Electrical cable harness and assembly for transmitting AC electrical power

An electrical connector/cable harness includes an electrically insulative housing and first and second passageways extending from a first end of the connector/cable harness to a second end thereof, first and second electrically conductive wires disposed in the passageways, respectively, wherein the passageways and the wires therein reverse their dispositions in the connector/cable harness such that at the second end of the connector/cable harness the two wires are disposed oppositely to their disposition at the first end of the connector/cable harness.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to assemblies for interconnecting AC generators and AC powered systems, and for converting solar energy to AC electrical power, and to electrical connector and cable harness means for interconnecting components of such assemblies.

2. Description of the Prior Art

Assemblies for converting DC sources of electrical energy, such as solar cells, batteries, and the like, to readily usable AC electrical power are known. However, current systems, particularly in the solar energy area, comprise a variety of components from multiple manufacturers. Such components in the solar energy area include photovoltaic cells, commonly referred to as solar cells, which convert solar energy to DC electrical power. Such cells are generally grouped in supporting and protective photovoltaic modules which are customarily mounted on roof tops, or other such structures, exposed to sunlight. The photovoltaic cells, and therefore, the photovoltaic modules, produce DC electrical power.

Usually, a number of photovoltaic modules are connected to an inverter which converts DC power output of the photovoltaic modules to AC power.

Photovoltaic systems usually include multiple DC photovoltaic modules connected in one or more series, or strings, feeding an inverter, which converts DC power to AC power. This system suffers from inefficiencies, such as module-to-module mismatch and power loss due to varying module orientations and significant shading losses. To connect one or more photovoltaic modules together to form a module string, there is provided a module cable harness including transmission wires and connector portions. A plurality of module and inverter strings may be connected to an AC buss by a module cable harness. The AC module buss may be connected to a junction box by a further cable harness with appropriate connector means.

The above described building blocks for photovoltaic power generating systems thus include DC generating photovoltaic modules, DC to AC inverters, DC and AC switches and other mechanical and electrical components.

Past AC modules have connected to a utility grid by utilization of an AC module cable harness which links AC module to AC module, functioning as both an AC physical string and an AC electrical buss.

The bussing of AC modules onto an AC power buss maintains the same AC voltage while it incrementally increases current with each AC module added. One or more strings/busses of AC modules are then connected to a combiner junction box to transition from the AC module cable harness to a runback wire to the service panel. The combiner junction box provides a terminal for transitioning the combined busses to a larger wire gauge and, optionally, overcurrent protection for each of the two AC busses.

The current state of the art for an AC module cable harness uses two, three-wire, quick connectors in the form of a male and female part and a three-wire cable connecting them. A single phase 120 volt AC module micro-inverter connects to the three-wire cable to make up the AC module buss. The micro inverter connects to line, neutral, and ground on the AC module buss.

In the current state of the art for two AC module strings connected to a combiner junction box, the two strings each are an AC module buss with a maximum of n modules. A standard AC module with a straight-through AC module cable harness connects to a combiner junction box in the center of two AC module strings of n modules.

AC modules must operate at the voltage of the grid to which they are interconnected. Typical USA residential and commercial grid services have available single-phase 120V, three-phase 120/208V, or split-phase 120/240V AC. It is desirable to have a product is operable on a 120V AC single phase line, because it is a universally available service voltage. In a residence, there is typically a split-phase 120/240V AC service available, consisting of two line conductors and a single neutral. The voltage between line and neutral is 120V AC. For typical commercial settings there is a three-phase 120/208V AC service that consists of three lines and a neutral. In this case, the voltage between a line and neutral is also 120V AC.

It also is desirable to connect as many AC modules on a single AC module string as possible, thereby avoiding additional junction boxes and service panel runback wires. In addition to adding cost, the junction box may require a roof penetration or may require a visible metal clad conduit, which installers try to minimize because of roof warranty issues and aesthetics.

The maximum number of AC modules on a buss depends on the AC module current rating, wire gauge and wire temperature rating. Higher temperature ratings and larger wire gauge increase the cost of the AC module cable harness. Therefore, as n increases, the cost of the AC module cable harness increases.

A limitation of the current AC module physical layout is that the junction box must be placed in a physical location that assures that it will accommodate the desired physical layout and electrical requirements of the AC module string.

SUMMARY OF THE INVENTION

An object of the invention is to provide an electrical connector which may be disposed as a component of an assembly for converting solar energy to AC electrical power, and/or in a cable harness or system by which AC components are connected to each other.

A further object of the invention is to provide an electrical cable harness for interconnecting an AC power source, such as a DC photovoltaic module and inverter, or a battery and inverter, or a wind or water turbine AC generator, to an AC power assembly.

A still further object of the invention is to provide a power generating assembly including a plurality of the aforesaid AC modules in communication with a junction box, and a line-alternating cable harness assembly which facilitates the communication.

A still further object of the invention is to provide the aforesaid power generating assembly wherein selected components of the power generating assembly and the cable harness assembly and the junction box are provided with connector means configured to physically engage and interlock with complementary connector means, the connector means being configured so as not to engage with each other unless properly paired, such that such connectors, and thereby the other components of the system, cannot be inappropriately interconnected. Any of the connecter/cable harness devices provided herein can be paired with any other like connector/cable harness and effect a correct connection for a buss.

The above and other objects and features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular device embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIG. 1, it will be seen that an electrical cable harness8, suitable for interconnection of components of an assembly for converting solar power to AC electrical power, includes an electrically insulative housing10having first and second ends12,14. A plurality of passageways16,18extend through the housing10from the first end12of the housing10to the second end14of the housing10.

The first passageway16, between the first and second connector ends12,14of the housing10, is provided with a first angled portion20extending to a portion22of the first passageway16in alignment with the second passageway18and extending to the second end14of the housing10.

Similarly, the second passageway18, between the first and second ends12,14of the housing10, is provided with a second angled portion24extending to a portion26of the second passageway18in alignment with the first passageway16and extending to the second end14of the housing10.

A plurality of electrically conductive elongated bodies30,32are disposed, respectively, in the plurality of passageways16,18and extend through the housing10from the first end12of the housing10to the second end14of the housing10, the electrically conductive bodies comprising at least the first and second electrically conductive bodies30,32.

Thus, at the second end14of the housing10, the first and second passageways16,18and therefore the first and second electrically conductive bodies30,32, are reversed in their positions relative to their dispositions at the first end12of the housing10.

The electrically conductive bodies30,32commonly comprise wires and may comprise a first line wire34and a second line wire36, respectively.

Referring toFIG. 1A, it will be seen that the plurality of passageways and electrically conductive elongated bodies which extend through the housing10may include a third passageway17, through which extends a neutral wire38. The passageway17and neutral wire38extend through the housing10from end12to end14so as to occupy the same position at the second end14of the housing10as it does at the first end12of the housing.

Similarly, and referring toFIG. 1C, it will be seen that the plurality of electrically conductive bodies which extend through the housing10may include a fourth passageway19in which there is disposed a ground wire44. The passageway19and the ground wire44extend through the housing10from end12to end14so as to occupy the same position at the second end of14of the housing10as it does at the first end12of the housing.

As shown schematically inFIG. 1B, assuming that an AC power source is connected to the line wire34and neutral wire38of a connector means28of a cable harness8, the pass-through wire46is not energized. The second connector means8′ is also connected to the line wire34′ and neutral wire38′ of an AC power source, and a pass-through wire46′ is not energized. When the connectors28are mated, the energized line34of the cable harness8mates to the pass-through wire46′ of the cable harness8′. The opposite is true for the cable harness8′, its line wire34′ connecting to the pass-through wire46of cable harness8.

As a result, two separate lines are created automatically, with a shared neutral wire, such that every other AC power source will be on the same line wire and adjacent AC power sources will be on the other line wire.

Each of the cable harness connector means is readily connectable to an identical connector means.

Referring to FIGS.2and3A-3D, it will be seen that the housings10may be provided with electrically conductive male pins40and electrically conductive female pins42mounted thereon and connected to the wires34,36,38and44in known fashion. The pins40,42are arranged such that cable harness connector means28are connectable to each other in only one orientation.

InFIGS. 3B,3C and3D there are depicted other connector pin arrangements for three wire connectors, including for example, combinations of first and second line wires34,36, neutral38and ground44wires.

The connector pins40,42are disposed on the connectors8,8′ by gender, location and conductor designations, such as line wires34,36, which serve also as pass-through wires, as will be discussed hereinbelow, a neutral wire38and, optionally, a ground wire44. The conductor pins40,42of each cable harness connector8,8′ are disposed symmetrically about two symmetry axes. InFIGS. 3A-3D, the first symmetry axis a-a is depicted by horizontal dashed lines and the second symmetry axis b-b by vertical dashed lines. Circles denote female conductor pins; circles with center dots denote male conductor pins.

The connector28is symmetrical about the first symmetry axis a-a which does not intersect any conductor pin40,42. The symmetry includes three attributes: location, gender (male, female) and designation (line, neutral, ground). A conductor pin40location is mirrored across the axis line a-a by a pin42of the opposite gender and of the same designation (i.e., line, neutral, ground).

The connector28is symmetrical about the second symmetry axis b-b, which is perpendicular to the first symmetry axis a-a, and which bisects line conductor pins40,42. A conductor pin40,42location is mirrored across the second symmetry axis b-b by a pin40,42, wherein genders are opposites and designations are common.

The aforesaid symmetry insures that a connector28is physically able to mate to an identical connector that is rotated 180 degrees, and insures that conductors of proper designation are electrically connected.

A hermaphroditic “pin”, as illustrated schematically inFIG. 1B, where the neutral wire connector pins52,521are both male and female, may be used, but the symmetries still prevail.

Referring toFIG. 4, it will be seen that customarily in the prior art, photovoltaic modules47(solar cells) are adapted for conversion of solar energy S to electrical power, more specifically direct current (DC). Inasmuch as usable power in households, businesses, and the like, is alternating current (AC), all such modules must be connected to an inverter48which converts DC energy to AC energy. Typically, a number of the solar cells47are in communication with an inverter48. Thus, in planning roof-top dispositions of solar cells and inverters, they must be organized such that an appropriate number and disposition of inverters is allowed for an appropriate number and disposition of solar cells.

Referring toFIG. 5, it will be seen that in accordance with the present invention, each photovoltaic module50includes a dedicated inverter48, enabling any number and disposition of photovoltaic modules50where the inverters are physically matched with the locations of modules. Such combinations of modules and inverters are herein referred to as “AC modules”50.

The AC module50is adapted for connection to a cable harness which may be provided with the wiring and cross-over feature illustrated inFIG. 1B. That is, the cross-over feature may be present in a cable harness, such that in the cable8, the line wires34and36reverse relative positions as they pass through the cable harness.

Referring still toFIG. 5, it will be seen that in an AC module cable harness8provided with a line wire34, a neutral wire38, a second line wire36serving as a “pass-through” wire and, optionally, an earth ground wire44, the electrical path for line wire34is switched with the pass-through wire36. The cable harness8also is provided with means to connect the cable harness to the AC output (electrical line L, neutral N, and ground G) of an AC module50.

Referring toFIG. 6, there are shown a plurality of AC modules50a,50b, and50cconnected to a junction box70. A ground wire44, a neutral wire38, and two line wires34,36interconnect the junction box70and a selected number of AC modules50a,50b, and50c, and any additional AC modules desired. The ground wire44and neutral wire38are in communication with each of the modules50a,50b, and50c, etc. However, the connector means8,8′ insure that only line wire36connects with modules50aand50c, and line wire34connects with the AC module50b. That is, every other AC module connects with line wire34and each AC module therebetween connects with line wire36. Thus, each line wire34,36at every other module becomes a pass-through wire, such that each line wire services one-half of the modules50in a string of modules.

Thus, twice as many AC modules can be connected together without exceeding the wire current carrying limit of the cable harnesses and related wiring. The AC module string requires only a standard junction box that can be located at an end of the string.

The line-alternating feature assures that approximately half the AC modules50are supplying current to one line34in the cable harness8and the current from the other half of the AC modules is supplied current to the other line wire36. Current is therefore balanced between the two AC lines34,36, unless there is an odd number of AC modules50. In the case of an odd number of AC modules, there is a small current imbalance between the two lines34,36. However, the maximum amount of the imbalance is no greater than the current limit of one AC module. In addition, the current traveling on the neutral wire38is defined as the current imbalance, and therefore will be no greater than the current limit of one AC module. There is thus provided a line-alternating harness8that insures that current on its two lines34,36is balanced to within the current limit of one AC module. The current on each line34,36of the line-alternating cable harness8is thus evenly balanced without special action required by an installer, and the maximum current on the neutral wire38is the current limit of one AC module. Accordingly, the current on the neutral wire is minimized.

A feature of the line-alternating cable harness8is that in any two neighboring AC modules50a,50bconnected to each other (FIG. 6) via a line-alternating cable harness8, one of the modules will be connected to the line wire34, and the other module will be connected to the line wire36. An advantage of the line-alternating cable harness is that each AC module50can be manufactured, including the line-alternating cable harness8, identically, while still maintaining the alternating pattern when connected together.

Thus, in a string of2nAC modules50a,50b, etc., n of the modules will be connected to a first line, and n of the modules will be connected to a second line. When the line-alternating cable harness connects to a junction box70(FIG. 6), the line wire and pass-through wire are both 120V AC buss lines relative to the neutral line38. The junction box70receives the two line wires34,36, neutral wire38, and optionally a ground wire44, and transitions directly to a 120/240V AC or 120/208V AC service. The junction box70can therefore accept two or more 120V AC module busses, with no need for overcurrent protection or transitioning to a larger gauge wire to a utility power service. Because each line in the line-alternating cable harness8can electrically carry the current for n AC modules, the total length of the AC module string can be 2n AC modules (FIG. 6).

A line-alternating cable harness that uses two line wires insures that each AC module added to an AC module string is connected to the opposite line from the previous AC module in the string, regardless of where the buss junction box is located or the presence of an extension cable in the string. Installers do not need specialized knowledge for connecting AC modules together in a string, or locating the junction box, thereby simplifying installations, reducing the cost and increasing the quality of installation.

The AC module50with a 120V AC output and a line-alternating cable harness can connect to either a 120/240V AC or a 120/208V AC standard junction box70at either end of the AC module string of up to 2n AC modules.

If a further connector is added to the standard junction box to create a buss junction box, then the junction box can be located at either end of the AC module string or at any location in between any two AC modules50a,50b,50c,50d,50e(FIG. 7). The buss junction box70passes the buss through, as at72, thereby maintaining the alternating pattern of the two lines34,36. An installer need not keep track of how many AC modules are on a particular line, as the modules will be evenly balanced between both lines.

An AC module50and a line-alternating cable harness8is adapted to connect to a 240V AC or 208V AC (wye) buss junction box70at any position along the AC module string of up to 2n modules (FIG. 7), thus having the flexibility to position a new buss junction box anywhere in the AC module string. Overcurrent protection and transitioning to larger wire size are unnecessary.

In addition to a junction box inserted between two AC module strings, it is sometimes necessary to extend an AC module cable harness to connect to an AC module that is not physically nearby. This may occur, for example, if an AC module string must avoid an obstacle on a roof, or when one AC module string needs to connect to another row or column of AC modules.

An extension cable62(FIG. 8) for a line-alternating cable harness8consists of a cable with a connector means28at each end. Electrically, the extension cable62functions as a pass-through. That is, no line wires are crossed from the first connector means28to the second connector means281in the extension cable62.

The benefit of the line alternating cable harness and junction box applies to a 208V AC-wye service connection, as well as a 240 volt service. The junction box70, with 2n AC modules, may be connected to two of the three wires34,36,44, as well as neutral wire38at, a service panel.

InFIG. 9there is shown a three-phase 120/208V AC service, with three separate AC module busses80, each comprising 2n AC modules50. The line-alternating wiring harness8creates two 120V AC lines in each of three junction boxes70. The output of each junction box70is then two lines34,36and a neutral line38. When each junction box connects to two separate legs of the three-phase service, a balanced connection is made with two 120 V AC module lines connected to each 120V leg of the three-phase service.

This benefit allows maximization of the current carrying capacity of a runback wire to a 208V AC service panel from three separated AC module strings80with2nmodules amounting to6nAC modules. This is achieved by fully balancing the three AC lines using three buss or end junction boxes70from the AC module strings80; one connected to service lines A and B, another to B and C and the third to C and A (FIG. 9).

Another embodiment of the three phase 208V AC configuration is a three-line, line-alternating harness shown inFIG. 10. In each cable harness8, there are two line wires34,36and a third line wire39which crosses over the line wires34,36. This embodiment creates a pattern that alternates the three active lines34,36,39over three sequential AC modules50,50a,50band then repeats. A total of 3n AC modules may be in a string that transitions to a buss junction box70. The junction box will then transition to a four-wire runback (including ground) that connects to three-wire 208V AC.

Thus, there is provided a line-alternating harness8that includes three line wires,34,36,39in an alternating pattern to create three 120V AC line outputs for use with a 208V AC-wye service. The current on each line of the 208VAC-wye service is evenly balanced within the output value of one AC module.

Accordingly, AC modules50,50a,50b, etc., can be connected to one another with no consideration by an installer for connector means “gender”. Furthermore, the combination creates a foolproof wiring method where the connection between an AC module50,50a,50band a junction box70, or an AC module and an extension cable62, will not break the pattern of the alternating lines. An installer, therefore, cannot create a hazardous connection along the AC buss or unbalance the AC buss. An AC module harness8is adapted to connect two or more AC modules in a row while maintaining the line-alternating feature.

While the cable harness/connector arrangement has been described hereinabove in conjunction with AC photovoltaic modules, it will be appreciated that the cable harness/connector is useful in conjunction with AC generators, such as wind and water turbines, and battery-inverter combinations.