CN204044224U - A kind of alterating and direct current flow sensor - Google Patents
A kind of alterating and direct current flow sensor Download PDFInfo
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- CN204044224U CN204044224U CN201420413079.6U CN201420413079U CN204044224U CN 204044224 U CN204044224 U CN 204044224U CN 201420413079 U CN201420413079 U CN 201420413079U CN 204044224 U CN204044224 U CN 204044224U
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Abstract
The utility model relates to a kind of alterating and direct current flow sensor, it comprises: high magnetic conduction transformer unit, pumping signal generating unit, direct current signal detecting unit, restoring circuit unit, AC signal processing unit and power amplification unit, wherein, described high magnetic conduction transformer unit comprises: the first magnetic core independent of each other and the second magnetic core; Be wound on the first field coil on described first magnetic core and the second magnetic core and the second field coil respectively; 3rd magnetic core, itself and described first magnetic core and the second magnetic core stack together, to form a whole magnetic core; And the primary coil, secondary coil and the ancillary coil that are wound on described whole magnetic core.The utility model significantly improves the performance of sensor, and have that low in energy consumption, diamagnetic interference performance is strong, structure is simple, lightweight, fast response time, highly sensitive, interchangeability good and install, calibration, debugging, safeguard the advantages such as all very convenient.
Description
Technical field
The utility model relates to a kind of alterating and direct current flow sensor.
Background technology
At DC transmission system, RHVC, ups power, inverter type welder, metallide, numerically-controlled machine, microcomputer detecting system, accelerator operation, grid monitoring system with need in the every field of isolation detection electric current, accurate detection and control DC current is the basic assurance of device security reliability service and the problem that first will solve.
At present, comprise for the means measuring electric current: current measuring method and the equipment such as current comparator, D.C mutual-inductor, direct current instrument transformer, shunt, the equipment of above different size all can commercially find.But the equipment based on above-mentioned current measuring method is often due to method itself or use occasion condition, cost restriction, and shows many deficiencies in the current measurement of high precision, wide region; Such as: current comparator to the frequency limitation of tested electric current at about 50Hz; Mutual inductor has restriction to tested electric current AC and DC composition; There is big current and generate heat seriously and the problem of not isolating in shunt.As can be seen here, the method and apparatus of above-mentioned several measurement electric current limits its measuring accuracy, measurement noises level etc. in principle, and in other words, in high precision, wide region current measurement, the said equipment is not competent measurement requirement apparently.
Meanwhile, equipment and the method for some measurement electric currents based on the physical influence such as magneto-optic effect and nuclear magnetic resonance is have also appeared in prior art, wherein, magneto-optic effect measure electric current equipment can on the south Swiss Airways sky NAE-GL series all-fiber electronic current transformer be example, but magneto-optic effect surveys current limited in the birefringence effect of magneto-optic glass, therefore both reduced measuring accuracy and turn increased equipment cost, expensive price makes it apply and is confined to power transmission and transformation industry.And the measurement current methods based on nuclear magnetic resonance be only used for measure absolute ampere time laboratory method or measurement standard, therefore not adopt by large-scale commercial production.
Comparatively speaking, transformer type current transformer due to its have dielectric strength high, operate the advantages such as reliable, cheap, be extensively widely used in social production practice in.The ultimate principle of transformer type current transformer is: when excitatory ampere-turn is zero, the change of secondary ampere-turn can reflect the ampere-turn change of former limit completely, error is zero, magnetic core is now in " accurate Zero flux " state, it works in the initial segment (i.e. linearity range) of magnetization curve, and at this moment, current transformer exports and would not be distorted by shape, the good linearity can be kept, be commonly called as " Zero flux " principle.Therefore, if transformer core can be made to be in Zero flux state all the time, the error of current transformer can just fundamentally be eliminated.But, from the principle of work of mutual inductor, rely on mutual inductor self not realize Zero flux, compensation or the adjustment of external condition must be leaned on.
For this reason, occurred again magnetrol comparator (hereinafter referred to as magnetrol) and magnetic modulator comparator (hereinafter referred to as magnetic modulator) in prior art, they all adopt " Zero flux state ", and principle carries out current measurement.But magnetrol due to its complex structure, heaviness, thus limits the application of its miniaturization and high-acruracy survey.And common magnetic modulator comprises single magnetic core and bimag two kinds, traditional magnetic modulating current testing requirement two magnetic cores must have identical physical dimension and on all four magnetic characteristic, and easily there is false equilibrium point in the open loop characteristic curve of magnetic modulator, thus reduce magnetic modulator reliability of operation, therefore, application and the popularization of magnetic modulator is limited.
Utility model content
In order to solve above-mentioned prior art Problems existing, the utility model aims to provide a kind of alterating and direct current flow sensor of high precision Magnetic isolation, to be formed " accurate Zero flux state ", thus realizes the accurate detection of electric current.
A kind of alterating and direct current flow sensor described in the utility model, it comprises:
High magnetic conduction transformer unit, it comprises:
First magnetic core independent of each other and the second magnetic core;
Be wound on the first field coil on described first magnetic core and the second magnetic core and the second field coil respectively;
3rd magnetic core, itself and described first magnetic core and the second magnetic core stack together, to form a whole magnetic core; And
Be wound on the primary coil on described whole magnetic core, secondary coil and ancillary coil, wherein, the number of turn of described primary coil is Np, and described primary coil receives the measured DC of peripheral input or tested alternating current, the number of turn of described secondary coil is Ns, and described secondary coil exports the DC current or alternating current that record;
Pumping signal generating unit, it is connected with described first field coil and described second field coil, to provide the exciting current of two phase differential 180 ° respectively to described first field coil and the second field coil;
Direct current signal detecting unit, it is connected with described second field coil, with when described primary coil receives described measured DC, receive the corresponding asymmetric magnetization signal that described second field coil exports, and this asymmetric magnetization signal is converted to detectable voltage signals;
Direct current signal processing unit, it is connected with described direct current signal detecting unit, to receive and to carry out respective handling to described detectable voltage signals, and exports corresponding direct current processing signals;
Restoring circuit unit, it is connected with described direct current signal detecting unit, to receive and described detectable voltage signals to be compared with a preset voltage value, and exports the oscillator signal that demagnetizes accordingly;
AC signal processing unit, it is connected with described ancillary coil, with when described primary coil receives described tested alternating current, receives the corresponding sensor current signal that described ancillary coil exports, and respective handling is carried out to this sensor current signal, exchange processing signals accordingly to export; And
Power amplification unit, its input end respectively with described direct current signal processing unit, restoring circuit unit and AC signal processing unit connect, its output terminal is connected with described secondary coil, thus receive described direct current processing signals, and export a direct current offset current to described secondary coil, and receive described demagnetization oscillator signal, one is exported for making the demagnetization current of described second magnetic core demagnetization to described secondary coil, or receive described interchange processing signals, and export an AC compensation electric current to described secondary coil, wherein, described DC compensation electric current and its size of current contrary with the direction of described measured DC be the Np/Ns of this measured DC doubly, the Np/Ns of described AC compensation electric current and its size of current contrary with the direction of described tested alternating current tested alternating current that is this doubly.
In above-mentioned alterating and direct current flow sensor, the number of turn of described first field coil and the number of turn of described second field coil identical or different.
In above-mentioned alterating and direct current flow sensor, described pumping signal generating unit is connected with the different name end of described first field coil, and is connected with the Same Name of Ends of described second field coil.
In above-mentioned alterating and direct current flow sensor, described pumping signal generating unit is connected with the Same Name of Ends of described first field coil, and is connected with the different name end of described second field coil.
In above-mentioned alterating and direct current flow sensor, described pumping signal generating unit comprises the signal source and a signal amplifier that connect successively, and wherein, described signal amplifier is connected with described first field coil and described second field coil.
In above-mentioned alterating and direct current flow sensor, described direct current signal detecting unit comprises: phased door, its input end receives the phased signal of described asymmetric magnetization signal and a peripheral input, its output terminal is successively by the first resistance and the first capacity earth, wherein, described first resistance exports described detectable voltage signals with the end that is connected of the first electric capacity.
In above-mentioned alterating and direct current flow sensor, described direct current signal processing unit comprises: the first operational amplifier, its positive input terminal receives described detectable voltage signals by the 3rd resistance and the second resistance successively, its output terminal exports described direct current processing signals, and according to this by the 5th resistance and the 4th resistance eutral grounding, its negative input end is connected between described 4th resistance and the 5th resistance, and wherein, the end that is connected of described 3rd resistance and the second resistance is by the second capacity earth.
In above-mentioned alterating and direct current flow sensor, described direct current signal detecting unit comprises: the first diode and the second diode, wherein, the positive pole of described first diode is connected with the negative pole of the second diode to receive described asymmetric magnetization signal, the negative pole of described first diode is by the 3rd capacity earth, be connected with the 6th resistance simultaneously, the positive pole of described second diode is by the 4th capacity earth, be connected with the 7th resistance, and described 6th resistance is connected to export described detectable voltage signals with the 7th resistance simultaneously.
In above-mentioned alterating and direct current flow sensor, described direct current signal processing unit comprises: the second operational amplifier, its positive input terminal is by the 8th resistance eutral grounding, its negative input end receives described detectable voltage signals by the 9th resistance, its output terminal exports described direct current processing signals, and be connected between the negative input end of this second operational amplifier and described 9th resistance by the tenth resistance, wherein, described tenth resistance two ends are parallel with the 5th electric capacity.
In above-mentioned alterating and direct current flow sensor, described AC signal processing unit comprises: the 3rd operational amplifier, its positive input terminal is by the 11 resistance eutral grounding, its negative input end receives described sensor current signal by the 12 resistance, its output terminal exports described interchange processing signals, wherein, described 12 resistance passes through the 13 resistance and the 6th capacity earth successively with the end that is connected of the negative input end of the 3rd operational amplifier, is parallel with the 14 resistance between the negative input end of described 3rd operational amplifier and output terminal.
In above-mentioned alterating and direct current flow sensor, described restoring circuit unit comprises: the signal comparison module connected successively, multiple-harmonic oscillator and signal driver, wherein, described signal comparison module receives described detectable voltage signals, and described signal driver exports described demagnetization oscillator signal.
In above-mentioned alterating and direct current flow sensor, described power amplification unit comprises: four-operational amplifier, its positive input terminal is by the 15 resistance eutral grounding, its negative input end is received described interchange processing signals respectively by the 16 resistance, is received described direct current processing signals and receive described demagnetization oscillator signal by the 18 resistance by the 17 resistance, its output terminal is connected with described secondary coil, wherein, the 7th electric capacity and the 19 resistance that connect successively is parallel with between the negative input end of described four-operational amplifier and output terminal.
In above-mentioned alterating and direct current flow sensor, described first magnetic core, the second magnetic core and the 3rd magnetic core are made by high permeability material.
Owing to have employed above-mentioned technical solution, the utility model has the following advantages:
1, the utility model is by regulating the exciting current of first, second field coil of input, to relax on the basis to the requirement of each magnetic core parameter (such as, initial permeability, maximum permeability, magnetic core consistance etc.), the testing current quality of energy excellent equally;
2, the utility model carrys out driving power amplifying unit by direct current signal processing unit or AC signal processing unit and realizes profound and negative feedbck, thus reduce proportional error, nonlinearity erron from principle, improve current detection accuracy, expand current detection range;
3, the utility model is by adopting AC signal processing unit, when the first magnetic core, the second magnetic core are identical with the 3rd magnetic core gross section, improve the linear work district of core flux density, has significant contribution to the miniaturization of product;
4, the utility model suitably regulates the exciting current of first, second field coil of input by pumping signal generating unit, can eliminate the impact of exciting current on the output signal of secondary coil, thus reduces output noise; Meanwhile, because direct current or AC signal processing unit have compensating action, therefore can according to actual needs flexible compensating parameter to reach desirable, and do not need adopt inductance filtering is carried out to output signal;
5, the utility model is by adopting the magnetic core made of high magnetic conductance material as magnetic balance element, thus can avoid the interference of extraneous magnetic field, improves the reliability of current detecting;
6, whole circuit of the present utility model is suitable for device and is general-purpose device, is therefore convenient to realize, and in the utility model circuit and magnetic circuit separated, thus can to replace flexibly.
7, (namely required in the utility model current measurement value exports with current system, what secondary coil exported is the DC current or alternating current that record), therefore, can be convenient to be transformed to magnitude of voltage (such as realizing conversion by a resistance of connecting at the output terminal of secondary coil) according to actual needs.
In a word, the utility model significantly improves performance (such as, the long-time stability: < 2ppm/24h of sensor; Precision (linearity): < 10ppm; Temperature coefficient < 0.7ppm/ DEG C; Wide-range: 0.1mA-3kA), and have that low in energy consumption, diamagnetic interference performance is strong, structure is simple, lightweight, fast response time, highly sensitive, interchangeability good and install, calibration, debugging, safeguard the advantages such as all very convenient.
Accompanying drawing explanation
Fig. 1 is the theory diagram of a kind of alterating and direct current flow sensor of the utility model;
Fig. 2 is a kind of circuit structure diagram of direct current signal detecting unit in the utility model;
Fig. 3 is a kind of circuit structure diagram of direct current signal processing unit in the utility model;
Fig. 4 is the another kind of circuit structure diagram of direct current signal detecting unit in the utility model;
Fig. 5 is the another kind of circuit structure diagram of direct current signal processing unit in the utility model;
Fig. 6 is the circuit structure diagram of AC signal processing unit in the utility model;
Fig. 7 is the theory diagram of restoring circuit unit in the utility model;
Fig. 8 is the circuit structure diagram of restoring circuit unit in the utility model;
Fig. 9 is the circuit structure diagram of power amplification unit in the utility model;
Figure 10 is waveform Cleaning Principle figure in the utility model.
Embodiment
Below in conjunction with accompanying drawing, provide preferred embodiment of the present utility model, and be described in detail.
As shown in Figure 1, the utility model, that is, a kind of alterating and direct current flow sensor, comprising:
High magnetic conduction transformer unit T, it comprises:
First magnetic core independent of each other and the second magnetic core;
Be wound on the first field coil L1 on the first magnetic core and the second magnetic core and the second field coil L2 respectively, wherein, the number of turn of the first field coil L1 is n1, and the number of turn of the second field coil L2 is n2, and n1 can be identical with n2, also can be different;
3rd magnetic core, itself and the first magnetic core and the second magnetic core stack together, and to form a whole magnetic core, wherein, first, second, and third magnetic core is made by high permeability material; And
Be wound on the primary coil L3 on whole magnetic core, secondary coil L4 and ancillary coil L5, wherein, the number of turn of primary coil L3 is Np, and this primary coil L3 receives the measured DC of peripheral input or tested alternating current (i), the number of turn of secondary coil L4 is Ns, and secondary coil L4 exports the DC current or alternating current (Output) that record, the number of turn of ancillary coil L5 is N;
Pumping signal generating unit 1, it is connected with the first field coil L1 and the second field coil L2, to provide the exciting current of two phase differential 180 ° respectively to the first field coil L1 and the second field coil L2;
Direct current signal detecting unit 2, it is connected with the second field coil L2, with when primary coil L3 receives measured DC, receives the corresponding asymmetric magnetization signal that the second field coil L2 exports, and this asymmetric magnetization signal is converted to detectable voltage signals;
Direct current signal processing unit 3, it is connected with direct current signal detecting unit 2, to receive and to carry out respective handling to detectable voltage signals, and exports corresponding direct current processing signals;
Restoring circuit unit 4, it is connected with direct current signal detecting unit 2, to receive and detectable voltage signals to be compared with a preset voltage value, and exports the oscillator signal that demagnetizes accordingly;
AC signal processing unit 5, it is connected with ancillary coil L5, with when primary coil L3 receives tested alternating current, receives the corresponding sensor current signal that ancillary coil L5 exports, and respective handling is carried out to this sensor current signal, exchange processing signals accordingly to export; And
Power amplification unit 6, its input end respectively with direct current signal processing unit 3, restoring circuit unit 4 and AC signal processing unit 5 connect, its output terminal is connected with secondary coil L4, thus receive direct current processing signals, and export a direct current offset current to secondary coil L4, and receive demagnetization oscillator signal, one is exported for making the demagnetization current of the second magnetic core demagnetization to secondary coil L4, or receive and exchange processing signals, and export an AC compensation electric current to secondary coil L4, wherein, DC compensation electric current and its size of current contrary with the direction of measured DC be the Np/Ns of this measured DC doubly, the Np/Ns of AC compensation electric current and its size of current contrary with the direction of tested alternating current tested alternating current that is this doubly.
As shown in Figure 1, in the present embodiment, pumping signal generating unit 1 is connected with the different name end of the first field coil L1, and is connected with the Same Name of Ends of the second field coil L2.But pumping signal generating unit 1 also can be connected with the Same Name of Ends of the first field coil L1, and is connected with the different name end of the second field coil L2.Pumping signal generating unit 1 in the present embodiment comprises the signal source 11 and signal amplifier 12 that connect successively, wherein, signal source 11 refers to general signal generating circuit, its signal produced comprises: without the signal such as AC sine wave, square wave, triangular wave, sawtooth wave, trapezoidal wave of direct current biasing, signal amplifier 12 is connected with the first field coil L1 and the second field coil L2.
As shown in Figure 2, a kind of embodiment (namely adopting phase frequency detection principle) of the direct current signal detecting unit 2 in the utility model comprises: phased door 21, its input end receives the asymmetric magnetization signal of the second field coil L2 output and the phased signal of peripheral input, its output terminal is successively by the first resistance R1 and the first electric capacity C1 ground connection, wherein, the first resistance R1 and the end that is connected of the first electric capacity C1 are to direct current signal processing unit 3 output detections voltage signal.The principle of work with the direct current signal detecting unit 2 of said structure is: by selecting the break-make of phased gate control phased signal, therefrom detect tested current signal, phased signal selects 4 frequencys multiplication of excitation frequency, control asymmetric magnetization signal by phased signal to charge to the first electric capacity C1 via the first resistance R1 respectively in positive-negative half-cycle, after a tested signal period, it is exactly detectable voltage signals that the voltage on the first electric capacity C1 is.
As shown in Figure 3, for the direct current signal detecting unit 2 adopting phase frequency detection principle, a kind of embodiment of the direct current signal processing unit 3 in the utility model comprises: the first operational amplifier 31, its positive input terminal receives detectable voltage signals by the 3rd resistance R3 and the second resistance R2 successively, its output terminal exports direct current processing signals to power amplification unit 6, and according to this by the 5th resistance R5 and the 4th resistance R4 ground connection, its negative input end is connected between the 4th resistance R4 and the 5th resistance R5, wherein, the end that is connected of the 3rd resistance R3 and the second resistance R2 is by the second electric capacity C2 ground connection.In above-mentioned direct current signal processing unit 3, with the first operational amplifier 31 for core, second, third resistance R2, R3 and the second electric capacity C2 realizes filtering, and the 4th, the 5th resistance R4, R5 realizes gain, finally realizes direct current signal process.
As shown in Figure 4, the another kind of embodiment (namely adopting peak detection principle) of the direct current signal detecting unit 2 in the utility model comprises: the first diode D1, its positive pole receives the asymmetric magnetization signal that the second field coil L2 exports, its negative pole, by the 3rd electric capacity C3 ground connection, passes through the 6th resistance R6 to direct current signal processing unit 3 output detections voltage signal simultaneously; And the second diode D2, its negative pole receives the asymmetric magnetization signal that the second field coil L2 exports, its positive pole is by the 4th electric capacity C4 ground connection, pass through the 7th resistance R7 to direct current signal processing unit 3 output detections voltage signal simultaneously, wherein, the positive pole of the first diode D1 is connected to accept asymmetric magnetization signal with the negative pole of the second diode D2, and the 6th resistance R6 is connected with the 7th resistance R7 with output detections voltage signal.In above-mentioned direct current signal detecting unit 2, the resistance of the 6th resistance R6 and the 7th resistance R7 is larger, 6th resistance R6, 3rd electric capacity C3 and the 7th resistance R7, the time constant of the 4th electric capacity C4 is far longer than the cycle of asymmetric magnetization signal, the first diode D1 conducting when asymmetric magnetization signal is positive peak, thus charge to the 3rd electric capacity C3, when being negative peak by asymmetric magnetization signal, second diode D2 conducting, thus charge to the 4th electric capacity C4, after the one-period of asymmetric magnetization signal, 3rd, 4th electric capacity C3, C4 reaches respective maximal value, by the 6th, 7th resistance R6, R7 does additive operation, obtain detectable voltage signals.
As shown in Figure 5, for the direct current signal detecting unit 2 adopting peak detection principle, the another kind of embodiment of the direct current signal processing unit 3 in the utility model comprises: the second operational amplifier 32, its positive input terminal is by the 8th resistance R8 ground connection, its negative input end receives detectable voltage signals by the 9th resistance R9, its output terminal exports direct current processing signals to power amplification unit 6, and be connected between the negative input end of this second operational amplifier 32 and the 9th resistance R9 by the tenth resistance R10, wherein, the tenth resistance R10 two ends are parallel with the 5th electric capacity C5.In above-mentioned direct current signal processing unit 3, with the second operational amplifier 32 for core, nine, the tenth resistance R9, R10 and the 5th electric capacity C5 jointly realizes signal filtering and improves gain, thus completing AC signal process, the 8th resistance R8 completes the signal input grounding of the second operational amplifier 32.
As shown in Figure 6, AC signal processing unit 5 in the utility model comprises: the 3rd operational amplifier 51, its positive input terminal is by the 11 resistance R11 ground connection, its negative input end receives the sensor current signal of ancillary coil L5 output by the 12 resistance R12, its output terminal is to power amplification unit 6 output AC processing signals, wherein, 12 resistance R12 passes through the 13 resistance R13 and the 6th electric capacity C6 ground connection successively with the end that is connected of the negative input end of the 3rd operational amplifier 51, the 14 resistance R14 is parallel with between the negative input end of the 3rd operational amplifier 51 and output terminal.
As shown in Figure 7, restoring circuit unit 4 in the utility model comprises: the signal comparison module 41 connected successively, multiple-harmonic oscillator 42 and signal driver 43, wherein, signal comparison module 41 receives the detectable voltage signals that direct current signal detecting unit 2 exports, and signal driver 43 exports demagnetization oscillator signal to power amplification unit 6.Illustrated in the present embodiment in Fig. 8, the particular circuit configurations of signal comparison module 41, multiple-harmonic oscillator 42 and signal driver 43, such as, signal comparison module 41 comprises: comparer 411, the 20,21 resistance R20, R21 and the 8th electric capacity C8; Multiple-harmonic oscillator 42 comprises: timer the 421, the 20th the two to two 14 resistance R22-R24 and the 9th electric capacity C9; Signal driver 43 comprises: triode Q1 and the 20th the five to two 17 resistance R25-R27 (because above-mentioned signal comparison module 41, multiple-harmonic oscillator 42 and signal driver 43 are this area conventional device, therefore its structure repeats no more herein).
As shown in Figure 9, power amplification unit 6 in the utility model comprises: four-operational amplifier 61, its positive input terminal is by the 15 resistance R15 ground connection, its negative input end is received respectively by the 16 resistance R16 and exchanges processing signals, received direct current processing signals by the 17 resistance R17 and receive demagnetization oscillator signal by the 18 resistance R18, its output terminal is connected with secondary coil L4, wherein, the 7th electric capacity C7 and the 19 resistance R19 that connect successively is parallel with between the negative input end of four-operational amplifier 61 and output terminal.In above-mentioned power amplification unit 6, negative feedback constant gain loop is formed with the 7th electric capacity C7 and the 19 resistance R19 and the 16 to the 18 resistance R16-R18, realize power steadily to export, the 15 resistance R15 completes the input signal ground connection of four-operational amplifier 61.Power amplification unit 6 receives the signal that direct current or AC signal processing unit 3 or 5 and restoring circuit unit 4 provide, and makes the electric current of the current canceling primary coil L3 of secondary coil L4, realizes the accurate Zero flux of magnetic core (concrete principle describes hereinafter).
Principle of work of the present utility model is as follows:
In the utility model, first, second field coil L1, L2 coordinate the links such as pumping signal, input, signal transacting and power amplification to complete the current measurement of DC-tens Hz.Specifically, the difference end of first, second field coil L1, L2 is connected with pumping signal generating unit 1 respectively, therefore the magnetic flux produced in these two inductance is for secondary coil L4, amplitude is equal, direction is contrary, thus eliminate pumping signal to the impact of measuring numerical value, reduce the background noise of measurement.
For convenience of describing, here for the second field coil L2, suppose simultaneously pumping signal that pumping signal generating unit 1 exports be square wave so that measuring process to be described: the exciting current waveform in the second field coil L2 see can Figure 10, using this exciting current signal as carrier wave.When tested electric current is zero, the signal integration that detection detects is zero, when tested electric current is non-vanishing, the signal integration that detection detects is non-vanishing, this non-vanishing signal gives power amplification unit 6, thus the electric current identical with primary coil L3 ampere-turn is produced on secondary coil L4, make the magnetization current waveform symmetry on the second field coil L2, and then detection is detected is zero; When there being alternating current in primary coil L3, ancillary coil L5 senses the current signal of primary coil L3, this signal is delivered to power amplification unit 6, thus make secondary coil L4 to produce Np/Ns times that the electric current contrary with primary coil L3 electric current and amplitude are tested electric current, and then complete ac current measurement (to 100kHz).
Restoring circuit unit 4 can ensure that whole feedback is in controllable state, specifically, when booting moment or primary coil L3 have overcurrent etc. to impact, will destroy the negative feedback duty of whole circuit.Under normal circumstances, the the second field coil L2 be made up of high permeability material is operated in and is easy to enter state of saturation close to saturated region under the effect of pumping signal, when strong jamming destroys negative feedback, circuit enters positive feedback, power amplification unit 6 exports the maximum voltage value of plus or minus, and cause secondary coil L4 to export the maximum current of plus or minus, the magnetic core of the second field coil L2 enters state of saturation, even if undesired signal is removed, the magnetic core of L2 can not automatically return to the state before interference.Therefore, the circuit of detection second field coil L2 magnetic core duty is devised specially in the utility model, when the magnetic core of the second field coil L2 is saturated, second field coil L2 loses inductance effectiveness, the asymmetric magnetization signal that direct current signal detecting unit 2 detects exceedes setting value, multiple-harmonic oscillator in restoring circuit unit 4, produce the square wave far below exciting signal frequency, and send into power amplification unit 6 through signal driver, the signal subtraction sent here of this signal and direct current signal processing unit 3 is as the input of power amplification unit 6, when above-mentioned two signal subtractions are zero, power amplification unit 6 exports no-voltage, the magnetic core of the second field coil L2 exits state of saturation, whole circuit enters negative feedback state again, when the signal that direct current signal detecting unit 2 detects is lower than setting value, then restoring circuit unit 4 quits work, rejuvenation terminates, complete magnetic core magnetic bias to correct.
Based on above-mentioned principle, when there is DC magnetic biasing in magnetic core, ac-excited signal is first, second field coil L1, electric current on L2 just there will be the asymmetric distorted waveform of positive and negative half-wave, direct current signal detecting unit 2 obtains the asymmetric situation of exciting current signal, coating-forming voltage signal after positive and negative for this asymmetric waveform half wave conversion is delivered to direct current signal processing unit 3, treated signal promotes power amplification unit 6 and produces and the reciprocal Ns/Np of measured DC electric current doubly, to balance the magnetic bias magnetic potential that measured DC produces, thus form " accurate Zero flux state ", and then realize the Detection task of DC current.
In like manner, when tested electric current is alternating current, form alternating current biasing in magnetic core, ancillary coil L5, primary coil L3, secondary coil L4 and power amplification unit 6 complete ac current measurement jointly.
When magnetic core state departs from accurate Zero flux state, the electric current of ac-excited signal on first, second field coil L1, L2 just there will be the asymmetric limit distorted waveform of positive and negative half-wave, when direct current signal testing circuit obtains maximum asymmetric magnetization signal, then start restoring circuit unit 4, AC demagnetization is carried out to magnetic core, makes magnetic core come back to the controllable state of accurate Zero flux.
In other words, in the utility model, alternating message source magnetizes first, second field coil L1, L2, in outside during tested current i=0, first, second field coil L1, L2 phase-inversion symmetric magnetizes, the magnetization signal both forward and reverse directions amplitude equal direction exported is contrary, and the asymmetric magnetization signal that direct current signal detecting unit 2 detects is zero, and direct current signal processing unit 3 and power amplification unit 6 all export with zero-signal.
When DC current i ≠ 0, second magnetic core of the second field coil L2 is magnetized, the magnetization of pumping signal on the second field coil L2 just occurs asymmetric, this asymmetric magnetization signal is directly proportional or inverse ratio to tested electric current, after direct current signal detecting unit 2 detects this asymmetric magnetization signal, deliver to direct current signal processing unit 3 by a certain percentage, after signal transacting, promote power amplification unit 6 produces contrary with tested direction of current, and amplitude is tested electric current Np/Ns electric current doubly, thus produce the rightabout direct current magnetic potential of magnetic potential produced with tested direct current, to balance the magnetic bias magnetic potential that tested direct current produces, and then the magnetic flux in magnetic core is close to zero, complete the Zero flux magnetic balance in popular saying, therefore tested direct current size can be obtained, thus realize the Detection task of DC current.
When alternating current i ≠ 0, power amplification unit 6 is voltage source, and primary coil L3 and secondary coil L4 relies on the 3rd magnetic core to complete transformer current conversion, realizes the magnetic balance of magnetic core Zero flux, is mutual inductor, thus realize the Detection task of alternating current.
The asymmetric magnetization signal that restoring circuit unit 4 is delivered to by comparing direct current signal detecting unit 2, judge that whether normal the magnetized state of the second magnetic core is, when the magnetization of the second magnetic core has exceeded setting value, restoring circuit unit 4 starts demagnetization oscillator signal, and promotion power amplification unit 6 produces big current and completes demagnetization process; After demagnetization terminates, demagnetization oscillator signal stops, and integrated circuit completes profound and negative feedbck by direct current signal processing unit 3 according to detectable voltage signals driving power amplifying unit 6.
In sum, ingehious design of the present utility model, make tested electric current be direct current or exchange time, automatically switch, automatically complete current measurement; The utility model is suitable for detecting 0Hz-100kHz electric current, such as, be applied to: the ac and dc current input of the industries such as the current feedback of power electronic equipment, control of damming, high-accuracy steady-flow adjustment, over-current detection, accelerator magnet power supply, electric system and electrolysis.
Above-described, be only preferred embodiment of the present utility model, and be not used to limit scope of the present utility model, above-described embodiment of the present utility model can also make a variety of changes.Namely every claims according to the utility model application and description are done simple, equivalence change and modify, and all fall into the claims of the utility model patent.The not detailed description of the utility model be routine techniques content.
Claims (13)
1. an alterating and direct current flow sensor, is characterized in that, described sensor comprises:
High magnetic conduction transformer unit, it comprises:
First magnetic core independent of each other and the second magnetic core;
Be wound on the first field coil on described first magnetic core and the second magnetic core and the second field coil respectively;
3rd magnetic core, itself and described first magnetic core and the second magnetic core stack together, to form a whole magnetic core; And
Be wound on the primary coil on described whole magnetic core, secondary coil and ancillary coil, wherein, the number of turn of described primary coil is Np, and described primary coil receives the measured DC of peripheral input or tested alternating current, the number of turn of described secondary coil is Ns, and described secondary coil exports the DC current or alternating current that record;
Pumping signal generating unit, it is connected with described first field coil and described second field coil, to provide the exciting current of two phase differential 180 ° respectively to described first field coil and the second field coil;
Direct current signal detecting unit, it is connected with described second field coil, with when described primary coil receives described measured DC, receive the corresponding asymmetric magnetization signal that described second field coil exports, and this asymmetric magnetization signal is converted to detectable voltage signals;
Direct current signal processing unit, it is connected with described direct current signal detecting unit, to receive and to carry out respective handling to described detectable voltage signals, and exports corresponding direct current processing signals;
Restoring circuit unit, it is connected with described direct current signal detecting unit, to receive and described detectable voltage signals to be compared with a preset voltage value, and exports the oscillator signal that demagnetizes accordingly;
AC signal processing unit, it is connected with described ancillary coil, with when described primary coil receives described tested alternating current, receives the corresponding sensor current signal that described ancillary coil exports, and respective handling is carried out to this sensor current signal, exchange processing signals accordingly to export; And
Power amplification unit, its input end respectively with described direct current signal processing unit, restoring circuit unit and AC signal processing unit connect, its output terminal is connected with described secondary coil, thus receive described direct current processing signals, and export a direct current offset current to described secondary coil, and receive described demagnetization oscillator signal, one is exported for making the demagnetization current of described second magnetic core demagnetization to described secondary coil, or receive described interchange processing signals, and export an AC compensation electric current to described secondary coil, wherein, described DC compensation electric current and its size of current contrary with the direction of described measured DC be the Np/Ns of this measured DC doubly, the Np/Ns of described AC compensation electric current and its size of current contrary with the direction of described tested alternating current tested alternating current that is this doubly.
2. alterating and direct current flow sensor according to claim 1, is characterized in that, the number of turn of described first field coil and the number of turn of described second field coil identical or different.
3. alterating and direct current flow sensor according to claim 1, is characterized in that, described pumping signal generating unit is connected with the different name end of described first field coil, and is connected with the Same Name of Ends of described second field coil.
4. alterating and direct current flow sensor according to claim 1, is characterized in that, described pumping signal generating unit is connected with the Same Name of Ends of described first field coil, and is connected with the different name end of described second field coil.
5. the alterating and direct current flow sensor according to claim 1,3 or 4, it is characterized in that, described pumping signal generating unit comprises the signal source and a signal amplifier that connect successively, and wherein, described signal amplifier is connected with described first field coil and described second field coil.
6. alterating and direct current flow sensor according to claim 1, it is characterized in that, described direct current signal detecting unit comprises: phased door, its input end receives the phased signal of described asymmetric magnetization signal and a peripheral input, its output terminal is successively by the first resistance and the first capacity earth, wherein, described first resistance exports described detectable voltage signals with the end that is connected of the first electric capacity.
7. alterating and direct current flow sensor according to claim 6, it is characterized in that, described direct current signal processing unit comprises: the first operational amplifier, its positive input terminal receives described detectable voltage signals by the 3rd resistance and the second resistance successively, its output terminal exports described direct current processing signals, and according to this by the 5th resistance and the 4th resistance eutral grounding, its negative input end is connected between described 4th resistance and the 5th resistance, wherein, described 3rd resistance and the end that is connected of the second resistance are by the second capacity earth.
8. alterating and direct current flow sensor according to claim 1, it is characterized in that, described direct current signal detecting unit comprises: the first diode and the second diode, wherein, the positive pole of described first diode is connected with the negative pole of the second diode to receive described asymmetric magnetization signal, the negative pole of described first diode is by the 3rd capacity earth, be connected with the 6th resistance simultaneously, the positive pole of described second diode is by the 4th capacity earth, be connected with the 7th resistance, and described 6th resistance is connected to export described detectable voltage signals with the 7th resistance simultaneously.
9. alterating and direct current flow sensor according to claim 8, it is characterized in that, described direct current signal processing unit comprises: the second operational amplifier, its positive input terminal is by the 8th resistance eutral grounding, its negative input end receives described detectable voltage signals by the 9th resistance, and its output terminal exports described direct current processing signals, and is connected between the negative input end of this second operational amplifier and described 9th resistance by the tenth resistance, wherein, described tenth resistance two ends are parallel with the 5th electric capacity.
10. alterating and direct current flow sensor according to claim 1, it is characterized in that, described AC signal processing unit comprises: the 3rd operational amplifier, its positive input terminal is by the 11 resistance eutral grounding, its negative input end receives described sensor current signal by the 12 resistance, its output terminal exports described interchange processing signals, wherein, described 12 resistance passes through the 13 resistance and the 6th capacity earth successively with the end that is connected of the negative input end of the 3rd operational amplifier, is parallel with the 14 resistance between the negative input end of described 3rd operational amplifier and output terminal.
11. alterating and direct current flow sensor according to claim 1, it is characterized in that, described restoring circuit unit comprises: the signal comparison module connected successively, multiple-harmonic oscillator and signal driver, wherein, described signal comparison module receives described detectable voltage signals, and described signal driver exports described demagnetization oscillator signal.
12. alterating and direct current flow sensor according to claim 1, it is characterized in that, described power amplification unit comprises: four-operational amplifier, its positive input terminal is by the 15 resistance eutral grounding, its negative input end receives described interchange processing signals respectively by the 16 resistance, receive described direct current processing signals by the 17 resistance and receive described demagnetization oscillator signal by the 18 resistance, its output terminal is connected with described secondary coil, wherein, the 7th electric capacity and the 19 resistance that connect successively is parallel with between the negative input end of described four-operational amplifier and output terminal.
13. alterating and direct current flow sensor according to claim 1, is characterized in that, described first magnetic core, the second magnetic core and the 3rd magnetic core are made by high permeability material.
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| CN201420413079.6U CN204044224U (en) | 2014-07-24 | 2014-07-24 | A kind of alterating and direct current flow sensor |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104090146B (en) * | 2014-07-24 | 2017-01-18 | 中国科学院上海应用物理研究所 | Alternating current/direct current sensor |
| CN107817373A (en) * | 2016-09-14 | 2018-03-20 | 台达电子工业股份有限公司 | Current sensing means and its detection method |
| CN111693753A (en) * | 2019-11-29 | 2020-09-22 | 中国计量大学 | Novel direct current measuring device |
| CN111948438A (en) * | 2020-08-18 | 2020-11-17 | 宁波中车时代传感技术有限公司 | Low-cost current sensor |
-
2014
- 2014-07-24 CN CN201420413079.6U patent/CN204044224U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104090146B (en) * | 2014-07-24 | 2017-01-18 | 中国科学院上海应用物理研究所 | Alternating current/direct current sensor |
| CN107817373A (en) * | 2016-09-14 | 2018-03-20 | 台达电子工业股份有限公司 | Current sensing means and its detection method |
| CN111693753A (en) * | 2019-11-29 | 2020-09-22 | 中国计量大学 | Novel direct current measuring device |
| CN111948438A (en) * | 2020-08-18 | 2020-11-17 | 宁波中车时代传感技术有限公司 | Low-cost current sensor |
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