CN106018915A - Current detector - Google Patents
Current detector Download PDFInfo
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- CN106018915A CN106018915A CN201610192052.2A CN201610192052A CN106018915A CN 106018915 A CN106018915 A CN 106018915A CN 201610192052 A CN201610192052 A CN 201610192052A CN 106018915 A CN106018915 A CN 106018915A
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- amperometric
- alternating current
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
- G01R15/202—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices using Hall-effect devices
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- General Physics & Mathematics (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Measuring Magnetic Variables (AREA)
Abstract
The invention provides a current detector and especially a technology for eliminating the influences of hysteresis by a simple strucure without complex action. The current detector (100) comprises a magnetic body core (102) which is arranged in a ring along the surrounding direction of a magnetic field generated when a detected current (If) is conducted, wherein an interval (102d) for arranging a Hall element (106) is formed on a part; and a demagnetization circuit (150) which applies an alternating current with preset attenuation characteristics and a frequency in a preset range for a demagnetization coil (156) of the magnetic body core (102) so as to eliminate the residual magnetic flux in the magnetic body core (102).
Description
Technical field
The present invention relates to the use of magnetic core and collect conducting based on sensed current and the electric current of the type of magnetic flux that produces
Detector.
Background technology
There is in the amperometric of the type of this employing magnetic core following such problem, i.e. when in action in leading
When internal generation is well beyond the overcurrent of rated value, due to the relict flux of magnetic core, accuracy of detection is produced impact (residual
So-called magnetic hysteresis).Therefore, at present in the DC current sensor with detection magnetic core and detection coil, it is known to be conceived to
Eliminate the prior art of magnetic hysteresis of detection magnetic core (for example, referring to patent documentation 1.).
The prior art relate to for make the magnetic field produced when sensed current turns on carry out the detection magnetic core that collects with
Vertical direction links the DC current sensor of excitation being integrally forming of magnetic core making one part generation magnetic gaps, as electricity
Flow sensor is the most special form.I.e., although the excitation magnetic core integrated with detection magnetic core produces alternating magnetic field, makes detection magnetic
A part for core periodically becomes the gap state of magnetic, but in gap is formed, magnetic switch, for turning off, disappears in gap
In, magnetic switch, for connecting, produces electromotive force so this can be utilized repeatedly to come in detection coil, carries out current detecting.But,
The impact of the coercive force having due to soft magnetic material under this state and resulted in the output voltage of Autonomous test coil
The hysteresis of (output characteristics), therefore to make to produce in modulation coil by detection magnetic core is configured modulation coil further
Raw alternating magnetic field is overlapping with detection magnetic core and measures the DC current of flowing in detected wire, eliminates above-mentioned guarantor's magnetic
The impact of power.
On this basis, prior art is conceived to when being energized modulation coil in current detecting, small
Galvanic areas in testing circuit electrically reaching saturated, thus be difficult to from adjusting by the detection signal that obtains of coil separates
Ac current signal processed and the such situation of tested constant current signal, during resetting de-magnetic, become and take off magnetic state completely, then
During detection is set, saturated with the electricity preventing testing circuit.
Prior art literature
Patent documentation
Patent documentation 1: Japanese Unexamined Patent Publication 10-68744 publication (paragraph 0018-0023 etc.)
Summary of the invention
Invent problem to be solved
But, above-mentioned prior art has difficulty in complexity based on its specific form.That is, to original inspection
Survey in the structure that magnetic core adds modulation coil with excitation magnetic core, in order to remove the magnetic caused by the coercive force that detection magnetic core has
Stagnant, and make in modulation coil produce alternating magnetic field specially with detection magnetic core carry out overlapping, but the most obviously detection coil with
Testing circuit is attached all the time.But, during the de-magnetic reset in need the electricity preventing testing circuit saturated, connect down
Come from testing circuit separation detection coil, and, during de-magnetic at the end of must again reconnect such multiple
Miscellaneous action.
Therefore, the invention provides without adjoint complicated action, utilize easy structure to eliminate the impact of magnetic hysteresis
Technology.
The means of solution problem
In order to solve above-mentioned problem, the present invention uses following solution.
That is, magnetic detecting element is configured in the present invention is the gap formed in magnetic material core to detect the type of electric current
Amperometric, it is suitable for so-called opening, the type of the such orthodox form of servo type.
On this basis, the present invention has degaussing circuit, this degaussing circuit in magnetic material core arrange around
Group, applies the alternating current with predetermined attenuation characteristic, thus eliminates in magnetic material core with the frequency in preset range
The magnetic flux of residual.
According to the amperometric of the present invention, even if producing the shadow of the magnetic hysteresis caused by the relict flux of magnetic material core
Ring, it is also possible to utilize the alternating current that degaussing circuit is applied to remove magnetic hysteresis.It addition, because of the mensuration in sensed current
(detection of electric current) uses magnetic detecting element, so need not with in the applying of alternating current produced by degaussing circuit
Separate the such compound action of any electrical connection, afterwards re-attached, easy structure can be become.
In the present invention, in the way of degaussing circuit preferably frequency in the range of 8kHz to 17kHz applies alternating current.
Other characteristic such as the scope of such frequency and the coercive force of the rated value of sensed current or magnetic material core is unrelated, has
Versatility.Therefore, there is no need to scrutinize an other characteristic to determine frequency, it is possible to obtain simple and that convenience is high electric current inspection in advance
Survey device.
It addition, in the present invention, degaussing circuit applies as predetermined attenuation characteristic, and die-away time is 5ms to 1000ms
Alternating current.Additionally, because after die-away time, complete to remove the magnetic caused by relict flux of magnetic material core
Stagnant, so need not repeatedly apply alternating current later, the detection of electric current can be directly proceeded with.
The amperometric of the present invention may be configured as the servo type with feedback circuit.In the case, degaussing circuit can
The Secondary Winding of feedback circuit is applied alternating current.Thus, it is not necessary to other special winding is set, it becomes possible to by winding
Usage amount is suppressed to less.
It addition, in the present invention, degaussing circuit preferably beginning alternating current from the moment of the conducting starting sensed current
The mode of the applying of stream.Or, degaussing circuit can start to execute from starting the moment to magnetic detecting element supply driving power
Add alternating current.
That is, the conducting of sensed current starts or magnetic detecting element supply drives the supply of power start to mean to answering
The moment of power supply is put into by some system (electrical equipment) of the amperometric of the present invention.By at such moment demagnetization electricity
Road starts to apply alternating current, and decays with it and remove the impact of magnetic hysteresis together, it is possible to make the amperometric power supply from system
Input is just stablized and is carried out detection action accurately at the beginning of starting.
Invention effect
According to the present invention, it is not necessary to complicated action, it is possible to eliminate the impact of magnetic hysteresis with easy structure.
Accompanying drawing explanation
Fig. 1 is the axonometric chart of the structure of the amperometric briefly illustrating the 1st embodiment.
Fig. 2 is the figure briefly illustrating degaussing circuit to the waveform of the alternating current that demagnetization coil is applied.
Fig. 3 is briefly to illustrate the experimental model (current detecting for confirming to use the magnetic hysteresis removal effect of degaussing circuit
Device is sampled) the figure of structure.
Fig. 4 is the figure of the result illustrating that magnetic hysteresis removes test.
Fig. 5 is to illustrate the figure of the result that the frequency setting of alternating current is magnetic hysteresis removal effect during 10kHz.
Fig. 6 is that the measurement result according to Fig. 5 makes the virtual value of the alternating current figure curved with the relation of magnetic hysteresis variable quantity.
Fig. 7 (A), Fig. 7 (B) are the condition various asynchronous examinations of holding of the frequency illustrating the electric current making applying and current value
Test the figure of result.
Fig. 8 (A), Fig. 8 (B) are the condition various asynchronous examinations of holding of the frequency illustrating the electric current making applying and current value
Test the figure of result.
Fig. 9 is the skeleton diagram of the structure of the amperometric illustrating the 2nd embodiment.
Figure 10 is the skeleton diagram of the structure of the amperometric illustrating the 3rd embodiment.
Figure 11 be illustrate the 1st, the 2nd, the skeleton diagram of the structure of the degaussing circuit of the 3rd embodiment.
Label declaration
100,200,300 amperometric
102 magnetic material core
102d gap
104 Secondary Winding
106 Hall elements
108 special circuits
150 degaussing circuits
Detailed description of the invention
Hereinafter, it is explained with reference to embodiments of the present invention.
[the 1st embodiment]
Fig. 1 is the skeleton diagram of the structure of the amperometric 100 illustrating the 1st embodiment.Hereinafter, amperometric is described
The structure of 100.
[magnetic material core]
Amperometric 100 possesses the magnetic material core 102 using permalloy the most in the material, this magnetic material core
102 as being monolithically fabricated approximation square ring shape.The electricity of approximate rectangular shape is formed in the inner side (inner circumferential of ring) of magnetic material core 102
Stream conducting portion 102a, inserts the conductors 105 (winding) such as bus (bus bar) in this current lead-through portion 102a.Electric current is examined
Survey device 100 using by the electric current of conductor 105 as detection object, along conductor 105 in flow sensed current (If) time product
The cincture direction in raw magnetic field, configuration magnetic material core 102 annularly.Additionally, be than relatively low water in sensed current (If)
Time accurate (weak current), conductor 105 can be wound in magnetic material core 102.
[gap]
As described above, magnetic material core 102 constitutes approximation square ring shape, therefore, contains respectively in magnetic material core 102
There is pair of short edges portion 102b and long leg 102c.It addition, in magnetic material core 102, such as long by partly cutting 1
The midway of edge 102c forms gap 102d.Additionally, gap 102d can be formed at short leg 102b.
[magnetic detecting element]
Amperometric 100 is as an example of magnetic force detection element, and possessing Hall element 106 (can be MR element, MI
Element).Hall element 106 is installed in magnetic material core 102 when being inserted in the 102d of gap.Additionally, Hall
Element 106 for example is by the electronic unit that resin seal is packaged, in each Hall element 106, such as by not
The power circuit of diagram supplies driving voltage (such as+5V).Hall element 106 output and the magnetic field produced in the 102d of gap
The corresponding voltage signal (Hall voltage) of intensity (magnetic flux).
[special circuit]
It addition, amperometric 100 possesses special circuit 108.This special circuit 108 is e.g. towards the 1st embodiment
The amperometric 100 of such servo type makes structural optimization the electronic unit of the circuit in enclosed inside special designs
(discrete (discrete) product).In special circuit 108, except from not shown power circuit supply driving voltage (such as+
Outside 5V), also input the voltage signal from Hall element 106 output.It addition, special circuit 108 has as reference port
REFIN and REFOUT (such as+2.5V).
[feedback circuit]
As described above, the amperometric 100 of the 1st embodiment is servo type, therefore possesses as feedback circuit
Element.Feedback circuit is except, such as in addition to having not shown differential amplifier in above-mentioned special circuit 108, also having
There is the Secondary Winding 104 being connected with special circuit 108.Such as, it is being wound in long leg 102c of magnetic material core 102
Secondary Winding 104 it is formed with under state.Secondary Winding 104 is according to the voltage signal from Hall element 106, and supply is at Special electric
The feedback current (Ih) generated in road 108, thus produces in the way of offsetting the direction in magnetic field produced by sensed current (If)
Raw counter field.Additionally, be provided with load resistance 110 in a feedback circuit, electric current output (Ih) of Secondary Winding 104 is via load
Resistance 110 is converted to voltage output (Vout).
[degaussing circuit]
It addition, amperometric 100 has degaussing circuit 150.This degaussing circuit 150 eliminates the residual of magnetic material core 102
Stay magnetic flux (so-called magnetic hysteresis removal).Therefore, magnetic material core 102 is wound with distinctively with above-mentioned Secondary Winding 104 disappears
Magnetic coil 156, degaussing circuit 150 applies alternating current to demagnetization coil 156.Specifically, degaussing circuit 150 has and shakes
Swing circuit 152 and attenuator circuit 154.Wherein, oscillating circuit 152 generates alternating current, decay electricity with the frequency of preset range
It is after-applied on demagnetization coil 156 that road 154 makes it decay.
The degaussing circuit with oscillating circuit and attenuator circuit such as can be constituted by circuit as shown in Figure 11.Resistance R, electric capacity
C, the constant of inductance L are not limited by the constant of Figure 11, can suitably change.
[AC wave shape]
Fig. 2 is the figure briefly illustrating degaussing circuit 150 to the waveform of the alternating current that demagnetization coil 156 is applied.
The oscillating circuit 152 of degaussing circuit 150 generates the alternating current (Ipp) such as represented by following formula.
Ipp=Vh/Vgain If
In above formula,
Vh: hysteresis voltage
Vgain:0.625V
If: sensed current (rated value).
It addition, by the frequency setting of alternating current (Ipp) in the range of 8kHz～17kHz.Attenuator circuit 154 makes exchange
Electric current (Ipp) over time through overdamping, start to cause greatly current value to become 0 in die-away time in Ts from applying.Here, will
Die-away time, Ts was such as set to 50ms.Additionally, Ts die-away time such as can be set in the range of 5ms～1000ms.
[setting of frequency range]
Here, illustrate the frequency setting of alternating current (Ipp) basis in the range of 8kHz～17kHz., based on
Under test carry out the scope of setpoint frequency.
[magnetic hysteresis removes test]
Fig. 3 is briefly to illustrate that (electric current is examined for confirming to use the experimental model of the magnetic hysteresis removal effect of degaussing circuit 150
Survey device sampling) the figure of structure.In experimental model, such as, make the electricity that test magnetic core 302 is the cascade type of silicon steel plate
Current sensor.It addition, be wound around above-mentioned demagnetization coil 156 on test magnetic core 302, and connect degaussing circuit 150.The opposing party
Face, is wound around the supervision coil 5 of flux change on test magnetic core 302, and makes it connect voltage monitor 160.In addition this
In, demagnetization writhing number for example, 13 circle of coil 156, monitor with writhing number for example, 5 circle of coil 5.
[experimental condition]
Magnetic hysteresis is removed test and is carried out the most under the following conditions.
(1) utilize demagnetizer that the magnetic core 302 of experiment amperometric carries out demagnetization, connect power supply ± 15V, utilize ten thousand
Bias voltage is measured with table.
(2) it is shutoff by the power settings of experiment amperometric.The magnetic core 302 of experiment amperometric is being passed through
After logical 10 times of rated current, power supply is made to become connection.The bias voltage of determination experiment amperometric.
(3) demagnetization coil 156 is energized, utilize voltage monitor 160 to monitor excitation waveform, when observing
During to excitation waveform, erasure effect is viewed as " having ".The signal making anti-magnetized coil 156 turns off, determination experiment current detecting
The output voltage (bias voltage) of device, makes the change of the bias voltage before and after anti-magnetized coil 156 action have erasure effect.
(4) after above-mentioned (3), temporarily test magnetic core 302 is carried out excitation, make test magnetic core 302 produce residual
Magnetic flux.43.8A × 13 (number of turn)=570AT is become by electric current.
(5) then, make degaussing circuit 150 carry out action in the way of removing magnetic hysteresis, and apply the friendship with attenuation characteristic
Stream electric current.
[result of the test]
Fig. 4 is the figure of the result illustrating that magnetic hysteresis removes test.Here, carry out 10 tests (No.1～No.10), make respectively
The various values of secondary middle acquisition become guide look.It addition, test in the way of each frequency changing applying electric current.
[mensuration project]
Mensuration project in test (frequency is based on setting) is as described below every time.
(1) bias voltage after demagnetization: Voffset (mV)
(2) magnetic hysteresis after excitation: VH (mV)
(3) RMS value (the A) × 13T of electric current is applied: become the winding several times of the alternating current of applying.
(4) magnetic hysteresis removal frequency (Hz): set frequency.
(5) bias voltage of (after demagnetization is tested): VOFFSET (mV) after electric current applying
(6) magnetic hysteresis removal effect (mV): make the difference of Voffset Yu VOFFSET become removal effect.
(7) monitor waveform: VRMS (mV), carry out the voltage RMS value of the waveform monitored with voltage monitor 160.
Hereinafter, result of the test is described.
[the 1st test]
In the diagram, as shown in the result of the test of " No.1 ", when being 10Hz by the frequency setting of the alternating current of applying,
Obtain some value (-9.29mV) as magnetic hysteresis removal effect (VOFFSET-Voffset), but do not observe supervision waveform.
[the 2nd test]
Then, in the diagram, as shown in the result of the test of " No.2 ", but it is 10 by the frequency setting of the alternating current of applying
Times 100Hz time, obtain some value (-5.80mV) as identical magnetic hysteresis removal effect (VOFFSET-Voffset), but still
So do not observe supervision waveform.
[the 3rd test]
Then, in the diagram, as shown in the result of the test of " No.3 ", when the frequency of the alternating current of applying is also set to
During the 1kHz of 10 times, also serve as magnetic hysteresis removal effect (VOFFSET-Voffset) here and obtain some value (-9.60mV), but depend on
So do not observe supervision waveform.
[the 4th test]
Therefore, in the diagram, as shown in the result of the test of " No.4 ", the frequency setting of the alternating current of applying is by this
8kHz.As a result, obtain good value (-11.25mV) as magnetic hysteresis removal effect (VOFFSET-Voffset), and observe
Monitor waveform (120mV).
[the 5th test]
Then, in the diagram, as shown in the result of the test of " No.5 ", by the frequency setting of the alternating current of applying it is
17kHz.The most also it is to obtain good value (-8.33mV) as magnetic hysteresis removal effect (VOFFSET-Voffset), and sees
Measure supervision waveform (156mV).
[after the 6th test]
It addition, in the diagram, as shown in the result of the test of " No.6 "～" No.8 ", though the frequency of the alternating current by applying
Rate gradually steps up as 20kHz, 25kHz, 30kHz, also obtain magnetic hysteresis removal effect value (-8.68mV ,-12.00mV ,-
9.12mV), supervision waveform (192mV, 307mV, 355mV) is observed.
Equally, the result of the test of " No.9 " and " No.10 " in Fig. 4 is, respectively setpoint frequency bring up to 50kHz,
100kHz.In these trials, it is thus achieved that the value (-10.75mV ,-11.88mV) of magnetic hysteresis removal effect, and observe supervision waveform
(575mV、1060mV)。
[summary (1) of result of the test]
According to above result of the test " No.1 "～" No.10 ", situation that can be clearly following.
(i) but to amperometric sampling demagnetization coil 156 apply alternating current time, as result obtain magnetic hysteresis go
The effect removed.
(ii) wherein, because there is no supervision waveform in less than the frequency domain of 8kHz, so at these lower frequency regions (10Hz
～1000Hz) under, in test magnetic core 302, do not show flux change.
(iii) on the other hand, because obtaining in the high-frequency domain of more than 8kHz and monitoring waveform, so understanding at test magnetic
The frequency occurring flux change in core 302 is more than 8kHz.
[mensuration of magnetic hysteresis removal effect]
Therefore, (being 12 times here) examination after the frequency setting of the alternating current of applying is 10kHz, is also carried out repeatedly
Test, and determine the magnetic hysteresis removal effect of each time.Additionally, experimental condition is same as shown in Figure 4.In this experiment, make every time
The RMS value of the alternating current applied is changed.
Fig. 5 is to illustrate the figure of the result that the frequency setting of alternating current is magnetic hysteresis removal effect during 10kHz.It addition,
Fig. 6 is the figure that the measurement result according to Fig. 5 draws the virtual value of alternating current and the relation of magnetic hysteresis variable quantity." magnetic hysteresis in Fig. 5
Removal effect (mV) " it is the difference of " magnetic hysteresis VH (mV) after excitation " and " Voffset (mV) ".It addition, " monitoring waveform VRMS
(mV) in column ", the situation for " ok " is to represent to observe effective waveform.Additionally, about each time " No.1 "～" No.12 "
In each measured value referring in detail to diagram content, omit the content mentioned individually here.
[summary (2) of result of the test]
According to above result of the test (No.1～No.12 in Fig. 5 and Fig. 6), situation that can be clearly following.
(i) when demagnetization coil 156 being applied alternating current with the frequency of 10kHz because partially in all number of times
Effective change is found, it is known that there is magnetic hysteresis removal effect in putting voltage.
(ii) now, when increasing the virtual value of the alternating current applied, the variable quantity of the bias voltage that accompanies with it is (definitely
Value) also present the tendency (there is deviation somewhat) that overall change is big.
[embodiment]
According to the result of the test using above amperometric to sample, at the servo type of the 1st embodiment shown in Fig. 1
Amperometric 100 in actual carried out magnetic hysteresis remove test.The purpose of this test is, as cutting off actually used electricity
The state of the power supply of the system (such as fridge) of current sensor 100, by the unidirectional current of 10 times of rated value in conductor 105
During stream, degaussing circuit 150 is utilized to remove the magnetic hysteresis of residual in magnetic material core 102.
[theoretical supposition]
Here, before actual test, according to raw material and special circuit 108 (the discrete product of magnetic material core 102
Product) characteristic, following theoretical property speculates to be set up.
(a) bias voltage (VOFFSET)=2.5V, rated current If=7A
B error that () is above-mentioned=± 20mV
C current value (value of calculation) that () magnetic hysteresis is suitable: according to the formula of Ipp=Vh/Vgain If, 20/625 × 7=
0.224A=224mA
(d) therefore, magnetic hysteresis remove current value in the range of 0mA to 224mA fluctuation while decay.
[result of the test]
Fig. 7 (A), Fig. 7 (B) and Fig. 8 (A), Fig. 8 (B) are the conditions of frequency and the current value illustrating the electric current making applying
Keep the figure of various asynchronous result of the test.Fig. 7 therein (A) represents makes the writhing number of demagnetization coil 156 become 1 time
(1T) result of the test time, Fig. 7 (B) and Fig. 8 (A), Fig. 8 (B) represent makes the writhing number of demagnetization coil 156 become 5 times
(5T) result of the test time.About the judgement with or without magnetic hysteresis removal effect, as long as the bias voltage after Shi Yan is in theoretic
Bias voltage=2.5V ± 10mV, it is determined that " having ", the judgement beyond it is "None".
Fig. 7 (A): the frequency of alternating current is set to 8kHz, utilizes the current value shown in each time (No.1～No.5) to taste
Magnetic hysteresis is removed in examination.Test shown in " No.1 " therein～" No.4 " is all judged to "None" magnetic hysteresis removal effect.Only " No.5 " institute
The test shown becomes " having " magnetic hysteresis removal effect.
Fig. 7 (B): then, current value is set as 100mA, makes the frequency of alternating current change to 11kHz～17kHz
Carry out the test of each time (No.1～No.7).Here the electric current virtual value suitable with magnetic hysteresis is 44.8mA.As a result, at all times
Middle Voffset is stable at stable value (2.499V), magnetic hysteresis removal effect all " having ".
Fig. 8 (A): the frequency setting alternating current is reduced to 500Hz, utilizes the current value shown in each time (No.1～No.4)
Attempt removing magnetic hysteresis.Here the electric current virtual value suitable with magnetic hysteresis is 112mA.As a result, in all times, Voffset becomes
Exceeding the value (2.490V) of permissible range, magnetic hysteresis removal effect is judged to "None".
Fig. 8 (B): be the 1kHz higher than Fig. 8 (A) by the frequency setting of alternating current, utilizes each (No.1～No.4) institute
The current value shown is attempted removing magnetic hysteresis.Here the electric current virtual value suitable with magnetic hysteresis is 112mA.But the most also it is all
Secondary middle Voffset becomes the value (2.490V) exceeding permissible range, it is determined that magnetic hysteresis removal effect is all judged to "None".
[summary (3) of result of the test]
According to using the result of the test of amperometric 100 of servo type, situation that can be clearly following.
(i) in Fig. 7 (A), magnetic hysteresis removal effect be the lower limit of the frequency of " having " be 8kHz.Though being not particularly illustrated, but by
The result carrying out other test understands, when the frequency of the alternating current applied is less than 8kHz, because high impedance is so can not obtain
Obtain sufficient magnetic hysteresis removal effect.
(ii) it addition, in Fig. 7 (B), magnetic hysteresis removal effect be the frequency of " having " be 11kHz～17kHz.Though scheming the most especially
Show, but from carrying out the result of other test, when frequency is higher than 17kHz, magnetic material core 102 carries out work as ACCT
Make, because servo action stops, so sufficient magnetic hysteresis removal effect can not be obtained.
(iii) thus, the scope of the optimum frequency of alternating current is 8kHz～17kHz, the frequency pair in the range of with this
When demagnetization coil 156 applies the alternating current with attenuation characteristic, can be at Ts die-away time suitably set as an example
(50ms) complete magnetic hysteresis in remove.Additionally because magnetic hysteresis removal effect can be confirmed and at Fig. 7 with frequency 10kHz in Figure 5
(B) magnetic hysteresis removal effect can be confirmed with the scope of 11kHz～17kHz in, so can be described as having in 10kHz～17kHz
More can be suitable for removing the effect of magnetic hysteresis.
Additionally, according to the result of other not shown test, die-away time, Ts can be set in the scope of 5ms～1000ms
In.Its reason is, when die-away time Ts than 5ms more in short-term, it is impossible to obtain sufficient magnetic hysteresis removal effect, when die-away time Ts exceed
During 1000ms, the responsiveness (starting the time) during system start-up is produced baneful influence.
Because die-away time is the longest, the time of demagnetization is the longest, so it is high to can be described as effect, but needs to consider above-mentioned evil
Bad impact.Therefore, there is no need to become the die-away time longer than above-mentioned Ts, die-away time can be 5ms～100ms, the most permissible
Become the time short as 5ms～50ms.Even if also being able to obtain erasure effect fully in 5ms～50ms.
[the 2nd embodiment]
Fig. 9 is the skeleton diagram of the structure of the amperometric 200 illustrating the 2nd embodiment.Additionally, herein in relation to the 1st
The item that embodiment is common, all marks common symbol including illustrating, and omits its explanation repeated.Hereinafter, will be real with the 1st
The difference executing mode illustrates the amperometric 200 of the 2nd embodiment as center.
In the 2nd embodiment, magnetic material core 102 not being wound around demagnetization coil, degaussing circuit 150 is via electric capacity
158 are connected in parallel with Secondary Winding 104.Therefore, in the 2nd embodiment, it is possible to be used for Secondary Winding 104 removing magnetic hysteresis
Purposes, and can correspondingly reduce winding usage amount.
In the 2nd embodiment, degaussing circuit 150 is attached with feedback coil 104 via electric capacity 158, works as utilization
This AC signal current/voltage by feedback system is made after the magnetic hysteresis of the AC signal removal magnetic material core 102 of demagnetization
During conversion precision resister, directly can observe the value of the outlet side of amperometric 200, but here, make feedback coil 104
Also serve as anti-magnetized coil function and magnetic material core 102 is carried out demagnetization, thus enable that amperometric 200 becomes and connect
Logical, first carry out the action of demagnetization, then carry out the action as amperometric 200.Therefore, do not carry out within the erasing time
Signal as amperometric 200 exports (output of current detection value).Additionally, as electric capacity 158, static capacity can be used
It is 50nF～the electric capacity of 0.22 μ F.
Other special circuit 108 or the structure of feedback circuit are identical with above-mentioned 1st embodiment, omit it here and say
Bright.
[the 3rd embodiment]
Figure 10 is the skeleton diagram of the structure of the amperometric 300 illustrating the 3rd embodiment.The most also be about with the 1st,
The item that 2nd embodiment is common, all marks common symbol including illustrating, and omits repeated explanation.Hereinafter, will be with
1, the difference of the 2nd embodiment illustrates the amperometric 300 of the 3rd embodiment as center.
[opening]
That is, the difference of the amperometric 300 of the 3rd embodiment is to become the style of opening without Secondary Winding.The
The amperometric 300 replacement special circuit 108 of 3 embodiments, has amplifying circuit 308, from the signal of Hall element 106
It is amplified via amplifying circuit 308, becomes voltage output (Vout).
Even if in the amperometric 300 of such style of opening, it is also possible to offseted by the frequency with 8kHz～17kHz
Magnetic coil 156 applies alternating current, comes with the 1st, carries out magnetic hysteresis removal in the same manner as the 2nd embodiment.
[action control example]
Then, the preference of the action control of the amperometric 100,200,300 of each embodiment is described.
In the 1st～the 3rd embodiment, amperometric 100,200,300 can be (the coldest by the system being suitable for respectively
Freeze machine) moment (during startup) of being turned on from off state of power supply as starting point, start to remove the action of magnetic hysteresis.
[the 1st, the control example of the 2nd embodiment]
Specifically, the 1st, the control example of the 2nd embodiment becomes following such structure, when examining applied current
Survey the system of device 100,200 when putting into (turn off → connect) power supply so that it is as trigger (trigger) from special circuit 108 to
Degaussing circuit 150 output action signal.Then, degaussing circuit 150 accepts this signal and starts to apply alternating current, and is controlling journey
Sequence is previously charged into die-away time complete in Ts remove magnetic hysteresis step.After, because via demagnetization in the work of system
Electric current with coil 156 can decay to the approximation of 0, so not having demagnetization coil 156 to make magnetic material core 102 produce magnetic flux
Situation.
[the control example of the 3rd embodiment]
It addition, the control example of the 3rd embodiment is following such structure, when the correspondence system of amperometric 300
When putting into (turn off → connect) power supply, as triggering from amplifying circuit 308 to degaussing circuit 150 output action signal.Disappear
Magnetic circuit 150 accepts this signal and starts to apply alternating current, completes in being enclosed in Ts die-away time the most in a control program
Remove the step of magnetic hysteresis.After, because the approximation of 0 can be decayed to via the electric current of demagnetization coil 156 in the work of system
Value, so not having demagnetization coil 156 to make magnetic material core 102 produce the situation of magnetic flux.
According to above-mentioned each embodiment, by being removed the dynamic of magnetic hysteresis when magnetic hysteresis affects the most significant system start-up
Make, at the beginning of the work of system starts, just can carry out the detection of electric current accurately.
The present invention is not restricted by above-mentioned embodiment, can carry out implementing later of various deformation.Such as, magnetic magnetic
The shape of core 102 is not only the four side ring shapes enumerated in each embodiment, it is also possible to be other polygon ring-shaped, or
Person can be toroidal or elliptical shape.It addition, magnetic material core 102 can use magnetic material (the ferrum oxygen beyond permalloy
Body (ferrite), silicon steel plate, Fe-Ni alloy etc.) make, circular structure or layer can be used in magnetic material core 102
Folded structure.Additionally, the specification of the concrete shape of magnetic material core 102, size or thickness etc. can tested with really as object
The characteristic surveying electric current the most suitably changes.
It addition, the amperometric 100,200,300 enumerated together with diagram or one part structure are only preferred one
Example, though basic structure is added various key element or displacement a part also be able to be appropriately carried out the present invention be self-evident
's.
Claims (7)
1. an amperometric, possesses:
Magnetic material core, its configuring with ring-type around direction along the magnetic field produced when sensed current turns on,
The gap of configuration magnetic detecting element it is formed with in a part；And
Degaussing circuit, it is by having predetermined to the winding being arranged at described magnetic material core with the frequency applying in preset range
The alternating current of attenuation characteristic, eliminate the magnetic flux of residual in described magnetic material core.
Amperometric the most according to claim 1, it is characterised in that
Described degaussing circuit applies described alternating current with the frequency in the range of 8kHz to 17kHz.
Amperometric the most according to claim 2, it is characterised in that
Described alternating current is applied with the described frequency in the range of 10kHz to 17kHz.
4. according to the amperometric described in any one in claims 1 to 3, it is characterised in that
Described degaussing circuit applies as described predetermined attenuation characteristic, and die-away time is the institute in the range of 5ms to 1000ms
State alternating current.
Amperometric the most according to claim 4, it is characterised in that
Applying described die-away time is the described alternating current in the range of 5ms to 50ms.
Amperometric the most as claimed in any of claims 1 to 5, it is characterised in that
Being also equipped with feedback circuit, this feedback circuit, according to the signal exported from described magnetic detecting element, makes feedback current be wound around
Turn in the Secondary Winding of described magnetic material core,
Described degaussing circuit applies described alternating current for the Secondary Winding of described feedback circuit.
Amperometric the most as claimed in any of claims 1 to 6, it is characterised in that
Described degaussing circuit, from the moment of the conducting starting described sensed current, starts to apply described alternating current.
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| JP2015-068510 | 2015-03-30 | ||
| JP2015068510A JP6200445B2 (en) | 2015-03-30 | 2015-03-30 | Current detector |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110873818A (en) * | 2018-08-31 | 2020-03-10 | 株式会社田村制作所 | Current detector |
| CN111999541A (en) * | 2020-09-10 | 2020-11-27 | 秦孝文 | Anti-magnetic disturbance integrated nondestructive current detection high-precision intelligent sensor probe |
| CN112965448A (en) * | 2021-02-01 | 2021-06-15 | 青岛黄海学院 | Electric automatization management control system and device |
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| EP3812785A1 (en) * | 2019-10-22 | 2021-04-28 | LEM International SA | Fluxgate current transducer |
| KR102435583B1 (en) * | 2021-01-19 | 2022-08-24 | 숭실대학교 산학협력단 | Magnetic field type current sensor manufactured with Carbon nanotube wire |
| WO2022249708A1 (en) * | 2021-05-24 | 2022-12-01 | 日置電機株式会社 | Signal injection device and impedance measurement device |
| WO2022249709A1 (en) * | 2021-05-24 | 2022-12-01 | 日置電機株式会社 | Impedance measurement device |
| US20240345137A1 (en) * | 2023-04-14 | 2024-10-17 | Fluke Corporation | Non-contact dc current measurement device with open loop degaussing |
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| Publication number | Publication date |
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| JP2016188790A (en) | 2016-11-04 |
| CN106018915B (en) | 2019-11-29 |
| JP6200445B2 (en) | 2017-09-20 |
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