Direct-current direct-hanging type energy storage system, control method, device and equipment and storage medium

Abstract

The invention provides a direct current direct hanging type energy storage system, a control method, a control device, equipment and a storage medium, the method comprises the direct current direct hanging type energy storage system based on an energy storage battery, the energy storage system comprises N constant voltage modules and M voltage regulating modules, N is far greater than M, and N and M are natural numbers; the N constant voltage modules and the M voltage regulating modules are connected in series to a direct current power grid; the topological structure of the single constant voltage module is different from that of the single voltage regulating module; the single constant voltage module comprises a first battery cluster and a first half bridge; and the single voltage regulating module comprises a second battery cluster, a direct current pre-charging circuit, an LC filter circuit and a second half-bridge. According to the direct-current direct-hanging type energy storage system disclosed by the embodiment of the invention, the constant-voltage modules accounting for the majority do not need to be provided with LC filter circuits and direct-current pre-charging circuits, and only a small number of voltage regulating modules need to be subjected to PWM control, so that the switching loss is reduced, the switching efficiency is improved, the circuit cost is saved, and the control strategy is simplified.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current power transmission, and in particular to a direct current direct-mounted energy storage system and a control method, device, equipment and storage medium thereof. Background Art

[0002] As the installed capacity of new energy generators such as wind and solar energy gradually increases in my country's power system, DC transmission is becoming an important direction for future power grid development due to its advantages of low loss, no capacitance effect and long transmission distance. Large-scale new energy power plants are usually built in remote areas. Since the power grid structure is still weak, it is urgent to rely on energy storage technology to play a key role in power regulation and power grid support.

[0003] Configuring energy storage devices in the DC power grid can improve the system's regulation capabilities and support the efficient use of a high proportion of new energy.

[0004] Among them, the direct-mounted DC energy storage solution has become the preferred topology solution for energy storage applications in DC systems due to its modular design, battery remaining power (State Of Charge, SOC) segmentation management, fewer conversion links and high efficiency. Figure 1 The basic topology of a DC direct-mounted energy storage system based on a half-bridge submodule is shown, where one end connects the energy storage battery module to a discrete DC port (a, b) through an LC filter, and the other end connects to a medium- and high-voltage DC grid through an output port (A, B).

[0005] Figure 1 The topology shown adopts a carrier phase-shifted pulse width modulation strategy. In steady-state operation, each half-bridge submodule has two working states: the upper tube of the half-bridge is turned on and the lower tube is turned off, indicating that the module is put into operation; the upper tube of the half-bridge is turned off and the lower tube is turned on, indicating that the module is cut out. The control strategy of the half-bridge submodule is as follows: Figure 2 shown.

[0006] Figure 2 The control strategy shown in the figure has a large loss when the switching frequency of the half-bridge sub-module is high, and each half-bridge sub-module needs to be additionally configured with an LC filter circuit (such as Figure 1 As shown in Figure 1, the oscillating ripple current of the battery is eliminated, which increases the circuit complexity and hardware cost. Summary of the invention

[0007] To solve the above problems, the present disclosure provides a DC direct-mounted energy storage system and a control method thereof, which can significantly reduce the switching loss of the half-bridge power module, while reducing the LC filter circuit and DC pre-charging circuit required by most modules, thereby improving the conversion efficiency of the system and reducing the overall circuit cost.

[0008] The present disclosure is preferably implemented by the following scheme:

[0009] A DC direct-mounted energy storage system based on an energy storage battery, the energy storage system comprising N constant voltage modules and M voltage regulating modules, wherein N is greater than M, and N and M are natural numbers;

[0010] N constant voltage modules and M voltage regulating modules are connected in series to the DC grid;

[0011] The topology of a single constant voltage module is different from that of a single voltage regulating module:

[0012] The single constant voltage module includes a first battery cluster and a first half bridge;

[0013] A single voltage regulation module includes a second battery cluster, a DC pre-charging circuit, an LC filtering circuit, and a second half bridge.

[0014] Furthermore,

[0015] When the DC direct-mounted energy storage system is in operation, X constant voltage modules and at least one voltage regulating module are selected and put into operation according to the voltage requirement of the DC direct-mounted energy storage system, where X is less than or equal to N.

[0016] Furthermore,

[0017] The remaining NX constant voltage modules are in a standby state, and the X constant voltage modules are rotated at predetermined time intervals.

[0018] Furthermore,

[0019] In a single constant voltage module, the first battery cluster is connected in parallel with the first half bridge;

[0020] In a single voltage regulating module, the second battery cluster is connected in parallel with the second half bridge; the capacitor C in the LC filter circuit is connected in parallel with the second battery cluster and the second half bridge; the inductor L and the DC pre-charging circuit in the LC filter circuit are connected in series between the second battery cluster and the capacitor C.

[0021] Furthermore,

[0022] A single constant voltage module and a single voltage regulating module are respectively connected to the DC grid by a bypass switch K; the bypass switch is in a normally open state, and when the bypass switch is closed, the corresponding constant voltage module or voltage regulating module is short-circuited and cut out of the DC grid.

[0023] Based on the same inventive concept, the present disclosure also provides a control method for a DC direct-mounted energy storage system, comprising:

[0024] Real-time collection and sorting of the SOC of the first battery cluster in all constant voltage modules;

[0025] According to the voltage requirement of the DC grid, select the number of constant voltage modules and voltage regulating modules to be put into use; the constant voltage modules that are not put into use are used as spare modules;

[0026] The constant voltage module that needs to be put into operation is always turned on through the upper tube of the first half bridge and connected in series to the DC grid; the voltage regulation module that needs to be put into operation is connected in series to the DC grid through PWM control of the second half bridge switch;

[0027] According to the charging and discharging requirements and the SOC of the first battery cluster in all constant voltage modules, the constant voltage modules that have been put into use and the standby modules are switched on and off in rotation at a predetermined time interval.

[0028] Furthermore,

[0029] According to the charging and discharging requirements and the SOC of the first battery cluster in all constant voltage modules, the constant voltage modules that have been put into use and the standby modules are switched in rotation at a predetermined time interval, including:

[0030] According to the charging instruction, the constant voltage module that has been put into use and the standby module with the lowest SOC of the first battery cluster are switched on and off in rotation at a predetermined time interval;

[0031] According to the discharge instruction, the constant voltage module that has been put into use and the standby module with the highest SOC of the first battery cluster are switched on and off in rotation at a predetermined time interval.

[0032] Based on the same inventive concept, the present disclosure also provides a control device for a DC direct-mounted energy storage system, including a SOC real-time acquisition and sorting module, an input quantity selection module, a constant voltage module and a voltage regulation module control module, and a constant voltage module rotation switching module;

[0033] SOC real-time acquisition and sorting module, used for real-time acquisition and sorting of SOC of all constant voltage modules;

[0034] An investment quantity selection module is used to select the number of constant voltage modules and voltage regulating modules that need to be invested according to the voltage demand of the DC power grid;

[0035] The constant voltage module and the voltage regulating module control module are used to connect the constant voltage module that needs to be put into use to the energy storage system through the upper tube of the half-bridge all the time; the voltage regulating module that needs to be put into use is connected to the energy storage system through PWM control of the half-bridge switch;

[0036] The constant voltage module rotation switching module is used to rotate the constant voltage module that has been put into use with the standby module at a predetermined time interval according to the charging and discharging requirements and the SOC of all constant voltage modules.

[0037] Based on the same inventive concept, the present disclosure also provides an electronic device, comprising at least one electrically connected processor and at least one memory, wherein the memory is electrically connected to the processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the control method of the energy storage system as described above.

[0038] Based on the same inventive concept, the present disclosure further provides a computer storage medium, in which computer executable instructions are stored. When the computer executable instructions are executed, any of the aforementioned energy storage system control methods is implemented.

[0039] Compared with the prior art, the present invention has the following advantages:

[0040] In the DC direct-mounted energy storage system of the disclosed embodiment, the majority of constant voltage modules do not need to be equipped with LC filtering circuits and DC pre-charging circuits, and only a small number of voltage regulating modules need to be controlled by PWM, which significantly reduces the switching loss of the system's half-bridge power module, greatly saves circuit costs, and also simplifies the control strategy.

[0041] Other features and advantages of the present disclosure will be described in the following description, and partly become apparent from the description, or be understood by implementing the present disclosure. The purpose and other advantages of the present disclosure can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 The topological structure principle diagram of the existing medium and high voltage DC direct-mounted energy storage system is shown;

[0044] Figure 2 A schematic diagram of a carrier phase-shift pulse width modulation strategy for a half-bridge submodule in an existing energy storage system is shown;

[0045] Figure 3 A topological principle diagram of a DC direct-mounted energy storage system based on an energy storage battery according to an embodiment of the present disclosure is shown;

[0046] Figure 4 A schematic diagram of the voltage compensation principle of the voltage regulating module according to an embodiment of the present disclosure is shown;

[0047] Figure 5 A schematic diagram of a voltage regulation module topology structure according to another embodiment of the present disclosure is shown;

[0048] Figure 6 A schematic diagram of a voltage regulation module topology structure according to another embodiment of the present disclosure is shown;

[0049] Figure 7 A schematic diagram of a voltage regulation module control strategy according to an embodiment of the present disclosure is shown;

[0050] Figure 8 A schematic diagram of a constant voltage module control strategy flow chart according to an embodiment of the present disclosure is shown;

[0051] Fig. 9 A schematic structural diagram of an electronic device according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0053] Figure 3 A topological structure diagram of a DC direct-mounted energy storage system based on an energy storage battery according to an embodiment of the present disclosure is shown, including: N constant voltage modules (low-speed switching modules) and M voltage regulating modules (high-speed switching modules), where N is greater than M (N and M are both natural numbers). As a preferred solution, the value of N should be much greater than M, for example, N is greater than M by an order of magnitude or more.

[0054] N constant voltage modules and M voltage regulating modules are connected in series to a DC power grid.

[0055] In the disclosed embodiment: a single constant voltage module includes a first battery cluster and a first half-bridge; a single voltage regulation module includes a second battery cluster, a DC pre-charging circuit (DC relay, pre-charging resistor R), an LC filter circuit, and a second half-bridge. Both the first half-bridge and the second half-bridge include power electronic switches G1 and G2.

[0056] Before connecting the battery cluster, G1 and G2 are in the closed state, and DC relays K1 and K2 are in the open state. When preparing to connect the battery cluster, K1 is closed first. At this time, the battery cluster charges the capacitor C through the pre-charging resistor R. When the capacitor C voltage is consistent with the battery cluster voltage, K2 is closed, and the battery cluster is connected to the half-bridge. The purpose of the pre-charging circuit is to limit the surge current of the battery cluster charging C. The purpose of the LC circuit is to limit the battery cluster ripple current caused by the switching of the half-bridge module.

[0057] In a single constant voltage module, the first battery cluster is connected in parallel with the first half bridge; in a single voltage regulation module, the second battery cluster is connected in parallel with the second half bridge; the capacitor C in the LC filter circuit is connected in parallel with the second battery cluster and the second half bridge; the inductor L and the DC pre-charging circuit in the LC filter circuit are connected in series between the second battery cluster and the capacitor C.

[0058] For both the constant pressure module and the voltage regulating module, when the upper tube is turned on and the lower tube is locked, it means the module is in the on state; when the upper tube is locked and the lower tube is turned on, it means the module is in the off state (the lower tube is part of the closed loop of the energy storage system).

[0059] As a preferred technical means, the cascade ports of a single constant voltage module and a single voltage regulating module are connected in parallel with a bypass switch K. The bypass switch is in a normally open state. When the bypass switch is closed, the corresponding constant voltage module or voltage regulating module is short-circuited and cut out of the DC power grid.

[0060] As a preferred technical means, a smoothing reactor Lp is connected in series to the positive busbar of the DC grid.

[0061] As a preferred technical means, the constant voltage module and the voltage regulating module also include a fuse F connected in series in the circuit. The fuse F is arranged at the output end of the battery cluster so that the battery cluster has a certain fault current breaking capacity.

[0062] Figure 3 In the illustrated embodiment, among the N constant voltage modules, X modules are always in the on-state, and the remaining NX constant voltage modules are in the off-state (standby state).

[0063] It should be noted that the system voltage of the DC power grid fluctuates to a certain extent, and the voltage of the battery cluster changes with the state of its own remaining power SOC. The higher the SOC value, the higher the battery voltage. Therefore, when designing the system, a certain amount of redundancy needs to be designed for the constant voltage module to ensure that when all constant voltage modules are at the lowest SOC, the total DC voltage is close to the total voltage of the DC system. In other words, among the N constant voltage modules, X modules are always in the input state, and the remaining NX modules are in the cut-out state (standby state), so that they can be rotated regularly (for example, every 10 minutes) to achieve SOC balance of the battery cluster in the system.

[0064] The working principle of the embodiment of the present disclosure is as follows Figure 4 As shown. X constant voltage modules generate a stable reference voltage, and a small number of voltage regulating modules (at least M = 1) generate a variable ripple voltage. The number of constant voltage modules invested is related to their current SOC state. The total voltage of the constant voltage modules invested should be slightly lower than the total system voltage of the DC power grid, and the remaining DC voltage shortage is compensated by the voltage regulating module in real time. That is, by fine-tuning the output voltage of the voltage regulating module, the output power of the entire device can be dynamically adjusted.

[0065] The specific case parameters are as follows:

[0066] Assume that the energy storage system has 4 constant voltage modules and 1 voltage regulating module, and the battery voltage of each module is 1kV.

[0067] 1) Assuming that the system voltage of the DC grid is 4.2kV at this time, if the entire energy storage system is to be charged, the upper tubes of all four constant voltage modules are always turned on to generate a 4kV voltage, and one voltage regulating module is switched on through a half-bridge switch, and the closed-loop control generates a slightly smaller 0.2kV differential voltage.

[0068] 2) Assuming that the DC grid voltage is 3.8kV at this time, if the entire energy storage system is to be charged, the upper tubes of the three constant voltage modules (with the lowest SOC) are always turned on to generate a 3kV voltage, and one voltage regulation module is switched on and off through a half-bridge switch, and the closed-loop control generates a slightly smaller 0.8kV differential voltage.

[0069] At the same time, the four constant voltage modules are rotated at a low speed according to their own SOC status, for example, one group is changed every 10 minutes, and each time the three modules with the lowest SOC are put into the system.

[0070] 3) Assuming that the grid voltage is 4.2kV at this time, if the entire energy storage system is to be discharged, the upper tubes of all four constant voltage modules are always turned on to generate a 4kV voltage, and one voltage regulating module is switched on through a half-bridge switch, and the closed-loop control generates a slightly larger differential voltage of 0.2kV.

[0071] 4) Assuming that the grid voltage is 3.8kV at this time, if the entire energy storage system is to be discharged, the upper tubes of the three constant voltage modules (with the highest SOC) are always turned on to generate a 3kV voltage, and one voltage regulating module is switched on through a half-bridge switch, and the closed-loop control generates a slightly larger 0.8kV differential voltage.

[0072] At the same time, the four constant voltage modules are rotated at a low speed according to their own SOC status, for example, one group is changed every 10 minutes, and each time the three modules with the highest SOC are put into the system.

[0073] As a preferred implementation means, the battery cluster may be composed of energy storage elements such as lithium-ion batteries and supercapacitors.

[0074] As a preferred implementation means, the circuit topology of the voltage regulating module can also be other types of AC / DC or DC / DC converters, such as Figure 5 or Figure 6 shown.

[0075] Since the constant voltage module in the embodiment of the present disclosure does not need to adopt PWM control, there is no need to set an LC filter circuit in the topology of the constant voltage module, and since there is no LC circuit, there is no need to further set a DC pre-charge circuit. Therefore, the hardware cost of the embodiment of the present disclosure will be greatly reduced. At the same time, since the constant voltage module does not need to adopt PWM control, the switching loss of the half-bridge power module of the constant voltage module is significantly reduced. In addition, the PWM control strategy of the DC direct-mounted energy storage system of the embodiment of the present disclosure only needs to be implemented for a small number of voltage regulating modules, which is also much simpler and easier than the control method of the traditional topology structure.

[0076] Based on the same inventive concept, an embodiment of the present disclosure further provides a control method based on the aforementioned DC direct-mounted energy storage system, comprising:

[0077] Real-time collection and sorting of the SOC of the first battery cluster in all constant voltage modules;

[0078] According to the voltage requirement of the DC grid, select the number of constant voltage modules and voltage regulating modules to be put into use; the constant voltage modules that are not put into use are used as spare modules;

[0079] The constant voltage module that needs to be put into operation is always turned on through the upper tube of the half-bridge and connected in series to the DC grid; the voltage regulation module that needs to be put into operation is connected in series to the DC grid through PWM control of the half-bridge switch;

[0080] According to the charging and discharging requirements and the SOC of the first battery cluster in all constant voltage modules, the constant voltage modules that have been put into use and the standby modules are switched on and off in rotation at a predetermined time interval.

[0081] Among them, according to the charging instruction, the constant voltage module that has been put into use and the backup module with the lowest SOC of the first battery cluster are switched on and off at a predetermined time interval; according to the discharging instruction, the constant voltage module that has been put into use and the backup module with the highest SOC of the first battery cluster are switched on and off at a predetermined time interval.

[0082] Among them, the control strategy of the voltage regulation module is as follows Figure 7As shown, the energy storage system control module makes a difference between the reference value I dcref of the energy storage system output current and the currently detected current value I dc, and then generates the duty cycle of the voltage regulation module switch through PI regulation. The duty cycle is compared with the triangular carrier to generate the trigger pulse instructions for the upper and lower tubes of the half-bridge of the voltage regulation module. The reference value I dcref of the energy storage system output current is given by the upper scheduling system or the energy management system. The output DC voltage or output active power of the energy storage system can also be used as the reference value of the control quantity of the half-bridge switch of the voltage regulation module.

[0083] The control strategy of the constant pressure module is as follows Figure 8 shown.

[0084] The energy storage system control module collects and sorts the SOCs of all N constant voltage modules in real time; when receiving a discharge command, the constant voltage module with the highest SOC that needs to be put into use is always turned on through the upper tube of the half-bridge, connected in series to the DC power grid, and the X constant voltage modules that have been put into use are rotated with the backup module with the highest SOC at a predetermined time interval; when receiving a charge command, the constant voltage module with the lowest SOC that needs to be put into use is always turned on through the upper tube of the half-bridge, connected in series to the DC power grid, and the X constant voltage modules that have been put into use are rotated with the backup module with the lowest SOC at a predetermined time interval.

[0085] Through the above strategy, no matter in charging or discharging conditions, the output voltage of the voltage regulating module is lower than that of the constant voltage module. Therefore, the SOC of the voltage regulating module changes more slowly and does not affect the SOC operating range of the constant voltage module.

[0086] Based on the above method, the embodiment of the present disclosure also provides a control device for a DC direct-mounted energy storage system corresponding to the above method, including a SOC real-time acquisition and sorting module, an input quantity selection module, a constant voltage module and a voltage regulation module control module, and a constant voltage module rotation switching module;

[0087] SOC real-time acquisition and sorting module, used for real-time acquisition and sorting of SOC of all constant voltage modules;

[0088] An investment quantity selection module is used to select the number of constant voltage modules and voltage regulating modules that need to be invested according to the voltage demand of the DC power grid;

[0089] The constant voltage module and the voltage regulating module control module are used to connect the constant voltage module that needs to be put into use to the DC grid through the upper tube of the half-bridge all the time; the voltage regulating module that needs to be put into use is connected to the DC grid through PWM control of the half-bridge switch;

[0090] The constant voltage module rotation switching module is used to rotate the constant voltage module that has been put into use with the standby module at a predetermined time interval according to the charging and discharging requirements and the SOC of all constant voltage modules.

[0091] Based on the same inventive concept as the above disclosed content, the present disclosure also provides an electronic device. Fig. 9 As shown, the electronic device of an embodiment of the present disclosure includes at least one electrically connected processor and at least one memory, wherein the memory is electrically connected to the processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the control method of the energy storage system as described above.

[0092] It should be noted that the electrical connection between the above-mentioned units does not necessarily mean the connection between lines. An indirect connection method can be applied to the embodiments of the present disclosure as long as the purpose of the present disclosure is achieved.

[0093] Based on the same inventive concept, the present disclosure also provides a computer storage medium, in which computer executable instructions are stored, and when the computer executable instructions are executed, the aforementioned control method of an energy storage system is implemented.

[0094] Based on the same inventive concept, an embodiment of the present invention further provides a computer program product, which is stored in a storage medium and is executed by at least one processor to implement the various processes of the control method embodiment of the energy storage system as described above, and can achieve the same technical effect. To avoid repetition, it will not be described here.

[0095] Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A DC direct-mounted energy storage system based on energy storage batteries, characterized in that: The energy storage system includes N constant voltage modules and M voltage regulating modules, where N is greater than M, and N and M are natural numbers; N constant voltage modules and M voltage regulating modules are connected in series to the DC grid; The topology of a single constant voltage module is different from that of a single voltage regulating module: The single constant voltage module includes a first battery cluster and a first half bridge; A single voltage regulation module includes a second battery cluster, a DC pre-charging circuit, an LC filtering circuit, and a second half bridge.

2. The energy storage system according to claim 1, characterized in that: When the energy storage system is running, X constant voltage modules and at least one voltage regulating module are selected and put into operation according to the voltage demand, where X is less than or equal to N.

3. The energy storage system according to claim 2, characterized in that: The remaining NX constant voltage modules are in a standby state, and the X constant voltage modules are rotated at a predetermined time interval to achieve SOC balancing control of different cascaded battery clusters.

4. The energy storage system according to claim 1, characterized in that: In a single constant voltage module, the first battery cluster is connected in parallel with the first half bridge; In a single voltage regulating module, the second battery cluster is connected in parallel with the second half bridge; the capacitor C in the LC filter circuit is connected in parallel with the second battery cluster and the second half bridge; the inductor L and the DC pre-charging circuit in the LC filter circuit are connected in series between the second battery cluster and the capacitor C.

5. The energy storage system according to any one of claims 1 to 4, characterized in that: A single constant voltage module and a single voltage regulating module are respectively connected to the DC grid by a bypass switch K; the bypass switch K is in a normally open state; when the bypass switch K is closed, the corresponding constant voltage module or voltage regulating module is short-circuited and cut out of the energy storage system.

6. A control method for a DC direct-mounted energy storage system, characterized in that: The method comprises, Real-time collection and sorting of the SOC of the first battery cluster in all constant voltage modules; According to the voltage requirements of the DC grid, select the number of constant voltage modules and voltage regulating modules to be invested; The constant pressure module that is not put into use is used as a spare module; The constant voltage module that needs to be put into use is always turned on through the upper tube of the first half bridge and connected in series with the direct-hanging energy storage system; the constant voltage module that is not put into use, the lower tube of the first half bridge is always turned on; the voltage regulating module that needs to be put into use is connected in series with the direct-hanging energy storage system through PWM control of the second half bridge switch; the constant voltage module and the voltage regulating module that are not put into use, the lower tube of the second half bridge is always turned on; According to the charging and discharging requirements and the SOC of the first battery cluster in all constant voltage modules, the constant voltage modules that have been put into use and the standby modules are switched on and off in rotation at a predetermined time interval.

7. The control method according to claim 6, characterized in that: According to the charging and discharging requirements and the SOC of the first battery cluster in all constant voltage modules, the constant voltage modules that have been put into use and the standby modules are switched in rotation at a predetermined time interval, including: According to the charging instruction, the constant voltage module that has been put into use and the standby module with the lowest SOC of the first battery cluster are switched on and off in rotation at a predetermined time interval; According to the discharge instruction, the constant voltage module that has been put into use and the standby module with the highest SOC of the first battery cluster are switched on and off in rotation at a predetermined time interval.

8. A control device for a DC direct-mounted energy storage system, characterized in that: The control device includes a SOC real-time acquisition and sorting module, an input quantity selection module, a constant voltage module and a voltage regulation module control module, and a constant voltage module rotation switching module; SOC real-time acquisition and sorting module, used for real-time acquisition and sorting of SOC of all constant voltage modules; An investment quantity selection module is used to select the number of constant voltage modules and voltage regulating modules that need to be invested according to the voltage demand of the DC power grid; The constant voltage module and the voltage regulating module control module are used to connect the constant voltage module that needs to be put into use to the energy storage system through the first half-bridge upper tube, and the voltage regulating module that needs to be put into use is connected to the energy storage system through PWM control of the second half-bridge switch; The constant voltage module rotation switching module is used to rotate the constant voltage module that has been put into use with the standby module at a low speed at a predetermined time interval according to the charging and discharging requirements and the SOC of all constant voltage modules.

9. An electronic device, characterized in that: The electronic device comprises at least one processor and at least one memory electrically connected; the memory is electrically connected to the processor; The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the control method as described in any one of claims 6 or 7.

10. A computer storage medium, characterized in that: The computer storage medium stores computer executable instructions, which, when executed, implement the manufacturing method according to any one of claims 6 or 7.

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