JPH0619381B2 - Current sensor - Google Patents

Description

The present invention relates to a current sensor for detecting an alternating current or a pulse current, and in particular, it is configured by using an amorphous ribbon or an amorphous wire manufactured as a magnetic material. The present invention relates to a current sensor having a closed magnetic circuit.

[Prior Art] As a detection element for detecting an alternating current or a pulse current, a modified product or the like has been generally used. However, in the transformer, it is necessary to make the magnetic coupling between the primary winding that forms the main circuit and the secondary winding that forms the signal detection circuit tight because of its function, so avoid increasing the size and weight. In addition, the manufacturing process is complicated.

[Problems to be Solved by the Invention]

An object of the present invention is to solve the above-mentioned problems of the prior art, and by utilizing the large Barkhausen effect in an amorphous ribbon or an amorphous wire, the size and weight of the main circuit are reduced. An object of the present invention is to provide a current sensor which can be insulated to obtain a pulse voltage output proportional to the peak value of the main circuit current.

[Means for Solving the Problems] In the current sensor of the present invention, the primary conductor (2) for flowing a current to be detected, which is an alternating current or a pulse current, and the primary conductor (2) are
A ring-shaped magnetic circuit (1) formed by winding a magnetic amorphous ribbon or amorphous wire penetrating more than once,
The detection signal is extracted from both ends of the primary conductor (2) or both ends of the secondary conductor (3) penetrating the annular magnetic circuit (1).

That is, the constitution of the present invention is as follows. That is, a ring-shaped magnetic circuit (1) formed by winding a primary conductor (2) through which a detected current composed of an alternating current or a pulse current flows and a magnetic amorphous ribbon or amorphous wire through which the primary conductor (2) penetrates at least once. A pulse signal having a peak value according to the detected current peak value at both ends of the primary conductor (2) or both ends of the secondary conductor (3) penetrating the annular magnetic circuit (1). Characteristic current sensor.

[Work]

In the current sensor of the present invention, when a detected current consisting of an alternating current or a pulsed current is passed through the primary conductor, both ends of the primary conductor or both ends of the secondary conductor penetrating the annular magnetic circuit are subjected to the peak value of the detected current. A pulse signal having a peak value is generated.

〔Example〕

FIG. 1 shows the configuration of an embodiment of the current sensor of the present invention, in which 1 is an amorphous toroidal core made of a ferromagnetic amorphous ribbon, and 2 is a primary conductor through which a current to be detected is passed. Reference numeral 3 is a cylindrical secondary conductor made of non-magnetic metal, and has terminals A and B at both ends thereof.
4 is an insulator for electrically insulating the toroidal core 1 and the secondary conductor 3 from each other. In FIG. 1, the primary conductor 2 is
The cylindrical secondary conductor 3 is configured to penetrate once or more in an electrically insulated state.

When an alternating current or a pulsed current flows through the primary conductor 2, a magnetic field is generated according to the well-known right-handed screw rule, and the toroidal core 1 is magnetized by this. Here, the toroidal core 1 is composed of, for example, Fe ₇₈ B ₁₃ Si having a composition expressed in atomic%.
_When an amorphous ribbon such as No. 9 is used, a large Barkhausen effect is generated in the amorphous ribbon forming the toroidal core 1 due to the change in the magnetizing force due to the change in the current in the primary conductor 2, and the resulting sudden magnetic flux in the magnetic path. Based on the change, a voltage pulse is generated between the terminals A and B of the secondary conductor 3.

That is, since the toroidal core 1 is formed by winding the amorphous ribbon in a toroidal shape, the tension on the outer half thickness layer of the amorphous ribbon is 1 /
The compressive force is continuously generated in the two thick layers. On the other hand, when a tension σ is applied to the amorphous ribbon, the domain wall energy density γ of the 180 ° domain wall is proportional to λs · σ (where λs is the magnetostriction constant), so an iron-based ferromagnetic amorphous ribbon with a large magnetostriction constant λs is obtained. When a large tension σ is applied, the domain wall energy increases remarkably, and the magnetic flux reversal in the tension layer of the amorphous ribbon is such that when an external magnetic field exceeding the limit magnetic field H ^* of the reversal domain is applied, the domain wall is rotated by 180 °. It occurs in the form of the so-called large Barkhausen jump that runs at once in a magnetic domain (the large Barkhausen effect). If the magnetic field is smaller than the limit magnetic field H ^* , the inside of the ribbon will be 1/2.
It can be inferred that only domain wall motion occurs in the thick compression layer.

In the current sensor shown in FIG. 1, the peak value of the voltage pulse generated between the terminals A and B of the secondary conductor 3 is proportional to the peak value of the primary current if the waveforms of the primary currents are the same. Therefore, the primary current value can be known by measuring the peak value of this voltage pulse. Therefore, the current sensor shown in FIG. 1 can measure the value of the alternating current or the pulse current flowing in the primary conductor 2. Functions as a sensor.

When the current flowing through the primary conductor 2 is an alternating current or a pulse current, the terminal A,
Since a pulse voltage is generated between B, it can also be used as a phase measuring element for measuring the phase of an alternating current or a pulse current.

Figure 2 is a shows a configuration of a second embodiment of a current sensor of the present invention, same parts as in FIG. 1 are indicated by the same numbers, 5-1, _5-2, ... , 5-n are secondary conductors, respectively. Also in the case of the embodiment of FIG. 2, due to the large Barkhausen effect generated in the amorphous toroidal core 1 based on the change in the current in the primary conductor 2,
Secondary conductors ₅ 1, ₅ 2, ..., each of the terminal pairs of _{5-n (A 1, B} 1), (A 2, B 2), ..., (An, B
Since pulse voltages are generated in the same phase in n), it can be used as a pulse separator.

FIG. 3 shows the configuration of a third embodiment of the current sensor of the present invention, in which the same parts as in FIG. 1 are designated by the same numbers. In the embodiment of FIG. 3, the pulse voltage generated by the large Barkhausen effect generated in the amorphous toroidal core 1 based on the change in the current in the primary conductor 2 is transmitted from the terminals A and B provided at both ends of the primary conductor 2. It is taken out directly. The embodiment shown in FIG. 3 is suitable for the case where it is not necessary to insulate the signal detection circuit from the primary conductor, and the circuit configuration can be remarkably simplified. However, in this case, the primary conductor A due to the primary current,
The resistance drop voltage element and the reactance drop voltage element between B are the primary conductors A and B based on the large Barkhausen effect.
Since it occurs by being superimposed on the pulse voltage element generated between the two, in order to reduce the influence of the resistance drop voltage element and the reactance drop voltage element between the primary conductors A and B from the detection signal voltage between the primary conductors A and B, It is necessary to reduce the impedance voltage drop between the terminals A and B due to the current flowing through the primary conductor. Specifically, the cross-sectional area of the conductor between A and B of the primary conductor is increased, and the inductance of the amorphous toroidal core 1 is increased. Needs to be designed smaller. Further, in this case, it is necessary to increase the input impedance of a pulse voltage detection device (not shown) connected between the terminals A and B.

Figure 4 is a shows a configuration of a fourth embodiment of a current sensor of the present invention, same parts as in FIG. 1 are indicated by the same numbers, 5 secondary conductor, 6- ₁ , _6-2 is the bias magnetization conductor. The bias magnetic conductors _6-1,
Connected to 6- _{2 E} 1, _{E 2} denotes a DC power _{source, S 1,} S ₂
Is a switch, and R ₁ and R ₂ are variable resistors.

In the embodiment shown in Figure 4, the bias magnetic conductor ₆ 1, 6 ₂ switches _S 1 that is connected to, _{S 2} was arbitrarily opened and closed, the variable resistor from each of the DC power source _E 1, _{E 2} Amorphous toroidal core 1 is obtained by passing a current set to an arbitrary value in a desired direction through R ₁ and R _2.
A desired DC bias magnetizing force can be applied to. In such a state, when an alternating current or a pulse current is passed through the primary conductor 2, the phase of the pulse voltage generated in the secondary conductor 5 by the large Barkhausen effect generated in the amorphous ribbon forming the toroidal core 1 is the DC bias magnetizing force. It depends on the size of. Therefore, according to the embodiment shown in FIG. 4, it is possible to control the phase of the pulse voltage generated when the alternating current or the pulse current is passed through the primary conductor 2.

The amorphous ribbon used in the current sensor of the present invention is
The composition is not limited to the one having the composition of Fe ₇₈ B ₁₃ Si ₉ described above, and an iron-based amorphous ribbon having another composition having ferromagnetism may be used. Amorphous ribbons can generally have their magnetic properties improved by heat treatment (annealing), but in the case of certain types of amorphous ribbons, a highly sensitive current sensor can be realized without heat treatment. .

Although the above description has been made for the case where the current sensor is formed using the amorphous ribbon, it can be applied to the case where the thin wire-shaped amorphous material is used.
Similarly, it is possible to construct a current sensor for detecting an alternating current or a pulse current.

FIG. 5 shows an application example of the current sensor of the present invention, and exemplifies the configuration in the case where a leakage detection sensor is formed using the current sensor of the present invention. In the figure, 8 is electrical path 9 1 a _load, is connected to the power supply 11 via the _9-2. Path ₉ 1, the _9-2 amorphous toroidal core 1,
Primary conductor ₂ 1, have been inserted a current sensor of the present invention comprising _2-2 secondary conductors 5, path ₉ 1, 9 ₂ each primary conductor ₂ 1, 2 ₂ and the breaker 10 ₁ ,Ten
- is guided to the power supply 11 via a _2. A detection signal between both terminals A and B of the secondary conductor 5 of the current sensor is applied to the detection circuit 12.

Now load 8 or path ₉ 1, leakage point A at _9-2
When leakage occurs between B and the leakage current Ig,
It flows through the ground point of 11 or the stray capacitance C ₀ on the power supply side. The magnetomotive forces in the current sensor, which are based on the load current, cancel each other out, so that they are only proportional to the leakage current Ig, thereby generating a voltage pulse between the terminals A and B. In the detection circuit 12, this voltage pulse is applied to an amplification circuit 14 via an input circuit 13 composed of a voltage follower to receive required amplification, and is applied to a level setting circuit 15 to output a pulse whose level is set to a constant value. Cause
The pulse counting circuit 16 counts the output pulse of the level setting circuit 15 for the time set by the time setting circuit 17. The output circuit 18 generates an alarm signal and outputs a cutoff signal when the count value of the pulse count circuit 16 exceeds a certain value. Predetermined alarm is performed by an alarm signal, breaker 10-1 by interrupting _{signal, 10-2} operates, path 9 _1, 9 ₂ are disconnected from the power source 11, the purpose of protection is achieved. In addition, the number of counts that generate an alarm and the number of counts that output a cutoff signal are made different,
A stepwise protection operation may be performed. Power supply part
Reference numeral 19 supplies required power to each part of the detection circuit 12.

According to the leakage detection sensor shown in FIG. 5, since the pulse voltage proportional to the leakage current Ig is generated between the terminals A and B of the secondary conductor, the pulsing circuit is unnecessary and the circuit is simplified. It is advantageous when Further, there is an advantage that high-speed detection can be performed without waiting for the time for reaching the peak value of the leakage current Ig. Further, as a result of using the current sensor of the present invention, it can be manufactured in a smaller size, lighter weight and at a lower cost than that using a normal zero-phase current transformer.

The sixth example shows a second application example of the current sensor of the present invention, and illustrates the configuration in the case where a directional grounding relay is formed using the current sensor of the present invention. In the figure, 8 is electrical path ₉ 1 a _load, 9-2 are connected to a power supply 11 via the _9-3. Path _{9 1,} 9 2, the _9-3 amorphous toroidal core 1, the primary conductor _{2 1,} 2 2, ₂ 3,
Secondary conductor consists of 5 have a current sensor is inserted in the present invention, paths _{9 1,} 9 2, 9 ₃ each primary conductor 2
- _{1, 2} 2, is guided to the power source 11 through a _2-3 and breaker 10. The detection signal between the terminals A and B of the secondary conductor 5 of the current sensor is applied to the detection circuit 12. Reference numeral 21 is a grounding transformer, which generates a zero-phase voltage on its secondary side. This zero-phase voltage output is the amorphous toroidal core 22, the primary conductor 23,
It is connected via a resistor 25 to the primary conductor 23 of another current sensor of the present invention consisting of the secondary conductor 24, and the detection signal between both terminals C and D of the secondary conductor 24 is applied to the detection circuit 12.

Now load 8 or path _{9 1,} 9 2, the results of Chiro between the earth絡点B in _9-3, Chiro current Ig power
It flows through the ground point of 11 or the stray capacitance C ₀ on the power supply side. The magnetomotive forces in the current sensor, which are based on the load current, cancel each other out, so that they are only proportional to the ground fault current Ig, thereby generating a voltage pulse between the terminals A and B. In this voltage pulse detection circuit 12, is applied to the amplifier circuit 14 ₁ via the ground fault current partial pulse input circuit 13 ₁ receives the required amplification.

On the other hand, the zero-phase voltage is generated in the power supply 11 due to the occurrence of the ground fault. This zero-phase voltage is detected via the grounding transformer 21, which causes an alternating current to flow in the primary conductor 23 via the resistor 25,
A magnetomotive force proportional to the zero-phase voltage is generated, which causes a voltage pulse to be generated between both terminals C and D of the secondary conductor 24 in the vicinity of the zero-phase voltage rising point. This voltage pulse is detected by the detection circuit 12
In, it applied to the amplifying circuit 14 ₂ through the zero-phase voltage of the pulse input circuit 13 ₂ receives the required amplification.

The phase comparator circuit 20 both amplifier circuits 14 1 _compares the _14-second output of the phase, to generate an output pulse when in predetermined phase relationship. The pulse count circuit 16 counts the output pulse of the phase comparison circuit 20 for the time set by the time setting circuit 17. When the count value of the pulse count circuit 16 exceeds a certain number, the output circuit 18 generates an alarm signal to give a predetermined alarm and outputs a cutoff signal to output the breaker 10.
To operate. This makes it possible to determine the direction of the ground fault point B as seen from the power source 11 and detect the occurrence of a ground fault, and to perform an alarm generation and power shutdown operation. Power supply 19
Supplies the required power to each unit in the detection circuit 12.

According to the directional grounded relay shown in FIG. 6, the secondary conductor 5
Since a voltage pulse proportional to the ground fault current Ig is generated between the terminals A and B and a voltage pulse proportional to the zero-phase voltage is generated between the terminals C and D of the secondary conductor 24, the pulsing circuit becomes unnecessary. In addition, the phase comparison of the direction determination is easy, and the circuit is simple, which is advantageous when integrated into an IC. There is also an advantage that high-speed detection can be performed without waiting for the time to reach the peak value of the zero-phase voltage. Further, as a result of using the current sensor of the present invention, it can be manufactured in a smaller size, lighter weight and at a lower cost than that using a normal zero-phase current transformer.

FIG. 7 shows a third application example of the current sensor of the present invention, and illustrates the configuration in the case where an engine tachometer is formed using the current sensor of the present invention. In the figure, 31 is a ignition coil, via its primary coil 13 ₁ from the battery E for each contact disconnection of the contact points 32,
It pulsed flow the primary current Ip with respect to ground, which pressure pulses generated in the secondary coil 31- ₂ by is supplied to the engine spark plug (not shown) via a not shown distributors. The current sensor of the present invention is inserted between the contact point 32 and the ground, and the primary current of the ignition coil flows through the primary conductor 2 of the ignition coil, which causes a magnetomotive force in the amorphous toroidal core 1 to cause the secondary conductor 5 to move. A voltage pulse is generated between terminals A and B,
This voltage pulse is applied to the detection circuit 34. In FIG. 7, the capacitor 33 is provided to prevent the occurrence of spark discharge due to the disconnection of the current at the contact point 32 and protect the contact point 32.

In the detection circuit 34, the voltage pulse between the terminals A and B is applied to the waveform shaping circuit 36 via the input circuit 35 and undergoes predetermined waveform shaping to generate an output pulse. This output pulse is applied to the pulse count circuit 37 and counted by the time setting circuit 38 for a preset time. The multiplication circuit 39 multiplies the count value of the pulse count circuit 37 by a constant value to generate a signal indicating the engine speed per unit time. The output circuit 40 generates an output for displaying the engine speed on a display (not shown) according to the output signal of the multiplication circuit 39, and also generates an alarm signal when the engine speed exceeds a preset constant value. Then, a predetermined alarm is given. The power supply unit 41 supplies required power to each unit in the detection circuit 34.

FIG. 8 shows another configuration example of the engine tachometer which is an application example of the present invention, in which the current sensor is a secondary coil of the ignition coil 31 as compared with the case of FIG.
31- ₂ are different in that it is inserted in the output side, the other configuration is the same, also the operation 7
There is no difference from the case in the figure.

The engine tachometer shown in FIG. 7 and FIG. 8 has a detection circuit 34 by applying the current sensor of the present invention.
Can be provided so as to be isolated from the engine ignition circuit, and since it essentially generates a pulse output, it is suitable for digital display and is excellent in that there is substantially no error.

〔The invention's effect〕

As described above, according to the current sensor of the present invention, when a detected current composed of an alternating current or a pulse current is passed through the primary conductor, both ends of the primary conductor or both ends of the secondary conductor penetrating the annular magnetic circuit are exposed. A pulse signal having a peak value corresponding to the peak value of the detected current is obtained. Since the current sensor of the present invention essentially obtains a pulse signal, it is advantageous when applied to a device using a microprocessor or the like. Further, the current sensor of the present invention can be used by being insulated from the primary conductor through which the current to be detected is passed, and can be manufactured in a small size, a light weight and at a low cost.

[Brief description of drawings]

1 to 4 are views showing an embodiment of the current sensor of the present invention, FIGS. 5 to 8 are views showing an application example of the current sensor of the present invention, and FIG. A leakage detection sensor, FIG. 6 shows a direction ground fault relay, and FIGS. 7 and 8 show an application as an engine tachometer, respectively. 1 ...... Amorphous toroidal core 2,2 _{1, 2} 2, 2 ₃ ...... primary conductor _{3,5,5- 1, 5- 2, ...,} 5-n ...... secondary conductor 4 ...... insulator _{6-1, 6-2} ...... bias magnetization conductor 8 ...... load 9 _{1, 9} 2, 9 ₃ ...... path 10 ...... breaker 10 _1, 10 ₂ ...... breaker 11 ...... power 12 ...... detecting circuit 13 ...... input circuit 13 1 _...... grounding current partial pulse input circuit 13 2 _...... zero-phase voltage of the pulse input circuit 14,14- _1, 14 2 _...... amplifier circuit 15 ...... level Setting circuit 16 …… Pulse counting circuit 17 …… Time setting circuit 18 …… Output circuit 19 …… Power supply unit 20 …… Phase comparison circuit 21 …… Grounding transformer 22 …… Amorphous toroidal core 23 …… Primary conductor 24 …… secondary conductor 25 ...... resistor 31 ...... ignition coil 31- 1 _...... primary coil 31- 2 _...... secondary coil 32 ... contact point 33 ...... capacitor 34 ...... detecting circuit 35 ...... input circuit 36 ...... waveform shaping circuit 37 ...... pulse counting circuit 38 ...... Time setting circuit 39 ...... multiplier circuit 40 ...... output circuit 41 ...... power unit

Claims (1)

[Claims] 1. A primary conductor for flowing a current to be detected comprising an alternating current or a pulsed current, and a ring-shaped magnetic circuit formed by winding a magnetic amorphous ribbon or an amorphous wire through which the primary conductor penetrates at least once. A current sensor characterized in that a pulse signal having a peak value according to a peak value of a detected current is obtained at both ends of a conductor or both ends of a secondary conductor penetrating the annular magnetic circuit.