CN103983835A - Direct current small-current transformer and method for measuring current of direct current small-current transformer - Google Patents
Direct current small-current transformer and method for measuring current of direct current small-current transformer Download PDFInfo
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- CN103983835A CN103983835A CN201410216037.8A CN201410216037A CN103983835A CN 103983835 A CN103983835 A CN 103983835A CN 201410216037 A CN201410216037 A CN 201410216037A CN 103983835 A CN103983835 A CN 103983835A
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Abstract
The invention discloses a direct current small-current transformer which comprises an annular magnetic iron core allowing a direct current small-current wire to penetrate and surrounded by a winding. The winding is connected with a waveform generator. The waveform generator is connected with a single-chip microcomputer and comprises a first circuit, a second circuit and a comparer, wherein the first circuit and the second circuit are connected in parallel and connected with a power source. The two ends of the winding are connected to the first circuit. The first measurement end of the comparer is connected to the first circuit and the second measurement end of the comparer is connected to the second circuit. The comparer can measure the specific value of data through the first measurement end and the second measurement end, so that the current direction of the power source is changed, the waveform generator generates waves with a certain duty ratio, the waves generated by the waveform generator are received by the single-chip microcomputer, and the volume of the current inside the direct current small-current wire is obtained through change of the duty ratio of the waves. The direct current small-current transformer has the advantages of being small in size, high in accuracy, simple in interface, convenient to install and novel in detection method.
Description
Technical field
The present invention relates to the technical field of power measurement, relate in particular to a kind of method of DC low current mutual inductor and measurement electric current thereof.
Background technology
In straight-flow system, DC leakage current sensor is an indispensable Important Components; DC leakage-current for equipment detects; be widely used in the industry equipment such as direct current transportation, electric power storage detection, direct current cabinet, power supply, large-scale health care equipment, photovoltaic, wind-power electricity generation, communication base station; the very first time feeds back the electric leakage situation of equipment; the original papers such as the earth leakage protection of rear end can be taken measures on customs clearance in the very first time; avoid accident to occur, safe handling, production operation.
Tradition is used the method for shunt and transmitter, and this method is not once isolated with secondary, have larger potential safety hazard, and precision is not high.
Summary of the invention
Technical matters to be solved by this invention is for the above-mentioned state of the art, and a kind of volume is little, precision is high, interface is simple, easy for installation, detection method is novel DC low current mutual inductor is provided and measures the method for electric current.
The present invention solves the problems of the technologies described above adopted technical scheme:
A kind of DC low current mutual inductor, comprise the annular magnet iron core that is surrounded with coiling group that can be passed by DC low current electric wire, wherein, coiling group connects waveform generator, waveform generator is connected with single-chip microcomputer, waveform generator includes the first loop and second servo loop and the comparer that are arranged in parallel, the first loop is connected with power supply with second servo loop, the first loop is accessed at the two ends of coiling group, the first measuring junction of comparer accesses the first loop, the second measuring junction access second servo loop of comparer, comparer can make waveform generator produce the ripple with certain dutycycle by the direction of current of the ratio change power supply of the first measuring junction and the second measuring junction data measured, single-chip microcomputer receives the ripple of waveform generator generation and obtains size of current in DC low current electric wire by the change in duty cycle of ripple.
For optimizing technique scheme, the concrete measure of taking also comprises:
Above-mentioned power supply includes external malleation single supply interface and can produce the vacuum generator of negative voltage.
Above-mentioned vacuum generator includes negative pressure and produces electric capacity and produce with negative pressure the charge-discharge circuit that electric capacity is connected, and charge-discharge circuit is connected with single-chip microcomputer, and single-chip microcomputer discharges the square-wave voltage with certain dutycycle to charge-discharge circuit.
Above-mentioned external malleation single supply interface accesses waveform generator after by transformer transformation, external malleation single supply interface input voltage is+12V, external malleation single supply interface is+5V that the voltage of vacuum generator output is-5V by input voltage after transformer transformation.
The first above-mentioned loop includes the first resistance, the second resistance, coiling group and the 3rd resistance that series connection arranges, second servo loop comprises the 4th resistance, the 5th resistance and the 3rd resistance that series connection arranges, the first measuring junction is measured the voltage at the first resistance two ends, the second measuring junction is measured the voltage at the 4th resistance two ends, and single-chip microcomputer receives the voltage wave that the 3rd resistance two ends produce.
Above-mentioned DC low current mutual inductor includes four external terminals, is respectively RS485A terminal, RS485B terminal, GND terminal and external malleation single supply interface.
Above-mentioned single-chip microcomputer is provided with communication output terminal.
The invention also discloses a kind of DC low current mutual inductor and measure the method for electric current, comprise the following steps:
Step 1, it is 0mA that the DC current of passing in annular magnet iron core is set, in the time that the first loop current is stablized, the absolute value of voltage at the first resistance two ends is greater than the absolute value of voltage at the 4th resistance two ends, set the voltage at voltage-tetra-resistance two ends at value m=first resistance two ends, when m value is timing, the voltage of comparer control power supply output is negative voltage, when m value is when negative, the voltage of comparer control power supply output is positive voltage, in the first loop, be connected to coiling group, coiling group makes the Voltage Establishment of the first resistance slow compared with the Voltage Establishment of the 4th resistance as inductance, the positive and negative voltage square wave that alternately makes the 3rd resistance two ends produce certain dutycycle of m value, this square wave coverlet sheet machine receives and calculates this duty cycle square wave, duty cycle square wave is designated as X,
Step 2, by DC low current electric wire through annular magnet iron core, electric current in DC low current electric wire changes the magnetic flux of annular magnet iron core, the inductance value of coiling group also changes thereupon, the Voltage Establishment speed of the first resistance and the inductance value variable quantity of coiling group are inversely proportional to, and the voltage square wave dutycycle that the 3rd resistance two ends produce is designated as Y;
The magnitude of current that step 3, single-chip microcomputer calculate in DC low current electric wire is n (Y-X)+b, and wherein n is that monolithic is concentrated the scale-up factor of depositing, and b is zero correction coefficient.
When m value is timing, the voltage of power supply output be-5V, and when m value is when bearing, the voltage that power supply is exported is 5V.
Compared with prior art, DC low current mutual inductor of the present invention, comprise the annular magnet iron core that is surrounded with coiling group that can be passed by DC low current electric wire, wherein, coiling group connects waveform generator, waveform generator is connected with single-chip microcomputer, waveform generator includes the first loop and second servo loop and the comparer that are arranged in parallel, the first loop is connected with power supply with second servo loop, the first loop is accessed at the two ends of coiling group, the first measuring junction of comparer accesses the first loop, the second measuring junction access second servo loop of comparer, comparer can make waveform generator produce the ripple with certain dutycycle by the direction of current of the ratio change power supply of the first measuring junction and the second measuring junction data measured, single-chip microcomputer receives the ripple of waveform generator generation and obtains size of current in DC low current electric wire by the dutycycle of ripple.The present invention has utilized in the time of direct current input ring-shaped magnet and can make the magnetic flux of ring-shaped magnet change, cause characteristics design that coiling group inductance value changes corresponding square wave produce loop, the dutycycle of square wave is relevant to coiling group inductance value, Single Chip Microcomputer (SCM) system just can be known coiling group inductance value by the dutycycle of measuring square wave, further draws the galvanic size of current by ring-shaped magnet.Circuit of the present invention is all made up of device simple and that power consumption is little, therefore only need equipment oneself to produce a low power negative voltage, positive voltage is provided by external power supply.Vacuum generator produces electric capacity by negative pressure and charge-discharge circuit forms, charge-discharge circuit input end is connected with SCM PWM output terminal, single-chip microcomputer discharges PWM square wave to charge-discharge circuit, in the time that voltage enters, negative pressure produces capacitor charging, in the time of loss of voltage, negative pressure produces electric capacity and outwards discharges, single-chip microcomputer ensures that negative pressure produces electric capacity electric weight and discharges before charging again, the principle that can not suddenly change due to capacitance voltage makes negative pressure generation capacitor discharge voltage remain a definite value, and the capacity that the watt level of vacuum generator produces electric capacity by negative pressure determines.Waveform generator of the present invention comprises two circuit that are arranged in parallel and can measure the comparer that compares the first resistance and the 4th resistive voltage, comparer changes the direction of current of power supply according to the voltage difference of the first resistance and the 4th resistance, object is to produce a square wave with certain dutycycle, and the dutycycle of this square wave is subject to the impact of coiling group inductance value, can accurately measure by dutycycle thus the size of the DC current that affects coiling group inductance value.
The present invention has advantages of that volume is little, precision is high, interface is simple, easy for installation, detection method is novel.
Brief description of the drawings
Fig. 1 is structural representation of the present invention;
Fig. 2 is the structural representation of vacuum generator;
Fig. 3 is the circuit diagram of waveform generator;
Fig. 4 is magnetive cord magnetic field intensity of the present invention and magnetization matched curve.
Embodiment
Below in conjunction with accompanying drawing, embodiments of the invention are described in further detail.
Fig. 1 is to Figure 4 shows that structural representation of the present invention.
Reference numeral is wherein: annular magnet iron core 1, coiling group 11, DC low current electric wire 2, waveform generator 3, the first resistance 3a, the second resistance 3b, the 3rd resistance 3c, the 4th resistance 3d, the 5th resistance 3e, the first loop 31, second servo loop 32, comparer 33, the first measuring junction 33a, the second measuring junction 33b, power supply 34, single-chip microcomputer 4, vacuum generator 5, negative pressure produce electric capacity 51, charge-discharge circuit 52.
As shown in Figure 1 to Figure 3, a kind of DC low current mutual inductor of the present invention, comprise the annular magnet iron core 1 that is surrounded with coiling group 11 that can be passed by DC low current electric wire 2, wherein, coiling group 11 connects waveform generator 3, waveform generator 3 is connected with single-chip microcomputer 4, waveform generator 3 includes the first loop 31 and second servo loop 32 and the comparer 33 that are arranged in parallel, the first loop 31 is connected with power supply 34 with second servo loop 32, the first loop 31 is accessed at the two ends of coiling group 11, the first measuring junction 33a of comparer 33 accesses the first loop 31, the second measuring junction 33b access second servo loop 32 of comparer 33, comparer 33 can make waveform generator 3 produce the ripple with certain dutycycle by the direction of current of the ratio change power supply 34 of the first measuring junction 33a and the second measuring junction 33b data measured, single-chip microcomputer 4 receives the ripple that waveform generator 3 produces and obtains the interior size of current of DC low current electric wire 2 by the change in duty cycle of ripple.
In embodiment, power supply 34 includes external malleation single supply interface and can produce the vacuum generator 5 of negative voltage.
In embodiment, vacuum generator 5 includes negative pressure and produces electric capacity 51 and produce with negative pressure the charge-discharge circuit 52 that electric capacity 51 is connected, and charge-discharge circuit 52 is connected with single-chip microcomputer 4, and single-chip microcomputer 4 discharges the square-wave voltage with certain dutycycle to charge-discharge circuit 52.
In embodiment, external malleation single supply interface accesses waveform generator 3 after by transformer transformation, external malleation single supply interface input voltage is+12V that external malleation single supply interface is+5V that the voltage that vacuum generator 5 is exported is-5V by input voltage after transformer transformation.
In embodiment, the first loop 31 includes the first resistance 3a, the second resistance 3b, coiling group 11 and the 3rd resistance 3c that series connection arranges, second servo loop 32 comprises the 4th resistance 3d, the 5th resistance 3e and the 3rd resistance 3c that series connection arranges, the first measuring junction 33a measures the voltage at the first resistance 3a two ends, the second measuring junction 33b measures the voltage at the 4th resistance 3d two ends, and single-chip microcomputer 4 receives the voltage wave that the 3rd resistance 3c two ends produce.
In embodiment, DC low current mutual inductor includes four external terminals, is respectively RS485A terminal, RS485B terminal, GND terminal and external malleation single supply interface.
In embodiment, single-chip microcomputer 4 is provided with communication output terminal.
The invention also discloses a kind of DC low current mutual inductor and measure the method for electric current, comprise the following steps:
Step 1, it is 0mA that the DC current of passing in annular magnet iron core 1 is set, in the time of the first loop 31 current stabilization, the absolute value of voltage at the first resistance 3a two ends is greater than the absolute value of voltage at the 4th resistance 3d two ends, set the voltage at voltage-tetra-resistance 3d two ends at value m=first resistance 3a two ends, when m value is timing, it is negative voltage that comparer 33 is controlled the voltage that power supply 34 exports, when m value is when negative, it is positive voltage that comparer 33 is controlled the voltage that power supply 34 exports, in the first loop 31, be connected to coiling group 11, coiling group 11 makes the Voltage Establishment of the first resistance 3a slow compared with the Voltage Establishment of the 4th resistance 3d as inductance, the positive and negative voltage square wave that alternately makes the 3rd resistance 3c two ends produce certain dutycycle of m value, this square wave coverlet sheet machine 4 receives and calculates this duty cycle square wave, duty cycle square wave is designated as X,
Step 2, by DC low current electric wire 2 through annular magnet iron core 1, electric current in DC low current electric wire 2 changes the magnetic flux of annular magnet iron core 1, the inductance value of coiling group 11 also changes thereupon, the Voltage Establishment speed of the first resistance 3a and the inductance value variable quantity of coiling group 11 are inversely proportional to, and the voltage square wave dutycycle that the 3rd resistance 3c two ends produce is designated as Y;
The magnitude of current that step 3, single-chip microcomputer 4 calculate in DC low current electric wire 2 is n (Y-X)+b, and wherein n is that monolithic is concentrated the scale-up factor of depositing, and b is zero correction coefficient.
When m value is timing, the voltage that power supply 34 is exported is-5V, and when m value is when bearing, the voltage that power supply 34 is exported is 5V.
The present invention has utilized in the time of direct current input ring-shaped magnet and can make the magnetic flux of ring-shaped magnet change, cause characteristics design that coiling group inductance value changes corresponding square wave produce loop, the dutycycle of square wave is relevant to coiling group inductance value, Single Chip Microcomputer (SCM) system just can be known coiling group inductance value by the dutycycle of measuring square wave, further draws the galvanic size of current by ring-shaped magnet.
The present invention organizes 11 windings on annular magnet iron core 1 by coiling, the first circuit of 11 two ends access waveform generators 3 is organized in coiling, the first measuring junction 33a of comparer 33 measures the voltage at the first resistance 3a two ends, the second measuring junction 33b measures the voltage at the 4th resistance 3d two ends, single-chip microcomputer 4 receives the voltage wave that the 3rd resistance 3c two ends produce, single-chip microcomputer 4 produces the square-wave voltage with certain dutycycle, negative pressure is produced to electric capacity 51 and carry out the charging of certain dutycycle, negative pressure produces export-5V of electric capacity 51 voltage.The positive electricity output terminals A of external 5V positive supply composition power supply 34, negative pressure produces the negative electricity output terminal B that electric capacity 51 forms power supply 34, after circuit assembles, reference wave dutycycle is first set, it is the ripple dutycycle that while not having electric current to pass through in annular magnet iron core 1, single-chip microcomputer 4 receives, the absolute value of voltage that the first resistance 3a two ends in the time of the first loop 31 current stabilization are first set is greater than the absolute value of voltage at the 4th resistance 3d two ends, for example, in the time of the first loop 31 current stabilization the first resistance 3a can assign to 3V voltage and now the 4th resistance 3d can only assign to 2V, this can reach by debugging two resistance shared resistance deal in circuit separately.
Formula is absolute value of voltage=5V × the first resistance 3a resistance/(the first resistance 3a resistance+the second resistance 3b resistance+three resistance 3c resistance) at the first resistance 3a two ends;
Absolute value of voltage=5V × four resistance 3d resistance/(the 3rd resistance 3c resistance+four resistance 3d resistance+five resistance 3e resistance) at the 4th resistance 3d two ends;
Comparer 33 is set, in the time that the voltage at the first resistance 3a two ends is greater than the voltage at the 4th resistance 3d two ends, it is negative voltage that comparer 33 is controlled the voltage that power supply 34 exports, in the time that the voltage at the first resistance 3a two ends is less than the voltage at the 4th resistance 3d two ends, it is positive voltage that comparer 33 is controlled the voltage that power supply 34 exports, coiling group 11, as an inductance, makes the Voltage Establishment of the first resistance 3a slower, and the voltage wave that causes the 3rd resistance 3c two ends to produce is the square wave of certain dutycycle.This dutycycle is exactly reference wave dutycycle, is designated as X.
Then DC low current electric wire 2 is being passed to annular magnet iron core 1, electric current has changed the magnetic flux of annular magnet iron core 1, cause coiling group 11 to change on the electric current obstruction ability in the first loop 31: grow still dies down and is subject to the impact of direction of current, and the size of change degree is subject to the impact of strength of current.The speed of setting up voltage due to the first resistance 3a changes, and causes the voltage square wave dutycycle that the 3rd resistance 3c two ends produce to change, and the dutycycle of this change is designated as Y;
Finally, single-chip microcomputer 4 calculates the value of Y-X, and the magnitude of current in DC low current electric wire 2 is n (Y-X)+b, and wherein n is that monolithic is concentrated the scale-up factor of depositing, and b is zero correction coefficient.
For example we remember that the first resistance 3a is RA1, the second resistance 3b is RA2, the 3rd resistance 3c is RA3, the 4th resistance 3d is RA4, the 5th resistance 3e is RA5, the first resistance 3a both end voltage is V1, the 4th resistance 3d both end voltage is V2, the voltage that the 3rd resistance 3c and the 4th resistance 3d get is altogether V5, make RA1=200 ohm, RA2=100 ohm, RA4=100 ohm, RA5=200 ohm, V1=2/3*V5 when the first loop 31 current stabilization, V2=1/3*V5, it vibrates as shown in Figure 5, in figure, solid line is V1 voltage change process, dotted line is V2 change in voltage, process is as follows: in figure, S1 is original state: original state supply voltage at random for 5V or-5V, we illustrate oscillatory process with 5V herein, when-5V, there is similar process.Now V1>V2, power supply is exported negative voltage at once, therefore V2 place sets up negative voltage 1/3*V5 at once, and because the V1 voltage that exists of inductance slowly declines to negative steady state voltage 2/3*V5, when V1 voltage drops to (S2) while being less than V2 voltage, power supply is exported positive voltage at once, now V2 place sets up positive voltage 1/3*V5 at once, V1 voltage slowly rises to positive steady state voltage 2/3*V5, when V1 voltage rises to (S3) while being greater than V2 voltage, power supply is exported negative voltage at once, now V2 place sets up negative voltage 1/3*V5 at once, V1 voltage slowly declines to negative steady state voltage 2/3*V5, produce thus the square wave of certain frequency at V5 place.
As shown in Figure 4, be magnetive cord magnetic field intensity (H) and the magnetization (B) matched curve.In coiling group 11, the larger magnetic field intensity of electric current is larger.In the time that DC current is 0, BH curve is P, and visible BH curve is about origin symmetry, thus the positive voltage of the first resistance 3a equate Time Created with negative voltage Time Created, establishing the now Voltage-output duty cycle square wave of the 3rd resistance 3c is 50%.In the time that DC current is greater than 0, BH curve moves left to P2, in the time that DC current is less than 0, BH curve is shifted to the right to P1, now the first resistance 3a positive voltage is just different Time Created from negative voltage Time Created, thus the Voltage-output duty cycle square wave of the 3rd resistance 3c be not 50% and equal proportion change (because BH curve is linear near initial point), but concrete dutycycle is increase or reduce to depend on that coiling organizes 11 Same Name of Ends directions, in the time that Same Name of Ends is fixing, the change direction of dutycycle has also just been determined.
Single-chip microcomputer 4 adopts communication modes, can be integrated with dcs (DCS) very easily, be convenient to safeguard search problem, and reduce installation and maintenance expense.
Below be only the preferred embodiment of the present invention, protection scope of the present invention is also not only confined to above-described embodiment, and all technical schemes belonging under thinking of the present invention all belong to protection scope of the present invention.It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principles of the present invention, should be considered as protection scope of the present invention.
Claims (9)
1. a DC low current mutual inductor, comprise the annular magnet iron core (1) that is surrounded with coiling group (11) that can be passed by DC low current electric wire (2), it is characterized in that: described coiling group (11) connects waveform generator (3), described waveform generator (3) is connected with single-chip microcomputer (4), described waveform generator (3) includes the first loop (31) and second servo loop (32) and the comparer (33) that are arranged in parallel, described the first loop (31) is connected with power supply (34) with second servo loop (32), the first loop (31) is accessed at the two ends of described coiling group (11), the first measuring junction (33a) access first loop (31) of described comparer (33), the second measuring junction (33b) access second servo loop (32) of described comparer (33), described comparer (33) can make waveform generator (3) produce the ripple with certain dutycycle by the first measuring junction (33a) and the direction of current of the ratio change power supply (34) of the second measuring junction (33b) data measured, described single-chip microcomputer (4) receives the ripple of waveform generator (3) generation and obtains the interior size of current of DC low current electric wire (2) by the change in duty cycle of ripple.
2. a kind of DC low current mutual inductor according to claim 1, is characterized in that: described power supply (34) includes external malleation single supply interface and can produce the vacuum generator (5) of negative voltage.
3. a kind of DC low current mutual inductor according to claim 2, it is characterized in that: described vacuum generator (5) includes negative pressure and produces electric capacity (51) and produce with negative pressure the charge-discharge circuit (52) that electric capacity (51) is connected, described charge-discharge circuit (52) is connected with single-chip microcomputer (4), and described single-chip microcomputer (4) discharges the square-wave voltage with certain dutycycle to charge-discharge circuit (52).
4. a kind of DC low current mutual inductor according to claim 3, it is characterized in that: described external malleation single supply interface accesses waveform generator (3) after by transformer transformation, described external malleation single supply interface input voltage is+12V, external malleation single supply interface is+5V that the voltage of described vacuum generator (5) output is-5V by input voltage after transformer transformation.
5. a kind of DC low current mutual inductor according to claim 4, it is characterized in that: described the first loop (31) includes the first resistance (3a) that series connection arranges, the second resistance (3b), coiling group (11) and the 3rd resistance (3c), described second servo loop (32) comprises the 4th resistance (3d) that series connection arranges, the 5th resistance (3e) and the 3rd resistance (3c), described the first measuring junction (33a) is measured the voltage at the first resistance (3a) two ends, described the second measuring junction (33b) is measured the voltage at the 4th resistance (3d) two ends, described single-chip microcomputer (4) receives the voltage wave that the 3rd resistance (3c) two ends produce.
6. a kind of DC low current mutual inductor according to claim 5, is characterized in that: described DC low current mutual inductor includes four external terminals, is respectively RS485A terminal, RS485B terminal, GND terminal and described external malleation single supply interface.
7. a kind of DC low current mutual inductor according to claim 6, is characterized in that: described single-chip microcomputer (4) is provided with communication output terminal.
8. DC low current mutual inductor as claimed in claim 5 is measured a method for electric current, it is characterized in that: comprise the following steps:
Step 1, it is 0mA that the DC current of passing in annular magnet iron core (1) is set, in the time of the current stabilization of the first loop (31), the absolute value of voltage at the first resistance (3a) two ends is greater than the absolute value of voltage at the 4th resistance (3d) two ends, set the voltage at voltage-tetra-resistance (3d) two ends at value m=the first resistance (3a) two ends, when m value is timing, the voltage that comparer (33) is controlled power supply (34) output is negative voltage, when m value is when negative, the voltage that comparer (33) is controlled power supply (34) output is positive voltage, in the first loop (31), be connected to coiling group (11), coiling group (11) makes the Voltage Establishment of the first resistance (3a) slow compared with the Voltage Establishment of the 4th resistance (3d) as inductance, the positive and negative voltage square wave that alternately makes the 3rd resistance (3c) two ends produce certain dutycycle of m value, this square wave coverlet sheet machine (4) receives and calculates this duty cycle square wave, duty cycle square wave is designated as X,
Step 2, by DC low current electric wire (2) through annular magnet iron core (1), electric current in DC low current electric wire (2) changes the magnetic flux of annular magnet iron core (1), the inductance value of coiling group (11) also changes thereupon, the inductance value variable quantity of the Voltage Establishment speed of the first resistance (3a) and coiling group (11) is inversely proportional to, and the voltage square wave dutycycle that the 3rd resistance (3c) two ends produce is designated as Y;
The magnitude of current that step 3, single-chip microcomputer (4) calculate in DC low current electric wire (2) is n (Y-X)+b, and wherein n is that monolithic is concentrated the scale-up factor of depositing, and b is zero correction coefficient.
9. DC low current mutual inductor according to claim 7 is measured the method for electric current, it is characterized in that: described when m value be timing, the voltage of power supply (34) output be-5V, when m value is while bearing, the voltage that power supply (34) is exported is 5V.
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| CN104374982A (en) * | 2014-07-25 | 2015-02-25 | 中国计量科学研究院 | Non-contact direct current measuring circuit and method |
| CN110412334A (en) * | 2019-06-19 | 2019-11-05 | 中国人民解放军海军工程大学 | A kind of digital Zero flux leakage current sensor |
| CN110412327A (en) * | 2019-06-19 | 2019-11-05 | 中国人民解放军海军工程大学 | A kind of digital direct current current sensor |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104374982A (en) * | 2014-07-25 | 2015-02-25 | 中国计量科学研究院 | Non-contact direct current measuring circuit and method |
| CN110412334A (en) * | 2019-06-19 | 2019-11-05 | 中国人民解放军海军工程大学 | A kind of digital Zero flux leakage current sensor |
| CN110412327A (en) * | 2019-06-19 | 2019-11-05 | 中国人民解放军海军工程大学 | A kind of digital direct current current sensor |
| CN110412327B (en) * | 2019-06-19 | 2022-02-18 | 中国人民解放军海军工程大学 | Digital direct current sensor |
| CN110412334B (en) * | 2019-06-19 | 2022-02-18 | 中国人民解放军海军工程大学 | Digital zero-flux leakage current sensor |
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Application publication date: 20140813 |