Wireless charging system, charging control method and device, charging equipment, vehicle, electronic equipment and storage medium

Abstract

The application relates to a wireless charging system, a charging control method and device, a charging equipment, a vehicle, an electronic equipment and a storage medium, the wireless charging system comprising: a primary side compensation circuit, wherein the primary side compensation circuit comprises a first inductor and a first capacitor; a first terminal of an output side of a primary side inverter circuit, the first inductor, the first capacitor, a primary side inductor and a second terminal of the output side of the primary side inverter circuit are sequentially connected; the primary side compensation circuit further comprises a switching module and a second capacitor, a first end of the switching module is connected between the first inductor and the first capacitor, a second end of the switching module is connected to a first end of the second capacitor, a second end of the second capacitor is connected between the primary side inductor and the second terminal of the output side of the primary side inverter circuit, and the switching module controls the wireless charging system to perform constant-current charging or constant-voltage charging; and a secondary side inductor, which forms mutual inductance with the primary side inductor. The application reduces the complexity, volume, weight and cost of the secondary side circuit, and is beneficial to the miniaturization design of the vehicle.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, specifically to a wireless charging system, charging control method, device, charging equipment, vehicle, electronic equipment, and storage medium. Background Technology

[0002] With the increasing demands for global energy structure transformation and environmental protection, electric vehicles (EVs) have rapidly developed as a clean energy transportation tool. However, traditional wired charging methods suffer from problems such as wear and tear from plugging and unplugging, contact sparks, safety hazards in rain and snow, and difficulties in standardizing charging interfaces, reducing the convenience and user experience of EV charging. Wireless power transfer technology, especially magnetically coupled wireless power transfer (MC-WPT) technology based on magnetic field coupling, has become a research hotspot in the field of EV charging due to its outstanding advantages such as no physical contact, automated charging process, strong environmental adaptability, and safety and reliability. The MC-WPT system achieves contactless power transfer through a high-frequency alternating magnetic field between the primary-side transmitting coil and the secondary-side receiving coil, featuring no mechanical wear, no risk of electric shock, concealable installation, and easy automated management. In recent years, with the increase in power device frequency, the improvement of magnetic material performance, and the continuous optimization of compensation topology, the transmission efficiency, power level, and transmission distance of the MC-WPT system have been significantly improved, laying a solid foundation for its commercial application in electric vehicles, rail transit, underwater equipment, and other fields.

[0003] However, most current bidirectional wireless charging systems for electric vehicles adopt a bilateral symmetrical structure, that is, compensation structures are set on both the primary and secondary sides. Setting compensation structures on the secondary side will lead to a complex and bulky vehicle circuit structure, which is not conducive to the miniaturization design of the vehicle, and will also increase the difficulty of maintenance. Summary of the Invention

[0004] One of the objectives of this application is to provide a wireless charging system, charging control method, device, charging equipment, vehicle, electronic equipment, and storage medium to solve the problem that existing wireless charging systems require compensation structures at both the charging equipment end and the vehicle end, which increases the complexity and size of the vehicle-side circuitry and is detrimental to the miniaturization design of vehicles.

[0005] In a first aspect, this application provides a wireless charging system, comprising: The primary-side inverter circuit has its input side connected to a DC power supply. The primary-side compensation circuit includes a first inductor and a first capacitor connected in series. The first inductor is connected to a first terminal on the output side of the primary-side inverter circuit, and the first capacitor is connected to the primary inductor. The primary inductor is connected to a second terminal on the output side of the primary-side inverter circuit. The primary-side compensation circuit also includes a switching module and a second capacitor. The first terminal of the second capacitor is connected between the first inductor and the first capacitor through the switching module, and the second terminal of the second capacitor is connected between the primary inductor and the second terminal on the output side of the primary-side inverter circuit. The switching module is used to control the wireless charging system to perform constant current charging or constant voltage charging. The secondary inductor has its first end connected to the first terminal of the input side of the secondary rectifier circuit, and its second end connected to the second terminal of the input side of the secondary rectifier circuit. The secondary inductor and the primary inductor form a mutual inductance.

[0006] In one possible implementation, the coupling coefficient between the primary inductor and the secondary inductor is greater than a preset value.

[0007] In one possible implementation, when the switch module is turned on, the wireless charging system performs constant current charging; when the switch module is turned off, the wireless charging system performs constant voltage charging.

[0008] In one possible implementation, the switching module includes: The first switching transistor has its source connected between the first inductor and the first capacitor, and its drain connected to the drain of the second switching transistor. The source of the second switching transistor is connected to the first terminal of the second capacitor.

[0009] In one possible implementation, the first inductor, the first capacitor, the primary-side inductor, and the second capacitor satisfy the following condition: ; ; Among them, L pr L is the first inductor. p For the primary-side inductance, C p Let C be the first capacitor, k be the coupling coefficient of the wireless charging system, and C be the first capacitor. pr ω is the second capacitor, and ω is the operating angular frequency of the wireless charging system.

[0010] Secondly, this application provides a charging control method applied to the wireless charging system described in any one of the first aspects above, the charging control method comprising: After charging begins, the wireless charging system is controlled to perform constant current charging; Determine whether the constant voltage charging condition is met based on the charging power of the wireless charging system. When the constant voltage charging condition is met, the wireless charging system is controlled to switch to constant voltage charging.

[0011] In one possible implementation, controlling the wireless charging system to perform constant current charging includes: controlling the switch module to turn on; controlling the wireless charging system to switch to constant voltage charging includes: controlling the switch module to turn off.

[0012] In one possible implementation, the wireless charging system satisfies the following condition when performing constant current charging: ; Among them, X Lp X is the impedance of the primary inductor. Cp X is the impedance of the first capacitor. Cpr X is the impedance of the second capacitor. Lpr Let be the impedance of the first inductor.

[0013] In one possible implementation, determining whether the constant voltage charging condition is met based on the charging power of the wireless charging system includes: Determine whether the charging power has reached a preset power value; wherein, the preset power value is the power value corresponding to the constant current charging power and constant voltage charging power of the wireless charging system being equal; If so, the constant voltage charging condition is met.

[0014] In one possible implementation, the primary-side inverter circuit includes a first inverter bridge and a second inverter bridge, and controls the wireless charging system to switch to constant voltage charging when the constant voltage charging condition is met, including: The phase shift angle between the first inverter bridge and the second inverter bridge is gradually reduced from 180° to 0°. Control the wireless charging system to switch from constant current charging to constant voltage charging; The phase shift angle between the first inverter bridge and the second inverter bridge is controlled to gradually increase from 0° to 180°.

[0015] In one possible implementation, when the phase shift angle between the first inverter bridge and the second inverter bridge is 0°, the following condition is satisfied: ; Among them, X Lp X is the impedance of the primary inductor. Cp X is the impedance of the first capacitor. Cpr X is the impedance of the second capacitor. Lpr X is the impedance of the first inductor. LsThe impedance of the secondary inductor is given.

[0016] Thirdly, this application provides a charging control device for implementing the charging control method described in any one of the second aspects above, the charging control device comprising: The first control module is used to control the wireless charging system to perform constant current charging after charging begins. The judgment module is used to determine whether the constant voltage charging condition is met based on the charging power of the wireless charging system. The second control module is used to control the wireless charging system to switch to constant voltage charging when the constant voltage charging condition is met.

[0017] Fourthly, this application provides a charging device, comprising: The primary-side compensation circuit includes a first inductor and a first capacitor connected in series. The first inductor is connected to a first terminal on the output side of the primary-side inverter circuit, and the first capacitor is connected to the primary-side inductor. The primary-side inductor is connected to a second terminal on the output side of the primary-side inverter circuit. The primary-side compensation circuit also includes a switching module and a second capacitor. The first terminal of the second capacitor is connected between the first inductor and the first capacitor through the switching module, and the second terminal of the second capacitor is connected between the primary-side inductor and the second terminal on the output side of the primary-side inverter circuit. The switching module is used to control the wireless charging system to perform constant current charging or constant voltage charging.

[0018] Fifthly, this application provides a vehicle, comprising: The secondary inductor has its first end connected to the first terminal of the input side of the secondary rectifier circuit, and its second end connected to the second terminal of the input side of the secondary rectifier circuit. When the vehicle is used in conjunction with the charging equipment described in the fourth aspect above, the secondary inductor and the primary inductor form a mutual inductance.

[0019] In a sixth aspect, this application provides an electronic device, comprising: a processor and a memory, wherein the processor is configured to execute a charging control program stored in the memory to implement the charging control method of any of the second aspects described above.

[0020] In a seventh aspect, this application provides a storage medium storing one or more programs that can be executed by one or more processors to implement the charging control method of any of the second aspects above.

[0021] The beneficial effects of this application are as follows: the secondary side only contains a rectifier circuit and a secondary inductor, without any resonant compensation components or switching devices, which greatly reduces the complexity, size, weight and cost of the secondary side circuit. This is beneficial for installing the secondary side circuit in limited spaces such as electric vehicle chassis, thus facilitating the miniaturization design of the vehicle. Since the secondary side does not have resonant compensation components and switching devices, it reduces the vehicle's failure points and improves the vehicle's reliability and maintainability. Attached Figure Description

[0022] Figure 1 This application provides a structural diagram of a wireless charging system according to an embodiment. Figure 2 This diagram illustrates the structure of a switch module provided in an embodiment of this application. Figure 3 This document shows a flowchart of a charging control method provided in an embodiment of this application. Figure 4 This diagram illustrates a circuit structure for constant current charging according to an embodiment of this application. Figure 5 This diagram illustrates a circuit structure for constant voltage charging according to an embodiment of this application. Figure 6 This diagram shows an equivalent model of the leakage inductance of an SN-type compensation circuit provided in an embodiment of this application. Figure 7 The simulated output voltage and simulated output current curves of the LCC-N type compensation circuit of the wireless charging system provided in the embodiments of this application are shown. Figure 8 The simulated output voltage and simulated output current curves of the SN-type compensation circuit of the wireless charging system provided in the embodiments of this application are shown. Figure 9 This application provides a graph showing the change of charging power over time during constant current charging and constant voltage charging, as illustrated in the embodiments of this application. Figure 10 This application provides an embodiment of the charging voltage variation over time during constant current charging and constant voltage charging. Figure 11 This application provides an embodiment of the curves showing the change of charging current over time during constant current charging and constant voltage charging. Figure 12 This paper shows the timing diagram of the control signals of the phase angle reduction process switches S1~S5 provided in an embodiment of this application; Figure 13 This paper shows the timing diagram of the control signals of switches S1 to S5 for the phase shift angle increase process provided in an embodiment of this application; Figure 14 A flowchart illustrating the turn-off process of the switch module provided in an embodiment of this application is shown; Figure 15This diagram shows a structural block diagram of the charging control device provided in an embodiment of this application; Figure 16 This diagram illustrates the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0023] The embodiments of this application will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be understood that the preferred embodiments are only for illustrating this application and are not intended to limit the scope of protection of this application.

[0024] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0025] To facilitate understanding of the embodiments of this application, the following will provide further explanation and description with reference to the accompanying drawings and specific embodiments. These embodiments do not constitute a limitation on the embodiments of this application.

[0026] Example 1 Since most current electric vehicle bidirectional wireless charging systems adopt a bilateral symmetrical structure, that is, compensation structures are set on both the primary and secondary sides, setting compensation structures on the secondary side will lead to a complex and bulky vehicle circuit structure, which is not conducive to the miniaturization design of the vehicle and increases the maintenance difficulty. In order to solve the above problems, this embodiment provides a wireless charging system.

[0027] refer to Figure 1 , Figure 1 A structural diagram of a wireless charging system is provided for an embodiment of this application. For example... Figure 1 As shown, the wireless charging system provided in this application embodiment includes the following parts: Primary-side inverter circuit 1 has a DC power supply connected to its input side, and the output voltage of the DC power supply is U. DC The primary-side inverter circuit 1 includes two inverter bridges. The first inverter bridge includes two MOSFET switches (metal-oxide-semiconductor field-effect transistors) S1 and S2, and two MOSFET switches S3 and S4. The effective value of the output AC voltage of the primary-side inverter circuit 1 is Up.

[0028] The primary-side compensation circuit 2 includes a first inductor Lpr, a first capacitor Cp, and a primary-side inductor Lp connected in series. The first inductor Lpr is connected to the first terminal of the output side of the primary-side inverter circuit 1, and the primary-side inductor Lp is connected to the second terminal of the output side of the primary-side inverter circuit 1. The primary-side compensation circuit also includes a switch module S5 and a second capacitor Cpr. The first terminal of the second capacitor Cpr is connected between the first inductor Lpr and the first capacitor Cp through the switch module S5, and the second terminal of the second capacitor Cpr is connected between the primary inductor Lp and the second terminal of the output side of the primary-side inverter circuit 1. The switch module is used to control the wireless charging system to perform constant current charging or constant voltage charging. The first inductor Lpr is a series resonant inductor, the first capacitor Cp is a series resonant capacitor, and the second capacitor Cpr is a parallel resonant capacitor.

[0029] The secondary inductor Ls has its first end connected to the first terminal of the input side of the secondary rectifier circuit 3, and its second end connected to the second terminal of the input side of the secondary rectifier circuit 3. The secondary inductor Ls and the primary inductor Lp form a mutual inductance M. The primary inductor Lp is the self-inductance value of the primary transmitting coil, which is located at the charging device end. The secondary inductor Ls is the self-inductance value of the secondary receiving coil, which is located at the vehicle end. During charging, a high-frequency alternating magnetic field is formed between the primary inductor Lp at the charging device end and the secondary inductor Ls at the vehicle end, thereby realizing contactless transmission of electrical energy.

[0030] The secondary rectifier circuit 3 includes uncontrolled diodes D1-D4, and the output side of the secondary rectifier circuit 3 is connected to the load R. L Load R L The voltage across the terminals is U L DC bus capacitors C are also installed on the two DC buses on the output side of the secondary rectifier circuit 3. o In this embodiment, the load R L It can be used as a battery for electric vehicles.

[0031] Up is the effective value of the AC voltage output from the bridge port of the primary-side inverter circuit, and Us is the effective value of the AC voltage input to the secondary-side rectifier circuit.

[0032] This embodiment provides a wireless charging system. First, the secondary side only includes a rectifier circuit and a secondary inductor, without any resonant compensation components or switching devices. This greatly reduces the complexity, size, weight, and cost of the secondary side circuit, making it easier to install in limited spaces such as electric vehicle chassis, thus facilitating vehicle miniaturization. Second, since the secondary side does not have resonant compensation components or switching devices, it reduces the vehicle's potential failure points, improving reliability and maintainability. Third, by connecting a switching module in series with the parallel resonant capacitor branch, the switching between the LCC-N type compensation circuit and the SN type compensation circuit is achieved. The LCC-N type compensation circuit has constant current output characteristics, while the SN type compensation circuit has constant voltage output characteristics. Only one switching module needs to be set on the primary side to achieve the switching between constant current charging and constant voltage charging. The number of switches required is small, the control process is simple, and the potential failure points of the charging equipment are reduced.

[0033] Example 2 If the secondary inductor and the primary inductor are loosely coupled, the power transmission effect will not be optimal. In order to improve the power transmission effect, the wireless charging system of this application has better constant current output characteristics when switching to the LCC-N type compensation circuit and better constant voltage output characteristics when switching to the SN type compensation circuit. The coupling coefficient between the primary inductor Lp and the secondary inductor Ls is greater than a preset value.

[0034] The coupling coefficient, usually denoted by k, measures how much magnetic field is "interlocked" between the transmitting and receiving coils. When the transmitting coil is energized, it generates a magnetic field, and the receiving coil must intercept these magnetic field lines to induce a voltage. The coupling coefficient describes this interception capability, with values ​​between 0 and 1: k=0 indicates no coupling at all, and k=1 indicates ideal full coupling. The formula for calculating the coupling coefficient is: , where M is the mutual inductance between the secondary coil and the primary coil.

[0035] If there is an air gap between the primary and secondary coils, the coupling between the coils is relatively loose, resulting in a low coupling coefficient. This means most of the magnetic field will "leak" through the air gap, leading to poor power transmission. Since the coupling coefficient is a purely geometric quantity and extremely sensitive to position, the position and distance of the coils largely determine the value of k. Slightly increasing the distance will cause k to decrease drastically (approximately cubic decay). As the value of k decreases, the transmission efficiency decreases quadratically. Therefore, the wireless charging system in this application requires that the primary and secondary coils be vertically aligned and spaced close together, ensuring that the coupling coefficient between the primary inductor Lp and the secondary inductor Ls is greater than a preset value, such as k ≥ 0.8. This achieves better constant current and constant voltage output characteristics and improves power transmission efficiency.

[0036] Since the current is alternating current after inversion by the primary-side inverter circuit, and the direction will change periodically, if the switching module is a unidirectional switch, the current can only flow in one direction, which is not compatible with alternating current. In order to solve the above problems, this embodiment provides a switching module.

[0037] refer to Figure 2 , Figure 2 This document shows a structural diagram of a switch module provided in an embodiment of this application, as follows: Figure 2 As shown, the switch module S5 provided in this embodiment includes: First switching transistor S 51 Its source is connected between the first inductor Lpr and the first capacitor Cp, and its drain is connected to the second switch S. 52 The drain of the first switching transistor S; 51 The anode of the internal parasitic diode is connected between the first inductor Lpr and the first capacitor Cp, and the cathode is connected to the second switching transistor S. 52 The drain electrode.

[0038] Second switching transistor S 52 Its source is connected to the first terminal of the second capacitor Cpr, and the second switch S 52 The anode of the internal parasitic diode is connected to the first terminal of the second capacitor Cpr, and the cathode is connected to the first switching transistor S. 51 The drain electrode.

[0039] The switching module in this embodiment conducts bidirectional current through a bidirectional switch with back-to-back series-connected MOSFETs, making it compatible with AC power.

[0040] As described above, the primary-side compensation circuit includes a series resonant inductor Lpr, a parallel resonant capacitor Cpr, a series resonant capacitor Cp, and a switching module S5 connected in series with the parallel resonant capacitor Cpr. Lpr, Cpr, and Cp together form a reconfigurable resonant network. When the switching module S5 is closed, Cpr is connected in parallel to the circuit, forming an LCC-N type compensation circuit topology with the primary-side series capacitor Cp and the self-inductance Lp of the transmitting coil. In this case, the wireless charging system exhibits constant current output characteristics. When the switching module S5 is open, Cpr is disconnected from the circuit, leaving only the series resonant inductor Lpr and the series resonant capacitor Cp on the primary side. Together with the transmitting coil Lp and the secondary-side reflective impedance, they form an equivalent SN type compensation circuit topology. In this case, the wireless charging system exhibits constant voltage output characteristics. Therefore, by controlling the on / off state of the switch module S5, the switching between constant current charging and constant voltage charging can be controlled. Specifically, when the switch module S5 is on, the wireless charging system performs constant current charging; when the switch module S5 is off, the wireless charging system performs constant voltage charging, thereby achieving the switching between constant current charging and constant voltage charging through only one switch module S5.

[0041] In order to simultaneously meet the requirements of constant current output characteristics and constant voltage output characteristics, it is necessary to design the series resonant inductor Lpr, parallel resonant capacitor Cpr, and series resonant capacitor Cp. The design takes the coupling mechanism parameters Lp, Ls, M, coupling coefficient k, and operating frequency f as known input conditions, and takes the transmission power level as the target, and gradually determines the values ​​of each compensation element.

[0042] Step 1: Based on the tight coupling condition (usually the coupling coefficient k ≥ 0.8) and the design power P, initially select the series resonant inductor Lpr. The selection of Lpr is related to the input voltage U. DC It is related to the desired output power and can generally be determined through simulation optimization or empirical formulas. Its value determines the system impedance level and current stress.

[0043] Step 2: In the SN-type compensation (leakage inductance compensation) circuit with constant voltage output characteristics, the coupling mechanism is designed to be symmetrical according to the constant voltage condition, and the compensation capacitor C... p' It needs to resonate with the equivalent leakage inductance Lr, that is: (a) Because the coupling mechanism is designed symmetrically, therefore: (b) Where n is the ratio of the number of turns on the primary side to the number of turns on the secondary side, it can be further deduced that: (c) The leakage sensation that compensates for it is satisfied: (d) Since Cp' is derived from the series LC equivalent, the parameter design of Lpr and Cp satisfies: (e) From equations (c), (d), and (e), we get: (f) Thirdly, in the LCC-N type compensation circuit with constant current characteristics, the parallel resonant capacitor Cpr is equivalent to the first part of the capacitor C. C1 With the second part of the capacitor C C2 The sum must satisfy: (g); Among them, X C The impedance of the equivalent capacitance C is obtained by rearranging equation (g): ; Among them, L pr As the first inductor, L p For the primary inductance, C p Let C be the first capacitor, k be the coupling coefficient of the wireless charging system, and C be the capacitance.pr ω is the second capacitor, and ω is the operating angular frequency of the wireless charging system.

[0044] Once Lpr is determined, Cpr and Cp can also be uniquely determined, and the system parameter design is complete. In the completed wireless charging system, when switch module S5 is closed, the parallel resonant capacitor Cpr is connected to the compensation circuit. The primary-side compensation circuit is an LCC-N type compensation circuit, operating in constant current charging mode. When switch module S5 is open, the parallel resonant capacitor Cpr is disconnected from the compensation circuit, and the primary-side compensation circuit switches to an SN type compensation circuit, switching to constant voltage charging mode. Both modes can meet the resonance and output characteristic requirements.

[0045] The above describes the entire process of parameter design. When the series inductance Lpr is determined, Cpr and Cp can be uniquely determined. The selection of Lpr is related to the system's transmission power, and Lpr is determined by the transmission power. This embodiment provides a complete design flow from the coupling mechanism parameters to the values ​​of all compensation elements. Since only the primary side has compensation elements and the secondary side does not, there are fewer design variables, making it easier to implement and promote in engineering.

[0046] Example 3 Existing wireless charging systems with constant current and constant voltage charging modes can experience significant impacts when switching between modes if the charging power difference between the two modes is large. To address this issue, this embodiment provides a charging control method.

[0047] refer to Figure 3 , Figure 3 A flowchart illustrating the charging control method provided in an embodiment of this application is shown, such as... Figure 3 As shown, the control method includes: After charging begins, the S301 controls the wireless charging system to perform constant current charging.

[0048] refer to Figure 4 , Figure 4 The diagram shows a circuit structure for constant current charging according to an embodiment of this application. When constant current charging is required, a parallel resonant capacitor Cpr is connected in parallel to the circuit. Together with the primary-side series capacitor Cp and the self-inductance Lp of the transmitting coil, they form an LCC-N type compensation circuit topology. At this time, the wireless charging system exhibits constant current output characteristics.

[0049] S302 determines whether the constant voltage charging condition is met based on the charging power of the wireless charging system.

[0050] To avoid excessive power changes before and after switching to constant voltage charging, which could significantly impact the wireless charging system, it is necessary to determine whether the constant voltage charging conditions are met based on the charging power of the wireless charging system. If it is predicted that the power change will be within a relatively small range after switching to constant voltage charging, then constant voltage charging can be switched to.

[0051] S303 controls the wireless charging system to switch to constant voltage charging when the constant voltage charging conditions are met.

[0052] refer to Figure 5 , Figure 5 The diagram shows a circuit structure for constant voltage charging according to an embodiment of this application. When constant voltage charging is required, the parallel resonant capacitor Cpr is cut out from the circuit, leaving only the series resonant inductor Lpr and the series resonant capacitor Cp on the primary side. Together with the transmitting coil Lp and the secondary side reflection impedance, they form an equivalent SN-type compensation circuit topology. At this time, the system exhibits constant voltage output characteristics.

[0053] The charging control method provided in this embodiment controls the wireless charging system to perform constant current charging after charging starts. Then, it determines whether the constant voltage charging condition is met based on the charging power of the wireless charging system. If it is predicted that the change in charging power will be within a small range after switching to constant voltage charging, then it switches to constant voltage charging. This ensures that the change in charging power is as small as possible after switching to constant voltage charging, thereby reducing the impact on the wireless charging system.

[0054] Example 4 To achieve constant current output characteristics by connecting the parallel resonant capacitor Cpr in parallel to the circuit during constant current charging and to disconnect Cpr from the circuit during constant voltage charging, the wireless charging system is controlled to perform constant current charging by: controlling the switching module to be turned on; and controlling the wireless charging system to switch to constant voltage charging by: controlling the switching module to be turned off.

[0055] Idp is the DC output current of the primary side, Ids is the DC output current of the secondary side, Ip is the AC output current of the primary side inverter circuit, and Is is the input current of the secondary side rectifier circuit. Lp This represents the current in the primary-side transmitting coil.

[0056] The load resistance is R L The effective value Up of the AC voltage output by the primary-side inverter circuit and the equivalent output resistance R o It can be obtained by the following formula (1).

[0057] (1); The KVL equation derived from Kirchhoff's voltage law is as follows: (2); Among them, X Lp X is the impedance of the primary inductor Lp. Cp X is the impedance of the series resonant capacitor Cp. Cpr X is the impedance of the parallel resonant capacitor Cpr. Lpr X is the impedance of the series resonant inductor Lpr. Ls X is the impedance of the secondary inductor Ls. M Let M be the impedance of the mutual inductance between the primary inductance Lp and the secondary inductance Ls, then we have: (3); Where j is the imaginary unit, and ω is the operating angular frequency of the wireless charging system.

[0058] By solving the system of equations (2), we can obtain I p , I Lp , I s The expression is as follows: (4); For simplification, the symbols A and B introduced in equation (4) are respectively: (5); Define the transconductance gain G as the input current of the secondary rectifier circuit. I s The ratio of the effective value Up of the AC voltage output from the primary side: (6); To achieve the constant current output characteristic of the system, the equivalent output resistance must be satisfied. R o The change does not affect the input current of the secondary rectifier circuit. I s The magnitude of and the magnitude of the transconductance gain G can be obtained from formula (6). Let B A constant current charging condition is achieved when the current equals zero. Therefore, the conditional equation for constant current charging can be expressed as: (7); According to equations (4) and (7), the input impedance Z of the system is... IN It can be represented as: (8); To achieve zero-phase angle (ZPA) operation and constant-current charging mode, the input impedance should be... Z INTreating it as a pure resistor, the condition for the system to operate at zero phase angle can then be given as: (9); Based on equations (8) and (9), the final ZPA operating condition equation system is as follows: (10); Combining equations (4), (7), and (9), the input and output currents can be further simplified to: (11); According to equation (11), the gain G can be rewritten as: (12); As can be seen from equation (12), the transconductance gain G is not affected by the equivalent output resistance. R o The effect of this indicates that the system can achieve constant current output regardless of the load.

[0059] As mentioned above Figure 5 As shown, when the switching module S5 is disconnected, the parallel resonant capacitor... C pr Cut out the primary-side compensation circuit, and retain only the series resonant inductor in the primary-side compensation circuit. L pr With series resonant capacitor C p Define a series resonant inductor L pr With series resonant capacitor C p If it is equivalent to a compensation capacitor C, then the impedance X of the compensation capacitor C is... C Represented as: (13); For the secondary rectifier circuit, the load voltage U L The relationship between the output voltage of the SN-type compensation circuit (i.e., the effective value Us of the AC voltage input to the secondary rectifier circuit) and the output voltage is as follows: (14); If only the influence of the fundamental component is considered, then the peak value U of the input AC voltage of the SN compensation circuit is... PP With effective value U P They are represented as follows: (15); Combining equations (14) and (15), we get: (16); Equivalent load R at the secondary bridge port E : (17); Since the leakage inductance equivalent model is similar to the transformer model, the leakage inductance compensation system of the SN type compensation circuit has constant voltage output characteristics when tightly coupled.

[0060] refer to Figure 6 , Figure 6 This diagram shows an equivalent model of the leakage inductance of an SN-type compensation circuit according to an embodiment of this application. In the diagram, L... r L m , and n are the equivalent leakage inductance, equivalent magnetizing inductance, and equivalent primary-to-secondary turns ratio of the equivalent model of the L-type leakage inductance, respectively. The specific equivalent relationship is as follows: (18); Among them, the compensation capacitors C and L r To achieve resonance in a full-bridge inverter circuit, the following equation must be satisfied: (19); According to equations (18) and (19), the value of the compensation capacitor C is: (20); Based on the relationship between the transformer's input and output voltages and the turns ratio, we can obtain approximate expressions for the input and output voltages and output power of the SN-type compensation circuit as shown in equation (21): (twenty one); P out It is the output power of the SN compensation topology.

[0061] From equation (21), it can be concluded that the voltage gain of the primary and secondary sides depends only on the mutual inductance M and the self-inductance L of the secondary side. S It is related to the load and therefore has a constant voltage output characteristic.

[0062] The component parameters of a wireless charging system according to one embodiment of this application are shown in Table 1: Table 1 Component Parameters of Wireless Charging System

[0063] refer to Figure 7 , Figure 7 The simulated output voltage and simulated output current curves of the LCC-N type compensation circuit of the wireless charging system provided in this application embodiment are shown, as follows: Figure 7 As shown, the LCC-N type compensation circuit has a constant current characteristic that is independent of the load under resonant conditions. The system startup time is 0~0.01s. After startup, the system load increases from 5Ω to 50Ω, a tenfold change. After the output current reaches the stable operating point, the rate of change is only about 19%.

[0064] refer to Figure 8 , Figure 8 The simulated output voltage and simulated output current curves of the SN-type compensation circuit of the wireless charging system provided in this application embodiment are shown, as follows: Figure 8 As shown, the SN-type compensation circuit has a constant voltage characteristic independent of load under resonance conditions. The system startup time is 0~0.01s. The system load starts at 0.01s and increases from 5Ω to 50Ω, a tenfold change in load. After the output voltage reaches the stable operating point, the rate of change is only about 8%.

[0065] Therefore, it can be seen that the wireless charging system and its charging control method of this application have excellent constant current and constant voltage output characteristics.

[0066] Through the above theoretical analysis and simulation verification, the LCC-N type compensation circuit has load-independent constant current characteristics over a wide load range, with output current fluctuation of less than 20%; the SN type compensation circuit has load-independent constant voltage characteristics under tight coupling conditions, with output voltage fluctuation of less than 10%, which fully meets the charging requirements of lithium batteries.

[0067] As mentioned above, when the change in charging power is within a small range, switching to constant voltage charging can minimize the change in charging power after switching to constant voltage charging, thereby reducing the impact on the wireless charging system. However, to completely avoid the impact on the wireless charging system, the charging power must remain constant when switching from constant current charging to constant voltage charging.

[0068] Therefore, determining whether the constant voltage charging condition is met based on the charging power of the wireless charging system includes: determining whether the charging power reaches a preset power value; wherein, the preset power value is the power value corresponding to the constant current charging power and constant voltage charging power of the wireless charging system being equal; if yes, it is determined that the constant voltage charging condition is met; if no, it is determined that the constant voltage charging condition is not met.

[0069] The above control scheme ensures that the power remains constant when the wireless charging system switches from constant current charging to constant voltage charging, thereby minimizing the impact.

[0070] refer to Figure 9 , Figure 9 This application provides an embodiment of the charging power variation curves over time during constant current charging and constant voltage charging. Figure 9 As can be seen from the data, the power is the same at around 0.019s. At this time, switching to constant voltage mode will have the least impact on the system.

[0071] refer to Figure 10 , Figure 10 This application provides an embodiment of the charging application that shows the charging voltage variation over time during constant current charging and constant voltage charging. Figure 10As can be seen, at 0.019s, the charging voltage of constant current charging is approximately 429V.

[0072] refer to Figure 11 , Figure 11 This application provides an embodiment of the charging current curves over time during constant current charging and constant voltage charging. Figure 11 As can be seen, at 0.019s, the charging current of constant current charging is approximately 44A.

[0073] Combination Figure 10 and Figure 11 It can be seen that the optimal switching point is when the load resistance is 9.75 ohms. Furthermore, at this point, the output current and output voltage are close, resulting in a smaller current surge during switching. Combined with... Figure 10 and Figure 11 It can also be seen that during the charging process, the resistance of the load increases from 5Ω to 35Ω.

[0074] Switching the switching module at a high voltage can damage the switching devices and circuits. To avoid this problem, when the constant voltage charging condition is met, the wireless charging system is switched to constant voltage charging. This includes: controlling the phase shift angle between the first and second inverter bridges of the primary inverter circuit to gradually decrease from 180° to 0°; controlling the wireless charging system to switch from constant current charging to constant voltage charging; and controlling the phase shift angle between the first and second inverter bridges of the primary inverter circuit to gradually increase from 0° to 180°.

[0075] When the wireless charging system is initially working, the switch module S5 is in the closed state, the parallel resonant capacitor Cpr is connected to the compensation circuit, the compensation circuit is an LCC-N type compensation circuit, in constant current charging mode, the drive signal of the primary inverter circuit is a square wave, the phase shift angle βc between the first inverter bridge and the second inverter bridge is 180°, that is, the first inverter bridge and the second inverter bridge drive complement each other, and the maximum output voltage is achieved.

[0076] The soft switching process using phase-shift control is divided into two parts. The first part is the phase-shift angle control in constant current mode, where the phase-shift angle between the inverter bridge containing switches S1 and S2 and the inverter bridge containing switches S3 and S4 is defined as β. c The phase shift angle βc is reduced from 180° to 0°, so that the drive signals of switches S1, S3 and switches S2, S4 are the same. In constant current mode, the effective value Up of the AC voltage output by the primary inverter circuit gradually decreases to zero.

[0077] The second part is that when βc decreases to 0°, the switch module S5 is turned off, causing the parallel resonant capacitor Cpr to be cut out of the primary side compensation circuit. The compensation circuit is switched to an SN type compensation circuit and switched to constant voltage charging mode. Then, the phase shift angle βc is increased from 0° to 180°, so that the effective value Up of the AC voltage output by the primary side inverter circuit in constant voltage mode gradually increases from zero to the maximum.

[0078] Similarly, the process of switching from constant voltage mode to constant current mode is as follows: first, the effective value Up of the AC voltage output by the primary inverter circuit in constant voltage mode is gradually reduced to zero through phase shift control. When the phase shift angle βc becomes 0°, the switching module S5 is turned on, so that the parallel resonant capacitor is connected to the primary compensation circuit. Then, the phase shift angle βc is gradually increased to 180°, so that the effective value Up of the AC voltage output by the primary inverter circuit in constant current mode gradually increases from zero to the maximum.

[0079] refer to Figure 12 , Figure 12 The following is a timing diagram of the control signals for the phase angle reduction process switches S1~S5 provided in an embodiment of this application, as shown in the figure. Figure 12 As shown, after the switching begins, the phase shift angle between the first and second inverter bridges of the primary-side inverter circuit in constant current mode is gradually reduced by the digital controller (i.e., the effective duty cycle is reduced), causing the effective value Up of the AC voltage output by the primary-side inverter circuit to gradually decrease from its maximum value to zero. During this process, the wireless charging system maintains the LCC-N type compensation circuit topology, and the output current gradually decreases to zero, while the load power gradually decreases to zero.

[0080] When the output voltage Up of the primary-side inverter circuit drops to zero, the output power of the primary-side inverter circuit is zero. At this time, the switch module S5 is turned off, causing the parallel capacitor Cpr to be removed from the circuit. The topology of the compensation circuit changes from an LCC-N type compensation circuit to an SN type compensation circuit. Since the output voltage of the primary side is zero at this time, the current flowing through the switch module S5 at the moment of turn-off is zero, achieving zero-current turn-off and minimizing the impact on the wireless charging system.

[0081] refer to Figure 13 , Figure 13 The following is a timing diagram of the control signals for the phase-shift angle increasing process switches S1~S5 provided in an embodiment of this application, as shown in the figure. Figure 13 As shown, after the switching module S5 is turned off, the control of the primary inverter circuit is switched to the phase shift control corresponding to the constant voltage mode. Based on the resonant parameters of the SN type compensation circuit topology, the phase shift angle between the first inverter bridge and the second inverter bridge of the primary inverter circuit is gradually increased from 0° to 180° (or the target phase shift angle), so that the effective value of the output voltage of the primary inverter circuit gradually recovers from zero to the maximum value or the target value, and the system smoothly enters the constant voltage charging mode.

[0082] In the switching process of the switching module in this embodiment, a soft switching strategy of "first phase shifting to reduce voltage, then switching, and finally phase shifting to increase voltage" is adopted, which can minimize the impact on the wireless charging system and achieve a smooth and low-impact switching process.

[0083] refer to Figure 14 , Figure 14 A flowchart illustrating the turn-off process of the switching module provided in this application embodiment is shown, such as... Figure 14 As shown, the turn-off process of the switch module includes: S141, control the phase shift angle βc to decrease by 1°.

[0084] S142, determine whether the phase shift angle βc has reached 0°; if yes, proceed to step S143; if no, return to step S141.

[0085] S143, turn off the drive signal of switch module S5, thereby controlling switch module S5 to turn off.

[0086] S144, control the phase shift angle βc to increase by 1°.

[0087] S145, determine whether the phase shift angle βc has reached 180°; if yes, proceed to step S146; if no, return to step S144.

[0088] S146, end phase shift angle change control.

[0089] According to equations (4) and (7) mentioned above, the system's input impedance Z IN It can be represented as: (8); To achieve zero-phase angle (ZPA) operation and constant-current charging mode, the input impedance should be... Z IN Consider it as a pure resistor. Then, the condition for the system to operate at zero phase angle can be given as: (9); Based on equations (8) and (9), the final ZPA operating condition equations are: (10).

[0090] Example 5 Existing wireless charging systems with constant current and constant voltage charging modes have a large difference in charging power between the two charging modes when switching between them. This switching can cause a significant impact on the wireless charging system. To solve the above problem, this embodiment provides a charging control device.

[0091] See Figure 15 , Figure 15 This diagram illustrates the structure of a charging control device provided in an embodiment of this application. The charging control device includes: The first control module 10 is used to control the wireless charging system to perform constant current charging after charging begins.

[0092] Referring to the above Figure 4 When constant current charging is required, the parallel resonant capacitor Cpr is connected in parallel to the circuit, forming an LCC-N type compensation circuit topology with the primary-side series capacitor Cp and the self-inductance Lp of the transmitting coil. At this time, the wireless charging system exhibits constant current output characteristics.

[0093] The judgment module 20 is used to determine whether the constant voltage charging condition is met based on the charging power of the wireless charging system.

[0094] To avoid excessive power changes before and after switching to constant voltage charging, it is necessary to determine whether the constant voltage charging conditions are met based on the charging power of the wireless charging system. If it is predicted that the power change will be within a small range after switching to constant voltage charging, then switch to constant voltage charging.

[0095] The second control module 30 is used to control the wireless charging system to switch to constant voltage charging when the constant voltage charging conditions are met.

[0096] Referring to the above Figure 5 When constant voltage charging is required, the parallel resonant capacitor Cpr is cut out from the circuit, leaving only the series resonant inductor Lpr and the series resonant capacitor Cp on the primary side. Together with the transmitting coil Lp and the secondary side reflection impedance, they form an equivalent SN-type compensation circuit topology, at which point the system exhibits constant voltage output characteristics.

[0097] In order to achieve constant current output characteristics by connecting the parallel resonant capacitor Cpr in parallel to the circuit during constant current charging, the first control module 10 controls the wireless charging system to perform constant current charging by specifically performing the following operations: controlling the switch module S5 to turn on.

[0098] During constant voltage charging, Cpr is switched off from the circuit to achieve constant voltage output characteristics. When the second control module 30 controls the wireless charging system to switch to constant voltage charging, it is specifically used to control the switch module S5 to turn off.

[0099] To achieve the constant current output characteristic of the system, the equivalent output resistance must be satisfied. R o The change does not affect the input current of the secondary rectifier circuit. I s Therefore, when the first control module 10 controls the wireless charging system to perform constant current charging, the following conditions must be met: ; Among them, XLp X is the impedance of the primary inductor. Cp X is the impedance of the first capacitor. Cpr X is the impedance of the second capacitor. Lpr The impedance of the first inductor is given.

[0100] When the change in charging power is within a small range, constant voltage charging can be switched to minimize the change in charging power after switching to constant voltage charging, thus reducing the impact on the wireless charging system. However, to completely avoid the impact on the wireless charging system, the charging power must remain constant when switching from constant current charging to constant voltage charging. Therefore, when determining whether the constant voltage charging condition is met based on the charging power of the wireless charging system, the judgment module 20 is specifically used to: determine whether the charging power has reached a preset power value; wherein, the preset power value is the power value corresponding to the constant current charging power and constant voltage charging power of the wireless charging system being equal; if so, it is determined that the constant voltage charging condition is met.

[0101] By performing the above operations, the power remains unchanged when the wireless charging system switches from constant current charging to constant voltage charging, thereby minimizing the impact.

[0102] Referring to the above Figure 9 It can be seen that the power is the same at around 0.019s. At this time, switching to constant voltage mode will have the least impact on the system.

[0103] Referring to the above Figure 10 As can be seen, at 0.019s, the charging voltage of constant current charging is approximately 429V.

[0104] Referring to the above Figure 11 As can be seen, at 0.019s, the charging current of constant current charging is approximately 44A.

[0105] Combination Figure 10 and Figure 11 It can be seen that the optimal switching point is when the load resistance is 9.75 ohms. Furthermore, at this point, the output current and output voltage are close, resulting in a smaller current surge during switching.

[0106] Combination Figure 10 and Figure 11 It can also be seen that during the charging process, the resistance of the load increases from 5Ω to 35Ω.

[0107] Switching the switching module at a high voltage can damage the switching devices and circuits. To avoid this problem, the second control module 30, when controlling the wireless charging system to switch to constant voltage charging, specifically controls the phase shift angle between the first and second inverter bridges of the primary-side inverter circuit to gradually decrease from 180° to 0°; controls the wireless charging system to switch from constant current charging to constant voltage charging; and controls the phase shift angle between the first and second inverter bridges to gradually increase from 0° to 180°.

[0108] Input impedance Z IN If we consider them as purely resistive, then when the phase shift angle between the first inverter bridge and the second inverter bridge is 0°, the output voltage on the primary side is 0, which satisfies the following condition: ; Among them, X Lp X is the impedance of the primary inductor. Cp X is the impedance of the first capacitor, XCpr is the impedance of the second capacitor, and X... Lpr The impedance of the first inductor, X Ls The impedance is the secondary inductor.

[0109] Example 6 This embodiment provides a charging device, including: a primary-side inverter circuit, the input side of which is connected to a DC power supply, and the output voltage of the DC power supply is U. DC The primary-side inverter circuit includes two inverter bridges. The first inverter bridge includes two MOSFET switches, one above the other. The effective value of the output AC voltage of the primary-side inverter circuit is Up.

[0110] The primary-side compensation circuit includes a first inductor Lpr, a first capacitor Cp, and a primary-side inductor Lp connected in series. The first inductor Lpr is connected to the first terminal of the output side of the primary-side inverter circuit, and the primary-side inductor Lp is connected to the second terminal of the output side of the primary-side inverter circuit. The primary-side compensation circuit also includes a switching module S5 and a second capacitor Cpr. The first terminal of the second capacitor Cpr is connected between the first inductor Lpr and the first capacitor Cp through the switching module, and the second terminal of the second capacitor Cpr is connected between the primary inductor Lp and the second terminal of the output side of the primary-side inverter circuit. The switching module is used to control the wireless charging system to perform constant current charging or constant voltage charging. The first inductor Lpr is a series resonant inductor, the first capacitor Cp is a series resonant capacitor, and the second capacitor Cpr is a parallel resonant capacitor.

[0111] Since the current becomes alternating current after inversion by the primary-side inverter circuit, the direction will switch. If the switching module is a unidirectional switch, the current can only flow in one direction, which is not compatible with alternating current. In order to solve the above problem, this embodiment provides a switching module.

[0112] The switching module provided in this embodiment includes: The source of the first switching transistor is connected between the first inductor Lpr and the first capacitor Cp, and its drain is connected to the drain of the second switching transistor; the anode of the parasitic diode inside the first switching transistor is connected between the first inductor Lpr and the first capacitor Cp, and the cathode is connected to the drain of the second switching transistor.

[0113] The source of the second switching transistor is connected to the first terminal of the second capacitor Cpr. The anode of the parasitic diode inside the second switching transistor is connected to the first terminal of the second capacitor Cpr, and the cathode is connected to the drain of the first switching transistor.

[0114] The switching module in this embodiment conducts bidirectional current through a bidirectional switch with back-to-back series-connected MOSFETs, making it compatible with AC power.

[0115] As described above, the primary-side compensation circuit includes a series resonant inductor Lpr, a parallel resonant capacitor Cpr, a series resonant capacitor Cp, and a switching module S5 connected in series with the parallel resonant capacitor Cpr. Lpr, Cpr, and Cp together form a reconfigurable resonant network. When the switching module S5 is closed, Cpr is connected in parallel to the circuit, forming an LCC-N type compensation circuit topology with the primary-side series capacitor Cp and the self-inductance Lp of the transmitting coil. At this time, the system exhibits constant current output characteristics. When the switching module S5 is open, Cpr is disconnected from the circuit, leaving only the series resonant inductor Lpr and the series resonant capacitor Cp on the primary side. Together with the transmitting coil Lp and the secondary-side reflective impedance, they form an equivalent SN type compensation circuit topology. At this time, the system exhibits constant voltage output characteristics. Therefore, by controlling the on / off state of the switch module S5, the switching between constant current charging and constant voltage charging can be controlled. That is, when the switch module is on, the wireless charging system performs constant current charging; when the switch module is off, the wireless charging system performs constant voltage charging, thereby realizing the switching between constant current charging and constant voltage charging through only one switch module.

[0116] In order to meet the design requirements of both constant current mode and constant voltage mode, the series resonant inductor Lpr, parallel resonant capacitor Cpr, and series resonant capacitor Cp need to be designed. The design takes the coupling mechanism parameters Lp, Ls, M, coupling coefficient k, and operating frequency f as known input conditions, and takes the transmission power level as the target, and gradually determines the values ​​of each compensation element.

[0117] Step 1: Based on the tight coupling condition (usually the coupling coefficient k ≥ 0.8) and the design power P, initially select the series resonant inductor Lpr. The selection of Lpr is related to the input voltage UDC and the desired output power, and can generally be determined through simulation optimization or empirical formulas. Its value determines the system impedance level and current stress.

[0118] Step 2: In SN-type compensation (leakage inductance compensation) mode, based on the constant voltage condition, the coupling mechanism is designed to be symmetrical, and the compensation capacitor C... p' It needs to resonate with the equivalent leakage inductance Lr, that is: (a) Because the coupling mechanism is designed symmetrically, therefore: (b) Where n is the ratio of the number of turns on the primary side to the number of turns on the secondary side, it can be further deduced that: (c) The leakage sensation that compensates for it is satisfied: (d) Since Cp' is derived from the series LC equivalent, the parameter design of Lpr and Cp satisfies: (e) From equations (c), (d), and (e), we get: (f) Thirdly, in the LCC-N type compensation circuit with constant current characteristics, the parallel resonant capacitor Cpr is equivalent to the first part of the capacitor C. C1 With the second part of the capacitor C C2 The sum must satisfy: (g); Among them, X C The impedance of the equivalent capacitance C is obtained by rearranging equation (g): ; Among them, L pr As the first inductor, L p For the primary inductance, C p Let C be the first capacitor, k be the coupling coefficient of the wireless charging system, and C be the capacitance. pr ω is the second capacitor, and ω is the operating angular frequency of the wireless charging system.

[0119] Once Lpr is determined, Cpr and Cp can also be uniquely determined, and the parameter design of the wireless charging system is complete. In the completed wireless charging system, when switch module S5 is closed, the parallel resonant capacitor Cpr is connected to the primary-side compensation circuit. The primary-side compensation circuit is an LCC-N type compensation circuit, operating in constant current charging mode. When switch module S5 is open, the parallel resonant capacitor Cpr is disconnected from the primary-side compensation circuit, which switches to an SN type compensation circuit, operating in constant voltage charging mode. Both modes can meet the resonance and output characteristic requirements.

[0120] The above describes the entire parameter design process. When the series inductor Lpr is determined, Cpr and Cp can be uniquely determined. The selection of Lpr is related to the transmission power of the charging device, and Lpr is determined by the transmission power. This embodiment provides a complete design flow from the coupling mechanism parameters to the values ​​of all compensation components, with fewer design variables, facilitating engineering implementation and promotion.

[0121] If there is an air gap between the primary and secondary coils, the coupling between the coils is relatively loose, resulting in a low coupling coefficient. This means most of the magnetic field will "leak" through the air gap. The coupling coefficient is a purely geometric quantity, extremely sensitive to position. Once the coil placement and distance are determined, k is essentially fixed. Slightly increasing the distance will cause k to decrease drastically (approximately cubic attenuation). When k decreases, the transmission efficiency decreases quadratically. Therefore, in the wireless charging system of this application, the positions of the primary and secondary coils must be perpendicularly aligned and the distance between them small, ensuring that the coupling coefficient between the primary and secondary inductors is greater than a preset value, such as k ≥ 0.8. To ensure a small distance between the primary and secondary coils, the charging device can be installed on the ground of the parking space.

[0122] Example 7 This embodiment provides a vehicle including a secondary inductor Ls. The first end of the secondary inductor Ls is connected to the first terminal of the input side of the secondary rectifier circuit, and the second end of the secondary inductor Ls is connected to the second terminal of the input side of the secondary rectifier circuit. When the vehicle is used in conjunction with the charging device of the above embodiment, the secondary inductor Ls and the primary inductor Lp in the charging device form a mutual inductance, thereby forming a high-frequency alternating magnetic field to realize contactless transmission of electrical energy.

[0123] The secondary inductor and secondary rectifier circuit can be set in the vehicle chassis, which makes it easy to align with the charging equipment on the ground of the parking space and keep the distance small. This increases the coupling coefficient between the secondary inductor in the vehicle and the primary inductor in the charging equipment, thereby optimizing the constant current output characteristics and constant voltage output characteristics.

[0124] Example 8 This embodiment provides an electronic device, including a processor and a memory. The processor is used to execute a charging control program stored in the memory to implement the charging control method provided in the above embodiment. The electronic device can be installed in a charging device or in a vehicle.

[0125] refer to Figure 16 , Figure 16This diagram illustrates the structure of an electronic device according to an embodiment of this application. The electronic device 1600 in this embodiment may include at least one processor 1601, a memory 1602, at least one network interface 1604, and other user interfaces 1603. The various components in the electronic device 1600 are coupled together via a bus system 1605. It is understood that the bus system 1605 is used to implement communication between these components. In addition to a data bus, the bus system 1605 also includes a power bus, a control bus, and a status signal bus. However, for clarity, all buses are referred to as bus system 1605.

[0126] The user interface 1603 may include a display, keyboard, or clicking device (e.g., mouse, trackball, touchpad, or touchscreen).

[0127] It is understood that the memory 1602 in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), and Direct Rambus RAM (DRRAM). The memory 1602 described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0128] In some implementations, memory 1602 stores elements, executable units or data structures, or subsets thereof, or extended sets thereof: operating system 16021 and application programs 16022.

[0129] The operating system 16021 includes various system programs, such as the framework layer, core library layer, and driver layer, used to implement various basic business functions and handle hardware-based tasks. The application program 16022 includes various applications, such as a media player and a browser, used to implement various application functions. The program implementing the method of the embodiments of this application can be included in the application program 16022.

[0130] In this embodiment of the application, the processor 1601 executes the methods provided in each method embodiment by calling the program or instructions stored in the memory 1602, specifically the program or instructions stored in the application program 16022.

[0131] The methods disclosed in the embodiments of this application can be applied to or implemented by processor 1601. Processor 1601 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the integrated logic circuit of the hardware or by instructions in the form of software in processor 1601. The processor 1601 may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or can be executed by a combination of hardware and software units in the decoding processor. The software units may be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory 1602. Processor 1601 reads the information in memory 1602 and completes the above method in conjunction with its hardware.

[0132] It is understood that the embodiments described herein can be implemented in hardware, software, firmware, middleware, microcode, or a combination thereof. For hardware implementation, the processing unit can be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers, microprocessors, other electronic units for performing the functions described herein, or combinations thereof.

[0133] For software implementation, the techniques described herein can be implemented by units that perform the functions described herein. The software code can be stored in memory and executed by a processor. The memory can be implemented in the processor or external to the processor.

[0134] Example 9 This application also provides a storage medium (computer-readable storage medium). This storage medium stores one or more programs. The storage medium may include volatile memory, such as random access memory; it may also include non-volatile memory, such as read-only memory, flash memory, hard disk, or solid-state drive; and it may also include combinations of the above types of memory.

[0135] When one or more programs in the storage medium can be executed by one or more processors to implement the above-described charging control method.

[0136] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0137] It should be noted that the terms "one implementation," "embodiment," "exemplary embodiment," and "some embodiments" used in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0138] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, or article that comprises a list of elements, or not only those elements, but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0139] The above embodiments are merely preferred embodiments provided to fully illustrate this application, and the scope of protection of this application is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on this application are all within the scope of protection of this application.

Claims

1. A wireless charging system, characterized in that, include: The primary-side inverter circuit has its input side connected to a DC power supply. The primary-side compensation circuit includes a first inductor and a first capacitor connected in series. The first inductor is connected to a first terminal on the output side of the primary-side inverter circuit, and the first capacitor is connected to the primary inductor. The primary inductor is connected to a second terminal on the output side of the primary-side inverter circuit. The primary-side compensation circuit also includes a switching module and a second capacitor. The first terminal of the second capacitor is connected between the first inductor and the first capacitor through the switching module, and the second terminal of the second capacitor is connected between the primary inductor and the second terminal on the output side of the primary-side inverter circuit. The switching module is used to control the wireless charging system to perform constant current charging or constant voltage charging. The secondary inductor has its first end connected to the first terminal of the input side of the secondary rectifier circuit, and its second end connected to the second terminal of the input side of the secondary rectifier circuit. The secondary inductor and the primary inductor form a mutual inductance.

2. The wireless charging system according to claim 1, characterized in that, The coupling coefficient between the primary inductor and the secondary inductor is greater than a preset value.

3. The wireless charging system according to claim 1, characterized in that, When the switch module is turned on, the wireless charging system performs constant current charging; When the switch module is turned off, the wireless charging system performs constant voltage charging.

4. The wireless charging system according to claim 1, characterized in that, The switching module includes: The first switching transistor has its source connected between the first inductor and the first capacitor, and its drain connected to the drain of the second switching transistor. The source of the second switching transistor is connected to the first terminal of the second capacitor.

5. The wireless charging system according to claim 1, characterized in that, The first inductor, the first capacitor, the primary inductor, and the second capacitor satisfy the following condition: ； ； Among them, L pr L is the first inductor. p For the primary-side inductance, C p Let C be the first capacitor, k be the coupling coefficient of the wireless charging system, and C be the first capacitor. pr ω is the second capacitor, and ω is the operating angular frequency of the wireless charging system.

6. A charging control method, applied to the wireless charging system according to any one of claims 1 to 5, characterized in that, The charging control method includes: After charging begins, the wireless charging system is controlled to perform constant current charging; Determine whether the constant voltage charging condition is met based on the charging power of the wireless charging system. When the constant voltage charging condition is met, the wireless charging system is controlled to switch to constant voltage charging.

7. The charging control method according to claim 6, characterized in that, Controlling the wireless charging system to perform constant current charging includes: controlling the switch module to turn on; Controlling the wireless charging system to switch to constant voltage charging includes: controlling the switch module to turn off.

8. The charging control method according to claim 6, characterized in that, When the wireless charging system performs constant current charging, it meets the following conditions: ； Among them, X Lp X is the impedance of the primary inductor. Cp X is the impedance of the first capacitor. Cpr X is the impedance of the second capacitor. Lpr Let be the impedance of the first inductor.

9. The charging control method according to claim 6, characterized in that, Determining whether the constant voltage charging condition is met based on the charging power of the wireless charging system includes: Determine whether the charging power has reached a preset power value; wherein, the preset power value is the power value corresponding to the constant current charging power and constant voltage charging power of the wireless charging system being equal; If so, the constant voltage charging condition is met.

10. The charging control method according to claim 6, characterized in that, The primary-side inverter circuit includes a first inverter bridge and a second inverter bridge. When the constant voltage charging condition is met, the wireless charging system is controlled to switch to constant voltage charging, including: The phase shift angle between the first inverter bridge and the second inverter bridge is gradually reduced from 180° to 0°. Control the wireless charging system to switch from constant current charging to constant voltage charging; The phase shift angle between the first inverter bridge and the second inverter bridge is controlled to gradually increase from 0° to 180°.

11. The charging control method according to claim 10, characterized in that, When the phase shift angle between the first inverter bridge and the second inverter bridge is 0°, the following condition is satisfied: ； Among them, X Lp X is the impedance of the primary inductor. Cp X is the impedance of the first capacitor. Cpr X is the impedance of the second capacitor. Lpr X is the impedance of the first inductor. Ls The impedance of the secondary inductor is given.

12. A charging control device for implementing the method according to any one of claims 6 to 11, characterized in that, include: The first control module is used to control the wireless charging system to perform constant current charging after charging begins. The judgment module is used to determine whether the constant voltage charging condition is met based on the charging power of the wireless charging system. The second control module is used to control the wireless charging system to switch to constant voltage charging when the constant voltage charging condition is met.

13. A charging device, characterized in that, include: The primary-side inverter circuit has its input side connected to a DC power supply. The primary-side compensation circuit includes a first inductor and a first capacitor connected in series. The first inductor is connected to a first terminal on the output side of the primary-side inverter circuit, and the first capacitor is connected to the primary-side inductor. The primary-side inductor is connected to a second terminal on the output side of the primary-side inverter circuit. The primary-side compensation circuit also includes a switching module and a second capacitor. The first terminal of the second capacitor is connected between the first inductor and the first capacitor through the switching module, and the second terminal of the second capacitor is connected between the primary-side inductor and the second terminal on the output side of the primary-side inverter circuit. The switching module is used to control the wireless charging system to perform constant current charging or constant voltage charging.

14. A vehicle, characterized in that, include: The secondary inductor has a first end connected to the first terminal of the input side of the secondary rectifier circuit, and a second end connected to the second terminal of the input side of the secondary rectifier circuit. When the vehicle is used in conjunction with the charging equipment of claim 12, the secondary inductor and the primary inductor form a mutual inductance.

15. An electronic device, characterized in that, include: A processor and a memory, the processor being configured to execute a charging control program stored in the memory to implement the charging control method of any one of claims 6 to 11.

16. A storage medium, characterized in that, The storage medium stores one or more programs, which can be executed by one or more processors to implement the charging control method of any one of claims 6 to 11.

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