CN211880096U

CN211880096U - Urban community full-direct-current micro-grid and control system thereof

Info

Publication number: CN211880096U
Application number: CN202020064276.7U
Authority: CN
Inventors: 肖彪; 叶磊; 刘智亮; 张威
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2020-01-13
Filing date: 2020-01-13
Publication date: 2020-11-06
Anticipated expiration: 2030-01-13

Abstract

The utility model provides a city community's full direct current microgrid and control system thereof, include: the methane fuel cell power generation system is connected with the community-level direct current bus, the community-level direct current bus is connected with the building-level direct current bus after passing through the building DC/DC converter, and the building-level direct current bus is connected with the household-level micro power grid. The utility model discloses electricity generation, distribution and power consumption process are full direct current, need not links such as contravariant, rectification, not only reduce the electric energy loss of netting such as photovoltaic, fuel cell, energy storage, also reduce the electric energy loss that direct current electrical apparatus inserted, can also make every user's reliability of power supply further improve to the different voltage level power of being convenient for and load access reduce energy storage system configuration capacity simultaneously, reduce the energy storage cost.

Description

Urban community full-direct-current micro-grid and control system thereof

Technical Field

The utility model relates to a little electric wire netting technical field, concretely relates to city community's full direct current little electric wire netting and control system thereof.

Background

With the development of the modern science and technology level and the improvement of the living standard of people, people buy more and more electrical equipment to improve the quality of life, electric power becomes indispensable energy of modern people, and more strict requirements are put forward on the electric energy quality, the power supply reliability and the energy efficiency of the electric power. At present, the centralized power generation, transmission and distribution mode widely used in the world has the problems of high construction cost, environmental pollution, large transmission loss, poor electric energy quality, low power supply reliability and the like, and news with large-scale power failure accidents is not rare.

Because distributed energy such as photovoltaic energy, fuel cells and the like are mostly direct current, digital products such as computers, mobile phones and the like use direct current, direct current electric energy is indirectly used in a plurality of electric appliances by using a direct current frequency conversion technology, but the existing power distribution network is alternating current, and a plurality of alternating current-direct current electric energy conversion links are inevitably existed in the middle of the power distribution network, so that energy loss is caused, and energy efficiency is reduced. At present, household appliances such as a direct current air conditioner, a direct current refrigerator, a direct current washing machine, a direct current electric cooker, a direct current fan, a direct current LED lamp, a direct current air purifier and the like serve thousands of households, so that a full direct current power distribution network is imperative to be built.

With the idea of energy conservation and environmental protection, the distributed renewable energy is rapidly developed, and the construction of the microgrid becomes the primary choice for local consumption of the distributed renewable energy and improvement of power supply reliability. The traditional micro-grid generally comprises power generation units and energy storage units such as wind power, photovoltaics, energy storage batteries and diesel generators, but for urban communities, the wind power does not have construction conditions, the photovoltaic installation site is limited, only depending on the top of a building, the installed power is far smaller than the power consumption load, the diesel generators have the problems of air pollution and noise, the large-capacity energy storage batteries can be configured, the current energy storage batteries are expensive and short in service life, the period is required to be changed, and the input cost is high. The fuel cell has the advantages of high efficiency, no noise and no pollution, and is the best choice for the urban community micro-grid power generation source. Because hydrogen is high in price and difficult to obtain, and public concerns about hydrogen safety are large, the acceptance degree is low, and the hydrogen fuel cell is not suitable for urban community application at present. And natural gas (methane) has a mature conveying system, is easy to accept by residents and is suitable for developing a methane fuel cell.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome the weak point among the prior art and provide a full direct current microgrid of city community and control system to methane fuel cell combines photovoltaic, energy storage system as main power generation source, is the direct current load power supply such as dc apparatus jointly, improves the power supply reliability.

The purpose of the utility model is realized through the following technical scheme: the utility model provides a full direct current little electric wire netting of city community, include: methane fuel cell power generation system, community level direct current bus and the little electric wire netting of building level of arbitrary quantity, building level little electric wire netting includes photovoltaic array, DC/DC photovoltaic converter, building DC/DC converter, building level direct current bus and the family of arbitrary quantity is with little electric wire netting, methane fuel cell power generation system connects community level direct current bus, photovoltaic array passes through DC/DC photovoltaic converter connects community level direct current bus, community level direct current bus passes through building DC/DC converter back-connection building level direct current bus, building level direct current bus connects the little electric wire netting of family class.

Further, the community full dc microgrid also includes: the system comprises a community energy storage system ESS, a community DC/DC energy storage converter, an AC/DC bidirectional grid-connected inverter and a grid-connected switch S1, wherein the community-level direct current bus is connected with the AC/DC bidirectional grid-connected inverter, the AC/DC bidirectional grid-connected inverter is connected with an external alternating current power grid through the grid-connected switch S1, and the community energy storage system ESS is connected with the community-level direct current bus through the community DC/DC energy storage converter.

Further, the building-level microgrid also comprises: building energy storage system ESS, building DC/DC energy storage converter, car charging pile, central air conditioner and building power supply master switch S2, building energy storage system ESS connects building DC/DC energy storage converter, building DC/DC energy storage converter passes through building power supply master switch S2 connects the level direct current bus of community, central air conditioner passes through building power supply master switch S2 and connects the level direct current bus of community, the car charging pile passes through building power supply master switch S2 and connects the level direct current bus of community.

Further, the household-scale microgrid comprises: the household energy storage system comprises a household DC/DC converter, a DC load, a household DC/DC energy storage converter, a household energy storage system ESS and a household power supply switch S3, wherein the DC load is connected with one end of the household power supply switch S3 through the household DC/DC converter or is directly connected with one end of the household power supply switch S3, the household energy storage system ESS is connected with one end of the household power supply switch S3 through the household DC/DC energy storage converter, and the other end of the household power supply switch S3 is connected with the building-level DC bus.

Further, the methane fuel cell power generation system comprises a natural gas storage tank, a first valve, a second valve, a third valve, a methane fuel cell, a DC/DC fuel cell DC converter, a natural gas input end and a household gas end, the natural gas storage tank is connected with one end of the third valve, the other end of the third valve is connected with the power supply end of the methane fuel cell, the common end of the third valve is connected with one end of the second valve, the other end of the second valve is connected with one end of the first valve, the public end is connected with a gas end for a user, the other end of the first valve is connected with a natural gas input end, the output end of the methane fuel cell is connected with the input end of the DC/DC fuel cell DC converter, the output end of the DC/DC fuel cell DC converter is connected with a community-level DC bus, and the common end of the DC/DC fuel cell DC converter is connected with the power supply end of the methane fuel cell.

The utility model also provides a control system of the full direct current little electric wire netting of urban community, the control system of the full direct current little electric wire netting of urban community is applied to above-mentioned arbitrary one the full direct current little electric wire netting of urban community, include:

the system comprises a full-direct-current microgrid community control system, a full-direct-current microgrid building control system and a full-direct-current microgrid household controller, wherein the full-direct-current microgrid community control system is used for controlling the methane fuel cell power generation system, a community Energy Storage System (ESS), a community DC/DC energy storage converter, an AC/DC bidirectional grid-connected inverter and a grid-connected switch S1, the full-direct-current microgrid building control system is used for controlling the building-level microgrid, and the full-direct-current microgrid household controller is used for controlling the household-level microgrid.

Further, the full dc microgrid community control system includes: the system comprises a computer server and a data concentration module, wherein the data concentration module comprises a plurality of communication interfaces, and the communication interfaces are respectively connected with the grid-connected switch S1, the AC/DC bidirectional grid-connected inverter, a control module of the community energy storage system ESS and a control module of the methane fuel cell power generation system.

Further, the full-direct-current micro-grid building control system comprises: the intelligent building energy storage system comprises a computer server and a data concentration module, wherein the data concentration module comprises a plurality of communication interfaces, and the communication interfaces are respectively connected with the building power supply main switch S2, the building DC/DC converter, the automobile charging pile, a control module of the building energy storage system ESS, the DC/DC photovoltaic converter and the central air conditioner.

Further, the all-direct-current microgrid home controller comprises: the household controller comprises a micro Central Processing Unit (CPU), any number of communication interfaces and user operation interfaces, wherein the full-direct-current microgrid household controller is connected with the household power supply switch S3, the household DC/DC energy storage converter, the household DC/DC converter and a control module of the household energy storage system ESS through the communication interfaces.

The utility model has the advantages that: the utility model provides a city community full direct current micro-grid and a control system thereof, the utility model discloses a city community full direct current micro-grid power generation, distribution and power utilization process is full direct current, links such as inversion and rectification are not needed, thereby not only reducing the power loss of the grid, such as photovoltaic, fuel cell and energy storage, but also reducing the power loss of the direct current electrical appliance; the micro-grid system is divided into three-layer structures including a community layer, a building layer and a user layer, and the power supply reliability of each user is further improved; three-level bus voltage is adopted, so that power supplies and loads with different voltage levels can be conveniently accessed; the methane fuel cell is used as a main power generation source, so that the configuration capacity of an energy storage system is reduced, and the energy storage cost is reduced.

Drawings

The invention is further described with the aid of the accompanying drawings, in which, however, the embodiments do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be derived from the following drawings without inventive effort.

Fig. 1 is a structural topological diagram of the full dc microgrid of the city community.

Fig. 2 is a structural topological diagram of the methane fuel cell power generation system of the full dc micro-grid in the city community.

Fig. 3 is a topological diagram of a control system of the full dc microgrid of the city community.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.

Embodiment 1, a city community full direct current microgrid.

As shown in fig. 1, the urban community full dc microgrid of the present embodiment includes: methane-fuel cell power generation system, community level direct current bus and the little electric wire netting of building level of arbitrary quantity, building level little electric wire netting includes photovoltaic array, DC/DC photovoltaic converter, building DC/DC converter, building level direct current bus and the family of arbitrary quantity is with little electric wire netting, methane-fuel cell power generation system connects community level direct current bus, photovoltaic array passes through connect DC/DC photovoltaic converter community level direct current bus, community level direct current bus passes through building DC/DC converter back connection building level direct current bus, building level direct current bus connects the little electric wire netting of family class.

The community full-direct-current microgrid further comprises: the system comprises a community energy storage system ESS, a community DC/DC energy storage converter, an AC/DC bidirectional grid-connected inverter and a grid-connected switch S1, wherein the community-level direct current bus is connected with the AC/DC bidirectional grid-connected inverter, the AC/DC bidirectional grid-connected inverter is connected with an external alternating current power grid through the grid-connected switch S1, and the community energy storage system ESS is connected with the community-level direct current bus through the community DC/DC energy storage converter.

The building DC/DC converter is a 750V-400VDC/DC converter and is used for converting 750V direct current into 400V direct current, and the community-level direct current bus is a 750V direct current bus and is used for providing 750V direct current.

When the external alternating current power grid supplies power normally, the grid-connected switch S1 is closed, and the community full-direct-current micro-grid takes the external alternating current power grid as a main power supply source. The power grid is rectified into 750V direct-current voltage through a bidirectional grid-connected inverter, an energy storage system in the community full-direct-current micro-grid is charged, direct-current loads such as direct-current electric appliances and charging piles are supplied with power, and at the moment, the methane fuel cell power generation system does not work. If the electric quantity of the energy storage system is sufficient and the power generation quantity of the photovoltaic power generation system is higher than the power load, the community full-direct-current micro-grid inverts the redundant electric quantity through the bidirectional grid-connected inverter and feeds back the redundant electric quantity to the power grid.

The community full-direct-current micro-grid system is connected with an external alternating-current power grid through an AC/DC bidirectional grid-connected inverter and a grid-connected switch S1, when the power supply of the external alternating-current power grid is abnormal, the grid-connected switch S1 is disconnected, the community full-direct-current micro-grid is operated in an isolated island mode, and at the moment, the methane fuel cell power generation system works to provide power for the community full-direct-current micro-grid system. In the starting process of the methane fuel cell, the community energy storage system ESS supplies power to each direct current load in the community full direct current microgrid and supplies power to the methane fuel cell FC in an auxiliary mode.

The community energy storage system ESS comprises but is not limited to an energy storage battery (such as a lithium battery, a storage battery and the like), a super capacitor, flywheel energy storage, compressed air and a combination thereof, and is provided with a BMS (battery management system) for detecting the single voltage, the temperature and the state of charge SOC of the community energy storage system ESS.

The community energy storage system ESS is connected to the 750V direct current bus through the DC/DC energy storage converter, and the DC/DC energy storage converter regulates the voltage of the community energy storage system ESS to be matched with the voltage of the 750V direct current bus and controls the charging and discharging of the community energy storage system ESS.

As shown in fig. 2, the methane fuel cell power generation system includes: natural gas holder, valve 1, valve 2, valve 3, methane fuel cell FC, DC/DC fuel cell direct current converter, natural gas input and resident family gas end, natural gas tank connection the one end of valve 3, the other end of valve 3 is connected methane fuel cell FC's feed end and common port are connected the one end of valve 2, the other end of valve 2 is connected the resident family gas end is connected to the one end and the common port of valve 1, the natural gas input is connected to the other end of first valve, the output of methane fuel cell FC is connected DC/DC fuel cell direct current converter's input, 750V direct current bus and common port are connected to DC/DC fuel cell direct current converter's output the feed end of methane fuel cell.

The natural gas storage tank is used for storing natural gas (methane), the methane is provided by connecting the valve 3 with the methane fuel cell when the gas supply is stopped, and the natural gas can be provided for a resident by the valve 3 and the valve 2 when the resident needs to use the natural gas, and meanwhile, the valve 1 is closed. It should be noted that "connected" in the present embodiment includes direct or indirect (the connection path includes other components or devices) connection.

An external natural gas pipeline supplies gas to residents through a valve 1, is connected to a methane fuel cell FC through the valve 1 and a valve 2, directly supplies methane to the fuel cell, is connected to a natural gas storage tank through the valve 1, the valve 2 and a valve 3, and charges the gas storage tank.

The methane fuel cell FC is connected to the input end of the DC/DC fuel cell DC converter, and the methane fuel cell FC converts chemical energy in methane and oxygen into electric energy, and the electric energy is converted into 750V direct current through the DC/DC fuel cell DC converter and is output to a 750V direct current bus. The methane fuel cell FC takes electricity from a 750V dc bus for powering auxiliary systems.

The DC/DC fuel cell DC converter regulates the output voltage of the methane fuel cell FC to the same voltage as the 750V DC bus in a voltage reduction or voltage boosting mode.

Building-level microgrid takes a building as a unit, a community full-direct-current microgrid comprises a Photovoltaic (PV) array, a DC/DC photovoltaic converter, a building DC/DC converter, a building-level direct-current bus, any number of household-level microgrids, a building energy storage system ESS, a building DC/DC energy storage converter, an automobile charging pile, a central air conditioner and a building power supply master switch S2, the PV array (PV) is connected with the community-level direct-current bus through the DC/DC photovoltaic converter, the community-level direct-current bus is connected with the building-level direct-current bus through the building DC/DC converter, the building-level direct-current bus is connected with the household-level microgrid, the building DC/DC energy storage converter is connected with the community-level direct-current bus through the building power supply master switch S2, and the central air conditioner is connected with the community-level direct-current bus through the building power supply master switch S2, the automobile charging pile is connected with the community-level direct-current bus through the building power supply main switch S2.

High-power direct current loads such as a direct current central air conditioner and an automobile charging pile are connected to a 750V direct current bus, a Photovoltaic (PV) array is installed on the roof of a building and is connected to the 750V direct current bus through a DC/DC photovoltaic converter, and an ESS of a building energy storage system is connected to the 750V direct current bus through an energy storage converter; the 750V direct current bus is connected to the input end of a 750V-400VDC/DC converter, and a 400V building-level direct current bus is obtained after voltage reduction; and the 400V direct current bus is connected into each household in the building and is connected with the household-level micro-grid.

Household-level micro-grids take households as units, and one building-level micro-grid comprises: the household energy storage system comprises a 400V-48V household DC/DC converter, a direct current load, a household DC/DC energy storage converter, a household energy storage system ESS and a household power supply switch S3, wherein the direct current load is connected with one end of the household power supply switch S3 through the household DC/DC converter or is directly connected with one end of the household power supply switch S3, the household energy storage system ESS is connected with one end of the household power supply switch S3 through the household DC/DC energy storage converter, and the other end of the household power supply switch S3 is connected with the building-level direct current bus.

The user-used secondary microgrid is connected with other user-used secondary microgrids through a household power supply switch S3 to a 400V direct current bus. When the household power supply switch S3 is closed, the household micro-grid acquires external 400V direct current bus electric energy and charges the household energy storage system ESS; when the household power supply switch S3 is turned off, the household energy storage system ESS serves as the sole power supply of the household micro-grid to supply power to the direct current load.

A 400V direct current load such as a direct current electric appliance such as a direct current air conditioner, a direct current refrigerator and the like is connected to a 400V direct current bus to get electricity; the energy storage system ESS is connected to a 400V direct current bus through a household DC/DC energy storage converter and is used as a household standby power supply; the 400V direct current bus is connected into a 400V-48V converter and is output to the 48V direct current bus through voltage reduction conversion; A48V direct current load such as a direct current fan, a direct current LED lamp and other direct current electrical appliances are connected to the 48V direct current bus.

When the power supply of the external alternating current power grid of the urban community full-direct current micro-grid system is normal, the external alternating current power grid power supply and the electric energy of the photovoltaic power generation system are preferentially used, and sufficient electric quantity is maintained by charging the energy storage system ESS; when the power supply of the external alternating current power grid is abnormal, the electric energy of a photovoltaic and methane fuel cell power generation system is preferentially used, and the energy storage system ESS plays a role in auxiliary regulation and maintains sufficient electric quantity; the energy storage system ESS is used as the primary power source only when the natural gas (methane) is exhausted. When the external alternating current power grid is powered off and the natural gas is used up, the electric energy of the community energy storage system is preferentially used, the electric energy of the building energy storage system is used, and the electric energy of the household energy storage system is used finally.

The utility model discloses a city community full direct current microgrid, electricity generation, distribution and power consumption process are full direct current, need not links such as contravariant, rectification, not only reduce the electric energy loss of networking such as photovoltaic, fuel cell, energy storage, also reduce the electric energy loss of direct current electrical apparatus access; the micro-grid system is divided into three-layer structures including a community layer, a building layer and a user layer, and the power supply reliability of each user is further improved; three-level bus voltage is adopted, so that power supplies and loads with different voltage levels can be conveniently accessed; the methane fuel cell is used as a main power generation source, so that the configuration capacity of an energy storage system is reduced, and the energy storage cost is reduced.

Embodiment 2, a control system of full direct current little electric wire netting of city community.

This embodiment provides a control system of full direct current little electric wire netting of urban community, the control system of full direct current little electric wire netting of urban community is applied to the full direct current little electric wire netting of urban community of embodiment 1, include:

The all-direct-current microgrid household controller is a user-level microgrid control center and comprises a micro Central Processing Unit (CPU), one or more communication interfaces and a user operation interface. The household controller is connected with the household power supply switch S3, the 400V-48VDC/DC converter and the control module of the household energy storage system ESS through a communication interface, and the communication mode is bus communication, such as a CAN bus of the embodiment. The household controller obtains bus voltage and current from the household power supply switch S3, calculates the total load power of the user, and controls the switch S3 to be opened and closed; the household controller acquires the 48V bus voltage, current and power and the operation state of the converter such as normal and fault information from the 400V-48V converter and controls the converter to start and stop; the household controller obtains the residual electric quantity, the charging and discharging state, the charging and discharging power, the fault information and the like of the household energy storage system ESS from a control module of the household energy storage system ESS, and sending communication command for controlling charging and discharging of the household energy storage system ESS, the control module of the household energy storage system ESS is connected with the battery management system BMS of the household energy storage system ESS and the household DC/DC energy storage converter through internal bus communication, the battery management system BMS is provided with voltage and temperature sensors and can detect the information of single voltage, temperature, electric quantity SOC and the like of the household energy storage system ESS and transmit the information to the control module of the household energy storage system ESS, the household DC/DC energy storage converter is a bidirectional DC converter and controls charging and discharging of the household energy storage system ESS, and transmitting the charging and discharging power, the running state, the fault information and the like to a control module of the household energy storage system ESS, and receiving a charging and discharging control command sent by the control module of the household energy storage system ESS.

The household controller is connected with the building control system through a communication interface, the communication mode is ethernet communication, wireless communication or bus communication, in the embodiment, the CAN bus communication is used, information such as total load power, household Energy Storage System (ESS) electric quantity and the like is transmitted to the building control system, and information or a control command sent by the building control system is received. The user operation interface is a touch screen, or a display screen and a button, in this embodiment, the touch screen displays operation state information of the user microgrid, such as voltage, current, power, electric quantity of the user energy storage system ESS, fault information, and the like, and receives a user operation touch screen command.

The micro central processing unit CPU receives data of the communication interface, calculates running state data of the household micro-grid, such as load power, transmits or displays the information on the touch screen through the communication interface, receives a control command of the touch screen, and sends corresponding information or the control command through the communication interface after logic processing.

The household controller controls the user microgrid to preferentially use a 400V direct-current bus power supply, and when the external power supply is powered off, the controller controls the power supply switch S3 to be switched off and controls the user ESS to discharge; when the external power supply is powered on, the household controller controls the power supply switch S3 to be closed, if the energy storage system ESS for the household is detected to be insufficient in electric quantity, the energy storage system ESS for the household is controlled to be charged, and the DC/DC energy storage converter for the household is stopped until the electric quantity is full.

The full-direct-current micro-grid building control system is the core of a building layer micro-grid and comprises a computer server and a data concentration module. The data concentration module comprises a plurality of communication interfaces which are respectively connected with a building power supply main switch S2, a 750V-400V converter, a charging pile, a building energy storage system control module, a photovoltaic converter and a central air conditioner, the communication mode is CAN bus communication, and meanwhile, the data concentration module is also connected with a plurality of household controllers, the communication mode is bus communication, Ethernet communication or wireless communication, and the communication mode is CAN bus communication in the embodiment.

The data concentration module collects all communication data and sends the collected data to the computer server, and sends the communication data from the computer server to the corresponding communication interface. The building control system obtains data such as voltage, current of the community-level direct current bus from the building power supply main switch S2, and controls the opening and closing of the building power supply main switch S2. The building control system acquires voltage, current, power, operating status and fault information from the 750V-400VDC/DC converter and controls the operation and stop of the 750V-400VDC/DC converter.

And the building control system acquires photovoltaic power generation power from the DC/DC photovoltaic converter and controls the DC/DC photovoltaic converter to operate and stop. The building control system acquires the residual electric quantity, the charging and discharging state, the charging and discharging power, the fault information and the like of the building Energy Storage System (ESS) from a control module of the building Energy Storage System (ESS), and sends a charging and discharging control command of the building Energy Storage System (ESS); the control module of the building energy storage system ESS is connected with a battery management system BMS of the building energy storage system ESS and a building DC/DC energy storage converter through bus communication, and the function of the control module is the same as that of the control module of the household energy storage system ESS.

And the building control system acquires load power from the charging pile and the central air conditioner. The computer server obtains all operation state data of the building-level microgrid, calculates total load power and total power generation power in the microgrid, executes a responsive control strategy and logic, displays summarized data and operation state information on a computer server interface, can receive control commands of operators, and transmits the data and the control commands to the data concentration module.

The building control system controls a building-level microgrid to preferentially use a photovoltaic power supply and controls a DC/DC photovoltaic converter to operate at the maximum power, if the photovoltaic PV power generation power is greater than the total load power of a charging pile, a central air conditioner and each household microgrid, the building energy storage system ESS is started to charge, after the building energy storage system ESS is full, redundant electric energy is output through a building power supply main switch S2, and information is sent to a full-direct-current microgrid community control system; if the photovoltaic PV power generation power is less than the total load power, the required electric energy is input through a building power supply main switch S2, and the building energy storage system ESS is charged until the building energy storage system ESS is fully charged.

If the external bus of the building is powered off, the building control system controls a building power supply main switch S2 to be switched off, the photovoltaic PV is preferentially used for power generation, and if the building energy storage system ESS is full and the power generation power of the photovoltaic PV is greater than the total load, the DC/DC photovoltaic converter is controlled to limit the power output, so that the source load power is balanced; if the electricity quantity of the building energy storage system ESS is insufficient and the photovoltaic PV power generation power is larger than the total load, controlling the building energy storage system ESS to charge; if the photovoltaic PV power generation power is insufficient, controlling the ESS of the building energy storage system to discharge; and if the photovoltaic PV power generation power is 0 and the ESS of the building energy storage system is insufficient at night, controlling all the household micro-grids to be disconnected from the 400V bus, and stopping the building-level micro-grid.

The full-direct-current microgrid community control system is a control core of a community-level microgrid and comprises a computer server and a data concentration module. The data concentration module comprises a plurality of communication interfaces which are respectively connected with a grid-connected switch S1, an AC/DC bidirectional grid-connected inverter, a control module of a community energy storage system ESS and a control module of a methane fuel cell power generation system, the communication mode is CAN bus communication, and is also connected with a plurality of building control systems, the communication mode is bus communication, Ethernet communication or wireless communication, and the embodiment takes CAN bus communication as an example for description.

The data concentration module collects all communication data and sends the collected data to the computer server, and sends the communication data from the computer server to the corresponding communication interface. The community control system detects data such as voltage and current of a power grid at the grid-connected switch S1 and controls the on and off of the grid-connected switch S1, namely controls the grid connection and island operation of the community full-direct-current micro-grid. The community control system obtains the voltage of a bus, the running state of the AC/DC bidirectional inverter, fault information and the like from the AC/DC bidirectional grid-connected inverter and controls the AC/DC bidirectional inverter to start and stop, invert and rectify.

The community control system acquires the residual electric quantity, the charge-discharge state, the charge-discharge power, the fault information and the like of the community energy storage system from a control module of an ESS of the community energy storage system and sends a charge-discharge control command of the ESS of the community energy storage system; and the control module of the community energy storage system ESS is connected with the community energy storage system ESS and the DC/DC energy storage converter through CAN bus communication, and the function of the control module is the same as that of the control module of the building energy storage system ESS.

The community control system acquires information such as natural gas supply state, pressure, temperature and allowance of the gas storage tank, operation state data such as voltage, current, temperature and gas flow of the methane fuel cell FC, operation state and fault information of the DC/DC fuel cell DC converter and the like from a control module of the methane fuel cell power generation system, and controls commands to control operation and stop of the fuel cell power generation system, charge/discharge of the gas storage tank and supply gas to users.

The control module of the fuel cell power generation system is in communication connection with the natural gas valve, the gas storage tank, the methane fuel cell FC and the DC/DC fuel cell DC converter, and the communication mode is CAN bus communication. The valve 1, the valve 2 and the valve 3 can detect pressure and temperature data at two ends of the valve, transmit the data and the on-off state of the data to a control module of the fuel cell power generation system through communication, and receive a command of the control module of the fuel cell power generation system to open or close the valve, so that the functions of inflating a gas storage tank, directly supplying external natural gas to the fuel cell, supplying gas to the fuel cell by the gas storage tank or supplying gas to a user by the gas storage tank are realized.

The gas storage tank is internally provided with a pressure sensor and a temperature sensor, detects the pressure and the temperature of the natural gas in the pipe, and transmits the pressure and temperature data to a control module of the fuel cell power generation system for calculating the natural gas allowance. The methane fuel cell FC comprises a fuel cell stack, a fuel cell auxiliary system and a fuel cell controller, wherein the stack converts chemical energy in natural gas and oxygen into electric energy, the auxiliary system provides the natural gas, the oxygen and a heat dissipation function for the stack, the controller comprises a voltage sensor, a current sensor and a temperature sensor, detects operating state data of the fuel cell such as voltage, current and temperature and controls the auxiliary system to start/stop the fuel cell, and the fuel cell controller transmits the operating state data of the fuel cell to a fuel cell power generation system control module in a communication mode and receives a fuel cell operation and stop command of the control module. The fuel cell dc converter communicates converter operating state data and fault information to a control module of the fuel cell power generation system and receives an operation or stop command of the control module of the fuel cell power generation system.

The computer server obtains all operation state data of the community layer microgrid, calculates total load power and total power generation power in the microgrid, executes a control strategy and logic of response, displays summarized data and operation state information on a computer server interface, can receive control commands of operators, and transmits the data and the control commands to the data concentration module.

When the full-direct-current microgrid community control system detects that a power grid operates normally, a grid-connected switch S1 is controlled to be closed and an AC/DC bidirectional grid-connected inverter is started, when the total power generation power in a community-level microgrid is greater than the total load power, if the electric quantity of an ESS of a community energy storage system is insufficient, the ESS of the community energy storage system is controlled to be charged, if the electric quantity of the ESS of the community energy storage system is sufficient, the AC/DC bidirectional grid-connected inverter is controlled to be in an inversion operation state, redundant electric quantity is output to the power grid, and when the total power generation power is less than the total load power, the AC/DC bidirectional grid-connected inverter is controlled. When the abnormal operation of the power grid is detected, the grid-connected switch S1 is controlled to be switched off, the AC/DC bidirectional grid-connected inverter stops operating, the community-level micro-power grid operates in an isolated island mode, if the total generated power is larger than the total load power, if the electricity quantity of the community energy storage system ESS is insufficient, the community energy storage system ESS is controlled to be charged, and if the electricity quantity of the community energy storage system ESS is sufficient, the generated power of a fuel cell power generation system or a photovoltaic power generation system is reduced; and if the total power generation power is less than the total load power, controlling the discharging of the community energy storage system ESS, starting the methane fuel cell power generation system to operate, controlling the community energy storage system ESS to be charged to be full after the fuel cell power generation system is started, and controlling the community energy storage system ESS to discharge when the gas source of the fuel cell is consumed.

When the community control system detects that the external natural gas is supplied normally, the control valve 1 is opened, if the methane fuel cell power generation system is detected to be started, the control valve 2 is opened to supply gas to the fuel cell, and if the gas storage amount of the gas storage tank is detected to be insufficient, the control valve 2 and the valve 3 are opened to charge the gas storage tank; when the community control system detects that the supply of external natural gas is cut off, the control valve 1 is closed, if the methane fuel cell power generation system is started, the control valve 3 is opened, the valve 2 is closed, the gas storage tank supplies gas for the fuel cell, and if gas is required to be supplied for a user, the control valve 2 and the valve 3 are opened, and the gas storage tank supplies gas for the user.

It should be finally noted that the above embodiments are only intended to illustrate the technical solutions of the present invention, and not to limit the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention can be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. The utility model provides an all direct current microgrid of city community which characterized in that, all direct current microgrid of community includes: methane fuel cell power generation system, community level direct current bus and the little electric wire netting of building level of arbitrary quantity, building level little electric wire netting includes photovoltaic array, DC/DC photovoltaic converter, building DC/DC converter, building level direct current bus and the family of arbitrary quantity is with little electric wire netting, methane fuel cell power generation system connects community level direct current bus, photovoltaic array passes through DC/DC photovoltaic converter connects community level direct current bus, community level direct current bus passes through building DC/DC converter back-connection building level direct current bus, building level direct current bus connects the little electric wire netting of family class.

2. The city community all-dc microgrid of claim 1, wherein the community all-dc microgrid further comprises: the system comprises a community energy storage system ESS, a community DC/DC energy storage converter, an AC/DC bidirectional grid-connected inverter and a grid-connected switch S1, wherein the community-level direct current bus is connected with the AC/DC bidirectional grid-connected inverter, the AC/DC bidirectional grid-connected inverter is connected with an external alternating current power grid through the grid-connected switch S1, and the community energy storage system ESS is connected with the community-level direct current bus through the community DC/DC energy storage converter.

3. The city community all-dc microgrid of claim 1, wherein said building level microgrid further comprises: building energy storage system ESS, building DC/DC energy storage converter, car charging pile, central air conditioner and building power supply master switch S2, building energy storage system ESS connects building DC/DC energy storage converter, building DC/DC energy storage converter passes through building power supply master switch S2 connects the level direct current bus of community, central air conditioner passes through building power supply master switch S2 and connects the level direct current bus of community, the car charging pile passes through building power supply master switch S2 and connects the level direct current bus of community.

4. The city community full dc microgrid of claim 1, wherein said household microgrid comprises: the household energy storage system comprises a household DC/DC converter, a DC load, a household DC/DC energy storage converter, a household energy storage system ESS and a household power supply switch S3, wherein the DC load is connected with one end of the household power supply switch S3 through the household DC/DC converter or is directly connected with one end of the household power supply switch S3, the household energy storage system ESS is connected with one end of the household power supply switch S3 through the household DC/DC energy storage converter, and the other end of the household power supply switch S3 is connected with the building-level DC bus.

5. The urban community full direct-current microgrid according to claim 1, wherein the methane fuel cell power generation system comprises a natural gas storage tank, a first valve, a second valve, a third valve, a methane fuel cell, a DC/DC fuel cell direct-current converter, a natural gas input end and a household gas end, the natural gas storage tank is connected with one end of the third valve, the other end of the third valve is connected with a power supply end of the methane fuel cell and a public end of the third valve is connected with one end of the second valve, the other end of the second valve is connected with one end of the first valve and a public end of the second valve is connected with a household gas end, the other end of the first valve is connected with the natural gas input end, an output end of the methane fuel cell is connected with an input end of the DC/DC fuel cell direct-current converter, an output end of the DC/DC fuel cell direct-current converter is connected with a community-level direct-current bus and a public end of the DC/ The power supply terminal of the battery.

6. A control system of an urban community full-direct-current microgrid is characterized in that the control system of the urban community full-direct-current microgrid is applied to the urban community full-direct-current microgrid according to any one of claims 1 to 5.

7. The control system of the city community full-direct-current micro-grid according to claim 6, comprising: the system comprises a full-direct-current microgrid community control system, a full-direct-current microgrid building control system and a full-direct-current microgrid household controller, wherein the full-direct-current microgrid community control system is used for controlling a methane fuel cell power generation system, a community Energy Storage System (ESS), a community DC/DC energy storage converter, an AC/DC bidirectional grid-connected inverter and a grid-connected switch S1, the full-direct-current microgrid building control system is used for controlling a building Energy Storage System (ESS), a building DC/DC energy storage converter, an automobile charging pile, a central air conditioner and a building power supply general switch S2 of a building-level microgrid, and the full-direct-current microgrid household controller is used for controlling a household DC/DC converter, a direct-current load, a household DC/DC energy storage converter, a household Energy Storage System (ESS) and a household power supply switch S3 of the household microgrid.

8. The control system of the city community full-direct-current microgrid according to claim 7, wherein the full-direct-current microgrid community control system comprises: the system comprises a computer server and a data concentration module, wherein the data concentration module comprises a plurality of communication interfaces, and the communication interfaces are respectively connected with the grid-connected switch S1, the AC/DC bidirectional grid-connected inverter, a control module of the community energy storage system ESS and a control module of the methane fuel cell power generation system.

9. The system of claim 7, wherein the system comprises: the intelligent building energy storage system comprises a computer server and a data concentration module, wherein the data concentration module comprises a plurality of communication interfaces, and the communication interfaces are respectively connected with the building power supply main switch S2, the building DC/DC converter, the automobile charging pile, a control module of the building energy storage system ESS, the DC/DC photovoltaic converter and the central air conditioner.

10. The system as claimed in claim 7, wherein the full dc microgrid home controller comprises: the household controller comprises a micro Central Processing Unit (CPU), any number of communication interfaces and user operation interfaces, wherein the full-direct-current microgrid household controller is connected with the household power supply switch S3, the household DC/DC energy storage converter, the household DC/DC converter and a control module of the household energy storage system ESS through the communication interfaces.