A method, system, medium, and equipment for reducing losses in a DC microgrid system.

Abstract

This invention discloses a loss reduction method, system, medium, and equipment for a DC microgrid system, relating to the field of DC microgrid optimization control technology. This invention transforms the loss reduction target corresponding to line loss, neglecting line resistance, into a loss reduction control target that is the difference between the grid connection point voltage of each distributed energy source and the output voltage of each distributed energy source, plus the sum of the differences between the grid connection point voltages of each distributed energy source. By injecting disturbances into the output voltage of each distributed energy source, and since the DC bus can be equivalent to a large capacitor, the change in the grid connection point voltage of the distributed energy source can be ignored. Therefore, the line resistance from each distributed energy source to the grid connection point can be self-identified by the ratio of the change in the output voltage to the change in the output current of each distributed energy source. Furthermore, the grid connection point voltage of each distributed energy source can be self-identified based on its output voltage and output current. Finally, based on the loss reduction control target, rapid loss reduction can be achieved through PI control.

Description

Technical Field

[0001] This invention relates to the field of DC microgrid optimization control technology, and in particular to a loss reduction method, system, medium, and equipment for DC microgrid systems. Background Technology

[0002] Generally, network loss is a key indicator for measuring the economic efficiency of microgrid systems. Line loss, which characterizes energy loss during power transmission in a microgrid, is a significant component of network loss. Excessive line loss degrades voltage quality, wastes energy, and jeopardizes the economic viability of the microgrid system. More seriously, it can lead to overheating and insulation damage in the lines. Therefore, reducing line loss to improve the power quality of DC microgrids is essential for building economical, safe, and high-quality DC microgrids.

[0003] The control objectives of a DC microgrid system include precise regulation of the bus voltage and precise power allocation to each unit as required. Achieving the former objective is beneficial for maintaining the stability of the microgrid system, while achieving the latter objective is closely related to the economics of the microgrid system. Specifically, to achieve different economic objectives of the DC microgrid system, such as minimizing energy consumption, minimizing system cost, and minimizing line loss, it is necessary to control the power allocation method of each distributed energy source in the DC microgrid.

[0004] In existing technologies, when the economic objective is to minimize the line loss of a DC microgrid system, the focus is often on solving a single optimization problem related to the line loss of the microgrid system. The optimization problem of the microgrid system with respect to line loss is usually a relatively complex non-convex optimization problem, so intelligent algorithms such as ant colony and particle swarm optimization are generally used to solve it.

[0005] However, existing methods for solving microgrid system optimization problems using intelligent algorithms are complex and have a slow response speed for loss reduction. Summary of the Invention

[0006] Therefore, it is necessary to provide a loss reduction method, system, medium, and equipment for DC microgrid systems to address the aforementioned technical problems.

[0007] The present invention adopts the following technical solution:

[0008] This invention provides a loss reduction method for a DC microgrid system, which includes a DC bus and multiple distributed energy sources connected to the DC bus. The invention aims to minimize the difference between the grid connection point voltage and the output voltage of each distributed energy source, as well as the sum of the differences between the grid connection point voltages of each distributed energy source. Then, based on the ratio of the output voltage change to the output current change of each distributed energy source under disturbance voltage, the line resistance from each distributed energy source to the grid connection point is determined. Subsequently, based on the output voltage, output current, and line resistance of each distributed energy source to the grid connection point, the grid connection point voltage of each distributed energy source is determined. Finally, based on the loss reduction control objective, the grid connection point voltage, and the output voltage of each distributed energy source, a PI control is used to determine the corresponding loss reduction correction amount for each distributed energy source to control its output.

[0009] This invention provides a loss reduction system for a DC microgrid system, the DC microgrid system including a DC bus and multiple distributed energy sources connected to the DC bus; the system includes:

[0010] The target construction module is used to minimize the difference between the grid connection voltage of each distributed energy source and the output voltage of each distributed energy source, and the sum of the differences between the grid connection voltages of each distributed energy source as the loss reduction control target;

[0011] The resistance identification module is used to determine the line resistance from each distributed energy source to the grid connection point based on the ratio of the change in output voltage to the change in output current of each distributed energy source under the disturbance of the disturbance voltage.

[0012] The voltage identification module is used to determine the grid connection point voltage of each distributed energy source based on the output voltage of each distributed energy source, the output current of each distributed energy source, and the line resistance from each distributed energy source to the grid connection point.

[0013] The control module is used to determine the corresponding control quantity of each distributed energy source based on the loss reduction control target, the grid connection point voltage of each distributed energy source, and the output voltage of each distributed energy source, so as to control the output of each distributed energy source through PI control.

[0014] The present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the loss reduction method of the above-described DC microgrid system.

[0015] The present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the loss reduction method of the DC microgrid system described above.

[0016] The above-mentioned at least one technical solution adopted in this invention can achieve the following beneficial effects:

[0017] This invention transforms the loss reduction target corresponding to line loss into a loss reduction control target that neglects line resistance, using the difference between the grid connection point voltage of each distributed energy source and the output voltage of each distributed energy source, and the sum of the differences between the grid connection point voltages of each distributed energy source. Only the grid connection point voltage of each distributed energy source is unknown. To address this, this invention injects disturbances into the output voltage of each distributed energy source. Since the DC bus of the DC microgrid system can be equivalent to a large capacitor, the change in the grid connection point voltage of the distributed energy source can be ignored. Therefore, the line resistance from each distributed energy source to the grid connection point can be self-identified by the ratio of the change in the output voltage to the change in the output current of each distributed energy source. Furthermore, the grid connection point voltage of each distributed energy source can be self-identified based on its output voltage and output current. Finally, based on the loss reduction control target, rapid loss reduction can be achieved through PI control, reducing the complexity of loss reduction and improving the response speed. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 A schematic flowchart of a loss reduction method for a DC microgrid system provided by the present invention;

[0020] Figure 2 A schematic diagram of a DC microgrid system provided by the present invention;

[0021] Figure 3 A schematic diagram of the control block for a collaborative loss reduction method for a DC microgrid system provided by the present invention;

[0022] Figure 4 This is a schematic diagram of a loss reduction system for a DC microgrid system provided by the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] Currently, existing DC microgrid loss reduction technologies mainly suffer from the following two problems:

[0025] (1) Existing loss reduction technologies have a slow response speed. The system optimization problem of line loss is usually a relatively complex non-convex optimization problem, which is generally solved by intelligent algorithms such as ant colony and particle swarm optimization. The solution is complex and the loss reduction speed is slow.

[0026] (2) Existing loss reduction technologies lack synergy. They mostly focus on solving a single optimization problem related to system line loss, making it difficult to take into account the precise regulation of bus voltage. Therefore, existing methods have poor control quality and are difficult to achieve coordinated multi-objective optimization of the system.

[0027] To address the aforementioned issues, this invention is based on a distributed collaborative control architecture for DC microgrids, which mainly includes a voltage PI controller (voltage controller) and a power PI controller (loss reduction controller). The former is used to regulate the bus voltage, while the latter is used to control the power to minimize the network loss (mainly line loss) of the DC microgrid system.

[0028] This invention proposes a loss reduction method for DC microgrids, which can simply and quickly reduce system line losses and improve system economy. Furthermore, this invention can coordinately regulate system voltage, power, and line losses based on a distributed cooperative control architecture. Its synergy lies in the fact that this invention can achieve precise regulation of the bus voltage while reducing losses, maintaining system resilience and improving operational quality. In other words, this invention can quickly and effectively achieve coordinated loss reduction in microgrids while ensuring precise bus voltage regulation.

[0029] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] Figure 1 This is a schematic diagram of a loss reduction method for a DC microgrid system according to the present invention. The DC microgrid system includes a DC bus and multiple distributed energy sources connected to the DC bus; specifically, it includes the following steps:

[0031] S101: The loss reduction control objective is to minimize the difference between the grid connection voltage of each distributed energy source and the output voltage of each distributed energy source, and the sum of the differences between the grid connection voltages of each distributed energy source.

[0032] S102: Determine the line resistance from each distributed energy source to the grid connection point based on the ratio of the change in output voltage to the change in output current of each distributed energy source under the disturbance voltage.

[0033] S103: Determine the grid connection point voltage of each distributed energy source based on the output voltage of each distributed energy source, the output current of each distributed energy source, and the line resistance from each distributed energy source to the grid connection point.

[0034] S104: Based on the loss reduction control target, the grid connection point voltage of each distributed energy source, and the output voltage of each distributed energy source, the loss reduction correction amount corresponding to each distributed energy source is determined by PI control in order to control the output of each distributed energy source.

[0035] This invention primarily targets DC microgrid systems with a ring architecture. Figure 2 This is a schematic diagram of a DC microgrid system according to the present invention. Figure 2 middle R i Distributed energy i Line resistance to grid connection point, R ii-1 Distributed energy i- 1. Grid connection points and distributed energy i Extensive research has shown that the line resistance between grid connection points is crucial, and ring-architecture DC microgrids are widely applicable to practical physical systems. In this structure, all distributed energy sources are controllable, and a two-layer control system guides the output of each distributed energy source to achieve economic operation goals. Therefore, the controlled object in this invention is the grid-connected converter of the distributed energy source.

[0036] The control objectives of a DC microgrid system primarily include loss reduction control. In one or more embodiments of the present invention, it may also include bus voltage control, which corresponds to a loss reduction controller and a bus voltage controller, respectively.

[0037] First, regarding loss reduction control, such as Figure 2 As shown, Indicates the first The line loss expression for the bus connection point voltage (or grid connection point voltage) of a distributed energy source, based on the energy transmission in a DC microgrid system, can be determined by the following formula:

[0038] .

[0039] in, For line losses in DC microgrid systems, The number of distributed energy sources. Distributed energy i The grid connection point voltage, Distributed energy i The output voltage, Distributed energy i Line resistance to grid connection point, Distributed energy j The grid connection point voltage, Distributed energy i Grid connection points and distributed energy j Line resistance between grid connection points.

[0040] Based on this line loss expression, the target for minimizing line loss can be determined: .

[0041] To minimize line losses in a DC microgrid system, the line loss expression can be observed. and Since all are constants, in one or more embodiments of the present invention, the line resistance constant in the line loss expression of the loss reduction target can be discarded, and the target can be transformed into a loss reduction control objective that minimizes the difference between the voltage at each distributed energy grid connection point and the output voltage of each distributed energy source, and the sum of the differences between the voltages at each distributed energy grid connection point: .

[0042] Ideally, for any distributed energy source i The loss reduction control objective can be expressed as: .

[0043] However, in reality, energy transfer in a DC microgrid system relies on voltage difference. The current flowing through the cables will inevitably lead to a certain degree of voltage difference, which means... , It is physically impossible to achieve, as there is no absolute steady state for the loss reduction controller, but its output loss reduction component can help reduce network losses.

[0044] For distributed energy sources, obtaining their grid connection point voltage is difficult, especially for microgrid systems with multiple distributed energy sources. Measuring the grid connection point voltage of each distributed energy source would increase system construction costs. To address this, this invention employs a grid connection point voltage self-identification method, as follows:

[0045] based on Figure 2 The DC microgrid system structure shown is suitable for distributed energy resources. exist The following relationships exist at any given time:

[0046] .

[0047] in, Distributed energy exist Output current at any moment Distributed energy i The line resistance to the grid connection point is only It is an unknown quantity.

[0048] At this time, distributed energy The output voltage is injected with a disturbance, the magnitude of which is The duration of the disturbance is ,go through The magnitude of the subsequent perturbation returns to zero. Therefore, in The following relationships exist at any given time:

[0049] .

[0050] Combining the above two equations, we have the following relationship:

[0051] .

[0052] Research indicates that the DC bus of a DC microgrid system can be considered equivalent to a large capacitor. For this large capacitor, distributed energy... disturbance It can be ignored, therefore distributed energy The voltage change at the grid connection point is negligible. Therefore, the line resistance from each distributed energy source to the grid connection point can be determined using the following formula: (Formula omitted for brevity)

[0053] ;

[0054] in, Distributed energy i exist t Output voltage at any given time Distributed energy i exist Output voltage at any given time Distributed energy i exist The output current at any given time.

[0055] The above formula only includes local voltage and current information; therefore, it can be used to relatively easily identify the line resistance from each distributed energy source to the grid connection point. Based on this, according to It can realize the self-identification of the grid connection point voltage of each distributed energy source.

[0056] Therefore, based on the loss reduction control target, the grid connection point voltage of each distributed energy source, and the output voltage of each distributed energy source, the loss reduction correction amount corresponding to each distributed energy source can be determined using the following formula based on PI control:

[0057] .

[0058] in, Distributed energy i The corresponding loss reduction adjustment is used to reduce line loss. This is the proportional gain in the loss reduction controller. This is the integral coefficient in the loss reduction controller.

[0059] Based on this, the control law corresponding to each distributed energy source can be determined according to the loss reduction correction amount, so as to correct the control command of each distributed energy source, control the output of each distributed energy source, and reduce line loss.

[0060] Furthermore, in one or more embodiments of the present invention, bus voltage control can be considered simultaneously with loss reduction. For each distributed energy source in a DC microgrid, its grid connection point bus voltage cannot be completely regulated to be consistent. If the grid connection point voltages of all distributed energy sources are the same, energy flow between the distributed energy sources in the microgrid cannot be achieved. Therefore, analogous to the concept of a voltage central point in a traditional power system, the concept of a bus voltage observer is proposed in a DC microgrid.

[0061] Specifically, for each distributed energy source, the observed bus voltage of its neighboring distributed energy sources can be obtained first. The output voltage of the current distributed energy source is then used as its initial observed bus voltage. The error between the observed bus voltage of the current distributed energy source and that of its neighboring distributed energy sources is determined. Based on this error, the compensation for the output voltage of the current distributed energy source is determined through integration, thereby determining the observed bus voltage of the current distributed energy source. The formula is as follows:

[0062] .

[0063] In the formula, Indicates in Time of the first Bus voltage observations for distributed energy resources. Indicates in Time of the first Bus voltage observations of distributed energy sources; distributed energy sources Indicating with distributed energy The communication neighbor distributed energy (i.e., neighbor nodes). Indicates in Distributed energy at all times The output voltage, Distributed energy With distributed energy Communication coefficients between them.

[0064] When the The first distributed energy and the first When the observed bus voltage values ​​of all distributed energy sources are consistent, the above equation converges, and it can be considered that the bus voltage has been observed. Therefore, The meaning is: in the first The bus voltage observation value of a distributed energy source. This can be considered as the central point voltage.

[0065] Therefore, the objective of bus voltage control is to ensure that the observed bus voltage values ​​at each central point, i.e., each distributed energy source, are near their rated values, as shown in the following formula: .

[0066] In the formula, This indicates the rated value of the bus voltage.

[0067] Based on this, minimizing the difference between the observed bus voltage and the rated value of the distributed energy source can be used as the bus voltage control target. The voltage correction amount corresponding to each distributed energy source can be determined by PI control according to the bus voltage control target using the following formula:

[0068] .

[0069] In the formula, This is the voltage correction value output by the voltage controller, used to achieve bus voltage control. This refers to the proportional coefficient in the voltage controller. This refers to the integral coefficient in the voltage controller.

[0070] Therefore, in one or more embodiments of the present invention, when controlling the output of each distributed energy source, a PI controller can be used to achieve coordinated loss reduction control through the following formula: .

[0071] In the formula, Distributed energy i The control quantity. Ultimately, this will be superimposed on the distributed energy voltage control command to guide the output of the distributed energy. Figure 3 This is a schematic diagram of the control block of a collaborative loss reduction method for a DC microgrid system according to the present invention.

[0072] Thus, the collaborative loss reduction control of DC microgrids, namely bus voltage control and loss reduction control, has been completed. It should be noted that the collaborative loss reduction control of DC microgrids proposed in this invention is all distributed control. For bus voltage control, only the bus voltage observation information of neighboring nodes is required; for loss reduction control, only the grid connection point voltage information of neighboring nodes is required. It is not necessary to obtain the global information of the DC microgrid system, and the system construction cost is low.

[0073] based on Figure 1The loss reduction method for the DC microgrid system shown in this invention omits line resistance and transforms the loss reduction target corresponding to line loss into a loss reduction control target consisting of the difference between the grid connection point voltage of each distributed energy source and the output voltage of each distributed energy source, and the sum of the differences between the grid connection point voltages of each distributed energy source. Only the grid connection point voltage of each distributed energy source is unknown. To address this, this invention injects disturbances into the output voltage of each distributed energy source. Since the DC bus of the DC microgrid system can be equivalent to a large capacitor, the change in the grid connection point voltage of the distributed energy source can be ignored. Therefore, the line resistance from each distributed energy source to the grid connection point can be self-identified by the ratio of the change in the output voltage to the change in the output current of each distributed energy source. Furthermore, the grid connection point voltage of each distributed energy source can be self-identified based on its output voltage and output current. Finally, based on the loss reduction control target, rapid loss reduction can be achieved through PI control, reducing the complexity of loss reduction and improving the response speed.

[0074] This invention employs a PI control method, eliminating the need to solve any complex non-convex optimization problems and enabling rapid loss reduction. This invention improves the synergy of loss reduction in DC microgrids, utilizes a low-cost distributed collaborative control strategy, and can also address system bus voltage regulation, ensuring system control quality.

[0075] When applying the loss reduction method for DC microgrid systems provided by this invention, it is not necessary to consider... Figure 1 The steps shown are executed in sequence. The specific execution order of each step can be determined as needed, and this invention does not impose any restrictions on it.

[0076] The above describes a loss reduction method for a DC microgrid system provided by one or more embodiments of the present invention. Based on the same idea, the present invention also provides a corresponding loss reduction system for a DC microgrid system, such as... Figure 4 As shown.

[0077] Figure 4 This invention provides a schematic diagram of a loss reduction system for a DC microgrid system. The DC microgrid system includes a DC bus and multiple distributed energy sources connected to the DC bus; the system includes:

[0078] The target construction module 201 is used to minimize the difference between the grid connection voltage of each distributed energy source and the output voltage of each distributed energy source, and the sum of the differences between the grid connection voltages of each distributed energy source as the loss reduction control target.

[0079] The resistance identification module 202 is used to determine the line resistance from each distributed energy source to the grid connection point based on the ratio of the change in output voltage of each distributed energy source to the change in output current of each distributed energy source under the disturbance of the disturbance voltage.

[0080] The voltage identification module 203 is used to determine the grid connection point voltage of each distributed energy source based on the output voltage of each distributed energy source, the output current of each distributed energy source, and the line resistance from each distributed energy source to the grid connection point.

[0081] The control module 204 is used to determine the corresponding control quantity of each distributed energy source in order to control the output of each distributed energy source by means of PI control, based on the loss reduction control target, the grid connection point voltage of each distributed energy source and the output voltage of each distributed energy source.

[0082] Specific limitations regarding the loss reduction system for DC microgrid systems can be found in the limitations on loss reduction methods for DC microgrid systems described above, and will not be repeated here. Each module in the aforementioned loss reduction system for DC microgrid systems can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0083] The present invention also provides a computer-readable storage medium storing a computer program that can be used to execute the above-described... Figure 1 The proposed loss reduction method for DC microgrid systems.

[0084] This invention also provides a structural diagram. At the hardware level, the computer device includes a processor, an internal bus, a network interface, memory, and non-volatile memory, and may also include other hardware required for various operations. The processor reads the corresponding computer program from the non-volatile memory into memory and then executes it to achieve the above-mentioned functions. Figure 1 The proposed loss reduction method for DC microgrid systems.

[0085] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0086] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this invention.

Claims

1. A loss reduction method for a DC microgrid system, characterized in that, The DC microgrid system includes a DC bus and multiple distributed energy sources connected to the DC bus; the method includes: The loss reduction control objective is to minimize the difference between the grid connection voltage of each distributed energy source and the output voltage of each distributed energy source, as well as the sum of the differences between the grid connection voltages of each distributed energy source. The line resistance from each distributed energy source to the grid connection point is determined based on the ratio of the change in output voltage to the change in output current of each distributed energy source under the disturbance voltage. The grid connection point voltage of each distributed energy source is determined based on the output voltage, output current, and line resistance from each distributed energy source to the grid connection point. Based on the loss reduction control target, the grid connection point voltage of each distributed energy source, and the output voltage of each distributed energy source, the loss reduction correction amount corresponding to each distributed energy source is determined by the following formula based on PI control: ； in, Distributed energy i The corresponding loss reduction correction amount, The number of distributed energy sources. This is the proportional gain in the loss reduction controller. This is the integral coefficient in the loss reduction controller. Distributed energy i The grid connection point voltage, Distributed energy j The grid connection point voltage, Distributed energy i The output voltage.

2. The loss reduction method for a DC microgrid system as described in claim 1, characterized in that, The loss reduction control objective, which aims to minimize the difference between the grid connection voltage of each distributed energy source and the output voltage of each distributed energy source, as well as the sum of the differences between the grid connection voltages of each distributed energy source, specifically includes: The loss reduction control objective is to minimize the difference between the voltage at each distributed energy source's grid connection point and the output voltage of each distributed energy source, as well as the sum of the differences between the voltages at each distributed energy source's grid connection point, using the following formula: ； in, The number of distributed energy sources. Distributed energy i The grid connection point voltage, Distributed energy i The output voltage, Distributed energy j The grid connection point voltage.

3. The loss reduction method for a DC microgrid system as described in claim 1, characterized in that, The determination of the line resistance from each distributed energy source to the grid connection point based on the ratio of the output voltage change to the output current change of each distributed energy source under disturbance voltage includes: To mitigate the output voltage disturbance of each distributed energy source, the line resistance from each distributed energy source to the grid connection point is determined using the following formula: (Formula provided in the original text). ； in, Distributed energy i Line resistance to grid connection point Distributed energy i exist t Output voltage at any given time Distributed energy i exist Output voltage at any given time Distributed energy i exist t Output current at any moment Distributed energy i exist Output current at any moment The duration of the disturbance.

4. The loss reduction method for a DC microgrid system as described in claim 1, characterized in that, The method further includes: For each distributed energy source, obtain the bus voltage observations of its neighboring distributed energy sources; The output voltage of the distributed energy source is used as the initial bus voltage observation value of the distributed energy source, and the error between the bus voltage observation value of the distributed energy source and the bus voltage observation value of the neighboring distributed energy source is determined. The compensation for the output voltage of the distributed energy source is determined by integrating the error, thereby determining the observed value of the bus voltage of the distributed energy source. The bus voltage control objective is to minimize the difference between the observed bus voltage and the rated value of the distributed energy source. Based on the bus voltage control objective, the voltage correction amount corresponding to each distributed energy source is determined by PI control. The control of the output of each distributed energy source specifically includes: Based on the sum of the voltage correction and the loss reduction correction, the control quantity corresponding to each distributed energy source is determined. The control quantity of each distributed energy source is then superimposed onto the voltage control command of each distributed energy source to control the output of each distributed energy source.

5. A loss reduction system for a DC microgrid system, characterized in that, The DC microgrid system includes a DC bus and multiple distributed energy sources connected to the DC bus; the system includes: The target construction module is used to minimize the difference between the grid connection voltage of each distributed energy source and the output voltage of each distributed energy source, and the sum of the differences between the grid connection voltages of each distributed energy source as the loss reduction control target; The resistance identification module is used to determine the line resistance from each distributed energy source to the grid connection point based on the ratio of the change in output voltage to the change in output current of each distributed energy source under the disturbance of the disturbance voltage. The voltage identification module is used to determine the grid connection point voltage of each distributed energy source based on the output voltage of each distributed energy source, the output current of each distributed energy source, and the line resistance from each distributed energy source to the grid connection point. The control module is used to determine the corresponding loss reduction correction amount for each distributed energy source based on PI control using the following formula, according to the loss reduction control target, the grid connection point voltage of each distributed energy source, and the output voltage of each distributed energy source: ； in, Distributed energy i The corresponding loss reduction correction amount, The number of distributed energy sources. This is the proportional gain in the loss reduction controller. This is the integral coefficient in the loss reduction controller. Distributed energy i The grid connection point voltage, Distributed energy j The grid connection point voltage, Distributed energy i The output voltage.

6. A computer-readable storage medium, characterized in that, The storage medium stores a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 4.

7. A computer device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the method as described in any one of claims 1 to 4.

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