CA2762078A1 - Modular electrical connector apparatus and method for rapid assembly of photovoltaic arrays - Google Patents
Modular electrical connector apparatus and method for rapid assembly of photovoltaic arrays Download PDFInfo
- Publication number
- CA2762078A1 CA2762078A1 CA 2762078 CA2762078A CA2762078A1 CA 2762078 A1 CA2762078 A1 CA 2762078A1 CA 2762078 CA2762078 CA 2762078 CA 2762078 A CA2762078 A CA 2762078A CA 2762078 A1 CA2762078 A1 CA 2762078A1
- Authority
- CA
- Canada
- Prior art keywords
- electrical
- terminals
- box
- boxes
- satisfy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 10
- 238000003491 array Methods 0.000 title claims description 33
- 238000010276 construction Methods 0.000 claims description 9
- 230000006835 compression Effects 0.000 claims description 8
- 238000007906 compression Methods 0.000 claims description 8
- 238000009429 electrical wiring Methods 0.000 claims description 7
- 238000002955 isolation Methods 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 2
- 229910052751 metal Inorganic materials 0.000 claims description 2
- 239000000463 material Substances 0.000 claims 2
- 239000011152 fibreglass Substances 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 23
- 238000013461 design Methods 0.000 description 11
- 238000009434 installation Methods 0.000 description 9
- 238000012544 monitoring process Methods 0.000 description 9
- 238000001514 detection method Methods 0.000 description 7
- 238000011144 upstream manufacturing Methods 0.000 description 3
- 241000723347 Cinnamomum Species 0.000 description 2
- 235000017803 cinnamon Nutrition 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000005405 multipole Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 208000014797 chronic intestinal pseudoobstruction Diseases 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000009432 framing Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012806 monitoring device Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
- H01L31/042—PV modules or arrays of single PV cells
- H01L31/05—Electrical interconnection means between PV cells inside the PV module, e.g. series connection of PV cells
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
- H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
- H02S40/30—Electrical components
- H02S40/34—Electrical components comprising specially adapted electrical connection means to be structurally associated with the PV module, e.g. junction boxes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Photovoltaic Devices (AREA)
Abstract
An electrical combiner box apparatus is disclosed with electrical terminals designed for rapid connection to photovoltaic modules. In addition, the combiner box includes electrical terminals designed to allow rapid connection to similar combiner boxes along a common electrical bus.
Methods are disclosed using the apparatus to rapidly assemble systems of multiple solar photovoltaic modules of arbitrary size and arrangement.
Methods are disclosed using the apparatus to rapidly assemble systems of multiple solar photovoltaic modules of arbitrary size and arrangement.
Description
FIELD
The invention pertains generally to electrical wiring, connectors, terminals and boxes, and particularly to those devices for use with solar photovoltaic modules and related electrical systems.
BACKGROUND
Solar photovoltaic modules (or panels) produce DC electrical power that is collected through wiring commonly attached to the back of the module. Multiple modules may be connected together to produce greater power. A plurality of modules connected in this fashion is commonly referred to as an array. To facilitate the rapid assembly of arrays, modules are commonly equipped with locking quick-connect electrical fittings. Among many such designs, Tyco and MC4 connectors are common.
Due to limitations, both physical and electrical, large arrays are often made up of several smaller arrays known as strings. Strings are then wired together electrically to produce the array.
The division into strings may be related to the physical layout of the array, for instance, when modules have to be separated to fit around an air conditioner unit on a roof.
In this case weatherproof enclosures known as junction boxes or chock boxes can be used to combine the wiring of the strings back together.
It is also common to use strings to keep the electrical wiring below prescribed voltage or current limits, or to limit short-circuit current flow. To protect against this possibility, the array is divided into strings and the strings are then isolated using circuit protection devices such as fuses or circuit breakers. These are commonly found in load centers, fuse boxes or combiner boxes; herein collectively referred to as combiners.
Common examples of junction boxes and combiners are not designed specifically for use in the solar industry. Generally, they are designed to connect using terminal block, wire nuts ("Marettes") or similar systems designed to connect to bare wire. Connecting a string to the combiner is thus a time consuming process, requires several tools, additional parts, and generally has to be carried out by a licensed electrician.
If the array requires more strings than a given combiner supports, multiple combiners are wired together. Known combiners lack any system for rapid interconnection, and labor-intensive wiring techniques like those for string connection are needed. Larger combiners with more terminals are also available, but often impractical due to their size, cost, and the need to run the wiring from the strings to the central location of the combiner.
Accordingly, what is desired is an improved junction/combiner system for the rapid assemblage of strings and arrays. Ideally, no tools would be needed to connect the string to the combiner, or combiners to each other. The resulting modular combiner design could support any number of strings through such assembly Additionally, such a device would ideally combine several common functions currently handled in separate electrical boxes or devices, including the electrical connections (junction box), circuit protection (combiner box), and optionally include means to identify faults and isolate a string from the array when desired (disconnect switch).
The invention pertains generally to electrical wiring, connectors, terminals and boxes, and particularly to those devices for use with solar photovoltaic modules and related electrical systems.
BACKGROUND
Solar photovoltaic modules (or panels) produce DC electrical power that is collected through wiring commonly attached to the back of the module. Multiple modules may be connected together to produce greater power. A plurality of modules connected in this fashion is commonly referred to as an array. To facilitate the rapid assembly of arrays, modules are commonly equipped with locking quick-connect electrical fittings. Among many such designs, Tyco and MC4 connectors are common.
Due to limitations, both physical and electrical, large arrays are often made up of several smaller arrays known as strings. Strings are then wired together electrically to produce the array.
The division into strings may be related to the physical layout of the array, for instance, when modules have to be separated to fit around an air conditioner unit on a roof.
In this case weatherproof enclosures known as junction boxes or chock boxes can be used to combine the wiring of the strings back together.
It is also common to use strings to keep the electrical wiring below prescribed voltage or current limits, or to limit short-circuit current flow. To protect against this possibility, the array is divided into strings and the strings are then isolated using circuit protection devices such as fuses or circuit breakers. These are commonly found in load centers, fuse boxes or combiner boxes; herein collectively referred to as combiners.
Common examples of junction boxes and combiners are not designed specifically for use in the solar industry. Generally, they are designed to connect using terminal block, wire nuts ("Marettes") or similar systems designed to connect to bare wire. Connecting a string to the combiner is thus a time consuming process, requires several tools, additional parts, and generally has to be carried out by a licensed electrician.
If the array requires more strings than a given combiner supports, multiple combiners are wired together. Known combiners lack any system for rapid interconnection, and labor-intensive wiring techniques like those for string connection are needed. Larger combiners with more terminals are also available, but often impractical due to their size, cost, and the need to run the wiring from the strings to the central location of the combiner.
Accordingly, what is desired is an improved junction/combiner system for the rapid assemblage of strings and arrays. Ideally, no tools would be needed to connect the string to the combiner, or combiners to each other. The resulting modular combiner design could support any number of strings through such assembly Additionally, such a device would ideally combine several common functions currently handled in separate electrical boxes or devices, including the electrical connections (junction box), circuit protection (combiner box), and optionally include means to identify faults and isolate a string from the array when desired (disconnect switch).
RELATED ART
It is in the known prior art to describe electrical combiner systems allowing the connection of arbitrary electrical equipment, as well as examples with built-in circuit protection devices. Generic devices like these are widespread in the solar industry. Bespoke systems equipped with common module connectors are also known, but not common. All of these exhibit the problems noted above, as they are not designed for rapid interconnection to form arrays.
Examples of combiner systems with customized construction intended for use in the renewable energy industry are also known. US Patent Application 10/612,873, Brown et al describes a wiring system and combiner box assembly for the rapid connection of several modules into a string.
However, the combiner system is a fixed size, and does not allow modular construction of an array of arbitrary size. Moreover, the combiner and string wiring is all of custom design, and does not allow for direct connection to known module wiring.
US Patent Application 11/379,728 by McClintock et al discusses a combiner box for use in the solar industry intended to aid with fault detection. Each combiner is designed to connect to multiple strings in order to identify which is at fault. It mentions improved installation time in the context of separately wiring monitoring consoles for the fault detection system. The terminals are all of conventional design intended for attachment to bare wire on the inside of the enclosure.
US Patent Application 12/657,069 by Fornage et all describes a connection system for individual solar modules to associated inverters. These are combined using a conventional load center.
US Patent Application 12/468,984 by Sok et al describes a solar array equipped with combiner boxes including DC-DC power converters. The combiners are themselves combined in parallel to form an array, using conventional combiners.
US Patent Application 12/942,750 by Schripsema describes a combiner system with built-in fault monitoring. Conventional wiring and terminals are used throughout.
US Patent Application 11/379,728 by McClintock et al describes a combiner system of conventional design with built-in fault monitoring and communications.
Conventional wiring and terminals are used throughout.
US Patent Application 12/288,956 by Lewis and Herzog describes a separate fault detection system that wired into the array in advance of conventional combiners.
US Patent 7987641 by Cinnamon describes mechanical details of a module mounting system.
Application US 12/796,466 by Cinnamon et al expands on US 7987641 with the description of a new electrical system intended for use with the described mounting system.
This includes a junction box with built-in quick-connect terminals. This is intended for use only with this mounting system, and lacks the ability to connect the junction boxes together, illustrating conventional conduit wiring.
US Patent Application 12/714,855 by Solon describes a system of wiring harnesses that include in-line fuses for string protection. They are shown with conventional combiners.
US Patent Application 12/582,367 by Luebke et all describes a system of advanced string protection devices, offering protection from arc faults in addition to more common faults like shorts.
Such systems are described as possibly being integrated in conventional combiners.
It is in the known prior art to describe electrical combiner systems allowing the connection of arbitrary electrical equipment, as well as examples with built-in circuit protection devices. Generic devices like these are widespread in the solar industry. Bespoke systems equipped with common module connectors are also known, but not common. All of these exhibit the problems noted above, as they are not designed for rapid interconnection to form arrays.
Examples of combiner systems with customized construction intended for use in the renewable energy industry are also known. US Patent Application 10/612,873, Brown et al describes a wiring system and combiner box assembly for the rapid connection of several modules into a string.
However, the combiner system is a fixed size, and does not allow modular construction of an array of arbitrary size. Moreover, the combiner and string wiring is all of custom design, and does not allow for direct connection to known module wiring.
US Patent Application 11/379,728 by McClintock et al discusses a combiner box for use in the solar industry intended to aid with fault detection. Each combiner is designed to connect to multiple strings in order to identify which is at fault. It mentions improved installation time in the context of separately wiring monitoring consoles for the fault detection system. The terminals are all of conventional design intended for attachment to bare wire on the inside of the enclosure.
US Patent Application 12/657,069 by Fornage et all describes a connection system for individual solar modules to associated inverters. These are combined using a conventional load center.
US Patent Application 12/468,984 by Sok et al describes a solar array equipped with combiner boxes including DC-DC power converters. The combiners are themselves combined in parallel to form an array, using conventional combiners.
US Patent Application 12/942,750 by Schripsema describes a combiner system with built-in fault monitoring. Conventional wiring and terminals are used throughout.
US Patent Application 11/379,728 by McClintock et al describes a combiner system of conventional design with built-in fault monitoring and communications.
Conventional wiring and terminals are used throughout.
US Patent Application 12/288,956 by Lewis and Herzog describes a separate fault detection system that wired into the array in advance of conventional combiners.
US Patent 7987641 by Cinnamon describes mechanical details of a module mounting system.
Application US 12/796,466 by Cinnamon et al expands on US 7987641 with the description of a new electrical system intended for use with the described mounting system.
This includes a junction box with built-in quick-connect terminals. This is intended for use only with this mounting system, and lacks the ability to connect the junction boxes together, illustrating conventional conduit wiring.
US Patent Application 12/714,855 by Solon describes a system of wiring harnesses that include in-line fuses for string protection. They are shown with conventional combiners.
US Patent Application 12/582,367 by Luebke et all describes a system of advanced string protection devices, offering protection from arc faults in addition to more common faults like shorts.
Such systems are described as possibly being integrated in conventional combiners.
SUMMARY OF THE INVENTION
The present invention describes an electrical combiner and junction box of unique construction intended to simplify the assembly of a plurality of solar modules into arrays.
The combiner includes, at a minimum, connectors for attachment of electrical equipment, and connectors for attachment between similar combiners to form a common electrical system.
According to the present invention, solar modules can be connected to the combiners directly, quickly, safely, and without tools. This is accomplished through the use of quick-connect terminals like those found on the solar modules.
According to the present invention, such combiners may also be connected together to form modular combiner systems supporting larger arrays of multiple strings of modules. This task may also be completed quickly, safely and without tools. This is accomplished with quick-connect terminals like those on the modules, or similar connectors more suitable for forming multi-conductor electrical connections.
According to the present invention, the resulting array may be easily connected to external electrical equipment.
According to the present invention, the safety of connection and disconnection of modules from strings may be improved, as connections are of the protected type, with no visibility of live conductors, and all terminals protected by insulated mechanical structures.
Embodiments of the present invention generally consist of combiner boxes with one or more sets of quick-connect terminals found on solar modules for connection to the string, and one or more quick-connect fittings for connecting combiners together into arrays.
Embodiments may also include circuit protection devices such as circuit breakers, fuses or disconnection switches.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a typical solar array consisting of one or more photovoltaic modules connected together using DC wiring to form a string, and multiple strings to form an array;
FIG. 1A is a block diagram of a system of one or more photovoltaic modules connected to individual inverters and AC wiring to form a string, and strings to form an array;
FIG. 2 is a schematic diagram of one possible embodiment of the present invention;
FIG. 3 is diagram of one possible embodiment of the present invention intended for junction box duties connected to generic electrical systems, which may include solar modules;
FIG. 3A is diagram of one possible embodiment of the present invention intended for combiner box duties and direct connection to solar modules with the MC4 style connector;
FIG. 3B is diagram of one possible embodiment of the present invention intended for combiner box duties and direct connection to inverters with the Enphase M190 style connector;
FIG. 3C is diagram of one possible embodiment of the present invention intended for combiner box duties that include an indicator lamp and disconnect switch;
FIG. 3D is diagram of one possible embodiment of the present invention intended to combine together the wiring of multiple combiners ("recombiner"), which includes a multi-pole disconnect switch and heavy-duty terminals for interconnection;
FIG. 3E is a diagram of a cabling assembly suitable for rapid interconnection of boxes as above;
FIG. 4 is a block diagram of a DC solar array similar to the one illustrated in Fig. 1, but implemented using the present invention;
FIG. 4A is a block diagram of an AC solar array similar to the one illustrated in Fig. IA, but implemented using the present invention;
FIG. 4B is a block diagram of a larger solar array constructed of several arrays as in Fig. 4 interconnected ("recombined")using the present invention;
FIG. 5 is a more detailed illustration of a sample assembled module string DETAILED DESCRIPTION OF THE INVENTION AND DRAWINGS
Solar arrays are constructed of a number of solar modules connected together electrically to form a single larger system, the array. FIG. 1 is a block diagram of a typical solar array consisting of one or more strings of one or more photovoltaic modules each. This diagram shows only one of a myriad of possible configurations, and those familiar in the art will recognize this diagram is in no way limiting.
The array 100 consists of a plurality of photovoltaic modules 101(1)...101(0) connected together using electrical wiring 102(1)...102(o). The array is further subdivided into a plurality of strings 104(1)...104(n) of modules connected using common wiring. To bring the wiring from both ends of the strings to a common point, strings may use extension cables, or "home runs", 103(1)...103(n).
Strings 104(1)...104(n) may be connected together through DC combiners 105 to form the array 100. Multiple combiners may be used, depending on the number of terminals in the combiner 105. In conventional systems, these combiners require manual assembly of the connections and normally support multiple strings in a single enclosure. Home runs may have to be lengthy in order to reach the location of a shared combiner, which may lead to energy losses in the wiring. Additionally, if multiple combiners 105 are used, inter-combiner wiring has to be installed using time consuming techniques.
The output of the array 100 is further isolated with optional load centers, disconnects and other safety systems 107, as mandated by local electrical and building codes. The output is then sent to the load 108. In "grid-tie" systems, the output of the array is run to an inverter as load 108.
Modern microelectronics has allowed the inverter to be reduced in size until it is suitable for mounting on an individual module. In such systems, the inverter is commonly referred to as a "micro-inverter", as typified by designs from Enphase Energy and Enecsys.
Unlike the example illustrated in Fig. 1 which uses DC power throughout, when using micro-inverters the electrical wiring carries AC power, which has certain advantages. As is the case in DC
arrays, wiring limitations often demand that the array be split into strings.
FIG. 1A is a block diagram of a typical solar array 200 consisting of a plurality of modules 201(1)...201(o) connected to individual inverters 202(1)...202(o). The inverters are connected to each other along the AC wiring bus 203(1)...203(n) to form strings 204(1)...204(n). Inverters 202(1)...202(o) are illustrated installed on the back of the modules, as is common, but not required.
Strings 204(1)...204(n) are connected through AC combiner or load center 205 along the AC
electrical bus 206 to form the array 200. If multiple combiners are needed, they are connected in parallel along AC bus 206. The output of the array along AC bus 206 is further isolated with optional load centers, disconnects and other safety systems 207, and then sent to an AC load 208.
The AC load 208 is commonly a power distribution panel or public electrical grid.
FIG. 2 is a schematic diagram of one possible embodiment of the present invention, combiner box 300. A module string 301 connects to the module terminals 302 and the associated grounding wire to grounding point 303. Upstream terminals 305 and downstream terminals 306 are connected to form an electrical bus 308. Module terminals 302 are connected in parallel to the electrical bus 308 through optional circuit breaker 310 and indicator lamp 309, as well as optional disconnect switch 311. The use of a single positive-indication circuit breaker 310 can fulfill the duties of 309, 310, and 311.
The following figures illustrate particular embodiments of the apparatus of the present patent in a variety of forms customized to allow rapid interconnection to a variety of devices commonly used in the solar industry. All of these combine the features of modularity of interconnection and rapid assembly of strings and arrays. These illustrations should not be considered limiting; any similar device featuring rapid connection and modular assembly is a part of the present invention.
FIG. 3 is a semi-diagrammatic view of one possible embodiment of the present invention 400 illustrating its basic mechanical layout.
Electrical terminals 401, the downstream terminal 401(D) and upstream terminal 401(U), may be connectors of any suitable quick-connect design. A wide variety of suitable connectors using cam-lock, bayonet and twist locking systems are suitable. The choice of connector will be subject to local electrical codes and common usage. This embodiment is illustrated with three-pin screw-lock terminals with an alignment "key".
The wiring to the electrical equipment being added to the bus formed along 401 is through the compression fitting 402. This embodiment would be suitable for connection to arbitrary electrical equipment, not just modules, but other equipment such as monitoring devices.
Optional indicator LED 403 is connected to the internal circuit breaker or fuse holder in order to indicate a tripped condition. In the case of push-button or other visible breakers, lamp 403 is redundant. Alternately, circuit breaker/fuse holder may include a built-in indicator lamp, in which case an optically clear window in the proper location may be used to replace lamp 403.
Optional flanges 404 are used to protect terminals 401 and compression fitting 402 from mechanical damage, as well as providing attachment points for electrical conduit fittings. These are illustrated being shorter than those normally found on PVC T-junction boxes to allow easy access to the fittings and terminals These are illustrated as threaded fittings suitable for 2-inch PVC conduit, large enough to pass common fittings used in the industry. As all of the fittings used in this embodiment are suitable for unprotected outdoor use, flanges 404 are provided only for convenience.
FIG. 3A is a partial diagram showing the basic embodiment 400 shown in FIG. 4 customized for use with MC4 DC connectors. This embodiment replaces the compression fitting 402 with male 405(M) and female 405(F) MC4 connectors and uses C-style grounding lug 406 for chassis grounding. This embodiment is also suitable for use with Tyco or other standard connectors in place of MC4 connectors. As panel-mount connectors are generally fragile, an alternate embodiment would retain the compression fitting 402 and use short lengths of wire to attach the MC4 connectors, as shown in the inset in the lower right.
Optional disconnect switch 407 is located on the back of the box. Mounting this on the lid is possible, but would make maintenance access more difficult. If the fuse or circuit breaker can be reset from the outside of this case, switch 407 and LED 404 can be easily relocated to the box top.
FIG. 3B is a partial diagram showing the basic embodiment 400 shown in FIG. 3 customized for use with inverters embedded in the strings (micro-inverters). This embodiment replaces the upstream and downstream terminals 401 with multi-pin connectors 408 suitable for use with split-phase or three-phase power, 408(U) and 408(D). In this embodiment, compression fitting 402 has been replaced with Enphase Ml 90 female connector input terminal 409. These terminals are robust, suitable for direct mounting as in this embodiment. Terminal 409 can be replaced by any similar connector, such as those used on Enecsys or SMA micro-inverters.
The electrical limitations that require arrays to be broken into strings may also apply to the wiring used in the electrical bus connecting the strings together. In these instances, the electrical bus is further divided, isolated using circuit protection systems in larger combiners, and then combined into an array using heavier gauge electrical cabling between these combiners.
Often the electrical cabling is internal to a larger combiner. In these instances combiners are sometimes referred to as "recombiners".
FIG. 3D shows another possible embodiment of the current invention 400 modified for recombiner duties, offering the same advantages of quick assembly and modular construction. It differs only in mechanical construction and the size and power rating of the electrical components.
Combiner 400 includes one or more bus terminals 410(1)...410(n) of type similar to 401 or 408, built-in multi-pole disconnect switch 411 and optional indicator lamps 412(1)...412(n).
Interconnection between examples of this embodiment are provided by the heavy-duty bus terminals 414(U) and 414(D), illustrated in this embodiment using individual cables for each phase of power and connecting using Cam-Lock connectors widely used in industry.
The following are examples of installations of solar arrays in accordance with the method of the present invention. Anyone of ordinary skill in the art will recognize that there could be any number of modules, strings and electrical arrangements of the present invention, and these diagrams should be in no way considered limiting.
FIG. 4 is a block diagram of an array similar to Fig. I constructed to produce array 500 using the present invention. Strings 104(1)...104(m) are individually connected to DC combiners 501(1)...501(o) of the type illustrated in Fig. 3A. Combiners 501(1)...501(m) are interconnected using quick-connect bus cabling to form DC bus 502. The free end of bus 502 is closed off with terminator cap 503, while the load end is connected with home run cable 504 along the same bus.
FIG. 4.4 is a block diagram of an array similar to Fig. IA constructed to produce array 500 using the present invention. Strings 204(1)...204(m) are individually connected to AC combiners 505(1)...505(o) of the type illustrated in Fig. 3B. Combiners 505(1)...505(m) are interconnected using quick-connect bus cabling to form AC bus 506. The free end of bus 506 is closed off with terminator cap 507, while the load end is connected with home run cable 508 along the same bus.
FIG. 4B is a block diagram of a large array constructed of multiple examples of arrays 500(1) ...500(n) as in FIG. 4, interconnected with array-connection combiners 509 as illustrated in FIG.
3D. Arrays are connected to combiners 509(1)...509(n) through bus cables 510(1)...510(n) and to each other using bus cables 511(1)...511(n), the last of which is connected to terminating safety devices 512 and then to the load 513.
The following are illustrations of possible array layouts assembled using the present invention. In general, assembly will progress with the installation of the modules onto a mechanical support structure commonly referred to as "racking". If a micro-inverter or power optimizer device will be used, this is commonly installed at the same location as the modules. The modules, or their inverters, are then wired together using provided cabling. Grounding systems are also installed, normally using separate wiring attached to grounding lugs screwed into the frames of the modules and racking.
Further assembly using the present invention would then progress by connecting the free ends of the module cabling to the quick-connect fittings on the combiner. Combiners are then interconnected to each other using bus cabling attached to the associated terminals. The first combiner within any section of the array, the combiner furthest from the load, will have an open interconnection terminal that is closed off with a cap. The last combiner within any section of the array, the combiner closest to the load, will then be connected to a "home run" cable for connection to arbitrary electrical equipment, or another bus cable if it is to be connected into a larger array-of-arrays.
FIG. 5 illustrates the construction of an array 500 using the present invention. Strings 104(1) ...104(m) are individually connected to DC combiners 501(1)...501(o) of the type illustrated in Fig. 3A. Combiners 501(1)...501(o) are interconnected using quick-connect bus cabling to form DC bus 502. The free end of bus 502 is closed off with terminator cap 503, the load-side end of DC bus is connected to arbitrary safety systems, and then to the load.
Background and terminology Solar photovoltaics, or simply "PV", is the field of directly converting sunlight into electrical power. This typically occurs in the "solar cell", a semiconductor device with wiring for power collection.
Individual solar cells produce little power, so in practice many cells are connected together to form a "solar panel", or "module". Modules encapsulate the cells, offering mechanical protection from the elements. The cells are wired to each other in the module and exit into a "junction box" or "combiner box" on the back of the module.
As it is that a single cell is generally not useful by itself, modules are generally too low power to be used alone. Where cells are combined into modules, multiple modules are typically combined into larger systems known as "solar arrays", or simply "arrays".
To facilitate easy interconnection of the modules into arrays, wires lead from the junction boxes on the panels to quick-connecting electrical terminals at the end of the wires. Simply snapping these terminals together can interconnect modules into an array. For legal reasons, these terminals are commonly mechanical-locking designs that require special tools to separate.
It should be noted that the terms "panel", "module", "cell" and "array" are being used in their modern sense. There are many patents that refer to the electrical interconnection of solar arrays, but are in fact referring to solar cells. See as an example. Similarly, the term "junction box" likely refers to the connections on the back of the panel, not to external connectors for module strings. See US
12/988,411 as an example.
The problem The wiring used on the modules cannot handle an arbitrary amount of power.
Most common module designs use 10 gauge copper wiring, which limits any single run to between 15 and 20 panels before the combined power reaches the limits of the cabling. Connecting more modules together risks an over-current situation.
In order to build larger arrays, the array is broken down into a series of "strings"
of 10 to 15 panels. Strings are then connected to each other to form the array.
Strings must be isolated from the others in order to prevent current from one string flowing into another and causing an over-current condition. This is normally accomplished with one of a number of common electrical devices, known as load centers, junction boxes or combiners. These should not be confused with the junction boxes found on the panels themselves.
As these devices are not designed specifically for the solar industry, they lack the quick-connect fittings used on the modules. To connect a string to one of them, the existing connectors must either be cut off, or a second set of connectors with "free ends" has to be added. In either case the bare wires have to be connected on the inside of the isolation device. For legal reasons, handing bare wire is normally only allowed by licensed electricians.
Then if more than one such box has been used, which is the common case, the boxes must be wired to each other using similar methods. In our experience, this wiring represented a significant amount of the total time needed to install the array.
Additionally, this was typically very costly in terms of parts and labor.
A system that allows rapid, safe and inexpensive interconnection of strings into arrays is an obvious need in the industry Yet an extensive product search turns up nothing of the sort. The only "solution" on offer were large combiner boxes with many terminals inside, so that all the wiring could be done at a single spot.
The downside of this approach is that all of the string wiring must be run to the location of the box, and both the box and such cabling is very expensive.
In any event, all known junction and combiner boxes on offer -large and small-use generic electrical terminals for bare-wire connection. These are generally products used in other markets being re-purposed without any modification.
The field of this invention The invention proposed in this application is a solution to the problem of assembling modules into strings and strings into arrays, and doing so quickly, without the need for an electrician, and in most cases without the need for tools.
It does this primarily through the use of quick-connect electrical terminals connecting both the modules, and just as importantly, the combiners. Systems for rapid interconnection of combiners are not known in the state of the art, or in industry The invention also combines together several formerly separate devices into one box. This has the advantage of reducing the parts count of the system as a whole, and further easing installation.
The combiner also incorporates all needed circuit protection systems, and may also include additional electrical hardware used in common installations, like disconnection systems and fault monitoring.
The combiners are designed to be as small as possible, which allows their mounting on the array itself. This eliminates any extra cabling that might otherwise be needed to connect the strings to a remote combiner box.
The simple act of assembling the system completes many separate stages of installation and wiring otherwise required.
Preliminary search Examining Canadian, US and WIPO Gold patent databases turns up a number of patents and applications describing electrical connections in the PV field, the majority of which can be separated into several broad categories:
1)Descriptions of the wiring of cells into a module 2)Descriptions of the junction box on the back of the module and the wires connecting to them 3)Descriptions of the connectors at the end of the wires that connect to adjacent modules None of these categories have applicability to the present invention. However, there are two additional categories that are closer in concept:
4)Descriptions of panel mounting systems that sometimes also describe the electrical interconnections between panels 5)Combiner boxes intended to help isolate electrical faults Only patents that fall into category 4 or 5 have any bearing on the present patent application, and an extensive search of these fails to turn up any concepts specifically dedicated to the problem as outlined above.
Searching the CIPO online database for Canadian patents including "solar panel"
returns 122 patents, the vast majority of which refer to the panel as part of some other assembly, like roadway lighting, or describe solar heating systems. Of those that remain, only the following Canadian patents discuss solar PV arrays and their interconnection:
2574659, 2475524, 2472548, 2701864 2703324, 2695754, 2542672, 2542672 None of these, however, discuss electrical issues except in passing. 2542672 implicitly includes electrical interconnection of modules, but in a way that can only be used with the unique solar panel system described within. None of these patents even mentions the problem the present invention is attempting to solve.
Examining the US patent database turns up many more relevant hits on concepts that fall into category 4 and 5.
A few patents describe combiner systems and are clearly similar to the present invention. These include:
10/612,873 US Patent Application 10/612,873, Brown et al describes a wiring system and combiner box assembly for the rapid connection of several modules into a string. The Background section specifically talks about the need for an electrician to handle the wiring of the system. This invention does address at least some of the problems considered in the present invention. However, this system uses custom connectors throughout the system, and is combined in a single combiner box, whereas the present invention uses standardized connectors throughout, and allows modular construction of the combiners from individual building blocks.
12/942,750 US Patent Application 12/942,750 by Schripsema describes a combiner system with monitoring, mechanically constructed using conventional screw-down terminal blocks without quick-connectors. This invention inherits the installation problems of conventional systems.
11/379,728 US Patent Application 11/379,728 by McClintock et al discusses a combiner box for use in the solar industry intended to aid with fault detection. It refers to several previous US Patents that are also concerned with fault detection. Although it mentions improved installation time, it does so in the context of eliminating the need to separately wire monitoring consoles. Moreover, each combiner is designed to connect to multiple strings in order to identify which is at fault.
12/468,984 US Patent Application 12/468,984 by Sok et al describes a solar array equipped with combiner boxes including DC-DC power converters. The combiners are themselves combined in parallel to form an array.
12/657,069 US Patent Application 12/657,069 by Fornage et all describes a connection system for individual solar modules. These are combined in a generic load center, labeled 108 in the associated figures.
12/961,249 US Patent Application 12/961,249 by Brescia describes a systems for integrating modules into the building structure Another small group of patents discusses custom combiner systems as part of a custom panel or module installation system. These include:
12/796,466 US 7987641 (also known as CA 2702663) is concerned primarily with the mechanical details of the new mounting system. In order to incorporate the electrical wiring, the patent proposes cutting channels into the frame of the panels, as shown in Figure 2A. This presents problems in terms of structural integrity Application US 12/796,466 expands on US 7987641, induding a new wiring system that addresses the problems of the earlier patent. This design moves the connectors from "free" wires on the back of the panel to a fixed location on the side of the panel frame. This way simply placing two panels next to each other allows their interconnection, and the electrical wiring is better protected.
Of interest, Figure 2A of US 12/796,466 illustrates an array build using the patent's framing system. This includes a "combiner junction box" labeled 121".
This combiner connects to the panels using MC4 connectors. The use of the same type of connector as found on the panel is a key part of the present invention. Figure illustrates two strings being combined in an unlabeled combiner box, but the application test does not mention this device nor does it appear to be part of the claims.
A larger number of patents discuss combiners, but do so as part of a standard system. Some even refer to existing combiner systems using conventional terminals.
12/714,855 US Patent Application 12/714,855 by Solon describes a system of wiring harnesses that include in-line fuses for string protection. The patent shows these being used before connection to a conventional combiner.
12/288,956 US Patent Application 12/288,956 by Lewis and Herzog is likewise concerned with fault detection and utilizes a monitor system that is wired into the array in advance of the combiners. It does not cover the combiners themselves.
12/582,367 US Patent Application 12/582,367 by Luebke et all describes a system of string protection devices, some of which are placed inside combiner boxes. The patent is primarily concerned with the prevention of arc faults in addition to more common faults like shorts.
12/637,873 US Patent Application 12/637,873 by Hastings et al describes a system similar to 12/582,367, using fault detection systems optionally included in the combiner.
The patent appears very similar to 12/582,367, including several Figures in common.
12/088,978 US Patent Application 12/088,978 by Thomspon et at describes a system of srring-level monitoring systems known as StringPAK. These are connected together into groups of up to 10 panels using combiner boxes. The application does not describe the combiner although it suggests the PCB10, which is a conventional metal NEMA3R combiner with conventional terminals.
12/562,933 US Patent Application 12/562,933 by Hadar et all describes a panel-level monitoring system connected to a conventional combiner.
12/487,564 US Patent Application 12/487,564 by Gervorkian likewise describes a system including panel-level monitoring that are built into arrays using conventional combiners.
10/679,814 Like CA 2542672, 10/679,814 describes a custom solar panel that includes electrical connectors as part of its structure. In this case the panels are flat sheets that connect together at the edges to form arrays. As in earlier examples, no consideration of string isolation is mentioned.
11/465,787 Another example of a custom panel/connector system is 11/465,787, which uses cabling extended from the edge of a frameless panel that are connected together using splicing units. As in earlier examples, no consideration of string isolation is mentioned.
Figure 12 and Figure 13 appear to show a combiner, but the associated text in paragraph [0051] describes item 204 as an inverter.
11/777,397 US Patent Application 11/777,397 covers a roofing system with solar panels built-in, which are combined with a custom combiner into strings and arrays.
In spite of this extensive search, it appears that only a single patent even attempts to address the same problem, 10/612,873. However, Brown's invention retains the idea of a single larger combiner, lacking the modularity of the current invention.
Additionally, it uses non-standard connectors throughout, which essentially eliminates its utility - which may be why there appears to have been zero adoption of this concept.
The rest of the patents discuss combiners and similar technologies only in passing.
as part of other technologies. None of these appear to even consider the wiring issues the present invention addresses. Only one, 12/796,466, even shows an electrical box like those used in the industry, and does so only because their design demands a custom connection system due to non-standard connector use.
The present invention describes an electrical combiner and junction box of unique construction intended to simplify the assembly of a plurality of solar modules into arrays.
The combiner includes, at a minimum, connectors for attachment of electrical equipment, and connectors for attachment between similar combiners to form a common electrical system.
According to the present invention, solar modules can be connected to the combiners directly, quickly, safely, and without tools. This is accomplished through the use of quick-connect terminals like those found on the solar modules.
According to the present invention, such combiners may also be connected together to form modular combiner systems supporting larger arrays of multiple strings of modules. This task may also be completed quickly, safely and without tools. This is accomplished with quick-connect terminals like those on the modules, or similar connectors more suitable for forming multi-conductor electrical connections.
According to the present invention, the resulting array may be easily connected to external electrical equipment.
According to the present invention, the safety of connection and disconnection of modules from strings may be improved, as connections are of the protected type, with no visibility of live conductors, and all terminals protected by insulated mechanical structures.
Embodiments of the present invention generally consist of combiner boxes with one or more sets of quick-connect terminals found on solar modules for connection to the string, and one or more quick-connect fittings for connecting combiners together into arrays.
Embodiments may also include circuit protection devices such as circuit breakers, fuses or disconnection switches.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a typical solar array consisting of one or more photovoltaic modules connected together using DC wiring to form a string, and multiple strings to form an array;
FIG. 1A is a block diagram of a system of one or more photovoltaic modules connected to individual inverters and AC wiring to form a string, and strings to form an array;
FIG. 2 is a schematic diagram of one possible embodiment of the present invention;
FIG. 3 is diagram of one possible embodiment of the present invention intended for junction box duties connected to generic electrical systems, which may include solar modules;
FIG. 3A is diagram of one possible embodiment of the present invention intended for combiner box duties and direct connection to solar modules with the MC4 style connector;
FIG. 3B is diagram of one possible embodiment of the present invention intended for combiner box duties and direct connection to inverters with the Enphase M190 style connector;
FIG. 3C is diagram of one possible embodiment of the present invention intended for combiner box duties that include an indicator lamp and disconnect switch;
FIG. 3D is diagram of one possible embodiment of the present invention intended to combine together the wiring of multiple combiners ("recombiner"), which includes a multi-pole disconnect switch and heavy-duty terminals for interconnection;
FIG. 3E is a diagram of a cabling assembly suitable for rapid interconnection of boxes as above;
FIG. 4 is a block diagram of a DC solar array similar to the one illustrated in Fig. 1, but implemented using the present invention;
FIG. 4A is a block diagram of an AC solar array similar to the one illustrated in Fig. IA, but implemented using the present invention;
FIG. 4B is a block diagram of a larger solar array constructed of several arrays as in Fig. 4 interconnected ("recombined")using the present invention;
FIG. 5 is a more detailed illustration of a sample assembled module string DETAILED DESCRIPTION OF THE INVENTION AND DRAWINGS
Solar arrays are constructed of a number of solar modules connected together electrically to form a single larger system, the array. FIG. 1 is a block diagram of a typical solar array consisting of one or more strings of one or more photovoltaic modules each. This diagram shows only one of a myriad of possible configurations, and those familiar in the art will recognize this diagram is in no way limiting.
The array 100 consists of a plurality of photovoltaic modules 101(1)...101(0) connected together using electrical wiring 102(1)...102(o). The array is further subdivided into a plurality of strings 104(1)...104(n) of modules connected using common wiring. To bring the wiring from both ends of the strings to a common point, strings may use extension cables, or "home runs", 103(1)...103(n).
Strings 104(1)...104(n) may be connected together through DC combiners 105 to form the array 100. Multiple combiners may be used, depending on the number of terminals in the combiner 105. In conventional systems, these combiners require manual assembly of the connections and normally support multiple strings in a single enclosure. Home runs may have to be lengthy in order to reach the location of a shared combiner, which may lead to energy losses in the wiring. Additionally, if multiple combiners 105 are used, inter-combiner wiring has to be installed using time consuming techniques.
The output of the array 100 is further isolated with optional load centers, disconnects and other safety systems 107, as mandated by local electrical and building codes. The output is then sent to the load 108. In "grid-tie" systems, the output of the array is run to an inverter as load 108.
Modern microelectronics has allowed the inverter to be reduced in size until it is suitable for mounting on an individual module. In such systems, the inverter is commonly referred to as a "micro-inverter", as typified by designs from Enphase Energy and Enecsys.
Unlike the example illustrated in Fig. 1 which uses DC power throughout, when using micro-inverters the electrical wiring carries AC power, which has certain advantages. As is the case in DC
arrays, wiring limitations often demand that the array be split into strings.
FIG. 1A is a block diagram of a typical solar array 200 consisting of a plurality of modules 201(1)...201(o) connected to individual inverters 202(1)...202(o). The inverters are connected to each other along the AC wiring bus 203(1)...203(n) to form strings 204(1)...204(n). Inverters 202(1)...202(o) are illustrated installed on the back of the modules, as is common, but not required.
Strings 204(1)...204(n) are connected through AC combiner or load center 205 along the AC
electrical bus 206 to form the array 200. If multiple combiners are needed, they are connected in parallel along AC bus 206. The output of the array along AC bus 206 is further isolated with optional load centers, disconnects and other safety systems 207, and then sent to an AC load 208.
The AC load 208 is commonly a power distribution panel or public electrical grid.
FIG. 2 is a schematic diagram of one possible embodiment of the present invention, combiner box 300. A module string 301 connects to the module terminals 302 and the associated grounding wire to grounding point 303. Upstream terminals 305 and downstream terminals 306 are connected to form an electrical bus 308. Module terminals 302 are connected in parallel to the electrical bus 308 through optional circuit breaker 310 and indicator lamp 309, as well as optional disconnect switch 311. The use of a single positive-indication circuit breaker 310 can fulfill the duties of 309, 310, and 311.
The following figures illustrate particular embodiments of the apparatus of the present patent in a variety of forms customized to allow rapid interconnection to a variety of devices commonly used in the solar industry. All of these combine the features of modularity of interconnection and rapid assembly of strings and arrays. These illustrations should not be considered limiting; any similar device featuring rapid connection and modular assembly is a part of the present invention.
FIG. 3 is a semi-diagrammatic view of one possible embodiment of the present invention 400 illustrating its basic mechanical layout.
Electrical terminals 401, the downstream terminal 401(D) and upstream terminal 401(U), may be connectors of any suitable quick-connect design. A wide variety of suitable connectors using cam-lock, bayonet and twist locking systems are suitable. The choice of connector will be subject to local electrical codes and common usage. This embodiment is illustrated with three-pin screw-lock terminals with an alignment "key".
The wiring to the electrical equipment being added to the bus formed along 401 is through the compression fitting 402. This embodiment would be suitable for connection to arbitrary electrical equipment, not just modules, but other equipment such as monitoring devices.
Optional indicator LED 403 is connected to the internal circuit breaker or fuse holder in order to indicate a tripped condition. In the case of push-button or other visible breakers, lamp 403 is redundant. Alternately, circuit breaker/fuse holder may include a built-in indicator lamp, in which case an optically clear window in the proper location may be used to replace lamp 403.
Optional flanges 404 are used to protect terminals 401 and compression fitting 402 from mechanical damage, as well as providing attachment points for electrical conduit fittings. These are illustrated being shorter than those normally found on PVC T-junction boxes to allow easy access to the fittings and terminals These are illustrated as threaded fittings suitable for 2-inch PVC conduit, large enough to pass common fittings used in the industry. As all of the fittings used in this embodiment are suitable for unprotected outdoor use, flanges 404 are provided only for convenience.
FIG. 3A is a partial diagram showing the basic embodiment 400 shown in FIG. 4 customized for use with MC4 DC connectors. This embodiment replaces the compression fitting 402 with male 405(M) and female 405(F) MC4 connectors and uses C-style grounding lug 406 for chassis grounding. This embodiment is also suitable for use with Tyco or other standard connectors in place of MC4 connectors. As panel-mount connectors are generally fragile, an alternate embodiment would retain the compression fitting 402 and use short lengths of wire to attach the MC4 connectors, as shown in the inset in the lower right.
Optional disconnect switch 407 is located on the back of the box. Mounting this on the lid is possible, but would make maintenance access more difficult. If the fuse or circuit breaker can be reset from the outside of this case, switch 407 and LED 404 can be easily relocated to the box top.
FIG. 3B is a partial diagram showing the basic embodiment 400 shown in FIG. 3 customized for use with inverters embedded in the strings (micro-inverters). This embodiment replaces the upstream and downstream terminals 401 with multi-pin connectors 408 suitable for use with split-phase or three-phase power, 408(U) and 408(D). In this embodiment, compression fitting 402 has been replaced with Enphase Ml 90 female connector input terminal 409. These terminals are robust, suitable for direct mounting as in this embodiment. Terminal 409 can be replaced by any similar connector, such as those used on Enecsys or SMA micro-inverters.
The electrical limitations that require arrays to be broken into strings may also apply to the wiring used in the electrical bus connecting the strings together. In these instances, the electrical bus is further divided, isolated using circuit protection systems in larger combiners, and then combined into an array using heavier gauge electrical cabling between these combiners.
Often the electrical cabling is internal to a larger combiner. In these instances combiners are sometimes referred to as "recombiners".
FIG. 3D shows another possible embodiment of the current invention 400 modified for recombiner duties, offering the same advantages of quick assembly and modular construction. It differs only in mechanical construction and the size and power rating of the electrical components.
Combiner 400 includes one or more bus terminals 410(1)...410(n) of type similar to 401 or 408, built-in multi-pole disconnect switch 411 and optional indicator lamps 412(1)...412(n).
Interconnection between examples of this embodiment are provided by the heavy-duty bus terminals 414(U) and 414(D), illustrated in this embodiment using individual cables for each phase of power and connecting using Cam-Lock connectors widely used in industry.
The following are examples of installations of solar arrays in accordance with the method of the present invention. Anyone of ordinary skill in the art will recognize that there could be any number of modules, strings and electrical arrangements of the present invention, and these diagrams should be in no way considered limiting.
FIG. 4 is a block diagram of an array similar to Fig. I constructed to produce array 500 using the present invention. Strings 104(1)...104(m) are individually connected to DC combiners 501(1)...501(o) of the type illustrated in Fig. 3A. Combiners 501(1)...501(m) are interconnected using quick-connect bus cabling to form DC bus 502. The free end of bus 502 is closed off with terminator cap 503, while the load end is connected with home run cable 504 along the same bus.
FIG. 4.4 is a block diagram of an array similar to Fig. IA constructed to produce array 500 using the present invention. Strings 204(1)...204(m) are individually connected to AC combiners 505(1)...505(o) of the type illustrated in Fig. 3B. Combiners 505(1)...505(m) are interconnected using quick-connect bus cabling to form AC bus 506. The free end of bus 506 is closed off with terminator cap 507, while the load end is connected with home run cable 508 along the same bus.
FIG. 4B is a block diagram of a large array constructed of multiple examples of arrays 500(1) ...500(n) as in FIG. 4, interconnected with array-connection combiners 509 as illustrated in FIG.
3D. Arrays are connected to combiners 509(1)...509(n) through bus cables 510(1)...510(n) and to each other using bus cables 511(1)...511(n), the last of which is connected to terminating safety devices 512 and then to the load 513.
The following are illustrations of possible array layouts assembled using the present invention. In general, assembly will progress with the installation of the modules onto a mechanical support structure commonly referred to as "racking". If a micro-inverter or power optimizer device will be used, this is commonly installed at the same location as the modules. The modules, or their inverters, are then wired together using provided cabling. Grounding systems are also installed, normally using separate wiring attached to grounding lugs screwed into the frames of the modules and racking.
Further assembly using the present invention would then progress by connecting the free ends of the module cabling to the quick-connect fittings on the combiner. Combiners are then interconnected to each other using bus cabling attached to the associated terminals. The first combiner within any section of the array, the combiner furthest from the load, will have an open interconnection terminal that is closed off with a cap. The last combiner within any section of the array, the combiner closest to the load, will then be connected to a "home run" cable for connection to arbitrary electrical equipment, or another bus cable if it is to be connected into a larger array-of-arrays.
FIG. 5 illustrates the construction of an array 500 using the present invention. Strings 104(1) ...104(m) are individually connected to DC combiners 501(1)...501(o) of the type illustrated in Fig. 3A. Combiners 501(1)...501(o) are interconnected using quick-connect bus cabling to form DC bus 502. The free end of bus 502 is closed off with terminator cap 503, the load-side end of DC bus is connected to arbitrary safety systems, and then to the load.
Background and terminology Solar photovoltaics, or simply "PV", is the field of directly converting sunlight into electrical power. This typically occurs in the "solar cell", a semiconductor device with wiring for power collection.
Individual solar cells produce little power, so in practice many cells are connected together to form a "solar panel", or "module". Modules encapsulate the cells, offering mechanical protection from the elements. The cells are wired to each other in the module and exit into a "junction box" or "combiner box" on the back of the module.
As it is that a single cell is generally not useful by itself, modules are generally too low power to be used alone. Where cells are combined into modules, multiple modules are typically combined into larger systems known as "solar arrays", or simply "arrays".
To facilitate easy interconnection of the modules into arrays, wires lead from the junction boxes on the panels to quick-connecting electrical terminals at the end of the wires. Simply snapping these terminals together can interconnect modules into an array. For legal reasons, these terminals are commonly mechanical-locking designs that require special tools to separate.
It should be noted that the terms "panel", "module", "cell" and "array" are being used in their modern sense. There are many patents that refer to the electrical interconnection of solar arrays, but are in fact referring to solar cells. See as an example. Similarly, the term "junction box" likely refers to the connections on the back of the panel, not to external connectors for module strings. See US
12/988,411 as an example.
The problem The wiring used on the modules cannot handle an arbitrary amount of power.
Most common module designs use 10 gauge copper wiring, which limits any single run to between 15 and 20 panels before the combined power reaches the limits of the cabling. Connecting more modules together risks an over-current situation.
In order to build larger arrays, the array is broken down into a series of "strings"
of 10 to 15 panels. Strings are then connected to each other to form the array.
Strings must be isolated from the others in order to prevent current from one string flowing into another and causing an over-current condition. This is normally accomplished with one of a number of common electrical devices, known as load centers, junction boxes or combiners. These should not be confused with the junction boxes found on the panels themselves.
As these devices are not designed specifically for the solar industry, they lack the quick-connect fittings used on the modules. To connect a string to one of them, the existing connectors must either be cut off, or a second set of connectors with "free ends" has to be added. In either case the bare wires have to be connected on the inside of the isolation device. For legal reasons, handing bare wire is normally only allowed by licensed electricians.
Then if more than one such box has been used, which is the common case, the boxes must be wired to each other using similar methods. In our experience, this wiring represented a significant amount of the total time needed to install the array.
Additionally, this was typically very costly in terms of parts and labor.
A system that allows rapid, safe and inexpensive interconnection of strings into arrays is an obvious need in the industry Yet an extensive product search turns up nothing of the sort. The only "solution" on offer were large combiner boxes with many terminals inside, so that all the wiring could be done at a single spot.
The downside of this approach is that all of the string wiring must be run to the location of the box, and both the box and such cabling is very expensive.
In any event, all known junction and combiner boxes on offer -large and small-use generic electrical terminals for bare-wire connection. These are generally products used in other markets being re-purposed without any modification.
The field of this invention The invention proposed in this application is a solution to the problem of assembling modules into strings and strings into arrays, and doing so quickly, without the need for an electrician, and in most cases without the need for tools.
It does this primarily through the use of quick-connect electrical terminals connecting both the modules, and just as importantly, the combiners. Systems for rapid interconnection of combiners are not known in the state of the art, or in industry The invention also combines together several formerly separate devices into one box. This has the advantage of reducing the parts count of the system as a whole, and further easing installation.
The combiner also incorporates all needed circuit protection systems, and may also include additional electrical hardware used in common installations, like disconnection systems and fault monitoring.
The combiners are designed to be as small as possible, which allows their mounting on the array itself. This eliminates any extra cabling that might otherwise be needed to connect the strings to a remote combiner box.
The simple act of assembling the system completes many separate stages of installation and wiring otherwise required.
Preliminary search Examining Canadian, US and WIPO Gold patent databases turns up a number of patents and applications describing electrical connections in the PV field, the majority of which can be separated into several broad categories:
1)Descriptions of the wiring of cells into a module 2)Descriptions of the junction box on the back of the module and the wires connecting to them 3)Descriptions of the connectors at the end of the wires that connect to adjacent modules None of these categories have applicability to the present invention. However, there are two additional categories that are closer in concept:
4)Descriptions of panel mounting systems that sometimes also describe the electrical interconnections between panels 5)Combiner boxes intended to help isolate electrical faults Only patents that fall into category 4 or 5 have any bearing on the present patent application, and an extensive search of these fails to turn up any concepts specifically dedicated to the problem as outlined above.
Searching the CIPO online database for Canadian patents including "solar panel"
returns 122 patents, the vast majority of which refer to the panel as part of some other assembly, like roadway lighting, or describe solar heating systems. Of those that remain, only the following Canadian patents discuss solar PV arrays and their interconnection:
2574659, 2475524, 2472548, 2701864 2703324, 2695754, 2542672, 2542672 None of these, however, discuss electrical issues except in passing. 2542672 implicitly includes electrical interconnection of modules, but in a way that can only be used with the unique solar panel system described within. None of these patents even mentions the problem the present invention is attempting to solve.
Examining the US patent database turns up many more relevant hits on concepts that fall into category 4 and 5.
A few patents describe combiner systems and are clearly similar to the present invention. These include:
10/612,873 US Patent Application 10/612,873, Brown et al describes a wiring system and combiner box assembly for the rapid connection of several modules into a string. The Background section specifically talks about the need for an electrician to handle the wiring of the system. This invention does address at least some of the problems considered in the present invention. However, this system uses custom connectors throughout the system, and is combined in a single combiner box, whereas the present invention uses standardized connectors throughout, and allows modular construction of the combiners from individual building blocks.
12/942,750 US Patent Application 12/942,750 by Schripsema describes a combiner system with monitoring, mechanically constructed using conventional screw-down terminal blocks without quick-connectors. This invention inherits the installation problems of conventional systems.
11/379,728 US Patent Application 11/379,728 by McClintock et al discusses a combiner box for use in the solar industry intended to aid with fault detection. It refers to several previous US Patents that are also concerned with fault detection. Although it mentions improved installation time, it does so in the context of eliminating the need to separately wire monitoring consoles. Moreover, each combiner is designed to connect to multiple strings in order to identify which is at fault.
12/468,984 US Patent Application 12/468,984 by Sok et al describes a solar array equipped with combiner boxes including DC-DC power converters. The combiners are themselves combined in parallel to form an array.
12/657,069 US Patent Application 12/657,069 by Fornage et all describes a connection system for individual solar modules. These are combined in a generic load center, labeled 108 in the associated figures.
12/961,249 US Patent Application 12/961,249 by Brescia describes a systems for integrating modules into the building structure Another small group of patents discusses custom combiner systems as part of a custom panel or module installation system. These include:
12/796,466 US 7987641 (also known as CA 2702663) is concerned primarily with the mechanical details of the new mounting system. In order to incorporate the electrical wiring, the patent proposes cutting channels into the frame of the panels, as shown in Figure 2A. This presents problems in terms of structural integrity Application US 12/796,466 expands on US 7987641, induding a new wiring system that addresses the problems of the earlier patent. This design moves the connectors from "free" wires on the back of the panel to a fixed location on the side of the panel frame. This way simply placing two panels next to each other allows their interconnection, and the electrical wiring is better protected.
Of interest, Figure 2A of US 12/796,466 illustrates an array build using the patent's framing system. This includes a "combiner junction box" labeled 121".
This combiner connects to the panels using MC4 connectors. The use of the same type of connector as found on the panel is a key part of the present invention. Figure illustrates two strings being combined in an unlabeled combiner box, but the application test does not mention this device nor does it appear to be part of the claims.
A larger number of patents discuss combiners, but do so as part of a standard system. Some even refer to existing combiner systems using conventional terminals.
12/714,855 US Patent Application 12/714,855 by Solon describes a system of wiring harnesses that include in-line fuses for string protection. The patent shows these being used before connection to a conventional combiner.
12/288,956 US Patent Application 12/288,956 by Lewis and Herzog is likewise concerned with fault detection and utilizes a monitor system that is wired into the array in advance of the combiners. It does not cover the combiners themselves.
12/582,367 US Patent Application 12/582,367 by Luebke et all describes a system of string protection devices, some of which are placed inside combiner boxes. The patent is primarily concerned with the prevention of arc faults in addition to more common faults like shorts.
12/637,873 US Patent Application 12/637,873 by Hastings et al describes a system similar to 12/582,367, using fault detection systems optionally included in the combiner.
The patent appears very similar to 12/582,367, including several Figures in common.
12/088,978 US Patent Application 12/088,978 by Thomspon et at describes a system of srring-level monitoring systems known as StringPAK. These are connected together into groups of up to 10 panels using combiner boxes. The application does not describe the combiner although it suggests the PCB10, which is a conventional metal NEMA3R combiner with conventional terminals.
12/562,933 US Patent Application 12/562,933 by Hadar et all describes a panel-level monitoring system connected to a conventional combiner.
12/487,564 US Patent Application 12/487,564 by Gervorkian likewise describes a system including panel-level monitoring that are built into arrays using conventional combiners.
10/679,814 Like CA 2542672, 10/679,814 describes a custom solar panel that includes electrical connectors as part of its structure. In this case the panels are flat sheets that connect together at the edges to form arrays. As in earlier examples, no consideration of string isolation is mentioned.
11/465,787 Another example of a custom panel/connector system is 11/465,787, which uses cabling extended from the edge of a frameless panel that are connected together using splicing units. As in earlier examples, no consideration of string isolation is mentioned.
Figure 12 and Figure 13 appear to show a combiner, but the associated text in paragraph [0051] describes item 204 as an inverter.
11/777,397 US Patent Application 11/777,397 covers a roofing system with solar panels built-in, which are combined with a custom combiner into strings and arrays.
In spite of this extensive search, it appears that only a single patent even attempts to address the same problem, 10/612,873. However, Brown's invention retains the idea of a single larger combiner, lacking the modularity of the current invention.
Additionally, it uses non-standard connectors throughout, which essentially eliminates its utility - which may be why there appears to have been zero adoption of this concept.
The rest of the patents discuss combiners and similar technologies only in passing.
as part of other technologies. None of these appear to even consider the wiring issues the present invention addresses. Only one, 12/796,466, even shows an electrical box like those used in the industry, and does so only because their design demands a custom connection system due to non-standard connector use.
Claims (21)
1.An electrical box, comprising essentially:
a.Mechanical enclosures of suitable construction and materials, and;
b.Internal mounting for required electrical circuitry and components.
a.Mechanical enclosures of suitable construction and materials, and;
b.Internal mounting for required electrical circuitry and components.
2.The electrical box of claim 1 further equipped with suitable frame grounding points, such as a grounding lug or screw.
3.The electrical box of claim 1 further equipped with electrical terminals suitable for connection to solar modules, strings or inverters.
4.The electrical box of claim 1 further equipped with electrical terminals suitable for connection to cabling to form a shared electrical bus.
5.The electrical box of claim 2 further equipped with circuitry connecting the terminals of claims 2 and 3 to the terminals of claim 4.
6.Suitable electrical bus cabling, comprising;
a.Electrical wiring of suitable capacity, and;
b.Fittings suitable for connection to the terminals in claim 4
a.Electrical wiring of suitable capacity, and;
b.Fittings suitable for connection to the terminals in claim 4
7.A string of solar modules comprising:
a. One or more solar modules connected together using their own cabling or that of their associated inverter's, and;
b.The unconnected ends of the electrical cabling of the modules attached to an electrical box of claim 1 on the terminals in claim 3, and;
c. Connections, if needed, between frame grounding of the string and the electrical box of claim 1 on the grounding point in claim 2.
a. One or more solar modules connected together using their own cabling or that of their associated inverter's, and;
b.The unconnected ends of the electrical cabling of the modules attached to an electrical box of claim 1 on the terminals in claim 3, and;
c. Connections, if needed, between frame grounding of the string and the electrical box of claim 1 on the grounding point in claim 2.
8.An array of solar modules, comprising;
a.One or more strings of modules and electrical boxes as in claim 7, and;
b.Electrical cabling between the electrical boxes of claim 7 using bus cabling of claim 6, and;
c.A suitable grounding point connected to the electrical bus of claim 6.
a.One or more strings of modules and electrical boxes as in claim 7, and;
b.Electrical cabling between the electrical boxes of claim 7 using bus cabling of claim 6, and;
c.A suitable grounding point connected to the electrical bus of claim 6.
9.An array of arrays of solar modules comprising;
a.One or more arrays of solar modules as in claim 8, and;
b.One or more combiner boxes as in claim 1, and;
c.One or more disconnection devices for array isolation, and;
d.One or more bus cables as in claim 5, and;
e.One or more bus cables as in claim 6 for connection to external electrical equipment or other examples of embodiments of this claim.
a.One or more arrays of solar modules as in claim 8, and;
b.One or more combiner boxes as in claim 1, and;
c.One or more disconnection devices for array isolation, and;
d.One or more bus cables as in claim 5, and;
e.One or more bus cables as in claim 6 for connection to external electrical equipment or other examples of embodiments of this claim.
10.A method of rapid assembly of strings of solar modules as in claim 7 through the electrical connection of solar modules to the electrical boxes as in claim 1 through 5 on the electrical terminals of claim 3.
11.A method of rapid assembly of arbitrary sized arrays of strings as in claim 8 connected to electrical boxes as in claim 1 through 5 using electrical cabling as in claim 6.
12.A method of rapid assembly of large arrays of modules as in claim 9 through electrical boxes as in claim 1 through 5 using cabling as in claim 6.
13.An electrical box as in claim 1 intended for junction box use made of molded PVC material to satisfy claim 1, a G-clamp grounding point to satisfy claim 2, compression fittings for attachment to arbitrary electrical equipment to satisfy claim 3, male and female screw-lock terminals to satisfy claim 4, and internal terminal block to satisfy claim 5.
14.An electrical box as in claim 13 intended for use as a string combiner with the addition of an integrated circuit breaker for circuit protection on the terminals intended for connection to the wiring from the compression fitting.
15.An electrical box as in claim 13 or 14 with an integrated string disconnection switch.
16.An electrical box as in claim 13, 14 or 15 that replaces the compression fitting with MC4 terminals on the outside of the box to satisfy claim 3 that are pre-wired to the circuitry of claim 5 produce a sealed unit.
17.An electrical box as in claim 16 replacing the MC4 connectors with Tyco Solarlok connectors.
18.An electrical box as in claim 16 replacing MC4 connectors with a single screw-lock terminals for attachment to micro-inverters of the Enphase M190 type to satisfy claim 3, and replacement of the screw-lock connectors with models suitable for 240V split-phase power to satisfy claim 4.
19.An electrical box as in claim of metal or fiberglass construction with lockable front-opening panel, integrated fuses, a visible blade disconnection device, and terminals suitable for connection to the electrical bus from boxes of claims 13 through 19 to satisfy claim 3.
20.An electrical box as in claim 19 with the addition of Cam-Lock fittings for rapid connection to other boxes to satisfy claim 4.
21.An electrical box as in claim 20 with the addition of screw-lock fittings for rapid connection to other boxes to satisfy claim 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2762078 CA2762078A1 (en) | 2011-12-16 | 2011-12-16 | Modular electrical connector apparatus and method for rapid assembly of photovoltaic arrays |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2762078 CA2762078A1 (en) | 2011-12-16 | 2011-12-16 | Modular electrical connector apparatus and method for rapid assembly of photovoltaic arrays |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2762078A1 true CA2762078A1 (en) | 2013-06-16 |
Family
ID=48652976
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2762078 Abandoned CA2762078A1 (en) | 2011-12-16 | 2011-12-16 | Modular electrical connector apparatus and method for rapid assembly of photovoltaic arrays |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2762078A1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107611878A (en) * | 2017-10-20 | 2018-01-19 | 中山市联进五金电器有限公司 | Multifunctional water-proofing, replaceable terminal junction box |
| US10008974B2 (en) | 2011-09-02 | 2018-06-26 | Pv Solutions, Llc | Mounting system for photovoltaic arrays |
| US10326278B2 (en) | 2011-09-02 | 2019-06-18 | Pv Solutions, Llc | System for tracking and allocating renewable energy contributions to a modular renewable energy system |
| EE01486U1 (en) * | 2019-03-26 | 2020-02-17 | Energogen OÜ | Method for creating a power production device |
| US10879835B2 (en) | 2015-01-28 | 2020-12-29 | Pv Solutions, Llc | Integrated electrical and mechanical photovoltaic array interconnection system |
| US11022343B2 (en) | 2011-09-02 | 2021-06-01 | Pv Solutions, Llc | Mounting system for photovoltaic arrays |
-
2011
- 2011-12-16 CA CA 2762078 patent/CA2762078A1/en not_active Abandoned
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10008974B2 (en) | 2011-09-02 | 2018-06-26 | Pv Solutions, Llc | Mounting system for photovoltaic arrays |
| US10326278B2 (en) | 2011-09-02 | 2019-06-18 | Pv Solutions, Llc | System for tracking and allocating renewable energy contributions to a modular renewable energy system |
| US11022343B2 (en) | 2011-09-02 | 2021-06-01 | Pv Solutions, Llc | Mounting system for photovoltaic arrays |
| US11063437B2 (en) | 2011-09-02 | 2021-07-13 | Pv Solutions, Llc | System for tracking and allocating renewable energy contributions to a modular renewable energy system |
| US10879835B2 (en) | 2015-01-28 | 2020-12-29 | Pv Solutions, Llc | Integrated electrical and mechanical photovoltaic array interconnection system |
| CN107611878A (en) * | 2017-10-20 | 2018-01-19 | 中山市联进五金电器有限公司 | Multifunctional water-proofing, replaceable terminal junction box |
| EE01486U1 (en) * | 2019-03-26 | 2020-02-17 | Energogen OÜ | Method for creating a power production device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9312665B2 (en) | Electrical distribution systems incuding parallel energy source and methods | |
| JP4664851B2 (en) | Solar power generation system and solar power generation plant | |
| CA2762078A1 (en) | Modular electrical connector apparatus and method for rapid assembly of photovoltaic arrays | |
| US8699209B2 (en) | Externally fused enclosure for a solar power system | |
| US20200287364A1 (en) | 7-Way Crab Joint | |
| JP2005507169A (en) | AC Photovoltaic Building Block | |
| US9397235B2 (en) | Photovoltaic string combiner with disconnect having provision for converting between grounded and ungrounded systems | |
| US20110308833A1 (en) | Photovoltaic string sub-combiner | |
| US9124077B2 (en) | Meter socket and load center combination apparatus, electrical distribution systems, and methods of assembly | |
| US20160149536A1 (en) | Solar Power Panels, Arrays and Connection Systems | |
| Wiles | Photovoltaic power systems and the 2005 National Electrical Code: suggested practices | |
| US9530595B2 (en) | Circuit breaker with low-clearance connections | |
| US20230133091A1 (en) | Patch panel for programming a split bus electrical panel for partial or full backup with pv and battery systems | |
| US11693031B2 (en) | Electric meter collar adaptor to divert power to distributed power generation resources | |
| EP3989394A1 (en) | Split-bus electrical panel with homeowner selectable partial or full back-up from pv/battery systems | |
| US20220013997A1 (en) | Electrical equipment with additional compartment and wiring to account for temperature limitations of connected conductors | |
| CN205543818U (en) | Alternating current -direct current lightning prevention box for photovoltaic power plant of family that can realize direct current side break -make | |
| Esmaeilian et al. | Comprehensive large-scale distribution test networks | |
| CN202602088U (en) | A contactor module, an inverter cabinet and a photovoltaic grid-connected inverting device | |
| US11979005B2 (en) | Multi-family metering device with modular meter compartments | |
| Simburger et al. | Engineering design for a central station photovoltaic power plant | |
| CN206547075U (en) | A kind of photovoltaic combiner box | |
| CN104821489A (en) | Cable branch box | |
| KR200321218Y1 (en) | Assembly Power Distribution Board | |
| CN111326983A (en) | Multi-circuit breaker arrangement method for ring main unit of urban 10KV distribution network |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |
Effective date: 20140709 |