Quantum current sensor based on zero magnetic flux and current detection method

Abstract

The invention provides a quantum current sensor based on zero magnetic flux and a current detection method, and the sensor comprises a reverse magnetic field module which is used for generating a second magnetic field which is opposite to a first magnetic field in direction after a driving current is introduced, and the first magnetic field is generated by a to-be-detected current-carrying conductor; the auxiliary magnetic sensor and the solid-state spinning color center magnetometer are both located in a superimposed magnetic field of the first magnetic field and the second magnetic field and output a first measurement value and a second measurement value respectively; the feedback regulation module is used for providing driving current for the reverse magnetic field module, regulating and controlling the driving current according to the first measurement value until the magnetic field intensity value corresponding to the measured first measurement value is within the measuring range of the solid-state spin color center magnetometer, and regulating and controlling the driving current according to the second measurement value until the magnetic field intensity value corresponding to the measured first measurement value is within the measuring range of the solid-state spin color center magnetometer. The magnetic field intensity value corresponding to the measured second measurement value is zero; and the current calculation module is used for calculating the current value in the current-carrying conductor according to the driving current value. And high-precision measurement of wide-range current can be realized.

Description

Technical Field

[0001] The present invention relates to the field of quantum sensing, and in particular to a quantum current sensor based on zero magnetic flux and a current detection method. Background Art

[0002] Quantum sensors based on solid-state spin color centers are widely used in current measurement due to their high sensitivity and precision, becoming a key detection method in the power industry. Their detection principle relies on detecting the magnetic field generated by current, achieving ultra-high sensitivity and precision in the picotesla range. After detecting the magnetic field, the current value is calculated using the conversion relationship between magnetic field and current.

[0003] While quantum sensors are suitable for highly sensitive detection of weak magnetic fields, their limitation lies in their narrow detection range, typically ranging from a few to tens of gauss. They are less suitable for larger magnetic fields of hundreds or even thousands of gauss. Achieving high-sensitivity and high-precision detection of a wide range of magnetic fields remains a challenge. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a quantum current sensor based on zero magnetic flux and a current detection method, which are used to solve the problem of limited detection range when measuring current using solid-state spin color center quantum current sensors in the prior art.

[0005] To achieve the above objectives and other related objectives, a first aspect of the present invention provides a zero-flux quantum current sensor, comprising: A reverse magnetic field module, configured to generate a second magnetic field in a direction opposite to the first magnetic field after a driving current is applied, wherein the first magnetic field is generated by the current-carrying conductor to be measured; The auxiliary magnetic sensor and the solid-state spinning color center magnetometer are both located in the superimposed magnetic field of the first magnetic field and the second magnetic field, and are used to measure the superimposed magnetic field and output a first measurement value and a second measurement value respectively; the measurement range of the auxiliary magnetic sensor is greater than the measurement range of the solid-state spinning color center magnetometer; a feedback regulation module, configured to provide a driving current to the reverse magnetic field module, and regulate the provided driving current according to the first measurement value until the magnetic field intensity value corresponding to the measured first measurement value is within the range of the solid-state spinning color center magnetometer; and then regulate the provided driving current according to the second measurement value until the magnetic field intensity value corresponding to the measured second measurement value is zero, and finally obtain the driving current value provided to the reverse magnetic field module; The current calculation module is used to calculate the current value in the current-carrying conductor according to the driving current value.

[0006] Furthermore, the reverse magnetic field module includes an open magnetic ring and a coil wound on the outer surface of the magnetic ring. A driving current is passed through the coil, and a current-carrying conductor passes through the center of the magnetic ring. Both the auxiliary magnetic sensor and the solid-state spinning color center magnetometer measure the magnetic field in the open air gap of the magnetic ring.

[0007] Furthermore, the feedback regulation module includes a controller, a current signal processing module, and a driving module connected in sequence; the controller is also connected to the output end of the auxiliary magnetic sensor and the solid-state spinning color center magnetometer, for receiving the first measurement value and the second measurement value, and the controller is also connected to the driving module and the current calculation module, for controlling the driving module to provide a driving current to the reverse magnetic field module, and transmitting a current regulation signal to the current signal processing module, and obtaining the driving current value provided to the reverse magnetic field module when the magnetic field strength value corresponding to the measured second measurement value is zero; after the current signal processing module processes the current regulation signal, it transmits it to the driving module to adjust the current it provides to the reverse magnetic field module.

[0008] Furthermore, the driving module includes a driving power supply and a MOS tube. The driving power supply is connected to a controller and provides a DC voltage to the MOS tube and the reverse magnetic field module under the control of the controller. The MOS tube and the reverse magnetic field module form a series circuit. The current signal processing module is also connected to the MOS tube and transmits a current regulation signal to the MOS tube to regulate the current therein.

[0009] Furthermore, the driving power supply includes one or more power supply circuits, each power supply circuit includes a DC output power supply, an on-off switch, a voltage conversion module, and an anti-leakage module connected in sequence; the controller is also connected to the on-off switch and the voltage conversion module in each power supply circuit, and starts the voltage output of the corresponding power supply circuit by controlling the on-off switch, and controls the voltage output of this power supply circuit by regulating the voltage conversion module; when multiple power supply circuits are included, each power supply circuit corresponds to a different output voltage.

[0010] Furthermore, it also includes a current detection module, which is connected to the reverse magnetic field module and is used to detect the current flowing into the reverse magnetic field module to form a current measurement signal. It is also connected to the feedback regulation module and is used to transmit the current measurement signal to the feedback regulation module to obtain a current value. The feedback regulation module also compares this current value with the driving current value provided to the reverse magnetic field module to determine whether the operation of the feedback regulation module is normal.

[0011] Furthermore, the solid-state spin color center magnetometer includes a magnetically sensitive probe, an optical detection unit, a microwave unit, and a control and calculation unit; the magnetically sensitive probe contains a solid-state spin color center for sensing a magnetic field; the optical detection unit is used to irradiate excitation light onto the magnetically sensitive probe and detect fluorescence generated by the magnetically sensitive probe, wherein the excitation light is used to excite the solid-state spin color center to generate fluorescence; the microwave unit is used to radiate microwaves onto the magnetically sensitive probe; the control and calculation unit is used to control the frequency of microwaves radiated by the microwave unit to the magnetically sensitive probe, and to collect the fluorescent electrical signal from the optical detection unit to obtain the resonant frequency, and calculate the magnetic field intensity value or the magnetic field component value along one of the color center axes based on the resonant frequency, and output this magnetic field intensity value or the magnetic field component value along one of the color center axes as a second measurement value to the feedback adjustment module.

[0012] Furthermore, the auxiliary magnetic sensor is a Hall sensor or a magnetoresistive sensor.

[0013] Furthermore, the solid-state spin color center is one of a diamond nitrogen vacancy color center, a diamond germanium vacancy color center, a diamond silicon vacancy color center, a silicon carbide silicon-carbon double vacancy color center, a silicon carbide silicon vacancy color center, and a hexagonal boron nitride boron vacancy color center.

[0014] To achieve the above-mentioned and other related objectives, a second aspect of the present invention provides a current detection method based on zero magnetic flux, comprising: Providing a driving current to a reverse magnetic field module to generate a second magnetic field in a direction opposite to the first magnetic field, wherein the first magnetic field is generated by the current-carrying conductor to be measured; The auxiliary magnetic sensor and the solid-state spinning color center magnetometer are used to detect the magnetic field formed by superposition of the first magnetic field and the second magnetic field, and a first measurement value and a second measurement value are obtained respectively; the measurement range of the auxiliary magnetic sensor is greater than the measurement range of the solid-state spinning color center magnetometer; Adjusting the provided driving current according to the first measurement value until the magnetic field strength value corresponding to the measured first measurement value is within the range of the solid-state spinning color center magnetometer, and then adjusting the provided driving current according to the second measurement value until the magnetic field strength value corresponding to the measured second measurement value is zero; The current value in the current-carrying conductor to be measured is calculated according to the driving current value provided to the reverse magnetic field module.

[0015] As described above, the zero-flux quantum current sensor and current detection method of the present invention have the following beneficial effects: The present invention sets a reverse magnetic field module to generate a reverse magnetic field, and uses an auxiliary magnetic sensor and a solid-state spin color center magnetometer to measure the superimposed magnetic field of the current-carrying conductor to be measured and the reverse magnetic field module; utilizing the advantage of the large-scale detection of the auxiliary magnetic sensor, first, according to the first measurement value detected by it, the driving current provided to the reverse magnetic field module is regulated until the magnetic field intensity value corresponding to the first measurement value is within the range of the solid-state spin color center magnetometer, at this time, the advantages of high sensitivity and high precision of the solid-state spin color center magnetometer are utilized to measure the weak magnetic field, and the driving current provided to the reverse magnetic field module is regulated by the second measurement value until the magnetic field intensity value corresponding to the second measurement value is zero, and finally, the current value in the current-carrying conductor to be measured is calculated according to the driving current value provided to the reverse magnetic field module. It can be seen that based on the feedback regulation technology for achieving zero magnetic flux and the large-scale measurement of the auxiliary magnetic sensor and the high sensitivity and high precision measurement of the solid-state spin color center magnetometer, high sensitivity and high precision measurement of a large range of current can be ultimately achieved.

[0016] Furthermore, multiple switchable power supply circuits are set in the driving power supply, which have the function of switching the voltage output of the driving power supply in time according to the regulated current, so as to realize the control of the MOS tube power, solve the heating problem, reduce the influence of temperature drift, and thus improve the accuracy of the current supply. At the same time, the requirements for heat dissipation components are reduced, which is conducive to the miniaturization design of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Shown is a schematic diagram of the structure of the quantum current sensor of the present invention; Figure 2 Shown is an exemplary structural diagram of the quantum current sensor of the present invention; Figure 3 Shown is a structural diagram of a single power supply circuit of the driving power supply of the present invention; Figure 4 Shown is a circuit diagram of an on-off switch of the present invention; Figure 5 Shown is a circuit diagram of the voltage conversion module of the present invention; Figure 6 Shown is a circuit diagram of the coil and MOS tube of the present invention; Figure 7 Shown is an exemplary structural diagram of a solid-state spin color center magnetometer of the present invention; Figure 8 Shown is a structural diagram of multiple power supply circuits of the driving power supply of the present invention; Figure 9 Shown is a circuit diagram of a current sensing amplifier of the present invention.

[0018] Component number explanation: 1—Auxiliary magnetic sensor; 101—Magnetic sensitivity module; 102—Signal acquisition module; 1021—Instrumentation amplifier; 1022—First buffer; 1023—First analog-to-digital converter; 1024—Zero adjustment circuit; 2—Solid-state spinning color center magnetometer; 21—Magnetic sensitivity probe; 22—Optical detection unit; 221—Excitation light source; 222—Filter; 223—Photodetector; 224—Dual color plate; 23—Microwave unit; 231—Microwave source; 232—Microwave switch; 233—Microwave amplifier; 234—Microwave isolator; 235—Microwave antenna; 24—Control and calculation unit; 241—Control module; 242—Magnetic field calculation module; 3—Current-carrying conductor to be measured; 4—Reverse magnetic field module; 41—Magnetic ring; 42—Coil; 5—Feedback Regulation module; 51—controller; 52—current signal processing module; 521—digital-to-analog converter; 522—signal amplifier; 523—filter; 524—second buffer; 53—driving module; 531—driving power supply; 532—MOS tube; 533—second PMOS switching circuit; 6—current calculation module; 7—current detection module; 71—detection resistor; 72—current detection amplifier; 73—second analog-to-digital converter; 8—resistance detection module; 91—alarm; 92—indicator light; 10—power supply circuit; 11—power supply; 12—on-off switch; 121—PMOS switching circuit; 122—bleeder circuit; 123—backflow prevention circuit; 13—voltage conversion module; 131—low-voltage-dropout regulator; 132—digital potentiometer; 14—leakage prevention module. DETAILED DESCRIPTION

[0019] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0020] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0021] Example 1: Figure 1 As shown, this embodiment provides a quantum current sensor based on zero magnetic flux, including: The reverse magnetic field module 4 is used to generate a second magnetic field in the opposite direction to the first magnetic field after the driving current is applied, and the first magnetic field is generated by the current-carrying conductor 3 to be measured; The auxiliary magnetic sensor 1 and the solid-state spinning color center magnetometer 2 are both located in the superposition magnetic field of the first magnetic field and the second magnetic field, and are used to measure the magnetic field and output a first measurement value and a second measurement value respectively; the measurement range of the auxiliary magnetic sensor 1 is greater than the measurement range of the solid-state spinning color center magnetometer 2; A feedback regulation module 5 is configured to provide a driving current to the reverse magnetic field module 4, and regulate the provided driving current according to the first measurement value until the magnetic field strength value corresponding to the measured first measurement value is within the range of the solid-state spinning color center magnetometer 2, and then regulate the provided driving current according to the second measurement value until the magnetic field strength value corresponding to the measured second measurement value is zero, and finally obtain the driving current value provided to the reverse magnetic field module; The current calculation module 6 is used to calculate the current value in the current-carrying conductor according to the driving current value.

[0022] Auxiliary magnetic sensor 1 uses a sensor with a larger range than the solid-state spinning color-center magnetometer, such as a Hall effect sensor, a magnetoresistive sensor (TMR, AMR, GMR), or other sensor types capable of meeting wide-range requirements. These sensors offer the advantage of a wide measurable range, reaching hundreds or even thousands of gauss. While some can measure magnetic fields down to nanotesla, they cannot meet the requirements for higher precision measurements. Solid-state spinning color-center magnetometers can detect magnetic fields down to picotesla, offering greater sensitivity and accuracy.

[0023] This embodiment utilizes the advantages of the auxiliary magnetic sensor's large-scale detection capability. It first regulates the drive current provided to the reverse magnetic field module based on the first measurement value detected by the auxiliary magnetic sensor until the magnetic field intensity corresponding to the first measurement value is within the range of the solid-state spinning color center magnetometer. At this point, the solid-state spinning color center magnetometer's high sensitivity and high precision are utilized to measure weak magnetic fields. The second measurement value is used to regulate the drive current provided to the reverse magnetic field module until the magnetic field intensity corresponding to the second measurement value is zero. This shows that based on the feedback regulation technology for achieving zero magnetic flux, the large-scale measurement capability of the auxiliary magnetic sensor, and the high sensitivity and high precision measurement capability of the solid-state spinning color center magnetometer, high-sensitivity and high-precision measurement capability of a large current range can ultimately be achieved.

[0024] The measurement range of the solid-state spinning color center magnetometer can generally reach tens of gauss, for example, 0-30 gauss, when pursuing high precision. The specific measurement range is determined according to the required precision. When regulating the drive current based on the first and second measurement values, the first measurement value is first used to determine whether the magnetic field intensity value corresponding to it is within the measurement range of the solid-state spinning color center magnetometer. If the magnetic field intensity value corresponding to the first measurement value is within the measurement range of the solid-state spinning color center magnetometer, the provided drive current is regulated according to the second measurement value until the magnetic field intensity value corresponding to the measured second measurement value is zero. If it is not within the measurement range of the solid-state spinning color center magnetometer, the provided drive current is regulated until the magnetic field intensity value corresponding to the measured first measurement value is within the measurement range of the solid-state spinning color center magnetometer, and then the provided drive current is regulated according to the second measurement value until the magnetic field intensity value corresponding to the measured second measurement value is zero.

[0025] And judgment and regulation are performed based on the correspondence between the measured value and the magnetic field. For example, taking the TMR magnetoresistive sensor as an example, the first measured value outputted by it is a voltage value. If 1 millivolt of the output corresponds to 1 gauss of magnetic field, and the maximum range is 1000 gauss, then when the measured first measured value is 1000mV, it means that the corresponding magnetic field strength value may be above 1000Gs. At this time, if the range of the solid-state spinning color center magnetometer is 30Gs, it is necessary to provide a driving current to the reverse magnetic field module to generate a reverse magnetic field to offset the original magnetic field. If, after offsetting, the first measured value is still 1000mV, or is below 1000mV but greater than 30mV, the driving current value provided to the reverse magnetic field module is increased until the measured first measured value is below 30mV, for example, when it is adjusted to 20mV, the driving current is continued to be adjusted based on the second measured value and the previously adjusted driving current. Taking the diamond NV color center magnetometer as an example, the measured value it outputs is the calculated magnetic field intensity value. The drive current is then adjusted until the second measured value is zero. If the output is a measurement value corresponding to the magnetic field intensity value, such as the magnetic field component value in one of the NV axes, although the coordinates have not been converted into the magnetic field intensity value in the spatial coordinate system (that is, the magnetic field intensity value after the vector sum of each component), the drive current can be adjusted according to the correspondence between the magnetic field component value and the magnetic field intensity value that has been calibrated in advance until the second measured value is the magnetic field component value corresponding to the magnetic field intensity value of zero. The zero value here includes zero and near-zero values that float around zero.

[0026] The control method can be achieved by setting the current change amount for each control, or by controlling the current change amount through a PID (proportional-integral-differential) algorithm, and finally obtaining the driving current value provided to the reverse magnetic field module by accumulating the current change amount.

[0027] After the offset magnetic field is reduced to zero, the current value in the current-carrying conductor can be calculated based on the driving current value provided to the reverse magnetic field module. The two are positively correlated, and this correlation can be determined based on a prior calibration experiment. The driving current value is determined by the current ultimately regulated by the feedback regulation module. The current calculation module 6 can be implemented by a lower computer or a host computer. For example, the feedback regulation module 5 uploads a signal corresponding to the driving current value to the host computer for calculation.

[0028] like Figure 2 As shown, the reverse magnetic field module 4 includes an open magnetic ring 41 and a coil 42 wound on the outer surface of the magnetic ring 41. The driving current is passed through the coil 42, and the current-carrying conductor 3 passes through the center of the magnetic ring 41. The auxiliary magnetic sensor and the solid-state spinning color center magnetometer both measure the magnetic field in the open air gap of the magnetic ring. The open magnetic ring 41 is a magnetic focusing ring that concentrates the magnetic field in the air gap. The coil 42 is wound on the magnetic ring 41 to form a spiral. The magnetic field generated is along the circumferential direction of the magnetic ring 41, which is opposite to the direction of the magnetic field generated by the current-carrying conductor 3, thereby canceling the magnetic field. For example, Figure 2 As shown, the auxiliary magnetic sensor 1 includes a magnetic sensitive module 101 and a signal acquisition module 102. The auxiliary magnetic sensor 1 in this embodiment adopts TMR. The magnetic sensitive module 101 for sensing the magnetic field is a TMR chip. The solid-state spinning color center magnetometer 2 for sensing the magnetic field is a probe containing a solid-state spinning color center, that is, the magnetic sensitive probe 21 in the figure. The magnetic sensitive module 101 and the magnetic sensitive probe 21 are placed in the open air gap of the magnetic ring 41 to measure the offset magnetic field.

[0029] The signal acquisition module 102 in this embodiment includes an instrumentation amplifier 1021, a first buffer 1022, a first analog-to-digital converter 1023, and a zeroing circuit 1024 connected to the instrumentation amplifier 1021. The instrumentation amplifier 1021 is connected to the signal output of the magnetic sensing module 101, and the first analog-to-digital converter 1023 is also connected to the input of the feedback regulation module 5. The instrumentation amplifier 1021 is used to amplify the first measurement value output by the magnetic sensing module 101. The processed signal is then buffered by the first buffer 1022 and converted into a digital signal by the first analog-to-digital converter 1023 and transmitted to the feedback regulation module 5. The first analog-to-digital converter 1023 uses a 24-bit high-precision converter type to ensure high-precision measurement values are input to the feedback regulation module 5, thereby reducing errors in subsequent current control. The zeroing circuit 1024 is used to adjust the output of the instrumentation amplifier 1021 in the static state to 0 mV, thereby reducing measurement deviation.

[0030] The feedback regulation module 5 includes a controller 51, a current signal processing module 52, and a driving module 53 connected in sequence; the controller 51 is also connected to the output end of the auxiliary magnetic sensor 1 and the solid-state spinning color center magnetometer 2, for receiving the first measurement value and the second measurement value. The controller 51 is also connected to the driving module 53 and the current calculation module 6, for controlling the driving module 53 to provide a driving current to the reverse magnetic field module 4, and to transmit a current regulation signal to the current signal processing module 52, and when the magnetic field strength value corresponding to the measured second measurement value is zero, obtain the driving current value provided to the reverse magnetic field module; after the current signal processing module 52 processes the current regulation signal, it transmits it to the driving module 53 to adjust the current it provides to the reverse magnetic field module 4.

[0031] The current signal processing module 52 includes a digital-to-analog converter 521, a signal amplifier 522, a filter 523, and a second buffer 524, which are connected in sequence. The digital-to-analog converter 521 is connected to the controller 51, and the second buffer 524 is connected to the driver module 53. The current regulation signal output by the controller 51 is converted to an analog signal by the digital-to-analog converter 521, then amplified by the signal amplifier 522, filtered by the filter 523 to prevent interference signals from causing current fluctuations in subsequent circuits, and then buffered by the second buffer 524 before being transmitted to the driver module 53 for current regulation. The digital-to-analog converter is a high-precision type to reduce regulation errors. The filter can be a fourth-order Butterworth filter, and the buffer can be an OPA189.

[0032] The driver module 53 further includes a driver power supply 531 and a MOS transistor 532. The driver power supply 531 is also connected to the controller 51 and, under the control of the controller 51, provides a DC voltage to the MOS transistor 532 and the reverse magnetic field module 4. The MOS transistor 532 and the reverse magnetic field module 4 form a series circuit. The second buffer 524 is connected to the MOS transistor 532 and transmits a current regulation signal to the MOS transistor 532 to regulate the current therein. Since the current in the reverse magnetic field module 4 is the same as the current in the MOS transistor, regulating the current in the MOS transistor is equivalent to regulating the current in the reverse magnetic field module 4. The coil 42 in the reverse magnetic field module 4 is connected in series with the MOS transistor 532.

[0033] The process of judging based on the measured value and regulating the driving current is completed by programming in the controller 51. Specifically, the controller 51 judges whether the first measured value is within a predetermined first threshold range based on the first measured value. The magnetic field strength value corresponding to the first threshold range is within the range of the solid-state spinning color center magnetometer. If not, the controller 51 transmits a start signal to the driving power supply 531 to start the driving power supply 531 to provide driving current to the reverse magnetic field module, and transmits a current control signal to the current signal processing module 52 to control the driving current in the MOS transistor 532, and performs real-time judgment and current control of the first measured value until the first measured value is within the predetermined threshold range. Then, the controller 51 performs real-time judgment and current control based on the second measured value until the second measured value is within the predetermined second threshold range, and the magnetic field strength value corresponding to the second threshold range is zero. If it is, the controller 51 transmits a start signal to the driving power supply 531 to start the driving power supply 531 to provide driving current to the reverse magnetic field module 4, and transmits a current control signal to the current signal processing module 52 to control the driving current in the MOS transistor 532, and performs real-time judgment and current control of the second measured value until the second measured value is within the predetermined second threshold range.

[0034] like Figure 3 As shown, the driving power supply 531 in this embodiment includes a power supply circuit 10, which includes a DC output power supply 11, an on-off switch 12, a voltage conversion module 13, and an anti-leakage module 14 connected in sequence; the controller 51 is also connected to the on-off switch 12 and the voltage conversion module 13, and starts the voltage output of this power supply circuit by controlling the on-off switch 12, and controls the voltage output of this power supply circuit by regulating the voltage conversion module 13.

[0035] The DC output power supply 11 can be an AC-DC power supply, and the output voltage can be set as needed, for example, converting 220V AC to 24V, 20V, or 16V. Alternatively, a combination of an AC-DC power supply and a DC-DC power supply can be used, for example, first converting 220V AC to 24V DC, and then converting the 24V DC to 20V or 16V. Exemplary DC output power supplies all use switching power supplies, but other forms of DC output power supplies can also be used, and existing power supply products or circuit boards can be used.

[0036] The circuit diagram of the on-off switch 12 is shown as an example. Figure 4 As shown, it includes a first PMOS switch circuit 121 , a discharge circuit 122 , and an anti-backflow circuit 123 connected in sequence, and the controller 51 is connected to the first PMOS switch circuit 121 .

[0037] like Figure 4As shown, the first PMOS switch circuit 121 includes a PMOS switch Q1 and a transistor Q2. The source of the PMOS switch Q1 is connected to the output terminal of the DC output power supply 11. The voltage of the DC output power supply 11 is exemplarily represented in the figure as 16V. The gate is connected to the collector of the transistor Q2. The drain, as the output terminal, is connected to the input terminal of the bleeder circuit 122. A control signal N1 from the controller 51 (in this embodiment, the controller exemplarily employs a single-chip microcomputer) is connected to the base of the transistor Q2, for example, at a high or low level. This signal controls the on / off state of the transistor Q2, thereby controlling the on / off state of the PMOS switch Q1. The emitter of the transistor Q2 is grounded. To achieve better current limiting and circuit protection, a resistor R3 is provided. Its first end is used to input the control signal N1, and its second end is connected to the base of the transistor Q2 to limit the current flowing into the base of the transistor Q2. A resistor R4 is also provided. One end is connected to the first end of the resistor R3 and the other end is grounded to stabilize the base potential. A resistor R2 is connected in series between the collector of transistor Q2 and the gate of PMOS switch Q1. A capacitor C1 and a resistor R1 are also provided. Capacitor C1 has a first end connected to the source of PMOS switch Q1 and a second end connected to the gate of PMOS switch Q1. Resistor R1 has one end connected to the source of PMOS switch Q1 and the other end connected to the collector of transistor Q2. Charging C1 through resistors R1 and R2 delays the turn-on of PMOS switch Q1, reducing inrush current and protecting the circuit. After PMOS switch Q1 turns on, C1 stores a certain amount of electrical energy, acting as a buffer and stabilizing voltage. A Schottky diode D1 is also connected between the drain of PMOS switch Q1 and the input of bleeder circuit 122, with its anode connected to the drain of PMOS switch Q1 to protect against reverse voltage.

[0038] Discharge circuit 122 includes a TVS diode D2, two capacitors C2 and C3, and a transistor Q3. The cathode of TVS diode D2, one end of the two capacitors, and the collector of transistor Q3 are all connected to the line connecting the output of first PMOS switch circuit 121 (shown as the cathode of Schottky diode D1) and the input of backflow prevention circuit 123. The other ends of TVS diode D2 and the two capacitors C2 and C3 are grounded. The base of transistor Q3 is connected to control signal DIS_EN1, which controls the on / off state of transistor Q3, and the emitter is grounded. TVS diode D2 provides freewheeling, and the two capacitors C2 and C3, one large and one small, store energy. When the PMOS switch circuit is off, control signal DIS_EN1 controls transistor Q3 to conduct, dissipating energy to protect the circuit. Before the first PMOS switch circuit is on, control signal DIS_EN1 controls transistor Q3 to turn off, ensuring normal conduction of the first PMOS switch circuit.

[0039] A resistor R5 is also provided, one end of which is connected to the connecting line between the output end of the first PMOS switch circuit 121 and the input end of the backflow prevention circuit 123, and the other end is connected to the collector of the transistor Q3, thereby providing current limiting protection. A resistor R6 is also provided, a first end of which is connected to the base of the transistor Q3, and a second end of which is used to input the control signal DIS_EN1 for limiting the current flowing into the base of the transistor Q3. A resistor R7 is also provided, one end of which is connected to the second end of the resistor R6 and the other end is grounded, thereby stabilizing the base potential of the transistor Q3.

[0040] The backflow prevention circuit 123 includes a Schottky diode D3, whose anode is connected to the output of the discharge circuit 122 and whose cathode is connected to the input of the voltage conversion module 13 (shown as 16VO in the figure), and is used to cut off the reverse voltage and protect the circuit; and also includes a Schottky diode D4, whose cathode is connected to the input of the voltage conversion module 13 and whose anode is grounded, and has a voltage stabilizing effect.

[0041] like Figure 5 As shown, the voltage conversion module 13 includes a low-voltage difference regulator 131 and a digital potentiometer 132 connected to each other. The low-voltage difference regulator 131 is connected to the output end of the on-off switch 12 and the input end of the anti-leakage module 14. The digital potentiometer 132 is connected to the controller 51. The controller 51 adjusts the voltage output by the low-voltage difference regulator 131 by adjusting the resistance of the digital potentiometer 132.

[0042] The circuit diagram of the voltage conversion module 13 is as follows: Figure 5 As shown, the VIN pin of the low-voltage difference regulator chip is connected to the output end of the on-off switch 12 (shown as 16VO in the figure), the ADJ pin is connected to the W pin of the digital potentiometer chip, and the VOUT pin is connected to the input end of the leakage protection module 14; and a capacitor C4 is provided, one end of which is connected to the output end of the on-off switch 12 (shown as 16VO in the figure) and the other end is grounded to achieve filtering and voltage stabilization; a resistor R8 is connected between the ADJ pin and the VOUT pin of the low-voltage difference regulator chip, a resistor R9 is connected in series between the ADJ pin and the W pin of the digital potentiometer chip, and the ADJ pin is also connected to a resistor R10 connected in series with a resistor R20 and a resistor R30 connected in series with a resistor R40. Resistor R11, the resistance value of resistor R10 is 0R, resistor R11 is a variable resistor, its variable end is connected to resistor R10, and the other end is grounded. The resistance value of resistor R11 in the circuit can be manually adjusted, which is suitable for debugging. During debugging, disconnect R9 and only change its voltage division by adjusting R11, thereby adjusting the voltage output of the low-voltage difference regulator 131. During normal detection, disconnect R10 and turn on R9, and adjust the voltage output of the low-voltage difference regulator 131 by adjusting the resistance of the digital potentiometer; when R9 is turned on, turn on R10 as well, and use R11 as an auxiliary adjustment during detection, so that the adjustment method is diversified. The control signal sent by the controller 51 is composed of CLK, SDI, The pins are connected to control the resistance of the chip, and the divided voltages change accordingly, thereby adjusting the voltage output by the low-dropout regulator 131. Fine adjustment steps as small as 200mV can be achieved, which helps to improve the accuracy of the adjustment.

[0043] like Figure 5 As shown, the leakage prevention module 14 includes a Schottky diode D5, the positive electrode of which is connected to the output end of the low voltage difference regulator 131, and the negative electrode serves as the voltage output end, for example, the output 12V as shown in the figure, and also includes a capacitor C6, one end of which is also connected to this voltage output end and the other end is grounded to achieve filtering and voltage stabilization.

[0044] The circuit diagram of the driver module is as follows Figure 6 As shown, it also includes a coil interface J1 for connecting to the coil 42. The VBUS_OUT terminal in the figure is connected to the output voltage of the driving power supply 531 and is connected to the No. 2 pin of the coil interface J1 through a Schottky diode D6. The Schottky diode D6 is used to prevent reverse voltage. The No. 1 pin of the coil interface J1 is connected to the source of the MOS tube 532. The MOS tube here is exemplarily an NMOS tube. The gate of the MOS tube 532 is connected to the output terminal of the second buffer 524 (for example, the OUT pin of the OPA189 buffer chip) through a resistor R15 for connecting to the current regulation signal and changing the resistance of the MOS tube by controlling the gate voltage, thereby realizing the regulation of the current in the MOS tube; the drain is connected to the feedback access terminal of the second buffer 524 (for example, the -IN pin of the OPA189 buffer chip). Two parallel resistor circuits are also provided ( Figure 6 (The resistor circuits R16 and R17 are connected in series, and R18 and R19 are connected in series. R19 is NC and not soldered to facilitate debugging and sampling.) One end of each circuit is connected to the connection line between the drain and the feedback input terminal of the second buffer 524, and the other end is connected to ground. This circuit is used to provide current feedback from the drain to the second buffer 524 to maintain current stability. A Schottky diode D7 is also provided, with its cathode connected to pin 2 of the coil interface J1 and its anode connected to pin 1 of the coil interface J1. This diode is used to release residual energy after the coil 42 is disconnected. A TVS diode D8 is also provided, with its cathode connected to the source of the MOS transistor 532 and its anode grounded. A capacitor C7 is provided in parallel with the TVS diode D8 to prevent overvoltage and protect the MOS transistor 532.

[0045] like Figure 6As shown, a second PMOS switch circuit 533 is also provided, connected between the voltage output terminal of the driving power supply 531 and the voltage input terminal of the coil 42 (VBUS_IN terminal and VBUS_OUT terminal are connected in the figure), and is connected to the controller 51. Its circuit structure is the same as the circuit structure of the first PMOS switch circuit 121 and will not be repeated here. The driving power supply 531 is connected via the power interface J2; the control signal MOS-POWER-EN3 from the controller 51 is connected to the transistor Q5. The drain of the PMOS switch Q4, i.e., the VBUS_IN terminal shown in the figure, is connected to the voltage input terminal VBUS_OUT of the coil interface J1. By controlling the on-off of the transistor Q5, the on-off of the PMOS switch Q4 is controlled, thereby controlling the on-off of the output voltage of the driving power supply 531. This is used to disconnect the voltage when a fault occurs in the coil 42, such as a current overload, thereby protecting the circuit.

[0046] The controller 51 can be a single chip microcomputer, DSP, FPGA, ARM, etc.

[0047] like Figure 2 As shown, a schematic structural diagram of a solid-state spin color center magnetometer 2 is provided as an example, comprising a magnetically sensitive probe 21, an optical detection unit 22, a microwave unit 23, and a control and calculation unit 24. The magnetically sensitive probe 21 contains a solid-state spin color center for sensing magnetic fields and is placed in the open air gap of the magnetic ring 41. The optical detection unit 22 is used to irradiate excitation light onto the magnetically sensitive probe 21 and detect the fluorescence generated by the magnetically sensitive probe 21. This excitation light is used to excite the solid-state spin color center to generate fluorescence. The microwave unit 23 is used to radiate microwaves onto the magnetically sensitive probe 21. The control and calculation unit 24 is used to control the frequency of the microwaves radiated by the microwave unit 23 onto the magnetically sensitive probe 21, collect the fluorescence electrical signal from the optical detection unit 22, obtain the resonant frequency, and calculate the magnetic field intensity value or the magnetic field component value along one of the color center axes based on the resonant frequency. This magnetic field intensity value or the magnetic field component value along one of the color center axes is output as a second measurement value to the feedback adjustment module 5.

[0048] The magnetic measurement principle of the solid-state spin color center magnetometer is to use the Zeeman splitting effect of the color center ground state energy level caused by the external magnetic field, detect the frequency shift of the resonance point of the ODMR (optical detection magnetic resonance) spectrum, and then convert the frequency shift into magnetic field intensity, thereby achieving the purpose of detecting the external magnetic field B.

[0049] Solid-state spin color centers are one of the following: diamond nitrogen-vacancy color centers, diamond germanium-vacancy color centers, diamond silicon-vacancy color centers, silicon carbide silicon-carbon divacancy color centers, silicon carbide silicon-vacancy color centers, and hexagonal boron nitride boron-vacancy color centers. All of these utilize photoluminescence to achieve quantum precision measurement. The probe structure can be micron or nanoparticles, or micron or centimeter-scale bulk structures. For example, the diamond nitrogen-vacancy color center probe can be a diamond particle or block containing an NV color center.

[0050] For example, Figure 7 As shown, the optical detection unit 22 includes an illumination device and a fluorescence detection device. The illumination device includes an excitation light source 221, which can be a laser or LED light source. The illumination device may also include components for processing the light generated by the light source, such as components for filtering and collimation. In this embodiment, the excitation light source 221 is a laser source. The fluorescence detection device includes a filter 222 and a photodetector 223, which converts the received fluorescence into an electrical signal and transmits it to the control and calculation unit 24.

[0051] In this embodiment, fluorescence is collected from the excitation light irradiation side. To achieve the separation and guidance of excitation light and fluorescence, the optical detection unit 22 further includes at least one optical element for guiding the excitation light generated by the excitation light source to the probe and guiding the fluorescence generated by the probe to the fluorescence detection device. Figure 7 As shown in FIG, a dichroic filter 224 is used to reflect the excitation light toward the magnetically sensitive probe 21. The fluorescence generated by the magnetically sensitive probe 21 is transmitted through the dichroic filter 224, filtered out by the filter 222, and then detected by the photodetector 223. The dichroic filter 224 can also be replaced with other optical elements, such as an optical circulator, or a combination of multiple optical elements, which will not be described in detail here.

[0052] The optical detection unit may also adopt other structural forms, which will not be described here.

[0053] In this embodiment, optical fiber is used to transmit laser light and fluorescence, but spatial light transmission may also be used.

[0054] For different solid-state spin color centers, the wavelength of the excitation light may be different. For example, for diamond nitrogen vacancy color centers and hexagonal boron nitride boron vacancy color centers, 532nm green excitation light is generally used; silicon carbide divacancy color centers use 900-940nm excitation light. Other color centers can be excited with corresponding excitation light.

[0055] The microwave unit 23 is exemplified as Figure 7The microwave source 231, microwave switch 232, microwave amplifier 233, microwave isolator 234, and microwave antenna 235 are shown. The microwave generated by the microwave source 231 is transmitted to the microwave amplifier 233 through the microwave switch 232 for amplification, and then transmitted to the microwave antenna 235 through the microwave isolator 234. The microwave antenna 235 radiates the microwave to the magnetic sensitive probe 21. The microwave antenna 235 is close to the magnetic sensitive probe 21, so that the magnetic sensitive probe 21 is within the microwave near-field radiation range. Figure 7 As shown, a spiral antenna is selected, and the magnetic sensitive probe 21 is selected from diamond containing NV color centers. The spiral coil is set on the outside of the diamond to radiate microwaves to the diamond.

[0056] The control and calculation unit 24 includes a control module 241 and a magnetic field calculation module 242. In this embodiment, ODMR measurement is performed using a microwave frequency sweep method. The control module 241 is connected to the microwave source 231 and is used to control the microwave source 231 to perform microwave frequency sweeps. The control module 241 transmits frequency-cutting pulses to the microwave source 231 to achieve frequency sweeps. The frequency-cutting pulses are TTL-level signals. The magnetic field calculation module 242 is connected to the photodetector 223 and is used to collect the fluorescent electrical signal and, based on the ODMR spectrum of the fluorescent electrical signal varying with frequency, obtain the resonant frequency. Based on the resonant frequency, the magnetic field intensity value or the magnetic field component value along one of the color center axes is calculated and transmitted as the second measured value to the feedback adjustment module 5. During ODMR measurement, the angle between the color center axis and the magnetic field direction can be adjusted so that only one pair of resonant frequency points appear on the ODMR spectrum after the frequency sweep, facilitating the search for the resonant frequency and the calculation of the magnetic field components.

[0057] For the calculation of the magnetic field, taking the diamond nitrogen vacancy color center as an example, the resonance frequency is determined according to the ODMR spectrum. 、 , and according to To calculate the magnetic field component in each axis ,in is the gyromagnetic ratio, and the magnitude and / or direction of the spatial magnetic field is obtained from the conversion relationship between the axial direction and the spatial coordinates.

[0058] Regarding the magnetic field generated by the current-carrying conductor, since the magnetic field generated by the current-carrying conductor is along its circumferential direction, the magnetic sensitive probe 21 is placed in the open air gap of the magnetic ring 41, that is, at a point on the circumference. Alternatively, one axial direction of the color center can be parallel to the magnetic field direction at this point. In this way, the magnetic field strength calculated from a pair of resonant frequencies along the axial direction of the color center is the magnetic field strength along its circumferential direction.

[0059] In the ODMR measurement in this embodiment, the resonant frequency can also be obtained by frequency tracking. The control module 241 and the magnetic field calculation module 242 at this time are different from the aforementioned ones. The control module 241 is used to provide a frequency modulation signal to the microwave module 23, collect the fluorescent electrical signal, and demodulate the fluorescent electrical signal, and use the PID algorithm to control the microwave frequency applied by the microwave module 23 to obtain the resonant frequency corresponding to the measured magnetic field, and transmit the obtained resonant frequency to the magnetic field calculation module 242. The magnetic field calculation module 242 calculates the magnetic field intensity value or the magnetic field component value on one of the color center axes according to the resonant frequency, and transmits this magnetic field intensity value or the magnetic field component value on one of the color center axes as the second measurement value to the feedback adjustment module 5. Control module 241 specifically provides a frequency-modulated signal to microwave source 231. Microwave source 231 modulates its frequency according to the frequency-modulated signal, collects the fluorescent electrical signal transmitted by photodetector 223, and demodulates the fluorescent electrical signal to obtain demodulated data. Using a PID algorithm, the frequency of the modulated microwaves radiated by microwave module 23 is adjusted until the demodulated data reaches a target value. At this point, the microwave frequency corresponding to this demodulated data is the resonant frequency corresponding to the current magnetic field. Since the resonant frequency is located at the zero crossing point in the demodulation curve drawn from the demodulated data, the target value is set to zero or near zero in PID frequency tracking.

[0060] Example 2: Figure 8 As shown, based on the first embodiment, the driving power supply 531 of this embodiment includes multiple power supply circuits 10, and the controller 51 is connected to the on-off switch 12 and the voltage conversion module 13 in each power supply circuit. According to the required voltage, the on-off switch 12 is controlled to switch one of the power supply circuits 10 as the output end of the power supply, and the voltage output by this power supply circuit is controlled by regulating the voltage conversion module 13.

[0061] In this embodiment, multiple power supply circuits are provided, and a controller is used to control the on / off switches in the power supply circuits and regulate the voltage of the voltage conversion module according to the required voltage to achieve the desired voltage output. The number of power supply circuits and the output voltage can be set as needed, enabling a wide range of voltage outputs with multiple values. The corresponding power supply circuit can be switched according to the required voltage. This required voltage can be calculated based on the required current in the circuit, the minimum power of the MOS transistor 532, the resistance of the coil 42, and the resistance of other components in the circuit. Thus, while meeting the coil current requirements, the power of the MOS transistor is controlled, solving the heating problem, reducing the impact of temperature drift, and improving the accuracy of the current supply. At the same time, the automated control and convenient operation reduce the requirements for heat dissipation components and the circuit size, which facilitates the miniaturization of the current sensor.

[0062] The DC output power supply 11 in each power supply circuit can adopt an AC-DC power supply, and the output voltage can be set as needed. Figure 8 As shown, the DC output power supply in one of the power supply circuits is an AC-DC power supply, and the power supply in each of the remaining power supply circuits is a DC-DC power supply (DC-DC) connected to the AC-DC power supply. Figure 8 Three power supply circuits are given as examples. The first power supply circuit uses an AC-to-DC power supply to convert the 220V AC voltage into a 24V DC voltage. The second and third power supply circuits use a DC-to-DC power supply connected to this AC-to-DC power supply to convert the 24V DC voltage into 20V and 16V DC voltages respectively. This method can further simplify the circuit, save costs, and reduce the size of the circuit.

[0063] like Figure 8 A resistance detection module 8 is also provided, connected to the controller 51, for detecting the resistance of the coil 42 and transmitting a resistance detection signal to the controller 51. For coils 42 with different numbers of turns, the resistance detection module 8 can be used to detect the resistance value, and the controller 51 can obtain the resistance value. When the coil is used, the voltage division of the coil is calculated based on the resistance detection signal and the current regulation signal. The voltage division is calculated based on the MOS transistor in the circuit at an appropriate power. This appropriate power is the power to avoid heating. The voltage division of other parts is then calculated or tested based on the resistance of other known components in the circuit. Finally, the total voltage required to be provided is calculated as the required voltage. The calculation method is executed by the controller 51. The resistance detection module 8 can be a commonly used resistance detection instrument or circuit, such as a DC resistance tester, a digital multimeter, a bridge circuit, a volt-ampere measurement circuit, etc., by transmitting the measured resistance detection signal to the controller 51.

[0064] It also includes a current detection module 7, which is connected to the reverse magnetic field module 4 and is used to detect the current flowing in the reverse magnetic field module 4 to form a current measurement signal. It is also connected to the feedback regulation module 5 and is used to transmit the current measurement signal to the feedback regulation module 5 to obtain a current value. The feedback regulation module also compares this current value with the driving current value provided to the reverse magnetic field module to determine whether the operation of the feedback regulation module is normal. Figure 2 As shown, the current detection module 7 includes a detection resistor 71, a current detection amplifier 72, and a second analog-to-digital converter 73. The current detection amplifier 72 detects the voltage drop across the detection resistor 71 and is connected to the second analog-to-digital converter 73. The second analog-to-digital converter 73 is connected to the controller 51. The resistance of the detection resistor 71 is known and is connected in series with the coil 42. For example, Figure 9 As shown in the circuit diagram, the two ends of the detection resistor 71 are connected to Figure 6As shown, between the VBUS_IN and VBUS_OUT terminals, a current sensing amplifier 72 is connected to both ends of a sensing resistor 71. It detects the voltage drop across the two ends to form a current measurement signal, which is then converted to a digital signal by a second analog-to-digital converter 73 and transmitted to the controller 51 for current calculation. The controller 51 can compare the current calculated from the current measurement signal with the acquired drive current to determine whether the feedback regulation module is operating normally. It can also be used to determine whether the current in the coil 42 is overloaded or whether a fault exists. When setting up a series sensing resistor, the voltage divider of the sensing resistor needs to be taken into account when calculating the required voltage for switching the power supply circuit.

[0065] The circuit diagram of the current detection module 7 is as follows: Figure 9 As shown, the IN+ and IN- pins of the current detection amplifier chip are connected in series with resistors (R24 and R25) and then connected to the two ends of the detection resistor 71 for detecting the voltage divider and calculating the current. A capacitor C9 is connected between the IN+ and IN- pins for filtering and voltage stabilization, and resistors R24 and R25 are used for current limiting protection. Two TVS diodes D9 and D10 are also provided, with their cathodes connected to one end of the detection resistor 71 and their anodes grounded for voltage stabilization. The VS pin of the current detection amplifier chip is connected to the supply voltage. Two parallel capacitors C10 and C11 are connected to the connection line between the VS pin of the current detection amplifier chip and the supply voltage, with their other ends grounded. The two capacitors have different capacitances, one large and one small, to filter noise and provide a stable voltage for the chip. To facilitate debugging and selective design, a 0R resistor R26 is also provided, with a first end connected to the OUT pin of the current detection amplifier chip and a second end as a voltage output end connected to the controller 51. A capacitor C12 is also provided, with one end connected to the second end of the resistor R26 and the other end grounded. On the one hand, R26 is convenient for debugging, and on the other hand, it forms an RC circuit with C12 to filter unwanted noise components when they exist in the output voltage, thereby outputting a stable voltage.

[0066] like Figure 8 As shown, an alarm 91 and an indicator light 92 are also provided. The alarm 91 is used to alarm the overload condition of the coil 42 for subsequent processing; the indicator light 92 is used to indicate the working status. Indicators showing multiple working statuses can be provided, such as normal operation, abnormal operation, abnormal parameters, etc., depending on needs.

[0067] Compared to the first embodiment, the controller of this embodiment also has the function of switching the voltage output of the driving power supply in a timely manner according to the regulated current. While issuing a current regulation signal, it also transmits a control signal to the on / off switch of the power supply circuit to switch on and off, and transmits a regulation signal to the digital potentiometer to adjust the voltage output, according to the required voltage. Thus, while achieving current regulation in the coil, it also matches the appropriate driving voltage to the coil, thereby controlling the power of the MOS tube, solving the problem of heat generation, and improving the accuracy of the current supply.

[0068] Embodiment 3: This embodiment provides a current detection method based on zero magnetic flux, including: Providing a driving current to a reverse magnetic field module to generate a second magnetic field in a direction opposite to the first magnetic field, wherein the first magnetic field is generated by the current-carrying conductor to be measured; The auxiliary magnetic sensor and the solid-state spinning color center magnetometer are used to detect the magnetic field formed by superposition of the first magnetic field and the second magnetic field, and a first measurement value and a second measurement value are obtained respectively; the measurement range of the auxiliary magnetic sensor is greater than the measurement range of the solid-state spinning color center magnetometer; Adjusting the provided driving current according to the first measurement value until the magnetic field strength value corresponding to the measured first measurement value is within the range of the solid-state spinning color center magnetometer, and then adjusting the provided driving current according to the second measurement value until the magnetic field strength value corresponding to the measured second measurement value is zero; The current value in the current-carrying conductor to be measured is calculated according to the driving current value provided to the reverse magnetic field module.

[0069] In this embodiment, in the initial state, the drive current provided to the reverse magnetic field module can be zero or any other arbitrary value. Control of the drive current based on the magnetic measurement value can be achieved by setting the current change for each adjustment, or by controlling the current change using a PID (Proportional-Integral-Derivative) algorithm. The PID control method involves adjusting the change in the drive current and comparing the resulting magnetic measurement value with a target value until the measured electrical signal equals the target value, where the target value is the magnetic measurement value corresponding to the desired magnetic field strength. Control using this dynamic feedback method requires real-time magnetic measurement values for comparative feedback. In this method, real-time measurements from the auxiliary magnetic sensor and the solid-state spinning color center magnetometer are maintained, and corresponding magnetic measurement values are collected based on feedback needs.

[0070] When performing regulation, the first measurement value is first judged. If the first measurement value is within a preset first threshold range, the provided drive current is regulated according to the second measurement value until the measured second measurement value is within the second threshold range; wherein the magnetic field intensity value corresponding to the first threshold range is within the measuring range of the solid-state spinning color center magnetometer, and the magnetic field intensity value corresponding to the second threshold range is zero; if the first measurement value is not within the preset first threshold range, the provided drive current is regulated according to the first measurement value until the measured first measurement value is within the first threshold range, and then the provided drive current is regulated according to the second measurement value until the measured second measurement value is within the second threshold range.

[0071] The auxiliary magnetic sensor in this embodiment is a sensor with a large range. Taking advantage of its large range, the current in the reverse magnetic field module is regulated based on the first measurement value so that the offset magnetic field is within the range of the solid-state spinning color-center magnetometer. Next, taking advantage of the high sensitivity and high precision of the solid-state spinning color-center magnetometer, the current in the reverse magnetic field module is regulated based on the second measurement value until the offset magnetic field is zero. At this point, the current in the current-carrying conductor is calculated based on the last current passed through the reverse magnetic field module, thereby achieving high-sensitivity and high-precision measurement of a large range of currents.

[0072] The method in this embodiment can be implemented by the quantum current sensor in the first or second embodiment. For the composition and function of each module, please refer to the relevant description in the first or second embodiment, which will not be repeated here.

[0073] Table 1 shows the test data obtained by the current detection method according to this embodiment. Only when the theoretical value of the current in the current-carrying conductor is 500A is the accuracy 0.08%. The accuracy of other larger current levels is below 0.05%, indicating that this embodiment can perform high-precision measurements under a wide range of magnetic fields.

[0074] Table 1

[0075] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A quantum current sensor based on zero magnetic flux, characterized in that: The quantum current sensor comprises: A reverse magnetic field module, configured to generate a second magnetic field in a direction opposite to the first magnetic field after a driving current is applied, wherein the first magnetic field is generated by the current-carrying conductor to be measured; The auxiliary magnetic sensor and the solid-state spinning color center magnetometer are both located in the superimposed magnetic field of the first magnetic field and the second magnetic field, and are used to measure the superimposed magnetic field and output a first measurement value and a second measurement value respectively; the measurement range of the auxiliary magnetic sensor is greater than the measurement range of the solid-state spinning color center magnetometer; a feedback regulation module, configured to provide a driving current to the reverse magnetic field module, and regulate the provided driving current according to the first measurement value until the magnetic field intensity value corresponding to the measured first measurement value is within the range of the solid-state spinning color center magnetometer; and then regulate the provided driving current according to the second measurement value until the magnetic field intensity value corresponding to the measured second measurement value is zero, and finally obtain the driving current value provided to the reverse magnetic field module; The current calculation module is used to calculate the current value in the current-carrying conductor according to the driving current value.

2. The zero-flux quantum current sensor according to claim 1, characterized in that: The reverse magnetic field module includes an open magnetic ring and a coil wound on the outer surface of the magnetic ring. A driving current is passed through the coil, and a current-carrying conductor passes through the center of the magnetic ring. Both the auxiliary magnetic sensor and the solid-state spinning color center magnetometer measure the magnetic field in the open air gap of the magnetic ring.

3. The zero-flux quantum current sensor according to claim 1, characterized in that: The feedback regulation module includes a controller, a current signal processing module, and a driving module connected in sequence; the controller is also connected to the auxiliary magnetic sensor and the output end of the solid-state spinning color center magnetometer, and is used to receive the first measurement value and the second measurement value. The controller is also connected to the driving module and the current calculation module, and is used to control the driving module to provide a driving current to the reverse magnetic field module, and transmit a current regulation signal to the current signal processing module, and obtain the driving current value provided to the reverse magnetic field module when the magnetic field strength value corresponding to the measured second measurement value is zero; after processing the current regulation signal, the current signal processing module transmits it to the driving module to adjust the current it provides to the reverse magnetic field module.

4. The zero-flux quantum current sensor according to claim 3, characterized in that: The driving module includes a driving power supply and a MOS transistor. The driving power supply is connected to a controller and provides a DC voltage to the MOS transistor and the reverse magnetic field module under the control of the controller. The MOS transistor and the reverse magnetic field module form a series circuit. The current signal processing module is also connected to the MOS transistor and transmits a current regulation signal to the MOS transistor to regulate the current therein.

5. The zero-flux quantum current sensor according to claim 4, characterized in that: The driving power supply includes one or more power supply circuits, each of which includes a DC output power supply, an on-off switch, a voltage conversion module, and an anti-leakage module connected in sequence; the controller is also connected to the on-off switch and the voltage conversion module in each power supply circuit, and starts the voltage output of the corresponding power supply circuit by controlling the on-off switch, and controls the voltage output of this power supply circuit by regulating the voltage conversion module; when multiple power supply circuits are included, each power supply circuit corresponds to a different output voltage.

6. The zero-flux quantum current sensor according to claim 1, characterized in that: It also includes a current detection module, which is connected to the reverse magnetic field module and is used to detect the current flowing into the reverse magnetic field module to form a current measurement signal. It is also connected to the feedback regulation module and is used to transmit the current measurement signal to the feedback regulation module to obtain a current value. The feedback regulation module also compares this current value with the driving current value provided to the reverse magnetic field module to determine whether the operation of the feedback regulation module is normal.

7. The zero-flux quantum current sensor according to any one of claim 1, characterized in that: The solid-state spin color center magnetometer includes a magnetically sensitive probe, an optical detection unit, a microwave unit, and a control and calculation unit. The magnetically sensitive probe contains a solid-state spin color center for sensing magnetic fields. The optical detection unit is used to irradiate excitation light onto the magnetically sensitive probe and detect fluorescence generated by the magnetically sensitive probe, wherein the excitation light is used to excite the solid-state spin color center to generate fluorescence. The microwave unit is used to radiate microwaves onto the magnetically sensitive probe. The control and calculation unit is used to control the frequency of microwaves radiated by the microwave unit to the magnetically sensitive probe, collect the fluorescent electrical signal from the optical detection unit, obtain the resonant frequency, and calculate the magnetic field intensity value or the magnetic field component value along one of the color center axes based on the resonant frequency. This magnetic field intensity value or the magnetic field component value along one of the color center axes is output as a second measurement value to the feedback adjustment module.

8. The zero-flux quantum current sensor according to any one of claim 1, characterized in that: The auxiliary magnetic sensor is a Hall sensor or a magnetoresistive sensor.

9. The zero-flux quantum current sensor according to any one of claims 1 to 8, characterized in that: The solid-state spin color center is one of a diamond nitrogen vacancy color center, a diamond germanium vacancy color center, a diamond silicon vacancy color center, a silicon carbide silicon-carbon double vacancy color center, a silicon carbide silicon vacancy color center, and a hexagonal boron nitride boron vacancy color center.

10. A current detection method based on zero magnetic flux, characterized in that: The method comprises: Providing a driving current to a reverse magnetic field module to generate a second magnetic field in a direction opposite to the first magnetic field, wherein the first magnetic field is generated by the current-carrying conductor to be measured; The auxiliary magnetic sensor and the solid-state spinning color center magnetometer are used to detect the magnetic field formed by superposition of the first magnetic field and the second magnetic field, and a first measurement value and a second measurement value are obtained respectively; the measurement range of the auxiliary magnetic sensor is greater than the measurement range of the solid-state spinning color center magnetometer; Adjusting the provided driving current according to the first measurement value until the magnetic field strength value corresponding to the measured first measurement value is within the range of the solid-state spinning color center magnetometer, and then adjusting the provided driving current according to the second measurement value until the magnetic field strength value corresponding to the measured second measurement value is zero; The current value in the current-carrying conductor to be measured is calculated according to the driving current value provided to the reverse magnetic field module.

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