WO2024179099A1 - 一种微电网系统 - Google Patents

一种微电网系统 Download PDF

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Publication number
WO2024179099A1
WO2024179099A1 PCT/CN2023/136143 CN2023136143W WO2024179099A1 WO 2024179099 A1 WO2024179099 A1 WO 2024179099A1 CN 2023136143 W CN2023136143 W CN 2023136143W WO 2024179099 A1 WO2024179099 A1 WO 2024179099A1
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WO
WIPO (PCT)
Prior art keywords
power generation
power
bus
photovoltaic
energy storage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2023/136143
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English (en)
French (fr)
Inventor
张灵杰
毛亚辉
佘宏武
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Huawei Digital Power Technologies Co Ltd
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Huawei Digital Power Technologies Co Ltd
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Publication date
Application filed by Huawei Digital Power Technologies Co Ltd filed Critical Huawei Digital Power Technologies Co Ltd
Priority to EP23925045.9A priority Critical patent/EP4657698A4/en
Publication of WO2024179099A1 publication Critical patent/WO2024179099A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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
    • H02J3/001—Arrangements for handling faults or abnormalities, e.g. emergencies or contingencies
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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 networks by storage of energy
    • H02J3/32—Arrangements for balancing of the load in networks by storage of energy using batteries or super capacitors with converting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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 feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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 feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
    • H02J7/34—Parallel operation in networks using both storage and other DC sources, e.g. providing buffering
    • H02J7/35—Parallel operation in networks using both storage and other DC sources, e.g. providing buffering with light sensitive cells
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/062—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for AC powered loads
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/068—Electronic means for switching from one power supply to another power supply, e.g. to avoid parallel connection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2101/00—Supply or distribution of decentralised, dispersed or local electric power generation
    • H02J2101/20—Dispersed power generation using renewable energy sources
    • H02J2101/22—Solar energy
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2101/00—Supply or distribution of decentralised, dispersed or local electric power generation
    • H02J2101/20—Dispersed power generation using renewable energy sources
    • H02J2101/22—Solar energy
    • H02J2101/24—Photovoltaics
    • 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

Definitions

  • the present application relates to a microgrid system.
  • the photovoltaic and storage AC coupled microgrid system has always been the mainstream microgrid system structure due to its good scalability and other advantages. Since voltage fluctuations, fault ride-through and other emergencies may occur during the operation of the microgrid system, the secondary monitoring systems such as the microgrid controller, sub-array data acquisition, and battery control equipment in the microgrid system generally need to be powered by UPS or directly drawn from the microgrid to ensure its operation.
  • the microgrid has two options: 1) configure a diesel generator to maintain the power supply; 2) shut down the microgrid and retain enough energy storage SOC (State of Charge) to support it until the weather recovers. It can support the power consumption of the black start and wait for the weather to recover the next morning, and the PV (Photo Voltaic) can generate electricity before starting the system.
  • SOC State of Charge
  • Diesel generator sets require a large workload for operation and maintenance, require high technical capabilities, are complex to manage, and have high fuel costs, which are not conducive to their use in some remote or underdeveloped areas. De-oiling is a preferred power supply solution for such areas.
  • the UPS and microgrid monitoring system will soon shut down due to power outage.
  • the microgrid system lacks the ability or mechanism to self-start and self-recover, and can only continue to be in a power outage state, or has to rely on operation and maintenance personnel to restart the microgrid system, resulting in high power outage and operation and maintenance costs for the microgrid, especially for small low-voltage microgrid systems, which face greater operation and maintenance pressure and poor user experience.
  • an embodiment of the present application provides a microgrid system.
  • the present application provides a microgrid system, including: a first photovoltaic power generation system, an AC bus, a UPS (Uninterrupted Power System), a first switch and a second switch;
  • the first photovoltaic power generation system includes at least one first photovoltaic power generation unit and at least one first photovoltaic inverter, which is connected to the UPS through the first switch and connected to the AC bus through the second switch, and is used to supply power to the UPS through the first switch or to supply power to the AC bus through the second switch;
  • the AC bus is connected to the UPS through the first switch, and is used to supply power to the UPS when power is turned on.
  • the UPS is usually used to provide stable and uninterrupted AC power, and it is usually equipped with a battery to ensure that when its own external power supply is unstable or stops supplying power, it can still maintain uninterrupted stable AC power output for a period of time.
  • the microgrid cannot work, and the control and management units in the microgrid continue to work for a period of time by the UPS, but after the power in the UPS battery is exhausted, the UPS also stops supplying power to them.
  • the entire microgrid system including the control and management units stops running.
  • the control and management units in the system must be activated, such as the system controller in the embodiment of the present application.
  • the corresponding startup control can be taken according to the specific conditions of the power generation system (such as the photovoltaic power generation system in the embodiment of the present application) and the energy storage system (such as the energy storage power supply system in the embodiment of the present application) in the microgrid, so that the microgrid can be restored to normal power supply.
  • the UPS is first automatically directly or indirectly activated, and then the various control and management units are activated through the UPS, and then the photovoltaic power generation system and the energy storage power supply system are activated to work, and finally the self-starting of the microgrid is realized.
  • the UPS is first automatically directly or indirectly activated, and then the various control and management units are activated through the UPS, and then the photovoltaic power generation system and the energy storage power supply system are activated to work, and finally the self-starting of the microgrid is realized.
  • there may be multiple photovoltaic power generation systems in the power supply system of the microgrid and they generally directly supply power to the AC bus.
  • a power supply line is drawn from one of the photovoltaic power generation systems to the UPS, so that the photovoltaic power generation system can supply power to the UPS in addition to the AC bus.
  • the UPS When the photovoltaic power generation system has the power generation capacity, the UPS can be activated at the first time, and then the UPS can activate the system controller. The system controller then determines the timing of restarting the microgrid according to the overall situation of other photovoltaic power generation systems and energy storage power supply systems, and restarts the microgrid when the power supply of light and storage is sufficient.
  • This system architecture design that can realize the self-starting of the microgrid system cleverly utilizes the function of autonomous power generation of the photovoltaic power generation system, does not need to make too many adjustments to the microgrid system, and does not need to configure other power supply equipment or controllers, and can realize the self-starting function of the microgrid system at the lowest cost.
  • the first photovoltaic power generation system in the embodiment of the present application can be any one of the photovoltaic power generation systems.
  • the first photovoltaic power generation system needs to be used to directly activate the UPS through a relay and can be set at a location closer to the UPS to save line costs and current transmission losses.
  • the first switch includes a first contact KA1 and a second contact KA2; the first photovoltaic power generation system is connected to the UPS through the second contact KA2; and the AC bus is connected to the UPS through the first contact KA1.
  • the first contact KA1 is used to open when the AC bus is powered on, and to close when the AC bus is powered on; the second contact KA2 is used to close when the AC bus is powered on, and to open when the AC bus is powered on.
  • the first photovoltaic power generation system when the available power generation power of the first photovoltaic power generation system is greater than the first photovoltaic power supply threshold, the first photovoltaic power generation system supplies power to the AC bus through the second switch, so that the AC bus supplies power to the UPS through the first contact KA1; or, when the available power generation power of the first photovoltaic power generation system is greater than or equal to the first photovoltaic power supply threshold, the first photovoltaic power generation system supplies power to the UPS through the second contact KA2.
  • a fifth possible embodiment if the second switch is in an off state, when the available power generation power of the first photovoltaic power generation system is greater than or equal to the first photovoltaic power supply threshold, the first photovoltaic power generation system supplies power to the UPS through the second contact KA2.
  • a sixth possible embodiment if the second switch is in a closed state, when the available power generation power of the first photovoltaic power generation system is greater than the first photovoltaic power supply threshold, the first photovoltaic power generation system supplies power to the AC bus through the second switch, so that the AC bus passes through the first contact KA1 Power is supplied to the UPS.
  • the second switch adopts a normally closed switch, when the AC bus is in a power-off state, the second switch is in a closed state.
  • the AC bus is quickly energized, the first contact KA1 of the relay is turned on, and the second contact KA2 is turned off.
  • the first photovoltaic power generation system indirectly supplies power to the UPS through the AC bus; if the second switch adopts a normally open switch, when the AC bus is in a disconnected state, the second switch is in a disconnected state.
  • the available power generation power of the first photovoltaic power generation system is greater than the first photovoltaic power supply threshold and starts to supply power to the outside, the supplied current flows to the UPS through the second contact KA2, thereby powering on the UPS.
  • the design of the relay is not only to realize the two scenarios in which the first photovoltaic power generation system directly or indirectly supplies power to the UPS, but also to automatically switch to the state in which the first contact KA1 is disconnected and the second contact KA2 is connected when a circuit fault occurs on the AC bus side during the operation of the microgrid. This not only ensures the safety of other units in the microgrid, but also maintains power supply to the UPS, that is, maintains power supply to the monitoring and management system, making it easier to continue to observe the situation of the entire microgrid through the monitoring and management system.
  • a seventh possible embodiment it further includes at least one second photovoltaic power generation system and a system controller;
  • the UPS is connected to the system controller for supplying power to the system controller;
  • each of the second photovoltaic power generation systems includes at least one second photovoltaic power generation unit and at least one second photovoltaic inverter for supplying power to the AC bus;
  • the system controller is used to control the first photovoltaic power generation system and/or the second photovoltaic power generation system to supply power to the AC bus.
  • the microgrid system can have multiple photovoltaic power generation systems, so that the microgrid has a more sufficient power supply source; in addition, by configuring the system controller, each photovoltaic power generation system can be better supervised and controlled, so as to realize flexible scheduling of the power supply in the microgrid.
  • one of the photovoltaic power generation systems that is, the first photovoltaic power generation system
  • the first photovoltaic power generation system is selected, so that it has a self-starting function, so that when its available power generation reaches the first power supply threshold, it automatically supplies power to the AC bus or UPS, so that the UPS can supply power to the system controller, so that when the system and external environmental conditions meet the conditions for the photovoltaic power generation system to supply power to the outside, the system controller can quickly resume work, and then, the system controller can further control other photovoltaic power generation systems according to pre-set conditions or manual control, that is, the second photovoltaic power generation system supplies power to the AC bus.
  • the system controller can synchronously control the second switch to close, so that the first photovoltaic power generation system can also switch to supply power to the AC bus, and thereafter, the UPS switches to take power from the AC bus.
  • it further includes at least one energy storage power supply system;
  • the energy storage power supply system includes at least one energy storage unit and at least one energy storage converter, which is used to supply power to the AC bus or receive power from the AC bus;
  • the system controller is also used to control the energy storage power supply system to supply power to the AC bus, or to control the AC bus to supply power to the energy storage power supply system.
  • the microgrid can also be equipped with an energy storage power supply system to maintain the stable power supply of the microgrid when the photovoltaic power generation system cannot generate electricity at night or the photovoltaic power generation system generates insufficient electricity when the weather conditions are bad. Therefore, when the energy storage power supply system has sufficient storage capacity, the system controller can dispatch the energy storage power supply system to supply power to the AC bus; if the energy storage power supply system has insufficient storage capacity, the system controller can also use the AC bus to supply power to the energy storage power supply system, and when its storage capacity is high enough, it can be used to supply power to the AC bus.
  • the system controller is used to: when the sum of the available power generation power of the first photovoltaic power generation system and the second photovoltaic power generation system is greater than a second photovoltaic power supply threshold, control the first photovoltaic power generation system and/or the second photovoltaic power generation system to supply power to the AC bus, and control the AC bus to supply power to the energy storage power supply system, so as to restore the energy storage power supply system to an operating state.
  • the energy storage power supply system will generate certain power consumption during operation. Therefore, if the energy storage power supply system is to be further started, the available power generation power of all photovoltaic power generation systems must be able to cover the power consumption of the energy storage power supply system. Only under such conditions can the overall operation of the microgrid be guaranteed not to be in a state of power shortage.
  • the system controller is used to: when the energy storage power supply system is in an operating state, if the storage amount of the energy storage power supply system is greater than or equal to the energy storage power supply threshold, control the energy storage power supply system to supply power to the AC bus; or, when the energy storage power supply system is in an operating state, if the storage amount of the energy storage power supply system is less than the energy storage power supply threshold, control the AC bus to charge the energy storage power supply system.
  • the system controller will further determine whether to control the energy storage power supply system to supply power to the AC bus or to control the AC bus to charge the energy storage power supply system based on the storage power of the energy storage power supply system, which is actually the SOC of its energy storage unit.
  • the microgrid system provided in the embodiment of the present application can automatically restore the operation of the supervision and control system when light is restored after a power outage in the microgrid, without the need for manual operation and maintenance.
  • the AC-coupled photovoltaic power generation system can maximize the utilization of the electrical energy in the energy storage battery, without having to worry about the problem of not being able to start after a power outage.
  • FIG1 is a microgrid system provided by an embodiment of the present application.
  • FIG2 is another microgrid system provided in an embodiment of the present application.
  • FIG3 is another microgrid system provided in an embodiment of the present application.
  • Microgrid systems are usually used to provide continuous and stable power supply to various loads in an off-grid (separated from the power grid) state.
  • microgrids can also be connected to the grid (connected to the power grid), and the embodiments of this application do not impose specific restrictions.
  • the ultimate source of power supply for microgrids is photovoltaic power generation.
  • photovoltaic power generation By configuring a photovoltaic power generation system, the direct current generated by solar photovoltaic panels is converted into alternating current and input into the power grid, and then the power grid supplies power to the load.
  • microgrids will also match some energy storage systems. When there is surplus electricity from photovoltaic power generation, the energy storage system will store the surplus electricity.
  • the energy storage system When the photovoltaic power generation is insufficient or zero, the energy storage system will supply power to the microgrid to achieve stable power supply to the microgrid.
  • This mutual dispatch of power supply needs to be coordinated by a control center (such as a supervision and management system), and the normal operation of the microgrid needs to be based on the normal operation of the control center.
  • the microgrid system provided in the present application is suitable for solving the problem that the microgrid cannot automatically start up and restore power supply to the microgrid after light is restored after a power outage. Furthermore, during the startup process, it can accurately determine when to start up the photovoltaic storage equipment and resume operation, thereby reducing the energy consumption caused by blind startup or startup failure due to insufficient power generation capacity.
  • the photovoltaic power generation system can not only supply power to the microgrid during its normal operation, but also, after a power outage in the microgrid, when the photovoltaic power generation system has the power generation capacity, first supply power to the UPS, and then the UPS supplies power to the system controller, thereby ultimately achieving self-recovery and self-starting of the microgrid under the control of the system controller.
  • Figure 1 of the specification exemplarily shows a microgrid system provided by an embodiment of the present application.
  • the system includes a first photovoltaic power generation system, an AC bus, a UPS (Uninterrupted Power System), a first switch and a second switch.
  • UPS Uninterrupted Power System
  • the first photovoltaic power generation system includes a first photovoltaic power generation unit and a first photovoltaic inverter.
  • the first photovoltaic power generation system is connected to the UPS through the first switch, and is connected to the AC bus through the second switch.
  • the first photovoltaic power generation system can supply power to the UPS through the first switch, and can also supply power to the AC bus through the second switch.
  • the AC bus is also connected to the UPS through the first switch, and when the AC bus is energized, it can be used to supply power to the UPS.
  • the UPS After the UPS is powered, it is activated to work.
  • the UPS is usually also equipped with a battery. When the external power supply to the UPS is unstable, the UPS can still output a stable 220V AC power to the outside. In this way, under the power supply of the UPS, other supervision and control units of the microgrid can work normally.
  • the first switch includes a first contact KA1 and a second contact KA2.
  • the first photovoltaic power generation system is connected to the UPS through the second contact KA2, and the AC bus is connected to the UPS through the first contact KA1; when the AC bus is powered off, the first contact KA1 is disconnected and the second contact KA2 is closed, and the first photovoltaic power generation system can supply power to the UPS; when the AC bus is powered on, the first contact KA1 is closed and the second contact KA2 is turned off, and the AC bus can supply power to the UPS.
  • the first switch in the embodiment of the present application can be an ordinary knob switch, and the opening or closing of the first contact KA1 and the second contact KA2 can be realized by manual control, or it can be a relay, and the opening or closing of the first contact KA1 and the second contact KA2 is realized by the charged adsorption of the coil of the relay (not shown in the figure).
  • the UPS can supply power to other possible devices in the microgrid, such as units responsible for monitoring and management.
  • the first photovoltaic power generation system has two paths for supplying power to the UPS, wherein the first path is: supplying power through the second switch item AC bus, so that the AC bus can supply power to the UPS through the first contact KA1; the second path is: directly supplying power to the UPS through the second contact KA2.
  • the prerequisite for the first photovoltaic power generation system to directly or indirectly supply power to the UPS is that the available power generation power of the first photovoltaic power generation system is greater than or equal to the first photovoltaic power supply threshold.
  • the first photovoltaic inverter in the first photovoltaic power generation system can automatically detect the voltage at the PV (Photovoltaic) input terminal.
  • the available power generation power that the first photovoltaic power generation system can provide reaches a level greater than or equal to the first photovoltaic power supply threshold.
  • the first photovoltaic inverter will automatically start to run and convert the DC power at the PV input terminal into AC power for external output.
  • the value of the first photovoltaic power supply threshold can be set according to the external power supply requirements of the UPS, and the embodiments of the present application are not specifically limited.
  • the first photovoltaic power generation system supplies power to the UPS through path one or path two depends on the on-off state of the second switch. For example, if the second switch is in an off state, when the first photovoltaic power generation system meets the power supply condition, that is, when the available power generation power of the first photovoltaic power generation system is greater than the first photovoltaic power supply threshold, power will be supplied to the UPS through the second contact KA2; if the second switch is in a closed state, when the first photovoltaic power generation system meets the power supply condition, that is, when the available power generation power of the first photovoltaic power generation system is greater than the first photovoltaic power supply threshold, power will be supplied to the UPS through the second contact KA2; When the available power generation is greater than the first photovoltaic power supply threshold, the second switch will be used to supply power to the AC bus, and the AC bus will then supply power to the UPS through the first contact KA1.
  • the second switch can be set to a normally open switch.
  • the second switch When the microgrid is in a power-off state, without the system controller or artificial external force to close it, the second switch will be in an open state.
  • the UPS When the first photovoltaic power generation system reaches the power supply condition, that is, when the available power generation of the first photovoltaic power generation system is greater than the first photovoltaic power supply threshold, the UPS will be supplied with power through the second contact KA2; similarly, if the second switch is set to a normally closed switch, without the system controller or artificial external force to disconnect it, the second switch will be in a closed state.
  • the AC bus will be supplied with power through the second switch, and the AC bus will then supply power to the UPS through the first contact KA1.
  • the opening or closing of the second switch through other switch devices with similar functions, and the embodiment of the present application does not impose specific restrictions on the selection of the second switch.
  • another microgrid system provided by the embodiment of the present application also includes at least one second photovoltaic power generation system and a system controller.
  • UPS is connected to the system controller for supplying power to the system controller.
  • the second photovoltaic power generation system includes a second photovoltaic power generation unit and a second photovoltaic inverter for supplying power to the AC bus.
  • the system controller is communicatively connected with the first photovoltaic power supply system, the second photovoltaic power supply system and the second switch, and can control the opening or closing of the second switch, and is used to control the first photovoltaic power generation system and/or the second photovoltaic power generation system to supply power to the AC bus.
  • the system controller can first control the second quick-closed switch to close, and then control the first photovoltaic power generation system and the second photovoltaic power generation system to supply power to the AC bus together;
  • the second switch is a normally closed switch, the first photovoltaic power generation system can have a self-starting function, and the first photovoltaic power generation system and the AC bus are in a conductive state.
  • the first photovoltaic power generation system can automatically supply power directly or indirectly to the AC bus, and the system controller can continue to control the second photovoltaic power generation system to supply power to the AC bus, thereby realizing that the first photovoltaic power generation system and the second photovoltaic power generation system supply power to the AC bus.
  • a basic function of the second switch is to quickly disconnect the circuit when a fault occurs at either end of the second switch to ensure that the other circuit is not affected. Therefore, in actual application, all photovoltaic power generation systems can be configured with a second switch.
  • the embodiments of the present application only exemplify the impact of the second switch corresponding to the first photovoltaic power supply system on the self-starting of the microgrid system.
  • the microgrid system may also include at least one energy storage power supply system.
  • the introduction of the energy storage power supply system can improve the stability of the power supply. When the storage capacity is large enough, it can maintain the continuous power supply to the microgrid when the photovoltaic power generation system does not have the conditions for power generation (such as at night).
  • the energy storage power supply system may have one or more energy storage units and one or more energy storage inverters.
  • the energy storage unit is used to store electricity, and lithium iron phosphate batteries or lead-acid batteries may be used.
  • the embodiments of the present application do not impose specific restrictions on the specific type of battery.
  • the energy storage inverter can convert the direct current output of the energy storage unit into alternating current and output it to the AC bus, so that the energy storage power supply system supplies power to the AC bus. It can also convert the alternating current input to the AC bus into direct current and input it to the energy storage unit, so that the AC bus charges the energy storage power supply system.
  • the prerequisite for the energy storage power supply system to charge or discharge is that the energy storage power supply system should be in operation.
  • the operation process will generate a certain amount of power consumption.
  • the system controller needs to control the AC bus to supply power to the energy storage power supply system to wake up the energy storage power supply system and start it into operation.
  • the prerequisite for the system controller to control the AC bus to supply power to the energy storage power supply system is that the available power generation of the first photovoltaic power generation system and the second photovoltaic power generation system needs to be greater than the power consumption of the energy storage power supply system itself, otherwise the microgrid as a whole will be in a power-deficient state after the energy storage power supply system wakes up.
  • the second photovoltaic power supply threshold when the sum of the available power generation power of the first photovoltaic power generation system and the second photovoltaic power generation system is greater than the second photovoltaic power supply threshold, the first photovoltaic power generation system and/or the second photovoltaic power generation system can be controlled to supply power to the AC bus, and the AC bus can supply power to the energy storage power supply system, so that the energy storage power supply system starts to enter the operating state, thereby realizing the awakening of the energy storage power supply system.
  • the energy storage power supply system can be used as the power supply source of the microgrid, so that the load powered by the microgrid can operate more stably and safely.
  • the premise of using the energy storage power supply system for power supply is that the energy storage power supply system itself has a certain amount of storage capacity.
  • an energy storage power supply threshold can be set for the energy storage power supply system.
  • the system controller can control the energy storage power supply system to supply power to the AC bus; if the storage capacity of the energy storage power supply system is less than the energy storage power supply threshold, the AC bus can be controlled to charge the energy storage power supply system.
  • this control is more flexible.
  • the energy storage power supply system with high storage capacity can stably supply power to the AC bus, and the energy storage power supply system with less remaining storage capacity can be charged by the AC bus to increase the storage capacity.

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Abstract

本申请提供一种微电网系统。该系统包括第一光伏发电系统、交流母线、UPS(Uninterrupted Power System，不间断电源)、第一开关和第二开关。在光伏发电系统具备发电条件时，通过第一光伏供电系统直接或间接地向UPS供电，激活UPS后通过UPS向微电网系统的监管、控制等单元供电，进而使得系统控制器可以控制微电网中的其它储能供电系统和光伏发电系统启动，从而实现整个微电网自启动恢复到正常稳定运行的状态。

Description

一种微电网系统
本申请要求于2023年2月28日提交中国专利局、申请号为202310223567.4、申请名称为“一种微电网系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及一种微电网系统。
背景技术
光、储交流耦合的微电网系统，由于其良好的可扩展性等优势，一直是主流的微电网系统结构。由于微电网系统运行中可能发生电压波动、故障穿越等突发情况，微电网系统中的微电网控制器、子阵数采、电池控制设备等二次监控系统，一般需要通过UPS供电或直接从微电网取电来保障其运行。
微电网在运行中，当遇到不良天气储能系统中的电能不足时，微电网无法继续维持系统运行，因此微电网有两种选择：1)配置柴油发电机发来维持电能供应；2)关停微电网，保留足够储能SOC(State of Charge，剩余电量)，支撑到天气恢复之后，可支撑黑启动对电量的消耗，等待次日早上天气恢复之后，PV(Photo Voltaic，光伏)可发出电能之后再开机运行。
柴油发电机组运维检修工作量大、技术能力要求高、管理复杂、油费高，不利于一些偏远或欠发达地区的使用，去油化是这类地区的一种优选的供电方案。
然而，微电网因故障或电能不足而全网停电之后，UPS及微电网监控系统也很快亏电关机，在次日条件满足(光照恢复)的情况下，微电网系统因缺乏自启动、自恢复的能力或机制，只能继续处于停电状态，或不得不依赖运维人员来重新开启微电网系统，使得微电网的停电、运维成本较高，特别是对于小型低压微电网系统，面临较大的运维压力，用户体验较差。
在微电网具备恢复运行条件后，让光储交流耦合微电网能够及时自启动、自恢复十分有必要。
发明内容
为了解决现有微电网黑启动方式依赖蓄电池剩余电量和柴油发电机剩余油料的问题，本申请实施例提供了一种微电网系统。
第一方面，在第一种可能的实施例中，本申请提供了一种微电网系统，包括：第一光伏发电系统、交流母线、UPS(Uninterrupted Power System，不间断电源)、第一开关和第二开关；所述第一光伏发电系统，包括至少一个第一光伏发电单元和至少一个第一光伏逆变器，通过所述第一开关与所述UPS连接，并通过第二开关与所述交流母线连接，用于通过所述第一开关向所述UPS供电或通过所述第二开关向所述交流母线供电；所述交流母线，通过所述第一开关与所述UPS连接，用于通电时向所述UPS供电。
可以理解的是，微电网的自启动过程，通常要经过几个步骤，按照顺序依次实现各个单 元的启动，最终实现整个微电网重新开始正常运行。UPS通常用于提供稳定不间断的交流电，其本身通常配置有一个蓄电池，以保证其自身外部电源不稳定或停止供电时，还能维持一段时间输出不间断的稳定交流电。在微电网不工作期间，如夜间光伏发电系统不具备发电条件且储能系统也缺电无法向微电网供电时，微电网无法工作，微电网中起到控制、管理的单元由UPS继续维持一段工作时间，但UPS的蓄电池中的电量被耗尽后，UPS也停止向它们供电，此时，包括控制、管理单元在内的整个微电网系统停止运行。当微电网具备运行条件，如白天光照充足时，需要重新启动微电网的运行，首先便先要激活系统中的控制、管理单元，如本申请实施例中的系统控制器，当微电网中的控制、管理单元被通电激活后，便可以根据微电网中发电系统(如本申请实施例中的光伏发电系统)、储能系统(如本申请实施例中的储能供电系统)的具体情况采取相应的启动控制，使微电网重新恢复正常供电状态。在本申请的实施例中，通常选择在光伏发电系统具备发电能力时，首先自动直接或间接地激活UPS，再通过UPS激活各个控制、管理单元，随后再激活光伏发电系统、储能供电系统工作，最终实现微电网的自启动。应理解，微电网的供电系统中，可能存在多个光伏发电系统，它们一一般直接向交流母线供电，而本申请实施例通过从其中一个光伏发电系统中引出一条供电线给UPS，使得该光伏发电系统除了可以向交流母线供电外，还可以向UPS供电，在该光伏发电系统具备发电能力时，可以第一时间激活UPS，进而使UPS能够激活系统控制器，系统控制器再根据其它光伏发电系统和储能供电系统的整体情况，判断重新启动微电网的时机，在光、储的供电都足够时，重新启动微网。这种可以实现微电网系统自启动的系统架构设计，巧妙地利用了光伏发电系统自主发电的功能，不用对微电网系统进行过多的调整、也不需要额外配置其它供电设备或者控制器，能在成本最低的前提下，实现微电网系统具备自启动功能。应理解，本申请实施例中的第一光伏发电系统可以是光伏发电系统中的任意一个，在实际运用中，第一光伏发电系统需要用来通过继电器直接激活UPS，可以设置得离UPS较近的位置，以节约线路成本以及电流传输的损耗。
结合第一方面第一种可能的实施例，在第二种可能的实施例中，所述第一开关包括第一触点KA1和第二触点KA2；所述第一光伏发电系统，通过所述第二触点KA2与所述UPS连接；所述交流母线，通过所述第一触点KA1与所述UPS连接。
结合第一方面第一种或第二种可能的实施例，在第三种可能的实施例中，所述第一触点KA1，用于当所述交流母线断电时断开，当所述交流母线通电时闭合；所述第二触点KA2，用于当所述交流母线断电时闭合，当所述交流母线通电时断开。
结合第一方面第二种或第三种可能的实施例，在第四种可能的实施例中，当所述第一光伏发电系统的可用发电功率大于第一光伏供电阈值时，所述第一光伏发电系统通过所述第二开关向所述交流母线供电，以使所述交流母线通过所述第一触点KA1向所述UPS供电；或者，当所述第一光伏发电系统的可用发电功率大于或等于第一光伏供电阈值时，所述第一光伏发电系统通过所述第二触点KA2向所述UPS供电。
结合第一方面第四种可能的实施例，在第五种可能的实施例中，若所述第二开关处于断开状态，当所述第一光伏发电系统的可用发电功率大于或等于第一光伏供电阈值时，所述第一光伏发电系统通过所述第二触点KA2向所述UPS供电。
结合第一方面第四种可能的实施例，在第六种可能的实施例中，若所述第二开关处于闭合状态，当所述第一光伏发电系统的可用发电功率大于第一光伏供电阈值时，所述第一光伏发电系统通过所述第二开关向所述交流母线供电，以使所述交流母线通过所述第一触点KA1 向所述UPS供电。
应理解，第二开关若采用常闭型开关，当交流母线处于断电状态时，第二开关处于闭合状态，当第一光伏发电系统的可用发电功率大于第一光伏供电阈值，开始对外供电后，交流母线上迅速通电，继电器的第一触点KA1导通，第二触点KA2断开，此时，第一光伏发电系统通过交流母线间接地向UPS供电；第二开关若采用常开型开关，当交流母线处于断开状态时，第二开关处于断开状态，当第一光伏发电系统的可用发电功率大于第一光伏供电阈值，开始对外供电后，所供电流通过第二触点KA2流向UPS，实现UPS上电。
需要说明的是，继电器的设计，不仅仅为了实现两种场景下，第一光伏发电系统直接或间接地向UPS供电，还可以在微电网运行过程中，交流母线侧的电路出现故障的时候，自动切换为第一触点KA1断开，第二触点KA2导通的状态，既保障了微电网其它单元的安全，又可以维持对UPS，也就是维持对监控、管理系统的供电，便于继续通过监控、管理系统观察整个微电网的情况。
结合第一方面第一种到第六种任一种可能的实施例，在第七种可能的实施例中，还包括至少一个第二光伏发电系统和系统控制器；所述UPS与所述系统控制器连接，用于向所述系统控制器供电；每个所述第二光伏发电系统，包括至少一个第二光伏发电单元和至少一个第二光伏逆变器，用于向所述交流母线供电；所述系统控制器，用于控制所述第一光伏发电系统和/或所述第二光伏发电系统向所述交流母线供电。
应理解，微电网系统可以拥有多个光伏发电系统，使得微电网有更充足的供电来源；另外，通过配置系统控制器，可以更好地对各个光伏发电系统进行监管和控制，便于实现对微电网中的电力供应实现灵活的调度。在本申请提供的可能的实施例中，选择了其中一个光伏发电系统，亦即第一光伏发电系统，让它具有自启动的功能，使它的可用发电功率达到第一供电阈值时，便自动对交流母线或UPS供电，使得UPS可以向系统控制器供电，实现在系统和外部环境条件满足光伏发电系统对外供电的条件时，系统控制器能够快速地恢复工作，进而，系统控制器可以根据预先设定的条件或者人为的控制，进一步控制其它光伏发电系统，亦即第二光伏发电系统向交流母线供电，此时，若第一光伏发电系统与交流母线的线路未导通，亦即第二开关处于断开状态时，系统控制器可以同步控制第二开关闭合，使得第一光伏发电系统也可以转而向交流母线供电，此后，UPS转而从交流母线取电。
结合第一方面第一种到第七种任一种可能的实施例，在第八种可能的实施例中，还包括至少一个储能供电系统；所述储能供电系统，包括至少一个储能单元和至少一个储能变流器，用于向所述交流母线供电或者接受所述交流母线的供电；所述系统控制器，还用于控制所述储能供电系统向所述交流母线供电，或者，用于控制所述交流母线向所述储能供电系统供电。
应理解，微电网中也可以通过设置储能供电系统来实现夜间光伏发电系统无法发电或者天气状况不良时光伏发电系统发电不足时，保持微电网的稳定供电。因此，当储能供电系统的储电量足够时，系统控制器可以调度储能供电系统向交流母线供电；若储能供电系统的储电量不足时，系统控制器也可以交流母线向储能供电系统供电，当其储电量足够高后，再用来向交流母线供电。
结合第一方面第八种可能的实施例，在第九种可能的实施例中，所述系统控制器用于：当所述第一光伏发电系统和所述第二光伏发电系统的可用发电功率之和大于第二光伏供电阈值时，控制所述第一光伏发电系统和/或所述第二光伏发电系统向所述交流母线供电，并控制所述交流母线向所述储能供电系统供电，以使所述储能供电系统恢复运行状态。
应理解，储能供电系统在运行过程中会产生一定的功耗，因此，若要进一步启动储能供电系统，需要所有光伏发电系统的可用发电功率能够覆盖储能供电系统的功耗，在这种条件下的启动才能保证微电网的整体运行不会处于亏电的状态。
结合第一方面第八种或第九种可能的实施例，在第十种可能的实施例中，所述系统控制器用于：当所述储能供电系统处于运行状态时，若所述储能供电系统的储电量大于或等于储能供电阈值时，控制所述储能供电系统向所述交流母线供电；或者，当所述储能供电系统处于运行状态时，若所述储能供电系统的储电量小于储能供电阈值时，控制所述交流母线向所述储能供电系统充电。
应理解，储能供电系统恢复运行后，还需要考虑其储能单元的SOC(剩余电量，State of Charge)来决定要控制其对外供电还是需要外部对其进行充电。在本申请提供的一种可能的实施例中，系统控制器会进一步根据储能供电系统的储电量，实际上也就是其储能单元的SOC，来确定控制储能供电系统向交流母线供电还是控制交流母线向储能供电系统充电。
本申请实施例提供的微电网系统，可以实现在微电网停电后，在光照恢复时，自动先恢复监管、控制系统的运行，无需人工运维，并通过设置系统各单元的启动时机，使交流耦合光储发电系统可以最大化利用储能电池中的电能，无需担心停电后不能启动的问题。
附图说明
图1是本申请实施例提供的一种微电网系统；
图2是本申请实施例提供的另一种微电网系统；
图3是本申请实施例提供的再一种微电网系统。
具体实施方式
为使本申请技术方案的目的、技术方案和优点更加清楚明白，下文中将结合附图对本申请技术方案的实施例进行详细说明。需要说明的是，在不冲突的情况下，本申请中的实施例及实施例中的特征可以相互任意组合。
微电网系统，通常用于离网(与电网相分离)状态下对各类负载的持续稳定供电，当然微电网也可以有并网(与电网相连接)的场景，本申请实施例不做具体限制。微电网的供电最终来源为光伏发电，通过配置光伏发电系统，太阳能光伏板发出的直流电转变为交流电输入到电网，再通过电网向负载供电。在一些场景下，微电网还会匹配一些储能系统，当光伏发电的电量有富余的时候，由储能系统将富余的电量存储下来，在光伏发电量欠缺或者为零时，由储能系统向微电网供电，实现微电网的稳定供电。这种电力供应的相互调度，都需要由一个控制中心(如监管、管理系统)来调配，微电网的正常运行，均需要以控制中心的正常运行为基础。
本申请提供的微电网系统适用于在微电网断电后，当光照恢复后不能自动开机启动恢复微电网供电的问题，并进一步地，在启动过程中，可以准确判定开启光储设备恢复运行时机，减少盲目开机的电能消耗、或发电能力不足而启动失败。
在一些微电网中，若电网断电，整个电网中的设备均会处于缺电状态，即使光伏发电系统在恢复发电能力后，由于监管、控制系统在无外部供电的情况下无法自动恢复运行，也就无法控制光储系统为微电网正常供电。可以在电网系统断电后，当光照使得光伏发电系统恢复发电能力时，利用一个光伏发电系统建立电压，并通过继电器支路给UPS供电，在恢复监 测、控制系统上电运行，并进一步评估光伏的可用发电能力，达到预定阈值后，在控制系统的控制下，逐步恢复交流母线电压和光储系统，恢复微电网的正常运行，从而为外部负载正常供电。
在本申请提供的实施例中，光伏发电系统不仅可以在微电网正常运行的过程中给微电网供电，还可以在微电网停电后，光伏发电系统具备发电能力时，先供电给UPS，UPS再供电给系统控制器，最终在系统控制器的控制下实现微电网的自恢复、自启动。
说明书附图图1示例性地表示了本申请实施例提供的一种微电网系统。如图1所示，该系统包含了第一光伏发电系统、交流母线、UPS(Uninterrupted Power System，不间断电源)、第一开关和第二开关。
如图1所示，第一光伏发电系统，包括一个第一光伏发电单元和一个第一光伏逆变器，当然也可以有多个第一光伏发电单元和多个第一光伏逆变器，本申请实施例对此不做具体限制。第一光伏发电系统通过第一开关与UPS连接，并通过第二开关与交流母线连接。在这个系统结构中，第一光伏发电系统可以通过第一开关向UPS供电，也可以通过第二开关向交流母线供电。同时，交流母线也通过第一开关与UPS连接，当交流母线通电时，可以用于向UPS供电。UPS得到供电后便被激活进行工作，UPS通常还会配置一个蓄电池，在外部对UPS的供电不稳定的时候，UPS仍可对外输出稳定的220V交流电，如此，在UPS的供电下，微电网的其它监管、控制单元便可以正常进行工作。
进一步地，在一种可能的实施例中，第一开关包括第一触点KA1和第二触点KA2。参考图2，第一光伏发电系统通过第二触点KA2与UPS连接，交流母线通过第一触点KA1与UPS连接；当所交流母线断电时，第一触点KA1断开，第二触点KA2闭合，此时第一光伏发电系统可以向UPS供电；当交流母线通电时，第一触点KA1闭合，第二触点KA2关断，此时交流母线可以向UPS供电。本申请实施例中的第一开关，可以是普通的旋钮开关，第一触点KA1和第二触点KA2的断开或闭合可以通过手动控制的方式实现，也可以是继电器，第一触点KA1和第二触点KA2的断开或闭合通过继电器的线圈(图中未示出)带电吸附实现。当然，本领域技术人员也可以通过其它具有类似功能的开关器件实现第一触点KA1和第二触点KA2的断开或闭合，本申请实施例对第一开关的选型不作具体的限制。在UPS具备供电来源后，UPS便可以向微电网中可能的其它设备，如负责监控、管理的单元进行供电。因此，第一光伏发电系统就拥有了两个向UPS供电的路径，其中路径一为：通过第二开关项交流母线供电，从而使得交流母线可以通过第一触点KA1向UPS供电；路径二为：直接通过第二触点KA2向UPS供电。需要说明的是，在前述第一光伏发电系统向UPS直接或间接供电的前提条件是，第一光伏发电系统的可用发电功率大于或等于第一光伏供电阈值。在本申请提供的一种可能的实施例中，第一光伏发电系统中的第一光伏逆变器，可以自动检测PV(Photovoltaic)输入端的电压，当PV输入端的电压达到一定值时，可以认为第一光伏发电系统能够提供的可用发电功率达到了大于或等于第一光伏供电阈值的水平，第一光伏逆变器会自动启动运行，将PV输入端的直流电转变为交流电对外输出。第一光伏供电阈值的数值可以根据UPS对外供电的需求进行设置，本申请实施例不做具体限制。
具体地，第一光伏发电系统通过路径一还是路径二向UPS供电，取决于第二开关的通断状态。例如，如果第二开关处于断开状态，第一光伏发电系统达到供电条件时，亦即第一光伏发电系统的可用发电功率大于第一光伏供电阈值时，便会通过第二触点KA2向UPS供电；如果第二开关处于闭合状态，第一光伏发电系统达到供电条件时，亦即第一光伏发电系统的 可用发电功率大于第一光伏供电阈值时，便会通过第二开关向交流母线供电，交流母线再通过第一触点KA1向UPS供电。可选地，在开关器件的选型上，可以将第二开关设置为常开型开关，在微电网处于断电的状态下，没有系统控制器或者人为的外力将其闭合的情况下，第二开关会处于断开状态，此时，第一光伏发电系统达到供电条件时，亦即第一光伏发电系统的可用发电功率大于第一光伏供电阈值时，便会通过第二触点KA2向UPS供电；类似地，如果将第二开关设置为常闭型开关，没有系统控制器或者人为的外力将其断开的情况下，第二开关会处于闭合状态，此时，第一光伏发电系统达到供电条件时，亦即第一光伏发电系统的可用发电功率大于第一光伏供电阈值时，便会通过第二开关向交流母线供电，交流母线再通过第一触点KA1向UPS供电。当然，本领域技术人员也可以通过其它具有类似功能的开关器件设置第二开关的断开或闭合，本申请实施例对第二开关的选型不作具体的限制。
在解决微电网系统自启动前UPS的供电问题后，本申请实施例提供的另一种微电网系统中，还包括至少一个第二光伏发电系统和系统控制器。如图3所示，UPS与系统控制器连接，用于向系统控制器供电，第二光伏发电系统，包括一个第二光伏发电单元和一个第二光伏逆变器，用于向交流母线供电，当然，第二光伏发电系统中也可以有多个第二光伏发电单元和多个第二光伏逆变器，本申请实施例对此不做具体限制。系统控制器，与第一光伏供电系统、第二光伏供电系统和第二开关通信连接，可以控制第二开关的断开或闭合，并用于控制第一光伏发电系统和/或第二光伏发电系统向交流母线供电。具体地，当第二开关为常开型开关时，如果需要控制第一光伏系统和第二光伏系统一起向交流母线供电，系统控制器可以先控制第二快关闭合，然后再控制第一光伏发电系统和第二光伏发电系统一起向交流母线供电；当第二开关为常闭型开关时，第一光伏发电系统可以具备自启动的功能，第一光伏发电系统与交流母线之间是导通的状态，第一光伏发电系统在达到自启动条件的时候可以自动地直接或间接向交流母线供电，系统控制器可以继续控制第二光伏发电系统向交流母线供电，实现第一光伏发电系统和第二光伏发电系统向交流母线供电。
应当理解，第二开关的一个基本功能是在第二开关两端的任一端的电路发生故障时迅速断开，以保障另外一路不受影响，因此，在实际运用中，所有光伏发电系统都可以配置一个第二开关，本申请实施例为讨论方便，仅示例性地说明其中第一光伏供电系统对应的第二开关对微电网系统实现自启动的影响。
在一种可能的实施方式中，继续参考图3，微电网系统还可以包括至少一个储能供电系统。储能供电系统的引入，可以起到改善供电的稳定性，在储电量足够大时，可以维持光伏发电系统不具备发电条件(如夜间)下对微电网的持续供电。储能供电系统，可以有一个或多个储能单元和一个或多个储能变流器。储能单元用于存储电量，可以采用磷酸铁锂电池或铅酸电池等，本申请实施例不对电池的具体类型做具体的限制。储能变流器可以将储能单元输出的直流电转变为交流电输出给交流母线，实现储能供电系统向交流母线供电，也可以将交流母线输入的交流电转变为直流电输入给储能单元，实现交流母线向储能供电系统充电。
需要说明的是，储能供电系统进行充电或放电的前提条件是储能供电系统应当处于运行状态，运行过程会产生一定的功耗，在进行充放电之前，需要系统控制器控制交流母线向储能供电系统供电，实现对储能供电系统的唤醒，使其启动进入运行状态。
应理解，系统控制器控制交流母线向储能供电系统供电的前提条件是，第一光伏发电系统和第二光伏发电系统的可用发电功率需要大于储能供电系统自身运行的功耗，否则储能供电系统唤醒后微电网整体上会处于一个亏电的状态。因此，在实际应用中，可以设定一个第 二光伏供电阈值，当第一光伏发电系统和第二光伏发电系统的可用发电功率之和大于该第二光伏供电阈值时，就可以控制第一光伏发电系统和/或第二光伏发电系统向交流母线，交流母线向储能供电系统供电，使得储能供电系统启动进入运行状态，实现对储能供电系统的唤醒。
应理解，由于光伏发电系统的可用发电功率往往会因天气环境的变化而变化，输出的可用发电功率可能不稳定，为了改善供电，可以使用储能供电系统作为微电网的供电来源，使得利用微电网供电的负载运行地更稳定、更安全，当然，利用储能供电系统进行供电的前提是储能供电系统本身具备一定的储电量。在一种可能的实施方式中，可以给储能供电系统设定一个储能供电阈值，在储能供电系统处于运行状态时，如果储能供电系统的储电量大于或等于储能供电阈值，系统控制器可以控制储能供电系统向交流母线供电；如果储能供电系统的储电量小于储能供电阈值，可以控制交流母线向储能供电系统充电。当储能供电系统为多个时，这种控制更加灵活，储电量高的储能供电系统可以稳定地向交流母线供电，剩余储电量少的储能供电系统可以通过交流母线向其充电来提升储电量。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到的变化或替换，都应该涵盖在本申请的保护范围之内。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (10)

  1. 一种微电网系统，其特征在于：
    包括：第一光伏发电系统、交流母线、UPS(Uninterrupted Power System，不间断电源)、第一开关和第二开关；
    所述第一光伏发电系统，包括至少一个第一光伏发电单元和至少一个第一光伏逆变器，通过所述第一开关与所述UPS连接，并通过第二开关与所述交流母线连接，用于通过所述第一开关向所述UPS供电或通过所述第二开关向所述交流母线供电；
    所述交流母线，通过所述第一开关与所述UPS连接，用于通电时向所述UPS供电。
  2. 根据权利要求1所述微电网系统，其特征在于：
    所述第一开关，包括第一触点KA1和第二触点KA2；
    所述第一光伏发电系统，通过所述第二触点KA2与所述UPS连接；
    所述交流母线，通过所述第一触点KA1与所述UPS连接。
  3. 根据权利要求2所述微电网系统，其特征在于：
    所述第一触点KA1，用于当所述交流母线断电时断开，当所述交流母线通电时闭合；
    所述第二触点KA2，用于当所述交流母线断电时闭合，当所述交流母线通电时断开。
  4. 根据权利要求2或3所述微电网系统，其特征在于：
    当所述第一光伏发电系统的可用发电功率大于或等于第一光伏供电阈值时，所述第一光伏发电系统通过所述第二开关向所述交流母线供电，以使所述交流母线通过所述第一触点KA1向所述UPS供电；或者
    当所述第一光伏发电系统的可用发电功率大于或等于第一光伏供电阈值时，所述第一光伏发电系统通过所述第二触点KA2向所述UPS供电。
  5. 根据权利要4所述微电网系统，其特征在于：
    若所述第二开关处于断开状态，当所述第一光伏发电系统的可用发电功率大于第一光伏供电阈值时，所述第一光伏发电系统通过所述第二触点KA2向所述UPS供电。
  6. 根据权利要求4所述微电网系统，其特征在于：
    若所述第二开关处于闭合状态，当所述第一光伏发电系统的可用发电功率大于第一光伏供电阈值时，所述第一光伏发电系统通过所述第二开关向所述交流母线供电，以使所述交流母线通过所述第一触点KA1向所述UPS供电。
  7. 根据权利要求1-6任一项所述微电网系统，其特征在于：
    还包括：至少一个第二光伏发电系统和系统控制器；
    所述UPS与所述系统控制器连接，用于向所述系统控制器供电；
    每个所述第二光伏发电系统，包括至少一个第二光伏发电单元和至少一个第二光伏逆变器，用于向所述交流母线供电；
    所述系统控制器，用于控制所述第二开关的闭合或断开，并用于控制所述第一光伏发电系统和/或所述第二光伏发电系统向所述交流母线供电。
  8. 根据权利要求1-7任一项所述微电网系统，其特征在于：
    还包括至少一个储能供电系统；
    所述储能供电系统，包括至少一个储能单元和至少一个储能变流器，用于向所述交流母线供电或者接受所述交流母线的供电；
    所述系统控制器，还用于控制所述储能供电系统向所述交流母线供电，或者，用于控制所述交流母线向所述储能供电系统供电，以使所述储能供电系统启动至运行状态。
  9. 根据权利要求8所述微电网系统，其特征在于：
    所述系统控制器用于：
    当所述第一光伏发电系统和所述第二光伏发电系统的可用发电功率之和大于第二光伏供电阈值时，控制所述第一光伏发电系统和/或所述第二光伏发电系统向所述交流母线供电，并控制所述交流母线向所述储能供电系统供电，以使所述储能供电系统启动至运行状态。
  10. 根据权利要求8或9所述微电网系统，其特征在于：
    所述系统控制器用于：
    当所述储能供电系统处于运行状态时，若所述储能供电系统的储电量大于或等于储能供电阈值时，控制所述储能供电系统向所述交流母线供电；或者
    当所述储能供电系统处于运行状态时，若所述储能供电系统的储电量小于储能供电阈值时，控制所述交流母线向所述储能供电系统充电。
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