A distributed economic dispatch method for microgrids based on finite-time event triggering

Abstract

The present invention discloses a distributed economic dispatch method for a microgrid based on finite-time event triggering, and belongs to the field of renewable energy power generation. First, a finite-time consistency economic dispatch algorithm is designed based on multi-agent consistency, and an event triggering condition for incremental cost is designed. Then, when the triggering condition is met, the finite-time consistency economic dispatch algorithm is used to update the incremental cost of the generator and calculate the power output of the generator. Then, an incremental cost correction term is introduced for the power output limit of the generator, and the event triggering condition of the incremental cost correction term is designed using the finite-time consistency economic dispatch algorithm and the incremental cost correction term is updated. The incremental cost is updated using the incremental cost correction term, and the power output of the generator is calculated so that the power output of the generator meets the power limit. The present invention can realize the economic dispatch of the microgrid within a limited time and save communication resources.

Description

Technical Field

[0001] The present invention belongs to the field of renewable energy power generation, and in particular to a microgrid distributed economic dispatching method based on finite time event triggering. Background Art

[0002] A microgrid is a small-scale power system that can be connected to a traditional power grid or operate independently. Microgrids are usually composed of a variety of energy resources, including renewable energy (such as solar energy, wind energy) and traditional energy (such as natural gas), as well as energy storage systems (such as batteries). They can provide electricity to homes, commercial buildings, industrial facilities or entire communities. Microgrids play an important role in achieving sustainable energy development and improving the reliability of energy supply. Economic dispatch is related to the safe and stable operation of microgrids and is an important part of microgrid control. Efficient dispatch can improve the reliability and stability of microgrid operation, reduce operating costs, and increase social benefits. It is of great significance to the development of microgrids. The economic dispatch problem of microgrids is to achieve the goal of minimizing the operating cost of the entire microgrid and reasonably allocate the output of each generator under the conditions of satisfying the supply and demand balance constraints of the entire microgrid and the power constraints of each generator. In order to solve the economic dispatch problem of microgrids, a large number of algorithms have been proposed. These algorithms can be divided into centralized economic dispatch algorithms and distributed economic dispatch algorithms according to whether a centralized controller is required. However, as the traditional centralized power network is developing in a distributed direction, these centralized algorithms face many challenges. First, centralized algorithms require centralized controllers, which need to be connected to each power device, send control instructions, and send the final decision results to each power generation device. Therefore, this leads to the centralized algorithm requiring a high communication investment, which increases the cost. At the same time, the centralized algorithm is very sensitive to single point failures. Once a failure occurs somewhere, the entire power system is in danger of collapse. On the other hand, in the future development of microgrids, the system topology and communication topology of microgrids will develop from centralized to distributed. At the same time, future microgrids have strong time-varying characteristics, which increases the communication and computing pressure of centralized algorithms and reduces the operating efficiency of centralized algorithms.

[0003] In order to overcome the shortcomings of the centralized economic dispatch algorithm, a distributed economic dispatch algorithm is adopted to perform economic dispatch of the microgrid. The distributed economic dispatch algorithm does not require a central controller. Compared with the traditional centralized economic dispatch algorithm, it has the advantages of higher flexibility, better robustness, and reduced system communication burden.

[0004] Most distributed economic dispatch algorithms are based on time-triggered mechanisms. Distributed economic dispatch based on event triggering can effectively reduce the communication burden of the system. The basic idea of ​​event triggering is to relax periodic sampling to non-periodic sampling while ensuring system performance. Compared with the time-triggered mechanism based on fixed-periodic sampling, a significant feature of the event triggering mechanism is that the time of sampling or control update is determined by the event triggering conditions given in advance. It can be seen that the event triggering mechanism can effectively reduce unnecessary communication and computing resource consumption while meeting system performance by adjusting the sampling frequency in real time. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a microgrid distributed economic dispatching method based on finite time event triggering in view of the defects of the above-mentioned prior art.

[0006] The present invention is implemented by the following scheme: A distributed economic dispatching method of a microgrid based on finite time event triggering, comprising the following steps:

[0007] Step S1: Establish a microgrid economic dispatch problem model, which includes the power generation cost function of the generator in the microgrid, the objective function of the economic dispatch problem, the supply and demand balance constraint condition of the generator power output, and the limit constraint condition of the generator power output;

[0008] Step S2: setting the initial value of the output power of each generator, and calculating the initial value of the incremental cost through the initial value of the generator power output;

[0009] Step S3: Select the incremental cost of the generator as the consistency variable, design a finite time consistency economic dispatch algorithm based on multi-agent consistency; design the event triggering condition of the incremental cost of the generator according to the finite time consistency economic dispatch algorithm;

[0010] Step S4: Use the finite time consistency economic dispatch algorithm and the event triggering condition of the incremental cost to update the incremental cost of the generator, and calculate the power output of the generator according to the incremental cost of the generator; determine whether the incremental cost of the generator reaches a consistency, if the incremental cost of the generator reaches a consistency, proceed to step S5, otherwise continue to step S4;

[0011] Step S5: Introduce an incremental cost correction term and set an initial value of the incremental cost correction term; use a finite time consistency economic dispatch algorithm to design an event trigger condition for the incremental cost correction term;

[0012] Step S6: Use the finite-time consistency economic dispatch algorithm and the event triggering conditions of the incremental cost correction item to update the incremental cost correction item, use the incremental cost correction item to update the incremental cost of the generator, and calculate the power output of the generator based on the incremental cost of the generator; determine whether the power output of each generator exceeds the limit value, if the power output is greater than its maximum value, set the power output to its maximum value; if the power output is less than its minimum value, set the power output to its minimum value, otherwise the power output of the generator remains unchanged; then determine whether the incremental cost correction item reaches a consistency, if the incremental cost correction item reaches a consistency, output the optimal incremental cost and optimal power output of the generator, otherwise continue with step S6.

[0013] Furthermore, the step S1 establishes a microgrid economic dispatch problem model, which includes the power generation cost function of the generator in the microgrid, the objective function of the economic dispatch problem, the supply and demand balance constraint condition of the generator power output and the limit constraint condition of the generator power output, specifically:

[0014] The power generation cost function of the generator in the microgrid is specifically:

[0015]

[0016] Where i = 1, 2, ..., n; n is the number of generators in the microgrid; C i (p i (t)) is the power generation cost function of the i-th generator; p i (t) is the power output of the i-th generator at time t; α i >0, β i >0 and γ i >0 is the power generation cost coefficient of the i-th generator;

[0017] The objective function of the economic dispatch problem, the supply and demand balance constraints of the generator power output, and the limit constraints of the generator power output are:

[0018]

[0019] in, is the objective function of the economic dispatch problem; is the supply and demand balance constraint of the generator power output; is the constraint condition of generator power output; PD is the total power demand, is the minimum power output limit of the i-th generator, is the maximum power output limit of the i-th generator.

[0020] Furthermore, the step S2 specifically includes the following steps:

[0021] Set the initial values ​​of the required parameters. The initial power output value of the i-th generator is p i (0), let P D is the total power demand, and the initial value of the incremental cost of the generator is calculated by the initial value of the generator power output. The initial value of the incremental cost of the i-th generator is λ i (0) = 2α i p i (0)+β i .

[0022] Furthermore, the step S3 specifically includes the following steps:

[0023] Step S31: Select the incremental cost of the generator as the consistency variable, and design a finite time consistency economic dispatch algorithm based on multi-agent consistency:

[0024]

[0025] e i (t)-e j (t))| u

[0026] Where i = 1, 2, ..., n; n is the number of generators in the microgrid; sign(·) is the sign function; λ i (t) is the incremental cost of the i-th generator at time t, is the derivative of the incremental cost of the i-th generator at time t; e i (t) is the state error of the i-th generator at time t, defined as: is the kth triggering moment of the i-th generator; θ is the gain coefficient, which is used to adjust the convergence speed of the algorithm; a ij is the adjacency weight of generator i and generator j; u∈(0,1) is the ratio of two positive odd numbers;

[0027] Step S32: The event triggering conditions for designing the incremental cost of the generator according to the finite time consistency economic dispatch algorithm are specifically:

[0028]

[0029] in, is the i-th element of Lλ(t), λ(t) is the incremental cost column vector of each generator at time t, specifically λ(t) = [λ1(t), λ2(t), λ3(t), ..., λ n (t)] T ; n is the number of generators in the microgrid, L = (l ij ) n×nis the Laplace matrix of the microgrid communication topology, l ij =-a ij (i≠j), i=1, 2, ..., n; j=1, 2, ...n; σ>0 is the event threshold; inf is the lower bound.

[0030] Furthermore, the step S4 specifically includes the following steps:

[0031] When the i-th generator f i When (t)>0, the event triggering condition of the generator incremental cost is met, let The incremental cost of the generator is updated using the finite time consistency economic dispatch algorithm; the power output of the generator is calculated using the incremental cost of the generator as:

[0032]

[0033] Determine whether the incremental cost of the generator is consistent. If the incremental cost of the generator is consistent, proceed to step S5, otherwise proceed to step S4; wherein the condition for the incremental cost of the generator to be consistent is:

[0034]

[0035] in, is the average value of the incremental cost of all generators, and μ1>0 is the consistency coefficient.

[0036] Furthermore, the step S5: introduces an incremental cost correction term and sets an initial value of the incremental cost correction term; uses a finite time consistency economic dispatch algorithm to design an event trigger condition for the incremental cost correction term, specifically:

[0037] Step S51: Introducing the incremental cost correction term q i (t) and z i (t), set the initial values ​​of the two incremental cost correction items as follows:

[0038]

[0039] Step S52: Use the finite time consistency economic dispatch algorithm to design the event triggering conditions of the incremental cost correction term, specifically:

[0040] According to the finite time consistency economic dispatch algorithm, the event trigger conditions are designed as follows:

[0041]

[0042] in, and are the i-th elements of Lq(t) and Lz(t), respectively. q(t) and z(t) are the column vectors of the incremental cost correction items of each generator at time t, specifically q(t) = [q1(t), q2(t), q3(t), ..., q n (t)] T ,z(t)=[z1(t),z2(t),z3(t),...,z n (t)] T , i=1, 2, ..., n; n is the number of generators in the microgrid, τ>0, ρ>0 is the event threshold.

[0043] Furthermore, the step S6 specifically includes the following steps:

[0044] Step S61: Use the finite time consistency economic dispatch algorithm and the event triggering condition of the incremental cost correction term to update the incremental cost correction term, use the incremental cost correction term to update the incremental cost of the generator, and calculate the power output of the generator according to the incremental cost of the generator, specifically:

[0045] Using the finite time consistent economic dispatch algorithm and the event triggering condition of the incremental cost correction term, the incremental cost correction term is updated as follows:

[0046]

[0047]

[0048] Where i = 1, 2, ..., n; n is the number of generators in the microgrid; sign(·) is the sign function; q i (t) and z i (t) are two incremental cost correction items for incremental cost, and are the derivatives of the two incremental cost correction terms of the incremental cost at time t; eq i (t) and ez i (t) are the state errors of the incremental cost correction term of the i-th generator, which are defined as: ψ is the gain coefficient, which is used to adjust the convergence speed of the algorithm; v∈(0,1) and w∈(0,1) are the ratios of two positive odd numbers;

[0049] The incremental cost of updating the generator using the incremental cost modifier is:

[0050]

[0051] The incremental cost after reaching a consensus on the incremental cost of the generator; the power output of the generator is calculated based on the incremental cost of the generator:

[0052]

[0053] Step S62: Determine whether the power output of each generator exceeds the limit value. If the power output is greater than its maximum value, set the power output to its maximum value; if the power output is less than its minimum value, set the power output to its minimum value; otherwise, the power output of the generator remains unchanged. Specifically:

[0054]

[0055] When the generator power output When the generator power output is When the generator power output When the generator power output is When the generator power output When the generator power output is kept constant, p i (t) = p i (t);

[0056] Step S63: Determine whether the incremental cost correction items are consistent. If the incremental cost correction items are consistent, then output the optimal incremental cost and optimal power output of the generator. Otherwise, proceed to step S6. The conditions for the incremental cost correction items to be consistent are:

[0057]

[0058]

[0059] in, and They are the incremental cost correction terms q i (t) and z i (t) is the average value; μ2>0 and μ3>0 are the consistency coefficients.

[0060] The present invention provides a microgrid distributed economic dispatch method based on finite time event triggering. Compared with the prior art, the present invention has the following beneficial effects:

[0061] 1. The distributed economic dispatch method proposed in the present invention can quickly make the optimal dispatch decision within a limited time, which enables the system to respond to emergencies or load fluctuations in a timely manner, thereby improving the flexibility and robustness of the system.

[0062] 2. The distributed economic dispatch method proposed in the present invention is completely distributed. Its main advantage over centralized economic dispatch is its enhanced system resilience and robustness. Since the distributed method allows each distributed energy resource to independently make optimal decisions based on local information and information from neighboring nodes, the system can continue to operate at the local optimal level when facing communication failures, local equipment failures, or market changes. The overall system is more adaptable to various uncertainties and disturbances and maintains stable operation.

[0063] 3. The event-triggered economic dispatch method proposed in the present invention realizes on-demand utilization of system resources by activating the dispatch decision only when the triggering conditions are met. This method can significantly reduce unnecessary computing and communication overhead, improve the real-time and flexibility of dispatch, reduce the operating cost of the system, and improve the overall economy and reliability.

[0064] 4. The generator power output solved by the distributed economic dispatch method proposed in the present invention satisfies both the generator supply and demand balance constraint and the generator power output limit constraint. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a flow chart of a distributed economic dispatching method of a microgrid based on finite time event triggering according to the present invention;

[0066] Figure 2 The IEEE 14-node standard power network of the present invention;

[0067] Figure 3 The communication topology diagram of each generator of the present invention;

[0068] Figure 4 is the incremental cost λ of each generator of the present invention i (t) Changes over time;

[0069] Figure 5 is the power output p of each generator of the present invention i (t) time-varying graph;

[0070] Figure 6 is an event triggering time diagram of each generator under the incremental cost event triggering condition of the present invention;

[0071] Figure 7 The total power generation cost of the present invention is Time-varying graphs;

[0072] Figure 8 is the incremental cost correction term q of the present invention i (t) Changes over time;

[0073] Fig. 9is the incremental cost correction term z of the present invention i (t) Variation with time. DETAILED DESCRIPTION

[0074] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0075] Embodiment 1:

[0076] The process of a microgrid distributed economic dispatching method based on finite time event triggering provided in this embodiment is as follows: Figure 1 As shown, the specific steps include:

[0077] Step S1: Establish a microgrid economic dispatch problem model, which includes the power generation cost function of the generator in the microgrid, the objective function of the economic dispatch problem, the supply and demand balance constraint condition of the generator power output, and the limit constraint condition of the generator power output;

[0078] Step S2: setting the initial value of the output power of each generator, and calculating the initial value of the incremental cost through the initial value of the generator power output;

[0079] Step S3: Select the incremental cost of the generator as the consistency variable, design a finite time consistency economic dispatch algorithm based on multi-agent consistency; design the event triggering condition of the incremental cost of the generator according to the finite time consistency economic dispatch algorithm;

[0080] Step S4: Use the finite time consistency economic dispatch algorithm and the event triggering condition of the incremental cost to update the incremental cost of the generator, and calculate the power output of the generator according to the incremental cost of the generator; determine whether the incremental cost of the generator reaches a consistency, if the incremental cost of the generator reaches a consistency, proceed to step S5, otherwise continue to step S4;

[0081] Step S5: Introduce an incremental cost correction term and set an initial value of the incremental cost correction term; use a finite time consistency economic dispatch algorithm to design an event trigger condition for the incremental cost correction term;

[0082] Step S6: Use the finite-time consistency economic dispatch algorithm and the event triggering conditions of the incremental cost correction item to update the incremental cost correction item, use the incremental cost correction item to update the incremental cost of the generator, and calculate the power output of the generator based on the incremental cost of the generator; determine whether the power output of each generator exceeds the limit value, if the power output is greater than its maximum value, set the power output to its maximum value; if the power output is less than its minimum value, set the power output to its minimum value, otherwise the power output of the generator remains unchanged; then determine whether the incremental cost correction item reaches a consistency, if the incremental cost correction item reaches a consistency, output the optimal incremental cost and optimal power output of the generator, otherwise continue with step S6.

[0083] In this embodiment, the step S1 establishes a microgrid economic dispatch problem model, which includes the power generation cost function of the generator in the microgrid, the objective function of the economic dispatch problem, the supply and demand balance constraint condition of the generator power output and the limit constraint condition of the generator power output, specifically:

[0084] The power generation cost function of the generator in the microgrid is specifically:

[0085]

[0086] Where i = 1, 2, ..., n; n is the number of generators in the microgrid; C i (p i (t)) is the power generation cost function of the i-th generator; p i (t) is the power output of the i-th generator at time t; α i >0, β i >0 and γ i >0 is the power generation cost coefficient of the i-th generator;

[0087] The objective function of the economic dispatch problem, the supply and demand balance constraints of the generator power output, and the limit constraints of the generator power output are:

[0088]

[0089] in, is the objective function of the economic dispatch problem; is the supply and demand balance constraint of the generator power output; is the limiting constraint of the generator power output; PD is the total power demand, is the minimum power output limit of the i-th generator, is the maximum power output limit of the i-th generator.

[0090] Applying the Lagrange multiplier method to the microgrid economic dispatch problem model can obtain the Lagrange function:

[0091]

[0092] Where λ is the Lagrangian multiplier, which is also the incremental cost in the microgrid economic dispatch problem. Let the Lagrangian function be i (t) and λ take partial derivatives respectively, and the optimal incremental cost can be obtained by the Lagrange multiplier method:

[0093]

[0094] This results in optimal power output:

[0095]

[0096] In this embodiment, step S2 specifically includes the following steps:

[0097] Set the initial values ​​of the required parameters. The initial power output value of the i-th generator is p i (0), let P D is the total power demand, and the initial value of the incremental cost of the generator is calculated by the initial value of the generator power output. The initial value of the incremental cost of the i-th generator is λ i (0) = 2α i p i (0)+β i .

[0098] In this embodiment, step S3 specifically includes the following steps:

[0099] Step S31: Select the incremental cost of the generator as the consistency variable, and design a finite time consistency economic dispatch algorithm based on multi-agent consistency:

[0100]

[0101] Where i = 1, 2, ..., n; n is the number of generators in the microgrid; λ i (t) is the incremental cost of the i-th generator at time t, is the derivative of the incremental cost of the i-th generator at time t; e i (t) is the state error of the i-th generator at time t, defined as: is the kth triggering moment of the i-th generator; θ is the gain coefficient, which is used to adjust the convergence speed of the algorithm; a ij is the adjacency weight of generator i and generator j; u∈(0,1) is the ratio of two positive odd numbers;

[0102] The communication topology of a microgrid with n generators can be represented by an undirected graph G = {V, ε, A}, where V = {1, 2, ..., n}, ε ∈ V × V and Represent the node set, edge set and adjacency matrix of an undirected graph respectively. ij =(i, j) means i and j are adjacent nodes and they can exchange information with each other. If (i, j)∈ε, then a ij =1, otherwise a ij =0. In addition, L=(l ij ) n×n is the Laplace matrix of the microgrid communication topology, l ij =-a ij (i≠j),

[0103] Step S32: The event triggering conditions for designing the incremental cost of the generator according to the finite time consistency economic dispatch algorithm are specifically:

[0104]

[0105] in, is the i-th element of Lλ(t), λ(t) is the incremental cost column vector of each generator at time t, specifically λ(t) = [λ1(t), λ2(t), λ3(t), ..., λ n (t)] T ; n is the number of generators in the microgrid, L = (l ij ) n×n is the Laplace matrix of the microgrid communication topology, l ij =-a ij (i≠j), i=1, 2, ..., n; j=1, 2, ...n; σ>0 is the event threshold; inf is the lower bound.

[0106] In this embodiment, step S4 specifically includes the following steps:

[0107] When the i-th generator f i When (t)>0, the event triggering condition of the generator incremental cost is met, let The incremental cost of the generator is updated using the finite time consistency economic dispatch algorithm; the power output of the generator is calculated using the incremental cost of the generator as:

[0108]

[0109] Determine whether the incremental cost of the generator is consistent. If the incremental cost of the generator is consistent, proceed to step S5, otherwise proceed to step S4; wherein the condition for the incremental cost of the generator to be consistent is:

[0110]

[0111] in, is the average value of the incremental cost of all generators, and μ1>0 is the consistency coefficient.

[0112] In this embodiment, step S5 specifically includes the following steps:

[0113] Step S51: Introducing the incremental cost correction term q i (t) and z i (t), set the initial values ​​of the two incremental cost correction items as follows:

[0114]

[0115] Step S52: Use the finite time consistency economic dispatch algorithm to design the event triggering conditions of the incremental cost correction term, specifically:

[0116] According to the finite time consistency economic dispatch algorithm, the event trigger conditions are designed as follows:

[0117]

[0118] in, and are the i-th elements of Lq(t) and Lz(t), respectively. q(t) and z(t) are the column vectors of the incremental cost correction items of each generator at time t, specifically q(t) = [q1(t), q2(t), q3(t), ..., q n (t)] T ,z(t)=[z1(t),z2(t),z3(t),...,z n (t)] T , i=1, 2, ..., n; n is the number of generators in the microgrid, τ>0, ρ>0 is the event threshold.

[0119] In this embodiment, step S6 specifically includes the following steps:

[0120] Step S61: Use the finite time consistency economic dispatch algorithm and the event triggering condition of the incremental cost correction term to update the incremental cost correction term, use the incremental cost correction term to update the incremental cost of the generator, and calculate the power output of the generator according to the incremental cost of the generator, specifically:

[0121] The incremental cost correction term is updated by using the finite time consistent economic dispatch algorithm and the event triggering condition of the incremental cost correction term:

[0122]

[0123] Where i = 1, 2, ..., n; n is the number of generators in the microgrid; sign(·) is the sign function; q i (t) and z i (t) are two incremental cost correction items for incremental cost, and are the derivatives of the two incremental cost correction terms of the incremental cost at time t; eq i (t) and ez i (t) are the state errors of the incremental cost correction term of the i-th generator, which are defined as: ψ is the gain coefficient, which is used to adjust the convergence speed of the algorithm; v∈(0,1) and w∈(0,1) are the ratios of two positive odd numbers;

[0124] The incremental cost of updating the generator using the incremental cost modifier is:

[0125]

[0126] The incremental cost after reaching a consensus on the incremental cost of the generator; the power output of the generator is calculated based on the incremental cost of the generator:

[0127]

[0128] Step S62: Determine whether the power output of each generator exceeds the limit value. If the power output is greater than its maximum value, set the power output to its maximum value; if the power output is less than its minimum value, set the power output to its minimum value; otherwise, the power output of the generator remains unchanged. Specifically:

[0129]

[0130] When the generator power output When the generator power output is When the generator power output When the generator power output is When the generator power output When the generator power output is kept constant, p i (t) = p i (t);

[0131] Step S63: Determine whether the incremental cost correction items are consistent. If the incremental cost correction items are consistent, then output the optimal incremental cost and optimal power output of the generator. Otherwise, proceed to step S6. The conditions for the incremental cost correction items to be consistent are:

[0132]

[0133] in, and They are the incremental cost correction terms q i (t) and z i (t) is the average value; μ2>0 and μ3>0 are the consistency coefficients.

[0134] Embodiment 2:

[0135] Example 2 uses the proposed microgrid distributed economic dispatch method based on finite time event triggering to perform numerical simulation on the IEEE 14-node standard power network, with a total of 5 generators. Figure 2 It is an IEEE 14-node standard power network, and its communication topology is as follows Figure 3 shown.

[0136] The power generation cost function of each generator is Input system initial and system related parameters, total power demand P D =120MW; Table 1 shows the generator power generation cost coefficient α i , β i and γ i Table 2 shows the upper and lower limits of the generator power output; the initial values ​​of the generator power output are p1(0) = 35MW, p2(0) = 20MW, p3(0) = 25MW, p4(0) = 30MW and p5(0) = 10MW. According to the formula λ i (0) = 2α i P i (0)+β i The initial values ​​of incremental cost can be calculated as λ1(0) = 7.08$ / MW, λ2(0) = 6.53$ / MW, λ3(0) = 7.78$ / MW, λ4(0) = 7.80$ / MW and λ5(0) = 4.65$ / MW. The incremental cost correction term q i The initial values ​​of (t) are q1(0) = 0, q2(0) = 0, q3(0) = 0, q4(0) = -1.67 and q5(0) = 6.06, respectively. The incremental cost correction term z iThe initial values ​​of (t) are z1(0)=5.32, z2(0)=6.41, z3(0)=4.76, z4(0)=0 and z5(0)=0; the consistency coefficients are μ1=0.01, μ2=0.01 and μ3=0.01; the gain coefficients are θ=60, and ψ=30; event thresholds are σ=τ=ρ=0.1; design parameters are u=v=w=97 / 99. The adjacency matrix A is obtained based on the communication topology graph, and the formula l ij =-a ij (i≠j), The Laplace matrix L can be obtained, and the adjacency matrix A and the Laplace matrix L are respectively:

[0137] Table 1

[0138] Generator <![CDATA[α i ]]> <![CDATA[β i ]]> <![CDATA[γ i ]]> 1 0.094 1.22 51 2 0.078 3.41 31 3 0.105 2.53 78 4 0.082 4.02 42 5 0.074 3.17 62

[0139] Table 2

[0140]

[0141] Substitute the above parameters into the finite time consistency economic dispatch algorithm:

[0142] and trigger function In the case of the i-th generator f i When (t)>0, the event triggering condition of incremental cost is met, let The incremental cost λ of the i-th generator is updated by using the finite-time consistent economic dispatch algorithm and the event triggering condition of the generator incremental cost. i (t); incremental cost of using generator λ i (t) Calculate the power output of the generator as: Then, the incremental cost correction term is introduced, and the incremental cost correction term is updated by using the finite time consistency economic dispatch algorithm and the event triggering condition of the incremental cost correction term. The incremental cost is updated by the incremental cost correction term, and the power output of each generator is recalculated using the updated incremental cost. Determine whether the power output of each generator meets the generator power output limit constraint. If the generator power output meets the generator power output and does not exceed the limit value, the generator power output remains unchanged, otherwise the generator power output is the maximum or minimum value. Then determine whether the incremental cost correction term is consistent. If the incremental cost correction term is consistent, output the optimal incremental cost and optimal power output of the generator, otherwise continue to step S6.

[0143] Finally, the effectiveness of the present invention is verified through numerical simulation based on the given data.

[0144] Figure 4 It can be seen that at the convergence time t = 0.886S, the optimal value of incremental cost λ1(t) = λ2(t) = λ3(t) = λ4(t) = λ5(t) = 7.02$ / MW is obtained; Figure 5 It can be seen that the optimal values ​​of generator power output are p1(t)=30.88MW, p2(t)=23.18MW, p3(t)=21.40MW, p4(t)=18.33MW and p5(t)=26.05MW.

[0145] Because p4(t) = 18.33MW exceeds the minimum power output limit of generator 4, and p5(t) = 26.05MW exceeds the maximum power output limit of generator 5, after the first second, the incremental cost correction term is introduced to adjust the generator power output, and p1(t) = 32.02MW, p2(t) = 24.55MW, p3(t) = 22.43MW, p4(t) = 20.00MW and p5(t) = 21.00MW are obtained, which meets the generator power output limit constraint; Figure 4 The optimal value of the incremental cost of the generator also changes from λ1(t)=λ2(t)=λ3(t)=λ4(t)=λ5(t)=7.02$ / MW to λ1(t)=λ2(t)=λ3(t)=λ4(t)=λ5(t)=7.24$ / MW.

[0146] Figure 6 The triggering moment of each generator under the event triggering condition of incremental cost is shown.

[0147] Figure 7 Shows the total cost of electricity generation Total generation cost over time Gradually decreases and finally stabilizes at

[0148] Figure 8 The incremental cost modifier q is shown i (t) changes with time and reaches a consistent convergence.

[0149] Fig. 9 The incremental cost modifier z is shown i (t) changes with time and reaches a consistent convergence.

[0150] It should be noted that the above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A distributed economic dispatching method for microgrids based on finite time event triggering, characterized in that: The following steps are involved: Step S1: Establish a microgrid economic dispatch problem model, which includes the power generation cost function of the generator in the microgrid, the objective function of the economic dispatch problem, the supply and demand balance constraint condition of the generator power output, and the limit constraint condition of the generator power output; Step S2: setting the initial value of the output power of each generator, and calculating the initial value of the incremental cost through the initial value of the generator power output; Step S3: Select the incremental cost of the generator as the consistency variable, design a finite time consistency economic dispatch algorithm based on multi-agent consistency; design the event triggering condition of the incremental cost of the generator according to the finite time consistency economic dispatch algorithm; Step S4: Use the finite time consistency economic dispatch algorithm and the event triggering condition of the incremental cost to update the incremental cost of the generator, and calculate the power output of the generator according to the incremental cost of the generator; determine whether the incremental cost of the generator reaches a consistency, if the incremental cost of the generator reaches a consistency, proceed to step S5, otherwise continue to step S4; Step S5: introducing an incremental cost correction term and setting an initial value of the incremental cost correction term; Use the finite-time consistent economic dispatch algorithm to design the event triggering conditions of the incremental cost correction term; Step S6: Use the finite time consistency economic dispatch algorithm and the event triggering condition of the incremental cost correction term to update the incremental cost correction term, use the incremental cost correction term to update the incremental cost of the generator, and calculate the power output of the generator according to the incremental cost of the generator; determine whether the power output of each generator exceeds the limit value, if the power output is greater than its maximum value, set the power output to its maximum value; if the power output is less than its minimum value, set the power output to its minimum value, otherwise the power output of the generator remains unchanged; Then, it is determined whether the incremental cost correction term is consistent. If the incremental cost correction term is consistent, the optimal incremental cost and optimal power output of the generator are output, otherwise, the process proceeds to step S6; The step S1 specifically includes the following steps: The power generation cost function of the generator in the microgrid is specifically: Where i = 1, 2, ..., n; n is the number of generators in the microgrid; C i (p i (t)) is the power generation cost function of the i-th generator; p i (t) is the power output of the i-th generator at time t; α i >0, β i >0 and γ i >0 is the power generation cost coefficient of the i-th generator; The objective function of the economic dispatch problem, the supply and demand balance constraints of the generator power output, and the limit constraints of the generator power output are: in, is the objective function of the economic dispatch problem; is the supply and demand balance constraint of the generator power output; is the constraint condition for the generator power output; P D is the total power demand, is the minimum power output limit of the i-th generator, is the maximum power output limit of the i-th generator; The step S2 specifically includes the following steps: Set the initial output power of each generator. The initial output power of the i-th generator is p i (0), let P D is the total power demand, and the initial value of the incremental cost of the generator is calculated by the initial value of the generator power output. The initial value of the incremental cost of the i-th generator is λ i (0) = 2α i p i (0)+β i ; The step S3 specifically comprises the following steps: Step S31: Select the incremental cost of the generator as the consistency variable, and design a finite time consistency economic dispatch algorithm based on multi-agent consistency: Where i = 1, 2, ..., n; n is the number of generators in the microgrid; sign(·) is the sign function; λ i (t) is the incremental cost of the i-th generator at time t, is the derivative of the incremental cost of the i-th generator at time t; e i (t) is the state error of the i-th generator at time t, defined as: is the kth triggering moment of the i-th generator; θ is the gain coefficient, which is used to adjust the convergence speed of the algorithm; a ij is the adjacency weight of generator i and generator j; u∈(0,1) is the ratio of two positive odd numbers; Step S32: The event triggering conditions for designing the incremental cost of the generator according to the finite time consistency economic dispatch algorithm are specifically: in, is the i-th element of Lλ(t), λ(t) is the incremental cost column vector of each generator at time t, specifically λ(t)=[λ1(t),λ2(t),λ3(t),...,λ n (t)] T ; n is the number of generators in the microgrid, L = (l ij ) n×n is the Laplace matrix of the microgrid communication topology, l ij =-a ij , where i≠j; σ>0 is the event threshold; inf is the lower bound; The step S4 specifically comprises the following steps: When the i-th generator f i When (t)>0, the event triggering condition of the generator incremental cost is met, let The incremental cost of the generator is updated using the finite time consistency economic dispatch algorithm; the power output of the generator is calculated using the incremental cost of the generator as: Determine whether the incremental cost of the generator is consistent. If the incremental cost of the generator is consistent, proceed to step S5, otherwise proceed to step S4; wherein the condition for the incremental cost of the generator to be consistent is: in, is the average value of the incremental cost of all generators, and μ1>0 is the consistency coefficient.

2. A distributed economic dispatching method for microgrids based on finite time event triggering according to claim 1, characterized in that: The step S5 specifically comprises the following steps: Step S51: Introducing the incremental cost correction term q i (t) and z i (t), set the initial values ​​of the two incremental cost correction items as follows: Step S52: Use the finite time consistency economic dispatch algorithm to design the event triggering conditions of the incremental cost correction term, specifically: According to the finite time consistency economic dispatch algorithm, the event trigger conditions are designed as follows: in, and are the i-th elements of Lq(t) and Lz(t), respectively. q(t) and z(t) are the column vectors of the incremental cost correction items of each generator at time t, specifically q(t) = [q1(t), q2(t), q3(t), ..., q n (t)] T ,z(t)=[z1(t),z2(t),z3(t),...,z n (t)] T , i=1,2,...,n; n is the number of generators in the microgrid, τ>0, ρ>0 is the event threshold.

3. A microgrid distributed economic dispatching method based on finite time event triggering according to claim 2, characterized in that: The step S6 specifically comprises the following steps: Step S61: Use the finite time consistency economic dispatch algorithm and the event triggering condition of the incremental cost correction term to update the incremental cost correction term, use the incremental cost correction term to update the incremental cost of the generator, and calculate the power output of the generator according to the incremental cost of the generator, specifically: Using the finite time consistent economic dispatch algorithm and the event triggering condition of the incremental cost correction term, the incremental cost correction term is updated as follows: Where i = 1, 2, ..., n; n is the number of generators in the microgrid; sign (·) is the sign function; q i (t) and z i (t) are two incremental cost correction items for incremental cost, and are the derivatives of the two incremental cost correction terms of the incremental cost at time t; eq i (t) and ez i (t) are the state errors of the incremental cost correction term of the i-th generator, which are defined as: ψ is the gain coefficient, which is used to adjust the convergence speed of the algorithm; v∈(0,1) and w∈(0,1) are the ratios of two positive odd numbers; The incremental cost of updating the generator using the incremental cost modifier is: The incremental cost after reaching a consensus on the incremental cost of the generator; the power output of the generator is calculated based on the incremental cost of the generator: Step S62: Determine whether the power output of each generator exceeds the limit value. If the power output is greater than its maximum value, set the power output to its maximum value; if the power output is less than its minimum value, set the power output to its minimum value; otherwise, the power output of the generator remains unchanged. Specifically: When the generator power output When the generator power output is When the generator power output When the generator power output is When the generator power output When the generator power output is kept constant, p i (t) = p i (t); Step S63: Determine whether the incremental cost correction items are consistent. If the incremental cost correction items are consistent, then output the optimal incremental cost and optimal power output of the generator. Otherwise, proceed to step S6. The conditions for the incremental cost correction items to be consistent are: in, and They are the incremental cost correction terms q i (t) and z i (t) is the average value; μ2>0 and μ3>0 are the consistency coefficients.

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