Wireless charging receiver, transmitter, system, and control method, and electric vehicle

1 . A wireless charging receiver comprising:

a power receive coil configured to convert an alternating magnetic field transmitted by a power transmit coil at a wireless charging transmitter into alternating current:

a low-frequency magnetic field receive coil configured to convert a low-frequency magnetic field, transmitted by low-frequency magnetic field transmit coils, into a first induced signal for use in measuring alignment of the power receive coil and the power transmit coil:

a receiver controller configured to:

instruct the wireless charging transmitter to stop transmission of the low-frequency magnetic field based on information derived from the first induced signal being inadequate to determine relative positions of the power receive coil and the power transmit coil,

receive information from the wireless charging transmitter indicating the low-frequency magnetic field transmit coils have stopped working,

update allocation of signal features for the low-frequency magnetic field transmit coils,

wherein each low-frequency transmit coil is assigned a signal feature different from other low-frequency magnetic field transmit coils,

send the updated allocation to the wireless charging transmitter, and

determine, based on the low-frequency magnetic field transmit coils using the updated allocation, the relative positions of the power transmit coil and the power receive coil by using a second induced signal based on the signal features allocated to the low-frequency magnetic field transmit coils.

2 . The wireless charging receiver according to claim 1 , wherein the updated allocation of signal features is a preset allocation based on the low-frequency magnetic field transmit coils having stopped working and no signal feature from the first induced signal is obtained.

3 . The wireless charging receiver according to claim 1 , wherein the receiver controller is further configured to:

send an alignment guiding request to the wireless charging transmitter, wherein the alignment guiding request is used to request the wireless charging transmitter to guide alignment; and

receive first response information sent by the wireless charging transmitter, wherein the first response information comprises parameters of the low-frequency magnetic field transmit coils.

4 . The wireless charging receiver according to claim 1 , wherein the updated allocation is further used to request the wireless charging transmitter control the low-frequency magnetic field transmit coils to start working using the updated allocation.

5 . The wireless charging receiver according to claim 3 , wherein the parameters comprise identification information of the low-frequency magnetic field transmit coils, size information, and relative position information of the low-frequency magnetic field transmit coils and the power transmit coil.

6 . The wireless charging receiver according to claim 1 , wherein a signal feature among the signal features is one of the following: a signal pulse width, a signal code, and a signal frequency, and wherein the wireless charging receiver further includes:

a receiver capacitor connected in parallel with the low-frequency magnetic field receive coil to form a pair,

wherein the pair form a parallel resonant circuit, and

wherein a parallel resonance frequency of the pair is the same as a series resonance frequency of a pair comprising one of the low-frequency magnetic field transmit coils and a transmitter capacitor of a wireless transmitter.

7 . The wireless charging receiver according to claim 6 , further comprising a detection circuit

wherein an input terminal of the detection circuit is connected to the low-frequency magnetic field receive coil, and an output terminal of the detection circuit is connected to the receiver controller; and

wherein the detection circuit is configured to obtain an amplitude of the induced signal and the signal feature of the induced signal and send the amplitude and the signal feature to the receiver controller.

8 . A wireless charging transmitter comprising an inverter circuit, a transmitter controller, a power transmit coil and a low-frequency magnetic field transmit coils, wherein

the power transmit coil is configured to transmit alternating current in a form of an alternating magnetic field:

the inverter circuit is configured to convert direct current into alternating current and to supply the alternating current to the low-frequency magnetic field transmit coils:

the low-frequency magnetic field transmit coils are configured to transmit the alternating current in a form of a low-frequency magnetic field:

the transmitter controller is configured to:

receive, a correspondence, from a wireless charging receiver, between each low-frequency magnetic field transmit coil and an allocated signal feature and an instruction to stop transmission;

control the inverter circuit to stop operation of the low-frequency magnetic field transmit coils in response to the instruction;

receive, from the wireless charging receiver after the low-frequency magnetic field transmit coils have stopped working, an updated allocation of signal features to the low-frequency magnetic field transmit coils,

wherein each low-frequency magnetic field transmit coil is assigned a signal feature different from signal features assigned to other low-frequency magnetic field transmit coils; and

control the inverter circuit to operate the low-frequency magnetic field transmit coils using the updated allocation of signal features such that induced signals generated at the wireless charging receiver are distinguishable for determining relative positions of the power transmit coil and a power receive coil.

9 . The wireless charging transmitter according to claim 8 , wherein the signal feature is one of the following: a signal pulse width, a signal code and a signal frequency.

10 . The wireless charging transmitter according to claim 9 , further comprising: a transmitter capacitor:

wherein each low-frequency magnetic field transmit coil is connected in series to one transmitter capacitor; and

wherein the transmitter capacitor is configured to form a series resonant circuit jointly with the low-frequency magnetic field transmit ceil coils.

11 . The wireless charging transmitter according to claim 10 , wherein the signal feature is the signal pulse width, and the transmitter controller is further configured to:

adjust a duty cycle and/or a frequency of a control signal of a switching transistor in the inverter circuit based on the correspondence, so that the low-frequency magnetic field transmit coils transmit low-frequency magnetic fields at different times,

wherein the low-frequency magnetic field is used to make each low-frequency magnetic field receive coil generate an induced signal having the allocated signal pulse width.

12 . The wireless charging transmitter according to claim 10 , wherein the signal feature is the signal code, and the transmitter controller is further configured to:

adjust a control signal of a switching transistor in the inverter circuit based on the correspondence, so that the low-frequency magnetic field transmit coils transmits a low-frequency magnetic field based on preset duration or stops working based on a preset interruption time.

13 . The wireless charging transmitter according to claim 9 , wherein the signal feature is the signal frequency, and each low-frequency magnetic field transmit coil is connected in series to one frequency adjustment circuit,

wherein each frequency adjustment circuit comprises at least two frequency adjustment branches connected in parallel, and each frequency adjustment branch comprises a transmitter capacitor and a switch that are connected in series; and

wherein the transmitter controller is further configured to:

control a working status of the switch in each frequency adjustment branch based on the correspondence, so that a series resonance frequency of the low-frequency magnetic field transmit coils and the connected transmitter capacitor is the same as the signal frequency allocated to the low-frequency magnetic field transmit coils; and

adjust a duty cycle and/or a frequency of a control signal of a switching transistor in the inverter circuit, so that each low-frequency magnetic field transmit coil transmits the low-frequency magnetic field.

14 . A wireless charging control method, applied to a wireless charging receiver comprising a receiver controller, a power receive coil, and a low-frequency magnetic field receive coil, wherein the power receive coil is configured to convert an alternating magnetic field transmitted by a power transmit coil into alternating current, and wherein the low-frequency magnetic field receive coil is configured to convert a low-frequency magnetic field into an induced signal, and the method comprises:

obtaining a first induced signal from the low-frequency magnetic field receive coil:

determining, based on information derived from the first induced signal, that relative positions of the power receive coil and the power transmit coil cannot be determined;

instructing a wireless charging transmitter to stop transmission of the low-frequency magnetic field in response to the determination;

receiving information from the wireless charging transmitter indicating the low-frequency magnetic field transmit coils have stopped working;

updating an allocation of signal features to the low-frequency magnetic field transmit coils,

wherein each low-frequency magnetic field transmit coil is assigned a signal feature different from signal features assigned to other low-frequency magnetic field transmit coils;

sending information relating each low-frequency magnetic field transmit coil and its allocated signal feature to the wireless charging transmitter; and

determining relative positions of a power transmit coil and a power receive coil by using a second induced signal generated by operation of the low-frequency magnetic field transmit coils using the updated allocation of signal features.

15 . The method according to claim 14 , further comprising:

based on the low-frequency magnetic field transmit coils having stopped working and no signal feature from the first induced signal is obtained, the signal feature allocated to each low-frequency magnetic field transmit coil is a preset signal feature.

16 . The method according to claim 14 , wherein the signal feature is one of the following: a signal pulse width, a signal code, and a signal frequency.

17 . A wireless charging control method, applied to a wireless charging transmitter comprising an inverter circuit, a transmitter controller, a power transmit coil, and a low-frequency magnetic field transmit coils, wherein the power transmit coil is configured to transmit alternating current in a form of an alternating magnetic field, wherein the inverter circuit is configured to convert direct current into alternating current and to supply the alternating current to the low-frequency magnetic field transmit coil coils, and wherein the low-frequency magnetic field transmit coils are configured to transmit the alternating current in a form of a low-frequency magnetic field, and the method comprises:

receiving, from a wireless charging receiver, an instruction to stop transmission of the low-frequency magnetic field;

controlling an inverter circuit to stop operation of the low-frequency magnetic field transmit coils in response to the instruction,

after the low-frequency magnetic field transmit coils have stopped operating, receiving, from the wireless charging receiver, an updated allocation of signal features to the low-frequency magnetic field transmit coils,

wherein each low-frequency magnetic field transmit coil is assigned a signal feature different from signal features assigned to other low-frequency magnetic field transmit coils;

controlling the inverter circuit to operate the low-frequency magnetic field transmit coils using the updated allocation of signal features; and

transmitting the low-frequency magnetic field using the updated allocation such that induced signals at the wireless charging receiver are distinguishable for determining relative positions of the power transmit coil and a power receive coil.

18 . A wireless charging system comprising:

a wireless charging receiver, and a wireless charging transmitter,

wherein the wireless charging receiver comprises a receiver controller, a power receive coil, and low-frequency magnetic field receive coils, and

wherein the power receive coil is configured to convert an alternating magnetic field transmitted by a power transmit coil into alternating current:

each of the low-frequency magnetic field receive coil is configured to convert a low-frequency magnetic field into an induced signal:

the receiver controller is configured to, based on the low-frequency magnetic field transmit coils having stopped working, allocate a signal feature different from that of a current induced signal to each low-frequency magnetic field transmit coil, and send a correspondence between each low-frequency magnetic field transmit coil and the allocated signal feature to the wireless charging transmitter:

the receiver controller is further configured to determine, based on the low-frequency magnetic field transmit coils working, relative positions of the power transmit coil and the power receive coil by using an induced signal having the allocated signal feature;

wherein the wireless charging transmitter comprises an inverter circuit, a transmitter controller, a power transmit coil, and a low-frequency magnetic field transmit coil, and

wherein the power transmit coil is configured to transmit alternating current in a form of an alternating magnetic field;

the inverter circuit is configured to convert direct current into alternating current and then transmit the alternating current to the low-frequency magnetic field transmit coils;

the low-frequency magnetic field transmit coils are configured to transmit the alternating current in a form of a low-frequency magnetic field; and

the transmitter controller is configured to receive the correspondence, sent by the wireless charging receiver, between each low-frequency magnetic field transmit coil and an allocated signal feature, and is further configured to control the inverter circuit based on the correspondence to enable each low-frequency magnetic field transmit coil to work,

wherein the allocated signal feature is a signal feature that is allocated by a receiver controller to each low-frequency magnetic field transmit coil based on all low-frequency magnetic field transmit coils stop working and that is different from that of a current induced signal.

19 . An electric vehicle comprising:

a wireless charging receiver;

a power battery pack configured to electrically connect to the wireless charging receiver for charging by using electric energy from the wireless charging receiver, and to provide electric energy for operation of the electric vehicle;

a power receive coil configured to convert an alternating magnetic field transmitted by a power transmit coil into alternating current:

a low-frequency magnetic field receive coil configured to convert a low-frequency magnetic field, transmitted by low-frequency magnetic field transmit coils, into an induced signal; and

a receiver controller configured to:

instruct a wireless charging transmitter to stop transmission of the low-frequency magnetic field based on information derived from the first induced signal being inadequate to determine relative positions of the power receive coil and the power transmit coil;

receive information from the wireless charging transmitter indicating that all of the low-frequency magnetic field transmit coils have stopped working;

update allocation of signal features for the low-frequency magnetic field transmit coils, wherein each low-frequency magnetic field transmit coil is assigned a signal feature different from signal features assigned to other low-frequency magnetic field transmit coils;

send the updated allocation of correspondence between each low-frequency magnetic field transmit coil and the allocated signal feature to the wireless charging transmitter; and

determine, based on operation of the low-frequency magnetic field transmit coils using the updated allocation, relative positions of the power transmit coil and the power receive coil by using a second induced signal.