An energy storage system, its SOC calibration method, and a computer storage medium.

Abstract

This invention discloses an energy storage system, its SOC calibration method, and a computer storage medium. The energy storage system includes a battery module, an energy storage converter, and a transformer. The DC side of the energy storage converter is electrically connected to the battery module, the AC side of the energy storage converter is electrically connected to the primary side of the transformer, and the secondary side of the transformer is electrically connected to electrical equipment or a city power grid. The SOC calibration method for the energy storage system includes: acquiring the DC SOC of the energy storage converter's DC side and the AC SOC of the transformer's secondary side in real time; determining the current SOC difference based on the current DC SOC and the current AC SOC; and determining the current available SOC of the energy storage system based on the current DC SOC and the current AC SOC when the current SOC difference is greater than a preset difference. The technical solution of this invention can calibrate the SOC of the energy storage system, improving the estimation accuracy of the available SOC of the energy storage system.

Description

Technical Field

[0001] This invention relates to the field of electronic power technology, and in particular to an energy storage system, its SOC calibration method, and a computer storage medium. Background Technology

[0002] An energy storage system is a device that can store electrical energy and release it when needed. It is often used to solve the problem of peak shaving and valley filling in conventional power generation. It is a key facility for ensuring grid stability, adapting to the development of renewable energy, and improving energy efficiency.

[0003] Currently, energy management and power dispatch of energy storage systems are mainly determined based on the remaining power (State of Charge, SOC) provided by the battery management module in the battery module. The DC signal of the battery module is converted into an AC signal by the corresponding signal conversion module and then provided to the electrical equipment or connected to the urban power grid. However, in the process of converting DC signal into AC signal, the energy conversion from DC side to AC side is affected by the internal circuits, devices and conversion efficiency of the signal conversion module. This results in a loss in energy conversion from DC side to AC side, causing the SOC provided by the battery management module to deviate from the actual SOC that can be provided to the electrical equipment or connected to the urban power grid, thus affecting the dispatch accuracy of the energy storage system. Summary of the Invention

[0004] This invention provides an energy storage system, its SOC calibration method, and a computer storage medium to calibrate the SOC of the energy storage system and improve the estimation accuracy of the available SOC of the energy storage system.

[0005] In a first aspect, the present invention provides a SOC calibration method for an energy storage system, the energy storage system comprising a battery module, an energy storage converter, and a transformer, wherein the DC side of the energy storage converter is electrically connected to the battery module, the AC side of the energy storage converter is electrically connected to the primary side of the transformer, and the secondary side of the transformer is electrically connected to electrical equipment or a city power grid, and the SOC calibration method for the energy storage system includes:

[0006] The DC SOC of the energy storage converter and the AC SOC of the secondary side of the transformer are acquired in real time.

[0007] Determine the current SOC difference based on the current DC SOC and the current AC SOC;

[0008] When the current SOC difference is greater than a preset difference, the current available SOC of the energy storage system is determined based on the current DC SOC and the current AC SOC.

[0009] Optionally, the current available SOC of the energy storage system is determined based on the current DC SOC and the current AC SOC, including:

[0010] Obtain the current operating status of the energy storage system;

[0011] Based on the current operating conditions, determine the current calibration coefficient;

[0012] The current available SOC of the energy storage system is determined based on the current calibration coefficient, the current DC SOC, and the current AC SOC.

[0013] Optionally, the current available SOC of the energy storage system is determined based on the current calibration coefficient, the current DC SOC, and the current AC SOC, including:

[0014] Based on the current calibration coefficient, the current DC calibration coefficient and the current AC calibration coefficient are determined respectively; wherein, the sum of the current DC calibration coefficient and the current AC calibration coefficient is 1, and the current DC calibration coefficient is equal to the current calibration coefficient;

[0015] The current DC SOC contribution is determined based on the current DC calibration coefficient and the current DC SOC.

[0016] The current AC SOC contribution is determined based on the current AC calibration coefficient and the current AC SOC.

[0017] The current available SOC of the energy storage system is determined based on the current DC SOC contribution and the current AC SOC contribution.

[0018] Optionally, based on the current operating conditions, the current calibration coefficient is determined, including:

[0019] Obtain the mapping relationship between operating conditions and operating condition coefficients, as well as the mapping relationship between operating conditions and credibility.

[0020] Based on the current operating condition, the operating condition coefficient corresponding to the current operating condition in the operating condition mapping relationship is determined as the current operating condition coefficient;

[0021] Based on the current operating condition, the credibility corresponding to the current operating condition in the credibility mapping relationship is determined as the current credibility.

[0022] The current calibration coefficient is determined based on the current confidence level and the current operating condition coefficient.

[0023] Optionally, the SOC calibration method for energy storage systems also includes:

[0024] The DC capacity value of the DC side of the energy storage converter and the AC capacity value of the secondary side of the transformer are obtained in real time.

[0025] Determine the correction value for the current operating condition coefficient based on the current DC capacity value and the current AC capacity value;

[0026] Based on the current operating condition and the current operating condition coefficient correction value, the operating condition coefficient corresponding to the current operating condition in the operating condition mapping relationship is corrected.

[0027] Optionally, the SOC calibration method for energy storage systems also includes:

[0028] When the current SOC difference is less than or equal to the preset difference, the current DC SOC is determined as the current available SOC of the energy storage system.

[0029] Optionally, the AC SOC of the secondary side of the transformer can be acquired in real time, including:

[0030] The charging and discharging time of the energy storage system, the AC power on the secondary side of the transformer, the DC capacity value on the DC side of the energy storage converter, and the operating conditions are acquired in real time.

[0031] Determine the current operating condition coefficient of the energy storage system based on the current operating conditions;

[0032] The AC SOC of the transformer secondary side is determined based on the current operating condition coefficient, current charging and discharging time, current AC power, and current DC capacity value.

[0033] Optionally, the SOC calibration method for energy storage systems also includes:

[0034] The charging and discharging state of the battery module is controlled based on the current available SOC.

[0035] In a second aspect, the present invention provides an energy storage system, comprising: a battery module, an energy storage converter, a transformer, a DC signal sensor, an AC signal sensor, and a calibration controller;

[0036] The battery module is equipped with a battery management module; the charging and discharging terminals of the battery module are electrically connected to the DC side of the energy storage converter.

[0037] The DC signal sensor is used to acquire the DC signal on the DC side of the energy storage converter;

[0038] The AC side of the energy storage converter is electrically connected to the primary side of the transformer;

[0039] The secondary side of the transformer is electrically connected to the electrical equipment or the urban power grid;

[0040] The AC signal sensor is used to acquire the AC signal on the secondary side of the transformer;

[0041] The calibration controller is connected to the DC signal sensor, the AC signal sensor, and the battery management module of the battery module, respectively; the calibration controller is used to execute the SOC calibration method of the energy storage system according to the DC signal and the AC signal.

[0042] Thirdly, the present invention provides a computer storage medium storing computer instructions, which are used to cause a processor to execute the SOC calibration method of the energy storage system.

[0043] The technical solution of this invention acquires the DC SOC on the DC side of the energy storage converter and the AC SOC on the secondary side of the transformer in real time. Based on the current DC SOC and the current AC SOC, the difference between the two current SOCs is determined. When the difference between the two current SOCs is greater than a preset difference, it can be determined that there is a large deviation between the current DC SOC and the current AC SOC. At this time, the current available SOC of the energy storage system can be determined based on the current DC SOC and the current AC SOC. Thus, the SOC of the energy storage system can be calibrated based on the current available SOC, improving the SOC estimation accuracy of the energy storage system. This allows for accurate control of the charging and discharging state of the battery modules in the energy storage system based on the SOC with higher estimation accuracy, thereby improving the service life and efficiency of the battery modules. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of an energy storage system provided in an embodiment of the present invention;

[0045] Figure 2 This is a flowchart illustrating a SOC calibration method for an energy storage system provided in Embodiment 2 of the present invention;

[0046] Figure 3 This is a flowchart illustrating a SOC calibration method for an energy storage system provided in Embodiment 3 of the present invention;

[0047] Figure 4 This is a schematic flowchart of a SOC calibration method for an energy storage system provided in Embodiment 4 of the present invention;

[0048] Figure 5 This is a schematic diagram of the structure of a SOC calibration device for an energy storage system provided in an embodiment of the present invention. Detailed Implementation

[0049] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0050] The terminology used in the embodiments of this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. It should be noted that directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when referring to an element being formed "on" or "below" another element, it can be formed not only directly on or below the other element, but also indirectly on or below it through intermediate elements. The terms "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0051] The term "comprising" and its variations as used in this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0052] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish the corresponding contents and are not used to limit the order or interdependence.

[0053] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0054] Example 1

[0055] Figure 1 This is a schematic diagram of the structure of an energy storage system provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the energy storage system includes: a battery module 10, an energy storage converter 20, a transformer 30, a DC signal sensor 40, an AC signal sensor 50, and a calibration controller 60; the battery module 10 is equipped with a battery management module (not shown in the figure); the charging and discharging terminals of the battery module 10 are electrically connected to the DC side of the energy storage converter 20; the DC signal sensor 40 is used to acquire the DC signal of the DC side of the energy storage converter 20; the AC side of the energy storage converter 20 is electrically connected to the primary side of the transformer 30; the secondary side of the transformer 30 is electrically connected to the electrical equipment or the urban power grid 70; the AC signal sensor 50 is used to acquire the AC signal of the secondary side of the transformer 30; the calibration controller 60 is connected to the DC signal sensor 40, the AC signal sensor 50, and the battery management module of the battery module 10 respectively; the calibration controller 60 is used to execute the SOC calibration method of the energy storage system provided in any embodiment of the present invention based on the DC signal and the AC signal.

[0056] The battery module 10 may include multiple battery cells connected in series and / or parallel. The battery module 10 may also include a battery management module, which can monitor parameters such as voltage, current, temperature, and remaining charge of each battery cell in the battery module 10 in real time. The charging and discharging terminals of the battery module 10 are electrically connected to the DC side of the energy storage converter 20, allowing the energy storage converter 20 to convert the DC signal provided by the battery module 10 into an AC signal when the battery module 10 is discharging, and to convert the AC signal into a DC signal when the battery module 10 is charging. The AC side of the energy storage converter 20 is electrically connected to the primary side of the transformer 30, and the secondary side of the transformer 30 is electrically connected to the electrical equipment or the urban power grid 70. By setting the turns ratio of the primary and secondary sides of the transformer 30, voltage conversion of the AC signal can be achieved, ensuring that the converted AC signal meets the power requirements of the electrical equipment.

[0057] A DC signal sensor 40 may also be installed on the DC side of the energy storage converter 20. This DC signal sensor 40 can acquire the DC signal on the DC side of the energy storage converter 20, which may include DC voltage, DC current, DC side impedance, etc. An AC signal sensor 50 may also be installed on the secondary side of the transformer 30. This AC signal sensor 50 can acquire the AC signal on the secondary side of the transformer 30, which may include AC voltage, AC frequency, AC current, AC side impedance, etc.

[0058] The energy storage system also includes a calibration controller 60, which is connected to the DC signal sensor 40, the AC signal sensor 50 and the battery management module of the battery module 10. The connection method can be a communication protocol connection or an electrical connection through corresponding signal transmission wires. The specific connection method can be designed according to actual needs, and the embodiments of the present invention do not impose specific limitations on it.

[0059] It is understandable that when the battery module 10 is discharging, during the process of transmitting the DC signal from the charging and discharging terminal of the battery module 10 to the secondary side of the transformer 30, due to the influence of the internal circuitry of the energy storage converter 20 and the transformer 30, there will be a certain transmission loss of the signal. This will cause the AC signal output from the secondary side of the transformer 30 to differ from the DC signal input to the charging and discharging terminal of the battery module 10, which in turn will cause a deviation between the AC SOC and the DC SOC. Therefore, it is necessary to calibrate the deviation between the AC SOC and the DC SOC. The calibration controller 60 can obtain the DC signal from the DC side of the energy storage converter 20 through the DC signal sensor 40 and determine the DC SOC based on the DC signal, or directly obtain the SOC of the battery module 10 as the DC SOC through the battery management module. At the same time, the calibration controller 60 can also obtain the AC signal from the secondary side of the transformer 30 through the AC signal sensor 50 to determine the AC SOC based on the AC signal. After the calibration controller 60 determines the DC SOC and AC SOC, it can determine the SOC difference based on the DC SOC and AC SOC. When the SOC difference is large, it can be determined that the difference between the DC SOC and AC SOC is large and the overall SOC of the energy storage system needs to be calibrated. At this time, the available SOC of the energy storage system can be determined based on the DC SOC and AC SOC, and the available SOC can be used to calibrate the SOC of the energy storage system.

[0060] This embodiment uses an energy storage converter to convert the DC signal provided by the battery module or the AC signal provided by the transformer into DC and AC signals, and uses the transformer to convert the AC signal into voltage. This allows the converted AC signal to meet the power demand of electrical equipment or the peak-shaving and frequency regulation requirements of the urban power grid, or to meet the charging requirements of the battery module. Simultaneously, by using a DC signal sensor to acquire the DC signal from the energy storage converter's DC side and an AC signal sensor to acquire the AC signal from the transformer's secondary side, the calibration controller determines the DC SOC based on the SOC provided by the battery management module of the battery module or the DC signal acquired by the DC signal sensor, and the AC SOC based on the AC signal acquired by the AC signal sensor. Based on the DC and AC SOCs, the corresponding available SOC is determined. This available SOC is then used to calibrate the SOC of the energy storage system, improving the accuracy of available SOC estimation. This improves the accuracy of controlling the charging and discharging state of the battery module, thereby increasing the lifespan and efficiency of the energy storage system.

[0061] It is understood that the calibration controller of the energy storage system provided in the embodiments of the present invention can be used to execute the SOC calibration method of the energy storage system provided in any embodiment of the present invention. Therefore, the calibration controller of the energy storage system has the relevant functional structure for executing the SOC calibration method of the energy storage system provided in any embodiment of the present invention, and can achieve the same beneficial effect as the SOC calibration method of the energy storage system provided in the embodiments of the present invention. For details, please refer to the following description.

[0062] Example 2

[0063] Figure 2 This is a flowchart illustrating a State of Charge (SOC) calibration method for an energy storage system according to Embodiment 2 of the present invention. This embodiment can be used to calibrate the SOC of an energy storage system. The method can be executed by an SOC calibration device for the energy storage system. This SOC calibration device can be implemented in software and / or hardware, and is generally integrated into the calibration controller of the energy storage system provided in this embodiment of the present invention. Figure 2 As shown, the SOC calibration method for energy storage systems includes:

[0064] S110: Real-time acquisition of DC SOC on the DC side of the energy storage converter and AC SOC on the secondary side of the transformer.

[0065] The DC SOC of the energy storage converter refers to the remaining power of the battery module or the power that the battery module can provide to the energy storage converter. The AC SOC of the transformer secondary side refers to the power that the transformer can output to electrical equipment or the urban power grid. The DC SOC of the energy storage converter can be directly obtained by the battery management module installed in the battery module, or determined by obtaining the DC signal from the DC signal sensor installed on the DC side of the energy storage converter. The AC SOC of the transformer secondary side can be determined by obtaining the AC signal from the AC signal sensor installed on the secondary side of the transformer.

[0066] In an optional embodiment, real-time acquisition of the AC SOC of the secondary side of the transformer may include: real-time acquisition of the charging and discharging time of the energy storage system, the AC power of the secondary side of the transformer, the DC capacity value of the DC side of the energy storage converter, and the operating conditions; determining the current operating condition coefficient of the energy storage system based on the current operating conditions; and determining the AC SOC of the secondary side of the transformer based on the current operating condition coefficient, the current charging and discharging time, the current AC power, and the current DC capacity value.

[0067] The charging and discharging time of the energy storage system can be understood as the charging or discharging time of the energy storage system. Charging time is the duration the energy storage system is in a charging state, and discharging time is the duration the energy storage system is in a discharging state. The charging and discharging time of the energy storage system can be obtained through the battery management module installed in the battery module. The AC power on the secondary side of the transformer can be determined based on the AC signal acquired by the AC signal sensor installed on the secondary side of the transformer. This AC power can be the output power when the secondary side of the transformer provides an AC signal to the electrical equipment or the urban power grid, or it can be the input power when the secondary side of the transformer receives an AC signal from the urban power grid or power supply equipment. The DC capacity value on the DC side of the energy storage converter can be determined based on the DC signal acquired by the DC signal sensor installed on the DC side of the energy storage converter. The operating conditions of the energy storage system can include the load rate, temperature, and charging / discharging status of the battery module. The load rate can be understood as the load change of the energy storage system, which can be determined through the output voltage and output current of the energy storage system. The temperature of the energy storage system can be obtained through a temperature sensor installed in the energy storage system. The charging / discharging status of the battery module can be obtained through the battery management module.

[0068] There can be a certain mapping relationship between operating conditions and operating condition coefficients. This mapping relationship can be a mapping table or a mapping formula. By testing the operating condition coefficients of the energy storage system under different operating conditions before it leaves the factory, the mapping relationship between operating conditions and operating condition coefficients can be determined. For example, when the operating conditions include the load rate of the energy storage system, the temperature of the energy storage system, and the charging and discharging state of the battery module, the operating condition coefficients corresponding to different load rates and different temperatures can be detected in the charging state to form a table of correspondence between load rate and temperature and operating condition coefficients in the charging state. This table is used as the mapping relationship between operating conditions and operating condition coefficients in the charging state. Similarly, the operating condition coefficients corresponding to different load rates and different temperatures can be detected in the discharging state to form a table of correspondence between load rate and temperature and operating condition coefficients in the discharging state. This table is used as the mapping relationship between operating conditions and operating condition coefficients in the discharging state. Thus, after determining the current operating conditions of the energy storage system, namely the current charging and discharging state, current load rate, and current temperature, the corresponding operating condition coefficients can be determined by looking up a table.

[0069] There can also be a certain mapping relationship between the current operating condition coefficient, current charging and discharging time, current AC power, and current DC capacity value and the AC SOC. This mapping relationship can also be a mapping formula or a mapping table. After determining the current operating condition coefficient, current charging and discharging time, current AC power, and current DC capacity value, the AC SOC of the transformer secondary side can be determined by using the mapping formula or by looking up the mapping table.

[0070] In an optional embodiment, during charging of the energy storage system, the AC SOC on the secondary side of the transformer can be determined based on a first calculation formula; the first calculation formula is:

[0071] ;

[0072] When the energy storage system discharges, the AC SOC on the secondary side of the transformer is determined based on the second calculation formula, which is:

[0073] ;

[0074] Among them, SOC ac For the AC SOC of the secondary side of the transformer, P ac Q represents the AC power on the secondary side of the transformer. dc Let K1 be the DC capacity value of the DC side of the energy storage converter, K1 be the operating condition coefficient, and t be the charging and discharging time of the energy storage system. When the energy storage system is in the charging state, the current operating condition coefficient, the current charging time, the current AC power and the current DC capacity value of the AC signal received by the secondary side of the transformer can be determined accordingly. Substituting the current operating condition coefficient, the current charging time, the current AC power and the current DC capacity value into the first calculation formula above, the AC SOC of the secondary side of the transformer in the charging state can be calculated accordingly. When the energy storage is in the discharging state, the current operating condition coefficient, the current discharging time, the current AC power and the current DC capacity value of the AC signal output by the secondary side of the transformer can be determined accordingly. Substituting the current operating condition coefficient, the current discharging time, the current AC power and the current DC capacity value into the second calculation formula above, the AC SOC of the secondary side of the transformer in the discharging state can be calculated accordingly.

[0075] S120. Determine the current SOC difference based on the current DC SOC and the current AC SOC.

[0076] Specifically, the current SOC difference can be the absolute value of the difference between the current DC SOC and the current AC SOC. The SOC difference reflects the degree of difference between the DC SOC and AC SOC of the energy storage system, that is, the difference between the amount of electricity the energy storage system can output to electrical devices or the city grid and the remaining electricity in the battery modules of the energy storage system. A larger current SOC difference indicates a greater difference between the remaining electricity in the battery modules and the amount of electricity the energy storage system can provide to electrical devices or the city grid. This means the DC signal provided by the battery modules experiences greater losses during signal conversion and transmission, requiring SOC calibration of the energy storage system. Conversely, a smaller current SOC difference indicates a smaller difference between the remaining electricity in the battery modules and the amount of electricity the energy storage system can provide to electrical devices or the city grid. This means the remaining electricity in the battery modules can be fully or mostly provided to electrical devices or the city grid, and the DC signal provided by the battery modules experiences less loss during signal conversion and transmission, eliminating the need for SOC calibration of the energy storage system.

[0077] S130. When the current SOC difference is greater than the preset difference, determine the current available SOC of the energy storage system based on the current DC SOC and the current AC SOC.

[0078] The preset difference can be understood as the limit difference between DC SOC and AC SOC, or a value less than the limit difference, that ensures the normal operation of electrical equipment or peak shaving and frequency regulation of the urban power grid. The specific value of the preset difference can be designed according to actual needs, and this embodiment of the invention does not impose a specific limitation on it. In an optional embodiment, the preset difference can be 3%.

[0079] Specifically, when the current SOC difference is greater than the preset difference, it indicates that the signal loss during transmission is significant, and the current DC SOC or current AC SOC may be inaccurate. In this case, the current available SOC of the energy storage system can be calculated based on the contribution of the current DC SOC and current AC SOC to the SOC of the energy storage system. This means that the energy storage system can provide the maximum amount of electricity to the electrical equipment, enabling the energy storage system to control the working state of the battery module based on the current available SOC, thereby improving the lifespan and efficiency of the energy storage system.

[0080] This embodiment acquires the DC SOC on the DC side of the energy storage converter and the AC SOC on the secondary side of the transformer in real time. Based on the current DC SOC and the current AC SOC, it determines the current SOC difference. When the current SOC difference is greater than a preset difference, it can be determined that there is a large deviation between the current DC SOC and the current AC SOC. At this time, the current available SOC of the energy storage system can be determined based on the current DC SOC and the current AC SOC. Thus, the SOC of the energy storage system can be calibrated based on the current available SOC, improving the SOC estimation accuracy of the energy storage system. This allows for accurate control of the charging and discharging state of the battery modules in the energy storage system based on the SOC with higher estimation accuracy, thereby improving the service life and efficiency of the battery modules.

[0081] Example 3

[0082] Figure 3 This is a flowchart illustrating a State of Charge (SOC) calibration method for an energy storage system according to Embodiment 3 of the present invention. Based on the above embodiments, this embodiment provides a detailed explanation of the method for determining the current available SOC of the energy storage system, such as... Figure 3 As shown, the SOC calibration method for this energy storage system includes:

[0083] S210: Real-time acquisition of DC SOC on the DC side of the energy storage converter and AC SOC on the secondary side of the transformer.

[0084] S220. Determine the current SOC difference based on the current DC SOC and the current AC SOC.

[0085] S230: Obtain the current operating status of the energy storage system.

[0086] The operating conditions of the energy storage system can include the system's load rate, temperature, battery module charge / discharge status, battery module charge / discharge time, and battery module state time. The system's load rate can be determined by the AC voltage and current on the secondary side of the transformer; the system's temperature can be obtained by a temperature sensor installed within the system; the battery module's charge / discharge status, charge / discharge time, and state time can all be obtained by the battery management module installed within the battery module; the battery module's charge / discharge status can include charging and discharging states; the battery module's charging time can include charging time (i.e., the continuous charging time of the battery module) and discharging time (i.e., the continuous discharging time of the battery module); and the battery module's state time can include the duration the battery module maintains a certain SOC value.

[0087] S240. Determine the current calibration coefficient based on the current operating conditions.

[0088] Specifically, there can be a certain mapping relationship between the current calibration coefficient and the current operating condition. This mapping relationship can be a formula or a table. Therefore, after determining the current operating condition, the current load rate, current temperature, current charging / discharging state, current charging / discharging time, and current state time can be determined accordingly. Based on parameters such as the current load rate, current temperature, current charging / discharging state, current charging / discharging time, and current state time, the current calibration coefficient can be determined by formula calculation or table lookup.

[0089] In an optional embodiment, determining the current calibration coefficient based on the current operating condition includes: obtaining the operating condition mapping relationship between the operating condition and the operating condition coefficient, and the credibility mapping relationship between the operating condition and the credibility; determining the operating condition coefficient corresponding to the current operating condition in the operating condition mapping relationship as the current operating condition coefficient; determining the credibility corresponding to the current operating condition in the credibility mapping relationship as the current credibility based on the current operating condition; and determining the current calibration coefficient based on the current credibility and the current operating condition coefficient.

[0090] The mapping relationship between operating conditions and operating condition coefficients can be a mapping table or a mapping formula. By testing the operating condition coefficients of the energy storage system under different operating conditions before it leaves the factory, the mapping relationship between operating conditions and operating condition coefficients is determined. For example, when the operating conditions include the load rate of the energy storage system, the temperature of the energy storage system, and the charging and discharging state of the battery module, the operating condition coefficients corresponding to different load rates and different temperatures can be detected in the charging state to form a table of correspondence between load rate and temperature and operating condition coefficients in the charging state. This table is used as the mapping relationship between operating conditions and operating condition coefficients in the charging state. Similarly, the operating condition coefficients corresponding to different load rates and different temperatures can be detected in the discharging state to form a table of correspondence between load rate and temperature and operating condition coefficients in the discharging state. This table is used as the mapping relationship between operating conditions and operating condition coefficients in the discharging state. Thus, after determining the current operating conditions of the energy storage system, namely the current charging and discharging state, current load rate, and current temperature, the corresponding operating condition coefficients can be determined by looking up a table.

[0091] It is understandable that the operating condition mapping relationship between the operating conditions and the operating condition coefficients determined through testing before the energy storage system leaves the factory is usually the operating condition mapping relationship under the ideal operating conditions of the energy storage system. However, during the actual operation of the energy storage system, due to the environment in which the energy storage system is located, the continuous degradation and aging of the battery modules in the energy storage system, etc., there is a certain deviation between the actual operating conditions and the ideal operating conditions. This causes the operating condition coefficients determined by looking up the table based on the actual operating conditions to have a certain deviation. At this time, the operating condition coefficients corresponding to the current operating conditions can be calibrated according to the parameters under the current operating conditions.

[0092] In an optional embodiment, the calibration method for the operating condition coefficient may include: acquiring in real time the DC capacity value of the DC side of the energy storage converter and the AC capacity value of the secondary side of the transformer; determining the current operating condition coefficient correction value based on the current DC capacity value and the current AC capacity value; and correcting the operating condition coefficient corresponding to the current operating condition in the operating condition mapping relationship based on the current operating condition and the current operating condition coefficient correction value.

[0093] The DC capacity value of the energy storage converter on the DC side can be determined based on the DC signal obtained by the DC signal sensor installed on the DC side of the energy storage converter, and the AC capacity value of the transformer secondary side can be determined based on the AC signal obtained by the AC signal sensor installed on the transformer secondary side.

[0094] Specifically, the current operating condition coefficient correction value can be positively or negatively correlated with the current DC capacity value and the current AC capacity value. After obtaining the current DC capacity value and the current AC capacity value, the current operating condition coefficient correction value can be calculated accordingly.

[0095] In an exemplary embodiment, when the energy storage system is in a charging state, the correction value of the operating condition factor can be calculated based on a third calculation formula, which is:

[0096] ;

[0097] When the energy storage system is in a discharging state, the correction value of the operating condition factor can be calculated based on the fourth calculation formula, which is:

[0098] ;

[0099] Where K1´ is the working condition coefficient correction value, Q dc Q is the current DC capacity value. ac The current AC capacity value is used. When the energy storage system is charging, the current DC capacity value and the current AC capacity value can be substituted into the third calculation formula mentioned above to calculate the current operating condition coefficient correction value. When the energy storage system is discharging, the current DC capacity value and the current AC capacity value can be substituted into the fourth calculation formula mentioned above to calculate the current operating condition coefficient correction value. After calculating the current operating condition coefficient correction value, the corresponding operating condition coefficient in the original operating condition mapping relationship can be found, and the current operating condition coefficient correction value can replace the corresponding operating condition coefficient in the original operating condition mapping relationship. This improves the accuracy of the determined operating condition coefficient in subsequent calculations, thereby improving the estimation accuracy of available SOC.

[0100] The reliability mapping relationship between operating conditions and reliability can also be represented by a mapping table or a mapping formula. This mapping relationship is determined by testing the reliability of the energy storage system under different operating conditions before it leaves the factory. For example, when the operating conditions include the full-charge interval duration (the interval between the last time the energy storage system reaches its upper or lower SOC limit and the current time), the reliability corresponding to different full-charge interval durations can be tested, and a table showing the relationship between different full-charge interval durations and reliability can be created as the reliability mapping relationship. After determining the current full-charge interval duration, the reliability corresponding to the current full-charge interval duration can be determined by looking up the table in the reliability mapping relationship as the current reliability of the energy storage system. In an optional embodiment, the relationship between the full-charge interval duration and reliability can be inversely correlated; that is, the longer the current full-charge interval duration, the lower the current reliability of the energy storage system; the shorter the current full-charge interval duration, the higher the current reliability of the energy storage system. In this context, the State of Charge (SOC) of the energy storage system can be understood as the usable SOC after calibration. In some embodiments, the SOC of the energy storage system can also be understood as the SOC recorded by the battery management module in the battery module. The specific design can be tailored to actual needs, and this embodiment of the invention does not impose specific limitations on this. For example, the upper limit of the SOC can be 100%, and the lower limit can be 0%. In an exemplary embodiment, when the interval between 100% and 0% SOC of the energy storage system is one month (i.e., the current full-charge interval is one month), the current confidence level K2 can be 0.5; when the interval between 100% and 0% SOC of the energy storage system is two months (i.e., the current full-charge interval is two months), the current confidence level K2 can be 0.4.

[0101] It is understood that the above is merely an illustrative description of the relationship between operating conditions and reliability, and other correspondences may exist between operating conditions and reliability in embodiments of the present invention. In an optional embodiment, when the operating conditions include load rate, the reliability of the energy storage system under different load rates can be tested before leaving the factory to form a correspondence table between load rate and reliability. This correspondence table is used as a reliability mapping relationship, so that after obtaining the current load rate, the reliability of the energy storage system corresponding to the current load rate can be determined by looking up the table in the reliability mapping relationship. In an exemplary embodiment, the relationship between load rate and reliability can be negatively correlated, that is, the lower the load rate, the higher the reliability. For example, when the energy storage system is operating under a low load rate condition, the current reliability value can be 0.95.

[0102] Furthermore, after determining the current confidence level and the current operating condition coefficient, the current calibration coefficient corresponding to the current confidence level and the current operating condition coefficient can be determined based on the contribution of the confidence level and the operating condition coefficient to the calibration coefficient. For example, the current calibration coefficient can be the product of the current confidence level and the current operating condition coefficient.

[0103] S250. Determine the current available SOC of the energy storage system based on the current calibration coefficient, the current DC SOC, and the current AC SOC.

[0104] Specifically, there can be a certain mapping relationship between the current available SOC and the current calibration coefficient, the current DC SOC, and the current AC SOC. This mapping relationship can be a formula or a table. Therefore, after determining the current calibration coefficient, the current DC SOC, and the current AC SOC, the current available SOC of the energy storage system can be determined by formula calculation or table lookup.

[0105] In an optional embodiment, determining the current available SOC of the energy storage system based on the current calibration coefficient, the current DC SOC, and the current AC SOC may include: determining the current DC calibration coefficient and the current AC calibration coefficient based on the current calibration coefficient; determining the current DC SOC contribution based on the current DC calibration coefficient and the current DC SOC; determining the current AC SOC contribution based on the current AC calibration coefficient and the current AC SOC; and determining the current available SOC of the energy storage system based on the current DC SOC contribution and the current AC SOC contribution.

[0106] Wherein, the sum of the current DC calibration coefficient and the current AC calibration coefficient is 1, and the current DC calibration coefficient is equal to the current calibration coefficient. That is, when the current calibration coefficient is α, the current DC calibration coefficient is α, and the current AC calibration coefficient is 1-α.

[0107] Specifically, after determining the current calibration coefficient α, the current DC calibration coefficient α and the current AC calibration coefficient 1-α can be determined accordingly. The current DC calibration coefficient represents the contribution ratio of the current DC SOC to the current available SOC. Based on the product between the current DC SOC and the current DC calibration coefficient α, the contribution amount of the current DC SOC can be determined accordingly. The current AC calibration coefficient represents the contribution ratio of the current AC SOC to the current available SOC. Based on the product between the current AC SOC and the current AC calibration coefficient 1-α, the contribution amount of the current AC SOC can be determined accordingly. After determining the contribution amounts of the current DC SOC and the current AC SOC, their sum can be calculated as the current available SOC.

[0108] In an exemplary embodiment, based on the current DC calibration coefficient, the current DC SOC, the current AC calibration coefficient, and the current AC SOC, the current available SOC of the energy storage system can be determined using a fifth calculation formula, which is:

[0109] ;

[0110] Among them, SOC out The available State of Charge (SOC) for the energy storage system, α is the DC calibration factor, 1-α is the AC calibration factor, and SOC dc DC SOC ac The current DC calibration coefficient, current DC SOC, current AC calibration coefficient, and current AC SOC are determined. These values ​​can be substituted into the fifth calculation formula above to calculate the current available SOC of the energy storage system. That is, the sum of the current DC SOC contribution and the current AC SOC contribution is the current available SOC of the energy storage system.

[0111] In an exemplary embodiment, after obtaining the current operating condition of the energy storage system, the current operating condition coefficient K1 is determined to be 0.95 and the current confidence level K2 is determined to be 0.4 by looking up a table. At this time, the current DC calibration coefficient α is calculated as 0.95 × 0.4 = 0.38; if the current DC SOC value is SOC dc The current SOC value is 60%. ac If it is 55%, then the current available SOC of the energy storage system can be calculated: SOC out =0.38×60%+(1-0.38)×55%=56.9%; where, SOC out This is the currently available SOC.

[0112] This embodiment obtains the current operating conditions of the energy storage system, determines the current calibration coefficient based on the current operating conditions, and determines the contribution of the DC SOC and AC SOC to the available SOC based on the current calibration coefficient, the current DC SOC, and the current AC SOC, respectively. Based on the contribution of the two, the current available SOC of the energy storage system is determined, which effectively improves the estimation accuracy of the available SOC.

[0113] Example 4

[0114] Figure 4 This is a flowchart illustrating a State of Charge (SOC) calibration method for an energy storage system according to Embodiment 4 of the present invention. Based on the above embodiments, this embodiment provides a detailed explanation of the method for determining the currently available SOC and the method for controlling the charge and discharge state of the battery module, such as... Figure 4 As shown, the SOC calibration method for this energy storage system includes:

[0115] S310: Real-time acquisition of DC SOC on the DC side of the energy storage converter and AC SOC on the secondary side of the transformer.

[0116] S320. Determine the current SOC difference based on the current DC SOC and the current AC SOC.

[0117] S330. When the current SOC difference is greater than the preset difference, determine the current available SOC of the energy storage system based on the current DC SOC and the current AC SOC.

[0118] S340. When the current SOC difference is less than or equal to the preset difference, the current DC SOC is determined as the current available SOC of the energy storage system.

[0119] It is understandable that when the current SOC difference is less than or equal to the preset difference, it means that the signal loss during transmission is small. Therefore, it is not necessary to calibrate the current available SOC. The current DC SOC can be determined as the current available SOC of the energy storage system, which simplifies the SOC calibration process, reduces the amount of data processing, and improves the SOC calibration efficiency.

[0120] S350: Controls the charging and discharging state of the battery module based on the current available SOC.

[0121] Specifically, the current available SOC of an energy storage system can represent the maximum amount of electricity that the energy storage system can currently provide to the city power grid or electrical equipment. The current available SOC can be used to determine whether the battery module needs to continue charging or discharging, thereby allowing for corresponding control of the battery module's charging and discharging state.

[0122] In one exemplary embodiment, when multiple energy storage systems operate in parallel to participate in the frequency regulation of the urban power grid, the charging and discharging state of the battery modules of each energy storage system can be controlled according to the current available SOC of each energy storage system. This allows the battery modules of each energy storage system to be fully charged or discharged to the target SOC simultaneously, ensuring that the overall power of each energy storage system remains stable. Alternatively, when energy storage systems participate in peak shaving of the urban power grid, the amount of electricity that can be input into or output to the urban power grid can be determined according to the current available SOC of each energy storage system. This enables the battery modules of the energy storage system to provide maximum power to the urban power grid during peak hours and to store maximum power from the urban power grid during off-peak hours, thereby improving the operational economy of each energy storage system and maximizing market returns.

[0123] In another exemplary embodiment, by calibrating the State of Charge (SOC) of the energy storage system, the depth of charge and discharge and the charge / discharge power of the battery modules in the energy storage system can be controlled. For example, when the battery modules of the energy storage system are in a discharging state, if the current available SOC is low, it means that the battery modules are close to their minimum remaining capacity. Continuing to discharge will affect the lifespan of the battery modules and the stability of the output power of the energy storage system. At this time, it is necessary to control the battery modules to stop discharging, that is, to control the energy storage system to switch from a discharging state to a charging state or a shutdown state. When the battery modules of the energy storage system are charging, if the current available SOC is high, it means that the battery modules are close to their maximum remaining capacity. At this time, it is not necessary to continue charging the battery modules, and the energy storage system can be controlled to stop charging or participate in discharging. In this way, based on the current available SOC, the charge / discharge power of the battery modules can be precisely controlled, improving the lifespan and economic benefits of the energy storage system.

[0124] This embodiment simplifies the SOC calibration process, reduces data processing, and improves SOC calibration efficiency by determining the current DC SOC as the current available SOC of the energy storage system when the current SOC difference is less than or equal to a preset difference. Simultaneously, after determining the current available SOC of the energy storage system, the charging and discharging states of the battery modules can be controlled based on the current available SOC, achieving more efficient energy dispatch control, extending the service life of the energy storage system, meeting market response control requirements, maximizing revenue, and improving the operational economy of the energy storage system.

[0125] Example 5

[0126] Figure 5 This is a schematic diagram of the structure of a SOC calibration device for an energy storage system provided in an embodiment of the present invention. This device can be used to calibrate the SOC of an energy storage system. The SOC calibration device can be implemented by software and / or hardware, and is generally integrated into the calibration controller of the energy storage system provided in this embodiment of the present invention. Figure 5 As shown, the SOC calibration device for the energy storage system includes:

[0127] SOC acquisition module 510 is used to acquire the DC SOC on the DC side of the energy storage converter and the AC SOC on the secondary side of the transformer in real time.

[0128] SOC difference determination module 520 is used to determine the current SOC difference based on the current DC SOC and the current AC SOC;

[0129] The available SOC determination module 530 is used to determine the current available SOC of the energy storage system based on the current DC SOC and the current AC SOC when the current SOC difference is greater than a preset difference.

[0130] Optionally, the available SOC determination module 530 may include an operating condition acquisition unit, a calibration coefficient determination unit, and an available SOC determination unit; the operating condition acquisition unit is used to acquire the current operating condition of the energy storage system; the calibration coefficient determination unit is used to determine the current calibration coefficient based on the current operating condition; and the available SOC determination unit is used to determine the current available SOC of the energy storage system based on the current calibration coefficient, the current DC SOC, and the current AC SOC.

[0131] Optionally, the available SOC determination unit is specifically used to determine the current DC calibration coefficient and the current AC calibration coefficient based on the current calibration coefficient; determine the current DC SOC contribution based on the current DC calibration coefficient and the current DC SOC; determine the current AC SOC contribution based on the current AC calibration coefficient and the current AC SOC; and determine the current available SOC of the energy storage system based on the current DC SOC contribution and the current AC SOC contribution. The sum of the current DC calibration coefficient and the current AC calibration coefficient is 1, and the current DC calibration coefficient is equal to the current calibration coefficient.

[0132] Optionally, the calibration coefficient determination unit is specifically used to obtain the operating condition mapping relationship between operating conditions and operating condition coefficients, and the reliability mapping relationship between operating conditions and reliability; based on the current operating condition, determine the operating condition coefficient corresponding to the current operating condition in the operating condition mapping relationship as the current operating condition coefficient; based on the current operating condition, determine the reliability corresponding to the current operating condition in the reliability mapping relationship as the current reliability; and determine the current calibration coefficient based on the current reliability and the current operating condition coefficient.

[0133] Optionally, the SOC calibration device of the energy storage system may also include an operating condition coefficient correction module. The operating condition coefficient correction module is used to acquire the DC capacity value of the DC side of the energy storage converter and the AC capacity value of the secondary side of the transformer in real time; determine the current operating condition coefficient correction value based on the current DC capacity value and the current AC capacity value; and correct the operating condition coefficient corresponding to the current operating condition in the operating condition mapping relationship based on the current operating condition and the current operating condition coefficient correction value.

[0134] Optionally, the available SOC determination module 530 is also used to determine the current DC SOC as the current available SOC of the energy storage system when the current SOC difference is less than or equal to a preset difference.

[0135] Optionally, the SOC acquisition module 510 is specifically used to acquire in real time the charging and discharging time of the energy storage system, the AC power on the secondary side of the transformer, the DC capacity value on the DC side of the energy storage converter, and the operating conditions; determine the current operating condition coefficient of the energy storage system based on the current operating conditions; and determine the AC SOC on the secondary side of the transformer based on the current operating condition coefficient, the current charging and discharging time, the current AC power, and the current DC capacity value.

[0136] Optionally, the SOC calibration device for the energy storage system also includes a battery module control module, which controls the charging and discharging state of the battery module based on the current available SOC.

[0137] It is understood that, since the SOC calibration device for the energy storage system described above is an apparatus capable of executing the SOC calibration method for the energy storage system in the embodiments of the present invention, those skilled in the art can understand the specific implementation and various variations of the SOC calibration device for the energy storage system in this embodiment based on the SOC calibration method for the energy storage system described in the embodiments of the present invention. Therefore, how the SOC calibration device for the energy storage system implements the SOC calibration method for the energy storage system in the embodiments of the present invention will not be described in detail here. Any apparatus used by those skilled in the art to implement the SOC calibration method for the energy storage system in the embodiments of the present invention falls within the scope of protection of this application.

[0138] Example 6

[0139] This invention provides a computer storage medium storing computer instructions. These instructions are used to enable a processor to execute a SOC calibration method for an energy storage system, thus achieving the beneficial effects of the corresponding SOC calibration method for an energy storage system. Similarities can be found in the description above, and will not be repeated here.

[0140] In the context of this invention, a computer storage medium can be a tangible medium that may contain or store computer programs for use by or in conjunction with an instruction execution system, apparatus, or device. The computer storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof.

[0141] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for SOC calibration of an energy storage system, characterized by, The energy storage system comprises a battery module, an energy storage converter and a transformer, a direct current side of the energy storage converter is electrically connected with the battery module, an alternating current side of the energy storage converter is electrically connected with a primary side of the transformer, a secondary side of the transformer is electrically connected with a power utilization device or a city power grid, and a SOC calibration method of the energy storage system comprises: real-time acquisition of a direct current SOC of a direct current side of the energy storage converter and an alternating current SOC of a secondary side of the transformer; determination of a current SOC difference value according to a current direct current SOC and a current alternating current SOC; acquisition of a current operating condition of the energy storage system when the current SOC difference value is greater than a preset difference value; determination of a current calibration coefficient according to the current operating condition; determination of a current available SOC of the energy storage system according to the current calibration coefficient, the current direct current SOC and the current alternating current SOC; wherein the determination of the current available SOC of the energy storage system according to the current calibration coefficient, the current direct current SOC and the current alternating current SOC comprises: determination of a current direct current calibration coefficient and a current alternating current calibration coefficient according to the current calibration coefficient; wherein a sum of the current direct current calibration coefficient and the current alternating current calibration coefficient is 1, and the current direct current calibration coefficient is equal to the current calibration coefficient; determination of a current direct current SOC contribution amount according to the current direct current calibration coefficient and the current direct current SOC; determination of a current alternating current SOC contribution amount according to the current alternating current calibration coefficient and the current alternating current SOC; determination of the current available SOC of the energy storage system according to the current direct current SOC contribution amount and the current alternating current SOC contribution amount.

2. The method of calibrating the SOC of an energy storage system according to claim 1, wherein, The determination of the current calibration coefficient according to the current operating condition comprises: acquisition of an operating condition-mapping relationship of operating conditions and condition coefficients and a credibility-mapping relationship of operating conditions and credibility; determination of a current condition coefficient corresponding to the current operating condition in the operating condition-mapping relationship as the current condition coefficient according to the current operating condition; determination of a current credibility corresponding to the current operating condition in the credibility-mapping relationship as the current credibility according to the current operating condition; determination of the current calibration coefficient according to the current credibility and the current condition coefficient.

3. The method of calibrating the SOC of an energy storage system according to claim 2, wherein, Further comprising: real-time acquisition of a direct current capacity value of a direct current side of the energy storage converter and an alternating current capacity value of a secondary side of the transformer; determination of a current condition coefficient correction value according to a current direct current capacity value and a current alternating current capacity value; correction of a condition coefficient corresponding to the current operating condition in the operating condition-mapping relationship according to the current operating condition and the current condition coefficient correction value.

4. The method of calibrating the SOC of an energy storage system of claim 1, wherein, Further comprising: determination of the current direct current SOC as the current available SOC of the energy storage system when the current SOC difference value is less than or equal to the preset difference value.

5. The method of calibrating the SOC of an energy storage system of claim 1, wherein, The real-time acquisition of the alternating current SOC of the secondary side of the transformer comprises: real-time acquisition of a charge-discharge time of the energy storage system, an alternating current power of the secondary side of the transformer, a direct current capacity value of a direct current side of the energy storage converter and an operating condition; According to the current operating condition, a current operating condition coefficient of the energy storage system is determined; According to the current operating condition coefficient, current charging and discharging time, current alternating current power, and current direct current capacity value, an alternating current SOC of a secondary side of the transformer is determined.

6. The method of calibrating the SOC of an energy storage system of claim 1, wherein, Further comprising: According to the current available SOC, a charging and discharging state of the battery module is controlled.

7. An energy storage system characterized by, Comprising: a battery module, an energy storage converter, a transformer, a direct current signal sensor, an alternating current signal sensor, and a calibration controller; The battery module is provided with a battery management module; A charging and discharging end of the battery module is electrically connected with a direct current side of the energy storage converter; The direct current signal sensor is used to acquire a direct current signal of the direct current side of the energy storage converter; An alternating current side of the energy storage converter is electrically connected with a primary side of the transformer; A secondary side of the transformer is electrically connected with a power utilization device or a city power grid; The alternating current signal sensor is used to acquire an alternating current signal of the secondary side of the transformer; The calibration controller is connected with the direct current signal sensor, the alternating current signal sensor, and the battery management module of the battery module respectively; and the calibration controller is used to execute the SOC calibration method of the energy storage system according to the direct current signal and the alternating current signal.

8. A computer storage medium, characterized in that The computer storage medium stores computer instructions, and the computer instructions are used to make the processor execute the SOC calibration method of the energy storage system according to any one of claims 1-6 when executed.

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