An alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials

Abstract

The present invention provides an alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials, which relates to the field of electromagnetic technology and includes a five-axis magnetic field radiation antenna group, an excitation voltage generating unit, an induced voltage receiving unit, a current integration control unit, a magnetic field measurement unit, and a magnetic field control unit; the five-axis magnetic field radiation antenna group is composed of a central antenna and four surrounding antennas evenly surrounding it and forming the same angle with it. Each antenna is composed of a soft magnetic material core and an antenna coil, and is used to form an alternating magnetic field whose radiation direction can be adjusted by the excitation voltage; the induced voltage receiving unit adjusts the induced voltage generated by the magnetic field receiving coil and jointly provides radiation energy with the excitation voltage generating unit; the magnetic field measurement unit measures the radiation magnetic field, and the magnetic field control unit continuously adjusts the direction, frequency, and intensity of the radiation magnetic field. The present invention can meet the requirements of quickly and accurately changing the magnetic field state.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic technology, and particularly to an alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials. Background Art

[0002] Low-frequency electromagnetic detection is a technology for detecting the characteristics of objects or environments through low-frequency electromagnetic waves. The frequency of low-frequency electromagnetic waves is generally between dozens of hertz and hundreds of thousands of hertz. Compared with high-frequency electromagnetic waves, low-frequency electromagnetic waves have stronger penetration ability and can penetrate the ground, water bodies or other obstacles. Therefore, they are widely used in the field of electromagnetic detection.

[0003] The radiation of low-frequency electromagnetic waves is mainly achieved by generating an alternating magnetic field. Currently, methods for generating low-frequency alternating magnetic fields include energized solenoids and permanent magnet type mechanical antennas, etc. Among them, the alternating magnetic field generated by an energized solenoid is very weak and difficult to meet the detection requirements. The magnetic field generated by a permanent magnet type mechanical antenna is stronger, but due to mechanical drive, its stability and flexibility are relatively low.

[0004] In low-frequency electromagnetic detection, it may be necessary to scan multiple directions in the area ahead. Currently, the generally used magnetic field generating devices with adjustable direction only adjust the magnetic field vector direction in a small working area and do not consider the problem of magnetic field radiation direction. Summary of the Invention

[0005] Aiming at the above problems, the present invention provides an alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials, which simultaneously solves the problems of insufficient magnetic field strength, low stability, poor directivity and low flexibility.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] An alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials, comprising a five-axis magnetic field radiation antenna group, an excitation voltage generating unit, an induced voltage receiving unit, a current integration control unit, a magnetic field measurement unit, and a magnetic field control unit; the five-axis magnetic field radiation antenna group consists of a central antenna and four surrounding antennas evenly surrounding the central antenna and forming the same angle with the central antenna. Each central antenna and surrounding antenna is composed of a soft magnetic material core and an antenna coil. After each antenna coil is excited by the excitation voltage generating unit, an alternating magnetic dipole field is generated. The alternating magnetic fields are vectorially superimposed in space to form an alternating magnetic field whose radiation direction can be adjusted by the excitation voltage; the magnetic field receiving coil converts the alternating magnetic field opposite to the radiation direction into an induced voltage, and the induced voltage receiving unit adjusts the induced voltage. Through the dynamic regulation of the current integration control unit, it jointly provides radiation energy with the excitation voltage generating unit; the magnetic field measurement unit measures the radiation magnetic field, and the magnetic field control unit continuously adjusts the direction, frequency, and intensity of the radiation magnetic field.

[0008] Beneficial effects:

[0009] The present invention can continuously generate a composite alternating magnetic field in a specified direction in the front half space of the device. The frequency of the generated composite magnetic field can be continuously adjusted in the range of 0 to 100 kHz. In the case of the same volume, the radiation magnetic field intensity can reach 1 / 3 of that of a neodymium iron boron magnet. The switching speed of different frequencies, intensities, and directions can reach the millisecond level, and it has high stability, which can meet the requirements of quickly changing the radiation frequency, intensity, and direction of the alternating magnetic field in low-frequency electromagnetic detection. Description of the drawings

[0010] Figure 1 It is a schematic structural diagram of the alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to the embodiment of the present invention;

[0011] Figure 2 It is a functional principle block diagram of the alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to the embodiment of the present invention.

[0012] Among them, the reference numerals are: the first-axis magnetic field radiation antenna group 1-1, the second-axis magnetic field radiation antenna group 1-2, the third-axis magnetic field radiation antenna group 1-3, the fourth-axis magnetic field radiation antenna group 1-4, the fifth-axis magnetic field radiation antenna group 1-5, the first measurement coil 7-1, the second measurement coil 7-2, the third measurement coil 7-3, the fourth measurement coil 7-4, the fifth measurement coil 7-5, the receiving plate 8, the first receiving coil 9-1, the second receiving coil 9-2, the third receiving coil 9-3, the fourth receiving coil 9-4, the fifth receiving coil 9-5, the sixth receiving coil 9-6, the seventh receiving coil 9-7, the eighth receiving coil 9-8, the ninth receiving coil 9-9, the housing 10. Detailed implementation mode

[0013] In order to make the specific structure, technical solution and advantages of the present invention clearer, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0014] As Figure 1 , Figure 2 shown, an alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to an embodiment of the present invention, divided by function, includes a five-axis magnetic field radiation antenna group, an excitation voltage generating unit, an induced voltage receiving unit, a current integration control unit, a magnetic field measurement unit and a magnetic field control unit.

[0015] The five-axis magnetic field radiation antenna group includes a first-axis magnetic field radiation antenna group 1-1, a second-axis magnetic field radiation antenna group 1-2, a third-axis magnetic field radiation antenna group 1-3, a fourth-axis magnetic field radiation antenna group 1-4, and a fifth-axis magnetic field radiation antenna group 1-5, that is, it consists of a central antenna (the first-axis magnetic field radiation antenna group 1-1) and four surrounding antennas evenly surrounding it and forming the same angle with the same end of the central antenna. Each antenna consists of a soft magnetic material core and an antenna coil, forming an antenna array.

[0016] The excitation voltage generating unit generates five alternating voltages with the same frequency and phase. After each antenna coil of the five-axis magnetic field radiation antenna group is excited by the alternating voltage (that is, the excitation voltage in Figure 2 ), an alternating magnetic dipole field is generated. This magnetic dipole field is enhanced under the magnetization of the soft magnetic material core. The magnetic fields generated by the five antennas are vectorially superimposed in three-dimensional space to form an alternating magnetic field whose radiation direction can be adjusted by the amplitudes of the five excitation voltages.

[0017] The induced voltage receiving unit converts the alternating magnetic field opposite to the radiation direction into an induced voltage through a magnetic field receiving coil located behind the alternating magnetic field generating device, and jointly provides radiation energy with the excitation voltage generating unit through the dynamic regulation of the current integration control unit.

[0018] The magnetic field measurement unit can measure the radiation magnetic field through a magnetic field measurement coil. The magnetic field control unit can issue the required current signal to the current integration control unit according to the measurement result, and then continuously adjust the direction, frequency and intensity of the radiation magnetic field, which can meet the requirement of quickly and accurately changing the magnetic field state.

[0019] Furthermore, the shape of the soft magnetic material core of each axis magnetic field radiation antenna of the five-axis magnetic field radiation antenna group is cylindrical, placed in a cylindrical antenna coil skeleton, the antenna coil is wound around the antenna coil skeleton, and the periphery of the antenna coil is wrapped by a cylindrical protective shell.

[0020] Furthermore, the central antenna is along the positive Z-axis direction, and the other four surrounding antennas are evenly distributed in the XZ plane and the YZ plane. The angles between all the surrounding antennas and the positive Z-axis direction are the same. The distances from the bottoms of all the antennas to the coordinate origin are the same, and the winding methods of all the antennas are the same.

[0021] Furthermore, the magnetic field receiving coils are placed on the receiving plate 8 in the shape of a half ellipsoid. The areas of each magnetic field receiving coil are approximately the same, and the entire receiving plate is covered without gaps between the magnetic field receiving coils.

[0022] Furthermore, the center of the ellipsoidal receiving plate 8 coincides with the coordinate origin and is entirely below the XY plane. The semi-axis length in the X-axis direction of the ellipsoid is equal to the semi-axis length in the Y-axis direction.

[0023] Furthermore, the magnetic field measuring coils of the magnetic field measuring unit are respectively located at the ends of the five-axis magnetic field radiation antenna group far from the coordinate origin, coaxial with each antenna and having a certain distance, and are surrounded by a protective shell.

[0024] Furthermore, the excitation voltage generating unit, the induced voltage receiving unit, the current integration control unit, the magnetic field measuring unit, and the magnetic field control unit are all located behind the ellipsoidal receiving plate, and all the modules are fixed by a support structure.

[0025] Furthermore, the soft magnetic material core is a soft magnetic material with high magnetic permeability and high resistivity. The cylindrical antenna coil skeleton, the protective shell of the antenna coil, the ellipsoidal receiving plate 8, and all the support structures are non-metallic materials with low magnetic permeability (μ r ≈1) and high hardness.

[0026] The control parts of the magnetic field control unit, the current integration control unit, and other units are all programmable controlled by a micro control unit (MCU).

[0027] As Figure 2 shown, the magnetic field control unit calculates the effective value of the current that each antenna coil should reach according to the input desired magnetic field strength, direction, and frequency. Due to the non-linearity of the magnetic permeability of the soft magnetic material, in order to make the alternating magnetic field radiated by the antenna be sinusoidal and have no high-frequency components, according to the B-H curve and hysteresis characteristics of the used core material, the specific current waveform of each antenna coil in one cycle is calculated and transmitted to the current integration control unit.

[0028] Furthermore, the magnetic field control unit receives in real time the actual magnetic field waveform measured by the magnetic field measuring unit (i.e., Figure 2 the measured radiation magnetic field waveform in

[0029] The current integration control unit receives the current frequencies of five antenna coils sent by the magnetic field control unit, as well as the current change waveforms of each antenna coil within one period, and converts them into voltage change waveforms within one period according to the impedance characteristics of the antenna coils, and transmits the desired excitation voltage waveform to the excitation voltage generation unit.

[0030] Further, the current integration control unit monitors in real time the current waveforms of the antenna coils (i.e., Figure 2 the measured antenna coil current waveforms), and dynamically adjusts the desired excitation voltage waveform transmitted to the excitation voltage generation unit as a feedback signal.

[0031] The excitation voltage generation unit includes a signal generation module, a digital-to-analog conversion module, a power amplification module, a filtering module, and an output isolation module.

[0032] Further, the signal generation module is implemented by an MCU, stores the waveform samples to be output in a RAM or Flash, and the MCU reads the stored data and transmits it to the digital-to-analog conversion module to achieve the generation of arbitrary waveforms.

[0033] Further, the digital-to-analog conversion module is implemented by a resistor-divider (R-2R) DAC, and converts the input digital signal into an analog voltage signal through a series of precise resistors.

[0034] Further, the power amplification module is implemented by a power amplifier, amplifies the generated low-amplitude signal to the required voltage and power range, and is suitable for driving a load.

[0035] Further, the filtering module is implemented by a high-order low-pass filter, removes high-frequency noise and harmonic components in the signal, and ensures the purity of the output waveform frequency.

[0036] Further, the output isolation module is implemented by a low-power voltage follower, and its characteristics of high input impedance and low output impedance make the output voltage waveform stable, avoid voltage fluctuations caused by load changes, and effectively isolate the mutual influence between the load and the signal source.

[0037] The output end of each magnetic field receiving coil of the magnetic field receiving coil is connected to a digital potentiometer, whose resistance value range can be adjusted within a certain range, and a low-power operational amplifier voltage follower is connected across the digital potentiometer, and the outputs of the voltage followers of all magnetic field receiving coils are connected in series to combine the induced voltages of the magnetic field receiving coils.

[0038] Further, the resistance value of each of the digital potentiometers is regulated by the current integration control unit. When the resistance value of the digital potentiometer of a certain magnetic field receiving coil is 0, the input of the voltage follower is 0, and all the induced voltages of this magnetic field receiving coil are used to generate an induced current. According to Lenz's law, a magnetic field opposite to the direction of the antenna radiation magnetic field is generated, weakening the alternating magnetic field intensity behind the radiation direction and improving the directivity of the radiation magnetic field.

[0039] Further, when the resistance value of the digital potentiometer of a certain magnetic field receiving coil is +∞, the input of the voltage follower is all the induced voltages generated by this magnetic field receiving coil. When the resistance value of the digital potentiometer of a certain magnetic field receiving coil is between 0 and +∞, its resistance value determines the energy distribution of the two groups of actions.

[0040] Further, the induced voltage receiving unit includes a phase adjustment module, a filtering module, and an output isolation module. The phase adjustment module is implemented by a digital phase shifter and is controlled by the MCU. It adjusts the phase of the combined induced voltage to be the same as the phase of the excitation voltage. The filtering module and the output isolation module are similar to the excitation voltage generation unit.

[0041] Further, the current integration control unit monitors in real time the waveform of the induced voltage adjusted by the induced voltage receiving unit (i.e., Figure 2 the measured induced voltage waveform), and connects the phase-adjusted induced voltage to the antenna coil with the largest voltage demand through a digital switching circuit to supplement energy for the excitation voltage generation unit of this antenna coil.

[0042] Further, the current integration control unit subtracts the voltage waveform required by the antenna coil with the largest voltage demand in one cycle from the waveform of the induced voltage adjusted by the induced voltage receiving unit, and corrects the voltage waveform that the excitation voltage generation unit of this antenna coil needs to generate. That is, the energy of the antenna coil with the largest voltage demand is provided jointly by the induced voltage receiving unit and the excitation voltage generation unit.

[0043] Embodiment:

[0044] A variable radiation direction alternating magnetic field generating device based on soft magnetic materials according to an embodiment of the present invention, divided by structure, as Figure 1 shown, includes a five-axis magnetic field radiation antenna group, an excitation voltage generation unit, an induced voltage receiving unit, a current integration control unit, a magnetic field measurement unit, a magnetic field control unit, a magnetic field measurement coil, a receiving board 8, a magnetic field receiving coil, and a housing 10.

[0045] Each radiation antenna of the five-axis magnetic field radiation antenna group includes a soft magnetic material core and an antenna coil. The soft magnetic material core is made of high-permeability manganese-zinc ferrite material, with a diameter of 30 mm and a length of 200 mm. The inner diameter of the antenna coil skeleton is 30 mm, the thickness of the antenna coil in the radial direction is 10 mm, and the diameter of the cylindrical protective shell is 50 mm. All antennas have the same size and the same winding method. The central antenna is along the positive direction of the Z axis, and all the surrounding antennas are evenly distributed in the XZ plane and the YZ plane. The angle between all the surrounding antennas and the positive direction of the Z axis is 60°, and the distance between all antennas and the coordinate origin is 45 mm.

[0046] The magnetic field receiving coil is composed of 9 receiving coils. Figure 1 As shown in, there are 9 coils, namely the 1st receiving coil 9-1, the 2nd receiving coil 9-2, the 3rd receiving coil 9-3, the 4th receiving coil 9-4, the 5th receiving coil 9-5, the 6th receiving coil 9-6, the 7th receiving coil 9-7, the 8th receiving coil 9-8, and the 9th receiving coil 9-9. One of them is placed at the center of the receiving plate 8, and the remaining 8 are evenly placed in 8 surrounding directions. The area of each magnetic field receiving coil is approximately the same, and the entire receiving plate is covered without gaps between the magnetic field receiving coils. The shape of the receiving plate 8 is a semi-ellipsoid, whose center coincides with the coordinate origin and is entirely below the XY plane. The semi-axis length in the X-axis direction of the ellipsoid is equal to the semi-axis length in the Y-axis direction and is 180 mm, and the semi-axis length in the Z-axis direction of the ellipsoid is 40 mm.

[0047] The magnetic field measuring coil is composed of 5 measuring coils, namely the 1st measuring coil 7-1, the 2nd measuring coil 7-2, the 3rd measuring coil 7-3, the 4th measuring coil 7-4, and the 5th measuring coil 7-5, which are respectively located at the ends of 5 antennas far from the coordinate origin, coaxial with the respective antennas and at a distance of 10 mm. The wire diameter of the enameled wire used for all the magnetic field measuring coils, antenna coils, and magnetic field receiving coils is selected to be 0.5 mm.

[0048] The signal generation, processing, and circuit control part includes signal generation, power amplification, phase adjustment, MCU, etc., which is located behind the receiving plate 8 and fixed on the housing 10 of the generating device. All coils are connected thereto and are regulated by this part.

[0049] The housing of the device, the antenna coil skeleton, the coil protective shell, the ellipsoidal receiving plate, and all the support structures are made of plexiglass material.

[0050] The above structure constitutes six main unit modules, namely the five-axis magnetic field radiation antenna group, the excitation voltage generation unit, the induced voltage reception unit, the current integration control unit, the magnetic field measurement unit, and the magnetic field control unit.

[0051] AsFigure 2 As shown, the magnetic field control unit receives the commands of the desired magnetic field intensity, direction, and frequency sent from the host computer, combines with the magnetic field waveform measured by the magnetic field measurement unit, and calculates the desired current waveforms of all antenna coils.

[0052] The current integration control unit receives the desired current waveforms of the antenna coils sent from the magnetic field control unit, dynamically regulates the antenna coils connected to the induced voltage according to the induced voltage waveform after adjustment by the induced voltage receiving unit and the measured current waveforms of the antenna coils, and calculates the desired excitation voltage waveforms of all antenna coils.

[0053] The excitation voltage generation unit receives the desired excitation voltage waveforms of the antenna coils sent from the current integration control unit, and provides the excitation voltage to the five-axis magnetic field radiation coil group through links such as signal generation, digital-to-analog conversion, power amplification, and filtering.

[0054] The induced voltage receiving unit receives the phase information from the excitation voltage generation unit, and after processes such as phase adjustment and filtering on the induced voltage generated by the magnetic field receiving coil, provides energy for the antenna coil with the largest voltage demand.

[0055] The magnetic field control unit and the current integration control unit are controlled by two levels of forward calculation and error feedback. Taking the magnetic field control unit as an example, when the input desired magnetic field intensity, direction, and frequency change, first calculate the desired current waveforms of each antenna coil through the B-H curve and hysteresis characteristics of the manganese-zinc ferrite, and then adjust the output result using a PID controller according to the error between the measured radiation magnetic field waveform and the ideal sine waveform. By measuring the radiation magnetic field waveform and the current waveforms of the antenna coils to form two-level feedback control, the magnetic field can be controlled with a faster convergence speed.

[0056] The alternating magnetic field generating device with adjustable radiation direction in this embodiment uses high-permeability manganese-zinc ferrite as the antenna magnetic core, and can radiate a stronger magnetic field; using the method of antenna coils and current control can improve the stability of the radiation magnetic field; using the five-axis magnetic field radiation antenna group to radiate a composite magnetic field can make the radiation magnetic field have a higher directivity; using the two-level feedback control method can improve the flexibility of the radiation magnetic field.

[0057] Therefore, overall, the present invention simultaneously meets the requirements of high intensity, high stability, high directivity, and high flexibility of the radiation magnetic field, can continuously, accurately, and quickly adjust the radiation magnetic field, and can meet the demand for quickly changing the radiation direction of the alternating magnetic field in low-frequency electromagnetic detection.

Claims

1. An alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials, characterized in that, It includes a five-axis magnetic field radiation antenna group, an excitation voltage generation unit, an induced voltage reception unit, a current integration control unit, a magnetic field measurement unit, and a magnetic field control unit; the five-axis magnetic field radiation antenna group consists of a central antenna and four surrounding antennas evenly surrounding the central antenna and forming the same angle with the central antenna. Each central antenna and surrounding antenna is composed of a soft magnetic material core and an antenna coil. After each antenna coil is excited by the excitation voltage generation unit, an alternating magnetic dipole field is generated. The alternating magnetic fields are vectorially superimposed in space to form an alternating magnetic field whose radiation direction can be adjusted by the excitation voltage; the magnetic field receiving coil converts the alternating magnetic field opposite to the radiation direction into an induced voltage. The induced voltage reception unit adjusts this induced voltage. Through the dynamic regulation of the current integration control unit, it jointly provides radiation energy with the excitation voltage generation unit; the magnetic field measurement unit measures the radiation magnetic field, and the magnetic field control unit continuously adjusts the direction, frequency, and intensity of the radiation magnetic field; The output terminal of each magnetic field receiving coil is connected to a digital potentiometer, and its resistance value range can be adjusted within a certain range; The resistance value of each digital potentiometer is regulated by the current integration control unit. When the resistance value of the digital potentiometer of a certain magnetic field receiving coil is 0, the input of its low-power operational amplifier voltage follower is 0, and all the induced voltage of this magnetic field receiving coil is used to generate an induced current, thereby generating a magnetic field opposite to the direction of the antenna radiation magnetic field, weakening the intensity of the alternating magnetic field behind the radiation direction, and improving the directivity of the radiation magnetic field; when the resistance value of the digital potentiometer of a certain magnetic field receiving coil is +∞, the input of its low-power operational amplifier voltage follower is all the induced voltage generated by this magnetic field receiving coil. When the resistance value of the digital potentiometer of a certain magnetic field receiving coil is between 0 and +∞, its resistance value determines the energy distribution of the induced current and induced voltage.

2. The alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to claim 1, characterized in that, The shape of the soft magnetic material core of each central antenna and surrounding antenna is cylindrical, placed inside a cylindrical antenna coil skeleton, the antenna coil is wound around the antenna coil skeleton, and the periphery of the antenna coil is wrapped by a cylindrical protective shell.

3. The alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to claim 1, characterized in that, The magnetic field receiving coils are placed on a receiving plate in the shape of a half ellipsoid. The area of each magnetic field receiving coil is the same and covers the entire receiving plate without gaps between the magnetic field receiving coils.

4. The alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to claim 1, wherein The magnetic field measurement coils of the magnetic field measurement unit are respectively located at one end of the five-axis magnetic field radiation antenna group far from the coordinate origin, coaxial with and at a distance from their corresponding antennas.

5. A variable radiation direction alternating magnetic field generating device based on soft magnetic materials according to claim 1, characterized in that, The soft magnetic material core is a soft magnetic material with high magnetic permeability and high resistivity, and the cylindrical antenna coil skeleton, the protective shell of the antenna coil, the receiving plate, and the support structure are non-metallic materials with low magnetic permeability and high hardness.

6. The alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to claim 1, wherein, Both the magnetic field control unit and the current integration control unit are programmable controlled by a micro control unit.

7. A variable radiation direction alternating magnetic field generating device based on soft magnetic materials according to claim 1, characterized in that, The current integration control unit receives the current frequencies of the antenna coils of the central antenna and the surrounding antennas sent by the magnetic field control unit, as well as the current change waveforms of each antenna coil within one cycle, and converts them into voltage change waveforms within one cycle according to the impedance characteristics of the antenna coils, and transmits the desired excitation voltage waveform to the excitation voltage generation unit.

8. The alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to claim 7, characterized in that, The current integration control unit monitors the current waveforms of the antenna coils in real time and dynamically adjusts the desired excitation voltage waveform transmitted to the excitation voltage generation unit as a feedback signal.

9. The alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to claim 1, wherein, The excitation voltage generation unit includes a signal generation module, a digital-to-analog conversion module, a power amplification module, a filtering module, and an output isolation module; The signal generation module is implemented by an MCU, stores the waveform samples to be output in RAM or Flash, and the MCU reads the stored data and transmits it to the digital-to-analog conversion module to generate any waveform; The digital-to-analog conversion module is implemented by a resistive voltage divider DAC, which converts the input digital signal into an analog voltage signal; The power amplification module is implemented by a power amplifier, which amplifies the generated low-amplitude signal to the required voltage and power range for driving the load; The filtering module is implemented by a high-order low-pass filter, which removes the high-frequency noise and harmonic components in the signal to ensure the purity of the output waveform frequency; The output isolation module is implemented by a low-power voltage follower, and its characteristics of high input impedance and low output impedance make the output voltage waveform stable.

10. The alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to claim 1, characterized in that, Both ends of the digital potentiometer are connected to a low-power operational amplifier voltage follower, and the outputs of the low-power operational amplifier voltage followers of all magnetic field receiving coils are connected in series to combine the induced voltages of the magnetic field receiving coils.

11. A variable radiation direction alternating magnetic field generating device based on soft magnetic materials according to claim 1, characterized in that, The induced voltage receiving unit includes a phase adjustment module, a filtering module, and an output isolation module. The phase adjustment module is implemented by a digital phase shifter and is controlled by the MCU, which adjusts the phase of the combined induced voltage to be the same as the phase of the excitation voltage.

12. The alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to claim 1, characterized in that, The current integration control unit monitors the induced voltage waveform adjusted by the induced voltage receiving unit in real time, and connects the phase-adjusted induced voltage to the antenna coil with the largest voltage demand through a digital switching circuit to supplement energy for the excitation voltage generation unit of this antenna coil.

13. The alternating magnetic field generating device with adjustable radiation direction based on soft magnetic materials according to claim 1, characterized in that, The current integration control unit subtracts the voltage waveform required by the antenna coil with the largest voltage demand within one cycle from the induced voltage waveform adjusted by the induced voltage receiving unit, and corrects the voltage waveform that the excitation voltage generation unit of this antenna coil needs to generate, that is, the energy of the antenna coil with the largest voltage demand is provided jointly by the induced voltage receiving unit and the excitation voltage generation unit.

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