Control method of energy storage system, controller and energy storage system

Abstract

The invention provides a control method of an energy storage system, a controller and the energy storage system, and the method comprises the steps: obtaining the electrical parameters of a battery unit when the energy storage system is in a standby state; if the electrical parameter of the battery unit meets a first preset condition, controlling the direct current conversion circuit to stabilize voltage for the direct current bus; and if the electrical parameters of the battery unit do not meet the first preset condition, controlling the energy storage converter to stabilize voltage for the direct current bus. According to the method, the problem that the energy storage system cannot be started due to too low battery electric quantity caused by battery voltage stabilization during standby can be avoided, and the stability of the direct-current bus voltage of the energy storage system is maintained.

Description

Technical Field

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

[0002] In recent years, energy storage battery systems have developed rapidly, and are moving towards high capacity, high power density, and high power integration. Generally speaking, an energy storage system is often composed of multiple battery modules in parallel, and a battery module is composed of different numbers of single cells in series and parallel.

[0003] At present, when the energy storage system is in standby mode, the voltage of the DC bus needs to be stabilized at a certain value. Usually, a battery module is used to stabilize the DC bus voltage. This voltage stabilization method will continuously consume the power of the battery module. When the battery power is too low, the battery module cannot be started when it is turned on again, and long-term over-discharge will affect the battery life. Summary of the invention

[0004] The embodiments of the present invention provide a control method, a controller and an energy storage system for an energy storage system, so as to solve the problem of DC bus voltage stability when the energy storage system is in standby mode.

[0005] In a first aspect, an embodiment of the present invention provides a control method for an energy storage system, wherein the energy storage system includes an energy storage converter and a battery module; the battery module includes a battery unit and a DC conversion circuit; the power supply end of the battery unit is connected to the first end of the DC conversion circuit, and the second end of the DC conversion circuit is connected to the DC bus of the energy storage converter; the AC end of the energy storage converter is used to connect to a power grid; the method includes:

[0006] When the energy storage system is in a standby state, obtaining electrical parameters of the battery unit;

[0007] If the electrical parameters of the battery unit meet the first preset condition, controlling the DC conversion circuit to stabilize the DC bus;

[0008] If the electrical parameter of the battery unit does not meet the first preset condition, the energy storage converter is controlled to stabilize the DC bus.

[0009] In a second aspect, an embodiment of the present invention provides a controller comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method for controlling the energy storage system as described in any possible implementation of the first aspect above are implemented.

[0010] In a third aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the control method of the energy storage system as described in the first aspect or any possible implementation method of the first aspect are implemented.

[0011] In a fourth aspect, an embodiment of the present invention provides an energy storage system, comprising: an energy storage inverter, a battery module and a controller as described in the second aspect above; the battery module comprises a battery cell and a DC conversion circuit; the power supply end of the battery cell is connected to the first end of the DC conversion circuit, and the second end of the DC conversion circuit is connected to the DC bus of the energy storage inverter.

[0012] The embodiment of the present invention provides a control method, controller and energy storage system for an energy storage system. The method obtains the electrical parameters of the battery unit when the energy storage system is in a standby state; if the electrical parameters of the battery unit meet a first preset condition, the DC conversion circuit is controlled to stabilize the DC bus voltage; if the electrical parameters of the battery unit do not meet the first preset condition, the energy storage converter is controlled to stabilize the DC bus voltage. The above method can avoid the problem that the battery power is too low to start due to battery voltage stabilization when the energy storage system is in standby state, and maintain the stability of the DC bus voltage of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0014] Figure 1 is an application scenario diagram of the control method of the energy storage system provided by an embodiment of the present invention;

[0015] Figure 2 is a flow chart of an implementation method of a control method for an energy storage system provided by an embodiment of the present invention;

[0016] Figure 3 is a schematic structural diagram of a bidirectional DCDC circuit provided by an embodiment of the present invention;

[0017] Figure 4 is a schematic diagram of the structure of a control device for an energy storage system provided by an embodiment of the present invention;

[0018] Figure 5 is a schematic diagram of a controller provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below in conjunction with the accompanying drawings.

[0021] Figure 1 This is a schematic diagram of the structure of the energy storage system provided by an embodiment of the present invention. Figure 1 As shown, the energy storage system includes an energy storage inverter and at least one battery module; the battery module includes a battery unit and a DC conversion circuit; the power supply end of the battery unit is connected to the first end of the DC conversion circuit, and the second end of the DC conversion circuit is connected to the DC bus of the energy storage inverter; the AC end of the energy storage inverter is used to connect to the power grid.

[0022] The energy storage system also includes a monitoring host, which is used to monitor various devices in the energy storage system and generate corresponding control strategies to control the energy storage system. The executor of the control method of the energy storage system provided in this embodiment can be the monitoring host in the energy storage system.

[0023] See also Figure 2 , which shows a flow chart of the implementation of the control method of the energy storage system provided by the embodiment of the present invention, and is described in detail as follows:

[0024] S101: When the energy storage system is in a standby state, obtaining electrical parameters of the battery unit.

[0025] In this embodiment, when the entire energy storage system has neither a charging task nor a discharging task, it enters a standby state. When the energy storage system is in the standby state, the voltage of the DC bus needs to be stabilized within a certain range to ensure that the energy storage system can be quickly started when it works again. At present, when the energy storage system is in the standby state, the power of the battery unit is usually used to stabilize the DC bus voltage. However, when the power of the battery unit is insufficient, not only can the DC bus voltage not be stabilized, but continuous DC bus voltage stabilization will also cause the battery unit to be exhausted. This will affect the life of the battery unit and cause the battery unit to be unable to start when working again.

[0026] In order to solve the above problem, this embodiment monitors the electrical parameters of the battery unit. When the electrical parameters do not meet the first preset condition, the DC bus is stabilized by the power grid to avoid the problem of unstable DC bus voltage and ensure the normal operation of the battery unit.

[0027] Specifically, the electrical parameters of the battery cell may include SOC (State of Charge), available remaining capacity and output voltage.

[0028] S102: If the electrical parameters of the battery unit meet a first preset condition, controlling the DC conversion circuit to stabilize the DC bus.

[0029] In this embodiment, if the electrical parameter is the battery output voltage, then if the battery output voltage of all battery cells is greater than the preset voltage threshold, it means that the capacity of the battery cell is high, and the battery cell can stabilize the DC bus voltage through the DC conversion circuit; if there is a battery cell whose battery output voltage is not greater than the preset voltage threshold, it means that there is a battery cell with a small capacity and cannot stabilize the DC bus voltage. At this time, the DC bus voltage can be supported by the power of the power grid. If the electrical parameter is the SOC value, then when it is monitored that the SOC values ​​of all battery cells are greater than the preset SOC threshold, the DC conversion circuit corresponding to each battery cell is controlled to stabilize the DC bus voltage; when it is monitored that the SOC value of a battery cell is not greater than the preset SOC threshold, the DC bus voltage is stabilized by the power of the power grid.

[0030] In a possible implementation, the DC conversion circuit is a bidirectional DCDC circuit with a flying capacitor; Figure 3 As shown, the bidirectional DCDC circuit includes charging tubes (Q3-D3, Q4-D4) and discharge tubes (Q1-D1, Q2-D2), and the flying capacitors are C1, C2 and C3. In this bidirectional DCDC circuit, when the low-voltage side is powered on and slowly started, the low-voltage side capacitor is slowly charged through the low-voltage side slow charging circuit, and the flying capacitor and the high-voltage side bus capacitor are slowly charged through the DCDC topology; when a black start is required, the DC contactor is attracted, and the external DC bus is slowly charged at the same time. The specific charging circuit includes: Charging circuit 1: charging C1 and C3 through L1, D3, C1, and D6. When the flying capacitor voltage is slowly charged to half of the input voltage, the flying capacitor voltage is maintained; Charging circuit 2: slow charging C2 through L1, D3, and D4. In the slow-start state of power-on on the high-voltage side, the high-voltage side KM3 contactor is energized, and the low-voltage side capacitor is buffered through the low-voltage side buffer resistor. The specific charging circuits include: Charging circuit 1: C1 and C3 are charged through L1, D3, C1, and D6. When the flying capacitor voltage is slowly charged to half of the input voltage, the flying capacitor voltage is maintained; Charging circuit 2: C2 is slowly charged through L1, D3, and D4.

[0031] Based on the above circuit structure, the specific implementation process of S102 further includes:

[0032] If the battery cell is in a charge-forbidden state and the available remaining capacity of the battery cell is greater than a preset power threshold, the DC conversion circuit is controlled to operate in a constant voltage operation mode, the driving of the charging tube in the bidirectional DC conversion circuit is blocked, and the discharge tube in the DC conversion circuit is driven to operate;

[0033] If the battery cell is in a prohibited discharge state and the available remaining capacity of the battery cell is greater than a preset power threshold, the DC conversion circuit is controlled to operate in a constant voltage working mode, the discharge tube in the bidirectional DC conversion circuit is blocked from driving, and the charging tube in the DC conversion circuit is driven to operate.

[0034] In this embodiment, after the battery unit is discharged normally until the controller issues a discharge prohibition instruction, the bidirectional DCDC circuit will block the drive and standby operation. At this time, the bidirectional DCDC circuit operates in a constant voltage working mode, that is, provides a constant voltage value to stabilize the DC bus voltage. In the constant voltage working mode, since the bidirectional DCDC circuit has blocked the pulse, the bidirectional DCDC circuit stabilizes the DC bus voltage at a certain value, but since the buses between the bidirectional DCDC circuits are connected in parallel, and there are differences between the bus current samplings, according to the bus current equalization strategy, the bidirectional DCDC circuit with a low bus current sampling will raise its own bus voltage to increase the bus current. At this time, the battery will continue to output discharge current to ensure bus current equalization; causing the low-voltage battery to continue to pump current into other batteries until the battery is depleted.

[0035] In order to ensure that the bidirectional DCDC circuit does not discharge after the discharge is prohibited and does not charge after the charging is prohibited, so as to prevent the battery from being overcharged or over-discharged, the controller of this embodiment blocks the charging tube of the bidirectional DCDC circuit after receiving the charging prohibition instruction, and controls the normal operation of the discharge tube, and realizes the stability of the flying capacitor through the stable flying loop; after receiving the discharge prohibition instruction, the discharge tube of the bidirectional DCDC circuit is blocked, and the charging tube operates normally, and realizes the stability of the flying capacitor through the stable flying loop. Through the above scheme, this embodiment can not only avoid the problem of battery overcharge or over-discharge, but also effectively stabilize the DC bus voltage through multiple battery units.

[0036] In a possible implementation, the electrical parameter includes available remaining capacity; the specific implementation process of S102 includes:

[0037] If the available remaining capacity of the battery unit is greater than a preset power threshold, the DC conversion circuit is controlled to operate in a constant voltage working mode so that the DC conversion circuit stabilizes the DC bus.

[0038] In a possible implementation, the battery module includes a plurality of battery modules, and the power supply end of the battery unit in each battery module is connected to the first end of the corresponding DC conversion circuit, and the second end of each DC conversion circuit is connected to the DC bus of the energy storage converter; the specific implementation process of S102 includes:

[0039] If the electrical parameters of all battery cells meet the first preset condition, the DC conversion circuit is controlled to stabilize the DC bus.

[0040] Specifically, when the available remaining capacity of all battery cells is greater than a preset power threshold, the corresponding DC conversion circuit is controlled to operate in a constant voltage working mode so that each battery cell stabilizes the DC bus.

[0041] S103: If the electrical parameters of the battery unit do not meet the first preset condition, control the energy storage converter to stabilize the DC bus.

[0042] In a possible implementation, the battery module includes multiple battery modules, and the power supply end of the battery unit in each battery module is connected to the first end of the corresponding DC conversion circuit, and the second end of each DC conversion circuit is connected to the DC bus of the energy storage converter; the specific implementation process of S103 includes:

[0043] If the electrical parameters of a battery unit do not satisfy the first preset condition, the energy storage converter is controlled to stabilize the DC bus.

[0044] In this embodiment, if there is a battery cell whose available remaining capacity is not greater than a preset power threshold, the charging tube and the discharging tube of the battery cell are blocked, and the number of battery cells that are prohibited from charging and discharging is monitored in real time. If the number of battery cells that are prohibited from charging and discharging is greater than the preset number threshold, the energy storage inverter is controlled to draw power from the power grid for DC bus voltage stabilization.

[0045] In this embodiment, if there is a small amount of battery cells with insufficient available remaining capacity, the battery cells are controlled to prohibit charging and discharging. At this time, most of the other battery cells are still operating in the constant voltage working mode. Since most of the other battery cells can still provide a constant voltage for the DC bus, although the DC bus voltage drops slightly, the bus voltage can still be stabilized at a certain value. Therefore, at this time, the bus voltage can be stabilized based on the power of the battery cells. If the number of battery cells prohibited from charging and discharging is greater than the preset number threshold, the DC bus voltage cannot be stabilized. At this time, the battery cells can be controlled to enter the prohibited charging and discharging state, and the energy storage inverter can be controlled to enter the constant voltage working mode of AC to DC, and the grid electrical signal is used to stabilize the DC bus voltage to ensure the stability of the DC bus voltage.

[0046] In a possible implementation manner, the specific implementation process of S103 further includes:

[0047] If the electrical parameter of the battery unit does not meet the first preset condition, the energy storage converter is controlled to operate in a constant voltage operating mode so that the energy storage converter stabilizes the DC bus.

[0048] In a possible implementation manner, another implementation process of S102 includes:

[0049] If the electrical parameter of the battery unit meets the first preset condition and the electricity price of the power grid is lower than the electricity price threshold, controlling the energy storage converter to stabilize the DC bus;

[0050] If the electrical parameter of the battery unit meets the first preset condition and the electricity price of the power grid is not lower than the electricity price threshold, the DC conversion circuit is controlled to stabilize the DC bus.

[0051] In this embodiment, on the premise that the electrical parameters of at least N battery cells meet the first preset condition, the DC bus voltage stabilization method can be determined according to the grid electricity price. When the grid electricity price is high, the power of the battery cells is consumed for DC bus voltage stabilization, and when the grid electricity price is low, the power of the grid is consumed for DC bus voltage stabilization, wherein N is the value obtained by subtracting the preset number threshold from the total number of battery cells in the energy storage system.

[0052] It can be seen from the above embodiments that the method provided in this embodiment can not only stabilize the DC bus voltage, but also reduce the cost of stabilizing the bus voltage.

[0053] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0054] The following is an embodiment of the device of the present invention. For details not described in detail therein, reference may be made to the corresponding method embodiment described above.

[0055] Figure 4 The following is a schematic diagram showing the structure of a control device for an energy storage system provided by an embodiment of the present invention. For ease of explanation, only the parts related to the embodiment of the present invention are shown, which are described in detail as follows:

[0056] like Figure 4 As shown, the control device 100 of the energy storage system includes:

[0057] An electrical parameter acquisition module 110, configured to acquire electrical parameters of the battery unit when the energy storage system is in a standby state;

[0058] A battery voltage stabilization module 120, configured to control the DC conversion circuit to stabilize the DC bus voltage if the electrical parameters of the battery unit meet a first preset condition;

[0059] The converter voltage stabilization module 130 is used to control the energy storage converter to stabilize the DC bus voltage if the electrical parameter of the battery unit does not meet the first preset condition.

[0060] In a possible implementation, the electrical parameter includes available remaining capacity; the battery voltage stabilization module 120 includes:

[0061] If the available remaining capacity of the battery unit is greater than a preset power threshold, the DC conversion circuit is controlled to operate in a constant voltage working mode so that the DC conversion circuit stabilizes the DC bus.

[0062] In a possible implementation, the DC conversion circuit is a bidirectional DCDC circuit with a flying capacitor; and the bidirectional DCDC circuit includes a charging tube and a discharging tube; the battery voltage stabilization module 120 further includes:

[0063] If the battery cell is in a charge-forbidden state and the available remaining capacity of the battery cell is greater than a preset power threshold, the DC conversion circuit is controlled to operate in a constant voltage operation mode, the driving of the charging tube in the bidirectional DC conversion circuit is blocked, and the discharge tube in the DC conversion circuit is driven to operate;

[0064] If the battery cell is in a prohibited discharge state and the available remaining capacity of the battery cell is greater than a preset power threshold, the DC conversion circuit is controlled to operate in a constant voltage working mode, the discharge tube in the bidirectional DC conversion circuit is blocked from driving, and the charging tube in the DC conversion circuit is driven to operate.

[0065] In a possible implementation, the battery module includes a plurality of battery modules, and the power supply end of the battery unit in each battery module is connected to the first end of the corresponding DC conversion circuit, and the second end of each DC conversion circuit is connected to the DC bus of the energy storage converter; the battery voltage stabilizing module 120 specifically includes:

[0066] If the electrical parameters of all battery cells meet the first preset condition, the DC conversion circuit is controlled to stabilize the DC bus.

[0067] In a possible implementation, the battery module includes multiple battery modules, and the power supply end of the battery unit in each battery module is connected to the first end of the corresponding DC conversion circuit, and the second end of each DC conversion circuit is connected to the DC bus of the energy storage converter; the converter voltage stabilizing module 130 includes:

[0068] If the electrical parameters of a battery unit do not satisfy the first preset condition, the energy storage converter is controlled to stabilize the DC bus.

[0069] In a possible implementation, the converter voltage stabilizing module 130 further includes:

[0070] If the electrical parameter of the battery unit does not meet the first preset condition, the energy storage converter is controlled to operate in a constant voltage operating mode so that the energy storage converter stabilizes the DC bus.

[0071] In a possible implementation, the battery voltage stabilization module 120 includes:

[0072] If the electrical parameter of the battery unit meets the first preset condition and the electricity price of the power grid is lower than the electricity price threshold, controlling the energy storage converter to stabilize the DC bus;

[0073] If the electrical parameter of the battery unit meets the first preset condition and the electricity price of the power grid is not lower than the electricity price threshold, the DC conversion circuit is controlled to stabilize the DC bus.

[0074] It can be seen from the above embodiments that the above device can avoid the problem that the energy storage system cannot be started due to low battery power caused by battery voltage stabilization when the energy storage system is in standby mode, and maintain the stability of the DC bus voltage of the energy storage system.

[0075] Figure 5 is a schematic diagram of a controller provided by an embodiment of the present invention. Figure 5 As shown, the controller 5 of this embodiment includes: a processor 50 and a memory 51. The memory 51 is used to store a computer program 52, and the processor 50 is used to call and run the computer program 52 stored in the memory 51 to perform the steps in the above-mentioned various energy storage system control method embodiments, such as Figure 2 Alternatively, the processor 50 is used to call and run the computer program 52 stored in the memory 51 to implement the functions of each module / unit in the above-mentioned device embodiments, such as Figure 4 The functions of the modules 110 to 130 are shown.

[0076] Exemplarily, the computer program 52 may be divided into one or more modules / units, which are stored in the memory 51 and executed by the processor 50 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 52 in the controller 5. For example, the computer program 52 may be divided into Figure 4 Modules 110 to 130 are shown.

[0077] The controller 5 may include, but is not limited to, a processor 50 and a memory 51. Those skilled in the art will appreciate that Figure 5 It is only an example of the controller 5 and does not constitute a limitation of the controller 5. The controller may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the controller may also include input and output devices, network access devices, buses, etc.

[0078] The processor 50 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0079] The memory 51 may be an internal storage unit of the controller 5, such as a hard disk or memory of the controller 5. The memory 51 may also be an external storage device of the controller 5, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the controller 5. Further, the memory 51 may include both an internal storage unit of the controller 5 and an external storage device. The memory 51 is used to store the computer program and other programs and data required by the controller. The memory 51 may also be used to temporarily store data that has been output or is to be output.

[0080] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0081] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0082] 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 to be beyond the scope of the present invention.

[0083] In the embodiments provided by the present invention, it should be understood that the disclosed devices / controllers and methods can be implemented in other ways. For example, the device / controller embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0084] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0085] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0086] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the control method embodiments of the above-mentioned energy storage system can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0087] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A control method for an energy storage system, characterized in that: The energy storage system includes an energy storage converter and a battery module; the battery module includes a battery unit and a DC conversion circuit; the power supply end of the battery unit is connected to the first end of the DC conversion circuit, and the second end of the DC conversion circuit is connected to the DC bus of the energy storage converter; the AC end of the energy storage converter is used to connect to the power grid; The method comprises: When the energy storage system is in a standby state, obtaining electrical parameters of the battery unit; If the electrical parameters of the battery unit meet the first preset condition, controlling the DC conversion circuit to stabilize the DC bus; If the electrical parameter of the battery unit does not meet the first preset condition, the energy storage converter is controlled to stabilize the DC bus.

2. The control method of the energy storage system according to claim 1, characterized in that: The electrical parameter includes available remaining capacity; if the electrical parameter of the battery unit meets a first preset condition, controlling the DC conversion circuit to stabilize the DC bus, comprising: If the available remaining capacity of the battery unit is greater than a preset power threshold, the DC conversion circuit is controlled to operate in a constant voltage working mode so that the DC conversion circuit stabilizes the DC bus.

3. The control method of the energy storage system according to claim 2, characterized in that: The DC conversion circuit is a bidirectional DCDC circuit with a flying capacitor; and the bidirectional DCDC circuit includes a charging tube and a discharging tube; If the available remaining capacity of the battery unit is greater than a preset power threshold, the DC conversion circuit is controlled to operate in a constant voltage working mode so that the DC conversion circuit stabilizes the DC bus, including: If the battery cell is in a charge-forbidden state and the available remaining capacity of the battery cell is greater than a preset power threshold, the DC conversion circuit is controlled to operate in a constant voltage operation mode, the driving of the charging tube in the bidirectional DC conversion circuit is blocked, and the discharge tube in the DC conversion circuit is driven to operate; If the battery cell is in a prohibited discharge state and the available remaining capacity of the battery cell is greater than a preset power threshold, the DC conversion circuit is controlled to operate in a constant voltage working mode, the discharge tube in the bidirectional DC conversion circuit is blocked from driving, and the charging tube in the DC conversion circuit is driven to operate.

4. The control method of the energy storage system according to claim 1, characterized in that: The battery module includes a plurality of battery modules, and the power supply end of the battery unit in each battery module is connected to the first end of the corresponding DC conversion circuit, and the second end of each DC conversion circuit is connected to the DC bus of the energy storage converter; If the electrical parameter of the battery unit meets the first preset condition, controlling the DC conversion circuit to stabilize the DC bus voltage includes: If the electrical parameters of all battery cells meet the first preset condition, the DC conversion circuit is controlled to stabilize the DC bus.

5. The control method of the energy storage system according to claim 1, characterized in that: The battery module includes a plurality of battery modules, and the power supply end of the battery unit in each battery module is connected to the first end of the corresponding DC conversion circuit, and the second end of each DC conversion circuit is connected to the DC bus of the energy storage converter; If the electrical parameter of the battery unit does not meet the first preset condition, controlling the energy storage converter to stabilize the DC bus voltage includes: If the electrical parameters of a battery unit do not satisfy the first preset condition, the energy storage converter is controlled to stabilize the DC bus.

6. The control method of the energy storage system according to claim 1, characterized in that: If the electrical parameter of the battery unit does not meet the first preset condition, controlling the energy storage converter to stabilize the DC bus voltage includes: If the electrical parameter of the battery unit does not meet the first preset condition, the energy storage converter is controlled to operate in a constant voltage operating mode so that the energy storage converter stabilizes the DC bus.

7. The control method of the energy storage system according to claim 1, characterized in that: If the electrical parameter of the battery unit meets the first preset condition, controlling the DC conversion circuit to stabilize the DC bus voltage includes: If the electrical parameter of the battery unit meets the first preset condition and the electricity price of the power grid is lower than the electricity price threshold, controlling the energy storage converter to stabilize the DC bus; If the electrical parameter of the battery unit meets the first preset condition and the electricity price of the power grid is not lower than the electricity price threshold, the DC conversion circuit is controlled to stabilize the DC bus.

8. A controller, characterized in that: It comprises a processor and a memory, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the control method of the energy storage system as described in any one of claims 1 to 7.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for controlling the energy storage system as described in any one of claims 1 to 7 are implemented.

10. An energy storage system, characterized in that: include: An energy storage inverter, a battery module and a controller as claimed in claim 8; the battery module includes a battery unit and a DC conversion circuit; the power supply end of the battery unit is connected to the first end of the DC conversion circuit, and the second end of the DC conversion circuit is connected to the DC bus of the energy storage inverter.

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