A microgrid hierarchical and centralized control method and system

Abstract

The present invention relates to the field of microgrids and discloses a microgrid hierarchical and centralized control method and system. The microgrid hierarchical control structure includes a zeroth layer, an equipment layer of each subsystem of the microgrid; a first layer, a control layer of the equipment of each subsystem of the microgrid, which completes the equipment-level control of each subsystem of the microgrid; a second layer, an energy management layer, which regulates power and voltage through control signals sent by the first layer to achieve power balance and microgrid voltage stability; a third layer, an operation and energy debugging layer, which regulates energy production scheduling instructions of each subsystem of the microgrid as energy instructions of the second layer, including a centralized control system, wherein the centralized control system includes multiple centralized controllers, and the multiple centralized controllers have inter-station communication functions for centralized control of the entire system; the present invention realizes the power control of the entire subsystem of the microgrid and the real-time control function of the multi-objective system, thereby improving the control stability of the microgrid system.

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 in the existing technical architecture constitute the first control layer. These controllers are independent of each other, making it difficult to achieve flexible control of shared power units across multiple systems and real-time control of multi-objective control systems. The subsystems within the microgrid are primarily coordinated through the energy dispatch and management layers, resulting in low real-time control and significant time delays. With the development of microgrid technology, each subsystem within the microgrid adopts an independent control principle, making it difficult to achieve flexible control of shared power units with existing technology. The control objectives of the flexible power distribution layer, device control layer, and energy management layer of each subsystem in the microgrid are inconsistent, making it difficult to achieve multi-objective control of each subsystem in the microgrid with existing technology. The real-time operating parameters and demand information of the coordinated control of each subsystem in existing technology require information exchange between the device control layer, the energy management layer, the energy dispatch layer, the energy management layer, and the device control layer. This results in poor real-time performance and makes it difficult to meet the real-time requirements of coordinated control for applications with high real-time control requirements.

[0004] With the development of microgrid technology, flexible control of the power units of the three subsystems, such as integrated photovoltaic, energy storage, and charging systems consisting of new energy vehicle charging stations, energy storage systems, and photovoltaic systems, has become impossible. In more diverse microgrid application scenarios, such as commercial microgrid systems for hotels and office buildings, which combine photovoltaic systems, energy storage systems, and all-DC air conditioning systems, as well as industrial microgrids composed of photovoltaic systems, wind power generation systems, energy storage systems, all-DC compression systems, cooling systems, and thermal storage systems, shared power units are involved. Existing low-level control systems, consisting of multiple subsystem controllers, are unable to achieve flexible control of shared power units across multiple systems, real-time control of multi-objective control systems, or real-time centralized control of distributed power sources. Existing technologies, due to the relative independence of each subsystem and its own safety protection system, primarily rely on the third-tier operations management and energy dispatch system for coordinated control of the entire microgrid, making it difficult to achieve the real-time safety interlocking protection requirements of the entire microgrid system. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology 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 signals sent by the first layer to achieve power balance and microgrid voltage stability; 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, 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 each subsystem of the microgrid also implement 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.

[0009] Preferably, the centralized controller and the device control layer of each subsystem of the microgrid realize data interaction 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 further comprises 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. 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 scheduling 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 program 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, the centralized control system performs safety interlocking of the entire system according to a set safety interlocking program.

[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 the 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 each subsystem 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 according to any one of claims 1 to 8.

[0016] The beneficial effects of the present invention are: the present invention realizes the power control of the entire 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 of 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 among subsystems, thereby saving the investment cost of the power unit.

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

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

[0020] Figure 1 This 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 will be further described in detail below with reference to 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 with reference to 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 signals sent by the first layer to achieve power balance and microgrid voltage stability; 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, 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 implement 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.

[0029] The centralized controller and the device control layer of each subsystem of the microgrid realize data interaction 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 exchanges data with the centralized controller through a communication gateway.

[0031] In the device 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 values ​​of each subsystem of the microgrid are 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 values ​​of each subsystem of the microgrid and the energy scheduling 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 collected from each subsystem of the microgrid exceeds the safety set value, the entire system will be interlocked according to the set safety interlock program.

[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 is characterized by being applied to the aforementioned microgrid hierarchical and centralized control system.

[0036] Specifically, the underlying control system of a microgrid is comprised of various subsystems. Each subsystem has distinct control objectives, control principles, response times, and control quality, making centralized control of these subsystems difficult to achieve. Each subsystem belongs to a different industry and is integrated by different equipment manufacturers. The control system is highly integrated with the equipment, and the operational quality and safety of the equipment are closely tied to the subsystem's control system. This makes it difficult to separate the equipment from 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 to the traditional hierarchical control system. The centralized control system 300 includes at least one or more centralized controllers. Inter-station communication can be implemented between the multiple centralized controllers to achieve centralized control functions for the entire system.

[0039] The centralized controller and the control systems 400 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 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] In the present invention, the control logic, control algorithms, and safety protection functions of each subsystem's control system 400 within the device layer 600 of each subsystem are separated from the power setting value and the optimal target control value of each subsystem's control system 400. The power control setting value and the optimal target control value of each subsystem's control system 400 are determined by the centralized control system 300. The real-time operating values ​​of each subsystem's control system 400 are transmitted to the centralized control system 300 via communication. The centralized control system 300 calculates the optimal power control setting value and multi-target control value for each subsystem's control system 400 based on the collected real-time operating values ​​of each subsystem's control system 400, and writes these values ​​to each subsystem's control system 400 via communication. This achieves the separation of power control and multi-target real-time control of each subsystem's control system 400, with the centralized control system 300 performing both.

[0043] Optionally, any or all of the power control and multi-objective system real-time control functions of the control system 400 of each subsystem 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 protocols of the control systems 400 of each subsystem are inconsistent with the centralized control system 300, communication protocol conversion software can be used in the centralized control system 300 to convert the communication protocols of the control systems 400 of each subsystem into the communication protocol of the centralized control system.

[0047] Optionally, data interaction between the control system 400 of each subsystem and the centralized control system 300 may be achieved through hard wiring.

[0048] The collaborative control and real-time performance of the control systems 400 of each subsystem and the centralized control system 300 of the present invention solve the real-time problem by adopting direct communication between the control systems 400 of each subsystem and the centralized control system 300, and the centralized controller realizes the collaborative control problem according to the collaborative control algorithm of each subsystem 300.

[0049] When a shared flexible power unit 500 exists 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 safety interlock protection requirements of the entire 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, thereby achieving the real-time safety interlock protection requirements of the entire 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 clearer, the following 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 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, etc. Other communication protocols not listed can also be used.

[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 input cards (DI), digital output cards (DO), model input cards (AI), and model 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 communication protocol conversion gateway software to implement communication protocol conversion within the controller. Gateway software can be KepWar, Ifix, etc., or it can be developed in a high-level language such as C++, C#, or JAVA to implement communication protocol conversion within 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 system 400 of each subsystem can be selected ,as 50ms, 100ms, 200ms, 500ms, etc. to meet the real-time ,requirements of 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 system 300 performs flexible power distribution calculation based on the read data, and transmits the output instruction 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 instruction. 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 is a shared unit of the energy storage subsystem and the charging station subsystem. The control parameters (charging power, charging voltage, charging current, charging capacity, SOC, etc.) of the two subsystems are different. To achieve real-time control of the multi-objective system of the two subsystems, the centralized control system collects the demand data of each subsystem and communicates the multi-objective parameters to the shared flexible power unit 500 in real time to realize the real-time control function 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, preventing the expansion of the accident and realizing the safety protection function of the entire microgrid system.

[0064] The foregoing description is merely 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 construed as excluding other embodiments. Rather, the present invention 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 techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.

Claims

1. A hierarchical and centralized control system for a microgrid. The hierarchical control structure of the microgrid includes the zeroth layer, the device layer of each subsystem of the microgrid; the first layer, the control layer of each subsystem of the microgrid, which completes the device-level control of each subsystem of the microgrid; the second layer, the energy management layer, which regulates power and voltage through the control signals sent by the first layer to achieve power balance and microgrid voltage stability; 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 exchange 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; 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 flexible power units of two or more microgrid subsystems; In the device 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 scheduling information of the energy management layer, and writes them into the control system of each subsystem of the microgrid via communication; When flexible power units exist between the subsystem devices of a microgrid, the centralized control system allocates power calculation values ​​according to the power demand signals of each subsystem of the microgrid through the control program of the centralized controller of the centralized control layer and sends them to the flexible power units, thereby realizing coordinated control of the centralized control system, the control systems of each subsystem of the microgrid, and the flexible power units.

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 implement 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.

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 interaction 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 through a communication gateway.

5. A microgrid hierarchical and centralized control system according to claim 4, characterized in that: The centralized control system collects real-time data from each subsystem of the microgrid. When the real-time data collected from each subsystem of the microgrid exceeds the safety set value, the entire system will be interlocked according to the set safety interlock program.

6. A microgrid hierarchical and centralized control system according to claim 1, 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.

7. A microgrid hierarchical and centralized control method, characterized in that: A microgrid hierarchical and centralized control system applied to any one of claims 1-6.

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