CN115079069A - Frequency-variable modulation field system, control method thereof and EPR spectrometer - Google Patents
Frequency-variable modulation field system, control method thereof and EPR spectrometer Download PDFInfo
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- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
- G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
- G01R33/36—Electrical details, e.g. matching or coupling of the coil to the receiver
- G01R33/3607—RF waveform generators, e.g. frequency generators, amplitude-, frequency- or phase modulators or shifters, pulse programmers, digital to analog converters for the RF signal, means for filtering or attenuating of the RF signal
Abstract
The invention discloses a frequency-variable modulation field system, a control method and an EPR spectrometer with the frequency-variable modulation field system, wherein the frequency-variable modulation field system comprises: a driver for providing an alternating current signal of a target frequency; a resonant circuit comprising a capacitive array and a modulation field coil, a first end of the capacitive array being connected to the driver and a second end of the capacitive array being connected to the modulation field coil, the modulation field coil being for providing a modulated magnetic field to the EPR probe; the current monitoring device is connected with the resonant circuit and used for monitoring the current in the resonant circuit; and the controller is respectively connected with the capacitor array and the current monitoring device and is used for adjusting the capacitance value of the capacitor array according to the current so as to enable the resonant circuit to be in a resonant state. The system can realize the adjustment of the frequency of the modulation field.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to a frequency-variable modulation field system, a control method thereof and an EPR spectrometer.
Background
At present, for an EPR (Electron Paramagnetic Resonance Spectroscopy) modulation field, a phase-sensitive detection technology is usually used to improve the signal-to-noise ratio of an EPR spectral line. Specifically, a modulated magnetic field having a frequency of 100kHz is realized by winding helmholtz coils on both sides of the cavity along the axis of the static magnetic field, but for a spectrum having a relaxation time of 10us (100 kHz is equivalent to 10 us) or longer, the frequency of the modulated field must be less than 100kHz, otherwise an accurate spectrum of the sample may not be measured. Furthermore, a modulation field superimposed on the microwave frequency causes broadening, a modulation field of 100kHz corresponds to a 35mG broadening, which produces sidebands in the EPR spectrum. In a spectral line several hundred mG wide, this sideband is not observed. However, for samples with narrow linewidth or very small hyperfine coupling constant, the modulation sidebands distort the lineshape, and the modulation frequency needs to be reduced.
However, the above-described phase-sensitive detection technique can only discriminate the phase of the modulation signal and select the frequency, and cannot adjust the frequency of the modulation field.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, it is an object of the invention to propose a frequency-variable modulation field system which allows an adjustment of the modulation field frequency.
A second object of the invention is to propose an EPR spectrometer.
A third object of the present invention is to provide a method for controlling a frequency-variable modulation field system.
In order to achieve the above object, a first aspect of an embodiment of the present invention provides a frequency-variable modulation field system, which includes: a driver for providing an alternating current signal of a target frequency; a resonant circuit comprising a capacitive array and a modulation field coil, a first end of the capacitive array being connected to the driver and a second end of the capacitive array being connected to the modulation field coil, the modulation field coil being for providing a modulated magnetic field to the EPR probe; the current monitoring device is connected with the resonant circuit and is used for monitoring the current in the resonant circuit; and the controller is respectively connected with the capacitor array and the current monitoring device and is used for adjusting the capacitance value of the capacitor array according to the current so as to enable the resonant circuit to be in a resonant state.
In order to achieve the above object, a second aspect of the embodiments of the present invention provides an EPR spectrometer, including: an EPR probe, a frequency variable modulation field system as described in the embodiments of the first aspect of the present invention.
To achieve the above object, a third aspect of the embodiments of the present invention provides a method for controlling a frequency-variable modulation field system, the frequency-variable modulation field system including a driver and a resonant circuit, the driver being configured to provide an ac signal at a target frequency, the resonant circuit including a capacitor array and a modulation field coil, a first end of the capacitor array being connected to the driver, a second end of the capacitor array being connected to the modulation field coil, the modulation field coil being configured to provide a modulated magnetic field for an EPR probe, the method including: acquiring current in the resonant circuit; and adjusting the capacitance value of the capacitor array according to the current so as to enable the resonant circuit to be in a resonant state.
According to the frequency-variable modulation field system, the control method thereof and the EPR spectrometer, in the frequency-variable modulation field system, the resonant circuit comprises the capacitor array and the modulation field coil, the alternating current signal with the target frequency is provided for the resonant circuit through the driver, the current in the resonant circuit is monitored by the current monitoring device, and meanwhile, the controller is respectively connected with the capacitor array and the current monitoring device in the resonant circuit, so that the capacitance value of the capacitor array can be adjusted according to the current in the resonant circuit, the resonant circuit is in a resonant state, the modulation field coil in the resonant circuit can normally work, the modulation field with the target frequency is provided for the EPR probe, and the frequency of the modulation field with the fixed frequency is adjusted.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a schematic diagram of the structure of a variable frequency modulation field system according to one embodiment of the present invention;
FIG. 2 is a schematic diagram of the structure of a capacitor array according to an example of the present invention;
FIG. 3 is a schematic diagram of the structure of a variable frequency modulation field system according to one embodiment of the present invention;
FIG. 4 is a flow chart of a process for adjusting the capacitance value of a capacitive array according to one embodiment of the invention;
FIG. 5 is a flow chart of a process for adjusting the capacitance value of a capacitor array according to another embodiment of the present invention;
FIG. 6 is a schematic diagram of the structure of an EPR spectrometer according to one embodiment of the present invention;
fig. 7 is a flow chart of a control method of a frequency variable modulation field system according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The variable frequency modulation field system, the control method thereof and the EPR spectrometer of the embodiments of the present invention will be described with reference to fig. 1 to 7 and the detailed description thereof.
Fig. 1 is a schematic structural diagram of a frequency-variable modulation field system 1 according to an embodiment of the present invention. As shown in fig. 1, a frequency-variable modulation field system 1 includes: a driver 101 for providing an alternating current signal of a target frequency; a resonant circuit 102 comprising a capacitive array 201 and a modulation field coil 202, a first end of the capacitive array 201 being connected to the driver 101 and a second end of the capacitive array 201 being connected to the modulation field coil 202, the modulation field coil 202 being arranged to provide a modulated magnetic field for the EPR probe 3; a current monitoring device 103 connected to the resonant circuit 102 for monitoring a current in the resonant circuit 102; and the controller 104 is connected with the capacitor array 201 and the current monitoring device 103 respectively and is used for adjusting the capacitance value of the capacitor array 201 according to the current so as to enable the resonant circuit 102 to be in a resonant state.
Optionally, in some embodiments, the current monitoring device 103 may be disposed between the capacitive array 201 of the resonant circuit 102 and the modulation field coil 202.
Specifically, since one end of the capacitor array 201 in the resonant circuit 102 is connected to the driver 101, when receiving a command for changing the frequency, the driver 101 can provide an ac signal corresponding to the target frequency to the resonant circuit 102 connected thereto, so that the current flows through the resonant circuit 102, and the current monitoring device 103 is connected to the resonant circuit 102, so that the current monitoring device 103 can monitor the current in the resonant circuit 102 in real time. In this embodiment, through the respective connection of the controller 104 and the capacitor array 201 and the current monitoring device 103, the controller 104 can adjust the capacitance value of the capacitor array 201 in the resonant circuit 102 according to the current in the resonant circuit 102 monitored by the current monitoring device 103, so that the resonant circuit 102 can be in a resonant state, thereby ensuring that the modulation field coil 202 included in the resonant circuit 102 can provide the modulation magnetic field of the target frequency to the EPR probe 3, and realizing the change of the frequency of the modulation magnetic field.
Further, in some embodiments, the controller 104 may be specifically configured to: when the target frequency changes, or the inductance of the EPR probe 3 changes, the capacitance value of the capacitor array 201 is adjusted according to the current to bring the resonance circuit 102 into a resonance state.
Specifically, when the modulation field frequency needs to be adjusted, that is, the target frequency is changed, or when the inductance of the EPR probe 3 changes due to probe replacement or other factors (for example, probe aging or wear), even if the modulation field frequency does not need to be adjusted at the present moment, the capacitance value of the capacitor array 201 in the resonant circuit 102 needs to be adjusted according to the current in the resonant circuit 102 monitored by the current monitoring device 103, so that the resonant circuit 102 can be in a resonant state, and the modulation field coil 202 therein can work normally.
As a possible implementation manner, fig. 2 is a schematic structural diagram of a capacitor array according to an example of the present invention, and as shown in fig. 2, a capacitor array 201 includes n-1 switched capacitor branches and a short-circuit branch, where n-1 switched capacitor branches are connected in parallel and connected in parallel with the short-circuit branch to form a first parallel point J1 and a second parallel point J2, the first parallel point J1 is connected with the driver 101, and the second parallel point J2 is connected with the modulation field coil 202, where each switched capacitor branch includes a capacitor and a controllable switch connected in series, and the short-circuit branch includes a controllable switch.
It should be understood that since the first parallel point J1 in the present implementation is connected to the driver 101, an ac signal of a target frequency provided by the driver 101 can reach the resonant circuit 102 through the first parallel point, and the controller 104 adjusts the capacitance value of the capacitor array 201 according to the current in the resonant circuit 102. Since the capacitor array 201 in this implementation comprises n-1 switched capacitor branches and short-circuit branches, and each switched capacitor branch comprises a capacitor and a controllable switch connected in series, when an adjustment of the capacitance value of the capacitor array 201 is required, therefore, by switching the controllable switches comprised in the capacitor branches, the on-off state of n-1 switch capacitor branches is controlled, so that the free combination among different capacitors can be realized, so that the freely combined capacitance value can meet the adjustment requirement of the controller 104 on the capacitance value of the capacitor array 201, to ensure that the resonant circuit 102 can be in a resonant state, the capacitor array 201 can be normally discharged, the energy therein is stored in the modulation field coil 202 in the form of magnetic energy, a modulated magnetic field of a target frequency is provided to the EPR probe 3 by the modulation field coil 202 so that the sample in the EPR probe 3 is in the modulated magnetic field generated by operation of the modulation field coil 202.
Optionally, in some embodiments, the controllable switch selects a relay, and the access state of the capacitor in each switched capacitor branch is controlled by the relay.
Further, as shown in fig. 3, in some embodiments of the present invention, the frequency variable modulation field system 1 may further include: and an amplifier 105, the amplifier 105 being connected between the driver 101 and the resonant circuit 102, for amplifying the ac signal.
As a possible implementation manner, as shown in fig. 4, when the controller 104 adjusts the capacitance value of the capacitor array 201 according to the current to make the resonant circuit 102 in the resonant state, the adjusting of the capacitance value of the capacitor array 201 may specifically include the following steps:
s101, determining an initial capacitance value sequence, wherein the initial capacitance value sequence comprises a minimum capacitance value 0 and a maximum capacitance value C which are adjustable by a capacitor array e And initial first, second and third capacitance values, 0 < first capacitance value < second capacitance value < third capacitance value < C e 。
Specifically, a capacitance value set obtained by freely combining the capacitances in each switched capacitor branch can be used as the capacitance value sequence in the embodiment of the present application, and the minimum capacitance value 0 and the maximum capacitance value C in the capacitance value set obtained by free combination are used as the capacitance value sequence in the embodiment of the present application e As the minimum value and the maximum value in the closed interval of the initial capacitance value sequence in the embodiment of the present invention, optionally, in some embodiments, the first capacitance value, the second capacitance value, and the third capacitance value in the initial capacitance value sequence are selected as the pair set [0, C ″ e ]Quartering is carried out to obtain three equal capacitance values, the first capacitance value is less than the second capacitance value and is less than the third capacitance value, and it is understood that in the capacitance value sequence, the first capacitance value is more than 0 and is less than the second capacitance value and is less than the third capacitance value and is less than C e Thus, an initial sequence of capacitance values is obtained.
S102, sequentially adjusting the capacitance value of the capacitor array to the current first capacitance value, second capacitance value and third capacitance value, and obtaining a corresponding first current peak value, a second current peak value and a third current peak value.
Specifically, after the current first capacitance value, the current second capacitance value, and the current third capacitance value are determined, the capacitance value of the capacitor array 201 may sequentially reach the first capacitance value, the current second capacitance value, and the current third capacitance value by controlling a combination manner of capacitors in each switch capacitor branch of the capacitor array 201, and after the current in the resonant circuit 102 monitored by the current monitoring device 103 is stabilized every time of adjustment, the corresponding current peak-to-peak values, that is, the first current peak-to-peak value, the second current peak-to-peak value, and the third current peak-to-peak value, are obtained.
It can be understood that, before obtaining the current peak value, it is necessary to wait for the monitored current to be stable first, during this waiting period, a plurality of different current values may occur, and a value of a difference between a maximum value and a minimum value of the monitored current in this waiting period is determined as the current peak value in the embodiment of the present application, and the current peak value may be used to characterize a magnitude of a current value variation range.
And S103, determining the maximum value of the first current peak-to-peak value, the second current peak-to-peak value and the third current peak-to-peak value, and determining the adjustable capacitance range of the capacitor array according to the maximum value and the current capacitance sequence.
And S104, judging whether the adjustable capacitance range meets a preset segmentation condition.
The preset segmentation condition can be selected according to actual conditions. For example, the preset dividing condition may be determined according to the minimum dividing unit of the array capacitor, for example, the difference between the maximum value and the minimum value in the adjustable capacitance value range determined in S103 is compared with the minimum dividing unit of the array capacitor, and when the difference is less than or equal to the minimum dividing unit, the adjustable capacitance value range is satisfied with the preset dividing condition.
And S105, if so, taking the capacitance value corresponding to the maximum value as a final capacitance value, otherwise, updating the current capacitance value sequence, the first capacitance value, the second capacitance value and the third capacitance value according to the adjustable capacitance value range, and returning to the step of sequentially adjusting the capacitance values of the capacitor array to the current first capacitance value, the current second capacitance value and the current third capacitance value.
That is to say, when the adjustable capacitance range meets the preset segmentation condition, determining a capacitance value corresponding to a maximum value of the first current peak-to-peak value, the second current peak-to-peak value and the third current peak-to-peak value as a final capacitance value; if the adjustable capacitance range does not satisfy the preset segmentation condition, updating the current capacitance sequence, the first capacitance, the second capacitance and the third capacitance according to the adjustable capacitance range, returning to step S102, continuing to adjust the capacitance until the adjustable capacitance range satisfies the preset segmentation condition (for example, a difference between a maximum value and a minimum value in the adjustable capacitance range is less than or equal to a minimum segmentation unit of the array capacitor), and taking the capacitance corresponding to the maximum value in the current peak-to-peak value obtained in the process as a final capacitance.
As a possible implementation manner, the determining the adjustable capacitance value range of the capacitor array 201 according to the maximum value and the current capacitance value sequence in step S103 may include: obtaining a first intermediate capacitance value according to the capacitance value corresponding to the maximum value and the last capacitance value of the capacitance value, obtaining a second intermediate capacitance value according to the capacitance value corresponding to the maximum value and the next capacitance value of the capacitance value, and determining the adjustable capacitance value range of the capacitor array 201 as the range formed by the first intermediate capacitance value and the second intermediate capacitance value.
Specifically, in this implementation manner, after determining the maximum value among the first current peak value, the second current peak value, and the third current peak value in step S103, the middle value between the capacitance value corresponding to the maximum value and the last capacitance value of the capacitance value is found, the middle value is determined as a first middle capacitance value, the middle value between the capacitance value corresponding to the maximum value and the next capacitance value of the capacitance value is found, and the middle value is determined as a second middle capacitance value. In this implementation, through the mode of confirming that the adjustable capacitance value scope is the scope that capacitance value constitutes in the middle of first and the second, constantly dwindle the control range of capacitance value, when guaranteeing to adjust the fineness, still can guarantee to adjust efficiency.
It should be noted that, in some examples, if the capacitance value corresponding to the found maximum value is the first capacitance value in the current capacitance value sequence, the middle value between the adjustable minimum capacitance value 0 of the capacitor array 201 and the first capacitance value is determined as a first middle capacitance value; if the capacitance value corresponding to the found maximum value is the third capacitance value in the current capacitance value sequence, the adjustable maximum capacitance value C of the first capacitance value and the capacitor array 201 is determined e Is a second intermediate capacitance value.
Further, in step S105 of this implementation, when the adjustable capacitance range does not satisfy the preset segmentation condition, updating the current capacitance sequence, the first capacitance, the second capacitance, and the third capacitance according to the adjustable capacitance range may include: and adding the first intermediate capacitance value and the second intermediate capacitance value into the current capacitance value sequence, and updating the current first capacitance value, the current second capacitance value and the current third capacitance value into the capacitance value corresponding to the first intermediate capacitance value and the maximum value and the current second intermediate capacitance value.
Specifically, when it is determined that the adjustable capacitance range (i.e., the range formed by the first intermediate capacitance and the second intermediate capacitance) does not satisfy the preset segmentation condition, the first intermediate capacitance and the second intermediate capacitance need to be added to the current capacitance sequence to update the capacitance sequence, and the first intermediate capacitance is determined as the first capacitance in the updated capacitance sequence, the capacitance corresponding to the maximum value is determined as the second capacitance in the updated capacitance sequence, and the second intermediate capacitance is determined as the third capacitance in the updated capacitance sequence, i.e., the minimum capacitance 0 and the maximum capacitance C of the current capacitance sequence are adjustable by the capacitor array 201 e And the first intermediate capacitance value, the capacitance value corresponding to the maximum value and the second intermediate capacitance value.
In order to explain the implementation of the above implementation more clearly, the implementation is described below by way of an example:
s1, determining the working parameters of the driver, amplifier and EPR probe, and collecting the capacitance value of the array capacitor [0, C e ]In which a capacitance value C of approximately quartering point is selected f1 、C f2 And C f3 。
S2, adjusting the capacitance value of the capacitor array to C f1 、C f2 And C f3 When the current is regulated once, the stable monitoring current is waited to obtain the peak value I of the stable monitoring current f1 、I f2 And I f3 。
S3, finding I f1 、I f2 And I f3 Of (e), e.g. I f3 And at maximum, then: get C f2 And C f3 Middle value of (C) f4 And C f3 And C e Middle value of (C) f5 (ii) a Measuring the peak value I of the corresponding current f4 And I f5 。
S4, finding I f3 、I f4 And I f5 Of, e.g. I f3 Maximum, then: get C f4 And C f3 Middle value of (C) f6 And C f3 And C f5 Middle value of (C) f7 (ii) a Measuring the peak value I of the corresponding current f6 And I f7 。
S5, finding I f3 、I f6 And I f7 Repeating the above steps until the array capacitor is divided into the minimum division unit of the array capacitor, and finding out the capacitance value of the array capacitor corresponding to the maximum value of the current peak value, namely the final capacitance value.
It should be noted that, in some examples of the present invention, when determining the maximum value among the first current peak value, the second current peak value, and the third current peak value according to step S103, a situation that a difference value between the two current peak values is within a preset threshold range, or even equal to the preset threshold range occurs, at this time, the controller 104 may be further configured to take a capacitance value of an approximate quartering point between capacitance values corresponding to the two current peak values to perform monitoring comparison, that is, update the capacitance value sequence to a capacitance value corresponding to the two current peak values and three equant capacitance values obtained by quartering the capacitance value range formed by the capacitance values, and then continue to execute the above implementation manner to determine a final capacitance value. It can be understood that, if this occurs, the adjustment range of the adjustable capacitance will be reduced, and thus the adjustment efficiency can be further improved.
Further, as shown in another embodiment of the present invention, as shown in fig. 5, when the controller 104 adjusts the capacitance value of the capacitor array 201 according to the current to make the resonant circuit 102 in the resonant state, the adjusting of the capacitance value of the capacitor array 201 may specifically include the following steps:
and S201, calculating a target capacitance value according to the target frequency and the inductance value of the EPR probe.
As one example, the target capacitance value is calculated by:
wherein, C s ’ Is the target capacitance, F is the target frequency, and L is the inductance of the EPR probe 3.
S202, finding out a capacitance value C closest to a target capacitance value from a capacitance value sequence consisting of adjustable capacitance values of the capacitor array s And C s Last capacitance value C of s-1 And the next capacitance value C s+1 。
It can be understood that the target capacitance calculated according to the target frequency and the inductance of the EPR probe 3 is a capacitance completely adapted to the target frequency, but in the specific implementation process, if a capacitance consistent with the target capacitance cannot be found in the capacitance sequence composed of the adjustable capacitances of the capacitor array 201, a capacitance C closest to the target capacitance can be found therefrom s According to the capacitance value C s And carrying out subsequent capacitance value adjustment work.
S203, sequentially adjusting the capacitance value of the capacitor array to C s 、C s-1 And C s+1 And obtaining the corresponding current peak value I s 、I s-1 And I s+1 。
S204, judging I s 、I s-1 And I s+1 Maximum value of (2).
S205, if I s At the maximum, then C is added s As the final capacitance value.
S206, if I s-1 At maximum, find C from the capacitance sequence s-1 Last capacitance value C of s-2 And adjusting the capacitance value of the capacitor array to C s-2 Obtaining the corresponding current peak value I s-2 And in I s-2 Is less than I s-1 When it is, C is s-1 As the final capacitance value, otherwise, continuously finding out C s-3 Up to I s-x Is less than I s-x+1 Is shown by s-x+1 Corresponding to C s-x+1 As the final capacitance value.
That is, after judging I s 、I s-1 And I s+1 Has a maximum value of I s-1 Then, C needs to be found out from the capacitance sequence s-1 Last capacitance value C of s-2 And adjusting the capacitance value of the capacitor array 201 to C s-2 Obtaining the corresponding current peak value I s-2 Then mix I s-2 And I s-1 Comparing and judging I s-2 Whether or not less than I s-1 If I is s-2 Is less than I s-1 Then C is added s-1 As a final capacitance value, if I s-2 Greater than or equal to I s-1 Then continue to find C from the capacitance sequence s-2 Last capacitance value C of s-3 And continuing to execute subsequent steps of adjusting and judging the current until the current peak value corresponding to the last capacitance value of the found capacitance values is smaller than the current peak value corresponding to the capacitance value, and taking the capacitance value as the final capacitance value.
S207, if I s+1 At maximum, find C from the capacitance sequence s+1 Next capacitance value C s+2 And adjusting the capacitance value of the capacitor array to C s+2 Obtaining the corresponding current peak value I s+2 And in I s+2 Is less than I s+1 When it is, C is s+1 As the final capacitance value, otherwise, continuously finding out C s+3 Up to I s+x+1 Is less than I s+x Is shown by s+x Corresponding to C s+x As the final capacitance value.
That is, after judging I s 、I s-1 And I s+1 Has a maximum value of I s+1 Then, C needs to be found out from the capacitance sequence s+1 Next capacitance value C of s+2 And adjusting the capacitance value of the capacitor array 201 to C s+2 Obtaining the corresponding current peak value I s+2 Then mix I s+2 And I s+1 Comparing and judging I s+2 Whether or not less than I s+1 If I is s+2 Is less than I s+1 Then C will be s+1 As a final capacitance value, if I s+2 Greater than or equal to I s+1 Then continue to find C from the capacitance sequence s+2 Next capacitance value C s+3 Continuing to perform subsequent conditioning and current determination steps until foundAnd the current peak value corresponding to the next capacitance value of the capacitance values is smaller than the current peak value corresponding to the capacitance value, and the capacitance value is used as the final capacitance value.
According to the modulation field system with the variable frequency, disclosed by the embodiment of the invention, when the frequency of a modulation field needs to be adjusted or the inductance of the EPR probe is changed, the capacitance value of the capacitor array is adjusted according to the current in the resonant circuit, so that the resonant circuit can be in a resonant state, a modulation field coil in the resonant circuit can provide a modulation magnetic field with a target frequency for the EPR probe, the frequency of the modulation field with a fixed frequency can be adjusted, and in the process of adjusting the capacitance value, the adjustment precision can be ensured and the adjustment efficiency can be ensured by continuously reducing the range of the adjustable capacitance value.
Further, an embodiment of the present invention provides an EPR spectrometer, as shown in fig. 6, where the EPR spectrometer 2 includes: an EPR probe 3, a variable frequency modulation field system 1.
Different from the related technology, the EPR spectrometer provided by the embodiment of the invention can adjust the frequency of the modulation field with fixed frequency, so that the range of the detection sample is further expanded, the specific modulation field frequency can be selected for samples with different spectral line widths in practical application, and the accuracy of the detection result is high.
In addition, it should be noted that other configurations and functions of the EPR spectrometer according to the embodiments of the present invention are known to those skilled in the art, and are not described herein in detail to reduce redundancy.
In order to implement the above embodiments, the embodiment of the present invention further provides a control method for a frequency-variable modulation field system. Wherein, the variable modulation field system of frequency includes driver and resonant circuit, and the driver is used for providing the alternating signal of target frequency, and resonant circuit includes capacitive array and modulation field coil, and the first end and the driver of capacitive array are connected, and the second end and the modulation field coil of capacitive array are connected, and modulation field coil is used for providing the modulation magnetic field for the EPR probe.
In some embodiments, as shown in fig. 7, a method of controlling a variable frequency modulation field system may include:
s301, obtaining the current in the resonant circuit.
And S302, adjusting the capacitance value of the capacitor array according to the current so as to enable the resonant circuit to be in a resonant state.
It should be noted that, for other specific implementations of the control method of the frequency-variable modulation field system according to the embodiment of the present invention, reference may be made to the specific implementations of the frequency-variable modulation field system according to the above-mentioned embodiment of the present invention.
It should be noted that the logic and/or steps represented in the flowcharts or otherwise described herein, such as an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following technologies, which are well known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be interconnected within two elements or in a relationship where two elements interact with each other unless otherwise specifically limited. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. A variable frequency modulation field system, the system comprising:
a driver for providing an alternating current signal of a target frequency;
a resonant circuit comprising a capacitive array and a modulation field coil, a first end of the capacitive array being connected to the driver and a second end of the capacitive array being connected to the modulation field coil, the modulation field coil being for providing a modulated magnetic field to the EPR probe;
the current monitoring device is connected with the resonant circuit and used for monitoring the current in the resonant circuit;
and the controller is respectively connected with the capacitor array and the current monitoring device and is used for adjusting the capacitance value of the capacitor array according to the current so as to enable the resonant circuit to be in a resonant state.
2. The frequency variable modulation field system of claim 1, wherein the controller is configured to adjust a capacitance value of the capacitor array based on the current to bring the resonant circuit into resonance when the target frequency changes or an inductance of the EPR probe changes.
3. The frequency variable modulation field system of claim 1, wherein the capacitor array comprises n-1 switched capacitor branches and a short circuit branch, the n-1 switched capacitor branches being connected in parallel and in parallel with the short circuit branch forming a first parallel point and a second parallel point, the first parallel point being connected to the driver and the second parallel point being connected to the modulation field coil, wherein each switched capacitor branch comprises a capacitor and a controllable switch connected in series, and the short circuit branch comprises a controllable switch.
4. The frequency variable modulation field system of claim 1, further comprising:
and the amplifier is connected between the driver and the resonant circuit and is used for amplifying the alternating current signal.
5. The frequency variable modulation field system of claim 3, wherein the controller is specifically configured to:
determining an initial sequence of capacitance values, wherein the initial sequence of capacitance values is adjustable by the capacitor array by a minimum capacitance value of 0 and a maximum capacitance value of C e And initial first, second and third capacitance values, 0 < first capacitance value < second capacitance value < third capacitance value < C e ；
Sequentially adjusting the capacitance value of the capacitor array to a current first capacitance value, a current second capacitance value and a current third capacitance value, and acquiring a corresponding first current peak-to-peak value, a corresponding second current peak-to-peak value and a corresponding third current peak-to-peak value;
determining the maximum value of the first current peak-to-peak value, the second current peak-to-peak value and the third current peak-to-peak value, and determining the adjustable capacitance value range of the capacitor array according to the maximum value and the current capacitance value sequence;
judging whether the adjustable capacitance value range meets a preset segmentation condition or not;
and if so, taking the capacitance value corresponding to the maximum value as a final capacitance value, otherwise, updating the current capacitance value sequence, the first capacitance value, the second capacitance value and the third capacitance value according to the adjustable capacitance value range, and returning to the step of sequentially adjusting the capacitance values of the capacitor array to the current first capacitance value, the current second capacitance value and the current third capacitance value.
6. The frequency-variable modulation field system according to claim 5, wherein the initial first, second, and third capacitance values are a pair set [0, C [ ] e ]And performing quartering to obtain three equal capacitance values.
7. The frequency variable modulation field system according to claim 5, wherein said determining an adjustable capacitance range for said capacitor array based on said maximum value and a current sequence of capacitance values comprises:
obtaining a first intermediate capacitance value according to the capacitance value corresponding to the maximum value and the last capacitance value of the capacitance value, obtaining a second intermediate capacitance value according to the capacitance value corresponding to the maximum value and the next capacitance value of the capacitance value, and determining that the adjustable capacitance value range of the capacitor array is the range formed by the first intermediate capacitance value and the second intermediate capacitance value;
wherein updating the current capacitance sequence, the first capacitance, the second capacitance, and the third capacitance according to the adjustable capacitance range comprises:
and adding the first intermediate capacitance value and the second intermediate capacitance value into a current capacitance value sequence, and updating the current first capacitance value, second capacitance value and third capacitance value into the first intermediate capacitance value, the capacitance value corresponding to the maximum value and the second intermediate capacitance value.
8. The frequency variable modulation field system of claim 3, wherein the controller is specifically configured to:
calculating a target capacitance value according to the target frequency and the inductance value of the EPR probe;
finding a capacitance value C closest to the target capacitance value from a capacitance value sequence consisting of adjustable capacitance values of the capacitor array s And C s Last capacitance value C of s-1 And the next capacitance value C s+1 ；
Sequentially adjusting the capacitance value of the capacitor array to C s 、C s-1 And C s+1 And obtaining the corresponding current peak value I s 、I s-1 And I s+1 ；
Judgment of I s 、I s-1 And I s+1 Maximum value of (2);
if I s At the maximum, then C is added s As the final capacitance value;
if I s-1 At maximum, finding C from the capacitance value sequence s-1 Last capacitance value C of s-2 And adjusting the capacitance value of the capacitor array to C s-2 Obtaining the corresponding current peak value I s-2 And in I s-2 Is less than I s-1 When it is, C is s-1 As a result of the final capacitance value,otherwise, continue to find C s-3 Up to I s-x Is less than I s-x+1 Is shown by s-x+1 Corresponding to C s-x+1 As the final capacitance value;
if I s+1 At maximum, finding C from the capacitance value sequence s+1 Next capacitance value C of s+2 And adjusting the capacitance value of the capacitor array to C s+2 Obtaining the corresponding current peak value I s+2 And in I s+2 Is less than I s+1 When it is, C s+1 As the final capacitance value, otherwise, continuously finding out C s+3 Up to I s+x+1 Is less than I s+x A first reaction of s+x Corresponding to C s+x As the final capacitance value.
9. An EPR spectrometer, comprising: EPR probe, a frequency variable modulation field system as claimed in any one of claims 1 to 8.
10. A method of controlling a frequency variable modulation field system comprising a driver for providing an alternating signal at a target frequency and a resonant circuit comprising a capacitive array and a modulation field coil, a first end of the capacitive array being connected to the driver and a second end of the capacitive array being connected to the modulation field coil, the modulation field coil being for providing a modulated magnetic field for an EPR probe, the method comprising:
acquiring current in the resonant circuit;
and adjusting the capacitance value of the capacitor array according to the current so as to enable the resonant circuit to be in a resonant state.
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1306622A (en) * | 1998-04-22 | 2001-08-01 | 西南研究会 | Porosity and permeability measurement of underground formations contg. crude oil, using epr response data |
| CN102710300A (en) * | 2012-05-11 | 2012-10-03 | 北京握奇数据系统有限公司 | Radio frequency identification (RFID) loop antenna matching method, antenna, electronic tag and reader |
| CN103487074A (en) * | 2013-10-12 | 2014-01-01 | 重庆邮电大学 | Method for processing FBG (fiber bragg grating) sensing signal by utilizing three-point peek-seeking algorithm |
| CN103595262A (en) * | 2013-11-04 | 2014-02-19 | 江苏科意达机械有限公司 | Frequency adjusting circuit for wireless charging system |
| CN104111691A (en) * | 2014-07-08 | 2014-10-22 | 安徽金峰新能源股份有限公司 | Photovoltaic inverter MPPT control method based on three-point comparison method |
| CN104577328A (en) * | 2015-01-22 | 2015-04-29 | 山东大学 | RFID antenna and automatic matching method thereof |
| CN107389995A (en) * | 2017-08-15 | 2017-11-24 | 华电电力科学研究院 | Adjust series resonant inverter Q circuit and its method of testing |
| CN108282028A (en) * | 2017-12-29 | 2018-07-13 | 上海广为美线电源电器有限公司 | The tuning methods and system of resonance type wireless electric energy transmission based on current amplitude |
| CN114660519A (en) * | 2020-12-22 | 2022-06-24 | 布鲁克碧奥斯平有限公司 | EPR spectrometer with at least one pole piece made at least partially of a functional material |
-
2022
- 2022-07-25 CN CN202210876821.6A patent/CN115079069A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1306622A (en) * | 1998-04-22 | 2001-08-01 | 西南研究会 | Porosity and permeability measurement of underground formations contg. crude oil, using epr response data |
| CN102710300A (en) * | 2012-05-11 | 2012-10-03 | 北京握奇数据系统有限公司 | Radio frequency identification (RFID) loop antenna matching method, antenna, electronic tag and reader |
| CN103487074A (en) * | 2013-10-12 | 2014-01-01 | 重庆邮电大学 | Method for processing FBG (fiber bragg grating) sensing signal by utilizing three-point peek-seeking algorithm |
| CN103595262A (en) * | 2013-11-04 | 2014-02-19 | 江苏科意达机械有限公司 | Frequency adjusting circuit for wireless charging system |
| CN104111691A (en) * | 2014-07-08 | 2014-10-22 | 安徽金峰新能源股份有限公司 | Photovoltaic inverter MPPT control method based on three-point comparison method |
| CN104577328A (en) * | 2015-01-22 | 2015-04-29 | 山东大学 | RFID antenna and automatic matching method thereof |
| CN107389995A (en) * | 2017-08-15 | 2017-11-24 | 华电电力科学研究院 | Adjust series resonant inverter Q circuit and its method of testing |
| CN108282028A (en) * | 2017-12-29 | 2018-07-13 | 上海广为美线电源电器有限公司 | The tuning methods and system of resonance type wireless electric energy transmission based on current amplitude |
| CN114660519A (en) * | 2020-12-22 | 2022-06-24 | 布鲁克碧奥斯平有限公司 | EPR spectrometer with at least one pole piece made at least partially of a functional material |
Non-Patent Citations (5)
| Title |
|---|
| 付雷 等: "石英音叉陀螺多频率激励自启动算法", 《中国惯性技术学报》 * |
| 李心广: "《电路与电子技术基础》", 31 December 2021 * |
| 范凯 等: "EPR在体测量专用调制磁场驱动装置", 《波谱学杂志》 * |
| 马礼敦: "《高等结构分析》", 31 May 2006 * |
| 龙腾飞 等: "MPPT 的三点比较法与登山法比较分析", 《大众科技》 * |
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