A method for calculating the transmission power limit of a soft switching device in a direct current microgrid group

Abstract

The application discloses a transmission power limit calculation method of a DC soft switching device in a DC microgrid group, and aims at solving the problem that the transmission power limit of a DC-SOP in a DC microgrid group is difficult to accurately quantify due to double constraints of control and capacity, and comprises the following steps: firstly, a DC microgrid containing multiple distributed power sources and constant power units is equivalently aggregated into a port droop model; then, the model is combined with DAB transmission power, and the operating range of a DC microgrid bus voltage and the DAB phase shift limit are considered, and the analytical expressions of the forward and reverse power transmission of the DC-SOP are respectively given, and the asymmetry of the bidirectional transmission power limit caused by the droop control is disclosed. The application provides a clear power boundary for the planning and operation of a DC-SOP interconnected microgrid system, and is helpful to improving the safety and economy of the system operation.

Description

Technical Field

[0001] This invention relates to the field of flexible interconnection and operation control technology of DC microgrid clusters, specifically to a method for calculating the transmission power limit of soft switching devices in DC microgrid clusters. Background Technology

[0002] DC microgrids, by integrating distributed power sources, energy storage devices, and loads, can effectively improve the absorption capacity of new energy sources and enhance power supply reliability. With the increasing penetration rate of distributed energy, single microgrids, due to their limited capacity and weak disturbance immunity, cannot fully meet the needs of high-proportion renewable energy access and diverse user electricity demands. Therefore, connecting multiple geographically adjacent DC microgrids into a microgrid cluster using flexible interconnection devices can achieve energy sharing and power support between subgrids, improving system reliability, flexibility, and economy.

[0003] In the flexible interconnection scheme, two dual active bridge (DAB) converters are connected back-to-back to form a direct current soft open point (DC-SOP). One DAB in this device uses constant voltage control to maintain a constant common bus voltage, while the other DAB uses constant power control to achieve power transfer between microgrids. The advantages of DC-SOP compared to a single DAB are: it can achieve fault isolation between microgrids; it has a modular structure, is easily expandable to multiple ports, has strong networking capabilities, and is suitable for multi-microgrid group networking; it supports plug-and-play microgrids, and the original system structure does not need to be changed when a new microgrid is connected.

[0004] Distributed power sources within a DC microgrid typically employ droop control, where the bus voltage and output power are linearly related. Droop control enables power distribution among distributed power sources without communication, offering good reliability and plug-and-play characteristics. During the microgrid planning phase, the droop factor is selected considering the microgrid's maximum transmission power and voltage operating range. However, when microgrids are interconnected via DC-SOPs, the transmission power limit is not only constrained by the microgrid's internal control but also by DAB capacity limitations and the coupling effects of parameters from adjacent microgrids.

[0005] In summary, for DC-SOP interconnected microgrid systems, existing technologies lack a calculation method that can simultaneously consider converter capacity constraints, microgrid equivalent droop characteristics, and voltage operating range, and can provide analytical expressions for the forward and reverse transmission power limits respectively. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by proposing a method for calculating the transmission power limit of soft-switching devices in DC-SOP clusters. The aim is to accurately obtain analytical expressions for the limits of forward and reverse transmission power in DC-SOP, revealing the asymmetry in bidirectional transmission power limits caused by droop control. This provides a clear power safety boundary for the planning and operation of DC-SOP interconnected microgrid systems, contributing to improved system safety and economy.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: The present invention provides a method for calculating the transmission power limit of a soft-switching device in a DC microgrid group, characterized by the following steps: Step 1: Establish a DC soft-switching device DC-SOP consisting of a first dual active bridge converter DAB1 and a second dual active bridge converter DAB2 connected back-to-back. DAB1 is connected to the first DC microgrid and uses constant voltage control to maintain a constant common DC bus voltage. DAB2 is connected to the second DC microgrid and uses constant power control to achieve power transmission. Step 2: Taking the output power direction of any DC microgrid as positive, perform internal aggregation on each DC microgrid to establish its port equivalent droop control model; Step 3: Based on the relationship between the transmission power of DAB1 and DAB2 and the voltage and displacement ratio at both ends, and considering the voltage operating range of the DC microgrid bus and the capacity constraints of the dual active bridge converter, a limit expression for the transmission power of DC-SOP is constructed based on the port equivalent droop model of the DC microgrid on both sides, under the conditions of forward transmission power and reverse transmission power.

[0008] The characteristic of the method for calculating the transmission power limit of a soft-switching device in a DC microgrid group described in this invention is that, in step 2, the equivalent droop control model of the port of any side of the DC microgrid is constructed using equation (2): (2) In formula (2): V The bus voltage of either side of the DC microgrid; V 0,eq The equivalent rated voltage of the DC bus on either side of the DC microgrid; m eq The equivalent droop coefficient of the DC microgrid on either side; P out The power output from either side of the DC microgrid to the DC-SOP; P N This represents the total output power of all constant power units in any DC microgrid on either side.

[0009] Furthermore, step 3 includes: When the power of DC-SOP P DC-SOP During forward transmission, the first DC microgrid outputs power through DAB1, and the second DC microgrid absorbs power through DAB2. The forward transmission power limit of DAB1 is determined using equations (13) and (19), respectively. P + 1,max and the forward transfer power limit of DAB2 P + 2,max Thus, the forward transfer power limit of DC-SOP is obtained. : (13) (19) In equations (2) and (3), K 1= n 1 / f s1 L 1, K 2= n 2 / f s2 L 2 represents constants related to the parameters of DAB1 and DAB2, respectively; f s1 , f s2 These are the switching frequencies of DAB1 and DAB2, respectively. n 1, n 2 represents the turns ratio of the primary and secondary sides of transformers DAB1 and DAB2, respectively; L 1, L 2 represents the sum of the transformer leakage inductance and the external inductance of DAB1 and DAB2, respectively; V dc The voltage of the common DC bus; V 1,0 This is the equivalent rated voltage of the DC bus of the first DC microgrid; V 2,0 This is the equivalent rated voltage of the DC bus of the second DC microgrid; V 1,min This is the lower limit of the allowable bus voltage for the first DC microgrid; V 2,max This is the upper limit of the allowable bus voltage for the second DC microgrid; P 1,N This represents the total output power of all constant power units in the first DC microgrid. P 2,N This represents the total output power of all constant power units in the second DC microgrid. m 1 represents the equivalent droop coefficient of the first DC microgrid;m 2 represents the equivalent droop coefficient of the second DC microgrid; When the power of DC-SOP P DC-SOP During reverse transmission, the first DC microgrid absorbs power through DAB1, and the second DC microgrid outputs power through DAB2. Equations (23) and (29) are used to determine the absolute value of the reverse transmission power limit of DAB1, respectively. P - 1,max |Absolute value of the reverse transfer power limit of DAB2| P - 2,max | Thus, the absolute value of the reverse transfer power limit of DC-SOP is obtained. : (twenty three) (29) In equations (23) and (29): V 1,max This is the upper limit of the allowable bus voltage for the first DC microgrid; V 2,min This is the lower limit of the allowable bus voltage for the second DC microgrid.

[0010] The present invention provides an electronic device, including a memory and a processor, characterized in that the memory is used to store a program supporting the processor in performing the method described therein, and the processor is configured to execute the program stored in the memory.

[0011] The present invention discloses a computer-readable storage medium storing a computer program, characterized in that the computer program is executed by a processor to perform the steps of the method described thereon.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention equates a DC microgrid, which includes multiple droop-controlled distributed power sources and multiple constant power units, to a droop-controlled model, thereby obtaining a method and expression for calculating the DC-SOP transmission power limit of the internal control and DAB capacity of the DC microgrid, providing a clear power boundary for the safe operation of the system.

[0013] 2. This invention establishes a port equivalent droop control model, which aggregates multiple distributed power sources and constant power units within a microgrid into three parameters: equivalent droop coefficient, equivalent rated voltage, and total output power of the constant power unit. This preserves the external characteristics of port voltage changing with power, while reducing the complexity and parameter dimensionality of extreme calculations.

[0014] 3. This invention improves computational efficiency by uniformly mapping the DAB shift ratio constraint and the microgrid voltage operating range constraint to the transmission power variable, and by utilizing the monotonicity of the transmission power function to obtain an explicit analytical expression for the transmission power limit.

[0015] 4. By deriving the forward and reverse transmission power limit expressions respectively, this invention can reflect the asymmetry of the microgrid's output and absorption power under the upper and lower voltage limits, thereby improving the accuracy and operational safety of bidirectional power dispatch commands. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the DAB structure. Figure 2 This is a schematic diagram of the DC-SOP structure. Figure 3 Diagram of a single DC microgrid structure; Figure 4 This is a diagram showing the interconnection of two DC microgrids in a DC-SOP configuration. Figure 5 This diagram illustrates the widespread application of multiple DAB parallel microgrids. Detailed Implementation

[0017] In this embodiment, due to the interaction between voltage-power coupling caused by droop control within the microgrid, bus voltage operating range limitations, and DAB capacity limitations, a method for calculating the transmission power limit of a Direct Current SoftOpen Point (DC-SOP) in a DC microgrid cluster is proposed. This method can accurately obtain the analytical expressions for the forward and reverse transmission power limits of the DC-SOP, thereby providing an accurate power safety boundary for the system. Specifically, the method includes the following steps: Step 1. Construct a DC-SOP structure consisting of DAB1 and DAB2 connected back-to-back. The structure of the DAB is as follows: Figure 1 As shown, the DC-SOP structure is as follows: Figure 2 As shown. DAB1 employs constant voltage control to maintain the common DC bus voltage. V dc DAB2 uses constant power control to achieve power transmission; DAB1 is the first DC microgrid, and DAB2 is connected to the second DC microgrid. The positive direction of power transmission in DC-SOP is defined as from left to right.

[0018] Equation (1) gives the ideal transmission power of DAB1. Ideal transmission power of DAB2 : (1) In equation (1), K 1=n 1 / f s1 L 1; K 2= n 2 / f s2 L 2; f s1 , f s2 These are the switching frequencies of DAB1 and DAB2, respectively. L 1, L 2 represents the sum of the transformer leakage inductance and the external inductance of DAB1 and DAB2; n 1, n 2 represents the turns ratio of the primary and secondary sides of transformers DAB1 and DAB2; D 1, D 2 is the shift comparison between DAB1 and DAB2; V dc The voltage of the common DC bus; V 1 represents the port voltage of the DC-SOP connected to the first DC microgrid; V 2 represents the port voltage of the DC-SOP connected to the second DC microgrid.

[0019] Step 2. Perform internal aggregation on each side of the droop control DC microgrid to establish its port equivalent droop control model: Step 2.1 Internal structure diagram of a single DC microgrid is shown below. Figure 3 As shown, the output power of the microgrid is defined as positive. The internal composition of the microgrid is as follows: (1) M (2) Distributed generation (DG) systems using droop control are connected in parallel on the same bus. N The number of constant power units (including unschedulable sources and loads), the first j Output power of each unit P j It can be positive or negative.

[0020] Construct the first using equation (2) i The droop control equation for each DG: (2) In equation (2), V This is the common bus voltage; V i0 For the first i The rated voltage of the busbar of each DG; m i It is the first i The droop coefficient of each DG; P i It is the first i The output power of each DG (constantly positive).

[0021] Step 2.2 Perform internal aggregation on a single microgrid: The internal power balance equation of the microgrid is constructed using equation (3): (3) In equation (3), P out This represents the total output power of the microgrid.

[0022] Arranging equations (2) and (3) yields equation (4): (4) According to equation (4), the equivalent droop coefficient of the microgrid can be defined using equation (5). : (5) According to equation (4), the equivalent bus rated voltage of the microgrid can be defined using equation (6). : (6) Define the total output power of unschedulable sources and constant power loads within a microgrid. Total output power of distributed generation (DG) within the microgrid .

[0023] Then, using equation (7), an equivalent model of the microgrid port can be constructed: (7) Step 3. The structure of interconnecting two DC microgrids using DC-SOP is as follows: Figure 4 As shown, based on the relationship between the transmission power of the DAB and the voltage and displacement at both ends, considering the operating range of the microgrid bus voltage and the capacity constraint of the DAB, and combining the equivalent droop model of the ports of the DC microgrids on both sides, the forward transmission power ( P DC-SOP >0) and reverse transmission power ( P DC-SOP The limiting expression for DC-SOP transmission power under the condition of <0): Step 3.1 When the power of DC-SOP P DC-SOP During forward transmission, the transmission power of DAB1 P Transmission power of 1 and DAB2 P Both 2 are greater than zero. Furthermore, the first DC microgrid outputs power through DAB1, and the second DC microgrid absorbs power through DAB2.

[0024] Step 3.1.1 Calculate the transmission power limit of DAB1 : The output power of the first DC microgrid isP out = P Since 1>0, the bus voltage can be obtained using equation (8). V 1: (8) In equation (8), V 1,0 This is the equivalent DC bus rated voltage of the first DC microgrid; P 1,N This represents the total output power of all constant power units within the first DC microgrid. m 1 represents the equivalent droop coefficient of the first DC microgrid.

[0025] The transmission power of DAB1 can be obtained using equation (9). P 1: (9) In equation (9), D 1∈[-0.5, 0.5].

[0026] because P 1= P 2>0, therefore D 1∈[0, 0.5]. Substituting equation (8) into equation (9), we obtain equation (10): (10) For equation (10), i.e., the function Perform monotonicity analysis on the function exist D The maximum value is obtained at 1=0.5. Therefore, the maximum transmission power of DAB1 considering control and capacity constraints can be obtained using equation (11). : (11) Assume the lower limit of the allowable bus voltage for the first DC microgrid is V 1,min Therefore, the maximum transmission power of DAB1 considering the bus voltage offset range constraint can be obtained using equation (12). : (12) Therefore, when DC-SOP power is transmitted in the forward direction, the transmission power limit of DAB1 can be obtained from equation (13). : (13) Step 3.1.2 Calculate the transmission power limit of DAB2 : The output power of the second DC microgrid is Pout =- P Since 2 < 0, the bus voltage can be obtained using equation (14). V 2: (14) In equation (14), V 2,0 This is the equivalent DC bus rated voltage of the second DC microgrid; P 2,N This represents the total output power of all constant power units within the second DC microgrid. m 2 represents the equivalent droop coefficient of the second DC microgrid.

[0027] The transmission power of DAB2 can be obtained using equation (15). P 2: (15) In equation (15), D 2∈[-0.5, 0.5].

[0028] because P 1= P 2>0, therefore D 1∈ D 2∈[0, 0.5]. Substituting equation (14) into equation (15), we obtain equation (16): (16) For equation (16), i.e., the function Perform monotonicity analysis, when When, function exist D The maximum value is obtained at 2=0.5. Therefore, using equation (17), the maximum transmission power of DAB2 considering control and capacity constraints can be obtained. : (17) when At that time, the transmission power limit is determined by the upper voltage limit.

[0029] Assume the upper limit of the allowable bus voltage for the second DC microgrid is V 2,max Therefore, the maximum transmission power of DAB2 considering the bus voltage offset range constraint can be obtained using equation (18). : (18) Therefore, when DC-SOP power is transmitted in the forward direction, the transmission power limit of DAB2 can be obtained from equation (19). : (19) DC-SOP forward power transfer Limited by the DAB1 and DAB2 limits, i.e. .

[0030] Step 3.2 When the power of DC-SOP P DC-SOP During reverse transmission, the transmission power of DAB1 P Transmission power of 1 and DAB2 P Both 2 are less than zero. Furthermore, the first DC microgrid absorbs power through DAB1, and the second DC microgrid outputs power through DAB2.

[0031] Step 3.2.1 Calculate the absolute value of the transmission power limit of DAB1. : The output power of the first DC microgrid is P out =-| P 1|<0, so the bus voltage can be obtained using equation (20). V 1: (20) The transmission power of DAB1 can be obtained using equation (21). P 1: (twenty one) In equation (21), D 1∈[-0.5, 0.5].

[0032] because P 1= P 2 < 0, therefore D 1∈[-0.5, 0]. Substituting equation (20) into equation (21), we obtain the relation (22): (twenty two) For equation (22), i.e., the function Perform monotonicity analysis, when When, function exist D The maximum value is obtained at 1 = -0.5. Therefore, the maximum transmission power of DAB1 considering control and capacity constraints can be obtained using equation (21). : (twenty one) when At that time, the transmission power limit is determined by the upper voltage limit.

[0033] Assume the upper limit of the allowable bus voltage for the first DC microgrid is V 1,maxTherefore, the maximum transmission power of DAB1 considering the bus voltage offset range constraint can be obtained using equation (22). : (twenty two) Therefore, when DC-SOP power is transmitted in reverse, the transmission power limit of DAB1 can be obtained from equation (23). : (twenty three) Step 3.2.2 Calculate the transmission power limit of DAB2 : The output power of the second DC microgrid is P out =| P Since 2|>0, the bus voltage can be obtained using equation (24). V 2: (twenty four) The transmission power of DAB2 can be obtained using equation (25). P 2: (25) In equation (25), D 2∈[-0.5, 0.5].

[0034] because P 1= P 2 < 0, therefore D 2∈[-0.5, 0]. Substituting equation (24) into equation (25), we obtain the relation (26): (26) For equation (26), i.e., the function Perform monotonicity analysis on the function exist D The maximum value is obtained at 2 = -0.5. Therefore, using equation (27), the maximum transmission power of DAB2 considering control and capacity constraints can be obtained. : (27) Assume the lower limit of the allowable bus voltage for the second DC microgrid is V 2,min Therefore, the maximum transmission power of DAB2 considering the bus voltage offset range constraint can be obtained using equation (28). : (28) Therefore, when DC-SOP power is transmitted in reverse, the transmission power limit of DAB1 can be obtained from equation (29). : (29) DC-SOP reverse transmission power absolute value Limited by the DAB1 and DAB2 limits, i.e., the absolute value of DC-SOP reverse transmission power. .

[0035] Step 4. This power limit derivation method is not limited to the structure of two microgrids interconnected by DC-SOP. A schematic diagram illustrating its widespread application in multi-DAB parallel microgrid groups is shown below. Figure 5 As shown, multiple constant-power DABs are connected in parallel on a common DC bus, with each DAB connected to a droop-controlled DC microgrid. The zeroth dual active bridge converter (DAB0) connects to a large-capacity microgrid or DC distribution network, employing constant-voltage control to maintain the bus voltage. V dc The remaining DABs (DAB1, DAB2, ..., DAB) n All microgrids employ constant power control and are connected to microgrid 1, microgrid 2, ... microgrids respectively. n The external characteristics of each microgrid port can also be described by the equivalent model described in step 2. Each microgrid can independently adjust its transmission power, exhibiting excellent scalability.

[0036] Step 4.1 For any microgrid k ( k =1,2,…, n Using equation (30) to represent microgrids k Equivalent droop coefficient : (30) In equation (30), m k,i It is a micro-network k The i The droop coefficient of each DG.

[0037] Using equation (31) to represent microgrids k Equivalent DC bus rated voltage : (31) In equation (31), V k,i0 For micro-network k The i The rated voltage of the busbar of each DG.

[0038] Using equation (32) to represent microgrids k Total output of internal constant power unit : (32) In equation (32), P k,j For micro-network k The j Output power of each constant power unit.

[0039] Step 4.2 Microgrid k The output power is P k , Indicates power from microgrid k Flowing to the common bus, This indicates that power flows from the common bus to the microgrid. k Micronet k Output power limit and power absorption limit The general formulas (33) and (34) are given respectively: (33) (34) In equations (33) and (34), K k = n k / f sk L k To cooperate with microgrids k Connected DAB k Parameter-related constants; f sk For DAB k The switching frequency; n k For DAB k The turns ratio of the primary to the secondary side of the transformer; L k For DAB k The sum of the transformer leakage inductance and the applied inductance; V k,0 For micro-network k The equivalent rated voltage of the DC bus; V k,min For micro-network k Permissible lower limit of bus voltage; V k,max For micro-network k The maximum allowable bus voltage; P k,N This represents the total output power of all constant power units in the first DC microgrid. m k Let k be the equivalent droop coefficient of the first DC microgrid; therefore, the feasible power range for a single microgrid k is... .

[0040] Ignoring DAB losses, the power balance equation for the common DC bus is expressed by equation (35): (35) In equation (35), The output power of the system connected to the constant voltage DAB0 (referred to as the "main system", which can be a strong microgrid or a DC distribution network) is defined as flowing out of the system in the positive direction.

[0041] The main system has a power limit, denoted as its output limit. The absorption limit is The total power of all independent microgrids with constant-power DAB connections is limited to the power capacity of the main system. If the upper-layer scheduler specifies a total power target... The overall transmission power limit of a multi-DAB interconnected micronet group is given by equation (36): (36) In this embodiment, an electronic device includes a memory and a processor. The memory stores a program that supports the processor in executing the above-described method, and the processor is configured to execute the program stored in the memory.

[0042] In this embodiment, a computer-readable storage medium stores a computer program, which is executed by a processor to perform the steps of the above method.

Claims

1. A method for calculating the transmission power limit of a soft-switching device in a DC microgrid group, characterized in that, Includes the following steps: Step 1: Establish a DC soft-switching device DC-SOP consisting of a first dual active bridge converter DAB1 and a second dual active bridge converter DAB2 connected back-to-back. DAB1 is connected to the first DC microgrid and uses constant voltage control to maintain a constant common DC bus voltage. DAB2 is connected to the second DC microgrid and uses constant power control to achieve power transmission. Step 2: Taking the output power direction of any DC microgrid as positive, perform internal aggregation on each DC microgrid to establish its port equivalent droop control model; Step 3: Based on the relationship between the transmission power of DAB1 and DAB2 and the voltage and displacement ratio at both ends, and considering the voltage operating range of the DC microgrid bus and the capacity constraints of the dual active bridge converter, a limit expression for the transmission power of DC-SOP is constructed based on the port equivalent droop model of the DC microgrid on both sides, under the conditions of forward transmission power and reverse transmission power.

2. The method for calculating the transmission power limit of a soft-switching device in a DC microgrid group according to claim 1, characterized in that, Step 2 involves using equation (2) to construct the port equivalent droop control model of the DC microgrid on either side: (2) In formula (2): V The bus voltage of either side of the DC microgrid; V 0,eq The equivalent rated voltage of the DC bus on either side of the DC microgrid; m eq The equivalent droop coefficient of the DC microgrid on either side; P out The power output from either side of the DC microgrid to the DC-SOP; P N This represents the total output power of all constant power units in any DC microgrid on either side.

3. The method for calculating the transmission power limit of a soft-switching device in a DC microgrid group according to claim 1, characterized in that, Step 3 includes: When the power of DC-SOP P DC-SOP During forward transmission, the first DC microgrid outputs power through DAB1, and the second DC microgrid absorbs power through DAB2. The forward transmission power limit of DAB1 is determined using equations (13) and (19), respectively. P + 1,max and the forward transfer power limit of DAB2 P + 2,max Thus, the forward transfer power limit of DC-SOP is obtained. : (13) (19) In equations (2) and (3), K 1= n 1 / f s1 L 1, K 2= n 2 / f s2 L 2 represents constants related to the parameters of DAB1 and DAB2, respectively; f s1 , f s2 These are the switching frequencies of DAB1 and DAB2, respectively. n 1, n 2 represents the turns ratio of the primary and secondary sides of transformers DAB1 and DAB2, respectively; L 1, L 2 represents the sum of the transformer leakage inductance and the external inductance of DAB1 and DAB2, respectively; V dc The voltage of the common DC bus; V 1,0 This is the equivalent rated voltage of the DC bus of the first DC microgrid; V 2,0 This is the equivalent rated voltage of the DC bus of the second DC microgrid; V 1,min This is the lower limit of the allowable bus voltage for the first DC microgrid; V 2,max This is the upper limit of the allowable bus voltage for the second DC microgrid; P 1,N This represents the total output power of all constant power units in the first DC microgrid. P 2,N This represents the total output power of all constant power units in the second DC microgrid. m 1 represents the equivalent droop coefficient of the first DC microgrid; m 2 represents the equivalent droop coefficient of the second DC microgrid; When the power of DC-SOP P DC-SOP During reverse transmission, the first DC microgrid absorbs power through DAB1, and the second DC microgrid outputs power through DAB2. Equations (23) and (29) are used to determine the absolute value of the reverse transmission power limit of DAB1, respectively. P - 1,max |Absolute value of the reverse transfer power limit of DAB2| P - 2,max | Thus, the absolute value of the reverse transfer power limit of DC-SOP is obtained. : (23) (29) In equations (23) and (29): V 1,max This is the upper limit of the allowable bus voltage for the first DC microgrid; V 2,min This is the lower limit of the allowable bus voltage for the second DC microgrid.

4. An electronic device, comprising a memory and a processor, characterized in that, The memory is used to store a program that supports a processor in executing the method of any one of claims 1-3, the processor being configured to execute the program stored in the memory.

5. A computer-readable storage medium storing a computer program thereon, characterized in that, The computer program is executed by the processor to perform the steps of the method according to any one of claims 1-3.

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