CN202041573U - A pulse current sensor - Google Patents

Abstract

The utility model discloses a pulse current sensor, which comprises a coil and a non-inductive precise resistor, wherein the non-inductive precise resistor is connected in series with a coil outlet, and in addition, the resistance of the non-inductive precise resistor is matched with the coil turn number. A non-magnetic-core semicircular hollow structure is adopted, during the measurement, the sensor per se and a current loop to be measured do not have the direct electric connection, and the electromagnetic field coupling is adopted, so the pulse current sensor and the main loop have a good electric insulation effect. Because the magnetic core saturation problem does not exist, the measurement range is wide, the current measurement range can be from several amperes to several hundred thousand amperes, the frequency range is between 0.1MHz and 100MHz, the measurement precision can reach 0.1 percent, the size is small, the weight is light, and a good device is provided for the pulse current measurement with heavy current and high efficiency such as lightning current and the like.

Description

A kind of pulses of current sensor

Technical field

The utility model belongs to the electrical engineering technical field.Be particularly related to a kind of pulses of current sensor.

Background technology

The sensor that is used for Super-Current Measurement at present, with regard to its principle of work, mainly be divided into two big classes: the first kind is a direct method, promptly land to determine the size of tested electric current according to the voltage of tested electric current on the known resistance shunt, another kind of is indirect method, it is the magnetic field of being set up based on tested electric current, measures the measuring task that methods such as its magnetic field intensity, magnetic flux are finished big electric current indirectly by other means, is characterized in that the problems of measurement with electric current changes the problems of measurement in magnetic field into.

When adopting first method to measure, when shunt is measured big electric current, self temperature variation will cause its resistance value to change, because the thermal stress that temperature variation produces also can influence the resistance value of shunt, become the key factor that influences systematic measurement error simultaneously.In design, need to consider suitable connected mode,, can eliminate the influence of thermal stress as the flexible connection mode that generally adopts.In addition, when measuring pulse high current with shunt, except that will the inductance value of minimizing itself, very the more important be exactly to consider the influence of kelvin effect.

When adopting the second way to measure, measure coil itself and directly not electric the getting in touch of tested current return, but pass through electromagnetic field couples, therefore with major loop good electric insulation is arranged, owing to there is not the core sataration problem, measurement range is wide, same winding, and current measuring range can be from several amperes to hundreds of kilo-amperes; Wide frequency range generally can be designed into more than 0.1～100MHz the accuracy of measurement height, be easy to realize measuring digitizing, networking and robotization, can not produce danger such as inflammable, explosive with digital quantity output, compliance with environmental protection requirements, and volume is little, in light weight, production cost is low.

The utility model content

The purpose of this utility model is exactly the deficiency that exists at above-mentioned prior art, based on coil parameter cooperate from integral principle, provide a kind of installation simple and convenient, it is big to have a current measuring range, wide frequency range, the pulses of current sensor that accuracy is high.

The technical scheme that this novel practical provides is: a kind of pulses of current sensor comprises coil and is serially connected in the noninductive precision resistance that coil outlet and its resistance and coil turn are complementary.

As preferred version of the present utility model:

Described coil case is the non-closed shielding can that a vertical, horizontal is provided with opening.

Described coil is the individual layer coiling, and be serially connected with in its coil rack that a circle coiling direction is opposite with the spiral working direction, the outlet of winding and inlet be at the center of same end winding.

Described coil rack is square-section and two loop configuration that semicircle combines.

The resistance of described noninductive precision resistance≤1 Ω.

The utility model adopts passive from integral way, coil exports resistance in parallel and is not more than the noninductive precision resistance of 1 Ω, cooperates the coil turn matching Design, realizes passively exporting from the undistorted output measured pulse of integration electric current, has low-power output, advantage of simple structure.

Enameled wire is twined certain several circles equably on the uniform annular non-magnetic insulating material ring skeleton in square-section, coil turn, cross-sectional sizes realize that with current measurement range and measurement frequency band parameter cooperates.The cross section be rectangle the annular skeleton the loop construction synoptic diagram as shown in Figure 1, i₁Be (once) electric current in the current, c is the output voltage at coil two ends, and a, b be the interior external radius of annular skeleton respectively.

Passive self-integrating method is the output terminal that precision resistance R is connected on coil, utilizes the voltage at R two ends to reflect the requirement that the size and the waveform of tested primary current, the selection of R size should be taken into account measurement range, frequency band, cooperate from integral parameter.Equivalent circuit diagram as shown in Figure 2.

For eliminating the influence that axial disturbing magnetic field produces induced potential at big wire turn, portion in coil when coil is the individual layer coiling promptly in the skeleton, is connected in series a circle center winding, and the direction of coiling is opposite with the spiral working direction, the outlet of winding with enter the mouth at same end.For the ease of processing and on-the-spot the installation, coil rack has adopted square-section, two loop configuration that semicircle combines in design, as shown in Figure 3.

For reducing the interference of external electromagnetic field, coil case adopts in length and breadth and shields to opening, non-closed can, and coil adopts in length and breadth and shields to opening, non-closed masking foil, is convenient to can and exports the BNC connector single-point connect.

The utility model is mainly used in the measurement of some pulse currents such as lightning current, owing to adopt the semicircle hollow core structures of non-magnetic core, sensor itself and directly not electric the getting in touch of tested current return during measurement, but, therefore good electric insulation is arranged with major loop by electromagnetic field couples; Owing to there is not the core material saturation problem, measurement range is wide, current measuring range can from several amperes to hundreds of kilo-amperes, frequency range is in 0.1～100MHz; Accuracy of measurement can reach 0.1%, and volume is little, in light weight, for the high-frequency impulse current measurements of some big electric currents such as lightning current provide good device.

Description of drawings

Fig. 1 is a structure diagram of the present utility model;

Fig. 2 is measuring principle figure of the present utility model;

Fig. 3 is a winding diagram of the present utility model;

Embodiment

The utility model is described in further detail below in conjunction with the accompanying drawing illustrated embodiment:

As shown in Figure 1, coil is made of the N circle enameled wire that twines equably on the uniform non-magnetic insulating material ring skeleton in square-section.When the lead that is loaded with big electric current vertically passed its center, the variation sensing by the current surrounding magnetic field went out the voltage signal that can reflect tested size of current, and its principle of work is equivalent to a kind of current transformer.The current that is positioned at the center is equivalent to a winding of mutual inductor, and the N circle coil that is wrapped on the skeleton is its Secondary Winding.The cross section be rectangle the annular skeleton the loop construction synoptic diagram as shown in Figure 1, i₁Be (once) electric current in the current, c is the output voltage at coil two ends, a, and b is the interior external radius of annular skeleton respectively.

As shown in Figure 2, passive self-integrating method is the output terminal that noninductive precision resistance R is connected on coil, utilizes the voltage at R two ends to reflect the size and the phase place of tested primary current, and listing equation by Kirchhoff's law has:

u＝-Mdi₁/dt＝Ldi₂/dt+R_Li₂+Ri_r (1)

By preceding surface analysis 1/ ω C₀＞＞R, promptly ic ≈ 0, i_r≈ i₂, formula (1) becomes:

u＝-Mdi₁/dt＝Ldi₂/dt+(R_L+R)i₂ (2)

Work as resistance R_LWhen+R rate of change very little or electric current is very big, promptly ω L＞＞(R_L+ R), then formula (2) is rewritten as:

-Mdi₁/dt＝Ldi₂/dt (3)

The both sides integration promptly has:

i₂＝-Mi₁/L (4)

Under coil turn, cross section and the accurate mated condition of sampling resistor parameter, the voltage at sampling resistor two ends is:

$u_0=-{\mathrm{Ri}}_r\≈-{\mathrm{Ri}}_2=\frac{R}{N}{i}_1---\left(5\right)$

By following formula as can be known, the output voltage at sampling resistor two ends is directly proportional with the primary current amplitude, and phase place is identical, reaches by measuring output voltage u₀To measure input current i₁Purpose.

As shown in Figure 3, for eliminating the influence that axial disturbing magnetic field produces induced potential at big wire turn, portion in coil when coil is the individual layer coiling, be in the skeleton, be connected in series a circle center winding, the direction of coiling is opposite with the spiral working direction, and the outlet of winding and inlet are at same end.

For the ease of processing and on-the-spot the installation, coil rack has been selected the semi-round ring shape structure of square-section for use in design, be combined into a circular configuration by two semicircles in the practical application, for reducing the interference of external magnetic field, can be placed on the can inner screening to coil, in order to prevent that main flux from producing circulation shielding box fluting and cutting off the circulation approach in can, form the magnetic bypass in order to prevent can simultaneously, the shielding box fluting cuts off the magnetic bypass.

Claims (4)

1. pulses of current sensor is characterized in that:

Comprise coil and be serially connected in the noninductive precision resistance that coil outlet and its resistance and coil turn are complementary.

2. a kind of pulses of current sensor according to claim 1 is characterized in that:

Described coil case is the non-closed shielding can that a vertical, horizontal is provided with opening.

3. a kind of pulses of current sensor according to claim 1 and 2 is characterized in that:

Described coil is for for the individual layer coiling, and be serially connected with in its coil rack that a circle coiling direction is opposite with the spiral working direction, the outlet of winding and entering the mouth at the center of same end winding.

4. a kind of pulses of current sensor according to claim 3 is characterized in that:

Described coil rack is square-section and two loop configuration that semicircle combines.

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