WPT System Based on Shielded Capacitor Plate Data Transmission and Its Data Parallel Transmission Method

Abstract

The present invention discloses a WPT system based on data transmission of shielded capacitor plates and its data parallel transmission method. The present invention uses a hybrid data energy separation channel transmission of inductors and shielded capacitor plates. Since there is an independent data transmission channel, there is no need to modulate and demodulate the carrier of power transmission, solving the problem of difficult constant voltage and constant current control of power modulation. Since it is a separated channel transmission, it solves the problem of signal crosstalk during parallel transmission of high-frequency data carrier energy signals. In addition, the proposed two-way data transmission based on shielded capacitor plates in the present invention makes reasonable use of the electromagnetic shielding plate, without adding an additional shielding isolation circuit, greatly reducing the cost and space. By using the impedance characteristics of the circuit itself, it reduces the interference of electric energy on the signal, reduces the complexity of the channel, and ensures that the existence of the signal channel does not affect the transmission power of the system.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronics, and particularly relates to a WPT system based on shielded capacitor plate data transmission and a data parallel transmission method thereof. Background Art

[0002] With the improvement of the power and frequency of the wireless power transmission system, in order to improve the power transmission efficiency and the anti-interference ability of the system, real-time data interaction is required between the power transmitting end and the receiving end of the wireless power transmission. Currently, the following are several common ways of shared-channel energy data parallel transmission:

[0003] 1. The energy data parallel transmission method based on power modulation: Modulate the voltage amplitude of the power transmitting end according to different digital signals to be transmitted, and finally realize the demodulation of the digital signal by detecting the output voltage amplitude at the pickup end. Since the direct modulation of the signal is in the power channel, it is relatively difficult to perform constant voltage and constant current control, and it is difficult to ensure the integrity of the signal during the constant voltage and constant current control process.

[0004] 2. The shared-channel energy data parallel transmission based on high-frequency data carriers: Inject the modulation signal into the common channel in a frequency division multiplexing manner, use the fundamental component to transmit power, and use the higher-order components to transmit data. Enable the high-frequency carrier and the power to be transmitted through the same coupling mechanism at the same time. The signal transmission rate is relatively high. However, when the selected harmonic is designed to be zero or a certain value by changing the duty cycle or phase shift angle of the inverter, other order harmonics still exist, which has a significant impact on signal extraction and further increases the demodulation difficulty.

[0005] 3. The separated-channel energy data parallel transmission with multiple inductance channels: Since the separated channel needs to add additional inductance coils to transmit signals, it physically reduces the crosstalk between the power and the signal. However, the cost and space increase caused by adding coils limit its application scenarios. And in the case where two independent coils receive power and data signals respectively, the cross-coupling between the power receiving coil and the data receiving coil may cause a certain amount of crosstalk.

[0006] For the above-mentioned common shared-channel energy data parallel transmission, only one channel is required to transmit power and signals, and the signal transmission rate is relatively high. However, the crosstalk problem of power transmission on signal transmission is difficult to solve, and additional isolation circuits and control algorithms need to be added to solve the crosstalk problem, which increases the circuit complexity and design difficulty; while the separated-channel energy data parallel transmission physically reduces the crosstalk between the power and the signal, but the additional data channel increases the cost of the system.

[0007] In the prior art, data is modulated and transmitted through a high-frequency electric field generated by the parasitic capacitance of a coupling coil and a metal shielding plate, while power is transmitted through a relatively low-frequency magnetic field generated by the coupling coil. Compared with traditional methods, this method does not require additional coils, and because power is transmitted through the magnetic field and data is transmitted through the electric field, band-pass filters are easy to design. Experimental results show that the data transmission channel has little impact on power transmission, and it has advantages such as good flexibility and large redundancy for spatial position offset.

[0008] However, the data transmission link in the prior art is constructed by the parasitic capacitance of an aluminum plate and a coil. In this case, the multiplexing of the coil inductance and capacitance characteristics makes the power and data transmission channels not fully decoupled, and data passes through part of the power transmission circuit, inevitably leading to complex parameter design and relatively low signal quality. In terms of foreign object detection, when a metal foreign object appears in the energy transmission channel, although it does not affect the signal transmission of the aluminum plate electric field, it will still affect the parasitic capacitance of the inductance coil to a certain extent. The voltage disturbance of the load caused by the foreign object cannot be quickly fed back to the sending end through the coupled electric field signal channel generated by the parasitic capacitance of the aluminum plate and the coil. It is necessary to add detection devices on the primary and secondary sides of the coil inductance and then decide whether to stop the power transmission. The detection speed is slow, and in an emergency, the inverter cannot be stopped immediately. In addition, in an emergency, such as when the coil is burned out, an alarm message should be sent immediately to stop the power transmission, which is a difficult-to-solve drawback for data transmission methods relying on coils. Summary of the Invention

[0009] To solve the above problems, the present invention provides a WPT system based on shielded capacitor plates for data transmission and its data parallel transmission method. In order to reduce costs, mutual crosstalk between power transmission and signal transmission, and the complexity of the signal channel, the present invention proposes to use the shielded capacitor plates for bidirectional data transmission, reasonably utilize the electromagnetic shielding plate, without adding an additional shielding isolation circuit, greatly reducing costs and space. By using the impedance characteristics of the circuit itself, it reduces the interference of electric energy on the signal, reduces the complexity of the channel, and ensures that the existence of the signal channel does not affect the system transmission power.

[0010] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0011] The present invention provides a WPT system based on data transmission of a shielded capacitor plate. The system adds a signal transmission path using a shielded capacitor plate to the original WPT system that uses a coupling coil to transfer energy. The WPT system includes two channels: power transmission and signal transmission. Among them, the signal transmission channel uses a four-resonant double-suppression structure to achieve full-duplex communication. Two data carriers are transmitted through an equivalent SS compensation structure formed by a parallel LC resonant network and a serial LC resonant network. The parallel LC resonant network is used to block one carrier while transmitting the other carrier, and the serial LC resonant network is used to compensate for the reactive power of the circuit and improve the transmission power of the capacitor plate. The forward and reverse signals are injected into the shielded capacitor plate through a wave-blocking resonant network and a resonant inductor, forming a high-frequency alternating potential difference on the shielded capacitor plate, generating a high-frequency electric field and exciting an alternating voltage on the shielded capacitor plate to form an interactive electric field. Under the action of the interactive electric field, a displacement current "flows through" the shielded capacitor plate, and the two data carriers are transmitted to the shielded capacitor plate of the WPT system.

[0012] In one embodiment, the power transmission channel is specifically: the input DC power supply Vin passes through a full-bridge inverter circuit composed of four switching tubes to generate a sine wave with a frequency of ω 0 . The power transmission part adopts an equivalent SS compensation structure. C P and C S are the compensation capacitors of the primary side transmitting coil L P and the secondary side receiving coil L S to eliminate the self-inductance of the coil. The secondary side of the power transmission is rectified by diodes D 1 ~D 4 without control to supply power to the load R L .

[0013] The signal transmission channel is specifically:

[0014] To perform full-duplex transmission of signals, two signal sources U 1 and U 2 are respectively set on the primary side and the secondary side of the signal transmission circuit to simulate signal input. The forward digital signal Date1 in and the reverse digital signal Date2in are modulated with a sine wave of a specified frequency through ASK modulation and then injected into the signal transmission channel using a power amplifier.

[0015] The primary side transmitting coil Lp and the secondary side receiving coil Ls are respectively located inside the shielded capacitor plate. C S1 , C S2 are the equivalent mutual capacitances of the shielded capacitor plate. C P12 and C P34 are respectively the equivalent self-capacitances of the transmitting end and the receiving end of the shielded capacitor plate.

[0016] To demodulate the forward and reverse signals and place the sine carriers of the forward and reverse signals in different frequency bands, the carrier frequency of the forward signal is set to ω 1 , and the carrier frequency of the reverse signal is ω 2 ;

[0017] The forward signal is injected into the primary shielding capacitor plate through the blocking resonant network L 1 C 1 and the primary resonant inductor Lpp. The secondary shielding capacitor plate then passes through the secondary resonant inductor Lss and the blocking resonant network L 3 , C 3 to obtain a signal waveform at the sampling resistor R 2 ; After sampling the signal waveform from R 2 , the signal waveform is half-wave rectified into a signal waveform containing only the positive half-axis, the noise outside the passband is filtered out by an RC filter, and the filtered waveform is amplified by an operational amplifier and sent to envelope detection. The detected envelope signal is compared with a given value to obtain a digital signal;

[0018] The reverse signal passes through L 4 C 4 the blocking network and the secondary resonant inductor Lss and is injected into the secondary shielding capacitor plate, and then the signal is transmitted to the primary shielding capacitor plate through displacement current, and through the primary resonant inductor Lpp and the blocking resonant network L 2 C 2 it is transmitted to the sampling resistor R 1 to obtain a signal waveform. After sampling the signal waveform from R 1 , the signal waveform is half-wave rectified into a signal waveform containing only the positive half-axis, the noise outside the passband is filtered out by an RC filter, and the filtered waveform is amplified by an operational amplifier and sent to envelope detection. The detected envelope signal is compared with a given value to obtain a digital signal.

[0019] In one embodiment, the primary transmitting coil Lp, the secondary receiving coil Ls, and their compensation capacitors C P and C S need to satisfy the following formula:

[0020]

[0021] where ω 0 is the angular frequency of the sine wave generated by the full-bridge inverter circuit composed of four switching tubes for the input DC power supply Vin; f 0 is the frequency corresponding to the angular frequency ω 0 ; L P is the inductance of the primary transmitting coil, C P is the capacitance value of the primary compensation capacitor; L S is the inductance of the secondary receiving coil, and C S is the capacitance value of the secondary compensation capacitor.

[0022] In one embodiment, the topological structure of the shielding capacitor plates adopts a parallel disk coupling structure, specifically:

[0023] The transmitting end P of the shielding capacitor plates 1 , P 2 and the receiving end P 3 , P 4 adopt a parallel disk coupling structure. C S1 is the equivalent mutual capacitance between P 1 , P 3 , and C S2 is the equivalent mutual capacitance between P 2 , P 4 . C P12 and C P34 are respectively the equivalent self-capacitances of the transmitting end and the receiving end of the parallel shielding capacitor plates.

[0024] In one embodiment, the geometric parameters of the WPT system include the coil and metal shielding plate sizes, and the metal shielding plate size is obtained through finite element analysis of the optimization function in the ANSYS software after the coil is determined.

[0025] In one embodiment, for the primary transmitting coil and the secondary receiving coil, the radius R = 57 mm, the outer radius R1 of the inner shielding capacitor plate P 2 is 40.5 mm, the radius R2 of the outer shielding capacitor plate P 1 is 72.3 mm, the difference lg between the inner diameter of the outer shielding capacitor plate P 1 and the radius of the inner shielding capacitor plate P 2 is 1 mm, and the parasitic capacitance difference between the coil and the shielding capacitor plates is almost zero, that is, the parasitic capacitance between the primary transmitting coil L P and the outer shielding capacitor plate P 3 , the inner shielding capacitor plate P 4 of the secondary is the same, and the parasitic capacitance between the secondary receiving coil L S and the outer shielding capacitor plate P 1 , the inner shielding capacitor plate P 2 of the primary is the same.

[0026] In one embodiment, the parallel LC resonant network is composed of four groups of parallel resonant networks, and the four groups of parallel resonant networks are respectively the parallel network of the resonant inductor L 1 and the resonant capacitor C 1 , the parallel network of the resonant inductor L 2 and the resonant capacitor C 2 , the parallel network of the resonant inductor L 3 and the resonant capacitor C 3 , the parallel network of the resonant inductor L 4With the resonant capacitor C 4 The parallel network is formed; L 1 C 1 The parallel network and L 3 C 3 The parallel network are at the same resonant frequency, L 2 C 2 The parallel network and L 4 C 4 The parallel network are at the same resonant frequency; that is, the resonant point of the forward LC network is exactly the suppression point of the reverse LC network; the serial LC resonant network is composed of the compensation inductor L PP and L SS and the equivalent mutual capacitance C S1 and C S2 constitute; through the equivalent SS compensation structure, two signal sources can be applied to the WPT system at the same time, so as to realize full-duplex communication.

[0027] In one embodiment, the method for setting the frequency of the forward signal carrier and the frequency of the reverse signal carrier is as follows:

[0028] Set the forward transmission carrier frequency as ω 1 , and the reverse transmission carrier frequency as ω 2 , and adjust the resonant point at the ω 1 frequency to the suppression point (maximum impedance) at the ω 2 frequency, and adjust the resonant point at the ω 2 frequency to the suppression point at the ω 1 frequency, so that a resonant point of one LC resonant network is exactly the suppression point of the other LC resonant network.

[0029] In one embodiment, the selection process of the equivalent SS compensation structure is as follows:

[0030] Equivalent the full-duplex communication channel topology to the CPT system circuit structure with equivalent SS compensation, and derive the input impedance;

[0031] When the system is in the resonant state and the input impedance Zin is purely resistive, set the compensation inductor L 1 and L 2 The constraint conditions to be satisfied;

[0032] Set the frequency of the forward signal carrier and the frequency of the reverse signal carrier, and adjust the resonant point at the ω 1 frequency to the suppression point (maximum impedance) at the ω 2 frequency, and adjust the resonant point at the ω 2 frequency to the suppression point at the ω 1 frequency, that is, the resonant point of the forward LC resonant network is exactly the suppression point of the reverse LC resonant network;

[0033] L 1 C 1 The network of L 3 C 3 needs to be in parallel resonance at the reverse carrier frequency ω 2 ;

[0034] L 2 C 2 The network of L 4 C 4 needs to be in parallel resonance at the forward carrier frequency ω 1 ;

[0035] When transmitting the forward signal, simplify the signal transmission network:

[0036] Equivalent the resonant network of L 1 C 1 and the compensation inductor L pp to the equivalent inductor L eq1 ;

[0037] Equivalent the resonant network of L 3 C 3 and the compensation inductor L ss to the equivalent inductor L eq2 ;

[0038] When the inductance value of L eq1 and the inductance value of L eq2 meet the constraint condition of L 1 and L 2 the system is in the resonant state;

[0039] Similarly, when transmitting the reverse signal, simplify the signal transmission network:

[0040] Equivalent the resonant network of L 2 C 2 and the compensation inductor L pp to the equivalent inductor L eq3 ,

[0041] Equivalent the resonant network of L 4 C 4 and the compensation inductor L ss to the equivalent inductor L eq4 ;

[0042] When the inductance value of L eq3 and the inductance value of L eq4 meet the constraint condition of L 1 and L 2 the system is in the resonant state. Design the resonant network of L 1 C 1 , L 3 C 3 , L 2C 2 ,L 4 C 4 and L pp and L ss value of

[0043] The present invention also provides a data parallel transmission method for a WPT system based on shielded capacitor plate data transmission. The method includes: adopting the amplitude shift keying (ASK) method to change the amplitude of the carrier wave according to different digital signals. The 01 digital signal sent by the host computer is converted into an analog signal with voltage through a DA conversion module, and then modulated with a sine carrier wave of the rated frequency by using ASK modulation. When the analog signal is a high voltage, the ASK modulation outputs a carrier wave amplitude of A1 representing the digital signal 1, and when the analog signal is a low voltage, the ASK modulation module outputs a carrier wave amplitude of A0 representing the digital signal 0 to achieve signal modulation; then, after passing through a proportional amplification circuit, signal carriers with different amplitudes are output;

[0044] On the receiving side, after half-wave rectification, the modulated carrier wave is obtained through an RC filter, and the envelope wave of the carrier signal is obtained by using non-coherent envelope detection to achieve demodulation of the carrier signal;

[0045] Finally, the comparator compares the envelope wave with a given voltage signal. When the envelope wave is greater than the comparison voltage, the comparator outputs 1, and when it is less than the comparison voltage, the comparator outputs 0. Thus, the analog signal is converted into a digital signal.

[0046] In one embodiment, the process of obtaining the carrier signal through envelope wave demodulation includes:

[0047] The input carrier passes through a detection diode to obtain a positive half-cycle waveform. Through an RC parallel network, by changing the values of the resistor R and the capacitor C, the charge and discharge constant τ is adjusted to obtain the carrier signal of the waveform; the design of the RC parameters needs to meet two conditions: first, it should be ensured that the discharge speed of the capacitor C is slower than the voltage drop speed of a single-cycle carrier wave; second, it is required that the capacitor discharge time should be shorter than half of the time occupied by one digital signal in the carrier wave.

[0048] Advantages of the present invention:

[0049] The present invention uses a hybrid data energy separation channel transmission of inductance and shielded capacitor plates. Since there is an independent data transmission channel, there is no need to modulate and demodulate the carrier wave of power transmission anymore, solving the problem of difficult constant voltage and constant current control in power modulation. Since it is a separation channel transmission, it solves the problem of signal crosstalk during parallel transmission of high-frequency data carrier energy signals. Since an electromagnetic shielding metal plate is used as the capacitive path for signal transmission, there is no need to additionally increase inductance, solving the problems of high cost and large space in the multi-inductance separation channel type. Description of the Drawings

[0050] The accompanying drawings, as part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the accompanying drawings in the following description are only some embodiments, and those of ordinary skill in the art can obtain other accompanying drawings based on these accompanying drawings without creative efforts.

[0051] Figure 1 Schematic diagram of a WPT system based on shielded capacitor plate data transmission provided for an embodiment of the invention;

[0052] Figure 2 Parallel disk coupling structure diagram provided for an embodiment of the present invention;

[0053] Figure 3 Metal cross-section design diagram provided for an embodiment of the present invention;

[0054] Figure 4 Electric field strength analysis diagram provided for an embodiment of the invention;

[0055] Figure 5 Coupling mechanism model diagram provided for an embodiment of the invention;

[0056] Figure 6 Full-duplex communication channel topology structure diagram provided for an embodiment of the invention;

[0057] Figure 7 CPT system circuit structure diagram with SS compensation provided for an embodiment of the invention;

[0058] Figure 8 Dual-channel frequency characteristic curve provided for an embodiment of the invention;

[0059] Figure 9 Forward signal transmission equivalent circuit model provided for an embodiment of the invention;

[0060] Figure 10 Reverse signal transmission equivalent circuit model provided for an embodiment of the invention;

[0061] Figure 11 Signal carrier waveform diagram after ASK modulation provided for an embodiment of the invention;

[0062] Figure 12 Principle diagram of envelope detection provided for an embodiment of the invention;

[0063] Figure 13 Simulation circuit model diagram provided for an embodiment of the invention;

[0064] Figure 14 Bidirectional signal transmission waveform diagram provided for an embodiment of the invention;

[0065] Figure 15 It is the signal diagram of the signal transmission and sampling resistor provided in the invention embodiment;

[0066] Figure 16 It is the signal diagram of half-wave rectification and RC-filtered signal provided in the invention embodiment;

[0067] Figure 17 It is the signal diagram of envelope detection and comparator output provided in the invention embodiment.

[0068] It should be noted that these drawings and textual descriptions are not intended to limit the scope of the concept of the present invention in any way, but to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0069] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0070] The following are the corresponding explanations for the above-mentioned terms.

[0071] WPT system: The wireless power transfer (WPT) system refers to the energy transfer between the transmitting and receiving units. Generally, inductance coils or capacitive substrates are used to replace traditional power transmission lines to complete wireless power transfer within a certain distance.

[0072] ECPT system: The electric-field coupled power transfer (ECPT) is a wireless power transfer technology that uses metal plates as the coupling mechanism and high-frequency electric fields as the energy transfer medium.

[0073] ICPT system: The inductive coupled power transfer (ICPT) transfers energy from the transmitting end to the receiving end through the principle of electromagnetic induction. It is based on Faraday's law of electromagnetic induction and uses a changing magnetic field to generate current between two electromagnetic induction coils, thereby realizing energy transfer.

[0074] Shielding capacitor plate: Since the wireless power transfer system will generate large magnetic and electric field leaks, which are harmful to organisms, a shielding layer needs to be added at both ends of the power transfer coil. The shielding layer is generally a metal plate and can be regarded as a capacitor.

[0075] Crosstalk: Noise caused by mutual inductance and mutual capacitance between two transmission lines when energy is transmitted simultaneously with a signal.

[0076] An embodiment of the present invention provides a WPT system based on data transmission using a shielded capacitor plate. Referring to Figure 1 as shown, this system adds a signal transmission path using a shielded capacitor plate to the original WPT system that uses a coupling coil to transfer energy; the WPT system includes two channels for power transmission and signal transmission. Among them, the signal transmission channel uses a four-resonant double-suppression structure to achieve full-duplex communication, and two data carriers are transmitted through an equivalent SS compensation structure formed by a parallel LC resonant network and a serial LC resonant network; the parallel LC resonant network is used to block one carrier while transmitting the other carrier, and the serial LC resonant network is used to compensate the reactive power of the circuit and improve the transmission power of the shielded capacitor plate; the forward and reverse signals are injected into the shielded capacitor plate through a wave-blocking resonant network and a resonant inductor, forming a high-frequency alternating potential difference on the shielded capacitor plate, generating a high-frequency electric field and exciting an alternating voltage on the shielded capacitor plate to form an interactive electric field; under the action of the interactive electric field, a displacement current "flows through" the shielded capacitor plate, and the two data carriers are transmitted to the shielded capacitor plate of the WPT system.

[0077] Continuing to refer to Figure 1 as shown, this system is divided into two channels for power transmission and signal transmission. In the power transmission channel, the input DC power supply Vin passes through a full-bridge inverter circuit composed of four switching tubes to generate a sine wave with a frequency of ω 0 For the purpose of intuitively describing the transmission mechanism of the signal part, only the SS compensation structure is adopted for the power transmission part. C P and C S are the compensation capacitors for the primary side transmitting coil L P and the secondary side receiving coil L S to eliminate the self-inductance of the coil, so that the compensation network and the coil work in a resonant state, reducing the reactive power of the coil and improving the transmission efficiency of the system. The secondary side of the power transmission is rectified by diodes D 1 ~D 4 uncontrolled to supply power to the load R L .

[0078] In the signal transmission channel, for full-duplex transmission of signals, two signal sources U 1 and U 2 are respectively set at the primary side and the secondary side of the signal transmission circuit to simulate signal input. The forward digital signal Date1 in and the reverse digital signal Date2in are modulated with a sine wave of a specified frequency through ASK modulation, and then injected into the signal transmission channel by using a power amplifier;

[0079] The primary side transmitting coil Lp and the secondary side receiving coil Ls are respectively located inside the shielding capacitor plates, C S1 and C S2 are the equivalent mutual capacitances of the shielding capacitor plates, and C P12 and C P34 are the equivalent self - capacitances of the transmitting end and the receiving end of the shielding capacitor plates respectively;

[0080] In order to demodulate the forward and reverse signals, the sine carriers of the forward and reverse signals need to be in different frequency bands. Set the carrier frequency of the forward signal to ω 1 , and the carrier frequency of the reverse signal to ω 2 ;

[0081] The forward signal is injected into the primary side shielding capacitor plates through the wave - blocking resonant network L 1 , C 1 and the primary side resonant inductor Lpp. By forming a high - frequency alternating potential difference on the primary side shielding capacitor plates, this potential difference excites a high - frequency electric field and induces an alternating voltage on the secondary side shielding capacitor plates, forming an interactive electric field. Under the action of the interactive electric field, a displacement current "flows through" the shielding capacitor plates, transferring the two data carriers to the secondary side shielding capacitor plates of the system; the secondary side shielding capacitor plates then pass through the secondary side resonant inductor Lss and the wave - blocking resonant network L 3 , C 3 to obtain the signal waveform on the sampling resistor R 2 ; after sampling the signal waveform from R 2 , it is half - wave rectified into a signal waveform containing only the positive half - axis, the noise outside the passband is filtered by an RC filter, and the filtered waveform is amplified by an operational amplifier and sent to envelope detection. The detected envelope signal is compared with a given value to obtain a digital signal;

[0082] The reverse signal transmission is the same in principle. The reverse signal is injected into the secondary side shielding capacitor plates through the L 4 C 4 wave - blocking network and the secondary side resonant inductor Lss, and then the signal is transmitted to the primary side shielding capacitor plates through the displacement current, and is transmitted to the sampling resistor R 2 C 2 through the primary side resonant inductor Lpp and the wave - blocking resonant network L 1 . The signal waveform sampled by R 1 is output as a complete digital signal through half - wave rectification, RC filtering, operational amplifier, envelope detection, and comparator.

[0083] Furthermore, the primary side transmitting coil Lp, the secondary side receiving coil Ls and their compensation capacitors C P and C S need to satisfy the following formula:

[0084]

[0085] Among them, ω 0 is the angular frequency of the sine wave generated by the full-bridge inverter circuit composed of four switching tubes for the input DC power supply Vin; f 0 is the frequency corresponding to the angular frequency ω 0 ; L P is the inductance of the primary emission coil, and C P is the capacitance value of the primary compensation capacitor; L S is the inductance of the secondary receiving coil, and C S is the capacitance value of the secondary compensation capacitor.

[0086] Furthermore, the topological structure of the shielding capacitor plates adopts a parallel disk coupling structure, specifically:

[0087] The emitting ends P 1 , P 2 of the shielding capacitor plates and the receiving ends P 3 , P 4 adopt a parallel disk coupling structure. The primary coil Lp and the secondary coil Ls are respectively located inside the shielding capacitor plates, as Figure 2 shown, where C S1 is the equivalent mutual capacitance between P 1 , P 3 , C S2 is the equivalent mutual capacitance between P 2 , P 4 , and C P12 and C P34 are respectively the equivalent self-capacitances of the emitting end and the receiving end of the parallel shielding capacitor plates.

[0088] The size of the parasitic capacitance in the data transmission channel is closely related to the size of the coupling structure. However, the geometric parameters of the existing WPT system, including the coil and metal shielding plate sizes, are mainly determined when analyzing the power transmission channel and specific application scenarios. Therefore, the design of the metal plate division method is a key factor affecting the data transmission performance and magnetic shielding function.

[0089] In the ICPT system, due to electromagnetic shielding, metal obstacles will block the energy transmission. In the ECPT system, the form of energy transmission is an interactive electric field. The energy transmission will not be blocked by metal obstacles, but the metal obstacles are used as part of the shielding capacitor plates to complete the energy transmission. Therefore, the electric energy transmission channel between the shielding capacitor plates will not affect its signal transmission ability, and there is no crosstalk between electric energy and signals. At the same time, the electric field is basically confined to exist between the shielding capacitor plates, and the electromagnetic interference in the system is greatly reduced.

[0090] Further, the geometric parameters of the WPT system include the coil and metal shield plate sizes. After determining the coil, the metal shield plate size is obtained through the finite element analysis of the optimization function in the ANSYS software.

[0091] The metal cross-section is as Figure 3 shown. For the primary transmitting coil and the secondary receiving coil with a radius R = 57 mm, when the outer radius R1 of the inner shield capacitor plate is 40.5 mm, the radius R2 of the outer shield capacitor plate is 72.3 mm, and the difference lg between the inner diameter of the outer shield capacitor plate and the radius of the inner shield capacitor plate is 1 mm, the parasitic capacitance difference between the coil and the shield capacitor plate is almost zero, that is, the parasitic capacitance between the primary transmitting coil L P and the shield capacitor plate P 3 (outer shield capacitor plate), P 4 (inner shield capacitor plate) is the same. The parasitic capacitance between the secondary receiving coil L S and the shield capacitor plate P 1 (outer shield capacitor plate), P 2 (inner shield capacitor plate) is the same. In this way, the crosstalk between power and data transmission can be significantly minimized. At this time, the electric field intensity in the 400 mm × 400 mm area above the metal plate is as Figure 4 shown, and the simulation coupling model is as Figure 5 shown.

[0092] In the data transmission channel, two data carriers are transmitted through an equivalent SS compensation structure formed by a parallel LC resonance network and a serial LC resonance network. Among them, the parallel LC resonance network is composed of four groups of parallel resonance networks, namely the parallel network of resonance inductor L 1 and resonance capacitor C 1 , the parallel network of resonance inductor L 2 and resonance capacitor C 2 , the parallel network of resonance inductor L 3 and resonance capacitor C 3 , the parallel network of resonance inductor L 4 and resonance capacitor C 4 . Among them, the L 1 C 1 parallel network and the L 3 C 3 parallel network are at the same resonance frequency, and the L 2 C 2 parallel network and the L 4 C 4 parallel network are at the same resonance frequency; that is, the resonance point of the forward L C network is exactly the suppression point of the reverse LC resonance network. The parallel LC resonance network is used to block one carrier while transmitting another carrier. The compensation inductor LPP and L SS and the equivalent mutual capacitance C S1 with C S2 constitute a serial L C resonant network for compensating the reactive power of the circuit and improving the transmission power of the shielding capacitor plates.

[0093] By forming a high-frequency alternating potential difference on the shielding capacitor plates, this potential difference excites a high-frequency electric field and induces an alternating voltage on the shielding capacitor plates, forming an interactive electric field. Under the action of the interactive electric field, a displacement current "flows through" the shielding capacitor plates, transmitting two data carriers to the receiving side of the system. Through the proposed topological structure, two signal sources can be applied to the system simultaneously, thus realizing full-duplex communication. Full-duplex communication does not require direction switching, so there is no time delay caused by switching operations, which is very beneficial for application scenarios that require strict consideration of communication delay. The full-duplex communication channel topological structure is as Figure 6 shown.

[0094] Regarding the selection of the SS compensation network in the present invention, the above signal channel can be equivalently regarded as Figure 7 , and the selection process of the equivalent SS compensation structure is as follows:

[0095] Equivalently regard the full-duplex communication channel topology as a CPT system circuit structure with equivalent SS compensation, and derive the input impedance;

[0096] When the system is in the resonant state and the input impedance Zin is purely resistive, set the compensation inductance L 1 and L 2 constraint conditions to be satisfied;

[0097] Set the frequencies of the forward signal carrier and the reverse signal carrier, and adjust the resonance point at the frequency of ω 1 to the suppression point (maximum impedance) at the frequency of ω 2 , and adjust the resonance point at the frequency of ω 2 to the suppression point at the frequency of ω 1 , that is, the resonance point of the forward LC resonant network is exactly the suppression point of the reverse LC resonant network;

[0098] L 1 C 1 network and L 3 C 3 network need to be in parallel resonance at the reverse carrier frequency ω 2 ;

[0099] L 2 C 2 network and L 4 C 4 network need to be in parallel resonance at the forward carrier frequency ω 1Parallel resonance below;

[0100] When the forward signal is transmitted, simplify the signal transmission network:

[0101] Equivalent the resonant network L 1 , C 1 and the compensation inductor L pp to an equivalent inductor L eq1 ;

[0102] Equivalent the resonant network L 3 , C 3 and the compensation inductor L ss to an equivalent inductor L eq2 ;

[0103] When the inductance value of L eq1 and the inductance value of L eq2 satisfy the constraint condition of L 1 and L 2 , the system is in a resonant state;

[0104] Similarly for reverse signal transmission, simplify the signal transmission network:

[0105] Equivalent the resonant network L 2 C 2 and the compensation inductor L pp to an equivalent inductor L eq3 ,

[0106] Equivalent the resonant network L 4 C 4 and the compensation inductor L ss to an equivalent inductor L eq4 ;

[0107] When the inductance value of L eq3 and the inductance value of L eq4 satisfy the constraint condition of L 1 and L 2 , the system is in a resonant state. Design the resonant network L 1 C 1 , L 3 C 3 , L 2 C 2 , L 4 C 4 and L pp and L ss values.

[0108] Specifically, equivalent the full-duplex communication channel topology to a CPT system circuit with equivalent SS compensation. C P12 and C P34 are the equivalent self-capacitances of the transmitter and receiver, C Sis the equivalent mutual capacitance. Among them, the input impedance Z can be obtained through derivation in as follows:

[0109]

[0110] When the system is in the resonant state, the input impedance Z in is purely resistive. At this time, the compensation inductors L 1 and L 2 need to satisfy the following constraint conditions:

[0111]

[0112] For signal transmission, only when the frequency of the forward signal carrier is different from that of the reverse signal carrier, it is possible to achieve that the LC resonant network blocks the carrier in one direction while transmitting a carrier in the other direction, reducing the crosstalk between signals. The specific frequency design method is as follows:

[0113] Set the forward transmission carrier frequency as ω 1 , and the reverse transmission carrier frequency as ω 2 . The frequency responses of the two carriers are as Figure 8 shown. Since the signal transmission channel is composed of a parallel LC resonant network connected to a series LC resonant network, there will be two resonant points at each frequency. In order to transmit two data carriers simultaneously, adjust the resonant point at the ω 1 frequency to the suppression point (maximum impedance) at the ω 2 frequency, and adjust the resonant point at the ω 2 frequency to the suppression point at the ω 1 frequency, which means that a resonant point of one LC resonant network is exactly the suppression point of another LC resonant network.

[0114] The forward signal transmission channel of the above system consists of L 2 / / C 2 , L PP , C S1 , C S2 , L SS , L 4 / / C 4 , R 2 components. The reverse signal transmission channel consists of L 3 / / C 3 , L SS , C S1 , C S2 , L PP , L 1 / / C 1 , R 1 components. The relationship between the frequency and L, C needs to satisfy:

[0115]

[0116] When the signal is transmitted forward, according to the superposition theorem, at ω 1 frequency, when the modulation signal source U 1 works alone, the signal source U 2 and the LC parallel network in series with it are regarded as open circuits, and the signal is sampled and demodulated through R 2 to obtain a digital signal. At this time, the equivalent circuit of signal transmission is as shown in Figure 9 :

[0117] Where: L eq1 is the equivalent inductance of the series connection of the primary-side compensation inductor L PP and the parallel network of L 1 C 1 .

[0118] L eq2 is the equivalent inductance of the series connection of the secondary-side compensation inductor L SS and the parallel network of L 3 C 3 .

[0119]

[0120] When the signal is transmitted backward, at ω 2 frequency, when the modulation signal source U 1 works alone, the signal source U 2 and the LC parallel network in series with it are regarded as open circuits, and the signal is sampled and demodulated through R 1 to obtain a digital signal. At this time, the equivalent circuit of signal transmission is as shown in Figure 10 :

[0121] Where: L eq3 is the equivalent inductance of the series connection of the primary-side compensation inductor L PP and the parallel network of L 2 C 2 .

[0122] L eq4 is the equivalent inductance of the series connection of the secondary-side compensation inductor L SS and the parallel network of L 4 C 4 .

[0123]

[0124] Above, through the model derivation of the above equivalent circuit, the specific parameters of the wave-blocking network and the compensation structure can be designed and topologically structured.

[0125] Regarding the generation of signals, the modulation strategy of the signals in this design adopts the amplitude shift keying (ASK) method, where the amplitude of the carrier is changed according to different digital signals. For binary digital signals, the carrier amplitude A1 represents the digital signal 1, and the carrier amplitude A2 represents the digital signal 0. The waveform diagram of the carrier of the signal after ASK modulation is as Figure 11 shown.

[0126] An embodiment of the present invention provides a data parallel transmission method for a WPT system based on shielded capacitor plate data transmission. The method includes: adopting the amplitude shift keying (ASK) method to change the amplitude of the carrier according to different digital signals. The 01 digital signal sent by the host computer is converted into an analog signal with voltage through a DA conversion module, and then it is modulated with a sinusoidal carrier of the rated frequency by using ASK modulation. When the analog signal is a high voltage, the ASK modulation outputs a carrier amplitude of A1 representing the digital signal 1, and when the analog signal is a low voltage, the ASK modulation outputs a carrier amplitude of A0 representing the digital signal 0 to achieve signal modulation; then, after passing through a proportional amplification circuit, signal carriers with different amplitudes are output;

[0127] On the receiving side, first, after half-wave rectification, the modulated carrier is obtained through an RC filter, and the envelope wave of the carrier signal is obtained by using non-coherent envelope detection to achieve the demodulation of the carrier signal;

[0128] Finally, through a comparator, the envelope wave is compared with a given voltage signal. When the envelope wave is greater than the comparison voltage, the comparator outputs 1, and when it is less than the comparison voltage, the comparator outputs 0. Thus, the analog signal is converted into a digital signal.

[0129] Furthermore, the process of obtaining the carrier signal through envelope wave demodulation includes: the input carrier passes through a detection diode to obtain the waveform of the positive half cycle, and through an RC parallel network, by changing the values of the resistor R and the capacitor C, the charge and discharge constant τ is adjusted to obtain the carrier signal of the waveform. Among them, the design of the RC parameters needs to meet two conditions: first, it should be ensured that the discharge speed of the capacitor C is slower than the voltage drop speed of a single-cycle carrier; second, it is required that the discharge time of the capacitor should be shorter than half of the time occupied by one digital signal in the carrier. The principle of envelope detection is referred to Figure 12 shown.

[0130] In order to analyze the influence of the addition of the signal loop on power transmission and at the same time verify the correctness of the foregoing theoretical analysis of power crosstalk and signal attenuation, to prove the feasibility of the proposed method at the simulation level. A simulation model of the signal transmission path of the system is established on the Simulink platform of Matlab, as Figure 13As shown. The energy transmission part consists of a full-bridge inverter circuit, a resonant network, a signal transmission loop, and an equivalent load resistance. The signal transmission circuit mainly consists of an ASK signal transmitting module, a compensation network, a signal transmission loop, and a signal receiving and demodulating module.

[0131] The digital signal selected in the simulation is a square wave, and the digital signal "1110101010110......" is continuously sent. The signal square wave in the simulation is 315 MHz, and relatively fast text information transmission can already be achieved in serial communication. In the signal modulation part of the figure, the output waveform is determined by the digital signal. When the digital signal is 1, the output peak value is 5V, and when the digital signal is 0, the output is 0V, realizing binary ASK modulation. The detection voltage is the voltage across the load to be detected. The signal receiving part from left to right is respectively half-wave rectification, RC filtering, envelope detection, and the output waveform of the comparator. Among them, the bidirectional signal transmission waveform is as Figure 14 shown, and the signals of the signal transmitter and the sampling resistor are as Figure 15 shown, the signals after half-wave rectification and RC filtering are as Figure 16 shown, and the received signals after envelope detection and comparator output are as Figure 17 shown. It can be seen from the simulation results that the output waveform of the comparator follows the modulation output, completing the forward and reverse transmission of the signal, verifying that the system has good transmission characteristics.

[0132] In the specification provided here, a large number of specific details are described. However, it can be understood that the embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures, and technologies are not shown in detail so as not to obscure the understanding of this specification.

[0133] In addition, those skilled in the art can understand that although some of the embodiments described herein include certain features contained in other embodiments rather than other features, the combination of the features of different embodiments also means being within the protection scope of the present invention and forms different embodiments. For example, in the above embodiments, those skilled in the art can use them in a combined manner according to the known technical solutions and the technical problems to be solved by this application.

Claims

1. A WPT system based on shielded capacitor plate data transmission, characterized in that: The system adds a signal transmission path using a shielded capacitor plate to a WPT system that uses a coupling coil to transfer energy; the WPT system includes two channels, an electric energy transmission channel and a signal transmission channel, wherein the signal transmission channel uses a four-resonance dual suppression structure to achieve dual full-duplex communication, and the four-resonance dual suppression structure includes four groups of parallel LC wave-blocking resonance networks and two groups of series LC compensation resonance networks; wherein the four groups of parallel LC wave-blocking resonance networks are respectively composed of a parallel network of a resonant inductor L1 and a resonant capacitor C1, a parallel network of a resonant inductor L2 and a resonant capacitor C2, a parallel network of a resonant inductor L3 and a resonant capacitor C3, and a parallel network of a resonant inductor L4 and a resonant capacitor C4, wherein the wave-blocking resonance network L1C1 and the wave-blocking resonance network L3C3 are at the same resonance frequency, and the wave-blocking resonance network L2C2 and the wave-blocking resonance network L4C4 are at the same resonance frequency; that is, the resonance point of the forward LC wave-blocking resonance network is exactly the suppression point of the reverse LC wave-blocking resonance network; the two groups of series LC compensation resonance networks are composed of the compensation inductor L PP and L SS and the equivalent mutual capacitance C S1 With C S2 Composition: Compensation inductance L PP and the equivalent mutual capacitance C S1 The series LC compensation resonant network of the primary side is formed in series. The parallel network of the resonant inductor L1 and the resonant capacitor C1 and the parallel network of the resonant inductor L2 and the resonant capacitor C2 are connected in parallel and then connected in series with the series LC compensation resonant network of the primary side, forming two sets of resonant networks on the primary side; the compensation inductor Lss and the equivalent mutual capacitance C S2 The series LC compensation resonant network of the secondary side is formed in series, and the parallel network of the resonant inductor L3 and the resonant capacitor C3 and the parallel network of the resonant inductor L4 and the resonant capacitor C4 are connected in parallel and then connected in series with the series LC compensation resonant network of the secondary side, forming two sets of resonant networks on the secondary side; The two groups of resonant networks on the primary side and the two groups of resonant networks on the secondary side are respectively used as equivalent SS compensation structures; The two data carriers are transmitted through an equivalent SS compensation structure formed by a parallel LC wave blocking resonance network and a series LC compensation resonance network. Through the equivalent SS compensation structure, two signal sources can be applied to the WPT system at the same time, thereby realizing dual full-duplex communication. The parallel LC wave blocking resonant network is used to block one carrier while transmitting another carrier. The carrier frequency is set as follows: Set the forward transmission carrier frequency to ω1, the reverse transmission carrier frequency to ω2, adjust the resonance point at the ω1 frequency to the suppression point at the ω2 frequency, and adjust the resonance point at the ω2 frequency to the suppression point at the ω1 frequency; The series LC compensation resonant network is used to compensate for the reactive power of the circuit and improve the transmission power of the shielding capacitor plate; the positive and negative signals are injected into the shielding capacitor plate through the LC wave-blocking resonant network and the resonant inductor, forming a high-frequency alternating potential difference on the shielding capacitor plate, generating a high-frequency electric field and exciting an alternating voltage on the shielding capacitor plate to form an interactive electric field; under the action of the interactive electric field, a displacement current is generated that "flows through" the shielding capacitor plate, transmitting the two data carriers to the shielding capacitor plate of the WPT system.

2. The WPT system based on shielded capacitor plate data transmission according to claim 1 is characterized in that: The power transmission channel is specifically: The input DC power supply Vin generates a sine wave with a frequency of ω0 through a full-bridge inverter circuit composed of four switch tubes. The power transmission part adopts an equivalent SS compensation structure. P and C S is the primary transmitting coil L P and the secondary receiving coil L S The compensation capacitor is used to eliminate the self-inductance of the coil. The secondary side of the power transmission is rectified by diodes D1~D4 to form a load R L powered by; The signal transmission channel is specifically: In order to perform full-duplex transmission of signals, two signal source analog signal inputs U1 and U2 are set on the primary side and secondary side of the signal transmission circuit respectively. The forward digital signal Date1 in and the reverse digital signal Date2in are modulated with a sine wave of a specified frequency through ASK modulation, and then injected into the signal transmission channel by a power amplifier. The primary transmitting coil Lp and the secondary receiving coil Ls are located on the inner side of the shielding capacitor plate. S1 is the equivalent mutual capacitance between the shielding capacitor plate transmitting ends P1 and P3, Cs2 is the equivalent mutual capacitance between the shielding capacitor plate receiving ends P2 and P4, C P12 With C P34 They are the equivalent self-capacitance between the transmitting end P1, P2 and the receiving end P3, P4 of the shielding capacitor plate; a π-type equivalent circuit is designed using four equivalent capacitors for subsequent circuit simplification and impedance analysis; In order to demodulate the forward and reverse signals, the sinusoidal carriers of the forward and reverse signals are located in different frequency bands. The carrier frequency of the forward signal is set to ω1, and the carrier frequency of the reverse signal is set to ω2. The forward signal is injected into the primary shielding capacitor plate through the wave-blocking resonant network L1C1 and the primary resonant inductor Lpp, and the secondary shielding capacitor plate then obtains a signal waveform at the sampling resistor R2 through the secondary resonant inductor Lss and the wave-blocking resonant network L3C3; after the signal waveform is sampled from R2, it is rectified by half-wave to become a signal waveform containing only the positive half axis, and the noise outside the passband is filtered out by the RC filter, and the waveform after filtering is amplified by the operational amplifier and sent to the envelope detector, and the detected envelope signal is compared with the given value to obtain a digital signal; The reverse signal is injected into the secondary shielding capacitor plate through the wave-blocking resonant network L4C4 and the secondary resonant inductor Lss, and then the signal is transmitted to the primary shielding capacitor plate through the displacement current, and then transmitted to the sampling resistor R1 through the primary resonant inductor Lpp and the wave-blocking resonant network L2C2 to obtain a signal waveform. After the signal waveform is sampled from R1, it is rectified by half-wave to form a signal waveform containing only the positive half axis. The noise outside the passband is filtered out by an RC filter, and the filtered waveform is amplified by an operational amplifier and sent to the envelope detector. The detected envelope signal is compared with a given value to obtain a digital signal.

3. The WPT system based on shielded capacitor plate data transmission according to claim 1 is characterized in that: The primary transmitting coil Lp and the secondary receiving coil Ls and their compensation capacitor C P With C S The following formula needs to be satisfied: Wherein, ω0 is the angular frequency of the sine wave generated by the full-bridge inverter circuit composed of four switch tubes through the input DC power supply Vin; f0 is the frequency corresponding to the angular frequency ω0; L P is the inductance of the primary transmitting coil, C P is the capacitance of the primary compensation capacitor; L S is the inductance of the secondary transmitting and receiving coil, C S is the capacitance of the secondary side compensation capacitor.

4. The WPT system based on shielded capacitor plate data transmission according to claim 2 is characterized in that: The topological structure of the shielding capacitor plate adopts a parallel disk coupling structure, specifically: The topological structure of the shielding capacitor plate transmitting end P1, P2 and receiving end P3, P4 adopts a parallel disk coupling structure. S1 is the equivalent mutual capacitance between P1 and P3, C S2 is the equivalent mutual capacitance between P2 and P4, C P12 With C P34 They are the equivalent self-capacitances of the parallel shielding capacitor plates at the transmitting ends P1 and P2 and the receiving ends P3 and P4 respectively.

5. The WPT system based on shielded capacitor plate data transmission according to claim 4 is characterized in that: The radius of the primary transmitting coil and the secondary receiving coil is R = 57mm, the outer radius of the inner shielding capacitor plate P2 is R1 = 40.5mm, the radius of the outer shielding capacitor plate P1 is R2 = 72.3mm, the difference between the inner diameter of the outer shielding capacitor plate P1 and the radius of the inner shielding capacitor plate P2 is lg = 1mm, and the parasitic capacitance difference between the coil and the shielding capacitor plate is almost zero, that is, the primary transmitting coil L P The parasitic capacitance between the outer shielding capacitor plate P3 and the inner shielding capacitor plate P4 of the secondary side is the same as that between the secondary side receiving coil L S The same as the parasitic capacitance between the outer shielding capacitor plate P1 and the inner shielding capacitor plate P2 of the primary side.

6. The WPT system based on shielded capacitor plate data transmission according to claim 5 is characterized in that: The selection process of the equivalent SS compensation structure is as follows: The full-duplex communication channel topology is equivalent to the CPT system circuit structure with equivalent SS compensation, and the input impedance is derived; When the system is in a resonant state and the input impedance Zin is purely resistive, set the constraints that the compensation inductors L1 and L2 need to meet; The frequencies of the forward signal carrier and the reverse signal carrier are set, the resonance point at the ω1 frequency is adjusted to the suppression point at the ω2 frequency, and the resonance point at the ω2 frequency is adjusted to the suppression point at the ω1 frequency, that is, the resonance point of the forward LC wave-blocking resonance network is exactly the suppression point of the reverse LC wave-blocking resonance network; The wave-blocking resonance network L1C1 and the wave-blocking resonance network L3C3 need to be connected in parallel resonance at the reverse carrier frequency ω2; The wave-blocking resonance network L2C2 and the wave-blocking resonance network L4C4 need to be connected in parallel resonance at the forward carrier frequency ω1; When transmitting forward signals, simplify the signal transmission network: The wave-blocking resonance network L1C1 and the compensation inductor L pp Equivalent to the equivalent inductance L eq1 ; The wave-blocking resonance network L3C3 and the compensation inductor L ss Equivalent to the equivalent inductance L eq2 ; When L eq1 Inductance and L eq2 When the inductance value satisfies the constraints of L1 and L2, the system is in resonance; The constraints for L1 and L2 are: Among them, C p12 and C p34 is the equivalent self-capacitance of the transmitting and receiving ends of the shielding capacitor plate, Cs is the equivalent mutual capacitance, and ω is the signal transmission carrier frequency; The reverse signal transmission is similar, simplifying the signal transmission network: The wave-blocking resonance network L2C2 and the compensation inductor L pp Equivalent to the equivalent inductance L eq3 , The wave-blocking resonance network L4C4 and the compensation inductor L ss Equivalent to the equivalent inductance L eq4 ; When L eq3 Inductance and L eq4 When the inductance value meets the constraints of L1 and L2, the system is in a resonant state. The resonant network L1, C1, L3, C3, L2, C2, L4, C4 and L are designed accordingly. pp With L ss The numerical value of .

7. A data parallel transmission method of a WPT system based on the shielded capacitor plate data transmission according to any one of claims 1 to 6, characterized in that: The method comprises: The carrier amplitude of the WPT system for shielded capacitor plate data transmission is changed according to different digital signals by using the Radial Shift Keying (ASK) method. The 01 digital signal sent by the host computer is converted into an analog signal with voltage through the DA conversion module, and then modulated with a sinusoidal carrier of the rated frequency by ASK modulation. When the analog signal is a high voltage, the ASK modulation output carrier amplitude is A1, representing the digital signal 1, and when the analog signal is a low voltage, the ASK modulation module outputs a carrier amplitude of A0, representing the digital signal 0, to achieve signal modulation; and then the signal carrier output of different amplitudes is achieved after passing through the same proportional amplification circuit; On the receiving side, the modulated carrier is obtained by half-wave rectification and then by an RC filter. The envelope wave of the carrier signal is obtained by using the incoherent envelope detection method to achieve demodulation of the carrier signal. Finally, the envelope wave is compared with a given voltage signal through a comparator. When the envelope wave is greater than the comparison voltage, the comparator outputs 1, and when it is less than the comparison voltage, the comparator outputs 0. At this point, the analog signal is converted into a digital signal.

8. The data parallel transmission method of the WPT system based on shielded capacitor plate data transmission according to claim 7 is characterized in that: The process of obtaining the carrier signal through envelope wave demodulation includes: The input carrier passes through a detection diode to obtain a positive half-cycle waveform, and through an RC parallel network, the charge and discharge constant τ is adjusted by changing the values ​​of the resistor R and the capacitor C to obtain a waveform carrier signal. The design of the RC parameters needs to meet two conditions: first, it should be ensured that the discharge speed of the capacitor C is slower than the drop speed of the single-cycle carrier voltage; second, the capacitor discharge time should be shorter than half of the time occupied by a digital signal in the carrier.

Images