Micro-grid distributed economic dispatching method based on event triggering and fixed time consistency

Abstract

The invention discloses a micro-grid distributed economic dispatching method based on event triggering fixed time consistency, and belongs to the field of energy-saving and environment-friendly economic dispatching of smart grids. The method is realized based on a multi-agent consistency theory, and specifically comprises the following steps: designing a fixed time consistency distributed economic dispatching algorithm based on the multi-agent consistency theory, designing an event triggering condition according to the algorithm, and updating the communication increment cost of a generator by using the algorithm and the event triggering condition to achieve consistency; and calculating the output power of the generator, and calculating the communication increment cost of the generator by introducing an auxiliary variable, thereby obtaining the output power of the generator, and ensuring that the output power is within the output power limit range of the generator. According to the method, fixed-time economic dispatching of the micro-grid can be realized under the condition that the generator has output power limitation, the stability and the convergence speed of the micro-grid system are improved, unnecessary communication is reduced, and network resources are saved.

Description

Technical Field

[0001] The present invention belongs to the field of smart grid energy-saving and environmental protection economic dispatching, and in particular to a distributed economic dispatching method for a microgrid based on event-triggered fixed-time consistency. Background Art

[0002] With the continuous growth of energy demand and the increasingly severe environmental problems, traditional power systems are facing huge challenges. As a new form of power system, microgrid has become a research hotspot in the global energy field with its high integration, flexible controllability, environmental protection and energy saving. Microgrid is an independent small power system composed of distributed power sources, energy storage systems, loads and monitoring and protection devices. It can operate in grid-connected and off-grid modes to provide users with reliable power supply. In the operation of microgrid, economic dispatch plays a vital role. The goal of economic dispatch is to optimize the operation strategy of each distributed power source, energy storage device and load in the microgrid to achieve the lowest system operation cost and the highest energy utilization. However, since microgrids contain a variety of distributed energy sources and loads with different characteristics, how to maintain the consistency of economic dispatch has become a key issue. Economic dispatch consistency means that the microgrid can stably achieve the economic dispatch target under the premise of meeting various constraints. In order to solve the problem of economic dispatch consistency, distributed economic dispatch algorithms have emerged. Compared with traditional centralized dispatch algorithms, distributed algorithms have better adaptability, robustness and scalability. The distributed economic dispatch algorithm decomposes the complex global optimization problem into multiple local optimization problems, so that each distributed power source, energy storage device and load can work together based on local information, thereby achieving global optimal or suboptimal economic dispatch.

[0003] In the field of microgrid control, fixed time control is an emerging control strategy that can provide a fixed convergence time for the system, regardless of the initial state of the system. The characteristic of fixed time control is that the design of its control law can ensure that the system reaches a stable state within a fixed time, which is of great significance for improving the dynamic performance and stability of the microgrid. Event-triggered control is an efficient control strategy that improves the operation efficiency of the microgrid by reducing the number of controller activations and communication burden. The core idea of ​​event-triggered control is that the controller only performs calculations and updates when the system state or output meets certain conditions. This method not only reduces the consumption of computing resources, but also reduces the pressure of network communication. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a distributed economic dispatch method for microgrids with fixed time consistency based on event triggering in view of the defects of the above-mentioned prior art.

[0005] The present invention is implemented by the following scheme: a distributed economic dispatching method for microgrids based on event-triggered fixed-time consistency, comprising the following steps:

[0006] Step S1: construct a distributed economic dispatch model for a microgrid, which includes: a power generation cost function of a generator, an objective function of economic dispatch, a supply and demand balance constraint condition of the total output power of the generator, and upper and lower limit constraints of the output power of the generator;

[0007] Step S2: setting the initial value of each generator output power and calculating the initial value of each generator incremental cost and communication incremental cost;

[0008] Step S3: Design a fixed-time consistency distributed economic scheduling algorithm based on multi-agent consistency theory, and design event triggering conditions accordingly;

[0009] Step S4: using the fixed time consistency distributed economic dispatch algorithm and event triggering conditions, updating the communication incremental cost of the generator, and calculating the output power of the generator according to the communication incremental cost of the generator; judging whether the communication incremental cost of the generator reaches consistency, if it reaches consistency, executing step S5, otherwise continuing to execute step S4;

[0010] Step S5: introducing an auxiliary variable of incremental cost and setting an initial value for it;

[0011] Step S6: Use the fixed-time consistency distributed economic dispatch algorithm to update the auxiliary variables of the incremental cost, use the updated auxiliary variables to correct the incremental cost of the generator and obtain the incremental communication cost of the generator, and calculate the output power of the generator based on this; determine whether the output power of the generator meets the upper and lower limit constraints, if the output power of the generator exceeds its maximum value, set the output power to its maximum value, if the output power of the generator is lower than its minimum value, set the output power to its minimum value, otherwise the output power of the generator remains unchanged;

[0012] Step S7: Determine whether the auxiliary variables of the incremental cost have reached consistency. If they have reached consistency, output the incremental cost of the generator, the communication incremental cost and the output power. Otherwise, return to step S6 to update the auxiliary variables again.

[0013] Furthermore, the step S1 constructs a distributed economic dispatch model for the microgrid, which includes: a power generation cost function of the generator, an objective function of economic dispatch, a supply and demand balance constraint condition of the total output power of the generator, and upper and lower limit constraints of the output power of the generator, 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 output power 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 economic dispatch, the supply and demand balance constraints of the total output power of the generator, and the upper and lower limit constraints of the generator output power are as follows:

[0018]

[0019] in, is the objective function of economic dispatch; is the supply and demand balance constraint of the total output power of the generator; is the upper and lower limit constraints of the generator output power; P D is the total power demand, is the minimum output power of the i-th generator, is the maximum output power of the i-th generator.

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

[0021] The initial value of the output power of the i-th generator is set to p i (0), where Through the formula λ i (0) = 2α i p i (0)+β i The initial value of the incremental cost of each generator is calculated as λ i (0); let the initial value of the incremental communication cost of each generator be

[0022] Furthermore, step S3 designs a fixed-time consistency distributed economic scheduling algorithm based on multi-agent consistency theory, and designs event triggering conditions accordingly, specifically:

[0023] Step S31: Design a fixed-time consistency distributed economic scheduling algorithm based on multi-agent consistency theory, specifically:

[0024]

[0025] 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; is the jth generator at time The incremental communication cost; is the i-th generator at time incremental costs; The kth triggering time for updating the incremental cost of the i-th generator; a ij is the adjacency matrix A of the generator communication topology = (a ij )∈R n×n Elements; c 1 、c 2 and c 3 is a normal constant; p∈(0,1) and q∈(1,∞) are the ratios of two positive odd integers;

[0026] Define the measurement error e of the i-th generator at time t i (t) is:

[0027]

[0028] in, Update the k+1th triggering time of the incremental cost for the i-th generator;

[0029] Therefore, the fixed-time consistency distributed economic scheduling algorithm can be rewritten as:

[0030] Step S32: The event triggering conditions for updating the incremental cost of the generator are designed according to the fixed time consistency distributed economic dispatch algorithm, which are specifically:

[0031]

[0032] Among them, the trigger function c 4 is a positive constant; inf is the lower bound, Update the k+1th triggering time of the incremental cost for the i-th generator.

[0033] Furthermore, the step S4 specifically includes the following steps:

[0034] Use the fixed-time consistency distributed economic dispatch algorithm to update the incremental cost of the generator; determine whether the event triggering condition is met, when the g of the i-th generator i When (t)>0, the event triggering condition is met, let Assign the incremental cost of the generator at this moment to the incremental communication cost of the generator: When the g of the i-th generatori When (t)≤0, the event triggering condition is not met, and the communication incremental cost of the generator remains unchanged; the output power of the generator is calculated based on the communication incremental cost of the generator;

[0035] The output power of the i-th generator is calculated using the incremental communication cost:

[0036]

[0037] It is determined whether the communication incremental cost of the generator reaches consistency. If it reaches consistency, it proceeds to step S5, otherwise it returns to step S4 to update the communication incremental cost again. The condition for the communication incremental cost of the i-th generator to reach consistency is:

[0038]

[0039] in, is the average value of the incremental communication cost of all generators, a 1 >0 is the incremental cost convergence coefficient. After the communication incremental cost of the generators reaches consistency, the communication incremental cost of all generators is λ * .

[0040] Furthermore, the step S5 is specifically as follows:

[0041] The auxiliary variable b of the incremental cost introduced by the i-th generator i (t) and d i (t), and set their initial values ​​as follows:

[0042]

[0043] Among them, p i (t) is the output power of the ith generator after the communication incremental cost of the generator reaches consistency; hour, when hour, when hour,

[0044] Furthermore, the step S6 is specifically as follows:

[0045] Step S61: Use the fixed time consistency distributed economic dispatch algorithm to update the auxiliary variables of the incremental cost, use the updated auxiliary variables to correct the incremental cost of the generator and obtain the incremental communication cost of the generator, and calculate the output power of the generator based on this, specifically:

[0046] The auxiliary variables for updating the incremental cost using the fixed time consistency distributed economic scheduling algorithm are:

[0047]

[0048] Where i = 1, 2, ..., n; n is the number of generators in the microgrid; b i (t) and d i (t) are two auxiliary variables of the incremental cost of the i-th generator; and are the derivatives of the two auxiliary variables of the incremental cost of the i-th generator at time t; c 5 , c 6 and c 7 is a normal constant; p∈(0,1) and q∈(1,∞) are the ratios of two positive odd integers;

[0049] Correct the incremental cost of the generator using the updated auxiliary variables:

[0050]

[0051] is the incremental cost after the communication incremental cost of the i-th generator reaches consistency; let The output power of the generator is calculated based on the incremental communication cost of the generator:

[0052]

[0053] Step S62: Determine whether the generator output power meets the upper and lower limit constraints. If the generator output power exceeds its maximum value, set the output power to its maximum value. If the generator output power is lower than its minimum value, set the output power to its minimum value. Otherwise, the generator output power remains unchanged. Specifically:

[0054]

[0055] When the generator output power When When the generator output power When When the generator output power When the generator output power remains unchanged, p i (t) = p i (t).

[0056] Furthermore, the step S7 is specifically as follows:

[0057] It is determined whether the auxiliary variables of the incremental cost have reached consistency. If they have reached consistency, the incremental cost of the generator, the incremental cost of communication and the output power are output. Otherwise, it returns to step S6 to update the auxiliary variables again. The condition for the auxiliary variables of the incremental cost to reach consistency is:

[0058]

[0059] in, The incremental cost auxiliary variables b for all generators are i (t) and d i (t); i = 1, 2, ..., n; n is the number of generators in the microgrid; a 2 >0,a 3 >0 is the convergence coefficient.

[0060] The present invention provides a distributed economic dispatch method for microgrids based on event-triggered fixed-time consistency. Compared with the prior art, the present invention has the following beneficial effects:

[0061] 1. The distributed economic dispatching method for microgrids proposed in the present invention is completely distributed. Compared with the traditional centralized dispatching method, the distributed economic dispatching method has higher reliability and scalability. In microgrids, distributed economic dispatching can more effectively cope with various challenges and maintain the stable operation of the system.

[0062] 2. In the distributed economic dispatch of microgrids, the present invention adopts an event trigger mechanism to effectively reduce the communication burden between generators. Each distributed generator communicates with its neighbors through event trigger control and exchanges power information, thereby reducing unnecessary communication and saving network resources.

[0063] 3. The fixed-time consistency distributed economic dispatch algorithm proposed in this invention can improve the stability and convergence speed of the microgrid system under complex topologies, and combine event-triggered control to reduce communication overhead and energy consumption. Fixed-time economic dispatch of microgrids can be realized when the generator has output power limitations. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 This is a flow chart of the distributed economic dispatch method of microgrid based on event-triggered fixed-time consistency of the present invention;

[0065] Figure 2 The IEEE 30-node standard power network of the present invention;

[0066] Figure 3 The communication topology diagram of each generator of the present invention;

[0067] Figure 4 is the incremental cost λ of each generator of the present invention i (t) Changes over time;

[0068] Figure 5 The incremental cost of each generator communication in the present invention is Plot of changes over time;

[0069] Figure 6 is the output power p of each generator of the present invention i (t) time-varying graph;

[0070] Figure 7 The total output power of the generator of the present invention is and the total power demand P D Plots of changes over time;

[0071] Figure 8 It is a diagram of triggering time of each generator event of the present invention;

[0072] Fig. 9 is the measurement error e of each generator of the present invention i (t) and Plot of changes over time;

[0073] Fig.10 is the auxiliary variable b of the present invention i (t) Changes over time;

[0074] Fig.11 is the auxiliary variable d of the present invention i (t) Variation with time. DETAILED DESCRIPTION

[0075] 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.

[0076] Embodiment 1:

[0077] The process of the distributed economic dispatch method of microgrid based on event-triggered fixed time consistency provided in this embodiment is as follows: Figure 1 As shown, the specific steps include:

[0078] Step S1: construct a distributed economic dispatch model for a microgrid, which includes: a power generation cost function of a generator, an objective function of economic dispatch, a supply and demand balance constraint condition of the total output power of the generator, and upper and lower limit constraints of the output power of the generator;

[0079] Step S2: setting the initial value of each generator output power and calculating the initial value of each generator incremental cost and communication incremental cost;

[0080] Step S3: Design a fixed-time consistency distributed economic scheduling algorithm based on multi-agent consistency theory, and design event triggering conditions accordingly;

[0081] Step S4: using the fixed time consistency distributed economic dispatch algorithm and event triggering conditions, updating the communication incremental cost of the generator, and calculating the output power of the generator according to the communication incremental cost of the generator; judging whether the communication incremental cost of the generator reaches consistency, if it reaches consistency, executing step S5, otherwise continuing to execute step S4;

[0082] Step S5: introducing an auxiliary variable of incremental cost and setting an initial value for it;

[0083] Step S6: Use the fixed-time consistency distributed economic dispatch algorithm to update the auxiliary variables of the incremental cost, use the updated auxiliary variables to correct the incremental cost of the generator and obtain the incremental communication cost of the generator, and calculate the output power of the generator based on this; determine whether the output power of the generator meets the upper and lower limit constraints, if the output power of the generator exceeds its maximum value, set the output power to its maximum value, if the output power of the generator is lower than its minimum value, set the output power to its minimum value, otherwise the output power of the generator remains unchanged;

[0084] Step S7: Determine whether the auxiliary variables of the incremental cost have reached consistency. If they have reached consistency, output the incremental cost of the generator, the communication incremental cost and the output power. Otherwise, return to step S6 to update the auxiliary variables again.

[0085] In this embodiment, the step S1 constructs a distributed economic dispatch model of a microgrid, which includes: a power generation cost function of a generator, an objective function of economic dispatch, a supply and demand balance constraint condition of the total output power of the generator, and upper and lower limit constraints of the output power of the generator, specifically:

[0086] The power generation cost function of the generator in the microgrid is specifically:

[0087]

[0088] 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 output power 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;

[0089] The objective function of economic dispatch, the supply and demand balance constraints of the total output power of the generator, and the upper and lower limit constraints of the generator output power are as follows:

[0090]

[0091] in, is the objective function of economic dispatch; is the supply and demand balance constraint of the total output power of the generator; is the upper and lower limit constraints of the generator output power; P D is the total power demand, is the minimum output power of the i-th generator, is the maximum output power of the i-th generator.

[0092] In this embodiment, step S2 specifically includes the following steps:

[0093] The initial value of the output power of the i-th generator is set to p i (0), where Through the formula λ i (0) = 2α i p i (0)+β i The initial value of the incremental cost of each generator is calculated as λ i (0); let the initial value of the incremental communication cost of each generator be

[0094] In this embodiment, step S3 designs a fixed-time consistency distributed economic scheduling algorithm based on multi-agent consistency theory, and designs event triggering conditions accordingly, specifically:

[0095] Step S31: Design a fixed-time consistency distributed economic scheduling algorithm based on multi-agent consistency theory, specifically:

[0096]

[0097] 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; is the jth generator at time The incremental communication cost; is the i-th generator at time incremental costs; The kth triggering time for updating the incremental cost of the i-th generator; a ij is the adjacency matrix A of the generator communication topology = (a ij )∈R n×n Elements; c 1 、c 2 and c 3 is a normal constant; p∈(0,1) and q∈(1,∞) are the ratios of two positive odd integers;

[0098] Define the measurement error e of the i-th generator at time t i (t) is:

[0099]

[0101] in, Update the k+1th triggering time of the incremental cost for the i-th generator;

[0102] Therefore, the fixed-time consistency distributed economic scheduling algorithm can be rewritten as:

[0103] 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 the undirected graph respectively; e 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;

[0104] Step S32: The event triggering conditions for updating the incremental cost of the generator are designed according to the fixed time consistency distributed economic dispatch algorithm, which are specifically:

[0105]

[0106] Among them, the trigger function c 4 is a positive constant; inf is the lower bound, Update the k+1th triggering time of the incremental cost for the i-th generator.

[0107] In this embodiment, the step S4 uses the fixed time consistency distributed economic dispatch algorithm and event triggering conditions to update the communication incremental cost of the generator, and calculate the output power of the generator according to the communication incremental cost of the generator; determine whether the communication incremental cost of the generator reaches consistency, if it reaches consistency, then execute step S5, otherwise continue to execute step S4, specifically:

[0108] Use the fixed-time consistency distributed economic dispatch algorithm to update the incremental cost of the generator; determine whether the event triggering condition is met, when the g of the i-th generator i When (t)>0, the event triggering condition is met, let Assign the incremental cost of the generator at this moment to the incremental communication cost of the generator: When the g of the i-th generator i When (t)≤0, the event triggering condition is not met, and the communication incremental cost of the generator remains unchanged; the output power of the generator is calculated based on the communication incremental cost of the generator;

[0109] The output power of the i-th generator is calculated using the incremental communication cost:

[0110]

[0111] It is determined whether the communication incremental cost of the generator reaches consistency. If it reaches consistency, it proceeds to step S5, otherwise it returns to step S4 to update the communication incremental cost again. The condition for the communication incremental cost of the i-th generator to reach consistency is:

[0112]

[0113] in, is the average value of the incremental communication cost of all generators, a 1 >0 is the incremental cost convergence coefficient. After the communication incremental cost of the generators reaches consistency, the communication incremental cost of all generators is λ * .

[0114] In this embodiment, step S5 specifically includes the following steps:

[0115] The auxiliary variable b of the incremental cost introduced by the i-th generator i (t) and d i (t), and set their initial values ​​as follows:

[0116]

[0117] Among them, p i (t) is the output power of the ith generator after the communication incremental cost of the generator reaches consistency; hour, when hour, when hour,

[0118] In this embodiment, step S6 specifically includes the following steps:

[0119] Step S61: Use the fixed time consistency distributed economic dispatch algorithm to update the auxiliary variables of the incremental cost, use the updated auxiliary variables to correct the incremental cost of the generator and obtain the incremental communication cost of the generator, and calculate the output power of the generator based on this, specifically:

[0120] The auxiliary variables for updating the incremental cost using the fixed time consistency distributed economic scheduling algorithm are:

[0121]

[0122] Where i = 1, 2, ..., n; n is the number of generators in the microgrid; b i (t) and d i (t) are two auxiliary variables of the incremental cost of the i-th generator; and are the derivatives of the two auxiliary variables of the incremental cost of the i-th generator at time t; c 5 , c 6 and c 7 is a normal constant; p∈(0,1) and q∈(1,∞) are the ratios of two positive odd integers;

[0123] Correct the incremental cost of the generator using the updated auxiliary variables:

[0124]

[0125] is the incremental cost after the communication incremental cost of the i-th generator reaches consistency; let The output power of the generator is calculated based on the incremental communication cost of the generator:

[0126]

[0127] Step S62: Determine whether the generator output power meets the upper and lower limit constraints. If the generator output power exceeds its maximum value, set the output power to its maximum value. If the generator output power is lower than its minimum value, set the output power to its minimum value. Otherwise, the generator output power remains unchanged. Specifically:

[0128]

[0129] When the generator output power When When the generator output power When When the generator output power When the generator output power remains unchanged, p i (t) = p i (t).

[0130] In this embodiment, step S7 specifically includes the following steps:

[0131] It is determined whether the auxiliary variables of the incremental cost have reached consistency. If they have reached consistency, the incremental cost of the generator, the incremental cost of communication and the output power are output. Otherwise, it returns to step S6 to update the auxiliary variables again. The condition for the auxiliary variables of the incremental cost to reach consistency is:

[0132]

[0133] in, The incremental cost auxiliary variables b for all generators are i (t) and d i (t); i = 1, 2, ..., n; n is the number of generators in the microgrid; a 2 >0,a 3 >0 is the convergence coefficient.

[0134] Embodiment 2:

[0135] Example 2 uses the proposed event-triggered fixed-time consistency microgrid distributed economic dispatch method to perform numerical simulation on the IEEE 30-node standard power network, with a total of 6 generators. Figure 2 It is an IEEE 30-node standard power network, and its communication topology is as follows Figure 3 shown.

[0136] The power generation cost function of the generator in the microgrid is C i (p i (t)) = α i p i 2 (t)+β i p i (t)+γ i , Table 1 shows the power generation cost coefficient α i , β i , γ i and the upper and lower limits of the generator output power; input the initial value and system related parameters, the total power demand P D =160MW, the initial value of generator output power p 1 (0) = 10MW, p 2 (0) = 15MW, p 3 (0) = 20MW, p 4 (0) = 40MW, p 5 (0) = 45MW and p 6 (0) = 30MW, according to the calculation formula λ i (0) = 2α i p i (0)+β i , we can get the initial value of incremental cost λ 1 (0) = 3.60$ / MW, λ 2(0) = 5.60$ / MW, λ 3 (0) = 4.82$ / MW, λ 4 (0) = 9.20$ / MW, λ 5 (0) = 8.40$ / MW and λ 6 (0) = 5.88$ / MW, and the initial value of the incremental communication cost of each generator is The initial value of the auxiliary variable is b 1 (0) = 0, b 2 (0) = -0.10, b 3 (0) = 0, b 4 (0) = 0, b 5 (0) = 0, b 6 (0) = 15.34, d 1 (0) = 6.25, d 2 (0) = 0, d 3 (0) = 8.62, d 4 (0) = 7.69, d 5 (0) = 8.33 and d 6 (0) = 0; the system parameters are set to c 1 =0.1, c 2 =0.15, c 3 =39, c 4 =5, c 5 =1, c 6 =17, c 7 =70, p = 97 / 99 and q = 7 / 5; the convergence coefficient is set to a 1 =a 2 =a 3 =0.01; According to the communication topology diagram, the adjacency matrix A is:

[0137]

[0138] Table 1

[0139]

[0140] Bring the above parameters into the fixed time consistency distributed economic scheduling algorithm and trigger function When the g of the i-th generator i When (t)>0, the event triggering condition is met, let Assign the incremental cost of the generator at this moment to the incremental communication cost of the generator: When the g of the i-th generatori When (t)≤0, the event triggering condition is not met, and the communication incremental cost of the generator remains unchanged; the output power of the i-th generator is calculated using the communication incremental cost: Then, the auxiliary variable of the incremental cost of the generator is introduced, and the auxiliary variable is calculated through the fixed time consistency distributed economic dispatch algorithm. The incremental cost is corrected with the auxiliary variable and the communication incremental cost of the generator is obtained. Based on this, the output power of the generator is calculated. Determine whether the generator output power meets the upper and lower limit constraints. If the generator output power exceeds its maximum value, set the output power to its maximum value. If the generator output power is lower than its minimum value, set the output power to its minimum value. Otherwise, the generator output power remains unchanged. Then determine whether the auxiliary variables of the incremental cost are consistent. If they are consistent, output the incremental cost of the generator, the communication incremental cost and the output power. Otherwise, return to step S6 to update the auxiliary variables again.

[0142] Finally, the effectiveness of the present invention is verified through numerical simulation based on the given data.

[0143] Figure 4 is the incremental cost λ of each generator i (t) Changes over time; Figure 5 Incremental cost for each generator communication A graph showing changes over time. Figure 4 and Figure 5 It can be seen that at the convergence time t = 1.63s, the optimal values ​​of incremental cost and communication incremental cost are Figure 6 is the output power p of each generator i (t) Variation with time. Figure 6 It can be seen that the optimal value of the generator output power p 1 (t) = 26.85MW, p 2 (t)=19.97MW,p 3 (t)=32.73MW,p 4 (t)=17.66MW,p 5 (t) = 27.47MW and p 6 (t) = 35.48MW. Because p 2 (t) = 19.97MW and p 6 (t) = 35.48 MW, which exceeds the output power limit of generator 2 and generator 6. After 2.5 seconds, the auxiliary variable is introduced to correct the generator output power, and p is obtained. 1 (t)=29.38MW,p 2 (t)=22.86MW,p 3 (t)=36.21MW,p 4 (t)=20.77MW,p5 (t) = 30.83MW and p 6 (t) = 20.00MW, which meets the generator output power limit constraint; Figure 4 and Figure 5 The optimal values ​​of medium incremental cost and communication incremental cost also changed from 6.29$ / MW to 6.70$ / MW.

[0144] Figure 7 is the total output power of the generator and the total power demand P D Plots of changes over time; Figure 8 It is the triggering time diagram of each generator event; Fig. 9 Measure the error e for each generator i (t) and Plot of changes over time; Fig.10 is the auxiliary variable b i (t) Changes over time; Fig.11 is the auxiliary variable d i (t) Variation with time.

[0145] in, Figure 7 Shows the total generator output power Total power demand P D =160MW, meeting the generator supply and demand balance constraint; Fig.10 Shows the auxiliary variable b i (t) changes over time and reaches consistency convergence; Fig.11 Shows the auxiliary variable d i (t) changes with time and reaches consistent convergence.

[0146] 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 dispatch method for microgrids based on event-triggered fixed-time consistency, characterized in that: The following steps are involved: Step S1: construct a distributed economic dispatch model for a microgrid, which includes: a power generation cost function of a generator, an objective function of economic dispatch, a supply and demand balance constraint condition of the total output power of the generator, and upper and lower limit constraints of the output power of the generator; Step S2: setting the initial value of each generator output power and calculating the initial value of each generator incremental cost and communication incremental cost; Step S3: Design a fixed-time consistency distributed economic scheduling algorithm based on multi-agent consistency theory, and design event triggering conditions accordingly; Step S4: using the fixed time consistency distributed economic dispatch algorithm and event triggering conditions, updating the communication incremental cost of the generator, and calculating the output power of the generator according to the communication incremental cost of the generator; judging whether the communication incremental cost of the generator reaches consistency, if it reaches consistency, executing step S5, otherwise continuing to execute step S4; Step S5: introducing an auxiliary variable of incremental cost and setting an initial value for it; Step S6: Use the fixed-time consistency distributed economic dispatch algorithm to update the auxiliary variables of the incremental cost, use the updated auxiliary variables to correct the incremental cost of the generator and obtain the incremental communication cost of the generator, and calculate the output power of the generator based on this; determine whether the output power of the generator meets the upper and lower limit constraints, if the output power of the generator exceeds its maximum value, set the output power to its maximum value, if the output power of the generator is lower than its minimum value, set the output power to its minimum value, otherwise the output power of the generator remains unchanged; Step S7: Determine whether the auxiliary variables of the incremental cost have reached consistency. If they have reached consistency, output the incremental cost of the generator, the communication incremental cost and the output power. Otherwise, return to step S6 to update the auxiliary variables again.

2. The method for distributed economic dispatching of microgrids based on event-triggered fixed-time consistency according to claim 1 is characterized in that: 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 output power 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 economic dispatch, the supply and demand balance constraints of the total output power of the generator, and the upper and lower limit constraints of the generator output power are as follows: in, is the objective function of economic dispatch; is the supply and demand balance constraint of the total output power of the generator; is the upper and lower limit constraints of the generator output power; P D is the total power demand, is the minimum output power of the i-th generator, is the maximum output power of the i-th generator.

3. The distributed economic dispatching method of microgrid based on event-triggered fixed time consistency according to claim 2 is characterized in that: The step S2 specifically includes the following steps: The initial value of the output power of the i-th generator is set to p i (0), where Through the formula λ i (0) = 2α i p i (0)+β i The initial value of the incremental cost of each generator is calculated as λ i (0); let the initial value of the incremental communication cost of each generator be 4. The method for distributed economic dispatching of microgrids based on event-triggered fixed-time consistency according to claim 3 is characterized in that: The step S3 specifically comprises the following steps: Step S31: Design a fixed-time consistency distributed economic scheduling algorithm based on multi-agent consistency theory, specifically: 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; is the jth generator at time The incremental communication cost; is the i-th generator at time incremental costs; The kth triggering time for updating the incremental cost of the i-th generator; a ij is the adjacency matrix A of the generator communication topology = (a ij )∈R n×n elements; c1, c2 and c3 are positive constants; p∈(0,1) and q∈(1,∞) are the ratios of two positive odd numbers; Define the measurement error e of the i-th generator at time t i (t) is: in, Update the k+1th triggering time of the incremental cost for the i-th generator; Therefore, the fixed-time consistency distributed economic scheduling algorithm can be rewritten as: Step S32: The event triggering conditions for updating the incremental cost of the generator are designed according to the fixed time consistency distributed economic dispatch algorithm, which are specifically: Among them, the trigger function c4 is a positive constant; inf is the lower bound, Update the k+1th triggering time of the incremental cost for the i-th generator.

5. The method for distributed economic dispatching of microgrids based on event-triggered fixed-time consistency according to claim 4 is characterized in that: The step S4 specifically comprises the following steps: Use the fixed-time consistency distributed economic dispatch algorithm to update the incremental cost of the generator; determine whether the event triggering condition is met, when the g of the i-th generator i When (t)>0, the event triggering condition is met, let Assign the incremental cost of the generator at this moment to the incremental communication cost of the generator: When the g of the i-th generator i When (t)≤0, the event triggering condition is not met, and the communication incremental cost of the generator remains unchanged; the output power of the generator is calculated based on the communication incremental cost of the generator; The output power of the i-th generator is calculated using the incremental communication cost: It is determined whether the communication incremental cost of the generator reaches consistency. If it reaches consistency, it proceeds to step S5, otherwise it returns to step S4 to update the communication incremental cost again. The condition for the communication incremental cost of the i-th generator to reach consistency is: in, is the average value of the incremental communication cost of all generators, a1>0 is the incremental cost convergence coefficient, and after the incremental communication cost of the generators reaches consistency, the incremental communication cost of all generators is λ * .

6. The method for distributed economic dispatching of microgrids based on event-triggered fixed-time consistency according to claim 5 is characterized in that: The step S5 specifically comprises the following steps: The auxiliary variable b of the incremental cost introduced by the i-th generator i (t) and d i (t), and set their initial values ​​as follows: Among them, p i (t) is the output power of the ith generator after the communication incremental cost of the generator reaches consistency; hour, when hour, when hour, 7. The method for distributed economic dispatching of microgrids based on event-triggered fixed-time consistency according to claim 6 is characterized in that: The step S6 specifically comprises the following steps: Step S61: Use the fixed time consistency distributed economic dispatch algorithm to update the auxiliary variables of the incremental cost, use the updated auxiliary variables to correct the incremental cost of the generator and obtain the incremental communication cost of the generator, and calculate the output power of the generator based on this, specifically: The auxiliary variables for updating the incremental cost using the fixed time consistency distributed economic scheduling algorithm are: Where i = 1, 2, ..., n; n is the number of generators in the microgrid; b i (t) and d i (t) are two auxiliary variables of the incremental cost of the i-th generator; and are the derivatives of the two auxiliary variables of the incremental cost of the i-th generator at time t; c5, c6 and c7 are positive constants; p∈(0,1) and q∈(1,∞) are the ratios of two positive odd numbers; Correct the incremental cost of the generator using the updated auxiliary variables: is the incremental cost after the communication incremental cost of the i-th generator reaches consistency; let The output power of the generator is calculated based on the incremental communication cost of the generator: Step S62: Determine whether the generator output power meets the upper and lower limit constraints. If the generator output power exceeds its maximum value, set the output power to its maximum value. If the generator output power is lower than its minimum value, set the output power to its minimum value. Otherwise, the generator output power remains unchanged. Specifically: When the generator output power When When the generator output power When When the generator output power When the generator output power remains unchanged, p i (t) = p i (t).

8. The method for distributed economic dispatching of microgrids based on event-triggered fixed-time consistency according to claim 7 is characterized in that: The step S7 specifically includes the following steps: It is determined whether the auxiliary variables of the incremental cost have reached consistency. If they have reached consistency, the incremental cost of the generator, the incremental cost of communication and the output power are output. Otherwise, it returns to step S6 to update the auxiliary variables again. The condition for the auxiliary variables of the incremental cost to reach consistency is: in, The incremental cost auxiliary variables b for all generators are i (t) and d i (t); i = 1, 2, ..., n; n is the number of generators in the microgrid; a2>0, a3>0 are the convergence coefficients.

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