CN113131509B - Photovoltaic inverter - Google Patents
Photovoltaic inverter Download PDFInfo
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- CN113131509B CN113131509B CN202010039933.7A CN202010039933A CN113131509B CN 113131509 B CN113131509 B CN 113131509B CN 202010039933 A CN202010039933 A CN 202010039933A CN 113131509 B CN113131509 B CN 113131509B
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- 238000006243 chemical reaction Methods 0.000 claims abstract description 53
- 238000010586 diagram Methods 0.000 description 14
- 238000000034 method Methods 0.000 description 6
- 238000010248 power generation Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
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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
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/28—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for meshed systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
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- 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
- H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
- H02S40/30—Electrical components
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- 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
- H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
- H02S40/30—Electrical components
- H02S40/36—Electrical components characterised by special electrical interconnection means between two or more PV modules, e.g. electrical module-to-module connection
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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
Abstract
The invention discloses a photovoltaic inverter, which comprises an auxiliary power supply, a series switch module, a direct current-direct current conversion circuit and a direct current-alternating current inverter circuit, wherein the auxiliary power supply is connected with the series switch module; the input end of the auxiliary power supply is connected with the output end of the photovoltaic module, and the auxiliary power supply is used for supplying power to the series switch module, the direct current-direct current conversion circuit and the direct current-alternating current inverter circuit; the series switch module is arranged on a series path among the photovoltaic modules; the input end of the direct current-direct current conversion circuit is connected with the output end of each photovoltaic module after being connected in series, and then the direct current-direct current conversion circuit is connected to a power grid through the direct current-alternating current inverter circuit. The photovoltaic grid-connected system can realize that a plurality of photovoltaic components are connected in series to form a string, then the direct current is converted into alternating current to be connected to the grid, and the component-level switching-off of each photovoltaic component can be realized without additionally arranging a component-level switching-off device, so that the system complexity is reduced on the premise of ensuring the switching-off safety of the components of the photovoltaic grid-connected system, and the cost of the photovoltaic grid-connected system is further reduced.
Description
Technical Field
The invention relates to the technical field of photovoltaic grid-connected power generation, in particular to a photovoltaic inverter.
Background
Due to the reproducibility and cleanness of solar energy, the photovoltaic grid-connected power generation technology is rapidly developed to simplify the design of an inverter, the cost is reduced, a plurality of photovoltaic modules of a photovoltaic system are connected in series to form a string and then connected into the photovoltaic inverter to realize the direct current conversion into the alternating current for grid connection, and a plurality of direct current-direct current conversion circuits, inverter circuits and other parts required in the system are reduced into one.
Fig. 1 is a schematic structural diagram of a photovoltaic inverter in the prior art.
As shown in fig. 1, a dashed line frame is a photovoltaic inverter in the prior art, and the photovoltaic inverter is provided with a positive input end PV + and a negative input end PV-, and an auxiliary power supply, a dc-dc conversion circuit and a dc-ac inverter circuit are arranged inside the PV inverter, the PV 1-end of the photovoltaic module 1 is connected in series with the PV2+ end of the photovoltaic module 2, the PV1+ end of the photovoltaic module 1 is connected with the positive input end PV + of the photovoltaic inverter, and the PV 2-end of the photovoltaic module 2 is connected with the negative input end PV-of the photovoltaic inverter, so that the photovoltaic module 1 and the photovoltaic module 2 are connected in series to form a string and then connected to the photovoltaic inverter to realize dc conversion into ac and grid connection, and a plurality of parts such as the dc-dc conversion circuit and the dc-ac inverter circuit required in the system are reduced to one.
However, the series-connected photovoltaic modules form a direct-current high voltage, which may cause personal risks and fire accidents, so that when the photovoltaic grid-connected power generation system is installed and connected, additional shutdown devices at the level of connection components are required between the output paths of the photovoltaic modules and the photovoltaic inverters, which increases the wiring difficulty and the required cost.
Disclosure of Invention
The invention aims to provide a photovoltaic inverter which is used for reducing the complexity of a system on the premise of ensuring the safety of the turn-off of a photovoltaic grid-connected system component so as to reduce the cost of the photovoltaic grid-connected system.
In order to solve the above technical problems, the present invention provides a photovoltaic inverter, which includes an auxiliary power supply, a series switch module, a dc-dc conversion circuit and a dc-ac inverter circuit;
the input end of the auxiliary power supply is connected with the output end of the photovoltaic module, and the auxiliary power supply is used for supplying power to the series switch module, the direct current-direct current conversion circuit and the direct current-alternating current inverter circuit; the series switch module is arranged on a series path among the photovoltaic modules; the input end of the direct current-direct current conversion circuit is connected with the output end of each photovoltaic module after being connected in series; the input end of the direct current-alternating current inverter circuit is connected with the output end of the direct current-direct current conversion circuit, and the output end of the direct current-alternating current inverter circuit is connected to a power grid.
Optionally, the series switch module specifically includes a switch device disposed in the series path and a switch driving circuit connected to a control end of the switch device.
Optionally, the switching device is specifically an MOS transistor, an IGBT, a thyristor, a triode, or a relay.
Optionally, the driving circuit specifically includes an optocoupler or a transformer or a driving chip.
Optionally, the series switch module further includes a switch control circuit connected to the input terminal of the switch driving circuit and configured to control the switch driving circuit to control the on/off of the switch device.
Optionally, a positive input end of the auxiliary power supply is connected with a first positive input end of the photovoltaic inverter, and a negative input end of the auxiliary power supply is connected with a first negative input end of the photovoltaic inverter; the positive output end of the auxiliary power supply is connected with the positive input end of the direct current-direct current conversion circuit, and the first negative input end of the photovoltaic inverter is connected with the negative input end of the direct current-direct current conversion circuit through a jumper wire.
Optionally, a positive input end of the auxiliary power supply is connected to a first positive input end of the photovoltaic inverter, and a negative input end of the auxiliary power supply is connected to a second negative input end of the photovoltaic inverter through a jumper; and the positive output end of the auxiliary power supply is connected with the positive input end of the direct current-direct current conversion circuit, and the negative output end of the auxiliary power supply is connected with the negative input end of the direct current-direct current conversion circuit.
Optionally, a first input end of the auxiliary power supply is connected to a first positive input end of the photovoltaic inverter, a second input end of the auxiliary power supply is connected to a second positive input end of the photovoltaic inverter, and an output end of the auxiliary power supply is connected to a second negative input end of the photovoltaic inverter; the first end of the series switch module is connected with the first negative electrode input end of the photovoltaic inverter, and the second end of the series switch module is connected with the second positive electrode input end of the photovoltaic inverter.
Optionally, the photovoltaic inverter further includes a first diode disposed between the first input end of the auxiliary power source and the first positive input end of the photovoltaic inverter, and a second diode disposed between the second input end of the auxiliary power source and the second positive input end of the photovoltaic inverter;
the anode end of the first diode is connected with the first anode input end of the photovoltaic inverter, and the cathode end of the first diode is connected with the first input end of the auxiliary power supply; and the anode end of the second diode is connected with the second anode input end of the photovoltaic inverter, and the cathode end of the second diode is connected with the second input end of the auxiliary power supply.
The photovoltaic inverter provided by the invention comprises an auxiliary power supply, a series switch module, a direct current-direct current conversion circuit and a direct current-alternating current inverter circuit; the input end of the auxiliary power supply is connected with the output end of the photovoltaic module, and the auxiliary power supply is used for supplying power to the series switch module, the direct current-direct current conversion circuit and the direct current-alternating current inverter circuit; the series switch module is arranged on a series path of each photovoltaic module; the input end of the direct current-direct current conversion circuit is connected with the output end of each photovoltaic module after being connected in series; the input end of the DC-AC inverter circuit is connected with the output end of the DC-DC conversion circuit, and the output end of the DC-AC inverter circuit is connected with a power grid. According to the photovoltaic inverter provided by the invention, the series switch modules arranged on the series passages of the photovoltaic modules are arranged, so that direct current can be converted into alternating current for grid connection after a plurality of photovoltaic modules are connected in series to form a string, and the assembly-level turn-off of each photovoltaic module can be realized without additionally arranging an assembly-level turn-off device outside the photovoltaic inverter, the system complexity is reduced on the premise of ensuring the turn-off safety of the photovoltaic grid-connected system assembly, and the cost of the photovoltaic grid-connected system is further reduced.
Drawings
In order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a photovoltaic inverter in the prior art;
fig. 2 is a schematic structural diagram of a first photovoltaic inverter according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a second photovoltaic inverter according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a third photovoltaic inverter according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a fourth photovoltaic inverter according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a fifth photovoltaic inverter according to an embodiment of the present invention;
fig. 7 is a schematic connection diagram of the pv inverter-compatible pv modules shown in fig. 6 connected in series outside the pv inverter.
Detailed Description
The core of the invention is to provide a photovoltaic inverter, which is used for reducing the complexity of a system on the premise of ensuring the safety of the turn-off of components of a photovoltaic grid-connected system, thereby reducing the cost of the photovoltaic grid-connected system.
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.
Example one
Fig. 2 is a schematic structural diagram of a first photovoltaic inverter according to an embodiment of the present invention; fig. 3 is a schematic structural diagram of a second photovoltaic inverter according to an embodiment of the present invention.
The photovoltaic inverter provided by the embodiment of the invention comprises an auxiliary power supply, a series switch module, a direct current-direct current conversion circuit and a direct current-alternating current inverter circuit;
the input end of the auxiliary power supply is connected with the output end of the photovoltaic module, and the auxiliary power supply is used for supplying power to the series switch module, the direct current-direct current conversion circuit and the direct current-alternating current inverter circuit; the series switch module is arranged on a series path among the photovoltaic modules; the input end of the direct current-direct current conversion circuit is connected with the output end of each photovoltaic module after being connected in series; the input end of the DC-AC inverter circuit is connected with the output end of the DC-DC conversion circuit, and the output end of the DC-AC inverter circuit is connected with a power grid.
In specific implementation, as shown in fig. 2, taking connection of two photovoltaic modules (photovoltaic module 1 and photovoltaic module 2) as an example, the photovoltaic inverter provided in the embodiment of the present invention realizes that the series switch module controls on/off of connection between the photovoltaic module 1 and the photovoltaic module 2 after the photovoltaic module 1 and the photovoltaic module 2 are connected in series inside the photovoltaic inverter. Accordingly, the photovoltaic inverter has four input terminals: the photovoltaic module comprises a first positive input end PV1+, a first negative input end PV1-, a second positive input end PV2+ and a second negative input end PV2-, wherein the first positive input end PV1+ is used for connecting the positive end of the photovoltaic module 1, the first negative end is used for connecting the negative end of the photovoltaic module 1, the second positive input end PV2+ is used for connecting the positive end of the photovoltaic module 2, and the second negative input end PV 2-is used for connecting the negative end of the photovoltaic module 2.
The input end of the auxiliary power supply can be connected with the output end of the photovoltaic module 1 through a first positive input end PV1+, a first negative input end PV1-, or can be connected with the output end of the photovoltaic module 2 through a second positive input end PV2+, a second negative input end PV 2-.
The first end of the series switch module is connected with the first negative end, the second end of the series switch module is connected with the second positive end, and after the photovoltaic module 1 and the photovoltaic module 2 are connected, the series switch module is arranged on a series connection circuit of the photovoltaic module 1 and the photovoltaic module 2.
The input end of the dc-dc conversion circuit is connected to the output end of the photovoltaic module 1 and the photovoltaic module 2 after being connected in series, when the input end of the auxiliary power supply shown in fig. 2 is connected to the output end of the photovoltaic module 1, the first input end of the dc-dc conversion circuit is connected to the first output end of the auxiliary power supply, and the second input end of the dc-dc conversion circuit is connected to the second negative electrode end.
The input end of the direct current-alternating current inverter circuit is connected with the output end of the direct current-direct current conversion circuit, and the output end of the direct current-alternating current inverter circuit is connected with a power grid, namely a live line L and a zero line N of the alternating current power grid.
The series switch module may specifically include a switch device provided in a series path of the photovoltaic module 1 and the photovoltaic module 2, and a switch driving circuit connected to a control terminal of the switch device. The switching device may specifically adopt an MOS transistor, or may adopt devices having the same function, such as an IGBT, a thyristor, a triode, or a relay. The driving circuit may specifically be implemented by an optocoupler, a transformer, or a driving chip, or other devices.
Further, the series switch module may further include a switch control circuit connected to the input terminal of the switch driving circuit for controlling the switch driving circuit to control the switching device to be turned on or off. That is, the switching control circuit may be disposed outside the photovoltaic inverter provided in the embodiment of the present invention, and integrated with other control circuits, or disposed inside the photovoltaic inverter provided in the embodiment of the present invention, and integrated with the switching device and the driving circuit. The control logic of the switch control circuit may be: detecting an alternating current power grid, and turning on a switching device when the alternating current power grid is normal; and when the alternating current power grid is abnormal, the switching device is turned off.
The scheme that one photovoltaic inverter is connected with more than two photovoltaic modules is similar to the scheme that one photovoltaic inverter is connected with two photovoltaic modules, when the number of input connectors of the photovoltaic inverter is twice of the number of the photovoltaic modules, the series switch module is arranged on a series passage between two adjacent photovoltaic modules. As shown in fig. 3, when one PV inverter is connected to three PV modules, the PV inverter includes six input terminals, namely a first positive input terminal PV1+, a first negative input terminal PV1-, a second positive input terminal PV2+, a second negative input terminal PV2-, a third positive input terminal PV3+ and a third negative input terminal PV3-, and the series switch module includes a first series switch module disposed between the PV module 1 and the PV module 2 and a second series switch module disposed between the PV module 2 and the PV module 3.
The photovoltaic inverter provided by the embodiment of the invention comprises an auxiliary power supply, a series switch module, a direct current-direct current conversion circuit and a direct current-alternating current inverter circuit; the input end of the auxiliary power supply is connected with the output end of the photovoltaic module, and the auxiliary power supply is used for supplying power to the series switch module, the direct current-direct current conversion circuit and the direct current-alternating current inverter circuit; the series switch module is arranged on a series path of each photovoltaic module; the input end of the direct current-direct current conversion circuit is connected with the output end of each photovoltaic module after being connected in series; the input end of the direct current-alternating current inverter circuit is connected with the output end of the direct current-direct current conversion circuit, and the output end of the direct current-alternating current inverter circuit is connected to a power grid. According to the photovoltaic inverter provided by the embodiment of the invention, the series switch module arranged on the series path of each photovoltaic module is arranged, so that a plurality of photovoltaic modules can be connected in series to form a string, then direct current is converted into alternating current to be connected to the grid, and the assembly-level turn-off of each photovoltaic module can be realized without additionally arranging an assembly-level turn-off device outside the photovoltaic inverter, the complexity of the system is reduced on the premise of ensuring the turn-off safety of the photovoltaic grid-connected system assembly, and the cost of the photovoltaic grid-connected system is further reduced.
Example two
Fig. 4 is a schematic structural diagram of a third photovoltaic inverter according to an embodiment of the present invention.
The photovoltaic inverter provided by the first embodiment realizes series connection and module-level shutdown of a plurality of photovoltaic modules in the photovoltaic inverter, and on this basis, since some photovoltaic modules are already connected in series outside the photovoltaic inverter, in order to be compatible with the situation that the photovoltaic modules are connected in series outside the photovoltaic inverter, in the photovoltaic inverter provided by the first embodiment of the present invention, for example, one photovoltaic inverter is used to connect two photovoltaic modules, as shown in fig. 4, the positive input end of the auxiliary power supply is connected with the first positive input end PV1+ of the photovoltaic inverter, and the negative input end of the auxiliary power supply is connected with the first negative input end PV 1-of the photovoltaic inverter; the positive output end of the auxiliary power supply is connected with the positive input end of the direct current-direct current conversion circuit, and the first negative input end PV 1-of the photovoltaic inverter is connected with the negative input end of the direct current-direct current conversion circuit through a jumper wire.
In practical applications, for the case that the photovoltaic modules are connected in series outside the photovoltaic inverter, the photovoltaic inverter provided by the embodiment of the present invention is provided with two input connectors PV + and PV-, wherein PV + corresponds to the first positive input terminal PV1+ in fig. 2, and PV-corresponds to the first negative input terminal PV 1-in fig. 2. The PV1+ end of the photovoltaic module 1 is connected with the PV + end of the photovoltaic inverter, the PV 2-end of the photovoltaic module 2 is connected with the PV-end of the photovoltaic inverter, and the PV 1-end of the photovoltaic module 1 is connected with the PV2+ end of the photovoltaic module 2 in series outside the photovoltaic inverter. At the moment, the series switch module is not connected into the photovoltaic module and the circuit of the photovoltaic inverter, the positive output end of the auxiliary power supply is connected with the positive input end of the direct current-direct current conversion circuit, and the first negative input end PV 1-of the photovoltaic inverter is connected with the negative input end of the direct current-direct current conversion circuit through a jumper wire, so that the compatibility of the situation that the photovoltaic module is connected outside the photovoltaic inverter in series is realized.
It is understood that PV + corresponds to the second positive input PV2+ in fig. 2, PV-corresponds to the second negative input PV2+ in fig. 2, the positive input of the auxiliary power source is connected to the second positive input PV2+ of the photovoltaic inverter, and the negative input of the auxiliary power source is connected to the second negative input PV2+ of the photovoltaic inverter; the negative output end of the auxiliary power supply is connected with the negative input end of the direct current-direct current conversion circuit, and the second negative input end PV 2-of the photovoltaic inverter is connected with the positive input end of the direct current-direct current conversion circuit through a jumper wire, so that the implementation principle is similar to that of the embodiment.
The specific implementation of the photovoltaic inverter provided by the embodiment of the present invention to realize the series connection of the photovoltaic module in the photovoltaic inverter and the shutdown of the module can refer to the description of the first embodiment.
EXAMPLE III
Fig. 5 is a schematic structural diagram of a fourth photovoltaic inverter according to an embodiment of the present invention.
The second embodiment provides a photovoltaic inverter which can realize series connection and component-level shutdown of two photovoltaic components in the photovoltaic inverter and can be compatible with the situation that the photovoltaic components are connected in series outside the photovoltaic inverter.
In the photovoltaic inverter provided by the embodiment of the present invention, for example, one photovoltaic inverter is connected to two photovoltaic modules, as shown in fig. 5, a positive input end of the auxiliary power source is connected to a first positive input end PV1+ of the photovoltaic inverter, and a negative input end of the auxiliary power source is connected to a second negative input end PV 2-of the photovoltaic inverter through a jumper; the positive output end of the auxiliary power supply is connected with the positive input end of the direct current-direct current conversion circuit, and the negative output end of the auxiliary power supply is connected with the negative input end of the direct current-direct current conversion circuit.
In practical application, for the case that the photovoltaic modules are connected in series outside the photovoltaic inverter, the photovoltaic inverter provided by the embodiment of the present invention has two input connectors PV + and PV — which may also correspond to the first positive input terminal PV1+ and the second negative input terminal PV2 — in fig. 2, respectively. The PV1+ end of the photovoltaic module 1 is connected with the PV + end of the photovoltaic inverter, the PV 2-end of the photovoltaic module 2 is connected with the PV-end of the photovoltaic inverter, and the PV 1-end of the photovoltaic module 1 is connected with the PV2+ end of the photovoltaic module 2 in series outside the photovoltaic inverter. At the moment, the series switch module is not connected into the circuit of the photovoltaic module and the photovoltaic inverter, the positive input end of the auxiliary power supply is connected with the first positive input end PV1+ of the photovoltaic inverter, and the negative input end of the auxiliary power supply is connected with the second negative input end PV 2-of the photovoltaic inverter through a jumper; the positive output end of the auxiliary power supply is connected with the positive input end of the direct current-direct current conversion circuit, the negative output end of the auxiliary power supply is connected with the negative input end of the direct current-direct current conversion circuit, and therefore compatibility of the photovoltaic modules outside the photovoltaic inverter in series connection is achieved.
The first embodiment of the present invention can be referred to as the first embodiment, and the specific implementation that the photovoltaic inverter is applied to realize the series connection of the photovoltaic modules in the photovoltaic inverter and the shutdown of the modules in the photovoltaic inverter can be referred to as the second embodiment.
Example four
Fig. 6 is a schematic structural diagram of a fifth photovoltaic inverter according to an embodiment of the present invention; fig. 7 is a schematic connection diagram of the pv inverter-compatible pv modules shown in fig. 6 connected in series outside the pv inverter.
On the basis of the above embodiments, the embodiments of the present invention further provide a photovoltaic inverter compatible with the case where the photovoltaic modules are connected in series outside the photovoltaic inverter.
Taking a PV inverter to connect two PV modules as an example, as shown in fig. 6, in the PV inverter provided in the embodiment of the present invention, a first input terminal of an auxiliary power source is connected to a first positive input terminal PV1+ of the PV inverter, a second input terminal of the auxiliary power source is connected to a second positive input terminal PV2+ of the PV inverter, and an output terminal of the auxiliary power source is connected to a second negative input terminal PV2 ″; the first end of the series switch module is connected with a first negative input PV 1-of the photovoltaic inverter and the second end of the series switch module is connected with a second positive input PV2+ of the photovoltaic inverter.
In practical applications, the photovoltaic inverter provided by the embodiment of the present invention still includes four connectors, i.e., the first positive input PV1+, the first negative input PV1-, the second positive input PV2+, and the second negative input PV2-, on the basis of which the first input of the auxiliary power source is connected to the first positive input PV1+ of the photovoltaic inverter, the second input of the auxiliary power source is connected to the second positive input PV2+ of the photovoltaic inverter, and the output of the auxiliary power source is connected to the second negative input PV2-, i.e., the photovoltaic module 1 and the photovoltaic module 2 simultaneously supply power to the auxiliary power source, and the auxiliary power source is grounded at the second negative input PV 2-. Meanwhile, the series switch is connected into the series path of the photovoltaic module 1 and the photovoltaic module 2 through a first negative electrode input PV 1-and a second positive electrode input PV2 +. The connection of the auxiliary power supply to the dc-dc conversion circuit and the dc-ac inverter circuit is as described in the above embodiments.
Further, to prevent the current from flowing backward, the photovoltaic inverter provided by the embodiment of the present invention further includes a first diode D1 disposed between the first input terminal of the auxiliary power source and the first positive input terminal PV1+ of the photovoltaic inverter, and a second diode D2 disposed between the second input terminal of the auxiliary power source and the second positive input terminal PV2+ of the photovoltaic inverter;
an anode end of the first diode D1 is connected with a first positive electrode input end PV1+ of the photovoltaic inverter, and a cathode end of the first diode D1 is connected with a first input end of the auxiliary power supply; an anode terminal of the second diode D2 is connected to the second positive input terminal PV2+ of the photovoltaic inverter, and a cathode terminal of the second diode D2 is connected to the second input terminal of the auxiliary power supply.
The photovoltaic inverter provided by the embodiment of the invention is used for realizing the connection mode of series connection and disconnection of the photovoltaic modules in the photovoltaic inverter, and the connection mode can be shown in fig. 6.
As shown in fig. 7, when the photovoltaic module is connected in series outside the photovoltaic inverter by using the photovoltaic inverter provided in the embodiment of the present invention, it is only necessary to connect the PV1+ terminal of the photovoltaic module 1 to the first positive terminal of the photovoltaic inverter and connect the PV 2-terminal of the photovoltaic module 2 to the second negative input terminal PV 2-of the photovoltaic inverter, and at this time, the series switch module is not connected to the circuits of the photovoltaic module and the photovoltaic inverter.
The photovoltaic inverter provided by the invention is described in detail above. The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, it is possible to make various improvements and modifications to the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Claims (6)
1. A photovoltaic inverter is characterized by comprising an auxiliary power supply, a series switch module, a direct current-direct current conversion circuit and a direct current-alternating current inverter circuit;
the input end of the auxiliary power supply is connected with the input end of the photovoltaic inverter, and the auxiliary power supply is used for supplying power to the series switch module, the direct current-direct current conversion circuit and the direct current-alternating current inverter circuit; the series switch module is arranged in a series passage for series connection in the photovoltaic inverter among the photovoltaic modules; the input end of the direct current-direct current conversion circuit is connected with the output end of each photovoltaic module after being connected in series; the input end of the direct current-alternating current inverter circuit is connected with the output end of the direct current-direct current conversion circuit, and the output end of the direct current-alternating current inverter circuit is connected to a power grid;
when the photovoltaic modules are not connected in series outside the photovoltaic inverter, the input end of the auxiliary power supply is connected with the output end of any one of the photovoltaic modules;
when the photovoltaic modules are connected in series outside the photovoltaic inverter, the positive input end of the auxiliary power supply is connected with the first positive input end of the photovoltaic inverter, and the negative input end of the auxiliary power supply is connected with the first negative input end of the photovoltaic inverter; the positive electrode output end of the auxiliary power supply is connected with the positive electrode input end of the direct current-direct current conversion circuit, the negative electrode output end of the auxiliary power supply is connected with the negative electrode input end of the direct current-direct current conversion circuit, and the first negative electrode input end of the photovoltaic inverter is connected with the negative electrode input end of the direct current-direct current conversion circuit through a jumper wire; the positive electrode of the string formed by each photovoltaic component is connected with the first positive electrode input end of the photovoltaic inverter, and the negative electrode of the string formed by each photovoltaic component is connected with the first negative electrode input end of the photovoltaic inverter;
or the like, or a combination thereof,
when the photovoltaic modules are connected in series outside the photovoltaic inverter, the positive input end of the auxiliary power supply is connected with the first positive input end of the photovoltaic inverter, and the negative input end of the auxiliary power supply is connected with the second negative input end of the photovoltaic inverter through a jumper wire; the positive output end of the auxiliary power supply is connected with the positive input end of the direct current-direct current conversion circuit, and the negative output end of the auxiliary power supply is connected with the negative input end of the direct current-direct current conversion circuit; the positive electrode of the string formed by each photovoltaic component is connected with the first positive electrode input end of the photovoltaic inverter, and the negative electrode of the string formed by each photovoltaic component is connected with the second negative electrode input end of the photovoltaic inverter;
or the like, or, alternatively,
when the photovoltaic modules are connected in series outside the photovoltaic inverter, a first input end of the auxiliary power supply is connected with a first positive input end of the photovoltaic inverter, a second input end of the auxiliary power supply is connected with a second positive input end of the photovoltaic inverter, and an output end of the auxiliary power supply is connected with a second negative input end of the photovoltaic inverter; a first end of the series switch module is connected with a first negative input end of the photovoltaic inverter, and a second end of the series switch module is connected with a second positive input end of the photovoltaic inverter; the positive electrode of the string formed by each photovoltaic component is connected with the first positive electrode input end of the photovoltaic inverter, and the negative electrode of the string formed by each photovoltaic component is connected with the second negative electrode input end of the photovoltaic inverter;
the first positive electrode input end of the photovoltaic inverter and the first negative electrode input end of the photovoltaic inverter are input ends used for connecting the first photovoltaic module when the photovoltaic modules are not connected in series outside the photovoltaic inverter; the second positive input end of the photovoltaic inverter and the second negative input end of the photovoltaic inverter are input ends for connecting the last photovoltaic module when each photovoltaic module is not connected in series outside the photovoltaic inverter.
2. The pv inverter of claim 1, wherein the series switching module comprises a switching device disposed in the series path and a switch driving circuit connected to a control terminal of the switching device.
3. Photovoltaic inverter according to claim 2, characterized in that the switching device is in particular a MOS transistor or an IGBT or a thyristor or a triode or a relay.
4. The pv inverter of claim 2, wherein the driver circuit is a optocoupler or a transformer or a driver chip.
5. The pv inverter of claim 2 wherein the series switching module further comprises a switch control circuit connected to an input of the switch driver circuit for controlling the switch driver circuit to turn the switching devices on and off.
6. The photovoltaic inverter of claim 1, wherein when the first input of the auxiliary power source is connected to a first positive input of the photovoltaic inverter, the second input of the auxiliary power source is connected to a second positive input of the photovoltaic inverter, and the output of the auxiliary power source is connected to a second negative input of the photovoltaic inverter; when the first end of the series switch module is connected with the first negative input end of the photovoltaic inverter and the second end of the series switch module is connected with the second positive input end of the photovoltaic inverter, the photovoltaic inverter further comprises a first diode arranged between the first input end of the auxiliary power supply and the first positive input end of the photovoltaic inverter and a second diode arranged between the second input end of the auxiliary power supply and the second positive input end of the photovoltaic inverter;
the anode end of the first diode is connected with the first anode input end of the photovoltaic inverter, and the cathode end of the first diode is connected with the first input end of the auxiliary power supply; and the anode end of the second diode is connected with the second anode input end of the photovoltaic inverter, and the cathode end of the second diode is connected with the second input end of the auxiliary power supply.
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| CN202010039933.7A CN113131509B (en) | 2020-01-15 | 2020-01-15 | Photovoltaic inverter |
| PCT/CN2020/078738 WO2021142905A1 (en) | 2020-01-15 | 2020-03-11 | Photovoltaic inverter |
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| CN202010039933.7A CN113131509B (en) | 2020-01-15 | 2020-01-15 | Photovoltaic inverter |
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| JP2013102614A (en) * | 2011-11-08 | 2013-05-23 | Panasonic Corp | Dc-dc converter |
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| WO2021142905A1 (en) | 2021-07-22 |
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