Energy storage system control method, controller and energy storage system

Abstract

The invention discloses an energy storage system control method, a controller and an energy storage system, and relates to the technical field of energy storage systems.The energy storage system control method comprises the steps that the current load power and the preset electricity demand of the energy storage system are obtained, and the size relation between the current load power and the preset electricity demand is determined; determining the current working time period of the energy storage system, wherein the working time period comprises a charging time period, a standby time period and a discharging time period; according to the size relation and the working time period, target working modes of the energy storage system are determined, the energy storage system is controlled to work in the target working modes, and the target working modes comprise a charging mode, a standby mode and a discharging mode. The control method of the energy storage system aims at improving the peak load shifting capacity and the demand control capacity of the energy storage system.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage systems, and in particular to an energy storage system control method, a controller and an energy storage system. Background Art

[0002] The existing energy storage system has an imperfect peak-shaving and valley-filling control logic, which results in the failure to effectively reduce peak power consumption or even continue charging during periods when electricity rates are more expensive, and the failure to fully utilize valley electricity prices for charging or premature discharge during periods when electricity rates are cheaper. Therefore, the energy storage system has the problems of low peak-shaving and valley-filling capabilities and low demand control capabilities. Summary of the invention

[0003] The main purpose of the present invention is to propose an energy storage system control method, a controller and an energy storage system, aiming to improve the peak shaving and valley filling capability and demand control capability of the energy storage system.

[0004] To achieve the above object, the present invention proposes an energy storage system control method, wherein the energy storage system is used to supply power to a load; the energy storage system control method comprises:

[0005] Obtaining the current load power and the preset power demand of the energy storage system, and determining the magnitude relationship between the current load power and the preset power demand;

[0006] Determine the current working period of the energy storage system, wherein the working period includes a charging period, a standby period, and a discharging period;

[0007] According to the size relationship and the working period, a target working mode of the energy storage system is determined, and the energy storage system is controlled to work in the target working mode, wherein the target working mode includes a charging mode, a standby mode and a discharging mode.

[0008] In one embodiment, determining the target working mode of the energy storage system according to the size relationship and the working period includes:

[0009] When the working period is a charging period and the preset power demand is greater than the current load power, determining that the target working mode is a charging mode;

[0010] When the working period is a charging period and the preset power demand is not greater than the current load power, the target working mode is determined to be a discharging mode.

[0011] In one embodiment, when the working period is a charging period and the preset power demand is greater than the current load power, after determining that the target working mode is a charging mode, the method further includes:

[0012] When the energy storage system is connected to a transformer module, the energy storage system is controlled to operate in a charging mode at a first charging power, where the first charging power is the minimum value corresponding to the requested charging power of the battery management module in the energy storage system, the preset charging power of the energy storage system corresponding to the charging period, the remaining charging power of the transformer module, and the remaining power required by the public power grid;

[0013] When the energy storage system is not connected to a transformer module, the energy storage system is controlled to operate in a charging mode at a second charging power; the second charging power is a minimum value corresponding to the requested charging power of the battery management module in the energy storage system, the preset charging power of the energy storage system corresponding to the charging period, and the surplus power required by the public power grid;

[0014] In the case where the working period is a charging period and the preset power demand is not greater than the current load power, after determining that the target working mode is a discharging mode, the method further includes:

[0015] The energy storage system is controlled to operate in a discharge mode at a first discharge power, where the first discharge power is the minimum value corresponding to the installed capacity of the energy storage system, the current load power after taking the offset, the requested discharge power of the battery management module in the energy storage system, and the current load power exceeding the demand.

[0016] In one embodiment, determining the target working mode of the energy storage system according to the size relationship and the working period includes:

[0017] When the working period is a standby period and the preset power demand is greater than the current load power, determining that the target working mode is a standby mode;

[0018] When the working period is a standby period and the preset power demand is not greater than the current load power, the target working mode is determined to be a discharge mode.

[0019] In one embodiment, when the working period is a standby period and the preset power demand is not greater than the current load power, after determining that the target working mode is a discharge mode, the method further includes:

[0020] The energy storage system is controlled to operate in a discharge mode at a first discharge power, where the first discharge power is the minimum value corresponding to the installed capacity of the energy storage system, the current load power after taking the offset, the requested discharge power of the battery management module, and the current load power exceeding the demand.

[0021] In one embodiment, determining the target working mode of the energy storage system according to the size relationship and the working period specifically includes:

[0022] When the working period is a discharging period, determining that the target working mode of the energy storage system is a discharging mode;

[0023] According to the magnitude relationship, the discharge power of the energy storage system in the discharge mode is determined.

[0024] In one embodiment, when the energy storage system operates in the backflow prevention prohibition mode, determining the discharge power of the energy storage system in the discharge mode according to the magnitude relationship specifically includes:

[0025] When the preset power demand is greater than the current load power, determining the discharge power of the energy storage system in the discharge mode according to a first difference between the current discharge power and the previous discharge power;

[0026] When the preset power demand is not greater than the current load power, the energy storage system is controlled to operate in a discharge mode at a second discharge power, wherein the second discharge power is a larger value among the difference between the preset power demand and the current load power and the preset discharge power of the corresponding discharge period, the current load power, and the minimum value corresponding to the requested discharge power of the battery management module;

[0027] When the preset power demand is greater than the current load power, determining the discharge power of the energy storage system in the discharge mode according to a first difference between the current discharge power and the previous discharge power specifically includes:

[0028] When the first difference is greater than zero and not greater than a first preset difference, determining that the current discharge power is equal to the previous discharge power;

[0029] In the case where the first difference is greater than the first preset difference, the energy storage system is controlled to operate in a discharge mode at a third discharge power, where the third discharge power is the smaller of the current load power and the requested discharge power of the battery management module minus the difference between the discharge power last sent by the energy storage system and the last discharge power sent by the energy storage system multiplied by the convergence coefficient;

[0030] When the first difference is less than zero, the energy storage system is controlled to operate in a discharge mode at a fourth discharge power, where the fourth discharge power is the minimum value corresponding to the current load power, the preset discharge power corresponding to the discharge period, and the requested discharge power of the battery management module.

[0031] In one embodiment, when the energy storage system operates in the backflow prevention enabling mode, determining the discharge power of the energy storage system in the discharge mode according to the magnitude relationship specifically includes:

[0032] When the preset power demand is greater than the current load power after taking the offset, determining the discharge power of the energy storage system in the discharge mode according to a first difference between the current discharge power and the previous discharge power;

[0033] In the case where the preset power demand is not greater than the current load power after taking the offset, the energy storage system is controlled to operate in a discharge mode at a fifth discharge power, wherein the fifth discharge power is the larger value of the difference between the preset power demand and the current load power and the preset discharge power of the corresponding discharge period, the current load power after taking the offset, and the minimum value corresponding to the requested discharge power of the battery management module;

[0034] When the preset power demand is greater than the current load power after taking the offset, determining the discharge power of the energy storage system in the discharge mode according to a first difference between the current discharge power and the previous discharge power specifically includes:

[0035] When the first difference is greater than zero and not greater than a first preset difference, determining that the current discharge power is equal to the previous discharge power;

[0036] In the case where the first difference is greater than the first preset difference, the energy storage system is controlled to operate in a discharge mode at a sixth discharge power, wherein the sixth discharge power is a value obtained by multiplying the smaller value of the current load power after the offset and the requested discharge power of the battery management module minus the discharge power last issued by the energy storage system by a smoothing coefficient and adding the difference to the discharge power last issued by the energy storage system;

[0037] When the first difference is less than zero, the energy storage system is controlled to operate in a discharge mode at a seventh discharge power, where the seventh discharge power is the minimum value corresponding to the current load power after taking the offset, the preset discharge power corresponding to the discharge period, and the requested discharge power of the battery management module.

[0038] The present invention also provides a controller, which is used to implement the energy storage system control method as described in any one of the above.

[0039] The present invention also provides an energy storage system, which includes the controller as described above.

[0040] The present invention provides a method for controlling an energy storage system, which can determine the optimal target operating mode (charging mode, standby mode or discharge mode) of the energy storage system by utilizing the size relationship between the current load power and the preset power demand, and combining the working period (charging, standby or discharge period) of the energy storage system. For example, during the charging period, if the size relationship indicates that the current load power is greater than the preset power demand, then even during the charging period, it is necessary to enter the discharge mode to prevent the demand from exceeding the standard and reduce the peak power consumption; similarly, during the standby period, if the size relationship indicates that the current load power is greater than the preset power demand, then even during the standby period, it is necessary to enter the discharge mode to quickly reduce the total power consumption and avoid an increase in the demand electricity charge.

[0041] Therefore, by comparing the relationship between the current load power and the preset power demand at different time periods, the appropriate target operating mode can be determined, thereby improving the peak shaving and valley filling capabilities and demand control capabilities of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0043] Figure 1 A flow chart of a first embodiment of the energy storage system control method provided by the present invention;

[0044] Figure 2 A flow chart of a second embodiment of the energy storage system control method provided by the present invention;

[0045] Figure 3 A flow chart of a third embodiment of the energy storage system control method provided by the present invention;

[0046] Figure 4 A flowchart of a fourth embodiment of the energy storage system control method provided by the present invention;

[0047] Figure 5 A flowchart of a fifth embodiment of the energy storage system control method provided by the present invention;

[0048] Figure 6 A flow chart of a sixth embodiment of the energy storage system control method provided by the present invention;

[0049] Figure 7 A flow chart of a seventh embodiment of the energy storage system control method provided by the present invention;

[0050] Figure 8A flow chart of an eighth embodiment of the energy storage system control method provided by the present invention;

[0051] Fig. 9 A flow chart of a ninth embodiment of the energy storage system control method provided by the present invention;

[0052] Fig.10 A flowchart of a tenth embodiment of the energy storage system control method provided by the present invention;

[0053] Fig.11 A flow chart of an eleventh embodiment of the energy storage system control method provided by the present invention;

[0054] Fig.12 This is a flow chart of the twelfth embodiment of the energy storage system control method provided by the present invention.

[0055] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0058] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0059] It should be noted that, in this article, step codes such as S100, S200, etc. are used for the purpose of expressing the corresponding content more clearly and concisely, and do not constitute a substantial limitation on the sequence. When implementing the step, those skilled in the art may execute S200 first and then S100, etc., but these should all be within the scope of protection of this application.

[0060] There are many types of electricity prices adopted by countries around the world, but there are four main forms of basic electricity price systems: fixed-rate electricity price system, electricity price system based on electricity consumption (or single electricity price system), time-of-use electricity price system and two-part electricity price system. The fixed-rate electricity price system is the oldest electricity price system. It is not charged according to the monthly electricity consumption, but is charged monthly according to the equipment capacity and electricity consumption time. The electricity price system calculates the electricity fee based on the electricity consumption, which is more reasonable than the fixed-rate electricity price system. The characteristics of time-of-use electricity price are to regulate the peak electricity consumption and encourage the use of electricity during the off-peak period to improve the system load characteristics. The two-part electricity price system is a system that combines the basic electricity price corresponding to the capacity and the electricity price corresponding to the electricity consumption to determine the electricity price. Large industrial electricity consumption adopts a two-part electricity price, which consists of three parts: the basic electricity price, the electricity price and the power factor adjustment fee. The basic electricity price refers to the electricity price calculated based on the user's receiving transformer (kilovolt-ampere) or maximum demand (kilowatt-hour); the kilowatt-hour electricity price refers to the electricity price calculated based on the user's actual electricity consumption (kilowatt-hour); the power factor adjustment electricity fee refers to the electricity fee that is reduced or increased based on the user's monthly weighted average power factor.

[0061] In view of the time-of-use electricity price system, there are different electricity fee standards at different times. Therefore, the corresponding energy storage system is also set with charging period, standby period and discharge period to cope with the time-of-use electricity price system, ensuring that the best power management decision is made in different electricity price periods, so as to minimize costs and maximize energy efficiency. Specifically, during the off-peak electricity price period (such as at night), the energy storage system will give priority to the charging mode, make full use of cheap electricity for charging, and reserve energy for the subsequent peak period; during the peak electricity price period (such as daytime working hours), the system switches to the discharge mode, releasing the stored electricity to reduce the dependence on high-priced grid electricity, effectively reducing peak electricity consumption and demand electricity charges; for the flat electricity price period, it is flexibly adjusted according to the actual load situation, or remains in standby state for further instructions.

[0062] However, if a plant plans to install an energy storage system to implement peak-to-valley arbitrage, the traditional energy storage system does not have a demand control logic and the logic is too simple, which causes charging or no discharge when the demand is high, which indirectly causes a large increase in demand electricity charges, resulting in the user's actual electricity charges not being reduced or even increasing. Therefore, the traditional energy storage system has the problem of low peak-to-valley arbitrage and demand control capabilities.

[0063] In order to solve the above problems, the present invention proposes a method for controlling an energy storage system. It can be understood that the energy storage system is used to supply power to the load; thus, the relationship between the load power change and the demand setting value becomes an important factor in optimizing control. Through precise monitoring and dynamic adjustment, the method ensures that the energy storage system can make optimal decisions in different time periods, thereby achieving efficient peak shaving and valley filling and demand control.

[0064] It should be noted that the current load power refers to the total power actually consumed by all electrical devices at the user end at a certain moment, reflecting the user's real-time power demand at the current time point, and is usually obtained in real time through smart meters or power monitoring devices installed on the user side. The preset power demand refers to the maximum allowable power consumption set by the user or power company to avoid high demand charges. It can be an upper limit value determined based on historical power consumption data, contractual agreements, or the user's own management goals.

[0065] like Figure 1 As shown, in one embodiment, the energy storage system control method includes steps S100 to S300.

[0066] In this embodiment, step S100, the current load power and the preset power demand of the energy storage system are obtained, and the magnitude relationship between the current load power and the preset power demand is determined.

[0067] It is understandable that the current load power (P_load) and the preset power demand (P_demand) of the energy storage system are first obtained, and the size relationship between the two is determined. This process is the basis of the entire control logic and determines the specific operation of the energy storage system at any time. For example, the current load power is close to or exceeds the preset power demand, which may indicate that a high electricity price period is about to occur or that the capacity limit specified in the contract is exceeded. Therefore, this process helps to warn of potential problems in advance and is the basis for achieving efficient peak shaving and demand control.

[0068] It should be explained that real-time collection of gateway table data can realize dynamic adjustment of the energy storage system discharge power, achieve the goal of backflow prevention through flexible software control strategies, and reduce the system hardware investment cost.

[0069] In this embodiment, step S200, determining the current working period of the energy storage system, wherein the working period includes a charging period, a standby period and a discharging period.

[0070] It can be understood that the current working period of the energy storage system is determined, and the working period includes the charging period, the standby period and the discharging period. Each working period corresponds to different electricity price levels and electricity demand characteristics. For example, the charging period usually corresponds to the valley electricity price, while the discharging period corresponds to the peak electricity price. By identifying the current working period, the corresponding control strategy can be formulated to ensure that the charging or discharging operation is performed at the appropriate time.

[0071] In this embodiment, step S300, according to the size relationship and the working period, the target working mode of the energy storage system is determined, and the energy storage system is controlled to work in the target working mode, and the target working mode includes a charging mode, a standby mode and a discharging mode.

[0072] It is understandable that the system determines the target working mode of the energy storage system based on the size relationship between the current load power and the preset power demand determined in step S100 and the working period confirmed in step S200. For example, during the charging period, if the size relationship indicates that the current load power (P_load) is greater than the preset power demand (P_demand), then even during the charging period, it is necessary to enter the discharge mode to prevent the demand from exceeding the standard and reduce the peak power consumption; similarly, during the standby period, if the size relationship indicates that the current load power (P_load) is greater than the preset power demand (P_demand), then even during the standby period, it is necessary to enter the discharge mode to quickly reduce the total power consumption and avoid an increase in the demand electricity charge. This flexible response mechanism can significantly improve the operating efficiency of the energy storage system, ensure that the best decision can be made under any circumstances, and achieve efficient peak shaving and demand control.

[0073] However, in existing energy storage systems, during off-peak electricity price periods, the system will prioritize charging mode to make full use of low-priced electricity; and during peak electricity price periods, it will switch to discharge mode to release stored electricity to reduce dependence on high-priced grid electricity. This results in failure to fully consider the impact of demand control and load fluctuations, and may continue to charge or fail to discharge in time when demand is high, which indirectly causes an increase in demand charges, and even increases the user's actual electricity charges instead of reducing them, and has low peak-shaving and valley-filling capabilities.

[0074] Therefore, in this embodiment, by utilizing the magnitude relationship between the current load power and the preset power demand, and combining the working period (charging, standby or discharging period) of the energy storage system, the optimal target working mode (charging mode, standby mode or discharging mode) of the energy storage system can be determined. In this way, it is not simply charging mode during the charging period, but the target working mode is determined according to the magnitude relationship during the charging period. For example, during the charging period, if the current load power (P_load) is greater than the preset power demand (P_demand), even in the off-peak electricity price period, the system will switch to the discharge mode to avoid demand exceeding the standard, thus avoiding the increase in demand electricity charges and power waste caused by improper charging and discharging operations in traditional energy storage systems, thereby improving the peak-shaving and valley-filling capabilities and demand control capabilities of the energy storage system.

[0075] In one embodiment, step S300 also includes step S310 and step S320.

[0076] In this embodiment, if Figure 2 and Fig.10 As shown, in step S310, when the working period is a charging period and the preset power demand is greater than the current load power, the target working mode is determined to be a charging mode.

[0077] In this embodiment, in step S320, when the working period is a charging period and the preset power demand is not greater than the current load power, the target working mode is determined to be a discharging mode.

[0078] It is understandable that step S310 stipulates that when the working period is a charging period and the preset power demand is greater than the current load power, the target working mode is determined to be a charging mode, that is, in the off-peak electricity price period, if the current power demand (current load power) is relatively low and does not approach or exceed the set maximum allowable power consumption (preset power demand), the energy storage system will make full use of this opportunity to charge and reserve cheap electricity for subsequent use. Step S320 is for another situation, that is, when the working period is a charging period but the preset power demand is not greater than the current load power, the target working mode is determined to be a discharge mode. This shows that even in the off-peak electricity price period, if the current load has approached or exceeded the set demand threshold, the system will give priority to discharge to reduce the total power demand and avoid triggering high demand electricity charges. In this way, the energy storage system can flexibly adjust its charging and discharging strategies under different circumstances to ensure that not only the effect of peak shaving and valley filling is achieved, but also the demand electricity charge is effectively controlled, and the economic benefits brought by the price difference are maximized, thereby improving the peak shaving and valley filling capability and demand control capability.

[0079] In one embodiment, if Figure 3 and Fig.10As shown, step S310 also includes step S311 and step S312.

[0080] First, explain the following parameters: 1. The requested charging power (P_ask) of the battery management module: the maximum charging power allowed by the battery management system in the energy storage system according to the battery health status and safety restrictions. 2. The preset charging power (P_set) of the energy storage system corresponding to the charging period: the maximum charging power allowed in the current charging period set for the energy storage system to ensure that it does not exceed the capacity limit of the energy storage system. 3. The remaining charging power of the transformer module (η×S-(P_tra+P_bat)): taking into account the actual load of the transformer, ensure that the charging operation does not cause the transformer to be overloaded. 4. The remaining power demand of the public grid (P_demand-P_load): ensure that the charging operation does not cause the total power demand to exceed the demand setting value of the public grid to avoid triggering high demand electricity charges. Among them, η is the load rate of the transformer at the energy storage grid connection point; S is the transformer capacity at the energy storage grid connection point; P_tra is the real-time active power of the transformer, positive value for power consumption, negative value for power transmission; P_bat is the real-time active power of the energy storage, positive value for discharge, negative value for charging.

[0081] In this embodiment, step S311, when the energy storage system is connected to a transformer module, controls the energy storage system to operate in a charging mode with a first charging power, wherein the first charging power is the minimum value corresponding to the requested charging power of the battery management module in the energy storage system, the preset charging power of the energy storage system corresponding to the charging period, the remaining charging power of the transformer module, and the remaining power demanded by the public power grid.

[0082] In this embodiment, step S312, when the energy storage system is not connected to a transformer module, controls the energy storage system to operate in a charging mode at a second charging power; the second charging power is the minimum value corresponding to the requested charging power of the battery management module in the energy storage system, the preset charging power of the energy storage system corresponding to the charging period, and the surplus power demanded by the public power grid.

[0083] First charging power = min{P_ask, P_set, η×S-(P_tra+P_bat), P_demand-P_load};

[0084] The second charging power = min{P_ask, P_set, P_demand-P_load}.

[0085] It can be understood that the second charging power is the minimum value of the corresponding three parameters, and the charging power ensures that the energy storage system can operate within a safe and economical range without connecting to the transformer module. In addition, the first charging power has a parameter greater than the second charging power by the remaining charging power of the transformer module, so that the risk of transformer overload due to excessive charging power can be avoided, ensuring the stability of power supply and the safety of equipment.

[0086] In one embodiment, step S320 also includes step S321. In this embodiment, step S321 controls the energy storage system to operate in a discharge mode at a first discharge power, wherein the first discharge power is the minimum value corresponding to the installed capacity of the energy storage system, the current load power after taking the offset, the requested discharge power of the battery management module in the energy storage system, and the current load power exceeding the demand.

[0087] First, explain the following parameters: 1. Installed capacity of the energy storage system (P_total): The maximum output capacity of the energy storage system, that is, its designed maximum discharge power. Ensure that the physical limitations of the system are not exceeded to avoid overloading or damage to the equipment. 2. The current load power after taking the offset (P_load×n1): Take into account the actual load conditions and adjust the current load power according to a certain offset (n1). This helps to match the current power demand more accurately while leaving a certain safety margin. 3. The requested discharge power (P_ask) of the battery management module: The maximum allowable discharge power calculated by the battery management system (BMS) of the energy storage system based on factors such as the health status, temperature and state of charge (SOC) of the battery. 4. The current load power that exceeds the demand (P_load-P_demand): refers to the part of the current load power that exceeds the preset power demand.

[0088] The first discharge power = min{P_total, P_load×n1, P_ask, P_load-P_demand}.

[0089] It is understandable that by selecting the minimum value of the above four parameters as the first discharge power, the system can ensure that all equipment operates within a safe range and avoid the risk of overload operation. At the same time, it can maximize the use of energy storage resources, reduce dependence on high-priced grid electricity, avoid the increase in demand electricity charges, and minimize costs. It should be explained that the discharge mode at this time only needs to reduce the current load power on the gateway side to below the preset power demand.

[0090] In one embodiment, if Figure 4 and Fig.11 As shown, step S300 also includes step S330 and step S340.

[0091] In this embodiment, in step S330, when the working period is a standby period and the preset power demand is greater than the current load power, the target working mode is determined to be a standby mode.

[0092] In this embodiment, in step S340, when the working period is a standby period and the preset power demand is not greater than the current load power, the target working mode is determined to be a discharge mode.

[0093] It is understandable that step S300 is further subdivided into step S330 and step S340. Specifically, step S330 stipulates that when the working period is a standby period and the preset power demand is greater than the current load power, the target working mode is determined to be a standby mode. This means that if the current load power is relatively low and does not approach or exceed the preset power demand, the energy storage system will remain in a standby state and will not perform charging and discharging operations, thereby avoiding unnecessary energy loss and equipment wear. Step S340 is for another situation, that is, when the working period is a standby period but the preset power demand is not greater than the current load power, the target working mode is determined to be a discharge mode. This shows that even in the standby period, if the current load has approached or exceeded the set demand threshold, the system will give priority to discharge to reduce the total power demand and avoid triggering high demand charges. Through these two subdivided steps, the energy storage system can flexibly adjust its working mode in different situations to ensure that not only the effect of peak shaving and valley filling is achieved, but also the demand charge is effectively controlled.

[0094] In this embodiment, step S330 also includes step S331. Step S331, control the energy storage system to operate in a discharge mode at a first discharge power, wherein the first discharge power is the minimum value corresponding to the installed capacity of the energy storage system, the current load power after taking the offset, the requested discharge power of the battery management module, and the current load power exceeding the demand.

[0095] The first discharge power = min{P_total, P_load×n1, P_ask, P_load-P_demand}.

[0096] In one embodiment, if Figure 5 and Fig.12 As shown, step S300 also includes step S350 and step S360.

[0097] In this embodiment, in step S350, when the working period is a discharging period, it is determined that the target working mode of the energy storage system is a discharging mode.

[0098] It is understandable that step S350 stipulates that when the working period is the discharge period, the system will determine that the target working mode of the energy storage system is the discharge mode. The discharge period usually corresponds to the peak electricity price period, when the power grid price is high, and the cost of users relying on high-priced electricity also increases accordingly. By switching to the discharge mode, the energy storage system can release the previously stored low-priced electricity to meet the current electricity demand, thereby reducing dependence on high-priced grid electricity and significantly reducing electricity bills. In addition, the discharge mode can also help to smooth the peak and fill the valley, smooth the load curve, avoid grid overload, and ensure the stability and reliability of power supply. Therefore, step S350 ensures that during the peak electricity price period, the energy storage system can give full play to its peak shaving effect, minimize costs and maximize energy efficiency.

[0099] In this embodiment, step S360, based on the magnitude relationship, the discharge power of the energy storage system in the discharge mode is determined.

[0100] It can be understood that determining the discharge power according to the relationship between the current load power (P_load) and the preset power demand (P_demand) can ensure that the energy storage system makes the best decision under different working conditions and realizes efficient power management and cost control. Specifically, through these two parameters, the system can flexibly adjust the output power during the discharge period to avoid exceeding the demand setting value, thereby preventing the generation of high demand electricity charges. For example, when the load approaches or exceeds the preset power demand, the system will increase the discharge power to quickly reduce the total power demand; when the load is far below the demand setting value, a smaller discharge power can be selected to meet the current power demand without wasting excess power resources. In this way, step S360 not only optimizes the energy utilization efficiency, but also improves the stability and safety of the power supply, and ultimately achieves effective control of user electricity charges and long-term reliability of the system.

[0101] In one embodiment, if Figure 6 and Fig.12 As shown, step S360 includes step S361 and step S362.

[0102] Among them, step S361 and step S362 are for the anti-backflow prohibition mode. In the anti-backflow prohibition mode, reverse current exists and there is no need to consider the anti-backflow coefficient. Maximum discharge is sufficient.

[0103] In this embodiment, step S361, when the preset power demand is greater than the current load power, the discharge power of the energy storage system in the discharge mode is determined according to a first difference between the current discharge power and the previous discharge power.

[0104] It is understandable that step S361 stipulates that when the preset power demand (P_demand) is greater than the current load power (P_load), the system will determine the discharge power of the energy storage system in the discharge mode according to the first difference between the current discharge power and the previous discharge power, thereby ensuring that the system can respond flexibly under low load conditions and avoid unnecessary high-power discharge operations. In some examples, by judging the power transmission values ​​​​before and after 2 times, if the first difference between the power transmission values ​​​​before and after 2 times is within the set threshold range, no new power control value will be issued, avoiding the frequent remote adjustment command transmission from affecting the stability of the system. Among them, the specific value of the predetermined threshold is not limited here and can depend on the actual application. In this way, the system can smoothly transition to the required discharge level, prevent sudden changes in power supply, and ensure the stability and economy of power supply.

[0105] In this embodiment, step S362, when the preset power demand is not greater than the current load power, the energy storage system is controlled to operate in a discharge mode at a second discharge power, wherein the second discharge power is a larger value of the difference between the preset power demand and the current load power and the preset discharge power of the corresponding discharge period, the current load power, and the minimum value corresponding to the requested discharge power of the battery management module.

[0106] Second discharge power=min{max{P_load-P_demand, P_set}, P_load, P_ask}.

[0107] It can be understood that by taking the larger value between the difference between the preset power demand and the current load power and the preset discharge power of the corresponding discharge period, the power demand exceeding the demand can be preferentially met even when the load is high.

[0108] It can be understood that by selecting the minimum value of the above three parameters as the second discharge power, the system can accurately adjust the discharge power when the load approaches or exceeds the demand setting value, ensuring that the total power demand is met while avoiding triggering high demand electricity charges. At the same time, it can avoid the discharge power being too large and exceeding the actual load usage and the maximum output capacity of the energy storage system at this time.

[0109] In one embodiment, if Figure 7 and Fig.12 As shown, step S361 includes steps S3611 to S3613.

[0110] In this embodiment, step S3611, when the first difference is greater than zero and not greater than a first preset difference, determining that the current discharge power is equal to the previous discharge power.

[0111] It is understandable that step S3611 stipulates that when the first difference is greater than zero and not greater than the first preset difference, the system will determine that the current discharge power is equal to the previous discharge power. That is, if the change in discharge power is very small and is not enough to trigger a significant adjustment demand, the system will choose to keep the current discharge power unchanged. This helps to avoid power supply fluctuations and equipment wear caused by frequent small adjustments.

[0112] In this embodiment, step S3612, when the first difference is greater than the first preset difference, the energy storage system is controlled to operate in a discharge mode at a third discharge power, wherein the third discharge power is a smaller value between the current load power and the requested discharge power of the battery management module minus the difference between the discharge power last sent by the energy storage system multiplied by the convergence coefficient, and the resultant value is added to the discharge power last sent by the energy storage system.

[0113] It can be understood that the third discharge power = [(the smaller value of the current load power and the requested discharge power of the battery management module) - (the discharge power last sent by the energy storage system)] × n3 + the discharge power last sent by the energy storage system. Step S3612 ensures that when the load changes greatly, the system can respond quickly and adjust the discharge power to meet the new power demand. For example, if the current load power is 300kW, the requested discharge power of the battery management module is 250kW, the last discharge power sent is 50kW, and the first difference exceeds the preset value, the system will calculate the new discharge power as (250kW-50kW) × n3 + 50kW. In this way, slow discharge can be achieved to prevent oscillation (when the energy storage system is charging and discharging, the calculated power value is directly sent, which is easy to cause system oscillation). At the same time, rapid discharge can prevent excessive backflow and waste of energy storage.

[0114] The third discharge power = [min{P_load, P_ask} - P_last] × n3 + P_last.

[0115] In this embodiment, step S3613, when the first difference is less than zero, controls the energy storage system to operate in a discharge mode at a fourth discharge power, where the fourth discharge power is the minimum value corresponding to the current load power, the preset discharge power corresponding to the discharge period, and the requested discharge power of the battery management module.

[0116] The fourth discharge power=min{P_load, P_set, P_ask}.

[0117] It is understandable that when the first difference is less than zero, it means that the current load power has dropped, and the system needs to reduce the discharge power to avoid excessive discharge or waste of power resources, and to avoid excessive reverse flow causing waste of energy storage power, the discharge power needs to be quickly reduced, and no longer step-by-step adjustment is made, but the discharge power is directly sent down. Among them, for the discharge power sent down in other cases, step-by-step adjustment is adopted to avoid system oscillation.

[0118] In one embodiment, if Figure 8 and Fig.12 As shown, when the energy storage system operates in the anti-backflow enabling mode, step S360 includes step S363 and step S364.

[0119] Among them, step S363 and step S364 are for the anti-backflow enabling mode, that is, power transmission to the grid is not allowed, so the anti-backflow coefficient n1 needs to be taken into consideration when determining the discharge power.

[0120] In this embodiment, step S363, when the preset power demand is greater than the current load power after taking the offset, the discharge power of the energy storage system in the discharge mode is determined according to a first difference between the current discharge power and the previous discharge power.

[0121] In this embodiment, step S364, when the preset power demand is not greater than the current load power after taking the offset, controls the energy storage system to operate in a discharge mode at a fifth discharge power, wherein the fifth discharge power is the larger value of the difference between the preset power demand and the current load power and the preset discharge power of the corresponding discharge period, the current load power after taking the offset (P_load×n1), and the minimum value corresponding to the requested discharge power of the battery management module.

[0122] The fifth discharge power=min{max{P_load-P_demand, P_set}, P_load×n1, P_ask}.

[0123] It is understandable that if the demand setting value (P_demand) ≤ the actual current load power (P_load*n1) after adding the offset, it means that the load is large and has exceeded the demand setting value, and rapid discharge is required to reduce the demand. Through the fifth discharge power, it is possible to avoid the discharge power being too large and exceeding the actual load usage and the maximum output capacity of the energy storage system at this time.

[0124] In one embodiment, if Fig. 9 and Fig.12 As shown, step S363 also includes steps S3631 to S3633.

[0125] It is understandable that if the demand setting value (P_demand) is greater than the actual current load power (P_load*n1) after adding the offset, that is, the current load power at this time does not exceed the demand setting value, a step-by-step power increase discharge can be performed at this time.

[0126] In this embodiment, step S3631, when the first difference is greater than zero and not greater than a first preset difference, determining that the current discharge power is equal to the previous discharge power.

[0127] It is understandable that when the first difference is greater than zero and not greater than the first preset difference, it is determined that the current discharge power is equal to the previous discharge power. This means that if the change in discharge power is very small and is not enough to trigger a significant adjustment demand, the system will choose to keep the current discharge power unchanged. In this way, power supply fluctuations and equipment wear caused by frequent small adjustments can be avoided, ensuring the stability of power supply and safe operation of equipment.

[0128] In this embodiment, step S3632, when the first difference is greater than the first preset difference, the energy storage system is controlled to operate in a discharge mode at a sixth discharge power, wherein the sixth discharge power is a value obtained by multiplying the smaller value of the current load power (P_load×n1) after the offset and the requested discharge power of the battery management module minus the discharge power last sent by the energy storage system, multiplied by a smoothing coefficient, and added to the discharge power last sent by the energy storage system.

[0129] It can be understood that by introducing the anti-backflow coefficient n1, it is ensured that the discharge power will not exceed the current load power to prevent the backflow phenomenon. At the same time, the use of the smoothing coefficient n3 makes the power adjustment more stable and reduces the impact on the power grid and equipment.

[0130] Optionally, the first preset difference in the above multiple embodiments is specifically equal to p_total×n2.

[0131] The sixth discharge power = [min{P_load×n1, P_ask}-P_last]×n3+P_last, wherein n3 is the power adjustment and collection coefficient (ie, the smoothing coefficient), n1 is the anti-backflow coefficient, and P_last is the discharge power sent last time.

[0132] It can be understood that if the PCS planned power delivery value minus the last PCS power delivery value (ie, ΔP) ≥ 0, it means that the load has increased. If the increase is not large, that is, ΔP ≤ P_total*n2, there is no need to deliver a new power setting value at this time, and continue to execute the power value delivered last time; but if the increase is relatively large, resulting in ΔP>P_total*n2, then it is necessary to deliver the sixth discharge power at this time to discharge slowly and prevent oscillation.

[0133] In this embodiment, step S3633, when the first difference is less than zero, controls the energy storage system to operate in a discharge mode at a seventh discharge power, wherein the seventh discharge power is the minimum value corresponding to the current load power after taking the offset, the preset discharge power corresponding to the discharge period, and the requested discharge power of the battery management module.

[0134] The seventh discharge power = min{P_load×n1, P_set, P_ask}, wherein n1 is the backflow prevention coefficient.

[0135] It is understandable that if the PCS planned power delivery value minus the last PCS power delivery value (ie, ΔP) is less than 0, it means that the load has decreased. To avoid reverse flow, the discharge power needs to be reduced quickly instead of step-by-step adjustment.

[0136] The present invention also provides a controller. It should be noted that the controller is used to implement the energy storage system control method. The controller provided in the embodiment of the present invention can improve the peak shaving and valley filling capability and demand control capability of the energy storage system. Compared with the prior art, the beneficial effects of the controller provided in the embodiment of the present application are the same as the beneficial effects of the energy storage system control method provided in the above embodiment, which will not be repeated here.

[0137] The present invention also provides an energy storage system, which includes the above-mentioned controller. Compared with the prior art, the beneficial effects of the energy storage system provided by the embodiment of the present application are the same as the beneficial effects of the energy storage system control method provided by the above-mentioned embodiment, which will not be repeated here.

[0138] It can be understood that through the above-mentioned controller, it is possible to collect system data in all directions, including power consumption data at gateway points, transformer operation data, energy storage system data, etc. After comprehensive judgment and analysis, a more optimized corresponding control logic can be executed. At least the following beneficial effects can be brought about: (1) Combining peak shaving and valley filling with demand control can not only realize peak-valley arbitrage, but also reduce user demand electricity charges. Revenue management is carried out at two levels to maximize revenue, reduce customer electricity costs, and have a positive impact on the stability of the public power grid; (2) According to the power calculation value, remote control instructions are issued in a step-by-step manner to avoid system oscillations; (3) By judging the power issuance values ​​before and after twice, if the difference is within the set threshold range, no new power control value will be issued, avoiding the impact of frequent remote control instruction issuance on system stability; (4) Real-time collection of gateway table data can realize dynamic (5) Support the access of transformer operation data to effectively avoid overload of transformer during charging period; (6) Diversified and open parameter setting options are available, which can be flexibly configured for different working conditions and scenarios, and have strong adaptability to different scenarios; (7) The control logic is designed according to different working conditions and scenarios, with powerful functions and low failure rate; (8) One-stop service for the whole life cycle, relying on the energy storage cloud platform, creates an integrated intelligent operation and maintenance of "online monitoring + offline inspection", which does not require human participation and realizes "unmanned operation".

[0139] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for controlling an energy storage system, characterized in that: The energy storage system is used to supply power to a load; the energy storage system control method comprises: Obtaining the current load power and the preset power demand of the energy storage system, and determining the magnitude relationship between the current load power and the preset power demand; Determine the current working period of the energy storage system, wherein the working period includes a charging period, a standby period, and a discharging period; According to the size relationship and the working period, a target working mode of the energy storage system is determined, and the energy storage system is controlled to work in the target working mode, wherein the target working mode includes a charging mode, a standby mode and a discharging mode.

2. The energy storage system control method according to claim 1, characterized in that: Determining the target working mode of the energy storage system according to the size relationship and the working period includes: When the working period is a charging period and the preset power demand is greater than the current load power, determining that the target working mode is a charging mode; When the working period is a charging period and the preset power demand is not greater than the current load power, the target working mode is determined to be a discharging mode.

3. The energy storage system control method according to claim 2, characterized in that: In the case where the working period is a charging period and the preset power demand is greater than the current load power, after determining that the target working mode is a charging mode, the method further includes: When the energy storage system is connected to a transformer module, the energy storage system is controlled to operate in a charging mode at a first charging power, where the first charging power is the minimum value corresponding to the requested charging power of the battery management module in the energy storage system, the preset charging power of the energy storage system corresponding to the charging period, the remaining charging power of the transformer module, and the remaining power required by the public power grid; When the energy storage system is not connected to a transformer module, the energy storage system is controlled to operate in a charging mode at a second charging power; the second charging power is a minimum value corresponding to the requested charging power of the battery management module in the energy storage system, the preset charging power of the energy storage system corresponding to the charging period, and the surplus power required by the public power grid; In the case where the working period is a charging period and the preset power demand is not greater than the current load power, after determining that the target working mode is a discharging mode, the method further includes: The energy storage system is controlled to operate in a discharge mode at a first discharge power, where the first discharge power is the minimum value corresponding to the installed capacity of the energy storage system, the current load power after taking the offset, the requested discharge power of the battery management module in the energy storage system, and the current load power exceeding the demand.

4. The energy storage system control method according to claim 1, characterized in that: Determining the target working mode of the energy storage system according to the size relationship and the working period includes: When the working period is a standby period and the preset power demand is greater than the current load power, determining that the target working mode is a standby mode; When the working period is a standby period and the preset power demand is not greater than the current load power, the target working mode is determined to be a discharge mode.

5. The energy storage system control method according to claim 4, characterized in that: In the case where the working period is a standby period and the preset power demand is not greater than the current load power, after determining that the target working mode is a discharge mode, the method further includes: The energy storage system is controlled to operate in a discharge mode at a first discharge power, where the first discharge power is the minimum value corresponding to the installed capacity of the energy storage system, the current load power after taking the offset, the requested discharge power of the battery management module, and the current load power exceeding the demand.

6. The energy storage system control method according to claim 1, characterized in that: Determining the target working mode of the energy storage system according to the size relationship and the working period specifically includes: When the working period is a discharging period, determining that the target working mode of the energy storage system is a discharging mode; According to the magnitude relationship, the discharge power of the energy storage system in the discharge mode is determined.

7. The energy storage system control method according to claim 6, characterized in that: When the energy storage system operates in the backflow prevention prohibition mode, determining the discharge power of the energy storage system in the discharge mode according to the magnitude relationship specifically includes: When the preset power demand is greater than the current load power, determining the discharge power of the energy storage system in the discharge mode according to a first difference between the current discharge power and the previous discharge power; When the preset power demand is not greater than the current load power, the energy storage system is controlled to operate in a discharge mode at a second discharge power, wherein the second discharge power is a larger value among the difference between the preset power demand and the current load power and the preset discharge power of the corresponding discharge period, the current load power, and the minimum value corresponding to the requested discharge power of the battery management module; When the preset power demand is greater than the current load power, determining the discharge power of the energy storage system in the discharge mode according to a first difference between the current discharge power and the previous discharge power specifically includes: When the first difference is greater than zero and not greater than a first preset difference, determining that the current discharge power is equal to the previous discharge power; In the case where the first difference is greater than the first preset difference, the energy storage system is controlled to operate in a discharge mode at a third discharge power, where the third discharge power is the smaller of the current load power and the requested discharge power of the battery management module minus the difference between the discharge power last sent by the energy storage system and the last discharge power sent by the energy storage system multiplied by the convergence coefficient; When the first difference is less than zero, the energy storage system is controlled to operate in a discharge mode at a fourth discharge power, where the fourth discharge power is the minimum value corresponding to the current load power, the preset discharge power corresponding to the discharge period, and the requested discharge power of the battery management module.

8. The energy storage system control method according to claim 6, characterized in that: When the energy storage system operates in the anti-backflow enabling mode, determining the discharge power of the energy storage system in the discharge mode according to the magnitude relationship specifically includes: When the preset power demand is greater than the current load power after taking the offset, determining the discharge power of the energy storage system in the discharge mode according to a first difference between the current discharge power and the previous discharge power; In the case where the preset power demand is not greater than the current load power after taking the offset, the energy storage system is controlled to operate in a discharge mode at a fifth discharge power, wherein the fifth discharge power is the larger value of the difference between the preset power demand and the current load power and the preset discharge power of the corresponding discharge period, the current load power after taking the offset, and the minimum value corresponding to the requested discharge power of the battery management module; When the preset power demand is greater than the current load power after taking the offset, determining the discharge power of the energy storage system in the discharge mode according to a first difference between the current discharge power and the previous discharge power specifically includes: When the first difference is greater than zero and not greater than a first preset difference, determining that the current discharge power is equal to the previous discharge power; In the case where the first difference is greater than the first preset difference, the energy storage system is controlled to operate in a discharge mode at a sixth discharge power, wherein the sixth discharge power is a value obtained by multiplying the smaller value of the current load power after the offset and the requested discharge power of the battery management module minus the discharge power last issued by the energy storage system by a smoothing coefficient and adding the difference to the discharge power last issued by the energy storage system; When the first difference is less than zero, the energy storage system is controlled to operate in a discharge mode at a seventh discharge power, where the seventh discharge power is the minimum value corresponding to the current load power after taking the offset, the preset discharge power corresponding to the discharge period, and the requested discharge power of the battery management module.

9. A controller, characterized in that: The controller is used to implement the energy storage system control method according to any one of claims 1 to 8.

10. An energy storage system, characterized in that: The energy storage system comprises the controller as claimed in claim 9.

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