CN115047277A - Energy storage system and branch anomaly detection method thereof - Google Patents
Energy storage system and branch anomaly detection method thereof Download PDFInfo
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- CN115047277A CN115047277A CN202210734055.XA CN202210734055A CN115047277A CN 115047277 A CN115047277 A CN 115047277A CN 202210734055 A CN202210734055 A CN 202210734055A CN 115047277 A CN115047277 A CN 115047277A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
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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
- H02J3/28—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
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
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Abstract
The application provides an energy storage system and a branch circuit abnormity detection method thereof. In the branch abnormality detection method of the energy storage system, the branch current and the branch voltage of each branch are combined when the abnormal branch is determined, so that the accuracy rate of determining the abnormal branch is improved, and the method can be used for realizing the abnormality detection of each branch in the energy storage inverter, namely the branch abnormality detection method of the energy storage system can realize the abnormality detection of each branch in the energy storage inverter; in addition, the branch anomaly detection method of the energy storage system can realize anomaly detection of each branch in the energy storage inverter only through software, so that additional hardware and matched hardware circuits do not need to be added in the energy storage inverter, and the branch anomaly detection cost of the energy storage inverter can be reduced.
Description
Technical Field
The invention relates to the technical field of automatic control, in particular to an energy storage system and a branch circuit abnormity detection method thereof.
Background
At present, a high-power energy storage inverter in an energy storage system mostly adopts a direct-current side multi-branch structure design, and the design specifically comprises the following steps: the direct current side of the energy storage inverter comprises at least two pairs of connecting ports, each pair of connecting ports is connected with a direct current bus through a branch, the direct current bus is connected with the direct current side of a DCAC conversion module in the energy storage inverter, and each branch is provided with a branch fuse.
Under normal conditions, microswitch feedback is configured in each branch circuit, so that the corresponding branch circuit with abnormal branch circuit fuse wires can be detected in time; however, if each branch is configured with the microswitch feedback, the branch abnormality detection cost of the energy storage inverter is increased, and meanwhile, the overall cost of the energy storage inverter is increased, and in addition, the space in the cabinet is occupied, the design difficulty is increased, the feedback signal sampling port in the circuit is increased, and the circuit complexity is increased.
Therefore, how to reduce the branch anomaly detection cost of the energy storage inverter is an urgent technical problem to be solved.
Disclosure of Invention
In view of this, the present invention provides an energy storage system and a branch anomaly detection method thereof, so as to reduce the branch anomaly detection cost of an energy storage inverter.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
one aspect of the present application provides a method for detecting branch anomaly of an energy storage system, where an energy storage inverter in the energy storage system includes at least two branches, and the branches are indirectly connected to one-to-one corresponding battery clusters in the energy storage system; the branch anomaly detection method of the energy storage system comprises the following steps:
judging whether the running power of the energy storage inverter is greater than or equal to a preset power;
if the operating power of the energy storage inverter is greater than or equal to the preset power, determining an abnormal branch in each branch by combining the branch current and the branch voltage of each branch; the abnormal branch is the branch with the abnormality;
and after the abnormal branches are determined, disconnecting each abnormal branch from the corresponding battery cluster.
Optionally, determining an abnormal branch in each branch by combining the branch current and the branch voltage of each branch includes:
according to the branch current of each branch, determining a suspected abnormal branch in each branch; the suspected abnormal branch is the branch suspected to be abnormal;
and after the suspected abnormal branches are determined, determining the abnormal branches in each suspected abnormal branch according to the branch voltage of each branch.
Optionally, determining a suspected abnormal branch in each branch according to the branch current of each branch includes:
judging whether the branch current of each branch is greater than or equal to a preset current or not;
if the branch current of at least one branch is smaller than the preset current, the branch of which the branch current is smaller than the preset current is determined as the suspected abnormal branch.
Optionally, if in the energy storage system, the branch circuits are connected to the corresponding battery clusters through the switch boxes in one-to-one correspondence, determining the abnormal branch circuit in each suspected abnormal branch circuit according to the branch circuit voltage of each branch circuit, including:
after a first preset time, judging whether absolute values of differences between branch voltages of the suspected abnormal branches and bus voltages of a direct current bus in the energy storage inverter are all smaller than or equal to a first preset difference;
if the absolute value of the difference between the branch voltage of at least one suspected abnormal branch and the bus voltage is larger than the first preset difference, determining the suspected abnormal branch of which the absolute value of the difference between the branch voltage and the bus voltage is larger than the first preset difference as the abnormal branch.
Optionally, if in the energy storage system, the branch circuits are connected to the corresponding battery clusters through the dc converters in one-to-one correspondence, determining the abnormal branch circuit in each suspected abnormal branch circuit according to the branch circuit voltage of each branch circuit, including:
controlling the direct current converter corresponding to the suspected abnormal branch to stop or stand by;
judging whether the absolute values of the difference values between the branch voltage of each suspected abnormal branch and the bus voltage of the direct-current bus in the energy storage inverter are smaller than or equal to a second preset difference value;
if the absolute value of the difference between the branch voltage of at least one suspected abnormal branch and the bus voltage is larger than the second preset difference, determining the suspected abnormal branch with the absolute value of the difference between the branch voltage and the bus voltage larger than the second preset difference as the abnormal branch.
Optionally, controlling the dc converter to be in standby includes:
controlling a DCDC conversion module in the DC converter to stop power conversion, and closing at least one DC switch in the DC converter;
controlling the DC converter to shut down, comprising:
and controlling the DCDC conversion module to stop power conversion, and opening at least one direct current switch.
Optionally, the energy storage inverter further includes: the DC side is respectively connected with the DCAC conversion module of each branch circuit through a DC bus; after the operating power of the energy storage inverter is judged to be smaller than the preset power, the method further comprises the following steps:
judging whether the DCAC conversion module is in standby state and/or whether each branch is respectively communicated with the corresponding battery cluster;
if the DCAC conversion module is in standby and/or each branch is respectively communicated with the corresponding battery cluster, judging whether the absolute values of the difference values between the branch voltage of each branch and the bus voltage of the direct-current bus in the energy storage inverter are smaller than or equal to a third preset difference value;
if the absolute value of the difference value between the branch voltage of at least one branch and the bus voltage is greater than the third preset difference value, determining the branch with the absolute value of the difference value between the branch voltage and the bus voltage greater than the third preset difference value as an abnormal branch;
and after the abnormal branch is determined, disconnecting the abnormal branch from the corresponding battery cluster.
Optionally, the determining whether the DCAC conversion module is in standby includes:
judging whether a main circuit in the DCAC conversion module stops power conversion or not, and whether a direct current side switch and an alternating current side switch in the DCAC conversion module are both closed or not;
and if the main circuit stops power conversion and the direct current side switch and the alternating current side switch are both closed, judging that the DCAC conversion module is in a standby state.
Optionally, the judgment on whether each branch is respectively communicated with the corresponding battery cluster is only applicable to the energy storage systems in which the branches are connected with the corresponding battery clusters through one-to-one corresponding switch boxes;
judging whether each branch is respectively communicated with the corresponding battery cluster or not, comprising the following steps:
judging whether the switches in the switch boxes corresponding to the branches are closed or not;
and if the switches in the switch boxes corresponding to the branches are closed, determining that the branches are respectively communicated with the corresponding battery clusters.
Optionally, if in the energy storage system, the branch is connected to the corresponding battery cluster through the switch boxes corresponding to one, the disconnection between the abnormal branch and the corresponding battery cluster includes:
and controlling the switch in the switch box corresponding to the abnormal branch to be switched off.
Optionally, if, in the energy storage system, the branch is connected to the corresponding battery cluster through the one-to-one dc converters, the disconnecting between the abnormal branch and the corresponding battery cluster includes:
and controlling the direct current converter corresponding to the abnormal branch circuit to stop.
Optionally, after determining that the absolute values of the differences between the branch voltages of the target branches and the bus voltages of the dc buses in the energy storage inverter are all less than or equal to the corresponding preset differences, the method further includes:
judging whether the absolute values of the difference values between the branch voltage of each target branch and the bus voltage are less than or equal to corresponding preset difference values within second preset time; the target branch is a suspected abnormal branch or the branch;
if the absolute value of the difference between the branch voltage of each target branch and the bus voltage is less than or equal to the corresponding preset difference within the second preset time, determining that each target branch is not abnormal;
and if the absolute values of the difference values between the branch voltage of each target branch and the bus voltage are not less than or equal to the corresponding preset difference value within the second preset time, returning to execute the step of judging whether the absolute values of the difference values between the branch voltage of each target branch and the bus voltage of the direct-current bus in the energy storage inverter are less than or equal to the corresponding preset difference value.
Optionally, if, in the energy storage system, the branches are connected to the corresponding battery clusters through the dc converters corresponding to one, after determining that each of the target branches is not abnormal according to the voltage difference, the method further includes:
and controlling the starting operation of each direct current converter corresponding to each target branch.
Optionally, controlling the dc converter to start up includes:
and the DCDC conversion module in the DC converter performs power conversion and controls the closing of a DC switch in the DC converter.
Another aspect of the present application provides an energy storage system, including: the system comprises an energy storage inverter, a controller, at least two battery clusters and at least two switching devices; the energy storage inverter includes: at least two branches; wherein:
one side of each branch is connected with the corresponding battery clusters through the corresponding switch devices;
the energy storage inverter and each switching device are controlled by the controller, and the controller is used for executing the branch circuit abnormality detection method of the energy storage system according to any one of the previous aspects of the application.
Optionally, each of the switching devices is a switch box or a dc converter.
Optionally, the switch box includes: a fuse and a switch connected in series with each other.
Optionally, the dc converter includes: DCDC conversion module and at least one direct current switch that mutual series connection.
Optionally, the energy storage inverter further includes: a DC bus and a DCAC conversion module; wherein:
the other side of each branch circuit is connected with the direct current side of the DCAC conversion module through the direct current bus;
the alternating current side of the DCAC conversion module is connected with the alternating current side of the energy storage inverter;
the DCAC conversion module is controlled by the controller.
Optionally, the DCAC conversion module includes: the main circuit, the direct current side switch and the alternating current side switch; wherein:
the direct current side of the main circuit is connected with the direct current side of the DCAC conversion module through the direct current side switch;
the alternating current side of the main circuit is connected with the alternating current side of the DCAC conversion module through the alternating current side switch;
the direct current side switch and the alternating current side switch are controlled by the controller.
According to the technical scheme, the invention provides a branch anomaly detection method of an energy storage system. In the branch abnormality detection method of the energy storage system, the branch current and the branch voltage of each branch are combined when the abnormal branch is determined, so that the accuracy rate of determining the abnormal branch is improved, and the method can be used for realizing the abnormality detection of each branch in the energy storage inverter, namely the branch abnormality detection method of the energy storage system can realize the abnormality detection of each branch in the energy storage inverter; in addition, the branch anomaly detection method of the energy storage system can realize anomaly detection of each branch in the energy storage inverter only through software, so that additional hardware and matched hardware circuits do not need to be added in the energy storage inverter, and the branch anomaly detection cost of the energy storage inverter can be reduced.
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 embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 to fig. 3 are schematic flow diagrams of three embodiments of a method for detecting a branch anomaly of an energy storage system according to an embodiment of the present disclosure;
fig. 4 to fig. 8 are schematic flowcharts of five implementation manners of step S220 provided in the embodiment of the present application;
fig. 9 is a schematic flowchart of an implementation manner after determining that the operating power of the energy storage inverter is smaller than the preset power according to an embodiment of the present disclosure;
fig. 10 is a schematic flowchart illustrating an implementation manner of determining whether a DCAC conversion module is in a standby state according to an embodiment of the present application;
fig. 11 is a schematic flowchart of an implementation manner of determining whether a dc-side switch and an ac-side switch in a DCAC conversion module are both closed according to an embodiment of the present disclosure;
fig. 12 is a schematic flowchart of another implementation manner after determining that the operating power of the energy storage inverter is smaller than the preset power, according to an embodiment of the present disclosure;
fig. 13 to fig. 16 are schematic structural diagrams of four embodiments of an energy storage system according to an embodiment of the present application.
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.
In this application, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
In order to reduce the branch anomaly detection cost of the energy storage inverter, another embodiment of the present application provides a branch anomaly detection method for an energy storage system, in which the energy storage inverter includes at least two branches, and each branch is indirectly connected to a one-to-one corresponding battery cluster in the energy storage system.
In practical application, each branch can be connected with a corresponding battery cluster through a switch box in one-to-one correspondence, and the energy storage system adopting the structure is called a single-stage mode energy storage system; each branch can also be connected with a corresponding battery cluster through a direct current converter in one-to-one correspondence, and the energy storage system adopting the structure is called a two-stage mode energy storage system; it is not specifically limited herein, and may be within the scope of the present application depending on the specific circumstances.
The specific flow of the method for detecting the branch abnormality of the energy storage system is shown in fig. 1, and specifically comprises the following steps:
and S110, judging whether the running power of the energy storage inverter is greater than or equal to the preset power.
If the operating power of the energy storage inverter is greater than or equal to the preset power, step S120 is executed.
The preset power is equal to the product of the division value and the number of the branches when the controller detects the branch operating power of each branch; therefore, when the operating power of the energy storage inverter is greater than the preset power, even if the branch operating power of the branch is changed from the division value to zero, the controller can still detect the branch operating power, and therefore misjudgment is avoided.
For example, assuming that the energy storage inverter includes two branches, the preset power is equal to 20W; when the branch operating power of each branch is 10w, if a branch fuse on a certain branch fails, that is, if the branch has an open-circuit fault, the branch current on the branch becomes 0, and the branch operating power of the branch is 0, and since the division value of the controller when detecting the branch operating power of each branch is 10w, the controller can detect that the branch operating power of the branch has changed.
In practical applications, the preset power may be set according to specific situations, and is not specifically limited herein and is within the scope of the present application.
And S120, determining abnormal branches in the branches by combining the branch current and the branch voltage of each branch.
Wherein, the abnormal branch is the branch with abnormality; in practical application, each branch is provided with a branch fuse, so that the branch abnormality is specifically as follows: an abnormality, such as a fuse rupture, occurs in the branch fuse in the branch.
When each branch circuit has a fault, the branch circuit current and the branch circuit voltage of each branch circuit can change, so that the abnormal branch circuit can be determined by utilizing the branch circuit current or the branch circuit voltage of each branch circuit, but the accuracy rate is lower at the moment; and after the two are combined, the abnormal branch is determined, so that the accuracy of determining the abnormal branch can be greatly improved, and the abnormal detection of each branch in the energy storage inverter can be realized by using the method.
And S130, after the abnormal branches are determined, disconnecting the abnormal branches from the corresponding battery clusters.
If the energy storage system is a single-stage mode energy storage system, the specific implementation mode of disconnecting the abnormal branches and the corresponding battery clusters is as follows: and controlling the switch in the switch box corresponding to the abnormal branch to be switched off.
If the energy storage system is a two-stage mode energy storage system, the specific implementation mode of disconnecting the connection between each abnormal branch and the corresponding battery cluster is as follows: and controlling the direct current converter corresponding to the abnormal branch circuit to stop.
It should be noted that the specific implementation of controlling the dc converter to stop will be described in detail in the following embodiments, and will not be described herein again.
Therefore, by combining the branch current and the branch voltage of each branch, the abnormity detection of each branch in the energy storage inverter can be realized, namely the branch abnormity detection method of the energy storage system can realize the abnormity detection of each branch in the energy storage inverter; in addition, the branch anomaly detection method of the energy storage system can realize anomaly detection of each branch in the energy storage inverter only through software, so that additional hardware and matched hardware circuits do not need to be added in the energy storage inverter, and the branch anomaly detection cost of the energy storage inverter can be reduced.
Another embodiment of the present application provides a specific implementation manner of step S120, and a specific flow thereof is shown in fig. 2, and specifically includes the following steps:
s210, according to the branch current of each branch, determining a suspected abnormal branch in each branch.
The suspected abnormal branch is a branch suspected to be abnormal, and the suspected fault of the branch is specifically as follows: branch fuses in the branches are suspected to be abnormal; the reason why the branch circuit is suspected to be abnormal is that whether the branch circuit is abnormal or not can not be accurately judged only according to the branch circuit current.
And S220, after the suspected abnormal branches are determined, determining abnormal branches in the suspected abnormal branches according to the branch voltage of each branch.
In practical application, besides the above embodiment of step S120 provided in this embodiment, another embodiment is also included, specifically: determining suspected abnormal branches according to branch voltage, and then determining abnormal branches in each suspected abnormal branch according to branch current; the two embodiments are not specifically limited, and may be within the scope of the present application.
It should be noted that, in practical applications, when the branch fuse on the branch is abnormal, the branch current of the branch may change immediately, so that the current may be used as a basis to find the abnormality of the branch in time, and therefore, in practical applications, the former implementation of step S120 is a preferred implementation.
Another embodiment of the present application provides a specific implementation manner of step S210, and a specific flow thereof is shown in fig. 3, and specifically includes the following steps:
s211, judging whether the branch current of each branch is larger than or equal to the preset current.
If the branch current of at least one branch is smaller than the preset current, executing step S212; and if the branch current of each branch is greater than or equal to the preset current, stopping executing the branch abnormality detection method of the energy storage system.
S212, determining the branch circuit with the branch circuit current smaller than the preset current as a suspected abnormal branch circuit.
After the branch fuse on the branch is broken, the branch current on the branch is reduced, so that when the branch current of the branch is smaller than the preset current, it is considered that the branch fuse on the branch may be broken or the like.
Another embodiment of the present application provides a specific implementation manner of step S220, where the implementation manner is suitable for a single-stage mode energy storage system, and a specific flow of the implementation manner is shown in fig. 4, and specifically includes the following steps:
and S221, after the first preset time, judging whether absolute values of differences between the branch voltage of each suspected abnormal branch and the bus voltage of the direct-current bus in the energy storage inverter are all smaller than or equal to a first preset difference.
If the absolute value of the difference between the branch voltage and the bus voltage of at least one suspected abnormal branch is greater than the first preset difference, step S222 is executed.
In practical application, no matter the energy storage system is a single-stage mode energy storage system or a double-stage mode energy storage system, when a branch fuse on a branch is abnormal, the branch current of the branch can be changed immediately.
In the single-stage mode energy storage system, when a branch fuse on a branch is abnormal, the branch is still connected with a corresponding battery cluster, so that the branch voltage of the branch can be approximately consistent with the bus voltage in a short time; however, after the time is lengthened, the other branch circuits are charged or discharged under the action of the energy storage inverter, so that the bus voltage changes accordingly, that is, the branch circuit voltage of the branch circuit is no longer equal to the bus voltage, and thus whether the branch circuit is abnormal or not can be judged according to the change.
As can be seen from the above, the first preset time is used to ensure that the branch voltage of the abnormal branch is different from the branch voltage of the non-abnormal branch, so that the first preset time can be set according to experience.
In addition, because the branch voltage detected in practical application has an error, in order to avoid misjudgment, the judgment condition is improved to be that the difference value between the branch voltage and the bus voltage is greater than a first preset difference value from the condition that the branch voltage is not equal to the bus voltage.
Furthermore, it can be seen from the above that, in the first preset time, the energy storage inverter may charge the battery cluster and may also discharge the battery cluster, so that the branch voltage of the faulty branch may be smaller than the branch voltage of the non-faulty branch and may also be larger than the branch voltage of the non-faulty branch, and thus the difference between the branch voltage and the bus voltage is larger than the first preset difference, which is an improvement of the judgment condition that the absolute value of the difference between the branch voltage and the bus voltage is larger than the first preset difference.
S222, determining a suspected abnormal branch with the absolute value of the difference between the branch voltage and the bus voltage larger than a first preset difference as an abnormal branch.
In this embodiment, a further specific implementation manner of step S220 is provided, a specific flow of this implementation manner is shown in fig. 5, and this implementation manner further includes, after determining that the absolute values of the differences between the branch voltage and the bus voltage of each suspected abnormal branch are less than or equal to a first preset difference, the following steps:
and S223, judging whether the absolute values of the difference values between the branch voltage and the bus voltage of each suspected abnormal branch are less than or equal to the first preset difference value within second preset time.
If the absolute values of the difference values between the branch voltage and the bus voltage of each suspected abnormal branch are less than or equal to the first preset difference value within the second preset time, executing step S224; if the absolute values of the difference between the branch voltage and the bus voltage of each suspected abnormal branch are not less than or equal to the first preset difference within the second preset time, the step S221 is executed again.
And S224, judging that each branch suspected to be abnormal is not abnormal.
Another embodiment of the present application provides another specific implementation manner of step S220, which is applicable to a dual-stage mode energy storage system, and a specific flow of the implementation manner is shown in fig. 6, and specifically includes the following steps:
and S201, controlling the direct current converter corresponding to the suspected abnormal branch to stop or stand by.
In practical applications, the dc converter includes a DCDC conversion module and at least one dc switch connected in series.
The specific implementation mode for controlling the shutdown of the direct current converter is as follows: controlling the DCDC conversion module to stop power conversion, and closing at least one direct current switch; in practical applications, stopping the power conversion and closing the dc switch may be performed simultaneously, or may be performed first and then, and is not specifically limited herein, and is within the protection scope of the present application.
The specific implementation mode for controlling the standby of the direct current converter is as follows: controlling the DCDC conversion module to stop power conversion, and disconnecting at least one direct current switch; in practical applications, stopping the power conversion and turning off the dc switch may be performed simultaneously, or may be performed first and then, and is not specifically limited herein, and is within the protection scope of the present application.
S202, judging whether absolute values of differences between the branch voltage of each suspected abnormal branch and the bus voltage of the direct-current bus in the energy storage inverter are smaller than or equal to a second preset difference.
If the absolute value of the difference between the branch voltage and the bus voltage of at least one suspected abnormal branch is greater than the second preset difference, step S203 is executed.
It should be noted that the setting of the second preset difference and the setting of the absolute value in step S202 are the same as those in step S221, and are not described herein again.
S203, determining the suspected abnormal branch with the absolute value of the difference between the branch voltage and the bus voltage larger than a second preset difference as an abnormal branch.
In this embodiment, a further specific implementation manner of step S220 is provided, a specific flow of this implementation manner is shown in fig. 7, and this implementation manner further includes, after determining that the absolute values of the differences between the branch voltage and the bus voltage of each suspected abnormal branch are less than or equal to a second preset difference, the following steps:
s204, judging whether the absolute values of the difference values between the branch voltage and the bus voltage of each suspected abnormal branch are less than or equal to a second preset difference value within a second preset time.
If the absolute values of the difference values between the branch voltage and the bus voltage of each suspected abnormal branch are less than or equal to a second preset difference value within a second preset time, executing step S205; if the absolute values of the difference between the branch voltage and the bus voltage of each suspected abnormal branch are not less than or equal to the second preset difference within the second preset time, the step S202 is executed again.
It should be noted that the setting of the second preset difference and the setting of the absolute value in step S204 are the same as those in step S221, and are not described herein again.
And S205, judging that no abnormality occurs in each suspected abnormal branch.
The present embodiment further provides another specific implementation manner of step S220, a specific flow of this implementation manner is shown in fig. 8, and this implementation manner further includes, on the basis of the previous implementation manner, after step S205, the following steps:
and S206, controlling the starting operation of each direct current converter corresponding to each suspected abnormal branch.
The specific implementation mode for controlling the startup operation of the direct current converter comprises the following steps: controlling the DCDC conversion module to perform power conversion, and closing at least one direct current switch; in practical applications, the power conversion and the closing of the dc switch may be performed simultaneously, or may be performed first and then, and the specific limitations are not specifically limited herein, and the embodiments are within the scope of the present application.
Another embodiment of the present application provides another implementation manner of a branch anomaly detection method for an energy storage system, where in the energy storage system, the energy storage inverter further includes: and the DC side of the DCAC conversion module is respectively connected with each branch circuit through a DC bus.
On the basis of the foregoing embodiment, after determining that the operating power of the energy storage inverter is smaller than the preset power, as shown in fig. 9, the embodiment further includes the following steps:
s310, judging whether the DCAC conversion module is in standby state and/or whether each branch is respectively communicated with the corresponding battery cluster.
If the DCAC conversion module is in standby and/or each branch is respectively communicated with the corresponding battery cluster, executing step S320; and if the DCAC conversion module is not in standby and each branch is not communicated with the corresponding battery cluster, stopping executing the branch abnormality detection method of the energy storage system.
It should be noted that, before step S310, it is already determined that the operating power of the energy storage inverter is smaller than the preset power, and if it is determined that the DCAC conversion module is not in a standby state, it indicates that the DCAC conversion module is stopped; in addition, in general, each branch is simultaneously communicated with the corresponding battery cluster or is not simultaneously communicated with the corresponding battery, so as to fully utilize the energy storage system.
The embodiment provides a specific implementation manner for determining whether the DCAC conversion module is in standby mode, and the specific structure thereof is shown in fig. 10, which specifically includes the following steps:
s410, judging whether a main circuit in the DCAC conversion module stops power conversion or not, and whether a direct current side switch and an alternating current side switch in the DCAC conversion module are both closed or not.
If the main circuit in the DCAC conversion module stops power conversion and the dc-side switch and the ac-side switch in the DCAC conversion module are both closed, step S420 is executed; if the main circuit in the DCAC conversion module stops power conversion and the dc-side switch and the ac-side switch in the DCAC conversion module are both off, step S430 is performed.
And S420, judging that the DCAC conversion module is in standby.
And S430, judging that the DCAC conversion module is not in standby.
In addition, the judgment of whether each branch is respectively communicated with the corresponding battery cluster is only suitable for the energy storage system which is a single-stage mode energy storage system; the embodiment provides a specific implementation manner for determining whether both a dc-side switch and an ac-side switch in a DCAC conversion module are closed, and the specific structure of the embodiment is as shown in fig. 11, and specifically includes the following steps:
and S510, judging whether the switches in the switch boxes corresponding to the branches are closed or not.
If the switches in the switch boxes corresponding to the branches are closed, executing step S520; if none of the switches in the switch boxes corresponding to the branches are closed, step S530 is executed.
It should be noted that, in general, the switches in each switch box are all closed or opened simultaneously, so as to utilize the energy storage system to the maximum extent.
And S520, judging that each branch is respectively communicated with the corresponding battery cluster.
And S530, judging that each branch is not communicated with the corresponding battery cluster.
And S320, judging whether the absolute values of the difference values between the branch voltage of each branch and the bus voltage of the direct current bus in the energy storage inverter are all smaller than or equal to a third preset difference value.
If the absolute value of the difference between the branch voltage and the bus voltage of at least one branch is greater than the third preset value, step S330 is performed.
It should be noted that the setting of the third preset difference and the setting of the absolute value in step S320 are the same as those in step S221, and are not described herein again.
S330, determining the branch circuit with the absolute value of the difference value between the branch circuit voltage and the bus voltage larger than a third preset difference value as an abnormal branch circuit.
And S340, after the abnormal branch is determined, disconnecting the abnormal branch from the corresponding battery cluster.
The present embodiment further provides another embodiment of a branch anomaly detection method of an energy storage system, and a specific flow of this embodiment is as shown in fig. 12, and on the basis of the previous embodiment, after determining that absolute values of differences between branch voltages of each branch and a bus voltage of a dc bus in an energy storage inverter are all less than or equal to a third preset difference, the method further includes the following steps:
and S350, judging whether the absolute values of the difference values between the branch voltage and the bus voltage of each branch are less than or equal to a third preset difference value within a second preset time.
If the absolute values of the difference values between the branch voltage and the bus voltage of each branch are less than or equal to a third preset difference value within a second preset time, executing step S360; if the absolute values of the difference between the branch voltage and the bus voltage of each branch are not all less than or equal to the third preset difference within the second preset time, the process returns to step S320.
It should be noted that the setting of the third preset difference and the setting of the absolute value in step S350 are the same as those in step S221, and are not described herein again.
And S360, judging that each branch is not abnormal.
Another embodiment of the present application provides an energy storage system, whose specific structure is shown in fig. 13 (only two battery clusters 20 and two switch devices 30 are taken as examples), and specifically includes: a storage inverter 10, a controller (for simplicity of illustration, the controller is not shown in fig. 13), at least two battery clusters 20, and at least two switching devices 30; energy storage inverter 10, comprising: at least two branches 11; the connection relationship between the devices is specifically as follows:
one side of each branch 11 is connected with one-to-one corresponding battery cluster 20 through one-to-one corresponding switch device 30; the energy storage inverter 10 and each switching device 30 are controlled by a controller, and the controller is used for executing the branch circuit abnormality detection method of the energy storage system provided in the above embodiment.
In practical applications, as shown in fig. 13, the energy storage inverter 10 further includes: a direct current bus 12 and a DCAC conversion module 13; the other side of each branch 11 is connected with the direct current side of the DCAC conversion module 13 through a direct current bus 12; the alternating current side of the DCAC conversion module 13 is connected with the alternating current side of the energy storage inverter 10; the DCAC conversion module 13 is controlled by a controller.
The specific structure of the DCAC conversion module 13 is shown in fig. 14, and specifically includes: a main circuit 131, a dc-side switch 132, and an ac-side switch 133; the dc side of the main circuit 131 is connected to the dc side of the DCAC conversion module 13 through a dc side switch 132; the ac side of the main circuit 131 is connected to the ac side of the DCAC conversion module 13 through an ac side switch 133; the dc-side switch 132 and the ac-side switch 133 are controlled by a controller.
Alternatively, the switching device 30 may be a switch box 31, as shown in fig. 15, in which case the energy storage system is a single-stage mode energy storage system, wherein the switch box 31 includes a fuse FU and a switch S connected in series with each other; the switching device 30 may also be a dc converter 32, as shown in fig. 16, where the energy storage system is a two-stage mode energy storage system, where the dc converter 32 includes a DCDC conversion module 321 and at least one dc switch Sd connected in series; it is not specifically limited herein, and may be within the scope of the present application depending on the specific circumstances.
In the above description of the disclosed embodiments, features described in various embodiments in this specification can be substituted for or combined with each other to enable those skilled in the art to make or use the present application. The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present teachings, or modify equivalent embodiments to equivalent variations, without departing from the scope of the present teachings, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are within the scope of the technical solution of the present invention, unless the technical essence of the present invention is not departed from the content of the technical solution of the present invention.
Claims (20)
1. The branch abnormality detection method of the energy storage system is characterized in that an energy storage inverter in the energy storage system comprises at least two branches, and the branches are indirectly connected with battery clusters in the energy storage system in a one-to-one correspondence manner; the branch anomaly detection method of the energy storage system comprises the following steps:
judging whether the running power of the energy storage inverter is greater than or equal to a preset power;
if the operating power of the energy storage inverter is greater than or equal to the preset power, determining an abnormal branch in each branch by combining the branch current and the branch voltage of each branch; the abnormal branch is the branch with the abnormality;
and after the abnormal branches are determined, disconnecting each abnormal branch from the corresponding battery cluster.
2. The branch circuit abnormality detection method of the energy storage system according to claim 1, wherein determining an abnormal branch circuit in each of the branch circuits in combination with the branch circuit current and the branch circuit voltage of each of the branch circuits comprises:
according to the branch current of each branch, determining a suspected abnormal branch in each branch; the suspected abnormal branch is the branch suspected to be abnormal;
and after the suspected abnormal branches are determined, determining the abnormal branches in each suspected abnormal branch according to the branch voltage of each branch.
3. The branch circuit abnormality detection method of the energy storage system according to claim 2, wherein determining a suspected abnormal branch circuit in each branch circuit according to the branch circuit current of each branch circuit comprises:
judging whether the branch current of each branch is greater than or equal to a preset current or not;
if the branch current of at least one branch is smaller than the preset current, determining the branch with the branch current smaller than the preset current as the suspected abnormal branch.
4. The method according to claim 2, wherein if the branches are connected to the corresponding battery clusters through one-to-one switch boxes in the energy storage system, determining the abnormal branch in each of the suspected abnormal branches according to the branch voltage of each branch comprises:
after a first preset time, judging whether absolute values of differences between branch voltages of the suspected abnormal branches and bus voltages of a direct current bus in the energy storage inverter are all smaller than or equal to a first preset difference;
if the absolute value of the difference between the branch voltage of at least one suspected abnormal branch and the bus voltage is larger than the first preset difference, determining the suspected abnormal branch of which the absolute value of the difference between the branch voltage and the bus voltage is larger than the first preset difference as the abnormal branch.
5. The method according to claim 2, wherein if the branches are connected to the corresponding battery clusters through one-to-one dc converters in the energy storage system, determining the abnormal branch in each of the suspected abnormal branches according to the branch voltage of each of the branches includes:
controlling the direct current converter corresponding to the suspected abnormal branch to stop or stand by;
judging whether the absolute values of the difference values between the branch voltage of each suspected abnormal branch and the bus voltage of the direct-current bus in the energy storage inverter are smaller than or equal to a second preset difference value;
if the absolute value of the difference between the branch voltage of at least one suspected abnormal branch and the bus voltage is larger than the second preset difference, determining the suspected abnormal branch with the absolute value of the difference between the branch voltage and the bus voltage larger than the second preset difference as the abnormal branch.
6. The branch circuit abnormality detection method of the energy storage system according to claim 5, wherein controlling the dc converter to be in standby comprises:
controlling a DCDC conversion module in the DC converter to stop power conversion, and closing at least one DC switch in the DC converter;
controlling the DC converter to shut down, comprising:
and controlling the DCDC conversion module to stop power conversion, and opening at least one direct current switch.
7. The branch abnormality detection method of the energy storage system according to claim 1, wherein the energy storage inverter further includes: the DC side is respectively connected with the DCAC conversion module of each branch circuit through a DC bus; after the operating power of the energy storage inverter is judged to be smaller than the preset power, the method further comprises the following steps:
judging whether the DCAC conversion module is in standby state and/or whether each branch is respectively communicated with the corresponding battery cluster;
if the DCAC conversion module is in standby and/or each branch is respectively communicated with the corresponding battery cluster, judging whether the absolute values of the difference values between the branch voltage of each branch and the bus voltage of the direct-current bus in the energy storage inverter are smaller than or equal to a third preset difference value;
if the absolute value of the difference value between the branch voltage of at least one branch and the bus voltage is greater than the third preset difference value, determining the branch with the absolute value of the difference value between the branch voltage and the bus voltage greater than the third preset difference value as an abnormal branch;
and after the abnormal branch is determined, disconnecting the abnormal branch from the corresponding battery cluster.
8. The method for detecting the branch circuit abnormality of the energy storage system according to claim 7, wherein the step of judging whether the DCAC conversion module is in a standby state comprises the steps of:
judging whether a main circuit in the DCAC conversion module stops power conversion or not, and whether a direct current side switch and an alternating current side switch in the DCAC conversion module are both closed or not;
and if the main circuit stops power conversion and the direct current side switch and the alternating current side switch are both closed, judging that the DCAC conversion module is in a standby state.
9. The method for detecting branch circuit abnormality of an energy storage system according to claim 7, wherein the judgment as to whether each of the branch circuits is respectively communicated with the corresponding battery cluster is only applicable to the energy storage system in which the branch circuits are connected with the corresponding battery cluster through one-to-one corresponding switch boxes;
judging whether each branch is respectively communicated with the corresponding battery cluster or not, comprising the following steps:
judging whether the switches in the switch boxes corresponding to the branches are closed or not;
and if the switches in the switch boxes corresponding to the branches are closed, determining that the branches are respectively communicated with the corresponding battery clusters.
10. The method for detecting branch circuit abnormality of the energy storage system according to any one of claims 1 to 9, wherein if the branch circuit is connected to the corresponding battery cluster through one-to-one corresponding switch box in the energy storage system, disconnecting the abnormal branch circuit from the corresponding battery cluster includes:
and controlling the switch in the switch box corresponding to the abnormal branch to be switched off.
11. The method for detecting branch circuit abnormality of an energy storage system according to any one of claims 1 to 9, wherein if the branch circuit is connected to the corresponding battery cluster through one-to-one corresponding dc converters in the energy storage system, disconnecting the abnormal branch circuit from the corresponding battery cluster includes:
and controlling the direct current converter corresponding to the abnormal branch circuit to stop.
12. The method for detecting branch circuit abnormality of an energy storage system according to any one of claims 1 to 9, after determining that the absolute values of the differences between the branch circuit voltage of each target branch circuit and the bus voltage of the dc bus in the energy storage inverter are all less than or equal to the corresponding preset difference, further comprising:
judging whether the absolute values of the difference values between the branch voltage of each target branch and the bus voltage are less than or equal to corresponding preset difference values within second preset time; the target branch is a suspected abnormal branch or the branch;
if the absolute value of the difference between the branch voltage of each target branch and the bus voltage is less than or equal to the corresponding preset difference within the second preset time, determining that each target branch is not abnormal;
and if the absolute values of the difference values between the branch voltage of each target branch and the bus voltage are not less than or equal to the corresponding preset difference value within the second preset time, returning to execute the step of judging whether the absolute values of the difference values between the branch voltage of each target branch and the bus voltage of the direct-current bus in the energy storage inverter are less than or equal to the corresponding preset difference value.
13. The method according to claim 12, wherein if the branches are connected to the corresponding battery clusters through dc converters corresponding to one another in the energy storage system, after determining that no abnormality has occurred in each of the target branches from the voltage difference, the method further comprises:
and controlling the starting operation of each direct current converter corresponding to each target branch.
14. The method according to claim 13, wherein controlling the dc converter to start up comprises:
and the DCDC conversion module in the DC converter performs power conversion and controls the closing of a DC switch in the DC converter.
15. An energy storage system, comprising: the system comprises an energy storage inverter, a controller, at least two battery clusters and at least two switching devices; the energy storage inverter includes: at least two branches; wherein:
one side of each branch circuit is connected with the battery clusters in one-to-one correspondence through the switch devices in one-to-one correspondence;
the energy storage inverter and each switching device are controlled by the controller, and the controller is used for executing the branch circuit abnormality detection method of the energy storage system according to any one of claims 1 to 14.
16. The energy storage system of claim 15, wherein each of the switching devices is a switch box or a dc converter.
17. The energy storage system of claim 16, wherein the switch box comprises: a fuse and a switch connected in series with each other.
18. The energy storage system of claim 16, wherein the dc converter comprises: DCDC conversion module and at least one direct current switch that mutual series connection.
19. The energy storage system of any of claims 15 to 18, wherein the energy storage inverter further comprises: a DC bus and a DCAC conversion module; wherein:
the other side of each branch circuit is connected with the direct current side of the DCAC conversion module through the direct current bus;
the alternating current side of the DCAC conversion module is connected with the alternating current side of the energy storage inverter;
the DCAC conversion module is controlled by the controller.
20. The energy storage system of claim 19, wherein the DCAC conversion module comprises: the main circuit, the direct current side switch and the alternating current side switch; wherein:
the direct current side of the main circuit is connected with the direct current side of the DCAC conversion module through the direct current side switch;
the alternating current side of the main circuit is connected with the alternating current side of the DCAC conversion module through the alternating current side switch;
the direct current side switch and the alternating current side switch are controlled by the controller.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115891660A (en) * | 2023-03-10 | 2023-04-04 | 宁德时代新能源科技股份有限公司 | Battery replacement connector detection method, device, circuit, electronic equipment and storage medium |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115891660A (en) * | 2023-03-10 | 2023-04-04 | 宁德时代新能源科技股份有限公司 | Battery replacement connector detection method, device, circuit, electronic equipment and storage medium |
| CN115891660B (en) * | 2023-03-10 | 2023-12-26 | 宁德时代新能源科技股份有限公司 | Method, device, circuit, electronic equipment and storage medium for detecting replacement connector |
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