WO2021159764A1 - 一种无线充电电路、无线充电方法、设备和系统 - Google Patents

一种无线充电电路、无线充电方法、设备和系统 Download PDF

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Publication number
WO2021159764A1
WO2021159764A1 PCT/CN2020/125829 CN2020125829W WO2021159764A1 WO 2021159764 A1 WO2021159764 A1 WO 2021159764A1 CN 2020125829 W CN2020125829 W CN 2020125829W WO 2021159764 A1 WO2021159764 A1 WO 2021159764A1
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WIPO (PCT)
Prior art keywords
voltage
circuit
crests
wireless charging
processing module
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PCT/CN2020/125829
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English (en)
French (fr)
Inventor
李跃超
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华为技术有限公司
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Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP20918236.9A priority Critical patent/EP4092862A4/en
Priority to JP2022548938A priority patent/JP7459271B2/ja
Priority to BR112022015944A priority patent/BR112022015944A2/pt
Priority to CN202080051492.0A priority patent/CN114144957B/zh
Priority to KR1020227031267A priority patent/KR20220139377A/ko
Publication of WO2021159764A1 publication Critical patent/WO2021159764A1/zh
Priority to US17/886,724 priority patent/US20220393515A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/60—Circuit arrangements or systems for wireless supply or distribution of electric power responsive to the presence of foreign objects, e.g. detection of living beings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
    • H02J50/12—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/70—Circuit arrangements or systems for wireless supply or distribution of electric power involving the reduction of electric, magnetic or electromagnetic leakage fields
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/0115—Frequency selective two-port networks comprising only inductors and capacitors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters

Definitions

  • This application belongs to the field of wireless charging technology, and in particular relates to a wireless charging circuit, a wireless charging method, equipment, and system.
  • Wireless charging refers to a device that uses the principle of electromagnetic wave induction to charge, and the principle is similar to that of a transformer.
  • the coil at the transmitting end is connected to a wired power supply and generates an electromagnetic signal.
  • the coil at the receiving end induces the electromagnetic signal at the transmitting end and converts it into the required direct current to charge the battery in the receiving end.
  • the Qi standard is a "wireless charging” standard launched by the Wireless Power Consortium (WPC). It has two major characteristics: convenience and versatility. With the development and popularization of wireless charging technology, many wireless charging products have emerged on the market, especially wireless charging products based on the WPC Qi standard have a large market share.
  • WPC Wireless Power Consortium
  • the transmitting end When wirelessly charging the receiving end, such as a mobile phone, the transmitting end needs to perform real-time detection and identification on the receiving end, and when the receiving end is identified, it starts to transmit energy in the wireless charging coil. At the same time, it is also necessary to detect the charging environment in the wireless charging coil. If there are foreign objects in the coil, such as bank cards, ID cards or other metal foreign objects, the magnetic field will generate eddy currents, causing these foreign objects to consume the energy in the wireless charging coil. Reduce the charging efficiency, and even cause fires and other accidents. Therefore, foreign object detection has become the primary issue to ensure the safety of the wireless charging process.
  • the present application provides a wireless charging circuit and a wireless charging method.
  • the wireless charging circuit can detect foreign objects and improve the accuracy of Q value detection. Specifically, this application discloses the following technical solutions:
  • embodiments of the present application provide a wireless charging circuit, which includes an oscillating circuit and a detection circuit connected in sequence; wherein, the oscillating circuit includes: a series-connected excitation voltage source Us, a full-bridge circuit, and an LC series circuit , Wherein the excitation voltage source Us is used to provide a stable voltage for the LC series circuit.
  • the full bridge circuit includes a first bridge arm and a second bridge arm connected in parallel, the first bridge arm includes a first switch tube Q1 and a third switch tube Q3, and the second bridge arm includes a second switch. Tube Q2 and a fourth switch tube Q4; the LC series circuit includes an inductance Lp and a resonant capacitor Cp connected in series, and one end of the LC series circuit is connected to the phase midpoint of the first bridge arm, and the other end is connected to the phase midpoint of the first bridge arm.
  • the phase midpoint of the second bridge arm is connected; the phase center of the LC series circuit is connected to the detection circuit, and is used to output a damped resonance voltage signal to the detection circuit.
  • the detection circuit includes a comparison module and a processing module.
  • the comparison module is configured to receive the resonance voltage signal output by the oscillation circuit and convert the resonance voltage signal into a digital square wave signal;
  • the processing module is used for Receiving the digital square wave signal, obtaining a damped oscillation resonant voltage attenuation waveform according to the on and off of the switching tubes Q1 to Q4, and obtaining a first parameter in the resonant voltage attenuation waveform that satisfies a first preset condition, And determining the quality factor Q according to the first parameter;
  • the first parameter includes the number of crests, the number of troughs, or the sum of the number of crests and the number of troughs.
  • the processing module is also used to detect foreign objects according to the quality factor Q, and obtain the detection result; wherein, the quality factor Q represents the ratio of the energy stored in the oscillation circuit to the energy loss per cycle, The larger the Q value, the smaller the loss of the charging circuit in the same cycle and the better the performance.
  • a full-bridge circuit including a first bridge arm and a second bridge arm is designed to realize the charging and discharging of the oscillating circuit by controlling the on and off of the switch tube in the full-bridge circuit, and
  • the detection circuit determines the number of crests, troughs, or the sum of the crests and troughs that meet the preset conditions according to the resonant voltage waveform output by the oscillation circuit, and calculates the quality factor Q, thereby realizing the detection of foreign objects using the Q value.
  • the comparison module includes a comparator, and further, the comparator is a voltage comparator, and one input terminal of the voltage comparator is connected to a reference power supply for obtaining a reference voltage; the other input terminal is connected to a reference power supply.
  • the output terminal of the oscillating circuit is connected to receive the resonant voltage generated by the oscillating circuit, and the output terminal of the comparator is connected to the processing module.
  • the comparator can also be replaced by other circuits, such as operational amplifiers.
  • the comparison module may also include other auxiliary control circuits, which are not limited in this embodiment.
  • the first preset condition is that in each oscillation period, the resonance voltage generated by the damped oscillation is greater than the reference voltage; wherein, when the phase-to-ground voltage of the LC series circuit reaches the required value When the amplitude voltage of the excitation voltage source Us, the oscillating circuit generates damped oscillation and generates the resonant voltage.
  • the first parameter includes the following three possible implementation manners:
  • the first parameter includes the number of crests, and the number of crests that meets the first preset condition is that the first switch tube Q1 of the first bridge arm is disconnected, and the third switch tube When Q3 is turned on, the second switching tube Q2 of the second bridge arm changes from on to off, and the fourth switching tube Q4 turns from off to on, the processing module outputs according to the comparison module
  • the digital square wave signal determines the number of wave crests that meet the first preset condition.
  • the first parameter includes the number of troughs
  • the number of troughs meeting the first preset condition is that the second switching transistor Q2 of the second bridge arm is turned off, and the fourth switching transistor
  • the processing module outputs according to the comparison module
  • the digital square wave signal determines the number of troughs that meet the first preset condition.
  • the first parameter includes the sum of the number of crests and the number of troughs, and the sum is the number of crests satisfying a first preset condition and all crests satisfying the first preset condition. State the sum of the number of peaks and valleys.
  • the processing module is specifically configured to determine, according to the first parameter, that the quality factor Q is:
  • n and n are both positive integers, and m ⁇ 1, U1 and U2 are any peak voltage or any valley voltage in the resonant voltage attenuation waveform.
  • the quality factor Q is:
  • n is the number of wave crests or the number of wave troughs.
  • the quality factor Q is:
  • n is the sum of the number of crests and the number of troughs.
  • the step size unit of the measurement is determined by m.
  • the larger the value of m the smaller the step size unit and the higher the measurement accuracy.
  • the first parameter is the sum of the number of crests and the number of troughs
  • the value of m is 2.
  • the measurement step size unit is reduced by one time, so that the accuracy of the Q value is improved Doubled, the ability to identify foreign objects is enhanced. For example, controlling the turn-on and turn-off of the four switch tubes in the full-bridge circuit makes the step length of the original measured Q value changed from an integer unit to 0.5 unit. As the step length unit becomes smaller, the measurement result is more accurate and more accurate. It can accurately determine whether there are foreign objects in the coil, thereby improving the accuracy of the measurement.
  • n is proportional to m
  • n is inversely proportional to 1/m
  • t1 and t2 can include the following 4 situations:
  • t1 is one peak moment of the oscillating waveform
  • t2 is another peak moment of the oscillating waveform
  • t1 is a peak moment of the oscillating waveform
  • t2 is a trough moment of the oscillating waveform
  • t1 is the moment of one trough of the oscillating waveform
  • t2 is the moment of the other peak of the oscillating waveform
  • t1 is the time of one trough of the oscillating waveform
  • t2 is the time of the other trough of the oscillating waveform
  • the embodiments of the present application also provide another wireless charging circuit, including: an oscillating circuit and a detection circuit connected in sequence; wherein, the oscillating circuit includes: a series-connected excitation voltage source Us, a half-bridge circuit, and an LC series connection A circuit, wherein the excitation voltage source Us is used to provide a stable voltage for the LC series circuit.
  • the half-bridge circuit includes a fifth switching tube Q5 and a sixth switching tube Q6 connected in series;
  • the LC series circuit includes an inductance Lp and a resonant capacitor Cp connected in series, and one end of the LC series circuit is connected to the half The phase midpoint of the bridge circuit is connected, and the other end is grounded; the phase center of the LC series circuit is connected to the detection circuit, and is used to output a damped resonance voltage signal to the detection circuit.
  • the detection circuit includes: a voltage bias module, a comparison module, and a processing module.
  • the voltage bias module is connected to the oscillating circuit for receiving the resonant voltage signal output by the oscillating circuit and combining the resonant voltage signal. The voltage signal is biased and then transmitted to the comparison module.
  • the comparison module receives and converts the biased resonant voltage signal into a digital square wave signal and outputs it to the processing module; the processing module is used to receive The digital square wave signal obtains the resonant voltage attenuation waveform of the damped oscillation according to the on and off of the switching tubes Q1 to Q4, and obtains the second parameter in the resonant voltage attenuation waveform that meets the second preset condition, according to The second parameter determines the quality factor Q, and the second parameter includes the sum of the number of crests and the number of troughs.
  • the processing module is also used to detect foreign objects according to the quality factor Q, and obtain the detection result; wherein the quality factor Q represents the ratio of the energy stored in the oscillation circuit to the energy loss per cycle.
  • a half-bridge circuit is included in the oscillating circuit design, and a half-period oscillating circuit can be generated by controlling the turning on and off of the fifth switching tube Q5 and the sixth switching tube Q6 in the half-bridge circuit, and
  • the comparison module is used to process the resonant voltage output by the oscillating circuit to obtain the second parameter and the oscillating frequency, and calculate the Q value, thereby realizing the detection of foreign objects in the wireless charging coil.
  • this circuit can also measure and obtain the sum of the number of crests and valleys of the half cycle, and then calculate the Q value.
  • the measurement step size unit is doubled, because The step size unit becomes smaller, so the measurement result is more accurate, and it can be more accurately judged whether there are foreign objects in the coil, so that the detection accuracy of the Q value is doubled, and the ability to identify foreign objects is enhanced.
  • the second preset condition is Uc+V ref 0 >V ref 1 , or Uc+V ref 0 ⁇ V ref 2 , where Uc is the resonance voltage generated by damped oscillation, and V ref 0 is the bias voltage, Uc+V ref 0 is the resonance voltage after the bias processing of the voltage bias module, V ref 1 is the first reference voltage, and V ref 2 is the second reference voltage; and, when the phase of the LC series circuit is in When the point-to-ground voltage reaches the amplitude voltage of the excitation voltage source Us, the oscillation circuit generates damped oscillation and generates the resonance voltage.
  • the sum of the number of crests and the number of troughs is that when the fifth switch Q5 changes from on to off, the sixth switch When the tube Q6 is turned off and turned on, the processing module determines the sum of the number of crests and the number of crests that meet the second preset condition according to the digital square wave signal output by the comparison module.
  • control of the switching tubes Q5 and Q6 can be performed by a control circuit connected to the switching tubes Q5 and Q6.
  • the switching tubes Q5 and Q6 are diodes, MOSFET tubes, or IGBTs, etc., and the control circuit is connected to each other.
  • the gates of the two switching tubes are connected to drive the switching tubes Q5 and Q6 to be turned on or off.
  • the input terminal of the comparison module is connected with the output terminal of the voltage bias module, and the output terminal is connected with the processing module.
  • the comparison module includes a first comparator and a second comparator.
  • both the first comparator and the second comparator include a first input terminal, a second input terminal, and an output terminal;
  • the first input terminal of the first comparator is connected to a first voltage source, and is used to obtain a first reference voltage provided by the first voltage source;
  • the second input terminal of the first comparator is connected to the second voltage source.
  • the first input terminal of the comparator is connected as the input terminal of the comparison circuit;
  • the second input terminal of the second comparator is connected with the second voltage source, and is used to obtain the second reference provided by the second voltage source. Voltage;
  • the output terminal of the first comparator is connected to the output terminal of the second comparator as the output terminal of the comparison module.
  • the first reference voltage and the second reference voltage may be positive or negative values.
  • the processing module is specifically configured to determine, according to the second parameter, that the quality factor Q is:
  • n and m are both positive integers, and m ⁇ 1, U 0 is the voltage amplitude of the excitation voltage source Us, ⁇ V is the voltage difference between the bias voltage and the reference voltage, and the reference voltage is the first Reference voltage or second reference voltage.
  • the quality factor Q is:
  • n is the sum of the number of crests and the number of troughs.
  • V ref 2 ⁇ Uc+V ref 0 ⁇ V ref 1 If V ref 2 ⁇ Uc+V ref 0 ⁇ V ref 1 , the second preset condition is not met, a high level is not generated, and a low level signal is output.
  • an embodiment of the present application also provides a wireless charging method, which is applied to a wireless charging circuit, and the circuit structure is the same as the structure of the wireless charging circuit described in the first aspect.
  • the wireless charging circuit includes an oscillation circuit and a detection circuit connected in sequence.
  • the oscillating circuit includes: a series excitation voltage source Us, a full bridge circuit, and an LC series circuit, wherein the excitation voltage source Us is used to provide a stable voltage for the LC series circuit;
  • the full bridge circuit includes a parallel connection
  • the first bridge arm includes a first switching tube Q1 and a third switching tube Q3, and the second bridge arm includes a second switching tube Q2 and a fourth switching tube Q4; so
  • the LC series circuit includes an inductance Lp and a resonant capacitor Cp connected in series, and one end of the LC series circuit is connected to the phase midpoint of the first bridge arm, and the other end is connected to the phase midpoint of the second bridge arm.
  • the phase midpoint of the LC series circuit is connected to the detection circuit for outputting a damped oscillation resonant voltage signal to the detection circuit;
  • the detection circuit includes a comparison module and a processing module, and the comparison module is used To receive the resonant voltage signal and convert the resonant voltage signal into a digital square wave signal.
  • the method includes:
  • the processing module receives the digital square wave signal, and the digital square wave signal is converted and generated by the resonant voltage signal.
  • the processing module obtains the resonant voltage attenuation waveform of the damped oscillation according to the on and off of the switch tubes Q1 to Q4, and obtains the first parameter that satisfies the first preset condition according to the resonant voltage attenuation waveform;
  • a parameter includes the number of crests, the number of troughs, or the sum of the number of crests and the number of troughs.
  • the processing module determines the quality factor Q according to the first parameter.
  • the processing module detects foreign objects according to the quality factor Q, and obtains the detection result.
  • the first preset condition is that in each oscillation period, the resonance voltage generated by the damped oscillation is greater than the reference voltage; when the phase-to-ground voltage of the LC series circuit reaches the excitation voltage source Us When the amplitude voltage is applied, the oscillating circuit generates damped oscillation and generates the resonant voltage.
  • the first parameter includes the number of crests, and the number of crests meeting the first preset condition is that the first switch tube Q1 of the first bridge arm is turned off, the third switch tube Q3 is turned on, and the second When the second switch tube Q2 of the bridge arm changes from on to off, and the fourth switch tube Q4 changes from off to on, the processing module according to the digital square wave signal output by the comparison module, The determined number of wave crests meeting the first preset condition.
  • the first parameter includes the number of troughs, and the number of troughs meeting the first preset condition is that the second switching tube Q2 of the second bridge arm is turned off, the fourth switching tube Q4 is turned on, and the first When the first switch tube Q1 of the bridge arm changes from on to off, and the third switch tube Q3 changes from off to on, the processing module according to the digital square wave signal output by the comparison module, The determined number of troughs satisfying the first preset condition.
  • the first parameter includes a sum of the number of crests and the number of troughs, and the sum is the number of crests that meet the first preset condition and the number of crests and troughs that meet the first preset condition Sum.
  • the processing module determining the quality factor Q according to the first parameter includes: the processing module determining the quality according to the first parameter The factor Q is:
  • n and m are both positive integers, and m ⁇ 1, U1 and U2 are any peak voltage or any valley voltage in the resonant voltage attenuation waveform.
  • the quality factor Q is:
  • n is the sum of the number of crests and the number of troughs.
  • the detecting foreign objects includes: if the quality factor Q is less than or equal to a first threshold, determining that there is a foreign object in the wireless charging coil; If the factor Q is greater than the first threshold and less than or equal to the second threshold, it is determined that there may be foreign objects in the wireless charging coil, and further inspection is required; if the quality factor Q is greater than the second threshold, it is determined that there are no foreign objects in the wireless charging coil.
  • the first threshold and the second threshold can be set by themselves.
  • the embodiments of the present application also provide another wireless charging method, which is applied to a wireless charging circuit, and the circuit structure is the same as the structure of the wireless charging circuit described in the second aspect.
  • the wireless charging circuit includes an oscillation circuit and a detection circuit connected in sequence.
  • the oscillating circuit includes: a series-connected excitation voltage source Us, a half-bridge circuit, and an LC series circuit, wherein the excitation voltage source Us is used to provide a stable voltage for the LC series circuit;
  • the half-bridge circuit includes a series connection The fifth switching tube Q5 and the sixth switching tube Q6;
  • the LC series circuit includes a series inductor Lp and a resonant capacitor Cp, and one end of the LC series circuit is connected to the phase midpoint of the half-bridge circuit, and the other One end is grounded;
  • the phase midpoint of the LC series circuit is connected to the detection circuit for outputting a damped resonance voltage signal to the detection circuit;
  • the detection circuit includes: a voltage bias module, a comparison module, and a processing Module, the voltage bias module receives the resonant voltage signal, and transmits the resonant voltage signal to the comparison module after bias processing; the comparison module receives and converts the biased resonant voltage signal Into a digital square wave signal, and
  • the method includes:
  • the processing module receives the digital square wave signal.
  • the processing module obtains the resonant voltage attenuation waveform of the damped oscillation according to the on and off of the switching tubes Q1 to Q4, and obtains the second parameter that satisfies the second preset condition in the resonant voltage attenuation waveform, the second The parameter includes the sum of the number of crests and the number of troughs, and the processing module determines the quality factor Q according to the second parameter.
  • the processing module is also used to detect foreign objects according to the quality factor Q, and obtain the detection result.
  • the second preset condition is Uc+V ref 0 >V ref 1 , or Uc+V ref 0 ⁇ V ref 2 , where V ref 1 is the first reference voltage, and V ref 2 is the second reference Voltage, V ref 0 is the bias voltage, Uc is the resonant voltage generated by the damped oscillation, and Uc+V ref 0 is the resonant voltage after the bias processing of the voltage bias module.
  • the oscillating circuit When the phase-to-ground voltage of the LC series circuit reaches the amplitude voltage of the excitation voltage source Us, the oscillating circuit generates damped oscillation and generates the resonant voltage.
  • the sum of the number of crests and the number of troughs is that when the fifth switch Q5 changes from on to off, the sixth switch When the tube Q6 is turned off and turned on, the processing module determines the sum of the number of crests and the number of crests that meet the second preset condition according to the digital square wave signal output by the comparison module .
  • the processing module determining the quality factor Q according to the second parameter includes: the processing module determining the quality according to the second parameter The factor Q is:
  • n and m are both positive integers, and m ⁇ 1, U 0 is the voltage amplitude of the excitation voltage source Us, ⁇ V is the voltage difference between the bias voltage and the reference voltage, and the reference voltage is the first reference voltage or The second reference voltage.
  • the quality factor Q is:
  • n is the sum of the number of crests and the number of troughs.
  • an embodiment of the present application also provides a processing device.
  • the processing device includes a processor and a memory, and the processor is coupled with the memory. Further, the processor is configured to run or execute computer program instructions stored in the memory, and call data in the memory to execute the methods described in various implementation manners of the third aspect or the fourth aspect, And according to the Q value, it is detected whether there is a foreign object in the charging coil.
  • the processor is a processing chip or a processing module.
  • the processor is a random access memory RAM, or a non-volatile memory, such as flash memory, hard disk, etc.
  • an embodiment of the present application also provides a device, the device is a sending device or a receiving device, the sending device or the receiving device includes the foregoing first aspect and the wireless charging circuit in various implementations of the first aspect , And the wireless charging circuit implements the methods described in the foregoing second aspect and various implementation manners of the second aspect, and detects foreign objects.
  • the detection process includes: judging the relationship between the quality factor Q value and the first threshold and the second threshold.
  • the quality factor Q is less than or equal to the first threshold, it is determined that there is a foreign object in the wireless charging coil.
  • the quality factor Q is greater than the first threshold and less than or equal to the second threshold, it is determined that there may be foreign objects in the wireless charging coil, and further inspection is required.
  • an embodiment of the present application also provides a wireless charging system.
  • the system includes a transmitting device and a receiving device.
  • the transmitting device includes the wireless charging circuit described in the first or second aspect.
  • the device is a device to be charged.
  • the receiving device also includes the wireless charging circuit described in the first aspect or the second aspect, and implements a foreign object detection function.
  • the embodiments of the present application also provide a computer-readable storage medium.
  • the storage medium stores instructions. When the instructions run on a computer or a processor, they are used to execute the foregoing third aspect or the first aspect. Methods in various implementations in the four aspects.
  • the computer program product includes computer instructions. When the instructions are executed by a computer or a processor, the methods in the foregoing third aspect or the fourth aspect can be implemented. .
  • FIG. 1 is a schematic structural diagram of a wireless charging circuit provided by an embodiment of the application
  • FIG. 2 is a schematic structural diagram of another wireless charging circuit provided by an embodiment of the application.
  • FIG. 3 is a schematic structural diagram of a full bridge circuit provided by an embodiment of the application.
  • FIG. 4a is a flowchart of a method for determining a Q value provided by an embodiment of the application
  • FIG. 4b is a flowchart of a method for determining the number of crests according to an embodiment of the application
  • Fig. 5a is an equivalent circuit diagram of a resonant circuit provided by an embodiment of the application.
  • 5b is a schematic diagram of a resonant voltage attenuation waveform generated by an oscillating circuit provided by an embodiment of the application;
  • Fig. 6a is an equivalent circuit diagram of another resonant circuit provided by an embodiment of the application.
  • 6b is a schematic diagram of a resonant voltage attenuation waveform generated by another oscillator circuit provided by an embodiment of the application;
  • FIG. 7 is a schematic structural diagram of another wireless charging circuit provided by an embodiment of the application.
  • FIG. 8 is a flowchart of another method for determining a Q value provided by an embodiment of the application.
  • FIG. 9 is a schematic diagram of another resonant voltage attenuation waveform generated by an oscillating circuit according to an embodiment of the application.
  • FIG. 10 is a schematic structural diagram of yet another wireless charging circuit provided by an embodiment of the application.
  • FIG. 11 is a schematic diagram of another resonant voltage attenuation waveform generated by an oscillating circuit according to an embodiment of the application.
  • FIG. 12 is a schematic structural diagram of a processing module provided by an embodiment of this application.
  • the technical solution of this application is applied to the wireless charging technology scenario.
  • This scenario includes wireless charging devices and devices to be charged.
  • the wireless charging device is used to charge a device to be charged with a wireless charging function.
  • the wireless charging device may be a wireless charging type mobile power supply, a wireless charging pad, a wireless charger, and the like.
  • Devices to be charged include electronic devices with built-in rechargeable batteries, such as mobile phones, tablets, notebook computers, vehicle-mounted devices, and digital cameras.
  • the wireless charging device may also be called a sending device, and the device to be charged may also be called a receiving device.
  • a wireless charging device includes a housing, a wireless charging coil, a carrying device, and the like.
  • the surface of the casing is provided with a charging surface for carrying the device to be charged. Therefore, the device to be charged can be placed on the charging surface of the casing.
  • a battery and a circuit board are also arranged in the casing, and the battery is used to store electrical energy and output electrical energy to the outside.
  • a wireless charging circuit is provided on the circuit board, and the wireless charging circuit is electrically connected to the wireless charging coil for controlling the charging and discharging process of the wireless charging device and controlling the working state of the entire wireless charging device.
  • the wireless charging coil is arranged in the casing and is used to convert the electric energy of the battery into magnetic energy for transmission and transmission.
  • the carrying device is arranged in the housing, used for carrying and fixing the wireless charging coil, and protecting the wireless charging coil.
  • the embodiment of the present application mainly solves the technical problem of how to detect whether the charging environment is good when the electromagnetic wave induction principle is used to charge the device to be charged, that is, whether the wireless charging coil has foreign matter, which affects the charging quality.
  • an embodiment of the present application provides a method for determining the quality factor Q (or “Q value”), where the quality factor represents an energy storage device (such as an inductor, a capacitor, etc.), a resonant circuit
  • the Q value of the reactance element in the series resonant circuit is equal to the ratio of its reactance to its equivalent series resistance, and the larger the Q value of the element, the smaller the loss of the circuit or network composed of the element, the better the performance, so the quality factor Q is available To evaluate the size of the loop loss.
  • the range of Q value is in the range of tens to hundreds.
  • the Q value can be obtained by the damped oscillation method. Specifically, the Q value is determined by designing a wireless charging circuit to obtain the attenuation waveform of the resonant voltage generated when the LC series circuit is damped and oscillated.
  • the following embodiments describe in detail a wireless charging circuit in the wireless charging device.
  • the circuit includes an oscillating circuit 10 and a detection circuit 20, wherein the oscillating circuit 10 includes: a power supply 1001 connected in sequence, a detection control Circuit 1002, LC series circuit 1003; the detection circuit 20 includes a comparison module 2001 and a processing module 2002.
  • the power source 1001 may be an excitation voltage source Us, which is used to provide voltage to the oscillation circuit 10.
  • the detection control circuit 1002 is connected in series with the power supply 1001 and the LC series circuit 1003 for detecting voltage and controlling the charging and discharging of the LC series circuit 1003.
  • the detection control circuit 1002 includes at least one light switch, the light switch includes a switch, a diode, a metal-oxide semiconductor field effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), etc., or ,
  • the switch tube may also include other materials.
  • the LC series circuit 1003 outputs a resonant voltage signal during the damping oscillation process, and the resonant voltage signal is output to the comparison module 2001 and the processing module 2002.
  • the comparison module 2001 and the processing module 2002 process the resonant voltage signal and calculate Calculate the Q value, and use the Q value to realize the detection of foreign objects.
  • each circuit component in the wireless charging circuit may include the following specific implementation manners.
  • this embodiment provides a schematic structural diagram of another wireless charging circuit.
  • the circuit includes: an oscillation circuit 10 and a detection circuit 20, and the oscillation circuit 10 is connected to the detection circuit 20. Further, the oscillation circuit 10 It includes: an excitation voltage source Us, a full bridge circuit, an LC series circuit, and the equivalent impedance R of the LC series circuit. The equivalent impedance R is not shown in FIG. 2. Wherein, the voltage amplitude of the excitation voltage source Us is U 0 .
  • the wireless charging circuit also includes a charging control resistor R0, which is used to suppress the oscillation of the circuit oscillation 10 when the LC series circuit is charged.
  • the full bridge circuit includes a first bridge arm 11 and a second bridge arm 12 connected in parallel, and the first bridge arm 11 includes a first switching tube Q1 and a third switching tube Q3,
  • the second bridge arm 12 includes a second switching tube Q2 and a fourth switching tube Q4; and Q1 is connected in series with Q3, and Q2 is connected in series with Q4, the phase midpoint of the first bridge arm 11 is O1, and the phase of the second bridge arm 12 The midpoint is O2.
  • the potentials at both ends of the phase midpoint of each bridge arm are equal.
  • One end of the full bridge circuit is connected to the positive electrode of the excitation voltage source Us through the charge control resistor R0, and the other end is connected to the negative electrode of the excitation voltage source Us.
  • the excitation voltage source Us is used to provide a stable voltage for the LC series circuit.
  • the function of the detection control circuit 1002 shown in FIG. 1 is implemented by the full bridge circuit in this embodiment, and the full bridge circuit can be used to control the excitation voltage source Us to charge and discharge the LC series circuit.
  • the LC series circuit includes an inductor Lp and a resonant capacitor Cp connected in series, the inductor Lp and the resonant capacitor Cp are connected in series, and the phase midpoint of the inductor Lp and the resonant capacitor Cp is M.
  • the LC series circuit also includes an equivalent impedance R, which is not shown in FIG. 2.
  • the LC series circuit is connected to the full bridge circuit. Specifically, the phase midpoint O1 of the first bridge arm of the full bridge circuit is connected to one end of the LC series circuit, and the second bridge arm of the full bridge circuit is The phase midpoint O2 is connected to the other end of the LC series circuit.
  • the voltage of the phase midpoint M of the LC series circuit to the ground (GND) is Uc, and the pin output by the phase midpoint M is connected to the detection circuit 20.
  • the detection circuit 20 includes: a comparison module and a processing module.
  • the comparison module includes a comparator, which can be represented by "Com". Further, the comparator Com is a voltage comparator. The comparison module in this embodiment is described by taking the comparator Com as an example.
  • the comparator includes a first input terminal (also called input terminal 1), a second input terminal (also called input terminal 2) and an output terminal.
  • the input terminal 1 is a non-inverting input terminal +
  • the input terminal 2 is an inverting input terminal -.
  • the input terminal 1 is connected to the output pin of the phase midpoint M of the LC series circuit
  • the input terminal 2 is connected to a reference power supply, and the reference power supply provides a reference voltage;
  • the output terminal of the comparator is connected to the processing module.
  • the reference voltage may be expressed as "Vref", and the reference voltage value may be a positive value or a negative value.
  • the comparator is used to obtain the resonant voltage signal output when the damped oscillation of the oscillating circuit occurs, and convert the resonant voltage signal (that is, the voltage Uc between the phase midpoint M of the LC series circuit and the ground) into a digital square wave signal, and Transfer to the processing module.
  • the processing module is connected to the output terminal of the comparator, and is used to receive the digital square wave signal output by the comparator, obtain the damped oscillation resonant voltage attenuation waveform according to the on and off of the switching tubes Q1 to Q4, and obtain the The first parameter in the resonant voltage attenuation waveform that satisfies the first preset condition, the quality factor Q is determined according to the first parameter, and the foreign object is detected according to the quality factor Q, and the detection result is obtained.
  • the quality factor Q represents the ratio of the energy stored in the oscillating circuit to the energy lost per cycle. The larger the Q value, the smaller the loss and the better the charging effect.
  • the first preset condition is that in each oscillation period, the resonance voltage generated by the damped oscillation is greater than the reference voltage.
  • the oscillating circuit When the voltage of the phase midpoint M of the LC series circuit with respect to ground reaches the amplitude voltage of the excitation voltage source Us, the oscillating circuit generates damped oscillation and generates the resonant voltage.
  • the first parameter includes the number of crests, the number of troughs, or the sum of the number of crests and the number of troughs.
  • other parameters can also be included. Specifically, the following three implementation modes are included:
  • the first parameter is the number of crests.
  • the method includes:
  • the processing module obtains the number of wave crests that meet the first preset condition. Wherein, the number of crests is represented by "n1".
  • step 401 includes:
  • the first switching tube Q1 in the first bridge arm is controlled to be turned off, and the third switching tube Q3 is turned on; at the same time, the second switching tube Q2 in the second bridge arm is controlled to be turned on, and the fourth switching tube Q4 is turned off.
  • the oscillating circuit forms a first loop: Us ⁇ Q2 ⁇ Cp ⁇ Lp ⁇ Q3 ⁇ ground GND ⁇ Us, and the excitation voltage source Us charges the capacitor Cp.
  • the oscillating circuit forms a second loop: GND ⁇ Q3 ⁇ Lp ⁇ Cp ⁇ Q4 ⁇ GND, LC
  • the capacitance Cp of the series circuit is discharged.
  • the equivalent circuit is shown in Figure 5a.
  • Q3 When the Q3 is controlled to be turned on, Q4 is turned on, and Q2 is turned off, it is equivalent to turning the switch K in the equivalent circuit from contact a to contact b (t>0) , Forming the second loop.
  • the LC series circuit outputs the resonance voltage Uc to the comparator.
  • the resonant voltage starts to decay from the amplitude voltage U 0.
  • step 4011 and step 4012 can be performed by a control circuit connected to the switching tubes Q1 to Q4.
  • the switching tubes Q1 to Q4 are all MOSFET tubes, and the control circuit is connected to the gate of each MOSFET tube.
  • the driving switches Q1 to Q4 are turned on or off.
  • the comparator obtains the resonant voltage signal Uc output by the oscillation circuit, converts the resonant voltage signal Uc into a digital square wave signal, and transmits it to the processing module.
  • the comparator is used to compare the size of the resonant voltage signal output by the oscillating circuit in each oscillation period with the reference voltage. Further, it is determined whether the resonance voltage Uc generated by the damped oscillation is greater than the reference voltage Vref in each oscillation period, and if it is, the first preset condition is satisfied; otherwise, it is not satisfied.
  • Fig. 5b a schematic diagram of the attenuation waveform of the resonant voltage generated by an oscillating circuit.
  • the excitation voltage source Us generates a first-step excitation signal e(t).
  • the output resonant voltage Uc gradually decays within a certain period of time.
  • the wave line in Figure 5b indicates the resonance.
  • Voltage decay curve, the square wave line represents the digital square wave signal after conversion.
  • the frequency of the oscillation period is f1. In each oscillation period (1/f1), if the output resonant voltage Uc>Vref generated by the damped oscillation, the Vref is a DC level.
  • the DC level is set to one With a positive level, a square wave signal is generated, and a rising edge of the square wave appears, and the starting moment of the rising edge is the intersection of the resonance voltage attenuation curve and the reference voltage. If Uc ⁇ Vref, no square wave signal will be generated, and the damped oscillation tends to end. In the resonant voltage attenuation curve, the number of crests meeting the first preset condition is the same as the number of rising edges in the square wave waveform.
  • the processing module receives the digital square wave signal from the comparator, obtains the damped oscillation resonant voltage attenuation waveform according to the on and off of the switching tubes Q1 to Q4, and obtains the first preset condition in the resonant voltage attenuation waveform The number of crests is n1.
  • the resonance voltage Uc output by the LC series circuit gradually decreases from the amplitude voltage U 0 to 0, and the processing module determines according to the digital square wave signal output by the comparator
  • the first parameter is the number of troughs.
  • the method includes:
  • the processing module obtains the number of troughs meeting the first preset condition.
  • the number of troughs is represented by "n2".
  • the method of obtaining the number of troughs n2 is similar to the method of obtaining the number of crests n1 in step 401. Specifically:
  • the first switching tube Q1 in the first bridge arm is controlled to be turned on, and the third switching tube Q3 is turned off; at the same time, the second switching tube Q2 in the second bridge arm is controlled to be turned off, and the fourth switching tube Q4 is turned on.
  • the oscillating circuit forms a third loop: Us ⁇ Q1 ⁇ Lp ⁇ Cp ⁇ Q4 ⁇ GND ⁇ Us.
  • the excitation voltage source Us charges the capacitor Cp.
  • the switching tubes Q1 to Q4 in the full bridge circuit are controlled to make the LC series circuit discharge and oscillate.
  • the circuit begins to dampen the oscillation.
  • the resonance voltage signal Uc is the amplitude voltage U 0
  • the third switching tube Q3 in the first bridge arm is controlled to be turned on, the first switching tube Q1 is turned off, and the second bridge is maintained
  • the second switch tube Q2 in the arm is turned off, and the fourth switch tube Q4 remains on state.
  • the oscillation circuit forms a fourth loop: GND ⁇ Q3 ⁇ Lp ⁇ Cp ⁇ Q4 ⁇ GND, the LC series circuit
  • the capacitor Cp is discharged.
  • the equivalent circuit is shown in Figure 6a.
  • Q3 When Q3 is controlled to be turned on, Q4 is turned on, Q1 is turned off, and Q2 is turned off, it is equivalent to turning the switch K in the equivalent circuit from contact a to contact b( t>0), forming the fourth loop.
  • the LC series circuit outputs a resonance voltage signal Uc to the comparator.
  • the comparator obtains the resonant voltage signal Uc output by the oscillating circuit, converts the resonant voltage signal Uc into a digital square wave signal, and transmits it to the processing module.
  • the comparator is used to compare the magnitude of the voltage signal Uc output by the oscillating circuit with the reference voltage Vref in each oscillation period.
  • Figure 6b it is a schematic diagram of the attenuation waveform of the resonant voltage output by the oscillation circuit.
  • the excitation voltage source Us generates a first-step excitation signal e(t). After the attenuated oscillation signal of the LC oscillation circuit passes through the voltage comparator, the output voltage gradually decays within a certain period of time.
  • the wave line in Figure 6b represents the resonant voltage
  • the attenuation waveform curve is symmetrical with the waveform shown in Figure 5b about the horizontal axis, and the square wave line represents the converted digital square wave signal.
  • the frequency corresponding to the oscillation period is f2.
  • the resonance voltage Uc>Vref produced by the damped oscillation a square wave signal is generated and a rising edge of the square wave appears. If Uc ⁇ Vref, no square wave signal will be generated, and the damped oscillation tends to end.
  • the waveform shown in Figure 6b is the number of peaks that satisfy the first preset condition, which is equivalent to the number of troughs of the attenuation waveform shown in Figure 5b, and the number of troughs is equal to the number of rising edges in the square waveform generated. same.
  • the processing module receives the digital square wave signal from the comparator, and determines the trough number n2 according to the digital square wave signal.
  • the first parameter is the sum of the number of crests and the number of troughs.
  • the method includes:
  • the processing module obtains the sum of the number of crests and the number of troughs.
  • the sum (or total) can be represented by n.
  • n n1+n2, and the oscillation frequency f ⁇ f1 ⁇ f2.
  • the process of obtaining these parameters may also be included.
  • the processing module determines the quality factor Q according to the sum n (the first parameter) of the number of crests and the number of troughs.
  • the input source of the LC series circuit is the excitation voltage source Us
  • the output DC voltage amplitude is U 0
  • the voltage when the capacitor Cp is full is U 0 .
  • Q value the quality factor Q of the resonant circuit
  • the resonance conditions are:
  • ⁇ 0 is the angular frequency
  • f 0 is the frequency
  • n is a natural number, that is, n ⁇ 0
  • the above formula (8) is When n is an odd number, u(t) is a negative peak, and when n is an even number, u(t) is a positive peak.
  • t1 and t2 are the moments of any two peaks or valleys in the resonant voltage attenuation waveform.
  • t1 is a peak moment of the oscillating waveform
  • t2 is another peak moment of the oscillating waveform
  • t1 is a peak moment of the oscillating waveform
  • t2 is a trough moment of the oscillating waveform
  • t1 is a trough of the oscillation waveform
  • t2 is another peak time of the oscillating waveform
  • t1 is a trough time of the oscillating waveform
  • t2 is another trough time of the oscillating waveform.
  • m and n are both positive integers, and m ⁇ 1, Q is the quality factor, the time corresponding to the voltage U1 of a certain peak or trough of the oscillation waveform is t1, and the time corresponding to the voltage U2 of a certain peak or trough is t2. If U1 or U2 is the trough voltage, it is a negative value; If U1 or U2 is a peak voltage, it is a positive value. And, when the Q value is constant, n is proportional to m, and n is inversely proportional to 1/m.
  • the processing module detects the foreign object according to the quality factor Q, and obtains the detection result.
  • a detection method is to set two thresholds, namely a first threshold and a second threshold, and the first threshold is smaller than the second threshold.
  • the quality factor Q is less than or equal to the first threshold, it is determined that there is a foreign object in the wireless charging coil.
  • the quality factor Q is greater than the first threshold and less than or equal to the second threshold, it is determined that there may be foreign objects in the wireless charging coil, and further inspection is required.
  • the Q value is:
  • the Q value is:
  • the accuracy of Q is limited by the step value k.
  • the unit of measurement step size is reduced by a factor of two when the Q value is guaranteed.
  • the accuracy of the Q value is doubled, and the ability to identify foreign objects is enhanced.
  • the possible measurement accuracy is 1.
  • the obtained measurement accuracy is 0.5; the step length of the original measured Q value is changed from integer units to 0.5 units , As the step size unit becomes smaller, the measurement result is more accurate, and it can be more accurately judged whether there are foreign objects in the coil, thereby improving the accuracy of the measurement.
  • the first parameter may also include other parameters, so that the value of m is greater than 2, thereby obtaining a smaller measurement accuracy unit and a more accurate measurement result.
  • the output voltage of the LC series circuit is output through the full-bridge circuit, and the Q value is calculated by the number of crests, troughs, or the sum of crests and troughs, so as to realize the detection of foreign objects in the charging coil.
  • This embodiment provides another wireless charging circuit.
  • the structure of the wireless charging circuit is similar to that of the first embodiment. The difference is that in this embodiment, the full bridge circuit in the oscillation circuit 10 is replaced with a half bridge circuit, and the detection circuit Increase the voltage bias module.
  • the comparison module includes two or more comparators. Further, the two or more comparators are also called integrated voltage comparators.
  • the oscillation circuit 10 includes: an excitation voltage source Us, a half-bridge circuit, an LC series circuit, and the equivalent impedance R of the LC series circuit.
  • the equivalent resistance R is not shown in FIG. 7.
  • U 0 is the voltage amplitude of the variable frequency excitation voltage source Us.
  • the wireless charging circuit also includes a charging control resistor R0, which is used to suppress the oscillation of the circuit oscillation 10 when the LC series circuit is charged.
  • the half-bridge circuit includes a fifth switching tube Q5 and a sixth switching tube Q6, and Q5 and Q6 are connected in series, the phase midpoint of the half-bridge circuit is O3, and one end of the half-bridge circuit is connected to the charging control resistor R0 The other end is connected to the negative pole of the excitation voltage source Us.
  • the LC series circuit includes an inductor Lp and a resonant capacitor Cp, and the phase midpoint of the inductor Lp and the resonant capacitor Cp is M.
  • the equivalent impedance R is also included in the LC series circuit.
  • the phase midpoint of the LC series circuit M is connected to the detection circuit 20, and is used to output the resonance voltage signal generated by the damping oscillation to the detection circuit 20.
  • the resonance voltage signal is in turn the phase midpoint M of the LC series circuit.
  • the voltage of the ground is connected to the detection circuit 20, and is used to output the resonance voltage signal generated by the damping oscillation to the detection circuit 20.
  • the resonance voltage signal is in turn the phase midpoint M of the LC series circuit.
  • the voltage of the ground is the voltage of the ground.
  • the detection circuit 20 includes: a voltage bias module, a comparison module, and a processing module.
  • the voltage bias module is connected to the oscillating circuit, and is used to receive the resonant voltage signal output by the oscillating circuit, and transmit the resonant voltage signal to the comparison module after subjecting the resonant voltage signal to bias processing.
  • the comparison module is configured to receive and convert the resonant voltage signal output after the bias processing into a digital square wave signal, and then output it to the processing module.
  • the output biased resonance voltage is Uc+V ref 0
  • V ref 0 is the bias voltage
  • the output terminal of the comparison module is connected with the processing module. Further, the comparison module includes a first comparator (can be expressed as "Com1") and a second comparator (can be expressed as "Com2").
  • the Com1 includes an input terminal d1, an input terminal d2, and an output terminal h1;
  • the Com2 includes an input terminal g1, an input terminal g2, and an output terminal h2, and the phase midpoint M of the LC series circuit passes through the voltage offset
  • the set module is connected to the input terminal d2 of Com1 and the input terminal g1 of Com2, the input terminal d1 is connected to a first voltage source, the input terminal g2 is connected to a second voltage source, and the output of Com1
  • the terminal h1 is connected to the output terminal h2 of the Com2, and the connection point is P.
  • the first voltage source is used to provide a first reference voltage V ref 1 to Com1; the second voltage source is used to provide a second reference voltage V ref 2 to Com2.
  • the input terminals d1 and g1 are non-inverting input terminals +, and the input terminals d2 and g2 are inverting input terminals -.
  • the comparison module is used to determine whether the resonant voltage Uc+V ref 0 after the bias processing is located between the first reference voltage V ref 1 and the second reference voltage V ref 2 , if so, that is, V ref 2 ⁇ Uc+V ref 0 ⁇ V ref 1 , the output voltage is low level. Otherwise, the output voltage is high, and a square wave signal is generated when the output is high, forming a rising edge.
  • the comparison module sends the generated digital square wave signal to the processing module.
  • the oscillating circuit when the voltage Uc of the phase midpoint M of the LC series circuit to the ground reaches the amplitude voltage U 0 of the excitation voltage source Us, the oscillating circuit generates damped oscillation and generates a resonant voltage, and the resonant voltage passes
  • the resonant voltage after the bias processing of the voltage bias module is Uc+V ref 0
  • Uc is the resonant voltage generated by damped oscillation
  • V ref 0 is the bias voltage
  • the second preset condition is Uc+V ref 0 >V ref 1 , or Uc+V ref 0 ⁇ V ref 2 , where V ref 1 is the first reference voltage, and V ref 2 is the second reference voltage.
  • the processing module receives the digital square wave signal output from the comparison module, obtains the resonant voltage attenuation waveform of the damped oscillation according to the on and off of the switching tubes Q1 to Q4, and obtains the resonant voltage attenuation waveform that satisfies the second preset
  • the second parameter of the condition is set, the Q value is determined according to the second parameter, the foreign object is detected according to the quality factor Q, and the detection result is obtained.
  • the second parameter includes the sum of the number of crests and the number of troughs.
  • the method for the processing module to determine the Q value according to the second parameter includes:
  • the fifth switching tube Q5 is controlled to be turned on, and the sixth switching tube Q6 is turned off, forming a fifth loop: Us ⁇ Q5 ⁇ Lp ⁇ Cp ⁇ GND ⁇ Us. At this time, the excitation voltage source Us charges the LC series circuit.
  • the voltage bias module receives the resonant voltage signal output by the oscillation circuit, performs bias processing on the resonant voltage signal, and transmits the resonant voltage signal to the comparison module.
  • the comparison module receives and converts the biased resonance voltage signal into a digital square wave signal, and outputs it to the processing module.
  • the processing module receives the digital square wave signal, obtains the damped oscillation resonant voltage attenuation waveform according to the on and off of the switching tubes Q1 to Q4, and obtains the resonant voltage attenuation waveform that meets the second preset condition among the resonant voltage attenuation waveforms.
  • the second parameter is the sum of the number of crests and the number of troughs.
  • FIG. 9 it is a schematic diagram of the attenuation waveform of the resonant voltage Uc in an oscillating circuit, where V ref 0 is the bias voltage, V ref 1 is the first reference voltage, V ref 2 is the second reference voltage, U 0 + V ref 0 represents the amplitude voltage U 0 generated by the oscillating circuit after being processed by the bias voltage V ref 0.
  • Uc is the voltage at the midpoint M of the phase of the LC series circuit to ground, also called the resonance voltage.
  • the processing module determines the quality factor Q according to the second parameter (the sum of the number of crests and the number of troughs).
  • Uc is the resonance voltage output by the oscillation circuit
  • U 0 is the voltage amplitude of the excitation voltage source Us
  • ⁇ V is the voltage difference
  • V ref 0 is the bias voltage
  • V ref 1 is the first reference voltage
  • V ref 2 is the second reference voltage.
  • the quality factor Q is:
  • the calculation process of the above formula (14) can refer to the calculation process of the formula in the foregoing embodiment 1, and will not be repeated.
  • the processing module detects foreign objects according to the quality factor Q, and obtains a detection result.
  • the method for the processing module to determine whether there is a foreign object in the wireless charging coil according to the Q value is the same as the foregoing embodiment 1, which will not be repeated in this embodiment.
  • the wireless charging circuit provided in this embodiment detects the total number of peaks and troughs in a half cycle through the comparison module, and then calculates the Q value. Compared with using a voltage comparator to calculate the Q value, the measurement step size unit is reduced by one As the step size unit becomes smaller, the measurement result is more accurate, and it can be more accurately judged whether there are foreign objects in the coil, so that the detection accuracy of the Q value is doubled, and the ability to identify foreign objects is enhanced.
  • the positions of the inductance Lp and the resonant capacitor Cp in the LC series circuit are interchanged, and the damped oscillation voltage generated after the damped oscillation is sent Attenuation waveform, as shown in Figure 11.
  • the biased resonant voltage Uc+V ref 0 starts to oscillate and decay from -(U 0 -V ref 0 ). If Uc+V ref 0 > V ref 1 , the output is high level, a rising edge, the resonance voltage is offset from the first reference voltage V ref the intersection of the rising edge of the start time of 1, generates a square-wave signal 11 shown in solid line in FIG.
  • the processing module described in the foregoing embodiment may be a processing chip or a processing device. As shown in FIG. 12, a processor 1201 and a memory 1202 are included, and the processor 1201 is coupled with the memory 1202. In addition, the processing module may also include more or fewer components, or a combination of certain components, or a different component arrangement, which is not limited in this application.
  • the processor 1201 is the control center of the processing module, which uses various interfaces and lines to connect various parts of the entire device, runs or executes software programs or modules stored in the memory 1202, and calls data stored in the memory 1202. To perform the corresponding function.
  • the processor 1201 may be composed of an integrated circuit (IC), for example, may be composed of a single packaged IC, or may be composed of connecting multiple packaged ICs with the same function or different functions.
  • the processor 1201 may include a central processing unit (CPU) and the like.
  • the memory 1202 may include volatile memory (volatile memory), such as random access memory (random access memory, RAM), and may also include non-volatile memory (non-volatile memory), such as flash memory (flash memory), Hard disk drive (HDD) or solid-state drive (solid-state drive, SSD); the storage 1202 may also include a combination of the foregoing types of storage. Programs or codes or data can be stored in the memory.
  • volatile memory such as random access memory (random access memory, RAM)
  • non-volatile memory such as flash memory (flash memory), Hard disk drive (HDD) or solid-state drive (solid-state drive, SSD
  • HDD Hard disk drive
  • SSD solid-state drive
  • the present application also provides a computer storage medium, wherein the computer storage medium may store a program, and the program may include the method for determining the Q value provided in the present application, and the method shown in FIG. 4a, FIG. 4b, and FIG. 8 when the program is executed. Part or all of the steps in each embodiment.
  • the storage medium can be a magnetic disk, an optical disc, a read-only storage memory ROM, or a random storage memory RAM, etc.
  • all or part of it may be implemented by software, hardware, firmware or any combination thereof.
  • software it can be implemented in the form of a computer program product in whole or in part.
  • the computer program product includes one or more computer instructions, such as calculation instructions.
  • the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.
  • the computer instructions may be stored in a computer-readable storage medium.
  • the computer-readable storage medium may be any available medium that can be accessed by a computer or a storage device such as a server or a data center integrated with one or more available media.
  • the usable medium may be a magnetic medium, such as a floppy disk, a hard disk, a magnetic tape, an optical medium (such as a DVD), or a semiconductor medium, such as a solid-state hard disk, SSD, and the like.
  • the wireless charging device includes but is not limited to the circuit structure of the wireless charging circuit described in the first embodiment and the second embodiment.
  • the processing module in the wireless charging circuit may be a processing chip or a processing device as shown in FIG. 12 for executing the method for determining the Q value described in FIG. 4a, 4b or FIG. 8.
  • the method for determining the Q value in each embodiment of the present application can be applied to not only the transmitting end device, but also the receiving end device, for example, the device to be charged is a mobile phone.
  • the method for determining the Q value and the method for detecting foreign objects are not only applied to the detection of the wireless charging environment of mobile phones, but can also be applied to the detection of other charging environments, such as vehicle charging.
  • An embodiment of the present application also provides a wireless charging system, which includes a sending device and a receiving device.
  • the sending device is the wireless charging device in the foregoing embodiment
  • the receiving device is the device to be charged.
  • the wireless charging device includes the wireless charging circuit in the foregoing Embodiment 1 or Embodiment 2, which is used to implement the Q value determination method described in the embodiment of the present application and to detect foreign objects in the wireless charging coil.
  • the sending device is a wireless charging device
  • the receiving device is a device to be charged.
  • the receiving device also includes the wireless charging circuit in the foregoing Embodiment 1 or Embodiment 2, which is used to implement the method for determining the Q value described in the embodiment of the present application, and is equipped with a device for detecting foreign objects in the wireless charging coil. Function.
  • the receiving device includes: an oscillating circuit and a detection circuit connected in sequence.
  • the oscillating circuit includes a series-connected excitation voltage source, a full-bridge circuit, and an LC series circuit, wherein the excitation voltage source is used to provide a stable voltage for the LC series circuit.
  • the full bridge circuit includes a first bridge arm and a second bridge arm connected in parallel, the first bridge arm includes a first switching tube Q1 and a third switching tube Q3, and the second bridge arm includes a second switching tube Q2 and The fourth switch tube Q4.
  • the LC series circuit includes an inductance and a resonant capacitor connected in series, and one end of the LC series circuit is connected to the phase midpoint of the first bridge arm, and the other end is connected to the phase midpoint of the second bridge arm ;
  • the phase midpoint of the LC series circuit is connected to the detection circuit, and is used to output a damped oscillation resonant voltage signal to the detection circuit.
  • the detection circuit includes a comparison module and a processing module, and the comparison module is configured to receive the resonant voltage signal and convert the resonant voltage signal into a digital square wave signal.
  • the processing module is configured to receive the digital square wave signal, obtain the damped oscillation resonant voltage attenuation waveform according to the on and off of the switching tubes Q1 to Q4, and obtain the resonant voltage attenuation waveform that satisfies the first preset Set the first parameter of the condition, and determine the quality factor Q according to the first parameter; the first parameter includes the number of crests, the number of troughs, or the sum of the number of crests and the number of troughs.
  • the processing module is also used to detect foreign objects according to the quality factor Q, and obtain the detection result; wherein, if the quality factor Q is less than or equal to a first threshold, it is determined that there is a foreign object; if the quality factor Q If it is greater than the first threshold and less than or equal to the second threshold, it is determined that there may be a foreign object; if the quality factor Q is greater than the second threshold, it is determined that there is no foreign object.

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Abstract

公开了一种无线充电电路、无线充电方法、设备和系统，所述无线充电电路包括依次连接的振荡电路和检测电路；所述振荡电路包括串联的激励电压源、全桥电路和LC串联电路，LC串联电路包括串联的电感和谐振电容，且所述LC串联电路在发生阻尼振荡时，向检测电路输出阻尼振荡的谐振电压信号；所述检测电路包括比较模块和处理模块，比较模块用于接收谐振电压信号，并转换成数字方波信号；处理模块用于接收并获取谐振电压衰减波形中的满足第一预设条件的波峰数、波谷数、或波峰数和波谷数总和，以及根据这些参数确定品质因数Q，以及根据所述Q值对异物进行检测并得到检测结果，本方案实现了利用Q值对异物的检测，同时还提高了测量的精确度。

Description

一种无线充电电路、无线充电方法、设备和系统 技术领域
本申请属于无线充电技术领域，尤其是涉及一种无线充电电路、无线充电方法、设备和系统。
背景技术
无线充电是指利用电磁波感应原理进行充电的设备，原理类似于变压器。在发送端和接收端各有一个线圈，发送端线圈连接有线电源，并产生电磁信号。接收端线圈感应发送端的电磁信号，并转换成所需要的直流电，从而对接收端内的电池进行充电。
Qi标准是无线充电联盟(Wireless Power Consortium，WPC)推出的“无线充电”标准，它具备便捷性和通用性两大特征。随着无线充电技术的发展和普及，市场上涌现出许多无线充电产品，尤其是以基于WPC Qi标准的无线充电产品在市场拥有较大占有率。
在对接收端比如手机进行无线充电时，发射端需要对接收端进行实时检测和识别，当识别出接收端时开始在无线充电线圈中做能量传输。同时也需要对无线充电线圈中的充电环境做检测，如果线圈中有异物，比如银行卡、身份证或其它金属异物，则会使磁场产生涡流，使得这些异物消耗无线充电线圈中的能量，不仅降低充电效率，甚至还会引起火灾等事故，因此，异物检测成为保障无线充电过程安全性的首要问题。
发明内容
本申请提供一种无线充电电路及无线充电方法，该无线充电电路可以检测异物，并提高Q值检测的精确度。具体地，本申请公开了如下技术方案：
第一方面，本申请实施例提供了一种无线充电电路，该电路包括依次连接的振荡电路和检测电路；其中，所述振荡电路包括：串联的激励电压源Us、全桥电路和LC串联电路，其中，所述激励电压源Us用于为所述LC串联电路提供稳定电压。
进一步地，所述全桥电路包括并联的第一桥臂和第二桥臂，所述第一桥臂包括第一开关管Q1和第三开关管Q3，所述第二桥臂包括第二开关管Q2和第四开关管Q4；所述LC串联电路包括串联的电感Lp和谐振电容Cp，且所述LC串联电路的一端与所述第一桥臂的相位中点相连接，另一端与所述第二桥臂的相位中点相连接；所述LC串联电路的相位中心与所述检测电路相连接，用于向所述检测电路输出阻尼振荡的谐振电压信号。
所述检测电路包括比较模块和处理模块，所述比较模块用于接收所述振荡电路输出的所述谐振电压信号，并将所述谐振电压信号转换成数字方波信号；所述处理模块用于接收所述数字方波信号，根据开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取所述谐振电压衰减波形中的满足第一预设条件的第一参数，以及根据所述第一参数确定品质因数Q；所述第一参数包括波峰数、波谷数、或所述波峰数和所述波谷数总和。
此外，所述处理模块还用于根据所述品质因数Q对异物进行检测，并得到检测结果；其中，所述品质因数Q是表征所述振荡电路中所储能量与每周期损耗能量之比，Q值越大，该充电电路同周期的损耗越小，性能越佳。
本实施例提供的无线充电电路，通过设计包含第一桥臂和第二桥臂的全桥电路，从而通过控制全桥电路中开关管的导通和关断，实现振荡电路的充放电，并通过检测电路根据振荡电路输出的谐振电压波形确定满足预设条件的波峰数、波谷数、或波峰数和波谷数总和，以及计算出品质因数Q，从而实现了利用Q值对异物的检测。
其中，所述比较模块中包括比较器，进一步地，所述比较器为电压比较器，且所述电压比较器的一个输入端与参考电源相连接，用于获取参考电压；另一个输入端与所述振荡电路的输出端相连接，用于接收振荡电路产生的谐振电压，所述比较器的输出端与处理模块相连接。
此外，所述比较器还可以由其他电路替代，比如运算放大器等。所述比较模块中还可以包括其他辅助的控制电路，本实施例对此不予限制。
在第一方面中，所述第一预设条件为在每个振荡周期，所述阻尼振荡产生的谐振电压大于参考电压；其中，当所述LC串联电路的相位中点对地的电压达到所述激励电压源Us的幅值电压时，所述振荡电路发生阻尼振荡并产生所述谐振电压。
进一步地，在第一方面的一种具体的实施方式中，第一参数包括以下三种可能的实施方式：
第一种可能的实施方式，所述第一参数包括波峰数，所述满足第一预设条件的波峰数为，在所述第一桥臂的第一开光管Q1断开，第三开关管Q3导通，所述第二桥臂的第二开关管Q2由导通变成关断，第四开关管Q4由关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第一预设条件的波峰个数。
第二种可能的实施方式，所述第一参数包括波谷数，所述满足第一预设条件的波谷数为，在所述第二桥臂的第二开关管Q2关断，第四开关管Q4导通，所述第一桥臂的第一开关管Q1由导通变成关断，第三开关管Q3由关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第一预设条件的波谷个数。
第三种可能的实施方式，所述第一参数包括所述波峰数和所述波谷数总和，所述总和为满足第一预设条件的所述波峰个数与满足第一预设条件的所述波峰谷数之和。
结合第一方面，在第一方面的一种可能的实施方式中，所述处理模块具体用于，根据所述第一参数确定所述品质因数Q为：
Figure PCTCN2020125829-appb-000001
其中，m,n均为正整数，且m≥1，U1和U2为所述谐振电压衰减波形中的任一波峰电压或任一波谷电压。
进一步地，当所述第一参数为波峰数或者波谷数时，所述m＝1，所述品质因数Q为：
Figure PCTCN2020125829-appb-000002
其中，n为所述波峰数或者所述波谷数。
当所述第一参数为波峰数和波谷数的总和时，所述m＝2，所述品质因数Q为：
Figure PCTCN2020125829-appb-000003
其中，n为所述波峰数和所述波谷数总和。
本实施例提供的方法，在保证Q值一定的情况下，测量的步长单位由m来确定，m值越大，步长单位越小，测量精度越高。当第一参数为波峰数和波谷数总和时，m值为2，相比于单独使用波峰数或波谷数来确定Q值而言，测量步长单位缩小一倍，从而使得Q值的精度提升一倍，识别异物的能力增强。比如控制全桥电路中的4个开关管的导通和关断使得原来测量的Q值的步长从整数单位变更到0.5个单位，由于步长单位变小，所以测量的结果更精确，更能够准确地判断出线圈中是否存在异物，从而提高到了测量的准确度。
在上述Q值得计算公式中，
Figure PCTCN2020125829-appb-000004
当Q值一定时，n与m成正比，n与1/m成反比。
此外，
Figure PCTCN2020125829-appb-000005
振荡波形某一波峰或波谷电压U1所对应的时刻为t1，振荡波形某一波峰或波谷电压U2所对应的时刻为t2。其中，t1和t2可以包括以下4种情况：
t1为振荡波形的一个波峰时刻，t2为振荡波形的另一个波峰时刻；
或者，t1为振荡波形的一个波峰时刻，t2为振荡波形的一个波谷时刻；
或者，t1为振荡波形的一个波谷时刻，t2为振荡波形的另一个波峰时刻；
或者，t1为振荡波形的一个波谷时刻，t2为振荡波形的另一个波谷时刻。
其中，m取值越大，步长单位越小，测量精度越高，测量结果更准确。
第二方面，本申请实施例还提供了另一种无线充电电路，包括：依次连接的振荡电路和检测电路；其中，所述振荡电路包括：串联的激励电压源Us、半桥电路和LC串联电路，其中，所述激励电压源Us用于为所述LC串联电路提供稳定电压。
进一步地，所述半桥电路包括串联的第五开关管Q5和第六开关管Q6；所述LC串联电路包括串联的电感Lp和谐振电容Cp，且所述LC串联电路的一端与所述半桥电路的相位中点相连接，另一端接地；所述LC串联电路的相位中心与所述检测电路相连接，用于向所述检测电路输出阻尼振荡的谐振电压信号。
所述检测电路包括：电压偏置模块、比较模块和处理模块，所述电压偏置模块与所述振荡电路连接，用于接收所述振荡电路输出的所述谐振电压信号，并将所述谐振电压信号进行偏置处理后传输给所述比较模块，所述比较模块接收并将所述偏置的谐振电压信号转换成数字方波信号，输出给所述处理模块；所述处理模块用于接收所述数字方波信号，根据开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取所述谐振电压衰减波形中的满足第二预设条件的第二参数，根据所述第二参数确定品质因数Q，所述第二参数包括波峰数和波谷数总和。所述处理模块还用于根据所述品质因数Q对异物进行检测，并得到检测结果；其中，所述品质因数Q是表征所述振荡电路中所储能量与每周期损耗能量之比。
本方面，在振荡电路设计中包含半桥电路，并通过控制该半桥电路中的第五开关管Q5和第六开关管Q6的导通和关断，从而可以产生半周期的振荡电路，以及利用比较模块对振荡电路输出的谐振电压进行处理，得到第二参数和振荡频率，并计算出Q值，从而实现对无线充电线圈中异物的检测。
此外，本电路还可以测量并获得半周期的波峰数和波谷数总和，进而计算出Q值，相 比于采用一个电压比较器来计算Q值来说，测量的步长单位缩小一倍，由于步长单位变小，所以测量的结果更精确，更能够准确地判断出线圈中是否存在异物，从而使得Q值的检测精度提升一倍，增强了识别异物的能力。
其中，所述第二预设条件为Uc+V ref 0＞V ref 1，或者Uc+V ref 0＜V ref 2，其中，Uc为阻尼振荡产生的谐振电压，V ref 0为偏置电压，Uc+V ref 0为经过所述电压偏置模块偏置处理后的谐振电压，V ref 1为第一参考电压，V ref 2为第二参考电压；并且，当所述LC串联电路的相位中点对地的电压达到所述激励电压源Us的幅值电压时，所述振荡电路发生阻尼振荡并产生所述谐振电压。
结合第二方面，在第二方面的一种可能的实施方式中，所述波峰数和波谷数的总和为，在所述第五开关管Q5由导通变成关断，所述第六开关管Q6关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第二预设条件的所述波峰数和波谷数总和。
其中，对所述开关管Q5和Q6的控制可以由与开关管Q5和Q6相连接的控制电路来执行，例如该开关管Q5和Q6均为二极管、MOSFET管或IGBT等，且控制电路与每个开关管的栅极相连接，用于驱动开关管Q5和Q6导通或关断。
结合第二方面，在第二方面的一种可能的实施方式中，所述比较模块的输入端与所述电压偏置模块的输出端相连接，输出端与所述处理模块相连接。
其中，所述比较模块中包括第一比较器和第二比较器，具体的，所述第一比较器和所述第二比较器均包括第一输入端、第二输入端和输出端；所述第一比较器的第一输入端与第一电压源相连接，用于获取所述第一电压源提供的第一参考电压；所述第一比较器的第二输入端与所述第二比较器的第一输入端相连接，作为所述比较电路的输入端；所述第二比较器的第二输入端与第二电压源相连接，用于获取第二电压源提供的第二参考电压；所述第一比较器的输出端与所述第二比较器的输出端相连接，作为所述比较模块的输出端。
可选的，所述第一参考电压和第二参考电压可以为正值，也可以为负值。
结合第二方面，在第二方面的另一种可能的实施方式中，所述处理模块具体用于，根据所述第二参数确定所述品质因数Q为：
Figure PCTCN2020125829-appb-000006
其中，n，m均为正整数，且m≥1，U 0为所述激励电压源Us的电压幅值，ΔV为偏置电压与参考电压之间的电压差，所述参考电压为第一参考电压或第二参考电压。
进一步地，当m＝2时，所述品质因数Q为：
Figure PCTCN2020125829-appb-000007
其中，n为所述波峰数和所述波谷数的总和。
在每半个周期内，如果Uc+V ref 0＞ΔV，ΔV＝V ref 1-V ref 0，或者，Uc+V ref 0＜ΔV，ΔV＝V ref 0-V ref 2，则满足第二预设条件，输出一高电平，产生一个上升沿；Uc为所述振荡电路输出的谐振电压，ΔV为电压差，且ΔV＝V ref 1-V ref 0＝V ref 0-V ref 2，V ref 0为偏置电压，V ref 1 为第一参考电压，V ref 2为第二参考电压。
如果V ref 2≤Uc+V ref 0≤V ref 1，则不满足第二预设条件，不产生高电平，输出低电平信号。
第三方面，本申请实施例还提供了一种无线充电方法，所述方法应用于一种无线充电电路，该电路结构与前述第一方面所述的无线充电电路的结构相同。具体地，所述无线充电电路包括依次连接的振荡电路和检测电路。
其中，所述振荡电路包括：串联的激励电压源Us、全桥电路和LC串联电路，其中，所述激励电压源Us用于为所述LC串联电路提供稳定电压；所述全桥电路包括并联的第一桥臂和第二桥臂，所述第一桥臂包括第一开关管Q1和第三开关管Q3，所述第二桥臂包括第二开关管Q2和第四开关管Q4；所述LC串联电路包括串联的电感Lp和谐振电容Cp，且所述LC串联电路的一端与所述第一桥臂的相位中点相连接，另一端与所述第二桥臂的相位中点相连接；所述LC串联电路的相位中点与所述检测电路相连接，用于向所述检测电路输出阻尼振荡的谐振电压信号；所述检测电路包括比较模块和处理模块，所述比较模块用于接收所述谐振电压信号，并将所述谐振电压信号转换成数字方波信号。
所述方法包括：
所述处理模块接收所述数字方波信号，所述数字方波信号由所述谐振电压信号转换生成。
所述处理模块根据所述开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取根据谐振电压衰减波形中的满足第一预设条件的第一参数；所述第一参数包括波峰数、波谷数、或所述波峰数和所述波谷数总和。
所述处理模块根据所述第一参数确定品质因数Q。
所述处理模块根据所述品质因数Q对异物进行检测，并得到检测结果。
其中，所述第一预设条件为在每个振荡周期，所述阻尼振荡产生的谐振电压大于参考电压；当所述LC串联电路的相位中点对地的电压达到所述激励电压源Us的幅值电压时，所述振荡电路发生阻尼振荡并产生所述谐振电压。
结合第三方面，在第三方面的一种可能的实施方式中，
所述第一参数包括波峰数，所述满足第一预设条件的波峰数为，在所述第一桥臂的第一开光管Q1断开，第三开关管Q3导通，所述第二桥臂的第二开关管Q2由导通变成关断，第四开关管Q4由关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第一预设条件的波峰个数。
所述第一参数包括波谷数，所述满足第一预设条件的波谷数为，在所述第二桥臂的第二开关管Q2关断，第四开关管Q4导通，所述第一桥臂的第一开关管Q1由导通变成关断，第三开关管Q3由关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第一预设条件的波谷个数。
所述第一参数包括所述波峰数和所述波谷数总和，所述总和为所述满足第一预设条件的所述波峰个数与所述满足第一预设条件的所述波峰谷数之和。
结合第三方面，在第三方面的另一种可能的实施方式中，所述处理模块根据所述第一参数确定品质因数Q，包括：所述处理模块根据所述第一参数确定所述品质因数Q为：
Figure PCTCN2020125829-appb-000008
其中，n，m均为正整数，且m≥1，U1和U2为所述谐振电压衰减波形中的任一波峰电压或任一波谷电压。
进一步地，当m＝2时，所述品质因数Q为：
Figure PCTCN2020125829-appb-000009
其中，n为所述波峰数和所述波谷数总和。
此外，结合第三方面，在第三方面的又一种可能的实施方式中，所述对异物进行检测包括：如果品质因数Q小于等于第一阈值，则确定无线充电线圈中存在异物；如果品质因数Q大于第一阈值，且小于等于第二阈值，则确定在无线充电线圈中可能存在异物，需要做进一步地检查；如果品质因数Q大于第二阈值，则确定无线充电线圈中无异物。所述第一阈值和第二阈值可以自行设定。
第四方面，本申请实施例还提供了另一种无线充电方法，所述方法应用于一种无线充电电路，该电路结构与前述第二方面所述的无线充电电路的结构相同。所述无线充电电路包括依次连接的振荡电路和检测电路。
其中，所述振荡电路包括：串联的激励电压源Us、半桥电路和LC串联电路，其中，所述激励电压源Us用于为所述LC串联电路提供稳定电压；所述半桥电路包括串联的第五开关管Q5和第六开关管Q6；所述LC串联电路包括串联的电感Lp和谐振电容Cp，且所述LC串联电路的一端与所述半桥电路的相位中点相连接，另一端接地；所述LC串联电路的相位中点与所述检测电路相连接，用于向所述检测电路输出阻尼振荡的谐振电压信号；所述检测电路包括：电压偏置模块、比较模块和处理模块，所述电压偏置模块接收所述谐振电压信号，并将所述谐振电压信号进行偏置处理后传输给所述比较模块；所述比较模块接收并将所述偏置的谐振电压信号转换成数字方波信号，再输出给所述处理模块。
所述方法包括：
所述处理模块接收所述数字方波信号。
所述处理模块根据开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取所述谐振电压衰减波形中的满足第二预设条件的第二参数，所述第二参数包括波峰数和波谷数总和，所述处理模块根据所述第二参数确定品质因数Q。
所述处理模块还用于根据所述品质因数Q对异物进行检测，并得到检测结果。
进一步地，所述第二预设条件为Uc+V ref 0＞V ref 1，或者Uc+V ref 0＜V ref 2，其中，V ref 1为第一参考电压，V ref 2为第二参考电压，V ref 0为偏置电压，Uc为阻尼振荡产生的谐振电压，Uc+V ref 0为经过所述电压偏置模块偏置处理后的谐振电。
当所述LC串联电路的相位中点对地的电压达到所述激励电压源Us的幅值电压时，所述振荡电路发生阻尼振荡并产生所述谐振电压。
结合第四方面，在第四方面的一种可能的实施方式中，所述波峰数和波谷数的总和为，在所述第五开关管Q5由导通变成关断，所述第六开关管Q6关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第二预设条件的所述波峰数和波谷数的总和。
结合第四方面，在第四方面的另一种可能的实施方式中，所述处理模块根据所述第二参数确定品质因数Q，包括：所述处理模块根据所述第二参数确定所述品质因数Q为：
Figure PCTCN2020125829-appb-000010
其中，n，m均为正整数，且m≥1，U 0激励电压源Us的电压幅值，ΔV为偏置电压与参考电压之间的电压差，所述参考电压为第一参考电压或第二参考电压。
进一步地，当m＝2时，所述品质因数Q为：
Figure PCTCN2020125829-appb-000011
其中，n为所述波峰数和所述波谷数的总和。
第五方面，本申请实施例还提供了一种处理装置，所述处理装置包括：处理器和存储器，且所述处理器与存储器耦合。进一步地，所述处理器用于运行或执行存储在所述存储器内的计算机程序指令，以及调用所述存储器内的数据，以执行前述第三方面或第四方面各种实施方式所述的方法，并根据所述Q值检测出充电线圈中是否存在异物。
其中，可选的，所述处理器为处理芯片或处理模块。
可选的，所述处理器为随机存取内存RAM，或非易失性存储器，比如闪存、硬盘等。
第六方面，本申请实施例还提供了一种设备，所述设备为发送设备或者接收设备，所述发送设备或者接收设备包含前述第一方面以及第一方面各种实现方式中的无线充电电路，并通过该无线充电电路实现前述第二方面以及第二方面各种实现方式所述的方法，并对异物进行检测。
具体地，所述检测过程包括：判断所述品质因数Q值与第一阈值和第二阈值之间的关系。
如果品质因数Q小于等于第一阈值，则确定无线充电线圈中存在异物。
如果品质因数Q大于第一阈值，且小于等于第二阈值，则确定在无线充电线圈中可能存在异物，需要做进一步地检查。
如果品质因数Q大于第二阈值，则确定无线充电线圈中无异物。
此外，还可以通过其他方法策略来检测是否存在异物。
第七方面，本申请实施例还提供了一种无线充电系统，所述系统包括发送设备和接收设备，所述发送设备包括前述第一方面或第二方面所述的无线充电电路，所述接收设备为待充电设备。
可选的，所述接收设备也包括前述第一方面或第二方面所述的无线充电电路，并实现异物检测功能。
第八方面，本申请实施例还提供了一种计算机可读存储介质，所述存储介质中存储有指令，当所述指令在计算机或处理器上运行时，用于执行前述第三方面或第四方面中各种实现方式中的方法。
进一步地，还提供了一种计算机程序产品，所述计算机程序产品包括计算机指令，当所述指令被计算机或处理器执行时，可实现前述第三方面或第四方面各种实现方式中的方法。
附图说明
图1为本申请实施例提供的一种无线充电电路的结构示意图；
图2为本申请实施例提供的另一种无线充电电路的结构示意图；
图3为本申请实施例提供的一种全桥电路的结构示意图；
图4a为本申请实施例提供的一种确定Q值方法的流程图；
图4b为本申请实施例提供的一种确定波峰数的方法流程图；
图5a为本申请实施例提供的一种谐振电路的等效电路图；
图5b为本申请实施例提供的一种振荡电路产生的谐振电压衰减波形的示意图；
图6a为本申请实施例提供的另一种谐振电路的等效电路图；
图6b为本申请实施例提供的另一种振荡电路产生的谐振电压衰减波形的示意图；
图7为本申请实施例提供的另一种无线充电电路的结构示意图；
图8为本申请实施例提供的另一种确定Q值方法的流程图；
图9为本申请实施例提供的又一种振荡电路产生的谐振电压衰减波形的示意图；
图10为本申请实施例提供的又一种无线充电电路的结构示意图；
图11为本申请实施例提供的又一种振荡电路产生的谐振电压衰减波形的示意图；
图12为本申请实施例提供的一种处理模块的结构示意图。
具体实施方式
为了使本技术领域的人员更好地理解本申请实施例中的技术方案，并使本申请实施例的上述目的、特征和优点能够更加明显易懂，下面结合附图对本申请实施例中的技术方案作进一步详细的说明。
首先，对本申请实施例涉及的技术场景进行说明。
本申请的技术方案应用于无线充电技术场景。该场景包括无线充电设备和待充电设备。其中，无线充电设备用于对具有无线充电功能的待充电设备进行充电。例如，该无线充电设备可以是无线充电式移动电源、无线充电板、无线充电器等。待充电设备包括手机、平板、笔记本电脑、车载装置以及数码相机等具有内置可充电电池的电子设备。
其中，所述无线充电设备又可称为发送设备，所述待充电设备又可称为接收设备。
可选的，在一种无线充电设备中，包括壳体、无线充电线圈和承载装置等。具体地，所述壳体表面设置有用于承载待充电设备的充电面，因此，可以将待充电设备放置于壳体的充电面上。此外，本申请实施例中，壳体内还设置有电池以及电路板，电池用于存储电能并向外输出电能。电路板上设置有无线充电电路，该无线充电电路与无线充电线圈之间电连接，用于对无线充电设备充放电过程进行控制，以及对整个无线充电设备的工作状态进行控制。
无线充电线圈设置在壳体内，用于将电池的电能转换为磁能，进行传输发射。承载装置设置在壳体内，用于承载并固定无线充电线圈，以及对无线充电线圈起保护作用。
本申请实施例主要解决，在利用电磁波感应原理对待充电设备进行充电时，如何检测充电环境是否良好的技术问题，即检测无线充电线圈是否存在异物，影响充电质量。
为解决该技术问题，本申请实施例提供了一种确定品质因数Q(或称“Q值”)的方法，其中，品质因数是表示一个储能器件(如电感、电容等)、谐振电路中所储能量与每周期损耗能量之比。串联谐振回路中电抗元件的Q值等于它的电抗与其等效串联电阻的比值，并且元件的Q值越大，用该元件组成的电路或网络损耗越小，性能越佳，所以品质因数Q 可用于评价回路损耗的大小。一般来说，Q值的范围在几十到几百范围内。本申请实施例可以通过阻尼振荡法来得到Q值。具体地，通过设计一种无线充电电路来获取LC串联电路发生阻尼振荡时，产生的谐振电压衰减波形来确定Q值。
下面的实施例对无线充电设备中的一种无线充电电路进行详细说明。
如图1所示，为本申请实施例提供的一种无线充电电路的结构示意图，该电路包括振荡电路10和检测电路20，其中，所述振荡电路10包括：依次连接的电源1001、检测控制电路1002、LC串联电路1003；所述检测电路20包括比较模块2001和处理模块2002。
其中，所述电源1001可以是激励电压源Us，用于为振荡电路10提供电压。检测控制电路1002与电源1001和LC串联电路1003串联，用于检测电压以及控制为LC串联电路1003充放电。检测控制电路1002中包括至少一个开光管，所述开光管包括开关、二极管、金属-氧化物半导体场效应晶体管(MOSFET管)、绝缘栅双极型晶体管(Insulated Gate Bipolar Transistor，IGBT)等，或者，所述开关管还可以包括其他材料组成。所述LC串联电路1003在阻尼振荡过程中输出谐振电压信号，并且该谐振电压信号输出至比较模块2001和处理模块2002，由比较模块2001和处理模块2002对该谐振电压信号进行采用处理，并计算出Q值，以及利用Q值实现对异物的检测。
进一步地，该无线充电电路中的各个电路组件可以包括以下具体的实施方式。
实施例一
如图2所示，为本实施例提供另一种无线充电电路的结构示意图，该电路包括：振荡电路10和检测电路20，且振荡电路10与检测电路20相连接，进一步地，振荡电路10包括：激励电压源Us、全桥电路、LC串联电路以及所述LC串联电路的等效阻抗R，该等效阻抗R在图2中未示出。其中，该激励电压源Us的电压幅值为U 0。此外，该无线充电电路中还包括充电控制电阻R0，该电阻R0用于在对LC串联电路充电时，抑制电路振荡10发生振荡。
进一步地，如图3所示，所述全桥电路包括：并联的第一桥臂11和第二桥臂12，所述第一桥臂11包括第一开关管Q1和第三开关管Q3，所述第二桥臂12包括第二开关管Q2和第四开关管Q4；且Q1与Q3串联，Q2与Q4串联，第一桥臂11的相位中点为O1，第二桥臂12的相位中点为O2。其中，每个桥臂的相位中点的两端电势相等。所述全桥电路的一端通过充电控制电阻R0与激励电压源Us的正极相连，另一端与激励电压源Us的负极相连。所述激励电压源Us用于为LC串联电路提供稳定电压。
应理解，上述图1所示的检测控制电路1002的功能由本实施例中的全桥电路来实现，该全桥电路可用于控制激励电压源Us为LC串联电路充放电。
参见图2，所述LC串联电路包括串联的电感Lp和谐振电容Cp，所述电感Lp和谐振电容Cp串联，且电感Lp和谐振电容Cp的相位中点为M。此外，在该LC串联电路中还包括等效阻抗R，该等效阻抗在图2中未示出。所述LC串联电路与全桥电路相连接，具体地，全桥电路的第一桥臂的相位中点O1与所述LC串联电路的一端相连接，所述全桥电路的第二桥臂的相位中点O2与所述LC串联电路的另一端相连接。所述LC串联电路的相位中点M对接地(GND)的电压为Uc，且所述相位中点M输出的引脚与检测电路20相连接。
所述检测电路20包括：比较模块和处理模块。
其中，所述比较模块中包括一个比较器，该比较器可用“Com”表示。进一步地，该 比较器Com为一种电压比较器。本实施例中的比较模块以比较器Com为例进行说明。
所述比较器包括第一输入端(又称输入端1)、第二输入端(又称输入端2)和输出端。其中，所述输入端1为同相输入端+，所述输入端2为反相输入端-。并且，输入端1与LC串联电路相位中点M输出的引脚相连接，输入端2与参考电源相连接，所述参考电源提供参考电压；比较器的输出端与所述处理模块相连接。
其中，所述参考电压可以表示为“Vref”，且参考电压值可以是正值，也可以是负值。
所述比较器，用于获取振荡电路发生阻尼振荡时输出的谐振电压信号，并将该谐振电压信号(即LC串联电路的相位中点M对地的电压Uc)转化为数字方波信号，并传输给处理模块。
所述处理模块与比较器的输出端相连接，用于接收比较器输出的数字方波信号，根据开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取所述谐振电压衰减波形中的满足第一预设条件的第一参数，根据所述第一参数确定品质因数Q，以及根据所述品质因数Q对异物进行检测，并得到检测结果。所述品质因数Q是表征所述振荡电路中所储能量与每周期损耗能量之比，Q值越大，损耗越小，充电效果越佳。
其中，所述第一预设条件为在每个振荡周期，所述阻尼振荡产生的谐振电压大于参考电压。当所述LC串联电路的相位中点M对地的电压达到所述激励电压源Us的幅值电压时，所述振荡电路发生阻尼振荡并产生所述谐振电压。
另外，所述第一参数包括波峰数、波谷数、或所述波峰数和所述波谷数总和。此外，还可以包括其他参数。具体地，包括以下三种实施方式：
第一种可能的实施方式，所述第一参数为波峰数。如图4a所示，所述方法包括：
401：处理模块获取满足所述第一预设条件的波峰数。其中，所述波峰数用“n1”表示。
在全桥电路中，第一桥臂的Q1和Q3两个开关管中同时只能有一个开关管导通，另一个开关管关断。同理地，在第二桥臂，Q2和Q4两个开关管中同时也只能有一个开关管导通，另一个开关管关断。进一步地，如图4b所示，步骤401包括：
4011：控制全桥电路中的开关管Q1～Q4使得激励电压源Us对所述LC串联电路充电。
具体地，控制第一桥臂中的第一开关管Q1关断，第三开关管Q3导通；同时，控制第二桥臂中的第二开关管Q2导通，第四开关管Q4关断，此时所述振荡电路形成第一回路：Us→Q2→Cp→Lp→Q3→接地GND→Us，激励电压源Us对电容Cp充电。
4012：当所述LC串联电路的相位中点M对地的电压达到激励电压源Us的幅值电压U 0时，控制全桥电路中的开关管Q1～Q4使得所述LC串联电路放电，振荡电路开始阻尼振荡。
具体地，当所述LC串联电路的相位中点M对地的电压Uc为所述幅值电压U 0时，控制第二桥臂的第二开关管Q2关断，第四开关管Q4导通，并保持第一桥臂中的第一开关管Q1和第三开关管Q3的状态不变，此时所述振荡电路形成第二回路是：GND→Q3→Lp→Cp→Q4→GND，LC串联电路的电容Cp放电。
等效电路如图5a所示，当控制所述Q3导通，Q4导通、Q2关断时，相当于将等效电路中的开关K从触头a拨至触头b(t＞0)，形成所述第二回路。所述LC串联电路输出谐振电压Uc给所述比较器。所述谐振电压从幅值电压U 0开始衰减。
其中，步骤4011和步骤4012可以由与开关管Q1至Q4相连接的控制电路来执行，例 如该开关管Q1至Q4均为MOSFET管，且控制电路与每个MOSFET管的栅极相连接，用于驱动开关管Q1至Q4导通或关断。
4013：比较器获取振荡电路输出的谐振电压信号Uc，将该谐振电压信号Uc转化为数字方波信号，并传输给处理模块。
其中，比较器用于比较振荡电路在每个振荡周期输出的谐振电压信号与参考电压的大小。进一步地，判断在每个振荡周期，所述阻尼振荡产生的谐振电压Uc是否大于参考电压Vref，如果是，则满足所述第一预设条件；否则，不满足。
如图5b所示的一种振荡电路产生的谐振电压衰减波形的示意图。激励电压源Us产生一阶阶跃激励信号e(t)，其振荡电路输出的谐振电压衰减波形经比较器后，在一定时间内，输出的谐振电压Uc逐渐衰减，图5b中波浪线表示谐振电压衰减曲线，方波线表示转换后的数字方波信号。所述振荡周期的频率为f1，在每个振荡周期(1/f1)内，如果阻尼振荡产生的输出谐振电压Uc＞Vref，所述Vref为一直流电平，本实施例设该直流电平为一正电平,则产生一个方波信号，并出现一个方波的上升沿，所述上升沿的起始时刻为谐振电压衰减曲线与参考电压的交点。如果Uc≤Vref，则不会产生方波信号，阻尼振荡趋于结束。在所述谐振电压衰减曲线中，满足所述第一预设条件的波峰数与方波波形中的上升沿个数相同。
4014：处理模块接收来自比较器的数字方波信号，根据开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取所述谐振电压衰减波形中满足第一预设条件的波峰数n1。
具体地，振荡电路从做阻尼振荡开始到振荡结束的过程中，LC串联电路输出的谐振电压Uc从幅值电压U 0逐渐减小到0，处理模块根据比较器输出的数字方波信号，确定波峰数n1，所述n1与方波波形中的上升沿的个数相同。在图5b所示的示例中，满足所述第一预设条件的波峰数为5个，即n1＝5。
第二种可能的实施方式，所述第一参数为波谷数。如图4a所示，所述方法包括：
402：处理模块获取满足所述第一预设条件的波谷数。所述波谷数用“n2”表示。
具体地，获取波谷数n2的方法与步骤401中获取波峰数n1的方法相似。具体包括：
首先，控制全桥电路中的开关管Q1～Q4使得激励电压源Us对所述LC串联电路充电。
具体地，控制第一桥臂中的第一开关管Q1导通，第三开关管Q3关断；同时，控制第二桥臂中的第二开关管Q2关断，第四开关管Q4导通，此时所述振荡电路形成第三回路：Us→Q1→Lp→Cp→Q4→GND→Us，此时激励电压源Us对电容Cp充电。
其次，当所述LC串联电路的相位中点对地的电压Uc达到激励电压源Us的幅值电压U 0时，控制全桥电路中的开关管Q1～Q4使得所述LC串联电路放电，振荡电路开始阻尼振荡。具体地，当所述谐振电压信号Uc为所述幅值电压U 0时，控制第一桥臂中的第三开关管Q3导通，第一开关管Q1关断，并保持所述第二桥臂中的第二开关管Q2关断，第四开关管Q4导通状态不变，此时所述振荡电路形成第四回路是：GND→Q3→Lp→Cp→Q4→GND，LC串联电路的电容Cp放电。
等效电路如图6a所示，当控制所述Q3导通，Q4导通、Q1关断、Q2关断时，相当于将等效电路中的开关K从触头a拨至触头b(t＞0)，形成第四回路。所述LC串联电路输出谐振电压信号Uc给比较器。
再次，比较器获取振荡电路输出的谐振电压信号Uc，将该谐振电压的电压信号Uc转化为数字方波信号，并传输给处理模块。
其中，比较器用于比较振荡电路在每个振荡周期输出的电压信号Uc与参考电压Vref的大小。如图6b所示，为振荡电路输出的谐振电压衰减波形的示意图。激励电压源Us产生一阶阶跃激励信号e(t)，其LC振荡电路的衰减振荡信号经电压比较器后，在一定时间内，输出的电压逐渐衰减，图6b中波浪线表示谐振电压的衰减波形曲线，该波形与图5b所示的波形关于横轴对称，方波线表示转换后的数字方波信号。振荡周期所对应的频率为f2，在每个振荡周期(1/f2)内，如果阻尼振荡产生的谐振电压Uc＞Vref，则产生一个方波信号，并出现一个方波的上升沿。如果Uc≤Vref，则不会产生方波信号，阻尼振荡趋于结束。其中，图6b所示的波形为中满足所述第一预设条件的波峰数，相当于图5b所示的衰减波形的波谷数，该波谷数与产生方波波形中的上升沿的个数相同。
再次，处理模块接收来自比较器的数字方波信号，并根据该数字方波信号确定所述波谷数n2。在图6b所示的示例中，满足所述第一预设条件的波谷数为6个，即n2＝6，对应的振荡频率为f2。
第三种可能的实施方式，所述第一参数为波峰数与波谷数的总和。如图4a所示，所述方法包括：
403：处理模块获取所述波峰数与波谷数的总和。该总和(或称总数)可以用n表示。
所述波峰数与波谷数总和n＝n1+n2，且振荡频率f≈f1≈f2。更进一步地，获取所述波峰数n1过程参见前述步骤401的详细描述；获取所述波谷数n2过程参见前述步骤402的详细描述，此处不再赘述。
应理解，如果第一参数中还包括其他参数，还可以包括获取这些参数的过程。
404：处理模块根据所述波峰数与波谷数的总和n(第一参数)确定品质因数Q。
具体地，如图6a所示，在K动作前，即t≤0时刻，LC串联电路的输入源为激励电压源Us，其输出直流电压幅值为U 0,电容Cp充满时的电压为U 0。
而当K动作后，t＞0，LC输入源的电压值由U 0下跳到0，就会引电容Cp电压u(t)开始衰减自由振荡，其自由振荡公式为：
Figure PCTCN2020125829-appb-000012
解上述二阶微分方程(1)可得：
当
Figure PCTCN2020125829-appb-000013
即Q＞1/2时根据初始条件：
Figure PCTCN2020125829-appb-000014
解得
Figure PCTCN2020125829-appb-000015
其中，定义为谐振电路的品质因数Q(称Q值)，即
Figure PCTCN2020125829-appb-000016
谐振发生条件为
Figure PCTCN2020125829-appb-000017
其中，
Figure PCTCN2020125829-appb-000018
ω 0为角频率，f 0为频率。
Figure PCTCN2020125829-appb-000019
当等效阻抗R足够小，即Q足够大时，ω≈ω 0即式(3)中的
Figure PCTCN2020125829-appb-000020
因此得到
Figure PCTCN2020125829-appb-000021
令
Figure PCTCN2020125829-appb-000022
即
Figure PCTCN2020125829-appb-000023
则代入式(7)中，可得，
Figure PCTCN2020125829-appb-000024
当n为自然数，即n≥0,上式(8)为
Figure PCTCN2020125829-appb-000025
当n为奇数时，u(t)为负峰值，当n为偶数时，u(t)为正峰值。取任意两个峰值时刻t1和t2所对应的波峰或波谷电压为U1和U2，t1和t2为谐振电压衰减波形中任意两个波峰或波谷的时刻。
例如，t1为振荡波形的一个波峰时刻，t2为振荡波形的另一个波峰时刻；或者，t1为振荡波形的一个波峰时刻，t2为振荡波形的一个波谷时刻；或者，t1为振荡波形的一个波谷时刻，t2为振荡波形的另一个波峰时刻；或者，t1为振荡波形的一个波谷时刻，t2为振荡波形的另一个波谷时刻。
则
Figure PCTCN2020125829-appb-000026
因此可得，
Figure PCTCN2020125829-appb-000027
对公式(10)两边取对数可得，
Figure PCTCN2020125829-appb-000028
其中，m、n均为正整数，且m≥1，
Figure PCTCN2020125829-appb-000029
Q为品质因数，振荡波形某一波峰或波谷的电压U1所对应的时刻为t1，某一波峰或波谷的电压U2所对应的时刻为t2，如果U1或U2为波谷电压，则为负值；如果U1或U2为波峰电压，则为正值。并且，当Q值一定时，n与m成正比，n与1/m成反比。
405：处理模块根据所述品质因数Q对异物进行检测，并得到检测结果。
具体的，一种检测方法是，设两个阈值，分别是第一阈值、第二阈值，并且第一阈值小于第二阈值。根据上述步骤获得的Q值在满足以下条件时，得到检测结果。
如果品质因数Q小于等于第一阈值，则确定无线充电线圈中存在异物。
如果品质因数Q大于第一阈值，且小于等于第二阈值，则确定在无线充电线圈中可能存在异物，需要做进一步地检查。
如果品质因数Q大于第二阈值，则确定无线充电线圈中无异物。
进一步地，在上述第一参数的三种可能实施方式中，如果第一参数包括波峰数n1或波谷数n2，即n＝n1或n＝n2，则m＝1，根据上述公式(11)可得，所述Q值为：
Figure PCTCN2020125829-appb-000030
或者，
Figure PCTCN2020125829-appb-000031
如果第一参数包括所述波峰数与波谷数的总和，即n＝n1+n2，则m＝2，根据上述公式(11)可得，所述Q值为：
Figure PCTCN2020125829-appb-000032
此外，由式(11)可知，因
Figure PCTCN2020125829-appb-000033
设
Figure PCTCN2020125829-appb-000034
则Q＝n·k。
则Q的精度受限于步长值k，k越小，即m越大，Q值越精准。
在上述第三种实施方式中，由(8)式可知，
Figure PCTCN2020125829-appb-000035
即
Figure PCTCN2020125829-appb-000036
得到公式(13)，
Figure PCTCN2020125829-appb-000037
精度
Figure PCTCN2020125829-appb-000038
n＝n1+n2。
本实施例提供的方法，因m取值为2，相比于m取值为1，采样的波峰个数增大一倍， 在保证Q值一定的情况下，测量的步长单位缩小一倍，从而使得Q值的精度提升一倍，识别异物的能力增强。比如，在m取值为1时，可能到的测量精度是1，当m取值为2时，得到的测量精度为0.5；使得原来测量的Q值的步长从整数单位变更到0.5个单位，由于步长单位变小，所以测量的结果更精确，更能够准确地判断出线圈中是否存在异物，从而提高到了测量的准确度。
应理解，所述第一参数还可以包括其他参数，使得m值大于2，进而得到测量精度单元更小，测量结果更精确。
本方法，通过全桥电路输出LC串联电路的输出电压，从而通过波峰数、波谷数或波峰数与波谷数的总和计算得到Q值，实现对充电线圈中异物的检测。
实施例二
本实施例提供另一种无线充电电路，该无线充电电路的结构与前述实施例一相似，区别在于，本实施例中，振荡电路10中的全桥电路替换为半桥电路，并且在检测电路中增加电压偏置模块。此外，所述比较模块中包括两个或两个以上比较器，进一步地，所述两个或两个以上比较器又称集成电压比较器。
具体地，如图7所示，包括：振荡电路10和检测电路20，进一步地，振荡电路10包括：激励电压源Us、半桥电路、LC串联电路以及所述LC串联电路的等效阻抗R，该等效电阻R在图7中未示出。其中，U 0为可变频的激励电压源Us的电压幅值。此外，该无线充电电路中还包括充电控制电阻R0，用于在对所述LC串联电路充电时抑制电路振荡10发生振荡。
进一步地，所述半桥电路包括第五开关管Q5和第六开关管Q6，且Q5与Q6串联，所述半桥电路的相位中点为O3，该半桥电路的一端与充电控制电阻R0相连接，另一端与激励电压源Us的负极相连接。
所述LC串联电路的一端与所述半桥电路的相位中点O3相连接，另一端接地。所述LC串联电路包括电感Lp和谐振电容Cp，且电感Lp和谐振电容Cp的相位中点为M。此外，在LC串联电路中还包括所述等效阻抗R。
所述LC串联电路的相位中点为M与检测电路20相连接，用于向检测电路20输出阻尼振荡产生的谐振电压信号，该谐振电压信号又为所述LC串联电路的相位中点M对地的电压。
所述检测电路20包括：电压偏置模块、比较模块和处理模块。其中，所述电压偏置模块与所述振荡电路连接，用于接收所述振荡电路输出的所述谐振电压信号，并将所述谐振电压信号进行偏置处理后传输给所述比较模块，所述比较模块，用于接收并将所述偏置处理后输出的谐振电压信号转换成数字方波信号，然后输出给所述处理模块。
其中，谐振电压信号Uc经过电压偏置模块处理后，输出经过偏置后的谐振电压为Uc+V ref 0，V ref 0为偏置电压。
所述比较模块的输出端与所述处理模块相连接。进一步地，所述比较模块包括第一比较器(可表示为“Com1”)和第二比较器(可表示为“Com2”)。其中，所述Com1包括输入端d1、输入端d2和输出端h1；所述Com2包括输入端g1、输入端g2和输出端h2，且所述LC串联电路的相位中点M通过所述电压偏置模块与所述Com1的输入端d2和Com2的输入端g1相连接，所述输入端d1与第一电压源相连接，所述输入端g2与第二电压源 相连接，所述Com1的输出端h1和所述Com2的输出端h2相连接，连接点为P。
其中，所述第一电压源用于向Com1提供第一参考电压V ref 1；所述第二电压源用于向Com2提供第二参考电压V ref 2。所述输入端d1和g1为同相输入端+，所述输入端d2和g2为反相输入端-。该比较模块，用于判断偏置处理后的谐振电压Uc+V ref 0是否位于第一参考电压V ref 1和第二参考电压V ref 2之间，如果是，即V ref 2≤Uc+V ref 0≤V ref 1，则输出电压为低电平。否则，输出电压为高电平，输出高电平时产生一个方波信号，形成一个上升沿。所述比较模块将产生的数字方波信号发送给所述处理模块。
其中，当所述LC串联电路的相位中点M对地的电压Uc达到所述激励电压源Us的幅值电压U 0时，所述振荡电路发生阻尼振荡并产生谐振电压，所述谐振电压经过所述电压偏置模块偏置处理后的谐振电压为Uc+V ref 0，Uc为阻尼振荡产生的所述谐振电压，V ref 0为偏置电压；所述第二预设条件为Uc+V ref 0＞V ref 1，或者Uc+V ref 0＜V ref 2，其中，V ref 1为第一参考电压，V ref 2为第二参考电压。
所述处理模块接收来自比较模块输出的数字方波信号，根据开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取所述谐振电压衰减波形中的满足第二预设条件的第二参数，以及根据所述第二参数确定Q值，根据所述品质因数Q对异物进行检测，并得到检测结果。其中，所述第二参数包括波峰数和波谷数总和。
具体地，如图8所示，所述处理模块根据第二参数确定Q值的方法，包括：
801：控制第五开关管Q5导通，第六开关管Q6关断，形成第五回路为：Us→Q5→Lp→Cp→GND→Us，此时激励电压源Us对LC串联电路充电。
802：当所述LC串联电路的相位中心M对地的电压充至所述幅值电压U 0时，控制Q5关断，Q6导通，此时所述振荡电路形成第六回路是：GND→Q6→Lp→Cp→GND，LC串联电路的电容Cp放电，振荡电路开始阻尼振荡，输出谐振电压信号Uc。所述谐振电压信号Uc从U 0开始衰减。等效电路如图5a所示，当t＝0时刻，将Q6导通，Q5关断，相当于将等效电路中的开关K从触头a拨至触头b，形成所述第六回路。所述LC串联电路输出谐振电压信号Uc给所述检测电路中的电压偏置模块。
803：电压偏置模块接收所述振荡电路输出的所述谐振电压信号，并将所述谐振电压信号进行偏置处理后传输给比较模块。
804：比较模块接收并将所述偏置的谐振电压信号转换成数字方波信号，输出给所述处理模块。
805：处理模块接收所述数字方波信号，根据开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取所述谐振电压衰减波形中的满足第二预设条件的第二参数。所述第二参数为所述波峰数和波谷数总和。
如图9所示，为一振荡电路中谐振电压Uc衰减波形的示意图，其中，V ref 0为偏置电压，V ref 1表示第一参考电压，V ref 2表示第二参考电压，U 0+V ref 0表示振荡电路产生的幅值电压U 0经过偏置电压V ref 0处理后输出的电压，Uc为LC串联电路的相位中点M对地的电压，也称谐振电压，该谐振电压的最大幅值为U 0；此外，偏置电压与第一参考电压和第二参考电压之间的电压差满足ΔV＝V ref 1-V ref 0＝V ref 0-V ref 2，f为谐振频率。
在每半个周期内，如果满足第二预设条件，即Uc+V ref 0＞V ref 1，则输出一高电平，产生一个上升沿，所述上升沿的起始时刻为偏置后的谐振电压与第一参考电压V ref 1的交点，如图9所示产生实线的方波信号。如果Uc+V ref 0＜V ref 2，则输出一高电平，产生一个上升沿，所述上升沿的起始时刻为偏置后的谐振电压与第二参考电压V ref 2的交点，如图9所示产生虚线的方波信号。如果不满足所述第二预设条件，即V ref 2≤Uc+V ref 0≤V ref 1，则不产生高电平，输出低电平信号。所述波峰数和波谷数总和n等于上升沿个数相同。
806：所述处理模块根据所述第二参数(波峰数和波谷数总和)确定品质因数Q。
计算所述Q值的表达式为：
Figure PCTCN2020125829-appb-000039
其中，m、n为正整数，m≥1，Uc为所述振荡电路输出的谐振电压，且Uc的最大值为U 0，U 0激励电压源Us的电压幅值，ΔV为电压差，且ΔV＝V ref 1-V ref 0＝V ref 0-V ref 2，V ref 0为偏置电压，V ref 1为第一参考电压，V ref 2为第二参考电压。
进一步地，本实施例中，当m＝2时，所述品质因数Q为：
Figure PCTCN2020125829-appb-000040
具体地，上述公式(14)的运算过程可参见前述实施例一中公式的计算过程，不再赘述。
807：所述处理模块根据所述品质因数Q对异物进行检测，并得到检测结果。
具体地，处理模块根据该Q值确定无线充电线圈中是否存在异物的方法与前述实施例一相同，本实施例对此不再赘述。
本实施例提供的无线充电电路，通过比较模块检测半周期内的波峰和波谷总数，进而计算出Q值，相比于采用一个电压比较器来计算Q值来说，测量的步长单位缩小一倍，由于步长单位变小，所以测量的结果更精确，更能够准确地判断出线圈中是否存在异物，从而使得Q值的检测精度提升一倍，增强了识别异物的能力。
此外，可选的，在另一种无线充电电路的结构中，如图10所示，所述LC串联电路中的电感Lp与谐振电容Cp位置互换，则发送阻尼振荡后产生的阻尼振荡电压衰减波形，如图11所示，经过偏置后的谐振电压Uc+V ref 0从-(U 0-V ref 0)开始振荡衰减，如果Uc+V ref 0＞V ref 1，则输出一高电平，产生一个上升沿，所述上升沿的起始时刻为偏置后的谐振电压与第一参考电压V ref 1的交点，如图11所示产生实线的方波信号。如果Uc+V ref 0＜V ref 2，则输出一高电平，此时，满足所述第二预设条件，产生一个上升沿，所述上升沿的起始时刻为偏置后的谐振电压与第二参考电压V ref 2的交点，如图11所示产生虚线的方波信号。如果V ref 2≤Uc+V ref 0≤V ref 1，则不满足所述第二预设条件，不产生高电平，输出低电平信号。
另外，上述实施例所述的处理模块可以是一种处理芯片或处理装置。如图12所示，包括处理器1201和存储器1202，所述处理器1201与存储器1202耦合。此外，该处理模块还可以包括更多或更少的部件，或者组合某些部件，或者不同的部件布置，本申请对此 不进行限定。
进一步地，处理器1201为处理模块的控制中心，利用各种接口和线路连接整个装置的各个部分，通过运行或执行存储在存储器1202内的软件程序或模块，以及调用存储在存储器1202内的数据，以执行相应的功能。
处理器1201可以由集成电路(integrated circuit，IC)组成，例如可以由单颗封装的IC所组成，也可以由连接多颗相同功能或不同功能的封装IC而组成。举例来说，处理器1201可以包括中央处理器(central processing unit，CPU)等。
存储器1202可以包括易失性存储器(volatile memory)，例如随机存取内存(random access memory，RAM)；还可以包括非易失性存储器(non-volatile memory)，例如快闪存储器(flash memory)，硬盘(hard disk drive，HDD)或固态硬盘(solid-state drive，SSD)；存储器1202还可以包括上述种类的存储器的组合。存储器中可以存储有程序或代码或者数据。
此外，本申请还提供一种计算机存储介质，其中，该计算机存储介质可存储有程序，该程序执行时可包括本申请提供的Q值确定方法，以及图4a、图4b和图8所示的各实施例中的部分或全部步骤。所述的存储介质可为磁碟、光盘、只读存储记忆体ROM或随机存储记忆体RAM等。
在上述实施例中，可以全部或部分通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。
所述计算机程序产品包括一个或多个计算机指令，例如计算指令，在计算机加载和执行所述计算机程序时，全部或部分地产生按照本申请上述各个实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络或者其他可编程装置。并且，所述计算机指令可以存储在计算机可读存储介质中。
所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等存储设备。所述可用介质可以是磁性介质，例如软盘、硬盘、磁带、光介质(例如DVD)、或半导体介质，例如固态硬盘SSD等。
应理解，本申请提供的一种无线充电设备，包括但不限于上述实施例一和实施例二中所述的无线充电电路的电路结构。其中，所述无线充电电路中的处理模块可以是如图12所示的处理芯片或处理装置，用于执行前述图4a、4b或图8所述的确定Q值的方法。
另外，需要说明的是，本申请各实施例的确定Q值方法除了应用于发射端设备之外，还可以应用于接收端设备，比如待充电设备为手机。并且，所述确定Q值方法，以及异物检测方法不仅仅应用于对手机无线充电环境的检测，还可以应用于其他充电环境检测，比如车载充电。
本申请实施例还提供了一种无线充电系统，所述系统包括发送设备和接收设备。其中，所述发送设备为前述实施例中的无线充电设备，所述接收设备为待充电设备。进一步地，所述无线充电设备包括前述实施例一或实施例二中的无线充电电路，用于实现本申请实施例所述的确定Q值方法，以及对无线充电线圈中异物进行检测。
其中，所述发送设备为无线充电设备，所述接收设备为待充电设备。
可选的，所述接收设备也包括前述实施例一或实施例二中的无线充电电路，用于实现本申请实施例所述的确定Q值方法，以及具备对无线充电线圈中异物进行检测的功能。
具体地，所述接收设备包括：依次连接的振荡电路和检测电路。
所述振荡电路包括：串联的激励电压源、全桥电路和LC串联电路，其中，所述激励电压源用于为所述LC串联电路提供稳定电压。
所述全桥电路包括并联的第一桥臂和第二桥臂，所述第一桥臂包括第一开关管Q1和第三开关管Q3，所述第二桥臂包括第二开关管Q2和第四开关管Q4。所述LC串联电路包括串联的电感和谐振电容，且所述LC串联电路的一端与所述第一桥臂的相位中点相连接，另一端与所述第二桥臂的相位中点相连接；所述LC串联电路的相位中点与所述检测电路相连接，用于向所述检测电路输出阻尼振荡的谐振电压信号。
所述检测电路包括比较模块和处理模块，所述比较模块，用于接收所述谐振电压信号，并将所述谐振电压信号转换成数字方波信号。所述处理模块，用于接收所述数字方波信号，根据开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取所述谐振电压衰减波形中的满足第一预设条件的第一参数，以及根据所述第一参数确定品质因数Q；所述第一参数包括波峰数、波谷数、或所述波峰数和所述波谷数总和。
电路连接过程以及确定Q值的方法参见上述实施例描述，此处不再赘述。
此外，所述处理模块还用于根据所述品质因数Q对异物进行检测，并得到检测结果；其中，如果所述品质因数Q小于等于第一阈值，则确定存在异物；如果所述品质因数Q大于第一阈值，且小于等于第二阈值，则确定可能存在异物；如果所述品质因数Q大于第二阈值，则确定无异物。
本申请的说明书和权利要求书及上述附图中的术语“第一”、“第二”等是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。此外，术语“包括”和“包含”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、系统、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过程、方法或设备固有的其它步骤或单元。
本说明书中各个实施例之间相同相似的部分互相参见即可。尤其，对于实施例二以及接收设备的实施例而言，由于其基本相似于方法实施例一，所以描述的比较简单，相关之处参见方法实施例一中的说明即可。
以上所述的本申请实施方式并不构成对本申请保护范围的限定。

Claims (24)

  1. 一种无线充电电路，其特征在于，包括：依次连接的振荡电路和检测电路；
    所述振荡电路包括：串联的激励电压源、全桥电路和LC串联电路，其中，所述激励电压源用于为所述LC串联电路提供稳定电压；
    所述全桥电路包括并联的第一桥臂和第二桥臂，所述第一桥臂包括第一开关管Q1和第三开关管Q3，所述第二桥臂包括第二开关管Q2和第四开关管Q4；
    所述LC串联电路包括串联的电感和谐振电容，且所述LC串联电路的一端与所述第一桥臂的相位中点相连接，另一端与所述第二桥臂的相位中点相连接；所述LC串联电路的相位中点与所述检测电路相连接，用于向所述检测电路输出阻尼振荡的谐振电压信号；
    所述检测电路包括比较模块和处理模块；
    所述比较模块，用于接收所述谐振电压信号，并将所述谐振电压信号转换成数字方波信号；
    所述处理模块，用于接收所述数字方波信号，根据开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取所述谐振电压衰减波形中的满足第一预设条件的第一参数，根据所述第一参数确定品质因数Q，以及根据所述品质因数Q对异物进行检测，并得到检测结果；所述第一参数包括波峰数、波谷数、或所述波峰数和所述波谷数总和，所述品质因数Q是表征所述振荡电路中所储能量与每周期损耗能量之比。
  2. 根据权利要求1所述的无线充电电路，其特征在于，所述第一预设条件为在每个振荡周期，所述阻尼振荡产生的谐振电压大于参考电压；
    其中，当所述LC串联电路的相位中点对地的电压达到所述激励电压源的幅值电压时，所述振荡电路发生阻尼振荡并产生所述谐振电压。
  3. 根据权利要求1或2所述的无线充电电路，其特征在于，
    所述第一参数包括波峰数，所述满足第一预设条件的波峰数为，在所述第一桥臂的第一开光管Q1断开，第三开关管Q3导通，所述第二桥臂的第二开关管Q2由导通变成关断，第四开关管Q4由关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第一预设条件的波峰个数；
    所述第一参数包括波谷数，所述满足第一预设条件的波谷数为，在所述第二桥臂的第二开关管Q2关断，第四开关管Q4导通，所述第一桥臂的第一开关管Q1由导通变成关断，第三开关管Q3由关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第一预设条件的波谷个数；
    所述第一参数包括所述波峰数和所述波谷数总和，所述总和为所述满足第一预设条件的所述波峰个数与所述满足第一预设条件的所述波峰谷数之和。
  4. 根据权利要求1至3任一项所述的无线充电电路，其特征在于，所述处理模块具体用于，根据所述第一参数确定所述品质因数Q为：
    Figure PCTCN2020125829-appb-100001
    其中，m,n均为正整数，且m≥1，U1和U2为所述谐振电压衰减波形中的任一波峰电压或任一波谷电压。
  5. 根据权利要求4所述的无线充电电路，其特征在于，当m＝2时，所述品质因数Q 为：
    Figure PCTCN2020125829-appb-100002
    其中，n为所述波峰数和所述波谷数总和。
  6. 一种无线充电电路，其特征在于，包括：依次连接的振荡电路和检测电路；
    所述振荡电路包括：串联的激励电压源、半桥电路和LC串联电路，其中，所述激励电压源用于为所述LC串联电路提供稳定电压；
    所述半桥电路包括串联的第五开关管Q5和第六开关管Q6；
    所述LC串联电路包括串联的电感和谐振电容，且所述LC串联电路的一端与所述半桥电路的相位中点相连接，另一端接地；所述LC串联电路的相位中点与所述检测电路相连接，用于向所述检测电路输出阻尼振荡的谐振电压信号；
    所述检测电路包括：电压偏置模块、比较模块和处理模块；
    所述电压偏置模块与所述振荡电路连接，用于接收所述振荡电路输出的所述谐振电压信号，并将所述谐振电压信号进行偏置处理后传输给所述比较模块；
    所述比较模块，用于接收并将所述偏置的谐振电压信号转换成数字方波信号，再输出给所述处理模块；
    所述处理模块，用于接收所述数字方波信号，根据开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取所述谐振电压衰减波形中的满足第二预设条件的第二参数，根据所述第二参数确定品质因数Q，以及根据所述品质因数Q对异物进行检测，并得到检测结果；所述第二参数包括波峰数和波谷数总和，所述品质因数Q是表征所述振荡电路中所储能量与每周期损耗能量之比。
  7. 根据权利要求6所述的无线充电电路，其特征在于，所述第二预设条件为：
    Uc+V ref0＞V ref1，或者Uc+V ref0＜V ref2，
    其中，Uc为阻尼振荡产生的谐振电压，V ref0为偏置电压，Uc+V ref0为经过所述电压偏置模块偏置处理后的谐振电压，V ref1为第一参考电压，V ref2为第二参考电压；
    并且，当所述LC串联电路的相位中点对地的电压达到所述激励电压源Us的幅值电压时，所述振荡电路发生阻尼振荡并产生所述谐振电压。
  8. 根据权利要求7所述的无线充电电路，其特征在于，所述波峰数和波谷数的总和为，在所述第五开关管Q5由导通变成关断，所述第六开关管Q6关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第二预设条件的所述波峰数和波谷数总和。
  9. 根据权利要求6至8任一项所述的无线充电电路，其特征在于，所述比较模块的输入端与所述电压偏置模块的输出端相连接，输出端与所述处理模块相连接；
    其中，所述比较模块中包括第一比较器和第二比较器；
    所述第一比较器和所述第二比较器均包括第一输入端、第二输入端和输出端；
    所述第一比较器的第一输入端与第一电压源相连接，用于获取所述第一电压源提供的第一参考电压；
    所述第一比较器的第二输入端与所述第二比较器的第一输入端相连接，作为所述比较模块的输入端；
    所述第二比较器的第二输入端与第二电压源相连接，用于获取第二电压源提供的第二参考电压；
    所述第一比较器的输出端与所述第二比较器的输出端相连接。
  10. 根据权利要求6至9任一项所述的无线充电电路，其特征在于，所述处理模块具体用于，根据所述第二参数确定所述品质因数Q为：
    Figure PCTCN2020125829-appb-100003
    其中，n，m均为正整数，且m≥1，U 0为所述激励电压源的电压幅值，ΔV为偏置电压与参考电压之间的电压差，所述参考电压为第一参考电压或第二参考电压。
  11. 根据权利要求10所述的无线充电电路，其特征在于，当m＝2时，所述品质因数Q为：
    Figure PCTCN2020125829-appb-100004
    其中，n为所述波峰数和所述波谷数的总和。
  12. 一种无线充电方法，其特征在于，所述方法应用于一种无线充电电路，所述无线充电电路包括依次连接的振荡电路和检测电路；
    其中，所述振荡电路包括：串联的激励电压源、全桥电路和LC串联电路，其中，所述激励电压源用于为所述LC串联电路提供稳定电压；所述全桥电路包括并联的第一桥臂和第二桥臂，所述第一桥臂包括第一开关管Q1和第三开关管Q3，所述第二桥臂包括第二开关管Q2和第四开关管Q4；所述LC串联电路包括串联的电感和谐振电容，且所述LC串联电路的一端与所述第一桥臂的相位中点相连接，另一端与所述第二桥臂的相位中点相连接；所述LC串联电路的相位中点与所述检测电路相连接，用于向所述检测电路输出阻尼振荡的谐振电压信号；所述检测电路包括比较模块和处理模块，所述比较模块用于接收所述谐振电压信号，并将所述谐振电压信号转换成数字方波信号；
    所述方法包括：
    所述处理模块接收所述数字方波信号，所述数字方波信号由所述谐振电压信号转换生成；
    所述处理模块根据所述开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取根据谐振电压衰减波形中的满足第一预设条件的第一参数；所述第一参数包括波峰数、波谷数、或所述波峰数和所述波谷数总和；
    所述处理模块根据所述第一参数确定品质因数Q，以及根据所述品质因数Q对异物进行检测，并得到检测结果；所述品质因数Q是表征所述振荡电路中所储能量与每周期损耗能量之比。
  13. 根据权利要求12所述的方法，其特征在于，所述第一预设条件为在每个振荡周期，所述阻尼振荡产生的谐振电压大于参考电压；
    其中，当所述LC串联电路的相位中点对地的电压达到所述激励电压源Us的幅值电压时，所述振荡电路发生阻尼振荡并产生所述谐振电压。
  14. 根据权利要求12或13所述的方法，其特征在于，
    所述第一参数包括波峰数，所述满足第一预设条件的波峰数为，在所述第一桥臂的第一开光管Q1断开，第三开关管Q3导通，所述第二桥臂的第二开关管Q2由导通变成关断，第四开关管Q4由关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第一预设条件的波峰个数；
    所述第一参数包括波谷数，所述满足第一预设条件的波谷数为，在所述第二桥臂的第二开关管Q2关断，第四开关管Q4导通，所述第一桥臂的第一开关管Q1由导通变成关断，第三开关管Q3由关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第一预设条件的波谷个数；
    所述第一参数包括所述波峰数和所述波谷数总和，所述总和为所述满足第一预设条件的所述波峰个数与所述满足第一预设条件的所述波峰谷数之和。
  15. 根据权利要求12至14任一项所述的方法，其特征在于，所述处理模块根据所述第一参数确定品质因数Q，包括：
    所述处理模块根据所述第一参数确定所述品质因数Q为：
    Figure PCTCN2020125829-appb-100005
    其中，n，m均为正整数，且m≥1，U1和U2为所述谐振电压衰减波形中的任一波峰电压或任一波谷电压。
  16. 根据权利要求15所述的方法，其特征在于，当m＝2时，所述品质因数Q为：
    Figure PCTCN2020125829-appb-100006
    其中，n为所述波峰数和所述波谷数总和。
  17. 一种无线充电方法，其特征在于，所述方法应用于一种无线充电电路，所述无线充电电路包括依次连接的振荡电路和检测电路；
    其中，所述振荡电路包括：串联的激励电压源、半桥电路和LC串联电路，其中，所述激励电压源用于为所述LC串联电路提供稳定电压；所述半桥电路包括串联的第五开关管Q5和第六开关管Q6；所述LC串联电路包括串联的电感和谐振电容，且所述LC串联电路的一端与所述半桥电路的相位中点相连接，另一端接地；所述LC串联电路的相位中点与所述检测电路相连接，用于向所述检测电路输出阻尼振荡的谐振电压信号；
    所述检测电路包括：电压偏置模块、比较模块和处理模块；
    所述电压偏置模块接收所述谐振电压信号，并将所述谐振电压信号进行偏置处理后传输给所述比较模块；
    所述比较模块接收并将所述偏置的谐振电压信号转换成数字方波信号，再输出给所述处理模块；
    所述方法包括：
    所述处理模块接收所述数字方波信号；
    所述处理模块根据开关管Q1至Q4的导通和关断获取阻尼振荡的谐振电压衰减波形，并获取所述谐振电压衰减波形中的满足第二预设条件的第二参数，所述第二参数包括波峰数和波谷数总和；
    所述处理模块根据所述第二参数确定品质因数Q，以及根据所述品质因数Q对异物进 行检测，并得到检测结果；所述品质因数Q是表征所述振荡电路中所储能量与每周期损耗能量之比。
  18. 根据权利要求17所述的方法，其特征在于，所述第二预设条件为：
    Uc+V ref0＞V ref1，或者Uc+V ref0＜V ref2，
    其中，Uc为阻尼振荡产生的谐振电压，V ref0为偏置电压，Uc+V ref0为经过所述电压偏置模块偏置处理后的谐振电压，V ref1为第一参考电压，V ref2为第二参考电压；
    并且，当所述LC串联电路的相位中点对地的电压达到所述激励电压源Us的幅值电压时，所述振荡电路发生阻尼振荡并产生所述谐振电压。
  19. 根据权利要求18所述的方法，其特征在于，所述波峰数和波谷数的总和为，在所述第五开关管Q5由导通变成关断，所述第六开关管Q6关断变成导通的情况下，所述处理模块根据所述比较模块输出的所述数字方波信号，确定的满足所述第二预设条件的所述波峰数和波谷数的总和。
  20. 根据权利要求17至19任一项所述的方法，其特征在于，所述处理模块根据所述第二参数确定品质因数Q，包括：
    所述处理模块根据所述第二参数确定所述品质因数Q为：
    Figure PCTCN2020125829-appb-100007
    其中，n，m均为正整数，且m≥1，U 0为所述激励电压源的电压幅值，ΔV为偏置电压与参考电压之间的电压差，所述参考电压为第一参考电压或第二参考电压。
  21. 根据权利要求20所述的方法，其特征在于，当m＝2时，所述品质因数Q为：
    Figure PCTCN2020125829-appb-100008
    其中，n为所述波峰数和所述波谷数的总和。
  22. 一种设备，所述设备为发送设备或者接收设备，其特征在于，
    所述发送设备或者接收设备包含如权利要求1至11任一项所述的无线充电电路，用于实现如权利要求12至21任一项所述的方法。
  23. 一种无线充电系统，其特征在于，所述系统包括发送设备和接收设备；
    所述发送设备包含如权利要求1至11任一项所述的无线充电电路，所述接收设备为待充电设备。
  24. 根据权利要求23所述的系统，其特征在于，所述接收设备包含如权利要求1至11任一项所述的无线充电电路。
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