Energy storage output method with multiple subsystems and energy storage system

Abstract

The application discloses an energy storage output method and an energy storage system with multiple subsystems. The energy storage output total power required by the energy storage system to be provided to a load is calculated. Then, the SOC proportion values of each subsystem in the energy storage system are obtained. Finally, the sub-output power of each subsystem is regulated according to the energy storage output total power and all the SOC proportion values. The multiple subsystems can meet the capacity demand of the load, and the energy scheduling of each subsystem can effectively prevent the continuous high-power operation of a certain subsystem, so that each subsystem can operate according to the actual situation, the short board effect is eliminated, the system consistency is improved, and the system has good charging and discharging efficiency.

Description

Technical Field

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

[0002] Currently, large industrial and commercial enterprises face high electricity costs and require significant energy storage capacity. To meet these demands, energy storage systems inevitably employ a parallel configuration of multiple battery cabinets. However, this parallel configuration, with its large number of cabinets, is prone to a bottleneck effect. When a problem occurs in any part of the system, the entire system will stop working, impacting the enterprise's electricity needs and resulting in poor system consistency, thus affecting the system's charging and discharging efficiency. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an energy storage output method and energy storage system with multiple subsystems, which eliminates the bottleneck effect while meeting capacity requirements and ensures that the system has good charging and discharging efficiency.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A method for energy storage output with multiple subsystems, comprising the following steps:

[0006] S1. Calculate the total energy storage output power that the energy storage system needs to provide to the load;

[0007] S2. Obtain the SOC ratio value of each subsystem in the energy storage system;

[0008] S3. Adjust the sub-output power of each subsystem according to the total energy storage output power and all the SOC ratio values.

[0009] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is as follows:

[0010] An energy storage system with multiple subsystems, including an energy management unit and two or more subsystems;

[0011] The energy management unit is communicatively connected to all the subsystems and is used to execute the above-described energy storage output method with multiple subsystems.

[0012] The beneficial effects of this invention are as follows: It provides an energy storage output method and energy storage system with multiple subsystems. First, the total energy storage output power required by the energy storage system to be provided to the load is determined. Then, the sub-output power of each subsystem is adjusted in combination with the SOC ratio value of each subsystem. Using multiple subsystems can meet the capacity requirements of the load. By scheduling the energy of each subsystem, it is possible to effectively prevent a certain subsystem from operating at high power continuously, so that each subsystem can operate according to its own actual situation, eliminate the bottleneck effect, improve system consistency, and ensure that the system has good charging and discharging efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating the steps of an energy storage output method with multiple subsystems according to an embodiment of the present invention;

[0014] Figure 2 This is a communication architecture diagram of an energy storage system with multiple subsystems according to an embodiment of the present invention;

[0015] Figure 3 This is a schematic diagram showing the connection between a subsystem and the power grid of an energy storage system with multiple subsystems, according to an embodiment of the present invention.

[0016] Label Explanation:

[0017] 1. Energy Management Unit; 2. Subsystem;

[0018] 11. Energy Management System; 21. Industrial Control Computer;

[0019] 21. Energy storage management unit; 22. Energy storage converter; 23. Battery cabinet. Detailed Implementation

[0020] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0021] Please refer to Figure 1 A method for energy storage output with multiple subsystems, comprising the following steps:

[0022] S1. Calculate the total energy storage output power that the energy storage system needs to provide to the load;

[0023] S2. Obtain the SOC ratio value of each subsystem in the energy storage system;

[0024] S3. Adjust the sub-output power of each subsystem according to the total energy storage output power and all the SOC ratio values.

[0025] As can be seen from the above description, the beneficial effects of the present invention are as follows: First, the total energy storage output power required by the energy storage system to be provided to the load is determined, and then the sub-output power of each subsystem is adjusted in combination with the SOC ratio value of each subsystem. Multiple subsystems can meet the capacity requirements of the load. By scheduling the energy of each subsystem, it is possible to effectively prevent a certain subsystem from operating at high power continuously, so that each subsystem can operate according to its own actual situation, eliminate the bottleneck effect, improve system consistency, and ensure that the system has good charging and discharging efficiency.

[0026] Further, step S1 specifically includes:

[0027] S10. Obtain the total power required by the load and the preset energy storage output ratio;

[0028] S11. The total power output of energy storage is obtained based on the total power required by the load and the preset energy storage output ratio.

[0029] As can be seen from the above description, by setting a preset energy storage output ratio value, the proportion of the total energy storage output power in the total power required by the load can be conveniently determined, which is flexible and easy to adjust.

[0030] Furthermore, step S1 also includes:

[0031] S12. Determine whether the total output power of the energy storage is greater than the remaining available capacity of the energy storage system. If yes, execute step S2; otherwise, obtain a new preset energy storage output ratio value and execute step S11.

[0032] As can be seen from the above description, when determining the total output power of energy storage, it is necessary to compare the remaining available capacity of the energy storage system to determine whether the energy storage system is capable of providing the total output power. If the energy storage system cannot provide the total output power, the preset energy storage output ratio value is obtained again, so as to make reasonable use of the energy storage system for energy supply and ensure the normal power supply on the load side.

[0033] Further, step S3 specifically includes:

[0034] Calculate the sub-output percentage of each subsystem based on the rated capacity of all the subsystems and the SOC ratio value;

[0035] The sub-output power of each subsystem is adjusted according to the total energy storage output power and the proportion of each sub-output.

[0036] As can be seen from the above description, setting the self-output ratio value determines the proportion of the subsystem's output capacity in the total output capacity of the energy storage system. In this way, the total energy storage output power is distributed to all subsystems according to the self-output ratio value, ensuring that the total output of all subsystems can meet the energy storage power ratio requirements, while avoiding the occurrence of a single subsystem continuously outputting high power, and effectively extending the battery life of the subsystem.

[0037] Furthermore, after step S3, the method further includes:

[0038] S4. If the sub-output power of the subsystem is greater than its rated power, then the sub-output power of the subsystem is reset to the rated power, and the portion of the original sub-output power exceeding the rated power is supplied by the power grid.

[0039] As can be seen from the above description, when the sub-output power of a certain subsystem is greater than its rated power, the power it needs to output is set to the rated power, and the grid supplements the remaining power, which effectively ensures that each subsystem can operate normally. The total energy storage output power of the energy storage system will not be affected because a single subsystem cannot provide the corresponding sub-output power, making the operation of the energy storage system more reasonable and efficient.

[0040] Further, step S3 specifically includes:

[0041] S31. Control the output of all subsystems according to the SOC ratio values ​​to make the current SOC ratio values ​​of all subsystems equal, and obtain the remaining total energy storage output power after deducting all the priority output power.

[0042] S32. Adjust the sub-output power of the subsystem according to the total output power of the remaining energy storage.

[0043] As can be seen from the above description, when configuring the sub-output power for each subsystem, controlling some subsystems to output power first based on the SOC ratio of the subsystems can effectively avoid the problem of SOC imbalance between subsystems in the energy storage system, improve system stability, and ensure efficient system operation.

[0044] Further, step S31 specifically includes:

[0045] S311. Determine from all the said subsystems a first target subsystem with the highest SOC ratio and a second target subsystem with the second highest SOC ratio;

[0046] S312. Obtain the priority output power of all first target subsystems based on the difference between the highest value and the second highest value and the rated capacity of the first target subsystem;

[0047] S313. Control all first target subsystems to output the priority output power until the current SOC ratio of the first target subsystem is equal to that of the second target subsystem, and deduct the priority output power from the total energy storage output power;

[0048] S314. Repeat steps S311 to S313 until the current SOC ratio values ​​of all subsystems are equal, and obtain the remaining total energy storage output power.

[0049] As can be seen from the above description, when adjusting the SOC proportional value, the subsystem outputs power sequentially from high to low, and the process is repeated multiple times. This method is logically sound and less prone to errors.

[0050] Furthermore, controlling all first target subsystems to output the priority output power specifically involves:

[0051] The sub-priority output power of each first target subsystem is obtained based on the proportion of the rated capacity of each first target subsystem to the total rated capacity of all first target subsystems and the priority output power.

[0052] Control the first target subsystem to output the corresponding sub-priority output power.

[0053] As can be seen from the above description, when controlling the output priority power of all first target subsystems, the priority output power is allocated according to the proportion of the rated capacity of each first target subsystem to the total rated capacity of all first target subsystems. That is, the rated capacity of each first target subsystem is different, and the amount of power it undertakes is also different. In other words, each subsystem adjusts its output power according to the target SOC, which not only meets the power demand of the load, but also avoids the problem of SOC imbalance caused by all the power being provided by one first target subsystem.

[0054] Please refer to Figure 2 and Figure 3 An energy storage system with multiple subsystems, including an energy management unit 1 and two or more subsystems 2;

[0055] The energy management unit 1 is communicatively connected to all the subsystems 2 and is used to execute the above-described energy storage output method with multiple subsystems.

[0056] As can be seen from the above description, the beneficial effects of the present invention are as follows: The energy storage system is divided into multiple independent subsystems, all controlled by an energy management unit. First, the total energy storage output power required by the energy storage system to supply the load is determined. Then, the sub-output power of each subsystem is adjusted based on its SOC ratio. Using multiple subsystems can meet the load's capacity requirements. Energy scheduling of each subsystem effectively prevents any single subsystem from operating at continuously high power, allowing each subsystem to operate according to its own actual situation, eliminating the bottleneck effect, improving system consistency, and ensuring good charging and discharging efficiency.

[0057] Furthermore, the subsystem 2 includes an energy storage management unit 21, an energy storage converter 22, and a battery cabinet 23;

[0058] The energy storage management unit is connected to the energy storage converter and the battery cabinet, respectively.

[0059] The energy management unit is communicatively connected to both the energy storage management unit and the energy storage converter.

[0060] As can be seen from the above description, each subsystem is equipped with an energy storage management unit and an energy storage converter, which can effectively prevent the failure of a single subsystem from affecting the normal operation of other subsystems, effectively improve the charging and discharging capacity of the energy storage system, and enhance system efficiency.

[0061] The energy storage output method and energy storage system with multiple subsystems of the present invention are applicable to scenarios of energy storage power supply. The following is a description through specific embodiments:

[0062] To better illustrate the content of this application, the parameter definitions appearing in the following embodiments are explained as follows:

[0063] Q: Preset energy storage output ratio;

[0064] B i : Rated capacity of the i-th battery subsystem;

[0065] B max : The rated capacity of the subsystem where the highest SOC value is located;

[0066] B 总 Remaining available capacity of energy storage systems

[0067] SOC i : The SOC ratio of the i-th subsystem;

[0068] SOC max : The SOC ratio of the first target subsystem;

[0069] SOC 次max: The SOC ratio of the second target subsystem;

[0070] K i : Represents the percentage of sub-outputs of the i-th subsystem;

[0071] P pcsi : Sub-output power of the i-th subsystem;

[0072] P pcsi额 : Rated power of the i-th subsystem PCS;

[0073] P 储能 Total power output of energy storage;

[0074] P 负载 Total power required by the load;

[0075] P 电网 : Output power on the grid side;

[0076] P pre Prioritize power output;

[0077] P′ prei : Sub-priority output power of the i-th first target subsystem;

[0078] P pre总 The sum of all prioritized output power;

[0079] P′ 储能 : Total output power of remaining energy storage.

[0080] Please refer to Figure 1 Embodiment 1 of the present invention is as follows:

[0081] A method for energy storage output with multiple subsystems, comprising the following steps:

[0082] S1. Calculate the total energy storage output power that the energy storage system needs to provide to the load;

[0083] In this embodiment, step S1 specifically includes:

[0084] S10. Obtain the total power required by the load and the preset energy storage output ratio;

[0085] S11. The total energy storage output power is obtained based on the total power required by the load and the preset energy storage output ratio. The relevant expression is as follows:

[0086] P 储能 =Q×P 负载 ;

[0087] P 负载 =P 电网 +P 储能 ;

[0088] P 电网 = (1-Q)×P 负载 ;

[0089] Where Q is 0, it means that all the power required by the load is output from the grid side, and Q is 1, it means that all the power required by the load is output from the energy storage system. In this embodiment, if Q is set to 0.5, the energy storage system will output half of the power required by the load, and the remaining half will be supplemented by the grid.

[0090] S12. Determine whether the total output power of the energy storage is greater than the remaining available capacity of the energy storage system. If yes, proceed to step S2; otherwise, obtain a new preset energy storage output ratio value and proceed to step S11.

[0091] In this embodiment, the total power required by the load is provided by the total output power of the energy storage system and the output power of the grid side. The total output power of the energy storage system is determined by setting a preset energy storage output ratio. When the total output power of the energy storage system is greater than the remaining available capacity of the energy storage system, it means that the current energy storage system is insufficient to provide the current total output power of the energy storage system. Therefore, the preset energy storage output ratio should be reduced to reduce the total output power of the energy storage system.

[0092] Specifically, if P 储能 >B 总 If the calculated output power required by the energy storage system exceeds the total available capacity of the energy storage system, and the energy storage system cannot meet the power demand of the load under this condition, then the EMS recalculates the Q value and adjusts the ratio of the energy storage system's output power to that of the grid. In this case, Q = B. 总 / P 负载 To ensure that the power supplied by the battery system does not exceed the limit, Q is rounded to one decimal place. If P 储能 ≤B 总 This means that the remaining power of the current energy storage system can meet the power demand of the load under this condition, and the system executes according to the strategy of the preset value Q.

[0093] S2. Obtain the SOC ratio of each subsystem in the energy storage system;

[0094] S3. Adjust the sub-output power of each subsystem according to the total energy storage output power and the ratio of all SOC values.

[0095] In this embodiment, step S3 specifically includes:

[0096] The sub-output percentage of each subsystem is calculated based on the rated capacity and SOC ratio of all subsystems, and the expression is as follows:

[0097]

[0098] The sub-output power of each subsystem is adjusted based on the total energy storage output power and the proportion of each sub-output, and the expression is as follows:

[0099] P pcsi =K i ×P 储能 .

[0100] S4. If the sub-output power of a subsystem is greater than the rated power of its own PCS, then the sub-output power of the subsystem is reset to the rated power, and the portion of the atomic output power exceeding the rated power is supplied by the power grid.

[0101] In this embodiment, when the total output power of the energy storage system is less than or equal to the remaining available capacity of the energy storage system, the ratio of the sum of the rated power of the PCS of each subsystem to the load power demand can be adjusted so that the subsystem outputs according to its own rated power. That is, when P 储能 ≤B 总 And P pcsi >P pcsi额 At that time, P pcsi =P pcsi额 , I = ∑P pcsi额 / P 负载 Where I represents the ratio of the sum of the rated power of the PCS of each subsystem to the power demand of the load.

[0102] Embodiment 2 of the present invention is as follows:

[0103] An energy storage output method with multiple subsystems, based on the above embodiment one, in order to adjust the SOC of each subsystem to the same level, the specific implementation process of step S3 is replaced as follows:

[0104] S31. Control the output power of all subsystems according to the SOC ratio values ​​so that the current SOC ratio values ​​of all subsystems are equal, and obtain the total energy storage output power after deducting all priority output power.

[0105] In this embodiment, step S31 specifically includes:

[0106] S311. Determine the first target subsystem with the highest SOC ratio and the second target subsystem with the second highest SOC ratio from all subsystems;

[0107] S312. Obtain the priority output power of all first target subsystems based on the difference between the highest and second highest values ​​and the rated capacity of the first target subsystem;

[0108] In this embodiment, all subsystems are arranged from highest to lowest SOC value. For example, subsystem a has the highest SOC, subsystem b has the second highest SOC, and subsystem c has the third highest SOC. a>SOC b >SOC c ...select the first target subsystem and the second target subsystem that meet the above conditions; if there is only one first target subsystem, the expression for the priority output power is:

[0109] P pre =P pcsa =(SOC) max -SOC 次max )×B max ;

[0110] Among them, B max This refers to the rated capacity of the first target subsystem in the subsystem.

[0111] If the first target subsystem contains two or more subsystems, the expression for the priority output power is:

[0112] P pre =(SOC) max -SOC 次max )×∑B max ;

[0113] Where, ∑B max This refers to the total fixed capacity of all first-target subsystems in the subsystem;

[0114] S313. Control all first target subsystems to output priority output power until the current SOC ratio of the first target subsystem is equal to that of the second target subsystem, and deduct the priority output power from the total energy storage output power.

[0115] In this embodiment, controlling the output power of all first target subsystems to prioritize output power specifically involves:

[0116] The sub-priority output power of each first target subsystem is obtained by taking the rated capacity of each first target subsystem as a percentage of the total rated capacity of all first target subsystems and the priority output power. The expression for this is:

[0117] P' prei = (B i / ∑B max )×P pre ;

[0118] Among them, B i This represents the rated capacity of the i-th first target subsystem in the subsystem.

[0119] Control the output power of the first target subsystem to correspond to the sub-priority output power.

[0120] S314. Repeat steps S311 to S313 until the current SOC ratio of all subsystems is equal, and obtain the remaining total energy storage output power.

[0121] In this embodiment, after repeatedly determining the first target subsystem and allowing it to output its priority power, the State of Charge (SOC) of each subsystem is at the same level. The total energy storage output power is obtained by subtracting all the generated priority output power, and the final expression is:

[0122] P′ 储能 =P 储能 -P pre总 ;

[0123] S32. Adjust the sub-output power of the subsystem according to the total output power of the remaining energy storage, and the expression is:

[0124]

[0125] Please refer to Figure 2 and Figure 3 Embodiment 3 of the present invention is as follows:

[0126] An energy storage system with multiple subsystems, such as Figure 2 As shown, it includes an energy management unit and two or more subsystems;

[0127] The energy management unit is communicatively connected to all subsystems and is used to execute an energy storage output method with multiple subsystems according to Embodiment 1 or 2.

[0128] In this embodiment, as Figure 3 As shown, by adding a sampling point at the main incoming line of the microgrid system, the voltage and current values ​​currently input to the microgrid system from the grid side can be collected. The collected voltage and current values ​​are then uploaded to the energy management unit through the acquisition device. The energy management unit can calculate the total power input to the microgrid system from the grid side in real time, which is the power currently required by the load.

[0129] In this embodiment, as Figure 2As shown, the subsystem includes an energy storage management unit, an energy storage converter, and a battery cabinet. The energy storage management unit is connected to both the energy storage converter and the battery cabinet. The energy management unit is communicatively connected to both the energy storage management unit and the energy storage converter. The number of battery cabinets in each subsystem can vary, meaning the rated capacity of each subsystem can differ. Each subsystem is connected to one energy storage converter and is configured with one energy storage management unit. Each subsystem can be considered an independent energy storage unit. The energy storage management unit is responsible for collecting and transmitting data, managing and monitoring the battery clusters, and each energy storage management unit communicates with the energy management unit, allowing control and management of each subsystem through the energy management unit. The energy management unit integrates the functions of an industrial control computer 12, communication equipment, control modules, and an energy management system 11 (EMS), enabling monitoring and management of each subsystem. The energy management unit can monitor various system data in real time, monitor the current system status, detect alarms, and perform energy dispatching functions.

[0130] In summary, this invention provides an energy storage output method and system with multiple subsystems. First, the total energy storage output power required by the energy storage system to supply the load is determined. Then, the sub-output power of each subsystem is adjusted by combining the SOC ratio of each subsystem. Using multiple subsystems can meet the capacity requirements of the load. By scheduling the energy of each subsystem, it is possible to effectively prevent a certain subsystem from operating at high power continuously, so that each subsystem can operate according to its own actual situation, eliminating the bottleneck effect, improving system consistency, and ensuring that the system has good charging and discharging efficiency.

[0131] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for energy storage output with multiple subsystems, characterized in that, Including the following steps: S1. Calculate the total energy storage output power that the energy storage system needs to provide to the load; S2. Obtain the SOC ratio value of each subsystem in the energy storage system; S3. Adjust the sub-output power of each subsystem according to the total energy storage output power and all the SOC ratio values; Step S3 specifically involves: S31. Control the output of all subsystems according to the SOC ratio values ​​to make the current SOC ratio values ​​of all subsystems equal, and obtain the remaining total energy storage output power after deducting all the priority output power. S32. Adjust the sub-output power of the subsystem according to the remaining total energy storage output power, the expression of which is: ; in, B is the sub-output power of the i-th subsystem; i Let be the rated capacity of the i-th battery subsystem; Output total power for the remaining energy storage; Step S31 specifically involves: S311. Determine from all the said subsystems a first target subsystem with the highest SOC ratio and a second target subsystem with the second highest SOC ratio; S312. Obtain the priority output power of all first target subsystems based on the difference between the highest value and the second highest value and the rated capacity of the first target subsystem; S313. Control all first target subsystems to output the priority output power until the current SOC ratio of the first target subsystem is equal to that of the second target subsystem, and deduct the priority output power from the total energy storage output power; S314. Repeat steps S311 to S313 until the current SOC ratio values ​​of all subsystems are equal, and obtain the remaining total energy storage output power.

2. The energy storage output method with multiple subsystems according to claim 1, characterized in that, Step S1 specifically involves: S10. Obtain the total power required by the load and the preset energy storage output ratio; S11. The total power output of energy storage is obtained based on the total power required by the load and the preset energy storage output ratio.

3. The energy storage output method with multiple subsystems according to claim 2, characterized in that, Step S1 further includes: S12. Determine whether the total output power of the energy storage is greater than the remaining available capacity of the energy storage system. If yes, execute step S2; otherwise, obtain a new preset energy storage output ratio value and execute step S11.

4. The energy storage output method with multiple subsystems according to claim 1, characterized in that, Step S3 specifically involves: Calculate the sub-output percentage of each subsystem based on the rated capacity of all the subsystems and the SOC ratio value; The sub-output power of each subsystem is adjusted according to the total energy storage output power and the proportion of each sub-output.

5. The energy storage output method with multiple subsystems according to claim 1, characterized in that, The step S3 is followed by: S4. If the sub-output power of the subsystem is greater than the rated power of its own PCS, then the sub-output power of the subsystem is reset to the rated power, and the portion of the original sub-output power exceeding the rated power is supplied by the power grid.

6. The energy storage output method with multiple subsystems according to claim 1, characterized in that, The specific steps of controlling all first target subsystems to output the priority output power are as follows: The sub-priority output power of each first target subsystem is obtained based on the proportion of the rated capacity of each first target subsystem to the total rated capacity of all first target subsystems and the priority output power. Control the first target subsystem to output the corresponding sub-priority output power.

7. An energy storage system with multiple subsystems, characterized in that, Includes an energy management unit and two or more subsystems; The energy management unit is communicatively connected to all the subsystems and is used to execute the energy storage output method with multiple subsystems as described in any one of claims 1 to 6.

8. An energy storage system with multiple subsystems according to claim 7, characterized in that, The subsystem includes an energy storage management unit, an energy storage converter, and a battery cabinet; The energy storage management unit is connected to the energy storage converter and the battery cabinet, respectively. The energy management unit is communicatively connected to both the energy storage management unit and the energy storage converter.

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