Simultaneous independent wireless power and data transfer, time shared as part of power switching cycles

Abstract

Disclosed herein is a system for wireless power and data transfer that uses the same inductively coupled coils for both power transmission and data communication. During a first portion of each switching cycle, power is transferred from a primary-coil to a secondary-coil by operating switches coupled to the primary-coil. During a second portion of the same switching cycle, data is communicated between the primary and secondary coils. Data communication from the secondary-coil to the primary-coil is accomplished by discharging a capacitor through the secondary-coil to generate detectable pulses in the primary-coil. Data communication from the primary-coil to the secondary-coil is accomplished by operating the switches coupled to the primary-coil to generate detectable pulses in the secondary-coil. As a non-limiting example, the first portion of the switching cycle may form 70% of each switching cycle, with the remaining 30% being used for data communication.

Description

[0001] Attorney Docket: WLM-511208-WO-1

[0002] SIMULTANEOUS INDEPENDENT WIRELESS POWER AND DATA TRANSFER, TIME SHARED AS PART OF POWER SWITCHING CYCLES

[0003] TECHNICAL FIELD

[0004] This disclosure relates to wireless power transfer systems, and specifically to systems and methods for using the same set of inductively coupled coils for both power transfer and bidirectional data communication functions.

[0005] BACKGROUND

[0006] Wireless power and data transfer systems are widely utilized for monitoring and controlling equipment deployed within wellbores drilled into subsurface formations to facilitate hydrocarbon extraction, particularly for communication across the casing with sensors installed at B annulus (e.g., behind the casing) where traditional wired connections are not feasible. While surface-to-downhole communication typically relies on tubing-deployed electrical cables, communication across B annulus and through otherwise inaccessible annular spaces is best done wirelessly for both power and data transfer. These systems are operated in harsh environments and are expected to maintain continuous power supply to downhole equipment and sustain data communication between downhole equipment and surface equipment. Beyond such oilfield operations, wireless power and data transfer systems are also widely utilized in other applications such as consumer electronics, automotive electronics, household appliances, and industrial equipment. Among many applications, "battery charging" requires power transfer in one direction and bidirectional data transfer.

[0007] These systems typically utilize a primary coil connected to a power source, a switching converter in which semiconductor devices operate at frequencies optimized for the specific application, and one or more secondary coils inductively coupled to the primary coil. While power may need to be transferred from the primary coil to the secondary coil only in one direction, data communication may occur bidirectionally. Indeed, in many applications, together with power transfer from primary to secondary to power a device or battery connected to the secondary, data is transferred from the secondary to the primary to facilitate monitoring of parameters such as charge percentage, battery health, etc.

[0008] Known approaches for concurrent power and data transfer typically rely on either separate primary and secondary coil sets dedicated to power transfer and data transfer, or on modulation and demodulation of power and data signals sent via the same coil set.

[0009] The use of separate coil sets require additional space and circuitry, in many applications, space constraints make the use of separate coil sets impractical. Other concerns such as maximum feedthrough restrictions and electromagnetic interference may also preclude the use of multiple WLM-511208-WO-1 1Attorney Docket: WLM-511208-WO-1 coils. These constraints are particularly acute in downhole operations where space is rather limited and environmental conditions are severe. In addition, wireless power and data communication needs to be established through thick metal casing. This results in very poor coupling between primary and secondary coil, for example the coupling could be as little or below 5%. The thick steel casing results in huge eddy current loss. Both factors, inadequate coupling and eddy current loss results in poor power and data transfer efficiency.

[0010] Modulation / demodulation techniques involve additional complex circuitry that may reduce further data transfer rates and system efficiency while increasing manufacture costs. In greater detail, when using a single coil set together with modulation / demodulation techniques, transferring both power and data signals involves a variety of potential issues. For example, the switching frequency of the alternating excitation to facilitate power transmission needs to be substantially higher than the communication frequency utilized for modulation / demodulation, which may not be feasible in certain applications where the fundamental switching frequency is set as per system requirements to minimize eddy current loss and power transfer considerations. In such situations, even more complex modulation and demodulation circuitry that limits bandwidth while adding complexity and cost would be required.

[0011] The above-described challenges create a need for more efficient and compact approaches for combined power and data transfer across wireless boundaries.

[0012] SUMMARY

[0013] Disclosed herein and addressing the issues described above is a wireless power and data transfer system that uses the same set of inductively coupled coils for both power transmission and bidirectional data communication, eliminating the need for separate communication coils and associated circuitry. The system operates by time-sharing the coils between power transfer and communication phases within each switching cycle, where power is transferred from a primary side to the secondary side during a power transfer phase, and bidirectional data communication occurs during a communication phase using the same coils. The primary side includes switching circuitry to effectuate power transfer and enable data transmission, while the secondary side includes rectification circuitry and data communication circuitry that enables transmission of monitored parameters or other data back to the primary side through the shared coils. This approach reduces system complexity and cost while enabling reliable power and data transfer even with axial misalignment between components, making it suitable for various applications where wireless power and data transfer are required.

[0014] BRIEF DESCRIPTION OF THE EMBODIMENTS FIG. 1 is a schematic diagram of a wireless power and data transfer system described herein.

[0015] WLM-511208-WO-1 2Attorney Docket: WLM-511208-WO-1 FIG. 2 is a graph showing voltages of the wireless power and data transfer system of FIG. 1 during the data communication phase of a cycle.

[0016] FIG. 3 illustrates how the power pulse's first rising edge serves as a trigger for generating delays in data generation and detection windows for both primary and secondary sides, while demonstrating how a portion of the power transfer cycle can be modified for primary-to-secondary data transfer, thereby enabling independent power and data transfer operations.

[0017] FIG. 4 is a schematic diagram of an embodiment of a wireless power and data transfer system described herein amenable to a large variety of applications.

[0018] DETAILED DESCRIPTION

[0019] The following disclosure enables a person skilled in the art to make and use the subject matter described herein. The general principles outlined in this disclosure can be applied to embodiments and applications other than those detailed above without departing from the spirit and scope of this disclosure. It is not intended to limit this disclosure to the embodiments shown, but to accord it the widest scope consistent with the principles and features disclosed or suggested herein.

[0020] The wireless power and data transfer system 5 is now described with reference to FIG. 1, and includes primary side circuitry 10 associated with a production tubing string and secondary side circuitry 20 associated with a downhole casing string, wherein the primary and secondary side circuitry may be disposed on interior surfaces, exterior surfaces, or within walls of their respective strings.

[0021] In most cases the available power is DC, through the tubing encapsulated cable line (TEC). A nominal TEC voltage can be anywhere between 10 V to 700V DC, and the required power is low voltage DC for digital circuits and sensors. The task is essentially to design an isolated version of switched mode DC to DC converter and then use the same coils for data transfer. The tubing coil, instead of being supplied by a traditional alternating voltage, is part of a switched mode converter as the primary side coil and the secondary is the casing coil. In the simplest implementation of the switched mode converter, the primary side coupled inductor (coil) is charged and discharged, and power is extracted from the secondary side coupled inductor (coil).

[0022] The primary side circuitry 10 is excited from a power source 11 (for example, 24 V de, however it could be any de or ac voltage or current source) through the tubing encapsulated cable (TEC), connected and taking power from the surface, indicated as PWR and a reference voltage GND (which in some applications could be virtual ground coming from the tubing chassis), a controller 12, and a primary coil Lp connected between nodes N1 and N2. Node N1 is coupled to receive the power signal PWR through switch S1 , and N2 is coupled to the reference voltage GND through switch S2. The controller 12 has inputs connected to N1 and N2 (e.g., across the primary coil Lp) for receiving data pulses and controls the switches S1 and S2 for power transfer. The primary side circuitry 10 further includes a diode D3 having its cathode connected to receive the power signal WLM-511208-WO-1 3Attorney Docket: WLM-511208-WO-1 PWR and its anode connected to node N2, and a diode D4 having its cathode connected to node N1 and its node connected to ground. This embodiment depicts a standard two switch forward converter, but it should be appreciated that the wireless power and data transfer system 5 may be adapted to other switching converter topologies, such as flyback, push-pull, or other suitable switching converter topologies.

[0023] The secondary side circuitry 20 includes a secondary coil Ls connected between nodes N3 and N4, and a diode D1 having its anode connected to node N3, with the load 22 (e.g., a rechargeable battery or additional switched mode DC power converter powering downhole monitoring equipment such as pressure sensors, temperature sensors, flow meters, or other wellbore condition monitoring devices) being connected between the cathode of diode D1 and node N4, and a capacitor C1 being connected between the cathode of diode D1 and node N4. A battery may provide continuous power to permanent downhole monitoring systems, completion components, downhole control devices, or other equipment requiring sustained operation in the wellbore environment. The battery may or may not be present, but if present, the battery charging circuit forms the effective load. In the absence of a battery the capacitor C1 holds the charge to power the downhole monitoring equipment.

[0024] The secondary side circuitry 20 further includes data communication circuitry 25 that, under control of the controller 21 as will be described below, transmits data to the primary side circuitry 10.

[0025] The data communication circuitry 25 includes a diode D2 having its anode connected to node N3 and its cathode connected to a first terminal of capacitor C2, with a second terminal of capacitor C2 being connected to node N4.

[0026] Bidirectional wireless data communication includes two data transfer modes: a) tubing to casing communication, and b) casing to tubing communication. As the tubing side is connected to the power source (through TEC), it is easy to create additional communication pulses at the end of power transfer fraction of the switching cycle. Data transmission from the primary side circuitry 10 to the secondary side circuitry 20 may be accomplished by operating switches S1 and S2 during the communication phase to create voltage patterns across Lp that represent data and are inductively coupled to Ls. These pulses are detectable at N3 on the casing (secondary) side. Any detection circuitry, rising or falling edge and any appropriate token logic would then be able to detect these pulses reliably even for a very low coupling and a highly lossy transfer barrier. In most practical applications, tubing to casing communications includes establishing a trigger or synchronization pulse that defines the time window of expected casing to tubing data interval. The start of the power transfer pulse could be used for this, and in this case no addition data pulse may be needed. The real challenge in existing conventional designs is the casing to tubing communication.

[0027] Casing to tubing communication is difficult because there is very little power available on the secondary side. The communication could be accomplished by creating a change of impedance on the secondary side by opening or closing semiconductor switches on the secondary side, and creating a change of equivalent impedance as measured from the primary side, however for low WLM-511208-WO-1 4Attorney Docket: WLM-511208-WO-1 coupling situation the change observed from the primary side would be insignificant. Thus, no reliable communication could be established by this technique. Instead, an alternative, reliable and novel technique disclosed herein has been developed -- an active voltage pulse is created on the secondary side, representing a data bit for casing to tubing communication. This is accomplished by extracting part (fraction) of the power in the power transfer cycle and storing it in a different capacitor C2, which can be referred to as the auxiliary capacitor. During the power cycle the auxiliary capacitor C2 is charged. When the data pulse needs to be created, the controller 21 turns on the transistor T2 to create a voltage (data) pulse at N3 representing casing to tubing communication. Thus, the wireless power and data transfer system 5 performs both power transfer and data communication phases using the same set of inductively coupled coils (Lp and Ls), eliminating the need for separate power and communication coils and complex modulation circuits.

[0028] During the power transfer phase of each switching cycle, controller 12 operates switches S1 and S2 to generate switching cycles that effectuate power transfer. During the first portion of the cycle (as a non-limiting example, 35%), switches S1 , S2 are ON, during which current flows from the power source 11 through S1 and S2, primary coil Lp, inducing voltage in the secondary coil Ls. Subsequently (as a non-limiting example, during next 35% of the cycle), When S1 and S2 are turned OFF the coupled inductor Lp in the primary discharges, and diodes D3 and D4 provide a discharge path for the primary inductor Lp, the discharge time varying based on circuit conditions and losses. Though in this example 35% is used as primary inductor charging time, 35% is used as primary inductor discharging time, and 30% is used as data communication time, the discharge time may be much less than 35%, with this being determined by the system based on the losses and 35% being an example maximum limit. As a positive consequence, this would allow more time for data transfer. The induced voltage is rectified by diode D1 to charge capacitor C1 and provide power to the load 22, as well as by diode D2 to charge capacitor C2.

[0029] The remaining portion of each cycle (as a non-limiting example, 30%) is used for data communication between the primary side circuitry 10 and secondary side circuitry 20. The ratio between power transfer and data communication periods can be dynamically adjusted by the controller 12 based on system requirements. When the load 22 demands less power, the power transfer period could be reduced while expanding the data communication window. Conversely, when higher power transfer is needed, the power phase could be increased while maintaining a smaller communication window. This flexibility allows the system to optimize the balance between power delivery and data bandwidth based on real-time conditions.

[0030] During the data communication phase, switches S1 and S2 are in their inactive states, and the switch S3 creates the casing to tubing data pulse in response to the command from controller 21. The data pulse is transmitted back to the primary side using the same coupled coils Lp and Ls that were used for power transfer. The components of the data communication circuitry include a PNP transistor T1 having its collector connected to node N3, its emitter coupled to the cathode of diode D1 through resistor R1, and its base coupled to the collector of NPN transistor T2 through WLM-511208-WO-1 5Attorney Docket: WLM-511208-WO-1 resistor R2. The emitter of NPN transistor T2 is connected to node N4 and the base of NPN transistor T2 is coupled to receive output from the controller 21 through resistor R3. Resistor R4 and capacitor C3 are connected in parallel between the base of NPN transistor T2 and node N4.

[0031] When controller 21 provides sufficient base current through R3 into the base of NPN transistor T2, it turns ON, pulling its collector voltage low. This low collector voltage, applied through R2 to the base of PNP transistor T1, creates a current into the base of T1 to turn ON T1, providing a discharge path for 02. The stored charge on 02 discharges through T1 and R1 back into N3, creating the data transfer voltage pulse across the secondary coil Ls, which being inductively coupled to the primary coil Lp, generates a detectable voltage pulse that can be sensed by controller 12 through its connections to nodes N1 and N2.

[0032] When T2 is turned OFF by the controller 21, T1 also turns OFF, interrupting the discharge path of capacitor C2. While only one pulse is shown for illustration, multiple communication pulses could be transmitted during the communication phase. Indeed, to transmit digital data, controller 21 can generate these pulses in predetermined patterns to generate binary Os and binary 1s. Multiple bits can be transmitted during each communication phase by dividing the available time into multiple windows for potential pulse transmission.

[0033] Immediately after the end of data communication phase the next power transfer cycle begins, replenishing C2 through D2, preparing for the next data communication pulse and the cycle then keeps repeating. The situation described here, first part of switching cycle for power and second part for data transfer can be reversed as well. As long as the power is present in the secondary side (suitable power good monitor ICs may be used for this function) it should be able to transfer the data back to the primary even in the first part of the switching cycle.

[0034] While bidirectional or unidirectional data transmission between the primary and secondary sides can occur during the communication phases as described herein above, data communication from primary side circuitry 10 to secondary side circuitry 20 may additionally or alternatively be accomplished during the power transmission phase. This is accomplished by controller 12 modifying the typical switching pattern of S1 and S2 to represent data while maintaining power transfer. For example, the typical 35% ON time of switch S1 can be varied and / or pulsed to create detectable pattern changes in the voltage induced at N3, which can be interpreted as data by controller 21 , while still maintaining sufficient power transfer to the secondary side circuitry 20.

[0035] A graph showing data transmission from the secondary side circuitry 20 to the primary side circuitry 10 is shown in FIG. 2, in which power transmission from the primary circuitry 10 to the secondary circuitry 20 occurs between times TO and T1, and in which data transmission from the secondary circuitry 20 to the primary circuitry 10 occurs between times T1 and T2. The top waveform shows switch SI control signal, which alternates between ON and OFF states during power transmission between times TO and T1. The middle waveform shows the voltage across the coil Lp, which follows the switching pattern during power transmission between times TO and T1. During the signal transmission period between times T1 and T2, a narrow pulse appears on the coil WLM-511208-WO-1 6Attorney Docket: WLM-511208-WO-1 Lp due to the data communication sent by the secondary circuitry 20. The bottom waveform shows the T2 switch drive signal, illustrating how a short 50pS communication pulse is generated, and it should be recognized that the pulse could be of any suitable duration.

[0036] Sample schemes for representing data in bidirectional data communication are now described, with it being understood that other schemes may be used.

[0037] For primary to secondary communication, first described is how the scheduled ON time of power switch S1 can be used to transfer data as well. Returning to the example of 35% SI ON time, the first 20% of the cycle time can be allotted to focus on power transfer, i.e. recharging the casing side capacitors. Then without completely disrupting power transfer S1 can be turned ON / OFF in quick succession to represent data as explained in Fig. 3. Token generation schemes could be any possible pulse scheme, for example one pulse means bit 0 and two successive within a predefined (adjustable) window implies bit 1. Data could be organized by 8 or 16 bit frames, or any bit frames where the end of frame could be absence of tokens over a full fundamental switching cycle. For primary to secondary communication, an alternate scheme could be to wait for the completion of full 35% S1 on time, followed by S1 ON / OFF in quick succession to represent data, again enhancing power transfer as part of data communication. Care is to be taken to not exceed a total 50% ON time for S1. In addition, this scheme reduces the time available for data transfer from secondary to primary.

[0038] For secondary to primary communication, data tokens may be represented as pulses detected after the end of power pulses. Even if there is no intentional communication from tubing to casing the rising edge of the power pulse can always be interpreted as a communication pulse to triggerthe controller 21 on the casing side by commanding it to send data pulse after the completion of power transfer time. In addition, it can also trigger the controller 12 so that it knows when to expect the transmitted data pulse (from casing to tubing) at the end of power cycle. The data could be just one pulse, or multiple pulses all powered by the auxiliary capacitor C2 and started by sending an ON pulse toT2.

[0039] As stated herein above, other schemes may be used. For primary to secondary communication, different pulse patterns, timing windows, token format and end of token definitions could be used to represent binary data, and different frame structures could be implemented based on specific applications. Likewise, for secondary to primary communication, the pulse generation through operation of T1 and T2 could be utilized with different timing parameters, pulse patterns, or frame structures. Regardless of the specific scheme used, the hardware utilized remains unchanged. In addition, the auxiliary capacitor C2 can be replaced by a battery or charge pump as needed for the specific application.

[0040] The wireless power and data transfer system 5 provides multiple advantages through its use of the same inductively coupled coils Lp and Ls for both power and data transfer. This design results in space savings compared to systems requiring separate power and communication coils. Indeed, the elimination of separate coils and their associated modulation and demodulation circuits WLM-511208-WO-1 7Attorney Docket: WLM-511208-WO-1 reduces both cost and complexity while enabling higher bandwidth data communication. Additionally, the system's ability to dynamically adjust the ratio between power transfer and data communication periods provides operational flexibility. The controller can modify this ratio based on load power requirements, battery charge status, data transmission urgency, and overall system efficiency goals. This adaptive timing allows for suitable resource allocation between power delivery and data communication functions.

[0041] Furthermore, using the same coils for both power and signal transfer provides additional advantages in well installations where axial misalignment between components is a common challenge. When multiple primary side coils are implemented for misalignment tolerance, having the same coils handle both power and data transfer greatly simplifies the system. This is because only one primary-secondary coil pair needs to maintain proper coupling for both functions, rather than separate alignments for power and communication coils being required. This allows the system to tolerate greater axial misalignment during installation while maintaining reliable operation.

[0042] It is evident that modifications and variations can be made to what has been described and illustrated herein without departing from the scope of this disclosure.

[0043] While the embodiment above is based on one of specific topologies, the concept of timesharing power and data transfer across the same inductively coupled coils can be implemented across a wide range of power conversion topologies. Indeed, this disclosure covers the cycle-by-cycle time-sharing of power and communication functions across coils that are primarily designed and optimized for power transfer. This approach can be adapted to various switching circuit topologies including, but not limited to, buck converters, boost converters, buck-boost converters, full bridge converters, flyback converters, forward converters, Cuk converters, and derived resonant converters from the fundamental topologies.

[0044] Furthermore, while the described embodiments focus on subsea well monitoring applications, this time-sharing concept for power and data transfer using a single set of coils can be applied across numerous industries and applications where wireless power and data transfer are required.

[0045] Now described with reference to FIG. 4 is an embodiment of the wireless power and data transfer system 5" usable in a large variety of potential applications. This is similar to the circuit shown in FIG. 1 but with further simplification to visualize direct conversion of flyback and forward or other circuit topologies.

[0046] The primary side circuitry 10” includes a power source 11 and a primary coil Lp connected between nodes N1 and N2, with switch S1 being connected between N2 and ground.

[0047] The secondary side circuitry 20“ includes a secondary coil Ls connected between nodes N3 and N4. The controller 21 controls switch S3 within a data communication circuit 25" that includes diode D2 and energy storage device 40 (e.g., a capacitor, a rechargeable battery, a charge pump, etc) series connected between nodes N3 and N4, with the anode of diode D2 being connected to node N3 and energy storage device 40 being connected between the cathode of diode D2 and node N4. Diode D1 has its anode WLM-511208-WO-1 8Attorney Docket: WLM-511208-WO-1 connected to node N3 and its cathode connected to the load, and a capacitor C1 is connected across the load.

[0048] In this circuit the primary coil charging occurs whenever SI is closed, the discharge path is not explicitly shown here, as it can be implemented in many ways. For example, for a very poor coupling, there is an explicit discharge path through additional diode(s) for good efficiency. In operation, this design maintains the core functionality of time-shared power and data transfer across the coupled coils Lp and Ls as described above. Power transfer occurs when switch S1 is operated to induce voltage in Ls, which is then rectified by D1 to charge C1 and power the load 22. During data communication phases, the controller 21 can operate switch S3 to transmit data through the coupled coils, while still using D2 and energy storage device 40 to enable data transmission from secondary to primary through the same magnetic coupling path, and the switch S1 being operated to enable data transmission from primary to secondary.

[0049] This demonstrates how the fundamental principle of time-sharing for power and data transfer using a single set of coils can be adapted to meet different application requirements while maintaining bidirectional data capability. Even if the available power is alternating voltage, the above-described topology could be modified slightly to implement the concept of independent power and data transfer in a time shared fashion in each power cycle through the isolation boundary.

[0050] For example, if the dot in Ls is flipped (meaning the polarity marking of the secondary winding Ls is reversed relative to the primary winding Lp), this would represent a flyback converter topology in which energy is stored in the magnetic field of the coupled windings during the power transfer phase when the primary switch (e.g., SI ) is ON, and then transferred to the secondary side when the switch (e.g., S1 ) turns OFF. This differs from the forward converter topology where power is transferred to the secondary while the primary switch is ON. The flyback topology could also be used for the concept of time sharing power and data transmission across the same primary and secondary coil set, as the fundamental principle of using magnetic coupling for both power and signal transfer operates regardless of the transformer dot convention and the resulting power transfer mechanism. This adaptability to different converter topologies provides flexibility in implementation and renders the wireless power and data transfer system 5" usable in a large variety of applications. The best window for data transfer is when the power transients have died out and the circuit is at its inactive phase, in flyback derived circuits this could be best accomplished in discontinuous mode (DCM). In addition, care needs to be taken in data interpretation based on the relative polarity of the coils (dot positions) in flyback mode.

[0051] Notethat this disclosure is not about the specific circuit or block diagram implementation but rather the concept that the power circuit topology designed for power transfer from primary to secondary is enough for bidirectional data communication, and that this data communication could be established by using part of the switching cycle itself.

[0052] WLM-511208-WO-1 9

Claims

Attorney Docket: WLM-511208-WO-1CLAIMS1. A method comprising:during a portion of a switching cycle, transferring power from a primary coil to a secondary coil through inductive coupling; andduring an additional portion of the same switching cycle, communicating data between the primary coil and the secondary coil through the same inductive coupling.

2. The method of claim 1, wherein communicating data comprises:transmitting data from the secondary coil to the primary coil during the additional portion of the switching cycle.

3. The method of claim 2, wherein transmitting data comprises:discharging an energy storage device through the secondary coil to generate detectable pulses in the primary coil.

4. The method of claim 2, wherein transmitting data comprises:discharging a capacitor, charge pump, or rechargeable battery through the secondary coil to generate detectable pulses in the primary coil.

5. The method of claim 1, further comprising, during the additional portion, communicating data further comprises: transmitting data from the primary coil to the secondary coil during the portion or the additional portion of the switching cycle.

6. The method of claim 5, wherein transmitting data comprises: operating switches coupled to the primary coil to generate detectable data pulses in the secondary coil.

7. The method of claim 5, wherein transmitting data comprises: modifying the power transfer pulses themselves to represent data without additional modulation or encoding, such that the same pulses simultaneously accomplish both power transfer and data communication.

8. The method of claim 1, wherein the portion comprises 70% of the switching cycle, and the additional portion comprises 30% of the switching cycle.

9. The method of claim 1, wherein the portion of the switching cycle and additional portion of the switching cycle are dynamically adjustable based upon operating parameters.WLM-511208-WO-1 10Attorney Docket: WLM-511208-WO-1 10. The method of claim 1, wherein the primary coil is configured as part of a fundamental switched mode power converter topology.

11. A system comprising:a primary coil associated with a downhole tubular member;a secondary coil associated with a downhole casing string and inductively coupled to the primary coil;switching circuitry connected to the primary coil and configured to effectuate power transfer from the primary coil to the secondary coil during a portion of a switching cycle; anddata communication circuitry coupled to the secondary coil and configured to communicate data transfer from the secondary coil to the primary coil during an additional portion of the switching cycle.

12. The system of claim 11 , wherein the data communication circuitry comprises: an energy storage device; andswitching components configured to charge the energy storage device during the portion of the switching cycle and to discharge the energy storage device through the secondary coil during the additional portion of the switching cycle to generate a detectable pulse in the primary coil.

13. The system of claim 12, wherein the switching components comprise:a first semiconductor switch having a first conduction terminal coupled to the secondary coil, a second conduction terminal coupled through a first resistor to a node between a rectification diode and a load that is coupled to the secondary coil, and a control terminal; anda second semiconductor switch having a first conduction terminal coupled through a second resistor to the control terminal of the first semiconductor switch, a second conduction terminal coupled to a reference node, and a control terminal coupled to receive control signals through a third resistor.

14. The system of claim 12, wherein the switching components comprise:a PNP transistor having a collector coupled to the secondary coil, an emitter coupled through a first resistor to a node between a rectification diode and a load, and a base; andan NPN transistor having a collector coupled through a second resistor to the base of the PNP transistor, an emitter coupled to a reference node of the secondary coil, and a base coupled to receive control signals through a third resistor.

15. The system of claim 11 , wherein the switching circuitry coupled to the primary coil is configured to facilitate data communication between the primary coil and the secondary coil during the second portion of the switching cycle.WLM-511208-WO-1 11Attorney Docket: WLM-511208-WO-116. The system of claim 11 , wherein the switching circuitry comprises:a first switch coupled between a power source and a first terminal of the primary coil; and a second switch coupled between a second terminal of the primary coil and a reference voltage.

17. The system of claim 11, wherein the primary coil is configured as part of a fundamental switched mode power converter topology.

18. A wireless power and data transfer system configured for downhole deployment, comprising:a primary side circuitry including:a power source configured to provide a power signal;a primary coil coupled to receive the power signal;at least one switch operable by a primary-side controller to alternate between a power transfer phase and a data communication phase within a single switching cycle; anda secondary side circuitry including:a secondary coil inductively coupled to the primary coil;a rectification circuit configured to convert induced voltage at the secondary coil into a DC output for powering at least one downhole load; anda data communication circuit configured to induce communication pulses through the secondary coil during the data communication phase;wherein the primary and secondary coils are used for both power transfer and data communication, and wherein the primary-side controller is configured to detect the communication pulses via the primary coil.

19. The wireless power and data transfer system of claim 18, wherein the primary side circuitry further comprises a two-switch forward converter topology, and wherein the primary-side controller dynamically adjusts a ratio between a duration of the power transfer phase and a duration of the data communication phase.

20. The wireless power and data transfer system of claim 18, wherein the secondary side circuitry further comprises a rechargeable battery coupled to the rectification circuit, such that the rechargeable battery stores energy during the power transfer phase and powers downhole monitoring equipment in the wellbore environment.

21. The wireless power and data transfer system of claim 18, wherein the data communication circuit on the secondary side circuitry includes at least one transistor operated by a WLM-511208-WO-1 12Attorney Docket: WLM-511208-WO-1 secondary-side controller to discharge a capacitor through the secondary coil, thereby creating a pulse detectable by the primary side circuitry.

22. The wireless power and data transfer system of claim 18, wherein the primary side circuitry further comprises a signal detection circuit having at least one amplifier configured to produce an analog output corresponding to a voltage across the primary coil and a comparator configured to generate a digital output representing communication pulses transmitted by the secondary side circuitry.

23. The wireless power and data transfer system of claim 18, wherein the primary side circuitry is configured to implement a fundamental switched mode power converter topology.WLM-511208-WO-1 13

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