Wireless charging dynamic frequency adjustment system and vehicle

Abstract

The application relates to a wireless charging dynamic frequency adjustment system and a vehicle, which comprises a ground wireless charging module and a vehicle end wireless charging module, the vehicle end wireless charging module is provided with a vehicle coupling circuit, the vehicle coupling circuit comprises a coupling coil and a capacitance adjustable circuit, the capacitance adjustable circuit comprises a plurality of resonance capacitors, and a controller in the vehicle end wireless charging module controls the resonance capacitors in the capacitance adjustable circuit to cut in or cut out so as to realize adjustment of the working frequency of the coupling coil. When the working frequency of the coupling coil is inconsistent with the set working frequency, a set number of resonance capacitors are cut in or cut out, the working frequency of the coupling coil is detected again, if the working frequency of the coupling coil is close to the set working frequency, the capacitance is continuously adjusted in the same adjustment capacitance mode as the last time until the set working frequency is reached. If the working frequency of the coupling coil is far away from the set working frequency, the capacitance is adjusted in the opposite adjustment capacitance mode as the last time until the set working frequency is reached.

Description

Technical Field

[0001] This invention relates to a wireless charging dynamic frequency adjustment system and vehicle, belonging to the field of electric vehicle charging technology. Background Technology

[0002] With advancements in power electronics, battery technology, and electric vehicle technology, wireless power transfer technology has experienced rapid development in the electric vehicle application field. Wireless charging systems for electric vehicles have no exposed ports, require no manual operation, do not occupy ground space, and can achieve charging in both stationary and moving states. Therefore, compared to wired charging methods, they offer advantages such as operational safety, intelligent charging, flexible configuration, and strong environmental adaptability, and are receiving increasing attention.

[0003] The frequency characteristics of a wireless charging system mainly include frequency consistency and selectivity. Frequency consistency means that the system's operating efficiency can only be achieved when the self-resonant frequencies of the transmitting and receiving coils are the same; otherwise, the system's transmission efficiency will be greatly reduced. Frequency selectivity means that the energy to be transferred can only be effectively transferred at the frequency that matches the system's self-resonant frequency, while energy at other frequencies will be significantly attenuated or almost impossible to transfer.

[0004] The receiver of a wireless charging system is typically installed in the vehicle chassis, and according to relevant standards, its operating temperature range is generally -40℃ to +85℃. Figure 1 As shown, within this temperature range, the resonant capacitor and coil inductance within the receiving device are affected to varying degrees, causing parameter changes and resulting in a deviation between the receiving device's self-resonant frequency and the system's operating frequency. Without intervention, the system's transmission efficiency will decrease, overall energy loss will increase, leading to a shorter system lifespan and increased maintenance and after-sales costs. Summary of the Invention

[0005] The purpose of this invention is to provide a wireless charging dynamic frequency adjustment system and vehicle to solve the problem that the system's self-resonant frequency and system operating frequency deviate due to the influence of environmental factors on the resonant capacitor and inductor parameters.

[0006] To achieve the above objectives, the present invention includes:

[0007] This invention discloses a wireless charging dynamic frequency adjustment system, comprising a ground-side wireless charging module and a vehicle-side wireless charging module. The vehicle-side wireless charging module includes a vehicle coupling circuit connected to a rectifier module. The vehicle coupling circuit comprises a vehicle coupling coil and an adjustable capacitor circuit for connecting a resonant capacitor to the vehicle-side coupling circuit. The adjustable capacitor circuit includes several resonant capacitors. The vehicle-side wireless charging module also includes a controller connected to the adjustable capacitor circuit to control the resonant capacitors to switch into or out of the vehicle coupling circuit, thereby achieving frequency adjustment of the vehicle coupling circuit. The controller also collects the operating frequency of the vehicle coupling circuit.

[0008] When the operating frequency of the vehicle coupling circuit deviates from the set operating frequency, the adjustable capacitor circuit is controlled to switch in or out a set number of resonant capacitors. When the operating frequency of the vehicle coupling circuit is collected again, if the operating frequency of the vehicle coupling circuit is closer to the set operating frequency, the number of resonant capacitors in the vehicle coupling circuit is adjusted according to the previous adjustment direction; if the operating frequency of the vehicle coupling circuit is far from the set operating frequency, the number of resonant capacitors in the vehicle coupling circuit is adjusted in the opposite direction to the previous adjustment direction, until the operating frequency of the vehicle coupling circuit reaches the set operating frequency. The adjustment direction includes switching in to increase the resonant capacitors in the vehicle coupling circuit and switching out to decrease the resonant capacitors in the vehicle coupling circuit.

[0009] This invention provides a wireless charging dynamic frequency adjustment system, which consists of a ground wireless charging module and a vehicle-side wireless charging module. The vehicle-side wireless charging module is equipped with a vehicle coupling circuit, which includes a coupling coil and a capacitor adjustable circuit. The capacitor adjustable circuit includes several resonant capacitors. The controller in the vehicle-side wireless charging module controls the switching in or out of the resonant capacitors in the capacitor adjustable circuit to change the capacitor parameters in the vehicle coupling circuit, thereby adjusting the operating frequency of the coupling circuit.

[0010] Due to environmental factors such as temperature, the capacitance and inductance parameters in the coupling circuit will change, causing the operating frequency of the vehicle coupling circuit to deviate from the set operating frequency (the operating frequency is specified by national standards). When the operating frequency of the vehicle coupling circuit is inconsistent with the set operating frequency, the energy transmission efficiency will decrease. Considering that the coupling coil in the coupling circuit is arranged under the vehicle chassis and needs to form electromagnetic coupling with the coil buried in the ground, its inductance parameter is not easy to adjust. This invention adjusts the operating frequency of the coupling circuit by switching in or out a set number of resonant capacitors through an adjustable capacitor circuit when the operating frequency deviates.

[0011] After each adjustment, when the operating frequency of the vehicle coupling circuit is detected again and found to be moving closer to the set operating frequency, the number of capacitors in the coupling circuit is adjusted in the same direction as the previous adjustment. If it moves further away, it is adjusted in the opposite direction (for example, if the capacitor moves closer to the set operating frequency after increasing it, it is increased again; otherwise, it is decreased) until the operating frequency of the vehicle coupling circuit reaches the set operating frequency.

[0012] When environmental factors affect the parameters of resonant capacitor and inductor, this invention can adapt the inductor parameters by increasing or decreasing the capacitor, ensuring that the inductor and capacitor are compatible and that the self-resonant frequency is within the range of the set operating frequency, thereby maximizing the system's transmission efficiency.

[0013] Furthermore, it also includes a zero-crossing detection circuit connected to the controller, which collects the operating frequency of the vehicle coupling circuit.

[0014] The operating frequency is acquired and calculated through a zero-crossing detection circuit, a mature and reliable technology.

[0015] Furthermore, the adjustable capacitor circuit includes several capacitor branches connected in parallel. The adjustable capacitor circuit is connected in series with the vehicle coupling coil. Each capacitor branch includes a series-connected switching element and a resonant capacitor. The controller controls the connection of each switching element to control the on / off state of the corresponding capacitor branch, thereby realizing the switching on and off of the resonant capacitor.

[0016] In the adjustable capacitor circuit of the present invention, the capacitor and the switching element are connected in series to form a capacitor branch, and the capacitor branches are connected in parallel. By connecting and disconnecting the parallel capacitor branches, the sensitivity of the capacitor to temperature is reduced, and lower-cost capacitors can be selected, saving costs and making the circuit simple and convenient.

[0017] Furthermore, the ground-side wireless charging module includes a ground coupling circuit, which includes a ground coupling coil for coupling with the vehicle coupling coil and a capacitor adjustable circuit. The capacitor adjustable circuit includes several resonant capacitors. The ground-side wireless charging module also includes a controller, which is connected to the capacitor adjustable circuit to control the resonant capacitors to switch into or out of the ground coupling circuit, thereby realizing the adjustment of the operating frequency of the ground coupling circuit. The controller also collects the operating frequency of the ground coupling circuit.

[0018] When the operating frequency of the ground coupling circuit deviates from the set operating frequency, the adjustable capacitor circuit is controlled to switch in or out a set number of resonant capacitors. When the operating frequency of the ground coupling circuit is collected again, if the operating frequency of the ground coupling circuit is closer to the set operating frequency, the number of resonant capacitors in the ground coupling circuit is adjusted according to the previous adjustment direction; if the operating frequency of the ground coupling circuit is far from the set operating frequency, the number of resonant capacitors in the ground coupling circuit is adjusted in the opposite direction to the previous adjustment direction, until the operating frequency of the ground coupling circuit reaches the set operating frequency. The adjustment direction includes switching in to increase the resonant capacitors in the ground coupling circuit and switching out to decrease the resonant capacitors in the ground coupling circuit.

[0019] The ground wireless charging module in this system is equipped with a ground coupling circuit, which includes a coupling coil and an adjustable capacitor circuit. The adjustable capacitor circuit contains several resonant capacitors. The controller in the ground wireless charging module controls the switching in or out of the resonant capacitors in the adjustable capacitor circuit to adjust the operating frequency of the ground coupling circuit.

[0020] The ground coupling circuit is adjusted in the same way as the vehicle coupling circuit. By adjusting the number of resonant capacitors in the ground coupling circuit, the capacitance value is adjusted to regulate the self-resonant frequency of the ground capacitor and inductor. This keeps the self-resonant frequency of the ground wireless charging module within the set operating frequency range, thereby maximizing the transmission efficiency of the ground wireless charging module.

[0021] Furthermore, the adjustable capacitor circuit includes several capacitor branches connected in parallel. The adjustable capacitor branch is connected in series with the ground coupling coil. The capacitor branch includes a series-connected switching element and a resonant capacitor. The controller controls the connection of each switching element to control the on / off state of the corresponding capacitor branch, thereby realizing the switching on and off of the resonant capacitor.

[0022] Furthermore, the switching element is a MOSFET.

[0023] The present invention discloses a vehicle, including a vehicle-side wireless charging module. The vehicle-side wireless charging module includes a vehicle coupling circuit connected to a rectifier module. The vehicle coupling circuit includes a vehicle coupling coil and an adjustable capacitor circuit for connecting a resonant capacitor to the vehicle-side coupling circuit. The adjustable capacitor circuit includes a plurality of resonant capacitors. The vehicle-side wireless charging module also includes a controller connected to the adjustable capacitor circuit to control the resonant capacitors to switch into or out of the vehicle coupling circuit, thereby adjusting the operating frequency of the vehicle coupling circuit. The controller also acquires the operating frequency of the vehicle coupling circuit.

[0024] When the operating frequency of the vehicle coupling circuit deviates from the set operating frequency, the adjustable capacitor circuit is controlled to switch in or out a set number of resonant capacitors. When the operating frequency of the vehicle coupling circuit is collected again, if the operating frequency of the vehicle coupling circuit is closer to the set operating frequency, the number of resonant capacitors in the vehicle coupling circuit is adjusted according to the previous adjustment direction; if the operating frequency of the vehicle coupling circuit is far from the set operating frequency, the number of resonant capacitors in the vehicle coupling circuit is adjusted in the opposite direction to the previous adjustment direction, until the operating frequency of the vehicle coupling circuit reaches the set operating frequency. The adjustment direction includes switching in to increase the resonant capacitors in the vehicle coupling circuit and switching out to decrease the resonant capacitors in the vehicle coupling circuit.

[0025] The present invention also provides a vehicle equipped with a vehicle-side wireless charging module, which includes a vehicle coupling circuit. The vehicle coupling circuit includes a coupling coil and a capacitor adjustable circuit. The capacitor adjustable circuit includes several resonant capacitors. A controller in the vehicle-side wireless charging module controls the switching in or out of the resonant capacitors in the capacitor adjustable circuit to adjust the operating frequency of the vehicle coupling circuit.

[0026] When the operating frequency of the vehicle coupling circuit is inconsistent with the set operating frequency, a set number of resonant capacitors are switched in or out. The operating frequency of the vehicle coupling circuit is then detected again. If the operating frequency of the vehicle coupling circuit is moving closer to the set operating frequency, the capacitors are adjusted in the same way as before, i.e., switched in or out, until the operating frequency of the vehicle coupling circuit reaches the set operating frequency. If the operating frequency of the vehicle coupling circuit is far from the set operating frequency, the capacitors are adjusted in the opposite way as before, i.e., switched in or out, until the operating frequency of the vehicle coupling circuit reaches the set operating frequency. This ensures high-efficiency wireless charging of the vehicle and reduces vehicle wear and tear.

[0027] Furthermore, it also includes a zero-crossing detection circuit connected to the controller, which acquires the operating frequency of the vehicle coupling circuit.

[0028] Furthermore, the adjustable capacitor circuit includes several capacitor branches connected in parallel. The adjustable capacitor circuit is connected in series with the vehicle coupling coil. Each capacitor branch includes a series-connected switching element and a resonant capacitor. The controller controls the connection of each switching element to control the on / off state of the corresponding capacitor branch, thereby realizing the switching on and off of the resonant capacitor.

[0029] Furthermore, the switching element is a MOSFET. Attached Figure Description

[0030] Figure 1 This is a graph showing the change in magnetic permeability with temperature in the background technology.

[0031] Figure 2This is a block diagram of the wireless charging dynamic frequency adjustment system of the present invention;

[0032] Figure 3 This is the capacitor control circuit diagram of the present invention;

[0033] Figure 4 This is the overall flowchart of the present invention. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings.

[0035] System Implementation Example:

[0036] This invention provides a wireless charging dynamic frequency adjustment system. The system operates under varying conditions, durations, and ambient temperatures. The temperature within the receiving device also changes, constantly affecting the soft magnetic materials and capacitors, thus influencing the self-resonant frequency. The self-resonant frequency refers to the frequency at which capacitive reactance equals inductive reactance. The system incorporates an adjustable capacitor circuit, controlling the switching in and out of capacitors with different capacitance values ​​to adapt to the inductance and address this frequency variation.

[0037] Based on the operating frequency of the designed system and the formulas for the oscillation frequencies of the inductor and capacitor:

[0038]

[0039] Where f represents the oscillation frequency, L represents the inductance value, and C represents the capacitance value.

[0040] In the formula, both L and C change under the influence of temperature. After normalization, the change in inductance is ignored, and the capacitor is adjusted to ensure that the entire working state is in full resonance. When the operating frequency of the system is the same as the self-resonant frequency, the transmission efficiency of the system is optimal.

[0041] like Figure 2 The diagram shows the wireless charging dynamic frequency adjustment system of the present invention. The system includes a ground-side wireless charging module and a vehicle-side wireless charging module. The ground-side wireless charging module includes a PFC rectifier module, a high-frequency inverter module, and a ground coupling circuit. The vehicle-side wireless charging module includes a power battery, a DC-DC converter module, a high-frequency rectifier module, and a vehicle coupling circuit. The vehicle coupling circuit includes a vehicle coupling coil and an adjustable capacitor circuit. The adjustable capacitor circuit adjusts the frequency in the vehicle coupling circuit by increasing or decreasing the resonant capacitor. The ground coupling circuit includes a ground coupling coil and an adjustable capacitor circuit. The ground coupling coil is coupled to the vehicle coupling coil. The adjustable capacitor circuit can also adjust the frequency in the ground coupling circuit by increasing or decreasing the resonant capacitor.

[0042] The ground-based wireless charging module obtains high-voltage AC power from the power grid, uses a PFC rectifier module to improve the power factor of the AC power, and rectifies the AC power into DC power. Then, a high-frequency inverter module inverts the DC power back into AC power. The AC power passes through a ground coupling circuit. The ground coupling coil in the ground coupling circuit generates a magnetic field under the influence of the AC power. The vehicle coupling coil, coupled to the ground coupling coil, generates a current under the influence of the magnetic field (system energy is transferred from the ground end to the vehicle end through resonant coupling). The current is input to the power battery through the high-frequency rectifier module and the DC-DC converter module, supplying power to the power battery (system energy is then further rectified and filtered to supply energy to the power battery).

[0043] Based on the connection method between the coupling coil and capacitor circuit in the ground coupling circuit (transmitter) and the vehicle coupling circuit (receiver), the wireless charging frequency adjustment system is divided into four basic structures: series-series (SS), series-parallel (SP), parallel-series (PS), and parallel-parallel (PP). This invention takes the series-series (SS) as an example; the other methods are similar to those in this embodiment.

[0044] The ground coupling coil and the adjustable capacitor circuit form the ground resonant cavity (ground coupling circuit), which is the transmitting end. The vehicle coupling coil and the adjustable capacitor circuit form the vehicle resonant cavity (vehicle coupling circuit), which is the receiving end. The vehicle resonant cavity is installed in the vehicle chassis and has strict temperature requirements. The temperature change of the ground resonant cavity is smaller than that of the vehicle resonant cavity.

[0045] The vehicle-end resonant cavity uses a capacitor-adjustable circuit, while the ground resonant cavity uses an adjustable capacitor circuit. Both the capacitor-adjustable circuit and the adjustable capacitor circuit employ... Figure 3 The circuit structure shown has individual capacitors (C01, C02, ... C0). n ) and MOSFETs (Q1, Q2, ... Q n A series connection forms a single branch, and several (two or more) single branches are connected in parallel to form a capacitor circuit. In the ground-side wireless charging module and the vehicle-side wireless charging module, the controller controls the MOSFET switches (S1, S2, ... S... n The switching on and off of the circuit controls the capacitance of the intervention system, thereby changing the self-resonant frequency. For example... Figure 4 As shown, the specific control method is as follows:

[0046] 1) In the initial state, connect the set capacitor.

[0047] In the initial state, S1 and S2 can be set to conduct, and capacitors C01 and C02 can be connected, i.e., C = C01 + C02, and this capacitance value can be used as the theoretical design value.

[0048] 2) Detect the self-resonant frequency.

[0049] Based on the self-resonance state of the capacitor and the inductance of the coupling coil, the self-resonance frequency in the current state is calculated by the zero-crossing detection circuit.

[0050] 3) Adjust the capacitor according to the self-resonant frequency.

[0051] To determine if the current self-resonant frequency matches the operating frequency, according to national standards, the system's operating frequency is 85kHz. If the current self-resonant frequency does not match the operating frequency, control other channels (S3~S4). n The capacitor is controlled as follows.

[0052] If the current self-resonant frequency is inconsistent with the operating frequency, you can first turn on the MOSFET and connect the capacitor to increase the capacitance value. If, after connecting the capacitor, the self-resonant frequency moves closer to the operating frequency, continue connecting the capacitor until the self-resonant frequency reaches the operating frequency. (Those skilled in the art should understand that when the self-resonant frequency reaches the set range of the operating frequency, it can be considered that the self-resonant frequency has reached the operating frequency.) If, after connecting the capacitor, the self-resonant frequency moves away from the operating frequency, turn off the MOSFET and disconnect the capacitor until the self-resonant frequency reaches the operating frequency. Alternatively, you can choose to first disconnect the MOSFET and disconnect the capacitor to observe the change in the self-resonant frequency.

[0053] 4) The self-resonant frequency is kept consistent with the operating frequency by adjusting the capacitance value of the access system in real time.

[0054] In addition to this embodiment, individual capacitors (C01, C02, ... C0) n ) and MOSFETs (Q1, Q2, ... Q n Several (two or more) individual branches are connected in parallel to form a single branch, and several single branches are connected in series to form a capacitor circuit. The capacitance value connected to the system is controlled by turning the MOSFET on and off.

[0055] This invention utilizes the switching in and out of the capacitor to adapt to changes in inductance, thereby achieving the self-resonant frequency at the operating frequency. Individual capacitors in this invention are insensitive to temperature changes, allowing for the use of lower-cost capacitors. Other connection methods, such as series-parallel (SP), parallel-series (PS), parallel-parallel (PP), and composite resonance, are also applicable, mitigating the impact of the capacitor on the overall system. Composite resonance can improve voltage and current stress, increase the system's soft-switching range, and reduce losses.

[0056] Vehicle Example:

[0057] The present invention provides a vehicle that uses the vehicle-side wireless charging module in the above system. The vehicle-side wireless charging module has been clearly described in the system embodiments and will not be repeated here.

Claims

1. A wireless charging dynamic frequency adjustment system, comprising a ground-end wireless charging module and a vehicle-end wireless charging module, wherein the vehicle-end wireless charging module includes a vehicle coupling circuit connected to a rectifier module, characterized in that, The vehicle coupling circuit includes a vehicle coupling coil and an adjustable capacitor circuit for connecting a resonant capacitor to the vehicle-end coupling circuit. The adjustable capacitor circuit includes several resonant capacitors. The vehicle-end wireless charging module also includes a controller, which is connected to the adjustable capacitor circuit to control the resonant capacitor to switch into or out of the vehicle coupling circuit, thereby realizing the adjustment of the operating frequency of the vehicle coupling circuit. The controller also collects the operating frequency of the vehicle coupling circuit. When the operating frequency of the vehicle coupling circuit deviates from the set operating frequency, the adjustable capacitor circuit is controlled to switch in or out a set number of resonant capacitors; when the operating frequency of the vehicle coupling circuit is collected again, if the operating frequency of the vehicle coupling circuit moves closer to the set operating frequency, the number of resonant capacitors in the vehicle coupling circuit is adjusted according to the previous adjustment direction. If the operating frequency of the vehicle coupling circuit is far from the set operating frequency, the number of resonant capacitors in the vehicle coupling circuit is adjusted in the opposite direction to the previous adjustment until the operating frequency of the vehicle coupling circuit reaches the set operating frequency. The adjustment direction includes cutting in to increase the resonant capacitor in the vehicle coupling circuit and cutting out to decrease the resonant capacitor in the vehicle coupling circuit.

2. The wireless charging dynamic frequency adjustment system according to claim 1, characterized in that, It also includes a zero-crossing detection circuit connected to the controller, which collects the operating frequency of the vehicle coupling circuit.

3. The wireless charging dynamic frequency adjustment system according to claim 1, characterized in that, The adjustable capacitor circuit includes several capacitor branches connected in parallel. The adjustable capacitor circuit is connected in series with the vehicle coupling coil. Each capacitor branch includes a series-connected switching element and a resonant capacitor. The controller controls the connection of each switching element to control the on / off state of the corresponding capacitor branch, thereby realizing the switching on and off of the resonant capacitor.

4. The wireless charging dynamic frequency adjustment system according to claim 1, characterized in that, The ground-based wireless charging module includes a ground coupling circuit, which includes a ground coupling coil for coupling with the vehicle coupling coil and a capacitor adjustable circuit. The capacitor adjustable circuit includes several resonant capacitors. The ground-based wireless charging module also includes a controller, which is connected to the capacitor adjustable circuit to control the resonant capacitors to switch into or out of the ground coupling circuit, thereby realizing the adjustment of the operating frequency of the ground coupling coil. The controller also collects the operating frequency of the ground coupling circuit. When the operating frequency of the ground coupling circuit deviates from the set operating frequency, the adjustable capacitor circuit is controlled to switch in or out a set number of resonant capacitors. When the operating frequency of the ground coupling circuit is collected again, if the operating frequency of the ground coupling circuit is closer to the set operating frequency, the number of resonant capacitors in the ground coupling circuit is adjusted according to the previous adjustment direction; if the operating frequency of the ground coupling circuit is far from the set operating frequency, the number of resonant capacitors in the ground coupling circuit is adjusted in the opposite direction to the previous adjustment direction, until the operating frequency of the ground coupling circuit reaches the set operating frequency. The adjustment direction includes switching in to increase the resonant capacitors in the ground coupling circuit and switching out to decrease the resonant capacitors in the ground coupling circuit.

5. The wireless charging dynamic frequency adjustment system according to claim 4, characterized in that, The adjustable capacitor circuit includes several parallel capacitor branches, which are connected in series with the ground coupling coil. Each capacitor branch includes a series-connected switching element and a resonant capacitor. The controller controls each of the connected switching elements to control the on / off state of the corresponding capacitor branch, thereby enabling the resonant capacitor to be switched in and out.

6. The wireless charging dynamic frequency adjustment system according to claim 3 or 5, characterized in that, The switching element is a MOSFET.

7. A vehicle, characterized in that, The device includes a vehicle-side wireless charging module, which comprises a vehicle coupling circuit connected to a rectifier module. The vehicle coupling circuit includes a vehicle coupling coil and an adjustable capacitor circuit for connecting a resonant capacitor to the vehicle-side coupling circuit. The adjustable capacitor circuit includes several resonant capacitors. The vehicle-side wireless charging module also includes a controller connected to the adjustable capacitor circuit to control the resonant capacitors to switch into or out of the vehicle coupling circuit, thereby adjusting the operating frequency of the vehicle coupling circuit. The controller also collects the operating frequency of the vehicle coupling circuit. When the operating frequency of the vehicle coupling circuit deviates from the set operating frequency, the adjustable capacitor circuit is controlled to switch in or out a set number of resonant capacitors. When the operating frequency of the vehicle coupling circuit is collected again, if the operating frequency of the vehicle coupling circuit is closer to the set operating frequency, the number of resonant capacitors in the vehicle coupling circuit is adjusted according to the previous adjustment direction; if the operating frequency of the vehicle coupling circuit is far from the set operating frequency, the number of resonant capacitors in the vehicle coupling circuit is adjusted in the opposite direction to the previous adjustment direction, until the operating frequency of the vehicle coupling circuit reaches the set operating frequency. The adjustment direction includes switching in to increase the resonant capacitors in the vehicle coupling circuit and switching out to decrease the resonant capacitors in the vehicle coupling circuit.

8. The vehicle according to claim 7, characterized in that, It also includes a zero-crossing detection circuit connected to the controller, which collects the operating frequency of the vehicle's coupling circuit.

9. The vehicle according to claim 7, characterized in that, The adjustable capacitor circuit includes several capacitor branches connected in parallel. The adjustable capacitor circuit is connected in series with the vehicle coupling coil. Each capacitor branch includes a series-connected switching element and a resonant capacitor. The controller controls the connection of each switching element to control the on / off state of the corresponding capacitor branch, thereby realizing the switching on and off of the resonant capacitor.

10. The vehicle according to claim 9, characterized in that, The switching element is a MOSFET.

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