A method and system for offline positioning of broadband oscillation sources in a wind-solar-storage grid-connected system

Abstract

The present invention discloses a method and system for offline positioning of a broadband oscillation source in a wind-solar-storage grid-connected system, wherein the method comprises: establishing a state-space equation of the wind-solar-storage grid-connected system based on model parameters of the wind-solar-storage grid-connected system; forming a Gramian matrix of the wind-solar-storage grid-connected system based on a system matrix, a control matrix, and an output matrix in the state-space equation of the wind-solar-storage grid-connected system, and determining a semi-positive definite matrix; forming a Gramian matrix of a basic system of wind power, photovoltaic power, and energy storage based on the semi-positive definite matrix; determining an interaction factor for quantifying broadband dynamic interactions between power electronic devices in the wind-solar-storage grid-connected system based on the Gramian matrix of the basic system of wind power, photovoltaic power, and energy storage; calculating the sum of the interaction factors between a single power electronic device and other power electronic devices, and locating the unit with the largest sum as the oscillation source.

Description

Technical Field

[0001] The present invention relates to the technical field of wind, solar, and storage grid-connected systems, and more specifically, to a method and system for offline positioning of a broadband oscillation source in a wind, solar, and storage grid-connected system. Background Art

[0002] With the construction of new power systems, renewable energy sources, such as wind power and photovoltaics, are rapidly developing. Their volatility and intermittency pose significant challenges to power system operation. To address these challenges, deploying energy storage alongside renewable energy generation is an effective way to smooth out these fluctuations and improve the scalability of renewable energy sources. However, the widespread grid connection of multiple power electronic devices, including wind power, photovoltaics, and energy storage, can trigger wideband dynamic interactions, jeopardizing the safe and stable operation of the power grid.

[0003] The dynamic interactions of power electronic devices within a system can trigger broadband oscillations. Offline calculation of potential oscillation sources under specific system conditions during grid planning and before project commissioning allows for the rapid and sequential removal of potentially impactful stations when oscillations occur, minimizing the probability of grid-connected accidents. Existing research has rarely examined offline methods for locating broadband oscillation sources in wind, solar, and energy storage grid-connected systems from the perspective of analyzing the interactions between power electronic devices. Summary of the Invention

[0004] According to the present invention, a method and system for offline positioning of a wide-band oscillation source in a wind-solar-storage grid-connected system are provided to solve the technical problem of how to offline position the wide-band oscillation source in a wind-solar-storage grid-connected system based on the dynamic interaction between power electronic devices.

[0005] According to a first aspect of the present invention, a method for offline positioning of a broadband oscillator source in a wind-solar-storage grid-connected system is provided, comprising:

[0006] Based on the model parameters of the wind-solar-storage grid-connected system, the state space equation of the wind-solar-storage grid-connected system is established;

[0007] Based on the system matrix, control matrix and output matrix in the state space equation of the wind-solar-storage grid-connected system, a Gram matrix of the wind-solar-storage grid-connected system is formed, and a semi-positive definite matrix is ​​determined;

[0008] Based on the semi-positive definite matrix, a Gram matrix of the basic systems of wind power, photovoltaic power and energy storage is formed;

[0009] Based on the Gram matrix of wind power, photovoltaic and energy storage basic systems, the interaction factors for quantifying the broadband dynamic interaction between power electronic devices in wind, photovoltaic and energy storage grid-connected systems are determined;

[0010] The sum of the interaction factors between a single power electronic device and other power electronic devices is calculated, and the unit with the largest sum is identified as the oscillation source.

[0011] Optionally, based on the model parameters of the wind-solar-storage grid-connected system, a state space equation of the wind-solar-storage grid-connected system is established, including:

[0012] The current of a single power electronic device is used as the input of a stable wind-solar-storage grid-connected system, and the port voltage is used as the output. The input at time t is an m×1-order vector u(t), and the output is an m×1-order vector y(t). The state space equation of the wind-solar-storage grid-connected system is:

[0013]

[0014] Where A is the system matrix, A∈Rn×n; B is the control matrix, B∈Rn×m; C is the output matrix, C∈Rm×n; x(t) is the system state variable.

[0015] Optionally, based on the system matrix, control matrix and output matrix in the state space equation of the wind-solar-storage grid-connected system, a Gram matrix of the wind-solar-storage grid-connected system is formed, including:

[0016] The controllable Gram matrix of the system is determined as shown in formula (2), which is used to quantify the controllability of the system input on the state. Its rank is equal to the dimension of the controllable subspace of the system:

[0017]

[0018] The observable Gram matrix of the system is determined as shown in formula (3), which is used to quantify the observability of the system state to the output. Its rank is equal to the dimension of the observable subspace of the system.

[0019]

[0020] Where P and Q are semi-positive matrices that satisfy Lyapunov equation (4):

[0021]

[0022] Optionally, based on the semi-positive definite matrix, a Gram matrix of a wind power, photovoltaic, and energy storage basic system is formed, including:

[0023] The multi-input multi-output wind-solar-storage grid-connected system (A, B, C) is separated into a set of single-input single-output basic systems (A, bi, cj). Each basic system has an input ui (i∈{1,2,…,m}) and an output yj (j∈{1,2,…,m}), and its Gram matrices Pi and Qj satisfy

[0024]

[0025] Where bi is the i-th column of B and cj is the j-th column of CT. Then (Pi,Qj) describes the ability of input ui and output yj to control and observe the system state.

[0026] Optionally, based on the Gram matrix of the wind power, photovoltaic, and energy storage basic systems, interaction factors for quantifying the broadband dynamic interaction between power electronic devices in the wind, photovoltaic, and energy storage grid-connected system are determined, including:

[0027] The interaction factor is defined as shown in formula (6). This indicator is used to measure the broadband dynamic interaction between power electronic devices in the wind-solar-storage grid-connected system. The product PiQj represents the interaction between input and output, and its trace is state-independent:

[0028]

[0029] Where tr represents the trace of the matrix, max[tr(Pi,Qj)] represents the maximum value among all tr(Pi,Qj), and Λij is a number between 0 and 1. The closer Λij is to 1, the greater the interaction between power electronic devices i and j. Conversely, the closer Λij is to 0, the smaller the interaction.

[0030] Optionally, the sum of interaction factors between a single power electronic device and other power electronic devices is calculated, and the unit with the largest sum is located as the oscillation source, including:

[0031] The interaction factors between power electronic device i and other power electronic devices are accumulated, as shown in formula (7). The accumulated results are sorted from large to small. The unit with the largest sum is identified as the oscillation source. When oscillation occurs, the unit is disconnected according to the sorting.

[0032]

[0033] According to another aspect of the present invention, there is also provided a broadband oscillation source offline positioning system for a wind-solar-storage grid-connected system, comprising:

[0034] Establish a state space equation module to establish the state space equation of the wind-solar-storage grid-connected system based on the model parameters of the wind-solar-storage grid-connected system;

[0035] A grid-connected system Gram matrix forming module is used to form a Gram matrix of the wind-solar-storage grid-connected system based on the system matrix, control matrix and output matrix in the state space equation of the wind-solar-storage grid-connected system, and determine a semi-positive definite matrix;

[0036] A basic system Gram matrix forming module is used to form the Gram matrix of the wind power, photovoltaic and energy storage basic systems based on the semi-positive definite matrix;

[0037] The interaction factor determination module is used to determine the interaction factors that quantify the broadband dynamic interaction between power electronic devices in the wind, photovoltaic and energy storage grid-connected system based on the Gram matrix of the wind power, photovoltaic and energy storage basic systems;

[0038] The oscillation source positioning module is used to calculate the sum of the interaction factors between a single power electronic device and other power electronic devices, and the unit with the largest sum is positioned as the oscillation source.

[0039] Optionally, a state-space equation module is established, including:

[0040] A state-space equation submodule is established to use the current of a single power electronic device as the input of a stable wind-solar-storage grid-connected system and the port voltage as the output. The input at time t is an m×1-order vector u(t), and the output is an m×1-order vector y(t). The state-space equation of the wind-solar-storage grid-connected system is:

[0041]

[0042] Where A is the system matrix, A∈Rn×n; B is the control matrix, B∈Rn×m; C is the output matrix, C∈Rm×n; x(t) is the system state variable.

[0043] Optionally, a grid-connected system Gram matrix module is formed, including:

[0044] The controllable Gram matrix determination submodule is used to determine the controllable Gram matrix of the system as shown in formula (2). It is used to quantify the controllability of the system input on the state. Its rank is equal to the dimension of the controllable subspace of the system:

[0045]

[0046] The observable Gram matrix determination submodule is used to determine the observable Gram matrix of the system as shown in formula (3), which is used to quantify the observability of the system state to the output. Its rank is equal to the dimension of the observable subspace of the system:

[0047]

[0048] Where P and Q are semi-positive matrices that satisfy Lyapunov equation (4):

[0049]

[0050] Optionally, a basic system Gram matrix module is formed, including:

[0051] Determine the basic system Gram matrix submodule, which is used to separate the multi-input multi-output wind-solar-storage grid-connected system (A, B, C) into a group of single-input single-output basic systems (A, B i ,c j), each basic system has an input u i (i∈{1,2,…,m}) and an output y j (j∈{1,2,…,m}), whose Gram matrix P i and Q j satisfy:

[0052]

[0053] Where b i is the i-th column of B, c j It is C T The jth column of , then (P i ,Q j ) describes the input u i and output y j The ability to control and observe the system status.

[0054] Optionally, determining an interaction factor module includes:

[0055] Define the interaction factor submodule, which is used to define the interaction factor as shown in formula (6). This indicator is used to measure the broadband dynamic interaction between power electronic devices in the wind-solar-storage grid-connected system. The product P i Q j Characterizes the interaction between input and output, and its trace is state-implementation-independent:

[0056]

[0057] Where tr represents the trace of the matrix, max[tr(P i ,Q j )] represents all tr(P i ,Q j ) in the maximum value, Λ ij is a number between 0 and 1, ij The closer it is to 1, the greater the interaction between power electronic devices i and j. ij The closer it is to 0, the smaller the interaction effect is.

[0058] Optionally, the positioning oscillation source module includes:

[0059] The oscillation source location submodule is used to accumulate the interaction factors between power electronic device i and other power electronic devices, as shown in formula (7). The accumulated results are sorted from large to small, and the unit with the largest sum is located as the oscillation source. When oscillation occurs, the unit is disconnected according to the sorting.

[0060]

[0061] According to another aspect of the present invention, there is also provided a broadband oscillation source offline positioning system for a wind-solar-storage grid-connected system, comprising:

[0062] Establish a state space equation module to establish the state space equation of the wind-solar-storage grid-connected system based on the model parameters of the wind-solar-storage grid-connected system;

[0063] A grid-connected system Gram matrix forming module is used to form a Gram matrix of the wind-solar-storage grid-connected system based on the system matrix, control matrix and output matrix in the state space equation of the wind-solar-storage grid-connected system, and determine a semi-positive definite matrix;

[0064] A basic system Gram matrix forming module is used to form the Gram matrix of the wind power, photovoltaic and energy storage basic systems based on the semi-positive definite matrix;

[0065] The interaction factor determination module is used to determine the interaction factors that quantify the broadband dynamic interaction between power electronic devices in the wind, photovoltaic and energy storage grid-connected system based on the Gram matrix of the wind power, photovoltaic and energy storage basic systems;

[0066] The oscillation source positioning module is used to calculate the sum of the interaction factors between a single power electronic device and other power electronic devices, and the unit with the largest sum is positioned as the oscillation source.

[0067] Optionally, a state-space equation module is established, including:

[0068] A state-space equation submodule is established to use the current of a single power electronic device as the input of a stable wind-solar-storage grid-connected system and the port voltage as the output. The input at time t is an m×1-order vector u(t), and the output is an m×1-order vector y(t). The state-space equation of the wind-solar-storage grid-connected system is:

[0069]

[0070] Where A is the system matrix, A∈R n×n ; B is the control matrix, B∈R n×m ; C is the output matrix, C∈R m×n ; x(t) is the system state variable.

[0071] Optionally, a grid-connected system Gram matrix module is formed, including:

[0072] The controllable Gram matrix determination submodule is used to determine the controllable Gram matrix of the system as shown in formula (2). It is used to quantify the controllability of the system input on the state. Its rank is equal to the dimension of the controllable subspace of the system:

[0073]

[0074] The observable Gram matrix determination submodule is used to determine the observable Gram matrix of the system as shown in formula (3), which is used to quantify the observability of the system state to the output. Its rank is equal to the dimension of the observable subspace of the system:

[0075]

[0076] Where P and Q are semi-positive matrices that satisfy Lyapunov equation (4):

[0077]

[0078] Optionally, a basic system Gram matrix module is formed, including:

[0079] Determine the basic system Gram matrix submodule, which is used to separate the multi-input multi-output wind-solar-storage grid-connected system (A, B, C) into a group of single-input single-output basic systems (A, B i ,c j ), each basic system has an input u i (i∈{1,2,…,m}) and an output y j (j∈{1,2,…,m}), whose Gram matrix P i and Q j satisfy:

[0080]

[0081] Where b i is the i-th column of B, c j It is C T The jth column of , then (P i ,Q j ) describes the input u i and output y j The ability to control and observe the system status.

[0082] Optionally, determining an interaction factor module includes:

[0083] Define the interaction factor submodule, which is used to define the interaction factor as shown in formula (6). This indicator is used to measure the broadband dynamic interaction between power electronic devices in the wind-solar-storage grid-connected system. The product P i Q j Characterizes the interaction between input and output, and its trace is state-implementation-independent:

[0084]

[0085] Where tr represents the trace of the matrix, max[tr(P i ,Q j )] represents all tr(P i ,Qj ) in the maximum value, Λ ij is a number between 0 and 1, ij The closer it is to 1, the greater the interaction between power electronic devices i and j. ij The closer it is to 0, the smaller the interaction effect is.

[0086] Optionally, the positioning oscillation source module includes:

[0087] The oscillation source location submodule is used to accumulate the interaction factors between power electronic device i and other power electronic devices, as shown in formula (7). The accumulated results are sorted from large to small, and the unit with the largest sum is located as the oscillation source. When oscillation occurs, the unit is disconnected according to the sorting.

[0088]

[0089] Therefore, from the perspective of the interaction between power electronic devices, the sum of the interactions between a single power electronic device and other power electronic devices can be quantitatively calculated. The accumulated results are sorted from large to small, and the unit with the largest sum is identified as the oscillation source. When oscillation occurs, the unit is disconnected based on the sorting. The technical solution of the present invention achieves offline positioning of broadband oscillation sources in wind, solar, and energy storage grid-connected systems. It can be easily extended to other renewable energy grid-connected scenarios and even more complex systems, and provides theoretical guidance for suppressing broadband oscillations in wind, solar, and energy storage grid-connected systems in actual engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0091] Figure 1 Schematic diagram of the process of offline positioning method of broadband oscillation source in wind-solar-storage grid-connected system according to this embodiment;

[0092] Figure 2 This is a typical structural diagram of two wind, solar and storage stations connected to the grid as described in this embodiment;

[0093] Figure 3 Schematic diagram of the control principle of a typical grid-connected converter according to this embodiment;

[0094] FIG4 is a schematic diagram of simulation results under different scenarios according to this embodiment;

[0095] Figure 5 Schematic diagram of an offline positioning system for a broadband oscillation source of a wind-solar-storage grid-connected system described in this embodiment. DETAILED DESCRIPTION

[0096] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to provide a thorough and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments shown in the accompanying drawings is not intended to limit the present invention. In the accompanying drawings, identical elements are denoted by the same reference numerals.

[0097] Unless otherwise specified, the terms used herein (including technical terms) have the meanings commonly understood by those skilled in the art. In addition, it is understood that terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0098] According to a first aspect of the present invention, a method 100 for offline positioning of a broadband oscillator source in a wind-solar-storage grid-connected system is provided. Figure 1 As shown, the method 100 includes:

[0099] S101: Based on the model parameters of the wind-solar-storage grid-connected system, a state space equation of the wind-solar-storage grid-connected system is established;

[0100] S102: Based on the system matrix, control matrix and output matrix in the state space equation of the wind-solar-storage grid-connected system, a Gram matrix of the wind-solar-storage grid-connected system is formed, and a semi-positive definite matrix is ​​determined;

[0101] S103: Based on the semi-positive definite matrix, a Gram matrix of the wind power, photovoltaic, and energy storage basic systems is formed;

[0102] S104: Based on the Gram matrix of the wind power, photovoltaic, and energy storage basic systems, determine the interaction factors for quantifying the broadband dynamic interaction between power electronic devices in the wind, photovoltaic, and energy storage grid-connected system;

[0103] S105: Calculate the sum of interaction factors between a single power electronic device and other power electronic devices, and locate the unit with the largest sum as the oscillation source.

[0104] Specifically, (1) establish the state space equation of the wind-solar-storage grid-connected system

[0105] For a stable wind-solar-storage grid-connected system, the current of a single power electronic device is taken as input and the port voltage is taken as output. The input at time t is an m×1 order vector u(t), and the output is an m×1 order vector y(t). The state space equation of the wind-solar-storage grid-connected system is:

[0106]

[0107] Where A is the system matrix, A∈R n×n ; B is the control matrix, B∈R n×m ; C is the output matrix, C∈R m×n ; x(t) is the system state variable.

[0108] (2) Forming the Gram matrix of the wind-solar-storage grid-connected system

[0109] The controllable Gram matrix of the system is shown in formula (2), which is used to quantify the controllability of the system input on the state. Its rank is equal to the dimension of the controllable subspace of the system:

[0110]

[0111] The observable Gram matrix of the system is shown in formula (3), which is used to quantify the degree of observability of the system state to the output. Its rank is equal to the dimension of the observable subspace of the system:

[0112]

[0113] P and Q are semi-positive definite matrices that satisfy Lyapunov equation (4):

[0114]

[0115] (3) Forming the Gram matrix of basic systems such as wind power, photovoltaics, and energy storage

[0116] The multi-input multi-output wind-solar-storage grid-connected system (A, B, C) can be separated into a group of single-input single-output basic systems (A, B i ,c j ), each basic system has an input u i (i∈{1,2,…,m}) and an output y j (j∈{1,2,…,m}), whose Gram matrix P i and Q j satisfy:

[0117]

[0118] Where: b i is the i-th column of B, c j It is C T The jth column of , then (P i ,Q j ) describes the input u i and output y j The ability to control and observe the system status.

[0119] (4) Quantifying the broadband dynamic interactions between power electronic devices in wind, solar, and storage grid-connected systems

[0120] Product P i Q j It can characterize the interaction between input and output, and its trace is state-independent. The interaction factor is defined as shown in Equation (6). This indicator can be used to measure the broadband dynamic interaction between power electronic devices in wind, solar, and storage grid-connected systems.

[0121]

[0122] Where tr represents the trace of the matrix, max[tr(P i ,Q j )] represents all tr(P i ,Q j ) in the maximum value, Λ ij is a number between 0 and 1, ij The closer it is to 1, the greater the interaction between power electronic devices i and j. ij The closer it is to 0, the smaller the interaction effect is.

[0123] (5) Oscillation source positioning of wind, solar and storage grid-connected systems

[0124] The interaction factors between power electronic device i and other power electronic devices are accumulated, as shown in formula (7). The accumulated results are sorted from large to small. The unit with the largest sum is identified as the oscillation source. When oscillation occurs, the unit is disconnected according to the sorting.

[0125]

[0126] Take a typical system with two wind, solar and storage stations connected to the grid as an example. Figure 2 As shown, u s is the equivalent power supply on the grid side, L1, L2 and L0 are the equivalent line inductances on the station side and the grid side respectively, i L1 、i L2 and i L0 is the corresponding line current.

[0127] In order to simplify the analysis, the whole system adopts the per unit system, and converts each parameter to the reference capacity S B and reference voltage V B The typical parameters used are shown in Table 1. wind1 、S PV1 、S stor1 are the wind turbine, photovoltaic, and energy storage capacities of wind-solar-storage system 1; S wind2 、S PV2 、S stor2 They are the wind turbine, photovoltaic, and energy storage capacity of wind-solar-storage system 2. The same type of power electronic equipment in each system is aggregated as the basic system. The control principle of a typical grid-connected converter is as follows: Figure 3As shown, the control parameters adopt typical values.

[0128] Table 1 Main simulation parameters selected for the example

[0129]

[0130]

[0131] against Figure 2 For the system shown in Figure 1, the state space equation in the dq coordinate system is established as shown in Equation (8). Where A is the system matrix, A∈R n×n ; B is the control matrix, B∈R n×m ; C is the output matrix, C∈R m×n ; x(t) is the system state variable; select the d-axis and q-axis components of the output current of each wind power, photovoltaic and energy storage basic system [Δi d ,Δi q ] T is the input variable, the d-axis and q-axis components of the port voltage [Δu d ,Δu q ] T is the output variable.

[0132]

[0133] The state variables involved in the whole system include: commutation inductor branch current i cd and i cq , system inductance branch current i sd and i sq , filter capacitor voltage u cfd and u cfq , inner and outer loop variables x, phase-locked loop variables x pll and phase angle θ pll .

[0134] Step 2: Form the Gram matrix of the wind-solar-storage grid-connected system

[0135] The controllable Gram matrix P and observable Gram matrix Q of the wind-solar-storage grid-connected system can be calculated by equations (2) and (3), respectively, where k = 1, 2, …, m, l = 1, 2, …, n, the rows of P correspond to state variables, and the columns correspond to inputs; the rows of Q correspond to outputs, and the columns correspond to state variables.

[0136]

[0137]

[0138] Step 3: Form the Gram matrix of basic systems such as wind power, photovoltaics, and energy storage

[0139] The controllable and observable Gram matrices of each wind power, photovoltaic, and energy storage basic system k can be calculated using Equation (5). The rows of P correspond to the state variables, and the columns correspond to the inputs of each basic system k; the rows of Q correspond to the outputs of each basic system k, and the columns correspond to the state variables.

[0140]

[0141] Step 4: Quantify the broadband dynamic interactions between power electronic devices in wind, solar, and storage grid-connected systems

[0142] Equation (6) allows us to calculate the broadband dynamic interactions between power electronic devices in a wind-solar-storage grid-connected system. For ease of presentation, this is represented by a matrix Λ, where rows correspond to the inputs of each basic system k and columns correspond to the outputs of each basic system k. The off-diagonal elements of the matrix Λ represent the interactions between devices.

[0143]

[0144] (5) Oscillation source positioning of wind, solar and storage grid-connected systems

[0145] According to formula (7), the interaction factors between power electronic device i and other power electronic devices can be accumulated. The wind turbine in system 1 with the largest sum is located as the oscillation source. The accumulated results are sorted from large to small. The order of machine shutdown when oscillation occurs is shown in Table 2.

[0146] Table 2. Machine switching sequence when oscillation occurs

[0147] Serial number Basic System 1 System 1 fan 2 System 2 fan 3 System 1 Photovoltaic 4 System 2 Photovoltaic 5 System 1 Energy Storage 6 System 2 Energy Storage

[0148] The effectiveness of the method is verified by simulation. Figure 2 Simulation results for different scenarios show that the wind and photovoltaic power generation in the wind-solar-storage system is ramped from 60% to 80% at 0.5s, and the corresponding units are removed at 5s. It can be seen that when both wind-solar-storage systems 1 and 2 are in operation, the system experiences broadband oscillations. This oscillation disappears after removing the wind turbine in wind-solar-storage system 1, which ranks first, as shown in Figure 4(a). However, after removing the photovoltaic unit in wind-solar-storage system 2, which ranks fourth, the oscillation persists, with only a slight decrease in amplitude, as shown in Figure 4(b).

[0149] Therefore, based on the established state-space equation of the wind-solar-storage grid-connected system, the Gram matrix of the complete system was calculated, and the Gram matrix of basic systems such as wind power, photovoltaics, and energy storage was separated. By quantifying the wide-band dynamic interaction between power electronic equipment in the system, the equipment removal sequence when oscillation occurs was calculated, and the offline positioning of the oscillation source was achieved.

[0150] Optionally, based on the model parameters of the wind-solar-storage grid-connected system, a state space equation of the wind-solar-storage grid-connected system is established, including:

[0151] The current of a single power electronic device is used as the input of a stable wind-solar-storage grid-connected system, and the port voltage is used as the output. The input at time t is an m×1-order vector u(t), and the output is an m×1-order vector y(t). The state space equation of the wind-solar-storage grid-connected system is:

[0152]

[0153] Where A is the system matrix, A∈R n×n ; B is the control matrix, B∈R n×m ; C is the output matrix, C∈R m×n ; x(t) is the system state variable.

[0154] Optionally, based on the system matrix, control matrix and output matrix in the state space equation of the wind-solar-storage grid-connected system, a Gram matrix of the wind-solar-storage grid-connected system is formed, including:

[0155] The controllable Gram matrix of the system is determined as shown in formula (2), which is used to quantify the controllability of the system input on the state. Its rank is equal to the dimension of the controllable subspace of the system:

[0156]

[0157] The observable Gram matrix of the system is determined as shown in formula (3), which is used to quantify the observability of the system state to the output. Its rank is equal to the dimension of the observable subspace of the system.

[0158]

[0159] Where P and Q are semi-positive matrices that satisfy Lyapunov equation (4);

[0160]

[0161] Optionally, based on the semi-positive definite matrix, a Gram matrix of a wind power, photovoltaic, and energy storage basic system is formed, including:

[0162] Separate the multi-input multi-output wind-solar-storage grid-connected system (A, B, C) into a group of single-input single-output basic systems (A, B i ,c j ), each basic system has an input u i (i∈{1,2,…,m}) and an output y j (j∈{1,2,…,m}), whose Gram matrix P i and Q j satisfy

[0163]

[0164] Where b i is the i-th column of B, c j It is C T The jth column of , then (P i ,Q j ) describes the input u i and output y j The ability to control and observe the system status.

[0165] Optionally, based on the Gram matrix of the wind power, photovoltaic, and energy storage basic systems, interaction factors for quantifying the broadband dynamic interaction between power electronic devices in the wind, photovoltaic, and energy storage grid-connected system are determined, including:

[0166] The interaction factor is defined as shown in formula (6). This indicator is used to measure the broadband dynamic interaction between power electronic devices in the wind-solar-storage grid-connected system. The product P i Q j Characterizes the interaction between input and output, and its trace is state-implementation-independent:

[0167]

[0168] Where tr represents the trace of the matrix, max[tr(P i ,Q j )] represents all tr(P i ,Q j ) in the maximum value, Λ ij is a number between 0 and 1, ij The closer it is to 1, the greater the interaction between power electronic devices i and j. ij The closer it is to 0, the smaller the interaction effect is.

[0169] Optionally, the sum of interaction factors between a single power electronic device and other power electronic devices is calculated, and the unit with the largest sum is located as the oscillation source, including:

[0170] The interaction factors between power electronic device i and other power electronic devices are accumulated, as shown in formula (7). The accumulated results are sorted from large to small. The unit with the largest sum is identified as the oscillation source. When oscillation occurs, the unit is disconnected according to the sorting.

[0171]

[0172] Therefore, from the perspective of the interaction between power electronic devices, the sum of the interactions between a single power electronic device and other power electronic devices can be quantitatively calculated. The accumulated results are sorted from large to small, and the unit with the largest sum is identified as the oscillation source. When oscillation occurs, the unit is disconnected based on the sorting. The technical solution of the present invention achieves offline positioning of broadband oscillation sources in wind, solar, and energy storage grid-connected systems. It can be easily extended to other renewable energy grid-connected scenarios and even more complex systems, and provides theoretical guidance for suppressing broadband oscillations in wind, solar, and energy storage grid-connected systems in actual engineering.

[0173] According to another aspect of the present invention, a broadband oscillation source offline positioning system 500 for a wind-solar-storage grid-connected system is provided. Figure 5 As shown, the system 500 includes:

[0174] Establishing a state space equation module 510, for establishing a state space equation of the wind-solar-storage grid-connected system based on the model parameters of the wind-solar-storage grid-connected system;

[0175] A grid-connected system Gram matrix forming module 520 is configured to form a Gram matrix of the wind-solar-storage grid-connected system based on the system matrix, control matrix, and output matrix in the state space equation of the wind-solar-storage grid-connected system, and determine a semi-positive definite matrix;

[0176] A basic system Gram matrix forming module 530 is used to form the Gram matrix of the wind power, photovoltaic and energy storage basic systems based on the semi-positive definite matrix;

[0177] An interaction factor determination module 540 is configured to determine, based on the Gram matrix of the wind power, photovoltaic, and energy storage basic systems, an interaction factor for quantifying the broadband dynamic interaction between power electronic devices in the wind, photovoltaic, and energy storage grid-connected system;

[0178] The oscillation source positioning module 550 is used to calculate the sum of the interaction factors between a single power electronic device and other power electronic devices, and locate the unit with the largest sum as the oscillation source.

[0179] Optionally, a state-space equation module is established, including:

[0180] A state-space equation submodule is established to use the current of a single power electronic device as the input of a stable wind-solar-storage grid-connected system and the port voltage as the output. The input at time t is an m×1-order vector u(t), and the output is an m×1-order vector y(t). The state-space equation of the wind-solar-storage grid-connected system is:

[0181]

[0182] Where A is the system matrix, A∈R n×n ; B is the control matrix, B∈R n×m; C is the output matrix, C∈R m×n ; x(t) is the system state variable.

[0183] Optionally, a grid-connected system Gram matrix module is formed, including:

[0184] The controllable Gram matrix determination submodule is used to determine the controllable Gram matrix of the system as shown in formula (2). It is used to quantify the controllability of the system input on the state. Its rank is equal to the dimension of the controllable subspace of the system:

[0185]

[0186] Determine the observable Gram matrix submodule, which is used to determine the observable Gram matrix of the system as shown in formula (3), which is used to quantify the observability of the system state to the output, and its rank is equal to the dimension of the observable subspace of the system;

[0187]

[0188] Where P and Q are semi-positive matrices that satisfy Lyapunov equation (4);

[0189]

[0190] Optionally, a basic system Gram matrix module is formed, including:

[0191] Determine the basic system Gram matrix submodule, which is used to separate the multi-input multi-output wind-solar-storage grid-connected system (A, B, C) into a group of single-input single-output basic systems (A, B i ,c j ), each basic system has an input u i (i∈{1,2,…,m}) and an output y j (j∈{1,2,…,m}), whose Gram matrix P i and Q j satisfy

[0192]

[0193] Where b i is the i-th column of B, c j It is C T The jth column of , then (P i ,Q j ) describes the input u i and output y j The ability to control and observe the system status.

[0194] Optionally, determining an interaction factor module includes:

[0195] Define the interaction factor submodule, which is used to define the interaction factor as shown in formula (6). This indicator is used to measure the broadband dynamic interaction between power electronic devices in the wind-solar-storage grid-connected system. The product P i Q j Characterizes the interaction between input and output, and its trace is state-implementation-independent:

[0196]

[0197] Where tr represents the trace of the matrix, max[tr(P i ,Q j )] represents all tr(P i ,Q j ) in the maximum value, Λ ij is a number between 0 and 1, ij The closer it is to 1, the greater the interaction between power electronic devices i and j. ij The closer it is to 0, the smaller the interaction effect is.

[0198] Optionally, the positioning oscillation source module includes:

[0199] The oscillation source location submodule is used to accumulate the interaction factors between power electronic device i and other power electronic devices, as shown in formula (7). The accumulated results are sorted from large to small, and the unit with the largest sum is located as the oscillation source. When oscillation occurs, the unit is disconnected according to the sorting.

[0200]

[0201] An offline positioning system 500 for a broadband oscillator source in a wind-solar-storage grid-connected system according to an embodiment of the present invention corresponds to an offline positioning method 100 for a broadband oscillator source in a wind-solar-storage grid-connected system according to another embodiment of the present invention, and will not be described in detail here.

[0202] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the application can adopt 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.) that contain computer-usable program code. The scheme in the embodiment of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal translation scripting language JavaScript, etc.

[0203] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, 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 steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0204] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work 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 process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0205] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0206] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0207] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for offline positioning of broadband oscillation sources in a wind-solar-storage grid-connected system, characterized in that: include: Based on the model parameters of the wind-solar-storage grid-connected system, the state space equation of the wind-solar-storage grid-connected system is established; Based on the system matrix, control matrix and output matrix in the state space equation of the wind-solar-storage grid-connected system, a Gram matrix of the wind-solar-storage grid-connected system is formed, and a semi-positive definite matrix is ​​determined; Based on the semi-positive definite matrix, a Gram matrix of the basic systems of wind power, photovoltaic power and energy storage is formed; Based on the Gram matrix of wind power, photovoltaic and energy storage basic systems, the interaction factors for quantifying the broadband dynamic interaction between power electronic devices in wind, photovoltaic and energy storage grid-connected systems are determined; Calculate the sum of the interaction factors between a single power electronic device and other power electronic devices, and locate the unit with the largest sum as the oscillation source; Based on the Gram matrix of wind power, photovoltaic and energy storage basic systems, the interaction factors that quantify the broadband dynamic interaction between power electronic devices in the wind, photovoltaic and energy storage grid-connected system are determined, including: The interaction factor is defined as shown in the formula. This interaction factor is used to measure the broadband dynamic interaction between power electronic devices in the wind-solar-storage grid-connected system. The product P i Q j Characterizes the interaction between input and output, and its trace is state-implementation-independent: Where tr represents the trace of the matrix, max[tr(P i ,Q j )] represents all tr(P i ,Q j ) in the maximum value, Λ ij is a number between 0 and 1, ij The closer it is to 1, the greater the interaction between power electronic devices i and j. ij The closer it is to 0, the smaller the interaction effect is.

2. The method according to claim 1, characterized in that Based on the model parameters of the wind-solar-storage grid-connected system, the state space equation of the wind-solar-storage grid-connected system is established, including: For a stable wind-solar-storage grid-connected system, the current of a single power electronic device is taken as input and the port voltage is taken as output. The input at time t is an m×1-order vector u(t), and the output is an m×1-order vector y(t). The state space equation of the wind-solar-storage grid-connected system is: Where A is the system matrix, A∈R n×n ; B is the control matrix, B∈R n×m ; C is the output matrix, C∈R m×n ; x(t) is the system state variable.

3. The method according to claim 2, characterized in that Based on the system matrix, control matrix and output matrix in the state space equation of the wind-solar-storage grid-connected system, a Gram matrix of the wind-solar-storage grid-connected system is formed, including: The controllable Gram matrix of the system is determined as shown in formula (2), which is used to quantify the controllability of the system input on the state. Its rank is equal to the dimension of the controllable subspace of the system: Determine the observable Gram matrix of the system as shown in formula (3), which is used to quantify the observability of the system state to the output. Its rank is equal to the dimension of the observable subspace of the system: Where P and Q are semi-positive matrices that satisfy Lyapunov equation (4):

4. The method according to claim 1, wherein Based on the semi-positive definite matrix, the Gram matrix of the wind power, photovoltaic and energy storage basic systems is formed, including: Separate the multi-input multi-output wind-solar-storage grid-connected system (A, B, C) into a group of single-input single-output basic systems (A, B i ,c j ), each basic system has an input u i (i∈{1,2,…,m}) and an output y j (j∈{1,2,…,m}), whose Gram matrix P i and Q j satisfy: Where b i is the i-th column of B, c j is the jth column of C, then (P i ,Q j ) describes the input u i and output y j The ability to control and observe the system status.

5. The method according to claim 1, wherein Calculate the sum of the interaction factors between a single power electronic device and other power electronic devices. The unit with the largest sum is identified as the oscillation source, including: The interaction factors between power electronic device i and other power electronic devices are accumulated, as shown in formula (6). The accumulated results are sorted from large to small. The unit with the largest sum is identified as the oscillation source. When oscillation occurs, the unit is disconnected according to the sorting:

6. A broadband oscillation source offline positioning system for a wind, solar, and energy storage grid-connected system, characterized in that: include: Establish a state space equation module to establish the state space equation of the wind-solar-storage grid-connected system based on the model parameters of the wind-solar-storage grid-connected system; A grid-connected system Gram matrix forming module is used to form a Gram matrix of the wind-solar-storage grid-connected system based on the system matrix, control matrix and output matrix in the state space equation of the wind-solar-storage grid-connected system, and determine a semi-positive definite matrix; A basic system Gram matrix forming module is used to form the Gram matrix of the wind power, photovoltaic and energy storage basic systems based on the semi-positive definite matrix; The interaction factor determination module is used to determine the interaction factors that quantify the broadband dynamic interaction between power electronic devices in the wind, photovoltaic and energy storage grid-connected system based on the Gram matrix of the wind power, photovoltaic and energy storage basic systems; The oscillation source location module is used to calculate the sum of the interaction factors between a single power electronic device and other power electronic devices, and the unit with the largest sum is located as the oscillation source; Determine the interaction factor module, including: Define the interaction factor submodule, which is used to define the interaction factor as shown in the formula. The interaction factor is used to measure the broadband dynamic interaction between power electronic devices in the wind-solar-storage grid-connected system. The product P i Q j Characterizes the interaction between input and output, and its trace is state-implementation-independent: Where tr represents the trace of the matrix, max[tr(P i ,Q j )] represents all tr(P i ,Q j ) in the maximum value, Λ ij is a number between 0 and 1, ij The closer it is to 1, the greater the interaction between power electronic devices i and j. ij The closer it is to 0, the smaller the interaction effect is.

7. The system according to claim 6, characterized in that Build the state-space equation module, including: A state-space equation submodule is established to use the current of a single power electronic device as the input of a stable wind-solar-storage grid-connected system and the port voltage as the output. The input at time t is an m×1-order vector u(t), and the output is an m×1-order vector y(t). The state-space equation of the wind-solar-storage grid-connected system is: Where A is the system matrix, A∈R n×n ; B is the control matrix, B∈R n×m ; C is the output matrix, C∈R m×n ; x(t) is the system state variable.

8. The system according to claim 7, characterized in that The Gram matrix module of the grid-connected system is formed, including: The controllable Gram matrix determination submodule is used to determine the controllable Gram matrix of the system as shown in formula (2). It is used to quantify the controllability of the system input on the state. Its rank is equal to the dimension of the controllable subspace of the system: The observable Gram matrix determination submodule is used to determine the observable Gram matrix of the system as shown in formula (3), which is used to quantify the observability of the system state to the output. Its rank is equal to the dimension of the observable subspace of the system: Where P and Q are semi-positive matrices that satisfy Lyapunov equation (4):

9. The system according to claim 6, wherein: The basic system Gram matrix module is formed, including: Determine the basic system Gram matrix submodule, which is used to separate the multi-input multi-output wind-solar-storage grid-connected system (A, B, C) into a group of single-input single-output basic systems (A, B i ,c j ), each basic system has an input u i (i∈{1,2,…,m}) and an output y j (j∈{1,2,…,m}), whose Gram matrix P i and Q j satisfy Where b i is the i-th column of B, c j is the jth column of C, then (P i ,Q j ) describes the input u i and output y j The ability to control and observe the system status.

10. The system according to claim 6, wherein: Positioning oscillation source module, including: The oscillation source positioning submodule is used to accumulate the interaction factors between power electronic device i and other power electronic devices, as shown in formula (6), sort the accumulated results from large to small, and locate the unit with the largest sum as the oscillation source. When oscillation occurs, the unit is cut off according to the sorting.

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