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

Abstract

This disclosure provides a DC direct-connected energy storage system and its control method, apparatus, equipment, and storage medium. The method includes a DC direct-connected energy storage system based on energy storage batteries. The energy storage system includes N constant-voltage modules and M voltage-regulating modules, where N is much larger than M, and N and M are natural numbers. The N constant-voltage modules and M voltage-regulating modules are connected in series to a DC power grid. The topology of a single constant-voltage module differs from that of a single voltage-regulating module: a single constant-voltage module includes a first battery cluster and a first half-bridge; a single voltage-regulating module includes a second battery cluster, a DC pre-charge circuit, an LC filter circuit, and a second half-bridge. In the DC direct-connected energy storage system of this disclosure, the majority of constant-voltage modules do not require LC filter circuits and DC pre-charge circuits; only a small number of voltage-regulating modules need PWM control, which reduces switching losses, improves switching efficiency, saves circuit costs, and simplifies the control strategy.

Description

Technical Field

[0001] This disclosure belongs to the field of DC power transmission technology, and in particular relates to a DC direct-connected energy storage system and its control method, device, equipment and storage medium. Background Technology

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

[0003] Configuring energy storage devices in DC power grids can enhance the system's regulation capabilities and support the efficient utilization of a high proportion of new energy sources.

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

[0005] Figure 1 The topology shown employs a carrier phase-shifting pulse width modulation strategy. During steady-state operation, each half-bridge submodule has two operating states: the upper transistor is on and the lower transistor is off, indicating module activation; the upper transistor is off and the lower transistor is on, indicating module deactivation. The specific control strategy for the half-bridge submodule is as follows: Figure 2 As shown.

[0006] Figure 2 The control strategy shown suffers from significant losses when the switching frequency of the half-bridge submodule is high, and each half-bridge submodule requires an additional LC filter circuit (e.g., Figure 1 (As shown in the diagram) to eliminate the battery's oscillating ripple current, which increases circuit complexity and hardware cost. Summary of the Invention

[0007] To address the aforementioned issues, this disclosure provides a DC direct-connected energy storage system and its control method, which can significantly reduce the switching losses of the half-bridge power module, while reducing the LC filter circuit and DC pre-charge circuit required for most modules, thereby improving the system's conversion efficiency and reducing the overall circuit cost.

[0008] The preferred approach adopted in this disclosure is as follows:

[0009] A DC direct-connected 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 power grid;

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

[0012] A 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-charge circuit, an LC filter circuit, and a second half-bridge.

[0014] Furthermore,

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

[0016] Furthermore,

[0017] The remaining NX constant voltage modules are in standby mode, 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-charge circuit in the LC filter circuit are connected in series between the second battery cluster and the capacitor C.

[0021] Furthermore,

[0022] Each constant voltage module and each voltage regulating module is connected to the DC grid via a bypass switch K. The bypass switch is normally open. When the bypass switch is closed, the corresponding constant voltage module or voltage regulating module is short-circuited out of the DC grid.

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

[0024] The SOC of the first battery cluster in all constant voltage modules is collected and sorted in real time.

[0025] Based on the voltage requirements of the DC power grid, select the number of constant voltage modules and voltage regulating modules to be put into operation; the constant voltage modules that are not put into operation are used as backup modules.

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

[0027] Based on 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 operation and the backup modules are switched on and off at predetermined time intervals.

[0028] Furthermore,

[0029] Based on 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 operation and the backup modules are switched on and off at predetermined time intervals, including:

[0030] According to the charging command, the constant voltage module that has been put into operation and the backup module with the lowest SOC of the first battery cluster are switched on and off at a predetermined time interval.

[0031] According to the discharge command, the constant voltage module that has been put into operation and the backup module with the highest SOC of the first battery cluster are switched on and off at predetermined time intervals.

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

[0033] The SOC real-time acquisition and sorting module is used to acquire and sort the SOC of all constant voltage modules in real time.

[0034] The quantity selection module is used to select the number of constant voltage modules and voltage regulating modules to be put into operation based on the voltage requirements of the DC power grid.

[0035] The constant voltage module and voltage regulation module control module are used to keep the constant voltage module that needs to be put into operation always on through the upper half-bridge MOSFET and connected in series with the energy storage system; the voltage regulation module that needs to be put into operation is connected in series with 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 activated constant voltage modules with the standby modules at predetermined time intervals based on charging and discharging requirements and the SOC of all constant voltage modules.

[0037] Based on the same inventive concept, this disclosure also provides an electronic device including at least one processor and at least one memory electrically connected to the processor, wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the control method of the energy storage system as described above.

[0038] Based on the same inventive concept, this disclosure also provides a computer storage medium storing computer-executable instructions, which, when executed, implement the control method of any of the aforementioned energy storage systems.

[0039] Compared with the prior art, this disclosure has the following advantages:

[0040] In the DC direct-connected energy storage system of this disclosure embodiment, the majority of constant voltage modules do not require LC filter circuits and DC pre-charge circuits. Only a small number of voltage regulating modules need to be controlled by PWM, which significantly reduces the switching losses of the half-bridge power modules in the system, greatly saves circuit costs, and simplifies the control strategy.

[0041] Other features and advantages of this disclosure will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the disclosure. The objects and other advantages of this disclosure may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 The schematic diagram of the topology of an existing medium- and high-voltage DC direct-connected energy storage system is shown.

[0044] Figure 2 This diagram illustrates the carrier phase-shift pulse width modulation strategy of a half-bridge submodule in an existing energy storage system.

[0045] Figure 3 A topology diagram of a DC-DC direct-connected energy storage system based on an embodiment of the present disclosure is shown.

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

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

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

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

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

[0051] Figure 9 A schematic diagram of the structure of an electronic device according to an embodiment of the present disclosure is shown. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0053] Figure 3 A topology diagram of a DC-DC direct-connected 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), wherein N is greater than M (N and M are both natural numbers). As a preferred option, 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 the DC power grid.

[0055] In this embodiment of the disclosure: a single constant voltage module includes a first battery cluster and a first half-bridge; a single voltage regulating module includes a second battery cluster, a DC pre-charge circuit (DC relay, pre-charge 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 off state, and DC relays K1 and K2 are in the off state. When preparing to connect the battery cluster, K1 is closed first. At this time, the battery cluster charges capacitor C through the pre-charge resistor R. When the voltage of capacitor C matches the voltage of the battery cluster, K2 is closed, thus completing the connection of the battery cluster to the half-bridge. The purpose of the pre-charge circuit is to limit the inrush current of the battery cluster charging C. The purpose of the LC circuit is to limit the ripple current of the battery cluster 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 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-charge circuit in the LC filter circuit are connected in series between the second battery cluster and the capacitor C.

[0058] Both the constant pressure module and the voltage regulating module are in the engaged state when the upper tube is on and the lower tube is off, and in the disengaged state when the upper tube is off and the lower tube is on (the lower tube is part of the closed loop of the energy storage system).

[0059] As a preferred technical approach, a bypass switch K is connected in parallel to the cascade ports of each individual constant voltage module and each individual voltage regulating module. The bypass switch is normally open; when the bypass switch is closed, the corresponding constant voltage module or voltage regulating module is short-circuited out of the DC power grid.

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

[0061] As a preferred technical approach, both the constant voltage module and the voltage regulating module also include a fuse F connected in series in the circuit. By installing the fuse F at the output terminal of the battery cluster, the battery cluster gains a certain fault current breaking capacity.

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

[0063] It is important to note that the system voltage of a DC grid fluctuates, and the battery cluster voltage changes with its State of Charge (SOC); the higher the SOC, the higher the battery voltage. Therefore, in system design, the constant voltage modules need to have a certain amount of redundancy to ensure that when all constant voltage modules have the lowest SOC, the total DC voltage is close to the total voltage of the DC system. In other words, of the N constant voltage modules, X modules are always in operation, while the remaining NX modules are in standby mode, allowing for periodic (e.g., rotating every 10 minutes) switching to achieve SOC balancing of the battery clusters in the system.

[0064] The working principle of the embodiments disclosed herein is as follows: Figure 4 As shown, a stable reference voltage is generated by X constant voltage modules, while a varying ripple voltage is generated by a small number of voltage regulating modules (minimum M = 1). The number of constant voltage modules engaged is related to their current state of charge (SOC), ensuring that the total voltage of the engaged constant voltage modules is slightly lower than the total system voltage of the DC grid. The remaining DC voltage deficit is compensated in real time by the voltage regulating modules. In other words, the output power of the entire device can be dynamically adjusted by fine-tuning the output voltage of the voltage regulating modules.

[0065] The specific parameters for this case are as follows:

[0066] Assume 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 the DC grid system voltage is 4.2kV, if the entire energy storage system is to be charged, the upper tubes of all four constant voltage modules will always be on, generating a 4kV voltage. One voltage regulating module will be switched on and off through a half-bridge switch, and the closed-loop control will generate a differential voltage of slightly less than 0.2kV.

[0068] 2) Assuming the DC grid voltage is 3.8kV, if the entire energy storage system is to be charged, the upper tubes of the three constant voltage modules (lowest SOC) will always be on, generating a 3kV voltage. One voltage regulating module will be switched on and off through a half-bridge switch, and the closed-loop control will generate a differential voltage of slightly less than 0.8kV.

[0069] Meanwhile, the four constant voltage modules rotate slowly according to their own SOC status, for example, every 10 minutes, and each rotation selects the three modules with the lowest SOC to be put into the system.

[0070] 3) Assuming the grid voltage is 4.2kV, if the entire energy storage system is to be discharged, the upper tubes of all four constant voltage modules will always be on, generating a 4kV voltage. One voltage regulating module will be switched on and off through a half-bridge switch, and the closed-loop control will generate a differential voltage slightly greater than 0.2kV.

[0071] 4) Assuming 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) will always be on, generating a 3kV voltage. One voltage regulating module will be switched on and off through a half-bridge switch, and the closed-loop control will generate a differential voltage slightly greater than 0.8kV.

[0072] Meanwhile, the four constant voltage modules rotate slowly according to their own SOC status, for example, every 10 minutes, and each rotation selects the three modules with the highest SOC to be put into the system.

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

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

[0075] Since the constant voltage module in this embodiment does not require PWM control, an LC filter circuit is not needed in the constant voltage module topology, and since there is no LC circuit, there is no need to further set up a DC precharge circuit. Therefore, the hardware cost of the embodiments of this disclosure is significantly reduced. At the same time, since the constant voltage module does not require PWM control, the switching losses of the constant voltage module half-bridge power module are significantly reduced. In addition, the PWM control strategy of the DC direct-connected energy storage system in this embodiment only needs to be implemented for a small number of voltage regulation modules, which is much simpler and easier than the control method of traditional topologies.

[0076] Based on the same inventive concept, embodiments of this disclosure also provide a control method based on the aforementioned DC direct-connected energy storage system, comprising:

[0077] The SOC of the first battery cluster in all constant voltage modules is collected and sorted in real time.

[0078] Based on the voltage requirements of the DC power grid, select the number of constant voltage modules and voltage regulating modules to be put into operation; the constant voltage modules that are not put into operation are used as backup modules.

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

[0080] Based on 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 operation and the backup modules are switched on and off at predetermined time intervals.

[0081] Specifically, according to the charging command, the constant voltage module that has been put into operation 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 command, the constant voltage module that has been put into operation and the backup module with the highest SOC of the first battery cluster are switched on and off at a predetermined time interval.

[0082] The control strategy of the voltage regulation module is as follows: Figure 7As shown, the energy storage system control module calculates the difference between the reference value Idcref of the energy storage system output current and the currently detected current value Idc, and then uses this difference to generate the duty cycle of the voltage regulator module switch through PI control. This duty cycle is compared with a triangular carrier wave to generate trigger pulse commands for the upper and lower transistors of the voltage regulator module's half-bridge. The reference value Idcref of the energy storage system output current is given by the upper-level dispatch system or energy management system. The output DC voltage or output active power of the energy storage system can also be used as the control reference value for the voltage regulator module's half-bridge switch.

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

[0084] The energy storage system control module collects and sorts the SOC of all N constant voltage modules in real time. When a discharge command is received, the constant voltage module with the highest SOC that needs to be put into operation is kept on through the upper half-bridge diode and connected in series with the DC grid. The X constant voltage modules that have been put into operation are rotated with the backup module with the highest SOC at predetermined time intervals. When a charging command is received, the constant voltage module with the lowest SOC that needs to be put into operation is kept on through the upper half-bridge diode and connected in series with the DC grid. The X constant voltage modules that have been put into operation are switched and rotated with the backup module with the lowest SOC at predetermined time intervals.

[0085] Using the above strategies, the output voltage of the voltage regulator module is lower than that of the constant voltage module, regardless of whether it is charging or discharging. Therefore, the SOC of the voltage regulator module changes more slowly and does not affect the SOC operating range of the constant voltage module.

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

[0087] The SOC real-time acquisition and sorting module is used to acquire and sort the SOC of all constant voltage modules in real time.

[0088] The quantity selection module is used to select the number of constant voltage modules and voltage regulating modules to be put into operation based on the voltage requirements of the DC power grid.

[0089] The constant voltage module and voltage regulation module control module are used to keep the constant voltage module that needs to be put into operation always on through the upper half-bridge MOSFET and connected in series with the DC power grid; the voltage regulation module that needs to be put into operation is connected in series with the DC power grid through PWM control of the half-bridge switch.

[0090] The constant voltage module rotation switching module is used to rotate the activated constant voltage modules with the standby modules at predetermined time intervals based on charging and discharging requirements and the SOC of all constant voltage modules.

[0091] Based on the same inventive concept as the above-disclosed content, this disclosure also provides an electronic device. For example... Figure 9 As shown, the electronic device of this disclosure includes at least one processor and at least one memory electrically connected to the processor. The memory is electrically connected to the processor, wherein the memory stores instructions executable by the at least one processor, which are executed by the at least one processor to enable the at least one processor to perform 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. The indirect connection method can be applied to the embodiments of this disclosure as long as it achieves the purpose of this disclosure.

[0093] Based on the same inventive concept, this disclosure also provides a computer storage medium storing computer-executable instructions, which, when executed, implement the aforementioned control method for an energy storage system.

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

[0095] Although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A DC-DC direct-connected energy storage system based on a battery, characterized in that, The energy storage system includes N constant-pressure 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 power grid; The topology of a single constant voltage module differs from that of a single voltage regulating module: A single constant voltage module includes a first battery cluster and a first half-bridge; the first battery cluster and the first half-bridge are connected in parallel; A single voltage regulation module includes a second battery cluster, a DC pre-charge circuit, an LC filter circuit, and a second half-bridge; the second battery cluster and the second half-bridge are connected in parallel; 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 in the LC filter circuit and the DC pre-charge circuit are connected in series between the second battery cluster and the capacitor C.

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 to be put into operation according to 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 standby mode. The X constant voltage modules are rotated at predetermined time intervals to achieve SOC equalization control of different cascaded battery clusters.

4. The energy storage system according to any one of claims 1-3, characterized in that, Each constant voltage module and each voltage regulating module is connected to the DC grid by a bypass switch K; the bypass switch K is normally open; when the bypass switch K is closed, the corresponding constant voltage module or voltage regulating module is short-circuited out of the energy storage system.

5. A control method for a DC-DC direct-connected energy storage system, applicable to the DC-DC direct-connected energy storage system based on an energy storage battery as described in any one of claims 1-4, characterized in that, The method includes, The SOC of the first battery cluster in all constant voltage modules is collected and sorted in real time. Based on the voltage requirements of the DC power grid, select the number of constant voltage modules and voltage regulation modules to be installed; The unused constant voltage module is used as a backup module; The constant voltage module that needs to be put into operation is always connected to the direct-connected energy storage system through the upper tube of the first half-bridge; the constant voltage module that is not put into operation has the lower tube of the first half-bridge always connected; the voltage regulating module that needs to be put into operation is connected to the direct-connected energy storage system through the second half-bridge switch controlled by PWM; the constant voltage module and voltage regulating module that are not put into operation have the lower tube of the second half-bridge always connected. Based on 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 operation and the backup modules are switched on and off at predetermined time intervals.

6. The control method according to claim 5, characterized in that, Based on 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 operation and the backup modules are switched on and off at predetermined time intervals, including: According to the charging command, the constant voltage module that has been put into operation 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 discharge command, the constant voltage module that has been put into operation and the backup module with the highest SOC of the first battery cluster are switched on and off at predetermined time intervals.

7. A control device for a DC-DC direct-connected energy storage system, used to execute the control method for a DC-DC direct-connected energy storage system as described in claim 5 or 6, characterized in that, The control device includes a real-time SOC acquisition and sorting module, an input quantity selection module, a constant pressure module and a voltage regulation module control module, and a constant pressure module rotation and switching module. The SOC real-time acquisition and sorting module is used to acquire and sort the SOC of all constant voltage modules in real time. The quantity selection module is used to select the number of constant voltage modules and voltage regulating modules to be put into operation based on the voltage requirements of the DC power grid. The constant voltage module and voltage regulation module control module are used to keep the constant voltage module that needs to be put into operation always on through the upper tube of the first half-bridge and connected in series with the energy storage system; the voltage regulation module that needs to be put into operation is connected in series with the energy storage system through PWM control of the second half-bridge switch. The constant voltage module rotation switching module is used to perform low-speed rotation between the activated constant voltage modules and the standby modules at predetermined time intervals, based on charging and discharging requirements and the SOC of all constant voltage modules.

8. An electronic device, characterized in that, The electronic device includes at least one processor and at least one memory electrically connected to each other; the memory is electrically connected to the processor. The memory stores instructions that can be executed by the at least one processor, which, when executed by the at least one processor, enables the at least one processor to perform the control method as described in any one of claims 5 or 6.

9. A computer storage medium, characterized in that, The computer storage medium stores computer-executable instructions, which, when executed, implement the manufacturing method as described in any one of claims 5 or 6.

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