Alignment device and method for aligning a transmitter and a receiver in a wireless power transfer system - Patents.com

Abstract

The alignment device comprises a coil configured to generate an induced voltage from a magnetic field or an electrode configured to generate an induced voltage from a magnetic field, and further comprises a comparator configured to compare the induced voltage to a threshold voltage and activate an indicator based on the comparison.

Description

[Technical field]

[0001] The present disclosure relates generally to wireless power transfer, and more particularly to an alignment device and method for aligning a transmitter and receiver in a wireless power transfer system. [Background technology]

[0002] Wireless charging and wireless power transfer systems are becoming an increasingly important technology in enabling the next generation of devices. The potential benefits and advantages offered by this technology are evident in the growing number of manufacturers and companies investing in this technology.

[0003] Various wireless power transfer systems are known. A typical wireless power transfer system includes a power source electrically connected to a wireless power transmitter, and a wireless power receiver electrically connected to a load.

[0004] In magnetic induction systems, a transmitter has a coil with a fixed inductance that transfers electrical energy from a power source to a receiving coil with a fixed inductance. Power transfer occurs through magnetic field coupling between the transmitter inductor and the receiver inductor. These magnetic induction systems have a limited range and the transmitter inductor and receiver inductor must be tightly coupled, i.e., the coupling factor must be greater than 0.5 and in optimal alignment for efficient power transfer.

[0005] There are also resonant magnetic systems where power is transferred by magnetic field coupling between the transmitter inductor and the receiver inductor. The transmitter and receiver inductors are loosely coupled, i.e., the coupling factor is less than 0.5. In resonant magnetic systems, the inductor is resonated using at least one capacitor. In resonant magnetic systems, the transmitter is self-resonant and the receiver is self-resonant. The range of power transfer in resonant magnetic systems is increased over that of magnetic induction systems, and alignment problems are corrected. Electromagnetic energy is produced in magnetic induction and resonant magnetic systems, but the majority of the power transfer is through magnetic fields. Very little, if any, power is transferred electrocapacitively or resonant electrocapacitively (electric fields).

[0006] The Qi wireless charging standard is an exemplary implementation of a magnetic induction system. The Qi wireless charging standard is used in low-power consumer electronics such as smartphones and wearable devices. Furthermore, low-cost power converters, coils, and integrated circuits are available for use in the Qi wireless charging standard. The Qi wireless charging standard operates in the kHz frequency range. Thus, devices operating according to the Qi wireless charging standard have a limited coupling range, require precise coil alignment, and use ferrite-based coils, which can be heavy and fragile. As a result, the range of application of the Qi wireless charging standard is limited.

[0007] In electrocapacitive systems, the transmitter and receiver have capacitive electrodes. Power transfer is achieved by coupling of electric fields between the capacitive electrodes of the transmitter and the capacitive electrodes of the receiver. Similar to resonant magnetic systems, there are resonant electric systems in which the capacitive electrodes of the transmitter and the capacitive electrodes of the receiver are resonated using at least one inductor. In resonant electric systems, the transmitter is self-resonant and the receiver is self-resonant. Resonant electric systems increase the range of power transfer compared to that of electrocapacitive systems and correct alignment problems. Although electromagnetic energy is produced in electrocapacitive and resonant electric systems, the majority of the power transfer is through electric fields. Very little, if any, power is transferred by magnetic induction or resonant magnetic induction. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent Application Serial No. 17 / 018,328 [Patent Document 2] U.S. Patent No. 10,424,942 Summary of the Invention [Problem to be solved by the invention]

[0009] Although techniques for wireless power transfer are known, improvements are desirable. [Means for solving the problem]

[0010] It should be appreciated that this Summary is provided to introduce a selection of concepts in a simplified form that are further described in the Detailed Description. This Summary is not intended to be used to limit the scope of the claimed subject matter.

[0011] Thus, in one aspect, an alignment device is provided comprising a coil configured to generate an induced voltage from a magnetic field, or an electrode configured to generate an induced voltage from an electric field, and a comparator configured to compare the induced voltage with a threshold voltage and activate an indicator based on the comparison.

[0012] In one or more embodiments, the induced voltage is proportional to the strength of the magnetic field across the coil or the electric field across the electrodes.

[0013] In one or more embodiments, the alignment device is configured to align the transmitter and receiver for optimal power transfer efficiency.

[0014] In one or more embodiments, the alignment device is configured to align the transmitter coil and the receiver coil for optimal power transfer efficiency.

[0015] In one or more embodiments, the alignment device is configured for use with a high frequency wireless power transfer system.

[0016] In one or more embodiments, the coil or electrodes form part of a field detection unit (FDU).

[0017] In one or more embodiments, the FDU includes at least one tuning capacitor configured to tune the coil.

[0018] In one or more embodiments, the FDU includes a rectifier configured to rectify the induced voltage from alternating current (AC) to direct current (dDC).

[0019] In one or more embodiments, the FDU includes at least one diode configured to add a capacitance to the coil to reduce the resonant frequency of the coil.

[0020] In one or more embodiments, the alignment device includes multiple FDUs, each including an individual coil configured to generate an induced voltage from a magnetic field or an individual electrode configured to generate an induced voltage from an electric field.

[0021] In one or more embodiments, the alignment device comprises four FDUs positioned orthogonally to one another in a plane.

[0022] In one or more embodiments, the FDUs are positioned equidistant from one another in the plane.

[0023] In one or more embodiments, the alignment device comprises five FDUs positioned orthogonally to one another in a plane.

[0024] In one or more embodiments, the four FDUs are positioned equidistant to a central FDU in the plane.

[0025] In one or more embodiments, each FDU is associated with an individual indicator.

[0026] In one or more embodiments, the comparator forms part of the main board.

[0027] In one or more embodiments, the main board further comprises an indicator.

[0028] In one or more embodiments, the main board further comprises a voltage divider configured to scale down the voltage.

[0029] In one or more embodiments, the main board further comprises a sensitivity control configured to control the threshold voltage.

[0030] In one or more embodiments, the alignment device further comprises a spirit level.

[0031] According to another embodiment, an alignment device is provided for determining an optimal alignment of a transmitter and a receiver configured to derive power from the transmitter by magnetic or electric field coupling.

[0032] In one or more embodiments, the alignment device includes a coil configured to generate an induced voltage from a magnetic field.

[0033] In one or more embodiments, the alignment device comprises electrodes configured to generate an induced voltage from an electric field.

[0034] In one or more embodiments, the alignment device comprises an indicator configured to be activated based on a comparison between the induced voltage and a threshold voltage.

[0035] In one or more embodiments, the alignment device further comprises a comparator configured to compare the induced voltage with a threshold voltage.

[0036] In one or more embodiments, the alignment device comprises any of the features or elements of the alignment devices described.

[0037] According to another aspect, a method is provided, the method comprising: a) activating a transmitter positioned on one side of the material; b) positioning an alignment device on the other side of the material opposite the transmitter; c) generating an induced voltage from a magnetic field generated by the transmitter via a coil of the alignment device or from an electric field generated by the transmitter via an electrode of the alignment device; d) activating an indicator of the alignment device based on a comparison of the induced voltage to a threshold voltage; e) repositioning the alignment device relative to the transmitter; f) repeating steps c) to e) until an optimal power transfer efficiency between the transmitter and the alignment device is obtained. Includes.

[0038] In one or more embodiments, the method further includes positioning the receiver at a location that provides optimal power transfer efficiency between the transmitter and the alignment device.

[0039] In one or more embodiments, the alignment device of the method comprises any of the alignment devices described.

[0040] Embodiments will now be described more fully with reference to the accompanying drawings. [Brief description of the drawings]

[0041] [Figure 1] FIG. 1 is a block diagram of a wireless power transfer system. [Diagram 2] FIG. 1 is a block diagram of a transmitter and receiver of a high frequency wireless power transfer system implemented in a material. [Diagram 3] FIG. 2 is a block diagram of an alignment device according to one aspect of the present disclosure. [Figure 4] FIG. 4 is a partial schematic layout diagram of a field detection unit (FDU) of the alignment device of FIG. 3. [Diagram 5] FIG. 5 is a plan view of the coils of the FDU of FIG. [Figure 6] FIG. 5 is a partial schematic layout diagram of the FDU of FIG. 4 including the alternating magnetic field present during operation. [Figure 7] 4 is a partial block diagram of another embodiment of the alignment device of FIG. 3. [Figure 8] 4 is a partial block diagram of another embodiment of the alignment device of FIG. 3. [Figure 9] 3 is a magnetic field density plot generated by the transmitter of the high frequency wireless power transfer system of FIG. 2. [Figure 10] 10 is a plan view of the magnetic field density plot of FIG. 9 including the alignment device of FIG. 8. [Figure 11] 10 is another plan view of the magnetic field density plot of FIG. 9 including the alignment device of FIG. 8 in operation. [Figure 12] 10 is another plan view of the magnetic field density plot of FIG. 9 including the alignment device of FIG. 8 in operation. [Figure 13] 10 is another plan view of the magnetic field density plot of FIG. 9 including the alignment device of FIG. 8. [Figure 14] 10 is another plan view of the magnetic field density plot of FIG. 9 including the alignment device of FIG. 8 in operation. [Figure 15] FIG. 4 is a partial schematic layout diagram of another FDU of the alignment device of FIG. 3. [Figure 16] FIG. 4 is a partial schematic layout diagram of another FDU of the alignment device of FIG. 3. [Figure 17] 4 is a partial block diagram of another embodiment of the alignment device of FIG. 3. [Figure 18] 1 is a proximity diagram showing the region of proximity of the alignment device for optimal alignment. [Figure 19] 4 is a block diagram of another embodiment of the alignment device of FIG. 3. [Figure 20A] FIG. 1 is a spatial distribution diagram of the detected magnetic field. [Figure 20B] FIG. 1 is a spatial distribution diagram of the detected magnetic field. [Figure 20C] FIG. 1 is a spatial distribution diagram of the detected magnetic field. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] The foregoing summary, as well as the following detailed description of certain examples, will be better understood when read in conjunction with the accompanying drawings. It should be understood that, as used herein, an element or feature referred to in the singular and preceded by the word "a" or "an" does not necessarily exclude a plural of that element or feature. Furthermore, reference to "one example" or "one embodiment" is not intended to be interpreted as excluding the existence of additional examples or embodiments that also incorporate the described element or feature. Moreover, unless expressly stated otherwise, an example or embodiment that "comprises" or "having" or "including" an element or feature or elements or features having a particular characteristic may include additional elements or features that do not have that characteristic. It will also be recognized that the terms "comprises," "has," and "includes" mean "including by not limited to," and that the terms "comprising," "having," and "including" have equivalent meanings. It will also be recognized that like reference characters are used to refer to like elements throughout the description and drawings.

[0043] As used herein, the terms "adapted" and "configured" mean that an element, component, or other subject matter is designed and / or intended to perform a given function. Thus, use of the terms "adapted" and "configured" should not be interpreted to mean that a given element, component, or other subject matter is merely "capable of" performing a given function, and not that the element, component, and / or other subject matter has been specifically selected, created, implemented, utilized, and / or designed for performing the function. It is also within the scope of this disclosure that elements, components, and / or other subject matter that are described as adapted to perform a particular function may additionally or alternatively be described as configured to perform that function, and vice versa. Similarly, subject matter that is described as configured to perform a particular function may additionally or alternatively be described as operable to perform that function.

[0044] When an element is referred to as being "on," "attached," "connected," "coupled," "contacting," or the like, to another element, it will be understood that the element may be directly on, attached, connected, coupled, or in contact with the other element, or there may be intervening elements present.

[0045] It should be understood that use of the word "exemplary" does not imply a preferred or optimal design or implementation, unless otherwise specified, but rather means "by way of example" or "one example."

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0047] As used herein, the terms "approximately," "about," "approximately," "generally," and the like, refer to an amount or condition that is close to a stated amount or condition that still performs a desired function or achieves a desired result. For example, the terms "approximately," "about," "approximately," "generally," and the like can refer to an amount or condition that is within an engineering tolerance readily recognized by one of ordinary skill in the art.

[0048] 1, there is shown a wireless power transfer system generally identified by reference numeral 100. The wireless power transfer system 100 comprises a transmitter 110 including a power source 112 electrically connected to a transmitting element 114, and a receiver 120 including a receiving element 124 electrically connected to a load 122. Power is transferred from the power source 112 to the transmitting element 114. Power is then transferred from the transmitting element 114 to the receiving element 124 by resonant or non-resonant electric or magnetic field coupling. Power is then transferred from the receiving element 124 to the load 122. An exemplary wireless power transfer system 100 includes a high frequency inductive wireless power transfer system as described in U.S. Patent Application Publication No. 2005 / 0139994, the relevant portions of which are incorporated herein by reference.

[0049] Referring now to FIG. 2, another exemplary wireless power transfer system is shown. In this embodiment, the wireless power transfer system is the high frequency wireless power transfer system 200 described in the above-incorporated U.S. Patent Application Publication No. 2006 / 0139994. In this embodiment, the high frequency wireless power transfer system 200 is an inductive system. Those skilled in the art will recognize that the high frequency wireless power transfer system 200 can be configured to transfer power by high frequency magnetic inductive coupling or high frequency electrocapacitive coupling. In a magnetic inductive coupling system, the majority of the power transfer is via a magnetic field. Little, if any, power is transferred by electrocapacitive or resonant electrocapacitive (electric field). In an electrocapacitive coupling system, the majority of the power transfer is via an electric field. Little, if any, power is transferred by magnetic inductive or resonant magnetic induction.

[0050] In this embodiment, the high frequency wireless power transfer system 200 is configured to transfer power by high frequency magnetic field coupling. The high frequency wireless power transfer system 200 comprises a transmitter 210 configured to operate at a given frequency and a receiver 220 configured to operate at the operating frequency of the transmitter 210. As shown in FIG. 2, the transmitter 210 is positioned in contact with a material 230. The material 230 is made of any type of suitable material or combination of materials that is not conductive or magnetic, e.g., wood, glass, stone, brick, concrete, plastic, except for materials or combinations of materials that would result in early termination of the field, i.e., act as a shield. In this embodiment, the material 230 forms part of a wall. The receiver 220 is positioned opposite the material 230 such that the material 230 is directly between the transmitter 210 and the receiver 220. Those skilled in the art will recognize that multiple transmitters 210 and receivers 220 are possible.

[0051] In this embodiment, the transmitter 210 includes a transmitter coil 212 and the receiver 220 includes a receiver coil 222. Those skilled in the art will recognize that multiple transmitter coils 212 and receiver coils 222 are possible.

[0052] The transmitter 210 operates in a current mode output (constant current output), in which the transmitter 210 is configured to generate a magnetic field without the need for the receiver 220 to be in close proximity to the transmitter 210.

[0053] Generally, a current-mode output high-frequency wireless power transfer system differs from a voltage-mode output (constant voltage output) high-frequency wireless power transfer system in that a voltage-mode output transmitter 210 cannot generate and maintain a magnetic field unless a receiver 220 is present in the vicinity of the transmitter 210. If a receiver 220 is not present in a voltage-mode output high-frequency wireless power transfer system, the transmitter 210 will essentially be operating in a short circuit condition and therefore will not be able to sustain the generation of a magnetic field.

[0054] Power transfer from the transmitter 210 to the receiver 220 occurs through the material 230. To maximize the coupling coefficient value and maximum power transfer efficiency, the transmitter 210 and receiver 220 should be optimally aligned. Optimal alignment of the transmitter 210 and receiver 220 can be problematic if the material 230 is opaque or completely blocks the view of either the transmitter 210 or receiver 220 or both locations.

[0055] When the receiver 220 is optimally aligned with the transmitter 210 , the receiver coil 222 is in optimal alignment with the transmitter coil 212 .

[0056] 3, a block diagram of an alignment device 300 according to one embodiment of the present disclosure is shown. Given a certain fixed distance away from the transmitter 210, the alignment device 300 determines the position where the transmitter 210 and receiver 220 are optimally aligned when the receiver 220 is installed to achieve the maximum coupling coefficient value and therefore the highest power transfer efficiency. The transmitter coil 212 and receiver coil 222 are optimally aligned when their central axes perpendicular to the transmitter coil 212 and receiver coil 222 are collinear. The central axes of the transmitter coil 212 and receiver coil 222 are axes that run through the centers of mass of the respective coils 212 and 222.

[0057] In particular, the alignment device 300 is configured to generate an induced voltage from the magnetic field generated by the transmitter 210. Specifically, the alignment device 300 is configured to generate an induced alternating voltage when crossed by the alternating magnetic field generated by the transmitter 210. Based on the induced alternating voltage, the alignment device 300 is configured to determine a position of the alignment device 300 relative to the transmitter 210 or the transmitter coil 212. The receiver 220 and the receiver coil 222 may then be positioned at a position that maximizes power transfer efficiency between the transmitter coil 212 and the receiver coil 222 as determined by the alignment device 300.

[0058] The alignment device 300 comprises a field detection unit (FDU) 310 and a main board 318. The FDU 310 comprises at least one coil 312, at least one tuning capacitor 314, and a rectifier 316. The coil 312 is electrically connected to the tuning capacitor 314. The tuning capacitor 314 is electrically connected to the coil 312 and the rectifier 316. The FDU 310 is electrically connected to the main board 318. In particular, the rectifier 316 of the FDU 310 is electrically connected to a voltage divider 320 of the main board 318. The main board 318 comprises the voltage divider 320, a comparator, which in this embodiment takes the form of a comparator circuit 322, a sensitivity control 323, and an indicator 324. The voltage divider 320 is electrically connected to the rectifier 316 of the FDU 310. The voltage divider 320 is also electrically connected to the comparator circuit 322. The comparator circuit 322 is electrically connected to an indicator 324 via a drive circuit (not shown). The indicator 324 is electrically connected to the comparator circuit 322 via a drive circuit (not shown).

[0059] The comparator circuit 322 is configured to compare the voltage signal of the rectifier 316 with a preset threshold voltage. In this embodiment, the indicator 324 associated with the FDU 310 is a light emitting diode (LED). The LED is driven by an LED driving circuit (not shown). The LED driving circuit, which in this embodiment comprises a transistor (not shown), is triggered by the output from the comparator circuit 322. The sensitivity control 323 is electrically connected to the comparator circuit 322. The sensitivity control 323 is configured to adjust and set the threshold voltage. In this embodiment, the sensitivity control 323 is a rotary knob or dial, etc.

[0060] The indicators 324 aid in determining an optimal alignment position where maximum coupling coefficient and highest wireless power transfer efficiency is achieved. For example, the indicators 324 include visual indicators including, but not limited to, LEDs or other types of lights / diodes, audible indicators, any type of sensory indicator including, but not limited to, vibration, and any combination of available types of indicators 324, not limited to the types of indicators described herein.

[0061] Those skilled in the art will appreciate that multiple FDUs 310 may be mounted on a single main board 318. Furthermore, those skilled in the art will appreciate that multiple indicators 324 may be on a single main board 318. For example, each FDU 310 may be provided with one indicator 324.

[0062] In this embodiment, the alignment device 300 is configured for use with the high frequency inductive wireless power transfer system described in the above-incorporated U.S. Patent Application Publication No. 2006 / 0139993. In this embodiment, the alignment device 300 is configured to operate with the current-mode output transmitter 210 independent of and in the absence of the receiver 220.

[0063] In a voltage mode output high frequency wireless power transfer system, the alignment device 300 cannot be used without the presence of the receiver 220. Thus, in a voltage mode output high frequency wireless power transfer system, the alignment device 300 is incorporated into the receiver 220. Conversely, the current mode output high frequency wireless power transfer system 200 allows the alignment device 300 to operate while physically separate from (i.e., decoupled from) the receiver 220, thereby allowing the alignment device 300 to operate independently with the transmitter 210 when the receiver 220 is completely absent. Those skilled in the art will recognize that the alignment device 300 may alternatively be incorporated into the receiver 220 of a current mode output high frequency wireless power transfer system.

[0064] 4, the FDU 310 of the alignment device 300 is further shown. As previously described, the FDU 310 comprises at least one coil 312. The coil 312 is electrically connected in series with a tuning capacitor 314. The tuning capacitor 314 is electrically connected to the coil 312 and to a rectifier 316. The electrically connected combination of the coil 312, the tuning capacitor 314, and the rectifier 316 forms the FDU 310. The FDU 310 is electrically connected to a main board 318. In this embodiment, the alignment device 300 comprises a single FDU 310. In another embodiment, the alignment device 300 comprises multiple FDUs 310, for example, four FDUs 310. Each FDU 310 is identical.

[0065] 5, the coil 312 is further shown. In this embodiment, the coil 312 is mounted to a PCB made of FR4 printed circuit board (PCB) material. In this embodiment, the coil 312 is a planar coil made of multiple turns and is roughly square in shape. In this embodiment, the total number of turns of the coil 312 is 4, each turn is 1 mm thick, and the spacing between each turn is 0.3 mm. Those skilled in the art will recognize that the coil 312 can be any other shape, such as, but not limited to, a spiral, a circular, a hexagon, or an octagon. Those skilled in the art will also recognize that the number of turns, the thickness of the turns, and the spacing between the turns can be any suitable value. In this embodiment, the coil 312 has an outer width / height D1 of 39 mm and an inner width / height D2 of 29.5 mm. Those skilled in the art will recognize that the dimensions D1 and D2 of the coil 312 can be any suitable value. In this embodiment, the inductance (L) of the coil 312 is 1.2 μH. Those skilled in the art will recognize that the inductance of the coil 312 is exemplary. The inductance may be as high as 6-8 μH. Generally, the inductance of the coil 312 is constrained by the resonant frequency of the transmitter coil 212. As the inductance of the coil 312 increases, the self-resonant frequency of the coil 312 decreases, which may cause the self-resonant frequency of the coil 312 to approach the resonant frequency, which may be problematic. However, a higher inductance may result in higher sensitivity and field detection during operation of the alignment device 300.

[0066] Optimal placement of the alignment device 300 corresponds to optimally aligning the receiver 220 relative to the transmitter 210. Optimal alignment of the transmitter 210 and receiver 220 corresponds to optimally aligning the transmitter coil 212 and receiver coil 222. The optimal alignment of the transmitter coil 212 and receiver coil 222 is the position where the maximum coupling coefficient value and highest wireless power transfer efficiency are achieved.

[0067] During operation, the transmitter 210 of the wireless power transfer system 200 is activated and powered up. The transmitter coil 212 generates a constant alternating current (AC) magnetic field. The receiver 220 may be aligned with the transmitter 210 such that power can be wirelessly transferred from the transmitter coil 212 to the receiver coil 222. For optimal alignment between the transmitter 210 and receiver 220, the transmitter coil 212 and receiver coil 222 must be in optimal alignment. If the transmitter coil 212 and receiver coil 222 are not optimally aligned, coupling and power transfer can occur, but performance of the wireless power transfer system 200 will be degraded.

[0068] As mentioned above, given a certain fixed distance away from the transmitter 210, the alignment device 300 determines the position where the transmitter 210 and receiver 220, when installed, are in optimal alignment to achieve the maximum coupling coefficient value and therefore the highest power transfer efficiency. The transmitter coil 212 and receiver coil 222 are in optimal alignment when their central axes perpendicular to the transmitter coil 212 and receiver coil 222 are collinear. In other words, the transmitter coil 212 and receiver coil 222 are in optimal alignment when the axes extending through the centers of mass of the respective coils 212 and 222 are collinear.

[0069] During operation of the alignment device 300, the coil 312 is crossed by an AC magnetic field generated by the transmitter coil 212. The coil 312 generates an induced alternating voltage from the AC magnetic field. The induced voltage is used to determine the position of the alignment device 300 relative to the transmitter 210 of the high frequency wireless power transfer system 200 operating in a constant current mode in the transmitter coil 212.

[0070] Specifically, the tuning capacitor 314 of the FDU 310 tunes the coil 312 to the resonant frequency of the transmitter coil 212 to generate an induced voltage from the AC magnetic field. The coil 312 induces an alternating voltage from the AC magnetic field and outputs an AC voltage signal. The induced alternating voltage is proportional to the strength of the AC magnetic field. The AC voltage signal is passed from the coil 312 to a rectifier 316. The rectifier 316 rectifies the voltage signal from AC to DC. The DC voltage signal is then passed to the main board 318. The voltage divider 320 scales down the DC voltage signal so that the DC voltage signal is compatible with the logic levels of the main board 318. In this embodiment, the scale-down factor of the voltage divider 320 is 10. However, one skilled in the art will recognize that the scale-down factor can be any other suitable value depending on the design of the main board 318. Specifically, the voltage divider 320 scales down the DC voltage so that the DC voltage signal can be compared by the comparator circuit 322. The scaled down DC voltage is measured by the comparator circuit 322. The comparator circuit 322 compares the scaled down DC voltage with a preset threshold voltage provided by the sensitivity control 323. If the voltage is highest (i.e., exceeds the threshold set by the sensitivity control 323 in the comparator circuit 322), the optimal alignment (or near optimal alignment) is achieved. The comparator circuit 322 passes the result of the comparison to the indicator 324. The comparison of the scaled down DC voltage / preset threshold voltage determines whether to switch on the indicator 324. Specifically, the comparison determines whether to switch on the LED of the indicator 324. The indicator 324 indicates whether the optimal alignment is achieved.

[0071] The alignment device 300 allows the transmitter 210 and receiver 220 to be positioned on either side of a material 230, such as a wall or a window. The alignment device 300 allows the optimal positions of the transmitter coil 212 and receiver coil 222 to be determined, thus achieving a maximum coupling coefficient value and highest wireless power transfer efficiency through the material 230.

[0072] As shown in Figure 6, during operation of the alignment device 300, the coil 312 is exposed to an AC magnetic field in a direction indicated by arrow A. When exposed to an AC magnetic field, the coil 312 is crossed by an alternating magnetic field. The AC magnetic field crossing the coil 312 induces an alternating voltage in the coil 312. Figure 6 shows an example of the direction of the magnetic field lines relative to the coil 312.

[0073] Although a particular configuration of the alignment device 300 has been described, one skilled in the art will recognize that other configurations are possible. Referring now to FIG. 7, there is shown another embodiment of an alignment device generally identified by reference numeral 700. The alignment device 700 includes all of the elements of the alignment device 300 previously described, unless otherwise noted. The alignment device 700 functions similarly to the alignment device 300 previously described, unless otherwise noted. The alignment device 700 includes three FDUs 710, each of which includes a coil 712, at least one tuning capacitor 714, and a rectifier 716. The three FDUs 710 are coplanar and arranged in an equilateral formation. Each FDU 710 is electrically connected to a main board (not shown). The main board of the alignment device 300 is identical to the main board 318 previously described. In the illustrated embodiment, the main board is integrated into the control / logic module 750 .

[0074] Using three coils 712, the module 750 is configured to triangulate the optimal position of the coils 712 relative to the transmitter coil 212. When all coils 712 are equally (or nearly equally) crossed by the alternating magnetic field, optimal alignment is achieved, as will be described. Those skilled in the art will recognize that the alignment device may also comprise further control and logic components, including but not limited to the use of a microprocessor, microcontroller, logic processor, or other possible controller.

[0075] FIG. 8 illustrates another embodiment of an alignment device generally identified by reference numeral 800. The alignment device 800 includes all the elements of the alignment device 300 described above, unless otherwise stated. The alignment device 800 functions similarly to the alignment device 300 described above, unless otherwise stated. The alignment device 800 includes four coplanar FDUs 810. Each FDU 810 includes a coil 812, at least one tuning capacitor 814, and a rectifier 816. Thus, the alignment device 800 includes four coils 812, four tuning capacitors 814, and four rectifiers 816. Each of the four coils 812 is electrically connected to a different tuning capacitor 814. Each of the four tuning capacitors 814 is electrically connected to a different rectifier 816. Each FDU 810 is electrically connected to a main board (not shown). The main board of the alignment device 800 is identical to the previously described main board 318. Thus, each rectifier 816 of each FDU 810 is electrically connected to a voltage divider 320 of the main board 318.

[0076] In this embodiment, the FDUs 810 are positioned orthogonally to one another. The FDUs 810 are coplanar and positioned in the XY plane, except that two FDUs 810 are opposed to one another and laterally spaced apart from one another along the X axis, and two FDUs 810 are orthogonally opposed to one another and laterally spaced apart from one another along the Y axis.

[0077] In this embodiment, the alignment device 800 comprises four FDUs 810, each having a coil 812. The coils 812 are positioned at a fixed distance from each other to detect the strength of the AC magnetic field generated by the transmitter 210. The detected magnetic field strength value at each coil 812 is used to determine the optimal alignment position. In this embodiment, the indicators on the main board of the alignment device 800 are LEDs. Similar to the alignment device 300, the alignment device 800 comprises a main board 318 comprising a voltage divider 320, a comparator 322, which in this embodiment takes the form of a comparator circuit, a sensitivity control 323, and one indicator 324 for each FDU. The main board and the components comprised thereon are identical to the main board 318 and the components comprised thereon described above. In this embodiment, the sensitivity control is a rotary knob or dial or the like.

[0078] 9, an example of a magnetic field density plot generated from a single transmitter 210 of a high frequency wireless power transfer system 200 is shown. As shown in FIG. 9, the magnetic field is stronger along the central axis of the transmitter coil 212 and weaker near the edges of the plot. Efficient coupling between the transmitter coil 212 and the receiver coil 222 occurs when the transmitter coil 212 and the receiver coil 222 are aligned along their central axes such that the coupling coefficient is maximized. As previously mentioned, the alignment device 800 detects the strongest magnetic field from the transmitter 210 along its central axis to determine the optimal alignment position where the receiver 220 will be implemented.

[0079] In operation, the alignment device 800 is positioned in proximity to the transmitter coil 212. The alignment device 800 is positioned such that a magnetic field intersects at least one of the coils 812 of one of the FDUs 810 of the alignment device 800, thereby inducing an AC voltage in at least one of the coils 812 of the alignment device 800. The alternating magnetic field intersecting the coils in the FDU 810 will induce an alternating voltage in the coil 812. The induced alternating voltage is rectified to a DC voltage via the rectifier 816. The positioning of the alignment device 800 may be a manual or automated method.

[0080] 10, an alignment device 800 including four FDUs 810 is shown above a magnetic field density plot generated from a single transmitter 210 of a high frequency wireless power transfer system 200. Depending on the position of the alignment device 800 relative to the transmitter coil 212 of the transmitter 210, the coil 812 closest to the center of the transmitter coil 212 will have the highest rectified voltage due to the stronger magnetic field. The remaining coils 812 will have lower rectified voltages. The coil 812 with the highest rectified (scaled down) voltage will exceed a pre-set threshold voltage, which will trigger an indicator 824. The threshold voltage is set by a voltage sensitivity control 823 connected to a comparator circuit 822 on the main board 318. As a result, the alignment device 800 is now repositioned toward the coil 812 with the highest voltage.

[0081] 11 shows that as the alignment device 800 moves in the direction of the highest commutated voltage, the next coil 812, now closer to the center of the magnetic field, will now have a rise in its commutated voltage. Also as shown in FIG. 11, the next coil that has a rise in its commutated voltage must be orthogonal to the first coil 812.

[0082] 10, if the first coil 812 with the highest rectified voltage is the left coil 812 of FDU 810(A), then the next coil 812 with an increased rectified voltage will be either the top coil 812 of FDU 810(B) or the bottom coil 812 of FDU 810(C). Based on the degree of orthogonality, the next coil 812 with an increased rectified voltage cannot be the FDU 810(D) coil 812. When both the coil 812 of FDU 810(B) and the coil 812 of FDU 810(C) are shown to be equidistant from the x-axis and the alignment device 800 is aligned along the x-axis, it is possible that the coils 812 of both FDU 810(B) and FDU 810(C) can have equal or nearly equal increases in rectified voltage at the same time.

[0083] When the first coil 812 of the FDU 810(A) crosses the magnetic field of the transmitter 210, the rectified voltage is scaled down through the voltage divider 320 and then measured by the main board 318, which sends the voltage data to the comparator circuit 322. The comparator circuit 322 compares the rectified voltage of the FDU 810(A) with a preset threshold voltage. When the rectified voltage of the FDU 810(A) exceeds the preset threshold voltage, a signal is sent from the main board 318 to activate the indicator 324 associated with the FDU 810(A). The comparison of the rectified voltage with the preset threshold voltage by the comparator circuit 322 is repeated throughout the alignment method. When the rectified voltage is higher or lower than the preset threshold, the indicator 324 will be turned on and off. The activation of the indicator 824 indicates the direction in which the alignment device 800 should reposition to achieve alignment of the other FDU 810. When all indicators 824 are activated, the alignment device 800 is in an optimal alignment state, with all coils 812 being crossed by an alternating magnetic field along the central axis of the transmitter coil 212. Following the crossing of the magnetic field with the coil 812 of the FDU 810(A) and the activation of the indicators 824, the alignment device 800 can be repositioned to a new orientation based on the position of the second coil 812 of the different FDU 810. In this embodiment, the second coil 812 is either the coil 812 of the FDU 810(B) or the FDU 810(C). For example, when the coil 812 of the FDU 810(B) is crossed by the magnetic field and the rectified voltage exceeds a preset threshold voltage, the indicator 824 for the FDU 810(B) is activated.

[0084] As this alignment method continues, the alignment device 800 is repositioned based on the intersection of the magnetic field with the coil 812 of the FDU 810 and the subsequent activation of the indicator 824. The third FDU 810 coil 812 will then have a rise in voltage. Depending on the movement of the alignment device 800, the next coil 812 to have a rise in rectified voltage will be the coil 812 of either the FDU 810(C) or the FDU 810(D). As previously mentioned, the coil 812 must be positioned orthogonal from the coil 812 that already has a raised voltage. In this example, the coil 812 of the FDU 810(C) or the coil 812 of the FDU 810(D) may be activated based on the direction of movement relative to the alternating magnetic field from the transmitter 210. Therefore, in this embodiment, the third coil 812 to be activated must be orthogonal to the coils 812 of FDU 810(A) or FDU 810(B), as shown in FIG.

[0085] Finally, when three of the four coils 812 are crossed by a magnetic field and their associated indicators 824 are activated, the alignment device 800 will now move in the average direction of the activated indicators 824. In this embodiment, the alignment device 800 must move toward the indicators activated by the coils 812 of FDU 810(A). By moving the alignment device 800 in the general direction of the coils 812 of FDU 810(A), as shown in FIG. 13, the coils 812 of FDU 810(D) will have a rise in rectified voltage. Once the voltages at all coils 812 are equal (or nearly equal) and all four indicators 824 are activated, the alignment device 800 is now in a position where the magnetic fields crossing all four coils 812 are equal (or nearly equal) in strength, as shown in FIG. 14. As a result, this position of the alignment device 800 should be the optimal aligned position where the maximum coupling coefficient value and highest wireless power transfer efficiency are achieved.

[0086] When the alignment device 800 is in an optimal aligned position, its position can be marked on the material 230 on which the receiver 220 is to be mounted. Marking of the position can be performed with a writing implement through a through-hole on the alignment device 800. The through-hole on the alignment device 800 corresponds to the coordinates of the mounting point on the receiver 220. The writing implement can be a pencil, pen, marker, etc., or any thin, pointed, or sharp object that can fit into the through-hole of the alignment device 800 to mark or indent the material 230 on which the receiver 220 is to be mounted and aligned with the transmitter 210.

[0087] Although a specific FDU has been described, one of ordinary skill in the art will recognize that other configurations are possible. Referring now to FIG. 15, another embodiment of an alignment device FDU 910 is shown. The FDU 910 is generally referred to as a pin diode configuration. In this embodiment, the FDU 910 comprises at least one coil 912. The coil 912 is identical to the coil 312 previously described unless otherwise noted. The coil 912 is electrically connected to three parallel capacitors 902, 904, 906 having capacitances C1, C3, and C4, respectively. As with the FDU 310, the capacitors 904 and 906 are connected to a rectifier formed of a parallel connected diode 916 (D3), a diode 918 (D2) connected in series with the capacitor 904, a capacitor 920 connected in parallel between the diodes 916 and 918, and a resistor 922 with resistance R connected in parallel with the capacitor 920. The voltage at the resistor 922 is given as Vo.

[0088] The FDU 910 further comprises a diode 930 (D1) connected to the capacitor 902, and a capacitor 932 having a capacitance C2 connected to the diode 930. The diode 930 is connected in parallel to two choke inductors 940, 942 having inductances L1 and L2, respectively. Each choke inductor 940, 942 blocks only AC current and allows only DC current. Each inductor 940, 942 is connected in series with a resistor 944, 946, respectively. Each resistor 944, 946 is connected in series with a voltage source 950, 952 having a voltage V1 and V2, respectively.

[0089] In the arrangement shown, diode 930 (D1) is a pin diode. Diode 930 is ON, i.e., current flows through diode 930, when voltage V1 is higher than voltage V2, and is OFF, i.e., current does not flow through diode 930, when voltage V1 is lower than voltage V2. Diode 930 is used to "switch in" capacitors 902 and 932 to reduce the resonant frequency of coil 312.

[0090] Capacitance C A is the frequency f A is defined as the cumulative capacitance (C1, C2, C3, and C4) of the capacitors 902, 932, 904, and 906 at B is the frequency f B is defined as the cumulative capacitance (C1, C2, C3, and C4) of capacitors 902, 932, 904, and 906 at frequency f A is equal to 6.78MHz, and the frequency f B is equal to 13.56MHz. When the diode 930 (D1) is OFF, the capacitance C B is achieved, and when the diode 930 (D1) is ON, the capacitance C A is achieved.

[0091] Given the stated frequency, frequency f B teeth, f B =2*f A (1) The frequency f expressed in equation (1) as A is equal to twice the

[0092] There is a square relationship between frequency and capacitance, so doubling the frequency effectively quadruples the capacitance in the circuit. Hence, the capacitance C A teeth, C A =4*C B (2) The capacitance C expressed in equation (2) as B is equal to four times

[0093] For a given value of capacitance C4, capacitance C3 is

[0094]

number

[0095] This can be expressed in equation (3).

[0096] The capacitance C1 is equal to the capacitance C2, and the equivalent capacitance C τ When is equal to twice the capacitance C1 or C2, the equivalent capacitance C τ teeth,

[0097]

number

[0098] This can be expressed in equation (4).

[0099] Equivalent capacitance C τ is the equivalent capacitance of the capacitors 902, 932 when the diode 930 is ON. The capacitance C4 is chosen large enough to avoid negative values ​​for the capacitance C3. The capacitance C3 is the equivalent capacitance C τis chosen small enough to allow for it to be positive.

[0100] 16, another embodiment of the alignment device FDU 954 is shown. The FDU 954 is generally referred to as a metal oxide semiconductor field effect transistor (MOSFET) configuration. In this embodiment, the FDU 954 comprises at least one coil 956. The coil 956 is identical to the coil 312 described above unless otherwise noted. The coil 956 is electrically connected to three parallel capacitors 958, 960, 962 having capacitances C1, C2, and C3, respectively. As with the FDU 310, the capacitors 958, 960 are connected to a rectifier formed of a parallel connected diode 964, a diode 966 connected in series with the capacitor 958, a capacitor 968 connected in parallel between the diodes 964, 966, and a resistor 970 with resistance R connected in parallel with the capacitor 968. The voltage at the resistor 970 is given as Vo.

[0101] Capacitor 962 is connected to a pair of oppositely positioned transistors 972, 974 which are connected to a capacitor 968. Transistors 972, 974 are configured to switch the raised capacitance of capacitor 962 into or out of the resonant circuit of FDU 954. The resonant circuit comprises coil 956 of FDU 954 and other resonant components, namely capacitors 958, 960, 962, 968.

[0102] A resistor 976 is connected in parallel between the transistors 972, 974. The resistor 976 is a choke insulator resistor. The choke insulator resistor is connected to ground. The resistors 972, 974 are configured to prevent AC signals from spanning across both transistors 972, 974 when they are in their powered off state. The transistors 972, 974 are connected at their drains to a voltage source 980 having a voltage Vc. The voltage source 980 is an AC voltage source.

[0103] The drain of transistor 972 is connected to capacitor 962, while the source of transistor 972 is connected to the source of transistor 974. The drain of transistor 974 is connected to capacitor 968. When powered off, transistors 972 and 974 act as diodes.

[0104] If a single transistor 972, 974 were present instead of two transistors 972, 974, a sufficiently high voltage (typically greater than 0.7 volts) would pass through on either the positive or negative waveform of the voltage source 980.

[0105] If two transistors 972, 974 are connected in series and their diode-like orientation is reversed, i.e., the sources of each transistor are connected together, then what passes through one transistor does not pass through the other transistor. Resistor 976 maintains a zero reference DC voltage between transistors 972, 974.

[0106] The relationship between resonant frequency and inductor / capacitor is:

[0107]

number

[0108] where f is the frequency of the magnetic field to be detected, L is the inductance of the coil 956, and C is the capacitance of the resonant circuit of the FDU 954.

[0109] The equivalent capacitance of the resonant circuit when transistors 972, 974 are allowing current to flow is C low The equivalent capacitance of the resonant circuit when transistors 972, 974 are not allowing current to flow is given by C high In the low frequency use case, the capacitance (Cfet ) is negligible and may be ignored. The required inductance of the coil 956 and the capacitances C1, C2, C3 of the capacitors 958, 960, 962, respectively, may be calculated accordingly for a given frequency, e.g., 6.78 MHz.

[0110] 17, another embodiment of an alignment device is generally identified by the reference numeral 1000. The alignment device 1000 includes all the elements of the alignment device 300 described above, unless otherwise stated. Similarly, the alignment device 1000 functions similarly to the alignment device 300 described above, unless otherwise stated. The alignment device 1000 includes five coplanar FDUs 1010. Each FDU 1010 includes a coil 1012, at least one tuning capacitor 1014, and a rectifier 1016. Thus, the alignment device 1000 includes five coils 1012, five tuning capacitors 1014, and five rectifiers 1016. Each of the five coils 1012 is electrically connected to a different tuning capacitor 1014. Each of the five tuning capacitors 1014 is electrically connected to a different rectifier 1016. Each FDU 1010 is electrically connected to a main board (not shown), which, unless otherwise noted, is identical to the main board 318 previously described. Each rectifier 1016 of each FDU 1010 is electrically connected to a voltage divider 320 on the main board 318.

[0111] In this embodiment, the FDUs 1010 are positioned orthogonally to one another. Two FDUs 1010 (indicated by letters B and D) are coplanar and positioned in the XY plane, except that the two FDUs 1010 are opposite one another along the X axis, laterally spaced apart from one another, and equidistant to a central FDU 1010 (indicated by letter C). Two other FDUs 1010 (indicated by letters A and E) are orthogonally opposite one another along the Y axis, laterally spaced apart from one another, and equidistant to a central FDU 1010 (C).

[0112] The coils 1012 are positioned at fixed distances from each other to detect the strength of the AC magnetic field generated by the transmitter 210. The detected field strength values ​​at each coil 1012 are used to determine an optimal alignment position.

[0113] As shown in Fig. 17, the alignment device further comprises a control / logic module 1050. Similar to the alignment devices 300 and 800, the alignment device 1000 comprises a main board, which in the embodiment shown is integrated into the module 1050. The main board 318 comprises a voltage divider 320, a comparator 322, which in this embodiment takes the form of a comparator circuit, a sensitivity control 323, and an indicator 324. In the embodiment shown, the main board comprises five indicators, each associated with an FDU 1010 of the alignment device 1000. The main board and the components comprised thereon are the same as the main board and the components comprised thereon previously described. In this embodiment, the indicators are LEDs. In this embodiment, the sensitivity control 323 is a rotary knob or dial or the like. The module 1050 may further comprise a microcontroller, a microprocessor, a computer, or any other computing means. The module 1050 may further comprise suitable storage means, for example a computer readable memory, and one or more processors.

[0114] Module 1050 is configured to analyze field strength in two directions, vertical and horizontal. In one embodiment, module 1050 receives a voltage detected by FDU 1010. Module 1050 analyzes the received voltage and controls an indicator associated with FDU 1010. In particular, module 1050 controls one or more LEDs to operate and illuminate sequentially or in a repeating pattern. Module 1050 can control the time between turning on and off the LEDs. Module 1050 controls the indicator to remain in an off state until it is operated, e.g., controlled to be turned on.

[0115] In the illustrated arrangement, the field is a magnetic field. Module 1050 is configured to analyze field strength in vertical and horizontal directions that are independent of each other. Magnetic field data collected from FDU 1010 (B, C, D) forms horizontal field data. Magnetic field data collected from FDU 1010 (A, C, E) forms vertical field data. The collected horizontal and vertical field data are analyzed in module 1050.

[0116] When the highest voltage is detected in the central FDU 1010(C) compared to all detected voltages in its associated coils 1012, the alignment device 1000 is aligned with the transmitter 210 and the optimal position of the receiver is determined.

[0117] In use, the alignment device 1000 is positioned in a two-dimensional plane (the XY plane) that has a fixed orthogonal distance from the plane of the transmitter 210 and associated transmitter coil 212. The orthogonal distance is determined by the thickness of the material 230 that separates the alignment device 1000 from the transmitter 210. When the material 230 has a uniform thickness, the two-dimensional planes of the alignment device 1000 and the transmitter 210 are parallel to each other.

[0118] First, the FDU 1010 detects voltage at various frequencies, for example, two frequencies, 6.78 MHz and 13.56 MHz, to determine at which frequency the detected voltage is higher. Based on the higher detected voltage, the module 1050 determines at which frequency the transmitter 210 is operating and controls the FDU 1010 to detect voltage at this frequency.

[0119] The comparison between the voltages is based on a running average of the voltage at each coil 1012 of the FDU 1010 to avoid unstable LED operation.

[0120] If no voltage is detected, the alignment device 1000 stops detecting voltage for a predetermined amount of time or until the user instructs the alignment device 1000 to detect voltage again to conserve power. In this configuration, the alignment device 1000 is in standby mode. Standby mode is indicated by one LED on each FDU 1010 being lit at a time in a clockwise pattern.

[0121] Once module 1050 has determined the frequency at which transmitter 210 is operating, all five FDUs 1010 collect voltages which are forwarded to module 1050. As described above, module 1050 analyzes the horizontal and vertical data separately.

[0122] Module 1050 determines in which direction the center of the magnetic field is located from the horizontal field data (from FDU1010B, FDU1010C, FDU1010D) and from the vertical field data (from FDU1010A, FDU1010C, FDU1010E). If the alignment device 1000 is significantly misaligned and the direction cannot be determined, the LED associated with the FDU 1010 will flash along the direction of misalignment.

[0123] 18, the alignment device 1000 may be in different regions before being in optimal alignment. Specifically, the alignment device 1000 may be in an outer region (low proximity) 1064, an inner region (medium proximity) 1062, and an aligned spot 1060. The aligned spot 1060 corresponds to the area where optimal alignment with the transmitter 210 is achieved.

[0124] When the alignment device 1000 approaches alignment from afar, it is in an outer region (low proximity) 1064. In this outer region 1064, one LED associated with the FDU 1010 is lit to indicate where the center of the magnetic field (and alignment), i.e., spot 1060, is located and, accordingly, in which direction the device 1000 should move. When the alignment device 1000 enters the inner region (medium proximity) 1062, the LED pointing away from the spot 1060 starts to blink at a low frequency and increases in frequency as the device 1000 approaches the spot 1060 and optimal alignment. When the alignment device 1000 is aligned with the spot 1060 in optimal alignment, both of the aforementioned LEDs remain ON without blinking.

[0125] This method may be performed separately for both vertical and horizontal alignment, or simultaneously for both vertical and horizontal alignment.

[0126] In certain embodiments, if the alignment device 1000 does not detect a significant magnetic field for a specified period of time, the alignment device 1000 may power down. The alignment device 1000 may power up after a period of time or upon activation by a user as previously described.

[0127] Although particular configurations of the main boards 310 and 810 have been described above, one of ordinary skill in the art will recognize that other configurations are possible. Referring now to FIG. 19, a block diagram of another embodiment of an alignment device is generally identified by reference numeral 1300. The alignment device 1300 includes all of the elements of the alignment device 300 described above unless otherwise noted. In this embodiment, the main board 1318 includes a voltage divider 1320, an analog-to-digital (A / D) converter 1326, a microcontroller 1328, a sensitivity control 1323, and one or more indicators 1324. The voltage divider 1320 is electrically connected to the rectifier 1316 of the FDU 1310. The voltage divider 1320 is also electrically connected to the A / D converter 1326. The A / D converter 1326 is electrically connected to the voltage divider 1320 and the microcontroller 1328. The sensitivity control 1323 is connected to a microcontroller 1328. Those skilled in the art will appreciate that the microcontroller 1328 may take the form of a computer. Moreover, those skilled in the art will appreciate that the microcontroller 1328 may be readily replaced by a microprocessor 328. Those skilled in the art will appreciate that multiple FDUs 1310 may be mounted on a single main board 1318, and thus multiple indicators 1324 are possible.

[0128] The voltage divider 1320 is configured to scale down the rectified voltage from the rectifier 1316. The A / D converter 1326 is configured to convert the analog voltage from the voltage divider 1320 into a digital voltage signal. The digital voltage signal is then processed by the microcontroller 1328. Specifically, the digital voltage signal is provided to the microcontroller 1328, where a comparison between the digitized voltage and a preset threshold voltage is made using a software algorithm rather than a hardware comparator circuit 322. When the digital voltage signal exceeds the preset threshold voltage, the microcontroller 1328 is configured to signal and activate the indicator 1324. Specifically, the microcontroller 1328 activates the indicator 1324 when the rectified voltage exceeds the threshold voltage.

[0129] Although alignment devices have been described, one of ordinary skill in the art will recognize that other configurations are possible. In another embodiment, any of the alignment devices described can further comprise a spirit level. The spirit level (also known as a bubble level or level) can improve the ease of use of the alignment device. In this embodiment, the spirit level is generally cylindrical and plastic, although other shapes and materials are possible.

[0130] The level ensures level placement of both the transmitter coil 212 and the receiver coil 222. Incorporating a level into the alignment device reduces the number of tools and personnel required to align the described transmitter coil 212 and receiver coil 222, respectively.

[0131] Although a particular use case of the described alignment device has been described, one skilled in the art will recognize that other use cases are possible. In particular, any of the described alignment devices can be used to create a spatial distribution of the detected magnetic field. In this embodiment, the alignment device further includes an accelerometer to measure the acceleration of the device. The detected voltages from the coils of all the FDUs are combined with the acceleration data collected by the accelerometer to create a spatial distribution of the magnetic field.

[0132] An exemplary spatial distribution diagram of the detected magnetic field is shown in Figure 20A. As shown in Figure 20A, the central spot 1100 in the diagram indicates the position of optimal alignment.

[0133] For example, there may be cases where the spatial distribution map may be distorted when a metallic object such as a wire bundle or mesh is present in the detection area. In this case, the spatial distribution map may show a "magnetic footprint." Figure 20B shows such a magnetic footprint as the footprint of a wire bundle 1102 on the spatial distribution map. Figure 20C shows another magnetic footprint as the footprint of a metal mesh 1104.

[0134] Those skilled in the art will recognize that the alignment device 300 can be separate or part of the receiver 220. When the alignment device 300 is part of the receiver 220 or built into the receiver 220, for example, there is no need to mark the position through a through hole, since the alignment of the alignment device simultaneously aligns the receiver to an optimal position for the most efficient transfer of power from the transmitter 210 to the receiver 220.

[0135] Although particular alignment devices have been described, one of ordinary skill in the art will recognize that other configurations are possible. In another embodiment, the described alignment devices further comprise controls and / or logic configured to apply particular logic to signals within the alignment device and control the alignment device. In one embodiment, the controls and logic comprise a microprocessor, microcontroller, display, speaker, touchpad, buttons, knobs, switches, or other types of controls and logic elements.

[0136] While the described alignment device includes one or more coils and is configured for use in generating an induced voltage from a magnetic field, one skilled in the art will recognize that other configurations are possible. In another embodiment, each FDU of the described alignment device includes an electrode as opposed to a coil. Furthermore, in this embodiment, each FDU includes at least one tuning coil as opposed to at least one tuning capacitor. The tuning coil is configured to tune the electrode to a resonant frequency of the transmitter. The electrodes of the alignment device are configured to generate an induced voltage from the electric field to determine the position of the alignment device relative to the transmitter or transmitter coil of the wireless power transfer system. The electrodes can take the form of any of the electrodes described in U.S. Patent Application Publication No. 2009 / 0133991, the relevant portions of which are incorporated herein by reference.

[0137] Although an optimal alignment has been described for the transmitter 210 with the transmitter coil 212 and the receiver 220 with the receiver coil 222, one skilled in the art would recognize that other configurations are possible. In another embodiment, the transmitter 210 includes one or more capacitive electrodes and the receiver 220 includes one or more capacitive electrodes. The described alignment device determines the optimal alignment of the transmitter 210 and the receiver 220 to achieve the maximum coupling coefficient value and therefore the highest power transfer efficiency. The transmitter capacitive electrode and the receiver capacitive electrode are in optimal alignment when their central axes perpendicular to the transmitter capacitive electrode and the receiver capacitive electrode are collinear. The central axis of each of the capacitive electrodes is an axis that extends through the center of mass of the respective capacitive electrode. The respective capacitive electrodes of the transmitter 210 and the receiver 220 are in optimal alignment when the central axes perpendicular to both respective capacitive electrodes are collinear.

[0138] Although the described alignment device has been described with respect to high frequency wireless power transfer, one skilled in the art will recognize that other alignment devices may be used in other wireless power systems, hi another embodiment, the described alignment device is configured for use in a non-high frequency wireless power system.

[0139] Additionally, those skilled in the art will recognize that while the disclosed exemplary alignment device 300 is designed for use with a high frequency inductive wireless power transfer system 200, the same concepts may be applied to create an alignment device 300 that will power other wireless power transfer systems 200, such as, but not limited to, a non-resonant magnetic induction system, a resonant magnetic induction system, a non-resonant electrocapacitive system, a resonant electrocapacitive system, a low frequency magnetic induction or electrocapacitive system.

[0140] Those skilled in the art will appreciate that further variations and modifications can be made without departing from the scope of the appended claims. [Explanation of symbols]

[0141] 100 Wireless power transfer system 110, 210 Transmitter 112 Power supply 114 Sending elements 120, 220 Receiver 122 Load 124 Receiving elements 200 High Frequency Wireless Power Transfer System 212 Transmitter coil 222 Receiver coil 230 Material 300, 700, 800, 1000, 1300 Alignment Device 310, 710, 810, 910, 954, 1010, 1310 Field Detection Unit (FDU) 312, 712, 812, 912, 956, 1012 coils 314, 714, 814, 1014 Tuning Capacitors 316, 716, 816, 1016, 1316 rectifier 318, 1318 main board 320, 1320 voltage divider 322, 822 comparator circuit 323, 823, 1323 Sensitivity control section 324, 824, 1324 indicators 750, 1050 Control / Logic Module 902, 904, 906, 920, 932, 958, 960, 962, 968 Capacitors 916(D3), 918(D2), 930(D1), 964, 966 Diodes 922, 944, 946, 970, 976 resistor 940, 942 Choke Inductors 950, 952, 980 Voltage Source 972, 974 Transistors 1060 Aligned Spots 1064 Outer region (low proximity) 1062 Inner Area (Medium Close) 1100 Spot 1102 Wire bundle 1104 Metal Mesh 1326 Analog / Digital (A / D) Converter 1328 Microcontroller

Claims

1. a coil configured to generate an induced voltage from a magnetic field or an electrode configured to generate an induced voltage from an electric field; a comparator configured to compare the induced voltage to a threshold voltage and activate an indicator based on the comparison; Equipped with the coil or the electrode forms part of a field sensing unit (FDU); The alignment device, wherein the FDU comprises at least one diode configured to add capacitance to the coil to reduce a resonant frequency of the coil.

2. The alignment device of claim 1 , wherein the induced voltage is proportional to the strength of a magnetic field across the coil or an electric field across the electrode.

3. 3. The alignment device of claim 1 or 2, configured to align a transmitter and a receiver for optimal power transfer efficiency.

4. 3. The alignment device of claim 1 or 2, configured to align a transmitter coil and a receiver coil for optimal power transfer efficiency.

5. The alignment device of claim 1 or 2, configured for use with a high frequency wireless power transfer system.

6. The alignment device of claim 1 , wherein the FDU comprises at least one tuning capacitor configured to tune the coil.

7. The alignment device of claim 6 , wherein the FDU comprises a rectifier configured to rectify the induced voltage from alternating current (AC) to direct current (DC).

8. The alignment device of claim 1 , comprising a plurality of FDUs, each FDU comprising an individual coil configured to generate an induced voltage from a magnetic field or an individual electrode configured to generate an induced voltage from an electric field.

9. The alignment device of claim 8 comprising four FDUs positioned orthogonally to one another in a plane.

10. The alignment device of claim 9 , wherein the FDUs are positioned equidistant from one another in the plane.

11. The alignment device of claim 8 comprising five FDUs positioned orthogonally to one another in a plane.

12. The alignment device of claim 11 , wherein four FDUs are positioned equidistant from a central FDU in the plane.

13. The alignment device of claim 1 or 2, wherein each FDU is associated with an individual indicator.

14. The alignment device of claim 1 , wherein the comparator forms part of a main board.

15. The alignment device of claim 14 , wherein the main board further comprises the indicator.

16. The alignment device of claim 14 , wherein the main board further comprises a voltage divider configured to scale down a voltage.

17. The alignment device of claim 14 , wherein the main board further comprises a sensitivity control configured to control the threshold voltage.

18. The alignment device of claim 1 or 2, further comprising a spirit level.

19. a) activating a transmitter positioned on one side of the material; b) positioning an alignment device on the other side of the material opposite the transmitter; c) generating an induced voltage from a magnetic field generated by the transmitter via a coil of the alignment device or generating an induced voltage from an electric field generated by the transmitter via an electrode of the alignment device, the coil or the electrode forming part of a field detection unit (FDU), the FDU comprising at least one diode configured to add a capacitance to the coil to reduce the resonant frequency of the coil; d) activating an indicator of the alignment device based on a comparison of the induced voltage to a threshold voltage; e) repositioning said alignment device relative to said transmitter; f) repeating steps c) to e) until optimal power transfer efficiency between said transmitter and said alignment device is obtained; The method includes:

20. 20. The method of claim 19, further comprising positioning a receiver at a location for optimal power transfer efficiency between the transmitter and the alignment device.

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