Abstract:
A machine includes a high voltage element and an enclosure surrounding the high voltage element. The enclosure includes a first insulating insert disposed at least partially within a first wall and being electrically non-conductive and surrounding a first conductive insert and an enclosure cover formed at least partially of an electrically non-conducting substrate and having a first opening formed therein sized to allow a first fastener or an extension of the first conductive insert to pass through it. Removal of the enclosure cover causes the high high-voltage element to cease operating.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention is directed to machines, and, in particular, to disabling a machine having or located in an enclosure when a portion of the enclosure is opened. 
         [0002]    Technological advances have led to changes in the design of automobiles. For example, hybrid vehicles that include both a standard internal combustion engine (ICE) and an electric motor are now available. These vehicles typically have improved fuel economy as compared to a vehicle including only an ICE. 
         [0003]    Hybrid vehicles require electrical power at levels that far exceed the 12 to 24 volts at which ICE&#39;s operate in order to drive the electric motor. The motors can use batteries, ultracapacitors, fuel cells, or other sources to power the electric motor that drives the vehicle in some operating conditions. The voltage from these power sources are typically stepped up to a higher voltage and then provided to the motor. Transversely, when braking, the high voltage from the motor is stepped down and used to recharge the power sources. 
         [0004]    The elements involved in stepping the power up and down (as well as other devices) are typically located in a protective enclosure. The elements in the protective enclosure are referred to herein as “electrical elements” or “high voltage elements.” The enclosure keeps the electrical elements safe and prevents individuals from harming themselves by touching them. Such enclosures shall be referred to herein as “high voltage enclosures.” At times, a person may need to access electrical elements within the high voltage enclosure for service. In order to make such access safe and to reduce or remove the possibility of an electrical shock, the high voltage enclosure typically includes a mechanical switch that cuts the power supply to the electrical elements when an access cover of the enclosure is removed. The switches are typically connected to a high voltage interlock loop. That is, the power cannot be returned to the electrical elements until the switch is activated (opened or closed depending on orientation). In practice, the access cover is typically formed of metal to provide electromagnetic or radiofrequency shielding and includes a tab or other implement to activate the switch. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    Disclosed in one embodiment is a machine that includes a high voltage element and an enclosure surrounding the high voltage element. In this embodiment, the enclosure includes a first wall formed of an electrically conductive material, a first insulating insert disposed at least partially within the first wall and being electrically non-conductive, a first conductive insert at least partially disposed within the first insulating insert, and an enclosure cover formed at least partially of an electrically non-conducting substrate and having a first opening formed therein sized to allow a first fastener or an extension of the first conductive insert to pass through it. In this embodiment, the substrate includes a first conductor terminating at a first location at or near an edge of the first opening and a second conductor terminating at a second location at or near an edge of the first opening and separated from the first location. The first and second conductors are electrically coupled to one another through the first conductive insert when the enclosure cover is placed into contact with the first conductive insert and electrically isolated from one another when the enclosure cover is at least partially removed from contact with the first wall. 
         [0006]    Disclosed in another embodiment is a machine that includes a high voltage element and an enclosure surrounding the high voltage element. In this embodiment, the enclosure includes a first wall formed of an electrically non-conductive material, a first conductive insert at least partially disposed within the first wall, and an enclosure cover formed at least partially of an electrically non-conducting substrate and having a first opening formed therein sized to allow either a first fastener or an extension of the first conductive insert to pass through it. In this embodiment, the substrate includes a first conductor terminating at a first location at or near an edge of the first opening and a second conductor terminating at a second location at or near an edge of the first opening and separated from the first location, the first and second conductors are electrically coupled to one another through the first conductive insert when the enclosure cover is placed into contact with the first conductive insert and electrically isolated from one another when the enclosure cover is removed from contact with the first wall. 
         [0007]    Disclosed in another embodiment is a dynamoelectric machine that includes a high voltage element and an outer housing surrounding the high voltage element. In this embodiment, the outer housing includes a first wall formed of an electrically conductive material, a first insulating insert disposed at least partially within the first wall and being electrically non-conductive, and a first conductive insert at least partially disposed within the insulating insert. The dynamoelectric machine also includes an enclosure cover formed at least partially of an electrically non-conducting substrate and having a first opening formed therein sized to allow a first fastener or an extension of the first conductive insert to pass through it, the substrate including a first conductor terminating at a first location at or near an edge of the first opening and a second conductor terminating at a second location at or near an edge of the first opening and separated from the first location, the first and second conductors are electrically coupled to one another through the first conductive insert when the enclosure cover is placed into contact with the first conductive insert and electrically isolated from one another when the enclosure cover is at least partially removed from contact with the first wall. 
         [0008]    Disclosed in another embodiment is a machine that includes a high voltage element and an enclosure surrounding the high voltage element. The enclosure of this embodiment includes an insulating insert including an opening formed in a face thereof, a conductive trace formed within the opening and electrically connecting two locations within the opening, and an enclosure cover formed at least partially of an electrically non-conducting substrate and having a first conductor terminating at a first location and a second conductor terminating at a second location separated from the first location, the first and second conductors are electrically coupled to one another through the conductive trace when the enclosure cover is placed into the opening and electrically isolated from one another when the enclosure cover is removed from the opening. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
           [0010]      FIG. 1  depicts a block diagram of a machine in or on which embodiments of the present invention can be implemented; 
           [0011]      FIG. 2  depicts a bottom view of an access cover according to one embodiment; 
           [0012]      FIG. 3  is a cut-away side view of a high voltage enclosure having a cover according to one embodiment; 
           [0013]      FIG. 4  is a cut-away side view of a high voltage enclosure having a cover according to an alternative embodiment; 
           [0014]      FIG. 5  depicts a bottom view of an access cover according to another embodiment; 
           [0015]      FIG. 6  is a cut-away side view of a high voltage enclosure having a cover according to an alternative embodiment; 
           [0016]      FIG. 7  illustrates a conductive insert according to one embodiment; and 
           [0017]      FIG. 8  depicts a bottom view of an access cover according to another embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
         [0019]    Exemplary embodiments provide for a high voltage enclosure having a removable access cover. The cover is formed, in one embodiment, as a printed circuit board having at least two traces formed thereon and electrically separated from each other. When the access cover is secured to the high voltage enclosure it completes a safety circuit. When the access cover is removed, the safety circuit is opened. When opened, power is diverted from electrical elements in the high voltage enclosure to protect an individual. 
         [0020]      FIG. 1  illustrates a machine  100  in which embodiments of the present invention can be implemented. The machine  100  can be any type of machine and, in one embodiment, is a hybrid vehicle. In another embodiment, the machine  100  is an electric motor that is included in a vehicle. In yet another embodiment, the machine  100  is a hybrid engine that includes both an ICE and an electric engine 
         [0021]    The machine  100  includes a power supply  102 . In one embodiment, the power supply  102  is formed of one or more electrical power producing devices such as batteries, fuel cells, ultracapacitors or other devices capable of producing voltage and current (e.g., power) at their output. The power producing devices can be configured in series, parallel, or any other configuration. 
         [0022]    The power supply  102  can both produce and store power in one embodiment. The power supply  102  provides power to and receives power from a high voltage enclosure  104  over one or more conductors  106 . The high voltage enclosure  104  includes one or more electrical elements (e.g. a direct current (DC) to alternating current (AC) converter, a rectifier, or transformer) generally shown as element  107  that convert the power received from power supply  102  to a suitable level and frequency for operating the electric motor  110 . The high voltage enclosure  104  also includes, in one embodiment, one or more elements, generally shown as element  108 , for providing power from the electric motor  110  to the power supply  102  during regenerative braking. That operation and configuration of the components  107  and  108  can vary and is not limited to that shown in  FIG. 1 . 
         [0023]    The high voltage enclosure  104  can also include elements in addition to or instead of “high voltage” elements  107 ,  108 . As such, the enclosure  104  may also be referred to herein simply as an “enclosure.” In one embodiment, one or more of the elements  107 ,  108  in the enclosure  104  are coupled to a switch element  120  that, upon determining that the enclosure  104  has been opened, provides a signal to a controller (not shown) that causes power to be diverted from or otherwise removed from the elements  107 ,  108 . The operation of the controller is known in the art and not discussed further herein. In one embodiment, when the switch element  120  is opened, power ceases to be provided to one or more of the elements  107 ,  108 . 
         [0024]      FIG. 2  illustrates a bottom view of an access cover  200  according to one embodiment. In this embodiment, the access cover  200  includes portions of the switch element  120  shown in  FIG. 1 . The access cover  200  is formed of one or more layers of non-conducting material. For example, the access cover  200  is formed of a material from which a printed circuit board can be made such as (Teflon), FR-4, FR-1, CEM-1, CEM-3, FR-2 (Phenolic cotton paper), FR-3 (Cotton paper and epoxy), FR-4 (Woven glass and epoxy), FR-5 (Woven glass and epoxy), FR-6 (Matte glass and polyester), G-10 (Woven glass and epoxy), CEM-1 (Cotton paper and epoxy), CEM-2 (Cotton paper and epoxy), CEM-3 (Woven glass and epoxy), CEM-4 (Woven glass and epoxy), or CEM-5 (Woven glass and polyester). The access cover  200  can also include one or more conductive layers formed of, for example, copper. In  FIG. 2 , however, the illustrated substrate  201  is formed of a non-conductive material. 
         [0025]    As described above, the access cover  200  can be secured to and seal off entry to a high voltage enclosure. It should also be appreciated that the access cover  200  could alternatively be utilized with any type of dynamoelectric machine as is more fully described below. In one embodiment, the access cover  200  can form part of the switch element  120 . That is, in one embodiment, the removal of the access cover  200  from the enclosure causes the switch element  120  ( FIG. 1 ) to trip and, as such, power is diverted from or otherwise removed from elements within the enclosure. In the case where the access cover  200  is utilized with a dynamoelectric machine, removal of access cover  200  will cause a controller or other device to cause the machine to stop operating or otherwise prevent it from outputting a voltage that could harm an individual. 
         [0026]      FIG. 3  shows a cut-away side-view of an enclosure  104  according to one embodiment. The enclosure  104  illustrated in  FIG. 3  includes sidewalls  302  and a bottom  304 . In one embodiment, the sidewalls  302  are formed of an electrically non-conductive material. The bottom  304  can be formed of either an electrically conductive or non-conductive material. 
         [0027]    In use, the access cover  200  is coupled to one or more of the sidewalls  302  and covers the enclosure  104  such that a person cannot access elements  306  contained in an interior region  308  of the enclosure  104 . At least one of the sidewalls  302  includes a conductive insert  310 . The conductive insert  310  electrically couples two separate pieces of conductive material located at or near an edge of an opening in the substrate  200  through which a fastener  312  passes. The fastener  312  causes the conductive material to contact the conductive insert  310  and, thereby, electrically couples the two pieces of conductive material. 
         [0028]      FIG. 4  illustrates a cut-away side view of an alternative embodiment of an enclosure  400 . In this embodiment, the enclosure  400  includes sidewalls  402  and a bottom  404 . In this embodiment, the sidewalls  402  are formed of an electrically conductive material. This embodiment could exist, for example, in the case of a dynamoelectric machine. The enclosure  400  in such an embodiment could be, for example the housing of the dynamoelectric machine. In particular, the enclosure could be the housing of an electric motor or electric generator. The bottom  404  can be formed of either an electrically conductive or electrically nonconductive material. One or more of the sidewalls  402  include an insulating insert  406  disposed within it. The insulating insert  406  surrounds the conductive insert  310  and electrically isolates it from the sidewall  402 . 
         [0029]    Similar to as described above, in, the access cover  200  shown in  FIG. 4  is coupled to one or more of the sidewalls  402  and covers the enclosure  400  such that a person cannot access elements  306  contained in an interior region  308  of the enclosure  400 . The elements  306  could be, for example, the high voltage coils of an electric motor or electric generator in one embodiment. Of course, the elements  306  could be any other type of element and, in particular, any element typically contained in an electric motor or electric generator. 
         [0030]    At least one of the sidewalls  402  includes an insulating insert  406  that surround a conductive insert  310 . The insulating insert  406  could be formed as a single element that contain one or more inserts or could be formed as a plurality of elements, one for each conductive inserts utilized. The conductive insert  310  electrically couples two separate pieces of conductive material located at or near an edge of an opening formed in the substrate  200  through which a fastener  312  passes. The fastener  312  causes the conductive material to contact the conductive insert  310  and, thereby, electrically couples the two pieces of conductive material. 
         [0031]    Referring now to  FIGS. 2 to 4 , the substrate  201  includes one or more openings  202  through which fastener  312  may pass. As illustrated, the substrate  201  includes four openings  202   a ,  202   b ,  202   c  and  202   d . The number of openings  202  can be varied to suit the application. In one embodiment, the substrate includes one or more openings  202 . It shall be understood that the openings  202  could be holes as shown in  FIG. 2  or could be formed as cutout sections as illustrated in  FIG. 5 . In  FIG. 5 , the openings are labeled with reference numeral  502 . 
         [0032]    In general terms, the substrate  201  has formed thereon two or more connectors ( 230 ,  232 ,  234 ,  235 ,  236 ,  238 ,  240  and  242 ) that provide an electrical path between V+ and ground (or another reference potential) when the substrate  200  is arranged in a position such that a person cannot contact elements  306  in the interior region  308 . When the substrate  200  is removed, or the fasteners  312  loosened, V+ is separated from ground creating an open circuit. Such an open circuit can be detected. When the open circuit is detected (as in the prior art) power is no longer provided to or generated by the elements  306 . 
         [0033]    In more detail, the substrate  201  illustrated in  FIG. 2  includes a first conductor  230  formed thereon. In one embodiment, one or more of the conductors are formed of copper and the substrate is an electrically non-conductive material. In the prior art, the access (cover) was typically formed of metal to shield elements outside of the interior region  308  from interference from electromagnetic or radiofrequency energy created by elements  306 . For the purposes of the present invention, all that is required is that substrate  201  have at least a portion on which conductors can be integrally formed and electrically isolated from one another. 
         [0034]    As illustrated, the first conductor  230  is electrically coupled to a first opening first connector element  232 . The first opening first connector element  232  is formed at or near an edge of the first opening  202   a . A first opening second connector element  234  is formed on a different and separate portion of the substrate  201  such that it is electrically separated from the first opening first connector element  232  when the substrate  201  is removed from the enclosure. As illustrated, the first opening second connector element  234  is located at or near an edge of the first opening  202   a  As illustrated, the first opening second connector element  234  is electrically coupled to a second conductor  235 . The second conductor  235  electrically couples the first opening second connector element  234  to a second opening first connector element  236  that is located at or near an edge of the second opening  202   b . The second opening  202   b  also has a second opening second connector element  238  located at or near its edge and which is electrically (and physically) separated from the second opening first connector element  236 . The second opening second connector element  236  is electrically coupled to ground via second conductor  240 . 
         [0035]    It shall be understood that one or more openings  202  could be included between V+ and ground. As such, the configuration shown in  FIG. 2  is merely illustrative. In one embodiment, the first opening second connector element  234  is directly coupled to ground by third connector  242 . In such an embodiment, the elements identified by reference numerals  234 ,  235 ,  236  and  238  can be omitted. 
         [0036]    When the fastener  312  is mated with the conductive insert  310  it can bias the substrate  201  to the conductive insert  310 . In such a manner, the fastener  312  causes at least connector elements  232  and  234  to contact and form an electrical connection to the conductive insert  310 . As such, current can flow from V+ through first conductor  230  to first opening first conductor  232 . This current then travels through the conductive insert  310  to first opening second conductor  234 . However, when the fastener  312  is loosed or removed and/or the enclosure cover  200  is removed, the conduction path is broken and appropriate measures can be taken to ensure that an individual is not harmed by contact with elements  306 . The fastener  312  may be, for example, a screw, a bolt or other fastener that is configured to mate with the conductive insert  310 . In one embodiment, the fastener  312  is non-conducting so that it cannot provide a conduction path between conductors located at or near edges of the openings  202 . 
         [0037]    In the previous example it was assumed that a fastener would pass through an opening formed in the substrate and cause the conductors formed on the substrate to contact the conductive inserts  310 . It shall be understood, and as is shown in  FIG. 6 , the conductive inserts  310  could include an extension  602  that extends outwardly from the insulating insert  406  or the non-conductive sidewalls  302  shown in  FIG. 3 . 
         [0038]    In another embodiment, and as illustrated in  FIG. 7 , the conductive inserts  310  could be formed as a trace  610  formed internal to an insulating insert  600 . The trace  610  could be arranged to electrically couple to locations within an opening  612  formed in the insulating insert  600 . In such a case, a substrate carrying connections as described above or as shown in  FIG. 8 , for example, is inserted into the opening  612  to complete the connection between traces in a manner similar to that described above but without requiring the use of a fastener. 
         [0039]    Referring now to  FIG. 8 , a substrate  800  is shown carrying first and second conductors  802 ,  804 . These conductors are separated from one another by a gap  806 . This gap is bridged by trace  610  when substrate  800  is inserted into opening  612  ( FIG. 7 ). 
         [0040]    While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.