CN113629764A - Charge-discharge control method and application device thereof - Google Patents

Charge-discharge control method and application device thereof Download PDF

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Publication number
CN113629764A
CN113629764A CN202110920267.2A CN202110920267A CN113629764A CN 113629764 A CN113629764 A CN 113629764A CN 202110920267 A CN202110920267 A CN 202110920267A CN 113629764 A CN113629764 A CN 113629764A
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energy storage
charge
power
storage branch
discharge
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范冬冬
周旭东
吴晓磊
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Sunshine Samsung Hefei Energy Storage Power Supply Co ltd
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Sunshine Samsung Hefei Energy Storage Power Supply Co ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/10—Parallel operation of dc sources
    • 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
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/14—Balancing the load in a network
    • 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
    • H02J7/00032—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries characterised by data exchange
    • H02J7/00036—Charger exchanging data with battery
    • 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
    • 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
    • H02J7/0068—Battery or charger load switching, e.g. concurrent charging and load supply
    • 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
    • H02J7/34—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
    • 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
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Abstract

The invention provides a charge-discharge control method and an application device thereof, which are applied to the technical field of power supply, the method is applied to an energy storage system which comprises a plurality of energy storage branches and is connected with an inverter, after a total power correction value of the energy storage system and basic charge-discharge power of each energy storage branch in a previous control period are obtained, the total power correction value is distributed among the energy storage branches on the basis of the basic charge-discharge power of each energy storage branch, further, reference charge-discharge power of each energy storage branch is obtained, and charge-discharge of the corresponding energy storage branch is controlled on the basis of each reference charge-discharge power. The total power correction value to be distributed in the method is the difference value between the target operation power and the actual operation power of the inverter in the current control period, and is far smaller than the target operation power of the current control period, so that the power change corresponding to each energy storage branch is smaller, the possibility of exceeding the charging and discharging power limiting value of the energy storage branch is reduced, and the stability and the reliability of the system operation are ensured.

Description

Charge-discharge control method and application device thereof
Technical Field
The invention relates to the technical field of power supply, in particular to a charge and discharge control method and an application device thereof.
Background
Referring to fig. 1, fig. 1 is a schematic structural diagram of an optical storage system in the prior art, where the optical storage system includes a photovoltaic system, an energy storage system, an inverter, and a controller, where the energy storage system includes a plurality of energy storage branches, any energy storage branch includes an energy storage battery and a DC/DC converter connected in series, an output end of each energy storage branch and an output end of the photovoltaic system are respectively connected to a DC side of the inverter, an ac side of the inverter is connected to an ac power grid, and the controller is respectively connected to each energy storage branch in the energy storage system to control a charging and discharging process of each energy storage branch.
In practical application, the controller acquires the total power to be distributed of the energy storage system in any control period, then distributes the total power to be distributed in each energy storage branch according to the SOC value of the energy storage battery in each energy storage branch, and controls the charging and discharging processes of the corresponding energy storage branch according to the distribution power corresponding to each energy storage branch.
The inventor researches and discovers that in the charge and discharge control method of the energy storage system in the prior art, the total power to be distributed is distributed among the energy storage branches in each control period, so that the energy storage branches can not effectively respond to a power distribution instruction because the power shared by the energy storage branches is larger than the corresponding amplitude limit value, and further the whole optical storage system can not meet the requirement of practical application.
Disclosure of Invention
The invention provides a charge-discharge control method and an application device thereof, which ensure that the variation quantity of reference charge-discharge power corresponding to each energy storage branch circuit in the current control period is smaller than the basic charge-discharge power of the previous control period, reduce the possibility of exceeding the amplitude limit value corresponding to the energy storage branch circuit, avoid the oscillation of the output voltage and the output power of a photovoltaic system, and ensure the stability and the reliability of the operation of the system.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
in a first aspect, the present invention provides a charge and discharge control method, applied to an energy storage system including a plurality of energy storage branches, where the energy storage system is connected to an inverter, the method including:
acquiring a total power correction value of the energy storage system and basic charge and discharge power of each energy storage branch circuit in a previous control period;
the total power correction value is the difference value between the target operation power and the actual operation power of the inverter in the current control period;
distributing the total power correction value among the energy storage branches on the basis of the basic charge-discharge power of each energy storage branch to obtain the reference charge-discharge power of each energy storage branch;
and controlling the charging and discharging of the corresponding energy storage branch circuit based on each reference charging and discharging power.
Optionally, on the basis of the basic charge and discharge power of each energy storage branch, distributing the total power correction value among the energy storage branches to obtain the reference charge and discharge power of each energy storage branch, including:
acquiring battery state parameters of each energy storage branch;
distributing the total power correction value among the energy storage branches based on the battery state parameters to obtain the power correction value of each energy storage branch;
and respectively calculating the sum of the basic charge-discharge power of each energy storage branch and the corresponding power correction value to obtain the reference charge-discharge power of each energy storage branch.
Optionally, the distributing the total power correction value among the energy storage branches based on the battery state parameters to obtain the power correction value of each energy storage branch includes:
according to the battery state parameters, respectively determining the correction proportion of each energy storage branch circuit;
and respectively calculating the product of the correction proportion of each energy storage branch and the total power correction value to obtain the power correction value of each energy storage branch.
Optionally, the battery state parameter includes an SOC value;
the determining the correction proportion of each energy storage branch according to each battery state parameter includes:
if the total power correction value is larger than zero, respectively determining the correction proportion of each energy storage branch according to the following formula:
Figure BDA0003207147040000021
wherein eta represents the correction proportion of the energy storage branch;
n represents the total number of energy storage branches in the energy storage system, and N is more than 1;
SOCirepresenting the SOC value of the ith energy storage branch, i is equal to [1, N]；
SOCZAnd the sum of the SOC values of all energy storage branches in the energy storage system is represented.
Optionally, the battery state parameter includes an SOC value;
the determining the correction proportion of each energy storage branch according to each battery state parameter includes:
if the total power correction value is smaller than zero, respectively determining the correction proportion of each energy storage branch according to the following formula:
Figure BDA0003207147040000031
wherein eta represents the correction proportion of the energy storage branch;
SOCirepresenting the SOC value of the ith energy storage branch, i is equal to [1, N]N is the total number of the energy storage branches;
SOCZand the sum of the SOC values of all energy storage branches in the energy storage system is represented.
Optionally, the determining, according to the battery state parameters, the correction proportion of each energy storage branch includes:
and if the total power correction value is equal to zero, determining the correction proportion of each energy storage branch circuit to be zero.
Optionally, the controlling charging and discharging of the corresponding energy storage branch circuit based on each of the reference charging and discharging powers includes:
respectively processing the reference charge and discharge power of each energy storage branch according to a preset amplitude limiting rule to obtain a target charge and discharge power of each energy storage branch;
and controlling each energy storage branch circuit to charge and discharge according to the corresponding target charge and discharge power.
Optionally, the processing the reference charge-discharge power of each energy storage branch according to a preset amplitude limiting rule to obtain a target charge-discharge power of each energy storage branch includes:
respectively taking each energy storage branch as a target energy storage branch;
acquiring a battery charging and discharging power threshold value and a DC/DC converter power threshold value corresponding to the target energy storage branch;
and taking the minimum value of the battery charge-discharge power threshold, the DC/DC converter power threshold and the reference charge-discharge power as the target charge-discharge power of the target energy storage branch.
Optionally, the obtaining of the battery charge-discharge power threshold corresponding to the target energy storage branch includes:
acquiring a target SOC value of the target energy storage branch circuit;
inquiring a preset mapping relation, and determining a battery charge-discharge power threshold corresponding to a target SOC value of the target energy storage branch circuit;
and recording the corresponding relation between the SOC value of the energy storage battery and the charging and discharging power threshold value of the battery in the preset mapping relation.
Optionally, the controlling each energy storage branch to perform charging and discharging according to a corresponding target charging and discharging power includes:
respectively judging whether each energy storage branch is in a hot standby state;
stopping the charging and discharging process of the energy storage branch in the hot standby state;
and controlling the energy storage branch circuit which is not in the hot standby state to charge and discharge according to the corresponding target charge and discharge power.
Optionally, the energy storage branch not in the hot standby state is controlled to perform charging and discharging according to the corresponding target charging and discharging power;
converting the target charging and discharging power of the energy storage branch circuit which is not in the hot standby state into charging and discharging current;
and controlling the DC/DC converter in the corresponding energy storage branch circuit which is not in the hot standby state to work according to the charging and discharging current so as to charge and discharge the energy storage battery in the corresponding energy storage branch circuit.
Optionally, the obtaining of the total power correction value of the energy storage system and the basic charge and discharge power of each energy storage branch in the previous control period includes:
judging whether the energy storage system is operated for the first time;
if the operation is carried out for the first time, acquiring the total power to be distributed of the energy storage system;
distributing the total power to be distributed to each energy storage branch according to a preset proportion, and controlling each energy storage branch to charge and discharge;
if the energy storage system does not operate for the first time, acquiring a total power correction value of the energy storage system and basic charge and discharge power of each energy storage branch circuit in a previous control period.
In a second aspect, the present invention provides a controller comprising: a memory and a processor; the memory stores a program adapted to be executed by the processor to implement the charge and discharge control method according to any one of the first aspect of the present invention.
In a third aspect, the present invention provides a power generation system comprising: the energy storage system, the inverter and the controller provided by the second aspect of the invention, wherein,
the energy storage system comprises a plurality of energy storage branches;
each energy storage branch is connected with the direct current side of the inverter respectively;
the alternating current side of the inverter is connected with an alternating current power grid;
the controller is respectively connected with each energy storage branch and the inverter.
Optionally, the power generation system provided by the third aspect of the present invention further includes: a photovoltaic system, wherein,
the photovoltaic system is connected to the dc side of the inverter.
The charge and discharge control method provided by the invention is applied to an energy storage system which comprises a plurality of energy storage branches and is connected with an inverter, after the total power correction value of the energy storage system and the basic charge and discharge power of each energy storage branch in the previous control period are obtained, the total power correction value is distributed among the energy storage branches on the basis of the basic charge and discharge power of each energy storage branch, so that the reference charge and discharge power of each energy storage branch is obtained, and the charge and discharge of the corresponding energy storage branch are controlled on the basis of each reference charge and discharge power. In the charge and discharge control method provided by the invention, the total power correction value to be distributed is the difference value between the target operating power and the actual operating power of the inverter in the current control period, namely the total power correction value is the power variation of the inverter relative to the previous control period and is far smaller than the target operating power of the current control period, so that the power variation corresponding to each energy storage branch is smaller when the power correction value is distributed among the energy storage branches, the possibility of exceeding the charge and discharge power limit value of the energy storage branch is reduced, further, the charge and discharge power variation of the energy storage branches in the current control period is smaller, the oscillation of the voltage and the power of the direct current side of the photovoltaic system can be avoided, and the stability and the reliability of the system operation are ensured.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of a prior art light storage system;
fig. 2 is a flowchart of a charging and discharging control method according to an embodiment of the present invention;
fig. 3 is a flowchart for obtaining the reference charging and discharging power of the energy storage branch according to the embodiment of the present invention;
fig. 4 is a flowchart of another charge and discharge control method according to an embodiment of the present invention;
fig. 5 is a block diagram of a controller according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The charge and discharge control method provided by the embodiment of the invention is applied to an energy storage system comprising a plurality of energy storage branches, the output end of the energy storage system is connected with an alternating current power grid through an inverter, and in a selectable application scene, the charge and discharge control method further comprises a photovoltaic system, and the output end of the photovoltaic system is also connected with the direct current side of the inverter. Specifically, the charge and discharge control method provided in the embodiment of the present invention may be applied to a controller capable of obtaining relevant parameters of the energy storage branches, the inverter, and other devices in the energy storage system, operating a preset control program, and controlling the operating state of each energy storage branch, or may be applied to other controllers in a power supply system including the energy storage system, the photovoltaic system, and the inverter, or may be applied to a server on a network side in some cases. Referring to fig. 1, a process of a charging and discharging control method provided in an embodiment of the present invention may include:
s100, acquiring a total power correction value of the energy storage system and basic charge and discharge power of each energy storage branch in a previous control period.
In practical application, the inverter receives, in a current control period, an expected operating power corresponding to the current control period, where the expected operating power is a target operating power mentioned in this embodiment, and correspondingly, before the inverter performs operating power adjustment, the inverter itself corresponds to an actual operating power after the previous control period is ended, and a difference value between the target operating power and the actual operating power of the inverter is a total power correction value corresponding to the current control period of the inverter mentioned in this embodiment. It is conceivable that the total power correction value is the total power to be distributed that needs to be distributed to the individual energy storage branches in the energy storage system.
Further, the charging and discharging power of each energy storage branch in the energy storage system in the previous control period also needs to be obtained, and of course, the actual charging and discharging power of each energy storage branch before the power adjustment of the current control period can also be understood, and the charging and discharging power is defined as the basic charging and discharging power in the embodiment of the present invention.
And S110, distributing a total power correction value among the energy storage branches on the basis of the basic charge and discharge power of the energy storage branches to obtain the reference charge and discharge power of the energy storage branches.
As mentioned above, the total power correction value is the total power to be distributed, and during specific distribution, the total power correction value needs to be distributed among the energy storage branches on the basis of the basic charge and discharge power of each energy storage branch, so that each energy storage branch shares a part of the total power correction value on the basis of the original basic charge and discharge power.
The embodiment of the invention defines the sum of the basic charge and discharge power of the energy storage branch circuit and the total correction value of partial power shared by the energy storage branch circuit as the reference charge and discharge power. After the charge and discharge power shared by all the energy storage branches is determined, the reference charge and discharge power of each energy storage branch can be obtained.
The specific process of distributing the total power correction value among the energy storage branches will be developed in the following, and will not be described in detail here.
And S120, controlling the charging and discharging of the corresponding energy storage branch circuit based on the reference charging and discharging power.
After the reference charge and discharge power of each energy storage branch is obtained, the corresponding energy storage branch is controlled to be charged and discharged based on the corresponding reference charge and discharge power of each energy storage branch.
As mentioned above, the energy storage branch includes the energy storage battery and the DC/DC converter connected in series, and in practical application, the charging and discharging power thresholds of the energy storage battery in different states are different, and the DC/DC converter also corresponds to its own power threshold, based on which, during the charging and discharging process of the energy storage battery, the actually adopted charging and discharging power cannot be greater than the two thresholds.
Optionally, in order to ensure safe performance of the charging and discharging process of the energy storage battery, during actual control of the energy storage branches for charging and discharging, the reference charging and discharging power of each energy storage branch needs to be processed according to a preset amplitude limiting rule, so as to obtain a target charging and discharging power meeting the actual operation requirement of each energy storage branch, and then each energy storage branch can be controlled to perform charging and discharging according to the corresponding target charging and discharging power.
As described above, the charging and discharging power threshold of the energy storage battery is related to the state of the energy storage battery, and based on this, an embodiment of the present invention provides a preset mapping relationship, where a corresponding relationship between the SOC value of the energy storage battery and the charging and discharging power threshold of the battery is recorded in the preset mapping relationship, when determining the charging and discharging power threshold of the battery of each energy storage branch, each energy storage branch may be used as a target energy storage branch, and after obtaining the SOC value of the target energy storage branch, that is, obtaining the target SOC value, the preset mapping relationship is queried, so as to determine the charging and discharging power threshold of the battery corresponding to the target SOC value.
Further, for a determined energy storage branch, the set power threshold of the DC/DC converter may be known definitely, and on this basis, a battery charging and discharging power threshold corresponding to any energy storage branch, a DC/DC converter power threshold, and the reference charging and discharging power calculated in the foregoing step may be obtained, and the minimum value among the battery charging and discharging power threshold, the DC/DC converter power threshold, and the reference charging and discharging power is used as the target charging and discharging power of the target energy storage branch along with the definition of the target energy storage branch.
Optionally, when each energy storage branch is controlled to operate according to the corresponding target charging and discharging power, whether each energy storage branch is in a hot standby state is judged, if any energy storage branch is in the hot standby state, the charging and discharging process of the energy storage branch is stopped, that is, the power adjustment process cannot be effectively responded, and for the energy storage branches not in the hot standby state, the charging and discharging are performed according to the corresponding target charging and discharging power obtained in the previous step.
It should be noted that the energy storage branches in which the energy storage battery is in a fully charged or empty state are all energy storage branches in a hot standby state.
Further, according to the control process of the DC/DC converter in the prior art, the DC/DC converter generally operates in a constant current mode, and the voltage at two ends of the DC/DC converter is not adjusted in the control process, so that when the energy storage branches are controlled to charge and discharge according to the target charge and discharge power, the target charge and discharge power of the energy storage branches not in the thermal standby state can be converted into charge and discharge current, and then the DC/DC converter in the corresponding energy storage branch not in the thermal standby state is controlled to operate according to the obtained charge and discharge current, so as to charge and discharge the energy storage battery in the corresponding energy storage branch.
In summary, in the charge and discharge control method provided in the embodiment of the present invention, the total power correction value to be allocated is a difference between the target operating power and the actual operating power of the inverter in the current control period, that is, the total power correction value is a power variation of the inverter with respect to the previous control period, which is much smaller than the target operating power of the current control period, so that when the power correction value is allocated among the energy storage branches, the power variation corresponding to each energy storage branch is relatively small, and the possibility of exceeding the charge and discharge power limit value of the energy storage branch is reduced.
Furthermore, before the actual charging and discharging control of the energy storage branch circuit, the state of the energy storage battery can be identified, so that the charging and discharging operation of the energy storage battery in a hot standby state is avoided, and the safety of the charging process is facilitated.
The process of distributing the total power correction value among the energy storage branches is described below, and referring to fig. 2, fig. 2 is a flowchart of the process of distributing the total power correction value, and the process may include:
and S200, acquiring the battery state parameters of each energy storage branch.
Optionally, in this embodiment, the battery state parameter of the energy storage branch includes an SOC value of the energy storage battery, and of course, other parameters capable of representing the operation state of the energy storage battery and the electric quantity of the battery may also be selected, and the parameters also belong to the scope of protection of the present invention on the premise of not exceeding the scope of the core idea of the present invention.
And S210, distributing the total power correction value among the energy storage branches based on the battery state parameters to obtain the power correction value of each energy storage branch.
Optionally, when the operation in this step is implemented, the operation may be roughly divided into two steps, and the correction proportion of each energy storage branch is determined according to the state parameter of each battery, and then the product of the correction proportion of each energy storage branch and the total power correction value is calculated, so that the power correction value of each energy storage branch can be obtained.
Since the operation of each energy storage branch is the same, the following process of determining the correction ratio is detailed by taking any energy storage branch as an example.
Firstly, determining the correction proportion of the energy storage branch circuit according to the battery state parameter. According to the actual operation condition of the power supply system, the load power is inevitably fluctuated, so that three conditions of increasing, reducing and maintaining the operation power of the inverter are caused, correspondingly, the total power correction value of the inverter is increased, reduced and maintained, and different correction proportion determining methods are provided according to different conditions of the total power correction value.
Specifically, if the total power correction value is greater than zero, it indicates that the power adjustment direction should be to increase the charging power or decrease the discharging power of the energy storage branch, and in this power adjustment direction, the correction ratio of the energy storage branch needs to be determined according to the following formula:
Figure BDA0003207147040000091
wherein eta represents the correction proportion of the energy storage branch;
n represents the total number of energy storage branches in the energy storage system, and N is more than 1;
SOCirepresenting the SOC value of the ith energy storage branch, i is equal to [1, N]；
SOCZAnd the sum of the SOC values of all energy storage branches in the energy storage system is represented.
Meanwhile, according to the formula, when the energy storage branches are transversely compared, the correction proportion corresponding to the energy storage branch with the large SOC value is smaller, correspondingly, the shared power is smaller, and the balance of the SOC values among the energy storage branches is facilitated.
If the total power correction value is less than zero, it indicates that the power adjustment direction should be to decrease the charging power or increase the discharging power of the energy storage branch, and in this power adjustment direction, the correction ratio of the energy storage branch can be determined according to the following formula:
Figure BDA0003207147040000101
wherein eta represents the correction proportion of the energy storage branch;
SOCirepresenting the SOC value of the ith energy storage branch, i is equal to [1, N]N is the total number of the energy storage branches;
SOCZand the sum of the SOC values of all energy storage branches in the energy storage system is represented.
Based on the above calculation formula, it can also be seen that, when the energy storage branches are compared transversely, the correction proportion corresponding to the energy storage branch with a large SOC value is larger, and the amplitude of the corresponding energy storage branch for reducing the charging power or increasing the discharging power is larger, which is helpful for establishing the balance of the SOC among the energy storage branches.
Further, if the total power correction value is equal to zero, it indicates that the target operating power of the inverter in the current control period is consistent with the actual operating power of the inverter, and no adjustment is needed.
And S220, respectively calculating the sum of the basic charge and discharge power of each energy storage branch and the corresponding power correction value to obtain the reference charge and discharge power of each energy storage branch.
And for each energy storage branch, after the power correction value of the energy storage branch is obtained, the sum of the power correction value and the basic charge and discharge power of the energy storage branch is obtained, namely the reference charge and discharge power of the energy storage branch.
It can be seen from the above process of determining the reference charging and discharging power of the energy storage branches, that in the charging and discharging control method provided by this embodiment, when the charging and discharging power that needs to be shared by each energy storage branch is adjusted, the proportion that the energy storage branches need to share the power is determined based on the SOC value of the energy storage branch, so that the variation of the charging and discharging power matches with the SOC value of itself, and the SOC value balance among the energy storage branches is facilitated.
Furthermore, the charging and discharging power of the energy storage branch circuit in the current control period is obtained after small adjustment based on the basic charging and discharging power, so that sudden change of the charging and discharging power of the energy storage branch circuit can be effectively avoided, the requirement on the performance of a DC/DC converter in the energy storage branch circuit is reduced, and voltage oscillation and power oscillation of a photovoltaic system caused by large change of the charging and discharging power can be effectively avoided.
Optionally, referring to fig. 4, fig. 4 is a flowchart of another charging and discharging control method provided in an embodiment of the present invention, and on the basis of the embodiment shown in fig. 2, the flowchart of the charging and discharging control method provided in this embodiment further includes:
and S300, judging whether the energy storage system is operated for the first time, if so, executing S310, and if not, executing S100.
The specific implementation method for judging whether the energy storage system is operated for the first time can be implemented by referring to the prior art, and the invention is not limited to this.
In the case where it is determined that the energy storage system is operated for the first time, S310 is performed, and on the contrary, if it is determined that the energy storage system is not operated for the first time, S100 and the subsequent steps are performed.
And S310, acquiring the total power to be distributed of the energy storage system.
It is conceivable that, in the case where the energy storage system is operated for the first time, the total power correction value mentioned in the foregoing description cannot be calculated without the previous control period, and in such a case, the total power to be distributed of the energy storage system needs to be obtained in this embodiment. It should be noted that the actual total power to be allocated here may be the same as the target operating power of the inverter, or may be different from the target operating power of the inverter, and mainly depends on the operating condition of the photovoltaic system connected to the inverter, and if the inverter is not connected to the photovoltaic system or the connected photovoltaic system does not have power output, in this case, the target operating power of the inverter is the total power to be allocated of the energy storage system.
And S320, distributing the total power to be distributed to each energy storage branch according to a preset proportion, and controlling each energy storage branch to charge and discharge.
In practical application, the preset proportion corresponding to each energy storage branch circuit can be set based on the rated capacity or other parameters of the energy storage battery in the energy storage branch circuit, and the specific selection of the preset proportion is not limited. Under the condition that the energy storage systems select the same energy storage branch, the total power to be distributed can be equally distributed to each energy storage branch.
For the case that the energy storage system is not operated for the first time, the control may be performed according to S100 and subsequent steps, and the specific control process may be implemented with reference to the embodiment shown in fig. 2, which is not described herein again.
Optionally, referring to fig. 5, fig. 5 is a block diagram of a structure of a controller according to an embodiment of the present invention, as shown in fig. 5, the controller may include: at least one processor 100, at least one communication interface 200, at least one memory 300, and at least one communication bus 400;
in the embodiment of the present invention, the number of the processor 100, the communication interface 200, the memory 300, and the communication bus 400 is at least one, and the processor 100, the communication interface 200, and the memory 300 complete the communication with each other through the communication bus 400; it is clear that the communication connections shown by the processor 100, the communication interface 200, the memory 300 and the communication bus 400 shown in fig. 5 are merely optional;
optionally, the communication interface 200 may be an interface of a communication module, such as an interface adapted to a vehicle-mounted OBD interface or other CAN network interfaces;
the processor 100 may be a central processing unit CPU or an application Specific Integrated circuit asic or one or more Integrated circuits configured to implement embodiments of the present invention.
The memory 300, which stores application programs, may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.
The processor 100 is specifically configured to execute an application program in the memory to implement any of the embodiments of the charging and discharging control method described above.
Optionally, an embodiment of the present invention further provides a power generation system, including: the energy storage system, the inverter and the controller provided in the above embodiments, wherein,
the energy storage system comprises a plurality of energy storage branches;
each energy storage branch is connected with the direct current side of the inverter respectively;
the alternating current side of the inverter is connected with an alternating current power grid;
the controller is respectively connected with each energy storage branch and the inverter.
Optionally, the power generation system provided in this embodiment further includes: a photovoltaic system, wherein,
the photovoltaic system is connected to the dc side of the inverter.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (15)

1. A charge and discharge control method is applied to an energy storage system comprising a plurality of energy storage branches, and the energy storage system is connected with an inverter, and the method comprises the following steps:
acquiring a total power correction value of the energy storage system and basic charge and discharge power of each energy storage branch circuit in a previous control period;
the total power correction value is the difference value between the target operation power and the actual operation power of the inverter in the current control period;
distributing the total power correction value among the energy storage branches on the basis of the basic charge-discharge power of each energy storage branch to obtain the reference charge-discharge power of each energy storage branch;
and controlling the charging and discharging of the corresponding energy storage branch circuit based on each reference charging and discharging power.
2. The charge-discharge control method according to claim 1, wherein the distributing the total power correction value among the energy storage branches on the basis of the basic charge-discharge power of each energy storage branch to obtain the reference charge-discharge power of each energy storage branch comprises:
acquiring battery state parameters of each energy storage branch;
distributing the total power correction value among the energy storage branches based on the battery state parameters to obtain the power correction value of each energy storage branch;
and respectively calculating the sum of the basic charge-discharge power of each energy storage branch and the corresponding power correction value to obtain the reference charge-discharge power of each energy storage branch.
3. The charge and discharge control method according to claim 2, wherein the distributing the total power correction value among the energy storage branches based on the battery state parameters to obtain the power correction value of each energy storage branch comprises:
according to the battery state parameters, respectively determining the correction proportion of each energy storage branch circuit;
and respectively calculating the product of the correction proportion of each energy storage branch and the total power correction value to obtain the power correction value of each energy storage branch.
4. The charge-discharge control method according to claim 3, wherein the battery state parameter includes an SOC value;
the determining the correction proportion of each energy storage branch according to each battery state parameter includes:
if the total power correction value is larger than zero, respectively determining the correction proportion of each energy storage branch according to the following formula:
Figure FDA0003207147030000021
wherein eta represents the correction proportion of the energy storage branch;
n represents the total number of energy storage branches in the energy storage system, and N is more than 1;
SOCirepresenting the SOC value of the ith energy storage branch, i is equal to [1, N]；
SOCZAnd the sum of the SOC values of all energy storage branches in the energy storage system is represented.
5. The charge-discharge control method according to claim 3, wherein the battery state parameter includes an SOC value;
the determining the correction proportion of each energy storage branch according to each battery state parameter includes:
if the total power correction value is smaller than zero, respectively determining the correction proportion of each energy storage branch according to the following formula:
Figure FDA0003207147030000022
wherein eta represents the correction proportion of the energy storage branch;
SOCirepresenting the SOC value of the ith energy storage branch, i is equal to [1, N]N is the total number of the energy storage branches;
SOCZand the sum of the SOC values of all energy storage branches in the energy storage system is represented.
6. The charge and discharge control method according to claim 3, wherein the determining the correction proportion of each energy storage branch circuit according to each battery state parameter comprises:
and if the total power correction value is equal to zero, determining the correction proportion of each energy storage branch circuit to be zero.
7. The charge and discharge control method according to claim 1, wherein the controlling of charging and discharging of the corresponding energy storage branch based on each of the reference charge and discharge powers comprises:
respectively processing the reference charge and discharge power of each energy storage branch according to a preset amplitude limiting rule to obtain a target charge and discharge power of each energy storage branch;
and controlling each energy storage branch circuit to charge and discharge according to the corresponding target charge and discharge power.
8. The charge and discharge control method according to claim 7, wherein the processing the reference charge and discharge power of each energy storage branch according to a preset amplitude limiting rule to obtain the target charge and discharge power of each energy storage branch comprises:
respectively taking each energy storage branch as a target energy storage branch;
acquiring a battery charging and discharging power threshold value and a DC/DC converter power threshold value corresponding to the target energy storage branch;
and taking the minimum value of the battery charge-discharge power threshold, the DC/DC converter power threshold and the reference charge-discharge power as the target charge-discharge power of the target energy storage branch.
9. The charge and discharge control method according to claim 8, wherein the obtaining of the battery charge and discharge power threshold corresponding to the target energy storage branch comprises:
acquiring a target SOC value of the target energy storage branch circuit;
inquiring a preset mapping relation, and determining a battery charge-discharge power threshold corresponding to a target SOC value of the target energy storage branch circuit;
and recording the corresponding relation between the SOC value of the energy storage battery and the charging and discharging power threshold value of the battery in the preset mapping relation.
10. The charge and discharge control method according to claim 7, wherein the controlling of the charge and discharge of each energy storage branch circuit according to the corresponding target charge and discharge power comprises:
respectively judging whether each energy storage branch is in a hot standby state;
stopping the charging and discharging process of the energy storage branch in the hot standby state;
and controlling the energy storage branch circuit which is not in the hot standby state to charge and discharge according to the corresponding target charge and discharge power.
11. The charge and discharge control method according to claim 10, wherein the energy storage branches which are not in the hot standby state are controlled to be charged and discharged according to the corresponding target charge and discharge power;
converting the target charging and discharging power of the energy storage branch circuit which is not in the hot standby state into charging and discharging current;
and controlling the DC/DC converter in the corresponding energy storage branch circuit which is not in the hot standby state to work according to the charging and discharging current so as to charge and discharge the energy storage battery in the corresponding energy storage branch circuit.
12. The charge-discharge control method according to any one of claims 1-11, wherein the obtaining of the total power correction value of the energy storage system and the basic charge-discharge power of each energy storage branch circuit in a previous control period comprises:
judging whether the energy storage system is operated for the first time;
if the operation is carried out for the first time, acquiring the total power to be distributed of the energy storage system;
distributing the total power to be distributed to each energy storage branch according to a preset proportion, and controlling each energy storage branch to charge and discharge;
if the energy storage system does not operate for the first time, acquiring a total power correction value of the energy storage system and basic charge and discharge power of each energy storage branch circuit in a previous control period.
13. A controller, comprising: a memory and a processor; the memory stores a program adapted to be executed by the processor to implement the charge and discharge control method according to any one of claims 1 to 12.
14. A power generation system, comprising: the energy storage system, the inverter, and the controller of claim 13,
the energy storage system comprises a plurality of energy storage branches;
each energy storage branch is connected with the direct current side of the inverter respectively;
the alternating current side of the inverter is connected with an alternating current power grid;
the controller is respectively connected with each energy storage branch and the inverter.
15. The power generation system of claim 14, further comprising: a photovoltaic system, wherein,
the photovoltaic system is connected to the dc side of the inverter.
CN202110920267.2A 2021-08-11 2021-08-11 Charge-discharge control method and application device thereof Pending CN113629764A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114884165A (en) * 2022-05-11 2022-08-09 杭州华塑科技股份有限公司 Current equalizing method and device for energy storage equipment

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114884165A (en) * 2022-05-11 2022-08-09 杭州华塑科技股份有限公司 Current equalizing method and device for energy storage equipment
CN114884165B (en) * 2022-05-11 2023-09-05 杭州华塑科技股份有限公司 Flow equalizing method and device for energy storage equipment

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