CN113991612A - Group string type photovoltaic inverter system and electronic equipment - Google Patents
Group string type photovoltaic inverter system and electronic equipment Download PDFInfo
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- CN113991612A CN113991612A CN202111274797.0A CN202111274797A CN113991612A CN 113991612 A CN113991612 A CN 113991612A CN 202111274797 A CN202111274797 A CN 202111274797A CN 113991612 A CN113991612 A CN 113991612A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/122—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters
- H02H7/1222—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters responsive to abnormalities in the input circuit, e.g. transients in the DC input
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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
- H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
- H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
- H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/12—Arrangements for reducing harmonics from ac input or output
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
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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
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B10/00—Integration of renewable energy sources in buildings
- Y02B10/70—Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
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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
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
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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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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
- Y04S20/20—End-user application control systems
Abstract
The application provides a group's string-type photovoltaic inverter system and electronic equipment includes: the output of the n paths of level conversion circuits are connected in parallel and then input into the grid-connected power unit; the circuit structures from the first path of level conversion circuit to the nth path of level conversion circuit are the same, the functions of the circuits are the same, and n is greater than or equal to 1; the specific structure of the first path of level conversion circuit comprises: the lightning arrester comprises a first path of hybrid switch, a first path of lightning arrester combination, a first path of common mode inductor and a first path of level converter; the first path of photovoltaic input signals are total input after the confluence of the plurality of paths of sub-photovoltaic cell panels, the first path of photovoltaic input signals are input into the first path of level conversion circuit, are input into the first path of lightning arrester combination and the first path of common mode inductor after passing through the first path of hybrid switch, and are input into the first path of level converter, and the changed first path of photovoltaic input signals are obtained.
Description
Technical Field
The present application relates to the field of photovoltaic power generation, and in particular, to a string-type photovoltaic inverter system and an electronic device.
Background
With the capacity of the photovoltaic cell panel increasing, the parallel number of the group strings is increased. When a certain PV is short-circuited or reverse-connected, the short-circuit current is also larger and larger. As shown in fig. 6, when the front end of the grid-connected power unit of the PV branch is short-circuited or the power unit fails, a large current is generated on the line, which is very likely to cause damage to cables or components, and even cause fire due to long-term overheating.
A two-stage power converter and system with a lightning protection design is disclosed. The two-stage power converter comprises a plurality of front-stage power conversion units and a rear-stage power conversion unit, wherein the input of each front-stage power conversion unit is independent, the output of each front-stage power conversion unit is connected to the rear-stage power conversion unit in parallel, the front-stage power conversion unit is a three-level Boost circuit with a bypass diode, and in addition: each preceding power conversion unit is provided with a Y-shaped lightning protection circuit which is connected between the input anode and the input cathode of the preceding power conversion unit and the ground and is composed of a lightning protection device.
The method comprises the following steps: the intelligent segmentation capability is not provided, and the front-stage power conversion unit adopts a three-level Boost circuit with a bypass switch, so that the circuit is complex.
The prior art has two schemes, scheme 1: a fuse is added at the PV confluence input end; scheme 2: and a breaker is added at the PV confluence input end. The mechanism of the fuse of scheme 1 is that when the current in the circuit exceeds a specified value for a period of time, the fuse melts the fuse with its own heat, thereby breaking the circuit and protecting the device. However, this scheme has poor real-time performance and needs to be used with an isolating switch in a system. And in the second scheme, the circuit breaker is tripped when the current of the PV is detected in real time and the PV is judged to be in an overcurrent state. Because the circuit breaker is a mechanical switch, the time delay is larger. And the circuit breaker needs to possess the arc extinguishing function, and volume and weight are great, and the cost is higher.
Disclosure of Invention
In view of the above, the present application provides a string-type photovoltaic inverter system and an electronic device.
The application provides a group string photovoltaic inverter system includes:
the output of the n paths of level conversion circuits are connected in parallel and then input into the grid-connected power unit; the circuit structures from the first path of level conversion circuit to the nth path of level conversion circuit are the same, the functions of the circuits are the same, and n is greater than or equal to 1;
the specific structure of the first path of level conversion circuit comprises: the lightning arrester comprises a first path of hybrid switch, a first path of lightning arrester combination, a first path of common mode inductor and a first path of level converter; the first path of photovoltaic input signals are total input after the confluence of a plurality of paths of sub-photovoltaic cell panels, the first path of photovoltaic input signals are input into the first path of level conversion circuit, the first path of photovoltaic input signals pass through the first path of mixing switch and then are input into the first path of lightning arrester combination and the first path of common mode inductor, then the first path of level converter is input into the first path of level converter, the changed first path of photovoltaic input signals are obtained, the changed first path of photovoltaic input signals are connected with other paths of changed photovoltaic input in parallel to form a total direct current bus, and the total direct current bus enters the grid-connected power unit.
In some embodiments, the first hybrid switch is composed of two switch sets, the first switch set is disposed on a positive line of the first photovoltaic input signal, and the second switch set is disposed on a negative line of the first photovoltaic input signal;
the first switch group is formed by connecting two switches in parallel and is respectively a first thyristor device and a first switch device; the second switch group is formed by connecting two switches in parallel, and is respectively a second thyristor device and a second switch device.
In some embodiments, the first switch set further comprises: the first voltage detection device is connected with the first thyristor device and the first switch device in parallel; the second switch group further includes: second voltage detection means are connected in parallel with said second thyristor device and said second switching device.
In some embodiments, the method for applying the first hybrid switch to the string-type photovoltaic inverter includes: switching on and switching off;
the specific method for closing the switch comprises the following steps:
closing step 1: when the input direct current meets a closing condition, the first thyristor device and the second thyristor device are simultaneously switched on;
closing step 2: after the first thyristor device and the second thyristor device are confirmed to be conducted through the first voltage detection device and the second voltage detection device, the first switch device and the second switch device are turned on simultaneously;
and (3) closing: after the first switching device and the second switching device are confirmed to be closed through judging feedback signals of the first switching device and the second switching device, the first thyristor device and the second thyristor device are turned off, and the first switching device and the second switching device are in a conducting state;
the specific method for opening the brake comprises the following steps:
opening the gate step 1: when a system switching-off command is received, the first thyristor device and the second thyristor device are simultaneously switched on;
and (3) switching off step 2: after the first thyristor device and the second thyristor device are confirmed to be conducted through the first voltage detection device and the second voltage detection device, the first switching device and the second switching device are simultaneously separated;
and (3) switching off: and turning off the first thyristor device and the second thyristor device after confirming that the first switching device and the second switching device are separated by judging feedback signals of the first switching device and the second switching device.
In some embodiments, the power supply of the first hybrid switch includes:
an alternating current energy-taking power supply and a direct current energy-taking power supply;
the alternating current energy taking power supply takes power at the alternating current side at the rear end of the grid-connected power unit;
the direct current energy taking power supply takes electricity at the direct current side of the front end of the grid-connected power unit.
In some embodiments, the power supply application method of the first hybrid switch includes:
when the voltage of the direct current side of the group string type inverter is normal or the voltage of the alternating current side of the group string type inverter is failed, the direct current energy-taking power supply of the direct current side is adopted for supplying power;
and when the direct current energy-taking power supply on the direct current side is in voltage loss or fault, the alternating current energy-taking power supply on the alternating current side is adopted.
In some embodiments, each photovoltaic input positive and negative electrode lightning arrester adopts a star connection method; one lightning arrester is used for all the negative poles.
In some embodiments, the first path of level converter is a two-level BOOST converter.
In some embodiments, the specific structure of the two-level BOOST converter includes:
the device comprises a first support capacitor, a boost inductor, a two-level bridge arm and a second support capacitor;
and the direct-current input voltage is input into the first supporting capacitor, passes through the boosting inductor and the two-level bridge arm, is output to the second supporting capacitor and is converted into direct-current output voltage.
The electronic equipment provided by the application comprises the string-type photovoltaic inverter system.
The application provides a group's string-type photovoltaic inverter system and electronic equipment has following beneficial effect: the system can avoid the expansion of faults of the photovoltaic cell panel and the inverter, improve the system safety and reduce the size and the weight.
Drawings
The present application will be described in more detail below on the basis of embodiments and with reference to the accompanying drawings.
Fig. 1 is a schematic diagram of a string-type photovoltaic inverter system according to an embodiment of the present disclosure;
FIG. 2 is a schematic diagram of a hybrid switch provided in an embodiment of the present application;
fig. 3 is a schematic diagram of a hybrid switching power supply according to an embodiment of the present application;
fig. 4 is a schematic view of a lightning arrester assembly provided in an embodiment of the present application;
FIG. 5 is a BOOST circuit diagram provided by an embodiment of the present application;
fig. 6 is a diagram of PV short circuit current provided by the prior art.
In the drawings, like parts are designated with like reference numerals, and the drawings are not drawn to scale.
Detailed Description
In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be described in further detail with reference to the attached drawings, the described embodiments should not be considered as limiting the present application, and all other embodiments obtained by a person of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.
In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is understood that "some embodiments" may be the same subset or different subsets of all possible embodiments, and may be combined with each other without conflict.
The following description will be added if a similar description of "first \ second \ third" appears in the application file, and in the following description, the terms "first \ second \ third" merely distinguish similar objects and do not represent a specific ordering for the objects, and it should be understood that "first \ second \ third" may be interchanged under certain circumstances in a specific order or sequence, so that the embodiments of the application described herein can be implemented in an order other than that shown or described herein.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of the present application only and is not intended to be limiting of the application.
Before introducing a group string type photovoltaic inverter system provided by the embodiments of the present application, a brief description is given of the problems in the related art:
a two-stage power converter and system with a lightning protection design is disclosed. The two-stage power converter comprises a plurality of front-stage power conversion units and a rear-stage power conversion unit, wherein the input of each front-stage power conversion unit is independent, the output of each front-stage power conversion unit is connected to the rear-stage power conversion unit in parallel, the front-stage power conversion unit is a three-level Boost circuit with a bypass diode, and in addition: each preceding power conversion unit is provided with a Y-shaped lightning protection circuit which is connected between the input anode and the input cathode of the preceding power conversion unit and the ground and is composed of a lightning protection device.
The method comprises the following steps: the intelligent segmentation capability is not provided, and the front-stage power conversion unit adopts a three-level Boost circuit with a bypass switch, so that the circuit is complex.
The prior art has two schemes, scheme 1: a fuse is added at the PV confluence input end; scheme 2: and a breaker is added at the PV confluence input end. The mechanism of the fuse of scheme 1 is that when the current in the circuit exceeds a specified value for a period of time, the fuse melts the fuse with its own heat, thereby breaking the circuit and protecting the device. However, this scheme has poor real-time performance and needs to be used with an isolating switch in a system. And in the second scheme, the circuit breaker is tripped when the current of the PV is detected in real time and the PV is judged to be in an overcurrent state. Because the circuit breaker is a mechanical switch, the time delay is larger. And the circuit breaker needs to possess the arc extinguishing function, and volume and weight are great, and the cost is higher.
Based on the problems in the related art, embodiments of the present application provide a string-type photovoltaic inverter system, which is applied to a string-type photovoltaic inverter device, where the string-type photovoltaic inverter device may be an electronic device, such as a computer, a mobile terminal, and the like. The functions implemented by the string-type photovoltaic inverter system provided by the embodiment of the present application may be implemented by a processor of an electronic device calling a program code, where the program code may be stored in a computer storage medium.
Example one
An embodiment of the present application provides a string-type photovoltaic inverter system, and fig. 1 is a diagram of the string-type photovoltaic inverter system provided in the embodiment of the present application, as shown in fig. 1, including:
the output of the n paths of level conversion circuits are connected in parallel and then input into the grid-connected power unit; the circuit structures from the first path of level conversion circuit to the nth path of level conversion circuit are the same, the functions of the circuits are the same, and n is greater than or equal to 1;
the specific structure of the first path of level conversion circuit comprises: the system comprises a first path of hybrid switch Q1, a first path of lightning arrester combination SPD11, a SPD12, a SPD _ N, a first path of common mode inductor T1 and a first path of level converter BOOST 1; the first path of photovoltaic input signals are total input after the multiple paths of sub-photovoltaic cell panels are converged, the first path of photovoltaic input signals are input into the first path of level conversion circuit, the first path of photovoltaic input signals pass through the first path of mixing switch Q1, then are input into the first path of lightning arrester combination SPD11, SPD12, SPD _ N and the first path of common mode inductor T1, then are input into the first path of level converter BOOST1, changed first path of photovoltaic input signals are obtained, the changed first path of photovoltaic input signals are connected with other changed photovoltaic inputs in parallel to form a total direct current bus, and the total direct current bus enters a grid-connected power unit.
In some embodiments, as shown in fig. 2, the first hybrid switch Q1 is composed of two switch sets, a first switch set is disposed on a positive line of the first photovoltaic input signal, and a second switch set is disposed on a negative line of the first photovoltaic input signal;
the first switch group is formed by connecting two switches in parallel, namely a first thyristor device S11 and a first switch device K11; the second switch group is formed by connecting two switches in parallel, namely a second thyristor device S12 and a second switch device K12.
In some embodiments, the first switch set further comprises: a first voltage detection device V11 is connected in parallel with the first thyristor device S11 and the first switching device K11; the second switch group further includes: a second voltage detection means V12 is connected in parallel with the second thyristor device S12 and the second switching device K12.
In some embodiments, the method for applying the first hybrid switch Q1 to the string-type photovoltaic inverter includes: switching on and switching off;
the specific method for closing the switch comprises the following steps:
closing step 1: when the input direct current meets a closing condition, simultaneously turning on the first thyristor device S11 and the second thyristor device S12;
closing step 2: after the first voltage detection device V11 and the second voltage detection device V12 confirm that the first thyristor device S11 and the second thyristor device S12 are turned on, the first switching device K11 and the second switching device K12 are turned on at the same time;
and (3) closing: after confirming that the first switching device K11 and the second switching device K12 are turned on by judging feedback signals of the first switching device K11 and the second switching device K12, turning off the first thyristor device S11 and the second thyristor device S12, wherein the first switching device K11 and the second switching device K12 are in a conducting state;
the specific method for opening the brake comprises the following steps:
opening the gate step 1: when a system switching-off command is received, the first thyristor device S11 and the second thyristor device S12 are turned on simultaneously;
and (3) switching off step 2: after the first voltage detection device V11 and the second voltage detection device V12 confirm that the first thyristor device S11 and the second thyristor device S12 are turned on, the first switching device K11 and the second switching device K12 are simultaneously separated;
and (3) switching off: after the first switching device K11 and the second switching device K12 are confirmed to be separated by judging feedback signals of the first switching device K11 and the second switching device K12, the first thyristor device S11 and the second thyristor device S12 are turned off.
In some embodiments, as shown in fig. 3, the power supply of the first hybrid switch Q1 includes:
an alternating current energy-taking power supply and a direct current energy-taking power supply;
the alternating current energy taking power supply takes power at the alternating current side at the rear end of the grid-connected power unit;
the direct current energy taking power supply takes electricity at the direct current side of the front end of the grid-connected power unit.
In some embodiments, the method for applying the power supply of the first hybrid switch Q1 includes:
when the voltage of the direct current side of the group string type inverter is normal or the voltage of the alternating current side of the group string type inverter is failed, the direct current energy-taking power supply of the direct current side is adopted for supplying power;
and when the direct current energy-taking power supply on the direct current side is in voltage loss or fault, the alternating current energy-taking power supply on the alternating current side is adopted.
In some embodiments, as shown in fig. 4, each photovoltaic input positive and negative lightning arrester adopts a star connection method; since the negative poles of all the photovoltaic inputs are all connected together, the negative pole uses one lightning arrester.
In some embodiments, the first branch level converter BOOST1 is a two-level BOOST converter.
In some embodiments, as shown in fig. 5, the specific structure of the two-level BOOST converter includes:
the circuit comprises a first support capacitor C11, a boost inductor L11, a two-level bridge arm S13, D11, D12 and a second support capacitor C12;
a dc input voltage U1 is input to the first supporting capacitor C11, passes through the boosting inductor L11, passes through the two-level bridge arms S13, D11, and D12, and is output to the second supporting capacitor C12, and is converted into a dc output voltage U2.
The application provides a group string type photovoltaic inverter system,
(1) when the PV direct current input of the string type photovoltaic inverter fails, the inverter is disconnected and isolated in real time, so that the fault expansion of the photovoltaic cell panel and the inverter is avoided, and the system safety is improved;
(2) an electronic switch is adopted to replace a purely mechanical switch, so that the switching speed and the breaking capacity are provided;
(3) the composite switch is adopted to replace a pure mechanical switch, the mechanical part does not need to be separated and combined with a load, an arc extinguishing device is not needed, and the size and the weight are reduced.
Example two
Based on the foregoing embodiments, an embodiment of the present application provides an electronic device, including: the string-type photovoltaic inverter system of embodiment 1 is included.
It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that, in the various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application. The above-mentioned serial numbers of the embodiments of the present application are merely for description and do not represent the merits of the embodiments.
It should be noted that, in this document, 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 like elements in a process, method, article, or apparatus that comprises the element.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above-described device embodiments are merely illustrative, for example, the division of the unit is only a logical functional division, and there may be other division ways in actual implementation, such as: multiple units or components may be combined, or may be integrated into another system, or some features may be omitted, or not implemented. In addition, the coupling, direct coupling or communication connection between the components shown or discussed may be through some interfaces, and the indirect coupling or communication connection between the devices or units may be electrical, mechanical or other forms.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units; can be located in one place or distributed on a plurality of network units; some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, all functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may be separately regarded as one unit, or two or more units may be integrated into one unit; the integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.
The above description is only for the embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (10)
1. A string photovoltaic inverter system, comprising:
the output of the n paths of level conversion circuits are connected in parallel and then input into the grid-connected power unit; the circuit structures from the first path of level conversion circuit to the nth path of level conversion circuit are the same, the functions of the circuits are the same, and n is greater than or equal to 1;
the specific structure of the first path of level conversion circuit comprises: the lightning arrester comprises a first path of hybrid switch, a first path of lightning arrester combination, a first path of common mode inductor and a first path of level converter; the first path of photovoltaic input signals are total input after the confluence of a plurality of paths of sub-photovoltaic cell panels, the first path of photovoltaic input signals are input into the first path of level conversion circuit, the first path of photovoltaic input signals pass through the first path of mixing switch and then are input into the first path of lightning arrester combination and the first path of common mode inductor, then the first path of level converter is input into the first path of level converter, the changed first path of photovoltaic input signals are obtained, the changed first path of photovoltaic input signals are connected with other paths of changed photovoltaic input in parallel to form a total direct current bus, and the total direct current bus enters the grid-connected power unit.
2. The system according to claim 1, wherein the first hybrid switch is composed of two switch sets, the first switch set is disposed on a positive line of the first photovoltaic input signal, and the second switch set is disposed on a negative line of the first photovoltaic input signal;
the first switch group is formed by connecting two switches in parallel and is respectively a first thyristor device and a first switch device; the second switch group is formed by connecting two switches in parallel, and is respectively a second thyristor device and a second switch device.
3. The system of claim 2, wherein the first switch set further comprises: the first voltage detection device is connected with the first thyristor device and the first switch device in parallel; the second switch group further includes: second voltage detection means are connected in parallel with said second thyristor device and said second switching device.
4. The system of claim 3, wherein the method for applying the first hybrid switch to the string-type photovoltaic inverter comprises: switching on and switching off;
the specific method for closing the switch comprises the following steps:
closing step 1: when the input direct current meets a closing condition, the first thyristor device and the second thyristor device are simultaneously switched on;
closing step 2: after the first thyristor device and the second thyristor device are confirmed to be conducted through the first voltage detection device and the second voltage detection device, the first switch device and the second switch device are turned on simultaneously;
and (3) closing: after the first switching device and the second switching device are confirmed to be closed through judging feedback signals of the first switching device and the second switching device, the first thyristor device and the second thyristor device are turned off, and the first switching device and the second switching device are in a conducting state;
the specific method for opening the brake comprises the following steps:
opening the gate step 1: when a system switching-off command is received, the first thyristor device and the second thyristor device are simultaneously switched on;
and (3) switching off step 2: after the first thyristor device and the second thyristor device are confirmed to be conducted through the first voltage detection device and the second voltage detection device, the first switching device and the second switching device are simultaneously separated;
and (3) switching off: and turning off the first thyristor device and the second thyristor device after confirming that the first switching device and the second switching device are separated by judging feedback signals of the first switching device and the second switching device.
5. The system of claim 4, wherein the power supply component of the first hybrid switch comprises:
an alternating current energy-taking power supply and a direct current energy-taking power supply;
the alternating current energy taking power supply takes power at the alternating current side at the rear end of the grid-connected power unit;
the direct current energy taking power supply takes electricity at the direct current side of the front end of the grid-connected power unit.
6. The system of claim 5, wherein the power supply applying method of the first hybrid switch comprises:
when the voltage of the direct current side of the group string type inverter is normal or the voltage of the alternating current side of the group string type inverter is failed, the direct current energy-taking power supply of the direct current side is adopted for supplying power;
and when the direct current energy-taking power supply on the direct current side is in voltage loss or fault, the alternating current energy-taking power supply on the alternating current side is adopted.
7. The system of claim 1, wherein each photovoltaic input positive and negative lightning arrester is connected in star; one lightning arrester is used for all the negative poles.
8. The system of claim 1, wherein the first channel level converter is a two-level BOOST converter.
9. The system of claim 8, wherein the two-level BOOST converter comprises:
the device comprises a first support capacitor, a boost inductor, a two-level bridge arm and a second support capacitor;
and the direct-current input voltage is input into the first supporting capacitor, passes through the boosting inductor and the two-level bridge arm, is output to the second supporting capacitor and is converted into direct-current output voltage.
10. An electronic device comprising the string-type photovoltaic inverter system according to any one of claims 1 to 9.
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