A control method and device of a wireless charging system and the wireless charging system

Abstract

This invention provides a control method, apparatus, and wireless charging system for a wireless charging system. The method includes: setting the wireless charging system to operate at its resonant frequency; controlling the Ubus voltage within a first predetermined voltage threshold based on the AC / DC and DC / DC modules in the ground-side unit; obtaining a first voltage and a first current of the ground-side unit; setting a second voltage protection threshold and a second current protection threshold for the vehicle-side unit based on the first voltage and the first current, thereby obtaining the first voltage protection threshold and the first current protection threshold for the ground-side unit; detecting the first voltage and the first current, determining whether the first voltage exceeds the first voltage protection threshold and / or whether the first current exceeds the first current protection threshold, obtaining a first determination result, and sending it to a loop control module; and controlling the wireless charging system based on the first determination result. This solves the problems of long interaction time between the ground-side and vehicle-side wireless charging systems and poor charging current / voltage control performance.

Description

Technical Field

[0001] This invention relates to the field of wireless charging technology, and in particular to a control method, device, and wireless charging system for a wireless charging system. Background Technology

[0002] Wireless charging technology is convenient to operate and has a low device loss rate, making it a popular new charging technology in the market. Currently, some electric vehicles also utilize wireless charging technology.

[0003] During the charging process of electric vehicles, wireless communication technology enables interaction between the ground terminal and the vehicle, thereby controlling the charging current / voltage. However, wireless communication technology has a certain data transmission and interaction time, resulting in a long interaction time between the ground terminal and the vehicle terminal, and poor control of charging current / voltage. Summary of the Invention

[0004] This application provides a control method, device, and wireless charging system for addressing the technical problems of long interaction time between the ground end and vehicle end in existing wireless charging technologies, and poor control effect of charging current / voltage.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a control method for a wireless charging system. The method is applied to a wireless charging system comprising a ground-side unit, a vehicle-side unit, a secondary-side overvoltage / overcurrent protection module, a loop control module, and a battery. The method comprises: setting a first MOS switch, a second MOS switch, a third MOS switch, and a fourth MOS switch in the ground-side unit to a resonant point; controlling the Ubus voltage within a first predetermined voltage threshold based on the AC / DC module and DC / DC module in the ground-side unit; obtaining a first voltage and a first current of the ground-side unit; setting a second voltage protection threshold and a second current protection threshold for the vehicle-side unit based on the first voltage and the first current, while simultaneously obtaining the first voltage protection threshold and the first current protection threshold of the ground-side unit; detecting the first voltage and the first current, determining whether the first voltage exceeds the first voltage protection threshold and / or whether the first current exceeds the first current protection threshold, obtaining a first determination result, and sending it to the loop control module; and the loop control module controlling the first MOS switch, the second MOS switch, the third MOS switch, and the fourth MOS switch according to the first determination result to protect the wireless charging system.

[0007] A second aspect of the present invention provides a wireless charging system, the system comprising: a ground-side unit for providing high-frequency alternating current; a vehicle-side unit for receiving the high-frequency alternating current from the ground-side unit and converting it into direct current; a secondary-side overvoltage / overcurrent protection module for setting voltage protection thresholds and current protection thresholds for the vehicle-side unit and the ground-side unit based on the high-frequency alternating current, determining whether the voltage of the ground-side unit exceeds the voltage protection threshold and / or whether the current of the ground-side unit exceeds the current protection threshold, and obtaining a first determination result; a loop control module for controlling a first MOS switch, a second MOS switch, a third MOS switch, and a fourth MOS switch according to the first determination result to protect the wireless charging system; and a battery for receiving the direct current converted and output by the vehicle-side unit for charging.

[0008] A third aspect of the present invention provides a control device for a wireless charging system, comprising: a processor coupled to a memory for storing a program, wherein when the program is executed by the processor, the device performs the steps of the method as described in the first aspect.

[0009] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method as described in the first aspect.

[0010] The beneficial effects of this invention are:

[0011] The above-described solution, provided in this application, involves setting the wireless charging system based on SS topology to operate at a resonant point. The first, second, third, and fourth MOS switches in the ground-side unit are positioned at the resonant point. Then, based on the AC / DC and DC / DC modules in the ground-side unit, a lower Ubus voltage is controlled to output. Next, based on the effective voltage and current of the ground-side unit, a second voltage protection threshold and a second current protection threshold are set for the vehicle-side unit. Based on Kirchhoff's law formula at the resonant frequency, the first voltage protection threshold and the first current protection threshold of the ground-side unit are simultaneously obtained. Finally, the first voltage and the first current at the ground-side unit are detected to determine whether they exceed the first voltage protection threshold and / or the first current protection threshold, thereby protecting the wireless charging system. This application is based on SS topology wireless charging technology. According to Kirchhoff's second law formula at the resonant frequency point, the voltage and current of the vehicle's secondary side can be obtained by detecting the voltage and current of the primary side at the ground end. There is no need to transmit the vehicle's voltage and current information through wireless communication technology, so overcurrent and overvoltage protection can be performed for vehicle-side wireless charging. This saves the data interaction time of wireless communication, avoids the runaway of charging voltage / current due to wireless communication abnormalities, improves the reliability of the wireless charging system, and achieves the technical effect of improving the control effect of wireless charging current / voltage. Attached Figure Description

[0012] Figure 1 A flowchart illustrating the control method of the wireless charging system provided in an embodiment of the present invention;

[0013] Figure 2 This is a schematic diagram of the structure of an SS topology wireless charging system in the prior art;

[0014] Figure 3 This is a schematic diagram of a wireless charging system structure provided in an embodiment of the present invention;

[0015] Figure 4 This is a schematic diagram of the structure of an exemplary control device according to an embodiment of the present invention.

[0016] Explanation of reference numerals in the attached figures:

[0017] 11-Ground end unit; 12-Vehicle end unit; 13-Secondary side overvoltage / overcurrent protection module; 14-Loop control module; 15-Battery; 300-Control device; 301-Memory; 302-Processor; 303-Communication interface; 304-Bus architecture. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] This invention addresses the problems of long interaction time between the ground end and the vehicle end in wireless charging and poor control of charging current / voltage in the prior art, and provides a control method, device and wireless charging system for a wireless charging system.

[0020] Wireless charging technology is convenient to operate and has a low device loss rate. It is a new type of charging technology suitable for charging various electronic devices and is widely popular in the market. Electric vehicles are favored by consumers in the automotive market due to their advantages of zero emissions, environmental friendliness, and energy saving. Currently, some electric vehicles and charging stations also use wired charging technology.

[0021] During wireless charging of electric vehicles, it is crucial to ensure stable voltage and current charging to guarantee charging safety and battery lifespan. Specifically, this is achieved by detecting the charging voltage and current at the vehicle's secondary charging terminal and then transmitting this information to the ground terminal's primary charging terminal via wireless communication. This interaction between the ground and vehicle terminals allows the ground terminal to control its output current / voltage based on the vehicle's charging voltage and current, thus achieving stable charging voltage / current control. However, wireless communication technology has a significant data transmission and interaction time, typically reaching hundreds of milliseconds. Furthermore, if the wireless communication system malfunctions, the vehicle and ground terminals cannot communicate, leading to a loss of control in the wireless charging system. Therefore, existing technologies suffer from long wireless communication interaction times between the ground and vehicle terminals, resulting in poor charging current / voltage control.

[0022] Example 1

[0023] like Figure 1 As shown, this application provides a control method for a wireless charging system. The method is applied to a wireless charging system including a ground unit, a vehicle unit, a secondary overvoltage / overcurrent protection module, a loop control module, and a battery. The method described in this application includes:

[0024] S100: Set the first MOS switch, second MOS switch, third MOS switch and fourth MOS switch in the ground terminal unit to the resonant point;

[0025] Specifically, the method provided in this application embodiment is applied to a wireless charging system for an electric vehicle. In the wireless charging system for an electric vehicle, the atmospheric gap between the primary and secondary coils will generate leakage inductance, thereby reducing the charging efficiency of wireless charging.

[0026] Therefore, in order to compensate for leakage inductance, existing technologies have designed four compensation topologies based on the compensation method of the primary and secondary sides: serial-to-serial (SS), serial-to-parallel (SP), parallel-to-serial (PS), and parallel-to-parallel (PP).

[0027] In the method provided in this application embodiment, the wireless charging system for electric vehicles adopts an SS topology, such as... Figure 2 As shown, in the SS topology, S1 to S4 are four power MOSFETs at the ground end, which can be used to regulate power and control circuit switches at various points. D1 to D4 are rectifier diodes at the vehicle end, and L1 and L2 are the self-inductances of the transmitting and receiving coils, respectively. C1 and C2 are compensation capacitors. The voltage between A and B is the ground end bridge arm voltage U1. The voltage between ab and B is the vehicle end bridge arm voltage U2. M is the mutual inductance coefficient between the primary and secondary sides, M = k * sqrt(L1 * L2). The turns ratio n of the primary and secondary coils is assumed to be n = 1.

[0028] In a traditional SS topology wireless charging system, the current and voltage signals of the secondary side are transmitted to the primary side via wireless communication. The primary side then controls and adjusts four MOS switches based on the current and voltage of the secondary side to achieve constant voltage / continuous current charging.

[0029] Based on the SS topology, and using Kirchhoff's second law, the KVL formula is written as follows:

[0030]

[0031] When the wireless charging system operates at the resonant frequency... Then we have:

[0032]

[0033] Where L1 is the self-inductance of the receiving coil; C1 is the compensation capacitor; M is the mutual inductance coefficient; U1 is the primary voltage; U2 is the secondary voltage; I1 is the primary current; and I2 is the secondary current.

[0034] As can be seen from formula (1), when the wireless charging system operates at the resonant frequency, the primary and secondary sides are fixed, and M is fixed, the increase or decrease of the primary side voltage directly reflects the increase or decrease of the secondary side charging current; the increase or decrease of the primary side current directly reflects the increase or decrease of the secondary side voltage.

[0035] Based on the above analysis, the embodiments of this application firstly set the first MOS switch, the second MOS switch, the third MOS switch and the fourth MOS switch in the ground terminal unit to the resonant point, so that the wireless charging system operates at the resonant frequency.

[0036] S200: Based on the AC / DC module and DC / DC module in the ground terminal unit, control the Ubus voltage to be within a first predetermined voltage threshold.

[0037] Figure 3A schematic diagram of a possible structure of the wireless charging system to which the method of the embodiments of this application is applied is shown. Specifically, as Figure 3 As shown, based on the AC / DC module and DC / DC module in the ground unit, the Ubus outputs a low voltage, and the voltage is maintained within a first predetermined voltage threshold until the wireless charging system stabilizes.

[0038] S300: Obtain the first voltage and first current of the ground terminal unit;

[0039] The effective voltage and effective current within the ground terminal unit are detected and acquired, and the effective voltage and effective current within the ground terminal unit are used as the first voltage and the first current.

[0040] S400: Set the second voltage protection threshold and the second current protection threshold of the vehicle-end unit according to the first voltage and the first current, and simultaneously obtain the first voltage protection threshold and the first current protection threshold of the ground-end unit.

[0041] Specifically, based on the safety requirements of vehicle-side charging and batteries, a safe voltage threshold and a safe current threshold for vehicle-side charging are set as the second voltage protection threshold and the second current protection threshold for the vehicle-side unit. Simultaneously, based on the above formula (1), the first voltage protection threshold and the first current protection threshold for the ground-side unit are correspondingly obtained.

[0042] Step S400 in the method provided in this application includes:

[0043] S410: Obtain the first mutual inductance coefficient based on the first voltage and the first current;

[0044] S420: Set the second voltage protection threshold and the second current protection threshold of the vehicle-end unit;

[0045] S430: Based on the second voltage protection threshold, the second current protection threshold, and the first mutual inductance coefficient, obtain the first voltage protection threshold and the first current protection threshold of the ground terminal unit.

[0046] Specifically, when the Ubus output voltage in the wireless charging system is low until the system stabilizes, the first mutual inductance coefficient M of the wireless charging system can be calculated based on the effective values ​​of the first voltage and the first current obtained, according to formula (1).

[0047] Then, based on the safety requirements of electric vehicle charging, the second voltage protection threshold U2_th and the second current protection threshold I2_th of the vehicle-side unit are set.

[0048] After obtaining the second voltage protection threshold U2_th and the second current protection threshold I2_th, according to the first mutual inductance coefficient M, we have:

[0049]

[0050] In this way, the first voltage protection threshold U1_th and the first current protection threshold I1_th of the ground terminal unit can be calculated.

[0051] Furthermore, when the second current of the vehicle-end unit increases beyond the second current protection threshold, the first voltage of the ground-end unit increases beyond the first voltage protection threshold. When the second voltage of the vehicle-end unit increases beyond the second voltage protection threshold, the first current of the ground-end unit increases beyond the first current protection threshold.

[0052] S500: Detect the first voltage and the first current, determine whether the first voltage exceeds the first voltage protection threshold and / or whether the first current exceeds the first current protection threshold, obtain a first determination result and send it to the loop control module;

[0053] Specifically, based on the above principle, by directly detecting the first voltage and first current of the ground-side unit at the ground-side unit, the second voltage and second current of the vehicle-side unit can be obtained. Furthermore, by determining whether the first voltage exceeds the first voltage protection threshold and / or whether the first current exceeds the first current protection threshold, it is possible to simultaneously determine whether the second voltage of the vehicle-side unit and the battery exceeds the second voltage protection threshold and / or whether the second current exceeds the second current protection threshold, thus completing the overvoltage / overcurrent monitoring and protection for electric vehicle charging.

[0054] After determining whether the first voltage of the ground unit exceeds the first voltage protection threshold and / or whether the first current exceeds the first current protection threshold, a first determination result is obtained. This first determination result is sent to the loop control module of the wireless charging system, which can then determine whether protection of the wireless charging system is required based on the first determination result.

[0055] The loop control module is directly connected to the ground unit, eliminating the need for wireless communication technology. It directly acquires the first voltage and first current for judgment, saving the wireless communication interaction time between the ground unit and the vehicle unit and improving the voltage / current control effect.

[0056] S600: The loop control module controls the first MOS switch, the second MOS switch, the third MOS switch and the fourth MOS switch according to the first judgment result to protect the wireless charging system.

[0057] Specifically, based on the first judgment result, the loop control module controls the switching states of the first MOS switch, the second MOS switch, the third MOS switch and the fourth MOS switch to make the first voltage between the ground end unit AB 0. Based on formula (1), the second current of the vehicle end unit is made 0, blocking the energy output from the primary side to the secondary side, thereby realizing the protection of the wireless charging system in the event of overvoltage / current.

[0058] In this embodiment of the application, step S600 includes step S610, which includes:

[0059] S611: When the first judgment result is that the first voltage exceeds the first voltage protection threshold and / or the first current exceeds the first current protection threshold, the loop control module obtains the first reminder information;

[0060] S612: According to the first reminder information, close the third MOS switch and the fourth MOS switch, and disconnect the first MOS switch and the second MOS switch.

[0061] Specifically, when the first judgment result is that the first voltage exceeds the first voltage protection threshold and / or the first current exceeds the first current protection threshold, then according to formula (1), the second current exceeds the second current protection threshold and / or the second voltage exceeds the second voltage protection threshold, the vehicle end unit experiences overvoltage / overcurrent conditions, and the loop control module obtains the first reminder information;

[0062] Furthermore, based on the first reminder information, the loop control module closes the third and fourth MOS switches and disconnects the first and second MOS switches. At this time, the first voltage between the ground end units A and B is 0. According to formula (1), the second current of the vehicle end unit quickly drops to 0, blocking the energy output from the primary side to the secondary side.

[0063] The method provided in this application embodiment further includes step S700, which includes:

[0064] S710: Detect the second current and the second voltage, and transmit them to the ground terminal unit via wireless communication;

[0065] S720: The ground terminal unit calculates and outputs a control quantity based on the second current and the second voltage;

[0066] S730: The ground terminal unit adjusts the Ubus voltage of the ground terminal unit according to the control quantity.

[0067] Specifically, based on the aforementioned method, overvoltage / overcurrent situations can be protected during secondary-side charging, and the time for wireless communication interaction is eliminated, resulting in better control. However, in order to maintain stable voltage and current charging, it is also necessary to detect and control the second current and second voltage of the secondary side.

[0068] Specifically, during wireless charging, the second current and second voltage of the secondary side are detected and transmitted to the primary side on the ground based on existing wireless communication technology. The primary side calculates the second current and second voltage and outputs control quantity information for controlling the output voltage and power supply of the primary side.

[0069] Based on this control information, the ground unit adjusts the Ubus voltage of the ground unit.

[0070] Based on the above method, not only can overvoltage / overcurrent conditions be monitored during secondary charging to protect the wireless charging system, but also stable voltage and current charging can be maintained, maximizing the control effect and stability of the wireless charging system.

[0071] Example 2

[0072] This embodiment provides a control method for a wireless charging system. The method is applied to a wireless charging system, which includes a ground-end unit, a vehicle-end unit, a secondary-side overvoltage / overcurrent protection module, a loop control module, and a battery. The method in this embodiment is the same as the method in Embodiment 1 in other parts, except for step S600, which includes step S620. Step S620 includes:

[0073] S621: When the first judgment result is that the first voltage exceeds the first voltage protection threshold and / or the first current exceeds the first current protection threshold, the loop control module obtains the second reminder information;

[0074] S622: According to the second reminder information, close the first MOS switch and the second MOS switch, and open the third MOS switch and the fourth MOS switch.

[0075] Specifically, when the first judgment result is that the first voltage exceeds the first voltage protection threshold and / or the first current exceeds the first current protection threshold, then according to formula (1), the second current exceeds the second current protection threshold and / or the second voltage exceeds the second voltage protection threshold, the vehicle end unit experiences overvoltage / overcurrent conditions, and the loop control module obtains the second reminder information;

[0076] Furthermore, based on the second reminder information, the loop control module closes the first and second MOS switches and disconnects the third and fourth MOS switches. At this time, the first voltage between the ground terminal units A and B is 0. According to formula (1), the second current of the vehicle terminal unit quickly drops to 0, blocking the energy output from the primary side to the secondary side.

[0077] In summary, this application, based on SS topology wireless charging technology, utilizes Kirchhoff's second law formula at the resonant frequency point. By detecting the voltage and current of the primary side at the ground end, the voltage and current of the secondary side at the vehicle end can be determined. This eliminates the need to transmit vehicle-side voltage and current information via wireless communication technology, enabling overcurrent and overvoltage protection for vehicle-side wireless charging. It also saves data interaction time in wireless communication, avoids voltage / current runaway caused by wireless communication anomalies, improves the reliability of the wireless charging system, and achieves the technical effect of enhancing wireless charging current / voltage control.

[0078] Example 3

[0079] Based on the same inventive concept as the control method of a wireless charging system in the foregoing embodiments, such as Figure 3 As shown, this application provides a wireless charging system, the system comprising:

[0080] Ground terminal unit 11, the ground terminal unit 11 being used to provide high-frequency alternating current;

[0081] Vehicle-end unit 12, which receives the high-frequency alternating current from the ground-end unit 11 and converts it into direct current;

[0082] The secondary-side overvoltage / overcurrent protection module 13 sets the voltage protection threshold and current protection threshold of the vehicle-end unit 12 and the ground-end unit 11 according to the high-frequency AC current, and determines whether the voltage of the ground-end unit 11 exceeds the voltage protection threshold and / or whether the current of the ground-end unit 11 exceeds the current protection threshold, thereby obtaining a first judgment result.

[0083] The loop control module 14 controls the first MOS switch, the second MOS switch, the third MOS switch and the fourth MOS switch according to the first judgment result to protect the wireless charging system.

[0084] Battery 15, which receives the DC current converted and output by the vehicle-end unit 12 for charging.

[0085] As mentioned above, the ground unit 11 is used to output high-frequency alternating current, which is wirelessly charged through the output coil and receiving coil in the wireless charging technology and through the SS topology compensation test. The vehicle unit 12 receives the energy emitted by the ground unit 11 and converts it into direct current to charge the battery 15.

[0086] Based on the method described in Embodiment 1, the ground unit 11 can detect and collect its internal voltage and current during wireless charging, and transmit them to the secondary overvoltage / overcurrent protection module 13 to determine whether the voltage of the ground unit 11 exceeds the voltage protection threshold of the ground unit 11 and / or whether the current of the ground unit 11 exceeds the current protection threshold of the ground unit 11, and obtain a first judgment result. This allows direct determination of whether the vehicle unit 12 has experienced overvoltage / overcurrent, saving the time of wireless communication data interaction and resulting in better control of the wireless charging system.

[0087] Based on the first judgment result of the secondary overvoltage / overcurrent protection module 13, the loop control module 14 controls the first MOS switch, the second MOS switch, the third MOS switch and the fourth MOS switch according to the method in Embodiment 1 or Embodiment 2 to protect the wireless charging system, prevent the wireless charging system from becoming unstable and improve the service life of the battery 15.

[0088] Example 4

[0089] Based on the same inventive concept as the control method of a wireless charging system in the foregoing embodiments, this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method as described in Embodiment 1.

[0090] Exemplary control device

[0091] The following is for reference. Figure 4 The control device of the present invention will be described below.

[0092] Based on the same inventive concept as the control method of a wireless charging system in the foregoing embodiments, this application also provides a control device for a wireless charging system, including: a processor coupled to a memory for storing a program, wherein when the program is executed by the processor, the device performs the steps of the method described in Embodiment 1.

[0093] The control device 300 includes a processor 302, a communication interface 303, and a memory 301. Optionally, the control device 300 may also include a bus architecture 304. The communication interface 303, processor 302, and memory 301 can be interconnected via the bus architecture 304; the bus architecture 304 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus architecture 304 can be divided into an address bus, a data bus, and a control bus, etc. For ease of representation, Figure 4 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0094] Processor 302 may be a CPU, microprocessor, ASIC, or one or more integrated circuits used to control the execution of programs according to the present application.

[0095] Communication interface 303 uses any transceiver-like device for communicating with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area network (WLAN), wired access network, etc.

[0096] Memory 301 can be ROM or other types of static storage devices capable of storing static information and instructions, RAM or other types of dynamic storage devices capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto. Memory can exist independently and be connected to the processor via bus architecture 304. Memory can also be integrated with the processor.

[0097] The memory 301 stores computer execution instructions for implementing the scheme of this application, and the processor 302 controls the execution. The processor 302 executes the computer execution instructions stored in the memory 301, thereby implementing the control method of the wireless charging system provided in the above embodiments of this application.

[0098] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive (SSD)).

[0099] The above describes the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also within the scope of protection of the present invention.

Claims

1. A control method for a wireless charging system, characterized in that, The method is applied to a wireless charging system, the system comprising a ground-side unit, a vehicle-side unit, a secondary-side overvoltage / overcurrent protection module, a loop control module, and a battery, the method comprising: The first MOS switch, the second MOS switch, the third MOS switch, and the fourth MOS switch in the ground terminal unit are set at the resonant point; Based on the AC / DC module and DC / DC module in the ground terminal unit, the Ubus voltage is controlled to be within a first predetermined voltage threshold. Obtain the first voltage and first current of the ground terminal unit; The second voltage protection threshold and the second current protection threshold of the vehicle-end unit are set according to the first voltage and the first current, and the first voltage protection threshold and the first current protection threshold of the ground-end unit are obtained at the same time. The first voltage and the first current are detected, and it is determined whether the first voltage exceeds the first voltage protection threshold and / or whether the first current exceeds the first current protection threshold. A first determination result is obtained and sent to the loop control module. The loop control module controls the first MOS switch, the second MOS switch, the third MOS switch, and the fourth MOS switch according to the first judgment result to protect the wireless charging system; The formula for setting the second voltage protection threshold and the second current protection threshold of the vehicle-end unit based on the first voltage, the first current, and the first mutual inductance coefficient is as follows: At the resonant frequency At that time, there were: ； Where L1 is the self-inductance of the receiving coil; C1 is a compensation capacitor; M is the mutual inductance coefficient; U1 is the first voltage, and U2 is the second voltage; I1 is the first current, and I2 is the second current.

2. The method as described in claim 1, characterized in that, The loop control module, based on the first judgment result, controls the first MOS switch, the second MOS switch, the third MOS switch, and the fourth MOS switch to protect the wireless charging system, including: When the first determination result is that the first voltage exceeds the first voltage protection threshold and / or the first current exceeds the first current protection threshold, the loop control module obtains a first reminder message; According to the first reminder information, the third MOS switch and the fourth MOS switch are closed, and the first MOS switch and the second MOS switch are disconnected.

3. The method as described in claim 1, characterized in that, The loop control module, based on the first judgment result, controls the first MOS switch, the second MOS switch, the third MOS switch, and the fourth MOS switch to protect the wireless charging system, including: When the first determination result is that the first voltage exceeds the first voltage protection threshold and / or the first current exceeds the first current protection threshold, the loop control module obtains a second reminder message; According to the second reminder information, close the first MOS switch and the second MOS switch, and open the third MOS switch and the fourth MOS switch.

4. The method as described in claim 1, characterized in that, The step of setting the second voltage protection threshold and the second current protection threshold of the vehicle-end unit based on the first voltage and the first current, and simultaneously obtaining the first voltage protection threshold and the first current protection threshold of the ground-end unit, includes: The first mutual inductance coefficient is obtained based on the first voltage and the first current; Set the second voltage protection threshold and the second current protection threshold of the vehicle-end unit; The first voltage protection threshold and the first current protection threshold of the ground terminal unit are obtained based on the second voltage protection threshold, the second current protection threshold, and the first mutual inductance coefficient.

5. The method as described in claim 1, characterized in that, The method further includes: The second current and the second voltage are detected and transmitted to the ground terminal unit via wireless communication; The ground terminal unit calculates and outputs a control quantity based on the second current and the second voltage; The ground terminal unit adjusts the Ubus voltage of the ground terminal unit according to the control quantity.

6. A wireless charging system, the system comprising: A ground terminal unit, wherein the ground terminal unit is used to provide high-frequency alternating current; The vehicle-mounted unit receives the high-frequency alternating current from the ground-mounted unit and converts it into direct current; The secondary-side overvoltage / overcurrent protection module sets the voltage protection threshold and current protection threshold of the vehicle-end unit and the ground-end unit based on the high-frequency AC current, and determines whether the voltage of the ground-end unit exceeds the voltage protection threshold and / or whether the current of the ground-end unit exceeds the current protection threshold, thereby obtaining a first judgment result. A loop control module, which controls the first MOS switch, the second MOS switch, the third MOS switch and the fourth MOS switch according to the first judgment result, to protect the wireless charging system; The battery receives and is charged by the DC current converted and output by the vehicle-end unit; Based on the first judgment result of the secondary overvoltage / overcurrent protection module, the loop control module controls the first MOS switch, the second MOS switch, the third MOS switch and the fourth MOS switch according to the method described in any one of claims 1 to 5 to protect the wireless charging system.

7. A control device for a wireless charging system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor; characterized in that, When the processor executes the program, it implements the control method as described in any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the control method as described in any one of claims 1 to 5.

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