Control circuit and control method of energy storage system

Abstract

The invention provides a control circuit and a control method of an energy storage system, and belongs to the technical field of electrical control. The first end of a switch unit in the control circuit is used for being connected with the positive electrode of an energy storage unit, and the second end of the switch unit is connected with the first end of a first protection unit, the first end of a pre-charging unit and the first end of a secondary power supply unit. The second end of the first protection unit is connected with the second end of the pre-charging unit and the first end of the external equipment, and the third end of the first protection unit is connected with the first end of the control module; the third end of the pre-charging unit is connected with the second end of the control module; the second end of the secondary power supply unit is connected with the third end of the control module, and the third end of the secondary power supply unit is used for connecting the cathode of the energy storage unit and external equipment. According to the invention, the effect of enabling the energy storage unit to seamlessly absorb the redundant generating capacity of the external power supply can be achieved, and black start can be realized through a circuit design which is relatively simple and relatively low in operation and maintenance cost.

Description

Technical Field

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

[0002] With the rapid development of electric power technology, various power systems with energy storage devices have become widely popular. Energy storage devices can effectively adjust the energy of the power system by shaving peaks and filling valleys.

[0003] In the related art, the energy storage system is generally provided with secondary devices such as batteries, over-discharge protection units, over-charge protection units, uninterruptible power supply (UPS) modules, and controllers. The batteries in the energy storage system are directly coupled to the DC bus through the contactors of the protection units. Moreover, when the over-discharge protection or over-charge protection is triggered, the over-discharge protection unit or the over-charge protection unit will trip the contactor to protect the battery. In addition, the controller can also be powered by the UPS module to enable the energy storage system to perform a black start.

[0004] However, when the over-discharge protection is triggered, the solution of the related art will directly control the decoupling of the over-discharge protection battery and the DC bus, making the system unavailable, which in turn makes it impossible to achieve the purpose of seamless absorption when the energy storage unit is required to absorb the excess power generation. In addition, since this solution also requires black start through the UPS module, there are also problems such as complex system design and high operation and maintenance costs. Summary of the invention

[0005] The purpose of the present application is to provide a control circuit and control method for an energy storage system, which can achieve the effect of enabling the energy storage unit to seamlessly absorb the excess power generated by the external power supply, and can also achieve black start with a relatively simple circuit design with low operation and maintenance costs.

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

[0007] In a first aspect of an embodiment of the present application, a control circuit of an energy storage system is provided, the control circuit comprising: a switch unit, a first protection unit, a pre-charging unit, a secondary power supply unit and a control module;

[0008] The first end of the switch unit is used to connect the positive electrode of the energy storage unit, and the second end of the switch unit is respectively connected to the first end of the first protection unit, the first end of the pre-charging unit, and the first end of the secondary power supply unit; the switch unit is used to turn on or off the transmission path of the energy storage unit;

[0009] The second end of the first protection unit is connected to the second end of the pre-charging unit and the first end of the external device respectively, and the third end of the first protection unit is connected to the first end of the control module; the first protection unit is used to turn on or off under the control of the control module to turn on or off the first transmission path of the energy storage unit;

[0010] The third end of the pre-charging unit is connected to the second end of the control module; the pre-charging unit is used to output the electric energy output by the energy storage unit to the external device through the second transmission path when turned on, and to transmit the electric energy input by the external power supply to the energy storage unit through the second transmission path when turned off, and the pre-charging unit is controlled by the control module; the current flowing through the first transmission path is greater than the current flowing through the second transmission path;

[0011] The second end of the secondary power supply unit is connected to the third end of the control module, and the third end of the secondary power supply unit is used to connect the negative electrode of the energy storage unit and the external device; the secondary power supply unit is used to supply power to the control module when the switch unit is turned on;

[0012] The control module is used to control the pre-charging unit to be turned on after power-on, and to control the first protection unit to be turned on after pre-charging is completed.

[0013] Optionally, the pre-charging unit includes a resistor and a switch tube;

[0014] The first end of the resistor is connected to the second end of the switch unit, the second end of the resistor is connected to the first pole of the switch tube, the second pole of the switch tube is connected to the second end of the first protection unit, and the third pole of the switch tube is connected to the second end of the control module;

[0015] The switch tube is used to be turned on or off under the control of the control switch, and is used to output the electric energy output by the energy storage unit to the external device when turned on, and to transmit the electric energy input by the external power supply to the energy storage unit when turned off.

[0016] Optionally, the control circuit further includes: a second protection unit;

[0017] The first end of the second protection unit is connected to the second end of the switch unit, the second end of the second protection unit is connected to the first end of the first protection unit, and the third end of the second protection unit is connected to the fourth end of the control module;

[0018] The second protection unit is used to be turned on or off under the control of the control module to turn on or off the first transmission path of the energy storage unit.

[0019] Optionally, the control circuit further includes: a backup power holding unit;

[0020] The first end of the backup power holding unit is connected to the second end of the switch unit, the second end of the backup power holding unit is connected to the first end of the first protection unit, and the third end of the backup power holding unit is connected to the collection end of the control module;

[0021] The backup power holding unit is used to output the electric energy output by the energy storage unit to the first protection unit, and to prevent the electric energy input by the external power supply from being transmitted to the energy storage unit through the backup power holding unit;

[0022] The control module is further used to collect the voltage of the backup power holding unit, and control the second protection unit to be turned on or off based on the voltage.

[0023] Optionally, the backup power holding unit includes: a diode and a reactor;

[0024] The anode of the diode is connected to the second end of the switch unit, the cathode of the diode is connected to the first end of the reactor, and the second end of the reactor is connected to the first end of the first protection unit;

[0025] The first end and the second end of the reactor are respectively connected to the collection end of the control module.

[0026] Optionally, the control module includes a voltage sampling unit and an execution unit;

[0027] The first end and the second end of the voltage sampling unit are connected to the first end and the second end of the reactor respectively; the voltage sampling unit is used to collect the voltage of the reactor and send the voltage of the reactor to the execution unit;

[0028] The execution unit is used to control the second protection unit to be turned on or off based on the voltage of the reactor, and to control the first protection unit, the pre-charging unit, and the switching unit to be turned on or off.

[0029] Optionally, the sixth end of the control module is also connected to the third end of the switch unit, the seventh end of the control module is also connected to the communication end of the external device, and the eighth end of the control module is also connected to the power supply end of the external device;

[0030] The external device is used to supply power to the control module;

[0031] The control module is further specifically used to control the switch unit to be disconnected when the energy storage unit triggers undervoltage protection, and to receive and respond to a control instruction sent by the external device to control the switch unit to be turned on or off.

[0032] Optionally, the first protection unit includes a first relay; the switch unit includes at least one circuit breaker; and the secondary power supply unit includes a DC-DC converter.

[0033] A second aspect of an embodiment of the present application provides a control method for an energy storage system, which is applied to a control circuit of any energy storage system provided in the first aspect above, wherein the control circuit comprises: a switch unit, a first protection unit, a pre-charging unit, a secondary power supply unit, and a control module; the method comprises:

[0034] In response to the switch unit being turned on, controlling the pre-charging unit to be turned on, so that the energy storage unit pre-charges the external device;

[0035] When confirming that the pre-charging is completed, controlling the first protection unit to be turned on and the pre-charging unit to be turned off, so that the energy storage system is black-started;

[0036] In response to the energy storage unit triggering an over-discharge protection state, controlling the first protection unit to shut down;

[0037] When it is determined that the energy storage unit is in a charging state, the first protection unit is controlled to be turned on to release the over-discharge protection state.

[0038] Optionally, when the control circuit further includes a second protection unit and a backup power holding unit, the method further includes:

[0039] In response to the energy storage unit triggering an overcharge protection state, controlling the second protection unit to be turned off so that the control circuit is in a standby state;

[0040] Detecting the voltage of the backup power holding unit in real time;

[0041] When the voltage of the backup power holding unit meets a preset condition, the second protection unit is controlled to be turned on to release the overcharge protection state; wherein the voltage of the backup power holding unit is used to indicate whether the energy storage unit discharges to an external device.

[0042] The beneficial effects of the embodiments of the present application include:

[0043] A control circuit of an energy storage system provided in an embodiment of the present application is provided by setting a switch unit, a first protection unit, a pre-charging unit, a secondary power supply unit and a control module in the control circuit. The first end of the switch unit is used to connect the positive pole of the energy storage unit, and the second end of the switch unit is respectively connected to the first end of the first protection unit, the first end of the pre-charging unit, and the first end of the secondary power supply unit. The second end of the first protection unit is respectively connected to the second end of the pre-charging unit and the first end of the external device, and the third end of the first protection unit is connected to the first end of the control module. The third end of the pre-charging unit is connected to the second end of the control module. The second end of the secondary power supply unit is connected to the third end of the control module, and the third end of the secondary power supply unit is used to connect the negative pole of the energy storage unit and the external device.

[0044] Among them, when the energy storage system and / or circuit performs a black start, the switch unit is specifically used as a common switch for the primary system and the secondary system. When the switch unit is turned on, the secondary power supply unit is used to power the control module and other secondary systems, and after the pre-charging is completed, the first protection unit is turned on to power the primary system. In this process, the control circuit does not need to additionally set up a low-voltage power supply (such as a UPS module, etc.) that is specifically used to continuously power the control module and other secondary systems. That is, the circuit provided in the embodiment of the present application can achieve a black start with a relatively simple circuit design with low operation and maintenance costs.

[0045] In addition, when the over-discharge protection is triggered, although the circuit provided in the embodiment of the present application disconnects the first protection unit so that the energy storage unit cannot output electric energy to the external device, the energy storage unit still remains online with the DC bus and / or the external power supply through the pre-charging unit during the over-discharge protection, that is, the energy storage system is not completely decoupled from the bus. In this way, the energy storage system can immediately absorb the power generation of new energy, improve the response speed of the energy storage system, and reduce the amount of abandoned solar and / or wind power.

[0046] In this way, the energy storage unit can achieve the effect of seamlessly absorbing the excess power generated by the external power source, and can also achieve black start with a relatively simple circuit design with low operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 A schematic diagram of the structure of a control circuit of a first energy storage system provided in an embodiment of the present application;

[0049] Figure 2 A schematic diagram of the structure of a control circuit of a second energy storage system provided in an embodiment of the present application;

[0050] Figure 3 A schematic diagram of the structure of a control circuit of a third energy storage system provided in an embodiment of the present application;

[0051] Figure 4 A schematic diagram of the structure of a control circuit of a fourth energy storage system provided in an embodiment of the present application;

[0052] Figure 5 A schematic diagram of the structure of a control circuit of a fifth energy storage system provided in an embodiment of the present application;

[0053] Figure 6 A schematic diagram of the structure of a control circuit of a sixth energy storage system provided in an embodiment of the present application;

[0054] Figure 7 A flow chart of a control method for an energy storage system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0056] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0057] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0058] In the description of the present application, it should be noted that the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0059] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0060] The energy storage system is generally equipped with secondary devices such as batteries, over-discharge protection units, over-charge protection units, uninterruptible power supply (UPS) modules, and controllers. The batteries in the energy storage system are directly coupled to the DC bus through the contactors of the protection units. In addition, when the over-discharge protection or over-charge protection is triggered, the over-discharge protection unit or over-charge protection unit will trip the contactor to protect the battery. In addition, the controller can also be powered by the UPS module to enable the energy storage system to perform a black start.

[0061] However, when the over-discharge protection is triggered, the solution of the related art will directly control the decoupling of the over-discharge protection battery and the DC bus, making the system unavailable, which in turn makes it impossible to achieve the purpose of seamless absorption when the energy storage unit is required to absorb the excess power generation. In addition, since this solution also requires black start through the UPS module, there are also problems such as complex system design and high operation and maintenance costs.

[0062] To this end, an embodiment of the present application provides a control circuit for an energy storage system, by setting a switch unit, a first protection unit, a pre-charging unit, a secondary power supply unit and a control module in the control circuit. The first end of the switch unit is connected to the positive electrode of the energy storage unit, and the second end of the switch unit is respectively connected to the first end of the first protection unit, the first end of the pre-charging unit, and the first end of the secondary power supply unit; the second end of the first protection unit is respectively connected to the second end of the pre-charging unit and the first end of the external device, and the third end of the first protection unit is connected to the first end of the control module; the third end of the pre-charging unit is connected to the second end of the control module, the second end of the secondary power supply unit is connected to the third end of the control module, and the third end of the secondary power supply unit is used to connect the negative electrode of the energy storage unit and the external device. In this way, the energy storage unit can achieve the effect of seamlessly absorbing the excess power generation of the external power supply, and can also achieve black start with a relatively simple circuit design with low operation and maintenance costs.

[0063] The embodiments of the present application are described by taking the control circuit applied in the energy storage system as an example, but it does not mean that the embodiments of the present application can only be applied to the energy storage system for black start and / or over-discharge protection.

[0064] The control circuit of the energy storage system provided in the embodiment of the present application is explained in detail below.

[0065] Figure 1 This is a schematic diagram of the structure of a control circuit of an energy storage system provided in this application. Figure 1 An embodiment of the present application provides a control circuit of an energy storage system, and the control circuit 100 includes: a switch unit 101, a first protection unit 102, a pre-charging unit 103, a secondary power supply unit 104 and a control module 105.

[0066] The first end of the switch unit 101 is used to connect the positive electrode of the energy storage unit, and the second end of the switch unit 101 is respectively connected to the first end of the first protection unit 102, the first end of the pre-charging unit 103, and the first end of the secondary power supply unit 104.

[0067] The second end of the first protection unit 102 is connected to the second end of the pre-charging unit 103 and the first end of the external device respectively, and the third end of the first protection unit 102 is connected to the first end of the control module 105 .

[0068] The third end of the pre-charging unit 103 is connected to the second end of the control module 105 .

[0069] The second end of the secondary power supply unit 104 is connected to the third end of the control module 105 , and the third end of the secondary power supply unit 104 is used to connect the negative electrode of the energy storage unit and the external device.

[0070] The switch unit 101 is used to switch on or off the transmission path of the energy storage unit.

[0071] The first protection unit 102 is used to be turned on or off under the control of the control module 105 to turn on or off the first transmission path of the energy storage unit.

[0072] The pre-charging unit 103 is used to output the electric energy output by the energy storage unit to the external device through the second transmission path when it is turned on, and to transmit the electric energy input by the external power supply to the energy storage unit through the second transmission path when it is turned off.

[0073] The secondary power supply unit 104 is used to supply power to the control module 105 when the switch unit 101 is turned on.

[0074] The control module 105 is used to control the pre-charging unit 103 to be turned on after power-on, and to control the first protection unit 102 to be turned on after pre-charging is completed.

[0075] Optionally, the switch unit 101 may include at least one circuit breaker, and the positive electrode of the energy storage unit and the first end of the first protection unit 102 may be connected to the two ends of a normally open contact of the circuit breaker. The switch unit 101 may be manually controlled by relevant technicians or remotely controlled by any other possible device, which is not limited in the embodiments of the present application.

[0076] Specifically, when the switch unit 101 is disconnected, the transmission path of the energy storage unit can be cut off, and the transmission path of the energy storage unit can specifically refer to the line through which the energy storage unit outputs electrical energy to the circuit 100. That is, if the switch unit 101 is disconnected, the energy storage unit cannot supply power to the circuit 100 at all.

[0077] Optionally, the first protection unit 102 may include any controllable switching device, such as a relay, a contactor, etc., which is not limited in the embodiment of the present application.

[0078] Optionally, the control module 105 may also be configured to control the first protection unit 102 to be turned off when it is determined that the energy storage unit triggers over-discharge protection, so as to protect the energy storage unit.

[0079] Specifically, when the first protection unit 102 is disconnected, the first transmission path of the energy storage unit can be cut off, and the first transmission path of the energy storage unit can specifically refer to the line through which the energy storage unit supplies power to the external device through the switch unit 101 and the first protection unit 102. That is, if the first protection unit 102 is disconnected, the energy storage unit cannot supply power to the external device through the first protection unit 102, but can supply power to the external device through the pre-charging unit 102.

[0080] Optionally, the pre-charging unit 103 may be specifically controlled by the control module 105 .

[0081] Generally, when the first protection unit 102 is turned on, it is equivalent to that the pre-charging unit 103 is short-circuited. At this time, the control module 105 may not output a signal to the pre-charging unit 103 .

[0082] When the first protection unit 102 is disconnected, if the external device needs to be powered on for pre-charging, the pre-charging unit 103 can be controlled to be turned on, so that the energy storage unit pre-charges the external device through the pre-charging unit 103. If the external power source needs to charge the energy storage unit, even if the pre-charging unit 103 is turned off, the energy storage unit can be transmitted to the energy storage unit through the power source input from the pre-charging unit 103.

[0083] In this embodiment, the second transmission path refers to the line through which the energy storage unit transmits electric energy to the external device through the switch unit 101 and the pre-charging unit 103. Specifically, the energy storage unit can output electric energy to the external device through the switch unit 101 and the pre-charging unit 103, and the external device can also output electric energy to the energy storage unit through the pre-charging unit 103 and the switch unit 101.

[0084] Generally, because the pre-charging unit 103 is used to pre-charge the external device to prevent excessive surge current from being generated at the moment the power is turned on, the pre-charging unit 103 can use a current with a smaller current value to pre-charge the external device. The first transmission path is a line that enables the energy storage unit to provide working power to the external device after the pre-charging is completed. Therefore, the energy storage unit needs to output a larger current to ensure that the external device can be powered on and work normally.

[0085] It can be seen from the above that the current flowing through the first transmission path can be greater than the current flowing through the second transmission path.

[0086] In addition, when the pre-charging unit 103 is turned on, the second transmission path can be regarded as being fully turned on. If the pre-charging unit 103 is turned off, the energy storage unit cannot supply power to the external device through the pre-charging unit 103, but the external device can supply power to the energy storage unit through the pre-charging unit 102. In this case, the second transmission path can be regarded as being in a unidirectional conduction state in which the external device transmits power to the energy storage unit.

[0087] Optionally, the secondary power supply unit 104 may include a direct current-to-direct current (DC-DC) converter, and the secondary power supply unit 104 may be specifically used to convert the electric energy output by the energy storage unit into an operating voltage required by the control module 105 and other secondary loads in the circuit 100 .

[0088] Optionally, the control module 105 can be any device with processing, calculation, detection, control and other functions. For example, the control module 105 can be a battery management system (Battery Management System, referred to as BMS), or other microcontroller units (MCU) that can implement corresponding functions, etc., and the embodiments of the present application are not limited to this.

[0089] In this embodiment, continue to see Figure 1 The external device may be a power conversion system (PCS) or any other possible device. Generally, if the external device is a PCS, the energy storage unit may pre-charge the capacitor C0 in the PCS through the pre-charging unit 103 .

[0090] In this embodiment, the external power source may refer to a generator set, such as a wind power generator set, a photovoltaic power generation device, or any other possible new energy generator set, or may refer to any other possible power source. This embodiment of the application does not limit this.

[0091] It is worth noting that in order to better introduce the control circuit 100 provided in the embodiment of the present application, the working principle of the control circuit 100 is explained below by taking the external device as a PCS and the external power source as a new energy generator set as an example:

[0092] In the initial state or in sleep mode, the energy storage unit does not need to be discharged or charged, the switch unit 101 can be turned off, and the external power supply does not output power to the circuit 100. Therefore, in this case, the secondary power supply unit 104 will not be powered on to provide the control module 105 with a working voltage, and the first protection unit 102 and the pre-charging unit 103 can also be in a closed state.

[0093] When the external device needs to be powered on and the energy storage unit needs to output electric energy through the circuit 100, the switch unit 101 can be turned on first, and at this time, the energy storage unit can supply power to the secondary power supply unit 104, so that the secondary power supply unit 104 provides the working voltage to the control module 105. Further, the control module 105 can control the pre-charging unit 103 to be turned on, so that the energy storage unit pre-charges the capacitor C0 in the PCS through the pre-charging unit 103.

[0094] After the pre-charging is completed, the control module 105 can control the first protection unit 102 to be turned on, so that the energy storage unit can provide a large current to the PCS through the first protection unit 102, so that the PCS can work normally. At the same time, the control module 105 can further control the pre-charging unit 103 to be turned off. In this way, the black start of the energy storage system and / or circuit 100 can be completed.

[0095] When the external device needs to be powered off and hibernate, or the energy storage unit triggers the over-discharge protection, the control module 105 can control the first protection unit 102 to be turned off, and control the pre-charging unit 103 to be turned on. In this way, the energy storage unit can be kept online with the DC bus and / or the external device and / or the external power supply through the pre-charging unit 103. In addition, if the external power supply needs to charge the energy storage unit at this time, the external power supply can output electrical energy to the energy storage unit through the pre-charging unit 103, and then when the control module 105 detects that the energy storage unit has entered the charging state, it can control the first protection unit 102 to be turned on, and the over-discharge protection can be released, so that the energy storage system is adjusted to the state of charging the energy storage unit.

[0096] It is understandable that if the external power source is a new energy power generation set such as a wind power generator set, a photovoltaic power generation device, etc., a sudden increase in power generation often occurs. Therefore, the energy storage unit is still kept online with the DC bus and / or the external power source through the pre-charging unit 103 during over-discharge protection, so that the energy storage system can immediately absorb the power generation of the new energy, improve the response speed of the energy storage system, and reduce the amount of abandoned light and / or wind power.

[0097] It is worth noting that, from the working principle of the circuit 100 introduced above, it can be seen that when the energy storage system and / or the circuit 100 performs a black start, the switch unit 101 is specifically used as a common switch for the primary system and the secondary system. When the switch unit 101 is turned on, the secondary power supply unit 104 supplies power to the control module 105 and other secondary systems, and after the pre-charging is completed, the first protection unit 102 is turned on to supply power to the primary system. In this process, the control circuit 100 does not need to additionally set up a low-voltage power supply (such as a UPS module, etc.) that is specifically used to continuously supply power to the control module 105 and other secondary systems. That is, the circuit 100 provided in the embodiment of the present application can achieve a black start with a relatively simple circuit design with low operation and maintenance costs.

[0098] In addition, when the circuit 100 provided in the embodiment of the present application triggers the over-discharge protection, although the first protection unit 102 is disconnected so that the energy storage unit cannot output electric energy to the external device, the energy storage unit still remains online with the DC bus and / or the external power supply through the pre-charging unit 103 during the over-discharge protection, that is, the energy storage system is not completely decoupled from the bus, and therefore, the energy storage unit can achieve the effect of seamlessly absorbing the excess power generation of the external power supply.

[0099] In the embodiment of the present application, a switch unit 101, a first protection unit 102, a pre-charging unit 103, a secondary power supply unit 104 and a control module 105 are provided in the control circuit 100. The first end of the switch unit 101 is used to connect the positive electrode of the energy storage unit, and the second end of the switch unit 101 is respectively connected to the first end of the first protection unit 102, the first end of the pre-charging unit 103, and the first end of the secondary power supply unit 104. The second end of the first protection unit 102 is respectively connected to the second end of the pre-charging unit 103 and the first end of the external device, and the third end of the first protection unit 102 is connected to the first end of the control module 105. The third end of the pre-charging unit 103 is connected to the second end of the control module 105. The second end of the secondary power supply unit 104 is connected to the third end of the control module 105, and the third end of the secondary power supply unit 104 is used to connect the negative electrode of the energy storage unit and the external device.

[0100] Among them, when the energy storage system and / or circuit 100 performs a black start, the switch unit 101 is specifically used as a common switch for the primary system and the secondary system. When the switch unit 101 is turned on, the secondary power supply unit 104 supplies power to the control module 105 and other secondary systems, and after the pre-charging is completed, the first protection unit 102 is turned on to supply power to the primary system. In this process, the control circuit 100 does not need to additionally set up a low-voltage power supply (such as a UPS module, etc.) that is specifically used to continuously supply power to the control module 105 and other secondary systems. That is, the circuit 100 provided in the embodiment of the present application can achieve a black start with a relatively simple circuit design with low operation and maintenance costs.

[0101] In addition, when the circuit 100 provided in the embodiment of the present application triggers the over-discharge protection, although the first protection unit 102 is disconnected, so that the energy storage unit cannot output electric energy to the external device, the energy storage unit still remains online with the DC bus and / or the external power supply through the pre-charging unit 103 during the over-discharge protection, that is, the energy storage system is not completely decoupled from the bus, so that the energy storage system can immediately absorb the power generation of new energy, improve the response speed of the energy storage system, and reduce the amount of abandoned solar and / or wind power.

[0102] In this way, the energy storage unit can achieve the effect of seamlessly absorbing the excess power generated by the external power source, and can also achieve black start with a relatively simple circuit design with low operation and maintenance costs. In addition, since the energy storage unit does not disconnect from the busbar when the over-discharge protection is triggered, it can seamlessly absorb the power generation, so the energy storage unit can operate at 100% discharge depth (DOD).

[0103] For a possible implementation, see Figure 2 The pre-charge unit 103 includes a resistor R and a switch tube Q.

[0104] The first end of the resistor R is connected to the second end of the switch unit 101, the second end of the resistor R is connected to the first pole of the switch tube Q, the second pole of the switch tube Q is connected to the second end of the first protection unit 102, and the third pole of the switch tube Q is connected to the second end of the control module 105.

[0105] Optionally, the switch tube Q is used to be turned on or off under the control of the control switch, and is used to output the electric energy output by the energy storage unit to the external device when turned on, and to transmit the electric energy input by the external power supply to the energy storage unit when turned off.

[0106] Optionally, the switch tube Q can be any other possible type of switch tube such as a MOS tube or an IGBT tube. Specifically, an N-channel switch tube or a P-channel switch tube can be selected according to actual needs, and the embodiment of the present application does not limit this.

[0107] Optionally, the resistor R may be used as a current limiting resistor, and specific parameters of the resistor R may be selected according to the circuit structure and actual parameters of other components.

[0108] In addition, the control module 105 can detect that the energy storage unit has entered the charging state by setting a corresponding current direction detection element at the positive or negative electrode of the energy storage unit, and the control module 105 obtains the output value of the current direction detection element to determine whether the current is flowing to the energy storage unit or flowing out of the energy storage unit. If the current is flowing to the energy storage unit, it can be determined that the current is in the charging state, and if the current is flowing out of the energy storage unit, it can be determined that the current is in the discharging state.

[0109] It is understandable that when the switch tube Q is turned off, if the external power source needs to charge the energy storage unit, even if the switch tube Q is in the off state, the switch tube Q will generate a certain leakage current under the action of the external power source and transmit it to the energy storage unit. In this way, the energy storage unit and the external power source (and / or DC bus) can be kept online.

[0110] Moreover, the pre-charging circuit 103 composed of the resistor R and the switch tube Q also has the advantages of quick response, no arc, and low heat generation.

[0111] For a possible implementation, see Figure 2 , the control circuit 100 also includes: a second protection unit 106.

[0112] A first end of the second protection unit 106 is connected to a second end of the switch unit 101 , a second end of the second protection unit 106 is connected to a first end of the first protection unit 102 , and a third end of the second protection unit 106 is connected to a fourth end of the control module 105 .

[0113] Optionally, the second protection unit 106 is used to be turned on or off under the control of the control module 105 to turn on or off the first transmission path of the energy storage unit.

[0114] Optionally, the second protection unit 106 may include any controllable switching device, such as a relay, a contactor, etc., which is not limited in the embodiment of the present application.

[0115] In this embodiment, when the second protection unit 106 is disconnected, the first transmission path of the energy storage unit can be cut off, and the first transmission path of the energy storage unit can specifically refer to the line through which the energy storage unit supplies power to the external device through the switch unit 101, the second protection unit 106, and the first protection unit 102. That is, if the second protection unit 106 is disconnected, the energy storage unit cannot supply power to the external device through the second protection unit 106.

[0116] In addition, the control module 105 can also be used to control the second protection unit 106 to be turned off when it is determined that the energy storage unit triggers the overcharge protection, so as to achieve the purpose of protecting the energy storage unit.

[0117] Optionally, the circuit breaker in the switch unit 101 may include one or more normally open switches and a control coil. The first protection unit 102 includes a first relay, and the second protection unit 106 includes a second relay.

[0118] For example, see Figure 3 The circuit breaker in the switch unit 101 may include two normally open switches and two control coils X1. One normally open switch of the circuit breaker is arranged between the positive electrode of the energy storage unit and the first end of the second protection unit 106, and the other normally open switch is arranged between the negative electrode of the energy storage unit and the third end of the secondary power supply unit 104.

[0119] The two control coils X1 can be connected to the third end of the control module 105 respectively, and then the control module 105 can output electric energy to the control coils X1 to realize the function of automatically controlling the switch unit 101 to be turned on or off.

[0120] The normally open switch of the first relay is connected between the second end of the second protection unit 106 and the second end of the pre-charging unit 103 , and the control coil X2 of the first relay is connected to the first end of the control module 105 .

[0121] When the first relay needs to be controlled to be closed, the control module 105 can supply power to the control coil X2 so that the control coil X2 controls the normally open switch of the first relay to be closed. When the first relay needs to be controlled to be opened, the control module 105 can stop supplying power to the control coil X2 so that the control coil X2 releases the normally open switch of the first relay.

[0122] The normally open switch of the second relay is connected between the second end of the switch unit 101 and the first end of the first protection unit 102 , and the control coil X3 of the second relay is connected to the fourth end of the control module 105 .

[0123] When the second relay needs to be controlled to be closed, the control module 105 can supply power to the control coil X3 so that the control coil X3 controls the normally open switch of the second relay to be closed. When the second relay needs to be controlled to be disconnected, the control module 105 can stop supplying power to the control coil X3 so that the control coil X3 releases the normally open switch of the second relay.

[0124] In this embodiment, since the second protection unit 106 is provided, when controlling the energy storage system and / or the circuit 100 to perform a black start, it is necessary to control the second protection unit 106 to be turned on.

[0125] In this way, the first protection unit 102 can be turned off when the energy storage unit triggers the over-discharge protection, and the second protection unit 106 can be turned off when the over-charge protection is triggered. This can avoid the problem that when the over-charge protection is triggered, even if the first protection unit 102 is turned off, the external power source may still charge the energy storage unit through the pre-charge unit 103, so that the safety and reliability of the circuit 100 can be improved.

[0126] For a possible implementation, see Figure 4 , the control circuit 100 also includes: a backup power holding unit 107.

[0127] A first end of the backup power holding unit 107 is connected to a second end of the switch unit 101 , a second end of the backup power holding unit 107 is connected to a first end of the first protection unit 102 , and a third end of the backup power holding unit 107 is connected to a collection end of the control module 105 .

[0128] The backup power holding unit 107 is used to output the electric energy output by the energy storage unit to the first protection unit 102 , and to prevent the electric energy input by the external power supply from being transmitted to the energy storage unit through the backup power holding unit 107 .

[0129] The control module 105 is further used to collect the voltage of the backup power holding unit 107 and control the second protection unit 106 to be turned on or off based on the voltage.

[0130] Optionally, the backup power holding unit 107 may have a unidirectional conduction characteristic, that is, the current can only flow to the second end of the backup power holding unit 107 through the first end of the backup power holding unit 107, and cannot flow from the second end of the backup power holding unit 107 to the first end of the backup power holding unit 107. In this way, it is possible to prevent the current from flowing back to the energy storage unit or causing other current interference problems.

[0131] Specifically, the control module 105 can be used to control the second protection unit 106 to turn on when the energy storage unit triggers overcharge protection and determines that the voltage meets the preset conditions. Otherwise, the control module 105 needs to keep the second protection unit 106 turned off.

[0132] Optionally, the preset condition may refer to the voltage being greater than a voltage threshold set in advance. Generally, after the energy storage unit triggers the overcharge protection, the second protection unit 106 is turned off, and due to the unidirectional conduction of the backup power holding unit 107, the external power supply cannot charge the energy storage unit at this time, so the voltage of the backup power holding unit 107 should be 0.

[0133] If the voltage is greater than a voltage threshold set in advance, it can be indicated that the circuit 100 is currently connected to a load and the energy storage unit supplies power to the outside through the backup power holding unit 107 .

[0134] In this embodiment, although a backup power holding unit 107 is provided, when controlling the black start of the energy storage system and / or circuit 100, it is necessary to first control the second protection unit 106 to be turned on, and then control the conduction, and then control the first protection unit 102 to be turned on after the pre-charging is completed, so as to ensure that the energy storage unit can output a large current to the external device and prevent the circuit 100 from oscillating.

[0135] It is worth noting that in the case of overcharge protection of the energy storage unit, the second protection unit 106 is disconnected, and the energy storage unit can be kept online with the DC bus and / or the external device through the backup power holding unit 107, that is, the circuit 100 is in power supply standby mode. If an external device or other load is connected to the energy storage unit through the circuit 100, the energy storage unit can first output electric energy to the external device or other load through the backup power holding unit 107, and when the control module 105 detects that the voltage of the backup power holding unit 107 meets the preset conditions, the second protection unit 106 can be controlled to be turned on, so that the energy storage unit releases the overcharge protection and enters the discharge mode, and can output a large current to the external device or other load through the second protection unit 106 and the first protection unit 102.

[0136] In this way, the energy storage unit can realize the function of providing seamless backup power for the load, so as to improve the reliability and practicality of the circuit 100.

[0137] In addition, since the energy storage unit does not disconnect from the bus when the overcharge protection is triggered and can seamlessly supply power to the load, the energy storage unit can operate at 100% depth of discharge (DOD).

[0138] For a possible implementation, see Figure 5 The backup power holding unit 107 includes: a diode D and a reactor L.

[0139] The anode of the diode D is connected to the second end of the switch unit 101 , the cathode of the diode D is connected to the first end of the reactor L, and the second end of the reactor L is connected to the first end of the first protection unit 102 .

[0140] The first end and the second end of the reactor L are connected to the collection end of the control module 105 respectively.

[0141] Optionally, the diode D has a unidirectional conduction characteristic.

[0142] In addition, the voltage of the backup power holding unit 107 may specifically refer to the voltage (induced electromotive force) across the reactor L, which is not limited in the embodiment of the present application.

[0143] It is worth noting that the reactor L can act as a damper to prevent the circuit 100 and / or the energy storage system from short-circuiting due to excessive surge current when an external device or other load is connected to the energy storage unit through the circuit 100 .

[0144] In this way, the stability of the circuit 100 and the backup power holding unit 107 can be improved.

[0145] It is worth noting that the discharge current of the reactor L lags behind the voltage change of the reactor L. Therefore, by detecting the voltage of the reactor L, it is helpful for the control module 105 to determine in advance whether the energy storage unit has entered a state of load discharge. The control module 105 can close and turn on the second protection unit 106 more quickly, thereby preventing the diode D from being subjected to overload current for a long time.

[0146] For a possible implementation, see Figure 6 The control module 105 includes a voltage sampling unit 1051 and an execution unit 1052 .

[0147] A first end and a second end of the voltage sampling unit 1051 are connected to a first end and a second end of the reactor L, respectively.

[0148] Optionally, the voltage sampling unit 1051 may be any component that can be used to detect voltage, for example, an analog front end (Analog Front-end, AFE for short).

[0149] Optionally, the voltage sampling unit 1051 is used to collect the voltage of the reactor L, and send the voltage of the reactor L to the execution unit 1052 .

[0150] Optionally, the execution unit 1052 may be any possible element with processing, control and other functions, such as MCU, DSP, etc. In addition, the voltage sampling unit 1051 and the execution unit 1052 may be integrated in the same module or the same device, for example, in a BMS.

[0151] Optionally, the execution unit 1052 is used to control the second protection unit 106 to be turned on or off based on the voltage of the reactor L, and to control the first protection unit 102, the pre-charging unit 103, and the switch unit 101 to be turned on or off.

[0152] Specifically, the execution unit 1052 can control the second protection unit 106 to be disconnected when the energy storage unit triggers the overcharge protection; when the energy storage unit triggers the overcharge protection and it is determined that the voltage of the reactor L meets the above preset conditions, the second protection unit 106 is controlled to be turned on.

[0153] In addition, the execution unit 1052 is also used to turn on the second protection unit 106 and the pre-charging unit 103 in sequence when power is first supplied, and control the first protection unit 102 to turn on and the pre-charging unit 103 to turn off after the pre-charging is completed.

[0154] The execution unit 1052 is further configured to shut down the first protection unit 102 when it is detected that the energy storage unit triggers over-discharge protection, and shut down the second protection unit 106 when it is detected that the energy storage unit triggers over-charge protection.

[0155] In a possible implementation, see Figure 6 The sixth end of the control module 105 is also connected to the third end of the switch unit 101, the seventh end of the control module 105 is also connected to the communication end of the external device, and the eighth end of the control module 105 is also connected to the power supply end of the external device.

[0156] Optionally, the external device may be the PCS mentioned above. The external device is used to power the control module 105. Specifically, when the energy storage system and / or the circuit 100 is completely powered off and the switch unit 101 is not turned on, the external device can power the control module 105 and other secondary systems.

[0157] It is understandable that, since the external device can supply power to the control module 105 , the purpose of remotely waking up the control module 105 and / or the circuit 100 can be achieved by controlling the external device.

[0158] Optionally, the control module 105 is further configured to control the switch unit 101 to disconnect when the energy storage unit triggers undervoltage protection, thereby preventing the energy storage unit from being continuously discharged and causing irreversible damage.

[0159] The control module 105 may also be used to receive and respond to a control instruction sent by the external device to control the switch unit 101 to be turned on or off.

[0160] Optionally, the control instruction may be used to instruct the control module 105 to control the circuit 100 and / or the energy storage system to perform a black start, or to instruct the control module 105 to control the circuit 100 and / or the energy storage system to shut down or sleep.

[0161] It is understandable that when the control instruction indicates a black start, the switch unit 101 is controlled to be turned on. When the control instruction indicates shutdown or sleep, the switch unit 101 is controlled to be turned off. In this way, the function of turning on and off the remote control circuit 100 can be realized.

[0162] The following describes the control method of the energy storage system, the computer-readable storage medium, etc. applied to the control circuit of the energy storage system provided in the present application. The specific implementation process and technical effects are as mentioned above and will not be repeated below.

[0163] Figure 7 is a flow chart of a control method of an energy storage system provided in an embodiment of the present application. The method can apply the control circuit 100 of the energy storage system provided in any of the above embodiments, and can be specifically executed by the control module 105 in the control circuit 100. Figure 7 , the method comprising:

[0164] Step 2001: In response to the switch unit being turned on, the pre-charging unit is controlled to be turned on, so that the energy storage unit pre-charges the external device.

[0165] Optionally, the switch unit may be the switch unit 101 mentioned above, the pre-charging unit may be the pre-charging unit 103 mentioned above, and the external device may be the PCS mentioned above.

[0166] Optionally, if the circuit 100 further includes a second protection unit 106, the second protection unit 106 may be controlled to be turned on before the pre-charging unit is controlled to be turned on.

[0167] Step 2002: When it is confirmed that the pre-charging is completed, the first protection unit is controlled to be turned on and the pre-charging unit is controlled to be turned off, so that the energy storage system is black-started.

[0168] For example, if the capacitor C0 in the PCS is pre-charged, then whether the pre-charging is completed can be determined by detecting the voltage, charge amount or capacitance value of the capacitor C0.

[0169] Optionally, the first protection unit may be the first protection unit 102 mentioned above.

[0170] In this way, the pre-charging unit is turned on first and then the first protection unit is turned on, so as to prevent the circuit 100 from oscillating.

[0171] Step 2003: In response to the energy storage unit triggering the over-discharge protection state, controlling the first protection unit to shut down.

[0172] Optionally, when the first protection unit is controlled to be turned off, the pre-charging unit can also be controlled to be turned off. In this way, the problem of the energy storage unit continuously discharging to the outside and causing damage to the energy storage unit can be avoided.

[0173] Step 2004: When it is determined that the energy storage unit is in a charging state, the first protection unit is controlled to be turned on to release the over-discharge protection state.

[0174] Optionally, whether the energy storage unit is in a charging state or a discharging state may be determined by the current direction on the busbar and / or the positive electrode of the energy storage unit.

[0175] It is worth noting that the method provided in the embodiment of the present application can achieve black start in a relatively simple manner with low operation and maintenance costs, and can enable the energy storage system to immediately absorb the power generation of new energy, improve the response speed of the energy storage system, and reduce the amount of abandoned solar and / or wind power.

[0176] In a possible implementation, when the control circuit further includes a second protection unit and a backup power holding unit, the method further includes:

[0177] In response to the energy storage unit triggering the overcharge protection state, the second protection unit is controlled to be turned off, so that the control circuit is in a standby state.

[0178] Optionally, the standby state refers to a state in which the energy storage unit cannot be charged through the first protection unit, the second protection unit and the switch unit.

[0179] The voltage of the backup power holding unit is detected in real time.

[0180] Optionally, the voltage across the reactor in the backup power holding unit may be detected.

[0181] When the voltage of the backup power holding unit meets a preset condition, the second protection unit is controlled to be turned on to release the overcharge protection state.

[0182] The voltage of the backup power holding unit is used to indicate whether the energy storage unit is discharging to an external device.

[0183] Optionally, the preset condition may mean that the voltage is greater than a voltage threshold set in advance.

[0184] It can be understood that in the standby state, the energy storage unit is also kept online with the bus and / or external equipment through the backup power holding unit. Therefore, when the external equipment is connected to the energy storage unit through the control circuit, the energy storage unit discharges to the outside through the backup power holding unit, so that after the voltage of the backup power holding unit meets the preset conditions, the control module can control the second protection unit to be turned on, so that the energy storage unit can realize the function of providing seamless backup power for the load.

[0185] In addition, the method provided in the embodiment of the present application and the above-mentioned control circuit 100 belong to the same inventive concept, so the method may also include any other possible steps to achieve any technical effect and function that the control circuit 100 can achieve. The embodiment of the present application is not described in detail here.

[0186] An embodiment of the present application further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented.

[0187] Optionally, the present application also provides a program product, such as a computer-readable storage medium, including a program, which, when executed by a processor, is used to execute an embodiment of any of the above-mentioned energy storage system control methods.

[0188] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only 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 devices or units, which can be electrical, mechanical or other forms.

[0189] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0190] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0191] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (English: processor) to perform some steps of the methods of various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (English: Read-Only Memory, abbreviated: ROM), random access memory (English: Random Access Memory, abbreviated: RAM), disk or optical disk and other media that can store program codes.

[0192] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0193] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A control circuit of an energy storage system, characterized in that: The control circuit includes: a switch unit, a first protection unit, a pre-charging unit, a secondary power supply unit and a control module; The first end of the switch unit is used to connect the positive electrode of the energy storage unit, and the second end of the switch unit is respectively connected to the first end of the first protection unit, the first end of the pre-charging unit, and the first end of the secondary power supply unit; the switch unit is used to turn on or off the transmission path of the energy storage unit; The second end of the first protection unit is connected to the second end of the pre-charging unit and the first end of the external device respectively, and the third end of the first protection unit is connected to the first end of the control module; the first protection unit is used to turn on or off under the control of the control module to turn on or off the first transmission path of the energy storage unit; The third end of the pre-charging unit is connected to the second end of the control module; the pre-charging unit is used to output the electric energy output by the energy storage unit to the external device through the second transmission path when turned on, and to transmit the electric energy input by the external power supply to the energy storage unit through the second transmission path when turned off, and the pre-charging unit is controlled by the control module; the current flowing through the first transmission path is greater than the current flowing through the second transmission path; The second end of the secondary power supply unit is connected to the third end of the control module, and the third end of the secondary power supply unit is used to connect the negative electrode of the energy storage unit and the external device; the secondary power supply unit is used to supply power to the control module when the switch unit is turned on; The control module is used to control the pre-charging unit to be turned on after power-on, and to control the first protection unit to be turned on after pre-charging is completed.

2. The control circuit of the energy storage system according to claim 1, characterized in that: The pre-charging unit includes a resistor and a switch tube; The first end of the resistor is connected to the second end of the switch unit, the second end of the resistor is connected to the first pole of the switch tube, the second pole of the switch tube is connected to the second end of the first protection unit, and the third pole of the switch tube is connected to the second end of the control module; The switch tube is used to be turned on or off under the control of the control switch, and is used to output the electric energy output by the energy storage unit to the external device when turned on, and to transmit the electric energy input by the external power supply to the energy storage unit when turned off.

3. The control circuit of the energy storage system according to claim 1, characterized in that: The control circuit further includes: a second protection unit; The first end of the second protection unit is connected to the second end of the switch unit, the second end of the second protection unit is connected to the first end of the first protection unit, and the third end of the second protection unit is connected to the fourth end of the control module; The second protection unit is used to be turned on or off under the control of the control module to turn on or off the first transmission path of the energy storage unit.

4. The control circuit of the energy storage system according to claim 3, characterized in that: The control circuit further includes: a backup power holding unit; The first end of the backup power holding unit is connected to the second end of the switch unit, the second end of the backup power holding unit is connected to the first end of the first protection unit, and the third end of the backup power holding unit is connected to the collection end of the control module; The backup power holding unit is used to output the electric energy output by the energy storage unit to the first protection unit, and to prevent the electric energy input by the external power supply from being transmitted to the energy storage unit through the backup power holding unit; The control module is further used to collect the voltage of the backup power holding unit, and control the second protection unit to be turned on or off based on the voltage.

5. The control circuit of the energy storage system according to claim 4, characterized in that: The backup power holding unit comprises: a diode and a reactor; The anode of the diode is connected to the second end of the switch unit, the cathode of the diode is connected to the first end of the reactor, and the second end of the reactor is connected to the first end of the first protection unit; The first end and the second end of the reactor are respectively connected to the collection end of the control module.

6. The control circuit of the energy storage system according to claim 5, characterized in that: The control module includes a voltage sampling unit and an execution unit; The first end and the second end of the voltage sampling unit are connected to the first end and the second end of the reactor respectively; the voltage sampling unit is used to collect the voltage of the reactor and send the voltage of the reactor to the execution unit; The execution unit is used to control the second protection unit to be turned on or off based on the voltage of the reactor, and to control the first protection unit, the pre-charging unit, and the switching unit to be turned on or off.

7. The control circuit of the energy storage system according to claim 1, characterized in that: The sixth end of the control module is also connected to the third end of the switch unit, the seventh end of the control module is also connected to the communication end of the external device, and the eighth end of the control module is also connected to the power supply end of the external device; The external device is used to supply power to the control module; The control module is also specifically used to control the switch unit to be disconnected when the energy storage unit triggers undervoltage protection, and to receive and respond to the control instruction sent by the external device to control the switch unit to be turned on or off.

8. The control circuit of the energy storage system according to claim 1, characterized in that: The first protection unit includes a first relay; the switch unit includes at least one circuit breaker; and the secondary power supply unit includes a DC-DC converter.

9. A control method for an energy storage system, characterized in that: A control circuit for an energy storage system provided in any one of claims 1 to 8, the control circuit comprising: a switch unit, a first protection unit, a pre-charging unit, a secondary power supply unit and a control module; the method comprising: In response to the switch unit being turned on, controlling the pre-charging unit to be turned on, so that the energy storage unit pre-charges the external device; When confirming that the pre-charging is completed, controlling the first protection unit to be turned on and the pre-charging unit to be turned off, so that the energy storage system is black-started; In response to the energy storage unit triggering an over-discharge protection state, controlling the first protection unit to shut down; When it is determined that the energy storage unit is in a charging state, the first protection unit is controlled to be turned on to release the over-discharge protection state.

10. The control method of the energy storage system according to claim 9, characterized in that: In the case where the control circuit further includes a second protection unit and a backup power holding unit, the method further includes: In response to the energy storage unit triggering an overcharge protection state, controlling the second protection unit to be turned off so that the control circuit is in a standby state; Detecting the voltage of the backup power holding unit in real time; When the voltage of the backup power holding unit meets a preset condition, the second protection unit is controlled to be turned on to release the overcharge protection state; wherein the voltage of the backup power holding unit is used to indicate whether the energy storage unit discharges to an external device.

Images