CN114498733A - Connecting circuit and photovoltaic inverter system - Google Patents

Abstract

The invention provides a communication circuit and a photovoltaic inversion system, wherein the communication circuit is connected between a photovoltaic group string and the inverter system, the inverter system comprises a plurality of boosting circuits with output ends connected in parallel, the communication circuit comprises at least one multi-connected module, the input end of the multi-connected module is connected with one photovoltaic group string, the output ends of the multi-connected module are respectively and correspondingly connected with the input ends of the plurality of boosting circuits, and the plurality of boosting circuits are controlled as one MPPT circuit. Through setting up and ally oneself with the module more, can parallelly connected back and a photovoltaic group cluster with the boost circuit that the module was connected more to can reduce the quantity of the photovoltaic group cluster of connecting, the event can adopt the bigger single photovoltaic group cluster of group cluster electric current, need not to adjust or change inverter system internal part device simultaneously, the cost is reduced.

Description

Connecting circuit and photovoltaic inverter system

technical field

The invention relates to the field of circuit design, in particular to a connecting circuit and a photovoltaic inverter system.

Background technique

In the prior art, the BOOST circuit in the photovoltaic inverter system is correspondingly connected to a group of photovoltaic strings to form a photovoltaic inverter system. However, since the maximum current of the strings that can be connected to the photovoltaic inverter system is limited, it is necessary to connect For larger current PV strings, it is necessary to adjust or replace the internal components of the inverter system, which is costly.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a connecting circuit and a photovoltaic inverter system, which aims to solve the problem that the photovoltaic inverter system in the prior art is relatively expensive to connect a photovoltaic string with a larger current.

In order to achieve the above object, the present invention provides a communication circuit, the communication circuit is connected between a photovoltaic string and an inverter system, the inverter system includes a plurality of boost circuits whose output terminals are connected in parallel, and the communication circuit is The circuit includes at least one multi-connected module, the input end of the multi-connected module is connected to one of the photovoltaic strings in series, and the multiple output ends of the multi-connected module are respectively connected to the input ends of the plurality of boost circuits correspondingly, wherein, The multiple boost circuits are controlled as one MPPT circuit.

Optionally, the multi-connected module includes two connectors, wherein the positive connector connected between the positive electrode of the photovoltaic string and the positive input end of the booster circuit is a positive connector, which is connected to the photovoltaic array. Between the negative pole of the string and the negative input end of the boost circuit is a negative pole connector; wherein:

The connector includes an input port for connecting with the photovoltaic string, and the connector also includes a plurality of output ports for connecting with the boost circuit.

Optionally, the communication circuit further includes a single-connected module, the input end of the single-connected module is connected to any photovoltaic string in the photovoltaic string not connected to the multi-connected module, and the output end is connected to the One booster circuit among the multiple booster circuits controlled by one MPPT circuit is connected.

In addition, in order to achieve the above object, the present invention also provides a photovoltaic inverter system, the photovoltaic inverter system includes a multi-channel photovoltaic string, an inverter system, and a connection circuit according to any one of claims 1 to 3. .

Optionally, the boost circuit includes multiple pairs of connection interfaces, each pair of connection interfaces includes a positive interface and a negative interface; the multi-connection module includes a positive connector and a negative connector; the boost circuit passes through the The positive interface is connected to the positive connector, and the booster circuit is connected to the negative connector through the negative connector.

Optionally, the communication circuit further includes a single-connected module, the input end of the single-connected module is connected to one of the photovoltaic strings that is not connected to the multi-connected module, and the output end of the single-connected module is connected to the A pair of connection interfaces that are not connected to the multi-connected module in the plurality of boosting circuits are connected.

Optionally, the photovoltaic inverter system includes both a first connection scheme and a second connection scheme, wherein:

The first connection scheme is that several photovoltaic strings are connected to multiple boost circuits through a combination of multi-connected modules and single-connected modules, wherein the multiple boost circuits are connected in parallel through the multiple-connected modules, and serve as one MPPT circuit. to control;

The second connection scheme is that other photovoltaic strings that are not connected to the first connection scheme are connected to any other booster circuit that is not connected to the first connection scheme, wherein the first connection scheme is not connected to the first connection. Any one of the booster circuits in the scheme is controlled as a MPPT circuit.

Optionally, the photovoltaic string includes a first photovoltaic string and a second photovoltaic string, the boost circuit includes a first boost circuit and a second boost circuit, the first boost circuit and the second boost circuit The booster circuit includes two positive ports and two negative ports respectively; the multi-connected module includes a first multi-connected module and a second multi-connected module, the first multi-connected module and the second multi-connected module. The connecting modules respectively include two Y-shaped connectors, the Y-shaped connectors include one input end and two output ends; the first multi-connected module includes a first positive Y-shaped connector and a first negative Y-shaped connector ; The second multi-connection module includes a second positive Y-shaped connector and a second negative Y-shaped connector; wherein:

The input end of the first positive Y-connector is connected to the positive electrode of the first photovoltaic string, and the input end of the first negative Y-connector is connected to the negative electrode of the first photovoltaic string; the The input end of the second positive Y-connector is connected to the positive electrode of the second photovoltaic string, and the input end of the second negative Y-connector is connected to the negative electrode of the second photovoltaic string;

The first positive interface of the first boost circuit is connected to the first output end of the first positive Y-connector, and the first positive interface of the second boost circuit is connected to the first positive Y-connector The second output terminal of the first booster circuit is connected to the first output terminal of the second positive Y-connector, and the second positive terminal of the second booster circuit is connected to the first output terminal of the second positive Y-connector the second output end of the second positive Y-connector is connected;

The first negative interface of the first boost circuit is connected to the first output end of the first negative Y-type connector, and the first negative interface of the second boost circuit is connected to the first negative Y-type connector The second output terminal of the first booster circuit is connected to the second output terminal of the Y-connector; the second negative terminal of the second booster circuit is connected to the first output terminal of the second negative Y-connector. The second output end of the second negative Y-connector is connected.

Optionally, the photovoltaic string includes a first photovoltaic string, a second photovoltaic string and a third photovoltaic string, the boost circuit includes a first boost circuit and a second boost circuit, the first boost circuit The booster circuit and the second booster circuit respectively comprise two positive terminals and two negative terminals; the multi-connection module comprises two Y-connectors, which are a first positive Y-connector and a first positive Y-connector respectively. A negative Y-shaped connector, the Y-shaped connector includes an input end and two output ends; the communication circuit also includes two single-connection modules, which are a first single-connection module and a second single-connection module, the first single-connection module and the second single-connection module are respectively. The single-connection module includes a first positive type-1 connector and a first negative-electrode-type connector, and the second single-connection module includes a second positive-connector type-1 connector and a second negative electrode-type connector, wherein:

The first positive terminal of the first boost circuit is connected to the positive terminal of the first photovoltaic string through the first positive terminal type connector, and the first negative terminal of the first boost circuit is connected to the positive terminal of the first photovoltaic string through the first positive terminal. A negative pole type 1 connector is connected to the negative pole of the first photovoltaic string; the first positive interface of the second booster circuit is connected to the positive pole of the second photovoltaic string through the second positive pole type 1 connector connection, the first negative interface of the second booster circuit is connected to the negative electrode of the second photovoltaic string through the second negative electrode type 1 connector;

The second positive interface of the first boost circuit is connected to the first output end of the first positive Y-connector, and the second positive interface of the second boost circuit is connected to the first positive Y-connector The second output terminal of the first voltage booster circuit is connected to the second output terminal of the first voltage booster circuit; the second output end of the first negative Y-connector is connected;

The input end of the first positive Y-connector is connected to the positive electrode of the third photovoltaic string; the input end of the first negative Y-connector is connected to the negative electrode of the third photovoltaic string.

Optionally, the inverter system includes the boost circuit and an inverter, an output end of the boost circuit is connected to an input end of the inverter, and an output end of the inverter serves as the The output of the inverter system.

The present invention proposes a communication circuit and a photovoltaic inverter system. The communication circuit is connected between a photovoltaic string and an inverter system. The inverter system includes a plurality of boost circuits whose output terminals are connected in parallel. The communication circuit includes at least one multi-connected module, the input end of the multi-connected module is connected to one of the photovoltaic strings, and the multiple output ends of the multi-connected module are respectively connected to the input ends of the plurality of boost circuits, wherein , the multiple boost circuits are controlled as one MPPT circuit. By setting up multi-connected modules, the booster circuits connected by the multi-connected modules can be connected in parallel with one PV string, thereby reducing the number of connected PV strings. Therefore, a single PV string with a larger string current can be used. At the same time, there is no need to adjust or replace the internal components of the inverter system, which reduces the cost.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained according to the structures shown in these drawings without creative efforts.

1 is a functional block diagram of an embodiment of a communication circuit according to the present invention;

FIG. 2 is a functional block diagram of another embodiment of a communication circuit according to the present invention;

3 is a circuit structure diagram of an embodiment of the photovoltaic inverter system of the present invention;

4 is a circuit structure diagram of an embodiment of the photovoltaic inverter system of the present invention;

FIG. 5 is a circuit structure diagram of an embodiment of the photovoltaic inverter system of the present invention.

The realization, functional characteristics and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments.

Description of reference numbers:

label name label name 100 Multi-connection module 101 Positive connector 102 Negative connector

Detailed ways

It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the The relative positional relationship between the components, the movement situation, etc., if the specific posture changes, the directional indication also changes accordingly.

In addition, the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes, and should not be understood as indicating or implying their relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of such technical solutions does not exist. , is not within the scope of protection required by the present invention.

The present invention provides a connection circuit, which is applied to a photovoltaic inverter system. Please refer to FIG. 1 . FIG. 1 is a functional block diagram of an embodiment of the connection circuit of the present invention. In this embodiment, the communication circuit is connected between the photovoltaic string and the inverter system, and the inverter system includes a plurality of boost circuits whose output terminals are connected in parallel. It should be noted that, as shown in FIG. 1 The boost circuit is a typical BOOST circuit commonly used in photovoltaic inverter systems, but those of ordinary skill in the art should know that the boost circuit can be any other DC power conversion circuit with boost function, which is not limited in the present invention. . The communication circuit includes at least one multi-connected module 100, the input end of the multi-connected module 100 is connected to one photovoltaic string, and the multiple output ends of the multi-connected module 100 correspond to the input ends of the multiple boost circuits respectively. connection, wherein the plurality of boosting circuits are controlled as one MPPT circuit.

A photovoltaic string refers to a circuit unit with a certain DC output formed by connecting several photovoltaic modules in series in a photovoltaic power generation system.

The specific inverter system structure can be set according to actual application scenarios and needs, which is not limited here; exemplarily, the inverter system includes an inverter and a plurality of booster circuits, and the input end of each booster circuit is connected to a communication circuit The output ends of each booster circuit are respectively connected with the input ends of the inverters, and the output ends of the inverters are used as the output ends of the inverter system.

The multi-connected module 100 connects the connected booster circuits together in parallel, and connects to the same PV string, and at the same time, these parallel booster circuits are controlled as an MPPT (Maximum Power Point Tracking, maximum power point tracking) circuit. The multi-connected module 100 includes a plurality of output terminals, one output terminal is connected to one booster circuit, and different booster circuits are connected to different output terminals.

It should be noted that the number of booster circuits that can be connected to one multi-connection module 100 can be set according to the number of booster circuits in the inverter system, the actual application scenario, and needs. The number of multi-connection modules 100 is also set according to actual application scenarios and needs.

By setting the multi-connected module 100 in this embodiment, multiple boost circuits connected to the multiple-connected module 100 can be connected in parallel to the same photovoltaic string, and the multiple boost circuits can be combined into one MPPT for control. Therefore, without adding or changing the internal components of the photovoltaic inverter system, the number of connected photovoltaic strings can be reduced, and the current of the MPPT circuit can be increased, so a single photovoltaic string with a larger string current can be used. There is no need to adjust or replace the internal components of the inverter system, which reduces the cost.

Further, referring to FIG. 2 , the multi-connected module 100 includes two connectors, wherein the positive connector 110 is connected between the positive electrode of the photovoltaic string and the positive input end of the booster circuit. Between the negative electrode of the photovoltaic string and the negative input end of the booster circuit is the negative electrode connector 120; wherein:

The connector includes an input port for connecting with the photovoltaic string, and the connector also includes a plurality of output ports for connecting with the boost circuit.

It can be understood that the output of the photovoltaic string is DC, and the boost circuit also requires the input to be DC input. Therefore, the photovoltaic string has a positive pole and a negative pole, and the booster circuit has a positive input terminal and a negative input terminal; set the positive connector 110 to connect The anode of the photovoltaic string and the anode input of the booster circuit are provided with a cathode connector 120 to connect the cathode of the photovoltaic string and the cathode input of the booster circuit.

The connector includes an input end and a plurality of output ends, the input end and each output end are connected to each other, each output end is connected to a booster circuit, and the booster circuits connected to different output ends are different. It can be understood that the number of the output terminals of the through-connector is greater than 1 and less than or equal to the number of the booster circuits.

Since the output terminals of the connector need to be connected to different boosting circuits, the maximum number of output terminals of the connector is the number of boosting circuits. It can be understood that the number of output ends of the connector is an integer, that is, the number of output ends of the connector is at least 2. It should be noted that this embodiment only takes the example of completely connecting the output ends of the connector. In practical applications, a connector with a number of output ends greater than the number of boost circuits can be used, but only a connector whose number is less than or equal to the number of boost circuits can be used. The output terminals of the number of booster circuits are connected to each booster circuit; if the number of output terminals of the connector is 4 and the number of boosters is 3, the connector can also be used, and only the 3 output ends on the connector are respectively connected with each other. The booster circuit is connected, or the two output terminals on the connector are respectively connected to two of the booster circuits, and the output terminal that is not connected to the booster circuit is empty.

Further, the communication circuit also includes a single-connected module, the input end of the single-connected module is connected to any photovoltaic string in the photovoltaic string not connected to the multi-connected module, and the output end is connected to the one-way MPPT control. One of the plurality of booster circuits is connected.

It should be noted that the single-connection module can be an in-line connector, or a wire; the in-line connector includes an input end and an output end, and the input end of the in-line connector is connected to the photovoltaic string, and the in-line connector includes an input end and an output end. The output end of the connector is connected with the booster circuit.

This embodiment can reasonably reduce the number of photovoltaic strings that need to be connected through the multi-connected module 100 .

In addition, the present invention also protects a photovoltaic inverter system, which includes a photovoltaic string, an inverter system, and the above-mentioned connecting circuit. The structure of the connecting circuit can refer to the above-mentioned embodiment, which is not repeated here. Repeat. As a matter of course, since the photovoltaic inverter system of this embodiment adopts the technical solution of the above-mentioned connected circuit, the photovoltaic inverter system has all the beneficial effects of the above-mentioned connected circuit.

Further, the boost circuit includes multiple pairs of connection interfaces, each pair of connection interfaces includes a positive interface and a negative interface; the multi-connection module includes a positive connector and a negative connector; the boost circuit passes through the positive connector. The interface is connected to the positive connector, and the booster circuit is connected to the negative connector through the negative connector.

The number of pairs of connection interfaces of the booster circuit can be set according to actual application scenarios and needs, and is not limited here.

Further, the communication circuit further includes a single-connected module, the input end of the single-connected module is connected to one of the photovoltaic strings not connected to the multi-connected module, and the output end of the single-connected module is connected to the A pair of the plurality of boosting circuits is not connected to the connection interface of the multi-connected module.

The single-connected module connects the connected booster circuit with the PV string. It should be noted that the single-connection module can be an in-line connector, or a wire; the in-line connector includes an input end and an output end, and the input end of the in-line connector is connected to the photovoltaic string, and the in-line connector includes an input end and an output end. The output end of the connector is connected with the booster circuit.

The connection structure of the photovoltaic inverter system in several cases is selected as an example to illustrate:

Referring to Fig. 3, the number of booster circuits is two, the number of connection interface pairs is two, the number of multi-connected modules is two, and the number of output ends of the connector in the multi-connected module is two, that is, the connector is Y type connector, the number of PV strings is two as an example:

The photovoltaic string includes a first photovoltaic string P1 and a second photovoltaic string P2, the booster circuit includes a first booster circuit and a second booster circuit, the first booster circuit and the second booster circuit The circuits respectively include two of the positive ports and two of the negative ports; the multi-connected modules include a first multi-connected module 101 and a second multi-connected module 102 , the first multi-connected module 101 and the second multi-connected module 101 The multi-connected modules 102 respectively include two Y-shaped connectors, and the Y-shaped connectors include one input end and two output ends; the first multi-connected module 101 includes a first positive Y-shaped connector 111 and a first negative electrode Y-shaped connector 112; the second multi-connection module 102 includes a second positive Y-shaped connector 121 and a second negative Y-shaped connector 122; wherein:

The input end of the first positive Y-connector 111 is connected to the positive electrode of the first photovoltaic string P1, and the input end of the first negative Y-connector 112 is connected to the negative electrode of the first photovoltaic string P1 connection; the input end of the second positive Y-type connector 121 is connected to the positive electrode of the second photovoltaic string P2, and the input end of the second negative Y-type connector 122 is connected to the second photovoltaic string P2 negative connection of ;

The first positive terminal A of the first boost circuit is connected to the first output end of the first positive Y-connector 111, and the first positive terminal D of the second boost circuit is connected to the first positive terminal The second output terminal of the Y-type connector 111 is connected; the second positive terminal B of the first boost circuit is connected to the first output terminal of the second positive Y-type connector 121, and the second boost circuit The second positive port C is connected to the second output end of the second positive Y-connector 121;

The first negative terminal A- of the first boost circuit is connected to the first output end of the first negative Y-connector 112, and the first negative terminal D- of the second boost circuit is connected to the first output terminal of the first negative Y-connector 112. The second output end of a negative Y-connector 112 is connected; the second negative interface B- of the first boost circuit is connected to the first output end of the second negative Y-connector 122, and the second negative interface B- The second negative terminal C- of the booster circuit is connected to the second output terminal of the second negative Y-connector 122 .

Since the first boost circuit and the second boost circuit are connected in parallel through multi-connected modules and are controlled as a channel of MPPT, the maximum current allowed by the MPPT circuit at this time is I _MPPT = 2I _BOOST , and I _BOOST is a boost circuit of one channel maximum current allowed. When the booster circuit and PV strings are connected only through a single module, the number of PV strings is 4, and each booster circuit is connected with two PV strings, that is, the maximum current allowed for each PV string is I _pv =I _BOOST /2, that is, I _MPPT =2I _BOOST =4I _pv . When connected by the above connection method, the number of photovoltaic strings is reduced to 2, so the maximum current allowed by each photovoltaic string is I _MPPT /2=2I _pv .

Referring to Figure 4, the number of booster circuits is two, the number of connection interface pairs is two, the number of multi-connected modules is one, and the number of output terminals of the connector in the multi-connected module is two, that is, the connector is Y-shaped For the connector, the number of single-connected modules is two, and the number of PV strings is three. For example:

The photovoltaic string includes a first photovoltaic string P1, a second photovoltaic string P2 and a third photovoltaic string P3, and the booster circuit includes a first booster circuit and a second booster circuit. The voltage circuit and the second booster circuit respectively include two positive terminals and two negative terminals; the multi-connection module comprises two Y-connectors, which are the first positive Y-connector 111 and the first positive Y-connector 111 respectively. The negative Y-connector 112, the Y-connector includes one input end and two output ends; the communication circuit also includes two single-connection modules, which are the first single-connection module 210 and the second single-connection module 220 respectively. , the first single-connection module 210 includes a first positive electrode type 1 connector 211 and a first negative electrode type 1 connector 212, and the second single-connection module 220 includes a second positive electrode type 1 connector 221 and a second negative electrode type 1 connector 222 ,in:

The first positive terminal A of the first booster circuit is connected to the positive terminal of the first photovoltaic string P1 through the first positive terminal 211, and the first negative terminal A of the first booster circuit is connected to the positive terminal of the first photovoltaic string P1. - Connect to the negative pole of the first photovoltaic string P1 through the first negative pole type 1 connector 212 ; the first positive pole interface C of the second boost circuit is connected to the second positive pole type 1 connector 221 The positive pole of the third photovoltaic string P3 is connected, and the first negative interface C- of the second booster circuit is connected to the negative pole of the third photovoltaic string P3 through the second negative pole type 1 connector 222;

The second positive terminal B of the first booster circuit is connected to the first output end of the first positive Y-connector 111, and the second positive terminal D of the second booster circuit is connected to the first positive terminal The second output terminal of the Y-shaped connector 111 is connected; the second negative terminal B- of the first booster circuit is connected to the first output terminal of the first negative Y-shaped connector 112, and the second voltage booster The second negative terminal D- of the circuit is connected to the second output terminal of the first negative Y-connector 112;

The input end of the first positive Y-connector 111 is connected to the positive electrode of the second photovoltaic string P2; the input end of the first negative Y-connector 112 is connected to the negative electrode of the second photovoltaic string P2 connect.

Since the first boost circuit and the second boost circuit are connected in parallel through multi-connected modules and are controlled as a channel of MPPT, the maximum current allowed by the MPPT circuit at this time is I _MPPT = 2I _BOOST , and I _BOOST is a boost circuit of one channel maximum current allowed. When the booster circuit and PV strings are connected only through a single module, the number of PV strings is 4, and each booster circuit is connected with two PV strings, that is, the maximum current allowed for each PV string is I _pv =I _BOOST /2, that is, I _MPPT =2I _BOOST =4I _pv . When connected by the above connection method, the number of PV strings is reduced to 3, so the maximum current allowed by each PV string is I _MPPT /3=4I _pv /3.

Referring to Fig. 5, the number of booster circuits is two, the number of connection interface pairs is three, the number of multi-connected modules is two, and the number of output terminals of the connector in the multi-connected module is two, that is, the connector is Y type connector, the number of single-connected modules is two, and the number of PV strings is four, for example:

The photovoltaic string includes a first photovoltaic string P1, a second photovoltaic string P2, a third photovoltaic string P3 and a fourth photovoltaic string P4, and the boost circuit includes a first boost circuit and a second boost circuit circuit, the first boost circuit and the second boost circuit respectively include three of the positive ports and three of the negative ports; the multi-connected module includes a first multi-connected module 101 and a second multi-connected module 102 , the first multi-connection module 101 and the second multi-connection module 102 respectively include two Y-shaped connectors, and the Y-shaped connector includes an input end and two output ends; the first multi-connection module 101 includes a first positive Y-connector 111 and a first negative Y-connector 112; the second multi-connection module 102 includes a second positive Y-connector 121 and a second negative Y-connector 122; the communication The circuit also includes two single-connected modules, namely a first single-connected module 210 and a second single-connected module 220. The first single-connected module 210 includes a first positive pole type 1 connector 211 and a first negative pole type 1 connector 212. The second single-connection module 220 includes a second positive pole type 1 connector 221 and a second negative pole type 1 connector 222, wherein:

The first positive terminal A of the first booster circuit is connected to the positive terminal of the first photovoltaic string P1 through the first positive terminal 211, and the first negative terminal A of the first booster circuit is connected to the positive terminal of the first photovoltaic string P1. - Connect to the negative pole of the first photovoltaic string P1 through the first negative pole type 1 connector 212 ; the first positive pole interface D of the second boost circuit is connected to the second positive pole type 1 connector 221 The positive pole of the fourth photovoltaic string P4 is connected, and the first negative interface D- of the second boost circuit is connected to the negative pole of the fourth photovoltaic string P4 through the second negative pole type 1 connector 222;

The second positive terminal B of the first boost circuit is connected to the first output end of the first positive Y-connector 111, and the second positive terminal E of the second boost circuit is connected to the first positive terminal The second output terminal of the Y-connector 111 is connected; the third positive terminal C of the first booster circuit is connected to the first output terminal of the second positive Y-connector 121, and the second booster circuit The third positive port F is connected to the second output end of the second positive Y-type connector 121;

The second negative terminal B- of the first boost circuit is connected to the first output end of the first negative Y-connector 112, and the second negative terminal E- of the second boost circuit is connected to the first output terminal of the first negative Y-connector 112. The second output end of a negative Y-connector 112 is connected; the third negative interface C- of the first boost circuit is connected to the first output end of the second negative Y-connector 122, and the second negative connector C- The third negative terminal F- of the booster circuit is connected to the second output terminal of the second negative Y-connector 122 .

The input end of the first positive Y-connector 111 is connected to the positive electrode of the second photovoltaic string P2; the input end of the first negative Y-connector 112 is connected to the negative electrode of the second photovoltaic string P2 connection; the input end of the second positive Y-shaped connector 121 is connected to the positive electrode of the third photovoltaic string P3; the input end of the second negative Y-shaped connector 122 is connected to the third photovoltaic string P3 negative connection.

Since the first boost circuit and the second boost circuit are connected in parallel through multi-connected modules and are controlled as a channel of MPPT, the maximum current allowed by the MPPT circuit at this time is I _MPPT = 2I _BOOST , and I _BOOST is a boost circuit of one channel maximum current allowed. When the booster circuit and the PV strings are connected only through a single module, the number of PV strings is 6, and each booster circuit is connected with two PV strings, that is, the maximum current allowed for each PV string is I _pv =I _BOOST /3, that is, I _MPPT =2I _BOOST =6I _pv . When connected by the above connection method, the number of photovoltaic strings is reduced to 4, so the maximum current allowed by each photovoltaic string is I _MPPT /4=3I _pv /2.

It should be noted that the above is only an example, and the number of single-connected modules and multi-connected modules in the photovoltaic inverter system and the specific connection relationship can be set according to actual needs. The setting logic in this embodiment can be summarized as follows:

When only the single-connected module is used to connect the photovoltaic string and the booster circuit, it can be equivalent to the connection method in the prior art; on this basis, the connectors in the multi-connected modules are fully connected, that is, each output of the connector is fully connected. For example, both terminals are connected to a booster circuit; each time a single-connection module is replaced by a multi-connected module and connected between the PV string and the booster circuit, the number of PV strings will be reduced, and the specific reduction is as follows: The number of output terminals of a single connector in the module is -1; for example, the number of booster circuits is 3, and each booster circuit includes 3 positive input terminals and 3 negative input terminals. In this way, the number of PV strings to be connected is 9. At this time, a multi-connected module with an output terminal of 3 is used to replace the three single-connected modules, and the number of PV strings to be connected is 7. The number of PV strings is 3-1=2. If the six single-connected modules are replaced by multi-connected modules with two connectors whose output terminals are 3, the number of PV strings to be connected is 5, and the number of PV strings is reduced. The number of is 2*(3-1)=4.

As mentioned above, several photovoltaic strings are connected to multiple boost circuits through the combination of multi-connected modules and single-connected modules, and the multiple boost circuits are connected in parallel and controlled as one MPPT. This connection scheme It is called the first connection scheme. In addition, several other photovoltaic strings are connected to any booster circuit that is not connected to the first connection scheme, and this booster circuit is controlled as one MPPT. This connection scheme is called the second connection scheme. In some embodiments, for the same photovoltaic inverter system, it can be connected only according to the first connection scheme; it can also be mixed according to the first connection scheme and the second connection scheme, on the one hand, it supports access to a larger group On the other hand, the number of MPPT circuits can be flexibly adjusted for PV strings with string current, making power regulation more accurate and efficient.

It should be noted that the number of pairs of connection interfaces of each booster circuit in the inverter system may be different, and the number of output terminals of the connectors in each multi-connected module used may also be different.

In this embodiment, the number of photovoltaic strings is reduced by arranging multiple modules, so that the maximum current of a single photovoltaic string allowed to be connected to the photovoltaic inverter system is increased without increasing or changing the internal components of the photovoltaic inverter system. The PV inverter system can support PV strings with higher power and higher current.

It should be noted that, herein, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article or system comprising a series of elements includes not only those elements, It also includes other elements not expressly listed or inherent to such a process, method, article or system. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in the process, method, article or system that includes the element. The above-mentioned serial numbers of the embodiments of the present invention are only for description, and do not represent the advantages or disadvantages of the embodiments.

The above are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields , are similarly included in the scope of patent protection of the present invention.

Claims (10)

1. The utility model provides a intercommunication circuit, its characterized in that, the intercommunication circuit is connected between photovoltaic group cluster and contravariant system, contravariant system includes the parallelly connected booster circuit that is in the same place of a plurality of output, the intercommunication circuit includes that at least one allies oneself with the module more, ally oneself with the input of module more with all the way photovoltaic group series connection, a plurality of outputs of module more correspond with a plurality of booster circuit's input respectively and are connected, wherein, a plurality of booster circuit control as MPPT circuit all the way.

2. The communication circuit of claim 1, wherein the multi-connected module comprises two communicators, wherein the communicator connected between the positive pole of the photovoltaic string and the positive input of the boost circuit is a positive communicator, and the communicator connected between the negative pole of the photovoltaic string and the negative input of the boost circuit is a negative communicator; wherein:

the communicator comprises an input port connected with the photovoltaic group in series, and a plurality of output ports connected with the boosting circuit.

3. The pass-through circuit of claim 1, further comprising a single-gang module having an input connected to any one of the strings of photovoltaic strings not connected to the multi-gang module and an output connected to one of the plurality of boost circuits that is controlled as a MPPT circuit.

4. A photovoltaic inversion system, comprising a plurality of photovoltaic strings, an inversion system and the communication circuit of any one of claims 1 to 3.

5. The photovoltaic inverter system of claim 4, wherein the boost circuit comprises a plurality of pairs of connection interfaces, each pair of connection interfaces comprising a positive interface and a negative interface; the multi-connected module comprises a positive electrode communicating vessel and a negative electrode communicating vessel; the booster circuit is connected with the positive communicating vessel through the positive interface, and the booster circuit is connected with the negative communicating vessel through the negative interface.

6. The pv inversion system of claim 5, wherein the pass-through circuit further comprises a simplex module, an input of the simplex module is connected to one of the pv strings not connected to the multiplex module, and an output of the simplex module is connected to a pair of connection interfaces not connected to the multiplex module in the plurality of boost circuits.

7. The photovoltaic inversion system of claim 6, comprising both the first connection scheme and the second connection scheme, wherein:

the first connection scheme is that a plurality of photovoltaic group strings are connected with a plurality of booster circuits through the combination of a multi-connection module and a single-connection module, wherein the plurality of booster circuits are connected in parallel through the multi-connection module and are controlled as one MPPT circuit;

the second connection scheme is that other photovoltaic string which is not accessed to the first connection scheme is connected with any other booster circuit which is not accessed to the first connection scheme, wherein the any booster circuit which is not accessed to the first connection scheme is controlled as one path of MPPT circuit.

8. The photovoltaic inversion system of claim 5, wherein the photovoltaic string comprises a first photovoltaic string and a second photovoltaic string, the boost circuit comprises a first boost circuit and a second boost circuit, the first boost circuit and the second boost circuit respectively comprise two of the positive interfaces and two of the negative interfaces; the multi-connected module comprises a first multi-connected module and a second multi-connected module, the first multi-connected module and the second multi-connected module respectively comprise two Y-shaped communicators, and each Y-shaped communicator comprises an input end and two output ends; the first multi-connected module comprises a first anode Y-shaped communicating vessel and a first cathode Y-shaped communicating vessel; the second multi-connected module comprises a second positive Y-shaped communicating vessel and a second negative Y-shaped communicating vessel; wherein:

the input end of the first positive Y-shaped communicating vessel is connected with the positive electrode of the first photovoltaic string, and the input end of the first negative Y-shaped communicating vessel is connected with the negative electrode of the first photovoltaic string; the input end of the second positive Y-shaped communicating vessel is connected with the positive electrode of the second photovoltaic string, and the input end of the second negative Y-shaped communicating vessel is connected with the negative electrode of the second photovoltaic string;

a first positive electrode interface of the first booster circuit is connected with a first output end of the first positive electrode Y-shaped communicating vessel, and a first positive electrode interface of the second booster circuit is connected with a second output end of the first positive electrode Y-shaped communicating vessel; a second positive electrode interface of the first booster circuit is connected with a first output end of the second positive electrode Y-shaped communicating vessel, and a second positive electrode interface of the second booster circuit is connected with a second output end of the second positive electrode Y-shaped communicating vessel;

a first negative electrode interface of the first booster circuit is connected with a first output end of the first negative electrode Y-shaped communicating vessel, and a first negative electrode interface of the second booster circuit is connected with a second output end of the first negative electrode Y-shaped communicating vessel; and a second negative electrode interface of the first booster circuit is connected with a first output end of the second negative electrode Y-shaped communicating vessel, and a second negative electrode interface of the second booster circuit is connected with a second output end of the second negative electrode Y-shaped communicating vessel.

9. The photovoltaic inversion system of claim 5, wherein the photovoltaic string comprises a first photovoltaic string, a second photovoltaic string, and a third photovoltaic string, the boost circuit comprises a first boost circuit and a second boost circuit, the first boost circuit and the second boost circuit respectively comprise two of the positive interfaces and two of the negative interfaces; the multi-connected module comprises two Y-shaped communicators, namely a first anode Y-shaped communicator and a first cathode Y-shaped communicator, wherein the Y-shaped communicators comprise an input end and two output ends; the intercommunication circuit still includes two simply-connected modules, is first simply-connected module and second simply-connected module respectively, and first simply-connected module includes first anodal a type linker and first negative pole a type linker, and the second simply-connected module includes second anodal a type linker and second negative pole a type linker, wherein:

a first positive electrode interface of the first booster circuit is connected with a positive electrode of the first photovoltaic string through the first positive electrode one-type communicating device, and a first negative electrode interface of the first booster circuit is connected with a negative electrode of the first photovoltaic string through the first negative electrode one-type communicating device; a first positive electrode interface of the second booster circuit is connected with the positive electrode of the second photovoltaic string through the second positive electrode one-type communicator, and a first negative electrode interface of the second booster circuit is connected with the negative electrode of the second photovoltaic string through the second negative electrode one-type communicator;

a second positive electrode interface of the first booster circuit is connected with a first output end of the first positive electrode Y-shaped communicating vessel, and a second positive electrode interface of the second booster circuit is connected with a second output end of the first positive electrode Y-shaped communicating vessel; a second negative electrode interface of the first booster circuit is connected with a first output end of the first negative electrode Y-shaped communicating vessel, and a second negative electrode interface of the second booster circuit is connected with a second output end of the first negative electrode Y-shaped communicating vessel;

the input end of the first positive electrode Y-shaped communicating vessel is connected with the positive electrode of the third photovoltaic string; and the input end of the first negative electrode Y-shaped communicating vessel is connected with the negative electrode of the third photovoltaic group string.

10. The photovoltaic inversion system of claim 4, wherein the inversion system comprises the boost circuit and an inverter, an output of the boost circuit is connected to an input of the inverter, and an output of the inverter is used as an output of the inversion system.

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