[0189] The first charging energy determination subunit is used to determine the first charging energy corresponding to the long time scale, the second charging energy corresponding to the medium time scale, and the third charging energy corresponding to the short time scale.

[0190] The first control strategy determination subunit is used to determine the first charge and discharge control strategy for the high-rate energy storage subsystem and the low-rate energy storage subsystem based on the relationship between the first charging energy, the high-rate energy to be charged, and the low-rate energy to be charged when the high-rate and low-rate energy storage systems are mainly charging.

[0191] The charging and discharging duration in the first charging and discharging control strategy is determined based on the relationship between the second charging energy and the third charging energy.

[0192] The preset division criterion mentioned in this embodiment is: based on the sign of the charging and discharging current and the minimum time scale T. delta When nT delta When the charging and discharging modes switch, the time scales are divided into high, medium and low according to the size of n.

[0193] If nT deltaIf there is no change in current direction, then n1 is represented as the long time-scale coefficient, n2 as the medium time-scale coefficient, and n3 as the low time-scale coefficient, where n1 > n2 > n3, to ensure that the minimum time interval is not lower than the minimum time-scale discrimination T. min ;

[0194] Correspondingly, n1T delta Representing the time scale, n2T delta Indicates the time scale, n3T delta This indicates the short time scale.

[0195] To further optimize the above embodiments, the first control strategy determines that the subunit is specifically used for:

[0196] Determine whether the first charging energy is greater than the sum of the high-rate charging energy and the low-rate charging energy;

[0197] If so, then, provided that the high-rate energy storage subsystem's power capacity meets the long-term discharge conditions, the high-rate energy storage subsystem is charged and discharged first, and then the low-rate energy storage subsystem is charged. The charging and discharging duration is based on the larger of the second charging energy and the third charging energy for charging the low-rate energy storage subsystem. Once the low-rate energy storage subsystem is fully charged, the high-rate energy storage subsystem is charged again, until the high-rate energy storage subsystem is fully charged.

[0198] The first control strategy determines the specific use of the sub-unit:

[0199] If not, determine whether the first charging energy is greater than the low-rate charging energy;

[0200] If so, the low-rate energy storage subsystem is charged first, and the charging time is based on the greater of the second charging energy and the third charging energy for the low-rate energy storage subsystem. When the high-rate and low-rate energy storage systems have a discharge requirement, the high-rate energy storage subsystem is controlled to discharge. When the high-rate energy storage subsystem has a low power, the high-rate energy storage subsystem is charged first, and the low-rate energy storage subsystem is charged only after the discharge function of the high-rate energy storage subsystem is satisfied.

[0201] The first control strategy determines the specific use of the sub-unit:

[0202] If the first charging energy is not greater than the low-rate charging energy, then determine whether the sum of the first charging energy and the high-rate charging energy is greater than the low-rate charging energy.

[0203] If so, the low-rate energy storage subsystem is charged first, and the charging time is based on the greater of the second charging energy and the third charging energy for charging the low-rate energy storage subsystem; when the high-rate and low-rate energy storage systems have a discharge demand, the high-rate energy storage subsystem is controlled to discharge; when the high-rate and low-rate energy storage systems do not have a discharge demand, the high-rate energy storage subsystem is controlled to charge the low-rate energy storage subsystem until the remaining energy in the high-rate energy storage subsystem is transferred to the low-rate energy storage subsystem.

[0204] The first control strategy determines the specific use of the sub-unit:

[0205] If not, the high-rate energy storage subsystem is charged first, and the charging time is based on the larger of the second charging energy and the third charging energy for the high-rate energy storage subsystem. When the high-rate energy storage subsystem is fully charged, the low-rate energy storage subsystem is then charged.

[0206] To further optimize the above embodiments, the control unit 604 is specifically used for:

[0207] The high- and low-rate energy storage systems are controlled primarily for discharging, and the energy of the high- and low-rate energy storage systems is combined with different time scales of the energy storage charge-discharge curve for charge-discharge control, wherein the low-rate energy storage subsystem is primarily for discharging.

[0208] The control unit 604 may specifically include:

[0209] The second acquisition subunit is used to acquire the high-rate undischarged energy of the high-rate energy storage subsystem and the low-rate undischarged energy of the low-rate energy storage subsystem.

[0210] The second division subunit is used to divide the energy storage charge and discharge curve into long time scale, medium time scale and short time scale according to a preset division standard.

[0211] The second charging energy determination subunit is used to determine the first discharge energy corresponding to the long time scale, the second discharge energy corresponding to the medium time scale, and the third discharge energy corresponding to the short time scale.

[0212] The second control strategy determination subunit is used to determine the second charge and discharge control strategy for the high-rate energy storage subsystem and the low-rate energy storage subsystem when the high-rate and low-rate energy storage systems are mainly discharging.

[0213] The charging and discharging duration in the second charging and discharging control strategy is determined based on the relationship between the second discharge energy and the third discharge energy.

[0214] To further optimize the above embodiments, the second control strategy determining subunit is specifically used for:

[0215] Determine whether the first discharge energy is greater than the sum of the high-rate discharge energy and the low-rate discharge energy;

[0216] If so, the low-rate energy storage subsystem is controlled to discharge only, while the high-rate energy storage subsystem is controlled to charge and discharge independently. The charging and discharging duration is determined by the larger of the second discharge energy and the third discharge energy for the high-rate energy storage subsystem, until both the high-rate energy storage subsystem and the low-rate energy storage subsystem are depleted.

[0217] To further optimize the above embodiments, the second control strategy determining subunit is further used for:

[0218] If not, determine whether the first discharge energy is greater than the low-rate discharge energy;

[0219] If so, the low-rate energy storage subsystem is discharged first, and the discharge duration is based on the larger of the second discharge energy and the third discharge energy for the low-rate energy storage subsystem to discharge. The high-rate energy storage subsystem is controlled to discharge. When the high-rate energy storage subsystem is about to be fully charged, the high-rate energy storage subsystem is discharged first to ensure that the low-rate energy storage subsystem only discharges.

[0220] To further optimize the above embodiments, the second control strategy determining subunit is further used for:

[0221] When the first discharge energy is not greater than the low-rate discharge energy, determine whether the sum of the first discharge energy and the high-rate discharge energy is greater than the low-rate discharge energy.

[0222] If so, the low-rate energy storage subsystem is discharged first, and the discharge duration is determined by the larger of the second discharge energy and the third discharge energy for the low-rate energy storage subsystem to discharge; when the high- and low-rate energy storage systems have a charging demand, the high-rate energy storage subsystem is charged; when the high- and low-rate energy storage systems do not have a charging demand, the low-rate energy storage subsystem is controlled to discharge to the high-rate energy storage subsystem.

[0223] To further optimize the above embodiments, the second control strategy determining subunit is further used for:

[0224] If not, the high-rate energy storage subsystem is discharged first, and the charging and discharging time is the larger of the second discharge energy and the third discharge energy for the high-rate energy storage subsystem. When the high-rate energy storage subsystem is emptied, the low-rate energy storage subsystem is then discharged.

[0225] It should be noted that for the specific working principles of each component in the device embodiment, please refer to the corresponding section of the method embodiment, which will not be repeated here.

[0226] Corresponding to the above embodiments, the present invention also discloses an energy storage system, which includes the control device in the above embodiments. For the specific working principle, please refer to the corresponding part of the above embodiments, which will not be repeated here.

[0227] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0228] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0229] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for an energy storage system, characterized in that, The method is applied to high- and low-rate energy storage systems, which include a high-rate energy storage subsystem and a low-rate energy storage subsystem. Predict the grid load curve and the generation curve of the generation side for a preset future time period; Based on the grid-side load curve and the power generation curve, the energy storage charge and discharge curve of the high- and low-rate energy storage system is generated in the preset future time period. Based on the relationship between the current state of charge of the low-rate energy storage subsystem and the minimum and maximum thresholds of the low-rate state of charge, it is determined whether the high-rate or low-rate energy storage system enters a scenario dominated by charging or discharging. When the high- and low-rate energy storage system enters a scenario dominated by charging or discharging, the corresponding high- and low-rate control strategy is determined based on the energy storage charge-discharge curve.

2. The control method according to claim 1, characterized in that, The step of determining whether the high- and low-rate energy storage systems enter a scenario primarily for charging or discharging based on the relationship between the current state of charge of the low-rate energy storage subsystem and the minimum and maximum thresholds of the low-rate state of charge, respectively, includes: When the current state of charge is not greater than the minimum threshold of the low-rate state of charge, the high-low rate energy storage system is determined to enter a charging-oriented scenario. When the current state of charge is not less than the maximum threshold of the low-rate state of charge, the high- and low-rate energy storage system is determined to enter a scenario dominated by discharge.

3. The control method according to claim 1, characterized in that, When the high- and low-rate energy storage system enters a scenario primarily focused on charging or discharging, the corresponding high- and low-rate control strategy is determined based on the energy storage charge-discharge curve, including: When the high- and low-rate energy storage system enters a scenario primarily focused on charging, a high- and low-rate control strategy for the energy storage system, primarily focused on charging, is adopted based on the energy storage charge-discharge curve. Specifically, this includes: The high and low rate energy storage system is controlled primarily for charging, and the energy of the high and low rate energy storage system is combined with different time scales of the energy storage charge and discharge curve for charge and discharge control.

4. The control method according to claim 3, characterized in that, The control of the high- and low-rate energy storage system is primarily based on charging. This involves combining the energy of the high- and low-rate energy storage system with different time scales of the energy storage charge-discharge curve for charge-discharge control, including: Obtain the high-rate energy to be charged from the high-rate energy storage subsystem and the low-rate energy to be charged from the low-rate energy storage subsystem; The energy storage charge and discharge curves are divided into long time scales, medium time scales, and short time scales according to a preset division standard. Determine the first charging energy corresponding to the long time scale, the second charging energy corresponding to the medium time scale, and the third charging energy corresponding to the short time scale; When the high- and low-rate energy storage system is mainly charging, a first charging and discharging control strategy for the high-rate energy storage subsystem and the low-rate energy storage subsystem is determined based on the relationship between the first charging energy, the high-rate energy to be charged, and the low-rate energy to be charged. The charging and discharging duration in the first charging and discharging control strategy is determined based on the relationship between the second charging energy and the third charging energy.

5. The control method according to claim 4, characterized in that, The preset division criterion is: based on the sign of the charging and discharging current and the minimum time scale T. delta When nT delta When the charging and discharging modes switch, the time scales are divided into high, medium and low according to the size of n. If nT delta If there is no change in current direction, then n1 is represented as the long time-scale coefficient, n2 as the medium time-scale coefficient, and n3 as the low time-scale coefficient, where n1 > n2 > n3, to ensure that the minimum time interval is not lower than the minimum time-scale discrimination T. min ; Correspondingly, n1T delta Representing the time scale, n2T delta Indicates the time scale, n3T delta This indicates the short time scale.

6. The control method according to claim 4, characterized in that, When the high- and low-rate energy storage systems are primarily engaged in charging, a first charge-discharge control strategy is determined for the high-rate energy storage subsystem and the low-rate energy storage subsystem based on the relationship between the first charging energy, the high-rate energy to be charged, and the low-rate energy to be charged. This strategy includes: Determine whether the first charging energy is greater than the sum of the high-rate charging energy and the low-rate charging energy; If so, then, provided that the high-rate energy storage subsystem's power capacity meets the requirements of the long-term discharge conditions, the high-rate energy storage subsystem is charged and discharged first, and then the low-rate energy storage subsystem is charged. The charging time is based on the larger of the second charging energy and the third charging energy for the low-rate energy storage subsystem. Once the low-rate energy storage subsystem is fully charged, the high-rate energy storage subsystem is charged again, until the high-rate energy storage subsystem is fully charged.

7. The control method according to claim 6, characterized in that, The first charge / discharge control strategy also includes: If not, determine whether the first charging energy is greater than the low-rate charging energy; If so, the low-rate energy storage subsystem is charged first, and the charging time is based on the greater of the second charging energy and the third charging energy for the low-rate energy storage subsystem. When the high-rate and low-rate energy storage systems have a discharge requirement, the high-rate energy storage subsystem is controlled to discharge. When the high-rate energy storage subsystem has a low power, the high-rate energy storage subsystem is charged first, and the low-rate energy storage subsystem is charged only after the discharge function of the high-rate energy storage subsystem is satisfied.

8. The control method according to claim 7, characterized in that, The first charge / discharge control strategy also includes: If the first charging energy is not greater than the low-rate charging energy, then determine whether the sum of the first charging energy and the high-rate charging energy is greater than the low-rate charging energy. If so, the low-rate energy storage subsystem is charged first, and the charging time is based on the greater of the second charging energy and the third charging energy for charging the low-rate energy storage subsystem; when the high-rate and low-rate energy storage systems have a discharge demand, the high-rate energy storage subsystem is controlled to discharge; when the high-rate and low-rate energy storage systems do not have a discharge demand, the high-rate energy storage subsystem is controlled to charge the low-rate energy storage subsystem until the remaining energy in the high-rate energy storage subsystem is transferred to the low-rate energy storage subsystem.

9. The control method according to claim 8, characterized in that, The first charge / discharge control strategy also includes: If not, the high-rate energy storage subsystem is charged first, and the charging time is based on the larger of the second charging energy and the third charging energy for the high-rate energy storage subsystem. When the high-rate energy storage subsystem is fully charged, the low-rate energy storage subsystem is then charged.

10. The control method according to claim 1, characterized in that, When the high- and low-rate energy storage system enters a scenario primarily focused on charging or discharging, the corresponding high- and low-rate control strategy is determined based on the energy storage charge-discharge curve, including: When the high- and low-rate energy storage system enters a scenario dominated by discharging, a high- and low-rate control strategy for the energy storage system, which is dominated by discharging, is adopted based on the energy storage charge-discharge curve. Specifically, this includes: The high- and low-rate energy storage systems are controlled primarily for discharging, and the energy of the high- and low-rate energy storage systems is combined with different time scales of the energy storage charge-discharge curve for charge-discharge control, wherein the low-rate energy storage subsystem is primarily for discharging.

11. The control method according to claim 10, characterized in that, The control of the high- and low-rate energy storage system primarily involves discharging, and the energy of the high- and low-rate energy storage system is combined with different time scales of the energy storage charge-discharge curve for charge-discharge control, including: Obtain the high-rate undischargeable energy of the high-rate energy storage subsystem and the low-rate undischargeable energy of the low-rate energy storage subsystem; The energy storage charge and discharge curves are divided into long time scales, medium time scales, and short time scales according to a preset division standard. Determine the first discharge energy corresponding to the long time scale, the second discharge energy corresponding to the medium time scale, and the third discharge energy corresponding to the short time scale; When the high- and low-rate energy storage system is mainly discharging, a second charging and discharging control strategy for the high-rate energy storage subsystem and the low-rate energy storage subsystem is determined based on the relationship between the first discharge energy, the high-rate energy to be discharged, and the low-rate energy to be discharged. The charging and discharging duration in the second charging and discharging control strategy is determined based on the relationship between the second discharge energy and the third discharge energy.

12. The control method according to claim 11, characterized in that, When the high-rate and low-rate energy storage systems are primarily discharging, a second charge-discharge control strategy is determined for the high-rate and low-rate energy storage subsystems based on the relationship between the first discharge energy, the high-rate energy to be discharged, and the low-rate energy to be discharged. This strategy includes: Determine whether the first discharge energy is greater than the sum of the high-rate discharge energy and the low-rate discharge energy; If so, the low-rate energy storage subsystem is controlled to discharge only, while the high-rate energy storage subsystem is controlled to charge and discharge independently. The charging and discharging duration is determined by the larger of the second discharge energy and the third discharge energy for the high-rate energy storage subsystem, until both the high-rate energy storage subsystem and the low-rate energy storage subsystem are depleted.

13. The control method according to claim 12, characterized in that, The second charge / discharge control strategy also includes: If not, determine whether the first discharge energy is greater than the low-rate discharge energy; If so, the low-rate energy storage subsystem is controlled to discharge first, and the discharge duration is based on the larger of the second discharge energy and the third discharge energy for the low-rate energy storage subsystem to discharge. The high-rate energy storage subsystem is controlled to charge and discharge. When the high-rate energy storage subsystem is about to be fully charged, the high-rate energy storage subsystem is used to discharge first, ensuring that the low-rate energy storage subsystem only discharges.

14. The control method according to claim 13, characterized in that, The second charge / discharge control strategy also includes: When the first discharge energy is not greater than the low-rate discharge energy, determine whether the sum of the first discharge energy and the high-rate discharge energy is greater than the low-rate discharge energy. If so, the low-rate energy storage subsystem is discharged first, and the discharge duration is the greater of the second discharge energy and the third discharge energy for the low-rate energy storage subsystem to discharge; when the high-rate and low-rate energy storage systems have a charging demand, the high-rate energy storage subsystem is charged; when the high-rate and low-rate energy storage systems do not have a charging demand, the low-rate energy storage subsystem is controlled to discharge to the high-rate energy storage subsystem.

15. The control method according to claim 14, characterized in that, The second charge / discharge control strategy also includes: If not, the high-rate energy storage subsystem is discharged first, and the discharge duration is the greater of the second discharge energy and the third discharge energy for the high-rate energy storage subsystem to discharge. When the high-rate energy storage subsystem is emptied, the low-rate energy storage subsystem is then discharged.

16. A control device for an energy storage system, characterized in that, This is applied to high- and low-rate energy storage systems, which include a high-rate energy storage subsystem and a low-rate energy storage subsystem. The control device includes: The curve prediction unit is used to predict the grid-side load curve and the generation curve of the generation side for a preset future time period. The curve generation unit is used to generate the energy storage charge and discharge curve of the high- and low-rate energy storage system in the preset future time period based on the grid-side load curve and the generation-side power generation curve. The charging and discharging scenario determination unit is used to determine whether the high- and low-rate energy storage system enters a scenario dominated by charging or a scenario dominated by discharging, based on the relationship between the current state of charge of the low-rate energy storage subsystem and the minimum threshold and maximum threshold of the low-rate state of charge. The control unit is used to determine the corresponding high- or low-rate control strategy based on the energy storage charge-discharge curve when the high- or low-rate energy storage system enters a scenario dominated by charging or discharging.

17. An energy storage system, characterized in that, include: The control device as claimed in claim 16.

Images