EV-WPT system based on receiving side topology switching for identity recognition

Abstract

The present invention relates to the technical field of electric vehicle wireless power transmission (EV-WPT), and specifically discloses an EV-WPT system for identity recognition based on receiving side topology switching, including an electric energy transmitting end and an electric energy receiving end, wherein the electric energy receiving end is provided with a secondary side compensation network with a convertible topology; the EV-WPT system also includes a primary side controller, a secondary side controller, and a current detection circuit; the secondary side compensation network switches between a first secondary side compensation network and a second secondary side compensation network under the control of the secondary side controller. The identity recognition of the electric vehicle is completed by analyzing the primary side output current before and after the secondary side compensation topology switching, and when the identity recognition is passed, a communication connection between the primary and secondary sides is established, and the electric vehicle is started to be charged normally, thereby avoiding charging of an electric vehicle that does not match the electric energy transmitting end, and ensuring charging safety.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle wireless power transmission (EV-WPT), and in particular to an EV-WPT system for performing identity recognition based on receiving side topology switching. Background Art

[0002] Wireless charging technology has the advantages of reliability, safety, and convenience. It is increasingly used in the fields of medical, military, electronic portable devices, and electric vehicles. In order to achieve optimal system energy efficiency and status monitoring, and improve the performance of the wireless charging system, the wireless charging system for electric vehicles often requires communication interaction information between the primary and secondary sides. At the same time, for the wireless charging system for electric vehicles, in order to ensure the safe operation of the charging process, it is also necessary to ensure that the receiving end and the transmitting end can match before wireless charging. Only after the match is successful can the communication connection and subsequent charging be opened to avoid charging some electric vehicles that do not match the transmitting end (for example, they do not meet the production specifications, the charging circuit has been modified, the charging circuit has been damaged, the charging circuit is greatly interfered and its characteristics have changed greatly, etc.), which may bring some safety hazards. Summary of the invention

[0003] The present invention provides an EV-WPT system for identity recognition based on receiving side topology switching, and solves the technical problem of how to identify the receiving end (electric vehicle) to avoid charging the electric vehicle that does not match the power transmitting end, thereby ensuring charging safety.

[0004] In order to solve the above technical problems, the present invention provides an EV-WPT system for identity recognition based on receiving side topology switching, including an electric energy transmitting end located on the primary side and an electric energy receiving end located on the secondary side, and the electric energy receiving end is provided with a secondary side compensation network; the key is that the EV-WPT system also includes a primary side controller and a current detection circuit located on the primary side, and a secondary side controller located on the secondary side; the secondary side compensation network switches between a first secondary side compensation network and a second secondary side compensation network under the control of the secondary side controller;

[0005] When the electric vehicle enters a parking space, the secondary side controller sends a connection request signal to the primary side controller, and at this time, the secondary side controller also controls the secondary side compensation network to be the first secondary side compensation network; after receiving the connection request signal, the primary side controller controls the power transmitting end to operate at low power, and controls the current detection circuit to collect the first primary side current;

[0006] After receiving the first primary current, the primary controller sends a secondary topology switching signal to the secondary controller; after receiving the secondary topology switching signal, the secondary controller controls the secondary compensation network to switch to the second secondary compensation network;

[0007] The primary side controller controls the current detection circuit to collect the second primary side current after sending the secondary side topology switching signal for a preset time period; the primary side controller identifies the identity information of the electric vehicle according to the first primary side current and the second primary side current, and determines whether to establish a communication connection with the electric vehicle according to the identity information, and if so, sends a connection confirmation signal to the secondary side controller;

[0008] After receiving the connection confirmation signal, the secondary side controller sends a charging request to the primary side controller, and the primary side controller controls the operation of the power transmitting end according to the charging request.

[0009] As a preferred embodiment, the secondary compensation network includes a first secondary coil L s , the second secondary coil L f2 、The first secondary capacitor C s , the second secondary capacitor C f2 and switch S, first secondary coil L s , the second secondary coil L f2 、The first secondary capacitor C s 、The first secondary capacitor C f2 The connection relationship with switch S is:

[0010] When the switch S is turned off, the second secondary coil L f2 With the second secondary capacitor C f2 Connected in series, forming an S-type compensation topology, where the second secondary coil L f2 As a secondary receiving coil;

[0011] When the switch S is closed, the first secondary coil L s As the secondary receiving coil, the second secondary coil L f2 、The first secondary capacitor C s , the second secondary capacitor C f2 The LCC compensation topology is formed, where the first secondary capacitor C s is the secondary side series compensation capacitor, the second secondary side capacitor C f2 is the parallel compensation capacitor.

[0012] As a preferred implementation, the primary side controller determines whether to establish a communication connection with the electric vehicle according to the identity information, specifically:

[0013] D1, determine whether there is a specific car model in the identity information, if yes, go to step D2, if not, go to step D3;

[0014] D2, judging whether the electric vehicle is a vehicle model supported by the EV-WPT system according to the vehicle model, and if so, sending a connection confirmation signal to the secondary side controller, and if not, executing step D3;

[0015] D3. Send a connection rejection signal to the secondary side controller, and control the power transmitting end to stop power transmission.

[0016] As a preferred implementation manner, the primary controller identifies the identity information of the electric vehicle according to the first primary current and the second primary current, specifically comprising the steps of:

[0017] S1, the primary side controller extracts multiple types of features of the first primary current and the second primary current to obtain a feature combination;

[0018] S2. Perform feature matching on the feature combination in a preset feature combination pool. If a consistent feature combination can be found, the vehicle model information corresponding to the consistent feature combination is used as the identity information of the electric vehicle.

[0019] As a preferred implementation, in step S1, the extracted multiple features include amplitude, phase, and frequency, and the obtained feature combination includes the amplitude of the first primary current. A 1. Phase φ 1. Frequency f 1 and the amplitude of the second primary current A 2. Phase φ 2. Frequency f 2.

[0020] As a preferred embodiment, the EV-WPT system also includes a primary side communication module arranged on the primary side and a secondary side communication module arranged on the secondary side, and the primary side controller and the secondary side controller exchange information through a wireless communication link formed by the primary side communication module and the secondary side communication module.

[0021] As a preferred implementation, the primary side communication module and the secondary side communication module adopt WiFi modules.

[0022] As a preferred embodiment, the electric energy transmitting end is provided with a primary compensation network, and the primary compensation network includes an LCC type compensation network and a transmitting coil. L p The current detection circuit includes a connected current transformer CT and a measuring instrument and a protection circuit connected to the secondary side of the current transformer.

[0023] The EV-WPT system for identity recognition based on receiving side topology switching provided by the present invention, when the electric vehicle enters the charging area, the secondary side controller sends a charging application to the primary side controller. After receiving the application signal, the primary side controller first uses a smaller power signal to identify the electric vehicle through the wireless charging system. In this process, the identity of the electric vehicle is identified by analyzing the primary side output current before and after the secondary side compensation topology switching. When the identity recognition is passed, the communication connection between the primary and secondary sides is established, and the electric vehicle is charged normally, thereby avoiding charging of electric vehicles that do not match the power transmitter, and ensuring charging safety.

[0024] The present invention is based on the method of topology switching. By switching the secondary compensation topology structure, different primary current combinations can be obtained, and the primary current combination is matched with the preset primary current combination. Only when they match can the primary and secondary communication connection be established and charging is started. It has the advantages of high accuracy and simple detection. And the secondary compensation topology can also be applied in formal charging. In the fully resonant state, the LCC-S type topology can realize constant voltage charging, and the LCC-LCC type topology can realize constant current charging. Based on this, the system can select different charging schemes based on different situations. In addition, the present invention makes full use of the power transmission system for charging electric vehicles for identity recognition, without introducing other detection equipment, simple structure, and cost saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a circuit topology diagram of an EV-WPT system for identity identification based on receiving side topology switching provided by an embodiment of the present invention;

[0026] Figure 2 It is a flow chart of identity identification based on receiving side topology switching provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The following specifically illustrates the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and cannot be understood as limiting the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0028] The embodiment of the present invention provides an EV-WPT system for identity recognition based on receiving side topology switching, such as Figure 1As shown, it includes an electric energy transmitting end located on the primary side and an electric energy receiving end located on the secondary side. The electric energy transmitting end includes a DC power supply, a high-frequency inverter, and a primary compensation network connected in sequence, and the electric energy receiving end includes a secondary compensation network, a secondary rectifier filter circuit, and a load connected in sequence. The EV-WPT system provided by an embodiment of the present invention also includes a primary controller and a current detection circuit located on the primary side, and a secondary controller located on the secondary side. When the electric vehicle enters the parking space, the secondary controller sends a connection request signal to the primary controller, and at this time the secondary controller also controls the secondary compensation network to be the first secondary compensation network; after receiving the connection request signal, the primary controller controls the electric energy transmitting end to operate at low power, and controls the current detection circuit to collect the first primary current.

[0029] After receiving the first primary current, the primary controller sends a secondary topology switching signal to the secondary controller; after receiving the secondary topology switching signal, the secondary controller controls the secondary compensation network to switch to the second secondary compensation network;

[0030] The primary side controller controls the current detection circuit to collect the second primary side current after sending the secondary side topology switching signal for a preset time period; the primary side controller identifies the identity information of the electric vehicle according to the first primary side current and the second primary side current, and determines whether to establish a communication connection with the electric vehicle according to the identity information, and if so, sends a connection confirmation signal to the secondary side controller;

[0031] After receiving the connection confirmation signal, the secondary side controller sends a charging request to the primary side controller, and the primary side controller controls the operation of the power transmitting end according to the charging request.

[0032] The secondary side compensation network can switch between the LCC compensation topology and the S-type compensation topology using only one switch, which is simple to control and low in cost.

[0033] The current detection circuit includes a connected current transformer CT and a measuring instrument and a protection circuit connected to the secondary side of the current transformer. The current transformer CT is used to proportionally reduce the primary current to the secondary side of the current transformer, the measuring instrument and the measuring instrument in the protection circuit are used to measure the current parameters of the secondary side of the current transformer, and the protection circuit is used to prevent the secondary side of the current transformer from being open circuited and causing damage to the equipment.

[0034] The secondary compensation network switches between the first secondary compensation network and the second secondary compensation network under the control of the secondary controller. The secondary compensation network includes a first secondary coil L s , the second secondary coil L f2 、The first secondary capacitor C s , the second secondary capacitor C f2 and switch S, first secondary coil L s , the second secondary coil L f2 、The first secondary capacitor Cs 、The first secondary capacitor C f2 The connection relationship with switch S is:

[0035] When the switch S is turned off, the second secondary coil L f2 With the second secondary capacitor C f2 Connected in series, forming an S-type compensation topology, where the second secondary coil L f2 As a secondary receiving coil;

[0036] When the switch S is closed, the first secondary coil L s As the secondary receiving coil, the second secondary coil L f2 、The first secondary capacitor C s , the second secondary capacitor C f2 The LCC compensation topology is formed, where the first secondary capacitor C s is the secondary side series compensation capacitor, the second secondary side capacitor C f2 is the parallel compensation capacitor.

[0037] Figure 1 A circuit topology diagram of an EV-WPT system provided in an embodiment of the present invention, Figure 1 DC is the DC power input, MOSFET Q1~Q4 form a full-bridge inverter circuit, L f1 , C f1 , C P and L P The primary compensation network is composed of C S , L S , C f2 , L f2 Together they form a secondary side compensation network. When switch S is closed, the system forms an LCC-LCC topology, where L P and L S They are the primary coil and the secondary coil respectively, M1 is L P The mutual inductance between Ls and Ls; when the switch is turned off, the system forms an LCC-S topology, L P and L f2 They are the primary coil and the secondary coil respectively, M2 is L P With L f2 The mutual inductance between them. Diodes D1~D4 form a rectifier circuit, C d is the filter capacitor, BAT represents the battery load of the electric vehicle, R d Indicates its internal resistance.

[0038] When the load is different, the secondary current will change under the same topology, causing the primary current to change as well. The present invention identifies the electric vehicle by detecting the primary current under different topologies. When the topology changes, the current on the primary side will also be different for the same load connected to the wireless charging system. In this way, after the various parameters of the current value of the same load before and after the topology switching are quantized and the characteristic images are drawn, it can be approximately considered that the ID information of the vehicle can be characterized, thereby completing the identification of the vehicle. After completing the information identification and communication connection of the vehicle, the system officially charges the electric vehicle to ensure the normal operation of the electric vehicle wireless charging system.

[0039] The EV-WPT system also includes a primary communication module arranged on the primary side and a secondary communication module arranged on the secondary side. The primary controller and the secondary controller exchange information through a wireless communication link formed by the primary communication module and the secondary communication module. In this embodiment, the primary communication module and the secondary communication module preferably use WiFi modules because WiFi is used to directly communicate with the primary controller buried underground. During the transmission process, the distance is short, and it is easy to shield interference from other parking spaces, with the advantages of high connection accuracy and no signal crosstalk.

[0040] The EV-WPT system is equipped with a charging port in each parking space. When an electric vehicle enters a parking space, it first needs to authenticate and communicate with the charging port. The specific steps are that the electric vehicle sends a signal to the power transmitter buried in the ground through the WiFi module installed on the charging port. After receiving the signal, the power transmitter changes the circuit structure by switching the secondary side topology, and then changes the output current of the primary side. Due to the different car models, the load in the access circuit will also change, so the detected primary current will also be different under different loads. The system identifies the various parameters of the primary current after A / D conversion to determine the identity information of the car, and determines whether the connection to the electric vehicle is completed, and then starts the formal charging process.

[0041] The working process of the electric vehicle wireless charging system is as follows Figure 2 As shown, the specific process is that the electric vehicle first sends a connection request signal to the power transmitter through WiFi. After the power transmitter receives the request signal, it will send a small power signal to the electric vehicle through the charging topology and change the secondary side compensation topology to identify it, and determine whether to connect to the electric vehicle through the various characteristic parameters of the primary side current. If the connection is successful, the formal wireless charging process will begin.

[0042] The primary controller identifies the identity information of the electric vehicle according to the first primary current and the second primary current, specifically comprising the steps of:

[0043] S1, the primary side controller extracts multiple types of features of the first primary side current and the second primary side current to obtain a feature combination;

[0044] S2. The feature combination is matched in a preset feature combination pool. If a consistent feature combination can be found, the vehicle model information corresponding to the consistent feature combination is used as the identity information of the electric vehicle.

[0045] In step S1, the extracted features include amplitude, phase, and frequency, and the obtained feature combination includes the amplitude of the first primary current A 1. Phase φ 1. Frequency f 1 and the amplitude of the second primary current A 2. Phase φ 2. Frequency f 2. These are typical characteristics of current waveforms.

[0046] Specifically, the primary side controller determines whether to establish a communication connection with the electric vehicle based on the identity information, specifically including:

[0047] D1. Determine whether there is a specific car model in the identity information. If yes, proceed to step D2. If not, proceed to step D3.

[0048] D2. Determine whether the electric vehicle is a model supported by the EV-WPT system according to the model (except for the models that do not match the model library, all other models are supported models). If yes, send a connection confirmation signal to the secondary side controller. If not, execute step D3.

[0049] D3 sends a connection rejection signal to the secondary controller and controls the power transmitter to stop power transmission.

[0050] In summary, the EV-WPT system for identity recognition based on receiving side topology switching provided by the embodiment of the present invention, when the electric vehicle enters the charging area, the secondary side controller sends a charging request to the primary side controller. After receiving the request signal, the primary side controller first uses a smaller power signal to identify the electric vehicle through the wireless charging system. In this process, the identity of the electric vehicle is identified by analyzing the primary side output current before and after the secondary side compensation topology switching. When the identity recognition is passed, the communication connection between the primary and secondary sides is established, and the electric vehicle starts to be charged normally, thereby avoiding charging of electric vehicles that do not match the power transmitter, and ensuring charging safety.

[0051] The present invention is based on the method of topology switching. By switching the secondary compensation topology structure, different primary current combinations can be obtained, and the primary current combination is matched with the preset primary current combination. Only when they match can the primary-secondary communication connection be established and charging is started. It has the advantages of high accuracy and simple detection. And the secondary compensation topology can also be applied in formal charging. In the fully resonant state, the LCC-S topology can achieve constant voltage charging, and the LCC-LCC topology can achieve constant current charging. Based on this, the system can select different charging schemes based on different situations. In addition, the present invention does not introduce other detection equipment, has a simple structure, and saves costs.

[0052] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An EV-WPT system for identity recognition based on receiving side topology switching, comprising an electric energy transmitting end located on the primary side and an electric energy receiving end located on the secondary side, wherein the electric energy receiving end is provided with a secondary side compensation network; characterized in that: The EV-WPT system further includes a primary side controller and a current detection circuit located on the primary side, and a secondary side controller located on the secondary side; the secondary side compensation network switches between a first secondary side compensation network and a second secondary side compensation network under the control of the secondary side controller; When the electric vehicle enters a parking space, the secondary side controller sends a connection request signal to the primary side controller, and at this time, the secondary side controller also controls the secondary side compensation network to be the first secondary side compensation network; after receiving the connection request signal, the primary side controller controls the power transmitting end to operate at low power, and controls the current detection circuit to collect the first primary side current; After receiving the first primary current, the primary controller sends a secondary topology switching signal to the secondary controller; after receiving the secondary topology switching signal, the secondary controller controls the secondary compensation network to switch to the second secondary compensation network; The primary side controller controls the current detection circuit to collect the second primary side current after sending the secondary side topology switching signal for a preset time period; the primary side controller identifies the identity information of the electric vehicle according to the first primary side current and the second primary side current, and determines whether to establish a communication connection with the electric vehicle according to the identity information, and if so, sends a connection confirmation signal to the secondary side controller; After receiving the connection confirmation signal, the secondary side controller sends a charging request to the primary side controller, and the primary side controller controls the operation of the power transmitting end according to the charging request; The secondary compensation network includes a first secondary coil L s , the second secondary coil L f2 、The first secondary capacitor C s , the second secondary capacitor C f2 and switch S, first secondary coil L s , the second secondary coil L f2 、The first secondary capacitor C s 、The first secondary capacitor C f2 The connection relationship with switch S is: When the switch S is turned off, the second secondary coil L f2 With the second secondary capacitor C f2 Connected in series, forming an S-type compensation topology, where the second secondary coil L f2 As a secondary receiving coil; When the switch S is closed, the first secondary coil L s As the secondary receiving coil, the second secondary coil L f2 、The first secondary capacitor C s , the second secondary capacitor C f2 The LCC compensation topology is formed, where the first secondary capacitor C s is the secondary side series compensation capacitor, the second secondary side capacitor C f2 is the parallel compensation capacitor; The electric energy transmitting end is provided with a primary compensation network, and the primary compensation network comprises an LCC type compensation network.

2. The EV-WPT system for identity recognition based on receiving side topology switching according to claim 1, characterized in that: The primary side controller determines whether to establish a communication connection with the electric vehicle according to the identity information, specifically: D1, determine whether there is a specific car model in the identity information, if yes, go to step D2, if not, go to step D3; D2, judging whether the electric vehicle is a vehicle model supported by the EV-WPT system according to the vehicle model, and if so, sending a connection confirmation signal to the secondary side controller, and if not, executing step D3; D3. Send a connection rejection signal to the secondary side controller, and control the power transmitting end to stop power transmission.

3. The EV-WPT system for identity recognition based on receiving side topology switching according to claim 2, characterized in that: The primary controller identifies the identity information of the electric vehicle according to the first primary current and the second primary current, specifically comprising the steps of: S1, the primary side controller extracts multiple types of features of the first primary current and the second primary current to obtain a feature combination; S2. Perform feature matching on the feature combination in a preset feature combination pool. If a consistent feature combination can be found, the vehicle model corresponding to the consistent feature combination is used as the identity information of the electric vehicle.

4. The EV-WPT system for identity recognition based on receiving side topology switching according to claim 3 is characterized in that: In step S1, the extracted multiple features include amplitude, phase, and frequency, and the obtained feature combination includes the amplitude of the first primary current A 1. Phase φ 1. Frequency f 1 and the amplitude of the second primary current A 2. Phase φ 2. Frequency f 2.

5. The EV-WPT system for identity recognition based on receiving side topology switching according to claim 1, characterized in that: The EV-WPT system also includes a primary communication module arranged on the primary side and a secondary communication module arranged on the secondary side. The primary controller and the secondary controller exchange information via a wireless communication link formed by the primary communication module and the secondary communication module.

6. The EV-WPT system for identity recognition based on receiving side topology switching according to claim 5 is characterized in that: The primary side communication module and the secondary side communication module adopt WiFi modules.

7. The EV-WPT system for identity recognition based on receiving side topology switching according to any one of claims 1 to 6, characterized in that: The primary compensation network also includes a transmitting coil L p The current detection circuit includes a connected current transformer and a measuring instrument and a protection circuit connected to the secondary side of the current transformer.

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