Wireless power transmission apparatus with multiple primary coils and adjacent coil muting

Abstract

To provide a wireless power receiving apparatus and a method for wireless power transmission that improve the reliability and efficiency.SOLUTION: In a wireless power system 100, a wireless power transmission apparatus includes multiple primary coils 121-126 associated with zones 130, 150. Each zone has a local controller for managing operation of one primary coil in the zone at a time. A master controller selectively couples the primary coils to the local controllers. When one primary coil is coupled to the local controller for a zone, the master controller disables the other primary coils in the zone. The master controller manages which primary coils from neighboring zones are coupled to their respective local controllers. Thus, when a voltage is applied to the one primary coil, the adjacent primary coils can be muted or disabled to mitigate undesirable interference.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure generally relates to wireless power, and more specifically, to a wireless power transmission device.

Background Art

[0002] Conventional wireless power systems have been developed mainly for charging batteries in wireless power receiving devices such as mobile devices, small electronic devices, and gadgets. In a conventional wireless power system, a wireless power transmission device can include a primary coil that generates an electromagnetic field. The electromagnetic field can induce a voltage in a secondary coil of the wireless power receiving device when the secondary coil is placed close to the primary coil. In this configuration, the electromagnetic field can wirelessly transmit power to the secondary coil. Power can be transmitted using resonant coupling or non-resonant inductive coupling between the primary coil and the secondary coil. The wireless power receiving device may operate using the received power, or may store the received energy in a battery for later use. The power transmission capability can be related to how closely the primary coil and the secondary coil are placed relative to each other. Thus, in some conventional wireless power systems, the structure of the wireless power transmission device may be designed to limit the positioning of the wireless power receiving device and impose an expected alignment between the primary coil and the secondary coil.

Summary of the Invention

[0003] The systems, methods, and devices of the present disclosure each have several innovative aspects, and only one of which is not solely responsible for the desirable attributes disclosed herein.

[0004] One innovative aspect of the subject matter described in this disclosure can be implemented in a wireless power transmission device. In some implementations, the wireless power transmission device may include a plurality of primary coils organized into at least a first primary coil group and a second primary coil group. The wireless power transmission device may include at least a first local controller associated with the first primary coil group and a second local controller associated with the second primary coil group. A plurality of switches within the wireless power transmission device can individually couple the first local controller to one of the primary coils of the first primary coil group and individually couple the second local controller to one of the primary coils of the second primary coil group. The wireless power transmission device may include a master controller configured to operate a plurality of switches to control which primary coil of the first primary coil group is coupled to the first local controller and which primary coil of the second primary coil group is coupled to the second local controller.

[0005] In some implementations, the master controller may be configured to determine that a first primary coil among the plurality of primary coils is supplying wireless power to a first wireless power receiving device. The master controller can operate the plurality of switches to keep one or more adjacent primary coils near the first primary coil disconnected from their respective local controllers while the first primary coil is supplying wireless power to the first wireless power receiving device.

[0006] In some embodiments, the master controller may be configured to disable the first local controller before changing the states of the plurality of switches in order to control which primary coil among the first group of primary coils is coupled to the first local controller. Disabling the first local controller can prevent current from flowing from the first local controller through the plurality of switches while the states of the plurality of switches are being changed. After changing the states of the plurality of switches, the master controller may enable the first local controller to control which primary coil among the first group of primary coils is coupled to the first local controller.

[0007] In some embodiments, the plurality of switches includes a first set of switches configured to individually couple the first local controller to one primary coil among the first group of primary coils, and a second set of switches configured to individually couple the second local controller to one primary coil among the second group of primary coils.

[0008] In some embodiments, the wireless power transmission device may include a plurality of local controllers including at least a first local controller and a second local controller. The at least first local controller may include a communication unit capable of receiving communication from the first wireless power receiving device via the first primary coil when the first wireless power receiving device is close to the first primary coil and the first local controller is coupled to the first primary coil. The first local controller may further include a control unit configured to manage the operation of the driver in response to receiving the communication from the first wireless power receiving device. The first local controller may further include a driver configured to generate an electrical output to the first primary coil when the first primary coil is coupled to the first local controller via the plurality of switches.

[0009] In some implementations, the first local controller may be configured to determine a status signal to send to the master controller, and the status signal is at least partially based on communication from the first wireless power receiving device, the wireless power transmission status, the electrical output generated in the first primary coil, a fault status related to charging of the first wireless power receiving device, or any combination thereof. The first local controller may be configured to send the status signal to the master controller.

[0010] In some implementations, the master controller can be configured to determine, at least partially based on the status signal, that the first primary coil is not supplying wireless power to the first wireless power receiving device. The master controller can operate a plurality of switches to couple the first local controller to one or more other primary coils among the first primary coil group.

[0011] In some implementations, the master controller can be configured to determine, at least partially based on the status signal, that the first primary coil is supplying wireless power to the first wireless power receiving device. While the status signal indicates that the first primary coil is supplying wireless power to the first wireless power receiving device, the master controller can prevent the plurality of switches from disconnecting the first local controller from the first primary coil.

[0012] In some implementations, while the status signal indicates that the first primary coil is supplying wireless power to the first wireless power receiving device, the master controller may be configured to prevent the plurality of switches from coupling one or more adjacent primary coils near the first primary coil to their respective local controllers.

[0013] In some embodiments, the master controller may be configured to sequentially connect the primary coils in the first primary coil group to the first local controller via a plurality of switches. For each primary coil in the first primary coil group, the master controller may receive a status signal from the first local controller. The status signal may indicate whether the first local controller detects the first wireless power receiving device in the connected primary coil.

[0014] In some embodiments, the master controller may be configured to simultaneously connect the first primary coil in the first primary coil group to the first local controller and the second primary coil in the second primary coil group to the second local controller via a plurality of switches. The first primary coil and the second primary coil may not be adjacent to each other.

[0015] In some embodiments, the master controller may be configured to operate a plurality of switches such that each of the plurality of primary coils is connected to a respective local controller according to a pattern that prevents adjacent primary coils from being simultaneously connected.

[0016] In some embodiments, each primary coil group may include at least two primary coils that can be selectively connected to a local controller. Each primary coil group may be connected to the local controller of the group via at least one switch.

[0017] In some embodiments, the first primary coil group may include three primary coils that are selectively connected to the first local controller via two switches.

[0018] In some embodiments, the wireless power transmission device may include a charging pad on which a plurality of wireless power receiving devices can be placed. The plurality of primary coils may be arranged in a pattern that is dispersed and overlapped in a plurality of layers of the charging pad.

[0019] In some embodiments, at least one subset of the plurality of primary coils may be composed of graphene.

[0020] In some embodiments, when the first wireless power receiving device is close to the first primary coil and the first local controller is coupled to the first primary coil, at least the first primary coil among the first primary coil group is configured to transmit wireless power to the first wireless power receiving device in response to communication from the first wireless power receiving device via the first primary coil. When the second wireless power receiving device is close to the second primary coil and the second local controller is coupled to the second primary coil, at least the second primary coil among the second primary coil group is configured to transmit wireless power to the second wireless power receiving device in response to communication from the second wireless power receiving device via the second primary coil.

[0021] In some embodiments, the first primary coil and the second primary coil may not be adjacent to each other. The first primary coil and the second primary coil may be configured to simultaneously transmit wireless power to the first wireless power receiving device and the second wireless power receiving device, respectively.

[0022] In some embodiments, the plurality of switches may include a mechanical or solid-state relay that is a control switch having normally closed (NC) terminals and normally open (NO) terminals. The switching of the state between the NC terminals and the NO terminals is managed by the master controller.

[0023] Another innovative aspect of the subject matter described in this disclosure can be implemented as a method performed by a wireless power transmission device. In some implementations, the method may include managing the connections between a plurality of primary coils and their respective local controllers via a plurality of switches. The method may include determining that a first primary coil among the plurality of primary coils is supplying wireless power to a first wireless power receiving device. The method may include operating, by a master controller, the plurality of switches such that one or more adjacent primary coils near the first primary coil remain disconnected from their respective local controllers while the first primary coil is supplying wireless power to the first wireless power receiving device.

[0024] In some implementations, the plurality of primary coils can be organized into a first primary coil group that can be individually coupled to a first local controller via at least a first subset of the plurality of switches and a second primary coil group that can be individually coupled to a second local controller via a second subset of the plurality of switches.

[0025] In some implementations, the method may include disabling the first local controller before changing the states of the plurality of switches to control which primary coils of the first primary coil group are coupled to the first local controller. Disabling the first local controller prevents current from flowing from the first local controller through the plurality of switches while the states of the plurality of switches are being changed. The method may include enabling the first local controller after changing the states of the plurality of switches to control which primary coils of the first primary coil group are coupled to the first local controller.

[0026] In some embodiments, the method may include, when a first wireless power receiving device is close to a first primary coil and a first local controller is coupled to the first primary coil, receiving, by the first local controller, communication from the first wireless power receiving device via the first primary coil. The method may include determining, by the first local controller, a status signal to be transmitted to a master controller, where the status signal is based at least in part on communication from the first wireless power receiving device, a wireless power transmission state, electrical output generated in the first primary coil, a fault state related to charging of the first wireless power receiving device, or any combination thereof. The method may include transmitting the status signal from the first local controller to the master controller.

[0027] In some embodiments, the method may include determining, at least in part based on the status signal, that the first primary coil is not supplying wireless power to the first wireless power receiving device. The method may include operating a plurality of switches to couple the first local controller to one or more other primary coils of a first primary coil group.

[0028] In some embodiments, the method may include determining, at least in part based on the status signal, that the first primary coil is supplying wireless power to the first wireless power receiving device by the master controller. The method may include preventing, by the master controller, the plurality of switches from disconnecting the first local controller from the first primary coil while the status signal indicates that the first primary coil is supplying wireless power to the first wireless power receiving device.

[0029] In some implementations, while the status signal indicates that the first primary coil is supplying wireless power to the first wireless power receiving device, the method may include preventing a plurality of switches from coupling one or more adjacent primary coils near the first primary coil to respective local controllers.

[0030] In some implementations, the method may include sequentially coupling, by the plurality of switches, a primary coil of a first group of primary coils to a first local controller. The method may include receiving, from the first local controller, a status signal indicating whether the first local controller has detected the first wireless power receiving device in the coupled primary coil, for each primary coil of the first group of primary coils.

[0031] In some implementations, the method may include simultaneously coupling, by the plurality of switches, a first primary coil of a first group of primary coils to a first local controller and a second primary coil of a second group of primary coils to a second local controller. The first primary coil and the second primary coil may not be adjacent.

[0032] In some implementations, the method may include operating the plurality of switches to couple each of the plurality of primary coils to a respective local controller according to a pattern that prevents adjacent primary coils from being simultaneously coupled.

[0033] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will be apparent from the description, the drawings, and the claims. It should be noted that the relative dimensions in the following figures may not be drawn to scale.

Brief Description of the Drawings

[0034]

Figure 1

Figure 2A

Figure 2B

Figure 3

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Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0035] The following description is directed to particular implementations for the purpose of illustrating innovative aspects of the present disclosure. However, those skilled in the art will readily recognize that the teachings herein can be applied in many different ways. The described implementations can be implemented with any means, apparatus, system, or method for transmitting or receiving wireless power.

[0036] Conventional wireless power systems can include a wireless power transmission device and a wireless power reception device. The wireless power transmission device can include a primary coil that transmits wireless energy (as a wireless power signal) to a corresponding secondary coil within the wireless power reception device. The primary coil is the wireless energy source (such as inductive energy or magnetic resonance energy) of the wireless power transmission device. The secondary coil of the wireless power reception device receives the wireless energy. Wireless power transmission is more efficient when the primary coil and the secondary coil are disposed in proximity to each other. Conversely, if the primary coil and the secondary coil are misaligned, the efficiency may decrease (or power transmission may stop). Conventional wireless power transmission devices may include a controller that enables or disables the transmission of wireless energy based on how closely the wireless power reception device is disposed relative to the wireless power transmission device. For example, the transmission of wireless energy may depend on the degree of alignment between the power transmission coil and the power reception coil. In the present disclosure, alignment refers to the spatial relationship between the secondary coil of the wireless power reception device and the primary coil of the wireless power transmission device.

[0037] To address concerns about misalignment and increase positioning flexibility, some wireless power transfer devices may include multiple primary coils. For example, primary coils may be disposed on the charging surface of the wireless power transfer device. The primary coils may be configured in an overlapping arrangement or a non-overlapping arrangement. The arrangement (overlapping or non-overlapping) of the primary coils may be designed to minimize, reduce, or eliminate dead zones. Depending on the orientation and position of the wireless power receiving device on the charging surface, different primary coils may be energized to supply power to the corresponding secondary coil of the wireless power receiving device. Thus, the wireless power transfer device can support a degree of freedom in position such that the wireless power receiving device can be charged regardless of its position and orientation relative to the charging surface. Further, multiple wireless power receiving devices may be charged simultaneously using different primary coils of the wireless power transfer device. However, when the wireless power transfer device has multiple primary coils, unused primary coils may cause undesirable electromagnetic interference (EMI) to the nearby primary coils that are supplying wireless power to the wireless power receiving device.

[0038] According to the present disclosure, a wireless power transfer device may have multiple primary coils that can be selectively and individually coupled to a local controller. The local controller may include a communication function, a control function, a driver, or other power signal generation circuitry. In some implementations, the local controller (when connected to one of the primary coils) can implement wireless power transfer according to a standardized wireless power specification such as the Qi (registered trademark) specification provided by the Wireless Power Consortium. For example, the wireless power transfer device may include multiple primary coils, and each primary coil can be connected to the local controller to conform to the Qi specification.

[0039] In some implementations, the primary coils may be grouped into groups of primary coils that can be managed separately. A group of primary coils may sometimes be referred to as a zone in some aspects of the present disclosure. Each zone of the wireless power transfer device may have a separate zone circuit connectable to the primary coils within the zone so that each primary coil can be energized independently. For example, the zone circuit may include a local controller, a driver, a voltage regulator, a tank circuit capacitor, etc. common to all the primary coils associated with the zone. The zone circuit can be connected to different primary coils using one or more relays or switches. A relay is a type of switch. For example, the relay can be an electromechanical switch or a solid-state switch that can be controlled by a control signal. In some implementations, the relay may have a common terminal, a normally closed (NC) terminal, and a normally open (NO) terminal. When the control signal is not functioning (not energized), the internal switching mechanism of the relay may connect the common terminal and the NC terminal. When the control signal is functioning (energized), the internal switching mechanism may connect the common terminal and the NO terminal. In some implementations, the relay may be a packaged electrical component including a switch that is operated or stopped by a control signal. Thus, the terms relay, controllable switch, or switch may be used interchangeably herein. Although the examples of the present disclosure refer to relays for simplicity, it should be understood that other types of switches may be used to connect the zone circuit to the primary coils.

[0040] The connection between the primary coil and the local controller may be made via a relay (or other type of switch). Depending on the state of one or more relays, it may be determined which primary coil within the zone is connected to the zone circuit. The zone circuit is common to all the primary coils within the zone, but only one primary coil at a time can use the zone circuit. The local controller can use digital pinging or other current sensing techniques to determine whether a wireless power receiving device is located near the primary coil to which the local controller is currently connected. For example, when the local controller receives communication from the wireless power receiving device in response to a pinging operation, the local controller can determine that the wireless power receiving device is in proximity to the primary coil currently connected to the local controller. The local controller can cause the primary coil to supply wireless energy to the secondary coil of the wireless power receiving device. For example, the local controller operates a driver, and the connected primary coil can transmit wireless power. While the first primary coil of the zone is supplying power to the wireless power receiving device, the other primary coils remain disconnected based on the state of the relay.

[0041] In some implementations, the master controller can manage the states of the relays within a zone to effectively enable or disable different primary coils. Further, the wireless power transfer device may include a plurality of primary coil groups (zones) that can be connected or disconnected to respective zone circuits. The master controller manages the relays within the plurality of zones to prevent an adjacent primary coil from operating or transmitting a ping while the first primary coil is supplying power to the wireless power receiving device. For example, when a voltage is applied to an adjacent primary coil, the adjacent primary coil may generate unwanted EMI, which can interrupt the wireless power session of the first primary coil or affect the efficiency of the wireless power session. Thus, in some implementations, the master controller can disable or disconnect (also referred to as "mute") an adjacent primary coil to prevent the adjacent primary coil (near the first primary coil) from transmitting energy or transmitting a ping. Muting an adjacent primary coil can be accomplished either by preventing the adjacent primary coil from being connected to the local controller via a relay or by disabling the local controller within the adjacent zone.

[0042] In some implementations, the master controller can disable the zone circuit before changing the state of the zone relay. When current flows during relay switching due to the power connected via the relay, it may cause damage to the relay, a reduction in the relay's lifespan, or both. Therefore, in some implementations, the master controller can disable or stop the local controller within a zone before making changes to the relay connection within that zone. After a short period following the change in the relay state, the master controller can re-enable or operate the local controller again. This allows the relay to be completely changed in a zero-current environment, thus extending the relay's lifespan and improving the reliability of the local controller when detecting the wireless power receiving device.

[0043] In some implementations, the master controller may use a pattern when determining which primary coil of each zone to connect to each local controller. For example, when connecting the first primary coil to the first local controller and performing a digital ping or detection procedure, the master controller can prevent adjacent primary coils from being connected to their respective local controllers. Using this pattern, which primary coil sets ping can be switched alternately so that adjacent or nearby primary coils do not send pings simultaneously.

[0044] In some implementations, the primary coil is made of a material that improves the reliability and efficiency of the wireless power transmission device. For example, part or all of the primary coil may be made of a graphene material that has a higher conductivity and a smaller size than conventional materials (such as copper wire). The smaller the size, the thinner the layer of overlapping primary coils may be, and the more uniform the power transmission of primary coils in different layers may become.

[0045] Certain implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some implementations, the described techniques can be used to enable charging of one or more wireless power receiving devices in various positions and orientations. The efficiency of the wireless power transmitting device can be improved by selectively connecting separate primary coils to a local controller for each zone. Electronic devices within the wireless power transmitting device may use a modular design that uses common components for groups of primary coils that form different zones. By using fewer local controllers compared to a system that uses one local controller for each primary coil, the cost and complexity of the wireless power system can be reduced. Further, the ability to mute adjacent primary coils may improve the efficiency, speed, and reliability of powering a wireless power receiving device. For example, muting adjacent primary coils can prevent interference that would otherwise affect the charging time for charging a wireless power receiving device.

[0046] FIG. 1 shows an overview of components related to an exemplary wireless power system according to some implementations. The wireless power transmitter 110 can include a power source 180 configured to supply power to various zones within the wireless power transmitter 110. The power source 180 can convert alternating current (AC) to direct current (DC). The wireless power system 100 includes a wireless power transmitter 110 having a plurality of primary coils 120 (shown as primary coils 121, 122, 123, 124, 125, 126). Each of the primary coils 120 may be associated with a different zone circuit. For example, a first group of primary coils 121, 122, and 123 may be associated with a first zone 130. A second group of primary coils 123, 125, and 126 may be associated with a second zone 150. The first zone 130 may include a common zone circuit (including a first local controller 131). In the present disclosure, the terms zone circuit and local controller may be used interchangeably. However, it is understood that the zone circuit may include a local controller as well as other circuit components (including resistors, capacitors, drivers, etc.). Each primary coil may be a wire coil that transmits a wireless power signal (sometimes referred to as wireless energy). Each primary coil can transmit wireless energy using an inductive field or a magnetic resonance field (when connected to a local controller via a relay). The zone circuit may include components (not shown) for preparing the wireless power signal. For example, the zone circuit may include one or more switches, drivers, capacitors, or other components. An example of a zone circuit is included in FIG. 3. In some implementations, some or all of the zone circuit is embodied as an IC that implements the features of the present disclosure. Similar to the first zone 130, the second zone 150 may have a second local controller 132.

[0047] One or more relays 141 within the first zone 130 can control which of the primary coils 121, 122, and 123 are connected to the first local controller 131. Similarly, relay 142 can control which of the primary coils 124, 125, and 126 are connected to the second local controller 132. An example of relay 141 is included in FIG. 3. The master controller 170 can manage relays 141, 142 to control which primary coils of each zone 130, 150 are coupled to the local controller. For example, in FIG. 1, the master controller 170 configures relay 141 to connect the first primary coil 121 to the first local controller 131. While the first primary coil 121 is connected to the first local controller 131, the other primary coils 122 and 123 within the first zone 130 are disconnected. The master controller 170 has connected the second primary coil 125 to the second local controller 132, and the other primary coils 124 and 126 within the second zone 150 are disconnected.

[0048] There may be various ways to implement the master controller 170, including a microcontroller, a dedicated processor, an integrated circuit, an application-specific integrated circuit (ASIC), etc. In some implementations, the master controller may be collocated or integrated with one of the local controllers (such as the first local controller 131 or the second local controller 132). For example, an integrated circuit (IC) may implement the functions of both the master controller and one or more local controllers. Further, in some implementations, a local controller can perform some of the functions described as the master controller (in addition to the functions of the local controller), including polling of other local controllers, muting of adjacent primary coils, enabling / disabling of other local controllers, switching of connections between remote primary coils and another local controller, or any combination thereof.

[0049] When the first local controller 131 is connected to one of the primary coils 121, 122, 123 within the first zone, it may be configured to detect the presence or proximity of a wireless power receiving device. For example, the first local controller 131 may cause a detection signal to be periodically transmitted to the connected primary coil and measure a coil current or load change indicating that there is an object near the primary coil. In some implementations, the local controller may detect pinging, wireless communication, load modulation, etc. to determine that the wireless power receiving device is placed on the wireless power transmitting device. In some implementations, the transmission circuit may perform the detection irregularly or may operate independently to detect the wireless power receiving device. In some implementations, the transmission circuit may be configured to perform the detection stage in a pattern such that adjacent primary coils perform the detection stage at deterministic times to reduce interference from adjacent coils.

[0050] In the example of FIG. 1, the first wireless power receiving device 210 may be detected by the first primary coil 121. The first wireless power receiving device 210 has a secondary coil 220. The wireless power receiving device may be any type of device that can receive wireless power, including mobile phones, computers, laptops, peripheral devices, gadgets, robots, vehicles, and the like. When the wireless power receiving device (such as the first wireless power receiving device 210) is placed on the wireless power transmitting device 110 near the first primary coil 121 and the first local controller 131 is connected to the first primary coil 121 via the relay 141, the first local controller 131 can detect its presence. For example, during the detection stage, the first primary coil 121 may transmit a detection signal (sometimes called a ping). The coil current in the first primary coil 121 may be measured to determine whether a threshold indicating the presence of an object in the electromagnetic field of the first primary coil 121 has been exceeded. If an object is detected, the first local controller 131 may wait for a handshake signal (such as an identification signal, a setup signal, etc.) from the first wireless power receiving device 210 to determine whether the object is a wireless power receiving device or a foreign object. The first wireless power receiving device 210 may communicate the handshake signal using a series of load changes (such as load modulation). The load changes are detectable by a sensing circuit for the voltage or current of the coil and may be captured by the first primary controller 131. The first controller 131 may capture the load fluctuations and restore communication from the first wireless power receiving device 210. The communication may include information such as the charging level, the required voltage, the received power, the receiver power capability, and the support for wireless charging standards.

[0051] The first wireless power receiving device 210 may include a secondary coil 220, a rectifier 230, a receive (RX) controller 240, and an optional battery module 250. In some implementations, the battery module 250 can have an integrated charger (not shown). The secondary coil 220 can generate an induced voltage based on a wireless power signal received from the first primary coil 121. A capacitor (not shown) may be in series between the secondary coil 220 and the rectifier 230. The rectifier 230 can rectify the induced voltage and supply the rectified voltage to the battery module 250. The battery module 250 may be within the wireless power receiving device 210 or may be an external device coupled by an electrical interface. The battery module 250 may include a charging stage and protection circuits such as a temperature detection circuit, an overvoltage protection circuit, and an overcurrent protection circuit. Alternatively, the receive controller 240 may include a battery charging management module for collecting and processing information regarding the charge state of the battery module 250. In some implementations, the receive controller 240 may be configured to communicate with the first local controller 131 using load modulation via the secondary coil 220.

[0052] In the example of FIG. 1, since the first wireless power receiving device 210 is detected by the first primary coil 121, the master controller 170 can maintain a connection via the relay 141 between the first primary coil 121 and the first local controller 131. Accordingly, the other primary coils 122 and 123 within the first zone 130 remain disconnected and do not transmit pings or cause interference. However, the adjacent primary coil 126 may potentially interfere with the first primary coil 121. Accordingly, the master controller can prevent the relay 142 from connecting the primary coil 126 to the second local controller 132. In other words, the master controller may be configured to prevent adjacent primary coils from being connected to their respective local controllers even if the adjacent primary coils are part of another zone.

[0053] In the example of FIG. 1, the second wireless power receiving device 260 is near the second primary coil 125. As described above, the second local controller 132 can control the second primary coil 125 separately from other zones. Thus, the second local controller 132 may cause the second primary coil 125 to transmit wireless power to the second wireless power receiving device 260, and the first local controller 131 may cause the first primary coil 121 to transmit wireless power to the first wireless power receiving device 210. Further, the first local controller 131 and the second local controller 132 may individually manage parameters related to wireless charging at their respective primary coils. For example, for each of the first primary coil 121 and the second primary coil 125, the voltage level, resonance frequency, power level, or other parameters may be different based on the type of wireless power receiving device or the charging level of each battery.

[0054] In some implementations, the master controller 170 can adjust the operation of multiple local controllers. For example, the master controller 170 may manage the pattern of the detection stage for each zone based on the recognition of the adjacency of the primary coils.

[0055] The example of FIG. 1 shows only six primary coils 121, 122, 123, 124, 125, and 126 organized into two zones 130 and 150, but the number of primary coils and zones may be different. For example, the number of primary coils associated with each zone may be less than three or more than three. Further, the primary coils may be placed in an overlapping arrangement or a layered arrangement, with different zones defined between the arrangements. In some implementations, the zones may be based on which primary coils are close to each other, so that when zones share a common zone circuit, a relay for a certain zone effectively disables adjacent primary coils based on the zone relationship. Alternatively, a zone may include primary coils distributed throughout the wireless power transmission device.

[0056] FIG. 2A shows an exemplary wireless power transmission device having a plurality of layers of primary coils arranged in an overlapping pattern according to some implementations. The exemplary wireless power transmission device 200 includes 18 primary coils arranged in two overlapping layers. Again, the number and arrangement of the primary coils are shown as an example. Other numbers of primary coils, number of layers, or arrangements may be used. Further, the primary coils shown in FIG. 2 appear circular to help illustrate a partially overlapping pattern, but in other designs, non-circular primary coils may be used. For example, the primary coils may be squares (or rounded squares) similar to those shown in FIGS. 5-7. How a multi-layer system can provide a partially overlapping arrangement of the primary coils within a wireless power transmission device can be shown using the design of FIG. 2. In the present disclosure, a partially overlapping arrangement may include a design in which side portions overlap (or coincide).

[0057] As shown in FIG. 2A, the plurality of primary coils are distributed between a first layer 152 and a second layer 153. For example, the first primary coil 121 is shown on the first layer 152 along with some of the other primary coils. The second primary coil 125 is shown on the second layer 153 along with the other primary coils.

[0058] FIG. 2B shows the exemplary wireless power transmission device of FIG. 2A with a plurality of wireless power receiving devices being charged simultaneously according to some implementations. FIG. 2B includes the above-described layers 152, 153 as an assembled view 154 showing the coils in an overlapping state. In some implementations, the number of overlaps of the coils may be such that the plurality of primary coils cover substantially all of the charging surface 155.

[0059] In addition to the wireless power transmission device 200, FIG. 2B shows a first wireless power receiving device 210 and a second wireless power receiving device 260 placed on the charging surface 155. The first wireless power receiving device 210 can latch and receive wireless power from the first primary coil 121 based on its position on the transmission loop. Similarly, the second wireless power receiving device 260 can latch and receive wireless power from the second primary coil 125. Various optional features may be incorporated into the design of the wireless power transmission device. For example, in some implementations, a ferrite material may be used as part of the wireless power transmission device to maintain a consistent electromagnetic field. The ferrite material may be used to evenly distribute the electromagnetic field.

[0060] FIG. 3 shows an exemplary primary coil group that can be individually coupled to a local controller according to some implementations. The exemplary first zone 130 of FIG. 3 is one of a number of designs that can be used in the present disclosure. In the design of FIG. 3, the first zone 130 includes a first group of primary coils 121, 122, and 123, and a zone circuit 310. The zone circuit 310 includes a first local controller 131 that receives DC power using a DC input line 350 electrically coupled to a power source 180. The DC power may be a specific voltage (such as 5V or 12V). Alternatively, the local controller may include a power regulation stage to meet the voltage requirements of sub-modules within the local controller. The same DC voltage may be electrically coupled to some switches within the zone circuit 310, such as switch 330. The switch 330 may include a semiconductor switch such as a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). Alternatively, the switch 330 may include a mechanical switch. In the example of FIG. 3, each switch may be paired with a diode 320. Other components (such as drivers) are not shown in the figure but may be included in the path.

[0061] In addition, the first local controller 131 may switch the device so as to convert the power supply 180 from DC output to AC output across the center points of the two legs of the bridge. The coil voltage VAC is supplied to the local controller using the link 340. The switch can be used to control the voltage applied to the pair of the capacitor and the primary coil. For example, the first local controller 131 can change the duty ratio of each switch leg, the phase angle of the voltage applied between the switch legs, the frequency of the applied voltage, or a combination thereof. The first local controller 131, the switch, the driver, the diode, etc. may be regarded as the zone circuit 310. In some implementation forms, the driver may be incorporated into the first local controller 131. Further, the first local controller 131 may control the output of the zone circuit 310 using the control lines (marks 1, 2, 3, 4) to each switch. The first local controller 131 and the switch may be electrically coupled to the ground wire 360 to complete the circuit. The capacitor and the primary coil form a resonant circuit.

[0062] In some implementation forms, the zone circuit 310 may include a coil current sensing circuit (not shown). The zone circuit 310 may have a function of detecting a load change of the first primary coil 121. The coil current sensing circuit may be a current sensor connected in series with the first primary coil 121. The first local controller 131 may determine the presence or absence of an object based on the load change measured by the coil current sensing circuit. The local controller may use the sensed current, the sensed voltage VAC340, or a combination thereof to determine the load change. Also, a communication unit (not shown) may be present or may be incorporated into the first local controller 131. The communication unit can monitor the load change measured by the coil current sensing circuit and / or VAC340 and decode the load modulation data. The communication unit can receive the identification information (ID), the charge state information, the voltage control information, or other information reported by the wireless power receiving device.

[0063] Relay 141 is also shown in FIG. 3. Relay 141 includes a first relay 311 and a second relay 312. In the example of FIG. 3, two relays are used to switch the connection of the three primary coils 121, 122, 123 to the zone circuit 310. Relays 311, 312 may each have two states: normally open (NO) and normally closed (NC). The DC voltage 180 may be used to supply power to the coils (not shown) of relays 311 and 312 to switch the connection from NC to NO based on a control signal from a master controller (not shown). By changing the states of relays 311, 312, it is possible to connect the zone circuit 310 to a specific one of the primary coils. Table 1 shows the states of relays 311 and 312 in which different primary coils will be connected to the zone circuit 310. The example of Table 1 and FIG. 3 is provided for illustrative purposes only, and those skilled in the art can implement other combinations, relay circuits, or states.

Table 1

[0064] FIG. 4 shows an exemplary primary coil group according to some implementations and a local controller that can be managed by a master controller. Based on the description of FIG. 3, FIG. 4 shows how the master controller 170 can manage the operation of the first zone 130 including switches 311 and 312 and the first local controller 131. Other parts of the zone circuit are omitted from FIG. 4 for simplicity.

[0065] The master controller 170 may control a first control link 411 to the first relay 311 and a second control line 412 to the second relay 312. The first and second control lines may be on / off signals for switching the states of the relays 311, 312. However, as described above, if the states of the relays 311 and 312 are switched while current is flowing through one of the primary coils from the first local controller 131, it may cause a reduction in the lifespan of the relays. Therefore, in some implementations, the master controller 170 may have a control line 431 to the first local controller 131. The control line 431 may be used to enable or disable the first local controller 131. For example, the control line 431 may send a signal to the first local controller 131 to disable the electronic devices of the local controller (or any other zone circuit controlled by the local controller) so that no current flows through the relays 311 and 312. After disabling the first local controller 131, the master controller 170 may change the states of the relays 311 and 312. The master controller 170 may delay for a certain time period (e.g., 100 milliseconds) before sending an enable signal to the first local controller 131 via the control line 431.

[0066] In some implementations, the master controller 170 may also receive a status signal via a control line 441 from the first local controller 131 to the master controller 170. For example, the status signal may indicate to the wireless power receiving device whether the first local controller 131 is currently latched (powered on). In other examples, the status signal may indicate an operating state, a charging state, or other information available from the first local controller 131. In some implementations, the first local controller may determine the status signal based on a status such as communication from the first wireless power receiving device, a wireless power transmission state, generated electrical output to the first primary coil, a fault state related to charging of the first wireless power receiving device, or any combination thereof. In some implementations, the status signal may be an "on" signal or an "off" signal indicating whether the first local controller is successfully charging the wireless power receiving device. In some other implementations, the status signal may include a formatted message (e.g., tag - length - value (TLV), information element, or some other format for conveying additional status information). In yet other implementations, the status signal may be transmitted as a digital pulse signal via the control line 441. The master controller may be configured to capture the digital pulse signal and determine the status of the first local controller 131.

[0067] In some implementations, the status signal (or another interface between the first local controller and the master controller) may indicate a fault condition (such as due to overcurrent, foreign object detection, low quality factors, inconsistencies, etc.). In the case of a fault condition, the master controller may disable the first local controller 131 using the control line 431. For example, if the status signal indicates that the first local controller 131 has a poor connection to the wireless power receiving device or that a foreign object has been detected, the master controller 170 may disable the first local controller 131, change the states of the relays 311 and 312, and re-enable the first local controller 131 to check whether a better connection to the wireless power receiving device can be achieved with another primary coil.

[0068] FIG. 5 shows an exemplary arrangement using a plurality of primary coils according to several implementation forms. The charging surface of FIG. 5 shows the arrangement of 13 primary coils (numbered 1 to 13) grouped into 5 zones. The primary coils in each zone are shaded with a similar gray scale for easy reference. The first local controller 131 (associated with the first zone) can be coupled to any of the primary coils 1, 2, and 6 via a relay. The second local controller 132 (associated with the second zone) can be coupled to any of the primary coils 3, 4, and 8 via a relay. The third local controller 133 (associated with the third zone) can be coupled to any of the primary coils 5 and 10 via a relay. It should be noted that the first and second zones may have two relays (as described in FIG. 3), but since there are only two primary coils in the third zone, there may be only one relay in the third zone. The fourth local controller 134 (associated with the fourth zone) can be coupled to any of the primary coils 7, 11, and 12 via a relay. The fifth local controller 135 (associated with the fifth zone) can be coupled to any of the primary coils 9 and 13 via a relay. This arrangement is used to explain the exemplary scenarios of FIGS. 6 and 7. The figures of FIGS. 5 to 7 show the coils as non-overlapping, but in some implementation forms, the coils may partially overlap.

[0069] FIG. 5 shows that the master controller 170 can manage a plurality of zones. In particular, the master controller 170 may have control lines to each of the five zones in FIG. 5 (similar to the control lines 411, 412, 431, 441 described in FIG. 4). The master controller 170 can use the control lines to the relays in each zone to control which primary coils of the entire wireless power transmission device are connected to the respective local controllers 131, 132, 133, 134, and 135.

[0070] FIG. 6 shows an example of muting adjacent primary coils according to some implementation forms. In FIG. 6, the primary coil number 6 is charging a wireless power receiving device (not shown). Due to the zone and relay device configuration of the first zone, the other primary coils 1 and 2 in the first zone are not connected to the first local controller 131. To prevent interference with the primary coil 6, the master controller 170 may mute the other adjacent primary coils 5, 7, 10, and 11. For example, the master controller 170 may completely disable the third local controller 133, or may control the relay in the third zone so that the primary coils 5 and 10 are not connected to the third local controller 133. Similarly, the master controller 170 may control the relay in the fourth zone so that the primary coils 7 and 11 are not connected to the fourth local controller 134. Since the primary coil 12 in the fourth zone is not adjacent to the functioning primary coil 6, it can still be used. Therefore, the master controller 170 may control the relay in the fourth zone to connect the primary coil 12 to the fourth local controller 134. The fourth local controller 134 may use the primary coil 12 to periodically send a ping to determine whether a second wireless power receiving device may be placed in a part of the charging pad. Similarly, the other primary coils 3, 4, 8, 9, and 13 that are not adjacent to the primary coil 6 may be coupled to their respective local controllers so that they can send a ping to detect another wireless power receiving device that can be charged by the respective local controller.

[0071] FIG. 7 shows an exemplary pattern of digital pinging managed by a master controller according to some implementations. The master controller 170 can control the connections to each local controller of the primary coils to reduce or eliminate the number of adjacent primary coils that send pings simultaneously. In the example of FIG. 7, there may be four sets of coils that send pings at different times (distributed across the zone). The sets of coils are shown using different hatch marks for reference. Note that the exemplary pattern of FIG. 7 is for illustrative purposes only, and the actual pattern may vary depending on different implementations. Further, for simplicity, FIG. 7 is a diagram at a point in time where, currently, since the wireless power receiving device is not placed on the charging pad, all primary coils may be involved in the ping transmission pattern.

[0072] In the exemplary pattern shown in FIG. 7, in the first time period, primary coils 1, 3, 10, and 12 can send pings to detect the presence of the wireless power receiving device while the remaining primary coils are disconnected from their respective local controllers. After the first time period, the master controller 170 can 1) disable local controllers 131, 132, 133, 134, and 135, 2) disconnect primary coils 1, 3, 10, and 12, 3) connect local controllers 131, 132, 133, 134, and 135 to a different set of primary coils (primary coils 2, 4, 11, 13), and 4) re-enable local controllers 131, 132, 133, 134, and 135. Thus, in the first time period, primary coils 1, 3, 10, and 12 send pings, and in the second time period, primary coils 2, 4, 11, and 13 send pings. This pattern is such that in each time period, adjacent primary coils are not connected to the enabled local controllers. Continuing this pattern, in the third time period, primary coils 6 and 7 may be included. In the fourth time period, primary coils 5, 7, and 9 may be included.

[0073] FIG. 8 shows a flowchart illustrating an exemplary process for wireless power transfer according to some implementations. Flowchart 800 begins at block 810. At block 810, the wireless power transfer device can manage connections between a plurality of primary coils and respective local controllers via a plurality of relays. For example, the master controller can enable or disable a relay to change an electrical connection between a selected primary coil and a local controller in the same zone. At block 820, the wireless power transfer device can determine that a first primary coil among the plurality of primary coils is supplying wireless power to a first wireless power receiving device. For example, the wireless power transfer device can receive a status signal from a first local controller connected to the first primary coil. At block 830, the wireless power transfer device can operate the plurality of relays so that one or more adjacent primary coils near the first primary coil remain disconnected from their respective local controllers while the first primary coil is supplying wireless power to the first wireless power receiving device by the master controller. For example, after programmatically determining adjacent primary coils, the master controller can send a control signal to the relays in that zone to ensure that those adjacent primary coils are disconnected from the local controllers in the zone.

[0074] FIG. 9 shows a block diagram of an exemplary electronic device for use in a wireless power system according to some implementations. In some implementations, the electronic device 900 may be a wireless power transmitter (such as the wireless power transmitter 190). The electronic device 900 can include a processor 902 (which may include, in some cases, multiple processors, multiple cores, multiple nodes, or multithreading). The electronic device 900 can also include a memory 906. The memory 906 may be a system memory or any one or more of the realizable computer-readable media described herein. Also, the electronic device 900 can include a bus 990 (such as PCI, ISA, PCI-Express, HyperTransport (registered trademark), InfiniBand (registered trademark), NuBus (registered trademark), AHB, AXI, etc.).

[0075] The electronic device 900 may include a plurality of local controllers 962 configured to couple to a plurality of primary coils 966 via relays 964. A master controller 970 (similar to the master controller 170 described herein) may control the activation / deactivation of the local controllers 962 and also control the states of the relays 964. Further, the master controller 970 may receive status signals from the local controllers 962 regarding the current charging state or wireless power receiving device detection. In some implementations, the local controllers 962 may be distributed within the processor 902, the memory 906, and the bus 990. The local controllers 962 may perform some or all of the operations described herein, including the operations of the local controllers 131, 132, 133, 134, and 135. The memory 906 may include computer instructions executable by the processor 902 to implement the functions of the implementation forms described in FIGS. 1-7. Any one of these functions may be implemented partially (or wholly) in hardware or in the processor 902. For example, the function may be implemented in an application-specific integrated circuit, in the logic implemented in the processor 902, or in a coprocessor such as a peripheral device or a card. Further, components not shown in FIG. 9 may be reduced or added in the implementation. The processor 902, the memory 906, and the local controllers 962 may be coupled to the bus 990. Although shown as being coupled to the bus 990, the memory 906 may be coupled to the processor 902.

[0076] The operations described with reference to FIGS. 1-9 and herein are examples intended to assist in the understanding of exemplary implementations and should not be used to limit potential implementations or the scope of the claims. Some implementations may perform additional operations, fewer operations, operations in parallel or in a different order, and some different operations.

[0077] As used herein, the phrase "at least one of" or "one or more of" a list of items refers to any combination of those items, including a single member. For example, "at least one of a, b, or c" is intended to cover the possibilities of a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a, b, and c.

[0078] The various illustrative components, logics, logical blocks, modules, circuits, operations, and algorithmic processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or any combination of hardware, firmware, or software, including the structures disclosed herein and their structural equivalents. The interchangeability of hardware, firmware, and software has been generally described in terms of functionality and illustrated in the various illustrative components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends upon the particular application and design constraints imposed on the overall system.

[0079] The hardware and data processing apparatus used to implement the various exemplary components, logics, logic blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or carried out using a general-purpose single-chip or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gates or transistor logic, discrete hardware components, or any combination of these designed to perform the functions described herein. The general-purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration. In some implementations, certain processes, operations, and methods may be performed by circuits specialized for a given function.

[0080] As described above, in some aspects, implementations of the subject matter described in this specification can be implemented as software. For example, the various functions of the components disclosed in this specification, or the various blocks or steps of the methods, operations, processes, or algorithms disclosed in this specification, can be implemented as one or more modules of one or more computer programs. Such computer programs can include non-transitory processor or computer-executable instructions encoded on one or more tangible processors or computer-readable storage media for execution by, or to control the operation of, a data processing apparatus including the components of the devices described in this specification. By way of example and not limitation, such storage media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store program code in the form of instructions or data structures. Combinations of the above should also be included within the scope of storage media.

[0081] Various changes to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the scope of the disclosure. Accordingly, the claims are not intended to be limited to the implementations shown herein, but rather should be accorded the widest scope consistent with the disclosure, principles, and novel features disclosed herein.

[0082] Furthermore, the various features described herein in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, the various features described in the context of a single implementation can also be implemented separately in multiple implementations or in any suitable partial combination. Thus, features may be described as functioning in a particular combination and may initially be claimed as such, but one or more features from the claimed combination may, in some cases, be deleted from that combination, and the claimed combination may be directed to a partial combination or a variation of a partial combination.

[0083] Similarly, while operations are shown in the drawings in a particular order, this should not be understood as requiring that the operations be performed in the particular order shown or in a sequential order in order to obtain a desirable result, or that all of the operations shown be performed. Further, the drawings can schematically depict one or more exemplary processes in the form of a flowchart or a flow diagram. However, other operations not shown can be incorporated into the exemplary processes schematically shown. For example, one or more additional operations can be performed before, after, concurrently with, or between any of the illustrated operations. In some situations, multitasking and parallel processing may be advantageous. It should be understood that the separation of the various system components in the above-described implementations is not necessarily required in all implementations, and that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Claims

1. A wireless power transmitting device, a plurality of primary coils organized into at least a first primary coil group and a second primary coil group; at least a first local controller associated with the first primary coil group and a second local controller associated with the second primary coil group; a plurality of switches each capable of individually coupling the first local controller to one of the primary coils in the first primary coil group and the second local controller to one of the primary coils in the second primary coil group; a master controller configured to operate the plurality of switches to control which primary coils of the first primary coil group are coupled to the first local controller and which primary coils of the second primary coil group are coupled to the second local controller; and A wireless power transmission device comprising:

2. The master controller: determining that a first primary coil of the plurality of primary coils is supplying wireless power to a first wireless power receiving device; 2. The wireless power transmitting device of claim 1, further configured to operate the multiple switches such that one or more adjacent primary coils in a vicinity of the first primary coil remain decoupled from their respective local controllers while the first primary coil is supplying the wireless power to the first wireless power receiving device.

3. The master controller: disabling the first local controller prior to changing a state of a plurality of switches to control which primary coils of the first primary coil group are coupled to the first local controller, and disabling the first local controller prevents current from flowing from the first local controller through the plurality of switches while the states of the plurality of switches are being changed; 2. The wireless power transmitting device of claim 1, further configured to enable the first local controller after changing states of the plurality of switches to control which primary coils of the first primary coil group are coupled to the first local controller.

4. The plurality of switches include a first set of switches configured to individually couple the first local controller to one primary coil of the first group of primary coils; a second set of switches configured to individually couple the second local controller to one primary coil of the second group of primary coils; The wireless power transmitting device according to claim 1 .

5. The system further includes a plurality of local controllers including at least the first local controller and the second local controller, wherein at least the first local controller: a communication unit capable of receiving communication from the first wireless power receiving device via the first primary coil when the first wireless power receiving device is in proximity to the first primary coil and the first local controller is connected to the first primary coil; a control unit configured to manage an operation of a driver in response to receiving the communication from the first wireless power receiving device; Including, 2. The wireless power transmitter of claim 1, wherein the driver is configured to generate an electrical output to the first primary coil when the first primary coil is coupled to the first local controller via the plurality of switches.

6. The first local controller determining a status signal to send to the master controller, the status signal based at least in part on the communication from the first wireless powered device, a wireless power transfer status, the electrical output generated at the first primary coil, a fault condition associated with charging the first wireless powered device, or any combination thereof; The wireless power transmitting device according to claim 5 , configured to transmit the status signal to the master controller.

7. The master controller: determining, based at least in part on the status signal, that the first primary coil is not providing wireless power to the first wireless power receiver; 7. The wireless power transmitting apparatus of claim 6, further configured to operate the plurality of switches to couple the first local controller to one or more other primary coils of the first primary coil group.

8. The master controller: determining, based at least in part on the status signal, that the first primary coil is providing wireless power to the first wireless power receiver; 7. The wireless power transmitting device of claim 6, further configured to prevent the plurality of switches from decoupling the first local controller from the first primary coil while the status signal indicates that the first primary coil is supplying wireless power to the first wireless power receiving device.

9. The master controller:

9. The wireless power transmitting device of claim 8, further configured to prevent the multiple switches from coupling one or more adjacent primary coils in a vicinity of the first primary coil to a respective local controller while the status signal indicates that the first primary coil is supplying the wireless power to the first wireless power receiving device.

10. The master controller: causing the plurality of switches to sequentially couple primary coils of the first primary coil group to the first local controller; 2. The wireless power transmitting device of claim 1, further configured to receive, for each primary coil in the first primary coil group, a status signal from the first local controller indicating whether the first local controller has detected a first wireless power receiving device at the coupled primary coil.

11. The master controller:

2. The wireless power transmitting device of claim 1, further configured to cause the plurality of switches to simultaneously couple a first primary coil of the first primary coil group to the first local controller and a second primary coil of the second primary coil group to the second local controller, wherein the first primary coil and the second primary coil are not adjacent to each other.

12. The master controller:

13. The wireless power transmitting apparatus of claim 1, further configured to operate the plurality of switches such that each of the plurality of primary coils is coupled to a respective local controller according to a pattern that prevents adjacent primary coils from being simultaneously coupled.

13. 2. The wireless power transmitting device of claim 1, wherein each primary coil group includes at least two primary coils that can be selectively coupled to a local controller, and each primary coil group is coupled to the local controller for that group via at least one switch.

14. The wireless power transmitting apparatus of claim 13 , wherein the first primary coil group includes three primary coils selectively coupleable to the first local controller via two relays.

15. 13. The wireless power transmitting device of claim 1, further comprising a charging pad on which the plurality of wireless power receiving devices can be placed, the plurality of primary coils being arranged in an overlapping pattern distributed across multiple layers of the charging pad.

16. The wireless power transmitter of claim 15 , wherein at least a subset of the plurality of primary coils is constructed from graphene.

17. when a first wireless power receiving device is in proximity to the first primary coil and the first local controller is coupled to the first primary coil, the first local controller is configured to, in response to communication from the first wireless power receiving device via the first primary coil, cause at least a first primary coil of the first primary coil group to transmit wireless power to the first wireless power receiving device; 2. The wireless power transmitting device of claim 1, wherein when a second wireless power receiving device is in proximity to the second primary coil and the second local controller is coupled to the second primary coil, the second local controller is configured to cause at least a second primary coil of the second primary coil group to transmit wireless power to the second wireless power receiving device in response to communication from the second wireless power receiving device via the second primary coil.

18. 17. The wireless power transmitting device of claim 16, wherein the first primary coil and the second primary coil are not adjacent to each other, and the first primary coil and the second primary coil are configured to simultaneously transmit wireless power to the first wireless power receiving device and the second wireless power receiving device, respectively.

19. The wireless power transmitting device of claim 1 , wherein the plurality of switches comprises relays that are remotely controlled switches managed by the master controller.

20. 1. A method for wireless power transmission by a wireless power transmission device, comprising: managing connections between the plurality of primary coils and respective local controllers via a plurality of switches; determining that a first primary coil of the plurality of primary coils is supplying wireless power to a first wireless power receiving device; operating, by a master controller, states of the plurality of switches such that one or more adjacent primary coils in a vicinity of the first primary coil remain decoupled from their respective local controllers while the first primary coil is supplying the wireless power to the first wireless power receiving device; A method comprising:

21. 21. The method of claim 20, wherein the plurality of primary coils are organized into at least a first primary coil group that can be individually coupled to a first local controller via a first subset of the plurality of switches, and a second primary coil group that can be individually coupled to a second local controller via a second subset of the plurality of switches.

22. disabling the first local controller prior to changing a state of a plurality of switches to control which primary coils of the first primary coil group are coupled to the first local controller, where disabling the first local controller prevents current from flowing from the first local controller through the plurality of switches while the states of the plurality of switches are being changed; after changing the states of the plurality of switches, enabling the first local controller to control which primary coils of the first primary coil group are coupled to the first local controller; 22. The method of claim 21 further comprising:

23. receiving, by the first local controller, a communication from the first wireless power receiving device via the first primary coil when the first wireless power receiving device is in proximity to the first primary coil and the first local controller is coupled to the first primary coil; determining, by the first local controller, a status signal to send to the master controller, the status signal based at least in part on the communication from the first wireless power receiver, a wireless power transfer status, the electrical output generated at the first primary coil, a fault condition associated with charging the first wireless power receiver, or any combination thereof; transmitting the status signal from the first local controller to the master controller; 22. The method of claim 21 further comprising:

24. determining, based at least in part on the status signal, that the first primary coil is not providing wireless power to the first wireless power receiver; operating the plurality of switches to couple the first local controller to one or more other primary coils of the first primary coil group; 24. The method of claim 23, further comprising:

25. determining, by the master controller, that the first primary coil is providing wireless power to the first wireless power receiver based at least in part on the status signal; preventing, by the master controller, the plurality of switches from decoupling the first local controller from the first primary coil while the status signal indicates that the first primary coil is providing wireless power to the first wireless power receiving device; 24. The method of claim 23, further comprising:

26. 26. The method of claim 25, further comprising: preventing the multiple switches from coupling one or more adjacent primary coils in a vicinity of the first primary coil to a respective local controller while the status signal indicates that the first primary coil is supplying the wireless power to the first wireless powered device.

27. causing the plurality of switches to sequentially couple primary coils of a first primary coil group to a first local controller; receiving, for each primary coil in the first primary coil group, a status signal from the first local controller indicating whether the first local controller has detected the first wireless power receiving device at the associated primary coil; 21. The method of claim 20, further comprising:

28. 21. The method of claim 20, further comprising: causing the plurality of switches to simultaneously couple the first primary coil of a first primary coil group to a first local controller and the second primary coil of a second primary coil group to a second local controller, wherein the first primary coil and the second primary coil are not adjacent to one another.

29. 21. The method of claim 20, further comprising operating the plurality of switches such that each of the plurality of primary coils is coupled to a respective local controller according to a pattern that prevents adjacent primary coils from being simultaneously coupled.

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