Bipolar DC power distribution network comprehensive voltage regulation and control method based on multi-dimensional flexible interconnection equipment

Abstract

The invention discloses a bipolar DC power distribution network comprehensive voltage regulation and control method based on a multi-dimensional flexible interconnection device, and the method comprises the steps: 1, constructing the multi-dimensional flexible interconnection device with a multi-dimensional power regulation capability, and proposes a bipolar DC power distribution network-oriented comprehensive voltage regulation and control method based on the multi-dimensional flexible interconnection device; 2, designing and analyzing a topological structure and a power transmission model of the flexible interconnection equipment, and revealing a multi-dimensional adjustment characteristic of the flexible interconnection equipment; 3, according to the bipolar DC power distribution network model, obtaining photovoltaic renewable energy output data, DC load data and multi-dimensional flexible interconnection equipment parameter data in the power distribution network; and 4, considering the cooperation of the bipolar flexible interconnection equipment and other adjusting equipment, and establishing a comprehensive voltage regulation and control model by minimizing the operation cost and the voltage out-of-limit cost. According to the invention, controllable transmission of power can be realized, the voltage quality of the system is effectively improved, and the operation loss and voltage unbalance degree of the power distribution network are reduced.

Description

Technical Field

[0001] This invention belongs to the field of power system operation optimization, specifically a comprehensive voltage regulation method for bipolar DC distribution networks based on multidimensional flexible interconnection equipment. Background Technology

[0002] With the continuous increase in the proportion of photovoltaic power generation and DC load equipment, the randomness and instability of new power sources have intensified, leading to power imbalances in the distribution network across different dimensions such as time and branches. These problems have caused issues such as inter-pole voltage imbalance and voltage exceeding limits, seriously affecting the safe operation of the bipolar DC distribution network.

[0003] Utilizing flexible interconnects to achieve controllable power transfer is an important approach for effectively managing various voltage issues. DC-DC converters based on dual active bridges can transfer power, balance load flow, and optimize system voltage distribution. However, traditional DC-DC interconnect devices can only transfer power between branches, lacking bipolar voltage balancing capabilities. Combining traditional dual active bridge interconnect devices with voltage balancers can effectively solve multi-objective control problems, but this traditional method involves two power conversion stages, reducing power conversion efficiency. Furthermore, this combination of diverse devices often increases the number of power electronic devices used and fails to fully utilize their flexibility, thus increasing control costs.

[0004] In terms of voltage regulation methods, existing methods typically optimize only a single objective, focusing solely on power imbalance or inter-pole voltage imbalance. However, a single regulation objective is insufficient to address the multiple voltage challenges currently faced by bipolar DC distribution networks. Developing voltage regulation methods that balance inter-pole voltage imbalance and voltage limit exceedance is a pressing issue that needs to be addressed. Summary of the Invention

[0005] The present invention addresses the shortcomings of the prior art by proposing a comprehensive voltage regulation method for bipolar DC distribution networks based on multidimensional flexible interconnection equipment. This method aims to effectively improve the voltage quality of bipolar DC distribution networks, thereby reducing operating losses and voltage imbalance.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: The present invention provides a comprehensive voltage regulation method for bipolar DC distribution networks based on multidimensional flexible interconnection equipment, characterized by the following steps: S1: Based on the characteristics and parameters of bipolar DC transformers, electric vehicles, and energy storage, construct bipolar DC transformer models, electric vehicle models, and energy storage models respectively, thereby forming a bipolar DC distribution network model; S2: Set the parameters of the multidimensional flexible interconnect device and establish the power transmission model of the multidimensional flexible interconnect device; S3: Based on the bipolar DC distribution network model, obtain renewable energy output data, DC load data, and multidimensional flexible interconnection equipment parameters within the bipolar DC distribution network, including photovoltaic data. S4: Based on the characteristics of bipolar DC distribution networks and multidimensional flexible interconnection equipment, establish a resource coordination control model for bipolar DC distribution networks based on multidimensional flexible interconnection equipment; S5: Based on the power transmission model of multi-dimensional flexible interconnection equipment and the resource coordination control model of bipolar DC distribution network, considering the optimal power flow distribution and voltage regulation of bipolar distribution network, a comprehensive voltage regulation optimization model based on multi-voltage level bipolar DC distribution network is established. S6: Based on the resource coordination control model of bipolar DC distribution network, the comprehensive voltage regulation optimization model of bipolar DC distribution network is transformed to establish and solve the linear relaxation model of comprehensive voltage regulation of bipolar DC distribution network, and output the comprehensive voltage regulation scheme of bipolar DC distribution network, including: control strategy and power transmission strategy of multi-dimensional flexible interconnection equipment, control strategy and power transmission strategy of bipolar DC transformer DCT, electric vehicle charging and discharging strategy, and energy storage equipment charging and discharging strategy.

[0007] The integrated voltage regulation method for bipolar DC distribution networks based on multidimensional flexible interconnection equipment described in this invention is characterized in that S2 includes the following steps: S2-1: Using equation (1) to obtain the relationship with the node Connected multidimensional flexible interconnected devices Extreme ports at Output power at time : (1) In equation (1), The polarity of the ports connected to multidimensional flexible interconnect devices, and ,when When, it indicates that the port is connected to the positive terminal and the neutral line. When, it indicates that the port is connected to the negative terminal and the neutral line. When, it indicates that the port is connected to the positive and negative terminals. Represents nodes Connected dual active bridges Extreme ports at The phase shift ratio between the primary and secondary bridges at time t; Represents nodes Connected dual active bridges Extreme ports at The equivalent voltage gain at time t is obtained from equation (2); Represents nodes Connected dual active bridges The actual turns ratio at the pole ports; Represents nodes Connected dual active bridges The switching frequency of the polar port; To represent nodes Connected dual active bridges The equivalent inductance value of the terminal; (2) S2-2: When Using equation (3), we can obtain the relationship with the node. Connected multidimensional flexible interconnected devices Extreme ports at Maximum output power at any time : (3) Using equation (4), we obtain the relationship with the node. Connected multidimensional flexible interconnected devices Extreme ports at Minimum output power at time : (4) S2-3: Using equation (5) to obtain the node and nodes Multidimensional flexible interconnected devices connected between them Losses generated during continuous operation : (5) In equation (5), This indicates the operating efficiency of multidimensional flexible interconnected devices. Represents nodes Connected multidimensional flexible interconnected devices Extreme ports at Port power at any given time; Represents nodes Connected multidimensional flexible interconnected devices Extreme ports at Port power at any given time; S2-4: Constructing power transmission constraints on both sides of a multidimensional flexible interconnect device using equations (6) and (7): (6) (7) In equations (6) and (7), Represents nodes and nodes Multidimensional flexible interconnected devices Extreme ports at Minimum output power at time , Represents nodes and nodes Multidimensional flexible interconnected devices Extreme ports at Output power at any moment Represents nodes and nodes Multidimensional flexible interconnected devices Extreme ports at Maximum output power at any given time.

[0008] Furthermore, S5 includes the following steps: S5-1: Objective function for constructing an integrated voltage regulation optimization model for a bipolar DC distribution network based on multiple voltage levels. : (8) In equation (8), Losses incurred during the operation of bipolar DC distribution networks; The losses incurred during the operation of all equipment; This represents the penalty cost incurred by a bipolar DC distribution network due to voltage exceeding limits; and we have: (9) In equation (9), and These are the unit operating loss cost of the bipolar DC distribution network and the unit load failure cost caused by voltage overruns, respectively. , Indicates the positive electrode. Indicates the centerline. Indicates the negative electrode; It is the total duration; It is a collection of branches in a bipolar DC distribution network; Represents a node Where Extreme The penalty cost resulting from exceeding the voltage limit at any given time. Represents a node Where Extreme The active power consumed by the load at any given moment; Represents a node Where Extreme The balance coefficient at any given time; Indicating multidimensional flexible interconnected devices The losses incurred during continuous operation; The nodes are obtained using equation (10). Where Extreme Voltage over-limit penalty coefficient at time : (10) In equation (10), The minimum voltage required for safe operation of a bipolar DC distribution network. This represents the minimum voltage desired for optimization. Indicates the desired maximum voltage. This indicates the maximum voltage at which a bipolar DC distribution network can operate safely.

[0009] The present invention provides an electronic device, including a memory and a processor, characterized in that the memory is used to store a program that supports the processor in executing the comprehensive voltage regulation method for bipolar DC distribution networks based on multidimensional flexible interconnection devices, and the processor is configured to execute the program stored in the memory.

[0010] The present invention discloses a computer-readable storage medium storing a computer program, characterized in that the computer program, when executed by a processor, performs the steps of the comprehensive voltage regulation method for bipolar DC distribution networks based on multidimensional flexible interconnection devices.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention takes solving various voltage problems such as inter-pole voltage imbalance and voltage limit exceedance in bipolar DC distribution networks as a comprehensive optimization goal, and proposes a comprehensive voltage regulation method based on multi-dimensional flexible interconnection equipment. This method overcomes the shortcomings of existing regulation methods that only optimize a single goal and cannot simultaneously solve problems such as inter-pole voltage imbalance and voltage limit exceedance. This makes voltage regulation more comprehensive and effective, and has good adaptability to bipolar DC distribution networks with a high proportion of distributed power sources.

[0012] 2. This invention incorporates multidimensional flexible interconnection devices into voltage regulation considerations, overcoming the shortcomings of existing technologies that only use a combination of traditional dual active bridge interconnection devices and voltage balancers. It eliminates the need for additional voltage balancers, effectively reducing equipment costs and system complexity, while improving regulation efficiency and equipment utilization.

[0013] 3. Based on the topology of bipolar DC distribution networks, this invention utilizes the multi-port power regulation function of multi-dimensional flexible interconnection equipment and model transformation methods to overcome the problems of complex power flow calculation and high solution difficulty in bipolar DC distribution networks. By using linearization and convex relaxation techniques, the complexity of the model is effectively reduced, and the efficiency and accuracy of model solution are improved. Moreover, it demonstrates good economic efficiency and applicability in distribution networks of different scales and in scenarios with a high proportion of distributed renewable energy access. Attached Figure Description

[0014] Figure 1a This is a diagram of an asymmetric bipolar dual active bridge topology; Figure 1b This is a schematic diagram of a multidimensional flexible interconnected device structure; Figure 2 This is a graph showing renewable energy output data from photovoltaics and DC load data; Figure 3a This is a schematic diagram illustrating the operation of a multidimensional flexible interconnected device; Figure 3b This is a schematic diagram of the charging and discharging method for energy storage; Figure 3c This is a schematic diagram of the mode switching method for DCT-1; Figure 4 This is a schematic diagram of the voltage index of the distribution network under the proposed method; Figure 5 This is a topology diagram of a bipolar DC distribution network with two voltage levels; Figure 6 This is a flowchart of a comprehensive voltage regulation method for bipolar DC distribution networks based on multidimensional flexible interconnection devices. Detailed Implementation

[0015] In this embodiment, a comprehensive voltage regulation method for a bipolar DC distribution network based on multidimensional flexible interconnection equipment is described, such as... Figure 1a and Figure 1b As shown, comprehensive control over issues such as inter-electrode voltage imbalance and voltage limit exceedance is achieved by coordinating multi-dimensional flexible interconnected devices, energy storage devices, and mode-switchable DCTs. Specifically, as... Figure 6 As shown, the method includes the following steps: S1: Based on the characteristics and parameters of bipolar DC transformers, electric vehicles, and energy storage, construct bipolar DC transformer models, electric vehicle models, and energy storage models respectively, thereby forming a bipolar DC distribution network model.

[0016] S1-1: A bipolar DC controller can be equivalent to two separately controlled DCT modules, then the... The relationship between the output power of the positive DCT module and the voltage on both sides is shown in equations (1) and (2): (1) (2) In equations (1) and (2), Connect the polarities of different ports to the transformer, and ,when When, it indicates that the port is connected to the positive terminal and the neutral line. When, it indicates that the port is connected to the negative terminal and the neutral line. When, it indicates that the port is connected to the positive and negative terminals; For high frequency isolation transformer Turns ratio at any given time; Bipolar DC transformer Extreme ports at The shift ratio within half a switching cycle at any given moment; The switching frequency of the DCT; This is the equivalent inductance value of the DCT; For nodes Connected DCT Extreme ports at The connection port voltage at any given time, For nodes Connected DCT Extreme ports at The voltage at the connection port at any given time; For nodes Connected DCT Extreme ports at Output power at any moment For nodes Connected DCT Extreme ports at Output power at any given moment.

[0017] The bipolar DCT consists of two unipolar DC transformer modules, which achieve fine power regulation through independent control. Each module can independently adjust its shift ratio, thereby outputting different power.

[0018] Equation (1) involves the multiplication of multiple variables. To facilitate linearization, this paper simplifies it to obtain equation (3). This simplification is based on the following assumptions: In the non-constant ratio mode, the deviation between the actual voltage ratio and the rated voltage ratio is within a reasonable range, therefore : (3) In equation (3), It is with nodes Connected DCT Extreme ports at The actual voltage ratio on both sides at a given time; It is with nodes Connected DCT The deviation coefficient caused by the inconsistency between the actual voltage ratio at the pole port and the turns ratio of the high-frequency isolation transformer is relevant in constant ratio control. ; DCT Extreme ports at Compared to the equivalent shift at time, .

[0019] To ensure that the DCT can adapt to various needs, the DCT is usually set to a constant ratio mode, which adapts to various power flow demands by controlling the power on both sides. However, since the voltage at the end of the low-voltage side of the distribution network is often too low, the constant ratio mode on the low-voltage side can effectively alleviate this situation, but it will increase the system's operating losses. Therefore, switching the control mode of the DCT is an effective method to balance the voltage level and the system's operating losses. To ensure that the DCT can only adopt one control mode at the same time, the DC transformer must meet the constraint shown in equation (4): (4) In equation (4), This represents the total number of time periods in the model; The matrix represents the control mode. ; Indicates the time period Do you want to choose the first one? There are several control modes, where a value of 1 indicates that the first mode is selected. There are several control modes, with a value of 0 indicating that no mode is selected.

[0020] S1-2: The energy storage system uses Equations (5)-(9) to coordinate the control of energy storage devices on the high-voltage and low-voltage sides for charging and discharging, balancing the instability of the distribution network load and the instability of renewable energy output. This helps to suppress voltage fluctuations and optimize power distribution, and is a core component for improving energy efficiency, reducing losses and voltage imbalance.

[0021] (5) (6) (7) (8) (9) In equations (5)-(9), For nodes The maximum charging power of the connected energy storage device. For nodes The maximum discharge power of the connected energy storage device; For nodes Connected energy storage devices Auxiliary variables set at all times, when the energy storage device is charging, cause... =1, during discharge, let =0; For nodes Minimum state of charge of connected energy storage For nodes The maximum value of the energy storage state of charge. For nodes Initial value of the connected energy storage state of charge; For nodes Connected energy storage devices Time capacity; For nodes Connected energy storage devices Always connected The equivalent load of the pole; To and The auxiliary variables set for the corresponding level connection are connected to... The value is 1 when the pole is active and 0 when not connected. It is a set of system nodes; This indicates a node with energy storage equipment. .

[0022] S2: Set the parameters of the multidimensional flexible interconnect device and establish the power transmission model of the multidimensional flexible interconnect device; S2-1: The device allows bidirectional power flow between four ports, with each port controlled independently. Compared to solutions that combine voltage balancers with DC-DC devices for interconnection, the proposed device has a more compact structure and a simpler control method. The device possesses cross-branch power transmission capabilities, supporting interconnection and flexible power flow control between different ports. While achieving inter-pole power balancing, it further enhances the coordination capabilities between branches. The device can achieve dynamic power regulation between positive and negative poles, extending beyond existing single-pole branch power controllable transmission technology to inter-pole coupling control, effectively addressing unbalanced load sources between poles. The coordinated regulation of power transfer between branches and power between poles together constitutes the multi-dimensional power regulation capability of this device, providing flexible power flow management capabilities and comprehensive voltage optimization methods for bipolar DC distribution networks.

[0023] S2-2: Based on the relationship between the secondary current and parameters such as inductance and transformer turns ratio under different operating conditions of two sets of asymmetrical bipolar active bridges, the input power of the positive / negative poles is derived using equation (10): (10) In equation (10), To connect different port polarities for multidimensional flexible interconnect devices; Represents nodes Connected multidimensional flexible interconnected devices Extreme ports at Output power at any given moment; Represents nodes Connected asymmetric dual active bridges Extreme ports at The phase shift ratio between the primary and secondary bridges at time t; Represents nodes Connected asymmetric dual active bridges Extreme ports at The equivalent voltage gain at time t is given by equation (11); Represents nodes Connected dual active bridges The actual turns ratio at the pole ports; Represents nodes Connected dual active bridges The switching frequency of the polar port; To represent nodes Connected dual active bridges The equivalent inductance value of the terminal; and we have: (11) From equation (10), it can be seen that when At this time, the output power of the device reaches its maximum, as shown in equation (12).

[0024] (12) In equation (12), Represents nodes Connected multidimensional flexible interconnected devices Extreme ports at Maximum output power at any given time.

[0025] To satisfy the ZVS-on constraints of all switches, and There are certain constraints between them, which leads to a lower limit on the transmission power of the device, as shown in equation (13): (13) In equation (13), Represents nodes Connected multidimensional flexible interconnected devices Extreme ports at Minimum output power at any given time; S2-3: Using equation (14) to obtain the node and nodes Multidimensional flexible interconnected devices connected between them Losses generated during continuous operation : (14) In equation (14), This indicates the efficiency of the operation of multidimensional flexible interconnected devices. Represents nodes Connected multidimensional flexible interconnected devices Extreme ports at Port power at any given time; Represents nodes Connected multidimensional flexible interconnected devices Extreme ports at Port power at any given time.

[0026] S2-4: Power transmission constraints on both sides of a multidimensional flexible interconnect device are constructed using equations (15) and (16): (15) (16) In equations (15) and (16), Represents nodes and nodes Multidimensional flexible interconnected devices Extreme ports at Minimum output power at time , Represents nodes and nodes Multidimensional flexible interconnected devices Extreme ports at Output power at any moment Represents nodes and nodes Multidimensional flexible interconnected devices Extreme ports at Maximum output power at any given time.

[0027] S3: Based on the bipolar DC distribution network model, obtain renewable energy output data, DC load data, and multidimensional flexible interconnection equipment parameters within the bipolar DC distribution network, including photovoltaic data. S3-1: Renewable energy output data and DC load data of photovoltaic power generation are as follows: Figure 2 As shown; S3-2: Multidimensional Flexible Interconnection Device Frequency 40 kHz, inductor It is 62.5 μH.

[0028] S4: Based on the characteristics of bipolar DC distribution networks and multidimensional flexible interconnection equipment, establish a resource coordination control model for bipolar DC distribution networks based on multidimensional flexible interconnection equipment; S4-1: A bipolar DC distribution network consists of three conductors: + represents the positive line, o represents the neutral line, and – represents the negative line. Any two nodes on different conductors can form a source-load access port (i.e., + ~ o, - ~ o, and + ~ -), which are represented by p, n, and b respectively. Indicates port polarity. ; Indicates the polarity of the pole. Using equation (17), we obtain the representations of the nodes respectively. The power type is hour Positive decoupling coefficient at time 1 ,node The power type is hour Midline decoupling coefficient at time 1 ,node The power type is hour Negative decoupling coefficient at time 1 : (17) In equation (17), For nodes Place The coefficient by which the load power at time p is converted to the node-to-ground load. For nodes Place The coefficient by which the load power at time b is converted to the node-to-ground load. For nodes Place The coefficient by which the load power of pole n is converted to the node-to-ground load at time n; Represents a node The power type is hour Moment p Extreme power, Represents a node The power type is hour Moment n Extreme power, Represents a node The power type is hour Moment b Extreme power, Indicates the power type, including load, power source, and energy storage power.

[0029] Inter-electrode load conversion factor for different voltage levels It is determined by the voltage at the inter-electrode node, as shown in equation (18): (18) In equation (18), Represented as nodes Place The positive line voltage at time t, where Represented as nodes Place The negative line voltage at time [time]. Represented as nodes Place The neutral line voltage at time t.

[0030] S5: Based on the power transmission model of multi-dimensional flexible interconnection equipment and the resource coordination control model of bipolar DC distribution network, considering the optimal power flow distribution and voltage regulation of bipolar distribution network, a comprehensive voltage regulation optimization model based on multi-voltage level bipolar DC distribution network is established. S5-1: In order to solve the problems of voltage imbalance and voltage over-limit at the same time, this invention integrates the control objectives of different types of voltage problems into a unified collaborative optimization model, and constructs a comprehensive voltage control optimization model for multi-voltage level bipolar DC distribution networks. The objective function of the integrated voltage regulation optimization model for a bipolar DC distribution network based on multiple voltage levels is constructed using equation (19). : (19) In equation (19), The losses incurred during system operation; The losses incurred during equipment operation; This represents the penalty cost incurred by the system due to voltage exceeding the limit; and we have: (20) In equation (20), and These are the unit operating loss cost of the system and the unit load failure cost caused by voltage exceeding limits, respectively. , Indicates the positive electrode. Indicates the centerline. Indicates the negative electrode; It is the total duration; It is a collection of branches in a bipolar DC distribution network; Represents a node Where Extreme The penalty cost resulting from exceeding the voltage limit at any given time. Represents a node Where Extreme The active power consumed by the load at any given moment; Represents a node Where Extreme The balance coefficient at any given time; Indicating multidimensional flexible interconnected devices The losses incurred during continuous operation; The nodes are obtained using equation (21). Where Extreme Voltage over-limit penalty coefficient at time : (twenty one) In equation (21), The minimum voltage required for safe operation of a bipolar DC distribution network. This represents the minimum voltage desired for optimization. Indicates the desired maximum voltage. This indicates the maximum voltage at which a bipolar DC distribution network can operate safely.

[0031] S5-2: After decoupling, the three conductors of the bipolar DC distribution network operate independently, namely the positive pole, the neutral line, and the negative pole. The power between the poles is no longer coupled with the node voltage and the line current. The three conductors need to follow the system power flow constraints shown in Equations (22) to (25): (twenty two) (twenty three) (twenty four) (25) In equations (22)-(25), This is the set of nodes connected to the system and the DCT. Indicates the different polarities of the nodes; for Timetable superior Active power transmitted in the direction of the slave node. Flow direction ; line superior The resistance of the pole; for Time Node of Active power is injected into the pole; for Time Node of Polar voltage; for Timetable superior The current transmitted through the pole is directed from the node. Flow to Node ; for Time-based DCT and nodes Connect one side The output power of the pole; for Time Node Photovoltaic The maximum output of active power; for Multi-dimensional flexible interconnected devices to nodes of Active power injected into the pole; for Energy storage from nodes The active power of charging. for Electric vehicles from the node of Active power of the electrode charging; for Time Node Place The active power consumed by extreme loads.

[0032] In addition to the network constraints mentioned above, the power flow calculation model also needs to satisfy system operation safety constraints. System safety constraints are mainly divided into basic safety constraints and bipolar unbalanced voltage constraints, and their constraint models are shown below: The basic security constraints of the distribution network are constructed using equations (26) and (27): (26) (27) In equations (26) and (27), for Time reference node The voltage of the pole, and They are respectively time The upper and lower limits of the voltage level at which the corresponding node of the polar system is located; and They are respectively Different voltage level lines in the time system Upper and lower limits of electrode current.

[0033] Construct inter-electrode unbalanced voltage constraints using equation (28): (28) In equation (28), Voltage level Time node The positive voltage, Voltage level Time node The negative voltage.

[0034] S6: The established integrated voltage regulation model based on multi-dimensional flexible interconnection equipment is a mixed-integer nonlinear model, which is difficult to solve directly using existing methods. Based on the multi-voltage-level bipolar DC distribution network integrated voltage regulation optimization model established in step S4, various linearization and relaxation methods are used to linearize and relax the power flow calculation model, objective function, constraints, and equipment used in the regulation method. This transforms the bipolar DC distribution network integrated voltage regulation model into a mixed-integer second-order cone model, thereby establishing a linearized and relaxed model of the bipolar DC distribution network integrated voltage regulation model. This enables fast and accurate solution. By solving this model, the integrated voltage regulation scheme of the bipolar DC distribution network is output, as shown in Figure 3.

[0035] To enable those skilled in the art to better understand the present invention, the numerical example analysis includes the following components: I. Example Description and Simulation Result Analysis: To verify its effectiveness, this invention used, for example... Figure 5 A case study analysis is conducted on a two-voltage-level bipolar DC distribution network. The reference voltage on the high-voltage side is ±10 kV, and the reference voltage on the low-voltage side is ±375 V. This case study includes six photovoltaic arrays, two DC charging stations, two sets of energy storage, two sets of DCT devices, and one set of multidimensional flexible interconnection devices. During the testing and analysis, the two sets of DCT devices are connected between nodes 6 and 26 and nodes 15 and 16, respectively. The DCT device frequency is 40 kHz, and the inductance is 2.5 mH. The multidimensional flexible interconnection device is installed between nodes 22 and 12, with a device frequency of 40 kHz and an inductance of 62.5 μH.

[0036] In this example, to better verify the advantages of the proposed equipment and integrated voltage regulation method compared to other regulation schemes, three schemes were compared: Case 1, which does not employ a voltage balance regulation method; Case 2, which uses traditional regulation equipment (energy storage equipment, power flow controller) for voltage regulation; and Case 3, which utilizes the integrated voltage regulation method proposed in this paper. The optimization results of the three methods after running are shown in Table 1.

[0037] Table 1 As shown in Table 1, the system losses in Case 3 were reduced by 51.75% compared to Case 1 and by 22.44% compared to Case 2, demonstrating a significant improvement in system operating efficiency. Case 3, by integrating multi-dimensional flexible interconnected devices, distributed energy storage collaboration, and the variable control mode of DCT, constitutes a comprehensive voltage regulation method, achieving a comprehensive breakthrough in system energy efficiency, voltage safety, and balance. Figure 4 As shown, its system has the lowest operating loss, saving 51.75% of energy compared to Case 1; the voltage over-limit rate is close to zero, ensuring the safety of power supply; and the voltage imbalance is the lowest, supporting the long-term stable operation of the system. Finally, under the conditions of high photovoltaic penetration and large-scale distribution networks, the method has been verified to demonstrate good economic efficiency and applicability in distribution networks of different sizes and high proportion of distributed renewable energy access scenarios.

Claims

1. A method for comprehensive voltage regulation of bipolar DC power distribution network based on multi-dimensional flexible interconnection equipment, characterized in that, The method comprises the following steps: S1: According to the characteristics and parameters of bipolar DC transformer, electric vehicle and energy storage, a bipolar DC transformer model, an electric vehicle model and an energy storage model are respectively constructed to form a bipolar DC distribution network model; S2: Parameters of the multi-dimensional flexible interconnection device are set, and a power transmission model of the multi-dimensional flexible interconnection device is established; S3: According to the bipolar DC distribution network model, renewable energy output data and DC load data of the bipolar DC distribution network including photovoltaic and multi-dimensional flexible interconnection device parameter data are obtained; S4: According to the characteristics of the bipolar DC distribution network and the characteristics of the multi-dimensional flexible interconnection device, a bipolar DC distribution network resource coordination control model based on the multi-dimensional flexible interconnection device is established; S5: Based on the power transmission model of the multi-dimensional flexible interconnection device and the bipolar DC distribution network resource coordination control model, considering bipolar optimal power flow distribution and voltage regulation, a comprehensive voltage regulation optimization model of the bipolar DC distribution network based on multi-voltage levels is established; S6: Based on the bipolar DC distribution network resource coordination control model, the comprehensive voltage regulation optimization model of the bipolar DC distribution network is transformed to establish a linear relaxation model of the bipolar DC distribution network comprehensive voltage regulation and solve it, and output the comprehensive voltage regulation scheme of the bipolar DC distribution network, including: the control strategy and power transmission strategy of the multi-dimensional flexible interconnection device, the control strategy and power transmission strategy of the bipolar DC transformer DCT, the strategy of electric vehicle charging and discharging, and the strategy of energy storage device charging and discharging. 2.The comprehensive voltage regulation method of a bipolar DC distribution network based on a multi-dimensional flexible interconnection device according to claim 1, characterized in that, S2 comprises the following steps: S2-1: Obtain the output power of the multi-dimensional flexible interconnection device connected with the node at the moment of time t using formula (1) :​​ (1) In formula (1), is the port polarity connected by the multi-dimensional flexible interconnection device, and when , it indicates that the port connects the positive pole and the neutral line, when , it indicates that the port connects the negative pole and the neutral line, when , it indicates that the port connects the positive pole and the negative pole, indicates the extreme port of the dual active bridge connected with the node the phase shift ratio between the primary bridge and the secondary bridge at the moment ; indicates the extreme port of the dual active bridge connected with the node the equivalent voltage gain at the moment , which is obtained from formula (2); indicates the actual transformation ratio of the extreme port of the dual active bridge connected with the node ; indicates the switching frequency of the extreme port of the dual active bridge connected with the node ; is the equivalent inductance value of the extreme port of the dual active bridge connected with the node ; (2) S2-2: When Using equation (3), we can obtain the relationship with the node. Connected multidimensional flexible interconnected devices Extreme ports at Maximum output power at any time : (3) The node is connected to a multi-dimensional flexible interconnect device using formula (4) The minimum output power of the port at time :​ (4) S2-3: Obtain the multi-dimensional flexible interconnect device connected between node and node at time moment running loss : (5) In formula (5), representing the operating efficiency of the multi-dimensional flexible interconnection device, representing the port power of the extreme port of the multi-dimensional flexible interconnection device connected with the node at the moment t; representing the port power of the extreme port of the multi-dimensional flexible interconnection device connected with the node at the moment t; representing the port power of the extreme port of the multi-dimensional flexible interconnection device connected with the node at the moment t; representing the port power of the extreme port of the multi-dimensional flexible interconnection device connected with the node at the moment t; S2-4: The power transmission constraints of the two sides of the multi-dimensional flexible interconnection device are constructed by using formula (6) and formula (7): (6) (7) in formula (6) and formula (7), denotes the minimum output power of the multi-dimensional flexible interconnect device connected between the nodes and the node at the time instant , denotes the output power of the multi-dimensional flexible interconnect device connected between the nodes and the node at the time instant , denotes the maximum output power of the multi-dimensional flexible interconnect device connected between the nodes and the node at the time instant , denotes the maximum output power of the multi-dimensional flexible interconnect device connected between the nodes and the node at the time instant .

3. The method of claim 2, wherein the method further comprises: S5 comprises the following steps: S5-1: Constructing an objective function of a comprehensive voltage regulation optimization model of a bipolar direct current power distribution network based on multiple voltage levels : (8) In formula (8), is the loss generated by the operation of the bipolar DC distribution network; is the loss generated by the operation of all devices; represents the penalty cost of the bipolar DC distribution network due to voltage out-of-limit; and has: (9) In equation (9), and These are the unit operating loss cost of the bipolar DC distribution network and the unit load failure cost caused by voltage exceeding limits, respectively. , Indicates the positive electrode. Indicates the centerline. Indicates the negative electrode; It is the total duration; It is a collection of branches in a bipolar DC distribution network; Represents a node Where Extreme The penalty cost resulting from exceeding the voltage limit at any given time. Represents a node Where Extreme The active power consumed by the load at any given moment; Represents a node Where Extreme The balance coefficient at any given time; Indicating multidimensional flexible interconnected devices The losses incurred during continuous operation; The node is obtained using formula (10) wherein the pole at the moment of voltage overrun penalty coefficient : (10) In formula (10), denotes the minimum voltage for safe operation of the bipolar DC distribution grid, denotes the minimum voltage for optimized expectation, denotes the maximum voltage for optimized expectation, denotes the maximum voltage for safe operation of the bipolar DC distribution grid.

4. An electronic device comprising a memory and a processor, characterized in that The memory is used to store a program supporting the processor to execute the bipolar DC distribution network comprehensive voltage regulation method based on the multi-dimensional flexible interconnection device according to any one of claims 1-3, and the processor is configured to execute the program stored in the memory.

5. A computer-readable storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to perform the steps of the bipolar DC distribution network comprehensive voltage regulation method based on the multi-dimensional flexible interconnection device according to any one of claims 1-3.

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