CN101510686B - Coordinated control system of microgrid based on multi-agent technology - Google Patents

Abstract

The invention relates to a micro-grid coordination control system based on multi-agent technology, pertaining to the information technology field, wherein an element agent module independently controls the operation of bottom elements in the micro-grid, realizing direct control on a distributive power source, power generation, power-reserving elements and some loads; a micro-grid agent module operates in accordance with the internal dispatching of the micro-gird and manages the agents; task division and shared resource allocation among agents are solved by communication and coordination between the micro-grid agent module and an upper grid agent module, and the upper grid agent module takes charge of the coordination and dispatching in the electric market and among agents and makes the important decisions by integrating information of the micro-grid agents. A certain amount of data communication among the agent modules are kept for better ensuring rationality for decisions made by each agent. The structure and the communication method fit the complex and flexible characteristics of micro-grid distribution. The coordination control system can promote the safe and steady operation of the micro-grid as well as the generating efficiency.

Description

Coordinated control system of microgrid based on multi-agent technology

technical field

The invention relates to a system in the field of information technology, in particular to a micro-grid coordination control system based on multi-agent technology.

Background technique

Microgrid is a system composed of load and micro power supply, which can provide electric energy and heat energy at the same time; its internal power supply is mainly responsible for energy conversion by power electronic devices and provides necessary control; its performance compared to the external large power grid It is a single controlled unit and can meet the user's requirements for power quality and power supply security at the same time. It includes the following main features: 1) It includes distributed power sources such as photovoltaics and wind power. 2) Equipped with an energy management system, through the control of a large number of power electronic devices, problems such as power flow and protection can be solved. 3) It is required that it can be connected to the large power grid, and can be disconnected from the main grid when the grid fails or needs to be operated independently. At the same time, it is necessary to effectively control various distributed power sources. Due to its distributed characteristics, massive control data, and flexible and changeable control methods, it is difficult to achieve flexible and effective scheduling in the previous centralized control method that was uniformly judged and dispatched by the dispatching center. Therefore, by distributing control rights to each microgrid component, the distributed coordinated control method in which each component changes its operating state according to the scheduling of the microgrid will effectively solve these problems. Under this trend, a system based on distributed control - multi-agent system is proposed. The multi-agent system has good autonomy and inspiration, and its purpose is to divide the large complex system into small, inter-communicating and coordinating systems, which are easy to manage. Its advantages are: 1) It can control the operation of components without interference and can reason and plan through the knowledge system and the external environment to solve various problems in its own field; 2) It can communicate with other entities And coordinate and cooperate to solve complex problems; 3) Have the ability to distribute and quickly deal with complex problems.

After searching the literature of the prior art, it was found that R.H.Lasseter et al. in Proceedings of 2002 IEEE Power Engineering Society Winter Meeting, VOL.1: 305-308 (2002 IEEE Power Engineering Society Winter Conference Proceedings, Volume 1: 305-308) Published Microgrids (microgrid), this article puts forward the concept of microgrid, specifically the framework structure of microgrid, its shortcoming is that it does not propose a flexible coordination control structure based on multi-agent system. Proceedings based control for Microgrids published by Aris L. Dimeas et al. in Proceedings of 2007 IEEE Power Engineering Society General Meeting, 2007: 1-5 (2007 IEEE Power Engineering Society Conference Proceedings, 1-5), This paper proposes the basic framework of multi-agent system control, but does not propose specific communication mechanisms, multi-agent coordination control, etc., and does not discuss it in depth. The Chinese invention patent (application number: 200710152493.0) proposes a microgrid connection line control system. This method is suitable for the basic control of the microgrid, and the coordination is relatively lacking. Therefore, it is of great practical significance to study a control system framework and its method that can coordinately control the microgrid.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a micro-grid coordination control system based on multi-agent technology, so as to improve the operation stability of the micro-grid and the efficiency of the power grid, and adapt to the requirements of the micro-grid.

The present invention is realized through the following technical solutions, and the present invention includes: an element agent module, a micro-grid agent module, and an upper-level power grid agent module. The component agent module, the microgrid agent module, and the upper-level grid agent module are divided into three layers for coordinated control, among which: the element agent module independently controls the operation of each underlying component in the microgrid, and realizes direct distributed energy control, power generation control, and energy storage components. control and control of some loads; the microgrid agent module manages the agent for the internal scheduling operation of the microgrid, including accepting component agent information, and providing corresponding control strategies according to the microgrid operating status and adjustment strategy; the superior grid agent The module is responsible for the coordination and scheduling of the power market and various agents, and makes major decisions based on the microgrid agent information. The microgrid agent module and the upper-level grid agent module solve the task division and shared resource allocation between agents through communication coordination. ; Each agent module also maintains data communication to better ensure the rationality of their respective decisions. This structure and communication method adapts to the distributed, complex and flexible characteristics of the microgrid.

During operation, the element agent module controls each element in the microgrid, and provides the operating status of the controlled elements to the microgrid agent module. After receiving the information from the element agent module, the microgrid agent module provides control strategies for the element agent module. The component proxy module changes the running state of the corresponding control component by itself after receiving the control information. The micro-grid agent module provides the operating status of each micro-grid to the upper-level grid agent module, and the upper-level grid agent module performs preliminary data processing and then transmits it to the estimation link through a unified format of the information processing system. At the same time, each microgrid agent module also directly submits the operating status of its own grid to the estimation link, and the estimation link submits the control strategy of each microgrid to the corresponding microgrid agent module after model prediction. After the microgrid agent module changes the operating state of the microgrid, the upper level grid agent module and the microgrid agent module submit the operating state to the estimation link again for further adjustment. Through continuous coordinated control, the micro-grid coordinated control system based on multi-agent technology will enable the micro-grid to provide appropriate power to the upper-level grid while ensuring the safe, reliable, and economical operation of its own grid.

The element agent module includes a first grid-connected agent module, a first data processing module, a first data transmission module, a first data storage module, and an internal control module, wherein: the first grid-connected agent module is responsible for controlling the effect of the elements on the microgrid It mainly receives the grid connection and disconnection information provided by the first data transmission module or the microgrid agent module, and takes the grid connection command transmitted by the microgrid agent module as the high priority, and the first data The grid connection command transmitted by the transmission module is low priority for grid connection. The first data processing module and the first data storage module are responsible for processing and storing the data of the proxied components, so as to process and update the running status of the components in time, and the first data transmission module is responsible for transmitting the running status information of the components to The microgrid proxy module receives commands from the microgrid proxy module. The internal control module is a specific component control program. It mainly inputs the corresponding control program to control the operation of different components to ensure that the components controlled by a single component agent can run safely and stably. It only receives the commands transmitted by the first data processing module. At the same time, the component agent module has anti-interference ability to the outside world, and can make corresponding adjustments to small changes in the outside world, and this process does not require the intervention of the microgrid agent module, so that the effective operation of the components can be guaranteed.

The microgrid agent module includes a second grid-connected agent module, a second data processing module, a second data transmission module, and a second data storage module, wherein: the second grid-connected agent module is responsible for the parallelization of the controlled microgrid to the upper-level grid Network and disconnection function It mainly receives the grid connection and disconnection information provided by the second data transmission module or the upper-level power grid agent module, and the grid connection command transmitted by the upper-level grid agent module is a high priority, and the second data transmission module transmits The grid connection command is low priority for grid connection. The second data processing module is responsible for processing the information provided by the component agent module when the network is disconnected, and provides corresponding control strategies for the corresponding component agent through the second data transmission module according to the result of data processing; The module will increase the connection with the upper-level power grid agent module, receive the data transmitted between the component agent module and the communication module in the upper-level power grid agent module, and provide corresponding control strategies for the corresponding component agent through the second data transmission module according to the results of data processing , and at the same time communicate the operating status of the microgrid to the upper-level grid agent module through the second data transmission module for further coordinated control. The second data storage module stores the results of the second data processing module for other agent modules to query. The micro-grid agent module is mainly used to optimize the operation of the micro-grid or just as a simple regional load scheduling. Its purpose is to make the control of the micro-grid more flexible and reduce various losses in the micro-grid. The microgrid agent module is mainly responsible for the control of more than one agent, that is, to coordinate and control several agents it manages.

The above power grid agent module mainly provides corresponding strategies for the operation of the medium voltage network and the low voltage network, without specific grid connection control and operation control, including the third data processing module, the third data transmission module, the third data The storage module is mainly responsible for the overall dispatch and strategy analysis of the power network in each region. The third data processing module is responsible for comprehensively processing the data transmitted by multiple micro-grid agent modules. Under the condition of ensuring the stability of the power grid, the policy scheduling is carried out according to the initial given control strategy, and the micro-grid is controlled by the data transmission module. The grid agent module issues instructions. The third data storage module is responsible for storing the data transmitted by each micro-grid agent module and the control strategy data processed by the third data processing module, for query by the micro-grid agent module and the administrator.

In the coordinated control of the whole multi-agent system of the present invention, since the connection between the modules is mainly by communication, communication is an important link therein. In the present invention, the following two communication methods are mainly adopted:

1) Combination of federal system communication and broadcast communication (direct information transmission)

First, each agent module dynamically joins the federation and accepts the services provided by the federation. These services include: accepting the addition of agent modules; recording the ability, task and level of joining agent modules; providing communication services; providing responses to requests made by agents, etc.

Second, use the broadcast mechanism to send the message to each agent module or a group. Usually the sender needs to specify a unique address, and only agents that meet this condition can read the message.

Since the information between agents in this way is exchanged directly, there is no buffering in execution. In order to ensure that other agents can obtain the corresponding data, it will also be supplemented by the blackboard system.

2) Blackboard system (indirect information transmission)

The blackboard is a global database for agents to write messages, publish results, and obtain information. It is divided into several levels according to the researched agent problems. Agents working at the same level can access the corresponding blackboard level and adjacent levels. All necessary Information can be posted on the blackboard for retrieval by all agents.

In this way, each agent can obtain enough data to guarantee its own or cooperative control with other agents.

The system of the present invention solves the control structure framework and specific communication coordination problems of the microgrid by proposing a multi-agent system-based framework structure, a communication mechanism, a coordinated control platform, and the specific control functions of each component agent in the microgrid. By proposing a coordinated control strategy within the microgrid and with the superior grid, the coordinated control of the microgrid is further optimized. Generally speaking, the hierarchical control of the power network containing the microgrid is realized, thereby reducing the risk of a single distributed power supply operation and improving the reliability of the entire power grid for long-distance travel; reducing the transmission network loss caused by long-distance, Improve the efficiency of the grid.

Description of drawings

Fig. 1 is a structural block diagram of the present invention.

Fig. 2 is a schematic block diagram of the present invention.

Fig. 3 is a schematic diagram of component proxy functions in the present invention.

Fig. 4 is a schematic diagram of a microgrid framework according to an embodiment of the present invention.

Fig. 5 is a flowchart of microgrid coordination control according to an embodiment of the present invention.

Fig. 6 is a curve diagram of photovoltaic power generation MPPT and load according to an embodiment of the present invention.

Fig. 7 is a diagram of the simulation result of the embodiment of the present invention.

Fig. 8 is a curve diagram of the node voltage of the microgrid according to the embodiment of the present invention.

Fig. 9 is a current diagram of a storage battery according to an embodiment of the present invention.

Detailed ways

The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings: this embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following the described embodiment.

As shown in Figure 1, the component agent module, the microgrid agent module, and the upper-level grid agent module are divided into three layers for coordinated control. Each underlying component (including generators, loads, etc.) in the microgrid is controlled and operated by an independent component agent module. At the same time, the micro-grid agent module is set to manage these agents, such as: accept component agent information, and provide corresponding control strategies according to the micro-grid operating status and adjustment strategies. The microgrid agent module and the superior grid agent module solve the task division and the allocation of shared resources between agents through communication and coordination. The upper-level power grid agent module is responsible for the coordination and scheduling of the power market and various agents, and makes major decisions based on the information of micro-grid agents. A certain amount of data communication is also maintained between different agent modules to better ensure the rationality of their respective decisions. This structure and communication method adapts to the distributed, complex and flexible characteristics of the microgrid.

As shown in Figure 2, the element agent module controls each element in the microgrid, and provides the operating status of the controlled elements to the microgrid agent module. After the microgrid agent module receives the information from the element agent module, it provides control strategies for the element agent. The component proxy module changes the running state of the corresponding control component by itself after receiving the control information. The micro-grid agent module provides the operating status of each micro-grid to the upper-level grid agent module, and the upper-level grid agent module performs preliminary data processing and then transmits it to the estimation link through a unified format of the information processing system. At the same time, each microgrid agent module also directly submits the operating status of its own grid to the estimation link, and the estimation link submits the control strategy of each microgrid to the corresponding microgrid agent module after model prediction. After the microgrid agent module changes the operating state of the microgrid, the upper level grid agent module and the microgrid agent module submit the operating state to the estimation link again for further adjustment. Through continuous coordinated control, the micro-grid coordinated control system based on multi-agent technology will enable the micro-grid to provide appropriate power to the upper-level grid while ensuring the safe, reliable, and economical operation of its own grid.

As shown in FIG. 3 , the component agent module includes five modules: a first grid-connected agent module, a first data processing module, a first data transmission module, a first data storage module, and an internal control module. Its main function is to realize direct distributed energy control, power generation control, energy storage element control and some load control. The first grid-connected agent module is mainly responsible for the grid-connected and disconnected functions of the controlled components to the microgrid. The first data processing module, the first data transmission module and the first data storage module are mainly responsible for processing, storing and exchanging data of the components they represent, so as to process and update the operating status of the components in a timely manner. The internal control module is a specific component control program. It mainly inputs the corresponding control program to control the operation of different components. Programs, etc., so as to ensure that the components controlled by a single component agent can run safely and stably. At the same time, the component proxy module has anti-interference ability to the outside world, and can make corresponding adjustments to small changes in the outside world, and this process does not require the intervention of the microgrid proxy module, so that the effective operation of the components can be guaranteed.

The micro-grid agent module is mainly aimed at the scheduling and operation inside the micro-grid, and includes four modules: a second grid-connected agent module, a second data processing module, a second data transmission module, and a second data storage module. The second grid-connected agent module is mainly responsible for the grid-connection and disconnection functions of the controlled microgrid to the upper-level grid. The second data processing module is responsible for processing the information provided by the component proxy module, and provides corresponding control strategies for the corresponding component proxy through the second data transmission module according to the result of data processing. The second data storage module mainly stores data for other agents to query. The microgrid agent module is mainly used to optimize the operation of the microgrid or just as a simple regional load dispatch. Its purpose is to make the control of the microgrid more flexible and reduce various losses in the microgrid. The microgrid agent module is mainly responsible for the control of more than one agent, that is, to coordinate and control several agents it manages. For example, when the power distribution network where the microgrid is located is short of power, the microgrid is required to be connected to the grid for power support. At this time, the agent at this level begins to issue commands to adjust the units in the microgrid. adjustment action.

The above power grid agent module mainly provides corresponding strategies for the operation of the medium voltage network and the low voltage network, without specific grid connection control and operation control, including the third data processing module, the third data transmission module, the third data The storage module is mainly responsible for the overall dispatch and strategy analysis of the power network in each region. The third data processing module is responsible for comprehensively processing the data (such as the voltage, current, frequency, active power, and reactive power of each microgrid) transmitted by multiple microgrid agent modules. The multi-objective optimization theory calculates and distributes the adjustment amount and judges whether the energy control strategy is feasible. If it is feasible, it sends instructions to the microgrid agent module through the third data transmission module (if it is not feasible, let each microgrid agent module provide the modified operation directory) . The third data storage module is responsible for storing the data transmitted by each micro-grid agent module and the control strategy data processed by the third data processing module, for query by the micro-grid agent module and the administrator.

Specific application examples:

The system of this embodiment includes a component proxy module, a microgrid proxy module, and a superior grid proxy module. The component agent module includes component agents such as photovoltaic agents, storage battery agents, and wind farm agents. They communicate with microgrid agents in a request/response manner through the data transfer functions in the component modules. The micro-grid agent module includes all micro-grid agents. A small amount of data exchange is performed between each micro-grid agent through communication. The micro-grid agent module and the upper-level grid agent module negotiate control strategies through communication and The control strategy is transmitted to the component agent module through the response mode, and the component agent module controls the corresponding agent by itself.

1. Component agent module

First, according to the characteristics of each power supply, the corresponding agent control function is established through the initialization control module.

1) Wind power generation agent: a. Anti-interference function: In wind power generation, due to the instability of wind speed, there are many harmonics generated by wind power generation. Premium output of quality. b. Wind rotor blade control function related to wind speed: In wind power generation, the link between wind speed and blade control is an important part. This agent needs to be able to adjust the angle of the blade according to the wind speed and set the limit wind speed adjustment. For example: when V _off < V (wind) (that is, the wind speed exceeds the limit speed), the angle of the blades of the wind rotor should be adjusted to ensure the safe and stable operation of the fan. c. Reactive power compensation function: The rapid change of wind power will cause the instability of power transmission. It is necessary to monitor and control the reactive power compensation facilities of wind power generation to meet the requirements of wind power generation stability.

2) Photovoltaic agent: a. Solar maximum power point tracking (MPPT) function: The output characteristics of solar cells are non-linear, and vary with changes in light intensity and temperature. In order to allow it to give full play to its photoelectric conversion capability, the photovoltaic agent must have the maximum power point tracking function. b. Battery panel parameter detection and protection function: monitor the basic parameters of the solar panel, when the above parameters exceed the safe limit range, the agent starts protection measures, such as: low voltage limit mode (LV) to ensure the safety of solar cells run.

3) Gas turbine agent: a. Gas turbine cogeneration function: This function is an important part of the gas turbine agent, and the energy generated by burning natural gas is supplied to the micro gas turbine through energy conversion. Part of the gas turbine provides electricity for the microgrid, and the waste heat generated is provided to the heating system and the cooling system respectively. When the heating and cooling systems require more energy, the system directly burns natural gas to provide energy for the cooling and heating systems. b. Power change limiting function: Since in the case of combined heat and power, the various outputs of the micro gas turbine must meet the needs of heat, and its power change has a certain limit, the power change limiting agent will ensure the combined cooling, heating and power of the gas turbine to be kept within limits. c. Rectification/inversion control function: Due to the speed of the gas turbine, the output current of the gas turbine cannot be directly used in the microgrid. This agent will be responsible for the AC/DC rectifier and DC/AC inverter in the grid connection of the gas turbine The efficient control of the device feeds high-frequency power into the microgrid.

4) Fuel cell agent: a. Hydrogen and oxygen content monitoring and input control function: responsible for monitoring the hydrogen and oxygen content of the battery system, and adjusting the hydrogen and oxygen input according to the hydrogen and oxygen content and battery power generation, so as to achieve the purpose of regulating electric energy. Such as: reduce fuel input, perform low-level operation mode. b. Current density monitoring and adjustment function: When the input gas such as hydrogen and oxygen remains unchanged, there is a good linear relationship between the fuel cell voltage and current density. Through effective monitoring and control of the fuel cell current density , can keep the power generation of the fuel cell within a controllable range.

5) Battery agent: a. Monitoring function: Effective monitoring of the state of the battery can allow the energy of the battery to be effectively controlled before it exceeds the limited range. Including the monitoring of battery voltage, current and energy storage. b. Start-stop/limit function: When the battery reaches the limit value, it stops or starts the input/output of the battery (such as: limit charge and discharge mode) to maintain its reliable operation.

6) Load agent: Classify power loads, monitor load data, remove/connect loads, and maintain mutual communication with microgrid agents.

After these functions are initialized, the corresponding components can be controlled through the corresponding control modules, and the basic information of the proxy components can be transmitted to the microgrid proxy module through the communication module. And through the data storage function, the user can query the information of this component. Finally, the grid-connected module is used to control the grid-connection/disconnection with the microgrid.

2. Micro-grid proxy module: For the micro-grid proxy module, its main function is to comprehensively process the proxy component information after receiving the information provided by each component in the micro-grid and feed back to the corresponding component control strategy to ensure that the micro-grid Safe, stable and efficient operation. In the present invention, the microgrid including photovoltaic power generation, fuel cells and storage batteries is taken as an example to discuss the coordinated control strategy of the microgrid.

1) Control objectives of the microgrid module

For the microgrid agent module, the overall control objective of the microgrid must be formulated first. A common goal is proposed in the present invention, that is, to maximize the power generation efficiency of renewable energy as the control goal:

That is, max∑P _{G, i} (1)

In the formula: _{PG, i} is the power generation of the i-th renewable energy generation component in the microgrid.

2) Constraints of the microgrid module

In order to ensure the safe and stable operation of the microgrid components, the corresponding constraints should be provided after the control objectives of the microgrid module are proposed:

a. Voltage limit

V _min ≤ V(t) _i ≤ V _max (2)

In the formula, V(t) _i is the voltage of each node at time t, and V _max and V _min are 1.05 and 0.95, respectively.

b. Power balance

∑P _{G, i} =D+L (3)

In the formula, D and L are load demand and network loss respectively.

c. Battery energy storage limit

0 ≤ P(t) _s ≤ P _{s, max} (4)

In the formula, P(t) _s is the battery storage capacity at time t, P _s,max = 4.0

d. Battery current limit

ΔI(t) _s ≤ΔI _max (5)

In the formula, ΔI(t) _s is the battery current variation at time t, and ΔI _max =1.25.

e. Photovoltaic power generation restrictions

P(t) _P ≤ P(t) _{P, mppt} (6)

In the formula, P(t) _P is the photovoltaic power generation at time t, P(t) _{P, and mppt} is the power generation during Maximum Power Point Tracking Mode (MPPT). (all parameters are per units)

3) The control strategy of the microgrid agent module when it operates in an isolated island

The coordinated control strategy of the microgrid agent module when it is running in an isolated island is: the microgrid agent module uses the initial data provided by the component agent module, and after the data is processed to obtain the result, then judge the status of each component (photovoltaic, fuel cell, etc.) according to The judgment result determines the control mode of the microgrid components.

a. If the photovoltaic booster and the fuel cell are not running at low level. Then the microgrid agent module communication photovoltaic agent continues to operate in MPPT mode, while the communication fuel cell agent reduces power supply.

b. If the photovoltaic voltage is boosted and the fuel cell is running at a low level. Then the micro-grid agent module communicates with the storage battery agent to charge.

c. Under voltage, the communication battery agent discharges, the fuel cell agent increases power supply, and continues to judge whether the photovoltaic power supply is over, "Yes" - end photovoltaic power generation, and switch to fuel cell power supply, "No" means photovoltaic power generation runs in MPPT mode.

d. Photovoltaic boost and fuel cell low-level operation, the battery agent continues to judge whether the battery exceeds the limit when charging, if so, the microgrid agent notifies the photovoltaic agent to directly change to the voltage limit (VL) mode after receiving the battery agent request, otherwise continue Judging whether the battery is full, if not, continue to keep the photovoltaic agent in MPPT mode, if it is full, change the mode of the photovoltaic agent to VL mode, until the photovoltaic power generation alone cannot maintain voltage stability.

As shown in Figure 5, the flow chart of multi-agent-based microgrid coordination control:

4) The control strategy of the microgrid agent module during grid-connected operation

The microgrid agent module first uses the grid-connected module to connect to the upper-level grid. After grid connection, the coordination scheme of the micro-grid agent module: 1. The communication photovoltaic power generation has always maintained the MPPT mode to maintain the highest power generation efficiency of renewable energy. 2. Due to direct adjustment with the main grid, the microgrid agent module stops the communication battery agent from running. 3. The microgrid agent module will increase the communication and coordination work with the superior grid agent.

3. Upper-level power grid agent module

The upper-level agent module is mainly responsible for the coordination and scheduling work between multiple microgrids and the main grid. For energy dispatching, it can be mainly divided into coordinated dispatching in the stable operation state of the power grid and dispatching in the faulty operating state.

1) Scheduling of the upper-level power grid agent module during steady-state operation

During steady-state operation, after the upper-level power grid agent module synthesizes its lower-level agent information, it analyzes the power grid with the idea of multi-objective optimization, and then coordinates the output of each micro-grid agent. These goals mainly include economic indicators, power quality indicators and so on. When the upper-level power grid agent module assigns a fixed value to the micro-grid agent, the micro-grid agent module can form an effective support for the upper-level power grid through the scheduling of component agents, such as: participate in the frequency, voltage control, and harmonic control of the distribution network wait. It is no longer necessary for the main network to instruct each micro power supply to intervene.

2) Scheduling situation of faulty superior power grid agent module

When a fault occurs after grid connection, due to the distributed nature of the agents, the corresponding agent can quickly locate the location of the fault point. When the fault point is inside the microgrid, the microgrid agent will give corresponding adjustments by integrating the information of each component agent. When it occurs outside the microgrid, the superior grid agent communicates with each microgrid agent to determine the severity of the fault. If it exceeds its self-adjusting ability, the corresponding microgrid agent can choose to disconnect from the main grid and enter the island operation, which can ensure the safe and stable operation of the main grid and the microgrid at the same time.

Based on the above-mentioned system, taking the 9:00-21:00 time period of the day as the blueprint and aiming at maximizing the power generation efficiency of the microgrid, the operation status of each component after the coordinated control of the multi-agent system is analyzed. As shown in Figure 6, it is the parameter map required for simulation, the parabola is the MMPT curve of photovoltaic power generation, and the one with constant amplitude oscillation is the load curve.

Results Data Analysis

1) After simulation, the data diagram in Figure 7 below can be obtained:

The energy change curve of each component in the microgrid is shown in Figure 7, and the corresponding control strategy is shown in Table 1. It can be seen from Figure 7 and Table 1 that each agent in the microgrid has made corresponding mode adjustments in different time periods and under different circumstances. The flexible scheduling of the operation mode allows the microgrid to maintain the maximum efficiency of the microgrid while maintaining safe and stable operation.

Table 1 Schematic diagram of coordinated control strategy

time Operating strategy Photovoltaic agent Battery agent Fuel Cell Agent 9:05-9:55 The photovoltaic output is much smaller than the load consumption. Photovoltaic agents maintain MPPT mode to ensure power generation efficiency. MPPT mode No operation reduce power supply 9:55-10:55 Photovoltaic output rises rapidly and exceeds the load consumption of the microgrid. The microgrid agent communicates with the battery agent to store excess power and orders the fuel cell agent to gradually reduce power generation. MPPT mode charging mode Low output operation mode 10:55-12:45 The photovoltaic output continues to rise, and the excess electric energy has exceeded the limit of short-term charge and discharge of the battery. The battery agent will limit the charge current increase and communicate with the agents. In order to avoid the danger of overvoltage caused by excessive electric energy, the microgrid agent will switch the power generation mode of the communication photovoltaic agent to VL mode. VL mode Extreme charging Low output operation mode 12:45-13:40 The difference between the photovoltaic maximum power output and the electricity load is less than the short-term limit charge and discharge level of the battery, and the photovoltaic power generation agent switches to MPPT mode again. MPPT mode charging mode Low output operation mode

13:40-14:40 When the battery is full, its agents will stop charging and communicate with each agent. Since the photovoltaic output is still greater than the load demand, the photovoltaic agent will be ordered to switch to VL mode again. VL mode stop charging Low output operation mode 14:40-15:10 Photovoltaic output weakens rapidly and load demand cannot be guaranteed. Therefore, the microgrid agent switches the communication photovoltaic agent to MPPT mode, and at the same time notifies the battery agent to provide electric energy. MPPT mode discharge mode Low output operation mode 15:10-15:45 The electrical energy output by photovoltaics is greater than the load consumption again, and the battery agent is stored electrical energy by communication again. MPPT mode charging mode Low output operation mode 15:45-17:15 The sunshine intensity decreases rapidly so that the photovoltaic output is less than the load consumption, the microgrid agent will notify the battery agent to increase the battery discharge current MPPT mode discharge mode Low output operation mode 17:15-17:45 Photovoltaic power generation is rapidly reduced to zero, and batteries alone can no longer meet the electricity demand. At this time, the microgrid agent will communicate with the fuel cell to increase the output of electric energy. MPPT mode Ultimate discharge Increase power supply 17:45-19:50 Photovoltaic power generation is stopped, and the microgrid agent will control the battery agent (to maintain the limit discharge state) and the fuel cell agent to provide sufficient power. stop power generation Ultimate discharge Increase power supply 19:50- During this period, the battery is fully charged, and the entire micro stop power generation stop power supply fully powered The load consumption of the grid is completely provided by the fuel cell.

2) Microgrid node voltage curve

As shown in Figure 8, it can be seen from the figure that in the case of flexible scheduling of the multi-agent system, the voltage of each node of the microgrid is controlled within an acceptable range.

3) Battery charging and discharging current diagram

As shown in Figure 9, it can be seen that due to the existence of battery charge and discharge restrictions and the continuous change of battery current, the battery can effectively supplement and adjust the energy control of the microgrid while maintaining its own safe and stable operation.

Claims (5)

1. micro electric network coordination control system based on multi-agent technology, it is characterized in that comprising: element proxy module, little electrical network proxy module, higher level's electrical network proxy module, described element proxy module, little electrical network proxy module, higher level's electrical network proxy module are divided into three layers and coordinate control, wherein:

The element proxy module is independently controlled each bottom component operation in little electrical network, realizes control, Generation Control, the control of energy-storage travelling wave tube and the control of some loads of direct distributed energy;

Little electrical network proxy module manages the element proxy module at the management and running of little electrical network inside, comprises the receiving element proxy information, provides corresponding control strategies according to little operation of power networks situation and adjustment strategy for little electrical network;

Higher level's electrical network proxy module is responsible for the coordinated scheduling between electricity market and element proxy module, little electrical network proxy module and the higher level's electrical network proxy module, and comprehensive little electrical network proxy information makes very important decision, coordinates to solve task division and shared resource allocation between each agency by communication between little electrical network proxy module and the higher level's electrical network proxy module; Also keep the reasonability of data communication between each proxy module with better each self-decision of assurance;

The element proxy module is controlled each element in little electrical network, and the operation conditions of institute's control element offered little electrical network proxy module, after little electrical network proxy module receives the information of element proxy module, provide control strategy to the element proxy module, change the running status of corresponding control element behind the element proxy module receiving control information voluntarily, the little electrical network proxy module operation conditions of little electrical network separately offers higher level's electrical network proxy module, is undertaken after the preliminary data processing passing to by the information processing system consolidation form by higher level's electrical network proxy module and estimates link; Meanwhile, each little electrical network proxy module is also directly submitted to the running status of little electrical network separately and is estimated link, estimate link and the control strategy of each little electrical network is submitted to corresponding little electrical network proxy module after by model prediction, after little electrical network proxy module changed little operation of power networks state, higher level's electrical network proxy module and little electrical network proxy module were submitted to running status again and are estimated link further to adjust;

Described element proxy module comprises first be incorporated into the power networks proxy module, first data processing module, first data transmission module, first data storage module, the internal control module, wherein: first be incorporated into the power networks proxy module be responsible for control element to little electrical network being incorporated into the power networks and the suspension function, it receives being incorporated into the power networks and suspension information that first data transmission module or little electrical network proxy module provided, and be high priority with the order of being incorporated into the power networks of little electrical network proxy module transmission, the order of being incorporated into the power networks of first data transmission module transmission is that low priority is incorporated into the power networks; First data processing module and first data storage module are responsible for the element of being acted on behalf of is carried out processing, the storage of data, thereby the running status of element is handled timely and upgraded, first data transmission module is responsible for that the element running state information is transferred to little electrical network proxy module and is received the order of little electrical network proxy module; Internal control module is concrete element control program, thereby the input corresponding control programs is controlled different element operations, guarantees the element safe and stable operation that the discrete component agency is controlled, and it receives only the order that first data processing module is transmitted.

2. the micro electric network coordination control system based on multi-agent technology according to claim 1, it is characterized in that, described element proxy module has antijamming capability to external world, can small to external world variation make corresponding adjustment, and this process does not need the interference of little electrical network proxy module.

3. the micro electric network coordination control system based on multi-agent technology according to claim 1, it is characterized in that, described little electrical network proxy module comprises second proxy module that is incorporated into the power networks, second data processing module, second data transmission module, second data storage module, wherein: second be incorporated into the power networks proxy module be responsible for little electrical network of controlling to higher level's electrical network being incorporated into the power networks and the suspension function, it receives being incorporated into the power networks and suspension information that second data transmission module or higher level's electrical network proxy module provided, and the order of being incorporated into the power networks of higher level electrical network proxy module transmission is high priority, and the order of being incorporated into the power networks of second data transmission module transmission is that low priority is incorporated into the power networks; Second data processing module is responsible for the information that the treatment element proxy module is provided when suspension, and provides corresponding control strategies by second data transmission module for the corresponding elements proxy module according to The results of data processing; Second data processing module will increase and the getting in touch of higher level's electrical network proxy module when being incorporated into the power networks, the data that communication module transmitted in receiving element proxy module and the higher level's electrical network proxy module, and provide corresponding control strategies by second data transmission module for the corresponding elements proxy module according to The results of data processing, thereby simultaneously by second data transmission module with the running status of little electrical network once more communication further coordinate control for higher level's electrical network proxy module; Second data storage module stores the result of second data processing module, inquires about for other proxy module.

4. the micro electric network coordination control system based on multi-agent technology according to claim 1, it is characterized in that: described higher level's electrical network proxy module comprises the 3rd data processing module, the 3rd data transmission module, the 3rd data storage module, wherein the 3rd data processing module is responsible for the data that a plurality of little electrical network proxy modules are transmitted are carried out integrated treatment, under the situation that guarantees grid stability, distribute regulated quantity and judge whether energy control strategy is feasible according to the multiple-objection optimization Theoretical Calculation, then by the 3rd data transmission module little electrical network proxy module is sent instruction as feasible, infeasible each little electrical network proxy module that then allows again provides amended operation catalogue; The 3rd data storage module is responsible for storing the data of each little electrical network proxy module transmission and the control strategy data after the processing of the 3rd data processing module, inquires about for little electrical network proxy module and keeper.

5. the micro electric network coordination control system based on multi-agent technology according to claim 1, it is characterized in that, contact between described element proxy module, little electrical network proxy module, the higher level's electrical network proxy module realizes that by communication its communication mode comprises following two kinds:

First kind, the federated systems communication combines with broadcast communication: at first, each proxy module dynamically adds federal body, accept the service that federal body provides, these services comprise that the request of accepting proxy module adds, record adds proxy module ability, task and rank, communication service is provided, proxy module being proposed provides response; Secondly, utilize broadcast mechanism that message is issued each proxy module or a group, the sender specifies unique address, has the proxy module that meets this address only and can read this message;

Second kind, blackboard system: blackboard is that a proxy module writes message, announces the result and obtains the global data base of information, it is divided into several levels according to the agency problem of being studied, the proxy module that works in identical level can be visited corresponding blackboard layer and contiguous level, and the information that is necessary can both be posted on the blackboard for all proxy module retrievals.

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