CN113270893A - Photovoltaic turn-off system control method and application system thereof - Google Patents
Photovoltaic turn-off system control method and application system thereof Download PDFInfo
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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
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/06—Details with automatic reconnection
- H02H3/063—Details concerning the co-operation of many similar arrangements, e.g. in a network
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/06—Details with automatic reconnection
- H02H3/066—Reconnection being a consequence of eliminating the fault which caused disconnection
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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
- 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
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- 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
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Abstract
The invention provides a control method of a photovoltaic turn-off system and an application system thereof, which are applied to the technical field of photovoltaic power generation, the method is applied to the photovoltaic turn-off system comprising an inverter system and at least two turn-off systems, after at least two target turn-off systems are determined in each turn-off system, the turn-on of each target turn-off system is sequentially controlled according to the preset start interval duration, because the preset start interval duration is less than the duration of the on state of the turn-off system maintained under the condition that the direct current bus voltage and/or current fluctuation is not detected, at least one turn-off system is in the on state at the same time in the start duration of the inverter system, the working voltage required by start-up self-check can be provided for the inverter system, even if the input voltage of the inverter system in the start duration is in the preset range, the inverter system can be controlled to finish the start-up, the problem of among the prior art inverter system be in the state of starting the self-checking for a long time, unable normal output power is solved.
Description
Technical Field
The invention relates to the technical field of photovoltaic power generation, in particular to a photovoltaic turn-off system control method and an application system thereof.
Background
Referring to fig. 1, fig. 1 is a block diagram of a photovoltaic shutdown system in the prior art, each photovoltaic module in the system and a corresponding cascade-connected shutdown device form a shutdown system, the shutdown system is connected to an inverter system, when a safety fault occurs in the photovoltaic shutdown system, the output voltage of the corresponding photovoltaic module can be rapidly reduced through the shutdown system, so that the voltage of the whole system is reduced, the whole system is rapidly shut down, and when the safety fault disappears, each shutdown device in the shutdown system can be turned on again to recover the electric energy output of the photovoltaic module connected to itself.
In the prior art, after a shutdown system is turned on, a continuous on-time corresponds to a duration for which each shutdown device in the shutdown system maintains an on-state under the condition that voltage and/or current fluctuation of a direct current bus cannot be detected. Furthermore, the inverter system needs to perform necessary starting detection such as ground insulation resistance detection and relay failure detection in the starting process, and the time required by the starting detection is the starting time of the inverter system.
Based on the above, the prior art has the following problems in application: when the inverter system is in a starting self-checking state, the direct current bus in the photovoltaic turn-off system is in an open circuit state, and the change of voltage and/or current cannot be generated, so that the turn-off system is turned off after the turn-on time reaches the corresponding continuous turn-on time, the voltage of the direct current bus is reduced to almost zero, and the inverter system fails to be started because the starting time of the inverter system is longer than the continuous turn-on time of the turn-off device. In the starting process of the next period, the inverter system needs to be started again for detection, the inverter system fails to be started again due to the shutdown of the shutdown system, and the startup of the shutdown system and the inverter system self-checking continue to circulate in cycles, so that the inverter system is in the self-checking starting state for a long time and cannot normally output power.
Disclosure of Invention
The invention provides a photovoltaic turn-off system control method and an application system thereof, which are used for sequentially controlling the turn-on of each turn-off system in a photovoltaic turn-off system according to a preset turn-on interval duration, so that at least one turn-off system is in the on state at the same moment in the turn-on duration, thereby ensuring that the input voltage of an inverter system is in a preset voltage range and ensuring that the inverter system is successfully started.
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 photovoltaic turn-off system control method, applied to a photovoltaic turn-off system including an inverter system and at least two turn-off systems, the method including:
determining at least two target turn-off systems in each turn-off system;
sequentially controlling the turning-on of each target turn-off system according to a preset starting interval duration so that the input voltage of the inverter system in the starting duration is in a preset range;
the preset starting interval duration is less than the duration of the on state of the turn-off system when the direct current bus voltage and/or current fluctuation is not detected;
and controlling the inverter system to start or be in a zero-power grid-connected mode.
Optionally, the sequentially controlling the turn-on of each target turn-off system according to a preset start interval duration includes:
controlling the ith target turn-off system to be turned on and starting timing;
if the timing time reaches the preset starting interval time, controlling the (i + 1) th target turn-off system to be turned on until all the target turn-off systems are traversed;
wherein i ∈ [1, N-1], N is the total number of the target shutdown systems.
Optionally, the process of controlling the turning on of any one of the target turn-off systems includes:
and controlling the target turn-off system to be turned on according to a preset turn-on period.
Optionally, the process of controlling the target turn-off system to be turned on in any one preset turn-on period includes:
and controlling the voltage change of the direct current bus connected with the target turn-off system until the target turn-off system is turned on when the change characteristic of the voltage of the connected direct current bus meets a preset turn-on condition according to the output voltage of the target turn-off system.
Optionally, the controlling the voltage change of the dc bus connected to the target shutdown system includes:
and controlling the voltage of a direct current bus connected with the target turn-off system to change in a pulse waveform manner.
Optionally, the preset starting interval duration is determined based on the number of the target turn-off systems and the preset turn-on period.
Optionally, a quotient of the preset turn-on period and the number of the target turn-off systems is used as the preset start interval duration.
Optionally, the inverter system includes a plurality of voltage control circuits for connecting the shutdown system;
the determining of at least two target shutdown systems in each of the shutdown systems includes:
determining available voltage control circuits in each of the voltage control circuits;
determining at least two target voltage control circuits in each of the available voltage control circuits;
and taking the shutdown system corresponding to each target voltage control circuit as a target shutdown system.
Optionally, the determining available voltage control circuit in each voltage control circuit includes:
respectively detecting the bus voltage of the direct current bus corresponding to each voltage control circuit;
judging the number of the turn-off devices connected with the corresponding voltage control circuit according to the bus voltage;
and using the voltage control circuits with the number of the connected turn-off devices larger than a preset threshold value as the available voltage control circuits.
Optionally, after the inverter system is successfully started, the photovoltaic strings corresponding to the shutdown systems are controlled to output power corresponding to the maximum power point.
In a second aspect, the present invention provides an inverter system, comprising: an inverter circuit, an inverter controller, and at least two voltage control circuits,
the output end of each voltage control circuit is connected with the direct current side of the inverter circuit;
the input end of each voltage control circuit is connected with at least one turn-off system;
the inverter controller is respectively connected with the inverter circuit and the control end of each voltage control circuit;
the inverter controller executes the photovoltaic shutdown system control method according to any one of the first aspect of the present invention.
Optionally, the voltage control circuit includes a BOOST circuit.
In a third aspect, the present invention provides a photovoltaic turn-off system comprising at least two turn-off systems and the inverter system of any one of the second aspects of the present invention, wherein,
and each turn-off system is respectively connected with the inverter system.
Optionally, the shutdown system includes: a plurality of photovoltaic modules, a plurality of turn-off devices and a direct current bus, wherein,
the output ends of the shut-off devices are cascaded, and the cascaded connection ports of the shut-off devices are connected with the inverter system through the direct current bus;
and the input end of each shutoff device is respectively connected with the output end of at least one corresponding photovoltaic module.
The invention provides a control method of a photovoltaic turn-off system, which is applied to the photovoltaic turn-off system comprising an inverter system and at least two turn-off systems, wherein after at least two target turn-off systems are determined in each turn-off system, the turn-on of each target turn-off system is sequentially controlled according to the preset start interval duration, because the preset start interval duration is less than the duration of the turn-on state of the turn-off system under the condition that the direct current bus voltage and/or current fluctuation is not detected, at least one turn-off system is in the on state at the same time in the start duration of the inverter system, the working voltage required by the start self-check can be provided for the inverter system, even if the input voltage of the inverter system in the start duration is in the preset range, the inverter system can be controlled to finish the start, and the problem that the inverter system in the prior art is in the state of the start self-check for a long time is solved, the power can not be output normally.
Furthermore, the method provided by the invention can also support the inverter system to be in a zero-power grid-connected mode, so that the inverter system in a zero-power output state cannot be stopped due to misjudgment of faults.
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 block diagram of a photovoltaic shutdown system in the prior art;
fig. 2 is a block diagram of a photovoltaic shutdown system to which the present invention is applied;
fig. 3 is a flowchart of a control method of a photovoltaic shutdown system according to an embodiment of the present invention;
fig. 4 is a block diagram of another photovoltaic shutdown system to which the present invention is applied;
fig. 5 is a flowchart of a method for determining a target shutdown system in a control method provided in an embodiment of the present invention;
fig. 6 is a flowchart of a method for controlling the start of each target shutdown system in the control method provided in the embodiment of the present invention;
fig. 7 is a waveform schematic diagram of a starting process of a photovoltaic shutdown system according to an embodiment of the present invention;
fig. 8 is a waveform schematic diagram of another photovoltaic shutdown system startup process provided by the embodiment of the invention;
fig. 9 is a block diagram of a structure of still another photovoltaic shutdown system to which the present invention is applied;
fig. 10 is a waveform schematic diagram of a startup process of a photovoltaic shutdown system according to another embodiment of the present invention;
fig. 11 is a waveform diagram of the photovoltaic turn-off system in the zero-power grid-connection mode.
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.
First, it should be noted that the photovoltaic shutdown system control method provided by each embodiment of the present invention is applied to a photovoltaic shutdown system including an inverter system and at least two shutdown systems. Optionally, referring to fig. 2, the embodiment shown in fig. 2 is exemplified by including two shutdown systems, and a basic structure of the photovoltaic shutdown system is described. In the photovoltaic turn-off system, each turn-off system is respectively connected with a direct current input end of an inverter system, and the inverter system converts the obtained direct current to obtain alternating current and outputs the alternating current to an alternating current power grid or an electric load. As shown in fig. 2, the inverter system includes multiple voltage control circuits and inverter circuits, an input end of one voltage control circuit is connected to at least one turn-off system (one of which is shown in fig. 2), and output ends of the voltage control circuits are connected in parallel to a dc side of the inverter circuit. The voltage control circuit mainly controls the direct-current voltage accessed to the inverter circuit, meanwhile, the voltage control circuit can also control the voltage of a direct-current bus connecting the voltage control circuit with the corresponding turn-off system, and further realizes the control of the working state of the turn-off system through the voltage control of the direct-current bus of the turn-off system.
The specific design of the individual shut-off systems can be implemented in conjunction with the prior art and is not expanded here.
Based on the above, the present invention provides a method for controlling a photovoltaic shutdown system, which is applied to the photovoltaic shutdown system shown in fig. 2, and in particular, may be applied to an inverter controller of an inverter circuit in an inverter system, and may also be applied to other controllers that may control a shutdown system and a working process of the inverter system in the photovoltaic shutdown system, and certainly, in some cases, may also be applied to a server on a network side. Optionally, referring to fig. 3, a flow of the control method provided in the embodiment of the present invention may include:
s100, determining at least two target turn-off systems in each turn-off system.
In practical applications, the inverter system includes more than two voltage control circuits, and any one of the voltage control circuits is connected to at least one shutdown system, so it should be emphasized that, in the at least two target shutdown systems mentioned in this embodiment, each target shutdown system is an independent shutdown system connected to different connection interfaces of the inverter system, specifically, the voltage control circuits connected to the target shutdown systems are different from each other. That is, if one voltage control circuit is connected with two or more shutdown systems, when the control method is applied, all the shutdown systems connected to the voltage control circuit are simultaneously started or closed, so that only all the shutdown systems connected to the voltage control circuit can be used as a target shutdown system.
Further, referring to fig. 4, fig. 4 shows another situation in the practical application of the photovoltaic turn-off system, in this scenario, the inverter system includes multiple voltage control circuits, and in each voltage control circuit, at least one voltage control circuit is not actually connected with the turn-off system, in this case, the voltage control circuit not connected with the turn-off system obviously cannot participate in the control process.
Therefore, based on the above, at least two target shutdown systems need to be selected from a plurality of shutdown systems, specifically, referring to fig. 5, fig. 5 shows a method for determining a target shutdown system, and the process may include:
s1001 specifies a usable voltage control circuit among the voltage control circuits.
In the present embodiment, the available voltage control circuit refers to a voltage control circuit to which a shutdown system is connected. Since the output of the shutdown system directly affects the bus voltage of the dc bus between the shutdown system and the voltage control circuit, it can be determined whether the voltage control circuit is the available control circuit described in this embodiment based on the dc bus voltage corresponding to each voltage control circuit.
Specifically, the voltages of the dc buses corresponding to the voltage control circuits are respectively detected, and the number of the shutdown devices for sending the start voltage to the corresponding dc bus is determined according to the obtained dc bus voltage, that is, the number of the shutdown devices connected to the voltage control circuits is determined, and if the number of the shutdown devices connected to any one of the voltage control circuits is greater than a preset threshold, it may be determined that the voltage control circuit may be used as an available voltage control circuit.
And S1002, determining at least two target voltage control circuits in each available voltage control circuit.
After the available voltage control circuits are determined, at least two available voltage control circuits can be arbitrarily selected as the target voltage control circuit according to requirements in each available voltage control circuit. As for the specific selection number of the target voltage control circuits, only two or more may be selected, and of course, all the available voltage control circuits may be used as the target voltage control circuits.
And S1003, taking the shutdown system corresponding to each target voltage control circuit as a target shutdown system.
After the target voltage control circuit is determined, a shutdown system connected to the target voltage control circuit, that is, the target shutdown system described in this embodiment.
As described above, if there are a plurality of shutdown systems corresponding to any one target voltage control circuit, the plurality of shutdown systems connected to the target voltage control circuit are simultaneously used as target shutdown systems, but the target shutdown systems connected to the same target voltage control circuit are simultaneously turned on and simultaneously turned off.
And S110, sequentially controlling the turning-on of each target turn-off system according to a preset starting interval duration so that the input voltage of the inverter system in the starting duration is in a preset range.
As described above, after any shutdown system is turned on, the on state is maintained for a certain period of time without detecting the voltage and/or current fluctuation of the dc bus connected to the shutdown system, and it is important that each photovoltaic module in the shutdown system is in a normal output state within the on-state maintaining duration, so that the bus voltage of the dc bus can be maintained within the preset range required by the normal start and self-test of the inverter circuit.
Based on this, in order to ensure that the input voltage of the inverter system is always within the preset range within the starting time, the control method sequentially controls each target turn-off system to be turned on according to the preset starting interval, because the preset starting interval time is less than the duration of the on-state of the turn-off system when the direct current bus voltage and/or current fluctuation is not detected, and each target turn-off system is connected with the input end of the inverter system in parallel, at least one target turn-off system is in the on-state at any moment in the starting process of the inverter system before all the target turn-off systems are traversed, the input voltage within the preset range is provided for the inverter system, and the inverter system can be normally started.
Optionally, referring to fig. 6, fig. 6 shows an optional implementation flow of this step, where the flow includes:
and S1101, controlling the ith target shutdown system to be switched on, and starting timing.
Wherein i belongs to [1, N-1], wherein N is the total number of the target shutdown systems.
It is conceivable that, when first executed, i is 1, i.e., the 1 st target shutdown system is controlled to be turned on. And when the system is controlled to be switched on sequentially, the control method is the same.
Optionally, in practical application, after the inverter system is started, power output is often required to be performed immediately, and in order to accelerate a process of accessing each shutdown system in the entire photovoltaic shutdown system to the system, turning on of each target shutdown system may be controlled according to a preset turning-on period, that is, turning on of each target shutdown system is repeatedly controlled, where the preset turning-on period includes a time length for controlling the turn-on of the shutdown system and a duration time length for maintaining a turning-on state without detecting fluctuation of voltage and/or current of a dc bus connected to the preset turning-on period after the shutdown system is turned on. It is conceivable that, when any one of the target shutdown systems is in the off state, at least one of the other target shutdown systems is in the on state, and the input voltage of the inverter system is stable.
Specifically, in any preset turn-on period, the voltage change of the dc bus connected to the target turn-off system is controlled, for example, the voltage of the dc bus corresponding to the target turn-off system may be controlled to change in a pulse waveform, so that the target turn-off system is turned on when the change characteristic of the voltage of the dc bus connected to the target turn-off system is determined to meet the preset turn-on condition according to the output voltage of the target turn-off system. The specific implementation method for judging whether the turn-on is performed by the turn-off system according to the output voltage of the turn-off system can be implemented based on the prior art, and the invention is not limited to this.
And after the ith target turn-off system is turned on, synchronously starting timing, and counting the time length of the ith target turn-off system in the on state.
And S1102, judging whether the timing duration reaches a preset starting interval duration, and if so, executing S1103.
If the timing duration of the ith target turn-off system in the on state reaches the preset starting interval duration, executing S1103, and if the timing duration does not reach the preset starting interval duration, continuing to wait until the timing duration reaches the preset starting interval duration.
And S1103, judging whether all the target shutdown systems are traversed or not, and if not, executing S1104.
After the timing duration of the ith target turn-off system in the on state reaches the preset start interval duration, if all the target turn-off systems are not traversed, the step S1104 is continuously executed, and on the contrary, if all the target turn-off systems are traversed, that is, the ith target turn-off system is the last target turn-off system, the execution of the current step may be exited.
S1104, let i equal i +1, and return to execution S1101.
And under the condition that all target shutdown systems are not traversed, adding 1 to the value of i to determine the next target shutdown system, and returning to the step S1101. It should be noted that, i ═ i +1 mentioned in this step is only to illustrate that the next target shutdown system needs to be controlled to be turned on, and is not to be taken as a limitation to a specific implementation manner. Of course, the ordering of the target turn-off devices may be flexibly set according to the needs, which is not limited in the present invention.
Optionally, under the condition that each target turn-off system is repeatedly turned on according to a preset on-period, the preset start interval duration may be determined based on the number of target turn-off devices and the preset on-period corresponding to the turn-off system. Specifically, a quotient of the preset turn-on period and the number of the target turn-off systems may be calculated, and the obtained quotient is used as the preset start interval duration. Of course, the preset start interval duration may also be determined in other manners, as long as the preset start interval duration is less than the duration that the target turn-off system maintains the on state. It is conceivable that if the duration of the preset start-up interval is less than the quotient of the preset on-period and the number of target off-systems, this means that at least two target off-systems in the system are in an on-state at some point in time.
And S120, controlling the inverter system to start or be in a zero-power grid-connected mode.
It should be emphasized that, in practical application, there are various options for executing the step, and the inverter system can be immediately controlled to start or enter a zero-power grid-connected mode after the first target turn-off system is controlled to be turned on; correspondingly, if the number of the target turn-off systems is large, or the duration of the on state of any one target turn-off system is long under the condition that the direct current bus voltage and/or current fluctuation is not detected, so that the total duration of the input voltage of the inverter system in the preset range is longer than the duration required by the inverter system to finish starting, in this case, the inverter system can be started after delaying for a certain time after controlling the first target turn-off system to be started. In this embodiment, S120 is described after S110 for convenience of explaining the control method provided by the present invention, but the order of execution of the two is not strictly limited.
As for the specific processes of controlling the starting of the inverter system and the zero-power grid-connected mode, the control method can be realized by referring to the prior art, and is not expanded here.
Optionally, after the inverter system is controlled to be started, the target shutdown system and the photovoltaic modules corresponding to other shutdown systems except the target shutdown system can be further controlled to output power corresponding to the maximum power point, so that the established function of the photovoltaic shutdown system is realized.
In summary, the control method provided in the embodiments of the present invention sequentially controls the turn-on of each target turn-off system according to the preset start interval duration, and since the preset start interval duration is less than the duration of the turn-on state of the turn-off system when the dc bus voltage and/or current fluctuation is not detected, it can be ensured that at least one turn-off system is in the turn-on state at the same time within the start duration of the inverter system, and the operating voltage required for the startup self-test can be provided to the inverter system, even if the input voltage of the inverter system within the start duration is within the preset range, so that the inverter system can be controlled to complete the start-up, and the problem that the inverter system in the prior art is in the state of startup self-test for a long time and cannot normally output power is solved.
Furthermore, the method provided by the invention can also support the inverter system to be in a zero-power grid-connected mode, so that the inverter system in a zero-power output state cannot be stopped due to misjudgment of faults.
It should be noted that, as a most typical implementation scenario, the photovoltaic system turns off two target turn-off systems, and the second target turn-off system is immediately started after the first target turn-off system reaches a preset start interval duration, in this case, the accumulated duration of the input voltage of the inverter system within the preset range is the sum of the continuous on-times of the two target turn-off systems, and in practical application, based on the setting of the inverter system in the prior art, the start duration of the inverter system is necessarily smaller than the sum of the continuous on-times of the two target turn-off systems, and the control method provided by the present invention is necessarily feasible. Of course, the above conditions are easier to satisfy and are equally feasible in the case of multiple target shutdown systems.
The control method provided by the invention is described below with reference to a specific photovoltaic turn-off system.
In the embodiment shown in fig. 2, the photovoltaic turn-off system includes two turn-off systems, both of which serve as target turn-off systems, and further, the inverter system includes two voltage control circuits and an inverter circuit. Specifically, in this embodiment, the voltage control circuit is a BOOST circuit. For convenience of description, in the following embodiments, the process of controlling the activation of the shutdown system is referred to as activation beating.
Based on the above, fig. 7 shows the starting process of the photovoltaic shutdown system when the BOOST circuit is in the through state. Firstly, a first target turn-off system is started through starting a wave beating operation, and high-voltage direct current is generated on a first direct current bus corresponding to the first target turn-off system. For example, when the first dc bus includes 20 photovoltaic modules, the high-voltage dc voltage on the first dc bus may reach 800V. At time t0, the voltage on the first dc bus is established, the dc bus voltage of the inverter circuit is also established, and the inverter circuit starts to perform a start-up self-test. And after the wave striking starting operation of the first direct current bus, waiting for a preset starting interval time delta t, and carrying out wave striking starting on the second direct current bus. Before time t1, the voltage on the second dc bus is established. At the time t1, the voltage of the first direct current bus decreases, and due to the existence of the voltage of the second direct current bus, the voltage of the direct current bus of the inverter circuit is still within the preset range, and the starting self-checking operation of the inverter circuit is not affected. At time t2, the first target shutdown system again initiates a start-up ripple, producing high voltage dc on the first dc bus. At time t3, the inverter circuit completes the startup self-test, which takes t3-t 0. After time t3, the inverter circuit in the inverter circuit starts operating. And in the maximum power tracking process, the voltage of the second direct current bus is reduced to the maximum power point voltage from the open circuit voltage, and the current of the second direct current bus is increased from zero. After the high-voltage direct-current voltage of the first direct-current bus is established, the first direct-current bus can rapidly output power because the inverter circuit finishes the starting self-test. After the first direct current bus and the second direct current bus output power, the corresponding turn-off device can maintain the turn-on of the corresponding turn-off device by detecting the input or output voltage and current characteristics of the corresponding turn-off device, and the photovoltaic turn-off system is started successfully.
Further, fig. 8 shows a starting process of the photovoltaic shutdown system when the BOOST circuit is in the BOOST state. Firstly, a first target turn-off system is started through starting and wave beating, and high-voltage direct current is generated on a first direct current bus corresponding to the first target turn-off system. For example, when 10 photovoltaic modules are included on the first dc bus, the high voltage dc voltage on the first dc bus may reach 400V. At time t0, the voltage on the first dc bus is established, the dc bus voltage of the inverter circuit is established, and the inverter circuit starts to perform a start-up self-test. After the wave striking starting operation of the first direct current bus, waiting for a preset starting interval time delta t, and carrying out the wave striking starting operation on the second direct current bus. Before time t1, a DC high voltage on the second DC bus builds. At the time t1, the voltage of the first direct current bus decreases, and due to the existence of the voltage of the second direct current bus, the voltage of the direct current bus of the inverter circuit is still within the preset range, and the starting self-checking operation of the inverter circuit is not affected. At time t2, the inverter circuit again activates each shut-off device in the first dc bus by initiating a ripple operation, producing high voltage dc on the first dc bus. At time t3, the inverter circuit completes the startup self-test, which takes t3-t 0. After time t3, the inverter circuit in the inverter circuit starts operating. The second direct-current voltage is lower than the direct-current bus voltage required by the normal work of the inverter circuit, the Boost circuit is in a Boost state, the Boost circuit carries out maximum power point tracking on the second direct-current bus, in the maximum power point tracking process, the voltage of the second direct-current bus is reduced to the maximum power point voltage from the open-circuit voltage, and the current of the second direct-current bus is increased from zero. After the high-voltage direct-current voltage of the first direct-current bus is established, the first direct-current bus can rapidly output power because the inverter circuit finishes the starting self-test. After the first direct current bus and the second direct current bus output power, the corresponding turn-off device can maintain the turn-on of the corresponding turn-off device by detecting the input or output voltage and current characteristics of the corresponding turn-off device, and the photovoltaic turn-off system is started successfully.
Based on the above, it can be seen that the difference between the embodiments shown in fig. 7 and fig. 8 is that the operation of maximum power point tracking after the self-inspection of the inverter circuit is completed is different, and the staggered start-up wave beating method is consistent.
Further, the embodiment shown in fig. 9 illustrates an application scenario in which the photovoltaic turn-off system includes three turn-off systems, and each of the three turn-off systems is used as a target turn-off system.
In connection with the configuration of the photovoltaic shutdown system shown in fig. 9, the startup process of the system may be as shown in fig. 10. Specifically, after the operation of wave-striking starting is performed on the first target turn-off system, the voltage of the first direct-current bus corresponding to the first target turn-off system is established, and after the preset starting interval duration Δ t1 is waited, the operation of wave-striking starting is performed on the second target turn-off system. After the operation of the second target shutdown system for the start of the wave starting, the preset starting interval duration delta t2 is waited, and the operation of the wave starting is executed on the third target shutdown system. Preferably, Δ t1 ═ Δ t2 ═ Ts/3, where Ts denotes the preset on period.
As for the start-up procedure of selecting two of the three shutdown systems as the target shutdown system, reference may be made to the foregoing description, which will not be repeated here.
The zero-power grid-connected state of the inverter means that the inverter is controlled to output zero power, meanwhile, the inverter cannot be stopped and disconnected with a power grid in a fault mode, and when the zero-power grid-connected state is finished, the inverter is required to recover to set power as quickly as possible or maximum power allowed by a photovoltaic system is output by tracking a maximum power point.
As shown in fig. 11, during the zero-power grid connection period of the inverter, the two dc buses work in a staggered start mode, and at least one dc bus is always kept in an on state, so as to ensure that the input voltage of the inverter is within a preset range. At time t4, the inverter exits the zero power grid tie state and begins to output power. Because the input voltage of at least one path of the input end of the inverter is in the preset range in the zero power state, the inverter does not break down, and the inverter can rapidly output power after the time t 4. As shown in fig. 11, at time t4, the inverter starts to output power, maximum power point tracking is performed on the second dc bus, and the voltage of the second dc bus decreases from the open circuit voltage to the maximum power point voltage. When the first target shutdown system is started, the first target shutdown system can output power quickly because the inverter is already in the power output state.
Optionally, an embodiment of the present invention further provides an inverter system, including: an inverter circuit, an inverter controller, and at least two voltage control circuits,
the output end of each voltage control circuit is respectively connected with the direct current side of the inverter circuit;
the input end of each voltage control circuit is connected with at least one turn-off system;
the inversion controller is respectively connected with the inversion circuit and the control end of each voltage control circuit;
the inverter controller executes the photovoltaic turn-off system control method provided by any one of the above embodiments.
Optionally, the voltage control circuit comprises a BOOST circuit.
Optionally, an embodiment of the present invention further provides a photovoltaic turn-off system, which includes at least two turn-off systems and the inverter system provided in any of the above embodiments, wherein,
each turn-off system is respectively connected with the inverter system.
Optionally, the shutdown system includes: a plurality of photovoltaic modules, a plurality of turn-off devices and a direct current bus, wherein,
the output ends of the shut-off devices are cascaded, and the cascaded connection ports of the shut-off devices are connected with an inverter system through a direct current bus;
the input end of each breaker is respectively connected with the output end of at least one photovoltaic module corresponding to each breaker.
The embodiments of the invention are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments can be 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.
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 still within the scope of the protection of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.
Claims (14)
1. A photovoltaic turn-off system control method is applied to a photovoltaic turn-off system comprising an inverter system and at least two turn-off systems, and comprises the following steps:
determining at least two target turn-off systems in each turn-off system;
sequentially controlling the turning-on of each target turn-off system according to a preset starting interval duration so that the input voltage of the inverter system in the starting duration is in a preset range;
the preset starting interval duration is less than the duration of the on state of the turn-off system when the direct current bus voltage and/or current fluctuation is not detected;
and controlling the inverter system to start or be in a zero-power grid-connected mode.
2. The photovoltaic turn-off system control method of claim 1, wherein the sequentially controlling the turning on of each target turn-off system according to a preset start-up interval duration comprises:
controlling the ith target turn-off system to be turned on and starting timing;
if the timing time reaches the preset starting interval time, controlling the (i + 1) th target turn-off system to be turned on until all the target turn-off systems are traversed;
wherein i ∈ [1, N-1], N is the total number of the target shutdown systems.
3. The photovoltaic turn-off system control method according to claim 2, wherein the step of controlling the turning-on of any one of the target turn-off systems comprises:
and controlling the target turn-off system to be turned on according to a preset turn-on period.
4. The photovoltaic turn-off system control method of claim 3, wherein the process of controlling the target turn-on system to be turned on in any one of the preset turn-on periods comprises:
and controlling the voltage change of the direct current bus connected with the target turn-off system until the target turn-off system is turned on when the change characteristic of the voltage of the connected direct current bus meets a preset turn-on condition according to the output voltage of the target turn-off system.
5. The photovoltaic turn-off system control method according to claim 3, wherein the controlling of the voltage variation of the direct current bus to which the target turn-off system is connected includes:
and controlling the voltage of a direct current bus connected with the target turn-off system to change in a pulse waveform manner.
6. The photovoltaic turn-off system control method of claim 3, wherein the preset on interval duration is determined based on the number of the target turn-off systems and the preset on period.
7. The photovoltaic turn-off system control method according to claim 6, wherein a quotient of the preset turn-on period and the number of the target turn-off systems is used as the preset start-up interval duration.
8. A photovoltaic turn-off system control method according to claim 6, characterized in that the inverter system comprises a plurality of voltage control circuits for connecting the turn-off system;
the determining of at least two target shutdown systems in each of the shutdown systems includes:
determining available voltage control circuits in each of the voltage control circuits;
determining at least two target voltage control circuits in each of the available voltage control circuits;
and taking the shutdown system corresponding to each target voltage control circuit as a target shutdown system.
9. The photovoltaic turn-off system control method of claim 8, wherein the determining available voltage control circuits in each of the voltage control circuits comprises:
respectively detecting the bus voltage of the direct current bus corresponding to each voltage control circuit;
judging the number of the turn-off devices connected with the corresponding voltage control circuit according to the bus voltage;
and using the voltage control circuits with the number of the connected turn-off devices larger than a preset threshold value as the available voltage control circuits.
10. The photovoltaic turn-off system control method according to any one of claims 1 to 9, wherein after the inverter system is successfully started, the power corresponding to the maximum power point of the output of the photovoltaic string corresponding to each turn-off system is controlled.
11. An inversion system, comprising: an inverter circuit, an inverter controller, and at least two voltage control circuits,
the output end of each voltage control circuit is connected with the direct current side of the inverter circuit;
the input end of each voltage control circuit is connected with at least one turn-off system;
the inverter controller is respectively connected with the inverter circuit and the control end of each voltage control circuit;
the inverter controller performs the photovoltaic turn-off system control method of any one of claims 1 to 10.
12. The inverter system of claim 11, wherein the voltage control circuit comprises a BOOST circuit.
13. A photovoltaic turn-off system comprising at least two turn-off systems and the inverter system of any one of claims 11 to 12, wherein,
and each turn-off system is respectively connected with the inverter system.
14. A photovoltaic turn-off system according to claim 13, characterized in that the turn-off system comprises: a plurality of photovoltaic modules, a plurality of turn-off devices and a direct current bus, wherein,
the output ends of the shut-off devices are cascaded, and the cascaded connection ports of the shut-off devices are connected with the inverter system through the direct current bus;
and the input end of each shutoff device is respectively connected with the output end of at least one corresponding photovoltaic module.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113890400A (en) * | 2021-10-18 | 2022-01-04 | 阳光电源股份有限公司 | Inverter, control method thereof and power generation system |
| WO2023134027A1 (en) * | 2022-01-13 | 2023-07-20 | 杭州禾迈电力电子股份有限公司 | Multi-input turn-off device and control method therefor, and photovoltaic power generation system |
| WO2023202077A1 (en) * | 2022-04-20 | 2023-10-26 | 阳光电源股份有限公司 | Photovoltaic system, inverter starting method and photovoltaic energy storage system |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001161032A (en) * | 1999-12-01 | 2001-06-12 | Canon Inc | System interconnection power conditioner and power generating system using the same |
| CN103441531A (en) * | 2013-09-10 | 2013-12-11 | 上海电力学院 | Area high-permeability photovoltaic energy storage system and energy management method thereof |
| CN103872699A (en) * | 2012-12-18 | 2014-06-18 | 李木 | Variable frequency type single-phase photovoltaic inverter system and control method thereof |
| CN205005019U (en) * | 2015-10-12 | 2016-01-27 | 南京工程学院 | A test device for distributed photovoltaic power generation and network system |
| CN109038669A (en) * | 2018-08-23 | 2018-12-18 | 嘉兴爱索乐信息技术有限公司 | Realize the photovoltaic system that component level is automatically shut down |
| CN208479192U (en) * | 2018-08-20 | 2019-02-05 | 苏州阿特斯阳光电力科技有限公司 | Photovoltaic module string cutoff device and photovoltaic system |
| CN109617523A (en) * | 2018-11-28 | 2019-04-12 | 无锡尚德太阳能电力有限公司 | A kind of photovoltaic cell quick on-off system, cut-off method and starting method |
| CN109787269A (en) * | 2017-11-13 | 2019-05-21 | 丰郅(上海)新能源科技有限公司 | Photovoltaic module rapidly switches off the method for restarting after system and shutdown |
| CN109802556A (en) * | 2017-11-17 | 2019-05-24 | 丰郅(上海)新能源科技有限公司 | The starting method of photovoltaic generating system and inverter with photovoltaic DC-to-AC converter |
| US20200266650A1 (en) * | 2019-02-19 | 2020-08-20 | Samsung Electronics Co., Ltd. | Electronic device and method for controlling wireless charging |
| CN111934352A (en) * | 2020-10-09 | 2020-11-13 | 浙江英达威芯电子有限公司 | Photovoltaic system, control method of turn-off device of photovoltaic system and switch control device |
| CN112234649A (en) * | 2020-10-15 | 2021-01-15 | 珠海格力电器股份有限公司 | Self-adaptive photovoltaic power supply system, control method thereof and air conditioning unit |
| CN112821458A (en) * | 2021-03-23 | 2021-05-18 | 阳光电源股份有限公司 | Photovoltaic rapid turn-off system and control method thereof |
-
2021
- 2021-06-22 CN CN202110688940.4A patent/CN113270893B/en active Active
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001161032A (en) * | 1999-12-01 | 2001-06-12 | Canon Inc | System interconnection power conditioner and power generating system using the same |
| CN103872699A (en) * | 2012-12-18 | 2014-06-18 | 李木 | Variable frequency type single-phase photovoltaic inverter system and control method thereof |
| CN103441531A (en) * | 2013-09-10 | 2013-12-11 | 上海电力学院 | Area high-permeability photovoltaic energy storage system and energy management method thereof |
| CN205005019U (en) * | 2015-10-12 | 2016-01-27 | 南京工程学院 | A test device for distributed photovoltaic power generation and network system |
| CN109787269A (en) * | 2017-11-13 | 2019-05-21 | 丰郅(上海)新能源科技有限公司 | Photovoltaic module rapidly switches off the method for restarting after system and shutdown |
| CN109802556A (en) * | 2017-11-17 | 2019-05-24 | 丰郅(上海)新能源科技有限公司 | The starting method of photovoltaic generating system and inverter with photovoltaic DC-to-AC converter |
| CN208479192U (en) * | 2018-08-20 | 2019-02-05 | 苏州阿特斯阳光电力科技有限公司 | Photovoltaic module string cutoff device and photovoltaic system |
| CN109038669A (en) * | 2018-08-23 | 2018-12-18 | 嘉兴爱索乐信息技术有限公司 | Realize the photovoltaic system that component level is automatically shut down |
| CN109617523A (en) * | 2018-11-28 | 2019-04-12 | 无锡尚德太阳能电力有限公司 | A kind of photovoltaic cell quick on-off system, cut-off method and starting method |
| US20200266650A1 (en) * | 2019-02-19 | 2020-08-20 | Samsung Electronics Co., Ltd. | Electronic device and method for controlling wireless charging |
| CN111934352A (en) * | 2020-10-09 | 2020-11-13 | 浙江英达威芯电子有限公司 | Photovoltaic system, control method of turn-off device of photovoltaic system and switch control device |
| CN112234649A (en) * | 2020-10-15 | 2021-01-15 | 珠海格力电器股份有限公司 | Self-adaptive photovoltaic power supply system, control method thereof and air conditioning unit |
| CN112821458A (en) * | 2021-03-23 | 2021-05-18 | 阳光电源股份有限公司 | Photovoltaic rapid turn-off system and control method thereof |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113890400A (en) * | 2021-10-18 | 2022-01-04 | 阳光电源股份有限公司 | Inverter, control method thereof and power generation system |
| CN113890400B (en) * | 2021-10-18 | 2024-05-14 | 阳光电源股份有限公司 | Inverter, control method thereof and power generation system |
| WO2023134027A1 (en) * | 2022-01-13 | 2023-07-20 | 杭州禾迈电力电子股份有限公司 | Multi-input turn-off device and control method therefor, and photovoltaic power generation system |
| WO2023202077A1 (en) * | 2022-04-20 | 2023-10-26 | 阳光电源股份有限公司 | Photovoltaic system, inverter starting method and photovoltaic energy storage system |
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