Wireless chargers and charging methods for electronic devices

Abstract

A method is disclosed for charging an electronic device via a wireless charger having a set of transmitting coils and multiple magnetic field sensors. The method may include measuring a magnetic field in a predetermined charging area to detect changes in the magnetic field, and selecting a subset of transmitter coils associated with one of the magnetic field sensors. The method may further include energizing each transmitter coil in the subset of transmitter coils to transmit a predetermined maximum output power, selecting one transmitter coil from the subset of transmitter coils, determining a first output power of the selected transmitter coil, and energizing the selected transmitter coil to transmit the first output power.

Description

Technical Field

[0001] This disclosure relates to a wireless charger and a charging method for an electronic device. Background Technology

[0002] Wireless chargers have been developed that allow battery-powered electronic devices, such as mobile phones, the latest headphones, wearable health monitors, and smartwatches, to charge without a physical charging connection. Typically, a wireless charger uses a charging coil or "transmitting" coil placed beneath the charging surface to generate a magnetic field, inducing a current in the corresponding receiving coil of the electronic device to generate electrical energy. This induced current is then used to charge the battery of the electronic device.

[0003] Typical wireless chargers draw power from an external power source, such as alternating current (AC), to energize a transmitting coil and generate a magnetic field. Therefore, such wireless charging devices require a physical connection to an external power source, which limits their usability and portability.

[0004] Furthermore, typical wireless chargers usually require the electronic device to be placed in a specific position on a relatively small charging surface with a specific orientation, ensuring proper alignment between the receiving coil in the electronic device and the corresponding transmitting coil in the wireless charger. This alignment enables electromagnetic coupling to allow the device to draw power from the transmitting coil in the wireless charging system. If the receiving and transmitting coils are not aligned, the electronic device may not be able to draw sufficient power from the transmitting coil, potentially reducing power transfer efficiency.

[0005] To allow electronic devices to be placed freely on the charging surface of a wireless charger, some wireless chargers have been developed that include multiple transmitting coils beneath the charging surface, ensuring sufficient coupling between at least one transmitting coil and the receiving coil of the electronic device. However, if the receiving coil and its corresponding transmitting coil are misaligned, efficient power transfer may still be impossible. Furthermore, in such a setup, all transmitting coils are typically energized simultaneously, which can lead to excessive heat generation, and interference due to overlapping magnetic fields from each transmitting coil can cause intermittent charging. Moreover, regardless of the battery level of the electronic device at any given time, each transmitting coil generally transmits power at a single output power. This also results in inefficient power transfer between the wireless charger and the electronic device. Summary of the Invention

[0006] The purpose of this disclosure is to substantially overcome or improve one or more of the above-mentioned disadvantages, or at least to provide an effective alternative.

[0007] One aspect of this disclosure provides a method for charging an electronic device having a receiving coil via a wireless charger having a set of transmitting coils and a plurality of magnetic field sensors, each magnetic field sensor being associated with a subset of the transmitting coils, the method comprising:

[0008] The magnetic field sensor is used to measure the magnetic field of a predetermined charging area;

[0009] A change in magnetic field was detected based on the measurement results of one of the magnetic field sensors, indicating that the electronic device is in the charging area;

[0010] Select a subset of transmitting coils associated with one of the magnetic field sensors;

[0011] Each transmitting coil in the subset of transmitting coils is energized to transmit a predetermined maximum output power to the receiving coil;

[0012] Based on the measurement results of one of the magnetic field sensors, a transmitting coil is selected from the subset of transmitting coils;

[0013] Based on the measurement results of one of the magnetic field sensors, the first output power of the transmitting coil is determined; and

[0014] The transmitting coil is energized to transmit a first output power to the receiving coil.

[0015] Selecting a transmitting coil from the subset of transmitting coils may include:

[0016] The mutual inductance coefficient between each transmitting coil and the receiving coil in the subset of transmitting coils is calculated based on the measurement results of one of the magnetic field sensors; and

[0017] The mutual inductance coefficient is compared with a predetermined inductance range to select one of the transmitting coils from the subset of transmitting coils.

[0018] The predetermined inductance range is between 125 and 860 microhenries.

[0019] Determining the first output power of the transmitting coil may include:

[0020] The first output power is selected from a first set of predetermined output powers associated with the mutual inductance coefficient between the transmitting coil and the receiving coil.

[0021] Selecting a transmitting coil from the subset of transmitting coils may include:

[0022] Based on the measurement results of one of the magnetic field sensors, a misalignment correction value between each transmitting coil and the receiving coil in the subset of transmitting coils is calculated;

[0023] Based on their respective misalignment correction values ​​and the measurement results of one of the magnetic field sensors, the mutual inductance coefficient between each transmitting coil and the receiving coil in the subset of transmitting coils is calculated; and

[0024] The mutual inductance coefficient is compared with a predetermined inductance range to select one of the transmitting coils from the subset of transmitting coils.

[0025] The predetermined inductance range is between 125 and 860 microhenries.

[0026] Determining the first output power of the transmitting coil may include:

[0027] The first output power is selected from a first set of predetermined output powers associated with the mutual inductance coefficient between the transmitting coil and the receiving coil.

[0028] After energizing the transmitting coil to transmit the first output power, the method may further include:

[0029] Receive power data from the electronic device;

[0030] The second output power is calculated based on the power data, the first output power, and the misalignment correction value between the transmitting coil and the receiving coil; and

[0031] The transmitting coil is energized to transmit the second output power to the receiving coil.

[0032] The power data may include the voltage of the electronic device's battery.

[0033] In some embodiments, the predetermined maximum output power can be between 20 and 100 watts. In one embodiment, the predetermined maximum output power is approximately 25 watts.

[0034] Another aspect of this disclosure provides a wireless charger for charging an electronic device having a receiving coil, the wireless charger comprising:

[0035] A housing having a charging surface, and defining a predetermined charging area above the charging surface;

[0036] A set of transmitting coils;

[0037] Multiple magnetic field sensors associated with a subset of the transmitting coil;

[0038] A memory or storage device for storing processor-executable instructions; and

[0039] A processor, connected to the memory or storage device, the transmitting coil, and the magnetic field sensor, the processor being configured to execute stored processor-executable instructions, wherein executing the stored processor-executable instructions causes the processor to:

[0040] The magnetic field sensor is used to measure the magnetic field of a predetermined charging area;

[0041] A change in magnetic field was detected based on the measurement results of one of the magnetic field sensors, indicating that the electronic device is in the charging area;

[0042] Select a subset of transmitting coils associated with one of the magnetic field sensors;

[0043] Each transmitting coil in the subset of transmitting coils is energized to transmit a predetermined maximum output power to the receiving coil;

[0044] Based on the measurement results of one of the magnetic field sensors, a transmitting coil is selected from the subset of transmitting coils;

[0045] Based on the measurement results of one of the magnetic field sensors, the first output power of the transmitting coil is determined; and

[0046] The transmitting coil is energized to transmit the first output power to the receiving coil.

[0047] Executing the stored processor-executable instructions enables the processor to select a transmitter coil from the subset of transmitter coils in the following manner:

[0048] Based on the measurement results of one of the magnetic field sensors, the mutual inductance coefficient between each transmitting coil and the receiving coil in the subset of transmitting coils is calculated; and

[0049] The mutual inductance coefficient is compared with a predetermined inductance range to select one of the transmitting coils from the subset of transmitting coils.

[0050] The predetermined inductance range is between 125 and 860 microhenries.

[0051] Executing the stored processor-executable instructions enables the processor to determine the first output power of the transmitting coil in the following manner:

[0052] The first output power is selected from a first set of predetermined output powers associated with the mutual inductance coefficient between the transmitting coil and the receiving coil.

[0053] Executing the stored processor-executable instructions enables the processor to select a transmitter coil from the subset of transmitter coils in the following manner:

[0054] Based on the measurement results of one of the magnetic field sensors, a misalignment correction value between each transmitting coil and the receiving coil in the subset of transmitting coils is calculated;

[0055] Based on their respective misalignment correction values ​​and the measurement results of one of the magnetic field sensors, the mutual inductance coefficient between each transmitting coil and the receiving coil in the subset of transmitting coils is calculated; and

[0056] The mutual inductance coefficient is compared with a predetermined inductance range to select one of the transmitting coils from the subset of transmitting coils.

[0057] The predetermined inductance range is between 125 and 860 microhenries.

[0058] Executing the stored processor-executable instructions enables the processor to determine the first output power of the transmitting coil in the following manner:

[0059] The first output power is selected from a first set of predetermined output powers associated with the mutual inductance coefficient between the transmitting coil and the receiving coil.

[0060] The wireless charger may further include a wireless communication module connected to the processor. After executing the stored processor-executable instructions to energize one of the transmitting coils to transmit a first output power, the execution of the stored processor-executable instructions further causes the processor to:

[0061] The power data received from the electronic device is received through the wireless communication module;

[0062] The second output power is calculated based on the power data, the first output power, and the misalignment correction value between the transmitting coil and the receiving coil; and

[0063] The transmitting coil is energized to transmit the second output power to the receiving coil.

[0064] The power data includes the voltage of the electronic device's battery.

[0065] In some embodiments, the predetermined maximum output power can be between 20 and 100 watts. In one embodiment, the predetermined maximum output power can be approximately 25 watts.

[0066] Each magnetic field sensor can be a triaxial magnetometer.

[0067] In some embodiments, the wireless charger further includes a power source. In one embodiment, the power source may be a battery.

[0068] Another aspect of this disclosure provides a method for charging an electronic device having a receiving coil via a wireless charger having multiple transmitting coils and a magnetic field sensor, the method comprising:

[0069] The magnetic field sensor is used to measure the magnetic field within the predetermined charging area;

[0070] Based on the measurement results of the magnetic field sensor, one transmitting coil is selected from the plurality of transmitting coils;

[0071] The first output power of the transmitting coil is determined based on the measurement results of the magnetic field sensor; and

[0072] The transmitting coil is energized to transmit the first output power to the receiving coil.

[0073] The method may further include:

[0074] Before selecting one of the transmitting coils, each of the plurality of transmitting coils is energized in order to transmit a predetermined maximum output power to the receiving coil in the predetermined charging region.

[0075] Selecting a transmitting coil may include:

[0076] Based on the measurement results of the magnetic field sensor, the mutual inductance coefficient between each of the plurality of transmitting coils and the receiving coil is calculated; and

[0077] The mutual inductance coefficient is compared with a predetermined inductance range to select one of the plurality of transmitting coils.

[0078] The predetermined inductance range is between 125 and 860 microhenries.

[0079] Determining the first output power of the transmitting coil may include:

[0080] The first output power is selected from a first set of predetermined output powers associated with the mutual inductance coefficient between the transmitting coil and the receiving coil.

[0081] Selecting a transmitting coil may include:

[0082] Based on the measurement results of the magnetic field sensor, the misalignment correction value between each of the plurality of transmitting coils and the receiving coil is calculated;

[0083] Based on their respective misalignment correction values ​​and the measurement results of the magnetic field sensor, the mutual inductance coefficient between each of the plurality of transmitting coils and the receiving coil is calculated; and

[0084] The mutual inductance coefficient is compared with a predetermined inductance range to select one of the plurality of transmitting coils.

[0085] The predetermined inductance range is between 125 and 860 microhenries.

[0086] Determining the first output power of the transmitting coil may include:

[0087] A first output power is selected from a first set of predetermined output powers associated with the mutual inductance coefficient between the transmitting coil and the receiving coil.

[0088] After the transmitting coil is energized to transmit the first output power, the method may further include:

[0089] Receive power data from the electronic device;

[0090] The second output power is determined based on the power data, the first output power, and the misalignment correction value between the transmitting coil and the receiving coil; and

[0091] The transmitting coil is energized to transmit the second output power to the receiving coil.

[0092] The power data includes the voltage of the electronic device's battery.

[0093] Another aspect of this disclosure provides a wireless charger for charging an electronic device having a receiving coil, the wireless charger comprising:

[0094] A housing having a charging surface, and defining a predetermined charging area above the charging surface;

[0095] Multiple transmitting coils;

[0096] A magnetic field sensor;

[0097] A memory or storage device for storing processor-executable instructions; and

[0098] A processor, connected to the memory or storage device, the transmitting coil, and the magnetic field sensor, is configured to execute stored processor-executable instructions, wherein executing the stored processor-executable instructions causes the processor to:

[0099] The magnetic field of the predetermined charging area is measured using the magnetic field sensor.

[0100] Based on the measurement results of the magnetic field sensor, one transmitting coil is selected from the plurality of transmitting coils;

[0101] Based on the measurement results of the magnetic field sensor, the first output power of the transmitting coil is determined; and

[0102] The transmitting coil is energized to transmit the first output power to the receiving coil.

[0103] Executing the stored processor-executable instructions further enables the processor to:

[0104] Before selecting one of the transmitting coils, each of the plurality of transmitting coils is energized in order to transmit a predetermined maximum output power to the receiving coil in the predetermined charging region.

[0105] Executing the stored processor-executable instructions enables the processor to select a transmitter coil in the following manner:

[0106] Based on the measurement results of the magnetic field sensor, the mutual inductance coefficient between each of the plurality of transmitting coils and the receiving coil is calculated; and

[0107] The mutual inductance coefficient is compared with a predetermined inductance range to select one of the plurality of transmitting coils.

[0108] The predetermined inductance range is between 125 and 860 microhenries.

[0109] Executing the stored processor-executable instructions enables the processor to determine the first output power of the transmitting coil in the following manner:

[0110] The first output power is selected from a first set of predetermined output powers associated with the mutual inductance coefficient between the transmitting coil and the receiving coil.

[0111] Executing the stored processor-executable instructions enables the processor to select a transmitter coil from the subset of transmitter coils in the following manner:

[0112] Based on the measurement results of the magnetic field sensor, the misalignment correction value between each of the plurality of transmitting coils and the receiving coil is calculated;

[0113] Based on their respective misalignment correction values ​​and the measurement results of the magnetic field sensor, the mutual inductance coefficient between each of the plurality of transmitting coils and the receiving coil is calculated; and

[0114] The mutual inductance coefficient is compared with a predetermined inductance range to select one of the plurality of transmitting coils.

[0115] The predetermined inductance range is between 125 and 860 microhenries.

[0116] Executing the stored processor-executable instructions enables the processor to determine the first output power of the transmitting coil in the following manner:

[0117] The first output power is selected from a first set of predetermined output powers associated with the mutual inductance coefficient between the transmitting coil and the receiving coil.

[0118] The wireless charger may further include a wireless communication module connected to the processor. After executing the stored processor-executable instructions to energize the one transmitting coil to transmit the first output power, the execution of the stored processor-executable instructions further causes the processor to:

[0119] The power data of the electronic device is received through the wireless communication module;

[0120] The second output power is calculated based on the power data, the first output power, and the misalignment correction value between the transmitting coil and the receiving coil; and

[0121] The transmitting coil is energized to transmit the second output power to the receiving coil.

[0122] The power data includes the voltage of the electronic device's battery.

[0123] Each magnetic field sensor can be a triaxial magnetometer.

[0124] In some embodiments, the wireless charger may further include a power source. In one embodiment, the power source may be a battery. Attached Figure Description

[0125] Embodiments of this disclosure will now be described below by way of example with reference to the accompanying drawings, in which:

[0126] Figure 1 This is a top view of one embodiment of a wireless charger;

[0127] Figure 2 yes Figure 1 A perspective view of a wireless charger;

[0128] Figure 3 yes Figure 1 Front view of a wireless charger;

[0129] Figure 4 yes Figure 1 A schematic diagram of a wireless charger, which includes electronic devices and an external power source;

[0130] Figure 5 This is a top view of a coil array in one embodiment;

[0131] Figure 6 yes Figure 1 The top view of the wireless charger shown illustrates... Figure 5 coil arrays and multiplexers;

[0132] Figure 7 This is a schematic diagram of a 16:1 multiplexer tree in one embodiment;

[0133] Figure 8 This is a top view of a coil array according to another embodiment;

[0134] Figure 9 This is a top view of a coil array according to another embodiment;

[0135] Figure 10 yes Figure 9 A cross-sectional view of the coil array along line AA;

[0136] Figure 11 In one embodiment, through Figure 1 A flowchart illustrating a method for a wireless charger to charge electronic devices;

[0137] Figure 12 yes Figure 1 A top view of a wireless charger, with an electronic device placed on it;

[0138] Figure 13 yes Figure 1 A top-down view of a wireless charger, on which two electronic devices are placed; and

[0139] Figure 14 This is a top view of a coil array according to another embodiment. Detailed Implementation

[0140] Figures 1 to 4 An embodiment of a wireless charger 10 for charging an electronic device 20 is shown. In this embodiment, the electronic device 20 has a single receiving coil 22; however, it should be understood that in other embodiments, the electronic device 20 may include multiple receiving coils 22. The electronic device 20 may include a mobile phone, headphones or earphones, a wireless earbud or earphone housing, a wearable health monitoring device, a smartwatch, a tablet, a laptop, or any other device of the wireless charging type.

[0141] In this embodiment, the wireless charger 10 is designed to charge the electronic device 20 according to the Qi standard. However, it is understood that the wireless charger 10 may also be designed to charge the electronic device 20 according to other wireless charging protocols.

[0142] refer to Figure 1The wireless charger 10 has a housing 100 that houses the electronic components of the wireless charger 10. The housing 100 includes a flat, upward-facing charging surface 102 on which one or more electronic devices 20 can be placed. The charging surface 102 defines a boundary having a length L1 along the x-axis and a length L2 along the y-axis. Figure 2 As shown, the wireless charger 10 also defines a predetermined charging area 104 above the charging surface 102.

[0143] Now please see Figure 4 The electronic components of the wireless charger 10 include a power source 106 for a direct current (DC) rechargeable battery, for providing electrical energy to the components of the wireless charger 10.

[0144] The electronic components of the wireless charger 10 also include a computing unit 108. The computing unit 108 is a microcontroller 108, which includes a processor 110 and a memory 112. The memory 112 is used to store information and / or instructions for controlling the processor 110, and may be, for example, read-only memory (ROM), random access memory (RAM), or both. The processor 110 is used to execute instructions, such as those stored in the memory 112. In this embodiment, the microcontroller 108 is a Cortex-A34 microcontroller.

[0145] In other embodiments, the microcontroller 108 may have a storage device, such as a hard disk drive (HDD).

[0146] The electronic components of the wireless charger 10 also include a transmitting circuit 114 having a set of transmitting coils 116 disposed below the charging surface 102. Each transmitting coil 116 is configured to wirelessly transmit electrical energy to a receiving coil 22 of the electronic device 20. Specifically, each transmitting coil 116 generates an induced magnetic field along the Z-axis that is substantially orthogonal to the charging surface 102. The induced magnetic fields of each adjacent transmitting coil 116 overlap. In this embodiment, as... Figure 5 As shown, a set of transmitting coils 116 has 16 circular transmitting coils 116, each coil 116 is equidistant along the plane and arranged in a 4x4 coil array 118. The transmitting coils 116 can be fabricated on a substrate, such as a printed circuit board (PCB).

[0147] The transmitter circuit 114 also includes multiplexers 120 that connect each transmitting coil 116 in the coil array 118 to the processor 110 and the power supply 106. Under the control of the processor 110, the multiplexers 120 are used to output the required power from the power supply 106 to one or more transmitting coils 116 at any given time. In this embodiment, as... Figure 7 As shown, the multiplexer 120 communicates with a set of four 4:1 primary multiplexers MUX(β) and a set of secondary multiplexers MUX(α), thus forming a 16:1 multiplexer tree. Each set of 4:1 primary multiplexers MUX(β) is connected to a corresponding subset consisting of four transmit coils 116 to define four quadrants Q1, Q2, Q3, and Q4 in the coil array 118. For illustration, these quadrants are... Figure 5 The dotted lines in the diagram define the quadrant. This means that transmitting coils T1, T2, T3, and T4 define quadrant Q1; transmitting coils T5, T6, T7, and T8 define quadrant Q2; transmitting coils T9, T10, T11, and T12 define quadrant Q3; and transmitting coils T13, T14, T15, and T16 define quadrant Q4.

[0148] although Figure 5 The illustrated embodiment includes 16 transmitting coils 116 of the same shape and size, but any suitable design can be used for the transmitting coils 116. Furthermore, each transmitting coil 116 can be made of any suitable shape, size, and material. Additionally, the coil array 118 can include any suitable number of transmitting coils 116, and the transmitting coils 116 can be arranged in any suitable manner. For example, as... Figures 8 to 10 As shown, the transmitting coils 116 can be arranged in a three-dimensional coil array of various shapes, wherein each transmitting coil 116 partially overlaps with its adjacent transmitting coil 116. Additionally, the transmitter circuit 114 can also include any suitable number of multiplexers 120, arranged in a manner corresponding to the number of transmitting coils 116 in the wireless charger 10.

[0149] In some embodiments, the wireless charger 10 may further include a shielding sleeve (not shown) made of ferrite or other materials, disposed between the coil array 118 and the computing unit 108. As those skilled in the art will know, the shielding sleeve protects the computing unit 108 from the magnetic field emitted by the coil array 118 and helps to increase the magnetic field density above the coil array 118.

[0150] The electronic components of the wireless charger 10 also include a plurality of magnetic field sensors 122 disposed below the coil array 118. Each magnetic field sensor 122 is a triaxial magnetometer 122, such as a Honeywell HMR2300 magnetometer, and is connected to the processor 110. Each magnetometer 122 is spaced apart from each other along a plane and located at a predetermined position on the charging surface 102. In this embodiment, as... Figure 6 As shown, the wireless charger includes four magnetometers 122, each located near the transmitting coil 116 in a respective quadrant for association with it. This means that magnetometer M1 is associated with transmitting coils T1, T2, T3, and T4; magnetometer M2 is associated with transmitting coils T5, T6, T7, and T8; magnetometer M3 is associated with transmitting coils T9, T10, T11, and T12; and magnetometer M4 is associated with transmitting coils T13, T14, T15, and T16. Each magnetometer 122 measures the strength and direction of the magnetic field emitted from the associated transmitting coil 116 in its vicinity.

[0151] In addition, the electronic components of the wireless charger 10 also include a wireless communication module 124, which is a wireless transceiver 124 connected to the processor 110 for data transmission therebetween. The wireless communication module 124 can communicate with the rechargeable electronic device 20 via any wireless technology, such as Bluetooth, Near Field Communication (NFC), or Radio Frequency Identification (RFID). The wireless communication module 124 is configured to route transmitted and received data signals input to and output from the wireless charger 10. For example, input data signals from the electronic device 20, such as power data, are routed through the wireless communication module 124 before being input to the processor 110, while output data signals from the processor 110 are routed through the wireless communication module 124 before being transmitted to the external electronic device 20.

[0152] Reference Figure 3 The power button 126 is located on the side of the housing 100 of the wireless charger 10. When the power button 126 is pressed by the user, it contacts a button actuator (not shown) located inside the housing 100. When the power button 126 is pressed, it triggers the processor 110 to start running and execute the methods described below.

[0153] like Figure 3As shown, the electronic components of the wireless charger 10 also include an interface 128 located on the side of the housing 100. The interface 128 can be connected to an external power source 30, such as an alternating current (AC) power source, to provide power to the rechargeable battery 106 and / or other electronic components of the wireless charger 10. In this embodiment, the wireless charger 10 also includes an AC / DC rectifier 130 to convert the input external AC power into direct current (DC).

[0154] The electronic components of the wireless charger 10 also include a power management circuit 132, which is connected to the processor 110, the power source (battery) 106, the transmitter circuit 114, and the interface 128 via the AC / DC rectifier 130. Controlled by the processor 110, the power management circuit 132 draws electrical energy from the power source 106 to power the electronic components of the wireless charger 10, for example, by providing the required power to each transmitting coil 116 via the multiplexer 120. Controlled by the processor 110, and when the interface 128 is connected to the external power source 30, the power management circuit 132 can also draw electrical energy from the external power source 30 and transfer it to the battery 106 to recharge it. In some embodiments, the electrical energy drawn by the power management circuit 132 from the interface 128 is used solely to power the electronic components of the wireless charger 10.

[0155] In some embodiments, the electronic components of the wireless charger 10 may be mounted on a single printed circuit board (PCB) or on multiple interconnected PCBs.

[0156] refer to Figure 11 The processor 110 of the wireless charger 10 is used to execute instructions, such as those stored in memory 112, to perform the methods described below. Implementation of the methods begins only after the user activates the wireless charger 10 by pressing the power button 126. For simplicity, the electronic device 20 can be considered to include a single receiving coil 22.

[0157] The method begins at step 200 by detecting the presence of an electronic device 20 for wireless charging in the charging area 104. This detection is performed using a conventional "ping" technique. For example, each transmitting coil 116 in the coil array 118 is in a "scanning" state and periodically generates a short pulse (called a "ping" signal) through the resonant circuit of the transmitting coil 116 to establish communication with the electronic device 20. The ping signal is transmitted according to the wireless charging standard (i.e., the Qi standard) of the transmitting coil.

[0158] If an electronic device 20 is present, its receiving coil 22 will send a corresponding signal back to the transmitting coil 116 in response to the received ping signal. If the corresponding signal sent by the receiving coil 22 conforms to the wireless charging standard of the transmitting coil 116, the electronic device 20 is considered to be able to charge. Communication between the receiving coil 22 and the transmitting coil 116 is then established in a conventional manner via signal load modulation. Other wireless receivers and foreign objects placed in the charging area 104 will produce responses that do not conform to the wireless charging standard of the transmitting coil 116 and are therefore considered unchargeable. It should be understood that the detection of the electronic device 20 can be performed using digital ping, analog ping, or both.

[0159] In step 202, when the electronic device 20 is in the charging region 104 above the charging surface 102, the processor 110 receives the magnetic field continuously measured by each magnetometer 122 and records and stores it in the memory 112. The processor 110 filters the measurement results to remove measurement results outside the boundary of the charging surface 102.

[0160] The presence of the electronic device 20 in the charging region 104 causes a change in the magnetic field at its location. In step 204, the processor 110 detects the change in the magnetic field based on the measurement results of the magnetometer 122 closest to the electronic device 20 (hereinafter referred to as the "master" magnetometer 122a). Then, in step 206, the processor 110 selects a subset of the transmitting coils 116 associated with the master magnetometer 122a.

[0161] In some cases, the processor 110 can detect changes in the magnetic field based on measurements across two or more magnetometers 122 because the magnetic fields of adjacent transmitting coils 116 overlap. At this point, the processor 110 can determine which magnetometer 122 measured the largest change in the magnetic field and can select the transmitting coil 116 associated with the magnetometer 122 that measured the largest change. The processor 110 can also select all transmitting coils 116 associated with two or more magnetometers 122 based on the change in the magnetic field.

[0162] Subsequently, in step 208, the processor 110 energizes each of the subset of transmitting coils 116 to charge the electronic device 20 by transmitting a predetermined maximum output power. For example, the predetermined maximum output power can be between 20 and 100 watts. In this embodiment, the predetermined maximum output power is approximately 25 watts. When each of the subset of transmitting coils 116 is energized, charging of the electronic device 20 can begin even before the electronic device 20 has come into contact with the charging surface 102 (i.e., when the electronic device 20 is substantially above the charging surface 102). The amount of electricity received by the receiving coil 22 depends on various factors, such as the distance and orientation of the receiving coil 22 relative to the energized transmitting coils 116.

[0163] When the electronic device 20 is placed on or substantially close to the charging surface 102, in step 210, the processor 110 selects a transmitting coil 116 from the subset of transmitting coils 116 based on the measurement results of the main magnetometer 122. This selected transmitting coil 116 is referred to below as a "charging" transmitting coil 116a. In other embodiments, two or more charging transmitting coils 116a may be selected. The selection of the charging transmitting coil 116a begins by calculating the mutual inductance coefficient M between each transmitting coil 116 in the subset of transmitting coils 116 and the receiving coil 22, as described below.

[0164] The self-inductance coefficient L1 of each transmitting coil 116 in the subset of transmitting coils 116 and the self-inductance coefficient L2 of the receiving coil 22 can be obtained by the following formula:

[0165] (1)

[0166] (2)

[0167] in:

[0168] μ o It is the permeability of free space (4π x 10⁻⁶). -7 );

[0169] μ o It is the relative permeability of the iron core of the transmitting coil 116 / receiving coil 22;

[0170] N1 is the number of turns of the transmitting coil 116;

[0171] N2 is the number of turns of the receiving coil 22;

[0172] A is the cross-sectional area of ​​the transmitting coil 116 / receiving coil 22; and

[0173] l is the length of the transmitting coil 116 / receiving coil 22.

[0174] In this embodiment, it is assumed that the receiving coil 22 is the same as or substantially similar to each transmitting coil 116, so the self-inductance L2 of the receiving coil 22 is equal to the self-inductance L1 of each transmitting coil 116. Therefore, the formula for calculating the mutual inductance M between each transmitting coil 116 and the receiving coil 22 in the subset of transmitting coils 116 is:

[0175] (3)

[0176] The formula for the mutual inductance coefficient M above assumes perfect electromagnetic coupling between each transmitting coil 116 in the subset of transmitting coils 116 and the receiving coil 22. However, in reality, the electromagnetic coupling between each transmitting coil 116 in the subset of transmitting coils 116 and the receiving coil 22 is imperfect to some extent. The amount of electromagnetic coupling, also known as the coupling coefficient k, can be expressed as a decimal between 0 and 1, where 0 represents no electromagnetic coupling and 1 represents complete or maximum electromagnetic coupling between each transmitting coil 116 in the subset of transmitting coils 116 and the receiving coil 22. In this embodiment, the formula for calculating the coupling coefficient k of the processor 110 is as follows:

[0177] (4)

[0178] (5)

[0179] (6)

[0180] in:

[0181] k1 is the coupling coefficient of the transmitting coil 116;

[0182] k2 is the coupling coefficient of the receiving coil 22;

[0183] It is the total magnetic flux;

[0184] It is the magnetic flux of the transmitting coil 116; and

[0185] It is the induced magnetic flux of the receiving coil 22.

[0186] Subsequently, the processor 110 calculates the mutual inductance coefficient M based on the coupling coefficient k according to the following formula:

[0187] (7)

[0188] After calculating the mutual inductance coefficient M between each transmitting coil 116 in the subset of transmitting coils 116 and the receiving coil 22, the processor 110 compares the mutual inductance coefficient M with a predetermined inductance range. The predetermined inductance range indicates whether the transmitting coil 116 can supply power to the receiving coil 22. In this embodiment, the predetermined inductance range is between 125 and 860 microhenries. If the mutual inductance coefficient M is not within the predetermined inductance range, it is considered that the transmitting coil 116 cannot supply power to the receiving coil 22, and the processor 110 returns the transmitting coil 116 to the scanning state. However, if the mutual inductance coefficient M is within the predetermined inductance range, it is considered that the transmitting coil 116 can supply power to the receiving coil 22, and the processor 110 selects the transmitting coil 116 as the charging transmitting coil 116a, and adjusts the output power of the charging transmitting coil 116a from the predetermined maximum output power to a first output power P1 for charging the receiving coil 22 in the next step, as described below.

[0189] Figure 12 An example is shown where the electronic device 20 is placed in quadrant Q1 of the charging surface 102. Here, the transmitting coils T1 and T3 are selected as the charging transmitting coil 116a, and the transmitting coils T2 and T4 are in a scanning state.

[0190] In step 212, the processor 110 determines the first output power P1 of the charging transmitting coil 116a based on the measurement results of the main magnetometer 122a. At this point, the processor 110 selects the first output power P1 from a first set of predetermined output powers associated with the mutual inductance coefficient M between the charging transmitting coil 116a and the receiving coil 22. Subsequently, in step 214, the processor 110 energizes the charging transmitting coil 116a to transmit the first output power P1, thereby charging the electronic device 20.

[0191] Table 1 below shows an example of a first predetermined output power group associated with the mutual inductance coefficient M between the charging transmitting coil 116a and the receiving coil 22, wherein the self-inductance coefficient L1 of the charging transmitting coil 116a is 0.000860 Henry. If the calculated result of the mutual inductance coefficient M between the charging transmitting coil 116a and the receiving coil 22 is 0.00052 Henry, then the processor 110 selects 15 watts as the first output power P1 and energizes the charging transmitting coil 116a to transmit 15 watts of power.

[0192]

[0193] Table 1: Examples of the first group of predetermined output power

[0194] As described above, when the electronic device 20 is on the charging surface 102, the electromagnetic coupling between each transmitting coil 116 in the subset of transmitting coils 116 and the receiving coil 22 may be incomplete to some extent. The degree of incomplete electromagnetic coupling may be due to, for example, horizontal misalignment between the receiving coil 22 and each transmitting coil 116 in the subset of transmitting coils 116. Therefore, in another embodiment, in step 210, when the processor 110 calculates the mutual inductance coefficient M between each transmitting coil 116 in the subset of transmitting coils 116 and the receiving coil 22, it may first calculate the misalignment correction value v between each transmitting coil 116 in the subset of transmitting coils 116, as follows:

[0195] (8)

[0196] in:

[0197] d is the distance between the central axes of the transmitting coil 116 and the receiving coil 22; and

[0198] r s It is the radius of the receiving coil 22.

[0199] Then, the processor 110 calculates the mutual inductance coefficient M based on the misalignment correction value v, as follows:

[0200] (9)

[0201] in:

[0202] r p It is the radius of the transmitting coil 116;

[0203] Ψ(m) can be derived from Calculated;

[0204] K(m) can be derived from Calculated;

[0205] E(m) can be derived from Calculated;

[0206] m can be derived from Calculated;

[0207] θ is the angle of the receiving coil 22 relative to the transmitting coil 116;

[0208] α can be derived from Calculated;

[0209] β can be derived from Calculated; and

[0210] c is the vertical distance between the transmitting coil 116 and the receiving coil 22.

[0211] If there is no horizontal misalignment between the receiving coil 22 and the transmitting coil 116, then m can be determined by... Calculated.

[0212] After calculating the mutual inductance coefficient M between each transmitting coil 116 in the subset of transmitting coils 116 and the receiving coil 22, the processor 110 compares the mutual inductance coefficient M with a predetermined inductance range, which in this embodiment is between 125 and 860 microhenries. If the mutual inductance coefficient M is not within the predetermined inductance range, it is considered that the transmitting coil 116 cannot supply power to the receiving coil 22, and the processor 110 returns the transmitting coil 116 to the scanning state. However, if the mutual inductance coefficient M is within the predetermined inductance range, it is considered that the transmitting coil 116 can supply power to the receiving coil 22, and the processor 110 selects the transmitting coil 116 as the charging transmitting coil 116a and adjusts the output power of the charging transmitting coil 116a from the predetermined maximum output power to a first output power P1 for charging the receiving coil 22 in the next step, as described below.

[0213] In step 212, the processor 110 selects a first output power P1 from a first set of predetermined output powers associated with the mutual inductance coefficient M between the charging transmitting coil 116a and the receiving coil 22. Subsequently, in step 214, the processor 110 energizes the charging transmitting coil 116a to transmit the first output power P1, thereby charging the electronic device 20.

[0214] As electrical energy is transferred from the wireless charger 10 to the electronic device 20, the battery level of the electronic device 20 will increase over time. At this time, it may be inefficient for the charging transmitter coil 116a to continue transmitting at the first output power P1. To improve efficiency, the processor 110 dynamically adjusts the transmission power of the charging transmitter coil 116a over time according to the battery level of the electronic device 20, as described below.

[0215] After the charging transmitting coil 116a is energized with a first output power P1, the processor receives power data from the electronic device 20 via the wireless communication module 124 in step 216. In this embodiment, the power data includes the voltage of the battery of the electronic device 20 at any given time. Then, in step 218, the processor 110 calculates the second output power P2 emitted by the charging transmitting coil 116a based on the power data, the first output power P1, and the misalignment correction value v between the charging transmitting coil 116a and the receiving coil 22, as shown below:

[0216] (10)

[0217] in:

[0218] P max can be Calculated;

[0219] ω is the angular frequency of the charging transmitting coil 116a;

[0220] V is the battery voltage of the electronic device 20;

[0221] R L-Pmax can be Calculated;

[0222] Rp is the internal resistance of the charging and transmitting coil 116a; and

[0223] Rs is the internal resistance of the receiving coil 22.

[0224] Then in step 220, the processor energizes the charging transmitter coil 116a to transmit the second output power P2, thereby charging the electronic device 20.

[0225] In the subsequent time period, as described above, the output power of the charging transmitter coil 116a can be continuously and dynamically adjusted based on the battery level of the electronic device 20. This means that the first output power P1 corresponds to the output power immediately preceding the second output power P2 of the charging transmitter coil 116a.

[0226] The above operation can also be performed on electronic devices 20 with two or more receiving coils 22, which may be found in larger wireless charging electronic devices.

[0227] In some embodiments, the coil array 118 may be disposed on a multilayer PCB. Figure 14An array of such coils 118 is shown, in which 36 transmitting coils 116 are etched onto a three-layer PCB. Each layer of the PCB comprises 12 transmitting coils 116, arranged in a grid pattern. Figure 14 In the illustrated embodiment, the top-layer PCB includes a first group of 12 transmitting coils 116a, the middle-layer PCB includes a second group of 12 transmitting coils 116b, and the bottom-layer PCB includes a third group of 12 transmitting coils 116c. Figure 14 As shown, the transmitting coils 116a, 116b, and 116c are laterally offset from each other, thereby completely covering the charging surface 102. This multi-layered coil array 118 significantly reduces the blind zone of the entire charging surface 102 and allows individual transmitting coils 116 to filter simultaneously during power supply and use, thus reducing interference caused by signal noise generated by high-power wireless charging simultaneously transmitting power to multiple devices. Etching the transmitting coils 116a, 116b, and 116c onto the PCB provides a more compact and inexpensive system compared to manufacturing transmitting coils using conventional methods, such as Litz wire structures. Furthermore, the multi-layered coil array 118 allows heat generated by the wireless charger 10 to be dissipated from various layers of the PCB. For example, not all transmitting coils 116 need to be used continuously, meaning that coil layers generating more heat can dissipate heat through other unused transmitting coils 116, thereby improving the overall efficiency of the wireless charger 10.

[0228] In some embodiments, the wireless charger 10 may include only one magnetometer 122. The processor 110 of the wireless charger 10 is used to execute instructions to perform the above-described method operation in a similar manner, except that the step of selecting a subset of the transmitting coils 116 is not performed except that the magnetometer 122 is used as the main magnetometer 122a, because the subset of the transmitting coils 116 is considered as the whole of the transmitting coils 116.

[0229] The embodiments described above offer numerous advantages. For example, the wireless charger 10 is portable and can efficiently and effectively wirelessly charge electronic devices. Taking into account the imperfect electromagnetic coupling between the charging transmitting coil 116a and the receiving coil 22, the wireless charger 10 also provides a continuous charging area, allowing the electronic device 20 to be placed freely on the charging surface 102. Furthermore, the wireless charger 10 can selectively energize the charging transmitting coil 116a while keeping uncoupled or unused transmitting coils 116 in a scanning state. This reduces heat generation in the coil array 118 and interference from overlapping magnetic fields of the uncoupled or unused transmitting coils 116, thus providing more balanced charging.

[0230] Furthermore, the wireless charger 10 can provide initial indiscriminate charging to the electronic device 20 in the charging region 104 above the charging surface 102 by energizing each quadrant of the coil array 118, thereby eliminating the charging delay of the electronic device 20 caused by the arrangement of multiplexers.

[0231] The wireless charger 10 can also charge multiple electronic devices 20 simultaneously. Figure 13 An example of this situation is illustrated. In this example, two electronic devices 20 are placed on the charging surface 102 and located above two quadrants of the coil array 118. While each charging transmitter coil 116a in both quadrants simultaneously charges the electronic device 20 located thereon, the uncoupled or unused transmitter coil 116 remains in a scanning state.

[0232] Furthermore, the processor 110 can dynamically adjust the output power of the charging transmitting coil 116a according to the battery level of the electronic device 20 to ensure efficient power transmission. The wireless charger 10 can also be scaled to accommodate any suitable number of transmitting coils 116, multiplexers 120, and magnetometers 122 corresponding to the size of the housing 100, thus enabling it to charge any suitable number of electronic devices.

[0233] Those skilled in the art will understand that many variations and / or modifications can be made to the above embodiments without departing from the broad overall scope of this disclosure. Therefore, these embodiments should be considered illustrative rather than restrictive in all respects.

Claims

1. A charging method for charging an electronic device having a receiving coil via a wireless charger having a set of transmitting coils and a plurality of magnetic field sensors, each magnetic field sensor being associated with a subset of the transmitting coils, the method comprising: The magnetic field sensor is used to measure the magnetic field of the predetermined charging area; A change in magnetic field was detected based on the measurement results of one of the magnetic field sensors, indicating that the electronic device is in the predetermined charging area; Select a subset of transmitting coils associated with one of the magnetic field sensors; Each transmitting coil in the subset of transmitting coils is energized to transmit a predetermined maximum output power to the receiving coil; Based on the measurement results of one of the magnetic field sensors, a misalignment correction value between each transmitting coil and the receiving coil in the subset of transmitting coils is calculated; Based on their respective misalignment correction values ​​and the measurement value of one of the magnetic field sensors, the mutual inductance coefficient between each transmitting coil and the receiving coil in the subset of transmitting coils is calculated; and The mutual inductance coefficient is compared with a predetermined inductance range to select a transmitting coil from the subset of transmitting coils; Determining a first output power of the transmitting coil based on the measurement results of one of the magnetic field sensors includes: selecting the first output power from a first set of predetermined output powers associated with the mutual inductance coefficient between the transmitting coil and the receiving coil; and The transmitting coil is energized to transmit a first output power to the receiving coil.

2. The charging method according to claim 1, characterized in that: The predetermined inductance range is between 125 and 860 microhenries.

3. The charging method according to claim 1 or 2, after the transmitting coil is energized to transmit the first output power, the method further includes: Receive power data from the electronic device; The second output power is calculated based on the power data, the first output power, and the misalignment correction value between the transmitting coil and the receiving coil. and The transmitting coil is energized to transmit the second output power to the receiving coil.

4. The charging method according to claim 3, characterized in that: The power data includes the voltage of the electronic device's battery.

5. The charging method according to claim 1 or 2, characterized in that: The predetermined maximum output power is between 20 and 100 watts.

6. The charging method according to claim 5, characterized in that: The predetermined maximum output power is approximately 25 watts.

7. A wireless charger for charging an electronic device having a receiving coil, the wireless charger comprising: A housing having a charging surface, and a predetermined charging area defined above the charging surface; A set of transmitting coils; Multiple magnetic field sensors associated with a subset of the transmitting coil; Storage devices are used to store processor-executable instructions; and A processor, connected to the storage device, the transmitting coil, and the magnetic field sensor, is configured to execute stored processor-executable instructions, wherein executing the stored processor-executable instructions causes the processor to: The magnetic field of the predetermined charging area is measured using the magnetic field sensor. A change in magnetic field was detected based on the measurement results of one of the magnetic field sensors, indicating that the electronic device is in the predetermined charging area; Select a subset of transmitting coils associated with one of the magnetic field sensors; Each transmitting coil in the subset of transmitting coils is energized to transmit a predetermined maximum output power to the receiving coil; Based on the measurement results of one of the magnetic field sensors, a misalignment correction value between each transmitting coil and the receiving coil in the subset of transmitting coils is calculated; Based on their respective misalignment correction values ​​and the measurement value of one of the magnetic field sensors, the mutual inductance coefficient between each transmitting coil and the receiving coil in the subset of transmitting coils is calculated; and The mutual inductance coefficient is compared with a predetermined inductance range to select a transmitting coil from the subset of transmitting coils; Based on the measurement results of one of the magnetic field sensors, a first output power of the transmitting coil is determined, including selecting the first output power from a first set of predetermined output powers associated with the mutual inductance coefficient between the transmitting coil and the receiving coil; and The transmitting coil is energized to transmit a first output power to the receiving coil.

8. The wireless charger according to claim 7, characterized in that: The predetermined inductance range is between 125 and 860 microhenries.

9. The wireless charger according to claim 7 or 8, further comprising a wireless communication module connected to the processor, and after executing the stored processor-executable instructions, wherein the processor energizes the one transmitting coil to transmit the first output power, the processor executes the stored processor-executable instructions to cause the processor to: The power data of the electronic device is received through the wireless communication module; The second output power is calculated based on the power data, the first output power, and the misalignment correction value between the transmitting coil and the receiving coil; and The transmitting coil is energized to transmit the second output power to the receiving coil.

10. The wireless charger according to claim 9, characterized in that: The power data includes the voltage of the electronic device's battery.

11. The wireless charger according to claim 7 or 8, characterized in that: The predetermined maximum output power is between 20 and 100 watts.

12. The wireless charger according to claim 11, characterized in that: The predetermined maximum output power is approximately 25 watts.

13. The wireless charger according to claim 7 or 8, characterized in that: Each magnetic field sensor is a triaxial magnetometer.

14. The wireless charger according to claim 7 or 8, further comprising a power source.

15. The wireless charger according to claim 14, characterized in that: The power source is a battery.

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