CN113895251B - Foreign matter detection circuit and method of wireless charging system of electric automobile - Google Patents

Foreign matter detection circuit and method of wireless charging system of electric automobile Download PDF

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Publication number
CN113895251B
CN113895251B CN202111023015.6A CN202111023015A CN113895251B CN 113895251 B CN113895251 B CN 113895251B CN 202111023015 A CN202111023015 A CN 202111023015A CN 113895251 B CN113895251 B CN 113895251B
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China
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module
power tube
coil module
coil
impedance
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CN113895251A (en
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陈锋
刘洪亮
寇秋林
周大方
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Shanghai Kuchong Electronic Technology Co ltd
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Shanghai Kuchong Electronic Technology Co ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/10—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by the energy transfer between the charging station and the vehicle
    • B60L53/12—Inductive energy transfer
    • B60L53/124—Detection or removal of foreign bodies
    • 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
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/14—Plug-in electric vehicles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/16—Information or communication technologies improving the operation of electric vehicles

Abstract

The invention provides a foreign matter detection circuit and method of an electric automobile wireless charging system, comprising the following steps: the vehicle-mounted end circuit comprises a first driving module, a first resonance module and a second resonance module; the ground end circuit comprises a first conversion module, a second driving module, a measuring module, a switch module and at least one third coil module; the impedance is periodically changed through alternate on-off of the first resonant module and the second resonant module, the sensing voltage is detected through the measuring module when the third coil module senses the periodic change of the impedance, the impedance is also changed when the sensing voltage is changed, the existence of the metal foreign matters is judged according to the change of the impedance, and the absence of the metal foreign matters is judged when the sensing voltage is not changed. The ground end circuit has the beneficial effects that the ground end circuit monitors the change of the impedance of the ground end coil in real time in a scanning mode, so that whether metal foreign matters exist between the ground end and the vehicle-mounted end or not is detected, and the running reliability of the wireless electric energy transmission system of the electric automobile is ensured.

Description

Foreign matter detection circuit and method of wireless charging system of electric automobile
Technical Field
The invention relates to the field of detection circuits, in particular to a foreign matter detection circuit and method of an electric automobile wireless charging system.
Background
The wireless charging system of the magnetic induction type electric automobile can be simply divided into a vehicle-mounted end and a ground end, the ground end realizes electric energy transmission with the vehicle-mounted end by outputting a magnetic field which changes along with time, if metal foreign matters exist between the vehicle-mounted end and the ground end in the electric energy transmission process, the metal foreign matters not only can influence the quality of the electric energy transmission, but also can cause the heating of coils of the ground end and the vehicle-mounted end due to the influence of vortex, hysteresis and the like, so that potential safety hazards are caused, even accidents are caused, and therefore, the metal foreign matters need to be detected and wireless charging is stopped in time.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a foreign matter detection circuit of a wireless charging system of an electric automobile, which comprises:
an on-board side circuit, the on-board side circuit comprising:
the input end of the first driving module is connected with the output end of a control module;
the input end of the first resonance module is connected with the output end of the first driving module, and the output end of the first resonance module is connected with a first coil module;
the input end of the second resonance module is connected with the output end of the first driving module, and the output end of the second resonance module is connected with a second coil module;
a ground side circuit, the ground side circuit comprising:
the output end of the first conversion module is connected with the input end of a processing module;
the input end of the second conversion module is connected with the output end of the processing module;
the input end of the second driving module is connected with the output end of the second conversion module;
the output end of the measuring module is connected with the input end of the first conversion module;
the input end of the switch module is respectively connected with the output end of the second driving module and the output end of the processing module, and the output end of the switch module is respectively connected with the input end of the measuring module and at least one third coil module;
the impedance of the vehicle-mounted end circuit is periodically changed through alternate on-off of the first resonance module and the second resonance module, the third coil module senses the induction voltage of the third coil module through the measurement module when the impedance of the vehicle-mounted end circuit is periodically changed, when the induction voltage is changed, the impedance of the third coil module is changed under the influence of the induction voltage, the existence of metal foreign matters between the vehicle-mounted end circuit and the ground end circuit is judged according to the impedance change, and when the induction voltage is not changed, the existence of the metal foreign matters between the vehicle-mounted end circuit and the ground end circuit is judged.
Preferably, the first resonance module includes:
the grid electrode of the first power tube is connected with the output end of the first driving module, the source electrode of the first power tube is connected with the source electrode of the second power tube, and the drain electrode of the first power tube is connected with the drain electrode of the second power tube through a first parallel capacitor;
the isolation power supply is connected with the grid electrode and the drain electrode of the second power tube through a first resistor and a second resistor respectively;
the two ends of the third resistor are respectively connected with the grid electrode and the source electrode of the first power tube;
the two ends of the second parallel capacitor are respectively connected with the first coil module and the drain electrode of the second power tube;
the anode of the first diode is connected with the source electrode of the first power tube, and the cathode of the first diode is connected with the drain electrode of the first power tube;
and the anode of the second diode is connected with the source electrode of the second power tube, and the cathode of the second diode is connected with the drain electrode of the second power tube.
Preferably, the second resonance module includes:
the grid electrode of the third power tube is connected with the output end of the first driving module, the source electrode of the third power tube is connected with the source electrode of the fourth power tube, and the drain electrode of the third power tube is connected with the drain electrode of the fourth power tube through a third parallel capacitor;
the isolation power supply is connected with the grid electrode and the drain electrode of the fourth power tube through a fourth resistor and a fifth resistor respectively;
the two ends of the sixth resistor are respectively connected with the grid electrode and the source electrode of the third power tube;
the two ends of the fourth parallel capacitor are respectively connected with the second coil module and the drain electrode of the fourth power tube;
the anode of the third diode is connected with the source electrode of the third power tube, and the cathode of the third diode is connected with the drain electrode of the third power tube;
and the anode of the fourth diode is connected with the source electrode of the fourth power tube, and the cathode of the fourth diode is connected with the drain electrode of the fourth power tube.
Preferably, the processing module includes:
the digital oscillator is connected with the second conversion module;
the first indicator lamp is respectively connected with the digital oscillator and the first conversion module;
and the second indicator lamp is connected with the digital oscillator and the first indicator lamp in parallel.
Preferably, the switch module includes:
the grid electrode of the field effect tube is connected with the processing module, the source electrode of the field effect tube is connected with the third coil module, and the drain electrode of the field effect tube is connected with a first capacitor;
the two ends of the seventh resistor are respectively connected with the first capacitor and the second driving module;
and two ends of the eighth resistor are respectively connected with an input power supply and the drain electrode of the field effect transistor.
Preferably, a foreign matter detection method of a wireless charging system of an electric automobile is applied to the foreign matter detection circuit, and specifically comprises the following steps:
step S1, the control module of the vehicle-mounted end circuit outputs two paths of pulse width modulation waves to respectively control the first resonance module and the second resonance module to be periodically switched on and off, so that the first coil module and the second coil module perform periodic conversion between resonance and vibration loss, the impedance of the first coil module and the impedance of the second coil module periodically change, and the equivalent impedance of the third coil module also periodically changes;
step S2, after the third coil module senses the periodic change of the equivalent impedance, the digital oscillator is enabled to generate two paths of orthogonal data, the first conversion module and the second conversion module respectively convert the two paths of orthogonal data into high-frequency alternating voltage signals to excite the third coil module to enter a resonance state, the measurement module is used for detecting the induced voltage of the third coil module, the total impedance of the third coil module is obtained according to the induced voltage and the current processing of the third coil module, and whether metal foreign matters exist is judged according to the change of the total impedance.
Preferably, the first resonance module includes a first power tube and a second power tube, the second resonance module includes a third power tube and a fourth power tube, and the step S1 includes:
step S11, the control module of the vehicle-mounted end circuit outputs a first pulse width modulation wave and a first pulse width modulation wave respectively, the first pulse width modulation wave controls the first power tube and the second power tube to be periodically switched on and off, and the second pulse width modulation wave controls the third power tube and the fourth power tube to be periodically switched on and off;
step S12, the ground-side circuit sends out a high-frequency detection signal, the first coil module and the second coil module are respectively mutually transformed with one third coil module, and the equivalent impedance on one third coil module is obtained according to the angular frequency of the high-frequency detection signal and the impedance processing of the first coil module, and/or the equivalent impedance on the other third coil module is obtained according to the angular frequency of the high-frequency detection signal and the impedance processing of the second coil module.
Preferably, the equivalent impedance at the third coil module in the step S12 is obtained by the following calculation formula:
wherein,
Z eq representing the equivalent impedance;
w represents the angular frequency of the high-frequency detection signal;
m represents a mutual inductance value of the first coil module and one of the third coil modules or a mutual inductance value of the second coil module and the other of the third coil modules;
Z pb representing the impedance of the first coil module or the impedance of the second coil module.
Preferably, the step S2 includes:
step S21, after the third coil module senses the periodic change of the equivalent impedance, the processing module generates two paths of orthogonal data, the first conversion module and the second conversion module respectively convert the two paths of orthogonal data into high-frequency alternating-current voltage signals, and the high-frequency alternating-current voltage signals excite the third coil module through the switch module so that the third coil module enters a resonance state;
step S22, detecting the induction voltage and the induction current of the third coil module through the measuring module, processing the induction voltage and the induction current to obtain the total impedance of the third coil module, and judging whether the metal foreign matters exist according to the change of the total impedance:
when the total impedance of the third coil module changes, judging that metallic foreign matters exist between the ground end circuit and the vehicle-mounted end circuit;
and when the total impedance of the third coil module is not changed, judging that no metal foreign matters exist between the ground end circuit and the vehicle-mounted end circuit.
Preferably, the total impedance of the third coil module in the step S22 is obtained by the following calculation formula:
wherein,
z represents the total impedance;
V MEAS representing an induced voltage of the third coil module;
i represents the current of the third coil module.
The technical scheme has the following advantages or beneficial effects: and establishing communication between the ground end circuit and the vehicle-mounted end circuit, and monitoring the change of the impedance of the ground end coil in real time by the ground end circuit in a scanning mode, so as to detect whether metal foreign matters exist between the ground end and the vehicle-mounted end and ensure the operation reliability of the wireless electric energy transmission system of the electric vehicle.
Drawings
FIG. 1 is an electrical schematic diagram of a vehicle-side circuit in accordance with a preferred embodiment of the present invention;
FIG. 2 is an electrical schematic diagram of a ground side circuit in accordance with a preferred embodiment of the present invention;
FIG. 3 is a flow chart showing the steps of the method according to the preferred embodiment of the present invention;
FIG. 4 is a flowchart showing the steps S1 according to the preferred embodiment of the present invention;
fig. 5 is a flowchart showing the step S2 in the preferred embodiment of the present invention.
Detailed Description
The invention will now be described in detail with reference to the drawings and specific examples. The present invention is not limited to the embodiment, and other embodiments may fall within the scope of the present invention as long as they conform to the gist of the present invention.
In accordance with the foregoing problems of the prior art, the present invention provides a foreign matter detection circuit of a wireless charging system of an electric vehicle, as shown in fig. 1 and 2, comprising:
an on-board side circuit, the on-board side circuit comprising:
the input end of the first driving module 1 is connected with the output end of a control module 2;
the input end of the first resonance module 3 is connected with the output end of the first driving module 1, and the output end of the first resonance module 3 is connected with a first coil module L1;
the input end of the second resonance module 4 is connected with the output end of the first driving module 1, and the output end of the second resonance module 4 is connected with a second coil module L2;
ground side circuit, ground side circuit includes:
the output end of the first conversion module 5 is connected with the input end of a processing module 6;
the input end of the second conversion module 7 is connected with the output end of the processing module 6;
the input end of the second driving module 8 is connected with the output end of the second conversion module 7;
the output end of the measuring module 9 is connected with the input end of the first conversion module 5;
the input end of the switch module 10 is respectively connected with the output end of the second driving module 8 and the output end of the processing module 6, and the output end of the switch module 10 is respectively connected with the input end of the measuring module 9 and at least one third coil module 11;
the impedance of the vehicle-mounted end circuit is periodically changed through the alternate on-off of the first resonance module 3 and the second resonance module 4, the induction voltage of the third coil module 11 is detected through the measurement module 9 when the third coil module 11 senses the periodic change of the impedance of the vehicle-mounted end circuit, when the induction voltage is changed, the impedance of the third coil module 11 is changed under the influence of the induction voltage, the existence of metal foreign matters between the vehicle-mounted end circuit and the ground end circuit is judged according to the impedance change, and when the induction voltage is not changed, the absence of the metal foreign matters between the vehicle-mounted end circuit and the ground end circuit is judged.
In a preferred embodiment of the invention, the first resonant module 3 comprises:
the power supply comprises a first power tube Q1 and a second power tube Q2, wherein a grid electrode of the first power tube Q1 is connected with an output end of a first driving module 1, a source electrode of the first power tube Q1 is connected with a source electrode of the second power tube Q2, and a drain electrode of the first power tube Q1 is connected with a drain electrode of the second power tube Q2 through a first parallel capacitor;
the isolation power supply U1 is connected with the grid electrode and the drain electrode of the second power tube Q2 through a first resistor R1 and a second resistor R2 respectively;
the two ends of the third resistor R3 are respectively connected with the grid electrode and the source electrode of the first power tube Q1;
the two ends of the second parallel capacitor are respectively connected with the first coil module L1 and the drain electrode of the second power tube Q2;
the anode of the first diode D1 is connected with the source electrode of the first power tube Q1, and the cathode of the first diode D1 is connected with the drain electrode of the first power tube Q1;
and the anode of the second diode D2 is connected with the source electrode of the second power tube Q2, and the cathode of the second diode D2 is connected with the drain electrode of the second power tube Q2.
Specifically, in this embodiment, the first parallel capacitor includes a capacitor C1 and a capacitor C2, and the second parallel capacitor includes a capacitor C3 and a capacitor C4.
In a preferred embodiment of the invention, the second resonant module 4 comprises:
the grid electrode of the third power tube Q3 is connected with the output end of the first driving module 1, the source electrode of the third power tube Q3 is connected with the source electrode of the fourth power tube Q4, and the drain electrode of the third power tube Q3 is connected with the drain electrode of the fourth power tube Q4 through a third parallel capacitor;
the isolation power supply U1 is connected with the grid electrode and the drain electrode of the fourth power tube Q4 through a fourth resistor R4 and a fifth resistor R5 respectively;
the two ends of the sixth resistor R6 are respectively connected with the grid electrode and the source electrode of the third power tube Q3;
the two ends of the fourth parallel capacitor are respectively connected with the second coil module L2 and the drain electrode of the fourth power tube Q4;
the anode of the third diode D3 is connected with the source electrode of the third power tube Q3, and the cathode of the third diode D3 is connected with the drain electrode of the third power tube Q3;
and the anode of the fourth diode D4 is connected with the source electrode of the fourth power tube Q4, and the cathode of the fourth diode D4 is connected with the drain electrode of the fourth power tube Q4.
Specifically, in this embodiment, the isolation power supply U1 uses 3.3V to supply power, and provides pull-up for the drains of the first power tube Q1, the second power tube Q2, the third power tube Q3 and the fourth power tube Q4, so that the first power tube Q1 and the second power tube Q2 can realize on-off of an ac signal, and the third power tube Q3 and the fourth power tube Q4 can realize on-off of an ac signal.
Specifically, in the present embodiment, the third parallel capacitor includes a capacitor C5 and a capacitor C6, and the fourth parallel capacitor includes a capacitor C7 and a capacitor C8.
In a preferred embodiment of the invention, the processing module 6 comprises:
a digital oscillator NOC connected to the second conversion module 7;
a first indicator light LED1 connected to the digital oscillator NOC and the first conversion module 5, respectively;
a second indicator lamp LED2 is connected in parallel with the digital oscillator NOC and the first indicator lamp LED 1.
In a preferred embodiment of the present invention, the switch module 10 comprises:
the grid electrode of the field effect tube Q5 is connected with the processing module 6, the source electrode of the field effect tube Q5 is connected with the third coil module 11, and the drain electrode of the field effect tube Q5 is connected with the first capacitor C9;
a seventh resistor R7, two ends of the seventh resistor R7 are respectively connected to the first capacitor C9 and the second driving module 8;
and two ends of the eighth resistor R8 are respectively connected with the input power supply VCC and the drain electrode of the field effect transistor Q5.
In a preferred embodiment of the present invention, a foreign object detection method of a wireless charging system of an electric vehicle is applied to a foreign object detection circuit, as shown in fig. 3, and specifically includes the following steps:
step S1, a control module 2 of a vehicle-mounted end circuit outputs two paths of pulse width modulation waves to respectively control a first resonance module 3 and a second resonance module 4 to periodically switch on and off, so that the first coil module L1 and the second coil module L2 periodically switch between resonance and vibration loss, the impedance of the first coil module L1 and the impedance of the second coil module L2 periodically change, and the equivalent impedance of the third coil module 11 also periodically changes;
step S2, after the third coil module 11 senses the periodic variation of the equivalent impedance, the digital oscillator NOC is enabled to generate two paths of orthogonal data, the first conversion module 5 and the second conversion module 7 respectively convert the two paths of orthogonal data into high-frequency ac voltage signals to excite the third coil module 11 to enter a resonance state, the measurement module 9 detects the induced voltage of the third coil module 11, the total impedance of the third coil module 11 is obtained according to the induced voltage and the current processing of the third coil module 11, and whether the metal foreign matters exist is judged according to the variation of the total impedance.
Specifically, in this embodiment, the first conversion module 5 is an AD converter, and the second conversion module 7 is a DA converter, for converting two paths of orthogonal data into high-frequency ac voltage signals, respectively.
In a preferred embodiment of the present invention, the first resonant module 3 includes a first power tube Q1 and a second power tube Q2, the second resonant module 4 includes a third power tube Q3 and a fourth power tube Q4, as shown in fig. 4, the step S1 includes:
step S11, a control module 2 of the vehicle-mounted end circuit outputs a first pulse width modulation wave and a first pulse width modulation wave respectively, the first pulse width modulation wave controls a first power tube Q1 and a second power tube Q2 to be periodically switched on and off, and the second pulse width modulation wave controls a third power tube Q3 and a fourth power tube Q4 to be periodically switched on and off;
in step S12, the ground-side circuit sends out a high-frequency detection signal, the first coil module L1 and the second coil module L2 are respectively mutually transformed with a third coil module 11, and the equivalent impedance on one of the third coil modules 11 is obtained according to the angular frequency of the high-frequency detection signal and the impedance processing of the first coil module L1, and/or the equivalent impedance on the other third coil module 11 is obtained according to the angular frequency of the high-frequency detection signal and the impedance processing of the second coil module L2.
Specifically, in this embodiment, when the first power tube Q1 is turned on, the second power tube Q2 is turned off, the first coil module L1 enters a resonance state, at this time, the impedance of the first coil module L1 is approximately 0, when the first power tube Q1 is turned off, the second power tube Q2 is turned on, the first coil module L1 enters a vibration-losing state, at this time, the impedance of the first coil module L1 is not 0, so that the impedance of the first coil module L1 changes periodically along with the on-off of the first power tube Q1 and the second power tube Q2, and because of the coupling between the first coil module L1 and the third coil module 11, the impedance of the third coil module 11 is also affected to generate periodic changes, that is, the equivalent impedance of the first coil module L1 on the third coil module 11 will generate periodic changes, and the influence of the second coil module L2 on the third coil module 11 is the same as that of the first coil module L1.
In the preferred embodiment of the present invention, the equivalent impedance on the third coil module 11 in step S12 is obtained by the following calculation formula:
wherein,
Z eq representing the equivalent impedance;
w represents the angular frequency of the high-frequency detection signal;
m represents a mutual inductance value of the first coil module L1 and one of the third coil modules 11 or a mutual inductance value of the second coil module L2 and the other third coil module 11;
Z pb the impedance of the first coil block L1 or the impedance of the second coil block L2 is represented.
In a preferred embodiment of the present invention, as shown in fig. 5, step S2 includes:
step S21, after the third coil module 11 senses the periodic variation of the equivalent impedance, the processing module 6 generates two paths of orthogonal data, the first conversion module 5 and the second conversion module 7 respectively convert the two paths of orthogonal data into high-frequency alternating-current voltage signals, and the high-frequency alternating-current voltage signals excite the third coil module 11 through the switch module 10 so that the third coil module 11 enters a resonance state;
step S22, detecting the induced voltage and current of the third coil module 11 by the measurement module 9, obtaining the total impedance of the third coil module 11 according to the induced voltage and current processing, and judging whether the metallic foreign matter exists according to the change of the total impedance:
when the total impedance of the third coil module 11 changes, determining that a metallic foreign matter exists between the ground side circuit and the vehicle side circuit;
when the total impedance of the third coil module 11 is not changed, it is determined that no metallic foreign matter exists between the ground side circuit and the vehicle side circuit.
Specifically, in this embodiment, when the third coil module 11 senses that the equivalent impedance changes periodically, a connection can be established between the first coil module L1 and the second coil module L2, and a foreign object detection state is entered, if a metallic foreign object exists between the ground end circuit and the vehicle-mounted end circuit at this time, the impedance change of the third coil module 11 is further caused, and the impedance change of the third coil module 11 is the change of the total impedance, and when the total impedance changes, the existence of the metallic foreign object between the vehicle-mounted end circuit and the ground end circuit can be determined.
Specifically, in this embodiment, each third coil module 11 includes a ninth resistor R9, a second capacitor C10, and a first coil L3, where the ninth resistor R9, the second capacitor C10, and the first coil L3 form a series resonance detection loop, the switch module 10 is connected to a plurality of series resonance detection loops, and the processing module 6 controls the switch module 10 to conduct the series resonance detection loops by outputting a scan signal.
Preferably, the switch module 10 is connected with 64 series resonance detection circuits, the 64 detection circuits adopt a time-sharing multiplexing mode for detection, and the processing module 6 sends a scanning signal to control the switch module, so as to determine which series resonance detection circuit is conducted, and only two series resonance detection circuits are in a detection mode at the same time.
In a preferred embodiment of the present invention, the total impedance of the third coil module 11 in step S22 is obtained by the following calculation formula:
wherein,
z represents the total impedance;
V MEAS an induced voltage of the third coil module 11;
i represents the current of the third coil module 11.
In particular, in the present embodiment, due to the nature of exciting the similar constant current source, it can be considered that the current flowing through the third coil module 11 remains unchanged when the total impedance of the third coil module 11 changes, whereby the change in the total impedance can be obtained directly by the change in the induced voltage.
Specifically, in this embodiment, the basic principle and flow of ground-side circuit impedance detection are as follows:
step A1, extracting the amplitude and the phase of a high-frequency alternating current signal by using a quadrature demodulation technology, generating two paths of quadrature data by using a digital oscillator NOC by a processing module, and obtaining the data after conversion of a DA converter:
the voltage signal of the I channel is excited in the third coil block 11 after passing through the driver.
Step A2, assume that the current flowing into the third coil module 11 is:
I(t)＝I A cosωt
then, the induced current on the third coil module 11 can be expressed as follows:
step A3, sampling by an AD converter and discretizing the data, can be expressed as follows:
U ADC (n)＝G(I A Rcosωc T s -I A Xsinωi T s )
whereG：gain of amplifier
the ADC sampling signal and the signals of the I channel and the Q channel are multiplied in the FPGA respectively to obtain:
step A4, after the output signals of the two channels are passed through the digital low-pass filter, a signal component proportional to the impedance of the third coil module 11 can be obtained, where the expression is as follows:
the foregoing description is only illustrative of the preferred embodiments of the present invention and is not to be construed as limiting the scope of the invention, and it will be appreciated by those skilled in the art that equivalent substitutions and obvious variations may be made using the description and drawings, and are intended to be included within the scope of the present invention.

Claims (9)

1. Foreign matter detection circuit of wireless charging system of electric automobile, characterized by comprising:
an on-board side circuit, the on-board side circuit comprising:
the input end of the first driving module is connected with the output end of a control module;
the input end of the first resonance module is connected with the output end of the first driving module, and the output end of the first resonance module is connected with a first coil module;
the input end of the second resonance module is connected with the output end of the first driving module, and the output end of the second resonance module is connected with a second coil module;
a ground side circuit, the ground side circuit comprising:
the output end of the first conversion module is connected with the input end of a processing module;
the input end of the second conversion module is connected with the output end of the processing module;
the input end of the second driving module is connected with the output end of the second conversion module;
the output end of the measuring module is connected with the input end of the first conversion module;
the input end of the switch module is respectively connected with the output end of the second driving module and the output end of the processing module, and the output end of the switch module is respectively connected with the input end of the measuring module and at least one third coil module;
the first resonance module comprises a first power tube and a second power tube, and the second resonance module comprises a third power tube and a fourth power tube;
the impedance of the vehicle-mounted end circuit is periodically changed through the alternate on-off of the first resonance module and the second resonance module, the induction voltage of the third coil module is detected through the measurement module when the third coil module senses the periodic change of the impedance of the vehicle-mounted end circuit, when the induction voltage is changed, the impedance of the third coil module is changed under the influence of the induction voltage, the existence of metal foreign matters between the vehicle-mounted end circuit and the ground end circuit is judged according to the impedance change, and when the induction voltage is not changed, the existence of the metal foreign matters between the vehicle-mounted end circuit and the ground end circuit is judged;
the control module of the vehicle-mounted end circuit outputs a first pulse width modulation wave and a second pulse width modulation wave respectively, the first pulse width modulation wave controls the first power tube and the second power tube to be periodically switched on and off, and the second pulse width modulation wave controls the third power tube and the fourth power tube to be periodically switched on and off;
the ground end circuit sends out a high-frequency detection signal, the first coil module and the second coil module are respectively mutually transformed with one third coil module, and the equivalent impedance on one third coil module is obtained according to the angular frequency of the high-frequency detection signal and the impedance processing of the first coil module, and/or the equivalent impedance on the other third coil module is obtained according to the angular frequency of the high-frequency detection signal and the impedance processing of the second coil module.
2. The foreign object detection circuit of claim 1, wherein a gate of the first power tube is connected to an output end of the first driving module, a source of the first power tube is connected to a source of the second power tube, and a drain of the first power tube is connected to a drain of the second power tube through a first parallel capacitor;
the isolation power supply is connected with the grid electrode and the drain electrode of the second power tube through a first resistor and a second resistor respectively;
the two ends of the third resistor are respectively connected with the grid electrode and the source electrode of the first power tube;
the two ends of the second parallel capacitor are respectively connected with the first coil module and the drain electrode of the second power tube;
the anode of the first diode is connected with the source electrode of the first power tube, and the cathode of the first diode is connected with the drain electrode of the first power tube;
and the anode of the second diode is connected with the source electrode of the second power tube, and the cathode of the second diode is connected with the drain electrode of the second power tube.
3. The foreign matter detection circuit of claim 1, wherein,
the grid electrode of the third power tube is connected with the output end of the first driving module, the source electrode of the third power tube is connected with the source electrode of the fourth power tube, and the drain electrode of the third power tube is connected with the drain electrode of the fourth power tube through a third parallel capacitor;
the isolation power supply is connected with the grid electrode and the drain electrode of the fourth power tube through a fourth resistor and a fifth resistor respectively;
the two ends of the sixth resistor are respectively connected with the grid electrode and the source electrode of the third power tube;
the two ends of the fourth parallel capacitor are respectively connected with the second coil module and the drain electrode of the fourth power tube;
the anode of the third diode is connected with the source electrode of the third power tube, and the cathode of the third diode is connected with the drain electrode of the third power tube;
and the anode of the fourth diode is connected with the source electrode of the fourth power tube, and the cathode of the fourth diode is connected with the drain electrode of the fourth power tube.
4. The foreign object detection circuit of claim 1, wherein the processing module comprises:
the digital oscillator is connected with the first conversion module;
the first indicator lamp is respectively connected with the digital oscillator and the second conversion module;
and the second indicator lamp is connected with the digital oscillator and the first indicator lamp in parallel.
5. The foreign object detection circuit of claim 1, wherein the switch module includes:
the grid electrode of the field effect tube is connected with the processing module, the source electrode of the field effect tube is connected with the third coil module, and the drain electrode of the field effect tube is connected with a first capacitor;
the two ends of the seventh resistor are respectively connected with the first capacitor and the second driving module;
and two ends of the eighth resistor are respectively connected with an input power supply and the drain electrode of the field effect transistor.
6. A foreign matter detection method for a wireless charging system of an electric vehicle, applied to the foreign matter detection circuit as claimed in any one of claims 1 to 5, comprising the following steps:
step S1, the control module of the vehicle-mounted end circuit outputs two paths of pulse width modulation waves to respectively control the first resonance module and the second resonance module to be periodically switched on and off, so that the first coil module and the second coil module perform periodic conversion between resonance and vibration loss, the impedance of the first coil module and the impedance of the second coil module periodically change, and the equivalent impedance of the third coil module also periodically changes;
step S2, after the third coil module senses the periodic change of the equivalent impedance, the digital oscillator is enabled to generate two paths of orthogonal data, the first conversion module and the second conversion module respectively convert the two paths of orthogonal data into high-frequency alternating voltage signals to excite the third coil module to enter a resonance state, the measurement module is used for detecting the induction voltage of the third coil module, the total impedance of the third coil module is obtained according to the induction voltage and the current processing of the third coil module, and whether metal foreign matters exist is judged according to the change of the total impedance; the first resonance module includes a first power tube and a second power tube, the second resonance module includes a third power tube and a fourth power tube, and the step S1 includes:
step S11, the control module of the vehicle-mounted end circuit outputs a first pulse width modulation wave and a second pulse width modulation wave respectively, the first pulse width modulation wave controls the first power tube and the second power tube to be periodically switched on and off, and the second pulse width modulation wave controls the third power tube and the fourth power tube to be periodically switched on and off;
step S12, the ground-side circuit sends out a high-frequency detection signal, the first coil module and the second coil module are respectively mutually transformed with one third coil module, and the equivalent impedance on one third coil module is obtained according to the angular frequency of the high-frequency detection signal and the impedance processing of the first coil module, and/or the equivalent impedance on the other third coil module is obtained according to the angular frequency of the high-frequency detection signal and the impedance processing of the second coil module.
7. The foreign matter detection method according to claim 6, characterized in that the equivalent impedance on the third coil module in the step S12 is obtained by the following calculation formula:
wherein,
Z eq representing the equivalent impedance;
w represents the angular frequency of the high-frequency detection signal;
m represents a mutual inductance value of the first coil module and one of the third coil modules or a mutual inductance value of the second coil module and the other of the third coil modules;
Z pb representing the impedance of the first coil module or the impedance of the second coil module.
8. The foreign matter detection method according to claim 6, characterized in that the step S2 includes:
step S21, after the third coil module senses the periodic change of the equivalent impedance, the processing module generates two paths of orthogonal data, the first conversion module and the second conversion module respectively convert the two paths of orthogonal data into high-frequency alternating-current voltage signals, and the high-frequency alternating-current voltage signals excite the third coil module through the switch module so that the third coil module enters a resonance state;
step S22, detecting the induction voltage and the induction current of the third coil module through the measuring module, processing the induction voltage and the induction current to obtain the total impedance of the third coil module, and judging whether the metal foreign matters exist according to the change of the total impedance:
when the total impedance of the third coil module changes, judging that metallic foreign matters exist between the ground end circuit and the vehicle-mounted end circuit;
and when the total impedance of the third coil module is not changed, judging that no metal foreign matters exist between the ground end circuit and the vehicle-mounted end circuit.
9. The foreign matter detection method according to claim 8, characterized in that the total impedance of the third coil module in the step S22 is obtained by the following calculation formula:
wherein,
z represents the total impedance;
V MEAS representing an induced voltage of the third coil module;
i represents the current of the third coil module.
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102882282A (en) * 2011-07-14 2013-01-16 索尼公司 Power supply apparatus, power supply system, vehicle, and electronic apparatus
WO2013098133A2 (en) * 2011-12-29 2013-07-04 Conti Temic Microelectronic Gmbh Charging device for charging the energy store of a portable electric device
DE102012019584A1 (en) * 2012-10-04 2014-04-10 Panasonic Corporation Method for detecting presence of metallic foreign matter on contactless power supply device of contactless power supply system, involves determining whether metallic foreign matter is present or not based on demodulated signal
CN106560730A (en) * 2016-04-18 2017-04-12 中兴新能源汽车有限责任公司 Detection device, detection method and judgment device for metal foreign matter and wireless charging system
CN106740238A (en) * 2017-02-20 2017-05-31 华南理工大学 A kind of electric automobile wireless charging circuit and its control method
CN110626187A (en) * 2019-10-21 2019-12-31 中兴新能源汽车有限责任公司 Metal foreign matter detection device, detection method and wireless charging system
CN112550009A (en) * 2020-11-27 2021-03-26 南方科技大学 Wireless charging foreign matter detection device and electric vehicle parking auxiliary device

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11502554B2 (en) * 2020-01-23 2022-11-15 Wen Cai Methods and apparatus for online foreign object detection in wireless charging systems

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102882282A (en) * 2011-07-14 2013-01-16 索尼公司 Power supply apparatus, power supply system, vehicle, and electronic apparatus
WO2013098133A2 (en) * 2011-12-29 2013-07-04 Conti Temic Microelectronic Gmbh Charging device for charging the energy store of a portable electric device
DE102012019584A1 (en) * 2012-10-04 2014-04-10 Panasonic Corporation Method for detecting presence of metallic foreign matter on contactless power supply device of contactless power supply system, involves determining whether metallic foreign matter is present or not based on demodulated signal
CN106560730A (en) * 2016-04-18 2017-04-12 中兴新能源汽车有限责任公司 Detection device, detection method and judgment device for metal foreign matter and wireless charging system
CN106740238A (en) * 2017-02-20 2017-05-31 华南理工大学 A kind of electric automobile wireless charging circuit and its control method
CN110626187A (en) * 2019-10-21 2019-12-31 中兴新能源汽车有限责任公司 Metal foreign matter detection device, detection method and wireless charging system
CN112550009A (en) * 2020-11-27 2021-03-26 南方科技大学 Wireless charging foreign matter detection device and electric vehicle parking auxiliary device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
基于阻抗检测的多路自动调谐式无线充电金属检测系统;张亚蒙;张希;张智敏;;电工电能新技术;39(第04期);53-63 *

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