Vehicle charging device and vehicle charging method

Abstract

To provide a vehicle charging device and a vehicle charging method in which a charging abnormality due to poor communication quality is effectively improved.SOLUTION: In a vehicle charging system 90, a vehicle charging device 9A connected to a cloud computing platform 9D via a network 9C includes a transformer 91 and two impedance tuners 92, two communication lines 93 are disposed on one side of the transformer so as to be connected to an electric automobile 9B, and each of the two impedance tuners is connected in parallel with one of the two communication lines. Each impedance tuner includes at least one branch path 921 for adjusting a reactance property of each of the communication lines. Therefore, the impedance of each communication line can be stepwisely adjusted in accordance with the signal intensity of the communication line, the vehicle charging device and the electric automobile mutually communicate with each other in a state where impedance matching therebetween is almost achieved, and a charging abnormality caused by an excessively high bit error rate of data exchange is avoided.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to charging and communication technology, and more particularly to a vehicle charging device and a vehicle charging method. [Background technology]

[0002] As environmental awareness increases, electric vehicles and related infrastructures have become more and more popular. When charging a vehicle, the electric vehicle and a charging station can be connected to each other, and when the electric vehicle and the charging station complete the charging communication operation, the charging station supplies power to the battery of the electric vehicle.

[0003] If the bit error rate of data exchange during charging communication is too high, abnormalities such as the electric vehicle being unable to charge or charging being interrupted may occur. Although there are currently several technical means for charging control, there is still a need for improvement. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a vehicle charging device and a vehicle charging method that can effectively improve charging abnormalities caused by poor communication quality.

[0005] In order to achieve the above object, one aspect of the present invention provides a vehicle charging device including: a transformer having a first side and a second side, the second side being provided with two communication lines for connection to an electric vehicle; and two impedance tuners, each connected in parallel to one of the two communication lines and configured to adjust the reactance characteristics of the two communication lines.

[0006] In order to achieve the above object, one aspect of the present invention provides a vehicle charging method applied to a vehicle charging device, the vehicle charging device including: a transformer having a first side and a second side, the second side being provided with two communication lines to be connected to an electric vehicle; and two impedance tuners, each connected in parallel to one of the two communication lines and configured to adjust the reactance characteristics of the two communication lines. The vehicle charging method includes the steps of detecting that the two communication lines connected to the vehicle charging device are connected to the electric vehicle; the vehicle charging device performing power line communication with the electric vehicle and collecting signal strengths of multiple signal channels of the electric vehicle; the vehicle charging device monitoring communication characteristics of the two communication lines based on the signal strengths of the multiple signal channels so that the signal strengths of the two communication lines satisfy a strength requirement; and the vehicle charging device executing a charging mode for the electric vehicle in response to the signal strengths of the two communication lines satisfying the strength requirement. [Effects of the Invention]

[0007] In the vehicle charging device and vehicle charging method of the present invention, two communication lines (each having a capacitor) are provided on a second side of the transformer of the vehicle charging device to be connected to an electric vehicle, and each of the impedance tuners of the vehicle charging device is connected in parallel to one of the communication lines, and the two impedance tuners are configured to adjust the reactance characteristics of the two communication lines. For example, each of the two impedance tuners includes at least one branch path (including a switch and a capacitor), and each of the at least one branch path is connected in parallel to the capacitor of the communication line. Therefore, the connection between the capacitors of an appropriate number of branch paths and the capacitor of the communication line can be controlled in stages according to the signal strength of the communication line, and by adjusting the impedance of the communication line, the vehicle charging device and the electric vehicle can communicate with each other in a state close to impedance matching, and abnormalities such as an electric vehicle being unable to charge or being interrupted due to an excessively high bit error rate in data exchange can be avoided. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a vehicle charging system to which an embodiment of the present invention can be applied. [Figure 2] FIG. 2 is a schematic diagram of a first signal transmission mode of the vehicle charging system shown in FIG. [Figure 3] FIG. 3 is a schematic diagram of the power spectral density distribution of the communication lines in the first example charging station shown in FIG. [Figure 4] FIG. 4 is a schematic diagram of the power spectral density distribution of the communication lines in the second example charging station shown in FIG. [Figure 5] FIG. 5 is a schematic diagram of a second signal transmission mode of the vehicle charging system shown in FIG. [Figure 6] 6(a) and 6(b) are schematic diagrams of the equivalent circuit and insertion loss for the first example charging station shown in FIG. [Figure 7] 7(a) and 7(b) are schematic diagrams of the equivalent circuit and insertion loss for the second charging station example shown in FIG. [Figure 8] FIG. 8 is a schematic diagram of acquiring signal strengths of multiple signal channels in the example of multiple charging stations shown in FIG. [Figure 9] FIG. 9 is a block diagram of a vehicle charging device according to an embodiment of the present invention. [Figure 10] FIG. 10 is a schematic diagram of a connection configuration between the switches and capacitors in the branch path of FIG. [Figure 11] FIG. 11 is a flowchart of a vehicle charging method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] In order to make the above contents and other objects, features, and advantages of the present invention more clearly understandable, preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0010] As shown in FIG. 1, a vehicle charging system 10 (e.g., a combined charging system (CCS)) allows a charging stand (electric vehicle supply equipment, EVSE) 11 and an electric vehicle (EV) 12 to be interconnected. For example, the electric vehicle 12 may be a scooter-type vehicle or a car. A coupler connection (connector connection) is formed between the charging connector of the charging stand 11 and the inlet of the electric vehicle 12. When the electric vehicle 12 and the charging stand 11 complete charging communication operations, the charging stand 11 supplies power to the battery of the electric vehicle 12. If the controller 13 lacks an effective compatibility control or optimization mechanism during charging and communication operations, for example, to adjust for differences in couplers formed by different charging connectors (e.g., different wire lengths or diameters), the bit error rate (BER) of data exchange may be too high when the coupler is connected, resulting in insufficient adaptability of data communication compatibility. For example, the charging and communication operations may not be completed, causing abnormalities such as the electric vehicle being unable to charge or charging being interrupted, resulting in an unsatisfactory user experience.

[0011] For example, taking the Power Line Communication (PLC) protocol as an example, during charging communication operation, the communication mode between the charging station and the electric vehicle may be a full duplex mode that enables simultaneous bidirectional data transmission between the charging station and the electric vehicle.

[0012] As shown in FIG. 2 , in the first signal transmission mode, in the vehicle charging system 20, the controller 211 of the charging stand 21 uses signal lines (e.g., TXOUT_P and TXOUT_N) to transmit signals to the electric vehicle 22 via the transformer 212 and the communication line 23. For example, the communication line 23 may be a control pilot line (CP) and a protective earth line (PE). In this case, if the impedances of the charging stand 21 and the electric vehicle 22 do not match, the signal will be attenuated during communication. For example, the charging stand 21 can acquire the signal strengths of multiple signal channels between the charging stand 21 and the electric vehicle 22 in a sweeping manner, so that the charging stand 21 can easily acquire the power spectral density profile (PSD profile) of a specific signal.

[0013] In one application example, Fig. 3 shows an example PSD profile curve 30 of a communication line (e.g., CP) acquired by a charging station controller via a ninth channel (CH9), where the signal strength is mostly less than -40 dBm, for example, the signal strength at sampling point M1 is -43.01 dBm. In another application example, Fig. 4 shows an example PSD profile curve 40 of a communication line (e.g., CP) acquired by a controller of another charging station, where the signal strength is completely less than -40 dBm, for example, the signal strength at sampling point M1 is -45.71 dBm. There is a difference of about 6 dB between the signal strengths of the two charging stations shown in Figs. 3 and 4.

[0014] 5, in the second signal transmission mode, in the vehicle charging system 50, the controller 511 of the charging stand 51 receives a signal from the electric vehicle 52 using a signal line (e.g., RXIN_P and RXIN_N) via a bandpass filter (RX_BPF) 513 and a transformer 512 through a communication line 53, and the communication line 53 may be, for example, a control pilot line (CP) and a protective earth line (PE). In this case, if the impedances of the charging stand 51 and the electric vehicle 52 do not match, the signal will be attenuated during communication.

[0015] For example, the insertion loss of the communication lines (e.g., CP and PE) of the coupler circuit can be obtained by a bidirectional channel (e.g., CH57) of the transceiver. FIGS. 6(a) and 6(b) show an example equivalent circuit 60a and an example insertion loss curve 60b of a charging station, respectively. The example insertion loss curve 60b indicates that the insertion loss (S21) of the example equivalent circuit 60a is approximately −20.49 dB in the frequency band of 150 kHz to 30 MHz. FIGS. 7(a) and 7(b) show an example equivalent circuit 70a and an example insertion loss curve 70b of another charging station, respectively. The example insertion loss curve 70b indicates that the insertion loss (S21) of the example equivalent circuit 70a is approximately −25.17 dB in the frequency band of 150 kHz to 30 MHz. The difference in insertion loss between the two charging stations shown in FIGS. 6(b) and 7(b) is approximately 5 dB.

[0016] FIG. 8 shows example signal strength curves 80 of multiple signal channels (e.g., carrier channels CH0 to CH57) acquired from multiple charging stations. All three curves C1, C2, and C3 show a trend of signal strength attenuation as the frequency of the carrier channel (CHx, x = 0 to 57) increases, with approximately two-thirds of the channels having signal strengths below -31 dB. The received signal strength (e.g., CH57) profile value of the communication line (e.g., CP) of the coupler circuit is approximately -60 dB to -66 dB (lower than the range of -20 dB to -39 dB).

[0017] As can be seen from the above, during charging communication operations, the charging stand and the electric vehicle communicate with each other via two communication lines (e.g., CP and PE), and if an impedance mismatch occurs between the charging stand and the electric vehicle, the signal will be attenuated during communication, preventing the communication operation from being completed and possibly resulting in charging abnormalities.

[0018] For example, this specification uses power line communication (PLC) as the charging communication technology based on the ISO-15118-3 / IEC-61851-1 standard. The two communication lines in a charging station are a control pilot line (CP) and a protective earth line (PE). Each of these lines has a capacitance characteristic, which is an important factor affecting the charging communication operation. This is because, at least in part, charging stations need to supply power to electric vehicles of different manufacturers, and the impedance states of each electric vehicle are different.

[0019] Therefore, to avoid impedance mismatch between the charging stand and the electric vehicle, the charging stand needs to have a communication impedance adjustment capability to match electric vehicles in different impedance states. When the charging stand and the electric vehicle are connected to form a coupler, the impedances of the charging stand and the electric vehicle on both sides of the coupler tend to match, avoiding serious signal attenuation caused by impedance mismatch and easily completing the charging communication operation.

[0020] As described above, the present invention provides a method for realizing this. For example, during charging and communication operation, the charging station and the electric vehicle communicate with each other via two communication lines (e.g., CP and PE), and the control method in which the communication lines (e.g., CP and PE) operating in an open loop form a coupler can employ a control method in which the communication lines (e.g., CP and PE) adjust their impedance (Impedance Tuning). Examples are shown below, but the present invention is not limited to these.

[0021] For example, the communication line impedance adjustment method may be a method of adjusting the reactance characteristics (including inductive reactance and capacitive reactance) of the communication line based on the characteristics of the communication line itself. When the charging station and the electric vehicle form a coupler connection state and enter a data transmission mode, the signal strength of the communication line (e.g., CP and PE) is obtained in a specific manner (e.g., by scanning a specific channel or executing a specific command by the controller). Specifically, the controller of the charging station sends a command "CM_ATTEN_CHAR.IND" to obtain the "ATTEN_PROFILE" content as signal attenuation profile information. This allows the signal characteristics of the communication line to be quickly obtained.

[0022] Therefore, the present invention provides a control method for adjusting its own impedance to facilitate the data transmission mode (or diagnostic adjustment procedure), and the coupler formed by the charging station and the electric vehicle has the function of detecting the communication line (e.g., CP and PE) in a closed loop and adjusting the impedance, thereby improving the data transmission quality and avoiding the inability to complete the communication operation or charging abnormalities due to signal attenuation during communication.

[0023] In one embodiment, after the relevant data is collected, it is further used to understand the impedance matching information of the communication lines (e.g., CP and PE) of different electric vehicles, evaluate the characteristics of the communication lines applicable to different vehicles, create a charging impedance adjustment method applicable to different vehicles, improve the compatibility and adaptability of charging, and achieve the effect of optimizing the vehicle charging process.

[0024] The present invention provides implementation methods based on the above technical means, examples of which are given below, but are not limited thereto.

[0025] On the other hand, as shown in FIG. 9, an embodiment of the present invention provides a vehicle charging device, for example, in a vehicle charging system 90 (e.g., CCS), a vehicle charging device 9A and an electric vehicle 9B are interconnected, and the vehicle charging device 9A may be configured to form a charging station for a vehicle (e.g., a scooter-type vehicle or an automobile), and includes a transformer 91 and two impedance tuners 92.

[0026] For example, as shown in FIG. 9 , a transformer 91 has a first side and a second side. The first side of the transformer 91 can transmit and receive signals from an electronic device via a transmission signal line (e.g., SPI_TX+ and SPI_TX−) and a reception signal line (e.g., SPI_RX+ and SPI_RX−) of a signal line (e.g., a serial peripheral interface (SPI)). The first side of the transformer 91 can receive signals from a controller (e.g., a power line communication chipset (PLC chipset), see 211 in FIG. 2 and 511 in FIG. 5), and the controller can collect signal strengths of multiple signal channels as a reference for communication and control. The second side of the transformer 91 is provided with two communication lines 93 for connecting an electric vehicle 9B.

[0027] For example, as shown in FIG. 9, each of the two impedance tuners 92 is connected in parallel to one of the two communication lines 93, and the two impedance tuners 92 are configured to adjust the reactance characteristics of the two communication lines 93, and for example, each impedance tuner 92 may include at least one branch path 921 for adjusting the reactance characteristics of the communication line 93, as described below.

[0028] For example, as shown in FIG. 9 , each of the communication lines 93 has a first capacitor 94, and each of the impedance tuners 92 includes at least one branch path 921 connected in parallel to the first capacitor 94. For example, each of the branch paths 921 includes a switch 95 and a second capacitor 96, and the switch 95 and the second capacitor 96 are connected in series. The switch 95 for each branch path 921 is configured to form a parallel circuit or an open circuit with the first capacitor 94 and the second capacitor 96 in response to a control signal from a controller (e.g., a PLC chipset), and gradually adjust (e.g., increase or decrease) the number of second capacitors 96 connected in parallel to the first capacitor 94 to adjust the equivalent capacitance value of the communication line 93 from 10 nF to 20 nF, etc., but is not limited to this.

[0029] 9 , the more switches 95 of the branch path 921 are turned on (Turn ON), the more second capacitors 96 that form parallel circuits with the first capacitor 94 are present, which increases the equivalent capacitance value of the communication line 93 and the equivalent capacitance impedance (ZC) of the communication line 93. On the other hand, the fewer switches 95 of the branch path 921 are turned on (Turn ON), the fewer second capacitors 96 that form parallel circuits with the first capacitor 94 are present, which decreases the equivalent capacitance value of the communication line 93 and the equivalent capacitance impedance (ZC) of the communication line 93. Therefore, the vehicle charging device 9A can control the number of second capacitors 96 that form parallel circuits with the first capacitor 94 using the switches 95 of each branch path 921 as a criterion for adjusting the reactance characteristics of the communication line 93 in accordance with the signal strength of the communication line 93.

[0030] When adjusting the impedance state of the communication line, since the signal frequency of the communication line is relatively high (for example, a frequency band of 150 kHz to 30 MHz), the signal frequency of the communication line must be taken into consideration when selecting the switch in order to adjust the impedance state of the communication line in immediate response to the signal strength of the communication line. Here, only a case where the impedance tuner includes one branch path will be described as an example, but the present invention is not limited to this.

[0031] 10, vehicle charging system 100 includes vehicle charging device 10A and electric vehicle 10B, vehicle charging device 10A includes transformer 101 and two impedance tuners 102, each of two impedance tuners 102 is connected in parallel to one of two communication lines 103, each communication line 103 has a first capacitor 104, and each impedance tuner 102 includes at least one branch path 1021 (only one branch path 1021 is shown in FIG. 10). For example, each branch path 1021 includes switch 105 and second capacitor 106, and switch 105 may be a high-frequency switch element, and the operating frequency range of switch 105 includes, but is not limited to, 150 kHz to 30 MHz, for example.

[0032] 10, in order to ensure the switching speed of the switch and avoid signal interference, etc., the switch 105 may be a chip-type switch. For example, the chip-type switch has a control terminal CTL and two connection terminals CN1 and CN2, and a second capacitor 106 is connected between one of the two connection terminals CN1 and CN2 (e.g., CN1) and one end of the first capacitor 104, and the other of the two connection terminals CN1 and CN2 (e.g., CN2) is connected to the other end of the first capacitor 104. Also, as shown in FIG. 10, the switch 105 may further include other components, such as a power supply terminal VD (used for external connection to a DC power supply VDD) and multiple ground terminals GND (used for electrical grounding), and a resistor R may be provided between the control terminal CTL and the ground terminal GND, so that the control terminal CTL maintains an appropriate control voltage difference to control the switching state between the two connection terminals CN1 and CN2 to ON or OFF.

[0033] Referring again to FIG. 9 , a vehicle charging device 9A may be connected to a cloud computing platform 9D via a network 9C. For example, a charging connector plug provided by the vehicle charging device 9A can be inserted into an inlet of an electric vehicle 9B. When the vehicle charging device 9A and the electric vehicle 9B are coupled together, the vehicle charging device 9A can collect signal strength information and vehicle-related information (e.g., manufacturer, model number, etc.) to determine whether the impedance of the communication line needs to be adjusted. The information collected by the vehicle charging device 9A can be aggregated via the network 9C and stored in the cloud computing platform 9D for big data analysis, which is useful for identifying impedance matching methods to be applied to different vehicles during charging communication. For similar vehicles, the vehicle charging device 9A can then adjust the impedance matching state of the communication line by referring to a recommended impedance matching method (e.g., provided by the cloud computing platform) to smoothly complete the charging communication operation and perform subsequent charging mode operations.

[0034] Meanwhile, as shown in Fig. 11, an embodiment of the present invention provides an example vehicle charging method 110, which is applicable to the above-mentioned vehicle charging device (for example, the vehicle charging device 9A shown in Fig. 9 may be configured as a charging station for electric vehicles), and includes steps 111 to 115. Examples are shown below, but the present invention is not limited to these.

[0035] As shown in FIG. 11, in step 111, an electric vehicle is connected to a charging station, and for example, the vehicle charging device 9A shown in FIG. 9 detects the connection between the two communication lines 93 connected to the vehicle charging device 9A and the electric vehicle 9B, and then proceeds to step 112.

[0036] As shown in FIG. 11, in step 112, a power line communication operation is performed, for example, the vehicle charging device 9A and the electric vehicle 9B shown in FIG. 9 perform power line communication (PLC), and the vehicle charging device 9A collects the signal strength of multiple signal channels of the electric vehicle 9B, and then proceeds to step 113.

[0037] As shown in FIG. 11, in step 113, the impedance matching of the communication lines is adjusted. For example, the vehicle charging device 9A shown in FIG. 9 monitors the communication characteristics of the two communication lines 93 according to the signal strengths of multiple signal channels to ensure that the signal strengths of the two communication lines 93 meet the strength requirement. For example, the vehicle charging device 9A shown in FIG. 9 calculates an average signal strength according to the signal strengths of the multiple signal channels. For example, the average signal strength is equal to the quotient of the sum of the multiple signal strengths and the number of signal strengths. Based on the average signal strength and a signal strength threshold (for example, but not limited to, −31 dB), the vehicle charging device 9A confirms that the signal strengths of the two communication lines 93 meet the strength requirement. For example, the controller of the vehicle charging device 9A determines whether the average signal strength is lower than the signal strength threshold. If it is determined to be lower, the controller of the vehicle charging device 9A gradually adjusts the impedance of the two communication lines 93. For example, the vehicle charging device 9A can increase the equivalent capacitance values ​​of the two communication lines 93 by a predetermined amount (e.g., by increasing the number of capacitors connected in parallel) to bring the impedances between the vehicle charging device 9A and the electric vehicle 9B closer to matching, thereby improving the average signal strength, and then perform the above calculation and judgment steps again. If it is determined that the signal strength is not low, the controller of the vehicle charging device 9A confirms that the signal strength of the two communication lines 93 meets the strength requirement, and then performs step 114.

[0038] As shown in FIG. 11, in step 114, communication is completed and the charging mode is entered. For example, as shown in FIG. 9, in response to the signal strength of the two communication lines 93 satisfying the strength requirement, the vehicle charging device 9A performs the charging mode for the electric vehicle 9B. For example, the vehicle charging device 9A can collect characteristic information of the electric vehicle 9B (e.g., the signal strength and impedance characteristics of the communication lines 93, the vehicle model, etc.) before or during the charging process and transmit the characteristic information to the cloud computing platform 9D. The cloud computing platform 9D can generate a charging method for the vehicle charging device 9A based on the characteristic information, and the vehicle charging device 9A can charge the electric vehicle 9B based on the charging method. This makes it possible to quickly and appropriately provide a charging method using big data content and reduce the occurrence of charging abnormalities.

[0039] As shown in FIG. 11, the example vehicle charging method 110 includes a step 115 of completing charging. For example, as shown in FIG. 9, in the charging mode, for example, the electric vehicle 9B can feed back remaining power information to the vehicle charging device 9A. When the vehicle charging device 9A detects that the remaining power of the battery of the electric vehicle 9B is equal to or greater than a remaining power threshold, the vehicle charging device 9A can complete the charging mode. For example, the vehicle charging device 9A can output charging completion information, for example, display it on a screen, emit a sound, or send a message to notify the user that the electric vehicle 9B is in a charging completion state.

[0040] In summary, in the vehicle charging device and vehicle charging method of the present invention, two communication lines (each having a capacitor) are provided on a second side of the transformer of the vehicle charging device to be connected to an electric vehicle, and each of the impedance tuners of the vehicle charging device is connected in parallel to one of the communication lines, and the two impedance tuners are configured to adjust the reactance characteristics of the two communication lines, for example, each of the two impedance tuners includes at least one branch path (including a switch and a capacitor), and each of the at least one branch path is connected in parallel to the capacitor of the communication line. Thus, the connections between the capacitors of an appropriate number of branch paths and the capacitors of the communication lines can be controlled in stages according to the signal strength of the communication lines, and by adjusting the impedance of the communication lines, the vehicle charging device and the electric vehicle can communicate with each other in a state close to impedance matching, and abnormalities such as an electric vehicle being unable to charge or being interrupted due to an excessively high bit error rate in data exchange can be avoided.

[0041] Although the present invention has been disclosed in preferred embodiments, those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and therefore the scope of protection of the present invention is deemed to be defined by the appended claims. [Explanation of symbols]

[0042] 10, 20, 50, 90, 100 Vehicle Charging System 11, 21, 51 Charging Station 12, 22, 52, 9B, 10B electric vehicles 13, 211, 511 Controller 30, 40 PSD profile curve example 91, 101, 212, 512 transformers 92, 102 Impedance Tuner 921, 1021 Branch Route 23, 53, 93, 103 communication lines 513 Bandpass Filter 60a, 70a equivalent circuit example 60b, 70b insertion loss curve example 80 Example signal strength curve 94, 104 First capacitor 95, 105 switches 96, 106 Second capacitor 9A, 10A vehicle charging equipment 9C Network 9D Cloud Computing Platform 110 Example of vehicle charging method Steps 111, 112, 113, 114, and 115 SPI_TX+, SPI_TX-, SPI_RX+, SPI_RX-, TXOUT_P, TXOUT_N, RXIN_P, RXIN_N signal lines C1, C2, C3 curves CP Control Pilot Wire PE protective earth wire CTL control terminal CN1, CN2 connection terminals VD power supply terminal VDD DC power supply GND Grounding terminal R resistance M1 sampling point

Claims

1. a transformer having a first side and a second side, the second side being provided with two communication lines for connection to an electric vehicle; two impedance tuners, each connected in parallel to one of the two communication lines and configured to adjust the reactance characteristics of the two communication lines.

2. 2. The vehicle charging apparatus of claim 1, wherein each of the two communication lines has a first capacitor, and each of the two impedance tuners includes at least one branch path, and each of the at least one branch path is connected in parallel to the first capacitor.

3. The vehicle charging device of claim 2 , wherein each of the at least one branch path includes a switch and a second capacitor, the switch and the second capacitor being connected in series.

4. The vehicle charging apparatus of claim 3 , wherein the switch is configured to cause the first capacitor and the second capacitor to form a parallel circuit or an open circuit based on a control signal from a controller.

5. 4. The vehicle charging device of claim 3, wherein the switch is a high frequency switch element.

6. 6. The vehicle charging device according to claim 5, wherein the high frequency switch element has an operating frequency range of 150 kHz to 30 MHz.

7. 6. The vehicle charging device according to claim 5, wherein the high-frequency switch element is a chip-type switch having a control terminal and two connection terminals, the second capacitor is connected between one of the two connection terminals and one end of the first capacitor, and the other of the two connection terminals is connected to the other end of the first capacitor.

8. 2. The vehicle charging apparatus of claim 1, wherein the two communication lines include a control pilot line and a protective ground line.

9. The vehicle charging device of claim 1 , wherein the vehicle charging device is connected to a cloud computing platform via a network.

10. 1. A vehicle charging method applied to a vehicle charging device including: a transformer having a first side and a second side, the second side being provided with two communication lines to be connected to an electric vehicle; and two impedance tuners, each connected in parallel to one of the two communication lines and configured to adjust reactance characteristics of the two communication lines, detecting a connection between the electric vehicle and two communication lines connected to the vehicle charging device; The vehicle charging device and the electric vehicle are in power line communication, and the vehicle charging device collects signal strengths of a plurality of signal channels of the electric vehicle; The vehicle charging device monitors communication characteristics of the two communication lines based on the signal strengths of the plurality of signal channels to ensure that the signal strengths of the two communication lines meet a strength requirement; and in response to the signal strength of the two communication lines satisfying the strength requirement, the vehicle charging device performs a charging mode for the electric vehicle.

11. The step of the vehicle charging device monitoring the communication characteristics of the two communication lines based on the signal strengths of the plurality of signal channels to ensure that the signal strengths of the two communication lines meet the strength requirement includes: The vehicle charging device calculates an average signal strength based on the signal strengths of the plurality of signal channels; 11. The vehicle charging method of claim 10, further comprising: the vehicle charging device verifying that the signal strengths of the two communication lines meet the strength requirements based on the average signal strength and a signal strength threshold.

12. The vehicle charging device determines whether the signal strengths of the two communication lines satisfy the strength requirement based on the average signal strength and the signal strength threshold.

12. The vehicle charging method of claim 11, wherein the vehicle charging device determines whether the average value of the signal strength is lower than the signal strength threshold, and if it is determined that it is lower, the vehicle charging device increases the equivalent capacitance value of the two communication lines by a predetermined amount and performs the calculation and the determination again, and if it is determined that it is not lower, the vehicle charging device confirms that the signal strength of the two communication lines meets the strength requirement.

13. 12. The vehicle charging method of claim 11, wherein the signal strength threshold is −31 dB.

14. The vehicle charging device is connected to a cloud computing platform via a network, and the vehicle charging method includes: The vehicle charging device collects characteristic information of the electric vehicle and sends the characteristic information to the cloud computing platform; The cloud computing platform generates a charging method for the vehicle charging device based on the characteristic information; The vehicle charging method according to claim 10 , further comprising the step of: the vehicle charging device charging the electric vehicle based on the charging method.

15. 11. The vehicle charging method of claim 10, wherein each of the two communication lines has a first capacitor, and each of the two impedance tuners includes at least one branch path, and each of the at least one branch path is connected in parallel to the first capacitor.

16. 16. The vehicle charging method of claim 15, wherein each of the at least one branch path includes a switch and a second capacitor, the switch and the second capacitor being connected in series.

17. 17. The vehicle charging method of claim 16, wherein the switch is configured to cause the first capacitor and the second capacitor to form a parallel circuit or an open circuit based on a control signal from a controller.

18. 17. The method of claim 16, wherein the switch is a high frequency switch element.

19. 19. The vehicle charging method according to claim 18, wherein the operating frequency range of the high frequency switch element includes 150 kHz to 30 MHz.

20. 19. The vehicle charging method according to claim 18, wherein the high-frequency switch element is a chip-type switch having a control terminal and two connection terminals, the second capacitor is connected between one of the two connection terminals and one end of the first capacitor, and the other of the two connection terminals is connected to the other end of the first capacitor.

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