Extremely low frequency electromagnetic wave full duplex magnetic sensing device and method

Abstract

The present application provides an extremely low frequency electromagnetic wave full-duplex magnetic sensing device and method, which includes a controller, a first antenna module, and a second antenna module. The first antenna module and the second antenna module include an excitation unit, a mutual induction unit, a coil, a magnetic core, and a shield layer. The controller controls the first antenna module and the second antenna module to be in an asynchronous excitation state and an asynchronous mutual induction state, sequentially obtains data to be transmitted from the first antenna module and the second antenna module, and converts the data to be transmitted into an asynchronous excitation signal after performing a time delay by phase shifting, transmits the asynchronous excitation signal to the excitation unit of the first antenna module and the second antenna module to generate an asynchronous excitation current signal, receives the asynchronous induction signal by the coil of the first antenna module and the second antenna module, performs clock correction on the induction signal, and then analyzes the induction signal. The device can simultaneously perform two-way transmission of data, can complete real-time magnetic sensing alternation of various information, and can be applied to two-way communication between inside and outside in a shielded area, improving the quality and speed of data transmission.

Description

[Technical field]

[0001] This application claims priority to a Chinese patent application filed with the State Intellectual Property Office on February 6, 2023, bearing application number CN202310063770.X and entitled "Extremely low frequency electromagnetic wave full-duplex magnetic sensing device and method," the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the field of extremely low frequency sensing, and in particular to an extremely low frequency electromagnetic wave full duplex magnetic sensing device and method. [Background technology]

[0003] Extremely low frequency (EVF) is a radio wave with a frequency of 3 Hz to 30 Hz and a wavelength of 100,000 to 1,000,000 kilometers. Extremely low frequency signals can penetrate media such as seawater, rocks, and metals, and are used in fields such as resource exploration, earthquake prediction, drilling surveys, and submarine communications. Extremely low frequency electromagnetic waves have low propagation loss and attenuation in the atmosphere is less than 1 dB / thousand kilometers.

[0004] The main research direction of extremely low frequency is eddy current inspection. Eddy current inspection uses the principle of electromagnetic induction to measure the changes in induced eddy currents in the object being inspected, thereby non-destructively evaluating conductive materials and their specific performance, and is used in flaw detection, material selection, thickness measurement, dimensional measurement, and physical quantity measurement (e.g., radial amplitude, axial displacement, and motion trajectory measurement). The application and research of extremely low frequency technology makes full use of the transmission characteristics of extremely low frequency to realize the conversion and analysis of magnetic field strength into electrical signals, which are applied to flaw detection, thickness measurement, motion trajectory detection, etc., but it cannot realize two-way communication between inside and outside in a shielded area, and cannot meet the real-time alternating requirements of complex work processes. Summary of the Invention [Problem to be solved by the invention]

[0005] The present application provides an extremely low frequency electromagnetic wave full-duplex magnetic sensing device and method to solve the problem of being unable to realize two-way communication and real-time alternating requirements between inside and outside in a shielded area. [Means for solving the problem]

[0006] According to one aspect of the present application, there is provided an extremely low frequency electromagnetic wave full-duplex magnetic sensing device comprising a controller, a first antenna module, and a second antenna module, the first antenna module and the second antenna module each comprising an excitation unit, a mutual induction unit, a coil, a magnetic core, and a shield layer, Magnetic a core is provided inside the coil, the coil is provided inside the shield layer, the excitation unit and the mutual induction unit are connected to the coil such that the first antenna module and the second antenna module are in an excitation state and a mutual induction state, respectively, and the controller is connected to the excitation unit of the first antenna module and the excitation unit of the second antenna module; The controller: Controlling the first antenna module so that the first antenna module is in an excited state, and after performing a time delay by phase shifting, controlling the second antenna module so that the second antenna module is in an excited state; Get the data waiting to be sent, converting the data to be transmitted into an excitation signal according to an encoding rule of an extremely low frequency pulse sequence for representing the data to be transmitted and the received data based on a symbol envelope and a pulse sequence; Sending the excitation signal to the excitation unit of the first antenna module and the excitation unit of the second antenna module to generate an excitation current signal in the coil of the first antenna module and the coil of the second antenna module; receiving an induced signal generated by induction between the coil of the first antenna module and the coil of the second antenna module by the coil of the first antenna module and the coil of the second antenna module; performing a clock correction on the guided signal; Analyzing the corrected induced signal using the coding rule of the extremely low frequency pulse sequence to obtain received data. It is configured as follows.

[0007] Optionally, the symbol envelope includes a leading symbol, a trailing symbol, a dead band and a data packet symbol.

[0008] Optionally, the controller further comprises: The first antenna module and the second antenna module are in an asynchronous excitation state. Set it so that Alternatively, the first antenna module and the second antenna module are set to be in an asynchronous mutual induction state. It is configured as follows.

[0009] Optionally, further include an excitation current detection module and an analog-to-digital conversion module, and the coil of the first antenna module and the coil of the second antenna module are respectively connected to the controller through the excitation current detection module and the analog-to-digital conversion module in sequence; The controller: Obtain the excitation current and a preset current threshold; When the excitation current is equal to or greater than a current threshold, the excitation unit is controlled to stop generating an excitation current signal. It is configured as follows. The excitation current detection module can detect the excitation current of the coil in real time to prevent the coil from burning due to overheating, and can also monitor the software time series in real time.

[0010] Optionally, the first antenna module and the second antenna module further include a magnetic reset diode connected in parallel with the coil for completing a magnetic reset when the coil is switched between an excited state and a mutual induction state.

[0011] Optionally, the method further comprises a clock reference module and a dual frequency selective filter module; The mutual induction unit of the first antenna module and the mutual induction unit of the second antenna module are connected to the controller through the dual frequency selective filter module and the clock reference module in sequence.

[0012] Optionally, the dual frequency selective filter module comprises a first antenna module filter module and a second antenna module filter module; The first antenna module filter module is for arranging a first mutual induction frequency band in the first antenna module, and includes a frequency selection point of a first center frequency and a frequency selection point of a second center frequency; The second antenna module filter module is for arranging a second mutual induction frequency band in the second antenna module, and includes a frequency selection point of a third center frequency and a frequency selection point of a fourth center frequency.

[0013] Optionally, the first antenna module and the second antenna module further include a PMOS transistor and an NMOS transistor; the PMOS transistor, the NMOS transistor, and the coil form a half-bridge excitation circuit; The PMOS transistor and the NMOS transistor are for controlling the coil.

[0014] Optionally, the coil of the first antenna module and the coil of the second antenna module have central axes that are perpendicular to each other.

[0015] A method for extremely low frequency electromagnetic wave full-duplex magnetic sensing according to another aspect of the present application is applied to an extremely low frequency electromagnetic wave full-duplex magnetic sensing device including a controller, a first antenna module, and a second antenna module, The first antenna module and the second antenna module each include an excitation unit, a mutual induction unit, a coil, a magnetic core, and a shield layer; This method is controlling the first antenna module to be in an excited state, and performing a time delay by phase shifting, and then controlling the second antenna module to be in an excited state; obtaining pending data; converting the data to be transmitted into an excitation signal according to an encoding rule of an extremely low frequency pulse sequence for representing the data to be transmitted and the received data based on a symbol envelope and a pulse sequence; Sending the excitation signal to the excitation units of the first antenna module and the second antenna module to generate excitation current signals in the coils of the first antenna module and the second antenna module; receiving an induced signal generated by induction of the coils of the first antenna module and the second antenna module by the coils of the first antenna module and the second antenna module; performing a clock correction on the guided signal; and analyzing the corrected induced signal using the coding rule of the extremely low frequency pulse sequence to obtain received data. Effect of the Invention

[0016] According to the above technical configuration, the extremely low frequency electromagnetic wave full-duplex magnetic sensing device of the present application comprises a controller, a first antenna module, and a second antenna module, and the first antenna module and the second antenna module comprise an excitation unit, a mutual induction unit, a coil, a magnetic core, and a shield layer. Magnetic The core is provided inside the coil, the coil is provided inside the shielding layer, the excitation unit and the mutual induction unit are respectively connected to the coil, and the controller is connected to the first antenna module and the second antenna module. The controller is configured to control the first antenna module so that the first antenna module is in an excited state, and after performing a time delay by phase shift, control the second antenna module so that the second antenna module is in an excited state, obtain data to be transmitted and convert the data to be transmitted into an excitation signal, transmit the excitation signal to the excitation unit of the first antenna module to generate an excitation current signal, receive an asynchronous induction signal by the coils of the first antenna module and the second antenna module, and perform clock correction on the induction signal to receive the induction signal. The extremely low frequency electromagnetic wave full-duplex magnetic sensing method according to the present application is applied to an extremely low frequency full-duplex magnetic sensing device. The device can simultaneously perform two-way transmission of data, complete real-time magnetic sensing alternation of various information, and is applied to two-way communication between inside and outside in a shielded area, and can improve the quality and speed of data transmission. [Brief description of the drawings]

[0017] In order to more clearly explain the technical configuration of the present application, the drawings necessary for the embodiments will be briefly described below, and those skilled in the art can obtain other drawings from these drawings without creative efforts. [Figure 1] 1 is a schematic diagram of an antenna module of an extremely low frequency electromagnetic wave full-duplex magnetic sensing device. FIG. [Diagram 2] FIG. 2 is a schematic diagram of a frequency selective amplification unit. [Diagram 3]FIG. 2 is a schematic diagram of a frequency selective amplification network. [Figure 4] FIG. 2 is a schematic diagram of communication between a master station and a slave station. [Diagram 5] FIG. 1 is a schematic diagram of extremely low frequency excitation sequence generation and pulse sequence identification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The following describes the embodiments in detail, examples of which are shown in the drawings. When the following description refers to the drawings, the same numbers in different drawings refer to the same or similar elements unless otherwise stated. The embodiments described in the following examples do not represent all the embodiments consistent with the present application. They are merely examples of systems and methods consistent with some aspects of the present application, as detailed in the claims.

[0019] Due to its excellent permeability, extremely low frequency waves are used for tracking and positioning of movement in a pipeline, flaw detection, thickness measurement, and detection of movement trajectory, etc. For example, when performing tracking and positioning of movement in a pipeline, a robot in the pipeline moves continuously, and a signal transmitter attached to the robot transmits an extremely low frequency single-frequency magnetic field signal, which can penetrate the metal pipeline and the soil layer and reach the signal receiver on the ground. Although the permeability characteristics of the extremely low frequency signal are fully utilized to realize the conversion and analysis of the magnetic field intensity into an electric signal, the above application cannot realize two-way communication between inside and outside in a shielded area during work.

[0020] In order to solve the above problems, in a first aspect, the present application provides an extremely low frequency electromagnetic wave full-duplex magnetic sensing device, and FIG. 1 is a schematic diagram of an antenna module of the extremely low frequency electromagnetic wave full-duplex magnetic sensing device. As shown in FIG. 1, the extremely low frequency electromagnetic wave full-duplex magnetic sensing device according to the present application includes a controller, a first antenna module, and a second antenna module. In the present application, the first antenna module is 1#, the second antenna module is 2#, and for convenience of understanding, the controller and the antenna module of FIG. 1 are used as a master station to communicate with a slave station. In addition, the extremely low frequency electromagnetic wave full-duplex magnetic sensing device can also be used as a slave station to communicate with the master station.

[0021] The first antenna module and the second antenna module include an excitation unit, a mutual induction unit, a coil, a magnetic core, and a shield layer, and the controller is connected to the excitation unit of the first antenna module and the excitation unit of the second antenna module; Magnetic The core is provided inside the coil, and the coil is provided inside the shield layer. In order to increase the magnetic flux density of the coil, Magnetic In this embodiment, a core is provided. Magnetic The core material is permalloy. The coil of the first antenna module 1# and the coil of the second antenna module 2# are provided with a shield layer on their exteriors, and the shield layer is made of a high magnetic permeability material, which can prevent mutual interference between the magnetic lines of force of the coils 1# and 2# whose axial directions are perpendicular, thereby achieving the purpose of magnetic shielding. In this embodiment, the material of the shield layer is also permalloy. In order to minimize interference of the magnetic circuits between the two coils, the coil of the first antenna module and the coil of the second antenna module are arranged so that their central axes are perpendicular to each other.

[0022] The excitation unit and the mutual induction unit are respectively connected to the coil so that the first antenna module and the second antenna module are in an asynchronous excitation state or an asynchronous mutual induction state. As shown in FIG. 1, the excitation unit of the first antenna module includes a pull-up resistor R1, a voltage follower consisting of an operational amplifier (op-amp) U_1, a gate resistor Rg5, a gate-source resistor Rgs7, a gate-source resistor Rgs9, and an NMOS transistor VT1 for driving the upper arm. The pull-up resistor R1 is for initializing the logic state to "1" to ensure the accuracy of the excitation and mutual induction state, the voltage follower consisting of the operational amplifier U_1 provides high input resistance and low output resistance so that the front and rear stages are reliably related, the gate resistor Rg5 and the gate-source resistor Rgs7 obtain the switching signal of the NMOS transistor VT3 for driving the upper arm after dividing the voltage, and the gate-source resistor Rgs9 and the NMOS transistor VT1 for driving the upper arm jointly control the switching of the PMOS transistor VT2.

[0023] The excitation unit of the second antenna module includes a pull-up resistor R2, an inverting amplifier consisting of an operational amplifier U_2 and resistors R3 and Rf4, a gate resistor Rg6, a gate-source resistor Rgs8, a gate-source resistor Rgs10, and an upper arm driving NMOS transistor VT4. The pull-up resistor R2 initializes the logic state to "0" to ensure the accuracy of the excitation and mutual induction state, the inverting amplifier amplifies and inverts the input signal for output, the gate resistor Rg6 and the gate-source resistor Rgs8 obtain the switching signal for the upper arm driving NMOS transistor and the NMOS transistor VT6 after dividing the voltage, and the gate-source resistor Rgs10 and the upper arm driving NMOS transistor VT4 jointly control the switching of the PMOS transistor VT5.

[0024] The first antenna module and the second antenna module further include a PMOS transistor and an NMOS transistor, and the PMOS transistor, the NMOS transistor, and the coil form a half-bridge excitation circuit, and the PMOS transistor and the NMOS transistor are used to control the coil. The half-bridge structure is a structure in which two power switching elements (e.g., MOS transistors, etc.) are connected in a totem pole shape, and a square wave signal is output from the midpoint. As shown in FIG. 1, the PMOS transistor VT2 and the NMOS transistor VT3 are half-bridge excitation interlock switches for the 1# coil, and the PMOS transistor VT5 and the NMOS transistor VT6 are half-bridge excitation interlock switches for the 2# coil. The NMOS transistors VT1 and VT4 are drive switches for the upper arms of the half-bridge excitation circuits for the 1# and 2# coils, respectively.

[0025] The coils of the first antenna module and the second antenna module can be connected to two outlet terminals to form a mutual induction unit. The mutual induction unit outputs V1+, V1- which are mutual induction voltage signals of coil 1#, and V2+, V2- which are mutual induction voltage signals of coil 2#.

[0026] In some embodiments, the first antenna module and the second antenna module further include an excitation current detection module and an analog-to-digital conversion module. The excitation current detection module is connected to the excitation unit of the first antenna module and the excitation unit of the second antenna module, respectively. The excitation current detection module detects the excitation current of each coil in real time through floating measurement, and can realize the controllability of the excitation current of each coil. As shown in FIG. 1, the excitation current detection module of coil #1, which is composed of an operational amplifier U_3, a resistor R11, a capacitor C1, and a floating point FG1, and the excitation current detection module of coil #2, which is composed of an operational amplifier U_4, a resistor R12, a capacitor C2, and a floating point FG2, convert the excitation current signal of each coil into a voltage signal and output it to the analog-to-digital conversion module.

[0027] The analog-to-digital conversion module is for performing mutual conversion between analog signals and digital signals. Taking the conversion from analog signals to digital signals as an example, the analog-to-digital conversion module can collect analog signals and quantize them into digital signals encoded as binary. The linear optocoupler is a photocoupler device for isolating analog signals, and can offset the nonlinearity of the pass-through path by the nonlinearity of the feedback path to achieve the purpose of linear isolation. As shown in FIG. 1, the voltage signal converted by the excitation current detection module of the above-mentioned first antenna module passes through resistor R13, linear optocoupler_OP1 and pull-up resistor R15 to be converted into a digital signal with GND (ground) as the reference point, and input to the controller digital signal input interface AI_0. The floating point FG1 is electrically connected to the outlet terminal of the 1# coil and serves as the reference ground of the power supply VC5-1. The voltage signal converted by the excitation current detection module of the second antenna module passes through resistor R14, linear photocoupler_OP2 and pull-up resistor R16 to be converted into a digital signal with GND as the reference point, and input to the controller digital signal input interface AI_1. The floating point FG2 is electrically connected to the outlet terminal of coil 2#, and serves as the reference ground of the power supply VC5-2.

[0028] After receiving the digital signal, the controller can determine whether the excitation current value exceeds a preset current threshold, and if the excitation current is equal to or greater than the current threshold, control the excitation unit to stop generating the excitation current signal to prevent excessive current from flowing through the coil, causing the coil to overheat and burn out.

[0029] As shown in FIG. 1, the first antenna module and the second antenna module further include magnetic reset diodes, Df1 and Df2 being magnetic reset diodes for coils 1# and 2#, respectively. The magnetic reset diode Df1 is connected in parallel with coil 1#, and the magnetic reset diode Df2 is connected in parallel with coil 2#, thereby completing a magnetic reset when the coils are switched between an excited state and a mutual induction state.

[0030] In some embodiments, the first antenna module and the second antenna module further include a dual frequency selective filter module and a clock reference module. The mutual induction units of the first antenna module and the second antenna module are connected to the controller through the dual frequency selective filter module and the clock reference module in turn. The dual frequency selective filter module can select and amplify the frequency of the signal received by the mutual induction coil, and the extremely low frequency (ELF) of each coil does not overlap, which makes subsequent software analysis easier. The center frequency is defined as the midpoint between both 3 dB points of the band pass filter and is denoted as the arithmetic mean. The dual frequency selective filter module includes a first antenna module filter module and a second antenna module filter module, the first antenna module filter module is for arranging a first mutual induction frequency band in the first antenna module and includes a frequency selection point of a first center frequency and a frequency selection point of a second center frequency, and the second antenna module filter module is for arranging a second mutual induction frequency band in the second antenna module and includes a frequency selection point of a third center frequency and a frequency selection point of a fourth center frequency.

[0031] FIG. 2 is a schematic diagram of a frequency selective amplification unit. As shown in FIG. 2, a first resistor R1_i, a second resistor R2_i, a third resistor R3_i, a first capacitor C1_i, a second capacitor C2_i and an operational amplifier U1_i constitute a frequency selection point of a first center frequency, and a fourth resistor R4_i, a fifth resistor R5_i, a sixth resistor R6_i, a third capacitor C3_i, a fourth capacitor C4_i and an operational amplifier U2_i constitute a frequency selection point of a second center frequency.

[0032] As shown in FIG. 3, FIG. 3 is a schematic diagram of a frequency selective amplification network. FIG. 2 is a frequency selective amplification unit located in the dotted frame of FIG. 3, and the dotted frame part of FIG. 3 is a dual frequency selective filter module. The frequency selective amplification unit of FIG. 2 is one stage, and the mutual induction voltage signals V1+, V1- output by the coil of 1# in FIG. 1 are cascaded from STAGE1-1 to STAGE1-N in FIG. 3 to obtain the frequency selection point of the first center frequency and the frequency selection point of the second center frequency, and then are corrected through the clock reference module composed of resistors Rc1-1, Rc1-2 and comparator CMP_1 to obtain the output signal Vout1, and then sent to the controller. The mutual induction voltage signals V2+ and V2- output by the coil 2# are passed through the cascade connection from STAGE2-1 to STAGE2-N in Fig. 3 to obtain the frequency selection point of the third center frequency and the frequency selection point of the fourth center frequency, and then are corrected through the clock reference module consisting of resistors Rc2-1, Rc2-2 and comparator CMP_2 to obtain the output signal Vout2, which is then sent to the controller. The clock reference module is a transitional component between the dual frequency selection filter module and the interface of the controller to suppress common mode interference in the circuit.

[0033] The controller can be set to include two working states of the first antenna module and the second antenna module, namely, the first antenna module and the second antenna module are set to be in an asynchronous excitation state, or the first antenna module and the second antenna module are set to be in an asynchronous mutual induction state. This driving method is full-duplex driving.

[0034] In this embodiment, the first antenna module and the second antenna module are set to an asynchronous excitation state or an asynchronous mutual induction state. The controller is configured to control the first antenna module so that the first antenna module is in an excitation state, and after performing a time delay by phase shifting, control the second antenna module so that the second antenna module is in an excitation state, obtain data to be transmitted, convert the data to be transmitted into an excitation signal according to an encoding rule of an extremely low frequency pulse sequence for representing the data to be transmitted and received data based on a symbol envelope and a pulse sequence, transmit the excitation signal to the excitation unit of the first antenna module and the second antenna module to generate an excitation current signal in the coil of the first antenna module and the second antenna module, receive an induction signal, which is a signal generated by induction of the coil of the first antenna module and the second antenna module, by the coil of the first antenna module and the second antenna module, perform clock correction on the induction signal, and analyze the corrected induction signal to obtain the received data. This can realize two-way data transmission.

[0035] In order to better explain the present technical configuration, the concept of a slave station is used in the following description, and the slave station has the same configuration as the master station, and is composed of a controller, a first antenna module, and a second antenna module. The first antenna module of the slave station is 1#, and the second antenna module is 2#. In order to ensure the stability and reliability of the sensing signal and maximize the sensing distance, the 1# of the master station and the 1# of the slave station, and the 2# of the master station and the 2# of the slave station are made as parallel as possible. As shown in FIG. 4, FIG. 4 is a schematic diagram of the communication between the master station and the slave station, and after the controller sends a digital signal, two-way communication between the master station and the slave station can be performed.

[0036] In the master station, the digital signal sent by the controller is converted into two excitation signals, 1# excitation_Vt1+ and 2# excitation_Vt2+. The 1# excitation signal has no voltage change after passing through the voltage follower composed of the operational amplifier U_1. The 2# excitation signal has its logic inverted after passing through the inverting proportional amplifier. Vref is the reference voltage and can be 2.5V. The coil excitation signal between the master station 1# and the slave station 1# and the coil excitation signal between the master station 2# and the slave station 2# are controller-linked (or software-linked), and the mutual exclusion of the read and write states between the master station and the slave station is realized, and the collision between read and write caused by the transmission delay is resolved by increasing the dead band. The excitation time sequence between coil 1# of the master station and coil 2# of the master station and the excitation time sequence between coil 1# of the slave station and coil 2# of the slave station are controlled by phase shift, that is, the excitation enable of coil 2# is controlled by using the switching time point of the frequency of the 1# coil excitation signal.

[0037] FIG. 5 is a schematic diagram of the generation of an extremely low frequency excitation sequence and the identification of a pulse sequence. In order to obtain the phase shift relationship of the circled numbers 1 and 4 in FIG. 5, it is necessary to execute the following phase shift control. Set "master station 1# write W" to the state 1, and change the frequency of "master station 1# write W" from f1 to f2, where f1 and f2 correspond to two frequencies in the frequency band of 1#, for example, f1 is 27Hz and f2 is 30Hz. Set "master station 2# write W" to the state 1, and change the frequency of "master station 2# write W" from f3 to f4, where f3 and f4 correspond to two frequencies in the frequency band of 2#, for example, f3 is 20Hz and f4 is 23Hz. By phase shifting, the transmission and reception frequencies of coils 1# and 2# in the same extremely low frequency (ELF) sensing device can be controlled to always be different, and by having a short excitation overlap time and a magnetic shield outer layer for the coils, the occurrence of co-channel interference by the two coils in the master station can be avoided. The antenna is in a mutual induction state when in a read state, and in an excitation state when in a write state.

[0038] As shown in FIG. 5, the frequency selection point of the first center frequency is reflected in the process of circle number 1 and circle number 4, which is the first half of the period of the write state of the coil 1# of the master station and the coil 2# of the master station in FIG. 5, respectively, and the corresponding frequencies are f1=27Hz and f3=20Hz, respectively. The frequency selection point of the second center frequency is reflected in the process of circle number 2 and circle number 5, which is the second half of the period of the write state of the coil 1# of the master station and the coil 2# of the master station in FIG. 5, respectively, and the corresponding frequencies are f2=30Hz and f4=23Hz, respectively. When each coil works in mutual induction mode, the matching filter modules are also different from each other, specifically reflected in the center frequency and bandwidth of the filter modules. The voltage signals output from the two sets of dual frequency selection filter modules pass through the clock reference module for correction to eliminate the common mode interference in the circuit, and then finally input into the universal input interface of the controller.

[0039] Master station 1# and slave station 1# and master station 2# and slave station 2# need to use two different extremely low frequency (ELF) frequency bands, such as 27-30Hz and 20-23Hz, respectively, and for further distinction, as shown in Figure 5, in the waveform of master station 1#, circle number 1 uses 27Hz, circle number 2 uses 30Hz, and in the waveform of master station 2#, circle number 4 uses 20Hz, and circle number 5 uses 23Hz, so that the overlap area and frequency band difference of excitation between the coil of master station 1# and the coil of master station 2# are maximized, which is favorable for subsequent filtering and processing by the controller.

[0040] The master station and the slave station can be divided into four operating states, master station 1# write W state, slave station 1# write W state, master station 2# write W state, and slave station 2# write W state, according to the order of excitation and mutual induction of each coil of the master station and the slave station. Here, the master station 1# write W state and the slave station 1# write W state realize the interlocking by using a software protocol to ensure that one side between the master station and the slave station is in writing and the other side is in reading state, and the dead zone circle number 3 solves the delay problem when the slave station 1# reads the signal of the master station 1# write W state. The master station 2# write W state and the slave station 2# write W state realize the interlocking by using a software protocol to ensure that one side between the master station and the slave station is in writing and the other side is in reading state, and the dead zone circle number 6 solves the delay problem when the slave station 2# reads the signal of the master station 2# write W state.

[0041] Since the controller can only process digital signals, both the input signal and the output signal are digital signals, and in many cases, the size of the digital signal is expressed by a binary number with a finite number of bits. The encoding rule of the extremely low frequency pulse sequence is set in the controller, and the encoding rule of the extremely low frequency pulse sequence includes a symbol envelope and a pulse sequence, and the symbol envelope includes a leading symbol, a trailing symbol, a dead zone, and a data packet symbol. In FIG. 5, the circled numbers 7 to 10 are waveforms of the symbol envelope, where the circled numbers 7 and 8 are generally defined as the leading symbol and the trailing symbol, the circled number 9 is defined as the dead zone, and the circled number 10 is defined as the data packet symbol. The pulse sequence_PS1 and the pulse sequence_PS2 in FIG. 5 show the difference between the pulses of the symbol envelope in different frequency bands, and in this application, two channels that are actually divided into four frequencies (f1, f2, f3, and f4) are used to correspond to four types of pulse sequences. For the circled numbers 1, 2, 4 and 5 in the figure, any number of symbol envelope periods can be used as necessary, and in this application, at least one set of complete waveforms from circled numbers 7 to 10 is used to read signals between the master station and slave station. Using multiple sets of waveforms can increase the redundancy of extremely low frequency (ELF) magnetic sensing, but also lengthen the sensing period.

[0042] According to the above embodiment, by using full-duplex driving, the coils of the master station 1# and the slave station 1# can read, and the coils of the master station 2# and the slave station 2# can write, that is, the coils of the master station 1# and the slave station 1# are used to alternate between the analysis data or the operating status of the registers of two systems inside and outside the shielded area, and the coils of the master station 2# and the slave station 2# are used to alternate between the commands and responses between the systems, or upload the operating status of other sensors. This can realize simultaneous alternation of various information between the inside and outside of the shielded area.

[0043] An extremely low frequency electromagnetic wave full-duplex magnetic sensing method according to some embodiments of the present application is applied to an extremely low frequency electromagnetic wave full-duplex magnetic sensing device according to the above embodiments, which comprises a controller, a first antenna module, and a second antenna module, and the first antenna module and the second antenna module comprise an antenna body, an excitation unit, and a mutual induction unit. The method includes the steps of controlling the first antenna module so that the first antenna module is in an excited state, performing a time delay by phase shifting, and then controlling the second antenna module so that the second antenna module is in an excited state; acquiring data to be transmitted; converting the data to be transmitted into an excitation signal according to an encoding rule of an extremely low frequency pulse sequence for representing the data to be transmitted and the received data based on a symbol envelope and a pulse sequence; transmitting the excitation signal to the excitation units of the first antenna module and the second antenna module to generate excitation current signals in the coils of the first antenna module and the second antenna module; receiving an induced signal, which is a signal generated by induction of the coils of the first antenna module and the second antenna module by the coils of the first antenna module and the second antenna module; performing clock correction on the induced signal; and analyzing the corrected induced signal to acquire the received data.

[0044] According to the above embodiment, the present application provides an extremely low frequency electromagnetic wave full-duplex magnetic sensing device and method, the device includes a controller, a first antenna module, and a second antenna module, the first antenna module and the second antenna module include an excitation unit, a mutual induction unit, a coil, a magnetic core, and a shield layer. MagneticThe core is provided inside the coil, and the coil is provided inside the shield layer. The excitation unit and the mutual induction unit are respectively connected to the coil. The controller is connected to the first antenna module and the second antenna module. The controller controls the first antenna module and the second antenna module so that the first antenna module and the second antenna module are in an asynchronous excitation state or an asynchronous mutual induction state, acquires data to be transmitted and converts it into an excitation signal, transmits the excitation signal to the excitation units of the first antenna module and the second antenna module to generate an excitation current signal in the coils of the first antenna module and the second antenna module, receives an induction signal that is a signal generated by induction of the coils of the first antenna module and the second antenna module by the coils of the first antenna module and the second antenna module, performs clock correction on the induction signal, and analyzes the corrected induction signal to acquire received data. By using the above method, the extremely low frequency electromagnetic wave full-duplex magnetic sensing device can simultaneously perform two-way transmission of data, complete real-time magnetic sensing alternation of various information, and be applied to two-way communication between inside and outside in a shielded area, thereby improving the quality and speed of data transmission.

[0045] Similar parts between the embodiments of the present application can be mutually referenced, and the specific embodiments mentioned above are merely some examples based on the general idea of ​​the present application, and do not limit the scope of protection of the present application. Those skilled in the art can understand that all other embodiments obtained without creative efforts based on the technical configuration of the present application also belong to the scope of protection of the present application.

Claims

1. An extremely low frequency electromagnetic wave full duplex magnetic sensing device, A controller, a first antenna module, and a second antenna module, The first antenna module and the second antenna module each include an excitation unit, a mutual induction unit, a coil, a magnetic core, and a shield layer; The magnetic core is provided inside the coil, The coil is provided inside the shield layer, the excitation unit and the mutual induction unit are connected to the coil such that the first antenna module and the second antenna module are in an excited state and a mutual induction state; The controller is connected to the excitation unit of the first antenna module and the excitation unit of the second antenna module; The controller: Controlling the first antenna module so that the first antenna module is in an excited state, and after performing a time delay by phase shifting, controlling the second antenna module so that the second antenna module is in an excited state; Get the data waiting to be sent, converting the data to be transmitted into an excitation signal according to an encoding rule of an extremely low frequency pulse sequence for representing the data to be transmitted and the received data based on a symbol envelope and a pulse sequence; Sending the excitation signal to the excitation unit of the first antenna module and the excitation unit of the second antenna module to generate an excitation current signal in the coil of the first antenna module and the coil of the second antenna module; receiving an induced signal generated by induction between the coil of the first antenna module and the coil of the second antenna module by the coil of the first antenna module and the coil of the second antenna module; performing a clock correction on the guided signal; Analyzing the corrected induced signal using the coding rule of the extremely low frequency pulse sequence to obtain received data. An extremely low frequency electromagnetic wave full-duplex magnetic sensing device characterized by being configured as follows.

2. 2. The extremely low frequency electromagnetic wave full-duplex magnetic sensing device according to claim 1, wherein the symbol envelope includes a leading symbol, a trailing symbol, a dead zone and a data packet symbol.

3. The controller further comprises: Setting the first antenna module and the second antenna module to be in an asynchronous excitation state; Alternatively, the first antenna module and the second antenna module are set to be in an asynchronous mutual induction state.

2. The extremely low frequency electromagnetic wave full-duplex magnetic sensing device according to claim 1, characterized in that it is configured as follows.

4. Further comprising an excitation current detection module and an analog-to-digital conversion module; The coil of the first antenna module and the coil of the second antenna module are respectively connected to a controller through the excitation current detection module and the analog-to-digital conversion module in sequence; The controller: Obtain the excitation current and a preset current threshold; When the excitation current is equal to or greater than a current threshold, the excitation unit is controlled to stop generating an excitation current signal.

2. The extremely low frequency electromagnetic wave full-duplex magnetic sensing device according to claim 1, characterized in that it is configured as follows.

5. The extremely low frequency electromagnetic wave full-duplex magnetic sensing device of claim 1, characterized in that the first antenna module and the second antenna module further comprise a magnetic reset diode connected in parallel with the coil for completing a magnetic reset when the coil is switched between an excited state and a mutual induction state.

6. a dual frequency selective filter module and a clock reference module; The extremely low frequency electromagnetic wave full-duplex magnetic sensing device of claim 1, wherein the mutual induction unit of the first antenna module and the mutual induction unit of the second antenna module are connected to the controller through the dual frequency selective filter module and the clock reference module in sequence.

7. The dual frequency selective filter module comprises a first antenna module filter module and a second antenna module filter module; The first antenna module filter module is for arranging a first mutual induction frequency band in the first antenna module, and includes a frequency selection point of a first center frequency and a frequency selection point of a second center frequency; The extremely low frequency electromagnetic wave full-duplex magnetic sensing device of claim 6, characterized in that the second antenna module filter module is for arranging a second mutual induction frequency band in the second antenna module, and includes a frequency selection point of a third center frequency and a frequency selection point of a fourth center frequency.

8. The first antenna module and the second antenna module further include a PMOS transistor and an NMOS transistor; the PMOS transistor, the NMOS transistor, and the coil form a half-bridge excitation circuit; 2. The extremely low frequency electromagnetic wave full-duplex magnetic sensing device according to claim 1, wherein the PMOS transistor and the NMOS transistor are for controlling the coil.

9. 2 . The extremely low frequency electromagnetic wave full-duplex magnetic sensing device according to claim 1 , wherein the coil of the first antenna module and the coil of the second antenna module have central axes perpendicular to each other.

10. A method for extremely low frequency electromagnetic wave full duplex magnetic sensing, comprising: Any of claims 1 to 9 is applied to the extremely low frequency electromagnetic wave full-duplex magnetic sensing device according to claim 1, comprising a controller, a first antenna module, and a second antenna module; The first antenna module and the second antenna module each include an excitation unit, a mutual induction unit, a coil, a magnetic core, and a shield layer; The extremely low frequency electromagnetic wave full duplex magnetic sensing method includes: controlling the first antenna module to be in an excited state, and after performing a time delay by phase shifting, controlling the second antenna module to be in an excited state; obtaining pending data; converting the data to be transmitted into an excitation signal according to an encoding rule of an extremely low frequency pulse sequence for representing the data to be transmitted and the received data based on a symbol envelope and a pulse sequence; Sending the excitation signal to the excitation units of the first antenna module and the second antenna module to generate excitation current signals in the coils of the first antenna module and the second antenna module; receiving an induced signal generated by induction of the coils of the first antenna module and the second antenna module by the coils of the first antenna module and the second antenna module; performing a clock correction on the guided signal; and analyzing the corrected induced signal using the encoding rule of the extremely low frequency pulse sequence to obtain received data.

Images