A wireless charging system

Abstract

This utility model discloses a wireless charging system. The wireless charging system includes: a resonant module for receiving electrical signals, the resonant module comprising a resonant inductor and a resonant capacitor connected in series; and a frequency conversion module comprising a first switch and a capacitive component connected in series, the branch containing the first switch and the capacitive component being connected in parallel with the resonant capacitor; the first switch is configured to remain in a conducting state when detecting a metal object. In this embodiment, the first switch is turned on during metal object detection, thereby connecting the capacitive component in parallel with the resonant capacitor, and the first switch is turned off during wireless charging, thereby disconnecting the capacitive component from the resonant capacitor. This ensures that the frequency of the oscillation wave during metal object detection is different from the frequency of the oscillation wave during wireless charging, which helps avoid interference from nearby wireless charging systems during metal object detection and improves the accuracy of metal object detection.

Description

Technical Field

[0001] This utility model relates to the field of wireless charging technology, and in particular to a wireless charging system. Background Technology

[0002] With further technological advancements, wireless power transfer has emerged as an efficient and convenient mechanism for powering or charging battery-powered mobile devices such as mobile phones, tablet PCs, digital cameras, and MP3 players. Wireless power transfer systems typically consist of a primary-side transmitter and a secondary-side receiver. The primary-side transmitter is magnetically coupled to the secondary-side receiver.

[0003] Before wireless power transmission, the wireless power transmission system detects the quality factor (Q factor) of the primary coil. The quality factor is used to detect the presence of foreign objects (e.g., metallic objects) that may adversely affect power transmission within the power transmission range. When foreign objects are present, the quality factor will decrease and power loss will increase.

[0004] However, when two wireless chargers are close together, they interfere with each other, resulting in inaccurate quality factor measurements and poor accuracy in metal detection. Utility Model Content

[0005] This invention provides a wireless charging system to avoid interference from nearby wireless charging systems during metal object detection, thereby improving the accuracy of metal object detection.

[0006] This utility model provides a wireless charging system, which includes: a resonant module and a frequency conversion module;

[0007] The resonant module is used to receive electrical signals. The resonant module includes a resonant inductor and a resonant capacitor connected in series. The frequency conversion module includes a first switch and a capacitive component connected in series. The branch containing the first switch and the capacitive component is connected in parallel with the resonant capacitor.

[0008] The branch containing the resonant inductor and the resonant capacitor is configured to generate an oscillating wave in response to the electrical signal; the first switch is configured to remain on when a metal object is detected.

[0009] Optionally, the capacitive component includes: at least one frequency conversion capacitor;

[0010] The first terminal of each frequency conversion capacitor is connected to the first switch, and the second terminal of each frequency conversion capacitor is connected to the resonant capacitor.

[0011] Optionally, the wireless charging system further includes a filtering module, which includes a filtering capacitor, and the branch containing the resonant capacitor and the resonant inductor is connected in parallel with the filtering capacitor; the filtering module is configured to provide the electrical signal based on alternating current.

[0012] Optionally, the wireless charging system further includes: an inverter module for connecting to a DC power supply, and the inverter module is also connected to the filter module;

[0013] The inverter module is configured to provide the AC power based on the DC power supplied by the DC power source. The wireless charging system also includes a control module.

[0014] The branch containing the resonant capacitor and the resonant inductor is connected to the control module, and the control module is also connected to the first switch and the inverter module respectively;

[0015] The control module is configured to control the first switch to close when a metal object is detected.

[0016] Optionally, the control module includes: a processor and a step-down circuit;

[0017] The processor is connected to the inverter module and the frequency conversion module respectively. The input terminal of the buck circuit is connected to the branch containing the resonant capacitor and the resonant inductor. The output terminal of the buck circuit is connected to the processor.

[0018] The step-down circuit is configured to reduce the waveform voltage of the oscillation wave generated by the resonant module; the processor is configured to control the first switch to close when a metal object is detected.

[0019] Optionally, the filtering module further includes: a first filtering inductor and a second filtering inductor;

[0020] The first end of the first filter inductor and the first end of the second filter inductor are connected to the AC power. The second end of the first filter inductor is connected to the first end of the filter capacitor. The second end of the filter capacitor is connected to the second end of the second filter inductor. The filter capacitor is connected in parallel with the branch containing the resonant inductor and the resonant capacitor.

[0021] Optionally, the inverter module includes: a second switch, a third switch, a fourth switch, and a fifth switch;

[0022] The first terminal of the second switch is connected to the positive terminal of the DC power supply. The second terminal of the second switch is connected to the first terminal of the third switch. The second terminal of the third switch is connected to the negative terminal of the DC power supply. The first terminal of the third switch is also connected to the filter module. The first terminal of the fourth switch is connected to the positive terminal of the DC power supply. The second terminal of the fourth switch is connected to the first terminal of the fifth switch. The second terminal of the fifth switch is connected to the negative terminal of the DC power supply. The first terminal of the fifth switch is also connected to the filter module. The control terminals of the second, third, fourth, and fifth switches are all connected to the control module. The second terminals of the third and fifth switches are also grounded.

[0023] Optionally, it may also include: a switch module;

[0024] The switching module is connected in parallel with the branch containing the resonant inductor and the resonant capacitor, and the switching module is also connected to the control module;

[0025] The switch module is configured to remain on during metal detection.

[0026] Optionally, the switch module includes a sixth switch.

[0027] Optionally, the first switch is a transistor switch, a thyristor switch, a solid-state relay, or an integrated electronic switch.

[0028] In this embodiment of the invention, the first switch is turned on during metal detection, thereby connecting the capacitive component and the resonant capacitor in parallel. During wireless charging, the first switch is turned off, thereby disconnecting the capacitive component and the resonant capacitor. This ensures that the frequency of the oscillation wave during metal detection is different from the frequency of the oscillation wave during wireless charging, which helps to avoid interference from nearby wireless charging systems during metal detection and improves the accuracy of metal detection.

[0029] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a wireless charging system provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of another wireless charging system provided in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of another wireless charging system provided in this embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of another wireless charging system provided in this embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of another wireless charging system provided in this embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of another wireless charging system provided in this embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of another wireless charging system provided in this embodiment of the present invention;

[0038] Figure 8 This is a flowchart of a wireless charging method performed by the wireless charging system provided in this embodiment of the present invention;

[0039] Figure 9 This is a flowchart of another wireless charging method performed by the wireless charging system provided in this embodiment of the present invention. Detailed Implementation

[0040] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0041] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0042] This utility model provides a wireless charging system. This wireless charging system can be used for wireless charging of electronic devices. In this embodiment, the frequency conversion module is connected to the resonant module when the control module detects a metal object, thereby changing the frequency of the oscillation wave. This makes the frequency of the oscillation wave during metal object detection different from the frequency of the oscillation wave during wireless charging, which helps to avoid interference from nearby wireless charging systems during metal object detection and improves the accuracy of metal object detection. Figure 1 This is a schematic diagram of a wireless charging system provided in an embodiment of this utility model. (Refer to...) Figure 1 The wireless charging system includes a resonant module 130 and a frequency conversion module 140.

[0043] The resonant module 130 is used to receive the electrical signal V1. The resonant module 130 includes a resonant inductor L1 and a resonant capacitor C1 connected in series. The frequency conversion module includes a first switch S1 and a capacitive component X1 connected in series. The branch containing the first switch S1 and the capacitive component X1 is connected in parallel with the resonant capacitor C1. The branch containing the resonant inductor L1 and the resonant capacitor C1 is configured to generate an oscillating wave in response to the electrical signal V1. The first switch S1 is configured to remain in a conducting state when a metal object is detected. In this embodiment, the first switch S1 can be a transistor switch, a thyristor switch, a solid-state relay, or an integrated electronic switch, etc., and those skilled in the art can select and configure it according to design requirements and other factors.

[0044] Specifically, during metal detection, the first switch S1 in the frequency conversion module 140 is closed, and the capacitive component X1 is connected in parallel with the resonant capacitor C1 in the resonant module 130. Figure 2 This is a schematic diagram of another wireless charging system provided in an embodiment of this utility model. (Refer to...) Figure 2 The frequency conversion module 140 and the resonant module 130 together constitute the resonant cavity 200, and the electrical signal V1 oscillates within the resonant cavity, thereby generating an oscillation wave. For example, referring to... Figure 1 and Figure 2The capacitive component X1 consists of at least one frequency conversion capacitor C2. The first end of each frequency conversion capacitor C2 is connected to the first switch S1, and the second end of each frequency conversion capacitor C2 is connected to the resonant capacitor C1. That is, each frequency conversion capacitor C2 is connected in parallel and then connected in series with the first switch S1.

[0045] When a metal object enters the charging range of a wireless charging system, the resonant point generated by the resonant cavity 200 changes, and consequently, the frequency of the oscillation wave generated by the resonant cavity 200 also changes. Different resonant points result in different quality factors for the resonant cavity 200. Therefore, the presence of a metal object within the charging range of the wireless charging system can be determined based on the quality factor of the resonant cavity 200. The quality factor of the resonant cavity 200 can be calculated from the frequency of the oscillation wave generated by the resonant cavity 200.

[0046] The capacitive component X1 behaves like a capacitor. When the first switch S1 is closed, the capacitive component X1 is connected in parallel with the resonant capacitor C1 in the resonant module 130. At this time, the capacitive component X1 and the resonant capacitor C1 can be considered as a new capacitor. The capacitance of the equivalent new capacitor is the sum of the capacitance of the capacitive component X1 and the capacitance of the resonant capacitor C1. That is, the resonant cavity 200 can be considered as being composed of the resonant inductor L1 and the equivalent new capacitor. For example, the frequency of the oscillation wave generated by the resonant cavity 200 can be calculated by the following formula:

[0047]

[0048] Where f is the frequency of the oscillation wave; L is the inductance of the resonant cavity; and C is the capacitance of the resonant cavity.

[0049] As can be seen from the above formula, when the capacitance within the resonant cavity 200 increases, the frequency of the oscillation wave generated by the resonant cavity 200 decreases. Therefore, when the capacitive component X1 is connected in parallel with the resonant capacitor C1 in the resonant module 130, the frequency of the oscillation wave generated by the resonant cavity 200 decreases.

[0050] The quality factor of the resonant cavity 200 can be calculated using the following formula:

[0051]

[0052] Where Q is the quality factor of the resonant cavity; f is the frequency of the oscillation wave; L is the inductance of the resonant cavity; and R is the equivalent resistance of the devices in the resonant cavity.

[0053] As can be seen from the above formula, when the frequency of the oscillation wave generated by the resonant cavity 200 decreases, the quality factor of the resonant cavity 200 also decreases.

[0054] When a metal object enters the charging range of the wireless charging system, eddy currents are generated within the metal object. The magnetic field generated by the eddy currents will hinder the change of the original magnetic field, thereby changing the magnetic field distribution around the inductor in the resonant cavity 200, which in turn changes the self-inductance coefficient of the inductor, thus causing the inductance value of the inductor in the resonant cavity 200 to change.

[0055] As can be seen from the two formulas above, when the inductance value of the inductor inside the resonant cavity 200 changes, the frequency of the oscillation wave generated by the resonant cavity 200 changes, and the quality factor of the resonant cavity 200 also changes accordingly. Therefore, the presence of metal objects within the wireless charging system can be detected based on the quality factor of the resonant cavity 200.

[0056] When the quality factor of the resonant cavity 200 is outside the preset range, it indicates that there is a metal object within the charging range of the wireless charging system; when the quality factor of the resonant cavity 200 is within the preset range, it indicates that there is no metal object within the charging range of the wireless charging system. It should be noted that the preset range is a pre-set frequency range of the oscillation wave generated by the resonant cavity 200 when there is no metal object within the charging range of the wireless charging system. The preset range depends on the electrical characteristics of the resonant module 130 and the frequency conversion module 140, and can be set according to actual needs in practical applications. This embodiment does not impose any restrictions on this.

[0057] Figure 3 This is a schematic diagram of yet another wireless charging system provided in an embodiment of this utility model. (Refer to...) Figure 3 When there are no metal objects within the charging range of the wireless charging system, the first switch S1 is turned off, the capacitive component X1 is disconnected from the resonant capacitor C1, and the resonant cavity 200 consists only of the resonant inductor L1 and the resonant capacitor C1. At this time, the wireless charging system can charge the device.

[0058] In this embodiment of the invention, the first switch S1 is turned on during metal detection, thereby connecting the capacitive component X1 and the resonant capacitor C1 in parallel. During wireless charging, the first switch S1 is turned off, thereby disconnecting the connection between the capacitive component X1 and the resonant capacitor C1. This ensures that the frequency of the oscillation wave during metal detection is different from the frequency of the oscillation wave during wireless charging, which helps to avoid interference from nearby wireless charging systems during metal detection and improves the accuracy of metal detection.

[0059] The following describes the working process of the resonant cavity 200, taking the example that the resonant cavity 200 consists only of the resonant module 130.

[0060] After the resonant capacitor C1 completes its reverse charging, it will begin to discharge in reverse, repeating the above process. The electric field energy of the resonant capacitor C1 and the magnetic field energy of the resonant inductor L1 are constantly converted into each other, forming a periodic oscillating current, i.e., an oscillating wave.

[0061] Figure 4 This is a schematic diagram of another wireless charging system provided by an embodiment of the present utility model. Optionally, based on the above embodiments, refer to... Figure 4 The wireless charging system also includes a filter module 120.

[0062] The filtering module 120 includes a filtering capacitor C3, a resonant capacitor C1, and a branch containing a resonant inductor L1 connected in parallel with the filtering capacitor C3; the filtering module 120 is configured to provide an electrical signal V1 based on alternating current.

[0063] Optionally, continue to refer to Figure 4 In practical applications, the filter module 120 can also be equipped with a first filter inductor L2 and a second filter inductor L3.

[0064] In this circuit, the first terminal of the first filter inductor L2 and the first terminal of the second filter inductor L3 are connected to AC power. The second terminal of the first filter inductor L2 is connected to the first terminal of the filter capacitor C3. The second terminal of the filter capacitor C3 is connected to the second terminal of the second filter inductor L3. The filter capacitor C3 is connected in parallel with the branch containing the resonant inductor L1 and the resonant capacitor C1.

[0065] Based on the above embodiments, optionally, refer to... Figure 4 The wireless charging system also includes an inverter module 110.

[0066] Inverter module 110 is used to connect to DC power supply 10, and inverter module 110 is also connected to filter module 120. Inverter module 110 is configured to provide AC power based on DC power supplied by DC power supply 10.

[0067] Based on the above embodiments, optionally, refer to... Figure 4 The wireless charging system also includes a control module 150.

[0068] The branch containing the resonant capacitor C1 and the resonant inductor L1 is connected to the control module 150. The control module 150 is also connected to the control terminal of the first switch S1 and the control terminal of the inverter module 110. The control module 150 is configured to control the first switch S1 to close when a metal object is detected.

[0069] Specifically, when detecting whether there is a metal object within the charging range of the wireless charging system, the control module 150 drives the inverter module 110 to run for a preset time to convert the DC power output from the DC power supply 10 into AC power, thereby providing the required energy to the resonant module 130. It should be noted that the preset time is a pre-set running time of the inverter module 110 during the metal object detection process. In actual applications, it can be set according to actual needs; this embodiment does not impose any restrictions on this. The filter module 120 filters the AC power output from the inverter module 110 and outputs the filtered AC power to the resonant module 130, that is, outputs the electrical signal V1 to the resonant module 130. When the preset time is reached, the control module 150 stops driving the inverter module 110 and enables the frequency conversion module 140.

[0070] When metal object detection occurs, control module 150 stops driving inverter module 110, and inverter module 110 is completely turned off, effectively becoming an open circuit. Furthermore, control module 150 enables frequency conversion module 140, causing first switch S1 to close, thereby connecting capacitive component X1 in parallel with resonant capacitor C1 in resonant module 130. During metal object detection, control module 150 also detects the quality factor of the resonant cavity 200 formed by resonant module 130 and frequency conversion module 140.

[0071] If a metal object is present within the charging range of the wireless charging system, the control module 150 re-detects the quality factor of the resonant cavity 200 until no metal object is found within the charging range. Once no metal object is present within the charging range, the wireless charging system proceeds with normal wireless charging.

[0072] When the wireless charging system is wirelessly charging normally, the control module 150 controls the first switch S1 to turn off, and the capacitive component X1 is disconnected from the resonant capacitor C1.

[0073] When the wireless charging system charges the device, the frequency of the oscillation wave generated by the resonant cavity 200 is the frequency of the PWM signal output by the control module 150 to control the inverter module 110. At the start of charging, the resonant cavity 200 has an initial operating frequency. During the charging process, the frequency of the resonant cavity 200 may increase. Therefore, the frequency of the oscillation wave generated by the resonant cavity 200 during charging will not be lower than the initial operating frequency. In this embodiment, when detecting metal foreign objects, the inverter module 110 is disconnected, and the resonant cavity 200 oscillates freely. By incorporating the capacitive component X1, the frequency of the oscillation wave during metal detection is reduced, making the frequency of the oscillation wave during metal detection lower than the initial operating frequency at the start of wireless charging. This ensures that the frequency of the oscillation wave during metal detection is different from the frequency of the oscillation wave during wireless charging, avoiding mutual interference between adjacent wireless charging products and affecting the quality factor measurement.

[0074] In this embodiment, the inverter module 110, driven by the control module 150, converts the DC power output from the DC power supply 10 into AC power, and the filter module 120 filters the AC power output from the inverter module 110. When the wireless charging system detects a metal object, the control module 150 enables the frequency conversion module 140, connecting it to the resonant module 130, causing electromagnetic energy to oscillate in both the resonant module 130 and the frequency conversion module 140. When the wireless charging system performs wireless charging, the control module 150 stops enabling the frequency conversion module 140, disconnecting it from the resonant module 130, causing electromagnetic energy to oscillate in the resonant module 130, thus differentiating the frequency of the oscillation wave during metal detection from the frequency of the oscillation wave during wireless charging.

[0075] Figure 5 This is a schematic diagram of another wireless charging system provided by an embodiment of the present utility model. Optionally, based on the above embodiments, refer to... Figure 5 The control module 150 includes a processor 151 and a step-down circuit 152.

[0076] The processor 151 is connected to the inverter module 110 and the frequency conversion module 140 respectively. The input terminal of the buck circuit 152 is connected to the branch containing the resonant capacitor C1 and the resonant inductor L1, and the output terminal of the buck circuit 152 is connected to the processor 151. The buck circuit 152 is configured to reduce the waveform voltage of the oscillation wave generated by the resonant module. The processor 151 is configured to control the first switch S1 to close when a metal object is detected. In this embodiment, the input terminal of the buck circuit 152 can be connected to any position in the branch containing the resonant capacitor C1 and the resonant inductor L1.

[0077] In this embodiment, the step-down circuit 152 is used to reduce the waveform voltage of the oscillation wave so as to convert the oscillation wave into waveform data that can be acquired by the analog-to-digital converter in the processor 151.

[0078] Specifically, processor 151 drives inverter module 110 to run for a preset time to convert the DC power output from DC power supply 10 into AC power, thereby providing the required energy to resonant module 130. Filter module 120 filters the AC power output from inverter module 110 and outputs the filtered AC power to resonant module 130, providing electrical signal V1 to resonant module 130. When the preset time is reached, processor 151 stops driving inverter module 110 and enables frequency conversion module 140.

[0079] After the processor 151 enables the frequency conversion module 140, i.e., after the first switch S1 is closed, the buck circuit 152 acquires the oscillation wave generated by the resonant cavity 200 and generates waveform data based on the oscillation wave. For example, the buck circuit 152 adjusts the waveform of the oscillation wave generated by the resonant cavity 200 to generate waveform data. The adjustment of the oscillation wave by the buck circuit 152 can be an adjustment of the voltage of the oscillation wave. The processor 151 acquires the waveform data from the buck circuit 152 and calculates the quality factor of the resonant cavity 200 based on the waveform data. The processor 151 compares the calculated quality factor of the resonant cavity 200 with a preset range. When the quality factor of the resonant cavity 200 is outside the preset range, it is considered that there is a metal object within the charging range of the wireless charging system; when the quality factor of the resonant cavity 200 is within the preset range, it is considered that there is no metal object within the charging range of the wireless charging system.

[0080] For example, when processor 151 calculates the quality factor of resonant cavity 200 based on waveform data, processor 151 calculates the frequency of the oscillation wave from the waveform data. Based on the known frequency of the oscillation wave, processor 151 calculates the quality factor of the resonant cavity according to the following formula:

[0081]

[0082] Where Q is the quality factor of the resonant cavity; f is the frequency of the oscillation wave; L is the inductance of the resonant cavity; and R is the equivalent resistance of the devices in the resonant cavity.

[0083] Figure 6 This is a schematic diagram of another wireless charging system provided by an embodiment of the present utility model. Optionally, based on the above embodiments, refer to... Figure 6 The inverter module 110 includes: a second switch S2, a third switch S3, a fourth switch S4, and a fifth switch S5.

[0084] The first terminal of the second switch S2 is connected to the positive terminal of the DC power supply 10. The second terminal of the second switch S2 is connected to the first terminal of the third switch S3. The second terminal of the third switch S3 is connected to the negative terminal of the DC power supply 10. The first terminal of the third switch S3 is also connected to the first input terminal of the filter module 120. The first terminal of the fourth switch S4 is connected to the positive terminal of the DC power supply 10. The second terminal of the fourth switch S4 is connected to the first terminal of the fifth switch S5. The second terminal of the fifth switch S5 is connected to the negative terminal of the DC power supply 10. The first terminal of the fifth switch S5 is also connected to the second input terminal of the filter module 120. The control terminals of the second switch S2, the third switch S3, the fourth switch S4, and the fifth switch S5 are all connected to the control module 150. The second terminals of the third switch S3 and the fifth switch S5 are also grounded.

[0085] When the control module 150 stops driving the inverter module 110, the second switch S2, the third switch S3, the fourth switch S4, and the fifth switch S5 are all in the off state, and the inverter module 110 is open-circuited at this time. For example, the second switch S2, the third switch S3, the fourth switch S4, and the fifth switch S5 can all be switching transistors.

[0086] Figure 7 This is a schematic diagram of another wireless charging system provided by an embodiment of the present utility model. Optionally, based on the above embodiments, refer to... Figure 7 The wireless charging system also includes a switch module 160.

[0087] The switch module 160 is connected in parallel with the branch containing the resonant inductor L1 and the resonant capacitor C1. The switch module 160 is also connected to the control module 150. The switch module 160 is configured to maintain a conducting state when a metal object is detected. The control module 150 is configured to control the switch module to conduct when a metal object is detected.

[0088] Specifically, while enabling the frequency conversion module 140, the control module 150 also enables the switching module 160. At this time, the switching module 160 closes, short-circuiting the resonant module 130. (Continuing to refer to...) Figure 8 At this time, the resonant cavity 200 is composed of a resonant module 130, a frequency conversion module 140, and a switching module 160. When the switching module 160 is closed, the inverter module 110 and the filter module 120 in the wireless charging system are shielded, which helps to avoid interference from irrelevant devices during metal detection and stabilize the waveform of the oscillation wave. For example, the switching module 160 can be a sixth switch S6. The first end of the sixth switch S6 is connected to the first end of the resonant module 130, the second end of the sixth switch S6 is connected to the second end of the resonant module 130, and the control end of the sixth switch S6 is connected to the control module 150. Optionally, the sixth switch S6 can be a transistor switch, a thyristor switch, a solid-state relay, or an integrated electronic switch, etc. Those skilled in the art can reasonably configure the first end, second end, and control end of the sixth switch S6 to correspond to the ports of the selected type of switch according to the type of the sixth switch S6.

[0089] This utility model embodiment also provides a wireless charging method. Figure 8 This is a flowchart illustrating a wireless charging method performed by the wireless charging system provided in this embodiment of the present invention. This wireless charging method is performed by the wireless charging system provided in any of the above embodiments. The wireless charging system includes a frequency conversion module, wherein the frequency conversion module is equipped with a first switch. (Refer to...) Figure 8 The wireless charging method includes:

[0090] S110 provides electrical signals.

[0091] For example, combined Figure 7 The control module drives the inverter module to run for a preset time. During operation, the inverter module converts the DC power supplied by the DC power source into AC power. The filter module filters the AC power supplied by the inverter module to provide an electrical signal for the resonant module.

[0092] It should be noted that when the preset time is reached, the control module stops driving the inverter module, and the inverter module is completely shut down. At this time, the inverter module is equivalent to an open circuit.

[0093] S120, Keep the first switch on during metal detection.

[0094] Specifically, during metal detection, the first switch remains closed, so that during metal detection, the capacitive component is connected in parallel with the resonant capacitor in the resonant module, thereby changing the resonant point of the branch containing the resonant capacitor and resonant inductor during oscillation. It should be noted that during metal detection, the control module stops driving the inverter module, meaning the inverter module is effectively open-circuited.

[0095] The control module can detect the presence of metal objects by using the quality factor of the oscillation waves generated by the wireless charging system.

[0096] The frequency of the oscillating wave can be calculated using the following formula:

[0097]

[0098] Where f is the frequency of the oscillation wave; L is the inductance of the resonant cavity; and C is the capacitance of the resonant cavity.

[0099] Given the frequency of the oscillating wave, the quality factor of the resonant cavity can be calculated using the following formula:

[0100]

[0101] Where Q is the quality factor of the resonant cavity; f is the frequency of the oscillation wave; L is the inductance of the equivalent inductance in the resonant cavity; and R is the resistance of the equivalent resistance of the devices in the resonant cavity.

[0102] When the quality factor is outside the preset range, it is assumed that there is a metal object within the charging range of the wireless charging device; when the quality factor is within the preset range, it is assumed that there is no metal object within the charging range of the wireless charging device.

[0103] Figure 9 This is a flowchart illustrating another wireless charging method performed by the wireless charging system provided in this embodiment of the present invention. Optionally, based on the above embodiments, the wireless charging system further includes a switch module. (Refer to...) Figure 9After maintaining the first switch on during metal detection, the following steps are also included:

[0104] S130, Keep the switch module on during metal detection.

[0105] Specifically, when the switch module is closed, devices other than the resonant module and the frequency conversion module are shielded, which helps to avoid interference from irrelevant devices during the metal detection process and stabilize the waveform of the oscillation wave.

[0106] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.

[0107] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A wireless charging system, characterized by, include: Resonance module and frequency conversion module; The resonant module is used to receive electrical signals. The resonant module includes a resonant inductor and a resonant capacitor connected in series. The frequency conversion module includes a first switch and a capacitive component connected in series. The branch containing the first switch and the capacitive component is connected in parallel with the resonant capacitor. The first switch is configured to remain on when a metal object is detected.

2. The wireless charging system of claim 1, wherein, The capacitive component includes: at least one frequency conversion capacitor; The first terminal of each frequency conversion capacitor is connected to the first switch, and the second terminal of each frequency conversion capacitor is connected to the resonant capacitor.

3. The wireless charging system according to any one of claims 1-2, characterized in that, Also includes: A filtering module, comprising a filtering capacitor, wherein the branch containing the resonant capacitor and the resonant inductor is connected in parallel with the filtering capacitor; The filtering module is configured to provide the electrical signal based on alternating current.

4. The wireless charging system according to claim 3, characterized in that, Also includes: An inverter module is provided, which is used to connect to a DC power supply and is also connected to the filter module. The inverter module is configured to provide the AC power based on the DC power supplied by the DC power source.

5. The wireless charging system according to claim 4, characterized in that, Also includes: Control module; The branch containing the resonant capacitor and the resonant inductor is connected to the control module, and the control module is also connected to the first switch and the inverter module respectively; The control module is configured to control the first switch to close when a metal object is detected.

6. The wireless charging system according to claim 5, characterized in that, The control module includes: a processor and a step-down circuit; The processor is connected to the inverter module and the frequency conversion module respectively. The input terminal of the buck circuit is connected to the branch containing the resonant capacitor and the resonant inductor. The output terminal of the buck circuit is connected to the processor. The step-down circuit is configured to reduce the waveform voltage of the oscillation wave generated by the resonant module; the processor is configured to control the first switch to close when a metal object is detected.

7. The wireless charging system according to claim 5, characterized in that, The inverter module includes: a second switch, a third switch, a fourth switch, and a fifth switch; The first terminal of the second switch is connected to the positive terminal of the DC power supply. The second terminal of the second switch is connected to the first terminal of the third switch. The second terminal of the third switch is connected to the negative terminal of the DC power supply. The first terminal of the third switch is also connected to the filter module. The first terminal of the fourth switch is connected to the positive terminal of the DC power supply. The second terminal of the fourth switch is connected to the first terminal of the fifth switch. The second terminal of the fifth switch is connected to the negative terminal of the DC power supply. The first terminal of the fifth switch is also connected to the filter module. The control terminals of the second, third, fourth, and fifth switches are all connected to the control module. The second terminals of the third and fifth switches are also grounded.

8. The wireless charging system according to claim 3, characterized in that, The filtering module further includes a first filtering inductor and a second filtering inductor; The first end of the first filter inductor and the first end of the second filter inductor are connected to the AC power. The second end of the first filter inductor is connected to the first end of the filter capacitor. The second end of the filter capacitor is connected to the second end of the second filter inductor. The filter capacitor is connected in parallel with the branch containing the resonant inductor and the resonant capacitor.

9. The wireless charging system according to claim 3, characterized in that, Also includes: Switch module; The switching module is connected in parallel with the branch containing the resonant inductor and the resonant capacitor; The switch module is configured to remain on during metal detection.

10. The wireless charging system according to claim 9, characterized in that, The switch module includes: a sixth switch.

11. The wireless charging system according to claim 1, characterized in that, The first switch is a transistor switch, a thyristor switch, a solid-state relay, or an integrated electronic switch.

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