Apparatus and related methods for detecting magnetic flux field characteristics using a wireless power transmitter

Abstract

A wireless power transmitter may include: a transmitting coil configured to generate a wireless power signal for wireless power transmission; at least one secondary sensing coil configured to generate a signal in response to a magnetic flux field generated during the wireless power transmission; and control logic configured to detect at least one condition of the wireless power transmission system in response to detecting a distortion in the magnetic flux field according to at least one signal received from the secondary sensing coil. A related method may include: generating a wireless power signal using a wireless power transmitter; generating one or more signals using a plurality of secondary sensing coils in response to a magnetic flux field generated during the wireless power transmission; and detecting at least one condition of the wireless power transmission system in response to the one or more signals generated by the plurality of secondary sensing coils.

Description

[0001] This application is a divisional application of the Chinese invention patent application "Device and related method for detecting magnetic flux field characteristics using a wireless power transmitter" with an application date of January 22, 2016 and application number 201680017798.8.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application is related to U.S. Patent Application No. 14 / 603,275 (Attorney Docket No. 70107.471US01 (2976-UT)), filed on the same date as the present application, entitled “APPARATUSES AND RELATED METHODS FOR DETECTING MAGNETIC FLUX FIELD CHARACTERISTICS WITH A WIRELESS POWER RECEIVER,” the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0004] Embodiments of the present disclosure relate generally to wireless power transfer and, more particularly, to apparatus and related methods for detecting magnetic flux field characteristics during wireless power transfer. Background Art

[0005] Battery-powered devices (e.g., consumer electronic devices, electric and hybrid vehicles, etc.) are charged from a power source (e.g., an AC power outlet) via a charging device. The charging device couples the battery to the power source via an adapter. The cables extending between the power source and the battery-powered device may take up space. In the case where multiple devices need to be charged, each device has its own charger and cable, and the charging area may become cramped and inconvenient.

[0006] Methods of using radio or wireless power transmission between a transmitter and a receiver coupled to an electronic device are being developed. Wireless power transmission using an induction coil is considered to be an unrestricted method for wirelessly transmitting power through a coupled wireless power signal. In wireless power transmission, power is transmitted by sending a wireless power signal via a transmitting coil. On the receiver side, the receiving coil can be coupled to the transmitting coil by the wireless power signal, thereby wirelessly receiving the transmitted power. The distance between the transmitter coil and the receiving coil at which effective power transfer can occur is a function of the transmission energy, distance and alignment of the power transmission coil. The coupling coefficient (k) is a function of the distance and alignment between the coils, the coil size and the material. If the size of the coil is adjusted and operated at a frequency that causes the coils to be physically located within the so-called "near field region" to each other, the power conversion efficiency (e.g., coupling factor, coupling quality) can be significantly improved.

[0007] Problems encountered during wireless power transfers include situations where the transmitter and receiver are weakly coupled, which may occur due to misalignment of the transmitter and receiver, the presence of foreign objects, or other reasons. These problems may result in lower efficiency in wireless power transfer, which may also result in excess heat. Traditional foreign object detection methods may rely on coil temperature measurements (coils tend to get hot when foreign objects are present), or compare input power to output power to determine whether the output power is within the expected efficiency threshold (e.g., 350mW). These methods may fail because efficiency estimates may be unreliable for some typical operating conditions, which may result in detection errors. Summary of the invention

[0008] Embodiments of the present disclosure include a wireless power-enabled device including a wireless power transmitter. The wireless power transmitter includes: a transmitting coil configured to generate a wireless power signal for wireless power transmission to a wireless power receiver; at least one secondary sensing coil configured to generate a signal in response to a magnetic flux field generated during the wireless power transmission; and control logic operably coupled to the at least one secondary sensing coil. The control logic is configured to: detect at least one condition of the wireless power transmission system in response to detecting a distortion in the magnetic flux field based on at least one signal received from the secondary sensing coil.

[0009] Another embodiment of the present disclosure includes a wireless power-enabled device including a wireless power transmitter. The wireless power transmitter includes: a transmitting coil configured to generate a wireless power signal based on an input signal; a plurality of secondary sensing coils located near the transmitting coil; and control logic operably coupled to the plurality of secondary sensing coils. Each secondary sensing coil is configured to generate a signal of a magnetic flux field generated during wireless power transfer to a wireless power receiver. The control logic is configured to detect at least one condition of the wireless power transfer system based at least in part on a measured combination of inputs of signals generated from the plurality of secondary signals.

[0010] Another embodiment of the present disclosure includes a method for detecting a condition of a wireless power transmission system. The method includes: using a wireless power transmitter to generate a wireless power signal for wireless power transmission to a wireless power receiver; using a plurality of secondary sensing coils to generate one or more signals in response to a magnetic flux field generated during the wireless power transmission; and detecting at least one condition of the wireless power transmission system in response to the one or more signals generated by the plurality of secondary sensing coils. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic block diagram of a wireless power transmission system.

[0012] Figure 2is a schematic block diagram of a wireless power transmission system.

[0013] Figure 3 is a schematic diagram of a wireless power transmitter with a secondary sensing coil.

[0014] Figure 4 is a schematic diagram of a wireless power transmitter with a secondary sensing coil.

[0015] Figure 5 is a schematic diagram of a wireless power transmitter with a secondary sensing coil.

[0016] Figure 6 , Figure 7 and Figure 8 is a graph showing the output from the secondary sensing coil in response to various conditions of the wireless power transfer system. DETAILED DESCRIPTION

[0017] In the following description, reference is made to the accompanying drawings which illustrate specific embodiments of the present disclosure by way of illustration. Other embodiments may be used and may be changed without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be understood in a limiting sense, and the scope of the present invention is limited only by the appended claims.

[0018] Furthermore, unless otherwise indicated herein, the specific embodiments shown and described are merely examples and should not be interpreted as the only way to implement or distinguish the present disclosure as functional elements. It will be apparent to those skilled in the art that the various embodiments of the present disclosure can be implemented by many other partitioning solutions.

[0019] In the following description, elements, circuits, and functions may be shown in block diagram form in order not to confuse the present disclosure with unnecessary details. In addition, the block definitions and logical partitions between different blocks are exemplary specific implementations. It will be apparent to those of ordinary skill in the art that the present disclosure can be implemented by many other partition solutions. It will be understood by those of ordinary skill in the art that information and signals can be represented using any of a variety of different techniques and methods. Throughout the above, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or light particles, or any combination thereof. In order to represent and describe clearly, some drawings may show signals as single signals. It will be understood by those of ordinary skill in the art that a signal may represent a bus of a signal, wherein the bus may have different bit widths and the present disclosure may be implemented on any number of data signals (including a single data signal).

[0020] The various illustrative logic blocks, modules, and circuit modules described in conjunction with the embodiments disclosed herein may be implemented or executed by a general-purpose processor, a special-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a controller, a discrete gate or transistor logic unit, a discrete hardware component, or any combination thereof designed to perform the functions described herein. All of these may be referred to as "control logic".

[0021] A general purpose processor may be a microprocessor, but in the alternative, the general purpose processor may be any processor, controller, microcontroller, or state machine suitable for executing the processes of the present disclosure. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0022] A general purpose processor may be part of a general purpose computer, which should be considered a special purpose computer when configured to execute instructions (e.g., software code) for performing embodiments of the present disclosure. In addition, when configured according to embodiments of the present disclosure, such a special purpose computer improves the functionality of a general purpose computer because, without the present disclosure, the general purpose computer would not be able to perform the processes of the present disclosure. The present disclosure also provides meaningful limitations in one or more specific technical environments beyond the abstract concepts. For example, embodiments of the present disclosure provide improvements in the technical field of wireless power transmission, and more specifically, relate to devices and related methods for detecting magnetic flux field characteristics during wireless power transmission.

[0023] In addition, it is noted that the embodiments can be described in terms of a process, which can be described as a flow chart, a flow diagram, a structure diagram, or a block diagram. Although a process can describe the actions of an operation as a sequential process, many of these actions can be performed in another order, in parallel, or substantially simultaneously. In addition, the order of the actions can be reset. A process can correspond to a method, a function, a process, a subroutine, a subprogram, etc. In addition, the method disclosed herein can be implemented in hardware, software, or a combination of the two. If implemented in software, a function can be stored or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media includes both computer storage media and communication media, including any medium that is conducive to transmitting a computer program from one place to another.

[0024] It should be understood that any reference to an element using designations such as "first", "second" etc. herein is not to limit the quantity or order of these elements, unless these restrictions are clearly stated. On the contrary, these designations herein can be used as a practical method for distinguishing between two or more elements or element examples. Therefore, citing the first and second elements does not mean that only two elements can be adopted or that the first element must precede the second element in a certain way. In addition, unless otherwise stated, a group of elements can include one or more elements.

[0025] It should be recognized that the devices of the wireless power transmission system described herein are primarily directed to the functionality of wireless power transmission; however, it should be recognized that the wireless power transmission system may include additional components to perform other features not specifically described herein or not shown in the various figures. For example, the wireless power support device may include a communication module, an I / O module for interfacing with a user, a memory for storing instructions and data, various sensors, processors, controllers, and voltage regulators, among other components. Therefore, the drawings and accompanying descriptions may be slightly simplified to focus on various devices and methods configured to provide wireless power transmission and detect characteristics of magnetic flux fields and conditions of wireless power transmission systems.

[0026] Figure 1 is a schematic block diagram of a wireless power transmission system 100. The wireless power transmission system 100 includes a wireless power transmitting device 110 and a wireless power receiving device 120. The wireless power transmitting device 110 includes a wireless power transmitter 112 having a transmitting coil 114 configured to generate a wireless power signal 105 (e.g., an electric field, a magnetic field, an electromagnetic field, etc.) to provide power transmission to the wireless power receiving device 120 (e.g., via inductive coupling). The wireless power receiving device 120 includes a wireless power receiver 122 having a receiving coil 124 configured to couple with the wireless power signal 105. The sizes of the transmitting coil 114 and the receiving coil 124 can be adjusted according to the specific device and application associated therewith.

[0027] The input signal 116 may be provided to the wireless power transmitter 112 to generate the wireless power signal 105 that provides a power transfer to the wireless power receiving device 120. The wireless power receiver 122 may be coupled to the wireless power signal 105 and may generate an output signal 126 in response to the wireless power signal 105. The output signal 126 may provide power for storage (e.g., charging a battery), consumption (e.g., providing system power), or a combination thereof by the wireless power receiving device 120.

[0028] The wireless power transmitter 112 and the wireless power receiver 122 are separated by a certain distance (d). In some embodiments, the wireless power transmitter 112 and the wireless power receiver 122 may be configured according to a mutual inductance relationship so that when the resonant frequency of the wireless power receiver 122 and the resonant frequency of the wireless power transmitter 112 are substantially the same, the transmission loss between the wireless power transmitter 112 and the wireless power receiver 122 is minimized. Similarly, the wireless power transmitter 112 may set the frequency of the wireless power signal 105 at or near the resonant frequency of the coils 114, 124. As a result, efficient power transmission may be performed by coupling most of the energy in the near field of the transmitting coil 114 to the receiving coil 124 instead of propagating most of the energy to the far field as electromagnetic waves. If the wireless power receiving device 120 is in the near field (within a certain distance (d)), inductive coupling may be performed between the transmitting coil 114 and the receiving coil 124. The area surrounding the transmitting coil 114 and the receiving coil 124 where this near-field inductive coupling may be performed may be referred to as a "coupling area". Due to this mutual inductance relationship, wireless power transfer may be referred to as inductive wireless power transfer.

[0029] The transmitting coil 114 and the receiving coil 124 can be configured as a "loop" antenna, which may also be referred to herein as a "magnetic" antenna or an "inductive" antenna. The loop antenna can be configured to include an air core or a physical core (e.g., a ferrite core). The air core loop antenna is more tolerant to extraneous physical devices placed near the core. In addition, the air core loop antenna allows other components (e.g., a secondary sensing coil) to be placed within the core area. In addition, the air core loop can more easily enable the receiving coil 124 to be placed within the plane of the transmitting coil 114, where the coupling area of ​​the transmitting coil 114 can be stronger.

[0030] The wireless power receiving device 120 may be a mobile electronic device capable of receiving the wireless power signal 105, such as a cellular phone, a smart phone, a media player (e.g., an MP3 player, a DVD player, etc.), an e-reader, a tablet computer, a personal digital assistant (PDA), a camera, a laptop computer, and a personal electronic device. The wireless power receiving device 120 may also be a smaller mobile electronic device, such as a television, a personal computer, a media player (e.g., a DVD player, a Blu-ray player, etc.), or any other device that can be operated by and / or store power. The wireless power receiving device 120 may be one of a number of other items: for example, a car or any other device that may include a battery that can be charged by the wireless power transmitting device 110.

[0031] The wireless power transmitting device 110 may be a device that may also sometimes be a receiver of wireless power transmission. In other words, some devices may be configured to be both a wireless power transmitting device 110 and a wireless power receiving device 120, so that the device can send wireless power or receive wireless power based on the operating mode. Therefore, embodiments of the present disclosure include devices that may include a wireless charging transceiver that is configured to operate in a transmitting mode or in a receiving mode. The use of the term "receiver" indicates that the device is configured to receive wireless power transmission, but should not be interpreted as meaning that the device operates only as a receiver. Similarly, the use of the term "transmitter" indicates that the device is configured to send wireless power, but should not be interpreted as meaning that the device operates only as a transmitter.

[0032] In operation, a user may place the wireless power receiving device 120 near the wireless power transmitting device 110; however, the receiving coil 124 and the transmitting coil 114 may be misaligned. This misalignment may be caused by user error when the user places the wireless power receiving device 120. Misalignment is also often caused by movement of the wireless power receiving device 120 from its original position by other forces (e.g., the wireless power receiving device 120 may be hit, moved due to vibration, etc.).

[0033] Regardless of the cause of the misalignment, it is desirable for the wireless power transmitting device 110 to detect the misalignment because even a small mismatch between the receiving coil 124 and the transmitting coil 114 may reduce the efficiency of the wireless power transmission. Reduced efficiency may lead to undesirable problems such as wasted power, increased heat in the components, slower battery charging, etc. In addition to reduced efficiency, the accumulated energy of the fringe magnetic field due to misalignment may also cause problems. For example, if a user quickly moves the wireless power receiving device 120 so that the receiving coil 124 moves back into alignment with the transmitting coil 114, the sudden change from the accumulated energy may overwhelm (e.g., burn) the components of the wireless power receiving device 120. To prevent this, a conventional wireless power receiver may include a clamp capable of protecting its components; however, even with a clamp, in this case, a large amount of energy may still overwhelm and damage the wireless power receiver. Therefore, through embodiments of the present disclosure, it may also be desirable for the wireless power transmitting device 110 to detect misalignment.

[0034] Another problem that may occur during wireless power transmission includes the presence of foreign matter in the wireless charging field. The presence of foreign matter may also affect the efficiency of wireless power transmission, increase heat in the components of the wireless power transmission system 100 and in the foreign matter itself, etc. Therefore, through embodiments of the present disclosure, it may also be desirable for the wireless power transmitting device 110 to detect the presence of foreign matter.

[0035] Embodiments of the present disclosure include apparatus and methods for monitoring characteristics of a magnetic flux field of a wireless power transmission system 100. For example, the wireless power transmitter 112 may include a plurality of secondary sensing coils ( ) configured to detect a magnetic flux field near a transmitting coil 114. Figures 2 to 5 ). Specifically, the plurality of secondary sensing coils may generate signals in response to wireless power transmission; however, the signals may not be used for wireless power transmission to the wireless power receiving device 120. Instead, the signals may provide data to the wireless power transmitting device 110 that may be interpreted by the wireless power transmitting device 110 to detect misalignment, foreign objects, and other conditions that may affect the magnetic flux field during wireless power transmission. Figures 2 to 5 The configuration and operation of the secondary sensing coil is discussed in more detail.

[0036] In response to detecting the misalignment, the user may be notified and / or assisted in obtaining a strict alignment of the receiving coil 124 and the transmitting coil 114. The wireless power transmitter 112 may also be configured to take additional appropriate measures (e.g., reducing the transmission power, shutting down the power supply, etc.) during the misalignment situation to reduce the accumulated energy, which may protect the components of the wireless power receiving device 120 in the event of a sudden adjustment. The wireless power transmitting device 110 may also be configured to transmit the misalignment information to the wireless power receiving device 120, which may also assist in notifying the user and / or performing appropriate measures to protect itself from the misalignment problem.

[0037] In addition, the user may be notified of the presence of a foreign object so that the user can remove the foreign object from the wireless charging field. The wireless power transmitter 112 may also be configured to take additional appropriate measures (e.g., reduce the transmission power, turn off the power, etc.) in response to detecting the presence of a foreign object. The wireless power transmitting device 110 may also be configured to transmit the foreign object information to the wireless power receiving device 120, which may also assist in notifying the user and / or performing appropriate measures to protect itself from misalignment issues.

[0038] Figure 2 2 is a schematic block diagram of a wireless power transmission system 200 according to an embodiment of the present disclosure. The wireless power transmission system 200 includes a wireless power transmitter 212 and a wireless power receiver 222. The wireless power transmitter 212 and the wireless power receiver 222 can be configured to be coupled to each other according to a mutual inductance relationship so that the wireless power signal 105 ( Figure 1 ) can be transmitted from the wireless power transmitter 212 to the wireless power receiver 222.

[0039] The wireless power transmitter 212 may include a resonant tank 213, a bridge inverter 217, and a transmitter control logic 218 coupled together to generate a wireless power signal 105 that is sent to the wireless power receiver 222. The resonant tank 213 may include a transmitting coil 214 coupled to a resonant capacitor 215. The bridge inverter 217 of the wireless power transmitter 212 may include a full-bridge inverter, a half-bridge inverter, or other suitable circuit for receiving a DC input signal 216 and generating an AC signal that flows through the transmitting coil 214 to generate the wireless power signal 105. The wireless power transmitter 212 may also include a secondary sensing coil 219 coupled to the transmitter control logic 218. The secondary sensing coil 219 may be configured to sense characteristics (e.g., density, amplitude, etc.) of magnetic flux field lines near the transmitting coil 214. Therefore, the secondary sensing coil 219 may be passively coupled to the transmitter control logic 218 to provide the transmitter control logic 218 with data corresponding to the magnetic flux field present during wireless power transmission.

[0040] The wireless power receiver 222 includes a resonant tank 223, a rectifier 250, and a regulator 255 coupled together, and a control logic 280 to receive the wireless power signal 105 and generate an output signal (V OUT ). Output signal (V OUT ) may be provided to a load 270 (e.g., a battery, a system component, etc.), which may also have an output capacitor 260. The resonant tank 223 may include a receiving coil 224 coupled to the resonant capacitor 230. The wireless power transmitter 212 and the wireless power receiver 222 may be included in the wireless power transmitting device 110 ( Figure 1 ) and the wireless power receiving device 120 ( Figure 1 The sizes of the transmit coil 214 and the receive coil 224 (and other components) may be adjusted depending on the specific device and application with which they are associated.

[0041] Usually, the above Figure 1 The wireless power transmitter 212 and the wireless power receiver 222 are configured based on the discussion of FIG. The configuration of the LC networks within the resonant tanks 213, 223 can generally determine the resonant frequencies of the wireless power transmitter 212 and the wireless power receiver 222, respectively. For example, the resonant frequencies of the resonant tanks 213, 223 can be based on the inductance of their respective induction coils and the capacitance of the capacitor plates.

[0042] During wireless power transmission, an input signal 216 (DC signal) may be received by the bridge inverter 217. The bridge inverter 217 may generate an AC current that flows through the resonant tank 213 to generate a time-varying signal for transmitting the wireless power signal 105. Thus, the wireless power signal 105 may be a time-varying signal that is substantially sinusoidal, having a frequency that may be based on the switching frequency of the bridge inverter 217 of the wireless power transmitter 212. In some embodiments, the frequency of the wireless power signal 105 may be set according to a desired frequency, for example, a frequency for a particular wireless power standard. The resonant tank 213 may be configured such that the resonant frequency is approximately the frequency of the wireless power signal 105. In some embodiments, it may be desirable for the frequency of the wireless power signal 105 to be slightly different from the resonant frequency of the resonant tank 213 in order to reduce the peak-to-peak current flowing through the transmitting coil 214.

[0043] In order to receive the wireless power signal 105, the wireless power receiver 222 may be placed in the coupling region of the wireless power transmitter 212 so that inductive coupling may be achieved. As a result, the wireless power receiver 222 may receive the wireless power signal 105 and generate AC power in response to the received wireless power signal 105. In order for the load 270 to use the power, the AC power may be converted into DC power. The rectifier 250 may generate a rectified voltage (V RECT ) and the rectified current (I RECT In some embodiments, rectifier 250 may be configured as a synchronous rectifier. As a result, rectifier 250 may include one or more switches controlled in such a manner to generate a DC output power signal (ie, a rectified voltage (V RECT ) and the rectified current (I RECT )). In some embodiments, the rectifier 250 may include one or more diodes configured to generate a DC output power signal.

[0044] The regulator 255 can receive the rectified voltage (V RECT ) and converts the rectified voltage to have an output voltage (V OUT ) to a desired voltage level. For example, in some embodiments, the regulator 255 may RECT ) from low voltage to output voltage (V OUT ) is a relatively high voltage. In some embodiments, the regulator 255 can RECT ) from high voltage to output voltage (V OUT ) is a relatively low voltage. In some embodiments, the regulator 255 can RECT) from a positive voltage to a negative voltage, and vice versa. The regulator 255 can be configured according to one of a variety of different voltage regulator topologies. For example, the regulator 255 can be configured according to one or more of a buck topology, a boost topology, a buck-boost topology, an inverting topology, and a low dropout (LDO) topology. In some embodiments, the regulator 255 can be configured according to a transformer-based topology (e.g., forward, flyback, etc.). The operation of the regulator 255 can be controlled by the control logic 280 according to the topology used.

[0045] The control logic 280 of the wireless power receiver 222 may be configured to control one or more operations of the wireless power receiver 222. The control logic 218, 280 may be implemented within a processor (e.g., a microprocessor) or within other circuits configured (e.g., programmed) to perform various operations of the embodiments of the present disclosure. Each of the control logics 218, 280 may also include a computer-readable medium (e.g., a memory) that stores computational instructions executed by the processor associated with the execution process of the embodiments of the present disclosure. The memory may include volatile and non-volatile memory. In addition, each of the control logics 218, 280 may also control other functions of the corresponding wireless power transmitter 212, wireless power receiver 222, such as control related to foreign object detection, device operation, etc. The control logics 218, 280 may each include different sub-blocks that perform one or more of the above functions separately, rather than by adopting one or more of the above functions within a single process, routine, program, etc. In addition, the control logics 218, 280 may each use different hardware elements for different functions.

[0046] The most efficient power transfer can occur when the receiving coil 224 and the transmitting coil 214 are aligned, that is, when the receiving coil 224 is directly above the transmitting coil 214. When aligned, the magnetic flux field can be relatively symmetrical about the transmitting coil 214, and the efficiency of the power transfer can be substantially close to its peak. As the receiving coil 224 moves away from the alignment with the transmitting coil 214, the efficiency of the wireless power transmission can decrease. In addition, the magnetic flux field may become distorted (e.g., asymmetric) relative to its state when aligned. For example, if the receiving coil 224 moves away from the center, the magnetic flux field may also move toward the receiving coil 224 to concentrate in the area around the receiving coil 224. Note that for the purposes of this disclosure, when discussing the movement of the transmitter 212 and its components or the receiver 222 and its components, the movement is relative to each other. It should be recognized that some wireless power transmitters 212 may be relatively stationary or even built into stationary objects. In this case, moving the wireless power transmitter 212 or its components may mean physically moving the wireless power receiver 222. Although less common, in this case, some wireless power receivers 222 may be relatively stationary and the wireless power transmitter 212 may be physically moving.

[0047] The presence of foreign matter may also distort the magnetic flux field and reduce the efficiency of wireless power transfer. For example, the magnetic flux field may be concentrated in the area around the foreign object. As discussed herein, the secondary sensing coil 219 can be configured to sense the characteristics (e.g., density, amplitude, etc.) of the magnetic flux field lines near the transmitting coil 214. Such data can be particularly useful for detecting misalignment of the transmitting coil 214 and the receiving coil 224, detecting the presence of foreign matter, and the like.

[0048] Figure 3 is a schematic diagram of a wireless power transmitter 300 having secondary sensing coils 219A, 219B, 219C, 219D according to an embodiment of the present disclosure. As described above, the secondary sensing coils 219A, 219B, 219C, 219D are coupled to the transmitter control logic 218 and can be configured to sample the magnetic flux field near the transmitting coil 214. Therefore, the secondary sensing coils 219A, 219B, 219C, 219D can be located near the transmitting coil 214 to sense the characteristics (e.g., density, amplitude, etc.) of the magnetic flux field lines around the transmitting coil 214. Figure 3 As shown, the transmitting coil 214 can be generally circular. Other geometric shapes of the transmitting coil 214 are also contemplated, including but not limited to rectangular, triangular, etc. The secondary sensing coils 219A, 219B, 219C, 219D can also have various geometric shapes as desired.

[0049] Regarding the wireless power transmitter 212 ( Figure 2) can be used to determine how the wireless power transmitter 212 drives the magnetic flux field and identify different conditions of the wireless power transfer system 100. For example, the electrical measurements can be interpreted to determine that the transmit coil 214 and the receive coil 224 are aligned (or misaligned), there is a foreign object, etc. The wireless power transmitter 212 can identify such a condition by detecting distortion in the magnetic flux field according to the information sampled by the secondary sensing coils 219A, 219B, 219C, 219D.

[0050] The secondary sensing coils 219A, 219B, 219C, 219D may be located at positions that provide sampling points along the X-axis and the Y-axis, with the origin approximately being the center of the transmitting coil 214. For example, the first secondary sensing coil 219A is located at the +Y position, the second secondary sensing coil 219B is located at the -Y position, the third secondary sensing coil 219C is located at the +X position, and the fourth secondary sensing coil 219D is located at the -X position. Of course, it is contemplated that embodiments may include more or less than four secondary sensing coils. In general, increasing the number of secondary sensing coils that are part of the system provides a better characterization of the magnetic flux field, which may enable the transmitter control logic 218 to identify more anomalies of the expected magnetic flux field, as will be discussed in further detail below. In addition, it is contemplated that the secondary sensing coils 219A, 219B, 219C, 219D may be located at positions that are not along the X-axis or the Y-axis.

[0051] like Figure 3 As shown, each secondary sensing coil 219A, 219B, 219C, 219D can be independently coupled to the transmitter control logic 218. In other words, the transmitter control logic 218 can have a separate input pin coupled to each of the secondary sensing coils 219A, 219B, 219C, 219D. As a result, Figure 3 The four secondary sensing coils 219A, 219B, 219C, 219D can produce four independent measurements of the magnetic flux field sensed at each location.

[0052] In operation, the wireless power transmitter 212 may utilize the secondary sensing coils 219A, 219B, 219C, 219D to sense the magnetic flux field. Specifically, when the magnetic flux field is present during wireless power transmission, the secondary sensing coils 219A, 219B, 219C, 219D may generate a signal by induction. The signal may be used to provide the wireless power receiving device 120 ( Figure 1) The voltage signal is unrelated to the actual wireless power transmission for charging and / or providing power. The signals from the secondary sensing coils 219A, 219B, 219C, 219D can be received and processed by the transmitter control logic 218. The processing can be analog or digital signal processing. The transmitter control logic 218 can sample the signal according to the desired sampling rate (e.g., 200kHz) and analyze the sampled signal.

[0053] The transmitter control logic 218 may also interpret the sampled information (e.g., voltage measurements) to identify one or more conditions that affect the wireless power transfer system 100, such as alignment or misalignment of the transmit coil 214 and the receive coil 224, the presence of foreign objects, etc. For example, the transmitter control logic 218 may compare the sampled information to a reference measurement to determine if there are any distortions in the magnetic flux field and identify what conditions are causing the magnetic flux field to be distorted.

[0054] To simplify the description, measurements may be referred to in terms of levels relative to their alignment states. In other words, a value of "1" may be used to indicate the level of a signal sampled by a corresponding secondary sensing coil 219A, 219B, 219C, 219D when the transmitting coil 214 and the receiving coil 224 are in their alignment states, even though the actual measured voltage may be some other value (e.g., 3V). For example, in the aligned state, four measurements of the secondary sensing coils 219A, 219B, 219C, 219D may be 1, 1, 1, 1 for the +Y, -Y, +X, -X positions, respectively. Another set of measurements may produce 0, 2, 1, 1, which may indicate that the transmitting coil 114 and the receiving coil 224 are not aligned in the -Y direction. Note that some embodiments may include some secondary sensing coils 219A, 219B, 219C, 219D that are wound in reverse, so that some signals may have opposite polarities (e.g., 1, -1, 1, -1).

[0055] Various possible combinations for misalignment may be stored as reference measurement combinations in a memory of the transmitter control logic 218. For example, a first reference measurement combination of inputs may be stored for a misalignment of 1 mm in the +X direction, a second reference measurement combination of inputs may be stored for a misalignment of 1 mm in the -X direction, a third reference measurement combination of inputs may be stored for a misalignment of 2 mm in the +X direction, and so on (e.g., 11 mm in the +X direction). Similarly, multiple reference measurement combinations of inputs may be stored for misalignment in the ±Y directions. In addition, multiple reference measurement combinations of inputs may be stored for misalignment in both the X and Y directions (e.g., 1 mm+X and 3 mm-Y, 4 mm-X and 7 mm+Y, etc.). Each of these reference measurement combinations may include a value for each input and be stored as a combination in a lookup table (e.g., in firmware).

[0056] Actual measurements during user operation may result in a combination of inputs that are compared to a reference measurement combination stored in the transmitter control logic 218 to determine misalignment, if any. For example, a measurement combination of 3, 1, 3, 1 may be compared to a reference measurement combination to determine that the receive coil 224 is misaligned in both the +X and +Y directions. It should be noted that the combinations and corresponding misalignment amounts are provided herein only as examples, and that the reference measurement combination may depend, among other factors, on the operating point of the coil, the physical characteristics of the coil, etc. Other measurement combinations may provide information about other conditions. As a result, additional reference measurement combinations may be stored in the lookup table to detect these additional conditions. Thus, the lookup table may also include reference measurement combinations that provide models of ideal characteristics of the magnetic flux field that should be present under different conditions in order to have valid data.

[0057] In some cases (e.g., the presence of foreign matter), the combination from the actual measurement may not match any stored reference measurement combination. For example, for the +Y, -Y, +X, -X positions, the actual measurement combination may be 1, 1, 6, 1, respectively. Such a combination may not match any stored reference measurement combination, which may indicate to the transmitter control logic 218 that a problem has occurred that is not recognized as valid data (e.g., the presence of foreign matter). In other words, the measurement may be distinguished from the reference measurement combination in a manner that is not recognized by the transmitter control logic 218. The difference may indicate that the distortion in the magnetic flux field is attributable to problems such as foreign matter that are not simply misaligned. Therefore, the determination of foreign object detection may be based at least in part on identifying alignment. For example, if there is a known combination for alignment, the distortion is also unlikely to be caused by foreign matter, and false triggers for foreign matter may be reduced.

[0058] The transmitter control logic 218 may also be configured to assist in corrective measures for these conditions. For example, to assist in correcting misalignment, the wireless power transmitting device 110 ( Figure 1 ) and / or the wireless power receiving device 120 ( Figure 1 ) can notify the user of the misalignment. The notification may include a visual notification (e.g., an image displayed on a graphical user interface, a lighted LED for indicating a direction, etc.), an audible notification (e.g., a beep, a voice command, an alarm, etc.), a tactile notification (e.g., a vibration), etc., and combinations thereof. The notification may also assist the user in how to correct the misalignment. For example, the user may be notified in which direction the receiving coil 224 and / or the transmitting coil 214 should be moved to achieve alignment. As a result, the user can correct the misalignment of the transmitting coil 214 and the receiving coil 224 to improve the efficiency of the wireless power transmission system 100.

[0059] Another corrective measure may include the wireless power transmitter 112 reducing power transmission. In some embodiments, reducing power transmission may include shutting off power transmission completely. Reducing power transmission may be a desired remedy for conditions that may cause damage to different components of the wireless power transmission system 100. As described above, if the misaligned transmitting coil 214 and receiving coil 224 are quickly moved into alignment, the wireless power receiver 122 may experience a current spike that may damage the components of the wireless power receiving device 120. In a conventional wireless power system, the current spike may not be distinguishable from other current spikes caused by the load. Some current spikes caused by alignment problems may be larger than the spikes caused by the load. As a result, the wireless power receiver 122 may not be prepared to handle such a larger current spike, which may cause component damage. Therefore, the power can be reduced so that the amount of energy accumulated in the fringe magnetic field is low enough so that the components of the wireless power receiving device 120 are not damaged when the user quickly moves the wireless power receiver 122 so that the transmitting coil 114 and the receiving coil 124 are closer to alignment. If the transmitter control logic 218 detects that the alignment has improved, the wireless power transmitter 112 can increase the power again to a more normal level because the risk of damage caused by jitter has been reduced. In some embodiments, if the transmitter control logic 218 detects a rapid decrease in misalignment, the wireless power transmitter 112 reduces (e.g., terminates) power transmission in response.

[0060] like Figure 3As shown, the secondary sensing coils 219A, 219B, 219C, 219D can be located near the ferrite shield 302 around the periphery of the transmitting coil 214; however, other locations are contemplated. For example, the secondary sensing coils 219A, 219B, 219C, 219D can be located just outside the ferrite shield 302, on the ferrite shield 302, on the transmitting coil 214, on or within the core of the transmitting coil 214, or at some other location within the magnetic flux field during wireless power transfer. The location, orientation, geometry, etc. of the secondary sensing coils 219A, 219B, 219C, 219D can increase / decrease gain, make manufacturing easier / harder, etc.

[0061] In some embodiments, each of the secondary sensing coils 219A, 219B, 219C, 219D may include a single loop coil. In some embodiments, each of the secondary sensing coils 219A, 219B, 219C, 219D may include a multi-loop coil. Some embodiments may include a combination of single loop coils and multi-loop coils for the secondary sensing coils 219A, 219B, 219C, 219D. The secondary sensing coils 219A, 219B, 219C, 219D may be formed by copper traces on a printed circuit board with the transmitting coil 214 and the transmitter control logic 218. In some embodiments, each of the secondary sensing coils 219A, 219B, 219C, 219D may be formed as an external wire coupled to the PCB, embedded within the PCB, or embedded on the transmitting coil 214.

[0062] Although Figure 3 Four secondary sensing coils 219A, 219B, 219C, 219D are shown in (and other figures), but more or fewer secondary sensing coils may be used depending on the desired number of measurements and the locations of the measurements. In general, the more secondary sensing coils used, the better the sampling points that can be received to obtain a better understanding of the magnetic flux field. In addition, the secondary sensing coils 219A, 219B, 219C, 219D may be routed in at least one turn in some embodiments and may be routed in more than one turn in some embodiments (depending on the stray magnetic flux used to find the required voltage). In some embodiments, the secondary sensing coils 219A, 219B, 219C, 219D may be located in the same 2D plane as the transmitting coil 214. In some embodiments, one or more secondary sensing coils 219A, 219B, 219C, 219D may be located in another 2D plane. In other words, one or more of the secondary sensing coils 219A, 219B, 219C, 219D may be located in 3D space relative to the transmitting coil 214 .

[0063] In some embodiments, each of the secondary sensing coils 219A, 219B, 219C, 219D can be individually coupled as an input to the transmitter control logic 218 to provide independent measurements for each of the secondary sensing coils 219A, 219B, 219C, 219D. In some embodiments, one or more secondary sensing coils 219A, 219B, 219C, 219D can be coupled together to combine measurements in an additive or subtractive manner. Such a combination can include pairs of secondary sensing elements, and additional secondary sensing elements (i.e., three or more secondary sensing elements) can also be combined to provide different combinations of additive and / or subtractive measurements.

[0064] Figure 4 is a schematic diagram of a wireless power transmitter 400 having secondary sensing coils 219A, 219B, 219C, 219D according to an embodiment of the present disclosure. Figure 4 As shown, the secondary sensing coils 219A, 219B, 219C, 219D can be grouped into pairs, and the paired secondary sensing coils are coupled together to a common input pin of the transmitter control logic 218. For example, the secondary sensing coils 219A, 219B aligned in the y direction can be coupled to a first input pin of the transmitter control logic 218. Similarly, the secondary sensing coils 219C, 219D aligned in the x direction can be coupled to a second input pin. Each pair of secondary sensing coils 219A, 219B, 219C, 219D can be configured as additive or subtractive as desired.

[0065] In some embodiments, each pair of secondary sensing coils 219A, 219B, 219C, 219D can be wound in opposite directions. For example, the first secondary sensing coil 219A can be wound in opposite directions with the second secondary sensing coil 219B. Similarly, the third secondary sensing coil 219C can be wound in opposite directions with the fourth secondary sensing coil 219D.

[0066] If the pairs of secondary sensing coils 219A, 219B, 219C, 219D are configured to be subtractive, the signals from each pair can substantially cancel each other if the transmitting coil 214 and the receiving coil 224 are aligned due to the symmetrical nature of the magnetic flux field. For example, the first secondary sensing coil 219A and the second secondary sensing coil 219B can each generate a 2V signal, but in the case where the secondary sensing coils 219A, 219B are reversely wound so that the signals have opposite polarities, these signals can cancel each other. Similarly, the third secondary sensing coil 219C and the fourth secondary sensing coil 219D can each generate a 2V signal, but in the case where the secondary sensing coils 219C, 219D are reversely wound so that the signals have opposite polarities, these signals can cancel each other. Therefore, the inputs to the transmitter control logic 218 during wireless power transfer can each be approximately 0V, which can indicate that the transmitting coil 214 and the receiving coil 224 are aligned.

[0067] When the receiving coil 224 moves away from the aligned position in the +Y direction, the signal generated by the first secondary sensing coil 219A may increase, while the signal generated by the second secondary sensing coil 219B may decrease. As a result, the combined signal input to the transmitter control logic 218 may be a positive voltage. Similarly, when the receiving coil 224 moves away from the aligned position in the -Y direction, the signal generated by the second secondary sensing coil 219B may increase, while the signal generated by the first secondary sensing coil 219A may decrease. As a result, the combined signal input to the transmitter control logic 218 may be a negative voltage.

[0068] When the receiving coil 224 moves away from the aligned position in the +X direction, the signal generated by the third secondary sensing coil 219C may increase, while the signal generated by the fourth secondary sensing coil 219D may decrease. As a result, the combined signal input to the transmitter control logic 218 may be a positive voltage. Similarly, when the receiving coil 224 moves away from the aligned position in the -X direction, the signal generated by the fourth secondary sensing coil 219D may increase, while the signal generated by the third secondary sensing coil 219C may decrease. As a result, the combined signal input to the transmitter control logic 218 may be a negative voltage.

[0069] The above example describes the case where the paired secondary sensing coils 219A, 219B, 219C, 219D are configured to be subtractive. In some embodiments, the paired secondary sensing coils 219A, 219B, 219C, 219D can be configured to add signals. As a result, the input for the alignment state can be a non-zero value, and the input value can be changed from this value in response to the occurrence of misalignment.

[0070] Figure 5is a schematic diagram of a wireless power transmitter 500 having secondary sensing coils 219A, 219B, 219C, and 219D according to an embodiment of the present disclosure. Figure 5 As shown, the secondary sensing coils 219A, 219B, 219C, 219D can be located in the central region of the transmitting coil 214. The magnetic flux field can also be distorted in this region in response to conditions of the wireless power transfer system 100, where the conditions of the wireless power transfer system 100 can be detected by the secondary sensing coils 219A, 219B, 219C, 219D. The central region can be open to provide space for the secondary sensing coils 219A, 219B, 219C, 219D without increasing the thickness required for the secondary sensing coils 219A, 219B, 219C, 219D. In some embodiments, each of the secondary sensing coils 219A, 219B, 219C, 219D can be independently coupled to the transmitter control logic 218, as described above with respect to Figure 3 In some embodiments, at least some of the secondary sensing coils 219A, 219B, 219C, 219D may be coupled together to a common input terminal, as discussed above with respect to Figure 4 discussed.

[0071] In further embodiments, there may be more than one wireless power transmitter 112 and more than one wireless power receiver 122 within a single wireless power transfer system 100. As the number of wireless power transmitters 112 and the number of wireless power receivers 122 increase, the problem and combination may become more complex because the fringe fields from adjacent coils may affect each other.

[0072] Figure 6 , Figure 7 and Figure 8 Graphs 600, 700, 800 showing the output from the secondary sensing coil in response to various conditions of the wireless power transfer system. Each of these graphs shows three signals 602, 604, 606 generated by the secondary sensing coil at the +Y, -X and -Y positions, respectively. These signals 602, 604, 606 are also monitored as continuous AC signals from an oscilloscope. As described above, such signals 602, 604, 606 can be sampled by the transmitter control logic 218 and processed as digital signals. Finally, it should also be noted that the signals 602, 604, 606 are shown as independent signals; however, if desired, one or more signals can be coupled together (e.g., to reduce the number of input pins of the transmitter control logic 218).

[0073] Specific reference Figure 6, the graph 600 represents the alignment state of the transmitting coil 214 and the receiving coil 224. Specifically, the three signals 602, 604, 606 each have approximately the same peak value. Each of these peak (or RMS) values ​​can be regarded as a base value (referred to as a "1" value above) indicating alignment in that direction.

[0074] Specific reference Figure 7 , the graph 700 represents a misaligned state where the receive coil 224 has moved in the -X direction. As a result, the signal 604 associated with the -X direction increases.

[0075] Specific reference Figure 8 , the graph 800 represents various states in which the receiving coil 224 moves between different alignment states and misalignment states. Specifically, along the horizontal axis of the graph 800, "0" represents alignment, "+2y" represents a misalignment of 2 mm in the +Y direction, "-2y" represents a misalignment of 2 mm in the -Y direction, "+2x" represents a misalignment of 2 mm in the +X direction, and "-2x" represents a misalignment of 2 mm in the -X direction. The first half of the graph 800 shows a condition where no load is coupled to the wireless power receiver, and the second half of the graph 800 shows a condition where a 1A load is coupled to the wireless power receiver.

[0076] As shown in the graph 800, different signals 602, 604, 606 may change in response to the wireless power receiver being moved to different positions. As shown, moving the wireless power receiver in one direction may have some effect on all signals 602, 604, 606, not just the signals in that direction. Therefore, each of these signals 602, 604, 606 may be sampled at each position to obtain a reference combined measurement associated with a particular misalignment state.

[0077] Although the present disclosure has been described herein with respect to certain illustrative embodiments, those of ordinary skill in the art will recognize and appreciate that the present invention is not limited thereto. Rather, various additions, deletions, and modifications may be made to the illustrated and described embodiments without departing from the scope of the present disclosure. Furthermore, features from one embodiment may be combined with features of another embodiment contemplated by the inventors that is still within the scope of the present disclosure.

Claims

1. A device supporting wireless power, comprising: Wireless power transmitter, comprising: a transmitting coil configured to generate a wireless power signal according to an input signal; a plurality of secondary sensing coils located proximate to, adjacent to, coplanar with, and external to the transmitting coil, each secondary sensing coil being configured to generate a signal of a magnetic flux field generated during wireless power transfer to a wireless power receiver; and control logic operably coupled to the plurality of secondary sensing coils, the Control logic is configured to detect a misalignment between the transmit coil and the wireless power receiver based at least in part on a measured combination of inputs from signals generated by the plurality of secondary sensing coils.

2. The wireless power supporting device according to claim 1, wherein: The plurality of secondary sensing coils include: a first secondary sensing coil and a second secondary sensing coil along the y-axis and a third secondary sensing coil and a fourth secondary sensing coil along the x-axis, wherein: The first secondary sensing coil is located at the +Y position along the y-axis; The second secondary sensing coil is located at the -Y position along the y-axis; The third secondary sensing coil is located at the +X position along the x-axis; and The fourth secondary sensing coil is located at the -X position along the x-axis.

3. The wireless power supporting device according to claim 1, wherein: Each of the plurality of secondary sensing coils is configured as one of a single-loop coil and a multi-loop coil.

4. The wireless power supporting device according to claim 1, wherein: The control logic is also configured to detect the presence of a foreign object within the magnetic flux field.

5. The wireless power supporting device according to claim 1, wherein: The control logic is further configured to determine an amount of misalignment based at least in part on a comparison of the input measurement combination to a plurality of reference measurement combinations stored in a memory of the control logic.

6. The wireless power supporting device according to claim 4, wherein: The control logic is further configured to determine the presence of a foreign object based at least in part on a comparison of the input measurement combination with alignment information stored in a memory of the control logic.

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