CN218633355U

CN218633355U - Photovoltaic inverter and three-phase photovoltaic inverter

Info

Publication number: CN218633355U
Application number: CN202223217262.2U
Authority: CN
Inventors: 徐�明
Original assignee: Powerland Technology Inc
Current assignee: Powerland Technology Inc
Priority date: 2022-12-01
Filing date: 2022-12-01
Publication date: 2023-03-14
Anticipated expiration: 2032-12-01

Abstract

The utility model discloses a photovoltaic inverter, including first photovoltaic board group, first switch circuit, second photovoltaic board group, second switch circuit, first switch, first inductance, second switch, first switch circuit with first photovoltaic board group is parallelly connected, first switch circuit's output warp first switch is connected to the first end of first inductance, second switch circuit with second photovoltaic board group is parallelly connected, second switch circuit's output warp second switch is connected to the first end of first inductance, first ac end is connected to the second end of first inductance, first photovoltaic board group with second photovoltaic board group's series connection mid point connects second ac end. The utility model discloses a photovoltaic inverter's circuit is simple easily controlled to very high efficiency has been reached.

Description

Photovoltaic inverter and three-phase photovoltaic inverter

Technical Field

The utility model relates to a photovoltaic board technical field that charges, and especially relate to a photovoltaic inverter and three-phase photovoltaic inverter.

Background

Solar photovoltaic panels are increasingly used because of the cleanliness and reproducibility of solar energy. Generally, direct current electric energy generated by a solar photovoltaic panel needs to be converted into alternating current electric energy through an inverter and then input into a power grid. However, due to the influence of external environmental factors and parameter differences of the photovoltaic panels, the output voltage of each photovoltaic panel is inconsistent, which brings difficulty to subsequent conversion and control.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a photovoltaic inverter has set up a Buck-Boost module for every photovoltaic board, has solved the unbalanced problem of photovoltaic board output voltage. Meanwhile, a switching circuit is arranged behind the Buck-Boost module to convert the direct current electric energy into alternating current electric energy and input the alternating current electric energy into a power grid.

In an embodiment of the present invention, the photovoltaic inverter includes a first photovoltaic panel group, a first switch circuit, a first switch, a second photovoltaic panel group, a second switch circuit, a second switch, and a first inductor, the first photovoltaic panel group includes a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected in parallel with first ends of the Buck-Boost modules, second ends of the Buck-Boost modules are connected in series, the first switch circuit includes a plurality of third switches, first ends of the third switches are respectively connected with anodes of the second ends of the Buck-Boost modules, and second ends of the third switches are connected in parallel and then connected to a first end of the first inductor through the first switch, the second photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with the first ends of the Buck-Boost modules in parallel, the second ends of the Buck-Boost modules are connected in series, the second switch circuit comprises a plurality of fourth switches, the first ends of the fourth switches are respectively connected with the negative electrodes of the second ends of the Buck-Boost modules, the second ends of the fourth switches are connected in parallel and then connected to the first end of the first inductor through the second switch, the second end of the first inductor is connected with a first alternating current end, the first photovoltaic panel group and the second photovoltaic panel group are connected in series, and the second alternating current end is connected with the series midpoint of the first photovoltaic panel group and the photovoltaic panel group.

The utility model relates to an in the embodiment of photovoltaic inverter, first photovoltaic board group includes at least 4 Buck-Boost module and at least 4 the photovoltaic board, second photovoltaic board group includes at least 4 Buck-Boost module and at least 4 the photovoltaic board.

The utility model relates to an in the embodiment of photovoltaic inverter, buck-Boost module includes fifth switch, sixth switch, seventh switch, eighth switch, second inductance, the fifth switch the sixth switch the seventh switch the eighth switch the second inductance connected mode is Buck-Boost.

In an embodiment of the photovoltaic inverter of the present invention, the first ac terminal and the second ac terminal are connected to a power grid, and the first switch is turned on to turn on a plurality of the third switches in turn during the positive half cycle of the ac voltage, so as to obtain a trapezoidal wave at the first end of the first inductor; and in the negative half cycle of the alternating voltage, the second switch is conducted, the plurality of fourth switches are conducted in turn, and the first end of the first inductor is provided with a trapezoidal wave.

The utility model relates to an in the embodiment of photovoltaic inverter, the output voltage of Buck-Boost module is stable, the third switch or the pulse width of fourth switch changes.

The utility model relates to an in the embodiment of photovoltaic inverter, the pulse width of third switch or fourth switch is fixed, the output voltage of Buck-Boost module changes.

The utility model relates to an in the embodiment of photovoltaic inverter, a photovoltaic inverter, including first photovoltaic board group, first switch, second photovoltaic board group, second switch, first inductance, first photovoltaic board group includes a plurality of Buck-Boost modules and a plurality of photovoltaic board, the photovoltaic board respectively with the first end of Buck-Boost module is parallelly connected, and is a plurality of the second end of Buck-Boost module is established ties, a plurality of first photovoltaic board group the positive pole of the second end of Buck-Boost module is passed through after the first switch is connected to the first end of first inductance, second photovoltaic board group includes a plurality of Buck-Boost modules and a plurality of photovoltaic board, the photovoltaic board respectively with the first end of Buck-Boost module is parallelly connected, and is a plurality of the second end of Buck-Boost module is established ties, a plurality of the second photovoltaic board group the negative pole of the second end of Buck-Boost module is passed through after the second switch is connected to the first end of first inductance, the first end of first inductance is connected with the second end of photovoltaic board group, the photovoltaic board group is connected with the second end of photovoltaic board is connected in series.

The utility model relates to an in the embodiment of photovoltaic inverter, first photovoltaic board group includes at least 4 Buck-Boost module and at least 4 photovoltaic board, second photovoltaic board group includes at least 4 Buck-Boost module and at least 4 photovoltaic board.

In an embodiment of the photovoltaic inverter of the present invention, the first ac terminal and the second ac terminal are connected to a power grid, and the first switch is turned on during a positive half cycle of the ac voltage, and the plurality of Buck-Boost modules in the first photovoltaic panel group operate in turn to obtain a trapezoidal wave at the first end of the first inductor; and in the negative half cycle of the alternating voltage, the second switch is conducted, the plurality of Buck-Boost modules in the second photovoltaic panel group work in turn, and trapezoidal waves are obtained at the first end of the first inductor.

The utility model relates to an in the embodiment of photovoltaic inverter, the output voltage of Buck-Boost module is stable, the operating duration of Buck-Boost module changes.

The utility model relates to an in the embodiment of photovoltaic inverter, the operating duration of Buck-Boost module is fixed, the output voltage of Buck-Boost module changes.

The present invention further provides a three-phase photovoltaic inverter apparatus, which, in an embodiment thereof, comprises a first photovoltaic panel group, a first switch circuit, a first switch, a second photovoltaic panel group, a second switch circuit, a second switch, a first inductor, a third switch circuit, a ninth switch, a fourth switch circuit, a tenth switch, a third inductor, a fifth switch circuit, an eleventh switch, a sixth switch circuit, a twelfth switch, a fourth inductor, wherein the first photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected in parallel with first ends of the Buck-Boost modules, a plurality of second ends of the Buck-Boost modules are connected in series, the first switch circuit comprises a plurality of third switches, the third switch circuit comprises a plurality of thirteenth switches, the fifth switch circuit comprises a plurality of fourteenth switches, the first ends of the third switch, the thirteenth switch and the fourteenth switch are respectively connected with the positive electrode of the second end of the Buck-Boost module, the second ends of the third switches are connected in parallel and then connected to the first end of the first inductor through the first switch, the second ends of the thirteenth switch are connected in parallel and then connected to the first end of the third inductor through the ninth switch, the second ends of the fourteenth switch are connected in parallel and then connected to the first end of the fourth inductor through the eleventh switch, the second photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected in parallel with the first ends of the Buck-Boost modules, the second ends of the Buck-Boost modules are connected in series, the second switch circuit comprises a plurality of fourth switches, the fourth switch circuit comprises a plurality of fifteenth switches, the sixth switch circuit comprises a plurality of sixteenth switches, a first end of the fourth switch, a first end of the fifteenth switch and a first end of the sixteenth switch are respectively connected with a negative electrode of a second end of the Buck-Boost module, a second end of the fourth switches are connected in parallel and then connected to a first end of the first inductor through the second switch, a second end of the fifteenth switches are connected in parallel and then connected to a first end of the third inductor through the tenth switch, and a second end of the sixteenth switches are connected in parallel and then connected to a first end of the fourth inductor through the twelfth switch, the second end of the first inductor is connected with a first alternating current end, the second end of the third inductor is connected with a third alternating current end, the second end of the fourth inductor is connected with a fifth alternating current end, the first photovoltaic panel group and the second photovoltaic panel group are connected in series, the second alternating current end, the fourth alternating current end and the sixth alternating current end are connected with the series midpoint of the first photovoltaic panel group and the second photovoltaic panel group, the first alternating current end, the third alternating current end and the fifth alternating current end are respectively a port of three-phase alternating current, and the second alternating current end, the fourth alternating current end and the sixth alternating current end are connected together to form a neutral point of three-phase alternating current.

The utility model relates to an in three-phase photovoltaic inverter's embodiment, first photovoltaic board group includes at least 4 Buck-Boost module and at least 4 the photovoltaic board, second photovoltaic board group includes at least 4 Buck-Boost module and at least 4 the photovoltaic board.

The utility model relates to an in the embodiment of three-phase photovoltaic inverter, buck-Boost module includes fifth switch, sixth switch, seventh switch, eighth switch, second inductance, the fifth switch sixth switch the seventh switch the eighth switch second inductance connected mode is Buck-Boost.

In an embodiment of the three-phase photovoltaic inverter of the present invention, the first switch is turned on during a positive half cycle of the first ac voltage, and the plurality of third switches are turned on in turn, so that a trapezoidal wave is obtained at the first end of the first inductor; in the negative half cycle of the first-phase alternating-current voltage, the second switch is conducted, the plurality of fourth switches are conducted in turn, and trapezoidal waves are obtained at the first end of the first inductor; in the positive half cycle of the second-phase alternating voltage, the ninth switch is conducted, the thirteenth switches are conducted in turn, and trapezoidal waves are obtained at the first end of the third inductor; in the negative half cycle of the second-phase alternating current voltage, the tenth switch is conducted, the fifteenth switches are conducted in turn, and trapezoidal waves are obtained at the first end of the third inductor; in the positive half cycle of the third-phase alternating-current voltage, the eleventh switch is conducted, the fourteenth switches are conducted in turn, and trapezoidal waves are obtained at the first end of the fourth inductor; and in the negative half cycle of the third-phase alternating-current voltage, the twelfth switch is conducted, the sixteenth switches are conducted in turn, and the first end of the fourth inductor is provided with a trapezoidal wave.

The utility model relates to an in the embodiment of three-phase photovoltaic inverter, the output voltage of Buck-Boost module is stable, the pulse width change of third switch or the fourth switch or the thirteenth switch or the fourteenth switch or the fifteenth switch or the sixteenth switch.

The utility model relates to an in three-phase photovoltaic inverter's embodiment, the pulse width of third switch or the fourth switch or the thirteenth switch or the fourteenth switch or the fifteenth switch or the sixteenth switch is fixed, the output voltage of Buck-Boost module changes.

In an embodiment of the three-phase photovoltaic inverter of the present invention, the three-phase photovoltaic inverter comprises a first photovoltaic panel group, a first switch, a second photovoltaic panel group, a second switch, a first inductor, a third photovoltaic panel group, a ninth switch, a fourth photovoltaic panel group, a tenth switch, a third inductor, a fifth photovoltaic panel group, an eleventh switch, a sixth photovoltaic panel group, a twelfth switch, and a fourth inductor, wherein the first photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected in parallel with first ends of the Buck-Boost modules, and second ends of the plurality of Buck-Boost modules are connected in series, the positive electrodes of the second ends of the Buck-Boost modules of the first photovoltaic panel group are connected in parallel and then connected to the first end of the first inductor through the first switch, the second photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected in parallel with the first ends of the Buck-Boost modules, the second ends of the Buck-Boost modules are connected in series, the negative electrodes of the second ends of the Buck-Boost modules of the second photovoltaic panel group are connected in parallel and then connected to the first end of the first inductor through the second switch, the second end of the first inductor is connected with a first alternating current end, the first photovoltaic panel group and the second photovoltaic panel group are connected in series, and the second alternating current end is connected with the series midpoint of the first photovoltaic panel group and the second photovoltaic panel group; the third photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with the first ends of the Buck-Boost modules in parallel, the second ends of the Buck-Boost modules are connected in series, the anodes of the second ends of the Buck-Boost modules of the third photovoltaic panel group are connected in parallel and then connected to the first end of the third inductor through the ninth switch, the fourth photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected in parallel with the first ends of the Buck-Boost modules, the second ends of the Buck-Boost modules are connected in series, the cathodes of the second ends of the Buck-Boost modules of the fourth photovoltaic panel group are connected in parallel and then connected to the first end of the third inductor through the tenth switch, the second end of the third inductor is connected to a third alternating current end, the third photovoltaic panel group is connected in series with the fourth photovoltaic panel group, and the fourth alternating current end is connected to the midpoint of the third photovoltaic panel group and the fourth photovoltaic panel group; the fifth photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with the first ends of the Buck-Boost modules in parallel, the second ends of the Buck-Boost modules are connected in series, the anodes of the second ends of the Buck-Boost modules of the fifth photovoltaic panel group are connected in parallel and then connected to the first end of the fourth inductor through the eleventh switch, the sixth photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected in parallel with the first ends of the Buck-Boost modules, the second ends of the Buck-Boost modules are connected in series, the cathodes of the second ends of the Buck-Boost modules of the sixth photovoltaic panel group are connected in parallel and then connected to the first end of the fourth inductor through the twelfth switch, the second end of the fourth inductor is connected to the fifth alternating current end, the fifth photovoltaic panel group is connected in series with the sixth photovoltaic panel group, and the sixth alternating current end is connected to the midpoint of the fifth photovoltaic panel group and the sixth photovoltaic panel group in series; the first alternating current end, the third alternating current end and the fifth alternating current end are respectively a port of three-phase alternating current, and the second alternating current end, the fourth alternating current end and the sixth alternating current end are connected together to form a neutral point of the three-phase alternating current.

The utility model relates to an in the embodiment of three-phase photovoltaic inverter, first photovoltaic board group second photovoltaic board group third photovoltaic board group fourth photovoltaic board group fifth photovoltaic board group sixth photovoltaic board group includes 4 at least respectively Buck-Boost module and 4 at least photovoltaic board.

The utility model relates to an in the embodiment of three-phase photovoltaic inverter, buck-Boost module includes fifth switch, sixth switch, seventh switch, eighth switch, second inductance, the fifth switch the sixth switch the seventh switch the eighth switch the second inductance connected mode is Buck-Boost.

In an embodiment of the three-phase photovoltaic inverter, the first switch is turned on in the positive half cycle of the first ac voltage, the plurality of Buck-Boost modules in the first photovoltaic panel group work in turn, and a trapezoidal wave is obtained at the first end of the first inductor; in the negative half cycle of the first alternating-current voltage, the second switch is conducted, the plurality of Buck-Boost modules in the second photovoltaic panel group work in turn, and a trapezoidal wave is obtained at the first end of the first inductor; in a positive half cycle of a second phase alternating current voltage, the ninth switch is conducted, the plurality of Buck-Boost modules in the third photovoltaic panel group work in turn, and a trapezoidal wave is obtained at a first end of the third inductor; in a negative half cycle of the second-phase alternating voltage, the tenth switch is switched on, the plurality of Buck-Boost modules in the fourth photovoltaic panel group work in turn, and a trapezoidal wave is obtained at the first end of the third inductor; in a positive half cycle of a third-phase alternating-current voltage, the eleventh switch is conducted, the plurality of Buck-Boost modules in the fifth photovoltaic panel group work in turn, and a trapezoidal wave is obtained at a first end of the fourth inductor; in a negative half cycle of a third-phase alternating voltage, the twelfth switch is turned on, the plurality of Buck-Boost modules in the sixth photovoltaic panel group work in turn, and a trapezoidal wave is obtained at the first end of the fourth inductor.

The utility model relates to an in the embodiment of three-phase photovoltaic inverter, the output voltage of Buck-Boost module is stable, the operating duration of Buck-Boost module changes.

The utility model relates to an in the embodiment of three-phase photovoltaic inverter, the operating duration of Buck-Boost module is fixed, the output voltage of Buck-Boost module changes.

The photovoltaic inverter has the beneficial effects that the Buck-Boost module is configured for each photovoltaic panel, so that the problem of unbalanced output voltage of the photovoltaic panels is solved; and simultaneously, the utility model discloses a photovoltaic inverter passes through control switch's break-make and produces sinusoidal alternating current, has left out the back level dc-to-ac converter, has both practiced thrift the cost, also makes the efficiency of whole device higher, the size is littleer.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is a block diagram of a first embodiment of the present invention.

Fig. 2 is a schematic circuit diagram of a first embodiment of the photovoltaic inverter apparatus in fig. 1.

Fig. 3 is a circuit diagram of the first embodiment when n =4 in fig. 2.

Fig. 4 is a diagram of the driving waveforms and the output voltage waveforms of the switch shown in fig. 3.

Fig. 5 is a schematic circuit diagram of a second embodiment of the photovoltaic inverter according to the present invention.

Fig. 6 is a block diagram of a first embodiment of the present invention.

Fig. 7 is a block diagram of a second embodiment of the present invention.

In the drawings, like reference numerals refer to the same drawing elements.

Detailed Description

In order to make the purpose and technical solution of the embodiments of the present invention clearer, the following description will clearly and completely describe the technical solution of the embodiments of the present invention by combining the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be obtained by a person skilled in the art without any inventive work based on the described embodiments of the present invention, belong to the protection scope of the present invention.

Fig. 1 shows a block diagram of a first embodiment of a photovoltaic inverter apparatus according to the present invention. As shown in fig. 1, a photovoltaic inverter device 100 includes a first photovoltaic panel group 11, a first switch circuit 12, a switch S1, a second photovoltaic panel group 21, a second switch circuit 22, a switch S2, and an inductor L1. The first photovoltaic panel group 11 provides a first group of direct current voltages, the first switch circuit 12 is connected in parallel with the first photovoltaic panel group 11 and controls the output voltage of the first photovoltaic panel group 11 to generate a trapezoidal wave, the second photovoltaic panel group 21 provides a second group of direct current voltages, the second switch circuit 22 is connected in parallel with the second photovoltaic panel group 21 and controls the output voltage of the second photovoltaic panel group 21 to generate a trapezoidal wave, the output end of the first switch circuit 12 is connected to the first end of the inductor L1 through the switch S1, the output end of the second switch circuit 22 is connected to the first end of the inductor L1 through the switch S2, the second end of the inductor L1 is connected to the first alternating current end 01, the first photovoltaic panel group 11 is connected in series with the second photovoltaic panel group 21, and the midpoint of the first switch circuit is connected to the second alternating current end 02 in series. The first photovoltaic panel group 11 and the second photovoltaic panel group 21 transmit electric energy to a power grid through a first alternating current end 01 and a second alternating current end 02, and when a switch S1 is switched on, a positive sine wave is obtained between the first alternating current end 01 and the second alternating current end 02 through filtering by an inductor L1; when the switch S2 is turned on, a negative sine wave is obtained between the first ac terminal 01 and the second ac terminal 02 through filtering by the inductor L1.

More specifically, referring to fig. 2, the first photovoltaic panel group 11 includes n Buck-Boost modules and n photovoltaic panels, preferably, the number of the Buck-Boost modules and the number of the photovoltaic panels are at least 4 respectively, the photovoltaic panel PV11 is connected in parallel with a first end of the Buck-Boost module BO11, the photovoltaic panel PV12 is connected in parallel with a first end of the Buck-Boost module BO12 until the photovoltaic panel PV1n is connected in parallel with a first end of the Buck-Boost module BO1n, and the Buck-Boost module BO11 is connected in series until a second end of the Buck-Boost module BO1 n. The Buck-Boost module regulates the output voltage of the photovoltaic panel. The first switch circuit 12 includes n switches, one end of the switch S11 is connected to a positive electrode of the second end of the Buck-Boost module BO11, the other end of the switch S11 is connected to the first end of the switch S1, one end of the switch S12 is connected to a positive electrode of the second end of the Buck-Boost module BO12, the other end of the switch S12 is connected to the first end of the switch S1 until the switch S1n, one end of the switch S1n is connected to a positive electrode of the second end of the Buck-Boost module BO1n, the other end of the switch S1n is connected to the first end of the switch S1, and the switch S11, the switch S12 until the switch S1n controls whether an output voltage V1n of the corresponding Buck-Boost module BO1n is adopted or not. The second terminal of the switch S1 is connected to the first ac terminal 01 through the inductor L1, and the switch S1 controls whether to connect the output voltage of the first photovoltaic panel group 11 to the first terminal of the inductor L1.

The second photovoltaic panel group 21 comprises n Buck-Boost modules and n photovoltaic panels, preferably, the number of the Buck-Boost modules and the number of the photovoltaic panels are at least 4 respectively, the photovoltaic panel PV21 is connected in parallel with the first end of the Buck-Boost module BO21, the photovoltaic panel PV22 is connected in parallel with the first end of the Buck-Boost module BO22 until the photovoltaic panel PV2n is connected in parallel with the first end of the Buck-Boost module BO2n, and the Buck-Boost module BO21 is connected in series until the second end of the Buck-Boost module BO2 n. The Buck-Boost module regulates the output voltage of the photovoltaic panel. The second switch circuit 22 comprises at least 4 switches, one end of the switch S21 is connected with the negative electrode of the second end of the Buck-Boost module BO21, the other end of the switch S21 is connected with the first end of the switch S2, one end of the switch S22 is connected with the negative electrode of the second end of the Buck-Boost module BO22, the other end of the switch S22 is connected with the first end of the switch S2 until the switch S2n, one end of the switch S2n is connected with the negative electrode of the second end of the Buck-Boost module BO2n, the other end of the switch S2n is connected with the first end of the switch S2, and the switch S21, the switch S22 and the switch S2n control whether the output voltage V2n of the corresponding Buck-Boost module BO2n is adopted or not. The second end of the switch S2 is connected to the first ac terminal 01 through the inductor L1, and the switch S2 controls whether to connect the output voltage of the second photovoltaic panel group 21 to the first end of the inductor L1.

The second end of the inductor L1 is connected with the first alternating current end 01, and the inductor L1 has a filtering function. The first photovoltaic panel group 11 and the second photovoltaic panel 21 are connected in series, and the series midpoint thereof is connected with the second alternating current terminal 02. When the photovoltaic panel group discharges, the switch S1 is conducted in the positive half cycle of the alternating voltage, and a positive sine wave is obtained between the first alternating current end 01 and the second alternating current end 02 after filtering through the inductor L1; in the negative half cycle of the alternating voltage, the switch S2 is turned on, and a negative sine wave is obtained between the first alternating current terminal 01 and the second alternating current terminal 02 through filtering by the inductor L1.

The circuit schematic diagram of the first embodiment of the present invention is shown in fig. 3, and 4 Buck-Boost modules and 4 photovoltaic panels are used as examples in this embodiment for explanation. The first photovoltaic panel group 11 comprises 4 Buck-Boost modules and 4 photovoltaic panels, a photovoltaic panel PV11 is connected in parallel with a first end of the Buck-Boost module BO11, a photovoltaic panel PV12 is connected in parallel with a first end of the Buck-Boost module BO12, a photovoltaic panel PV13 is connected in parallel with a first end of the Buck-Boost module BO13, a photovoltaic panel PV14 is connected in parallel with a first end of the Buck-Boost module BO14, and the Buck-Boost module BO11 is connected in series to a second end of the Buck-Boost module BO 14. The Buck-Boost module regulates the output voltage of the photovoltaic panel. The first switch circuit 12 includes 4 switches, one end of the switch S11 is connected to a positive electrode of the second end of the Buck-Boost module BO11, the other end of the switch S11 is connected to the first end of the switch S1, one end of the switch S12 is connected to a positive electrode of the second end of the Buck-Boost module BO12, the other end of the switch S12 is connected to the first end of the switch S1, one end of the switch S13 is connected to a positive electrode of the second end of the Buck-Boost module BO13, the other end of the switch S13 is connected to the first end of the switch S1, one end of the switch S14 is connected to a positive electrode of the second end of the Buck-Boost module BO14, the other end of the switch S14 is connected to the first end of the switch S1, and the switches S11, S12, S13 and S14 control whether the output voltage V1n of the corresponding Buck-Boost module BO11, buck-Boost module BO12, buck-Boost module BO13 and Buck-Boost module BO14 is adopted. The second terminal of the switch S1 is connected to the first ac terminal 01 through the inductor L1, and the switch S1 controls whether to connect the output voltage of the first photovoltaic panel group 11 to the first terminal of the inductor L1.

The second photovoltaic panel group 21 comprises 4 Buck-Boost modules and 4 photovoltaic panels, the photovoltaic panel PV21 is connected in parallel with a first end of the Buck-Boost module BO21, the photovoltaic panel PV22 is connected in parallel with a first end of the Buck-Boost module BO22, the photovoltaic panel PV23 is connected in parallel with a first end of the Buck-Boost module BO23, the photovoltaic panel PV24 is connected in parallel with a first end of the Buck-Boost module BO24, and the Buck-Boost module BO21 is connected in series to a second end of the Buck-Boost module BO 24. The Buck-Boost module regulates the output voltage of the photovoltaic panel. The second switch circuit 22 comprises 4 switches, one end of the switch S21 is connected with the negative electrode of the second end of the Buck-Boost module BO21, the other end of the switch S21 is connected with the first end of the switch S2, one end of the switch S22 is connected with the negative electrode of the second end of the Buck-Boost module BO22, the other end of the switch S22 is connected with the first end of the switch S2, one end of the switch S23 is connected with the negative electrode of the second end of the Buck-Boost module BO23, the other end of the switch S23 is connected with the first end of the switch S2, one end of the switch S24 is connected with the negative electrode of the second end of the Buck-Boost module BO24, the other end of the switch S24 is connected with the first end of the switch S2, and the switches S21, S22, S23 and S24 control whether the output voltage V2n of the corresponding Buck-Boost module BO21, buck-Boost module BO22, buck-Boost module BO23 and Buck-Boost module BO24 is adopted. The second terminal of the switch S2 is connected to the first ac terminal 01 through the inductor L1, and the switch S2 controls whether to connect the output voltage of the second photovoltaic panel group 21 to the first terminal of the inductor L1.

The second end of the inductor L1 is connected with the first alternating current end 01, and the inductor L1 has a filtering function. The first photovoltaic panel group 11 and the second photovoltaic panel group 21 are connected in series, and the series connection midpoint thereof is connected with the second alternating current terminal 02. The first photovoltaic panel group 11 and the second photovoltaic panel group 21 transmit electric energy to the power grid through the first alternating current terminal 01 and the second alternating current terminal 02.

More specifically, the Buck-Boost module is a Buck-Boost circuit, please refer to fig. 3, the Buck-Boost module BO11 includes a switch S111, a switch S112, a switch S113, a switch S114, and an inductor L11, the switch S111, the switch S112, the switch S113, the switch S114, and the inductor L11 are connected in a Buck-Boost mode, and an output end of the Buck-Boost module includes a capacitor. Similarly, the Buck-Boost modules BO12, BO13, BO14, BO21, BO22, BO23, BO24 are also Buck-Boost circuits. Controlling the Buck-Boost module to work in a Boost working mode according to the requirement, so that the output voltage of the photovoltaic panel is increased; or the Buck-Boost module is controlled to work in a Buck working mode, so that the output voltage of the photovoltaic panel is reduced. A Buck-Boost module is arranged for each photovoltaic panel, and the output voltage of each photovoltaic panel is adjusted through the Buck-Boost module, so that the problem of unbalanced output voltage of the photovoltaic panels is solved.

FIG. 4 shows the driving voltage waveforms of the switches S11, S12, S13, S14 and the voltage waveform V between the first terminal and the second AC terminal 02 of the inductor L1 in FIG. 3 _AC In fig. 4, the horizontal axis t represents time in milliseconds. At a voltage V _AC In the positive half cycle, the switch S1 is conducted, the switch S14, the switch S13, the switch S12, the switch S11, the switch S12, the switch S13 and the switch S14 are conducted in turn, and the voltage V _AC A positive trapezoidal wave, switch S11 is turned on and voltage V _AC Equal to V11+ V12+ V13+ V14, the switch S12 is turned on and the voltage V is _AC Equal to V12+ V13+ V14, the switch S13 is turned on, the voltage V _AC Equal to V13+ V14, the switch S14 is turned on and the voltage V _AC Equal to V14; at a voltage V _AC In the negative half cycle, the switch S2 is turned on, and the switch S21, the switch S22, the switch S23, the switch S24, the switch S23, the switch S22 and the switch S21 are turned on in turn, so that a negative trapezoidal wave is obtained between the first end and the second ac end 02 of the inductor L1, as shown by the waveform V in fig. 4 _AC Switch S21 is shown to be on, with voltage V _AC Equal to-V21, switch S22 is turned on, voltage V _AC Equal to-V21-V22, the switch S23 is turned on, and the voltage V is _AC Equal to-V21-V22-V23, the switch S24 is turned on, and the voltage V _AC Equal to-V21-V22-V23-V24.

The utility model relates to a photovoltaic inverter inputs the electric energy into the electric wire netting through first AC end 01 and second AC end 02, and in positive half cycle of alternating voltage, switch S1 switches on, switches S11-S14 are switched on in turn, obtains trapezoidal wave at the first end of inductance L1, and the concrete time sequence is as shown in figure 4; and in the negative half cycle of the alternating voltage, the switch S2 is conducted, the switches S21-S24 are conducted in turn, and the trapezoidal wave is obtained at the first end of the inductor L1. After filtering by the inductor L1, a sinusoidal ac voltage is obtained between the first ac terminal 01 and the second ac terminal 02, and the fundamental voltage value of the generated sinusoidal ac voltage can be adjusted in two ways. One way is that under the condition that the output voltage of each Buck-Boost module is fixed, the control switch S11, the switch S12, the switch S13 and the switch are controlled to be openedThe pulse widths of the switch S14, the switch S21, the switch S22, the switch S23 and the switch S24 are turned off to regulate the voltage V _AC A fundamental wave voltage value; in another mode, under the condition that the pulse widths of the switch S11, the switch S12, the switch S13, the switch S14, the switch S21, the switch S22, the switch S23 and the switch S24 are fixed, the output voltage of each Buck-Boost module is controlled to regulate the voltage V _AC The fundamental voltage value.

Since the sine wave is gradually approximated by the trapezoidal wave, if the order of the trapezoidal wave is too small, the inductance value of the inductor L1 is large, that is, the size of the inductor L1 is large. The problem can be solved by increasing the order of the trapezoidal wave and reducing the output voltage of the Buck-Boost module.

When the alternating current frequency is 50Hz, the switching frequency of the switch S1 and the switch S2 is 50Hz, and the switching frequency of the switch S11, the switch S12, the switch S13, the switch S14, the switch S21, the switch S22, the switch S23 and the switch S24 is 100Hz. Because the frequency of switch is very low, the utility model discloses a photovoltaic board inverter has the efficiency of superelevation.

In a second embodiment of the present invention, please refer to fig. 5, the photovoltaic inverter includes a first photovoltaic panel set 11, a switch S1, a second photovoltaic panel set 21, a switch S2, and an inductor L1. The first photovoltaic panel group 11 comprises at least 4 Buck-Boost modules and at least 4 photovoltaic panels and the second photovoltaic panel group 21 comprises at least 4 Buck-Boost modules and at least 4 photovoltaic panels. Fig. 5 shows a schematic circuit diagram of a first photovoltaic panel group 11 comprising 4 Buck-Boost modules BO11 to BO14 and 4 photovoltaic panels PV11 to PV14, a second photovoltaic panel group 21 comprising 4 Buck-Boost modules BO21 to BO24 and 4 photovoltaic panels PV21 to PV 24.

The first photovoltaic panel group 11 comprises 4 Buck-Boost modules and 4 photovoltaic panels, the photovoltaic panel PV11 is connected in parallel with a first end of the Buck-Boost module BO11, a positive electrode of a second end of the Buck-Boost module BO11 is connected with a first end of the switch S1, the photovoltaic panel PV12 is connected in parallel with the first end of the Buck-Boost module BO12, a positive electrode of the second end of the Buck-Boost module BO12 is connected with the first end of the switch S1, the photovoltaic panel PV13 is connected in parallel with the first end of the Buck-Boost module BO13, a positive electrode of the second end of the Buck-Boost module BO13 is connected with the first end of the switch S1, the photovoltaic panel PV14 is connected in parallel with the first end of the Buck-Boost module 14, a positive electrode of the second end of the Buck-Boost module BO14 is connected with the first end of the switch S1, and the Buck-Boost module BO11 is connected in series to the second end of the Buck-Boost module BO 14. The Buck-Boost module regulates the output voltage of the photovoltaic panel. The second terminal of the switch S1 is connected to the first ac terminal 01 through the inductor L1, and the switch S1 controls whether to connect the output voltage of the first photovoltaic panel group 11 to the first terminal of the inductor L1.

The second photovoltaic panel group 21 comprises 4 Buck-Boost modules and 4 photovoltaic panels, the photovoltaic panel PV21 is connected in parallel with a first end of the Buck-Boost module BO21, a negative electrode of a second end of the Buck-Boost module BO21 is connected with a first end of the switch S2, the photovoltaic panel PV22 is connected in parallel with a first end of the Buck-Boost module BO22, a negative electrode of a second end of the Buck-Boost module BO22 is connected with a first end of the switch S2, the photovoltaic panel PV23 is connected in parallel with a first end of the Buck-Boost module BO23, a negative electrode of a second end of the Buck-Boost module BO23 is connected with a first end of the switch S2, the photovoltaic panel PV24 is connected in parallel with a first end of the Buck-Boost module BO24, a negative electrode of a second end of the Buck-Boost module BO24 is connected with a first end of the switch S2, and the Buck-Boost module BO21 is connected in series to the second end of the Buck-Boost module BO 24. The Buck-Boost module regulates the output voltage of the photovoltaic panel. The second terminal of the switch S2 is connected to the first ac terminal 01 through the inductor L1, and the switch S2 controls whether to connect the output voltage of the second photovoltaic panel group 21 to the first terminal of the inductor L1.

The second end of the inductor L1 is connected with the first alternating current end 01, and the inductor L1 has a filtering function. The first photovoltaic panel group 11 and the second photovoltaic panel group 21 are connected in series, and the series connection midpoint thereof is connected with the second alternating current terminal 02. The utility model relates to a photovoltaic inverter inputs the electric energy into the electric wire netting through first alternating current end 01 and second alternating current end 02, and in the positive half cycle of alternating voltage, switch S1 switches on, through inductance L1 filtering, obtains positive sine wave between first alternating current end 01 and second alternating current end 02; in the negative half cycle of the alternating voltage, the switch S2 is turned on, and a negative sine wave is obtained between the first alternating current terminal 01 and the second alternating current terminal 02 through filtering by the inductor L1.

More specifically, the Buck-Boost module is a Buck-Boost circuit, please refer to fig. 5, the Buck-Boost module BO11 includes a switch S111, a switch S112, a switch S113, a switch S114, and an inductor L11, the switch S111, the switch S112, the switch S113, the switch S114, and the inductor L11 are connected in a Buck-Boost mode, and an output end of the Buck-Boost module includes a capacitor. Similarly, the Buck-Boost modules BO12, BO13, BO14, BO21, BO22, BO23, BO24 are also Buck-Boost circuits. Controlling the Buck-Boost module to work in a Boost working mode according to the requirement, so that the output voltage of the photovoltaic panel is increased; or the Buck-Boost module is controlled to work in a Buck working mode, so that the output voltage of the photovoltaic panel is reduced. A Buck-Boost module is arranged for each photovoltaic panel, and the output voltage of each photovoltaic panel is adjusted through the Buck-Boost module, so that the problem of unbalanced output voltage of the photovoltaic panels is solved.

In the positive half cycle of the alternating current voltage, the switch S1 is conducted, the Buck-Boost modules BO14, BO13, BO12, BO11, BO12, BO13 and BO14 work in turn and output direct current voltage, and a positive trapezoidal wave is obtained between the first end and the second alternating current end 02 of the inductor L1; in the negative half cycle of the alternating current voltage, the switch S2 is conducted, the Buck-Boost modules BO21, BO22, BO23, BO24, BO23, BO22 and BO21 work in turn and output the direct current voltage, and a negative trapezoidal wave is obtained between the first end and the second alternating current end 02 of the inductor L1. After filtering by the inductor L1, a sinusoidal ac voltage is obtained between the first ac terminal 01 and the second ac terminal 02.

The utility model provides a three-phase photovoltaic board inverter, its first concrete embodiment' S block diagram is shown in fig. 6, a three-phase photovoltaic board inverter 600, including first photovoltaic board group 11, first switch circuit 12, switch S1, second photovoltaic board group 21, second switch circuit 22, switch S2, inductance L1, third switch circuit 13, switch S3, fourth switch circuit 23, switch S4, inductance L2, fifth switch circuit 14, switch S5, sixth switch circuit 24, switch S6, inductance L3. The first photovoltaic panel group 11 provides a first group of direct-current voltages, and the first switching circuit 12 is connected in parallel with the first photovoltaic panel group 11, controls the output voltage of the first photovoltaic panel group 11 and generates a first-phase positive trapezoidal wave; the third switch circuit 13 is connected in parallel with the first photovoltaic panel group 11, and controls the output voltage of the first photovoltaic panel group 11 and generates a positive trapezoidal wave of a second phase; a fifth switching circuit 14 is connected in parallel with the first group of photovoltaic panels 11, and controls the output voltage of the first group of photovoltaic panels 11 and generates a positive trapezoidal wave of the third phase. The second photovoltaic panel group 21 provides a second group of direct current voltages, and the second switching circuit 22 is connected in parallel with the second photovoltaic panel group 21, and controls the output voltage of the second photovoltaic panel group 21 and generates a negative trapezoidal wave of the first phase; the fourth switch circuit 23 is connected in parallel with the second photovoltaic panel group 21, and controls the output voltage of the second photovoltaic panel group 21 and generates a negative trapezoidal wave of the second phase; a sixth switching circuit 24 is connected in parallel with the second photovoltaic panel group 21, and controls the output voltage of the second photovoltaic panel group 21 and generates a negative trapezoidal wave of the third phase. The output end of the first switch circuit 12 is connected to the first end of the inductor L1 through the switch S1, the output end of the second switch circuit 22 is connected to the first end of the inductor L1 through the switch S2, the second end of the inductor L1 is connected to the first ac terminal 01, the first photovoltaic panel group 11 is connected in series with the second photovoltaic panel group 21, and the series midpoint thereof is connected to the second ac terminal 02; the output end of the third switch circuit 13 is connected to the first end of the inductor L2 through the switch S3, the output end of the fourth switch circuit 23 is connected to the first end of the inductor L2 through the switch S4, the second end of the inductor L2 is connected to the third ac terminal 03, and the series midpoint of the first photovoltaic panel group 11 and the second photovoltaic panel group 21 is connected to the fourth ac terminal 04; the output terminal of the fifth switching circuit 14 is connected to the first terminal of the inductor L3 through the switch S5, the output terminal of the sixth switching circuit 24 is connected to the first terminal of the inductor L3 through the switch S6, the second terminal of the inductor L3 is connected to the fifth ac terminal 05, and the series midpoint of the first photovoltaic panel group 11 and the second photovoltaic panel group 21 is connected to the sixth ac terminal 06. The first alternating current terminal 01, the third alternating current terminal 03 and the fifth alternating current terminal 05 are respectively a port of three-phase alternating current, and the second alternating current terminal 02, the fourth alternating current terminal 04 and the sixth alternating current terminal 06 are connected together to form a neutral point of the three-phase alternating current. The specific connection mode and the operation principle of each phase circuit are the same as those of the first embodiment of the photovoltaic inverter device in fig. 3, and are not described herein again.

The utility model relates to a block diagram of the specific embodiment of three-phase photovoltaic board inverter second is shown in fig. 7, a three-phase photovoltaic board inverter 700, including first photovoltaic board group 11, switch S1, second photovoltaic board group 21, switch S2, inductance L1, third photovoltaic board group 31, switch S3, fourth photovoltaic board group 41, switch S4, inductance L2, fifth photovoltaic board group 51, switch S5, sixth photovoltaic board group 61, switch S6, inductance L3. The first photovoltaic panel group 11 provides a positive trapezoidal wave of the first phase and is connected to the first end of the inductor L1 through the switch S1, the second photovoltaic panel group 21 provides a negative trapezoidal wave of the first phase and is connected to the first end of the inductor L1 through the switch S2, the second end of the inductor L1 is connected to the first alternating current end 01, the first photovoltaic panel group 11 is connected with the second photovoltaic panel group 21 in series, and the series middle point of the first photovoltaic panel group is connected to the second alternating current end 02; the third photovoltaic panel group 31 provides a positive trapezoidal wave of the second phase and is connected to the first end of the inductor L2 through the switch S3, the fourth photovoltaic panel group 41 provides a negative trapezoidal wave of the second phase and is connected to the first end of the inductor L2 through the switch S4, the second end of the inductor L2 is connected to the third ac terminal 03, the third photovoltaic panel group 31 is connected in series with the fourth photovoltaic panel group 41, and the series midpoint thereof is connected to the fourth ac terminal 04; the fifth photovoltaic panel group 51 provides a positive trapezoidal wave of the third phase and is connected to the first end of the inductor L3 through the switch S5, the sixth photovoltaic panel group 61 provides a negative trapezoidal wave of the third phase and is connected to the first end of the inductor L3 through the switch S6, the second end of the inductor L3 is connected to the fifth ac terminal 05, and the fifth photovoltaic panel group 51 is connected in series with the sixth photovoltaic panel group 61, and the series midpoint thereof is connected to the sixth ac terminal 06. The first alternating current terminal 01, the third alternating current terminal 03 and the fifth alternating current terminal 05 are respectively a port of three-phase alternating current, and the second alternating current terminal 02, the fourth alternating current terminal 04 and the sixth alternating current terminal 06 are connected together to form a neutral point of the three-phase alternating current. The specific connection manner and the operation principle of each phase circuit are the same as those of the second embodiment of the photovoltaic inverter device in fig. 5, and are not described herein again.

Although the present invention has been described with reference to the above embodiments, it is not intended to limit the present invention to the details of construction and operation of the devices and methods disclosed herein, and modifications and variations of the embodiments may be made without departing from the spirit and scope of the invention.

Claims

1. A photovoltaic inverter is characterized by comprising a first photovoltaic panel group, a first switch circuit, a first switch, a second photovoltaic panel group, a second switch circuit, a second switch and a first inductor, wherein the first photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with the first ends of the Buck-Boost modules in parallel, the second ends of the Buck-Boost modules are connected in series, the first switch circuit comprises a plurality of third switches, the first ends of the third switches are respectively connected with the anodes of the second ends of the Buck-Boost modules, the second ends of the third switches are connected in parallel and then connected to the first end of the first inductor through the first switch, the second photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with the first ends of the Buck-Boost modules in parallel, the second ends of the Buck-Boost modules are connected in series, the second switch circuit comprises a plurality of fourth switches, the first ends of the fourth switches are respectively connected with the negative electrodes of the second ends of the Buck-Boost modules, the second ends of the fourth switches are connected in parallel and then connected to the first end of the first inductor through the second switch, the second end of the first inductor is connected with a first alternating current end, the first photovoltaic panel group and the second photovoltaic panel group are connected in series, and the second alternating current end is connected with the series midpoint of the first photovoltaic panel group and the photovoltaic panel group.

2. A photovoltaic inversion device according to claim 1, wherein the first photovoltaic panel group includes at least 4 of the Buck-Boost modules and at least 4 of the photovoltaic panels, and the second photovoltaic panel group includes at least 4 of the Buck-Boost modules and at least 4 of the photovoltaic panels.

3. The photovoltaic inverter device according to claim 2, wherein the Buck-Boost module comprises a fifth switch, a sixth switch, a seventh switch, an eighth switch and a second inductor, and the fifth switch, the sixth switch, the seventh switch, the eighth switch and the second inductor are connected in a Buck-Boost manner.

4. The inverter as claimed in claim 3, wherein the first ac terminal and the second ac terminal are connected to a power grid, and the first switch is turned on during positive half cycle of the ac voltage to turn on the plurality of third switches in turn, thereby obtaining a trapezoidal wave at the first terminal of the first inductor; and in the negative half cycle of the alternating voltage, the second switch is conducted, the plurality of fourth switches are conducted in turn, and the first end of the first inductor is provided with a trapezoidal wave.

5. The photovoltaic inverter device according to claim 4, wherein an output voltage of the Buck-Boost module is stable, and a pulse width of the third switch or the fourth switch is varied.

6. The photovoltaic inverter device according to claim 4, wherein the pulse width of the third switch or the fourth switch is fixed, and the output voltage of the Buck-Boost module varies.

7. A photovoltaic inverter device is characterized by comprising a first photovoltaic panel group, a first switch, a second photovoltaic panel group, a second switch and a first inductor, wherein the first photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with first ends of the Buck-Boost modules in parallel, second ends of the Buck-Boost modules are connected in series, positive electrodes of second ends of the Buck-Boost modules of the first photovoltaic panel group are connected with first ends of the first inductors through the first switch after being connected in parallel, the second photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with first ends of the Buck-Boost modules in parallel, second ends of the Buck-Boost modules are connected with second ends of the Buck-Boost modules in series, negative electrodes of second ends of the Buck-Boost modules of the second photovoltaic panel group are connected with first ends of the first inductors through the second switch after being connected in parallel, the first ends of the first inductors are connected with second ends of the first photovoltaic panel group, the second ends of the first photovoltaic panel group are connected with second photovoltaic panel group in series, and the second ends of the second photovoltaic panel group are connected with alternating current ends of the second photovoltaic panel group, and the alternating current end of the second photovoltaic panel group, and the first inductor are connected with alternating current point.

8. The photovoltaic inverter apparatus of claim 7, wherein the first photovoltaic panel group comprises at least 4 Buck-Boost modules and at least 4 photovoltaic panels, and the second photovoltaic panel group comprises at least 4 Buck-Boost modules and at least 4 photovoltaic panels.

9. The photovoltaic inverter device according to claim 8, wherein the Buck-Boost module comprises a fifth switch, a sixth switch, a seventh switch, an eighth switch and a second inductor, and the fifth switch, the sixth switch, the seventh switch, the eighth switch and the second inductor are connected in a Buck-Boost manner.

10. The photovoltaic inverter according to claim 9, wherein the first ac terminal and the second ac terminal are connected to a power grid, the first switch is turned on during a positive half cycle of the ac voltage, and the plurality of Buck-Boost modules in the first photovoltaic panel group operate in turn to obtain a trapezoidal wave at the first terminal of the first inductor; and in the negative half cycle of the alternating voltage, the second switch is conducted, the plurality of Buck-Boost modules in the second photovoltaic panel group work in turn, and trapezoidal waves are obtained at the first end of the first inductor.

11. The photovoltaic inverter device according to claim 10, wherein an output voltage of the Buck-Boost module is stable, and an operation time of the Buck-Boost module varies.

12. The photovoltaic inverter according to claim 10, wherein the Buck-Boost module has a fixed operating time, and an output voltage of the Buck-Boost module varies.

13. A three-phase photovoltaic inverter device is characterized by comprising a first photovoltaic panel group, a first switch circuit, a first switch, a second photovoltaic panel group, a second switch circuit, a second switch, a first inductor, a third switch circuit, a ninth switch, a fourth switch circuit, a tenth switch, a third inductor, a fifth switch circuit, an eleventh switch, a sixth switch circuit, a twelfth switch and a fourth inductor, wherein the first photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with the first ends of the Buck-Boost modules in parallel, the second ends of the Buck-Boost modules are connected in series, the first switch circuit comprises a plurality of third switches, the third switch circuit comprises a plurality of thirteenth switches, and the fifth switch circuit comprises a plurality of fourteenth switches, the first ends of the third switch, the thirteenth switch and the fourteenth switch are respectively connected with the positive electrode of the second end of the Buck-Boost module, the second ends of the third switches are connected in parallel and then connected to the first end of the first inductor through the first switch, the second ends of the thirteenth switch are connected in parallel and then connected to the first end of the third inductor through the ninth switch, the second ends of the fourteenth switch are connected in parallel and then connected to the first end of the fourth inductor through the eleventh switch, the second photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected in parallel with the first ends of the Buck-Boost modules, the second ends of the Buck-Boost modules are connected in series, the second switch circuit comprises a plurality of fourth switches, and the fourth switch circuit comprises a plurality of fifteenth switches, the sixth switch circuit comprises a plurality of sixteenth switches, wherein a first end of the fourth switch, a first end of the fifteenth switch and a first end of the sixteenth switch are respectively connected with a negative electrode of a second end of the Buck-Boost module, a second end of the plurality of fourth switches is connected to the first end of the first inductor through the second switch after being connected in parallel, a second end of the plurality of fifteenth switches is connected to the first end of the third inductor through the tenth switch after being connected in parallel, and a second end of the plurality of sixteenth switches is connected to the first end of the fourth inductor through the twelfth switch after being connected in parallel, the second end of the first inductor is connected with a first alternating current end, the second end of the third inductor is connected with a third alternating current end, the second end of the fourth inductor is connected with a fifth alternating current end, the first photovoltaic panel group and the second photovoltaic panel group are connected in series, the second alternating current end, the fourth alternating current end and the sixth alternating current end are connected with the series midpoint of the first photovoltaic panel group and the second photovoltaic panel group, the first alternating current end, the third alternating current end and the fifth alternating current end are respectively a port of three-phase alternating current, and the second alternating current end, the fourth alternating current end and the sixth alternating current end are connected together to be a neutral point of the three-phase alternating current.

14. A three-phase photovoltaic inverter apparatus according to claim 13, wherein the first group of photovoltaic panels comprises at least 4 of the Buck-Boost modules and at least 4 of the photovoltaic panels, and the second group of photovoltaic panels comprises at least 4 of the Buck-Boost modules and at least 4 of the photovoltaic panels.

15. The three-phase photovoltaic inverter device according to claim 14, wherein the Buck-Boost module includes a fifth switch, a sixth switch, a seventh switch, an eighth switch, and a second inductor, and the fifth switch, the sixth switch, the seventh switch, the eighth switch, and the second inductor are connected in a Buck-Boost manner.

16. The apparatus according to claim 15, wherein the first switch is turned on during a positive half cycle of the first ac voltage, and a plurality of the third switches are turned on in turn, so that a trapezoidal wave is obtained at the first end of the first inductor; in the negative half cycle of the first-phase alternating-current voltage, the second switch is conducted, the plurality of fourth switches are conducted in turn, and trapezoidal waves are obtained at the first end of the first inductor; in the positive half cycle of the second-phase alternating voltage, the ninth switch is conducted, the thirteenth switches are conducted in turn, and trapezoidal waves are obtained at the first end of the third inductor; in the negative half cycle of the second-phase alternating current voltage, the tenth switch is conducted, the fifteenth switches are conducted in turn, and trapezoidal waves are obtained at the first end of the third inductor; in the positive half cycle of the third-phase alternating-current voltage, the eleventh switch is conducted, the fourteenth switches are conducted in turn, and trapezoidal waves are obtained at the first end of the fourth inductor; and in the negative half cycle of the third-phase alternating-current voltage, the twelfth switch is switched on, the sixteenth switches are switched on in turn, and the first end of the fourth inductor is provided with a trapezoidal wave.

17. The apparatus of claim 16, wherein an output voltage of the Buck-Boost module is stable, and a pulse width of the third switch, the fourth switch, the thirteenth switch, the fourteenth switch, the fifteenth switch, or the sixteenth switch is varied.

18. The apparatus according to claim 16, wherein the third switch, the fourth switch, the thirteenth switch, the fourteenth switch, the fifteenth switch or the sixteenth switch has a fixed pulse width, and the output voltage of the Buck-Boost module varies.

19. A three-phase photovoltaic inverter is characterized by comprising a first photovoltaic panel group, a first switch, a second photovoltaic panel group, a second switch, a first inductor, a third photovoltaic panel group, a ninth switch, a fourth photovoltaic panel group, a tenth switch, a third inductor, a fifth photovoltaic panel group, an eleventh switch, a sixth photovoltaic panel group, a twelfth switch and a fourth inductor, wherein the first photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with the first ends of the Buck-Boost modules in parallel, the second ends of the Buck-Boost modules are connected in series, the anodes of the second ends of the Buck-Boost modules of the first photovoltaic panel group are connected in parallel and then connected with the first end of the first inductor through the first switch, the second photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with the first ends of the Buck-Boost modules in parallel, the second ends of the Buck-Boost modules are connected in series, the cathodes of the second ends of the Buck-Boost modules of the second photovoltaic panel group are connected in parallel and then connected to the first end of the first inductor through the second switch, the second end of the first inductor is connected with a first alternating current end, the first photovoltaic panel group is connected with the second photovoltaic panel group in series, and the second alternating current end is connected with the series midpoint of the first photovoltaic panel group and the second photovoltaic panel group; the third photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with the first ends of the Buck-Boost modules in parallel, the second ends of the Buck-Boost modules are connected in series, the anodes of the second ends of the Buck-Boost modules of the third photovoltaic panel group are connected in parallel and then connected to the first end of the third inductor through the ninth switch, the fourth photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected in parallel with the first ends of the Buck-Boost modules, the second ends of the Buck-Boost modules are connected in series, the cathodes of the second ends of the Buck-Boost modules of the fourth photovoltaic panel group are connected in parallel and then connected to the first end of the third inductor through the tenth switch, the second end of the third inductor is connected to a third alternating current end, the third photovoltaic panel group is connected in series with the fourth photovoltaic panel group, and the fourth alternating current end is connected to the midpoint of the third photovoltaic panel group and the fourth photovoltaic panel group; the fifth photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected with the first ends of the Buck-Boost modules in parallel, the second ends of the Buck-Boost modules are connected in series, the anodes of the second ends of the Buck-Boost modules of the fifth photovoltaic panel group are connected in parallel and then connected to the first end of the fourth inductor through the eleventh switch, the sixth photovoltaic panel group comprises a plurality of Buck-Boost modules and a plurality of photovoltaic panels, the photovoltaic panels are respectively connected in parallel with the first ends of the Buck-Boost modules, the second ends of the Buck-Boost modules are connected in series, the cathodes of the second ends of the Buck-Boost modules of the sixth photovoltaic panel group are connected in parallel and then connected to the first end of the fourth inductor through the twelfth switch, the second end of the fourth inductor is connected to the fifth alternating current end, the fifth photovoltaic panel group is connected in series with the sixth photovoltaic panel group, and the sixth alternating current end is connected to the midpoint of the fifth photovoltaic panel group and the sixth photovoltaic panel group in series; the first alternating current end, the third alternating current end and the fifth alternating current end are respectively a port of three-phase alternating current, and the second alternating current end, the fourth alternating current end and the sixth alternating current end are connected together to form a neutral point of the three-phase alternating current.

20. The three-phase photovoltaic inverter device according to claim 19, wherein the first, second, third, fourth, fifth and sixth photovoltaic panels comprise at least 4 Buck-Boost modules and at least 4 photovoltaic panels, respectively.

21. The three-phase photovoltaic inverter device according to claim 20, wherein the Buck-Boost module comprises a fifth switch, a sixth switch, a seventh switch, an eighth switch, and a second inductor, and the fifth switch, the sixth switch, the seventh switch, the eighth switch, and the second inductor are connected in a Buck-Boost manner.

22. The apparatus according to claim 21, wherein the first switch is turned on during a positive half cycle of the first ac voltage, and the plurality of Buck-Boost modules in the first photovoltaic panel group operate in turn to obtain a trapezoidal wave at the first end of the first inductor; in the negative half cycle of the first alternating-current voltage, the second switch is conducted, the plurality of Buck-Boost modules in the second photovoltaic panel group work in turn, and a trapezoidal wave is obtained at the first end of the first inductor; in the positive half cycle of the second phase alternating voltage, the ninth switch is conducted, the plurality of Buck-Boost modules in the third photovoltaic panel group work in turn, and trapezoidal waves are obtained at the first end of the third inductor; in a negative half cycle of the second-phase alternating voltage, the tenth switch is switched on, the plurality of Buck-Boost modules in the fourth photovoltaic panel group work in turn, and a trapezoidal wave is obtained at the first end of the third inductor; in a positive half cycle of a third-phase alternating-current voltage, the eleventh switch is turned on, the plurality of Buck-Boost modules in the fifth photovoltaic panel group work in turn, and a trapezoidal wave is obtained at a first end of the fourth inductor; in a negative half cycle of a third-phase alternating voltage, the twelfth switch is turned on, the plurality of Buck-Boost modules in the sixth photovoltaic panel group work in turn, and a trapezoidal wave is obtained at the first end of the fourth inductor.

23. The apparatus according to claim 22, wherein the Buck-Boost module has a stable output voltage, and the Buck-Boost module has a variable operation time.

24. The apparatus according to claim 22, wherein the Buck-Boost module has a fixed operating time, and an output voltage of the Buck-Boost module varies.