Smart renewable energy system with grid and dc source flexibility

Abstract

A method and apparatus is disclosed relating to smart renewable power generation systems with grid and DC source flexibility that can (1) intelligently and selectively pull power from one or multiple DC sources including solar panels, wind generators, and batteries based on certain criteria; (2) invert DC power to AC power; (3) supply the AC power to the electric grid or to an off-grid electric circuit to power AC loads; (4) supply DC power through one or multiple DC output ports to power DC loads; and (5) charge batteries. Various types of on-grid, off-grid, and on/off-grid DC flexible power inverters are described to demonstrate the innovation for delivering flexible, cost-effective, and user-friendly power generation systems to harvest any form of renewable energy available and convert it to usable electricity.

1 . A scalable DC to AC power inversion system for providing AC power to an electric grid from a plurality of individual DC power sources each having a DC output port, comprising:
 a) at lease one on-grid power inverter, each having an on-grid AC output port and multiple DC input ports constructed and arranged to be connected to multiple DC power sources including at least one photovoltaic solar panel, at least one wind generator, or at least one battery, or any combination thereof;   b) each power inverter being constructed and arranged to pull DC power from one or multiple DC input ports based on pre-defined DC source selection criteria;   c) the on-grid AC output port of each inverter being combined in parallel to supply AC power to the grid; and   d) whereby said system is incrementally scalable by adding or subtracting DC power sources and inverters.   
     
     
         2 . The scalable DC to AC power inversion system of  claim 1 , in which the DC source selection criteria of each on-grid power inverter comprises:
 (a) maximizing the harvest of solar and wind energy and supplying generated AC power to the electric grid;   (b) pulling power or stop pulling power from the battery based on power dispatch commands from an independent grid system operator (ISO) that manages the electric grid so the generated AC power is ramped up and down for grid stabilization; and   (c) charging battery when there is excess DC power from solar or wind.   
     
     
         3 . The scalable DC to AC power inversion system of  claim 1 , in which the output of each said power inverter is single-phase AC or three-phase AC. 
     
     
         4 . A method of making an on/off-grid DC source flexible power generation system incrementally scalable, comprising:
 a) providing a plurality of DC power sources and a plurality of on/off-grid power inverters, each having an on-grid AC output port, an off-grid AC output port, and at least one DC input port;   b) connecting DC input ports to multiple DC sources including at least one photovoltaic solar panel, at least one wind generator, or at least one battery, or any combination thereof;   c) pulling power from the connected DC sources based on pre-defined DC source selection criteria; and   d) providing AC power to an electric grid through said on-grid AC output ports when the grid is on or providing AC power to one or multiple AC loads, individually, through said off-grid AC output port of each inverter when the grid is down.   
     
     
         5 . The method of  claim 4 , further comprising:
 a) each of said inverters having an on-grid AC input port;   b) combining said on-grid AC output port of all inverters together by daisy-chaining the inverters, said on-grid AC output port of each inverter being connected in a daisy chain to the on-grid AC input port of the next inverter, except for the on-grid AC output port of the first inverter being connected to the electric grid, and the on-grid AC input port of the last inverter being left open; and   c) providing AC power to the electric grid through the on-grid AC output port of the first inverter when the grid is on.   
     
     
         6 . The method of  claim 4 , further comprising:
 a) combining said off-grid AC output port of all inverters together so the total produced AC power is the summation of the AC power supplied by each inverter; and   b) providing AC power to one or multiple AC loads through the combined off-grid AC output ports when the grid is down.   
     
     
         7 . The method of  claim 4 , in which the DC source selection criteria comprises:
 (a) maximizing the harvest of solar and wind energy and supplying generated AC power to an electric grid when the grid is on;   (b) providing sufficient AC power to run the connected AC loads without using battery power when the grid is down;   (c) pulling power from battery to meet the power demand when solar and wind cannot produce sufficient DC power for the system to run the connected AC loads; and   (d) charging battery when there is excess DC power from solar or wind.   
     
     
         8 . The method of  claim 4 , in which the DC source selection criteria further comprises pulling power or stop pulling power from the battery based on power dispatch commands from an independent grid system operator (ISO) that manages the electric grid so the generated AC power is ramped up and down for grid stabilization when grid is on. 
     
     
         9 . The method of  claim 4 , in which the output of each said power inverter is single-phase AC or three-phase AC. 
     
     
         10 . The method of  claim 4 , further comprising:
 a) connecting a first DC power source to one of said DC power input ports of one of said power inverters; and   b) connecting a second DC power source, different in kind from said first DC power source, to another of said DC power input ports of said one power inverter.