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

Abstract

The application provides a control method of an energy storage system, a controller and the energy storage system. The method comprises: obtaining an electrical parameter 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 a direct-current conversion circuit to stabilize a direct-current bus; and if the electrical parameter of the battery unit does not meet the first preset condition, controlling an energy storage converter to stabilize the direct-current bus. The method can avoid the problem that the battery cannot be started due to the low battery power caused by the battery stabilization when the energy storage system is in the standby state, and maintain the stability of the direct-current bus voltage of the energy storage system.

Description

TECHNICAL FIELD

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

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

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

[0004] The embodiments of the present application provide a control method of an energy storage system, a controller and the energy storage system to solve the problem of stabilizing the voltage of the DC bus when the energy storage system is in standby.

[0005] In a first aspect, the embodiments of the present application provide a control method of an energy storage system, the energy storage system comprising an energy storage converter and a battery module; the battery module comprising a battery unit and a DC conversion circuit; the power supply end of the battery unit being connected with the first end of the DC conversion circuit, and the second end of the DC conversion circuit being connected with the DC bus of the energy storage converter; the AC end of the energy storage converter being used to connect the power grid; and the method comprising:

[0006] acquiring the electrical parameters of the battery unit when the energy storage system is in standby state;

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

[0008] if the electrical parameters of the battery unit do not meet the first preset condition, controlling the energy storage converter to stabilize the voltage of the DC bus.

[0009] In a second aspect, the embodiments of the present application provide a controller comprising a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the control method of the energy storage system according to any possible implementation manner of the first aspect.

[0010] In a third aspect, an embodiment of the present application provides a computer readable storage medium storing a computer program, the computer program, when executed by a processor, implements the steps of the control method of the energy storage system according to the first aspect or any possible implementation manner of the first aspect.

[0011] In a fourth aspect, an embodiment of the present application provides an energy storage system, comprising: an energy storage converter, a battery module, and a controller according to the second aspect; the battery module comprises a battery cell and a direct current conversion circuit; a power supply end of the battery cell is connected with a first end of the direct current conversion circuit, and a second end of the direct current conversion circuit is connected with a direct current bus of the energy storage converter.

[0012] The embodiment of the present application provides a control method of an energy storage system, a controller and the energy storage system. The method acquires an electrical parameter of the battery cell when the energy storage system is in a standby state; controls the direct current conversion circuit to stabilize the direct current bus if the electrical parameter of the battery cell meets a first preset condition; and controls the energy storage converter to stabilize the direct current bus if the electrical parameter of the battery cell does not meet the first preset condition. The above method can avoid the problem that the battery cannot be started due to the low battery power caused by the battery stabilization when the energy storage system is in standby, and maintain the stability of the direct current bus voltage of the energy storage system. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

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

[0015] Figure 2 is a flowchart of the control method of the energy storage system provided by the embodiment of the present application;

[0016] Figure 3 is a structure schematic diagram of the bidirectional DCDC circuit provided by the embodiment of the present application;

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

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

[0019] In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, technologies, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

[0020] In order to make the objects, technical solutions and advantages of the present application clearer, the following will be described by specific embodiments in conjunction with the accompanying drawings.

[0021] Figure 1 The structural schematic diagram of the energy storage system provided by the embodiments of the present application is shown in FIG. 1. Figure 1 As shown in the figure, the energy storage system comprises an energy storage converter and at least one battery module; the battery module comprises a battery cell and a direct current conversion circuit; the power supply end of the battery cell is connected with the first end of the direct current conversion circuit, and the second end of the direct current conversion circuit is connected with the direct current bus of the energy storage converter; and the alternating current end of the energy storage converter is used for connecting the power grid.

[0022] The energy storage system further comprises a monitoring host, which is used for monitoring each device in the energy storage system and generating a corresponding control strategy to control the energy storage system. The execution subject of the control method of the energy storage system provided by the embodiments of the present application can be the monitoring host in the energy storage system.

[0023] Referring to Figure 2 FIG. 2 shows the implementation flowchart of the control method of the energy storage system provided by the embodiments of the present application, which is described in detail as follows:

[0024] S101: When the energy storage system is in a standby state, the electrical parameter of the battery cell is acquired.

[0025] In the embodiments, when the whole energy storage system has neither a charging task nor a discharging task, it enters the standby state. When the energy storage system is in the standby state, the voltage of the direct current bus needs to be stabilized in a certain range to ensure that the energy storage system can be started quickly when it works again. At present, the electrical quantity of the battery cell is usually used for stabilizing the voltage of the direct current bus when the energy storage system is in the standby state. However, when the electrical quantity of the battery cell is insufficient, not only the voltage of the direct current bus cannot be stabilized, but also the continuous voltage stabilization of the direct current bus will lead to the depletion of the electrical quantity of the battery cell. Thus, the service life of the battery cell will be affected, and the battery cell cannot be started when it works again.

[0026] In order to solve the above problems, the electrical parameter of the battery cell is monitored in the embodiments. When the electrical parameter does not satisfy the first preset condition, the voltage of the direct current bus is stabilized by the power grid, so as to avoid the problem of unstable voltage of the direct current bus and ensure the normal work of the battery cell.

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

[0028] S102: If the electrical parameters of the battery cell meet the first preset condition, then control the DC-DC converter circuit to stabilize the DC bus voltage.

[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 a preset voltage threshold, it indicates that the battery cell capacity is high, and the battery cell can be used to stabilize the DC bus voltage through the DC-DC converter circuit. If the battery output voltage of some battery cells is not greater than the preset voltage threshold, it indicates that the battery cell capacity is small and cannot stabilize the DC bus voltage. In this case, the DC bus voltage can be supported by grid power. If the electrical parameter is the SOC value, then when the SOC value of all battery cells is detected to be greater than the preset SOC threshold, the DC-DC converter circuit corresponding to each battery cell is controlled to stabilize the DC bus voltage; when the SOC value of some battery cells is detected to be less than the preset SOC threshold, the DC bus voltage is stabilized by grid power.

[0030] In one possible implementation, the DC-DC converter circuit is a bidirectional DC-DC circuit with a flying capacitor; such as Figure 3 As shown, the bidirectional DC-DC circuit includes charging transistors (Q3-D3, Q4-D4) and discharging transistors (Q1-D1, Q2-D2), with flying capacitors C1, C2, and C3. In this bidirectional DC-DC circuit, during the low-voltage side power-on soft-start state, the low-voltage side capacitors are soft-charged through the low-voltage side soft-charging circuit, while the flying capacitors and high-voltage side bus capacitors are soft-charged through the DC-DC topology. When a black start is required, the DC contactor is engaged, simultaneously soft-charging the external DC bus. Specifically, the charging circuits include: Charging circuit 1: charging C1 and C3 through L1, D3, C1, and D6; when the flying capacitor voltage is soft-charged to half the input voltage, the flying capacitor voltage is maintained; Charging circuit 2: soft-charging C2 through L1, D3, and D4. In the high-voltage side power-on soft start state, 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 circuit includes: 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 unit is in the forbidden charging state and 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, the drive of the charging tube in the bidirectional DC conversion circuit is blocked, and the discharge tube in the DC conversion circuit is driven to work.

[0033] If the battery unit is in the forbidden discharging state and 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, the drive of the discharge tube in the bidirectional DC conversion circuit is blocked, and the charging tube in the DC conversion circuit is driven to work.

[0034] In the embodiment, after the battery unit normally discharges until the controller issues a forbidden discharging instruction, the bidirectional DCDC circuit blocks the drive and operates in standby mode. At this time, the bidirectional DCDC circuit operates in a constant voltage working mode, that is, a constant voltage value is provided 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. However, since the bidirectional DCDC circuits are connected in parallel between the buses, and there is a difference between the bus current samples, according to the bus current sharing strategy, the bidirectional DCDC circuit with low bus current sample will raise its bus voltage to increase the bus current. At this time, the battery will continuously output the discharging current to ensure the bus current sharing. This results in that the low-voltage battery continuously supplies the discharging current to other batteries until the battery is depleted.

[0035] In order to ensure that the bidirectional DCDC circuit does not discharge after being forbidden to discharge and does not charge after being forbidden to charge, and prevent the overcharging and overdischarging of the battery, the controller of the embodiment blocks the charging tube of the bidirectional DCDC circuit after receiving the forbidden charging instruction, and controls the discharge tube to normally operate, stabilizes the flying capacitor through the stable flying capacitor loop, and realizes the stabilization of the flying capacitor. After receiving the forbidden discharging instruction, the discharge tube of the bidirectional DCDC circuit is blocked, and the charging tube normally operates, the flying capacitor is stabilized through the stable flying capacitor loop, and the flying capacitor is stabilized. Through the above scheme, the embodiment can not only avoid the problem of overcharging or overdischarging of the battery, but also effectively stabilize the DC bus voltage through multiple battery units.

[0036] In a possible implementation manner, the electrical parameter includes the available remaining capacity; and 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 voltage.

[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 a corresponding direct-current conversion circuit, and the second end of each direct-current conversion circuit is connected to the direct-current bus of the energy storage converter; the specific implementation process of S102 includes:

[0039] If the electrical parameters of all the battery units satisfy the first preset condition, the direct-current conversion circuit is controlled to stabilize the voltage of the direct-current bus.

[0040] Specifically, when the available residual capacity of all the battery units is greater than the preset power threshold, the corresponding direct-current conversion circuit is controlled to operate in the constant-voltage working mode, so that each battery unit stabilizes the voltage of the direct-current bus.

[0041] S103: If the electrical parameters of the battery units do not satisfy the first preset condition, the energy storage converter is controlled to stabilize the voltage of the direct-current bus.

[0042] 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 a corresponding direct-current conversion circuit, and the second end of each direct-current conversion circuit is connected to the direct-current bus of the energy storage converter; the specific implementation process of S103 includes:

[0043] If the electrical parameters of the battery units do not satisfy the first preset condition, the energy storage converter is controlled to stabilize the voltage of the direct-current bus.

[0044] In this embodiment, if the available residual capacity of a battery unit is not greater than the preset power threshold, the charging pipe and the discharging pipe of the battery unit are blocked, and the number of the battery units that are forbidden to charge and discharge is monitored in real time. If the number of the battery units that are forbidden to charge and discharge is greater than a preset number threshold, the energy storage converter is controlled to take power from the power grid to stabilize the voltage of the direct-current bus.

[0045] In this embodiment, if the available residual capacity of a small number of battery units is insufficient, the battery units are controlled to be forbidden to charge and discharge. At this time, most of the other battery units still operate in the constant-voltage working mode. Since the most of the other battery units can still provide a constant voltage for the direct-current bus, although the voltage of the direct-current bus slightly decreases, the voltage of the bus can still be stabilized at a certain value. Therefore, at this time, the voltage of the bus can still be stabilized based on the power of the battery units. If the number of the battery units that are forbidden to charge and discharge is greater than the preset number threshold, the voltage of the direct-current bus cannot be stabilized. At this time, the battery units can be controlled to enter the state of being forbidden to charge and discharge, and the energy storage converter is controlled to enter the constant-voltage working mode of alternating current to direct current, so that the power grid electrical signal is used to stabilize the voltage of the direct-current bus, to ensure the voltage stability of the direct-current bus.

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

[0047] If the electrical parameter of the battery unit does not satisfy the first preset condition, the control device controls the energy storage converter to work in a constant voltage mode to stabilize the DC bus voltage.

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

[0049] If the electrical parameter of the battery unit satisfies the first preset condition and the electricity price of the power grid is lower than the electricity price threshold, the control device controls the energy storage converter to stabilize the DC bus voltage.

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

[0051] In this embodiment, on the premise that the electrical parameter of at least N battery units satisfies the first preset condition, the DC bus voltage stabilization approach can be determined according to the electricity price of the power grid, that is, when the electricity price of the power grid is high, the electrical quantity of the battery unit is consumed to stabilize the DC bus voltage, and when the electricity price of the power grid is low, the power grid is consumed to stabilize the DC bus voltage, where N is a value obtained by subtracting a preset quantity threshold from the total number of battery units in the energy storage system.

[0052] As can be seen from the above embodiment, 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 size of the serial number of each step in the above embodiment does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0054] The following is a device embodiment of the present application. For details not described in detail, reference can be made to the corresponding method embodiments described above.

[0055] Figure 4 The structure schematic diagram of the control device of the energy storage system provided in the embodiment of the present application is shown. For ease of illustration, only the parts related to the embodiment of the present application are shown, and the details are as follows:

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

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

[0058] The battery voltage stabilizing module 120 is configured to control the DC conversion circuit to stabilize the DC bus voltage if the electrical parameter of the battery unit meets the first preset condition.

[0059] The converter voltage stabilizing module 130 is configured 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; and the battery voltage stabilizing module 120 includes:

[0061] The battery voltage stabilizing module 120 is configured to control the DC conversion circuit to operate in a constant voltage mode to stabilize the DC bus voltage if the available remaining capacity of the battery unit is greater than the preset power threshold.

[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; and the battery voltage stabilizing module 120 further includes:

[0063] The battery voltage stabilizing module 120 is configured to control the DC conversion circuit to operate in a constant voltage mode, block the driving of the charging tube in the bidirectional DC conversion circuit, and drive the discharging tube in the DC conversion circuit to work if the battery unit is in a charging prohibited state and the available remaining capacity of the battery unit is greater than the preset power threshold.

[0064] The battery voltage stabilizing module 120 is configured to control the DC conversion circuit to operate in a constant voltage mode, block the driving of the discharging tube in the bidirectional DC conversion circuit, and drive the charging tube in the DC conversion circuit to work if the battery unit is in a discharging prohibited state and the available remaining capacity of the battery unit is greater than the preset power threshold.

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

[0066] The battery voltage stabilizing module 120 is configured to control the DC conversion circuit to stabilize the DC bus voltage if the electrical parameter of all the battery units meets the first preset condition.

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

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

[0069] In one possible implementation, the converter voltage regulator module 130 further includes:

[0070] If the electrical parameters of the battery cell do not meet the first preset condition, the energy storage converter is controlled to operate in constant voltage mode so that the energy storage converter can stabilize the DC bus voltage.

[0071] In one possible implementation, the battery voltage regulator module 120 includes:

[0072] If the electrical parameters of the battery cell meet the first preset condition and the electricity price of the power grid is lower than the electricity price threshold, then the energy storage converter is controlled to stabilize the DC bus voltage.

[0073] If the electrical parameters of the battery cell meet the first preset condition and the electricity price of the power grid is not lower than the electricity price threshold, then the DC-DC converter circuit is controlled to stabilize the DC bus voltage.

[0074] As can be seen from the above embodiments, the above device can avoid the problem that the battery power is too low and cannot start when the energy storage system is in standby mode due to the battery voltage being constantly regulated, and maintain the stability of the DC bus voltage of the energy storage system.

[0075] Figure 5 This is a schematic diagram of the controller provided in an embodiment of the present invention. Figure 5 As shown, the controller 5 in this embodiment includes a processor 50 and a memory 51. The memory 51 stores a computer program 52, and the processor 50 calls and runs the computer program 52 stored in the memory 51 to execute the steps in the control method embodiments of the various energy storage systems described above, for example... Figure 2 The steps S101 to S103 are shown. 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-described device embodiments, for example... Figure 4 The functions of modules 110 to 130 are shown.

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

[0077] The controller 5 can include, but not limited to, a processor 50, a memory 51. Those skilled in the art can understand that, Figure 5 The controller 5 is only an example and does not constitute a limitation on the controller 5, and can include more or less components than the illustration, or combine certain components, or different components, for example, the controller can also include an input / output device, a network access device, a bus, etc.

[0078] The processor 50 can be a central processing unit (CPU), and can also be 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. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0079] The memory 51 can be an internal storage unit of the controller 5, such as a hard disk or a memory of the controller 5. The memory 51 can 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. Further, the memory 51 can include both the internal storage unit and the external storage device of the controller 5. The memory 51 is used to store the computer program and other programs and data required by the controller. The memory 51 can also be used to temporarily store data that has been output or will be output.

[0080] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be realized in the form of hardware or software. In addition, the specific names of each functional unit and module are only for easy distinction, and do not limit the protection scope of the present application. The specific working process of the units and modules in the above system can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0081] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can be referred to the related description of other embodiments.

[0082] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0083] In the embodiments provided by the present application, it should be understood that the disclosed devices / controllers and methods can be implemented in other ways. For example, the above-described device / controller embodiments are only schematic. The division of the modules or units is only a logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or in other forms.

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

[0085] In addition, each function unit in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software function unit.

[0086] The integrated module / unit, if realized in the form of a software function unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above-mentioned embodiment methods can also be completed by a computer program instructing related hardware, and the computer program can be stored in a computer-readable storage medium. When the processor executes the computer program, the steps of the above-mentioned energy storage system control method embodiments can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or some intermediate forms, etc. The computer-readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included 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, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0087] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A control method of an energy storage system, characterized by, The energy storage system comprises an energy storage converter and a battery module; the battery module comprises a battery cell and a direct-current conversion circuit; a power supply end of the battery cell is connected with a first end of the direct-current conversion circuit, and a second end of the direct-current conversion circuit is connected with a direct-current bus of the energy storage converter; and an alternating-current end of the energy storage converter is used for connecting a power grid. The method comprises: When the energy storage system is in a standby state, acquiring an electrical parameter of the battery cell; If the electrical parameter of the battery cell meets a first preset condition, controlling the direct-current conversion circuit to stabilize the direct-current bus; If the electrical parameter of the battery cell does not meet the first preset condition, controlling the energy storage converter to stabilize the direct-current bus.

2. The control method of an energy storage system according to claim 1, wherein The electrical parameter comprises available residual capacity; and if the electrical parameter of the battery cell meets the first preset condition, controlling the direct-current conversion circuit to stabilize the direct-current bus comprises: If the available residual capacity of the battery cell is greater than a preset electrical capacity threshold, controlling the direct-current conversion circuit to operate in a constant-voltage working mode, so that the direct-current conversion circuit stabilizes the direct-current bus.

3. The control method of an energy storage system according to claim 2, wherein The direct-current conversion circuit is a bidirectional DCDC circuit with a flying capacitor; and the bidirectional DCDC circuit comprises a charging tube and a discharging tube; If the available residual capacity of the battery cell is greater than a preset electrical capacity threshold, controlling the direct-current conversion circuit to operate in a constant-voltage working mode, so that the direct-current conversion circuit stabilizes the direct-current bus comprises: If the battery cell is in a forbidden charging state and the available residual capacity of the battery cell is greater than a preset electrical capacity threshold, controlling the direct-current conversion circuit to operate in a constant-voltage working mode, blocking the drive of the charging tube in the bidirectional DCDC circuit, and driving the discharging tube in the bidirectional DCDC circuit to work; If the battery cell is in a forbidden discharging state and the available residual capacity of the battery cell is greater than a preset electrical capacity threshold, controlling the direct-current conversion circuit to operate in a constant-voltage working mode, blocking the drive of the discharging tube in the bidirectional DCDC circuit, and driving the charging tube in the bidirectional DCDC circuit to work.

4. The control method of an energy storage system according to claim 1, wherein The battery module comprises a plurality of battery modules, and a power supply end of the battery cell in each battery module is connected with a first end of a corresponding direct-current conversion circuit, and a second end of each direct-current conversion circuit is connected with the direct-current bus of the energy storage converter; If the electrical parameter of the battery cell meets the first preset condition, controlling the direct-current conversion circuit to stabilize the direct-current bus comprises: If the electrical parameter of all battery cells meets the first preset condition, controlling the direct-current conversion circuit to stabilize the direct-current bus.

5. The control method of an energy storage system according to claim 1, wherein The battery module comprises a plurality of battery modules, and a power supply end of the battery cell in each battery module is connected with a first end of a corresponding direct-current conversion circuit, and a second end of each direct-current conversion circuit is connected with the direct-current bus of the energy storage converter; If the electrical parameter of the battery cell meets the first preset condition, controlling the direct-current conversion circuit to stabilize the direct-current bus comprises: If there is a battery cell whose electrical parameter does not meet the first preset condition, controlling the energy storage converter to stabilize the direct-current bus.

6. The control method of an energy storage system according to claim 1, wherein If the electrical parameter of the battery unit does not satisfy the first preset condition, the energy storage converter is controlled to stabilize the DC bus voltage. If the electrical parameter of the battery unit does not satisfy the first preset condition, the energy storage converter is controlled to work in a constant voltage mode, so that the energy storage converter stabilizes the DC bus voltage.

7. The control method of an energy storage system according to claim 1, wherein If the electrical parameter of the battery unit satisfies the first preset condition, the DC conversion circuit is controlled to stabilize the DC bus voltage. If the electrical parameter of the battery unit satisfies the first preset condition and the electricity price of the power grid is lower than a price threshold, the energy storage converter is controlled to stabilize the DC bus voltage. If the electrical parameter of the battery unit satisfies the first preset condition and the electricity price of the power grid is not lower than the price threshold, the DC conversion circuit is controlled to stabilize the DC bus voltage.

8. A controller characterized by comprising: The computer program is executed by the processor to implement the control method of the energy storage system as claimed in any one of claims 1 to 7.

9. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 8. The computer program is executed by the processor to implement the control method of the energy storage system as claimed in any one of claims 1 to 7.

10. An energy storage system characterized by, The control method comprises: The energy storage converter, the battery module and the controller as claimed in claim 8; the battery module comprises a battery unit and a DC conversion circuit; a power supply end of the battery unit is connected with a first end of the DC conversion circuit, and a second end of the DC conversion circuit is connected with a DC bus of the energy storage converter.

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