Micro-grid layered and centralized control method and system

Abstract

The invention relates to the field of micro-grids, and discloses a micro-grid hierarchical and centralized control method and system, and a micro-grid hierarchical control structure comprises a zeroth layer and equipment layers of subsystems of a micro-grid. The first layer is a control layer of each subsystem device of the micro-grid and is used for completing device-level control of each subsystem of the micro-grid; the second layer is an energy management layer which regulates and controls power and voltage through the control signal sent by the first layer so as to realize power balance and microgrid voltage stabilization; the third layer is an operation and energy debugging layer, energy production scheduling instructions of subsystems of the micro-grid are regulated and controlled to serve as energy instructions of the second layer, the operation and energy debugging layer comprises a centralized control system, the centralized control system comprises a plurality of centralized controllers, and the centralized controllers have an inter-station communication function and are used for centralized control of the whole system; according to the invention, the power control of the whole system of each subsystem in the micro-grid and the real-time control function of a multi-target system are realized, and the control stability of the micro-grid system is improved.

Description

Technical Field

[0001] The present invention relates to the field of microgrids, and in particular to a microgrid hierarchical and centralized control method and system. Background Art

[0002] A microgrid is composed of loads and micro power sources, forming a single controllable unit. The controllable unit is dispatched according to the energy load of each subsystem of the microgrid. The controllable unit can meet the requirements of users within the microgrid for power quality, power supply reliability and safety.

[0003] The controllers of each subsystem of the existing technical architecture constitute the first control layer. The controllers of each subsystem are independent of each other, making it difficult to achieve flexible control of multi-system shared power units, real-time control of multi-objective control systems, and coordinated control of each subsystem in the microgrid mainly through the energy dispatch management layer. The real-time control is not high and the time delay is large. With the development of microgrid technology, each subsystem in the microgrid adopts an independent control principle. It is difficult to achieve flexible control of shared power units with existing technology; the control targets of the power flexible distribution layer, device control layer and energy management layer of each subsystem of the microgrid are inconsistent, and it is difficult to achieve multi-objective control of each subsystem of the microgrid with existing technology; the real-time operating parameters and demand information of the coordinated control of each subsystem in the existing technology need to be completed through the device control layer-energy management layer-energy dispatch layer-energy management layer-device control layer to complete information exchange, and the real-time performance of the system is poor. For coordinated control with high real-time requirements, it is difficult to meet the real-time requirements of coordinated control.

[0004] With the development of microgrid technology, it is impossible to achieve flexible control of the power units of the three subsystems in an integrated photovoltaic storage and charging device composed of a new energy vehicle charging station, an energy storage system, and a photovoltaic system. In more microgrid system application scenarios, such as commercial microgrid systems such as hotels and office buildings composed of photovoltaic systems, energy storage systems, and full DC air conditioning systems, and industrial microgrids composed of photovoltaic systems, wind power generation systems, energy storage systems, full DC compression systems, cooling systems, and thermal storage systems, shared power units will be involved. The existing underlying control system composed of multiple subsystem controllers cannot achieve flexible control of multi-system shared power units, real-time control of multi-objective control systems, and real-time centralized control of distributed power sources. Due to the relative independence of each subsystem in the existing technology, each subsystem has its own safety protection system. The coordinated control of the entire microgrid is mainly completed by the third-layer operation management and energy dispatching system, which makes it difficult to achieve the real-time requirements of the safety interlocking protection of the entire microgrid system. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a microgrid hierarchical and centralized control system. The microgrid hierarchical control structure includes the zeroth layer, the equipment layer of each subsystem of the microgrid; the first layer, the control layer of the equipment of each subsystem of the microgrid, which completes the equipment-level control of each subsystem of the microgrid; the second layer, the energy management layer, which regulates power and voltage through the control signal sent by the first layer to achieve power balance and microgrid voltage stability; the third layer, the operation and energy debugging layer, regulates the energy production scheduling instructions of each subsystem of the microgrid as the energy instructions of the second layer, including a centralized control layer, the centralized control layer includes multiple centralized controllers, and the multiple centralized controllers have inter-station communication functions for centralized control of the entire system; the centralized control layer and the control systems of each subsystem of the microgrid realize data interaction through a communication gateway, and the communication gateway converts the communication protocol of each subsystem of the microgrid into the communication protocol of the centralized control system.

[0006] Each subsystem of the microgrid is composed of equipment at the equipment layer, a power flexible distribution system at the power flexible distribution layer, an equipment control system at the equipment control layer, an energy management system at the energy management layer, and an operation and energy dispatching system at the operation and energy dispatching layer;

[0007] The power flexible distribution layer is composed of shared power receiving units of two or more microgrid subsystems.

[0008] Preferably, the centralized controller and the energy management systems of the microgrid subsystems also implement data interaction through a communication gateway, and the communication gateway converts the communication protocols of the microgrid subsystems into the communication protocol of the centralized control system.

[0009] Preferably, the centralized controller and the device control layer of each subsystem of the microgrid realize data exchange through a communication gateway, and the communication gateway converts the communication protocol of the device control layer of each subsystem of the power grid into the communication protocol of the centralized controller system.

[0010] Preferably, it also includes a flexible power unit, and the flexible power unit and the centralized controller perform data exchange via a communication gateway.

[0011] Preferably, in the equipment layer of each subsystem of the microgrid, the control logic, control algorithm, and safety protection of the control system are separated from the power setting value and the optimal target control value of the control system of each subsystem of the microgrid. The power setting value and the optimal target control value of the control system of each subsystem of the microgrid are set by the centralized control system; the real-time operating value of each subsystem of the microgrid is transmitted to the centralized control system via communication, and the centralized control system calculates the optimal power control setting value and multi-target control value of each subsystem of the microgrid based on the real-time operating value of each subsystem of the microgrid and the energy dispatching information of the energy management layer, and writes them into the control system of each subsystem of the microgrid via communication.

[0012] Preferably, the centralized control system performs safety interlocking of the entire system according to a set safety interlocking procedure based on the real-time data collected from each subsystem of the microgrid, when the real-time data collected from each subsystem of the microgrid exceeds a safety set value.

[0013] Preferably, when the communication protocol of the control system of each subsystem of the microgrid is inconsistent with the protocol of the centralized control system, the communication protocol is converted through a communication gateway to match the communication protocol of the centralized control system.

[0014] Preferably, when there is a shared flexible power unit between the subsystem devices of the microgrid, the centralized control system allocates the power calculation value according to the power demand signal of each subsystem of the microgrid through the control program of the centralized controller of the centralized control layer and sends it to the shared flexible power unit, thereby realizing coordinated control of the centralized control system, the control systems of the subsystems of the microgrid and the shared flexible power unit.

[0015] A microgrid hierarchical and centralized control method, characterized by being applied to a microgrid hierarchical and centralized control system as described in any one of claims 1-8.

[0016] The beneficial effects of the present invention are as follows: the present invention realizes the power control of the whole system of each subsystem in the microgrid and the real-time control function of the multi-objective system, and the real-time performance of the coordinated control at each level is improved from seconds to milliseconds, thereby improving the control stability of the microgrid system.

[0017] The present invention realizes the cooperative control function of the shared power unit between subsystems, and saves the investment cost of the power unit.

[0018] The present invention realizes the whole system level safety protection function of the microgrid, improves the system safety protection function of the microgrid, and improves the safety of the operation of the microgrid.

[0019] The present invention realizes the centralized control function of the microgrid and realizes the coordinated control function of the entire microgrid system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the principle of a microgrid hierarchical and centralized control system;

[0021] Figure 2 A schematic diagram of an embodiment of a microgrid hierarchical and centralized control system;

[0022] Figure 3 Schematic diagram of the existing microgrid technology architecture. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0024] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0025] like Figure 1 As shown, a microgrid hierarchical and centralized control system, the microgrid hierarchical control structure includes the zeroth layer, the equipment layer of each subsystem of the microgrid; the first layer, the control layer of the equipment of each subsystem of the microgrid, which completes the equipment-level control of each subsystem of the microgrid; the second layer, the energy management layer, which regulates power and voltage through the control signal sent by the first layer to achieve power balance and voltage stability of the microgrid; the third layer, the operation and energy debugging layer, regulates the energy production scheduling instructions of each subsystem of the microgrid as the energy instructions of the second layer, including a centralized control layer, the centralized control layer includes multiple centralized controllers, and the multiple centralized controllers have inter-station communication functions for centralized control of the entire system; the centralized control layer and the control systems of each subsystem of the microgrid realize data interaction through a communication gateway, and the communication gateway converts the communication protocol of each subsystem of the microgrid into the communication protocol of the centralized control system.

[0026] Each subsystem of the microgrid is composed of equipment at the equipment layer, a power flexible distribution system at the power flexible distribution layer, an equipment control system at the equipment control layer, an energy management system at the energy management layer, and an operation and energy dispatching system at the operation and energy dispatching layer;

[0027] The power flexible distribution layer is composed of shared power receiving units of two or more microgrid subsystems.

[0028] The centralized controller and the energy management systems of each subsystem of the microgrid also realize data interaction through the communication gateway, and the communication gateway converts the communication protocol of each subsystem of the microgrid into the communication protocol of the centralized control system.

[0029] The centralized controller and the device control layer of each subsystem of the microgrid realize data exchange through the communication gateway, and the communication gateway converts the communication protocol of the device control layer of each subsystem of the power grid into the communication protocol of the centralized controller system.

[0030] It also includes a flexible power unit, and the flexible power unit and the centralized controller perform data exchange via a communication gateway.

[0031] In the equipment layer of each subsystem of the microgrid, the control logic, control algorithm, and safety protection of the control system are separated from the power setting value and the optimal target control value of the control system of each subsystem of the microgrid. The power setting value and the optimal target control value of the control system of each subsystem of the microgrid are set by the centralized control system; the real-time operating value of each subsystem of the microgrid is transmitted to the centralized control system via communication. The centralized control system calculates the optimal power control setting value and multi-target control value of each subsystem of the microgrid based on the real-time operating value of each subsystem of the microgrid and the energy dispatching information of the energy management layer, and writes them into the control system of each subsystem of the microgrid via communication.

[0032] The centralized control system collects real-time data from each subsystem of the microgrid. When the real-time data from each subsystem of the microgrid exceeds the safety set value, the entire system is interlocked according to the set safety interlock procedure.

[0033] When the communication protocol of the control system of each subsystem of the microgrid is inconsistent with the protocol of the centralized control system, the communication protocol conversion is realized through the communication gateway to match the communication protocol of the centralized control system.

[0034] When there is a shared flexible power unit among the subsystem devices of the microgrid, the centralized control system allocates the power calculation value according to the power demand signal of each subsystem of the microgrid through the control program of the centralized controller of the centralized control layer and sends it to the shared flexible power unit, thereby realizing the coordinated control of the centralized control system, the control systems of each subsystem of the microgrid and the shared flexible power unit.

[0035] A microgrid hierarchical and centralized control method, characterized by being applied to the microgrid hierarchical and centralized control system.

[0036] Specifically, the underlying control system of the microgrid is completed by various subsystems. Each subsystem has different control objects, control principles, control response times, and control quality. It is difficult to achieve centralized control of each subsystem. Each subsystem belongs to a different industry and is integrated by different equipment manufacturers. The control system and equipment are highly integrated. The operation quality and safety of the device are closely integrated with the control system of the subsystem. It is difficult to separate the device and the control system to form a centralized controller for multiple subsystems.

[0037] The microgrid centralized control method and system of the present invention are as follows Figure 3 As shown,

[0038] A centralized control system 300 is added on the basis of the traditional hierarchical control system. The centralized control system 300 includes at least one or more centralized controllers. There can be inter-station communication between the multiple centralized controllers to realize the centralized control function of the whole system.

[0039] The centralized controller and the control systems 400 of each subsystem use a communication method to achieve data interaction. The communication method can select a communication gateway for communication protocol conversion to convert the communication protocol of the control system 400 of each subsystem into the communication protocol of the centralized control system 300;

[0040] The centralized controller and the energy management system 200 of each subsystem use a communication method to realize data interaction. The communication method can select a communication gateway for communication protocol conversion to convert the communication protocol of the energy management system 200 of each subsystem into the communication protocol of the centralized control system 300;

[0041] The system may optionally include a flexible power unit 500, and the flexible power unit 500 and the centralized controller use a communication method to realize data interaction;

[0042] The control logic, control algorithm, safety protection and other functions of the control system 400 of each subsystem of the device layer 600 of each subsystem of the present invention are separated from the power setting value, the optimal target control value of the control system 400 of each subsystem and the control system 400 of each subsystem, and the power control setting value of the control system 400 of each subsystem and the optimal target control value of the control system 400 of each subsystem are given by the centralized control system 300. The real-time operation value of the control system 400 of each subsystem is transmitted to the centralized control system 300 by communication. The centralized control system 300 calculates the optimal power control setting value of the control system 400 of each subsystem and the multi-target control value of the control system 400 of each subsystem according to the collected real-time operation value of the control system 400 of each subsystem, and writes them into the control system 400 of each subsystem by communication. The power control and multi-target system real-time control of the control system 400 of each subsystem are separated, and the power control and multi-target system real-time control are realized by the centralized control system 300.

[0043] Optionally, any or all functions of the control system 400 of each subsystem, power control, and multi-objective system real-time control may be implemented.

[0044] Optionally, the centralized control system 300 collects real-time data from the control systems 400 of each subsystem. When the collected parameters exceed the safety set values, the centralized control system 300 implements the safety interlock function of the entire system according to the set safety interlock program.

[0045] When the communication protocol of the control system 400 of each subsystem of the present invention is inconsistent with the protocol of the centralized control system 300, a gateway device can be used to convert the communication protocol into the communication protocol of the centralized control system.

[0046] Optionally, when the communication protocol of the control system 400 of each subsystem is inconsistent with that of the centralized control system 300, communication protocol conversion software can be used in the centralized control system 300 to convert the communication protocol of the control system 400 of each subsystem into the communication protocol of the centralized control system.

[0047] Optionally, the data interaction between the control system 400 of each subsystem and the centralized control system 300 may be performed in a hard-wired manner.

[0048] The coordinated control and real-time performance of the control system 400 of each subsystem and the centralized control system 300 of the present invention solve the real-time problem by directly communicating between the control system 400 of each subsystem and the centralized control system 300. The centralized controller realizes the coordinated control problem according to the coordinated control algorithm of each subsystem 300.

[0049] When there is a shared flexible power unit 500 between the equipment layer 600 devices of each subsystem of the present invention, the centralized control system 300 flexibly allocates the power calculation value according to the control program based on the power demand signal of the control system 400 of each subsystem and sends it to the shared flexible power unit 500, thereby realizing the collaborative control function of the centralized control system 300 and the control system 400 of each subsystem and the shared flexible power unit 500.

[0050] According to the real-time requirements of the safety interlock protection of the whole microgrid system, the communication speed of the safety protection collection data and control instructions of the control system 400 of each subsystem is set according to the safety protection requirements to achieve the real-time requirements of the safety interlock protection of the whole system.

[0051] Optionally, the security protection collection data and control instructions of the control system 400 of each subsystem and the signal transmission of the centralized control system 300 are hard-wired.

[0052] To make the purpose, technical solutions and advantages of the present invention more clear, the following will be combined with the attached Figure 2 The specific embodiments of the implementation method of the present invention are described in further detail.

[0053] Reference Figure 2 The centralized control system 300 can select a programmable controller (PLC), a distributed control system (DCS), an industrial computer, a single-chip controller, a PC or a server running a control program, etc.

[0054] One or more controllers of the selectable centralized control system 300 may be selected.

[0055] Reference Figure 2 The communication protocol between the centralized control system 300 and the control systems 400 of each subsystem and the energy management system 200 of each subsystem can be selected from CAN, CANFD, EtherCat, modbus, Ethernet, Profinet, IEC104 and other communication protocols. It can also be other communication protocols not listed.

[0056] Optionally, the data interaction between the centralized control system 300 and the control systems 400 of each subsystem and the energy management system 200 of each subsystem can be selected as a hard-wired method. The centralized control system 300 and the control systems 400 of each subsystem are configured with digital quantity input cards (DI), digital quantity output cards (DO), model quantity input cards (AI), and model quantity output cards (AO) to realize the signal transmission of digital quantities and model quantities between systems.

[0057] Reference Figure 2 The gateway can be a CAN to modbus gateway, a CAN to EtherCat gateway, an IEC104 to modbus gateway, etc. The specific situation is to select a suitable gateway according to the communication protocol of the control system 400 of each subsystem and the communication protocol of the centralized control system 300.

[0058] Optionally, the centralized control system 300 can run a communication protocol conversion gateway software to implement communication protocol conversion in the controller. The gateway software can be KepWar, Ifix, etc., or it can be developed using high-level languages ​​such as C++, C#, JAVA, etc. to implement the communication protocol conversion function in the centralized control system 300.

[0059] Reference Figure 2 ,The communication speed of the communication protocol between the centralized control system 300 and the control systems 400 of each subsystem can be selected as 50ms, 100ms, 200ms, 500ms, etc. to meet the real-time requirements of the communication.

[0060] Reference Figure 2, the power control of the centralized control system 300 and the control systems 400 of each subsystem, and the real-time control of the multi-objective system. For example, the controller of the charging pile of the charging station equipment in the 400 subsystem reads the charging power, charging voltage, charging current, charging capacity, SOC and other information of the charged new energy vehicle, and uploads it to the centralized control system 300 by communication. The centralized control 300 performs flexible power allocation calculation based on the read data, and outputs instructions to the shared flexible power unit 500 by communication. The shared flexible power unit 500 charges the corresponding new energy vehicle of the 400 charging station according to the received instructions. The charging power, charging voltage, charging current, charging capacity, SOC and other parameters of the charging are used as control instructions of the shared flexible power unit 500 to realize the power control of the charging control of the new energy vehicle.

[0061] The shared flexible power unit 500 serves as a shared unit for the energy storage subsystem and the charging station subsystem. The two subsystems have different control parameters (charging power, charging voltage, charging current, charging capacity, SOC, etc.). To achieve real-time control of the multi-objective system of the two subsystems, the centralized control system collects demand data from each subsystem and communicates the multi-objective parameters to the shared flexible power unit 500 in real time via communication, thereby achieving real-time control of the multi-objective system.

[0062] The control systems of each subsystem, the centralized control system and the shared flexible power unit 500 together form a flexible power real-time control system, realizing the same control function of multiple subsystems of the shared flexible power unit 500.

[0063] Reference Figure 2 , the equipment layer 600 of each subsystem, for example, if a combustion accident occurs in the energy storage cell cabinet of the energy storage subsystem, the energy storage subsystem of the subsystem will send the detected combustion detection signal to the centralized control system by communication. The centralized system will automatically cut off the power supply of the equipment layer 600 of each subsystem according to the set safety protection program, to prevent the expansion of the accident, and realize the safety protection function of the whole microgrid system.

[0064] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A hierarchical and centralized control system for a microgrid, wherein the hierarchical control structure of the microgrid includes the zeroth layer, the equipment layer of each subsystem of the microgrid; the first layer, the control layer of each subsystem of the microgrid, which completes the equipment-level control of each subsystem of the microgrid; the second layer, the energy management layer, which regulates power and voltage through the control signal sent by the first layer to achieve power balance and voltage stability of the microgrid; the third layer, the operation and energy debugging layer, which regulates the energy production scheduling instructions of each subsystem of the microgrid as the energy instructions of the second layer, characterized in that It includes a centralized control layer, which includes multiple centralized controllers. The multiple centralized controllers have inter-station communication functions for centralized control of the entire system; the centralized control layer and the control systems of each subsystem of the microgrid realize data interaction through a communication gateway, and the communication gateway converts the communication protocols of each subsystem of the microgrid into the communication protocol of the centralized control system. Each subsystem of the microgrid is composed of equipment at the equipment layer, a power flexible distribution system at the power flexible distribution layer, an equipment control system at the equipment control layer, an energy management system at the energy management layer, and an operation and energy dispatching system at the operation and energy dispatching layer; The power flexible distribution layer is composed of shared power units of two or more microgrid subsystems.

2. A microgrid hierarchical and centralized control system according to claim 1, characterized in that: The centralized controller and the energy management systems of each subsystem of the microgrid also realize data interaction through the communication gateway, and the communication gateway converts the communication protocol of each subsystem of the microgrid into the communication protocol of the centralized control system.

3. A microgrid hierarchical and centralized control system according to claim 1, characterized in that: The centralized controller and the device control layer of each subsystem of the microgrid realize data exchange through the communication gateway, and the communication gateway converts the communication protocol of the device control layer of each subsystem of the power grid into the communication protocol of the centralized controller system.

4. A microgrid hierarchical and centralized control system according to claim 1, characterized in that: It also includes a flexible power unit, and the flexible power unit exchanges data with the centralized controller via a communication gateway.

5. A microgrid hierarchical and centralized control system according to claim 1, characterized in that: In the equipment layer of each subsystem of the microgrid, the control logic, control algorithm, and safety protection of the control system are separated from the power setting value and the optimal target control value of the control system of each subsystem of the microgrid. The power setting value and the optimal target control value of the control system of each subsystem of the microgrid are set by the centralized control system; the real-time operating value of each subsystem of the microgrid is transmitted to the centralized control system via communication. The centralized control system calculates the optimal power control setting value and multi-target control value of each subsystem of the microgrid based on the real-time operating value of each subsystem of the microgrid and the energy dispatching information of the energy management layer, and writes them into the control system of each subsystem of the microgrid via communication.

6. A microgrid hierarchical and centralized control system according to claim 5, characterized in that: The centralized control system collects real-time data from each subsystem of the microgrid. When the real-time data from each subsystem of the microgrid exceeds the safety set value, the entire system is interlocked according to the set safety interlock procedure.

7. A microgrid hierarchical and centralized control system according to claim 3, characterized in that: When the communication protocol of the control system of each subsystem of the microgrid is inconsistent with the protocol of the centralized control system, the communication protocol conversion is realized through the communication gateway to match the communication protocol of the centralized control system.

8. A microgrid hierarchical and centralized control system according to claim 4, characterized in that: When there is a shared flexible power unit among the subsystem devices of the microgrid, the centralized control system allocates the power calculation value according to the power demand signal of each subsystem of the microgrid through the control program of the centralized controller of the centralized control layer and sends it to the shared flexible power unit, thereby realizing the coordinated control of the centralized control system, the control systems of each subsystem of the microgrid and the shared flexible power unit.

9. A microgrid hierarchical and centralized control method, characterized in that: A microgrid hierarchical and centralized control system applied to any one of claims 1-8.

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