Power control correction method and system for an energy storage system

Abstract

The application belongs to the field of power control correction, and particularly relates to a power control correction method and system for an energy storage system. A set load tracking algorithm is used to correct a planned power value at a current time in a planned curve, and power distribution is performed on energy storage charging and discharging equipment according to the corrected planned value. The algorithm includes: when planning discharging, taking a smaller value between a load power determined by a superimposed power corresponding to a total power of grid discharging power and energy storage discharging power at the current time and a planned power; obtaining a corrected planned power value according to a larger value between the smaller value and a set lower limit value of the load power; when planning charging, taking a smaller value between a positive value of a maximum power demand in the month and a positive value of an upper limit of transformer load, and taking a larger value between a difference between the smaller value and the superimposed power value and the planned power value; and obtaining the corrected planned power value according to a smaller value between the larger value and a set upper limit value of the discharging power.

Description

Technical Field

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

[0002] like Figure 1 As shown, the industrial and commercial energy storage system is connected to the low-voltage bus of the power grid (which, along with the energy storage system, supplies power to the load or charges the energy storage system). Based on the load's electricity demand at different times, the output power of the energy storage system is dynamically adjusted, thereby regulating the transformer demand, peak shaving and valley filling, and peak-valley arbitrage. Simultaneously, the energy storage system can also be used as a backup power source. The entire energy storage system must have protection functions such as preventing overcharging and over-discharging, preventing transformer power reverse current, energy storage battery protection, and system fault protection. Currently, most industrial and commercial integrated energy storage unit paralleling solutions use a method where all data from the integrated energy storage units is collected and aggregated by the internal Energy Management Unit (EMU) and then uploaded separately to the cloud.

[0003] The EMU software architecture and module design can be based on the "Development Specification for Micro-applications of Intelligent Converged Terminals in Distribution Areas" issued by the China Electric Power Research Institute. According to the different functions of the modules, they can be classified into four categories: access modules, data center modules, edge computing modules, and communication modules. The MQTT message bus mechanism is used to realize communication between the modules.

[0004] The energy storage system distributes planned power curves through an edge computing module. A planned power curve is a pre-defined charging and discharging schedule based on peak, off-peak, and valley electricity consumption periods. It incorporates peak-shaving and valley-filling strategies (e.g., during valley periods when electricity costs are low, the energy storage system is used for charging; during peak periods when electricity costs are high, the energy storage system is used for discharging to reduce high electricity prices). Different charging and discharging powers can be executed based on varying electricity demand during different time periods. For example, if the demand is 300kW from 10:00 AM to 12:00 PM and 100kW from 12:00 PM to 1:00 PM, and the system's maximum power is 200kW, then a full-power discharge of 200kW can be executed from 10:00 AM to 12:00 PM, while from 12:00 PM to 1:00 PM, the energy storage system only needs to provide less than or equal to 100kW of power). Generally, one planned power curve contains the charging and discharging plan for the entire day. Users can implement different control frequencies based on the control frequency (the default planned power distribution frequency is generally 15 minutes per cycle).

[0005] However, during actual operation, there is a certain degree of deviation or discrepancy between the planned power curve issued by the edge computing module and the actual operating conditions of the energy storage system. This deviation may stem from various factors, including but not limited to errors in load forecasting, fluctuations in renewable energy generation, temporary changes in equipment status, or adjustments to system control strategies. If power control is blindly implemented according to the issued planned power curve (which may be poorly configured) without considering actual operating conditions, problems such as reverse current in the energy storage system, increased maximum power demand, and grid transformer overload may occur due to the flawed planned power curve. Summary of the Invention

[0006] The purpose of this invention is to provide a power control correction method and system for energy storage systems, which solves the problems of reverse power flow, increased maximum power demand, and transformer overload in the energy storage system caused by blindly following the issued planned curves for power control without considering the actual operating conditions of the energy storage system.

[0007] To achieve the above objectives, the present invention provides a power control correction method for an energy storage system. The method corrects the planned power value corresponding to the current time in the obtained planning curve according to a set load tracking algorithm, and allocates power to the energy storage charging and discharging devices in the energy storage system according to the corrected planned power value.

[0008] The specified load tracking algorithm includes:

[0009] When the energy storage system plans to discharge, the smaller value between the load power consumption and the planned power, which are determined by the superimposed power corresponding to the grid discharge power and the total power of the energy storage discharge at the current moment, is taken in the direction of discharge to the load. The corrected planned power value is obtained by taking the larger value between the smaller value and the value of the set lower limit of power consumption in the direction of discharge to the load.

[0010] When the energy storage system is scheduled to charge, the smaller of the positive value of the current corresponding monthly maximum power demand and the positive value of the transformer load limit corresponding to the power grid is taken. The larger of the difference between the smaller value and the value of the superimposed power in the direction of discharge to the load is compared with the value of the planned power in the direction of discharge to the load. Then, the corrected planned power value is obtained based on the smaller of the larger value and the value of the set discharge power limit in the direction of discharge to the load.

[0011] Beneficial Effects: This invention provides a novel power control correction method for energy storage systems. This method corrects the planned power value represented by the planning curve according to a set load tracking algorithm, thereby allocating more reasonable planned power values ​​to the energy storage charging and discharging devices in the energy storage system. This set load tracking algorithm employs different calculation methods for planned charging and planned discharging scenarios during power correction.

[0012] When the energy storage system plans to discharge, it compares the vector value of the load's power consumption in the direction of discharge to the load (this value is determined by the superposition of the current grid discharge power and the total energy storage discharge power; it is usually positive when the direction of discharge to the load is considered positive; when the grid power is too high, excessive energy will be generated, and the load cannot consume the energy normally, so the value will become negative, indicating that the energy storage needs to be charged, and the energy storage will share the burden) with the current planned power value, and takes the smaller value. Since the energy storage system is planned to discharge, this smaller value is usually positive. When the smaller value is negative, it indicates that energy storage needs to be charged. In this case, for the energy storage system, if the smaller value is negative and the absolute value is small, energy storage can be charged according to the smaller value. However, if the smaller value is negative and the absolute value is large, in order to limit the power consumption for charging energy storage, charging energy storage can be carried out according to the set lower limit of load power consumption. The set lower limit of load power consumption is less than or equal to 0, which is opposite to the direction of discharging to the load. Therefore, the larger value (i.e., the smaller absolute value) between the smaller value and the set lower limit of load power consumption is taken as the corrected planned power value to participate in power allocation. When the energy storage system is scheduled to charge, the maximum margin value available for energy storage is obtained by subtracting the vector value of the load demand power in the direction of discharge to the load (this value is the smaller of the positive value of the maximum monthly power demand and the positive value of the grid transformer load limit in the direction of discharge to the load, i.e., the load demand power cannot exceed the maximum monthly power demand or the grid transformer load limit) from the vector value of the superimposed power of the energy storage system and the grid in the direction of discharge to the load. (Since the load has a power demand, and the superimposed power of the energy storage system and the grid needs to meet the load demand power; therefore, the difference between the superimposed power of the energy storage system and the grid and the load demand power is the maximum margin value available for energy storage after meeting the load's charging demand.)Take the larger of the margin value and the current planned power value in the direction of load discharge (since the planned charging direction of the energy storage system is opposite to the direction of load discharge, the planned power vector value when the energy storage system is planned to charge is negative, and the margin value is also in the direction of load discharge, usually taking a negative value. The larger of the two negative values ​​is the smaller absolute value. That is, if the maximum margin is more than the planned power, the energy storage system is still charged according to the planned power; if the maximum margin is insufficient compared to the planned power, the energy storage system is charged or discharged according to the maximum margin. The energy storage system is charged when the maximum margin is negative and discharged when the maximum margin is positive). Then take the larger value. The smaller of the value and the set upper limit of discharge power in the direction of discharge to the load (since the larger value is usually negative in the direction of discharge to the load, when the larger value is positive, it indicates that energy storage is needed to discharge to the load. If the larger value is less than the set upper limit of discharge power, the energy storage can still be controlled to discharge at a power lower than the set upper limit of discharge power. If the larger value is greater than the set upper limit of discharge power, in order to limit the power of energy storage discharge, the discharge is selected according to the set upper limit of discharge power; the set upper limit of discharge power is in the same direction as the discharge to the load, so the value is greater than or equal to 0) is used as the corrected planned power value to participate in power allocation.

[0013] In summary, this method can track load power in real time and generate accurate and reasonable correction values, which are then distributed to each energy storage unit to ensure accurate and reasonable power consumption. This avoids problems such as power backflow, increased maximum power demand, and transformer overload caused by unreasonable planning curves in the energy storage system.

[0014] Furthermore, the method of determining the load power consumption based on the superimposed power corresponding to the grid discharge power and the total energy storage discharge power obtained at the current moment includes: taking the power after adjustment by the coefficient corresponding to the superimposed power as the load power consumption.

[0015] If the direction of the superimposed power corresponding to the current grid discharge power and the total energy storage discharge power is towards the load discharge direction, then the coefficient corresponding to the superimposed power is determined to be a set discharge coefficient that is not less than 0 and less than 1; otherwise, the coefficient corresponding to the superimposed power is determined to be a set charging coefficient that is greater than or equal to 1.

[0016] Furthermore, the method of determining the load power consumption based on the superimposed power corresponding to the grid discharge power and the total energy storage discharge power obtained at the current moment includes: taking the power after adjustment by the coefficient corresponding to the superimposed power as the load power consumption.

[0017] If the direction of the superimposed power corresponding to the grid discharge power and the total energy storage discharge power obtained at the current moment is towards the load discharge direction, then the coefficient corresponding to the superimposed power is determined to be the sum of the set discharge coefficient which is not less than 0 and less than 1 and the discharge power offset which is less than or equal to 0; otherwise, the coefficient corresponding to the superimposed power is determined to be the sum of the set charging coefficient which is greater than or equal to 1 and the charging power offset which is less than or equal to 0.

[0018] Furthermore, the method of allocating power to the energy storage charging and discharging devices in the energy storage system according to the revised planned power value includes average allocation; the average allocation is to obtain the power value allocated to each energy storage charging and discharging device by multiplying the ratio of the maximum available power value of each energy storage charging and discharging device to the maximum available total power value of the energy storage system with the revised planned power value; the maximum available power value of each energy storage charging and discharging device is less than or equal to the maximum available total power value of the entire station.

[0019] Furthermore, the method of allocating power to the energy storage charging and discharging devices in the energy storage system according to the revised planned power value includes equalization allocation; the equalization allocation includes:

[0020] The charging set power value allocated to each energy storage charging and discharging device is obtained by multiplying the ratio of the remaining power value corresponding to the real-time SOC of each energy storage charging and discharging device to the remaining power value corresponding to the average SOC of all energy storage charging and discharging devices, and the product of the difference between the corrected planned power value and the sum of the available maximum power of all energy storage charging and discharging devices operating at full power and the ratio of the number of energy storage charging and discharging devices operating at non-full power.

[0021] The discharge set power value allocated to each energy storage charging and discharging device is obtained by multiplying the ratio of the real-time SOC of each energy storage charging and discharging device to the average SOC of all energy storage charging and discharging devices, the difference between the corrected planned power value and the sum of the available maximum power of all energy storage charging and discharging devices operating at full power, and the ratio of the number of energy storage charging and discharging devices operating at non-full power.

[0022] If the charging power setting value allocated to each energy storage charging and discharging device satisfies the condition that it is less than or equal to the maximum available power value of the corresponding energy storage charging and discharging device, then each energy storage charging and discharging device is charged according to the allocated charging power setting.

[0023] If the discharge setting power value allocated to each energy storage charging and discharging device satisfies the condition that it is less than or equal to the maximum available power value of the corresponding energy storage charging and discharging device, then each energy storage charging and discharging device discharges according to the allocated discharge setting power.

[0024] If there is a situation where the set charging power value or the set discharging power value allocated to a certain energy storage charging and discharging device does not meet the corresponding conditions, then the energy storage charging and discharging device will operate at full power. At the same time, the number of energy storage charging and discharging devices operating at full power will be updated. Then, the calculation will be repeated according to the balanced allocation method until the situation where the set charging power value or the set discharging power value does not meet the corresponding conditions no longer occurs in a certain calculation, or until all energy storage charging and discharging devices operate at full power.

[0025] Furthermore, the method for determining the maximum power demand for the current month includes: if the maximum power demand for the current month is obtained, then the obtained maximum power demand for the current month is directly determined as the current maximum power demand for the current month; if the maximum power demand for the current month cannot be obtained, then the preset minimum monthly demand is determined as the current maximum power demand for the current month.

[0026] Furthermore, the step of correcting the planned power value corresponding to the current time in the obtained planned curve according to the set load tracking algorithm, and allocating power to the energy storage charging and discharging devices in the energy storage system according to the corrected planned power value is realized by the host in the energy storage system; the energy storage charging and discharging devices in the energy storage system include a set Internet of Things energy management unit.

[0027] The host is a single energy storage charging and discharging device arbitrarily selected from all energy storage charging and discharging devices. The IoT-based energy management unit in the host is used to collect data from the host; it is also used to communicate with the IoT-based energy management units of each slave device to collect data from each slave device and send the power allocation results of each slave device obtained by power allocation.

[0028] Furthermore, the IoT-enabled EMU device in the host is also used to communicate with the cloud to upload the collected data to the cloud or receive information sent down from the cloud.

[0029] Furthermore, after the host is selected, automatic network configuration is performed on the host and each slave device to establish communication between the host and each slave device;

[0030] The automatic networking setup includes: each slave device automatically connects to the host according to the default IP address of the maintenance network port configured by the host; the host searches for slave devices through timed broadcasts, the slave devices respond to the host with their identity attributes according to the timed broadcast messages, the host verifies the legitimacy of each slave device according to its corresponding identity attributes, and establishes a communication connection between the host and the verified slave devices.

[0031] The present invention also provides a power control correction system for an energy storage system, including a processor for executing a computer program to implement the steps of the power control correction method for the energy storage system described above.

[0032] The power control correction system of this energy storage system can achieve the same beneficial effects as the power control correction method of the energy storage system described above. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the energy storage system in the background art of this invention;

[0034] Figure 2 This is a flowchart illustrating the power control correction method for an energy storage system in an embodiment of the present invention.

[0035] Figure 3 This is a module interaction example diagram of the internal modules of the EMU device in an embodiment of the power control correction method for the energy storage system of the present invention;

[0036] Figure 4 This is an example diagram of the master-slave architecture of the EMU device in an embodiment of the power control correction method for the energy storage system of the present invention;

[0037] Figure 5 This is an example diagram illustrating the application of the power control correction method for the energy storage system of the present invention, which manages the slave EMU device through the EMU device in the host. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0039] Example of a power control correction method for energy storage systems

[0040] This embodiment presents a technical solution for a power control correction method for an energy storage system. This method corrects the planned power value reflected in the received planning curve in real time according to a set load tracking algorithm, making the planned power value more accurate and consistent with the actual situation. Then, power is allocated to the integrated energy storage unit according to the corrected planned power value. The load tracking algorithm essentially divides the planned discharge and planned charging of the energy storage system into two cases, filtering the superimposed power corresponding to the current grid discharge power and the total energy storage discharge power under different conditions. This conditional filtering is used as a correction method, ultimately yielding a corrected planned power value that is more accurate and closer to the actual situation than the unfiltered planned power value. If power allocation is performed based on the corrected planned power value, the planned power value in the planning curve can be corrected in a timely manner, avoiding problems such as power backflow caused by unreasonable power allocation that could endanger the safety of the entire energy storage system.

[0041] In this embodiment, according to Figure 2The load tracking algorithm shown corrects the planned power value corresponding to the current time in the obtained planned curve, and allocates power to the energy storage charging and discharging devices in the energy storage system according to the corrected planned power value (in this embodiment, the energy storage charging and discharging device can be an integrated energy storage unit, that is, a device that integrates energy storage charging, energy storage discharging and corresponding control functions; in other embodiments, other energy storage charging and discharging devices can also be used).

[0042] like Figure 2 As shown, the load tracking algorithm in this embodiment specifically includes:

[0043] When the energy storage system plans to discharge, the grid discharge power P obtained at the current time is taken. t The total power P of energy storage and discharge e The smaller of the load power consumption and the planned power in the direction of load discharge, determined by the corresponding superimposed power, is used to obtain the corrected planned power value.

[0044] When the energy storage system is scheduled to charge, the smaller of the current positive value of the maximum monthly power demand and the positive value of the transformer load limit of the grid is taken. The larger of the difference between this smaller value and the value of the superimposed power in the direction of discharge to the load is compared with the value of the planned power in the direction of discharge to the load. Then, the corrected planned power value is obtained based on the smaller of this larger value and the value of the set discharge power limit in the direction of discharge to the load.

[0045] Specifically, the method of determining the load power consumption based on the superimposed power corresponding to the grid discharge power and the total energy storage discharge power obtained at the current moment includes: taking the power after adjustment by the coefficient corresponding to the superimposed power as the load power consumption.

[0046] If the grid discharge power P obtained at the current moment t (This refers to the real-time power at the transformer's output terminal, which is typically read from the transformer's gate meter; normally it is negative, but may be positive in abnormal situations such as reverse current.) and the total power P of energy storage and discharge. e (This value is generally read from the energy storage grid connection table of the PCS; it is negative when the energy storage system is charging and positive when discharging.) If the direction of the superimposed power is towards the load discharge direction, then the coefficient corresponding to this superimposed power is determined to be a set discharge coefficient K that is not less than 0 and less than 1. d (i.e., 0≤K) d <1) Discharge power offset B less than or equal to 0 d (i.e. B) d The sum of (≤0); otherwise, the coefficient corresponding to the superimposed power is determined to be a set charging coefficient K greater than or equal to 1. c(i.e. K) c ≥1) and charging power offset B less than or equal to 0 c (i.e. B) c ≤0).

[0047] The above-mentioned charging coefficient K is set c With charging power offset B c The sum and the set discharge coefficient K d With discharge power offset B d The sum is actually used to adjust the energy storage output ratio, minimizing the power output of the transformer while ensuring it still has a certain output power (to avoid power fluctuations around zero). However, since the load power varies, K is set... d This is also to ensure that the output power of the energy storage is less than the load power when discharging; that is, to ensure that there is a margin when supplying power to the load, preventing the load power from suddenly changing to a very small value during load tracking gaps (these gaps last on the order of seconds, for example, adjusting once every 2 seconds), which could cause electrical energy to flow back to the grid through the transformer, thus affecting grid quality or damaging electrical equipment. When the transformer output power is particularly low, the energy storage system is not needed to supply power, and even a slight change in power can cause backflow. Relying solely on K... d Precise control of power changes may no longer be possible. (Set B) d This is to ensure that the energy storage system can discharge power only when the transformer reaches a certain output power.

[0048] And setting K c Then if -(P t -P e If the value is less than 0, it indicates that excessive power output has exceeded the load demand. In this case, more energy should be charged to the energy storage system so that as much of the power supplied by the grid as possible is consumed by the energy storage system, thus reducing the burden on the load. (Set B) c This is to ensure that the energy storage system absorbs more electrical energy, thereby ensuring that the transformer always has a certain output power and avoiding the phenomenon of the transformer power fluctuating up and down at zero point.

[0049] Therefore, in other embodiments, the discharge power offset B may not be set. d and charging power offset B c That is, if the direction of the superimposed power corresponding to the current grid discharge power and the total energy storage discharge power is towards the load discharge direction, then the coefficient corresponding to this superimposed power is determined to be a set discharge coefficient K that is not less than 0 and less than 1. d (i.e., 0≤K) d <1); otherwise, the coefficient corresponding to the superimposed power is determined to be a set charging coefficient K greater than or equal to 1. c (i.e. K) c ≥1).

[0050] In other embodiments, if there is photovoltaic power generation in the factory area, it indicates that the photovoltaic power generation has met the load requirements. At this time, the energy storage system does not need to exert any more power or switch to charging mode to help consume excess electrical energy, but this contradicts the discharge command issued by the cloud platform.

[0051] Taking the direction of discharge to the load as positive as an example: If the direction of discharge to the load is taken as positive, the vector expression for the superimposed power can be expressed as: -(P t -P e That is, the inherent meaning of the value of this superimposed power is: the grid discharge power P t The total power P of energy storage and discharge e The sum of the power applied to the load. Since the grid discharge power and the load discharge power are in the same direction, therefore P t This direction is represented as a positive value; since the total power of the energy storage discharge is opposite to the direction of the load discharge, P e This direction is represented as a negative value. From the inherent meaning of this superimposed power, we know that its direction is also the same as the load discharge direction; therefore, (P) t -P e In this direction, it is represented as a negative value, that is, -(P) t -P e ).

[0052] When the energy storage system plans to discharge (i.e., when the master station plans to issue the power value P) p When the power value is greater than 0, the formula for correcting the planned power value according to the algorithm (when the coefficient is not superimposed with the offset) is as follows:

[0053] P s =MAX(MIN(-(P) t -P e )*(-(P t -P e )>0? K d :K c ),P p ),P min_chg )

[0054] After superimposing the charging power offset and the discharging power offset, the formula for correcting the planned power value according to this algorithm is as follows:

[0055] P s =MAX(MIN(-(P) t -P e )*(-(P t -P e )>0? K d :K c )+(-(P t -P e)

[0056] >0? B d :B c ),P p ),P min_chg )

[0057] Among them, P s The revised planned power value; P t P is the power discharged to the power grid. e K represents the total power of energy storage and discharge. d To set the discharge coefficient, B d For discharge power offset, paired with K d Use; K c To set the charging coefficient, B c For charging power offset, paired with K c Use; P p Planned power value issued by the main station; P min_chg This is the set lower limit value for the load power consumption.

[0058] This embodiment addresses the planned power P. p Specific methods for power correction include:

[0059] When the energy storage system plans to discharge, the superimposed power is screened according to corresponding conditions; this screening first considers the load power (in this embodiment, the load power is the superimposed power - (P)). t -P e The power after adjusting the corresponding coefficient can be expressed as the power obtained by setting the discharge coefficient K. d and discharge power offset B d Or set the charging coefficient K c and charging power offset B c The adjusted superimposed power (the specific coefficient and power offset used for adjustment depends on the sign of the vector value of the superimposed power in the direction of discharge to the load) is compared with the planned power P. p The values ​​are compared to each other, and the smaller value is selected. After selecting the smaller value, it is compared with the set lower limit of the load power consumption, and the larger value is selected. After completing all the screening, the power correction can reasonably meet the following conditions:

[0060] When P t Under normal conditions (i.e., normal grid discharge without excessive discharge power), the load power consumption is determined by setting the discharge coefficient K. d and discharge power offset B d Or set the charging coefficient K c and charging power offset B c Adjusted superposition power - (P t-P e The value in the direction of discharge to the load is usually a positive value (i.e., greater than 0); at this time, the load power consumption and P are selected. p The smaller value among the two ensures that: if the load power consumption is greater than or equal to the planned power allocation, the load power consumption can fully meet the plan, and power can be allocated according to the plan; after adjustment, the power allocated to the energy storage unit can both meet the plan and avoid waste. If the load power consumption is less than the planned power allocation, the load power consumption is insufficient to provide the planned power, and the smaller value among the two is also selected; since only the load power can be provided at most in this case, the selected load power is sufficient.

[0061] After filtering out the smaller values, compare this smaller value with the set lower limit value P for load power consumption. min_chg (This value is usually set to 0 or slightly less than 0) Compare the calculated load power with the planned power, and select the larger value; when the calculated load power is in the same direction as the planned power, for example, if the original plan was to discharge, the actual calculated load power also indicates the actual power required to discharge; and because P min_chg The default value is usually 0 or slightly less than 0. Generally, this value will be less than the positive value of the actual calculated load power consumption. Therefore, this filter will select the larger value mentioned above, rather than P. min_chg The larger value is used as the revised planned power.

[0062] When P t In cases of excessive power generation (i.e., excessive electrical energy production), the load power consumption is determined by setting the discharge coefficient K. d With discharge power offset B d Or set the charging coefficient K c With charging power offset B c Adjusted superposition power - (P t -P e The value is less than 0 (meaning the load cannot consume all the electrical energy and energy storage is needed to share the power consumption); in this case, the actual power is allowed to be opposite to the planned power. That is, the original plan was to discharge, but after calculation, it was found that the superimposed power was negative, indicating that charging was actually needed. In this case, the P value can be preset. min_chg Charging is performed at the maximum power consumption. Therefore, P will be selected. min_chg (i.e., the set lower limit of load power consumption), with this P min_chg The revised planned power is equivalent to using the set lower limit of load power consumption as the revised planned power value to prevent reverse flow.

[0063] When the energy storage system plans to charge, it takes the smaller of the current corresponding monthly maximum power demand (the method for determining the monthly maximum power demand includes: if the monthly maximum power demand is obtained, then the obtained monthly maximum power demand is directly determined as the current corresponding monthly maximum power demand; if the monthly maximum power demand cannot be obtained, then the preset monthly minimum demand is determined as the current corresponding monthly maximum power demand) and the positive value of the grid transformer load limit corresponding to the grid. It then takes the larger of the difference between this smaller value and the value of the superimposed power in the direction of discharge to the load, and the value of the planned power in the direction of discharge to the load. Finally, it takes the smaller of this larger value and the value of the set discharge power limit in the direction of discharge to the load to obtain the corrected planned power value.

[0064] When the energy storage system is scheduled to charge (i.e., when the master station plans to issue the power value P) p When the power value is less than 0, the formula for correcting the planned power value according to this algorithm is as follows:

[0065] P s =MIN(MAX((-MIN(P) max_t ,MAX(P max_de ,P mix_de ))-(P t -P e )),P p ),P max_dischg )

[0066] Among them, P max_t P is a positive value representing the upper limit of the power grid transformer load; max_de This represents the maximum power demand for the current month; P mix_de Minimum monthly requirement; P max_dischg This is the set upper limit of discharge power in the direction of discharge to the load; the meanings of other parameters are the same as those of the parameters for planned charging of the energy storage system, and will not be repeated here.

[0067] Additionally, when the main station plans to issue the power value P p When the power is 0, no further correction is needed; simply execute the operation as if the power is 0.

[0068] This embodiment involves conditionally filtering the superimposed power during planned charging of the energy storage system. This filtering first compares the smaller of the positive value of the maximum monthly power demand and the positive value of the grid transformer load limit in the direction of load discharge, selecting the smaller value. In other words, the load demand power must not exceed either the maximum monthly power demand or the grid transformer load limit. Then, the difference between this smaller value and the superimposed power values ​​in the direction of load discharge (this difference implies the grid's capacity to charge the energy storage beyond the load demand; this difference may be positive, indicating excessive load demand requiring energy storage output to alleviate grid pressure, otherwise potentially increasing transformer demand or exceeding the transformer load limit) and the planned power value P issued by the master station are compared. p The values ​​are compared, and the smaller absolute value is selected (since both are usually negative, selecting the larger of the two actual values ​​is equivalent to selecting the smaller absolute value). In other words, if the power grid has a margin greater than or equal to the planned power value P for charging energy storage while meeting load demand, then... p This indicates that there is sufficient margin, and at this point, it is only necessary to proceed according to the planned power value P. p Power can be allocated; if this margin is insufficient to meet the planned power value P p If the margin is insufficient, it indicates that the load demand must be met first. As for the power used to charge the energy storage, only the calculated difference is used as the corrected power value for power allocation.

[0069] Finally, the smaller value selected is compared with the set upper limit of discharge power P. max_dischg (The setting principle of this value is the same as the set lower limit value P of the load power consumption) min_chg Similarly, the smaller value is selected through comparison and then chosen as the corrected planned power value. This selection ensures that when the remaining capacity to charge the energy storage is greater than or equal to the planned power value issued by the main station, the planned power value is selected to meet the planned charging requirements without wasting energy. Furthermore, when the remaining capacity to charge the energy storage is less than the planned power value issued by the main station, the remaining capacity is selected to prevent the maximum power demand from increasing and the transformer from overloading.

[0070] The principle behind selecting operations with smaller absolute values ​​is that a smaller absolute value indicates a smaller transformer output. The reasons for this smaller transformer output can be discussed in two scenarios: one is that the load power is indeed relatively small, and in this case, if the energy storage is discharging, it will be based on K... d and B d Reduce the discharge power. If charging is in progress, the power consumption will be adjusted according to the set lower limit P of the load power consumption.min_chg (Generally, it charges at 0). Another reason is that there are other auxiliary power generation equipment in the factory area at this time, such as photovoltaic, wind power and other new energy power generation equipment. Taking photovoltaic power generation equipment as an example, if photovoltaic power generation is excessive, the energy storage system will also charge according to P. min_chg This limits the charging power (usually to 0, meaning it won't charge when scheduled to discharge, which also applies to the first scenario).

[0071] Therefore, when a planned discharge is performed, P s ≤|P t -P e |;When scheduled for charging, P s ≤P max_t Therefore, to avoid situations where charging or discharging power exceeds the limits during operation, additional coefficients are typically set to limit the upper or lower limits, providing a certain buffer. For example, P... max_t When the load is 1000kW, an additional transformer load limit coefficient will be set. Taking a transformer load limit coefficient of 0.9 as an example, the maximum power consumption of the load in the energy storage system can only reach 1000kW*0.9=900kW, so as to avoid the situation where the transformer load exceeds the limit due to load power fluctuation.

[0072] In this embodiment, the method of allocating power to the integrated energy storage units in the energy storage system according to the revised planned power value includes average allocation; average allocation is to obtain the power value allocated to each integrated energy storage unit by multiplying the ratio of the maximum available power value of each integrated energy storage unit to the maximum available total power value of the entire station with the revised planned power value; the maximum available power value of each integrated energy storage unit is less than or equal to the maximum available total power value of the entire station.

[0073] Specifically, the corrected planned power value P is obtained. s Then, it needs to be distributed to each energy storage unit for execution. The method for achieving this even distribution is as follows:

[0074] Average allocation refers to distributing the revised planned power value evenly among all energy storage units. The set power of a single energy storage unit = total power target value * (maximum available power per unit PCS / maximum available total power), that is:

[0075]

[0076] Among them, P i The power to be ultimately allocated to this integrated energy storage unit; P s The revised planned power value; P max_i P represents the maximum available power of a certain energy storage unit. t This represents the maximum available total power of the entire station.

[0077] A usable integrated energy storage unit must meet at least the following two conditions:

[0078] Condition 1: The energy storage unit communicates normally with the EMU;

[0079] Condition 2: The energy storage unit is in a power-settable state, such as standby, charging, discharging, or operating mode. In this state, the charging or discharging power can be changed at any time. When discharging, the PCS (Power Control System) cannot be in a completely discharged state, or the current SOC of the energy storage unit's battery must be less than the lower limit. When charging, the PCS cannot be in a fully charged state, or the current SOC of the energy storage unit's battery must be greater than the upper limit. In these conditions, the energy storage unit is considered unusable. SOC (State of Charge) is the percentage of the battery's remaining capacity relative to its rated capacity. The charging and discharging algorithms are the same.

[0080] In particular, when P exists i >P max_i At that time, P i According to P max_i If the operation is not possible, the integrated energy storage unit should be set to 0 power.

[0081] In this embodiment, the method of allocating power to the integrated energy storage units in the energy storage system according to the corrected planned power value includes equalization allocation; equalization allocation includes:

[0082] The charging set power value allocated to each energy storage unit is obtained by multiplying the ratio of the remaining power value corresponding to the real-time SOC of each energy storage unit to the remaining power value corresponding to the average SOC of all energy storage units, the difference between the corrected planned power value and the sum of the available maximum power of all energy storage units operating at full power, and the ratio of the number of energy storage units operating at non-full power.

[0083] The discharge set power value allocated to each energy storage unit is obtained by multiplying the ratio of the real-time SOC of each energy storage unit to the average SOC of all energy storage units, the difference between the corrected planned power value and the sum of the available maximum power of all energy storage units operating at full power, and the ratio of the number of energy storage units operating at non-full power.

[0084] If the charging power setting value allocated to each energy storage unit meets the condition of being less than or equal to the maximum available power value of the corresponding energy storage unit, then each energy storage charging and discharging device will charge according to the allocated charging power setting value.

[0085] If the discharge setting power value allocated to each energy storage unit meets the condition of being less than or equal to the maximum available power value of the corresponding energy storage unit, then each energy storage charging and discharging device shall discharge according to the allocated discharge setting power.

[0086] Specifically, the aforementioned balanced allocation actually refers to distributing the revised planned power value to each energy storage unit based on the balanced power of each battery cluster's SOC, so that the SOC of each energy storage unit is kept as balanced as possible. This is beneficial for improving the system's charging and discharging quality and stability and extending battery life. The calculation method is as follows:

[0087]

[0088] Among them, P chg_i To set the charging power value allocated to each energy storage unit; P dischg_i The discharge set power value allocated to each energy storage unit; 1-SOC i This represents the remaining energy value corresponding to the real-time State of Charge (SOC) of a certain energy storage unit; 1-SOC avr The remaining energy value corresponding to the average SOC of all integrated energy storage units; N is the number of all available integrated energy storage units; n is the number of integrated energy storage units operating at full power; SOC i Real-time SOC of each energy storage unit; SOC avr The average SOC of all integrated energy storage units; P max_i This represents the maximum available power of a single energy storage unit operating at full power.

[0089] If the set charging power value or set discharging power value allocated to a certain energy storage unit does not meet the corresponding conditions, then the energy storage unit will operate at full power. At the same time, the number of energy storage units operating at full power will be updated, and then the calculation will be repeated in a balanced allocation manner until the set charging power value or set discharging power value no longer fails to meet the corresponding conditions, or until all energy storage units operate at full power.

[0090] Specifically, in the process of calculating and allocating power, if there is a set power consumption P... chg_i >P max_i Or there may be a set power P chg_i >P max_i In this case, the device follows P max_i Run at full power, and update n to the latest number of units running at full power. Then, substitute the n values ​​into the formula and calculate again until a new P value no longer appears in the calculation. chg_i >P max_i or P chg_i >P max_i The result or all integrated energy storage units are calculated to be operating at full power (N=n) until the result is achieved.

[0091] In this embodiment, the power allocation method described above is implemented through a host in the energy storage system; the integrated energy storage unit in the energy storage system includes an IoT-based energy management unit (i.e., an IoT-based EMU device). In other embodiments, other master-slave architectures of existing energy storage systems can also be used to implement the power allocation method described above.

[0092] Specifically, in this embodiment, each integrated energy storage unit of the energy storage system is equipped with a unit such as... Figure 3 The IoT-type EMU device shown is used to enable data access and control of other devices within its own cabinet. For example... Figure 4 As shown, the host is a single energy storage unit arbitrarily selected from all energy storage units. The IoT-based energy management unit in the host is used to collect data from the host; it is also used to communicate with the IoT-based energy management units of each slave unit to collect data from each slave unit and send the power allocation results of each slave unit obtained through power allocation; that is, as shown... Figure 5 As shown, any one energy storage unit can be selected as the master unit according to the actual configuration on site. The EMU device in the master unit is responsible for communicating with other slave EMUs, and is used by the master unit to perform tasks such as data acquisition and control, energy management and data and status statistics on the slave units.

[0093] In this embodiment, when a certain energy storage unit is selected as the host on site, in addition to configuring the communication parameters of the on-site gate meter and the on-site transformer parameters and other business-related attributes, there is also an automatic networking setting for the host and slave units. That is, after the host is selected, the host and each slave unit are automatically networked to establish communication between the host and each slave unit.

[0094] Automatic networking settings include: each slave device automatically connects to the host according to the default IP address of the maintenance network port configured on the host; the host searches for slave devices through timed broadcasts, and the slave devices respond to the host with their identity attributes according to the timed broadcast messages. The host verifies the legitimacy of each slave device based on its corresponding identity attributes and establishes a communication connection between the host and the verified slave devices.

[0095] Specifically, once a specific energy storage unit is selected as the master unit on-site, in addition to configuring business-related attributes such as on-site gateway meter communication parameters and on-site transformer parameters, there is also an automatic networking setup between the master and slave units. The communication establishment process is as follows:

[0096] ① Configure the default IP address of the host's maintenance network port for automatic connection of slave devices to the host;

[0097] ②After the host maintenance IP is deployed, the host communication module deployed on the slave will automatically connect to the host MQTT broker;

[0098] ③ The slave access module deployed on the host can search for slave devices via periodic broadcasts. After receiving the broadcast search message, the slave device responds to the host with its own attributes. The host verifies the legitimacy of the slave device. Once the verification is successful, communication can be established with the slave device and data transmission can be performed. This enables functions such as monitoring, controlling, and accessing slave device connection status, meeting the flexible racking requirements of different sites (the business function determines the number of available racks in real time and modifies the execution strategy in real time, such as the charging and discharging power allocation strategy).

[0099] like Figure 4 As shown, the methods for controlling certain devices within the slave device and collecting data from those devices after establishing a communication connection, as well as the methods for establishing the communication connection, are as follows:

[0100] 1) The EMU uses serial ports (RS485, RS232, CAN, etc.), network ports (TCP, UDP, etc.), and digital input (DI) to connect to data or signals from monitoring and control meters, grid connection meters, power conversion systems (PCS), battery management systems (BMS), temperature and humidity sensors, fire protection, access control, water immersion, and other equipment.

[0101] 2) Control the on / off state of running lights and fault lights through output (DO), and use serial port / network port communication to realize the start / stop, operation parameter modification and remote adjustment functions of PCS, BMS, air conditioning or liquid cooling, fire protection and other equipment;

[0102] 3) The gate meter is connected to the host EMU device, and the transformer voltage is collected through the host EMU device;

[0103] 4) Data such as current, power, and demand are used to calculate load tracking, demand control, and backflow prevention functions;

[0104] 5) The master-slave communication adopts the MQTT protocol, but can also adopt protocols such as IEC104, MODBUS-TCP, and IEC61850. The master EMU collects data such as charging and discharging voltage, current, power, and charging and discharging amount from the slave EMU for overall system data statistics and management. For example, it can realize data statistics functions such as overall system operating status, cumulative charging and discharging amount, total system power, and revenue, and realize management functions such as load tracking, energy regulation and distribution.

[0105] In addition, the IoT-enabled EMU device in the host is also used to communicate with the cloud to upload collected data or receive information from the cloud. The host communicates with the cloud using the MQTT protocol, but can also use protocols such as IEC104, MODBUS-TCP, and IEC61850. It uploads real-time data from the entire station, receives and executes cloud commands, and distributes relevant policies to the host and related devices on the slave devices. Terminals can remotely select and configure the host via the maintenance cloud or property management platform, and configure parameters such as communication parameters for on-site gateway meters and transformer capacity. The host automatically identifies and retrieves the number of slave devices within the local area network and establishes communication with them. Remote upgrades of the host program are supported via the maintenance cloud or property management platform. If a slave device does not have a SIM card and needs to communicate with the master station through the host, the slave device program and configuration can be upgraded through the host.

[0106] like Figure 5 As shown, the operation and maintenance management module is responsible for communicating with the operation and maintenance cloud or property management platform (i.e., communicating with the cloud), and also supports functions such as internal micro-application management, control operations, and file transfer. Specifically, this includes operations such as program start / stop, program upgrade, configuration update, file retrieval, and system restart. Notably, when the operation and maintenance cloud or property management platform needs to control the slave device through the host, the host must transmit the data transparently. Specifically, the operation and maintenance management module parses the commands from the operation and maintenance cloud or property management platform and transmits the commands to the relevant slave device through the slave device access module. Similarly, after receiving the command and processing it accordingly, the slave device replies to the host with the command result and transmits it transparently to the operation and maintenance cloud master station or property management platform.

[0107] Example of a power control correction system for energy storage systems

[0108] This embodiment provides a technical solution for a power control correction system for an energy storage system. The system includes a processor containing executable program instructions, which are used to implement the power control correction method for the energy storage system as described in the above embodiment.

[0109] Since the specific working mode and working principle of the power control correction system of the energy storage system in this embodiment have been described in detail in the above embodiment of the power control correction method of the energy storage system, they will not be repeated here.

[0110] It should be understood that the above-described specific embodiments of the present invention are merely illustrative or explanatory of the principles of the present invention, and do not constitute a limitation thereof.

Claims

1. A power control correction method for an energy storage system, characterized in that, The planned power value corresponding to the current time in the obtained planned curve is corrected according to the set load tracking algorithm, and the power is allocated to the energy storage charging and discharging equipment in the energy storage system according to the corrected planned power value. The specified load tracking algorithm includes: When the energy storage system plans to discharge, the smaller value between the load power consumption and the planned power, which are determined by the superimposed power corresponding to the grid discharge power and the total power of the energy storage discharge at the current moment, is taken in the direction of discharge to the load. The corrected planned power value is obtained by taking the larger value between the smaller value and the value of the set lower limit of power consumption in the direction of discharge to the load. When the energy storage system is scheduled to charge, the smaller of the positive value of the current corresponding monthly maximum power demand and the positive value of the transformer load limit corresponding to the power grid is taken. The larger of the difference between the smaller value and the value of the superimposed power in the direction of discharge to the load is compared with the value of the planned power in the direction of discharge to the load. Then, the corrected planned power value is obtained based on the smaller of the larger value and the value of the set discharge power limit in the direction of discharge to the load.

2. The power control correction method for an energy storage system according to claim 1, characterized in that, The methods for determining the load power consumption based on the superimposed power corresponding to the grid discharge power and the total energy storage discharge power obtained at the current moment include: taking the power after adjustment by the coefficient corresponding to the superimposed power as the load power consumption. If the direction of the superimposed power corresponding to the current grid discharge power and the total energy storage discharge power is towards the load discharge direction, then the coefficient corresponding to the superimposed power is determined to be a set discharge coefficient that is not less than 0 and less than 1; otherwise, the coefficient corresponding to the superimposed power is determined to be a set charging coefficient that is greater than or equal to 1.

3. The power control correction method for an energy storage system according to claim 1, characterized in that, The methods for determining the load power consumption based on the superimposed power corresponding to the grid discharge power and the total energy storage discharge power obtained at the current moment include: taking the power after adjustment by the coefficient corresponding to the superimposed power as the load power consumption. If the direction of the superimposed power corresponding to the grid discharge power and the total energy storage discharge power obtained at the current moment is towards the load discharge direction, then the coefficient corresponding to the superimposed power is determined to be the sum of the set discharge coefficient which is not less than 0 and less than 1 and the discharge power offset which is less than or equal to 0; otherwise, the coefficient corresponding to the superimposed power is determined to be the sum of the set charging coefficient which is greater than or equal to 1 and the charging power offset which is less than or equal to 0.

4. The power control correction method for an energy storage system according to any one of claims 1-3, characterized in that, The method of allocating power to the energy storage charging and discharging devices in the energy storage system according to the revised planned power value includes average allocation; the average allocation is to obtain the power value allocated to each energy storage charging and discharging device by multiplying the ratio of the maximum available power value of each energy storage charging and discharging device to the maximum available total power value of the energy storage system with the revised planned power value; the maximum available power value of each energy storage charging and discharging device is less than or equal to the maximum available total power value of the entire station.

5. The power control correction method for an energy storage system according to any one of claims 1-3, characterized in that, The method of allocating power to the energy storage charging and discharging devices in the energy storage system according to the revised planned power value includes equalization allocation; the equalization allocation includes: The charging set power value allocated to each energy storage charging and discharging device is obtained by multiplying the ratio of the remaining power value corresponding to the real-time SOC of each energy storage charging and discharging device to the remaining power value corresponding to the average SOC of all energy storage charging and discharging devices, and the product of the difference between the corrected planned power value and the sum of the available maximum power of all energy storage charging and discharging devices operating at full power and the ratio of the number of energy storage charging and discharging devices operating at non-full power. The discharge set power value allocated to each energy storage charging and discharging device is obtained by multiplying the ratio of the real-time SOC of each energy storage charging and discharging device to the average SOC of all energy storage charging and discharging devices, the difference between the corrected planned power value and the sum of the available maximum power of all energy storage charging and discharging devices operating at full power, and the ratio of the number of energy storage charging and discharging devices operating at non-full power. If the charging power setting value allocated to each energy storage charging and discharging device satisfies the condition that it is less than or equal to the maximum available power value of the corresponding energy storage charging and discharging device, then each energy storage charging and discharging device is charged according to the allocated charging power setting. If the discharge setting power value allocated to each energy storage charging and discharging device satisfies the condition that it is less than or equal to the maximum available power value of the corresponding energy storage charging and discharging device, then each energy storage charging and discharging device discharges according to the allocated discharge setting power. If there is a situation where the set charging power value or the set discharging power value allocated to a certain energy storage charging and discharging device does not meet the corresponding conditions, then the energy storage charging and discharging device will operate at full power. At the same time, the number of energy storage charging and discharging devices operating at full power will be updated. Then, the calculation will be repeated according to the balanced allocation method until the situation where the set charging power value or the set discharging power value does not meet the corresponding conditions no longer occurs in a certain calculation, or until all energy storage charging and discharging devices operate at full power.

6. The power control correction method for an energy storage system according to any one of claims 1-3, characterized in that, The methods for determining the maximum power demand for the current month include: if the maximum power demand for the current month is obtained, then the obtained maximum power demand for the current month is directly determined as the current maximum power demand for the current month; if the maximum power demand for the current month cannot be obtained, then the preset minimum monthly demand is determined as the current maximum power demand for the current month.

7. The power control correction method for an energy storage system according to any one of claims 1-3, characterized in that, The process of correcting the planned power value corresponding to the current time in the obtained planned curve according to the set load tracking algorithm, and allocating power to the energy storage charging and discharging devices in the energy storage system according to the corrected planned power value is realized by the host in the energy storage system; the energy storage charging and discharging devices in the energy storage system include a set Internet of Things energy management unit. The host is a single energy storage charging and discharging device arbitrarily selected from all energy storage charging and discharging devices. The IoT-based energy management unit in the host is used to collect data from the host; it is also used to communicate with the IoT-based energy management units of each slave device to collect data from each slave device and send the power allocation results of each slave device obtained by power allocation.

8. The power control correction method for an energy storage system according to claim 7, characterized in that, The IoT-enabled EMU device in the host is also used to communicate with the cloud to upload the collected data to the cloud or receive information sent down from the cloud.

9. The power control correction method for an energy storage system according to claim 7, characterized in that, Once the host is selected, automatic network configuration is performed on the host and each slave device to establish communication between the host and each slave device. The automatic networking setup includes: each slave device automatically connects to the host according to the default IP address of the maintenance network port configured by the host; the host searches for slave devices through timed broadcasts, the slave devices respond to the host with their identity attributes according to the timed broadcast messages, the host verifies the legitimacy of each slave device according to its corresponding identity attributes, and establishes a communication connection between the host and the verified slave devices.

10. A power control correction system for an energy storage system, comprising a processor, characterized in that, The processor is used to execute a computer program to implement the steps of the power control correction method for the energy storage system according to any one of claims 1-9.

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