Power conversion systems

Abstract

In a general aspect, a power conversion system includes a power converter, a transformer, and a voltage adjustment device. The power converter is configured to receive a variable DC power generated by a power generation device and to convert the received DC power to AC power at a first voltage. The transformer is configured to receive the AC power from the power converter and to deliver AC power at a second voltage to a utility power network. The voltage adjustment device is configured to adjust the first voltage to a target value determined on the basis of a voltage of the DC power.

1 . (canceled) 
     
     
         2 . An apparatus for conversion of time-varying DC power to AC power at a specified voltage, said apparatus comprising: a power converter configured to receive DC power having a time-varying power level, said DC power being generated by a power generation device, and to convert the received DC power to AC power at a first voltage; and a voltage regulation system for adjusting said first voltage to a target value based at least in part on a voltage of said time-varying power level. 
     
     
         3 . The apparatus of  claim 2 , wherein the voltage regulation system includes a first transformer for stepping said AC power at said first voltage to a second voltage. 
     
     
         4 . The apparatus of  claim 3 , further comprising a second transformer for stepping said second voltage to a third voltage. 
     
     
         5 . The apparatus of  claim 4 , further comprising a controller for adjusting the second voltage in response to time-varying power level. 
     
     
         6 . The apparatus of  claim 3 , wherein said first transformer comprises a variable voltage transformer for generating a variable first voltage from said second voltage. 
     
     
         7 . The apparatus of  claim 4 , wherein the second transformer comprises a load tap changer. 
     
     
         8 . The apparatus of  claim 2 , wherein said voltage regulation system comprises a collector bus for receiving AC power originating from said power converter, said collector bus receiving additional AC power originating from additional power converters. 
     
     
         9 . The apparatus of  claim 8 , wherein said voltage regulator system further comprises a distribution voltage regulator on said collector bus. 
     
     
         10 . The apparatus of  claim 9 , wherein said voltage regulator comprises a load tap changer connected to a transformer. 
     
     
         11 . The apparatus of  claim 9 , further comprising a second transformer coupled to a load tap changer, said second transformer being is configured to transform said second voltage to a third voltage. 
     
     
         12 . The apparatus of  claim 2 , wherein the voltage regulation system further comprises a controller that receives information from the power converter and, based at least in part on said information, provides control signals to a load tap changer controlled by the voltage regulation system. 
     
     
         13 . The apparatus of  claim 12 , wherein said information comprises a DC voltage received by said power converter. 
     
     
         14 . The apparatus of  claim 10 , wherein said distribution voltage regulator is configured to connect to a utility grid. 
     
     
         15 . The apparatus of  claim 2 , further comprising a solar array connected to said power converter. 
     
     
         16 . An apparatus for converting variable DC power to AC at a specified voltage, said apparatus comprising: means for converting variable DC power into a first AC voltage; means for converting said first AC voltage into a target AC voltage based at least in part on said variable DC power. 
     
     
         17 . The apparatus of  claim 16 , further comprising means for providing said variable DC power to said means for converting. 
     
     
         18 . The apparatus of  claim 17 , wherein said means for providing said variable DC power comprises means for converting sunlight into electricity. 
     
     
         19 . An apparatus for providing AC to an electric utility, said apparatus comprising: a first solar array; a second solar array; a first inverter connected to said first solar array; a second inverter connected to said second solar array; a collector bus for receiving AC power originating at said first inverter and at said second inverter; and a voltage regulator for converting a first AC voltage on said collector bus to a specified second AC voltage. 
     
     
         20 . The apparatus of  claim 19 , further comprising a controller for determining said specified second AC voltage based at least in part on an output of said first and second inverter, and causing said voltage regulator to output said specified second AC voltage.