Demodulation device, demodulation method, and wireless power transmission system

Abstract

The invention provides a demodulation device, a demodulation method and a wireless power transmission system, and the device comprises a signal conversion unit which comprises a first differential input end and a second differential input end which are respectively used for being coupled to the two ends of a first resonant capacitor, and an output end which outputs a sine wave signal with DC offset, wherein the first resonant capacitor is used for forming a resonant cavity with the first coil; the signal extraction unit comprises an input end coupled to the output end of the signal conversion unit so as to receive the sine wave signal with the direct current offset, and the signal extraction unit is used for extracting peak information and phase information of the sine wave signal with the direct current offset; a high-frequency intermediate signal is output at the output end of the signal extraction unit; and the signal processing unit is provided with an input end coupled to the output end of the signal extraction unit, and is used for outputting a low-frequency square wave signal at the output end of the signal processing unit according to the high-frequency intermediate signal.

Description

Technical Field

[0001] The present application relates to a wireless power transmission system, and more particularly to a demodulation device, a demodulation method and a wireless power transmission system. Background Art

[0002] With further development of technology, wireless power transmission has become an efficient and convenient mechanism for powering or charging battery-based mobile devices (such as mobile phones, tablets, digital cameras, MP3 players and / or similar devices). A wireless power transmission system usually includes a primary side transmitter and a secondary side receiver.

[0003] See also Figure 1 The schematic diagram of a typical wireless power transmission system block diagram is shown. The wireless power transmission system includes a transmitter 10 and a receiver 20. The transmitter 10 includes a transmitter circuit 11 and a primary resonant cavity connected in cascade, wherein the primary resonant cavity includes a first coil Lp and a first resonant capacitor Cp connected in series. The receiver 20 includes a secondary resonant cavity and a receiver circuit 21 connected in cascade, wherein the secondary resonant cavity includes a second coil Ls (or receiver coil Ls) and a second resonant capacitor Cs connected in series.

[0004] In practical applications, the transmitter 10 can be configured in a charging pad, wherein the first coil Lp is placed under the top surface of the charging pad. The receiver 20 can be embedded in a mobile device (such as a mobile phone, a tablet computer, a digital camera, an MP3 player and / or similar devices).

[0005] When the receiver 20 is placed within the output power range of the transmitter 10, such as when the mobile device is placed near a charging pad, magnetic coupling is established between the first coil Lp and the second coil Ls, such as a coupling coefficient of k, and the output power of the transmitter 10 is transmitted to the receiver 20, that is, wireless power transmission is formed between the transmitter 10 and the receiver 20 to charge the load (such as a rechargeable battery and / or battery pack in a mobile device).

[0006] Please refer to Figure 1 The transmitter 10 further includes a demodulation device 12, and the receiver 20 further includes a modulation device 22. The demodulation device 12 and the modulation device 22 constitute a communication device to perform wireless communication between the receiver 20 and the transmitter 10.

[0007] Specifically, the transmitter circuit 11 can operate according to the control signal generated by the operating parameters transmitted from the receiver 20. In practical applications, the signal is usually transmitted between the transmitter 10 and the receiver 20 in the form of a modulated signal. Among them, amplitude shift keying (ASK) is a modulation scheme widely used in wireless power transmission systems. ASK is performed by modulating the amplitude of an analog signal in a wireless power transmission system, wherein the modulation device 22 is used as an ASK modulator and the demodulation device 12 is used as an ASK demodulator. The ASK demodulator detects the signal of the ASK modulator and obtains the communication signal by demodulating the state change of the ASK modulator. The transmitter circuit 11 generates a control signal for controlling the operation of the transmitter circuit 11 according to the communication signal.

[0008] With the further development of wireless power transmission systems, the frequency of wireless power transmission systems has also greatly increased. The operating frequency of the wireless charging WPC1.3 standard is in the range of 87KHz to 205KHz. The ASK signal modulation method of the receiver 20 is mainly capacitive modulation. The advantage of ASK signal modulation is that the modulated signal is very strong and easy to demodulate. The disadvantage of ASK signal modulation is that the modulation may reduce the efficiency of wireless power transmission. In addition, this modulation method may cause noise problems.

[0009] To solve the above problems, the operating frequency of some receivers has been increased to 360KHz. The modulation method has been changed from a capacitance-based modulation scheme to a resistance-based modulation scheme. The data signal generated by this modulation method is relatively weak. Traditional demodulation methods may have a high packet loss rate when processing weak data signals, or even fail to successfully decrypt the packet.

[0010] Therefore, the industry is in urgent need of a demodulation device or a demodulation method for effectively and reliably demodulating communication information transmitted from a receiver to a transmitter. Summary of the invention

[0011] According to one embodiment, a demodulation device applied to a wireless power transmission system is provided, comprising: a signal conversion unit, comprising a first differential input terminal and a second differential input terminal respectively used to couple to two ends of a first resonant capacitor, and an output terminal outputting a sinusoidal wave signal with a DC offset, wherein the first resonant capacitor is used to form a resonant cavity with a first coil; a signal extraction unit, comprising an input terminal coupled to the output terminal of the signal conversion unit to receive the sinusoidal wave signal with a DC offset, the signal extraction unit being used to extract peak information and phase information of the sinusoidal wave signal with a DC offset to output a high-frequency intermediate signal at the output terminal of the signal extraction unit; a signal processing unit, having an input terminal coupled to the output terminal of the signal extraction unit, and being used to output a low-frequency square wave signal at the output terminal of the signal processing unit according to the high-frequency intermediate signal.

[0012] Furthermore, the resonant cavity is a resonant cavity in a transmitter of a wireless power transmission system, wherein the first coil is used for magnetic coupling with the second coil.

[0013] Furthermore, the signal conversion unit includes a differential amplifier, and the first differential input terminal and the second differential input terminal of the signal conversion unit are respectively a non-inverting input terminal and an inverting input terminal of the differential amplifier.

[0014] Furthermore, the signal extraction unit includes a diode switch series branch formed by a diode and a switch tube connected in series, and the diode switch series branch is connected between the input end and the output end of the signal extraction unit, wherein the anode of the diode is used to connect the input end of the signal extraction unit, and the cathode of the diode is used to connect the output end of the signal extraction unit.

[0015] Furthermore, the control end of the switch tube receives a switch control signal, the frequency of the switch control signal is the same as the frequency of the sine wave signal, and the duty cycle of the switch control signal is about 50%.

[0016] Furthermore, the control end of the switch tube receives a switch control signal, and the switch control signal is a voltage signal of the second end of the first resonant capacitor, wherein the second end of the first resonant capacitor is used to connect to the second common node of a switch unit, and the first end of the first resonant capacitor is used to connect to the first end of the first coil, or the switch control signal is a voltage signal of the second end of the first coil, wherein the second end of the first coil is used to connect to the first common node of a switch unit, wherein the first common node and the second common node are both common nodes of two switch tubes in the switch unit.

[0017] Furthermore, the signal processing unit includes a resistor-capacitor parallel branch connected between the output terminal of the signal extraction unit and a ground terminal.

[0018] Furthermore, the signal processing unit includes: a bandpass filter unit, used to convert the high-frequency intermediate signal into a first low-frequency intermediate signal, wherein the bandpass filter unit includes a resistor-capacitor parallel branch connected between the output end of the signal extraction unit and the ground end; a low-frequency signal amplifier unit, used to amplify the first low-frequency intermediate signal to form a second low-frequency intermediate signal; and a comparator unit, used to form the low-frequency square wave signal according to the second low-frequency intermediate signal.

[0019] According to another embodiment, a demodulation method for a wireless power transmission system is provided, comprising: using a signal conversion unit to convert a voltage signal on a first resonant capacitor into a sinusoidal wave signal with a DC offset, wherein the first resonant capacitor is used to form a resonant cavity with a first coil; using a signal extraction unit to extract peak information and phase information of the sinusoidal wave signal with a DC offset to form a high-frequency intermediate signal; and using a signal processing unit to convert the high-frequency intermediate signal into a low-frequency square wave signal.

[0020] Furthermore, a diode switch series branch formed by a diode and a switch tube connected in series is provided in the signal extraction unit, and the diode switch series branch is connected between the input end and the output end of the signal extraction unit; a switch control signal with a frequency the same as the frequency of the sinusoidal wave signal and a duty cycle of approximately 50% is provided to control the on and off of the switch tube, and during the period when the switch tube is turned on and the voltage at the anode end of the diode is greater than the voltage at the cathode end of the diode, the sinusoidal wave signal is transmitted to the output end of the signal extraction unit, and during the period when the switch tube is turned off or the voltage at the anode end of the diode is less than the voltage at the cathode end of the diode, the sinusoidal wave signal is blocked to form the high-frequency intermediate signal.

[0021] Furthermore, a resistor-capacitor parallel branch connected between the output terminal of the signal extraction unit and the ground terminal is provided in the signal processing unit to provide a voltage applied to the cathode terminal of the diode at the output terminal of the signal extraction unit.

[0022] Furthermore, the switch control signal comes from a common node of two switch tubes in a transmitter circuit of the wireless power transmission system.

[0023] According to another embodiment, a wireless power transmission system is provided, comprising: a transmitter coil configured to be magnetically coupled with a receiver coil; a first resonant capacitor connected in series with the transmitter coil and a transmitter circuit of the wireless power transmission system; and a demodulation device, comprising: a signal conversion unit comprising a first differential input terminal and a second differential input terminal respectively used to couple to two ends of the first resonant capacitor, and an output terminal outputting a sinusoidal wave signal with a DC offset; a signal extraction unit comprising an input terminal coupled to the output terminal of the signal conversion unit, the input terminal being used to receive the sinusoidal wave signal with a DC offset, the signal extraction unit being used to extract peak information and phase information of the sinusoidal wave signal with a DC offset to output a high-frequency intermediate signal at the output terminal of the signal extraction unit; and a signal processing unit having an input terminal coupled to the output terminal of the signal extraction unit, and being used to output a low-frequency square wave signal at the output terminal of the signal processing unit according to the high-frequency intermediate signal.

[0024] Furthermore, the signal extraction unit includes a diode switch series branch formed by a diode and a switch tube connected in series, and the diode switch series branch is connected between the input end and the output end of the signal extraction unit, wherein the anode of the diode is used to connect the input end of the signal extraction unit, and the cathode of the diode is used to connect the output end of the signal extraction unit; the signal processing unit includes a resistor and capacitor parallel branch connected between the output end of the signal extraction unit and the ground end, wherein the control end of the switch tube receives a switch control signal, the frequency of the switch control signal is the same as the frequency of the sinusoidal wave signal, and the duty cycle of the switch control signal is approximately 50%.

[0025] The features and technical advantages of the present disclosure have been summarized quite extensively above so that the detailed description disclosed below may be better understood. Additional features and advantages of the present disclosure will be described below, which constitute the subject matter of the claims of the present disclosure. It will be appreciated by those skilled in the art that the disclosed concepts and specific embodiments may be easily used as a basis for modifying or designing other structures or processes for achieving the same purpose of the present disclosure. It will also be appreciated by those skilled in the art that such equivalent structures do not depart from the spirit and scope of the present disclosure as set forth in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description in conjunction with the accompanying drawings, in which:

[0027] Figure 1 A schematic diagram of a typical wireless power transmission system block diagram is shown;

[0028] Figure 2 A schematic diagram of a main circuit of a wireless power transmission system according to an embodiment of the present application is shown;

[0029] Figure 3 The present invention shows an embodiment of the present invention. Figure 1 Schematic diagram of a demodulation device of a wireless power transmission system;

[0030] Figure 4 A schematic diagram showing working waveforms of a demodulation device for a wireless power transmission system according to an embodiment of the present application is shown;

[0031] Figure 5 Another embodiment of the present application is shown. Figure 1 Schematic diagram of a demodulation device of a wireless power transmission system;

[0032] Figure 6 The present invention shows an embodiment of the present invention. Figure 3 and Figure 5 A circuit diagram of a signal processing unit in FIG.

[0033] Figure 7 A flow chart of a demodulation method for a wireless power transmission system according to an embodiment of the present application is shown.

[0034] Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated.The figures are drawn to clearly illustrate the relevant aspects of the various embodiments and are not necessarily drawn to scale. DETAILED DESCRIPTION

[0035] The making and use of the currently preferred embodiments are discussed in detail below. However, it should be understood that the present disclosure provides many applicable inventive concepts that can be embodied in various specific contexts. The specific embodiments discussed are only used to illustrate the specific ways to make and use the present invention and do not limit the scope of the present invention.

[0036] In one embodiment of the present application, a method is provided that can be applied to Figure 1 A demodulation device for a wireless power transmission system. Figure 1 The demodulation device 12 and the modulation device 22 constitute a communication device, which is configured to provide in-band communication between the receiver 20 and the transmitter 10 of the wireless power transmission system.

[0037] Specifically, in one embodiment, the demodulation device 12 and the modulation device 22 are designed based on the amplitude shift keying (ASK) modulation used in the wireless power transmission system. The modulation device 22 in the receiver 20 is used as an ASK modulator, and the demodulation device 12 in the transmitter 10 is used as an ASK demodulator. The ASK demodulator detects the high level state and the low level state of the ASK modulation, and obtains the communication information by demodulating the state change of the ASK modulation.

[0038] Of course, the present application is not limited to the use of amplitude shift keying (ASK) modulation, and other modulation methods, such as frequency shift keying modulation, may also be used.

[0039] In actual implementation, the transmitter circuit 11 can be implemented as an inverter circuit, and the receiver circuit 21 can be implemented as a rectifier circuit. Figure 2 The main circuit diagram of the wireless power transmission system is shown in FIG. Figure 2 As shown, the transmitter circuit 11 is implemented as a full-bridge inverter switch unit, and the receiver circuit 21 is implemented as a full-bridge rectifier switch unit.

[0040] Specifically, Figure 2As shown, the full-bridge inverter switch unit includes a first switch tube Q1, a second switch tube Q2, a third switch tube Q3 and a fourth switch tube Q4. The first switch tube Q1 and the second switch tube Q2 are connected in series to form a first switch bridge arm, and the third switch tube Q3 and the fourth switch tube Q4 are connected in series to form a second switch bridge arm. The first switch bridge arm is connected in parallel with the second switch bridge arm to receive electrical energy suitable for processing by the transmitter circuit 11.

[0041] The common node of the first switch tube Q1 and the second switch tube Q2 is represented as the first common node SW1, and the common node of the third switch tube Q3 and the fourth switch tube Q4 is represented as the second common node SW2. The first coil Lp and the first resonant capacitor Cp are connected in series between the first common node SW1 and the second common node SW2.

[0042] In actual implementation, by controlling the on and off of the first switch tube Q1 , the second switch tube Q2 , the third switch tube Q3 and the fourth switch tube Q4 , a square wave signal is output at the first common node SW1 and the second common node SW2 .

[0043] Please refer to Figure 2 The full-bridge rectifier switch unit includes a fifth switch tube Q5, a sixth switch tube Q6, a seventh switch tube Q7 and an eighth switch tube Q8. The fifth switch tube Q5 and the sixth switch tube Q6 are connected in series to form a fourth switch bridge arm, the seventh switch tube Q7 and the eighth switch tube Q8 are connected in series to form a fifth switch bridge arm, and the fourth switch bridge arm is connected in parallel with the fifth switch bridge arm to output an electrical signal. The second coil Ls and the second resonant capacitor Cs are connected in series between the common node of the fifth switch tube Q5 and the sixth switch tube Q6 and the common node of the seventh switch tube Q7 and the eighth switch tube Q8.

[0044] The transmitter circuit 11 may also be implemented as other inverter switch units, such as a half-bridge inverter switch unit, a push-pull inverter switch unit, any combination thereof and / or similar switch units. The present application does not limit its specific structure as long as it can invert DC power into AC power.

[0045] The receiver circuit 21 may also be implemented as a full-wave diode bridge or a half-wave diode bridge. The present application does not limit its specific structure as long as it can rectify AC power into DC power.

[0046] Likewise, the present application does not limit the specific type of the above-mentioned switch tube, as long as it can be controlled to be turned on or off.

[0047] See also Figure 3 The present application of an embodiment shown in Figure 1 Schematic diagram of a demodulation device of a wireless power transmission system in FIG. The demodulation device 12 includes:

[0048] The signal conversion unit 100 comprises a first differential input terminal and a second differential input terminal respectively coupled to two ends of a first resonant capacitor Cp, and an output terminal outputting a sinusoidal wave signal Vsin with a DC offset, wherein the first resonant capacitor Cp is used to form a resonant cavity with a first coil Lp;

[0049] The signal extraction unit 200 includes an input terminal coupled to the output terminal of the signal conversion unit 100 to receive the sinusoidal wave signal Vsin with a DC offset, and the signal extraction unit 200 is used to extract peak information and phase information of the sinusoidal wave signal Vsin with a DC offset to output a high-frequency intermediate signal Vmid at the output terminal of the signal extraction unit 200;

[0050] The signal processing unit 300 has an input terminal coupled to the output terminal of the signal extraction unit 200 and is used to output a low-frequency square wave signal Vm at an output terminal of the signal processing unit 300 according to the high-frequency intermediate signal Vmid.

[0051] The low-frequency square wave signal Vm is a signal suitable for processing by a microprocessor (MCU). Figure 1 , the resonant cavity is a resonant cavity in the transmitter 10 of the wireless power transmission system, wherein the first coil Lp is used for magnetic coupling with the second coil Ls. Figure 1 In the embodiment, the second coil Ls and the second resonant capacitor Cs also form a resonant cavity.

[0052] In a specific embodiment, if Figure 3 As shown, the signal conversion unit 100 includes a differential amplifier 110, and the first differential input terminal and the second differential input terminal of the signal conversion unit 100 are respectively the non-inverting input terminal and the inverting input terminal of the differential amplifier 110. Figure 3 The in-phase input terminal is connected to the common node of the first coil Lp and the first resonant capacitor Cp through the resistor R2, and the inverting input terminal is connected to the other end of the first resonant capacitor Cp through the resistor R1. Figure 2 In the specific circuit shown, the inverting input terminal is connected to the second common node SW2 via the resistor R1, and the non-inverting input terminal is connected to the first common node SW1 via the resistor R2 and the first coil Lp.

[0053] Furthermore, Figure 3 As shown, a resistor-capacitor parallel branch formed by a resistor R4 and a capacitor C2 in parallel is also connected between the non-inverting input terminal of the differential amplifier 110 and the bias voltage Vfb, and a resistor-capacitor parallel branch formed by a resistor R3 and a capacitor C1 in parallel is also connected between the non-inverting input terminal and the output terminal of the differential amplifier 110. In some embodiments, the bias voltage Vfb is 1.8V, but the present application does not limit its specific value.

[0054] Of course, the present application does not limit the signal conversion unit 100 to Figure 3 The specific structure shown in the figure is not limited to the values ​​of the internal resistance and capacitance. As long as it can convert the differential input signal on the first resonant capacitor Cp into a sine wave signal Vsin with a DC offset, it can be used. Those skilled in the art will know that there may be many variations, alternatives and modifications according to different applications and design requirements.

[0055] In actual operation, the differential input signal received by the differential amplifier 110 on the first resonant capacitor Cp includes a sine wave component and a square wave component. The differential amplifier 110 can remove the square wave component in the input signal and generate a sine wave signal Vsin with a DC offset. Figure 4 The sine wave signal Vsin with DC offset in Figure 4 The working waveform diagram of the demodulation device for the wireless power transmission system is shown. (a) shows the working waveform of the wireless power transmission system when it is working in the original state, that is, the demodulation process when the modulation process is not applicable to the wireless power transmission system or the modulation process is in the logic "0" state. (b) shows the working waveform of the wireless power transmission system when it is working in the modulation state, that is, the demodulation process when the modulation process is applicable to the wireless power transmission system or the modulation process is in the logic "1" state.

[0056] In a specific embodiment, if Figure 3 As shown, the signal extraction unit 200 includes a diode switch series branch formed by a diode D1 and a switch tube Q1 connected in series, and the diode switch series branch is connected between the input end and the output end of the signal extraction unit 200, wherein the anode of the diode D1 is used to connect the input end of the signal extraction unit 200, and the cathode of the diode D1 is used to connect the output end of the signal extraction unit 200.

[0057] Specifically, Figure 3 As shown, the anode of the diode D1 is connected to the input end of the signal extraction unit 200 , the cathode of the diode D1 is connected to the first end of the switch tube Q1 , and the second end of the switch tube Q1 forms the output end of the signal extraction unit 200 .

[0058] See also Figure 5 Another embodiment of the present application shown Figure 1 Schematic diagram of the demodulation device of the wireless power transmission system in FIG. Figure 3 The difference is that the first end of the switch tube Q1 is connected to the input end of the signal extraction unit 200 , the second end of the switch tube Q1 is connected to the anode of the diode D1 , and the cathode of the diode D1 forms the output end of the signal extraction unit 200 .

[0059] In specific implementation, Figure 3 and Figure 5As shown, the control end of the switch tube Q1 receives the switch control signal PWM through the resistor R5. In actual implementation, the frequency of the switch control signal is the same as the frequency of the sine wave signal Vsin, and the duty cycle of the switch control signal is about 50%. Figure 4 The waveform PWM of the switching control signal is shown in .

[0060] Furthermore, Figure 3 and Figure 5 As shown, the control end of the switch tube Q1 is also grounded through a resistor R6.

[0061] In actual implementation, the switch control signal PWM may come from a controller, such as a controller MCU of the wireless power transmission system.

[0062] In actual implementation, the switch control signal PWM may also come from the transmitter 10. Figure 2 , the switch control signal PWM is a voltage signal at the second end of the first resonant capacitor Cp, wherein the second end of the first resonant capacitor Cp is used to connect the switch unit (such as Figure 2 At the second common node SW2 of the full-bridge inverter switch unit in the embodiment, the first end of the first resonant capacitor Cp is used to connect the first end of the first coil Lp. Figure 2 In the embodiment shown, the second end of the first coil Lp is used to connect the switch unit (such as Figure 2 The first common node SW1 of the full-bridge inverter switch unit).

[0063] In another embodiment, reference may be made to Figure 2 , the switch control signal PWM is a voltage signal at the second end of the first coil Lp, wherein the second end of the first coil Lp is used to connect the full-bridge inverter switch unit (such as Figure 2 The first common node SW1 of the full-bridge inverter switch unit).

[0064] As for the full-bridge inverter switch unit, we know that the voltage of the first common node SW1 and the second common node SW2 is a square wave signal with the same frequency as the sine wave signal Vsin, and the duty cycle is about 50%. That is, the inherent signal in the wireless power transmission system is used as the switch control signal, which simplifies the difficulty of design.

[0065] When the switch unit is a half-bridge inverter switch unit or a push-pull inverter switch unit, the switch control signal PWM can come from a common node that can provide a square wave signal with the same frequency as the sine wave signal Vsin and a duty cycle of about 50%.

[0066] In actual implementation, the switch control signal PWM and the sine wave signal Vsin with a DC offset are high-frequency signals, such as 360KHz signals.

[0067] Furthermore, in one embodiment, please refer to Figure 3 or Figure 5 The signal processing unit 300 includes a third resistor-capacitor parallel branch connected between the output terminal and the ground terminal of the signal extraction unit 200. Specifically, the third resistor-capacitor parallel branch includes a resistor R7 and a capacitor C3 connected in parallel.

[0068] Please combine Figure 4 , when the switch control signal PWM is at a high level, the switch tube Q1 is turned on, and when the amplitude of the sine wave signal Vsin with a DC offset is greater than the voltage of the node d1 of the third resistor-capacitor parallel branch connected to the signal extraction unit 200, that is, when the voltage at the anode end of the diode D1 is greater than the voltage at the cathode end thereof, the diode D1 is turned on, and the sine wave signal Vsin is transmitted to the output end of the signal extraction unit 200, as shown in FIG. Figure 4 The shaded portion shown is the period from t1 to t2.

[0069] During the period when the switch control signal PWM is at a low level, the switch tube Q1 is turned off, or when the amplitude of the sine wave signal Vsin with a DC offset is less than the voltage at the node d1, that is, the voltage at the anode end of the diode D1 is less than the voltage at the cathode end, the sine wave signal Vsin is blocked, and the output end of the signal extraction unit 200 outputs an approximate DC current. Specifically, the voltage is clamped at the voltage at the node d1, such as Figure 5 The low voltage DC output section shown in FIG. 1 is during the period from t2 to t3. In this way, the Figure 5 The high frequency intermediate signal Vmid is shown.

[0070] According to the above description, the frequency of the high-frequency intermediate signal Vmid is the same as the frequency of the sine wave signal Vsin with a DC offset and the frequency of the switch control signal PWM, for example, both are high-frequency signals of 360 kHz.

[0071] According to the conduction characteristics of the diode D1, and the fact that the switching control signal PWM has the same frequency as the sine wave signal Vsin and the duty cycle of the switching control signal is approximately 50%, it can be known that the high-frequency intermediate signal Vmid includes the peak information and phase information of the sine wave signal Vsin, that is, the signal extraction unit 200 extracts the peak information and phase information of the sine wave signal Vsin with a DC offset.

[0072] We know that when the wireless power transmission system works in the modulation state, the introduction of the fundamental wave will cause the peak value change or phase shift of the modulation signal or carrier signal, that is, the sinusoidal signal Vsin with DC offset. The signal extraction unit 200 of the present application extracts the peak value information and phase information of the sinusoidal signal Vsin with DC offset to form a high-frequency intermediate signal Vmid, and is used for subsequent signal processing of the demodulation device. Then, no matter the peak value change or phase shift of the sinusoidal signal Vsin with DC offset, it can be reflected in the high-frequency intermediate signal Vmid, specifically, the area of ​​the shaded part of the high-frequency intermediate signal Vmid changes, and after subsequent signal processing, it will be reflected in the output signal of the demodulation device 12, thereby achieving effective and reliable demodulation.

[0073] Specifically, Figure 4 As shown, relative to the normal working state (a), when in the modulation state (b), the phase of the sinusoidal wave signal Vsin with a DC offset is shifted backward, and the area of ​​the shaded portion becomes larger. After subsequent signal processing, the output signal of the demodulation device 12 will also become larger, thereby achieving effective and reliable demodulation.

[0074] Similarly, if the peak value increases or decreases, or the phase shifts forward, the area of ​​the shaded portion can change, which can affect the output signal of the demodulation device 12. Therefore, in the modulation state, the changes of the modulation signal relative to the normal state can be detected. Especially when lightly loaded, phase changes often occur, and the demodulation device 12 of the present application will be able to achieve effective and reliable demodulation.

[0075] See also Figure 6 shown Figure 3 and Figure 5 The circuit diagram of the signal processing unit in FIG. Figure 6 As shown, the signal processing unit 300 includes: a bandpass filter unit 310, used to convert the high-frequency intermediate signal Vmid into a first low-frequency intermediate signal Vd1, wherein the bandpass filter unit 310 includes a resistor-capacitor parallel branch connected between the output end of the signal extraction unit 200 and the ground end; a low-frequency signal amplifier unit 320, used to amplify the first low-frequency intermediate signal Vd1 to form a second low-frequency intermediate signal Vd2; a comparator unit 330, used to form a low-frequency square wave signal Vm according to the second low-frequency intermediate signal Vd2.

[0076] like Figure 6 As shown, the bandpass filter unit 310 is implemented as a low-pass filter, such as a 13 kHz low-pass filter, and the 360 ​​kHz high-frequency intermediate signal Vmid can be converted into a first low-frequency intermediate signal Vd1 lower than 13 kHz to be suitable for the frequency of the modulation signal. That is, the bandpass filter unit 310 converts the high-frequency intermediate signal Vmid into a low-frequency intermediate signal.

[0077] In a specific embodiment, the bandpass filter unit 310 includes a resistor R8 and a capacitor C4 connected in series between the input and output ends of the bandpass filter unit 310, in addition to the resistor-capacitor parallel branch connected between the output end and the ground end of the signal extraction unit 200. Of course, the present application is not limited to this specific structure, as long as the high-frequency intermediate signal Vmid can be converted into a low-frequency intermediate signal. Those skilled in the art know that there may be many changes, alternatives and modifications according to different applications and design requirements.

[0078] In actual implementation, the voltage of node d1 is configured by configuring the size of resistor R8 and resistor R7. During the period when diode D1 is turned off, that is, between time t2 and t3, the DC offset sinusoidal wave signal Vsin is prevented from affecting the voltage of node d1 by the turned-off diode D1, and the voltage of node d1 is maintained close to a constant DC voltage by the third resistor-capacitor parallel branch.

[0079] like Figure 6 As shown, in a specific embodiment, the low-frequency signal amplifier unit 320 includes an amplifier 321, which has a non-inverting input terminal connected to the output terminal of the bandpass filter unit 310, a resistor R9 and a capacitor C5 are connected in series between the inverting input terminal and the ground terminal of the amplifier 321, and a resistor R10 is connected between the inverting input terminal and the output terminal of the amplifier 321, wherein the output terminal of the amplifier 321 constitutes the output terminal of the low-frequency signal amplifier unit 320.

[0080] In practical applications, the bandpass filter unit 310 outputs a low-frequency AC signal, such as a 2KHZ signal. The low-frequency signal amplifier unit 320 is configured to amplify the low-frequency AC signal to a predetermined level suitable for downstream processing. Specifically, in the modulation state, the magnitude of the predetermined level will reflect Figure 4 The area of ​​the shaded portion.

[0081] like Figure 6 As shown, in a specific embodiment, the comparator unit 330 includes a comparator 331, the output end of the low-frequency signal amplifier unit 320 is connected to the inverting input end of the comparator 331 through a resistor R12, and is connected to the non-inverting input end of the comparator 331 through a resistor R11, a capacitor C6 is connected between the inverting input end and the ground end of the comparator 331, and a capacitor C7 is connected between the non-inverting input end and the ground end of the comparator 331, wherein the output end of the comparator 331 constitutes the output end of the comparator unit 330.

[0082] In operation, the low frequency square wave signal Vm output by the comparator unit 330 is a signal suitable for operation and processing by a microprocessor.

[0083] In one embodiment of the present application, a demodulation method of a wireless power transmission system is provided. Figure 7 FIG. 1 is a flowchart of a demodulation method for a wireless power transmission system according to an embodiment of the present application, and please refer to the above Figures 1 to 6 , a demodulation method for a wireless power transmission system includes:

[0084] The signal conversion unit 100 is used to convert the voltage signal on the first resonant capacitor Cp into a sine wave signal Vsin with a DC offset, wherein the first resonant capacitor Cp is used to form a resonant cavity with the first coil Lp;

[0085] The signal extraction unit 200 is used to extract the peak information and the phase information of the sine wave signal Vsin with a DC offset to form a high-frequency intermediate signal Vmid;

[0086] The signal processing unit 300 is used to convert the high-frequency intermediate signal Vmid into a low-frequency square wave signal Vm.

[0087] In a specific embodiment, a diode switch series branch formed by a diode D1 and a switch tube Q1 connected in series is provided in the signal extraction unit 200, and the diode switch series branch is connected between the input end and the output end of the signal extraction unit 200; a switch control signal PWM having a frequency the same as that of the sinusoidal wave signal Vsin and a duty cycle of approximately 50% is provided to control the on and off of the switch tube Q1, and when the switch tube Q1 is turned on and the voltage at the anode end of the diode D1 is greater than the voltage at the cathode end of the diode D1, the sinusoidal wave signal Vsin is transmitted to the output end of the signal extraction unit 200, and when the switch tube Q1 is turned off or the voltage at the anode end of the diode D1 is less than the voltage at the cathode end of the diode D1, the sinusoidal wave signal Vsin is blocked to form a high-frequency intermediate signal Vmid.

[0088] Furthermore, a resistor-capacitor parallel branch connected between the output terminal of the signal extraction unit 200 and the ground terminal is provided in the signal processing unit 300 to provide a voltage applied to the cathode terminal of the diode D1 at the output terminal of the signal extraction unit 200 .

[0089] Furthermore, the switch control signal PWM comes from the common node of two switch tubes in the transmitter circuit 11 of the wireless power transmission system. Figure 2 The first common node SW1 or the second common node SW2 in.

[0090] We know that when the wireless power transmission system works in the modulation state, the introduction of the fundamental wave will cause the peak value change or phase shift of the modulation signal or carrier signal, that is, the sinusoidal signal Vsin with a DC offset. The signal extraction unit 200 of the present application extracts the peak value information and phase information of the sinusoidal signal Vsin with a DC offset to form a high-frequency intermediate signal Vmid, and uses it for subsequent signal processing. Then, no matter the peak value change or phase shift of the sinusoidal signal Vsin with a DC offset, it can be reflected in the high-frequency intermediate signal Vmid, specifically, the area of ​​the shaded part of the high-frequency intermediate signal Vmid changes, and after subsequent signal processing, it will be reflected in the output signal of the demodulation method, thereby achieving effective and reliable demodulation.

[0091] Its specific working principle and advantages are the same as those of the above-mentioned demodulation device, and will not be repeated here.

[0092] The demodulation device of the present application can be applied to typical wireless power transmission systems, such as Figure 1 The wireless power transfer system shown in FIG. Figures 2 to 6 Therefore, in one embodiment, a wireless power transmission system is also provided, including:

[0093] a transmitter coil Lp configured to be magnetically coupled to a receiver coil Ls;

[0094] A first resonant capacitor Cp is connected in series with the transmitter coil Lp and the transmitter circuit 11 of the wireless power transmission system; and

[0095] The demodulation device 12 comprises:

[0096] The signal conversion unit 100 comprises a first differential input terminal and a second differential input terminal respectively coupled to two ends of the first resonant capacitor Cp, and an output terminal outputting a sinusoidal wave signal Vsin with a DC offset;

[0097] The signal extraction unit 200 comprises an input terminal coupled to the output terminal of the signal conversion unit 100, the input terminal is used to receive the sinusoidal wave signal Vsin with a DC offset, and the signal extraction unit 200 is used to extract the peak information and phase information of the sinusoidal wave signal Vsin with a DC offset, so as to output a high-frequency intermediate signal Vmid at the output terminal of the signal extraction unit 200;

[0098] The signal processing unit 300 has an input terminal coupled to the output terminal of the signal extraction unit 200 and is used to output a low-frequency square wave signal Vm at an output terminal of the signal processing unit 300 according to the high-frequency intermediate signal Vmid.

[0099] More specifically, the signal extraction unit 200 includes a diode switch series branch formed by a diode D1 and a switch tube Q1 connected in series, and the diode switch series branch is connected between the input end and the output end of the signal extraction unit 200, wherein the anode of the diode D1 is used to connect the input end of the signal extraction unit 200, and the cathode of the diode D1 is used to connect the output end of the signal extraction unit 200; the signal processing unit 300 includes a resistor and capacitor parallel branch connected between the output end of the signal extraction unit 200 and the ground end, wherein the control end of the switch tube Q1 receives a switch control signal PWM, the frequency of the switch control signal PWM is the same as the frequency of the sinusoidal wave signal Vsin, and the duty cycle of the switch control signal is approximately 50%.

[0100] Furthermore, the switch control signal PWM comes from the common node of two switch tubes in the transmitter circuit 11 of the wireless power transmission system. Figure 2 The first common node SW1 or the second common node SW2 in.

[0101] In actual implementation, Figure 1 and Figure 2 The transmitter circuit 11 is connected to a power converter for converting the electric energy provided by the power source into electric energy suitable for processing by the transmitter circuit 11, so as to further improve the performance of the wireless power transmission system.

[0102] In actual implementation, Figure 1 and Figure 2 The receiver circuit 21 in the embodiment is connected to a power converter for converting the electric energy output by the receiver circuit 21 into electric energy suitable for use by a load.

[0103] In actual implementation, the power source can be any suitable energy storage device, such as a solar panel array, a rechargeable battery, a fuel cell, any combination thereof, and / or the like. The power source can also be a power adapter that converts mains power into direct current power.

[0104] In actual implementation, the load may refer to a series / parallel connected rechargeable battery and / or battery pack coupled to the receiver. In addition, the load may also be a downstream power converter, such as a battery charger.

[0105] In actual implementation, the above-mentioned power converter can be implemented as any suitable power conversion structure.

[0106] The above-mentioned resistor, capacitor and switch tube can be a single device or a device unit formed by connecting multiple devices in series or parallel.

[0107] Although the embodiments of the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims.

[0108] In addition, the scope of the present application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, material compositions, devices, methods, and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of this disclosure, processes, machines, manufactures, material compositions, means, methods, or steps that perform substantially the same functions currently exist or will later be developed or achieve substantially the same results as the corresponding embodiments described herein that can be used according to this disclosure. Therefore, the appended claims are intended to include such processes, machines, manufactures, material compositions, devices, methods, or steps within their scope.

Claims

1. A demodulation device applied to a wireless power transmission system, characterized in that: include: a signal conversion unit, comprising a first differential input terminal and a second differential input terminal respectively coupled to two ends of a first resonant capacitor, and an output terminal outputting a sinusoidal wave signal with a DC offset, wherein the first resonant capacitor is used to form a resonant cavity with the first coil; A signal extraction unit, comprising an input terminal coupled to the output terminal of the signal conversion unit to receive the sinusoidal wave signal with a DC offset, the signal extraction unit being used to extract peak information and phase information of the sinusoidal wave signal with a DC offset to output a high-frequency intermediate signal at the output terminal of the signal extraction unit; A signal processing unit has an input terminal coupled to the output terminal of the signal extraction unit, and is used to output a low-frequency square wave signal at the output terminal of the signal processing unit according to the high-frequency intermediate signal.

2. The demodulation device according to claim 1, characterized in that: in, The resonant cavity is a resonant cavity in a transmitter of a wireless power transmission system, wherein the first coil is used for magnetic coupling with the second coil.

3. The demodulation device according to claim 1, characterized in that: in, The signal conversion unit includes a differential amplifier, and the first differential input terminal and the second differential input terminal of the signal conversion unit are respectively a non-inverting input terminal and an inverting input terminal of the differential amplifier.

4. The demodulation device according to claim 1, characterized in that: in, The signal extraction unit includes a diode and a switch tube connected in series to form a diode switch series branch, and the diode switch series branch is connected between the input end and the output end of the signal extraction unit, wherein The anode of the diode is used to connect to the input end of the signal extraction unit, and the cathode of the diode is used to connect to the output end of the signal extraction unit.

5. The demodulation device according to claim 4, characterized in that: in, The control end of the switch tube receives a switch control signal, the frequency of the switch control signal is the same as the frequency of the sine wave signal, and the duty cycle of the switch control signal is about 50%.

6. The demodulation device according to claim 4, characterized in that: in, The control end of the switch tube receives a switch control signal, and the switch control signal is a voltage signal of the second end of the first resonant capacitor, wherein the second end of the first resonant capacitor is used to connect to a second common node of a switch unit, and the first end of the first resonant capacitor is used to connect to the first end of the first coil, or The switch control signal is a voltage signal at the second end of the first coil, wherein the second end of the first coil is used to connect to a first common node of a switch unit, wherein The first common node and the second common node are both common nodes of two switch tubes in the switch unit.

7. The demodulation device according to claim 4, characterized in that: in, The signal processing unit comprises a resistor-capacitor parallel branch connected between the output terminal of the signal extraction unit and a ground terminal.

8. The demodulation device according to claim 4, characterized in that: in, The signal processing unit comprises: a bandpass filter unit, configured to convert the high-frequency intermediate signal into a first low-frequency intermediate signal, wherein the bandpass filter unit comprises a resistor-capacitor parallel branch connected between an output terminal of the signal extraction unit and a ground terminal; a low-frequency signal amplifier unit, configured to amplify the first low-frequency intermediate signal to form a second low-frequency intermediate signal; A comparator unit is used to form the low-frequency square wave signal according to the second low-frequency intermediate signal.

9. A demodulation method for a wireless power transmission system, characterized in that: include: Using a signal conversion unit to convert a voltage signal on a first resonant capacitor into a sinusoidal wave signal with a DC offset, wherein the first resonant capacitor is used to form a resonant cavity with the first coil; Extracting peak information and phase information of the sine wave signal with DC offset using a signal extraction unit to form a high-frequency intermediate signal; The high frequency intermediate signal is converted into a low frequency square wave signal using a signal processing unit.

10. The demodulation method according to claim 9, characterized in that: in, A diode switch series branch formed by a diode and a switch tube connected in series is provided in the signal extraction unit, and the diode switch series branch is connected between the input end and the output end of the signal extraction unit; A switch control signal having a frequency the same as that of the sinusoidal wave signal and a duty cycle of approximately 50% is provided to control the on and off of the switch tube. During the period when the switch tube is on and the voltage at the anode end of the diode is greater than the voltage at the cathode end of the diode, the sinusoidal wave signal is transmitted to the output end of the signal extraction unit. During the period when the switch tube is off or the voltage at the anode end of the diode is less than the voltage at the cathode end of the diode, the sinusoidal wave signal is blocked to form the high-frequency intermediate signal.

11. The demodulation method according to claim 10, characterized in that: in, A resistor-capacitor parallel branch connected between the output terminal of the signal extraction unit and the ground terminal is provided in the signal processing unit to provide a voltage applied to the cathode terminal of the diode at the output terminal of the signal extraction unit.

12. The demodulation method according to claim 10, characterized in that: in, The switch control signal comes from a common node of two switch tubes in a transmitter circuit of the wireless power transmission system.

13. A wireless power transmission system, characterized in that: include: a transmitter coil configured to magnetically couple with the receiver coil; A first resonant capacitor, connected in series with the transmitter coil and the transmitter circuit of the wireless power transmission system; as well as The demodulation device comprises: a signal conversion unit, comprising a first differential input terminal and a second differential input terminal respectively used to be coupled to two ends of the first resonant capacitor, and an output terminal outputting a sinusoidal wave signal with a DC offset; A signal extraction unit, comprising an input end coupled to the output end of the signal conversion unit, the input end being used to receive the sinusoidal wave signal with a DC offset, the signal extraction unit being used to extract peak information and phase information of the sinusoidal wave signal with a DC offset, so as to output a high-frequency intermediate signal at the output end of the signal extraction unit; A signal processing unit has an input terminal coupled to the output terminal of the signal extraction unit, and is used to output a low-frequency square wave signal at the output terminal of the signal processing unit according to the high-frequency intermediate signal.

14. The wireless power transmission system according to claim 13, characterized in that: in, The signal extraction unit comprises a diode switch series branch formed by a diode and a switch tube connected in series, the diode switch series branch is connected between the input end and the output end of the signal extraction unit, wherein the anode of the diode is used to connect the input end of the signal extraction unit, and the cathode of the diode is used to connect the output end of the signal extraction unit; The signal processing unit includes a resistor-capacitor parallel branch connected between the output terminal of the signal extraction unit and the ground terminal, wherein The control end of the switch tube receives a switch control signal, the frequency of the switch control signal is the same as the frequency of the sine wave signal, and the duty cycle of the switch control signal is about 50%.

Images