Energy storage system and control method of energy storage system

Abstract

The invention provides an energy storage system and a control method of the energy storage system, and belongs to the technical field of energy storage control. A first end of an electric energy conversion unit in the energy storage system is connected with a first power supply, a second end and a third end of the electric energy conversion unit are respectively connected with a first end and a second end of a first adjusting unit, a fourth end of the electric energy conversion unit is connected with a first control end of a first control module, and a fifth end of the electric energy conversion unit is connected with a load; the third end of the first adjusting unit is connected with the first end of the energy storage device and the sampling end of the first control module, the fourth end of the first adjusting unit is connected with the second end of the energy storage device, and the fifth end of the first adjusting unit is connected with the second control end of the first control module; the communication end of the first control module is connected with the communication end of the energy storage device. The effect of preventing partial battery units or battery cells in the energy storage device from triggering overvoltage protection in the charging process of the energy storage device to affect normal operation of the whole energy storage system can be achieved.

Description

Technical Field

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

[0002] Common energy storage systems generally include energy storage inverters, photovoltaic modules and battery packs. The energy storage inverter is composed of grid-side inverter circuits, photovoltaic-side BOOST circuits, battery-side BUCK-BOOST circuits and busbars. The battery pack is composed of battery cells, battery management systems and internal bidirectional conversion units as a module. Since the battery packs in the energy storage system often need to be recharged, and the discharge degree and maximum charge of each battery pack may vary to a certain extent, one or more battery packs in the energy storage system may have overcharge problems.

[0003] In the related art, in the common charging overvoltage protection scheme, the related technicians often add a hardware protection circuit between the energy storage converter and the energy storage battery pack, and add a charging cut-off circuit composed of a switch tube and a protection resistor between the energy storage converter and the battery pack. When the charging current limit value is 0, the switch tube is directly turned off to achieve complete charging current cut-off. Alternatively, a software protection strategy is added on the energy storage battery side. When the SOC (State Of Charge) of the battery pack is 100% and the cell single cell voltage reaches the charging limit, the bidirectional conversion unit of the battery pack is turned off to prevent the charging current from continuing to flow to the battery.

[0004] However, adding hardware protection circuits in related technologies requires the introduction of various power switch tubes, protection resistors, capacitors and other devices, which will cause additional energy loss and have the problem of complex control. In addition, the solution of adding software protection strategy will affect the dynamic response performance of the system. Summary of the invention

[0005] The purpose of the present application is to provide an energy storage system and a control method for the energy storage system, which can prevent some battery cells or cells in the energy storage device from triggering overvoltage protection during the charging process of the energy storage device, thereby affecting the normal operation of the entire energy storage system.

[0006] The embodiment of the present application is implemented as follows:

[0007] According to a first aspect of an embodiment of the present application, an energy storage system is provided, the energy storage system comprising at least: an energy storage converter and an energy storage device; the energy storage converter comprises an electric energy conversion unit, a first adjustment unit, and a first control module;

[0008] The first end of the power conversion unit is connected to the first power supply, the second end and the third end of the power conversion unit are connected to the first end and the second end of the first adjustment unit respectively, the fourth end of the power conversion unit is connected to the first control end of the first control module, and the fifth end of the power conversion unit is connected to the load; the power conversion unit is used to perform AC / DC conversion under the control of the first control module, and output the converted electric energy to the first adjustment unit and / or the load;

[0009] The third end of the first adjustment unit is connected to the first end of the energy storage device and the sampling end of the first control module respectively, the fourth end of the first adjustment unit is connected to the second end of the energy storage device, and the fifth end of the first adjustment unit is connected to the second control end of the first control module; the first adjustment unit is used to adjust the charging and discharging power of the energy storage device under the control of the first control module;

[0010] The communication end of the first control module is connected to the communication end of the energy storage device; the first control module is used to obtain the operating parameters of the energy storage device and control the first adjustment unit according to the operating parameters;

[0011] The operating parameters include at least one of the following: the total voltage, the total current, the current limiting parameter, the voltage limiting parameter of the energy storage device, and the branch voltage and branch current of each battery unit in the energy storage device.

[0012] Optionally, the energy storage system further includes a second adjustment unit;

[0013] The first end and the second end of the second adjustment unit are respectively used to connect to a second power source, the third end of the second adjustment unit is respectively connected to the second end of the power conversion unit and the first end of the first adjustment unit, and the fourth end of the second adjustment unit is respectively connected to the third end of the power conversion unit and the second end of the first adjustment unit;

[0014] The second adjustment unit is used for adjusting the electric energy input by the second power supply and outputting the adjusted electric energy to the first adjustment unit.

[0015] Optionally, the first adjustment unit includes: a first switch tube, a second switch tube, and an inductor;

[0016] The first electrode of the first switch tube is connected to the second end of the electric energy conversion unit, the second electrode of the first switch tube is respectively connected to the first end of the inductor and the first electrode of the second switch tube, and the third electrode of the first switch tube is respectively connected to the second electrode of the second switch tube and the second control end of the first control module;

[0017] The third electrode of the second switch tube is respectively connected to the third end of the electric energy conversion unit and the second end of the energy storage device;

[0018] The second end of the inductor is connected to the first end of the energy storage device and the sampling end of the first control module respectively.

[0019] Optionally, the first control module includes a first control subunit, a second control subunit and a third control subunit;

[0020] The control end of the first control subunit is connected to the fourth end of the power conversion unit; the first control subunit is used to control the power conversion unit to perform AC / DC conversion;

[0021] The control end of the second control subunit is connected to the third pole of the first switch tube and the second pole of the second switch tube respectively; the second sub-control module is used to output a control signal for turning on or off the first switch tube and the second switch tube to adjust the charging and discharging power of the energy storage device;

[0022] The first communication end of the third control subunit is connected to the communication end of the energy storage device, the second communication end of the third control subunit is connected to the communication end of the first control subunit, and the third communication end of the third control subunit is connected to the communication end of the second control subunit; the third control subunit is used to realize communication between the first control subunit, the second control subunit and / or the energy storage device.

[0023] Optionally, the energy storage device comprises: a plurality of battery cells and a second control module;

[0024] The first end of each battery unit is connected to the second end of the inductor, the second end of each battery unit is connected to the third pole of the second switch tube, and the communication end of each battery unit is connected to the first communication end of the second control module;

[0025] The second communication terminal of the second control module is connected to the first communication terminal of the third control subunit;

[0026] The second control module is used to determine the operating parameters and send the operating parameters to the third control subunit.

[0027] Optionally, the battery unit comprises: a battery cell group, a third adjustment unit and a battery management system, wherein the battery cell group comprises at least one battery cell;

[0028] The first end and the second end of the third adjustment unit are respectively connected to the second end of the inductor and the third electrode of the second switch tube, the third end and the fourth end of the third adjustment unit are respectively connected to the first end and the second end of the battery cell group, and the fifth end of the third adjustment unit is connected to the first communication end of the second control module; the third adjustment unit is at least used to adjust the charge and discharge state of the battery cell group;

[0029] The first end of the battery management system is connected to the third end of the battery cell group, and the second end of the battery management system is connected to the first communication end of the second control module; the battery management system is used to determine the parameters of the battery cell group and output the parameters of the battery cell group to the second control module.

[0030] Optionally, the energy storage converter further includes: a filter capacitor;

[0031] The filter capacitor is connected between the first end and the second end of the first adjustment unit.

[0032] A second aspect of an embodiment of the present application provides a control method for an energy storage system, the method being applied to any energy storage system described in the first aspect above, wherein an energy storage converter in the energy storage system comprises an electric energy conversion unit, a first adjustment unit, and a control module; the method comprising:

[0033] The first control module obtains operating parameters of the energy storage device in the energy storage system, and determines whether the operating parameters meet a first preset condition;

[0034] If the conditions are met, the first control module determines a first current compensation method, and controls the first adjustment unit to adjust the charge and discharge power of the energy storage device according to the first current compensation method;

[0035] If not, the first control module determines a second current compensation method when determining that the operating parameter meets the second preset condition, and controls the first adjustment unit to adjust the charging and discharging power of the energy storage device according to the second current compensation method.

[0036] Optionally, the first control module obtains operating parameters of the energy storage device in the energy storage system, and determines whether the operating parameters meet a first preset condition, including:

[0037] Obtaining the maximum branch voltage, charging voltage limit value, charging current limit value of each battery unit in the energy storage device and the charge state of the energy storage device;

[0038] Determining whether the highest branch voltage of each of the battery cells is greater than or equal to the charging voltage limit value, and determining whether the state of charge meets a preset threshold;

[0039] If yes, determining that the operating parameter satisfies the first preset condition;

[0040] The first control module determines a first current compensation method, and controls the first adjustment unit to adjust the charge and discharge power of the energy storage device according to the first current compensation method, including:

[0041] Determining a compensation reference value of the first adjustment unit based on the total current of the energy storage device and the compensation variable;

[0042] Using the compensation reference value as a limit loop for the first control module to output a signal to the first adjustment unit, and determining a control reference value based on the compensation reference value and a reference voltage value;

[0043] A control signal is generated according to the control reference value and the charging current limit value, and the control signal is output to the first adjustment unit.

[0044] Optionally, the method further comprises:

[0045] The first control module controls to stop charging the energy storage device;

[0046] The first control module reacquires the highest branch voltage of each battery unit in the energy storage device, and determines whether the highest branch voltage is greater than or equal to the charging voltage limit value;

[0047] If so, it is determined that the operating parameter meets the second preset condition.

[0048] The beneficial effects of the embodiments of the present application include:

[0049] An energy storage system provided by an embodiment of the present application is provided with an energy storage converter and an energy storage device in the energy storage system, and the energy storage converter includes an electric energy conversion unit, a first adjustment unit, and a first control module. Specifically, the first end of the electric energy conversion unit is connected to the first power source, the second end and the third end of the electric energy conversion unit are respectively connected to the first end and the second end of the first adjustment unit, the fourth end of the electric energy conversion unit is connected to the first control end of the first control module, and the fifth end of the electric energy conversion unit is connected to the load. The third end of the first adjustment unit is respectively connected to the first end of the energy storage device and the sampling end of the first control module, the fourth end of the first adjustment unit is connected to the second end of the energy storage device, and the fifth end of the first adjustment unit is connected to the second control end of the first control module. The communication end of the first control module is connected to the communication end of the energy storage device.

[0050] Among them, the first control module can obtain the operating parameters of the energy storage device, such as the total voltage, total current, current limiting parameters, voltage limiting parameters, branch voltage and branch current of each battery cell in the energy storage device, and determine the working conditions of the energy storage device and / or each battery cell in the energy storage device according to the operating parameters, and then determine whether the energy storage device needs to be current compensated. When the energy storage device needs to be current compensated, the first control module can control the first adjustment unit to be turned on or off, and then adjust the output current of the first adjustment unit to change the input current or output current of the energy storage device. In this way, when some battery cells or some battery cells in the energy storage device have completed charging, while some battery cells or some battery cells have not completed charging, the current value output by the energy storage inverter to the energy storage device can be adjusted.

[0051] In this way, it is possible to prevent some battery cells or cells in the energy storage device from triggering overvoltage protection during the charging process of the energy storage device, thereby preventing the normal operation of the entire energy storage system from being affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0053] Figure 1 A schematic diagram of the structure of a first energy storage system provided in an embodiment of the present application;

[0054] Figure 2 A schematic diagram of the structure of a second energy storage system provided in an embodiment of the present application;

[0055] Figure 3 A schematic diagram of the structure of a third energy storage system provided in an embodiment of the present application;

[0056] Figure 4 A schematic diagram of the structure of a fourth energy storage system provided in an embodiment of the present application;

[0057] Figure 5 A flow chart of a control method for a first energy storage system provided in an embodiment of the present application;

[0058] Figure 6 A flow chart of a second method for controlling an energy storage system provided in an embodiment of the present application;

[0059] Figure 7 A block diagram of a compensation control strategy provided in an embodiment of the present application. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0061] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0062] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0063] In the description of the present application, it should be noted that the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0064] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0065] In the related art, in the common charging overvoltage protection scheme, the related technicians often add a hardware protection circuit between the energy storage converter and the energy storage battery pack, and add a charging cut-off circuit composed of a switch tube and a protection resistor between the energy storage converter and the battery pack. When the charging current limit value is 0, the switch tube is directly turned off to achieve complete charging current cut-off. Alternatively, a software protection strategy is added on the energy storage battery side. When the SOC (State Of Charge) of the battery pack is 100% and the cell single cell voltage reaches the charging limit, the bidirectional conversion unit of the battery pack is turned off to prevent the charging current from continuing to flow to the battery.

[0066] However, adding hardware protection circuits in related technologies requires the introduction of various power switch tubes, protection resistors, capacitors and other devices, which will cause additional energy loss and have the problem of complex control. In addition, the solution of adding software protection strategy will affect the dynamic response performance of the system.

[0067] To this end, an embodiment of the present application provides an energy storage system, which includes at least an energy storage converter and an energy storage device. By setting an electric energy conversion unit, a first adjustment unit, and a control module in the energy storage converter, and connecting the first end of the electric energy conversion unit to the first power supply, the second end and the third end of the electric energy conversion unit are respectively connected to the first end and the second end of the first adjustment unit, the fourth end of the electric energy conversion unit is connected to the first control end of the control module, and the fifth end of the electric energy conversion unit is connected to the load; the third end of the first adjustment unit is respectively connected to the first end of the energy storage device and the sampling end of the control module, the fourth end of the first adjustment unit is connected to the second end of the energy storage device, and the fifth end of the first adjustment unit is connected to the second control end of the control module; the communication end of the control module is connected to the communication end of the energy storage device. It can achieve the effect of preventing some battery cells or cells in the energy storage device from triggering overvoltage protection during the charging process of the energy storage device, thereby affecting the normal operation of the entire energy storage system.

[0068] The embodiment of the present application is described by taking the energy storage system applied to charging overvoltage protection as an example, but it does not mean that the energy storage system provided by the embodiment of the present application can only be applied to charging overvoltage protection.

[0069] The energy storage system provided in the embodiment of the present application is explained in detail below.

[0070] Figure 1 This is a schematic diagram of the structure of an energy storage system provided in this application. Figure 1 An embodiment of the present application provides an energy storage system, which includes at least: an energy storage converter 101 and an energy storage device 102 .

[0071] The energy storage converter 101 includes an electric energy conversion unit 1011 , a first adjustment unit 1012 , and a first control module 1013 .

[0072] The first end of the power conversion unit 1011 is connected to the first power supply, the second end and the third end of the power conversion unit 1011 are respectively connected to the first end and the second end of the first adjustment unit 1012, the fourth end of the power conversion unit 1011 is connected to the first control end of the first control module 1013, and the fifth end of the power conversion unit 1011 is connected to the load.

[0073] The third end of the first adjustment unit 1012 is connected to the first end of the energy storage device 102 and the sampling end of the first control module 1013 respectively, the fourth end of the first adjustment unit 1012 is connected to the second end of the energy storage device 102, and the fifth end of the first adjustment unit 1012 is connected to the second control end of the first control module 1013.

[0074] The communication terminal of the first control module 1013 is connected to the communication terminal of the energy storage device 102 .

[0075] The power conversion unit 1011 may be configured to perform AC / DC conversion under the control of the first control module 1013 , and output the converted power to the first adjustment unit 1012 and / or the load F.

[0076] Specifically, the power conversion unit 1011 can be used to receive the first power input by the first power supply 103, and output the first power to the first adjustment unit 1012 and / or the load F. The first power can be alternating current, and when the power conversion unit 1011 outputs the first power, the first power can be converted into alternating current of other voltage levels for output, or the first power can be directly converted into direct current for output.

[0077] The power conversion unit 1011 can also be used to receive the second power input by the energy storage device 102, and output the second power to the load F or the first power supply 103. The second power can be direct current, and when the power conversion unit 1011 outputs the second power, the second power can be converted into direct current of other voltage levels for output, or the second power can be directly converted into alternating current for output.

[0078] The conversion function of the power conversion unit 1011 can be adjusted according to the power demand of the load F and the current charging and discharging state of the energy storage system, which is not limited in this embodiment of the present application.

[0079] In this embodiment, the power conversion unit 1011 may be any possible inverter unit, for example, a bidirectional inverter, which is not limited in this embodiment of the present application.

[0080] Optionally, the first power source 103 may be a mains power network, or any other power source capable of outputting alternating current, which is not limited in the embodiment of the present application.

[0081] Optionally, the first adjustment unit 1012 is used to adjust the charging and discharging power of the energy storage device 102 under the control of the first control module 1013 .

[0082] In addition, the first adjustment unit 1012 may also be used to switch the charging and discharging state of the energy storage device 102 .

[0083] Specifically, the first adjustment unit 1012 may be a BUCK-BOOST circuit, which may switch the charge and discharge state of the energy storage device 102 in any possible manner, or adjust the charge and discharge power of the energy storage device 102 in any possible manner.

[0084] The charging and discharging power includes the charging power when the energy storage converter 101 charges each battery unit in the energy storage device 102 , and the discharging power when the energy storage device 102 discharges to the energy storage converter 101 .

[0085] In one possible manner, the energy storage device 102 may include multiple battery cells, and the multiple battery cells may be connected in series or in parallel according to actual needs, and each battery cell may include at least one battery cell. This embodiment of the application is not limited to this.

[0086] Optionally, the first control module 1013 is used to obtain the operating parameters of the energy storage device 102 and control the first adjustment unit 1012 according to the operating parameters. The first control module 1013 can also be used to control the power conversion unit 1011 so that the power conversion unit 1011 can accurately perform AC / DC conversion and / or control the relay Break to be turned on and off.

[0087] The first control module 1013 and the energy storage device 102 may exchange information via CAN communication, which is not limited in the embodiment of the present application.

[0088] Optionally, the operating parameter includes at least one of the following: a total voltage, a total current, a current limiting parameter of the energy storage device 102 , and a branch voltage and a branch current of each battery unit in the energy storage device 102 .

[0089] Exemplarily, the total voltage may refer to the total voltage (or average voltage) that can be applied to the outside after the battery cells in the energy storage device 102 are connected; the total current may refer to the total current (or average current) that can be output to the outside after the battery cells in the energy storage device 102 are connected; the current limiting parameter may refer to the limiting current value of the energy storage device 102 at the current moment, which may specifically include the maximum output current, the maximum input current, the minimum input current, and the minimum output current; the branch voltage and branch current of the battery cell refer to the voltage and current that each battery cell can output to the outside when the battery cells in the battery cell are taken as a whole.

[0090] For example, if a battery unit has only one cell, the branch voltage and branch current of the battery unit can refer to the single cell voltage and single cell current of the cell itself. For another example, if a battery unit has two or more cells connected in series or in parallel, the branch voltage and branch current of the battery unit can refer to the overall voltage or overall current of these cells after they are connected in series or in parallel.

[0091] For example, if a battery unit has two cells with the same parameters and connected in series, the branch voltage of the battery unit is the sum of the single cell voltages of the two cells, and the branch current of the battery unit is the single cell current of the two cells. In addition, if a battery unit has two cells with the same parameters and connected in parallel, the branch voltage of the battery unit is the single cell voltage of the two cells, and the branch current of the battery unit is the sum of the single cell currents of the two cells.

[0092] In addition, the operating parameters may also include a voltage limit parameter, etc. The voltage limit parameter may refer to a voltage limit value at the current moment. This embodiment of the present application does not limit this.

[0093] In this embodiment, the operating parameter can be specifically used to indicate the specific operating conditions of the energy storage device 102 and / or each battery cell and / or each battery cell in the energy storage device 102 at the current moment, and can also indicate whether each battery cell and / or each battery cell in the energy storage device 102 needs current compensation or overvoltage protection.

[0094] In addition, when the first control module 1013 controls the first adjustment unit 1012 according to the operating parameter, the control can be performed based on the maximum branch voltage among the branch voltages of the battery cells in the energy storage device 102. Further, if each battery cell has only one battery cell, the first control module 1013 can control the first adjustment unit 1012 based on the maximum single cell voltage among the voltages of the battery cells in the energy storage device 102.

[0095] Optionally, the first control module 1013 controlling the first adjustment unit 1012 to adjust the charge and discharge power of the energy storage device 102 may specifically mean that the first control module 1013 outputs a corresponding control signal to the first adjustment unit 1012 to change the current output by the first adjustment unit 1012 (or the current allowed to pass), thereby achieving the purpose of adjusting the current output by the energy storage device 102 or the current input to the energy storage device 102.

[0096] It can be understood that when the energy storage device 102 is charged, the current flows from the first adjustment unit 1012 to the energy storage device 102. At this time, if the current output by the first adjustment unit 1012 is changed, it means changing the charging current of the energy storage device 102. When the energy storage device 102 is discharged, the current flows from the energy storage device 102 to the first adjustment unit 1012. At this time, if the current output by the first adjustment unit 1012 is changed, it means changing the discharge current of the energy storage device 102.

[0097] It is worth noting that after the energy storage system is powered on, the first control module 1013 can first obtain the operating parameters, and further determine whether the operating parameters meet the first preset condition for indicating whether current compensation is required. If so, it can be based on the above. If the first preset condition is not met, it can first control to stop charging the energy storage device 102, and determine whether the operating parameters meet the second preset condition for indicating whether current compensation can be performed. When it is determined that the operating parameters meet the second preset condition, it can be based on the above.

[0098] Among them, the first preset condition and / or the second preset condition can be any possible conditions set by relevant technical personnel. The first preset condition and the second preset condition can be different or the same, and the embodiment of the present application does not limit this.

[0099] Generally, the first control module 1013 is specifically used to compensate according to the discharge current limit value sent by the energy storage device 102 when the energy storage device 102 is discharged when the energy storage device 102 is charged, and this embodiment of the application does not limit this.

[0100] In the embodiment of the present application, an energy storage converter 101 and an energy storage device 102 are provided in the energy storage system, and the energy storage converter 101 includes an electric energy conversion unit 1011, a first adjustment unit 1012, and a first control module 1013. Specifically, the first end of the electric energy conversion unit 1011 is connected to the first power source, the second end and the third end of the electric energy conversion unit 1011 are respectively connected to the first end and the second end of the first adjustment unit 1012, the fourth end of the electric energy conversion unit 1011 is connected to the first control end of the first control module 1013, and the fifth end of the electric energy conversion unit 1011 is connected to the load. The third end of the first adjustment unit 1012 is respectively connected to the first end of the energy storage device 102 and the sampling end of the first control module 1013, the fourth end of the first adjustment unit 1012 is connected to the second end of the energy storage device 102, and the fifth end of the first adjustment unit 1012 is connected to the second control end of the first control module 1013. The communication terminal of the first control module 1013 is connected to the communication terminal of the energy storage device 102 .

[0101] Among them, the first control module 1013 can obtain the total voltage, total current, current limiting parameters, voltage limiting parameters, branch voltage and branch current of each battery unit in the energy storage device 102 and other operating parameters of the energy storage device 102, and determine the working conditions of the energy storage device 102 and / or each battery unit in the energy storage device 102 according to the operating parameters, and then determine whether it is necessary to perform current compensation on the energy storage device 102. When it is necessary to perform current compensation on the energy storage device 102, the first control module 103 can control the first adjustment unit 1012 to be turned on or off, and then adjust the output current of the first adjustment unit 1012 to change the input current or output current of the energy storage device 102. In this way, when some battery units or some battery cells in the energy storage device 102 have completed charging, while some battery units or some battery cells have not completed charging, the current value output by the energy storage converter 101 to the energy storage device 102 can be adjusted.

[0102] In this way, it is possible to prevent some battery cells or cells in the energy storage device 102 from triggering overvoltage protection during the charging process of the energy storage device 102, thereby preventing the normal operation of the entire energy storage system from being affected.

[0103] Furthermore, when the energy storage device 102 is charged, it is also possible to ensure that the current compensation can be controlled according to the current limiting value indicated by the energy storage device 102, thereby improving the current compensation effect of the energy storage system.

[0104] For a possible implementation, see Figure 2 , the energy storage system also includes a second adjustment unit 104.

[0105] The first end and the second end of the second adjustment unit 104 are respectively used to connect to the second power supply 105, the third end of the second adjustment unit 104 is respectively connected to the second end of the power conversion unit 1011 and the first end of the first adjustment unit 1012, and the fourth end of the second adjustment unit 104 is respectively connected to the third end of the power conversion unit 1011 and the second end of the first adjustment unit 1012.

[0106] Optionally, the second power source 105 may be any power source that can output direct current power. For example, the second power source 105 may be a photovoltaic power generation component, which is not limited in the embodiment of the present application.

[0107] In this embodiment, the second adjustment unit 104 is used to adjust the electric energy input by the second power source 105 , and output the adjusted electric energy to the first adjustment unit 1012 .

[0108] In addition, the second adjustment unit 104 can also be used to output the adjusted electric energy to the electric energy conversion circuit 1011, and then output it to the load F and / or the first power supply 103 through the electric energy conversion circuit 1011, and the second adjustment unit 104 can be controlled by the first control module, so as to achieve efficient management and optimization of the energy provided by the first power supply 103, the second power supply 105, and the energy storage device 102. This embodiment of the application is not limited to this.

[0109] Optionally, the second adjustment unit 104 may be a BOOST circuit, which may be specifically used for voltage boosting.

[0110] Specifically, the second adjustment unit 104 can perform a voltage-boosting process on the electric energy input from the second power source 105 , so that the electric energy input from the second power source 105 can be normally incorporated into the energy storage converter 101 .

[0111] In this way, the purpose of storing electrical energy input from multiple different power sources can be achieved.

[0112] For a possible implementation, see Figure 2 The first adjustment unit 1012 includes: a first switch tube Q1, a second switch tube Q2, and an inductor L.

[0113] The first pole of the first switch tube Q1 is connected to the second end of the power conversion unit 1011, the second pole of the first switch tube Q1 is respectively connected to the first end of the inductor L and the first pole of the second switch tube Q2, and the third pole of the first switch tube Q1 is respectively connected to the second pole of the second switch tube Q2 and the second control end of the first control module 1013.

[0114] The third electrode of the second switch tube Q2 is connected to the third end of the power conversion unit 1011 and the second end of the energy storage device 102 respectively.

[0115] The second end of the inductor L is connected to the first end of the energy storage device 102 and the sampling end of the first control module 1013 respectively.

[0116] Optionally, the first switch tube Q1 and the second switch tube Q2 may be any possible controllable switch tubes such as triodes, MOS tubes, IGBTs, etc. For example, the first switch tube Q1 may be an NMOS tube, and the second switch tube Q2 may also be an NMOS tube, which is not limited in the present embodiment.

[0117] Optionally, the inductor L may be any possible inductor, and the parameters of the inductor L may be selected according to actual needs of the energy storage system.

[0118] In this embodiment, the inductor L can be used as an energy storage and discharge element. For example, it can be discharged when the first switch tube Q1 and / or the second switch tube Q2 is turned on, and charged when the first switch tube Q1 and / or the second switch tube Q2 is turned off. This embodiment of the present application is not limited to this.

[0119] Specifically, the first switch tube Q1 and the second switch tube Q2 can be used to adjust the output current of the first adjustment unit 1012 in the first switch tube Q1 and the second switch tube Q2.

[0120] It is understandable that, in this way, the first control module 1013 can control the first switch tube Q1 and the second switch tube Q2 to be alternately turned on and off, so as to achieve the purpose of current compensation for the energy storage device 102 .

[0121] For a possible implementation, see Figure 3 The first control module 1013 includes a first control subunit INV, a second control subunit DC and a third control subunit EMS.

[0122] The control end of the first control subunit INV is connected to the fourth end of the power conversion unit 1011 .

[0123] The control end of the second control subunit DC is connected to the third electrode of the first switch tube Q1 and the second electrode of the second switch tube Q2 respectively.

[0124] The first communication terminal of the third control subunit EMS is connected to the communication terminal of the energy storage device 102 , the second communication terminal of the third control subunit EMS is connected to the communication terminal of the first control subunit INV, and the third communication terminal of the third control subunit EMS is connected to the communication terminal of the second control subunit DC.

[0125] Optionally, the first control subunit INV is used to control the power conversion unit 1011 to perform AC-DC conversion. In addition, the first control subunit INV can also be used to detect the grid-connected relay Break and control the grid-connected relay Break to achieve grid-connected and off-grid switching of the energy storage converter 101.

[0126] Optionally, the second control subunit DC is used to output a control signal for turning on or off the first switch tube Q1 and the second switch tube Q2 to adjust the charging and discharging power of the energy storage device 102 .

[0127] In addition, when the energy storage system includes a second adjustment unit 104, the second control subunit DC can also be used to control the second adjustment unit 104 to boost the voltage to match the voltage of the bus BUS (that is, the connecting line between the power conversion unit 1011 and the first adjustment unit 1012), so that the voltage input by the second power supply 105 can be smoothly incorporated into the energy storage inverter 101.

[0128] Optionally, the third control subunit EMS is used to implement communication between the first control subunit INV, the second control subunit DC and / or the energy storage device 102 .

[0129] The third control subunit EMS can be specifically used to send the operating parameters of the energy storage device 102 to the first control subunit INV and the second control subunit DC, or control the first control subunit INV and the second control subunit DC to act based on the operating parameters. This embodiment of the application does not limit this.

[0130] In this way, different subunits can be used to control each component in the energy storage converter 101 to reduce the processing pressure of each subunit, avoid using one controller to control each component, resulting in complex logic or downtime, and thus improve the stability of the energy storage system.

[0131] For a possible implementation, see Figure 3 The energy storage device 102 includes: a plurality of battery cells 1021 and a second control module 1022 .

[0132] The first end of each battery unit 1021 is connected to the second end of the inductor L, the second end of each battery unit 1021 is connected to the third pole of the second switch tube Q2, and the communication end of each battery unit 1021 is connected to the first communication end of the second control module 1022.

[0133] The second communication terminal of the second control module 1022 is connected to the first communication terminal of the third control subunit EMS.

[0134] The second control module 1022 is used to determine the operating parameters and send the operating parameters to the third control subunit EMS.

[0135] Optionally, the second control module 1022 may be a control board disposed in a control box of the energy storage device 102 and having functions of processing, identification, calculation, communication, etc.

[0136] For example, the second control module 1022 can be used to obtain the voltage and current of each battery cell 1021, and then add and sum the voltage and current of each battery cell 1021 to obtain the total voltage and total current of the energy storage device 102. It can also be used to compare the voltage and / or current of each battery cell 1021, and determine the maximum voltage and / or maximum current in each battery cell 1021. It can also be used to obtain the limiting current value of each battery cell 1021, and output the limiting current value, the total voltage, the total current, the maximum voltage and / or the maximum current, and any other possible parameters to the third control subunit EMS. This embodiment of the present application is not limited to this.

[0137] In this way, the energy storage converter 101 can accurately know the operating conditions and operating parameters of each battery unit 1021 in the energy storage device 102 , so that the energy storage converter 101 can better perform current compensation or overvoltage protection on the energy storage device 102 .

[0138] For a possible implementation, see Figure 4 The battery unit 1021 includes: a battery cell group, a third adjustment unit and a battery management system.

[0139] The first end and the second end of the third adjustment unit are respectively connected to the second end of the inductor L and the third pole of the second switch tube Q2, the third end and the fourth end of the third adjustment unit are respectively connected to the first end and the second end of the battery cell group, and the fifth end of the third adjustment unit is connected to the first communication end of the second control module 1022.

[0140] The first end of the battery management system is connected to the third end of the battery cell group, and the second end of the battery management system is connected to the first communication end of the second control module 1022 .

[0141] Optionally, the battery cell group may include at least one battery cell, and the battery cells in the battery cell group may be connected in series or in parallel. The battery cell may be any type of energy storage device, such as a lithium battery cell, etc. This embodiment of the application does not limit this.

[0142] The third adjustment unit is at least used to adjust the charge and discharge state of the battery cell group.

[0143] Optionally, the third adjustment unit may be a bidirectional direct current converter (BDC). The BDC can realize the charge and discharge switching of the battery pack by stepping up and down, and limit the charge and discharge power of the energy storage converter 101 to the battery pack by limiting the charge and discharge current.

[0144] Exemplarily, when the battery cell group needs to output a forward voltage (that is, the battery cell discharges), the BDC can output direct current power from the battery cell group to the energy storage inverter 101. In this case, the battery cell group acts as an energy storage unit, and the BDC adjusts the direction and magnitude of the current to ensure the voltage and power output required by the energy storage inverter 101. When the battery cell group needs to output a reverse voltage (that is, the battery cell charges), the BDC can change the direction of the current flow so that the electric energy flows from the energy storage inverter 101 into the battery cell group for charging. This function can be implemented based on the BDC's own structure, or it can be implemented by controlling the BDC with any other possible device, and the embodiments of the present application are not limited to this.

[0145] Specifically, the third adjustment units in each battery unit 1021 can exchange information through CAN communication, and any third adjustment unit can also interact with the second control module 1022 through CAN communication.

[0146] Optionally, the battery management system is used to determine the parameters of the battery cell group and output the parameters of the battery cell group to the second control module 1022 .

[0147] Optionally, the battery management system may be a BMS. The parameters of the battery cell group may include the voltage of the battery cell group, the output current or input current of the battery cell group, and may also include any possible parameters such as a limiting current value or a limiting voltage value of the battery cell group.

[0148] It is understandable that if the battery cell group includes only one battery cell, then the parameters of the battery cell group can be the single cell voltage, single cell output current or single cell input current of this single battery cell. If the battery cell group includes two or more battery cells, then the parameters of the battery cell group can be the voltage, output current or input current of these battery cells as a whole after being connected in series or in parallel, which is specifically determined based on the connection relationship of each battery cell, and the embodiments of the present application do not limit this.

[0149] It is worth noting that the battery management system can accurately know the parameters of each battery cell group in each battery unit 1021, and each battery management system can send the parameters of each battery cell group to the second control module 1022 respectively, so that the second control module 1022 can summarize the parameters of each battery cell group to obtain the above-mentioned operating parameters. In addition, the BDC can also be used to control each battery cell group to switch between the charging state and the discharging state. In this way, the overvoltage protection of the energy storage device 102 can be achieved in conjunction with the output of the energy storage inverter 101.

[0150] For a possible implementation, see Figure 1-4 The energy storage converter 101 also includes: a filter capacitor C0.

[0151] The filter capacitor C0 is connected between the first terminal and the second terminal of the first adjustment unit 1012 .

[0152] Optionally, the filter capacitor C0 may be any possible capacitor, such as an electrolytic capacitor, which is not limited in the embodiment of the present application.

[0153] In this way, the stability of the energy storage converter 101 and / or the energy storage system can be improved based on the voltage stabilization and filtering functions of the filter capacitor C0.

[0154] The following describes the control method of the energy storage system used to control the energy storage system provided in the present application to achieve corresponding functions and effects. The specific implementation process and technical effects are described above and will not be repeated below.

[0155] Figure 5 is a flow chart of a control method of an energy storage system provided in an embodiment of the present application, see Figure 5 , the method comprising:

[0156] Step 2001: The first control module obtains operating parameters of the energy storage device in the energy storage system, and determines whether the operating parameters meet a first preset condition.

[0157] Optionally, the first control module may refer to the above-mentioned first control module 1013 , and the energy storage device may refer to the above-mentioned energy storage device 102 .

[0158] The operating parameters may include: the total voltage, total current, current limiting parameter, voltage limiting parameter, branch voltage of each battery cell and / or branch current of each battery cell of the energy storage device 102. The specific definition of the operating parameters can refer to the description of the above embodiment, and the embodiment of the present application will not be repeated here.

[0159] In this embodiment, the first preset condition may be set according to actual needs and is a condition for determining whether charging current compensation is required.

[0160] Generally, if the operating parameter satisfies the first preset condition, it can be determined that the energy storage device as a whole has been fully charged, and then it can be determined that the charging current can be compensated. If the operating parameter does not meet the first preset condition, it can be determined that the energy storage device as a whole has not been fully charged, but some battery cells have been fully charged, and then it is determined that the charging current is not compensated at present and further judgment is required.

[0161] Step 2002: If satisfied, the first control module determines a first current compensation method, and controls the first adjustment unit to adjust the charge and discharge power of the energy storage device according to the first current compensation method.

[0162] Optionally, the first adjustment unit may be the first adjustment unit 1012 mentioned above.

[0163] Optionally, the first current compensation method may be based on the first current compensation method described above.

[0164] Adjusting the charge and discharge power of the energy storage device can be specifically achieved by adjusting the charging current or the discharging current of the energy storage device.

[0165] Step 2003: If not, the first control module determines a second current compensation method when determining that the operating parameter meets the second preset condition, and controls the first adjustment unit to adjust the charge and discharge power of the energy storage device according to the second current compensation method.

[0166] Optionally, the second preset condition can be set according to actual needs, and is used to re-determine whether charging current compensation is required when the first preset condition is not met and charging is stopped. The second preset condition can be the same as the first preset condition, or different from the first preset condition.

[0167] Generally speaking, if the operating parameters meet the second preset condition, it can be determined that when charging the energy storage device is stopped, the voltage of some battery cells of the energy storage device is still greater than the voltage limit parameter. In this case, it can be determined that the energy storage device as a whole has not been fully charged, but some battery cells are over-voltage, and it can be determined that charging current compensation is currently required.

[0168] If the operating parameter does not satisfy the second preset condition, it is determined that no charging current compensation is currently required.

[0169] Optionally, the second current compensation method is also based on the above-mentioned second current compensation method. In this way, when some battery cells or some battery cells in the energy storage device 102 have completed charging, while some battery cells or some battery cells have not completed charging, the current value output by the energy storage inverter 101 to the energy storage device 102 can be adjusted.

[0170] For a possible implementation, see Figure 6 , the first control module obtains the operating parameters of the energy storage device in the energy storage system, and determines whether the operating parameters meet the first preset condition, including:

[0171] Step 2004: Obtain the highest branch voltage, charging voltage limit value, charging current limit value of each battery unit in the energy storage device and the charge state of the energy storage device.

[0172] Optionally, the charging voltage limit value may refer to the above-mentioned voltage limit parameter, and specifically may refer to the charging cell voltage limit value of each battery cell in the energy storage device. The charging current limit value may refer to the above-mentioned current limit parameter.

[0173] Step 2005: Determine whether the highest branch voltage of each battery unit is greater than or equal to the charging voltage limit value, and determine whether the charge state meets a preset threshold.

[0174] Optionally, the preset threshold may be set according to actual needs, such as setting the preset threshold to 100%, or a certain margin may be appropriately reserved, such as setting the preset threshold to 90%, 95% or any other possible value.

[0175] Step 2006: If yes, determine that the operating parameter meets the first preset condition.

[0176] It is worth noting that if the highest branch of each battery unit (if each battery unit includes only one battery cell, then it is the highest single cell voltage of each battery cell) is greater than or equal to the charging voltage limit value, it can be indicated that some battery units or some batteries in the energy storage device are already fully charged at the current moment. At the same time, if the state of charge meets the preset threshold, it can be indicated that the energy storage device is also fully charged at the current moment. At this time, current compensation or overvoltage protection is required.

[0177] If the highest branch of each battery unit (if each battery unit includes only one battery cell, then the highest single cell voltage of each battery cell) is less than the charging voltage limit value, it can be indicated that all battery units or all batteries in the energy storage device are not fully charged at the current moment. At this time, no current compensation or overvoltage protection is required.

[0178] If the highest branch of each battery unit (if each battery unit includes only one battery cell, then the highest single cell voltage of each battery cell) is greater than or equal to the charging voltage limit value, but the charge state does not meet the preset threshold, it can be indicated that the energy storage device is not fully charged at the current moment. Further judgment is required at this time.

[0179] For example, assuming that the preset threshold is 100%, the highest branch voltage of each battery cell (if each battery cell includes only one battery cell, then the highest single cell voltage of each battery cell) can be recorded as V c_max , the charging voltage limit is recorded as V c_lim , the charging current limit value is recorded as I char_lim And the state of charge of the energy storage device is recorded as the total SOC.

[0180] First, determine V c_max Is it greater than or equal to V c_lim , if V c_max Still less than V c_lim , the charging current compensation strategy is not executed. c_max Greater than or equal to V c_lim , then continue to determine whether the total SOC reaches 100%.

[0181] If the total SOC is 100%, it can be determined that the operating parameter meets the first preset condition and the charging current compensation strategy needs to be executed.

[0182] For a possible implementation, see Figure 6 , the first control module determines a first current compensation method, and controls the first adjustment unit to adjust the charge and discharge power of the energy storage device according to the first current compensation method, including:

[0183] Step 2007: Determine a compensation reference value of the first adjustment unit based on the total current of the energy storage device and the compensation variable.

[0184] Optionally, the total current indicates the total current of each battery cell in the energy storage device as a whole. The compensation variable can be dynamic, for example, the compensation variable can change according to the total battery current, for example, if the total current of the energy storage device sampled is 1A, then the compensation variable is -1A, so that the current reference value after compensation can be ensured to be 0.

[0185] Optionally, the compensation reference value may be used as a current reference value Ir of a control loop used by the first control module to control the first adjustment unit (BUCK-BOOST circuit).

[0186] Step 2008: The compensation reference value is used as a limit loop for the first control module to output a signal to the first adjustment unit, and a control reference value is determined based on the compensation reference value and a reference voltage value. Optionally, the reference voltage value may refer to a reference voltage V of a voltage loop input into a control loop of the first control module. o_ref In this way, the voltage loop output voltage V o Stablize.

[0187] It is worth noting that using the compensation reference value as a limiting loop for the signal output by the first control module to the first adjustment unit may specifically mean using the compensation reference value as a limiting loop to perform upper and lower limit processing on the output of the voltage loop in the control loop of the first control module to obtain the final loop control reference value, that is, the control reference value.

[0188] Step 2009: Generate a control signal according to the control reference value and the charging current limit value, and output the control signal to the first adjustment unit.

[0189] Optionally, the control reference value and the charging current limit value may be input into a current loop in the control loop of the first control module. In this way, the current loop may limit the output signal of the voltage loop according to the charging current limit value Ir, so as to ensure that the first control module and / or the closed-loop control loop can control the current of the energy storage device according to the charging current limit value.

[0190] The control signal may be a PWM signal.

[0191] For example, see Figure 7 , Figure 7 A block diagram showing a possible compensation control strategy is shown, Figure 7 The compensation control strategy in can be

[0192] In a possible implementation, the method further includes:

[0193] The first control module controls to stop charging the energy storage device.

[0194] The first control module reacquires the highest branch voltage of each battery unit in the energy storage device, and determines whether the highest branch voltage is greater than or equal to the charging voltage limit value.

[0195] It is worth noting that since the parallel energy storage system is composed of multiple battery cells in parallel, the SOC of each battery cell will be different due to the differences in the cells and control methods in the battery cells. When a battery cell is fully charged and the SOC is 100%, and other battery cells are not fully charged, the total SOC of the entire energy storage device is not 100%, and the energy storage device will continue to charge. In this way, the battery cells or cells that are fully charged first are prone to overvoltage, so it is necessary to judge again to prevent the problem of single cell overvoltage when the total SOC is not 100%. The safety and applicability of this method can be improved.

[0196] If so, it is determined that the operating parameter meets the second preset condition.

[0197] In this way, when it is determined that the operating parameter meets the second preset condition, the parameters in the energy storage system, for example, the operating parameters at the current moment, can be determined by the above Figure 7 The compensation control strategy shown re-determines the second current compensation mode and executes subsequent steps.

[0198] That is to say, both the first current compensation method and the second current compensation method can be based on the above Figure 7 The parameters of the energy storage system may be different when the first current compensation mode and the second current compensation mode are shown, so the first current compensation mode and the second current compensation mode may also be different.

[0199] It can be understood that the steps provided in this embodiment can be performed when executing the above step 2003, specifically when the first control module determines that the operating parameter meets the second preset condition.

[0200] In one possible manner, when executing the current compensation strategy, since the operating parameters of the energy storage device are constantly changing, the third control subunit EMS can continue to detect the operating parameters in real time until the third control subunit EMS determines that the highest branch voltage of each battery cell in the energy storage device (if the battery cell includes only one battery cell, then it is the highest single cell voltage of this battery cell) has continued to rise for a period of time and no longer continues to rise, that is, the highest branch voltage (or highest single cell voltage) Vc0_max at the previous moment minus the highest branch voltage (or highest single cell voltage) Vc_1max at the current moment stops changing when it is greater than or equal to 0 (and lasts for a certain period of time, such as 5s), and current compensation is exited at this time.

[0201] Alternatively, the previous maximum branch voltage (or maximum single cell voltage) Vc0_max and the current maximum branch voltage (or maximum single cell voltage) Vc_1max can be compared with a preset value respectively. If Vc0_max is continuously detected to be greater than or less than this value for a period of time, current compensation can be exited. Exit current compensation.

[0202] It should be understood that since the method and any of the energy storage systems provided above belong to the same inventive concept, the method may also include any other possible steps to achieve the functions and effects that any of the energy storage systems above can achieve. Similarly, the energy storage system may also include any other possible components to perform any of the steps in the method. This embodiment of the present application will not be elaborated on this.

[0203] The above method is used to control the energy storage system provided by the aforementioned embodiment to achieve corresponding functions. The implementation principles and technical effects of the two are similar and will not be repeated here.

[0204] An embodiment of the present application further provides a computer device, which includes: a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the computer program, the steps in any of the above-mentioned method embodiments are implemented.

[0205] An embodiment of the present application further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented.

[0206] Optionally, the present application also provides a program product, such as a computer-readable storage medium, including a program, which is used to execute any of the above-mentioned energy storage system control method embodiments when executed by a processor.

[0207] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (English: processor) to perform some steps of the methods of various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (English: Read-Only Memory, abbreviated: ROM), random access memory (English: Random Access Memory, abbreviated: RAM), disk or optical disk and other media that can store program codes.

[0208] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0209] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An energy storage system, characterized in that: The energy storage system at least includes: an energy storage converter and an energy storage device; the energy storage converter includes an electric energy conversion unit, a first adjustment unit, and a first control module; The first end of the power conversion unit is connected to the first power supply, the second end and the third end of the power conversion unit are connected to the first end and the second end of the first adjustment unit respectively, the fourth end of the power conversion unit is connected to the first control end of the first control module, and the fifth end of the power conversion unit is connected to the load; the power conversion unit is used to perform AC / DC conversion under the control of the first control module, and output the converted electric energy to the first adjustment unit and / or the load; The third end of the first adjustment unit is connected to the first end of the energy storage device and the sampling end of the first control module respectively, the fourth end of the first adjustment unit is connected to the second end of the energy storage device, and the fifth end of the first adjustment unit is connected to the second control end of the first control module; the first adjustment unit is used to adjust the charging and discharging power of the energy storage device under the control of the first control module; The communication end of the first control module is connected to the communication end of the energy storage device; the first control module is used to obtain the operating parameters of the energy storage device and control the first adjustment unit according to the operating parameters; The operating parameters include at least one of the following: the total voltage, the total current, the current limiting parameter, the voltage limiting parameter of the energy storage device, and the branch voltage and branch current of each battery unit in the energy storage device.

2. The energy storage system of claim 1, wherein: The energy storage system further includes a second adjustment unit; The first end and the second end of the second adjustment unit are respectively used to connect to a second power source, the third end of the second adjustment unit is respectively connected to the second end of the power conversion unit and the first end of the first adjustment unit, and the fourth end of the second adjustment unit is respectively connected to the third end of the power conversion unit and the second end of the first adjustment unit; The second adjustment unit is used for adjusting the electric energy input by the second power supply, and outputting the adjusted electric energy to the first adjustment unit.

3. The energy storage system of claim 1, wherein: The first adjustment unit includes: a first switch tube, a second switch tube, and an inductor; The first electrode of the first switch tube is connected to the second end of the electric energy conversion unit, the second electrode of the first switch tube is respectively connected to the first end of the inductor and the first electrode of the second switch tube, and the third electrode of the first switch tube is respectively connected to the second electrode of the second switch tube and the second control end of the first control module; The third electrode of the second switch tube is respectively connected to the third end of the electric energy conversion unit and the second end of the energy storage device; The second end of the inductor is connected to the first end of the energy storage device and the sampling end of the first control module respectively.

4. The energy storage system according to claim 3, characterized in that: The first control module includes a first control subunit, a second control subunit and a third control subunit; The control end of the first control subunit is connected to the fourth end of the power conversion unit; the first control subunit is used to control the power conversion unit to perform AC / DC conversion; The control end of the second control subunit is connected to the third pole of the first switch tube and the second pole of the second switch tube respectively; the second sub-control module is used to output a control signal for turning on or off the first switch tube and the second switch tube to adjust the charging and discharging power of the energy storage device; The first communication end of the third control subunit is connected to the communication end of the energy storage device, the second communication end of the third control subunit is connected to the communication end of the first control subunit, and the third communication end of the third control subunit is connected to the communication end of the second control subunit; the third control subunit is used to realize communication between the first control subunit, the second control subunit and / or the energy storage device.

5. The energy storage system according to claim 4, characterized in that: The energy storage device comprises: a plurality of battery cells and a second control module; The first end of each battery unit is connected to the second end of the inductor, the second end of each battery unit is connected to the third pole of the second switch tube, and the communication end of each battery unit is connected to the first communication end of the second control module; The second communication terminal of the second control module is connected to the first communication terminal of the third control subunit; The second control module is used to determine the operating parameters and send the operating parameters to the third control subunit.

6. The energy storage system according to claim 5, characterized in that: The battery unit comprises: a battery cell group, a third adjustment unit and a battery management system, wherein the battery cell group comprises at least one battery cell; The first end and the second end of the third adjustment unit are respectively connected to the second end of the inductor and the third electrode of the second switch tube, the third end and the fourth end of the third adjustment unit are respectively connected to the first end and the second end of the battery cell group, and the fifth end of the third adjustment unit is connected to the first communication end of the second control module; the third adjustment unit is at least used to adjust the charge and discharge state of the battery cell group; The first end of the battery management system is connected to the third end of the battery cell group, and the second end of the battery management system is connected to the first communication end of the second control module; the battery management system is used to determine the parameters of the battery cell group and output the parameters of the battery cell group to the second control module.

7. The energy storage system according to any one of claims 1 to 6, characterized in that: The energy storage converter also includes: a filter capacitor; The filter capacitor is connected between the first end and the second end of the first adjustment unit.

8. A control method for an energy storage system, characterized in that: The method is applied to the energy storage system according to any one of claims 1 to 7 above, wherein the energy storage converter in the energy storage system comprises an electric energy conversion unit, a first adjustment unit, and a control module; the method comprises: The first control module obtains operating parameters of the energy storage device in the energy storage system, and determines whether the operating parameters meet a first preset condition; If the conditions are met, the first control module determines a first current compensation method, and controls the first adjustment unit to adjust the charge and discharge power of the energy storage device according to the first current compensation method; If not, the first control module determines a second current compensation method when determining that the operating parameter meets the second preset condition, and controls the first adjustment unit to adjust the charging and discharging power of the energy storage device according to the second current compensation method.

9. The control method of the energy storage system according to claim 8, characterized in that: The first control module obtains operating parameters of the energy storage device in the energy storage system, and determines whether the operating parameters meet a first preset condition, including: Obtaining the maximum branch voltage, charging voltage limit value, charging current limit value of each battery unit in the energy storage device and the charge state of the energy storage device; Determining whether the highest branch voltage of each of the battery cells is greater than or equal to the charging voltage limit value, and determining whether the state of charge meets a preset threshold; If yes, determining that the operating parameter satisfies the first preset condition; The first control module determines a first current compensation method, and controls the first adjustment unit to adjust the charge and discharge power of the energy storage device according to the first current compensation method, including: Determining a compensation reference value of the first adjustment unit based on the total current of the energy storage device and the compensation variable; Using the compensation reference value as a limit loop for the first control module to output a signal to the first adjustment unit, and determining a control reference value based on the compensation reference value and a reference voltage value; A control signal is generated according to the control reference value and the charging current limit value, and the control signal is output to the first adjustment unit.

10. The control method of the energy storage system according to claim 8, characterized in that: The method further comprises: The first control module controls to stop charging the energy storage device; The first control module reacquires the highest branch voltage of each battery unit in the energy storage device, and determines whether the highest branch voltage is greater than or equal to the charging voltage limit value; If so, it is determined that the operating parameter meets the second preset condition.

Images