A near field communication method of a wireless charging system

Abstract

The application discloses a near field communication method of a wireless charging system, which comprises a transmitting end circuit and a receiving end circuit, the transmitting end circuit comprises a first resonant circuit and a third resonant circuit, the receiving end circuit comprises a second resonant circuit and a fourth resonant circuit, the transmitting end and the receiving end are both provided with a signal extraction circuit, the method comprises the following steps: transmitting high-power energy through the first resonant circuit and the second resonant circuit; realizing half-duplex communication and low-power energy transmission between the transmitting end and the receiving end by using the third resonant circuit and the fourth resonant circuit, the half-duplex communication is based on near field coupling, and a power signal is removed through the signal extraction circuit to obtain clean and effective communication signals; and the low-power energy transmission provides an auxiliary power supply for the receiving end or the transmitting end. The application can solve the problems of crowded frequency bands, signal interference and complex positioning, supports bidirectional auxiliary power supply transmission between the transmitting end and the receiving end, and realizes self-power supply or low-power consumption wake-up function.

Description

Technical Field

[0001] This invention relates to the field of wireless charging technology, and more specifically to a near-field communication method for a wireless charging system. Background Technology

[0002] In the field of wireless charging, with the development of technology, the requirements for charging efficiency and communication functions are becoming increasingly stringent. Traditional communication methods based on the 2.4GHz frequency band have many problems when applied to wireless charging systems, such as excessively long communication distances and limited frequency ranges. Simultaneous use by multiple devices can lead to frequency congestion and interference, making it difficult to achieve simultaneous operation of multiple wireless chargers within a short distance (within 20-100m). Furthermore, the transmitter and receiver need to confirm their positions after establishing communication, which complicates the communication process. In addition, existing wireless charging systems also have limitations in power supply methods, failing to flexibly provide auxiliary power between the transmitter and receiver, thus restricting the system's energy consumption and ease of use. Summary of the Invention

[0003] The purpose of this invention is to provide a near-field communication method for a wireless charging system. This invention can solve the problems of frequency congestion, signal interference, and complex positioning in traditional 2.4G frequency band communication. At the same time, this invention supports bidirectional auxiliary power transmission between the transmitter and receiver, realizing self-powered or low-power wake-up functions, significantly improving the stability and energy efficiency of multiple devices working together at close range.

[0004] The technical solution of the present invention is as follows: A near-field communication method for a wireless charging system, comprising a transmitting end circuit and a receiving end circuit, wherein the transmitting end circuit includes a first resonant circuit and a third resonant circuit, and the receiving end circuit includes a second resonant circuit and a fourth resonant circuit; both the transmitting end and the receiving end are provided with a signal extraction circuit; the method includes:

[0005] High-power energy is transmitted through the first resonant circuit and the second resonant circuit;

[0006] The third and fourth resonant circuits are used to realize half-duplex communication and low-power energy transmission between the transmitter and receiver. The half-duplex communication is based on near-field coupling, and the power signal is removed by the signal extraction circuit to obtain a clean and effective communication signal. The low-power energy transmission provides auxiliary power to the receiver or transmitter.

[0007] In the near-field communication method of the aforementioned wireless charging system, the third and fourth resonant circuits employ a series compensation or LCC compensation structure.

[0008] In the aforementioned near-field communication method of the wireless charging system, the coils of the first resonant circuit, the second resonant circuit, the third resonant circuit, and the fourth resonant circuit are orthogonally wound to eliminate or reduce mutual coupling and reduce the interference of power transmission on communication.

[0009] The aforementioned near-field communication method for a wireless charging system, wherein the signal extraction circuit performs signal extraction including:

[0010] The communication signal and the power signal are filtered by a filtering circuit to remove the power signal. The filtering circuit is one or a combination of a band-stop filter, a high-pass filter, or a band-pass filter. The center frequency of the band-stop filter is set to the power signal frequency, and the center frequency of the band-pass filter is set to the communication carrier frequency. The cutoff frequency of the high-pass filter is set between the power signal frequency and the communication signal frequency.

[0011] The filtered communication signal is converted into a binary sequence signal by a demodulation circuit.

[0012] In the aforementioned near-field communication method of the wireless charging system, the filter in the filtering circuit is a passive or active filter.

[0013] In the aforementioned near-field communication method of the wireless charging system, the communication signal transmission function is implemented by a processing module, a driving module, and a conversion circuit. The driving module is used to enhance the driving capability of the output signal of the processing module, enabling it to effectively drive the conversion circuit. The conversion circuit is responsible for modulating and amplifying the signal output by the driving module, converting it into a high-frequency AC signal suitable for transmission in a resonant circuit, thereby realizing the effective transmission of the communication signal.

[0014] In the aforementioned near-field communication method of the wireless charging system, when the receiver is not connected to a battery, the transmitter transmits low-power energy to the fourth resonant circuit through the third resonant circuit as an auxiliary power source for the receiver, thereby realizing the self-powering of the wireless charging system.

[0015] When the receiver is connected to a battery, it transmits a small amount of power to the transmitter through the fourth resonant circuit to provide auxiliary power, thereby waking up the transmitter and disconnecting it from the mains power input in the idle state.

[0016] The aforementioned near-field communication method for a wireless charging system includes a signal extraction circuit comprising a filtering circuit and a demodulation circuit; the filtering circuit is a combination of one or more of a band-stop filter, a high-pass filter, and a band-pass filter; the demodulation circuit includes a rectifier module, an amplifier module, and a comparator, used to convert the filtered communication signal into a binary sequence signal after rectification, amplification, and comparison.

[0017] In the aforementioned near-field communication method of the wireless charging system, the conversion circuit adopts a half-bridge or full-bridge inverter circuit to convert DC signals into high-frequency AC signals.

[0018] In the aforementioned near-field communication method of the wireless charging system, when the receiver of the wireless charging system is not connected to a battery, the transmitter of the wireless charging system transmits a small amount of energy to the fourth resonant circuit through the third resonant circuit as an auxiliary power source for the receiver, thereby realizing the self-powering of the wireless charging system; when the receiver of the wireless charging system is connected to a battery, the receiver transmits a small amount of energy to the third resonant circuit through the fourth resonant circuit to provide auxiliary power to the transmitter, so as to wake up the transmitter and disconnect it from the mains power input in the idle state.

[0019] Compared with existing technologies, this invention employs a near-field coupling communication method, avoiding interference issues associated with 2.4GHz band communication. It enables simultaneous operation of multiple wireless chargers within a short distance, simplifying the communication process and eliminating the need for location confirmation. The signal extraction circuit of this invention effectively eliminates power signals, ensuring the quality of the communication signal. Regarding power supply, this invention achieves flexible auxiliary power supply between the transmitter and receiver, enabling the wireless charging system to be self-powered and reducing transmitter power consumption during idle periods, thus improving the system's energy efficiency and ease of use. The rational design and layout of the components in this invention, along with the application of orthogonal winding, effectively reduces mutual interference, improving the performance and reliability of the entire wireless charging system. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the wireless charging system of the present invention;

[0021] Figure 2 This is a schematic diagram of different filtering methods in the signal extraction circuit;

[0022] Figure 3 This is an example diagram of a passive filter;

[0023] Figure 4 This is another example diagram of a passive filter;

[0024] Figure 5 This is a schematic diagram of the demodulation circuit;

[0025] Figure 6 This is a schematic diagram of communication signal transmission;

[0026] Figure 7 This is a schematic diagram illustrating a specific example of communication signal transmission;

[0027] Figure 8 This is a schematic diagram of LCC compensation for a resonant circuit;

[0028] Figure 9This is a schematic diagram of the resonant circuit coil winding;

[0029] Figure 10 This is an overall schematic diagram of the wireless charging system of the present invention. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention. The scope of protection of the present invention should include all the contents of the claims, and the following embodiments can enable those skilled in the art to have a more comprehensive understanding of the present invention.

[0031] Example 1: A near-field communication method for a wireless charging system, such as Figure 1 As shown, the system includes a transmitting circuit and a receiving circuit. The transmitting circuit includes a first resonant circuit and a third resonant circuit, and the receiving circuit includes a second resonant circuit and a fourth resonant circuit. Both the transmitting and receiving ends are equipped with signal extraction circuits (including a first signal extraction circuit and a second signal extraction circuit). The method includes:

[0032] High-power energy is transmitted through the first resonant circuit and the second resonant circuit;

[0033] The transmitter and receiver utilize a third and fourth resonant circuit to achieve half-duplex communication and low-power energy transfer. The half-duplex communication is based on near-field coupling, and a signal extraction circuit removes power signals to obtain a clean and effective communication signal. The low-power energy transfer provides auxiliary power to either the transmitter or receiver. When the receiver is not connected to a battery, the transmitter transfers low-power energy to the fourth resonant circuit through the third resonant circuit as auxiliary power to the receiver, enabling the wireless charging system to be self-powered. When the receiver is connected to a battery, the receiver transfers low-power energy to the third resonant circuit through the fourth resonant circuit to provide auxiliary power to the transmitter, thereby waking up the transmitter and disconnecting it from the mains (220V) input power in the idle state.

[0034] In this embodiment, the third resonant circuit and the fourth resonant circuit can be compensated by series (S) or LCC (inductor-capacitor-capacitor) compensation; the coil of the third resonant circuit and the coil of the first resonant circuit, as well as the coil of the fourth resonant circuit and the coil of the second resonant circuit, can be wound in an orthogonal manner to eliminate or reduce the coupling between them.

[0035] In this embodiment, the signal extraction circuit includes a filtering circuit and a demodulation circuit. Since the frequency of the transmitted power signal is lower than the frequency of the communication carrier signal, the filtering circuit can flexibly select band-stop, high-pass, and band-pass filters, as well as combinations thereof. Specifically, the center frequency of the band-stop filter should be set at the frequency of the power signal, the center frequency of the band-pass filter should be set at the frequency of the communication carrier signal, and the cutoff frequency of the high-pass filter should be set between the power signal frequency and the communication carrier signal frequency. For details, the signal extraction circuit can be found in [reference needed]. Figure 2 Examples of various filter combinations are shown. Figure 2 The resonant circuit in the image is either the third or fourth resonant circuit. The filter can be passive or active. See [example of passive filter] for details. Figure 3 and Figure 4 There are two methods. The demodulation circuit converts the signal after passing through the above filtering circuit into a binary sequence signal that the processing module can recognize.

[0036] In this embodiment, the communication signal transmission function is implemented by a processing module, a driving module, and a conversion circuit, and the signal transmission and reception share a common set of resonant circuits; such as Figure 6 and Figure 7 As shown, the driving module (also called the driving circuit) enhances the driving capability of the output signal of the processing module, enabling it to effectively drive the conversion circuit. The conversion circuit is responsible for modulating and amplifying the signal output by the driving module, converting it into a high-frequency AC signal suitable for transmission in the resonant circuit, thus achieving effective transmission of the communication signal. The resonant circuit can be as described above. Figure 7 Series compensation can be used, or other compensation methods can be employed, such as the following... Figure 8 LCC (inductor-capacitor-capacitor) compensation is provided. Communication signals can be provided by the processing module or by an oscillation generation circuit (such as a 555 timer). The conversion circuit can employ a half-bridge or full-bridge inverter topology. Furthermore, the coils of the first, second, third, and fourth resonant circuits are orthogonally wound to eliminate or reduce mutual coupling and mitigate power transmission interference with communication. Figure 9 As shown.

[0037] Example 2: This example provides a wireless charging system that implements the near-field communication method in Example 1, such as... Figure 1As shown, the system includes a transmitter circuit and a receiver circuit. The transmitter circuit includes a first resonant circuit, a third resonant circuit, a first signal extraction circuit, a first processing module, a first driving module, a first conversion circuit, a second driving module, and a third conversion circuit. The receiver circuit includes a second resonant circuit, a fourth resonant circuit, a second signal extraction circuit, a second processing module, a third driving module, and a second conversion circuit. The first and second resonant circuits are used to transmit high-power energy. The third and fourth resonant circuits are used to realize half-duplex communication and low-power energy transmission between the transmitter and receiver. The first processing module is connected to the first conversion circuit via the first driving module, and the first conversion circuit is connected to the first resonant circuit. The first processing module is connected to the third conversion circuit via the second driving circuit, and the third conversion circuit is connected to the third resonant circuit. The third resonant circuit is connected to the first processing module via the first signal extraction circuit. The second resonant circuit is connected to the second conversion circuit. The second processing module is connected to the fourth resonant circuit via the third driving module. The fourth resonant circuit is connected to the second processing module via the second signal extraction circuit.

[0038] Specifically, the wireless charging system as a whole can participate in... Figure 10 As shown, the main modules include:

[0039] The first and second processing modules are the control core of the entire circuit system, responsible for coordinating and controlling the overall circuit, as well as processing and analyzing relevant signals. These modules can utilize microcontrollers (MCUs), which are characterized by high integration, low cost, and low power consumption. An MCU integrates a processor core, memory, and various peripheral interfaces, meeting the control and signal processing requirements of the circuit. In this wireless charging system, it can be used to control the operating state of each resonant circuit, receive and process communication signals, and coordinate power transmission and communication functions. STMicroelectronics' STM32 series microcontrollers, with their abundant resources and powerful processing capabilities, can efficiently execute complex control tasks and achieve precise control of the wireless charging system.

[0040] Driver module:

[0041] First driving module: Provides driving signals for the power switching transistors (S1-S4) in the first conversion circuit, and controls their turn-on and turn-off.

[0042] The second drive module controls the power switching transistors (S1, S2) in the third conversion circuit.

[0043] The third drive module controls the power switching transistors (S7, S8) in the fourth conversion circuit.

[0044] The first, second, and third drive modules can utilize integrated driver chips. These chips integrate multiple functions, such as drive circuits and protection circuits, and offer advantages such as stable performance, high reliability, and small size. For example, IR's IR2110 integrated driver chip can drive two power devices simultaneously and features a bootstrap circuit, enabling easy driving of both high-end and low-end power devices. When applied to the third drive module, it can directly drive half-bridge or full-bridge inverter circuits (the third and fourth conversion circuits), providing suitable drive signals for the resonant circuit. Its internal protection functions can also prevent abnormal conditions such as overcurrent and overvoltage, ensuring the safe and stable operation of the system.

[0045] Conversion circuit

[0046] The first conversion circuit consists of four power switching transistors S1-S4, which convert the input DC voltage into a high-frequency AC voltage. A common topology is the full-bridge inverter circuit, which is used to invert DC power into AC power so that energy can be transferred through a resonant circuit.

[0047] The second conversion circuit, consisting of power switching transistors S5-S8, converts the high-frequency AC output from the second resonant circuit into the required DC power, thus achieving the conversion from AC to DC.

[0048] The third conversion circuit, consisting of power switching transistors S9 and S10, can convert the input DC voltage into a high-frequency AC signal to cooperate with the third and fourth resonant circuits.

[0049] The fourth conversion circuit consists of power switching transistors S11 and S12, which processes the output of the fourth resonant circuit and converts the AC signal into a DC signal.

[0050] resonant circuit

[0051] The first resonant circuit consists of an inductor L1, a capacitor C1, and a resistor R1. It works in conjunction with the second resonant circuit's L2, C2, R2, and mutual inductance M to achieve wireless energy transmission or efficient energy conversion through electromagnetic induction. It utilizes the principle of resonance to achieve impedance matching and efficient energy transmission at a specific frequency.

[0052] The second resonant circuit, together with the first resonant circuit, forms a resonant coupling structure, enabling the transfer of energy from one side to the other.

[0053] The third resonant circuit consists of L3 and C3, and the fourth resonant circuit consists of L4 and C4. Together with the third and fourth conversion circuits, they can realize signal processing or low-energy transmission functions at specific frequencies.

[0054] Signal extraction circuit

[0055] First signal extraction circuit: Extracts relevant signals from the circuit and feeds them back to the first processing module for monitoring circuit status, implementing closed-loop control, etc., such as extracting voltage and current signals for control and regulation.

[0056] Second signal extraction circuit: Extracts signals and feeds them to the second processing module to monitor and control the circuit output and other states.

[0057] In this embodiment, the first signal extraction circuit and the second signal extraction circuit have the same structure, both including a filtering circuit and a demodulation circuit. The filtering circuit is a common passive filter, see [link to relevant documentation]. Figure 3 or Figure 4 As shown. A demodulation circuit can include rectification, filtering, amplification, and comparison stages. Specifically, a demodulation circuit is as follows: Figure 5 As shown, the circuit includes diodes D1 and D2, resistors R1, R2, R3, R4, R5, R6, R7, R8, and R9, capacitors C1, C2, and C3, an operational amplifier OP, and a comparator COMP. The filtered signal input is connected at one end to the anode of diode D1 and the cathode of diode D2, and the other end is grounded. The cathode of diode D1 is connected to one end of resistor R1, and the anode of diode D2 is connected to one end of resistor R2. The other end of resistor R1 is connected to one end of capacitor C1 and one end of resistor R3. The other end of resistor R2 is connected to one end of capacitor C2 and one end of resistor R5. The other end of capacitor C1 and the other end of capacitor C2 are connected together to one end of resistor R4. The other end of resistor 4, together with the other end of resistor R3, is connected to the non-inverting input of operational amplifier OP; the inverting input of operational amplifier OP is connected to the other end of resistor R5; the output of operational amplifier OP is connected to one end of resistor R6 and one end of resistor R7; the other end of resistor R6 is connected between the inverting input of operational amplifier OP and resistor R5; the other end of resistor R7 is connected to one end of capacitor C3 and one end of resistor R8; the other end of capacitor C3 is grounded; the other end of resistor R8 is connected to one end of resistor R9 and the non-inverting input of comparator COMP, and the other end of resistor R9 is grounded; the inverting input of comparator COMP is connected to the reference voltage, the reference voltage is grounded, and the output of comparator COMP is connected to the processing module.

[0058] The demodulation circuit has the following functions:

[0059] The rectifier section consists of diodes D1 and D2. Utilizing the unidirectional conductivity of diodes, it converts the input AC signal into a unidirectional pulsating DC signal. During the positive half-cycle of the input AC signal, D1 conducts and D2 is cut off; during the negative half-cycle, D2 conducts and D1 is cut off, achieving full-wave rectification.

[0060] The filtering section consists of an RC filter circuit composed of resistors R1 and R2 and capacitors C1 and C2. Capacitors C1 and C2 bypass the AC component in the pulsating DC signal. Through the capacitive reactance characteristic, the AC component returns to ground more through the capacitor, while the DC component passes smoothly. Resistors R1 and R2 are used to limit the current. Together with the capacitors, they smooth the output DC signal.

[0061] The amplification (op-amp) section includes the operational amplifier OP and resistors R3, R4, R5, and R6. This is a non-inverting proportional amplifier circuit. The input signal is input from the non-inverting terminal, amplified, and output from the op-amp output terminal, enhancing the signal amplitude for easier subsequent processing.

[0062] The secondary filtering section consists of an RC filter circuit composed of resistor R7 and capacitor C3, which is used to further filter out high-frequency noise in the signal, making the signal purer and providing a stable input signal for the subsequent comparator.

[0063] The comparison section consists of a comparator COMP and resistors R8 and R9, connected to a reference voltage. The comparator compares the filtered signal with the reference voltage. When the input signal is higher than the reference voltage, the comparator outputs a high level; when the input signal is lower than the reference voltage, the comparator outputs a low level. The high and low level signals (pulse signals) are sent to the processing module for further processing.

[0064] Example 3: In a specific wireless charging system application scenario, assuming it is used for wireless charging of electric vehicles. The first and second resonant circuits use large coils and suitable capacitance and inductance parameters to achieve efficient high-power energy transmission and meet the fast charging requirements of electric vehicles. The third and fourth resonant circuits adopt a series (S) compensation method, and the third and fourth conversion circuits use full-bridge inverter circuits.

[0065] The filtering circuit employs passive filters. The band-stop filter is an LC type, with its center frequency precisely set at the power signal frequency to effectively suppress it. The band-pass filter is a second-order RC band-pass filter, with its center frequency set to the communication carrier signal frequency, allowing the communication signal to pass smoothly. The high-pass filter is a first-order RC high-pass filter, with its cutoff frequency set between the power signal frequency and the communication carrier signal frequency. The demodulation circuit includes rectifier diodes, filter capacitors, an amplifier, and a comparator, converting the filtered signal into a binary sequence signal that the processing module can recognize.

[0066] The power transmission coil and communication coil are orthogonally wound to reduce the impact of power transmission on communication. The carrier signal is provided by the processing module, and the drive module and conversion circuit work together to modulate the communication signal generated by the processing module and transmit it through the resonant circuit. When the transmitter charges the receiver, the transmitter provides auxiliary power to the receiver circuit through the third resonant circuit to the fourth resonant circuit, realizing the self-powering of the wireless charger. When the vehicle battery powers the receiver, the receiver provides auxiliary power to the transmitter circuit through the fourth resonant circuit to the third resonant circuit, waking up the transmitter circuit and disconnecting it from the mains power when not charging, thus reducing power consumption.

[0067] Example 4: In another application scenario, such as wireless charging of multiple small electronic devices, the parameters of the first and second resonant circuits are adjusted according to the device requirements. The third and fourth resonant circuits adopt LCC compensation, and the third and fourth conversion circuits adopt half-bridge inverter circuits.

[0068] The filtering circuit employs an active filter, utilizing operational amplifiers, resistors, and capacitors to form band-stop, high-pass, and band-pass filters, achieving more precise signal selection. The demodulation circuit uses an integrated demodulation chip, simplifying circuit design. The carrier signal is provided by an oscillation generation circuit (such as a 555 timer), generating a stable communication carrier signal. In this configuration, multiple small electronic devices can simultaneously perform wireless charging and communication within a short distance without interfering with each other, improving the efficiency of charging and data transmission.

[0069] As can be seen from the above embodiments, the present invention can be flexibly configured according to different application scenarios and needs, effectively realizing wireless charging and near-field communication functions, and has broad application prospects.

Claims

1. A near-field communication method for a wireless charging system, comprising a transmitting circuit and a receiving circuit, wherein the transmitting circuit includes a first resonant circuit and a third resonant circuit, and the receiving circuit includes a second resonant circuit and a fourth resonant circuit, and both the transmitting and receiving ends are provided with a signal extraction circuit, characterized in that: The near-field communication method includes: High-power energy is transmitted through the first resonant circuit and the second resonant circuit; The third and fourth resonant circuits are used to realize half-duplex communication and low-power energy transmission between the transmitter and receiver. The half-duplex communication is based on near-field coupling, and the power signal is removed by the signal extraction circuit to obtain a clean and effective communication signal. The low-power energy transmission provides auxiliary power to the receiver or transmitter. The third and fourth resonant circuits adopt a series compensation or LCC compensation structure. The coils of the first resonant circuit, the second resonant circuit, the third resonant circuit, and the fourth resonant circuit are orthogonally wound. When the receiver is not connected to a battery, the transmitter transmits a small amount of energy to the fourth resonant circuit through the third resonant circuit as an auxiliary power source for the receiver, thus enabling the wireless charging system to be self-powered. When the receiver is connected to a battery, it transmits a small amount of power to the transmitter through the fourth resonant circuit to provide auxiliary power, thereby waking up the transmitter and disconnecting it from the mains power input in the idle state.

2. The near-field communication method of the wireless charging system according to claim 1, characterized in that: The signal extraction circuit performs signal extraction including: The communication signal and the power signal are filtered by a filtering circuit to remove the power signal. The filtering circuit is one or a combination of a band-stop filter, a high-pass filter, or a band-pass filter. The center frequency of the band-stop filter is set to the power signal frequency, and the center frequency of the band-pass filter is set to the communication carrier frequency. The cutoff frequency of the high-pass filter is set between the power signal frequency and the communication signal frequency. The filtered communication signal is converted into a binary sequence signal by a demodulation circuit.

3. The near-field communication method of the wireless charging system according to claim 2, characterized in that: The filter in the filtering circuit can be a passive or active filter.

4. The near-field communication method of the wireless charging system according to claim 1, characterized in that: The communication signal transmission function is implemented by a processing module, a driving module, and a conversion circuit. The driving module enhances the driving capability of the output signal of the processing module, enabling it to effectively drive the conversion circuit. The conversion circuit is responsible for modulating and amplifying the signal output by the driving module, converting it into a high-frequency AC signal suitable for transmission in a resonant circuit, thereby achieving effective transmission of the communication signal.

5. The near-field communication method of the wireless charging system according to claim 1, characterized in that: The signal extraction circuit includes a filtering circuit and a demodulation circuit; the filtering circuit is a combination of one or more of a band-stop filter, a high-pass filter, and a band-pass filter; the demodulation circuit includes a rectifier module, an amplifier module, and a comparator, used to convert the filtered communication signal into a binary sequence signal after rectification, amplification, and comparison.

6. The near-field communication method of the wireless charging system according to claim 4, characterized in that: The conversion circuit uses a half-bridge or full-bridge inverter circuit to convert DC signals into high-frequency AC signals.

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