Metal foreign matter detection device and method of high-power SWPIT system

Abstract

The invention relates to the technical field of metal foreign matter detection, in particular to a metal foreign matter detection device and method for a high-power SWPIT system, and the device comprises a data communication system with adjustable power transmission, an energy coupling system, and a magnetically controlled switch module, the data communication system comprises a primary side data receiving and transmitting circuit and a secondary side data receiving and transmitting circuit with adjustable power levels, one end of the primary side data receiving and transmitting circuit and one end of the secondary side data receiving and transmitting circuit are connected to the two ends of the magnetic control switch module respectively, and through cooperation of the data communication system, the energy coupling system and the magnetic control switch module, the data communication system transmits data signals through high-frequency carrier waves; when data transmission and power transmission are performed, one coupling link is shared, so that when foreign matters appear, the foreign matters influence the data transmission and the power transmission, the existence of the foreign matters can be sensed more sensitively, the interference to foreign matter detection signals is reduced, and the accuracy of foreign matter detection is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal foreign body detection, and in particular relates to a metal foreign body detection device and method for a high-power SWPIT system. Background Art

[0002] The high-power SWPIT system is a wireless energy and information synchronous transmission system that combines wireless energy transmission and wireless information transmission functions to achieve real-time information exchange between the transmitter and the receiver. In industrial production, the presence of metal foreign matter may cause the metal foreign matter to be embedded in the products or enter the equipment, affecting the normal operation of the equipment. In order to ensure the continuous operation of the production line and reduce downtime, the high-power SWPIT system needs to be tested for metal foreign matter. At present, the metal foreign body detection method for high-power SWPIT system is usually to detect foreign body by measuring the change of magnetic flux and induced voltage of the detection coil caused by the metal foreign body. Although the influence of coupling on the detection coil parameters is fixed after the relative position between the detection coil and the transmitting coil is fixed, in a high power density environment, the strong coupling between the transmitting coil and the receiving coil may still cause non-negligible interference to the detection coil, affecting the accuracy of the detection result. Therefore, we need to propose a metal foreign body detection device and method for a high-power SWPIT system to solve the above-mentioned problems, so that it can more sensitively sense the presence of foreign body, reduce interference to the foreign body detection signal, and improve the accuracy of foreign body detection. Summary of the invention

[0003] In view of the above problems, the present invention provides a metal foreign body detection device of a high-power SWPIT system, comprising: a data communication system with adjustable power transmission, the data communication system comprising a primary data transceiver circuit and a secondary data transceiver circuit with adjustable power levels, the primary data transceiver circuit and the secondary data transceiver circuit both comprising a signal sending module and a signal receiving module; An energy coupling system, the energy coupling system comprising an energy transmitting coil and a secondary power receiving coil; A magnetically controlled switch module, the magnetically controlled switch module comprising a detection trigger unit for foreign body detection and a control response unit for on-off control; One end of the primary data transceiver circuit and one end of the secondary data transceiver circuit are respectively connected to two ends of the magnetically controlled switch module, the other end of the primary data transceiver circuit is connected to the energy transmitting coil, and the other end of the secondary data transceiver circuit is connected to the secondary power receiving coil; The primary data transceiver circuit and the secondary data transceiver circuit both transmit data signals via a high-frequency carrier wave, so that a coupling link is shared during data transmission and power transmission, ensuring that when foreign matter appears, the foreign matter does not affect both data transmission and power transmission.

[0004] Furthermore, the signal sending module and the signal receiving module located on the primary side are connected in parallel to the energy transmitting coil, and the signal sending module and the signal receiving module located on the secondary side are associated with the secondary power receiving coil. The primary side data transceiver circuit is responsible for modulating the data signal and sending it out through high-frequency carrier injection, and the secondary side data transceiver circuit receives the modulated signal from the primary side and performs demodulation processing to realize data communication between the primary side and the secondary side. The primary side data transceiver circuit and the secondary side data transceiver circuit are connected in parallel to the energy transmitting and receiving coils so that their common coupling link is used for data transmission.

[0005] Furthermore, the process of the primary data transceiver circuit modulating the data to be transmitted is as follows: A1. Set the baseband signal to m(t) and the high-frequency carrier signal to ,in, is the carrier amplitude when not modulated, is the carrier angular frequency; A2. Calculate the modulation index based on the high-frequency carrier signal , the calculation formula is as follows: ,in, is the maximum change in carrier amplitude; A3, baseband signal m(t) and high frequency carrier signal Superposition is performed to obtain the modulated signal , the superposition formula is as follows: .

[0006] Furthermore, the process of the secondary side data transceiver circuit demodulating the modulated signal received from the primary side is as follows: B11, receiving the modulated signal coupled from the primary side B12, use the rectifier diode to receive the modulated signal Perform rectification to obtain the rectified signal , the rectified signal has the following two situations: when hour, ; when hour, , indicating no signal; B13. Filter the rectified signal. The filter processing formula is as follows: , , in, is the carrier angular frequency, is the quality factor, s is the complex frequency variable, is the transfer function of the low-pass filter, is the rectified signal, is the filtered signal; B14. Perform baseband signal restoration processing on the filtered signal. The formula for baseband signal restoration is as follows: ,in, To restore the baseband signal, is the transfer function of the low-pass filter, is the signal after filtering.

[0007] Furthermore, the primary data transceiver circuit and the secondary data transceiver circuit share a coupling link during data transmission and power transmission, so that they can enter the process of power transmission and communication coordination. The process of power transmission and communication coordination is as follows: B21. Calculate the transmission power without the influence of communication signals. , the calculation formula is as follows: ,in, is the operating angular frequency, is the mutual inductance value, is the primary coil current value, is the secondary coil current value, is the coupling coefficient, and the value range of the coupling coefficient is ; B22. When the data communication system uses high-frequency carrier injection to send signals, the communication signal current will be superimposed on the current of the primary coil and the secondary coil. The total current of the primary coil is ,in, is the primary communication signal current, is the primary coil current without communication signal; the total current of the secondary coil is ,in, is the secondary side communication signal current, The secondary coil current without communication signal; B23. Calculate the new transmission power based on the total current of the primary coil and the total current of the secondary coil. , the calculation formula is as follows: ,in, is the operating angular frequency, is the mutual inductance value, is the total current value of the primary coil, is the total current value of the secondary coil, is the coupling coefficient, and the value range of the coupling coefficient is ; B24, according to the transmission power and the new transmission power Calculate the voltage amplitude of the primary communication signal and the secondary side communication signal voltage amplitude , the calculation formula is as follows: , ; B25, according to the voltage amplitude of the primary communication signal and the secondary side communication signal voltage amplitude Calculate the attenuation of the communication signal, the calculation formula is as follows: , B26, according to the calculated attenuation There are two situations to determine the attenuation degree of the communication signal: B261, when When the communication signal attenuation is small, it is judged that no power adjustment is required; B262, when When the communication signal attenuation is large, it is judged that power adjustment is required; The power adjustment method is as follows: according to the transmission power and the new transmission power Calculate the power regulation coefficient n and adjust the power according to the power regulation coefficient n. The calculation formula of the power regulation coefficient n is as follows: .

[0008] Furthermore, the energy coupling system also includes a DC-AC conversion unit, a compensation network unit, and a load unit for connecting to a DC power supply and performing DC-AC conversion on an input voltage. The compensation network unit is respectively connected to the energy transmitting coil and the secondary power receiving coil. The load is connected to one end of the compensation network unit located on the secondary side. The DC-AC conversion unit is connected to one end of the compensation network unit located on the primary side. The DC power supply is converted into an AC signal through the DC-AC conversion unit. The compensation network unit is used to improve the efficiency and performance of energy transmission. The load is used to represent a consumption device after the secondary side receives energy.

[0009] Furthermore, the compensation network unit adjusts the resonance characteristics of the circuit by connecting a capacitor C1 in series with the energy transmitting coil and a capacitor C2 in series with the secondary power receiving coil to achieve a better energy coupling effect; the process of adjusting the resonance characteristics of the compensation network unit is as follows: C11, calculate the primary resonant frequency during primary series compensation based on the primary series capacitor C1 and the inductance of the primary energy transmitting coil. The calculation formula is as follows: ,in, is the calculated primary resonant frequency, L1 is the inductance of the primary energy transmitting coil, and C1 is the capacitance of the series capacitor C1; C12, when the circuit operating frequency is equal to the primary resonant frequency When the circuit resonates, the equivalent impedance of the primary circuit is the smallest. The effective value of the primary current at resonance is calculated based on the effective value of the power supply voltage and the equivalent impedance value of the primary circuit. The calculation formula for the effective value of the primary current is as follows: ,in, is the effective value of the primary current, is the effective value of the power supply voltage, is the effective value of the primary equivalent impedance; C13. Calculate the secondary resonant frequency during secondary series compensation based on the capacitor C2 in series with the secondary side and the inductance of the secondary power receiving coil. The calculation formula is as follows: ,in, is the calculated secondary resonant frequency, L2 is the inductance of the secondary power receiving coil, and C2 is the capacitance of the series capacitor C2; C14. When the circuit resonates, the equivalent impedance value generated by the secondary induced electromotive force in the secondary circuit is the smallest. The effective value of the secondary current is calculated based on the secondary induced electromotive force and the secondary equivalent impedance value. The calculation formula for the effective value of the secondary current is as follows: ,in, is the effective value of the secondary current, is the secondary induced electromotive force, is the effective value of the secondary side equivalent impedance.

[0010] Furthermore, the process of the detection trigger unit performing foreign body detection is as follows: D11, when the system is operating normally, there is a stable magnetic field distribution between the primary side and the secondary side, and the initial magnetic field strength is set to be And set the magnetic field strength threshold of the magnetic control switch ; D12. When a foreign object appears, it will interfere with the magnetic field, causing the magnetic field strength at the magnetic control switch position to become , calculate the change in magnetic field strength , the calculation formula is as follows: ; D13. According to the calculated change in magnetic field strength With magnetic field strength threshold There are two situations for comparison: D131, when the magnetic field change meets When the magnetic switch is triggered to change state, the magnetic switch changes from the normal initial state to another state; D132, when the magnetic field change meets The magnetic switch will not be triggered to change state, that is, the magnetic switch maintains the normal initial state.

[0011] Furthermore, the process of the control response unit performing on-off control is as follows: D21, after the state of the magnetic switch changes, it will send an electrical signal to the control response unit ; D22, the control response unit receives the electrical signal from the magnetic control switch , according to the preset logic, judgment and processing are performed. If the power transmission parameters need to be adjusted, the control voltage input to the energy transmitting coil is adjusted. By changing the size or waveform of the control voltage, the primary current can be changed, thereby affecting the power transmission situation.

[0012] Based on the above-described metal foreign body detection device of a high-power SWPIT system, the present invention also provides a metal foreign body detection method of a high-power SWPIT system, comprising the following steps: S1, disconnect the magnetic switch and shut down the system; S2, check whether the secondary side is connected. If the secondary side is not connected, return to S1; if the secondary side is connected, enter S3; S3, the primary magnetic control switch is closed; S4, the primary data transmission circuit transmits the fixed data code in multiple rounds at different power levels; S5. The secondary data transceiver circuit receives data signals of different power levels and determines whether the secondary receiving circuit can correctly decode the data signals of each power level: If the decoding cannot be done correctly, it is determined that there is a foreign object and the system will alarm; If the decoding is correct, then enter S6; S6. After the secondary side can decode correctly, it sends a handshake signal to the primary side. The primary side determines whether the handshake signal is received: If it is not received, it is determined that there is a foreign object and the system alarms; If received, power transmission starts and enters S7; S7. After the power transmission starts, the secondary data transceiver circuit periodically sends data signals of different power levels to determine whether there is a handshake signal returned: If no handshake signal is returned, it is determined that there is a foreign object, and the system alarms and shuts off the power transmission; If a handshake signal is returned, power transmission is maintained and regular detection continues to monitor in real time whether there is any foreign object suddenly entering during the charging process to affect power transmission.

[0013] The beneficial effects of the present invention are: The present invention cooperates with a data communication system, an energy coupling system and a magnetically controlled switch module. The data communication system transmits data signals through a high-frequency carrier. Data transmission and power transmission share a coupling link to ensure that when foreign matter appears, the foreign matter has an impact on both data transmission and power transmission. This ensures that the presence of foreign matter can be more sensitively sensed, reducing interference with foreign matter detection signals and improving the accuracy of foreign matter detection.

[0014] The present invention uses a magnetically controlled switch module composed of a detection trigger unit and a control response unit to enable the system to perform power transmission adjustment on magnetic field changes when foreign matter appears, thereby ensuring the normal operation of the entire system.

[0015] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of the internal structure of a retort furnace body according to an embodiment of the present invention is shown; Figure 2 A flowchart of demodulating a modulated signal at a receiving primary side according to an embodiment of the present invention is shown; Figure 3 A flowchart of power transmission and communication coordination according to an embodiment of the present invention is shown; Figure 4 A flow chart of a foreign body detection method according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The embodiment of the present invention provides a metal foreign body detection device for a high-power SWPIT system, such as Figure 1-3 As shown, it includes a data communication system with adjustable power transmission, an energy coupling system and a magnetically controlled switch module. The data communication system includes a primary data transceiver circuit and a secondary data transceiver circuit with adjustable power levels. One end of the primary data transceiver circuit and one end of the secondary data transceiver circuit are respectively connected to the two ends of the magnetically controlled switch module; the energy coupling system includes an energy transmitting coil and a secondary power receiving coil. The other end of the primary data transceiver circuit is connected to the energy transmitting coil, and the other end of the secondary data transceiver circuit is connected to the secondary power receiving coil. Both the primary data transceiver circuit and the secondary data transceiver circuit transmit data signals through a high-frequency carrier, so that a coupling link is shared during data transmission and power transmission, to ensure that when a foreign object appears, the foreign object affects both data transmission and power transmission, thereby improving the sensitivity of foreign object detection.

[0020] The primary side data transceiver circuit and the secondary side data transceiver circuit both include a signal sending module and a signal receiving module. The signal sending module and the signal receiving module located at the primary side are connected in parallel to the energy transmitting coil, and the signal sending module and the signal receiving module located at the secondary side are associated with the secondary side power receiving coil. The primary side data transceiver circuit is responsible for modulating the data signal and sending it out through high-frequency carrier injection, and the secondary side data transceiver circuit receives the modulated signal from the primary side and performs demodulation processing to realize data communication between the primary side and the secondary side. The primary side data transceiver circuit and the secondary side data transceiver circuit are connected in parallel with the energy transmitting and receiving coils, so that their common coupling link is used for data transmission; When the primary data transceiver circuit transmits data by high-frequency carrier injection, the data to be transmitted is first modulated and loaded onto the high-frequency carrier signal, and then the modulated signal is sent out through the primary signal transmission module. Since the primary signal transmission module is connected in parallel with the energy transmitting coil, the modulated signal can be coupled and communicated with the secondary receiving coil by means of the energy transmitting coil. The process of the primary data transceiver circuit modulating the data to be transmitted is as follows: A1. Set the baseband signal to m(t) and the high-frequency carrier signal to ,in, is the carrier amplitude when not modulated, is the carrier angular frequency; A2. Calculate the modulation index based on the high-frequency carrier signal , the calculation formula is as follows: ,in, is the maximum change in carrier amplitude; A3, baseband signal m(t) and high frequency carrier signal Superposition is performed to obtain the modulated signal , the superposition formula is as follows: 。

[0021] As Figure 2 shown, the process of the secondary side data transceiver circuit demodulating the modulated signal received from the primary side is as follows: B11. Receive the modulated signal coupled from the primary side ; B12. Rectify the received modulated signal using a rectifying diode to obtain the rectified signal . There are the following two cases for the rectified signal: When , ; When , , indicating no signal; B13. Filter the rectified signal. The formula for the filtering process is as follows: , , where is the carrier angular frequency, is the quality factor, s is the complex frequency variable, is the transfer function of the low-pass filter, is the rectified signal, is the filtered signal; B14. Restore the filtered signal to the baseband signal. The formula for the baseband signal restoration is as follows: , where is the restored baseband signal, is the transfer function of the low-pass filter, is the filtered signal.

[0022] The primary side data transceiver circuit and the secondary side data transceiver circuit share a coupling link during data transmission and power transmission, enabling them to enter the process of power transmission and communication coordination, achieving the purpose of adjustable power transmission. As Figure 3 shown, the process of power transmission and communication coordination is as follows: B21. When there is no influence from communication signals, calculate the transmission power without the influence of communication signals . The calculation formula is as follows: , where is the working angular frequency, is the mutual inductance value, is the primary side coil current value, is the secondary side coil current value, is the coupling coefficient, and the value range of the coupling coefficient is ; B22. When the data communication system uses high-frequency carrier injection to send signals, the communication signal current will be superimposed on the current of the primary coil and the secondary coil. The total current of the primary coil is ,in, is the primary communication signal current, is the primary coil current without communication signal; the total current of the secondary coil is ,in, is the secondary side communication signal current, The secondary coil current without communication signal; B23. Calculate the new transmission power based on the total current of the primary coil and the total current of the secondary coil. , the calculation formula is as follows: ,in, is the operating angular frequency, is the mutual inductance value, is the total current value of the primary coil, is the total current value of the secondary coil, is the coupling coefficient, and the value range of the coupling coefficient is ; B24, according to the transmission power and the new transmission power Calculate the voltage amplitude of the primary communication signal and the secondary side communication signal voltage amplitude , the calculation formula is as follows: , ; B25, according to the voltage amplitude of the primary communication signal and the secondary side communication signal voltage amplitude Calculate the attenuation of the communication signal, the calculation formula is as follows: , B26, according to the calculated attenuation There are two situations to determine the attenuation degree of communication signals: B261, when When the communication signal attenuation is small, it is judged that no power adjustment is required; B262, when When the communication signal attenuation is large, it is judged that power adjustment is required; The power adjustment method is as follows: according to the transmission power and the new transmission power Calculate the power regulation coefficient n and adjust the power according to the power regulation coefficient n. The calculation formula of the power regulation coefficient n is as follows: .

[0023] When the energy transmitting coil transmits energy, an alternating current is passed through the primary side through the energy transmitting coil. According to the principle of electromagnetic induction, the alternating current will generate an alternating magnetic field around it. The alternating magnetic field will pass through the secondary side power receiving coil to achieve magnetic field coupling. The calculation formula of the alternating magnetic field strength is: ,in, is the alternating magnetic field strength, is the vacuum permeability, is the number of coil turns per unit length, is the value of the alternating current; When the secondary power receiving coil receives energy, in the alternating magnetic field generated by the primary side of the secondary power receiving coil, according to Faraday's law of electromagnetic induction, an electromotive force is induced in the secondary power receiving coil, and then an induced current is formed in the secondary power receiving coil, so that energy is transmitted from the primary side to the secondary side. In the whole process, since the communication system shares a coupling link, the magnetic field environment of energy transmission is affected by the magnetic field generated by the communication signal current; wherein, the calculation process of the electromotive force induced in the secondary power receiving coil is as follows: 1) First calculate the magnetic flux passing through the secondary power receiving coil , the calculation formula is as follows: ,in, is the alternating magnetic field strength, is the effective cross-sectional area of ​​the secondary power receiving coil, is the coupling coefficient; 2) According to magnetic flux Calculate the electromotive force using the following formula: ,in, is the magnetic flux A small change in is a small change in time, is the number of turns of the secondary power receiving coil, The energy coupling system further comprises a DC-AC conversion unit, a compensation network unit and a load unit for connecting to a DC power supply and performing DC-AC conversion on an input voltage. The compensation network unit is respectively connected to the energy transmitting coil and the secondary power receiving coil. The load is connected to one end of the compensation network unit located on the secondary side. The DC-AC conversion unit is connected to one end of the compensation network unit located on the primary side. The DC power supply is converted into an AC signal by the DC-AC conversion unit to provide an alternating current source for subsequent energy transmission through the coil. The compensation network unit is used to improve the efficiency and performance of energy transmission. By adjusting the parameters of the compensation network, the energy can be better coupled and transmitted between the primary and secondary sides, reducing energy loss, etc. The load is used to represent the consumption device after the secondary side receives the energy, reflecting the ultimate use and effect of the energy transmission.

[0024] The DC-AC conversion unit converts a DC input voltage into an AC output voltage through a DC-AC converter, and loads the AC output voltage onto the primary energy transmitting coil, so that an alternating current passes through the primary energy transmitting coil, thereby generating an alternating magnetic field, and preparing for subsequent energy coupling with the secondary power receiving coil; wherein the DC-AC converter includes an IGBT power switch device and a control circuit, and the control circuit drives the IGBT power switch device to continuously turn on and off according to a sinusoidal pulse width modulation control strategy, thereby converting the DC input into an AC output, and the voltage of the AC output has a certain frequency (e.g., the frequency is f, and the corresponding angular frequency is w=2πf) and amplitude, and its waveform can present different forms according to the modulation method adopted, for example, when SPWM modulation is adopted, the output voltage waveform is approximately a sine wave.

[0025] The compensation network unit adjusts the resonance characteristics of the circuit by connecting a capacitor C1 in series with the energy transmitting coil and a capacitor C2 in series with the secondary power receiving coil to achieve a better energy coupling effect; the process of adjusting the resonance characteristics of the compensation network unit is as follows: C11, calculate the primary resonant frequency during primary series compensation based on the primary series capacitor C1 and the inductance of the primary energy transmitting coil. The calculation formula is as follows: ,in, is the calculated primary resonant frequency, L1 is the inductance of the primary energy transmitting coil, and C1 is the capacitance of the series capacitor C1; C12, when the circuit operating frequency is equal to the primary resonant frequency When the circuit resonates, the equivalent impedance of the primary circuit is the smallest. The effective value of the primary current at resonance is calculated based on the effective value of the power supply voltage and the equivalent impedance value of the primary circuit. The calculation formula for the effective value of the primary current is as follows: ,in, is the effective value of the primary current, is the effective value of the power supply voltage, is the effective value of the primary equivalent impedance; C13. Calculate the secondary resonant frequency during secondary series compensation based on the capacitor C2 in series with the secondary side and the inductance of the secondary power receiving coil. The calculation formula is as follows: ,in, is the calculated secondary resonant frequency, L2 is the inductance of the secondary power receiving coil, and C2 is the capacitance of the series capacitor C2; C14. When the circuit resonates, the equivalent impedance value generated by the secondary induced electromotive force in the secondary circuit is the smallest. The effective value of the secondary current is calculated based on the secondary induced electromotive force and the secondary equivalent impedance value. The calculation formula for the effective value of the secondary current is as follows: ,in, is the effective value of the secondary current, is the secondary induced electromotive force, is the effective value of the secondary side equivalent impedance.

[0026] The load is the inductive current generated by the secondary power receiving coil By connecting the load RL, A voltage drop occurs across the load. , voltage drop Calculate the power PL consumed by the load. The calculation formula for power PL is: The calculated power PL is the energy transmitted from the primary side through the energy coupling system and actually used by the load, which reflects the final effect of energy transmission and completes the entire process of energy consumption from DC power supply to load. The magnetically controlled switch module includes a detection trigger unit for foreign object detection and a control response unit for on-off control. The process of the detection trigger unit for foreign object detection is as follows: D11. When the system is operating normally, there is a stable magnetic field distribution between the primary and secondary sides. The initial magnetic field strength is set to And set the magnetic field strength threshold of the magnetic control switch ; D12. When a foreign object appears, it will interfere with the magnetic field, causing the magnetic field strength at the magnetic control switch position to become , calculate the change in magnetic field strength , the calculation formula is as follows: ; D13. According to the calculated change in magnetic field strength With magnetic field strength threshold There are two situations for comparison: D131, when the magnetic field change meets When the magnetic switch is triggered to change state, the magnetic switch changes from the normal initial state to another state; D132, when the magnetic field change meets The magnetic switch will not be triggered to change state, that is, the magnetic switch maintains the normal initial state.

[0027] D21, after the state of the magnetic switch changes, it will send an electrical signal to the control response unit ; D22, the control response unit receives the electrical signal from the magnetic switch , according to the preset logic, judgment and processing are performed. If the power transmission parameters need to be adjusted, the control voltage input to the energy transmitting coil is adjusted. By changing the size or waveform of the control voltage, the primary current can be changed, thereby affecting the power transmission situation to cope with the impact of foreign matter. For example, if the primary current needs to be increased, the control voltage is increased accordingly. By detecting the magnetic control switch module composed of the trigger unit and the control response unit, the system can adjust the power transmission to the magnetic field change when foreign matter appears, thereby ensuring the normal operation of the overall system.

[0028] Through the cooperation of the data communication system, energy coupling system and magnetically controlled switch module, the data communication system transmits data signals through a high-frequency carrier, and data transmission and power transmission share a coupling link to ensure that when foreign objects appear, the foreign objects will not affect both data transmission and power transmission, so that the presence of foreign objects can be more sensitively sensed, reducing interference with foreign object detection signals and improving the accuracy of foreign object detection.

[0029] Based on the above-described metal foreign body detection device of a high-power SWPIT system, the present invention also provides a metal foreign body detection method of a high-power SWPIT system, such as Figure 4 As shown, the following steps are included: S1, disconnect the magnetic switch and shut down the system; S2, check whether the secondary side is connected. If the secondary side is not connected, return to S1; if the secondary side is connected, enter S3; S3, the primary magnetic control switch is closed; S4, the primary data transmission circuit transmits the fixed data code in multiple rounds at different power levels; S5. The secondary data transceiver circuit receives data signals of different power levels and determines whether the secondary receiving circuit can correctly decode the data signals of each power level: If the decoding cannot be done correctly, it is determined that there is a foreign object and the system will alarm; If the decoding is correct, then enter S6; S6. After the secondary side can decode correctly, it sends a handshake signal to the primary side. The primary side determines whether the handshake signal is received: If it is not received, it is determined that there is a foreign object and the system alarms; If received, power transmission starts and enters S7; S7. After the power transmission starts, the secondary data transceiver circuit periodically sends data signals of different power levels to determine whether there is a handshake signal returned: If no handshake signal is returned, it is determined that there is a foreign object, and the system alarms and shuts off the power transmission; If a handshake signal is returned, power transmission is maintained and regular detection continues to monitor in real time whether there is any foreign object suddenly entering during the charging process to affect power transmission.

[0030] The principle of foreign body detection by the above method is as follows: when the secondary side load needs to be charged, the secondary side is placed within the range of the energy transmitting coil, at this time the magnetic control switch works, the primary side magnetic control switch is turned on, and the magnetic control switch of the primary side controls the operation of the data communication system. At this time, the primary side signal sending module uses different transmission power levels to transmit the fixed data code, and performs multiple rounds of data transmission at different power levels. The secondary side signal receiving module receives the data information and determines whether the data codes of different power levels can be decoded normally. If all data codes can be decoded normally, it is determined that there is no foreign body affecting the power transmission in the power transmission system link at this time. At this time, the secondary side signal sending module sends a handshake signal to the primary side, and the primary side decodes the handshake signal and then starts the power transmission part. In order to determine whether there will be a sudden entry of foreign objects during the charging process of the system, the fixed code data transmission will be transmitted and handshaked regularly. When there is a foreign object that suddenly affects the power transmission during charging, the data transmission will also fail. At this time, the system will turn off the power transmission to ensure the safety of the system.

[0031] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A metal foreign body detection device for a high-power SWPIT system, characterized by: include: A data communication system with adjustable power transmission, the data communication system comprising a primary data transceiver circuit and a secondary data transceiver circuit with adjustable power levels, the primary data transceiver circuit and the secondary data transceiver circuit both comprising a signal sending module and a signal receiving module; An energy coupling system, the energy coupling system comprising an energy transmitting coil and a secondary power receiving coil; A magnetically controlled switch module, the magnetically controlled switch module comprising a detection trigger unit for foreign body detection and a control response unit for on-off control; One end of the primary data transceiver circuit and one end of the secondary data transceiver circuit are respectively connected to two ends of the magnetically controlled switch module, the other end of the primary data transceiver circuit is connected to the energy transmitting coil, and the other end of the secondary data transceiver circuit is connected to the secondary power receiving coil; The primary data transceiver circuit and the secondary data transceiver circuit both transmit data signals via a high-frequency carrier wave, so that a coupling link is shared during data transmission and power transmission, ensuring that when foreign matter appears, the foreign matter will not affect both data transmission and power transmission.

2. The metal foreign body detection device of a high-power SWPIT system according to claim 1, characterized in that: The signal sending module and the signal receiving module located on the primary side are connected in parallel to the energy transmitting coil, and the signal sending module and the signal receiving module located on the secondary side are associated with the secondary side power receiving coil. The primary side data transceiver circuit is responsible for modulating the data signal and sending it out through high-frequency carrier injection. The secondary side data transceiver circuit receives the modulated signal from the primary side and performs demodulation processing to realize data communication between the primary side and the secondary side. The primary side data transceiver circuit and the secondary side data transceiver circuit are connected in parallel with the energy transmitting and receiving coils so that their common coupling link is used for data transmission.

3. The metal foreign body detection device of a high-power SWPIT system according to claim 2, characterized in that: The process of the primary data transceiver circuit modulating the data to be transmitted is as follows: A1. Set the baseband signal to m(t) and the high-frequency carrier signal to ,in, is the carrier amplitude when not modulated, is the carrier angular frequency; A2. Calculate the modulation index based on the high-frequency carrier signal , the calculation formula is as follows: ,in, is the maximum change in carrier amplitude; A3, baseband signal m(t) and high frequency carrier signal Superposition is performed to obtain the modulated signal , the superposition formula is as follows: 。 4. The metal foreign body detection device of a high-power SWPIT system according to claim 3, characterized in that: The process of the secondary side data transceiver circuit demodulating the modulated signal received from the primary side is as follows: B11, receiving the modulated signal coupled from the primary side ; B12, use the rectifier diode to receive the modulated signal Perform rectification to obtain the rectified signal , the rectified signal has the following two situations: when hour, ; when hour, , indicating no signal; B13. Filter the rectified signal. The filter processing formula is as follows: ， , in, is the carrier angular frequency, is the quality factor, s is the complex frequency variable, is the transfer function of the low-pass filter, is the rectified signal, is the filtered signal; B14. Perform baseband signal restoration processing on the filtered signal. The formula for baseband signal restoration is as follows: ,in, To restore the baseband signal, is the transfer function of the low-pass filter, is the signal after filtering.

5. The metal foreign body detection device of a high-power SWPIT system according to claim 4, characterized in that: The primary data transceiver circuit and the secondary data transceiver circuit share a coupling link during data transmission and power transmission, so that they can enter the process of power transmission and communication coordination. The process of power transmission and communication coordination is as follows: B21. Calculate the transmission power without the influence of communication signals. , the calculation formula is as follows: ,in, is the operating angular frequency, is the mutual inductance value, is the primary coil current value, is the secondary coil current value, is the coupling coefficient, and the value range of the coupling coefficient is ; B22. When the data communication system uses high-frequency carrier injection to send signals, the communication signal current will be superimposed on the current of the primary coil and the secondary coil. The total current of the primary coil is ,in, is the primary communication signal current, is the primary coil current without communication signal; the total current of the secondary coil is ,in, is the secondary side communication signal current, The secondary coil current without communication signal; B23. Calculate the new transmission power based on the total current of the primary coil and the total current of the secondary coil. , the calculation formula is as follows: ,in, is the operating angular frequency, is the mutual inductance value, is the total current value of the primary coil, is the total current value of the secondary coil, is the coupling coefficient, and the value range of the coupling coefficient is ; B24, according to the transmission power and the new transmission power Calculate the voltage amplitude of the primary communication signal and the secondary side communication signal voltage amplitude , the calculation formula is as follows: ， ； B25, according to the voltage amplitude of the primary communication signal and the secondary side communication signal voltage amplitude Calculate the attenuation of the communication signal, the calculation formula is as follows: , B26, according to the calculated attenuation There are two situations to determine the attenuation degree of communication signals: B261, when When the communication signal attenuation is small, it is judged that no power adjustment is required; B262, when When the communication signal attenuation is large, it is judged that power adjustment is required; The power adjustment method is as follows: according to the transmission power and the new transmission power Calculate the power regulation coefficient n and adjust the power according to the power regulation coefficient n. The calculation formula of the power regulation coefficient n is as follows: 。 6. The metal foreign body detection device of a high-power SWPIT system according to claim 5, characterized in that: The energy coupling system also includes a DC-AC conversion unit, a compensation network unit, and a load unit, which are used to connect to a DC power supply and perform DC-AC conversion on an input voltage. The compensation network unit is respectively connected to the energy transmitting coil and the secondary power receiving coil. The load is connected to one end of the compensation network unit located on the secondary side. The DC-AC conversion unit is connected to one end of the compensation network unit located on the primary side. The DC power supply is converted into an AC signal through the DC-AC conversion unit. The compensation network unit is used to improve the efficiency and performance of energy transmission. The load is used to represent a consumption device after the secondary side receives energy.

7. The metal foreign body detection device of a high-power SWPIT system according to claim 6, characterized in that: The compensation network unit adjusts the resonance characteristics of the circuit by connecting a capacitor C1 in series with the energy transmitting coil and a capacitor C2 in series with the secondary power receiving coil to achieve a better energy coupling effect; the process of adjusting the resonance characteristics of the compensation network unit is as follows: C11, calculate the primary resonant frequency during primary series compensation based on the primary series capacitor C1 and the inductance of the primary energy transmitting coil. The calculation formula is as follows: ,in, is the calculated primary resonant frequency, L1 is the inductance of the primary energy transmitting coil, and C1 is the capacitance of the series capacitor C1; C12, when the circuit operating frequency is equal to the primary resonant frequency When the circuit resonates, the equivalent impedance of the primary circuit is the smallest. The effective value of the primary current at resonance is calculated based on the effective value of the power supply voltage and the equivalent impedance value of the primary circuit. The calculation formula for the effective value of the primary current is as follows: ,in, is the effective value of the primary current, is the effective value of the power supply voltage, is the effective value of the primary equivalent impedance; C13. Calculate the secondary resonant frequency during secondary series compensation based on the capacitor C2 in series with the secondary side and the inductance of the secondary power receiving coil. The calculation formula is as follows: ,in, is the calculated secondary resonant frequency, L2 is the inductance of the secondary power receiving coil, and C2 is the capacitance of the series capacitor C2; C14. When the circuit resonates, the equivalent impedance value generated by the secondary induced electromotive force in the secondary circuit is the smallest. The effective value of the secondary current is calculated based on the secondary induced electromotive force and the secondary equivalent impedance value. The calculation formula for the effective value of the secondary current is as follows: ,in, is the effective value of the secondary current, is the secondary induced electromotive force, is the effective value of the secondary side equivalent impedance.

8. The metal foreign body detection device of a high-power SWPIT system according to claim 7, characterized in that: The process of the detection trigger unit performing foreign body detection is as follows: D11. When the system is operating normally, there is a stable magnetic field distribution between the primary and secondary sides. The initial magnetic field strength is set to And set the magnetic field strength threshold of the magnetic control switch ; D12. When a foreign object appears, it will interfere with the magnetic field, causing the magnetic field strength at the magnetic control switch position to become , calculate the change in magnetic field strength , the calculation formula is as follows: ; D13. According to the calculated change in magnetic field strength With magnetic field strength threshold There are two situations for comparison: D131, when the magnetic field change meets When the magnetic switch is triggered to change state, the magnetic switch changes from the normal initial state to another state; D132, when the magnetic field change meets The magnetic switch will not be triggered to change state, that is, the magnetic switch maintains the normal initial state.

9. The metal foreign body detection device of a high-power SWPIT system according to claim 8, characterized in that: The process of the control response unit performing on-off control is as follows: D21, after the state of the magnetic switch changes, it will send an electrical signal to the control response unit ; D22, the control response unit receives the electrical signal from the magnetic switch , according to the preset logic, judgment and processing are performed. If the power transmission parameters need to be adjusted, the control voltage input to the energy transmitting coil is adjusted. By changing the size or waveform of the control voltage, the primary current can be changed, thereby affecting the power transmission situation.

10. A method for detecting metal foreign bodies in a high-power SWPIT system, based on a metal foreign body detection device for a high-power SWPIT system according to any one of claims 1 to 9, characterized in that: The steps include: S1, disconnect the magnetic switch and shut down the system; S2, check whether the secondary side is connected. If the secondary side is not connected, return to S1; if the secondary side is connected, enter S3; S3, the primary magnetic control switch is closed; S4, the primary data transmission circuit transmits the fixed data code in multiple rounds at different power levels; S5. The secondary data transceiver circuit receives data signals of different power levels and determines whether the secondary receiving circuit can correctly decode the data signals of each power level: If the decoding cannot be done correctly, it is determined that there is a foreign object and the system will alarm; If the decoding is correct, then enter S6; S6. After the secondary side can decode correctly, it sends a handshake signal to the primary side. The primary side determines whether the handshake signal is received: If it is not received, it is determined that there is a foreign object and the system alarms; If received, power transmission starts and enters S7; S7. After the power transmission starts, the secondary data transceiver circuit periodically sends data signals of different power levels to determine whether there is a handshake signal returned: If no handshake signal is returned, it is determined that there is a foreign object, and the system alarms and shuts off the power transmission; If a handshake signal is returned, power transmission is maintained and regular detection continues to monitor in real time whether there is any foreign object suddenly entering during the charging process to affect power transmission.

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