Patent Publication Number: US-2023145414-A1

Title: System, method and apparatus for providing a solar pump system for use within a mechanized irrigation system

Description:
RELATED APPLICATIONS 
     The present application is a Continuation-In-Part of U.S. Pat. Application No. 17/110,577 filed Dec. 3, 2020, which further claims priority to U.S. Provisional Application No. 62/947,040 filed Dec. 12, 2019. Further, the present application incorporates by reference U.S. publications US2021360847A1 and US2021331135A1 in their entirety herein. 
    
    
     FIELD AND BACKGROUND OF THE PRESENT INVENTION 
     Field of the Present Invention 
     The present invention relates generally to a system, method and apparatus for irrigation management. More specifically, the present invention relates to a system, method and apparatus for providing a solar pump system within a mechanized irrigation system. 
     Background of the Invention 
     Modern irrigation systems consume significant amounts of electrical power. Much of this power demand goes to pumping water throughout the system and creating pressures high enough for irrigation. Usually, this power demand is met with power from the local electrical grid, or if grid power is not available, from a fossil-fueled engine-genset. Grid power, however, comes at an increasingly high cost to the operator, and engine-gensets create air pollution, and require deliveries of fuel as well as regular service and maintenance. 
     To mitigate these costs, operators have started to use solar power in their fields. Solar power is initially very expensive to use, but over time the adoption of solar power can return significant benefits. For irrigation, these benefits come with several important limitations. First, there is a limit to the power a single solar array can create. Once that limit is reached, the operator must either invest in additional panels or pay for power off the grid or from some other source. Additionally, irrigation uses significant amounts of power within short windows of time. This high level of use often extends beyond the power production capabilities of a conventional solar power system. 
     Additionally, weather greatly impacts the reliability and power generation levels of solar power systems. Still further, no matter how large, solar power systems do not generate power at night. For each of these reasons, the benefits of using a solar power system for irrigation are limited. 
     In order to overcome the limitations of the prior art, a system is needed which is able to unlock the benefits of solar power generation to maximize the operational effectiveness of modern irrigation equipment. 
     SUMMARY OF THE PRESENT INVENTION 
     To address the shortcomings presented in the prior art, the present invention provides a solar power system for use with a mechanized irrigation system. According to a first preferred embodiment, the solar power system of the present invention includes solar panels which produce DC current. This electrical power is used to power the irrigation system and to pump water into an elevated storage tank. The system of the present invention preferably uses the water stored in the elevated storage tank to provide pressurized water to the irrigation system. The system preferably converts the power from the solar panels to AC current and then uses the AC current to power the movement of the irrigation system and other sub-systems. At the same time, the system preferably uses the stored, pressurized water for irrigation. 
     According to a further preferred embodiment, the solar panels of the present invention preferably provide DC current to a charge controller, which executes power point tracking calculations to maximize the power extraction by the solar panels based on received current and voltage data. The charge controller may preferably increase the load applied to the solar panels based on the power point tracking calculations. 
     The system of the present invention preferably also includes a battery system for storing excess energy. During times when the solar array produces excess power, that electrical power may be stored in batteries or in other storage media, such as pressurized water, pressurized air, thermal storage, chemical storage (hydrogen/oxygen), mechanical storage (weight and pulley system) and the like. Then, during times when the solar array is unable to produce sufficient power required for operation of the irrigation system and/or pumps, the batteries may be used to provide the necessary supplementary power. As discussed further herein, the present invention may store energy in a variety other forms beyond pumped water storage and conventional batteries. For example, the present invention may include storing energy in storage devices including: liquid flow batteries, liquid metal batteries, sodium-sulfur (NaS) batteries, lithium batteries, lithium-sulfur batteries, alkali-metal batteries, sodium-nickel chloride batteries, thermal batteries and the like without limitation. Compressed air and thermal storage are also options. 
     According to a further preferred embodiment, the pressurized water used for irrigation may also be used for electricity generation to power the irrigation machine. A preferable way of doing this may include having a given water storage tank at a higher elevation than needed to provide sufficient water pressure for irrigation. The excess pressure could then be used to generate electricity via a water turbine. The turbine would be hydraulically located between the elevated tank and the irrigation machine. As the high pressure water flowed from the tank the pressure would be reduced by the turbine to generate electricity. The exit pressure from the turbine would be sufficient for irrigation. 
     Further, the system of the present invention also preferably includes an inverter which converts DC current received from either the solar array or battery bank (if present) to AC current. The inverter may also convert AC current received from an outside source (i.e., the grid, an engine-powered generator or the like) to DC and direct the DC current to a battery for storage or to the irrigation drive system/ well pump motor. Additionally, the system may be configured to allow the pivot (which commonly uses AC power) to use DC power. Furthermore, the pump motors could be DC or AC. According to a preferred embodiment, the entire irrigation system may include only DC powered elements and subsystems. 
     According to a further preferred embodiment, the system of the present invention preferably further includes a system switchboard and a system controller. The system switchboard preferably controls the transmission of AC current to an irrigation drive system and a given pump system. Such pump systems may include: well pump systems; boost pump systems for lower pressure pipelines; surface water pump systems; and any pump that pulls water from any source suitable for irrigation (e.g., such as wells, rivers, lakes, holding ponds, canals, etc.). The system controller preferably receives data which may include data such as: solar power production data, storage tank level data (% of full capacity), anticipated water demand data and the like. The system controller may preferably further direct the operation of the well pump to pump water through a water supply pipe to a water storage tank based at least in part on received solar power production data. 
     The system of the present invention preferably allows the irrigation system to be substantially powered using only off-grid power generated by the solar panels of the system. The system of the present invention preferably also may include multiple smaller pumps and multiple elevated water storage tanks to gravity feed the irrigation system and to produce the pressure required for water distribution. 
     Although the present invention is discussed primarily with respect to irrigation systems, the present invention is designed for use with a variety of other systems which benefit from stored power such as other agricultural applications like grain dryers, sorters, nitrogen generation/fertigation systems, and other pre- and post-harvest implements without limitation. 
     The accompanying drawings, which are incorporated in and constitute part of the specification, illustrate various embodiments of the present invention and together with the description, serve to explain the principles of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows an exemplary irrigation system in accordance with a first preferred embodiment of the present invention. 
         FIG.  2 A  shows a high level, overhead view of an exemplary irrigation field incorporating aspects of the present invention. 
         FIG.  2 B  shows an enlarged overhead view of the exemplary nitrogen generation/fertigation unit shown in  FIG.  2 A  in accordance with the present invention. 
         FIG.  3    is a block diagram illustrating an exemplary electrical and control system in accordance with the present invention. 
         FIG.  4    is a block diagram of an exemplary control device in according with a first preferred embodiment of the present invention. 
         FIG.  5    is a block diagram illustrating an alternative exemplary method for managing an irrigation system in accordance with the present invention. 
         FIG.  6    is a block diagram illustrating an alternative exemplary method for managing an irrigation system in accordance with the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Aspects of the present invention will be explained with reference to exemplary embodiments and examples which are illustrated in the accompanying drawings. These descriptions, embodiments and figures are not to be taken as limiting the scope of the claims. Further, the word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Accordingly, any embodiment described herein as “exemplary” is not to be construed as preferred over other embodiments. Additionally, well-known elements of the embodiments will not be described in detail or will be omitted so as not to obscure relevant details. 
     Where the specification describes advantages of an embodiment or limitations of other prior art, the applicant does not intend to disclaim or disavow any potential embodiments covered by the appended claims unless the applicant specifically states that it is “hereby disclaiming or disavowing” potential claim scope. Likewise, the term “embodiments” does not require that all embodiments of the invention include any discussed feature or advantage, nor that it does not incorporate aspects of the prior art which are sub-optimal or disadvantageous. 
     As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Additionally, the word “may” is used in a permissive sense (i.e., meaning “having the potential to’), rather than the mandatory sense (i.e. meaning “must”). Further, it should also be understood that throughout this disclosure, unless logically required to be otherwise, where a process or method is shown or described, the steps of the method may be performed in any order (i.e. repetitively, iteratively or simultaneously) and selected steps may be omitted. It will be further understood that the terms “comprises”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     The terms “program,” “computer program,” “software application,” “module” and the like as used herein, are defined as a sequence of instructions designed for execution on a computer system. A program, computer program, module or software application may include a subroutine, a function, a procedure, an object implementation, an executable application, an applet, a servlet, a source code, an object code, a shared library, a dynamic load library and/or other sequence of instructions designed for execution on a computer system. A data storage means, as defined herein, includes many different types of computer readable media that allow a computer to read data therefrom and that maintain the data stored for the computer to be able to read the data again. 
     Aspects of the systems and methods described herein may be implemented as functionality programmed into any of a variety of circuitry, including programmable logic devices, microcontrollers with memory, embedded microprocessors, firmware, software, etc. Furthermore, aspects of the systems and methods may be embodied in microprocessors having software-based circuit emulation, discrete logic (sequential and combinatorial), custom devices, fuzzy (neutral network) logic, quantum devices, and hybrids of any of the above device types. 
       FIGS.  1 - 4    illustrate aspects of an exemplary self-propelled irrigation system which may be used with example implementations of the present invention. As should be understood, the irrigation system disclosed in  FIGS.  1 - 4    are exemplary irrigation systems onto which the features of the present invention may be integrated. Accordingly, the figures are intended to be illustrative and any of a variety of systems (i.e. fixed systems as well as linear and center pivot self-propelled irrigation systems; corner systems) may be used with the present invention without limitation. 
     With reference now to  FIG.  1   , an exemplary irrigation machine  100  of the present invention is shown. As discussed herein, a key advantage of the present invention is the management of solar power to allow for off-the-grid irrigation of crops (e.g. using primarily selfproduced electrical power). The solar power to the system is preferably provided by one or more solar arrays  102  which may be composed of any number of solar panels. The solar array  102  of the present invention preferably may include any number of solar panels connected in series and/or parallel to provide the power requirements of the present invention. The power generated by the solar array  102  is output as a DC current which is directed from the solar array  102  to a charge controller  104 . 
     According to a preferred embodiment, the charge controller  104  of the present invention is preferably capable of maximum power point tracking (MPPT). Specifically, the charge controller  104  of the present invention is preferably programmed to measure the I-V curve output by the solar array and to adjust the load/duty ratio of the system using MPPT algorithms to maximize power extraction under all conditions. Accordingly, when an additional load is beneficial, the charge controller  104  may increase the applied load by causing the well pump  110  to begin or to increase the pumping of water from the well  118  to the water tank  114 . In this way, the charge controller  104  may both increase the rate of power extraction and store water under pressure for later use. 
     With further reference to  FIG.  1   , the charge controller  104  may additionally direct DC current to either one or more batteries  126 , or to an inverter  120 . The inverter  120  may convert the received DC current to AC current for instant use by the irrigation system as discussed further below. According to a preferred embodiment, the inverter  120  used with the present invention may be a single mode or multi-mode inverter. As shown in  FIG.  1   , the AC current may be provided to a variety of systems such water pumping systems and/or span driving systems  122 . An exemplary water pumping system may include a pump motor  108  which provides power to a downhole turbine pump  110  or the like. In operation, the pump  110  preferably is positioned under the water line of a well  118  or other water source. The pump  110  preferably provides water under pressure through a water storage pipe  112  for storage within an elevated water tower  114 . In addition to using the solar power to pump water into the water tower  114 , the system  100  preferably further uses the solar power to power the electro-mechanical systems of pivot point  106  and the irrigation span  120  as discussed further below. The water may also be simultaneously supplied to the irrigation system as commanded by the grower based on crop water demand, soil moisture status, planned irrigation schedule, etc. 
     During irrigation operations, the stored water within the elevated water tower  114  is preferably connected (directly or indirectly) via a water supply pipe/network  116  to a pivot point  106  and to one or more irrigation spans  120 . According to a preferred embodiment, the stored water within the elevated water tower  114  is preferably sufficient in volume and height to supply water at pressures which meet or exceed the pressure requirements of the sprinklers  126  of the irrigation span  120 . Preferably, the pivot controller  124  may receive feedback from one or more transducers  128  to monitor the water pressure provided by the water supply pipe/network  116 . Where the detected water pressure falls below the required levels for a given sprinkler set or VRI prescription, the pivot controller  124  preferably may create additional water pressure via an auxiliary pump, water source or the like. 
     As discussed above, the water tower  114  is preferably elevated to a height sufficient to create water pressure which meets or exceeds the rating of each sprinkler set usable with the irrigation span  120 . For example, where an irrigation span sprinkler set will require a minimum of 25 PSI, the water tower  114  is preferably sized and elevated to provide that level of pressure (plus a needed margin based on the type of system and expected losses). Generally, each foot of height provides 0.43 PSI (pounds per square inch) of pressure, so to achieve 25 PSI at the pivot (plus 5 PSI for other pressure losses), the water tower  114  would preferably be elevated to at least 70 feet or higher to provide the necessary pressure. 
     In the example of  FIG.  1   , a single solar array  102 , water tower  114  and pump  110  are shown. According to alternative embodiments, the present invention preferably may include any number of smaller pumps and storage tanks to gravity feed the irrigation system and to produce the pressure required for water distribution. Further, any number of different solar arrays may be combined within the present invention without limitation. 
     With reference now to  FIG.  2 A , a high level, overhead view of an exemplary irrigation field incorporating aspects of the present invention is provided. As shown, an exemplary field arrangement  200  may include a centrally located solar array  202  located near a water source  204   and one or more pivot points  206 - 212 . Ideally, the solar array  202  may be located very near the water source so that transmission loss from the solar array  202  is minimized. The water storage tank  226  may also be located near the water source and the solar array  202  minimizing the loss of water pressure through the water storage pipe  222  and the water supply pipe  224 . Thus, the water storage and transport system of the present invention may provide a long term, highly efficient, environmentally friendly and low maintenance, power storage system for providing water pressure to any number of irrigation spans  214 - 220 . The exemplary system  200  of the present invention may preferably further include a nitrogen generation/fertigation system  203  which may preferably be controlled and powered by the system of the present invention as discussed further herein. 
     Referring now to  FIG.  2 B , an enlarged overhead view of the exemplary nitrogen generation/fertigation system  203  shown in  FIG.  2 A  is provided. As shown, the exemplary nitrogen generation/fertigation system  203  of the present invention may preferably include a main nitrogen production unit  211 . The system  203  preferably further includes a feed stream device  207  which preferably provides a feed stream into the nitrogen production unit  211  via a feed conduit  209  or the like. The feed stream of the present invention may preferably include base feed-gas components such as molecular oxygen and molecular nitrogen. The feed stream may also work from ambient air by passing input air through an electric arc to create oxides of nitrogen which are then scrubbed from the flow with water to create nitric acid. 
     The feed stream provided by the feed stream device  207  is preferably transferred into the nitrogen product unit  211  where the nitrogen and other feed-gas components are preferably converted into a variety of nitrogen species. According to a preferred embodiment, the nitrogen production unit  211  preferably may be a plasma reactor or the like as known in the prior art. Accordingly, the nitrogen product unit  211  may receive the feed stream from the feed stream device  207 , where it is super-heated and converted to various oxidized nitrogen molecules in both solid and gaseous forms. These materials are then preferably pipe fed into the nitrogen storage/mixing chamber  215  for further processing, storage, and selective introduction into the irrigation system  200  for application. Withing the nitrogen storage/mixing chamber  215 , the oxidized nitrogen molecules may be condensed or otherwise reacted to produce molecules of nitrogen (e.g., nitrates, nitrites, nitrate salts and the like) using an absorber as known in the prior art. Any gas phase molecules produced by the absorber may preferably be recycled back to the nitrogen production unit  211  via a gas recycle conduit or the like  213 . The stored nitrogen molecules within the nitrogen storage/mixing chamber  215  may then preferably be held under pressure for selective introduction into the irrigation system  200 . 
     With reference now to  FIG.  3   , an exemplary electrical system  300  incorporating aspects of the present invention is shown. To complement and support the water distribution system discussed above, the electrical system  300  of the present invention preferably includes one or more solar panels  302 ,  304 ,  306  which convert solar radiation to DC current. The DC current from each solar panel  302 ,  304 ,  306  is preferably transmitted first to a combiner  308  and then to a charge controller  310 . The DC current may then be directly transmitted to a set of batteries  312  for storage. The charge controller  310  may also direct DC current to an inverter  314  which may preferably be a multi-mode inverter capable of converting AC to DC and DC to AC as needed. Additionally, the inverter  314  may receive and transmit AC current to and from an outside electric grid  324  which may be metered  322  to track net electrical consumption. The inverter  314  may further provide AC current to a main switchboard/irrigation controller  318  for selective transmission to various sub-systems including the irrigation system  320 , the well motor/pump  322  and other systems and common loads  321  such as lighting and the like. 
     According to a preferred embodiment, system charge controller  310  (together with other system controllers  318 ) may analyze and adjust charging periods to provide power for all subelements of the present invention. For example, the charge controllers  310  may selectively direct lower grade power (i.e., solar energy generated during shoulder periods and the like) to specific energy storage devices which provide power for applications not requiring higher grade power. For example, lower grade energy could be directed into a battery system or could selectively be provided to the nitrogen generation/fertigation system  319  for other uses such as nitrogen generation via an electric arc process and the like.. 
     With reference now to  FIG.  4   , an exemplary control device  400  which represents functionality to control one or more operational aspects of the irrigation systems  100 ,  300  of the present invention will now be discussed. As shown, the exemplary control device  400  preferably includes a processor  402 , a memory  406 , software modules  410  and a network interface  404 . The processor  402  provides processing functionality for the control device  400  and may include any number of processors, micro-controllers, or other processing systems. The processor  402  may execute one or more software modules/programs  410  that implement techniques described herein and may process stored sensor data  408  as discussed further below. The network interface  404  preferably provides functionality to enable the control device  400  to communicate with one or more networks  416  through a variety of components such as wireless access points, transceivers and so forth, and any associated software employed by these components (e.g., drivers, configuration software, and so on). 
     In implementations, the control device  400  preferably includes a position-determining module  414  which may receive input data from a global positioning system (GPS) receiver  418  or the like to calculate a location of the irrigation system  100 / 300 . Further, the control device  400  may be coupled to various drive tower controllers  422  to control and coordinate the movement of the irrigation system  100 . As shown, the control device  400  may further include a drive control module  412  to assist in controlling the movement of the system. Further, the control device  400  may preferably further include multiple inputs and outputs to receive data from sensors  420  and monitoring devices as discussed further below. The control device  400  may preferably additionally control and coordinate the operation of the nitrogen generation/fertigation system  424  and its subsystems as further discussed herein. 
     According to a first preferred embodiment, the control device  400  of the present invention may preferably implement power control algorithms to calculate the power needs for the irrigation of a given field. Based on these calculations, the algorithms of the present invention may selectively use precise amounts of stored, elevated water (i.e. pressurized) as needed to complete a given set of irrigation tasks while minimizing the need for supplemental power (i.e. from the grid). The control device  400  may preferably use the input data to calculate the total power available for the irrigation of a given field. According to a first preferred embodiment, the calculations may include a calculation of the total power available at a particular date and time. For example, this calculation may be as follows: 
     
       
         
           
             
               
                 TOTAL POWER AVAILABLE= 
               
             
             
               
                 NET SOLAR POWER GENERATION+BATTERY POWER STORED 
               
             
           
         
       
     
     Preferably, the algorithms of the present invention may further calculate the total power needed to complete the irrigation of a given field. An exemplary calculation may include input data such as: field slope, field area, traction, irrigation time, water pressure/pump requirements and the like. This may also be calculated based on prior usage of the irrigation machine. For example, the average of historical energy demand plus a safety factor (20%) could be used. Alternatively, the energy usage could be based on a ‘test run’ where the system is manually operated for a single pass through the field or based on a calculated value based on the expected current and voltage. Additional input data may include data such as: irrigation map data (i.e. GPS dimensions of a given field); soil type; soil moisture; weather data (including storm events, humidity, temperature, wind speed and direction); movement data (including speed and direction of the irrigation machine); and topographical data (including data regarding obstacles and the slope of the terrain to be irrigated). Where available, the calculations may include historic power usage data for the same field which may be adjusted for changes in conditions. Using sets of input data, the system of the present invention may preferably calculate the supplemental power required to irrigate a given field. An exemplary calculation may be as follows: 
     
       
         
           
             
               
                 SUPPLEMENTAL POWER REQUIRED= 
               
             
             
               
                 TOTAL POWER CONSUMPTION-TOTAL POWER AVAILABLE 
               
             
           
         
       
     
     According to a preferred embodiment, where supplemental power is required, the control device  400  may trigger the system to use water pressure supplied by the elevated water tower  114 . As discussed above, the elevated water tower  114  is preferably connected to a pivot point  106  and to one or more irrigation spans  120 . According to a preferred embodiment, the stored water within the elevated water tower  114  is preferably sufficient in volume and height to supply water at pressures which meet or exceed the pressure requirements of the sprinklers  126  of the irrigation span  120 . In this way, the control device  400  may use the stored water in the elevated water tower  114  to reduce the total power consumption of the irrigation system as needed. Accordingly, the system may reduce the amount of supplemental power used from the grid  324  or from generators. 
     Preferably, the pivot controller  124  may also receive feedback from one or more transducers  128  to monitor the water pressure provided by the water supply pipe/network  116 . According to a preferred embodiment, the pressure may be monitored using the pressure sensor at the pivot point or at the end of the machine and comparing it to the minimum acceptable pressure defined during design of the sprinkler package (e.g., irrigator design prior to installation). Further, the control device  400  of the present invention may preferably receive continual updates from all sensors and systems and may preferably dynamically calculate and update the supplemental power required for the irrigation system in real-time for a given field so that stored, pressurized water can be conserved when not needed. 
     According to an alternative preferred embodiment, the control device  400  of the present invention may alternatively use the stored, pressurized water to adjust for changes in anticipated solar power production. In this embodiment, the control device  400  of the present invention may preferably receive input data such as: MPPT system data, weather data, field mapping data, water storage level data, battery state-of-charge data, grid power and/or engine-genset power availability and cost, forecasted water demand data, current water and irrigation system energy demand data, and/or water pressure data. The control device  400  may preferably use the input data to control the power generation, power consumption, scheduling and electro-mechanical activities of the irrigation system. For example, the control device  400  may process selected input data (e.g., solar condition and MPPT load data) and determine/instruct changes to the rate of speed and/or other operating parameters of the irrigation system. For example, where the solar power output is low, the control device  400  may change the operating speed of the system to allow the system to complete an entire watering program without using grid power. Similarly, where solar power output is higher, the control device  400  may increase the speed of the system to maximize the power production during a high sunlight period. 
     According to further preferred embodiments, the control device  400  may be preferably further control other complimentary aspects of the irrigation machine to apply a defined depth of water to the field. For example, the control device  400  may be programmed to throttle down the sprinkler flow (using VRI valves at each sprinkler) to ensure excess water is not applied when machine speeds are reduced. At the same time, the control device  400  may preferably restrict the machine speed and related sprinkler flow changes based on soil moisture content, crops stress, weather, growth stage and the like. 
     According to further alternative embodiments, to allow for potentially higher machine ground speeds, the system may include an over-sized pump, irrigation machine and sprinkler package for a higher than optimum (for the crop/field) flowrate. In this embodiment, the system may preferably use the VRI valves to reduce the flow for normal operations. During operations requiring increased ground speeds, the controller may then preferably not cycle the VRI valves. This type of control may only work with sandy soils because the heavier clay soils have a fixed infiltration rate that limits the ability of the irrigation machine to apply water (instantaneous application rate) at higher rates. 
     The control device  400  may similarly use internal algorithms to time and schedule when to use solar power to pump water to an elevated water tower and/or to mechanically move system. For example, where a first day is predicted to generate a low amount of solar power, the system may execute an irrigation program requiring a lower speed. On a following day, the system may program and execute a VRI program requiring more power. In another example, where the weather data indicates that a high power generation day is to be followed by a low power generation day, the control device  400  may preferably adjust a given VRI program so that on the high power generating day, the system will directly use generated solar power to both operate the watering system and to supply all needed water pressure. In this way, the system may preserve the amount of water stored at elevation. On the next lower power generating day, the control device  400  may preferably adjust the VRI program to use water provided by the water tank for irrigation and to restrict the use of solar power to moving the irrigation span. The control device  400  may preferably also use stored battery energy along with estimate power generation to determine the ratio of water tank power vs solar power to use. Additionally, the system of the present invention may also charge and/or use battery energy based on the same input data. 
     The drive control module  412  of the present invention may receive continual updates from all sensors and systems of the present invention so that it may dynamically calculate and update VRI parameters in real-time as the irrigation system executes a given watering plan. For example, the drive control module  412  may receive and adjust target motor speeds based on solar power related data such as: MPPT data; levels of current and forecasted solar power generation; water storage levels; battery storage levels; grid power costs; time shifted grid power costs and the like. Additionally, the drive control module  412  may use the solar power related data in combination with other VRI prescription data to update VRI parameters of a given VRI prescription. Such VRI prescription data may include data such as: irrigation map data (i.e. GPS dimensions of a given field); soil/crop data (crop type, growth stage, irrigation history, soil type and/or measured soil moisture; weather data (including storm events, humidity, temperature, wind speed and direction); movement data (including speed and direction of the irrigation machine); and topographical data (including data regarding obstacles and the slope of the terrain to be irrigated). The drive control module  412  may also analyze the VRI data to trigger a higher rate of speed so that a total irrigation cycle is completed quickly enough to allow the system to initiate a second irrigation cycle to keep up with solar power production. 
     With reference now to  FIG.  5   , an alternative exemplary method  500  for managing power and loads during irrigation in accordance with the present invention shall now be discussed. As shown in  FIG.  5   , according to a first preferred embodiment, at a first step  502  the system may collect and update environmental data. At a next step  504 , the system may also receive and update forecast data. Preferably, this data may include factors impacting the amount of solar radiation available to the system and/or other VRI prescription data. These may include factors such as: solar radiation, cloud cover, precipitation, and the like. At a next step  506 , the system may then preferably calculate a photovoltaic (PV) production schedule which preferably stores the amounts of PV power which will be produced per segment of time for a given area of field. 
     At a next step  508 , the system may then preferably calculate one or more PV production /irrigation windows which identify and/or maximize the available PV power available for irrigation. Such production windows may define periods of time in which the generated PV meets or exceeds the power needed to execute a given irrigation plan. Alternatively, the production window may define periods of time in which the generated PV meets or exceeds the power needed to execute a given irrigation plan while also using various levels of supplemental power (e.g., battery stored, elevated water storage, limited grid-power). At a next step  510 , the system may preferably calculate and store parameters for a watering plan for a desired level of watering to be executed during the calculated PV production windows. At a next step  512 , the system may then preferably calculate and adjust the necessary drive speeds to execute the watering plan within the PV production windows. At a next step  513 , the system may preferably further calculate the need for stored energy outside of optimal PV production windows and may initiate the use of the stored energy to operate the machine and to provide pressurized water to the machine during sub-optimal solar generation periods. 
     According to a further preferred embodiment, the system of the present invention may preferably link to or extend a soil moisture probe into the ground and/or through a given root zone of a selected crop (step  514 ). According to a preferred embodiment, the probes for use with the present invention may include solar powered, GSM connected soil moisture probes or the like. In accordance with this preferred embodiment, the system may preferably apply a given test amount of targeted water (step  516 ) onto the soil probed by the soil moisture probe. At a next step  518 , the system may thereafter calculate one or more soil characteristics such as soil infiltration rates and the like. According to a further alternative preferred embodiment, other parameters may also be tested on the watered ground such as: evaporation rates, run-off levels and the available traction/slippage on the watered soil. These measured changes (or changes to other VRI prescription data) may then preferably be used by the system of the present invention to update, determine and/or refine changes in energy consumption by the system. These updates may then preferably be used in turn to update the calculated and/or prescribed drive speeds, PV windows, schedules and/or watering rates. 
     Referring now to  FIG.  6   , according to a further alternative embodiment, in lieu of steps  502 - 520 , the system at step  600  may calculate and/or receive irrigation schedules based on crop demand and soil moisture (along with weather forecasts, crop type, growth stage etc.). At a next step  602 , the system may calculate a forecasted water demand by day. At a next step  604 , the system may then compare the current and forecasted energy generation levels and energy and water storage levels. At a next step  605 , the system may then calculate an optimum time for irrigation that minimizes the use of backup energy (e.g., from the grid or engine genset). 
     While the above descriptions regarding the present invention contain much specificity, these should not be construed as limitations on the scope, but rather as examples. Many other variations are possible. For example, the communications provided with the present invention may be designed to be duplex or simplex in nature. Further, as needs require, the processes for transmitting data to and from the present invention may be designed to be push or pull in nature. Still, further, each feature of the present invention may be made to be remotely activated and accessed from distant monitoring stations. Accordingly, data may preferably be uploaded to and downloaded from the present invention as needed. 
     Accordingly, the scope of the present invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.