IL302523A - Optical solar tracking system - Google Patents

Description

Docket 231-005 April 24, 20 - 1 - OPTICALLY ENHANCED SOLAR RADIATION TRACKER TECHNOLOGY FIELD id="p-1"

[001] The present disclosure relates to the field of solar photovoltaic (PV) systems improvement and particularly to performance improvement of the solar systems based on bifacial photovoltaic panels mounted on sun trackers.

BACKGROUND id="p-2"

[002] Solar PV panels are usually stationary panels. At a particular time of the day, when the incident sun rays are perpendicular to the solar panel surface, the panels have maximum efficiency. Solar tracking systems enhance solar panel performance. The solar tracker positions the solar photovoltaic panel surface perpendicular to the Sun's rays. The tracking systems start following the Sun in the morning and return the solar photovoltaic panel to the initial state for the next morning. [003] Solar tracking systems optimize land use and generate more electricity than the installations with static solar panels, and occupy almost the same amount of land. Some tracking systems operate according to the daytime, and some use built-in sensors to measure the actual incident solar radiation. Such systems provide the corresponding signal to the tracker controller, which commands the trackers' driver to rotate the panel to an angle, which provides the maximal energy yield of the photovoltaic (PV) panel. [004] Photovoltaic (PV) panels are mounted above the ground on poles. Tracking solar panels are typically installed in large clusters with several meters of distance between rows of panels. The gaps between the solar panels provide sufficient space to avoid or minimize obstruction of solar panels by adjacent solar panels during sun tracking. [005] US patent applications US 20170353145A1 and US 20200119686Adescribe the use of additional side mirrors to enhance the output of a solar photovoltaic system. US 20170353145A1 reflects the sunlight to the front side of Docket 231-005 April 24, 20 - 2 - a single-facial solar panel. US 20200119686A1 in sun tracking changes the angle between the additional stationary reflector and the rotated PV panel.

DEFINITIONS id="p-6"

[006] Primarily used single-axis solar tracking systems follow the Sun by rotating the solar panel on the axis, usually parallel to a South-North direction. [007] Dual-axis solar tracking systems panels rotate the solar panel on two axes simultaneously or sequentially. The dual-axis trackers align the solar panel with the Sun horizontally and vertically. [008] Agri photovoltaic systems (Agri-PV) facilitate land use for agriculture and energy production by utilizing the land space between solar PV rows for agricultural purposes. [009] Solar backtracking is a tracking control program that aims to minimize PV panel-on-panel shading, thus avoiding electricity production losses. When a tracker, or a linked tracker row, is used near another, it shades the adjacent tracker during early morning and late afternoon hours. The backtracking algorithm is implemented to drive the solar panels' position during these periods. [0010] HJT - means Hetero-Junction solar cell and panel. TOPCon – is an abbreviation of 'Tunnel Oxide Passivated Contact' solar PV cell and panel [0011] HJT and TOPCon technologies provide the best available bifaciality of 85%-95%, meaning that the back side of a bifacial PV panel ensures almost the same efficiency as the front side.

SUMMARY id="p-12"

[0012] A solar photovoltaic system includes one or several bifacial solar modules or panels, each with front and back sides. The bifacial photovoltaic module is mounted on a solar tracking mechanism. The system includes one or more mirrors located aside from the photovoltaic module and behind the backside of the photovoltaic module. The front side of the bifacial photovoltaic module and the Docket 231-005 April 24, 20 - 3 - mirror receive direct sunlight. The mirror reflects the received sun radiation to the backside of the photovoltaic module. The mirrors provide uniform radiation of the photovoltaic module's backside. The front and the backside of the bifacial photovoltaic module generate electricity. [0013] The system is configured to minimize shading between the adjacent solar photovoltaic panels. Several sensors mounted at the edges of the mirrors provide shading feedback for controlling the photovoltaic panel backtracking.

LIST OF DRAWINGS AND THEIR SHORT EXPLANATION id="p-14"

[0014] In the drawings which show non-limiting examples of the method and apparatus: [0015] FIG. 1 is an illustration of a typical tracking solar panels installation; [0016] FIG. 2A is an example of additional solar radiation reflectors mounted behind and along a side of a bifacial solar panel; [0017] FIG. 2B is an example of a single additional solar radiation reflector mounted behind and along a side of a bifacial solar panel; [0018] FIG. 3 is an example of additional solar radiation reflectors parameters; [0019] FIG. 4 is an example of additional solar radiation reflectors configured to alleviate the shading of the bifacial solar panel mount; [0020] FIG. 5 is an example of additional solar radiation reflectors configured to either avoid shading or alleviate the increased wind load on the bifacial solar panel and tracker mount; [0021] FIG. 6 is another example of rotating additional solar radiation reflectors to illuminate the bifacial solar panel back side; [0022] FIG. 7 is an example illustrating a combined rotation of a bifacial solar panel and a single mirror in the morning hours; and [0023] FIG. 8 is another example illustrating a combined rotation of a bifacial solar panel and a single mirror in the late afternoon hours.

Docket 231-005 April 24, 20 - 4 - DESCRIPTION id="p-24"

[0024] The present disclosure will be described by way of example with reference to the accompanying drawings, in which the same reference numeral is for the common elements in the various figures. Accordingly, the description and the drawings should be regarded in an illustrative sense rather than a restrictive one. [0025] Tracking solar panels are typically installed in large clusters with several meters of distance between rows of neighbor solar panels. The gaps (S) between the solar panels 104 provide sufficient space for the unobstructed solar panel 1rotation needed for sun tracking. FIG. 1 is an illustration of a typical tracking solar panels installation. In the figure: L - is the size or dimension of the solar panel, and D – is the distance between the supports of the neighbor solar panels. [0026] Typically, the solar panel area covering ratio is defined by D/L = 2.5, meaning that the sunlight collecting area of PV panels is about 40% of the used land area. In comparison, the unused area ratio is 60%, meaning that much of the solar radiation resource is not collected. [0027] The present disclosure suggests an increase in the covering ratio by using additional solar radiation reflectors mounted behind and along the side of the bifacial solar panel to capture the solar radiation in the gap between the solar panels. The additional solar radiation reflectors could be mirrors connected to the solar tracker mechanism or driven by a dedicated solar tracker. The mirrors reflect the solar radiation to illuminate the back side of the bifacial solar panel. [0028] FIG. 1 illustrates a bifacial solar panel cluster 100 during hours around noon time when the solar panel or module 104 is about a horizontal position, and no shading exists. A pillar 108 or support stand provides support for solar panels 104. Each solar panel or module 104 has a front side 120 and a back or rear side 124. Each of the solar panels or module 104 is mounted on a solar tracking mechanism (not shown). The mounting of the solar panel 104 supports the Docket 231-005 April 24, 20 - 5 - rotation of solar panel 104 around an axis, which is parallel to the South-North direction, as shown respectively by arrow 116. The rotation of the solar panel keeps the front side 120 of the solar panel 104 perpendicular to the direct sunlight during the daytime. [0029] FIG. 2A is an example of a solar photovoltaic system 200, including photovoltaic tracking systems 202 with additional solar radiation reflectors mounted behind and along a side of a bifacial solar panel. At least one and typically two additional solar radiation reflectors 204 mounted behind and along a side of the bifacial solar panel 212, which has front side 212a and backside 212b. The additional solar radiation reflectors, or mirrors 204, are mechanically connected to the tracker (not shown) and rotate with the bifacial solar panel 212. The additional solar radiation reflectors 204 or backside mirrors are located symmetrically behind and along both sides of the PV module. The backside mirrors are configured to collect and direct incident solar radiation 216 falling within aperture 208 to half of the back side 212b of the bifacial solar panel 212. The directed incident solar radiation 216 uniformly illuminates half of the back side 212b of the bifacial solar panel 212. The described system keeps the plane of the backside mirror 204 oriented at a constant tilt angle relative to the back side 212b plane of the photovoltaic module 212. [0030] The solar photovoltaic system 200 includes one or more adjacent bifacial photovoltaic modules 212. Each photovoltaic module 212 has a front side 212a and backside 212b mounted on a solar tracking mechanism, and at least one backside mirror 204 located along the photovoltaic module 212 and behind its back side 212b. The front side 212a of the bifacial photovoltaic module 212 and the mirror 204 primarily receive direct sun radiation or sunlight 216. The back side 212b of the bifacial photovoltaic module 212 primarily receives diffuse sun radiation or sunlight, and the sunlight reflected from backside mirrors 204. The periodic distance between the multiple photovoltaic panels or systems is D. [0031] FIG. 2B is an example of a single additional solar radiation reflector mounted behind and along a side of a bifacial solar panel. The single additional Docket 231-005 April 24, 20 - 6 - solar radiation reflector or mirror 224 collects solar radiation 216 captured by aperture 228 of the single additional solar radiation reflector 224. Solar radiation reflector or mirror 224 directs the captured incident solar radiation 216 and uniformly illuminates the whole back side 212b of the bifacial solar panel or photovoltaic module 212. The single additional solar radiation reflector 224 is located aside the photovoltaic module 212 and behind its back side 212b. [0032] Both of the solutions presented in FIGS. 2A and 2B enhance the electric output of the bifacial solar panel 212. The front 212a and back 212b sides of the bifacial solar panel 212 generate electricity (photocurrent) simultaneously. [0033] FIG. 3 is an example of additional solar radiation reflector parameters. In the figure: [0034] H – is the distance between the solar panel plane and the lower edge of the additional solar radiation reflector; [0035] W – is the minimum width of the additional solar radiation reflector facilitating uniform illumination of the panel backside; [0036] X – the width of the aperture from which the additional solar radiation reflector collects the solar radiation; [0037] G – is the gain caused by the collection of solar radiation by the additional solar radiation reflector relative to the solar radiation collection by the front side of the solar photovoltaic (PV) panel only; [0038] ß – is the inclination or tilt angle of the additional solar radiation reflectors relative to the photovoltaic panel plane; [0039] The listed above parameters L, X, H, W, and β are interrelated. Only an optimal combination of L, W, and H supports maximal utilization of the additional solar radiation reflectors or mirrors 304 width W (the maximal utilization means using a minimal possible mirror size for reaching minimal system cost) and uniform solar radiation illumination of the half (L/2) of the bifacial solar panel 308 backside 312 (or of the whole back side of the bifacial solar panel as in the case shown on FIG 2B). In practice, the mirror's actual width Docket 231-005 April 24, 20 - 7 - could be a few centimeters larger than the minimal mirror size to compensate for mechanical tolerances in the whole system. [0040] In the configuration shown in FIG 2A, the optimal L, W, H combination and the inclination or tilt angle β determine the additional solar radiation collection by the half of backside 312 of the bifacial solar panel 308. [0041] The expressions or formulas below define the angle ß, which is the optimal angle between the plane of the solar panel and the plane of the additional solar radiation reflectors: β = 0.5*arctan(L/2H) W=H*tan2β/(cosβ+sin β*tan2β) X = W∙cosβ The solar radiation collection gain G is defined by the ratio of the dimensions of the solar panel L and the dimensions of the aperture X where the additional solar radiation reflectors collect the solar radiation and is equal to 2X/L. [0042] A practical example of a bifacial solar panel and the calculations given below illustrate the gain. Example: Bifacial solar panel length L=2.2m, The distance between the solar panel plane and the lower edge of the additional solar radiation reflector H=0.6m; The inclination angle of the additional solar radiation reflectors β = 31°; The width of the additional solar radiation reflector W=0.6m; The gap width from which the additional solar radiation reflector collects the solar radiation X=0.5m. [0043] In this particular case, the additional solar radiation collection surface defines the resulting maximal (theoretical) collection gain is 46%. [0044] The actual bifacial solar panel collection gain could be somehow different: Assuming the reflection coefficient of the additional solar radiation reflectors Rmirror = 90%; Docket 231-005 April 24, 20 - 8 - The angle of incidence of the reflected light to the back side of the PV panel AOI = 28°; Glass reflection coefficient Rglass = 4% (no anti-reflection coating (ARC)); The bifaciality of the bifacial solar panel is equal to 85%. [0045] The actual solar radiation energy gain G = 48%*0.9*(1-0.04)*0.85 = 34% for a complete daytime. [0046] If the additional solar radiation reflectors operate through partial daytime (in order to avoid shading from the adjacent panels and mirrors), the actual solar radiation collection gain would be 20%-25%. [0047] Actual collection gain mainly depends on the solar panel bi-facility. For a solar panel assembled by HJT cells, it may be about 90%, and for TOPCon cells, it is usually 85%. Mirrors 204 and 224 reflectances could be up to 99% depending on the mirror material, but practically it is about 90%-95% for high-quality mirrors. If there is an anti-reflection coating (ARC) on the back side of the bifacial solar panel, the actual gain will be higher since the glass reflection coefficient Rglass with the ARC is lower: 0.5%-1%. [0048] Although the use of additional solar radiation reflectors 308 (FIG. 3) is beneficial and allows an increase in solar radiation collection on all photovoltaic panels in the row of trackers at the daytime around noon, at early and late hours of the day (at large tracking angles) partial shading of the additional solar radiation reflectors could present. The additional solar radiation reflectors 304 could cause undesired shading of the adjacent photovoltaic panels. [0049] Several remedies could be to the deficiencies described above of the additional solar radiation reflectors 304. [0050] The shadowing of the solar panels 308 from adjacent trackers reduces the solar panel electricity generating effectiveness. FIG. 4 illustrates the shadowing 408 of the solar panels 308 and mirrors 410 from adjacent trackers. Some solutions exist to reduce the shadowing at large tracking angles (morning and late afternoon). Such solutions typically use an algorithm of so-called "backtracking." Docket 231-005 April 24, 20 - 9 - One or more dedicated solar radiation sensors 404 mounted on the solar tracker edge (e.g. solar panel 308 edges or mirror 410 edges) provide feedback to the tracker controller that positions the solar panel 308 at angles different from those supporting the incident solar radiation perpendicularly to the solar panel 308. Such a solution reduces the collected direct solar radiation, although the yield reduction is smaller than losses due to partial shading. Reference numeral 4marks the incident solar radiation. [0051] The solar panels shading in installations with multiple rows of solar trackers limits the maximal possible covering ratio of the solar panels. The photovoltaic system with optional backtracking sensors minimizes the shading of adjacent solar panel rows. It provides a foundation for controlling the ground shading and the shading of adjacent solar panel rows. The method does not require the use of additional moving and controlled mechanisms. [0052] FIG. 5 is an example of additional solar radiation reflectors configured to alleviate shading at large tracking angles and the increased wind load on the bifacial solar panel mount. The additional solar radiation reflectors 504 could be made foldable i., e., rotated by an independent rotation mechanism (not shown) around an axis or pivot 508, which usually coincides with the bottom edge of the mirror 504. [0053] The independent rotating mechanism supports keeping the mirrors 5optimal tilt angle β and folding them to be normal to the panel 308, or to another orientation that will minimize shading, for reducing its shading from the adjacent photovoltaic modules at large tracking angles α. Arrow 520 marks the East-West direction. [0054] Accordingly, a solar photovoltaic system includes at least one bifacial photovoltaic module or panel 308 having front side 512 and backside 312, mounted on a solar tracking mechanism, and a backside mirror 504 mounted on a rotation mechanism or pivot 508 at each side of the photovoltaic module 308 and behind the photovoltaic module. The front side 512 of the bifacial photovoltaic module 308 and the mirror 504 receive primarily direct sunlight, and the back side Docket 231-005 April 24, 20 - 10 - 312 of the photovoltaic module receives diffuse sunlight or radiation, and the sunlight reflected from the mirror 504. The mirror 504 is oriented at a tilt angle relative to the backside 312 plane of the photovoltaic module 308. The photovoltaic module 308 and the rotation of the mirror 504 are connected mechanically and rotated by the tracker simultaneously. [0055] The rotation around axis 508 could position the surface of the mirrors 5perpendicular to the bifacial solar panel 308 plane. Mirrors 504 perpendicular to the bifacial solar panel plane don't create a shadow on adjacent solar panels. [0056] Mirror folding may be triggered by a signal from the backtracking sensor mounted on the mirror edge. Folding the mirrors may also reduce wind resistance during morning and afternoon hours. [0057] At noon hours or in case of storms, when the tracker locates the panel in a horizontal position (stow) to minimize the resistance to horizontal winds, it is possible to rotate the mirrors to horizontal position 510. The rotation may not be required if the tilt angle vs. the horizontal position is relatively low and the added wind load is small. [0058] The disclosed solution does not increase the solar system's ground footprint. The solution also does not affect the balance of the system (BOS), since no additional cabling, invertors, anchoring to the ground, etc., is required. [0059] The suggested solution could also be used to retrofit the existing solar tracking system since it uses the existing BOS. This solution is especially beneficial for infrastructural photovoltaic systems like solar fences along railways, and highways, usually installed as single rows, or for agricultural (Agri-PV) sparse photovoltaic system fields with large space between the rows. [0060] The photovoltaic system with optional backtracking sensors and/or optional mirror folding mechanism minimizes the shading of adjacent solar panel rows and provides a foundation for the control of the ground shading and the shading of adjacent solar panel rows. [0061] FIG. 6 is another example of rotating additional solar radiation reflectors to illuminate bifacial solar panels' back side. A kinematically connected to the Docket 231-005 April 24, 20 - 11 - solar tracker, a single rotating additional solar radiation reflector or mirror 6rotates simultaneously with the bifacial solar panel 612, either independently or by using the existing tracking mechanism with an additional transfer gear (not shown). The single rotating mirror 604 collects solar radiation from a relatively large aperture X - 616. The kinematic connection facilitates keeping the angle of incidence on the mirror as half of the panel tracking angle. The mirror 604 with the rotating mechanism is mounted on the ground as low as possible. Such mirror mounting reduces the wind load. Reference numeral 620 marks the incident solar radiation. The solar panels' backside receives the light reflected from the Western and Eastern mirrors located from both sides of the solar panel during the morning and afternoon hours, respectively. [0062] FIG. 7 is an example illustrating a combined rotation of a bifacial solar panel and a single mirror in the morning hours. Considering the aforementioned interrelated parameters W, L, D, H, h, X and the inclination or tilt angle β of the additional solar radiation reflector becomes a function of α - the inclination or tilt angle of the bifacial solar panel 712. Reference numeral 716 marks the aperture through which mirror 720 collects additional solar radiation. The maximal (theoretical) solar radiation collection gain in this example is equal to X/L. [0063] FIG. 8 is an additional example illustrating a combined rotation of a bifacial solar panel and a single mirror in the afternoon hours. The system configuration is symmetrical to that shown in FIG. 7. [0064] Solar radiation collection aperture is X=W*cos(β). [0065] Tan(2β-α) = (D/2) / H - where α = αmax for the case that panel tilt begins shading the additional solar radiation reflectors or mirror. [0066] The distance between the rotation axes of the solar panel and the reflector H = Tan (90°-2β+α) * (w/2)/cos(β) + Sin(90°-2β+α) * (L/2)/cos(90°-2β+2α). [0067] The advantages of using independent additional solar radiation reflectors or mirrors with bifacial solar panels are reduced shading and wind resistance. [0068] An independent additional solar radiation reflector can retrofit the existing bifacial solar panel installations. The additional solar radiation reflectors or Docket 231-005 April 24, 20 - 12 - mirrors are independent and not attached to the bifacial solar panels and may avoid solar panels shading at any time of the day. In the context of the present disclosure, the term independent means that the mirror tilt may differ from the solar panel tilt at any time. The mirrors located close to the ground do not cause additional wind load on the solar panel tracker. [0069] The backtracking method utilizing backtracking sensors on the edges of the photovoltaic panels (not shown) may be applied to the panels at early and late hours of the day by decoupling between the solar panel and mirror tilt angles. The decoupling between the Sun tracking of the solar panel and rotation of the mirror enables optimization of the solar panel and mirror tilt angles, thus achieving an additional gain of the solar panel output of 5% to 6%. Due to the large vertical distance H between the panel and the mirror, the additional solar radiation reflector or mirror tilt angles are small, and solar radiation incidence angles are close to normal. [0070] Solar panel 712 collects radiation from the front side at normal incidence and from the back side at an angle of 2*("beta"- "alpha"). Using an independent rotation mechanism to tilt the solar panel 712 on an angle "alpha" can be optimized to get maximum energy yield at both the front and back panel sides and to keep the solar panel 712 surface normal to the sun rays. In the case of small angle "alpha" deviations, the main impact will be for rays reflected by the mirror 720, and therefore a better yield will be achieved. This is due to the fact that near the normal incidence, the impact of cosine "alpha" change is negligible. Therefore, the system supports the use of "alpha" angle tilt optimization and maintains the sun rays normal incidence to get the maximal overall radiation collection from both the front and back sides. [0071] Although the present disclosure has been described with reference to certain examples thereof, in view of numerous changes and variations that will be apparent to persons skilled in the art, the scope of the present disclosure is to be considered limited solely by the appended claims.

Claims (20)

1.Docket 231-005 April 24, 20 - 13 - We claim: 1. A solar photovoltaic system comprising at least one bifacial photovoltaic module having a front side and backside mounted on a solar tracking mechanism, and at least one mirror located aside the photovoltaic module and behind its back side, wherein i. the front side of the bifacial photovoltaic module and the mirror receive primarily direct sun radiation, ii. the backside of the photovoltaic module receives the diffuse solar radiation and the solar radiation reflected from the mirror and iii. wherein the plane of the at least one mirror is oriented at a constant tilt angle relative to the back side plane of the PV module.

2. The solar photovoltaic system, according to claim 1, wherein the system includes one mirror located aside from one side of the photovoltaic module.

3. The solar photovoltaic system, according to claim 1, wherein two mirrors are located symmetrically aside both sides of the photovoltaic module.

4. The solar photovoltaic system, according to claims 2 and 3, wherein in order to provide uniform illumination of the back side of the photovoltaic module, the mirror minimal size W, tilt angle β, vertical distance H between the centers of the mirror and the photovoltaic module, and the photovoltaic module size L are bound by the formulas: where n = 1 for one mirror, n=2 for two mirrors.

5. The solar photovoltaic system comprising an arrangement of multiple adjacent photovoltaic systems, according to claim 1. 6. The solar photovoltaic system, according to claim 5, wherein each system, according claim 1, comprises at least one sensor mounted at the edge of the at least one mirror for controlling the backtracking. β = 0.5*arctan(L/n*H) W=H*tan2β/(cosβ+sin β*tan2β)

6.Docket 231-005 April 24, 20 - 14 -

7. The solar photovoltaic system, according to claim 5, wherein the at least one mirror is mounted on a rotation mechanism with a pivot parallel and close to the lowest edge of the at least one mirror.

8. The solar photovoltaic system, according to claim 5, wherein the mirror mounted on a rotation mechanism facilitates the mirror positioning in one of the following positions: tilt angle β, a normal to the photovoltaic module plane, and in a horizontal position.

9. A solar photovoltaic system comprising: a. at least one bifacial photovoltaic module having a front side and back side mounted on a solar tracking mechanism and a mirror mounted on a rotation mechanism at each side of the photovoltaic module and behind its back side, wherein i. the front side of the bifacial photovoltaic module and the mirror receive primarily direct sunlight, ii. the back side of said photovoltaic module receives the diffuse sunlight and the sunlight reflected from said mirror; and iii. the plane of the at least one mirror is oriented at a tilt angle relative to the back side plane of the photovoltaic module; and iv. the solar tracking by the photovoltaic module and rotation of the mirror are synchronized.

10. The solar photovoltaic system, according to claim 9, wherein the Western and the Eastern mirrors aside the photovoltaic module reflect the direct sunlight to the back side of the photovoltaic module before and after noon, respectively.

11. The solar photovoltaic system, according to claim 9, wherein, in order to reduce the wind load, the mirror rotating mechanism with the mirror is mounted on the ground as low as possible.

12. The solar photovoltaic system, according to claim 9, wherein to ensure uniform illumination of the photovoltaic module's backside, the mirror size W, PV module tilt angle α and mirror tilt angle β, horizontal distance C and Docket 231-005 April 24, 20 - 15 - vertical distance H between the centers of the mirror and PV module size L are bound by the formulas:

13. The solar photovoltaic system, according to claim 9, wherein rotating the mirrors is driven by the solar tracking mechanism with a kinematical connection having a pre-defined transmission ratio.

14. The solar photovoltaic system comprising an arrangement of multiple photovoltaic systems, according to claim 9, located at a distance D between each other, wherein the horizontal distance between the centers of the adjacent mirrors and the photovoltaic modules is equal to D/2.

15. The solar photovoltaic system, according to claim 14, wherein the mirror reflects the direct sunlight to the back sides of adjacent Eastern and Western photovoltaic modules before and after noon, respectively.

16. The solar photovoltaic system, according to claim 14, wherein rotation of the mirrors is driven by an independent rotating mechanism enabling optimization of the mirror tilt angle β for reducing shading of photovoltaic modules from the adjacent photovoltaic modules at large tracking angles α.

17. The solar photovoltaic system, according to claim 16, wherein an independent rotating mechanism rotates the mirrors and wherein the independent rotating mechanism is driven by feedback from backtracking sensors that are located at the edges of the panel.

18. The solar PV system, according to claim 16, wherein a panel tilt angle "alpha" is optimized to get maximum energy yield at both the front and back panel sides

19. The solar photovoltaic system, according to claim 16, wherein facilitating optimization of the mirror tilt angle β reduces the photovoltaic panel shading from the adjacent photovoltaic panels at large tracking angles α. β = 0.5*(arctan(C/H) + α) H = tan(90°-2β+α)*(W/2)/cos(β)+Sin(90°-2β+α)*(L/2)/cos(90°-2β+2α) Docket 231-005 April 24, 20 - 16 -

20. A solar photovoltaic system, according to claim 14, wherein each system comprises at least one sensor mounted at the end of the photovoltaic panel for controlling the backtracking to extend the daytime sun exposure on the reflector.