Three-dimensional coil and planar coil combined wireless charging system

Abstract

The utility model provides a three-dimensional coil and planar coil combined wireless charging system, which relates to the technical field of wireless charging and comprises a transmitting end and a receiving end. The transmitting end comprises a direct-current power supply, an inverter circuit, a transmitting end compensation circuit and a transmitting coil; the receiving end comprises a receiving coil, a receiving end compensation circuit and a rectification filter circuit. Wherein the transmitting coil comprises a manganese zinc ferrite magnetic core and a three-dimensional coil, and the three-dimensional coil is spirally and densely wound on the outer side of the manganese zinc ferrite magnetic core; the receiving coil comprises a planar coil and manganese zinc ferrite flat magnetic bars, the planar coil is wound into a circular ring shape, the manganese zinc ferrite flat magnetic bars are alternately arranged on the circular ring-shaped planar coil along the normal direction and the tangential direction, and the difference between two adjacent normal manganese zinc ferrite flat magnetic bars is 60 degrees; the difference between two adjacent tangential manganese zinc ferrite flat magnetic bars is 60 degrees, and the difference between the adjacent normal manganese zinc ferrite flat magnetic bar and tangential manganese zinc ferrite flat magnetic bar is 30 degrees.

Description

TECHNICAL FIELD

[0001] The utility model relates to wireless charging technical field especially relates to a kind of three-dimensional coil and the wireless charging system of plane coil combination. BACKGROUND

[0002] With the rapid development of unmanned aerial vehicle wireless charging technology, its charging performance demand is increasing, however, due to the difficulty of unmanned aerial vehicle to land accurately on the top of transmitting coil, transmitting coil and unmanned aerial vehicle receiving coil are difficult to ideal alignment, offset occurs, and then significantly reduces the coupling coefficient, greatly affects the charging power and efficiency of wireless charging system.

[0003] The existing unmanned aerial vehicle wireless charging system usually adopts the magnetic coupling mode of transmitting plane coil and receiving plane coil facing each other to realize wireless power transmission. For example, the Chinese utility model patent with publication number CN221509199U discloses a "wireless charging system and device", which realizes wireless power transmission by two coil groups in series and stacking. This method has defects, the multi-coil structure is complex, the volume and mass are large, and the installation on the unmanned aerial vehicle will greatly increase the additional burden; at the same time, under the condition of high power or long time continuous work, the heat dissipation is limited by the complex structure, the heat dissipation path is narrow and the heat dissipation efficiency is low, which affects the system performance and safety. UTILITY MODEL CONTENTS

[0004] In view of the deficiencies of the prior art, the utility model provides a wireless charging system of three-dimensional coil and plane coil combination. It overcomes the problems of poor anti-offset ability of magnetic coupling coil, low charging power, low transmission efficiency, complex structure, large volume and mass, poor heat dissipation performance and other problems of the prior art unmanned aerial vehicle wireless charging system, and realizes fast and efficient charging of unmanned aerial vehicle by the combination of three-dimensional coil and plane coil.

[0005] A wireless charging system of three-dimensional coil and plane coil combination includes a transmitting end and a receiving end.

[0006] The transmitting end includes a DC power supply, an inverter circuit, a transmitting end compensation circuit and a transmitting coil; the inverter circuit is connected with the DC power supply, the transmitting end compensation circuit is connected with the inverter circuit, and the transmitting coil is connected with the transmitting end compensation circuit.

[0007] The transmitting end compensation circuit includes a first transmitting end resonant inductor L f , a first transmitting end resonant capacitor C f , and a first transmitting end compensation capacitor C1; one end of the first transmitting end resonant inductor L f serves as the first access end of the transmitting end compensation circuit; the first transmitting end resonant inductor L fThe other end of the first transmitting end resonant capacitor C f The other end of the first transmitting end resonant capacitor C f The other end of the first transmitting end resonant capacitor C

[0008] The inverter circuit comprises a first MOSFET Q1, a second MOSFET Q2, a third MOSFET Q3 and a fourth MOSFET Q4, wherein the source of the first MOSFET Q1 is connected with the drain of the second MOSFET Q2 and the first access end of the transmitting end compensation circuit, the source of the third MOSFET Q3 is connected with the drain of the fourth MOSFET Q4 and the second access end of the transmitting end compensation circuit; the drain of the first MOSFET Q1 is connected with the drain of the third MOSFET Q3 and the positive pole of the direct current power supply, the source of the second MOSFET Q2 is connected with the source of the fourth MOSFET Q4 and the negative pole of the direct current power supply;

[0009] The first MOSFET Q1 and the second MOSFET Q2 are connected in series, the third MOSFET Q3 and the fourth MOSFET Q4 are connected in series, and the two MOSFET bridge arms are formed after being connected in series, and the two MOSFET bridge arms are connected in parallel to form the inverter circuit;

[0010] The inverter circuit further comprises an inverter control module, and the gates of the first MOSFET Q1, the second MOSFET Q2, the third MOSFET Q3 and the fourth MOSFET Q4 are connected with the inverter control module respectively;

[0011] The transmitting coil comprises a manganese-zinc ferrite magnetic core and a three-dimensional coil, and the three-dimensional coil is tightly wound outside the manganese-zinc ferrite magnetic core;

[0012] The first transmitting end resonant inductor L f The first transmitting end resonant capacitor C f The first transmitting end compensation capacitor C1 and the transmitting coil jointly form a transmitting end resonant network, wherein the first transmitting end resonant inductor L f and the first transmitting end resonant capacitor C f occur parallel resonance, and the transmitting coil and the first transmitting end compensation capacitor C1 are connected in series with the first transmitting end resonant capacitor C f in parallel resonance;

[0013] The receiving end comprises a receiving coil, a receiving end compensation circuit and a rectification filter circuit, the receiving coil induces a magnetic field generated by the transmitting coil, the receiving end compensation circuit is connected with the receiving coil, and the rectification filter circuit is connected with the receiving end compensation circuit;

[0014] The receiving coil comprises a planar coil and manganese-zinc ferrite flat magnetic rods, the planar coil is wound in a circular ring shape, and the manganese-zinc ferrite flat magnetic rods are arranged alternately along a normal direction and a tangential direction on the circular ring-shaped planar coil; two adjacent manganese-zinc ferrite flat magnetic rods along the normal direction are 60° apart, two adjacent manganese-zinc ferrite flat magnetic rods along the tangential direction are 60° apart, and adjacent manganese-zinc ferrite flat magnetic rods along the normal direction and the tangential direction are 30° apart;

[0015] The receiving end compensation circuit comprises a first receiving end compensation capacitor C2, a fifth MOSFET Q5, a second receiving end compensation capacitor C3 and a sixth MOSFET Q6, one end of the first receiving end compensation capacitor C2 is connected with one access end of the receiving coil, the other end of the first receiving end compensation capacitor C2 is connected with one end of the second receiving end compensation capacitor C3 and a first access end of the rectification filter circuit respectively, the fifth MOSFET Q5 is connected in parallel with the first receiving end compensation capacitor C2, the other end of the second receiving end compensation capacitor C3 is connected with the other access end of the receiving coil and a second access end of the rectification filter circuit respectively, and the sixth MOSFET Q6 is connected in parallel with the second receiving end compensation capacitor C3;

[0016] The receiving coil and the first receiving end compensation capacitor C2 jointly constitute a receiving end resonance network, and the receiving coil and the first receiving end compensation capacitor C2 are in series resonance, the receiving coil and the second receiving end compensation capacitor C3 jointly constitute a receiving end resonance network, and the receiving coil and the second receiving end compensation capacitor C3 are in parallel resonance;

[0017] The rectification filter circuit comprises a first diode D1, a second diode D2, a third diode D3, a fourth diode D4 and a filter capacitor C4, wherein the positive electrode of the first diode D1 is connected with the negative electrode of the second diode D2, as a first access end of the rectification filter circuit, the positive electrode of the third diode D3 is connected with the negative electrode of the fourth diode D4, as a second access end of the rectification filter circuit, the negative electrode of the first diode D1 is connected with the negative electrode of the third diode D3, and one end of the filter capacitor C4 is connected with the negative electrode of the first diode D1 and the negative electrode of the third diode D3, the positive electrode of the second diode D2 is connected with the positive electrode of the fourth diode D4, and the other end of the filter capacitor C4 is connected with the positive electrode of the second diode D2 and the positive electrode of the fourth diode D4;

[0018] The first diode D1 and the second diode D2 are in series connection, the third diode D3 and the fourth diode D4 are in series connection, two diode bridge arms are formed after the series connection, and the two diode bridge arms and the filter capacitor C4 are in parallel connection to constitute the rectification filter circuit.

[0019] The receiving end further comprises a charging control module, which comprises a current sampling module, a voltage sampling module, a battery, and a control module, the sampling ends of the current sampling module and the voltage sampling module are connected with the battery, the control module is connected with the current sampling module and the voltage sampling module, and the control module is further connected with the gate of the fifth MOSFET Q5 and the gate of the sixth MOSFET Q6.

[0020] The technical scheme has the beneficial effects that:

[0021] The utility model provides a kind of wireless charging system of three-dimensional coil and planar coil combination, in solving the problems such as poor anti-offset capability of magnetic coupling coil, low charging power and low transmission efficiency in prior art of unmanned aerial vehicle wireless charging system, while, it also has the advantages of simple structure, portable device, excellent heat dissipation and the like. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a wireless charging system provided by the utility model embodiment;

[0023] Figure 2 It is a structural schematic diagram of a transmitting coil and a receiving coil provided by the utility model embodiment;

[0024] In the figure, 1-transmitting coil, 2-receiving coil, 3-manganese zinc ferrite magnetic core, 4-manganese zinc ferrite flat magnetic rod;

[0025] Figure 3 It is a circuit schematic diagram of a wireless charging system provided by the utility model embodiment. DETAILED DESCRIPTION

[0026] The specific implementation of the utility model will be described in further detail below in combination with the drawings and embodiments. The following embodiments are used to illustrate the utility model, but not to limit the scope of the utility model.

[0027] A kind of wireless charging system of three-dimensional coil and planar coil combination, as shown in Figure 1 It includes transmitting end and receiving end;

[0028] The transmitting end includes direct current power supply, inverter circuit, transmitting end compensation circuit and transmitting coil;The direct current power supply provides stable direct current power for system;The inverter circuit is connected with the direct current power supply, and converts direct current into high-frequency alternating current;The transmitting end compensation circuit is connected with the inverter circuit, for adjusting the electrical characteristics of transmitting end, so that transmitting end is in resonance state;The transmitting coil is connected with the transmitting end compensation circuit, for converting high-frequency alternating current into alternating electromagnetic field.

[0029] The transmitting end compensation circuit comprises: a first transmitting end resonant inductor L f , a first transmitting end resonant capacitor C f , and a first transmitting end compensation capacitor C1; one end of the first transmitting end resonant inductor L f serves as a first access end of the transmitting end compensation circuit; the other end of the first transmitting end resonant inductor L f is connected to one end of the first transmitting end resonant capacitor C f and one end of the first transmitting end compensation capacitor C1 respectively; the other end of the first transmitting end resonant capacitor C f serves as a second access end of the transmitting end compensation circuit and is connected to one access end of the transmitting coil; the other end of the first transmitting end compensation capacitor C1 is connected to the other access end of the transmitting coil.

[0030] As shown in Figure 3 , the inverter circuit comprises: a first MOSFET Q1, a second MOSFET Q2, a third MOSFET Q3, and a fourth MOSFET Q4, wherein the source of the first MOSFET Q1 is connected to the drain of the second MOSFET Q2 and to the first access end of the transmitting end compensation circuit, the source of the third MOSFET Q3 is connected to the drain of the fourth MOSFET Q4 and to the second access end of the transmitting end compensation circuit; the drain of the first MOSFET Q1 is connected to the drain of the third MOSFET Q3 and to the positive pole of the direct current power supply, and the source of the second MOSFET Q2 is connected to the source of the fourth MOSFET Q4 and to the negative pole of the direct current power supply.

[0031] The first MOSFET Q1 and the second MOSFET Q2 are connected in series, and the third MOSFET Q3 and the fourth MOSFET Q4 are connected in series, forming two MOSFET bridge arms in series, and the two MOSFET bridge arms are connected in parallel to form the inverter circuit.

[0032] The inverter circuit further comprises an inverter control module, which can modulate PWM waves according to different charging requirements to control the frequency, size, waveform quality, and power factor of the output voltage of the inverter circuit; the gates of the first MOSFET Q1, the second MOSFET Q2, the third MOSFET Q3, and the fourth MOSFET Q4 are connected to the inverter control module respectively to receive control signals from the inverter control module to control the conduction or turn-off of the MOSFETs.

[0033] As shown in Figure 2As shown, the transmitting coil 1 includes a manganese-zinc ferrite core 3 and a three-dimensional coil which is tightly wound outside the manganese-zinc ferrite core; the transmitting coil is a solenoid coil, the magnetic field generated by the solenoid coil is relatively concentrated and has strong directivity, the magnetic flux density is large, the coupling efficiency with the receiving end coil is enhanced, the energy transmission efficiency of the wireless charging system is improved, and the solenoid coil structure is simple and easy to manufacture.

[0034] The first transmitting end resonant inductance L f The first transmitting end resonant capacitance C f The first transmitting end compensation capacitance C1 and the transmitting coil together constitute a transmitting end resonant network, wherein the first transmitting end resonant inductance L f The first transmitting end resonant capacitance C f occur in parallel resonance, and the transmitting coil and the first transmitting end compensation capacitance C1 are connected in series with the first transmitting end resonant capacitance C f occur in parallel resonance. When the operating frequency of the inverter circuit is the resonant frequency, magnetic coupling resonant wireless power transmission can be realized, greatly improving the transmission efficiency.

[0035] The receiving end includes a receiving coil, a receiving end compensation circuit and a rectification and filtering circuit, the receiving coil induces the magnetic field generated by the transmitting coil to generate an electromotive force, the receiving end compensation circuit is connected with the receiving coil and is used for adjusting the electrical characteristics of the receiving end to make the receiving end in a resonant state, and the rectification and filtering circuit is connected with the receiving end compensation circuit and is used for converting alternating current into direct current.

[0036] As shown in the figure, Figure 2 The receiving coil 2 includes a planar coil and a manganese-zinc ferrite flat magnetic rod 4, the planar coil is wound in a circular ring shape, and the manganese-zinc ferrite flat magnetic rods are arranged alternately along the normal direction and the tangential direction on the circular ring-shaped planar coil; two adjacent normal manganese-zinc ferrite flat magnetic rods are 60° apart, two adjacent tangential manganese-zinc ferrite flat magnetic rods are 60° apart, and adjacent normal manganese-zinc ferrite flat magnetic rods and tangential manganese-zinc ferrite flat magnetic rods are 30° apart.

[0037] In the case that the receiving coil is not ideally aligned with the transmitting coil, due to the manganese-zinc ferrite being placed alternately along the normal direction and the tangential direction, the magnetic field remains relatively uniform, greatly enhancing the anti-offset capability and improving the wireless charging power and efficiency. In addition, due to the addition of manganese-zinc ferrite, the manganese-zinc ferrite normal-tangential alternating enhanced circular ring coil can effectively reduce the size under the same power output compared with the traditional planar coil, thereby improving the power density of the system and making it more lightweight, suitable for dynamic wireless charging equipment such as unmanned aerial vehicles.

[0038] There is a certain gap between the receiving coil and the transmitting coil, which can effectively dissipate heat and reduce the negative impact of heat on system performance.

[0039] The receiving end compensation circuit comprises a receiving end first compensation capacitor C2, a fifth MOSFET Q5, a receiving end second compensation capacitor C3 and a sixth MOSFET Q6, one end of the receiving end first compensation capacitor C2 is connected with one access end of the receiving coil, the other end of the receiving end first compensation capacitor C2 is connected with one end of the receiving end second compensation capacitor C3 and a first access end of the rectification filter circuit respectively, the fifth MOSFET Q5 is connected in parallel with the receiving end first compensation capacitor C2, the other end of the receiving end second compensation capacitor C3 is connected with the other access end of the receiving coil and a second access end of the rectification filter circuit respectively, and the sixth MOSFET Q6 is connected in parallel with the receiving end second compensation capacitor C3.

[0040] The receiving coil and the receiving end first compensation capacitor C2 jointly constitute a receiving end resonance network, and the two are in series resonance, the receiving coil and the receiving end second compensation capacitor C3 jointly constitute a receiving end resonance network, and the two are in parallel resonance, when the working frequency is the resonance frequency, the magnetic coupling resonance type wireless power transmission can be realized, and the transmission efficiency is greatly improved.

[0041] The gates of the fifth MOSFET Q5 and the sixth MOSFET Q6 are respectively used for receiving on-off control signals to control the conduction or turn-off of the fifth MOSFET Q5 and the sixth MOSFET Q6, the receiving end first compensation capacitor C2 is short-circuited, the wireless charging system is an LCC-P type resonance compensation network, the system is constant current output, the battery is constant current charging, when the charging voltage approaches the set cutoff voltage, the constant current charging is ended, the fifth MOSFET Q5 is turned off, the sixth MOSFET Q6 is turned on, the receiving end second compensation capacitor C3 is short-circuited, the wireless charging system is an LCC-S type resonance compensation network, the system is constant voltage output, the battery is constant voltage charging, in the constant voltage charging mode, the battery end voltage gradually increases, and the current gradually decreases, when the charging current approaches the set minimum value, the constant voltage charging is ended, and the charging is terminated. In the above embodiment, the charging mode is switched according to the change of the battery SOC in the charging process, the battery life is maintained, and the power transmission efficiency is improved.

[0042] The rectification filter circuit comprises a first diode D1, a second diode D2, a third diode D3, a fourth diode D4 and a filter capacitor C4, wherein the positive electrode of the first diode D1 is connected with the negative electrode of the second diode D2 as a first access end of the rectification filter circuit, the positive electrode of the third diode D3 is connected with the negative electrode of the fourth diode D4 as a second access end of the rectification filter circuit; the negative electrode of the first diode D1 is connected with the negative electrode of the third diode D3 and one end of the filter capacitor C4, and the positive electrode of the second diode D2 is connected with the positive electrode of the fourth diode D4 and the other end of the filter capacitor C4;

[0043] The first diode D1 and the second diode D2 are connected in series, and the third diode D3 and the fourth diode D4 are connected in series to form two diode bridge arms, and the two diode bridge arms are connected in parallel with the filter capacitor C4 to form the rectification filter circuit.

[0044] The receiving end further comprises a charging control module, the charging control module comprises a current sampling module, a voltage sampling module, a battery, a control module, the sampling ends of the current sampling module and the voltage sampling module are connected with the battery to obtain a charging current and a charging voltage, the control module is connected with the current sampling module and the voltage sampling module to decide different charging modes of the system according to the obtained charging current and charging voltage, and the control module is further connected with the gate of the fifth MOSFET Q5 and the gate of the sixth MOSFET Q6 to control the conduction or turn-off of the fifth MOSFET Q5 and the sixth MOSFET Q6 and switch the charging mode.

[0045] When the battery SOC is lower than 10%, the inverter control module adjusts the output of the inverter circuit by modulating the duty cycle of the PWM wave to charge in a small current mode; when the battery SOC is 10% to 80%, the control module turns on the fifth MOSFET Q5 by sending a trigger pulse and turns off the sixth MOSFET Q6 to charge in a constant current mode; when the capacity of the battery exceeds 80%, the control module turns on the sixth MOSFET Q6 by sending a trigger pulse and turns off the fifth MOSFET Q5 to charge in a constant voltage mode.

[0046] The above description is only the preferred embodiment of the present disclosure and the explanation of the applied technical principles. It should be understood by those skilled in the art that the utility model range involved in the embodiments of the present disclosure is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or equivalent features without departing from the above utility model concept. For example, the above features are replaced with the technical features disclosed in the embodiments of the present disclosure (but not limited to) having similar functions to form a technical solution.

Claims

1. A wireless charging system of a combination of a three-dimensional coil and a planar coil, characterized by, The transmitter and the receiver are included; The transmitter includes a direct current power supply, an inverter circuit, a transmitter compensation circuit and a transmitter coil; the inverter circuit is connected with the direct current power supply, the transmitter compensation circuit is connected with the inverter circuit, and the transmitter coil is connected with the transmitter compensation circuit; The transmitting end compensation circuit comprises: a first transmitting end resonant inductor L f , a first transmitting end resonant capacitor C f , and a first transmitting end compensation capacitor C1; one end of the first transmitting end resonant inductor L f serves as a first access end of the transmitting end compensation circuit; the other end of the first transmitting end resonant inductor L f is connected to one end of the first transmitting end resonant capacitor C f and one end of the first transmitting end compensation capacitor C1 respectively; the other end of the first transmitting end resonant capacitor C f serves as a second access end of the transmitting end compensation circuit and is connected to one access end of the transmitting coil; the other end of the first transmitting end compensation capacitor C1 is connected to the other access end of the transmitting coil; The inverter circuit includes a first MOSFET Q1, a second MOSFET Q2, a third MOSFET Q3 and a fourth MOSFET Q4, wherein the source of the first MOSFET Q1 is connected with the drain of the second MOSFET Q2 and the first access end of the transmitter compensation circuit, the source of the third MOSFET Q3 is connected with the drain of the fourth MOSFET Q4 and the second access end of the transmitter compensation circuit; the drain of the first MOSFET Q1 is connected with the drain of the third MOSFET Q3 and the positive pole of the direct current power supply, and the source of the second MOSFET Q2 is connected with the source of the fourth MOSFET Q4 and the negative pole of the direct current power supply; The receiver includes a receiver coil, a receiver compensation circuit and a rectification filter circuit, the receiver coil is used to induce the magnetic field generated by the transmitter coil, the receiver compensation circuit is connected with the receiver coil, and the rectification filter circuit is connected with the receiver compensation circuit; The receiver compensation circuit includes a receiver first compensation capacitor C2, a fifth MOSFET Q5, a receiver second compensation capacitor C3 and a sixth MOSFET Q6, one end of the receiver first compensation capacitor C2 is connected with one access end of the receiver coil, the other end of the receiver first compensation capacitor C2 is connected with one end of the receiver second compensation capacitor C3 and the first access end of the rectification filter circuit respectively; the fifth MOSFET Q5 is connected in parallel with the receiver first compensation capacitor C2; the other end of the receiver second compensation capacitor C3 is connected with the other access end of the receiver coil and the second access end of the rectification filter circuit respectively; the sixth MOSFET Q6 is connected in parallel with the receiver second compensation capacitor C3; The receiver coil and the receiver first compensation capacitor C2 together constitute a receiver resonance network, and the two are in series resonance; the receiver coil and the receiver second compensation capacitor C3 together constitute a receiver resonance network, and the two are in parallel resonance. The rectification filter circuit comprises a first diode D1, a second diode D2, a third diode D3, a fourth diode D4 and a filter capacitor C4, wherein the positive electrode of the first diode D1 is connected with the negative electrode of the second diode D2 as a first access end of the rectification filter circuit, the positive electrode of the third diode D3 is connected with the negative electrode of the fourth diode D4 as a second access end of the rectification filter circuit; the negative electrode of the first diode D1 is connected with the negative electrode of the third diode D3 and connected with one end of the filter capacitor C4, and the positive electrode of the second diode D2 is connected with the positive electrode of the fourth diode D4 and connected with the other end of the filter capacitor C4.

2. The wireless charging system of claim 1, wherein, The first transmitting end resonant inductance L f The first transmitting end resonant capacitance C f The first transmitting end compensation capacitance C1 and the transmitting coil together constitute a transmitting end resonant network, wherein the first transmitting end resonant inductance L f is in parallel resonance with the first transmitting end resonant capacitance C f The transmitting coil and the first transmitting end compensation capacitance C1 are in series with the first transmitting end resonant capacitance C f in parallel resonance.

3. The wireless charging system of claim 1, wherein the three-dimensional coil is combined with a planar coil. The first MOSFET Q1 and the second MOSFET Q2 are connected in series, and the third MOSFET Q3 and the fourth MOSFET Q4 are connected in series to form two MOSFET bridge arms, and the two MOSFET bridge arms are connected in parallel to form an inverter circuit.

4. The wireless charging system of claim 1, wherein the three-dimensional coil is combined with a planar coil. The inverter circuit further comprises an inverter control module, and the gates of the first MOSFET Q1, the second MOSFET Q2, the third MOSFET Q3 and the fourth MOSFET Q4 are connected with the inverter control module.

5. The wireless charging system of claim 1, wherein, The first diode D1 and the second diode D2 are connected in series, and the third diode D3 and the fourth diode D4 are connected in series to form two diode bridge arms, and the two diode bridge arms are connected in parallel with the filter capacitor C4 to form a rectification filter circuit.

6. The wireless charging system of claim 1, wherein the three-dimensional coil is combined with a planar coil. The receiving end further comprises a charging control module, and the charging control module comprises a current sampling module, a voltage sampling module, a battery, a control module, the sampling ends of the current sampling module and the voltage sampling module are connected with the battery, the control module is connected with the current sampling module and the voltage sampling module respectively, and the control module is connected with the gates of the fifth MOSFET Q5 and the sixth MOSFET Q6.

7. The wireless charging system of claim 1, wherein the three-dimensional coil is combined with a planar coil. The transmitting coil comprises a manganese-zinc ferrite core and a three-dimensional coil, and the three-dimensional coil is tightly wound outside the manganese-zinc ferrite core.

8. The wireless charging system of claim 1, wherein, The receiving coil comprises a planar coil and a manganese-zinc ferrite flat magnetic rod, the planar coil is wound in a circular ring shape, and the manganese-zinc ferrite flat magnetic rods are alternately arranged on the circular ring-shaped planar coil along the normal direction and the tangential direction; two adjacent normal manganese-zinc ferrite flat magnetic rods are different by 60°, two adjacent tangential manganese-zinc ferrite flat magnetic rods are different by 60°, and adjacent normal manganese-zinc ferrite flat magnetic rods and tangential manganese-zinc ferrite flat magnetic rods are different by 30°.

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