KR20070018652A - High precise and miniaturized current transformer, method for manufacturing the same, trip current circuit and using the same - Google Patents

Abstract

The present invention relates to a high-precision and ultra-small current transformer, a method of manufacturing the same, and an instantaneous shut-off circuit using the same. The current transformer of the present invention has a coil portion formed on at least one surface of an insulating film having a flexible band-shaped structure, each coil portion being formed in a plane coil shape having a predetermined number of turns and connected in series, The insulating film formed with the adhesive is formed to have a hollow cylindrical structure as a whole, and has lead terminals at both ends of the coil portion. Therefore, it is possible to provide a current transformer excellent in current detection performance and extremely small by repeatedly forming a plurality of coil patterns on a lightweight insulating film and connecting them in series to constitute a current transformer

Current transformer, earth leakage breaker, overcurrent, trip, coil, induction current

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high precision and miniaturized current transformer, a method of manufacturing the same,

FIG. 1 and FIG. 2 show a process of manufacturing a high-precision and small-sized current transformer according to the present invention. 1 and 2, (a) is a plan view, and (b) is a cross-sectional view taken along the line b-b in (a).

FIG. 3 is a perspective view schematically showing a high-precision, micro-sized current transformer according to the present invention manufactured according to the process shown in FIGS. 1 and 2. FIG.

4 is a circuit diagram of an instantaneous shut-off circuit for shutting off an overcurrent using a high-precision, micro-current transformer according to the present invention.

5 is a circuit diagram of an instantaneous shut-off circuit for detecting and interrupting a short circuit by using a high-precision and small-sized current transformer according to the present invention.

The present invention relates to a current transformer, a method of manufacturing the same, and an instantaneous shut-off circuit using the same. More specifically, the present invention relates to a current transformer, The present invention relates to a micro-current transformer, a method of manufacturing the same, and an instantaneous shut-off circuit using the same.

In general, electrical energy is used conveniently in homes and factories. As a result, it causes safety accidents such as large-scale fire or electric shock due to carelessness, overcurrent, short circuit, short circuit, etc., In order to prevent a safety accident, wiring breakers and earth leakage breakers have been installed.

The circuit breaker is used to prevent damage to the load device and circuit by automatically shutting off the circuit when an abnormal current occurs due to over current or short circuit on the electric line in the low voltage circuit of AC 460V or less. The leakage circuit breaker is used to prevent personal injury and fire caused by leakage current when leakage current is generated. Recently, a circuit breaker for wiring has been developed to additionally use an electric leakage blocking circuit and an electric leakage blocking mechanism to double the electric leakage.

As a representative device for detecting the overcurrent due to a short-circuit accident and shutting off the power, there is a thermo-tripping mechanism using a bimetal. In the circuit breaker using the thermal tripping mechanism, the bimetal of the thermal overcurrent detecting element is thermally deformed due to the heat generated by the abnormal current in the event of an overcurrent or a short circuit, and the bimetal is thermally deformed to mechanically push the trip mechanism to operate the main switch And has a structure to cut off power.

However, since the overcurrent or short-circuit breaking capacity of a conventional circuit breaker is 10 times or more the rated current according to the KS standard, it is usually applied to a high current of 1,000 A or more. In order to absorb the arc and heat generated in connection with the interruption of such a high current, an absolute space must be secured. Therefore, there is a limit in reducing the size of the instantaneous shut-off detection device. As the size of the instantaneous shut-off sensing device increases, it becomes a decisive reason to lower the performance of the product. In addition, when the power supply is cut off due to thermal deformation of the bimetal, the operation time may be delayed to a considerable extent, which is not preferable, and the operation point thereof is not constant. Therefore, There is a problem that the contact portion of the breaker is fused or the trip mechanism is damaged.

On the other hand, a typical device for detecting a short circuit is a Zero-Phase Current Transformer (ZCT). This video deflector is a device that detects leakage of current regardless of whether it is over current or not. The principle is as follows. For example, when a load is connected to a single-phase AC power source and there is no leakage of current, the current flowing through the power line entering the load and the power line coming from the load are opposite to each other and the current values are exactly matched. Therefore, the magnetic fields generated on the two power lines entering and leaving the load are canceled out to zero, and when the two power lines are passed together to the core of the current transformer, the output of the current transformer becomes exactly zero. On the other hand, when a short circuit occurs, the current value of the power line coming out of the load becomes smaller than the current value of the power line entering the load, and the resultant magnetic field is not zero, so that the output of the current transformer is not zero.

However, since this video current transformer uses an iron core, there is a limitation in downsizing, and the characteristic curve of the current is easily saturated, which leads to a disadvantage that the linearity is lowered. Further, in order to increase the sensitivity of the current transformer, there is a problem that manufacturing cost is high because the iron core must use a high-priced and expensive material called permalloy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a current transformer that precisely senses an overcurrent and is very small.

It is another object of the present invention to provide a method for manufacturing such a high-precision and small-sized current transformer with a simple process and a low cost.

It is still another object of the present invention to provide an instantaneous shut-off circuit that performs a shut-down operation accurately and at a high speed with no time delay using the high-precision and small-sized current transformer as described above.

SUMMARY OF THE INVENTION The present invention provides a high-precision and small-sized current transformer according to the present invention, which is formed in a flat coil-like shape having a predetermined number of turns on at least one surface of an insulating film having a flexible band- And a coil portion having a plurality of coil patterns connected to each other in series. The insulating film on which the coil portion is formed has a hollow cylindrical structure as a whole, and has lead terminals at both ends of the coil portion.

At this time, the hollow cylindrical structure may be formed by laminating the insulating film on which the coil part is formed a plurality of times, or by laminating a plurality of insulating films on which the coil part is formed.

In addition, an overcurrent detection module or an electric leakage detection module may be mounted on the insulating film on which the coil part is formed.

SUMMARY OF THE INVENTION The present invention provides a method of manufacturing a high-precision and small-sized current transformer according to the present invention, which is provided for achieving the object of the present invention, Forming a coil part having a plurality of coil patterns in a plane shape; And winding the insulating film on which the coil is formed to form a hollow cylindrical structure as a whole.

According to another aspect of the present invention, there is provided an instantaneous shut-off circuit comprising the above-described current transformer. That is, the instantaneous shut-off circuit according to the present invention comprises: a first current transformer arranged such that one power supply line of a single-phase AC power supply passes through the hollow; A second current transformer arranged such that the other power supply line of the single-phase AC power supply passes through the hollow; And a comparator comparing the sum of the outputs of the first and second converters with a predetermined reference value to output a shutoff signal for shutting off the power supply when the sum of the outputs of the first and second converters exceeds the predetermined reference value And a blocking signal generating unit.

At this time, depending on the connection of each terminal of the first and second current transformers and the setting of the reference value, the instantaneous shutoff circuit detects a short circuit to generate a shutoff signal or detects an overcurrent to generate a shutoff signal do.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the above-described embodiments. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention. Also, although specific terms are employed herein, they are used for purposes of describing the invention only to those of ordinary skill in the art, and are not used to limit the scope of, or limit the scope of, the invention.

1 and 2 are diagrams for explaining a process of manufacturing a high precision and micro current transformer according to an embodiment of the present invention, wherein (a) is a plan view, (b) FIG. 3 is a perspective view illustrating a current transformer according to an embodiment of the present invention manufactured through the process shown in FIGS. 1 and 2. FIG.

1 to 3, a method of manufacturing a current transformer according to the present embodiment and a current transformer manufactured by the method will be described in detail.

First, the insulating film 10 is prepared. The insulating film 10 is a substrate film on which a coil pattern is formed and curled to form a hollow cylindrical shape, and a power line is passed through the insulating film 10 to form a current transformer. Therefore, it is provided in a flexible and long strip shape so that it can be subsequently spun. In addition, it is preferable that it has heat resistance so as to withstand the heat generated at the time of the flow operation. As such an insulating film, a material widely used for a flexible circuit substrate such as a polyimide resin or a polyimide-amide resin is suitable.

Then, a plurality of coil patterns 20 arranged in a line in a plane coil shape having a predetermined number of turns are formed on the insulating film 10. The coil pattern 20 is made of a metal having good electrical conductivity such as copper, aluminum, gold, silver, or an alloy of these metals. The method of forming the coil pattern 20 in the plane varies. For example, the coil pattern 20 is formed by various known methods such as printing with a screen printing technique using a metal paste or etching a metal thin film laminated on the insulating film 10 using plating, thermocompression bonding or an adhesive layer can do.

Next, as shown in FIG. 2, a connecting portion 40 and lead-out terminals 45 and 46 for connecting the coil patterns 20 in series are formed. Specifically, the insulating layer 30 is formed on the entire surface of the insulating film 10 in the state shown in FIG. The insulating layer 30 is also preferably flexible, and may be made of the same material as the insulating film 10. Then, the insulating layer 30 is etched to form contact holes 35 exposing both end portions 21 and 22 of the respective coil patterns 20. The connecting portions 40 connecting the end portions 21 and 22 of the respective coil patterns exposed by the contact holes 35 so that the respective coil patterns are connected in series are formed and at the same time the lead terminals 45 and 46 . The material forming the connection portion 40 and the lead terminals 45 and 46 may be the same metal or metal alloy as the coil pattern 20. The connecting portion 40 and the lead-out terminals 45 and 46 can be formed by various known methods in the same manner as the coil pattern 20.

Finally, a protection film 50 is formed on the entire surface of the film on which the connection portion 40 and the lead-out terminals 45 and 46 are formed, to protect the coil portion (coil portion and the coil portions). The protective film 50 is also required to have a flexible property, and is preferably formed of the same material as the insulating film 10 or the insulating layer 30. [

The number and shape of the coil patterns 20 and the number of the coil patterns 20 and the shapes and arrangement of the connecting portions 40 and the lead terminals 45 and 46 are not limited to those shown in Figs. It goes without saying that various modifications are possible. For example, the number of turns of each coil pattern 20 and the number of coil patterns are appropriately determined according to the current ratio between the primary and secondary sides required by the current transformer and the degree of stacking or superimposing of the unit insulation films, which will be described later.

Although the coil portion is formed only on one surface of the insulating film 10 in the above description, the coil portion may be formed on both surfaces of the insulating film 10.

In the above description, the coil pattern 20 and the connecting portion 40 are formed with the insulating layer 30 interposed therebetween. However, it is also possible to form the coil pattern 20 and the connecting portion 40 using a metal wire insulated and coated with an enamel wire, A plane coil may be formed at one time.

Although the protective film 50 for protecting the coil part is formed in the above, the protective film 50 may be omitted.

5), an overcurrent detecting module (400 in FIG. 4), and a necessary switching device (such as an SCR) may be mounted on the insulating film 10 together with an electrical leak detecting module . In this case, necessary wiring electrically connected to the input / output terminals of the integrated circuit chip constituting each detection module is formed together in the process of forming the coil pattern 20 or the connection portion 40.

When a coil portion having a plurality of coil patterns 20 is formed on the insulating film 10 in the form of a strip, the lead terminals 45 and 46 are electrically connected to the outside So as to manufacture a micro-current transformer 100 of a cylindrical structure having a hollow 110 at the center as shown in Fig. At this time, the number of effective turns of the coil pattern 20 can be increased by wrapping the insulating film 10 and folding it in multiple layers as shown in Fig. Further, although not shown, a plurality of insulating films on a flat strip formed with a coil section as shown in FIG. 2 may be prepared and stacked to increase the number of effective turns of the coil pattern 20. FIG. Furthermore, it is needless to say that the insulating film may be a single-layer cylindrical structure without being overlapped or laminated. In other words, the number of turns of each coil pattern 20, the number of coil patterns, and the number of superimposed or stacked layers of the insulating film 10 in the cylindrical structure are set such that the turns ratio of the primary side and the secondary side required in the instantaneous interruption circuit using a current transformer It is possible to appropriately set the size of the current transformer 100 to be small as much as possible.

In the meantime, the hollow 110 is a part through which one strand of the power supply line passes, and a current transformer is fixed to the center of the hollow 110 of the current transformer 100 as shown in Fig. 3 And the entire case is wrapped in an outer case. The specific shape and size of the outer case can be changed depending on the application. Specifically, four terminals of the current transformer wrapped around the external case are formed. Specifically, the input terminal and the output terminal of the lead, which is the primary side of the current transformer through the hollow 110, and the two outgoing terminals 45, 46).

As described above, in the current transformer according to the present embodiment, a plurality of plane coil patterns are formed on a flexible insulating film, and the transformer is made into a cylindrical structure by winding it so that its size can be made very small. Meanwhile, the current transformer according to the present invention is an air core type having no iron core, and can detect a current with much higher precision than a conventional video current transformer at a lower manufacturing cost. That is, since the current transformer according to the present invention is air-core type, the current characteristic curve can not be easily saturated and the linearity can be maintained, and precise and accurate current characteristics can be obtained,

4 is a circuit diagram of an embodiment in which an instantaneous shut-off circuit is constructed using a high-precision, micro-current transformer according to the present invention. The instantaneous shutoff circuit of this embodiment is a circuit for detecting an overcurrent caused by an accident such as short-circuiting of a single-phase AC power supply to generate a power shutdown signal, and its construction and operation will be described as follows.

The instantaneous shut-off circuit of the present embodiment includes two current transformers 100 of the above-described embodiment, which are referred to as a first current transformer CT ₁ and a second current transformer CT ₂ , respectively. The instantaneous shut-off circuit of the present embodiment includes an overcurrent detecting module 400 as a shut-off signal generating unit, a thyristor (SCR) as a switching device, and a solenoid-type trip coil 300. Here, all the circuit elements except the trip coil 300 and the capacitor C ₁ can be implemented as one integrated circuit chip and mounted on the insulating film 10 described above.

A first current transformer (CT ₁₎ and a second current transformer (CT ₂₎ is the primary side as a power supply line of each single strand of the single-phase AC power to the load 200, 210 and 220, each of the hollow (110 in Fig. 3) And the two lead terminals (45 and 46 in Fig. 3) of the secondary side are connected to each other with different polarities. That is, the first draw-out terminal 45 of the first current transformer CT ₁ and the second draw-out terminal 46 of the second current transformer CT _{2 are} connected and the second draw-out terminal 45 of the first current transformer CT ₁ 46 and the first outgoing terminal 45 of the second current transformer CT _{2 are} connected. Therefore, the secondary currents, which are the primary currents of the two power supply lines 210 and 220, which are in opposite phases to each other, are changed according to the predetermined ratio of the first current transformer CT ₁ and the second current transformer CT ₂ and output, And output to the node a. For example, if a winding ratio is set such that an induction current of 100 mA is generated on the secondary side of each of the current transformers when a current of 1000 A, which is an overcurrent, flows through the power supply lines 210 and 220 due to an accident such as a short circuit, If not, it will be 200mA.

Between the nodes a and b, the voltage-dividing resistors R ₁ and R ₂ connected by an appropriate voltage-dividing ratio are connected and a voltage resulting from the voltage drop at the node c between R ₁ and R ₂ is applied to one side of the comparator of the overcurrent detecting module 400 Terminal. Further, the other terminal of the comparator, the diode via the D ₂ are applied with a voltage Ref1 of the reference value that is the basis for the over-current determination, is whether the overcurrent is detected by the comparator in the over-current detection module 400, the gate terminal of the thyristor (SCR) G.

The diode D ₁ connected to the node a rectifies the sum of the output currents of the first current transformer CT ₁ and the second current transformer CT ₂ by half-wave rectification and supplies the power Vcc of the overcurrent detection module 400 and the trip coil 300 As shown in Fig. In other words, a diode-current rectified by the D ₁ through a resistor R _D is supplied as a power supply of the over-current detection module 400, and the other by a a resistance R _D is not supplied to the over-current detection module, the current is supplied to the capacitor C ₁ Is charged.

In this way, the power source when the line 210, an abnormal current is an overcurrent flows in the overcurrent detection module 400 export the power-off signal by detecting this, the gate of the thyristor (SCR), whereby the thyristor is a capacitor for C ₁ The trip coil 300 is operated by using the charged electric charge and a cutoff mechanism (not shown) connected to the trip coil 300 blocks the power lines 210 and 220. Thus, much more accurate and instantaneous power cut-off is possible compared to the conventional thermal-type trip mechanism.

On the other hand, the embodiment shown in Fig. 4 is an instantaneous shut-off circuit that detects an overcurrent due to an accident such as a short circuit and cuts off the power supply, but can not perform an operation of detecting a short circuit and cutting off the power supply in case of a short circuit. To this end, the embodiment shown in Fig. 5 is an instantaneous shut-off circuit as a leakage cut-off circuit. Referring to FIG. 5, the instantaneous shutoff circuit of the present embodiment will be described with reference to a point different from the embodiment shown in FIG.

The instantaneous shut-off circuit of this embodiment is largely different from the instantaneous shutoff circuit shown in Fig. 4 in the connection method of the two outgoing terminals 45 and 46 of the first current transformer CT ₁ and the second current transformer CT ₂ . That is, in this embodiment, each of the first current transformer (CT ₁₎ and a second current transformer (CT ₂₎ the same polarity connection between each of the two lead-out terminals (the first current transformer (CT ₁₎ and a second current transformer (CT ₂₎ Out terminals 45 and the respective second outgoing terminals 46 of the first current transformer CT ₁ and the second current transformer CT _{2 are} connected to each other. Thus, the first byeonryu group (CT ₁₎ and a second respective output of a current transformer (CT ₂₎ is If this is the reverse-phase short-circuit, the first current transformer (CT ₁₎ and the sum as a node in the output of the second current transformer (CT ₂₎ the current flowing in a will be zero. On the other hand, when a short circuit occurs, the current flowing through the node a becomes a non-zero value, and is compared with a reference value 0 of the electrical leak detecting module 500, and a power shutoff signal is applied to the gate of the thyristor (SCR). Thus, as in the embodiment shown in FIG. 4, the instantaneous shutoff circuit shown in FIG. 5 can immediately shut off the power supply when a short circuit occurs.

In this embodiment, instead of using the outputs of the first and second current transformers CT ₁ and CT ₂ as the power source for the electric leakage detecting module 500 and the power source for operating the trip coil 300, AC power is used directly. If the sum of the outputs of the first and second converters CT ₁ and CT ₂ is 0 and a significant amount of leakage does not occur in the normal case (when a short circuit does not occur), the leakage detection module 500 and the trip coil 300) is insufficient.

As described above, the leakage cutoff circuit of the present embodiment can detect the leakage current much more accurately at a lower cost than the conventional leakage current cutoff circuit using the video current transformer, and can cut off the power.

Best Mode for Carrying Out the Invention Best modes of the present invention have been disclosed. However, the present invention can be modified in various ways within the scope of the technical idea described in the following claims.

For example, although the instantaneous interruption circuit (FIG. 4) as an overcurrent detection and interruption circuit and the instantaneous interruption circuit (FIG. 5) as an electrical leak detection and interruption circuit are shown and described as separate circuits in the above embodiments, the overcurrent detection, It is possible to constitute one instantaneous blocking circuit which is possible at the same time. In this case, all the circuit elements including the first and second current transformers CT ₁ and CT ₂ are used as a common circuit element of the combined instantaneous shutoff circuit, except for the overcurrent detection module 400 and the electrical leak detecting module 500 , But only the connection of the two outgoing terminals 45, 46 of the first and second current transformers CT ₁ , CT ₂ may be made different.

Also, in the above-described embodiments, the single-phase AC power source is taken as an example, but the current transformer and the instantaneous shut-off circuit of the present invention can be applied to the three-phase AC power source. In this case, the current transformer according to the present invention may be disposed for each power line of the three-phase AC power source.

According to the present invention, a plurality of coil patterns are repeatedly formed on a lightweight insulating film, and then connected in series to constitute a current transformer, it is possible to provide a current transformer excellent in current detection performance and very small in size. Further, when the instantaneous shut-off circuit is constructed using the high-precision and micro-current transformer according to the present invention, it is possible to precisely judge whether the overcurrent or the short circuit is caused at a low cost, to immediately perform the power shutoff operation, It is possible.

Claims (13)

And a coil portion having a plurality of coil patterns formed in a plane coil shape having a predetermined number of turns and connected in series, on at least one surface of an insulating film having a flexible band- Wherein the insulating film on which the coil portion is formed is entirely hollow and has a cylindrical shape and has lead terminals at both ends of the coil portion. The method according to claim 1, Wherein the hollow cylindrical structure is formed by overlapping the insulating film on which the coil portion is formed by a plurality of turns. The method according to claim 1, Wherein the hollow cylindrical structure is formed by stacking a plurality of the insulating films on which the coil part is formed. The method according to claim 2 or 3, And an overcurrent detecting module is mounted on the insulating film together. The method according to claim 2 or 3, And an electrical leak detecting module is mounted on the insulating film. Forming a coil part in a plane on at least one surface of an insulating film having a flexible band-shaped structure, the coil part having a plurality of coil patterns each having a predetermined number of turns and connected in series; And And winding the insulating film on which the coil part is formed to form a hollow cylindrical structure as a whole. The method according to claim 6, Wherein the step of forming the coil part comprises: Forming a plurality of coil patterns each having a predetermined number of turns in a plane on at least one surface of the insulating film; Forming an insulating layer on the entire surface of the insulating film on which the plurality of coil patterns are formed; Etching the insulating layer to form contact holes exposing both end portions of the coil patterns; And And forming a connection portion connecting ends of each coil pattern exposed by the contact holes with a conductive metal in series. 8. The method according to claim 6 or 7, Wherein the step of winding the insulating film into a hollow cylindrical structure is repeated a plurality of times so that the insulating film on which the coil portion is formed is superposed. 8. The method according to claim 6 or 7, Wherein a plurality of the insulating films on which the coil portions are formed are stacked in a step of winding the insulating film into a hollow cylindrical structure. 4. The transformer according to any one of claims 1 to 3, wherein one power source line of the single-phase AC power source is arranged to pass through the hollow; A second current transformer according to any one of claims 1 to 3, wherein the other power supply line of the single-phase AC power supply is arranged to pass through the hollow; And And outputs a shutoff signal for shutting off the power supply when the sum of the outputs of the first and second current transformers exceeds the predetermined reference value by comparing the sum of the outputs of the first and second current transformers with a predetermined reference value And a blocking signal generating unit. 11. The method of claim 10, The first pull-out terminal of the first current transformer and the first pull-out terminal of the second current transformer are connected to be a sum of the outputs of the first and second current transformers, the predetermined reference value is 0, And detecting whether or not a short circuit is present. 11. The method of claim 10, The first output terminal of the first current transformer and the second output terminal of the second current transformer are connected to be a sum of the outputs of the first current transformer and the second current transformer, Instantaneous shut-off circuit. 13. The method according to claim 10 or 12, Wherein the blocking signal generator comprises an integrated circuit chip, Wherein the sum of the outputs of the first current transformer and the second current transformer is rectified and used as a power source of the cut-off signal generating unit.

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