WO2022213338A1 - 一种储能系统、储能系统的控制方法及光伏发电系统 - Google Patents

一种储能系统、储能系统的控制方法及光伏发电系统 Download PDF

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Publication number
WO2022213338A1
WO2022213338A1 PCT/CN2021/086070 CN2021086070W WO2022213338A1 WO 2022213338 A1 WO2022213338 A1 WO 2022213338A1 CN 2021086070 W CN2021086070 W CN 2021086070W WO 2022213338 A1 WO2022213338 A1 WO 2022213338A1
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WO
WIPO (PCT)
Prior art keywords
battery
battery pack
parameter value
energy storage
cluster
Prior art date
Application number
PCT/CN2021/086070
Other languages
English (en)
French (fr)
Inventor
李琳
吴志鹏
於波
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华为数字能源技术有限公司
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 华为数字能源技术有限公司 filed Critical 华为数字能源技术有限公司
Priority to EP21935567.4A priority Critical patent/EP4304042A1/en
Priority to KR1020237036177A priority patent/KR20230160873A/ko
Priority to JP2023561682A priority patent/JP2024513477A/ja
Priority to AU2021439922A priority patent/AU2021439922A1/en
Priority to CN202180065807.1A priority patent/CN116615829A/zh
Priority to PCT/CN2021/086070 priority patent/WO2022213338A1/zh
Publication of WO2022213338A1 publication Critical patent/WO2022213338A1/zh
Priority to US18/477,029 priority patent/US20240030724A1/en

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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
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014—Circuits for equalisation of charge between batteries
    • H02J7/0016—Circuits for equalisation of charge between batteries using shunting, discharge or bypass circuits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H01M10/441—Methods for charging or discharging for several batteries or cells simultaneously or sequentially
    • 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
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
    • 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
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
    • H02J7/0048—Detection of remaining charge capacity or state of charge [SOC]
    • 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
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
    • H02J7/005—Detection of state of health [SOH]
    • 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
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • 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
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/007188—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters
    • 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
    • H02J7/00—Circuit arrangements for charging or depolarising 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—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J2207/20—Charging or discharging characterised by the power electronics converter
    • 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
    • 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
    • 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
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • 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
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/12—Monitoring or controlling equipment for energy generation units, e.g. distributed energy generation [DER] or load-side generation
    • Y04S10/123—Monitoring or controlling equipment for energy generation units, e.g. distributed energy generation [DER] or load-side generation the energy generation units being or involving renewable energy sources
    • 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
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/14—Energy storage units

Definitions

  • the present application relates to the technical field of power supplies, and in particular, to an energy storage system, a control method of the energy storage system, and a photovoltaic power generation system.
  • Adding an energy storage system using electrochemical batteries on the power generation side can store excess power that cannot be consumed during periods of high power generation or low power consumption, and release it during low power generation or peak power consumption to stabilize power generation. Reduce the impact on the AC power grid.
  • the energy storage system using electrochemical cells generally connects multiple battery packs in series to form a high-voltage, large-capacity battery cluster.
  • Each battery pack includes a plurality of battery cells connected in series or mixed. Due to the difference in the state of health (SOH) or the original state of charge (SOC) of the battery, the power of each battery pack is unbalanced, resulting in differences in the time it takes for each battery pack to be fully charged or discharged. .
  • SOH state of health
  • SOC original state of charge
  • the present application provides an energy storage system, a control method for the energy storage system, and a photovoltaic power generation system, which can balance the power of each battery pack, reduce the impact on the battery cluster current, and further reduce the waste of power.
  • the present application provides an energy storage system.
  • the energy storage system is applied in the scenario of new energy power generation.
  • the output end of the energy storage system is connected to the AC power grid, which can store energy that cannot be consumed during periods of high power generation or low power consumption. The excess electrical energy is stored and released during low power generation or peak power consumption periods to reduce the impact on the AC grid.
  • the energy storage system includes battery clusters, power conversion circuits and controllers. The output end of the battery cluster is connected to the first end of the power conversion circuit, and the second end of the power conversion circuit is connected to the output end of the energy storage system.
  • the power conversion circuit is used to convert the DC power provided by the battery cluster into AC power and then transmit it to the AC power grid, or convert the AC power obtained from the second end of the power conversion circuit into DC power and then charge the battery cluster.
  • the alternating current can be provided by the alternating current grid, or by the new energy power generation equipment.
  • Each battery cluster includes at least two energy storage modules connected in series, each energy storage module includes a bypass circuit and a battery pack, each battery pack includes multiple batteries, and the multiple batteries in the battery pack can be Connect in series or mix.
  • the controller controls each bypass circuit according to the first parameter value of each battery pack, so as to balance the power of each battery pack.
  • each battery pack in the battery cluster is connected to a bypass circuit correspondingly, and the controller controls each bypass circuit according to the first parameter value of each battery pack, so that the battery pack can be transferred from the battery pack to the battery cluster.
  • middle bypass When the battery cluster is charged, the bypassed battery packs stop charging first, and as the battery packs are gradually bypassed, the power levels of the battery packs in the battery cluster are synchronized. When the battery cluster is discharged, the bypassed battery packs stop discharging first, and as the battery packs are gradually bypassed, the power levels of the battery packs in the battery cluster are also synchronized.
  • the energy storage system can balance the power of each battery pack, reduce the impact on the battery cluster current, and thus reduce the waste of power.
  • the maximum backup time is also achieved.
  • the controller may be an Application Specific Integrated Circuit (ASIC), a Programmable Logic Device (PLD), a Digital Signal Processor (DSP) or a combination thereof.
  • ASIC Application Specific Integrated Circuit
  • PLD Programmable Logic Device
  • DSP Digital Signal Processor
  • the above-mentioned PLD can be a complex programmable logic device (Complex Programmable Logic Device, CPLD), a field-programmable gate array (Field-programmable Gate Array, FPGA), a general array logic (Generic Array Logic, GAL) or any combination thereof.
  • the controller can be a one-stage controller, or a multi-stage controller.
  • the controller is a multi-level controller
  • the upper-level controller can control the lower-level controller, and there can be multiple lower-level controllers.
  • the multi-level controller can be integrated on a printed circuit board (Printed circuit board, PCB), or physically divided into multiple parts and arranged on the PCB in different positions of the energy storage system, and each part cooperates to realize the control function. .
  • PCB printed circuit board
  • the controller is specifically configured to control each bypass circuit to bypass the battery pack whose first parameter value is greater than or equal to the first preset parameter value when the battery cluster is charged, and the remaining battery packs Continue charging; and when the battery cluster is discharged, control each bypass circuit to bypass the battery packs whose first parameter value is less than or equal to the second preset parameter value, and the remaining battery packs continue to discharge.
  • the remaining battery packs can still be charged or discharged at the maximum current, so the current of the battery cluster can remain unchanged.
  • the bypass circuit includes a first controllable switch and a second controllable switch.
  • the positive output end of the battery pack is connected to the first end of the first controllable switch
  • the second end of the first controllable switch is connected to the first end of the second controllable switch and the positive output end of the energy storage module
  • the second controllable switch is connected to the first end of the second controllable switch and the positive output end of the energy storage module.
  • the second end of the switch is connected to the negative output end of the battery module
  • the negative output end of the battery pack is connected to the negative output end of the energy storage module.
  • the controller is specifically configured to first control both the first controllable switch and the second controllable switch to be turned off, and then control the second controllable switch to be turned on after a first preset time, so as to bypass the battery Bag.
  • the first preset time is greater than or equal to the dead time of the first controllable switch, so as to avoid the first controllable switch and the second controllable switch Simultaneous closure results in a short circuit between the positive and negative outputs of the battery pack.
  • the controller is specifically configured to sequentially bypass the battery packs whose first parameter value is greater than or equal to the first preset parameter value when the battery cluster is charged, until only one battery pack remains unbypassed , indicating that the battery cluster is fully charged at this time, and the only remaining battery packs are no longer bypassed; and when the battery cluster is discharged, the battery packs whose first parameter value is less than or equal to the second preset parameter value are bypassed in turn, until only the remaining battery packs are left. If a battery pack is not bypassed, it means that the battery cluster is discharged at this time, and the only remaining battery pack is no longer bypassed.
  • the controller is further configured to control each bypass circuit to make the bypass circuit when the first parameter value of only one remaining battery pack is greater than or equal to the first preset parameter value when the battery cluster is charged.
  • the battery pack of the circuit is reconnected to the battery cluster, and when the battery cluster is discharged and the first parameter value of only one remaining battery pack is less than or equal to the second preset parameter value, each bypass circuit is controlled to make the bypassed battery The package is reconnected to the battery cluster.
  • the controller is specifically configured to first control both the first controllable switch and the second controllable switch to be turned off, and then control the first controllable switch to be turned on after a second preset time, so that the battery pack is closed. Reconnect the battery cluster.
  • the second preset time is greater than or equal to the dead time of the second controllable switch, so as to avoid the first controllable switch and the second controllable switch Simultaneous closure results in a short circuit between the positive and negative outputs of the battery pack.
  • the power conversion circuit includes a DC/DC conversion circuit and a DC/AC conversion circuit.
  • the first end of the DC/DC conversion circuit is the first end of the power conversion circuit
  • the second end of the DC/DC conversion circuit is connected to the first end of the DC/AC conversion circuit
  • the second end of the DC/AC conversion circuit is the power conversion circuit the second end of the circuit.
  • the DC/DC conversion circuit is used to convert the DC power provided by the battery cluster to the DC/AC conversion circuit, or convert the DC power provided by the DC/AC conversion circuit to the battery cluster after DC conversion.
  • the DC/AC conversion circuit is used to convert the DC power provided by the DC/DC conversion circuit into AC power, or convert the obtained AC power into DC power and transmit it to the DC/DC conversion circuit.
  • the controller is also used to control the DC/DC conversion circuit to stop working before the battery pack is bypassed or connected to the battery pack.
  • the energy storage system further includes a slow-start circuit
  • the positive port of the output end of the battery cluster is connected to the positive port of the first end of the DC/DC conversion circuit through the slow-start circuit, or the negative port of the output end of the battery cluster is connected
  • the port is connected to the negative port of the first end of the DC/DC conversion circuit through a slow-start circuit.
  • the slow start circuit includes: a first relay, a second relay and a first resistor. Wherein, the first relay is connected in series with the first resistor and then connected in parallel with the second relay.
  • the controller is also used for controlling the first relay and the second relay to disconnect before bypassing the battery pack or connecting the battery pack.
  • the controller is further configured to control the voltage of the first terminal of the DC/DC conversion circuit to be equal to the output voltage of the battery cluster after the bypass or access to the battery pack is completed, and then control the second The relay is closed.
  • the first end of the DC/DC conversion circuit is generally provided with a bus capacitor.
  • the controller controls the voltage at the first end of the DC/DC conversion circuit to be equal to the output voltage of the battery cluster, so that the voltage of the bus capacitor is equal to the output voltage of the battery cluster, and then controls The second relay is closed. At this time, the voltage of the bus capacitor will not cause an impact on the battery cluster, thus protecting the battery cluster.
  • the controller is further configured to control the first relay to be closed and the second relay to be disconnected after the bypass or access to the battery pack is completed, and to control the first relay after a third preset time. open and the second relay is closed.
  • the first terminal of the DC/DC conversion circuit and the output terminal of the battery cluster are charged and discharged after the current is limited by the first relay and the first resistor to achieve potential equalization, which reduces the impact on the battery. Cluster shock.
  • the controller includes a first controller and at least two second controllers.
  • the second controller is connected with the battery pack in one-to-one correspondence.
  • the second controller is configured to acquire the second parameter value of the corresponding battery pack, and send the second parameter value to the first controller.
  • the first controller is configured to use the second parameter values of all battery packs to determine the first parameter values of all battery packs, and when the battery cluster is charged, determine that the battery packs with the first parameter value greater than or equal to the first preset parameter value are to be Bypass the battery pack, and when the battery cluster is discharged, determine the battery pack with the first parameter value less than or equal to the second preset parameter value as the battery pack to be bypassed, and then send a control instruction to the second controller.
  • the control instruction is used to instruct the corresponding second controller to control the bypass circuit to bypass the battery pack to be bypassed.
  • the second controller is a battery electronic control unit (Battery Monitoring Unit, BMU), and the first controller is a battery control unit (Battery Control Unit, BCU).
  • BMU Battery Monitoring Unit
  • BCU Battery Control Unit
  • the second parameter value includes a total capacity of the battery pack, an energy state SOE value, and a state of health SOH value
  • the first parameter value is a state-of-charge SOC value.
  • the controller includes a first controller and at least two second controllers.
  • the second controller is connected with the battery pack in one-to-one correspondence.
  • the second controller acquires the first parameter value of the corresponding battery pack, and sends the first parameter value to the first controller.
  • the first controller determines that the battery pack with the first parameter value greater than or equal to the first preset parameter value is the battery pack to be bypassed, and when the battery cluster is discharged, determines that the first parameter value is less than or equal to the first parameter value.
  • the battery pack with the two preset parameter values is the battery pack to be bypassed, and then a control command is sent to the second controller.
  • the control instruction is used to instruct the corresponding second controller to control the bypass circuit to bypass the battery pack to be bypassed.
  • the first parameter value is a voltage value or a state-of-charge SOC value.
  • the present application also provides a control method for an energy storage system.
  • the method is applied to the energy storage system provided by the above implementation manner, and the method includes:
  • each bypass circuit is controlled to balance the power of each battery pack.
  • the power of each battery pack can be balanced.
  • the bypass circuit can be controlled to bypass the battery pack where the abnormal battery is located, so as to remove the fault and ensure that the remaining battery packs can continue to operate normally.
  • each bypass circuit is controlled according to the first parameter value of each battery pack, which specifically includes:
  • each bypass circuit is controlled to bypass the battery pack whose first parameter value is less than or equal to the second preset parameter value.
  • controlling each bypass circuit to bypass the battery pack whose first parameter value is greater than or equal to the first preset parameter value specifically includes:
  • control each bypass circuit to bypass the battery pack whose first parameter value is less than or equal to the second preset parameter value, specifically including:
  • the battery packs whose first parameter value is less than or equal to the second preset parameter value are bypassed in sequence until only one battery pack remains unbypassed.
  • the method further includes:
  • each bypass circuit is controlled to reconnect the bypassed battery pack to the battery cluster.
  • the method further includes:
  • control the DC/DC conversion circuit connected to the output end of the battery cluster Before bypassing the battery pack or connecting to the battery pack, control the DC/DC conversion circuit connected to the output end of the battery cluster to stop working, and the first end of the DC/DC conversion circuit is connected to the output end of the battery cluster;
  • the voltage of the first terminal of the DC/DC conversion circuit is controlled to be equal to the output voltage of the battery cluster, and then the DC/DC conversion circuit is controlled to start working.
  • the method further includes:
  • the first parameter values of all the battery packs are determined.
  • the second parameter value includes a total capacity of the battery pack, an energy state SOE value, and a state of health SOH value
  • the first parameter value is a state-of-charge SOC value.
  • the first parameter value is a voltage value or a state-of-charge SOC value.
  • the present application further provides a photovoltaic power generation system
  • the photovoltaic power generation system includes the energy storage system provided by the above implementation manner, and also includes a photovoltaic power generation terminal.
  • the output end of the photovoltaic power generation end is used to connect to the AC power grid.
  • the photovoltaic power generation terminal is used to generate alternating current by utilizing light energy.
  • the alternating current can be transmitted to the alternating current grid, or through the power conversion circuit of the energy storage system to charge the battery cluster.
  • the present application further provides a photovoltaic power generation system, where the photovoltaic power generation system includes the energy storage system provided by the above implementation manner, and further includes components. Photovoltaic modules are used to use light energy to generate direct current to charge battery clusters.
  • a bypass circuit is correspondingly connected to each battery pack in the battery cluster of the photovoltaic power generation system provided by the present application, and the controller controls each bypass circuit according to the first parameter value of each battery pack, so as to connect the battery pack from the battery cluster to the bypass circuit. middle bypass.
  • the bypassed battery packs stop charging first, and as the battery packs are gradually bypassed, the power levels of the battery packs in the battery cluster are synchronized.
  • the bypassed battery pack stops discharging first, and as the battery pack is gradually bypassed, the power of each battery pack in the battery cluster is also synchronized.
  • the photovoltaic power generation system can balance the power of each battery pack, reduce the impact on the current of the battery cluster, and thus reduce the waste of power.
  • the maximum backup time is also achieved.
  • FIG. 1 is a schematic new energy power generation system provided by an embodiment of the present application
  • FIG. 2 is a schematic diagram of an energy storage system provided by an embodiment of the present application.
  • FIG. 3 is a schematic diagram of a battery cluster provided by an embodiment of the present application.
  • FIG. 4 is a schematic diagram of another battery cluster provided by an embodiment of the present application.
  • FIG. 5 is a schematic diagram of another energy storage system provided by an embodiment of the present application.
  • FIG. 6 is a schematic diagram of yet another energy storage system provided by an embodiment of the present application.
  • FIG. 7 is a flowchart of a method for judging the charging and discharging state of a battery pack provided by an embodiment of the present application
  • FIG. 8 is a schematic diagram of a control method of an energy storage system provided by an embodiment of the present application.
  • FIG. 9 is a schematic diagram of another control method of an energy storage system provided by an embodiment of the present application.
  • FIG. 10 is a schematic diagram of another control method of an energy storage system provided by an embodiment of the present application.
  • FIG. 11 is a schematic diagram of a photovoltaic power generation system provided by an embodiment of the application.
  • FIG. 12 is a schematic diagram of another photovoltaic power generation system provided by an embodiment of the present application.
  • FIG. 1 this figure is a schematic new energy power generation system provided by an embodiment of the present application.
  • the new energy power generation system includes a battery cluster 10 , a power conversion circuit 20 , a new energy power generation terminal 30 and a load 40 .
  • the new energy power generation terminal 30 is used for outputting alternating current. Since the new energy power generation terminal 30 has the characteristics of volatility and uncertainty, its power generation volume fluctuates.
  • the alternating current output from the new energy generating end 30 is higher than the electricity demand of the alternating current grid 50 , the excess electricity is converted into direct current by the power conversion circuit 20 and then charges the battery cluster 10 .
  • the power conversion circuit 20 converts the direct current output from the battery cluster 10 into alternating current and outputs it to the alternating current grid 50 to stabilize the alternating current grid 50.
  • the new energy power generation terminal 30 includes a photovoltaic module and a direct current (DC)/alternating current (AC) conversion circuit (which may also be called an inverter circuit or inverter).
  • the photovoltaic module utilizes light energy to generate direct current
  • the DC/AC conversion circuit converts the direct current into alternating current and outputs it to the alternating current grid 50 and/or charges the battery cluster 10 .
  • the load 40 is the electrical equipment of the new energy power generation system, which is not specifically limited in this application.
  • the battery cluster 10 includes a plurality of battery packs, and each battery pack includes a plurality of battery cells connected in series or mixed. Due to the different SOH or original SOC of each battery, the power of each battery pack is unbalanced, resulting in differences in the time it takes for each battery pack to be fully charged or discharged. Specifically, when multiple battery packs are connected in series to form a battery cluster, since all battery packs have the same current, it is necessary to limit the total current of the battery cluster according to the minimum battery pack current, which will result in batteries with more remaining power. The battery pack cannot be fully discharged, and the battery pack with less remaining power cannot be fully charged, so the power of the battery pack cannot be fully utilized, which limits the current of the battery cluster and causes a waste of power. When charging or discharging next time, the battery cluster cannot achieve the maximum backup time due to the unbalanced power of each battery pack.
  • the present application provides an energy storage system, a control method for the energy storage system, and a photovoltaic power generation system.
  • the battery packs in the battery cluster of the energy storage system are all connected with a bypass circuit, and the controller is based on The first parameter value of each battery pack controls each bypass circuit, so that the battery pack can be bypassed from the battery cluster, so as to balance the power of each battery pack.
  • the remaining battery packs can still be charged or discharged at the maximum current, so the current of the battery cluster can remain unchanged.
  • Using the energy storage system can balance the power of each battery pack, reduce the impact on the current of the battery cluster, thereby reduce the waste of power, and achieve the maximum backup time.
  • connection should be understood in a broad sense.
  • connection may be a fixed connection, a detachable connection, or an integral body; it may be a direct connection, or a Indirect connections can be made through an intermediary.
  • FIG. 2 is a schematic diagram of an energy storage system provided by an embodiment of the application
  • FIG. 3 is a schematic diagram of a battery cluster provided by an embodiment of the application.
  • the energy storage system includes a battery cluster 10 , a power conversion circuit 20 and a controller 100 .
  • the output end of the battery cluster 10 is connected to the first end of the power conversion circuit 20, and the second end of the power conversion circuit 20 is connected to the output end of the energy storage system for outputting electric energy for the AC grid.
  • each battery 10 includes at least two energy storage modules connected in series.
  • the energy storage module is represented by 10a 1 -10am .
  • the energy storage module 10a 1 includes a bypass circuit 101b 1 and a battery pack 101a 1 .
  • each battery in the battery pack may be connected in series or in a mixed manner, which is not specifically limited in the embodiment of the present application.
  • each battery in the battery pack is connected in series as an example.
  • the bypass circuit in the embodiment of the present application includes two working states. Among them, in the first working state, the corresponding battery pack is not bypassed, so that the corresponding battery pack can be connected to the battery cluster in series; in the second working state, the corresponding battery pack is bypassed, that is, the battery pack It is equivalent to being cut off from the battery cluster. Specifically, when the battery cluster is in the charging state, the battery pack is bypassed and then stops charging, and when the battery cluster is in the discharging state, the battery pack is bypassed and stops discharging.
  • the first parameter value can represent the power state of the battery pack
  • the controller 100 can determine the power level of the corresponding battery pack according to the first parameter value, and switch between the above two working states by controlling the bypass circuit, so that the power of each battery pack is Power balance.
  • the above controller can be a dedicated ASIC, PLD, DSP, or a combination thereof.
  • the foregoing PLD may be a CPLD, an FPGA, a GAL, or any combination thereof, which is not specifically limited in this embodiment of the present application.
  • the controller in the above description of the embodiments of the present application may be a one-level controller or a multi-level controller.
  • the upper-level controller can accept the information sent by the lower-level controller, the number of lower-level controllers can be multiple, and the upper-level controller can control the lower-level controllers.
  • the multi-level controller can be independently integrated on the printed circuit board (PCB), or it can be physically divided into multiple parts and arranged on the PCB at different positions of the energy storage system, and each part cooperates to realize the control function. , which is not specifically limited in the embodiments of the present application.
  • the battery cells in the battery pack may be lithium-ion batteries, lead-acid batteries, super capacitors, etc., or a combination of the above types, which are not specifically limited in the embodiments of the present application.
  • the bypassed battery packs stop charging first, and as the battery packs are gradually bypassed, the power levels of the battery packs in the battery cluster are synchronized.
  • the bypassed battery packs stop discharging first, and as the battery packs are gradually bypassed, the power levels of the battery packs in the battery cluster are also synchronized.
  • the remaining battery packs can still be charged or discharged at the maximum current, so the current of the battery cluster can remain unchanged.
  • the energy storage system can balance the power of each battery pack, reduce the impact on the battery cluster current, and thus reduce the waste of power.
  • the maximum backup time is also achieved.
  • FIG. 4 this figure is a schematic diagram of another battery cluster provided by the embodiment of the present application.
  • the illustrated controller includes two stages of controllers: a first stage controller 1001 and a second stage controller 1002a1-1002am.
  • the number of the second-level controllers is consistent with the number of battery packs, and the second-level controllers are connected to the battery packs in one-to-one correspondence.
  • Each second controller is connected to the first controller 1001 , and communication between each second controller and the first controller 1001 is possible.
  • the first controllable switch is S11
  • the second controllable switch is S12.
  • the positive output end of the battery pack 101a1 is connected to the first end of the first controllable switch S11
  • the second end of the first controllable switch S11 is connected to the first end of the second controllable switch S12 and the positive output end of the energy storage module 10a1
  • the second end of the second controllable switch S12 is connected to the negative output end of the battery module 10a2, and the negative output end of the battery pack 101a1 is connected to the negative output end of the energy storage module 10a1.
  • S21 and S22 correspond to the battery module 101a 2
  • Sm1 and Sm2 correspond to the battery module 101a m .
  • the first controllable switch and the second controllable switch in each battery module can be an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT), a metal oxide semiconductor field effect transistor (Metal Oxide Semiconductor Field effect transistor (Metal Oxide Semiconductor Field effect transistor, MOSFET, MOSFET). ), silicon carbide field effect transistor (Silicon Carbide Metal Oxide Semiconductor, SiC MOSFET), mechanical switch or a combination of the above.
  • the second controller controls the working state of the first controllable switch and the second controllable switch by sending a control signal to the first controllable switch and the second controllable switch.
  • the control signal is a pulse width modulation (Pulse width modulation, PWM). Signal.
  • the first end of the first controllable switch and the second controllable switch is the drain, and the second end is the gate.
  • the direction of the body diode of S11 is opposite to the direction of the battery voltage
  • the direction of the body diode of S12 is opposite to the direction of the body diode of S11, thereby preventing the battery module from being directly short-circuited through the body diode.
  • the body diode of the switching device may also be replaced with an additional parallel diode.
  • the above switching device may be disposed inside the battery module, or the second controller may be integrated together, or be independently designed on the PCB and then integrated inside or outside the battery pack, which is not specifically limited in this embodiment of the present application.
  • the second controller is a battery electronic control unit
  • the first controller is a battery control unit
  • the controller is specifically configured to control each bypass circuit to bypass a battery pack whose first parameter value is greater than or equal to the first preset parameter value when the battery cluster is charged, and to control each bypass circuit when the battery cluster is discharged
  • the working principle of the controller will be specifically described below.
  • the following first describes an implementation manner of the first control bypass circuit.
  • Each second controller acquires the second parameter value of the corresponding battery pack, and sends the second parameter value to the first controller.
  • the second parameter value includes the total capacity Q of the battery pack, a state of energy (State of Energy, SOE) value, and a state of health (State of Health, SOH) value.
  • the SOE value represents the current controllable power of the battery pack.
  • SOH characterizes the ability of the current battery pack to store electrical energy relative to the new battery pack, and it can be understood as the ratio of the current available capacity to the total capacity Q in the form of a percentage.
  • the first controller uses the acquired second parameter values of all battery packs to determine first parameter values corresponding to all batteries, and when the battery cluster is charged, determines that the battery packs with the first parameter value greater than or equal to the first preset parameter value are: The battery pack to be bypassed, and when the battery cluster is discharged, it is determined that the battery pack with the first parameter value less than or equal to the second preset parameter value is the battery pack to be bypassed.
  • the first parameter value is a state of charge (State of Charge, SOC) value.
  • SOC state of Charge
  • the first preset parameter value and the second preset parameter value are preset according to the actual situation and stored in the first controller, and are called when they are to be used.
  • the first preset parameter value and the second preset parameter value are The parameter value is not specifically limited.
  • the first controller can determine the SOC value by the following formula:
  • the SOC obtained in formula (1) is the current actual SOC of the battery pack, that is, the ratio of the current power to the current capacity.
  • control instruction sent by the first controller is used to instruct the second controller 1002a1 to control S11 and S12 so that the battery pack 101a1 is bypassed.
  • the first controllable switch S11 When the battery pack 101a1 is normally connected to the battery cluster in series, the first controllable switch S11 is closed, and the second controllable switch S12 is opened.
  • the second controller 1002a1 bypasses the battery pack 101a1, the first controllable switch S11 and the second controllable switch S12 are both turned off, and the second controllable switch S12 is turned on after a first preset time.
  • the first preset time is greater than or equal to the dead time of the first controllable switch S11, so as to prevent the first controllable switch S11 and the second controllable switch S12 from being closed at the same time, causing the positive output terminal of the battery pack 101a1 and the battery pack 101a1 to be closed at the same time.
  • the negative output terminals are short-circuited, and the embodiment of the present application does not specifically limit the first preset time.
  • the first controller sequentially determines the battery pack whose first parameter value is greater than or equal to the first preset parameter value as the battery pack to be bypassed, and sends a control instruction to the second controller, so that the second controller controls each bypass circuit
  • the battery packs to be bypassed are bypassed in sequence until only one battery pack remains unbypassed, at which point the remaining bypassed battery packs have achieved power balance.
  • the first controller determines that the first parameter value of the only remaining battery pack is greater than or equal to the first preset parameter value, it means that the battery cluster is fully charged at this time, and no bypass is required. Only the remaining battery packs are controlled by the second controller to reconnect to the battery cluster all bypassed battery packs.
  • the first controller sequentially determines that the battery pack whose first parameter value is less than or equal to the second preset parameter value is the battery pack to be bypassed, and sends a control instruction to the second controller, so that the second controller controls each bypass circuit
  • the battery packs to be bypassed are bypassed in sequence until only one battery pack remains unbypassed, at which point the remaining bypassed battery packs have achieved power balance.
  • Only one remaining battery pack continues to discharge.
  • the first controller determines that the first parameter value of the only remaining battery pack is less than or equal to the second preset parameter value, it indicates that the battery cluster is discharged at this time, and the battery pack is no longer bypassed.
  • the remaining battery packs are controlled by the second controller to reconnect to the battery cluster.
  • the controller controls the battery pack 101a1 to reconnect to the circuit, it first controls both the first controllable switch S11 and the second controllable switch S12 to turn off, and then controls the first controllable switch to turn on S11 after a second preset time.
  • the second preset time is greater than or equal to the dead time of the second controllable switch S12, so as to prevent the first controllable switch S11 and the second controllable switch S12 from being closed at the same time and causing the positive and negative output terminals of the battery pack 101a1
  • the second preset time is not specifically limited in this embodiment of the present application.
  • Each second controller is configured to acquire the first parameter value of the corresponding battery pack, and send the first parameter value to the first controller 1001 .
  • the first parameter value is a voltage value or an SOC value.
  • the first controller determines that the battery pack with the first parameter value greater than or equal to the first preset parameter value is the battery pack to be bypassed, and when the battery cluster is discharged, determines that the first parameter value is less than or equal to the first parameter value.
  • the battery pack with the two preset parameter values is the battery pack to be bypassed.
  • the first controller 1001 sends a control instruction to each second controller.
  • the control instruction is used to instruct the corresponding second controller to control the bypass circuit to bypass the battery pack to be bypassed, which will be described in detail below.
  • the first preset parameter value is a first preset voltage value
  • the second preset parameter value is a second preset voltage value.
  • the first controller sequentially determines that the battery pack whose voltage value is greater than or equal to the first preset voltage value is the battery pack to be bypassed, and sends a control instruction to the second controller, so that the second controller controls each bypass circuit to bypass the bypass circuit in turn.
  • Each battery pack is to be bypassed until only one battery pack remains unbypassed, at which point the remaining bypassed battery packs have achieved power balance and completed charging.
  • the first controller determines that the voltage value of the only remaining battery pack is greater than or equal to the first preset voltage value, it means that the battery cluster is fully charged at this time, and the battery pack is no longer bypassed.
  • the remaining battery packs are controlled by the second controller to reconnect to the battery cluster.
  • the power of each battery pack may be unbalanced, so that the discharge time of each battery pack may be different, so the voltage of each battery pack is different.
  • the first controller sequentially determines that the battery pack whose voltage value is less than or equal to the second preset voltage value is the battery pack to be bypassed, and sends a control instruction to the second controller, so that the second controller controls each bypass circuit to bypass the bypass circuit in turn.
  • Each battery pack is to be bypassed until only one battery pack remains unbypassed. At this time, the remaining bypassed battery packs have achieved power balance and completed discharge.
  • the first controller determines that the voltage value of the only remaining battery pack is less than or equal to the second preset voltage value, it indicates that the battery cluster is discharged at this time, and the only remaining battery pack is no longer bypassed. battery packs, and all bypassed battery packs are controlled to be reconnected to the battery cluster through the second controller.
  • the controller controls the bypass circuit, so that the battery pack is bypassed or reconnected to the battery cluster in series in the same manner as described above, and will not be repeated here.
  • the first parameter value is the voltage value as an example.
  • the first preset parameter value is the first preset SOC value
  • the second preset parameter value is the second preset SOC value. value.
  • the specific working process of the controller is similar to the above description, and is not repeated here in this embodiment.
  • the energy storage system can balance the power of each battery pack.
  • the fully charged or discharged battery pack is removed, other battery packs can still be charged or discharged with the maximum current, reducing the need for energy consumption.
  • the effect of battery cluster current due to the equalization of the power of each battery pack, the maximum backup time is also achieved.
  • the bypass circuit can be controlled to bypass the battery pack where the abnormal battery is located, so as to remove the fault and ensure that the remaining battery packs can continue to operate normally.
  • the controller in the embodiment of the present application may also control the working state of the power conversion circuit, which will be described in detail below with reference to the accompanying drawings.
  • FIG. 5 this figure is a schematic diagram of another energy storage system provided by an embodiment of the present application.
  • the power conversion circuit 20 of the energy storage system includes a DC/DC conversion circuit 201 and a DC/AC conversion circuit 202 .
  • the first end of the DC/DC conversion circuit 201 is the first end of the power conversion circuit 20
  • the second end of the DC/DC conversion circuit 201 is connected to the first end of the DC/AC conversion circuit 202
  • the DC/AC conversion circuit 202 The second end of is the second end of the power conversion circuit 201 .
  • the DC/DC conversion circuit 201 is used to convert the DC power provided by the battery cluster 10 to DC and then transmit it to the DC/AC conversion circuit 202, or convert the DC power provided by the DC/AC conversion circuit 202 to DC and then transmit it to the battery cluster 10, Furthermore, the battery cluster 10 is charged.
  • the DC/AC conversion circuit 202 is used to convert the DC power provided by the DC/DC conversion circuit 201 into AC power, or convert the obtained AC power into DC power and transmit it to the DC/DC conversion circuit 201.
  • the second terminal of the DC/AC conversion circuit 202 AC power can be obtained from the AC power grid or the new energy power generation terminal.
  • the DC/AC conversion circuit 202 is a bidirectional DC/AC converter, and a neutral point clamped T-type three-level circuit, a neutral point clamped (NPC) circuit, Active Neutral Point Clamped (Active Neutral Point Clamped, ANPC) circuit, flying capacitor multi-level circuit, etc. Since the port voltage of the single battery changes with the energy storage capacity, the port output voltage of the battery cluster is a wide Therefore, in order to match the voltage variation range of the battery cluster port, the DC/DC conversion circuit 201 and the DC/AC conversion circuit 202 usually support a wide range of input and output capabilities.
  • on-line bypass or on-line access can be performed, and at this time, the DC/DC conversion circuit 201 operates normally.
  • the controller 100 is further configured to control the DC/DC conversion circuit 201 to stop working before bypassing or connecting the battery pack, and then control the DC/DC conversion circuit 201 after the battery pack is bypassed or connected.
  • the conversion circuit 201 resumes operation.
  • the DC/DC conversion circuit 201 stops working, that is, controls the DC/DC conversion circuit 201 to shut down, or stops sending control signals to the DC/DC conversion circuit 201 .
  • FIG. 6 this figure is a schematic diagram of yet another energy storage system provided by an embodiment of the present application.
  • the energy storage system shown in the figure also includes a slow-start circuit 60.
  • the positive port of the output end of the battery cluster 10 is connected to the positive port of the first end of the DC/DC conversion circuit 201 through the slow-start circuit 60, or the negative port of the output end of the battery cluster 10 is connected through the slow-start circuit 60.
  • the slow-start circuit 60 is connected to the negative port of the first end of the DC/DC conversion circuit 201 .
  • FIG. 6 shows an implementation when the slow-start circuit 60 is connected to the positive port of the first end of the DC/DC conversion circuit 201 .
  • the slow start circuit 60 specifically includes: a first relay K1, a second relay K2 and a first resistor R1.
  • the first relay K1 is connected in series with the first resistor R1 and then connected in parallel with the second relay K2.
  • the controller 100 is further configured to control the first relay and the second relay to disconnect before bypassing the battery pack or connecting the battery pack, so that the DC/DC conversion circuit 201 stops working.
  • the controller 100 is further configured to control the voltage of the first terminal of the DC/DC conversion circuit 201 to be equal to the battery cluster after the bypass or access to the battery pack is completed. 10 output voltage, and then control the second relay K2 to close.
  • the first end of the DC/DC conversion circuit 201 is generally provided with a bus capacitor (not shown in the figure).
  • the voltage is equal to the output voltage of the battery cluster 10 , and then the second relay K2 is controlled to close. At this time, the voltage of the bus capacitor will not cause an impact to the battery cluster 10 and protect the battery cluster 10 .
  • the controller 100 is further configured to control the first relay K1 to be closed and the second relay K2 to be disconnected after the bypass or access to the battery pack is completed, and then to control the first relay K1 for a third preset time.
  • One relay K1 is open and the second relay K2 is closed.
  • the function of setting the third preset time is to make the first terminal of the DC/DC conversion circuit 201 and the output terminal of the battery cluster 10 charge and discharge after the current is limited by the first relay K1 and the first resistor R1 to reach the potential Balanced, reducing the impact on the battery cluster 10 .
  • the third preset time may be set according to the actual situation, which is not specifically limited in this embodiment of the present application.
  • the above slow-start circuit 60 may be integrated with the DC/DC conversion circuit 201, or the slow-start circuit 60 may be set independently, which is not specifically limited in this embodiment of the present application.
  • the power of each battery pack can be balanced, and by controlling the DC/DC conversion circuit and the slow-start circuit, bypassing or reconnecting the battery can be avoided.
  • the larger current impact during the pack affects the battery cluster and protects the battery cluster.
  • FIG. 7 is a flowchart of a method for judging the charging and discharging state of a battery pack provided by an embodiment of the present application.
  • the method includes the following steps:
  • S702 Determine whether the battery pack has reached a charging completion state.
  • S703 Determine whether the battery pack has reached a discharge completion state.
  • the battery pack is in a state of completion of discharge at this time, and can be bypassed.
  • the following describes the method of controlling each battery pack to achieve cell balance.
  • FIG. 8 this figure is a schematic diagram of a control method of an energy storage system provided by an embodiment of the present application.
  • S802 Determine whether the battery pack is in a charging state.
  • S805 Determine whether the number of remaining unbypassed battery packs is greater than 1.
  • S808 Bypass the battery pack whose first parameter value is greater than or equal to the first preset parameter value.
  • the battery packs whose first parameter value is greater than or equal to the first preset parameter value are bypassed in sequence until only one battery pack remains unbypassed.
  • the second parameter value corresponding to the battery pack is obtained first, and then the second parameter value corresponding to the battery pack is used to determine the first parameter value corresponding to the battery pack.
  • the second parameter value includes the total capacity of the battery pack, the energy state SOE value and the health state SOH value, and the first parameter value is the state of charge SOC value.
  • the first parameter value corresponding to the battery pack is directly obtained, where the first parameter value is a voltage value or a state-of-charge SOC value.
  • the first preset time is greater than or equal to the dead time of the first controllable switch, so as to avoid the short circuit between the positive output terminal and the negative output terminal of the battery pack caused by the simultaneous closure of the first controllable switch and the second controllable switch, This embodiment of the present application does not specifically limit the first preset time.
  • the remaining bypassed battery packs have achieved power balance.
  • the first parameter value of only one remaining battery pack is greater than or equal to the first preset parameter value, it means that the battery cluster is fully charged and no longer bypassed. Only the remaining battery packs are left, and each bypass circuit is controlled to reconnect the bypassed battery packs to the battery cluster.
  • the first controllable switch and the second controllable switch of the bypass circuit corresponding to the battery pack are first controlled to be turned off, and then the first controllable switch is controlled after a second preset time. closure.
  • the second preset time is greater than or equal to the dead time of the second controllable switch, so as to avoid the short circuit between the positive and negative output terminals of the battery pack caused by the simultaneous closure of the first controllable switch and the second controllable switch.
  • the second preset time is not specifically limited.
  • S810 Determine whether the number of remaining unbypassed battery packs is greater than 1.
  • the battery packs whose first parameter value is less than or equal to the second preset parameter value are bypassed in sequence until only one battery pack is left unbypassed.
  • S814 Control each bypass circuit to reconnect the bypassed battery pack to the battery cluster.
  • the remaining bypassed battery packs have achieved power balance.
  • the first parameter value of only one remaining battery pack is less than or equal to the second preset parameter value, it means that the battery cluster is discharged and no longer bypassed. Only the remaining battery packs are controlled, and each of the bypass circuits is controlled so that the bypassed battery packs are reconnected to the battery cluster.
  • the power of each battery pack can be balanced, and after the fully charged or discharged battery pack is cut off, other battery packs can still be charged with the maximum current or discharge, reducing the impact on the battery cluster current.
  • the maximum backup time is also achieved.
  • the bypass circuit can be controlled to bypass the battery pack where the abnormal battery is located, so as to remove the fault and ensure that the remaining battery packs can continue to operate normally.
  • the following describes the control method of the slow-start circuit and the DC/DC conversion circuit in the power conversion circuit.
  • the positive port of the output end of the battery cluster is connected to the positive port of the first end of the DC/DC conversion circuit through the slow-start circuit, or the negative port of the output end of the battery cluster is connected to the negative port of the first end of the DC/DC conversion circuit through the slow-start circuit .
  • the slow-start circuit specifically includes: a first relay K1, a second relay K2 and a first resistor R1.
  • the first relay K1 is connected in series with the first resistor R1 and then connected in parallel with the second relay K2.
  • this figure is a schematic diagram of another control method of an energy storage system provided by an embodiment of the present application.
  • the first terminal of the DC/DC conversion circuit is generally provided with a bus capacitor.
  • the voltage of the bus capacitor is equal to the output voltage of the battery cluster, and then the second terminal is controlled to be equal to the output voltage of the battery cluster.
  • the DC/DC conversion circuit can be controlled to start working.
  • this figure is a schematic diagram of yet another control method of an energy storage system provided by an embodiment of the present application.
  • S1002 Control the first relay K1 to be closed and the second relay K2 to be open, and then control the first relay K1 to be open and the second relay K2 to be closed after a third preset time.
  • the function of setting the third preset time is to make the first terminal of the DC/DC conversion circuit and the output terminal of the battery cluster charge and discharge after the current is limited by the first relay and the first resistor to achieve potential balance, reducing the Shock to the battery cluster.
  • the third preset time may be set according to the actual situation, which is not specifically limited in this embodiment of the present application.
  • the power of each battery pack can be balanced, and the DC/DC conversion circuit and the slow-start circuit can also be controlled to avoid bypassing or re-connecting the battery pack.
  • the large current impact will affect the battery cluster and protect the battery cluster.
  • the embodiment of the present application further provides a photovoltaic power generation system, which will be described in detail below with reference to the accompanying drawings.
  • this figure is a schematic diagram of a photovoltaic power generation system provided by an embodiment of the present application.
  • the illustrated photovoltaic power generation system includes: an energy storage system and a photovoltaic power generation terminal 301 .
  • a battery cluster and a power conversion circuit are connected to form an energy storage branch, and the energy storage system includes at least one energy storage branch.
  • the photovoltaic power generation end 301 specifically includes photovoltaic components and a power conversion system, which will be described in detail below.
  • Photovoltaic modules are used to generate direct current from light energy.
  • the power conversion system is used to convert the direct current generated by photovoltaic modules into alternating current.
  • the power conversion system includes a DC combiner box and a centralized inverter.
  • the centralized inverter includes an inverter circuit for inverting the DC power input from at least one DC combiner box into AC power.
  • the power of centralized inverters is relatively large.
  • the power conversion system includes a string inverter and an AC combiner box.
  • the DC side of the string inverter is connected to one or more photovoltaic modules.
  • the DC side of the string inverter is generally connected to multiple photovoltaic modules.
  • the power conversion system includes an inverter and a maximum power point tracking (MPPT) boost combiner box.
  • the MPPT boost combiner box is a boost converter, the input end of the MPPT boost combiner box is connected to the photovoltaic module, and the output end is connected to the input end of the inverter.
  • this figure is a schematic diagram of another photovoltaic power generation system provided by the embodiment of the present application.
  • the illustrated photovoltaic power generation system includes: an energy storage system and a photovoltaic assembly 80 .
  • a battery cluster and a power conversion circuit are connected to form an energy storage branch, and the energy storage system includes at least one energy storage branch.
  • Each cell cluster 10 is connected to at least one photovoltaic module 80 , and in practical applications, each cell cluster 10 is generally connected to a plurality of photovoltaic modules correspondingly.
  • Photovoltaic modules 80 are used to generate direct current from light energy to charge battery clusters 10
  • At least one (item) refers to one or more, and "a plurality” refers to two or more.
  • “And/or” is used to describe the relationship between related objects, indicating that there can be three kinds of relationships, for example, “A and/or B” can mean: only A, only B, and both A and B exist , where A and B can be singular or plural.
  • the character “/” generally indicates that the associated objects are an “or” relationship.
  • At least one item(s) below” or similar expressions thereof refer to any combination of these items, including any combination of single item(s) or plural items(s).

Abstract

本申请公开了一种储能系统、储能系统的控制方法及光伏发电系统，涉及电源技术领域。储能系统包括电池簇、功率变换电路和控制器。电池簇的输出端连接功率变换电路的第一端，功率变换电路的第二端连接储能系统的输出端。功率变换电路将电池簇提供的直流电转换为交流电后传输至交流电网，或将从功率变换电路的第二端获取的交流电转换为直流电后为电池簇充电。每个电池簇包括至少两个串联连接的储能模组，每个储能模组包括一个旁路电路和一个电池包，每个电池包包括多个电池。控制器根据各电池包的第一参数值，控制各旁路电路，以使各电池包的电量均衡。利用该储能系统能够使各电池包的电量均衡，降低了对电池簇电流的影响，减小了电量的浪费。

Description

一种储能系统、储能系统的控制方法及光伏发电系统 技术领域
本申请涉及电源技术领域，尤其涉及一种储能系统、储能系统的控制方法及光伏发电系统。
背景技术
随着现代社会能源短缺和环境污染问题的加剧，目前光伏发电和风力发电等发电方式得到了大规模的应用，此类新能源的波动性和不确定性的特点也日益突出，难以满足用户侧连续供电的要求。而随着电化学电池技术的发展与产能的剧增，电化学电池的成本下降，带来了电化学电池参与新能源发电系统的电力储能的契机。另外，由于应用电化学电池的储能系统具备灵活性、充放电的可控性、快速响应能力和高能量密度等特点，使得应用电化学电池的储能系统在发电侧的应用日渐广泛。
在发电侧增加应用电化学电池的储能系统，可以将发电量高或用电低谷时期消耗不掉的多余电能存储起来，在发电量低或者用电高峰时期放出，以使发电趋于平稳，减小对交流电网的冲击。
应用电化学电池的储能系统为了提升备电容量并且适应发电系统的电压等级要求，一般将多个电池包串联以形成高电压、大容量的电池簇。每个电池包中包括多个串联或混联的电池单体。由于电池的健康状态(State of Health，SOH)或原始的荷电状态(State of Charge，SOC)不同，使得各电池包的电量不均衡，导致各电池包充满电或放完电的用时存在差异。具体而言，当多个电池包串联形成电池簇时，由于所有的电池包的电流相同，因此需要按照最小的电池包电流对该电池簇的总电流进行限制，这会导致剩余电量多的电池包无法放完电，剩余电量少的电池包无法充满电，因此无法充分利用电池包的电量，限制了电池簇的电流且造成了电量的浪费。
发明内容
本申请提供了一种储能系统、储能系统的控制方法及光伏发电系统，能够使各电池包的电量均衡，降低了对电池簇电流的影响，进而减小了电量的浪费。
第一方面，本申请提供了一种储能系统，该储能系统应用于新能源发电场景下，储能系统的输出端连接交流电网，可以将发电量高或用电低谷时期消耗不掉的多余电能存储起来，在发电量低或者用电高峰时期放出，以减小对交流电网的冲击，该储能系统包括电池簇、功率变换电路和控制器。其中，电池簇的输出端连接功率变换电路的第一端，功率变换电路的第二端连接储能系统的输出端。功率变换电路用于将电池簇提供的直流电转换为交流电后传输至交流电网，或将从功率变换电路的第二端获取的交流电转换为直流电后为电池簇充电。当功率变换电路为电池簇充电时，交流电可以由交流电网提供，或者由新能源发电设备提供。每个电池簇包括至少两个串联连接的储能模组，每个储能模组均包括一个旁路电路和一个电池包，每个电池包包括多个电池，电池包内的多个电池可以采用串联或混连的方式连接。控制器根据各电池包的第一参数值，控制各旁路电路，以使各电池包的电量均衡。
本申请提供的储能系统，电池簇内每个电池包均对应连接了一个旁路电路，控制器根 据各电池包的第一参数值，控制各旁路电路，进而能够将电池包从电池簇中旁路。当电池簇充电时，被旁路的电池包先停止充电，随着电池包逐渐被旁路，使得电池簇内的各电池包的电量达到同步。当电池簇放电时，被旁路的电池包先停止放电，随着电池包逐渐被旁路，同样使得电池簇内的各电池包的电量达到同步。而当电池包被旁路后，其余电池包仍然可以以最大的电流进行充点或放电，因此电池簇的电流能够保持不变。综上，该储能系统能够使各电池包的电量均衡，降低了对电池簇电流的影响，进而减小了电量的浪费。此外，由于各电池包的电量均衡，因此还实现了最大备电时长。
控制器可以为专用集成电路(Application Specific Integrated Circuit，ASIC)、可编程逻辑器件(Programmable Logic Device，PLD)、数字信号处理器(Digital Signal Processor，DSP)或其组合。上述PLD可以是复杂可编程逻辑器件(Complex Programmable Logic Device，CPLD)、现场可编程逻辑门阵列(Field-programmable Gate Array，FPGA)、通用阵列逻辑(Generic Array Logic，GAL)或其任意组合。
控制器可以为一级控制器，或者多级控制器。当控制器为多级控制器时，上级控制器可以对下级控制器进行控制，下级控制器可以为多个。多级的控制器可以集成在印制电路板(Printed circuit board，PCB)上，或者在物理上分为多部分并分别设置在储能系统的不同位置的PCB上，各部分共同配合实现控制功能。
在一种可能的实现方式中，控制器具体用于当电池簇充电时，控制各旁路电路以旁路第一参数值大于或等于第一预设参数值的电池包，此时剩余电池包继续进行充电；以及当电池簇放电时，控制各旁路电路以旁路第一参数值小于或等于第二预设参数值的电池包，此时剩余电池包继续进行放电。当电池包被旁路后，其余电池包仍然可以以最大的电流进行充点或放电，因此电池簇的电流能够保持不变。
在一种可能的实现方式中，旁路电路包括第一可控开关和第二可控开关。电池包的正输出端连接第一可控开关的第一端，第一可控开关的第二端连接第二可控开关的第一端和储能模组的正输出端，第二可控开关的第二端连接电池模组的负输出端，电池包的负输出端连接储能模组的负输出端。
在一种可能的实现方式中，控制器具体用于先控制第一可控开关和第二可控开关均断开，第一预设时间后再控制第二可控开关闭合，以旁路电池包。当第一可控开关和第二可控开关均为功率开关器件时，第一预设时间大于或等于第一可控开关的死区时间，以避免第一可控开关和第二可控开关同时闭合导致电池包正输出端和负输出端之间短路。
在一种可能的实现方式中，控制器具体用于当电池簇充电时，依次旁路第一参数值大于或等于第一预设参数值的电池包，直至仅剩余一个电池包未被旁路，表征此时电池簇充电完毕，不再旁路该仅剩余的电池包；以及当电池簇放电时，依次旁路第一参数值小于或等于第二预设参数值的电池包，直至仅剩余一个电池包未被旁路，表征此时电池簇放电完毕，不再旁路该仅剩余的电池包。
在一种可能的实现方式中，控制器还用于当电池簇充电且仅剩余的一个电池包的第一参数值大于或等于第一预设参数值时，控制各旁路电路以使被旁路的电池包重新接入电池簇，以及当电池簇放电且仅剩余的一个电池包的第一参数值小于或等于第二预设参数值时， 控制各旁路电路以使被旁路的电池包重新接入电池簇。
在一种可能的实现方式中，控制器具体用于先控制第一可控开关和第二可控开关均断开，第二预设时间后再控制第一可控开关闭合，以使电池包重新接入电池簇。当第一可控开关和第二可控开关均为功率开关器件时，第二预设时间大于或等于第二可控开关的死区时间，以避免第一可控开关和第二可控开关同时闭合导致电池包正输出端和负输出端之间短路。
在一种可能的实现方式中，功率变换电路包括直流/直流变换电路和直流/交流变换电路。直流/直流变换电路的第一端为功率变换电路的第一端，直流/直流变换电路的第二端连接直流/交流变换电路的第一端，直流/交流变换电路的第二端为功率变换电路的第二端。直流/直流变换电路，用于将电池簇提供的直流电进行直流变换后传输给直流/交流变换电路，或将直流/交流变换电路提供的直流电进行直流变换后传输给电池簇。直流/交流变换电路，用于将直流/直流变换电路提供的直流电变换为交流电，或将获取的交流电变换为直流电后传输给直流/直流变换电路。控制器还用于在旁路电池包或接入电池包前，控制直流/直流变换电路停止工作。
在一种可能的实现方式中，储能系统还包括缓启电路，电池簇的输出端的正端口通过缓启电路连接直流/直流变换电路的第一端的正端口，或者电池簇的输出端的负端口通过缓启电路连接直流/直流变换电路的第一端的负端口。缓启电路包括：第一继电器、第二继电器和第一电阻。其中，第一继电器与第一电阻串联后与第二继电器并联。控制器还用于在旁路电池包或接入电池包前，控制第一继电器和第二继电器断开。
在一种可能的实现方式中，控制器还用于当完成对电池包的旁路或接入后，控制直流/直流变换电路的第一端的电压等于电池簇的输出电压，然后控制第二继电器闭合。直流/直流变换电路的第一端一般设置有母线电容，控制器通过控制直流/直流变换电路第一端的电压等于电池簇的输出电压，使得母线电容的电压等于电池簇的输出电压，再控制第二继电器闭合，此时母线电容的电压不会对电池簇造成冲击，保护了电池簇。
在一种可能的实现方式中，控制器还用于当完成对电池包的旁路或接入后，控制第一继电器闭合且第二继电器断开，第三预设时间后再控制第一继电器断开且第二继电器闭合。
通过设置第三预设时间，使直流/直流变换电路的第一端和电池簇的输出端之间，通过第一继电器和第一电阻限流后进行充放电以达到电位均衡，降低了对电池簇的冲击。
在一种可能的实现方式中，控制器包括第一控制器和至少两个第二控制器。第二控制器与电池包一一对应连接。第二控制器用于获取对应的电池包的第二参数值，并将第二参数值发送给第一控制器。第一控制器用于利用所有电池包的第二参数值，确定所有电池包的第一参数值，当电池簇充电时，确定第一参数值大于或等于第一预设参数值的电池包为待旁路电池包，以及当电池簇放电时，确定第一参数值小于或等于第二预设参数值的电池包为待旁路电池包，然后向第二控制器发送控制指令。控制指令用于指示对应的第二控制器控制旁路电路旁路待旁路电池包。
第二控制器为电池电控单元(Battery Monitoring Unit，BMU)，第一控制器为电池控制单元(Battery Control Unit，BCU)。
在一种可能的实现方式中，第二参数值包括电池包的总容量、能量状态SOE值和健康状态SOH值，第一参数值为荷电状态SOC值。
在一种可能的实现方式中，控制器包括第一控制器和至少两个第二控制器。第二控制器与电池包一一对应连接。第二控制器获取对应的电池包的第一参数值，并将第一参数值发送给第一控制器。
第一控制器当电池簇充电时，确定第一参数值大于或等于第一预设参数值的电池包为待旁路电池包，以及当电池簇放电时，确定第一参数值小于或等于第二预设参数值的电池包为待旁路电池包，然后向第二控制器发送控制指令。控制指令用于指示对应的第二控制器控制旁路电路旁路待旁路电池包。
在一种可能的实现方式中，第一参数值为电压值或者荷电状态SOC值。
第二方面，本申请还提供了一种储能系统的控制方法该方法应用于以上实现方式提供的储能系统，方法包括：
根据各电池包的第一参数值，控制各旁路电路，以使各电池包的电量均衡。
利用以上控制方法，能够使各电池包的电量均衡，当充满电或放完电的电池包被切除后，其它的电池包仍可以以最大的电流进行充电或放电，降低了对电池簇电流的影响。此外，由于各电池包的电量均衡，因此还实现了最大备电时长。另一方面，当确定电池出现异常时，可以通过控制旁路电路，旁路异常电池所在的电池包，实现对于故障的切除，确保其余电池包可以继续正常运行。
在一种可能的实现方式中，根据各电池包的第一参数值，控制各旁路电路，具体包括：
当电池簇充电时，控制各旁路电路以旁路第一参数值大于或等于第一预设参数值的电池包；
当电池簇放电时，控制各旁路电路以旁路第一参数值小于或等于第二预设参数值的电池包。
在一种可能的实现方式中，当电池簇充电时，控制各旁路电路以旁路第一参数值大于或等于第一预设参数值的电池包，具体包括：
当电池簇充电时，依次旁路第一参数值大于或等于第一预设参数值的电池包，直至仅剩余一个电池包未被旁路；
当电池簇放电时，控制各旁路电路以旁路第一参数值小于或等于第二预设参数值的电池包，具体包括：
当电池簇放电时，依次旁路第一参数值小于或等于第二预设参数值的电池包，直至仅剩余一个电池包未被旁路。
在一种可能的实现方式中，该方法还包括：
当电池簇充电时，当仅剩余的一个电池包的第一参数值大于或等于第一预设参数值时，控制各旁路电路以使被旁路的电池包重新接入电池簇；
当电池簇放电时，当仅剩余的一个电池包的第一参数值小于或等于第二预设参数值时，控制各旁路电路以使被旁路的电池包重新接入电池簇。
在一种可能的实现方式中，方法还包括：
在旁路电池包或接入电池包前，控制与电池簇的输出端连接的直流/直流变换电路停止工作，直流/直流变换电路的第一端连接电池簇的输出端；
当完成对电池包的旁路或接入后，控制直流/直流变换电路的第一端的电压等于电池簇的输出电压，然后控制直流/直流变换电路开始工作。
在一种可能的实现方式中，方法还包括：
获取所有电池包对应的第二参数值；
利用所有电池包对应的第二参数值，确定所有电池包的第一参数值。
在一种可能的实现方式中，第二参数值包括电池包的总容量、能量状态SOE值和健康状态SOH值，第一参数值为荷电状态SOC值。
在一种可能的实现方式中，第一参数值为电压值或者荷电状态SOC值。
第三方面，本申请还提供了一种光伏发电系统，该光伏发电系统包括以上实现方式提供的储能系统，还包括光伏发电端。其中，光伏发电端的输出端用于连接交流电网。光伏发电端用于利用光能产生交流电。该交流电可以传输至交流电网，或者通过储能系统的功率变换电路后为电池簇进行充电。
第四方面，本申请还提供了一种光伏发电系统，该光伏发电系统包括以上实现方式提供的储能系统，还包括组件。光伏组件用于利用光能产生直流电以为电池簇充电。
本申请提供的光伏发电系统的电池簇内每个电池包均对应连接了一个旁路电路，控制器根据各电池包的第一参数值，控制各旁路电路，进而能够将电池包从电池簇中旁路。当电池簇充电时，被旁路的电池包先停止充电，随着电池包逐渐被旁路，使得电池簇内的各电池包的电量达到同步。当电池簇放电时，被旁路的电池包先停止放电，随着电池包逐渐被旁路，同样使得电池簇内的各电-池包的电量达到同步。而当电池包被旁路后，其余电池包仍然可以以最大的电流进行充点或放电，因此电池簇的电流能够保持不变。综上，该光伏发电系统能够使各电池包的电量均衡，降低了对电池簇电流的影响，进而减小了电量的浪费。此外，由于各电池包的电量均衡，因此还实现了最大备电时长。
附图说明
图1为本申请实施例提供的一种示意性的新能源发电系统；
图2为本申请实施例提供的一种储能系统的示意图；
图3为本申请实施例提供的一种电池簇的示意图；
图4为本申请实施例提供的另一种电池簇的示意图；
图5为本申请实施例提供的另一种储能系统的示意图；
图6为本申请实施例提供的又一种储能系统的示意图；
图7为本申请实施例提供的判断电池包充放电状态的方法流程图；
图8为本申请实施例提供的一种储能系统的控制方法的示意图；
图9为本申请实施例提供的另一种储能系统的控制方法的示意图；
图10为本申请实施例提供的又一种储能系统的控制方法的示意图；
图11为本申请实施例提供的一种光伏发电系统的示意图；
图12为本申请实施例提供的另一种光伏发电系统的示意图。
具体实施方式
为了使本领域技术人员更好地理解本申请实施例提供的技术方案，下面先介绍本申请技术方案的应用场景。
参见图1，该图为本申请实施例提供的一种示意性的新能源发电系统。
该新能源发电系统包括电池簇10、功率变换电路20、新能源发电端30以及负载40。
其中，新能源发电端30用于输出交流电，由于新能源发电端30具有波动性和不确定性的特点，其发电量存在波动。当新能源发电端30输出的交流电高于交流电网50的用电需求时，多余的电量通过功率变换电路20转换为直流电后为电池簇10充电。当新能源发电端30输出的交流电低于交流电网50的用电需求时，功率变换电路20将电池簇10输出的直流电转换为交流电后输出至交流电网50，以使交流电网50趋于平稳。
以新能源发电端30为光伏发电端为例，新能源发电端30包括了光伏组件和直流(Direct Current，DC)/交流(Alternating Current，AC)变换电路(可以也称为称逆变电路或者逆变器)。光伏组件利用光能产生直流电，DC/AC变换电路将直流电转换为交流电后输出至交流电网50和/或为电池簇10充电。
负载40为新能源发电系统的用电设备，本申请对此不作具体限定。
电池簇10包括多个电池包，每个电池包中包括多个串联或混联的电池单体。由于各个电池的SOH或原始的SOC不同，使得各电池包的电量不均衡，导致各电池包充满电或放完电的用时存在差异。具体而言，当多个电池包串联形成电池簇时，由于所有的电池包的电流相同，因此需要按照最小的电池包电流对该电池簇的总电流进行限制，这会导致剩余电量多的电池包无法放完电，剩余电量少的电池包无法充满电，因此无法充分利用电池包的电量，限制了电池簇的电流且造成了电量的浪费。当下一次充电或放电时，由于各电池包的电量不均衡，导致电池簇不能实现最大备电时长。
为了解决以上技术问题，本申请提供了一种储能系统、储能系统的控制方法及光伏发电系统，该储能系统的电池簇内的电池包均对应连接了一个旁路电路，控制器根据各电池包的第一参数值，控制各旁路电路，进而能够将电池包从电池簇中旁路，进而使各个电池包的电量均衡。当电池包被旁路后，其余电池包仍然可以以最大的电流进行充点或放电，因此电池簇的电流能够保持不变。利用该储能系统能够使各电池包的电量均衡，降低了对电池簇电流的影响，进而减小了电量的浪费，还实现了最大备电时长。
为了使本技术领域的人员更清楚地理解本申请方案，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行描述。
本申请说明中的“第一”、“第二”等用词仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量
在本申请中，除非另有明确的规定和限定，术语“连接”应做广义理解，例如，“连接”可以是固定连接，也可以是可拆卸连接，或成一体；可以是直接连接，也可以通过中间媒介间接连接。
一并参见图2和图3。其中，图2为本申请实施例提供的一种储能系统的示意图；图3为本申请实施例提供的一种电池簇的示意图。
该储能系统包括电池簇10、功率变换电路20和控制器100。
电池簇10的输出端连接功率变换电路20的第一端，功率变换电路20的第二端连接储能系统的输出端，用于为交流电网输出电能。
功率变换电路20用于将电池簇10提供的直流电转换为交流电后传输至交流电网50，或将从功率变换电路20的第二端获取的交流电转换为直流电后为电池簇充电。即功率变换电路20能够实现双向的功率变换，既可以利用交流电网或新能源发电端提供的交流电为电池簇10充电，也可以利用电池簇10输出的直流电为交流电网50供电。
参见图3，每个电池10包括至少两个串联连接的储能模组。图中储能模组以10a 1-10a m表示。
其中，每个储能模组均包括一个旁路电路和一个电池包，每个电池包内包括多个电池。
以储能模组以10a 1为例，其包括旁路电路101b 1和电池包101a 1。
各电池包内的电池可以采用串联或者混连的方式连接，本申请实施例不作具体限定。图3及以下说明中均以电池包内的各电池采用串联的方式连接为例。
本申请实施例中的旁路电路包括两个工作状态。其中，在第一个工作状态下，对应的电池包未被旁路，能够使对应的电池包串联接入电池簇；在第二个工作状态下，对应的电池包被旁路，即电池包相当于被从电池簇中切除，具体的，当电池簇处于充电状态时，电池包被旁路后停止继续充电，当电池簇处于放电状态时，电池包被旁路后停止继续放电。
第一参数值能够表征电池包的电量状态，控制器100根据第一参数值可以确定对应的电池包的电量，通过控制旁路电路在以上两个工作状态间进行切换，以使各电池包的电量均衡。
以上控制器可以为专ASIC、PLD、DSP或其组合。上述PLD可以是CPLD、FPGA、GAL或其任意组合，本申请实施例对此不作具体限定。
本申请实施例以上说明中的控制器可以为一级控制器，或者多级控制器。当控制器为多级控制器时，上级控制器可以接受下级控制器发送的信息，下级控制器的数量可以为多个，上级控制器可以对下级控制器进行控制。多级控制器可以独立集成在印制电路板(Printed circuit board，PCB)上，或者在物理上分为多部分并分别设置在储能系统的不同位置的PCB上，各部分共同配合实现控制功能，本申请实施例对此不作具体限定。
电池包中的电池单体可以为锂离子电池、铅酸电池、超级电容等类型，或者以上类型的组合，本申请实施例在此不作具体限定。
本申请实施例提供的储能系统，当电池簇充电时，被旁路的电池包先停止充电，随着电池包逐渐被旁路，使得电池簇内的各电池包的电量达到同步。当电池簇放电时，被旁路的电池包先停止放电，随着电池包逐渐被旁路，同样使得电池簇内的各电池包的电量达到同步。而当电池包被旁路后，其余电池包仍然可以以最大的电流进行充点或放电，因此电池簇的电流能够保持不变。综上，该储能系统能够使各电池包的电量均衡，降低了对电池簇电流的影响，进而减小了电量的浪费。此外，由于各电池包的电量均衡，因此还实现了最大备电时长。
下面结合储能系统的具体实现方式进行说明。
参见图4，该图为本申请实施例提供的另一种电池簇的示意图。
图示控制器包括两级控制器：第一级控制器1001和第二级控制器1002a1-1002am。
第二级控制器的数量与电池包的数量一致，第二级控制器与电池包一一对应连接。各第二控制器与第一控制器1001连接，各第二控制器与第一控制器1001之间可以进行通信。
图示的每个旁路电路均包括第一可控开关和第二可控开关。电池簇内包括m个电池模组，则该电池簇内的第一可控开关为S11-Sm1，电池簇内的第二可控开关为S12-Sm2。
以储能模组10a1为例，其中的第一可控开关为S11，第二可控开关为S12。电池包101a1的正输出端连接第一可控开关S11的第一端，第一可控开关S11的第二端连接第二可控开关S12的第一端和储能模组10a1的正输出端，第二可控开关S12的第二端连接电池模组10a2的负输出端，电池包101a1的负输出端连接储能模组10a1的负输出端。
类似的，S21和S22与电池模组101a 2对应，依次类推到Sm1和Sm2与电池模组101a m对应。
各电池模组中的第一可控开关和第二可控开关可以为绝缘栅双极型晶体管(Insulated Gate Bipolar Transistor，IGBT)、金属氧化物半导体场效应晶体管(Metal Oxide Semiconductor Filed Effect Transistor，MOSFET)、碳化硅场效应管(Silicon Carbide Metal Oxide Semiconductor，SiC MOSFET)、机械开关或者以上各种的组合等。第二控制器通过向第一可控开关和第二可控开关发送控制信号来控制其的工作状态，在一种可能的实现方式中，该控制信号为脉冲宽度调制(Pulse width modulation，PWM)信号。
以第一可控开关和第二可控开关均为N型MOSFET为例，则第一可控开关和第二可控开关的第一端为漏极，第二端为栅极。S11的体二极管方向与电池电压的方向相反，S12的体二极管的方向与S11的体二极管方向相反，进而防止电池模组通过体二极管直接短路。
在另一些实施例中，也可以用额外并联的二极管替代开关器件的体二极管。
以上的开关器件可以设置在电池模组内部，或者第二控制器集成在一起，或者独立设计于PCB上后再集成在电池包的内部或外部，本申请实施例对此不作具体限定。
在一些实施例中，第二控制器为电池电控单元，第一控制器为电池控制单元。
控制器具体用于当电池簇充电时，控制各旁路电路以旁路第一参数值大于或等于第一预设参数值的电池包，以及当所述电池簇放电时，控制各旁路电路以旁路第一参数值小于或等于第二预设参数值的电池包，下面具体说明该控制器的工作原理。
下面首先说明第一种控制旁路电路的实现方式。
各第二控制器获取对应的电池包的第二参数值，并将第二参数值发送给第一控制器。其中，第二参数值包括电池包的总容量Q、能量状态(State of Energy，SOE)值和健康状态(State of Health，SOH)值。
其中。SOE值表征电池包当前可控电量。SOH表征当前电池包相对于新电池包存储电能的能力，以百分比的形式表示可以理解为当前可用容量与总容量Q的比值。
第一控制器利用获取的所有电池包的第二参数值，确定所有电池对应的第一参数值，当电池簇充电时，确定第一参数值大于或等于第一预设参数值的电池包为待旁路电池包， 以及当电池簇放电时，确定第一参数值小于或等于第二预设参数值的电池包为待旁路电池包。
其中，第一参数值为荷电状态(State of Charge，SOC)值。第一预设参数值和第二预设参数值根据实际情况预先设定并保存在第一控制器中，待使用时进行调用，本申请实施例对第一预设参数值和第二预设参数值不作具体限定。
具体的，第一控制器可以通过下式确定SOC值：
Figure PCTCN2021086070-appb-000001
式(1)中获取的SOC为电池包当前实际的SOC，即当前电量相对于当前的容量的比值。
第一控制器然后向第二控制器发送控制指令。该控制指令用于指示对应的第二控制器控制旁路电路旁路待旁路电池包。
例如当确定电池包101a1为待旁路电池包时，第一控制器发送的控制指令用于指示第二控制器1002a1通过控制S11和S12，以使电池包101a1被旁路。
当电池包101a1正常串联接入电池簇时，第一可控开关S11闭合，第二可控开关S12断开。当第二控制器1002a1旁路电池包101a1时，先控制器第一可控开关S11和第二可控开关S12均断开，待第一预设时间后在控制第二可控开关S12闭合。
其中，第一预设时间大于或等于第一可控开关S11的死区时间(dead time)，以避免第一可控开关S11和第二可控开关S12同时闭合导致电池包101a1正输出端和负输出端之间短路，本申请实施例对第一预设时间不作具体限定。
旁路其它电池包时的原理类似，本申请实施例在此不再赘述。
当电池簇充电时，各个电池包的电量可能不均衡，使得各个电池包充满电的用时可能不同。第一控制器依次确定第一参数值大于或等于第一预设参数值的电池包为待旁路电池包，并向第二控制器发送控制指令，以使第二控制器控制各旁路电路依次旁路各待旁路电池包，直至仅剩余一个电池包未被旁路，此时其余被旁路的电池包已经实现了电量平衡。
此时仅剩余一个电池包继续充电，当第一控制器确定该仅剩余的电池包的第一参数值大于或等于第一预设参数值时，表征此时电池簇充电完毕，不再旁路该仅剩余的电池包，而通过第二控制器控制所有被旁路的电池包重新接入电池簇。
当电池簇放电时，各个电池包的电量可能不均衡，使得各个电池包放完电的用时可能不同。第一控制器依次确定第一参数值小于或等于第二预设参数值的电池包为待旁路电池包，并向第二控制器发送控制指令，以使第二控制器控制各旁路电路依次旁路各待旁路电池包，直至仅剩余一个电池包未被旁路，此时其余被旁路的电池包已经实现了电量平衡。
仅剩余一个电池包继续放电，当第一控制器确定该仅剩余的电池包的第一参数值小于或等于第二预设参数值时，表征此时电池簇放电完毕，不再旁路该仅剩余的电池包，而通过第二控制器控制所有被旁路的电池包重新接入电池簇。
以将电池包101a1重新接入电路为例，当电池包101a1处于被旁路的状态时，第一可控开关S11断开，第二可控开关S12闭合。控制器控制电池包101a1重新接入电路时，先控制第一可控开关S11和第二可控开关S12均断开，第二预设时间后再控制第一可控开关闭合S11。
其中，第二预设时间大于或等于第二可控开关S12的死区时间(dead time)，以避免第一可控开关S11和第二可控开关S12同时闭合导致电池包101a1正负输出端之间短路，本申请实施例对第二预设时间不作具体限定。
旁路其它电池包时的原理类似，本申请实施例在此不再赘述。
实际应用中，当第一可控开关S11和第二可控开关S12采用规格相同的器件时，以上的第一预设时间和第二预设时间可以相同。
下面说明第二种控制旁路电路的实现方式。
各第二控制器，用于获取对应的电池包的第一参数值，并将第一参数值发送给第一控制器1001。该第一参数值为电压值或SOC值。
第一控制器当电池簇充电时，确定第一参数值大于或等于第一预设参数值的电池包为待旁路电池包，以及当电池簇放电时，确定第一参数值小于或等于第二预设参数值的电池包为待旁路电池包。然后第一控制器1001向各第二控制器发送控制指令。该控制指令用于指示对应的第二控制器控制旁路电路旁路待旁路电池包，下面具体说明。
当第一参数值为电压值时，第一预设参数值为第一预设电压值，第二预设参数值为第二预设电压值。当电池簇充电时，各个电池包的电量可能不均衡，使得各个电池包充满电的用时可能不同，表现为各个电池包的电压值不同。第一控制器依次确定电压值大于或等于第一预设电压值的电池包为待旁路电池包，并向第二控制器发送控制指令，以使第二控制器控制各旁路电路依次旁路各待旁路电池包，直至仅剩余一个电池包未被旁路，此时其余被旁路的电池包已经实现了电量平衡，并且完成了充电。
此时仅剩余一个电池包继续充电，当第一控制器确定该仅剩余的电池包的电压值大于或等于第一预设电压值时，表征此时电池簇充电完毕，不再旁路该仅剩余的电池包，而通过第二控制器控制所有被旁路的电池包重新接入电池簇。
当电池簇放电时，各个电池包的电量可能不均衡，使得各个电池包放完电的用时可能不同，因此各电池包的电压不同。第一控制器依次确定电压值小于或等于第二预设电压值的电池包为待旁路电池包，并向第二控制器发送控制指令，以使第二控制器控制各旁路电路依次旁路各待旁路电池包，直至仅剩余一个电池包未被旁路，此时其余被旁路的电池包已经实现了电量平衡，并且完成了放电。
仅剩余一个电池包继续放电，当第一控制器确定该仅剩余的电池包的电压值小于或等于第二预设电压值时，表征此时电池簇放电完毕，不再旁路该仅剩余的电池包，而通过第二控制器控制所有被旁路的电池包重新接入电池簇。
控制器控制旁路电路，以使电池包被旁路或者重新串联接入电池簇的实现方式与以上说明相同，在此不再赘述。
以上说明中以第一参数值为电压值为例，当第一参数值为SOC值时，第一预设参数值为第一预设SOC值，第二预设参数值为第二预设SOC值。控制器的具体工作过程与以上说明类似，本实施例在此不再赘述。
综上所述，该储能系统能够使各电池包的电量均衡，当充满电或放完电的电池包被切除后，其它的电池包仍可以以最大的电流进行充电或放电，降低了对电池簇电流的影响。 此外，由于各电池包的电量均衡，因此还实现了最大备电时长。另一方面，当确定电池出现异常时，可以通过控制旁路电路，旁路异常电池所在的电池包，实现对于故障的切除，确保其余电池包可以继续正常运行。
本申请实施例中的控制器还可以控制功率变换电路的工作状态，下面结合附图具体说明。
参见图5，该图为本申请实施例提供的另一种储能系统的示意图。
该储能系统的功率变换电路20包括直流/直流变换电路201和直流/交流变换电路202。
其中，直流/直流变换电路201的第一端为功率变换电路20的第一端，直流/直流变换电路201的第二端连接直流/交流变换电路202的第一端，直流/交流变换电路202的第二端为功率变换电路201的第二端。
直流/直流变换电路201用于将电池簇10提供的直流电进行直流变换后传输给直流/交流变换电202路，或将直流/交流变换电路202提供的直流电进行直流变换后传输给电池簇10，进而对电池簇10进行充电。
直流/交流变换电路202用于将直流/直流变换电路201提供的直流电变换为交流电，或将获取的交流电变换为直流电后传输给直流/直流变换电路201，直流/交流变换电路202的第二端可以从交流电网或者新能源发电端处获得交流电。
在一些实施例中，直流/交流变换电路202为一种双向直流/交流变换器，可选用中性点箝位T型三电平电路、中性点箝位(Neutral Point Clamped，NPC)电路、有源中点箝位((Active Neutral Point Clamped，ANPC)电路、飞跨电容多电平电路等。由于单体电池的端口电压随储能容量进行变化，使得电池簇的端口输出电压为一个宽范围的输出电压，因此为了匹配电池簇端口电压变化范围，直流/直流变换电路201、直流/交流变换电路202通常支持宽范围的输入输出能力。
在一些实施例中，在旁路或者接入电池包时，可以进行在线旁路或者在线接入，此时直流/直流变换电路201正常运行。
在另一些实施例中，控制器100还用于在旁路电池包或接入电池包前，控制直流/直流变换电路201停止工作，待电池包旁路或者接入后，再控制直流/直流变换电路201恢复工作。其中，直流/直流变换电路201停止工作即控制直流/直流变换电路201关机，或停止向直流/直流变换电路201发送控制信号。
下面具体说明对直流/直流变换电路的控制方式。
参见图6，该图为本申请实施例提供的又一种储能系统的示意图。
图示储能系统还包括缓启电路60，电池簇10的输出端的正端口通过缓启电路60连接直流/直流变换电路201的第一端的正端口，或者电池簇10的输出端的负端口通过缓启电路60连接直流/直流变换电路201的第一端的负端口。图6中示出了缓启电路60连接直流/直流变换电路201的第一端的正端口时的实现方式。
缓启电路60具体包括：第一继电器K1、第二继电器K2和第一电阻R1。
其中，第一继电器K1与第一电阻R1串联后与第二继电器K2并联。
控制器100还用于在旁路电池包或接入电池包前，控制第一继电器和第二继电器断开，进而使得直流/直流变换电路201停止工作。
进一步的，为例保护电池簇，在一些实施例中，控制器100还用于当完成对电池包的旁路或接入后，控制直流/直流变换电路201的第一端的电压等于电池簇10的输出电压，然后控制第二继电器K2闭合。
直流/直流变换电路201的第一端一般设置有母线电容(图中未示出)，控制器100通过控制直流/直流变换电路201第一端的电压等于电池簇10的输出电压，使得母线电容的电压等于电池簇10的输出电压，再控制第二继电器K2闭合，此时母线电容的电压不会对电池簇10造成冲击，保护了电池簇10。
在另一些实施例中，控制器100还用于当完成对电池包的旁路或接入后，先控制第一继电器K1闭合且第二继电器K2断开，第三预设时间后再控制第一继电器K1断开且第二继电器K2闭合。
设置第三预设时间的作用为：使直流/直流变换电路201的第一端和电池簇10的输出端之间，通过第一继电器K1和第一电阻R1限流后进行充放电以达到电位均衡，降低了对电池簇10的冲击。第三预设时间可以根据实际情况设定，本申请实施例在此不作具体限定。
以上的缓启电路60可以与直流/直流变换电路201集成在一起，或者缓启电路60独立设置，本申请实施例在此不作具体限定。
综上所述，利用本申请实施例提供的储能系统，能够使各电池包的电量均衡，还可以通过对直流/直流变换电路和缓启电路进行控制，避免了在旁路或者重新接入电池包时较大的电流冲击对电池簇造成影响，保护了电池簇。
基于以上实施例提供的储能系统，本申请实施例还提供了一种储能系统的控制方法，应用于以上实施例提供的储能系统，该方法包括：根据各电池包的第一参数值，控制各电池包对应的旁路电路，以使各电池包的电量均衡，下面结合附图具体说明。
首先判断电池包的充放电状态。
参见图7，该图为本申请实施例提供的判断电池包充放电状态的方法流程图。
该方法包括以下步骤：
S701：启动。
S702：判断电池包是否达到充电完成状态。
若是，则执行S704，若否则执行S703。
S703：判断电池包是否达到放电完成状态。
若否，则继续重新进行判断，可以延时一段时间后重新执行S702，若是则执行S705。
S704：置电池包充电完成标志。
表征此时电池包处于充电完成状态，可以进行旁路。
S705：置电池包放电完成标志。
表征此时电池包处于放电完成状态，可以进行旁路。
S706：结束。
下面说明控制各电池包实现电量均衡方法。
参见图8，该图为本申请实施例提供的一种储能系统的控制方法的示意图。
S801：启动。
S802：判断电池包是否处于充电状态。
若是，则执行S803，否则，执行S804。
S803：当前电池包是否充电完成。
若是，则执行S805，否则，执行S806。
在一些实施例中，可以根据以上S704中的电池包充电完成标志确定当前电池包是否充电完成。
S804：当前电池包是否放电完成。
若是，则执行S810，否则，执行S811。
在一些实施例中，可以根据以上S705中的电池包放电完成标志确定当前电池包是否放电完成。
S805：判断剩余未被旁路电池包数量是否大于1。
若是，则执行S808，否则，执行S809。
S806：判断是否所有电池包均检测完毕。
若是，则执行S815，否则，执行S807。
S807：检测下一个电池包。
S808：旁路第一参数值大于或等于第一预设参数值的电池包。
即当电池簇充电时，依次旁路第一参数值大于或等于第一预设参数值的电池包，直至仅剩余一个电池包未被旁路。
在一些实施例中，首先获取电池包对应的第二参数值，再利用电池包对应的第二参数值，确定电池包对应的第一参数值。其中，二参数值包括电池包的总容量、能量状态SOE值和健康状态SOH值，第一参数值为荷电状态SOC值。
在另一些实施例中，直接获取电池包对应的第一参数值，该第一参数值为电压值或者荷电状态SOC值。
旁路电池包时，先控制该电池包对应的旁路电路的第一可控开关和第二可控开关均断开，待第一预设时间后在控制第二可控开关闭合。其中，第一预设时间大于或等于第一可控开关的死区时间，以避免第一可控开关和第二可控开关同时闭合导致该电池包正输出端和负输出端之间短路，本申请实施例对第一预设时间不作具体限定。
S809：控制各旁路电路以使被旁路的电池包重新接入电池簇。
此时其余被旁路的电池包已经实现了电量平衡，当仅剩余的一个电池包的第一参数值大于或等于第一预设参数值时，表征此时电池簇充电完毕，不再旁路该仅剩余的电池包，而控制各旁路电路以使被旁路的电池包重新接入电池簇。
当控制电池包重新接入电池簇时，先控制该电池包对应的旁路电路的第一可控开关和第二可控开关均断开，第二预设时间后再控制第一可控开关闭合。
其中，第二预设时间大于或等于第二可控开关的死区时间，以避免第一可控开关和第 二可控开关同时闭合导致电池包正负输出端之间短路，本申请实施例对第二预设时间不作具体限定。
S810：判断剩余未被旁路电池包数量是否大于1。
S811：判断是否所有电池包均检测完毕。
若是，则执行S815，否则，执行S812。
S812：检测下一个电池包。
S813：旁路第一参数值小于或等于第二预设参数值的电池包。
即当电池簇放电时，依次旁路第一参数值小于或等于第二预设参数值的电池包，直至仅剩余一个电池包未被旁路。
S814：控制各旁路电路以使被旁路的电池包重新接入电池簇。
此时其余被旁路的电池包已经实现了电量平衡，当仅剩余的一个电池包的第一参数值小于或等于第二预设参数值时，表征此时电池簇放电完毕，不再旁路该仅剩余的电池包，而控制各所述旁路电路以使被旁路的电池包重新接入所述电池簇。
S815：结束。
以上步骤的划分及顺序仅是为了方便说明，并不构成对于本申请技术方案的限定，本领域技术人员可以根据实际情况进适当调整。
综上所述，利用本申请实施例提供的控制方法，能够使各电池包的电量均衡，当充满电或放完电的电池包被切除后，其它的电池包仍可以以最大的电流进行充电或放电，降低了对电池簇电流的影响。此外，由于各电池包的电量均衡，因此还实现了最大备电时长。另一方面，当确定电池出现异常时，可以通过控制旁路电路，旁路异常电池所在的电池包，实现对于故障的切除，确保其余电池包可以继续正常运行。
下面说明对功率变换电路中的缓启电路以及直流/直流变换电路的控制方法。
电池簇的输出端的正端口通过缓启电路连接直流/直流变换电路的第一端的正端口，或者电池簇的输出端的负端口通过缓启电路连接直流/直流变换电路的第一端的负端口。
缓启电路具体包括：第一继电器K1、第二继电器K2和第一电阻R1。第一继电器K1与第一电阻R1串联后与第二继电器K2并联。
关于直流/直流变换电路的具体实现方式和工作原理可以参见以上实施例中的说明，本申请实施例在此不再赘述。
参见图9，该图为本申请实施例提供的另一种储能系统的控制方法的示意图。
S901：在旁路电池包或接入电池包前，控制与电池簇的输出端连接的直流/直流变换电路停止工作，直流/直流变换电路的第一端连接电池簇的输出端。
S902：完成对电池包的旁路或接入后，控制直流/直流变换电路的第一端的电压等于电池簇的输出电压。
直流/直流变换电路的第一端一般设置有母线电容，通过控制直流/直流变换电路第一端的电压等于电池簇的输出电压，使得母线电容的电压等于电池簇的输出电压，再控制第二继电器闭合，此时母线电容的电压不会对电池簇造成冲击，保护了电池簇。
S903：控制第二继电器K2闭合。
待第二继电器K2闭合后，可以控制直流/直流变换电路开始工作。
参见图10，该图为本申请实施例提供的又一种储能系统的控制方法的示意图。
S1001：在旁路电池包或接入电池包前，控制与电池簇的输出端连接的直流/直流变换电路停止工作，并控制第一继电器K1和第二继电器K2均断开，直流/直流变换电路的第一端连接电池簇的输出端。
S1002：控制第一继电器K1闭合且第二继电器K2断开，第三预设时间后再控制第一继电器K1断开且第二继电器K2闭合。
设置第三预设时间的作用为：使直流/直流变换电路的第一端和电池簇的输出端之间，通过第一继电器和第一电阻限流后进行充放电以达到电位均衡，降低了对电池簇的冲击。第三预设时间可以根据实际情况设定，本申请实施例在此不作具体限定。
综上所述，利用本申请实施例提供的控制方法，能够使各电池包的电量均衡，还可以通过对直流/直流变换电路和缓启电路进行控制，避免了在旁路或者重新接入电池包时较大的电流冲击对电池簇造成影响，保护了电池簇。
基于以上实施例提供的储能系统，本申请实施例还提供了一种光伏发电系统，下面结合附图具体说明。
参见图11，该图为本申请实施例提供的一种光伏发电系统的示意图。
图示光伏发电系统包括：储能系统和光伏发电端301。
其中，储能系统包括电池簇10、功率变换电路20和控制器100。
一个电池簇和一个功率变换电路连接后形成一路储能支路，储能系统中包括至少一路储能支路。
关于储能系统的具体实现方式以及工作原理可以参见以上实施例中的相关说明，本申请实施例在此不再赘述。
光伏发电端301具体包括光伏组件和功率变换系统，下面具体说明。
光伏组件用于将利用光能产生直流电。
功率变换系统用于将光伏组件产生的直流电转换为交流电。
在一些实施例中，功率变换系统包括直流汇流箱和集中式逆变器。集中式逆变器包括逆变电路，用于将至少一个直流汇流箱输入的直流电逆变为交流电。集中式逆变器的功率都相对较大。
在另一些实施例中，功率变换系统包括组串式逆变器和交流汇流箱。组串式逆变器的直流侧接入一个或多个光伏组件，实际应用中，组串式逆变器的直流侧一般接入多个光伏组件。
组串式逆变器的功率相对集中式逆变器小，多采用室外模块化设计，包括两级功率变换电路，第一级为直流/直流变换电路，一般为升压电路，第二级为逆变电路。
在又一些实施例中，功率变换系统包括逆变器及最大功率点跟踪(Maximum power point tracking，MPPT)升压汇流箱。其中，MPPT升压汇流箱为一种升压变流器，MPPT升压汇流箱的输入端连接光伏组件，输出端连接逆变器的输入端。
光伏发电端的输出端连接交流电网，用于将产生的交流电传输至交流电网或者通过功率变换电路20为电池簇10充电。
参见图12，该图为本申请实施例提供的另一种光伏发电系统的示意图。
图示光伏发电系统包括：储能系统和光伏组件80。
一个电池簇和一个功率变换电路连接后形成一路储能支路，储能系统中包括至少一路储能支路。每个电池簇10连接至少一个光伏组件80，实际应用中，每个电池簇10一般对应连接多个光伏组件。
光伏组件80用于利用光能产生直流电以为电池簇10充电
本申请实施例提供的光伏发电系统的电池簇内每个电池包均对应连接了一个旁路电路，控制器根据各电池包的第一参数值，控制各旁路电路，进而能够将电池包从电池簇中旁路。当电池簇充电时，被旁路的电池包先停止充电，随着电池包逐渐被旁路，使得电池簇内的各电池包的电量达到同步。当电池簇放电时，被旁路的电池包先停止放电，随着电池包逐渐被旁路，同样使得电池簇内的各电-池包的电量达到同步。而当电池包被旁路后，其余电池包仍然可以以最大的电流进行充点或放电，因此电池簇的电流能够保持不变。综上，该储能系统能够使各电池包的电量均衡，降低了对电池簇电流的影响，进而减小了电量的浪费。此外，由于各电池包的电量均衡，因此还实现了最大备电时长。
应当理解，在本申请中，“至少一个(项)”是指一个或者多个，“多个”是指两个或两个以上。“和/或”，用于描述关联对象的关联关系，表示可以存在三种关系，例如，“A和/或B”可以表示：只存在A，只存在B以及同时存在A和B三种情况，其中A，B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系。“以下至少一项(个)”或其类似表达，是指这些项中的任意组合，包括单项(个)或复数项(个)的任意组合。例如，a，b或c中的至少一项(个)，可以表示：a，b，c，“a和b”，“a和c”，“b和c”，或“a和b和c”，其中a，b，c可以是单个，也可以是多个。
以上所述，以上实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的精神和范围。

Claims (25)

  1. 一种储能系统，其特征在于，所述储能系统的输出端用于连接交流电网，所述储能系统包括：电池簇、功率变换电路和控制器；
    所述电池簇的输出端连接所述功率变换电路的第一端，所述功率变换电路的第二端连接所述储能系统的输出端；
    所述功率变换电路，用于将所述电池簇提供的直流电转换为交流电后传输至所述交流电网，或将从所述功率变换电路的第二端获取的交流电转换为直流电后为所述电池簇充电；
    每个所述电池簇包括至少两个串联连接的储能模组，每个所述储能模组均包括一个旁路电路和一个电池包，每个所述电池包包括多个电池；
    所述控制器，用于根据各所述电池包的第一参数值，控制各所述旁路电路，以使各所述电池包的电量均衡。
  2. 根据权利要求1所述的储能系统，其特征在于，所述控制器，具体用于当所述电池簇充电时，控制各所述旁路电路以旁路第一参数值大于或等于第一预设参数值的电池包，以及当所述电池簇放电时，控制各所述旁路电路以旁路第一参数值小于或等于第二预设参数值的电池包。
  3. 根据权利要求2所述的储能系统，其特征在于，所述旁路电路包括第一可控开关和第二可控开关；
    所述电池包的正输出端连接所述第一可控开关的第一端，所述第一可控开关的第二端连接所述第二可控开关的第一端和所述储能模组的正输出端，所述第二可控开关的第二端连接所述电池模组的负输出端，所述电池包的负输出端连接所述储能模组的负输出端。
  4. 根据权利要求3所述的储能系统，其特征在于，所述控制器，具体用于先控制所述第一可控开关和第二可控开关均断开，第一预设时间后再控制所述第二可控开关闭合，以旁路所述电池包。
  5. 根据权利要求3或4所述的储能系统，其特征在于，所述控制器，具体用于当所述电池簇充电时，依次旁路第一参数值大于或等于所述第一预设参数值的电池包，直至仅剩余一个电池包未被旁路；以及当所述电池簇放电时，依次旁路第一参数值小于或等于所述第二预设参数值的电池包，直至仅剩余一个电池包未被旁路。
  6. 根据权利要求5所述的储能系统，其特征在于，所述控制器，还用于当所述电池簇充电且仅剩余的一个电池包的第一参数值大于或等于第一预设参数值时，控制各所述旁路电路以使被旁路的电池包重新接入所述电池簇，以及当所述电池簇放电且仅剩余的一个电池包的第一参数值小于或等于第二预设参数值时，控制各所述旁路电路以使被旁路的电池包重新接入所述电池簇。
  7. 根据权利要求6所述的储能系统，其特征在于，所述控制器，具体用于先控制所述第一可控开关和第二可控开关均断开，第二预设时间后再控制所述第一可控开关闭合，以使所述电池包重新接入所述电池簇。
  8. 根据权利要求1-7中任一项所述的储能系统，其特征在于，所述功率变换电路包括直流/直流变换电路和直流/交流变换电路；
    所述直流/直流变换电路的第一端为所述功率变换电路的第一端，所述直流/直流变换电路的第二端连接所述直流/交流变换电路的第一端，所述直流/交流变换电路的第二端为所述功率变换电路的第二端；
    所述直流/直流变换电路，用于将所述电池簇提供的直流电进行直流变换后传输给所述直流/交流变换电路，或将所述直流/交流变换电路提供的直流电进行直流变换后传输给所述电池簇；
    所述直流/交流变换电路，用于将所述直流/直流变换电路提供的直流电变换为交流电，或将获取的交流电变换为直流电后传输给所述直流/直流变换电路；
    所述控制器，还用于在旁路所述电池包或接入所述电池包前，控制所述直流/直流变换电路停止工作。
  9. 根据权利要求8所述的储能系统，其特征在于，所述储能系统还包括缓启电路，所述电池簇的输出端的正端口通过所述缓启电路连接所述直流/直流变换电路的第一端的正端口，或者所述电池簇的输出端的负端口通过所述缓启电路连接所述直流/直流变换电路的第一端的负端口，所述缓启电路包括：第一继电器、第二继电器和第一电阻；
    所述第一继电器与所述第一电阻串联后与所述第二继电器并联；
    所述控制器，还用于在旁路所述电池包或接入所述电池包前，控制所述第一继电器和第二继电器断开。
  10. 根据权利要求9所述的储能系统，其特征在于，所述控制器还用于当完成对所述电池包的旁路或接入后，控制所述直流/直流变换电路的第一端的电压等于所述电池簇的输出电压，然后控制所述第二继电器闭合。
  11. 根据权利要求9所述的储能系统，其特征在于，所述控制器还用于当完成对所述电池包的旁路或接入后，控制所述第一继电器闭合且第二继电器断开，第三预设时间后再控制所述第一继电器断开且第二继电器闭合。
  12. 根据权利要求1-11中任一项所述的储能系统，其特征在于，所述控制器包括第一控制器和至少两个第二控制器；
    所述第二控制器与所述电池包一一对应连接；
    所述第二控制器，用于获取对应的所述电池包的第二参数值，并将所述第二参数值发送给所述第一控制器；
    所述第一控制器，用于利用所有所述电池包的第二参数值，确定所有所述电池包的第一参数值，当所述电池簇充电时，确定第一参数值大于或等于第一预设参数值的电池包为待旁路电池包，以及当所述电池簇放电时，确定第一参数值小于或等于第二预设参数值的电池包为待旁路电池包；然后向所述第二控制器发送控制指令；所述控制指令，用于指示对应的所述第二控制器控制所述旁路电路旁路所述待旁路电池包。
  13. 根据权利要求12所述的储能系统，其特征在于，所述第二参数值包括电池包的总容量、能量状态SOE值和健康状态SOH值，所述第一参数值为荷电状态SOC值。
  14. 根据权利要求1-11中任一项所述的储能系统，其特征在于，所述控制器包括第一控制器和至少两个第二控制器；
    所述第二控制器与所述电池包一一对应连接；
    所述第二控制器，用于获取对应的所述电池包的第一参数值，并将所述第一参数值发送给所述第一控制器；
    所述第一控制器，用于当所述电池簇充电时，确定第一参数值大于或等于第一预设参数值的电池包为待旁路电池包，以及当所述电池簇放电时，确定第一参数值小于或等于第二预设参数值的电池包为待旁路电池包；然后向所述第二控制器发送控制指令；所述控制指令，用于指示对应的所述第二控制器控制所述旁路电路旁路所述待旁路电池包。
  15. 根据权利要求14所述的储能系统，其特征在于，所述第一参数值为电压值或者荷电状态SOC值。
  16. 一种储能系统的控制方法，其特征在于，所述储能系统的每个电池簇包括至少两个串联连接的储能模组，每个所述储能模组均包括一个旁路电路和一个电池包，每个所述电池包包括多个电池，所述方法包括：
    根据各所述电池包的第一参数值，控制各所述旁路电路，以使各所述电池包的电量均衡。
  17. 根据权利要求16所述的储能系统的控制方法，其特征在于，所述根据各所述电池包的第一参数值，控制各所述旁路电路，具体包括：
    当所述电池簇充电时，控制各所述旁路电路以旁路第一参数值大于或等于第一预设参数值的电池包；
    当所述电池簇放电时，控制各所述旁路电路以旁路第一参数值小于或等于第二预设参数值的电池包。
  18. 根据权利要求17所述的储能系统的控制方法，其特征在于，所述当所述电池簇充电时，控制各所述旁路电路以旁路第一参数值大于或等于第一预设参数值的电池包，具体包括：
    当所述电池簇充电时，依次旁路第一参数值大于或等于所述第一预设参数值的电池包，直至仅剩余一个电池包未被旁路；
    所述当所述电池簇放电时，控制各所述旁路电路以旁路第一参数值小于或等于第二预设参数值的电池包，具体包括：
    当所述电池簇放电时，依次旁路第一参数值小于或等于所述第二预设参数值的电池包，直至仅剩余一个电池包未被旁路。
  19. 根据权利要求18所述的储能系统的控制方法，其特征在于，所述方法还包括：
    当所述电池簇充电时，当仅剩余的一个电池包的第一参数值大于或等于第一预设参数值时，控制各所述旁路电路以使被旁路的电池包重新接入所述电池簇；
    当所述电池簇放电时，当仅剩余的一个电池包的第一参数值小于或等于第二预设参数值时，控制各所述旁路电路以使被旁路的电池包重新接入所述电池簇。
  20. 根据权利要求16-19中任一项所述的储能系统的控制方法，其特征在于，所述方法还包括：
    在旁路所述电池包或接入所述电池包前，控制与所述电池簇的输出端连接的直流/直流 变换电路停止工作，所述直流/直流变换电路的第一端连接所述电池簇的输出端；
    当完成对所述电池包的旁路或接入后，控制所述直流/直流变换电路的第一端的电压等于所述电池簇的输出电压，然后控制所述直流/直流变换电路开始工作。
  21. 根据权利要求16-20中任一项所述的储能系统的控制方法，其特征在于，所述方法还包括：
    获取所有所述电池包对应的第二参数值；
    利用所有所述电池包对应的第二参数值，确定所有所述电池包的第一参数值。
  22. 根据权利要求21所述的储能系统的控制方法，其特征在于，所述第二参数值包括电池包的总容量、能量状态SOE值和健康状态SOH值，所述第一参数值为荷电状态SOC值。
  23. 根据权利要求16-20中任一项所述的储能系统的控制方法，其特征在于，所述第一参数值为电压值或者荷电状态SOC值。
  24. 一种光伏发电系统，其特征在于，所述光伏发电系统包括权利要求1-15中任一项所述的储能系统，还包括光伏发电端；
    所述光伏发电端的输出端用于连接交流电网；
    所述光伏发电端用于利用光能产生交流电。
  25. 一种光伏发电系统，其特征在于，所述光伏发电系统包括权利要求1-15中任一项所述的储能系统，还包括多个光伏组件；
    所述光伏组件，用于利用光能产生直流电以为所述电池簇充电。
PCT/CN2021/086070 2021-04-09 2021-04-09 一种储能系统、储能系统的控制方法及光伏发电系统 WO2022213338A1 (zh)

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