Solar energy system and geared drive system

Abstract

A control system for a solar energy system causes motor assemblies to pivot the photovoltaic (PV) arrays of the solar energy system about respective longitudinal axes, e.g., to track the sun across the sky. The solar energy system also has an inverter with a known inverter rating, e.g., for a given output level and ambient temperature. The control system is programmed, inter alia, to determine when a calculated electrical output of the PV arrays, e.g., a future electrical output during an imminent future time period, exceeds the inverter rating. The control system then causes some or all of the PV arrays to pivot out of regular solar tracking mode into a position that introduces higher cosine losses, so as to reduce real-time electrical output from at least the direct normal component of real-time solar irradiance incident on the PV arrays involved in order not to exceed the inverter rating, or to exceed it less.

1 . A method of operating a solar energy system, the solar energy system comprising a plurality of photovoltaic (PV) modules, respective motor assemblies configured to pivot the plurality of PV modules about respective longitudinal axes, and an inverter having an inverter rating, the method comprising:
 a. determining that a calculated electrical output of the plurality of PV modules exceeds the inverter rating; and   b. pivoting one or more PV modules of the plurality of PV modules so as to reduce real-time electrical output from at least a direct normal component of real-time solar irradiance incident on the one or more PV modules.   
     
     
         2 . The method of  claim 1 , wherein the calculated electrical output comprises future electrical output. 
     
     
         3 . The method of  claim 1 , wherein the calculated electrical output is calculated using irradiance data. 
     
     
         4 . The method of  claim 3 , additionally comprising, before the determining:
 accessing irradiance data.   
     
     
         5 . The method of  claim 4 , wherein the accessed irradiance data includes historical irradiance data. 
     
     
         6 . The method of  claim 4 , wherein the accessed irradiance data includes current irradiance data. 
     
     
         7 . The method of  claim 4 , wherein the accessed irradiance data includes forecasted irradiance data. 
     
     
         8 . The method of  claim 4 , wherein the accessed irradiance data includes at least two types of irradiance data selected from historical irradiance data, current irradiance data, and forecasted irradiance data. 
     
     
         9 . The method of  claim 1 , wherein the pivoting includes pivoting at least one of the one or more PV modules so as to reduce the direct normal component by at least 70%. 
     
     
         10 . The method of  claim 1 , wherein the pivoting includes pivoting at least one of the one or more PV modules so as to reduce the direct normal component by at least 50%. 
     
     
         11 . The method of  claim 1 , wherein the pivoting includes pivoting at least one of the one or more PV modules so as to reduce the direct normal component by at least 10%. 
     
     
         12 . The method of  claim 1 , wherein the pivoting reduces real-time electrical output of the plurality of PV modules to be not more than the inverter rating. 
     
     
         13 . The method of  claim 1 , wherein (i) the pivoting reduces the real-time electrical output of the plurality of PV modules to be more than the inverter rating, and (ii) the inverter additionally performs a clipping function. 
     
     
         14 . The method of  claim 7 , wherein the accessing includes acquiring an irradiance forecast for an imminent future time period characterized by having a length of not more than 15 minutes. 
     
     
         15 . A control system in communication with one or more motor assemblies configured to pivot, about respective longitudinal axes, a plurality of PV modules of a solar energy system, the solar energy system additionally comprising an inverter having an inverter rating, the control system comprising program code for determining that a calculated electrical output of the plurality of PV modules exceeds the inverter rating, and for causing one or more PV modules of the plurality of PV modules to pivot so as to reduce real-time electrical output from at least a direct normal component of real-time solar irradiance incident on the one or more PV modules. 
     
     
         16 . The control system of  claim 15 , wherein the program code is additionally for accessing irradiance data, and wherein the calculated electrical output is calculated using the irradiance data. 
     
     
         17 . The control system of  claim 16 , wherein the accessed irradiance data includes forecasted irradiance data of an irradiance forecast for an imminent future time period characterized by having a length of not more than 15 minutes. 
     
     
         18 . A solar energy system comprising a plurality of photovoltaic (PV) modules, respective motor assemblies configured to pivot the plurality of PV modules about respective longitudinal axes, an inverter having an inverter rating, and the control system of  claim 15 .