FIELD OF INVENTION
[001] The field of invention generally relates to a bi-metallic connector meant for outdoor solar applications. More specifically, the invention provides a T-shaped connector that receives multiple inputs in the form of copper cables from one or more solar strings and connects them to output aluminium cable(s).

BACKGROUND
[002] Photovoltaic (PV) cells convert sunlight into electrical energy by means of photovoltaic effect. When sunlight is incident on PV cells, it is either reflected, absorbed or passed through the cell. The absorbed sunlight generates electricity. A number of PV cells are wired in parallel to magnify current, and are wired in series to generate a higher voltage, thereby building a PV module. In a large array of PV modules, multiple solar modules are connected in series to form multiple strings. Multiple strings are then connected in parallel so as to combine the string output to create higher level current, and are forwarded to an inverter.
[003] Current systems use a string combiner box which is placed between PV modules and the inverter to bring the outputs of several solar strings together. For larger projects with a greater number of solar strings, it becomes complicated to combine the outputs of the solar strings. Each string has to be brought into the string combiner box using copper cable. Cable harness systems are used to produce a single output using copper cables. Subsequently, the electrical connections in a string combiner box need proper monitoring and maintenance to ensure high reliability. Further, since all input and output cables in the cable harness system are made of copper, there is an increase in cost of manufacturing and repair.
[004] Further systems use bimetallic connectors to connect copper cables with aluminium cables. However, the aluminium cable is placed across the copper cable and the copper cable is tapped into the aluminium cable wherever required by piercing the aluminium cable in those areas, which decreases the life of the aluminium cable, and damages the insulation of the cables.
[005] Hence, to overcome the above-mentioned problems, there is an utmost need for a device that addresses the above-mentioned problems and serves the purpose of the string combiner box without damaging the cables. Also, the device needs to be cost effective and suitable for outdoor applications as well.
OBJECT OF THE INVENTION
[006] The principal object of the invention is to provide a device that connects multiple strings from solar modules to an inverter.
[007] Another object of the invention is to provide a method of paralleling multiple copper cable strings inside a connecting device to provide at least one aluminium cable as output.
[008] Another object of the invention is to harness multiple copper cables and terminate them at a single aluminium cable.
[009] Another object of the invention is to provide a method to connect copper cables to aluminium cables, thereby reducing usage of copper cables.
[0010] Yet another object of the invention is to make the connector suitable for outdoor applications by providing UV-protection and making it waterproof.

BRIEF DESCRIPTION OF DRAWINGS
[0011] This invention is illustrated in the accompanying drawings, throughout which, like reference letters indicate corresponding parts in the various figures.
[0012] The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0013] Fig. 1 depicts/illustrates the connector connecting multiple strings from solar strings to an external unit, in accordance with an embodiment of the invention.
[0014] Fig. 2 depicts/illustrates paralleling of cables inside the connector, in accordance with an embodiment of the invention.
[0015] Fig. 3 shows a flowchart depicting/illustrating a method of yielding at least one aluminium cable output from multiple solar strings (copper cable), in accordance with an embodiment of the invention..

STATEMENT OF THE INVENTION
[0016] The present invention discloses a system and method for establishing an electrical connection between multiple solar strings from solar modules and an inverter. At least one aluminium cable output is provided from multiple input copper cables inside a “T” shaped connector. Copper cables carrying current from multiple solar strings are connected to the bimetallic connector by tapping them to the connector using a coupling unit. The coupling unit comprises male/female contacts. The connector is adapted for paralleling and terminating the copper cables from the solar strings at aluminium cables inside the connector. The connector establishes an electrical connection between the strings and an inverter, wherein the strings carry input current and the provided aluminium cable carries output current from the connector, which is further provided as input current to an inverter.

DETAILED DESCRIPTION OF INVENTION
[0017] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and/or detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0018] The embodiments below provide a bimetallic connector that connects multiple strings of photovoltaic (PV) modules to an inverter, where copper cables from the solar strings are paralleled inside the connector and terminated at an aluminium cable provided as an output. The bimetallic connector is suitable for outdoor application and is waterproof as well.
[0019] The connector is equipped with bimetallic components in a way that copper cables at an input section of the connector are converted into aluminium cables at an output section of the connector. Hence, the number of copper cables required is reduced and use of string combiner box is eliminated. Inside the connector, a single aluminium cable is run perpendicularly along the paralleled solar strings, where the aluminium cable acts as a bus bar. The connector comprises a coupling unit to couple the copper cables and the aluminium cable with a perfect male/female contact to create perfect joints that do not damage any cables.
[0020] In the present disclosure, a photovoltaic (PV) module may be referred to as a cluster of solar cells that use light energy from the sun to generate electricity through photovoltaic effect.
[0021] In the present disclosure, a solar string may be defined as a set of solar cells or modules connected in series. The solar string may also be referred to as a string.
[0022] In the present disclosure, an inverter may be defined as an electronic instrument that converts variable direct current output received from solar strings into alternating current that can be fed into a commercial electrical grid.
[0023] In the present disclosure, solar cells may be defined as a device comprising two layers made of semiconductor material such as silicon and the like, with a layer of separation between the semiconductor layers, where the three layers are wired together to build the solar cell. The solar cell may also be referred to as cell.
[0024] In the present disclosure, a bus bar may be defined as a metallic strip or bar accommodated inside a panel board and the like, to distribute local high power.
[0025] Referring now to the drawings, and more particularly to Fig. 1, where similar reference characters denote corresponding features consistently throughout the figures, preferred embodiments are shown.
[0026] Fig. 1 illustrates a ‘T’ shaped bimetallic connector 100 which comprises an input section 102, a first output section 104/1 and a second output section 104/2, as depicted. The bimetallic connector receives multiple solar string cables 110 at the input section 102.The solar string cables 110 are made of a conducting metal, preferably copper. Hereinafter, the solar string cable 110 can be referred to as copper cables 110. The first and second output sections 104/1 and 104/2 comprise output cables 120/1 and120/2. The output cables 120/1 and120/2 are made of a conducting metal other than copper, preferably aluminium.
[0027] In one embodiment, sunlight is incident on solar cells in a PV array (not shown in figure), which generates direct current electricity that is carried by solar strings comprising copper cables 110. The copper cables 110 carry the generated direct current from the solar cells to the connector 100. The copper cables 110 are attached to the connector 100 through a coupling unit (not shown in figure) comprising one or more male/female contacts incorporated in the copper cables 110 and the connector 100. Thus, the current carried by the copper cables 110 passes through the connector 100 when the copper cables 110 are attached to the connector 100 using the coupling unit. In case the copper cables 110 comprise a male connecting architecture, then the connector 100 comprises a counterpart female connecting architecture, and vice versa. The coupling is achieved using one or more of crimping, plug-in or screwing mechanism, among others. The attachment between the male and female connecting architecture results in a perfectly fitted connection, thus preventing water leakage in the connector 100.
[0028] In one embodiment, the input section is attached to the first output section and the second output section. An intersection of the input section, the first output section and the second output section can comprise a form of a shape, out of multiple shapes. In one embodiment, the input section is attached to the first output section and the second output section in a shape selected from a group comprising E-shape, F-shape, H-shape, I-shape, J-shape, T-shape, and Y-shape, among others.
[0029] The shape of the intersection can further comprise a first angle between the input section and the first output section, and a second angle between the input section and the second output section.
[0030] In one embodiment, the first angle can be similar to the second angle. In one embodiment, the first angle can be different from the second angle.
[0031] In one embodiment, the connector 100 is configured with bimetallic coupling characteristics. The input copper cables 110 are paralleled inside the connector 100 and are terminated at the output cables, namely, the aluminium output cables 120/1 and 120/2. The output aluminium cables 120/1 and 120/2 are connected to an external unit, which can be, for example, an inverter (not shown in the figure). The inverter can be used for converting direct current carried by the aluminium output cables 120/1 and 120/2 into alternating current.
[0032] In one embodiment, a metallic segment inside the connector 100 is designed to achieve the coupling process. This metal segment can be made of an aluminium alloy or any equivalent material which is suitable for conducting current between the input copper cables 110 and the aluminium output cables 120/1 and 120/2. In one preferred embodiment, the aluminium alloy can be 6061-T6 aluminium.
[0033] In one preferred embodiment, the connector 100 is a single wire. An application of approximately 1000V/1500V DC is used for paralleling of strings.
[0034] Fig. 2 illustrates a method 200 for paralleling input copper cables 110 inside the connector 100. The metal segment present inside the bimetallic connector 100 can be an aluminium bus bar 220. The copper cables 110 carrying direct current from solar strings are paralleled and terminated at the aluminium bus bar 220. The paralleling of the copper cables 110 results in multiplication of the individual currents derived from the solar strings. The multiplied individual string currents are raised to a single output current of a higher level. Consequently, the higher-level output current can be provided as an input to the inverter.
[0035] In one embodiment of the present invention, the copper cables 110 carrying direct current from multiple strings are in parallel before entering the bimetallic connector 100. In this case, the copper cables 210 are first made to be in parallel and then inputted to the bimetallic connector 100 as single copper cable that is terminated at the aluminium cable 220 inside the bimetallic connector 100.
[0036] Fig. 3 depicts a flowchart for a method for a bimetallic connector 100. The bimetallic connector 100 connects input copper cables 110 to at least one output aluminium cable 120. Copper cables 110 carrying direct current from solar strings are attached to the bimetallic connector 100 using a coupling unit comprising male or female contacts, as depicted in step 301. The copper cables 110 are made to be in parallel inside the bimetallic connector 100, as depicted in step 302. The paralleled copper cables 110 are terminated at the output aluminium cable 120 inside the bimetallic connector 100, as depicted at step 303. Subsequently, at least one output aluminium cable 120 is provided as an output from the bimetallic connector 100, as depicted at step 304. Further, the output aluminium cable 120 is connected to the inverter for converting the direct current into alternating current.
[0037] The above-mentioned system may be used as a replacement for a string combiner box for collecting an output from solar strings and connecting them to an inverter. The described embodiments provide a bimetallic connector which connects multiple input copper cables to one or two output aluminium cables. Hence, the connector reduces the number of copper cables incorporated in the entire system used for collection and conversion of sunlight into electrical energy. Thus, the overall manufacturing and repairing cost of the system is decreased, which make the system cost-effective. Additionally, the system is suitable for outdoor applications
[0038] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practised with modification within the spirit and scope of the embodiments as described herein. ,CLAIMS:CLAIMS
We claim:
1. A connector for establishing an electrical connection between solar strings from solar modules and an external unit, the connector comprising:
an input section;
the solar strings attached to the connector through the input section, wherein the solar strings are in parallel inside the connector;
a first output section and a second output section;
at least one output cable attached to at least one of the first output section and the second output section to carry output current; and
a bus bar, wherein the bus bar is adapted to terminate the in parallel solar strings at the at least one output cable.
2. The connector as claimed in claim 1, wherein the input section is attached to the first output section and the second output section; wherein a first angle between the input section and the first output section is similar to a second angle between the input section and the second output section.
3. The connector as claimed in claim 1, wherein the input section is attached to the first output section and the second output section; wherein a first angle between the input section and the first output section is different from a second angle between the input section and the second output section.
4. The connector as claimed in claim 1, wherein the input section is attached to the first output section and the second output section in form of a shape selected from the group consisting of E-shape, F-shape, H-shape, I-shape, J-shape, T-shape, and Y-shape.
5. The connector as claimed in claim 1, wherein the solar strings comprise copper cables for carrying input current.
6. The connector as claimed in claim 1, wherein the at least one output cable is an aluminium cable for carrying output current.
7. The connector as claimed in claim 1, wherein the bus bar is an aluminium bus bar.
8. The connector as claimed in claim 1, comprising one or more coupling units to couple the solar strings with the at least one output cable, wherein the coupling unit establishes an electrical connection between the solar strings and the at least one output cable.
9. The connector as claimed in claim 8, wherein the coupling unit comprises male or female contacts to attach the solar strings in to the connector.
10. The connector as claimed in claim 8, wherein the coupling unit comprises one or more of a crimping, plug-in and screwing mechanism.
11. The connector as claimed in claim 1, wherein the connector further comprises bimetallic characteristic, wherein the coupling unit comprises a material which is suitable for connecting both copper and aluminium cables, preferably aluminium alloy 6061-T6 aluminium.
12. The connector as claimed in claim 1, wherein the connector is a single wire capable of withstanding direct current of approximately 1000V to 1500V.
13. The connector as claimed in claim 1, wherein the connector is protected from Ultra Violet (UV) radiation and is waterproof.
14. The connector as claimed in claim 1, wherein the solar strings carry direct current.
15. A method for a connector for establishing an electrical connection between multiple solar strings from solar modules and an inverter, said method comprising:
attaching solar strings as an input to the connector by using a coupling unit;
arranging the solar strings in parallel inside the connector;
terminating the in parallel solar strings at an aluminium cable; and
providing at least one aluminium cable as an output from the connector.
16. The method as claimed in claim 15, further comprising terminating and paralleling the solar strings at an aluminium bus bar inside the connector.
17. The method as claimed in claim 15, further comprising attaching copper cables carrying direct current from the solar strings, to the connector through a coupling unit.
18. The method as claimed in claim 17, wherein the coupling unit comprises one or more of crimping, plug-in and screwing mechanism.
19. The method as claimed in claim 15, wherein the connector further comprises bimetallic characteristic, wherein the coupling unit comprises a material which is suitable for connecting both the copper and aluminium cables, preferably aluminium alloy 6061-T6 aluminium.
20. The method as claimed in claim 15, wherein the connector is a single wire capable of withstanding direct current of approximately 1000V to 1500V.
21. The method as claimed in claim 15, wherein the connector is protected from Ultra Violet (UV) radiation and is waterproof.