CN111953016B - Mobile multi-energy micro-grid control method and system - Google Patents

Mobile multi-energy micro-grid control method and system Download PDF

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Publication number
CN111953016B
CN111953016B CN202010729461.8A CN202010729461A CN111953016B CN 111953016 B CN111953016 B CN 111953016B CN 202010729461 A CN202010729461 A CN 202010729461A CN 111953016 B CN111953016 B CN 111953016B
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load
generator set
power
max
soc
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CN111953016A (en
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王建
陈金柯
尹必峰
贾和坤
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Jiangsu University
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Jiangsu University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/14—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/30—The power source being a fuel cell
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2310/00—The network for supplying or distributing electric power characterised by its spatial reach or by the load
    • H02J2310/50—The network for supplying or distributing electric power characterised by its spatial reach or by the load for selectively controlling the operation of the loads
    • H02J2310/56—The network for supplying or distributing electric power characterised by its spatial reach or by the load for selectively controlling the operation of the loads characterised by the condition upon which the selective controlling is based
    • H02J2310/58—The condition being electrical
    • H02J2310/60—Limiting power consumption in the network or in one section of the network, e.g. load shedding or peak shaving
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • Y02B70/3225—Demand response systems, e.g. load shedding, peak shaving
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E70/00—Other energy conversion or management systems reducing GHG emissions
    • Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/20—End-user application control systems
    • Y04S20/222—Demand response systems, e.g. load shedding, peak shaving

Abstract

The invention discloses a mobile multi-energy micro-grid control method and a system, wherein the mobile multi-energy micro-grid control method comprises the steps that firstly, a storage battery or a diesel engine generator set is independently started to serve as a main power supply according to the state of charge (SOC) of the storage battery; after the micro-grid system is started, the fuel cell generator set starts to work, if the fuel cell generator set is stable, the fuel cell generator set is used as a main power supply of the micro-grid system, and in the second stage, the photovoltaic cell generator set, the fuel cell generator set, the storage battery and the storage battery are mutually combined to generate power so as to meet load demand power P load The method comprises the steps of carrying out a first treatment on the surface of the If the fuel cell generator set is unstable, the photovoltaic cell generator set, the storage battery, the diesel engine generator set and the diesel engine generator set are mutually combined to generate power so as to meet the load demand power P load . The invention can realize the advantages of combining renewable energy and a micro-grid system and realize the utilization of movable micro-grid energy.

Description

Mobile multi-energy micro-grid control method and system
Technical Field
The invention relates to the technical field of power supply equipment, in particular to a mobile multi-energy micro-grid control method and system.
Background
In the utilization of renewable energy power generation, wind power, photovoltaic power generation and the like are influenced by meteorological factors, the renewable energy power generation device has intermittent and random fluctuation, the output power fluctuation is caused, the power grid is not negligibly negatively influenced, and the power fluctuation of the renewable energy power generation due to the meteorological factors can be stabilized by designing the energy storage device.
Micro-Grid (Micro-Grid), which is a small power generation and distribution system, can be used for realizing reliable supply of various energy forms with different loads, and is an effective way for realizing an active power distribution network. Since the direct current micro-grid system mainly works by means of the mutual matching of the direct current conversion units, when one of the direct current conversion units fails, the whole micro-grid system can be unstable or even collapse. Therefore, when the micro-grid system is provided with more direct current conversion units, the failure probability of the micro-grid system can be multiplied, and the reliability of the micro-grid system is affected.
Disclosure of Invention
In order to solve the defects of the prior art, the invention aims to provide a mobile multi-energy micro-grid control method and system, which realize the advantages of combining renewable energy and a micro-grid system and realize the energy utilization of a mobile micro-grid.
The technical scheme adopted by the invention is as follows:
a mobile multi-energy micro-grid control method comprises the following steps:
s1, in a micro-grid starting stage, selecting a storage battery or a diesel engine generator set to be independently started as a main power supply for power supply according to the state of charge (SOC) of the storage battery, and starting a micro-grid system;
S2, entering a first stage after the micro-grid system is started, starting a fuel cell generator set to work, and according to the power P of the fuel cell fc Judging whether the output power of the fuel cell generator set is stable, and entering a second stage if the fuel cell generator set is stable; if the fuel cell generator set is unstable, the photovoltaic cell generator set, the storage battery, the diesel engine generator set and the diesel engine generator set are mutually combined to generate power so as to meet the load demand power P load 。
S3, a second stage: when the output power of the fuel cell generator set is stable, and the fuel cell generator set can work normally, the fuel cell generator set is used as a main power supply of the micro-grid system, and in the second stage, the photovoltaic cell generator set, the fuel cell generator set, the storage battery and the mutually combined power generation of the photovoltaic cell generator set and the storage battery meet the load demand power P load 。
Further, in the step S2, if the electric power storage is used as the main power supply and the photovoltaic cell generator set can normally work, the control process is as follows:
if P load ＜P pv_pre And SOC < SOC max The photovoltaic battery generator set is arranged at P according to the constant-voltage working mode pv_pre The point is to supply power to the output load end and charge the storage battery with redundant electric energy; if P load ＜P pv_pre And SOC > SOC max The photovoltaic cell generator set works in a power following mode and supplies power to an output load end; p (P) pv_pre For the power of the photovoltaic battery generator set, the SOC is the charge state of the storage battery, and the SOC max Respectively the upper limit value of the charge quantity of the storage battery;
if P load ＜P pv_max And SOC < SOC min The photovoltaic battery generator set is in MPPT mode to supply power for the output load end 3 and charges the storage battery with redundant power of the photovoltaic battery generator set; if P load ＜P pv_max And SOC (System on chip) min The SOC is not more than or equal to the SOC, and the photovoltaic cell generator set is in a power following mode; p (P) pv_max Is the maximum power of the photovoltaic generator set and SOC min Is the lower limit value of the charge quantity of the storage battery;
if P pv_max ＜P load The photovoltaic cell generator set and the storage battery jointly generate power, and the discharge power P of the storage battery ba ＝P load -P pv_max The method comprises the steps of carrying out a first treatment on the surface of the If P ba ＜P max Discharging the storage battery in a constant-voltage working mode; if P ba ＝P ba_max The storage battery works in the P/Q control mode, P ba_max Maximum power of the storage battery;
if P pv_max +P ba ＜P load Then the diesel generator set is combined for generating power, and the generating power of the diesel generator set is P diesel ＝P load -P ba_max -P pv_max ；
If P diesel +P ba_max +P pv_max ＜P load Judging whether a controllable load exists or not, if so, cutting off the controllable load and prompting that the load is overlarge; if the controllable load does not exist, the switch is disconnected to stop power supply, and the overload is prompted.
In the step S2, if the storage battery is used as the main power supply and the photovoltaic cell generator set cannot work normally, the control process is as follows:
If P load ＜P ba_max The storage battery is used for independently supplying power to the load end;
if P ba_max ＜P load Then the diesel engine generator set and the storage battery are started to generate power in a combined way, and the power of the diesel engine generator set is P diesel ＝P load -P ba_max ；
If P diesel +P ba_max ＜P load Judging whether a controllable load exists or not if the power of the storage battery combined diesel engine generator set cannot meet the power requirement of a load end, and if the controllable load exists, cutting off the controllable load by a control system to prompt that the load is overlarge; if the controllable load does not exist, the control system cuts off the switch, the power supply of the micro-grid system is stopped, and the overload is prompted.
If the diesel generator set is used as a main power supply and the photovoltaic battery generator set can work normally, the control process is as follows:
if P load ＜P pv_max The photovoltaic cell generator set can meet the end power requirement, the photovoltaic cell generator set is in an MPPT working mode to independently supply power for a load end, and redundant power of the photovoltaic cell generator set charges a storage battery;
if P pv_max ＜P load The photovoltaic cell generator set and the diesel engine generator set are combined to generate power, and the output power of the diesel engine generator set is P diesel ＝P load -P pv_max ；
If P diesel +P pv_max ＜P load Judging whether a controllable load exists or not, if so, cutting off the controllable load to prompt that the load is overlarge; if the controllable load does not exist, the load switch is cut off, power supply is stopped, and the overload is prompted.
In the step S2, if the diesel generator set is used as the main power supply and the photovoltaic cell generator set cannot normally work, the control process is as follows:
if P load ＜P diesel The diesel generator set can meet the end power requirement, and then the diesel generator set is used for independently supplying power;
if P diesel ＜P load Judging whether a controllable load exists or not, if so, cutting off the controllable load to prompt that the load is overlarge; if the controllable load does not exist, the load switch is cut off, power supply is stopped, and the overload is prompted.
Further, in the step S3, a switching rule between the power generating units in the second stage is as follows:
s3.1, when the photovoltaic cell generator set can work normally, and P pv_pre ＞P load The photovoltaic battery generator set is in a constant-voltage working mode to independently supply power to the load, the SOC of the storage battery is judged, and if the SOC is met min ＜SOC＜SOC max Or SOC (System on chip) min The photovoltaic cell generator set is in a constant-voltage working mode and charges the storage battery; if P load ＜P pv_max Judging that SOC is satisfied min ＜SOC＜SOC max Or SOC (System on chip) min The power of the storage battery is P, and the power of the storage battery is charged by the redundant power of the photovoltaic battery generator set charge ＝P pv_max -P load 。
S3.2, if P pv_max ＜P load If the fuel cell generator set and the photovoltaic cell generator set are required to generate power jointly, P is as follows fc +P pv_max ＞P load And SOC is less than or equal to SOC min The fuel cell generator set and the photovoltaic cell generator set are in MPPT mode to supply power for the load end, and the storage battery is charged until the SOC is more than or equal to the SOC max Stopping charging when the battery is charged; if SOC is min ＜SOC＜SOC max The fuel cell generator set and the photovoltaic cell generator set are used for combined power supply, the photovoltaic cell generator set (11) works in an MPPT mode to output maximum power, and the power P of the fuel cell generator set fc ＝P load -P pv_max If P fc ＜P fc_pre The fuel cell generator set is at P fc_pre Operating at a point, and charging the storage battery by redundant power; if P fc ＜P fc_max The fuel cell generator set is in a power following mode;
s3.3, if P fc_max +P pv_max ＜P load The fuel cell generator set, the photovoltaic cell generator set and the storage battery are required to generate power in a combined way; indicating that the combined power of the fuel cell generator set and the photovoltaic cell generator set does not meet the load demand power P load The SOC of the battery needs to be analyzed at this time, and the battery hasThe body is as follows:
when SOC is smaller than SOC min The storage battery can not normally supply power, and the fuel cell generator set and the photovoltaic cell generator set need to be combined with the diesel engine generator set; if P diesel +P fc_max +P pv_max ＞P load The output power of the fuel cell generator set, the photovoltaic cell generator set and the diesel engine generator set can meet the load power requirement, and the output power of the diesel engine generator set is P diesel ＝P load -P fcmax -P pv_max The method comprises the steps of carrying out a first treatment on the surface of the If P diesel +P fc_max +P pv_max ＜P load The method is characterized in that the output power of the fuel cell generator set, the photovoltaic cell generator set and the diesel engine generator set can not meet the load power requirement, the micro-grid central control system checks whether a controllable load exists at a load end, and if the controllable load exists, the controllable load is cut off and the load is prompted to be overlarge. If the controllable load does not exist, the load end control switch is cut off, power supply is stopped, and the overload is prompted;
if SOC > SOC is satisfied min If the storage battery can normally supply power, the fuel cell generator set, the photovoltaic cell generator set and the storage battery jointly supply power, and the output power of the storage battery is P ba ＝P load -P fc_max -P pv_max The method comprises the steps of carrying out a first treatment on the surface of the If P ba +P fc_max+ P pv_max ＜P load The fact that the combined power supply of the fuel cell generator set, the photovoltaic cell generator set and the storage battery is insufficient to meet the load power requirement is shown, the diesel generator set is needed to be combined, and the output power of the diesel generator set is P diesel ＝P load -P fc_max -P pv_max -P ba The method comprises the steps of carrying out a first treatment on the surface of the If P diesel +P fc_max +P pv_max +P ba ＜P load And (3) checking whether a controllable load exists at a load end or not if the output power of the fuel cell generator set, the photovoltaic cell generator set, the storage battery and the diesel engine generator set can not meet the load power requirement, and cutting off the controllable load and prompting that the load is overlarge if the controllable load exists. If no controllable load exists, the load end control switch is cut off, the power supply is stopped, And suggests that the load is excessive. The above operation mode is a control method for the whole micro-grid system in normal operation.
Further, the regulation method for suddenly reducing the load power of the micro-grid system comprises the following steps: current load power P load When P is compared with the output power of the power generation unit at the power generation side fc +P pv +P diesel ＞P load If SOC < SOC max The diesel generator 14 continues to work, the storage battery 5 stops working and enters a charging state, and the storage battery 5 is utilized to absorb the redundant power for charging; if SOC is greater than or equal to SOC max Indicating that the energy storage capacity of the storage battery 5 is insufficient to maintain the power balance or the energy storage device 13 is charged and saturated, the diesel generator set 14 enters a stop state, and the storage battery 5 works instead of the diesel generator set 14;
when P fc +P pv +P diesel ＜P load If SOC > SOC min The storage battery 5, the fuel cell generator set 12, the diesel generator set 14 and the photovoltaic cell generator set 11 supply power to the load together; if SOC is smaller than SOC min Judging whether a controllable load exists in the micro-grid system or not, if the controllable load exists in the micro-grid system, cutting off the controllable load, and prompting that the load is overlarge; if no controllable load exists in the system, the cut-off switch stops supplying power to prompt that the load is overlarge.
Further, the regulation and control method for suddenly increasing the load power of the micro-grid system comprises the following steps: when P fc +P pv +P diesel +P bat ＜P load Judging whether a controllable load exists in the micro-grid system or not, and if the controllable load exists at the load end, cutting off the controllable load by the control system to prompt that the load is overlarge; if the load end does not have the controllable load, the control system cuts off a switch of the load end, stops power supply and prompts that the load is overlarge.
Further, the regulation and control method for the occurrence of the abnormality of the power generation end of the micro-grid system comprises the following steps: the connection between the power generation unit with the fault and the power distribution system is disconnected in an emergency way, and the power generation unit is prompted to be faulty; at the same time judging the total power P of other power generation units total If P is the condition that whether the whole micro-grid system can be supported to work normally total ＞P load The remaining power generation units can be supported and only the connection between the power generation unit and the power distribution system is broken; if P total ＜P load Judging whether a controllable load exists at the output load end, if so, disconnecting the controllable load and prompting that the load is overlarge; if the controllable load does not exist, the switch of the load end 3 is disconnected to stop power supply, and the overload is prompted.
Further, the regulation and control method for the black start of the micro-grid system comprises the following steps: detecting the current SOC of the storage battery 5, if SOC is more than SOC min The diesel generator set 14 and the storage battery 5 are combined to supply power, and the limited electric energy only supports important loads and drives other power generation units to generate power; if SOC is smaller than SOC min The diesel generator set 14 works alone to output power, and the storage battery pauses charging and discharging; after the black start, the diesel generator set 14 and the storage battery 5 or the diesel generator set 14 drive the fuel cell 12 and the photovoltaic generator set 11 to start, and the starting stage is restarted to return to the normal working process, and the working modes of the first stage and the second stage are returned.
A movable multi-energy micro-grid system comprises a direct current side DG unit 1, a power distribution system 2, an output load end 3 and a micro-grid central control system 4; the direct current side DG unit 1 comprises a photovoltaic cell generator set 11, a fuel cell generator set 12, an energy storage device 13 and a diesel generator set 14; the low-voltage DC bus is respectively connected with a first DC-DC converter 15, a second DC-DC converter 16, a bidirectional circulating DC-DC converter 17 and an AC-DC converter 18 of the DC side DG unit 1, and is connected with the medium-voltage DC bus through a booster 21, and the medium-voltage DC bus is connected with the output load end 3; the output load end 3 comprises an alternating current load and a direct current load; the micro-grid central control system 4 is respectively connected with each component in the direct current side DG unit 1, the power distribution system 2 and the output load end 3 through a CAN bus; and controls the switching of the operations of the dc side DG unit 1, the power distribution system 2, and the output load terminal 3.
The invention has the beneficial effects that:
the invention takes the fuel cell as a main power supply, the fuel cell has the characteristics of high efficiency, small pollution and strong adaptability, and the fuel cell is used as a fixed power generation unit to amplify the working advantages of the fuel cell, so that the power generation of the fuel cell is efficient and stable through a control system; according to the hierarchical control system, real-time data of the micro-grid system are collected and processed, and the micro-grid system is scheduled through a mathematical model, so that the micro-grid system has flexible expansibility and contractibility; the invention establishes the storage battery energy management system, accurately manages the storage battery capacity through storage battery information acquisition, completes intelligent control of the energy storage system, and ensures that the spring mud is more stable and reliable in operation.
Drawings
FIG. 1 is a schematic diagram of a mobile multi-energy microgrid system of the present invention;
fig. 2 is a block diagram of the bidirectional flow-through converter 17;
FIG. 3 is a startup control flow diagram of the mobile multi-energy microgrid system of the present invention;
FIG. 4 is a control flow diagram of the stage in which the 1 st order internal battery is the main power supply;
FIG. 5 is a control flow diagram of the stage of the 1 st order internal diesel generator as the primary power source;
Fig. 6 is a control flow chart of the fuel cell at stage 2 as the main power source;
FIG. 7 is a flow chart of a system upon failure within a microgrid system;
FIG. 8 is a flow chart of a micro-grid system power down in a black start state;
in the figure, 1, a direct current side DG unit, 2, a distribution system, 3, an output load end, 4, a microgrid central control system, 5, a storage battery, 6, a super capacitor, 11, a photovoltaic cell generator set, 12, a fuel cell generator set, 13, an energy storage device, 14, a diesel generator set, 15, a first DC-DC converter, 16, a second DC-DC converter, 17, a bidirectional flow DC-DC converter, 18, an AC-DC converter, 21, a booster, 22, a DC-AC converter, 23, a third DC-DC converter, 24, an AC-AC converter, 31, a first AC load, 32, a second AC load, 33, a first DC load, 34 and a second DC load.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
The invention relates to a mobile multi-energy micro-grid system, which is shown in fig. 1, and specifically comprises a direct current side DG unit 1, a power distribution system 2, an output load end 3 and a micro-grid central control system 4. The direct current side DG unit 1 comprises a photovoltaic cell generator set 11, a fuel cell generator set 12, an energy storage device 13 and a diesel engine generator set 14; the output end of the photovoltaic cell generator set 11 is connected with the first DC-DC converter 15 through a wire, the output end of the fuel cell generator set 12 is connected with the second DC-DC converter 16 through a wire, the output end of the energy storage device 13 is connected with the bidirectional circulating DC-DC converter 17 through a wire, the output end of the diesel generator set 14 is connected with the AC-DC converter 18 through a wire, and the first DC-DC converter 15, the second DC-DC converter 16, the bidirectional circulating DC-DC converter 17 and the AC-DC converter 18 are all connected with the power distribution system 2.
The power distribution system 2 comprises a low-voltage direct-current bus, a medium-voltage direct-current bus and an alternating-current bus, wherein the low-voltage direct-current bus is respectively connected with a first DC-DC converter 15, a second DC-DC converter 16, a bidirectional circulating DC-DC converter 17 and an AC-DC converter 18 of the direct-current side DG unit 1, the low-voltage direct-current bus is connected with the medium-voltage direct-current bus through a booster 21, and the medium-voltage direct-current bus is connected with the output load end 3.
The output load end 3 comprises an alternating current load and a direct current load, the alternating current load comprises a first alternating current load 31 and a second alternating current load 32, more specifically, a DC-AC converter 22, an alternating current bus and an AC-AC converter 24 are sequentially connected in series between the medium voltage direct current bus and the first alternating current load 31; a DC-AC converter 22 and an AC bus are connected in series between the medium voltage DC bus and the second AC load 32. The direct current load comprises a first direct current load 33 and a second direct current load 34, and a third DC-DC converter 23 is sequentially connected in series between the medium voltage direct current bus and the first direct current load 33; the medium voltage dc bus is directly connected to the first dc load 33. And circuit switches, denoted by K1, K2, K3 and K4, are provided for the connection of the respective loads. Through the four circuits, four voltage requirements of 48/220V direct-current voltage and 220/380V alternating-current voltage at the output end are met.
The micro-grid central control system 4 is respectively connected with each component in the direct current side DG unit 1, the power distribution system 2 and the output load end 3 through a CAN bus; the microgrid central control system 4 is used for collecting information such as load power demand of an output end, voltage on a current bus, SOC of a storage battery, power generated by a photovoltaic generator set, power generated by a fuel cell and the like, and controlling work switching of the direct current side DG unit 1, the power distribution system 2 and the output load end 3.
The energy storage device 13 comprises a storage battery 5 and a super capacitor 6, and the storage battery 5 and the super capacitor 6 are in a complementary working mode through a bidirectional circulating DC-DC converter 17; the bidirectional circulating DC-DC converter 17 adopts a Buck-Boost converter, as shown in fig. 2, both the storage battery 5 and the super capacitor 6 are provided with the same bidirectional converter, and both the storage battery 5 and the super capacitor 6 are connected with a low-voltage DC bus through the bidirectional converter.
In the working process, a low-voltage direct-current bus voltage threshold is set firstly, when the low-voltage direct-current bus voltage exceeds the threshold (the rated voltage of the direct-current bus is 10%), the bidirectional circulating DC-DC converter 17 works in a Buck mode, the super capacitor 6 absorbs redundant electric energy from the low-voltage direct-current bus to charge, the super capacitor 6 has good transient response, if the low-voltage direct-current bus is only excessively high in short time, only the super capacitor is used, and if the voltage on the low-voltage bus still exceeds the threshold after the super capacitor is full, the storage battery 5 absorbs electric energy from the low-voltage bus; when the voltage of the direct current bus is lower than a threshold value (10% of the rated voltage of the direct current bus), the bidirectional circulating DC-DC converter 17 works in a Boost mode, the energy storage device transmits the electric energy stored by the super capacitor 6 to the low-voltage direct current bus, and the storage battery 5 transmits the electric energy to the low-voltage bus after the electric energy of the super capacitor 6 is discharged; the bidirectional circulating DC-DC converter 17 is controlled by a pulse width modulation PWM technology, so that two semiconductor devices work, drive signals are sent out in different time periods, and the bidirectional converter formed by the bidirectional converter of the super capacitor 6 and the storage battery 5 work at different moments, so that the super capacitor 6 and the storage battery 5 can perform complementary working modes.
The battery 5 has a constant power control mode (P/Q control mode) and a constant voltage (V/F) control mode. When constant power control is adopted, the active power and reactive power references of the bidirectional circulating DC-DC converter 17 can be set according to the external power demand, so that the supply and demand balance is achieved. The constant power control mode can be divided into two links: an outer loop power control link and an inner loop current control link. When the outer loop of the P/Q control mode is controlled, comparing the reference value of the output or input power of the set converter with the actual value, and enabling the error after comparison to enter a PI controller to obtain a current reference value controlled by the inner loop; the current inner loop control is used for controlling the actual current and the control current signals, and the result is regulated by the PI controller to ensure the stable output power. When the storage battery works in the constant voltage mode, the constant voltage control mode can be divided into two links: in the voltage outer ring, comparing the set reference frequency and reference voltage with the acquired bus frequency and bus voltage, and respectively obtaining a current reference value controlled by the output inner ring by a PI controller according to the difference value of the two; the inner ring collects the difference value between the current signal and the reference current, and outputs a modulation signal through PI adjustment, so that the stability of the output voltage is ensured.
Because the excessive charge and discharge power of the storage battery 5 can cause damage to the storage battery 5, the service life of the storage battery 5 is reduced, and meanwhile, the aging of the storage battery 5 can be accelerated due to the over-deep discharge or the over-charge, therefore, the charge and discharge power of the storage battery 5 needs to be controlled as necessary, and a specific constraint algorithm is as follows:
P charge ≤P charge_max
P discharge ≤P discharge_max
SOC min ≤SOC≤SOC max
wherein: p (P) charge And P discharge The charging power and the discharging power of the storage battery are respectively; p (P) charge_max And P discharge_max Maximum charge allowable power and maximum discharge allowable power of the storage battery respectively; SOC is the charge quantity of the storage battery; SOC (State of Charge) min And SOC (System on chip) max Respectively the charge quantity of the storage batteryLower limit and upper limit of (a).
The photovoltaic power generation unit 11 has fluctuation and intermittence because the photovoltaic power generation amount is limited by weather factors, so that the photovoltaic power generation can only be used as a driven power generation unit, and the constraint algorithm is designed according to the normal working conditions:
P PV_min ≤P pv ≤P PV_max
-P PV ≤ΔP PV ≤P PV_re -P PV
wherein: p (P) pv The operating power of the photovoltaic generator set; p (P) PV_min The minimum starting power of the photovoltaic generator set is set; p (P) PV_max The rated power of the photovoltaic generator set is set; ΔP PV The power value is regulated for the photovoltaic generator set; p (P) PV_re And the power generation capacity is predicted for the ultra-short period under the photovoltaic cell.
The diesel generator set 14, when the running power of the diesel generator set 14 is smaller, the fuel cannot be completely combusted, the generating efficiency of the diesel generator set 14 is lower, and the fuel consumption is larger at the moment, so that the diesel generator can be operated efficiently and economically, and the minimum generating power constraint of the diesel generator needs to be set:
P diesel_min ≤P diesel ≤P diesel_max
Wherein: p (P) diesel For the operating power of the diesel generator set, P diesel_min For minimum starting power of diesel engine set, P diesel_max And the maximum power value is output by the diesel engine generator set.
A mobile multi-energy micro-grid control method comprises the following steps:
s1, starting: when the whole micro-grid is started to work, the fuel cell needs time to react to reach a stable power generation state, the photovoltaic power generation also needs reaction time, and the photovoltaic power generation capacity is not stable; therefore, the micro-grid is started by using a stable and reliable power supply as a main power supply, the micro-grid is independently started by the storage battery 5 or the diesel engine generator set 14 in the starting stage to supply power to the whole micro-grid, and the decision in the starting stage is made by taking the storage battery 5 or the diesel engine generator set 14 as the main power supply to carry out the judgment basis: after receiving the micro-grid starting signal, collecting the state of charge (SOC) of the storage battery 5; judging the state of the SOC of the battery 5 as shown in fig. 3;
if SOC is smaller than SOC min The diesel generator set 14 is used as a main power supply to start the micro-grid system;
if SOC is min The SOC is less than or equal to the SOC, the storage battery 5 is used as a main power supply to start the micro-grid system;
wherein SOC is min And SOC (System on chip) max The main power supply at the starting stage is selected according to the state of charge (SOC) of the storage battery.
S2, a first stage: when the storage battery or the diesel generator set 14 is used as a main power supply source, the micro-grid system is started; during this phase, the fuel cell power generator set 12 starts to operate, performs a warm-up operation, and is operated according to the fuel cell power P fc Judging whether the fuel cell generator set 12 is stable (namely, whether the output power is stable near a set value), and entering a second stage if the fuel cell generator set 12 is stable; if the fuel cell generator set 12 is unstable, it is determined whether the photovoltaic cell generator set 11, the storage battery 5, the diesel engine generator set 14 and the combined power generation energy of each other meet the load power requirement.
S2.1, when the storage battery 5 is used as a main power supply, as shown in FIG. 4, judging whether the photovoltaic cell generator set 11 can work normally according to whether the photovoltaic cell generator set 11 can generate electric energy; according to the load demand power P load Power P with photovoltaic cell generator set pv_pre Is controlled by the relation of (a).
Case 1, if the photovoltaic cell generator set 11 can work normally and satisfies P load ＜P pv_pre Load demand power P load Less than the power P of the photovoltaic battery generator set pv_pre The control system 4 judges the state of charge (SOC) of the storage battery; if SOC is smaller than SOC max When the photovoltaic battery generator set 11 works in the constant voltage operation mode, the photovoltaic battery generator set works in the constant voltage operation mode pv_pre The point is to supply power to the output load end 3, and the photovoltaic cell generator set 11 supplies surplus power to the storage battery 5Charging; if SOC > SOC max When the photovoltaic battery generator set 11 works in the power following mode, the load demand power P is met load And (3) obtaining the product.
Case 2, if P is satisfied load ＜P pv_max Load demand power P load Less than the maximum power P of the photovoltaic generator set pv_max The method comprises the steps of carrying out a first treatment on the surface of the At the same time, the SOC of the storage battery 5 is judged, if the SOC is less than the SOC max When the photovoltaic power generation unit 11 is in MPPT mode (i.e. maximum power mode) to supply power to the output load end 3, and the redundant power of the photovoltaic power generation unit 11 charges the storage battery 5, the charging power of the storage battery 5 is P charge ＝P pv_max -P load . If SOC is max And less than or equal to SOC, the photovoltaic cell generator set 11 is in a power following mode.
Case 3, if P is satisfied pv_max ＜P load When the maximum power P of the photovoltaic generator set 11 pv_max If P when the required power of the load is not satisfied pv_max +P ba ＞P load The description that the power required by the load can be met only by the combined power generated by the photovoltaic battery generator set 11 and the storage battery 5, and the discharging power of the storage battery 5 is P ba ＝P load -P pv_max If P ba ＜P ba_max The battery 5 is discharged in the constant-voltage operation mode; if P ba ＝P ba_max The battery 5 is operated in the P/Q control mode, P ba_max Is the maximum generated power of the battery 5.
Case 4, if P pv_max +P ba_max ＜P load Indicating that the combined power generated by the storage battery 5 and the photovoltaic battery generator set 11 can not meet the load demand power P load Then the diesel generator set 14 needs to be combined to generate power, and the power generated by the diesel generator set 14 is P diesel ＝P load -P ba_max -P pv_max ；
In case 5, if it is stated that the combined power generated by the storage battery 5, the photovoltaic cell generator set 11 and the diesel generator set 14 cannot meet the load demand power P load The micro-grid central control system 4 judges whether or not there is a spaceIf the controllable load exists, the control system 4 cuts off the controllable load and prompts that the load is overlarge; if the controllable load does not exist, the switch is disconnected to stop power supply, and the overload is prompted.
S2.2, when the storage battery 5 is used as a main power supply and the photovoltaic battery generator set 11 cannot work normally, the power P is required according to the load load Power P to battery ba Is controlled by the relation of the control program.
Case 1, if P is satisfied load ＜P ba_max When the power of the storage battery 5 can meet the load power requirement, the storage battery 5 independently supplies power to a load end;
case 2, if P ba_max ＜P load If the output power of the storage battery 5 can not meet the load power requirement, the diesel generator set 14 is started to generate power in a combined mode, and the power of the diesel generator set 14 is P diesel ＝P load -P ba_max ；
Case 3, if P diesel +P ba_max ＜P load When the power of the storage battery 5 combined with the diesel engine generator set 14 cannot meet the power requirement of the load end, the micro-grid central control system 4 judges whether a controllable load exists, and if the controllable load exists, the control system cuts off the controllable load to prompt that the load is overlarge; if the controllable load does not exist, the control system cuts off the switch, the power supply of the micro-grid system is stopped, and the overload is prompted.
S2.3, as shown in FIG. 5, when the diesel generator set 14 is used as a main power supply, judging whether the photovoltaic cell generator set 11 can work normally according to whether the photovoltaic cell generator set 11 can generate electric energy; according to the load demand power P load Power P with photovoltaic cell generator set pv_pre Is controlled by the relation of (a).
Case 1, if the photovoltaic cell generator set 11 is able to operate normally and if P is satisfied pv_max ＞P load And the micro-grid central control system 4 controls the photovoltaic cell generator set 11 to be in an MPPT working mode, namely, charges the storage battery 5 with redundant power of the photovoltaic cell generator set 11 according to the maximum power output.
Case 2, ifP pv_max ＜P load Description of maximum Power P of photovoltaic cell Generator set 11 pv_max Not enough to support the entire micro-grid system to operate; the photovoltaic cell generator set 11 is required to work in combination with the diesel engine generator set 14, and the output power of the diesel engine generator set 14 is P diesel ＝P load -P pv_max 。
Case 3, if P diesel +P pv_max ＜P load The power generated by the combined generation of the photovoltaic battery generator set 11 and the diesel engine generator set 14 is smaller than the load demand power P load The micro-grid central control system 4 checks whether a controllable load exists at a load end, and if the controllable load exists, the controllable load is cut off to prompt that the load is overlarge; if the controllable load does not exist, the load switch is cut off, power supply is stopped, and the overload is prompted.
S2.4, when the diesel generator set 14 is used as a main power supply and the photovoltaic battery generator set 11 cannot work normally, the power P is required according to the load load Power P generated by the diesel generator set 14 diesel Is controlled by the relation of (a).
Case 1, if P is satisfied diesel ＞P load The diesel generator set 14 is independently powered;
case 2, if P load ＞P diesel The micro-grid central control system 4 checks whether a controllable load exists at a load end, and if the controllable load exists, the controllable load is cut off to prompt that the load is overlarge; if the controllable load does not exist, the load switch is cut off, power supply is stopped, and the overload is prompted.
S3, a second stage: the output power of the fuel cell generator set 12 is stable, and when the fuel cell generator set 12 can work normally, the fuel cell generator set 12 is used as a main power supply of the micro-grid system as shown in fig. 6; the switching rule between each power generation unit in the second stage is as follows:
S3.1, when the photovoltaic cell generator set 11 can normally generate electricity and work, the microgrid center control system 4 judges the output power P of the photovoltaic cell generator set 11 pv_pre Whether or not the load demand power P can be satisfied load If P is satisfied pv_pre ＞P load The load is powered solely by the photovoltaic cell generator set 11 and the photovoltaic cell generator set 11 is in a constant voltage mode of operation. If the load requires power P load ＜P pv_max The method comprises the steps of carrying out a first treatment on the surface of the The SOC of the battery 5 is determined, and if the SOC is smaller than the SOC max The photovoltaic cell generator set 11 is in a constant voltage operation mode and charges the storage battery 5; if SOC < SOC is satisfied min The photovoltaic cell generator set 11 is in MPPT mode (i.e. maximum power mode), and the redundant power of the photovoltaic cell generator set 11 charges the storage battery with the charging power of P charge ＝P pv_max -P load 。
S3.2, if the maximum power P of the photovoltaic battery generator set 11 pv_max ＜P load When the photovoltaic cell generator set 11 is insufficient to supply power to the whole micro-grid system, the micro-grid central control system 4 controls the fuel cell generator set 12 and the photovoltaic cell generator set 11 to jointly generate power. If P fc +P pv_max ＞P load The combined power generation power of the fuel cell power generator set 12 and the photovoltaic cell power generator set 11 is described as satisfying the load demand power P load Further judging the state of the SOC of the storage battery, if the SOC is less than or equal to the SOC min The fuel cell generator set 12 and the photovoltaic cell generator set 11 are in MPPT mode, and supply more residual power to the storage battery 5 until the SOC of the storage battery 5 is more than or equal to the SOC max Stopping charging when the battery is charged; if SOC > SOC min The fuel cell generator set 12 and the photovoltaic cell generator set 11 jointly supply power, the photovoltaic cell generator set 11 works in the MPPT mode to output the maximum power, and the power P of the fuel cell generator set 12 fc ＝P load -P pv_max If P fc ＜P fc_pre The fuel cell generator set 12 is at P fc_pre The point work is carried out, and the redundant power charges the storage battery 5; if P fc ＜P fc_max The fuel cell power generator set 12 is in the power following mode.
S3.3, when P fc_max +P pv_max ＜P load It is explained that the combined power generated by the fuel cell generator set 12 and the photovoltaic cell generator set 11 does not meet the load demand power P load The SOC condition of the battery 5 at this time needs to be analyzed to determine whether the battery 5 can generate power in combination with the fuel cell generator set 12 and the photovoltaic cell generator set 11 to satisfy the load demand power P load . The specific process is as follows:
when SOC is smaller than SOC min The fact that the storage battery 5 cannot normally supply power at the moment is indicated, and the fuel cell generator set 12 and the photovoltaic cell generator set 11 need to be combined with the diesel engine generator set 14; if P diesel +P fc_max +P pv_max ＞P load The output power of the fuel cell generator set 12, the photovoltaic cell generator set 11 and the diesel engine generator set 14 can meet the load power requirement, and the output power of the diesel engine generator set 14 is P at the moment diesel ＝P load -P fc_max -P pv_max The method comprises the steps of carrying out a first treatment on the surface of the If P diesel +P fc_max +P pv_max ＜P load Indicating that the output power of the fuel cell generator set 12, the photovoltaic cell generator set 11 and the diesel engine generator set 14 cannot meet the load power requirement, the micro-grid central control system 4 checks whether a controllable load exists at the load end, and if the controllable load exists, the controllable load is cut off and the overload is prompted. If the controllable load does not exist, the load end control switch is cut off, power supply is stopped, and the overload is prompted. The above operation mode is a control method for the whole micro-grid system in normal operation.
If SOC > SOC is satisfied min When the storage battery 5 can normally supply power, the fuel cell generator set 12, the photovoltaic cell generator set 11 and the storage battery 5 jointly supply power, and the output power of the storage battery 5 is P ba ＝P load -P fc_max -P pv_max The method comprises the steps of carrying out a first treatment on the surface of the If P ba_max +P fc_max +P pv_max ＜P load It is explained that the combined power supply of the fuel cell generator set 12, the photovoltaic cell generator set 11 and the storage battery 5 is insufficient to meet the load power requirement, and the diesel generator set 14 is needed to be combined, and the output power of the diesel generator set 12 is P diesel ＝P load -P fc_max -P pv_max -P ba_max The method comprises the steps of carrying out a first treatment on the surface of the If P diesel +P fc_max +P pv_max +P ba_max ＜P load Indicating that the output power of the fuel cell generator set 12, the photovoltaic cell generator set 11, the storage battery 5 and the diesel engine generator set 14 cannot meet the load power demand, the microgrid central control system 4 checks whether a controllable load exists at the load end, and if the controllable load exists, the controllable load is cut off and the overload is prompted. If the controllable load does not exist, the load end control switch is cut off, power supply is stopped, and the overload is prompted. The above operation mode is a control method for the whole micro-grid system in normal operation.
Aiming at possible faults of the whole micro-grid system during operation, such as sudden load fluctuation (sudden load increase or sudden load decrease) at a load end and sudden operation faults of a power generation unit (DG unit), the method also provides a series of regulation and control methods, and the specific processes are as follows:
as shown in fig. 7, when the load at the load end fluctuates, the power demand is unstable, and the microgrid central control system 4 starts a checking program to determine whether the load fluctuation is small or large.
If the load power suddenly decreases, the micro-grid central control system 4 will send the current load power P load If P is satisfied as compared with the output power of the power generation unit on the power generation side fc +P pv +P diesel ＞P load Description of load demand Power P load When the power is smaller than the sum of the power generation powers of the fuel cell generator set 12, the photovoltaic cell generator set 11 and the diesel engine generator set 14, the microgrid central control system 4 judges whether the SOC value of the storage battery is smaller than the SOC max If SOC is less than SOC max The diesel generator 14 continues to work, the storage battery 5 stops working and enters a charging state, and the storage battery 5 is utilized to absorb the redundant power for charging; if SOC is greater than or equal to SOC max Indicating that the energy storage capacity of the battery 5 is insufficient to maintain the power balance or that the energy storage device 13 has been charged to saturation, the diesel-electric set 14 is put into a stopped state, and the battery 5 operates instead of the diesel-electric set 14.
When P fc +P pv +P diesel ＜P load If SOC > SOC min The accumulator (5) and the fuel cell generator set are used for the power generation12 A diesel generator set (14) and a photovoltaic cell generator set (11) together supply power to a load; if SOC is smaller than SOC min Judging whether a controllable load exists in the micro-grid system or not, if the controllable load exists in the micro-grid system, cutting off the controllable load, and prompting that the load is overlarge; if no controllable load exists in the system, the cut-off switch stops supplying power to prompt that the load is overlarge.
If the load end is suddenly connected to high-power load equipment, the load power is suddenly increased; the micro-grid central control system 4 is based on P fc +P pv +P diesel +P bat ＜P load Judging the load demand power P load Whether or not the power is greater than the sum of the power generated by the fuel cell generator set 12, the photovoltaic cell generator set 11, the diesel generator set 14 and the storage battery 5, if the load requires the power P load Greater than P fc +P pv +P diesel +P bat The micro-grid central control system 4 judges whether a controllable load exists in the micro-grid system, if the controllable load exists at the load end, the control system cuts off the controllable load and prompts that the load is overlarge; if the load end does not have the controllable load, the control system cuts off a switch of the load end, stops power supply and prompts that the load is overlarge.
When the direct current side DG unit 1 is abnormal, that is, the power generation unit suddenly withdraws from the working state, the microgrid central control system 4 emergently disconnects the problematic power generation unit in the direct current side DG unit 1 from the power distribution system 2, and prompts the power generation unit to fail. Next, the microgrid central control system 4 determines the total power P of the other power generation units of the dc side DG unit 1 total If P is the condition that whether the whole micro-grid system can be supported to work normally total ＞P load The remaining power generation units can be supported and only the connection between the power generation unit and the power distribution system is broken; if P total ＜P load It is determined whether the controllable load exists at the output load terminal 3. If the controllable load exists, the micro-grid central control system 4 disconnects the controllable load and prompts that the load is overlarge; if no controllable load exists, the micro-grid central control system 4 turns off the switch of the load end 3 to stop power supply, and prompts that the load is overlarge.
When the micro-grid central control system 4 detects that the micro-grid system is in the stateIn the black start state, the micro-grid central control system 4 detects the current SOC value of the storage battery, if SOC is larger than SOC min The diesel generator set 14 and the storage battery 5 are combined to supply power, but the electric energy is limited and only supports important loads (mainly meets the power requirement of 220V or more) and drives other power generation units to generate power; if SOC is smaller than SOC min The diesel generator set 14 operates alone to output power and the battery is suspended from charging and discharging.
After the black start, the diesel generator set 14 and the storage battery 5 or the diesel generator set 14 drive the fuel cell 12 and the photovoltaic generator set 11 to start, and the starting stage is restarted to return to the normal working process, and the working modes of the first stage and the second stage are returned.
According to the invention, by designing the control process aiming at black start, when the micro-grid system is suddenly electrified due to faults, the response of the control layer is triggered S4, the whole micro-grid system is taken over to drive the unstable power generation unit to generate power by using the start with self-starting capability in the system, the power generation capability is enlarged, and the working capability of the micro-grid system is gradually restored.
The above embodiments are merely for illustrating the design concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement the same, the scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications according to the principles and design ideas of the present invention are within the scope of the present invention.

Claims (6)

1. The mobile multi-energy micro-grid control method is characterized by comprising the following steps of:
s1, in a micro-grid system starting stage, according to the state of charge (SOC) of a storage battery (5), the storage battery (5) or a diesel engine generator set (14) is independently started to serve as a main power supply to supply power, and the micro-grid system is started;
s2, entering a first stage after the micro-grid system is started, starting a fuel cell generator set (12) to work, and according to the power P of the fuel cell fc Judging whether the output power of the fuel cell generator set (12) is stable or not, if the output power of the fuel cell generator set (12)) The second stage is entered when the stability is stabilized; if the fuel cell generator set (12) is unstable, the photovoltaic cell generator set (11), the storage battery (5), the diesel engine generator set (14) and the combination thereof generate electricity to meet the load demand power P load ；
S3, a second stage: when the output power of the fuel cell generator set (12) is stable, and the fuel cell generator set (12) can work normally, the fuel cell generator set (12) is used as a main power supply of the micro-grid system, and in the second stage, the photovoltaic cell generator set (11), the fuel cell generator set (12), the storage battery (5), the diesel engine generator set (14) and the mutual combination thereof generate power to meet the load demand power P load ；
In the step S2, if the storage battery (5) is used as a main power supply and the photovoltaic cell generator set (11) can normally work, the control process is as follows:
if P load <P pv_pre And SOC (System on chip)<SOC max The photovoltaic battery generator set (11) is arranged at P according to the constant-voltage working mode pv_pre The point is to supply power to the output load end (3) and charge the storage battery (5) with redundant electric energy; if P load <P pv_pre And SOC (System on chip)>SOC max The photovoltaic cell generator set (11) works in a power following mode and supplies power for the output load end (3); p (P) pv_pre For the power of the photovoltaic battery generator set, the SOC is the charge state of the storage battery (5), and the SOC max Is the upper limit value of the charge quantity of the storage battery;
if P load <P pv_max And SOC (System on chip)<SOC max The photovoltaic battery generator set (11) is in an MPPT mode to supply power for the output load end (3) and redundant power of the photovoltaic battery generator set (11) is used for charging the storage battery (5); if P load <P pv_max And SOC (System on chip) max The SOC is less than or equal to the SOC, and the photovoltaic cell generator set (11) is in a power following mode; p (P) pv_max Is the maximum power of the photovoltaic battery generator set (11), SOC max Is the upper limit value of the charge quantity of the storage battery;
if P pv_max <P load The photovoltaic battery generator set (11) and the storage battery (5) jointly generate power, and the discharge power P of the storage battery (5) ba ＝P load -P pv_max The method comprises the steps of carrying out a first treatment on the surface of the If P ba <P ba_max The accumulator (5) is discharged in a constant voltage operating mode; if P ba ＝P ba_max The storage battery works in the P/Q control mode, P ba_max Maximum power of the storage battery;
if P pv_max +P ba_max <P load Then the diesel generator set (14) is combined for generating power, and the power generation of the diesel generator set (14) is P diesel ＝P load -P ba_max -P pv_max ；
If P diesel +P ba_max +P pv_max <P load Judging whether a controllable load exists or not, if so, cutting off the controllable load and prompting that the load is overlarge; if the controllable load does not exist, the switch is disconnected to stop power supply, and the overload is prompted;
in the step S2, if the storage battery (5) is used as the main power supply and the photovoltaic cell generator set (11) cannot work normally, the control process is as follows:
If P load <P ba_max The storage battery (5) is used for independently supplying power to the load end;
if P ba_max <P load Then the diesel engine generator set (14) and the storage battery (5) are started to generate power in a combined way, and the power of the diesel engine generator set (14) is P diesel ＝P load -P ba_max ；
If P diesel +P ba_max <P load Judging whether a controllable load exists or not if the power of the storage battery (5) combined with the diesel engine generator set (14) cannot meet the power requirement of a load end, and if the controllable load exists, cutting off the controllable load by a control system to prompt that the load is overlarge; if the controllable load does not exist, the control system cuts off the switch, stops the power supply of the micro-grid system, and prompts that the load is overlarge;
if the diesel generator set (14) is used as a main power supply and the photovoltaic battery generator set (11) can work normally, the control process is as follows:
if P load <P pv_max The photovoltaic cell generator set (11) can meet the power requirement of the load end, and then the photovoltaic cellThe power generator set (11) is in an MPPT working mode to independently supply power to a load end, and redundant power of the photovoltaic battery power generator set (11) is used for charging the storage battery (5);
if P pv_max <P load The photovoltaic cell generator set (11) and the diesel engine generator set (14) jointly generate power, and the output power of the diesel engine generator set (14) is P diesel ＝P load -P pv_max ；
If P diesel +P pv_max <P load Judging whether a controllable load exists or not, if so, cutting off the controllable load to prompt that the load is overlarge; if the controllable load does not exist, the load switch is cut off, power supply is stopped, and the overload is prompted;
In the step S2, if the diesel generator set (14) is used as a main power supply and the photovoltaic cell generator set (11) cannot normally work, the control process is as follows:
if P load <P diesel The diesel generator set (14) can meet the power requirement of a load end, and the diesel generator set (14) is used for independently supplying power;
if P diesel <P load Judging whether a controllable load exists or not, if so, cutting off the controllable load to prompt that the load is overlarge; if the controllable load does not exist, the load switch is cut off, power supply is stopped, and the overload is prompted;
in the step S3, the switching rule between the power generating units in the second stage is as follows:
s3.1, when the photovoltaic battery generator set (11) can work normally, and P pv_pre >P load The photovoltaic battery generator set (11) is in a constant-voltage working mode to independently supply power to the load, the SOC of the storage battery (5) is judged, and if the SOC is met min <SOC<SOC max Or SOC (System on chip) min The power generation unit (11) is in a constant-voltage working mode and charges the storage battery (5); if P load <P pv_max Judging that SOC is satisfied min <SOC<SOC max Or SOC (System on chip) min More than or equal to SOC, the photovoltaic battery generator set (11) is in MPPT mode, and redundant power of the photovoltaic battery generator set (11) is supplied to the storage batteryCharging power of the storage battery is P c h arge ＝P pv_max -P load ；
S3.2, if P pv_max <P load A fuel cell generator set (12) and a photovoltaic cell generator set (11) are required to generate power in a combined mode; if P fc +P pv_max >P load And SOC is less than or equal to SOC min The fuel cell generator set (12) and the photovoltaic cell generator set (11) are in MPPT mode to supply power for a load end, and the storage battery (5) is charged until the SOC is more than or equal to the SOC max Stopping charging if SOC min <SOC<SOC max The fuel cell generator set (12) and the photovoltaic cell generator set (11) jointly supply power, the photovoltaic cell generator set (11) outputs maximum power when working in an MPPT mode, and the power P of the fuel cell generator set (12) fc ＝P load -P pv_max If P fc <P fc_pre The fuel cell generator set (12) outputs power P fc_pre The point work is carried out, and the redundant power charges a storage battery (5); if P fc <P fc_max The fuel cell power generator set (12) is in a power following mode;
s3.3, if P fc_max +P pv_max <P load The fuel cell generator set (12), the photovoltaic cell generator set (11) and the storage battery (5) are required to generate power in a combined mode; indicating that the combined power of the fuel cell generator set (12) and the photovoltaic cell generator set (11) does not meet the load demand power P load The SOC state of the battery (5) at this time needs to be analyzed, specifically as follows:
when SOC is less than or equal to SOC min The storage battery (5) cannot normally supply power, and the fuel cell generator set (12) and the photovoltaic cell generator set (11) need to be combined with the diesel engine generator set (14); if P diesel +P fc_max +P pv_max >P load The output power of the fuel cell generator set (12), the photovoltaic cell generator set (11) and the diesel engine generator set (14) can meet the load power requirement, and the output power of the diesel engine generator set (14) is P diesel ＝P load -P fc_max -P pv_max The method comprises the steps of carrying out a first treatment on the surface of the If P diesel +P fc_max +P pv_max <P load The method comprises the steps that the output power of a fuel cell generator set (12), a photovoltaic cell generator set (11) and a diesel engine generator set (14) can not meet the load power requirement, a microgrid central control system (4) checks whether a controllable load exists at a load end, and if the controllable load exists, the controllable load is cut off and the overload is prompted; if the controllable load does not exist, the load end control switch is cut off, power supply is stopped, and the overload is prompted;
if SOC is satisfied>SOC min The storage battery (5) can normally supply power, then the fuel cell generator set (12), the photovoltaic cell generator set (11) and the storage battery (5) jointly supply power, and the output power of the storage battery (5) is P ba ＝P load -P fc_max -P pv_max The method comprises the steps of carrying out a first treatment on the surface of the If P ba +P fc_max +P pv_max <P load The combined power supply of the fuel cell generator set (12), the photovoltaic cell generator set (11) and the storage battery (5) is insufficient to meet the load power requirement, the diesel engine generator set (14) is required to be combined, and the output power of the diesel engine generator set (14) is P diesel ＝P load -P fc_max -P pv_max -P ba The method comprises the steps of carrying out a first treatment on the surface of the If P diesel +P fc_max +P pv_max +P ba <P load The method comprises the steps that if the output power of a fuel cell generator set (12), a photovoltaic cell generator set (11), a storage battery (5) and a diesel engine generator set (14) can not meet the load power requirement, whether a controllable load exists at a load end is checked, and if the controllable load exists, the controllable load is cut off and the overload is prompted; if the controllable load does not exist, the load end control switch is cut off, power supply is stopped, and the overload is prompted; the above operation mode is a control method of the whole micro-grid system in normal operation.
2. The mobile multi-energy micro-grid control method according to claim 1, wherein in S3, the control method for suddenly decreasing the load power of the micro-grid system is as follows: current load power P load When P is compared with the output power of the power generation unit at the power generation side fc +P pv +P diesel >P load If SOC is at<SOC max The diesel generator set (14) continues to work, the storage battery (5) stops working and enters a charging state, and the storage battery (5) is utilized to absorb redundant power for charging; if SOC is greater than or equal to SOC max The method is characterized in that when the energy storage capacity of the storage battery (5) is insufficient to maintain power balance or the energy storage device (13) is charged and saturated, the diesel generator set (14) enters a shutdown state, and the storage battery (5) works instead of the diesel generator set (14);
when P fc +P pv +P diesel <P load If SOC is at>SOC min The storage battery (5), the fuel cell generator set (12), the diesel engine generator set (14) and the photovoltaic cell generator set (11) supply power to the load together; if SOC is less than or equal to SOC min Judging whether a controllable load exists in the micro-grid system or not, if the controllable load exists in the micro-grid system, cutting off the controllable load, and prompting that the load is overlarge; if no controllable load exists in the system, the cut-off switch stops supplying power to prompt that the load is overlarge.
3. The mobile multi-energy micro-grid control method according to claim 1, wherein in S3, the control method for suddenly increasing the load power of the micro-grid system is as follows: when P fc +P pv +P diesel +P ba <P load Judging whether a controllable load exists in the micro-grid system or not, and if the controllable load exists at the load end, cutting off the controllable load by the control system to prompt that the load is overlarge; if the load end does not have the controllable load, the control system cuts off a switch of the load end, stops power supply and prompts that the load is overlarge.
4. The mobile multi-energy micro-grid control method according to claim 1, wherein in S3, the method for controlling the occurrence of an abnormality in the power generating end of the micro-grid system is as follows: the connection between the power generation unit with the fault and the power distribution system is disconnected in an emergency way, and the power generation unit is prompted to be faulty; at the same time judging the total power P of other power generation units total If P is the condition that whether the whole micro-grid system can be supported to work normally total >P load The remaining power generation units can be supported and only the connection between the problematic power generation unit and the power distribution system is disconnected; if P total <P load Judging whether a controllable load exists at the output load end, if so, disconnecting the controllable load and prompting that the load is overlarge; if no controllable load exists, the switch of the load end (3) is disconnected to stop power supply, and the overload is prompted.
5. The mobile multi-energy micro-grid control method according to claim 1, wherein in S3, the method for regulating and controlling black start of the micro-grid system is as follows: detecting the current SOC of the storage battery (5), if the current SOC is >SOC min The diesel generator set (14) and the storage battery (5) are used for jointly supplying power, and the electric energy is limited and only supports important loads and drives other power generation units to generate power; if SOC is<SOC min The diesel generator set (14) singly works to output power, and the storage battery is stopped from charging and discharging; after the black start, the diesel generator set (14) and the storage battery (5) or the diesel generator set (14) drive the fuel cell (12) and the photovoltaic cell generator set (11) to start, and the starting stage is restarted to recover to the normal working process, and the working modes of the first stage and the second stage are returned.
6. A mobile multi-energy micro-grid system for implementing the mobile multi-energy micro-grid control method according to claim 1, which is characterized by comprising a direct current side DG unit (1), a power distribution system (2), an output load end (3) and a micro-grid central control system (4); the direct current side DG unit (1) comprises a photovoltaic cell generator set (11), a fuel cell generator set (12), an energy storage device (13) and a diesel engine generator set (14); the power distribution system (2) comprises a low-voltage direct-current bus, a medium-voltage direct-current bus and an alternating-current bus, wherein the low-voltage direct-current bus is respectively connected with a first DC-DC converter (15), a second DC-DC converter (16), a bidirectional circulating DC-DC converter (17) and an AC-DC converter (18) of the direct-current side DG unit (1), the low-voltage direct-current bus is connected with the medium-voltage direct-current bus through a booster (21), and the medium-voltage direct-current bus is connected with the output load end (3); the output load end (3) comprises an alternating current load and a direct current load; the micro-grid central control system (4) is respectively connected with each component in the direct current side DG unit (1), the power distribution system (2) and the output load end (3) through the CAN bus, and controls the work switching of the direct current side DG unit (1), the power distribution system (2) and the output load end (3).
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