An apparatus and method for simultaneous power and signal transmission for a radio system

Abstract

The application discloses a kind of electric energy and signal synchronous transmission device and method for wireless motor system, belong to wireless electric energy and signal synchronous transmission technical field.Forward transmission, the conduction angle of full-bridge inverter circuit changes according to sine function, signal wave is generated, and signal "1" is transmitted using energy carrier;The conduction angle of full-bridge inverter circuit is kept unchanged, and signal "0" is transmitted using energy carrier.Reverse transmission, change the conduction angle of active rectifier circuit according to the above method, reverse transmission information can be transmitted.Signal synchronous transmission rate can reach Kbps level.The application does not need to switch resistance or capacitance, does not need high-frequency signal generating circuit, wave suppression network, coupling transformer and other additional devices, so that the hardware cost of system can be effectively reduced.The application does not change the working frequency of system, always transmits electric energy at the resonant frequency of system, ensures the power and efficiency of electric energy transmission, and when transmitting information, the load voltage drop is small.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of wireless power and signal synchronous transmission, and more particularly relates to a device and method for wireless motor system power and signal synchronous transmission. BACKGROUND

[0002] In recent years, under the background of "carbon peak" and "carbon neutral", electric energy as a clean and efficient energy has been more widely used. Wireless power transmission technology realizes non-contact power transmission through electromagnetic coupling, overcoming the shortcomings of wired transmission mode such as line aging and lack of flexibility. Wireless motor system refers to a motor system integrated with wireless power transmission technology, which has the advantages of flexible structure and is applied to electric vehicles, mine drill bits, robot joints and other fields.

[0003] However, in some cases, not only power needs to be transmitted, but also bidirectional information transmission is needed to realize intelligent control, for example, in a wireless motor system, forward transmission of speed information to realize speed control of the motor; reverse transmission of voltage information to realize voltage stabilization control on the motor side. Therefore, it is meaningful to study wireless power and signal synchronous transmission technology for wireless motor system.

[0004] The separate channel type wireless power and signal synchronous transmission technology has two channels for transmitting energy and signal respectively, but this method has the disadvantages of large system size and high cost. The shared channel type wireless power and signal synchronous transmission technology uses one channel to transmit energy and signal, and the system structure is simple. The shared channel type wireless power and signal synchronous transmission technology can be divided into energy modulation type and carrier modulation type. The energy modulation type uses energy envelope wave to transmit signal, and the circuit structure is simple, but the signal transmission rate is slow, and the signal transmission will seriously affect the power quality. The carrier modulation type uses high-frequency carrier to transmit signal, and the transmission rate is very fast, and the signal transmission has little effect on power quality, but the circuit structure is complex and the cost is high. Therefore, a shared channel type wireless power and signal synchronous transmission technology with low cost, high transmission rate and little effect on power quality should be researched. SUMMARY

[0005] In view of the defects of the prior art, the purpose of the present application is to provide a device and method for wireless motor system power and signal synchronous transmission, which aims to optimize the circuit structure, reduce the cost, improve the signal transmission rate, and reduce the effect of signal transmission on power quality.

[0006] To achieve the above object, the application provides a kind of electric energy and signal synchronous transmission device for wireless motor system, wireless motor system is divided into transmitting side and receiving side according to the transmission direction of electric energy, transmitting side includes: DC power supply, full-bridge inverter circuit, transmitting module, receiving side includes receiving module, active rectifier circuit, three-phase inverter and motor;The input end of the full-bridge inverter circuit is connected with DC power supply, the output end of full-bridge inverter circuit is connected with the input end of transmitting module, and the full-bridge inverter circuit is used to convert the DC voltage of DC power supply into square wave voltage;The transmitting module and receiving module are SS type compensation topology, and are composed of coil series compensation capacitor, and the transmitting module and receiving module are electrically isolated, and electric energy is wirelessly transmitted by electromagnetic induction;The output end of the receiving module is connected with the input end of the active rectifier circuit;The active rectifier circuit is used to rectify the alternating voltage induced by the receiving coil into DC voltage;The output end of active rectifier circuit is connected with three-phase inverter and motor, and the active rectifier circuit is used to rectify the alternating voltage induced by the receiving coil into DC voltage, and the three-phase inverter circuit is used to control the motor.

[0007] The device includes a forward signal generator, a forward phase shift controller, a reverse signal detection module, a reverse signal generator, a reverse phase shift controller and a forward signal detection module. The forward signal generator and the forward phase shift controller are located at the transmitting side, and the reverse signal generator and the reverse phase shift controller are located at the receiving side. The forward signal generator is connected with the forward phase shift controller, and the reverse signal generator is connected with the reverse phase shift controller. The forward signal generator is used to convert a digital signal into an on-off angle of the full-bridge inverter circuit. The forward phase shift controller outputs four PWM signals to control the full-bridge inverter circuit. The reverse signal generator is used to convert a digital signal into an on-off angle of the active rectifier circuit. The reverse phase shift controller outputs four PWM signals to control the active rectifier circuit.

[0008] Preferably, the application does not need to change the working frequency of the system, and always works at the resonant frequency of the system. The device transmits electric energy and information, and ensures the power and efficiency of electric energy transmission. The following relationship is met:

[0009]

[0010] wherein, L is the inductance of the coil, C is the capacitance of the compensation capacitor, and the transmitting side and the receiving side use the same coil and compensation capacitor.

[0011] Preferably, the forward signal detection module extracts information sent by the transmitting side from the current of the receiving side coil. The forward signal detection module includes a LEM current sensor, a first-stage envelope detection circuit, a band-pass filter circuit, a second-stage envelope detection circuit and a comparator circuit.

[0012] wherein the LEM current sensor measures the receiving side coil current in a non-contact manner ; the first stage envelope detection circuit outputs the peak envelope wave of the receiving side coil current ; the band-pass filter circuit extracts the forward signal wave from the peak envelope wave of the receiving side coil current ; the second stage envelope detection circuit outputs the peak envelope wave of the forward signal wave ; the comparator circuit compares the peak envelope wave of the forward signal wave with the forward reference level If , the comparator circuit outputs 5V high level, indicating "1", and if , the comparator circuit outputs 0V low level, indicating "0", thereby demodulating the information sent by the transmitting side.

[0013] Preferably, the reverse signal detection module extracts the information sent by the receiving side from the transmitting side coil current. The reverse signal detection module comprises a LEM current sensor, a first stage envelope detection circuit, a band-pass filter circuit, a second stage envelope detection circuit, and a comparator circuit.

[0014] wherein the LEM current sensor measures the transmitting side coil current in a non-contact manner ; the first stage envelope detection circuit outputs the peak envelope wave of the transmitting side coil current ; the band-pass filter circuit extracts the reverse signal wave from the peak envelope wave of the transmitting side coil current ; the second stage envelope detection circuit outputs the peak envelope wave of the reverse signal wave ; the comparator circuit compares the peak envelope wave of the reverse signal wave with the reverse reference level If , the comparator circuit outputs 5V high level, indicating "1", and if , the comparator circuit outputs 0V low level, indicating "0", thereby demodulating the information sent by the receiving side.

[0015] Another aspect of the present application provides an electric energy and signal synchronous transmission method for a wireless motor system, which uses energy wave as carrier wave to transmit signal, converts the signal "1" to be sent into sinusoidal varying conduction angle, and converts the signal "0" to be sent into fixed conduction angle; when transmitting one bit signal "1", the duration of the sinusoidal varying conduction angle is , and when transmitting one bit signal "0", the duration of the fixed conduction angle is , This refers to the signal transmission rate. When transmitting signals in the forward direction, the conduction angle of the active rectifier circuit remains unchanged, while the conduction angle of the full-bridge inverter circuit is changed according to the rules described above. When transmitting information in the reverse direction, the conduction angle of the full-bridge inverter circuit remains unchanged, while the conduction angle of the active rectifier circuit is changed according to the rules described above. When transmitting signals in the forward direction, the information transmitted from the transmitting side is demodulated from the current in the receiving coil. When transmitting signals in the reverse direction, the information transmitted from the receiving side is demodulated from the current in the transmitting coil.

[0016] During forward information transmission, the forward signal generator converts the signal to be transmitted to the receiving side into the conduction angle of the full-bridge inverter circuit, and the forward phase-shift controller outputs a PWM with the corresponding phase according to the conduction angle. Simultaneously, the reverse signal generator outputs a fixed conduction angle, the reverse phase-shift controller outputs a PWM with a fixed phase, and no information is transmitted during the reverse direction.

[0017] When the transmitted signal is "1", the positive signal generator outputs... The conduction angle varies according to a sine wave pattern for each cycle. ,Right now:

[0018]

[0019] in, It is a positive fixed conduction angle. It is the positive signal modulation coefficient, which can control the change in the conduction angle, and thus control the amplitude of the signal wave; This refers to the frequency of the signal wave, which is lower than the system's switching frequency. In practical systems, It is discrete and cannot change continuously; therefore, a sine wave period is divided into... Segment, according to the system's resonant frequency It changes once in each resonance cycle. The value of . One cycle of the signal wave represents one bit of signal "1", therefore the resonant frequency of the system is... The frequency of the signal wave Signal transmission rate The relationship between them is:

[0020]

[0021] Forward phase shift controller according to conduction angle It outputs four PWM waves to control the full-bridge inverter circuit and sends a positive signal "1".

[0022] When the transmitted signal is "0", the positive signal generator outputs a positive fixed conduction angle. The duration is , which means that a bit signal "0" is sent in the forward direction. At this time, no signal wave is generated; during the forward transmission of the signal, the ripple of the load voltage can be controlled by . The smaller the , the smaller the .

[0023] When the reverse transmission signal is transmitted, the reverse signal generator converts the signal to be transmitted to the transmitting side into the conduction angle of the active rectifier circuit, and the reverse phase shift controller outputs the PWM of the corresponding phase according to the conduction angle. At the same time, the forward signal generator outputs a fixed conduction angle, and the forward phase shift controller outputs the PWM of the fixed phase, and the forward does not send information.

[0024] When the transmission signal "1" is transmitted, the reverse signal generator outputs a conduction angle that changes according to a sine wave rule in one period , that is:

[0025]

[0026] Among them, is the reverse fixed conduction angle, is the forward signal modulation coefficient, which can control the change amplitude of the conduction angle, and further control the amplitude of the signal wave; is the frequency of the signal wave, which is lower than the switching frequency of the system. In the actual system, is discrete and cannot change continuously; therefore, a sine wave period is divided into segments, and the value of is changed once every resonance period of the system . A signal wave of one period represents a bit signal "1", so the resonance frequency of the system , the frequency of the signal wave , and the transmission rate of the signal between them is:

[0027]

[0028] The reverse phase shift controller outputs four-way PWM waves according to the conduction angle , controls the full-bridge inverter circuit, and transmits a bit signal "1" in the reverse direction.

[0029] When the transmission signal "0" is transmitted, the forward signal generator outputs the reverse fixed conduction angle , with a duration of , which means that a bit signal "0" is sent in the forward direction. At this time, no signal wave is generated; during the forward transmission of the signal, the ripple of the load voltage can be controlled by . The smaller, The smaller.

[0030] Compared with the prior art, the above technical scheme of the present application can achieve the following beneficial effects:

[0031] (1) Compared with the prior art of carrier injection type wireless power and signal synchronous transmission technology, the present application does not realize information transmission function by switching load or compensating capacitor, does not need high-frequency carrier signal generating circuit, does not need wave suppression network composed of passive devices, and does not need coupling transformer, so that the circuit structure can be simplified, and the system complexity and hardware cost can be effectively reduced.

[0032] (2) Compared with the prior art of energy modulation type wireless power and signal synchronous transmission technology, the present application can improve the signal transmission rate to the level of Kbps. The present application does not need to switch resistance or capacitance, simplifies the control scheme, and reduces the hardware cost.

[0033] (3) Compared with the prior art of energy modulation type wireless power and signal synchronous transmission technology, the present application does not need to change the frequency of power transmission, always transmits power at the resonant frequency, and can ensure the efficiency of power transmission. Moreover, the present application has small load voltage drop during signal transmission. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 A schematic diagram of an electric energy and signal synchronous transmission device for a wireless motor system is provided for the embodiment of the present application;

[0035] Figure 2 A main circuit diagram of a wireless motor system is provided for the embodiment of the present application;

[0036] Figure 3 Detailed contents of a detection module are provided for the embodiment of the present application;

[0037] Figure 4 A flowchart of a signal transmission method is provided for the embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0039] As Figure 1As shown, the present application provides a kind of power and signal synchronous transmission device for wireless motor system, comprising: DC power supply, positive signal generator, positive phase shift controller, full-bridge inverter circuit, reverse signal detection module, transmitting module, receiving side includes receiving module, reverse signal generator, reverse phase shift controller, active rectifier circuit, positive signal detection module, three-phase inverter and motor.Full-bridge inverter circuit input is connected with DC power supply, the output of full-bridge inverter circuit is connected with the input of transmitting module, and full-bridge inverter circuit is used to convert the direct current voltage of DC power supply into square wave voltage;Transmitting module and receiving module are SS type compensation topology, and are composed of coil series compensation capacitor, transmitting module and receiving module are electrically isolated, and power is wirelessly transmitted by electromagnetic induction;The output of receiving module is connected with the input of active rectifier circuit;Active rectifier circuit is used to rectify the alternating voltage induced by receiving coil into direct current voltage;The output of active rectifier circuit is connected with three-phase inverter and motor, and active rectifier circuit is used to rectify the alternating voltage induced by receiving coil into direct current voltage, and three-phase inverter circuit is used to control motor.

[0040] Positive signal generator and positive phase shift controller are located in transmitting side, and reverse signal generator and reverse phase shift controller are located in receiving side.Positive signal generator is connected with positive phase shift controller, and reverse signal generator is connected with reverse phase shift controller;Positive signal generator is used to convert digital signal into the conduction angle of full-bridge inverter circuit;Positive phase shift controller outputs four-way PWM, controls full-bridge inverter circuit;Reverse signal generator is used to convert digital signal into the conduction angle of active rectifier circuit;Reverse phase shift controller outputs four-way PWM, controls active rectifier circuit.

[0041] As shown in Figure 2 Full-bridge inverter circuit is composed of four MOSFET, and the input of full-bridge inverter circuit is connected with DC power supply, and the output is connected with transmitting module.Full-bridge inverter circuit is used to convert the direct current voltage of DC power supply into high-frequency square wave voltage according to certain phase shift angle and generate corresponding signal wave, and its operating characteristics are adjusted by positive phase shift angle controller.

[0042] Specifically, transmitting module and receiving module belong to SS type compensation topology, and are composed of coupling coil series compensation capacitor, and power and information are wirelessly transmitted by electromagnetic induction.

[0043] Specifically, active rectifier circuit is composed of four MOSFET and a capacitor.Four MOSFETs form active rectifier bridge, and the AC side is connected with receiving coil, and the DC side is connected with capacitor.Active rectifier circuit is used to rectify the alternating voltage induced by receiving coil into direct current voltage and generate corresponding signal wave, and its operating characteristics are adjusted by reverse phase shift angle controller.

[0044] Specifically, the forward signal detection module extracts the information transmitted from the transmitting side from the current in the receiving coil. For example... Figure 3 As shown, the forward signal detection module includes an LEM current sensor, a first-stage envelope detection circuit, a bandpass filter circuit, a second-stage envelope detection circuit, and a comparator circuit.

[0045] Specifically, the reverse signal detection module extracts the information transmitted from the receiving side from the current in the transmitting coil. For example... Figure 3 As shown, the reverse signal detection module includes an LEM current sensor, a first-stage envelope detection circuit, a bandpass filter circuit, a second-stage envelope detection circuit, and a comparator circuit.

[0046] Based on the above-described apparatus, the present invention proposes a method for synchronous transmission of electrical energy and signals in a wireless motor system as follows: Figure 4 A flowchart of the signal transmission method:

[0047] There are two processes when transmitting a signal in the forward direction: transmitting the signal in the forward direction and demodulating the signal in the forward direction.

[0048] When transmitting a signal in the forward direction, the forward signal generator converts the signal to be transmitted to the receiving side into the conduction angle of the full-bridge inverter circuit, and the forward phase-shift controller outputs a PWM with the corresponding phase according to the conduction angle. At the same time, the reverse signal generator outputs a fixed conduction angle, the reverse phase-shift controller outputs a PWM with a fixed phase, and no information is transmitted in the reverse direction.

[0049] When the transmitted signal is "1", the positive signal generator outputs... The conduction angle varies according to a sine wave pattern for each cycle. ,Right now:

[0050]

[0051] in, It is a positive fixed conduction angle. It is the positive signal modulation coefficient, which can control the change in the conduction angle, and thus control the amplitude of the signal wave; This refers to the frequency of the signal wave, which is lower than the system's switching frequency. In practical systems, It is discrete and cannot change continuously; therefore, a sine wave period is divided into... Segment, according to the system's resonant frequency It changes once in each resonance cycle. The value of . One cycle of the signal wave represents one bit of signal "1", therefore the resonant frequency of the system is... The frequency of the signal wave Signal transmission rate The relationship between them is:

[0052]

[0053] Forward phase-shifted controller according to firing angle Output four-way PWM wave, control full-bridge inverter circuit, forward sends a bit signal "1".

[0054] When transmitting signal "0", the forward signal generator outputs a fixed forward conduction angle , the duration is , indicating that the forward sends a bit signal "0". At this time, no signal wave is generated.

[0055] During the forward transmission signal, the ripple of the load voltage can be controlled by . The smaller, The smaller.

[0056] When demodulating forward information, the forward signal detection module is used. Among them, the LEM current sensor measures the receiving side coil current in a non-contact manner; the first-stage envelope detection circuit outputs the peak envelope wave of the receiving side coil current ; the band-pass filter circuit extracts the forward signal wave from the peak envelope wave of the receiving side coil current ; the second-stage envelope detection circuit outputs the peak envelope wave of the forward signal wave ; the comparator circuit compares the peak envelope wave of the forward signal wave and the forward reference level : if , the comparator circuit outputs a 5V high level, indicating "1", if , the comparator circuit outputs a 0V low level, indicating "0", so as to demodulate the information sent by the transmitting side.

[0057] When transmitting a reverse signal, there are two processes: reverse signal transmission and reverse signal demodulation.

[0058] When transmitting a reverse signal, the reverse signal generator converts the signal to be transmitted to the transmitting side into the conduction angle of the active rectifier circuit, and the reverse phase-shifted controller outputs the PWM of the corresponding phase according to the conduction angle. At the same time, the forward signal generator outputs a fixed conduction angle, and the forward phase-shifted controller outputs a fixed phase PWM, and the forward does not send information.

[0059] When transmitting signal "1", the reverse signal generator outputs a conduction angle that changes according to a sine wave rule , i.e.

[0060]

[0061] wherein, is the reverse fixed conduction angle, is the forward signal modulation coefficient, which can control the variation range of the conduction angle, and further control the amplitude of the signal wave; is the frequency of the signal wave, which is lower than the switching frequency of the system. In the actual system, is discrete and cannot be continuously changed; therefore, one period of a sine wave is divided into segments, and the value of is changed once every resonance period of the system . One period of the signal wave represents a bit of signal “1”, and therefore the resonance frequency of the system , the frequency of the signal wave , and the transmission rate of the signal are related as follows:

[0062]

[0063] The reverse phase-shift controller outputs four-way PWM waves according to the conduction angle , which controls the full-bridge inverter circuit and reversely transmits a bit of signal “1”.

[0064] When transmitting a signal “0”, the forward signal generator outputs a reverse fixed conduction angle , with a duration of , indicating that a bit of signal “0” is transmitted forward. At this time, no signal wave is generated; during the transmission of the forward signal, the ripple of the load voltage can be controlled by . The smaller is, the smaller is.

[0065] When demodulating the reverse information, the reverse signal detection module is used. The LEM current sensor measures the transmitting-side coil current in a non-contact manner; the first-stage envelope detection circuit outputs the peak envelope wave of the transmitting-side coil current ; the band-pass filter circuit extracts the reverse signal wave from the peak envelope wave of the transmitting-side coil current; the second-stage envelope detection circuit outputs the peak envelope wave of the reverse signal wave ; the comparator circuit compares the peak envelope wave of the reverse signal wave with the reverse reference level : if , the comparator circuit outputs a 5V high level, indicating “1”, and if , the comparator circuit outputs a 0V low level, indicating “0”, thereby demodulating the information transmitted by the receiving side.

[0066] Those skilled in the art will readily understand that the above described are only the preferred embodiments of the present application and are not intended to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A synchronization transmission method for a power and signal synchronization transmission device for a wireless motor system, the power and signal synchronization transmission device comprising a forward signal generator, a forward phase shift controller, a reverse signal detection module, a reverse signal generator, a reverse phase shift controller, and a forward signal detection module; the forward signal generator and the forward phase shift controller are connected, and the reverse signal generator and the reverse phase shift controller are connected; the forward signal detection module is used to extract the information transmitted from the transmitting side from the receiving side coil current; The reverse signal detection module is used to extract the information transmitted from the receiving side from the transmitting coil current; the forward signal generator is used to convert the signal to be transmitted into the conduction angle of the full-bridge inverter circuit; the reverse signal generator is used to convert the signal to be transmitted into the conduction angle of the active rectifier circuit; the forward phase shift controller is used to control the full-bridge inverter circuit, and the reverse phase shift controller is used to control the active rectifier circuit; characterized in that... include: (1) Convert the signal "1" to be transmitted into a sinusoidal variable conduction angle, and convert the signal "0" to be transmitted into a fixed conduction angle; when transmitting a bit of signal "1", the duration of the sinusoidal variable conduction angle is: When sending a single bit signal "0", the duration of the fixed conduction angle is... , It refers to the signal transmission rate; (2) When transmitting signals in the forward direction, the conduction angle of the active rectifier circuit remains unchanged, and the conduction angle of the full-bridge inverter circuit is changed according to the rule in (1); when transmitting information in the reverse direction, the conduction angle of the full-bridge inverter circuit remains unchanged, and the conduction angle of the active rectifier circuit is changed according to the rule in (1). (3) When transmitting a signal in the forward direction, the information sent by the transmitting side is demodulated from the current of the receiving coil; when transmitting a signal in the reverse direction, the information sent by the receiving side is demodulated from the current of the transmitting coil.

2. The method as described in claim 1, characterized in that, When transmitting signals in the forward direction, it includes both the forward transmission signal and the forward demodulation signal; When transmitting a signal in the forward direction, the forward signal generator converts the signal to be transmitted to the receiving side into the conduction angle of the full-bridge inverter circuit. The forward phase shift controller outputs the corresponding phase of PWM according to the conduction angle. At the same time, the reverse signal generator outputs a fixed conduction angle, and the reverse phase shift controller outputs a fixed phase of PWM. No signal is transmitted in the reverse direction. During forward demodulation, the forward signal wave is extracted from the peak envelope of the receiving coil current. The peak envelope of the output positive signal wave Peak envelope of a positive signal wave and positive reference level Comparison: If The comparator circuit outputs a 5V high level, indicating a demodulated signal "1". The comparator circuit outputs a low level of 0V, indicating that the demodulated signal is "0".

3. The method as described in claim 2, characterized in that, When transmitting a signal in the forward direction, if the transmitted signal is "0", the forward signal generator outputs a fixed forward conduction angle. When the transmitted signal is "1", the positive signal generator outputs a positive sinusoidal change in the conduction angle. The positive sinusoidal changing conduction angle is equal to the positive fixed conduction angle superimposed with the fluctuation component, that is: in, These are the forward signal modulation coefficients. It is the frequency of the signal wave. It is the resonant frequency of the system. t It's time.

4. The method as described in claim 3, characterized in that, During the forward signal transmission, the load voltage ripple Depend on control, The smaller, The smaller.

5. The method as described in claim 1, characterized in that, Reverse signal transmission includes both reverse information transmission and reverse demodulation of signals; When transmitting a signal in reverse, the inverting signal generator converts the signal that needs to be transmitted to the transmitting side into the conduction angle of the active rectifier circuit. The reverse phase-shift controller outputs a PWM of the corresponding phase according to the conduction angle; at the same time, the forward signal generator outputs a fixed conduction angle, the forward phase-shift controller outputs a PWM of a fixed phase, and no information is sent in the forward direction; During reverse demodulation, the reverse signal wave is extracted from the peak envelope of the transmitting coil current. The peak envelope of the output reverse signal wave ; Peak envelope of the reverse signal wave and reverse reference level Comparison: If The comparator circuit outputs a 5V high level, indicating that a "1" has been demodulated. The comparator circuit outputs a low level of 0V, indicating that the demodulated signal is "0".

6. The method as described in claim 5, characterized in that, When transmitting a signal in reverse, if the transmitted signal is "0", the reverse signal generator outputs a fixed reverse conduction angle. When the transmitted signal is "1", the inverting signal generator outputs a reverse sinusoidal change in the conduction angle. The reverse sinusoidal conduction angle is equal to the reverse fixed conduction angle superimposed with the fluctuation component, that is: in, It is the inverse signal modulation coefficient. It is the frequency of the signal wave. It is the resonant frequency of the system. t It's time.

7. The method as described in claim 6, characterized in that, During reverse signal transmission, the load voltage ripple Depend on control, The smaller, The smaller.

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