Patent Publication Number: US-2023155410-A1

Title: Wireless power transfer for a photovoltaic power source

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. Pat. Application No. 17/542,707, filed on Dec. 6, 2021, which claims priority from U.S. Provisional Pat. Application No. 63/123,659, entitled “INNOVATIVE SYSTEM COMBINES PHOTOVALTAIC POWER SOURCE,” filed on Dec. 10, 2020, which are hereby incorporated by reference as if set forth in full in this application for all purposes. 
    
    
     BACKGROUND 
     The disclosure relates generally to wireless photovoltaic (PV) power systems, and more specifically, to wireless power transfer for a PV power source. 
     Generally, PV power sources are electronic devices that produce electric current at a junction of two substances exposed to light (i.e., convert light into electricity). PV power sources can be unstable due to inconsistencies of light, which has contributed to a lack of wireless power designs that use PV power sources. 
     Thus, there is a need for a wireless PV power systems. 
     SUMMARY 
     According to one or more embodiments, a wireless photovoltaic power system is provided. The wireless photovoltaic power system includes one or more photovoltaic cell units that provide power. Each of the one or more photovoltaic cell units include a photovoltaic cell. The wireless photovoltaic power system includes a first wireless power device that receives the power. The first wireless power device includes a coil that provides a magnetic field to wirelessly transfer the power to a second wireless power device. The first wireless power device provides a combinational implementation of a maximum power point tracking of the one or more photovoltaic cell units and a power control of a load. 
     According to one or more embodiments, the above wireless photovoltaic power system can be implemented as a method, an apparatus, and/or a computer program product. 
     Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein. For a better understanding of the disclosure with the advantages and the features, refer to the description and to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The forgoing and other features, and advantages of the embodiments herein are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG.  1    depicts a diagram of a system in accordance with one or more embodiments; 
         FIG.  2    depicts a diagram in accordance with one or more embodiments; 
         FIG.  3    depicts a method in accordance with one or more embodiments; 
         FIG.  4    depicts a method in accordance with one or more embodiments; 
         FIG.  5    depicts a method in accordance with one or more embodiments; and 
         FIG.  6    depicts a system in accordance with one or more embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments disclosed herein may include apparatuses, systems, methods, and/or computer program products (e.g., a wireless PV power system) that wirelessly transfers power of a PV power source. By way of example, one or more embodiments of the wireless PV power system can combine one or more PV power sources or PV cells with wireless power charging to energize a battery. 
     One or more technical effects, advantages, and benefits of the wireless PV power system include enabling maximum power point tracking (MPPT) of the one or more PV cells and/or implementing optimal constant current constant voltage (CCCV) charging for one or more batteries using minimal hardware. The wireless PV power system can also transfer energy stored in the one or more batteries to a consuming device, which may also be wirelessly coupled or uncoupled from the one or more PV cell. Further, one or more embodiments of the wireless PV power system include connecting multiple PV cells to a single wireless power transmitter, while an optimal MPPT is individually performed for each of the multiple PV cell, with minimal hardware overhead. 
       FIG.  1    shows a diagram  100  of a system (e.g., a wireless PV power system) in accordance with one or more embodiments. The system comprises wireless power devices  101  and  102  (e.g., a wireless power unit and/or a transmitter-receiver device). Both of these devices  101  and  102  can act as a transmitter and/or a receiver based on a particular operation of the wireless PV power system. For ease of explanation, and without particularly limiting the dual functions of the wireless power devices  101  and  102 , these devices  101  and  102  are referred herein as Tx  101  and Rx  102 , respectively. 
     According to one or more embodiments, the Tx  101  can be any device that can generate electromagnetic energy from one or more PV cells  105  (e.g., AC power source) to a space around the Tx  101  that is used to provide power to the Rx  102  and/or one or more devices  106 . The Rx  102  is any device that can receive, use, and/or store the electromagnetic energy when present in the space around the Tx  101 . Note that the Rx  102  can have a similar or the same component structure as the Tx  101 , and vice versa. Further, according to one or more embodiments, the Rx  102  can operate as a Tx and provide electromagnetic energy from one or more battery packs  107  to the Tx  101  operating as a Rx and, in turn, the one or more devices  106 . 
     As shown in  FIG.  1   , the Tx  101  includes circuitry for generating and transmitting the electromagnetic energy (i.e., transmitting power). The circuitry of the Tx  101  may include a transmitter coil  110 ; a resonant capacitor  115 ; a shunt resistor  116  for AC current measurement; a driver/rectifier  120  (e.g., half bridge, full bridge, diode bridge rectifier, etc.); a controller  125 , which further includes an input/output (I/O) module  126  and firmware  127 ; a rectifier capacitor  130 . 
     According to one or more embodiment, the Tx  101  includes an inductor implemented as coil  110  that is driven by a field-effect transistor (FET) (e.g., the driver/rectifier  120 ) controlled by the controller  125 . The coil  110  of the Tx  101  (and a coil of the Rx  102 ) can include standard electrical wiring copper wires folded and/or Litz wires. 
     For example, the coil  110  and the resonant capacitor  115  provide an LC circuit for generating an inductive current in accordance with operations of the driver/rectifier  120  and the controller  125  to support power transmissions. Further, according to one or more embodiments, the driver/rectifier  120  can be based on commercially available half-wave rectification; full-wave rectification; FET based full-wave rectification; and any combination thereof, or the like. For example, the driver/rectifier  120  can be any rectifier using one or more components, such as 4 diodes (e.g., asynchronous rectifier), 2 didoes and 2 FETs (half synchronous), 4 FET (synchronous), or 2 capacitors and 2 switches, that are controlled by either a dedicated logic circuit or the controller  125 . For instance, the driver/rectifier  120  can be a four diode bridge or use a single diode to produce half wave rectifier. The driver/rectifier  120  is followed by the rectifier capacitor  130 . 
     Another side of the resonant capacitor  115  can be connected to a ground GND (i.e., for the single and dual FET topology) and to the second half of the full bridge (i.e., for the 4 FET topology). The coil  110  in the Tx  101  can be used to inductively couple to the coil of the Rx  102  and is connected to the resonant capacitor  115  (e.g., a serial resonance capacitor). 
     According to one or more embodiments, the controller  125  can include a sensing circuit, circuitry, and/or software, for sensing voltage and/or current of the Tx  101 . The controller  125  can control and/or communicate any part of the Tx  101  to provide modulation injections as needed for power transfer. The controller  125  can include software therein (e.g., the firmware  127 ) that logically provides one or more of a FIR equalizer, an analyzer of in-band communication data, a selector for selecting a ping, a coupler for dynamically determining a coupling factor, a regulator for dynamically determining an operating frequency, etc. In this regard, the controller  125  can utilize a system memory and a processor, as described herein, to store and execute the firmware  127 . According to one or more embodiments, the controller  125  can be utilized to perform computations required by the Tx  101  or any of the circuitry therein. 
     According to one or more embodiments, the controller  125  can utilize the I/O module  126  as an interface to transmit and/or receive information and instructions between the controller  125  and elements of the Tx  101  (e.g., such as the driver/rectifier  120  and/or any wiring junction or shunt resistor  116 ). For instance, the controller  125  can include a sensing circuit, circuitry, unit, and/or software for sensing voltage and/or current of the Tx  101  (e.g., sensing voltage and/or current from the one or more PV cells  105  or shunt resistor  116 ). According to one or more embodiments, the controller  125  can sense, through the I/O module  126  one or more currents or voltages, such as a AC input voltage (Vin) and a AC resonance circuit voltage (Vac). According to one or more embodiments, the controller  125  can activate, through the I/O module  126 , one or more switches to change the resonance frequency (as the Rx  102  and/or the Tx  101  can include multiple switches for multiple frequencies). According to one or more embodiments, the controller  125  can may utilize the firmware  127  as a mechanism to operate and control operations of the Tx  101 . In this regard, the controller  125  can be a computerized component or a plurality of computerized components adapted to perform methods such as described herein (e.g., MPPT operations/algorithms, CCCV charging operations/algorithms, burst mode operations, as well as others modes of operation). According to one or more embodiment, the Tx  101  provides a combinational implementation of MPPT of the one or more PV cells  105  and a power control of the one or more devices  106  (e.g., a power consuming device or a load). Further, the controller  125  can determine in which transmitter and/or receiver modes to operate the Tx  101 . MMPT operations include when an electronic DC to DC converter optimizes a match between a solar array (i.e., the PV cells  105 ) and the battery pack  107 . The CCCV charging operations/algorithms include implementing a dynamic model battery charge based on a constant current stage and a constant voltage stage. 
     The Rx  102  includes circuitry for receiving, providing, and/or storing the electromagnetic energy, which can be further provided to a load therein. The load can be a single instance or any combination of electronic components, such as the one or more one or more battery packs  107 , as well as other circuit components (e.g., resistors, capacitors, etc.). By way of example, the Rx  102  can be configured to provide CCCV operations to control a charging of the battery pack  107 . 
     According to one or more embodiments, the Rx  102  includes at least the coil (as describe herein), which is configured to interact with a magnetic field of the Tx  101  to wirelessly obtain induced power that charges the one or more battery packs  107 . The Rx  102 , itself, can further include one or more capacitors for storing the induced power. The Rx  102  can include a controller as described herein and/or feedback circuitry to communicate with the Tx  101 . 
     According to one or more embodiments, for a standalone PV cell (i.e., when there is no power consuming device coupled to the one or more PV cells  105 ), the Tx  101  can operate as a transmitter only. 
     According to one or more embodiments, the wireless PV power system can include one or more PV cell units  140 , each of which can have a similar structure. For instance, the PV cell unit  140  can include at least a capacitor  141 , a switch  142  (e.g., a switching FET), and a ground GND. The capacitor  141  can smooth out power generated by the PV cell  105  (e.g., take power from different time periods for the corresponding PV cell  140 ) to control/optimize output of the PV cell unit  140 . An output of each PV Cell units  140  can be connected to the one or more devices  106  and/or the coil  110 . For example, multiple PV cell units  140  can be connected in parallel. In turn, the wireless PV power system utilizes an optimize MPPT operation for the combined PV cell units  140  (i.e., the controller  125  finds a best single operation voltage that would provide a highest combined power from the PV cell units  140  when the PV cells  105  therein all operate at same voltage). 
     As another example, each PV cell  105  in the multiple PV cell units  140  can be controlled separately by activating the corresponding switch  142  and connecting the corresponding capacitor  141  and/or the corresponding PV cell  105 . A capacitance of the capacitor  141  is configured to be significantly higher than a capacitance of a stabilization capacitor (e.g., stabilization capacitor  230  of  FIG.  2    described herein). The controller  125  can also provide individual MPPT control for each of the PV cells  105  and operate each of the PV cells  105  at an optimal voltage for maximal power. 
     As indicated herein, the controller  125  can determine in which mode to operate the Tx  101 , either as transmitter and/or as receiver (as both options are possible in terms of hardware of the Tx  101  and the firmware  127 . According to one or more embodiments, the one or more PV cells  105  can be coupled directly to the one or more devices  106  (e.g., a power consuming device or a load) via a switch  135 . In this regard, when the power consuming device is coupled to the one or more PV cells  105 , then the Tx  101  can operate as both a transmitter and a receiver. 
     Turning now to  FIG.  2   , a diagram  200  of one or more devices  201  associated with a wireless power unit is depicted in accordance with one or more embodiments. Examples of the devices  201  include, but are not limited to battery cells and power consuming device. Note that the devices  201  can be connected to a wireless power unit that can operate as a transmitter and/or a receiver. For brevity and ease of explanation, items of  FIG.  1    that are the same or similar are reused in  FIG.  2   . 
     The wireless power unit includes a coil  110  connected to a resonant capacitor  115 . The coil  110  and capacitor  115  are connected to a bridge  210  that can operate as a rectification bridge (i.e., when the wireless power unit operates as a receiver) or as full bridge driver (i.e., when the wireless power unit operates as a transmitter). According to one or more embodiments, the bridge  210  can be composed of four FET devices  220  that are switched to achieve a desired operation mode (e.g., the transmitter and/or receiver modes). 
     When the wireless power unit is in the receiver mode, an output of the rectification bridge (e.g., the bridge  210 ) is connected to a stabilization capacitor  230  and to output switches (e.g., a multiplexer (MUX)/switch  240 ). The multiplexer (MUX)/switch  240  further connects the devices  201  to the bridge  210  and the stabilization capacitor  230 . According to one or more embodiments, when the wireless power unit is in the receiver mode, the wireless power unit can include a switch connecting a detuning capacitor to the coil  110  and the resonance capacitor  115 . The switch can be closed to detune the circuit, reduce the output voltage of a rectifier (e.g., of the bridge  210 ), and control output to the devices  201  (e.g., a battery). In some cases, a output switch to the battery can be omitted (i.e., for two way transfer). 
     When the wireless power unit is in the receiver mode, a driver (e.g., of the bridge  210 ) uses the stabilization capacitor  230  to stabilize a DC voltage supplying power to the full bridge and eventually transmitted via the coil  110 . 
     Ancillary load  250  can be connected or disconnected from the resonance circuit (e.g., the capacitor  115  and the coil  110 ) or from a rectified output of the bridge  210 . The ancillary load  250  can includes one or more resistors, capacitors, or combination thereof. A connection of the ancillary load  250  can be controlled via a FET  260 . The ancillary load  250  can be used for various implementations such as, in-band modulation, minimal load, tuning or detuning of the resonant tank, etc. 
     A controller  125  can be connected to the bridge  210  to control operations therein. The controller  125  can also be connected to individual battery cells (e.g., the devices 201) and can measure voltage and charging/discharge currents thereof. According to one or more embodiments, the controller  125  can be connected to a battery pack via digital interface, such as system management bus, and can probe battery voltage and currents via the digital interface. The controller  125  can also monitor voltage of the resonance circuit (e.g., capacitor voltage of the capacitor  115  and inductor voltage of the coil  110 ) as well as AC currents on the resonance circuit (e.g., by measuring of voltage of resistive element, via capacitor voltage derivation, current transformer, etc.). The controller  125  can also control the ancillary load  250  and the FET  260  to modulate load and send data from a receiver to a transmitter. 
       FIG.  3    depicts a method  300  in accordance with one or more embodiments. The method  300  can be embodied by the firmware  127  and executed by the controller  125   116 . Generally, the method  300  is an implementation of initially operating to achieve constant current charge to the battery pack  107 . For brevity and ease of explanation, items of  FIGS.  1 - 2    that are the same or similar are reused in  FIG.  3   . 
     The method  300  begins when the Tx  101  starts an initial connection to the Rx  102 . As shown in at block  310 , the Tx  101  starts a connection with the Rx  102 . The Rx  102  may operate to implement a CCCV charging algorithm to a battery (i.e., the battery pack  107 ) connected to the Rx  102  or may implement fixed voltage output algorithm. A control over a power level of the Rx  102  can be implemented through a control of transferred power from the Tx  101  by the Rx  102  sending commands to the Tx  101 . In this regard, at sub-blocks  314  and  318 , the Tx  101  can operate drivers therein at specific frequency (e.g., a target point as defined or set by the firmware  127 ) and at a duty cycle provide enough induced voltage on the Rx  102  for the Rx  102  to start operation. The target point defined or set by the firmware  127  can include, but is not limited to, a set power level or a maximum power. The induced voltage can be selected at along a range of 5-10 volts. The induced voltage can be below a voltage level (e.g., 20-25 volts) required to charge the battery pack  107 , so that the Rx  102  refrains from a current flow to the battery pack  107  (at this stage). 
     The method  300  can continue through Path A or Path B, for example, according to operations of the controller  125 , signals/commands sent to the Tx  101  by the Rx  102 , and/or based on reaching the Tx  101  reaching an operation point. With respect to Path A and block  320 , the Rx  102  signals the Tx  101  to increase a power level, as required until reaching a desired voltage for reaching a predefined charge current level. Note that, when in the constant current portion of the CCCV charge cycle, the Rx  102  checks to determine if there is enough voltage to charge the battery pack  107 . Note also that, when in the constant voltage portion of the CCCV charge cycle, the Rx  102  checks to determine the fixed voltage level. According to one or more embodiments, if a high current level is set by the firmware  127 , it can be determined that the Tx  101  based on a power capability of the one or more PV cell units  140  may not be able to reach the high current level (e.g., if the PV cells  105  cannot provide enough watts). In this case, the Rx  102  or the Tx  101  can sense that no further increase is possible and switch to the MPPT operation. 
     At block  330 , the Tx  101  increases an amplitude of magnetic field emitted by the coil  110  to increase voltage and power level of the Rx  102 . According to one or more embodiments, increasing the amplitude of the magnetic field by the Tx  101  can be implemented by changing an operating frequency, the duty cycle, and/or (c) an amplitude of a switched DC voltage. 
     At decision block  340 , the Tx  101  tests whether a set power level or the maximum power is reached. That is, once the target point is reached, the Tx  101  transfers to MPPT operation (as shown by the YES arrow). In the MPPT mode of operation, the operation point is modified based on internal feedback, as well as feedback from the Rx  102 . If the target point is not reach, the method return to block  320  (as shown by the NO arrow). 
     With respect to Path B and block  350 , the Tx  101  initiates the MPPT operation (e.g., the Tx  101  goes directly to MPPT operation as described herein). 
       FIG.  4    depicts a method  400  in accordance with one or more embodiments. The method  400  can be embodied by the firmware  127  and executed by the controller  125   116 . Generally, the method  400  is an implementation of the MPPT operation. For brevity and ease of explanation, items of  FIGS.  1 - 3    that are the same or similar are reused in  FIG.  4   . 
     The method  400  beings at block  410 , where the controller  125  of the Tx  101  measures transferred power level. In an example, the controller  125  can measure a DC voltage and a current from the PV cell units  140  to the bridge  210 . During this time, the Rx  102  can send the Tx  101  notifications. For instance, the Rx  102  can send a decrease notification. In this regard, the Tx  101  needs to satisfy whether the receiver needs less power. According to one or more embodiments, the notifications can indicate whether a charging current level exceeds a maximal allowed during constant current operation or whether a voltage is higher than permitted for constant voltage operation. Further, the notifications can be in a form of an error packet that request a negative change to operation point. 
     At decision block  420 , the Tx  101  determines if the Rx  102  sent the Tx  101  a decrease notification. If yes, the method  400  proceeds (as shown by the YES arrow) to block  440 . At block  440 , the Tx  101  decreases the power. Then, the method  400  returns to block  410 . If no, the method  400  proceeds (as shown by the NO arrow) to block  450 . 
     According to one or more embodiments, once such indication is received from the Rx  102 , the Tx  101  stops attempting to increase power level and slightly reduces power level (i.e., by increasing or decreasing duty cycle depending on direction of change). The Tx  101  can resume attempts to optimize power after a defined delay or on indication from the Rx  102  (or combination of). Further, the indication can be reception of an error packet with a request for zero or positive change to operation point. 
     At decision block  450 , the Tx  101  determines whether the power level is higher than the measured power level on previous measurement (such as a previous pass of block  410 ). If yes, the method  400  proceeds (as shown by the YES arrow) to block  460 . If no, the method  400  proceeds (as shown by the NO arrow) to block  470 . 
     At block  460 , the Tx  101  continues a power increase on a same direction. That is, the Tx  101  gradually increases duty cycle or reduces frequency, as long as transferred power increases. Then, the method  400  returns to block  410  so that the power level can be measured again (e.g., checks to make sure operations are successful). 
     At block  470 , the Tx  101  switches direction and continues a power increase. Then, the method  400  returns to block  410  so that the power level can be measured again (e.g., checks to make sure operations are successful). For example, the Tx  101  reverses a direction and starts to decrease the duty cycle or increase the frequency (i.e., once the transferred power starts going down). Note that the method  400  can loop, such that the Tx  101  can continue doing so as long as power increases, and will switch back if the power decreases. 
     According to one or more embodiments, measurements and decisions by the controller  125  are performed with delay from a duty cycle/frequency change to accommodate a settling time of the wireless PV power system (e.g., a duration of settling time can be determined by value of capacitance on the Rx  102  and the Tx  101 ). 
     According to one or more embodiments, the Tx  101  can halt modifications to duty cycle or frequency for a defined period of time, if maximal point is reached. 
     According to one or more embodiments, additional notifications/messaging/communications can be used to indicate a change in charge mode, a start/end of charging, a battery charge state, a temperature, etc. The controller  125  can any notifications/messaging/communications to modify an operation point. 
       FIG.  5    depicts a method  500  in accordance with one or more embodiments. Generally, the method  500  describes burst mode operation of the bridge  210  by the controller  125  of the Tx  101 . In this regard, at block  520 , the bridge  210  operates and provides alternate voltage for a specific time period (i.e., an On period). At block  540 , the bridge  210  halts and does not provide voltage drive for a second time period (i.e., an Off period). The burst duration (e.g., a total of the On and Off periods) can be determined by the controller  125  to not significantly discharge the Tx  101  capacitance during the On period of a cycle. According to one or more embodiments, the total durst duration can include a 1.5 milliseconds cycle, with the On period being 300 microseconds. 
     One or more technical effects, advantages, and benefits of the wireless PV power system operating in a burst mode include, but are not limited to system efficiencies. In this regard, the PV cells  105  may be limited to a certain power level (e.g., in an exemplary implementation, limited to 5 watts power level), while a transfer efficiency is higher for higher power levels (e.g., 25 watts). By leveraging the burst mode operation, the Tx  101  of the wireless PV power system operates at transfer power of 25 watts when active, while providing an average transfer power of 5 watts that can be supplied by the PV cells  105 . Further, capacitors of the Tx  101  can fill up from the PV cell  105  (i.e., stall energy when not transmitting), and then empty to the Rx  102  at a much higher efficiency. The burst mode operation requires the controller  125  to provide a strict timing operation to satisfy requirements of the wireless PV power system. 
     Further, according to one or more embodiments, a capacitance of the Tx  101  can be set to accommodate the burst duration and to maintain a minimal voltage reduction during that period. In terms of the transmitted power stability, the Tx  101  can ompensate for the voltage reduction during the burst duration by increasing duty cycle as the On period progresses. 
     By way of example, the burst duration can be set to 1.5 milliseconds, the controller  125  can assume 25 watts of power is be transmitted during the On period, the PV cell  105  is supplying a 5 watt, and the On period can be 300 microseconds. In this case, a PV optimal voltage can be 18 volts, with an overall ripple of a 1 volt max being achieved, while capacitance can be required according to Equation 1. 
     
       
         
           
             
               
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     According to one or more embodiments, MPPT optimization is available during the burst mode operation. When multiple PV cells  105  are used, the controller  125  can initiate multiple power transfer bursts. In this regard, on each burst, one of the PV cells  105  is connected to bridge to supply power for transmission via a relevant storage capacitor. Further, an optimization of voltage can be performed for each PV cell  105  individually. IN this case, the method  500  can still be applied, while tracking of any transferred power is performed for each of the bursts and respective PV cells  105 , separately. 
     According to one or more embodiments, the burst mode operations can cause some jumps on a voltage of the bridge  210 , when switching operations between PV cells  105 . Yet, given a capacitance connected directly to the bridge  210  is relatively small compared to an individual capacitance of the PV cell  105  and given an overall charge transferred in a single burst, any losses due to these switches are going to be relatively low. 
     According to one or more embodiments, the burst mode operations can include an alternative communication scheme between the Tx  101  and the Rx  102  (in contrast to a continuous mode). For instance, communications from the Rx  102  to the Tx  101  may need to be adjusted during the burst mode operations. In a communication scheme, the Rx  102  to the Tx  101  communication can use messages that include 10 s of bits and that last 10 s of milliseconds. Note that wireless power consumption (WPC) message requires 44 bits and 22 milliseconds of transmission time, which are relatively long bit times. In improving and updating the communication scheme, the wireless PV power system can stop the bursts to communicate (e.g., no communication during the bursts). In this regard, because bursts are shorter than non-burst time periods and because the burst mode operation can be activated after an initial negotiation between wireless PV power system operating (e.g., the initial negotiation can set an initial operational point), an amount of data exchanged during the burst mode operation can be minimal and composed of very few data bits. In turn, the controller  125  can use short pulse patterns that can be synchronized to power carrier cycles. Note that set of patterns can being be unique and orthogonal to each other (i.e., a match filter for one of the patterns yields a 0 for the others). Further, the short pulse patterns length can be shorter than the On period of the cycle. 
     According to one or more embodiments, the Tx  101  combines and implements standard power control for the load and MPPT operations/algorithms with the one or more PV cell units  140 . Further, the Rx  102  simultaneously operates CCCV operations/algorithms or other operations/algorithms to control battery charging and enables MPPT operations/algorithms of the one or more PV cell units  140 . Note that the MPPT operations/algorithms can be characterized by switching a direction of a control by the controller  125  of the Tx  101  to determine a maximal power point. 
     According to one or more embodiments, the Tx  101  operates at bursts to improve power efficiency of transfer. The Tx  101  can further switch between burst operations and continuous operations based on a power state of the one or more PV cell units  140  or a state of the Rx  102 . The Rx  102  can initiate burst mode operations by sending a request (e.g., a specific request) to the Tx  101 . The specific request can define a burst length or a number of bursts. The Tx  101  and/or the Rx  102  can perform burst mode operations while maintaining MPPT operations/algorithms. 
     According to one or more embodiments, a pattern of 8 bits can be sent by the controller  125 . Examples of the pattern of 8 bits can include, but is not limited to, 0xAA, 0x33, 0x0F, and 0x00, where each codes a different message. For instance, each of these patterns can code to a voltage/current threshold has been reached, a charge is complete, a charge is stopped, and a charge ongoing. Each bit can be sent over a defined number of carrier cycles (e.g., four cycles). For instance, a transmission can last over 32 carrier cycles, which may take a total of 256 microseconds if a carrier frequency of 125 kilohertz is used. 
     According to one or more embodiments, a ‘1’ bit can be sent by activating the ancillary load  250 , while a ‘0’ bit can be sent by disabling the ancillary load  250 . The controller  125  can implement similar coding schemes to derive similar functionality for other elements of the wireless PV power system. 
     According to one or more embodiments, a match filter for each of one or more filters may be derived based on training sequence at start of burst mode operations. The Rx  102  can send each of the patterns at a known order, allowing the Tx  101  to ‘learn’ an expected reception signal for each of the transmitted signals. In this way, the wireless PV power system can employ different modes of operation and dynamically switch therebetween. 
     According to one or more embodiments, no communication is performed during the bursts. The Tx  101  or the Rx  102  initiates burst mode operations indicating the interval (i.e., burst length) or number of bursts to be initiated. At the end of a burst period, the Tx  101  resume/continues operation. The Rx  102  can then communicate with the Tx  101  using a non-burst mode communication protocol to signal if a change to an operation point is required or if burst mode operations can be resumed for another interval. 
     According to one or more embodiments, the Rx  102  can initiate burst mode operations by sending a dedicated burst request packet (e.g., a specific requests). The packet includes the number of bursts to be initiated, were the On and Off periods of each bursts are pre-configured at the Tx  101  and the Rx  102 . The Tx  101  can initiate a number of defined bursts, as in the received packet. When a burst interval is completed, the Tx  101  can resume/continues operation. The Rx  102  monitors power, current, and/or voltage during the burst period. The Rx  102  can initiate an error packet if a value is outside a desired range, if the value is within a required window, and resend a burst request packet to initiate another burst interval. 
     According to one or more embodiments, the wireless PV power system can select to enter or exit burst mode operations according to a state of the one or more PV power sources or the PV cells including, but not limited to, a maximal power currently achievable by the one or more PV power sources or PV cells or by a load level or charging phase of the Rx  102  and an ability of the Tx  101  to satisfy this load level. In an exemplary implementation of the wireless PV power system, the Rx  102  initiates the burst mode operations when the Rx  102  attempts to request an increase of power level but does not get an actual increase of power for a defined period of time. In an exemplary implementation of the wireless PV power system, the Rx  102  requests the burst mode operations when entering constant current (CC) phase of battery charging and exists the burst mode operations when moving to constant voltage (CV) phase of charging. 
     According to one or more embodiments, the wireless PV power system provides a ‘standby’ mode of operation enabling a power consuming device (e.g., the one or more devices  106 ) to be powered at very low power consumption from the one or more battery packs  107 . Further, the wireless PV power system can provide/maintain an efficient operation vs. a ‘full power’ mode of operation to provide higher power levels to the consumer. In efficient operation, the controller  125  on the power consuming device side of the wireless PV power system signals the Tx  101  on the battery pack  107  that a lower voltage level is to be delivered (e.g., instead of a voltage used for ‘full power’ operation). The signaling can be based on continued feedback of power increase/decrease commands that set the Tx  101  to an operation point that provides a low voltage level on the Rx  102 , or by signaling for a standby mode as part of initial signaling. The standby mode causes the Tx  101  to set an operational point, accordingly, to meet the lower voltage requirement. The Tx  101  can also initiate burst mode operations to minimize power consumption. 
     According to one or more embodiments, the wireless PV power system can revert between different modes of operation (i.e., battery charging, consumer full power driving, consumer standby driving, and others described herein) based on a consumer and PV cells state. If a current state is that a battery operates as a Tx and the controller  125  determines to move to an off mode or a battery charging mode (e.g., were the controller  125   becomes the Tx  101 ), the controller  125  sends a terminate charge message to the battery pack  107 . Once a power carrier is removed, the controller  125  can operate as a Tx or shut down (according to desired mode). If a current state include that the controller  125  operates as a Tx or is not active, and the controller  125  requires to move to a standby mode or a full power, the controller  125  can first terminate a Tx mode (if active) by shutting down power carrier, and then close the bridge  210  to provide a short of the resonance circuit. This short indicates to the controller on other side that power transfer is required. If the controller  125  moves to Off state, the controller  125  will terminate Tx operation if active and leave the bridge  210  open to have the resonance circuit in open circuit state. 
     According to one or more embodiments, the wireless PV power system can provide a role reversal. In this case a battery side controller operates in Rx mode, while waiting for ‘digital ping’ (i.e. a carrier activation from the other side). If the battery side controller is not in a power transfer phase, battery side controller can perform a periodic analog ping by sending a pulse or train of pulses on a bridge therein and measure a bridge voltage decay. The battery side controller can distinguish if there is a shorted circuit on the other side, and if so, the battery side controller can revert to operate as a Tx and initiate power transfer. The battery side controller can cease Tx operation when receiving a terminate charge message from the other side. 
     According to one or more embodiments, the wireless PV power system can enable the battery side controller to start operations in listen mode. The listen mode includes when the battery side controller waits for a power carrier signal on a rectifier therein. If the battery side controller does find the power carrier signal, the battery side controller initiates analog pings to detect a receiver. Further, the battery side controller can initiate transmitter operations if a receiver is detected. If no receiver is detected or no engagement achieved, the battery side controller can revert back to a listening mode. If during the listening mode, the battery side controller detects a carrier, the battery side controller can revert to a receive operation. Similar logic can also be applied by the Tx  101 , with compensation for different timing constraints. 
       FIG.  6    depicts a system  600  in accordance with one or more embodiments. The system  600  has a device  601  (e.g., the Rx  102  and/or the Tx  101  of the system  100  of  FIG.  1   ) with one or more central processing units (CPU(s)), which are collectively or generically referred to as processor(s)  602  (e.g., the controller  125  of  FIG.  1   ). The processors  602 , also referred to as processing circuits, are coupled via a system bus  603  to system memory  604  and various other components. The system memory  604  can include a read only memory (ROM), a random access memory (RAM), internal or external Flash memory, embedded static-RAM (SRAM), and/or any other volatile or non-volatile memory. For example, the ROM is coupled to the system bus and may include a basic input/output system (BIOS), which controls certain basic functions of the device  601 , and the RAM is read-write memory coupled to the system bus  603  for use by the processors  602 . 
       FIG.  6    further depicts an I/O adapter  605 , a communications adapter  606 , and an adapter  607  coupled to the system bus  603 . The I/O adapter  605  may be a small computer system interface (SCSI) adapter that communicates with a drive and/or any other similar component. The communications adapter  606  interconnects the system bus  603  with a network  612 , which may be an outside network (power or otherwise), enabling the device  601  to communicate data and/or transfer power with other such devices (e.g., such as the Tx  101  connecting to the Rx  102 ). A display  613  (e.g., screen, a display monitor) is connected to the system bus  603  by the adapter  607 , which may include a graphics controller to improve the performance of graphics intensive applications and a video controller. Additional input/output devices cab connected to the system bus  603  via the adapter  607 , such as a mouse, a touch screen, a keypad, a camera, a speaker, etc. 
     In one embodiment, the adapters  605 ,  606 , and  607  may be connected to one or more I/O buses that are connected to the system bus  603  via an intermediate bus bridge. Suitable I/O buses for connecting peripheral devices such as hard disk controllers, network adapters, and graphics adapters typically include common protocols, such as the Peripheral Component Interconnect (PCI). 
     The system memory  604  is an example of a computer readable storage medium, where software  619  can be stored as instructions for execution by the processor  602  to cause the device  601  to operate, such as is described herein with reference to  FIGS.  1 - 5   . In connection with  FIG.  1   , the software  619  can be representative of firmware  127  for the Tx  101 , such that the memory  604  and the processor  602  (e.g., of the controller  125 ) logically provide a FIR equalizer  651 , an analyzer  652  of in-band communication data, a selector for selecting a ping, a coupler  653  for dynamically determining a coupling factor, a regulator  654  for dynamically determining an operating frequency, etc. 
     According to one or more embodiments, a wireless photovoltaic power system is provided. The wireless photovoltaic power system includes one or more photovoltaic cell units that provide power. Each of the one or more photovoltaic cell units that include a photovoltaic cell. The wireless photovoltaic power system includes a first wireless power device that receives the power. The wireless power device includes a coil that provides a magnetic field to wirelessly transfer the power to a second wireless power device. The first wireless power device provides a combinational implementation of a maximum power point tracking of the one or more photovoltaic cell units and a power control of a load. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, the wireless photovoltaic power system can include the second wireless power device that engages the magnetic field to generate the second power. The second wireless power device can provide constant current constant voltage operations to control a battery charging. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, the first wireless power device or the second wireless power device can perform burst mode operations while the maximum power point tracking is maintained in the wireless photovoltaic power system. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, the maximum power point tracking of the one or more photovoltaic cell units can include switching a direction of a control by a controller of the first wireless power device to determine a maximal power point. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, the first wireless power device can operate at bursts to improve power efficiency of the transfer of the power. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, the first wireless power device can switch between burst operations and continuous operations based on a power state of the one or more photovoltaic cell units or a state of the second wireless power device. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, the second wireless power device can initiate burst mode operations by sending a specific request to the first wireless power device. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, the request can define a burst length or a number of bursts. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, each of the one or more photovoltaic cell units can include at least a capacitor that smooths out power generated by the corresponding photovoltaic cell. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, each of the one or more photovoltaic cell units can include a switch configured to connect the one or more photovoltaic cell units to the first wireless power device. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, the one or more photovoltaic cell units can connect to the first wireless power device in parallel. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, each of the one or more photovoltaic cell units can be separately connected to and controlled by a controller of the first wireless power device. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, the first wireless power device can be couple the one or more photovoltaic cell units directly to one or more power consuming devices via a switch. 
     According to one or more embodiments or any of the wireless photovoltaic power system embodiments herein, the first wireless power device can operate in a receiver mode. 
     According to one or more embodiments, a wireless photovoltaic power system is provided. The wireless photovoltaic power system includes a wireless power transmitter-receiver that includes a coil configured to provide a magnetic field to wirelessly induced power. The wireless photovoltaic power system includes one or more photovoltaic cell units that provide power to the wireless power transmitter-receiver. Each of the one or more photovoltaic cell units include a photovoltaic cell. 
     According to one or more embodiments of any of the wireless photovoltaic power system embodiments herein, each of the one or more photovoltaic cell units comprises at least a capacitor configured to smooth out power generated by the corresponding photovoltaic cell. 
     According to one or more embodiments of any of the wireless photovoltaic power system embodiments herein, each of the one or more photovoltaic cell units can include a switch configured to connect the one or more photovoltaic cell units to the wireless power transmitter-receiver. 
     According to one or more embodiments of any of the wireless photovoltaic power system embodiments herein, the one or more photovoltaic cell units can be connected to the wireless power transmitter-receiver in parallel. 
     According to one or more embodiments of any of the wireless photovoltaic power system embodiments herein, each of the one or more photovoltaic cell units can be separately connected to the wireless power transmitter-receiver and controlled by a controller of the wireless power transmitter-receiver. 
     According to one or more embodiments of any of the wireless photovoltaic power system embodiments herein, the wireless power transmitter-receiver can be configured to couple the one or more photovoltaic cell units directly to one or more power consuming devices via a switch. 
     According to one or more embodiments of any of the wireless photovoltaic power system embodiments herein, the wireless power transmitter-receiver can be configured to operate in a receiver mode. 
     According to one or more embodiments of any of the wireless photovoltaic power system embodiments herein, the wireless power transmitter-receiver can be configured to operate in a burst mode. 
     According to one or more embodiments of any of the wireless photovoltaic power system embodiments herein, the wireless power receiver can include a driver, a resonance capacitor, and a rectification capacitor. 
     As indicated herein, embodiments disclosed herein may include apparatuses, systems, methods, and/or computer program products at any possible technical detail level of integration. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a controller to carry out aspects of the present invention. 
     The computer readable storage medium can be a tangible device that can retain and store computer readable program instructions. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. 
     The computer readable program instructions described herein can be communicated and/or downloaded to respective controllers from an apparatus, device, computer, or external storage via a connection, for example, in-band communication. Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, configuration data for integrated circuitry, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++, or the like, and procedural programming languages, such as the “C” programming language or similar programming languages. In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. 
     The flowchart and block diagrams in the drawings illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the flowchart and block diagrams in the drawings. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. 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. It will be further understood that the terms “comprises” and/or “comprising,” 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 more other features, integers, steps, operations, element components, and/or groups thereof. 
     The descriptions of the various embodiments herein have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.