Data Link for Resonant Inductive Wireless Charging

Abstract

To provide a full duplex, low latency, near field data link that controls a resonant induction, wireless power transfer system for recharging batteries.SOLUTION: A vehicle-side assembly (VA) 1261 includes one or more charging coils and a first full duplex inductively coupled data communication system. The first full duplex inductively coupled data communication system communicates with a ground assembly (GA) 1260 including one or more charging coils and a second full duplex inductively coupled data communications system. The charging coils of the GA and the VA are selectively enabled based on geometric positioning of the VA relative to the GA for charging. As appropriate, the transmit / receive system of the GA and / or the VA are adjusted to be of the same type to enable communication of charging management and control data between the ground assembly and the vehicle assembly during charging.SELECTED DRAWING: Figure 12b

Description

[Technical Field]

[0001] The wireless power transfer system, a full-duplex near-field data link for controlling resonant induction, is used to charge electric vehicles. The coherent repeater configuration enables synchronous detection to reject interference and ensures rejection of signals from nearby and adjacent vehicles.

[0002] Inductive power transmission has many important applications across many industries and markets. A resonant inductive wireless power device can be viewed as a switch-mode DC-DC power supply with a large air-gap transformer that separates and insulates the input and output sections of the power supply. Because the output current is controlled by adjusting input-side parameters, a method is needed to communicate the output parameters to the input-side control circuitry. Traditional isolated switch-mode power supplies use optocouplers or coupling transformers to communicate across the isolation barrier, but these traditional methods are useless when large physical gaps exist. Acoustic and optical communication across the power transmission gap is possible in principle, but in practice it is inadequate when exposed to mud, road debris, snow, ice, and standing water. Communication across the power transmission gap is possible by modulating the impedance of the receiving coil and detecting the variations in voltage and current induced in the primary coil. However, due to the typically low operating frequencies employed by the resonant inductive wireless power transfer devices and the moderate to high loaded Q of the primary and secondary coils of such resonant inductive wireless power transfer systems, the available data communication bandwidth is severely limited and full-duplex communication is difficult to implement.

[0003] Therefore, data communication systems implemented in radio frequencies are preferred because they do not suffer from the above problems. However, conventional radio frequency data communication systems are deficient in several aspects. Half-duplex systems transmit in only one direction, but by quickly changing the transmission direction, they create a data link that functions as a full-duplex link. Buffering or waiting for transmitted data introduces large and variable transmission delays that are particularly undesirable when placed in the feedback path of a control system, as they can cause the control system to become unstable.

[0004] Conventional superheterodyne receivers typically require fairly good intermediate frequency filters to provide off-channel interference rejection, but such filters tend to be expensive and not suitable for monolithic integration.

[0005] Furthermore, conventional wireless data links do not inherently distinguish between other nearby data links of the same type, meaning that conventional wireless data links used to mediate wireless charging of electric vehicles often respond to wireless commands issued by charging devices in nearby or adjacent parking stalls, an operation that significantly complicates unambiguous vehicle identification and subsequent wireless charging control. Summary of the Invention

[0006] The systems and methods described herein address these and other limitations of selected technologies by implementing a coherent, full-duplex radio frequency data link that relies on near-field inductive coupling, as opposed to far-field propagation as in conventional systems to limit effective communication range, uses synchronous detection to reject off-channel and some co-channel interference without advanced frequency domain filtering, and further uses a coherent repeater configuration to reliably identify the data link transmitting and receiving equipment pair.

[0007] In a sample embodiment, two devices are provided, one associated with the ground-side wireless power transmission device and the other associated with the vehicle-side wireless power transmission device. A crystal-controlled reference oscillator located in the ground-side device provides a common base for coherently generating all radio frequency signals necessary for transmission and detection. Because this is a full-duplex communication device, there are two independent transmit and receive links: a forward link from the ground side to the vehicle-side device and a return link from the vehicle side to the ground-side device. The vehicle-side loop antenna is typically located under the conductive underbody of the vehicle and parallel to the ground plane.

[0008] The forward link transmission signal is derived from the reference oscillator. Serial data is imposed onto the forward link carrier by the modulator. Transmission occurs between two electrically small loop antennas with significant mutual inductive coupling, separated by a wavelength much shorter than that at the forward link operating frequency. At the vehicle side of the forward link, the received signal is detected by a homodyne detector, which extracts the signal's carrier and uses it as a detection reference for a synchronous detector. The extracted carrier is frequency multiplied and used as the carrier for the return link, with the return link data imposed on the carrier by a second modulator. Return link transmission occurs, as before, by near-field inductive coupling between two closely spaced electrically small loop antennas. A synchronous detector on the ground side of the link extracts the return link data using a frequency-multiplied version of the original reference oscillator signal as a detection reference. Link modulation in both directions can be amplitude modulation, phase modulation, or a combination of both.

[0009] Because the forward link carrier, forward link detection reference, return link carrier, and return link detection reference are all derived from the same reference oscillator, coherence of these four critical signals is guaranteed by design. Complex frequency acquisition and synchronization circuitry is not required. Furthermore, manufacturing tolerances between reference oscillators and environmental frequency variations prevent link signals from devices located in adjacent parking spaces from interfering with each other and therefore being subject to synchronous detection. Further rejection of link signals originating from devices and vehicles in adjacent parking spaces results from attenuation that occurs when the link transmission wavelength exceeds the separation distance from the vehicle underbody to the ground plane, with the vehicle underbody and the ground plane acting as the two plates of a waveguide below the guided propagation cutoff frequency.

[0010] According to a first aspect, a charging system is provided, including a first full-duplex inductively coupled data communication system having a first coil assembly with a charging coil and a first transceiver system configured to transmit a first signal via a first inductive link and receive a second signal via a second inductive link; and a second full-duplex inductively coupled data communication system having a second coil assembly with a charging coil and a second transceiver system configured to receive the first signal via the first inductive link and transmit the second signal via the second inductive link. In a sample embodiment, the first and second transceiver systems are adapted to be selectable from at least one of hardware, software, and firmware configurations adapted to modulate an output signal and demodulate an input signal. The charging coil of the first coil assembly is configured to be positioned parallel to the charging coil of the second coil assembly to receive a charging signal during charging, allowing the charging coil to selectively conform to a shape of the second coil assembly during charging.

[0011] In a sample embodiment, the first transceiver system has a processor that processes data from at least one of the first coil assembly and an external system to transmit to the second coil assembly, and processes data received from the second coil assembly to deliver to at least one of the first coil assembly and an external system for processing. In a sample embodiment, the processor disables the charging signal when a fault event is detected by the first coil assembly or received from the second coil assembly.

[0012] In another sample embodiment, the second transceiver system includes a processor that processes and transmits at least one of commands and data from the second coil assembly and an external system to the first coil assembly, and processes and distributes data received from the first coil assembly for distribution to the second coil assembly and at least one of the external systems. In a sample embodiment, the second coil assembly further includes a digital interface, and the processor provides measurements related to the first signal, the second signal, and the charging signal to the digital interface. The measurements include at least one of signal strength, bit error rate, energy per bit to spectrum noise density ratio, frequency, and amplitude and phase shift at first and second antenna structures of the first coil assembly and second coil assembly. In the sample embodiment, the external system includes an external processor. In such an embodiment, the measurements are distributed to the external processor via the digital interface for at least one of alignment detection and closed-loop charging system management and control. The external processor may provide near real-time voltage and current measurements of the second coil assembly, thermal measurements of the second coil assembly, changes to the Z-gap, fault alerts of the first coil assembly or the second coil assembly, alerts regarding performance events during charging, and additional sensed data related to the second coil assembly to the processor for transmission.

[0013] In other sample embodiments, the first signal and the second signal are configured as either narrowband or wideband signals depending on the stage of the charging cycle or whether a signal quality threshold has been exceeded.

[0014] In yet another sample embodiment, the first signal and the second signal are configured as asynchronous spread spectrum signals. In such an embodiment, the first and second transmit / receive systems each include a direct sequence spread spectrum system that transmits complementary code sequences that enable the first and second transmit / receive systems to distinguish between signals and co-channel interference.

[0015] In a sample embodiment, the hardware, software, and / or firmware is adapted to modulate the output signal using at least two of amplitude modulation, phase modulation, frequency modulation, orthogonal frequency division multiplexing (OFDM), and spread spectrum techniques, which may include at least one of direct sequence spread spectrum, chirp spread spectrum (CSS), binary quadrature modulation (BOK), and frequency hopping.

[0016] In yet another sample embodiment, the first and second transceiver systems each include a receiver, an analog-to-digital converter, a digital processor for processing data from at least one of the first coil assemblies and for processing data received from the second coil assembly for delivery to the external system for processing, a digital-to-analog converter, and a transmitter. In the sample embodiment, the analog-to-digital converter and digital-to-analog converter are implemented as separate integrated circuits, and the digital processor is implemented as a field programmable gate array. Also, the analog-to-digital converter, digital processor, and digital-to-analog converter may be implemented as firmware resident in an application-specific integrated circuit (ASIC). In the sample embodiment, the digital processor of each transceiver system processes input data for transmission and processes data received from the other transceiver system using software structures implemented in the digital processor. The first and second transceiver systems optionally include at least one bandpass filter.

[0017] According to a second aspect, a method for charging a vehicle is provided, comprising: positioning a vehicle assembly relative to a ground assembly to receive a charging signal; the vehicle assembly having one or more charging coils, each charging coil having a first full-duplex inductively coupled data communication system with a first transmit / receive system configured to receive a first signal via a first inductive link and transmit a second signal via a second inductive link; and the ground assembly having one or more charging coils, each charging coil having a second full-duplex inductively coupled data communication system with a second transmit / receive system configured to transmit the first signal via the first inductive link and receive a second signal via the second inductive link. The charging coils of the ground assembly and the vehicle assembly are selectively enabled based on the geometric orientation of the vehicle assembly relative to the ground assembly for charging. At least one of the first transmit / receive system and the second transmit / receive system is selected to have the same type of hardware, software, and / or firmware adapted to modulate an output signal and demodulate an input signal in the same manner as one of the first and second transmit / receive systems.

[0018] In a sample embodiment, the first transceiver system and the second transceiver system are adapted to modulate the output signals using at least two of amplitude modulation, phase modulation, frequency modulation, orthogonal frequency division multiplexing (OFDM), and spread spectrum techniques, which may include at least one of direct sequence spread spectrum, chirp spread spectrum (CSS), binary quadrature modulation (BOK), and frequency hopping.

[0019] In another sample embodiment, at least one of software updates, diagnostic or telemetry information, and passenger entertainment service data is communicated between the ground assembly and the vehicle assembly via first and second inductive links during charging. If a fault event is detected by or received from the ground assembly, the charging signal may be disabled.

[0020] In another sample embodiment, the first transceiver system processes and transmits at least one of commands and data from the vehicle assembly and an external system to the ground assembly, and processes and distributes data received from the ground assembly to at least one of the vehicle assembly and the external system. Measurements related to the first signal, the second signal, and the charging signal are also provided to a digital interface for processing. The measurements may include at least one of signal strength, energy per bit to spectrum noise density ratio, frequency, and amplitude and phase shift at first and second antenna structures of the vehicle assembly and ground assembly. The measurements are distributed via the digital interface to an external processor for at least one of alignment detection and closed-loop charging system management and control.

[0021] In yet another sample embodiment, the method includes transmitting at least one of near real-time voltage and current measurements of the vehicle assembly, thermal measurements of the vehicle assembly, Z-gap changes due to loading or unloading of a vehicle including the vehicle assembly, fault alerts for a ground assembly or vehicle assembly, alerts regarding operational events during charging, and additional sensing data related to the vehicle assembly from the vehicle assembly to the ground assembly.

[0022] In yet another sample embodiment, the method includes configuring the first signal and the second signal as narrowband or wideband signals depending on a stage of a charging cycle or whether a signal quality exceeds a threshold.

[0023] In yet another sample embodiment, the method includes configuring the first signal and the second signal as asynchronous spread spectrum signals, and complementary code sequences are transmitted between the first and second transmit / receive systems that enable the first and second transmit / receive systems to distinguish between the signals and co-channel interference.

[0024] According to a third aspect, there is provided a vehicle charging system including a clustered ground assembly having at least two independent coils, each coil having a first full-duplex inductively coupled data communication system including a transceiver system for transmitting a first signal via a first inductive link and receiving a second signal from a vehicle via a second inductive link, the first and second signals being communicated between the clustered ground assemblies and the vehicle during charging of the vehicle. The clustered ground assembly may include individual ground assemblies mounted in a successive manner in close proximity to form a single macro ground assembly.

[0025] In a sample embodiment, the vehicle being charged has two or more vehicle assemblies mounted to enable higher power transfer than can be achieved with a single vehicle assembly, and the clustered ground assembly includes a coil configured to match the shape of the two or more vehicle assemblies.

[0026] In a further sample embodiment, the vehicle to be charged is equipped with a clustered vehicle assembly shaped to match the clustered ground assembly, the clustered vehicle assembly including at least two independent coils, each coil having a second full-duplex inductive coupling data communication system having a transceiver system for transmitting the second signal via a second inductive link and receiving the first signal from the clustered ground assembly via the first inductive link, the first and second signals being communicated between the clustered ground assembly and the clustered vehicle assembly during charging of the vehicle.

[0027] The clustered vehicle assemblies and the clustered ground assemblies each include two or more functionally identical assemblies, each functionally identical assembly including a magnetic induction antenna and a common resonant induction coil unit. [Brief explanation of the drawings]

[0028] The foregoing and other beneficial features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings. [Figure 1] FIG. 1 shows a conceptual diagram of a sample embodiment of ground-side and vehicle-side transmission devices. [Figure 2] FIG. 2 shows a sample embodiment of a full-duplex radio frequency data link. [Figure 3] FIG. 3 illustrates the subharmonic waveform employed by the sample embodiment of FIG. 2 above to avoid self-interference. [Figure 4] FIG. 4 shows a representation of the digital amplitude shift keying used in the sample embodiment of FIG. [Figure 5] FIG. 5 shows an embodiment of the subharmonic generating circuit that generates the waveform shown in FIG. [Figure 6] FIG. 6 shows a representation of the digital amplitude shift keying used in the embodiment of FIG. [Figure 7] FIG. 7 shows an embodiment of a receiver level detection circuit. [Figure 8] FIG. 8 shows an embodiment of an apparatus for self-interference cancellation. [Figure 9] FIG. 9 illustrates an embodiment of dynamic charging using the communication methodology described herein. [Figure 10] FIG. 10 shows an example of a clustered deployment of transmission devices in a sample embodiment. [Figure 11a]FIG. 11a illustrates the signaling and components used by an inductively coupled communication system (ICCS) of a wireless power transfer (WPT) system in a sample embodiment. [Figure 11b] FIG. 11b shows an example of a diversity receiver antenna for an inductively coupled communication system (ICCS) of the wireless power transfer (WPT) system. [Figure 12a] Figure 12a shows the functional elements of the ICCS in a sample embodiment. [Figure 12b] FIG. 12b shows a sample hardware embodiment of the ICCS including the vehicle-side assembly and the ground-side assembly. [Figure 13a] FIG. 13a shows an overhead view of wireless charging stations implemented in a parking lot deployed in a single row geographical layout in a sample embodiment. [Figure 13b] FIG. 13b shows an overhead view of wireless charging stations implemented in a parking lot deployed in a two-row geographical arrangement in a sample embodiment. [Figure 14] FIG. 14 shows an example of a highway where dynamic charging is enabled in a sample embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0029] Although sample embodiments for use in charging electric vehicles are described with respect to Figures 1-14, those skilled in the art will appreciate that the teachings provided herein can be used in other non-vehicle resonant magnetic induction wireless power transfer systems, and such embodiments are intended to be within the scope of this disclosure.

[0030] FIG. 1 shows a conceptual diagram of a sample embodiment in which two devices are provided: a ground-side device associated with a ground-side wireless power transmission device, and a vehicle-side device associated with a vehicle-side wireless power reception device. The data link shown in FIG. 1 is implemented, for example, in the coil alignment error detection device described in U.S. Patent No. 10,193,400. As shown in FIG. 1, the ground-side device includes a frequency multiplier 10, a data modulator 20 that receives input data for transmission, and a synchronous detector 30 that receives data on a return link from the vehicle-side device and provides output data. Similarly, the vehicle-side device includes a frequency multiplier 40, a homodyne detector 50 that receives data on a transmit link from the ground-side device, and a modulator 60 that transmits data on the transmit link to the ground-side device. Loop antennas 70 and 70' of the ground-side device communicate wirelessly by induction with loop antennas 80 and 80' of the vehicle-side device in a conventional manner. A crystal-controlled reference oscillator 90 located in the ground-side device provides a common basis for coherent generation of all radio frequency signals required for transmission and detection. Since this is a full-duplex communication device, there are two independent transmit and receive links: a transmit link from the ground side to the vehicle-side device, and a return link from the vehicle side to the ground-side device. The vehicle-side loop antennas 80 and 80' are typically located under the conductive underbody of the vehicle and are parallel to the ground-side loop antennas 70 and 70'.

[0031] The system and method described herein and illustrated in FIG. 1 differs from conventional wireless data communications in the following ways: The communication path is full-duplex and bidirectional, and includes a transmission path from the ground-side device to the vehicle-side device and a second return data path for transmitting data from the vehicle-side device to the ground-side device. The electronic communication mechanism is a near-field, magnetic coupling between two antennas 707, 80 and 70', 80' that are sensitive to colliding magnetic energy, rather than the far-field, free-space propagation of conventional radio frequency data communication. The transmit path signal carrier provides the basis for generating a secondary path signal by frequency multiplication, which means that the secondary path signal is harmonically related to the transmit path signal, avoiding the technical difficulties of deriving a synchronous and coherent reference signal for return path synchronous detection. Furthermore, the coherent and harmonically related transmit path signals allow for simple and clear cancellation of co-channel and off-channel interference emanating from other identical devices in adjacent parking stalls and cancellation of data link signals.

[0032] In the exemplary embodiment shown in FIG. 2, the transmit path frequency from reference oscillator 90 is 13.560 MHz. The return path operates at 40.680 MHz, the third harmonic of the transmit path. Both frequencies are internationally allocated for non-telecommunications Industrial, Scientific, and Medical (ISM) use. Telecommunications use is permitted in ISM channels with relaxed regulatory requirements, but interference from all other ISM channel users is acceptable. The non-radiative, near-field nature of the coherent transponder system described herein, along with the waveguide under the blocking structure provided by the vehicle's conductive underbody and the ground plane in a typical application, makes the described system highly resistant to co-channel interference and, for this reason, suitable for use in ISM-allocated frequencies.

[0033] Generation of the transmit path signal begins with a reference crystal oscillator 90 operating at a frequency of 13.560 MHz. This signal is applied to a waveform generation stage including a third harmonic cancellation circuit 22 and an amplitude shift modulator 24, which together comprise the modulator 20 of FIG. 1. Of course, other types of modulators, such as a frequency shift modulator or a QPSK modulator, can be used. In an exemplary embodiment, the amplitude shift modulator 24 generates the rectangular waveform shown in FIG. 3, where T is the waveform period and the third harmonic power is approximately zero. A small loop antenna 70 with a balanced feed serves as the transmit path communication antenna, and a second, vehicle-mounted, balanced feed, small loop antenna 80 is used as the transmit path receive antenna. Both antennas 70, 80 are much smaller than a wavelength at the operating frequency, making them inadequate as free-space transmit antennas. However, when physically close together, the two small loop antennas 70, 80 have significant mutual magnetic field coupling, enabling both transmit and return communication paths without significant free-space propagation.

[0034] From "Engineering Mathematics Handbook, Third Edition, Tuma, Jan., McGraw-Hill 1987 ISBN 0-07-065443-3," the Fourier series coefficients for the modified sine waveform shown in Figure 3 are as follows:

[0035]

number

[0036] Of the first 20 Fourier series coefficients, all but six are zero. The non-zero coefficients are the fifth and seventh, suppressed to -14 dB and -16.9 dB, the eleventh and thirteenth, suppressed to -16.9 dB and -20.8 dB, and the seventeenth and nineteenth, suppressed to -22.9 dB and -25.5 dB. While a mathematically ideal waveform would have infinite third-harmonic suppression, practical implementations, due to unequal logic propagation delays between 0 and 1 and between 1 and 0, as well as other minor waveform asymmetries, do not achieve infinite harmonic cancellation. Nevertheless, the waveform of Figure 3 produced by the third-harmonic cancellation circuit 22 with the circuit shown in Figure 5, has excellent third-harmonic suppression (third-harmonic energy approaches zero) and detection in the transmit and return paths. Any remaining residual third-harmonic energy can be further suppressed using conventional harmonic filtering techniques, if necessary.

[0037] The low third harmonic generation circuit shown in Figure 5 consists of a walking ring counter comprised of three D flip-flops 102, 104, 106 clocked at six times the desired output frequency, derived from the 13.560 MHz frequency from the reference oscillator 90 by a PLL frequency multiplier 108. A pair of NAND gates 110, 112 decodes the walking ring counter to generate the desired square wave that drives the transmit link loop antenna 70 via two transistors 114, 116 arranged in a symmetric push-pull configuration. The inductance of the two radio frequency chokes 118, 120 connected to a voltage source 122, combined with the inductance of the loop antenna 70 and the antenna resonating capacitor 124 shown in Figure 5, form a resonant circuit that provides suppression of residual harmonic energy, particularly the third harmonic in the illustrated embodiment.

[0038] As shown in Figure 2, in an exemplary embodiment, amplitude shift keying (ASK) modulation is imposed on the transmit link carrier by amplitude shift modulator 24 by varying the value of the transmit link transmit stage supply voltage. A logic one bit is encoded as full signal amplitude, with the transmit stage operating at full supply voltage. A logic zero bit is encoded as half the full signal amplitude, with the transmit stage operating at a reduced power supply voltage. Varying the transmitter stage supply voltage in this manner produces the transmit waveform shown in Figure 4.

[0039] At the vehicle end of the transmit link, a variable gain control amplifier 52 increases the amplitude of the received signal from the loop antenna 80. Because the received signal has a non-zero value even for logic-zero bits, a 13.56 MHz carrier is always present (see Figure 4). A portion of the amplified received signal is applied to a limiting amplifier 54, which removes received signal amplitude variations, both those introduced by amplitude data modulation and those caused by occasional changes in the magnetic coupling between the two transmit path loop antennas 70, 80. The output of the limiting amplifier 54 is a constant amplitude square wave that indicates the instantaneous polarity of the received signal. The portion of the variable gain amplifier output not applied to the limiting amplifier 54 is applied to one input of a multiplicative mixer 56. The output of the limiting amplifier 54 drives the other mixer input. The limiting amplifier 54 and the mixer 56 comprise the homodyne detector 50, from which the input signal carrier is extracted and used to synchronously detect the input signal. To achieve the full benefit of coherent detection, the propagation delay of the limiting amplifier 54 is negligible or compensated for. The output of the homodyne detector 50 corresponds to a full-wave rectification of the incoming amplitude-modulated signal. Resistor-capacitor low-pass filtering removes twice the carrier frequency ripple, leaving a DC voltage whose amplitude varies according to the applied serial digital modulation. The carrier-ripple filtered post-homodyne detector signal is applied to a level detection circuit 59, which feeds an automatic gain control (AGC) control loop 58 and also extracts the transmit path serial data by amplitude level detection. Its implementation is described in more detail below with reference to FIG. 7.

[0040] The transmit path carrier recovered by the limiting amplifier 54 is applied to a frequency tripler 42 implemented as a pulse generator, followed by a filter, or equivalently, first through a crystal filter 44, followed by a phase-locked loop to avoid frequency conflicts in the presence of a sufficiently strong transmit link signal. The resulting 40.680 MHz carrier is applied to a second amplitude shift modulator 62, using 100% and 50% modulation levels as before, to encode serial digital data on the return data path. The return path amplitude shift modulator 62 drives a small resonant loop antenna 80' as before, except that elements 102-112 of FIG. 5 are not required.

[0041] The ground side of the return link includes an antenna 70' and a small resonant closed-loop receiving amplifier 32 controlled by an automatic gain control (AGC) circuit 34. Coherent detection of the received return path signal is implemented by generating a 40.680 MHz coherent detection reference signal by means of frequency tripling. While the frequency error of the coherent detection reference signal is guaranteed to be zero by the overall design of the system, zero phase error is not guaranteed and is achieved using quadrature channel phase detection and phase-locked closed-loop control of a phase adjuster stage. Placing the phase adjuster stage (phase adjuster 12) before rather than after the frequency tripler 14 means that the total phase adjustment control range needs to exceed 120 degrees, rather than the full 360 degrees required by the coherent detector 30 to ensure phase-locked detection. To facilitate generation of the quadrature reference signal at 40.680 MHz, the ground side 13.560 MHz signal from the crystal oscillator 90 is multiplied by the frequency tripler 14, which outputs two square waves offset by 90 degrees. The frequency tripler 14 is implemented by a six-phase, phase-locked, quadrature frequency multiplier coefficient followed by a quadrature division by two circuits including D flip-flops 130, 132 to obtain I and Q synchronous detection reference signals, as shown in Figure 6. It will be appreciated that when the Q channel signal output at 17 is equal to 0V, there is no phase error. However, if the output at 17 is not 0V, there is a phase error, and the phase-locked closed-loop operation of phase adjuster 12 functions to drive the phase difference to zero.

[0042] The variable phase adjustment circuit 12 is implemented as a series of capacitively loaded logic inverters with a variable supply voltage. The capacitive load increases the propagation delay from the inverter input to the inverter output. Increasing the supply voltage decreases the inverter's propagation delay, thereby decreasing the inverter's phase adjustment. A conventional phase-locking loop formed by the Q-channel mixer 17 and associated adjustment filter 16 drives the Q-channel output of the synchronous detector 30 to zero, thereby ensuring proper phase synchronization for the I-channel amplitude detection.

[0043] The I-channel mixer 38 of the synchronous detector 36 mixes the output of amplifier 32 with the I-channel output of frequency tripler 14, thereby providing the input signal to the level detection circuit 36. The vehicle-side transmit path, level detection circuit 59 is identical to the installation-side return path, level detection circuit 36, except that the former includes the carrier detection function and an associated voltage comparator 138 (FIG. 7) which detects the presence of the return path signal.

[0044] FIG. 7 shows an embodiment of the receive-side level detection circuit 36. A peak hold capacitor 344, driven by a full-wave precision rectifier 136, holds the detected maximum voltage level, which is then held constant by the AGC circuit 34 (FIG. 2). The AGC-amplitude-stabilized peak detection voltage provides the reference voltage for the carrier detection voltage comparator 140 via an R-2R-R resistor divider 142, which sets the reference voltage for the 1-0 serial, binary detection voltage comparator 138 and the voltage comparator reference voltages at 25% and 75%, respectively, of the peak value of the detected waveform shown in FIG. 4. The carrier detection voltage comparator 140 provides a rapid indication of vehicle-side faults. In the event of a vehicle-side fault, such as sudden, unexpected load shedding, the return link carrier is immediately disabled. The ground-side device detects the carrier removal delayed only by the pre- and post-detection filter delays and immediately terminates wireless power transmission. The full value of the peak hold function is applied to the AGC integrator 144, which adjusts the gain of the AGC amplifier 34, and therefore the gain of amplifier 32, to maintain the voltage on the peak hold capacitor 134 equal to the voltage of the AGC set point 146. The conventional precision rectifier 136 produces an output voltage proportional to the absolute value of the input voltage and consists of one or more small signal diodes placed in the operational amplifier feedback path, effectively canceling the diode transmit voltage drop, thereby enabling precision rectification of low level signals with minimal error.

[0045] Alternatively, return link synchronous detection can be performed by utilizing coherent, but not phase-locked, I and Q detection channels. Amplitude and phase modulation can be extracted in the conventional manner, where the amplitude is the root mean square of the I and Q channels and the phase angle is the arctangent of the ratio of the I and Q channels. In this alternative embodiment, the phase shifting and phase locking circuitry is not required.

[0046] 1 and 2 show four loop antennas: a pair of transmit and receive antennas 70, 80 for the transmit link and a second pair of antennas 70', 80' for the return link. In an alternative embodiment, the pair of transmit and return link antennas can be combined into a single loop antenna with a conventional antenna duplexer to separate and isolate the transmit and receive link signals. Similarly, one or both data link signals can be multiplexed onto an auxiliary electromagnetic structure, such as the wireless power transfer coil or an eddy current generating coil that is part of the coil alignment error detection device described in U.S. Pat. No. 10,193,400.

[0047] For reasons of simplicity and cost reduction, it is desirable for the transmit and return paths to share a common antenna structure. The challenge of combining the transmit and receive path signals from each other and other electrical signals is the problem faced by combining the functions into a single antenna structure. Typically, there are two general methods for implementing signal combining: isolation and routing. The first method uses hybrid transformers, hybrid couplers, or directional couplers that differentiate transmit and return path signals by the direction of signal flow. The second method relies on frequency-selective filters that differentiate signals based on frequency. Frequency-selective multiplexers can be implemented as LC lumped components, distributed components, or monolithic circuits containing multiple resonating and connecting elements. A frequency-division multiplexing function block can combine both signal direction and signal frequency discrimination.

[0048] The performance of the signal multiplexer function block (circuit) can be improved by adding the electronic signal cancellation function block (circuit), as shown in FIG. 8. The electronic signal cancellation function block (circuit) is installed in the path between the common transmit / return path antenna and the receiver. The common antenna is connected to port 202 of signal splitter 204. One splitter output is sent to the input port of mixer 206 by isolation amplifier 208. A sample of the signal to be canceled is applied to port 210, and the applied signal is adjusted to be in phase by variable phase adjuster 212 and applied to the local oscillator port of mixer 206 by limiting amplifier 214. The output of mixer 206 is applied to loop filter 216 and then to the control port of variable phase shifter 212. Components 212, 214, 206, and 216 form a phase-controlled loop that ensures the cancellation signal is 90 degrees out of phase with the unwanted signal component applied to port 202. Zero phase error corresponds to zero DC voltage at the output of mixer 206.

[0049] As shown in FIG. 8, the second output of splitter 204 is sent to combiner 218 by isolation amplifier 220. As shown, signal combiner 218, splitter 222, isolation amplifier 224, mixer 226, loop filter 228, and attenuator 230 together form an amplitude control loop. A portion of the quadrature sample signal output by phase adjuster 212 is applied to the fixed 90-degree phase adjuster 232 to create a 180-degree out-of-phase version of the cancellation signal, which passes through controlled attenuator 230 and enters signal combiner 218. If the cancellation signal has the correct amplitude, complete cancellation of the unwanted signal is achieved. A portion of the combiner 218 output signal is directed to the receiver input 234 via splitter 222. Another portion is directed via isolation amplifier 224 to the signal port of mixer 226, which functions as a coherent amplitude detector driven by the unattenuated portion of the 180-degree out-of-phase cancellation signal. The output of mixer 226 passes through loop filter 228, which controls the variable attenuator 230. Those skilled in the art will appreciate that zero cancellation signal amplitude error corresponds to zero DC voltage at the output of mixer 226.

[0050] During operation, when a vehicle approaches a wireless charging station, communication is established before charging begins. Once charging begins, full-duplex communication is used to mediate and control multiple aspects of the wireless power transfer operation, including monitoring transferred power levels, output voltage, current, and proper system operation. To establish control communication, the ground equipment can continuously or periodically emit a transmit path signal while listening for a vehicle-generated return path signal. Duplex communication begins upon detection of a vehicle-generated reverse path signal. Alternatively, the vehicle-side electronics can initially contact a return path signal temporarily derived from a temporary crystal oscillator (not shown) instead of the typically used carrier signal, which is recovered by the homodyne detector 50 and non-coherently detected by the ground-side electronics. Upon ground-side reception of the vehicle signal, the ground-side equipment emits a forward path signal. For vehicle-side communication initiation, the vehicle-side equipment disables the temporary crystal oscillator and returns to coherent transponder operation upon successful homodyne detection and carrier recovery.

[0051] Both of the above initiation methods rely on the emission of a forward or reverse path signal. Communications can also be advantageously initiated without a forward or reverse path emission. In an exemplary embodiment, the ground equipment detects a change in the impedance of the wireless power transmission coil caused by an overhead vehicle and responds by emitting a forward path signal. This embodiment reduces or eliminates unnecessary signal emissions and is advantageous in some regulatory environments. In addition to the wireless power transmission coil, the initiation impedance change can also be detected by the coil alignment auxiliary coil or the near-field communication antenna. In addition to impedance changes, changes in mutual impedance between isolated electromagnetic elements may also be used to initiate communications.

[0052] In the exemplary embodiment described herein, the reverse signal at 40.680 MHz is a simple integer multiple of the forward signal frequency of 13.560 MHz, and both signals are within the existing internationally designated ISM (Industrial, Scientific, and Medical) frequency allocation. Other frequencies and frequency pairs with non-integer frequency ratios can also be used. For example, two international ISM frequency bands with center frequencies of 2450 MHz and 5800 MHz can also be used. The coherent transponder architecture described herein, combined with conventional phase-locked loop technology, generates a 5800 MHz signal that is frequency-locked with a 2450 MHz signal with a frequency ratio M / N of 116 / 49, where M = 5800 MHz and N = 2450 MHz. Other combinations of ISM and non-ISM frequency band frequencies, frequency pairs with other integer or rational fraction frequencies, and multiple simultaneous transmit and receive carrier frequencies are also possible. For example, multiple return path data channels may be used, each transmitting data at a different M / N multiple of the transmission frequency of the first inductive link, where M and N are integers. Full-duplex frequency coherent communication is also possible with the ground and the remote device linked by far-field, as opposed to near-field, propagation.

[0053] Dynamic Charging Dynamic electric vehicle charging is a special case of powering an electric vehicle while it is in motion. As shown in FIG. 9, this use of dynamic charging is achieved using resonant magnetic induction, in which multiple independent transmitters 300 are installed along a roadway in a linear array and energized in a controlled sequence as target vehicles 310, 312 move across the linear array 300. Dynamic charging can be achieved either when there is only one vehicle 310 moving across the array of transmitters 300, or, in a more realistic scenario, when there are multiple electric vehicles 310, 312 of different types, speeds, and power requirements moving across the array of transmitters 300. In the latter case, the energization sequence of specific transmitters 300 will be variable within the array and dependent on the various vehicle types and their movements, inherently unpredictable factors. Therefore, the technical requirements of dynamic charging pose special technical challenges. The above system solves several problems of dynamic charging, listed below.

[0054] The most serious problem with dynamic charging is the need for vehicle-to-vehicle and ground-to-vehicle communications, which transfer discrete, high-speed, highly discernible, and reliable data as a requirement for command and control of the charging system. This data is necessary to operate the charging system as one or more vehicles may pass through a series of arrays of inductive power transmitters embedded in the ground.

[0055] As shown in Figure 9, an array of inductive power transmitters 300 is installed under a roadway, with each transmitter 300 arranged in a serial array along the longitudinal axis of the roadway. The intent is to provide a length of roadway that, when driven by an electric vehicle 310, 312, can provide power to the vehicle 310, 312 moving on the linear array of inductive transmitters 300. Desirably, only the transmitters 300 directly below the vehicle receiver are energized. The transmitters 300 without a vehicle above them should remain inactive (i.e., not energized).

[0056] Whether in the dynamic charging mode described here for all examples of inductive power transfer, or the simpler stationary charging case described above where a vehicle equipped with a single power receiver is parked and remains motionless over a single power transmitter embedded in the roadway, communication occurs between the vehicle-mounted receiver and the ground-mounted transmitter. This is suitable for vehicle identification, energy purchase billing, current and voltage regulation, resonant frequency, vertical gap separation distance, primary-to-secondary alignment, and other purposes such as safe operation and emergency power cutoff. This is also true for the case of a moving vehicle charging while moving, except that the single vehicle-mounted transmitter communicates with multiple independent transmitters in turn. This moving one-to-one relationship poses significant communication challenges.

[0057] The method of operation for charging a moving vehicle is to energize each independent transmitter 300 in the linear array to generate a resonant magnetic field in a sequential pattern as the vehicle receiver 320 passes each independent transmitter 300. The type of vehicle, its specific charging requirements, its speed, alignment with the transmitter 300, and its expected trajectory are all significant factors that make this problem difficult to solve.

[0058] As shown in Figure 9, this is certainly the case when an array of roadway-embedded transmitters 300 simultaneously experiences the presence of two or more vehicles 310, 312 and responds to the changing conditions of each vehicle 310, 312. In this case, communications between each vehicle 310, 312 and the specific ground transmitter 300 to which it is attached are discrete and distinctive so that other vehicles 310, 312 are not confused or receive and misinterpret data transmissions from nearby vehicles 310, 312. This requirement includes constraining the data communications system to the proximity of the target area of ​​the intended vehicle 310, 312. By comparison, other systems, such as radio broadcast and Wi-Fi, have ranges that are easily received by many nearby vehicles.

[0059] The first requirement is to have very close proximity transmitting and receiving capabilities limited to less than 2 meters. (A vehicle traveling at 60 MPH moves 88 feet per second. The time the receiver is exposed to the transmitter may be on the order of 0.02 seconds. In this time frame, the signal transmission time delays of 0.04 to 0.07 seconds typical of digital communication systems are clearly unacceptable.)

[0060] The second requirement is that the signals have no or very little time delay (or latency). This is necessary because the vehicles 310, 312 may be moving at high speed over the multiple transmitters 300, and individual communication between the on-board receiver 320 and any one transmitter 300 needs to be guaranteed.

[0061] A third requirement is that the communication system be able to "hand off" or sequence communications to the ordered array of transmitters 300. This can be done by wiring transmitters 300 together or by allowing one transmitter 300 to communicate to address the adjacent transmitter 300 in the ordered array using the near field communication system described herein.

[0062] The fourth requirement is full duplex operation or bidirectionality to ensure that during the very short period that the vehicles 310, 312 are present on the transmitter 300, data is exchanged in both directions, from the vehicle to the ground and from the ground to the vehicle.

[0063] A fifth requirement is uninterrupted communications under all weather and environmental conditions, which is achieved by using magnetic energy, as described herein, which allows communications through water, snow, ice, and other adverse road surface conditions.

[0064] A sixth requirement is to avoid the problems of multiple antennas located far from the vehicles 310, 312. Multiple distant antennas pose significant challenges due to road surface and vehicle body interference, such as multipath signal nulling. Reliable vehicle identification using multiple antennas is difficult to ensure while avoiding malicious hacking and other cyber-sabotage.

[0065] Those skilled in the art will appreciate that the communication system described herein provides a uniform solution to each of these requirements.

[0066] As described above, dynamic charging allows moving vehicles 310, 312 to be charged while in motion as they pass transmitters 300 on the roadway. Each transmitter 300 is energized in a controlled sequence as it anticipates the presence of a vehicle 310, 312 above it. Because the vehicle receiver 320 is only briefly "present" at any one charging station, a sequencing system is required that knows where the vehicle receiver and the charging station transmitter are relative to each other in real time. Ideally, a preemptive chaining procedure effectively establishes a traveling wave of magnetic energy traveling at the same speed as the vehicle receiver 320. To do this, a communication system with minimal latency, as described herein, is required. As described above, the communication system described herein is very fast (near-zero latency) and very close, so that the receiver 320 knows where it is relative to the transmitter 300. Therefore, to enable dynamic charging, a series of charging stations equipped with the communication system described herein is provided. During operation, each charging station and / or vehicle transmitter provides information including, for example, vehicle identification, power purchase billing, current and voltage regulation, resonant frequency, vertical gap separation distance, primary to secondary alignment, and other purposes such as safe operation and emergency power down, location, timing, trajectory, and / or speed information about the vehicle 310, 312 to the next transmitter so that when the vehicle's wireless charging receiver 320 is positioned over the transmitter 300 during movement, the next transmitter is activated.

[0067] Robust Hybrid Alternative Embodiment Wireless power transfer (WPT) systems of the type described herein also require a secure, unambiguous, point-to-point, low-latency, full-duplex link between the ground-side charging system and the vehicle-side charging electronics. The communication link must support battery management system (BMS) commands and other communication scenarios between the ground and vehicle electronics.

[0068] Supported operational scenarios include static and dynamic charging under a variety of weather conditions in domestic and international markets. The inductively coupled communication system (ICCS) is reliable in congested radio environments with both licensed and unlicensed co-channel users, while minimizing interference. This same inductive communication system is designed to function even when faced with water, snow, and ice.

[0069] In one embodiment, the narrowband full-duplex, low-latency, near-field data link for controlling the resonant inductive wireless power transfer system is augmented or replaced by a wideband full-duplex, low-latency, near-field data link between the ground assembly (GA) and the vehicle assembly (VA). This improved (hybrid or wideband) wireless duplex data link enables enhanced security, higher data rates, dynamic bandwidth selection, frequency agility, and modulation agility to address local spectrum regulations, electromagnetic field (EMF) safety, and data rate requirements for use in near-field inductive coupling communication systems.

[0070] To support the widest possible range of static deployment configurations, the data link must be able to withstand interference generated by adjacent or nearby ground-side assembly installations. Adjacent installations are attenuated either by distance (geographically or vertically in the case of parking lots) or by shielding structures (e.g., curbs or floors, as in parking lots). Adjacent systems may be located in the next vehicle's parking position or lane. In some adjacent cases, multiple clustered ground assemblies are deployed to a given vehicle in the same parking position or lane with corresponding clustered vehicle assemblies in a matching arrangement. Adjacent deployments are possible where a "macro" GA is composed of multiple smaller clustered GAs.

[0071] In a dynamic charging deployment configuration, for example, in a travel lane with a GA, the data link must not only tolerate interference generated by adjacent or nearby ground assembly installations, but also support smooth base station handover between successive ground assemblies or ground assembly clusters, in which the vehicle's charging platform sequentially supports multiple data links to successive ground assemblies as it moves through the travel lane with a GA.

[0072] Clustered Charger Scenario A modular coil design, where a single coil assembly can be deployed as a stand-alone ground assembly (GA) or two or more coil assemblies can be clustered to create a larger (geometric) ground assembly capable of higher power transfer, is advantageous for tailoring a WPT system to a user's needs. For example, for buses, trucks, trains, construction equipment, or other vehicles requiring wireless power transfer, the clustered ground assemblies and corresponding vehicle assemblies (VA) must be mounted adjacent to each other (e.g., a bus with a VA consisting of four adjacently mounted 50kW charging coils, each with its own dual inductive communication), to mitigate interference between one coil's communication signal and an adjacent coil's communication signal.

[0073] This deployment flexibility allows the vehicle to be fitted with one, two, or more vehicle assemblies, enabling higher power transfer than can be achieved with a single VA. Similarly, the ground assemblies (GAs) can be clustered and selectively enabled to match the geometry of the VA installation. In such clustered deployments, single GAs are installed closely adjacent to each other, forming a single macro-GA, and the inherent radiated power attenuation range limits impact the near-field data link's inherent advantage of not interfering with other nearby data links. In the near-field inductive communication link, the magnetic field strength and magnetic field power fall off as factors of 1 / (r3) and 1 / (r6), respectively, where r = radius.

[0074] The far-field radiated magnetic field from an antenna decays only as 1 / r for field strength and 1 / r2 for field energy, but the near-field magnetic field dominates at distances up to approximately λ / 2n. For example, the radiation resistance of the magnetic induction near-field transmission antenna at 13.56 MHz is very small compared to its reactive impedance (typically a ratio less than 0.0005) because most of the energy is coupled in the near field. Therefore, the far-field propagation energy of the magnetic signal is negligible compared to the energy of a comparable intentionally radiating system. This strong decrease in the magnetic field with distance means that while care is taken to process signals from adjacent coils of the same clustered coil assembly, there is no need to worry about interference between coils in adjacent vehicles or charging stations.

[0075] 10 illustrates an example of a clustered deployment in an exemplary embodiment, where the vehicle (e.g., bus) 1001 is equipped with clustered vehicle assemblies 1004 mounted on the bottom of the vehicle 1001. As shown, a passenger stop or parking bay 1003 is also equipped with a corresponding clustered deployment ground assembly 1002.

[0076] FIG. 11a illustrates the signaling and components used by the inductively coupled communication system (ICCS) 1101 of the wireless power transfer (WPT) system in an exemplary embodiment. FIG. 11a illustrates the ICCS 1101 in cross section, whereby the vehicle assembly (VA) 1102 and ground assembly (GA) 1103 are shown vertically opposed. Other deployment options are possible, such as horizontal mounting with the VA 1102 mounted on the side of a railcar and the GA 1103 mounted on a wall. GA-to-VA orientation in deployment is possible as long as close parallel opposition between the VA and GA is achievable. The VA 1102 communication components include at least a pair of receive antennas 1104 and 1106 arranged around a single transmit antenna 1105. The VA receive antennas 1104 and 1106 receive the transmissions 1110 and 1111 from the GA transmit antenna 1108. Similarly, the GA receive antennas 1107 and 1109 receive the transmitted signals 1112 and 1113. The bidirectional charging signal 1114 or 1127 can be present at any time during a communication session.

[0077] Additional near-field receiver antennas are deployed to aid in signal reception and improve upon the additional functionality provided by the full-duplex communication system.

[0078] FIG. 11b shows an exemplary electric vehicle 1115 as viewed from below. In one embodiment, additional receiver antennas are installed on or within the VA 1102. With at least two antennas on the x-axis (front to back) and at least two antennas on the y-axis (left to right), the VA 1102 is enabled to determine GA coil alignment displacements along both the x-axis and y-axis. Preferentially, these VA-mounted receiver antennas 1116, 1117, 1118, and 1119 are positioned at the four corners of the VA 1102, within range of the magnetically coupled GA transmitter 1108 signals 1112 and 1113. The VA coil assembly 1126 for transmitting and receiving the bidirectional charging signals 1114 and 1127 is also nominally present within the VA 1102 below the transmitting antenna 1105 of the VA 1102. The GA (not shown) structure replicates the communication antenna and charging coil assembly to mirror that of the VA1102, allowing dual communication and bidirectional charging.

[0079] Note that additional diversity receiver antennas can also be placed anywhere on the vehicle, preferentially displaced as much as possible along the length and width of the vehicle forming secondary distributed antenna / receiver systems 1121, 1122, 1224, and 1125. Depending on the range from the GA-implemented transmitter to the distributed antennas 1121, 1122, 1224, and 1125, the receive antennas can be either magnetic induction loops or near-field antennas as determined by the reactive near-field range and the radiated near-field (a.k.a. Fresnel region) range of the GA transmitter 1108 signals 1112 and 1113. In some embodiments, the displaced diversity receive antennas are magnetically coupled by either loop antennas mounted coplanar, parallel, or orthogonal (relative to the transmitter loop antenna) depending on their distance from the magnetic transmit antenna. The magnetic coupling link can also be extended when there is uncertainty about the range or coplanar mounting of the transmitter to the antenna using a hybrid loop antenna where one loop element is parallel to the transmitter loop and the second loop element is orthogonal.

[0080] For dynamic charging, distributed forward antennas or antennas 1121 and 1122 enable extended communication range and communication with GAs ahead of the current GA. This advanced communication enables GAs on the route before they are needed to minimize increases in vehicle start-up time. The distributed lateral antennas, right 1122 and 1124, and left 1121 and 1125, also provide centering along the direction of travel to maximize coil efficiency.

[0081] In one physical embodiment, four or more receiver antennas 1116, 1117, 1118, and 1119 are distributed forward and rearward (relative to the direction of travel) and laterally left and right on the VA 1102. Four additional antennas 1121, 1122, 1124, and 1125 are added, two mounted at the front 1120 (e.g., in the bumper, under the bumper, or on the vehicle frame) and two similarly mounted or embedded at the rear 1123. In both the front and rear placements, the antennas should be spaced as far apart as possible on the left and right sides on the horizontal axis.

[0082] The distributed antennas can be backhauled to the ICCS 1101 using wired or wireless (Bluetooth, Zigbee (IEEE 802.15), etc.) connections. The ICCS 1101 compensates for the various reception and processing times required for the communication link method and data protocol used.

[0083] The distributed antennas 1121, 1122, 1124, and 1125 with a common or known offset relative to the horizontal plane also enable improved positioning capabilities. The use of diversity receivers enables positioning and ranging techniques such as signal strength measurement (SSM), time of arrival (TOA), and time difference of arrival (TDOA). The use of directional receiver antennas enables angle of arrival (AoA) techniques. The front-mounted directional antenna with AoA techniques is particularly advantageous for forward positioning and alignment.

[0084] The permanent 79 GHz band allocation for Intelligent Transportation Systems (ITS) facilitates the use of TOA, TDOA, AOA, or hybrid positioning using two or more of the techniques described. The 12 ITU (International Telecommunication Union)-defined Industrial, Scientific, and Medical (ISM) bands are another potential spectrum that can be used for positioning (six are available globally, and the other six ISM bands may be available depending on local regulations). Positioning accuracy varies with the use of higher frequencies, which provide higher resolution, and lower frequencies, which provide lower resolution.

[0085] The use of the distributed antennas with the TDOA, AOA, or TDOA-AOA hybrid positioning techniques can be used to generate the Z axis (vertical) measurement. In some embodiments, non-wireless means, such as an ultrasonic transducer range finder, can be used for Z axis estimation.

[0086] Alternatively, if the vehicle is not properly equipped, the make, model, manufacturer, and random variable nominal Z-gap can be uploaded from the vehicle or a ground network server to set the wireless power transfer GA voltage and coil enablement within the coil cluster.

[0087] Software Defined Radio One option for implementing the improved ICCS1101 is to use software-defined transmitters and receivers to improve the signal between the ground station and vehicle installation using the inductive coupling communication between the Ground Assembly (GA) 1103 and the Vehicle Assembly (VA) 1102.

[0088] The ICCS 1101, in sample embodiments, is designed to provide a choice of two or more types of circuitry for amplitude modulation, phase modulation, and frequency modulation, and circuitry that enables the use of spreading techniques such as direct spread spectrum and chirp spread spectrum (CSS) (e.g., binary quadrature modulation (BOK), frequency hopping, and direct modulation (DM) as desired). As described below, such functionality may be implemented in a field programmable gate array (FPGA) in sample embodiments, but the described functionality may also be deployed using separate integrated circuit components and / or multi-chip modules and / or in software executed by other processing devices such as digital signal processors (DSPs). In some embodiments, the ICCS 1101 may use multiple simultaneous subcarriers, such as orthogonal frequency division multiplexing (OFDM), where the subcarriers are allocated in unlicensed spectrum (or reserved spectrum) and may use any of the described modulation schemes.

[0089] FIG. 12a illustrates the functional elements of the ICCS in a sample embodiment. As shown, receiver 1201 uses one or more antennas specialized for magnetic induction signals. The received analog signal is filtered in receiver 1201 as described above. The received signal is processed by digitization element 1202, which obtains the received analog signal and converts it into a digital representation of the signal. The digital representation of the received signal is then digitally processed by processing element 1203. Data extracted from the processed signal is then output via digital interface 1206.

[0090] Received digital data is also applied to the processing element 1203 via an input interface 1207. The received data is packaged by the processing element 1203 before being converted to an analog signal in the analog conversion element 1204. Once converted to analog form, it is then filtered and transmitted by a transmitter 1205 via one or more antennas dedicated to magnetic induction signals.

[0091] In a sample embodiment, the ICCS functional elements of Figure 12a are implemented in any of several ways. For example, the ICCS can be configured as follows: Circuits consisting of independent integrated circuits (ICs) (e.g., analog-to-digital converters (ADCs), digital-to-analog converters (DACs)) with programmable elements (e.g., field programmable gate arrays (FPGAs), EEEPROMs, etc.) As a mixture of hardware (ICs), software, and embedded firmware in a multi-chip module. As firmware residing on an Application Specific Integrated Circuit (ASIC) that contains the necessary control logic, digitization, and analog conversion functions. As a software construct running on a computer platform (such as a central processing unit (CPU) or digital signal processor (DSP)) with accompanying digital-to-analog and analog-to-digital circuitry.

[0092] In either case, analog signal filtering can be included in the chosen design if desired (e.g., in the case of a superheterodyne design with a bandpass intermediate frequency (IF) stage or a direct conversion design with limited analog bandwidth).

[0093] The choice of ICCS implementation (FPGA and DSP) and deployment (as a separate IC, multi-chip IC module, or ASIC assembly) largely depends on development costs, production volume, and the cost of required computer resources. In implementation, the FPGA provides parallel-path signal processing, while the CPU / DSP provides superior memory access and operating system functionality to simplify the task. The separate IC package offers the most flexibility in component selection and component placement, while the multi-chip module provides fixed interconnects between discrete components. The ASIC package provides both ICCS components and interconnects in a single integrated subsystem, maximizing development time and cost but providing the easiest deployment. In a sample embodiment, the ICCS configuration is selected at the time of manufacture, but can also be user-selected during use.

[0094] FIG. 12b shows a sample embodiment of the ICCS 1101 including the VA 1202 and GA 1201 in a separate integrated circuit embodiment. As shown, the communication channels 1211 and 1227 use magnetic induction to couple a short-range, minimally propagating magnetic field for the low-power magnetic link between the GA 1202 and the VA 1202. The GA communication signals 1211 and the VA communication signals 1227 are either narrowband or wideband depending on the preset programming, the stage of the charging cycle (approach, coarse positioning, fine positioning, foreign object detection (FOD) and organism detection (LOD) scan, charging, end of charge, or whether a signal quality threshold (e.g., received signal strength, bit error rate) has been exceeded.

[0095] The core 1262 of the GA inductively coupled communication system 1260 includes a field programmable gate array (FPGA) 1265, a digital-to-analog converter (ADC) 1263, and a digital-to-analog converter (DAC) 1264. The FPGA 1265 provides computational resources. Computational operations performed by the FPGA 1265 include signal processing (signal summing, combining, selection, modulation, demodulation, digital filtering, data extraction, automatic gain control (AGC), ICCS hardware control, etc.). Data from the GA and external systems is input to the GA core 1262 via a digital interface 1240 for processing for transmission to the VA 1261.

[0096] The GA core digital-to-analog converter (DAC) 1264 functions to convert the FPGA's digital output bitstream into a quantized analog signal which is then amplified by the transmit amplifier 1208, then band-limited and smoothed by the band-pass filter 1209, and transmitted by the GA transmit antenna 1210 where it propagates as the induced magnetic signal 1211.

[0097] The GA communication signal 1211 passes through the air gap 1266 between the VA 1261 and GA 1260 and is received by the VA receiver antennas 1212 and 1213 (in this example, two receiver antennas are used, but the design supports the use of one receiver antenna and any number of receiver antennas). Upon reception by one or more of the VA pair's coupled antenna structures 1212 and 1213, the GA signal is bandpass filtered using filters 1214 and 1215. The bandlimited signal is then amplified by the pair of low-noise amplifiers (LNAs) 1216 and 1217, one per VA receiver path. A second pair of bandpass filters 1218 and 1219 is then used to limit the signal frequency bandwidth for direct-to-digital conversion in each of the VA receive paths.

[0098] The analog-to-digital conversion is performed by the VA ADC 1223, which can be implemented as a paired set of ADCs or as an n-channel ADC (depending on the number of receive antennas used). The digitized signal is then passed to the VA FPGA 1222, which converts the received digitized signal using conventional digital signal processing techniques, processes the reconstructed bit stream (e.g., framing, removing training sequences, implementing forward error correction and data encoding (e.g., convolutional coding, turbo coding, Hamming code), and decoding security-masked bit sequences), and delivers the bit stream via digital interface 1238 to a vehicle battery management system (VBMS) 1239, potentially via an intermediate processor, network, and protocol such as a controller area network (CAN bus) (not shown). Measurements related to the communication signal are output over digital interface 1236 to a processor 1250 implemented in the vehicle. Measurements related to the charging signal are output over digital interface 1237.

[0099] The vehicle battery management system (VBMS) 1239, the vehicle occupant information system, the vehicle entertainment system, and other onboard data or telemetry systems provide bit streams to the VA FPGA 1222 via the digital interfaces 1238 and 1243 according to the configuration of the VBMS and onboard systems. The VA FPGA 1222 applies the framing and training sequences, implements forward error correction and data encoding (e.g., using convolutional coding, Hamming codes, or Hadamard codes), encodes a security-masked bit sequence, and delivers the bit stream to the VA digital-to-analog converter (DAC) 1221. The output of the VA DAC 1221 is then amplified by a transmit amplifier 1224. The VA signal for transmission is then filtered by a bandpass filter 1225 to match the desired channel bandwidth. The band-limited analog VA signal is then transmitted using a coupled antenna structure 1226 via the magnetic-air interface 1266.

[0100] The VA induced magnetic signal 1227 is received by one or more of the GA coupled antenna structures 1228 and 1229. The VA signal is then bandpass filtered on each GA receive path using filters 1230 and 1231. The bandlimited signal is then amplified by the pair of low noise amplifiers (LNAs) 1232 and 1233, one for each GA receive path. A second pair of bandpass receivers 1234 and 1235 is then used to limit the signal frequency band for direct digital conversion on each of the GA receive paths. In some configurations of the ICCS, the bandpass filters 1290, 1214, 1215, 1218, 1219, 1225, 1230, 1231, 1234, and 1235 are implemented as a switched filter bank to accommodate multiple frequency bands.

[0101] The analog-to-digital conversion is performed by the GA ADC 1263, which can be implemented as either a pair of ADCs or a two-channel ADC. The digitized signal is then passed to the VA FPGA 1265. The VA FPGA 1265 converts the received digitized signal using conventional digital signal processing techniques, then processes the reconstructed bit stream (e.g., framing, removing training sequences, implementing forward error correction and data encoding (e.g., using convolutional coding, turbo coding, or Hamming code), and decoding security-masked bit sequences), and delivers the bit stream to the ground-side computational resources 1241 local to the wireless charger and external communication interface 1242, potentially via intermediate processors, interfaces, and protocols (not shown). In the event of a detected (by the GA) or signaled (by the VA) fault event, the VA FPGA 1265 signals the emergency shutdown 1244 (e.g., in the event of a coil fault or thermal threshold being exceeded) and disables the charging signal 1245.

[0102] Closed and open loop control and reporting The ICCS 1101 actively measures both the charging signal 1245 and communication signals 1211 and 1227. Measurements include received signal strength, bit error rate, sum and difference of the signal 1227 received by the first 1228 and second 1229 antenna structures, Eb / N0 (the ratio of energy per bit (Eb) to the spectral noise density (N0)), received signal strength indication (RSSI), center frequency, and amplitude and phase shift at the first and second receive antennas 1228 and 1229. The measurements are delivered via the GA digital control interface 1241 to the ground or, in the case of one or more vehicle-implemented processors 1250 for alignment detection, and management and control of a closed-loop charging system, via the VA digital control interface 1236.

[0103] The closed loop control may include providing near real-time voltage and current measurements (of VAs) to the FPGA 1222, VA thermal measurements, Z-gap changes due to loading or unloading of the vehicle, soft VA or GA fault (clustering) alerts, alerts of operational events during charging, and communication to the GA and VA as needed of additional vehicle side sensing related to the VA or vehicle electrical system as needed.

[0104] The VBMS 1239 uses the VA control digital interface 1238 to pass commands to be sent to the charging system which can instruct the GA via the GA control digital interface 1241 .

[0105] Spread Spectrum Wideband Signal In one embodiment, the wideband signal used in the full-duplex VA-GA communication link is an asynchronous direct-sequence spread-spectrum signal using complementary code sequences. In some deployment scenarios, for example, when GAs are deployed adjacently as components of a larger macro GA cluster (e.g., as a single vehicle parking stall charger), distance cannot be relied upon to provide sufficient magnetic signal attenuation to mitigate co-channel interference between the multiple GA-VA and VA-GA communications. The use of the spreading sequence technique allows each of the GA and VA receivers to distinguish between signals transmitted to each receiver and co-channel interference. The use of the complementary codes in a direct-sequence spread-spectrum system is used to enable correlation processing by the receivers to overcome the co-channel interference and lack of synchronization between the GA and VA transmitters.

[0106] If the distance between the GAs (and paired VAs) is sufficient, signal attenuation of the magnetic signal allows code reuse, allowing for shortened code sequences, which minimizes the number of "chips" per bit in the direct sequence spread spectrum system, thereby increasing the data rate for the same bandwidth.

[0107] In communication systems that use inductive coupling for transmission, signal reflections and multipath are minimized by the inherent physics of magnetic field propagation. In one embodiment, direct sequence code spreading using complementary code sequences is designed to mitigate co-channel interference between closely spaced (clustered, adjacent, or proximate) transmitters and receivers, such as in a wireless charging parking lot or traffic lane.

[0108] An asynchronous system allows multiple separate ground assemblies, each with its own transmitter and receiver, to be deployed adjacent or in close proximity without the need for a shared real-time timing source. The lack of a common timing source eliminates the need for clock recovery or phase locking between the GA and VA systems. Therefore, each aligned GA-VA pair can communicate independently, regardless of the number of deployed or functioning units. If a GA is not paired with a VA (due to different deployment alignments or VA fault conditions), the GA will not initiate a charging signal.

[0109] In a sample embodiment, such a charging system can be used to charge a vehicle by positioning the VA of the vehicle relative to the GA to receive a charging signal. The coils of the GA and VA are selectively enabled based on the geometrical orientation of the VA relative to the GA for charging, such that only the aligned coils are activated. If desired, one or both of the transceiver systems of the GA and VA are selected to have the same type of signal processing circuitry. The transceiver systems can then be used to communicate charging management and control data between the transceiver systems of the GA and VA via an inductive link during charging.

[0110] As described above, the transceiver system may include hardware, software, and / or firmware that provides one or more of amplitude modulation, phase modulation, frequency modulation, orthogonal frequency division multiplexing (OFDM), and spread spectrum implementing techniques including at least one of direct sequence spread spectrum, chirp spread spectrum (CSS), binary orthogonal modulation (BOK), frequency hopping, and direct modulation (DM). The types of transceiver systems are selected to be identical, for example, at the time of design / manufacturing or by user selection. The VA and GA can then communicate software updates, diagnostic or telemetry information, and / or passenger entertainment service data between them while charging.

[0111] FIG. 13a shows an overhead view of wireless charging stations implemented in a parking lot arranged in a single-row geographical configuration 1301 in a sample embodiment. The parking stalls 1304, 1305, 1306, and 1307 are conventionally defined by curb 1303 and painted line markers. A travel lane 1302 provides vehicle access to each parking stall. In this example, each parking stall 1304, 1305, 1306, and 1307 is fitted with a wireless charging ground assembly (GA) 1310, 1311, 1312, and 1313. While the GAs 1310, 1311, 1312, and 1313 are shown as a clustered assembly of four adjacent, independent GAs, other shapes for the length and width of the parking stalls are possible.

[0112] The operational GAs 1311, 1312, and 1313 radiate magnetic communication signals 1315 before and during each charging period. Due to the propagation characteristics of the coupled magnetic induction signals and the vertical antenna orientation, co-channel interference is potentially limited within the GA cluster and potentially between adjacent parking stalls 1314.

[0113] The magnetic signals emitted by each operational GA cluster 1311, 1312, and 1313 are one source of co-channel interference for their respective (in this example, there are up to eight signals per cluster: four from GA to VA and four from VA to GA) communication links. While potential overlap or collision of magnetic signals 1315 from neighboring operational GAs 1312 or 1313 with parking stalls is also possible, providing sufficient physical separation 1309 between non-adjacent operational GAs 1311 and 1312 helps significantly reduce or eliminate potential co-channel interference. Additional chargers that may cross the travel lane 1302 will have sufficient physical separation 1308 to limit the possibility of co-channel interference.

[0114] FIG. 13b shows an overhead view of a wireless charging station implemented in a parking lot deployed in a two-row geographical arrangement 1316 in a sample embodiment. The two rows 1316 of parking lots with GAs are separated by a travel lane 1304. In this illustration, parking stalls 1317, 1320, 1321, and 1322 currently have operational GAs, while parking stalls 1318, 1319, 1323, and 1324 are inoperable (i.e., in a non-charging state, the parking stalls are vacant or occupied, but charging may not be functioning, have finished, or has not yet started). Potential co-channel interference in the magnetically coupled full-duplex communication system exists in the operational parking stalls (those radiating magnetic signals 1315). Co-channel interference between the clusters of GAs within a macro GA (where the macro GA consists of four adjacent GAs, each with independent duplex communication) and potential co-channel interference between adjacent macro GAs 1314 are tolerated by the communication system. The closest operable GAs 1317 and 1320 in the same row, or the closest operable GAs 1322 and 1320 across rows with sufficient geographic separation 1309, do not have potential interference, as do GAs 1308 that may be geographically separated across the one or more travel lanes 1304 that provide access to the two rows of charging stations 1316.

[0115] Active communication links In one embodiment, the full-duplex link is always active during the charging cycle, providing continuous communication between the VA and GA, as well as secure transmission for vehicle software updates, diagnostics, telemetry, entertainment, and other information. The ICCS1101 supports transmit and receive frequency changes, modulation, and coding to support specific events before, during, and after the charging period.

[0116] In a clustered deployment, each GA may support independent communication links with each VA. In this way, a clustered GA can support a single VA or clustered VAs (e.g., two VAs in a row, two VAs in two rows, two VAs in three rows, etc., up to the maximum width and length of the vehicle), or even partially operational VAs by simply activating a charging signal for a GA with a geometrically corresponding VA. Because a single charging site may support multiple vehicle configurations, using independent communications facilitates both deployment and operation. Alternatively, the GAs can be deployed as a cooperative cluster in which a single GA and VAs maintain communication when the charging signal is activated.

[0117] Static Case The dual communication data link helps provide authentication and access control for the WPT in static and dynamic charging scenarios. Additionally, the data link can be used to provide information, software updates, diagnostic or telemetry information, and passenger entertainment services between the GA and VA. The dual data link's unique characteristics enable faster control system feedback, such as deactivating the charging signal after detecting a foreign object introduced between the GA and VA. Placing the communication system receiver in the physical vicinity of the charging coil also allows for early detection of an introduced obstruction.

[0118] Dynamic Case In the dynamic charging embodiment, a communication link is maintained as the vehicle travels down an equipped railroad or highway. In this deployment, the ICCS, enabled with a direct sequence spread spectrum (DSSS), is used to select code sequences that are as short and orthogonal as possible to adjacent GAs, allowing for fast soft handoff between GAs. The magnetic induction communication link can be used to upload the expected GA sequence and associated code sequence to the vehicle, increasing the allowable speed of the GA-equipped travel lane or railroad. The uploaded sequence can be used to preload the ICCS to demodulate and decode the communication signal faster.

[0119] Figure 14 shows an example of a highway 1401 with dynamic charging enabled. The highway is set between two curbs 1402 and 1403 and is divided into a travel lane 1405 and a charging lane 1406. These charging lanes can be configured for speed and vehicle gap length to better optimize charging. The charging lane speed is configured to manage the charging time (also known as dwell time) for each set of GAs 1407. Vehicles 1404 and 1409 can move into the charging lane, here showing clear lane markings or physical separation 1408, either freely or with designated entry points.

[0120] In the railroad example, a series or array (series of clusters) of GAs are placed between the tracks (up to one gauge wide) to charge VA-equipped railcars, and the GAs may face VAs placed on the side or top of the railcars.

[0121] By sequencing multiple GAs along the driving route, customizations of said GAs, such as antenna extensions (for both charging and communication), can be deployed to provide autonomous vehicle control information for optimal charging both in the current lane and at potential charging stations along the potential lane.

[0122] Independent communication paths for each assembly In one embodiment, a full-duplex inductively coupled data link is deployed to each element of a cluster of independent GAs (macro GAs). Similarly, each independent VA (part of a macro VA cluster) is equipped with a full-duplex inductively coupled data link.

[0123] This independent operation of data links minimizes communication latency by removing the circuitry and processing required to coordinate communication between assemblies when they are clustered. The lack of coordination also means that initiation of said links is fast, as it enables simultaneous data link setup by each assembly pair (GA to VA).

[0124] The independent data links facilitate deployment of single and multiple assemblies. Geometrically arbitrary clusters of GAs can be deployed in any area or pattern required to support vehicle dimensions and expand power needs.

[0125] Economies of scale can be achieved by making each VA and GA functionally identical (e.g., using the same magnetic induction antenna and a common resonant induction coil unit), which also helps to increase the efficiency of the charging signal and the overall power efficiency of the ICCS.

[0126] The independent nature of the GA and VA pairing means that failure of a single GA or VA in a clustered deployment results in a graceful degradation to a lower state of charge through the remaining GA and VA pair. In one aspect, the failure of a VA unit results in the immediate interruption of the charging signal from the pair of GAs. Because this GA is no longer radiating, the vehicle is no longer subject to heating from the no longer terminated charging signal.

[0127] Those skilled in the art will appreciate that the topology and circuit implementation methodology described herein allow for effective implementation as a single application-specific integrated circuit, a separate integrated circuit, a multi-chip module, and / or as software running on a digital signal processing circuit with auxiliary A / D and D / A circuitry. Furthermore, while the disclosure contained herein relates to providing power to a vehicle, it should be understood that this is only one of many possible applications, and other embodiments, including non-vehicle applications, are possible. For example, those skilled in the art will appreciate that there are many applications for providing a full-duplex data link in non-vehicle inductive charging applications, such as portable consumer electronics chargers, such as those used to charge toothbrushes (e.g., Powermat™), cell phones, and other devices. Furthermore, those skilled in the art will appreciate that the transmission bandwidth (data rate) of the communication systems described herein can be increased using simultaneous amplitude and angle modulation using other complex modulation methods, and by using multiple modulated transmit and return path carriers. Accordingly, these and other such applications are within the scope of the following claims.

Claims

1. A vehicle charging system, comprising: at least two clustered ground assemblies, each having one or more coils, each having a full duplex inductive coupling data communication system having a first transmit / receive system for transmitting a first signal via a first inductive link and receiving a second signal via a second inductive link; a vehicle assembly having one or more coils, the vehicle assembly including a full duplex inductive coupling data communication system having a second transmission / reception system for receiving the first signal via the first inductive link and transmitting the second signal via the second inductive link; a processor that communicates charging management and control data between the first and second transceiver systems via the first and second inductive links during charging for at least one of alignment detection or closed-loop charging system management and control; and coils of the clustered ground assemblies are selectively enabled and arranged in parallel with one or more selectively enabled coils of the vehicle assembly during charging, whereby the one or more selectively enabled coils of the vehicle assembly receive charging signals from one or more corresponding selectively enabled coils of the clustered ground assemblies that are geometrically matched to the vehicle assembly during charging; Vehicle charging system.

2. 2. The vehicle charging system of claim 1, wherein the processor disables the charging signal if a fault event is detected by or received from the clustered ground assemblies.

3. 10. The vehicle charging system of claim 1, wherein the processor provides measurements to the vehicle assembly including signal strength, bit error rate, sum and difference of first or second signals received by the first and second antenna structures of the vehicle assembly and one or more of the clustered ground assemblies, respectively, energy per bit to spectrum noise density ratio, received signal strength indication, center frequency, and at least one of amplitude and phase shift at the first and second antenna structures of the vehicle assembly and the one or more of the clustered ground assemblies.

4. 10. The vehicle charging system of claim 1, wherein the processor provides to at least one of the clustered ground assemblies or the vehicle assemblies near real-time voltage and current measurements of the vehicle assembly, thermal measurements of the vehicle assembly, Z-gap changes due to loading or unloading of the vehicle, vehicle assembly or ground assembly fault alerts, alerts regarding operating events during charging, and additional vehicle detection data related to the vehicle assembly or vehicle electrical system.

5. 10. The vehicle charging system of claim 1, wherein at least one of the clustered ground assemblies and the vehicle assembly communicate at least one of software updates, diagnostic or telemetry information, and passenger entertainment service data between the at least one of the clustered ground assemblies and the vehicle assembly via the first and second inductive links during charging.

6. 2. The vehicle charging system of claim 1, wherein the first transceiver system processes at least one of commands or data from the vehicle assembly and an external system for transmission to at least one of the clustered ground assemblies, and processes data received from the at least one of the clustered ground assemblies for distribution to the vehicle assembly and at least one of the external system.

7. 2. The vehicle charging system of claim 1, wherein the first signal and the second signal are configured as either narrowband signals or wideband signals depending on the stage of the charging cycle or whether a predetermined threshold of signal quality has been exceeded.

8. 2. The vehicle charging system according to claim 1, wherein the first signal and the second signal are configured as asynchronous spread spectrum signals using complementary code sequences.

9. 9. The vehicle charging system of claim 8, wherein the first and second transmitting / receiving systems each include a direct sequence spread spectrum system that transmits a code sequence that enables the first and second transmitting / receiving systems to distinguish between signals and co-channel interference.

10. 10. The vehicle charging system of claim 9, wherein the code sequence is a complementary code sequence.

11. 2. The vehicle charging system according to claim 1, further comprising: a cluster of ground assemblies, each ground assembly having one or more clusters of coils, each coil having a full duplex inductive coupling data communication system including a first transmit / receive system for transmitting a first signal via a first inductive link and receiving a second signal via a second inductive link; A vehicle charging system wherein each ground assembly communicates independently from each other ground assembly.

12. 2. The vehicle charging system according to claim 1, further comprising: a cluster of at least two vehicle assemblies, each vehicle assembly having a digital interface and one or more coils, each vehicle assembly having a full duplex inductive coupling data communication system including a second transceiver system for receiving a first signal via a first inductive link and transmitting a second signal via a second inductive link; A vehicle charging system in which each vehicle assembly communicates independently from each other vehicle assembly.

13. 1. A method of charging a vehicle, comprising: positioning vehicle assemblies of a vehicle relative to two or more clustered ground assemblies to receive charging signals, the vehicle assemblies having one or more coils, the vehicle assemblies having a full duplex inductive coupled data communication system having a first transmit / receive system that receives a first signal via a first inductive link and transmits a second signal via a second inductive link, and each ground assembly having one or more coils, the vehicle assemblies having a full duplex inductive coupled data communication system having a second transmit / receive system that transmits a first signal via the first inductive link and receives a second signal via the second inductive link; the placing step; selectively enabling coils of the clustered ground assemblies and the vehicle assemblies; communicating charging management and control data between the first and second transceiver systems via the first and second inductive links during charging for at least one of alignment detection or closed-loop charging system management and control; disposing the selectively enabled coils of the vehicle assembly in parallel with one or more selectively enabled coils of the clustered ground assemblies to receive the charging signal from one or more corresponding selectively enabled coils of the clustered ground assemblies that are geometrically matched to the vehicle assembly during charging; A method comprising:

14. 14. The method of claim 13, wherein the charging signal is disabled if a fault event is detected by or received from one of the clustered ground assemblies by the ground assembly.

15. 14. The method of claim 13, further comprising: providing measurements to the vehicle assembly including at least one of signal strength, bit error rate, sum and difference of first or second signals received by the vehicle assembly and first and second antenna structures of one or more of the clustered ground assemblies, respectively, energy per bit to spectral noise density ratio, received signal strength indication, center frequency, amplitude and phase shift at the vehicle assembly and the first and second antenna structures of the one or more of the clustered ground assemblies.

16. 14. The method of claim 13, further comprising: and communicating near real-time voltage and current measurements of the vehicle assembly, thermal measurements of the vehicle assembly, changes in Z-gap due to loading or unloading of the vehicle assembly, fault alerts of the ground assembly or vehicle assembly, alerts regarding mid-charge operating events, and additional vehicle detection data related to the vehicle electrical system between the vehicle assembly or the clustered ground assembly and the vehicle assembly.

17. 14. The method of claim 13, further comprising: communicating at least one of software updates, diagnostic or telemetry information, or passenger entertainment services data between at least one of the clustered ground assemblies and the vehicle assembly via the first and second inductive links during charging.

18. 14. The method of claim 13, further comprising: a first transmitting / receiving system processing step of processing and transmitting at least one of commands or data from the vehicle assemblies and external systems to at least one of the clustered ground assemblies, and processing and distributing data received from at least one of the clustered ground assemblies to at least one of the vehicle assemblies and external systems.

19. 14. The method of claim 13, further comprising: configuring the first and second signals as narrowband or wideband signals depending on a stage of a charging cycle or whether a signal quality threshold has been exceeded.

20. 14. The method of claim 13, further comprising: The method comprising configuring the first signal and the second signal as asynchronous spread spectrum signals.

21. 21. The method of claim 20, wherein the first and second transmitting and receiving systems each comprise a direct sequence spread spectrum system, and further comprising:

20. A method comprising the step of: broadcasting a code sequence that enables the first and second transmitting / receiving systems to distinguish between signals and co-channel interference.

22. 22. The method of claim 21, wherein the code sequences are complementary code sequences.

23. 14. The method of claim 13, wherein each ground assembly communicates independently from each other ground assembly.

24. 14. The method of claim 13, further comprising:

1. A vehicle charging system comprising a cluster of at least two vehicle assemblies, each vehicle assembly having a digital interface and one or more coils, each vehicle assembly having a full-duplex inductively coupled data communication system including a second transceiver system for receiving a first signal via a first inductive link and transmitting a second signal via a second inductive link, each vehicle assembly communicating independently from each other vehicle assembly.

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