CN104090146B - Alternating current/direct current sensor - Google Patents
Alternating current/direct current sensor Download PDFInfo
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- CN104090146B CN104090146B CN201410355923.9A CN201410355923A CN104090146B CN 104090146 B CN104090146 B CN 104090146B CN 201410355923 A CN201410355923 A CN 201410355923A CN 104090146 B CN104090146 B CN 104090146B
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Abstract
The invention relates to an alternating current/direct current sensor. The alternating current/direct current sensor comprises a high-permeability transformer unit, an excitation signal generation unit, a direct current signal detection unit, a restoring circuit unit, an alternating current signal processing unit and a power amplification unit. The high-permeability transformer unit comprises a first magnetic core, a second magnetic core, a first magnet exciting coil, a second magnet exciting coil, a third magnetic core, a primary coil, a secondary coil and an auxiliary coil, wherein the first magnetic core and the second magnetic core are independent of each other; the first magnet exciting coil and the second magnet exciting coil are wound around the first magnetic core and the second magnetic core respectively; the third magnetic core, the first magnetic core and the second magnetic core are overlapped so as to form an integrated magnetic core; the primary coil, the secondary coil and the auxiliary coil are wound around the integrated magnetic core. The performance of the alternating current/direct current sensor is improved remarkably. The alternating current/direct current sensor has the advantages of being low in power dissipation, high in magnetic disturbance resistance capacity, simple in structure, light, high in response speed, high in flexibility, good in interchangeability, convenient to install, calibrate, adjust and maintain, and the like.
Description
Technical field
The present invention relates to a kind of alterating and direct current flow sensor.
Background technology
In DC transmission system, RHVC, ups power supply, inverter type welder, electrolysis plating, Digit Control Machine Tool, microcomputer prison
In examining system, accelerator operation, grid monitoring system and the every field needing isolation detection electric current, accurate detection and control are straight
Stream electric current, is the basic assurance of equipment safety reliability service and the problem first having to solve.
The means being presently used for measuring electric current include: current comparator, D.C mutual-inductor, direct current instrument transformer, current divider etc.
Current measuring method and equipment, the equipment of above different size all can commercially find.But with above-mentioned current measuring method it is
The equipment on basis is often due to method itself or use occasion condition, cost limit, and the current measurement in high accuracy, wide scope
Aspect shows many deficiencies；For example: current comparator is to the frequency limit of tested electric current in 50hz；Transformer is to tested electricity
Stream AC and DC composition has restriction；Current divider has that high current heating is serious and does not isolate.As can be seen here, above-mentioned
The method and apparatus of several measurement electric currents limits its certainty of measurement, measurement noise level etc., in other words, in height in principle
Precision, wide scope current measurement aspect, the said equipment apparently not competent measurement request.
Meanwhile, have also appeared some in prior art based on the physical effect such as magneto-optic effect and nuclear magnetic resonance
The measurement equipment of electric current and method, wherein, magneto-optic effect measure electric current equipment can on the south Swiss Airways sky the full light of nae-gl series
As a example fiber electronic current transformer, but magneto-optic effect surveys current limited in the birefringence effect of magneto-optic glass, therefore both drops
Low certainty of measurement increased equipment cost again, and expensive price makes it apply and is confined to power transmission and transformation industry.And with nuclear magnetic resonance
Based on measurement current methods be only used for measure absolute ampere when laboratory method or measurement criteria, therefore not by
Large-scale industrial production is adopted.
Comparatively speaking, dielectric strength is high, it is reliable, cheap etc. excellent to operate because it has for transformer type current transformer
Point, is extensively widely used in social production practice.The general principle of transformer type current transformer is: when excitatory ampere-turn is
When zero, the change of secondary ampere-turn can reflect that former limit ampere-turn changes completely, and error is zero, and magnetic core now is in " quasi- Zero flux " shape
State, it works in the initial segment (i.e. linearity range) of magnetization curve, and at this moment, current transformer output would not be distorted by shape, can protect
Hold the good linearity, be commonly called as " Zero flux " principle.Therefore, if transformer core can be made to be in Zero flux state all the time, with regard to energy
It is inherently eliminated the error of current transformer.But, from the operation principle of transformer, rely on transformer itself to be can not
Enable Zero flux it is necessary to the compensation by external condition or adjustment.
For this reason, occur in that magnetic amplifier comparator (hereinafter referred to as magnetic amplifier) and magnetic modulator compare in prior art again
Instrument (hereinafter referred to as magnetic modulator), they all carry out current measurement using " Zero flux state " principle.However, magnetic amplifier due to
Its complex structure, heaviness, thus limit the application of its miniaturization and high-acruracy survey.And common magnetic modulator includes single magnetic
Core and two kinds of bimag, traditional magnetic modulation current detecting requires two magnetic cores must have identical physical dimension and completely the same
Magnetic characteristic, and easily false equalization point in the open loop characteristic curve of magnetic modulator, thus reduce magnetic modulator running
Reliability, therefore, limit application and the popularization of magnetic modulator.
Content of the invention
In order to solve the problems, such as above-mentioned prior art, the present invention is intended to provide a kind of alternating current-direct current of high accuracy Magnetic isolation
Current sensor, to form " quasi- Zero flux state ", thus realize the accurate detection of electric current.
A kind of alterating and direct current flow sensor of the present invention, comprising:
High magnetic conduction transformer unit, comprising:
First magnetic core independent of each other and the second magnetic core；
It is wound on the first magnet exciting coil on described first magnetic core and the second magnetic core and the second magnet exciting coil respectively；
3rd magnetic core, it is stacked together with described first magnetic core and the second magnetic core, to form a whole magnetic core；And
It is wound on primary coil on described whole magnetic core, secondary coil and ancillary coil, wherein, described primary coil
The number of turn is np, and described primary coil receives the measured DC of periphery input or tested alternating current, described secondary coil
The number of turn be ns, and the described secondary coil DC current that records of output or alternating current；
Pumping signal generating unit, it is connected with described first magnet exciting coil and described second magnet exciting coil, with respectively
The exciting current of 180 ° of two phase differences is provided to described first magnet exciting coil and the second magnet exciting coil；
Direct current signal detector unit, it is connected with described second magnet exciting coil, to receive described quilt in described primary coil
When surveying DC current, receive the asymmetric accordingly magnetization signal of described second magnet exciting coil output, and by this asymmetric magnetization
Signal is converted to detectable voltage signals；
Direct current signal processing unit, it is connected with described direct current signal detector unit, with reception and to described detection voltage
Signal carries out respective handling, and exports corresponding direct current process signal；
Restoring circuit unit, it is connected with described direct current signal detector unit, to receive and by described detectable voltage signals
Compare with a preset voltage value, and export corresponding demagnetization oscillator signal；
AC signal processing unit, it is connected with described ancillary coil, with described primary coil receive described by test cross
During stream electric current, receive the corresponding sensor current signal of described ancillary coil output, and this sensor current signal is carried out accordingly
Process, to export corresponding exchange process signal；And
Power amplification unit, its input respectively with described direct current signal processing unit, restoring circuit unit and exchange
Signal processing unit connects, and its output end is connected with described secondary coil, thus receiving described direct current process signal, and to described
Secondary coil exports a DC compensation electric current, and receives described demagnetization oscillator signal, is used for making to described secondary coil output one
The demagnetization current of described second magnetic core demagnetization, or receive described exchange process signal, and to described secondary coil output one friendship
Stream compensates electric current, and wherein, with the in opposite direction of described measured DC and its size of current is described DC compensation electric current
Np/ns times of this measured DC, with the in opposite direction of described tested alternating current and it is electric for described AC compensation electric current
Stream size is np/ns times of this tested alternating current.
In above-mentioned alterating and direct current flow sensor, the number of turn of described first magnet exciting coil and described second magnet exciting coil
The number of turn is identical or different.
In above-mentioned alterating and direct current flow sensor, described pumping signal generating unit is different with described first magnet exciting coil
Name end connects, and is connected with the Same Name of Ends of described second magnet exciting coil.
In above-mentioned alterating and direct current flow sensor, described pumping signal generating unit is same with described first magnet exciting coil
Name end connects, and is connected with the different name end of described second magnet exciting coil.
In above-mentioned alterating and direct current flow sensor, described pumping signal generating unit includes the signal source being sequentially connected
And a signal amplifier, wherein, described signal amplifier and described first magnet exciting coil and described second magnet exciting coil are even
Connect.
In above-mentioned alterating and direct current flow sensor, described direct current signal detector unit includes: phased door, its input termination
Receive described asymmetric magnetization signal and the phased signal of a periphery input, its output end passes sequentially through first resistor and the first electricity
Hold ground connection, wherein, the connected end of described first resistor and the first electric capacity exports described detectable voltage signals.
In above-mentioned alterating and direct current flow sensor, described direct current signal processing unit includes: the first operational amplifier, its
Positive input terminal passes sequentially through 3rd resistor and second resistance receives described detectable voltage signals, and its output end exports at described direct current
Reason signal, and pass through the 5th resistance and the 4th resistance eutral grounding according to this, its negative input end connects to described 4th resistance and the 5th electricity
Between resistance, wherein, the connected end of described 3rd resistor and second resistance passes through the second capacity earth.
In above-mentioned alterating and direct current flow sensor, described direct current signal detector unit includes: the first diode and 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 letter
Number, the negative pole of described first diode passes through the 3rd capacity earth, is connected with the 6th resistance, described second diode is just simultaneously
The 4th capacity earth is passed through in pole, is connected with the 7th resistance simultaneously, and described 6th resistance is connected with the 7th resistance with described in output
Detectable voltage signals.
In above-mentioned alterating and direct current flow sensor, described direct current signal processing unit includes: the second operational amplifier, its
Positive input terminal passes through the 8th resistance eutral grounding, and its negative input end passes through the 9th resistance and receives described detectable voltage signals, its output end
Export described direct current process signal, and connected by the tenth resistance to the negative input end and the described 9th of this second operational amplifier
Between 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 includes: the 3rd operational amplifier, its
Positive input terminal passes through the 11st resistance eutral grounding, and its negative input end passes through the 12nd resistance and receives described sensor current signal, and it is defeated
Go out end and export described exchange process signal, wherein, the phase of described 12nd resistance and the negative input end of the 3rd operational amplifier
Lian Duan passes sequentially through the 13rd resistance and the 6th capacity earth, between the negative input end of described 3rd operational amplifier and output end
It is parallel with the 14th resistance.
In above-mentioned alterating and direct current flow sensor, described restoring circuit unit includes: the signal being sequentially connected compares mould
Block, multi resonant wave oscillator and signal driver, wherein, described signal comparison module receives described detectable voltage signals, described letter
Number driver exports described demagnetization oscillator signal.
In above-mentioned alterating and direct current flow sensor, described power amplification unit includes: four-operational amplifier, it is just defeated
Enter end and pass through the 15th resistance eutral grounding, its negative input end passes through the 16th resistance respectively to be received described exchange process signal, pass through
17th resistance receives described direct current process signal and receives described demagnetization oscillator signal, its output end by the 18th resistance
It is connected with described secondary coil, wherein, be parallel between the negative input end of described four-operational amplifier and output end and connect successively
The 7th electric capacity connecing and the 19th resistance.
In above-mentioned alterating and direct current flow sensor, described first magnetic core, the second magnetic core and the 3rd magnetic core are by high magnetic conduction
Material is made.
Due to employing above-mentioned technical solution, the invention has the advantages that
1st, the present invention passes through to adjust the exciting current of input first, second magnet exciting coil, is relaxing to each magnetic core parameter
Requirement on the basis of (for example, initial permeability, maximum permeability, magnetic core uniformity etc.), equally can excellent
Testing current quality；
2nd, the present invention is realized come driving power amplifying unit by direct current signal processing unit or AC signal processing unit
Profound and negative feedbck, thus reducing proportional error, nonlinearity erron from principle, improve current detection accuracy, expanding electricity
Stream detection range；
3rd, the present invention passes through using AC signal processing unit, in the first magnetic core, the second magnetic core and the 3rd magnetic core total cross section
In the case of identical, improve the linear work area of core flux density, the miniaturization to product has significant contribution；
4th, the present invention passes through the exciting current that pumping signal generating unit suitably adjusts input first, second magnet exciting coil,
The impact of the output signal to secondary coil for the exciting current can be eliminated, thus reducing output noise；Simultaneously as direct current or friendship
Stream signal processing unit there is compensating action, therefore can according to actual needs flexible modulation compensating parameter to reach desirable,
Without using inductance, output signal is filtered；
5th, the present invention is used as magnetic balance element by the magnetic core made using high magnetic conductance material, such that it is able to avoid external magnetic
The interference of field, improves the reliability of current detecting；
6th, the whole circuit of the present invention be suitable for device be general-purpose device, therefore facilitate implementation, and in the present invention circuit and
Magnetic circuit is separated, replaces such that it is able to flexible.
7th, with current system output, (that is, secondary coil output is record straight to required current measurement value in the present invention
Stream electric current or alternating current), therefore, can be easy to be transformed to magnitude of voltage according to actual needs (for example by defeated in secondary coil
Go out end series connection one resistance and realize conversion).
In a word, the present invention significantly improves performance (for example, the long-time stability: ＜ 2ppm/24h of sensor；Precision (line
Property degree): ＜ 10ppm；0.7ppm/ DEG C of temperature coefficient ＜；Wide-range: 0.1ma-3ka), and there is low in energy consumption, diamagnetic interference energy
Power is strong, structure is simple, lightweight, fast response time, sensitivity is high, interchangeability is good and installs, calibration, debugging, safeguard equal ten
Divide the advantages of facilitate.
Brief description
Fig. 1 is a kind of theory diagram of present invention alterating and direct current flow sensor；
Fig. 2 is a kind of circuit structure diagram of direct current signal detector unit in the present invention；
Fig. 3 is a kind of circuit structure diagram of direct current signal processing unit in the present invention；
Fig. 4 is another kind of circuit structure diagram of direct current signal detector unit in the present invention；
Fig. 5 is another kind of circuit structure diagram of direct current signal processing unit in the present invention；
Fig. 6 is the circuit structure diagram of AC signal processing unit in the present invention；
Fig. 7 is the theory diagram of restoring circuit unit in the present invention；
Fig. 8 is the circuit structure diagram of restoring circuit unit in the present invention；
Fig. 9 is the circuit structure diagram of power amplification unit in the present invention；
Figure 10 is waveform detection principle diagram in the present invention.
Specific embodiment
Below in conjunction with the accompanying drawings, provide presently preferred embodiments of the present invention, and be described in detail.
As shown in figure 1, the present invention, i.e. a kind of alterating and direct current flow sensor, comprising:
High magnetic conduction transformer unit t, comprising:
First magnetic core independent of each other and the second magnetic core；
It is wound on the first magnet exciting coil l1 on the first magnetic core and the second magnetic core and the second magnet exciting coil l2 respectively, wherein,
The number of turn of the first magnet exciting coil l1 is n1, and the number of turn of the second magnet exciting coil l2 is n2, and n1 can identical with n2 it is also possible to not
With；
3rd magnetic core, it is stacked together with the first magnetic core and the second magnetic core, to form a whole magnetic core, wherein, first,
Second and the 3rd magnetic core made by high permeability material；And
It is wound on primary coil l3, secondary coil l4 and the ancillary coil l5 on whole magnetic core, wherein, primary coil l3's
The number of turn is np, and this primary coil l3 receives the measured DC of periphery input or tested alternating current (i), secondary coil l4
The number of turn be ns, and the secondary coil l4 DC current that records of output or alternating current (output), the number of turn of ancillary coil l5
For n；
Pumping signal generating unit 1, it is connected with the first magnet exciting coil l1 and the second magnet exciting coil l2, with respectively to
One magnet exciting coil l1 and the second magnet exciting coil l2 provides the exciting current of 180 ° of two phase differences；
Direct current signal detector unit 2, it is connected with the second magnet exciting coil l2, to receive tested direct current in primary coil l3
During stream, receive the asymmetric accordingly magnetization signal of the second magnet exciting coil l2 output, and this asymmetric magnetization signal is converted to
Detectable voltage signals；
Direct current signal processing unit 3, it is connected with direct current signal detector unit 2, enters to receive and to detectable voltage signals
Row respective handling, and export corresponding direct current process signal；
Restoring circuit unit 4, it is connected with direct current signal detector unit 2, with reception and detectable voltage signals are pre- with one
If magnitude of voltage compares, and export corresponding demagnetization oscillator signal；
AC signal processing unit 5, it is connected with ancillary coil l5, to receive tested alternating current in primary coil l3
When, receive the corresponding sensor current signal of ancillary coil l5 output, and respective handling is carried out to this sensor current signal, with defeated
Go out corresponding exchange process signal；And
Power amplification unit 6, its input respectively with direct current signal processing unit 3, restoring circuit unit 4 and exchange letter
Number processing unit 5 connects, and its output end is connected with secondary coil l4, thus receiving direct current process signal, and to secondary coil l4
Export a DC compensation electric current, and receive demagnetization oscillator signal, be used for making the second magnetic core demagnetization to secondary coil l4 output one
Demagnetization current, or receive exchange process signal, and export an AC compensation electric current, wherein, DC compensation to secondary coil l4
In opposite direction and its size of current of electric current and measured DC is np/ns times of this measured DC, AC compensation
In opposite direction and its size of current of electric current and tested alternating current is np/ns times of this tested alternating current.
As shown in figure 1, in the present embodiment, pumping signal generating unit 1 is connected with the different name end of the first magnet exciting coil l1,
And be connected with the Same Name of Ends of the second magnet exciting coil l2.However, pumping signal generating unit 1 can also be with the first magnet exciting coil l1's
Same Name of Ends connects, and is connected with the different name end of the second magnet exciting coil l2.Pumping signal generating unit 1 in the present embodiment include according to
The signal source 11 of secondary connection and signal amplifier 12, wherein, signal source 11 refers to general signal generating circuit, its letter producing
Number include: the no signal such as the AC sine wave of direct current biasing, square wave, triangular wave, sawtooth waveforms, trapezoidal wave, signal amplifier 12 with
First magnet exciting coil l1 and the second magnet exciting coil l2 connects.
As shown in Fig. 2 a kind of embodiment (adopting phase frequency detection principle) of the direct current signal detector unit 2 in the present invention
Including: phased door 21, its input receives the asymmetric magnetization signal of the second magnet exciting coil l2 output and the phase of periphery input
Control signal, its output end passes sequentially through first resistor r1 and the first electric capacity c1 is grounded, wherein, first resistor r1 and the first electric capacity c1
Connected end to direct current signal processing unit 3 export detectable voltage signals.There is the direct current signal detector unit 2 of said structure
Operation principle is: by the break-make from phased gate control phased signal, therefrom detects tested current signal, phased signal is selected
4 frequencys multiplication of driving frequency, from phased signal control asymmetric magnetization signal in positive-negative half-cycle respectively via first resistor r1 to
One electric capacity c1 charges, and after a tested signal period, the voltage on the first electric capacity c1 is exactly as detectable voltage signals.
As shown in figure 3, for the direct current signal detector unit 2 using phase frequency detection principle, the direct current signal in the present invention
A kind of embodiment of processing unit 3 includes: the first operational amplifier 31, and its positive input terminal passes sequentially through 3rd resistor r3 and second
Resistance r2 receives detectable voltage signals, and its output end exports direct current process signal to power amplification unit 6, and passes through the 5th according to this
Resistance r5 and the 4th resistance r4 ground connection, its negative input end connects between the 4th resistance r4 and the 5th resistance r5, and wherein, the 3rd is electric
The connected end of resistance r3 and second resistance r2 passes through the second electric capacity c2 ground connection.In above-mentioned direct current signal processing unit 3, with first
Operational amplifier 31 is core, and second, third resistance r2, r3 and the second electric capacity c2 realizes filtering, the four, the 5th resistance r4,
R5 realizes gain, finally realizes direct current signal and processes.
As shown in figure 4, another kind of embodiment of the direct current signal detector unit 2 in the present invention (adopts peak detection former
Reason) include: the first diode d1, its positive pole receives the asymmetric magnetization signal of the second magnet exciting coil l2 output, and its negative pole passes through
3rd electric capacity c3 ground connection, passes through the 6th resistance r6 simultaneously and exports detectable voltage signals to direct current signal processing unit 3；And second
Diode d2, its negative pole receives the asymmetric magnetization signal of the second magnet exciting coil l2 output, and its positive pole is connect by the 4th electric capacity c4
Ground, passes through the 7th resistance r7 simultaneously and exports detectable voltage signals, wherein, the first diode d1's to direct current signal processing unit 3
Positive pole is connected with the negative pole of the second diode d2 to accept asymmetric magnetization signal, the 6th resistance r6 be connected with the 7th resistance r7 with
Output detectable voltage signals.In above-mentioned direct current signal detector unit 2, the resistance of the 6th resistance r6 and the 7th resistance r7 is larger,
6th resistance r6, the 3rd electric capacity c3 and the 7th resistance r7, the time constant of the 4th electric capacity c4 are far longer than asymmetric magnetization letter
Number cycle, asymmetric magnetization signal be positive peak when first diode d1 conducting, thus to the 3rd electric capacity c3 charge, work as quilt
When asymmetric magnetization signal is negative peak, the second diode d2 conducting, thus charge to the 4th electric capacity c4, through asymmetric magnetization
After a cycle of signal, the three, the 4th electric capacity c3, c4 reach respective maximum, by the six, the 7th resistance r6, r7
Do add operation, obtain detectable voltage signals.
As shown in figure 5, for the direct current signal detector unit 2 using peak detection principle, the direct current signal in the present invention
Another kind of embodiment of processing unit 3 includes: the second operational amplifier 32, and its positive input terminal passes through the 8th resistance r8 ground connection, its
Negative input end passes through the 9th resistance r9 and receives detectable voltage signals, and its output end processes letter to power amplification unit 6 output direct current
Number, and connected to the negative input end and the 9th resistance r9 of this second operational amplifier 32 by the tenth resistance r10, wherein,
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, the nine, the tenth resistance r9, r10 and the 5th electric capacity c5 jointly realize signal filtering and improve gain, thus completing to hand over
Stream signal transacting, the 8th resistance r8 completes the signal input ground connection of the second operational amplifier 32.
As shown in fig. 6, the AC signal processing unit 5 in the present invention includes: the 3rd operational amplifier 51, its positive input terminal
It is grounded by the 11st resistance r11, its negative input end passes through the induced-current that the 12nd resistance r12 receives ancillary coil l5 output
Signal, its output end exports exchange process signal to power amplification unit 6, and wherein, the 12nd resistance r12 and the 3rd computing are put
The connected end of the negative input end of big device 51 passes sequentially through the 13rd resistance r13 and the 6th electric capacity c6 ground connection, the 3rd operational amplifier
It is parallel with the 14th resistance r14 between 51 negative input end and output end.
As shown in fig. 7, the restoring circuit unit 4 in the present invention includes: the signal comparison module 41 that is sequentially connected, multiple-harmonic
Oscillator 42 and signal driver 43, wherein, signal comparison module 41 receives the detection voltage of direct current signal detector unit 2 output
Signal, signal driver 43 exports demagnetization oscillator signal to power amplification unit 6.Show in Fig. 8 in the present embodiment, signal ratio
Compared with the particular circuit configurations of module 41, multi resonant wave oscillator 42 and signal driver 43, for example, signal comparison module 41 includes:
Comparator 411, the 20th, 21 resistance r20, r21 and the 8th electric capacity c8；Multi resonant wave oscillator 42 includes: timer
421st, the the 20th the two to two ten four resistance r22-r24 and the 9th electric capacity c9；Signal driver 43 includes: triode q1 and
20 five to two ten seven resistance r25-r27 are (due to above-mentioned signal comparison module 41, multi resonant wave oscillator 42 and signal driver 43
Be this area conventional device, thus its structure here is omitted).
As shown in figure 9, the power amplification unit 6 in the present invention includes: four-operational amplifier 61, its positive input terminal passes through
15th resistance r15 ground connection, its negative input end passes through the 16th resistance r16 respectively to be received exchange process signal, passes through the 17th
Resistance r17 receives direct current process signal and receives demagnetization oscillator signal, its output end and secondary wire by the 18th resistance r18
Circle l4 connects, and wherein, is parallel with the 7th electric capacity being sequentially connected between the negative input end of four-operational amplifier 61 and output end
C7 and the 19th resistance r19.In above-mentioned power amplification unit 6, with the 7th electric capacity c7 and the 19th resistance r19 and the 16th
Constitute negative-feedback constant gain loop to the 18th resistance r16-r18, realize power and steadily export, the 15th resistance r15 completes
The input signal ground connection of four-operational amplifier 61.Power amplification unit 6 receive direct current or AC signal processing unit 3 or 5 with
And the signal that restoring circuit unit 4 provides, make the electric current of the current canceling primary coil l3 of secondary coil l4, realize magnetic core standard zero
Magnetic flux (concrete principle is described below).
The operation principle of the present invention is as follows:
In the present invention, first, second magnet exciting coil l1, l2 cooperation pumping signal, signal detection, signal transacting and power are put
The link such as big completes the current measurement of dc- tens hz.Specifically, the different ends difference of first, second magnet exciting coil l1, l2
Be connected with pumping signal generating unit 1, therefore in this two inductance produce magnetic flux for secondary coil l4, amplitude phase
Deng, in opposite direction, thus eliminating the impact to measured value for the pumping signal, reduce the background noise of measurement.
For convenience of describing, here, assume swashing of pumping signal generating unit 1 output taking the second magnet exciting coil l2 as a example simultaneously
Encourage signal for square wave measurement process to be described: the exciting current waveform in the second magnet exciting coil l2 referring to can Figure 10, encouraged with this
Current signal is as carrier wave.When tested electric current is zero, the signal integration of detection detection is zero, when tested electric current is not zero,
The signal integration of detection detection is not zero, and the signal that this is not zero gives power amplification unit 6, thus producing on secondary coil l4
Give birth to primary coil l3 ampere-turn identical electric current the magnetizing current waveform symmetry so that on the second magnet exciting coil l2, and then make inspection
It is zero that ripple detects；When having alternating current in primary coil l3, ancillary coil l5 senses the current signal of primary coil l3,
This signal delivers to power amplification unit 6, so that producing and the contrary electric current of primary coil l3 electric current and width on secondary coil l4
Value is np/ns times of tested electric current, and then completes ac current measurement (to 100khz).
Restoring circuit unit 4 can ensure entirely to feed back and is in controllable state, specifically, when booting moment or primary line
When circle l3 has excessively stream etc. impact, the negative-feedback working condition of whole circuit will be destroyed.Under normal circumstances, by high magnetic conduction material
Second magnet exciting coil l2 of material composition is operated in the presence of pumping signal and easily enters saturation shape close to the region of saturation
State, when strong jamming destroys negative-feedback, circuit enters positive feedback, and power amplification unit 6 exports positive or negative maximum voltage value, leads
Cause the positive or negative maximum current of secondary coil l4 output, the magnetic core of the second magnet exciting coil l2 enters saturation state, even if interference letter
Number remove, the magnetic core of l2 nor the state before automatically returning to interference.Therefore, specially devise detection the second excitation in the present invention
The circuit of coil l2 magnetic core working condition, when the magnetic core saturation of the second magnet exciting coil l2, the second magnet exciting coil l2 loses inductance effect
With the asymmetric magnetization signal that direct current signal detector unit 2 detects exceedes setting value, the multiple-harmonic in restoring circuit unit 4
Oscillator, produce far below exciting signal frequency square wave, and through signal driver send into power amplification unit 6, this signal and
The signal subtraction that direct current signal processing unit 3 is sent as the input of power amplification unit 6, when above-mentioned two signal subtractions are zero
When, power amplification unit 6 exports no-voltage, and the magnetic core of the second magnet exciting coil l2 exits saturation state, and whole circuit is again introduced into
Negative-feedback state, when the signal of direct current signal detector unit 2 detection is less than setting value, then restoring circuit unit 4 quits work,
Recovery process terminates, and completes the correction of magnetic core magnetic bias.
Based on above-mentioned principle, when there is D.C. magnetic biasing in magnetic core, ac-excited signal is in first, second magnet exciting coil
Electric current on l1, l2 arises that the asymmetric distorted waveform of positive and negative half-wave, and direct current signal detector unit 2 obtains exciting current letter
Number asymmetric situation, by after positive and negative for this asymmetric waveform half wave conversion formed voltage signal deliver to direct current signal processing unit
3, treated signal promotes the electric current of power amplification unit 6 generation and reciprocal ns/np times of measured DC, with flat
Magnetic bias magnetic potential produced by weighing apparatus measured DC, thus forming " quasi- Zero flux state ", and then realizes the detection of DC current
Task.
In the same manner, when tested electric current be alternating current when, in magnetic core formed alternating current biasing, ancillary coil l5, primary coil l3,
Secondary coil l4 and power amplification unit 6 complete ac current measurement jointly.
When magnetic core state deviates quasi- Zero flux state, ac-excited signal is on first, second magnet exciting coil l1, l2
Electric current arises that positive and negative half-wave asymmetric limit distorted waveform, when direct current signal testing circuit obtains maximum asymmetric magnetization
During signal, then start restoring circuit unit 4, AC demagnetization is carried out to magnetic core, makes magnetic core come back to the controlled shape of quasi- Zero flux
State.
In other words, in the present invention, alternating message source magnetizes to first, second magnet exciting coil l1, l2, in outside
During tested electric current i=0, first, second magnet exciting coil l1, l2 phase-inversion symmetric magnetization, the magnetization signal both forward and reverse directions amplitude of output
Equal direction is contrary, and the asymmetric magnetization signal of direct current signal detector unit 2 detection is zero, direct current signal processing unit 3 and work(
Rate amplifying unit 6 is all exported with zero-signal.
When DC current i ≠ 0, second magnetic core of the second magnet exciting coil l2 is magnetized, and pumping signal is in the second excitation wire
Magnetization on circle l2 occurs as soon as asymmetric, and this asymmetric magnetization signal is directly proportional or inverse ratio to tested electric current, direct current signal detection
After unit 2 detects this asymmetric magnetization signal, deliver to direct current signal processing unit 3 by a certain percentage, through signal transacting it
Promote that power amplification unit 6 produces and the tested sense of current is contrary afterwards, and amplitude is the electric current of np/ns times of tested electric current, thus
Produce and the rightabout direct current magnetic potential of magnetic potential produced by tested direct current, to balance magnetic bias magnetic potential produced by tested direct current,
And then so that the magnetic flux in magnetic core is close to zero, complete the Zero flux magnetic balance in popular saying, therefore can obtain tested direct current
Size, 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 completes transformer current conversion, realizes magnetic core Zero flux magnetic balance, as transformer, thus realizing the detection of alternating current
Task.
Restoring circuit unit 4, by comparing the asymmetric magnetization signal that direct current signal detector unit 2 is delivered to, judges the second magnetic
Whether normal the magnetized state of core is, and when the magnetization of the second magnetic core has exceeded setting value, restoring circuit unit 4 then starts demagnetization vibration
Signal, promotes power amplification unit 6 to produce high current and completes demagnetization process；After demagnetization terminates, demagnetization oscillator signal stops, whole
Body circuit to complete profound and negative feedbck by direct current signal processing unit 3 according to detectable voltage signals driving power amplifying unit 6.
In sum, the ingehious design of the present invention is so that when tested electric current is direct current or exchange, automatically switching, automatically complete
Become current measurement；The present invention is adapted to detect for 0hz-100khz electric current, for example, be applied to: the current feedback of power electronic equipment, cut
The alternating current-direct current of the industries such as flow control, high-accuracy steady-flow regulation, over-current detection, accelerator magnet power supply, power system and electrolysis
Current signal detects.
Above-described, only presently preferred embodiments of the present invention, it is not limited to the scope of the present invention, the present invention's is upper
State embodiment can also make a variety of changes.I.e. every claims according to the present patent application and description are made
Simply, equivalence changes and modification, falls within the claims of patent of the present invention.Being of the not detailed description of the present invention
Routine techniques content.
Claims (13)
1. a kind of alterating and direct current flow sensor is it is characterised in that described sensor includes:
High magnetic conduction transformer unit, comprising:
First magnetic core independent of each other and the second magnetic core；
It is wound on the first magnet exciting coil on described first magnetic core and the second magnetic core and the second magnet exciting coil respectively；
3rd magnetic core, it is stacked together with described first magnetic core and the second magnetic core, to form a whole magnetic core；And
It is wound on primary coil on described whole magnetic core, secondary coil and ancillary coil, wherein, the number of turn of described primary coil
For np, and described primary coil receives the measured DC of periphery input or tested alternating current, the circle of described secondary coil
Number is ns, and described secondary coil exports the DC current recording or alternating current；
Pumping signal generating unit, it is connected with described first magnet exciting coil and described second magnet exciting coil, with respectively to institute
State the first magnet exciting coil and the second magnet exciting coil provides the exciting current of 180 ° of two phase differences；
Direct current signal detector unit, it is connected with described second magnet exciting coil, described tested straight to receive in described primary coil
During stream electric current, receive the asymmetric accordingly magnetization signal of described second magnet exciting coil output, and by this asymmetric magnetization signal
Be converted to detectable voltage signals；
Direct current signal processing unit, it is connected with described direct current signal detector unit, with reception and to described detectable voltage signals
Carry out respective handling, and export corresponding direct current process signal；
Restoring circuit unit, it is connected with described direct current signal detector unit, to receive and by described detectable voltage signals and
Preset voltage value compares, and exports corresponding demagnetization oscillator signal；
AC signal processing unit, it is connected with described ancillary coil, to receive described tested alternating current in described primary coil
During stream, receive the corresponding sensor current signal of described ancillary coil output, and respective handling carried out to this sensor current signal,
To export corresponding exchange process signal；And
Power amplification unit, its input respectively with described direct current signal processing unit, restoring circuit unit and AC signal
Processing unit connects, and its output end is connected with described secondary coil, thus receiving described direct current process signal, and to described secondary
Coil exports a DC compensation electric current, and receives described demagnetization oscillator signal, is used for making described to described secondary coil output one
The demagnetization current of the second magnetic core demagnetization, or receive described exchange process signal, and mend to described secondary coil output one exchange
Repay electric current, wherein, described DC compensation electric current is this quilt with opposite direction and its size of current of described measured DC
Survey DC current np/ns times, with the in opposite direction of described tested alternating current and its electric current is big for described AC compensation electric current
Little is np/ns times of this tested alternating current.
2. alterating and direct current flow sensor according to claim 1 it is characterised in that the number of turn of described first magnet exciting coil with
The number of turn of described second magnet exciting coil is identical or different.
3. alterating and direct current flow sensor according to claim 1 is it is characterised in that described pumping signal generating unit and institute
The different name end stating the first magnet exciting coil connects, and is connected with the Same Name of Ends of described second magnet exciting coil.
4. alterating and direct current flow sensor according to claim 1 is it is characterised in that described pumping signal generating unit and institute
The Same Name of Ends stating the first magnet exciting coil connects, and is connected with the different name end of described second magnet exciting coil.
5. the alterating and direct current flow sensor according to claim 1,3 or 4 is it is characterised in that there is list in described pumping signal
Unit includes the signal source that is sequentially connected and a signal amplifier, wherein, described signal amplifier and described first excitation wire
Circle and described second magnet exciting coil connect.
6. alterating and direct current flow sensor according to claim 1 is it is characterised in that described direct current signal detector unit bag
Include: phased door, its input receives described asymmetric magnetization signal and the phased signal of a periphery input, and its output end is successively
By first resistor and the first capacity earth, wherein, the connected end output described detection electricity of described first resistor and the first electric capacity
Pressure signal.
7. alterating and direct current flow sensor according to claim 6 is it is characterised in that described direct current signal processing unit bag
Include: the first operational amplifier, its positive input terminal passes sequentially through 3rd resistor and second resistance receives described detectable voltage signals, its
Output end export described direct current process signal, and according to this pass through the 5th resistance and the 4th resistance eutral grounding, its negative input end connect to
Between described 4th resistance and the 5th resistance, wherein, the connected end of described 3rd resistor and second resistance is connect by the second electric capacity
Ground.
8. alterating and direct current flow sensor according to claim 1 is it is characterised in that described direct current signal detector unit bag
Include: 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 connect
Receive described asymmetric magnetization signal, the negative pole of described first diode is passed through the 3rd capacity earth, is connected with the 6th resistance simultaneously,
The positive pole of described second diode passes through the 4th capacity earth, is connected with the 7th resistance simultaneously, and described 6th resistance and the 7th
Resistance is connected to export described detectable voltage signals.
9. alterating and direct current flow sensor according to claim 8 is it is characterised in that described direct current signal processing unit bag
Include: the second operational amplifier, its positive input terminal passes through the 8th resistance eutral grounding, and its negative input end passes through the 9th resistance and receives described inspection
Survey voltage signal, its output end exports described direct current process signal, and connects to this second operational amplifier by the tenth resistance
Negative input end and described 9th resistance between, wherein, described tenth resistance two ends are parallel with the 5th electric capacity.
10. alterating and direct current flow sensor according to claim 1 is it is characterised in that described AC signal processing unit bag
Include: the 3rd operational amplifier, its positive input terminal passes through the 11st resistance eutral grounding, and its negative input end passes through the 12nd resistance and receives institute
State sensor current signal, its output end exports described exchange process signal, and wherein, described 12nd resistance is put with the 3rd computing
The connected end of the negative input end of big device passes sequentially through the 13rd resistance and the 6th capacity earth, described 3rd operational amplifier negative
It is parallel with the 14th resistance between input and output end.
11. alterating and direct current flow sensor according to claim 1 are it is characterised in that described restoring circuit unit includes: according to
The signal comparison module of secondary connection, multi resonant wave oscillator and signal driver, wherein, described signal comparison module receives described inspection
Survey voltage signal, described signal driver exports described demagnetization oscillator signal.
12. alterating and direct current flow sensor according to claim 1 are it is characterised in that described power amplification unit includes: the
Four-operational amplifier, its positive input terminal passes through the 15th resistance eutral grounding, and its negative input end passes through the 16th resistance respectively and receives institute
State exchange process signal, receive described direct current process signal by the 17th resistance and by moving back described in the 18th resistance reception
Magnetic oscillation signal, its output end is connected with described secondary coil, wherein, the negative input end of described four-operational amplifier and output
It is parallel with the 7th electric capacity being sequentially connected and the 19th resistance between end.
13. alterating and direct current flow sensor according to claim 1 it is characterised in that described first magnetic core, the second magnetic core and
3rd magnetic core is made by high permeability material.
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Application publication date: 20141008 Assignee: SHANGHAI AIPUQIANG PARTICLE EQUIPMENT Co.,Ltd. Assignor: SHANGHAI INSTITUTE OF APPLIED PHYSICS, CHINESE ACADEMY OF SCIENCES Contract record no.: X2019310000019 Denomination of invention: Alternating current/direct current sensor Granted publication date: 20170118 License type: Exclusive License Record date: 20191113 |
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