A coordinated operation control method for AC / DC hybrid microgrid based on intelligent algorithm

Abstract

The present invention discloses a coordinated operation control method of an AC / DC hybrid microgrid based on an intelligent algorithm. First, for the operation control of the AC / DC hybrid microgrid, based on the control theory of multiple agents, global information is obtained through communication between adjacent agents, and a distributed multi-agent collaborative control framework without a centralized controller is established; then, based on the topological structure of the AC / DC bidirectional converter, the parameters are corrected for consistency of the distributed control output through a droop control method for the bidirectional converter, and the power of the bidirectional converter is adjusted; finally, according to the distributed control algorithm, the reactive power correction value of the AC distributed power source and the current correction value of the DC distributed power source are obtained, and a distributed secondary control strategy for the AC / DC hybrid microgrid is proposed to realize the voltage and frequency recovery of all communication units, and the coordinated control of reactive power sharing and DC current proportional sharing. The control method of the present invention can meet the reliable switching requirements of the system load and the distributed power source, and enhance the flexibility and reliability of the system.

Description

Technical Field

[0001] The present invention relates to the field of AC / DC hybrid microgrid control optimization, and in particular to an AC / DC hybrid microgrid coordinated operation control method based on an intelligent algorithm. Background Art

[0002] Distributed power sources represented by new energy sources have characteristics such as intermittency, volatility, and uncertainty. The interactive impact between distributed power sources and the large power grid is more prominent. Under high penetration rates, it will have a huge impact on the entire large power grid, affecting the power supply quality and stability of the large power grid.

[0003] In order to give full play to the advantages of AC / DC microgrids, it is proposed to build an AC / DC hybrid microgrid. By controlling the bidirectional converter, energy conversion and complementarity between the two microgrids are realized. When the hybrid microgrid is operating normally, the bidirectional converter can automatically adjust according to different working conditions to realize bidirectional power transmission. This not only enhances the power supply capacity of the microgrid, but also greatly improves its ability to respond to emergencies. At the same time, the design of this hybrid microgrid also effectively reduces the circulating current generated by distributed power sources, which can significantly improve the energy utilization and overall absorption capacity. In this microgrid structure, the droop control strategy is the main control technology. However, the droop control scheme lacks an effective communication mechanism, which makes it difficult to accurately realize these expected functions during actual operation. At the same time, the line impedance and output impedance of the distributed power supply equipment will fluctuate with changes in environmental factors. This non-ideal impedance characteristic further aggravates the difficulty of reactive power sharing and causes deviations in the DC side load distribution. Faced with these challenges, the optimization control of distributed hybrid microgrids requires innovative solutions.

[0004] Intelligent agents have the characteristics of autonomy, initiative and coordination. The introduction of intelligent agents can enable the control system of microgrids to maintain a high degree of autonomy and flexibility in a more complex and changeable environment. The core intelligent agent concentrates and processes the interactive information of each distributed intelligent agent, thereby realizing efficient regulation of the overall operation of the microgrid. According to the intelligent algorithm of multi-agents, it can meet the distributed control system. By ensuring the consistency of the control output of each part, the control parameters of the system can be effectively corrected, and then the voltage and frequency recovery of all communication units and the DC current and reactive power can be achieved. The purpose of balancing the power distribution between units is achieved, thereby improving the flexibility and reliability of the entire system. At the same time, it can also reduce the unnecessary communication volume between the intelligent agents, thereby reducing the complexity and cost of the entire system operation. Summary of the invention

[0005] The problem to be solved by the present invention is to provide a coordinated operation control method for an AC / DC hybrid microgrid based on an intelligent algorithm, and to study a distributed control method for a microgrid with AC / DC interaction for the operation control of the AC / DC hybrid microgrid, so that it can meet the reliable switching requirements of the system load and distributed power supply, and enhance the flexibility and reliability of the system.

[0006] The present invention adopts the following technical solution: a method for coordinated operation control of an AC / DC hybrid microgrid based on an intelligent algorithm, comprising the following steps:

[0007] S1. For the operation control of AC / DC hybrid microgrid, based on the control theory of multi-agent, global information is obtained through communication between adjacent agents, and a distributed multi-agent collaborative control framework without a centralized controller is established;

[0008] S2. Under the framework of multi-agent collaborative control, based on the topological structure of AC / DC bidirectional converter, a droop control method for bidirectional converter is proposed. The power regulation of bidirectional converter is realized by making consistent corrections to the parameters of distributed control output.

[0009] S3. On the basis of droop control, according to the distributed control algorithm, the reactive power correction value of the AC distributed power source and the current correction value of the DC distributed power source are obtained, and a distributed secondary control strategy for the AC / DC hybrid microgrid is proposed to achieve the purpose of voltage and frequency recovery of all communication units, reactive power balancing and DC current proportional balancing coordinated control.

[0010] Furthermore, in step S1, based on the control theory of multi-agents, global information is obtained through communication between adjacent agents, and a distributed multi-agent collaborative control framework without a centralized controller is established. The control process is as follows:

[0011] Step 1.1, use the consistency of distributed control output to correct the control parameters of the system, and its iterative equation is as follows:

[0012] D i k+1 =D i k +ΔD i k

[0013] Where i is the i-th distributed power source; D is the control variable; D k , D k+1 ) are the results of the variable D at the kth and k+1th distributed iterations respectively; ΔD i k is the modified value of variable D at the kth distributed iteration, and its expression is:

[0014]

[0015]

[0016] In the formula, a, b, l are control coefficients, 0 <l<1,a> 0, b≥0; ε ij is the communication coefficient, ε ij ≥0; N i is the number of power sources adjacent to distributed power source i.

[0017] Step 1.2, to achieve the optimal communication performance between agents, that is, the communication coefficient ε ij It can be dynamically adjusted as the distributed control system changes, and its expression is:

[0018]

[0019] Where λ is the control factor, which can achieve different control effects, 0<λ<1; i and j are the i-th and j-th distributed power sources respectively; z i 、z j are the numbers of remaining distributed power sources when the i-th and j-th distributed power sources communicate respectively.

[0020] Furthermore, in step S2, under the framework of multi-agent collaborative control, based on the topological structure of the AC / DC bidirectional converter, a droop control method for the bidirectional converter is proposed, and the power regulation of the bidirectional converter is realized by performing consistency correction of the distributed control output of the parameters. The specific steps are as follows:

[0021] Step 2.1, based on the control method of AC distributed power inverter and DC distributed power converter, the droop control method of AC distributed power inverter is:

[0022] (1) Droop control current control equation:

[0023]

[0024] In the formula, K sj K is the PI controller parameter sj =k mj +k nj / s,j=1,2;i p 、i q are the actual values ​​of active and reactive current respectively; i p_ref 、i q_ref are the reference values ​​of active and reactive current respectively; u p 、u q are the actual values ​​of active and reactive voltage respectively; L is the inductance; ω is the inverter output angular velocity; ωL is the inverter inductive reactance;

[0025] (2) Droop control power control equation:

[0026]

[0027] In the formula, K sj =k mj +k nj / s,j=3,4;P g , Q g are the actual output power values ​​of distributed power sources; R f is the Pf droop coefficient, R U is the QU droop coefficient;

[0028] Step 2.2, DC droop control technology performs voltage / current droop control on the chopper circuit of the microgrid to ensure the voltage / current stability of the system under disturbance conditions and strengthen the stable control of voltage / current in the microgrid;

[0029] The DC droop control method using the voltage-current droop relationship is as follows:

[0030] P′=(R(U ref -U0)-I0)K s

[0031] The DC droop control method using the power-current droop relationship is as follows:

[0032] P′=(R(P ref -P0)+(U ref -U0)-I0)K s

[0033] In the formula, K s is the PI controller parameter K s =k m +k n / s; R is the DC droop control coefficient; P0, U0, I0 are the actual values ​​of output power, voltage and current respectively, P ref , U ref are the reference values ​​of power and voltage under droop control in rated operation state respectively; P′ is the final modulation waveform of droop control;

[0034] Step 2.3, in order to ensure the smooth operation of the bidirectional converter and the controllability of the transmitted power, a droop control method similar to the PQ control is proposed. The power regulation of the bidirectional converter is achieved by making consistency corrections to the parameters of the distributed control output.

[0035] Among them, the reference value P is obtained by the following formula ref , Q ref :

[0036]

[0037]

[0038] Its control equation is as follows:

[0039]

[0040] Where, Δf = f0-f; ΔU = U0-U; R P is the active power-frequency droop coefficient; R Q is the reactive power-voltage droop coefficient; P0 and Q0 are the actual values ​​of active power and reactive power output of the bidirectional converter respectively; f is the frequency measurement value, f0 is the rated operating frequency, U is the effective value of the line voltage; U0 is the rated value of the output line voltage.

[0041] Further, in step S3, based on the droop control, according to the distributed control algorithm, the reactive power correction value of the AC distributed power source and the current correction value of the DC distributed power source are obtained, and a distributed secondary control strategy of the AC / DC hybrid microgrid is proposed to achieve the purpose of voltage and frequency recovery of all communication units, reactive power sharing and DC current proportional sharing coordinated control. The specific control steps are as follows:

[0042] Step 3.1, for AC distributed power supply, its control equation is as follows:

[0043]

[0044] In the formula, R f , R U is the droop coefficient; Δf and ΔU are the frequency and voltage compensation values ​​respectively; ΔP0 and ΔQ0 are the differences between the reference value and the actual value of active power and reactive power respectively.

[0045] Among them, ΔQ is the reactive power correction value of distributed power source obtained according to the distributed control algorithm, which realizes the reactive power sharing of distributed power source, and its expression is:

[0046]

[0047] Step 3.2, for DC distributed power control, based on DC droop control, the DC distributed power is controlled in a distributed secondary manner to achieve voltage recovery and current proportional distribution of the DC microgrid. The control equation is:

[0048]

[0049] Where R is the droop coefficient; U and I are the actual values ​​of voltage and current respectively, subscript 0 is the voltage and current under rated operating conditions; ΔU is the voltage compensation value; and I′ is the control modulation signal.

[0050] Among them, Δi is the DC distributed power supply current correction value obtained according to the distributed control algorithm, which controls the DC distributed power supply load ratio, and its expression is:

[0051]

[0052] In the AC / DC hybrid microgrid, each communication unit realizes effective control of the output power of distributed power sources through efficient data interaction. Through intelligent algorithms, it ensures timely restoration of voltage and frequency stability under various conditions, while achieving equal distribution of reactive power and proportional distribution of DC current, thereby maintaining the efficiency and reliability of the entire system.

[0053] The technical solution of the present invention also provides: an electronic device, comprising:

[0054] one or more processors;

[0055] a storage device having one or more programs stored thereon;

[0056] When the one or more programs are executed by the one or more processors, the one or more processors implement any of the above-mentioned AC / DC hybrid microgrid coordinated operation control methods based on intelligent algorithms.

[0057] The technical solution of the present invention also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps in any of the above-mentioned AC / DC hybrid microgrid coordinated operation control methods based on intelligent algorithms are implemented.

[0058] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0059] 1. The present invention realizes mutual communication and coordinated control among distributed power sources in the system by applying control theory based on multi-agent system in microgrid system, making the system more flexible and stable, that is, improving the elasticity of the system and reducing the number of communications between agents.

[0060] 2. Aiming at the stability problem of operation control of AC / DC hybrid microgrid system, the present invention proposes a distributed control strategy for microgrid that takes into account AC / DC power interaction, so as to meet the function of reactive power balancing of distributed power sources when the system load fluctuates, and improve the flexibility and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a flow chart of the steps of the AC / DC hybrid microgrid coordinated operation control method of the present invention;

[0062] Figure 2 This is a distributed control diagram of an AC / DC hybrid microgrid of the present invention;

[0063] Figure 3 The bidirectional converter topology structure of the present invention;

[0064] Figure 4 This is a simulation diagram of an AC / DC hybrid microgrid according to an embodiment of the present invention;

[0065] Figure 5 The reactive power of the AC microgrid in the embodiment of the present invention;

[0066] Figure 6 It is a distributed consistency iteration of an embodiment of the present invention;

[0067] Figure 7 is the active power of the AC microgrid in the embodiment of the present invention;

[0068] Figure 8 The reactive power of the AC microgrid in the embodiment of the present invention;

[0069] Fig. 9 It is the active power and reactive power of the bidirectional converter according to the embodiment of the present invention. DETAILED DESCRIPTION

[0070] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0071] In one embodiment of the present invention, a distributed hybrid microgrid optimization control method based on multi-agent control theory is provided. Figure 1 As shown, the steps include:

[0072] Step S1. The present invention is based on the control theory of multi-agents, obtains global information through communication between adjacent agents, establishes a distributed multi-agent collaborative control framework without a centralized controller, and performs control.

[0073] In this embodiment, a distributed multi-agent collaborative control framework without a centralized controller is used. Figure 2 As shown, each distributed power source is regarded as an intelligent agent, where AC distributed power sources 1, 2, ..., n are connected to AC loads and DC distributed power sources 1, 2, ..., n are connected to DC loads. Intelligent agents 1, 2, ..., n obtain the output power Q1, Q2, ..., Q2 of adjacent AC distributed power sources 1, 2, ..., n respectively. n And the output current i1,i2,...,i n, and exchange data with adjacent units; the bidirectional converter is regarded as intelligent agent n+1, and the AC and DC distributed power sources exchange information through intelligent agent n+1 to obtain the output power Q n .

[0074] The specific control process is as follows:

[0075] Step 1.1, use the consistency of distributed control output to correct the control parameters of the system. The iterative equation is as follows:

[0076] D i k+1 =D i k +ΔD i k

[0077] Where i is the i-th distributed power source; D is the control variable; D k , D k+1 are the results of the variable D at the kth and k+1th distributed iterations respectively; ΔD i k is the modified value of variable D at the kth distributed iteration, expressed as follows:

[0078]

[0079]

[0080] In the formula, a, b, l are control coefficients (0 <l<1,a> 0, b≥0); ε ij is the communication coefficient (ε ij ≥0);

[0081] Step 1.2, to achieve the optimal communication performance between agents, that is, the communication coefficient ε ij It can be dynamically adjusted as the distributed control system changes, and its expression is:

[0082]

[0083] Where λ is the control factor, which can achieve different control effects, 0<λ<1; i and j are the i-th and j-th distributed power sources respectively; z i (z j ) is the number of remaining distributed power sources when the i(j)th distributed power source communicates.

[0084] Step S2: Under the framework of multi-agent collaborative control, based on the topological structure of the AC / DC bidirectional converter, a droop control method for the bidirectional converter is proposed, and the power regulation of the bidirectional converter is achieved by making consistency corrections to the parameters of the distributed control output.

[0085] In this embodiment, based on the topology of the AC / DC bidirectional converter, such as Figure 3 As shown, the AC-DC side grid can perform power interaction between AC and DC through a bidirectional converter. The bidirectional converter includes a main circuit and a control circuit. The DC-AC in the main circuit is a three-phase full-bridge inverter, L is the filter inductor, and R is the parasitic resistance of the filter inductor. The control circuit is based on the DC side voltage U dc And AC output voltage U ac The bidirectional converter outputs a control signal by setting a bidirectional interactive control strategy. After the gate controller and SPWM modulation, the bidirectional converter can operate in the rectification state or the inverter state, realizing bidirectional power transmission on the AC and DC sides.

[0086] The power regulation of the bidirectional converter is as follows:

[0087] Step 2.1, based on the control method of AC distributed power inverter and DC distributed power converter, the droop control method of AC distributed power inverter is:

[0088] (1) Droop control current control equation:

[0089]

[0090] In the formula, K sj is the PI controller parameter (j=1, 2); i p (i q ) is the actual value of active (reactive) current; i p_ref (i q_ref ) is the reference value of active (reactive) current; u p (u q ) is the actual value of active (reactive) voltage.

[0091] (2) Droop control power control equation:

[0092]

[0093] In the formula, K sj is the PI controller parameter (j=3, 4); P g , Q g is the actual value of the distributed power output power; R f is the Pf droop coefficient, R U is the QU droop coefficient;

[0094] In particular, in this embodiment, K sj is (k mj +k nj / s).

[0095] Step 2.2, the DC droop control technology performs voltage / current droop regulation on the chopper circuit of the microgrid to ensure the voltage / current stability of the system under disturbance conditions and strengthen the stable control of the voltage / current in the microgrid.

[0096] The DC droop control method using the voltage-current droop relationship is as follows:

[0097] P′=(R(U ref -U0)-I0)K s

[0098] The DC droop control method using the power-current droop relationship is as follows:

[0099] P′=(R(P ref -P0)+(U ref -U0)-I0)K s

[0100] In the formula, K s is (k m +k n / s), PI controller parameters; R is the DC droop control coefficient; P0, U0, I0 are the actual values ​​of output power, voltage and current respectively, P ref , U ref are the reference values ​​of power, voltage and current under droop control in rated operating state; P′ is the final modulation waveform of droop control.

[0101] Step 2.3, in order to ensure the smooth operation of the bidirectional converter and the controllability of the transmitted power, a droop control method similar to the PQ control is proposed. The power regulation of the bidirectional converter is achieved by making consistency corrections to the parameters of the distributed control output.

[0102] Among them, the reference value P can be obtained by the formula ref , Q ref :

[0103]

[0104]

[0105] Its control equation is as follows:

[0106]

[0107] Where, Δf is f0-f; ΔU is U0-U; R P is the active power-frequency droop coefficient; R Qis the reactive power-voltage droop coefficient; P0 and Q0 are the actual values ​​of active power and reactive power output by the bidirectional converter; f is the frequency measurement value, f0 is the rated operating frequency, U is the effective value of the line voltage; U0 is the rated value of the output line voltage;

[0108] Particularly, in this embodiment, f0 is 50 Hz and U0 is 380 V.

[0109] Step S3, based on the droop control, according to the distributed control algorithm, obtain the reactive power correction value of the AC distributed power source and the current correction value of the DC distributed power source, and propose a distributed secondary control strategy for the AC / DC hybrid microgrid to achieve the purpose of voltage and frequency recovery of all communication units, reactive power sharing and DC current proportional sharing coordinated control. The specific control steps are as follows:

[0110] Step 3.1, for AC distributed power supply, its control equation is as follows:

[0111]

[0112] In the formula, R f , R U is the droop coefficient; Δf and ΔU are the frequency and voltage compensation values; ΔP0 and ΔQ0 are the differences between the reference value and the actual value of active power and reactive power.

[0113] Among them, ΔQ is the reactive power correction value of distributed power source obtained according to the distributed control algorithm, which realizes the reactive power sharing of distributed power source, and its expression is:

[0114]

[0115] Step 3.2, for DC distributed power control, based on DC droop control, the DC distributed power is controlled in a distributed secondary manner to achieve voltage recovery and current proportional distribution of the DC microgrid. The control equation is as follows:

[0116]

[0117] In the formula, K s is (k m +k n / s), PI controller parameters; R is the droop coefficient; U and I are the actual values ​​of voltage and current (subscript 0 is the voltage and current under rated operating conditions); ΔU is the voltage compensation value; I′ is the control modulation signal.

[0118] Among them, Δi is the DC distributed power supply current correction value obtained according to the distributed control algorithm, which controls the DC distributed power supply load ratio, and its expression is:

[0119]

[0120] In the AC / DC hybrid microgrid, each communication unit realizes effective control of the output power of distributed power sources through efficient data interaction. Through intelligent algorithms, it ensures timely restoration of voltage and frequency stability under various conditions, while achieving equal distribution of reactive power and proportional distribution of DC current, thereby maintaining the efficiency and reliability of the entire system.

[0121] In this embodiment, the effectiveness and adaptability of the proposed control strategy are verified through simulation examples of typical scenarios.

[0122] First, the overall model of the AC / DC microgrid is built using PSCAD / EMTDC simulation software, in which the AC / DC microgrids are located on the left and right sides of the model and connected by converters. The total active load of the AC microgrid is 95kW, the reactive load is 20kVar, and the total resistance of the DC microgrid is 33Ω.

[0123] The above intelligent algorithm is programmed by MATLAB and co-simulated with PSCAD. The algorithm is imported into the droop control strategy of PSCAD to realize the distributed optimization control of AC / DC hybrid microgrid. The simulation model is as follows: Figure 4 shown.

[0124] When the load of the system remains unchanged, the rated voltage (380V) and rated frequency (50Hz) of the AC / DC microgrid remain unchanged. The distributed power sources in the system all use droop control. According to the relationship between frequency and active power, the impedance of the line itself does not affect the output of active power of the power source in the microgrid, and the active power of each distributed power source is evenly distributed. However, the impedance of each line is different, which makes the voltage and reactive power of the output node of the distributed power source in the microgrid system different, and reactive power equalization cannot be achieved. Figure 5 and Figure 6 shown.

[0125] When t=3s, the microgrid system starts to use distributed algorithms to perform secondary control on the system in order to achieve the purpose of consistent control strategy. Distributed power sources communicate with each other through the connection of multiple intelligent agents, and data exchange begins between each distributed power source. The entire hybrid microgrid starts to perform equal-division iteration through mutual coordinated control.

[0126] When t=4.3s, the reactive power output by each distributed power source in the system communicates with each other. The distributed power sources with more reactive output are transmitted to the distributed power sources with less reactive output through the action of multi-agents. The reactive power of the system's distributed power sources is 18.4kvar, so as to achieve reactive power equalization of the entire system and improve the stability of the hybrid microgrid system.

[0127] During normal operation, the AC and DC microgrids each bear the load of their respective local power grids. There is no power interaction between the two, and their AC and DC inverters have no active or reactive output.

[0128] In actual power systems, the load is changing all the time. When the system transitions from one steady state to another, the output of AC and DC distributed power sources will change.

[0129] At t=4.9s, the load carried by the AC microgrid is increased. As the system load changes, the distributed consistency control strategy is started simultaneously.

[0130] When t<4.9s, there is no AC or DC power transmission between the two microgrids, both can meet the load power supply needs, and the bidirectional converter of the hybrid microgrid has no power output.

[0131] At t = 4.9s, a new working condition appeared. The load on the AC side increased, the system power supply was not timely, and overload occurred. The simulation diagram of the active and reactive power of each power supply in the AC microgrid when the load on the AC side increased and overload occurred, as shown in the figure below: Figure 7 and Figure 8 shown.

[0132] After an overload occurs, each distributed power source in the system increases its output active and reactive power. At this time, since the load on the AC side increases while the DC side remains unchanged, the output power of the AC microgrid decreases, and the bidirectional converter starts. The DC microgrid transfers part of its power to the AC microgrid through the power transfer function of the converter to provide power support. Fig. 9 This is a simulation diagram of the active and reactive power output of the bidirectional converter.

[0133] After obtaining power support from the DC side, both active and reactive power decreased. At t=7s, distributed consistency control was performed again through multi-agents to achieve equal distribution of reactive power. The distributed power sources of the entire system cooperated with each other to increase power, and power was transmitted to the AC microgrid through the AC / DC bidirectional converter. The reactive power equalization effect was significantly enhanced, and the proportional distribution of loads in the system was achieved.

[0134] The simulation results show that, from the simulation scenario of the load change on the AC side, the control of the hybrid microgrid based on the control theory method of multi-agent can effectively enhance the stability of the system and deal with the disturbance problem of the microgrid. The control method proposed in the embodiment can effectively control the bidirectional converter to be in the operating state of zero power interaction and active and reactive interaction, and can realize the mutual transfer of power between the AC side and the DC side. When various working conditions change, the AC and DC power flows bidirectionally through the action of the converter, thereby improving the stability of the system.

[0135] In summary, the present invention realizes mutual communication and collaborative control between each distributed power source in the system through the application of control theory based on multi-agent system in microgrid system, making the system more flexible and stable, that is, improving the elasticity of the system and reducing the number of communications between agents; in view of the stability problem of operation control of AC / DC hybrid microgrid system, a microgrid distributed control strategy considering AC / DC power interaction is proposed to meet the role of reactive power balancing of distributed power sources when the system load fluctuates, improve the flexibility of the system, and provide a new idea for solving the problem of mutual collaborative control of new distribution systems.

[0136] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A coordinated operation control method for AC / DC hybrid microgrid based on intelligent algorithm, characterized in that: The steps include: S1. For the operation control of AC / DC hybrid microgrid, based on the control theory of multi-agent, global information is obtained through communication between adjacent agents, and a distributed multi-agent collaborative control framework without a centralized controller is established; S2. Under the framework of multi-agent collaborative control, based on the topological structure of the AC / DC bidirectional converter, the parameters are corrected for consistency of the distributed control output through the droop control method for the bidirectional converter to achieve power regulation of the bidirectional converter. The specific steps are as follows: Step 2.1: Improve the control method of AC distributed power inverter and DC distributed power converter. In the droop control method of AC distributed power inverter, the droop control current is controlled, and the equation is: In the formula, K sj is the PI controller parameter, j = 1, 2; i p 、i q are the actual values ​​of active and reactive current respectively; i p_ref 、i q_ref are the reference values ​​of active and reactive current respectively; u p 、u q are the actual values ​​of active and reactive voltage respectively; L is the inductance; ω is the inverter output angular velocity; ωL is the inverter inductive reactance; Droop control power control, the equation is: In the formula, K sj is the PI controller parameter, j = 3, 4; P g , Q g are the actual output power values ​​of distributed power sources; R f is the Pf droop coefficient, R U is the QU droop coefficient; f is the frequency measurement value, f0 is the rated operating frequency; U is the effective value of the line voltage, U0 is the rated value of the output line voltage; Step 2.2, perform DC droop control, and control the voltage / current droop of the chopper circuit of the microgrid to ensure the voltage / current stability of the system under disturbance conditions; DC droop control using voltage-current droop relationship is performed as follows: P′=(R(U ref -U0)-I0)K s (3) The DC droop control using the power-current droop relationship is as follows: P′=(R(P ref -P0)+(U ref -U0)-I0)K s (4) In the formula, K s is the PI controller parameter; R is the DC droop control coefficient; P0, U0, I0 are the actual values ​​of output power, voltage and current respectively, P ref , U ref They are the reference values ​​of power and voltage under droop control in rated operation state respectively; P′ is the final modulation waveform of droop control; Step 2.3: Through the droop control method similar to PQ control, the parameters are corrected for the consistency of the distributed control output, the power of the bidirectional converter is adjusted, and the stable operation of the bidirectional converter and the controllable transmission power are ensured. The reference value P ref , Q ref The control equation is as follows: Where, Δf = f0-f, ΔU = U0-U; R P is the active power-frequency droop coefficient, R Q is the reactive power-voltage droop coefficient; P0 and Q0 are the actual values ​​of active power and reactive power output by the bidirectional converter respectively; The reference value P is obtained by the following formula ref , Q ref : Among them, P i k , P j k are the actual active values ​​output by the i-th and j-th distributed generation in the k-th distributed iteration, Q i k , Q j k are the actual reactive power values ​​output by the i-th and j-th distributed generation in the k-th distributed iteration respectively; S3. On the basis of droop control, according to the distributed control algorithm, the reactive power correction value of the AC distributed power source and the current correction value of the DC distributed power source are obtained, and a distributed secondary control strategy for the AC / DC hybrid microgrid is proposed to restore the voltage and frequency of all communication units, and coordinate the reactive power sharing and DC current proportional sharing.

2. The AC / DC hybrid microgrid coordinated operation control method based on intelligent algorithm according to claim 1 is characterized in that: Step S1 establishes a distributed multi-agent collaborative control framework without a centralized controller. The control process is as follows: Step 1.1: Use the consistency of distributed control output to correct the control parameters of the system. The iterative equation is: D i k+1 =D i k +ΔD i k (8) Where i is the i-th distributed power source; D is the control variable; D i k , D i k+1 are the results of the kth and k+1th distributed iterations of the control variable D of the i-th distributed generation; ΔD i k is the correction value of the control variable D of the i-th distributed generation at the k-th distributed iteration, and the expression is: In the formula, a, b, l are control coefficients, 0 <l<1、a> 0, b≥0; ε ij is the communication coefficient, ε ij ≥0; N i is the number of power sources adjacent to distributed power source i; Step 1.2: To achieve optimal communication performance between agents, the communication coefficient ε ij Dynamic adjustment is performed as the distributed control system changes. The expression is: when Where λ is the control factor used to achieve different control effects, 0<λ<1; i and j are the i-th and j-th distributed power sources; z i 、z j are the numbers of remaining distributed power sources when the i-th and j-th distributed power sources communicate respectively.

3. The AC / DC hybrid microgrid coordinated operation control method based on intelligent algorithm according to claim 1 is characterized in that: In step S3, according to the distributed control algorithm, the reactive power correction value of the AC distributed power source and the current correction value of the DC distributed power source are obtained, and a distributed secondary control strategy of the AC / DC hybrid microgrid is proposed to restore the voltage and frequency of all communication units, and coordinate the reactive power sharing and DC current proportional sharing. The control steps are as follows: Step 3.1: For AC distributed power supply, the control equation is: In the formula, R f , R U is the droop coefficient; Δf and ΔU are the frequency and voltage compensation values ​​respectively; ΔP0 and ΔQ0 are the differences between the reference value and the actual value of active power and reactive power respectively; ΔQ is the reactive power correction value of distributed generation obtained by the distributed control algorithm; Step 3.2: For DC distributed power control, based on DC droop control, distributed secondary control is performed on the DC distributed power to achieve voltage recovery and current proportional distribution of the DC microgrid. The control equation is: Where R is the droop coefficient; U and I are the actual values ​​of voltage and current, U0 and I0 are the voltage and current under rated operating conditions; ΔU is the voltage compensation value; I′ is the control modulation signal; Δi is the DC distributed power supply current correction value obtained by the distributed control algorithm.

4. The AC / DC hybrid microgrid coordinated operation control method based on intelligent algorithm according to claim 3 is characterized in that: In step S3.1, the reactive power correction value ΔQ of the distributed power source obtained according to the distributed control algorithm is used for reactive power sharing of the distributed power source, and the expression is: in, is the reactive power correction value of the distributed generation output at the kth distributed iteration.

5. The AC / DC hybrid microgrid coordinated operation control method based on intelligent algorithm according to claim 4 is characterized in that: In step S3.2, the DC distributed power supply current correction value Δi obtained according to the distributed control algorithm is used to control the DC distributed power supply load proportion distribution, and the expression is: in, is the distributed power supply current correction value output at the kth distributed iteration.

6. The AC / DC hybrid microgrid coordinated operation control method based on intelligent algorithm according to claim 1 is characterized in that: In an AC / DC hybrid microgrid, n distributed power sources are regarded as n intelligent agents. Each intelligent agent obtains the output power of adjacent AC distributed power sources and the output current of DC distributed power sources respectively, and exchanges data with adjacent units. The bidirectional converter is regarded as intelligent agent n+1. The AC / DC distributed power sources interact with each other through intelligent agent n+1, obtain and control the output power of the distributed power sources, restore the stability of the output voltage and frequency under various conditions, and at the same time, divide the reactive power equally and the DC current proportionally, so as to perform reliable switching between loads and distributed power sources.

7. An electronic device, characterized in that: include: one or more processors; a storage device having one or more programs stored thereon; When the one or more programs are executed by the one or more processors, the one or more processors implement the coordinated operation control method of the AC / DC hybrid microgrid based on an intelligent algorithm as described in any one of claims 1 to 6.

8. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the coordinated operation control method of an AC / DC hybrid microgrid based on an intelligent algorithm as described in any one of claims 1 to 6 is implemented.

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