Energy storage control method and energy storage system

Abstract

The invention discloses an energy storage control method and an energy storage system, and the method comprises the steps: determining the power-on operation of the energy storage system, and obtaining the online number of energy storage cabinets in the energy storage system, the target total active power of the energy storage system, the SOH (state of health) value of each energy storage cabinet, and the SOC (state of charge) value of each energy storage cabinet; obtaining an average SOH value according to the online number and the SOH value, obtaining a first difference value between the SOH value and the average SOH value, obtaining an average SOC value according to the online number and the SOC value, and obtaining a second difference value between the SOC value and the average SOC value; and calculating a target power value of each energy storage cabinet according to the target total active power, the online number, the average power value, the first difference value, the second difference value, a preset SOH threshold value, a preset SOC threshold value and a preset distribution coefficient. The energy storage control method is flexible in application and high in applicability, the SOH consistency of all the energy storage cabinets can be effectively improved through long-time operation, and then the linearity of the energy storage system is improved.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to an energy storage control method and an energy storage system. Background Technology

[0002] To improve the capacity and reliability of energy storage systems, commercial and industrial outdoor integrated cabinet energy storage systems generally adopt a multi-unit parallel application strategy. However, in existing technologies, the control strategies for multi-unit parallel applications in energy storage systems are mostly relatively simple and lack standardized specifications, making their application inflexible. Furthermore, with increased operating time and the need for subsequent system expansion, differences in the State of Harmony (SOH) of each energy storage cabinet within the system will arise, and these differences will increase over time. When these differences reach a certain level, they will severely affect the system's linearity. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, the first objective of this invention is to propose an energy storage control method that meets the power distribution requirements of energy storage systems with multiple energy storage cabinets, is flexible in application, highly applicable, and can effectively improve the consistency of the State of Harmony (SOH) of each energy storage cabinet during long-term operation, thereby improving the linearity of the energy storage system.

[0004] The second objective of this invention is to provide an energy storage system.

[0005] To achieve the above objectives, a first aspect of the present invention provides an energy storage control method, the control method comprising: determining that an energy storage system is powered on and operating; acquiring the number of online energy storage cabinets in the energy storage system, the target total active power of the energy storage system, the SOH value of each energy storage cabinet, and the SOC value of each energy storage cabinet; acquiring an average SOH value based on the number of online cabinets and the SOH value, and acquiring a first difference between the SOH value and the average SOH value; acquiring an average SOC value based on the number of online cabinets and the SOC value, and acquiring a second difference between the SOC value and the average SOC value; and calculating a target power value for each energy storage cabinet based on the target total active power, the number of online cabinets, the average power value, the first difference, the second difference, a preset SOH threshold, a preset SOC threshold, and a preset allocation coefficient.

[0006] The energy storage control method proposed in this embodiment of the invention calculates the target power value of each energy storage cabinet by acquiring data such as the number of online energy storage cabinets in the energy storage system, the target total active power of the energy storage system, the SOH value of each energy storage cabinet, the SOC value of each energy storage cabinet, and the first difference between the SOH value and the average SOH value, the average SOC value, and the second difference between the SOC value and the average SOC value. By adopting a power allocation strategy based on the SOH and SOC of the energy storage cabinets, a reasonable allocation of the target power value of each energy storage cabinet can be achieved. Long-term operation can effectively improve the consistency of the SOH of each energy storage cabinet, meeting the power allocation requirements of energy storage systems with multiple energy storage cabinets. It is flexible in application and highly applicable. Furthermore, by accurately calculating the target power value of each energy storage cabinet, the power of the energy storage system can be regulated, extending the service life of the energy storage cabinets and thus improving the linearity of the energy storage system.

[0007] In some embodiments of the present invention, the preset SOH threshold includes a first SOH threshold and a second SOH threshold, wherein the first SOH threshold is less than the second SOH threshold; the preset allocation coefficient includes a first SOH allocation coefficient and a second SOH allocation coefficient, wherein the first SOH allocation coefficient is greater than the second SOH allocation coefficient.

[0008] In some embodiments of the present invention, calculating the target power value of each energy storage cabinet based on the target total active power, the number of online cabinets, the average power value, the first difference, the second difference, a preset SOH threshold, a preset SOC threshold, and a preset allocation coefficient includes: determining that the absolute value of the second difference of the energy storage cabinet is less than or equal to the preset SOC threshold; and calculating the target power value of each energy storage cabinet based on the target total active power, the number of online cabinets, the average power value, the first difference, the first SOH threshold, the second SOH threshold, the first SOH allocation coefficient, and the second SOH allocation coefficient.

[0009] In some embodiments of the present invention, calculating the target power value of each energy storage cabinet based on the target total active power, the number of online units, the average power value, the first difference, the first SOH threshold, the second SOH threshold, the first SOH allocation coefficient, and the second SOH allocation coefficient includes: determining that the absolute value of the first difference of the energy storage cabinet is greater than the second SOH threshold, and the first target power value P1 of the energy storage cabinet satisfies... Where Paverage is the average power value. Let K1 be the first difference value of the x-th energy storage cabinet, and K1 be the first SOH allocation coefficient; or, determine that the absolute value of the first difference value of the energy storage cabinet is greater than the first SOH threshold and less than or equal to the second SOH threshold, and the second target power value P2 of the energy storage cabinet satisfies Wherein, K2 is the second SOH allocation coefficient; or, determine that the absolute value of the first difference of the energy storage cabinet is less than or equal to the first SOH threshold, obtain the remaining target active power value according to the target total active power, all the first target power values, and all the second target power values, and perform power average allocation on the energy storage cabinets that satisfy the condition that the absolute value of the first difference is less than or equal to the first SOH threshold according to the remaining target active power value.

[0010] In some embodiments of the present invention, the preset allocation coefficient further includes a preset SOC allocation coefficient; it is determined that the absolute value of the second difference of the energy storage cabinet is greater than the preset SOC threshold; the target power value of each energy storage cabinet is calculated based on the target total active power, the number of online units, the average power value, the first difference, the second difference, the first SOH threshold, the second SOH threshold, the first SOH allocation coefficient, the second SOH allocation coefficient, and the preset SOC allocation coefficient.

[0011] In some embodiments of the present invention, calculating the target power value of each energy storage cabinet based on the target total active power, the number of online units, the average power value, the first difference, the second difference, the first SOH threshold, the second SOH threshold, the first SOH allocation coefficient, the second SOH allocation coefficient, and the preset SOC allocation coefficient includes: determining that the absolute value of the first difference of the energy storage cabinet is greater than the second SOH threshold, and the third target power value P3 of the energy storage cabinet satisfies... Where Paverage is the average power value. Let x be the first difference value of the xth energy storage cabinet. Let K1 be the second difference of the x-th energy storage cabinet, K1 be the first SOH allocation coefficient, and f be the preset SOC allocation coefficient; or, determine that the absolute value of the first difference of the energy storage cabinet is greater than the first SOH threshold and less than or equal to the second SOH threshold, and the fourth target power value P4 of the energy storage cabinet satisfies Where K2 is the second SOH allocation coefficient; or, if the absolute value of the first difference of the energy storage cabinet is less than or equal to the first SOH threshold, the fifth target power value P5 of the energy storage cabinet satisfies... .

[0012] In some embodiments of the present invention, the preset allocation coefficient further includes a preset SOH power adjustment hysteresis value and a preset SOC power adjustment hysteresis value; a third difference between the first SOH threshold and the preset SOH power adjustment hysteresis value, a fourth difference between the second SOH threshold and the preset SOH power adjustment hysteresis value, and a fifth difference between the preset SOC threshold and the preset SOC power adjustment hysteresis value are obtained.

[0013] In some embodiments of the present invention, it is determined that the operating time of the energy storage system reaches a preset time threshold, and the first difference and the second difference of the energy storage cabinet are reacquired; the target power value of the energy storage cabinet is adjusted according to the first difference, the third difference and / or the fourth difference, or the target power value of the energy storage cabinet is adjusted according to the second difference and the fifth difference.

[0014] To achieve the above objectives, a second aspect of the present invention also provides an energy storage system, comprising: a transformer disposed on an AC bus; a gate meter connected to the AC bus; a main energy storage cabinet connected to both the AC bus and the gate meter, the main energy storage cabinet being used to execute the energy storage control method described in any of the preceding embodiments; and at least one slave energy storage cabinet connected to the AC bus, the gate meter, and the main energy storage cabinet.

[0015] The energy storage system proposed in this embodiment includes a main energy storage cabinet and at least one slave energy storage cabinet. By executing the energy storage control method described above, the main energy storage cabinet can accurately calculate the target power values ​​of the main energy storage cabinet and at least one slave energy storage cabinet, thereby achieving a reasonable allocation of the target power values ​​for each energy storage cabinet. Long-term operation can also effectively improve the consistency of the State of Harmony (SOH) of each energy storage cabinet, meeting the power allocation requirements of energy storage systems with multiple energy storage cabinets. Furthermore, it is flexible in application and highly applicable. Moreover, it can achieve power regulation of the entire energy storage system, extending the service life of each energy storage cabinet, thereby improving the linearity of the energy storage system.

[0016] In some embodiments of the present invention, if the main energy storage cabinet is determined to be offline, at least one of the slave energy storage cabinets is used as the new main energy storage cabinet.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of an energy storage system according to an embodiment of the present invention; Figure 2 A flowchart of an energy storage control method according to an embodiment of the present invention; Figure 3 A flowchart of an energy storage control method according to another embodiment of the present invention; Figure 4 This is a flowchart of an energy storage control method according to yet another embodiment of the present invention.

[0019] Figure label: Energy storage system 1; Transformer 10, gate meter 20, main energy storage cabinet 30, slave energy storage cabinet 40; Energy storage cabinet 1, energy storage cabinet 2, energy storage cabinet n. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0021] In some embodiments of the present invention, an energy storage control method is proposed for an energy storage system. The following will first describe... Figure 1 Understand the structure and function of each part of the energy storage system in this embodiment of the invention. Figure 1 This is a schematic diagram of an energy storage system according to an embodiment of the present invention. The energy storage system 1 includes a transformer 10, a gate meter 20, a main energy storage cabinet 30, and at least one slave energy storage cabinet 40. The transformer 10 is disposed on the AC bus, the gate meter 20 is connected to the AC bus, the main energy storage cabinet 30 is connected to both the AC bus and the gate meter 20, and the main energy storage cabinet 30 is used to execute the energy storage control method of the embodiment of the present invention. At least one slave energy storage cabinet 40 is connected to the AC bus, the gate meter 20, and the main energy storage cabinet 30.

[0022] Specifically, the main energy storage cabinet 30 and the slave energy storage cabinet 40 are energy storage cabinets of the same specifications, with the main energy storage cabinet 30 controlling the slave energy storage cabinet 40. The AC sides of multiple energy storage cabinets are connected to the AC busbar. The gate meter 20 is installed on the low-voltage side of the transformer 10, at the load front end. The gate meter 20 can be connected to the main energy storage cabinet 30 and the slave energy storage cabinet 40 via RS485, primarily for monitoring the power consumption of the plant area. The main energy storage cabinet 30 periodically reads the power data from the gate meter 20. It is understood that only the main energy storage cabinet 30 communicates with the gate meter 20 at any given time; communication between the slave energy storage cabinet 40 and the gate meter 20 is not enabled. When the power of the gate meter 20 is too high, it limits the charging power of the energy storage system 1; when the power of the gate meter 20 approaches 0 kW, it limits the discharging power of the energy storage system 1, thereby achieving charging and discharging protection for the energy storage system 1. The main energy storage cabinet 30 and the slave energy storage cabinet 40 are connected to the same network segment via a switch, enabling data exchange. The main energy storage cabinet 30 periodically counts the number of slave energy storage cabinets 40 online. That is, when the energy storage system 1 has been running for a certain period of time, the main energy storage cabinet 30 will re-acquire the number of slave energy storage cabinets 40 online. Therefore, the energy storage control method of this embodiment can meet the needs of subsequent expansion of the energy storage system 1.

[0023] In some embodiments of the present invention, when it is determined that the main energy storage cabinet 30 is offline, one of the multiple slave energy storage cabinets 40 is selected as a new main energy storage cabinet 30 to implement the energy storage control method of the following embodiments.

[0024] Specifically, adopting a master-slave control architecture can improve the scientific nature of power allocation and facilitate user operation. However, in master-slave mode, if the master energy storage cabinet 30 malfunctions, the entire energy storage system 1 will stop operating, affecting revenue. To address the issue of the entire energy storage system 1 stopping due to a master energy storage cabinet malfunction in the master-slave architecture, thus impacting customer revenue, a master-slave adaptive adjustment technology can be used. Once it is determined that the master energy storage cabinet 30 is offline, at least one slave energy storage cabinet 40 becomes the new master energy storage cabinet 30, identifies and executes the tasks of the master energy storage cabinet 30, removes the malfunctioning energy storage cabinet from the operating array, and allows the remaining energy storage cabinets to operate as planned, thereby improving the online rate of energy storage system 1.

[0025] Furthermore, when the energy storage system 1 is operating normally, it is only necessary to set the total planned power curve on the main energy storage cabinet 30. The main energy storage cabinet 30 will send the relevant settings to each slave energy storage cabinet 40 for backup. At the same time, the main energy storage cabinet 30 will determine the number of online energy storage cabinets in the energy storage system 1, and then allocate the total power to each online energy storage cabinet. The specific implementation strategy is as follows.

[0026] The following is for reference. Figures 2-4 An energy storage control method according to an embodiment of the present invention is described.

[0027] like Figure 2 The diagram shown is a flowchart of an energy storage control method according to an embodiment of the present invention. The energy storage control method includes at least steps S1-S3, as detailed below.

[0028] S1, determine that the energy storage system is powered on and running, and obtain the number of online energy storage cabinets in the energy storage system, the target total active power of the energy storage system, the SOH value of each energy storage cabinet, and the SOC value of each energy storage cabinet.

[0029] Specifically, taking an energy storage system comprising n energy storage cabinets as an example, SOH1 represents the SOH value of energy storage cabinet 1, SOH2 represents the SOH value of energy storage cabinet 2, and SOHn represents the SOH value of energy storage cabinet n; SOC1 represents the SOC value of energy storage cabinet 1, SOC2 represents the SOC value of energy storage cabinet 2, and SOCn represents the SOC value of energy storage cabinet n.

[0030] S2, obtain the average SOH value based on the number of online users and the SOH value, and obtain the first difference between the SOH value and the average SOH value; and obtain the average SOC value based on the number of online users and the SOC value, and obtain the second difference between the SOC value and the average SOC value.

[0031] For example, SOHsum represents the sum of the SOH values ​​of all currently online energy storage units. Assuming the energy storage system includes energy storage unit 1, energy storage unit 2, ..., energy storage unit n, and all n energy storage units are online, then SOHsum = SOH1 + SOH2 + ... + SOHn. Furthermore, the average SOH value can be expressed as SOHaverage, which is equal to SOHsum divided by the number of online energy storage units. The first difference representing the x-th energy storage unit is also the value of energy storage unit x. ,For example, This is the first difference for energy storage cabinet 1. SOH2 is the first difference for energy storage cabinet 2… SOHn represents the first difference of energy storage cabinet n.

[0032] Similarly, SOCsum represents the sum of the SOC values ​​of all currently online energy storage units. Assuming the energy storage system includes unit 1, unit 2, ..., unit n, and all n units are online, then SOCsum = SOC1 + SOC2 + ... + SOCn. Furthermore, the average SOC value can be expressed as SOCaverage, which is equal to SOCsum divided by the number of online energy storage units. The second difference representing the x-th energy storage unit is also the value of energy storage unit x. SOC, for example SOC1 is the second difference value of energy storage cabinet 1. SOC2 is the second difference for energy storage cabinet 2… SOCn represents the second difference of energy storage cabinet n.

[0033] S3 calculates the target power value of each energy storage cabinet based on the target total active power, number of online units, average power value, first difference, second difference, preset SOH threshold, preset SOC threshold, and preset allocation coefficient.

[0034] The energy storage control method proposed in this embodiment of the invention calculates the target power value of each energy storage cabinet by acquiring data such as the number of online energy storage cabinets in the energy storage system, the target total active power of the energy storage system, the SOH value of each energy storage cabinet, the SOC value of each energy storage cabinet, and the first difference between the SOH value and the average SOH value, the average SOC value, and the second difference between the SOC value and the average SOC value. By adopting a power allocation strategy based on the SOH and SOC of the energy storage cabinets, a reasonable allocation of the target power value of each energy storage cabinet can be achieved. Long-term operation can effectively improve the consistency of the SOH of each energy storage cabinet, meeting the power allocation requirements of energy storage systems with multiple energy storage cabinets. It is flexible in application and highly applicable. Furthermore, by accurately calculating the target power value of each energy storage cabinet, the power of the energy storage system can be regulated, extending the service life of the energy storage cabinets and thus improving the linearity of the energy storage system.

[0035] Furthermore, based on the above, the energy storage system 1 proposed according to the embodiments of the present invention includes a main energy storage cabinet 30 and at least one slave energy storage cabinet 40. The main energy storage cabinet 30, by executing the energy storage control method of the above embodiments of the present invention, can accurately calculate the target power values ​​of the main energy storage cabinet 30 and at least one slave energy storage cabinet 40, thereby achieving a reasonable allocation of the target power values ​​of each energy storage cabinet. Long-term operation can also effectively improve the consistency of the State of Harmony (SOH) of each energy storage cabinet, meeting the power allocation requirements of the energy storage system 1 with multiple energy storage cabinets. It is also flexible in application and highly applicable. Moreover, it can achieve power regulation of the entire energy storage system 1, extending the service life of each energy storage cabinet, thereby improving the linearity of the energy storage system 1.

[0036] In some embodiments of the present invention, the preset SOH threshold includes a first SOH threshold and a second SOH threshold, wherein the first SOH threshold is less than the second SOH threshold; the preset allocation coefficient includes a first SOH allocation coefficient and a second SOH allocation coefficient, wherein the first SOH allocation coefficient is greater than the second SOH allocation coefficient.

[0037] Specifically, SOH_tha represents the preset SOH threshold, and SOH_tha > 0. The number of preset SOH thresholds and their relative values ​​can be controlled based on calculations. For example, 'a' can be 1, 2, 3…, representing SOH_th1, SOH_th2, SOH_th3… respectively, and SOH_th1 < SOH_th2 < SOH_th3…

[0038] In some embodiments of the present invention, SOH_th can be set to include SOH_th1 and SOH_th2, wherein SOH_th1 is a first SOH threshold, SOH_th2 is a second SOH threshold, and the first SOH threshold is less than the second SOH threshold.

[0039] Furthermore, SOC_thb represents a preset SOC threshold, and b can be 1, 2, 3..., representing SOC_th1, SOC_th2, SOC_th3... respectively, with SOC_th1 < SOC_th2 < SOC_th3... In some embodiments of the present invention, SOC_thb can be set to include SOC_th1, where SOC_th1 is a first SOC threshold.

[0040] Furthermore, the preset allocation coefficient includes a power allocation coefficient based on SOH, which is denoted as K and K > 0. The power allocation coefficient based on SOH may include a first SOH allocation coefficient K1 and a second SOH allocation coefficient K2, and K1 is greater than K2. K1 and K2 can be set according to requirements, without specific limitations here.

[0041] The following embodiments of the present invention are described using the following examples: a preset SOH threshold including a first SOH threshold and a second SOH threshold; and a preset SOC threshold including a first SOC threshold. The first SOH threshold is SOH_th1, the second SOH threshold is SOH_th2, SOH_th1 < SOH_th2, and the preset SOC threshold is SOC_th1. In practical applications, the actual online power of each energy storage cabinet needs to be considered to limit power allocation. Therefore, power allocation requires setting specific values ​​for SOH_th1, SOH_th2, and SOC_th1. For example, SOH_th1 can be set to 3%-5%, SOH_th2 can be set to 5%-8%, and SOC_th1 can be set to 5%-10%.

[0042] In some embodiments, such as Figure 3 The diagram shows a flowchart of an energy storage control method according to another embodiment of the present invention. In this method, the target power value of each energy storage cabinet is calculated based on the target total active power, the number of online units, the average power value, the first difference, the second difference, the preset SOH threshold, the preset SOC threshold, and the preset allocation coefficient. Specifically, step S3 above may include steps S311 and S312.

[0043] S311, determine that the absolute value of the second difference of the energy storage cabinet is less than or equal to the preset SOC threshold.

[0044] Specifically, | SOCx| represents the absolute value of the second difference between the SOC value of energy storage unit x and the average SOC value, that is, the absolute value of the second difference. When the second difference of any energy storage unit satisfies | When SOCx|≤SOC_th1, step S312 can be executed.

[0045] It should be noted that the energy storage control method proposed in this embodiment of the invention is actually a power allocation strategy based on SOH and SOC. Under normal conditions, it is usually first based on... The power allocation value is adjusted within a certain range to perform an initial power allocation, and then redistributed based on the State of Charge (SOC). However, it is understandable that when energy storage system 1 is initially powered on, all energy storage cabinets are fully charged, and the initial SOC of each cabinet is 100%. Therefore, the power allocation can be adjusted based on the SOC of the energy storage cabinets. The power allocation value is adjusted according to the range of the energy storage cabinet. In other words, the following is based first on the energy storage cabinet's... The control method for adjusting the power allocation value within the range is actually carried out under the condition that the absolute value of the second difference of the energy storage cabinet is less than or equal to the preset SOC threshold.

[0046] S312, calculate the target power value of each energy storage cabinet based on the target total active power, number of online units, average power value, first difference, first SOH threshold, second SOH threshold, first SOH allocation coefficient and second SOH allocation coefficient.

[0047] Specifically, the target power value for each energy storage cabinet is calculated based on the target total active power, the number of online storage units, the average power value, the first difference, the first SOH threshold, the second SOH threshold, the first SOH allocation coefficient, and the second SOH allocation coefficient. This includes the following three cases: the absolute value of the first difference for each energy storage cabinet is greater than the second SOH threshold; the absolute value of the first difference for each energy storage cabinet is greater than the first SOH threshold but less than or equal to the second SOH threshold; and the absolute value of the first difference for each energy storage cabinet is less than or equal to the first SOH threshold. Where, | SOHx| represents the absolute value of the difference between the SOH value of energy storage cabinet x and the average SOH value, which is the absolute value of the first difference.

[0048] The following assumes that the second difference of all energy storage cabinets satisfies | This explanation is based on the premise that SOCx|≤SOC_th1.

[0049] Specifically, when all online energy storage cabinets Both SOH requirements are met. When SOHx|≤SOH_th2, power allocation is performed according to the following method: further judgment | The relationship between SOHx and SOH_th1, if all energy storage cabinets | SOHx|all satisfy| If SOHx|≤SOH_th1, it means that the SOH of each energy storage cabinet is not significantly different, and the power of each energy storage cabinet is controlled according to the average power Paverage.

[0050] Alternatively, if the absolute value of the first difference of the energy storage cabinet is determined to be greater than the first SOH threshold and less than or equal to the second SOH threshold, then the second target power value P2 of the energy storage cabinet satisfies... Where K2 is the second SOH allocation coefficient. That is, if there exists at least one locker satisfying SOH_th1 < | SOHx|≤SOH_th2 indicates that there are significant differences in the SOH of one or more energy storage cabinets. Therefore, for the condition SOH_th1<| For lockers where SOHx|≤SOH_th2, the operating power is calculated according to the second target power value. P2 = Paverage (1+) SOHx K2) is used for control.

[0051] Alternatively, determine that the absolute value of the first difference between the energy storage cabinets is less than or equal to the first SOH threshold. Obtain the remaining target active power value based on the total target active power, all first target power values, and all second target power values. Then, based on the remaining target active power value, perform power equalization on the energy storage cabinets that satisfy the condition that the absolute value of the first difference is less than or equal to the first SOH threshold. In other words, for at least one storage cabinet that satisfies SOH_th1 < | In the case where SOHx|≤SOH_th2, for other online energy storage cabinets, their | SOHx|all satisfy| If SOHx|≤SOH_th1, the power is then distributed evenly based on the remaining distributable power.

[0052] Alternatively, if the absolute value of the first difference in the energy storage cabinets is determined to be greater than the second SOH threshold, further power adjustment of the relevant energy storage cabinets is required based on the SOC difference. In this embodiment, the second difference of all energy storage cabinets satisfies | If SOCx|≤SOC_th1, then the first target power value P1 of the energy storage cabinet satisfies In other words, when there is at least one online energy storage cabinet... SOH satisfies | When SOHx|>SOH_th2, it indicates that the SOH of this energy storage cabinet differs significantly from that of other energy storage cabinets. Its operating power is then calculated according to the first target power value, P1=Paverage. (1+) SOHx K2) is used for control. Also, in the presence of at least one online energy storage cabinet... SOH satisfies | Given that SOHx|>SOH_th2, for other online energy storage cabinets, if there exists an energy storage cabinet with SOH_th1<| In the case where SOHx|≤SOH_th2, the second target power value is calculated using the method P2=Paverage in the above embodiment. (1+) SOHx K2) Calculate the target power value of the corresponding energy storage cabinet. Also, for other online energy storage cabinets, if there are still energy storage cabinets... SOH satisfies | If SOHx|≤SOH_th2, then the remaining distributable power is allocated equally.

[0053] In other embodiments of the present invention, the preset allocation coefficient further includes a preset SOC allocation coefficient. The preset allocation coefficient includes a SOC-based power allocation coefficient, which is denoted as f and f > 0. The SOC-based power allocation coefficient may include the preset SOC allocation coefficient f, and f can be set according to requirements, without specific limitations here.

[0054] like Figure 4 The diagram shown is a flowchart of an energy storage control method according to another embodiment of the present invention. Specifically, step S3 may further include steps S321 and S322.

[0055] S321, determine that the absolute value of the second difference of the energy storage cabinet is greater than the preset SOC threshold.

[0056] If the absolute value of the first difference between the energy storage cabinets is determined to be greater than the second SOH threshold, then at least one energy storage cabinet exists online. SOH satisfies | When SOHx|>SOH_th2, and further adjusts the power of the relevant energy storage cabinets based on the SOC difference, it is determined that there is a case where the absolute value of the second difference of at least one energy storage cabinet is greater than the preset SOC threshold. The following explanation is based on this case.

[0057] S322, calculate the target power value of each energy storage cabinet based on the target total active power, number of online units, average power value, first difference, second difference, first SOH threshold, second SOH threshold, first SOH allocation coefficient, second SOH allocation coefficient and preset SOC allocation coefficient.

[0058] Specifically, under the aforementioned preconditions, the first difference for all online energy storage cabinets may fall into one of the following three categories: the absolute value of the first difference of the energy storage cabinet is greater than the second SOH threshold; the absolute value of the first difference of the energy storage cabinet is greater than the first SOH threshold and less than or equal to the second SOH threshold; the absolute value of the first difference of the energy storage cabinet is less than or equal to the first SOH threshold.

[0059] The following is based on the existence of at least one online energy storage cabinet. SOH satisfies | The explanation is based on the premise that SOHx|>SOH_th2, and there exists at least one energy storage cabinet whose absolute value of the second difference is greater than the preset SOC threshold.

[0060] In some embodiments of the present invention, if the absolute value of the first difference of the online energy storage cabinet is determined to be greater than the second SOH threshold, the third target power value P3 of the energy storage cabinet is satisfied. Where Paverage is the average power value. This is the first difference value of the x-th energy storage cabinet. SOCx is the second difference of the x-th energy storage cabinet, K1 is the first SOH allocation coefficient, and f is the preset SOC allocation coefficient; or, if the absolute value of the first difference of the energy storage cabinet is greater than the first SOH threshold and less than or equal to the second SOH threshold, the fourth target power value P4 of the energy storage cabinet satisfies... Where K2 is the second SOH allocation coefficient; or, if the absolute value of the first difference of the energy storage cabinet is less than or equal to the first SOH threshold, the fifth target power value P5 of the energy storage cabinet satisfies... .

[0061] Based on the above, the calculation of the target power value of each energy storage cabinet in the energy storage system requires not only based on the SOH difference, but also on the SOC difference to adjust the power of the relevant energy storage cabinets. The power allocation based on SOH can gradually improve the consistency of the SOH of the energy storage system through long-term operation, while the power redistribution based on SOC is to meet the current total power demand.

[0062] In some embodiments of the present invention, the preset allocation coefficient further includes a preset SOH power adjustment hysteresis value and a preset SOC power adjustment hysteresis value; and obtains a third difference between a first SOH threshold and the preset SOH power adjustment hysteresis value, a fourth difference between a second SOH threshold and the preset SOH power adjustment hysteresis value, and a fifth difference between a preset SOC threshold and the preset SOC power adjustment hysteresis value.

[0063] The hysteresis value of the preset SOH power adjustment can be represented as SOH_thdiff, and the hysteresis value of the preset SOC power adjustment can be represented as SOC_thdiff. For example, SOC_thdiff can be set to 2%-3%, and SOH_thdiff can be set to 1%-2%. Furthermore, the third difference can be represented as SOH_th1-SOH_thdiff, the fourth difference as SOH_th2-SOH_thdiff, and the fifth difference as SOC_th1-SOC_thdiff.

[0064] Specifically, in practical applications, if no preset hysteresis value for SOH power regulation or a preset hysteresis value for SOC power regulation is set, for SOH_th1 < | For energy storage cabinets where SOH|≤SOH_th2, when the energy storage cabinet's | SOH|Satisfies| When SOH| < SOH_th1, the energy storage system will adjust the target power threshold of the energy storage cabinet; or, when SOH_th2 < | The SOH energy storage cabinet, when the energy storage cabinet's | SOH| satisfies SOH_th1<| When SOH|≤SOH_th2, the energy storage system will also adjust the target power value of the energy storage cabinet; or, when SOC_th1≤| SOC| energy storage cabinet, when the energy storage cabinet| SOC | Satisfies | When SOC| < SOC_th1, the energy storage system will also adjust the target power threshold of the energy storage cabinet. It is understandable that during actual operation, the || of each energy storage cabinet will be adjusted. SOH| and| The State of Charge (SOC) changes in real time, meaning that the three scenarios mentioned above may occur frequently. This necessitates frequent switching of the target power values ​​for each energy storage unit, increasing the computational load of the entire system and consequently raising the control cost of the energy storage system. Therefore, embodiments of this invention propose preset hysteresis values ​​SOH_thdiff for SOH power adjustment and SOC_thdiff for SOC power adjustment, for the energy storage unit's | SOH| and| SOC| represents the situation that changes in real time.

[0065] In some embodiments of the present invention, after determining that the operating time of the energy storage system has reached a preset time threshold, the first difference and the second difference of the energy storage cabinet are reacquired; the target power value of the energy storage cabinet is adjusted according to the first difference, the third difference, and / or the fourth difference, or the target power value of the energy storage cabinet is adjusted according to the second difference and the fifth difference. It is understood that the preset time threshold can be set as needed, and is not set here. For example, the preset time threshold can be a very short time, intended for real-time monitoring of the operating status of each energy storage cabinet. Alternatively, the preset time threshold can be set to 3 minutes, 5 minutes, 10 minutes, etc., for periodic detection and adjustment of the operating status of each energy storage cabinet.

[0066] Specifically, after a period of operation, the difference in the SOH value of the energy storage cabinet may increase, and its SOC value may change. Therefore, when the operating time of the energy storage system reaches a preset time threshold, the embodiments of the present invention will re-acquire the first difference and the second difference of the energy storage cabinet, and then adjust the target power value of the energy storage cabinet according to the first difference, the third difference and / or the fourth difference, or adjust the target power value of the energy storage cabinet according to the second difference and the fifth difference.

[0067] Specifically, for SOH_th1 < | For energy storage cabinets where SOH|≤SOH_th2, when the energy storage cabinet's | SOH|Satisfies| The target power value of the energy storage cabinet will only be adjusted when SOH| < SOH_th1 - SOH_thdiff; or, for SOH_th2 < | SOH| energy storage cabinet, when the energy storage cabinet| SOH|Satisfies| The target power value of the energy storage cabinet will only be adjusted when SOH| < SOH_th2 - SOH_thdiff; and for SOC_th1 ≤ | SOC| energy storage cabinet, when the energy storage cabinet| SOC | Satisfies | The target power value of the energy storage cabinet will only be adjusted when SOC| < SOC_th1 - SOC_thdiff. By setting the hysteresis value SOH_thdiff for SOH power adjustment and the preset hysteresis value SOC_thdiff for SOC power adjustment, over-adjustment of power distribution can be effectively avoided.

[0068] Based on the above, the hysteresis values ​​of the preset SOH power adjustment and the preset SOC power adjustment are used to control the adjustment frequency and prevent the power distribution from being too frequent, especially in critical states. Without hysteresis value judgment, the power will be adjusted when the threshold is exceeded and restored when the power is below the threshold, thus repeatedly controlling the power. The hysteresis value extends the running time after each power adjustment.

[0069] According to the energy storage control method proposed in the embodiments of the present invention, the following description takes the parallel operation of 5 energy storage cabinets in an energy storage system as an example. It is assumed that the target total active power Psum of the energy storage system is 300KW, and the energy storage system is in discharge operation. Specifically, the energy storage cabinet 4's | SOH4| satisfies SOH_th1<| SOH4|<SOH_th2, energy storage cabinet 5| SOH5|Satisfies| SOH5|>SOH_th2, the remaining online energy storage cabinets meet the requirements. Given that SOHx|≤SOH_th1, and the initial SOC of each energy storage cabinet is 100%, the power allocation for the first stage is as follows. The target power values ​​for energy storage cabinets 1-5 are represented as P1, P2, P3, P4, and P5, respectively.

[0070] Wherein, the average power value Paverage = Psum / n = 300 / 5 = 60KW; therefore, P4 = 60 (1+) SOH4 K2); P5=60 (1+) SOH5 K1); P1, P2, P3 = (300 – P4 – P5) / 3. Among them, during operation, the energy storage cabinet 4 experiences | If SOC4|>SOC_th1, then the power allocation in the second stage is as follows.

[0071] Specifically, P4=60 (1+) SOH4 K2+ SOC4 f); P5=60 (1+) SOH5 K1); P1, P2, P3 = (300 – P4 – P5) / 3. After running for a period of time, when | When SOC4| < SOC_th1 - SOC_thdiff, all energy storage cabinets resume the first stage of power allocation. And, when | When SOH4|<SOH_th1-SOH_thdiff, it means that the SOH difference of energy storage cabinet 4 has been reduced to a reasonable range, indicating that the adjustment is in place and the power is distributed evenly according to the remaining power.

[0072] And, after a period of operation, when the energy storage cabinet 5's | When SOH5| < SOH_th2 - SOH_thdiff, the target power value of energy storage cabinet 5 is adjusted to P5 = 60. (1+) SOH5 K2), and after a period of operation, when the energy storage cabinet 5's | When SOH5|<SOH_th1-SOH_thdiff, the target power value of energy storage cabinet 5 is distributed evenly according to the remaining power.

[0073] Other configurations and operations of the energy storage system 1 according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0074] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0075] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An energy storage control method, characterized in that, The control method includes: Determine that the energy storage system is powered on and running, and obtain the number of online energy storage cabinets in the energy storage system, the target total active power of the energy storage system, the SOH value of each energy storage cabinet, and the SOC value of each energy storage cabinet; The average SOH value is obtained based on the number of online devices and the SOH value, and a first difference between the SOH value and the average SOH value is obtained; the average SOC value is obtained based on the number of online devices and the SOC value, and a second difference between the SOC value and the average SOC value is obtained. The target power value of each energy storage cabinet is calculated based on the target total active power, the number of online units, the average power value, the first difference, the second difference, the preset SOH threshold, the preset SOC threshold, and the preset allocation coefficient.

2. The energy storage control method according to claim 1, characterized in that, The preset SOH threshold includes a first SOH threshold and a second SOH threshold, wherein the first SOH threshold is less than the second SOH threshold; The preset allocation coefficient includes a first SOH allocation coefficient and a second SOH allocation coefficient, wherein the first SOH allocation coefficient is greater than the second SOH allocation coefficient.

3. The energy storage control method according to claim 2, characterized in that, The target power value of each energy storage cabinet is calculated based on the target total active power, the number of online units, the average power value, the first difference, the second difference, the preset SOH threshold, the preset SOC threshold, and the preset allocation coefficient, including: The absolute value of the second difference of the energy storage cabinet is determined to be less than or equal to the preset SOC threshold; The target power value of each energy storage cabinet is calculated based on the target total active power, the number of online units, the average power value, the first difference, the first SOH threshold, the second SOH threshold, the first SOH allocation coefficient, and the second SOH allocation coefficient.

4. The energy storage control method according to claim 3, characterized in that, The target power value of each energy storage cabinet is calculated based on the target total active power, the number of online units, the average power value, the first difference, the first SOH threshold, the second SOH threshold, the first SOH allocation coefficient, and the second SOH allocation coefficient, including: If the absolute value of the first difference of the energy storage cabinet is greater than the second SOH threshold, then the first target power value P1 of the energy storage cabinet satisfies... Where Paverage is the average power value. K1 is the first difference value of the xth energy storage cabinet, and K1 is the first SOH allocation coefficient; Alternatively, if the absolute value of the first difference of the energy storage cabinet is determined to be greater than the first SOH threshold and less than or equal to the second SOH threshold, then the second target power value P2 of the energy storage cabinet satisfies... Where K2 is the second SOH partition coefficient; Alternatively, determine that the absolute value of the first difference of the energy storage cabinet is less than or equal to the first SOH threshold, obtain the remaining target active power value based on the target total active power, all the first target power values, and all the second target power values, and perform power equalization on the energy storage cabinets that satisfy the condition that the absolute value of the first difference is less than or equal to the first SOH threshold based on the remaining target active power value.

5. The energy storage control method according to claim 2, characterized in that, The preset allocation coefficient also includes a preset SOC allocation coefficient; The absolute value of the second difference of the energy storage cabinet is determined to be greater than the preset SOC threshold. The target power value of each energy storage cabinet is calculated based on the target total active power, the number of online units, the average power value, the first difference, the second difference, the first SOH threshold, the second SOH threshold, the first SOH allocation coefficient, the second SOH allocation coefficient, and the preset SOC allocation coefficient.

6. The energy storage control method according to claim 5, characterized in that, The target power value of each energy storage cabinet is calculated based on the target total active power, the number of online units, the average power value, the first difference, the second difference, the first SOH threshold, the second SOH threshold, the first SOH allocation coefficient, the second SOH allocation coefficient, and the preset SOC allocation coefficient, including: If the absolute value of the first difference of the energy storage cabinet is greater than the second SOH threshold, then the third target power value P3 of the energy storage cabinet satisfies... Where Paverage is the average power value. Let x be the first difference value of the xth energy storage cabinet. K1 is the second difference of the xth energy storage cabinet, K1 is the first SOH allocation coefficient, and f is the preset SOC allocation coefficient; Alternatively, if the absolute value of the first difference of the energy storage cabinet is determined to be greater than the first SOH threshold and less than or equal to the second SOH threshold, then the fourth target power value P4 of the energy storage cabinet satisfies... Where K2 is the second SOH partition coefficient; Alternatively, if the absolute value of the first difference of the energy storage cabinet is determined to be less than or equal to the first SOH threshold, then the fifth target power value P5 of the energy storage cabinet satisfies... .

7. The energy storage control method according to any one of claims 1-6, characterized in that, The preset allocation coefficient also includes the preset SOH power adjustment hysteresis value and the preset SOC power adjustment hysteresis value; Obtain a third difference between the first SOH threshold and the hysteresis value of the preset SOH power adjustment, a fourth difference between the second SOH threshold and the hysteresis value of the preset SOH power adjustment, and a fifth difference between the preset SOC threshold and the hysteresis value of the preset SOC power adjustment.

8. The energy storage control method according to claim 7, characterized in that, Once the operating time of the energy storage system reaches a preset time threshold, the first difference and the second difference of the energy storage cabinet are reacquired. The target power value of the energy storage cabinet is adjusted according to the first difference, the third difference, and / or the fourth difference, or the target power value of the energy storage cabinet is adjusted according to the second difference and the fifth difference.

9. An energy storage system, characterized in that, include: A transformer, wherein the transformer is mounted on an AC busbar; A gate meter, which is connected to the AC bus; A main energy storage cabinet is connected to the AC bus and the gate meter respectively, and the main energy storage cabinet is used to execute the energy storage control method according to any one of claims 1-8; At least one slave energy storage cabinet is connected to the AC bus, the gate meter and the main energy storage cabinet respectively.

10. The energy storage system according to claim 9, characterized in that, If the main energy storage cabinet is determined to be offline, at least one of the slave energy storage cabinets shall serve as the new main energy storage cabinet.

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