Photovoltaic System Power Tracking Method

Abstract

A photovoltaic system including a photovoltaic cell, and an electronic module connected to the photovoltaic cell. The electronic module is adapted to produce at least one control signal indicative of electrical power being generated by the photovoltaic cells. A tracking controller is adapted to receive the control signal(s) and based on the control signal(s), the controller is adapted to control a tracking motor for adjusting the system so that electrical power generated by the photovoltaic cells is increased. The photovoltaic system may include an optical element, adapted for concentrating solar light onto the photovoltaic cells. The electronic module preferably performs direct current (DC) to direct current (DC) power conversion and maximum power point tracking by electrical power, current, or voltage at either their inputs or their outputs. Alternatively, the tracking controller is configured to also perform maximum power point tracking by increasing to a local maximum electrical power by varying at least one of (i) current or voltage output from the photovoltaic cell or (ii) current or voltage output from the electronic module.

1 - 15 . (canceled) 
     
     
         16 . An apparatus comprising:
 one or more photovoltaic cells configured to produce direct-current power;   a light diffuser; and   control circuitry configured to change a distance between the light diffuser and the one or more photovoltaic cells.   
     
     
         17 . The apparatus of  claim 16 , further comprising a power converter configured to convert the direct-current power produced by the one or more photovoltaic cells. 
     
     
         18 . The apparatus of  claim 17 , wherein the power converter is configured to perform direct-current to direct-current power conversion. 
     
     
         19 . The apparatus of  claim 16 , wherein the control circuitry is configured to:
 measure the direct-current power produced by the one or more photovoltaic cells; and   increase, based on the measure of the direct-current power, the direct-current power to a local maximum by varying at least one of current and voltage output from the one or more photovoltaic cells.   
     
     
         20 . The apparatus of  claim 16 , wherein the control circuitry is configured to perform maximum power point tracking of the direct-current power produced by the one or more photovoltaic cells. 
     
     
         21 . The apparatus of  claim 20 , wherein the control circuitry is configured to perform the maximum power point tracking independent from the change in the distance between the light diffuser and the one or more photovoltaic cells. 
     
     
         22 . The apparatus of  claim 16 , further comprising an optical element configured to concentrate intensity of light onto the one or more photovoltaic cells. 
     
     
         23 . The apparatus of  claim 22 , wherein the control circuitry is configured to increase evenness of the light distributed over the one or more photovoltaic cells by defocusing the optical element. 
     
     
         24 . The apparatus of  claim 22 , wherein the control circuitry is configured to increase a number of the one or more photovoltaic cells over which the light is distributed by defocusing the optical element. 
     
     
         25 . An apparatus comprising:
 a plurality of photovoltaic cells configured to generate direct-current power;   an optical element configured to focus light onto the plurality of photovoltaic cells; and   control circuitry configured to increase a number of the plurality of photovoltaic cells over which the light is distributed by defocusing the optical element.   
     
     
         26 . The apparatus of  claim 25 , wherein the control circuitry is configured to defocus the optical element by causing a distance between the optical element and the plurality of photovoltaic cells to change. 
     
     
         27 . The apparatus of  claim 25 , wherein the control circuitry is configured to control the defocusing of the optical element such that electrical power produced by a selected subset of the plurality of photovoltaic cells is maximized. 
     
     
         28 . The apparatus of  claim 25 , further comprising a motor configured to adjust a position of the optical element, wherein the control circuitry is configured to defocus the optical element by controlling the motor. 
     
     
         29 . The apparatus of  claim 25 , wherein the control circuitry is configured to perform maximum power point tracking individually on each of the plurality of photovoltaic cells. 
     
     
         30 . A method comprising:
 combining electrical power produced by a plurality of photovoltaic cells arranged on an optical surface;   adjusting a position of the optical surface based on maximizing electrical power produced by a subset of the plurality of photovoltaic cells independently from power produced by all of the plurality of photovoltaic cells, wherein the subset of the plurality of photovoltaic cells is periodically changed to a different subset.   
     
     
         31 . The method of  claim 30 , wherein the adjusting of the position of the optical surface comprises:
 changing an angular orientation of the optical surface towards a sun.   
     
     
         32 . The method of  claim 30 , wherein the adjusting of the position of the optical surface comprises:
 adjusting a distance of the optical surface from an optical element that focuses light onto the plurality of photovoltaic cells.   
     
     
         33 . The method of  claim 30 , wherein the adjusting of the position of the optical surface comprises:
 defocusing light from an optical element onto the optical surface such that the electrical power produced by a subset of the plurality of photovoltaic cells is maximized.   
     
     
         34 . The method of  claim 30 , wherein the adjusting of the position of the optical surface comprises:
 adjusting a position of the optical surface with respect to a light diffuser that diffuses light onto the optical surface.   
     
     
         35 . The method of  claim 30 , comprising:
 performing maximum power point tracking of the plurality of photovoltaic cells by varying at least one of current and voltage output from the plurality of photovoltaic cells.