Energy storage system and energy storage control method

Abstract

The present application discloses an energy storage system and an energy storage control method. The energy storage system includes an energy storage converter, an energy storage unit, a power detection unit, and a control unit. The AC side of the energy storage converter is connected to the user's grid bus, and the DC side of the energy storage converter is connected to the energy storage unit. The energy storage converter is used to control the charging and discharging process of the energy storage unit. The power detection unit is used to obtain the total power of the user's grid bus. The control unit is connected to the power detection unit, the energy storage converter, and the energy storage unit. The control unit is used to adjust the operating power of the energy storage converter according to the total power of the user's grid bus during a preset charging period or a preset discharging period, so that the total power of the user's grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets the preset requirements. According to the energy storage system and energy storage control method of the present application, it is possible to achieve smooth fluctuations in grid power, improve energy storage efficiency and economic benefits.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and more particularly to an energy storage system and an energy storage control method. Background Art

[0002] An energy storage system is an electrical device that converts electrical energy into chemical energy or other forms of energy, stores it, and can release the electrical energy according to set requirements. It is mainly used for peak regulation, peak shaving and valley filling in power systems.

[0003] With the rapid development of new energy industries like wind power and photovoltaics, as well as the rapid pace of industrialization, the price differential between peak and valley power demand continues to widen. Factories and businesses experience significant differences in power demand between daytime and nighttime. To achieve energy conservation and emissions reduction, user-side energy storage systems can manage electricity directly at the source. Based on individual user patterns and peak and valley electricity pricing, energy storage charging and discharging times can be rationally scheduled and organized for each user. This reduces peak loads, fills valley loads, and reduces the peak-valley difference in grid load, balancing power generation and consumption and improving grid load stability.

[0004] User-side peak shaving and valley filling refers to factories and businesses storing electricity during the nighttime off-peak period in energy storage devices such as energy storage batteries, releasing the stored electricity during the daytime peak electricity price period, and providing it to the load for electricity use. This means that cheap electricity at the nighttime off-peak price is transferred to the daytime peak electricity price period. By reducing the demand for grid electricity during the daytime peak load, electricity bill savings are generated based on the peak-valley electricity price difference between daytime and nighttime.

[0005] At present, although the energy storage systems on the user side have adopted a peak-shaving and valley-filling control and profit model, most of them use a simple time logic of charging during the night valley and discharging during the day peak. The control model is relatively simple, and the utilization rate and yield rate of the energy storage system still need to be improved.

[0006] Therefore, improvements are needed to at least partially solve the above problems. Summary of the Invention

[0007] The Summary of the Invention introduces a series of simplified concepts that will be further described in the Detailed Description of the Invention. The Summary of the Invention is not intended to limit the key features and essential features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0008] In order to at least partially solve the above problems, according to a first aspect of the present invention, there is provided an energy storage system, which includes an energy storage converter, an energy storage unit, a power detection unit and a control unit;

[0009] The AC side of the energy storage converter is connected to the user grid bus, and the DC side of the energy storage converter is connected to the energy storage unit. The energy storage converter is used to control the charging and discharging process of the energy storage unit;

[0010] The power detection unit is used to obtain the total power of the user power grid bus;

[0011] The control unit is connected to the power detection unit, the energy storage converter and the energy storage unit. The control unit is used to adjust the operating power of the energy storage converter according to the total power of the user grid bus during a preset charging period or a preset discharging period, so that the total power of the user grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets the preset requirements.

[0012] Exemplarily, the user grid bus is connected to the public grid bus via a transformer;

[0013] The power detection unit includes a power meter, which is arranged on a side of the transformer connected to the public grid bus.

[0014] Exemplarily, the control unit is configured to:

[0015] Determine whether the current time is in a preset charging period or a preset discharging period;

[0016] When the current time is within the preset charging period, controlling the energy storage converter to convert the alternating current from the user grid bus into direct current to charge the energy storage unit;

[0017] When the current time is within the preset discharge period, controlling the energy storage converter to convert the direct current from the energy storage unit into alternating current and transmit it to the user grid bus;

[0018] When the current time is not within the preset charging period and the preset discharging period, the energy storage converter is controlled to stop and wait.

[0019] Exemplarily, when the current time is within the preset charging period, adjusting the operating power of the energy storage converter according to the total power of the user grid bus so that the total power of the user grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets a preset requirement includes:

[0020] Determining whether the total power of the user grid bus is greater than a first preset power and the current operating power of the energy storage converter is greater than a first preset adjustment power;

[0021] When the determination is yes, reducing the current operating power of the energy storage converter by the first preset adjustment power;

[0022] Determining whether the total power of the user grid bus is less than a second preset power and the current operating power of the energy storage converter is less than a first set operating power of the energy storage converter, wherein the first preset power is greater than the second preset power;

[0023] When the determination is yes, increasing the current operating power of the energy storage converter by the first preset adjustment power;

[0024] Determining whether the total power of the user power grid bus is greater than or equal to the second preset power and less than or equal to the first preset power;

[0025] When the determination is yes, maintaining the current operating power of the energy storage converter unchanged;

[0026] Determining whether the remaining power of the energy storage unit is greater than or equal to a preset upper limit power;

[0027] Repeating the above steps at least once at a first preset time interval until the remaining power of the energy storage unit is greater than or equal to the preset upper limit power;

[0028] When the remaining power of the energy storage unit is greater than or equal to the preset upper limit power, the energy storage converter is controlled to stop and wait.

[0029] Exemplarily, at least one load is connected to the user power grid bus;

[0030] The first preset regulated power is 110%-120% of the average fluctuation range of the total power of the load;

[0031] The first preset time interval is 5-20 seconds;

[0032] The difference between the first preset power and the second preset power is greater than or equal to the first preset adjustment power;

[0033] The first set operating power is the rated operating power of the energy storage converter.

[0034] Exemplarily, the control unit is further configured to:

[0035] When the current time is within the preset charging period and the total power of the user grid bus is greater than or equal to a third preset power, the energy storage converter is controlled to shut down and wait, wherein the third preset power is greater than the first preset power.

[0036] Exemplarily, when the current time is within the preset discharge period, adjusting the operating power of the energy storage converter according to the total power of the user grid bus so that the total power of the user grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets the preset requirement includes:

[0037] Determining whether the total power of the user grid bus is greater than a fourth preset power and the current operating power of the energy storage converter is less than a second set operating power of the energy storage converter;

[0038] When the determination is yes, increasing the current operating power of the energy storage converter by a second preset adjustment power;

[0039] Determining whether the total power of the user grid bus is less than a fifth preset power and the current operating power of the energy storage converter is greater than the second preset adjustment power, wherein the fourth preset power is greater than the fifth preset power;

[0040] When the determination is yes, reducing the current operating power of the energy storage converter by the second preset adjustment power;

[0041] Determining whether the total power of the user power grid bus is greater than or equal to the fifth preset power and less than or equal to the fourth preset power;

[0042] When the determination is yes, maintaining the current operating power of the energy storage converter unchanged;

[0043] Determining whether the remaining power of the energy storage unit is less than a preset lower limit power;

[0044] Repeating the above steps at least once at a second preset time interval until the remaining power of the energy storage unit is less than the preset lower limit power;

[0045] When the remaining power of the energy storage unit is less than the preset lower limit power, the energy storage converter is controlled to stop and wait.

[0046] Exemplarily, at least one load is connected to the user power grid bus;

[0047] The second preset regulated power is 110%-120% of the average fluctuation range of the total power of the load;

[0048] The second preset time interval is 5-20 seconds;

[0049] The difference between the fourth preset power and the fifth preset power is greater than or equal to the second preset adjustment power;

[0050] The second set operating power is the rated operating power of the energy storage converter.

[0051] Exemplarily, the control unit is further configured to:

[0052] When the current time is in the preset discharge period and the total power of the user grid bus is less than or equal to a sixth preset power, the energy storage converter is controlled to shut down and wait, wherein the sixth preset power is less than the fifth preset power.

[0053] Exemplarily, the energy storage unit includes a battery management system and a battery pack; or,

[0054] The energy storage unit includes a supercapacitor array.

[0055] According to a second aspect of the present invention, there is provided an energy storage control method, comprising:

[0056] Determine whether the current time belongs to a preset charging period or a preset discharging period;

[0057] When the current time belongs to the preset charging period or the preset discharging period, obtaining the total power of the user grid bus, wherein the user grid bus is connected to the AC side of the energy storage converter, and the DC side of the energy storage converter is connected to the energy storage unit;

[0058] The operating power of the energy storage converter is adjusted according to the total power of the user grid bus, so that the total power of the user grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets the preset requirements.

[0059] Exemplarily, when the current time falls within the preset charging period, adjusting the operating power of the energy storage converter according to the total power of the user grid bus so that the total power of the user grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets the preset requirement includes:

[0060] Determining whether the total power of the user grid bus is greater than a first preset power and the current operating power of the energy storage converter is greater than a first preset adjustment power;

[0061] When the determination is yes, reducing the current operating power of the energy storage converter by the first preset adjustment power;

[0062] Determining whether the total power of the user grid bus is less than a second preset power and the current operating power of the energy storage converter is less than a first set operating power of the energy storage converter, wherein the first preset power is greater than the second preset power;

[0063] When the determination is yes, increasing the current operating power of the energy storage converter by the first preset adjustment power;

[0064] Determining whether the total power of the user power grid bus is greater than or equal to the second preset power and less than or equal to the first preset power;

[0065] When the determination is yes, maintaining the current operating power of the energy storage converter unchanged;

[0066] Determining whether the remaining power of the energy storage unit is greater than or equal to a preset upper limit power;

[0067] Repeating the above steps at least once at a first preset time interval until the remaining power of the energy storage unit is greater than or equal to the preset upper limit power;

[0068] When the remaining power of the energy storage unit is greater than or equal to the preset upper limit power, the energy storage converter is controlled to stop and wait.

[0069] Exemplarily, at least one load is connected to the user power grid bus;

[0070] The first preset regulated power is 110%-120% of the average fluctuation range of the total power of the load;

[0071] The first preset time interval is 5-20 seconds;

[0072] The difference between the first preset power and the second preset power is greater than or equal to the first preset adjustment power;

[0073] The first set operating power is the rated operating power of the energy storage converter.

[0074] Exemplarily, the energy storage control method further includes:

[0075] When the current time is within the preset charging period, determining whether the total power of the user power grid bus is greater than or equal to a third preset power, wherein the third preset power is greater than the first preset power;

[0076] When the total power of the user grid bus is greater than or equal to the third preset power, controlling the energy storage converter to stop and wait;

[0077] When the total power of the user grid bus is less than the third preset power, the operating power of the energy storage converter is adjusted according to the total power of the user grid bus, so that the total power of the user grid bus is stabilized within the preset power range until the remaining power of the energy storage unit meets the preset requirements.

[0078] Exemplarily, when the current time is within the preset discharge period, adjusting the operating power of the energy storage converter according to the total power of the user grid bus so that the total power of the user grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets a preset requirement includes:

[0079] Determining whether the total power of the user grid bus is greater than a fourth preset power and the current operating power of the energy storage converter is less than a second set operating power of the energy storage converter;

[0080] When the determination is yes, increasing the current operating power of the energy storage converter by a second preset adjustment power;

[0081] Determining whether the total power of the user grid bus is less than a fifth preset power and the current operating power of the energy storage converter is greater than the second preset adjustment power, wherein the fourth preset power is greater than the fifth preset power;

[0082] When the determination is yes, reducing the current operating power of the energy storage converter by the second preset adjustment power;

[0083] Determining whether the total power of the user power grid bus is greater than or equal to the fifth preset power and less than or equal to the fourth preset power;

[0084] When the determination is yes, maintaining the current operating power of the energy storage converter unchanged;

[0085] Determining whether the remaining power of the energy storage unit is less than a preset lower limit power;

[0086] Repeating the above steps at least once at a second preset time interval until the remaining power of the energy storage unit is less than the preset lower limit power;

[0087] When the remaining power of the energy storage unit is less than the preset lower limit power, the energy storage converter is controlled to stop and wait.

[0088] Exemplarily, at least one load is connected to the user power grid bus;

[0089] The second preset regulated power is 110%-120% of the average fluctuation range of the total power of the load;

[0090] The second preset time interval is 5-20 seconds;

[0091] The difference between the fourth preset power and the fifth preset power is greater than or equal to the second preset adjustment power;

[0092] The second set operating power is the rated operating power of the energy storage converter.

[0093] Exemplarily, the energy storage control method further includes:

[0094] When the current time is in the preset discharge period, determining whether the total power of the user grid bus is less than or equal to a sixth preset power, wherein the sixth preset power is less than the fifth preset power;

[0095] When the total power of the user grid bus is less than or equal to the sixth preset power, controlling the energy storage converter to stop and wait;

[0096] When the total power of the user grid bus is greater than the sixth preset power, the operating power of the energy storage inverter is adjusted according to the total power of the user grid bus, so that the total power of the user grid bus is stabilized within the preset power range until the remaining power of the energy storage unit meets the preset requirements.

[0097] According to the energy storage system and energy storage control method of the present invention, by adjusting the operating power of the energy storage converter according to the total power of the user grid bus during a preset charging period or a preset discharging period, the operating power of the energy storage converter can be automatically and synchronously adjusted with the fluctuation of the load power. While achieving the smooth regulation of grid power fluctuations, the utilization rate and profitability of the energy storage system can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] The following drawings of this application are hereby incorporated as part of this application for understanding this application. The drawings show the embodiments of this application and their descriptions, and are used to explain the device and principle of this application. In the drawings,

[0099] Figure 1 A schematic structural diagram of an energy storage system according to an embodiment of the present invention;

[0100] Figure 2 A schematic diagram of a real-time charging power curve of an energy storage system during a preset charging period according to an embodiment of the present invention;

[0101] Figure 3 2 is a schematic diagram of a real-time discharge power curve of an energy storage system during a preset discharge period according to an embodiment of the present invention.

[0102] Figure 4 A schematic flow chart of an energy storage control method according to an embodiment of the present invention;

[0103] Figure 5 FIG. 4 is a flow chart of an energy storage control method according to an embodiment of the present invention.

[0104] Description of reference numerals:

[0105] 1-Energy storage converter, 2-Energy storage unit, 3-Power detection unit, 4-Control unit, 5-User grid bus, 6-Transformer, 7-Load, 8-Transformer, 9-Public grid bus;

[0106] 10-total power of the user's grid bus, 11-power of the energy storage system, 12-total power of the load;

[0107] 20-Total power of the load, 21-Power of the energy storage system, 22-Total power of the user's grid bus. DETAILED DESCRIPTION

[0108] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it will be apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, some technical features well known in the art are not described in order to avoid confusion with the present application.

[0109] It should be understood that the present application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the disclosure thorough and complete and to fully convey the scope of the present application to those skilled in the art. In the drawings, the dimensions and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals throughout represent like elements.

[0110] It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Therefore, without departing from the teachings of this application, the first element, component, region, layer, or part discussed below may be represented as a second element, component, region, layer, or part.

[0111] The purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present application. When used herein, the singular forms "a", "an", and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0112] Refer to the attached Figure 1 An energy storage system according to an embodiment of the present invention is exemplarily described.

[0113] The energy storage system includes an energy storage converter 1 , an energy storage unit 2 , a power detection unit 3 and a control unit 4 .

[0114] The energy storage converter 1, also known as a bidirectional energy storage inverter or PCS (Power Conversion System), has its AC side connected to the user grid bus 5 and its DC side connected to the energy storage unit 2. It is a device that performs bidirectional conversion of electrical energy. It is used to invert the DC power from the energy storage unit 2 into AC power for transmission to the user grid bus 5. It is also used to rectify the AC power from the user grid bus 5 into DC power to charge the energy storage unit 2. In other words, the energy storage converter 1 is used to control the charging and discharging processes of the energy storage unit 2. The user grid bus 5 is connected not only to the energy storage inverter but also to at least one load 7 (i.e., user-side electrical equipment). The AC side of the energy storage converter 1 can be connected to the user grid bus 5 via a transformer 6. The user grid bus 5 is connected to the public grid bus 9 via a transformer 8. The public grid bus 9 is also known as the power supply grid bus and is used to supply power to the user grid bus 5.

[0115] In this embodiment, the energy storage unit 2 includes a battery management system (BMS) and a battery pack. In other embodiments, the energy storage unit 2 may include a supercapacitor array. In other embodiments, the energy storage unit 2 may also include other suitable energy storage devices, as long as they can stably and controllably store and release DC power.

[0116] The power detection unit 3 is used to obtain the total power of the user grid bus 5. During the charging process, the total power of the user grid bus 5 is equal to the sum of the total power of the load 7 and the power of the energy storage system. During the discharging process, the total power of the user grid bus 5 is equal to the total power of the load 7 minus the power of the energy storage system. In some embodiments, the power of the energy storage system may specifically refer to the operating power of the energy storage converter 1. In this embodiment, the power detection unit 3 includes a power meter, which is arranged on the side where the transformer is connected to the public grid bus 9 to detect the real-time power there, which is the total power of the user grid bus 5. In some other embodiments, the power detection unit 3 may also include a power meter arranged on the user grid bus 5, which is used to obtain the total power of the user grid bus 5. In some other embodiments, the power detection unit 3 may also include a voltage sensor and a current sensor arranged on the user grid bus 5, which are used to obtain the total power of the user grid bus 5.

[0117] The control unit 4 is connected to the power detection unit 3, the energy storage converter 1 and the energy storage unit 2. Thus, the control unit 4 can obtain the total power of the user grid bus 5 in real time based on the detection result of the power detection unit 3; the control unit 4 can obtain and adjust the operating power of the energy storage converter 1, and control the start and shutdown waiting of the energy storage converter 1; the control unit 4 can obtain the remaining power (State of Charge, SOC) of the energy storage unit 2. In some embodiments, the control unit 4 can be an energy management system (Energy Management System, EMS). In some embodiments, the control unit 4 can include a single-chip microcomputer or other control device with computing processing capabilities. The control unit 4 is used to adjust the operating power of the energy storage converter 1 according to the total power of the user grid bus 5 during a preset charging period or a preset discharging period, so that the total power of the user grid bus 5 is stabilized within a preset power range until the remaining power of the energy storage unit meets the preset requirements.

[0118] Specifically, control unit 4 determines whether the current time is within a preset charging period or a preset discharging period, where the preset charging period and the preset discharging period can be determined based on the period during which peak and valley electricity prices fall. When the current time is within the preset charging period (when the electricity price may be at a low valley price), control unit 4 controls energy storage converter 1 to convert AC power from user grid bus 5 into DC power to charge energy storage unit 2. When the current time is within the preset discharging period (when the electricity price may be at a peak price), control unit 4 controls energy storage converter 1 to convert DC power from energy storage unit 2 into AC power and transmit it to user grid bus 5. When the current time is not within the preset charging period or the preset discharging period, control unit 4 controls energy storage converter 1 to shut down and wait. By storing electrical energy in energy storage unit 2 during valley electricity price periods and then releasing the stored energy during peak electricity price periods to supply load 7 for use, this allows cheaper electricity at valley electricity prices at night to be transferred to use during peak electricity prices during the day. By reducing the demand for grid electricity during peak electricity price periods, electricity cost savings are generated based on the difference in peak and valley electricity prices between daytime and nighttime.

[0119] When the current time is in the preset charging period, the operating power of the energy storage converter 1 is adjusted according to the total power of the user grid bus 5, so that the total power of the user grid bus 5 is stabilized within the preset power range until the remaining power of the energy storage unit 2 meets the preset requirements, including the following steps:

[0120] Determine whether the total power of the user's grid bus 5 is greater than a first preset power and the current operating power of the energy storage converter 1 is greater than a first preset adjustment power. Specifically, the first preset power is the upper limit of the power consumption. When the total power of the user's grid bus 5 exceeds the first preset power, it indicates that the total power of the user's grid bus 5 is too large and needs to be reduced. The first preset adjustment power is the value that is increased or decreased each time the current operating power of the energy storage converter 1 is adjusted during the charging process. It is determined by the capacity of the transformer 8 and the average fluctuation range of the total power of the load 7. The first preset adjustment power can be 5%-20% of the capacity of the transformer 8, or 110%-120% of the average fluctuation range of the total power of the load 7. The average fluctuation range of the total power of the load 7 can be determined by statistically analyzing the historical fluctuations of the total power of the load 7 (especially the historical fluctuations of the total power of the load 7 during the preset charging period). In some embodiments, the average fluctuation range can be the average fluctuation range of the total power of the load 7 during the preset charging period. For example, if the average fluctuation range of the total power of the load 7 during the preset charging period is 100kW, the first preset adjustment power can be 110-120kW. The average fluctuation amplitude of the total power of load 7 during the preset charging period can be determined in the following manner: the preset charging period is divided into multiple time intervals (the duration of each time interval is the time interval) at a preset time interval (for example, 5-20 seconds or other suitable time intervals), and the fluctuation amplitude of the total power of load 7 in each time interval within the preset charging period is determined based on the historical fluctuation of the total power of load 7 during the preset charging period (that is, the difference between the maximum and minimum values ​​of the total power of load 7 in each time interval), and then the average value of the fluctuation amplitude of each time interval is calculated, which is the average fluctuation amplitude of the total power of load 7 during the preset charging period.

[0121] If the determination is yes, that is, when the total power of the user grid bus 5 is greater than the first preset power and the current operating power of the energy storage converter 1 is greater than the first preset regulated power, the current operating power of the energy storage converter 1 is reduced by the first preset regulated power. That is, the current operating power of the energy storage converter 1 is reduced by the first preset regulated power and used as the new operating power. Specifically, when the total power of the user grid bus 5 is greater than the first preset power, reducing the operating power of the energy storage converter 1 can also reduce the total power of the user grid bus 5. Adjusting the current operating power when it is greater than the first preset regulated power can avoid shutting down the energy storage converter 1. In some embodiments, the current operating power of the energy storage converter 1 can also be reduced by the first preset regulated power when the total power of the user grid bus 5 is greater than the first preset power, regardless of whether the current operating power is greater than the first preset regulated power. If the current operating power after being reduced by the first preset regulated power is less than or equal to 0, the energy storage converter 1 is controlled to shut down and wait or operate at a preset minimum operating power.

[0122] Determine whether the total power of the user grid bus 5 is less than the second preset power and the current operating power of the energy storage converter 1 is less than the first set operating power of the energy storage converter 1, wherein the first preset power is greater than the second preset power. Specifically, when the total power of the user grid bus 5 is lower than the first preset power, it means that the total power of the user grid bus 5 is small and can be increased. The difference between the first preset power and the second preset power can be greater than or equal to the first preset adjustment power. The first set operating power can be the rated operating power of the energy storage converter 1 when charging.

[0123] When the judgment is yes, that is, the total power of the user grid bus 5 is less than the second preset power and the current operating power of the energy storage converter 1 is less than the first set operating power of the energy storage converter 1, the current operating power of the energy storage converter 1 is increased by the first preset adjustment power, that is, the current operating power of the energy storage converter 1 is increased by the first preset adjustment power as the new operating power. Specifically, when the total power of the user grid bus 5 is less than the second preset power, increasing the operating power of the energy storage converter 1 can increase the total power of the user grid bus 5. In some embodiments, when the current operating power of the energy storage converter 1 exceeds the first set operating power after increasing the first preset adjustment power, the energy storage converter 1 is controlled to adjust the current operating power to the first set operating power.

[0124] It is determined whether the total power of the user grid bus 5 is greater than or equal to the second preset power and less than or equal to the first preset power.

[0125] When the determination is yes, that is, the total power of the user grid bus 5 is greater than or equal to the second preset power and less than or equal to the first preset power, the current operating power of the energy storage converter 1 is kept unchanged.

[0126] Determine whether the remaining power of the energy storage unit 2 is greater than or equal to a preset upper limit power. Specifically, the preset upper limit power can be the power when the energy storage unit 2 is fully charged. If the remaining power of the energy storage unit 2 exceeds the preset upper limit power, overcharging may occur.

[0127] The above steps are cyclically performed at least once at a first preset time interval until the remaining power of the energy storage unit 2 is greater than or equal to the preset upper limit power. Specifically, the first preset time interval determines the frequency of adjusting the operating power of the energy storage inverter following the fluctuation of the total power of the user grid bus 5. The value of the first preset time interval can be determined by the fluctuation frequency of the adjustment power curve, which can generally be set to 5-20s. In some embodiments, it can also be 1-5 seconds or less. In some embodiments, the time interval for dividing the preset charging period into multiple time intervals can be the same as the first preset time interval. Since the above steps are cyclically performed at the first preset time interval, when the total power of the user grid bus 5 is greater than the first preset power or less than the second preset power, the control unit 4 will correspondingly reduce or increase the current operating power of the energy storage inverter 1, and ultimately stabilize the total power of the user grid bus 5 within a range greater than or equal to the second preset power and less than or equal to the first preset power, thereby achieving a smooth fluctuation of the total power of the user grid bus 5. Even if the total power of the user grid bus 5 changes due to a change in the power of the load 7, the above steps can promptly adjust the total power of the user grid bus 5 to a range greater than or equal to the second preset power and less than or equal to the first preset power. Since the first preset adjustment power can be set to 110%-120% of the average fluctuation range of the total power of the load 7 during the preset charging period, when the total power of the load 7 fluctuates, causing the total power of the user grid bus 5 to exceed the range greater than or equal to the second preset power and less than or equal to the first preset power, by increasing or decreasing the current operating power of the energy storage converter 1 by the first preset adjustment power, the fluctuation in the total power of the load 7 can be offset in a very short time, and the total power of the user grid bus 5 can be returned to the above range.

[0128] When the remaining power of the energy storage unit 2 is greater than or equal to the preset upper limit power, the energy storage converter 1 is controlled to stop and wait. That is, when the energy storage unit 2 is fully charged, the energy storage converter 1 is controlled to stop and wait, and no longer charges the energy storage unit 2 to avoid overcharging.

[0129] It should be noted that, for the above-mentioned remaining power of the energy storage unit 2 meeting the preset requirements, it does not mean that the remaining power of the energy storage unit 2 must be greater than or equal to the preset upper limit power during the preset charging period. Instead, it should be understood that during the preset charging period, if the remaining power of the energy storage unit 2 is greater than or equal to the preset upper limit power, the energy storage system stops the charging process (controls the energy storage converter 1 to stop and wait), otherwise, the above steps are cyclically executed at the first preset time interval; if at the end of the preset charging period, the remaining power of the energy storage unit 2 is not greater than or equal to the preset upper limit power, the energy storage system also stops the charging process (controls the energy storage converter 1 to stop and wait).

[0130] Furthermore, the control unit 4 is further configured to: when the current time is within the preset charging period and the total power of the user grid bus 5 is greater than or equal to a third preset power, control the energy storage converter 1 to shut down and wait. The third preset power is the protection power of the transformer 8, i.e., the upper limit of the shutdown point, and the third preset power is greater than the first preset power. In other words, when the total power of the user grid bus 5 is excessive, the energy storage converter 1 is controlled to shut down and wait to avoid transformer overload damage and ensure safe and stable operation of the transformer 8.

[0131] See attached Figure 2 , which shows a schematic diagram of the real-time charging power curve of the energy storage system during a preset charging period in one embodiment of the present application, wherein the total power 10 of the user's grid bus 5 is equal to the sum of the power 11 of the energy storage system and the power 12 of the load 7. When the total power 12 of the load 7 fluctuates, the power 11 of the energy storage system will be adjusted accordingly to reduce or increase the fluctuation, ensuring that the total power 10 of the user's grid bus 5 fluctuates smoothly. In some embodiments, the power 11 of the energy storage system can specifically refer to the operating power of the energy storage converter 1.

[0132] When the current time is within the preset discharge period, the operating power of the energy storage converter 1 is adjusted according to the total power of the grid bus, so that the total power of the user grid bus 5 is stabilized within the preset power range until the remaining power of the energy storage unit 2 meets the preset requirements, including the following steps:

[0133] Determine whether the total power of the user grid bus 5 is greater than a fourth preset power and the current operating power of the energy storage converter 1 is less than the second set operating power of the energy storage converter 1. Specifically, when the total power of the user grid bus 5 exceeds the fourth preset power, it indicates that the total power of the user grid bus 5 is too high and needs to be reduced. The second set operating power may be the rated operating power of the energy storage converter 1 during discharge, which may be the same as or different from the first set operating power.

[0134] When the determination is yes, that is, the total power of the user grid bus 5 is greater than the fourth preset power and the current operating power of the energy storage converter 1 is less than the second set operating power of the energy storage converter 1, the current operating power of the energy storage converter 1 is increased by the second preset regulated power. That is, the current operating power of the energy storage converter 1 is increased by the second preset regulated power as the new operating power. Specifically, the second preset regulated power is the value that is increased or decreased each time the current operating power of the energy storage converter 1 is adjusted during the discharge process. It is determined by the capacity of the transformer 8 and the average fluctuation range of the total power of the load 7. The second preset regulated power can be 5%-20% of the capacity of the transformer 8 or 110%-120% of the average fluctuation range of the total power of the load 7. The average fluctuation range of the total power of the load 7 can be determined by statistically analyzing the historical fluctuations of the load 7 (especially the historical fluctuations of the load 7 during the preset discharge period). In some embodiments, the average fluctuation amplitude may be the average fluctuation amplitude of the total power of the load 7 during the preset discharge period. For example, when the average fluctuation amplitude of the total power of the load 7 during the preset discharge period is 100 kW, the second preset adjustment power may be 110-120 kW. The average fluctuation amplitude of the total power of the load 7 during the preset discharge period may be determined as follows: the preset discharge period is divided into a plurality of time intervals (the duration of each time interval being the time interval) at a preset time interval (e.g., 5-20 seconds or other suitable time intervals), and the fluctuation amplitude of the total power of the load 7 during each time interval during the preset charging period is determined based on the historical fluctuation of the total power of the load 7 during the preset discharge period (i.e., the difference between the maximum and minimum values ​​of the total power of the load 7 during each time interval). The average value of the fluctuation amplitudes of each time interval is then calculated. This average value is the average fluctuation amplitude of the total power of the load 7 during the preset charging period. When the total power of the user grid bus 5 is greater than the fourth preset power, increasing the operating power of the energy storage converter 1 can enable the energy storage converter 1 to supply more electric energy to the load 7, thereby reducing the electric energy obtained by the load 7 from the public grid bus 9, and thus reducing the total power of the user grid bus 5. The second preset adjustment power and the first preset adjustment power can be the same or different. In some embodiments, when the current operating power of the energy storage converter 1 increases by the second preset adjustment power and exceeds the second set operating power, the energy storage converter 1 is controlled to adjust the current operating power to the second set operating power.

[0135] Determine whether the total power of the user grid bus 5 is less than the fifth preset power and the current operating power of the energy storage converter 1 is greater than the second preset regulated power, where the fourth preset power is greater than the fifth preset power. Specifically, the fifth preset power is the lower limit power. When the total power of the user grid bus 5 is less than the fifth preset power, it indicates that the total power of the user grid bus 5 is low and needs to be increased.

[0136] If the determination is yes, that is, when the total power of the user grid bus 5 is less than the fifth preset power and the current operating power of the energy storage converter 1 is greater than the second preset regulated power, the current operating power of the energy storage converter 1 is reduced by the second preset regulated power. Specifically, when the total power of the user grid bus 5 is less than the fifth preset power, the operating power of the energy storage converter 1 is reduced, reducing the power supplied by the energy storage converter 1 to the load 7, thereby increasing the power drawn by the load 7 from the public grid bus 9 and increasing the total power of the user grid bus 5. Adjusting the current operating power when it is greater than the second preset regulated power can avoid shutting down the energy storage converter 1. In some embodiments, the current operating power of the energy storage converter 1 can also be reduced by the second preset regulated power when the total power of the user grid bus 5 is greater than the fifth preset power, regardless of whether the current operating power is greater than the second preset regulated power. If the current operating power is less than or equal to zero after being reduced by the second preset regulated power, the energy storage converter 1 is controlled to shut down and wait or operate at the preset minimum operating power.

[0137] It is determined whether the total power of the user grid bus 5 is greater than or equal to the fifth preset power and less than or equal to the fourth preset power.

[0138] When the determination is yes, that is, the total power of the user grid bus 5 is greater than or equal to the fifth preset power and less than or equal to the fourth preset power, the current operating power of the energy storage converter 1 is kept unchanged.

[0139] Determine whether the remaining power of the energy storage unit 2 is less than a preset lower limit. Specifically, the preset lower limit can be the power when the energy storage unit 2 is normally fully discharged. If the remaining power of the energy storage unit 2 is lower than the preset lower limit, overdischarge may occur.

[0140] The above steps are cyclically performed at least once at a second preset time interval until the remaining power of the energy storage unit 2 is less than the preset lower limit power. Specifically, the second preset time interval determines the frequency of adjusting the operating power of the energy storage inverter to follow the fluctuation of the total power of the user grid bus 5. The second preset time interval can be determined by the fluctuation frequency of the adjustment power curve, which can generally be set to 5-20s. In some embodiments, it can also be 1-5 seconds or less. The second preset time interval can be the same as or different from the first preset time interval. In some embodiments, the time interval for dividing the preset discharge period into multiple time intervals can be the same as the second preset time interval. Since the above steps are cyclically performed at the second preset time interval, when the total power of the user grid bus 5 is greater than the fourth preset power or less than the fifth preset power, the control unit 4 will increase or decrease the current operating power of the energy storage inverter 1 accordingly, and ultimately stabilize the total power of the user grid bus 5 within a range greater than or equal to the fifth preset power and less than or equal to the fourth preset power, thereby achieving a smooth fluctuation of the total power of the user grid bus 5. Even if the total power of the user grid bus 5 changes due to a change in the power of the load 7, the above steps can timely adjust the total power of the user grid bus 5 to a range greater than or equal to the fifth preset power and less than or equal to the fourth preset power. Since the second preset adjustment power can be set to 110%-120% of the average fluctuation amplitude of the total power of the load 7 during the preset discharge period, when the total power of the load 7 fluctuates, causing the total power of the user grid bus 5 to exceed the range greater than or equal to the fifth preset power and less than or equal to the fourth preset power, by increasing or decreasing the current operating power of the energy storage converter 1 by the second preset adjustment power, the fluctuation of the total power of the load 7 can be offset in a very short time, so that the total power of the user grid bus 5 returns to the above range. The solution of the present application can effectively ensure that when the energy storage system is discharged, the electric energy can be effectively supplied to the load 7 without flowing back into the public grid and causing an impact on it, thereby effectively improving the efficiency and profitability of the energy storage system.

[0141] When the remaining power of the energy storage unit 2 is less than the preset lower limit, the energy storage converter 1 is controlled to stop and wait. That is, when the energy storage unit 2 is fully discharged, the energy storage converter 1 is controlled to stop and wait, and no longer discharges the energy storage unit 2 to avoid over-discharge.

[0142] Furthermore, control unit 4 is further configured to control energy storage converter 1 to shut down and wait when the current time is within a preset discharge period and the total power of user grid bus 5 is less than or equal to a sixth preset power. The sixth preset power is the protection power of transformer 8 and is less than the fifth preset power. In other words, when the total power of user grid bus 5 is too low, energy storage converter 1 is controlled to shut down and wait to ensure safe and stable operation of transformer 8.

[0143] See attached Figure 3 , which shows a schematic diagram of the real-time discharge power curve of the energy storage system during a preset discharge period according to one embodiment of the present application. In this diagram, the total power 22 of the user's grid bus 5 = the total power 20 of the load 7 - the power 21 of the energy storage system. When the total power 20 of the load 7 fluctuates, the power 21 of the energy storage system increases or decreases accordingly, ensuring that the total power 22 of the user's grid bus 5 fluctuates smoothly. In some embodiments, the power 21 of the energy storage system may specifically refer to the operating power of the energy storage converter 1.

[0144] It should be noted that, for the above-mentioned remaining power of the energy storage unit 2 meeting the preset requirements, it does not mean that the remaining power of the energy storage unit 2 must be less than the preset lower limit power during the preset discharge period. Instead, it should be understood as: during the preset discharge period, if the remaining power of the energy storage unit 2 is less than the preset lower limit power, the energy storage system stops the discharge process (controls the energy storage converter 1 to stop and wait), otherwise, the above steps are cyclically executed at the first preset time interval; if at the end of the preset charging period, the remaining power of the energy storage unit 2 is not less than the preset lower limit power, the energy storage system also stops the charging process (controls the energy storage converter 1 to stop and wait).

[0145] Refer to the attached Figure 2 The energy storage control method according to one embodiment of the present invention is exemplified. The energy storage control method may be based on the energy storage system described above, and the energy storage control method includes the following steps:

[0146] S100: Determine whether the current time belongs to a preset charging period or a preset discharging period.

[0147] Specifically, the control unit 4 determines whether the current time is in a preset charging period or a preset discharging period, where the preset charging period and the preset discharging period can be determined according to the period of the peak and valley electricity price. When the current time is in the preset charging period (the electricity price can be the valley electricity price at this time), the control unit 4 controls the energy storage converter 1 to convert the AC power from the user grid bus 5 into DC power to charge the energy storage unit 2. When the current time is in the preset discharging period (the electricity price can be the peak electricity price at this time), the control unit 4 controls the energy storage converter 1 to convert the DC power from the energy storage unit 2 into AC power and transmit it to the user grid bus 5. When the current time is not in the preset charging period or the preset discharging period, the energy storage converter 1 is controlled to shut down and wait.

[0148] S200: When the current time belongs to a preset charging period or a preset discharging period, the total power of the user power grid bus 5 is obtained.

[0149] Specifically, the total power of the user grid bus 5 can be detected by a power meter provided on the side where the transformer is connected to the public grid bus 9. In some other embodiments, the total power of the user grid bus 5 can also be obtained by a power meter provided on the user grid bus 5. In some other embodiments, the voltage and current of the user grid bus 5 can also be obtained by a voltage sensor and a current sensor provided on the user grid bus 5, and then the total power of the user grid bus 5 is calculated by the voltage and current. In the preset charging period, the total power of the user grid bus 5 = the total power of the load 7 + the power of the energy storage system, and in the preset discharging period, the total power of the user grid bus 5 = the total power of the load 7 - the power of the energy storage system. In some embodiments, the power of the energy storage system may specifically refer to the operating power of the energy storage converter 1.

[0150] S300: Adjust the operating power of the energy storage converter 1 according to the total power of the user grid bus 5, so that the total power of the user grid bus 5 is stabilized within a preset power range until the remaining power of the energy storage unit 2 meets the preset requirements.

[0151] Regarding step S300, when the current time is within the preset charging period, the operating power of the energy storage converter 1 is adjusted according to the total power of the user grid bus 5 so that the total power of the user grid bus 5 is stabilized within a preset power range until the remaining power of the energy storage unit 2 meets the preset requirement, including the following steps:

[0152] S310: Determine whether the total power of the user grid bus 5 is greater than a first preset power and whether the current operating power of the energy storage converter 1 is greater than a first preset adjustment power.

[0153] S311: When the judgment is yes, that is, the total power of the user grid bus 5 is greater than the first preset power and the current operating power of the energy storage converter 1 is greater than the first preset adjustment power, the current operating power of the energy storage converter 1 is reduced by the first preset adjustment power, that is, the current operating power of the energy storage converter 1 is reduced by the first preset adjustment power as the new operating power.

[0154] S312: Determine whether the total power of the user grid bus 5 is less than the second preset power and the current operating power of the energy storage converter 1 is less than the first set operating power of the energy storage converter 1, wherein the first preset power is greater than the second preset power.

[0155] S313: When the judgment is yes, that is, the total power of the user grid bus 5 is less than the second preset power and the current operating power of the energy storage converter 1 is less than the first set operating power of the energy storage converter 1, the current operating power of the energy storage converter 1 is increased by the first preset adjustment power, that is, the current operating power of the energy storage converter 1 is increased by the first preset adjustment power as the new operating power.

[0156] S314: Determine whether the total power of the user grid bus 5 is greater than or equal to the second preset power and less than or equal to the first preset power.

[0157] S315: When the determination is yes, that is, when the total power of the user grid bus 5 is greater than or equal to the second preset power and less than or equal to the first preset power, the current operating power of the energy storage converter 1 is kept unchanged.

[0158] S316: Determine whether the remaining power of the energy storage unit 2 is greater than or equal to a preset upper limit power.

[0159] S317: cyclically executing the above steps at least once at a first preset time interval until the remaining power of the energy storage unit 2 is greater than or equal to the preset upper limit power.

[0160] S318: When the remaining power of the energy storage unit 2 is greater than or equal to the preset upper limit power, the energy storage converter 1 is controlled to stop and wait. That is, when the energy storage unit 2 is fully charged, the energy storage converter 1 is controlled to stop and wait, and no longer charges the energy storage unit 2 to avoid overcharging.

[0161] The specific contents of step S310 to step S318 have been described in detail above and will not be repeated here. It should be noted that, for step S317, in some embodiments, steps S310 to S316 can be cyclically executed at a first preset time interval, and steps S100 and S200 are performed in real time, and the time intervals for their execution are different from the first preset time interval. For step S317, in some embodiments, steps S100 to S200 and steps S310 to S316 can be cyclically executed at a first preset time interval. It should also be noted that the order of steps S310 to S316 is not absolute, and those skilled in the art can adjust it as needed. Steps S310, S312, and S315 can be performed sequentially or simultaneously.

[0162] Furthermore, before step S300, the energy storage control method further includes:

[0163] S400: When the current time is in the preset charging period, determine whether the total power of the user power grid bus 5 is greater than or equal to a third preset power.

[0164] S410: When the total power of the user grid bus 5 is greater than or equal to a third preset power, control the energy storage converter 1 to stop and wait;

[0165] S420: When the total power of the user grid bus 5 is less than the third preset power, the operating power of the energy storage converter 1 is adjusted according to the total power of the user grid bus 5, so that the total power of the user grid bus 5 is stabilized within the preset power range until the remaining power of the energy storage unit 2 meets the preset requirements.

[0166] The third preset power is the protection power of transformer 8, and the third preset power is greater than the first preset power. In other words, when the total power of the user grid bus 5 is too high, the energy storage converter 1 is controlled to shut down and wait to avoid transformer overload damage and ensure safe and stable operation of transformer 8.

[0167] Regarding step S300, when the current time is within the preset discharge period, the operating power of the energy storage converter 1 is adjusted according to the total power of the grid bus, so that the total power of the user grid bus 5 is stabilized within the preset power range until the remaining power of the energy storage unit 2 meets the preset requirement, including:

[0168] S320 : Determine whether the total power of the user grid bus 5 is greater than a fourth preset power and the current operating power of the energy storage converter 1 is less than a second set operating power of the energy storage converter 1 .

[0169] S321: When the judgment is yes, that is, the total power of the user grid bus 5 is greater than the fourth preset power and the current operating power of the energy storage converter 1 is less than the second set operating power of the energy storage converter 1, the current operating power of the energy storage converter 1 is increased by the second preset adjustment power, that is, the current operating power of the energy storage converter 1 is increased by the second preset adjustment power as the new operating power.

[0170] S322: Determine whether the total power of the user grid bus 5 is less than the fifth preset power and the current operating power of the energy storage converter 1 is greater than the second preset adjustment power, wherein the fourth preset power is greater than the fifth preset power.

[0171] S323: When the judgment is yes, that is, the total power of the user grid bus 5 is less than the fifth preset power and the current operating power of the energy storage converter 1 is greater than the second preset adjustment power, the current operating power of the energy storage converter 1 is reduced by the second preset adjustment power.

[0172] S324: Determine whether the total power of the user grid bus 5 is greater than or equal to the fifth preset power and less than or equal to the fourth preset power.

[0173] S325: When the determination is yes, that is, the total power of the user grid bus 5 is greater than or equal to the fifth preset power and less than or equal to the fourth preset power, the current operating power of the energy storage converter 1 is kept unchanged.

[0174] S326: Determine whether the remaining power of the energy storage unit 2 is less than a preset lower limit. Specifically, the preset lower limit may be the power when the energy storage unit 2 is fully discharged normally. If the remaining power of the energy storage unit 2 is less than the preset lower limit, overdischarge may occur.

[0175] S327: cyclically executing the above steps at least once at a second preset time interval until the remaining power of the energy storage unit 2 is less than a preset lower limit power.

[0176] S328: When the remaining power of the energy storage unit 2 is less than the preset lower limit, the energy storage converter 1 is controlled to stop and wait. That is, when the energy storage unit 2 is fully discharged, the energy storage converter 1 is controlled to stop and wait, and no longer discharges the energy storage unit 2 to avoid over-discharge.

[0177] The specific contents of steps S320 to S328 have been described in detail above and will not be repeated here. It should be noted that, for step S327, in some embodiments, steps S320 to S326 can be cyclically executed at a first preset time interval, and steps S100 and S200 are performed in real time, and the time intervals for their execution are different from the first preset time interval. For step S327, in some embodiments, steps S100 to S200 and steps S320 to S326 can be cyclically executed at a first preset time interval. It should also be noted that the order of steps S320 to S326 is not absolute, and those skilled in the art can adjust it as needed. Steps S320, S322, and S325 can be performed sequentially or simultaneously.

[0178] Furthermore, before step S300, the energy storage control method further includes:

[0179] S500: When the current time is in the preset discharge period, determine whether the total power of the user power grid bus 5 is less than or equal to a sixth preset power;

[0180] S510: When the total power of the user grid bus 5 is less than or equal to the sixth preset power, control the energy storage converter 1 to stop and wait;

[0181] S520: When the total power of the user grid bus 5 is greater than the sixth preset power, the operating power of the energy storage converter 1 is adjusted according to the total power of the user grid bus 5, so that the total power of the user grid bus 5 is stabilized within the preset power range until the remaining power of the energy storage unit 2 meets the preset requirements.

[0182] The sixth preset power is the protection power of the transformer 8, and the sixth preset power is less than the fifth preset power. In other words, when the total power of the user grid bus 5 is too low, the energy storage converter 1 is controlled to shut down and wait to ensure that the transformer 8 can operate safely and stably.

[0183] Refer to the attached Figure 3 An energy storage control method in a specific embodiment of the present invention is exemplarily described. The energy storage control method may be based on the above-mentioned energy storage control system and includes the following steps:

[0184] Determine whether the current time belongs to the preset charging period or the preset discharging period.

[0185] When the current time falls within the preset charging period, the energy storage converter 1 (PCS) starts charging the energy storage unit 2. That is, the control unit 4 controls the energy storage converter 1 to convert the AC power from the user grid bus 5 into DC power to charge the energy storage unit 2.

[0186] Obtain the total power (Pn) of the user power grid bus 5.

[0187] It is determined whether the total power (Pn) of the user power grid bus 5 is less than a third preset power (PLmax).

[0188] When the judgment is no, the energy storage converter 1 (PCS) is controlled to shut down and wait. When the judgment is yes, the relationship between the total power (Pn) of the user grid bus 5 and the first preset power (Pmax) and the second preset power (Pmax-Ps1) is judged, wherein the second preset power (Pmax-Ps1) = the first preset power (Pmax) - the first preset adjustment power (Ps1).

[0189] When the total power (Pn) of the user grid bus 5 is greater than the first preset power (Pmax), it is further determined whether the current operating power (Pt) of the energy storage converter 1 (PCS) is greater than the first preset adjustment power (Ps1). When the determination is yes, the current operating power (Pt) of the energy storage converter 1 (PCS) is reduced by the first preset adjustment power (Ps1).

[0190] When the total power (Pn) of the user grid bus 5 is less than the second preset power (Pmax-Ps1), it is further determined whether the current operating power (Pt) of the energy storage converter 1 (PCS) is less than the first set operating power (Px1). When the determination is yes, the current operating power (Pt) of the energy storage converter 1 (PCS) is increased by the first preset adjustment power (Ps1).

[0191] When the total power (Pn) of the user grid bus 5 is greater than or equal to the second preset power (Pmax-Ps1) and less than or equal to the first preset power (Pmax), the current operating power (Pt) of the energy storage converter 1 (PCS) is kept unchanged.

[0192] Determine whether the remaining capacity (SOC) of the energy storage unit 2 is greater than or equal to the preset upper limit capacity (SOCmax). When the determination is yes, control the energy storage converter 1 (PCS) to shut down and wait, and charging is completed; when the determination is no, the steps from obtaining the total power (Pn) of the user grid bus 5 to determining whether the remaining capacity (SOC) of the energy storage unit 2 is greater than or equal to the preset upper limit capacity (SOCmax) can be repeated after a first preset time interval, that is, the steps from obtaining the total power (Pn) of the user grid bus 5 to determining whether the remaining capacity (SOC) of the energy storage unit 2 is greater than or equal to the preset upper limit capacity (SOCmax) are cyclically executed at the first preset time interval until the remaining capacity (SOC) of the energy storage unit 2 is greater than or equal to the preset upper limit capacity (SOCmax).

[0193] When the current time falls within the preset discharge period, the energy storage converter 1 (PCS) starts discharging the energy storage unit 2. That is, the control unit 4 controls the energy storage converter 1 to convert the DC power from the energy storage unit 2 into AC power and transmit it to the user grid bus 5.

[0194] Obtain the total power (Pn) of the user power grid bus 5.

[0195] It is determined whether the total power (Pn) of the user power grid bus 5 is greater than a sixth preset power (PLmin).

[0196] When the judgment is no, the energy storage converter 1 (PCS) is controlled to shut down and wait. When the judgment is yes, the relationship between the total power (Pn) of the user grid bus 5 and the fourth preset power (Pmin+Ps2) and the fifth preset power (Pmin) is judged, wherein the fourth preset power (Pmin+Ps2)=fifth preset power (Pmin)+second preset adjustment power (Ps2).

[0197] When the total power (Pn) of the user grid bus 5 is greater than the fourth preset power (Pmin+Ps2), it is further judged whether the current operating power (Pt) of the energy storage converter 1 (PCS) is less than the second set operating power (Px2). When the judgment is yes, the current operating power (Pt) of the energy storage converter 1 (PCS) is increased by the second preset adjustment power (Ps2).

[0198] When the total power (Pn) of the user grid bus 5 is less than the fifth preset power (Pmin), it is further judged whether the current operating power (Pt) of the energy storage converter 1 (PCS) is greater than the second preset adjustment power (Ps2). When the judgment is yes, the current operating power (Pt) of the energy storage converter 1 (PCS) is reduced by the second preset adjustment power (Ps2).

[0199] When the total power (Pn) of the user grid bus 5 is greater than or equal to the fifth preset power (Pmin) and less than or equal to the fourth preset power (Pmin+Ps2), the current operating power (Pt) of the energy storage converter 1 (PCS) is kept unchanged.

[0200] Determine whether the remaining capacity (SOC) of the energy storage unit 2 is less than the preset lower capacity (SOCmin). When the determination is yes, control the energy storage converter 1 (PCS) to shut down and wait, and the discharge is completed. When the determination is no, the steps from obtaining the total power (Pn) of the user grid bus 5 to determining whether the remaining capacity (SOC) of the energy storage unit 2 is less than the preset lower capacity (SOCmin) can be repeated after a second preset time interval. That is, the steps from obtaining the total power (Pn) of the user grid bus 5 to determining whether the remaining capacity (SOC) of the energy storage unit 2 is less than the preset lower capacity (SOCmin) are cyclically executed at the second preset time interval until the remaining capacity (SOC) of the energy storage unit 2 is less than the preset lower capacity (SOCmin).

[0201] When the current time does not belong to the preset discharging period nor the preset charging period, the energy storage converter 1 (PCS) is controlled to stop and wait.

[0202] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely illustrative and are not intended to limit the scope of the present application. Various changes and modifications may be made therein by those skilled in the art without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0203] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0204] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, other division methods may be used. For example, multiple units or components may be combined or integrated into another device or unit, or some features may be ignored or not performed.

[0205] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0206] Similarly, it should be understood that in order to streamline the present application and aid in understanding one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, this approach of the present application should not be interpreted as reflecting the intention that the application claimed for protection requires more features than those explicitly recited in each claim. More precisely, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with fewer features than all the features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into the detailed description, with each claim itself serving as a separate embodiment of the present application.

[0207] Those skilled in the art will understand that, except where mutually exclusive, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or apparatus disclosed herein may be combined in any combination. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that provides the same, equivalent, or similar purpose.

[0208] Furthermore, those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, combinations of features from different embodiments are intended to be within the scope of this application and to form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

[0209] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims.

Claims

1. An energy storage system, characterized in that: It includes an energy storage converter, an energy storage unit, a power detection unit and a control unit; The AC side of the energy storage converter is connected to the user grid bus, and the DC side of the energy storage converter is connected to the energy storage unit. The energy storage converter is used to control the charging and discharging process of the energy storage unit; The power detection unit is used to obtain the total power of the user power grid bus; The control unit is connected to the power detection unit, the energy storage converter, and the energy storage unit. The control unit is used to determine whether the current time is in a preset charging period or a preset discharging period. During the preset charging period or the preset discharging period, the control unit adjusts the operating power of the energy storage converter according to the total power of the user grid bus, so that the total power of the user grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets the preset requirement. Wherein, when the current time is within the preset charging period, adjusting the operating power of the energy storage converter according to the total power of the user grid bus so that the total power of the user grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets the preset requirement includes: Determining whether the total power of the user grid bus is greater than a first preset power and the current operating power of the energy storage converter is greater than a first preset adjustment power; When the determination is yes, reducing the current operating power of the energy storage converter by the first preset adjustment power; Determining whether the total power of the user grid bus is less than a second preset power and the current operating power of the energy storage converter is less than a first set operating power of the energy storage converter, wherein the first preset power is greater than the second preset power; When the determination is yes, increasing the current operating power of the energy storage converter by the first preset adjustment power; Determining whether the total power of the user power grid bus is greater than or equal to the second preset power and less than or equal to the first preset power; When the determination is yes, maintaining the current operating power of the energy storage converter unchanged; Determining whether the remaining power of the energy storage unit is greater than or equal to a preset upper limit power; Repeating the above steps at least once at a first preset time interval until the remaining power of the energy storage unit is greater than or equal to the preset upper limit power; When the remaining power of the energy storage unit is greater than or equal to the preset upper limit power, the energy storage converter is controlled to stop and wait.

2. The energy storage system according to claim 1, characterized in that The user power grid bus is connected to the public power grid bus via a transformer; The power detection unit includes a power meter, which is arranged on a side of the transformer connected to the public grid bus.

3. The energy storage system according to claim 2, characterized in that: The control unit is used for: Determine whether the current time is in a preset charging period or a preset discharging period; When the current time is within the preset charging period, controlling the energy storage converter to convert the alternating current from the user grid bus into direct current to charge the energy storage unit; When the current time is within the preset discharge period, controlling the energy storage converter to convert the direct current from the energy storage unit into alternating current and transmit it to the user grid bus; When the current time is not within the preset charging period and the preset discharging period, the energy storage converter is controlled to stop and wait.

4. The energy storage system according to claim 2, characterized in that: At least one load is connected to the user power grid bus; The first preset adjustment power is 5%-20% of the capacity of the transformer or 110%-120% of the average fluctuation range of the total power of the load; The first preset time interval is 5-20 seconds; The difference between the first preset power and the second preset power is greater than or equal to the first preset adjustment power; The first set operating power is the rated operating power of the energy storage converter.

5. The energy storage system according to claim 1, characterized in that: The control unit is further configured to: When the current time is within the preset charging period and the total power of the user grid bus is greater than or equal to a third preset power, the energy storage converter is controlled to stop and wait, wherein the third preset power is greater than the first preset power.

6. The energy storage system according to claim 3, characterized in that: When the current time is within the preset discharge period, adjusting the operating power of the energy storage converter according to the total power of the user grid bus so that the total power of the user grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets the preset requirement includes: Determining whether the total power of the user grid bus is greater than a fourth preset power and the current operating power of the energy storage converter is less than a second set operating power of the energy storage converter; When the determination is yes, increasing the current operating power of the energy storage converter by a second preset adjustment power; Determining whether the total power of the user grid bus is less than a fifth preset power and the current operating power of the energy storage converter is greater than the second preset adjustment power, wherein the fourth preset power is greater than the fifth preset power; When the determination is yes, reducing the current operating power of the energy storage converter by the second preset adjustment power; Determining whether the total power of the user power grid bus is greater than or equal to the fifth preset power and less than or equal to the fourth preset power; When the determination is yes, maintaining the current operating power of the energy storage converter unchanged; Determining whether the remaining power of the energy storage unit is less than a preset lower limit power; Repeating the above steps at least once at a second preset time interval until the remaining power of the energy storage unit is less than the preset lower limit power; When the remaining power of the energy storage unit is less than the preset lower limit power, the energy storage converter is controlled to stop and wait.

7. The energy storage system according to claim 6, characterized in that: At least one load is connected to the user power grid bus; The second preset regulated power is 110%-120% of the average fluctuation range of the total power of the load; The second preset time interval is 5-20 seconds; The difference between the fourth preset power and the fifth preset power is greater than or equal to the second preset adjustment power; The second set operating power is the rated operating power of the energy storage converter.

8. The energy storage system according to claim 6, characterized in that: The control unit is further configured to: When the current time is in the preset discharge period and the total power of the user grid bus is less than or equal to a sixth preset power, the energy storage converter is controlled to shut down and wait, wherein the sixth preset power is less than the fifth preset power.

9. The energy storage system according to claim 1, characterized in that: The energy storage unit includes a battery management system and a battery pack; or, The energy storage unit includes a supercapacitor array.

10. A method for controlling energy storage, characterized in that: include: Determine whether the current time belongs to a preset charging period or a preset discharging period; When the current time belongs to the preset charging period or the preset discharging period, obtaining the total power of the user grid bus, wherein the user grid bus is connected to the AC side of the energy storage converter, and the DC side of the energy storage converter is connected to the energy storage unit; Adjusting the operating power of the energy storage converter according to the total power of the user grid bus, so that the total power of the user grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets the preset requirements; in, When the current time falls within the preset charging period, adjusting the operating power of the energy storage converter according to the total power of the user grid bus to stabilize the total power of the user grid bus within a preset power range until the remaining power of the energy storage unit meets a preset requirement includes: Determining whether the total power of the user grid bus is greater than a first preset power and the current operating power of the energy storage converter is greater than a first preset adjustment power; When the determination is yes, reducing the current operating power of the energy storage converter by the first preset adjustment power; Determining whether the total power of the user grid bus is less than a second preset power and the current operating power of the energy storage converter is less than a first set operating power of the energy storage converter, wherein the first preset power is greater than the second preset power; When the determination is yes, increasing the current operating power of the energy storage converter by the first preset adjustment power; Determining whether the total power of the user power grid bus is greater than or equal to the second preset power and less than or equal to the first preset power; When the determination is yes, maintaining the current operating power of the energy storage converter unchanged; Determining whether the remaining power of the energy storage unit is greater than or equal to a preset upper limit power; Repeating the above steps at least once at a first preset time interval until the remaining power of the energy storage unit is greater than or equal to the preset upper limit power; When the remaining power of the energy storage unit is greater than or equal to the preset upper limit power, the energy storage converter is controlled to stop and wait.

11. The energy storage control method according to claim 10, characterized in that At least one load is connected to the user power grid bus; The first preset regulated power is 110%-120% of the average fluctuation range of the total power of the load; The first preset time interval is 5-20 seconds; The difference between the first preset power and the second preset power is greater than or equal to the first preset adjustment power; The first set operating power is the rated operating power of the energy storage converter.

12. The energy storage control method according to claim 10, characterized in that The energy storage control method further includes: When the current time is within the preset charging period, determining whether the total power of the user power grid bus is greater than or equal to a third preset power, wherein the third preset power is greater than the first preset power; When the total power of the user grid bus is greater than or equal to the third preset power, controlling the energy storage converter to stop and wait; When the total power of the user grid bus is less than the third preset power, the operating power of the energy storage converter is adjusted according to the total power of the user grid bus, so that the total power of the user grid bus is stabilized within the preset power range until the remaining power of the energy storage unit meets the preset requirements.

13. The energy storage control method according to claim 10, characterized in that: When the current time is within the preset discharge period, adjusting the operating power of the energy storage converter according to the total power of the user grid bus so that the total power of the user grid bus is stabilized within a preset power range until the remaining power of the energy storage unit meets a preset requirement includes: Determining whether the total power of the user grid bus is greater than a fourth preset power and the current operating power of the energy storage converter is less than a second set operating power of the energy storage converter; When the determination is yes, increasing the current operating power of the energy storage converter by a second preset adjustment power; Determining whether the total power of the user grid bus is less than a fifth preset power and the current operating power of the energy storage converter is greater than the second preset adjustment power, wherein the fourth preset power is greater than the fifth preset power; When the determination is yes, reducing the current operating power of the energy storage converter by the second preset adjustment power; Determining whether the total power of the user power grid bus is greater than or equal to the fifth preset power and less than or equal to the fourth preset power; When the determination is yes, maintaining the current operating power of the energy storage converter unchanged; Determining whether the remaining power of the energy storage unit is less than a preset lower limit power; Repeating the above steps at least once at a second preset time interval until the remaining power of the energy storage unit is less than the preset lower limit power; When the remaining power of the energy storage unit is less than the preset lower limit power, the energy storage converter is controlled to stop and wait.

14. The energy storage control method according to claim 13, characterized in that: At least one load is connected to the user power grid bus; The second preset regulated power is 110%-120% of the average fluctuation range of the total power of the load; The second preset time interval is 5-20 seconds; The difference between the fourth preset power and the fifth preset power is greater than or equal to the second preset adjustment power; The second set operating power is the rated operating power of the energy storage converter.

15. The energy storage control method according to claim 13, characterized in that: The energy storage control method further includes: When the current time is in the preset discharge period, determining whether the total power of the user grid bus is less than or equal to a sixth preset power, wherein the sixth preset power is less than the fifth preset power; When the total power of the user grid bus is less than or equal to the sixth preset power, controlling the energy storage converter to stop and wait; When the total power of the user grid bus is greater than the sixth preset power, the operating power of the energy storage inverter is adjusted according to the total power of the user grid bus, so that the total power of the user grid bus is stabilized within the preset power range until the remaining power of the energy storage unit meets the preset requirements.

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