CN112821866B - Photovoltaic rapid turn-off system and control method thereof - Google Patents
Photovoltaic rapid turn-off system and control method thereof Download PDFInfo
- Publication number
- CN112821866B CN112821866B CN202110333462.5A CN202110333462A CN112821866B CN 112821866 B CN112821866 B CN 112821866B CN 202110333462 A CN202110333462 A CN 202110333462A CN 112821866 B CN112821866 B CN 112821866B
- Authority
- CN
- China
- Prior art keywords
- direct current
- photovoltaic
- inverter system
- bus
- inverter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 67
- 239000003990 capacitor Substances 0.000 claims description 19
- 230000009471 action Effects 0.000 claims description 11
- 238000010248 power generation Methods 0.000 abstract description 10
- 230000009467 reduction Effects 0.000 abstract description 5
- 238000001514 detection method Methods 0.000 description 9
- 230000008569 process Effects 0.000 description 8
- 230000005540 biological transmission Effects 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005192 partition Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 230000004913 activation Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
- H02S50/00—Monitoring or testing of PV systems, e.g. load balancing or fault identification
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention provides a photovoltaic fast turn-off system and a control method thereof.A direct current bus of the photovoltaic fast turn-off system is not directly disturbed by an electric signal when the inverter system judges that the photovoltaic fast turn-off system does not need to enter a preset safety state, but the current or the power on the direct current bus is judged whether to exceed a corresponding preset threshold value or not; if the direct current bus with the current or the power exceeding the corresponding preset threshold exists, stopping applying the electric signal disturbance to the corresponding direct current bus; and then each shutoff device of the photovoltaic quick turn-off system respectively detects the electrical parameter of the shutoff device, and when the telecommunication of the direct current bus connected with the shutoff device is judged to meet the preset condition according to the electrical parameter, the shutoff device enters or maintains the on state. The control method does not apply disturbance to the direct current bus indiscriminately, and particularly does not apply disturbance when the current or power on the direct current bus exceeds a corresponding threshold value; therefore, compared with the undifferentiated continuous disturbance in the prior art, the control method can avoid the reduction of the system power generation amount and improve the system efficiency.
Description
Technical Field
The invention relates to the technical field of photovoltaic power generation, in particular to a photovoltaic quick turn-off system and a control method thereof.
Background
In consideration of safety of photovoltaic operation and maintenance personnel, a photovoltaic quick turn-off system in the field needs to ensure that the output of a photovoltaic string is in a safe state under the condition that any element or module has a fault; in order to achieve the purpose of output safety under the fault, a heartbeat method is generally adopted in the prior art, and specifically, the method comprises the following steps: continuously sending an on signal to a shutoff device in the photovoltaic shutoff system to maintain the on state of the shutoff device; and when the switching-on signal disappears, the turn-off device controls the output of the turn-off device to be in a limited output state, and the corresponding photovoltaic module is switched off.
However, this solution requires a separate transmission device for the activation signal to be added to each group of strings, which increases the cost of the system; moreover, the open signal transmitted by the communication mode is easy to attenuate or interfere, and the reliability is low; therefore, in the prior art, a method for starting a photovoltaic fast turn-off system is also provided, in which a current or voltage disturbance is continuously applied to a dc bus of an inverter system to maintain the turn-on of a turn-off device, so that the turn-off device is not required to continuously receive a heartbeat signal sent by a sending device, the overall cost of the photovoltaic fast turn-off system is reduced, and meanwhile, the attenuation and interference easily occurring in communication transmission are avoided.
However, continuous parameter fluctuation on the direct current bus can reduce the system power generation amount and influence the system efficiency.
Disclosure of Invention
In view of this, the invention provides a photovoltaic fast turn-off system and a control method thereof, so as to avoid reduction of system power generation and improve system efficiency.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
the first aspect of the embodiments of the present invention provides a control method for a photovoltaic fast turn-off system, including:
the inverter system of the photovoltaic quick turn-off system judges whether the photovoltaic quick turn-off system needs to enter a preset safety state;
if the photovoltaic quick turn-off system does not need to enter a preset safety state, the inverter system judges whether the current or the power on the direct current bus of the inverter system exceeds a corresponding preset threshold value;
if the current or the power of the direct current bus exceeds the corresponding preset threshold value, the inverter system stops applying the electric signal disturbance to the corresponding direct current bus;
each shut-off device of the photovoltaic rapid shut-off system detects own electrical parameters respectively and judges whether the electrical signals of the direct current bus connected with the shut-off device meet preset conditions or not according to the electrical parameters;
and if the electric signal of the direct current bus connected with the on-off device meets the preset condition, the on-off device enters or maintains the on state.
Preferably, after the inverter system determines whether the current or power on the dc bus thereof exceeds a corresponding preset threshold, the method further includes:
and if the current or the power of the direct current bus does not exceed the corresponding preset threshold value, the inverter system applies electric signal disturbance to the corresponding direct current bus.
Preferably, if the inverter system is a single-stage inverter system, the inverter system applies an electric signal disturbance to a corresponding dc bus, including:
when the output current of the inverter system is fed into a power grid, the action of a switching tube of an inverter circuit in the inverter system is controlled, so that the bus capacitor in the inverter system is repeatedly charged and discharged, and the electric signal on a direct current bus in the inverter system is disturbed.
Preferably, if the inverter system is a two-stage inverter system, the inverter system applies an electric signal disturbance to a corresponding dc bus, including:
when the output current of the inverter system is fed into a power grid, the action of a switching tube of an inverter circuit in the inverter system is controlled, so that a bus capacitor in the inverter system is repeatedly charged and discharged; then, each Boost circuit in the inverter system is controlled to be directly connected, so that the electric signals on all the direct current buses are disturbed; alternatively, the first and second electrodes may be,
when the output current of the inverter system is fed into a power grid, the action of a switching tube of a corresponding Boost circuit in the inverter system is controlled, so that the bus capacitor is repeatedly charged and discharged, and the disturbance of an electric signal corresponding to a direct current bus is caused.
Preferably, the electrical signal disturbance is:
continuous perturbation obtained after continuous application; alternatively, the first and second electrodes may be,
intermittent disturbance is periodically applied, and the application period of the intermittent disturbance is less than the rapid turn-off time of the photovoltaic rapid turn-off system.
Preferably, the electrical signal perturbation is: a voltage perturbation signal and/or a current perturbation signal, or a power perturbation signal.
Preferably, the determining whether the electrical signal of the dc bus connected to the dc bus meets a preset condition according to the electrical parameter includes:
judging whether the current or the power of a direct current bus connected with the direct current bus exceeds a corresponding preset threshold value or not according to the electrical parameters;
and if the current or the power of the direct current bus connected with the direct current bus exceeds a corresponding preset threshold value, judging that the electric signal meets the preset condition.
Preferably, the method further includes, after determining whether the electrical signal of the dc bus meets a preset condition according to the electrical parameter and determining whether the current or the power of the dc bus exceeds a corresponding preset threshold according to the electrical parameter:
if the current or the power of the direct current bus connected with the direct current bus does not exceed the corresponding preset threshold value, judging whether the electrical parameters of the direct current bus fluctuate or not;
and if the electric parameters fluctuate, judging that the electric signals meet the preset conditions.
Preferably, the determining whether the electrical parameter fluctuates includes:
judging whether the input/output voltage and/or current of the device fluctuates or not;
and if the voltage and/or the current input/output by the electronic device fluctuates, judging that the electric signal fluctuates.
Preferably, after the inverter system of the photovoltaic fast turn-off system determines whether the photovoltaic fast turn-off system needs to enter a preset safety state, the method further includes:
and if the photovoltaic quick turn-off system needs to enter a preset safe state, the inverter system stops outputting power.
Preferably, after determining whether the electrical signal of the dc bus connected to the dc bus meets the preset condition according to the electrical parameter, the method further includes:
and if the electric signal of the direct current bus connected with the breaker does not meet the preset condition, the breaker enters or maintains the off state.
In another aspect, the present invention further provides a photovoltaic fast turn-off system, including: the system comprises an inverter system and at least one photovoltaic string; wherein:
in the same photovoltaic group string, the input end of each breaker is connected with a corresponding photovoltaic module, the output ends of the breakers are connected in series, and the two ends after being connected in series are used as the two ends of the photovoltaic group string and are connected with corresponding direct current ports of the inverter system through corresponding direct current buses;
the alternating current of the inverter system is connected to a power grid;
the inverter system is combined with each breaker to jointly execute the control method of the photovoltaic rapid turn-off system in any one of the above paragraphs.
Preferably, if the inverter system is a single-stage inverter system, the inverter system includes: the device comprises a controller, an inverter circuit, a bus capacitor and at least one driving circuit; wherein:
the input end of the inverter circuit is respectively connected with the two ends of the bus capacitor through a direct current bus of the inverter system;
the output end of the inverter circuit is used as the alternating current side of the inverter system;
the output end of the driving circuit is connected with the control end of each switching tube in the inverter circuit;
each driving circuit is controlled by the controller.
Preferably, if the inverter system is a two-stage inverter system, the inverter system further includes: at least one Boost circuit; wherein:
the input end of the Boost circuit is used as a pair of direct current ports of the inverter system, and two poles of the output end of the Boost circuit are correspondingly connected with two ends of the bus capacitor;
and the controller is connected with the control ends of the switching tubes in the Boost circuit through the corresponding driving circuits.
Preferably, the inverter system is a single-phase system, or a three-phase system.
According to the control method of the photovoltaic quick turn-off system, when the inverter system judges that the photovoltaic quick turn-off system does not need to enter a preset safe state, electric signal disturbance is not directly applied to a direct current bus of the inverter system, and whether the current or the power on the direct current bus exceeds a corresponding preset threshold value is judged; if the direct current bus with the current or the power exceeding the corresponding preset threshold exists, stopping applying the electric signal disturbance to the corresponding direct current bus; then each shut-off device of the photovoltaic rapid shut-off system respectively detects the electrical parameter of the shut-off device, and judges whether the electrical signal of the direct current bus connected with the shut-off device meets the preset condition or not according to the electrical parameter; and if the electric signal of the direct current bus connected with the direct current bus meets the preset condition, entering or maintaining the on state. That is, the control method does not apply disturbance to the dc bus indiscriminately, and particularly does not apply disturbance when the current or power on the dc bus exceeds the corresponding threshold; therefore, compared with the undifferentiated continuous disturbance in the prior art, the control method can avoid the reduction of the power generation amount of the system and improve the efficiency of the system.
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 is a flowchart of a control method of a photovoltaic fast turn-off system according to an embodiment of the present invention;
fig. 2 is another flowchart of a control method of a photovoltaic fast turn-off system according to an embodiment of the present invention;
fig. 3 is a partial flowchart of a control method of a photovoltaic fast turn-off system according to an embodiment of the present invention;
fig. 4 to fig. 6 are three structural diagrams of a photovoltaic fast turn-off system according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, 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 invention.
In this application, 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.
The invention provides a control method of a photovoltaic quick turn-off system, which is used for avoiding the reduction of the power generation capacity of the system and improving the efficiency of the system.
As shown in fig. 4, the photovoltaic fast turn-off system specifically includes: an inverter system 101 and at least one photovoltaic string 102; in the same photovoltaic group string 102, the input end of each breaker is connected with a corresponding photovoltaic module, the output ends of each breaker are connected in series, and the two ends after series connection are used as the two ends of the photovoltaic group string 102 and are connected with corresponding direct current ports of the inverter system 101 through corresponding direct current buses; the alternating current of the inverter system 101 is connected to a power grid; fig. 1 shows a flowchart of the inverter system 101, which is used in combination with each shutdown device to jointly execute a control method, and specifically includes:
s101, an inverter system of the photovoltaic quick turn-off system judges whether the photovoltaic quick turn-off system needs to enter a preset safety state.
In practical application, the preset safety state means that each shut-off device limits the output of electric energy of the corresponding photovoltaic module, so that the voltage on the direct current bus of the corresponding photovoltaic module is smaller than a limit value within a certain preset time, and further, any potential safety hazard cannot be brought. For specific contents, reference may be made to the prior art, which is not described herein in detail.
If the photovoltaic fast turn-off system does not need to enter the preset safe state, step S102 is executed.
S102, the inverter system judges whether the current or the power on the direct current bus exceeds a corresponding preset threshold value.
The direct current side of the inverter system can only have one direct current bus, such as a single-stage inverter system, and a power loop of the inverter system is only provided with a first-stage inverter circuit, and at the moment, the direct current bus is also a direct current bus of the inverter system; the direct current side of the inverter circuit can also be provided with a plurality of direct current buses, such as a two-stage inverter system, and the input end of each Boost circuit at the front stage of the inverter circuit is provided with a corresponding direct current bus. When the electrical parameter of the on-off device connected to the dc bus is large, for example, when the input/output current and/or voltage of the on-off device is large, the corresponding parameter on the dc bus is also large.
Because the voltage sampling precision and the current sampling precision of the turn-off device are limited, the accuracy of a detection result is lower when small current or small voltage is detected; and when the device detects large current or large voltage, namely the detected current or voltage is larger than the corresponding detection threshold value, the accuracy of the detection result can meet the relevant requirements. Therefore, when the current or power of the direct current bus connected with the breaker is large, namely when the electrical parameter of the breaker is large, the steady-state value of the electrical parameter can be directly detected, and the detection result with the accuracy meeting the requirement is obtained; tracing back, namely, the fact that whether the current or the power on the direct current bus of the inverter system exceeds a corresponding preset threshold value or not can be judged.
For all direct current buses of the inverter system, the direct current buses can be in the same state at the same time, for example, the environment difference of each photovoltaic group string is not large; of course, the situation that the states of all the dc buses are different at the same time is not excluded, for example, when a certain photovoltaic string or a few photovoltaic strings are shielded, the current or power on the corresponding dc bus is significantly lower than that of other dc buses. Regardless of the actual situation, step S103 is executed as long as there is a dc bus with current or power exceeding the corresponding preset threshold.
And S103, stopping applying the electric signal disturbance to the corresponding direct current bus by the inverter system.
From the above analysis, if the current or power on a certain dc bus exceeds the corresponding threshold, the electrical parameter of the shut-off device will be correspondingly greater than the corresponding detection threshold, and at this time, the shut-off device can directly detect the steady-state value of the electrical parameter, so that the inverter system is no longer required to apply the electrical signal disturbance to the corresponding dc bus in the early stage.
After the inverter system completes the actions required to be executed, step S104 is executed.
S104, each shut-off device of the photovoltaic rapid shut-off system detects own electrical parameters respectively, and judges whether the electrical signals of the direct current bus connected with the shut-off devices meet preset conditions or not according to the electrical parameters.
It should be noted that the input/output voltage of the turn-off device is in a proportional relationship with the voltage on the dc bus connected thereto, and the current on the dc bus is the same as the input/output current of each turn-off device connected thereto; therefore, by detecting own electrical parameters, such as input/output current and/or voltage, of each shut-off device, a condition that whether an electrical signal on a direct current bus connected with the shut-off device meets a preset condition, such as whether the current or the power exceeds a corresponding preset threshold value, can be obtained; and if the current or the power of the direct current bus connected with the turn-off device exceeds a corresponding preset threshold value, judging that the electric signal meets a preset condition.
If the electrical signal of the dc bus meets the predetermined condition, step S105 is executed.
And S105, the turn-off device enters or maintains the on state.
If the current state of the turn-off device is off, controlling the turn-on state of the turn-off device when the turn-off device judges that the electric signal of the direct current bus connected with the turn-off device meets the preset condition; if the current state is on, the controller controls the controller to maintain the on state when the controller judges that the electric signal of the direct current bus connected with the controller meets the preset condition. And under the condition of opening, the photovoltaic module connected with the photovoltaic module can be connected into an inverter system.
As can be obtained from the above, according to the control method of the photovoltaic fast turn-off system provided in this embodiment, when the inverter system determines that the photovoltaic fast turn-off system does not need to enter the preset safe state, the inverter system does not directly apply electrical signal disturbance to the dc bus thereof, but first determines whether the current or power on the dc bus thereof exceeds the corresponding preset threshold; if the direct current bus with the current or the power exceeding the corresponding preset threshold exists, stopping applying the electric signal disturbance to the corresponding direct current bus; then each shut-off device of the photovoltaic rapid shut-off system respectively detects the electrical parameter of the shut-off device, and judges whether the electrical signal of the direct current bus connected with the shut-off device meets the preset condition or not according to the electrical parameter; and if the electric signal of the direct current bus connected with the direct current bus meets the preset condition, entering or maintaining the on state. That is, the control method does not apply disturbance to the dc bus indiscriminately, especially when the current or power on the dc bus exceeds the corresponding threshold value; therefore, compared with the undifferentiated continuous disturbance in the prior art, the control method can avoid the reduction of the system power generation amount and improve the system efficiency.
On the basis of the above embodiment, after the step S102, the inverter system determines whether the current or power on the dc bus of the inverter system exceeds the corresponding preset threshold, the method for controlling a photovoltaic fast turn-off system further includes: if there is a dc bus whose current or power does not exceed the corresponding preset threshold, it indicates that the electrical parameter of the corresponding shutdown device cannot exceed its corresponding detection threshold, and at this time, it is necessary to increase the disturbance artificially to improve the reliability of the shutdown device detection, and therefore, step S1031 needs to be executed, specifically referring to fig. 2.
And S1031, applying the electric signal disturbance to the corresponding direct current bus by the inverter system.
For a single-stage inverter system, the specific process of applying the electric signal disturbance can be that when the output current of the inverter system is fed into a power grid, the action of a switching tube in an inverter circuit is controlled, so that the bus capacitor in the inverter system is repeatedly charged and discharged, the electric signal on a direct current bus is disturbed, and the direct application of the electric signal disturbance to the direct current bus serving as the direct current bus is realized.
For the two-stage inverter system, the specific process of applying the electric signal disturbance can be that when the output current of the inverter system is fed into a power grid, the action of a switching tube in an inverter circuit is controlled, so that the bus capacitor in the inverter system is repeatedly charged and discharged, the electric signal on a direct current bus is disturbed, and then the Boost circuit is directly connected to apply the electric signal disturbance to each direct current bus, so that the electric signal disturbance which is the same for all the direct current buses is realized.
In addition, for the two-stage inverter system, the specific process of applying the electric signal disturbance to the two-stage inverter system may also be that when the output current of the inverter system is fed into the power grid, the action of a switching tube in a corresponding Boost circuit is controlled, so that the bus capacitor is repeatedly charged and discharged, and the electric signal corresponding to the direct current bus is disturbed, so that the electric signal disturbance to the part of the direct current bus is realized; and for the other part of Boost circuits, because the corresponding direct current buses do not need to apply electric signal disturbance, the actions do not need to be carried out, and only normal PWM output is needed.
It should be noted that the electrical signal disturbance may be a continuous disturbance obtained after continuous application, or may be an intermittent disturbance applied periodically; and when the electrical signal disturbance is periodically applied to the corresponding direct current bus, the application period of the electrical signal disturbance needs to be shorter than the rapid turn-off time of the photovoltaic rapid turn-off system, namely, each turn-off device is ensured not to be turned off by mistake.
In practical application, the electrical signal disturbance may be a current disturbance signal, a voltage disturbance signal, or a disturbance signal combining voltage and current, or a power disturbance signal, which is determined by a practical application scenario, and is not specifically limited herein.
The embodiment provides a method for disturbing intervals, which ensures the on state of a turn-off device by applying electric signal disturbance only when the power or current on a direct current bus is small; when the power or current on the direct current bus is large, the steady state value of the electrical parameter of the turn-off device is detected directly without applying electrical signal disturbance, and therefore the power generation loss caused by the electrical signal disturbance in a full power range is avoided.
In addition, in practical application, referring to fig. 2, after the step S101, after the inverter system of the photovoltaic fast turn-off system determines whether the photovoltaic fast turn-off system needs to enter the preset safe state, the control method further includes:
if the photovoltaic fast turn-off system needs to enter the preset safe state, step S1021 is executed.
And S1021, stopping outputting power by the inverter system.
After step S1021, step S103, and step S1031, the process proceeds to step S104.
For the control method of the photovoltaic fast turn-off system described in the foregoing embodiment, preferably, in this embodiment, a specific implementation form is given for determining whether the electrical signal of the dc bus connected to the control method satisfies a preset condition according to the electrical parameter in step S104, and refer to fig. 3:
s201, judging whether the current or the power of the direct current bus connected with the direct current bus exceeds a corresponding preset threshold value according to the electrical parameters.
If the current or power of the dc bus itself exceeds the corresponding preset threshold, step S202 is executed. If the current or power of the dc bus does not exceed the corresponding predetermined threshold, step S203 is executed.
S202, judging that the electric signal meets a preset condition.
And S203, judging whether the self electrical parameter fluctuates.
The judging process may specifically be: judging whether the input/output voltage and/or current of the device fluctuates or not; and if the voltage and/or the current input/output by the device fluctuates, judging that the electrical parameters of the device fluctuate.
If the electrical parameter fluctuates, step S202 is also executed to determine that the electrical signal satisfies the preset condition.
That is, in practical application, the shutdown device needs to detect the voltage and/or current of the connected dc bus according to its own electrical parameter; then judging whether the current or the power of the breaker is larger than a corresponding preset threshold value, if so, maintaining or controlling the on-off of the breaker; and if the current is less than or equal to the corresponding preset threshold value, the turn-off device detects voltage or current disturbance, if the disturbance exists, the turn-off device is maintained or controlled to be turned on, and otherwise, the turn-off device is controlled or maintained to be turned off.
In addition, in practical applications, referring to fig. 2, after determining whether the electrical signal of the dc bus connected to the control method satisfies the preset condition according to the electrical parameter in step S104, the control method further includes:
if the electrical signal of the dc bus does not satisfy the predetermined condition, step S1051 is executed.
And S1051, the turn-off device enters or maintains the turn-off state.
Based on the above embodiments, this embodiment provides a specific complete example to explain the principle of inter-partition control of the control method:
when the inversion system judges that the current direct current buses do not need to enter the preset safety state, the inversion system can judge the power/current on the current direct current buses, if the power/current on the current direct current buses is larger than the corresponding preset threshold value, the system does not need to apply electric signal disturbance, and each shutoff device can control/maintain the on-state only by detecting a steady-state value; if the current power/current on each direct current bus is smaller than or equal to the corresponding preset threshold value, the current and the power are both small, the turn-off device cannot correctly identify a steady-state value, and the inverter system needs to apply electric signal disturbance at the moment, so that the corresponding turn-off device can maintain/control the turn-on of the turn-off device; the electrical signal perturbation may be a continuous perturbation or an intermittent perturbation.
And if the inverter system judges that the photovoltaic quick turn-off system needs to enter a preset safety state, the inverter system stops outputting power. The photovoltaic module judges whether the voltage and/or the current of the direct current bus connected with the photovoltaic module meet the preset conditions or not according to the electrical parameters of the photovoltaic module, and controls/maintains self turn-off if the voltage and/or the current of the direct current bus do not meet the preset conditions.
In this embodiment, when the power/current on the dc bus is small, the inverter system applies disturbance; when the power/current on the direct current bus is larger, the inverter does not apply disturbance any more; that is, the disturbance does not exist in the full power range, but exists only in the small power/current, thereby achieving the purpose of improving the power generation amount. In addition, in this embodiment, the turn-off device does not perform disturbance detection in the full power range, but detects the relationship between the disturbance value and the corresponding threshold value only when the power is small; when the power is large, the inverter system does not apply disturbance any more, and the shutoff device only needs to detect the steady-state value of the voltage or the current and does not detect the disturbance value. Wherein, the disturbance value refers to a change value caused by disturbance, and the steady state value is relative to the disturbance value; when the current or the power is larger than the threshold value, detecting a steady state value because the steady state value is larger and the turn-off device can be accurately detected, and further judging whether the turn-off device needs to be maintained or controlled to be turned on; when the current or the power is smaller than the threshold value, a disturbance value is detected, because the steady state value is smaller at the moment, the detection of the turn-off device can generate misjudgment, so that the disturbance value is detected instead, if the disturbance exists, the turn-off device is maintained or controlled to be switched on, and if the disturbance does not exist, the turn-off device is maintained or controlled to be switched off.
Another embodiment of the present invention further provides a photovoltaic fast turn-off system, referring to fig. 4, including: an inverter system 101 and at least one photovoltaic string 102 (only one is shown as an example); wherein:
in the same photovoltaic string 102, the input end of each breaker is connected to a corresponding photovoltaic module, as shown in fig. 4, the input end of one breaker is connected to one corresponding photovoltaic module, or two photovoltaic modules (not shown) may be connected; the output ends of the shut-off devices are connected in series, and the two ends after being connected in series are used as the two ends of the photovoltaic string 102 and are connected with the corresponding direct current ports of the inverter system 101 through the corresponding direct current buses; the ac side of the inverter system 101 is connected to the grid. And then the inverter system 101 is combined with each breaker to jointly execute any control method of the photovoltaic rapid turn-off system provided by the above embodiments.
The inverter system 101 may be a single-stage inverter, and the specific structure thereof may be as shown in fig. 5, including: the controller 310, the inverter circuit 320, the bus capacitor C1 and the at least one driving circuit 330; wherein:
the input end of the inverter circuit 320 is respectively connected with two ends of a bus capacitor C1 through a direct current bus of the inverter system 101; the output end of the inverter circuit 320 serves as the ac side of the inverter; the output end of the driving circuit 330 is connected with the control end of each switching tube in the inverter circuit 320; the controller 310 is communicatively connected to each driving circuit 330, and is configured to send a control command to each driving circuit 330, so as to control each driving circuit 330 to output a driving signal to each switching tube in the inverter system 101. It should be noted that the topology of the inverter circuit 320 may be an H-bridge as shown in fig. 5, that is, the inverter circuit 320 includes two parallel-connected bridge arms, two ends of the parallel-connected bridge arms are used as input ends of the bridge arms, and a midpoint of each bridge arm is used as an output end of the inverter circuit 320; at this time, the inverter system 101 is a single-phase system; in practical applications, the inverter system 101 may also be a three-phase system, that is, the topology of the inverter circuit 320 may also be a three-phase full-bridge structure (not shown); depending on the specific application environment, are all within the scope of the embodiments of the present invention.
It should be noted that the inverter system 101 may also be a two-stage inverter, that is, based on the above structure, the inverter system further includes: at least one Boost circuit 410; for example, a schematic structural diagram is shown in fig. 6; when a plurality of Boost circuits are provided, the output ends of the Boost circuits 410 are connected in parallel to the dc bus, that is, the two ends of the bus capacitor C1, which is not described again. The input end of the Boost circuit 410 is used as a pair of direct current ports of the inverter system 101 and connected with corresponding direct current buses, and two poles of the output end of the Boost circuit 410 are correspondingly connected with two ends of a bus capacitor C1; the controller 310 is connected to the control terminals of the switching tubes in the Boost circuit 410 through the corresponding driving circuits 330.
In practical applications, the switching transistors in the inverter circuit 320 and the Boost circuit 410 may be controlled by separate driving circuits 330, or may be controlled by an integrated driving circuit 330 (not shown).
The inverter system 101 in the photovoltaic rapid turn-off system may be a single-phase system as shown in fig. 4 to 6, or may be a three-phase system (not shown); the applied electrical signal disturbances are: a voltage perturbation signal and/or a current perturbation signal, or a power perturbation signal.
It should be noted that the fast turn-off method of the component proposed in the prior art requires continuous disturbance of the dc bus voltage or current, and the continuous disturbance affects the system power generation. According to the photovoltaic fast turn-off system provided by the embodiment, through the partition type disturbance method provided by the embodiment, the inverter system 101 detects the voltage or current of the direct current bus, and when the detected direct current side current or power is larger than a preset threshold value, no disturbance is applied; when the direct current side current or power is detected to be less than or equal to the threshold value, voltage or current disturbance is applied. And for the shutdown: the turn-off device detects the direct-current voltage and/or direct current of the input end/output end of the turn-off device, and when the detected power or current is larger than a threshold value, the turn-off device is maintained or controlled to be switched on; when the detected power or current is smaller than the threshold value, the judgment is carried out by detecting the voltage or current disturbance, namely, when the disturbance exists, the on of the turn-off device is maintained or controlled, and when the disturbance does not exist, the turn-off device is controlled or maintained to be turned off.
The rest of the principle is the same as the above embodiments, and is not described in detail here.
The same and similar parts among the various embodiments in the present specification are referred to each other, and each embodiment focuses on differences from other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the above description of the disclosed embodiments, the features described in the embodiments in this specification may be replaced or combined with each other to enable those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (14)
1. A control method of a photovoltaic rapid turn-off system is characterized by comprising the following steps:
the inverter system of the photovoltaic quick turn-off system judges whether the photovoltaic quick turn-off system needs to enter a preset safety state;
if the photovoltaic quick turn-off system does not need to enter a preset safety state, the inverter system judges whether the current or the power on the direct current bus of the inverter system exceeds a corresponding preset threshold value;
if the current or the power of the direct current bus exceeds the corresponding preset threshold value, the inverter system stops applying the electric signal disturbance to the corresponding direct current bus;
each shut-off device of the photovoltaic rapid turn-off system detects an electrical parameter of the shut-off device, and judges whether an electrical signal of a direct current bus connected with the shut-off device meets a preset condition or not according to the electrical parameter, wherein when the electrical signal on the direct current bus connected with the shut-off device exceeds a preset threshold value, the shut-off device can detect a steady state value of the electrical parameter of the shut-off device;
if the electric signal of the direct current bus connected with the on-off device meets the preset condition, the on-off device enters or maintains an on state;
and if the current or the power of the direct current bus does not exceed the corresponding preset threshold value, the inverter system applies electric signal disturbance to the corresponding direct current bus.
2. The method for controlling a photovoltaic rapid shutdown system according to claim 1, wherein if the inverter system is a single-stage inverter system, the inverter system applies an electrical signal disturbance to the corresponding dc bus, including:
when the output current of the inverter system is fed into a power grid, the action of a switching tube of an inverter circuit in the inverter system is controlled, so that the bus capacitor in the inverter system is repeatedly charged and discharged, and the electric signal on a direct current bus in the inverter system is disturbed.
3. The control method of a photovoltaic rapid turn-off system according to claim 1, wherein if the inverter system is a two-stage inverter system, the inverter system applies an electrical signal disturbance to a corresponding dc bus, comprising:
when the output current of the inverter system is fed into a power grid, the action of a switching tube of an inverter circuit in the inverter system is controlled, so that a bus capacitor in the inverter system is repeatedly charged and discharged; then, each Boost circuit in the inverter system is controlled to be directly connected, so that the electric signals on all the direct current buses are disturbed; alternatively, the first and second electrodes may be,
when the output current of the inverter system is fed into a power grid, the action of a switching tube of a corresponding Boost circuit in the inverter system is controlled, so that the bus capacitor is repeatedly charged and discharged, and the disturbance of an electric signal corresponding to a direct current bus is caused.
4. The control method of a photovoltaic rapid shutdown system according to claim 1, characterized in that the electrical signal disturbance is:
continuous perturbation obtained after continuous application; alternatively, the first and second electrodes may be,
intermittent disturbance is periodically applied, and the application period of the intermittent disturbance is less than the rapid turn-off time of the photovoltaic rapid turn-off system.
5. The control method of a photovoltaic rapid shutdown system according to claim 1, characterized in that the electrical signal disturbance is: a voltage perturbation signal and/or a current perturbation signal, or a power perturbation signal.
6. The control method of the photovoltaic rapid turn-off system according to any one of claims 1 to 5, wherein judging whether the electrical signal of the DC bus connected to the control method meets a preset condition according to the electrical parameter comprises:
judging whether the current or the power of a direct current bus connected with the direct current bus exceeds a corresponding preset threshold value or not according to the electrical parameters;
and if the current or the power of the direct current bus connected with the direct current bus exceeds a corresponding preset threshold value, judging that the electric signal meets the preset condition.
7. The method for controlling a photovoltaic fast turn-off system according to claim 6, wherein the method further comprises, after determining whether an electrical signal of the dc bus connected to the photovoltaic fast turn-off system satisfies a preset condition according to the electrical parameter and determining whether a current or a power of the dc bus connected to the photovoltaic fast turn-off system exceeds a corresponding preset threshold according to the electrical parameter:
if the current or the power of the direct current bus connected with the direct current bus does not exceed the corresponding preset threshold value, judging whether the electrical parameters of the direct current bus fluctuate or not;
and if the electric parameters fluctuate, judging that the electric signals meet the preset conditions.
8. The control method of the photovoltaic rapid turn-off system according to claim 7, wherein the step of judging whether the electrical parameter fluctuates comprises the following steps:
judging whether the input/output voltage and/or current of the device fluctuates or not;
and if the voltage and/or the current input/output by the electronic device fluctuates, judging that the electric signal fluctuates.
9. The control method of the photovoltaic rapid turn-off system according to any one of claims 1 to 5, wherein after the inverter system of the photovoltaic rapid turn-off system determines whether the photovoltaic rapid turn-off system needs to enter a preset safe state, the method further comprises:
and if the photovoltaic quick turn-off system needs to enter a preset safe state, the inverter system stops outputting power.
10. The control method of the photovoltaic rapid turn-off system according to any one of claims 1 to 5, after determining whether the electrical signal of the DC bus connected to the control method meets the preset condition according to the electrical parameter, the method further comprises:
and if the electric signal of the direct current bus connected with the breaker does not meet the preset condition, the breaker enters or maintains the off state.
11. A photovoltaic rapid shutdown system, comprising: the system comprises an inverter system and at least one photovoltaic string; wherein:
in the same photovoltaic group string, the input end of each breaker is connected with a corresponding photovoltaic module, the output ends of the breakers are connected in series, and the two ends after being connected in series are used as the two ends of the photovoltaic group string and are connected with corresponding direct current ports of the inverter system through corresponding direct current buses;
the alternating current of the inverter system is connected to a power grid;
the inverter system and each of the shutdown devices jointly execute the control method of the photovoltaic rapid turn-off system according to any one of claims 1 to 10.
12. The photovoltaic rapid shutdown system of claim 11, wherein if the inverter system is a single-stage inverter system, the inverter system comprises: the device comprises a controller, an inverter circuit, a bus capacitor and at least one driving circuit; wherein:
the input end of the inverter circuit is respectively connected with two ends of the bus capacitor through a direct current bus of the inverter system;
the output end of the inverter circuit is used as the alternating current side of the inverter system;
the output end of the driving circuit is connected with the control end of each switching tube in the inverter circuit;
each driving circuit is controlled by the controller.
13. The photovoltaic rapid shutdown system of claim 12, wherein if the inverter system is a two-stage inverter system, the inverter system further comprises: at least one Boost circuit; wherein:
the input end of the Boost circuit is used as a pair of direct current ports of the inverter system, and the two poles of the output end of the Boost circuit are correspondingly connected with the two ends of the bus capacitor;
and the controller is connected with the control ends of the switching tubes in the Boost circuit through the corresponding driving circuits.
14. A photovoltaic rapid shutdown system according to any one of claims 11 to 13, wherein the inverter system is a single phase system, or alternatively, a three phase system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110333462.5A CN112821866B (en) | 2021-03-29 | 2021-03-29 | Photovoltaic rapid turn-off system and control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110333462.5A CN112821866B (en) | 2021-03-29 | 2021-03-29 | Photovoltaic rapid turn-off system and control method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112821866A CN112821866A (en) | 2021-05-18 |
| CN112821866B true CN112821866B (en) | 2022-07-12 |
Family
ID=75863600
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110333462.5A Active CN112821866B (en) | 2021-03-29 | 2021-03-29 | Photovoltaic rapid turn-off system and control method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112821866B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103748759A (en) * | 2011-06-27 | 2014-04-23 | 太阳能公司 | Methods and apparatus for controlling operation of photovoltaic power plants |
| KR101458363B1 (en) * | 2013-10-22 | 2014-11-06 | 공주대학교 산학협력단 | Maximum power point tracking method of photovoltaic system for tracking maximum power point under varying irradiance |
| WO2016059620A1 (en) * | 2014-10-17 | 2016-04-21 | Isis Innovation Ltd | Method and apparatus for assessing photoresponsive elements |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2867592C (en) * | 2011-07-11 | 2019-10-29 | Sinewatts, Inc. | Systems and methods for solar photovoltaic energy collection and conversion |
| CN104201720B (en) * | 2014-09-12 | 2016-09-21 | 阳光电源股份有限公司 | The control method of a kind of grid-connected system resonance suppression and device |
| EP3413454A1 (en) * | 2017-06-07 | 2018-12-12 | ABB Schweiz AG | Method for operating inverter and inverter arrangement |
| CN111585308B (en) * | 2020-06-15 | 2022-04-08 | 阳光电源股份有限公司 | Control method of photovoltaic rapid turn-off system and application device and system thereof |
| CN111756072B (en) * | 2020-07-30 | 2022-04-08 | 阳光电源股份有限公司 | Control method and operation control method of MLPE (Multi-layer plasma injection Molding) equipment and photovoltaic system |
-
2021
- 2021-03-29 CN CN202110333462.5A patent/CN112821866B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103748759A (en) * | 2011-06-27 | 2014-04-23 | 太阳能公司 | Methods and apparatus for controlling operation of photovoltaic power plants |
| KR101458363B1 (en) * | 2013-10-22 | 2014-11-06 | 공주대학교 산학협력단 | Maximum power point tracking method of photovoltaic system for tracking maximum power point under varying irradiance |
| WO2016059620A1 (en) * | 2014-10-17 | 2016-04-21 | Isis Innovation Ltd | Method and apparatus for assessing photoresponsive elements |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112821866A (en) | 2021-05-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP3171503B1 (en) | Cascaded multilevel converter self-test system and self-test method for the same | |
| CN106877311B (en) | A kind of direct current photovoltaic generating system | |
| EP3264550B1 (en) | Access control method for parallel direct current power supplies and device thereof | |
| CN112803485B (en) | Photovoltaic rapid turn-off system and control method thereof | |
| CN106992550B (en) | Control device and collection flow box | |
| CN103973146B (en) | The determination methods of a kind of cell panel access module and inverter | |
| EP3996239A1 (en) | Troubleshooting method and apparatus for power supply device | |
| CN109655757B (en) | UPS system detection method and system | |
| CN102280862A (en) | Frequency converter input/output reverse connection detection protection method and device | |
| US11726133B2 (en) | Energy storage system and insulation detection method therefor | |
| CN105021977A (en) | AC relay detection method and system before grid connection of photovoltaic inverter | |
| CN103630832B (en) | A kind of power electronic equipment breaker in middle part startup self-detection method and device | |
| CN104467016A (en) | Pre-charging control method and system for five-level photovoltaic inverter | |
| EP3872958A1 (en) | Photovoltaic electricity utilization device and charging control method, apparatus and circuit therefor, and storage medium | |
| CN112821866B (en) | Photovoltaic rapid turn-off system and control method thereof | |
| JP6385269B2 (en) | Grid-connected inverter device | |
| CN105762834A (en) | Photovoltaic inverter intelligent starting control system | |
| CN107390079B (en) | Current transformer, crowbar circuit, state detection method and control method of crowbar circuit | |
| CN112838618B (en) | Photovoltaic module shutoff device, inverter, photovoltaic rapid shutoff system and starting method of photovoltaic rapid shutoff system | |
| CN215894753U (en) | Insulation impedance detection circuit, equipment and vehicle | |
| CN115047277A (en) | Energy storage system and branch anomaly detection method thereof | |
| KR20150005822A (en) | Apparatus and method of controlling instant power failure of h-bridge multi-level inverter | |
| CN109412157B (en) | AC input phase-failure phase-switching circuit | |
| CN102608470B (en) | Judge the method and system of stability of active power filer | |
| CN220139249U (en) | Photovoltaic power generation control system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |