A direct current power grid real-time distributed optimal power flow control method and system

Abstract

The present application relates to the field of direct current power grid control, in particular to a kind of direct current power grid real-time distributed optimal power flow control method and system;The output voltage and output current of local direct current power supply are obtained;According to the average voltage error of output voltage, nominal voltage, local and neighbor consistency control deviation calculation;Integral control is carried out to average voltage error to generate voltage integral control signal;According to voltage integral control signal and neighbor voltage integral control signal, update local consistency control deviation and feedback;The difference between output current and virtual current signal is proportionally integrated controlled;Virtual current signal is updated and feedbacked;According to current proportional integral control signal, neighbor current proportional integral control signal, local and neighbor output voltage, generate and output voltage reference value.The present application can realize global optimal power flow control without line impedance parameter, and can actively adjust average voltage to improve voltage stability margin.

Description

Technical Field

[0001] This invention relates to the field of DC power grid control, and specifically to a real-time distributed optimal power flow control method and system for DC power grids. Background Technology

[0002] DC power grids are widely used for large-scale DC power supply and load connection due to their simple structure and the fact that they do not require frequency synchronization and reactive power regulation. How to reduce the operating losses of lines and power sources within the power regulation range and improve the overall energy utilization efficiency of DC power grids is an urgent need to achieve the economical operation of DC power grids.

[0003] Existing optimal power flow control methods for DC power grids are mainly divided into two categories. The first category is offline optimization methods, which predict the load demand and power adjustment range of each node in the system, and use optimization tools such as linear programming and particle swarm optimization to calculate the reference values ​​of bus voltage or power offline, which are then executed by the underlying power supply control. Although the principle of this type of method is mature, it is heavily dependent on the accuracy of prediction. Once the load fluctuates or the power supply is subjected to external disturbances, its optimality cannot be guaranteed. The second category is real-time distributed control methods, which use the concept of feedback control to enable the grid to dynamically adjust the bus voltage according to load changes, effectively avoiding the bottleneck of dependence on prediction accuracy in offline methods, and have received widespread attention in recent years.

[0004] However, existing control methods have the following problems: First, most methods only consider power balance constraints, ignoring the grid topology constraints between power sources and loads. This makes it impossible to effectively model and optimize line losses, limiting energy utilization efficiency. Second, while some methods that consider topology constraints (such as consistency control and subgradient descent) can optimize losses, their algorithm solution process heavily relies on the precise impedance parameters of the DC grid. In actual operation, factors such as line aging, temperature changes, and network topology reconfiguration make it difficult to accurately obtain impedance parameters, which also change dynamically. Once the parameters have errors, existing control methods that rely on precise models will not be able to converge to the true global optimal operating point. Third, the voltage constraints of existing optimization problems only focus on the steady-state safety range. The average voltage level passively depends on the initial value of the system operation and lacks active adjustment means. When encountering large disturbances, voltage drops or exceeding limits are prone to occur, significantly reducing the voltage stability margin of the DC grid. Summary of the Invention

[0005] To address the problems mentioned in the prior art, this invention proposes a real-time distributed optimal power flow control method and system for DC power grids, which minimizes operating losses to improve the energy utilization efficiency of DC power grids, and simultaneously achieves active regulation of the average voltage of the grid to enhance the voltage stability margin of DC power grids.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention proposes a real-time distributed optimal power flow control method for a DC power grid, wherein the DC power grid includes multiple DC power controllers interconnected via a communication network, and includes the following steps: S1. Obtain the output voltage and output current of the local DC power supply; S2. Calculate the local average voltage error based on the output voltage, the preset DC grid nominal voltage, the local consistency control deviation, and the neighbor consistency control deviation received from one or more neighboring nodes. S3. Perform integral control on the local average voltage error to generate a voltage integral control signal; S4. Update the local consistency control deviation based on the voltage integral control signal and the neighbor voltage integral control signal received from one or more neighboring nodes to obtain the updated signal of the local consistency control deviation; feed the updated signal of the local consistency control deviation back to S2 for calculation in the next control cycle. S5. Perform proportional-integral control on the difference between the output current and the introduced virtual current signal to generate a current proportional-integral control signal. S6. Update the virtual current signal according to the gradient of the local cost function and the preset current operation constraints to obtain the updated signal of the virtual current signal; feed back the updated signal of the virtual current signal to S5 for calculation in the next control cycle. S7. Generate a voltage reference value based on the current proportional-integral control signal, the neighbor current integral control signal received from one or more neighboring nodes, the local output voltage, and the neighbor output voltage received from one or more neighboring nodes, and output the voltage reference value to control the local DC power supply.

[0007] As a further improvement of the present invention, the formula for calculating the local average voltage error in S2 is as follows:

[0008] In the formula: This represents the local average voltage error. The nominal voltage of the DC power grid; This is the output voltage of the local DC power supply; To control deviations for local consistency; To control deviations for neighbor consistency, Represents the neighbor node number; For local DC power supply and neighboring nodes The communication link weight is a positive number.

[0009] As a further improvement of the present invention, the calculation formula for integral control of the local average voltage error in S3 is as follows:

[0010] In the formula: This is the voltage integral control signal; Voltage integral control gain; This represents the local average voltage error.

[0011] As a further improvement of the present invention, the calculation formula for updating the local consistency control deviation in S4 is as follows:

[0012] In the formula: This serves as an update signal for local consistency control deviations; Update the gain for consistency; This is the voltage integral control signal; This is the neighbor voltage integral control signal.

[0013] As a further improvement of the present invention, the calculation formula for proportional-integral control of the difference between the output current and the introduced virtual current signal in step S5 is as follows:

[0014] In the formula: This is the proportional-integral control signal for the current. The gain is controlled by the current integral. This refers to the output current of the local DC power supply. This is a virtual current signal.

[0015] As a further improvement of the present invention, the calculation formula for updating the virtual current signal in S6 is as follows:

[0016] In the formula: This is the update signal for the virtual current signal; Update the gain for virtual current; To find the minimum value function, This is a function to find the maximum value. This represents the lower bound of the operating output current. Represents the upper limit of the operating output current; This represents the gradient of the local cost function. Represents the local cost function; This is a virtual current signal; This is the proportional-integral control signal for the current.

[0017] As a further improvement of the present invention, the local cost function Let be a convex function, used to characterize the operating losses of the local DC power supply, and its calculation formula is as follows:

[0018] In the formula: , , This represents the parameters for calculating power generation costs, and is taken as positive values. The gradient of the local cost function is calculated as follows:

[0019] In the formula: It is a symbolic function.

[0020] As a further improvement to the present invention, the formula for calculating the voltage reference value in step S7 is as follows:

[0021] In the formula: This is the voltage reference value; Update the gain for the voltage reference; This is the voltage integral control signal; This represents the local average voltage error. For local DC power supply and neighboring nodes The weight of the communication link; This is the output voltage of the local DC power supply; This is the proportional-integral control signal for the current. Output voltage to neighbors The proportional-integral control signal is for the neighboring current.

[0022] This invention proposes a real-time distributed optimal power flow control system for DC power grids, comprising: The acquisition module is used to acquire the output voltage and output current of the local DC power supply; The average voltage error calculation module is used to calculate the local average voltage error based on the output voltage, the preset DC grid nominal voltage, the local consistency control deviation, and the neighbor consistency control deviation received from one or more neighbor nodes. The voltage integral control signal module is used to perform integral control on the local average voltage error and generate a voltage integral control signal. The consistency control deviation update module is used to update the local consistency control deviation based on the voltage integral control signal and the neighbor voltage integral control signal received from one or more neighboring nodes, to obtain the update signal of the local consistency control deviation; and feeds back the update signal of the local consistency control deviation to the average voltage error calculation module for calculation in the next control cycle. The current proportional-integral control module is used to perform proportional-integral control on the difference between the output current and the introduced virtual current signal, and generate a current proportional-integral control signal. The virtual current update module is used to update the virtual current signal according to the gradient of the local cost function and the preset current operation constraints to obtain the updated signal of the virtual current signal; and feeds back the updated signal of the virtual current signal to the current proportional-integral control module for calculation in the next control cycle. The voltage reference output module is used to generate a voltage reference value based on the current proportional-integral control signal, the neighbor current integral control signal received from one or more neighboring nodes, the local output voltage, and the neighbor output voltage received from one or more neighboring nodes, and output the voltage reference value to control the local DC power supply.

[0023] This invention proposes a real-time distributed optimal power flow control device for a DC power grid, comprising a processor and a memory, wherein the processor executes a computer program stored in the memory to implement the real-time distributed optimal power flow control method for the DC power grid as described above.

[0024] Compared with the prior art, the present invention achieves the following technical effects: This invention transforms the optimization of output current into tracking and controlling the virtual current by introducing a virtual current signal. In subsequent steps, the virtual current is updated based on the gradient of the local cost function. The entire process does not require any line impedance parameters to participate in the calculation. In the process of generating the voltage reference value, this invention removes the dependence on the electrical network parameters of the DC system. It can directly use the manually set communication network weights to find the operating point with the minimum real loss of the entire network, which greatly improves the control robustness of the system in the face of unknown or time-varying operating conditions such as line aging and network reconstruction.

[0025] This invention constructs an active average voltage regulation closed loop. By calculating the local average voltage error, the control target of the global average voltage can be decomposed into a distributed consistency error that can be calculated locally by each node. Step S3 ensures that the average voltage error returns to zero in steady state through integral control. Consistency updates make the voltage integral control signal more consistent, which can adjust the average voltage to the nominal value and ensure that the voltage can remain stable after the system is disturbed, significantly improving the voltage stability margin of the DC grid. In addition, each DC power controller of this invention only needs to acquire local information and neighbor information received from neighboring nodes through the communication network, and can complete the calculation locally in each control cycle without any centralized optimization solver or global data acquisition. The distributed architecture gives the system good flexibility and scalability, which can adapt to the actual plug-and-play operation of the DC grid, while avoiding the risk of global failure caused by a single point of failure in centralized control. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall process of the present invention; Figure 2 This is a schematic diagram of the DC power grid structure of the present invention; Figure 3 For the present invention A flowchart illustrating the method for using a DC power supply; Figure 4 This is a schematic diagram of the DC power supply output voltage response curve using an existing method. Figure 5 This is a schematic diagram of the DC power supply output voltage response curve of the present invention; Figure 6 This is a schematic diagram comparing the average voltage response curves of the present invention and existing methods. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0028] See Figure 1 This embodiment proposes a real-time distributed optimal power flow control method for a DC power grid, wherein the DC power grid includes multiple DC power controllers interconnected via a communication network, and includes the following steps: S1. Obtain the output voltage and output current of the local DC power supply; S2. Calculate the local average voltage error based on the output voltage, the preset DC grid nominal voltage, the local consistency control deviation, and the neighbor consistency control deviation received from one or more neighboring nodes. S3. Perform integral control on the local average voltage error to generate a voltage integral control signal; S4. Update the local consistency control deviation based on the voltage integral control signal and the neighbor voltage integral control signal received from one or more neighboring nodes to obtain the updated signal of the local consistency control deviation; feed the updated signal of the local consistency control deviation back to S2 for calculation in the next control cycle. S5. Perform proportional-integral control on the difference between the output current and the introduced virtual current signal to generate a current proportional-integral control signal. S6. Update the virtual current signal according to the gradient of the local cost function and the preset current operation constraints to obtain the updated signal of the virtual current signal; feed back the updated signal of the virtual current signal to S5 for calculation in the next control cycle. S7. Generate a voltage reference value based on the current proportional-integral control signal, the neighbor current integral control signal received from one or more neighboring nodes, the local output voltage, and the neighbor output voltage received from one or more neighboring nodes, and output the voltage reference value to control the local DC power supply.

[0029] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments: like Figure 2 As shown, the DC power grid system used in this embodiment includes multiple DC power sources, multiple controllers, an electrical network, and a communication network. The DC power sources represent power generation devices located near the transmission and distribution network, commonly such as photovoltaic power plants and wind farms—distributed energy sources. These DC power sources are connected in parallel through the electrical network to collectively supply power to the load. Each DC power source is equipped with a DC power source controller, which acts as the control unit for the DC power source and executes the control method proposed in this invention. The various DC power source controllers communicate with each other through a communication network (…). Figure 2 (Represented by dashed lines) Information exchange takes place. For each DC power source, any DC power source with which it can directly exchange information via the communication network is defined as its neighbor node, thus forming a distributed communication topology. It should be noted that the communication topology is independent of the electrical network topology, and the weight of the communication link does not need to be set based on the impedance parameters of the electrical network.

[0030] Step 1, such as Figure 3 As shown, in one specific embodiment, the DC power controller performs real-time measurements using voltage and current sensors installed in the DC power supply. The voltage sensor is preferably a Hall effect voltage sensor or a resistive voltage divider circuit, and the current sensor is preferably a Hall effect current sensor or a shunt. The DC power controller performs measurements at the beginning of each control cycle to obtain the current time. The local output voltage of a DC power supply and local output current .

[0031] Step 2: The DC power controller calculates the local average voltage error based on the local output voltage acquired in Step 1, the preset nominal DC grid voltage, the local consistency control deviation, and the neighbor consistency control deviation received from one or more neighboring nodes via the communication network. Those skilled in the art should understand that the nominal DC grid voltage is a preset rated voltage value, and the specific value is determined based on the actual engineering application scenario.

[0032] The formula for calculating the local average voltage error is as follows:

[0033] In the formula: This represents the local average voltage error. The nominal voltage of the DC power grid; This is the output voltage of the local DC power supply; To control deviations for local consistency; To control deviations for neighbor consistency, Represents the neighbor node number; For local DC power supply and neighboring nodes The communication link weight is a positive number.

[0034] Step 3: The DC power supply controller performs integral control on the local average voltage error calculated in Step 2, generating a voltage integral control signal. Specifically, the calculation formula is as follows:

[0035] In the formula: This is the voltage integral control signal; This is for voltage integral control gain.

[0036] The physical significance of introducing integral control in this embodiment is that, as long as the local average voltage error is not zero, the integrator will continue to accumulate and continuously adjust the voltage integral control signal until the local average voltage error returns to zero. Therefore, under steady-state conditions, the local average voltage error is, i.e. This indicates that the system's average voltage is controlled at the nominal value, achieving zero-error control. This step, through integral action, gives the system the ability to actively pull the average voltage back to the nominal value, significantly improving the system's voltage recovery capability and stability margin after encountering large disturbances.

[0037] Step 4: The DC power controller updates the local consistency control deviation based on the voltage integral control signal generated in Step 3 and the neighbor voltage integral control signals received from one or more neighboring nodes through the communication network. The updated local consistency control deviation is then fed back to the calculation for the next control cycle in Step 2. Specifically, this update process is performed according to the following formula:

[0038] In the formula: This serves as an update signal for local consistency control deviations; Update the gain for consistency; This is the neighbor voltage integral control signal.

[0039] This step synchronizes the voltage integral control signals of all nodes. Its purpose is to make the voltage integral control signals of each node gradually become consistent through information exchange between neighboring nodes. When the voltage integral control signals of all nodes become the same, combined with the calculation formula of the voltage integral control signal in step three, it can be seen that the local average voltage error of all nodes tends to zero, thereby ensuring that the control target of average voltage is achieved.

[0040] Step 5: The DC power controller performs proportional-integral control based on the difference between the local output current acquired in Step 1 and the introduced virtual current signal, generating a current proportional-integral control signal. The calculation formula is as follows:

[0041] In the formula: This is the proportional-integral control signal for the current. The gain is controlled by the current integral. This refers to the output current of the local DC power supply. This is a virtual current signal.

[0042] It should be noted that in a DC power grid, the output current of each DC power source is determined by the system power flow distribution, mainly depending on the local output voltage, neighboring output voltages, and line impedance parameters. Therefore, it is not possible to directly give a current command like controlling the voltage. Thus, this embodiment introduces a virtual current signal, enabling the output current to track the virtual current, ensuring that the output current is equal to the virtual current signal. This allows subsequent steps to indirectly achieve optimal allocation of the actual output current by updating the virtual current without involving any line impedance parameters.

[0043] Step Six: The DC power controller updates the virtual current signal based on the gradient of the local cost function and the preset current operating constraints, so that the virtual current signal changes along the direction of gradient descent of the local cost function within the current operating constraint range. The calculation formula is as follows:

[0044] In the formula: This is the update signal for the virtual current signal; Update the gain for virtual current; To find the minimum value function, This is a function to find the maximum value. This represents the lower bound of the operating output current. Represents the upper limit of the operating output current; This represents the gradient of the local cost function. Represents the local cost function; This is a virtual current signal; This is the proportional-integral control signal for the current.

[0045] This embodiment uses a minimum value function and a maximum value function to jointly construct a current operation constraint, ensuring that the updated virtual current is always within the allowable operating range of the DC power supply, thus preventing the equipment from operating beyond its limits.

[0046] Local cost function in the example Let be a convex function, used to characterize the operating losses of the local DC power supply, and its calculation formula is as follows:

[0047] In the formula: , , This represents the parameters for calculating power generation costs. It is a normal value and can be calibrated based on the actual operating loss characteristics of the DC power supply.

[0048] The gradient of the local cost function is calculated as follows:

[0049] In the formula: It is a symbolic function.

[0050] In this embodiment, the calculation of the local cost function and gradient relies solely on the locally acquired output current and voltage, without involving any electrical network parameters such as the DC power grid's line impedance and topology. This significantly improves the robustness and environmental adaptability of the control method. The updated virtual current signal is fed back to the current proportional-integral control calculation in step five, participating in the calculation of the next control cycle, thus forming a closed loop consisting of current proportional-integral control and virtual current update.

[0051] Step 7: The DC power controller uses the current proportional-integral control signal, the neighbor current integral control signal received from one or more neighboring nodes, the local output voltage, and the neighbor output voltage received from one or more neighboring nodes to generate a voltage reference value. The calculation formula is as follows:

[0052] In the formula: This is the voltage reference value; Update the gain for the voltage reference; This is the voltage integral control signal; This represents the local average voltage error. For local DC power supply and neighboring nodes The weight of the communication link; This is the output voltage of the local DC power supply; This is the proportional-integral control signal for the current. Output voltage to neighbors The proportional-integral control signal is for the neighboring current.

[0053] In this embodiment, the voltage reference value simultaneously addresses two control objectives: maintaining the average voltage stability of the entire grid and minimizing operating losses. This ensures economical grid operation while guaranteeing voltage safety and stability. The generated voltage reference value is input to the underlying control of the DC power supply, driving it to adjust its output voltage and thus altering the power flow distribution across the entire grid, completing one control cycle. After one control cycle is completed, the system returns to the status acquisition stage in step one to begin data acquisition and calculation for the next control cycle. This process is repeated continuously to achieve real-time distributed optimal power flow control of the DC grid.

[0054] like Figure 4 As shown in the figure, the output voltage response curve of the DC power supply using the existing method can be seen that before the load changes in 2 seconds, the existing method can ensure that the output voltage of all DC power supplies is maintained within the safe range of 0.95 pu to 1.05 pu. However, when the load on DC power supplies 1, 2, 3, and 4 increases by 1.4 pu, 0.5 pu, 0.5 pu, and 1 pu respectively in 2 seconds, due to the lack of active voltage regulation, the output voltage of DC power supply 2 will exceed the safe threshold of 1.05 pu, thus disrupting the voltage stability of the DC system.

[0055] like Figure 5 As shown in the figure, the method of the present invention can ensure that the output voltage of all DC power supplies remains within the safe range of 0.95 pu to 1.05 pu before the load changes in 2 seconds. Furthermore, at 0 seconds, due to the active voltage regulation mechanism of the method, the output voltage of each DC power supply will actively decrease to the per-unit value. When the load on DC power supplies 1, 2, 3, and 4 increases by 1.4 pu, 0.5 pu, 0.5 pu, and 1 pu respectively in 2 seconds, the output voltage of all DC power supplies can still be maintained within the safe threshold range, ensuring the voltage stability of the DC system.

[0056] like Figure 6 As shown, the average voltage response of existing methods is strongly correlated with the initial values ​​of the output voltages of each DC power supply, and lacks effective adjustment methods. In contrast, the proposed method can actively achieve average voltage regulation, ensuring a larger voltage stability margin, and can still maintain the voltage stability of the DC system after being disturbed.

[0057] Referring to Table 1, the loss of the DC system after it enters steady state is compared with the optimal theoretical loss obtained by the centralized optimization method. It can be seen that the steady-state loss of the proposed method is almost the same as the optimal theoretical loss, with a relative error of only 0.000011527%.

[0058] Table 1

[0059] Based on the same inventive concept, this embodiment of the invention also provides a real-time distributed optimal power flow control system for DC power grids. Since the principle of solving the problem by this real-time distributed optimal power flow control system for DC power grids is similar to that of the aforementioned real-time distributed optimal power flow control method for DC power grids, the implementation of this real-time distributed optimal power flow control system for DC power grids can refer to the implementation of the real-time distributed optimal power flow control method for DC power grids, and the repeated parts will not be described again.

[0060] In specific implementation, the DC power grid real-time distributed optimal power flow control system provided in this embodiment of the invention specifically includes: The acquisition module is used to acquire the output voltage and output current of the local DC power supply; The average voltage error calculation module is used to calculate the local average voltage error based on the output voltage, the preset DC grid nominal voltage, the local consistency control deviation, and the neighbor consistency control deviation received from one or more neighbor nodes. The voltage integral control signal module is used to perform integral control on the local average voltage error and generate a voltage integral control signal. The consistency control deviation update module is used to update the local consistency control deviation based on the voltage integral control signal and the neighbor voltage integral control signal received from one or more neighboring nodes, to obtain the update signal of the local consistency control deviation; and feeds back the update signal of the local consistency control deviation to the average voltage error calculation module for calculation in the next control cycle. The current proportional-integral control module is used to perform proportional-integral control on the difference between the output current and the introduced virtual current signal, and generate a current proportional-integral control signal. The virtual current update module is used to update the virtual current signal according to the gradient of the local cost function and the preset current operation constraints to obtain the updated signal of the virtual current signal; and feeds back the updated signal of the virtual current signal to the current proportional-integral control module for calculation in the next control cycle. The voltage reference output module is used to generate a voltage reference value based on the current proportional-integral control signal, the neighbor current integral control signal received from one or more neighboring nodes, the local output voltage, and the neighbor output voltage received from one or more neighboring nodes, and output the voltage reference value to control the local DC power supply.

[0061] Accordingly, this embodiment of the invention also provides a real-time distributed optimal power flow control device for a DC power grid, including a processor and a memory, wherein the processor executes a computer program stored in the memory to implement the real-time distributed optimal power flow control method for a DC power grid as provided in this embodiment of the invention.

[0062] For more detailed information on the above methods, please refer to the relevant content disclosed in the foregoing embodiments, which will not be repeated here.

[0063] Accordingly, embodiments of the present invention also provide a computer-readable storage medium for storing a computer program, wherein the computer program, when executed by a processor, implements the above-described real-time distributed optimal power flow control method for DC power grids provided in embodiments of the present invention.

[0064] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems, devices, and storage media disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0065] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0066] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0067] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0068] The present invention provides a detailed description of the real-time distributed optimal power flow control method, system, equipment, and storage medium for DC power grids. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, those skilled in the art will recognize that there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A real-time distributed optimal power flow control method for a DC power grid, wherein the DC power grid includes multiple DC power controllers interconnected via a communication network, characterized in that, Includes the following steps: S1. Obtain the output voltage and output current of the local DC power supply; S2. Calculate the local average voltage error based on the output voltage, the preset DC grid nominal voltage, the local consistency control deviation, and the neighbor consistency control deviation received from one or more neighboring nodes. S3. Perform integral control on the local average voltage error to generate a voltage integral control signal; S4. Update the local consistency control deviation based on the voltage integral control signal and the neighbor voltage integral control signal received from one or more neighboring nodes to obtain the updated signal of the local consistency control deviation; feed the updated signal of the local consistency control deviation back to S2 for calculation in the next control cycle. S5. Perform proportional-integral control on the difference between the output current and the introduced virtual current signal to generate a current proportional-integral control signal. S6. Update the virtual current signal according to the gradient of the local cost function and the preset current operation constraints to obtain the updated signal of the virtual current signal; feed back the updated signal of the virtual current signal to S5 for calculation in the next control cycle. S7. Generate a voltage reference value based on the current proportional-integral control signal, the neighbor current integral control signal received from one or more neighboring nodes, the local output voltage, and the neighbor output voltage received from one or more neighboring nodes, and output the voltage reference value to control the local DC power supply.

2. The method for real-time distributed optimal power flow control of a DC power grid according to claim 1, characterized in that, The formula for calculating the local average voltage error in S2 is as follows: In the formula: This represents the local average voltage error. The nominal voltage of the DC power grid; This is the output voltage of the local DC power supply; To control deviations for local consistency; To control deviations for neighbor consistency, Represents the neighbor node number; For local DC power supply and neighboring nodes The communication link weight is a positive number.

3. The real-time distributed optimal power flow control method for a DC power grid according to claim 1, characterized in that, The formula for integral control of the local average voltage error in S3 is as follows: In the formula: This is the voltage integral control signal; Voltage integral control gain; This represents the local average voltage error.

4. The real-time distributed optimal power flow control method for a DC power grid according to claim 1, characterized in that, The calculation formula for updating the local consistency control deviation in S4 is as follows: In the formula: This serves as an update signal for local consistency control deviations; Update the gain for consistency; This is the voltage integral control signal; This is the neighbor voltage integral control signal.

5. The real-time distributed optimal power flow control method for a DC power grid according to claim 1, characterized in that, The formula for proportional-integral control of the difference between the output current and the introduced virtual current signal in S5 is as follows: In the formula: This is the proportional-integral control signal for the current. The gain is controlled by the current integral. This refers to the output current of the local DC power supply. This is a virtual current signal.

6. The real-time distributed optimal power flow control method for a DC power grid according to claim 1, characterized in that, The calculation formula for updating the virtual current signal in S6 is as follows: In the formula: This is the update signal for the virtual current signal; Update the gain for virtual current; To find the minimum value function, This is a function to find the maximum value. This represents the lower bound of the operating output current. Represents the upper limit of the operating output current; This represents the gradient of the local cost function. Represents the local cost function; This is a virtual current signal; This is the proportional-integral control signal for the current.

7. The real-time distributed optimal power flow control method for a DC power grid according to claim 6, characterized in that, The local cost function Let be a convex function, used to characterize the operating losses of the local DC power supply, and its calculation formula is as follows: In the formula: , , This represents the parameters for calculating power generation costs, and is taken as positive values. The gradient of the local cost function is calculated as follows: In the formula: It is a symbolic function.

8. The real-time distributed optimal power flow control method for a DC power grid according to claim 1, characterized in that, The formula for calculating the generated voltage reference value in S7 is as follows: In the formula: This is the voltage reference value; Update the gain for the voltage reference; This is the voltage integral control signal; This represents the local average voltage error. For local DC power supply and neighboring nodes The weight of the communication link; This is the output voltage of the local DC power supply; This is the proportional-integral control signal for the current. Output voltage to neighbors The proportional-integral control signal is for the neighboring current.

9. A real-time distributed optimal power flow control system for a DC power grid, characterized in that, include: The acquisition module is used to acquire the output voltage and output current of the local DC power supply; The average voltage error calculation module is used to calculate the local average voltage error based on the output voltage, the preset DC grid nominal voltage, the local consistency control deviation, and the neighbor consistency control deviation received from one or more neighbor nodes. The voltage integral control signal module is used to perform integral control on the local average voltage error and generate a voltage integral control signal. The consistency control deviation update module is used to update the local consistency control deviation based on the voltage integral control signal and the neighbor voltage integral control signal received from one or more neighboring nodes, to obtain the update signal of the local consistency control deviation; and feeds back the update signal of the local consistency control deviation to the average voltage error calculation module for calculation in the next control cycle. The current proportional-integral control module is used to perform proportional-integral control on the difference between the output current and the introduced virtual current signal, and generate a current proportional-integral control signal. The virtual current update module is used to update the virtual current signal according to the gradient of the local cost function and the preset current operation constraints to obtain the updated signal of the virtual current signal; and feeds back the updated signal of the virtual current signal to the current proportional-integral control module for calculation in the next control cycle. The voltage reference output module is used to generate a voltage reference value based on the current proportional-integral control signal, the neighbor current integral control signal received from one or more neighboring nodes, the local output voltage, and the neighbor output voltage received from one or more neighboring nodes, and output the voltage reference value to control the local DC power supply.

10. A real-time distributed optimal power flow control device for a DC power grid, characterized in that, It includes a processor and a memory, wherein the processor executes a computer program stored in the memory to implement the real-time distributed optimal power flow control method for DC power grids as described in any one of claims 1 to 7.

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