CN116679112B - Single-magnetic-core four-winding magnetic modulation type current sensor and oscillation elimination method thereof - Google Patents

Single-magnetic-core four-winding magnetic modulation type current sensor and oscillation elimination method thereof

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Publication number
CN116679112B
CN116679112B CN202310670166.3A CN202310670166A CN116679112B CN 116679112 B CN116679112 B CN 116679112B CN 202310670166 A CN202310670166 A CN 202310670166A CN 116679112 B CN116679112 B CN 116679112B
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winding
circuit
oscillation
current
excitation
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CN116679112A (en
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陈威
郭镇镇
舒亮
吴自然
林义刚
林振权
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Yueqing Institute Of Industry Wenzhou University
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Yueqing Institute Of Industry Wenzhou University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/0092—Measuring current only
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
    • H03K3/027—Generators characterised by the type of circuit or by the means used for producing pulses by the use of logic circuits, with internal or external positive feedback

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  • General Physics & Mathematics (AREA)
  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
  • Measurement Of Current Or Voltage (AREA)

Abstract

A single-magnetic core four-winding magnetic modulation type current sensor and a method for eliminating oscillation thereof relate to the technical field of sensing. The invention relates to a single-magnetic-core four-winding magnetic modulation type current sensor with a special structure, which comprises a single-magnetic-core four-winding structure and a peripheral circuit, wherein a magnetic core C, an exciting winding W ex, a primary side winding W p, a feedback winding W s and an induction winding W i are matched with the peripheral circuit to form a whole together. The invention solves the problem of voltage oscillation on the sampling resistor in the feedback loop when the self-oscillation fluxgate method is applied to a single magnetic core closed loop feedback structure.

Description

Single-magnetic-core four-winding magnetic modulation type current sensor and oscillation elimination method thereof
Technical Field
The invention relates to the technical field of sensing, in particular to a single-magnetic-core four-winding magnetic modulation type current sensor and a method for eliminating oscillation thereof.
Background
In recent years, with the development of technology, the power electronic technology is mature, and corresponding power electronic power devices are also developed sequentially, so that the advantages of the direct current power supply and distribution system are developed gradually. Meanwhile, new energy power generation technology is mature, the duty ratio of photovoltaic power generation is increased gradually, and accordingly the demand for direct current plastic shell circuit breakers is increased.
The current intelligent circuit breaker not only has the function of a protection circuit, but also can meter the flowing current. The direct current sensor can detect and measure current, and can be arranged in the direct current molded case circuit breaker after modularization and miniaturization, so that the circuit breaker is intelligent. The volume of the current sensor which can be integrated in the intelligent direct current molded case circuit breaker is smaller than the internal space of the molded case circuit breaker, and the measuring range is higher than 1.2 times of rated current of the intelligent direct current molded case circuit breaker.
Current methods for measuring dc current include shunt method, hall effect method, giant magneto resistance method, magneto-optical effect method, and magnetic modulation method. The magnetic modulation method is more suitable for direct current metering in the direct current molded case circuit breaker by integrating factors such as precision, cost, volume, applicable scene and the like. The self-excited oscillation fluxgate method in the magnetic modulation technology has been widely used because of the characteristics of no need of an extra square wave excitation source, simple structure, low cost and the like. However, when the self-excited oscillation fluxgate method is applied to a closed-loop feedback system with a single magnetic core, oscillation waves generated by an excitation winding of the self-excited oscillation fluxgate method can exist in the feedback winding due to the effect of a transformer, so that sampling signals on a feedback resistor are affected.
Therefore, how to solve the problem of voltage oscillation on the sampling resistor in the feedback loop when the self-oscillation fluxgate method is applied to a single-magnetic-core closed-loop feedback structure is a current urgent problem to be solved.
Disclosure of Invention
The invention provides a novel magnetic modulation type current sensor with a single magnetic core and four winding closed loop structure and a method for eliminating oscillation, and aims to provide a scheme which can be applied to internal current measurement of a direct current molded case circuit breaker.
The technical scheme adopted by the invention is as follows:
a single-core four-winding magnetic modulation type current sensor comprises a single-core four-winding structure and a peripheral circuit;
The single-core four-winding structure comprises a magnetic core C, an exciting winding W ex, a primary side winding W p, a feedback winding W s and an induction winding W i, wherein the exciting winding W ex is used for generating alternating magnetic flux to enable a circuit to start to oscillate, the number of turns of the exciting winding W ex is N ex, the primary side winding W p is a winding through which primary side current to be measured flows, the number of turns of the primary side current N p is usually one, the feedback winding W s is a winding with closed loop feedback, the magnetic potential generated by the winding is used for counteracting the magnetic potential of the primary side current, the number of turns of the feedback winding W s is N s, the induction winding W i is used for inducing oscillating waves on the exciting winding, and the number of turns of the exciting winding N i is identical to the number of turns of the exciting winding N s.
The peripheral circuits comprise an excitation oscillation circuit ①, a signal processing circuit ②, an oscillation elimination circuit ③, grounding resistors R 1 and R 2, a sampling resistor R m and an MCU sampling display circuit ④;
the excitation oscillating circuit ① includes a comparator A1 and a comparator A2;
The end 1 of an exciting winding W ex in a single-magnetic-core four-winding structure is connected with the negative input end of a comparator A1 in an exciting oscillating circuit ①, the end 2 of the exciting winding W ex is connected with the output end of a comparator A2 in the exciting oscillating circuit, the end 9 in the exciting oscillating circuit ① is connected with the end 9 in a signal processing circuit ②, the end 3 in the signal processing circuit ② is connected with the end 3 of a feedback winding W s in the single-magnetic-core four-winding structure, the end 4 of the feedback winding W s is connected with one end of a grounding resistor R 2, the other end of the resistor R 2 is grounded, the end 5 and the end 6 of an induction winding W i are respectively connected with the two ends of a grounding resistor R 1, one end of a grounding resistor R 1 is grounded, and the end 7 and the end 8 of a primary winding W p are used for connecting currents to be tested;
The end 5 of the oscillation elimination circuit ③ is simultaneously connected with the end 5 of the induction winding W i and one end of the grounding resistor R 1, the end 4 of the oscillation elimination circuit ③ is simultaneously connected with the end 4 of the feedback winding W s and one end of the grounding resistor R 2, the end 10 of the oscillation elimination circuit ③ is connected with one end of the sampling resistor R m, the other end of the sampling resistor R m is grounded, and the MCU sampling display circuit ④ is connected with two ends of the sampling resistor R m.
A method for eliminating oscillation based on the single-core four-winding magnetic modulation type current sensor, comprising the following steps:
step one, constructing an excitation oscillating circuit according to the saturation characteristic of a magnetic core C;
Step two, adding a signal processing circuit on the basis of the step one;
and step three, adding an oscillation elimination circuit on the basis of the step two.
Preferably, in the first step, the exciting oscillating circuit is constructed according to the saturation characteristic of the magnetic core, and the working process is as follows:
The exciting oscillating circuit ① generates alternating exciting current i ex, the exciting magnetic core C is saturated alternately, and at the moment, the symmetry is destroyed by a magnetic field generated by direct current to be detected flowing through the primary side winding W p, so that the waveform of the exciting current i ex contains direct current components to be detected and distorted higher harmonics, and the exciting oscillating effect is achieved.
Preferably, in the second step, a signal processing circuit is added on the basis of the first step, and the working process is as follows:
In the first step, the waveform of the exciting current i ex which changes due to the flowing of the direct current to be measured is processed by the signal processing circuit ②, and the exciting current i ex is filtered by the signal processing circuit ②, The output is feedback current i s, the signal processing circuit ② filters the higher harmonic wave in the exciting current i ex in the step through a low-pass filter to enable only the direct current component to remain, the direct current component obtained after filtering is used as the control quantity of the integrating circuit and used for controlling the dynamic balance of the system, the magnetomotive force generated by feedback current i s output by the signal processing circuit ② in feedback winding W s is equal to the magnetomotive force generated by the current to be tested in primary winding W p in size but opposite in direction, the magnetomotive force is offset, and the current flowing in primary winding W p can be measured according to the value of feedback current i s and the ratio of the number of turns N s of feedback winding W s to the number of turns N p of primary winding W p.
Preferably, in the third step, an oscillation cancellation circuit is added on the basis of the second step, and the working process is as follows:
The exciting winding W ex is provided with an oscillating square wave, the feedback winding W s and the induction winding W i are provided with corresponding induction square waves due to the effect of a transformer, the numbers of turns of the two are equal, the amplitude and the phase of induction voltages on the two windings are the same, the voltage on the induction winding W i is U 1, the voltage on the feedback winding W s is U 2, the U 2 is inverted, and the two oscillation waves are added with the voltage on the induction winding W i as U 1 through an inverting addition circuit, so that the positive and negative of the two oscillation waves are counteracted.
The single-magnetic-core four-winding magnetic modulation type current sensor has the beneficial effects that the structure is special, the sensor comprises a single-magnetic-core four-winding structure and a peripheral circuit, the single-magnetic-core four-winding structure is integrated with the peripheral circuit through the matching of a magnetic core C, an exciting winding W ex, a primary side winding W p, a feedback winding W s and an induction winding W i, and the sensor is based on the sensor, the oscillation elimination method comprises the steps of firstly constructing an exciting oscillation circuit according to the saturation characteristic of the magnetic core, then filtering the excitation oscillation circuit through a signal processing circuit, sending the excitation oscillation circuit to an oscillation elimination circuit, and eliminating voltage oscillation on a sampling resistor in a feedback loop when the single-magnetic-core closed-loop feedback structure is eliminated through the oscillation elimination circuit. The invention solves the problem of voltage oscillation on the sampling resistor in the feedback loop when the self-oscillation fluxgate method is applied to a single magnetic core closed loop feedback structure.
Drawings
FIG. 1 is a schematic diagram of a schematic block diagram of a single-core four-winding magnetically modulated current sensor;
FIG. 2 is a schematic diagram of a single core four winding configuration;
FIG. 3 is a schematic diagram of the excitation oscillator circuit of FIG. 1;
FIG. 4 is a schematic diagram showing the connection between the exciting oscillating circuit in FIG. 3 and the exciting winding in FIG. 2;
FIG. 5 is a schematic waveform diagram of the excitation voltage V ex and the excitation current i ex after the circuit is vibrated;
FIG. 6 is a schematic diagram of the signal processing circuit of FIG. 1;
FIG. 7 is a schematic diagram of the oscillation cancellation circuit of FIG. 1;
Fig. 8 is a voltage waveform diagram of two input amounts U 1 and U 2 in the oscillation canceling circuit;
fig. 9 is an oscillation cancellation effect diagram of the oscillation cancellation circuit;
Fig. 10 is a graph showing the linearity of the sampled voltage U m and the current to be measured I p of the current sensor according to the present invention.
Detailed Description
Detailed description of the inventionin one embodiment, the present embodiment is specifically described with reference to fig. 1 to 9, and the single-core four-winding magnetic modulation type current sensor according to the present embodiment includes a single-core four-winding structure and a peripheral circuit;
The single-core four-winding structure comprises a magnetic core C, an exciting winding W ex, a primary side winding W p, a feedback winding W s and an induction winding W i, wherein the exciting winding W ex is used for generating alternating magnetic flux to enable a circuit to start to oscillate, the number of turns of the exciting winding W ex is N ex, the primary side winding W p is a winding through which primary side current to be measured flows, the number of turns of the primary side current N p is usually one, the feedback winding W s is a winding with closed loop feedback, the magnetic potential generated by the winding is used for counteracting the magnetic potential of the primary side current, the number of turns of the feedback winding W s is N s, the induction winding W i is used for inducing oscillating waves on the exciting winding, and the number of turns of the exciting winding N i is identical to the number of turns of the exciting winding N s.
The peripheral circuits comprise an excitation oscillation circuit ①, a signal processing circuit ②, an oscillation elimination circuit ③, grounding resistors R 1 and R 2, a sampling resistor R m and an MCU sampling display circuit ④;
the excitation oscillating circuit ① includes a comparator A1 and a comparator A2;
The end 1 of an exciting winding W ex in a single-magnetic-core four-winding structure is connected with the negative input end of a comparator A1 in an exciting oscillating circuit ①, the end 2 of the exciting winding W ex is connected with the output end of a comparator A2 in the exciting oscillating circuit, the end 9 in the exciting oscillating circuit ① is connected with the end 9 in a signal processing circuit ②, the end 3 in the signal processing circuit ② is connected with the end 3 of a feedback winding W s in the single-magnetic-core four-winding structure, the end 4 of the feedback winding W s is connected with one end of a grounding resistor R 2, the other end of the resistor R 2 is grounded, the end 5 and the end 6 of an induction winding W i are respectively connected with the two ends of a grounding resistor R 1, one end of a grounding resistor R 1 is grounded, and the end 7 and the end 8 of a primary winding W p are used for connecting currents to be tested;
The end 5 of the oscillation elimination circuit ③ is simultaneously connected with the end 5 of the induction winding W i and one end of the grounding resistor R 1, the end 4 of the oscillation elimination circuit ③ is simultaneously connected with the end 4 of the feedback winding W s and one end of the grounding resistor R 2, the end 10 of the oscillation elimination circuit ③ is connected with one end of the sampling resistor R m, the other end of the sampling resistor R m is grounded, and the MCU sampling display circuit ④ is connected with two ends of the sampling resistor R m.
Fig. 3, 6 and 7 are respectively an excitation oscillating circuit schematic diagram, a signal processing circuit schematic diagram and an oscillation eliminating circuit schematic diagram in fig. 1, and the connection relation of the elements in the 3 diagrams is shown in the figure.
The second embodiment is a method for eliminating oscillation of a single-core four-winding magnetic modulation current sensor according to the first embodiment, comprising the steps of:
step one, constructing an excitation oscillating circuit according to the saturation characteristic of a magnetic core C;
Step two, adding a signal processing circuit on the basis of the step one;
and step three, adding an oscillation elimination circuit on the basis of the step two.
In a third embodiment, the method for eliminating oscillation of the single-core four-winding magnetic modulation current sensor according to the second embodiment is further described, wherein in the first step, an excitation oscillating circuit is constructed according to saturation characteristics of a magnetic core, and the working process is as follows:
The exciting oscillating circuit ① generates alternating exciting current i ex, the exciting magnetic core C is saturated alternately, and at the moment, the symmetry is destroyed by a magnetic field generated by direct current to be detected flowing through the primary side winding W p, so that the waveform of the exciting current i ex contains direct current components to be detected and distorted higher harmonics, and the exciting oscillating effect is achieved.
In this embodiment, since the magnetization curve of the magnetic core C is symmetrical about the origin, the waveform of the exciting current i ex is also symmetrical about the zero point, and the average value is zero in one oscillation period, and the magnetic field generated by the direct current to be measured flowing through the primary winding W p breaks the symmetry, so that the waveform of the exciting current i ex includes the direct current component to be measured and the distorted higher harmonic wave, thereby completing the excitation oscillation effect.
The method of generating the alternating excitation current i ex according to the excitation oscillating circuit ① is described with reference to fig. 3 to 5:
As shown in fig. 3, the topology structure diagram has an upper branch and a lower branch, and the upper branch is formed by an output end of the comparator a 1, the exciting winding W ex, an internal resistance R ex of the exciting winding W ex, and a grounded resistor R 3. The lower leg is formed by the output of comparator a 1, resistor R 5, and a resistor R 4 connected to ground.
After the exciting oscillating circuit is connected with the exciting winding W ex, at the moment of just powering on, the positive and negative input ends of the comparator A 1 may drift due to zero point, the potential difference is not necessarily zero, and the exciting voltage V ex output by the comparator is positive or negative peak voltage. Assuming a positive peak voltage V H at the output, the lower leg rapidly establishes current through resistors R 4 and R 5 and reaches a stable value, the voltage at R 4 being
However, the current of the upper branch circuit cannot be suddenly changed and can only be slowly increased due to the exciting winding W ex serving as an inductor. When the exciting current i ex is increased to
At this time, the voltage across the resistor R 3 is equal to R 4. The exciting current i ex continues to increase, the voltage on the resistor R 3 is larger than R 4, the voltage of the negative input end of the comparator A 1 is larger than the voltage of the positive input end, and the output voltage of the comparator is converted from V H to-V H. The exciting current is reduced after the overturning until the exciting current is reduced
After this, the voltage at the positive input of the comparator a 1 will be greater than the voltage at the negative input, the output voltage of the comparator a 1 will be inverted to positive again, and the exciting current i ex will be changed from decreasing to increasing. The circuit repeats the previous process thereafter, performing periodic oscillations. The excitation voltage V ex is a square wave with positive and negative alternation, and the excitation current i ex is alternately increased and decreased. This process is shown in fig. 5.
The fourth embodiment is a further explanation of the method for eliminating oscillation of the single-core four-winding magnetic modulation current sensor according to the second embodiment, wherein the second step is to add a signal processing circuit on the basis of the first step, and the working process is as follows:
In the first step, the waveform of the exciting current i ex which changes due to the flowing of the direct current to be measured is processed by the signal processing circuit ②, and the exciting current i ex is filtered by the signal processing circuit ②, The integrating process is used for isolating the feedback winding W s from the integrating circuit and preventing the voltage on the feedback winding W s from influencing the integrating circuit, the signal processing circuit ② filters the higher harmonic wave in the exciting current i ex through a low-pass filter to enable only the direct current component to remain, the direct current component obtained after the filtering is used as the control quantity of the integrating circuit for controlling the dynamic balance of the system, the magnetomotive force generated by the feedback current i s output by the signal processing circuit ② in the feedback winding W s is equal to the magnetomotive force generated by the current to be detected in the primary winding W p but opposite in direction and offset each other, and the magnitude of the current flowing in the primary winding W p can be measured according to the value of the feedback current i s and the ratio of the turns N s of the feedback winding W s to the turns N p of the primary winding W p.
The exciting current i ex is filtered and integrated according to the signal processing circuit ②, and is output as a feedback current i s, in fig. 6, a resistor R 6 and a capacitor C 1 form a low-pass filter to filter out higher harmonics, a resistor R 7、R8、R9, a capacitor C 2 and a comparator a 3 form an integrating circuit, and a connection mode of the comparator a 4 forms a voltage follower to isolate the feedback winding W s from the integrating circuit.
In a fifth embodiment, the method for eliminating oscillation of the single-core four-winding magnetic modulation current sensor in the second embodiment is further described, and in the third step, an oscillation eliminating circuit is added on the basis of the second step, and the working process is as follows:
The exciting winding W ex is provided with an oscillating square wave, the feedback winding W s and the induction winding W i are provided with corresponding induction square waves due to the effect of a transformer, the numbers of turns of the two are equal, the amplitude and the phase of induction voltages on the two windings are the same, the voltage on the induction winding W i is U 1, the voltage on the feedback winding W s is U 2, the U 2 is inverted, and the two oscillation waves are added with the voltage on the induction winding W i as U 1 through an inverting addition circuit, so that the positive and negative of the two oscillation waves are counteracted.
In this embodiment, after the signal processing circuit constructed in the second step, the exciting current i ex is converted into the feedback current i s. The value of the feedback current i s can be obtained by the MCU sampling display circuit through the grounding resistor R 2 =1Ω. The voltage generated by the feedback current i s on R 2 is mutually coupled with the oscillating wave generated by the transformer effect, so that the sampling result of the MCU is affected. The oscillation cancellation circuit may cancel the oscillation wave on R 2. The waveforms are shown in fig. 8 (the upper curve is the voltage waveform on the feedback winding W s, the lower curve is the voltage waveform on the induction winding W i), the voltage on the induction winding W i is taken as U 1, the voltage on the feedback winding W s is taken as U 2, the U 2 is inverted, and the inverted addition operation circuit is added with the U 1, so that the positive and negative of the two oscillation waves are cancelled. The oscillation cancellation effect is shown in fig. 9 (square waveform is the voltage waveform on resistor R 2, slightly curved line is the voltage waveform on resistor R m), and the waveform of resistor R m is the result after the oscillation cancellation. The construction of the single-magnetic-core four-winding magnetic modulation type current sensor and the oscillation elimination method is completed.
In the oscillation eliminating circuit, the connection mode of the comparator A 5 forms a voltage follower and is used for taking out the voltage U 1 from the induction winding W i, the resistor R 10、R11、R12 and the comparator A 6 form an inverting proportional amplifying circuit and are used for taking out the reverse voltage from the resistor R 2, and the resistor R 13、R14、R15、R16 and the comparator A 7 form an inverting adding operation circuit and are used for adding the voltages U 1 and U 2 so as to achieve the purpose of eliminating the oscillation wave.
Theoretical calculation to eliminate oscillations:
Assuming the voltage on the sense winding W i is U 1, the voltage on the feedback winding W s is
U2＝U1+is·R2
The output value U m of the oscillation cancellation circuit is:
Um＝-(U1-U2)
=-(U1-U1-is·R2)
=is·R2
This output value U m can be sampled and displayed by the MCU via the sampling resistor R m, and since R 2 =1Ω, the sampled value U m is equal to the value of the feedback current i s.
As shown in fig. 8, in the simulation experiment, the number of turns N ex =500 of the exciting winding W ex, the number of turns N p =1 of the primary winding W p, the number of turns N s of the feedback winding W s, and the number of turns N i of the induction winding W i are all 100. When the primary current is 240A, the theoretical voltage of U 2 is a straight line with a value of 2.4V according to the ratio of the number of turns N s of the feedback winding W s to the number of turns N p of the primary winding W p, but the square wave from the transformer effect is coupled to become a waveform oscillating up and down at 2.4V. The voltage waveform of U 1 is a waveform oscillating up and down at 0V.
After the oscillation elimination circuit, the sampled voltage value U m shown in fig. 9,R m is a smooth curve and is stable at 2.4V. The waveforms of the sampling voltages U m and U 2 are compared, and the oscillation wave is almost eliminated.
According to the simulation experiment, the linear relation between the sampling voltage U m and the direct current I p to be tested is drawn as shown in fig. 10. The linearity is calculated according to the following formula:
Wherein Y is the maximum measurement range of the sensor. Δymax is the maximum absolute error between the sensor output and the ideal straight line, i.e., the maximum absolute error between the system output and the ideal straight line.
The linearity error was calculated to be 0.02%.
While the invention has been described with reference to several particular embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims (5)

1.一种单磁芯四绕组磁调制式电流传感器，其特征在于，该传感器包括单磁芯四绕组结构和外围电路；1. A single-core four-winding magnetic modulation current sensor, characterized in that the sensor includes a single-core four-winding structure and peripheral circuits; 单磁芯四绕组结构包括磁芯C、激磁绕组Wex、一次侧绕组Wp、反馈绕组Ws以及感应绕组Wi；激磁绕组Wex用于产生交变的磁通，使电路开始振荡，其匝数为Nex；一次侧绕组Wp是待测的一次侧电流流过的绕组，其匝数Np通常为一匝；反馈绕组Ws是闭环反馈的绕组，该绕组产生的磁势用于抵消一次侧电流的磁势，匝数为Ns；感应绕组Wi用于感应激磁绕组上的振荡波，其匝数Ni与Ns相同；The single-core, four-winding structure includes a magnetic core C, an excitation winding W ex , a primary winding W p , a feedback winding W s , and an induction winding W i . The excitation winding W ex is used to generate alternating magnetic flux, causing the circuit to oscillate, and its number of turns is N ex . The primary winding W p is the winding through which the primary current to be measured flows, and its number of turns N p is usually one turn. The feedback winding W s is the winding for closed-loop feedback, and the magnetic potential generated by this winding is used to offset the magnetic potential of the primary current. Its number of turns is N s . The induction winding W i is used to induce the oscillation wave on the excitation winding, and its number of turns Ni is the same as N s . 外围电路包括激磁振荡电路①、信号处理电路②、振荡消除电路③、接地电阻R1和R2、采样电阻Rm以及MCU采样显示电路④；The peripheral circuit includes the excitation oscillation circuit ①, the signal processing circuit ②, the oscillation elimination circuit ③, the grounding resistors R1 and R2 , the sampling resistor Rm , and the MCU sampling and display circuit ④; 所述激磁振荡电路①包括比较器A1和比较器A2；The excitation oscillation circuit ① includes comparator A1 and comparator A2; 单磁芯四绕组中的激磁绕组Wex的1号端连接激磁振荡电路①中比较器A1的负输入端；激磁绕组Wex的2号端连接激磁振荡电路中比较器A2的输出端；激磁振荡电路①中的9号端连接信号处理电路②中的9号端；信号处理电路②中的3号端连接单磁芯四绕组结构中的反馈绕组Ws的3号端；反馈绕组Ws的4端连接接地电阻R2的一端，电阻R2的另一端接地；感应绕组Wi的5号端和6号端分别连接接地电阻R1的两端，接地电阻R1的一端接地；一次侧绕组Wp的7号端和8号端用于连接待测的电流；Terminal 1 of the excitation winding Wex in the single-core four-winding structure is connected to the negative input terminal of comparator A1 in the excitation oscillation circuit ①; terminal 2 of the excitation winding Wex is connected to the output terminal of comparator A2 in the excitation oscillation circuit; terminal 9 in the excitation oscillation circuit ① is connected to terminal 9 in the signal processing circuit ②; terminal 3 in the signal processing circuit ② is connected to terminal 3 of the feedback winding Ws in the single-core four-winding structure; terminal 4 of the feedback winding Ws is connected to one end of the grounding resistor R2 , the other end of which is grounded; terminals 5 and 6 of the induction winding Wi are respectively connected to the two ends of the grounding resistor R1 , one end of which is grounded; terminals 7 and 8 of the primary winding Wp are used to connect to the current to be measured; 所述振荡消除电路③的5号端同时连接感应绕组Wi的5号端和接地电阻R1的一端；振荡消除电路③的4号端同时连接反馈绕组Ws的4号端和接地电阻R2的一端；振荡消除电路③的10号端连接采样电阻Rm的一端；采样电阻Rm的另一端接地；MCU采样显示电路④接在采样电阻Rm的两端。Terminal 5 of the oscillation elimination circuit ③ is simultaneously connected to terminal 5 of the induction winding Wi and one end of the grounding resistor R1 ; terminal 4 of the oscillation elimination circuit ③ is simultaneously connected to terminal 4 of the feedback winding Ws and one end of the grounding resistor R2 ; terminal 10 of the oscillation elimination circuit ③ is connected to one end of the sampling resistor Rm ; the other end of the sampling resistor Rm is grounded; and the MCU sampling and display circuit ④ is connected to both ends of the sampling resistor Rm . 2.基于权利要求1所述的一种单磁芯四绕组磁调制式电流传感器的消除振荡的方法，其特征在于，该方法包括下述步骤：2. A method for eliminating oscillation of a single-core four-winding magnetic modulation current sensor according to claim 1, characterized in that the method comprises the following steps: 步骤一：根据磁芯C的饱和特性构建激磁振荡电路；Step 1: Construct an excitation oscillation circuit based on the saturation characteristics of the magnetic core C; 步骤二：在步骤一的基础上加上信号处理电路；Step 2: Add signal processing circuit based on step 1; 步骤三：在步骤二的基础上增加振荡消除电路。Step 3: Add an oscillation elimination circuit based on step 2. 3.根据权利要求2所述的方法，其特征在于，步骤一中所述根据磁芯的饱和特性构建激磁振荡电路，其工作过程如下：3. The method according to claim 2, wherein the excitation oscillation circuit is constructed according to the saturation characteristics of the magnetic core in step 1, and the working process thereof is as follows: 由激磁振荡电路①产生交变的激磁电流iex，激励磁芯C交替饱和，此时一次侧绕组Wp中流过的待测直流产生的磁场会破坏该对称性，使得激磁电流iex的波形中包含待测直流分量以及畸变的高次谐波，起到激励振荡作用。The excitation oscillation circuit ① generates an alternating excitation current i ex , which excites the magnetic core C into alternate saturation. At this time, the magnetic field generated by the DC component to be measured flowing through the primary winding W p destroys the symmetry, causing the waveform of the excitation current i ex to contain the DC component to be measured and distorted higher harmonics, which acts as an excitation oscillation. 4.根据权利要求2所述的方法，其特征在于，步骤二中所述在步骤一的基础上加上信号处理电路，其工作过程如下：4. The method according to claim 2, wherein in step 2, a signal processing circuit is added to step 1, and the working process is as follows: 步骤一中因待测直流流过而产生变化的激磁电流iex的波形经信号处理电路②处理，信号处理电路②对激磁电流iex进行了滤波、积分处理，输出为反馈电流is；信号处理电路②通过低通滤波器滤除步骤一激磁电流iex中的高次谐波，使其仅剩下直流分量；滤除后所得的直流分量作为积分电路的控制量，用于控制系统的动态平衡；信号处理电路②输出的反馈电流is在反馈绕组Ws中产生的磁动势和待测电流在一次侧绕组Wp中产生的磁动势大小相等，但方向相反，相互抵消；又根据反馈电流is的值和反馈绕组Ws匝数Ns与一次侧绕组Wp的匝数Np之比，能够测出一次侧绕组Wp中流过的电流的大小。The waveform of the excitation current i ex , which changes due to the flow of the DC current to be measured in step 1, is processed by signal processing circuit ②. Signal processing circuit ② filters and integrates the excitation current i ex and outputs it as the feedback current i s . Signal processing circuit ② removes the higher harmonics in the excitation current i ex in step 1 through a low-pass filter, leaving only the DC component. The DC component obtained after filtering is used as the control variable of the integration circuit to control the dynamic balance of the system. The magnetomotive force generated by the feedback current i s output by signal processing circuit ② in the feedback winding W s and the magnetomotive force generated by the current to be measured in the primary winding W p are equal in magnitude but opposite in direction, and cancel each other out. Based on the value of the feedback current i s and the ratio of the number of turns N s of the feedback winding W s to the number of turns N p of the primary winding W p , the magnitude of the current flowing in the primary winding W p can be measured. 5.根据权利要求2所述的方法，其特征在于，步骤三中所述在步骤二的基础上增加振荡消除电路，其工作过程如下：5. The method according to claim 2, characterized in that in step 3, an oscillation elimination circuit is added on the basis of step 2, and its working process is as follows: 激磁绕组Wex上存在振荡方波，由于变压器效应，反馈绕组Ws和感应绕组Wi上均产生相应的感应方波；由于两者的匝数相等，两个绕组上的感应电压幅值以及相位相同，取感应绕组Wi上的电压为U1，反馈绕组Ws上的电压为U2，将U2取反，再经过反相加法运算电路与所述感应绕组Wi上的电压为U1相加，使两个振荡波正负相互抵消。There is an oscillating square wave on the excitation winding W ex . Due to the transformer effect, corresponding induced square waves are generated on the feedback winding Ws and the induction winding Wi . Since the number of turns of the two windings is equal, the induced voltage amplitude and phase on the two windings are the same. The voltage on the induction winding Wi is taken as U 1 , and the voltage on the feedback winding Ws is taken as U 2. U 2 is inverted and then added to the voltage on the induction winding Wi as U 1 through the inverting addition circuit, so that the positive and negative of the two oscillating waves cancel each other out.
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