CN114643883A

CN114643883A - Wireless charging method for electric automobile

Info

Publication number: CN114643883A
Application number: CN202210560967.XA
Authority: CN
Inventors: 鲁国希; 陆钧; 王哲; 贺凡波; 葛俊杰; 马俊超
Original assignee: Hefei Yougan Technology Co ltd
Current assignee: Hefei Yougan Technology Co ltd
Priority date: 2022-05-23
Filing date: 2022-05-23
Publication date: 2022-06-21
Anticipated expiration: 2042-05-23
Also published as: CN114643883B

Abstract

The invention discloses a wireless charging method for an electric automobile, which comprises the following steps: the first stage is divided into: step S10, the vehicle to be charged reaches the first position; step S11, establishing a first connection between the vehicle to be charged and the charging management system; step S12, compatibility pre-checking; the second stage comprises the following steps: step S20, reaching the second position; step S21, identifying the service set identification of the target ground communication control unit; the third stage is as follows: step S30, reaching a third position; step S31, establishing a third connection between an auxiliary transmitting coil and an auxiliary receiving coil of the vehicle to be charged, and the like; the fourth stage is divided into: step 50, verifying whether the vehicle to be charged is successfully paired with the charging position; the fifth stage comprises the following steps: a detection step; step S71, initiating a charging request; step S72 starts charge transmission. The three connections are established in the first three stages, so that the whole process from the searching of the charging parking space to the starting of charging of the vehicle to be charged is completed, and the matching between the vehicle to be charged and the charging parking space can be efficiently and quickly completed.

Description

Wireless charging method for electric automobile

Technical Field

The invention relates to the field of wireless charging, in particular to a wireless charging method for an electric automobile.

Background

When the electric automobile adopts wireless charging, the wireless charging device does not need physical connection with a power supply, so that the wireless charging has a very good application prospect due to flexibility, convenience and higher safety. When the wireless charging system is deployed in a large quantity, a charging station is formed, and a plurality of electric vehicles can be charged wirelessly at the same time. Due to the fact that a charging gun does not need to be inserted during charging in wireless charging, and no physical connection exists between vehicle-mounted equipment and ground equipment of the wireless charging system of the electric automobile, a method for searching and matching a charging parking space with adaptive charging equipment at a charging station needs to be provided for a vehicle to be charged, matching accuracy of the vehicle-mounted equipment and the ground equipment needs to be verified before parking and charging, and therefore safety of wireless charging is guaranteed.

Disclosure of Invention

The invention provides a wireless charging method for an electric automobile, which can efficiently match a charging parking space for a vehicle to be charged.

The wireless charging method of the electric automobile comprises the following steps: a first stage, which is divided into the following steps: step S10, the vehicle to be charged reaches the first position; step S11, establishing a first connection between the vehicle to be charged and the charging management system; step S12, compatibility pre-check is carried out, and the next step is carried out after the pre-check is successful; step S13, selecting a charging parking space; and the second stage comprises the following steps: step S20, reaching the second position; step S21, identifying the service set identification of the target ground communication control unit; step S22, the vehicle to be charged and the target ground communication control unit establish a second connection; step S23, checking compatibility finally, and entering the next step after checking successfully; step S24, entering a guiding alignment stage; a third stage, which is divided into the following steps: step S30, reaching a third position; step S31, establishing a third connection between an auxiliary transmitting coil and an auxiliary receiving coil of the vehicle to be charged; step S32, completing guide alignment; a fourth stage, which is divided into the following steps: step S50, verifying whether the vehicle to be charged is successfully paired with the charging, entering the next stage if the pairing is successful, and returning to the first stage if the pairing is not successful; a fifth stage, which is divided into the following steps: a detection step, wherein various detections before charging are carried out, and the next step is finished; step S71, initiating a charging request; step S72 starts charge transmission.

Preferably, the first connection is: the vehicle-mounted first communication module is connected with the management first communication module; the second connection is: the vehicle-mounted first communication module is connected with the ground first communication module of the target charging parking space; the third connection is: the connection between the auxiliary receiving coil of the vehicle and the ground positioning device is established; the first position is: satisfying a location for establishing the first connection; the second position is: a location for establishing the second connection is satisfied; the third position is: the location for establishing the third connection is satisfied.

Preferably, in the second stage and the third stage, there are also steps for verification, respectively, including: step S41, after step S22, the ground communication control unit will generate a unique identification code associated with the ground device; sending the identification code to the vehicle-mounted communication control unit through the second connection; and step S42, the vehicle-mounted communication control unit sends back the identification code to the ground communication control unit through the third connection so as to verify the consistency of the target charging parking space and the second connection.

Preferably, the unique identification code encodes each data bit in a manchester encoding mode, each encoded bit is divided into two equal intervals, and the corresponding waveform is adjusted at position 1/2 of the encoding period according to the value of the encoded data bit.

Preferably, the detecting step comprises: step S61, alignment detection; step S62, detecting a mutual inductance value; step S63, frequency detection and locking; step S64, foreign matter and living matter detection.

Preferably, at least the step S64 is continuously performed.

In this application, establish three connection through first three stage, accomplish and treat that the vehicle that charges is from looking for the charging parking stall to the whole flow that begins to charge, can high-efficient swift completion treat the matching between charging vehicle and the charging parking stall.

Drawings

FIG. 1 is a schematic structural diagram required for implementing the wireless charging method for an electric vehicle;

FIG. 2 is a schematic diagram of an exemplary embodiment of a wireless charging method for an electric vehicle;

fig. 3 is a flow chart of the wireless charging method for the electric vehicle.

Reference numerals are as follows:

a power supply source 0; a charging management system 1; a ground coil 21; a ground power converter 22; a ground communication control unit 23; a terrestrial first communication module 231; a terrestrial second communication module 232; a terrestrial communication controller 233; a ground positioning device 24; an auxiliary receiving coil 25; a vehicle-mounted coil 31; the vehicle-mounted power conversion device 32; an in-vehicle communication control unit 33; an in-vehicle first communication module 331; an in-vehicle second communication module 332; the in-vehicle communication controller 333; a vehicle-mounted positioning device 34, an auxiliary transmitting coil 35, a load 36; and a vehicle control unit 37.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative only and should not be construed as limiting the invention.

The invention discloses a wireless charging method for an electric automobile, which is divided into five stages as shown in figure 3, wherein each stage comprises a plurality of steps, and the method comprises the following specific steps:

the first stage comprises the following steps: step S10, the vehicle to be charged reaches the first position; step S11, the vehicle to be charged and the charging management system 1 establish a first connection; step S12, compatibility pre-check is carried out, and the next step is carried out after the pre-check is successful; and step S13, selecting a charging parking space.

The second stage comprises the following steps: step S20, reaching the second position; step S21, recognizing the service set identifier of the target terrestrial communication control unit 23 broadcasting it; step S22, the vehicle to be charged and the target ground communication control unit 23 establish a second connection; step S23, checking compatibility finally, and entering the next step after checking successfully; step S24, the process proceeds to the guide alignment phase.

The third stage comprises the following steps: step S30, reaching a third position; step S31, establishing a third connection between the auxiliary transmitting coil 35 and the auxiliary receiving coil 25 of the vehicle to be charged; step S32, the guide alignment is completed.

The fourth stage comprises the following steps: and step S50, verifying whether the vehicle to be charged is successfully paired with the charging, entering the next stage if the pairing is successful, and returning to the first stage if the pairing is not successful.

The fifth stage comprises the following steps: a detection step, wherein various detections before charging are carried out, and the next step is finished; step S71, initiating a charging request; step S72 starts charge transmission.

For convenience of understanding, the structure of both sides of the transmitting terminal and the receiving terminal when implementing wireless charging and the implementation manner are described in detail below with reference to fig. 1. For convenience of understanding, the following takes wireless charging of an electric vehicle as an example.

According to the position of the structure setting, two parts of ground equipment and vehicle-mounted equipment are distinguished, wherein the transmitting end belongs to the ground equipment, and the receiving end belongs to the vehicle-mounted equipment.

The ground equipment includes: the charging management system 1 (WCCMS, wireless charging control management system for short), a ground coil 21 (also called a transmitting coil), a ground power conversion device 22, a ground Communication control unit 23 (CSU for short), a ground positioning device 24, and an auxiliary receiving coil 25. It should be noted that, in a wireless charging parking space, at least: the ground coil 21, the ground power conversion device 22, the ground communication control unit 23, the ground positioning device 24 and the auxiliary receiving coil 25. The charging management system 1 may be shared by a plurality of wireless charging slots, and the slots are managed and distributed by the charging management system 1. The charging management system 1 may be installed in a wireless charging slot, or may be installed in other locations, such as a central control room.

The vehicle-mounted device includes: an In-Vehicle coil 31 (also called a receiving coil), an In-Vehicle power conversion device 32, an In-Vehicle communication control Unit 33 (IVU), an In-Vehicle positioning device 34, an auxiliary transmitting coil 35, and a load 36. The vehicle has a vehicle control unit 37, and the vehicle control unit 37 may collectively control a plurality of components on the vehicle and may participate in the wireless charging operation, so that the vehicle control unit 37 may also be calculated as a part of the vehicle-mounted device.

The ground coil 21 is connected to the external power supply source 0 through a ground power converter 22. Besides the ground power converter 22, the power supply 0 and the ground coil 21 may also have other necessary components, where the necessary components refer to components required by the transmitting end when completing the wireless charging operation, including but not limited to a detection module and a communication module.

The vehicle-mounted coil 31 is connected to a load 36 of the electric vehicle through the vehicle-mounted power conversion device 32, and the load 36 may be a power battery pack. Similar to the transmitting end, the vehicle-mounted coil 31 and the load 36 may have other necessary components besides the vehicle-mounted power conversion device 32, that is, the components required by the receiving end when completing the wireless charging operation, including but not limited to the detection module and the communication module.

The vehicle-mounted communication control unit 33, the ground communication control unit 23, and the charging management system 1 each include at least one controller, and each include two communication modules. Specifically, the vehicle-mounted communication control unit 33 has a vehicle-mounted first communication module 331 and a vehicle-mounted second communication module 332, and a vehicle-mounted communication controller 333 for management; the ground communication control unit 23 has a ground first communication module 231 and a ground second communication module 232, and a ground communication controller 233 for management; the charging management system 1 has a management first communication module 11 and a management second communication module 12, and further includes a management system controller.

When the vehicle-mounted first communication module 331 and the management first communication module 11 need to work, the vehicle-mounted first communication module 331 and the management first communication module 11 can be in wireless communication (communication), and information can be exchanged between the first communication module and the management first communication module; similarly, the vehicle-mounted first communication module 331 and the ground-based first communication module 231 can be wirelessly communicated (communicated) with each other, and information can be exchanged between them.

The communication standards and protocols used between the on-board communication control unit 33 and the charging management system 1, and between the on-board communication control unit 33 and the ground communication control unit 23 may be one or more of Ultra Wideband (UWB), ZigBee, Wi-Fi, or any other suitable communication standard and protocol, preferably Wi-Fi, the physical layer of communication of which should comply with the IEEE Std 802.11 specification. For convenience of explanation, this patent will be described using Wi-Fi as an example.

The management second communication module 12 and the ground second communication module 232 may be connected by wire or wirelessly, and are used for exchanging information between the charging management system 1 and the ground communication control unit 23.

The vehicle-mounted second communication module 332 is connected with the vehicle controller 37 in a wired or wireless manner, generally in a wired connection manner, and is used for information interaction between the vehicle-mounted communication control unit 33 and the vehicle.

In combination with the above method and corresponding structure, a parking lot (or charging station) is taken as an example, and the charging management system has a plurality of charging slots and at least one charging management system 1. Referring to fig. 2 and 3, the vehicle to be charged enters the charging station, arrives at the first location (step S10 shown in fig. 3), and we refer to the location where the connection establishment of the in-vehicle first communication module 331 with the management first communication module 11 can be satisfied as the first location. Generally speaking, the first communication module 11 is fixed in the parking lot, so the first position is also a range, that is, when the vehicle to be charged enters the range, that is, arrives at the first position, at least the requirement of connecting the two is satisfied, or the vehicle-mounted communication control unit 33 (the vehicle-mounted first communication module 331) is in the range covered by the signal of the charging management system 1 (managing the first communication module 11).

In the first position, a communication connection, abbreviated as WI connection or first connection, is established between the in-vehicle communication control unit 33 and the charging management system 1 (step S11 shown in fig. 3). After establishing the WI connection, the vehicle-mounted communication control unit 33 interacts with the charging management system 1 for first charging information, where the first charging information packet at least includes: the charging demand information and the available charging parking space information. For a vehicle to be charged, a charging slot (hereinafter referred to as an available charging slot) for providing wireless charging for the vehicle to be charged can be acquired. It should be noted that the information that is referred to below as the information interacted through the WI connection or the first connection is referred to as first charging information, such as information used for compatibility detection.

The vehicle to be charged acquires an available charging slot and selects the charging slot (step S13 in fig. 3), the method of acquiring the available charging slot generally has three modes including reservation, allocation, or free selection. Charging stations typically employ one or a combination of three approaches.

The reservation mode refers to that a vehicle to be charged contacts the charging management system 1 or an operation management platform on a higher layer of the charging management system in advance to obtain a charging parking space compatible with the vehicle-mounted equipment, the charging management system 1 reserves the charging parking space, when the vehicle to be charged arrives at a charging station within the reservation time, the vehicle-mounted communication control unit 33 initiates registration to the charging management system 1 and confirms the arrival, and the charging management system 1 feeds back information such as the position and the state of the reserved charging parking space to the vehicle-mounted communication control unit 33.

When the vehicle to be charged does not reserve or the charging station does not provide a reservation mode, the vehicle-mounted communication control unit 33 and the charging management system 1 establish information interaction through WI connection to complete processes of registration authentication, compatibility detection and the like, wherein the registration authentication means that the vehicle-mounted communication control unit 33 initiates a registration request to the charging management system 1, and the charging management system 1 authorizes the access legitimacy of the vehicle-mounted communication control unit 33.

When the charging station adopts the "distribution" mode, the charging management system 1 designates an available charging slot for the vehicle to be charged after the compatibility check, and feeds back the position information of the assigned charging slot to the vehicle-mounted communication control unit 33, so that the electric vehicle drives to the designated charging slot according to the position information. The "allocation" method is more suitable for an electric vehicle equipped with an automatic driving or automatic parking system, and the driving system (automatic driving system) can directly operate the vehicle to drive to the charging parking space according to the charging parking space position information "allocated" by the charging management system 1.

The present application describes an embodiment in the form of "free selection", which means that a driver of a vehicle to be charged or an autonomous driving system selects a charging slot by itself. When the charging station adopts a freely selected mode, the charging management system 1 feeds back the available charging space information, and the feedback mode comprises two modes of state identification and/or data transmission.

When the state identification mode is adopted, the charging management system 1 identifies the available charging parking spaces in a visual or auditory distinguishing mode, for example, the charging management system 1 can control the indicator lamps to be lightened and twinkle to serve as the identification of the available charging parking spaces, or indicate the available charging parking spaces in the forms of indication boards, display screens and the like, so that the driver can freely select the charging parking spaces. The ground equipment model suitable for the charging station in the form is single, only one or a plurality of types of ground equipment models are provided, and the available charging parking spaces which can normally work and are not reserved can be indicated through the change of the colors or the flashing times of the indicator lamps.

The data transmission is to push the relevant content directly to the in-vehicle communication control unit 33. After the first connection is established again, the first charging information can adopt a data transmission mode. The charging management system 1 may be configured to transmit data representing available charging slots, such as slot numbers of the available charging slots represented by numbers, letters or a combination thereof, to the on-board communication control unit 33, and each charging slot is displayed with a distinct identifier, so that the driver can conveniently identify the available charging slots according to the slot number identifier. The feedback information transmitted by the data transmission may also include a position map of the charging slot or a real-time navigation map of the charging station, and the position map or the real-time navigation map of the charging slot is displayed on the center console or the mobile terminal such as the mobile phone, and the position map or the real-time navigation map of the charging slot is marked with the available charging slot and the number of the charging slot, so that the driver can freely select the available charging slot, that is, the charging slot is selected in step S13 in fig. 3.

Of course, before selecting a charging slot, it is necessary to detect the compatibility of the slot with the vehicle to be charged. Whichever of the above three approaches is adopted, compatibility detection is required because in some embodiments, the number of compatibility detections is more than one, and for the sake of illustration, the compatibility detection is referred to as compatibility pre-check (step S12 in fig. 3).

The compatibility detection or compatibility pre-detection refers to that the vehicle-mounted communication control unit 33 uploads product information of the vehicle-mounted device to the charging management system 1, the product information which needs to be uploaded by the vehicle-mounted communication control unit 33 includes output power level, output voltage and current range, ground clearance, working frequency, coil type, resonant network topology and the like, and the charging management system 1 queries an available charging parking space according to the uploaded information, namely according to the compatibility between the ground device and the vehicle-mounted device and the state of the ground device. After the above process is completed, the charging management system 1 feeds back the available charging slot information to the in-vehicle communication control unit 33. If necessary, other necessary information interaction such as confirmation of the payment method and the like may be performed between the charging management system 1 and the in-vehicle communication control unit 33.

When the driver determines that the target charging slot is good and operates the electric vehicle to approach the target charging slot, the vehicle-mounted communication control unit 33 reaches the second position (step S20 in fig. three), and the vehicle-mounted communication control unit 33 establishes a connection with the ground communication control unit 23 (hereinafter referred to as the target CSU) of the target charging slot, that is, the vehicle-mounted first communication module 331 and the ground first communication module 231 are in communication connection, hereinafter referred to as CI connection or second connection (step S22 in fig. 3). Interacting second charging information through the CI connection or the second connection, the second charging information at least comprising: and verification information of the charging parking space and the vehicle to be charged. Of course, the second charging information may also include other information, for example, the "matching verification information for the charging slot and the vehicle to be charged" mentioned below, as long as the information exchanged via the CI connection or the second connection is the second charging information.

The second position is that the vehicle-mounted communication control unit 33 enters the signal coverage range of the ground communication control unit 23, or that the vehicle-mounted first communication module 331 is in a connectable range with the ground first communication module 231. The second position is a range within which the distance requirements of the two connections can be met and the CI connection can be established.

The operation mode of the ground first communication module 231 of the ground communication control unit 23 is configured as an Access Point (AP), the vehicle first communication module 331 of the vehicle-mounted communication control unit 33 is configured as a terminal Station (STA), and the ground communication control unit 23 controlling the available charging space is in a discovery mode while the charging management system 1 transmits the feedback information to the vehicle-mounted communication control unit 33, and allows the vehicle-mounted communication control unit 33 to establish a wireless connection with the ground communication control unit 23 of the available charging space.

When the ground communication control unit 23 is in the discovery mode, taking Wi-Fi communication as an example, each ground communication control unit 23 broadcasts its Service Set Identifier (SSID) through its ground first communication module 231, and the wireless connection of the broadcast ground communication control unit 23 is available. When the driver arrives at the target charging slot, and there are a plurality of available charging slots adjacent to and near the charging slot, the SSIDs sent by the ground communication control units 23 of the plurality of charging slots may be generally found, and the SSID of the selected target ground communication control unit 23 needs to be identified from the SSIDs (step S21 in fig. 3) and associated with the SSID. Note that the transmission and reception of the SSID here is when the second connection has not been established, and therefore the content does not include the second charging information. Of course, if it is considered that the ground communication control unit 23 calculates to establish the second connection through its ground first communication module 231 as long as the interaction of information occurs, the SSID may also be regarded as the second charging information.

There are various ways to identify the SSID of the target ground communication control unit 23, and in one embodiment, the SSID of the ground communication control unit 23 is manually selected and configured with a preset encoding rule, and is configured in the ground first communication module 231 of each ground communication control unit 23. The SSID is divided into a plurality of sub-segments according to the SSID coding rule, wherein one sub-segment is associated with the parking space number of the charging parking space, for example, the SSID of the ground communication control unit 23 is divided into 2 sub-segments, wherein the former sub-segment is WPT- ", the latter sub-segment is the parking space number or a unique code associated with the parking space number, and the two sub-segments are combined to form the SSID. For example, if the parking space number of a certain charging parking space is B11, the SSID broadcasted by the ground communication control unit 23 is WPT-B11. Assuming that the space numbers of the charging spaces adjacent to B11 are B10 and B12, respectively, the SSIDs broadcast by these ground communication control units 23 are WPT-B10 and WPT-B12, respectively, and when the vehicle to be charged approaches and selects charging space B11, the driver selects ground communication control unit 23 having the SSID of WPT-B11 to access according to the space number identified by the charging space.

Specifically, the vehicle-mounted communication control unit 33 contacts the charging management system 1 through WI connection, queries an access password of the ground communication control unit 23 with the SSID of WPT-B11, sends an association request to the ground first communication module 231 of the ground communication control unit 23, returns an association response (at this time, the corresponding first communication module 231 is regarded as an AP) to the STA (that is, the vehicle-mounted first communication module 331) through the corresponding ground first communication module 231 for authentication, and further establishes CI connection between the vehicle-mounted communication control unit 33 and the ground communication control unit 23.

In the position map of the charging slot or the real-time navigation map of the charging station included in the feedback information transmitted by the data, the SSID of the ground communication control unit 23 of each charging slot may also be labeled at the same time, and after the driver selects the target charging slot, the driver may directly select the corresponding ground communication control unit 23 to access according to the labeled SSID.

In the embodiment, manual intervention operation exists in the process, so that the user experience of non-inductive charging in wireless charging cannot be brought into play, and the method is not suitable for application occasions needing automatic connection, such as automatic parking and the like. In another embodiment, the SSID identifying the target ground communication control unit 23 is implemented in an automatic manner. The charging station and/or the vehicle to be charged are equipped with means for identification, such as Radio Frequency Identification (RFID), optical identification, etc. For example, a barcode, a two-dimensional code, a radio frequency tag, or other machine-readable codes are set on the charging car space, and information installed on the ground equipment of the charging car space is also stored in the readable codes, or may be obtained by performing information interaction query with the charging management system 1. When the vehicle to be charged with the identification component drives to the second position, the readable codes can be found and sensed or scanned, the vehicle-mounted communication control unit 33 acquires the SSID of the charging parking space after identifying the readable codes, the SSID is associated with the target ground communication control unit 23, and the ground communication control unit 23 establishes CI connection with the vehicle-mounted communication control unit 33 after confirming the access validity of the vehicle-mounted communication control unit.

The above embodiment requires additional hardware to be configured in the charging parking space or the vehicle to be charged, and the system implementation also has certain complexity. In order to overcome the above problem, the present application proposes an embodiment, in which the vehicle-mounted communication control unit 33 is configured to have a function of detecting a Received Signal Strength (RSSI) value, the vehicle-mounted communication control unit 33 compares the RSSI values of the Received signals, and generally, the stronger the RSSI value is, the closer the distance is, the stronger the RSSI value of the ground communication control unit 23 of the target charging slot Received at the second position should be than that of the other ground communication control units 23, so that the vehicle-mounted communication control unit 33 preferentially selects the ground communication control unit 23 with the largest Received RSSI to access according to the maximum Signal Strength algorithm. Further, in order to avoid the situation that the second position may not be identified due to a small difference of the plurality of RSSI values, or the identification error may be caused due to a low intensity of the power transmitted by the target ground communication control unit 23, the vehicle-mounted communication control unit 33 is connected to the plurality of ground communication control units 23, respectively, the time difference of a signal transmitted from the ground communication control unit 23 to the vehicle-mounted communication control unit 33 or the time of a signal going to and from the vehicle-mounted communication control unit 33 and the ground communication control unit 23 is measured, the distance between the vehicle-mounted communication control unit 33 and the ground communication control unit 23 is calculated according to the communication rate (light speed), and the ground communication control unit 23 to be accessed is determined according to the calculated distance and the difference of the RSSI values. Generally, the Wi-Fi communication module has a conventional range of several hundred meters, and transmits a signal covering a lot of parking spaces, so in this embodiment, the first communication module 231 of the ground communication control unit 23 is configured to operate at the lowest allowable transmission power, and at this lowest transmission power, the signal can cover the entire charging parking space and can be received by the vehicle communication control unit 33 entering the charging parking space, i.e., the second position, so that the cross influence between the Wi-Fi communication modules can be minimized. In some embodiments, the transmitting antenna of the Wi-Fi communication module is configured to have directivity by the installation location and/or the antenna form, for example, the transmitting antenna is a directional antenna, the intensity of the electromagnetic wave emitted by the directional antenna is stronger when the directional antenna faces the entering location of the electric vehicle entering the charging parking space from the front, and the intensity of the electromagnetic wave emitted by the directional antenna is weaker in other directions or is zero. When a vehicle to be charged enters the charging parking space from the front, the received RSSI value of the charging parking space should be the largest, and the received RSSI values of other Wi-Fi should be zero or relatively small, and can be very easily distinguished. When the on-vehicle communication control unit 33 recognizes the ground communication control unit 23 of the target charging slot, the on-vehicle communication control unit 33 inquires of the charging management system 1 of the SSID and the password of the charging slot, and then the on-vehicle communication control unit 33 automatically establishes a CI connection with the ground communication control unit 23 of the target charging slot.

After the CI connection is established, in some embodiments, compatibility checking and authentication may need to be performed again at this stage, such as before boot alignment is performed, or after boot alignment is completed, and before charging is started. The compatibility check varies the detected content according to the stage, such as the compatibility check after establishing WI connection as a compatibility pre-check (step S12), and the compatibility check after establishing CI connection as a compatibility final check (step S23), generally speaking, the parameter items of the final check are more comprehensive than those of the compatibility pre-check. In some embodiments, compatibility check is not performed again after CI connection is established; in other embodiments, authentication and compatibility checks are not performed when establishing the WI connection, but are performed after establishing the CI connection. In fig. 3, as an example, a compatibility pre-check after establishing a WI connection and a compatibility final check after establishing a CI connection are shown.

After the compatibility is finally checked, the boot alignment phase is entered (step S24). When the electric automobile is charged wirelessly, the ground coil 21 and the vehicle-mounted coil 31 need to be aligned as much as possible, so that the coupling between the ground coil and the vehicle-mounted coil can meet the requirements of power transmission and system efficiency. In order to facilitate the driver or the automatic parking system of the vehicle to park correctly in the charging slot, the wireless charging system is generally configured with a positioning device having a guiding and aligning function. In particular the above-mentioned ground positioning device 24 and an auxiliary receiving coil 25 cooperating therewith, the auxiliary receiving coil 25 having one or more.

The vehicle-mounted positioning device 34 is correspondingly provided on the vehicle end, and the auxiliary transmitting coil 35 is connected with the vehicle-mounted positioning device, and the auxiliary transmitting coil can be one or more. The auxiliary transmitting coil 35 excites an electromagnetic wave or an electromagnetic field with a certain frequency, the auxiliary receiving coil 25 receives the electromagnetic wave or the electromagnetic field, and the relative position between the auxiliary transmitting coil 35 and the auxiliary receiving coil 25 is obtained by measuring parameters such as electromagnetic field intensity, magnetic vector, induced voltage or current of the received electromagnetic wave or the electromagnetic field, so that the relative position between the vehicle-mounted coil 31 and the ground coil 21 can be calculated (for example, chinese patent 2020106812766 describes how to calculate the relative position between the vehicle-mounted coil 31 and the ground coil 21, which is not described herein again). For convenience of description, the auxiliary transmitting coil 35 and the auxiliary receiving coil 25 will be collectively referred to as an auxiliary coil.

Of course in some embodiments the positions of the auxiliary transmitting coil 35 and the auxiliary receiving coil 25 may be interchanged, i.e. the auxiliary transmitting coil 35 is comprised in the ground based device and correspondingly the auxiliary receiving coil 25 is comprised in the vehicle based device. In a simple manner, it is possible to use the present invention to perform the above-mentioned auxiliary functions, in particular to emit electromagnetic waves or fields on the ground or on board the vehicle.

In some embodiments, it is also possible to use the ground coil 21 or the vehicle-mounted coil 31 as an auxiliary transmitting coil without providing a separate auxiliary transmitting coil.

In the drawings, it is exemplified that the auxiliary transmitting coil 35 is provided in the vehicle-mounted device, and the auxiliary receiving coil 25 is provided in the ground device. When the auxiliary receiving coil 25 induces or receives the electromagnetic wave or field of the auxiliary transmitting coil 35, the two auxiliary coils are also equivalent to establishing a wireless connection. Specifically, the vehicle to be charged reaches the third position (step S30) where the connection, hereinafter simply referred to as the CI sub-connection or the third connection, is established (step S31). Like the first and second positions described above, the third position may also be a range that ensures at least the distance requirement for the auxiliary receive coil 25 and the auxiliary transmit coil 35 to establish the CI auxiliary connection.

Interacting third charging information through a third connection, the third charging information comprising at least: and the charging parking space and the guide alignment information of the vehicle to be charged. Other information transmitted via the third connection is part of the third charging information, for example "matching verification information for the charging station and the vehicle to be charged".

The intensity of the electromagnetic field or electromagnetic wave emitted by the auxiliary transmitting coil 35 is restricted by the state or government to the electromagnetic transmitting limit, and the acting distance is limited by adopting the above positioning mode, generally, the acting distance is within 2m to 5m, so that the third position can be within the range of the charging parking space. In the guiding alignment stage, after the CI connection is established but the CI auxiliary connection is not established, namely between the second position and the third position, a sensor of an intelligent driving system of the vehicle to be charged can be used for conducting remote guiding.

In order to realize automatic driving or automatic and semi-automatic parking, modern automobiles are generally provided with sensors such as millimeter wave radar, laser radar, ultrasonic radar, panoramic camera and the like, the sensors can act at a longer distance and generally have relatively higher precision, and the functions of the sensors can be integrated in a guiding and aligning stage, so that long-distance guiding is completed by taking a ground coil 21 as a target. In some embodiments, the second location is reached not by a sensor supporting remote guidance, but by an optical camera, an aid line, or visual judgment of the driver. The above-mentioned remote guidance is done before the establishment of the CI auxiliary connection, and the guidance alignment mentioned in this application by default includes a remote guidance procedure, and its specific implementation belongs to the prior art and is not cited in this patent. Briefly, the guiding alignment includes a long-distance guiding and a fine guiding, and the long-distance guiding does not necessarily depend on the CI auxiliary connection to be completed, and the position can be directly judged by the driver. The CI secondary connection is established to accomplish the fine-grained bootstrap.

In the guiding alignment phase, the vehicle-mounted communication control unit 33 and the ground communication control unit 23 exchange position information through the CI connection, so that a driver or a parking system can operate the vehicle to be aligned correctly, and after the guiding alignment phase is completed, whether the electric vehicle is parked in a correct charging slot and whether the CI connection is correct are verified.

In any of the free, allocation, and reservation modes, there is a possibility that a CI connection error occurs due to a failure in recognition, that is, the in-vehicle communication control unit 33 is erroneously connected to a Wi-Fi module of a charging slot other than the target charging slot, so that the charging slot where the electric vehicle is parked and the charging slot where the CI connection is performed do not coincide. If the ground positioning device 24 and/or the vehicle positioning device 34 fail, for example, a plurality of electric vehicles are in the guiding alignment phase at the same time, the signals received by the ground positioning device are interfered, for example, the charging slot connected to the CI receives electromagnetic fields or electromagnetic waves emitted by the vehicle positioning devices of other electric vehicles, and the vehicle communication control unit 33 parked at the target charging slot is fed back through the CI connection to complete the guiding alignment (step S32).

At this time, the vehicle-mounted communication control unit 33 requests the charging slot connected to the CI (i.e., the charging slot in which the ground first communication module 231 connected to the vehicle-mounted first communication module 331 and the CI is located) to transmit high power to the ground device for wireless transmission, which may cause a danger that unintended power transmission may be caused. In extreme cases, there is a greater potential safety risk caused by the absence of an electric vehicle in the CI-connected charging slot, or the parking of another vehicle, even a fuel-powered vehicle, or the presence of human activity in the charging slot.

To avoid the above-mentioned problems, and the problem of unexpected power delivery, the on-board communication control unit 33 and the ground communication control unit 23 in the charging slot are subjected to matching verification by a unique identification code (hereinafter abbreviated as ID) at the third connection location via the CI auxiliary connection to confirm that the vehicle to be charged is parked in the correct parking slot. As an example, the matching verification process will be described below.

First, after the CI connection is established, the ground communication control unit 23 will generate a unique ID associated with the ground device; second, the ground communication control unit 23 transmits an ID to the in-vehicle communication control unit 33 through the CI connection (step S41). The ID is converted into binary data and further into a sequence of coded bits according to the coding pattern. When the vehicle to be charged arrives at the third position and the vehicle to be charged is parked at the charging slot, the third step is performed, and the in-vehicle communication control unit 33 returns the ID to the ground communication control unit 23 by establishing the CI auxiliary connection (step S42) to verify the consistency of the target charging slot and the CI connection.

It should be noted that steps S41 and S42 are continued after steps S22 and S32, and they are used for matching verification, so that there is a difference in need. In practical applications, the above processes may be performed sequentially, or the sequence of matching verification may be skipped. That is, steps S41 and S42 are not necessarily performed in the above-described sequence, and the matching verification may be performed before the final charging.

In the present specification, the second connection and the third connection are used to complete the work (i.e., the above steps S41 and S42), that is, the above-mentioned "matching verification information for the charging slot and the vehicle to be charged".

The specific mode of the loopback verification is as follows: the onboard positioning device 34 loads the coded bit sequence of the ID onto the varying waveform of the electromagnetic wave or field emitted by the auxiliary transmitting coil 35 by modulation, i.e., the varying waveform of the electromagnetic wave or field excited by the auxiliary transmitting coil 35 varies according to the coded bit sequence of the ID. Preferably, the encoding mode uses manchester encoding. Coding each data bit according to the Manchester coding mode, wherein each coded bit is divided into two equal intervals, and if the coded data bit is '1' at 1/2 bits of the coding period, the waveform is changed from high peak value to negative jump to low peak value; conversely, if the encoded data bit is "0," the waveform transitions from a low peak to a high peak. The auxiliary receiving coil 25 receives the electromagnetic wave or field from the auxiliary transmitting coil 35, the ground communication control unit 23 decodes the coded bit sequence according to the coding mode to convert it into ID, and compares it with the ID in the first step.

Next, the process proceeds to step S50, where whether the matching verification is successful or not is determined by comparing the verification result, and if the received IDs match, the matching verification is successful, the ground communication control unit 23 feeds back the information of the successful matching verification to the vehicle communication control unit 33 through the CI connection, and may perform subsequent processes, such as alignment detection (step S61), mutual inductance value detection (step S62), frequency detection and locking (step S63), foreign object detection (step S64), and the like, which may be collectively referred to as a detection step.

If the received IDs do not match, or if the auxiliary receiving coil 25 cannot receive the electromagnetic wave or the electromagnetic field emitted from the auxiliary transmitting coil 35 after a plurality of attempts, it is determined that the matching verification has failed, and the ground communication control unit 23 feeds back information of the matching verification failure to the vehicle communication control unit 33. And may return to before the second connection, for example, to step S13 to select a charging slot, and the second connection may be newly made.

The match verification process is performed after the CI secondary connection is established, in some embodiments, the match verification process is performed only once, and the match verification process may occur after the CI connection is established or after the boot alignment phase is completed. The execution of only once as described herein does not mean that the matching authentication ID is transmitted only once, but means that the ID is not transmitted after the matching authentication is successful.

In other embodiments, the matching verification process is continuously performed after the CI auxiliary connection is established, at this time, the electromagnetic wave and the electromagnetic field for positioning excited by the auxiliary transmitting coil 35 continuously change according to the coding bit sequence, and the ID matching verification codes are always compared during the guiding alignment process, so as to ensure that the vehicle-mounted communication control unit 33 and the target ground communication control unit 23 are always in the correct connection state during the guiding alignment process.

After the start of the guidance alignment, the vehicle-mounted communication control unit 33 obtains the position information of the ground coil 21 through the CI connection request, and in the guidance alignment process, the position information between the vehicle to be charged and the ground coil 21 is interacted through the CI connection, and the driver or the parking system operates the vehicle in the charging parking space, so that the position of the vehicle after the vehicle to be charged is parked is within the allowable offset range defined by the wireless charging system.

After the pilot alignment and matching verification process is completed, the wireless charging system performs coil alignment detection (step S61) to confirm that the positional deviation between the ground coil 21 and the on-vehicle coil 31 is within the alignment tolerance zone before starting charging, and generally, the alignment detection is also performed by the ground positioning device 24 and the on-vehicle positioning device 34. Further, in some embodiments, before the charging is started, a mutual inductance value detection (step S62) that meets the requirement of power transmission by detecting the mutual inductance value between the ground coil 21 and the vehicle-mounted coil 31 and a frequency detection and locking (step S63) process are generally included, where the frequency detection and locking is performed by detecting the operating frequency of the ground device by the vehicle-mounted device, and the vehicle-mounted device can make the operating frequency of the vehicle-mounted device consistent with the detected operating frequency within an error allowable range. The above process can further ensure that the ground coil 21 and the vehicle-mounted coil 31 are in an aligned state and in an operable state, and before the charging is started, the process generally comprises a foreign object and living object detection process, wherein the foreign object detection process is used for detecting whether a metal object entering abnormally exists in a transmission space between the ground coil and the vehicle-mounted coil, so that the condition that the metal foreign object is heated by an electromagnetic field of wireless charging is prevented. The living body detection means detecting whether an abnormal living body enters a transmission space between a ground coil and a vehicle-mounted coil, and preventing possible damage to the living body caused by an electromagnetic field of wireless charging.

In the process, when the charging parking space needs to be changed before charging, or the conditions of matching verification, failed compatibility check and the like occur, the CI connection can be disconnected, and the charging parking space is reselected; if the matching of the charging parking spaces cannot be completed all the time, the charging stations can be contacted for fault treatment.

When the above-described process is completed, the in-vehicle communication control unit 33 may initiate a charging request to the ground communication control unit 23 through the CI connection (step S71), and enter the charging transmission phase (step S72). After the charging transmission stage begins, the power supply outputs power frequency alternating current, the alternating current is converted into high-frequency alternating current through the ground power conversion device and then is loaded on the ground coil, electric energy is converted into a magnetic field, the magnetic field can be propagated through air, after the vehicle-mounted coil is coupled to the magnetic field, current is generated in the vehicle-mounted coil due to electromagnetic induction, the current is converted into direct current through the vehicle-mounted power conversion device to charge the automobile power battery, and therefore wireless transmission of the electric energy from the power supply to the power battery is achieved.

In the charging transmission stage process, the CI connection is also used as a channel for interactive communication between the wireless charging vehicle-mounted device and the ground device, and information interaction such as charging requirements, control data, abnormal alarm and the like is carried out. In some embodiments, the CI auxiliary connection continues to maintain the connection during the charging transmission phase, and repeats the matching verification process as a keep-alive signal for the operating state of the wireless charging system; in some embodiments, the auxiliary transmitting coil continuously excites the electromagnetic wave and the electromagnetic field for positioning, and the ground communication control unit 23 detects whether the electric vehicle has abnormal movement during charging.

Besides the scheme, the scheme that the CI auxiliary connection is established first and then the CI connection is established is further provided, and the scheme is suitable for the situation that all charging parking spaces and the vehicles to be charged can be completely matched and positioning guidance is not needed. In this embodiment, when a vehicle to be charged, which carries the auxiliary transmitting coil 35, enters the charging space, the electromagnetic wave or the electromagnetic field emitted by the auxiliary transmitting coil 35 is loaded with specific information in the form of the aforementioned code, and the specific information may be information of the on-vehicle communication control unit 33 registered in the charging management system 1 in advance.

The auxiliary receiving coil 25 inductively receives the electromagnetic wave or electromagnetic field excited by the auxiliary transmitting coil 35, that is, when CI auxiliary connection is established, the ground communication control unit 23 recognizes that the vehicle to be charged enters the charging slot and enters the third connection position, the ground communication control unit 23 starts to broadcast that connection is available, the ground communication control unit 23 decodes the specific information loaded on the received electromagnetic wave or electromagnetic field, and then sends the recognized specific information (access information including SSID and password in addition to the information of the vehicle-mounted communication control unit 33) to the vehicle-mounted communication control unit 33, and the vehicle-mounted communication control unit 33 initiates association with the ground communication control unit 23 to establish CI connection, and the position is also used as the second connection position. Generally, the range covered by the third connection position is smaller than the range covered by the second connection position, and in this embodiment, the third connection position and the second connection position are coincident, and this embodiment is suitable for a scene that does not need remote guidance or does not need CI connection during remote guidance.

The functional safety will be explained below. In the wireless charging space determining process, safety risks are involved if the unexpected power transmission occurs. In order to ensure that unacceptable systematic and random hardware failure risks are avoided in the automotive field, functional safety development procedures and requirements of feasibility according to the functional safety standard ISO 262262 are proposed, according to which functional safety risk levels are pre-evaluated to determine the automotive safety integrity level of the system, then a safety objective is assigned to each risk, and a risk-reducing mechanism is pre-implanted into the system as part of the system's functions.

The ISO 262262 standard proposes the concept of automotive integrity class (ASIL), which is an important index for evaluating the safety of automotive electronic functions. ASIL is divided into 4 grades from a to D, with D being the highest grade and a being the lowest grade. The higher the ASIL corresponds to, the higher the requirements on system functional safety. The ASIL grade is determined according to the probability of occurrence of each hazard event, the severity degree after occurrence and the controllability of a driver, and the result is obtained according to a specific calculation rule.

For example, for wireless charging of an electric vehicle, unexpected power transmission during charging is a dangerous event, and in particular, may be decomposed into various functional failures and failure effects, such as unexpected power transmission during a non-target charging vehicle parking situation, which may cause the vehicle chassis to be heated; the occurrence of unintended power transfer in the event of human activity can result in a risk to human health. Accordingly, the ASIL levels corresponding to the different functional safety objectives are determined by systematically evaluating the hazard event itself, e.g., for a functional safety objective to avoid unintended power delivery in the presence of a vehicle, the ASIL levels will be determined B; the functional safety objective is to avoid unintended power transfer when there is no vehicle, the ASIL level will be determined D, and the wireless charging system will require satisfaction of the highest functional safety level ASIL D thereof.

The functional safety of the wireless charging system is mainly determined in the product design and development stages, and the ISO 26262 evaluates the hardware functional safety design of the system through hardware architecture indexes, and respectively performs failure analysis and calculation on each circuit module related to the functional safety in the device. In the specific calculation, the failure mode and failure influence of each component are analyzed, the hardware architecture index in the equipment is calculated through a calculation formula provided in the standard, and whether the function safety level defined in the safety target is met or not is judged.

Among failure modes causing functional safety risks, systematic failure refers to the fact that behaviors in an artificial design or manufacturing process influence safety-related factors, so that products are subjected to unexpected failure, and the failure mode can determine the reason and eliminate the reason by modifying the design; the random failure of hardware refers to failure caused by random failure of one or more components in a system, is usually difficult to predict and eliminate, and is a main source of functional safety risk. In order to enable the wireless charging system to meet the preset ASIL level of functional safety, the random failure risk of hardware is reduced.

In the present application, as a safety mechanism of a hardware architecture, at least one of the components related to the charging function safety objective in the ground communication control unit 23 and the vehicle communication control unit 33 is provided with a redundant component. For convenience of explanation, components related to the charging function safety target will be referred to as original components hereinafter.

When the system is in operation, the original component and the redundant component are in working states at the same time, and through configuration, the ground communication control unit 23 and the vehicle-mounted communication control unit 33 have hardware architecture indexes required by the highest functional safety level defined by the charging safety target.

Taking the hardware architecture of the ground communication control unit 23 as an example, the ground communication control unit 23 includes a ground communication controller 233, a ground first communication module 231, and a ground second communication module 232, and generally includes a power management module, a signal input and processing module, a safety-related circuit module, and the like. Wherein the ground communication controller 233 is configured to include: the monitoring system comprises two control cores and a monitoring core, wherein the two control cores are divided into a main core and an auxiliary core, the two control cores run the same program during running, the result is input into the monitoring core, the monitoring core periodically compares the output results of the two cores, the running deviation is detected, and the monitoring core is responsible for decision making and execution. If the two are the same, continuing to operate; otherwise, certain measures need to be taken. If an error is present after a period of time, the system may restart or recheck. Similarly, the in-vehicle communication controller 333 also has a corresponding configuration.

Specifically, when the output results are consistent, the monitoring core generates an interrupt, and the current states of the two control cores are saved to the memory in the form of a checkpoint file. And under the condition that the output results are inconsistent, the monitoring core generates an interrupt, and the two control cores call the latest saved check point file to implement rollback so as to restore the system.

With the above configuration, in selecting and matching the charging slot to start charging, many steps are associated with the possibility that unintended power transmission may occur, including control of guiding the alignment process, alignment detection, generation of ID, transmission of ID by the ground communication control unit 23 to the vehicle communication control unit 33, return of ID by the vehicle communication control unit 33 to the ground communication control unit 23, and the like, which are performed by the ground communication control unit 23 and the vehicle communication control unit 33 satisfying the level corresponding to the functional safety target, and the safety of wireless charging can be further ensured.

In the above embodiments, the redundant control core is integrated into one controller, and in some embodiments, the ground communication control unit 23 has two independent controllers, one of which serves as a main controller, and the other serves as an auxiliary controller, and the auxiliary controller continuously monitors the operation of the main controller, and when the main controller is not operated normally or there is a hardware failure in the main control module, the auxiliary controller replaces the main controller to operate, so as to keep the most basic functions to continue to operate.

In the hardware architecture of the ground communication control unit 23, except for the controller, other components such as a power module, a clock module, a communication module, and the like have a probability of hardware failure, and the corresponding components can also make the ground communication control unit 23 further reduce the random failure rate of the hardware through redundancy setting, so that the hardware architecture index of the ground communication control unit 23 can meet the highest ASIL level defined by the functional safety objective as a whole.

The parking lot and the charging station mentioned in the specification refer to places with a plurality of wireless charging parking spaces, and the scheme recorded in the specification can help the vehicle to be charged to select a proper charging parking space from the parking lot and the charging station for wireless charging.

Based on the three connections established by the method, the matching process can be completed more efficiently. For parking lots and charging stations, the traffic flow is high, if only single communication is relied on, for example, only the connection between the vehicle to be charged and the charging management system 1 is established, and information interacted by all charging processes is based on the connection, extremely high load is inevitably brought to the charging management system 1, and once a fault occurs, all wireless charging work is influenced. In this application, through three connection, with the communication split of whole wireless flow of charging, reduce system load. Particularly, after the second connection is established, the charging management system 1 may disconnect from the corresponding vehicle to be charged or place the two in a low data interaction state, so as to reduce the load.

The vehicle to be charged is allowed to interact with the ground communication control unit 23 and the ground positioning device 24 on the charging parking space respectively, different information is processed, namely, the information is not interfered with each other, the processing speed is increased, and the safety requirement of interaction of all parts can be met. Meanwhile, the second connection and the third connection have the function of interacting the unique identification codes, so that the problem of unexpected power transmission is solved, the safe wireless charging is ensured, and further, the corresponding relation between the vehicle to be charged and the charging parking space is verified.

In conclusion, the three connections bear functions, namely, the three connections have independent parts and parts depending on each other, and compared with a single communication scheme in the prior art, the communication scheme has the advantages of higher efficiency and better safety performance.

The construction, features and functions of the present invention are described in detail in the embodiments illustrated in the drawings, which are only preferred embodiments of the present invention, but the present invention is not limited by the drawings, and all equivalent embodiments modified or changed according to the idea of the present invention should fall within the protection scope of the present invention without departing from the spirit of the present invention covered by the description and the drawings.

Claims

1. A wireless charging method for an electric vehicle is characterized by comprising the following steps:

a first stage, which is divided into the following steps: step S10, the vehicle to be charged reaches the first position; step S11, the vehicle to be charged and the charging management system (1) establish a first connection; step S12, compatibility pre-check is carried out, and the next step is carried out after the pre-check is successful; step S13, selecting a charging parking space;

and the second stage comprises the following steps: step S20, reaching the second position; step S21, identifying the service set identity of the target terrestrial communication control unit (23) broadcasting it; step S22, the vehicle to be charged and the target ground communication control unit (23) establish a second connection; step S23, checking compatibility finally, and entering the next step after checking successfully; step S24, entering a guiding alignment stage;

a third stage, which is divided into the following steps: step S30, reaching a third position; step S31, establishing a third connection between an auxiliary transmitting coil (35) and an auxiliary receiving coil (25) of the vehicle to be charged; step S32, completing guide alignment;

a fourth stage, which is divided into the following steps: step S50, verifying whether the vehicle to be charged is successfully paired with the charging, entering the next stage if the pairing is successful, and returning to the first stage if the pairing is not successful;

a fifth stage, which is divided into the following steps: a detection step, wherein various detections before charging are carried out, and the next step is finished; step S71, initiating a charging request; step S72 starts charge transmission.

2. The wireless charging method for electric vehicles according to claim 1,

the first connection is: the connection established by the vehicle-mounted first communication module (331) and the management first communication module (11);

the second connection is: the vehicle-mounted first communication module (331) is connected with the ground first communication module (231) of the target charging parking space;

the third connection is: -a connection established between an auxiliary receiving coil (25) of the vehicle and a ground positioning device (24);

the first position is: satisfying a location for establishing the first connection;

the second position is: satisfying a location for establishing a second connection;

the third position is: the location for establishing the third connection is satisfied.

3. The wireless charging method for electric vehicles according to claim 1,

in the second stage and the third stage, there are also steps for verification, respectively, including:

step S41, after step S22, the ground communication control unit (23) will generate a unique identification code associated with the ground equipment; -sending the identification code to the vehicle communication control unit (33) via the second connection;

in step S42, the vehicle-mounted communication control unit (33) returns an identification code to the ground communication control unit (23) through the third connection to verify the consistency of the target charging slot and the second connection.

4. The wireless charging method for electric vehicles according to claim 3,

the unique identification code encodes each data bit in a manchester encoding mode, each encoded bit is divided into two equal intervals, and the corresponding waveform is adjusted at position 1/2 of the encoding period according to the value of the encoded data bit.

5. The wireless charging method for electric vehicles according to claim 1,

the detecting step comprises: step S61, alignment detection; step S62, detecting the mutual inductance value; step S63, frequency detection and locking; step S64, foreign matter and living matter detection.

6. The wireless charging method for electric vehicles according to claim 5,

at least the step S64 continues.