BR112020010024B1 - WIRELESS CHARGING SYSTEM, TRANSMITTER, RECEIVER AND CHARGING METHOD BASED ON A WIRELESS CHARGING SYSTEM - Google Patents

Abstract

The present invention relates to a wireless charging method and device and a wireless charging system (100). The wireless charging system (100) may comprise a transmitter (10) and a receiver (20). The transmitter (10) comprises a transmission coil (104) and a first series-matched capacitor (103), the transmission coil (104) and the first series-matched capacitor (103) being connected in series to form a first circuit of oscillation, and the first oscillation circuit being used to transmit power to the receiver (20). The receiver (20) comprises a receive coil (201) and a second series-matched capacitor (202), the receive coil (201) and the second series-matched capacitor (202) being connected in series to form a second circuit of oscillation, and the second oscillation circuit being used to receive the power transferred by the first oscillation circuit. The wireless charging system (100) can reduce the power loss in the receiver (20) and improve the charging efficiency of the receiver (20).

Description

FIELD OF TECHNIQUE

[0001] Embodiments of the present invention relate to the field of electronic technologies, and specifically, to a wireless charging method, a device, and a wireless charging system.

FUNDAMENTALS

[0002] Recent years have witnessed a wider application of wireless charging technology for electronic products. Compared with a conventional contact-type electrical power transfer technology, a wireless electrical power transfer technology is safer and more convenient because there is no cable connection between a power source and a load. There are mainly the following various ways to implement wireless electrical energy transfer: electromagnetic radiation, electromagnetic induction, electromagnetic resonance and electric field coupling. Based on efficiency and safety considerations, at present, wireless electrical energy transfer mainly uses electromagnetic induction and electromagnetic resonance for wireless charging.

[0003] Both electromagnetic induction and electromagnetic resonance wireless charging systems perform transfer of electrical energy using electromagnetic induction between a coil in a transmitter and a coil in a receiver. During wireless charging, a transmitter oscillation circuit converts electrical energy into a high-frequency alternating current and supplies the high-frequency alternating current to a primary coil, the primary coil couples the electrical energy to a secondary receiver coil in close proximity , using a magnetic field that generated from high frequency current, and the secondary coil receives the electrical energy, converts the electrical energy into a direct current using a converter circuit, and supplies the direct current to a load for use.

[0004] However, during actual application, if there is a relatively large deviation between the positions of a receiver (e.g., a mobile phone) and a transmitter (e.g., a wireless charging pad) during charging, the Coupling efficiency between the primary coil and the secondary coil is reduced, and therefore the charging efficiency of the receiver is reduced. In addition, due to a reduction in coupling efficiency, the transmitter generates a stronger high-frequency current to generate a stronger magnetic field, and the stronger magnetic field and low charging efficiency cause severe heating of the transmitter and the receiver.

SUMMARY

[0005] Embodiments of the present invention provide a wireless charging method, a device, and a wireless charging system, so as to improve the efficiency of a receiver.

[0006] According to a first aspect, an embodiment of this application provides a wireless charging system, wherein the wireless charging system includes a transmitter and a receiver; The transmitter includes a transmitter coil and a first series matching capacitor, the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit is configured to transfer power to the receiver; and the receiver includes a receiver coil and a second matching capacitor in series, the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp; and a self-inductance applied when the receiver coil receives the power transferred by the first oscillation circuit is Ls, and a capacitance of the second matching capacitor in series is Cs, where , and k is a positive number that meets 0.8 < k < 1.2. The circuit parameters at the transmitter and receiver meet . The wireless charging system can be adjusted to operate at a load-independent point by adjusting a voltage gain to a voltage gain at the load-independent point, such that the voltage gain is independent of a load impedance of the receiver. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0007] In one embodiment, when a voltage gain between a receiver output voltage and a transmitter input voltage is a first voltage gain, the wireless charging system operates at an independent point of charge; the independent load point includes a first operating frequency and a first voltage gain; at the first operating frequency, the first voltage gain is independent of a receiver output load; and the first voltage gain is X, and X is a positive number that meets , or X is a positive number that meets . Regardless of a value of a coupling factor, a voltage gain at the load-independent point is invariably , and the voltage gain is adjusted to be within a range of or within a range of , so that the wireless charging system operates close to the load-independent point, and the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0008] In one embodiment, k is 1, and X is or . When k = 1, Lp * Cp - Ls * Cs = 0. In this case, a voltage gain is regulated to or , and the wireless charging system operates at the independent point of charge, so the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0009] In one embodiment, the transmitter further includes a first voltage regulation module, where the first voltage regulation module is connected to the first oscillation circuit in parallel; and the first voltage regulation module is configured to adjust the voltage gain between the output voltage of the receiver and the input voltage of the transmitter to the first voltage gain by regulating the input voltage of the transmitter.

[0010] In one embodiment, the receiver further includes a second voltage regulation module, where the second voltage regulation module is connected to the second oscillation circuit in parallel; and the second voltage regulation module is configured to adjust the voltage gain between the receiver output voltage and the transmitter input voltage to the first voltage gain by regulating the receiver output voltage.

[0011] According to a second aspect, an embodiment of this application provides a transmitter, wherein the transmitter includes a transmitter coil and a first series matching capacitor, and the transmitter coil is connected to the first series matching capacitor in series. series to form a first oscillation circuit; the first oscillation circuit is configured to transfer power to a receiver; and a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp, where Ls is a self-inductance applied when a receiver coil in the receiver receives the power transferred by the first oscillation circuit, Cs is a capacitance of a second matching capacitor in series in the receiver, and k is a positive number that meets 0.8 < k <1.2; the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit; and the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit. Circuit parameters in the transmitter meet . A wireless charging system can be adjusted to operate at a load-independent point by adjusting a voltage gain to a voltage gain at the load-independent point, such that the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0012] In one embodiment, when a voltage gain between a receiver output voltage and a transmitter input voltage is a first voltage gain, the wireless charging system operates at an independent point of charge; the wireless charging system includes the transmitter and the receiver, the independent charging point includes a first operating frequency and the first voltage gain; at the first operating frequency, the first voltage gain is independent of a receiver output load; and the first voltage gain is X, and X is a positive number that meets , or X is a positive number that meets . Regardless of a value of a coupling factor, a voltage gain at the load-independent point is invariably , and the voltage gain is adjusted to be within a range of or within a range of , so that the wireless charging system operates close to the load-independent point, and the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0013] In one embodiment, k is 1, and X is or . When k = 1, Lp * Cp - Ls * Cs = 0. In this case, a voltage gain is regulated to or , and the wireless charging system operates at the independent point of charge, so the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0014] In one embodiment, the transmitter further includes a voltage regulation module, where the voltage regulation module is connected to the first oscillation circuit in parallel; and the voltage regulation module is configured to adjust the voltage gain between the receiver output voltage and the transmitter input voltage to the first voltage gain by regulating the transmitter input voltage.

[0015] According to a third aspect, an embodiment of this application provides a receiver, wherein the receiver includes a receiver coil and a second matching capacitor in series, the receiver coil is connected to the second matching capacitor in series in series. to form a second oscillation circuit, and the second oscillation circuit is configured to receive power transferred by a transmitter; and a self-inductance applied when the receiver coil receives the power transferred by the transmitter is Ls, and a capacitance of the second matching capacitor in series is Cs, where Lp is a self-inductance applied when a transmitter coil in the transmitter transfers power to the receiver, Cp is a capacitance of a first matching capacitor in series in the transmitter, and k is a positive number that meets 0.8 < k <1.2; the transmitter coil is connected to the first matching capacitor in series to form a first oscillation circuit; and the first oscillation circuit is configured to transfer power to the second oscillation circuit. Circuit parameters in the receiver meet . A wireless charging system can be adjusted to operate at a load-independent point by adjusting a voltage gain to a voltage gain at the load-independent point, such that the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0016] In one embodiment, when a voltage gain between a receiver output voltage and a transmitter input voltage is a first voltage gain, the wireless charging system operates at an independent point of charge; the wireless charging system includes the transmitter and the receiver, the independent charging point includes a first operating frequency and the first voltage gain; at the first operating frequency, the first voltage gain is independent of a receiver output load; and the first voltage gain is X, and X is a positive number that meets , or X is a positive number that meets . Regardless of a value of a coupling factor, a voltage gain at the load-independent point is invariably , and the voltage gain is adjusted to be within a range of or within a range of , so that the wireless charging system operates close to the load-independent point, and the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0017] In one embodiment, k is 1, and X is or . When k = 1, Lp * Cp - Ls * Cs = 0. In this case, a voltage gain is regulated JC /C JLJL to or , and the wireless charging system operates at the independent point of charge, so the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0018] In one embodiment, the receiver further includes a voltage regulation module, where the voltage regulation module is connected to the second oscillation circuit in parallel; and the voltage regulation module is configured to adjust the voltage gain between the receiver output voltage and the transmitter input voltage to the first voltage gain by regulating the receiver output voltage.

[0019] According to a fourth aspect, an embodiment of this application provides a charging method based on a wireless charging system, wherein the wireless charging system includes a transmitter and a receiver; The transmitter includes a transmitter coil and a first series matching capacitor, the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit is configured to transfer power to the receiver; and the receiver includes a receiver coil and a second matching capacitor in series, the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp; a self-inductance applied when the receiver coil receives the power transferred by the first oscillation circuit is Ls, and a capacitance of the second matching capacitor in series is Cs, where , and k is a positive number that meets 0.8 < k <1.2; and the method includes: adjusting, by the transmitter, a voltage gain between a receiver output voltage and a transmitter input voltage for the first voltage gain, where the first voltage gain is X, and X is a positive number that serves , or X is a positive number that meets when the voltage gain between the receiver output voltage and the transmitter input voltage is the first voltage gain, the wireless charging system operates at an independent charge point; the independent load point includes a first operating frequency and a first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; and transfer, through the transmitter, the power to the receiver at the first voltage gain. Regardless of a value of a coupling factor, a voltage gain at the load-independent point . is invariably vps, and the voltage gain is adjusted to be within a range of or within a range of , so that the wireless charging system operates close to the load-independent point, and the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0020] In one embodiment, k is 1, and X is or . When k = 1, Lp * Cp - Ls * Cs = 0. In this case, a voltage gain is regulated to or , and the wireless charging system operates at the independent point of charge, so the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0021] In one embodiment, the adjustment, by the transmitter, of a voltage gain between a receiver output voltage and a transmitter input voltage for the first voltage gain includes: receiving, by the transmitter, information sent by the receiver and which indicate a first output voltage, wherein the first output voltage is an expected output voltage of the receiver; and adjusting, by the transmitter, the input voltage of the transmitter to a first input voltage based on the first output voltage and the first voltage gain.

[0022] In one embodiment, prior to adjusting, by the transmitter, a voltage gain between a receiver output voltage and a transmitter input voltage for the first voltage gain, the method further includes: receiving, by the transmitter, the information sent by the receiver and indicating Cs and/or the information sent by the receiver and indicating Ls, where Cs and Ls are used by the transmitter to determine the first voltage gain; and/or receive, through the transmitter, the information sent by the receiver and which indicates the first voltage gain.

[0023] According to a fifth aspect, an embodiment of this application provides a charging method based on a wireless charging system, wherein the wireless charging system includes a transmitter and a receiver; The transmitter includes a transmitter coil and a first series matching capacitor, the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit is configured to transfer power to the receiver; and the receiver includes a receiver coil and a second matching capacitor in series, the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp; a self-inductance applied when the receiver coil receives the power transferred by the first oscillation circuit is Ls, and a capacitance of the second matching capacitor in series is Cs, where , and k is a positive number that meets 0.8 < k <1.2; and the method includes: sending, by the receiver to the transmitter, information indicating a first output voltage, where the first output voltage is an expected output voltage of the receiver, and the first output voltage is used by the transmitter to adjust a transmitter input voltage to a first input voltage based on the first output voltage and a first voltage gain, where the first voltage gain is , or X is a positive number that meets when a voltage gain between a receiver output voltage and a transmitter input voltage is the first voltage gain, the wireless charging system operates at a charge-independent point; the independent load point includes a first operating frequency and a first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; It is

[0024] receive, by the receiver, the power transferred by the transmitter in the first voltage gain. Regardless of a value of a coupling factor, a voltage gain at the load-independent point is invariably , and the voltage gain is adjusted to be within a range of or within a range of , so that the wireless charging system operates close to the load-independent point, and the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0025] According to a sixth aspect, an embodiment of this application provides a charging method based on a wireless charging system, wherein the wireless charging system includes a transmitter and a receiver; The transmitter includes a transmitter coil and a first series matching capacitor, the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit is configured to transfer power to the receiver; and the receiver includes a receiver coil and a second matching capacitor in series, the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp; a self-inductance applied when the receiver coil receives the power transferred by the first oscillation circuit is Ls, and a capacitance of the second matching capacitor in series is Cs, where , and k is a positive number that meets 0.8 < k <1.2; and the method includes: adjusting, by the receiver, a voltage gain between a receiver output voltage and a transmitter input voltage for the first voltage gain, where the first voltage gain is X, and X is a positive number that serves , or X is a positive number that meets when the voltage gain between the receiver output voltage and the transmitter input voltage is the first voltage gain, the wireless charging system operates at an independent charge point; the independent load point includes a first operating frequency and a first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; and receive, through the receiver, the power transferred by the transmitter in the first voltage gain. Regardless of a value of a coupling factor, a voltage gain at the load-independent point is invariably , and the voltage gain is adjusted to be within a range of or within a range of , so that the wireless charging system operates close to the load-independent point, and the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0026] In one embodiment, k is 1, and X is or . When k = 1, Lp * Cp - Ls * Cs = 0. In this case, a voltage gain is regulated to or , and the wireless charging system operates at the independent point of charge, so the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0027] In one embodiment, the adjustment, by the receiver, of a voltage gain between a receiver output voltage and a transmitter input voltage for the first voltage gain includes: receiving, by the receiver, information sent by the transmitter and which indicate a first input voltage, wherein the first input voltage is a transmitter input voltage; and adjusting, by the receiver, the output voltage of the receiver to a first output voltage based on the first input voltage and the first voltage gain.

[0028] In one embodiment, prior to adjusting, by the receiver, a voltage gain between a receiver output voltage and a transmitter input voltage for the first voltage gain, the method further includes: receiving, by the receiver, the information sent by the transmitter and indicating Cp and/or the information sent by the transmitter and indicating Lp, where Cp and Lp are used by the receiver to determine the first voltage gain; and/or receive, by the receiver, the information sent by the transmitter and which indicates the first voltage gain.

[0029] According to a seventh aspect, an embodiment of this application provides a charging method based on a wireless charging system, wherein the wireless charging system includes a transmitter and a receiver; The transmitter includes a transmitter coil and a first series matching capacitor, the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit is configured to transfer power to the receiver; and the receiver includes a receiver coil and a second matching capacitor in series, the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp; a self-inductance applied when the receiver coil receives the power transferred by the first oscillation circuit is Ls, and a capacitance of the second matching capacitor in series is Cs, where , and k is a positive number that meets 0.8 < k <1.2; and the method includes: sending, by the transmitter to the receiver, information indicating a first input voltage, wherein the first input voltage is an input voltage of the transmitter; and the first input voltage is used by the receiver to adjust an output voltage of the receiver to a first output voltage based on the first input voltage and a first voltage gain, where the first voltage gain is a positive number that meets , or X is a positive number that meets when a voltage gain between the receiver output voltage and the transmitter input voltage is the first voltage gain, the wireless charging system operates at a charge-independent point; the independent load point includes a first operating frequency and a first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; and transfer, through the transmitter, the power to the receiver at the first voltage gain. Regardless of a value of a coupling factor, a voltage gain at the load-independent point is invariably , and the voltage gain is adjusted to be within a range of or within a range of , so that the wireless charging system operates close to the load-independent point, and the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0030] According to an eighth aspect, an embodiment of this application provides a charging method based on a wireless charging system, wherein the wireless charging system includes a transmitter and a receiver; The transmitter includes a transmitter coil and a first series matching capacitor, the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit is configured to transfer power to the receiver; The receiver includes a receiver coil and a second matching capacitor in series, the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and the method includes:

[0031] finding, by the transmitter of a first mapping table, a first load-independent point that corresponds to a first degree of coupling; or

[0032] receive, by the transmitter, the information sent by the receiver and which indicates a first charge-independent point, where the first charge-independent point is a first charge-independent point that corresponds to a first degree of coupling and found by the receiver of a first mapping table, where

[0033] the first independent point of load includes a first voltage gain, and the first degree of coupling is a degree of coupling between the coil in the transmitter and the coil in the receiver; the first mapping table includes at least one degree of coupling and a load-independent point that corresponds to each of the at least one degree of coupling, and the load-independent point is a combination of a voltage gain and an operating frequency ; and at an operating frequency at a load-independent point corresponding to each degree of coupling, a voltage gain at the load-independent point corresponding to the degree of coupling is independent of an output load of the receiver;

[0034] adjusting, by the transmitter, a voltage gain between a receiver output voltage and a transmitter input voltage for the first voltage gain; It is

[0035] transfer, through the transmitter, the power to the receiver at the first voltage gain.

[0036] The load independent point is found from the first mapping table using the degree of coupling. The wireless charging system can be adjusted to operate at a load-independent point by adjusting a voltage gain to a voltage gain at the load-independent point, such that the voltage gain is independent of a receiver load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved. Circuit parameters of the transmitter and receiver do not need to be limited, and the generality of the transmitter and receiver is improved.

[0037] In one embodiment, the adjustment, by the transmitter, of a voltage gain between a receiver output voltage and a transmitter input voltage for the first voltage gain includes: receiving, by the transmitter, information sent by the receiver and which indicate a first output voltage, wherein the first output voltage is an expected output voltage of the receiver; and adjusting, by the transmitter, the input voltage of the transmitter to a first input voltage based on the first output voltage and the first voltage gain.

[0038] In one embodiment, prior to adjusting, by the transmitter, a voltage gain between a receiver output voltage and a transmitter input voltage for the first voltage gain, the method further includes: receiving, by the transmitter, the information sent by the receiver and indicating Cs and/or the information sent by the receiver and indicating Ls, where Cs and Ls are used by the transmitter to determine the first voltage gain; and/or receive, through the transmitter, the information sent by the receiver and which indicates the first voltage gain.

[0039] According to a ninth aspect, an embodiment of this application provides a charging method based on a wireless charging system, wherein the wireless charging system includes a transmitter and a receiver; The transmitter includes a transmitter coil and a first series matching capacitor, the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit is configured to transfer power to the receiver; The receiver includes a receiver coil and a second matching capacitor in series, the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and the method includes:

[0040] send, by the receiver to the transmitter, information indicating a first output voltage, where the first output voltage is an expected output voltage of the receiver, and the first output voltage is used by the transmitter to adjust a voltage of transmitter input to a first input voltage based on the first output voltage and a first voltage gain, where the first voltage gain is included in a first load-independent point corresponding to a first degree of coupling and encountered by the transmitter of a first mapping table; or the first voltage gain is included in a first load-independent point corresponding to a first degree of coupling and found by the receiver of a first mapping table; and the first charge-independent point is added to the information indicating the first charge-independent point, and then sent by the receiver to the transmitter, where

[0041] the first degree of coupling is a degree of coupling between the transmitter coil in the transmitter and the receiver coil in the receiver; the first mapping table includes at least one degree of coupling and a load-independent point that corresponds to each of the at least one degree of coupling, and the load-independent point is a combination of a voltage gain and an operating frequency ; and at an operating frequency at a load-independent point corresponding to each degree of coupling, a voltage gain at the load-independent point corresponding to the degree of coupling is independent of an output load of the receiver; It is

[0042] receive, through the receiver, the power transferred by the transmitter in the first voltage gain.

[0043] The load independent point is found from the first mapping table using the degree of coupling. The wireless charging system can be adjusted to operate at a load-independent point by adjusting a voltage gain to a voltage gain at the load-independent point, such that the voltage gain is independent of a receiver load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved. Circuit parameters of the transmitter and receiver do not need to be limited, and the generality of the transmitter and receiver is improved.

[0044] According to a tenth aspect, an embodiment of this application provides a charging method based on a wireless charging system, wherein the wireless charging system includes a transmitter and a receiver; The transmitter includes a transmitter coil and a first series matching capacitor, the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit is configured to transfer power to the receiver; The receiver includes a receiver coil and a second matching capacitor in series, the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and the method includes:

[0045] finding, by the receiver of a first mapping table, a first charge-independent point that corresponds to a first degree of coupling; or

[0046] receive, by the receiver, the information sent by the transmitter and which indicates a first charge-independent point, where the first charge-independent point is a first charge-independent point that corresponds to a first degree of coupling and found by the transmitter of a first mapping table, where

[0047] the first independent point of load includes a first voltage gain, and the first degree of coupling is a degree of coupling between the transmitter coil in the transmitter and the receiver coil in the receiver; the first mapping table includes at least one degree of coupling and a load-independent point that corresponds to each of the at least one degree of coupling, and the load-independent point is a combination of a voltage gain and an operating frequency ; and at an operating frequency at a load-independent point corresponding to each degree of coupling, a voltage gain at the load-independent point corresponding to the degree of coupling is independent of an output load of the receiver;

[0048] adjusting, by the receiver, a voltage gain between an output voltage of the receiver and an input voltage of the transmitter for the first voltage gain; It is

[0049] receive, through the receiver, the power transferred by the transmitter in the first voltage gain.

[0050] The load independent point is found from the first mapping table using the degree of coupling. The wireless charging system can be adjusted to operate at a load-independent point by adjusting a voltage gain to a voltage gain at the load-independent point, such that the voltage gain is independent of a receiver load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved. Circuit parameters of the transmitter and receiver do not need to be limited, and the generality of the transmitter and receiver is improved.

[0051] In one embodiment, the adjustment, by the receiver, of a voltage gain between a receiver output voltage and a transmitter input voltage for the first voltage gain includes: receiving, by the receiver, information sent by the transmitter and which indicate a first input voltage, wherein the first input voltage is a transmitter input voltage; and adjusting, by the receiver, the output voltage of the receiver to a first output voltage based on the first input voltage and the first voltage gain.

[0052] In one embodiment, prior to adjusting, by the receiver, a voltage gain between a receiver output voltage and a transmitter input voltage for the first voltage gain, the method further includes: receiving, by the receiver, the information sent by the transmitter and indicating Cp and/or the information sent by the transmitter and indicating Lp, where Cp and Lp are used by the receiver to determine the first voltage gain; and/or receive, by the receiver, the information sent by the transmitter and which indicates the first voltage gain.

[0053] According to an eleventh aspect, an embodiment of this application provides a charging method based on a wireless charging system, wherein the wireless charging system includes a transmitter and a receiver; The transmitter includes a transmitter coil and a first series matching capacitor, the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit is configured to transfer power to the receiver; The receiver includes a receiver coil and a second matching capacitor in series, the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and the method includes:

[0054] send, by the transmitter to the receiver, information indicating a first input voltage, where the first input voltage is an input voltage of the transmitter; the first input voltage is used by the receiver to adjust an output voltage of the receiver to a first output voltage based on the first input voltage and a first voltage gain; the first voltage gain is included in a first load independent point corresponding to a first degree of coupling and found by the transmitter from a first mapping table; or the first voltage gain is included in a first load-independent point corresponding to a first degree of coupling and found by the receiver of a first mapping table; and the first charge-independent point is added to the information indicating the first charge-independent point, and then sent by the receiver to the transmitter, where

[0055] the first degree of coupling is a degree of coupling between the transmitter coil in the transmitter and the receiver coil in the receiver; the first mapping table includes at least one degree of coupling and a load-independent point that corresponds to each of the at least one degree of coupling, and the load-independent point is a combination of a voltage gain and an operating frequency ; and at an operating frequency at a load-independent point corresponding to each degree of coupling, a voltage gain at the load-independent point corresponding to the degree of coupling is independent of an output load of the receiver; It is

[0056] transfer, through the transmitter, the power to the receiver at the first voltage gain.

[0057] The load independent point is found from the first mapping table using the degree of coupling. The wireless charging system can be adjusted to operate at a load-independent point by adjusting a voltage gain to a voltage gain at the load-independent point, such that the voltage gain is independent of a receiver load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved. Circuit parameters of the transmitter and receiver do not need to be limited, and the generality of the transmitter and receiver is improved.

[0058] According to a twelfth aspect, an embodiment of this application provides a transmitter, wherein the transmitter includes a module or unit configured to perform the wireless charging method provided in the fourth aspect or any possible implementation of the fourth aspect.

[0059] According to a thirteenth aspect, an embodiment of this application provides a receiver, wherein the receiver includes a module or unit configured to perform the wireless charging method provided in the fifth aspect.

[0060] According to a fourteenth aspect, an embodiment of this application provides a receiver, wherein the receiver includes a module or unit configured to perform the wireless charging method provided in the sixth aspect or any possible implementation of the sixth aspect.

[0061] According to a fifteenth aspect, an embodiment of this application provides a transmitter, wherein the transmitter includes a module or unit configured to perform the wireless charging method provided in the seventh aspect.

[0062] According to a sixteenth aspect, an embodiment of this application provides a transmitter, wherein the transmitter includes a module or a unit configured to perform the wireless charging method provided in the eighth aspect or any possible implementation of the eighth aspect.

[0063] According to a seventeenth aspect, an embodiment of this application provides a receiver, wherein the receiver includes a module or unit configured to perform the wireless charging method provided in the ninth aspect or any possible implementation of the ninth aspect.

[0064] According to an eighteenth aspect, an embodiment of this application provides a receiver, wherein the receiver includes a module or unit configured to perform the wireless charging method provided in the tenth aspect or any possible implementation of the tenth aspect.

[0065] According to a nineteenth aspect, an embodiment of this application provides a transmitter, wherein the transmitter includes a module or unit configured to perform the wireless charging method provided in the eleventh aspect or any possible implementation of the eleventh aspect. .

[0066] According to a twentieth aspect, an embodiment of this application provides a transmitter, which includes: a processor, a memory, a transceiver, and a bus, where the processor, the transceiver, and the memory communicate with each other using the bus; the transceiver is configured to receive and send data; memory is configured to store an instruction; and the processor is configured to invoke the instruction in memory to execute the wireless charging method provided in the fourth aspect or any possible implementation of the fourth aspect.

[0067] According to a twenty-first aspect, an embodiment of this application provides a receiver, which includes: a processor, a memory, a transceiver, and a bus, where the processor, the transceiver, and the memory communicate with each other using the bus; the transceiver is configured to receive and send data; memory is configured to store an instruction; and the processor is configured to invoke the instruction in memory to execute the wireless charging method provided in the fifth aspect or any possible implementation of the fifth aspect.

[0068] According to a twenty-second aspect, an embodiment of this application provides a receiver, which includes: a processor, a memory, a transceiver, and a bus, where the processor, the transceiver, and the memory communicate with each other using the bus; the transceiver is configured to receive and send data; memory is configured to store an instruction; and the processor is configured to invoke the instruction in memory to execute the wireless charging method provided in the sixth aspect or any possible implementation of the sixth aspect.

[0069] According to a twenty-third aspect, an embodiment of this application provides a transmitter, which includes: a processor, a memory, a transceiver, and a bus, where the processor, the transceiver, and the memory communicate with each other using the bus; the transceiver is configured to receive and send data; memory is configured to store an instruction; and the processor is configured to invoke the instruction in memory to execute the wireless charging method provided in the seventh aspect or any possible implementation of the seventh aspect.

[0070] According to a twenty-fourth aspect, an embodiment of this application provides a transmitter, which includes: a processor, a memory, a transceiver, and a bus, where the processor, the transceiver, and the memory communicate with each other using the bus; the transceiver is configured to receive and send data; memory is configured to store an instruction; and the processor is configured to invoke the instruction in memory to execute the wireless charging method provided in the eighth aspect or any possible implementation of the eighth aspect.

[0071] According to a twenty-fifth aspect, an embodiment of this application provides a receiver, which includes: a processor, a memory, a transceiver, and a bus, where the processor, the transceiver, and the memory communicate with each other using the bus; the transceiver is configured to receive and send data; memory is configured to store an instruction; and the processor is configured to invoke the instruction in memory to execute the wireless charging method provided in the ninth aspect or any possible implementation of the ninth aspect.

[0072] According to a twenty-sixth aspect, an embodiment of this application provides a receiver, which includes: a processor, a memory, a transceiver, and a bus, where the processor, the transceiver, and the memory communicate with each other using the bus; the transceiver is configured to receive and send data; memory is configured to store an instruction; and the processor is configured to invoke the instruction in memory to execute the wireless charging method provided in the tenth aspect or any possible implementation of the tenth aspect.

[0073] According to a twenty-seventh aspect, an embodiment of this application provides a transmitter, which includes: a processor, a memory, a transceiver, and a bus, where the processor, the transceiver, and the memory communicate with each other using the bus; the transceiver is configured to receive and send data; memory is configured to store an instruction; and the processor is configured to invoke the instruction in memory to execute the wireless charging method provided in the eleventh aspect or any possible implementation of the eleventh aspect.

[0074] According to a twenty-eighth aspect, an embodiment of this application provides a computer-readable storage medium, wherein the storage medium includes an instruction, and when the instruction is executed at a transmitter, the transmitter executes the loading method wireless provided in the fourth aspect or any possible implementation of the fourth aspect.

[0075] According to a twenty-ninth aspect, an embodiment of this application provides a computer-readable storage medium, wherein the storage medium includes an instruction, and when the instruction is executed at a receiver, the receiver executes the load method wireless provided in the fifth aspect or any possible implementation of the fifth aspect.

[0076] According to a thirtieth aspect, an embodiment of this application provides a computer-readable storage medium, wherein the storage medium includes an instruction, and when the instruction is executed at a receiver, the receiver executes the loading method without thread provided in the sixth aspect or any possible implementation of the sixth aspect.

[0077] According to a thirty-first aspect, an embodiment of this application provides a computer-readable storage medium, wherein the storage medium includes an instruction, and when the instruction is executed at a transmitter, the transmitter executes the loading method wireless provided in the seventh aspect or any possible implementation of the seventh aspect.

[0078] According to a thirty-second aspect, an embodiment of this application provides a computer-readable storage medium, wherein the storage medium includes an instruction, and when the instruction is executed at a transmitter, the transmitter executes the loading method wireless provided in the eighth aspect or any possible implementation of the eighth aspect.

[0079] According to a thirty-third aspect, an embodiment of this application provides a computer-readable storage medium, wherein the storage medium includes an instruction, and when the instruction is executed at a receiver, the receiver executes the load method wireless provided in the ninth aspect or any possible implementation of the ninth aspect.

[0080] According to a thirty-fourth aspect, an embodiment of this application provides a computer-readable storage medium, wherein the storage medium includes an instruction, and when the instruction is executed at a receiver, the receiver executes the load method wireless provided in the tenth aspect or any possible implementation of the tenth aspect.

[0081] According to a thirty-fifth aspect, an embodiment of this application provides a computer-readable storage medium, wherein the storage medium includes an instruction, and when the instruction is executed at a transmitter, the transmitter executes the loading method wireless provided in the eleventh aspect or any possible implementation of the eleventh aspect.

[0082] According to a thirty-sixth aspect, an embodiment of this application provides a computer program, wherein the computer program includes an instruction, and when the instruction is executed on a transmitter, the transmitter performs the provided wireless charging method. in the fourth aspect or any possible implementation of the fourth aspect.

[0083] According to a thirty-seventh aspect, an embodiment of this application provides a computer program, wherein the computer program includes an instruction, and when the instruction is executed on a receiver, the receiver executes the provided wireless charging method. in the fifth aspect.

[0084] According to a thirty-eighth aspect, an embodiment of this application provides a computer program, wherein the computer program includes an instruction, and when the instruction is executed on a receiver, the receiver executes the provided wireless charging method. in the sixth aspect or any possible implementation of the sixth aspect.

[0085] According to a thirty-ninth aspect, an embodiment of this application provides a computer program, wherein the computer program includes an instruction, and when the instruction is executed on a transmitter, the transmitter performs the provided wireless charging method. in the seventh aspect or any possible implementation of the seventh aspect.

[0086] According to a fortieth aspect, an embodiment of this application provides a computer program, wherein the computer program includes an instruction, and when the instruction is executed on a transmitter, the transmitter executes the wireless charging method provided in the eighth aspect or any possible implementation of the eighth aspect.

[0087] According to a forty-first aspect, an embodiment of this application provides a computer program, wherein the computer program includes an instruction, and when the instruction is executed on a receiver, the receiver performs the provided wireless charging method. in the ninth aspect.

[0088] According to a forty-second aspect, an embodiment of this application provides a computer program, wherein the computer program includes an instruction, and when the instruction is executed on a receiver, the receiver performs the provided wireless charging method. in the tenth aspect or any possible implementation of the tenth aspect.

[0089] According to a forty-third aspect, an embodiment of this application provides a computer program, wherein the computer program includes an instruction, and when the instruction is executed on a transmitter, the transmitter performs the provided wireless charging method. in the eleventh aspect or any possible implementation of the eleventh aspect.

[0090] According to a forty-fourth aspect, an embodiment of this application provides a transmitter chip product, for carrying out the method in the fourth aspect or any possible implementation of the fourth aspect.

[0091] According to a forty-fifth aspect, an embodiment of this application provides a receiver chip product, for carrying out the method in the fifth aspect or any possible implementation of the fifth aspect.

[0092] According to a forty-sixth aspect, an embodiment of this application provides a chip product of a receiver, for carrying out the method in the sixth aspect or any possible implementation of the sixth aspect.

[0093] According to a forty-seventh aspect, an embodiment of this application provides a transmitter chip product, for carrying out the method in the seventh aspect or any possible implementation of the seventh aspect.

[0094] According to a forty-eighth aspect, an embodiment of this application provides a transmitter chip product, for carrying out the method in the eighth aspect or any possible implementation of the eighth aspect.

[0095] According to a forty-ninth aspect, an embodiment of this application provides a receiver chip product, for carrying out the method in the ninth aspect or any possible implementation of the ninth aspect.

[0096] According to a fiftieth aspect, an embodiment of this application provides a receiver chip product, for carrying out the method in the tenth aspect or any possible implementation of the tenth aspect.

[0097] According to a fifty-first aspect, an embodiment of this application provides a transmitter chip product, for carrying out the method in the eleventh aspect or any possible implementation of the eleventh aspect.

[0098] In embodiments of this application, the wireless charging system can be adjusted to operate at a load-independent point by adjusting a voltage gain to a voltage gain at the load-independent point, such that the voltage gain is independent of a receiver load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, a loss of electrical power from a voltage regulator module in the receiver can be reduced, and the charging efficiency of the receiver can be improved.

BRIEF DESCRIPTION OF DRAWINGS

[0099] To describe the technical solutions in the embodiments of the present invention or in the fundamentals more clearly, the following describes the accompanying drawings required in the embodiments of the present invention or in the fundamentals.

[0100] Figure 1 is a schematic architectural diagram of a wireless charging system to which an embodiment of this application refers;

[0101] Figure 2 is a schematic diagram of a position offset between a transmitter and a receiver in accordance with an embodiment of this application;

[0102] Figure 3 shows an equivalent circuit model of a wireless charging system in accordance with an embodiment of this application;

[0103] Figure 4 is a schematic diagram of a relationship between a voltage gain and an operating frequency according to an embodiment of this application;

[0104] Figure 5 shows another equivalent circuit model of a wireless charging system in accordance with an embodiment of this application;

[0105] Figure 6 is a schematic diagram of another relationship between a voltage gain and an operating frequency in accordance with an embodiment of this application;

[0106] Figure 7 is a schematic diagram of yet another relationship between a voltage gain and an operating frequency in accordance with an embodiment of this application;

[0107] Figure 8 is a schematic architectural diagram of another wireless charging system in accordance with an embodiment of this application;

[0108] Figure 9 is a schematic flowchart of a wireless charging method in accordance with an embodiment of this application;

[0109] Figure 10 is a schematic structural diagram of yet another wireless charging system in accordance with an embodiment of this application;

[0110] Figure 11 is a schematic flowchart of another wireless charging method in accordance with an embodiment of this application;

[0111] Figure 12 is a schematic flowchart of yet another wireless charging method in accordance with an embodiment of this application;

[0112] Figure 13 is a schematic flowchart of yet another wireless charging method in accordance with an embodiment of this application;

[0113] Figure 14 shows an electrical energy conversion efficiency test result according to an embodiment of this application;

[0114] Figure 15 shows another electrical energy conversion efficiency test result according to an embodiment of this application;

[0115] Figure 16 is a schematic diagram of a test of a voltage and a current in accordance with an embodiment of this application;

[0116] Figure 17 is a schematic structural diagram of a wireless charging system 100 in accordance with an embodiment of this application;

[0117] Figure 18 is a schematic structural diagram of another wireless charging system 100 in accordance with an embodiment of this application;

[0118] Figure 19 is a schematic structural diagram of yet another wireless charging system 100 in accordance with an embodiment of this application; It is

[0119] Figure 20 is a schematic structural diagram of yet another wireless charging system 100 in accordance with an embodiment of this application.

DESCRIPTION OF MODALITIES

[0120] The following describes embodiments of the present invention with reference to the accompanying drawings in embodiments of the present invention. Terms used in the embodiments of this application are only used to explain specific embodiments of this application, and are not intended to limit this application.

[0121] Embodiments of this application describe a wireless charging method and device, so as to improve the charging efficiency of a receiver. Detailed descriptions are provided separately below.

[0122] Figure 1 is a schematic architectural diagram of a wireless charging system to which an embodiment of this application refers. As shown in Figure 1, the wireless charging system 100 includes a transmitter 10 and a receiver 20. The transmitter 10 can transfer power to the receiver 20 to wirelessly charge the receiver 20.

[0123] The receiver 20 may be a mobile user equipment (UE), an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote station, a remote terminal, a user or a user agent. The access terminal may be a cell phone, a portable device that has a wireless communication function, a computing device or an in-vehicle device, a wearable device, a terminal in a 5G system, or a terminal in a land mobile network future developed public network (public land mobile network, PLMN), or similar. Specifically, the receiver 20 may be a mobile phone, a Tablet computer (Pad), a computer that has a wireless transceiver function, a virtual reality (VR) terminal device, a augmented reality terminal (AR), a wireless terminal in an industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home ), or similar. Alternatively, the receiver 20 may be a wireless charging electric vehicle or white goods, for example, a cable-free television, a wireless charging soy milk maker, a wireless charging vacuum cleaning robot, or a multi-rotor drone.

[0124] A mode of data communication between the transmitter 10 and the receiver 20 may be wireless communication, and may specifically be in-band communication, Bluetooth communication, Zigbee communication, WiFi communication, or the like.

[0125] The transmitter 10 may include a DC power source 101, a DC/AC conversion module 102, a series matching capacitor (whose capacitance is Cp) 103, a transmitter coil 104, and a control module 105 The receiver 20 may include a receiver coil 201, a series matching capacitor (whose capacitance is Cs) 202, an AC/DC conversion module 203, a voltage regulator module 204, an output load 205, a . modulation module 206, and a control module 207.

[0126] Specifically, as shown in Figure 1, the DC power source 101 is configured to supply charging power. The DC/AC conversion module 102 is connected to the DC power source 101, and is configured to: receive a direct current that is emitted by the DC power source 101, convert the received direct current into an alternating current, and output the current alternate. The series matching capacitor (whose capacitance is Cp) 103 and the transmitter coil 104 are connected to form an oscillation circuit. The oscillation circuit is connected to the DC/AC conversion module 102, and is configured to receive the alternating current that is emitted by the DC/AC conversion module 102 and supply the alternating current to the transmitter coil 104. The power of the coil transmitter coil 104 is transferred to the receiver coil 201 under coupling of the transmitter coil 104 and the receiver coil 201. The control module 105 may be separately connected to the DC power source 101, the DC/AC conversion module 102, the series matching capacitor (whose capacitance is Cp) 103, and the transmitter coil 104, and is configured to exchange a control parameter with each module, to implement control over each module.

[0127] The DC/AC conversion module 102 may be a full-bridge inverter circuit, or it may be a half-bridge inverter circuit, or it may be another inverter circuit that converts direct current into an alternating current. This is not limited to this embodiment of this application.

[0128] As shown in Figure 1, the receiver coil 201 is connected to the series matching capacitor (whose capacitance is Cs) 202, to form an oscillation circuit on one side of the receiver 20. The receiver coil 201 receives, Through coil coupling, the power transferred by the transmitter coil 104, and converts the power into an alternating current using the oscillation circuit. The AC/DC conversion module 203 is connected to the oscillation circuit, and is configured to receive the alternating current that is emitted by the oscillation circuit, and rectify the alternating current to obtain an output voltage Vrect. The voltage regulator module 204 is connected to the AC/DC conversion module 203, and is configured to eliminate a fluctuation in the output voltage Vrect of the AC/DC conversion module 203, to output a stable voltage V2. The output load 205 is connected to the voltage regulator module 204, and is configured to receive the supply voltage V2 that is output by the voltage regulator module 204. The modulation module 206 is configured to implement in-band communication with the transmitter 10.

[0129] Specifically, as shown in Figure 1, the modulation module 206 may utilize switched capacitor modulation and/or switched resistor modulation. The receiver 20 controls the connection and disconnection of a switch S1 and/or a switch S2, to allow a capacitor C1 and/or a resistor R1 to be connected to a receiver circuit or not connected to a receiver circuit, so that a voltage or a current in the receiver coil 201 in the receiver 20 is changed, and a voltage or a current in the transmitter 10 is changed. The transmitter 10 collects the voltage or current and can obtain, through analysis after demodulation processing, a communication signal modulated by the receiver 20. The control module 207 can be separately connected to the receiver coil 201, the matching capacitor (whose capacitance is Cs) 202, the AC/DC conversion module 203, the voltage regulator module 204, the output load 205, and the modulation module 206, and is configured to exchange a control parameter with each module, to implement control over each module.

[0130] The AC/DC conversion module 102 may be a diode full-bridge rectifier circuit, or it may be a switching transistor synchronous rectifier circuit, or it may be half-bridge rectifier circuit, or it may be another rectifier circuit that converts an alternating current into a direct current. This is not limited to this embodiment of this application.

[0131] During In-Band communication, connection of modulation capacitor C1 and connection of modulation resistor R1 may cause fluctuation in a load in a receiver circuit 20. For example, if a load jumps occurs in the receiver 20, an operating frequency needs to be regulated to maintain a constant receiver output voltage in accordance with the Wireless Power Consortium (WPC) standard. In this process, a control parameter to regulate the operating frequency needs to be transmitted through in-band communication. During in-band communication, in-band communication may affect a receiver's output load. For example, in a capacitor modulation mode, if the AC/DC conversion module 203 is a full-wave rectifier diode bridge, the connection of the modulation capacitor C1 is equivalent to an increase in capacitance in two full-wave rectifier tubes. a rectifier bridge. When a polarity of a current flowing to the rectifier bridge changes, the modulation capacitor C1 can be charged or discharged, which is equivalent to a charge disturbance and can affect V1.

[0132] Connecting and disconnecting the modulation capacitor and/or modulation resistor causes V1 to change at a relatively high amplitude. V2 which is output by the voltage regulator module 204 is a stable direct current voltage. A portion of the voltage V1 that exceeds V2 is consumed by the voltage regulator module 204, and becomes the power consumption of the voltage regulator module 204, increasing an electrical power loss of the receiver 20.

[0133] When there is a deviation between positions in which the receiver 20 and transmitter 10 are placed, the transmitter coil 104 and the receiver coil 201 do not directly face each other, and misalignment exists. A load jump can cause a fluctuation in the output voltage V1. Furthermore, in-band communication may cause a jump of the output voltage V1, the voltage regulator module 204 operates frequently, a loss of electrical power from the voltage regulator module 204 is increased, and the charging efficiency is reduced.

[0134] Based on the schematic architectural diagram of the wireless charging system in Figure 1, this application provides a wireless charging method, so that the output voltage fluctuation caused by a load jump can be reduced, and a Output voltage jump caused by in-band communication can be reduced. Therefore, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of a receiver can be improved.

[0135] A main inventive principle of this application may include: enabling the wireless charging system to operate at an independent point of charge through voltage regulation and operating frequency regulation, so that a voltage gain is independent of a load impedance of a receiver. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when a transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0136] For example, the wireless charging system operates at an independent charge point (^0, X0). To be specific, the voltage gain between the receiver output voltage and the transmitter input voltage is X0, the transmitter input voltage is Vin0, the receiver output voltage is Vout0, Vout0/Vin0 = X0, and An operating frequency at which the transmitter transfers power to the receiver is ^0. When the transmitter output load jumps, as the wireless charging system operates at the independent point of load, an output load jump does not affect the voltage gain between the receiver output voltage and the transmitter input voltage, and the voltage gain is still X0. The transmitter input voltage Vin0 does not change, and therefore the receiver output voltage Vout0 does not change. The fluctuation of a voltage that is input into the voltage regulator module fluctuates very slightly before and after the output load jump. Therefore, the electrical power loss of the voltage regulator module is reduced, and the charging efficiency of the receiver can be improved.

[0137] To help understand the embodiments of this application, some concepts or terms relating to an independent point of load in the embodiments of this application are explained.

[0138] (1) Coupling factor and mutual inductance

[0139] A coupling factor is used to represent the closeness of coupling between the transmitter coil in the transmitter 10 and the receiver coil in the receiver 20. A higher coupling factor indicates higher efficiency at which the transmitter coil in the transmitter 10 transfers power to the receiver coil in the receiver 20. The coupling factor is related to the position deviation between the transmitter 10 and the receiver 20. A greater position deviation between the transmitter 10 and the receiver 20 indicates lower proximity of the coupling between the transmitter coil in the transmitter 10 and the receiver coil in the receiver 20 and the lowest coupling factor. Therefore, during wireless charging, a smaller position deviation between the transmitter 10 and the receiver 20 leads to a higher charging efficiency of the wireless charging system. That is, a coupling factor K is determined by the position deviation between the transmitter 10 and the receiver 20. The position deviation here is a deviation between the positions of the transmitter coil in the transmitter 10 and the receiver coil in the receiver 20. For details, refer to Figure 2. Figure 2 is a schematic diagram of a position offset between a transmitter and a receiver in accordance with an embodiment of this application. As shown in Figure 2, a position deviation s between the transmitter 10 and the receiver 20 can be understood as a deviation between the positions of a center of the transmitter coil 104 in the transmitter 10 and a center of the receiver coil 201 in the receiver 20 , for example, may be a horizontal distance between the center of the transmitter coil 104 in the transmitter 10 and the center of the receiver coil 201 in the receiver 20. If the transmitter 10 includes a plurality of transmitter coils, the position deviation between transmitter 10 and receiver 20 may alternatively be understood as an offset between positions of a center of a target transmitter coil in transmitter 10 and the center of receiver coil 201 in receiver 20. The target transmitter coil may be one or more transmitter coils in the transmitter 10 that are closest to the receiver coil 201 in the receiver 20.

[0140] A mutual inductance is an abbreviation for a mutual induction coefficient, and can be used to represent the magnitude of a mutual induction phenomenon between the transmitter coil in the transmitter and the receiver coil in the receiver. A relationship between the coupling factor K and the mutual inductance M is: , where Lp and Ls are respectively an equivalent inductance of the receiver and an equivalent inductance of the transmitter during power transfer. The magnitude of the mutual inductance can also reflect the positional deviation between the transmitter and receiver.

[0141] The coupling factor and mutual inductance can both be used to indicate a degree of coupling between the transmitter coil in transmitter 10 and the receiver coil in receiver 20. Of course, a newly defined parameter can also be used to indicate the degree of coupling between the transmitter coil in transmitter 10 and the receiver coil in receiver 20. The coupling factor K is used as an example for description in embodiments of this application. It can be understood that in embodiments of this application, the degree of coupling between the transmitter coil in the transmitter 10 and the receiver coil in the receiver 20 is not limited to being indicated by the coupling factor, but may be indicated by the mutual inductance or may be indicated by another newly defined parameter.

[0142] (2) Operating frequency and voltage gain

[0143] An operating frequency is a frequency at which the transmitter transfers power to the receiver in the wireless charging system. Different power is transferred over a coupling coil at different operating frequencies. When the operating frequency is , the power transferred over the coupling coil is maximum.

[0144] When the output power or an output voltage of the receiver needs to be regulated, the control information can be transmitted to the transmitter in the form of an error control information packet via in-band communication, the transmitter adjusts , based on control information, an operating frequency at which the transmitter transfers power, thereby adjusting the strength of a magnetic field at the equivalent inductance Lp of the transmitter to achieve an expected output power or an expected output voltage of the receiver .

[0145] A voltage gain is a ratio of an output voltage of a receiver to an input voltage of a transmitter. The output voltage is a voltage value that is obtained after rectification by an AC/DC conversion module in the receiver, and the input voltage is a voltage value that is obtained after conversion by a DC/AC conversion module in the transmitter . When an operating frequency of the wireless charging system changes, a voltage gain changes accordingly.

[0146] (3) Independent load point

[0147] a. What is an independent load point?

[0148] The load independent point is a point that lies on a relationship curve between a voltage gain and an operating frequency and at which a change in a receiver's output load impedance does not affect a voltage gain and an operating frequency of the wireless charging system.

[0149] Figure 3 shows an equivalent circuit model of a wireless charging system in accordance with an embodiment of this application. As shown in Figure 3, the wireless charging system shown in Figure 1 can be equivalent to a magnetic coupling structure model of the wireless charging system shown in Figure 3. An output voltage of a transmitter is Uop, a current transmitter output is Iop, and a frequency of an output voltage and output current is fop. Cp is a series matching capacitance of the transmitter, Lp is a self-inductance applied when a transmitter coil in the transmitter transfers power to the receiver, and Rp is an input resistance of the transmitter. Cs is a series matching capacitance of the receiver, Ls is a self-inductance applied when a receiver coil in the receiver receives the power transferred by the transmitter, Rs is a receiver resistance, is a current through the receiver coil, and ZL is a load impedance. iL and uL are a load current and a load voltage, respectively. K is a coupling factor between the transmitter coil and the receiver coil. A series matching capacitor (whose capacitance is Cp) of the transmitter and the transmitter coil form a first oscillation circuit, a series matching capacitor (whose capacitance is Cs) of the receiver and the receiver coil form a second oscillation circuit. oscillation, and the first oscillation circuit is configured to transfer power to the second oscillation circuit. The second oscillation circuit is configured to receive power transferred by the first oscillation circuit, and transfer the power to an AC/DC conversion module. In embodiments of this application, the transmitter's series matching capacitor may be referred to as a first series matching capacitor, and the receiver's series matching capacitor may be referred to as a second series matching capacitor.

[0150] When the coupling factor K is fixed, a curve of a relationship between a voltage gain X and an operating frequency & varies with a receiver output load impedance. Figure 4 is a schematic diagram of a relationship between a voltage gain and an operating frequency in accordance with an embodiment of this application. As shown in Figure 4, when the coupling factor K is a fixed value K0, a set of curves corresponding to a load impedance ZL whose values are Z1, Z2, and Z3 are respectively plotted, where Z1, Z2, and Z3 are different values. The set of curves that correspond to Z1, Z2, and Z3 intersect at the same point. At this intersection point, regardless of a value of the charging impedance of the wireless charging system, an operating frequency is , a voltage gain is X0, and ( , X0) can be referred to as a charge-independent point. The independent charging point is an inherent feature of the wireless charging system. At the independent charging point, if the operating frequency of the wireless charging system is regulated to , the voltage gain is invariably X0 regardless of a value of the receiver's output load impedance ZL.

[0151] The following provides a specific calculation of the voltage gain X0 and the operating frequency from the independent charging point of the wireless charging system.

[0152] Since the wireless charging system has a fixed voltage gain at the independent point of charge, and a transformer circuit has a constant voltage transformation ratio, if the voltage gain is analogous to the voltage transformation ratio, The wireless charging system that operates at the independent point of charge can be equivalent to a transformer circuit model. Figure 5 shows another equivalent circuit model of a wireless charging system in accordance with an embodiment of this application.

[0153] As shown in Figure 5, in the equivalent transformer circuit model, Lkp is a transformer primary leakage inductance, Lks is a transformer secondary leakage inductance, and Lm is a transformer primary excitation inductance. A transformer voltage transformation ratio can be understood as a voltage gain can be equivalent to the transformer equivalent transformer circuit model shown in Figure 5 only when the wireless charging system operates at an independent point of charge.

[0154] The following can be obtained based on the equivalent transformer circuit model:

[0155] In the equivalent transformer circuit model, it can be learned that Cp and Lkp form series resonance, and Cs and Lks form series resonance. A primary side and a secondary side have the same series resonance frequency , the series resonance frequency is an operating frequency of the wireless charging system, and the series resonance frequency is calculated as follows:

[0156] The following can be obtained based on formula (3):

[0157] The following can be obtained by classifying formula (4):

[0158] Usually, after the wireless charging system has been designed, Lp, Cp, Ls, and Cs are fixed values. Therefore, assuming that Lp *Cp -Ls *Cs = Const (briefly referred to as Const below), a voltage transformation ratio of the equivalent transformer circuit model can be obtained, that is, the voltage gain X of the charging system wireless is:

[0159] and X0 can be expressed as formula (3) and formula (6), respectively.

[0160] It can be learned that a load-independent point is related to a coupling factor. During true wireless charging, when the positions at which the transmitter and receiver are placed are defined, the coupling factor is a fixed value. Therefore, when the relative displacement of the transmitter and receiver is constant, the load-independent point is also defined. The relationship between the coupling factor K and the mutual inductance M is . Therefore, a relationship between the mutual inductance M and the load-independent point is similar to that between the coupling factor and the load-independent point.

[0161] b. Two independent charging points

[0162] Based on the above properties of the load independent point, a design idea of this application is described below.

[0163] It can be learned from formula (6) that the load independent point is related to Const in addition to the coupling factor. Figure 6 is a schematic diagram of another relationship between a voltage gain and an operating frequency in accordance with an embodiment of this application. As shown in Figure 6, when Const > 0, and coupling factor values K are K0, K1, and K2, respectively, corresponding independent load points are (ϖ0, X0), (ϖ1, X1), and (ϖ, X2), respectively. Position deviations, which correspond to the coupling factors K0, K1, and K2, between the transmitter and receiver are s0, s1, and s2, respectively, where s0 > s1 > s2. It can be learned with reference to Figure 5 and formula (6) that when Const > 0, a voltage gain increases and an operating frequency decreases at the load-independent point as the position deviation increases. When Const < 0, both voltage gain and operating frequency decrease at the load-independent point as the position deviation increases.

[0164] When Const = 0, the following is obtained by substituting Const = 0 into formula (6):

[0165] It can be learned from formula (7) that when Const = 0, the voltage gain at the load-independent point is invariably , and is no longer related to a degree of coupling of the two coils. Figure 7 is a schematic diagram of yet another relationship between a voltage gain and an operating frequency in accordance with an embodiment of this application. When values of coupling factor K are K0, K1, and K2, respectively, corresponding independent load points are (ϖ0, X0), (ϖ1, X0), and (ϖ2, X0), respectively, where . Position deviations, which correspond to the coupling factors K0, K1, and K2, between the transmitter and receiver are s0, s1, and s2, respectively, where s0 > s1 > s2. It can be learned that regardless of a position deviation between the transmitter and receiver, a voltage gain at the load-independent point is invariably . When Const = 0, a voltage gain remains unchanged and an operating frequency gradually decreases at the load-independent point as the position deviation increases. In other words, when Const = 0, the voltage gain at the load-independent point is not related to the position deviation between the two devices. As Const = Lp * Cp - Ls * Cs = 0, Cp/Cs = Ls/Lp, that is, the voltage gain at the load-independent point can also be expressed as .

[0166] Based on the above properties of Const = 0 and Const / 0, wireless charging methods in which a wireless charging system operates at an independent charging point are designed, respectively. Descriptions are separately given below.

[0167] When Const = 0, a process of adjusting a wireless charging system to operate at a load-independent point is as follows: Since the voltage gain at the load-independent point is not related to the position deviation between the two devices when Const = 0, the voltage gain is always . Based on the above property, the voltage gain of the wireless charging system can be regulated to the voltage gain at the independent point of load by regulating an operating frequency at which the transmitter transfers power to the receiver. Correspondingly, the operating frequency at which the transmitter transfers power to the receiver is ϖ0.

[0168] When Const / 0, a process of adjusting a wireless charging system to operate at a load-independent point is as follows: When Const / 0, a voltage gain operation ra change with a coupling factor. However, in formula (3) and formula (6), a primary excitation inductance Lm is related to a coupling factor, and Lm is unknown. Therefore, when Const/0, for the wireless charging system, the independent charge point cannot be directly obtained through calculation. A mapping relationship between a coupling factor, Const, and an independent load point can be pre-stored, to obtain a first mapping table. The wireless charging system may first determine the coupling factor between the transmitter and receiver based on a position deviation between the transmitter and receiver, and consult the first mapping table, to obtain an independent charge point that corresponds to the current coupling factor. Additionally, the wireless charging system is tuned to operate at this independent charging point.

[0169] c. How to adjust an independent load point?

[0170] In embodiments of this application, the wireless charging system needs to be adjusted to operate at the independent point of charge when transferring power. A voltage gain between a receiver output voltage and a transmitter input voltage can be set to invariably be a voltage gain X0 at the load-independent point, and an operating frequency at which the transmitter transfers power to the receiver is the operating frequency ϖ0 at the load-independent point. In a process of adjusting a gain for the voltage gain X0 at the load independent point, a voltage needs to be regulated. A voltage regulation module may be disposed in the transmitter, and is configured to regulate the input voltage of the transmitter to adjust the voltage gain to the voltage gain X0 at the load independent point. Alternatively, a voltage regulation module may be disposed in the receiver, and is configured to regulate the output voltage of the receiver to adjust the voltage gain to the voltage gain X0 at the load-independent point. The operating frequency is regulated to the operating frequency ra0 at the load-independent point through closed-loop frequency conversion.

[0171] In this embodiment of this application, the voltage regulation module may be disposed in the transmitter, or the voltage regulation module may be disposed in the receiver. When Const = 0, various embodiments of methods for regulating a wireless charging system to operate at an independent point of charge are provided in the embodiments of this application based on the above main inventive principle and the above two modes.

[0172] When Const = 0, Lp * Cp - Ls * Cs = 0 is required in the wireless charging system. Therefore, one embodiment of this application provides a wireless charging system. As shown in Figure 3, in the wireless charging system, circuit parameters Lp, Cp, Ls, and Cs of a transmitter and a receiver can allow the voltage gain at the independent charging point not to change with the coupling factor. During actual operation, a position deviation slightly affects Lp and Ls. During circuit design, Lp, Cp, Ls, and Cs can be designed to meet , where k is a positive number that meets 0.8 < k < 1.2, so as to ensure that the wireless charging system operates close to the independent charge point. It can be understood that in this embodiment of this request, the condition that k meets 0.8 < k < 1.2 is not limited. For example, it could also be 0.7 < k < 1.3. The range can be determined based on a design accuracy requirement of the wireless charging system. This is not limited in this application.

[0173] Specifically, for example, circuit design for the wireless charging system that includes the transmitter and receiver makes k = 1, that is, Lp, Cp, Ls, and Cs in the wireless charging system meet Lp * Cp - Ls * Cs = 0. For another example, circuit design for the wireless charging system that includes the transmitter and receiver makes k = 0.8, that is, Lp, Cp, Ls, and Cs in the charging system. wireless charging meet Lp * Cp - 0.8 * Ls * Cs = 0. It should be noted that the above examples are merely used to explain this embodiment of this application, and should not be considered as a limitation.

[0174] (1) Implementation of wireless charging when Const = 0 and the voltage regulation module is arranged in the transmitter

[0175] Figure 8 is a schematic architectural diagram of another wireless charging system in accordance with an embodiment of this application. A transmitter 10 may include a DC power source 101, a DC/AC conversion module 102, a series matching capacitor (whose capacitance is Cp) 103, the transmitter coil 104, and a control module 105. A receiver 20 may include a receiver coil 201, a series matching capacitor (whose capacitance is Cs) 202, an AC/DC conversion module 203, a voltage regulator module 204, an output load 205, a modulation module 206, and a control module 207. For detailed descriptions of the above modules, refer to the architecture of the wireless charging system described in Figure 1. Details are not described here again.

[0176] In the wireless charging system described in Figure 8, a voltage regulation module 106 is additionally disposed in the transmitter, and is configured to regulate an input voltage of the transmitter, to adjust a voltage gain to a voltage gain X0 at a load-independent point. Specifically, the voltage regulation module 106 is configured to receive a DC voltage that is output by the DC power source 101, and receive a control signal that is output by the control module 105, to regulate the DC voltage. and adjust the voltage gain to the voltage gain X0 at the load-independent point.

[0177] The voltage regulation module 106 may be a DC/DC output voltage regulation module or a voltage adapter circuit. The voltage regulation module 106 is a first voltage regulation module.

[0178] Receiver 20 further includes a battery management system (battery management system, BMS) 208. Receiver 20 is further configured to receive an expected output voltage V_out_target sent by the BMS. The expected output voltage has the following two purposes: First, the V_out_target is used by the receiver to regulate an output voltage to the expected output voltage. Second, the expected output voltage V_out_target is further used by the transmitter to determine the transmitter input voltage as a first input voltage Vin_set based on the expected output voltage and voltage gain X0 at the load-independent point, and regulate the input voltage to the first Vin_set input voltage using the voltage regulation module in the transmitter. Descriptions are separately given below.

[0179] First, the regulation of the output voltage by the receiver to the expected output voltage V_out_target of the BMS is actually a closed-loop feedback regulation process. A specific regulation process is as follows: As shown in Figure 8, the receiver uses V_out_target as a reference for the voltage regulator module 204, and adds a preset increment to obtain a preset value of Vrect. The preset increment can be obtained through a look-up table, and is used to ensure normal operation of a relative chip. The receiver obtains a current Vrect output voltage from a rectifier by detecting the potential of a point of R1 and R2, obtains an error voltage based on the preset value of Vrect and the detected current Vrect, and sends the error voltage to the transmitter through in-band communication. The transmitter can regulate Vrect by changing a power transfer CT operating frequency between the transmitter and receiver. The receiver can finally adjust Vrect to the preset value of Vrect repeatedly using the above error voltage feedback mode. The preset value of Vrect obtained based on the expected output voltage is referred to below as a first output voltage.

[0180] Second, expected output voltage V_out_target is used by the transmitter to determine the transmitter input voltage as a first input voltage Vin_set based on the expected output voltage and voltage gain X0 at the independent load point, which is specifically based on the schematic structural diagram of the wireless charging system described in Figure 8.

[0181] Based on the schematic structural diagram of the wireless charging system described in Figure 8, Figure 9 is a schematic flowchart of a wireless charging method in accordance with an embodiment of this application. In the embodiment described in Figure 9, a voltage gain X0 at an independent load point (OT0, X0) of the wireless charging system is a first voltage gain. Regardless of a value of a coupling factor, the voltage gain X0 at the load-independent point is the first voltage gain. The wireless charging method may include the following steps:

[0182] S101. A receiver sends information indicating a first output voltage to a transmitter. The first output voltage is an expected output voltage of the receiver.

[0183] S102. The transmitter adjusts an input voltage of the transmitter to a first input voltage based on the first output voltage and a first voltage gain.

[0184] S103. The transmitter transfers power to the receiver at the first voltage gain.

[0185] In reality, when the transmitter transfers power to the receiver at the first voltage gain, as the first voltage gain is the voltage gain at the load-independent point, an operating frequency at which the transmitter transfers power to the receiver is the first operating frequency, and the transmitter input voltage is the first input voltage.

[0186] The expected output voltage of the receiver is sent by a BMS to a control module 207. In reality, regulating the transmitter input voltage to the first input voltage is also a closed-loop feedback regulation process . A specific process is as follows: The transmitter input voltage is gradually regulated based on the first input voltage. A change in the transmitter input voltage can cause a receiver output voltage to deviate from the first output voltage. A deviation of the receiver's output voltage causes the receiver to begin closed-loop feedback loop regulation of the first output voltage again, to regulate the output voltage to the expected output voltage, causing the transmitter to regulate a frequency of power transfer operation. After the above closed-loop feedback regulation process, the transmitter input voltage is finally regulated to the first input voltage, the voltage gain is the voltage gain power transfer is exactly the operating frequency ra0 at the load-independent point.

[0187] It should be noted that, in this embodiment of this application, the input voltage of the transmitter is an output voltage of a voltage regulation module 106 in the transmitter. The receiver output voltage is an output voltage Vrect from the AC/DC conversion module 203 in the receiver. In this embodiment of this order, the voltage gain X0 at the load-independent point is the first voltage gain.

[0188] In this embodiment of this application, the voltage gain at the independent load point of the wireless charging system is constant. To ensure that the wireless charging system operates at the independent point of charge, a capacitance Cp of a series matching capacitor of the transmitter, a self-inductance Lp applied when the transmitter coil transfers power to the receiver, a capacitance Cs of a series matching of the receiver, and a self-inductance Ls applied when the receiver coil receives the power transferred by the transmitter need to be designed, so that the above parameters meet , where k is a positive number that meets 0.8 < k < 1.2.

[0189] However, in a real circuit, considering factors such as circuit losses, when the voltage gain at the load-independent point is adjusted, the voltage gain can be increased or decreased by a shift. The first voltage gain X0 can be a positive number that meets . For example, a voltage gain value at the load-independent point is set to or . It can be understood that in this embodiment of this application, a specified offset for the voltage gain is not limited. For example, alternatively, the first voltage gain can be adjusted to or . The range can be determined based on a design accuracy requirement of the wireless charging system. This is not limited in this application.

[0190] Regardless of the value of the coupling factor, the voltage gain at the load-independent point is invariably . The voltage gain is adjusted to be within a range of or within a range of , so that the wireless charging system operates close to the load-independent point, and the voltage gain is independent of a receiver's load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0191] The first output voltage may be the expected output voltage of the BMS at the receiver. During wireless charging, the expected output voltage of the BMS on the receiver may change. The expected output voltage of the BMS can be affected by factors such as the amount of electricity from the receiver. For example, the voltage gain at the load-independent point is 1.1. If the receiver has a relatively small amount of electricity (which may be lower than a threshold), the expected output voltage of the BMS at the receiver may be 9.9 V. The receiver returns a difference between a current output voltage a specified output voltage to the transmitter through a closed loop circuit. The transmitter regulates an operating frequency when receiving the voltage difference. An output voltage of the voltage regulator module in the receiver is regulated to 9.9 V through the above closed-loop regulation process. Additionally, the receiver sends the expected output voltage of 9.9 V from the BMS to the transmitter, and the transmitter determines by calculation based on the expected output voltage of 9.9 V from the BMS and the voltage gain of 1 ,1, that the transmitter input voltage is 9 V. Therefore, the transmitter gradually regulates the transmitter input voltage using the voltage regulation module, and a change in the transmitter input voltage causes the output voltage of the receiver deviates from 9.9 V. When the receiver detects that the receiver output voltage deviates from 9.9 V, the receiver starts the closed loop circuit to return the difference between the current output voltage and the output voltage specified for the transmitter, and the transmitter re-regulates the operating frequency based on the voltage difference. After the above closed-loop regulation is completed, the input voltage of the transmitter is 9 V, the output voltage of the receiver is 9.9 V, the voltage gain is 1.1, and the operating frequency is exactly the operating frequency at the load independent point.

[0192] After wireless charging continues for a period of time, if the receiver has a relatively large amount of electricity (which may be higher than another threshold), the expected output voltage of the BMS may be 5.5 V. The current output voltage of the receiver is still 9.9 V, and then the receiver can repeat the above closed-loop circuit regulation process. The transmitter input voltage is finally set to 5V, the receiver output voltage is set to 5.5V, the voltage gain is 1.1, and the operating frequency is exactly the operating frequency at the independent point of load.

[0193] When the wireless charging system performs power transfer at the independent point of charge, if the receiver moves, a position deviation between the receiver and the transmitter changes, and then a coupling factor between an inductor coil of the transmitter and a receiver inductor coil changes. As shown in Figure 7, if the coupling factor applied before the receiver moves is K0, the wireless charging system operates at the charge-independent point (ro0, X0). If the coupling factor applied after the receiver moves is K1, the independent load point of the wireless charging system becomes (ro1, X0). After the receiver moves, as shown in Figure 7, a ro-X 1 curve becomes a ro-X 2 curve. As the operating frequency is still ro0, a corresponding voltage gain increases, and the output voltage deviates from the expected output voltage of the BMS. The receiver can perform the closed-loop circuit regulation process. For a specific process, refer to the detailed descriptions in step S104. Details are not described here again. After the closed loop regulation is completed, the voltage gain is brought back to X0, the corresponding operating frequency is ro1, and the wireless charging system operates at the charge independent point (rol, to the coupling factor K1.

[0194] It should be understood that the examples are merely used to explain this embodiment of this application, and should not be considered as a limitation.

[0195] In this embodiment of this application, the first input voltage is obtained by dividing the first output voltage by the first voltage gain. The first voltage gain can be sent by the receiver to the transmitter. The receiver can obtain the first voltage gain through calculation based on Cp and Cs (or Ls and Lp) and send the first voltage gain to the transmitter. Alternatively, the receiver can preset a voltage gain and send the voltage gain to the transmitter. Alternatively, the first voltage gain can be obtained by the receiver through calculation based on Cp and Cs (or Ls and Lp), and the transmitter can receive in advance the information sent by the receiver and indicating Cs or the information sent by the receiver and which indicate Ls. Cs (Ls) and the first output voltage can be indicated by the same piece of information, or they can be indicated by different pieces of information. This is not limited in this application.

[0196] In the above description, the voltage regulation module is arranged in the transmitter, and the transmitter regulates the voltage gain to the voltage gain at the independent charging point by regulating the input voltage, so that the charging system without wire finally operates at the load-independent point. Alternatively, the voltage regulation module may be disposed in the receiver, which is described in detail below.

[0197] The wireless charging system operates close to the load independent point, so that the voltage gain is independent of a receiver load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved.

[0198] The voltage gain at the load-independent point is also not related to the coupling factor. In other words, during wireless charging, regardless of a position deviation between the transmitter and receiver, the voltage gain at the independent charging point is invariably . During a process of regulating the wireless charging system to operate at the independent charge point, it is only required to regulate the voltage gain between the receiver output voltage and the transmitter input voltage to be close to , and the operating frequency at which the wireless charging system performs power transfer can be regulated to the operating frequency at the independent charging point under an effect of a closed loop circuit, so that the wireless charging system can operate at independent point of load. It can be learned that regardless of the position deviation between the transmitter and receiver, it is only required to regulate the voltage gain between the receiver output voltage and the transmitter input voltage to be close to , and the convenience to regulate the wireless charging system to operate at the independent charging point can be improved.

[0199] (2) Implementation of wireless charging when Const = 0 and the voltage regulation module is arranged in the receiver

[0200] Figure 10 is a schematic structural diagram of yet another wireless charging system in accordance with an embodiment of this application. A transmitter 10 may include a DC power source 101, a DC/AC conversion module 102, a series matching capacitor (whose capacitance is Cp) 103, a transmitter coil 104, and a control module 105. A receiver 20 may include a receiver coil 201, a series matching capacitor (whose capacitance is Cs) 202, an AC/DC conversion module 203, a voltage regulator module 204, an output load 205, a modulation module 206, a control module 207, and a battery management system 208. For detailed descriptions of the above modules, refer to the wireless charging system architectures described in Figure 1 and Figure 8. Details are not described here again. The series matching capacitor 103 is a first series matching capacitor, and the series matching capacitor (whose capacitance is Cs) 202 is a second series matching capacitor.

[0201] In the wireless charging system described in Figure 10, a voltage regulation module 209 is additionally disposed in the receiver, and is configured to regulate an output voltage of the receiver, to adjust a voltage gain to a voltage gain. X0 at a load-independent point. Specifically, the voltage regulation module 209 is configured to receive a voltage that is output by the AC/DC conversion module 203, and receive a control signal that is output by the control module 207, to regulate the voltage and adjust the gain. of voltage for the voltage gain X0 at the load-independent point. The voltage regulation module 209 is a second voltage regulation module.

[0202] A process in which receiver regulates the output voltage of the receiver to the first output voltage is also a closed loop feedback regulation process. A specific process is as follows: The output voltage of the receiver is gradually regulated based on the first output voltage. The receiver obtains a voltage difference based on a calculation of the first output voltage and the current output voltage of the receiver's voltage regulation module, and sends the voltage difference to the transmitter via in-band communication. The transmitter regulates the operating frequency based on the voltage difference. After the above closed-loop feedback regulation process, when the regulation is completed, the output voltage of the receiver is finally regulated to the first output voltage, the voltage gain is the voltage gain X0 at the load independent point, and the power transfer operating frequency is exactly the operating frequency ra0 at the load-independent point.

[0203] Based on the schematic structural diagram of the wireless charging system described in Figure 10, Figure 11 is a schematic flowchart of another wireless charging method in accordance with an embodiment of this application. In this embodiment described in Figure 11, a voltage gain at a load-independent point (w0, X0) of the wireless charging system is a constant X0. Regardless of a value of a coupling factor, the voltage gain at the load-independent point is X0. The wireless charging method may include the following steps:

[0204] S201. A transmitter sends information indicating a first input voltage to a receiver. The first input voltage is a transmitter input voltage.

[0205] S202. The receiver adjusts an output voltage of the receiver to a first output voltage based on the first input voltage and a first voltage gain.

[0206] S203. The transmitter transfers power to the receiver at the first voltage gain.

[0207] In reality, when the transmitter transfers power to the receiver at the first voltage gain, as the first voltage gain is the voltage gain at the load-independent point, an operating frequency at which the transmitter transfers power to the receiver is a first operating frequency, and the output voltage of the receiver is the first output voltage.

[0208] When the receiver regulates the output voltage to the first output voltage and the voltage gain is , the transmitter regulates a power transfer operating frequency to the operating frequency at the independent point of load through closed loop feedback regulation. In this case, the wireless charging system operates at the independent charging point.

[0209] However, in a real circuit, considering factors such as circuit losses, when the voltage gain at the load-independent point is adjusted, the voltage gain can be increased or decreased by a shift. The first voltage gain X0 can be a positive number that meets For example, a voltage gain value at the load-independent point is set to or . It can be understood that in this embodiment of this application, a specified offset for the voltage gain is not limited. For example, alternatively, the first voltage gain can be adjusted to or . The range can be determined based on a design accuracy requirement of the wireless charging system. This is not limited in this application.

[0210] Before step S201, the transmitter may receive the information sent by the receiver and which indicates the first output voltage, and determine the transmitter input voltage as the first input voltage based on the first output voltage. The transmitter may determine the first input voltage based on a second pre-stored mapping table. The second mapping table includes at least one output voltage and one transmitter input voltage that correspond to each of the at least one output voltage. When the transmitter input voltage is the transmitter input voltage that corresponds to each output voltage, the wireless charging system is regulated to operate at the independent point of charge, and the receiver output voltage is each output voltage . In this case, the first output voltage meets the expected output voltage of the BMS in the receiver.

[0211] During a charging process of the wireless charging system, if the expected output voltage of the BMS at the receiver varies in different charging phases, the transmitter is also required to include a voltage regulation module. For the voltage regulation module, refer to the voltage regulation module 106 in the transmitter in the embodiment described in Figure 8. The voltage regulation module is configured to regulate the transmitter input voltage to the first input voltage after the transmitter determine the transmitter input voltage as the first input voltage based on the first output voltage.

[0212] When the wireless charging system performs power transfer at the independent point of charge, if the receiver moves, a position deviation between the receiver and the transmitter changes, and then the coupling factor between an inductor coil of the transmitter and a receiver inductor coil changes. As shown in Figure 7, if the coupling factor applied before the receiver moves is K0, the wireless charging system operates at the charge-independent point (ϖ, X0). If the coupling factor applied after the receiver moves is K1, the independent load point of the wireless charging system becomes (ϖ, X0). After the receiver moves, as shown in Figure 7, the ro-X curve 1 becomes the ro-X curve 2. As the operating frequency is still ro0, the corresponding voltage gain increases, and the output voltage deviates from the expected output voltage of the BMS. The receiver can perform the closed-loop circuit regulation process. For a specific process, refer to the detailed descriptions in step S104. Details are not described here again. After the closed loop regulation is completed, the voltage gain is brought back to X0, the corresponding operating frequency is ro1, and the wireless charging system operates at the charge independent point (ϖ, X0) that corresponds to the coupling factor K1.

[0213] In this embodiment of this application, the first output voltage is obtained by multiplying the first input voltage by the first voltage gain. The first voltage gain can be sent by the transmitter to the receiver. The transmitter can obtain the first voltage gain through calculation based on Cp and Cs (or Ls and Lp) and send the first voltage gain to the receiver. Alternatively, the first voltage gain can be obtained by the transmitter through a calculation based on Cp and Cs (or Ls and Lp). The receiver can receive in advance the information sent by the transmitter and indicating Cp or the information sent by the transmitter and indicating Lp. Cp (Lp) and the first input voltage can be indicated by the same piece of information, or they can be indicated by different pieces of information. This is not limited in this application.

[0214] The wireless charging system operates close to the point

[0215] The voltage gain at the load-independent point is also not related to the coupling factor. In other words, during wireless charging, regardless of a position deviation between the transmitter and receiver, the voltage gain at the independent charging point is invariably . During a process of regulating the wireless charging system to operate at the independent charge point, it is only required to regulate the voltage gain between the receiver output voltage and the transmitter input voltage to be close to , and the operating frequency at which the wireless charging system performs power transfer can be regulated to the operating frequency at the independent charging point under an effect of a closed loop circuit, so that the wireless charging system can operate at independent point of load. It can be learned that regardless of the position deviation between the transmitter and receiver, it is only required to regulate the voltage gain between the receiver output voltage and the transmitter input voltage to be close to , and the convenience to regulate the wireless charging system to operate at the independent charging point can be improved.

[0216] During wireless charging system design, a capacitance and an inductance may be designed based on a desired voltage gain. During charging, the voltage gain of the wireless charging system is adjusted to the voltage gain that corresponds to the independent charging point, that is, the first voltage gain. The wireless charging system operates at the independent point of charge. A change in a receiver's output resistance does not affect the power transfer operating frequency, and the change in the receiver's output resistance does not cause a change in voltage gain, either. Therefore, the receiver output voltage is constant, and an output voltage jump caused by a receiver output resistance jump is reduced, thereby reducing the electrical power consumed by the voltage regulator module and improving the efficiency of loading. Table 1 is an output voltage jump test result of a load jump at (w0, X0). Table 1 Test result of an output voltage jump caused by a load jump at (CT0, X0)

[0217] In Table 1, when the design values of Cp and Cs meet , that is, the wireless charging system operates at the independent point of charge, two jumps of a receiver current between 0.3 A and 1.25 A due to the output resistance jump in the receiver cause a corresponding fluctuation of 0. 65 V and 0.66 V at the receiver output voltage. When the design values of Cp and Cs do not meet , that is, the wireless charging system does not operate at the independent point of charge, two jumps of a receiver current between 0.3 A and 1.25 A due to the output resistance jump in the receiver cause a corresponding fluctuation of 4 .8 V and 3.6 V at the receiver output voltage. It can be learned that, the output voltage jump caused by the output resistance jump of the receiver can be reduced by adjusting the wireless charging system to operate at the independent point of charge, thereby reducing the electrical power consumed by the regulator module. voltage and improving charging efficiency.

[0218] In this embodiment of this application, in reality, when Const / 0, the wireless charging system can also be designed to operate at the independent point of charge. When the circuit parameters Lp, Cp, Ls, and Cs of the transmitter and receiver do not meet Const = 0, the voltage gain at the load-independent point is no longer invariably , and the voltage regulation module may be disposed in the transmitter, or the voltage regulation module may be disposed in the receiver. Various embodiments of methods for regulating a wireless charging system to operate at an independent point of charge are separately provided in the embodiments of this application based on the above two modes.

[0219] (1) Implementation of wireless charging when Const / 0 and voltage regulation module is arranged in the transmitter

[0220] Based on the schematic structural diagram of the wireless charging system described in Figure 8, Figure 12 is a schematic flowchart of yet another wireless charging method in accordance with an embodiment of this application. In this embodiment described in Figure 12, a voltage gain X0 at an independent load point (ro0, X0) of the wireless charging system is related to a coupling factor. The wireless charging method may include the following steps:

[0221] S301. A receiver finds, from a first mapping table, a first charge-independent point that corresponds to a first degree of coupling, where the first charge-independent point includes a first voltage gain.

[0222] S302. The receiver sends information indicating the first independent point of charge to a transmitter.

[0223] S303. The receiver sends information indicating a first output voltage to the transmitter.

[0224] S304. The transmitter adjusts a transmitter input voltage to a first input voltage based on the first output voltage and a first voltage gain.

[0225] S305. The transmitter transfers power to the receiver at the first voltage gain.

[0226] In reality, when the transmitter transfers power to the receiver at the first voltage gain, as the first voltage gain is the voltage gain at the load-independent point, an operating frequency at which the transmitter transfers power to the receiver is the first operating frequency, and the transmitter input voltage is the first input voltage.

[0227] In this embodiment of this application, the receiver may pre-store the first mapping table, the first mapping table may include at least one degree of coupling and an independent load point corresponding to each of the at least one degree of coupling. coupling, and the load-independent point is a combination of a voltage gain and an operating frequency. At an operating frequency at a load-independent point corresponding to each degree of coupling, a voltage gain at the load-independent point corresponding to the degree of coupling is independent of a receiver output load. The above degree of coupling can be a coupling factor or a mutual inductance. The coupling factor is described below as an example.

[0228] The first mapping table can have two forms depending on whether Const is known. Descriptions are separately given below.

[0229] (a) Const is known.

[0230] If Cp and Lp of the transmitter are known to the receiver, or Cs and Ls of the receiver are known to the transmitter, Lp * Cp -Ls *Cs = Const is known. For the known Const, different coupling factors can be preset to measure an independent point of load. For example, a position offset is changed in fixed steps to test or calculate a corresponding coupling factor and a load-independent point that corresponds to the coupling factor. For details, refer to Table 2. Table 2 is a schematic diagram of a first mapping table in accordance with an embodiment of this application. Table 2 Example of a first mapping table (Const = Const 0)

[0231] As shown in Table 2, Const that corresponds to the transmitter and receiver is Const 0. In this case, a coupling factor Ku that corresponds when the position deviation s is su (u = 0, 1, 2, .. ., n), and a charge-independent point (Xu, rau) can be tested and stored in advance, where n and u are both natural numbers.

[0232] The receiver may pre-store the above first mapping table. When the transmitter transfers power to the receiver, the receiver finds a corresponding charge-independent point based on a detected position deviation between the receiver and transmitter, and then sends the found charge-independent point to the receiver. For example, if the receiver detects that a current position offset between the receiver and transmitter is s2, the receiver determines, through a lookup table based on the first pre-stored mapping table above, that a coupling factor is K2 and an independent point of charge is (X2, ra2).

[0233] Additionally, when the voltage gain and input voltage of the transmitter are regulated, the operating frequency ra is regulated using a closed loop circuit. This is passive regulation, and there is no need to know a specific value of the operating frequency ra. To reduce the amount of stored data and save storage space, the receiver can alternatively pre-store only the voltage gain X at the load-independent point in the first mapping table. For details, refer to Table 3. Table 3 is a schematic diagram of another first mapping table in accordance with an embodiment of this application. Table 3 Example of a first mapping table (Const = Const 0)

[0234] As shown in Table 3, Const that corresponds to the transmitter and receiver is Const 0. A coupling factor Ku that corresponds when the position deviation s is su (u = 0, 1.2, ..., n ), and a voltage gain Xu at a load-independent point is tested and stored in advance, where n and u are both natural numbers.

[0235] The receiver may pre-store the above first mapping table. When the transmitter transfers power to the receiver, the receiver finds a corresponding voltage gain at a load-independent point based on a detected position deviation between the receiver and transmitter, and then outputs the voltage gain found at the independent point. load for the transmitter. For example, if the receiver detects that a current position offset between the receiver and transmitter is s2, the receiver determines, through a lookup table based on the first pre-stored mapping table above, that a coupling factor is K2 and a voltage gain at a point independent of load is X2.

[0236] After the receiver finds the voltage gain at the load-independent point, the receiver or transmitter can alternatively calculate the operating frequency at the load-independent point based on formula (3) and formula (6).

[0237] (b) Const is unknown.

[0238] If the transmitter by which the receiver is carried is unknown, or the receiver carried by the transmitter is unknown, that is, Cp and Lp of the transmitter are unknown to the receiver, or Cs and Ls of the receiver are unknown to the transmitter, a Const value can be changed in fixed steps to test different coupling factors under different Const and independent load points that correspond to the coupling factors. Independent load points corresponding to different Const and K coupling factors can be pre-stored. For details, refer to Table 4. Table 4 is an example of yet another first mapping table in accordance with an embodiment of this application. Table 4 Example of a first mapping table (Const is unknown)

[0239] As shown in Table 4, a load-independent point (Xvu, ravu) that corresponds when the position deviation s is su (u = 0, 1, 2, ..., n), and Const is Const v (v = 0, 1, 2, ..., m) is tested and stored in advance, where m, n, u, and v are all natural numbers.

[0240] The receiver may pre-store the above first mapping table. When the transmitter transfers power to the receiver, the receiver can first obtain Lp and Cp from the transmitter, and obtain Const through calculation. The receiver finds a corresponding load-independent point based on Const obtained through calculation and a detected position deviation between the receiver and transmitter, and then sends the found load-independent point to the transmitter. For example, if Const obtained by the receiver through calculation is Const 1, and the receiver detects that a current position deviation between the receiver and transmitter is s2, the receiver determines through a lookup table based on the first lookup table pre-stored mapping above, that the load independent point is (X12, rn12).

[0241] Of course, to save storage space, the receiver may alternatively pre-store only the voltage gain X at the load-independent point in the first mapping table. For details, refer to Table 5. Table 5 is a schematic diagram of yet another first mapping table in accordance with an embodiment of this application. Table 5 Example of a first mapping table (Const is unknown)

[0242] As shown in Table 5, a voltage gain (v = 0, 1,2, ..., m) is tested and stored in advance, where m, n, u, and v are all natural numbers.

[0243] The receiver may pre-store the above first mapping table. When the transmitter transfers power to the receiver, the receiver can first obtain Lp and Cp from the transmitter, and obtain Const through calculation. The receiver finds a corresponding voltage gain at a load-independent point based on Const obtained through calculation and a detected position deviation between the receiver and transmitter, and then sends the voltage gain found at the load-independent point to the transmitter. For example, if Const obtained by the receiver through calculation is Const 1, and the receiver detects that a current position deviation between the receiver and transmitter is s2, the receiver determines through a lookup table based on the first lookup table pre-stored mapping above, that the voltage gain at the independent load point is X12.

[0244] As the receiver is usually a mobile terminal and has very high data storage and processing capabilities, if the first mapping table is stored in the receiver, the burden on the transmitter for data processing and storage can be reduced, a lookup table speed can be accelerated, and a delay to regulate a load independent point can be reduced. Of course, the first mapping table above can alternatively be stored in the transmitter. The transmitter can directly obtain the load-independent point through a look-up table, and the load-independent point does not need to be sent using receiver. Bandwidth communication can be reduced, and signaling overruns can be reduced.

[0245] When Const / 0 and the expected output voltage of the BMS at the receiver change neither the voltage gain nor the operating frequency at the independent load point changes. The receiver or transmitter does not need to consult the first mapping table again, and only needs to repeat steps S303 to S305, to re-adjust the wireless charging system to operate at the independent charging point based on the first changed output voltage. and in the load-independent point voltage gain.

[0246] When Const/0 and the wireless charging system operates at the independent charging point, if the position deviation between the transmitter and receiver changes, for example, a charging position of the transmitter changes, the coupling factor changes , and the voltage gain and operating frequency at the independent charging point of the wireless charging system also change. The charge-independent point needs to be determined again, and the wireless charging system is regulated to operate at the charge-independent point, that is, steps S301 to S305 are repeated based on a new coupling factor obtained after deflection of position changes.

[0247] However, in a real circuit, considering factors such as circuit losses, after the voltage gain X0 at the load-independent point corresponding to the coupling factor is found, when the voltage gain is adjusted, the voltage gain Voltage can be adjusted to the voltage gain X0 at the load-independent point plus or minus an offset. For example, the voltage gain is set to the first voltage gain X0, and the first voltage gain X0 can be a positive number that meets . For example, a voltage gain value at the load-independent point is set to (1+20%) or (1-20%). It can be understood that in this embodiment of this application, a specified offset for the voltage gain is not limited. For example, alternatively, the first voltage gain can be adjusted to (1+30%) or (1-30%). The range can be determined based on a design accuracy requirement of the wireless charging system. This is not limited in this application.

[0248] The load independent point is found from the first mapping table using the degree of coupling. The wireless charging system can be adjusted to operate at a load-independent point by adjusting a voltage gain to a voltage gain at the load-independent point, such that the voltage gain is independent of a receiver load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved. Circuit parameters of the transmitter and receiver do not need to be limited, and the generality of the transmitter and receiver is improved.

[0249] It can be learned that the first voltage gain at the load-independent point is determined in the above mode by consulting the first mapping table, and the circuit parameters in the transmitter and receiver do not necessarily need to meet , where k is a positive number that meets 0.8 < k < 1.2. In this mode, the wireless charging system can be adjusted to the independent charging point. In other words, the transmitter or receiver that has any circuit parameter can operate at the load-independent point. Therefore, the generality of the transmitter and receiver can be improved.

[0250] In the above description, the voltage regulation module is arranged in the transmitter, and the transmitter regulates the voltage gain to the voltage gain at the independent charging point by regulating the input voltage, so that the charging system without wire finally operates at the load-independent point. Alternatively, the voltage regulation module may be disposed in the receiver, which is described in detail below.

[0251] (2) Implementation of wireless charging when Const / 0 and voltage regulation module is arranged in the transmitter

[0252] Based on the schematic structural diagram of the wireless charging system described in Figure 9, Figure 13 is a schematic flowchart of yet another wireless charging method in accordance with an embodiment of this application. In this embodiment described in Figure 13, a voltage gain X0 at an independent load point (ro0, X0) of the wireless charging system is related to a coupling factor. The wireless charging method may include the following steps:

[0253] S401. A receiver finds, from a first mapping table, a first charge-independent point that corresponds to a first degree of coupling, where the first charge-independent point includes a first voltage gain.

[0254] S402. The receiver receives information sent by a transmitter that indicates a first input voltage.

[0255] S403. The receiver adjusts an output voltage of the receiver to a first output voltage based on the first input voltage and a first voltage gain.

[0256] S404. The transmitter transfers power to the receiver at the first voltage gain.

[0257] In this embodiment of this application, the receiver may pre-store the first mapping table, the first mapping table may include at least one degree of coupling and an independent load point corresponding to each of the at least one degree of coupling. coupling, and the load-independent point is a combination of a voltage gain and an operating frequency. At an operating frequency at a load-independent point corresponding to each degree of coupling, a voltage gain at the load-independent point corresponding to the degree of coupling is independent of a receiver output load. The above degree of coupling can be a coupling factor or a mutual inductance. Mutual inductance is used as an example below.

[0258] For a description of the first mapping table, refer to the embodiment described in Figure 12. Details are not described here again.

[0259] An execution sequence of step S401 and step S402 is not limited. Before S401, the transmitter can receive the information sent by the receiver that indicates the first output voltage, and determine the transmitter input voltage as the first input voltage based on the first output voltage. The transmitter may determine the first input voltage based on a second pre-stored mapping table. The second mapping table includes at least one output voltage and one transmitter input voltage that correspond to each of the at least one output voltage. When the transmitter input voltage is a transmitter input voltage that corresponds to each output voltage, the wireless charging system is regulated to operate at the independent point of charge, and the receiver output voltage is each output voltage . In this case, the first output voltage meets the expected output voltage of the BMS in the receiver.

[0260] During a charging process of the wireless charging system, if the expected output voltage of the BMS at the receiver varies in different charging phases, the transmitter is also required to include a voltage regulation module. For the voltage regulation module, refer to the voltage regulation module 106 in the transmitter in the embodiment described in Figure 8. The voltage regulation module is configured to regulate the transmitter input voltage to the first input voltage after the transmitter determine the transmitter input voltage as the first input voltage based on the first output voltage.

[0261] When the wireless charging system performs power transfer at the load-independent point, if the receiver moves, the coupling factor changes, and the voltage gain and operating frequency at the load-independent point of the charging system wireless also changes. The charge-independent point needs to be determined again, and the wireless charging system is set to operate at the charge-independent point, that is, steps S401 to S404 are repeated.

[0262] The load independent point is found from the first mapping table using the degree of coupling. The wireless charging system can be adjusted to operate at a load-independent point by adjusting a voltage gain to a voltage gain at the load-independent point, such that the voltage gain is independent of a receiver load impedance. Therefore, regardless of the value of a receiver's output load impedance, both an operating frequency and a voltage gain that are used when the transmitter transfers power to the receiver are fixed values. In other words, the receiver output load impedance does not affect a voltage gain between a receiver output voltage and a transmitter input voltage. Therefore, the output voltage of the receiver is constant, an output voltage jump caused by a load jump can be reduced, an electrical power loss of a voltage regulator module can be reduced, and the charging efficiency of the receiver can be improved. Circuit parameters of the transmitter and receiver do not need to be limited, and the generality of the transmitter and receiver is improved.

[0263] During charging of the wireless charging system, the wireless charging system is set at the independent charging point. At the load-independent point, a change in a receiver output resistance does not affect the power transfer operating frequency, and the change in receiver output resistance does not cause a change in voltage gain either. Therefore, the receiver output voltage is constant, and an output voltage jump caused by a receiver output resistance jump is reduced, thereby reducing the electrical power consumed by the voltage regulator module and improving conversion efficiency. of electrical energy.

[0264] Figure 14 shows an electrical energy conversion efficiency test result in accordance with an embodiment of this application. An electrical power conversion efficiency test curve shown in Figure 14 is a test result produced when a center of a transmitter coil in a transmitter directly faces a center of a receiver coil in a receiver, that is, when the position deviation is 0. Electrical energy conversion efficiency can be understood as a ratio of electrical energy that is emitted by the transmitter and the electrical energy in the receiver that is used to supply power to a load. As shown in Figure 14, for any load current, the electrical energy conversion efficiency generated when a wireless charging system operates at an independent point of load is greater than the electrical energy conversion efficiency generated when the wireless charging system Wireless charging bypasses the independent point of charge. Therefore, when there is no position deviation between the transmitter and receiver, the wireless charging system is adjusted to operate at the independent charging point, and the electrical energy conversion efficiency of the wireless charging system can be improved.

[0265] Figure 15 shows another electrical energy conversion efficiency test result in accordance with an embodiment of this application. An electrical power conversion efficiency test curve shown in Figure 15 is a test result produced when a center of a transmitter coil in a transmitter deviates horizontally from a center of a receiver coil in a receiver by 10 mm, i.e. is, when the position deviation is 10 mm. As shown in Figure 15, for any load current, the electrical energy conversion efficiency generated when a wireless charging system operates at an independent point of load is greater than the electrical energy conversion efficiency generated when the wireless charging system Wireless charging bypasses the independent point of charge. Therefore, when there is a position deviation between the transmitter and receiver, the wireless charging system is adjusted to operate at the independent charging point, and the electrical energy conversion efficiency of the wireless charging system can be improved.

[0266] When the wireless charging system operates at the independent point of load, as the voltage gain does not change with a change in receiver load, in this case, the wireless charging system is equivalent to a transformer. Therefore, one phase of an output voltage from a DC/AC conversion module in the transmitter is the same as one phase of an input voltage from an AC/DC conversion module in the receiver. Furthermore, the phase of an input voltage of the AC/DC conversion module in the receiver is also the same as a phase of an input current of the AC/DC conversion module in the receiver. If the AC/DC conversion module in the receiver is implemented using a rectifier diode circuit, when the phase of an input voltage of the AC/DC conversion module is the same as the phase of the input current of the AC/DC conversion module DC, the diode has a zero current turn-off property. The zero current turn-off property of the diode can reduce electromagnetic interference and optimize rectifier efficiency.

[0267] Figure 16 is a schematic diagram of a test of a voltage and a current in accordance with an embodiment of this application. As shown in Figure 16, an output voltage of a DC/AC conversion module in a transmitter is V1, an output current of the DC/AC conversion module in the transmitter is I1, an input voltage of an AC conversion module /DC in a receiver is V2, and an input current of the AC/DC conversion module in the receiver is I2, where the phases of V1 and V2 are the same, and the phases of V2 and I2 are the same. The AC/DC conversion module in the receiver uses a diode circuit for rectification, where the diode has a zero current turn-off property. The zero current turn-off property of the diode can reduce electromagnetic interference and optimize rectifier efficiency.

[0268] The above describes in detail the method in the embodiments of this application, and the following provides the transmitter and receiver in the embodiments of this application.

[0269] Based on the system architecture in Figure 1, Figure 17 is a schematic structural diagram of a wireless charging system 100 in accordance with an embodiment of this application. The wireless charging system 100 includes a transmitter 10 and a receiver 20.

[0270] As shown in Figure 17, the transmitter 10 includes a transmitter coil 104 and a first series matching capacitor 103, and the transmitter coil 104 is connected to the first series matching capacitor 103 in series to form a first oscillation circuit 107; the first oscillation circuit 107 is configured to transfer power to the receiver 20; and a self-inductance applied when the transmitter coil 104 transfers power to the receiver 20 is Lp, and a capacitance of the first series matching capacitor 103 is Cp, where Lp * Cp =k * Ls * Cs; Ls is a self-inductance applied when a receiver coil 201 in the receiver 20 receives the power transferred by the first oscillation circuit, Cs is a capacitance of a second series matching capacitor 202 in the receiver 20, and k is a positive number that meets 0, 8 < k < 1.2; the receiver coil 201 is connected to the second series matching capacitor 202 in series to form a second oscillation circuit; the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and transmitter 10 further includes:

[0271] a control unit 108, configured to adjust a voltage gain between a receiver output voltage 20 and a transmitter input voltage 10 for the first voltage gain, where

[0272] the first voltage gain is X, and X is a positive number that meets or X is a positive number that meets when the voltage gain between the receiver output voltage and the transmitter input voltage is the first voltage gain, the wireless charging system operates at an independent charge point; the independent load point includes a first operating frequency and a first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; It is

[0273] the control unit 108 is further configured to control the first oscillation circuit 107 to transfer power to the receiver 20 at the first voltage gain.

[0274] As a possible implementation, k is 1, and X is or

[0275] As a possible implementation, the transmitter 10 further includes a receiving unit 109, and that a control unit 108 adjusts a voltage gain between an output voltage of the receiver 20 and an input voltage of the transmitter 10 for a first voltage gain includes:

[0276] the receiving unit 109 is configured to receive information sent by the receiver 20 and which indicates a first output voltage, where the first output voltage is an expected output voltage of the receiver; It is

[0277] the control unit 108 is further configured to adjust the input voltage of the transmitter 10 to a first input voltage based on the first output voltage and the first voltage gain.

[0278] As a possible implementation, the transmitter 10 may include a voltage regulation module 106. That control unit 108 adjusts the input voltage of the transmitter 10 to a first input voltage based on the first output voltage and the first voltage gain includes: the control unit 108 controls, based on the first output voltage and the first voltage gain, the voltage regulation module 106 to adjust the input voltage of the transmitter 10 to the first input voltage.

[0279] As a possible implementation, before the control unit 108 adjusts the voltage gain between the output voltage of the receiver 20 and the input voltage of the transmitter 10 for the first voltage gain, the receiving unit 109 is further configured to receive information sent by receiver 20 and indicating Cs and/or information sent by receiver 20 and indicating Ls, where Cs and Ls are used by transmitter 10 to determine the first voltage gain; and/or the receiving unit 109 is configured to receive the information sent by the receiver 20 and which indicates the first voltage gain.

[0280] As shown in Figure 17, the receiver 20 includes the receiver coil 201 and the second series matching capacitor 202, the receiver coil 201 is connected to the second series matching capacitor 202 in series to form a second circuit oscillation circuit 210, and the second oscillation circuit 210 is configured to receive the power transferred by the transmitter 10; a self-inductance applied when the receiver coil 201 receives the power transferred by the transmitter 10 is Ls, and a capacitance of the second series matching capacitor 202 is Cs, where Lp is a self-inductance applied when the transmitter coil 104 in the transmitter 10 transfers power to the receiver 20, Cp is a capacitance of the first series matching capacitor 103 in the transmitter 10, and k is a positive number that meets 0.8 < k <1.2; the transmitter coil 104 is connected to the first series matching capacitor 103 in series to form the first oscillation circuit 107; and the first oscillation circuit 107 is configured to transfer power to the second oscillation circuit 210.

[0281] The receiver 20 further includes a sending unit 212 and a control unit 211, where

[0282] the sending unit 212 is configured to send, to the transmitter 10, information indicating the first output voltage, where the first output voltage is the expected output voltage of the receiver 20, and the first output voltage is used by the transmitter 10 to adjust the input voltage of the transmitter 10 to the first input voltage based on the first output voltage and the first voltage gain, where

[0283] the first voltage gain is X, and X is a positive number that meets or X is a positive number that meets when the voltage gain between the output voltage of the receiver 20 and the input voltage of the transmitter 10 is the first voltage gain, the wireless charging system 100 operates at an independent point of charge; the independent load point includes a first operating frequency and a first voltage gain; and at the first operating frequency, the first voltage gain is independent of an output load of the receiver 20; It is

[0284] the control unit 211 is configured to control the second oscillation circuit 210 to receive the power transferred by the transmitter 10 at the first voltage gain.

[0285] In this embodiment of this application, the transmitter 10 may further include a DC power source 101 and a DC/AC conversion module 102. The receiver 20 may include an AC/DC conversion module 203, a voltage regulator module 204, an output charge 205, a modulation module 206, and a battery management system 208. For detailed descriptions of the above modules, refer to the wireless charging system architectures described in Figure 1 and Figure 8. Details are not available. described here again.

[0286] In this embodiment of this application, the control unit 108 can be implemented by the control module 105 in the embodiment described in Figure 8. The control unit 211 can be implemented by the control module 207 in the embodiment described in Figure 8. The unit control unit 108 may also have another function of the control module 105. For details, refer to the embodiment described in Figure 8. The control unit 211 may also have another function of the control module 207. For details, refer to the embodiment described in Figure 8. The functions of the control unit 108, the receiving unit 109, the control unit 211, and the sending unit 212 may correspond to the corresponding descriptions of the wireless charging method embodiment shown in Figure 9. Details are not herein described again.

[0287] Based on the wireless charging system 100 described in Figure 17, in another possible embodiment, the control unit 108 is configured to find, from a first mapping table, a first independent charging point that corresponds to a first degree of coupling; or

[0288] the receiving unit is configured to receive information sent by the receiver and which indicates a first charge-independent point, where the first charge-independent point is a first charge-independent point that corresponds to a first degree of coupling and found by the receiver of a first mapping table, where

[0289] the first independent point of load includes a first voltage gain, and the first degree of coupling is a degree of coupling between the coil in the transmitter and the coil in the receiver; the first mapping table includes at least one degree of coupling and a load-independent point that corresponds to each of the at least one degree of coupling, and the load-independent point is a combination of a voltage gain and an operating frequency ; and at an operating frequency at a load-independent point corresponding to each degree of coupling, a voltage gain at the load-independent point corresponding to the degree of coupling is independent of an output load of the receiver;

[0290] the control unit 108 is configured to adjust a voltage gain between a receiver output voltage 20 and a transmitter input voltage 10 for the first voltage gain; It is

[0291] the control unit 108 is further configured to control the first oscillation circuit 107 to transfer power to the receiver at the first voltage gain.

[0292] As a possible implementation, a control unit 108 adjusts a voltage gain between a receiver output voltage 20 and a transmitter input voltage 10 for the first voltage gain includes:

[0293] the receiving unit 109 is configured to receive information sent by the receiver 20 and which indicates a first output voltage, where the first output voltage is an expected output voltage of the receiver; and the transmitter 10 adjusts the input voltage of the transmitter to a first input voltage based on the first output voltage and the first voltage gain.

[0294] As a possible implementation, before the control unit 108 adjusts the voltage gain between the output voltage of the receiver 20 and the input voltage of the transmitter 10 for the first voltage gain, the receiving unit 109 is further configured to receive information sent by receiver 20 and indicating Cs and/or information sent by receiver 20 and indicating Ls, where Cs and Ls are used by transmitter 10 to determine the first voltage gain; and/or the transmitter 10 is configured to receive the information sent by the receiver 20 and which indicates the first voltage gain.

[0295] At the receiver 20, the sending unit 212 is configured to send, to the transmitter 10, information indicating a first output voltage, where the first output voltage is an expected output voltage of the receiver 20; and the first output voltage is used by the transmitter 10 to adjust an input voltage of the transmitter 10 to a first input voltage based on the first output voltage and the first voltage gain. The first voltage gain is included in a first load-independent point corresponding to a first degree of coupling and found by transmitter 10 of a first mapping table; or the first voltage gain is included in a first load-independent point corresponding to a first degree of coupling and found by the receiver 20 of a first mapping table; and the first charge-independent point is added to the information indicating the first charge-independent point, and then sent by the receiver 20 to the transmitter 10.

[0296] The first degree of coupling is a degree of coupling between the transmitter coil 104 in the transmitter 10 and the receiver coil 201 in the receiver 20; the first mapping table includes at least one degree of coupling and a load-independent point that corresponds to each of the at least one degree of coupling, and the load-independent point is a combination of a voltage gain and an operating frequency ; and at an operating frequency at a load-independent point corresponding to each degree of coupling, a voltage gain at the load-independent point corresponding to the degree of coupling is independent of a receiver output load.

[0297] The control unit 211 is configured to control the second oscillation circuit to receive the power transferred by the transmitter 10 at the first voltage gain.

[0298] In this embodiment of this application, the control unit 108 may be implemented by the control module 105 in the embodiment described in Figure 8. The control unit 211 may be implemented by the control module 207 in the embodiment described in Figure 8. Alternatively, the control unit 108 may be a controller 30 in the embodiment described in Figure 19. Alternatively, the control unit 211 may be a controller 40 in the embodiment described in Figure 19. The control unit 108 may have yet another control module function 105. For details, refer to the embodiment described in Figure 8. The control unit 211 may also have another function of the control module 207. For details, refer to the embodiment described in Figure 8. The functions of the control unit 108, of the unit The receiving unit 109, the control unit 211, and the sending unit 212 may correspond to the corresponding descriptions of the wireless charging method embodiment shown in Figure 12. Details are not described here again.

[0299] Based on the system architecture in Figure 1, Figure 18 is a schematic structural diagram of another wireless charging system 100 in accordance with an embodiment of this application. The wireless charging system 100 includes a transmitter 10 and a receiver 20.

[0300] As shown in Figure 18, the transmitter 10 includes a transmitter coil 104 and a first series matching capacitor 103, and the transmitter coil 104 is connected to the first series matching capacitor 103 in series to form a first oscillation circuit 107; the first oscillation circuit 107 is configured to transfer power to the receiver 20; and a self-inductance applied when the transmitter coil 104 transfers power to the receiver 20 is Lp, and a capacitance of the first series matching capacitor 103 is Cp, where Lp *Cp =k *Ls *Cs; Ls is a self-inductance applied when a receiver coil 201 in the receiver 20 receives the power transferred by the first oscillation circuit, Cs is a capacitance of a second series matching capacitor 202 in the receiver 20, and k is a positive number that meets 0, 8 < k < 1.2; the receiver coil 201 is connected to the second series matching capacitor 202 in series to form a second oscillation circuit; the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and transmitter 10 further includes:

[0301] the sending unit 108, configured to send, to the receiver 20, information indicating a first input voltage, where the first input voltage is an input voltage of the transmitter 10; and the first input voltage is used by the receiver to adjust an output voltage of the receiver to a first output voltage based on the first input voltage and a first voltage gain, where

[0302] the first voltage gain is X, and X is a positive number that meets , or X is a positive number that meets ; when the voltage gain between the output voltage of the receiver 20 and the input voltage of the transmitter 10 is the first voltage gain, the wireless charging system 100 operates at an independent point of charge; the independent load point includes a first operating frequency and a first voltage gain; and at the first operating frequency, the first voltage gain is independent of an output load of the receiver 20; It is

[0303] control unit 109 is configured to control the first oscillation circuit 107 to transfer power to the receiver 20 at the first voltage gain.

[0304] As shown in Figure 18, the receiver 20 includes the receiver coil 201 and the second series matching capacitor 202, the receiver coil 201 is connected to the second series matching capacitor 202 in series to form a second circuit oscillation circuit 210, and the second oscillation circuit 210 is configured to receive the power transferred by the transmitter 10; a self-inductance applied when the receiver coil 201 receives the power transferred by the transmitter 10 is Ls, and a capacitance of the second series L*C matching capacitor 202 is Cs, where Lp is a self-inductance applied when the transmitter coil 104 in the transmitter 10 transfers power to the receiver 20, Cp is a capacitance of the first series matching capacitor 103 in the transmitter 10, and k is a positive number that meets 0.8 < k <1.2; the transmitter coil 104 is connected to the first series matching capacitor 103 in series to form the first oscillation circuit 107; and the first oscillation circuit 107 is configured to transfer power to the second oscillation circuit 210.

[0305] The receiver 20 further includes a control unit 211, where

[0306] the control unit 211 is configured to adjust a voltage gain between a receiver output voltage 20 and a transmitter input voltage 10 for the first voltage gain, where

[0307] the first voltage gain is X, and X is a positive number that meets , or X is a positive number that meets when the voltage gain between the output voltage of the receiver 20 and the input voltage of the transmitter 10 is the first voltage gain, the wireless charging system 100 operates at an independent point of charge; the independent load point includes a first operating frequency and a first voltage gain; and at the first operating frequency, the first voltage gain is independent of an output load of the receiver 20; It is

[0308] the control unit 211 is further configured to control the second oscillation circuit 210 to receive the power transferred by the transmitter 10 at the first voltage gain.

[0309] As a possible implementation, k is 1, and X is or

[0310] As a possible implementation, the receiver 20 further includes a receiving unit 212, and the control unit 211 adjusts a voltage gain between an output voltage of the receiver 20 and an input voltage of the transmitter 10 for the first voltage gain includes:

[0311] the receiving unit 212 is configured to receive information sent by the transmitter 10 and which indicates a first input voltage, where the first input voltage is an input voltage of the transmitter 10; It is

[0312] the control unit 211 is further configured to adjust the output voltage of the receiver 20 to a first output voltage based on the first input voltage and the first voltage gain.

[0313] As a possible implementation, the receiver 20 may include a voltage regulation module 209. That control unit 211 adjusts the output voltage of the receiver 20 to a first output voltage based on the first input voltage and the first voltage gain includes: the control unit 211 controls, based on the first input voltage and the first voltage gain, the voltage regulation module 209 to adjust the output voltage of the receiver 10 to the first output voltage.

[0314] As a possible implementation, before the control unit 211 adjusts the voltage gain between the output voltage of the receiver 20 and the input voltage of the transmitter 10 for the first voltage gain, the receiving unit 212 is further configured to receive information sent by transmitter 10 and indicating Cp and/or information sent by transmitter 10 and indicating Lp, where Cp and Lp are used by receiver 20 to determine the first voltage gain; and/or the receiving unit 212 is further configured to receive the information sent by the transmitter 10 and which indicates the first voltage gain.

[0315] In this embodiment of this application, the transmitter 10 may further include a DC power source 101 and a DC/AC conversion module 102. The receiver 20 may further include an AC/DC conversion module 203, a power regulator module voltage 204, an output load 205, a modulation module 206, and a battery management system 208. For detailed descriptions of the above modules, refer to the wireless charging system architectures described in Figure 1 and Figure 8. Details no. are described here again.

[0316] In this embodiment of this application, the control unit 109 can be implemented by the control module 105 in the embodiment described in Figure 10. The control unit 211 can be implemented by the control module 207 in the embodiment described in Figure 10. The unit control unit 109 may be a controller 30 in the embodiment described in Figure 19. The control unit 211 may be a controller 40 in the embodiment described in Figure 19. The control unit 109 may also have another function of the control module 105. For details , refer to the embodiment described in Figure 10. The control unit 211 may also have another function of the control module 207. For details, refer to the embodiment described in Figure 10. The functions of the control unit 109, the sending unit 108, of the control unit 211, and the receiving unit 212 may correspond to the corresponding descriptions of the wireless charging method embodiment shown in Figure 11. Details are not described here again.

[0317] Based on the wireless charging system 100 described in Figure 18, in another possible embodiment, the sending unit 108 is configured to send, to the receiver 20, information indicating a first input voltage, where the first voltage input is a transmitter input voltage 10; and the first input voltage is used by the receiver 20 to adjust an output voltage of the receiver 20 to a first output voltage based on the first input voltage and the first voltage gain. The first voltage gain is included in a first load-independent point corresponding to a first degree of coupling and found by transmitter 10 of a first mapping table; or the first voltage gain is included in a first load-independent point corresponding to a first degree of coupling and found by the receiver 20 of a first mapping table; and the first charge-independent point is added to the information indicating the first charge-independent point, and then sent by the receiver to the transmitter 10.

[0318] The first degree of coupling is a degree of coupling between the transmitter coil 104 in the transmitter 10 and the receiver coil 201 in the receiver 20; the first mapping table includes at least one degree of coupling and a load-independent point that corresponds to each of the at least one degree of coupling, and the load-independent point is a combination of a voltage gain and an operating frequency ; and at an operating frequency at a load-independent point corresponding to each degree of coupling, a voltage gain at the load-independent point corresponding to the degree of coupling is independent of an output load of the receiver; It is

[0319] the control unit 109 is further configured to control the first oscillation circuit 107 to transfer power to the receiver 20 at the first voltage gain.

[0320] At the receiver 20, the control unit 211 is configured to find, from a first mapping table, a first load-independent point that corresponds to a first degree of coupling; or

[0321] the receiving unit 212 is configured to receive information sent by the transmitter 10 and which indicates a first charge-independent point, where the first charge-independent point is a first charge-independent point that corresponds to a first degree of coupling and found by transmitter 10 from a first mapping table, where

[0322] the first independent point of load includes a first voltage gain, and the first degree of coupling is a degree of coupling between the transmitter coil 104 in the transmitter 10 and the receiver coil 201 in the receiver 20; the first mapping table includes at least one degree of coupling and a load-independent point that corresponds to each of the at least one degree of coupling, and the load-independent point is a combination of a voltage gain and an operating frequency ; and at an operating frequency at a load-independent point corresponding to each degree of coupling, a voltage gain at the load-independent point corresponding to the degree of coupling is independent of an output load of the receiver;

[0323] the control unit 211 is further configured to adjust a voltage gain between a receiver output voltage 20 and a transmitter input voltage 10 for the first voltage gain; It is

[0324] the control unit 211 is further configured to control the second oscillation circuit 210 to receive the power transferred by the transmitter 10 at the first voltage gain.

[0325] As a possible implementation, the control unit 211 adjusts a voltage gain between a receiver output voltage 20 and a transmitter input voltage 10 for the first voltage gain includes:

[0326] the receiving unit 212 is further configured to receive information sent by the transmitter 10 and which indicates a first input voltage, where the first input voltage is an input voltage of the transmitter 10; It is

[0327] the control unit 211 is further configured to adjust the output voltage of the receiver to a first output voltage based on the first input voltage and the first voltage gain.

[0328] As a possible implementation, before the control unit 211 adjusts the voltage gain between the output voltage of the receiver 20 and the input voltage of the transmitter 10 for the first voltage gain, the receiving unit 212 is further configured to receive information sent by transmitter 10 and indicating Cp and/or information sent by transmitter 10 and indicating Lp, where Cp and Lp are used by receiver 20 to determine the first voltage gain; and/or receive, by receiver 20, the information sent by transmitter 10 and which indicates the first voltage gain.

[0329] In this embodiment of this application, the control unit 109 can be implemented by the control module 105 in the embodiment described in Figure 10. The control unit 211 can be implemented by the control module 207 in the embodiment described in Figure 10. The unit control unit 108 may also have another function of the control module 105. For details, refer to the embodiment described in Figure 10. The control unit 211 may also have another function of the control module 207. For details, refer to the embodiment described in Figure 10. The functions of the control unit 108, the receiving unit 109, the control unit 211, and the sending unit 212 may correspond to the corresponding descriptions of the wireless charging method embodiment shown in Figure 13. Details are not herein described again.

[0330] Based on the system architecture in Figure 1, Figure 19 is a schematic structural diagram of yet another wireless charging system 100 in accordance with an embodiment of this application. The wireless charging system 100 includes a transmitter 10 and a receiver 20.

[0331] As shown in Figure 19, the transmitter 10 includes a transmitter coil 104 and a first series matching capacitor 103, and the transmitter coil 104 is connected to the first series matching capacitor 103 in series to form a first oscillation circuit 107; the first oscillation circuit 107 is configured to transfer power to the receiver 20; and a self-inductance applied when the transmitter coil 104 transfers power to the receiver 20 is Lp, and a capacitance of the first series matching capacitor 103 is Cp, where Lp *Cp =k*Ls *Cs; Ls is a self-inductance applied when a receiver coil 201 in the receiver 20 receives the power transferred by the first oscillation circuit, Cs is a capacitance of a second series matching capacitor 202 in the receiver 20, and k is a positive number that meets 0, 8 < k < 1.2; the receiver coil 201 is connected to a second series matching capacitor 202 in series to form a second oscillation circuit; the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and the transmitter 10 further includes a voltage regulation module 106 configured to regulate an input voltage of the transmitter 10. The transmitter 10 further includes a controller 30, wherein the controller 30 includes:

[0332] one or more processors 301, a memory 302, and a communications interface 303. These components may be connected using a bus 304 or in another mode. A bus connection is used as an example in Figure 19

[0333] Communications interface 303 may be configured for communication between transmitter 10 and another communications device, e.g., receiver 20. Specifically, transmitter 10 and receiver 20 may be the transmitter 10 and receiver 20 shown in Figure 8 or Figure 17. Specifically, communications interface 303 may be an in-band communications interface in the wireless charging system. For detailed descriptions of in-band communication, refer to the modality described in Figure 1.

[0334] Alternatively, the communications interface 303 may be an out-band interface, e.g., a Bluetooth communications interface, a Zigbee communications interface, or a WiFi communications interface, or may be extended to another communications interface. This is not limited to this embodiment of this application.

[0335] Memory 302 is coupled to processor 301, and is configured to store multiple software programs and/or a plurality of instruction sets. Memory 302 may further store a data transmission program. The data transmission program may be used to communicate with one or more additional devices, one or more transmitters, or one or more receivers.

[0336] In some embodiments of this application, memory 302 may be configured to store a program for implementing, on one side of the transmitter 10, the wireless charging method provided in one or more embodiments of this application. For implementation of the wireless charging method provided in one or more embodiments of this application, refer to the embodiments described in Figure 9 and Figure 12.

[0337] Processor 301 may be configured to read and execute a computer-readable instruction. Specifically, the processor 301 may be configured to invoke a program stored in memory 302, e.g., the program to implement, on the transmitter side 10, the wireless charging method provided in one or more embodiments of this application, and execute the instruction included in the program.

[0338] It should be noted that the transmitter 10 shown in Figure 19 is merely an implementation in embodiments of this application. During a real application, the transmitter 10 may further include more or fewer components, and this is not limited here.

[0339] As shown in Figure 19, the receiver 20 includes the receiver coil 201 and the second series matching capacitor 202, the receiver coil 201 is connected to the second series matching capacitor 202 in series to form a second circuit oscillation circuit 210, and the second oscillation circuit 210 is configured to receive the power transferred by the transmitter 10; a self-inductance applied when the receiver coil 201 receives the power transferred by the transmitter 10 is Ls, and a capacitance of the second series matching capacitor 202 is Cs, where ; Lp is a self-inductance applied when the transmitter coil 104 in the transmitter 10 transfers power to the receiver 20, Cp is a capacitance of the first series matching capacitor 103 in the transmitter 10, and k is a positive number that meets 0.8 < k <1.2; the transmitter coil 104 is connected to the first series matching capacitor 103 in series to form the first oscillation circuit 107; and the first oscillation circuit 107 is configured to transfer power to the second oscillation circuit 210.

[0340] The receiver 20 further includes a controller 40, where the controller 40 includes:

[0341] one or more processors 401, a memory 402, and a communications interface 403. These components may be connected using a bus 404 or in another mode. A bus connection is used as an example in Figure 19.

[0342] Communications interface 403 may be configured for communication between receiver 20 and another communications device, e.g., transmitter 10. Specifically, transmitter 10 and receiver 20 may be the transmitter 10 and receiver 20 shown in Figure 8 or Figure 17. Specifically, communications interface 403 may be an in-band communications interface in the wireless charging system. For detailed descriptions of in-band communication, refer to the modality described in Figure 1.

[0343] Alternatively, the communications interface 403 may be an out-band interface, e.g., a Bluetooth communications interface, a Zigbee communications interface, or a WiFi communications interface, or may be extended to another communications interface. This is not limited to this embodiment of this application.

[0344] Memory 402 is coupled to processor 401, and is configured to store multiple software programs and/or a plurality of instruction sets. Memory 402 may further store a data transmission program. The data transmission program may be used to communicate with one or more additional devices, one or more transmitters, or one or more receivers. In some embodiments of this application, memory 402 may be configured to store a program for implementing, on one side of the receiver 20, the wireless charging method provided in one or more embodiments of this application. For implementation of the wireless charging method provided in one or more embodiments of this application, refer to the embodiments described in Figure 9 and Figure 12.

[0345] Processor 401 may be configured to read and execute a computer-readable instruction. Specifically, the processor 401 may be configured to invoke a program stored in memory 402, e.g., the program to implement, on the receiver side 20, the wireless charging method provided in one or more embodiments of this application, and execute the instruction included in the program.

[0346] It should be noted that the receiver 20 shown in Figure 19 is merely an implementation in embodiments of this application. During a real application, the receiver 20 may further include more or fewer components, and this is not limited here.

[0347] The receiver 20 may be a mobile phone, a tablet computer, a computer that has a wireless transceiver function, a virtual reality terminal device, or an augmented reality terminal device. Alternatively, the receiver 20 may be a wireless charging electric vehicle, or white goods, e.g., a cable-free television, a wireless charging soy milk maker, a wireless vacuum cleaning robot, or a drone with multiple rotors.

[0348] Based on the system architecture in Figure 1, Figure 20 is a schematic structural diagram of yet another wireless charging system 100 in accordance with an embodiment of this application. The wireless charging system 100 includes a transmitter 10 and a receiver 20.

[0349] As shown in Figure 20, the transmitter 10 includes a transmitter coil 104 and a first series matching capacitor 103, and the transmitter coil 104 is connected to the first series matching capacitor 103 in series to form a first oscillation circuit 107; the first oscillation circuit 107 is configured to transfer power to the receiver 20; and a self-inductance applied when the transmitter coil 104 transfers power to the receiver 20 is Lp, and a capacitance of the first series matching capacitor 103 is Cp, where Lp *Cp= k*Ls *Cs; Ls is a self-inductance applied when a receiver coil 201 in the receiver 20 receives the power transferred by the first oscillation circuit, Cs is a capacitance of a second series matching capacitor 202 in the receiver 20, and k is a positive number that meets 0, 8 < k < 1.2; the receiver coil 201 is connected to the second series matching capacitor 202 in series to form a second oscillation circuit; the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and the transmitter 10 further includes a controller 50, where the controller 50 includes:

[0350] one or more processors 501, a memory 502, and a communications interface 503. These components may be connected using a bus 504 or in another mode. A bus connection is used as an example in Figure 20.

[0351] Communications interface 503 may be configured for communication between transmitter 10 and another communications device, e.g., receiver 20. Specifically, transmitter 10 and receiver 20 may be the transmitter 10 and receiver 20 shown in Figure 10 or Figure 18. Specifically, the communications interface 503 may be an in-band communications interface in the wireless charging system. For detailed descriptions of in-band communication, refer to the modality described in Figure 1.

[0352] Alternatively, the communications interface 503 may be an out-band interface, e.g., a Bluetooth communications interface, a Zigbee communications interface, or a WiFi communications interface, or may be extended to another communications interface. This is not limited to this embodiment of this application.

[0353] Memory 502 is coupled to processor 501, and is configured to store multiple software programs and/or a plurality of instruction sets. Memory 502 may further store a data transmission program. The data transmission program may be used to communicate with one or more additional devices, one or more transmitters, or one or more receivers.

[0354] In some embodiments of this application, memory 502 may be configured to store a program for implementing, on one side of the transmitter 10, the wireless charging method provided in one or more embodiments of this application. For implementation of the wireless charging method provided in one or more embodiments of this application, refer to the embodiments described in Figure 11 and Figure 13.

[0355] Processor 501 may be configured to read and execute a computer-readable instruction. Specifically, the processor 501 may be configured to invoke a program stored in memory 502, e.g., the program to implement, on the transmitter side 10, the wireless charging method provided in one or more embodiments of this application, and execute the instruction included in the program.

[0356] It should be noted that the transmitter 10 shown in Figure 20 is merely an implementation in embodiments of this application. During a real application, the transmitter 10 may further include more or fewer components, and this is not limited here.

[0357] In this embodiment of this application, the transmitter 10 may further include a DC power source 101 and a DC/AC conversion module 102. The receiver 20 may include an AC/DC conversion module 203, a voltage regulator module 204, an output charge 205, a modulation module 206, and a battery management system 208. For detailed descriptions of the above modules, refer to the wireless charging system architectures described in Figure 1 and Figure 8. Details are not available. described here again.

[0358] As shown in Figure 20, the receiver 20 includes the receiver coil 201 and the second series matching capacitor 202, the receiver coil 201 is connected to the second series matching capacitor 202 in series to form a second circuit oscillation circuit 210, and the second oscillation circuit 210 is configured to receive the power transferred by the transmitter 10; a self-inductance applied when the receiver coil 201 receives the power transferred by the transmitter 10 is Ls, and a capacitance of the second series matching capacitor 202 is Cs, where ; Lp is a self-inductance applied when the transmitter coil 104 in the transmitter 10 transfers power to the receiver 20, Cp is a capacitance of the first series matching capacitor 103 in the transmitter 10, and k is a positive number that meets 0.8 < k <1.2; the transmitter coil 104 is connected to the first series matching capacitor 103 in series to form the first oscillation circuit 107; the first oscillation circuit 107 is configured to transfer power to the second oscillation circuit 210; and the receiver 20 further includes a voltage regulation module 209 configured to regulate an output voltage of the receiver 20.

[0359] The receiver 20 further includes a controller 60, where the controller 60 includes:

[0360] one or more processors 601, a memory 602, and the communications interface 603. These components may be connected using a bus 604 or in another mode. A bus connection is used as an example in Figure 20.

[0361] Communications interface 603 may be configured for communication between receiver 20 and another communications device, e.g., transmitter 10. Specifically, transmitter 10 and receiver 20 may be the transmitter 10 and receiver 20 shown in Figure 10 or Figure 18. Specifically, communications interface 603 may be an in-band communications interface in the wireless charging system. For detailed descriptions of in-band communication, refer to the modality described in Figure 1.

[0362] Alternatively, the communications interface 603 may be an out-band interface, e.g., a Bluetooth communications interface, a Zigbee communications interface, or a WiFi communications interface, or may be extended to another communications interface. This is not limited to this embodiment of this application.

[0363] Memory 602 is coupled to processor 601, and is configured to store multiple software programs and/or a plurality of instruction sets. Memory 602 may further store a data transmission program. The data transmission program may be used to communicate with one or more additional devices, one or more transmitters, or one or more receivers.

[0364] In some embodiments of this application, memory 602 may be configured to store a program for implementing, on one side of the receiver 20, the wireless charging method provided in one or more embodiments of this application. For implementation of the wireless charging method provided in one or more embodiments of this application, refer to the embodiments described in Figure 11 and Figure 13.

[0365] Processor 601 may be configured to read and execute a computer-readable instruction. Specifically, the processor 601 may be configured to invoke the program stored in memory 602, e.g., the program to implement, on the receiver side 20, the wireless charging method provided in one or more embodiments of this application, and execute the instruction included in the program.

[0366] It should be noted that the receiver 20 shown in Figure 20 is merely an implementation in embodiments of this application. During a real application, the receiver 20 may further include more or fewer components, and this is not limited here.

[0367] In this embodiment of this application, the transmitter 10 may further include a DC power source 101 and a DC/AC conversion module 102. The receiver 20 may include an AC/DC conversion module 203, a voltage regulator module 204, an output charge 205, a modulation module 206, and a battery management system 208. For detailed descriptions of the above modules, refer to the wireless charging system architectures described in Figure 1 and Figure 8. Details are not available. described here again.

[0368] It can be understood that when embodiments of this application are applied to a transmitter chip, the transmitter chip implements transmitter functions in the above method embodiment. The transmitter chip sends information to another module (for example, a radio frequency module or an antenna) on the transmitter, and the information is sent to the receiver using the other transmitter module. Alternatively, the transmitter chip may receive the information from another module (e.g., a radio frequency module or an antenna) of the transmitter, and the information is sent to the transmitter by the receiver.

[0369] It can be understood that, when embodiments of this application are applied to a receiver chip, the receiver chip r implements receiver functions in the above method embodiment. The receiver chip sends information to another module (for example, a radio frequency module or an antenna) on the receiver, and the information is sent to the transmitter using the other receiver module. Alternatively, the receiver chip may receive information from another module (e.g., a radio frequency module or an antenna) of the receiver, and the information is sent to the transmitter by the receiver.

[0370] It can be understood that in this application, technical terms and technical solutions between different modalities can be combined or referenced with each other based on internal logic of the different modalities. The embodiments in which technical terms and technical solutions are applied are not limited in this application. A new modality can also be formed by mutually combining the technical solutions in the different modalities.

[0371] It can be understood that the processor in embodiments of this application may be a Central Processing Unit (CPU), or may be another general purpose processor, a Digital Signal Processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a transistor logic device, a hardware component, or any of its combination. The general purpose processor can be a microprocessor or any conventional processor.

[0372] The method steps in embodiments of this application may be implemented by hardware, or may be implemented by a processor that executes a software instruction. The software instruction may include a corresponding software module. The software module may be located in a random access memory (RAM), an instant memory, a read-only memory (ROM), a programmable read-only memory (PROM). ), an erasable programmable read-only memory (Erasable PROM, EPROM), an electrically erasable programmable read-only memory (Electrically EPROM, EEPROM), a register, a hard disk, a removable hard disk, a CD-ROM, or a storage medium in any other manner known in the art. For example, a storage medium is coupled to a processor so that the processor can read information from the storage medium or write information to the storage medium. Of course, the storage medium can be a component of the processor. The processor and storage medium can be located in the ASIC. Furthermore, the ASIC can be located on a sending device or a receiving device. Of course, the processor and the storage medium may exist in the sending device or the receiving device as discrete components.

[0373] All or some of the above embodiments can be implemented using software, hardware, firmware or any combination thereof. When software is used to implement the embodiments, the embodiments may be implemented completely or partially in a form of a computer program product. The computer program product includes one or more computer instructions. When computer instructions are loaded and executed on a computer, the procedures or functions according to embodiments of this application are all or partially generated. The computer may be a general purpose computer, a dedicated computer, a computer network, or other programmable device. Computer instructions may be stored on a computer-readable storage medium or transmitted using the computer-readable storage medium. Computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired fashion (for example, a coaxial cable, an optical fiber, or a wired line). subscriber (DSL)) or wireless (e.g. infrared, radio or microwave). The computer-readable storage medium can be any usable medium accessible by a computer, or a data storage device, such as a server or a data center, that integrates one or more usable media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard drive, or a magnetic tape), an optical medium (e.g., a DVD), a semiconductor medium (e.g., a solid-state disk (e.g., a solid state disk). Solid State Disk, SSD)), or similar.

[0374] A person skilled in the art can understand that all or some of the procedures of the methods in the above embodiments can be implemented by a computer program that instructs relative hardware. The program can be stored on the computer-readable storage medium. When the program executes, the procedures of the above method embodiments are executed. The above storage medium includes: any medium that can store program code, such as a ROM, a RAM random access memory, a magnetic disk or an optical disk.

Claims (30)

1. Wireless charging system, characterized by the fact that: the wireless charging system (100) comprises a transmitter (10) and a receiver (20); the transmitter comprises a transmitter coil (104) and a first series matching capacitor (103), the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit oscillation is configured to transfer power to the receiver; and the receiver comprises a receiver coil (201) and a second series matching capacitor (202), the receiver coil is connected to the second series matching capacitor in series to form a second oscillation circuit, and the second circuit oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp; and a self-inductance applied when the receiver coil receives the power transferred by the first oscillation circuit is Ls, and a capacitance of the second matching capacitor in series is Cs, where , and k is a positive number that meets 0.8 < k < 1.2, where when a voltage gain between a receiver output voltage and a transmitter input voltage is a first voltage gain, the charging system wireless operates at an independent point of charge; the load independent point is determined by a first operating frequency and the first voltage gain; at the first operating frequency, the first voltage gain is independent of a receiver output load; and the first voltage gain is X, and X is a positive number that meets , or X is a positive number that meets 2. Wireless charging system according to claim 1, characterized by the fact that: k is 1, and X is or 3. Wireless charging system according to any one of claims 1 to 2, characterized by the fact that: the transmitter further comprises a first voltage regulation module (106), to which the first voltage regulation module is connected to the first parallel oscillation circuit; and the first voltage regulation module is configured to adjust the voltage gain between the output voltage of the receiver and the input voltage of the transmitter to the first voltage gain when regulating the input voltage of the transmitter. 4. Wireless charging system according to any one of claims 1 to 3, characterized by the fact that: the receiver further comprises a second voltage regulation module (209), to which the second voltage regulation module is connected to the second parallel oscillation circuit; and the second voltage regulation module is configured to adjust the voltage gain between the receiver output voltage and the transmitter input voltage to the first voltage gain when regulating the receiver output voltage. 5. Transmitter, characterized by the fact that: the transmitter (10) comprises a transmitter coil (104) and a first series matching capacitor (103), and the transmitter coil is connected to the first series matching capacitor in series series to form a first oscillation circuit; the first oscillation circuit is configured to transfer power to a receiver (20); and a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp, where Lp *Cp =k*Ls *Cs ; Ls is a self-inductance applied when a receiver coil (201) in the receiver receives the power transferred by the first oscillation circuit, Cs is a capacitance of a second series matching capacitor (202) in the receiver, and k is a positive number that meets 0.8 < k <1.2; the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit; and the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit, wherein when a voltage gain between a receiver output voltage and a transmitter input voltage is a first voltage gain, a wireless charging (100) operates at an independent charging point; the wireless charging system comprises the transmitter and the receiver, the independent charging point is determined by a first operating frequency and the first voltage gain; at the first operating frequency, the first voltage gain is independent of a receiver output load; and the first voltage gain is X, and X is a positive number that meets or X is a positive number that meets 6. Transmitter according to claim 5, characterized by the fact that: k is 1, and X is or 7. Transmitter according to any one of claims 5 to 6, characterized in that: the transmitter further comprises a voltage regulation module (106), wherein the voltage regulation module is connected to the first oscillation circuit in parallel; and the voltage regulation module is configured to adjust the voltage gain between the receiver output voltage and the transmitter input voltage to the first voltage gain when regulating the transmitter input voltage. 8. Receiver, characterized by the fact that: the receiver (20) comprises a receiver coil (201) and a second series matching capacitor (202), the receiver coil is connected to the second series matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive power transferred by a transmitter (10); and a self-inductance applied when the receiver coil receives the power transferred by the transmitter is Ls, and a capacitance of the second matching capacitor in series is Cs, where ; Lp is a self-inductance applied when a transmitter coil (104) in the transmitter transfers power to the receiver, Cp is a capacitance of a first series matching capacitor (103) in the transmitter, and k is a positive number that meets 0.8 < k <1.2; the transmitter coil is connected to the first matching capacitor in series in series to form a first oscillation circuit; and the first oscillation circuit is configured to transfer power to the second oscillation circuit, wherein when a voltage gain between a receiver output voltage and a transmitter input voltage is a first voltage gain, a system of wireless charging (100) operates at an independent charging point; the wireless charging system comprises the transmitter and the receiver, the independent charging point is determined by a first operating frequency and the first voltage gain; at the first operating frequency, the first voltage gain is independent of a receiver output load; and the first voltage gain is X, and X is a positive number that meets , or X is a positive number that meets 9. Receiver according to claim 8, characterized by the fact that: k is 1, and X is or 10. Receiver according to any one of claims 8 to 9, characterized in that: the receiver further comprises a voltage regulation module (209), wherein the voltage regulation module is connected to the second oscillation circuit in parallel; and the voltage regulation module is configured to adjust the voltage gain between the receiver output voltage and the transmitter input voltage to the first voltage gain when regulating the receiver output voltage. 11. Charging method based on a wireless charging system, characterized by the fact that: the wireless charging system (100) comprises a transmitter (10) and a receiver (20); the transmitter comprises a transmitter coil (104) and a first series matching capacitor (103), the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit oscillation is configured to transfer power to the receiver; the receiver comprises a receiver coil (201) and a second series matching capacitor (202), the receiver coil is connected to the second series matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit oscillation is configured to receive the power transferred by the first oscillation circuit; a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp; a self-inductance applied when the receiver coil receives the power transferred by the first oscillation circuit is Ls, and a capacitance of the second matching capacitor in series is Cs, where , and k is a positive number that meets 0.8 < k <1.2; and the method comprises: adjusting, by the transmitter, a voltage gain between a receiver output voltage and a transmitter input voltage for a first voltage gain, wherein the first voltage gain is X, and X is a number positive that meets , or X is a positive number that meets ; when the voltage gain between the receiver output voltage and the transmitter input voltage is the first voltage gain, the wireless charging system operates at an independent charge point; the load independent point is determined by a first operating frequency and the first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; and transfer, through the transmitter, the power to the receiver at the first voltage gain. 12. Method according to claim 11, characterized by the fact that: k is 1, and X is or 13. Method according to claim 11 or 12, characterized by the fact that: adjusting, by the transmitter, a voltage gain between a receiver output voltage and a transmitter input voltage for a first voltage gain comprising : receiving, by the transmitter, information sent by the receiver and indicating a first output voltage, wherein the first output voltage is an expected output voltage of the receiver; and adjusting, by the transmitter, the input voltage of the transmitter to a first input voltage based on the first output voltage and the first voltage gain. 14. Method according to any one of claims 11 to 13, characterized in that: before adjusting, by the transmitter, a voltage gain between a receiver output voltage and a transmitter input voltage for a first gain of voltage, the method further comprises: receiving, by the transmitter, information sent by the receiver and indicating Cs and/or information sent by the receiver and indicating Ls, wherein Cs and Ls are used by the transmitter to determine the first voltage gain; and/or receive, through the transmitter, information sent by the receiver and indicating the first voltage gain. 15. Charging method based on a wireless charging system, characterized by the fact that: the wireless charging system (100) comprises a transmitter (10) and a receiver (20); the transmitter comprises a transmitter coil (104) and a first series matching capacitor (103), the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit oscillation is configured to transfer power to the receiver; the receiver comprises a receiver coil (201) and a second series matching capacitor (202), the receiver coil is connected to the second series matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit oscillation is configured to receive the power transferred by the first oscillation circuit; a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp; a self-inductance applied when the receiver coil receives the power transferred by the first oscillation circuit is Ls, and a capacitance of the second matching capacitor in series is Cs, where , and k is a positive number that meets 0.8 < k <1.2; and the method comprises: sending, by the receiver to the transmitter, information indicating a first output voltage, wherein the first output voltage is an expected output voltage of the receiver, and the first output voltage is used by the transmitter to adjust a transmitter input voltage to a first input voltage based on the first output voltage and a first voltage gain, wherein the first voltage gain is , or X is a positive number that meets when a voltage gain between a receiver output voltage and a transmitter input voltage is the first voltage gain, the wireless charging system operates at a charge-independent point; the load independent point is determined by a first operating frequency and the first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; and receive, through the receiver, the power transferred by the transmitter in the first voltage gain. 16. Charging method based on a wireless charging system, characterized by the fact that: the wireless charging system (100) comprises a transmitter (10) and a receiver (20); the transmitter comprises a transmitter coil (104) and a first series matching capacitor (103), the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit oscillation is configured to transfer power to the receiver; the receiver comprises a receiver coil (201) and a second series matching capacitor (202), the receiver coil is connected to the second series matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit oscillation is configured to receive the power transferred by the first oscillation circuit; a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp; a self-inductance applied when the receiver coil receives the power transferred by the first oscillation circuit is Ls, and a capacitance of the second matching capacitor in series is Cs, where , and k is a positive number that meets 0.8 < k <1.2; and the method comprises: adjusting, by the receiver, a voltage gain between a receiver output voltage and a transmitter input voltage for a first voltage gain, wherein the first voltage gain is X, and X is a number positive that meets , or X is a positive number that meets ; when the voltage gain between the receiver output voltage and the transmitter input voltage is the first voltage gain, the wireless charging system operates at an independent charge point; the load independent point is determined by a first operating frequency and the first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; and receive, through the receiver, the power transferred by the transmitter in the first voltage gain. 17. Method according to claim 16, characterized by the fact that: k is 1, and X is or 18. Method according to claim 16 or 17, characterized by the fact that: adjusting, by the receiver, a voltage gain between a receiver output voltage and a transmitter input voltage for a first voltage gain comprising : receiving, by the receiver, information sent by the transmitter and indicating a first input voltage, wherein the first input voltage is the transmitter input voltage; and adjusting, by the receiver, the output voltage of the receiver to a first output voltage based on the first input voltage and the first voltage gain. 19. Method according to any one of claims 16 to 18, characterized in that: before adjusting, by the receiver, a voltage gain between a receiver output voltage and a transmitter input voltage for a first gain of voltage, the method further comprises: receiving, by the receiver, information sent by the transmitter and indicating Cp and/or information sent by the transmitter and indicating Lp, wherein Cp and Lp are used by the receiver to determine the first voltage gain; and/or receive, by the receiver, information sent by the transmitter and indicating the first voltage gain. 20. Charging method based on a wireless charging system, characterized by the fact that: the wireless charging system (100) comprises a transmitter (10) and a receiver (20); the transmitter comprises a transmitter coil (104) and a first series matching capacitor (103), the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit, and the first oscillation circuit oscillation is configured to transfer power to the receiver; the receiver comprises a receiver coil (201) and a second series matching capacitor (202), the receiver coil is connected to the second series matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit oscillation is configured to receive the power transferred by the first oscillation circuit; a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp; a self-inductance applied when the receiver coil receives the power transferred by the first oscillation circuit is Ls, and a capacitance of the second matching capacitor in series is Cs, where , and k is a positive number that meets 0.8 < k <1.2; and the method comprises: sending, by the transmitter to the receiver, information indicating a first input voltage, wherein the first input voltage is an input voltage of the transmitter; and the first input voltage is used by the receiver to adjust an output voltage of the receiver to a first output voltage based on the first input voltage and a first voltage gain, wherein the first voltage gain is X is a positive number that meets or X is a positive number that meets when a voltage gain between the receiver output voltage and the transmitter input voltage is the first voltage gain, the wireless charging system operates at an independent charge point; the load independent point is determined by a first operating frequency and the first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; and transfer, through the transmitter, the power to the receiver at the first voltage gain. 21. Transmitter, characterized by the fact that: the transmitter (10) comprises a transmitter coil (104) and a first series matching capacitor (103), and the transmitter coil is connected to the first series matching capacitor in series to form a first oscillation circuit; the first oscillation circuit is configured to transfer power to a receiver (20); and a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp, where Lp *Cp =k*Ls *Cs ; Ls is a self-inductance applied when a receiver coil (201) in the receiver receives the power transferred by the first oscillation circuit, Cs is a capacitance of a second series matching capacitor (202) in the receiver, and k is a positive number that meets 0.8 < k <1.2; the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit; the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and the transmitter further comprises: a control unit (108), configured to adjust a voltage gain between a receiver output voltage and a transmitter input voltage for a first voltage gain, wherein the first voltage gain is X, and X is a positive number that meets or X is a positive number that meets when the voltage gain between the receiver output voltage and the transmitter input voltage is the first voltage gain, the wireless charging system operates at an independent charge point; the load independent point is determined by a first operating frequency and the first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; and the control unit is further configured to control the first oscillation circuit to transfer power to the receiver at the first voltage gain. 22. Transmitter according to claim 21, characterized by the fact that: k is 1, and X is or 23. Transmitter according to claim 21 or 22, characterized by the fact that: the transmitter further comprises a receiving unit (109), and the receiving unit is configured to receive information sent by the receiver and indicating a first output voltage , wherein the first output voltage is an expected output voltage of the receiver; and the control unit is further configured to adjust the input voltage of the transmitter to a first input voltage based on the first output voltage and the first voltage gain. 24. Transmitter according to any one of claims 21 to 23, characterized in that: before the control unit adjusts the voltage gain between the receiver output voltage and the transmitter input voltage for the first voltage gain , the receiving unit is further configured to receive information sent by the receiver and indicating Cs and/or information sent by the receiver and indicating Ls, wherein Cs and Ls are used by the transmitter to determine the first voltage gain; and/or the receiving unit is configured to receive information sent by the receiver and indicating the first voltage gain. 25. Receiver, characterized by the fact that: the receiver (20) comprises a receiver coil (201) and a second series matching capacitor (202), the receiver coil is connected to the second series matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive power transferred by a transmitter (10); and a self-inductance applied when the receiver coil receives the power transferred by the transmitter is Ls, and a capacitance of the second matching capacitor in series is Cs, where ; Lp is a self-inductance applied when a transmitter coil (104) in the transmitter transfers power to the receiver, Cp is a capacitance of a first series matching capacitor (103) in the transmitter, and k is a positive number that meets 0.8 < k <1.2; the transmitter coil is connected to the first matching capacitor in series in series to form a first oscillation circuit; and the first oscillation circuit is configured to transfer power to the second oscillation circuit; the receiver further comprises a sending unit (212) and a control unit (211), wherein the sending unit is configured to send, to the transmitter, information indicating a first output voltage, wherein the first output voltage output is an expected output voltage of the receiver, and the first output voltage is used by the transmitter to adjust a transmitter input voltage to a first input voltage based on the first output voltage and a first voltage gain, in that the first voltage gain is X, and X is a positive number that meets or X is a positive number that meets when a voltage gain between a receiver output voltage and a transmitter input voltage is the first voltage gain, the wireless charging system operates at a charge-independent point; the load independent point is determined by a first operating frequency and the first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; and the control unit is configured to control the second oscillation circuit to receive the power transferred by the transmitter at the first voltage gain. 26. Receiver, characterized by the fact that: the receiver (20) comprises a receiver coil (201) and a second series matching capacitor (202), the receiver coil is connected to the second series matching capacitor in series to form a second oscillation circuit, and the second oscillation circuit is configured to receive power transferred by a transmitter (10); and a self-inductance applied when the receiver coil receives the power transferred by the transmitter is Ls, and a capacitance of the second matching capacitor in series is Cs, where ; Lp is a self-inductance applied when a transmitter coil (104) in the transmitter transfers power to the receiver, Cp is a capacitance of a first series matching capacitor (103) in the transmitter, and k is a positive number that meets 0.8 < k <1.2; the transmitter coil is connected to the first matching capacitor in series in series to form a first oscillation circuit; and the first oscillation circuit is configured to transfer power to the second oscillation circuit; the receiver further comprises a control unit (211), wherein the control unit is configured to adjust a voltage gain between a receiver output voltage and a transmitter input voltage for a first voltage gain, wherein the first voltage gain is X, and X is a positive number that meets , or X is a positive number that meets ; when the voltage gain between the receiver output voltage and the transmitter input voltage is the first voltage gain, the wireless charging system operates at an independent charge point; the load independent point is determined by a first operating frequency and the first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; and the control unit is further configured to control the second oscillation circuit to receive the power transferred by the transmitter at the first voltage gain. 27. Receiver according to claim 26, characterized by the fact that: k is 1, and X is or 28. Receiver according to claim 26 or 27, characterized in that: the receiver further comprises a receiving unit (212), and that a control unit adjusts a voltage gain between an output voltage of the receiver and a transmitter input voltage for a first voltage gain comprises: the receiving unit being configured to receive information sent by the transmitter and indicating a first input voltage, wherein the first input voltage is the transmitter input voltage; and the control unit is further configured to adjust the output voltage of the receiver to a first output voltage based on the first input voltage and the first voltage gain. 29. Receiver according to any one of claims 26 to 28, characterized in that: before the control unit adjusts the voltage gain between the receiver output voltage and the transmitter input voltage for the first voltage gain , the receiving unit is further configured to receive information sent by the transmitter and indicating Cp and/or information sent by the transmitter and indicating Lp, wherein Cp and Lp are used by the receiver to determine the first voltage gain; and/or the receiving unit is further configured to receive information sent by the transmitter and indicating the first voltage gain. 30. Transmitter, characterized by the fact that: the transmitter (10) comprises a transmitter coil (104) and a first series matching capacitor (103), and the transmitter coil is connected to the first series matching capacitor in series series to form a first oscillation circuit; the first oscillation circuit is configured to transfer power to a receiver (20); and a self-inductance applied when the transmitter coil transfers power to the receiver is Lp, and a capacitance of the first matching capacitor in series is Cp, where Lp *Cp =k*Ls *Cs ; Ls is a self-inductance applied when a receiver coil (201) in the receiver receives the power transferred by the first oscillation circuit, Cs is a capacitance of a second series matching capacitor (202) in the receiver, and k is a positive number that meets 0.8 < k <1.2; the receiver coil is connected to the second matching capacitor in series to form a second oscillation circuit; the second oscillation circuit is configured to receive the power transferred by the first oscillation circuit; and the transmitter further comprises a control unit (109) and a sending unit (108), wherein the sending unit is configured to send, to the receiver, information indicating a first input voltage, wherein the first voltage input is a transmitter input voltage; and the first input voltage is used by the receiver to adjust an output voltage of the receiver to a first output voltage based on the first input voltage and a first voltage gain, wherein the first voltage gain is X is a positive number that meets , or X is a positive number that meets when a voltage gain between the receiver output voltage and the transmitter input voltage is the first voltage gain, the wireless charging system operates at an independent charge point; the load independent point is determined by a first operating frequency and the first voltage gain; and at the first operating frequency, the first voltage gain is independent of a receiver output load; and the control unit is configured to control the first oscillation circuit to transfer power to the receiver at the first voltage gain.