Energy storage system

Abstract

The utility model provides an energy storage system, the energy storage system comprises three single-phase bridge arms, the structures of the single-phase bridge arms are different, each single-phase bridge arm comprises a plurality of energy storage units connected in series and a filter circuit, the filter circuit is arranged between the AC side of each single-phase bridge arm and the plurality of energy storage units, the structure of each single-phase bridge arm has at least one of the following differences: the number of the plurality of energy storage units is different; and the structures of the plurality of energy storage units are different.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage systems, and in particular to an energy storage system. Background Art

[0002] In traditional energy storage systems, batteries are rigidly connected together in series or parallel. As the system runs for a long time, the inconsistency between batteries continues to expand, causing serious problems such as the wooden barrel effect, circulation between parallel batteries, and failure to disconnect faulty cells in time. These problems seriously affect the healthy operation of the system, shorten the system life, etc., resulting in the safety and economy of the energy storage system being less than expected.

[0003] In order to solve the inconsistency problem of batteries in energy storage systems, complex battery management algorithms are often used, but with little effect despite huge investments. Batteries in energy storage systems still have problems such as "not fully charged, not fully discharged, not accurately measured, and not disconnected".

[0004] In the prior art, the structures of the three-phase bridge arms of the energy storage system are the same. If each single-phase bridge arm uses the same number of energy storage units, when the energy storage unit is damaged, the three phases of the energy storage system will be unbalanced and the capacity will decrease. If the structures of the energy storage units in each single-phase bridge arm are the same, the initial cost will be high. In addition, for some specific power application scenarios, the three-phase bridge arms with the same structure cannot meet the requirements. Utility Model Content

[0005] In view of this, the purpose of the present application is to provide an energy storage system, which can construct single-phase bridge arms with different structures in the energy storage system by changing the number of multiple energy storage units and / or the structure of the energy storage units in each single-phase bridge arm, and set a filtering circuit in each single-phase bridge arm to filter the electric energy flowing through the single-phase bridge arm, thereby solving the technical problems of possible three-phase imbalance, reduced capacity and high cost in the energy storage system in the prior art, and achieving the technical effect of preventing three-phase imbalance, increasing capacity and reducing cost.

[0006] In a first aspect, an embodiment of the present application provides an energy storage system, which includes three single-phase bridge arms, each of which has a different structure. Each single-phase bridge arm includes a plurality of energy storage units and a filter circuit connected in series, and the filter circuit is arranged between the AC side of each single-phase bridge arm and the plurality of energy storage units, wherein the structure of each single-phase bridge arm has at least one of the following differences: the number of the plurality of energy storage units is different; the structure of the plurality of energy storage units is different.

[0007] Optionally, each single-phase bridge arm also includes a single-pole multi-throw switch and a control module, the single-pole multi-throw switch includes multiple branches, and for each branch, the branch is a clear branch, connected to the filter circuit, or connected to the protection circuit, wherein the control module is configured to: control the clear branch of the single-pole multi-throw switch to connect to the single-phase bridge arm, control the branch of the single-pole multi-throw switch connected to the filter circuit to connect to the single-phase bridge arm, or control the branch of the single-pole multi-throw switch connected to the protection circuit to connect to the single-phase bridge arm.

[0008] Optionally, each energy storage unit includes a bridge circuit, wherein the structure of the energy storage unit is changed by setting different bridge circuits, wherein, for each single-phase bridge arm, the bridge circuit of multiple energy storage units corresponding to the single-phase bridge arm is a full-bridge circuit and / or a half-bridge circuit.

[0009] Optionally, each energy storage unit also includes a battery pack, which includes at least one battery, and the battery pack is connected to the DC side of the bridge circuit corresponding to each energy storage unit, and the energy storage units corresponding to each single-phase bridge arm are connected in series in sequence through the AC side of the bridge circuit.

[0010] Optionally, for each single-phase bridge arm, when the bridge circuits of the multiple energy storage units corresponding to the single-phase bridge arm are not all full-bridge circuits, the single-phase bridge arm also includes a level control circuit, and the level control circuit is arranged between the input and output interface of the single-phase bridge arm and the multiple energy storage units of the single-phase bridge arm.

[0011] Optionally, the DC side of the bridge circuit includes a first DC connection terminal and a second DC connection terminal, and the AC side of the bridge circuit includes a first AC connection terminal and a second AC connection terminal. For each energy storage unit of each single-phase bridge arm, the first DC connection terminal and the second DC connection terminal of the energy storage unit are connected to the battery pack, and the first AC connection terminal of the energy storage unit is connected to the second AC connection terminal of the next energy storage unit.

[0012] Optionally, the level control circuit is configured as a full-bridge circuit, and for each single-phase bridge arm, the first DC connection end of the level control circuit of the single-phase bridge arm is connected to the first AC connection end of the first energy storage unit among the multiple energy storage units connected in series, the second DC connection end of the level control circuit is connected to the second AC connection end of the last energy storage unit among the multiple energy storage units connected in series, and the AC side of the level control circuit is connected to the input and output ends of the single-phase bridge arm.

[0013] Optionally, the full-bridge circuit includes a first control switch, a second control switch, a third control switch and a fourth control switch, wherein the first connection end of the first control switch is connected to the first connection end of the second control switch, the second connection end of the first control switch is connected to the first connection end of the third control switch, the second connection end of the third control switch is connected to the second connection end of the fourth control switch, and the second connection end of the second control switch is connected to the first connection end of the fourth control switch, wherein the connection between the first control switch and the second control switch serves as the first DC connection end of the full-bridge circuit, the connection between the third control switch and the fourth control switch serves as the second DC connection end of the full-bridge circuit, the connection between the first control switch and the third control switch serves as the first AC connection end of the full-bridge circuit, and the connection between the second control switch and the fourth control switch serves as the second AC connection end of the full-bridge circuit.

[0014] Optionally, the half-bridge circuit includes a fifth control switch and a sixth control switch, the first connection end of the fifth control switch serves as the first DC connection end of the half-bridge circuit, the second connection end of the fifth control switch is connected to the first connection end of the sixth control switch, the second connection end of the sixth control switch serves as the second DC connection end of the half-bridge circuit, the connection between the fifth control switch and the sixth control switch serves as the first AC connection end of the half-bridge circuit, and the connection between the sixth control switch and the battery serves as the second AC connection end of the half-bridge circuit.

[0015] Optionally, the energy storage system further includes a three-phase electrical switch and a three-phase electrical protection circuit, wherein the three-phase electrical switch is used to change the on-off state of each single-phase bridge arm, and the three-phase electrical protection circuit is respectively connected to each single-phase bridge arm.

[0016] Optionally, each energy storage unit further includes an adjustable filter circuit, wherein the adjustable filter circuit is arranged between the battery pack and the DC side of the bridge circuit to modulate the filter frequency between the battery pack and the DC side of the bridge circuit.

[0017] The embodiment of the present application provides an energy storage system, which includes three single-phase bridge arms, each of which has a different structure. Each single-phase bridge arm includes a plurality of energy storage units connected in series and a filter circuit, and the filter circuit is arranged between the AC side of each single-phase bridge arm and the plurality of energy storage units, wherein the structure of each single-phase bridge arm has at least one of the following differences: the number of the plurality of energy storage units is different; the structure of the plurality of energy storage units is different. By changing the number of the plurality of energy storage units and / or the structure of the energy storage units of each single-phase bridge arm, single-phase bridge arms with different structures in the energy storage system are constructed, and a filter circuit is arranged in each single-phase bridge arm to filter the electric energy flowing through the single-phase bridge arm, thereby solving the technical problems in the prior art that the energy storage system may have three-phase imbalance, reduced capacity and high cost, and achieving the technical effect of preventing three-phase imbalance, increasing capacity and reducing cost.

[0018] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 1 A schematic structural diagram of an energy storage system provided in an embodiment of the present application is shown.

[0021] Figure 2 A structural schematic diagram of another energy storage system provided in an embodiment of the present application is shown.

[0022] Figure 3 A schematic diagram of the structure of a control module of an energy storage system provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0023] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme 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 only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application usually described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, each other embodiment obtained by those skilled in the art without making creative work belongs to the scope of protection of the present application.

[0024] In the prior art, the structures of the single-phase bridge arms of the energy storage system are the same, which results in fewer application scenarios for the energy storage system and makes it impossible to output certain voltages of electrical energy. In some application scenarios with special requirements, the energy storage unit needs to be redesigned. Moreover, in the three-phase bridge arms with the same structure, if any energy storage unit fails, the capacity will not meet the requirements and the three-phase imbalance will occur.

[0025] In view of the above problems, the embodiments of the present application provide an energy storage system, which can construct single-phase bridge arms with different structures in the energy storage system by changing the number of multiple energy storage units and / or the structure of the energy storage units in each single-phase bridge arm, thereby solving the technical problem in the prior art that the energy storage system needs to be redesigned when the application scenario of the energy storage system changes, and achieving the technical effect of increasing the application scenarios of the energy storage system, which is as follows:

[0026] See also Figure 1 , Figure 1 A schematic diagram of the structure of an energy storage system provided in an embodiment of the present application. The energy storage system provided in an embodiment of the present application includes three single-phase bridge arms, each of which has a different structure, and each single-phase bridge arm includes a plurality of energy storage units connected in series, wherein the structure of each single-phase bridge arm has at least one of the following differences: the number of the plurality of energy storage units is different; the structure of the plurality of energy storage units is different.

[0027] like Figure 1 As shown, the energy storage system includes an A-phase bridge arm, a B-phase bridge arm and a C-phase bridge arm, wherein the A-phase bridge arm includes n energy storage units connected in series, the B-phase bridge arm includes m energy storage units connected in series, and the C-phase bridge arm includes i energy storage units connected in series. The number of energy storage units in each single-phase bridge arm may be different, and the structure of the energy storage unit in each phase bridge arm may also be different. Each single-phase bridge arm may also include energy storage units with different structures.

[0028] By setting different numbers of energy storage units and / or setting energy storage units with different structures, the range of electric energy output by the energy storage system is increased, thereby increasing the application scenarios that the energy storage system can be set up. For each single-phase bridge arm, one end of the single-phase bridge arm serves as the input and output interface of the single-phase bridge arm, and the other end of the single-phase bridge arm is connected to the other end of the other single-phase bridge arm. The input and output interfaces of each single-phase bridge arm can be connected to electrical equipment or charging equipment respectively, so that each single-phase bridge arm can be charged and discharged separately.

[0029] Each energy storage unit includes a bridge circuit, wherein the structure of the energy storage unit is changed by setting different bridge circuits, wherein, for each single-phase bridge arm, the bridge circuit of multiple energy storage units corresponding to the single-phase bridge arm is a full-bridge circuit and / or a half-bridge circuit.

[0030] See also Figure 2 , Figure 2 This is a schematic diagram of the structure of another energy storage system provided in an embodiment of the present application. Figure 2 As shown, in the energy storage system provided in the embodiment of the present application, the A phase bridge arm includes energy storage units A1 to A n , and the bridge circuits of the energy storage units of the A-phase bridge arm are all full-bridge circuits 101, and the B-phase bridge arm includes energy storage units B1 to B m , and the bridge circuits of the energy storage units of the B-phase bridge arm are all half-bridge circuits 201, and the C-phase bridge arm includes energy storage units C1 to C i , and the bridge circuit of each energy storage unit of the C-phase bridge arm includes a full-bridge circuit 101 and a half-bridge circuit 201.

[0031] Each energy storage unit also includes a battery pack BAT, which includes at least one battery. The battery pack is connected to the DC side of the bridge circuit corresponding to each energy storage unit, and the energy storage units corresponding to each single-phase bridge arm are connected in series in sequence through the AC side of the bridge circuit.

[0032] That is, the AC side of the bridge circuit corresponding to each energy storage unit is connected in series and then connected to the input and output interface of the single-phase bridge arm. The AC side of the bridge circuit can be set to different level modes.

[0033] For each single-phase bridge arm, when the bridge circuits of the multiple energy storage units corresponding to the single-phase bridge arm are not all full-bridge circuits, the single-phase bridge arm also includes a level control circuit, which is arranged between the input and output interface of the single-phase bridge arm and the multiple energy storage units of the single-phase bridge arm.

[0034] like Figure 2As shown, the bridge circuits of the energy storage units in the B-phase bridge arm and the C-phase bridge arm are not all full-bridge circuits. Furthermore, in order to achieve the same level mode as the full-bridge circuit, it is necessary to set a level control circuit 301 between the input and output interface of the B-phase bridge arm and the multiple energy storage units of the B-phase bridge arm, and set a level control circuit 302 between the input and output interface of the C-phase bridge arm and the multiple energy storage units of the C-phase bridge arm. The level mode of the input and output interface of the single-phase bridge arm is changed by the level control circuit, and different level modes correspond to different voltage values.

[0035] The DC side of the bridge circuit includes a first DC connection terminal and a second DC connection terminal, and the AC side of the bridge circuit includes a first AC connection terminal and a second AC connection terminal. For each energy storage unit of each single-phase bridge arm, the first DC connection terminal and the second DC connection terminal of the energy storage unit are connected to the battery pack, and the first AC connection terminal of the energy storage unit is connected to the second AC connection terminal of the next energy storage unit.

[0036] Exemplarily, for each energy storage unit, the first DC connection end of the energy storage unit is connected to the positive electrode of the battery pack, the second DC connection end of the energy storage unit is connected to the negative electrode of the battery pack, and the first AC connection end of the energy storage unit is connected to the second AC connection end of the next energy storage unit. For each single-phase bridge arm, the first AC connection end of the first energy storage unit among the multiple series-connected energy storage units of the single-phase bridge arm is connected to the input and output interface of the single-phase bridge arm, and the second AC connection end of the last energy storage unit among the multiple series-connected energy storage units of the single-phase bridge arm is connected to the second AC connection end of the last energy storage unit corresponding to the other single-phase bridge arms.

[0037] The level control circuit is configured as a full-bridge circuit. For each single-phase bridge arm, the first DC connection end of the level control circuit of the single-phase bridge arm is connected to the first AC connection end of the first energy storage unit among multiple energy storage units connected in series, the second DC connection end of the level control circuit is connected to the second AC connection end of the last energy storage unit among the multiple energy storage units connected in series, and the AC side of the level control circuit is connected to the input and output ends of the single-phase bridge arm.

[0038] like Figure 2 As shown, each energy storage unit A1 to A n The first AC connection end of the full bridge circuit of the energy storage unit A1 located at the first position is connected to the input and output interface A of the A phase bridge arm. io ; Each energy storage unit B1 to B of the B phase bridge arm m The first AC connection end of the half-bridge circuit of the energy storage unit B1 located at the first position is connected to the first DC connection end of the level control circuit of the B-phase bridge arm, and the energy storage unit B located at the last position is connected to the first AC connection end of the half-bridge circuit of the energy storage unit B1 located at the first position. mThe second AC connection end of the half-bridge circuit is connected to the second DC connection end of the level control circuit of the B-phase bridge arm, and the first AC side connection end of the level control circuit is connected to the input and output interface B of the B-phase bridge arm. io The second AC side connection terminal of the level control circuit is connected to the last energy storage unit A of the A phase bridge arm. n The second AC connection end of the full-bridge circuit; the energy storage units C1 to C i The first AC connection end of the bridge circuit of the energy storage unit C1 located at the first position is connected to the first DC connection end of the level control circuit of the C phase bridge arm, and the last energy storage unit C i The second AC connection end of the bridge circuit is connected to the second DC connection end of the level control circuit of the C phase bridge arm, and the first AC side connection end of the level control circuit is connected to the input and output interface C of the C phase bridge arm. io The second AC side connection terminal of the level control circuit is connected to the last energy storage unit A of the A phase bridge arm. n The second AC connection terminal of the full-bridge circuit.

[0039] The full-bridge circuit 101 includes a first control switch Q1, a second control switch Q2, a third control switch Q3 and a fourth control switch Q4, wherein a first connection end of the first control switch is connected to a first connection end of the second control switch, a second connection end of the first control switch is connected to a first connection end of the third control switch, a second connection end of the third control switch is connected to a second connection end of the fourth control switch, and a second connection end of the second control switch is connected to a first connection end of the fourth control switch, wherein a connection between the first control switch and the second control switch serves as a first DC connection end of the full-bridge circuit, a connection between the third control switch and the fourth control switch serves as a second DC connection end of the full-bridge circuit, a connection between the first control switch and the third control switch serves as a first AC connection end of the full-bridge circuit, and a connection between the second control switch and the fourth control switch serves as a second AC connection end of the full-bridge circuit.

[0040] The control of the full-bridge circuit includes the following four results, namely forward access, forward bypass, reverse bypass and reverse access, wherein, when the first control switch and the fourth control switch are closed and the second control switch and the third control switch are disconnected, the full-bridge circuit is in a forward access state, and the AC side voltage value of the full-bridge circuit is equal to the voltage value of the battery pack; when the first control switch and the second control switch are closed and the third control switch and the fourth control switch are disconnected, the full-bridge circuit is in a forward bypass state, and the AC side voltage value of the full-bridge circuit is 0; when the second control switch and the third control switch are closed and the first control switch and the fourth control switch are disconnected, the full-bridge circuit is in a reverse access state, and the AC side voltage value of the full-bridge circuit is equal to the negative value of the voltage value of the battery pack; when the first control switch and the second control switch are disconnected and the third control switch and the fourth control switch are closed, the full-bridge circuit is in a reverse bypass state, and the AC side voltage value of the full-bridge circuit is 0.

[0041] The half-bridge circuit 201 includes a fifth control switch Q5 and a sixth control switch Q6, wherein the first connection end of the fifth control switch serves as a first DC connection end of the half-bridge circuit, the second connection end of the fifth control switch is connected to the first connection end of the sixth control switch, the second connection end of the sixth control switch serves as a second DC connection end of the half-bridge circuit, the connection between the fifth control switch and the sixth control switch serves as a first AC connection end of the half-bridge circuit, and the connection between the sixth control switch and the battery serves as a second AC connection end of the half-bridge circuit.

[0042] Among them, in the half-bridge circuit, when a control switch connected to the positive pole of the battery is closed, the AC side voltage value of the half-bridge circuit is the voltage value of the battery pack, and when a control switch connected to the negative pole of the battery is closed, the AC side voltage value of the half-bridge circuit is 0. Closing the two control switches at the same time will cause the battery pack to short-circuit.

[0043] The control switch provided in the embodiment of the present application can be set as a power semiconductor switch. Furthermore, a half-bridge circuit is used to reduce power switch devices and reduce costs. At the same time, since the use of a half-bridge circuit requires a level control circuit to be equipped on the bus, the control difficulty and accuracy are increased. The use of a full-bridge circuit will lead to an increase in power switch devices, but the synchronization requirements for each energy storage unit are reduced, and the control process is relatively simple.

[0044] Each single-phase bridge arm also includes a single-pole multi-throw switch and a control module (not shown in the figure), wherein the single-pole multi-throw switch includes multiple branches, and for each branch, the branch is empty, connected to a filter circuit, or connected to a protection circuit.

[0045] like Figure 2 As shown, a single-pole multi-throw switch K is set on the A phase bridge arm. a , a single-pole multi-throw switch K is set on the B phase bridge arm b, a single-pole multi-throw switch K is set on the C phase bridge arm c . By setting a single-pole multi-throw switch to switch different branches, the single-phase bridge arm can be disconnected, the electric energy flowing through the single-phase bridge arm can be filtered, or the excess electric energy on the single-phase bridge arm can be released through the protection circuit. Exemplarily, the control module is configured to: control the empty branch of the single-pole multi-throw switch to connect to the single-phase bridge arm, control the branch of the single-pole multi-throw switch connected to the filtering circuit to connect to the single-phase bridge arm, or control the branch of the single-pole multi-throw switch connected to the protection circuit to connect to the single-phase bridge arm.

[0046] The energy storage system further includes a three-phase electric switch K and a three-phase electric protection circuit 401, wherein the three-phase electric switch is used to change the on-off state of each single-phase bridge arm. The control module is configured to control the three-phase electric switch to be closed or opened. The control module is connected to the three-phase electric protection circuit, wherein the control module is configured to control the three-phase electric protection circuit to connect each single-phase bridge arm after controlling the three-phase electric switch to be opened.

[0047] Among them, the control module includes a first-level control module, multiple second-level control modules connected to the first-level control module, and multiple third-level control modules connected to each second-level control module. One second-level control module corresponds to a single-phase bridge arm, and one third-level control module corresponds to at least one energy storage unit under the single-phase bridge arm of the second-level control module.

[0048] For example, see Figure 3 , Figure 3 This is a schematic diagram of the structure of the control module of the energy storage system provided in the embodiment of the present application. Figure 3 As shown, the three-phase bridge arm of the energy storage system includes an A-phase bridge arm, a B-phase bridge arm and a C-phase bridge arm, wherein the first-level control module 501 is respectively connected to the second-level control module 502A corresponding to the A-phase bridge arm, the second-level control module 502B corresponding to the B-phase bridge arm and the second-level control module 502C corresponding to the C-phase bridge arm. Each single-phase bridge arm includes a plurality of energy storage units connected in series, the second-level control module 502A corresponding to the A-phase bridge arm is connected to a plurality of third control modules 503A corresponding to the A-phase bridge arm, each 503A corresponds to at least one energy storage unit 601A under the A-phase bridge arm, the second-level control module 502B corresponding to the B-phase bridge arm is connected to a plurality of third control modules 503B corresponding to the B-phase bridge arm, each 503B corresponds to at least one energy storage unit 601B under the B-phase bridge arm, and the second-level control module 502C corresponding to the C-phase bridge arm is connected to a plurality of third control modules 503C corresponding to the C-phase bridge arm, each 503C corresponds to at least one energy storage unit 601C under the C-phase bridge arm.

[0049] Exemplarily, the first-level control module is used to determine whether the three-phase electricity corresponding to the three-phase bridge arm of the energy storage system is within an uncontrollable range (such as lightning strikes, short circuits, sudden circuit breaks, etc.). When it is determined that the three-phase electricity is within an uncontrollable range, the three-phase electricity switch is controlled to be disconnected, each single-phase bridge arm is controlled to be in a disconnected state, and the three-phase electricity protection circuit is controlled to connect each single-phase bridge arm to control the three-phase electricity protection circuit to consume excess electrical energy on each single-phase bridge arm; when it is determined that the three-phase electricity is connected to the grid or connected to a charging device, the three-phase electricity switch is controlled to be closed.

[0050] For example, return Figure 2 The three-phase electric switch includes an A-phase electric multiple-selection switch, a B-phase electric multiple-selection switch and a C-phase electric multiple-selection switch. The A-phase electric multiple-selection switch includes a fixed end, a first candidate end and a second candidate end, wherein the fixed end and the first candidate end of the A-phase electric multiple-selection switch are arranged on the A-phase bridge arm, and the second candidate end is connected to the three-phase electric protection circuit; the B-phase electric multiple-selection switch includes a fixed end, a first candidate end and a second candidate end, wherein the fixed end and the first candidate end of the B-phase electric multiple-selection switch are arranged on the B-phase bridge arm, and the second candidate end is connected to the three-phase electric protection circuit; the C-phase electric multiple-selection switch includes a fixed end, a first candidate end and a second candidate end, wherein the fixed end and the first candidate end of the C-phase electric multiple-selection switch are arranged on the C-phase bridge arm, and the second candidate end is connected to the three-phase electric protection circuit. The first candidate end and the second candidate end of the A-phase electric multiple-selection switch, the B-phase electric multiple-selection switch and the C-phase electric multiple-selection switch are cooperatively controlled.

[0051] That is to say, by controlling the conduction between the fixed end and the first candidate end of the A-phase electric multiple-selection switch, the B-phase electric multiple-selection switch and the C-phase electric multiple-selection switch, the three-phase electric switch is controlled to be closed; by controlling the disconnection between the fixed end and the first candidate end of the A-phase electric multiple-selection switch, the B-phase electric multiple-selection switch and the C-phase electric multiple-selection switch, the three-phase electric switch is controlled to be closed; by controlling the conduction between the fixed end and the second candidate end of the A-phase electric multiple-selection switch, the three-phase electric protection circuit is controlled to be connected to each single-phase bridge arm through the three-phase electric switch.

[0052] Among them, after controlling the three-phase electric switch to close, the second-level control module controls the branch of the single-pole multi-throw switch connected to the filter circuit to connect to the single-phase bridge arm to filter the electric energy on each single-phase bridge arm; the second-level control module is used to determine whether there is a voltage or current abnormality in the single-phase electricity of each single-phase bridge arm. When determining that the single-phase electricity of the single-phase bridge arm is abnormal, the single-pole multi-throw switch of the single-phase bridge arm is first controlled to be empty to prevent damage to components of other single-phase bridge arms, that is, the empty branch of the single-pole multi-throw switch is controlled to connect to the single-phase bridge arm, and then the branch of the single-pole multi-throw switch of the single-phase bridge arm connected to the protection circuit is connected to the single-phase bridge arm, that is, the branch of the single-pole multi-throw switch connected to the protection circuit is controlled to connect to the single-phase bridge arm, so as to consume excess electric energy on the single-phase bridge arm through the protection circuit.

[0053] Among them, each third-level control module will collect the voltage, current, temperature and other information of the energy storage unit, and send the information to the second-level control module, so that the second-level control module can determine whether each energy storage unit has an abnormality. When the second-level control module determines that the voltage, current or temperature of any energy storage unit under the single-phase bridge arm is abnormal, the single-phase bridge arm where the abnormal energy storage unit is located is controlled to be disconnected, that is, the empty branch of the single-pole multi-throw switch of the single-phase bridge arm where the abnormal energy storage unit is located is controlled to be connected to the single-phase bridge arm.

[0054] Furthermore, the present application expands the application scenarios of the energy storage system by changing the structure of different single-phase bridge arms to meet the system application problems of different voltage / energy levels; and realizes redundant design by increasing the number of energy storage units, changing the capacity of different single-phase bridge arms to make alternative designs; and reduces the maintenance and replacement costs by reducing the energy storage units with complex structures and increasing the energy storage units with simple structures. In addition, the energy storage system of the present application can reduce the consistency requirements in the system design by being compatible with energy storage units of different structures / numbers, and is particularly suitable for the use of retired batteries.

[0055] In the description of this application, it should be noted that the terms "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0056] It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" 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 direct connection, or an indirect connection 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.

[0057] The above description is only an embodiment of the present application and is not intended to limit the protection scope of 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 includes three single-phase bridge arms, each of which has a different structure. Each single-phase bridge arm includes a plurality of energy storage units connected in series and a filter circuit, wherein the filter circuit is arranged between the AC side of each single-phase bridge arm and the plurality of energy storage units. The structures of the single-phase bridge arms are different from each other in at least one of the following ways: The number of multiple energy storage units is different; The structures of the multiple energy storage units are different.

2. The energy storage system according to claim 1, characterized in that: Each single-phase bridge arm further includes a single-pole multi-throw switch and a control module, wherein the single-pole multi-throw switch includes a plurality of branches, and for each branch, the branch is a blank branch, connected to the filter circuit, or connected to a protection circuit. Among them, the control module is configured to: control the empty branch of the single-pole multi-throw switch to connect to the single-phase bridge arm, control the branch of the single-pole multi-throw switch connected to the filter circuit to connect to the single-phase bridge arm, or control the branch of the single-pole multi-throw switch connected to the protection circuit to connect to the single-phase bridge arm.

3. The energy storage system according to claim 1, characterized in that: Each energy storage unit includes a bridge circuit, wherein the structure of the energy storage unit is changed by setting different bridge circuits. Among them, for each single-phase bridge arm, the bridge circuit of multiple energy storage units corresponding to the single-phase bridge arm is a full-bridge circuit and / or a half-bridge circuit.

4. The energy storage system according to claim 3, characterized in that: Each energy storage unit also includes a battery pack, which includes at least one battery. The battery pack is connected to the DC side of the bridge circuit corresponding to each energy storage unit, and the energy storage units corresponding to each single-phase bridge arm are connected in series in sequence through the AC side of the bridge circuit.

5. The energy storage system according to claim 4, characterized in that: For each single-phase bridge arm, when the bridge circuits of the multiple energy storage units corresponding to the single-phase bridge arm are not all full-bridge circuits, the single-phase bridge arm also includes a level control circuit, which is arranged between the input and output interface of the single-phase bridge arm and the multiple energy storage units of the single-phase bridge arm.

6. The energy storage system according to claim 5, characterized in that: The DC side of the bridge circuit includes a first DC connection terminal and a second DC connection terminal, and the AC side of the bridge circuit includes a first AC connection terminal and a second AC connection terminal. For each energy storage unit in each single-phase bridge arm, the first DC connection terminal and the second DC connection terminal of the energy storage unit are connected to the battery pack, and the first AC connection terminal of the energy storage unit is connected to the second AC connection terminal of the next energy storage unit.

7. The energy storage system according to claim 6, characterized in that: The level control circuit is configured as a full-bridge circuit. For each single-phase bridge arm, the first DC connection end of the level control circuit of the single-phase bridge arm is connected to the first AC connection end of the first energy storage unit among multiple energy storage units connected in series, the second DC connection end of the level control circuit is connected to the second AC connection end of the last energy storage unit among the multiple energy storage units connected in series, and the AC side of the level control circuit is connected to the input and output ends of the single-phase bridge arm.

8. The energy storage system according to claim 5, characterized in that: The full-bridge circuit includes a first control switch, a second control switch, a third control switch and a fourth control switch, wherein a first connection end of the first control switch is connected to a first connection end of the second control switch, a second connection end of the first control switch is connected to a first connection end of the third control switch, a second connection end of the third control switch is connected to a second connection end of the fourth control switch, and a second connection end of the second control switch is connected to a first connection end of the fourth control switch. Among them, the connection between the first control switch and the second control switch serves as the first DC connection end of the full-bridge circuit, the connection between the third control switch and the fourth control switch serves as the second DC connection end of the full-bridge circuit, the connection between the first control switch and the third control switch serves as the first AC connection end of the full-bridge circuit, and the connection between the second control switch and the fourth control switch serves as the second AC connection end of the full-bridge circuit.

9. The energy storage system according to claim 5, characterized in that: The half-bridge circuit includes a fifth control switch and a sixth control switch, wherein the first connection end of the fifth control switch serves as a first DC connection end of the half-bridge circuit, the second connection end of the fifth control switch is connected to the first connection end of the sixth control switch, the second connection end of the sixth control switch serves as a second DC connection end of the half-bridge circuit, the connection between the fifth control switch and the sixth control switch serves as a first AC connection end of the half-bridge circuit, and the connection between the sixth control switch and the battery serves as a second AC connection end of the half-bridge circuit.

10. The energy storage system according to claim 2, characterized in that: The energy storage system further includes a three-phase electric switch, which is used to change the on-off state of each single-phase bridge arm. The control module is connected to the three-phase electric switch. Wherein, the control module is configured to control the three-phase electrical switch to be closed or opened.

11. The energy storage system according to claim 10, characterized in that: The energy storage system also includes a three-phase electrical protection circuit, and the control module is connected to the three-phase electrical protection circuit. Wherein, the control module is configured to: after controlling the three-phase electrical switch to be disconnected, control the three-phase electrical protection circuit to connect each single-phase bridge arm.

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