Energy storage system

Abstract

The utility model provides an energy storage system, and the system comprises a plurality of energy storage units which are connected in series. A plurality of control unit groups, one control unit group corresponds to one energy storage unit, the acquisition interface of the control unit group is connected with the acquisition interface of the corresponding energy storage unit, and the control interface of the control unit group is connected with the control interface of the corresponding energy storage unit; a first sampling communication interface of the processor is connected with the second sampling communication interface of each control unit group, and a first control communication interface of the processor is connected with the second control communication interface of each control unit group.

Description

Technical Field

[0001] This application relates to the field of energy storage system technology, and more particularly to an energy storage system. Background Technology

[0002] Modular Multilevel Converter (MMC) energy storage systems offer advantages such as high efficiency, modularity, flexible scalability, low switching losses, and high output waveform quality, leading to their widespread application in large drives, DC transmission, and wind power grid connection. An MMC energy storage system comprises a processor and multiple energy storage units, each including an inverter. Existing MMC energy storage systems utilize software to control the inverter's on / off state, enabling flexible control of each battery's connection and bypass status. This allows the MMC energy storage system to adapt to the power supply of external devices, achieving multilevel input or output.

[0003] In existing technologies, when controlling whether each energy storage unit in an energy storage system outputs electrical energy, the processor needs to send control signals to the inverter of the energy storage unit to control whether each energy storage unit outputs electrical energy and the sign of the output voltage. Each energy storage unit also needs to upload its operational status information to the processor. Therefore, the process of uploading the status information from each energy storage unit to the processor may interfere with the transmission of control signals, leading to policy conflicts on the communication bus between the processor and each energy storage unit. This further affects the response rate of the inverter during operation and thus the stability of the energy storage system's output voltage. Utility Model Content

[0004] In view of this, the purpose of this application is to provide an energy storage system that can configure a control unit group for each energy storage unit. The acquisition interface and control interface of the control unit group are connected to the acquisition interface and control interface of the energy storage unit respectively. The first sampling communication interface and the first control communication interface of the processor are connected to the second sampling communication interface and the second control communication interface of each control unit group respectively. The processor is connected to the communication interface of each control unit group, so as to realize that the processor samples and sends control signals to the energy storage unit through different signal transmission lines through the control unit group. This solves the technical problem that the energy storage system has low transmission efficiency due to sampling and control only through the communication bus in the prior art, and achieves the technical effect of improving the signal transmission efficiency of the energy storage system.

[0005] In a first aspect, embodiments of this application provide an energy storage system, comprising: a plurality of energy storage units connected in series; a plurality of control unit groups, each control unit group corresponding to one energy storage unit, wherein the acquisition interface of the control unit group is connected to the acquisition interface of its corresponding energy storage unit, and the control interface of the control unit group is connected to the control interface of its corresponding energy storage unit; and a processor, wherein the first sampling communication interface of the processor is connected to the second sampling communication interface of each control unit group, and the first control communication interface of the processor is connected to the second control communication interface of each control unit group.

[0006] Optionally, each control unit group includes a monitoring control unit and an operation control unit, wherein the acquisition interface of the monitoring control unit serves as the acquisition interface of the control unit group, and the control interface of the operation control unit serves as the control interface of the control unit group. The processor is configured to: acquire the operation information of each energy storage unit through the monitoring control unit, and control the AC side voltage status of each energy storage unit through the operation control unit.

[0007] Optionally, the processor's first sampling communication interface is connected to the second sampling communication interface of each monitoring and control unit, and the processor's first control communication interface is connected to the second control communication interface of each operating control unit. The monitoring and control unit is configured to send the collected operating information of the energy storage unit to the processor, and the operating control unit is configured to control the AC side voltage state of the energy storage unit according to the control signal sent by the processor's first control communication interface for the energy storage unit.

[0008] Optionally, the monitoring and control unit further includes a first monitoring interface and a second monitoring interface, wherein the first monitoring interface is connected between the control interface of the operation control unit and the control interface of a corresponding energy storage unit, and the second monitoring interface is connected between the first control communication interface of the processor and the second control communication interface of the corresponding control unit group. The monitoring and control unit is configured to determine the operating status of the operation control unit based on the signal data received by the first monitoring interface and the second monitoring interface respectively.

[0009] Optionally, it further includes: multiple branch control switches, one branch control switch being correspondingly set on one energy storage branch, the energy storage branch being the branch where an energy storage unit and its corresponding control unit group are located; wherein, the monitoring and control unit is configured to: control the action of the branch control switch according to the operating status of the operating control unit, so as to control whether the energy storage branch is connected to the energy storage system.

[0010] Optionally, each energy storage unit further includes: at least one battery cell; a bridge circuit, wherein the DC side of the bridge circuit is connected to at least one battery cell, and the AC side of the bridge circuit serves as the AC side of the energy storage unit; wherein the AC sides of the bridge circuits corresponding to multiple energy storage units are connected sequentially, and the operation control unit is configured to control the AC side voltage state of the energy storage unit by controlling the conduction state of the bridge circuit.

[0011] Optionally, the bridge circuit includes a first control switch, a second control switch, a third control switch, and a fourth control switch, wherein one end of the first control switch is connected to one end of the second control switch, the other end of the first control switch is connected to one end of the third control switch, the other end of the second control switch is connected to one end of the fourth control switch, and the other end of the third control switch is connected to the other end of the fourth control switch.

[0012] Optionally, the connection between the first control switch and the second control switch serves as one end of the DC side of the bridge circuit, the connection between the third control switch and the fourth control switch serves as the other end of the DC side of the bridge circuit, and the connection between the first control switch and the third control switch, as well as the connection between the second control switch and the fourth control switch, serve as the AC side of the bridge circuit.

[0013] Optionally, it further includes: a first isolation circuit, one end of which is connected to the first synchronization interface of the processor; and a plurality of second isolation circuits, each second isolation circuit corresponding to a running control unit, one end of each second isolation circuit being connected to the other end of the first isolation circuit, and the other end of each second isolation circuit being connected to the second synchronization interface of its corresponding running control unit, so that the second synchronization interface of each running control unit receives the synchronization signal sent by the first synchronization interface.

[0014] Optionally, it further includes: a first power interface and a second power interface for connecting to an external power source or external electrical equipment; wherein the first power interface is led out from the AC side of the first energy storage unit of the plurality of energy storage units, and the second power interface is led out from the AC side of the last energy storage unit of the plurality of energy storage units.

[0015] This application provides an energy storage system comprising: multiple energy storage units connected in series; multiple control unit groups, each control unit group corresponding to one energy storage unit, wherein the acquisition interface of each control unit group is connected to the acquisition interface of its corresponding energy storage unit, and the control interface of each control unit group is connected to the control interface of its corresponding energy storage unit; and a processor, wherein the first sampling communication interface of the processor is connected to the second sampling communication interface of each control unit group, and the first control communication interface of the processor is connected to the second control communication interface of each control unit group. By configuring one control unit group for each energy storage unit, with the acquisition and control interfaces of each control unit group corresponding to the acquisition and control interfaces of the energy storage unit, and the first sampling and control communication interfaces of the processor corresponding to the second sampling and control communication interfaces of each control unit group, and the processor being connected to the communication interfaces of each control unit group, the processor can sample and send control signals to the energy storage unit through different signal transmission lines via the control unit groups. This solves the technical problem of low transmission efficiency in the prior art due to sampling and control only through a communication bus, and achieves the technical effect of improving the signal transmission efficiency of the energy storage system.

[0016] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the structure of an energy storage system provided in an embodiment of this application is shown.

[0019] Figure 2 A schematic diagram of another energy storage system provided in an embodiment of this application is shown. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.

[0021] In existing technologies, energy storage systems determine the connection and disconnection sequence of each energy storage unit based on the power requirements of external electrical equipment. This is then used by the inverter to control the connection and disconnection of each energy storage unit. However, since the operating status of the energy storage system also needs to be monitored, relying solely on a communication bus for inverter control signal transmission and energy storage unit monitoring can lead to communication bus conflicts during system operation.

[0022] The existing two-level architecture features a cascaded structure with upper and lower levels to perform BMS sampling, analysis, and processing under different operating conditions. The priority of sampling and control can be adjusted via the communication topology while ensuring system functionality. Under normal circumstances, sampling and control have the same priority, occupying the bus at different times to achieve regulation within a system cycle. In situations such as sudden power grid fluctuations or high / low voltage ride-through problems, the sampling priority decreases (waiting for several cycles to process and recover data simultaneously), while the control priority increases.

[0023] In other words, the communication bus may encounter sudden grid fluctuations, high- and low-voltage ride-through problems, or other emergencies that require timely response from the inverter during the period when it receives the sampled data. Consequently, it needs to urgently process control information. However, the processing takes time, and it also takes time to notify the inverter to stop uploading the sampled information. This can lead to problems such as the inverter not responding in time or not being able to transmit signals accurately, which affects the normal operation of the energy storage system. Furthermore, the untimely issuance of control signals may also cause damage to the energy storage system equipment.

[0024] To address the aforementioned problems, this application provides an energy storage system that configures a control unit group for each energy storage unit. The acquisition and control interfaces of the control unit group are connected to the acquisition and control interfaces of the energy storage unit, respectively. The processor's first sampling communication interface and first control communication interface are connected to the second sampling communication interface and second control communication interface of each control unit group. Furthermore, the processor is connected to the communication interfaces of each control unit group. This allows the processor to sample and send control signals to the energy storage unit through different signal transmission lines via the control unit groups. This solves the technical problem of low transmission efficiency in existing technologies that rely solely on a communication bus for sampling and control, thus improving the signal transmission efficiency of the energy storage system. Specifically, the following applies:

[0025] Please see Figure 1 , Figure 1 This is a schematic diagram of an energy storage system provided in an embodiment of this application. Figure 1 As shown, the energy storage system provided in this application embodiment includes: multiple energy storage units 101 connected in series; multiple control unit groups 102, each control unit group corresponding to one energy storage unit, the acquisition interface 21A of the control unit group being connected to the acquisition interface 1A of its corresponding energy storage unit, and the control interface 21B of the control unit group being connected to the control interface 1B of its corresponding energy storage unit; and a processor 103, the first sampling communication interface 3A of the processor being connected to the second sampling communication interface 23A of each control unit group, and the first control communication interface 3B of the processor being connected to the second control communication interface 23B of each control unit group.

[0026] Each energy storage unit has a positive terminal V1+ and a negative terminal V1- on its AC side. The positive terminal V1+ of each energy storage unit is connected to the negative terminal V1- of the preceding energy storage unit, thus enabling multiple energy storage units to be connected in series. Furthermore, the positive terminal of the first energy storage unit and the negative terminal of the last energy storage unit in the series connection serve as interfaces for connecting the energy storage system to external devices, enabling the charging of multiple energy storage units or controlling the multiple energy storage units to supply power to external systems.

[0027] The energy storage system also includes a first power interface V+ and a second power interface V-, for connecting to an external power source or external electrical equipment; wherein, the first power interface is led out from the AC side of the first energy storage unit of the plurality of energy storage units, and the second power interface is led out from the AC side of the last energy storage unit of the plurality of energy storage units.

[0028] In other words, for each energy storage unit, its negative terminal is connected to the positive terminal of the next energy storage unit. A first power interface is drawn from the positive terminal of the first energy storage unit, and a second power interface is drawn from the negative terminal of the last energy storage unit, thus achieving a series connection of multiple energy storage units. Furthermore, when the first and second power interfaces are connected to an external power source, the external power source can charge the multiple energy storage units; when the first and second power interfaces are connected to external electrical equipment, the multiple energy storage units can supply power to external user equipment.

[0029] In other words, the acquisition interface of the control unit receives the operating information of the energy storage units sent by the acquisition interface of the energy storage units, and sends it to the first sampling communication interface of the processor through the second sampling communication interface, so that the processor receives the operating information of each energy storage unit. The second control communication interface of the control unit receives the control signals generated by the first control communication interface of the processor, and sends control signals to the control interface of its corresponding energy storage unit to change the power transmission status of the energy storage unit, that is, to control the energy storage unit to connect to the energy storage system in the forward direction, connect to the energy storage system in the reverse direction, or bypass it.

[0030] Furthermore, the communication transmission of operational information for the energy storage unit is achieved through the acquisition interface of the energy storage unit, the acquisition interface of the control unit group, the second sampling communication interface of the control unit group, and the first sampling communication interface of the processor. Similarly, the communication transmission of control signals for the energy storage unit is achieved through the control interface of the energy storage unit, the control interface of the control unit group, the second control communication interface of the control unit group, and the first control communication interface of the processor. Thus, by dividing the communication paths, the transmission of operational information and control signals is isolated, preventing the problem of untimely signal processing caused by using a single communication bus to transmit operational information and control signals, thereby improving the information transmission efficiency of the energy storage system.

[0031] Please see Figure 2 , Figure 2 This is a schematic diagram of another energy storage system provided in an embodiment of this application. Figure 2 As shown, in the energy storage system provided in this application embodiment, each control unit group 102 includes a monitoring control unit 1021 and an operation control unit 1022. The acquisition interface of the monitoring control unit is used as the acquisition interface 21A of the control unit group, and the control interface of the operation control unit is used as the control interface 21B of the control unit group. The processor is configured to: acquire the operation information of each energy storage unit through the monitoring control unit, and control the AC side voltage state of each energy storage unit through the operation control unit.

[0032] For example, the processor, monitoring control unit, and operation control unit can all be configured as microcontroller units (MCUs). The processor's first sampling communication interface, the second sampling communication interface of each monitoring control unit, the acquisition interface of the monitoring control unit, and the acquisition interface of the energy storage unit communicate using the SPI (Serial Peripheral Interface) communication protocol; the processor's first control communication interface and the second control communication interface of each operation control unit communicate using the CAN (Controller Area Network) communication protocol; and the control interface of the operation control unit and the control interface of each energy storage unit transmit pulse width modulation (PWM) signals through a communication bus (BUS).

[0033] In other words, sampling is performed by a monitoring control unit and operation control is performed by an operation control unit. The two control units are set up independently and use different communication protocols to achieve independent data upload. Compared with the existing technology where only one module performs sampling and control data transmission through serial transmission, independent sampling and time-division data upload can be achieved without reducing the priority of sampling data transmission. By distinguishing the data transmitted by sampling and control and the transmission channels, the system can process the data in a timely manner.

[0034] Specifically, the processor's first sampling communication interface is connected to the second sampling communication interface of each monitoring and control unit, and the processor's first control communication interface is connected to the second control communication interface of each operating control unit. The monitoring and control unit is configured to send the collected operating information of the energy storage unit to the processor, and the operating control unit is configured to control the AC side voltage state of the energy storage unit according to the control signal sent by the processor's first control communication interface for the energy storage unit.

[0035] In other words, for each energy storage unit, the acquisition interface of the energy storage unit is connected to the acquisition interface of the monitoring and control unit of the control unit group to send the operating information of the energy storage unit to the monitoring and control unit of the corresponding control unit group. The second sampling communication interface of the monitoring and control unit is connected to the first sampling communication interface of the processor so that the monitoring and control unit sends the operating information to the processor. The first control communication interface of the processor is connected to the second control communication interface of the operating control unit of the control unit group corresponding to the energy storage unit so that the processor sends a control signal for the energy storage unit to the operating control unit corresponding to the energy storage unit. The control interface of the operating control unit sends a corresponding control signal to the control interface of the energy storage unit so that the energy storage unit adjusts the AC side voltage state according to the received control signal.

[0036] For example, operational information includes the cell capacity of the energy storage unit, the voltage and current values ​​of the output power, and equipment log information. AC side voltage status describes the voltage status on the AC side of the energy storage unit, including forward connection status, reverse connection status, and bypass status.

[0037] For example, the processor determines the access sequence and disconnection sequence of each energy storage unit based on the external power demand (which may be a single-phase AC waveform), as well as the access time of each energy storage unit, and sends different control signals to enable each energy storage unit to adjust its access or disconnection according to the control signals.

[0038] like Figure 2 As shown, the monitoring and control unit further includes a first monitoring interface 23C and a second monitoring interface 23D. The first monitoring interface 23C is connected between the control interface 21B of the operation control unit and the control interface 1B of a corresponding energy storage unit. The second monitoring interface 23D is connected between the first control communication interface 3B of the processor and the second control communication interface 23B of the corresponding control unit group. The monitoring and control unit is configured to determine the operating status of the operation control unit based on the signal data received by the first monitoring interface and the second monitoring interface respectively.

[0039] In other words, for each energy storage unit, the control interface of the energy storage unit is connected to the control interface of the operation control unit to which it is connected, and the second control communication interface of the operation control unit corresponding to the energy storage unit is connected to the first control communication interface of the processor to which it is connected, and the second monitoring interface of the monitoring control unit is connected to the first control communication interface of the processor to which it is connected.

[0040] Based on this, the monitoring control unit monitors the control signals transmitted between the processor and the operation control unit, as well as the control signals transmitted between the operation control unit and the energy storage unit, so that the monitoring control unit can determine whether the control signals received by the operation control unit are consistent with the control signals sent, thereby determining whether the operation control unit is in a normal state or a fault state.

[0041] Specifically, when the monitoring and control unit determines that the control signal received by the operating control unit matches the control signal sent by the operating control unit, the operating control unit is considered to be in a normal operating state; when the monitoring and control unit determines that the control signal received by the operating control unit does not match the control signal sent by the operating control unit, the operating control unit is considered to be in a fault state. Furthermore, the monitoring and control unit monitors whether the operating control unit has malfunctioned, and can also be configured to send a fault signal to the processor, so that when the processor determines which energy storage units to connect to the energy storage system, it does not consider the energy storage units corresponding to the operating control units in a fault state, thus avoiding affecting the normal operation of the energy storage system.

[0042] like Figure 2 As shown, the energy storage system also includes: multiple branch control switches K, each branch control switch being installed on a corresponding energy storage branch, wherein the energy storage branch is the branch containing an energy storage unit and its corresponding control unit group; wherein, the monitoring and control unit is configured to: control the action of the branch control switches according to the operating status of the operating control unit, so as to control whether the energy storage branch is connected to the energy storage system.

[0043] For example, for each energy storage branch, the switch control interface 20A of the monitoring and control unit 1021 on the energy storage branch is connected to the control terminal of the branch control switch K. In this way, the monitoring and control unit controls the opening or closing of the branch control switch K by sending a control signal to the control terminal of the branch control switch K.

[0044] In other words, for each energy storage branch, the energy storage branch includes an energy storage unit and a branch control switch connected in series. The monitoring and control unit corresponding to the energy storage branch is connected to the control terminal of the branch control switch. When the monitoring and control unit corresponding to the energy storage unit in the energy storage branch detects that the operating status of its corresponding operating control unit is in a fault state, the switch control interface of the monitoring and control unit sends a disconnect control signal to the control terminal of the branch control switch, so that the energy storage branch where the branch control switch is located disconnects the energy storage unit and prevents the operating control unit in a fault state from connecting to the energy storage system.

[0045] like Figure 2 As shown, each energy storage unit further includes: at least one battery cell 1011; a bridge circuit 1012, wherein the DC side of the bridge circuit is connected to at least one battery cell, and the AC side of the bridge circuit serves as the AC side of the energy storage unit; wherein the AC sides of the bridge circuits corresponding to multiple energy storage units are connected sequentially, and the operation control unit is configured to control the AC side voltage state of the energy storage unit by controlling the conduction state of the bridge circuit.

[0046] For example, at least one cell connected in series is connected to the DC side of a bridge circuit, and the AC side of the bridge circuit serves as the AC side of the energy storage unit. For each energy storage device, the AC side of the bridge circuit of that energy storage device is connected to the AC side of the bridge circuit of the previous energy storage system, so as to realize the series connection of multiple energy storage units so that the energy storage units can transmit electrical energy to the outside through the bridge circuit.

[0047] like Figure 2 As shown, the bridge circuit 1012 includes a first control switch Q1, a second control switch Q2, a third control switch Q3, and a fourth control switch Q4. One end of the first control switch is connected to one end of the second control switch, the other end of the first control switch is connected to one end of the third control switch, the other end of the second control switch is connected to one end of the fourth control switch, and the other end of the third control switch is connected to the other end of the fourth control switch.

[0048] The connection between the first control switch and the second control switch serves as one end of the DC side of the bridge circuit, the connection between the third control switch and the fourth control switch serves as the other end of the DC side of the bridge circuit, and the connection between the first control switch and the third control switch, as well as the connection between the second control switch and the fourth control switch, serve as the AC side of the bridge circuit.

[0049] For example, the connection between the first control switch and the second control switch is connected to the positive connection terminal + of at least one battery cell, and the connection between the third control switch and the fourth control switch is connected to the negative connection terminal - of at least one battery cell.

[0050] For example, for each energy storage unit, the connection between the first control switch and the third control switch of the bridge circuit corresponding to the energy storage unit is connected to the connection between the second control switch and the fourth control switch of the bridge circuit corresponding to the previous energy storage unit, so as to connect the various energy storage units in series.

[0051] In other words, the positive connection point V1+ of the energy storage unit is led out from the connection between the first control switch and the third control switch, and the negative connection point V1- of the energy storage unit is led out from the connection between the second control switch and the fourth control switch. The positive and negative connection points of multiple energy storage units in the energy storage system are connected in sequence. The positive connection point of the first energy storage unit and the negative connection point of the last energy storage unit serve as the interface for connecting the energy storage system to external devices.

[0052] In other words, for each energy storage unit, the control terminals of each control switch in the bridge circuit of that energy storage unit serve as the control interface for that energy storage unit, and the control interface of the operation control unit is connected to the control terminals of each control switch in the bridge circuit corresponding to that energy storage unit. Furthermore, the operation control unit is configured to control the conduction state of the bridge circuit by sending control signals to the control terminals of each control switch in the bridge circuit.

[0053] The bridge circuit has four conduction states: forward connection, forward bypass, reverse bypass, and reverse connection. Specifically, when the first and fourth control switches are closed and the second and third control switches are open, the full bridge circuit is in the forward connection state, meaning the energy storage unit is connected to the energy storage system and its voltage is equal to the battery voltage. When the first and second control switches are closed and the third and fourth control switches are open, the full bridge circuit is in the forward bypass state, meaning the energy storage unit is disconnected from the energy storage system and its voltage is 0. When the second and third control switches are closed and the first and fourth control switches are open, the full bridge circuit is in the reverse connection state, meaning the energy storage unit is connected to the energy storage system and its voltage is equal to the negative of the battery voltage. When the first and second control switches are open and the third and fourth control switches are closed, the full bridge circuit is in the reverse bypass state, meaning the energy storage unit is disconnected from the energy storage system and its voltage is 0.

[0054] Specifically, the energy storage system also includes: a first isolation circuit 1041, one end of which is connected to the first synchronization interface 3C of the processor; and a plurality of second isolation circuits 1042, each second isolation circuit corresponding to one operating control unit, one end of each second isolation circuit being connected to the other end of the first isolation circuit, and the other end of each second isolation circuit being connected to the second synchronization interface 24C of its corresponding operating control unit, so that the second synchronization interface of each operating control unit receives the synchronization signal sent by the first synchronization interface.

[0055] The isolation circuit may include an optocoupler. That is, the processor's first synchronization interface is connected to the optocouplers of the corresponding second isolation circuits of each operating control unit via the optocoupler of the first isolation circuit. Therefore, when the processor and each operating control unit send synchronization signals, they need to be isolated through two optocouplers to prevent abnormal synchronization signal transmission. The synchronization signal is used to synchronize the time of each operating control unit, enabling clock synchronization between the processor and each operating control unit.

[0056] For example, an isolation circuit can also be provided between the processor's first sampling communication interface and the second sampling communication interface of the monitoring and control unit corresponding to each energy storage unit. That is, the processor's first sampling communication interface is connected to one end of a first optocoupler, the other end of the first optocoupler is connected to one end of a second optocoupler corresponding to each energy storage unit, and the other end of the second optocoupler corresponding to each energy storage unit is connected to its corresponding second sampling communication interface. And / or, an isolation circuit can also be provided between the processor's first control communication interface and the second control communication interface of the operating control unit corresponding to each energy storage unit. That is, the processor's first control communication interface is connected to one end of a third optocoupler, the other end of the third optocoupler is connected to one end of a fourth optocoupler corresponding to each energy storage unit, and the other end of the fourth optocoupler corresponding to each energy storage unit is connected to its corresponding second control communication interface. Furthermore, the optocouplers are used to isolate the signal transmission between the monitoring and control unit and the processor connected to it, and to isolate the signal transmission between the operating control unit and the processor connected to it, so as to prevent the monitoring and control units from interfering with the processor when outputting signals.

[0057] For example, the processor obtains the operating information of each energy storage unit through the monitoring and control unit corresponding to each energy storage unit, and determines the cell order of multiple energy storage units connected to the new energy storage system based on the operating information of each energy storage unit. For example, the order can be based on the cell capacity of each energy storage unit. According to the voltage requirements of the external devices connected to the energy storage system, the cell access timetable can be determined according to the nearest level approximation method, that is, the access or bypass time of each energy storage unit can be determined according to the voltage sine wave curve corresponding to the voltage requirements. The cell timetable is sent to the operation control unit, and according to the AC side voltage status of the energy storage unit access or bypass at each time on the cell timetable, the control signal for the bridge circuit of the energy storage unit is sent to the operation control unit. Then, the operation control unit corresponding to each energy storage unit controls the bridge circuit according to the control signal, so that the bridge circuit of each energy storage unit can be accessed or bypassed, thereby completing the nearest level approximation operation of MMC and realizing the corresponding modulated AC power. The corresponding algorithm solves the requirement of regulating and generating AC power.

[0058] For example, for each voltage sine wave cycle, the cycle is divided into a positive rising phase, a positive falling phase, a negative rising phase, and a negative falling phase. The processor determines to sequentially connect and disconnect energy storage units numbered 1, 2, 3, ..., m from the energy storage system according to the cell order. Specifically, it first controls energy storage unit numbered 1 to connect to the energy storage system in the positive direction. After a time period t1 following the connection of energy storage unit numbered 1, it controls energy storage unit numbered 2 to connect to the energy storage system in the positive direction. After a time period t2 following the connection of energy storage unit numbered 2, it controls energy storage unit numbered 3 to connect to the energy storage system in the positive direction, and so on, until energy storage unit numbered m is connected to the energy storage system in the positive direction. At this point, all energy storage units numbered 1 to m are connected to the energy storage system, and the connection time period t1 for energy storage unit numbered m is... m Then, control the connection of energy storage unit m to the energy storage system, during the time period t when energy storage unit m is connected. m-1 Then, control the energy storage unit numbered m-1 to connect to the energy storage system, and so on, until the energy storage unit numbered 1 connects to the energy storage system. Then, control each energy storage unit to connect to the energy storage system in reverse according to the time period and order of the forward connection to the energy storage system, and control the energy storage units connected to the energy storage system in reverse according to the order and time interval of the connection to the energy storage system, and then control each energy storage unit to output single-phase AC power.

[0059] Furthermore, frequency regulation of single-phase AC power is achieved by increasing or decreasing the forward connection time, reverse connection time, and disconnection time of energy storage unit m. Specifically, the time during which energy storage units 1 to m sequentially connect forward to the energy storage system is considered the positive upward phase, and the time during which energy storage units m to 1 sequentially disconnect from the energy storage system is considered the positive downward phase; conversely, the time during which energy storage units 1 to m sequentially connect reverse to the energy storage system is considered the negative upward phase, and the time during which energy storage units m to 1 sequentially disconnect from the energy storage system is considered the negative downward phase.

[0060] Based on this, this application allows sampling and control to use two different communication transmission segments, and also enables the processor to receive operational information from each energy storage unit in a timely manner, avoiding the loss of the Battery Management System (BMS) function of the monitoring and control unit, and to promptly send control signals, preventing delays in bridge circuit operation caused by untimely control signal transmission, which could affect the operation of the energy storage system. Furthermore, by replacing the dual-core processor with a monitoring and control unit and an operation control unit, the application cost of the slave processor is avoided.

[0061] Furthermore, when the processor needs to quickly adjust and process data, the processor's sampling task will have its processing priority reduced. The monitoring and control unit is responsible for real-time management of the voltage, temperature, and other states of the local cells in the energy storage unit. If an abnormal cell state is detected for a period of time, it can communicate with the operation control unit in real time to inform the processor to adjust the control strategy or actively disconnect the entire energy storage branch. By uploading the operation log of the energy storage unit to the processor, it can promptly inform the device of information and improve the device's safety performance. The monitoring and control unit also performs a safety backup function. When the operation control unit has a problem (such as a control failure), it actively assumes the backup protection function, disconnects the energy storage branch where the faulty operation control unit is located from the energy storage system, and uploads the device's operation information as a secondary log (LOG) to the processor. After the fault of the operation control unit is corrected, the operation control unit will inform the monitoring and control unit and the processor so that the processor can reconsider the energy storage unit where the operation control unit is located. The monitoring and control unit will then control the branch control switch of the energy storage branch where the operation control unit is located to close.

[0062] This application addresses the problem of how energy storage systems can process sampling and control information in a timely manner. During the regulation of single-phase AC power, corresponding regulation is achieved by sequentially changing the connection order of energy storage units and the connection time of each unit. Furthermore, by changing the connection time of the energy storage unit corresponding to the highest point of the AC waveform and adjusting the current task architecture, some basic MMC inverters can be implemented, enabling peak shaving and frequency regulation operations. This solves the problem of active cell balancing and also addresses inverter on-grid switching and high / low voltage ride-through issues. This application sets up two control units to process operational and control information separately, unlike existing technologies that only have a processor and a controller for each energy storage unit in a two-level structure. This avoids the bus being occupied by operational and control information when using only one controller, thus affecting control efficiency. It also avoids the problem of information not being transmitted in a timely manner when only one controller is used, which could result in prioritizing the transmission of control or operational information.

[0063] In other words, this application employs Distributed Control System (DCS) based on MMC technology, distributing core control functions across multiple independent control units. Each control unit leverages its independent computing and data processing capabilities to achieve real-time monitoring and control of complex systems, and communicates and coordinates via a network. Since distributed control is implemented through multiple levels, with subsystems forming a level and corresponding subsystems enabling the corresponding functions of the control system, this architecture gives the DCS high reliability, flexibility, and scalability. This greatly aligns with the design philosophy of MMC technology for handling distributed control and centralized management. The DCS can effectively address large-scale, complex, and distributed control needs, achieving integrated control by combining the advantages of real-time monitoring, direct digital control, and multi-machine control.

[0064] In the description of this application, it should be noted that the terms "inner" and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0065] It should also be noted that, unless otherwise explicitly specified and limited, the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0066] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An energy storage system, characterized in that, include: Multiple energy storage units connected in series; Multiple control unit groups, one control unit group corresponds to one energy storage unit, the acquisition interface of the control unit group is connected to the acquisition interface of its corresponding energy storage unit, and the control interface of the control unit group is connected to the control interface of its corresponding energy storage unit. The processor has a first sampling communication interface connected to the second sampling communication interface of each control unit group, and a first control communication interface connected to the second control communication interface of each control unit group.

2. The energy storage system according to claim 1, characterized in that, Each control unit group includes a monitoring control unit and an operation control unit. Wherein, the acquisition interface of the monitoring and control unit serves as the acquisition interface of the control unit group, and the control interface of the operation control unit serves as the control interface of the control unit group. The processor is configured to: acquire the operating information of each energy storage unit through the monitoring and control unit, and control the AC side voltage status of each energy storage unit through the operating control unit.

3. The energy storage system according to claim 2, characterized in that, The processor's first sampling communication interface is connected to the second sampling communication interface of each monitoring and control unit, and the processor's first control communication interface is connected to the second control communication interface of each operating control unit. The monitoring and control unit is configured to send the collected operating information of the energy storage unit to the processor. The operation control unit is configured to control the AC side voltage state of the energy storage unit according to the control signal sent by the processor's first control communication interface for the energy storage unit.

4. The energy storage system according to claim 2, characterized in that, The monitoring and control unit also includes a first monitoring interface and a second monitoring interface. The first monitoring interface is connected between the control interface of the operating control unit and the control interface of its corresponding energy storage unit, and the second monitoring interface is connected between the first control communication interface of the processor and the second control communication interface of its corresponding control unit group. The monitoring and control unit is configured to determine the operating status of the operation control unit based on the signal data received by the first monitoring interface and the second monitoring interface respectively.

5. The energy storage system according to claim 4, characterized in that, Also includes: Multiple branch control switches, one branch control switch is correspondingly set on one energy storage branch, the energy storage branch is the branch where an energy storage unit and its corresponding control unit group are located; The monitoring and control unit is configured to control the operation of the branch control switch according to the operating status of the operation control unit, so as to control whether the energy storage branch is connected to the energy storage system.

6. The energy storage system according to claim 2, characterized in that, Each energy storage unit also includes: At least one battery cell; A bridge circuit, with at least one battery cell connected to the DC side of the bridge circuit, and the AC side of the bridge circuit serving as the AC side of the energy storage unit. The AC side of the bridge circuit corresponding to each of the multiple energy storage units is connected in sequence. The operation control unit is configured to control the AC side voltage state of the energy storage units by controlling the conduction state of the bridge circuit.

7. The energy storage system according to claim 6, characterized in that, The bridge circuit includes a first control switch, a second control switch, a third control switch, and a fourth control switch. Wherein, one end of the first control switch is connected to one end of the second control switch, the other end of the first control switch is connected to one end of the third control switch, the other end of the second control switch is connected to one end of the fourth control switch, and the other end of the third control switch is connected to the other end of the fourth control switch.

8. The energy storage system according to claim 7, characterized in that, The connection between the first control switch and the second control switch serves as one end of the DC side of the bridge circuit, and the connection between the third control switch and the fourth control switch serves as the other end of the DC side of the bridge circuit. The connection between the first control switch and the third control switch, and the connection between the second control switch and the fourth control switch, serve as the AC side of the bridge circuit.

9. The energy storage system according to claim 3, characterized in that, Also includes: A first isolation circuit, one end of which is connected to the processor's first synchronization interface; Multiple second isolation circuits are provided, with each second isolation circuit corresponding to one operation control unit. One end of each second isolation circuit is connected to the other end of the first isolation circuit, and the other end of each second isolation circuit is connected to the second synchronization interface of its corresponding operation control unit, so that the second synchronization interface of each operation control unit receives the synchronization signal sent by the first synchronization interface.

10. The energy storage system according to any one of claims 1 to 9, characterized in that, Also includes: The first power interface and the second power interface are used to connect to an external power source or external electrical equipment. The first power interface is led out from the AC side of the first energy storage unit of the plurality of energy storage units, and the second power interface is led out from the AC side of the last energy storage unit of the plurality of energy storage units.

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