Abstract:
A static inverter assembly including a housing, a heat sink connected to the housing to define an enclosed three-dimensional volume, the heat sink including at least one channel extending therethrough, the channel including a plurality of cooling fins, a cooling fan positioned relative to the channel to encourage a fluid flow through the channel, and static inverter electronics positioned in the enclosed three-dimensional volume, wherein heat generated by the static inverter electronics is dissipated by the fluid flow through the heat sink.

Description:
[0001]    The present patent application claims priority from U.S. Ser. No. 60/851,981 filed on Oct. 16, 2006, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates to inverters and, more particularly, to static inverters for aircraft, marine and vehicle applications. 
         [0003]    Static inverters are used on board aircraft, marine vessels and motorized vehicles to convert direct current voltage, typically 12 or 28 volts DC, generated by the associated aircraft, vessel or vehicle, to alternating current suitable for operating accessories and peripheral equipment that may be on board. With some applications, typically military applications, a static inverter must be environmentally hardened; that is, the inverter must be enclosed within a case that is resistant to dust, electromagnetic frequencies (EMF), salt spray, oils and lubricants, and cleaning fluids and solutions. However, such an environmentally hardened enclosure must also be configured to dissipate the heat that is generated during operation of the inverter. It is also desirable to maximize the power generation by the inverter within a minimal space. 
       SUMMARY 
       [0004]    In one aspect, the disclosed static inverter with hardened environmental housing may include a housing, a heat sink connected to the housing to define an enclosed three-dimensional volume, the heat sink including at least one channel extending therethrough, the channel including a plurality of cooling fins, a cooling fan positioned relative to the channel to encourage a fluid flow through the channel, and static inverter electronics positioned in the enclosed three-dimensional volume, wherein heat generated by the static inverter electronics is dissipated by the fluid flow through the heat sink. 
         [0005]    In another aspect, In one aspect, the disclosed static inverter with hardened environmental housing may include a housing, a heat sink connected to the housing to define an enclosed three-dimensional volume, the heat sink including a plurality of generally elongated channels extending therethrough, each channel of the plurality of channels including a plurality of cooling fins, an inlet and an outlet, the inlet and the outlet being exposed to ambient atmosphere, at least one cooling fan positioned generally adjacent to at least one of the inlet and the outlet to encourage a fluid flow through the plurality of channels, static inverter electronics positioned in the enclosed three-dimensional volume, wherein heat generated by the static inverter electronics is dissipated to the ambient atmosphere by the fluid flow through the heat sink, and a connector disposed on the housing and in communication with the static inverter electronics. 
         [0006]    Other aspects of the disclosed static inverter with hardened environmental housing will become apparent from the following description, the accompanying drawings and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a front perspective view of the disclosed static inverter with hardened environmental housing; 
           [0008]      FIG. 2  is a rear elevation of the static inverter of  FIG. 1 ; 
           [0009]      FIG. 3  is a side elevation of the static inverted of  FIG. 1 ; 
           [0010]      FIG. 4  is a front perspective view of the heat sink of the static inverter of  FIG. 1 ; and 
           [0011]      FIG. 5  is a rear perspective view of the heat sink of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The present disclosure is directed to a lightweight, environmentally hardened static inverter that provides relatively high power density in a relatively small volume. These benefits are achieved through the use of an environmentally hardened enclosure that includes an efficient heat sink. 
         [0013]    Referring to  FIG. 1 , one aspect of the disclosed static inverter with hardened environmental housing, generally designated  10 , may include a housing  12  having longitudinal side walls  14 ,  16  and a top wall  18 . The housing  12  may also include front and rear end walls  20 ,  22 , respectively. The side walls  14 ,  16  and the top wall  18  may be unitary in construction and may include flanges  19  (see also  FIG. 2 ) that provide mounting surfaces for the end walls  20 ,  22 . The end walls  20 ,  22  may be attached to the side walls  14 ,  16  and top wall  18  by engaging the flanges  19  with a plurality of fasteners  24 , such as screws or the like. Optionally, O-rings, gaskets and the like may be positioned between the side and top walls  14 ,  16 ,  18  and the end walls  20 ,  22  to provide a seal from the environment and reduce or eliminate the passage of contaminants, such as dust and rain, across the housing  12 . 
         [0014]    The housing  12  may be formed from a durable and generally rigid materials, such as metal or hard plastic. Those skilled in the art will appreciate that the selection of material for the housing  12  may be dictated by the intended use of the static inverter assembly  10 . For example, naval applications may require a housing  12  capable of withstanding salt water exposure and large temperature fluctuations and, therefore, may be formed from an appropriate composite polymeric material. 
         [0015]    Referring to  FIGS. 2 and 3 , the bottom portion A of the static inverter assembly  10  may include a heat sink  26  that covers and encloses the underside of the housing  12 . In one aspect, the heat sink  26  may be connected to the housing  12  by fasteners  24 . However, those skilled in the art will appreciate that the heat sink  26  may be connected to the housing  12  in various ways, such as by being integrally formed with the housing  12 . The heat sink  26  may be made from a cast or extruded metal, such as aluminum alloy. For example, the heat sink  26  may be made by casting aluminum 356/T6 alloy or extruding 6063 aluminum alloy. 
         [0016]    While the side walls  14 ,  16  are shown as extending to cover the heat sink  26  (see  FIGS. 1-3 ), those skilled in the art will appreciate that the side walls,  14 ,  16  could be shorter and could be attached to a corresponding flange (not shown) extending upwardly from the top surface  34  of the heat sink  26 . 
         [0017]    Referring to  FIGS. 4 and 5 , the heat sink  26  may include three interior channels  28 ,  30 ,  32  extending therethrough and having an inlet ( FIG. 4 ) and an outlet ( FIG. 5 ). As shown in  FIG. 1 , the front end wall  20  of the housing  12  may include a cutout or cutouts  75  sized and shaped to align with the channels  28 ,  30 ,  32  of the heat sink  26  and expose the channels to the environment. The cutouts  75  may be protected by grates  82  connected to the housing  12  and positioned over the cutouts. Furthermore, as shown in  FIG. 2 , the rear end wall  22  of the housing  12  may include a cutout portion  76  sized and shaped to align with the channels  28 ,  30 ,  32  of the heat sink  26  and expose the channels to the environment. The cutout portion  76  may be protected by a grate (not shown) similar to grates  82 . 
         [0018]    While reference is made to three channels in the present description and only three channels are illustrated in the drawings, those skilled in the art will appreciate that the heat sink  26  may be provided with a greater or fewer number of channels. 
         [0019]    The heat sink  26  may include a top wall  34 , two side walls  36 ,  38 , a bottom wall  40  and two end walls  42 ,  44 . The rear end wall  42  of the heat sink  26  may be sized and shaped to engage the end wall  22  of the housing  12  (see  FIG. 1 ). The front end wall  44  of the heat sink  26  may include a notch  46  sized and shaped to receive one or more cooling fans  47  ( FIG. 3 ) therein. An example of an appropriate cooling fan  47  includes a Model MD4028 series high performance DC fan manufactured by Mechatronics Corp. of Preston, Wash. The notch  46  may extend the width of the heat sink  26 . The outermost edges  48 ,  50  of the end  44  may be shaped to engage the end wall  20  of the housing  12  (see  FIG. 3 ). 
         [0020]    The channels  28 ,  30 ,  32  may be substantially the same in construction or, alternatively, one or more of the channels  28 ,  30 ,  32  may have a different geometry than the other channels. In one aspect, each channel  28 ,  30 ,  32  may include side walls  52 ,  54 , a top wall  56  and a bottom wall  58 . The walls  52 ,  54 ,  56 ,  58  may be offset in a cruciform pattern such that a generally “I-beam” structure  60  is formed between adjacent channels. The walls  52 ,  54 ,  56 ,  58  may include inwardly extending cooling fins  62  that may extend the entire length of the channel  28 . Connective cooling fins  64 ,  66 ,  68 ,  70  may be provided that extend across the entire width of the channel  28  to provide structural support. However, those skilled in the art will appreciate that various numbers, arrangements and geometries of cooling fins may be used without departing from the scope of the present disclosure. 
         [0021]    Thus, the housing  12  and the heat sink  26  connected thereto may define a three-dimensional volume in which static inverter electronics  29  ( FIG. 3 ) may be contained. 
         [0022]    As shown in  FIG. 1 , the end panel  20  may include a plug connector  78  and other connectors  80  that allow a user to interface with the static inverter electronics  29  ( FIG. 3 ). An example of an appropriate connector  80  is a Model 2201 terminal feed-through connector manufactured by Blue Sea Systems, Inc. of Bellingham, Wash. 
         [0023]    Without being limited to any particular theory, it is believed that the I-beam structures  60  ( FIGS. 2 ,  4  and  5 ) conduct heat from the top surface  34  of the heat sink  26 , which receives heat from the static inverter electronics  29  within the housing  12  (see  FIG. 3 ), such that the heat is radiated from the cooling ribs  62 ,  64 ,  66 ,  68 ,  70  and transferred to the fluid (e.g., air) passing through the channels  28 ,  30 ,  32 . The cooling fan  47  ( FIG. 2 ) may increase convective heat transfer in the channels  28 ,  30 ,  32 . Therefore, the heat sink  26  may convey a maximum amount of heat to the ambient atmosphere from the electronics positioned on or above the upper surface  34  of the heat sink  26 . 
         [0024]    Although various aspects of the disclosed static inverter with hardened environmental housing have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.