Patent Publication Number: US-2023163598-A1

Title: Microgrid system for solar water pumps

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of and priority to U.S. Provisional Application Ser. No. 63/283,036, filed Nov. 24, 2021, the entire contents of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     Field of the Disclosure 
     Embodiments of the present disclosure relate generally to methods and apparatus configured for use with water pumps and, in particular, to methods and apparatus that use single-phase microinverters in a three-phase configuration to provide microgrid output for solar water pumps. 
     Description of the Related Art 
     Conventional solar irrigation systems are well known. For example, such systems, typically, comprise one or more solar pumps that can be configured to pump water to one or remote locations, e.g., farmlands or other irrigatable areas. In some instances, the solar power needed to operate the one or more pumps is seasonal, e.g., only needed during irrigation seasons. Thus, during the off-season, the solar power is not needed and often wasted. Additionally, during irrigation seasons, as it is not necessary to irrigate at all possible times, solar power is not used. 
     Therefore, the inventors provide herein improved methods and apparatus that use single-phase microinverters in a three-phase configuration to provide microgrid output for solar water pumps. 
     SUMMARY 
     Methods and apparatus configured for use with water pumps are provided herein. In some embodiments, a microgrid system for water pumps comprises a solar array comprising three independent branches and a first pair of photovoltaic modules and a second pair of photovoltaic modules on each of the three independent branches, each of the first pair photovoltaic modules and the second pair of photovoltaic modules connected by a corresponding single-phase inverter connected in series with each other and connected to a common controller configured to connect the first pair photovoltaic modules and the second pair of photovoltaic modules to a grid during a first mode of operation and connect the first pair photovoltaic modules and the second pair of photovoltaic modules to a water pump during a second mode of operation, different from the first mode of operation. 
     In accordance with at least some embodiments, a method for supplying power to a water pump comprises a) determining if inverters are in an idle mode and no faults are present, b) if yes at a) sending PLC initialize command to the inverters, c) determining if the water pump is running in a correct phase sequence, and d) entering water pump run state and enabling a voltage/frequency (V/F) control of the water pump when yes at c). 
     These and other features and advantages of the present disclosure may be appreciated from a review of the following detailed description of the present disclosure, along with the accompanying figures in which like reference numerals refer to like parts throughout. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. 
         FIG.  1    is a block diagram of a system in accordance with embodiments of the present disclosure; 
         FIG.  2    is a block diagram of a three-phase solar water pump system in accordance with embodiments of the present disclosure; 
         FIG.  3    is a partial schematic diagram of the three-phase solar water pump system of  FIG.  2    in accordance with embodiments of the present disclosure; 
         FIG.  4    is a partial schematic diagram of the three-phase solar water pump system of  FIG.  2    in accordance with embodiments of the present disclosure; 
         FIG.  5    is a graph of nominal total dynamic head, flow rate, and corresponding efficiency in accordance with embodiments of the present disclosure; 
         FIG.  6    illustrates curves for summer (hot) and winter (cold) in accordance with embodiments of the present disclosure; 
         FIG.  7    is a flowchart of a method for supplying power to a solar water pump in accordance with embodiments of the present disclosure; 
         FIG.  8    is diagram of control box configured for use with the three-phase solar water pump system of  FIG.  2    in accordance with embodiments of the present disclosure; and 
         FIG.  9    is a state diagram of the startup sequence for a solar water pump in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure generally relate to methods and apparatus configured for use with solar water pumps. For example, methods and apparatus described herein use single-phase microinverters in a three-phase configuration to provide microgrid output for solar water pumps. In at least some embodiments, a system, for example, can comprise one or more solar panels, one or more microinverters, and control equipment, which can include a communications gateway or other suitable communication device. The system can be operable in two modes of operation, a first mode of operation (e.g., grid tied inverter mode, to produce power into a three-phase grid) and a second mode of operation (e.g., solar water pump mode (off-grid), to produce power for a three-phase submersible pump or any other type of pump). 
       FIG.  1    is a block diagram of a system  100  (e.g., power conversion system) in accordance with one or more embodiments of the present disclosure. The diagram of  FIG.  1    only portrays one variation of the myriad of possible system configurations. The present disclosure can function in a variety of environments and systems. 
     The system  100  comprises a structure  102  (e.g., a user&#39;s structure), such as a residential home or commercial building, having an associated DER  118  (distributed energy resource). The DER  118  is situated external to the structure  102 . For example, the DER  118  may be located on the roof of the structure  102  or can be part of a solar farm. The structure  102  comprises one or more loads and/or energy storage devices  114  (e.g., appliances, electric hot water heaters, thermostats/detectors, boilers, water pumps, and the like), which can be located within or outside the structure  102 , and a DER controller  116 , each coupled to a load center  112 . Although the energy storage devices  114 , the DER controller  116 , and the load center  112  are depicted as being located within the structure  102 , one or more of these may be located external to the structure  102 . 
     The load center  112  is coupled to the DER  118  by an AC bus  104  and is further coupled, via a meter  152  and a MID  150  (microgrid interconnect device), to a grid  124  (e.g., a commercial/utility power grid). The structure  102 , the energy storage devices  114 , DER controller  116 , DER  118 , load center  112 , generation meter  154 , meter  152 , and MID  150  are part of a microgrid  180 . It should be noted that one or more additional devices not shown in  FIG.  1    may be part of the microgrid  180 . For example, a power meter or similar device may be coupled to the load center  112 . 
     The DER  118  comprises at least one renewable energy source (RES) coupled to power conditioners  122 . For example, the DER  118  may comprise a plurality of RESs  120  coupled to a plurality of power conditioners  122  in a one-to-one correspondence (or two-to-one). In embodiments described herein, each RES of the plurality of RESs  120  is a photovoltaic module (PV module), although in other embodiments the plurality of RESs  120  may be any type of system for generating DC power from a renewable form of energy, such as wind, hydro, and the like. The DER  118  may further comprise one or more batteries (or other types of energy storage/delivery devices) coupled to the power conditioners  122  in a one-to-one correspondence, where each pair of power conditioner  122  and a battery  141  may be referred to as an AC battery  130 . 
     The power conditioners  122  invert the generated DC power from the plurality of RESs  120  and/or the battery  141  to AC power that is grid-compliant and couple the generated AC power to the grid  124  via the load center  112 . The generated AC power may be additionally or alternatively coupled via the load center  112  to the one or more loads (e.g., a solar pump) and/or the energy storage devices  114 . In addition, the power conditioners  122  that are coupled to the batteries  141  convert AC power from the AC bus  104  to DC power for charging the batteries  141 . A generation meter  154  is coupled at the output of the power conditioners  122  that are coupled to the plurality of RESs  120  in order to measure generated power. 
     In some alternative embodiments, the power conditioners  122  may be AC-AC converters that receive AC input and convert one type of AC power to another type of AC power. In other alternative embodiments, the power conditioners  122  may be DC-DC converters that convert one type of DC power to another type of DC power. In some of embodiments, the DC-DC converters may be coupled to a main DC-AC inverter for inverting the generated DC output to an AC output. 
     The power conditioners  122  may communicate with one another and with the DER controller  116  using power line communication (PLC), although additionally and/or alternatively other types of wired and/or wireless communication may be used. The DER controller  116  may provide operative control of the DER  118  and/or receive data or information from the DER  118 . For example, the DER controller  116  may be a gateway that receives data (e.g., alarms, messages, operating data, performance data, and the like) from the power conditioners  122  and communicates the data and/or other information via the communications network  126  to a cloud-based computing platform  128 , which can be configured to execute one or more application software, e.g., a grid connectivity control application, to a remote device or system such as a master controller (not shown), and the like. The DER controller  116  may also send control signals to the power conditioners  122 , such as control signals generated by the DER controller  116  or received from a remote device or the cloud-based computing platform  128 . The DER controller  116  may be communicably coupled to the communications network  126  via wired and/or wireless techniques. For example, the DER controller  116  may be wirelessly coupled to the communications network  126  via a commercially available router. In one or more embodiments, the DER controller  116  comprises an application-specific integrated circuit (ASIC) or microprocessor along with suitable software (e.g., a grid connectivity control application) for performing one or more of the functions described herein. For example, the DER controller  116  can include a memory (e.g., a non-transitory computer readable storage medium) having stored thereon instructions that when executed by a processor perform a method for grid connectivity control, as described in greater detail below. 
     The generation meter  154  (which may also be referred to as a production meter) may be any suitable energy meter that measures the energy generated by the DER  118  (e.g., by the power conditioners  122  coupled to the plurality of RESs  120 ). The generation meter  154  measures real power flow (kWh) and, in some embodiments, reactive power flow (kVAR). The generation meter  154  may communicate the measured values to the DER controller  116 , for example using PLC, other types of wired communications, or wireless communication. Additionally, battery charge/discharge values are received through other networking protocols from the AC battery  130  itself. 
     The meter  152  may be any suitable energy meter that measures the energy consumed by the microgrid  180 , such as a net-metering meter, a bi-directional meter that measures energy imported from the grid  124  and well as energy exported to the grid  124 , a dual meter comprising two separate meters for measuring energy ingress and egress, and the like. In some embodiments, the meter  152  comprises the MID  150  or a portion thereof. The meter  152  measures one or more of real power flow (kWh), reactive power flow (kVAR), grid frequency, and grid voltage. 
     The MID  150 , which may also be referred to as an island interconnect device (IID), connects/disconnects the microgrid  180  to/from the grid  124 . The MID  150  comprises a disconnect component (e.g., a contactor or the like) for physically connecting/disconnecting the microgrid  180  to/from the grid  124 . For example, the DER controller  116  receives information regarding the present state of the system from the power conditioners  122 , and also receives the energy consumption values of the microgrid  180  from the meter  152  (for example via one or more of PLC, other types of wired communication, and wireless communication), and based on the received information (inputs), the DER controller  116  determines when to go on-grid or off-grid and instructs the MID  150  accordingly. In some alternative embodiments, the MID  150  comprises an ASIC or CPU, along with suitable software (e.g., an islanding module) for determining when to disconnect from/connect to the grid  124 . For example, the MID  150  may monitor the grid  124  and detect a grid fluctuation, disturbance or outage and, as a result, disconnect the microgrid  180  from the grid  124 . Once disconnected from the grid  124 , the microgrid  180  can continue to generate power as an intentional island without imposing safety risks, for example on any line workers that may be working on the grid  124 .In some alternative embodiments, the MID  150  or a portion of the MID  150  is part of the DER controller  116 . For example, the DER controller  116  may comprise a CPU and an islanding module for monitoring the grid  124 , detecting grid failures and disturbances, determining when to disconnect from/connect to the grid  124 , and driving a disconnect component accordingly, where the disconnect component may be part of the DER controller  116  or, alternatively, separate from the DER controller  116 . In some embodiments, the MID  150  may communicate with the DER controller  116  (e.g., using wired techniques such as power line communications, or using wireless communication) for coordinating connection/disconnection to the grid  124 . 
     A user  140  can use one or more computing devices, such as a mobile device  142  (e.g., a smart phone, tablet, or the like) communicably coupled by wireless means to the communications network  126 . The mobile device  142  has a CPU, support circuits, and memory, and has one or more applications, such as an application  146  (e.g., a grid connectivity control application) installed thereon for controlling the connectivity with the grid  124  as described herein. The application  146  may run on commercially available operating systems, such as IOS, ANDROID, and the like. 
     In order to control connectivity with the grid  124 , the user  140  interacts with an icon displayed on the mobile device  142 , for example a grid on-off toggle control or slide, which is referred to herein as a toggle button. The toggle button may be presented on one or more status screens pertaining to the microgrid  180 , such as a live status screen (not shown), for various validations, checks and alerts. The first time the user  140  interacts with the toggle button, the user  140  is taken to a consent page, such as a grid connectivity consent page, under setting and will be allowed to interact with toggle button only after he/she gives consent. 
     Once consent is received, the scenarios below, listed in order of priority, will be handled differently. Based on the desired action as entered by the user  140 , the corresponding instructions are communicated to the DER controller  116  via the communications network  126  using any suitable protocol, such as HTTP(S), MQTT(S), WebSockets, and the like. The DER controller  116 , which may store the received instructions as needed, instructs the MID  150  to connect to or disconnect from the grid  124  as appropriate. 
       FIG.  2    is a block diagram of a system  200  (a three-phase water pump system) in accordance with embodiments of the present disclosure. The system  200  comprises a solar array  208  (e.g., the DER  118  comprising the RESs  120 ), a controller  203  (e.g., DER controller  116 ), a water pump  202  (e.g., a submersible water pump or other device suitable for use with the embodiments described herein), a grid (e.g., the grid  124 ), and an optional cloud-based computing platform (e.g., cloud-based computing platform  128 ). 
     Table 1 lists grid tied operating parameters of the system  200 . 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
             
            
               
                   
                 AC OUTPUT 
                 3-Ø, 4 Wire 
               
               
                   
                 TDH 
                 &lt;3% @ Nominal Power 
               
               
                   
                 DC/AC Ratio 
                 up to 1.5 
               
               
                   
                   
               
            
           
         
       
     
     The system  200  is operable in two modes of operation. For example, as noted above, the system  200  can be operable in a first mode of operation (e.g., grid tied inverter mode, to produce power into a three-phase grid) and a second mode of operation (e.g., solar water pump mode (off-grid), to produce power for a three-phase submersible pump). In the second mode of operation, the system  200  is capable of producing power sufficient to meet various daily water output requirements demands (e.g., depending on season, as summer or winter). To operate in the two modes of operation, the solar array  208  can comprise six or more RESs  120 . For example, the solar array  208  can comprise a plurality of two or more RESs connected by a conditioner (single power). In at least some embodiments, the solar array  208  can comprise three branches  201   a - 201   c  each comprising two pairs of RESs  205 ,  207  (e.g., a first pair of photovoltaics and a second pair of photovoltaics) connected by a power conditioner (single-phase). Thus, in the first mode of operation, all pairs of the RESs (e.g., RESs  205  and the RESs  207 ) in the three branches  201   a - 201   c  are configured to output to the grid, and in the second mode of operation all pairs of the RESs (e.g., RESs  205  and the RESs  207 ) in the three branches  201   a - 201   c  are configured to output to the water pump  202 . 
       FIG.  3    is a partial schematic diagram of the system  200  in accordance with embodiments of the present disclosure. For example, each pair of RESs  205 ,  207  in the three branches  201   a - 201   c  are connected in series with each other, and the three branches  201   a - 201   c  connect to the controller  203 . For example, a first power conditioner  300  can be connected to the pair of RESs  205  in the first branch  201   a , a second power conditioner  302  can be connected to the pair of RESs  205  in the second branch  201   b , a third power conditioner  304  can be connected to the pair of RESs  205  in the third branch  201   c . For example, L and N outputs (load and neutral outputs) from the power conditioners  300 - 304  connect to corresponding inputs of an LCF filter  306 , which includes one or more inductors, Q-relays, capacitors, or other suitable electronic device, and has outputs that connect to the grid  124  and the controller  203  (e.g., a gateway), as illustrated in  FIG.  3   . The LCF filter  306  can be a component of the controller  203  or a separate component therefrom. Similarly, PLC 1  and PLC 2  outputs (first power line communication and second power line communication outputs) from the power conditioners  300 - 304  connect to inputs of controller  203 , as illustrated in  FIG.  3   . The wiring configuration of  FIG.  3   , which illustrates power conditioners  300 - 304  wired in Wye or Star configuration, allows the power conditioners  300 - 304  (single-phase) to operate in a three-phase configuration. Other wiring configurations can also be used to allow the power conditioners  300 - 304  (single-phase) to operate in a three-phase configuration. For example, as described in greater detail below,  FIG.  4    shows power conditioners  400 - 404  wired in delta configuration which can also connect to a Grid. 
     A harness  308  (three-phase harness) can be used to house the cables (wires) used to connect the power conditioners  300 - 304 , the LCF filter  306 , the grid  124 , and the controller  203  to each other. 
       FIG.  4    is a partial schematic diagram of the system  200  in accordance with embodiments of the present disclosure. For example, a first power conditioner  400  can be connected to the pair of RESs  207  in the first branch  201   a , a second power conditioner  402  can be connected to the pair of RESs  207  in the second branch  201   b , a third power conditioner  404  can be connected to the pair of RESs  207  in the third branch  201   c . For example, L and N outputs (load and neutral outputs) from the power conditioners  400 - 404  connect to corresponding inputs of an LCF filter  406 , which includes one or more inductors, Q-relays, capacitors, or other suitable electronic device, and has outputs that connect to the water pump  202  and the controller  203  (e.g., a gateway), as illustrated in  FIG.  4   . Similarly, PLC 1  and PLC 2  outputs (first power line communication and second power line communication outputs) from the power conditioners  400 - 404  connect to inputs of controller  203 , as illustrated in  FIG.  4   . As with the wiring configuration of  FIG.  3   , the wiring configuration of  FIG.  4    allows the power conditioners  400 - 404  (single-phase) to operate in a three-phase configuration. 
     The harness  308  can be used to house the cables (wires) used to connect the power conditioners  400 - 404 , the LCF filter  406 , the water pump  202 , and the controller  203  to each other. 
     The water pump  202  can be any suitable poly-phase motor water pump (e.g., a 3 phase water pump). For example, a factor for determining a type of pump that can be used in accordance with the present disclosure can include a minimum amount of water that has to be pumped out every day, a motor-pump rating, and a total dynamic head. For example, in at least some embodiments, the water pump  202  can be a submersible pump having a 5 hp rating, a voltage of about 300 Vrms, a speed of about 2800 rpm to about 3000 rpm (e.g., about 2450 rpm), an efficiency of about 78%, and a power factor of about 0.78. Additionally, the water pump  202  can have a rated power of about 4 kW (hp) to about 5.5 kW (hp), a nominal total dynamic head of about 50 m, a nominal flow rate of about 280 lit/min, and a nominal efficiency of about 60%. In at least some embodiments, the water pump  202  can comprise a variable speed or single speed motor. 
     In at least some embodiments, to start the water pump  202  (e.g., a 5 hp water pump), a high start current may be required. Accordingly, the solar array  208  can comprise six RESs to ten RESs to start the pump. For example, in at least some embodiments, the solar array  208  can comprise six RESs, as illustrated in  FIG.  2   , e.g., a pair of RESs  207  in each of the three branches  201   a - 201   c . Alternatively, in at least some embodiments, the solar array  208  can comprise  10  RESs, e.g., an extra pair of RESs  207  in a fourth branch (not shown). As the system  200  is a three phase system, typically, each phase comprises the same number of power conditioners  122 . Thus, in at least some embodiments, the power conditioners can be implemented in sets of threes (3&#39;s). While the present disclosure shows  6  power conditioners (two (2) power conditioners per branch— 201   a ,  201   b ,  201   c ), adding one more power conditioner per branch equates to nine (9) power conditioners, adding two power conditioners puts us at 12 and so on. To overcome the high starting current, however, in at least some embodiments one or more unbalance branches can be used, e.g., having a total number of power conditioners that is not a multiple of 3. Additionally, in at least some embodiments, the solar array  208  (e.g., six RESs to ten RESs) can produce 48,000 Wp (Watt-peak), which depending on a shut-off dynamic head (e.g., 50 m, 70 m, 100 m, etc.), can produce 100,800 liters/day (e.g., from a total head of 50 m), 67,200 liters/day (e.g., from a total head of 70 m), and 43,200 liters/day (e.g., from a total head of 100 m), respectively. 
     Table 2 lists the second mode of operation, e.g., water pump mode (off-grid) operating parameters. 
     
       
         
           
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
             
            
               
                 Water Pump Power Rating 
                 5 
                 HP 
               
            
           
           
               
               
            
               
                 Inverter Efficiency 
                 93% @ 80% of Rated power 
               
               
                 Output 
                 3-Ø, 3 Wire, R-Y-B, about 50 Hz 
               
               
                 Rated Motor Frequency (HZ) 
                 48-52 
               
            
           
           
               
               
               
            
               
                 Frequency Operation 
                 0-52 Hz 
                 (e.g., about 20 Hz ) 
               
               
                 Voltage Operation 
                 0-240 V 
                 (e.g., about 90 V) 
               
               
                 Rated Motor Voltage 
                 230 
                 V 
               
            
           
           
               
               
            
               
                 Motor Operation 
                 Constant V/F 
               
               
                 Output Characteristics 
                 Filtered AC output voltage 
               
               
                 Balance Supply 
                 Phase Balancing: 
               
               
                 Water Output 
                 21 liters of water per watt peak of PV 
               
               
                   
                 array, from a Total Dynamic Head of 50 
               
               
                   
                 meter and the shut off head being at 
               
               
                   
                 least 70 meter 
               
               
                   
               
            
           
         
       
     
     Some of the operating parameters of the controller  203  are listed in Table 2 to Table 5 below. For example, Table 3 lists monitoring and control operating parameters of the controller  203 . 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
             
            
               
                   
                 Parameters 
                 Electrical Parameters (V, P), 
               
               
                   
                   
                 Generation, Liters/Day 
               
               
                   
                 Alarm 
                 Fault - Dry Run, Short Circuit 
               
               
                   
                 Communication 
                 GPRS/Bluetooth/Ethernet/WiFi 
               
               
                   
                 Customer Interface 
                 Mobile App Based 
               
               
                   
                 Government Interface 
                 Web Based 
               
               
                   
                 Service 
                 Ticket Management through App 
               
               
                   
                 Control 
                 Over The Air Firmware Upgrade 
               
               
                   
                 Additional Port 
                 A Port for adding Irradiance 
               
               
                   
                 (Desired) 
                 Sensor Data (Not Essential) 
               
               
                   
                   
               
            
           
         
       
     
     Table 4 lists data and security operating parameters of the controller  203 . 
     
       
         
           
               
               
             
               
                 TABLE 4 
               
               
                   
               
             
            
               
                 Storage 
                 Local - 1 Year, Cloud - 5 years 
               
               
                 Communication 
                 Encrypted Communication TLS/SSL/X.509 
               
               
                 Authentication 
                 Password Protection 
               
               
                 Format of MSG (Preferred) 
                 JSON 
               
               
                   
               
            
           
         
       
     
     Table 5 lists LCD operating parameters of the controller  203 . 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
             
            
               
                   
                 Items to display 
                 Mode; Generation (Averaged); Electrical 
               
               
                   
                   
                 Parameters; and Fault feedback. 
               
               
                   
                   
               
            
           
         
       
     
       FIG.  5    is a graph of nominal total dynamic head, flow rate, and corresponding efficiency in accordance with embodiments of the present disclosure. For example, the data of  FIG.  5    illustrates a water pump performance curve that is supplied by a water pump vendor, which can be used to estimate if the system  200  will be able to generate the water pumping requirement. 
       FIG.  6    illustrates curves for summer (hot) and winter (cold) in accordance with embodiments of the present disclosure. For example, the irradiation profiles of  FIG.  6    (in conjunction with the performance curve in  FIG.  5   ) are used to estimate the water production for the profile. 
       FIG.  7    is a flowchart of a method  700  for supplying power to a solar water pump,  FIG.  8    is diagram of a control box  800  configured for use with the system  200  of  FIG.  2   , and  FIG.  9    is a state diagram  900  of a startup sequence for a solar water pump in accordance with embodiments of the present disclosure. 
     For example, in at least some embodiments, a system (e.g., the system  200 ) comprises a switch  802  (manual switch) at the control box  800  (e.g., the controller  203 ), which comprises a plurality of sensors, relays, modems, controllers (e.g., similar to the DER controller  116 ), drivers, LEDs, circuit breakers, cabling, displays, etc. The manual switch will have three positions 1) OFF, 2) WATER PUMP MODE, and 3) GRID MODE. In the OFF position, the system  200  is idle (e.g., output power is de-energized). When a user turns the switch  802  to the WATER PUMP MODE, the control box  800  (via controller  804 ) actuates one or more relays  810  (included in hardware  808 ) inside the control box  800  to direct power to a water pump electrical output. For example, at  702 , the method  700  comprises determining if power conditioners are in an idle mode and no faults are present (see  FIGS.  9   , at  902  and  904 ). If the power conditioners are in an idle mode and no faults are present, at  704 , the method  700  comprises sending PLC initialize command (see  FIG.  9   , at  906 ) to the power conditioners. If a fault is present, a flag can be triggered and all power conditioners are placed in idle mode (see  FIG.  9   , at  907 ). 
     Next, in at least some embodiments, the method  700  can comprise determining if the DM (data module, which is a set of parameters used by the controller firmware) initialize values have been received at the power conditioners (see  FIG.  9   , at  908 ). If no at  908 , the control box  800  can try “N” more times (e.g., a predetermined amount) before a fault is triggered (see  FIG.  9   , at  909 ). If yes at  908 , next, the method  700  can comprise a start dry run detect, an open circuit detect, and/or a start phase sequence (see  FIG.  9   , at  910 ). For example, the control box  800  communicates with power conditioners (e.g., the power conditioner  122 ) via PLC to start water pump operation (e.g., the water pump  202 ). The power conditioners will begin a start-up routine to form a 3 phase grid at a low frequency and voltage (see  FIG.  9   , at  912 ). 
     Next, at  706 , the method  700  comprises determining if the pumps are running in a correct phase sequence (see  FIG.  9   , at  914 ). For example, the control box  800  (via internal voltage and current sensors  806 ) determine if the 3 phase voltage phase sequence is correct and, if so, operation will continue. For example, in at least some embodiments, a correct phase sequence can correspond to the motor driving the water pump spinning in a correct direction. If no at  914 , the system  200  will restart until the correct phase sequence is achieved (see  FIG.  9   , at  914 ). 
     Next, at  708 , the method  700  comprises entering solar water pump (SWP) run state and enabling V/F control (see  FIG.  9   , at  916 ). For example, once the correct phase sequence is confirmed, the control box  800  periodically (e.g., a predetermined amount of times of about every 10 seconds) communicates with the power conditioners to implement/enable a voltage/frequency (V/F) control, e.g., a common induction motor control technique. For example, in the case of a water pump, in at least some embodiments, the power consumed (e.g., a maximum) by the water pump can be proportional to a cubed of the water pump shaft speed, which will be mostly proportional to the excitation electrical frequency. Therefore, the use of available PV power can be maximized by adjusting the excitation frequency generated by the power conditioners. 
     Next, when a user changes the switch  802  to GRID MODE, the system  200  will shut down and go to the idle state (see  FIGS.  9   , at  918  and  920 , respectively), then the control box  800  will actuate internal relays to direct power to a grid port (e.g., not the SWP port). The control box  800  then communicates via PLC with the power conditioners to command the power conditioner to start producing power onto the Grid. 
     One or more additional features can be provided in a PCU control  812 . For example, in at least some embodiments, the PCU control  812  can comprise hard shut down, soft shut down, extended V/F operation, synchronization, phase adjustment, V/F ratio and limits, etc. 
     While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.