Control method and device of energy storage system, energy storage system and readable storage medium

Abstract

The invention discloses a control method and device of an energy storage system, the energy storage system and a readable storage medium, and relates to the technical field of energy storage systems.The method comprises the steps that a first switch and a third switch are controlled to be switched on in response to a power-on instruction, the battery pack is electrically connected with the first capacitor through the first switch and the pre-charging circuit so as to charge the first capacitor; and under the condition that the electrical parameter of the first capacitor meets a preset power-on requirement, the second switch is controlled to be switched on, and the third switch is controlled to be switched off, so that the battery pack is electrically connected with the first capacitor through the first switch and the second switch, and the energy storage system enters a power-on state. According to the invention, the electrical design of the internal loop of the battery pack control system of the energy storage system is optimized, the safe operation performance of the energy storage system is improved, and the integration cost of the energy storage system is reduced.

Description

Technical Field

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

[0002] At present, in the related technologies of integrated energy storage systems, in order to avoid the impact current generated by the instantaneous conduction of the DC bus capacitor at the moment of power-on of the integrated energy storage system, a small current pre-charge contactor and pre-charge resistor are connected in parallel to the contactor of the main circuit inside the battery control system. However, this processing method not only increases the design difficulty of the battery control system structure, but also increases the heat inside the battery control system, and also increases the design cost, making the DC side control system complex. Summary of the invention

[0003] The purpose of the present application is to solve at least one of the technical problems existing in the prior art, and to provide a control method, device, energy storage system and readable storage medium for an energy storage system, aiming to optimize the electrical design of the internal circuit of the battery pack control system of the energy storage system, while improving the safe operation performance of the energy storage system and reducing the cost of energy storage system integration.

[0004] In a first aspect, an embodiment of the present application provides a control method for an energy storage system, wherein the energy storage system includes a battery pack, a battery pack control system, and a power conversion system connected in sequence, wherein the battery pack control system includes a first switch, and the power conversion system includes a pre-charging circuit, a second switch, and a first capacitor, wherein the pre-charging circuit is connected in parallel with the second switch, and the pre-charging circuit includes a third switch and a first resistor connected in series, wherein one end of the second switch and one end of the pre-charging circuit are connected to the first capacitor, and the other end of the second switch and the other end of the pre-charging circuit are connected to the battery pack control system; The control method comprises: In response to a power-on instruction, controlling the first switch and the third switch to close, so that the battery pack is electrically connected to the first capacitor through the first switch and the pre-charging circuit, and the first capacitor is charged; When the electrical parameters of the first capacitor meet the preset power-on requirements, the second switch is controlled to be closed and the third switch is controlled to be opened, so that the battery pack is electrically connected to the first capacitor through the first switch and the second switch, and the energy storage system enters the power-on state.

[0005] According to the technical solution of the embodiment of the present application, at least the following beneficial effects are achieved: the battery pack control system is connected to the battery pack, and the battery pack control system is also the high-voltage control box on the DC side of the energy storage system; the power conversion system is used to convert DC power into AC power output, and the power conversion system includes a pre-charging circuit, which is connected in parallel with the second switch. When the third switch of the pre-charging circuit is closed, the battery pack is electrically connected to the first capacitor through the first switch and the pre-charging circuit. At this time, the first capacitor is charged, and then, when the electrical parameters of the first capacitor meet the preset power-on requirements, for example, when the voltage across the first capacitor meets the preset requirements, the second switch is controlled to be closed and the third switch is controlled to be closed. The three switches are disconnected so that the battery pack is electrically connected to the first capacitor through the first switch and the second switch. At this time, since the previous pre-charging circuit charges the first capacitor when it is electrically connected to the first capacitor, the instantaneous impact current when the second switch is closed is greatly reduced, and since no pre-charging circuit is provided in the high-voltage control box on the DC side of the energy storage system, the heat generation of the high-voltage control box is reduced, the structural design of the high-voltage control box is optimized, the integration efficiency of the energy storage system is improved, and the safe operation of the energy storage system is guaranteed; in addition, when the energy storage system has multiple battery packs, there is no need to add additional pre-charging circuits in the high-voltage control boxes of the multiple battery packs, thereby reducing the cost of integrating the energy storage system.

[0006] According to some embodiments of the present application, in response to the power-on instruction, controlling the first switch and the third switch to close includes: In response to a power-on instruction, the switch state of the second switch is acquired, and when the second switch is in an open state, the first switch and the third switch are controlled to be closed.

[0007] According to some embodiments of the present application, the battery pack control system further includes a fourth switch; The step of acquiring the switch state of the second switch in response to the power-on instruction, and controlling the first switch and the third switch to close when the second switch is in an open state, comprises: In response to a power-on instruction, controlling the fourth switch to close; The switch state of the second switch is acquired, and when the second switch is in an open state, the first switch and the third switch are controlled to be closed.

[0008] According to some embodiments of the present application, controlling the first switch and the third switch to be closed includes: The third switch is controlled to be closed, and then the first switch is controlled to be closed.

[0009] According to some embodiments of the present application, the first switch and the third switch are contactors; and the second switch and the fourth switch are isolating switches.

[0010] According to some embodiments of the present application, when the electrical parameters of the first capacitor meet the preset power-on requirements, controlling the second switch to close and controlling the third switch to open includes: When the electrical parameters of the first capacitor meet the preset power-on requirements, the second switch is controlled to be closed, and the third switch is controlled to be opened.

[0011] According to some embodiments of the present application, the preset power-on requirement includes a requirement for the voltage across the first capacitor.

[0012] According to some embodiments of the present application, the energy storage system includes a plurality of battery packs connected in sequence and a plurality of battery pack control systems corresponding to each battery pack.

[0013] In a second aspect, an embodiment of the present application provides an operation control device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the control method described in the first aspect above.

[0014] In a third aspect, an embodiment of the present application provides an energy storage system, comprising the operation control device of the second aspect described above.

[0015] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium storing computer-executable instructions, wherein the computer-executable instructions are used to enable a computer to execute the control method of the first aspect as described above.

[0016] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide further understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0018] The present application is further described below with reference to the accompanying drawings and embodiments; Figure 1 is a circuit diagram of an energy storage system provided by an embodiment of the present application; Figure 2 is a flow chart of a control method provided by an embodiment of the present application; Figure 3 is a flow chart of a control method provided by another embodiment of the present application; Figure 4is a flow chart of a control method provided by another embodiment of the present application; Figure 5 is a flow chart of a control method provided by another embodiment of the present application; Figure 6 It is a schematic diagram of an operation control device for executing a control method provided in one embodiment of the present application. DETAILED DESCRIPTION

[0019] This section will describe in detail the specific embodiments of the present application. The preferred embodiments of the present application are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present application, but it cannot be understood as a limitation on the scope of protection of the present application.

[0020] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do 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 should not be understood as a limitation on the present application.

[0021] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0022] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0023] The following further describes various embodiments of the control method of the energy storage system of the present application in conjunction with the accompanying drawings.

[0024] like Figure 1 As shown, Figure 1 This is a circuit diagram of an energy storage system provided by an embodiment of the present application. The energy storage system includes a battery pack, a battery pack control system and a power conversion system connected in sequence. The battery pack control system includes a first switch, and the power conversion system includes a pre-charging circuit, a second switch and a first capacitor. The pre-charging circuit is connected in parallel with the second switch, and the pre-charging circuit includes a third switch and a first resistor connected in series. One end of the second switch and one end of the pre-charging circuit are connected to the first capacitor, and the other end of the second switch and the other end of the pre-charging circuit are connected to the battery pack control system.

[0025] It can be understood that the energy storage system provided in the embodiment of the present application includes a battery pack, a battery pack control system and a power conversion system connected in sequence, wherein the reference Figure 1 , the battery pack is Figure 1 The battery string in the energy storage system is the core of the battery pack, which is used to store and release electrical energy. The battery pack includes multiple battery cells, which can be lithium-ion batteries, lead-acid batteries, sodium-sulfur batteries, flow batteries, etc. The appropriate battery type can be selected according to the application scenario and requirements; the battery pack control system refers to Figure 1 The control box in the energy storage system is the high-voltage control box on the DC side of the energy storage system. The battery pack control system is used to collect data such as the voltage and current of the battery pack, as well as control and detect the contactor in the high-voltage circuit and provide corresponding protection functions. The battery pack control system may include electrical components such as pre-charge relays, fuses, shunts, pre-charge resistors, etc. The power conversion system refers to Figure 1 In the PCS, the power conversion system is used to convert the DC power stored in the battery pack into AC power for use by the load or for transmission to the power grid, or to convert the AC power of the power grid into DC power to charge the battery pack. The power conversion system may include power electronic devices such as inverters, transformers, and filters.

[0026] In addition, in some embodiments, the energy storage system may also include a monitoring system, a heat dissipation system, a protection device, a communication system, an energy management system (EMS), a rectification and filtering system, etc.

[0027] In this embodiment, the battery control system includes a first switch, and the power conversion system includes a second switch. The first switch and the second switch may be electrical switch devices of the type of a DC contactor, a relay, a circuit breaker, a gas-insulated switch, an isolating switch, etc. The first switch is used to control the closing and opening of the high-voltage main circuit of the battery control system. The high-voltage main circuit of the battery control system may be a circuit from the connection point between the battery pack and the battery control system to the first switch, and then to the connection point between the battery control system and the power conversion system. The power conversion system includes a pre-charging circuit, a second switch and a first capacitor, wherein the pre-charging circuit includes a third switch and a first resistor connected in series, and the pre-charging circuit is connected in parallel with the second switch, one end of the second switch and one end of the pre-charging circuit are connected to the first capacitor, and the other end of the second switch and the other end of the pre-charging circuit are connected to the battery pack control system; That is to say, the power conversion system includes a second switch and a third switch in different circuits, and the second switch and the third switch respectively control the closing and opening of different circuits in the power conversion system, wherein the circuits in the power conversion system may include a main circuit and a pre-charging circuit, and the main circuit of the power conversion system may be a circuit from the connection point between the battery pack control system and the power conversion system to the second switch, and then to the first capacitor, and the pre-charging circuit may be a circuit from the connection point between the battery pack control system and the power conversion system to the pre-charging circuit, and then to the first capacitor, the second switch is used to control the on and off of the main circuit of the power conversion system, and the third switch is used to control the on and off of the pre-charging circuit of the power conversion system.

[0028] It can be foreseen that the battery pack control system is not provided with a pre-charging circuit including a pre-charging relay and a pre-charging resistor, but a pre-charging circuit is provided in the power conversion system. Based on this, since the pre-charging circuit is not provided in the high-voltage control box on the DC side of the energy storage system, the heat generation of the high-voltage control box is reduced, the structural design of the high-voltage control box is optimized, the integration efficiency of the energy storage system is improved, and the safe operation of the energy storage system is guaranteed; in addition, when the energy storage system has multiple battery packs, there is no need to add additional pre-charging circuits in the high-voltage control boxes of the multiple battery packs, thereby reducing the cost of energy storage system integration.

[0029] In addition, in some embodiments, a pre-charging circuit is provided in both the battery pack control system and the power conversion system. In this case, the pre-charging function is still mainly realized by the pre-charging circuit of the battery pack control system, and the pre-charging circuit provided in the power conversion system is used as a secondary pre-charging to enhance the operating safety of the energy storage system. That is to say, when the energy storage system includes multiple battery packs, the multiple battery pack control systems corresponding to the multiple battery packs have multiple pre-charging circuits, and the pre-charging circuit is also provided in the power conversion system, which will greatly increase the cost. Therefore, it is chosen not to provide a pre-charging circuit including a pre-charging relay and a pre-charging resistor in the battery pack control system, thereby optimizing the structural design of the high-voltage control box and reducing the cost of energy storage system integration.

[0030] like Figure 2 As shown, Figure 2 It is a flowchart of a control method provided by an embodiment of the present application. The control method may include but is not limited to step S110 and step S120.

[0031] Step S110, in response to the power-on instruction, controlling the first switch and the third switch to close, so that the battery pack is electrically connected to the first capacitor through the first switch and the pre-charging circuit, and the first capacitor is charged; Step S120: When the electrical parameters of the first capacitor meet the preset power-on requirements, the second switch is controlled to be closed and the third switch is controlled to be opened, so that the battery pack is electrically connected to the first capacitor through the first switch and the second switch, and the energy storage system enters the power-on state.

[0032] It can be understood that since the battery pack control system does not have a pre-charging circuit including a pre-charging relay and a pre-charging resistor, but a pre-charging circuit is provided in the power conversion system, the pre-charging circuit provided in the power conversion system can be controlled accordingly. Through the pre-charging circuit provided in the power conversion system, excessive inrush current can be avoided when the main power supply is turned on, thereby protecting the electronic components and switching devices in the system.

[0033] It is understandable that the power-on instruction refers to a start or start signal received by the energy storage system, which is used to instruct the energy storage system to start powering on and running. It is understandable that before receiving the power-on instruction, the energy storage system should be in a power-off state, that is, at least one switch of the energy storage system is in a disconnected state, so as to facilitate maintenance and other operations on the energy storage system. In some embodiments, before receiving the power-on instruction, the first switch of the battery pack control system may be in a disconnected state, the second switch and the third switch of the power conversion system may be in a disconnected state, or the first switch, the second switch, and the third switch may all be in a disconnected state.

[0034] In this embodiment, before receiving the power-on command, the first switch, the second switch, and the third switch are all in the disconnected state. After receiving the power-on command, in response to the power-on command, the first switch of the battery pack control system and the third switch of the power conversion system are controlled to close. In this way, when the first switch of the battery pack control system is closed, the battery pack control system is electrically connected to the battery pack, and then when the third switch of the power conversion system is closed, the battery pack, the battery pack control system and the pre-charging circuit of the power conversion system are electrically connected. That is, the battery pack can be electrically connected to the first capacitor through the first switch and the pre-charging circuit, so that the battery pack charges the first capacitor.

[0035] It is understandable that the first switch and the third switch can be electrical switching devices of the type of DC contactor, relay, circuit breaker, gas insulated switch, disconnector, etc. Among them, the circuit breaker has a short-circuit protection function and can cut off the fault current, while the disconnector is mainly used to isolate the power supply, has no arc extinguishing ability, and cannot be operated with load. The DC contactor is suitable for frequent switching, etc. When the first switch and the third switch choose to use different types of switches, there may be different switching sequences or switch control methods. For example, the circuit breaker has overcurrent / short-circuit protection function and is suitable as the main protection switch, but the operating frequency is low; the contactor is suitable for frequent switching (such as PCS charging and discharging control) and needs to be protected by a fuse or circuit breaker; the disconnector is only used for visible isolation points and needs to be used in conjunction with the circuit breaker; the gas insulated switch has a strong arc extinguishing ability and is suitable for high-voltage closed environments, but the maintenance is complex; In addition, the selection of switching sequence and control method must also be considered. If the switching sequence is incorrect, arc damage to the equipment may occur. For example, disconnecting the isolating switch of the battery control system with load first may cause arcing and burn the contacts. Therefore, the selection of switching sequence and control method needs to be determined according to specific application requirements, voltage levels, current sizes, and protection requirements. For example, relays and contactors can achieve automatic timing control through PLC programming, while isolating switches usually require manual operation or remote electric control. Arcs are easily generated when contactors disconnect DC loads, and arc extinguishing devices or series circuit breakers need to be configured. Before operating the isolating switch, the circuit zero current must be confirmed by a current sensor.

[0036] For example, since the circuit breaker has short-circuit protection capability and is suitable as main circuit protection, and the contactor is suitable for frequent operation but needs to avoid breaking large currents under load, the first switch uses a circuit breaker and the third switch uses a DC contactor. At this time, the first switch circuit breaker can be closed first to ensure the main circuit's conductivity, and then the third switch DC contactor can be closed to avoid the contactor from being subjected to impact current; since the isolating switch has no arc extinguishing capability and must rely on the circuit breaker to cut off the load current, therefore, the first switch uses an isolating switch and when the third switch uses a circuit breaker, the third switch can be closed first to ensure that the circuit has arc extinguishing capability and then the first switch can be closed; since the isolating switch is mainly used to isolate the power supply and has no arc extinguishing capability and cannot be operated under load, therefore, the first switch uses an isolating switch and when the third switch uses a contactor, the first switch can be closed first and then the third switch.

[0037] It is understandable that the voltage of the energy storage system, the capacitance value of the first capacitor, and the required pre-charging time are usually defined at the beginning of the design. Therefore, the first resistor with a suitable resistance value can be selected through parameters such as the voltage of the energy storage system, the capacitance value of the first capacitor, the pre-charging time, and the charging voltage value reached at both ends of the capacitor. For example, after the pre-charging time, the main positive relay is closed, and the charging voltage value reached at both ends of the capacitor is required to reach a preset range of the power supply voltage, or after the pre-charging time, the main positive relay is closed, and the difference between the charging voltage value reached at both ends of the capacitor and the power supply voltage is required to be within a preset range. In addition, since the main function of the first resistor is to limit the charging current and prevent excessive current shocks during the charging process, the size of the resistor needs to be selected according to the maximum current that the system can withstand; the first resistor will consume a certain amount of power during the charging process, so the size of the first resistor needs to minimize the power loss as much as possible under the premise of ensuring that the charging current does not exceed the system's tolerance; since the pre-charging resistor will generate heat, its heat dissipation capacity needs to be considered; that is, the selection of the first resistor of the pre-charging circuit needs to consider multiple factors, including current limitation, power loss, thermal design, etc.

[0038] It is understandable that before the energy storage system is powered on, the first capacitor may be in an uncharged state, that is, the voltage across the first capacitor is zero, and no charge is stored inside. In this state, the charge of the first capacitor is zero and the electric field strength is also zero; and after the battery pack is electrically connected to the first capacitor through the first switch and the pre-charging circuit, the first capacitor is charged to a predetermined voltage level. The pre-charged first capacitor is in a partially charged state, a certain amount of charge is stored inside the capacitor, and the electric field strength increases accordingly, thereby reducing the impact current when the system is powered on and protecting other components in the system from damage.

[0039] Therefore, when the electrical parameters of the first capacitor meet the preset power-on requirements, for example, the charging voltage value across the first capacitor reaches the preset range, the second switch is controlled to close and the third switch is controlled to open, and when the second switch of the battery pack control system is closed, the battery pack control system is electrically connected to the battery pack, and then when the second switch of the power conversion system is closed, the battery pack, the battery pack control system and the main circuit of the power conversion system are electrically connected, that is, the battery pack can be electrically connected to the first capacitor through the first switch and the second switch, thereby enabling the energy storage system to enter a power-on state.

[0040] like Figure 3 As shown, Figure 3 It is a flowchart of a control method provided by another embodiment of the present application; regarding the above-mentioned step S110, it may include but is not limited to step S210.

[0041] Step S210: In response to the power-on instruction, the switch state of the second switch is acquired, and when the second switch is in the open state, the first switch and the third switch are controlled to be closed.

[0042] In this embodiment, the second switch may be an isolating switch.

[0043] It can be understood that the second switch is used to control the on-off of the main circuit of the power conversion system, that is, from the connection point between the battery pack control system and the power conversion system to the second switch, and then to the circuit of the first capacitor. The third switch is used to control the on-off of the pre-charging circuit of the power conversion system, that is, from the connection point between the battery pack control system and the power conversion system to the pre-charging circuit, and then to the circuit of the first capacitor. Before the energy storage system is powered on, the first capacitor needs to be charged first. When the second switch is closed, the main circuit and the pre-charging circuit in the power conversion system are both in the on state. At this time, the purpose of charging the first capacitor first cannot be achieved, and the safe operation of the energy storage system cannot be guaranteed. That is to say, before completing the charging of the first capacitor, it is necessary to ensure that the second switch is in the disconnected state.

[0044] Therefore, after responding to the power-on command, it is possible to first determine whether the second switch remains in the off state, obtain the switch state of the second switch, and control the first switch and the third switch to close when the second switch is in the off state; when the second switch is in the closed state, it is necessary to control the second switch to open or remind the staff to manually open the second switch.

[0045] In a control method provided in another embodiment of the present application, the battery pack control system further includes a fourth switch; Figure 4 As shown, Figure 4 It is a flowchart of a control method provided by another embodiment of the present application; regarding the above-mentioned step S210, it may include but is not limited to step S310 and step S410.

[0046] Step S310, in response to a power-on instruction, controlling the fourth switch to close; Step S410: Acquire the switch state of the second switch, and when the second switch is in the open state, control the first switch and the third switch to be closed.

[0047] It is understandable that a switch in a circuit can usually only perform one function, for example, only for turning the circuit on and off or only for isolating the power supply. When relying on only one switch, safety may not be ensured in all cases, especially in the event of failure or maintenance. Therefore, in addition to the first switch, the battery pack control system also includes a fourth switch. Through the complementary effects of the first switch and the fourth switch, double protection can be provided to reduce the risk of failure. Even if one switch fails, the other switch can still ensure the safe isolation or normal operation of the circuit. Moreover, in different operating modes, the first switch and the fourth switch can be used flexibly to meet different needs. For example, when the first switch is a contactor and the fourth switch is an isolating switch, the first switch can be used to frequently connect and disconnect the circuit, which is suitable for control in daily operation, and can be safely disconnected under load to prevent arc damage; the fourth switch is mainly used to isolate the high-voltage power supply to ensure that the circuit is completely disconnected during maintenance or overhaul, and provide a visible disconnection point to facilitate confirmation of the circuit status and enhance safety.

[0048] In this embodiment, the fourth switch can be an isolating switch to ensure that the circuit of the energy storage system is completely disconnected during maintenance or overhaul. Therefore, in order to ensure that the battery pack can be electrically connected to the first capacitor through the first switch and the pre-charging circuit to charge the first capacitor, in response to the power-on instruction, the fourth switch can be controlled to close first, and when the fourth switch is closed, the switching state of the second switch is obtained, so that when the second switch is in the open state, the first switch and the third switch are controlled to close.

[0049] In a control method provided in another embodiment of the present application, the above-mentioned step S110, step S210 and step S410 may include but are not limited to step S510.

[0050] Step S510, controlling the third switch to close, and then controlling the first switch to close.

[0051] It can be understood that the third switch is the switch of the pre-charging circuit of the power conversion system. The switch of the pre-charging circuit can usually use a contactor or a relay. The first switch is the switch that controls the on-off of the circuit of the battery pack control system. Therefore, the first switch can also use a contactor or a relay.

[0052] In this embodiment, the third switch is first controlled to close, so that a pre-charging circuit in the power conversion system can be formed in advance, that is, a circuit from the connection point between the battery pack control system and the power conversion system to the pre-charging circuit and then to the first capacitor. Subsequently, the first switch is controlled to close. When the first switch is closed, since the pre-charging circuit has been formed, the battery pack can quickly charge the first capacitor through the pre-charging circuit, thereby quickly making the voltage across the first capacitor reach a predetermined level.

[0053] In a control method provided in another embodiment of the present application, the first switch and the third switch are contactors; and the second switch and the fourth switch are isolating switches.

[0054] In this embodiment, the first switch and the third switch are contactors, and the second switch and the fourth switch are isolating switches, that is, the battery pack control system includes a contactor and an isolating switch, and the power conversion system includes an isolating switch and a contactor on a pre-charging circuit. The isolating switch is mainly used to isolate the power supply, has no arc extinguishing capability, and cannot be operated under load. The DC contactor is suitable for frequent switching; based on this, the closing sequence of the first switch, the second switch, the third switch and the fourth switch can be: first close the isolating switch of the battery pack control system, and then, when the isolating switch of the power conversion system is disconnected, close the contactor on the pre-charging circuit of the power conversion system to form a pre-charging circuit in the power conversion system, and then close the contactor of the battery pack control system so that the battery pack is electrically connected to the first capacitor through the first switch and the pre-charging circuit to charge the first capacitor. Subsequently, when the electrical parameters of the first capacitor meet the preset power-on requirements, control the isolating switch of the power conversion system and then control the contactor on the pre-charging circuit of the power conversion system to disconnect, so that the battery pack is electrically connected to the first capacitor through the first switch and the second switch, and the energy storage system enters the power-on state.

[0055] like Figure 5 As shown, Figure 5 It is a flow chart of a control method provided by another embodiment of the present application; regarding the above-mentioned step S120, it may include but is not limited to step S220.

[0056] Step S220: When the electrical parameters of the first capacitor meet the preset power-on requirements, the second switch is controlled to be closed, and the third switch is controlled to be opened.

[0057] It is understandable that in the power conversion system of the energy storage system, the pre-charging circuit is used to pre-charge the first capacitor (DC bus capacitor) through a current limiting resistor to avoid excessive surge current when directly connected to the battery pack control system. After the pre-charging is completed, that is, after the first capacitor is charged so that the electrical parameters of the first capacitor meet the preset power-on requirements, when switching to the main circuit of the power conversion system, the second switch of the main circuit is closed first, and then the third switch of the pre-charging circuit is opened; Because after the main circuit is closed, the current will naturally transfer to the low-impedance main circuit path. At this time, the current in the third switch has been greatly reduced or even close to zero. If the third switch is disconnected first and the second switch of the main circuit has not been closed, the energy storage system will lose the current path, causing the first capacitor to discharge or the voltage across the first capacitor to suddenly change, causing equipment damage or protection action; and if there is a large current when the third switch is disconnected, an arc may be generated, shortening the life or even damaging the equipment. After the main circuit is closed, the current is transferred to the main circuit, and the third switch only needs to disconnect a small current, which can significantly reduce the risk of arc. If the order is reversed, the third switch may be disconnected at full load current, causing serious arc; In addition, if the third switch is disconnected first and then the second switch of the main circuit is closed, the voltage of the first capacitor may drop due to a brief power outage. At this time, if the second switch of the main circuit is closed, the difference between the DC bus voltage and the first capacitor voltage may trigger a surge current again. Since the pre-charging circuit has been disconnected, the current limiting protection is lost and the main circuit components may be damaged. Moreover, if the second switch of the main circuit is an isolating switch, since the isolating switch needs to operate in a no-current state, if the third switch is disconnected first and the main circuit has not yet been closed, the isolating switch may need to be closed under load, resulting in contact erosion or failure.

[0058] In a control method provided in another embodiment of the present application, the preset power-on requirement includes a requirement for the voltage across the first capacitor.

[0059] It can be understood that the pre-charging circuit is used to pre-charge the first capacitor (DC bus capacitor) through a current limiting resistor so that the electrical parameters of the first capacitor meet the preset power-on requirements to avoid excessive surge current when directly connected to the battery pack control system. In this embodiment, the preset power-on requirements include requirements for the voltage across the first capacitor. This is because if the difference between the bus voltage and the battery voltage is too large, that is, the pre-charging is not completed, directly closing the isolating switch of the main circuit will cause an instantaneous large current shock; illustratively, the preset power-on requirements include the voltage across the first capacitor reaching 90% to 95% of the rated voltage of the battery pack. In the pre-charging process, when the first capacitor voltage is charged to close to 90% to 95% of the rated voltage of the battery pack through the first resistor, it indicates that the electrical parameters of the first capacitor have met the preset power-on requirements, and the second switch can be controlled to close and the third switch can be controlled to open.

[0060] In some embodiments, the preset power-on requirement may also include a charging current requirement. Exemplarily, the preset power-on requirement includes a charging current lower than 1% to 5% of the rated current of the battery pack. During the pre-charging process, when the charging current is lower than 1% to 5% of the rated current of the battery pack, it indicates that the electrical parameters of the first capacitor have met the preset power-on requirement, and the second switch can be controlled to close and the third switch can be controlled to open.

[0061] In a control method provided in another embodiment of the present application, an energy storage system includes a plurality of battery packs connected in sequence and a plurality of battery pack control systems corresponding to each battery pack.

[0062] It can be understood that the energy storage system includes a group of battery packs connected in sequence, a group of battery pack control systems and a group of power conversion systems, and can also include multiple groups of battery packs connected in sequence, multiple groups of battery pack control systems corresponding to each group of battery packs, and a group of power conversion systems. That is to say, multiple groups of battery pack control systems are connected to a group of power conversion systems, and the power conversion function and control function of the multiple groups of battery packs are realized through a group of power conversion systems. In addition, through a pre-charging circuit of a group of power conversion systems, the impact current at the moment of power-on of the energy storage system with multiple groups of battery packs is reduced.

[0063] refer to Figure 1 The energy storage system may include multiple battery packs and multiple battery pack control systems corresponding to each battery pack. The battery pack refers to Figure 1 The battery string in the battery pack control system refers to Figure 1 The control box in the power conversion system refers to Figure 1In the PCS, each battery control system includes positive and negative incoming power connector sockets BAT+ and BAT- connected to the battery string, fuses FU1 and FU2, disconnector QS1, shunt FL1, positive and negative contactors KM1 and KM2, the first switch refers to the positive and negative contactors KM1 and KM2, and the fourth switch refers to the disconnector QS1; Each power conversion system includes a PCS DC side power socket DC+, DC- connector, a fuse FU3, an isolating switch QS2, positive and negative pre-charging contactors KM3, KM4, positive and negative pre-charging resistors R1, R2, DC bus capacitors C1, C2, a rectifier and filter module, the second switch refers to the isolating switch QS2, the third switch refers to the positive and negative pre-charging contactors KM3, KM4, the first capacitor refers to the DC bus capacitors C1, C2, and the first resistor refers to the positive and negative pre-charging resistors R1, R2; In the battery pack control system, the positive and negative incoming power connector sockets BAT+ and BAT- are connected to one end of the fuses FU1 and FU2 respectively, and the other ends of the fuses FU1 and FU2 are connected to the incoming end of the disconnector QS1 respectively. The positive outgoing side of the disconnector QS1 is connected to the positive contactor KM1 through a copper busbar, and the negative pole of the disconnector QS1 is connected to one end of the shunt FL1 through a copper busbar. The other end of the shunt FL1 is connected to one end of the negative contactor KM2 of the high-voltage circuit. The other ends of the positive and negative contactors KM1 and KM2 are connected to the PCS DC side power sockets DC+ and DC- connectors respectively; In the power conversion system, the PCS DC side power socket DC+ is connected to one end of the fuse FU3, the other end of the fuse FU3 is respectively connected to one end of the positive pre-charging contactor KM3 and the positive inlet terminal of the isolating switch QS2, the other end of the positive pre-charging contactor KM3 is connected to one end of the positive pre-charging resistor R1, the other end of the positive pre-charging resistor R1 and the positive outlet side of the isolating switch QS2 are both connected to one end of the DC bus capacitor C1, the other end of the DC bus capacitor C1 is connected to one end of the DC bus capacitor C2, the other end of the DC bus capacitor C2 is respectively connected to one end of the negative pre-charging resistor R2 and the negative outlet side of the isolating switch QS2, the other end of the negative pre-charging resistor R2 is connected to one end of the negative pre-charging contactor KM4, and the other end of the negative pre-charging contactor KM4 is respectively connected to the negative inlet terminal of the isolating switch QS2 and the PCS DC side power socket DC-.

[0064] Based on the control methods of the above-mentioned embodiments, various embodiments of the operation control device, energy storage system, and computer-readable storage medium of the present application are respectively proposed below.

[0065] like Figure 6 As shown, Figure 6600 is a schematic diagram of an operation control device for executing a control method provided by an embodiment of the present application. The operation control device 600 implemented in the present application includes: a processor 620, a memory 610, and a computer program stored in the memory 610 and executable on the processor 620, wherein: Figure 6 In the figure, a processor 620 and a memory 610 are taken as an example.

[0066] The processor 620 and the memory 610 may be connected via a bus or other means. Figure 6 The example of connecting through bus is taken in the following.

[0067] The memory 610, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer executable programs. In addition, the memory 610 may include a high-speed random access memory, and may also include a non-transitory memory, such as at least one disk storage device, a flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 610 optionally includes a memory 610 remotely arranged relative to the processor 620, and these remote memories 610 can be connected to the operation control device 600 via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0068] Those skilled in the art will understand that Figure 6 The device structure shown in the figure does not constitute a limitation on the operation control device 600, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0069] exist Figure 6 In the operation control device 600 shown, the processor 620 can be used to call the control program stored in the memory 610 to implement the above control method. Specifically, the non-transient software program and instructions required to implement the control method of the above embodiment are stored in the memory 610, and when executed by the processor 620, the control method of the above embodiment is executed.

[0070] It is worth noting that since the operation control device 600 of the embodiment of the present application can execute the control method of any of the above-mentioned embodiments, the specific implementation manner and technical effects of the operation control device 600 of the embodiment of the present application can refer to the specific implementation manner and technical effects of the control method of any of the above-mentioned embodiments.

[0071] In addition, an embodiment of the present application further provides an energy storage system, which includes the operation control device of the above embodiment.

[0072] It is worth noting that since the energy storage system of the embodiment of the present application includes the operation control device of the above embodiment, and the operation control device of the above embodiment can execute the control method of any of the above embodiments, the specific implementation methods and technical effects of the energy storage system of the embodiment of the present application can refer to the specific implementation methods and technical effects of the control method of any of the above embodiments.

[0073] In addition, an embodiment of the present application further provides a computer-readable storage medium, which stores computer-executable instructions, and the computer-executable instructions are used to execute the above-described control method. Figures 2 to 5 The method steps in .

[0074] It is worth noting that since the computer-readable storage medium of the embodiments of the present application can execute the control method of any of the above embodiments, the specific implementation methods and technical effects of the computer-readable storage medium of the embodiments of the present application can refer to the specific implementation methods and technical effects of the control method of any of the above embodiments.

[0075] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed methods above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium or a non-transitory medium and a communication medium or a temporary medium. As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disk DVD or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0076] In several embodiments provided in the present application, it should be understood that the disclosed systems, apparatuses and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of apparatuses or units, which can be electrical, mechanical or other forms. The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0077] It should also be understood that the various implementations provided in the embodiments of the present application can be combined arbitrarily to achieve different technical effects.

[0078] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present application.

Claims

1. A control method for an energy storage system, characterized in that: The energy storage system comprises a battery pack, a battery pack control system and a power conversion system connected in sequence, the battery pack control system comprises a first switch, the power conversion system comprises a pre-charging circuit, a second switch and a first capacitor, the pre-charging circuit is connected in parallel with the second switch, the pre-charging circuit comprises a third switch and a first resistor connected in series, one end of the second switch and one end of the pre-charging circuit are connected to the first capacitor, and the other end of the second switch and the other end of the pre-charging circuit are connected to the battery pack control system; The control method comprises: In response to a power-on instruction, controlling the first switch and the third switch to close, so that the battery pack is electrically connected to the first capacitor through the first switch and the pre-charging circuit, and the first capacitor is charged; When the electrical parameters of the first capacitor meet the preset power-on requirements, the second switch is controlled to be closed and the third switch is controlled to be opened, so that the battery pack is electrically connected to the first capacitor through the first switch and the second switch, and the energy storage system enters the power-on state.

2. The control method according to claim 1, characterized in that: In response to the power-on instruction, controlling the first switch and the third switch to close includes: In response to a power-on instruction, the switch state of the second switch is acquired, and when the second switch is in an open state, the first switch and the third switch are controlled to be closed.

3. The control method according to claim 2, characterized in that: The battery pack control system further includes a fourth switch; The step of acquiring the switch state of the second switch in response to the power-on instruction, and controlling the first switch and the third switch to close when the second switch is in an open state, comprises: In response to a power-on instruction, controlling the fourth switch to close; The switch state of the second switch is acquired, and when the second switch is in an open state, the first switch and the third switch are controlled to be closed.

4. The control method according to claims 1 to 3, characterized in that: The controlling the first switch and the third switch to be closed includes: The third switch is controlled to be closed, and then the first switch is controlled to be closed.

5. The control method according to claim 3, characterized in that: The first switch and the third switch are contactors; the second switch and the fourth switch are isolating switches.

6. The control method according to claim 1, characterized in that: When the electrical parameter of the first capacitor meets the preset power-on requirement, controlling the second switch to be closed and controlling the third switch to be opened includes: When the electrical parameters of the first capacitor meet the preset power-on requirements, the second switch is controlled to be closed, and the third switch is controlled to be opened.

7. The control method according to claim 1, characterized in that: The preset power-on requirement includes a requirement for the voltage across the first capacitor.

8. The control method according to claim 1, characterized in that: The energy storage system includes a plurality of battery groups connected in sequence and a plurality of battery group control systems corresponding to each battery group.

9. An operation control device, characterized in that: The invention comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the control method according to any one of claims 1 to 8.

10. An energy storage system, characterized in that: Includes the operation control device as described in claim 9.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the control method according to any one of claims 1 to 8.

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