CN102709949A - Micro-grid coordinated control system - Google Patents

Abstract

The invention provides a micro-grid coordinated control system, which comprises an energy management system, a main controller and a terminal unit; the energy management system is in communication connection with the main controller by adopting transmission control protocol (TCP)/Internet protocol (IP); and the main controller is in communication connection with the terminal unit through an EtherCAT bus. According to the micro-grid coordinated control system, according to the weaknesses of the existing micro-grid control system, a solution of the micro-grid coordinated control system based on the EtherCAT bus is provided, so that the digitalization and the real-time performance of the micro-grid control system can be improved.

Description

A Coordinated Control System for Microgrid

technical field

The invention belongs to the field of power systems, and in particular relates to a micro-grid coordination control system.

Background technique

Micro-grid technology, due to the actual national conditions and development of different countries, the concept and development goals of micro-grid are not the same. Among them, the concept of micro-grid was first proposed, and one of the more authoritative definitions of micro-grid is the definition of micro-grid proposed by the American Electrical Reliability Technology Solutions Association: Micro-grid is a micro power supply (less than or equal to 500kW) based on power electronics technology. It is a system composed of load and load, which can provide electric energy and heat at the same time to realize combined heat and power supply; the power supply inside the microgrid mainly has power electronic devices responsible for energy conversion and provides necessary control; compared with the external large grid, the microgrid is a single The controlled unit can meet the user's requirements for power quality and power supply safety and reliability at the same time.

The flexible operation mode and high-quality power supply service of the microgrid are inseparable from a perfect and stable control system. In the actual coordinated control of the microgrid, it is necessary to record in real time the current, voltage, power and other information collected by the slave stations such as the distributed power supply measurement and control terminal and the grid-connected protection measurement and control terminal, and to transmit this information to the master station in real time. , the master station should also analyze and process the collected information in time, and transmit control parameters to the slave station. Constrained by the field environment of the microgrid, the distance between the master station and the slave station is often relatively long, and the traditional fieldbus technology cannot guarantee the real-time performance of signal transmission. Therefore, the existing micro-grid control system adopts two methods to solve the above existing problems. One is the simplest method, which is to connect the analog values such as current and voltage and the switch values such as the position of the circuit breaker directly to the main station through cables. This method needs to lay a large number of cables, and the wiring is complicated; another method is to use a coordinated control method in which the master station control decision is separated from the slave station control decision, but this method has poor systemicity, and there is a gap between the master station and the slave station. The time difference that exists may cause the disadvantage that the master-slave decision-making conflicts with each other.

Contents of the invention

In order to overcome the above-mentioned defects, the present invention provides a micro-grid coordinated control system. According to the deficiencies of the existing micro-grid control system, a scheme of a micro-grid coordinated control system based on the EtherCAT bus is proposed to improve the digitalization and control of the micro-grid control system. real-time.

To achieve the above object, the present invention provides a microgrid coordinated control system, which includes: an energy management system, a main controller and a terminal unit; the energy management system and the main controller are connected by TCP/IP ; The improvement is that the main controller and the terminal unit are connected by EtherCAT bus.

In the preferred technical solution provided by the present invention, the terminal unit includes a grid-connected point terminal, a main power supply terminal, a load terminal, a distributed power supply terminal and an environmental monitoring terminal connected in sequence; the terminals are connected by EtherCAT bus for communication.

In the second preferred technical solution provided by the present invention, each terminal includes: a communication control unit, an application processing unit, a module number conversion unit, and an I/O interface; the application processing unit communicates with the communication control unit, the The module number conversion unit and the I/O interface are connected by communication.

In the third preferred technical solution provided by the present invention, the communication control unit includes: a DPRAM and a communication interface module; the DPRAM communicates with the application processing unit; the communication interface module communicates with the main control unit through the EtherCAT bus device or adjacent terminals for communication connection; the communication control unit uses a chip model ET1100.

In the fourth preferred technical solution provided by the present invention, the application processing unit realizes the collection of current and voltage analog quantities through the module number conversion unit, and completes the collection of switching quantities and the output of control signals through the I/O interface; The application processing unit adopts a chip of model TMS320C28335; the module digital conversion unit adopts an analog-to-digital converter of model ADS8556.

In the fifth preferred technical solution provided by the present invention, the main controller includes: a control module, and an interface module and a human-machine interface module respectively communicating with it.

In the sixth preferred technical solution provided by the present invention, the control module includes an Ethernet port and a DVI interface; the control module communicates with the energy management system through the Ethernet port; the interface module includes: two One RJ45 interface, select one of the two RJ45 interfaces to communicate with the terminal unit through the EtherCAT bus; the control module communicates with the man-machine interface module through the DVI interface; the control module adopts a model of CX1020 The embedded controller; the man-machine interface module is a 17-inch touch screen.

In the seventh preferred technical solution provided by the present invention, the control module is provided with a TwinCAT component.

In the eighth preferred technical solution provided by the present invention, the TwinCAT component includes a system manager and configuration information arranged side by side; the system manager reads the nodes of each terminal, DC clock synchronization, topology, configuration slave station parameters and The function of viewing the IO volume of the slave station in real time; the configuration information exists in the form of an XML file, with a built-in XML interpreter, including the master controller configuration file and the terminal unit configuration file.

In the ninth preferred technical solution provided by the present invention, the main controller configuration file includes the set network segment parameters, the commands executed at startup, the basic configuration of the terminal unit and the configuration of the operating environment; the terminal unit configuration file includes the set terminal Unit initialization configuration and terminal unit information, the terminal unit configuration file is interpreted and transmitted to each terminal of the terminal unit.

Compared with the prior art, the micro-grid coordinated control system provided by the present invention adopts the EtherCAT bus as the communication architecture of the micro-grid coordinated control system, which satisfies the real-time performance of the micro-grid coordinated control system, and does not need to disperse The analog quantities such as current and voltage of the equipment and the switching quantities such as the position of the circuit breaker are connected to the central controller through cables, which reduces the laying of cables, simplifies the wiring mode, and realizes the digitization of the entire microgrid system; moreover, it meets the requirements of centralized control decision-making The real-time requirement for the control of the entire microgrid system avoids the conflict between the control decision of the master station and the control decision of the slave station due to the time difference between the master station and the slave station.

Description of drawings

FIG. 1 is a structural diagram of an embodiment of a microgrid coordinated control system based on an EtherCAT bus.

FIG. 2 is a structural diagram of an embodiment of a micro-grid local terminal as an EtherCAT slave station.

Fig. 3 is a communication schematic diagram of the microgrid coordinated control system of the EtherCAT bus.

Fig. 4 is a schematic diagram of an embodiment of the main controller hardware architecture.

Fig. 5 is a schematic diagram of an embodiment of a hardware architecture of a single terminal.

Detailed ways

The technical scheme of the present invention is as follows: the microgrid coordination control system based on the EtherCAT bus is composed of a main controller and various terminals. /IP for communication connection. As shown in Figure 1.

As the master station of EtherCAT, the main controller usually uses a standard Ethernet network card NIC (Network Interface Card) as the hardware interface of the master station, and uses a PC or an embedded controller as the hardware basis. Its functions are realized by software. The software part includes two parts, the basic program and the application program. The basic program mainly completes basic functions such as initialization, topology identification, parameter setting, data display and storage; the application program mainly makes decisions on the operation status of the microgrid, and sends the adjusted control commands after the decision to each local terminal through the EtherCAT bus , mainly including decision-making procedures for grid-connected microgrid operation, island operation decision-making procedures, grid-connected to isolated island decision-making procedures, isolated island-to-grid-connected decision-making procedures, etc.

The local terminal is the slave station of EtherCAT, and the hardware is mainly composed of the slave station control ESC chip, the application layer CPU chip, etc., as shown in Figure 2. The ESC chip mainly implements data exchange with the EtherCAT bus, and the application layer CPU chip mainly implements functions such as AD sampling, data calculation and processing, input signal processing, and export control. According to the different objects in the connected microgrid system, it can be divided into grid-connected point terminals, main power supply terminals, load terminals, distributed power supply terminals, and environmental monitoring terminals.

The grid-connected point terminal refers to the terminal corresponding to the grid-connected point circuit breaker, which can collect analog quantities such as voltage, current, and frequency on both sides of the grid-connected circuit breaker (ie, the main grid side and the micro-grid side); It has a control outlet for opening and closing functions of the circuit breaker at the grid-connected point; it has a protection function, which can judge and remove faults on the main grid side or micro grid side; it has the functions of checking synchronization and checking no-voltage closing.

The main power supply terminal is mainly aimed at the energy storage device or fuel cell that operates in FV mode and assumes the main power supply function when the microgrid is running in an isolated island. It has the function of collecting analog quantities such as voltage, current, and power of the main power supply; Binary input such as the operating state and operating mode; it has control outlets for controlling the start and stop of the main power supply, switching from PQ mode to FV mode, and from FV mode to PQ mode.

There are multiple load terminals in a microgrid, corresponding to each load switch in the microgrid, collecting analog quantities such as current, voltage, and power of the load; collecting switch quantities such as the position of the load switch; Control exports.

There are also multiple distributed power terminals in a microgrid, which correspond to power sources other than the main power supply. According to the types of distributed power sources, they can be divided into: photovoltaic power generation terminals, wind power generation terminals, fuel cell terminals, etc. The distributed power supply terminal has the function of collecting analog quantities such as voltage, current, and power of the distributed power supply; it can collect binary inputs such as the operating status of the distributed power supply; it has a control outlet for controlling the start and stop of the distributed power supply.

The environmental monitoring terminal corresponds to the environmental monitoring system, and is mainly used to receive environmental parameters such as temperature, humidity, solar radiation, and wind force measured by the environmental monitoring system.

The communication principle of the microgrid coordinated control system based on the EtherCAT bus is shown in Figure 3. The main controller, as the EtherCAT master station, is responsible for the initiation and control of the message. The maximum effective data length of the message is 1498 bytes, and the data traversal All local end equipment. As an EtherCAT slave station, the local terminal device does not store the data packets and then process them, but when the downlink message passes, it extracts data from the data frame or inserts the data into the data frame according to the specified position in the message header. At the same time, the message is transmitted to the next local terminal. When the message arrives at the last terminal in the logical position of the system, the terminal returns the processed message as an uplink message to the main controller. This communication process is all completed by the ESC chip, and the processing delay is only about 10ns. Compared with the traditional Ethernet, the real-time performance has been greatly improved.

Specific embodiments of the present invention are described in further detail below. This embodiment is implemented under the premise of the technical solution of the present invention, and detailed implementation is provided, but the protection scope of the present invention is not limited to the following examples.

This embodiment selects the embedded controller CX1020 of BECKHOFF Company as the hardware platform of the main controller, and this controller adopts Intel Celeron processor, configures 256MB internal memory, 2GB CF card, WinCE operating system. CX1020 comes with a DVI interface, through which a 17 o'clock touch screen is connected as the man-machine interface. CX1020 comes with two Ethernet ports, choose one of the Ethernet ports to connect with the upper energy management system through TCP/IP. An EK1122 module from BECKHOFF is also selected. This module is an EtherCAT topology interface terminal module with two RJ45 interfaces. One of the interfaces is selected to connect to the IN network port of the first EtherCAT substation through a network cable. The hardware platform of the master station is shown in Figure 4.

The main controller software chooses the TwinCAT software of BECKHOFF Company as the main station software of EtherCAT. TwinCAT integrates the EtherCAT protocol stack and real-time kernel inside. The main platform of TwlnCAT is the system manager. Through the system manager, you can read EtherCAT slave nodes, DC clock synchronization, topology structure, configure slave station parameters, and view the IO volume of slave stations in real time. The configuration information of TwinCAT exists in the form of XML files, with a built-in XML interpreter, which is divided into master station configuration files and slave station configuration files. In the master station configuration file, you can set the network segment parameters, the commands executed at startup, the basic configuration of the slave station, the configuration of the operating environment, etc.; the slave station configuration file can set the initialization configuration and slave station information of the slave station. Download to the slave station.

The local terminal is used as the EtherCAT slave station, and the ET1100 chip of BECKHOFF Company is selected as the EtherCAT slave station control ECS chip, which realizes the physical layer and data link layer of the EtherCAT slave station protocol. The chip has 4 physical communication ports, supports 100Mbit/s full-duplex communication, and has 8KB of DPRAM inside to exchange data with the application layer CPU. The application layer CPU chip of the slave station uses TI's DSP chip TMS320C28335, which is a 32-bit floating-point CPU with 68KB of RAM and 512KB of Flash, 12-bit AD, and strong processing capabilities. On the one hand, TMS320C28335 is connected with the DPRAM of ET1100 through the bus line, and both parties exchange and share data through DPRAM. On the other hand, TMS320C28335 realizes the acquisition of analog quantities such as current and voltage of the local terminal through the AD sampling loop, and completes the acquisition of switching quantities and the export of control signals through the IO interface loop. The hardware architecture of the local terminal is shown in Figure 5.

It should be declared that the contents and specific implementation methods of the present invention are intended to prove the practical application of the technical solutions provided by the present invention, and should not be construed as limiting the protection scope of the present invention. Those skilled in the art may make various modifications, equivalent replacements, or improvements under the inspiration of the spirit and principles of the present invention. But these changes or modifications are all within the protection scope of the pending application.

Claims (10)

1. micro electric network coordination control system, it comprises: EMS, master controller and terminal unit; Adopt TCP/IP to communicate connection between said EMS and the said master controller; It is characterized in that said master controller communicates with terminal unit employing EtherCAT bus and is connected.

2. system according to claim 1 is characterized in that, terminal unit comprises the point terminal that is incorporated into the power networks, main power source terminal, loaded termination, distribution power terminal and the environmental monitoring terminal that connects successively; Adopt the EtherCAT bus to communicate connection between said each terminal.

3. system according to claim 2 is characterized in that, said each terminal comprises respectively: communication control unit, application processing unit, number of modules converting unit and I/O interface; Said application processing unit communicates with said I/O interface with said communication control unit, said number of modules converting unit respectively and is connected.

4. system according to claim 3 is characterized in that, said communication control unit comprises: DPRAM and communication interface modules; Said DPRAM communicates with said application processing unit and is connected; Said communication interface modules communicates with said master controller or neighboring terminals through the EtherCAT bus and is connected; It is the chip of ET1100 that said communication control unit adopts model.

5. system according to claim 3 is characterized in that, said application processing unit is accomplished the collection of switching value and the output of control signal through the collection of said number of modules converting unit realization electric current, voltage analog through said I/O interface; It is the chip of TMS320C28335 that said application processing unit adopts model; It is the analog to digital converter of ADS8556 that said number of modules converting unit adopts model.

6. system according to claim 1 is characterized in that, said master controller comprises: control module and interface module that communicates with respectively and human-computer interface module.

7. system according to claim 6 is characterized in that, said control module comprises ethernet port and DVI interface; Said control module communicates through ethernet port and said EMS; Said interface module comprises: two RJ45 interfaces that are set up in parallel, select two RJ45 interfaces in one communicate with said terminal unit through the EtherCAT bus and to be connected; Said control module communicates through DVI interface and said human-computer interface module; It is the embedded controller of CX1020 that said control module adopts model; Said human-computer interface module is 17 cun a touch-screen.

8. according to claim 6 or 7 described systems, it is characterized in that said control module is provided with the TwinCAT assembly.

9. system according to claim 8 is characterized in that, said TwinCAT assembly comprises system administration manager and the configuration information that is set up in parallel; Said system administration manager reads the function of node, DC clock synchronization, topological structure, configuration slave station parameter and the real time inspection slave station IO amount at each terminal; Configuration information exists with the form of XML file, and built-in XML interpreter comprises master controller configuration file and terminal unit configuration file.

10. system according to claim 9 is characterized in that, the master controller configuration file comprises the network segment parameter of setting, order, the basic configuration of terminal unit and the configuration of carrying out when starting of running environment; The terminal unit configuration file comprises the initial configuration and the terminal unit information of the terminal unit of setting, and said terminal unit configuration file is through being transferred to each terminal of said terminal unit after explaining.

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