Measurement and calibration system and method of quantum current sensor

Abstract

The invention discloses a measurement and calibration system and method for a quantum current sensor, and belongs to the technical field of quantum measurement, and the system comprises a standard calibration system which comprises a DC / AC standard current source, a standard current sensor and a quantum current sensor; the microwave system is used for applying a microwave signal with a set frequency to the quantum current sensor so as to excite or regulate and control a quantum state energy level structure in the quantum current sensor; the optical system is used for exciting a quantum state in the quantum current sensor and acquiring a related optical response signal; and the signal processing system is used for respectively acquiring output signals of the standard current sensor and the quantum current sensor, analyzing and processing the output signals and generating calibration data for performing error compensation or performance correction on the quantum current sensor. According to the invention, real-time calibration of the quantum current sensor in a range of 10 [mu] A to 70 kA can be realized, and the linearity, sensitivity and temperature stability of the quantum current sensor are effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of quantum measurement technology, and in particular to a measurement and calibration system and method for a quantum current sensor. Background Art

[0002] Quantum current sensors are a new type of sensor that utilizes quantum mechanical principles (such as electron spin state transitions and quantum interference effects) to achieve highly sensitive and high-precision current measurement. These sensors are widely used in high-precision metering, extreme condition monitoring, and power system security assessments, offering unique advantages such as non-contact measurement, quantum traceability, and a wide range of response.

[0003] Currently, quantum current sensors based on diamond nitrogen-vacancy color centers (NV centers) have become an important direction in quantum measurement research because they operate at room temperature and pressure and are sensitive to weak magnetic fields. However, due to the extremely high sensitivity of quantum states, their measurement stability is affected by various environmental disturbances in practical applications, and they still face a series of technical problems that need to be solved:

[0004] Severe zero-point drift: The energy level structure of the NV center is easily affected by external factors such as ambient temperature and stress fields. For example, a temperature fluctuation of ±0.1K can cause a zero-point drift of ±5%, affecting the quantum current output benchmark.

[0005] Lattice stress coupling: The spin resonance frequency is highly sensitive to the stress field, with a typical drift coefficient of up to 1 MHz / MPa. Frequent mechanical vibrations in industrial environments can easily induce measurement errors.

[0006] The efficiency of quantum state initialization decreases: the initialization state of the NV color center will experience "monthly drift" over time and operating conditions, with a drift rate exceeding 2%, causing the quantum current response to decay over time;

[0007] Lack of a dedicated calibration system: Existing electrical calibration methods are usually based on macroscopic physical models, which are incompatible with characteristics such as energy level transitions, microwave excitation, and optical readout in quantum systems, and cannot achieve targeted error compensation and performance correction. Summary of the Invention

[0008] In view of the above-mentioned problems, the present invention is proposed.

[0009] Therefore, the technical problem solved by the present invention is to solve the problem of real-time calibration of quantum current sensors under complex working conditions. It achieves high-precision and high-reliability current calibration to meet the calibration requirements of quantum current sensors in different scenarios, including leakage current and working current.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions: a measurement and calibration system for a quantum current sensor, comprising:

[0011] a standard calibration system, comprising a DC / AC standard current source, a standard current sensor, and a quantum current sensor;

[0012] a microwave system, for applying a microwave signal of a set frequency to the quantum current sensor to excite or regulate the quantum state energy level structure inside it;

[0013] an optical system, for exciting the quantum state in the quantum current sensor and obtaining a related optical response signal;

[0014] a signal processing system, for respectively collecting the output signals of the standard current sensor and the quantum current sensor, and performing analysis and processing to generate calibration data for error compensation or performance correction of the quantum current sensor.

[0015] As a preferred scheme of the quantum current sensor measurement and calibration system, wherein: the standard current source is used to output a standard current signal in a predetermined current range, the standard current sensor is used to measure the standard current signal, and the quantum current sensor is used to receive the standard current signal and output a corresponding quantum measurement signal to realize comparison and calibration between the standard current signal and the quantum measurement signal.

[0016] The standard current sensor comprises a plurality of current sensing modules for signal detection corresponding to different current ranges respectively, and the plurality of current sensing modules are configured in a segmented manner to form a standard current measurement unit.

[0017] As a preferred scheme of the quantum current sensor measurement and calibration system, wherein: the quantum current sensor comprises a sensitive unit with a diamond NV color center structure, and the sensitive unit forms an optical response for outputting a quantum measurement signal through electron spin state transition under the joint action of the microwave system and the optical system.

[0018] As a preferred scheme of the quantum current sensor measurement and calibration system, wherein: the microwave system comprises a microwave signal source for generating a microwave signal of a set frequency based on a phase-locked loop and a direct digital frequency synthesis technology.

[0019] A microwave power amplifier connected to the microwave signal source is used to amplify the microwave signal to a power level sufficient to drive the atomic transition inside the quantum current sensor.

[0020] A microwave transmission path is used to transmit the amplified microwave signal to the quantum current sensor to induce the energy level splitting or transition of the spin state inside it, for realizing quantum state regulation related to current intensity.

[0021] As a preferred scheme of the measurement and calibration system of a quantum current sensor, wherein: the optical system comprises a laser configured to output linearly polarized laser light;

[0022] A beam splitter, the input end of which is connected with the laser, is used to divide the linearly polarized laser light into reference light and sensing light;

[0023] A circulator, one end of which is connected with the beam splitter, is used to guide the sensing light into the quantum current sensor and return;

[0024] A filter connected to the output end of the circulator is used to filter out the excitation light component in the return light;

[0025] A photodetector connected to the output end of the filter is used to convert the filtered light signal into an electrical signal.

[0026] As a preferred scheme of the measurement and calibration system of a quantum current sensor, wherein: the signal processing system comprises a signal conditioning module for transimpedance amplification, filtering and gain control of the analog signals output by the standard current sensor and the photodetector to adapt to subsequent data acquisition;

[0027] A data acquisition module connected to the signal conditioning module is used to convert the conditioned analog signals into digital signals synchronously;

[0028] An analysis and processing module connected to the data acquisition module is used to perform sliding average, spectral analysis and linear fitting algorithm operations on the digital signals to extract the performance indicators of the quantum current sensor;

[0029] A communication module is used to transmit the calibration data or measurement results processed by the analysis and processing module to the host computer for storage and display.

[0030] As a preferred scheme of the measurement and calibration system of a quantum current sensor, wherein: the signal processing system further comprises a host computer system, which is used to receive the calibration data transmitted by the communication module and perform the following operations:

[0031] Waveform display, spectral analysis and parameter extraction are performed on the received data;

[0032] According to the error relationship between the standard current signal and the quantum measurement signal, the calibration parameters for linear compensation, sensitivity correction and temperature drift correction are calculated and output;

[0033] The calibration parameters are fed back to the quantum current sensor for dynamic optimization of its measurement performance.

[0034] As a preferred scheme of the measurement and calibration system of the quantum current sensor, wherein: the host computer system executes parameter correction strategies according to different calibration scenarios, including, in a zero-point calibration mode, obtaining a residual current value of the standard current sensor through a short-circuit input end, and using the residual current value to correct an initial offset of the quantum current sensor;

[0035] In a sensitivity calibration mode, a standard current signal of a preset range point is injected into the system, and a sensitivity calibration coefficient is calculated and generated based on a least square method by comparing the corresponding relationship between the standard current signal and the quantum measurement signal;

[0036] In a temperature compensation mode, a mapping relationship matrix between temperature and sensitivity is established according to the external environmental temperature change trend, and is used to correct the measurement error caused by temperature drift in real time.

[0037] As a preferred scheme of the measurement and calibration system of the quantum current sensor, wherein: the standard current source includes a plurality of current source modules covering different current ranges, each current source module is configured in a segmented manner, and is used to realize the output of a 10 mu A to 70 kA current range.

[0038] The present application provides a measurement and calibration method of a quantum current sensor.

[0039] To solve the above technical problems, the present application provides the following technical scheme: a measurement and calibration method of a quantum current sensor, comprising:

[0040] The direct current / alternating current standard current source in the standard calibration system is controlled to output a standard current signal in a 10 mu A to 70 kA range, and is introduced into the input end of the standard current sensor and the quantum current sensor at the same time;

[0041] The standard current sensor measures the standard current signal to generate a standard measurement signal, and the signal processing system records the value of the signal;

[0042] The microwave system is started, a microwave signal of a set frequency is generated through a phase-locked loop and a direct digital frequency synthesis technology, and is amplified by a microwave power amplifier and applied to the quantum current sensor, so as to excite the electronic spin state energy level structure of the internal diamond NV color center of the quantum current sensor;

[0043] The optical system is started, the laser emits linearly polarized laser, which is divided into reference light and sensing light by a beam splitter, the sensing light is introduced into the quantum current sensor through a circulator, excites the quantum state to generate a fluorescence signal, and the fluorescence signal is filtered by a filter after the excitation light, and is converted into an electrical signal by a photodetector;

[0044] The output signal of the standard current sensor and the photoelectric detector is input into a signal conditioning module in a signal processing system, and after cross resistance amplification, filtering and gain control, the signal is sent to a data acquisition module for analog-to-digital conversion;

[0045] In the analysis processing module, the collected digital signal is subjected to sliding average processing, spectrum analysis, linear fitting and temperature drift modeling to obtain error parameters between the quantum measurement signal and the standard measurement signal.

[0046] Based on the error parameters, calibration data including zero correction value, sensitivity calibration coefficient and temperature drift correction matrix are generated, and the calibration data is fed back to the quantum current sensor control unit for real-time adjustment of the measurement output, realizing linear compensation, sensitivity correction and temperature drift calibration of the quantum current sensor.

[0047] The application provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the measurement and calibration system of the quantum current sensor when executing the computer program.

[0048] The application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the steps of the measurement and calibration system of the quantum current sensor.

[0049] The application has the advantages that high-precision measurement and calibration of the quantum current sensor in the full range can be realized, and the stability and reliability of the quantum current sensor in complex application scenarios can be improved.

[0050] The quantum current sensor with diamond NV color center as the core is introduced, and the excitation and control of quantum state energy level are realized by combining the optical system and the microwave system, which can accurately perceive the magnetic field change caused by the applied current, realize non-contact and high-sensitivity quantum current measurement response.

[0051] The microwave signal source based on the phase-locked loop and the direct digital frequency synthesis technology and the microwave power amplifier with automatic gain adjustment capability are used to build the microwave system, realize accurate output and stable amplification of the microwave signal, ensure accurate and efficient control of the quantum state energy level, and reduce the interference of environmental noise on the quantum response frequency.

[0052] The signal processing system realizes complete processing links such as transimpedance amplification, filtering and shaping, analog-to-digital conversion, digital demodulation, spectrum analysis and error modeling of analog signals. The system supports synchronous acquisition and comparison of quantum signals and standard signals, automatically extracts error information including zero drift, sensitivity deviation and temperature influence, and outputs structured calibration parameters. The parameters can be fed back to the quantum current sensor in real time to realize adaptive performance correction.

[0053] Combined with the data display and control function of the host computer, the system not only supports visual presentation of measurement data, but also can automatically switch to different calibration modes, including zero calibration, sensitivity correction and temperature compensation, according to user settings, to realize a self-calibration mechanism for quantum current measurement in a dynamic environment. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0055] Figure 1 The overall structure diagram of a measurement and calibration system of a quantum current sensor is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0056] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings in the specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.

[0057] Embodiment 1, refer to Figure 1 For an embodiment of the present application, the embodiment provides a measurement and calibration system of a quantum current sensor, comprising:

[0058] The standard calibration system comprises a direct current / alternating current standard current source, a standard current sensor and a quantum current sensor;

[0059] The microwave system is used to apply a microwave signal of a set frequency to the quantum current sensor to excite or control the internal quantum state energy level structure thereof;

[0060] The optical system is used to excite the quantum state in the quantum current sensor and obtain a related optical response signal;

[0061] A signal processing system is configured to collect and analyze output signals of the standard current sensor and the quantum current sensor respectively, and generate calibration data for error compensation or performance correction of the quantum current sensor.

[0062] In an embodiment of the present application, the measurement and calibration system of the quantum current sensor comprises a standard calibration system, which comprises a DC / AC standard current source, a standard current sensor and a quantum current sensor. The standard current source is configured to output a standard current signal in a predetermined current range, which is input to the standard current sensor and the quantum current sensor simultaneously. The standard current sensor is configured to provide a high-precision current measurement reference, and the quantum current sensor outputs a quantum measurement signal corresponding to the standard current signal. The system realizes comparison calibration of the quantum current sensor based on the error between the outputs of the two.

[0063] In an optional embodiment of the present application, the standard current source is a multi-range standard current source array covering a current range of 10 μA to 70 kA, which adopts a segmented configuration. A low current range is provided by a high-precision module such as ATS-2100CF, a medium current is output by 2280S-32-6, and a high current range is borne by a customized DPS10-10000 and a customized current source. The output precision of all modules is better than 0.05% FS, and they have the characteristics of continuous adjustability and high temperature stability. The standard current sensor is composed of multiple high-precision current sensing modules, each of which covers a different current interval and constitutes a segmented detection unit. Each module is enabled according to the current range by automatic switching to meet the requirement of full-range high-accuracy detection.

[0064] In a preferred embodiment of the present application, the standard current sensor of the standard calibration system is of a closed-loop structure, which supports simultaneous and accurate detection of DC and AC signals. The sensor response bandwidth covers DC to 50 kHz, and has a measurement precision of 0.01% FS to 0.05% FS (according to range allocation). The system adopts a soft switching strategy when switching the range to avoid data jump, and introduces a redundancy error mechanism to ensure that the standard calibration path is continuous, stable and reliable.

[0065] The preferred technical solution has the beneficial effects that by constructing a standard current source with multi-range coverage and high-precision output, and a standard current sensor array with high linearity and high repeatability, a standard measurement reference system with traceability and strong stability is established, so that the quantum current sensor can realize closed-loop comparison and accurate calibration in the scene from micro-current to high-current. This calibration method has the advantages of wide adaptation, strong traceability and small temperature drift, which significantly improves the engineering adaptability and measurement reliability of the quantum current sensor.

[0066] In an embodiment of the present application, the measurement and calibration system of the quantum current sensor comprises a microwave system for applying microwave signals of a set frequency to the quantum current sensor to excite or regulate the quantum state energy level structure inside the quantum current sensor. The microwave signal serves as an energy source for driving the electronic spin state transition of the diamond NV color center, and is an indispensable part of quantum state regulation. The stability and accuracy of the microwave signal directly affect the accuracy of the quantum measurement signal.

[0067] In an optional embodiment of the present application, the microwave system comprises a microwave signal source, a microwave power amplifier and a microwave transmission path. The microwave signal source is constructed based on a phase-locked loop (PLL) combined with a direct digital frequency synthesizer (DDS) structure, which can realize high stability and low phase noise of the microwave frequency output, and provide a high-precision reference clock through a crystal oscillator. The microwave power amplifier uses GaN (gallium nitride) based devices, which are amplified to a power level sufficient to drive atomic transitions through multi-stage gain design. The microwave power amplifier has built-in automatic level control and temperature compensation circuits to improve the stability of the system output. The microwave transmission path uses coaxial cable or microstrip line structure, combined with impedance matching design and electromagnetic shielding measures, to efficiently transmit the microwave signal to the sensitive area inside the quantum current sensor.

[0068] In a preferred embodiment of the present application, the microwave system further combines a dual-frequency modulation technique and a digital regulation circuit, which can dynamically switch the modulation frequency to suppress environmental magnetic disturbance noise, and integrates a microwave bridge and an integrated radiation structure to realize a spatially consistent alternating magnetic field. The microwave control module can also be linked with a temperature sensing system to automatically adjust the output power based on environmental fluctuations to maintain the constant excitation conditions of the quantum state, thereby ensuring the repeatability and stability of the quantum measurement signal.

[0069] The beneficial effects of the preferred technical solution are: by constructing a high-precision adjustable microwave system, the NV color center spin state in the quantum current sensor is accurately excited and controlled, and the low phase noise and high power stability of the amplification output significantly enhance the signal-to-noise ratio of the quantum state readout signal. At the same time, the system has the characteristics of strong anti-environmental interference ability, good output consistency and excellent dynamic adjustment ability, which further improves the stability and practicality of the overall measurement system, and provides reliable protection for quantum current measurement under complex working conditions.

[0070] In an embodiment of the present application, the measurement and calibration system of the quantum current sensor comprises an optical system for exciting the quantum state in the quantum current sensor and obtaining the related optical response signal. This system relies on the optical properties of the diamond NV color center, uses the principle of laser excitation and fluorescence detection, and realizes optical readout of the quantum spin state change under external microwave excitation, which is an important link in the quantum current measurement chain.

[0071] In an optional embodiment of the present application, the optical system comprises a laser, a beam splitter, a circulator, a filter and a photodetector. The laser is a DFB semiconductor laser, which outputs linearly polarized laser with stable narrow linewidth (<0.1 nm) as the quantum state excitation light source. The beam splitter is used to divide the excitation light output by the laser into two paths in a predetermined ratio (e.g. 90% excitation light and 10% reference light), and the sensing light passes through the circulator into the quantum current sensor, interacts with the NV color center to generate a fluorescence signal with current information, and then is guided back by the circulator and passes through the filter to filter out the excitation light band and only retain the fluorescence signal, which is finally received by the avalanche photodiode (APD) photodetector and converted into an electrical signal.

[0072] In a preferred embodiment of the present application, the optical system adopts a non-reciprocal circulator to construct a unidirectional optical path transmission structure to reduce the influence of reflection interference on the stability of the optical signal; the beam splitter is made by a fused taper process to achieve high-precision beam splitting ratio control; the filter is a narrow-band interference type bandpass filter with a center wavelength located in the NV color center fluorescence band (637-800 nm) to effectively suppress the background excitation light. The photodetector adopts a high-gain APD module with low-noise amplification and high-speed response characteristics. The entire optical path structure is compact and stable, and can be embedded in a packaged quantum measurement head to realize remote non-contact measurement.

[0073] The beneficial effects of the preferred technical solution are that the optical system can significantly improve the quantum state readout efficiency and signal-to-noise ratio, reduce background interference and enhance the response capability of the system to weak optical signals through precise design of the laser excitation path, fluorescence collection path and optical signal conversion path; at the same time, the unidirectionality and compact structure of the optical path improve the robustness of the system in actual complex environments, ensuring stable output of quantum current measurement data and laying a solid foundation for high-precision and wide dynamic range current detection.

[0074] In an embodiment of the present application, the measurement and calibration system of the quantum current sensor comprises a signal processing system for respectively collecting the output signals of the standard current sensor and the quantum current sensor and performing analysis and processing to generate calibration data for error compensation or performance correction of the quantum current sensor. This system constructs a complete signal link for analog signal conditioning, digital acquisition, intelligent analysis and data communication.

[0075] In an optional embodiment of the present application, the signal processing system comprises a signal conditioning module, a data acquisition module, an analysis processing module and a communication module. The signal conditioning module performs transimpedance amplification, gain adjustment and filtering on weak analog signals from the standard current sensor and the photodetector; the data acquisition module synchronously samples and analog-to-digital converts the conditioned signals; the analysis processing module performs operations including sliding average, spectral analysis, linear fitting and the like, thereby extracting the response characteristics and error information of the quantum current sensor; and the communication module transmits the calibration data to an upper computer or a remote control unit for storage and further processing after packaging.

[0076] In a preferred embodiment of the present application, the signal conditioning module uses a low-noise transimpedance amplifier (such as ADA4530-1) to realize high-gain conversion of nA-level photocurrent, and cooperates with a programmable gain amplifier (PGA280) and a fourth-order Butterworth low-pass filter to form a front-end processing capability of 120dB dynamic range; the data acquisition module uses dual-channel high-resolution analog-to-digital converters, such as ADS127L11 (24-bit, 512kSPS) and ADS54J60 (16-bit, 1GSPS), to respectively acquire optical and microwave signals, ensuring time synchronization; the analysis processing module is based on FPGA architecture, and builds algorithm modules of sliding filtering, DDC (digital down conversion), FFT, baseline calibration, linear fitting, temperature drift modeling and the like, and after processing, sends into DDR cache through AXI bus; the communication module selects FT600Q USB 3.0 controller to build a high-speed data communication link with a simplified frame structure, each frame containing a timestamp, a channel identifier and compressed data, and the actual measured bandwidth can reach 320MB / s; and the upper computer software platform supports waveform display, error analysis and calibration coefficient feedback.

[0077] The preferred technical solution has the beneficial effects that the signal processing system builds a full-process signal channel from high-precision signal conditioning to high-speed digital acquisition to intelligent error analysis and feedback control, has high resolution, high bandwidth and high robustness, and can realize stable acquisition and rapid processing of weak signals; the multi-algorithm collaborative mechanism guarantees high-precision extraction of calibration parameters, especially under complex working conditions (such as high voltage and temperature drift), and can still maintain the consistency and repeatability of system measurement, thereby effectively improving the application reliability and measurement accuracy of the quantum current sensor.

[0078] In an alternative embodiment of the present application, the standard current sensor comprises a plurality of current sensing modules, each module covering a different current range, for example 10 μΑ to 1 mA, 1 mA to 1 A, 1 A to 10 A, 10 A to 100 A, 100 A to 1 kA, 1 kA to 70 kA. Each current sensing module employs a sensor element with matching accuracy level, including a current transformer, an open-close Hall element or a high-precision shunt. The modules are switched by program control to achieve segmented measurement of the standard current signal, with the function of automatic selection of the range to ensure consistent and rapid response of the current detection output in the entire current range.

[0079] In a preferred embodiment of the present application, the microwave system further comprises a microwave transmission path, a microwave signal source generates a signal of a set frequency, which is amplified by a microwave power amplifier and transmitted to the microwave coupling structure of the quantum current sensor through an impedance-matched microwave transmission line. The coupling structure can be a patch microstrip antenna or a dipole antenna, which is arranged near the quantum sensitive region to ensure uniform distribution and controllable field strength of the microwave field in the excitation region. The transmission path is designed with a microwave matching network at both ends to control the standing wave ratio within 1.2, thereby ensuring efficient coupling of microwave energy to the target region to drive the electronic spin transition of the NV color center.

[0080] In a preferred embodiment of the present application, the analysis processing module in the signal processing system is used to perform comparison processing on the standard current signal and the quantum measurement signal. For the optical channel signal, sliding average denoising processing, baseline calibration and drift trend identification are applied; the microwave channel data is extracted by digital down-conversion and fast Fourier transform to obtain the NV color center resonance frequency shift; the comparison analysis uses the least squares method to fit the standard current and the quantum response to obtain the sensitivity slope and the linear error index, and generates a calibration factor based on which to feedback to the sensor control system for real-time adjustment of the measurement parameters.

[0081] In an alternative embodiment of the present application, the host computer system supports multi-mode calibration strategies, including zero-point calibration, sensitivity calibration and temperature compensation calibration. In the zero-point calibration mode, the control system short-circuits the input end, records the residual current value of the standard current sensor, and corrects the zero-point drift of the quantum current sensor accordingly. In the sensitivity calibration mode, a set of step-point current signals are injected, and the output results are collected to generate sensitivity correction parameters by linear regression fitting. In the temperature compensation mode, the quantum current response values are recorded at different temperature environments to construct a functional mapping relationship between temperature and sensitivity, forming a temperature drift correction matrix to realize real-time compensation of measurement errors under variable temperature conditions.

[0082] In a preferred embodiment of the present application, the standard current source is composed of multiple modules, respectively covering the micro-current, small-current, medium-current and large-current sections, typically configured as 10 μA to 100 mA, 100 mA to 10 A, 10 A to 10 kA and 10 kA to 70 kA. Each current source module has high stability and high precision output capability, and is connected to the system control unit through a unified control interface to realize smooth and continuous current regulation and rapid switching in the full range. The power module has current slow-rising start, overload protection and remote monitoring function, to ensure stable and reliable reference current under different calibration tasks.

[0083] In a preferred embodiment of the present application, after the parameter extraction and error modeling are completed, the host computer system automatically generates a calibration parameter table containing zero point offset value, sensitivity slope and temperature correction coefficient. The parameter table is fed back to the quantum current sensor control unit through the high-speed bus to realize real-time correction and optimization of the quantum measurement signal. The feedback mechanism supports timing or event triggering mode to ensure that the quantum current sensor always maintains high precision output in a variable environment.

[0084] Embodiment 2 is an embodiment of the present application, which provides a measurement and calibration system for a quantum current sensor based on the previous embodiment, comprising:

[0085] A closed-loop calibration reference is formed by constructing a high-stable direct-current large-current standard source (10 μA-70 kA range) and a high-precision standard current sensor (covering the same range) to realize the static parameter test and dynamic calibration of linearity, sensitivity, etc. by using the data acquisition system to compare and analyze the output of the standard / sensor to be tested. The optical system is based on the study of NV color center spectral transition mechanism, and the accurate excitation and control of diamond NV color center electron spin energy level are realized by optimizing the selection of laser source and optical components (including laser input module, photoelectric conversion module, optical splitter and circulator). The single sideband signal modulation technology is used to suppress interference, and the microwave bridge and radiation structure are designed based on the transmission line theory to ensure the accurate generation of alternating magnetic field, and the spin state control is completed. The signal processing module includes a front-end signal conditioning module, a data acquisition module, a processing control core, a transmission module and a host computer to form a complete signal chain. Through the data obtained by the host computer, real-time comparison and analysis are realized to realize the static performance test of linearity compensation, sensitivity correction, etc. Real-time calibration of quantum current sensor is realized.

[0086] Standard calibration system: the standard calibration system of the quantum current sensor includes a DC / AC standard current source, a quantum sensor and a standard current sensor.

[0087] DC / AC standard current source: Current source is the core device of current test system, its precision directly determines the precision of the whole measurement system. Therefore, the ATS-2100CF (10 μA-100 mA), 2280S-32-6 (100 mA-10 A), DPS10-10000 (10 A-10 kA), custom (10 kA-70 kA) high-stable DC large current standard source is constructed. The precision is less than or equal to 0.05% FS, the current is continuously smooth and adjustable, and the working temperature is-10℃-50℃

[0088] Quantum current sensor: The measured quantum current sensor.

[0089] Standard current sensor: Select high-precision current sensor standard current sensor. High-precision standard current sensor adopts multiple high-precision current sensors with different ranges (covering 10 μA-70 kA range, which can be realized in segments and devices), and the precision is 0.01% FS-0.05% FS (determined according to the range) to provide high-reliability current detection for closed-loop calibration platform.

[0090] Microwave system: The microwave system of the quantum current sensor mainly consists of a microwave source and a microwave power amplifier. When the system is working, the microwave source generates electromagnetic waves of a specific frequency, which is amplified by the power amplifier and acts on the atomic ensemble in the gas chamber. The magnetic field generated by the measured current changes the atomic energy level splitting (Zeeman effect), and by detecting the resonance frequency shift of the interaction between microwave and atom, the current value can be inverted. This system uses double-frequency modulation technology to eliminate environmental magnetic field interference, and cooperates with a lock-in amplifier to realize μA level resolution, which is suitable for complex scenes such as high-voltage power grids.

[0091] Microwave source: Generate high-stability, low-phase-noise microwave signals. Adopting the architecture of direct digital frequency synthesis (DDS) combined with phase-locked loop (PLL), the reference clock is provided by crystal oscillator, and the digitally synthesized microwave signal can be accurately tuned.

[0092] Microwave power amplifier: Amplify the microwave signal to a power sufficient to drive atomic transition. Adopting GaN-based microwave power amplifier, gain is realized through multi-stage amplification structure, and built-in automatic level control and temperature compensation circuit ensures output stability.

[0093] Optical system: quantum current sensor optical system includes, laser, beam splitter, circulator, optical filter, photodetector. The operation of quantum current sensor optical system is based on Faraday magneto-optical effect. When the system starts, the laser emits high-stable linearly polarized light, which is divided into reference light and sensing light by the beam splitter. The sensing light enters the magnetic sensitive optical fiber through the circulator, and the magnetic field generated by the measured current makes the light polarization plane rotate, and the rotation angle is proportional to the current intensity. The light signal carrying the magnetic field information returns through the circulator, and the reference light passes through the narrow-band optical filter to eliminate environmental noise, and finally the high-sensitivity photodetector converts it into an electrical signal, and the current is measured by demodulating the polarization rotation amount.

[0094] Laser: Provide monochromatic coherent light source. DFB semiconductor laser is used, and stimulated radiation is generated by current injection to activate the active region, which needs to maintain a narrow line width (<0.1nm) to maintain quantum coherence;

[0095] Beam splitter: light path distribution, proportional beam splitting (such as 90% excitation / 10% monitoring). The splitting ratio is accurately adjusted by controlling the fusion length and stretching speed;

[0096] Circulator: realize one-way transmission of optical signal, use Faraday optical rotation effect (non-reciprocity), port 1→2→3 light path loss <0.5dB;

[0097] Optical filter: spectral filtering, extract NV color center fluorescence (637-800nm). Through band-pass filtering, excitation light noise is suppressed;

[0098] Photodetector: photoelectric conversion, avalanche photodiode (APD) amplifies weak light signal through multiplication effect.

[0099] Signal processing system includes: front-end signal conditioning module. The photovoltaic channel uses an ultra-low noise transimpedance amplifier (such as ADA4530-1) to convert nA-level photocurrent into a voltage signal, and cooperates with a programmable gain amplifier (PGA280) and a fourth-order Butterworth anti-aliasing filter to realize a 120dB dynamic range. The microwave channel passes through an HMC788 buffer and an HMC363 frequency divider to reduce the GHz signal to the order of 100MHz, while retaining the phase information and matching the ADC input range;

[0100] Data acquisition module. A dual-channel synchronous sampling architecture is used, and ADS54J60 (16-bit 1GSPS) is used to collect microwave signals and ADS127L11 (24-bit 512kSPS) to process photovoltaic signals;

[0101] Signal processing module. Real-time processing is realized based on FPGA. In the analog signal conditioning stage, the transimpedance amplification of the photodetector output is implemented, and a fourth-order Butterworth low-pass filter is used for logarithmic amplification and band-pass filtering of the microwave source signal; In the analog-to-digital conversion link, a double-channel synchronous sampling ADC (16-bit resolution, sampling rate 5MS / s) is used, and the data is written into the FPGA cache area through the SPI interface; The digital signal processing part constructs a parallel pipeline in the FPGA, and the photoelectric channel realizes the sliding average filtering and baseline calibration algorithm, the microwave channel completes the digital down conversion (DDC) and 128-point FFT spectrum analysis, and the processing result is transmitted to the DDR3 cache through the AXI bus, and the data packaging (including timestamp, channel ID, IQ data) is completed;

[0102] Communication module. The communication module uses FT600Q USB3.0 controller, and the transmission protocol is customized as a simplified frame structure: each frame contains 4 bytes of timestamp, 2 bytes of channel identification and 24 bytes of payload (compressed spectral amplitude / phase data), and the actual measured continuous transmission rate reaches 320MB / s;

[0103] Host computer. Data receiving: receiving the signal data uploaded by the communication module. Display and analysis: real-time display and analysis of the received signal data, such as waveform display, spectrum analysis, feature extraction, etc.

[0104] Calibration method: the closed-loop measurement calibration system provides an accurate feedback signal for the quantum current sensor, which is crucial for ensuring the high precision and stability of the quantum current sensor. The calibration of the current can be realized by comparing the current error between the to-be-measured sensor (i.e. the quantum current sensor) and the calibration sensor (i.e. the high-precision current sensor).

[0105] First, a standard current environment is established, and a precise current source is used to output step currents of different ranges, while recording the readings of the calibration sensor and the to-be-calibrated quantum sensor. The calibration includes three parts: during zero-point calibration, the input end is short-circuited, and the residual current value of the calibration sensor is used to correct the zero-point offset of the quantum sensor; during sensitivity calibration, the standard current is injected at the 50% range point, and the linear coefficient of the quantum sensor output and the calibration value is fitted by the least squares method; temperature compensation calibration needs to be carried out in a variable temperature box, and a temperature-sensitivity correction matrix is established. The calibration parameters include: linearity error, repeatability error, temperature coefficient.

[0106] Embodiment 3 is an embodiment of the present application, which provides a measurement and calibration method for a quantum current sensor, comprising:

[0107] The direct current / alternating current standard current source in the standard calibration system is controlled to output a standard current signal in the range of 10μA to 70kA, and simultaneously introduced into the input end of the standard current sensor and the quantum current sensor;

[0108] The standard current signal is measured by a standard current sensor to generate a standard measurement signal, and the value of the signal is recorded by a signal processing system;

[0109] The microwave system is started, a microwave signal of a set frequency is generated by a phase-locked loop and a direct digital frequency synthesis technology, amplified by a microwave power amplifier, and applied to the quantum current sensor to excite the electronic spin state energy level structure of the internal diamond NV color center of the quantum current sensor;

[0110] The optical system is started, the laser emits linearly polarized laser light, which is divided into reference light and sensing light by a beam splitter, the sensing light is introduced into the quantum current sensor through a circulator, excites the quantum state to generate a fluorescence signal, and the fluorescence signal is converted into an electrical signal by a photodetector after the excitation light is filtered out by an optical filter;

[0111] The output signals of the standard current sensor and the photodetector are input into a signal conditioning module in the signal processing system, and after cross resistance amplification, filtering and gain control, they are sent to a data acquisition module for analog-to-digital conversion;

[0112] The digital signals collected in the analysis and processing module are subjected to sliding average processing, spectral analysis, linear fitting and temperature drift modeling to obtain error parameters between the quantum measurement signal and the standard measurement signal;

[0113] Based on the error parameters, calibration data including zero correction value, sensitivity calibration coefficient and temperature drift correction matrix are generated, and the calibration data are fed back to the quantum current sensor control unit for real-time adjustment of the measurement output, realizing linear compensation, sensitivity correction and temperature drift calibration of the quantum current sensor.

[0114] The embodiment also provides an electronic device suitable for the case of the quantum current sensor measurement and calibration system, including a memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions to realize the quantum current sensor measurement and calibration system as described in the above embodiment.

[0115] The embodiment also provides a storage medium having a computer program stored thereon, which is executed by a processor to realize the quantum current sensor measurement and calibration system as described in the above embodiment.

[0116] The storage medium proposed in the embodiment and the quantum current sensor measurement and calibration system proposed in the above embodiment belong to the same inventive concept, and the technical details not described in detail in the embodiment can be referred to the above embodiment, and the embodiment and the above embodiment have the same beneficial effects.

[0117] From the above description of the embodiments, those skilled in the art can clearly understand that the present application can be implemented by means of software and necessary universal hardware, and of course can also be implemented by hardware, but in many cases the former is a better implementation. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a floppy disk, a ROM, a RAM, a FLASH, a hard disk, or an optical disc, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods of various embodiments of the present application.

[0118] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application but not limit the present application, and although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A measurement and calibration system for a quantum current sensor, characterized in that: include, Standard calibration system, including DC / AC standard current source, standard current sensor and quantum current sensor; A microwave system for applying a microwave signal of a set frequency to the quantum current sensor to excite or regulate the quantum state energy level structure inside the sensor; an optical system for exciting quantum states in the quantum current sensor and acquiring related optical response signals; The signal processing system is used to respectively collect the output signals of the standard current sensor and the quantum current sensor, and perform analysis and processing to generate calibration data for error compensation or performance correction of the quantum current sensor.

2. A quantum current sensor measurement and calibration system as claimed in claim 1, characterized in that: The standard current source is used to output a standard current signal within a predetermined current range, the standard current sensor is used to measure the standard current signal, and the quantum current sensor is used to receive the standard current signal and output a corresponding quantum measurement signal to achieve comparison and calibration between the standard current signal and the quantum measurement signal; The standard current sensor includes a plurality of current sensing modules for performing signal detection corresponding to different current ranges, and the plurality of current sensing modules are configured in a segmented manner to form a standard current measurement unit.

3. A quantum current sensor measurement and calibration system as claimed in claim 2, characterized in that: The quantum current sensor includes a sensitive unit having a diamond NV color center structure. Under the joint action of the microwave system and the optical system, the sensitive unit forms an optical response for outputting a quantum measurement signal through electron spin state transition.

4. A quantum current sensor measurement and calibration system as claimed in claim 3, characterized in that: The microwave system includes a microwave signal source for generating a microwave signal of a set frequency based on a phase-locked loop and direct digital frequency synthesis technology; a microwave power amplifier, connected to the microwave signal source, for amplifying the microwave signal to a power level sufficient to drive atomic transitions within the quantum current sensor; The microwave transmission path is used to transmit the amplified microwave signal to the quantum current sensor to induce energy level splitting or transition of the internal spin state thereof, so as to realize quantum state regulation related to current intensity.

5. A quantum current sensor measurement and calibration system as claimed in claim 4, characterized in that: The optical system includes a laser configured to output linearly polarized laser light; A beam splitter, an input end of which is connected to the laser and is used to split the linearly polarized laser into reference light and sensing light; a circulator, one end of which is connected to the optical splitter and is used to guide the sensing light into the quantum current sensor and back; an optical filter connected to the output end of the circulator and configured to filter out the excitation light component in the return light; The photodetector is connected to the output end of the optical filter and is used for converting the filtered optical signal into an electrical signal.

6. A quantum current sensor measurement and calibration system as claimed in claim 5, characterized in that: The signal processing system includes a signal conditioning module for performing transimpedance amplification, filtering, and gain control on the analog signals output by the standard current sensor and the photodetector to adapt to subsequent data acquisition; A data acquisition module, connected to the signal conditioning module, for synchronously converting the conditioned analog signal into a digital signal; An analysis and processing module, connected to the data acquisition module, for performing sliding average, spectrum analysis, and linear fitting algorithm operations on the digital signal to extract performance indicators of the quantum current sensor; The communication module is used to transmit the calibration data or measurement results processed by the analysis and processing module to the host computer for storage and display.

7. A quantum current sensor measurement and calibration system according to claim 6, characterized in that: The signal processing system further includes a host computer system, which is configured to receive the calibration data transmitted by the communication module and perform the following operations: Perform waveform display, spectrum analysis and parameter extraction on the received data; According to the error relationship between the standard current signal and the quantum measurement signal, calibration parameters for linearity compensation, sensitivity correction and temperature drift correction are calculated and output; The calibration parameters are fed back to the quantum current sensor to dynamically optimize its measurement performance.

8. A quantum current sensor measurement and calibration system as claimed in claim 7, characterized in that: The host computer system executes parameter correction strategies according to different calibration scenarios, including, in zero-point calibration mode, obtaining the residual current value of the standard current sensor through the short-circuit input terminal and using it to correct the initial offset of the quantum current sensor; In the sensitivity calibration mode, a standard current signal at a preset range point is injected into the system, and the correspondence between the standard current signal and the quantum measurement signal is compared based on the least squares method to calculate and generate the sensitivity calibration coefficient. In temperature compensation mode, a mapping relationship matrix between temperature and sensitivity is established based on the external ambient temperature change trend to correct the measurement error caused by temperature drift in real time.

9. A quantum current sensor measurement and calibration system as claimed in claim 8, characterized in that: The standard current source includes a plurality of current source modules covering different current ranges, and each current source module is configured in a segmented manner to achieve output in a current range of 10 μA to 70 kA.

10. A method for measuring and calibrating a quantum current sensor, using a system for measuring and calibrating a quantum current sensor according to any one of claims 1 to 9, characterized in that: include: Controlling the DC / AC standard current source in the standard calibration system to output a standard current signal within the range of 10μA to 70kA, and simultaneously introducing the signal to the input terminals of the standard current sensor and the quantum current sensor; Measuring the standard current signal by a standard current sensor to generate a standard measurement signal, and recording the value of the signal by a signal processing system; The microwave system is started, and a microwave signal of a set frequency is generated through a phase-locked loop and direct digital frequency synthesis technology. After being amplified by a microwave power amplifier, it is applied to the quantum current sensor to excite the electron spin state energy level structure of the diamond NV color center inside it. The optical system is activated, and the laser emits linearly polarized laser light, which is divided into reference light and sensing light by a beam splitter. The sensing light is introduced into the quantum current sensor through a circulator, exciting its quantum state to generate a fluorescence signal. The fluorescence signal is filtered out by a filter and converted into an electrical signal by a photodetector. The output signals of the standard current sensor and the photodetector are input into the signal conditioning module of the signal processing system, and after completing transimpedance amplification, filtering and gain control, they are sent to the data acquisition module for analog-to-digital conversion; In the analysis and processing module, the collected digital signal is subjected to sliding average processing, spectrum analysis, linear fitting, and temperature drift modeling to obtain the error parameters between the quantum measurement signal and the standard measurement signal; Calibration data is generated based on the error parameters, including a zero point correction value, a sensitivity calibration coefficient, and a temperature drift correction matrix. The calibration data is fed back to the quantum current sensor control unit for real-time adjustment of its measurement output to achieve linearity compensation, sensitivity correction, and temperature drift calibration of the quantum current sensor.

Images