Mode switching scheduling control method and device for direct-current micro-grid

Abstract

The invention relates to the technical field of power grids, in particular to a mode switching scheduling control method and device for a direct-current micro-grid, and the method comprises the steps: determining a plurality of operation modes of a target direct-current micro-grid system based on the target direct-current micro-grid system and the direct-current bus voltage of the target direct-current micro-grid system; establishing a switching system model based on the multiple operation modes of the target DC micro-grid system so as to obtain an analysis result of mode switching stability through the switching system model; and determining a stability domain of the target operation mode according to an analysis result so as to introduce at least one transition operation mode to determine a mode switching scheduling strategy of the target DC micro-grid system. When the operation mode of the DC micro-grid system is switched, the system track is changed by adjusting the switching strategy, the positive feedback instability caused by the voltage drop of the DC bus in the switching process is eliminated, the problem of large fluctuation of the system voltage is solved, and the stability and reliability of the DC micro-grid are improved.

Description

Technical Field

[0001] The present application relates to the technical field of power grids, and particularly relates to a method and device for mode switching scheduling control of a DC microgrid. Background Art

[0002] With the rapid development of distributed energy resources and power electronics technology, DC microgrids have received extensive attention due to their high efficiency and flexibility. For example, in deep space exploration missions such as lunar research stations and manned bases, or in scenarios such as data centers and multi-electric aircraft, DC microgrids including various forms of distributed power sources such as photovoltaic arrays, small generators, and small modular nuclear reactors, as well as energy storage devices such as batteries and fuel cells, are the core energy architectures.

[0003] In related technologies, to achieve power management and resource coordination of DC microgrids, bus voltage signals are widely used as a decentralized control strategy. This strategy is based on local measurements and has the advantage of not requiring real-time communication. A DC microgrid can adapt to changes in the DC bus voltage by switching different operating modes, and each operating mode corresponds to a specific voltage range and a set of control methods.

[0004] However, the DC microgrid control methods in related technologies mostly focus on the stability optimization in a single operating mode, ignoring the dynamic coupling effect during the mode switching process, unable to cope with the voltage instability caused by mode switching, difficult to achieve lightweight real-time control, and difficult to ensure the stability and reliability of the DC microgrid. For example, in deep space exploration missions, when switching from lunar day to lunar night, the sudden drop in the bus voltage may cause the system trajectory to deviate from the stable region of the target operating mode, triggering positive feedback voltage instability, threatening the power supply safety of key loads such as life support systems and temperature control equipment, difficult to cope with the extreme lunar surface conditions, and lacking an adaptability design for lunar surface resource constraints (such as low communication bandwidth and limited computing power), and thus urgently needs to be improved and perfected. Summary of the Invention

[0005] The present application provides a method and device for mode switching scheduling control of a DC microgrid to solve the problems that the DC microgrid control methods in related technologies ignore the dynamic coupling effect existing during the mode switching process, are unable to cope with the voltage instability caused by mode switching of the DC microgrid, difficult to achieve lightweight real-time control, and insufficient in adaptability to resource constraints.

[0006] An embodiment of the first aspect of the present application provides a mode switching scheduling control method for a DC microgrid, including the following steps: determining multiple operating modes of the target DC microgrid system based on the target DC microgrid system and its DC bus voltage; establishing a corresponding switching system model for the target DC microgrid system based on the multiple operating modes of the target DC microgrid system, so as to obtain an analysis result of the mode switching stability of the target DC microgrid system through the switching system model; determining a stable region of the target operating mode of the target DC microgrid system according to the analysis result, and detecting the real-time voltage of the target DC microgrid system, so as to determine a mode switching scheduling strategy for the target DC microgrid system based on the current operating mode, the stable region and at least one transition operating mode of the target DC microgrid system when the real-time voltage reaches a voltage threshold and the stable region meets a preset condition, and controlling the target DC microgrid system to execute the mode switching scheduling strategy.

[0007] Optionally, in an embodiment of the present application, the determining multiple operating modes of the target DC microgrid system based on the target DC microgrid system and its DC bus voltage includes: obtaining the rated DC bus voltage and the operating voltage range of the target DC microgrid system; determining multiple operating modes of the target DC microgrid system according to the rated DC bus voltage and the operating voltage range.

[0008] Optionally, in an embodiment of the present application, the establishing a corresponding switching system model for the target DC microgrid system based on the multiple operating modes of the target DC microgrid system includes: determining a simplified system corresponding to the target DC microgrid system according to the equivalent characteristics of the power supply and load of the target DC microgrid system; analyzing at least one component element of the simplified system to model the at least one component element to determine the state equation corresponding to the target DC microgrid system; establishing a corresponding switching system model for the target DC microgrid system based on the multiple operating modes of the target DC microgrid system and the state equation corresponding to the target DC microgrid system.

[0009] Optionally, in an embodiment of the present application, the obtaining an analysis result of the mode switching stability of the target DC microgrid system through the switching system model includes: calculating the stable equilibrium points and stable regions of the target DC microgrid system under the multiple operating modes of the target DC microgrid system based on the switching system model; analyzing the mode switching stability of the target DC microgrid system according to the stable equilibrium points and stable regions under the multiple operating modes to obtain the analysis result.

[0010] Optionally, in an embodiment of the present application, determining the mode switching scheduling strategy of the target DC microgrid system based on the current operating mode, the stability region, and at least one transition operating mode of the target DC microgrid system includes: selecting at least one transition operating mode from the multiple operating modes and / or multiple pre-established transition operating modes based on the current operating mode and the stability region of the target DC microgrid system; and determining the mode switching scheduling strategy through the at least one transition operating mode.

[0011] Optionally, in an embodiment of the present application, the expression of the switching system model is:

[0012] x = f σ (x), σ = {1, 2, 3, 4},

[0013]

[0014] where x is the slow state variable of the second-order reduced-order model of the state equation, and f σ : σ ∈ S is a set of continuous functions representing the dynamic equations of each mode; S = {1, 2,..., 4} is an index set used to characterize the discrete state of the system; σ: [0, ∞) → S is a piecewise constant function whose value is in the set S, representing the switching signal of the system; [V1, V4] is the voltage range for the normal operation of the DC microgrid, v bus is the DC bus voltage, and V N is the rated voltage.

[0015] An embodiment of the second aspect of the present application provides a mode switching scheduling control device for a DC microgrid, including: a determination module for determining multiple operating modes of the target DC microgrid system based on the target DC microgrid system and its DC bus voltage; an establishment module for establishing a switching system model corresponding to the target DC microgrid system based on the multiple operating modes of the target DC microgrid system, so as to obtain an analysis result of the mode switching stability of the target DC microgrid system through the switching system model; and a control module for determining the stability region of the target operating mode of the target DC microgrid system according to the analysis result, and detecting the real-time voltage of the target DC microgrid system, so as to determine the mode switching scheduling strategy of the target DC microgrid system based on the current operating mode, the stability region, and at least one transition operating mode when the real-time voltage reaches the voltage threshold and the stability region meets the preset conditions, and controlling the target DC microgrid system to execute the mode switching scheduling strategy.

[0016] Optionally, in an embodiment of the present application, the determining module includes: an obtaining unit configured to obtain the rated DC bus voltage and the operating voltage range of the target DC microgrid system; a first determining unit configured to determine multiple operating modes of the target DC microgrid system according to the rated DC bus voltage and the operating voltage range.

[0017] Optionally, in an embodiment of the present application, the establishing module includes: a second determining unit configured to determine a simplified system corresponding to the target DC microgrid system according to the equivalent characteristics of the power supply and load of the target DC microgrid system; a modeling unit configured to analyze at least one component element of the simplified system to model the at least one component element to determine a state equation corresponding to the target DC microgrid system; an establishing unit configured to establish a switching system model corresponding to the target DC microgrid system based on multiple operating modes of the target DC microgrid system and the state equation corresponding to the target DC microgrid system.

[0018] Optionally, in an embodiment of the present application, the establishing module includes: a calculating unit configured to calculate, based on the switching system model, the stable equilibrium points and the stable regions of the target DC microgrid system under multiple operating modes of the target DC microgrid system; an analyzing unit configured to analyze the mode switching stability of the target DC microgrid system according to the stable equilibrium points and the stable regions under the multiple operating modes to obtain the analysis result.

[0019] Optionally, in an embodiment of the present application, the control module includes: a selecting unit configured to select at least one transition operating mode from the multiple operating modes and / or multiple pre-established transition operating modes based on the current operating mode and the stable region of the target DC microgrid system to determine the mode switching scheduling strategy through the at least one transition operating mode.

[0020] Optionally, in an embodiment of the present application, the expression of the switching system model is:

[0021] x = f σ (x), σ = {1, 2, 3, 4},

[0022]

[0023] where x is the slow state variable of the second-order reduced-order model of the state equation, f σ: σ ∈ S is a set of continuous functions representing the dynamic equations of each mode; S = {1, 2, …, 4} is an index set used to characterize the discrete states of the system; σ: [0, ∞) → S is a piecewise constant function whose values are in the set S, representing the switching signal of the system; [V1, V4] is the voltage range for the normal operation of the DC microgrid, v bus is the DC bus voltage, and V N is the rated voltage.

[0024] The third aspect of the present application provides an electronic device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor. The processor executes the program to implement the mode switching scheduling control method of the DC microgrid as described in the above embodiments.

[0025] The fourth aspect of the present application provides a computer-readable storage medium storing a computer program, and when the program is executed by a processor, it implements the mode switching scheduling control method of the DC microgrid as described above.

[0026] The fifth aspect of the present application provides a computer program product including a computer program, and when the computer program is executed, it is used to implement the mode switching scheduling control method of the DC microgrid as described above.

[0027] The embodiments of the present application can analyze the influence of the stable equilibrium point and stable region of the operating mode on the stability of the target DC microgrid system according to the operating mode of the target DC microgrid system, and introduce at least one transitional operating mode to control the DC microgrid system to perform mode switching according to the analysis results. Thus, it realizes changing the system trajectory by adjusting the mode switching process of the target DC microgrid system, effectively guiding the system trajectory into the stable region of the target operating mode, reducing the positive feedback instability caused by the DC bus voltage drop during the switching process. Moreover, the implementation of the present application is simple, without any modification to the system hardware structure, and can be achieved only by optimizing the switching strategy and introducing a transitional operating mode, which can make the controller design more concise and efficient, reduce the system complexity, and have good economy and operability; and the present application can real-time monitor the key variables of the DC bus voltage that trigger mode switching, thereby realizing real-time and precise control of the system operation process, improving the stability and reliability of the DC microgrid. Thus, it solves the problems in the related DC microgrid control methods that ignore the dynamic coupling effect during the mode switching process, cannot cope with the voltage instability caused by mode switching in the DC microgrid, are difficult to achieve lightweight real-time control, and have insufficient adaptability to resource constraints.

[0028] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, where:

[0030] Figure 1 is a flowchart of a method for mode switching scheduling control of a DC microgrid according to an embodiment of the present application;

[0031] Figure 2 is a schematic diagram of the operating mode switching principle of an embodiment of the present application;

[0032] Figure 3 is a control block diagram of the operating mode switching of an embodiment of the present application;

[0033] Figure 4 is a schematic diagram of the comparison of simulation results of an embodiment of the present application;

[0034] Figure 5 is a schematic structural diagram of a mode switching scheduling control device for a DC microgrid according to an embodiment of the present application;

[0035] Figure 6 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

[0036] REFERENCE SIGNS:

[0037] 10 - Mode switching scheduling control device of the DC microgrid: 100 - Determination module, 200 - Establishment module, and 300 - Control module; 601 - Memory, 602 - Processor, and 603 - Communication interface. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] Embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application.

[0039] The following describes a method and device for mode - switching scheduling control of a DC micro - grid according to an embodiment of the present application. In view of the problem in the related art of the DC micro - grid control method mentioned in the above - mentioned background art that ignores the dynamic coupling effect existing in the mode - switching process, cannot cope with the voltage instability caused by mode - switching in the DC micro - grid, is difficult to achieve lightweight real - time control, and has insufficient adaptability to resource constraints, the present application provides a method for mode - switching scheduling control of a DC micro - grid. In this method, according to the operating mode of the target DC micro - grid system, the stable equilibrium point and the stable region of the operating mode are analyzed to determine the influence on the stability of the target DC micro - grid system, so as to introduce at least one transitional operating mode according to the analysis result to control the DC micro - grid system to perform mode - switching. Thus, by adjusting the mode - switching process of the target DC micro - grid system, the system trajectory is changed, effectively guiding the system trajectory into the stable region of the target operating mode, reducing the positive - feedback instability caused by the DC bus voltage drop during the switching process. Moreover, the implementation of the present application is simple, without any modification to the system hardware structure, and can be achieved only by optimizing the switching strategy and introducing a transitional operating mode, which can make the controller design more concise and efficient, reduce the system complexity, and has good economy and operability; and the present application can real - time monitor the key variables of the DC bus voltage that trigger mode - switching, thereby realizing real - time and accurate control of the system operation process, improving the stability and reliability of the DC micro - grid. Thus, the problems in the related art of the DC micro - grid control method, such as ignoring the dynamic coupling effect existing in the mode - switching process, being unable to cope with the voltage instability caused by mode - switching in the DC micro - grid, being difficult to achieve lightweight real - time control, and having insufficient adaptability to resource constraints, are solved.

[0040] Specifically, Figure 1 FIG. is a flowchart of a method for mode - switching scheduling control of a DC micro - grid provided by an embodiment of the present application.

[0041] As Figure 1 shown, the mode - switching scheduling control method of the DC micro - grid includes the following steps:

[0042] In step S101, based on the target DC micro - grid system and its DC bus voltage, multiple operating modes of the target DC micro - grid system are determined.

[0043] Those skilled in the art can understand that the target DC microgrid system here refers to a DC microgrid system composed of three core elements: distributed power sources, energy storage units, and loads. This system adopts an expandable design and can integrate various types of energy subsystems, including but not limited to distributed power sources in various forms such as photovoltaic arrays, small generators, small modular nuclear reactors, etc.; as well as various energy storage devices such as batteries and fuel cells, and various load devices. These energy subsystems are interconnected through a DC bus to form a unified DC microgrid. This system is particularly suitable for special environments in deep space exploration missions, such as lunar research stations and manned bases, as well as key scenarios such as data centers, providing a highly reliable DC power supply architecture for these applications.

[0044] In some embodiments, the DC microgrid system may have other components in addition to the photovoltaic array, energy storage unit, and load. For example, an energy conversion device and a control and protection device, etc. The operating modes of DC microgrid systems with different components will also be different, and the number of DC buses connected to the DC microgrid system may also vary, which may be a single bus or a double bus.

[0045] Due to different system compositions and the number of DC buses, the operating modes of different DC microgrid systems may also be different. In order to better perform switching control on the target DC microgrid system, the embodiments of the present application can first determine various operating modes of the target DC microgrid system according to the target DC microgrid system and its DC bus voltage.

[0046] Taking a three-machine DC microgrid system that only includes a photovoltaic array, an energy storage unit, and a constant-power load as an example, the present application can divide different operating modes according to the DC bus voltage of the three-machine DC microgrid system. For example, operating mode 1, operating mode 2, operating mode 3, and so on. In different operating modes, the three-machine DC microgrid system may adopt different control strategies.

[0047] The embodiments of the present application can better analyze the stability of the target DC microgrid system by determining the operating mode of the target DC microgrid system, so as to more simply and clearly understand the implementation process of the mode switching scheduling control of the target DC microgrid system.

[0048] Optionally, in an embodiment of the present application, based on the target DC microgrid system and its DC bus voltage, determining various operating modes of the target DC microgrid system includes: obtaining the rated DC bus voltage and the operating voltage range of the target DC microgrid system; determining various operating modes of the target DC microgrid system according to the rated DC bus voltage and the operating voltage range.

[0049] In some embodiments, when determining multiple operating modes of the target DC microgrid system based on the target DC microgrid system and its DC bus voltage, the present application may, but is not limited to, determine by obtaining the rated DC bus voltage and the operating voltage range of the target DC microgrid system.

[0050] Taking the three-machine DC microgrid system composed of a photovoltaic array, a battery energy storage system, and a constant power load as an example, the photovoltaic array and the battery energy storage system are respectively connected to the DC bus through a unidirectional and a bidirectional boost converter. When the output power of the photovoltaic array is greater than (or less than) the power consumed by the constant power load, the battery energy storage system is charged (or discharged). At this time, the coordinated operation of the DC microgrid system can be achieved through the DC bus signal strategy.

[0051] Assume that the rated DC bus voltage of the DC microgrid system is V N , and the voltage range for the normal operation of the DC microgrid system is [V1, V4]. Within different DC bus voltages v bus , the DC microgrid system has different operating modes, and the photovoltaic array and the battery energy storage system will adopt different control methods accordingly. For example, several common operating modes of the DC microgrid system are as follows:

[0052] Operating mode 1 (V2 ≤ v bus ≤ V1): At this time, v bus is close to its upper limit; the output P PV of the photovoltaic array is much greater than the power P CPL required by the constant power load; and at this time, the photovoltaic array adopts the maximum power point tracking control, and the battery energy storage is charged through constant voltage control to keep the converter output voltage constant and prevent v bus from overvoltage.

[0053] Operating mode 2 (V B ≤ v bus < V2): At this time, v bus is close to the rated value V N ; when P PV > P CPL , the excess energy will be stored in the battery energy storage system; and at this time, the photovoltaic array still adopts the maximum power point tracking control, and the battery energy storage adopts droop control for charging.

[0054] Operating mode 3 (V3 ≤ v bus < V N ): At this time, v bus is close to V N ; when P PV < P CPL , the battery energy storage system releases power to support the stable operation of the system; and at this time, the photovoltaic array still adopts the maximum power point tracking control, and the battery energy storage still adopts droop control for discharging.

[0055] Operating mode 4 (V4 ≤ v bus < V3): At this time, v bus approaches its lower limit; P PV is much smaller than P CPL ; and at this time, the photovoltaic array still adopts the maximum power point tracking control, and the battery energy storage system discharges through constant voltage control to prevent v bus from undervoltage.

[0056] Step S102: Based on multiple operating modes of the target DC microgrid system, establish a switching system model corresponding to the target DC microgrid system, so as to obtain the analysis result of the mode switching stability of the target DC microgrid system through the switching system model.

[0057] In some other embodiments, considering that the dynamic evolution process of the target DC microgrid system switching operating modes depends on the dynamic characteristics of various operating modes and the corresponding switching strategies, therefore, the present application can model the target DC microgrid system with multiple operating modes as a switching system.

[0058] Furthermore, in order to facilitate the analysis of the stability of the target DC microgrid system when switching multiple operating modes, the embodiments of the present application can, after modeling the target DC microgrid system as a switching system based on multiple operating modes of the target DC microgrid system, model the switching system, so as to establish a switching system model corresponding to the target DC microgrid system, so as to obtain the analysis result of the mode switching stability of the target DC microgrid system through the switching system model, that is, the characteristics and stability analysis result of the target DC microgrid system when switching multiple operating modes.

[0059] Those skilled in the art of this technology can understand that DC microgrids usually have grid-connected modes and island modes, etc. In the grid-connected mode, the DC microgrid is connected to the external large power grid and can exchange power with the large power grid. At this time, the operating characteristics of the system are affected by factors such as grid voltage and frequency; while in the island mode, the DC microgrid operates independently, does not depend on the external power network, and only relies on local renewable energy (such as photovoltaic arrays) and energy storage units to meet the load demand, and its operating characteristics mainly depend on its own power supply and load conditions.

[0060] Based on this, the embodiments of the present application can consider the equivalent characteristics of the power supply and load of the DC microgrid, simplify the multi-machine system into a two-machine system, and then model each component of the two-machine system. Subsequently, through the singular perturbation theory (a control theory used to deal with systems with fast-varying and slow-varying dynamic characteristics), the target DC microgrid system with different operating modes is transformed into a unified state equation with different parameters, so as to construct a switching system model of the DC microgrid system.

[0061] Then, the embodiments of the present application can analyze the mode switching stability of the target DC microgrid system based on this switching system model. Specifically, the embodiments of the present application can calculate the stable equilibrium points of the target DC microgrid system under different operating modes, and draw the stability regions of the target DC microgrid system under different operating modes according to the manifold theory.

[0062] Finally, the analysis result of the switching stability of the target DC microgrid system can be obtained as follows: there are stable equilibrium points in each operating mode of the target DC microgrid system, but when the target DC microgrid system switches between different operating modes, the initial stable equilibrium point may be located outside the stability region of the expected mode, thus causing system voltage instability. Here, the initial stable equilibrium point can be understood as the stable equilibrium point of the operating mode before switching to another operating mode.

[0063] Next, a further explanation will be given to the process of establishing the switching system model and the process of analyzing the mode switching stability of the embodiments of the present application.

[0064] Optionally, in an embodiment of the present application, based on multiple operating modes of the target DC microgrid system, a switching system model corresponding to the target DC microgrid system is established, including: determining a simplified system corresponding to the target DC microgrid system according to the equivalent characteristics of the power supply and load of the target DC microgrid system; analyzing at least one component element of the simplified system to model at least one component element to determine the state equation corresponding to the target DC microgrid system; based on multiple operating modes of the target DC microgrid system and the state equation corresponding to the target DC microgrid system, establishing a switching system model corresponding to the target DC microgrid system. The expression of the switching system model can be but not limited to:

[0065] x = f σ (x), σ = {1, 2, 3, 4},

[0066]

[0067] where x is the slow state variable of the second-order reduced-order model of the state equation, f σ : σ ∈ S is a set of continuous functions representing the dynamic equations of each mode; S = {1, 2,..., 4} is an index set used to characterize the discrete state of the system; σ: [0, ∞) → S is a piecewise constant function whose value is in the set S, representing the switching signal of the system; [V1, V4] is the voltage range for the normal operation of the DC microgrid, v bus is the DC bus voltage, and V N is the rated voltage.

[0068] Based on the relevant descriptions of other embodiments, it can be understood that based on the equivalent characteristics of the power supply and load of the DC microgrid, the multi-machine system in this application can be simplified into a two-machine system, and then each component of the two-machine system can be modeled.

[0069] In the actual implementation process, this application can determine the simplified system of the target DC microgrid system according to the equivalent characteristics of the power supply and load of the target DC microgrid system, and then analyze at least one component element of the simplified system to model at least one component element, thereby determining the state equation corresponding to the target DC microgrid system, and then establishing the switching system model corresponding to the target DC microgrid system. For example, the target DC microgrid system is simplified into a two-machine system, and then each component of the two-machine system is modeled to establish the switching system model corresponding to the target DC microgrid system.

[0070] For example, this application can first model the photovoltaic array and the constant power load as an equivalent constant power load. Among them, the photovoltaic array adopts the maximum power point tracking control and is regarded as a constant power source. The grid-connected impedance of the photovoltaic array is small enough to be ignored. From the perspective of the system, at this time, the photovoltaic array and the constant power load are equivalent to an equivalent constant power load, denoted by P e to represent the equivalent constant power load, and the expression can be but is not limited to the following:

[0071] P e =P cpl -P pv (1)

[0072] Then the current i e of the equivalent constant power load can be but is not limited to expressed as i e =P e / v bus .

[0073] When P e >0, it means that the equivalent constant power load consumes power; when P e <0, it means that the equivalent constant power load outputs power.

[0074] In addition, the control methods of the energy storage include droop (charge and discharge) control and constant voltage control. In the embodiments of this application, the constant voltage control can be but is not limited to regarded as a special case of the droop control, and at this time R d =0. Let the reference value of the voltage outer loop control be U oref , and the calculation formula can be but is not limited to expressed as:

[0075] U oref =U ref -R d i line (2)

[0076] Among them, U ref is the reference voltage in each mode; i line is the line current.

[0077] Then the model of the battery energy storage system can be but is not limited to being expressed as:

[0078]

[0079] Among them, d is the duty cycle, d = S i + k Pi (S v + k Pv (U oref - v bat ) - i bat ). S v and S i respectively represent the outputs of the outer - loop and inner - loop integral controllers of the battery energy storage system; i bat , v bat and U s respectively represent the output current of the energy storage, the capacitor voltage, and the rated voltage. L bat , C bat , L line , C bus and R line respectively correspond to the filter inductor, the filter capacitor, the line inductor, the bus capacitor, and the line resistance.

[0080] Based on the above - mentioned modeling, it can be obtained that the state equation of the target DC micro - grid system is of the sixth order, and its state variable x can be but is not limited to being expressed as: x = [S v , S i , i bat , v bat , i line , v bus T .

[0081] Based on the singular perturbation theory, after time - scale analysis, a second - order reduced - order model can be obtained. Among them, x = [S v , v bus T is the slow - state variable. The state equation of the reduced - order model can be but is not limited to being expressed as:

[0082]

[0083] Among them,

[0084]

[0085] Furthermore, considering that the target DC micro - grid system will be based on the bus voltage v bus ​​Switching between different modes, so its switching strategy is state-dependent. Therefore, the switching system corresponding to the target DC microgrid system in the embodiments of the present application can be modeled as:

[0086] x = f σ (x), σ = {1, 2, 3, 4},

[0087]

[0088] where f σ : σ ∈ S is a set of continuous functions representing the dynamic equations of each mode; S = {1, 2, …, 4} is an index set used to characterize the discrete states of the system; σ: [0, ∞) → S is a piecewise constant function whose values are in the set S, representing the switching signal of the system; the switching strategy determines the value of σ.

[0089] It should be noted that in the switching system model (6) corresponding to the target DC microgrid system, each mode can be uniformly represented by equations (4) and (5), but the specific parameters vary depending on the mode. For example:

[0090] Mode 1 (σ = 1), R d = 0, U ref = V2;

[0091] Mode 2 (σ = 2), R d = R d1 ,U ref = V N ;

[0092] Mode 3 (σ = 3), R d = R d2 ,U ref = V N ;

[0093] Mode 4 (σ = 4), R d = 0, U ref = V3.

[0094] Optionally, in an embodiment of the present application, the analysis result of the mode switching stability of the target DC microgrid system is obtained through the switching system model, including: calculating the stable equilibrium points and stable regions of the target DC microgrid system under various operating modes of the target DC microgrid system based on the switching system model; analyzing the mode switching stability of the target DC microgrid system according to the stable equilibrium points and stable regions under various operating modes to obtain the analysis result.

[0095] In some embodiments, when obtaining the analysis result of the mode switching stability of the target DC microgrid system by switching the system model, the present application mainly calculates the stable equilibrium points of the target DC microgrid under various operating modes according to the switched system model, and draws the stability regions of different operating modes according to the manifold theory. Then, the mode switching stability of the target DC microgrid system is analyzed based on the stable equilibrium points and stability regions.

[0096] Herein, the stable equilibrium point refers to the point at which the state of the target DC microgrid dynamic system can remain unchanged without external disturbances. The stability region refers to the set of all initial states where the target DC microgrid system can be attracted to a certain stable equilibrium point.

[0097] For example, the present application can first calculate the stable equilibrium points of the target DC microgrid system under various operating modes:

[0098] Still taking several common operating modes 1-4 of the DC microgrid system as an example, in operating modes 1 and 4, the equilibrium point x e exists and is unique.

[0099] x e = [S ve , v buse T = [P e / v bus , U ref T (7)

[0100] Then, calculate the Jacobian matrix J e of the reduced-order system of the target DC microgrid at the equilibrium point x e :

[0101]

[0102] As can be seen from Equation (8), all the eigenvalues of the target DC microgrid system at x e are positive, so the equilibrium points in operating modes 1 and 4 are stable equilibrium points.

[0103] In operating modes 2 and 3, if holds, then the target DC microgrid system has two equilibrium points, which can be expressed as follows:

[0104]

[0105] Among them, the high-voltage stable equilibrium point x e1 is a stable equilibrium point, and the low-voltage stable equilibrium point x e2 is an unstable equilibrium point.

[0106] Based on the stable equilibrium point obtained here, the embodiments of the present application can calculate the corresponding stable region by using the backstepping integral method.

[0107] As can be seen from the above analysis, there is a stable equilibrium point in the target DC microgrid system under each operating mode. If the target DC microgrid system always operates at this stable equilibrium point, it can always maintain stability. However, the independent stable equilibrium points of each operating mode cannot ensure the stability of the target DC microgrid system during the operating mode switching process. Therefore, the embodiments of the present application also need to further analyze its stability by examining the system trajectory of the target DC microgrid system when switching operating modes.

[0108] Those skilled in the art of this technology can understand that in a DC microgrid, the equivalent constant power load step is a large disturbance, which will cause changes in the DC bus voltage. During this transient process, the target DC microgrid system will switch operating modes, that is, the target DC microgrid system has different operating modes within different voltage ranges. When the DC microgrid system switches operating modes, its state equation will also change accordingly, resulting in a continuous but non-smooth manifold system trajectory and stable region in the target DC microgrid system during the operating mode switching process.

[0109] For example, the stable equilibrium point of the operating mode of the target DC microgrid system before the equivalent constant power load step, that is, before switching the operating mode, is called the initial stable equilibrium point. After the equivalent constant power load step, the system trajectory of the target DC microgrid system will move according to the dynamic equation (4). Based on this, the embodiments of the present application can draw the corresponding stable region according to the stable equilibrium point of the operating mode.

[0110] Then, based on the above content, it can be analyzed that the necessary and sufficient condition for the stability of the target DC microgrid system is that the stable region of the operating mode to which the target DC microgrid system is about to switch can cover the initial stable equilibrium point; if the stable region of the operating mode to which the target DC microgrid system is about to switch may not be able to cover the initial stable equilibrium point, the target DC microgrid system may become unstable at this time.

[0111] Step S103, determine the stable region of the target operating mode of the target DC microgrid system according to the analysis result, and detect the real-time voltage of the target DC microgrid system, so as to determine the mode switching scheduling strategy of the target DC microgrid system based on the current operating mode, stable region and at least one transition operating mode of the target DC microgrid system when the real-time voltage reaches the voltage threshold and the stable region meets the preset conditions, and control the target DC microgrid system to execute the mode switching scheduling strategy.

[0112] Based on the related descriptions of other embodiments, it can be understood that the DC bus voltage is an important state variable reflecting the system stability. When the change in the DC bus voltage exceeds a certain range, the target DC microgrid system will switch its operating mode. However, since the change in the DC bus voltage is small, the stability of the system can still be maintained. Once the DC bus voltage deviates significantly from the rated value, not only will the target DC microgrid system switch its operating mode, but it is very likely to become unstable during the switching process.

[0113] In some embodiments, in order to keep the target DC microgrid system stable during the process of switching its operating mode when the DC bus voltage deviates significantly from the rated value, the present application can determine the stability region of the target operating mode of the target DC microgrid system based on the above analysis results. Then, when it is detected that the real-time voltage (real-time DC bus voltage) of the target DC microgrid system reaches the voltage threshold and the stability region meets the preset conditions, at least one transitional operating mode is introduced, and the at least one transitional operating mode is used to guide the system trajectory to smoothly enter the stability region of the target operating mode, so as to control the target DC microgrid system to complete a stable operating mode switch.

[0114] Among them, the target operating mode can be understood here as the operating mode that the target DC microgrid system is about to switch to when the real-time voltage reaches the voltage threshold and causes a mode switch; the voltage threshold can be understood here as the voltage critical value that can cause the target DC microgrid system to be likely to become unstable during the process of switching its operating mode, and can be set by those skilled in the art according to experience or simulation results. For example, 90% etc., and the embodiments of the present application do not make specific limitations; the preset conditions can be understood here as that the stability region of the target operating mode cannot cover the stable equilibrium point of the current operating mode.

[0115] For example, Figure 2 is the schematic diagram of the operating mode switch for an embodiment of the present application. As Figure 2 shown, in the embodiments of the present application, when the stability region of the target operating mode cannot cover the stable equilibrium point of the current operating mode, at least one transitional operating mode can be introduced to guide the system trajectory of the target DC microgrid system to smoothly enter the stability region of the target operating mode, so that the target DC microgrid system can stably switch from the current operating mode to the target operating mode.

[0116] First, the embodiments of the present application can calculate the stability region of the target operating mode to determine the stable equilibrium points that can be covered by the stability region of the target operating mode, and then determine and introduce the corresponding at least one transitional operating mode according to the stable equilibrium points. That is, the stable equilibrium points of the transitional operating mode should conform to the stable equilibrium points that can be covered by the stability region of the target operating mode.

[0117] Therefore, when the control target DC microgrid system switches from the transitional operation mode to the target operation mode in the embodiments of the present application, since the stability domain of the target operation mode can cover the stable equilibrium point of the transitional operation mode, it can be ensured that the target DC microgrid system remains stable during the process of switching from the transitional operation mode to the target operation mode.

[0118] Moreover, in order to ensure that the target DC microgrid system also remains stable when switching from the current operation mode to the transitional operation mode, the embodiments of the present application can also calculate the stability domain of the transitional operation mode to ensure that the stability domain of the transitional operation mode can cover the stable equilibrium point of the current operation mode.

[0119] Therefore, when the control target DC microgrid system switches from the current operation mode to the transitional operation mode in the embodiments of the present application, since the stability domain of the transitional operation mode covers the stable equilibrium point of the current operation mode, it can also be ensured that the target DC microgrid system remains stable during the process of switching from the current operation mode to the transitional operation mode.

[0120] At this time, the embodiments of the present application can achieve that the target DC microgrid system remains stable when switching from the current operation mode to the transitional operation mode and also remains stable during the process of switching from the transitional operation mode to the target operation mode, thereby realizing the stability of the entire mode switching process of the target DC microgrid system from the current operation mode to the target operation mode.

[0121] Then, the mode switching scheduling strategy of the target DC microgrid system at this time is for the target DC microgrid system to switch from the current operation mode to the transitional operation mode and then to the target operation mode, and the target DC microgrid system can be controlled to execute this strategy.

[0122] Therefore, the embodiments of the present application have completed guiding the system trajectory of the target DC microgrid system to smoothly enter the stability domain of the target operation mode through at least one transitional operation mode, realizing that the target DC microgrid system stably switches from the current operation mode to the transitional operation mode, and then stably switches from the transitional operation mode to the target operation mode. The ultimate effect achieved is that the target DC microgrid system stably switches from the current operation mode to the target operation mode.

[0123] It should be noted that in the actual execution process, it is not necessarily possible to complete the stable switching of the target DC microgrid system from the current operation mode to the target operation mode through one transitional operation mode. At this time, the embodiments of the present application can introduce multiple transitional operation modes to complete the stable switching of the target DC microgrid system from the current operation mode to the target operation mode.

[0124] For example, in this application, it is also possible to first calculate the stability region of the target operating mode and calculate the stable equilibrium points that can be covered by the stability region of the target operating mode. However, if the transitional operating mode A where the stable equilibrium point is located cannot cover the stable equilibrium point of the current operating mode, then the stability regions and stable equilibrium points of transitional operating modes B, C, etc. can be calculated sequentially. The calculation rule is to calculate the transitional operating mode B corresponding to the stable equilibrium point that can be covered by the stability region of transitional operating mode A, and then calculate whether the stability region of transitional operating mode B can cover the stable equilibrium point of the current operating mode, that is, the stability region of each transitional operating mode needs to cover the stable equilibrium point of the previous operating mode.

[0125] If the stability region of transitional operating mode B can cover the stable equilibrium point of the current operating mode, the mode switching scheduling strategy at this time is that the target DC microgrid system first switches from the current operating mode to transitional operating mode B, then from transitional operating mode B to transitional operating mode A, and then from transitional operating mode A to the target operating mode. Control the target DC microgrid system to execute the switching of the operating mode according to this mode switching scheduling strategy.

[0126] If the stability region of transitional operating mode B still cannot cover the stable equilibrium point of the current operating mode, continue the calculation until the stability region of the last transitional operating mode can cover the stable equilibrium point of the current operating mode.

[0127] Thus, it is also possible to stably switch between multiple transitional operating modes through the target DC microgrid system, and achieve a stable switch from the current operating mode to the target operating mode.

[0128] It should be noted that when the real-time voltage (real-time DC bus voltage) of the target DC microgrid system does not reach the voltage threshold, although the target DC microgrid system will perform mode switching, it can also maintain a certain stability. Therefore, this application does not make specific restrictions on the mode switching scheduling strategy in this state, which can be determined by those skilled in the art according to actual application requirements, or directly control the target DC microgrid system to switch the operating mode according to the change of voltage, that is, directly switch from the current operating mode to the target operating mode, or in order to ensure that the target DC microgrid system will definitely not become unstable, at least one transitional mode is also set in this case.

[0129] Optionally, in an embodiment of the present application, based on the current operating mode, stability region, and at least one transitional operating mode of the target DC microgrid system, a mode switching scheduling strategy for the target DC microgrid system is determined, including: based on the current operating mode and stability region of the target DC microgrid system, at least one transitional operating mode is selected from multiple operating modes and / or multiple pre-established transitional operating modes, so as to determine the mode switching scheduling strategy through at least one transitional operating mode.

[0130] Based on the related descriptions of other embodiments, it can be understood that when the real-time DC bus voltage of the target DC microgrid system deviates significantly from the rated value, the target DC microgrid system will switch the operating mode and tend to be unstable. Therefore, when the real-time DC bus voltage drops to the voltage threshold, the embodiment of the present application can correct the system trajectory of the target DC microgrid system by introducing at least one transitional operating mode, complete a stable mode switch, and prevent the voltage from further dropping while doing so.

[0131] As a possible implementation manner, when controlling the target DC microgrid system to switch the operating mode according to the current operating mode, stability region, and at least one transitional operating mode of the target DC microgrid system, the embodiment of the present application can, but is not limited to, select at least one transitional operating mode from multiple operating modes of the target DC microgrid system or multiple pre-established transitional operating modes or multiple operating modes and multiple pre-established transitional operating modes of the target DC microgrid system.

[0132] Among them, multiple pre-established transitional operating modes can be established by those skilled in the art according to the actual situation and actual needs. The embodiments of the present application only make exemplary descriptions and do not make specific limitations. Also, in order to avoid adding new modes, the transitional operating modes can also be selected from multiple operating modes of the target DC microgrid system. Then, the embodiment of the present application determines the mode switching scheduling strategy through the at least one operating mode, and controls the target DC microgrid system to perform mode switching according to the mode switching scheduling strategy, thereby improving the stability of the system.

[0133] For example, among multiple operating modes and / or multiple pre-established transitional operating modes, there is a transitional operating mode whose stability region can cover the stable equilibrium point of the current operating mode, and the stability region of the target operating mode can cover the stable equilibrium point of this transitional operating mode, then this transitional operating mode can be selected.

[0134] If there is no such transition operation mode in the multiple operation modes and / or the multiple transition operation modes established in advance, or a transition operation mode cannot satisfy the stability of the target DC microgrid system during the switching mode, the embodiment of the present application can select a transition operation mode with a larger stability domain from the multiple operation modes and / or the multiple transition operation modes established in advance to achieve the effect of covering the initial stable equilibrium point as much as possible. Once the bus voltage exceeds the threshold, the target DC microgrid system switches to the transition operation mode with a larger stability domain to adapt to different operating conditions and requirements.

[0135] For example, taking the DC microgrid switching system model (6) as the original switching mode scheduling strategy of the target DC microgrid system (directly switching from the current operating mode to the target operating mode) as an example, by comparing the size of the stable domain of the target DC microgrid system under each operating mode under the same equivalent constant power load, it is found that the stable domain of operating mode 1 is the largest. Therefore, operating mode 1 is selected as the transition operating mode. By introducing this transition operating mode, the system trajectory of the target DC microgrid system can be changed, so that the stable equilibrium point of the current operating mode enters the stable domain of the target operating mode. Under the original switching strategy (6), the positive feedback of a sharp drop in bus voltage may cause system instability. Therefore, when the bus voltage reaches the threshold, operating mode 1 is activated to achieve trajectory adjustment and avoid system instability. The algorithm flow can be expressed as follows:

[0136] (a) Real-time monitoring of bus voltage v bus ;

[0137] (b) If v bus ≤V min , then proceed to step (c); otherwise, the system operates according to the switching strategy (6);

[0138] (c) Switch the system to transition operation mode, i.e., operation mode 1.

[0139] The following is a switching strategy adjusted based on the mode switching dispatching control method of the DC microgrid in the embodiment of the present application:

[0140]

[0141] Figure 3 This is a control block diagram of the operation mode switching of an embodiment of the present application, such as Figure 3 As shown:

[0142] When the equivalent constant power load switches from mode 1 to mode 3, the power steps from -1.2kW to 0.1kW;

[0143] In the case where the equivalent constant-power load switches from mode 2 to mode 4, the power steps from -0.1 kW to 1.2 kW;

[0144] In the case where the equivalent constant-power load switches from mode 3 to mode 4, the power steps from 0.1 kW to 1.3 kW.

[0145] Figure 4 It is a schematic diagram for comparing the simulation results of an embodiment of this application. As Figure 4 shown, Figure 4 it shows the simulation results of the bus voltage v bus under the original switching strategy (6) and the switching mode scheduling strategy (10) of this application. At t = 0.5 s, a step change occurs in the equivalent constant-power load. When the switching mode scheduling strategy (6) is adopted, the target DC microgrid system is unstable, as Figure 3 shown by the blue curve in. Now, change the switching mode scheduling strategy to (10), and the simulation results are as Figure 3 shown by the orange curve in. It can be seen that under the adjusted switching mode scheduling strategy, the target DC microgrid system finally tends to be stable, that is, this application can improve the stability of the target DC microgrid system during mode switching.

[0146] It should be noted that the mode switching scheduling control method of the DC microgrid in this application has more significant engineering application value in deep space exploration mission scenarios (especially for target DC microgrid systems with high reliability requirements such as lunar base). It can also be applied in target DC microgrid systems that are not lunar-oriented. Specifically, it can be selected by professionals in this field according to the actual situation. The embodiments of this application are only for illustrative purposes and are not specifically limited.

[0147] According to the mode switching scheduling control method of the DC microgrid proposed by the embodiments of the present application, the stable equilibrium point and the stable region of the operating mode can be analyzed to determine the influence on the stability of the target DC microgrid system according to the operating mode of the target DC microgrid system, so as to introduce at least one transitional operating mode to control the DC microgrid system to perform mode switching according to the analysis results. Thus, by adjusting the mode switching process of the target DC microgrid system, the system trajectory is changed, the system trajectory is effectively guided into the stable region of the target operating mode, and the positive feedback instability caused by the DC bus voltage drop during the switching process is reduced. Moreover, the implementation of the present application is simple, without any modification to the system hardware structure, and can be achieved only by optimizing the switching strategy and introducing a transitional operating mode, which can make the controller design more concise and efficient, reduce the system complexity, and has good economy and operability; and the present application can monitor the key variables of the DC bus voltage that trigger mode switching in real time, so as to achieve real-time and accurate control of the system operation process and improve the stability and reliability of the DC microgrid. Thus, the problems in the related art that the DC microgrid control method ignores the dynamic coupling effect existing in the mode switching process, cannot cope with the voltage instability caused by mode switching of the DC microgrid, is difficult to achieve lightweight real-time control, and has insufficient adaptability to resource constraints are solved.

[0148] Next, a mode switching scheduling control device for a DC microgrid according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0149] Figure 5 It is a schematic structural diagram of a mode switching scheduling control device for a DC microgrid according to an embodiment of the present application.

[0150] As Figure 5 shown, the mode switching scheduling control device 10 of the DC microgrid includes: a determination module 100, a establishment module 200, and a control module 300.

[0151] Among them, the determination module 100 is used to determine multiple operating modes of the target DC microgrid system based on the target DC microgrid system and its DC bus voltage.

[0152] The establishment module 200 is used to establish a switching system model of the target DC microgrid system based on multiple operating modes of the target DC microgrid system, so as to obtain an analysis result of the mode switching stability of the target DC microgrid system through the switching system model.

[0153] The control module 300 is configured to determine the stability region of the target operating mode of the target DC microgrid system according to the analysis result, and detect the real-time voltage of the target DC microgrid system, so as to determine the mode switching scheduling strategy of the target DC microgrid system based on the current operating mode, stability region and at least one transition operating mode of the target DC microgrid system when the real-time voltage reaches the voltage threshold and the stability region meets the preset conditions, and control the target DC microgrid system to execute the mode switching scheduling strategy.

[0154] Optionally, in an embodiment of the present application, the determination module 100 includes:

[0155] An acquisition unit, configured to acquire the rated DC bus voltage and the operating voltage range of the target DC microgrid system.

[0156] A first determination unit, configured to determine multiple operating modes of the target DC microgrid system according to the rated DC bus voltage and the operating voltage range.

[0157] Optionally, in an embodiment of the present application, the establishment module 200 includes:

[0158] A second determination unit, configured to determine the simplified system corresponding to the target DC microgrid system according to the equivalent characteristics of the power supply and load of the target DC microgrid system.

[0159] A modeling unit, configured to analyze at least one component element of the simplified system to model at least one component element to determine the state equation corresponding to the target DC microgrid system.

[0160] An establishment unit, configured to establish a switching system model corresponding to the target DC microgrid system based on multiple operating modes of the target DC microgrid system and the state equation of the target DC microgrid system.

[0161] Optionally, in an embodiment of the present application, the establishment module 200 includes:

[0162] A calculation unit, configured to calculate the stable equilibrium point and stability region of the target DC microgrid system in multiple operating modes of the target DC microgrid system based on the switching system model.

[0163] An analysis unit, configured to analyze the mode switching stability of the target DC microgrid system according to the stable equilibrium points and stability regions in multiple operating modes to obtain the analysis result.

[0164] Optionally, in an embodiment of the present application, the control module 300 includes:

[0165] A selection unit, configured to select at least one transition operation mode from multiple operation modes and / or multiple pre-established transition operation modes based on the current operation mode and the stability region of the target DC microgrid system, so as to determine a mode switching scheduling strategy through the at least one transition operation mode.

[0166] Optionally, in an embodiment of the present application, the expression of the switching system model can be but is not limited to being expressed as:

[0167] x = f σ (x), σ = {1, 2, 3, 4},

[0168]

[0169] where x is the slow state variable of the second-order reduced-order model of the state equation, and f σ : σ ∈ S is a set of continuous functions representing the dynamic equations of each mode; S = {1, 2,..., 4} is an index set used to characterize the discrete state of the system; σ: [0, ∞) → S is a piecewise constant function whose value is in the set S, representing the switching signal of the system; [V1, V4] is the voltage range for the normal operation of the DC microgrid, and v bus is the DC bus voltage.

[0170] It should be noted that the foregoing explanation of the embodiment of the mode switching scheduling control method for the DC microgrid also applies to the mode switching scheduling control device of the DC microgrid in this embodiment, and will not be elaborated here.

[0171] The mode switching scheduling control device of the DC microgrid proposed according to the embodiments of the present application can analyze the influence of the stable equilibrium point and stable region of the operating mode on the stability of the target DC microgrid system according to the operating mode of the target DC microgrid system, so as to introduce at least one transitional operating mode according to the analysis result to control the DC microgrid system to perform mode switching. Thus, by adjusting the mode switching process of the target DC microgrid system, the system trajectory is changed, the system trajectory is effectively guided into the stable region of the target operating mode, and the positive feedback instability caused by the DC bus voltage drop during the switching process is reduced. Moreover, the implementation of the present application is simple, without any modification to the system hardware structure, and can be achieved only by optimizing the switching strategy and introducing the transitional operating mode, which can make the controller design more concise and efficient, reduce the system complexity, and has good economy and operability; and the present application can monitor the key variables of the DC bus voltage that trigger the mode switching in real time, so as to realize the real-time and accurate control of the system operation process, and improve the stability and reliability of the DC microgrid. Thus, the problems in the related DC microgrid control methods are solved, such as ignoring the dynamic coupling effect existing in the mode switching process, being unable to cope with the voltage instability caused by the mode switching of the DC microgrid, being difficult to achieve lightweight real-time control, and insufficient adaptability to resource constraints.

[0172] Figure 6 The structural schematic diagram of the electronic device provided by the embodiments of the present application. The electronic device may include:

[0173] A memory 601, a processor 602, and a computer program stored on the memory 601 and executable on the processor 602.

[0174] When the processor 602 executes the program, it implements the mode switching scheduling control method of the DC microgrid provided in the above embodiments.

[0175] Furthermore, the electronic device further includes:

[0176] A communication interface 603 for communication between the memory 601 and the processor 602.

[0177] The memory 601 is used to store the computer program that can be run on the processor 602.

[0178] The memory 601 may include a high-speed RAM memory, and may also include a non-volatile memory, such as at least one disk memory.

[0179] If the memory 601, the processor 602, and the communication interface 603 are implemented independently, the communication interface 603, the memory 601, and the processor 602 can be interconnected through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6 only a thick line is used to represent it in Figure 6 , but it does not mean that there is only one bus or one type of bus.

[0180] Optionally, in a specific implementation, if the memory 601, the processor 602, and the communication interface 603 are integrated on a single chip, the memory 601, the processor 602, and the communication interface 603 can communicate with each other through an internal interface.

[0181] The processor 602 may be a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0182] The embodiments of the present application further provide a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the above-mentioned mode switching scheduling control method of the DC microgrid is implemented.

[0183] The embodiments of the present application further provide a computer program product, including a computer program, which can run computer instructions. When the computer instructions are executed by a processor, the mode switching scheduling control method of the DC microgrid provided by the embodiments of the present application is implemented.

[0184] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0185] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "N" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0186] Any process or method description shown in the flowchart or described in other ways herein may be understood to represent a module, segment, or portion of code including one or N executable instructions for implementing a customized logic function or process, and the scope of the preferred embodiments of this application includes additional implementations, where the functions may be executed in a substantially simultaneous manner or in a reverse order according to the functions involved, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of this application belong.

[0187] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a definable sequence list of executable instructions for implementing logical functions, which can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or used in combination with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion (electronic device) having one or N wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically by optically scanning the paper or other media, followed by editing, interpretation, or otherwise processing as appropriate, and then stored in a computer memory.

[0188] It should be understood that various parts of the present application can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented by a combination of any one or more of the following techniques well known in the art: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0189] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried by the method of the above embodiments can be completed by a program instructing relevant hardware, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0190] In addition, each functional unit in various embodiments of the present application may be integrated into one processing module, or each unit may exist physically alone, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0191] The above-mentioned storage medium may be a read-only memory, a magnetic disk, an optical disc, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A mode switching dispatching control method for a DC microgrid, characterized in that: The following steps are involved: Based on the target DC microgrid system and its DC bus voltage, determining multiple operation modes of the target DC microgrid system; Based on the multiple operation modes of the target DC microgrid system, a switching system model corresponding to the target DC microgrid system is established, so as to obtain an analysis result of the mode switching stability of the target DC microgrid system through the switching system model; The stable domain of the target operation mode of the target DC microgrid system is determined according to the analysis result, and the real-time voltage of the target DC microgrid system is detected, so that when the real-time voltage reaches a voltage threshold and the stable domain satisfies a preset condition, based on the current operation mode of the target DC microgrid system, the stable domain and at least one transition operation mode, a mode switching scheduling strategy of the target DC microgrid system is determined, and the target DC microgrid system is controlled to execute the mode switching scheduling strategy.

2. The method according to claim 1, characterized in that Determining the multiple operation modes of the target DC microgrid system according to the target DC microgrid system and its DC bus voltage includes: Obtaining a rated DC bus voltage and an operating voltage range of the target DC microgrid system; Multiple operating modes of the target DC microgrid system are determined according to the rated DC bus voltage and the operating voltage range.

3. The method according to claim 1, characterized in that The step of establishing a switching system model corresponding to the target DC microgrid system based on the multiple operation modes of the target DC microgrid system includes: Determining a simplified system corresponding to the target DC microgrid system according to equivalent characteristics of a power source and a load of the target DC microgrid system; Analyzing at least one component of the simplified system to model the at least one component to determine a state equation corresponding to the target DC microgrid system; Based on the multiple operation modes of the target DC microgrid system and the state equation corresponding to the target DC microgrid system, a switching system model corresponding to the target DC microgrid system is established.

4. The method according to claim 1, characterized in that The analysis result of the mode switching stability of the target DC microgrid system obtained by the switching system model includes: Based on the switching system model, calculating the stable equilibrium point and the stable domain of the target DC microgrid system under multiple operation modes of the target DC microgrid system; The mode switching stability of the target DC microgrid system is analyzed according to the stable equilibrium points and stable domains under the multiple operating modes to obtain the analysis result.

5. The method according to claim 1, characterized in that The determining of the mode switching scheduling strategy of the target DC microgrid system based on the current operation mode of the target DC microgrid system, the stable domain and at least one transition operation mode includes: Based on the current operation mode of the target DC microgrid system and the stability domain, at least one transition operation mode is selected from multiple operation modes of the target DC microgrid system and / or multiple pre-established transition operation modes, so as to determine the mode switching scheduling strategy through the at least one transition operation mode.

6. The method according to claim 1, characterized in that The expression of the switching system model is: x=f σ (x),σ={1,2,3,4}, Where x is the slow state variable of the second-order reduced-order model of the state equation, f σ :σ∈S is a set of continuous functions, representing the dynamic equations of each mode; S={1,2,…,4} is an index set used to characterize the discrete state of the system; σ:[0,∞)→S is a piecewise constant function whose value is in the set S, representing the switching signal of the system; [V1,V4] is the voltage range of the normal operation of the DC microgrid, v bus is the DC bus voltage, V N is the voltage rating.

7. A mode switching dispatching control device for a DC microgrid, characterized in that: include: A determination module, configured to determine multiple operation modes of the target DC microgrid system based on the target DC microgrid system and its DC bus voltage; An establishing module is used to establish a switching system model corresponding to the target DC microgrid system based on multiple operating modes of the target DC microgrid system, so as to obtain an analysis result of the mode switching stability of the target DC microgrid system through the switching system model; A control module is used to determine the stability domain of the target operation mode of the target DC microgrid system according to the analysis result, and detect the real-time voltage of the target DC microgrid system, so as to determine the mode switching scheduling strategy of the target DC microgrid system based on the current operation mode of the target DC microgrid system, the stability domain and at least one transition operation mode when the real-time voltage reaches a voltage threshold and the stability domain satisfies a preset condition, and control the target DC microgrid system to execute the mode switching scheduling strategy.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the mode switching dispatching control method for a DC microgrid as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the mode switching scheduling control method of a DC microgrid as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed, it is used to implement the mode switching scheduling control method of the DC microgrid as described in any one of claims 1 to 6.

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