Current comparator based on diamond NV color center

Abstract

According to the current comparator based on the diamond NV color center, an iron core module comprises an annular iron core, and the iron core module is arranged on a primary current path in a sleeving mode; the primary feedback module comprises a direct current sensor, a secondary winding and a driven current source; the secondary winding is wound on the annular iron core of the iron core module, the driven current source generates output current, the output current flows through the secondary winding to generate reverse magnetic potential in the annular iron core, and primary magnetic balance in the iron core is achieved; and the secondary feedback module comprises a diamond NV color center magnetic detector module and a PID controller, the diamond NV color center magnetic detector module measures the unbalanced magnetic potential, and the PID controller compensates the current in the secondary winding according to the unbalanced magnetic potential, so that zero magnetic flux is always locked in the iron core. According to the technical scheme, the diamond NV color center magnetic detector module is introduced into the secondary feedback module, the unbalanced magnetic potential in the iron core can be detected in a high-precision mode by means of quantum characteristics, and the measurement precision is greatly improved through the sensitive sensing capacity of the secondary feedback module on tiny magnetic field changes.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical measurement devices, and particularly to a current comparator based on diamond NV centers. Background Art

[0002] A direct current (DC) current comparator is a device based on the principle of magnetic modulation, used for accurately measuring and comparing DC currents, and is widely applied in the fields of metrological calibration and scientific research. When measuring a DC current, it can accurately compare the magnitudes of two or more DC currents and determine the proportional relationship between them.

[0003] The traditional DC current comparator based on the ampere-turn balance and magnetic modulation principles features rapidity. During operation, when the primary-side current changes, through the ampere-turn balance principle, the comparator can quickly cause a corresponding change in the magnetic flux in the iron core. The magnetic modulation link will immediately respond to this change in magnetic flux. The modulation winding and detection winding inside it will quickly generate a modulation signal and a detection signal according to the change in magnetic flux. Due to this reaction mechanism based on electromagnetic induction being very sensitive, and the structural design of the entire system enabling an efficient signal transmission and processing path, the comparator can respond to the change in DC current within an extremely short time, thereby achieving rapid comparison and measurement of DC currents, quickly determining the difference between the measured current and the standard current, and further ensuring that accurate current comparison information can be provided in a timely manner in application scenarios where rapid detection of DC current changes is required.

[0004] Traditional DC current comparators mainly rely on the ampere-turn balance principle to achieve measurement, and usually adopt a double-core differential magnetic modulator structure. However, after years of efforts, the accuracy of the magnetic modulator type current comparator has only reached a certain level. Due to the difficulty in achieving ideal actual coupling, limitations of high-permeability materials, and the influence of hysteresis characteristics and the Pockels effect, the accuracy of the magnetic modulator type current comparator is restricted by the difficulty in achieving ampere-turn balance due to leakage magnetic flux and the imperfect technical means for monitoring ampere-turn balance. Among existing DC current measurement devices, although cryogenic comparators can achieve higher measurement sensitivity, they have not been widely applied due to their relatively harsh application scenarios. How to improve the measurement sensitivity of the DC current comparator system has become an urgent problem in this field. Summary of the Invention

[0005] In order to improve the measurement sensitivity of the DC current comparator, the present invention provides a current comparator based on diamond NV centers.

[0006] The technical solution of the present invention provides a current comparator based on diamond NV centers, including an iron core module, a first-level feedback module, and a second-level feedback module; The iron core module includes an annular iron core, and the iron core module is sleeved on the primary current path of a primary active current source; The primary feedback module is a feed - forward loop, which includes a DC sensor, a secondary winding, and a slave current source; the DC sensor is connected in series in the current path of the primary active current source to be measured, the secondary winding is wound around the toroidal iron core of the iron core module, and the slave current source generates an output current in the feed - forward loop according to the information obtained by the DC sensor. This output current flows through the secondary winding to generate a reverse magnetomotive force in the toroidal iron core, which is used to offset the magnetic flux of the magnetomotive force in the primary current path in the toroidal iron core, achieving a preliminary magnetic balance in the iron core. The secondary feedback module includes a diamond NV - center magnetic detector module and a PID controller. The diamond NV - center magnetic detector module is used to measure the unbalanced magnetomotive force caused by the current in the iron core, and the PID controller is used to compensate the current in the secondary winding according to the unbalanced magnetomotive force detected by the diamond NV - center magnetic detector module, so that zero magnetic flux is always locked inside the iron core.

[0007] Preferably, the secondary feedback module further includes a DAC module and a signal conditioning circuit; The DAC module is used to convert the PID control signal into an analog signal, which is sequentially connected to the signal conditioning circuit. The signal conditioning circuit is used to pre - process the signal, perform stability correction and power drive, so that the current of the slave current source flows through the secondary winding to offset the remaining unbalanced magnetomotive force.

[0008] Preferably, the DC amplifier circuit of the signal conditioning circuit realizes power correction, and the power amplifier circuit of the signal conditioning circuit drives the secondary current balance.

[0009] Preferably, the signal conditioning circuit includes a pre - amplifier, filter elements, and a voltage - follower module; The pre - amplifier preliminarily amplifies the weak electrical signal output by the fluorescence detection module to increase the amplitude of the signal for subsequent circuit processing; the filter elements are used to remove the noise and interference components in the signal and extract or retain signals in a specific frequency range according to needs; the voltage - follower module is used for buffering and isolation to avoid generating a load effect on the weak signal of the previous stage and prevent interference between the front and rear stages.

[0010] Preferably, the signal conditioning circuit includes a pre - amplifier, filter elements, and a voltage - follower module; The pre - amplifier preliminarily amplifies the weak electrical signal output by the fluorescence detection module to increase the amplitude of the signal for subsequent circuit processing; the filter elements are used to remove the noise and interference components in the signal and extract or retain signals in a specific frequency range according to needs; the voltage - follower module is used for buffering and isolation to avoid generating a load effect on the weak signal of the previous stage and prevent interference between the front and rear stages.

[0011] Preferably, the two diamond NV color center magnetic detector module has a diamond NV color center sample for detecting the unbalanced magnetic potential in the iron core; the annular iron core has an air gap for avoiding magnetic saturation, and the diamond NV color center sample is placed in the air gap of the annular iron core.

[0012] Preferably, the two miniature fiber optic probes include a filter, a dichroic mirror, an objective lens, a diamond NV color center sample, a laser source module, a photoelectric detection module, and a fluorescence collection lens; The filter screens light of specific wavelengths, the dichroic mirror processes light in different directions, the objective lens is used to focus the light, the fluorescence collection lens is responsible for collecting the fluorescence signal generated by the sample, the laser source module provides the necessary laser source, and the photoelectric detection module is responsible for receiving and converting the light signal.

[0013] The primary feedback module in the technical solution of the present invention reduces the demand for the measurement bandwidth of the secondary feedback module. The secondary feedback module introduces a diamond NV color center magnetic detector module, which can detect the unbalanced magnetic potential in the iron core with high precision by using quantum characteristics. Its keen perception of tiny magnetic field changes greatly improves the measurement accuracy. The subsequent optimization processing of the signal by the electronic circuit also ensures the validity of the data, and solves the problem that the traditional magnetic modulation current comparator is limited by the capacitive error of ferromagnetic materials and is difficult to further improve the measurement accuracy. At the same time, the collaborative work of each part can effectively resist external interference, maintain high precision and stability under different current conditions, and is suitable for a variety of application scenarios with demanding requirements on precision and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a flow chart of a current comparator based on two-stage feedback of diamond NV color center of the present invention; Figure 2 It is a principle block diagram of the present invention based on secondary feedback of diamond NV color center.

[0015] In the figure: 1: primary active current source; 2: iron core module; 3: DC sensor; 4: feedforward loop; 5: driven current source; 6: diamond NV color center magnetic sensor; 7: PID controller; 8: power amplifier module; 9: secondary winding; 10: zero flux; 11: DAC module; 12: signal conditioning circuit; 13: DC amplifier module; 14: primary feedback module. DETAILED DESCRIPTION

[0016] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. In this specification, the size ratios in the drawings do not represent the actual size ratios, but are only used to reflect the relative position relationship and connection relationship between the components. Components with the same name or the same number represent similar or identical structures and are only for illustrative purposes.

[0017] The diamond NV color center DC current comparator of the present application includes a core module, a primary feedback module, and a secondary feedback module.

[0018] The core module among them includes a circular core. The circular core has an air gap for avoiding magnetic saturation. In the embodiment, the width of the air gap is about 2 mm. In order to avoid magnetic leakage interference and the interference of external magnetic sources, a magnetic shielding cylinder is sleeved outside the circular core. The magnetic shielding cylinder achieves this effect by using a material with high magnetic permeability. The core module is sleeved on the primary current path of the primary active current source. Specifically, that is, the primary active current source to be measured passes through the circular region of the circular core. The circular core is mainly spliced by silicon steel sheets stacked together. In order to reduce eddy current loss, the silicon steel sheets are insulated from each other, such as by coating an insulating paint on the surface of the silicon steel sheets or using other insulating materials for isolation.

[0019] The primary feedback module is a feed-forward loop. The feed-forward loop includes a DC sensor, a secondary winding, and a slave current source. The DC sensor is connected in series in the current path of the primary active current source to be measured. The DC sensor is used to sense the magnitude, direction, and change of the current and convert it into an electrical signal, such as a Hall DC sensor. The secondary winding is wound around the circular core of the core module. The slave current source is used to generate a corresponding output current in the feed-forward loop according to the information obtained by the DC sensor. The output current flows through the secondary winding to generate a reverse magnetic potential in the circular core. The purpose is to achieve the basic cancellation of the magnetic flux of the reverse magnetic potential and the magnetic potential of the primary current path in the circular core, that is, to achieve the preliminary current balance of the transformer system composed of the circular core, the primary current path, and the primary winding.

[0020] The primary feedback module also includes a controller. The feed-forward control is mainly realized by the controller. The controller is the core processing unit. It receives the output signal of the DC sensor and generates a control signal to control the output current of the slave current source. In the feed-forward loop with the controller as the core, there are also a compensator and a transmitter. The compensator among them can compensate the characteristics of the controlled object to improve the accuracy; the transmitter converts and amplifies the weak signal of the current sensor to meet the input requirements of the controller. The controller can be a controller based on PID tuning. The control signal is generated through the proportional, integral, and differential operations of the controller to control the output of the slave current source. The transmitter converts and amplifies the weak signal of the current sensor to meet the input requirements of the controller. Specifically, the primary feedback circuit connects a current sensor (Hall current sensor) in series in the primary active current source to be measured. This sensor can sensitively sense the magnitude, direction, and change of the current of the active current source, convert the information into an electrical signal, and transmit it to the slave current source through the feed-forward loop. The slave current source generates a current according to the internal algorithm to cancel most of the unbalanced magnetic potential. If the current of the active current source fluctuates, the sensor quickly captures and transmits the signal. The slave current source calculates the compensation current accordingly to initially balance the current and reduce the subsequent measurement error.

[0021] The secondary feedback module includes a diamond NV color center magnetic detector module and a PID controller. The diamond NV color center magnetic detector module is used to measure the unbalanced magnetic potential caused by the current in the iron core. The PID controller is used to compensate the current in the secondary winding according to the unbalanced magnetic potential detected by the diamond NV color center magnetic detector module, so that the unbalanced magnetic flux in the secondary winding is always locked to zero flux. The secondary feedback circuit is the core of high-precision measurement. The diamond NV color center magnetic detector and subsequent electronic circuits are responsible for accurately measuring the unbalanced magnetic potential of the iron core, and the detector senses tiny magnetic field changes by quantum effects. The subsequent electronic circuit amplifies, filters, and digitally processes weak signals. The PID controller receives its signal and generates a control signal through PID calculation to lock the unbalanced magnetic flux to zero flux. The diamond NV color center secondary feedback control uses the magnetic field signal measured by the NV color center to track the zero flux point through the PID controller.

[0022] The secondary feedback module also includes a DAC module and a signal conditioning circuit. The DAC module is used to convert the PID control signal into an analog signal, which is sequentially connected to the signal conditioning circuit, the DC amplifier module, and the power amplifier, and is used to pre-process the signal, perform stability correction, and power drive, respectively, so that the current of the slave current source offsets the residual unbalanced magnetic potential through the secondary winding. The active filter circuit of the signal conditioning circuit processes the signal, the DC amplifier circuit of the signal conditioning circuit realizes power correction to improve the stability of the system, and the power amplifier circuit of the signal conditioning circuit drives the secondary current balance. The DAC module converts the digital control signal into an analog signal, which is sequentially input into the signal conditioning circuit for amplitude modulation, phase modulation, and impedance matching, and then the DC amplifier module enhances the driving capability. Finally, the power amplifier module drives the slave current source to generate current to offset the residual unbalanced magnetic potential, achieve high-precision comparative measurement, and ensure the accuracy and stability of the device under different currents.

[0023] The DAC module converts the digital control signal into an analog signal, which is then sent to the signal conditioning circuit for amplitude modulation, phase modulation, and impedance matching. The DC amplifier module then enhances the driving capability, and finally the power amplifier module drives the slave current source to generate current. , offset the residual unbalanced magnetic potential, achieve high-precision comparative measurement, and ensure the accuracy and stability of the device under different currents.

[0024] The primary feedback is achieved by connecting a current sensor in series with the primary coil, and controlling the slave current source through a feedforward loop to generate a current that offsets most of the unbalanced magnetic potential. The secondary feedback uses the diamond NV color center magnetic sensor to measure the unbalanced magnetic potential, and the PID controller and power amplifier feedback output the current to offset the remaining unbalanced magnetic potential. Under magnetic balance, the current to be measured in the primary coil is measured through the relationship between the number of winding turns.

[0025]

[0026] The currents of both the primary feedback module and the secondary feedback module flow into the secondary winding to cancel the unbalanced magnetic potential. When the unbalanced magnetic potential of the iron core is 0, the measured active current source to be measured on the primary side : ; wherein, is the number of turns of the primary winding, is the number of turns of the secondary winding, is the output current of the primary feedback module, is the output current of the secondary feedback module.

[0027] The signal conditioning circuit includes a preamplifier, filter components, and a voltage follower module. The preamplifier preliminarily amplifies the weak electrical signal output by the fluorescence detection module to increase the amplitude of the signal for subsequent circuit processing. The filter components are mainly used to remove the noise and interference components in the signal, and at the same time, specific frequency range signals can be extracted or retained according to needs. The voltage follower module plays a role in buffering and isolation, avoiding the load effect on the weak signal of the previous stage, preventing mutual interference between the front and rear stages, and ensuring system stability; achieving impedance matching, reducing signal transmission reflection and loss, ensuring signal integrity and accuracy; improving the driving ability, driving subsequent low-impedance circuits and devices with sufficient current, avoiding signal distortion or attenuation; and also maintaining signal stability, reducing distortion and noise, providing a reliable basis for subsequent signal processing and analysis, and improving the measurement accuracy and stability of the system.

[0028] The DC amplifier uses an integrated operational amplifier. A low-noise and high-precision integrated operational amplifier is used to amplify the weak DC signal output by the diamond magnetic detector, which can effectively improve the measurement accuracy. Each component of the micro fiber optic probe closely cooperates to collect and transmit the unbalanced magnetic potential information. The filter first selects light of a specific wavelength to prevent stray light from interfering with the sample. The filtered light is irradiated onto the objective lens through a dichroic mirror, and the objective lens focuses the light on the sample to cause a change in its quantum state to generate a fluorescence signal. Part of the fluorescence signal is introduced into the fluorescence collection lens by the dichroic mirror and converges and outputs, providing a data basis for the device to detect the unbalanced magnetic potential.

[0029] The diamond NV color center magnetic detector module is integrated into the micro-fiber probe. The various components of the micro-fiber probe work closely together to collect and transmit unbalanced magnetic potential information. The filter first screens light of a specific wavelength to prevent stray light from interfering with the sample. After filtering, the light is illuminated by the dichroic mirror to the objective lens, which focuses the light on the sample to cause its quantum state to change and produce a fluorescence signal. Part of the fluorescence signal is introduced by the dichroic mirror into the fluorescence collection lens for convergence and output, providing the device with the basis for unbalanced magnetic potential detection data. The micro-fiber probe is mainly composed of components such as filters, dichroic mirrors, objective lenses, diamond NV color center samples, and fluorescence collection lenses. These components each play a unique role. The filter can screen light of a specific wavelength, the dichroic mirror can process light in different directions, the objective lens is used to focus light, the diamond NV color center sample is the key material basis for detection, and the fluorescence collection lens is responsible for collecting the fluorescence signal generated by the sample. They work together to realize the effective collection and transmission of information related to unbalanced magnetic potential by the micro-fiber probe. The miniature fiber-optic diamond NV color center probe in the diamond NV color center magnetic detector module is the front-end component of the detection. The laser source module provides the necessary laser source for detection. The photoelectric detection module is responsible for receiving and converting optical signals. The frequency-agile microwave source works within a specific frequency range. The phase-locked demodulation module and the frequency calculation module work together to complete the detection task of the residual unbalanced magnetic potential. In the diamond NV color center magnetic detector module, the filter of the miniature fiber-optic probe can filter out stray light according to the preset wavelength range to improve the signal-to-noise ratio. The dichroic mirror distributes light according to the characteristics of light, allowing the 532nm laser to accurately illuminate the diamond NV color center sample and guide the fluorescence to the fluorescence collection lens. The objective lens focuses the collimated light, allowing the laser to act efficiently on the sample and also allowing the fluorescence signal to be efficiently transmitted. The diamond NV color center sample generates a detectable signal under the action of the magnetic field. The fluorescence collection lens collects the sample fluorescence signal, which contains key information about the unbalanced magnetic potential of the iron core. The laser source module provides laser excitation for the sample, the photoelectric detection module converts the fluorescence signal into an electrical signal, the frequency-agile microwave source regulates the quantum state of the sample, and the phase-locked demodulation module works together with the frequency calculation module. The former extracts specific frequency components, and the latter calculates the magnitude and direction of the residual unbalanced magnetic potential, providing key data for high-precision measurement.

[0030] In this solution, the primary feedback module reduces the demand for the measurement bandwidth of the secondary feedback module. The secondary feedback module introduces a diamond NV color center magnetic detector module, which uses quantum characteristics to detect the unbalanced magnetic potential in the iron core with high precision. Its keen perception of tiny magnetic field changes greatly improves the measurement accuracy. The subsequent optimization of the signal by the electronic circuit also ensures the validity of the data, solving the problem that the traditional magnetic modulation current comparator is limited by the capacitive error of ferromagnetic materials and is difficult to further improve the measurement accuracy. At the same time, the coordinated work of each part can effectively resist external interference, maintain high precision and stability under different current conditions, and is suitable for a variety of application scenarios with demanding requirements for precision and stability.

[0031] The above content is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A current comparator based on diamond NV color centers, characterized in that, It includes an iron core module, a primary feedback module, and a secondary feedback module; The iron core module includes an annular iron core, and the iron core module is sleeved on the primary current path of the primary active current source; The primary feedback module is a feedforward loop, which includes a DC sensor, a secondary winding, and a driven current source; the DC sensor is connected in series in the current path of the primary active current source to be measured, the secondary winding is wound around the annular iron core of the iron core module, and the driven current source generates an output current in the feedforward loop according to the information obtained by the DC sensor. This output current flows through the secondary winding to generate a reverse magnetomotive force in the annular iron core, which is used to cancel the magnetic flux of the magnetomotive force in the primary current path in the annular iron core, realizing preliminary magnetic balance in the iron core; The secondary feedback module includes a diamond NV center magnetic detector module and a PID controller. The diamond NV center magnetic detector module is used to measure the unbalanced magnetomotive force caused by the current in the iron core, and the PID controller is used to compensate the current in the secondary winding according to the unbalanced magnetomotive force detected by the diamond NV center magnetic detector module, so that zero magnetic flux is always locked inside the iron core.

2. The current comparator based on diamond NV centers according to claim 1, characterized in that The secondary feedback module also includes a DAC module and a signal conditioning circuit; The DAC module is used to convert the PID control signal into an analog signal and is sequentially connected to the signal conditioning circuit. The signal conditioning circuit is used to preprocess the signal, perform stability correction and power drive, so that the current of the driven current source flows through the secondary winding to cancel the remaining unbalanced magnetomotive force.

3. The current comparator based on diamond NV color centers according to claim 2, characterized in that, The DC amplification circuit of the signal conditioning circuit realizes power correction, and the power amplification circuit of the signal conditioning circuit drives the secondary current balance.

4. The current comparator based on diamond NV color centers according to claim 2, characterized in that, The signal conditioning circuit includes a preamplifier, filter elements, and a voltage follower module; The preamplifier preliminarily amplifies the weak electrical signal output by the fluorescence detection module to increase the amplitude of the signal for subsequent circuit processing; The filter elements are used to remove the noise and interference components in the signal and extract or retain signals in a specific frequency range as needed; the voltage follower module is used for buffering isolation to avoid generating a load effect on the weak signal of the previous stage and prevent interference between the front and rear stages.

5. The current comparator based on diamond NV color centers according to claim 1, characterized in that, The signal conditioning circuit includes a preamplifier, filter elements, and a voltage follower module; The preamplifier preliminarily amplifies the weak electrical signal output by the fluorescence detection module to increase the amplitude of the signal for subsequent circuit processing; The filter elements are used to remove the noise and interference components in the signal and extract or retain signals in a specific frequency range as needed; the voltage follower module is used for buffering isolation to avoid generating a load effect on the weak signal of the previous stage and prevent interference between the front and rear stages.

6. The current comparator based on diamond NV color centers according to claim 1, characterized in that, The diamond NV center magnetic detector module has a diamond NV center sample for detecting the unbalanced magnetomotive force in the iron core; the annular iron core has an air gap for avoiding magnetic saturation, and the diamond NV center sample is placed in the air gap of the annular iron core.

7. The current comparator based on diamond NV color centers according to claim 6, characterized in that, The micro-optical fiberized probe includes a filter, a dichroic mirror, an objective lens, a diamond NV center sample, a laser source module, a photoelectric detection module, and a fluorescence collection lens; The filter screens light of a specific wavelength, the dichroic mirror processes light in different directions, the objective lens is used to focus the light, the fluorescence collection lens is responsible for collecting the fluorescence signal generated by the sample, the laser source module provides the necessary laser source, and the photoelectric detection module is responsible for receiving and converting the optical signal.

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