The present disclosure relates, generally, to photovoltaic (PV) modules and, more particularly, to photovoltaic modules having a power inverter integrated therewith for converting direct current (DC) power generated by the PV module to alternating current (AC) power.
A typical DC PV module generally includes a rectangular frame (typically aluminum), a PV laminate, and a junction (j-) box. Standard (silicon) PV modules typically have 60 or 72 solar cells, arranged electrically in a three or four series-connected “substrings.” Each substring will typically have an equal number of cells (e.g., 20 cells for a 60-cell module) and have a bypass diode placed in parallel with the series cells.
A typical j-box has a plastic housing containing those bypass diodes, which are often mounted on a small printed circuit board, and two PV wires (a positive and negative) to carry DC power from the module. The PV wires or cables are typically of the double-insulated type and have rugged connectors, commonly known as “MC-4” connectors. The PV wires carry the DC power from the module to an external circuit.
The PV module typically has “tabs” or “ribbon connectors” protruding from the backsheet of the laminate, which are used to connect the module to the diodes, printed circuit board (PCB), and PV wires. These tabs are typically placed near one edge of the module, along the center of the frame on that edge, and the j-box is normally glued to the laminate backsheet proximate to these tabs. This may aid the installer of the module as he/she places the module on a rack, he/she can easily reach under the module and grab the wires and make connections to adjacent modules.
In particular applications, the DC power generated by a DC PV module may be converted to AC power through the use of a DC-to-AC power inverter. The power inverter may be electrically coupled to the DC output of the PV module (i.e., the PV cables). The power inverter may be located physically apart from the PV module, with only the intervening wiring and associated hardware physically coupling the PV module to the power inverter.
According to one aspect of the disclosure, an inverter for a photovoltaic module is disclosed. The inverter includes a housing having a first surface configured to confront the photovoltaic module and a second surface opposite the first surface, and a plurality of terminals coupled to the housing. Each terminal is configured to connect with a direct current (DC) output of the photovoltaic module. The inverter also includes an alternating current (AC) connector positioned in an aperture defined in the second surface, a circuit board positioned between the plurality of terminals and the AC connector that is configured to convert DC power to AC power, and an access door configured to cover an opening defined in the second surface. The access door is moveable between a first position in which the plurality of terminals are accessible through the opening and a second position in which access to the plurality of terminals is prevented.
In some embodiments, the access door may be removable from the housing to permit access to the plurality of terminals. The second surface of the housing may have a plurality of fins formed thereon.
In some embodiments, the inverter may also include a plurality of diodes, and each diode may be associated with a corresponding terminal of the plurality of terminals.
In some embodiments, the aperture may define a cross. The AC connector may include a first set of pins positioned in a first orientation, a second set of pins positioned in a second orientation different from the first orientation, and each of the first set of pins and the second set of pins may provide a complete electrical connection such that the second set of pins is redundant to the first set of pins.
In some embodiments, the second orientation may be positioned orthogonal to the first orientation.
According to another aspect, an alternating current photovoltaic (ACPV) module is disclosed. The ACPV includes a photovoltaic module having a direct current (DC) output, and an inverter positioned over the DC output connector. The inverter includes a housing secured to the photovoltaic module, a DC input connector connected to the DC output connector, an alternating current (AC) connector, a circuit board positioned between the DC input connector and the AC connector that is configured to convert DC power to AC power, and an access door configured to cover an opening defined in the outer surface of the housing. The access door is moveable between a first position in which the DC input connector and the DC output connector are accessible through the opening and a second position in which access to the DC input connector and the DC output connector is prevented.
In some embodiments, the DC output connector of the photovoltaic module may include a plurality of pins extending from a back surface thereof.
In some embodiments, the DC input connector may include a plurality of spring clips.
In some embodiments, the access door may be removable from the housing to permit access to the DC input connector and the DC output connector.
In some embodiments, the inverter may further include a plurality of diodes.
In some embodiments, the outer surface of the housing may have a plurality of fins formed thereon.
Additionally, in some embodiments, the photovoltaic module may include a support frame, and the housing of the inverter may be secured to the support frame via a mechanical fastener. In some embodiments, the alternating current (AC) connector may be positioned in an aperture defined in an outer surface of the housing
According to another aspect, an inverter for a photovoltaic module may include a housing having a first surface configured to confront the photovoltaic module, a second surface opposite the first surface, and a connection chamber positioned between the first surface and the second surface. A plurality of electrical terminals may be positioned in the connection chamber, and each terminal may be configured to connect with a direct current (DC) output terminal of the photovoltaic module. A plurality of alternating current (AC) terminals may be positioned in an aperture defined in the second surface of the housing. A circuit board positioned between the plurality of pins and the AC connector may be configured to convert DC power to AC power. The inverter may also include an access door configured to cover the connection chamber. The access door may be moveable between a first position in which the plurality of electrical terminals are accessible and a second position in which access to the plurality of electrical terminals is prevented.
The concepts described herein are illustrated by way of example and not by way of limitation in the accompanying figures. For simplicity and clarity of illustration, elements illustrated in the figures are not necessarily drawn to scale. Where considered appropriate, reference labels have been repeated among the figures to indicate corresponding or analogous elements.
While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will be described herein in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives consistent with the present disclosure and the appended claims.
References in the specification to “one embodiment,” “an embodiment,” “an illustrative embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may or may not necessarily include that particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. Additionally, it should be appreciated that items included in a list in the form of “at least one A, B, and C” can mean (A); (B); (C): (A and B); (B and C); or (A, B, and C). Similarly, items listed in the form of “at least one of A, B, or C” can mean (A); (B); (C): (A and B); (B and C); or (A, B, and C).
In the drawings, some structural or method features may be shown in specific arrangements and/or orderings. However, it should be appreciated that such specific arrangements and/or orderings may not be required. Rather, in some embodiments, such features may be arranged in a different manner and/or order than shown in the illustrative figures. Additionally, the inclusion of a structural or method feature in a particular figure is not meant to imply that such feature is required in all embodiments and, in some embodiments, may not be included or may be combined with other features.
Referring now to
The output leads or cables from the microinverter carry AC power rather than the DC power generated by the PV module. Typically, the AC cables are configured to connect adjacent modules electrically in parallel and are assembled in a cable jacked with a connector. These wires are often connected in what looks like a daisy chain fashion normally used for DC wires, but in fact the connections are in parallel, rather than series. Since normally three or four AC wires are needed (e.g., line-1, line-2, ground, and neutral, depending on the target market), the cable assembly can be relatively expensive and unwieldy.
One embodiment that has been implemented to address the challenges of a typical ACPV module is illustrated in
In this approach, the slots 24 facilitate flush screw connections. In past frame attachments, a need existed for different mechanical designs to mate with the different types of frames made by various manufacturers. The slots 24 permit the entire microinverter 12 to be “flush” with the frame 26 of the module 14 without features that protrude from the plane of the frame 26. It should be appreciated that holes defined in the frame and microinverter can both be threaded to avoid hardware (such as nuts). It should be appreciated that in other embodiments the outer housing 18 and/or the frame 26 may include other tabs, flanges, slots, or other mechanical fastening devices to secure the microinverter 12 to the PV module 14. In still other embodiments, the microinverter may be attached using an adhesive such as glue.
The outer housing 18 of the microinverter 12 is illustratively formed from a polymeric material such as, for example, molded plastic. The housing 18 has an outer surface 40 that faces away from the PV module 14 when the housing 18 is attached thereto. As shown in
In the illustrative embodiment, the housing 18 includes an inverse skyline 44 that follows the overall surface of the internal electrical components, including, for example, the circuit board 16. The skyline 44 minimizes the empty space within the housing 18 and potentially saves on cost by reducing the amount of encapsulation material (such as potting) that may be required. The skyline feature 44 may be hollow or filled with more fins such that heat removal may be further aided.
The housing 18 may also include a number of features such as, for example, internal standoffs. Additionally, the circuit board 16 may be oriented such that the “tall” components of the board 16 are protruding away from the backsheet (such that when the module 10 is installed, the components point toward the roof).
As shown in
The panel 52 acts as an access door that selectively permits and prevents access to the connection chamber 54. In the illustrative embodiment, the panel 52 may be completely detached from the housing 18. It should be appreciated that in other embodiments the panel 52 may be attached to the housing 18 via a hinge or other fastening device. The panel 52 also include a seal (not shown) that seals the opening 50 when the panel 52 is attached to the housing 18. The seal may be an o-ring, gasket, or other features that prevents environmental ingress. The panel 52 may also include a Gore-type pressure equalization vent to address the ingress of moisture.
As shown in
Each of the DC output tabs accesses a connection point inside the laminate of the PV module 14. In the case of a 60-cell module, all 60 cells are in series, but there are taps at each end of the string as well as taps at the 20- and 40-cell connection points as well for a total of four connections. By bringing all four points into the microinverter 12, the bypass diodes (or their equivalent function) can be managed inside the microinverter 12, thus offsetting some cost of the module. The DC output tabs of the PV module 14 can be bonded (normally with solder, but perhaps with electrical spring clips or other means) to the respective terminals 56 on the section 66 of the circuit board 16. Once this is done, the chamber 54 can be sealed with potting or coating as desired and then the panel 52 closed and, if necessary, sealed shut.
Returning to
Correspondingly, the trunk cable 100 includes a plug 102 that has a single ground pin 104 (center), a pair of line-1 pins 106, a pair of line-2 pins 108, and a pair of neutral pins 110, as shown in
As described above, the circuit board 16 is encased within the housing 18. While the circuit board 16 includes a section 66 that is positioned in the connection chamber 54, the remainder of the board 16 is sealed within the housing 18. In that way, the other electrical components, including bypass diodes (not shown) are insulated from the operational environment of module 10. Those electrical components receive DC power from the terminals 56, convert that power to AC power, and supply the AC power to the AC connector 80.
In the illustrative embodiment, the microinverter 12 may be assembled separately from the PV module 14. Integration of the two may be accomplished by attaching the microinverter 12 (with open panel 52) to the PV module 14. The DC output tabs of the PV module 14 can be bonded (normally with solder, but perhaps with electrical spring clips or other means) to the respective terminals 56. Once this is done, the chamber 54 can be sealed with potting or coating as desired and then the panel 52 closed and, if necessary, sealed shut.
As shown in
Referring now to
In the illustrative embodiment, the housing 218 includes an inverse skyline 244 that follows the overall surface of the internal electrical components, including, for example, the circuit board 216. The skyline 244 minimizes the empty space within the housing 218 and potentially saves on cost by reducing the amount of encapsulation material (such as potting) that may be required. The skyline feature 244 may be hollow or filled with more fins such that heat removal may be further aided.
As shown in
The panel 252 acts as an access door that selectively permits and prevents access to the connection chamber 254. In the illustrative embodiment, the panel 252 may be completely detached from the housing 218. It should be appreciated that in other embodiments the panel 252 may be attached to the housing 218 via a hinge or other fastening device. The panel 252 also include a seal (not shown) that seals the opening 250 when the panel 252 is attached to the housing 218.
As shown in
As shown in
As described above, the circuit board 216 is encased within the housing 218. While the circuit board 216 includes a section 286 that is positioned in the aperture 282, the remainder of the board 216 is sealed within the housing 218. In that way, the other electrical components, including bypass diodes (not shown) are insulated from the operational environment of module 210. Those electrical components receive the DC power from the terminals 256, convert that power to AC power, and supply the AC power to the AC connector 280.
As shown in
Various technologies for integrating a microinverter with a PV module have been illustrated in the Figures and described above. Although particular features have been shown and described with regard to particular embodiments, it should be appreciated that features of various embodiments may be mixed and matched as each implementation may require. For example, in some embodiments, a “standardized” microinverter may be desired for use with a variety of PV modules (which may vary in frame size and/or placement of electrical connections/junction box). Additionally, it may be desirable to uniformly locate features of the PV module across different PV modules for ease of manufacturability or certification. In such embodiments, features of the various disclosed embodiments may be selected to adapt the microinverter to each PV module as desired.
This application claims priority under 35 U.S.C. §119 to U.S. Patent App. Ser. No. 61/922,146, which was filed on Dec. 31, 2013 and is expressly incorporated herein by reference.
This invention was made in part with government support under Grant No. DE-EE0005341 awarded by the Department of Energy. The Government has certain rights in this invention.
Number | Date | Country | |
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61922146 | Dec 2013 | US |