Information physical fusion modeling method and system for off-grid micro-grid containing distributed source storage

Abstract

The invention discloses an off-grid micro-grid information physical fusion modeling method and system containing distributed source storage. The method comprises the following steps: constructing a physical model for the micro-grid according to the physical characteristics of the micro-grid, and describing the basic logic of the operation of the micro-grid; representing information characteristics of the micro-grid by using a finite-state machine, and establishing a micro-grid information basic model; according to operation characteristics and control strategies of different devices in the micro-grid, information physical models of a micro-grid source storage unit are established respectively; based on a hybrid logic dynamic method, events such as control state change of each distributed source storage of the micro-grid and information physical fusion are considered, and a micro-grid information physical model is established. According to the method, information modeling is carried out on the micro-grid based on the principle of a finite-state machine, information physical model association is carried out through a hybrid logic dynamic method, a switching control method is adopted for a fan unit, a photovoltaic unit and an energy storage unit, and the energy utilization rate and power of the system are improved while safe and stable operation of all the units is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of microgrid information-physical fusion, and in particular relates to an off-grid microgrid information-physical fusion modeling method and system containing distributed source storage. Background Art

[0002] The electric energy structure is shifting towards a high proportion of distributed access to new energy. However, the large-scale access to renewable energy such as wind power and photovoltaics has had a significant impact on the structure and operation mode of the power system. Microgrid is an emerging research topic in the field of power systems today. The microgrid system is a typical cyber physical system (CPS) because it integrates computing, communication and network technologies (information part) with physical devices (physical part). However, the existing microgrid system modeling analysis or control mainly starts from the perspective of physical system operation control, and lacks a description of the relationship between the information flow and energy flow of the microgrid system. For a typical off-grid microgrid with source storage, since it does not operate in parallel with the large power grid, it cannot obtain external reference instructions in real time and relies more on the communication between its internal components. Therefore, its cyber-physical coupling modeling is also more important. Summary of the invention

[0003] Purpose of the invention: In view of the shortcomings of the prior art, the purpose of the present invention is to provide an information-physical fusion modeling method and system for an off-grid microgrid containing distributed sources and storage, which adds modeling of information characteristics to the traditional microgrid physical model to achieve the association and coupling of information flow and energy flow.

[0004] Technical solution: A method for information-physical fusion modeling of an off-grid microgrid with distributed source and storage, comprising the following steps:

[0005] A physical model of the microgrid is constructed according to the physical characteristics of the microgrid to describe the basic logic of the operation of the microgrid. The distributed source and storage of the microgrid include a wind turbine unit, a photovoltaic unit, and an energy storage unit. The physical model represents the continuous operation law of the wind turbine unit, the photovoltaic unit, and the energy storage unit.

[0006] The information characteristics of each unit of the microgrid are represented by the finite state machine, and the basic information model of each unit equipment of the microgrid is established;

[0007] According to the physical model and the information basic model, based on the operating characteristics and control strategies of different devices in the microgrid, the information physical models of the source storage units of the microgrid are respectively established;

[0008] Based on the information-physical model of the microgrid source-storage unit, a hybrid logic dynamic method is used to consider the control state change events of each distributed source-storage unit in the microgrid and information-physical fusion to establish a microgrid information-physical model.

[0009] Furthermore, the information characteristics of each unit of the microgrid are represented by a finite state machine, and the information basic model of each unit device of the microgrid is established, including:

[0010] The finite state machine tool is used to represent the state of each unit device in the microgrid, and the driving events of each state transition are listed. When different events occur, the finite state machine will drive each unit device to transfer and transform the state and display it, thus obtaining the information basic model of each unit device in the microgrid;

[0011] Among them, the trajectory of each unit device starts from the initial state (s1, x1), and the conversion process includes the evolution of the continuous state and the switching of the operating state. When the initial operating state is s1, the continuous variable x evolves according to the following differential equation:

[0012]

[0013] Where f represents the continuous dynamic change relationship function of the controlled object at this time, and x(0) represents the x value at time 0.

[0014] Further, according to the physical model and the information basic model, based on the operating characteristics and control strategies of different devices in the microgrid, information physical models of the source storage unit of the microgrid are established respectively, including:

[0015] Based on the switching control concept, for wind power units, the operating state is determined by the wind speed; for photovoltaic units, the operating state is determined by the constant power reference value;

[0016] For energy storage units, the operating states are divided according to their state of charge.

[0017] Furthermore, the photovoltaic unit is divided into two operating states: fixed power output state and maximum output power state. The dividing point between the two states is the fixed power reference value P ref , by comparing the constant power reference value P of the photovoltaic unit ref and the maximum output power P max Determine which operating state it is working in. The operating characteristics of the photovoltaic unit are expressed as:

[0018]

[0019] Furthermore, the fan unit is divided into two operating states: when the wind speed v is greater than the cut-in wind speed v in Less than rated wind speed v nThe wind turbine will run in the maximum power tracking mode when the wind speed v is less than the cut-in wind speed v in When or above the rated wind speed v n When the fan is turned off, it will run in shutdown mode, and the output characteristic of the fan can be described as follows:

[0020]

[0021] Furthermore, for the energy storage unit, when the state of charge of the energy storage unit is lower than the minimum allowable value SOC min When the state of charge is greater than the maximum allowable value SOC max When the state of charge is between the maximum allowable value and the minimum allowable value, the energy storage unit will choose to operate in charging mode or discharging mode according to system requirements. The operating characteristics of the energy storage unit are as follows:

[0022]

[0023] Where: SOC(t) and SOC(t-1) represent the state of charge of the energy storage unit at time t and t-1 respectively; Bat c Represents the capacity of the energy storage unit; η COV Represents the conversion efficiency of the converter; η ch and η dch Respectively represent the charging and discharging efficiency of BSS; P input (t) represents the sum of the power input to the BSS at this moment. If the input power of the energy storage unit is greater than the load demand, that is, P input (t)>P load (t), the load is supplied first, and the remaining power is used to charge the energy storage unit; if P input (t)≤P load (t), the generated power will be used to supply the load, and the insufficient power will be provided by the energy storage unit.

[0024] Furthermore, a hybrid logic dynamic method is used to consider the control state change events of each distributed source and storage in the microgrid and the information-physical fusion, and a microgrid information-physical model is established, including:

[0025] The state of the microgrid system includes the state set of its unit devices, and the state of the microgrid system is defined as follows:

[0026] S=(e1,e2,e3,......,e n )

[0027] Among them, S represents the system state; e iIndicates the status of each unit device in the system, i = 1, 2, 3...; n is the number of system devices; whenever the external environment or system instructions change, the corresponding components undergo state transfer due to the corresponding event drive, and the entire system state changes; the system state is included in the finite set, and whenever the state is converted, the finite state machine tool can display various related indicators and event states;

[0028] Based on the information-physical models of the source and storage units, the hybrid logic dynamic method is used to design the logic variables and convert the logic information in the microgrid into equation form. The hybrid logic dynamic model of the microgrid is as follows:

[0029] x(t+1)=A i x(t)+B u u(t)+B 2t δ(t)+B 3t z(t)

[0030] y(t)=C i x(t)+D u u(t)+D 2t δ(t)+D 3t z(t)

[0031] E 2t δ(t)+E 3t z(t)≤E 4t x(t)+E 1t u(t)+E 5t

[0032] In the formula, x(t), u(t), y(t) are the continuous variable, control variable and output variable of the controlled object respectively; δ(t) is the logical variable; z(t) is the auxiliary variable; E nt is the state transition mapping; A, B, C, D are the coefficients of the corresponding variables;

[0033] The microgrid hybrid logic dynamic model is used as the microgrid information physical model.

[0034] An off-grid microgrid information-physical fusion modeling system with distributed source and storage, comprising:

[0035] A physical model building module is used to build a physical model of the microgrid according to the physical characteristics of the microgrid, and describe the basic logic of the operation of the microgrid. The distributed source and storage of the microgrid include a wind turbine unit, a photovoltaic unit, and an energy storage unit. The physical model represents the continuous operation law of the wind turbine unit, the photovoltaic unit, and the energy storage unit.

[0036] An information model building module is used to use a finite state machine to represent the information characteristics of each unit of the microgrid and establish an information basic model of each unit device of the microgrid;

[0037] The information-physical model construction module is used to establish the information-physical models of the microgrid source-storage units according to the physical model and the information basic model, based on the operating characteristics and control strategies of different devices in the microgrid; and based on the information-physical model of the microgrid source-storage units, a hybrid logic dynamic method is used to consider the control state change events of each distributed source and storage of the microgrid and information-physical fusion to establish the microgrid information-physical model.

[0038] Furthermore, the information characteristics of each unit of the microgrid are represented by a finite state machine, and the information basic model of each unit device of the microgrid is established, including:

[0039] The finite state machine tool is used to represent the state of each unit device in the microgrid, and the driving events of each state transition are listed. When different events occur, the finite state machine will drive each component to transfer and transform the state and display it, thus obtaining the information basic model of each unit device in the microgrid;

[0040] Among them, the trajectory of each unit device starts from the initial state (s1, x1), and the conversion process includes the evolution of the continuous state and the switching of the operating state. When the initial operating state is s1, the continuous variable x evolves according to the following differential equation:

[0041]

[0042] Where f represents the continuous dynamic change relationship function of the controlled object at this time, and x(0) represents the x value at time 0.

[0043] Further, according to the physical model and the information basic model, based on the operating characteristics and control strategies of different devices in the microgrid, information physical models of the source storage unit of the microgrid are established respectively, including:

[0044] Based on the switching control concept, for wind power units, the operating state is determined by the wind speed; for photovoltaic units, the operating state is determined by the constant power reference value;

[0045] For energy storage units, the operating states are divided according to their state of charge.

[0046] Furthermore, the photovoltaic unit is divided into two operating states: fixed power output state and maximum output power state. The dividing point between the two states is the fixed power reference value P ref , by comparing the constant power reference value P of the photovoltaic unit ref and the maximum output power P max Determine which operating state it is working in. The operating characteristics of the photovoltaic unit are expressed as:

[0047]

[0048] Furthermore, the fan unit is divided into two operating states: when the wind speed v is greater than the cut-in wind speed v in Less than rated wind speed v n The wind turbine will run in the maximum power tracking mode when the wind speed v is less than the cut-in wind speed v in When or above the rated wind speed v n When the fan is turned off, it will run in shutdown mode, and the output characteristic of the fan can be described as follows:

[0049]

[0050] Furthermore, for the energy storage unit, when the state of charge of the energy storage unit is lower than the minimum allowable value SOC min When the state of charge is greater than the maximum allowable value SOC max When the state of charge is between the maximum allowable value and the minimum allowable value, the energy storage unit will choose to operate in charging mode or discharging mode according to system requirements. The operating characteristics of the energy storage unit are as follows:

[0051]

[0052] Where: SOC(t) and SOC(t-1) represent the state of charge of the energy storage unit at time t and t-1 respectively; Bat c Represents the capacity of the energy storage unit; η COV Represents the conversion efficiency of the converter; η ch and η dch Respectively represent the charging and discharging efficiency of BSS; P input (t) represents the sum of the power input to the BSS at this moment. If the input power of the energy storage unit is greater than the load demand, that is, P input (t)>P load (t), the load is supplied first, and the remaining power is used to charge the energy storage unit; if P input (t)≤P load (t), the generated power will be used to supply the load, and the insufficient power will be provided by the energy storage unit.

[0053] Furthermore, a hybrid logic dynamic method is used to consider the control state change events of each distributed source and storage in the microgrid and the information-physical fusion, and a microgrid information-physical model is established, including:

[0054] The state of the microgrid system includes the state set of its unit devices, and the state of the microgrid system is defined as follows:

[0055] S=(e1,e2,e3,......,en )

[0056] Among them, S represents the system state; e i Indicates the status of each unit device in the system, i = 1, 2, 3...; n is the number of system devices; whenever the external environment or system instructions change, the corresponding components undergo state transfer due to the corresponding event drive, and the entire system state changes; the system state is included in the finite set, and whenever the state is converted, the finite state machine tool can display various related indicators and event states;

[0057] Based on the information-physical models of the source and storage units, the hybrid logic dynamic method is used to design the logic variables and convert the logic information in the microgrid into equation form. The hybrid logic dynamic model of the microgrid is as follows:

[0058] x(t+1)=A i x(t)+B u u(t)+B 2t δ(t)+B 3t z(t)

[0059] y(t)=C i x(t)+D u u(t)+D 2t δ(t)+D 3t z(t)

[0060] E 2t δ(t)+E 3t z(t)≤E 4t x(t)+E 1t u(t)+E 5t

[0061] In the formula, x(t), u(t), y(t) are the continuous variable, control variable and output variable of the controlled object respectively; δ(t) is the logical variable; z(t) is the auxiliary variable; E nt is the state transition mapping; A, B, C, D are the coefficients of the corresponding variables;

[0062] The microgrid hybrid logic dynamic model is used as the microgrid information physical model.

[0063] The present invention also provides a computer device, comprising: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and when the programs are executed by the processors, the steps of the information-physical fusion modeling method for an off-grid microgrid containing distributed sources and storage are implemented as described above.

[0064] The present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the information-physical fusion modeling method for an off-grid microgrid containing distributed sources and storage are implemented as described above.

[0065] Beneficial effects: The present invention first establishes a traditional physical model of the microgrid based on the physical characteristics of the microgrid, wherein interfaces are set aside for subsequent information models for source storage and other equipment, and information-physical model association is performed. Based on the principle of finite state machines, existing finite state machine tools can be used to perform information modeling on microgrids, and information-physical model association is performed through a hybrid logic dynamic method. For wind turbines, photovoltaics, and energy storage units, a switching control method is used to ensure the safe and stable operation of each unit while improving the energy utilization and power of the system, and facilitating the observation of system state transitions. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 The flowchart of the information-physical fusion modeling method for off-grid microgrids with distributed sources and storage;

[0067] Figure 2 It is a schematic diagram of the physical topology of the microgrid;

[0068] Figure 3 Schematic diagram of the hierarchical architecture of a microgrid. DETAILED DESCRIPTION

[0069] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings.

[0070] In order to fully demonstrate the relationship between the information flow and energy flow of the microgrid system and clearly present the operating status and change process of each unit in the microgrid, it is necessary to integrate the information system and physical system of the microgrid system into a whole for modeling and analysis. The present invention proposes an off-grid microgrid information-physical fusion modeling method with distributed source storage. Figure 1 As shown, the method comprises the following steps:

[0071] Step 1: Construct a physical model of the microgrid based on its physical characteristics and describe the basic logic of the microgrid operation.

[0072] The main equipment of the microgrid includes: wind turbine unit, photovoltaic unit, energy storage unit and flexible load unit. The physical topology of the microgrid is as follows: Figure 2. Since information modeling is generally not performed separately for the load, the present invention does not model the load either. The focus of the present invention is to consider the fusion modeling of the source and storage parts. The energy storage unit includes: a battery unit, a hydrogen fuel cell unit and a supercapacitor unit. The wind turbine unit converts wind energy into electrical energy, and the output power is affected by the wind speed. The photovoltaic unit converts solar energy into electrical energy, and the output power is affected by the light intensity and temperature. The battery unit stores or releases electrical energy and has a charge and discharge cycle characteristic. The hydrogen fuel cell unit generates electrical energy through the reaction of hydrogen and oxygen, and produces water at the same time. The supercapacitor unit provides fast charging and discharging capabilities, which is suitable for power fluctuation regulation.

[0073] The physical model mainly describes the physical characteristics (i.e., the continuous operation rules) in the microgrid. At the level of the physical model, each unit of the system passes information related to its own state and perceived environmental information to the subsequently established information model, and executes the control instructions issued by the control layer. Due to the combination with the information model, it presents a hybrid system feature during operation. After modeling the physical layer, interfaces need to be reserved for the corresponding information elements to facilitate communication between the elements. The hierarchical architecture of the microgrid is as follows: Figure 3 As shown in the figure, the physical device layer establishes the physical model of the microgrid; the control decision layer establishes the power control module; the system optimization layer is mainly the source of external events, driving the system to operate or perform state transitions.

[0074] The response of physical devices in a microgrid to external commands and the events generated by their internal states are discrete processes. The output of the device (such as voltage and current) changes continuously over time according to a certain rule, which is a continuous process. Generally speaking, physical characteristics include:

[0075] Dynamic characteristics: including output power, efficiency, life cycle, etc. of various energy units.

[0076] Static characteristics: including equipment capacity, rated voltage, current and other parameters.

[0077] Connection method: Determine the connection topology between each unit, such as series-parallel connection.

[0078] Operation logic: describes the startup, operation, and shutdown processes of the microgrid, as well as the direction and regulation mechanism of energy flow.

[0079] According to the physical characteristics of the microgrid, simulation software (such as simulink) is used to establish corresponding equipment components, and each component is connected according to the corresponding connection method.

[0080] Step 2: Use finite state machine to represent the information characteristics of microgrid and establish the basic information model of microgrid.

[0081] The present invention is based on a finite state machine to represent the information characteristics of a microgrid. The microgrid contains countable states. When a corresponding state event occurs, the microgrid will transfer from the current state to the corresponding state, which can be achieved through a finite state machine. There are certain conditions for realizing state transfer in a finite state machine, and states that are converted to each other will have state transfer events. In this model, events from the physical layer or the information layer will drive the microgrid to transfer to different states. This hierarchical model can clearly reflect the conversion information between the various states of the microgrid and the operating characteristics of the microgrid itself, and is used as the basis of the information model.

[0082] The state of the microgrid is formed by combining the states of each component in the microgrid. For example, if the wind turbine is in state 1, the photovoltaic is in state 3, and the energy storage is in state 5, then the state of the microgrid is (wind turbine state 1, photovoltaic state 3, energy storage state 5).

[0083] The information characteristic of the microgrid is its discrete part. The trajectory of the device starts from the initial state (s1, x1), and the conversion process includes the evolution of the continuous state and the switching of the operating state. When the initial operating state is s1, the continuous variable x will evolve according to the following differential equation. The information characteristic can be expressed as follows:

[0084]

[0085] Where f represents the continuous dynamic change relationship function of the controlled object at this time, and x(0) represents the x value at time 0.

[0086] The present invention uses the finite state machine tool stateflow to represent the state of each component in the microgrid and lists the driving events of each state transition. The system will drive each component to transfer the state according to the occurrence of different events and display it clearly.

[0087] Based on the switching control concept, considering the operating characteristics of wind turbines, the control strategy of the wind turbine unit will change when the system state changes. For wind turbines, the operating state is determined by the wind speed. Similarly, considering the operating characteristics of photovoltaic units, the photovoltaic system adopts the same switching control method. For photovoltaic units, the operating state is determined by the fixed power reference value. For energy storage units, the operating state is divided according to their charge state.

[0088] Step 3: According to the operating characteristics and control strategies of different devices in the microgrid, the cyber-physical models of the microgrid source and storage components are established respectively.

[0089] The photovoltaic unit can be divided into two operating states: fixed power output state and maximum output power state. The dividing point between the two states is the fixed power reference value P. ref , by comparing the constant power reference value P of the photovoltaic unitref and the maximum output power P max It can be determined which operating state it is working in. The operating characteristics of the photovoltaic unit are expressed as:

[0090]

[0091] The fan unit can be divided into two operating states: when the wind speed v is greater than the cut-in wind speed v in Less than rated wind speed v n When the wind speed v is less than the cut-in wind speed v in When or above the rated wind speed v n When the fan is running in shutdown mode, the fan output characteristic can be described as follows:

[0092]

[0093] For energy storage units, an important indicator is its state of charge (SOC). When SOC takes different values, it can be judged what state the energy storage unit is in. When the state of charge of the energy storage unit is lower than the minimum allowable value SOC min When the state of charge is greater than the maximum allowable value SOC max When the state of charge is between the maximum allowable value and the minimum allowable value, the energy storage unit can choose to operate in charging mode or discharging mode according to system requirements. Therefore, the energy storage unit can be divided into four operating states: charging, discharging, idle and shutdown. The operating characteristics of the energy storage unit are shown as follows:

[0094]

[0095] Where: SOC(t) and SOC(t-1) represent the state of charge of the energy storage unit at time t and t-1 respectively; Bat c Represents the capacity of the energy storage unit; η COV Represents the conversion efficiency of the converter; η ch and η dch Respectively represent the charging and discharging efficiency of the energy storage unit; P input (t) represents the sum of the power input to the energy storage unit at this moment. If the input power of the energy storage unit is greater than the load demand, that is, P input (t)>P load (t), the load is supplied first, and the remaining power is used to charge the energy storage unit. input (t)≤P load (t), the generated power will be used to supply the load, and the insufficient power will be provided by the energy storage unit.

[0096] Step 4: Based on the hybrid logic dynamic method, the microgrid cyber-physical model is established by considering events such as the control state changes of each distributed source and storage in the microgrid and cyber-physical fusion.

[0097] The state of a microgrid system includes the state of each of its components. Define the state of a microgrid system:

[0098] S=(e1,e2,e3,......,e n )

[0099] Among them, S represents the system state; e i (i=1,2,3...) represents the state of each component of the system (wind turbine, photovoltaic, energy storage); n is the number of system components. Whenever the external environment or system instructions change, the corresponding components will change their states due to the corresponding event drive, and the state of the entire system will change at this time. The state of the system is included in the finite set. Whenever the state changes, the finite state machine tool will help the operator clearly observe the relevant indicators and event states.

[0100] After using the finite state machine tool stateflow to establish the information-physical model of the microgrid load and storage, the present invention conducts the overall information-physical modeling of the microgrid based on the hybrid logic dynamic method and taking into account the control state changes of each distributed source and storage of the microgrid and the information-physical fusion. Here, the logical variable δ(t) is designed to convert the logical information in the microgrid into the form of an equation. The hybrid logic dynamic model of the microgrid is as follows:

[0101] x(t+1)=A i x(t)+B u u(t)+B 2t δ(t)+B 3t z(t)

[0102] y(t)=C i x(t)+D u u(t)+D 2t δ(t)+D 3t z(t)

[0103] E 2t δ(t)+E 3t z(t)≤E 4t x(t)+E 1t u(t)+E 5t

[0104] In the formula, x(t), u(t), y(t) are the continuous variable, control variable and output variable of the controlled object respectively; δ(t) is the logical variable; z(t) is the auxiliary variable; E ntis the state transition mapping. A, B, C, D, etc. are the coefficients of the corresponding variables. For each controlled object (wind turbine, photovoltaic, energy storage), there are corresponding continuous variables such as current, voltage, power, etc., and each continuous variable has corresponding control variables and output variables. The established hybrid logic dynamic model combines discrete and continuous variables, and more clearly describes the overall information-physical model of the microgrid.

[0105] When certain events occur, the state of the component changes, triggering the system to switch from one operating state in a finite set to another operating state. The event can come from either the physical model or the information model. When an instruction is received or the external environment changes, it is possible to trigger the transition of the system state. Due to the existence of the finite state machine tool, the transition conditions of the system state and the specific time nodes and states of the transition can be clearly observed.

[0106] According to the modeling method of the present invention, finite state machine tools are installed in the wind turbine, photovoltaic, and energy storage unit respectively to monitor the system status in real time. When an event occurs, the finite state machine will convert the system from the current state to another state and record the time node. Taking the change of the external environment of the system as an example, it is assumed that the wind turbine is in the maximum power tracking state, the photovoltaic is in the constant power mode, and the energy storage unit is in the charging state before the change. When the wind speed of the environment decreases to below the cut-in wind speed and the light intensity is greatly reduced, the system will be converted to the next state, that is, the wind turbine is shut down, the photovoltaic unit is in the maximum power operation mode, and the energy storage unit will be in the discharge mode. The finite state machine tool will record the time node at this time and clearly display the conversion of the system state.

[0107] The present invention also provides an off-grid microgrid information-physical fusion modeling system containing distributed source and storage, comprising:

[0108] A physical model building module is used to build a physical model of the microgrid according to the physical characteristics of the microgrid, and describe the basic logic of the operation of the microgrid. The distributed source and storage of the microgrid include a wind turbine unit, a photovoltaic unit, and an energy storage unit. The physical model represents the continuous operation law of the wind turbine unit, the photovoltaic unit, and the energy storage unit.

[0109] An information model building module is used to use a finite state machine to represent the information characteristics of each unit of the microgrid and establish an information basic model of each unit device of the microgrid;

[0110] The information-physical model construction module is used to establish the information-physical models of the microgrid source-storage units according to the physical model and the information basic model, based on the operating characteristics and control strategies of different devices in the microgrid; and based on the information-physical model of the microgrid source-storage units, a hybrid logic dynamic method is used to consider the control state change events of each distributed source and storage of the microgrid and information-physical fusion to establish the microgrid information-physical model.

[0111] Furthermore, the information characteristics of each unit of the microgrid are represented by a finite state machine, and the information basic model of each unit of the microgrid is established, including:

[0112] The finite state machine tool is used to represent the state of each component in the microgrid, and the driving events of each state transition are listed. When different events occur, the finite state machine will drive each component to transfer and transform the state and display it, thus obtaining the information basic model of each unit device in the microgrid;

[0113] The trajectory of the device starts from the initial state (s1, x1). The conversion process includes the evolution of the continuous state and the switching of the operating state. When the initial operating state is s1, the continuous variable x evolves according to the following differential equation:

[0114]

[0115] Where f represents the continuous dynamic change relationship function of the controlled object at this time, and x(0) represents the x value at time 0.

[0116] Furthermore, based on the operating characteristics and control strategies of different devices in the microgrid, the cyber-physical models of the source and storage units of the microgrid are established respectively, including:

[0117] Based on the switching control concept, for wind power units, the operating state is determined by the wind speed; for photovoltaic units, the operating state is determined by the constant power reference value;

[0118] For energy storage units, the operating states are divided according to their state of charge.

[0119] Furthermore, the photovoltaic unit is divided into two operating states: fixed power output state and maximum output power state. The dividing point between the two states is the fixed power reference value P ref , by comparing the constant power reference value P of the photovoltaic unit ref and the maximum output power P max Determine which operating state it is working in. The operating characteristics of the photovoltaic unit are expressed as:

[0120]

[0121] Furthermore, the fan unit is divided into two operating states: when the wind speed v is greater than the cut-in wind speed vin Less than rated wind speed v n The wind turbine will run in the maximum power tracking mode when the wind speed v is less than the cut-in wind speed v in When or above the rated wind speed v n When the fan is turned off, it will run in shutdown mode, and the output characteristic of the fan can be described as follows:

[0122]

[0123] Furthermore, for the energy storage unit, when the state of charge of the energy storage unit is lower than the minimum allowable value SOC min When the state of charge is greater than the maximum allowable value SOC max When the state of charge is between the maximum allowable value and the minimum allowable value, the energy storage unit will choose to operate in charging mode or discharging mode according to system requirements. The operating characteristics of the energy storage unit are as follows:

[0124]

[0125] Where: SOC(t) and SOC(t-1) represent the state of charge of the energy storage unit at time t and t-1 respectively; Bat c Represents the capacity of the energy storage unit; η COV Represents the conversion efficiency of the converter; η ch and η dch Respectively represent the charging and discharging efficiency of BSS; P input (t) represents the sum of the power input to the BSS at this moment. If the input power of the energy storage unit is greater than the load demand, that is, P input (t)>P load (t), the load is supplied first, and the remaining power is used to charge the energy storage unit; if P input (t)≤P load (t), the generated power will be used to supply the load, and the insufficient power will be provided by the energy storage unit.

[0126] Furthermore, a hybrid logic dynamic method is used to consider the control state change events of each distributed source and storage in the microgrid and the information-physical fusion, and a microgrid information-physical model is established, including:

[0127] The state of the microgrid system includes the state set of its various components, which defines the state of the microgrid system:

[0128] S=(e1,e2,e3,......,e n )

[0129] Among them, S represents the system state; e iIndicates the state of each component of the system, i = 1, 2, 3...; n is the number of system components; whenever the external environment or system instructions change, the corresponding component changes state due to the corresponding event drive, and the state of the entire system changes; the state of the system is included in the finite set, and whenever the state changes, the finite state machine tool can display various related indicators and event states;

[0130] Based on the information-physical models of the source and storage components, the hybrid logic dynamic method is used to design the logic variables and convert the logic information in the microgrid into equation form. The hybrid logic dynamic model of the microgrid is as follows:

[0131] x(t+1)=A i x(t)+B u u(t)+B 2t δ(t)+B 3t z(t)

[0132] y(t)=C i x(t)+D u u(t)+D 2t δ(t)+D 3t z(t)

[0133] E 2t δ(t)+E 3t z(t)≤E 4t x(t)+E 1t u(t)+E 5t

[0134] In the formula, x(t), u(t), y(t) are the continuous variable, control variable and output variable of the controlled object respectively; δ(t) is the logical variable; z(t) is the auxiliary variable; E nt is the state transition mapping; A, B, C, D are the coefficients of the corresponding variables;

[0135] The microgrid hybrid logic dynamic model is used as the microgrid information physical model.

[0136] It should be understood that the off-grid microgrid information-physical fusion modeling system containing distributed sources and storage in the embodiment of the present invention can implement all the technical solutions in the above-mentioned method embodiment, and the functions of its various functional modules can be specifically implemented according to the methods in the above-mentioned method embodiments. The specific implementation process can refer to the relevant description in the above-mentioned embodiments, which will not be repeated here.

[0137] The present invention also provides a computer device, comprising: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and when the programs are executed by the processors, the steps of the information-physical fusion modeling method for an off-grid microgrid containing distributed sources and storage are implemented as described above.

[0138] The present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the information-physical fusion modeling method for an off-grid microgrid containing distributed sources and storage are implemented as described above.

[0139] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, devices (systems), computer equipment or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0140] The present invention is described with reference to a flowchart of a method according to an embodiment of the present invention. It should be understood that each process in the flowchart and a combination of processes in the flowchart can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the process in the flowchart. Figure 1 A device that specifies functions in a process or multiple processes.

[0141] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A function specified in a process or multiple processes.

[0142] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 The steps of a specified function in a process or multiple processes.

Claims

1. A method for information-physical fusion modeling of an off-grid microgrid with distributed source and storage, characterized in that: The method comprises the following steps: A physical model of the microgrid is constructed according to the physical characteristics of the microgrid to describe the basic logic of the operation of the microgrid. The distributed source and storage of the microgrid include a wind turbine unit, a photovoltaic unit, and an energy storage unit. The physical model represents the continuous operation law of the wind turbine unit, the photovoltaic unit, and the energy storage unit. The information characteristics of each unit of the microgrid are represented by the finite state machine, and the basic information model of each unit equipment of the microgrid is established; According to the physical model and the information basic model, based on the operating characteristics and control strategies of different devices in the microgrid, the information physical models of the source storage units of the microgrid are respectively established; Based on the information-physical model of the microgrid source-storage unit, a hybrid logic dynamic method is used to consider the control state change events of each distributed source-storage unit in the microgrid and information-physical fusion to establish a microgrid information-physical model.

2. The method according to claim 1, characterized in that The finite state machine is used to represent the information characteristics of each unit of the microgrid, and the basic information model of each unit equipment of the microgrid is established, including: The finite state machine tool is used to represent the state of each unit device in the microgrid, and the driving events of each state transition are listed. When different events occur, the finite state machine will drive each unit device to transfer and transform the state and display it, thus obtaining the information basic model of each unit device in the microgrid; Among them, the trajectory of each unit device starts from the initial state (s1, x1), and the conversion process includes the evolution of the continuous state and the switching of the operating state. When the initial operating state is s1, the continuous variable x evolves according to the following differential equation: Where f represents the continuous dynamic change relationship function of the controlled object at this time, and x(0) represents the x value at time 0.

3. The method according to claim 1, characterized in that According to the physical model and the information basic model, based on the operating characteristics and control strategies of different devices in the microgrid, information physical models of the source storage unit of the microgrid are established respectively, including: Based on the switching control concept, for wind power units, the operating state is determined by the wind speed; for photovoltaic units, the operating state is determined by the constant power reference value; For energy storage units, the operating states are divided according to their state of charge.

4. The method according to claim 3, characterized in that The photovoltaic unit is divided into two operating states: fixed power output state and maximum output power state. The dividing point between the two states is the fixed power reference value P. ref , by comparing the constant power reference value P of the photovoltaic unit ref and the maximum output power P max Determine which operating state it is working in. The operating characteristics of the photovoltaic unit are expressed as:

5. The method according to claim 3, characterized in that: The fan unit has two operating states: when the wind speed v is greater than the cut-in wind speed v in Less than rated wind speed v n The wind turbine will run in the maximum power tracking mode when the wind speed v is less than the cut-in wind speed v in When or above the rated wind speed v n When the fan is turned off, it will run in shutdown mode, and the output characteristic of the fan can be described as follows:

6. The method according to claim 3, characterized in that For energy storage units, when the state of charge of the energy storage unit is lower than the minimum allowable value SOC min When the state of charge is greater than the maximum allowable value SOC max When the state of charge is between the maximum allowable value and the minimum allowable value, the energy storage unit will choose to operate in charging mode or discharging mode according to system requirements. The operating characteristics of the energy storage unit are as follows: Where: SOC(t) and SOC(t-1) represent the state of charge of the energy storage unit at time t and t-1 respectively; Bat c Indicates the capacity of the energy storage unit; η COV Represents the conversion efficiency of the converter; η ch and η dch Respectively represent the charging and discharging efficiency of BSS; P input (t) represents the sum of the power input to the BSS at this moment. If the input power of the energy storage unit is greater than the load demand, that is, P input (t)>P load (t), the load is supplied first, and the remaining power is used to charge the energy storage unit; if P input (t)≤P load (t), the generated power will be used to supply the load, and the insufficient power will be provided by the energy storage unit.

7. The method according to claim 1, characterized in that Using the hybrid logic dynamic method, the control state change events of each distributed source and storage in the microgrid and the information-physical fusion are considered to establish the microgrid information-physical model, including: The state of the microgrid system includes the state set of its unit devices, and the state of the microgrid system is defined as follows: S=(e1,e2,e3,......,e n ) Among them, S represents the system state; e i Indicates the status of each unit device in the system, i = 1, 2, 3...; n is the number of system devices; whenever the external environment or system instructions change, the corresponding device undergoes state transfer due to the corresponding event drive, and the entire system state changes; the system state is included in the finite set, and whenever the state is converted, the finite state machine tool can display various related indicators and event states; Based on the information-physical models of the source and storage units, the hybrid logic dynamic method is used to design the logic variables and convert the logic information in the microgrid into equation form. The hybrid logic dynamic model of the microgrid is as follows: x(t+1)=A i x(t)+B u u(t)+B 2t δ(t)+B 3t z(t) y(t)=C i x(t)+D u u(t)+D 2t δ(t)+D 3t z(t) E 2t δ(t)+E 3t z(t)≤E 4t x(t)+E 1t u(t)+E 5t In the formula, x(t), u(t), y(t) are the continuous variable, control variable and output variable of the controlled object respectively; δ(t) is the logical variable; z(t) is the auxiliary variable; E nt is the state transition mapping; A, B, C, D are the coefficients of the corresponding variables; The microgrid hybrid logic dynamic model is used as the microgrid information physical model.

8. An off-grid microgrid information-physical fusion modeling system with distributed source and storage, characterized in that: include: A physical model building module is used to build a physical model of the microgrid according to the physical characteristics of the microgrid, and describe the basic logic of the operation of the microgrid. The distributed source and storage of the microgrid include a wind turbine unit, a photovoltaic unit, and an energy storage unit. The physical model represents the continuous operation law of the wind turbine unit, the photovoltaic unit, and the energy storage unit. An information model building module is used to use a finite state machine to represent the information characteristics of each unit of the microgrid and establish an information basic model of each unit device of the microgrid; The information-physical model construction module is used to establish the information-physical models of the microgrid source-storage units according to the physical model and the information basic model, based on the operating characteristics and control strategies of different devices in the microgrid; and based on the information-physical model of the microgrid source-storage units, a hybrid logic dynamic method is used to consider the control state change events of each distributed source and storage of the microgrid and information-physical fusion to establish the microgrid information-physical model.

9. The system according to claim 8, characterized in that The information characteristics of each unit of the microgrid are represented by the finite state machine, and the information basic model of each unit equipment of the microgrid is established, including: The finite state machine tool is used to represent the state of each unit device in the microgrid, and the driving events of each state transition are listed. When different events occur, the finite state machine will drive each component to transfer and transform the state and display it, thus obtaining the information basic model of each unit device in the microgrid; Among them, the trajectory of each unit device starts from the initial state (s1, x1), and the conversion process includes the evolution of the continuous state and the switching of the operating state. When the initial operating state is s1, the continuous variable x evolves according to the following differential equation: Where f represents the continuous dynamic change relationship function of the controlled object at this time, and x(0) represents the x value at time 0.

10. The system according to claim 8, characterized in that According to the physical model and the information basic model, based on the operating characteristics and control strategies of different devices in the microgrid, information physical models of the source storage unit of the microgrid are established respectively, including: Based on the switching control concept, for wind power units, the operating state is determined by the wind speed; for photovoltaic units, the operating state is determined by the constant power reference value; For energy storage units, the operating states are divided according to their state of charge.

11. The system according to claim 10, characterized in that The photovoltaic unit is divided into two operating states: fixed power output state and maximum output power state. The dividing point between the two states is the fixed power reference value P. ref , by comparing the constant power reference value P of the photovoltaic unit ref and the maximum output power P max Determine which operating state it is working in. The operating characteristics of the photovoltaic unit are expressed as:

12. The system according to claim 10, characterized in that The fan unit has two operating states: when the wind speed v is greater than the cut-in wind speed v in Less than rated wind speed v n The wind turbine will run in the maximum power tracking mode when the wind speed v is less than the cut-in wind speed v in When or above the rated wind speed v n When the fan is turned off, it will run in shutdown mode, and the output characteristic of the fan can be described as follows:

13. The system according to claim 10, characterized in that For energy storage units, when the state of charge of the energy storage unit is lower than the minimum allowable value SOC min When the state of charge is greater than the maximum allowable value SOC max When the state of charge is between the maximum allowable value and the minimum allowable value, the energy storage unit will choose to operate in charging mode or discharging mode according to system requirements. The operating characteristics of the energy storage unit are as follows: Where: SOC(t) and SOC(t-1) represent the state of charge of the energy storage unit at time t and t-1 respectively; Bat c Indicates the capacity of the energy storage unit; η COV Represents the conversion efficiency of the converter; η ch and η dch Respectively represent the charging and discharging efficiency of BSS; P input (t) represents the sum of the power input to the BSS at this moment. If the input power of the energy storage unit is greater than the load demand, that is, P input (t)>P load (t), the load is supplied first, and the remaining power is used to charge the energy storage unit; if P input (t)≤P load (t), the generated power will be used to supply the load, and the insufficient power will be provided by the energy storage unit.

14. The system according to claim 8, characterized in that Using the hybrid logic dynamic method, the control state change events of each distributed source and storage in the microgrid and the information-physical fusion are considered to establish the microgrid information-physical model, including: The state of the microgrid system includes the state set of its unit devices, and the state of the microgrid system is defined as follows: S=(e1,e2,e3,......,e n ) Among them, S represents the system state; e i Indicates the status of each unit device in the system, i = 1, 2, 3...; n is the number of system devices; whenever the external environment or system instructions change, the corresponding device undergoes state transfer due to the corresponding event drive, and the entire system state changes; the system state is included in the finite set, and whenever the state is converted, the finite state machine tool can display various related indicators and event states; Based on the information-physical models of the source and storage units, the hybrid logic dynamic method is used to design the logic variables and convert the logic information in the microgrid into equation form. The hybrid logic dynamic model of the microgrid is as follows: x(t+1)=A i x(t)+B u u(t)+B 2t δ(t)+B 3t z(t) y(t)=C i x(t)+D u u(t)+D 2t δ(t)+D 3t z(t) E 2t δ(t)+E 3t z(t)≤E 4t x(t)+E 1t u(t)+E 5t In the formula, x(t), u(t), y(t) are the continuous variable, control variable and output variable of the controlled object respectively; δ(t) is the logical variable; z(t) is the auxiliary variable; E nt is the state transition mapping; A, B, C, D are the coefficients of the corresponding variables; The microgrid hybrid logic dynamic model is used as the microgrid information physical model.

15. A computer device, characterized in that: include: one or more processors; Memory; And one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and when the programs are executed by the processors, the steps of the information-physical fusion modeling method for an off-grid microgrid containing distributed sources and storage are implemented as described in any one of claims 1-7.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the information-physical fusion modeling method for an off-grid microgrid containing distributed sources and storage are implemented as described in any one of claims 1-7.

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