CN116559513B - Integrating circuit and current sensor - Google Patents
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- CN116559513B CN116559513B CN202310346060.8A CN202310346060A CN116559513B CN 116559513 B CN116559513 B CN 116559513B CN 202310346060 A CN202310346060 A CN 202310346060A CN 116559513 B CN116559513 B CN 116559513B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/30—Structural combination of electric measuring instruments with basic electronic circuits, e.g. with amplifier
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The application provides an integrating circuit and a current sensor, which are applied to the technical field of electric measurement, wherein an in-phase input end of the integrating circuit receives a sampling voltage signal, an input end of the direct current servo feedback circuit is connected with an output end of the integrating circuit, an output end of the direct current servo feedback circuit is connected with an inverted input end of the integrating circuit, the direct current servo feedback circuit collects a target noise signal output by the integrating circuit and feeds the target noise signal back to the inverted input end of the integrating circuit so as to offset the target noise signal of the input end of the integrating circuit, and as the frequency of the target noise signal is lower than the minimum working frequency corresponding to the integrating circuit, the lower limit working frequency of the integrating circuit can be widened.
Description
Technical Field
The application relates to the technical field of electrical measurement, in particular to an integrating circuit and a current sensor.
Background
The current sensor based on the rogowski coil is common current detection equipment, and since the rogowski coil outputs a differential signal of the current to be detected, a subsequent circuit is required to integrate to restore the waveform of the current to be detected, and therefore, the integrating circuit is an important component circuit in the current sensor based on the rogowski coil.
The current sensor may be classified into a self-integrating rogowski coil current sensor and an external-integrating rogowski coil current sensor according to the difference of integration modes. For the external integration rogowski coil current sensor, an additional integration circuit processes a current differential signal output by the rogowski coil, the signal processing bandwidth is determined by the natural resonant frequency of the rogowski coil and the lower limit frequency of the integrator, and in practical application, in order to reduce the lower limit working frequency of the external integration rogowski coil current sensor, the lower limit frequency of the integrator needs to be as low as possible.
In order to meet the above requirements, the prior art provides an integrating circuit shown in fig. 1, in which a resistor R f forms a feedback circuit, a voltage signal is fed back to an input end of an operational amplifier, an analog electronic switch is added in the feedback circuit, a proper pulse width modulation signal is input at a control end to control on-off of the analog electronic switch, and an equivalent resistance value of the feedback resistor at two ends of an integrating capacitor is changed, so that the integrating characteristic of the circuit is changed, and the defect of limited low-frequency integral frequency division rate of the integrating circuit is overcome.
However, because the analog electronic switch is introduced into the integrating circuit, a control circuit for outputting a pulse width modulation signal is also required to be arranged for the analog electronic switch, the complexity of the system is obviously increased, the whole cost of the equipment is high, and the system stability is poor.
Disclosure of Invention
In view of this, the present application is directed to providing an integrating circuit and a current sensor, which are capable of reducing the complexity and cost of the system and improving the stability of the system without providing an analog electronic switch and a corresponding control circuit while reducing the lower limit operating frequency of the integrating circuit.
In a first aspect, the present application provides an integrating circuit comprising: an integrating main circuit and a DC servo feedback circuit, wherein,
The non-inverting input end of the integrating main circuit receives a sampling voltage signal;
The input end of the direct current servo feedback circuit is connected with the output end of the integration main circuit, and the output end of the direct current servo feedback circuit is connected with the inverting input end of the integration main circuit;
the direct current servo feedback circuit is used for collecting a target noise signal output by the integration main circuit and feeding the target noise signal back to the inverting input end of the integration main circuit so as to offset the target noise signal of the input end of the integration main circuit;
the frequency of the target noise signal is lower than the lowest working frequency corresponding to the integrated main circuit.
In one possible implementation, the dc servo feedback circuit includes: a sampling circuit and a feedback main circuit, wherein,
The input end of the sampling circuit is used as the input end of the direct current servo feedback circuit, and the output end of the sampling circuit is connected with the input end of the feedback main circuit;
The output end of the feedback main circuit is used as the output end of the direct current servo feedback circuit;
the sampling circuit is used for sampling the target noise signal output by the integration main circuit according to a preset proportion to obtain an intermediate noise signal;
And the feedback main circuit is used for amplifying the intermediate noise signal so as to restore and obtain the target noise signal.
In one possible implementation, the sampling circuit includes: a first sampling resistor and a second sampling resistor, wherein,
One end of the first sampling resistor is used as an input end of the sampling circuit, and the other end of the first sampling resistor is connected with one end of the second sampling resistor;
the other end of the second sampling resistor is grounded;
And the connection point of the first sampling resistor and the second sampling resistor is used as the output end of the sampling circuit.
In one possible implementation, the feedback main circuit includes: a first operational amplifier, a first feedback resistor and a feedback capacitor, wherein,
The non-inverting input end of the first operational amplifier is connected with the output end of the sampling circuit, and the inverting input end of the first operational amplifier is connected with one end of the first feedback resistor;
The other end of the first feedback resistor is grounded;
the feedback capacitor is connected in series between the inverting input end of the first operational amplifier and the output end of the first operational amplifier;
the output end of the first operational amplifier is used as the output end of the feedback main circuit.
In one possible implementation, the feedback main circuit further comprises an output circuit, wherein,
The output circuit comprises a second feedback resistor, a third feedback resistor and a fourth feedback resistor, wherein,
One end of the second feedback resistor is used as an output end of the feedback main circuit, and the other end of the second feedback resistor is connected with one end of the third feedback resistor;
the other end of the third feedback resistor is connected with the output end of the first operational amplifier;
One end of the fourth feedback resistor is connected with the connection point of the second feedback resistor and the third feedback resistor, and the other end of the fourth feedback resistor is grounded.
In one possible implementation, the integrating main circuit includes: a second operational amplifier, a first integrating capacitor and a first integrating resistor, wherein,
The non-inverting input end of the second operational amplifier is used as the non-inverting input end of the integrating main circuit, and the output end of the second operational amplifier is used as the output end of the integrating main circuit;
the inverting input end of the second operational amplifier is connected with one end of the first integrating resistor, and the other end of the first integrating resistor is grounded;
The first integrating capacitor is connected in series between the inverting input end and the output end of the second operational amplifier.
In a second aspect, the present invention provides a current sensor comprising: a current sensing circuit and an integrating circuit according to any one of the first aspects of the present invention;
The output end of the current sensing circuit is connected with the non-inverting input end of an integrating main circuit in the integrating circuit;
The current sensing circuit is used for converting a current signal to be detected into a sampling voltage signal.
In one possible embodiment, the current sensing circuit includes: the current sensing circuit comprises a Rogowski coil and output resistors connected in series with two ends of the Rogowski coil, wherein one end of each output resistor is used as an output end of the current sensing circuit.
In one possible implementation manner, the current sensor provided in the second aspect of the present invention further includes: a high-frequency integrated circuit, wherein,
The input end of the high-frequency integrating circuit is connected with the current sensing circuit, and the output end of the high-frequency integrating circuit is connected with the integrating circuit;
The high-frequency integrating circuit is used for carrying out integral operation on a voltage signal with the frequency higher than a preset frequency in the sampling voltage signals output by the current sensing circuit.
In one possible embodiment, the high frequency integrating circuit includes: a second integrating resistor and a second integrating capacitor, wherein,
One end of the second integrating resistor is connected with one end of the output resistor, and the other end of the second integrating resistor is connected with one end of the second integrating capacitor;
the other end of the second integrating capacitor is connected with the other end of the output resistor;
and the connection point of the second integrating resistor and the second integrating capacitor is used as the output end of the high-frequency integrating circuit.
Based on the above, the integrating circuit provided by the present application includes: the input end of the direct current servo feedback circuit is connected with the output end of the integration main circuit, the output end of the direct current servo feedback circuit is connected with the opposite phase input end of the integration main circuit, the direct current servo feedback circuit collects target noise signals output by the integration main circuit and feeds the target noise signals back to the opposite phase input end of the integration main circuit so as to offset the target noise signals at the input end of the integration main circuit, and the frequency of the target noise signals is lower than the lowest working frequency corresponding to the integration main circuit, so that the lower limit working frequency of the integration circuit can be widened.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a circuit topology of an integrating circuit of the prior art.
Fig. 2 is a circuit block diagram of an integrating circuit according to an embodiment of the present invention.
Fig. 3 is a circuit topology diagram of an integrating circuit according to an embodiment of the present invention.
Fig. 4 is a circuit topology diagram of another integrating circuit provided by an embodiment of the present invention.
Fig. 5 is a circuit topology diagram of a current sensor according to an embodiment of the present invention.
Fig. 6 is a circuit topology of another current sensor provided by an embodiment of the present invention.
Fig. 7 is a schematic diagram of simulation results of a current sensor according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The current sensor based on the Rogowski coil is commonly called as a Rogowski coil current sensor, is a current detection device commonly used in the operation detection of an electrical system, and is widely applied because the Rogowski coil does not have an iron core, does not have the magnetic saturation problem, and is convenient to open and close.
The rogowski coil mainly applies the electromagnetic induction principle, and the differential signal of the measured current is output, and the waveform of the measured current can be restored by integrating the follow-up circuit, so that the integrating circuit is an important component circuit in the rogowski coil current sensor. The rogowski coil current sensor can be classified into a self-integrating rogowski coil current sensor and an external integrating rogowski coil current sensor according to different integration modes. For the external integration rogowski coil current sensor, an additional integration circuit processes a current differential signal output by the rogowski coil, and the bandwidth of the current differential signal is determined by the natural resonant frequency of the rogowski coil and the lower limit frequency of an integrator. Therefore, in practical applications, to reduce the lower limit operating frequency of the external integration rogowski coil current sensor, the lower limit frequency of the integrator needs to be as low as possible.
The prior art shown in fig. 1 provides an integrating circuit, in which an operational amplifier 1, a resistor Rs and a capacitor C form a main integrating circuit, a resistor R f forms a feedback circuit, a voltage signal is fed back to an input end of the operational amplifier, an analog electronic switch is added in the feedback circuit, a proper pulse width modulation signal is input at a control end so as to control on-off of the analog electronic switch, and equivalent resistance values of feedback resistors at two ends of the integrating capacitor are changed, so that the integrating characteristic of the circuit is changed, and the defect of limited low-frequency product frequency division rate of the integrating circuit is overcome.
However, when the integrating circuit shown in fig. 1 is in operation, because the analog electronic switch S is introduced into the circuit, the on-off of the analog electronic switch S needs to be controlled by an independent pulse width modulation signal, so that in practical application, a control circuit for outputting the pulse width modulation signal is also required to be arranged for the analog electronic switch, and strict requirements are also required on the duty ratio of the pulse width modulation signal, which can definitely increase the complexity of the system, the overall cost of the equipment is high, and the stability of the system is poor.
In order to solve the problem, the invention provides an integrating circuit which comprises an integrating main circuit and a direct current servo feedback circuit, wherein a target noise signal with the frequency lower than the lowest working frequency of the integrating main circuit is fed back to an inverting input end of the integrating main circuit through the direct current servo feedback main circuit so as to offset the target noise signal of the input end of the integrating main circuit, and the frequency of the target noise signal is lower than the lowest working frequency corresponding to the integrating main circuit, so that the lower limit working frequency of the integrating circuit can be widened.
Based on the foregoing, referring to fig. 2, an integrating circuit provided in an embodiment of the present invention includes: an integrating main circuit 10 and a DC servo feedback circuit 20, wherein,
The integrating main circuit 10 includes: a second operational amplifier X2, a first integrating capacitor C2 and a first integrating resistor R7. Specifically, the non-inverting input terminal of the second operational amplifier X2 is used as the non-inverting input terminal of the integrating main circuit 10, and in practical applications, the non-inverting input terminal of the integrating main circuit 10 is typically connected to a rogowski coil (not shown in fig. 2) and receives the sampled voltage signal Ui output by the rogowski coil. It can be understood that the sampled voltage signal Ui described in this embodiment is obtained by electromagnetic conversion based on the current to be measured, and is a voltage signal obtained by differentiating the current to be measured. The inverting input terminal of the second operational amplifier X2 is connected to one end of the first integrating resistor R7, and the other end of the first integrating resistor R7 is grounded. The first integrating capacitor C2 is connected in series between the inverting input terminal and the output terminal of the second operational amplifier X2. Further, the output end of the second operational amplifier X2 is used as the output end of the integrating main circuit 10, and the final detection voltage signal Uo is output outwards through the output end of the integrating main circuit 10, so that the waveform of the current to be measured can be accurately reproduced by the final detection voltage signal output by the integrating main circuit 10 based on the basic working principle of the rogowski coil current sensor, and further, the current measurement result is obtained.
Based on the basic configuration of the integrating main circuit 10, the input terminal of the dc servo feedback circuit 20 is connected to the output terminal of the integrating main circuit 10, and the output terminal is connected to the inverting input terminal of the integrating main circuit 10. In the embodiment of the present invention, the dc servo feedback circuit 20 is mainly used for suppressing the bias voltage and the low frequency noise of the second operational amplifier X2, so the dc servo feedback circuit 20 can be regarded as a low frequency amplifying circuit. The dc servo feedback circuit 20 collects a target noise signal output by the integrating main circuit 10, where the target noise signal is a signal with a frequency lower than the lowest operating frequency corresponding to the integrating main circuit 10, and when the voltage signal output by the integrating main circuit 10 contains the target noise signal, the dc servo feedback circuit 20 amplifies the target noise signal and feeds back the amplified target noise signal to the inverting input terminal of the integrating main circuit 10, so as to cancel the target noise signal contained in the sampled voltage signal at the non-inverting input terminal of the integrating main circuit 10.
Further, the voltage signal with a frequency higher than the lowest operating frequency corresponding to the integrating main circuit 10 included in the output voltage of the second operational amplifier X2 is cut off by the dc servo feedback circuit 20 and is not fed back to the input end of the integrating main circuit 10, so that no influence is caused on the normal sampling voltage signal received by the integrating main circuit 10.
In summary, according to the integrating circuit provided by the embodiment of the invention, the direct current servo feedback circuit collects the target noise signal output by the integrating main circuit and feeds the target noise signal back to the inverting input end of the integrating main circuit so as to offset the target noise signal at the input end of the integrating main circuit, and because the frequency of the target noise signal is lower than the lowest working frequency corresponding to the integrating main circuit, the lower limit working frequency of the integrating circuit can be widened.
Further, the present invention provides another integrating circuit, and referring to fig. 3, the present embodiment further provides an alternative implementation manner of the dc servo feedback circuit based on the embodiment shown in fig. 2.
Specifically, in this embodiment, the dc servo feedback circuit includes: the sampling circuit comprises a first sampling resistor R1 and a second sampling resistor R2; the feedback main circuit comprises a first operational amplifier X1, a first feedback resistor R3 and a feedback capacitor C1.
Specifically, one end of the first sampling resistor R1 is used as an input end of a sampling circuit, correspondingly, the input end of the sampling circuit is simultaneously used as an input end of the direct current servo feedback circuit 20, and is connected with an output end of the integrating main circuit 10, the other end of the first sampling resistor R1 is connected with one end of the second sampling resistor R2, and the other end of the second sampling resistor R2 is grounded. The connection point of the first sampling resistor R1 and the second sampling resistor R2 is used as an output end of the sampling circuit and is connected with an input end of the feedback main circuit, namely a non-inverting input end of the first operational amplifier X1.
The non-inverting input end of the first operational amplifier X1 is used as the input end of the feedback main circuit and is connected with the output end of the sampling circuit, the inverting input end of the first operational amplifier X1 is connected with one end of the first feedback resistor R3, and the other end of the first feedback resistor R3 is grounded. Further, the feedback capacitor C1 is connected in series between the inverting input terminal of the first operational amplifier X1 and the output terminal of the first operational amplifier X1. The output of the first operational amplifier X1 is connected as the output of the feedback main circuit to the inverting input of the second operational amplifier X2 in the integrating main circuit 10.
Based on the connection relation and the specific circuit topology, the sampling circuit is used for sampling the target noise signal output by the integral main circuit according to a preset proportion to obtain an intermediate noise signal, and the feedback main circuit receives the intermediate noise signal and amplifies the intermediate noise signal to restore the intermediate noise signal to obtain the target noise signal.
The following signal transmission process and the working principle of the integrating circuit can be realized by referring to the foregoing, and will not be repeated here.
Further, referring to fig. 4, the feedback main circuit in the dc servo feedback circuit 20 may further include an output circuit including a second feedback resistor R4, a third feedback resistor R5, and a fourth feedback resistor R6. Specifically, one end of the second feedback resistor R4 is used as an output end of the feedback main circuit and is connected to an inverting input end of the second operational amplifier in the integrating main circuit 10, the other end of the second feedback resistor R4 is connected to one end of the third feedback resistor R5, and the other end of the third feedback resistor R5 is connected to an output end of the first operational amplifier X1. One end of the fourth feedback resistor R6 is connected with the connection point of the second feedback resistor R4 and the third feedback resistor R5, and the other end of the fourth feedback resistor R6 is grounded.
In summary, as can be seen from the embodiments shown in fig. 3 and fig. 4, compared with the prior art, the integrating circuit provided by the application does not need to be provided with an analog electronic switch and a corresponding control circuit, has a simple working process, can reduce the complexity and cost of the system on the premise of reducing the lower limit working frequency of the integrating circuit, is beneficial to improving the stability of the system, can realize the integration of ultralow frequency signals, and solves the problem of insufficient working frequency of the rogowski coil current sensor due to the lack of the performance of the integrating circuit.
Furthermore, the integrating circuits provided by the embodiments are all composed of analog electronic devices, the direct current servo feedback circuit is a real-time feedback process, and compared with digital integration, the integrating circuits provided by the application have higher response speed, are suitable for application requirements of higher frequency bands, can enable the sensor to normally work in a current measuring environment far lower than power frequency, greatly expand the working frequency band of the Rogowski coil current sensor, and widen the application range of the current sensor. In addition, the circuit is simpler, does not comprise a microprocessor and an analog power electronic switch, and has strong economical efficiency and practicability.
The present invention also provides a current sensor based on the integrating circuit provided in any of the foregoing embodiments, referring to fig. 5, where the current sensor provided in the present invention includes a current sensing circuit 30 and the integrating circuit provided in any of the foregoing embodiments (fig. 5 is an example of the integrating circuit provided in the embodiment shown in fig. 4).
In this embodiment, the current sensing circuit 30 includes a rogowski coil L and an output resistor Rm connected in series to two ends of the rogowski coil L, a current i (t) to be measured flows through the rogowski coil L, a corresponding sensing current is generated inside the rogowski coil L based on an electromagnetic induction principle, and when the sensing current flows through the output resistor Rm, a corresponding sampling voltage signal is generated at two ends of the output resistor Rm due to the closed loop formed by the rogowski coil L and the output resistor Rm, and one end of the output resistor Rm is used as an output end of the current sensing circuit 30 and is connected with an input end of the integrating main circuit 10 to output the sampling voltage signal to the integrating main circuit 10.
Further, on the basis of the embodiment shown in fig. 5, the current sensor according to the embodiment of the present invention further includes a high-frequency integrated circuit 40. As shown in fig. 6, the high-frequency integrating circuit 40 includes a second integrating resistor R8 and a second integrating capacitor C3, wherein one end of the second integrating resistor R8 is connected to one end of the output resistor Rm, the other end of the second integrating resistor R8 is connected to one end of the second integrating capacitor C3, and further, the other end of the second integrating capacitor C3 is connected to the other end of the output resistor Rm. As can be seen in fig. 6, the second integrating resistor R8 and one end of the second integrating capacitor C3 are commonly used as the input terminal of the high-frequency integrating circuit 40, and are connected to the current sensing circuit 30. The connection point of the second integrating resistor R8 and the second integrating capacitor C3 is used as the output end of the high-frequency integrating circuit 40 and is connected with the non-inverting input end of the main integrating circuit 10 in the integrating circuit.
The high-frequency integrating circuit 40 can perform an integrating operation on a voltage signal with a frequency higher than a preset frequency among the sampled voltage signals output by the current sensing circuit 30. That is, the integrating circuit according to any of the embodiments of the present application can integrate the low-frequency signal output from the current sensing circuit as an active integrating circuit, and the high-frequency integrating circuit 40 can integrate the high-frequency signal output from the current sensing circuit as a passive integrating circuit. The high frequency integrating circuit 40 is matched with the integrating circuit provided by the application, so that the working bandwidth of the current sensor can be further widened.
Note that L0, R0, and C0 shown in fig. 6 are all equivalent circuit parameters of the rogowski coil. On the premise of this, in the current sensor provided in the embodiment shown in fig. 6, the matching resistance rm=500Ω of the rogowski coil is set assuming that m=35nh, the self inductance l0=14μh, the internal resistance r0=1.9Ω, and the distributed capacitance c0=100deg pF; according to the foregoing and the corresponding circuit topology of fig. 6, the following constraints exist for integrating circuit parameter selection: r8c3=r7c2, 6r1c2=r1c5, the cut-off frequency f Li should be less than the required value. Setting the 3dB lower limit frequency of the sensor to be lower than 1Hz and the 3dB upper limit frequency to be higher than 4MHz, the specific circuit parameters are as follows: r8=10kΩ, r7=3.5kΩ, r1=500kΩ, r4=150kΩ, r2=2kΩ, r5=150kΩ, r3=150kΩ, r6=150kΩ, c3=700 pf, c2=2nf, c1=2.2uf.
According to the parameters and the circuit diagram shown in fig. 6, the current sensor is designed, the corresponding working frequency band can be as shown in fig. 7, the amplitude-frequency characteristic curve is flat in the working frequency band, and compared with the rogowski coil current sensor adopting the traditional integrator, the rogowski coil current sensor adopting the integrating circuit has wider working frequency band.
Those skilled in the art will appreciate that various modifications and improvements can be made to the disclosure. For example, the various devices or components described above may be implemented in hardware, or may be implemented in software, firmware, or a combination of some or all of the three.
Further, while the present disclosure makes various references to certain elements in a system according to embodiments of the present disclosure, any number of different elements may be used and run on a client and/or server. The units are merely illustrative and different aspects of the systems and methods may use different units.
A flowchart is used in this disclosure to describe the steps of a method according to an embodiment of the present disclosure. It should be understood that the steps that follow or before do not have to be performed in exact order. Rather, the various steps may be processed in reverse order or simultaneously. Also, other operations may be added to these processes.
Those of ordinary skill in the art will appreciate that all or a portion of the steps of the methods described above may be performed by a computer program that instructs associated hardware, and that the program may be stored on a computer readable storage medium, such as a read only memory, etc. Alternatively, all or part of the steps of the above embodiments may be implemented using one or more integrated circuits. Accordingly, each module/unit in the above embodiment may be implemented in the form of hardware, or may be implemented in the form of a software functional module. The present disclosure is not limited to any specific form of combination of hardware and software.
Unless defined otherwise, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The foregoing is illustrative of the present disclosure and is not to be construed as limiting thereof. Although a few exemplary embodiments of this disclosure have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this disclosure. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the claims. It is to be understood that the foregoing is illustrative of the present disclosure and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The disclosure is defined by the claims and their equivalents.
Claims (8)
1. An integrating circuit, comprising: an integrating main circuit and a DC servo feedback circuit, wherein,
The non-inverting input end of the integrating main circuit receives a sampling voltage signal;
The input end of the direct current servo feedback circuit is connected with the output end of the integration main circuit, and the output end of the direct current servo feedback circuit is connected with the inverting input end of the integration main circuit;
the direct current servo feedback circuit is used for collecting a target noise signal output by the integration main circuit and feeding the target noise signal back to the inverting input end of the integration main circuit so as to offset the target noise signal of the input end of the integration main circuit;
the frequency of the target noise signal is lower than the lowest working frequency corresponding to the integral main circuit;
the direct current servo feedback circuit comprises: a sampling circuit and a feedback main circuit, wherein,
The input end of the sampling circuit is used as the input end of the direct current servo feedback circuit, and the output end of the sampling circuit is connected with the input end of the feedback main circuit;
The output end of the feedback main circuit is used as the output end of the direct current servo feedback circuit;
the sampling circuit is used for sampling the target noise signal output by the integration main circuit according to a preset proportion to obtain an intermediate noise signal;
The feedback main circuit is used for amplifying the intermediate noise signal to restore and obtain the target noise signal;
The feedback main circuit includes: a first operational amplifier, a first feedback resistor and a feedback capacitor, wherein,
The non-inverting input end of the first operational amplifier is connected with the output end of the sampling circuit, and the inverting input end of the first operational amplifier is connected with one end of the first feedback resistor;
The other end of the first feedback resistor is grounded;
the feedback capacitor is connected in series between the inverting input end of the first operational amplifier and the output end of the first operational amplifier;
the output end of the first operational amplifier is used as the output end of the feedback main circuit.
2. The integrating circuit of claim 1, wherein said sampling circuit comprises: a first sampling resistor and a second sampling resistor, wherein,
One end of the first sampling resistor is used as an input end of the sampling circuit, and the other end of the first sampling resistor is connected with one end of the second sampling resistor;
the other end of the second sampling resistor is grounded;
And the connection point of the first sampling resistor and the second sampling resistor is used as the output end of the sampling circuit.
3. The integrating circuit of claim 1 wherein said feedback main circuit further comprises an output circuit, wherein,
The output circuit comprises a second feedback resistor, a third feedback resistor and a fourth feedback resistor, wherein,
One end of the second feedback resistor is used as an output end of the feedback main circuit, and the other end of the second feedback resistor is connected with one end of the third feedback resistor;
the other end of the third feedback resistor is connected with the output end of the first operational amplifier;
One end of the fourth feedback resistor is connected with the connection point of the second feedback resistor and the third feedback resistor, and the other end of the fourth feedback resistor is grounded.
4. An integrating circuit as claimed in any one of claims 1 to 3, wherein the integrating main circuit comprises: a second operational amplifier, a first integrating capacitor and a first integrating resistor, wherein,
The non-inverting input end of the second operational amplifier is used as the non-inverting input end of the integrating main circuit, and the output end of the second operational amplifier is used as the output end of the integrating main circuit;
the inverting input end of the second operational amplifier is connected with one end of the first integrating resistor, and the other end of the first integrating resistor is grounded;
The first integrating capacitor is connected in series between the inverting input end and the output end of the second operational amplifier.
5. A current sensor, comprising: a current sensing circuit and an integrating circuit as claimed in any one of claims 1 to 4;
The output end of the current sensing circuit is connected with the non-inverting input end of an integrating main circuit in the integrating circuit;
The current sensing circuit is used for converting a current signal to be detected into a sampling voltage signal.
6. The current sensor of claim 5, wherein the current sensing circuit comprises: the current sensing circuit comprises a Rogowski coil and output resistors connected in series with two ends of the Rogowski coil, wherein one end of each output resistor is used as an output end of the current sensing circuit.
7. The current sensor of claim 6, further comprising: a high-frequency integrated circuit, wherein,
The input end of the high-frequency integrating circuit is connected with the current sensing circuit, and the output end of the high-frequency integrating circuit is connected with the integrating circuit;
The high-frequency integrating circuit is used for carrying out integral operation on a voltage signal with the frequency higher than a preset frequency in the sampling voltage signals output by the current sensing circuit.
8. The current sensor of claim 7, wherein the high frequency integration circuit comprises: a second integrating resistor and a second integrating capacitor, wherein,
One end of the second integrating resistor is connected with one end of the output resistor, and the other end of the second integrating resistor is connected with one end of the second integrating capacitor;
the other end of the second integrating capacitor is connected with the other end of the output resistor;
and the connection point of the second integrating resistor and the second integrating capacitor is used as the output end of the high-frequency integrating circuit.
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| CN105375894A (en) * | 2015-10-09 | 2016-03-02 | 中国船舶重工集团公司第七一〇研究所 | High-gain low-noise weak pulse current signal amplification circuit |
| CN106546798A (en) * | 2016-11-23 | 2017-03-29 | 国家电网公司 | A kind of analogue integrator and electronic current transducer Acquisition Circuit |
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| CA2333616A1 (en) * | 1998-05-07 | 1999-11-11 | Airpax Corporation, L.L.C. | Ac current sensor having high accuracy and large bandwidth |
| CN108418560B (en) * | 2018-03-30 | 2023-08-04 | 福州大学 | Readout circuit applied to Hall current sensor |
| CN213518035U (en) * | 2020-11-10 | 2021-06-22 | 武汉安检电气有限公司 | Multifunctional current transformer |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105375894A (en) * | 2015-10-09 | 2016-03-02 | 中国船舶重工集团公司第七一〇研究所 | High-gain low-noise weak pulse current signal amplification circuit |
| CN106546798A (en) * | 2016-11-23 | 2017-03-29 | 国家电网公司 | A kind of analogue integrator and electronic current transducer Acquisition Circuit |
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