Patent Publication Number: US-2011073158-A1

Title: Photovoltaic device and power supply apparatus thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to photovoltaic device and power supply apparatus thereof. 
     2. Description of Related Art 
     Since photovoltaic devices directly converse solar energy into electricity without generating any greenhouse gas or pollutant and provide safe power sources, they are helpful to reduce greenhouse gas emissions and provide stable energy supplies. Conventionally, a pillar is inserted into a foundation so as for a photovoltaic module to be disposed thereto. However, the construction of the foundation consumes a lot of time, area, effort and money. Meanwhile, the pillar is not suitable to be disposed on a roof. 
     Accordingly, a module suitable to be disposed on the roof is developed. As shown in  FIG. 1 , a conventional photovoltaic device  1  comprises three photovoltaic modules  10  each provided thereon with a lens assembly  100 , an actuating rod group  11  for supporting and actuating the photovoltaic modules  10 , a circular track  13 , a supporting member  14  for moving the photovoltaic module  10  along the track  13 , and a detection actuating unit  15  for controlling operation of the actuating rod group  11  and the supporting member  14 . As such, the photovoltaic device is suitable to be disposed on the roof, easy to assemble and meanwhile the construction of the foundation is dispensed with. 
     The actuating rod group  11  comprises pivot point rods  111 , an active rod  112 , coupling rods  114  and an assisting rod  113 . The pivot point rods  111  are disposed at the bottom of the photovoltaic modules  10 . The active rod  112  has one end thereof slidingly disposed on the rod body of the rear pivot point rod  111  and the other end thereof connected to the assisting rod  113 . Further, the assisting rod  113  is connected to the coupling rods  114  that are connected to the lower portion of the lens assembly  100 . 
     During operation of the photovoltaic device  1 , the active rod  112  is moved upwards or downwards by the detection actuating unit  15  to thereby move the assisting rod  113  forwards or backwards, which further causes the coupling rods  114  to swing such that the lower portions of the photovoltaic modules  10  swing about the pivot rods  111 , thereby adjusting the elevation of the lens assemblies  100 . Further, solar the photovoltaic modules  10  can be turned eastwards or westwards corresponding to the path of the sun by controlling the operation of the supporting member  14  and the wheel train  140  of the supporting member  14  through the detection actuating unit  15 . 
     However, in the conventional photovoltaic device  1 , since the distance between the photovoltaic modules  10  is small, the front photovoltaic modules  10  may cast a shadow W on the rear photovoltaic module  10 . Since the height of the sun in the four seasons of a year is different, the area of the shadow W is also different, which adversely affects the light collecting efficiency of the whole year. If the distance between the photovoltaic modules is increased to prevent the shadow W, the occupation area of the track  13  needs to be greatly increased according to the lowest height of the sun in the four seasons. As such, it is difficult for the device to be disposed on the roof. 
     Therefore, it is imperative to overcome the above drawbacks of the prior art. 
     SUMMARY OF THE INVENTION 
     In view of the above drawback, the present invention provides a photovoltaic device and power supply apparatus thereof so as to enhance the light collecting efficiency. The power supply apparatus according to the present invention comprises: a first carrier functioning as a base; a second carrier disposed above the first carrier at an adjustable angle of inclination relative to the first carrier; a plurality of light collecting units disposed on the second carrier and each having a lens assembly, a solar cell module, first side portions being formed close to the lens assembly and second side portions being formed proximate to the first side portions, the first side portions being pivotally connected to the second carrier; and an actuating rod group comprising a plurality of coupling rods pivotally connected to the second side portions of the light collecting units, and an active rod capable of moving the coupling rods so as to enable the light collecting units to swing, thereby adjusting the elevation of the lens assemblies. 
     Therein, the second carrier has a plurality of pivot portions pivotally connected to the first side portions of the light collecting units, respectively. The power supply apparatus further comprises a plurality of supporting rods each having one end thereof pivotally connected to the first carrier and another end thereof disposed on the second carrier, wherein said another end is extended or retracted relative to said one end so as to adjust the angle of inclination of the second carrier with respect to the first carrier. In another embodiment, the actuating rod group further comprises an assisting rod connected to the active rod slidingly disposed on the first carrier. The active rod moves the assisting rod and the coupling rods so as to enable the second side portions of the light collecting units to swing. The actuating rod group further comprises a position limiting rod slidingly disposed on the first carrier for limiting the position of the assisting rod. The position limiting rod is connected between the first and second carriers and is capable of being extended or retracted so as for the length of the position limiting rod to be adjusted. 
     The light collecting units are arranged in at least one row and each has a casing for receiving the lens assembly and the solar cell module, the lens assembly being exposed from the casing and the solar cell module being located inside the casing and corresponding in position to the lens assembly such that solar radiation is focused on the solar cell module through the lens assembly. 
     The present invention further provides a photovoltaic device, which comprises: at least two above-described power supply apparatuses arranged in tandem; and a track rotatably supporting the first carriers so as to change the azimuth of the light collecting units corresponding to the path of the sun such that the sunlight falls on the lens assemblies at an optimum angle. 
     The track is of a circular shape. The first carrier further comprises a wheel train slidable and configured to move along the track. The first carrier is further provided with a supporting frame on which the wheel train is disposed. In addition, the first carrier can comprise a plurality of supporting members disposed between the supporting frame and the wheel train so as for the power supply apparatuses to slidingly move along the track. 
     According to the present invention, the actuating rod group causes the light collecting units to swing with an amplitude corresponding to the position of the sun so as for the lens assemblies to face the sunlight, thereby enhancing the light collecting efficiency. Further, the supporting rods can be adjusted to change the height of the second carrier corresponding to the height of the sun in the four seasons. Furthermore, the present invention prevents the front power supply apparatus from casting a shadow on the rear power supply apparatus without the need of increasing the distance therebetween and accordingly enhances the light collecting efficiency compared with the prior art. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a conventional photovoltaic device; 
         FIG. 2A  is a perspective view of a power supply apparatus according to the present invention; 
         FIG. 2B  is an exploded view of the power supply apparatus according to the present invention; 
         FIG. 3  is a perspective view of a light collecting unit of the power supply apparatus according to the present invention; 
         FIGS. 4A and 4B  are operational views of an actuating rod group of the power supply apparatus according to the present invention; 
         FIGS. 5A and 5B  are operational views of supporting rods of the power supply apparatus according to the present invention; 
         FIG. 6A  is a perspective view of a photovoltaic device according to the present invention; 
         FIG. 6B  is an azimuth definition diagram for the sun; and 
         FIG. 7  is a perspective view of a photovoltaic device according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The following illustrative embodiments are provided to illustrate the disclosure of the present invention, these and other advantages and effects can be apparent to those skilled in the art after reading the disclosure of this specification. 
     Referring to  FIGS. 2A and 2B , a power supply apparatus  2  used for converting solar energy into electrical energy comprises: a first carrier  21 , a second carrier  22 , a plurality of supporting rods  23   a ,  23   b  connecting the first and second carriers  21 ,  22 , a plurality of light collecting units  20  disposed on the second carrier  22 , and at least an actuating rod group  24  for bringing the light collecting units  20  to swing. 
     The first carrier  21  comprises five portions  21   a ,  21   b ,  21   c ,  21   d  and  21   e , which serves as the base of the power supply apparatus and is mounted on such as a roof. The second carrier  22  comprises three rods  22   a  and a plurality of pivot portions  220 , which is disposed above the first carrier  21 . 
     Three supporting rods  23   a ,  23   b  each have one end thereof connected to the first carrier  21  and another end thereof connected to the second carrier  22 , wherein three supporting rods  23   a  and three supporting rods  23   b  are provided at the front and rear sides of the second carrier, respectively, such that the second carrier  22  is angularly disposed relative to the first carrier  21 . The supporting rods  23   a  rotatably support the front side of the second carrier  22  and the height of the rear side of the second carrier  22  can be adjusted through the supporting rods  23   b  so as to adjust the distance between the first and second carriers  21 ,  22 . 
     In the present embodiment, the supporting rods  23   a  each have one end thereof fixed in position to the first carrier  21  and another end thereof pivotally connected to the second carrier  22 ; and the supporting rods  23   b  each have one end thereof pivotally connected to the first carrier  21  and another end thereof slidingly disposed to the second carrier  22  so as to adjust the maximum distance between the first and second carriers  21 ,  22 . 
     The light collecting units  20  are arranged on the second carrier  22  one behind another in a row. In the present embodiment, there are two rows of the light collecting units  20 , but it is not limited thereto. The light collecting units  20  each have first side portions  20   a  and second side portions  20   b . In the present embodiment, the first side portions  20   a  are located at the upper portion of the light collecting unit  20  and the second side portions  20   b  are located at the lower portion of the light collecting unit  20 , and the first side portions  20   a  are pivotally connected to the pivot portions  220  of the second carrier  22 , respectively. 
     In particular, referring to  FIG. 3 , the light collecting units  20  each have a lens assembly  201 , a solar cell module  202 , and a casing  200  for receiving the lens assembly  201  and the solar cell module  202 . The lens assembly  201  is disposed on the top of the casing  200  (at a sun-facing region between the two adjacent first side portions  20   a ) and exposed from the casing  200 . The solar cell module  202  is disposed on the bottom of the casing  200  (at a region between the two adjacent second side portions  20   b ) to correspond in position to the lens assembly  201  such that solar radiation is focused on the solar cell module  202  through the lens assembly  201 . But it should be noted that the structure of the light collecting units is not limited to the above embodiment. 
     Referring to  FIGS. 4A and 4B , the actuating rod group  24  is slidingly disposed on the first carrier  21  and pivotally connected to the second side portions  20   b  of the light collecting units  20 . When the actuating rod group  24  moves on the first carrier  21 , it brings the light collecting units  20  to swing. 
     In particular, the actuating rod group  24  has an active rod  240  and a plurality of coupling rods  241 . The active rod  240  has one end thereof slidingly disposed on the first carrier  21  and the other end thereof fixed in position to the coupling rods  241 . The coupling rods  241  are pivotally connected to the second side portions  20   b  of the whole row of the light collecting units  20 . In the present embodiment, at least two coupling rods  241  are provided at the two sides of the light collecting units  20  so as to bring the light collecting units  20  to swing in a balanced manner. The actuating rod group  24  further comprises assisting rods  242   a ,  242   b  connected to the active rod  240  and the coupling rods  241  so as for the single active rod  240  to move the coupling rods  241 . It should be noted that since there are various kinds of methods for slidingly disposing the active rod  240  to the first carrier  21  in the art, the drawings do not provide detailed illustration. 
       FIGS. 4A and 4B  illustrate the operation of the actuating rod group  24  according to the present invention. When the active rod  240  is driven to move forward or backward, the coupling rods  241  are brought to move forward or backward together with the active rod  240 , which further brings the second side portions  20   b  of the whole row of the light collecting units  20  to swing about the corresponding first side portions  20   a , respectively, such that the whole row of the light collecting units  20  present a shutter style open/close effect. During operation, a detection actuating unit (not shown) is used to provide a drive force for operating the actuating rod group  24 . Since the detection actuating unit is well known in the art and is not considered an essential technical feature of the present invention, detailed description thereof is omitted herein. 
     Table 1 shows the elevation and azimuth of the sun at latitude 23 degrees north at different time points. If the active rod  240  of the actuating rod group  24  moves towards a direction A, the lower portion of the light collecting units  20  can swing such that the elevation of the lens assemblies  201  is adjusted to correspond to the path of the sun in a day. For example, the swing amplitude of the light collecting units  20  is configured to correspond to the path of the sun from eight in the morning to four in the afternoon on January 21 st  so as for the lens assembly  201  to face the sunlight S, thereby enhancing the light collecting efficiency of the power supply apparatus  2 . 
     Further, a position limiting rod  243  is disposed in the path of movement of the active rod  240  so as to prevent the active rod  240  from sliding away from the efficient path, as shown in  FIGS. 2B ,  4 A and  4 B. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Latitude 23 degrees North, 21 st  of Each Month 
               
            
           
           
               
               
            
               
                   
                 time 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 08:00 
                 10:00 
                 12:00 
                 14:00 
                 16:00 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 date 
                 azimuth  
                 elevation 
                 azimuth 
                 elevation 
                 azimuth 
                 elevation 
                 azimuth 
                 elevation 
                 azimuth 
                 elevation 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 January 
                 148.4 
                 17.3 
                 126.5 
                 37.9 
                 90 
                 46.9 
                 53.5 
                 37.9 
                 31.6 
                 17.3 
               
               
                 February 
                 156.4 
                 22 
                 133.8 
                 44.9 
                 90 
                 55.8 
                 46.2 
                 44.9 
                 23.6 
                 22 
               
               
                 March 
                 166.9 
                 27.2 
                 145.4 
                 52.6 
                 90 
                 55.5 
                 34.6 
                 52.6 
                 13.1 
                 27.2 
               
               
                 April 
                 179.6 
                 31.9 
                 163.3 
                 59.2 
                 90 
                 78.6 
                 16.7 
                 59.2 
                 0.4 
                 31.9 
               
               
                 May 
                 189.3 
                 34.5 
                 179.9 
                 62 
                 90 
                 87.1 
                 0.1 
                 62 
                 350.7 
                 34.5 
               
               
                 June 
                 193.2 
                 35.3 
                 187 
                 62.5 
                 270 
                 89.6 
                 353 
                 62.5 
                 346.8 
                 35.3 
               
               
                 July 
                 189.4 
                 34.5 
                 180.1 
                 62 
                 90 
                 87.2 
                 359.9 
                 62 
                 350.6 
                 34.5 
               
               
                 August 
                 179.4 
                 31.9 
                 163 
                 59.2 
                 90 
                 78.4 
                 17 
                 59.2 
                 0.6 
                 31.9 
               
               
                 September 
                 166.7 
                 27.1 
                 145.2 
                 52.5 
                 90 
                 66.4 
                 34.8 
                 52.5 
                 13.3 
                 27.1 
               
               
                 October 
                 155.6 
                 21.6 
                 143 
                 44.2 
                 90 
                 54.9 
                 47 
                 44.2 
                 24.4 
                 21.6 
               
               
                 November 
                 147.8 
                 16.9 
                 126 
                 37.3 
                 90 
                 46.2 
                 54 
                 37.3 
                 32.2 
                 16.9 
               
               
                 December 
                 145.6 
                 15.5 
                 124.2 
                 35.2 
                 90 
                 43.6 
                 55.8 
                 35.3 
                 34.4 
                 15.5 
               
               
                   
               
            
           
         
       
     
       FIGS. 5A and 5B  show the operation of the supporting rods  23   a ,  23   b . The driving force is provided by a detection actuating unit (not shown) for controlling the extension and retraction movement of the supporting rods  23   b . When the supporting rods  23   b  extends towards a direction B, the supporting rods  23   b  slide on the second carrier  22  towards a direction C, and the rear side of the second carrier  22  swings around the supporting rods  23   a  located at the front side of the second carrier  22  such that both the rear side of the second carrier  22  and the whole row of the light collecting unit  20  are lifted. On the other hand, the supporting rods  23   b  can be retracted and the position limiting rod  243  can undergo the same retraction movement as the supporting rods  23   b.    
     Further referring to  FIG. 2B , the assisting rod  242   a  is pivotally connected to the coupling rods  241 , when the second carrier  22  is lifted or lowered, the coupling rods  241  is also lifted or lowered, that is, the assisting rod  242   b  swings about the assisting rod  242   a  so as to lift or lower the rear side of the coupling rods  241  while the position of the assisting rod  242   a  and the active rod  240  remain unchanged. It should be noted that since there are various kinds of methods for slidingly disposing the supporting rods  23   b  on the second carrier  22  in the art, the drawings do not provide detailed illustration. 
     Further referring to Table 1, the supporting rods  23   b  undergo extension or retraction movement so as for the light collecting units  20  to correspond to different elevations at the same time point of different seasons, for example, an elevation of 35.3 degree at eight in the morning of June and an elevation of 17.3 degree at eight in the morning of January. As such, the elevation of the lens assemblies  201  can be adjusted (for example, α, β, α&gt;β in the drawings) to face the sunlight S so as for the power supply apparatus  2  to collect the same amount of sunlight at the same time point of different seasons. 
       FIG. 6A  shows a photovoltaic device according to the present invention, and  FIG. 6B  is an azimuth definition diagram for the sun corresponding to Table 1. As shown in  FIG. 6A , the photovoltaic device comprises: at least two power supply apparatuses  2 ,  2 ′ arranged in tandem, a track  3  corresponding to the path of the sun, and a supporting frame  4  slidingly disposed on the track  3  and connected to the power supply apparatuses  2 ,  2 ′. 
     The two power supply apparatuses  2 ,  2 ′ are the same as each other. In other embodiments, the number of the power supply apparatuses  2 ,  2 ′ can be increased as needed. The first carriers  21 ,  21 ′ have a wheel train  210  slidable and configured to move along the track  3 . The first carriers  21 ,  21 ′ further have supporting members  211  on which the wheel train  210  is disposed. 
     The track  3  is of a circular shape and is fixed in position to the ground. The track  3  can rotatably support the first carrier  21  so as to change the azimuth of the light collecting units  20  on the second carrier  22  corresponding to the path of the sun such that the sunlight falls on the lens assemblies  201  at an optimum angle. In the present embodiment, the track  3  is fixed in position to the roof, and is of a circular shape corresponding to the azimuth of  FIG. 6B . Alternatively, the track is of an irregular curved shape, a triangular shape, a rectangular shape or an elliptic shape. 
     The supporting frame  4  are of a radial shape, which has an upper end thereof fixed in position to the first carriers  21 ,  21 ′ and a lower end with the supporting members  211  slidingly disposed on the track  3  such that the power supply apparatuses  2 ,  2 ′ can slide along the track  3  so as to turn eastwards or westwards corresponding to the path of the sun of different seasons. The number of the wheel train  40  of the supporting frame  4  can be changed according to the configuration of the first carriers  21 ,  21 ′ such that the power supply apparatuses can turn direction in a balanced manner. Further, the type of the supporting frame  4  is not limited to the present embodiment. 
     In the present embodiment, the rear side of the second carrier  22 ′ of the power supply apparatus  2 ′ can be lifted or lowered by extending or retracting the supporting rods  23 ′ located at the rear side of the power supply apparatus  2 ′ so as to make the light collecting units  20 ′ of the power supply apparatus  2 ′ correspond to the height of the sun in the four seasons as shown in  FIGS. 5A and 5B . As such, the lens assembly  201 ′ of the power supply apparatus  2 ′ can absorb the needed sunlight. The prevent invention prevents the front power supply apparatus  2  from casting a shadow on part of the light collecting units  20 ′ of the rear power supply apparatus  2 ′ without increasing the distance between the power supply apparatuses  2 ,  2 ′, thereby enhancing the light collecting efficiency in all the four seasons of a year. Furthermore, the supporting rods  23  located at the front side of the power supply apparatus  2  can be adjusted as needed. 
     During operation, the detection actuating unit (not shown) controls the supporting frame  4  and the supporting rods  23 ,  23 ′ so as to adjust the direction of the power supply apparatuses  2 ,  2 ′ corresponding to the sun and adjust the relative height of the second carriers  22 ,  22 ′. 
       FIG. 7  shows another embodiment of a photovoltaic device. The photovoltaic device of the present embodiment is mostly similar to the first embodiment. The photovoltaic device of the present embodiment differs from that of the first embodiment in terms of design and operation of the supporting rods. 
     The supporting rods  53 ,  53 ′ are disposed corresponding to the configuration of the second carriers  52 ,  52 ′, with one end thereof fixed in position to the front and rear sides of the first carriers  51 ,  51 ′ and the other end thereof fixed in position to the front and rear sides of the second carriers  52 ,  52 ′ for synchronously lifting or lowering the front and rear sides of the second carriers  52 ,  52 ′. Further, the number of the supporting rods  53 ,  53 ′ can be increased or decreased as needed. 
     By adjusting the supporting rods  53 ′ at the rear side of the power supply apparatus  5 ′ so as to increase the whole height of the second carrier  52 ′ of the power supply apparatus  5 ′ and moving the active rod  240  (referring to  FIG. 2B ) backwards or forwards, the light collecting units  50 ′ of the rear power supply apparatus  5 ′ can be higher than the light collecting units  50  of the front power supply apparatus  5 . Thus, the lens assemblies  501 ′ at the rear side together with the lens assemblies  501  at the front side form a solid plane so as to collect the sunlight at dawn and dusk. 
     Further, in the present embodiment, supporting frames  4 ′ are parallel arranged. 
     In addition, corresponding to different height of the sun in different areas of different latitudes, the elevation of the device can be adjusted so as to collect required amount of light. 
     According to the present invention, the actuating rod group brings the whole row of light collecting units to swing with an amplitude corresponding to the position of the sun so as to make the lens assemblies face the sunlight, thereby enhancing the light collecting efficiency. 
     Further, the supporting rods can be adjusted to change the height of the second carrier so as to make the light collecting units correspond to the height of the sun in a year, thereby enhancing the light collecting efficiency. 
     The above-described descriptions of the detailed embodiments are intended to illustrate the preferred implementation of the present invention but are not intended to limit the scope of the present invention, Accordingly, all modifications and variations made to the embodiments by persons skilled in the art should still fall within the scope of present invention defined by the appended claims.