JP2019506833A - Improving wireless energy transfer using electromagnetic alignment - Google Patents

Abstract

An improved wireless energy transfer method includes directing a first energy beam having a fundamental frequency toward the energizable device. The first energy beam is formed by a plurality of polarizers of a first power access point (PAP). By combining each first polarization signal with each second polarization signal in each polarizer of the first PAP, in the energizable device, the first polarity of the first energy beam is the first Aligned with the second polarity of the second energy beam formed by the second PAP that is physically separated from the first PAP and wirelessly connected to the first PAP. Each second polarization signal is formed by rotating each first polarization signal. The second PAP receives the PAP signal via the wireless connection and generates a fundamental frequency locally from the PAP signal.
[Selection] Figure 1

Description

[Cross-reference with related applications]
This application is filed on Feb. 9, 2016, copending US Provisional Patent Application No. 62 / 292,926 entitled “PHASOR DECOMPOSITION” filed on Feb. 9, 2016. Co-pending US Provisional Patent Application No. 62 / 292,933, entitled “Switched Beam Polarization Alignment”, and “Receiver Positioning” filed on Feb. 9, 2016. US Patent Application No. 62,292,938, co-pending US Patent Application No. 62,292,938, entitled "RECEIVE LOCATION DETERMINATION", which is incorporated herein by reference in its entirety. It is done.

  The present disclosure relates generally to wireless energy transfer, and more particularly, to an efficient wireless energy transfer system and method using electromagnetic wave alignment.

  Improvements in the processing and connection capabilities of portable devices have resulted in increased energy consumption of these corresponding devices. Furthermore, there is a substantial physical limit to the amount of energy that portable devices can store, so these devices need to be charged frequently. Tethered solutions for powering portable devices include lack of connector standardization between the power cable and the device, charging cable weight and reliability, and constraints on the operating environment (eg, underwater Or critical areas), and limitations due in part to the general constraints that connected solutions impose on mobility.

  In the past, wireless charging of portable devices has been limited to short distances (eg, on the order of a few centimeters) by near-field technologies such as inductive coupling or electrostatic coupling. Far-field technologies using laser or microwave beams require power levels that are dangerously high, especially in environments involving humans. Usually, laser and microwave beams are also limited to line-of-sight applications.

  Improvements in the capabilities of portable devices have also helped enable the Internet of Things (IoT) environment where devices can be deployed on a large scale and densely to share information collectively. However, previous solutions have limited the ability of devices with significantly different power consumption requirements to efficiently power devices in an IoT environment that requires mobility. Similarly, with the increased use of radio frequency identification (RFID) tags, without undue regulatory restrictions on connections, use of dangerously high levels of power, or placement of charging stations used to charge RFID tags There is a need for an efficient way to power devices in a mobile environment.

  As will be appreciated, the embodiments disclosed herein include at least the following. In one embodiment, an improved wireless energy transfer system includes a first power access point (PAP) configured to direct a first energy beam to an energizable device. The first energy beam has a fundamental frequency and a first polarity. A second PAP having a wireless connection with the first PAP and configured to direct the second energy beam to the energizable device is physically separated from the first PAP. The second energy beam has a fundamental frequency and a second polarity. The plurality of polarizers of the first PAP are configured to form a first energy beam directed to the energizable device and to align the first polarity with the second polarity in the energizable device, the second The PAP can receive the PAP signal via a wireless connection and can also generate a fundamental frequency locally from the PAP signal.

  Another embodiment of the improved wireless energy transfer system includes one of the following features, or any combination thereof. Each of the polarizers includes a dielectric substrate interposed between the resonance plate and the ground plate, a patch antenna including a first supply point and a second supply point, and a signal connected to the first supply point. A first variable gain amplifier (VGA) configured to adjust a first amplitude of the first, and a first variable gain amplifier (VGA) configured to adjust a phase of the signal that exists between the signal and the first VGA. And a second VGA connected to the second supply point and configured to adjust the second amplitude of the signal, the patch antenna controls the polarization of the signal. The first phase shifter is configured to shift the phase of the signal over a range from minus 90 degrees to plus 90 degrees. There is a second phase shifter between the signal and the second VGA, and both the first phase shifter and the second phase shifter have a signal phase ranging from minus 90 degrees to plus 90 degrees. Combine shift. The number of the plurality of polarizers is divisible by 2, and each polarizer is connected to the antenna signal with a light cross structure. The number of polarizers is four, a first crossing device coupled to the first pair of polarizers, and a first hybrid coupler coupled to the first crossing device and the second pair of polarizers A second crossover device coupled to the first hybrid coupler pair; and a second hybrid coupler pair coupled to the second crossover device and the first hybrid coupler pair. , A switch coupled to the second pair of hybrid combiners, and a master phase shifter coupled between the antenna signal and the switch. The first polarity is one of vertical, tilt, horizontal, circle, ellipse and tilt ellipse. The first PAP is received by the received signal strength indicator from the energizable device and is used to optimize alignment of the first polarity with the second polarity. The alignment optimization uses a phasor decomposition method.

  In another embodiment, a method for improved wireless energy transfer can energize a first energy beam having a fundamental frequency formed by a plurality of polarizers of a first power access point (PAP). Guide towards the device. In each of the first PAP polarizers, by combining the respective first polarization signals with the respective second polarization signals, in the energizable device, the first polarity of the first energy beam is changed to Aligning with a second polarity of a second energy beam formed by a second PAP that is physically separated from one PAP and has a wireless connection with the first PAP. Each second polarization signal is formed by rotating each first polarization signal. The second PAP receives the PAP signal via the wireless connection and generates a fundamental frequency locally from the PAP signal.

  Another embodiment of the improved wireless energy transfer method includes one of the following features, or any combination thereof. Each of the first PAP polarizers combines the rotated first polarization signal with a respective second polarization signal having a different rotation than the rotated first polarization signal. The alignment of the first polarity with the second polarity is optimized based on a received signal strength indicator (RSSI) received by the energizable device. Alignment uses a phasor decomposition method. Both the first energy beam and the second energy beam sequentially move from one energizable device to another energizable device, and the alignment is optimized by another RSSI received by another energizable device. The alignment is optimized simultaneously for the energizable device and another energizable device by maximizing the minimum RSSI from each energizable device and another energizable device.

  In another embodiment, an improved wireless energy transfer method directs multiple energy beams to an energizable device. Each energy beam has a fundamental frequency. Each energy beam is formed by a respective power access point (PAP) having a plurality of polarizers. Each PAP is physically separated from another PAP and has a wireless connection with the other PAP. One PAP of the PAPs receives the PAP signal via the wireless connection and generates a fundamental frequency locally from the PAP signal. By combining the respective first polarization signal with the respective second polarization signal in each respective PAP polarizer, the polarities of the respective energy beams are aligned in the energizable device. Each second polarization signal is formed by rotating each first polarization signal. A planar region including a plurality of energizable devices is divided into a plurality of partial spaces. Each subspace is defined by the energy beam position from each energy beam of the plurality of energy beams. By scanning each energy beam of the energy beam along a scanning path in the subspace to detect a change in energy received in each of at least some of the plurality of energizable devices. The presence of at least some energizable devices of the plurality of energizable devices is detected. At least some energizable devices of the plurality of devices include a receiving device and one or both of a proximity device and a reference device. The reference device has a predetermined position in the planar area. A connectivity map is determined by finding the respective position of each proximity device relative to the position of the receiving device. Interpolate the physical position of the receiver and proximity device relative to the reference device.

  Another embodiment of the improved wireless energy transfer method includes one of the following features, or any combination thereof. The position of the receiving device is specified within one wavelength of each energy beam of the energy beam. Each subspace is further divided into narrower spaces by stopping one energy beam continuously and detecting the presence of the receiver by a decrease in the energy received at the receiver. Each subspace continuously stops two physically adjacent energy beams and detects the presence of the receiver between two physically adjacent energy beams by a decrease in the energy received at the receiver. It is further divided into narrow spaces. Each subspace is further divided into smaller spaces by rotating the polarity of all energy beams and detecting the presence of the receiver by a decrease in the energy received at the receiver.

  The present invention is shown by way of example and is not limited by the accompanying figures, in which like elements are indicated by the same reference symbols. Elements in the figures are shown for simplicity and clarity and are not necessarily to scale.

1 is a schematic diagram of an improved wireless energy transfer system according to an embodiment of the present disclosure. FIG. It is a functional block diagram of a control module. FIG. 5 is a graphic representation of a phase adjustment sequence for a power access point. It is a flowchart of the pseudo code for phasor decomposition. 1 is a schematic diagram of an embodiment of a controllable tilted linear polarizer. FIG. 1 is a schematic diagram of an embodiment of beam steering using a switched beam. FIG. It is a flowchart which shows the production | generation method of a connectivity map. 2 is a flowchart representation of an improved wireless energy transfer method according to an embodiment of the present disclosure. 2 is a flowchart representation of an improved wireless energy transfer method according to an embodiment of the present disclosure.

  Embodiments of the systems and methods described herein provide long-range wireless from multiple power access points (also called transmitters) (PAP) to at least one energizable device (also called application power receiver or RAP). Improve energy transfer. In one example, the energizable device is a radio frequency identification (RFID) tag. A device is considered energized when it can receive a radiated EM wave that provides the operating energy of the device from a long-range wireless energy transfer.

  In various embodiments, wireless energy transfer is achieved over long distances, at low transmission power, or both by unifying the frequency of multiple energy beams at the energy receiving point (eg, antenna) of the energizable device. Is done. The wireless energy transfer further includes at least one of phase unification and energy beam polarity unification. Various improvements in wireless energy transfer are provided by the teachings described herein, including one or any combination of the following improvements.

  In various embodiments, phasor decomposition is performed at each energizable device to improve wireless energy transfer by quickly determining the contribution amplitude, phase and polarity from each PAP. As a result, in some embodiments, the time required to unify (eg, align) at least one of the frequency, phase, and polarity of the energy beam is reduced by about 10,000, thereby reducing the iterations. Energy beam alignment can be performed in real time without need. Real-time energy beam alignment allows the RFID tag to have “instant-on” performance to maintain an optimal level of power supply during tag movement. In one embodiment, the location of each tag is tracked in real time as the tag moves.

  In other embodiments, polarization alignment is performed by switched beam selection rather than beam steering. The phased array method performs high-speed beam steering that exceeds the speed required for power transfer applications at the expense of increased cost and complexity. By using switched beam selection for power transmission, the power supplied by the PAP is increased and the multipath problem is reduced.

  In other embodiments, wireless energy transfer is improved by locating multiple sensor tags regardless of whether multipath distortion exists. A connectivity map is formed that includes the location of the RFID tag relative to an RFID reference device having a predetermined location. This connectivity map is determined by detecting the change in signal level received at each RFID tag illuminated by the scanning energy beam. Other methods are also employed to improve the resolution of the connectivity map, including selectable energy beam deactivation and energy beam polarity rotation.

  Referring to FIG. 1, a wireless energy transfer system embodiment 10 includes energy (eg, “Internet of Things” (IoT) 12 including, for example, a mobile phone 14a, a tablet 14b, a smart watch 14c, a stereo 14d, and a computer 14e. Power "). The energizable devices 14a-14e (generally 14) are merely exemplary and should not be considered as limiting the potential devices that make up the IoT 12. In one example, the devices 14 are all of the same type. In another example, device 14 is a low power device such as an RFID tag. In another example, device 14 is a high power device such as an electric wheelchair. Various embodiments replace the IoT 12 with one or more devices 14 that need not be associated with or communicate with each other.

  The IoT 12 device 14 receives energy from a plurality of PAPs 16a, 16b and 16c (generally 16). Each PAP 16a, 16b and 16c emits a respective energy beam 18a, 18b and 18c (generally 18), each energy beam having at least one EM wave. Each of the EM waves of the at least two energy beams is directed (eg, collected) to the receiving position of that device to optimize the energy received by one of the devices 14. By aligning the frequency and phase and / or polarity of each EM wave of each energy beam collected at the receiving position, a coherent energy bubble 20a is formed. Reference to aligning the frequency, phase or polarity of the energy beams in the context of the present disclosure should be understood to mean aligning (or unifying) the EM waves within and between each energy beam. is there.

  For clarity of illustration, FIG. 1 shows a coherent energy bubble 20a formed by three energy beams 18 adjacent to the IoT 12 environment. In practice, each coherent energy bubble is formed by at least two energy beams and at one point (eg, a receive antenna) of that one device to maximize the received power by one of the devices 14. Collected. In one embodiment, a plurality of coherent energy bubbles are formed and each coherent energy bubble is collected in a different device. In another embodiment, at least one coherent energy bubble is time-shared between multiple devices.

  The range 22 of the PAP 16 that transmits a sufficient energy level to the energizable device 14 is the required power that the device 14 needs to receive and the number of energy beams 18 used to form a coherent energy bubble (eg, Depends in part on the power limitation of each energy beam 18 (due to FCC limitations based on operating levels safe for life) and the absorption characteristics of the transmission medium transmitting the energy.

  In one embodiment, the energy supplied by each energy beam 18 is adjusted by communication via the communication medium 24. The communication medium 24 connects one or more devices 14 in the IoT 12 to one or more of the PAPs 16a, 16b and 16c via the path 28 and the respective paths 26a, 26b, 26c and 26d (generally 26). And the control module 30. In various embodiments, the communication medium 24 is a physical structure such as a backplane. In other embodiments, the communication medium is the same medium used by the energy beam 18. In one example, the communication medium is air (eg, a terrestrial environment). In another example, the communication medium is at least a partial vacuum as seen at orbital altitude or in outer space. In another example, the communication medium is either fresh water or salt water.

  Communication between the device 14 and the PAP 16 is used to optimize (eg, maximize) the transmission of power from the PAP 16 to the device 14. For example, each beam 18 is directed toward one or more devices so as to maximize the energy level received at each device during communication from the respective device to at least one of the PAPs 16 (eg, Induced). Similarly, the PAP 16 adjusts the phase of each energy beam 18 to maximize the received energy level at the respective device. In some embodiments, the polarity of each energy beam 18 is also aligned to maximize the received energy at the respective device. For example, communication via the medium 24 via the paths 26 and 28 is performed by one or more of the IEEE 802.3 Ethernet (registered trademark) standards, one or more of the IEEE 802.11 WiFi (registered trademark) standards. One or more of the Bluetooth (registered trademark) standards, one or more of the IEEE 802.15.4 ZigBee (registered trademark) standards, a dedicated communication protocol, any wired or wireless communication protocol Or the use of any combination of these.

  FIG. 2 is a functional block diagram of the control module 30 of FIG. The control module 30 includes a phasor decomposition module 32, a switched beam polarization alignment module 34, and a receiver position determination module 36. In one embodiment, a circuit is mounted on each module of the control module 30. Various embodiments of the control module 30 may include one of a phasor decomposition module 32, a switched beam polarization alignment module 34, and a receiver position determination module 36 to implement the respective functions described herein. Or two or more.

Phasor decomposition method (PDM)
The phasor decomposition method (PDM) described herein reduces the number of phase adjustments typified by iterative methods (eg, Gradient Ascent). Compared to the iterative method, the improvement in time required to achieve the optimal power delivered to the energizable device (eg, sensor, tag or battery) is about 10-100 sensor tags per PAP, respectively. 1,000 to 10,000 times. Ultra-high speed transmission (eg, less than 100 μs) of information including phasor contributions from each PAP received at each energizable device location controls one or more PAPs or PAPs from energized devices Sent to one of the other devices. This transmission rate is limited by the communication bandwidth between the PAP and the energizable device and the number of available communication channels (eg, in the time domain, frequency domain, or space domain). This phasor information can also be used for dynamic positioning of sensor tags or detection of people's movements that obstruct the communication path between the PAP and the energizable device. Dynamic positioning is particularly in changing environments (eg people are walking or sensors are moving), busy warehouses, industrial environments (eg including conveyor belts), coffee shops, shops, homes or offices. It is beneficial and can be used to help comply with emission standards.

  In PDM, the time required to achieve optimal power (Top) at all sensor tag positions is Topt = 4 * N * Ts + Tcomm, where N is the number of PAPs and Ts is the phase / polarization update The rate is a rate (for example, 2 μs to 50 μs), and Tcomm is a communication channel update rate (for example, 1 ms to 100 ms). In contrast, iterative methods such as steepest ascent (eg, hill-climbing) are the maximum values that yield a Topt equivalent to 20 * H * (N + 1) * (Ts + Tcom) to 100 * H * (N + 1) · (Ts + Tcom) Requires multiple iterations, where H is the number of sensors per TX, and the factors 20 and 100 are the number of iterations required to reach the optimal value. There is also no guarantee that the optimum power required by the steepest ascent method is not local optimum.

  The PDM reduces the amplitude, phase, and polarization vector phase of the EM wave transmitted from each contributing PAP for each energizable device, with no iterative delay (limited by the number of simultaneous communication channels). How to get. The radio frequency (RF) power signal at each sensor tag location combines multiple lines of sight, reflections and diffractions from multiple PAP sources in addition to noise.

  In the description of PDM, the following general assumptions and terminology are used. A power access point (PAP) is present at the radiating position of the RF energy. An energizable device is a device that receives radiated RF energy (eg, an RFID sensor tag). The energizable device is also called an applied power receiver (RAP). The PDM calculation assumes that the relative phase accuracy of each PAP (eg, due to drift) is small (eg, <30 °) during the phase adjustment period, which is actually between 1 ms and 100 ms, but can be as short as a few microseconds or as long as a few seconds depending on the type of synchronization used and the resulting phase accuracy.

  The term “phase” means 2D phasor or “phasor” phase. The term “phasor” means a two-dimensional (2D) phasor represented by a pair of complex or vector coordinates in a polar coordinate system as used throughout this disclosure. In general, a phasor can be expressed in any other coordinate system. The term “3D phasor” means a three-dimensional (3D) vector formed by adding two 2D phasors of each orthogonal EM wave polarization. In general, since EM polarization is a “polarization vector”, EM waves are two constituent orthogonal polarizations (eg, vertical / vertical), each having independent 2D phasors (eg, amplitude and phase). Horizontal). The amplitude in this case is the amplitude of the polarization vector (for example, the same amplitude as that of the component 2D phasor), and the phase of the polarization vector is in the (special) third dimension of the 3D phasor “polarization angle”. There is (for example, a polarization angle of 90 degrees corresponds to circular polarization).

  The RSSI reading is an average power reading averaged over at least several cycles of a fundamental (center or carrier) frequency such as 915 MHz. Assuming that the propagation channel from any PAP to any energizable device can be modeled as a complex constant due to the narrow bandwidth occupied during phase adjustment, and as a result at the energizable device location When the phasor is multiplied by the complex constant of each PAP, the product of the channel constant per PAP and the phasor of the PAP is summed.

  In terms of fading mitigation, if significant fading is expected, the phase shift update rate can be reduced to reduce the occupied frequency bandwidth to a point where the fading loss is below the threshold. In addition to increasing the phase adjustment period, the center frequency can also be adjusted. Either of these two methods can be performed using feedback from the energizable device. For example, if the energizable device is located where the waveform from one or more PAPs is destructively increasing (independent of the 3D phasor), the energizable device will initiate a response or reported The center frequency can be adjusted until the RSSI is improved.

  Unlike the hill-climbing method, the PDM performs 90 ° and 180 ° phase adjustments from some initial phase (θ0), except for the last one, on the contributing phasor. The 90 ° / 180 ° phase shift mainly facilitates the calculation and reduces the independence of the equations (eg, orthogonality) due to quantization and other noise that would have become stronger with small angular changes. That's what you choose to enhance.

  In PDM, a phasor sum can be expressed using one phasor and the sum of the remaining phasors. The phase of this one phasor is adjusted 90 °, 180 ° to form three equations (0 °, + 90 °, + 180 °) and three unknowns, from which the phase and amplitude of this one phasor are calculated. The resolved phase is the phase between a single phasor and the sum of the remaining phasors, not the cumulative phasor (which is a constant). Therefore, a further calculation step is performed to convert this into a phase related to the phasor accumulation. This procedure is repeated N-1 times to obtain the amplitude and phase of all individual phasor components (the last phasor is self-evident because the sum is known and the remaining phasors are also known). The resulting combination of phasor and amplitude and phase can be optimized “one shot” by adjusting all phases to the optimal configuration simultaneously. This procedure has the further advantage of acquiring all phases and amplitudes at all sensor positions at once (considering time-division multiplexing of the communication channel as long as sufficient power is received).

  The PDM sequentially adjusts the phase of signals coming from each PAP at specific time intervals. For each PAP, the phase is 0 °, + 90 °, + 180 ° in each of the two polarization directions, or any other six angles that are sufficiently different (other angles that can be resolved into 0 °, 90 ° angles). Adjust (for example, a total of 6 phase / polarization values) and keep the phase / polarization of the remaining PAP at a constant (predetermined) polarization of 0 °. This procedure is repeated for each PAP in the cluster (or subset). In some embodiments, each PAP is assigned a time slot of phase change based on proximity to each other and proximity to energized devices to improve near-optimal phasor coupling time intervals.

  When the energizable device detects a particular RSSI leap, it records the resulting RSSI reading at each energizable device corresponding to the phase / polarization change at each PAP. Send a vector of RSSI readings corresponding to the phase change of 0 °, + 90 °, + 180 ° in each of the two polarizations of all of this PAP to the PAP (s) and correlate the RSSI change to the phase change. . In another embodiment, RSSI measurement based on synchronization between PAPs by synchronization with the master or by predicting the phase adjustment time of the PAP based on other information (eg, communication from the PAP, spurious emission during phase jump) To start.

  After the PAP receives RSSI vectors from all sensors, it solves the equations necessary to obtain a phasor for each contributing PAP (including itself and other neighboring PAPs). The sensor tag determines the time slot boundaries (eg, by observing RSSI changes or SYNC signals) and / or solves the equations, returns the answer, and transmits the payload (faster, with less energy consumption) Or wait for a sync packet from the master PAP to measure the exact moment when the phase is expected to change.

  FIG. 3 illustrates an example embodiment of a PDM that adjusts the phases of three PAPs, including signal transmissions between a master PAP, a slave 1 PAP, a slave 2 PAP, and a plurality of energizable devices (eg, sensor tags). . Specifically, a flow event including synchronization (Sync), RSSI reading, and phase adjustment is shown. A total of 6 PAP phase adjustments including 0 degrees, 90 degrees, and 180 degrees (for example, a total of 6 adjustments) are performed for every two polarizations.

  In various embodiments, the PDM of FIG. 3 is performed twice for every two phasor polarizations. In the embodiment, only one PDM cycle is performed when polarization alignment is not required. In the PDM cycle, for each polarization, the master PAP transmits a synchronization (Sync) pulse 50, and the first energizable device (slave 1) and the second energizable device (slave 2) are synchronized pulses 52 and 54, respectively. Start by receiving as. Select polarity for transmission from master, slave 1 and slave 2. In 56, 58 and 60, the master PAP sequentially adjusts the phasors of the master, slave 1 and slave 2 based on the phasor decomposition calculation of the previous PDM cycle. At 62, 64, and 66, the master PAP transmits a phasor with phase adjustments of 0 degrees, 90 degrees, and 180 degrees, respectively, whereas the phase adjustments of slave 1 PAP and slave 2 PAP remain at 0 degrees. In each energizable device, the RSSI level of each of the three phases transmitted by the master PAP is measured. At 68, the next phasor decomposition calculation is performed on the measured RSSI values from each energizable device corresponding to each phase of the time slots 62, 64 and 66 of each PAP (eg, master, slave 1 and slave 2). Transmit to the device. In one embodiment, the device that receives multiple RSSI values is the master PAP.

  At 72, 74, and 76, slave 1 PAP transmits phasors with phase adjustments of 0 degrees, 90 degrees, and 180 degrees, respectively, whereas the phase adjustments of master PAP and slave 2 PAP remain at 0 degrees. In each energizable device, the RSSI level of each of the three phases transmitted by the slave 1PAP is measured. At 78, the next phasor decomposition calculation is performed on the measured RSSI values from each energizable device corresponding to each phase of time slots 72, 74, and 76 of each PAP (eg, master, slave 1 and slave 2). Transmit to the device. In one embodiment, the device that receives multiple RSSI values is the master PAP.

  In 82, 84, and 86, slave 2 PAP transmits phasors with phase adjustments of 0 degrees, 90 degrees, and 180 degrees respectively, whereas the phase adjustment of master PAP and slave 1 PAP remains at 0 degrees. . In each energizable device, the RSSI level of each of the three phases transmitted by the slave 2PAP is measured. At 88, the next phasor decomposition calculation is performed on the measured RSSI values from each energizable device corresponding to each phase of each time slot 82, 84, and 86 of each PAP (eg, master, slave 1 and slave 2). Transmit to the device. In one embodiment, the device that receives multiple RSSI values is the master PAP. Thereafter, in embodiments where polarization alignment is required, this PDM cycle is repeated for the second polarization.

FIG. 4 is a flowchart representation of pseudo code for phasor decomposition. The polarization alignment calculation starts with the following three expressions representing phasors with zero phase adjustment, 90 degree adjustment and 180 degree adjustment respectively.
S ² _1N0 = A ² ₁ + S ² _2N + 2 * A ₁ * S _2N cos (θ ₀ ) [1]
S ² _1N90 = A ² ₁ + S ² _2N + 2 * A ₁ * S _2N cos (θ ₀ + 90 °) [2]
S ² _1N180 = A ² ₁ + S ² _2N + 2 * A ₁ * S _2N cos (θ ₀ + 180 °) [3]

By rearranging the equations [1], [2] and [3], the following equations [4] and [5] are derived from the phase angle θ0, and the amplitude A1 is obtained.
tan (θ ₀ ) = 2 * [ΔS ² ₉₀ / ΔS ² ₁₈₀ ] −1 [4]
β ₀ = [sin (θ ₀ ) * A ₁ / S _1N ] [5]

In the formulas [1], [2], [3], [4] and [5], S _2N represents the sum of all phasors except phasor 1, and S _1N0 , S _1N90 and S _1N180 are phasor 1 Represents the total number of phasors when phasor 1 is rotated 90 degrees, and when phasor 1 is rotated 180 degrees, and θ is between phasor 1 and S _2N Β ₀ represents the phase angle between phasor 1 and the total of phasor S _1N . After obtaining the phase angle and amplitude using equations [4] and [5], the procedure is repeated for another phasor excluding the last phasor that can be calculated from the previous phasor. In total, 1 + 2 * (N-1) RSSI measurements and phase adjustments are performed.

PAP Synchronization and Master Selection Method In one embodiment, a single master PAP is selected. In another embodiment, there is no master PAP, and coordination between PAPs is performed to perform frequency tuning.

  In one embodiment of communication channel based synchronization using SYNC, timestamp messages, all PAP sync messages with a low error probability (eg, highest communication channel signal-to-noise ratio (SNR) or lowest interference). The master that can communicate is the best master. In one embodiment in which a separate RF frequency is used to synchronize the PAP, the highest SNR at the synchronized RF frequency is required.

  Example embodiments for performing synchronization between PAPs include one or more of the following. The wireless embodiment uses an optical (eg, infrared) communication channel between the PAP and the energizable device that transmits a pulse or modulated signal from the master using one of the fluorescent (passive) 100/120 Hz harmonics. Including. The wireless embodiment includes an acoustic communication channel between the PAP and the energizable device, where the master transmits a tone or modulated signal, or uses an external source of known signal (eg, 120 Hz hamming). The wireless embodiment includes a radio frequency (RF) communication channel between the PAP and the energizable device, where the master PAP transmits a continuous wave (CW) wave or modulated signal and other PAPs synchronize to it.

  One embodiment includes a distributed system in which all PAPs exchange timing packets or (CW bursts) with all other PAPs to adjust their clocks to an average that eventually converges. Master PAP can be 100/120 Hz or fluorescent light harmonics or converter, Wi-Fi (timing) signal from router (s), cell phone signal, or timing signal from cell phone tower, or GPS / Gronus ( Use an external source of known signals, including no master, but each PAP has an external antenna).

  In one embodiment of the PDM system, radiation emission including an external source (eg, smoke detector) or an open loop isotope timing device (eg, cesium atomic clock) is used synchronously. In one embodiment of the wired system, an existing AC power line is used for synchronization by locking to 50/60 Hz or its harmonics. In another embodiment, the master sends a synchronization packet over the power line. In another embodiment having a distributed system of PAPs, all PAPs exchange timing packets (eg, over power lines or using load-modulated Ethernet). In another embodiment of the wired system, one or more PAPs use USB, RS232, or Ethernet. In another embodiment of the wired system, one or more PAPs use a dedicated coaxial or similar single wire that contains a single tone signal or modulation signal. In another embodiment of the wired system, one or more PAPs use guided wave propagation (eg, surface waves in a dry wall or air duct).

Synchronization of PAP with master This deployment is assumed to be known (eg, IP network topology, PAP clustering), and the master is assigned manually or algorithmically. For Wi-Fi and similar protocols, there is a network discovery operation phase (eg, once at startup and once every X seconds) that connects the PAP MAC and / or IP address within the cluster. In various embodiments, each PAP is programmed with a known list of possible MAC addresses for a particular deployment. In other embodiments, there is also Telnet / SSH to routers that properly consider security issues and obtain an ARP table to look for a MAC address range corresponding to the PAP. PAPs communicate with each other (in one example every Y seconds) after a list of connected PAP MACs and / or IP addresses is known.

  Information exchanged includes, for example, Wi-Fi based coarse SYNC, PAP_MASTER_RSSI table, RAP_table (short / long version), synchronization message, user message (between user and RAP sensor), status and configuration There are different types of.

  If a master is not manually selected during startup, or when a new PAP is discovered on the PAP cluster network, the master selection algorithm is initialized (optionally holding off other tasks). In one example technique for master selection, all PAPs in the cluster attempt to become masters one at a time (eg, using MAC address sorting or IP address sorting). For each candidate PAP, the candidate communication (eg, comm) channel is set to TX and the other PAP is set to RX. Candidates broadcast every message (ideally a synchronization message to reduce synchronization time) over a common channel, and all non-candidate PAPs are sufficient (within router latency variation such as 1 second) Measure the RSSI of this message (at a predetermined interval starting with a good Wi-Fi based coarse synchronization). Each PAP in the cluster writes (candidate ID, RSSI from the candidate) to the PAP_MASTER_RSSI table for each candidate. At the end of master selection, each PAP has a table of RSSIs for each master candidate. PAP exchanges these tables via a Wi-Fi network or other communication channel. Since each PAP has the same set of tables, a (same) decision is made as to which PAP should be the master. Maximizing the minimum RSSI in the PAP_MASTER_RSSI table is one such option, since the master with the lowest probability of bringing an error SYNC message to all other PAPs in the cluster is assumed to be the best master. Maximizing a weighted target function such as Score = TotalRSSI * W1 + minRSSI * W2 if> threshold, and Score = minRSSI * W3 if minRSSI <threshold may be another option. At this point, clustering is also arbitrarily performed, and a master per cluster is selected based on the communication channel connectivity graph and the minRSSI value, and the master is added until the minRSSI exceeds the threshold value. For example, if you have a warehouse with 20 PAPs and one master in the center, this master may cover 15 of the PAPs, but the end PAPs may not receive a sync signal . To remedy this, try to optimize minRSSI again by increasing the number of masters until minRSSI exceeds the threshold.

All the side-by-side PAP_MASTER_RSSI tables for selecting one master (only the triangular portion of the table without diagonal lines is unique)

  After the master is selected for the first time, this master sends a synchronization signal and the other PAPs synchronize their clocks. The master sends a continuous synchronization message at a predetermined exact interval, such as 1 to 5 seconds (1 ppb / s XTAL) derived from the master's highly stable oven controlled crystal oscillator (OCXO) (eg, one prototype) <1 ppb / sec & 10 ppb / day drift OCXO is used). Other PAP nodes calculate the time difference that should be the synchronization interval time for their own OCXO and compare this time difference (highly deterministic chain, high priority interrupt for synchronization packet RX, OCXO clock MCU based counter). After calculating the time difference, the PAP calculates the OCXO's relative frequency shift relative to the master (according to the lookup table) and adjusts the OCXO tuning + feedback + drift estimate. The PDM algorithm per PAP is so fast (eg, 10 μs to 1 ms) that the phase from 10 μs to 1 ms does not change significantly even if OCXO drift is present. For example, for unadjusted <1 ppb / s drift, the phase change is about <3 deg at 8 * 1 ms (8 PAP). However, during a period of 10 ms to 1 s where there is no phase transition (phase for optimal power supply), the phase is shifted by an amount depending on the synchronization interval and the optimal power interval. This amount can be reduced by adaptively changing the synchronization and the optimal power interval (for example, a synchronization period Ts of 1 second, an optimal power period Topt of 100 ms results in a maximum error of <18 deg and above average. Is much lower).

Synchronizing PAPs without using a master In one example technique similar to the master selection procedure, each PAP attempts to become the master, but each PAP, but not all PAPs in the cluster as described above, Based on this, the PAP_MASTER_RSSI table is written. In this case, unlike the method with one master per cluster, the master trial procedure is performed every 100 ms 2s (not just at startup or when adding a new PAP). Along with the master candidate ID and the RSSI from the candidate, an OCXO (quartz crystal oscillator) frequency difference is calculated for each candidate. Calculate and apply the average of the OCXO frequency differences. This is repeated for each PAP. All OCXOs reach the same frequency at the world average over time. For example, if one PAP is added later between two separate PAP clusters, the average of each cluster is stable independently, but if PAP is added to the center, the initial value of the center PAP Is set to the average of the two clusters, applying a slight pressure to both clusters and slowly moving the average toward the central PAP will eventually equalize the system. This procedure is slower than the procedure with a single master, but significantly speeds up to avoid communication channel-based clustering when PAP forms a deterministic low drift mesh network. The total average can be synchronized at N synchronization intervals where N is the mesh network depth or the maximum number of hops. In a mesh network, the time to reach synchronization is N times longer, and if not using a mesh network, it is probably several hundred times longer (due to a “moving” average) than one master method per cluster.

Synchronization of Energizable Device with PAP Master In one embodiment, it listens to the same SYNC signal as the SYNC (synchronization) signal sent from the master PAP to the slave PAP (as done in the current prototype). In another embodiment, multiple RSSI readings are performed to detect RSSI changes that correlate to the phase / polarization changes made by the PAP.

Implementation of PDM Prototype PAP synchronization is performed via a communication channel over which energized devices can listen. When the energizable device has enough energy to listen for the duration of the PAP synchronization cycle, it changes the communication channel frequency to the PAP synchronization channel and waits for synchronization. The energizable device goes to sleep after receiving synchronization (with the timer turned on) and has enough energy to transmit the RSSI vector (+ ADC reading), and the expected phase change If it does not have enough energy, it sleeps longer (+ Tsync err). If a voltage drop occurs, this procedure is repeated when there is enough energy again. The initial charging is done in a random phase, so it takes (statistically) some time to accumulate enough energy for the first synchronization RX and the first RSSI TX.

  If the energizable device cannot receive synchronization but is storing enough energy, it will look for changes in RSSI and its variance over time (assuming that the optimal power duration is constant). And) determine where the phase adjustment window is statistically __. During the optimal power interval, the phase changes (although slowly) and is proportional to the reference drift + multi-RAP optimal power delivery phase adjustment, so the phase jumps quickly. Thus, the optimum combination of the energizable devices is not changed. In order to detect the RSSI change during the phase change, the energizable device needs to perform sampling using an ADC that is faster than the phase change. Thus, for example, when using a 10 μs phase change in PAP, the RAP ADC is> 300 KHz, but the phase change interval = N * 5 * 10 μs + only needs to be sampled during dispersion, where N = PAP It is a number and distribution is an error due to asynchrony.

  If the energizable device receives slightly lower energy due to the random phase and charges at some point but is below the harvester threshold for a long time, there is no possibility that the energizable device will respond by discharging the capacitor . In this case, this solution does not improve the range, but this is a statistically very rare case.

Comparison with iterative algorithm The iterative algorithm reads RSSI values multiple times during optimization. Common types of algorithms include steepest ascent (hill climbing), genetic algorithms, min / max, LMS, and variations / combinations with randomization to avoid local optimization.

  Disadvantages of the iterative method include multiple communication processes to achieve optimization. Since RSSI needs to be measured at multiple points in time, stable communication between RX and TX is required. Disadvantages of gradient-based methods include noise amplification (eg, less robust in realistic scenarios). Basically, the gradient calculation is a derivative calculation, where the dependent variable changes slightly when the independent variable changes slightly (eg, a slight phase change greater than a slight RSSI change). The disadvantage of random and genetic algorithm-based methods is that the noise is initially not amplified and is close to optimal. Although convergence takes time, convergence occurs at the absolute optimum point, but is about 10 to 100 times lower than when using the hill-climbing method.

  An advantage of the iterative method is that it does not inhibit RSSI away from the optimum after the optimum condition is achieved. The iterative method also uses a simple calculation that calculates the RSSI difference and adjusts the phase by multiplying a constant (eg, gain constant) by a derivative (eg, partial derivative for a particular TX). . The iterative method is slightly more complex than the genetic algorithm.

  The phasor decomposition (PDM) embodiment finds all component signal amplitudes and phases in the energizable device. The total amplitude is measured 2 * (N−1) times (˜2 * (N−1) * 50 μs + Tcom) by adjusting the individual phasor phases all 90 ° and 180 ° in order, where N is the corresponding phasor Is the number of PDM simultaneously finds all phase and amplitude values at all energizable device locations (limited by the communication channel), thus optimizing the power at all locations simultaneously given the power allocation priority. . Compared to the hill-climbing method, the speed improvement of PDM is about 20 * N-100 * N, where N is the number of PAPs (and the coefficient 20-100 depends on the number of steps of the hill-climbing algorithm).

  Consider an example of N PAPs having the same frequency and adjustable phase. At the receiver, these amplitudes and phases change arbitrarily due to multipath propagation. In the present disclosure, the phase and amplitude are not time varying (eg, measurements are made much faster than amplitude / phase changes). In order to align the phases of the incoming waves at the receiver, various methods can be employed depending on the trade-off of response speed, electromagnetic wave resistance to change / noise. The phase can be adjusted incrementally and gradually trying to reach some optimal point (usually a local maximum). This adjustment can be made using various algorithms such as steepest climb / hill climbing or genetic algorithms, or using PDM to estimate the current phase / phases state of individual phasors. Thus, the maximum value can be reached in one step after having the phase / phase. The hill-climbing method requires stable communication between RX and TX for each “step climbed” due to its feedback property. In PDM, “1” is obtained by correlating the phase change and the RSSI change. This is not the case because the optimal value can be provided in "times", thus saving the power used for communication.

  The effectiveness of wireless RF power transfer is limited by increasing the operating frequency as well as increasing the physical separation distance between the PAP and the energizable device (eg, user equipment, receiver or tag). These limitations are overcome by using multiple PAPs. When a plurality of PAPs are developed at random, there are a plurality of incoming waves in which unknown discrete phases all interfere constructively or destructively, so that optimum reception cannot be performed at the position of the energizable device.

  Further inefficiencies are not the same for the polarizations directed from each individual PAP to the energizable device and at the location of the energizable device, specifically at the receiving location (eg, due to reflection from the transmission medium). This is due to the weighted wave from the polarization of each PAP. In each energizable device, the polarization is unknown and disjoint, and the effect of having an arbitrary position for each PAP having its own reflection and other conditions further improves the alignment of the polarities reaching the device from multiple PAPs. Make it complicated.

  Even if the PAP can transmit linearly polarized waves, the polarization received at the energizable device can be any combination of orthogonal polarizations due to the multipath effect. The resulting polarization can be rotational linear polarization (as described above), right or left circular polarization, or tilted elliptical polarization.

  In various embodiments, a similar algorithm used for phase alignment is used to ensure that the resulting weighted wave at the receiving device has the same polarity as the component wave from each PAP. In one example, the polarity is vertical. In other examples, the polarity is one of vertical, slope, horizontal, circle, ellipse or slope ellipse. For clarity of explanation, in the following example embodiments, the alignment polarity is vertical. It should be understood that other polarities may be realized in other embodiments without departing from the scope and spirit of the present disclosure.

  A switched beam is used to guide the transmission beam from each PAP. A switched beam structure is used that requires only a Butler matrix that incorporates a crossing structure and a single pole multiple throw (SPMT) switch. In some embodiments, the intersection structure is a “wight intersection” structure. FIG. 6 shows an example embodiment of this structure for a four element array. In other embodiments, a different number of elements (eg, 8 or 16 elements) are used. Each of the four outputs from the SPMT switch provides a different phase shift set for the four signals reaching the four patch antennas. These different sets of phase shifts cause the composite beam to form its maximum in different directions or spatial angles (similar to a phase array). This corporate feed results in M power boosts of the energizable device, where M is the number of elements compared to a single antenna element.

  Only energizable receivers at the intersection of multiple beams from multiple transmitters are illuminated or energized. Within this intersection space, the multiple beams have different polarizations at different locations of the multiple receivers due to multipath propagation. The correct choice of multiple transmitter polarizations is either: a) each receiver sequentially receiving all transmitted signals with the same polarization, or b) the maximum “minimum” achievable at one of the receivers. So that all receivers receive all transmitted signals having "received power" simultaneously. This maximum minimum received power occurs at any one of the receivers, and the other receivers receive more power than the minimum received power. In various embodiments, the polarizations at multiple transmitters are iteratively adjusted according to a method (eg, hill climbing or PDM) until the maximum minimum received power at one of the receivers is achieved.

  According to various embodiments, multiple PAPs are used to compensate for the energy loss of the RF energy beam received at the receiving device due to an increased separation distance between the PAP and the energizable device. A phase-locking technique that ensures that the energy beam by each PAP described herein received at the energizable device reaches all incoming signals in energized device in phase regardless of the position of each individual PAP. All phases unified by.

  According to various embodiments, the received phase and frequency of each PAP used to transmit power to one or more energizable devices simultaneously is constant and the respective phase and frequency of all other PAPs. Is the same. In one embodiment, the same constant phase and frequency described above is achieved by phase locking all PAPs within the range of the master PAP to a single predetermined master clock frequency.

  Each phase and frequency of the PAP is monitored and adjusted in real time as it is continuously locked. However, the PAPs are not all at the same physical location, and the path between each PAP and the receiving device is not the same, so the incoming polarization received from multiple PAPs at the energizable device location is the same. It is not a thing. Each PAP has its own reflection source and other operating conditions for other PAPs.

  Since PAPs are not physically aligned in space, each incoming EM wave of energy beams from multiple PAPs (also referred to herein as “transmitters” or “Tx”) is (herein (Also referred to as “Rx”) at the position of the energizable device, each can have a different polarization. In the worst case example, the polarization of each EM wave at the position of Rx is orthogonal to another EM wave (eg, vertical and horizontal, or right and left circles). In this case, the total received power in the receiving apparatus decreases due to polarization misalignment.

  In many embodiments, multiple PAPs and receivers are nominally all within a horizontal plane (eg, the same floor of a building) and the resulting propagation direction of all transmitted EM waves (eg, a pointing vector). Exists almost in the horizontal plane and can align all the polarizations of the incoming waves.

  In one embodiment, with each improvement in power received at the receiver generated by the polarization rotation of the linear polarization from each Tx, all incoming waves at the location of Rx are vertically co-polarized, This increases the power of Rx by a multiple of N, which is the number of PAPs.

Using the technique for performing polarization alignment as described above, the power received at the receiver is improved by N * N * N = N ³ times compared to using a single PAP. This improvement is due to three factors: a) use of multiple PAPs, b) phase alignment of EM waves at the receiver, and c) polarization alignment of EM waves at the receiver. By comparison, an arbitrarily deployed PAP without phase and polarization alignment can only provide an N-fold improvement over the use of a single PAP.

  The polarization rotation used here is performed by using polarization technology for the antenna in PAP. In the first example, as shown in FIG. 5, double orthogonally polarized waves each having a specific amplitude normalized to −1 to 1 are simultaneously transmitted from each PAP. Each maximum polarization rotation required for each PAP to achieve vertical polarization addition at the receiver is ± 90 degrees.

  Referring to FIG. 5, in embodiment 130 a first variable gain amplifier (VGA) 134 is used to amplify a single feed 140 and combine in patch 132 with a second feed of the same signal. A second VGA 136 is used to amplify the second feed and a phase shifter 138 is used to phase shift from zero degrees to 360 degrees. In one embodiment, the phase shifter of the second feed shifts the phase of the signal by nominally plus or minus 90 degrees. In another embodiment, both the first feed and the second feed are phase shifted to produce a zero to 360 degree differential phase shift between the first feed and the second feed.

  In addition, in one embodiment with three or more PAPs, it is necessary to verticalize the individual received polarizations at the receiver location to allow complete polarization alignment. Alternatively, another polarization that is the same for each EM wave reaching the receiving device from each PAP is used.

  In the above-described PAP that transmits all linearly polarized waves, the polarization received in the energizable device is a combination of orthogonal polarizations due to multipath. As a result, the polarization in the energizable device becomes a rotational linear polarization, a plurality of right or left polarizations, or inclined elliptical polarizations.

  According to some embodiments, multiple PAPs individually adjust each polarization of the EM wave received by the energizable device such that a vertical wave is formed at the receiving device.

  Each of the plurality of PAPs simultaneously transmits double orthogonal polarizations each having a specific complex (amplitude and phase) normalized to 0 to 1. As shown in FIG. 5, each transmitter has two amplifiers with variable gain (VGA), at least one of which includes a phase shift capability of zero to 360 degrees.

  In some examples, multiple PAPs use a predetermined threshold to determine whether polarization alignment is required. Further, in various embodiments, the polarization alignment procedure uses received strength signal indicator (RSSI) measurements from each energizable device. In other embodiments, other methods of measuring the power received at the energizable device are used.

  The RSSI measurements from each energizable device are returned to the currently aligned PAP, and in one example, the hill-climbing algorithm is used to guide the polarization of each access point to its final state. In another embodiment, the PDM method is used to guide polarization alignment to its final state.

  In some embodiments, each PAP uses switched beam beam steering rather than phased array beam steering. The phased array method performs extremely fast beam steering that is not necessary for power applications. In addition, the phased array system also requires at least one phase shifter per antenna element, which increases system complexity and cost. The switched beam steering structure 150 shown in FIG. 6 has one Butler matrix 160 and one unipolar (utilizing four hybrid couplers 162, 164, 168 and 170 and two Wight crossing structures 166 and 172). Only the multi-throw switch 174 is required. The switched beam steering structure embodiment 150 includes four examples of controllable tilted linear polarizers 152, 154, 156 and 158.

  The switched beam beam steering system includes a master phase shifter 176 that performs phase alignment between the plurality of PAPs described above. As a result, M power boosts are achieved by using the switched beam antenna array method. M here represents the number of antenna elements compared to a single element and is a further factor added to the N * N * N times increase mentioned above.

  In applications involving many receivers, such as warehouses, where the energizable device is a radio frequency identification (RFID) tag, determining the location of each tag is important. It is desirable not only to have the RFID tag energized and read, but also to identify which shelf the tag is located on. The warehouse is large and includes many fixed metal objects (eg, shelves) and dynamic metal objects (eg, forklifts) so that direction finding (DF), angle of arrival (AOA), time difference of arrival (TDOA) and Standard positioning techniques based on relative received power levels are useless. Therefore, there is a need for a location determination technique that works in a high multipath environment.

  In various embodiments, a power transfer system supplies power to a receiving device, such as an RFID tag, from a group of PAPs each coherently locked to a common frequency. By adjusting the relative phase of the signal transmitted from each PAP, an energy “bubble” is formed in the three-dimensional space, and power is supplied to all energizable devices in each “bubble”. As the energy “bubble” passes through a three-dimensional (3D) space by changing the relative phase of the power access point, a different series of energizable devices are energized. Note that due to the multipath environment present in the 3D space (eg, warehouse), the actual “bubble” position may not be speculatively clearly identifiable.

  Therefore, it is desirable to identify the location of energy “bubbles” for each set of relative phases at the power access point and reduce the number of “bubbles” simultaneously formed in 3D space to one.

  Note that the energy “bubble” is formed by the phase alignment of the transmission signals from each PAP, so its size is nominally related to the wavelength of the transmission signal, which is a half wavelength in each direction. In the case of a 915 MHz transmission signal, the bubble size is approximately 16 cm × 16 cm × 16 cm.

In an embodiment that includes a location warehouse, each energy “bubble” illuminates a group of energizable devices (eg, RFID tags) where each device is proximate to another device. Once the energizable device reports its identity (and data), these identities can be grouped. As the energy “bubble” moves to an adjacent uncertain location, the energizable device continues to report back (by continuing to be energized by the energy “bubble” at that new location) (eg, no longer “ Something will not exist (by not being energized by the “bubble”). After scanning the three-dimensional space with “bubbles”, a connectivity map can be created that indicates the closest device of each energizable device.

  This connectivity map does not provide the physical location of each device. However, multiple “reference” energizable devices (eg, RFID tags) can be placed at known locations throughout the three-dimensional space. Thus, the energizable devices are arranged as the closest devices to the reference tag and are arranged by determining the position of all energizable devices using interpolation between groups associated with different reference tags based on the connectivity map. be able to. In some embodiments, such as determining the proximity of the receiving device to the PAP, each position of the PAP is also used as a reference position. Overall, the position of the reference energizable device and the position of the PAP are all reference positions.

  In various embodiments, there are multiple energy “bubbles” for each set of PAP relative phase settings, and the connectivity map creates multiple ambiguous positions for the position of the energizable device. As the number of PAPs used to form energy “bubbles” increases, it is advantageous that the number of energy “bubbles” formed simultaneously decreases.

First position ambiguity resolution The difficulty of position ambiguity can be eliminated by forming a single energy “bubble” rather than a plurality of inherent “bubbles”. The method of forming a single energy bubble in a high multipath environment is based on a real time delay. Here, instead of a constant relative phase shift, coherent transmission from all PAPs is frequency ramped simultaneously in a frequency modulated continuous wave (FM-CW) method or pseudo-noise (PN) frequency hopping (FH) method. Alternatively, all power access points are phase modulated simultaneously or phase (DS) spread directly. Similar to the relative phase shift of unmodulated PAPs, the modulation time delays at each PAP combine coherently to form an energy “bubble” only at locations where the real time delays are exactly the same. This greatly reduces the number of energy “bubbles” formed in the three-dimensional space, thus reducing (or eliminating) the ambiguity of the connectivity map.

  The location of the separated energy “bubbles” is controlled by the relative start times of the FM-CW lamps (or PN codes for FH and DS spreading) at each PAP. As this relative start time changes, the position of the separated energy “bubble” moves in the three-dimensional space. For each series of relative start times in the PAP, the actual location of the separated energy “bubble” is determined from the response of the “reference” location. The difficulty with using these disambiguation techniques is that the required bandwidth (FM-CW ramp rate, FM hop rate) increases with the required spatial resolution. This wide bandwidth is unacceptable in most RFID tag location situations.

Second location ambiguity resolution Another way to resolve the location ambiguity of energy “bubbles” is to separate the simultaneously formed “bubbles” into different distinct groups at the same time as the connectivity map is created. is there. This separation operation works in conjunction with the “adjacent” group connectivity operation to resolve most if not all ambiguities. A three-dimensional map of the positions of all energizable devices in a three-dimensional space (e.g., a warehouse) is generated along with a known location of the reference energizable device (or reference location in some embodiments).

First, energy “bubbles” are separated into subspaces by beam switching using the switched beam capability of PAP. With each PAP having N selectable beams in the horizontal (orientation) plane, the (warehouse) space can be easily subdivided into N ² subspaces. The power of 2 in this case reflects the number of spatial dimensions to cover, not the number of PAPs used. Further, when the vertical (rising) coordinate is divided into M beams, the space can be subdivided into M × N ² partial spaces. For multiple PAPs that contribute to the formation of energy “bubbles” in a subspace, the probability of having multiple ambiguous energy “bubbles” is greatly reduced.

In a wide space (for example, a warehouse), the entire space can be divided into different regions, and each region can be subdivided into N ² partial spaces. This not only limits the range from the power access point to the receiving device, but also speeds up operation through parallel processing.

  Further improvements can be made to the spatial separation into different subspaces. For energy “bubbles” that are substantially equidistant from all PAPs, the amplitude of the signal from each PAP is approximately the same. However, an energy “bubble” close to a single PAP does not necessarily do so because it receives most of the energy from that PAP. As a result, each PAP is turned off in turn and the energized devices (eg, RFID tags) are observed to “blink” the response to separate multiple simultaneous energy “bubbles” into different groups can do. As used herein, the term “flashing” means returning to the on state when stopped and the PAP is turned back on. Alternatively or in addition, if the receiving device can return the received signal strength indication (RSSI), “flashing” is considered a substantial RSSI change. A receiver that “blinks” is close to a PAP that has been turned off, and a receiver that does not “blink” is not nearby. This procedure groups multiple ambiguous energy “bubbles” into a subspace of p + 1 (P is the number of power access points) in the warehouse space, greatly reducing location ambiguity.

  In one embodiment, an improved version of this technique includes turning off two adjacent PAPs simultaneously. In this case, the energizable devices located between these PAPs “blink”, while the energizable devices far from these PAPs do not blink. This technique can be extended to three or more adjacent or separate PAPs.

  In areas where the power of one PAP does not occupy the majority of the total received power (eg, areas not close to any PAP), location ambiguity can be further improved. All energy “bubbles” are the product of a three-dimensional standing wave pattern, which is formed by the phase of the PAP and the internal reflection of the warehouse. Multiple energy “bubbles” in regions that are not in close proximity to any PAP can be separated into subgroups by rotating the polarizations of all PAPs simultaneously. An energy “bubble” that relies heavily on the internal reflection of the warehouse is “off”, whereas an energy “bubble” that does not rely heavily on the internal reflection does not turn “off”. The difference between two groups of “bubbles” is maximized by 90 degrees of polarization rotation.

  Identify different subgroups of energy “bubbles” by observing which other energizable devices are “off” and which are no longer energized, using multiple other polarization rotation values You can also Using this subgroup separation, in addition to helping resolve RFID tag location ambiguity, it can also help improve connectivity maps in a manner similar to the PAP phase change procedure.

  By using the grouping technology of these energizable devices, it is possible to generate a connectivity map of the receiving device without ambiguity. Using the known location of the reference tag, a three-dimensional map of the physical location of all tags in the warehouse can be generated. FIG. 7 shows a method for determining the position of the energizable device.

  Specifically, at 222, the space is separated into a plurality of subspaces by selecting a switched beam setting with all PAPs turned on. At 224, the subspace is divided into a plurality of subgroups by sequentially turning off one or more PAPs. At 226, the subspace is further divided into subgroups by switching the polarization of all PAPs. In one embodiment, step 226 is performed after step 224. In another embodiment, one or both of steps 224 and 226 are performed simultaneously. At 228, a connectivity map is constructed by moving energy bubbles through the subspace by changing the relative phases of the plurality of PAPs for each subspace. In another embodiment, step 228 is performed on a subpopulation rather than a subspace. At 230, fix connectivity maps at multiple points in space using known locations of multiple reference receivers and various connectivity map results from multiple subspaces or multiple subpopulations. (decide.

  In FIG. 8, a method for improved wireless energy transfer includes, at 250, guiding a first energy beam formed by a plurality of PAP polarizers. At 252, the polarities of the first and second energy beams are aligned in the energizable device.

  In FIG. 9, a method for improved wireless energy transfer includes, at 260, directing an energy beam formed by the PAP to an energizable device. At 262, the polarity of each energy beam is aligned in the energizable device. In H.264, the planar area is divided into partial spaces. At 266, the energizable device is detected by scanning the energy beam along the scanning path in the subspace. At 268, a connectivity map is determined. At 270, the position of the receiving device and the proximity device relative to the reference device is interpolated.

Further Embodiment Examples The following are example embodiments that provide further explanations of various embodiment types in accordance with the concepts described herein, including those explicitly listed as at least some “EC” (combination examples). These examples are not mutually exclusive, comprehensive or restrictive, and the present invention is not limited to these example embodiments, and the scope of the claims to be issued and the equivalents thereof Including all possible modifications and variations.

EC1: Energy beam optimization method,
In the energizable device, from one of the plurality of PAPs, a plurality of transmission phases including an initial transmission phase in the first time slot, a second transmission phase in the second time slot, and a third Receiving an energy beam having a plurality of transmission phases including a third transmission phase in a time slot;
In the energizable device, each received signal strength indication (RSSI) of the transmission phase is stored,
When the received RSSI changes by a threshold, each stored RSSI level is received from the energizable device at the PAP;
A method for obtaining a reception amplitude and a reception phase of an energy beam of an initial transmission phase by PAP in an energizable device.

  EC2: The method of EC1, wherein the second transmission phase is shifted 90 degrees from the initial transmission phase and the third transmission phase is shifted 180 degrees from the initial transmission phase.

  EC3: The method of EC1, wherein the second transmission phase is shifted 180 degrees from the initial transmission phase and the third transmission phase is shifted 270 degrees from the initial transmission phase.

  EC4: The method of EC1, wherein the phase of the received energy beam is adjusted to be equal to the second received phase of the second energy beam transmitted by the second PAP.

EC5: a switched beam polarization alignment method,
Directing a first energy beam transmitted by a plurality of antennas coupled to the PAP by a Butler matrix towards the receiver;
In each of the plurality of antennas, the first polarization signal derived from the PAP is combined with the second polarization signal formed by rotating the first polarization signal. Aligning the first polarity of one energy beam with the second polarity of a second energy beam transmitted by another PAP.

EC6; antenna system,
A patch antenna including a dielectric substrate interposed between the resonance plate and the ground plate, and a first supply point and a second supply point;
A first variable gain amplifier (VGA) connected to the first supply point and configured to adjust a first amplitude of the signal;
A first phase shifter configured to adjust the phase of the signal interposed between the signal and the first VGA;
A second VGA connected to the second supply point and configured to adjust a second amplitude of the signal;
A system in which the patch antenna controls the tilted linear polarization of the signal.

  EC7: EC6 system in which the phase is not less than zero degrees and not more than 360 degrees.

EC8: switched beam polarization alignment system,
A patch antenna that controls the polarization of a signal including a dielectric substrate interposed between the resonance plate and the ground plate, a first supply point, and a second supply point; and is connected to the first supply point A first VGA configured to adjust the first amplitude of the signal; a first phase shifter configured to adjust the phase of the signal interposed between the signal and the first VGA; Four or more antenna systems each including a second VGA connected to a second supply point and configured to adjust a second amplitude of the signal;
A first crossing device coupled to the first antenna system pair;
A first hybrid coupler pair coupled to the first crossing device and the second antenna system pair;
A second crossing device coupled to the first hybrid coupler pair;
A second hybrid coupler pair coupled to the second crossing device and the first hybrid coupler pair;
A switch coupled to a second pair of hybrid couplers;
A phase shifter coupled between the output of the power access point and the switch;
Including system.

EC9: A method for determining a receiver position,
Dividing a planar region including a plurality of devices into a plurality of subspaces each defined by a beam position from a respective beam of a plurality of energy beams;
Of each of the plurality of devices by scanning a respective beam of the energy beam along a scanning path in the subspace to detect a change in energy received in each of at least some of the plurality of devices. Detecting the presence of at least some devices, wherein at least some of the plurality of devices include an energizable device and one or both of a proximity device and a reference device, wherein the reference device is within a planar region Having a predetermined position,
Determining the connectivity map by finding the respective position of each proximity device relative to the position of the receiving device;
A method of interpolating the physical position of a receiver and a proximity device relative to a reference device.

  EC10: The method of EC9, wherein the position of the receiving device is specified within one wavelength of each energy beam of the energy beam.

  EC11: The method of EC9, wherein each subspace is divided into narrower spaces by continuously stopping one energy beam and detecting the presence of the receiving device by a decrease in energy received at the receiving device.

  EC12: Each subspace continuously stops two physically adjacent energy beams and detects the presence of a receiver between two physically adjacent energy beams by a decrease in energy received at the receiver The method of EC9, which is further divided into narrow spaces.

  EC13: The method of EC9, wherein each subspace is divided into narrower spaces by rotating the polarity of all energy beams and detecting the presence of the receiving device by a decrease in the energy received at the receiving device.

  EC14: generating connectivity maps for multiple receivers in each subspace, and using known locations of the reference locations to determine known locations in the connectivity map, separating the space to be covered into subspaces Positioning and ambiguity resolution based on doing.

EC15: Separation of space into subspaces is achieved by dividing the region into N ² subspaces in the horizontal (orientation) plane using multiple switched beam antennas, where N is utilized from each PAP This is the number of beams in the horizontal plane that can be made.

EC16: Separation of space into subspaces can be extended to vertical (rising) coordinates that include M vertical beams and the total number of subspaces in three dimensions is M × N ² .

  EC17: Separation of space into subspaces can also be increased by sequentially turning off each PAP and separating the region into multiple near and far subspaces.

  EC18: Separation of space into subspaces can be further increased by sequentially turning off two or more adjacent or separated PAPs to separate the region into further subspaces.

  EC19: Separation of multiple spaces into subspaces can also be increased by sequentially adopting orthogonal polarizations to separate receivers that are not but adjacent.

  EC20: Separation of multiple spaces into subspaces can be further increased by sequentially adopting other values of polarization to separate nearby but not adjacent receivers.

  EC21: Connectivity map selects a subspace to be illuminated with a switched beam antenna, moves energy bubbles throughout the subspace by changing the relative phase of multiple PAPs, and turns off one or more PAPs Or by observing which receivers “flash” when the polarization is rotated.

  EC22: The connectivity map is spatially fixed at multiple points through known positions of the reference position.

  Although the invention has been described herein with reference to particular embodiments, various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. The specification and drawings are accordingly to be regarded in an illustrative sense rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention. Any benefit, advantage, or problem solution described herein with respect to a particular embodiment should not be construed as a critical, essential, or essential feature or element of any or all of the claims. .

  Unless stated otherwise, terms such as “first” and “second” are used to arbitrarily distinguish between the elements represented by these terms. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements.

10 Wireless energy transmission system 12 Internet of Things (IoT)
14a mobile phone 14b tablet 14c smart watch 14d stereo 14e computer 16a-c power access point (PAP)
18a-c energy beam 20a coherent energy bubble 22 range of PAP 24 communication medium 26a-d path 28 path 30 control module

Claims (20)

A system for improved wireless energy transfer,
A first power access point (PAP) configured to direct a first energy beam having a fundamental frequency and a first polarity to the energizable device;
Directing a second energy beam physically separated from the first PAP and having a wireless connection with the first PAP and having the fundamental frequency and a second polarity to the energizable device. A configured second PAP;
A plurality of polarizers of the first PAP form the first energy beam directed to the energizable device, and the first polarity is set to the second polarity in the energizable device. Configured to align,
The second PAP can receive a PAP signal via the wireless connection and further generate the fundamental frequency locally from the PAP signal.
A system characterized by that. Each of the polarizers is
A patch antenna including a dielectric substrate interposed between the resonance plate and the ground plate, and a first supply point and a second supply point;
A first variable gain amplifier (VGA) connected to the first supply point and configured to adjust a first amplitude of a signal;
A first phase shifter configured to adjust a phase of the signal between the signal and the first VGA;
A second VGA connected to the second supply point and configured to adjust a second amplitude of the signal;
The patch antenna controls polarization of the signal,
The system of claim 1. The first phase shifter is configured to shift the phase of the signal over a range from minus 90 degrees to plus 90 degrees.
The system according to claim 2. A second phase shifter between the signal and the second VGA is further included, and each of the first phase shifter and the second phase shifter increases the phase of the signal from minus 90 degrees to plus 90. Compound shift over a range of degrees,
The system according to claim 2. The number of the plurality of polarizers is divisible by 2, and each polarizer is connected to the antenna signal in a wight cross structure.
The system of claim 1. The number of the polarizers is 4,
A first crossing device coupled to the first pair of polarizers;
A first hybrid coupler pair coupled to the first crossing device and a second polarizer pair;
A second crossing device coupled to the first hybrid coupler pair;
A second pair of hybrid couplers coupled to the second crossing device and the first pair of hybrid couplers;
A switch coupled to the second pair of hybrid couplers;
A master phase shifter coupled between the antenna signal and the switch;
The system of claim 5 comprising: The first polarity is one of vertical, inclined, horizontal, circle, ellipse and inclined ellipse.
The system of claim 1. Optimizing alignment of the first polarity with the second polarity using a received signal strength indicator received by the first PAP from the energizable device;
The system of claim 1. The alignment optimization uses a phasor decomposition method,
The system according to claim 8. A method for improved wireless energy transfer comprising:
Directing a first energy beam having a fundamental frequency formed by a plurality of polarizers of a first power access point (PAP) towards the energizable device;
In each of the first PAP polarizers, combining a respective first polarization signal with a respective second polarization signal formed by rotating the respective first polarization signal. Thus, in the energizable device, the first polarity of the first energy beam is formed by a second PAP that is physically separated from the first PAP and has a wireless connection with the first PAP. Aligned with a second polarity of a second energy beam having the fundamental frequency, wherein the second PAP receives a PAP signal over the wireless connection and localizes the fundamental frequency from the PAP signal. To generate,
A method characterized by that. Each of the polarizers of the first PAP combines a rotated first polarization signal with the respective second polarization signal having a rotation different from the rotated first polarization signal;
The method of claim 10. The alignment of the first polarity with the second polarity is optimized based on a received signal strength indicator (RSSI) received by the energizable device;
The method of claim 10. The alignment uses a phasor decomposition method;
The method of claim 12. Both the first energy beam and the second energy beam sequentially move from the energizable device to another energizable device, and the alignment is performed by another RSSI received by the other energizable device. Optimized,
The method of claim 12. The alignment is simultaneously optimized for the energizable device and another energizable device by maximizing a minimum RSSI from each of the energizable device and the other energizable device.
The method of claim 12. A method for improved wireless energy transfer comprising:
A plurality of energy beams are directed to the energizable device, each energy beam having a fundamental frequency and formed by a respective power access point (PAP) having a plurality of polarizers, each PAP being physically transmitted from another PAP. Separated and having a wireless connection with the other PAP, one of the PAPs receiving a PAP signal over the wireless connection and locally generating a fundamental frequency from the PAP signal ,
Combining the respective first polarization signals with the respective second polarization signals in each of the polarizers of each respective PAP to align the polarities of each of the energy beams in the energizable device; Each second polarization signal is formed by rotating the respective first polarization signal,
Dividing a planar region including a plurality of energizable devices into a plurality of subspaces each defined by an energy beam position from a respective energy beam of the plurality of energy beams;
The respective energy beam of the energy beam is scanned along a scanning path in the subspace to change the energy received in each of at least some of the plurality of energizable devices. Detecting the presence of the at least some energizable devices of the plurality of energizable devices, wherein the at least some of the plurality of devices include a receiving device, a proximity device, and a reference Including one or both of the devices, wherein the reference device has a predetermined position in the planar area;
Determining a connectivity map by finding the respective position of each proximity device relative to the position of the receiving device;
Interpolating the physical position of the receiving device and the proximity device relative to the reference device;
A method characterized by that. The position of the receiver is identified within one wavelength of each energy beam of the energy beam;
The method of claim 16. Each subspace is divided into a narrower space by continuously stopping one energy beam and detecting the presence of the receiver by the reduction in the energy received at the receiver.
The method of claim 16. Each subspace continuously stops two physically adjacent energy beams and detects the presence of a receiver between the two physically adjacent energy beams by the decrease in the energy received at the receiver To be further divided into narrow spaces,
The method of claim 16. Each subspace is further divided into narrow spaces by rotating the polarity of all the energy beams and detecting the presence of the receiver by the reduction in energy received at the receiver.
The method of claim 16.

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