JP6768434B2 - Current sensor and current detector - Google Patents

Description

The present invention relates to a current sensor including a Rogowski coil formed in an annular shape that can surround a current path of a current to be detected, and a current detection device including the current sensor.

As an example of this type of current sensor, the current sensor disclosed by the applicant of the present application in Patent Document 1 below is known. This current sensor is formed in a double ring structure by two air core coils (Rogovski coils). In this case, the double ring structure is either a structure in which the two air core coils are paralleled and integrated without crossing or twisting, or a structure in which the two air core coils are twisted and integrated. Can be adopted.

Further, in this current sensor, two cables cut and trimmed from a predetermined cable are used as winding cores for each air core coil, and the same number of turns and the same winding pitch are used for these two cables. Each air core coil is formed by winding the winding with. Therefore, each air-core coil has the same winding diameter (that is, the cross-sectional area of the air-core coil), the same winding pitch, and the same winding length. The detection characteristics (frequency characteristics, output level, etc.) are the same (in the same state). Further, in this current sensor, each air core coil is connected in series to form one air core coil (Rogovski coil) as a whole. According to this current sensor, since the detection characteristics (especially frequency characteristics) of the two air-core coils connected to each other are the same, the air-core coil while ensuring an output level higher than that when there is only one air-core coil. It is possible to maintain the same frequency characteristics as when there is only one.

Japanese Unexamined Patent Publication No. 2013-213843 (Page 5-7, Fig. 1-6)

By the way, when the detection target current to be detected is a signal whose frequency component contained is over a wide frequency band, such as a rectangular wave signal, or when the frequency of the detection target current is some known frequency. In the case of a signal that changes with time to any of them, the current sensor needs to have a wide frequency characteristic capable of detecting such a detection target current. However, although the above-mentioned current sensor is provided with two air-core coils, the frequency characteristics as a whole are the same as the frequency characteristics of one air-core coil, so that the various detection target currents described above are detected. There is a problem to be improved that a situation that cannot be obtained arises.

The present invention has been made to improve such a problem, and an object of the present invention is to provide a current sensor having a wide frequency characteristic and a current detection device provided with the current sensor.

In order to achieve the above object, the current sensor according to claim 1 is composed of a sensor body formed in an annular shape capable of surrounding a current path of a current to be detected and a winding formed in a winding core, and the sensor. along the length of the body, and a multiple Rogowski coils that will be respectively disposed within the sensor body over substantially the entire area of the sensor body, said plurality of Rogowski coils, the winding core And because the configuration of at least one of the windings is different from each other, the frequency characteristics of the amplitude of the output voltage with respect to the frequency are different from each other .

The current sensor according to claim 2 is the current sensor according to claim 1. In the current sensor according to claim 1, the plurality of Rogowski coils are formed along the length direction of the sensor body and over almost the entire area of the sensor body. a common of the core disposed within the winding of the same number as the Rogowski coil is formed are formed separately.

The current sensor according to claim 3 is the current sensor according to claim 1. In the current sensor according to claim 1, the plurality of Rogowski coils are formed on the sensor main body along the length direction of the sensor main body and over substantially the entire area of the sensor main body. the windings are configured individually formed on each of the arranged has been the Rogowski coil and the same number of individual of said core within.

The current detection device according to claim 4 is individually connected to the current sensor according to any one of claims 1 to 3 and the plurality of Rogowski coils, and is located between both ends of the connected Rogowski coils. It is provided with the same number of detection circuits as the Rogowski coil that outputs a detection voltage having an amplitude corresponding to the amplitude of the current to be detected based on the generated induced electromotive force.

The current detecting device according to claim 5 includes an adding circuit that adds and outputs the detection voltages output from the plurality of detection circuits in the current detecting device according to claim 4.

According to the current sensor according to the first aspect and the current detection device according to the fourth aspect, a plurality of Rogowski coils having different frequency characteristics of the amplitude of the output voltage with respect to the frequency are formed along the length direction of the sensor body and the sensor. By arranging them in the sensor main body over almost the entire area of the main body, the detection frequency band of the current sensor as a whole and the detection frequency band of the current detection device as a whole can be set as the detection frequency when one Rogoski coil is used. It can be one frequency band that is sufficiently wide as compared with the band, or can be configured by a plurality of different frequency bands (wider frequency band as a whole). Therefore, according to this current sensor and current detector, for example, the detection target current over a wide frequency band centered on the fundamental wave component can be detected with sufficient accuracy, and the frequency of the fundamental wave component changes with time. It is possible to keep detecting the current to be detected (shifting to one of a plurality of frequency bands) at all times.

In the current sensor according to claim 2 and the current detection device according to claim 4 provided with this current sensor, a plurality of Rogowski coils are provided along the length direction of the sensor body and over almost the entire area of the sensor body. a common core disposed within the sensor body (one core), Rogowski coils and the same number of windings are configured individually formed. Therefore, according to this current sensor and the current detection device, in the manufacturing process, it is only necessary to dispose one winding core in which a plurality of windings are formed in the sensor main body, so that the efficiency of the manufacturing work can be improved. Can be done.

In the current sensor according to claim 3 and the current detection device according to claim 4 provided with this current sensor, each Rogowski coil is a sensor along the length direction of the sensor body and over almost the entire area of the sensor body. A winding is individually formed on each of the same number of individual winding cores as the Rogowski coil arranged in the main body. Therefore, according to this current sensor and current detection device, the length, cross-sectional shape and cross-sectional area of each winding core can be made uniform, and at least one of the length, cross-sectional shape and cross-sectional area of each winding core can be different. Since the degree of freedom in design can be increased, it is possible to provide (realize) a current sensor and a current detection device having a desired frequency characteristic (desired detection frequency band).

According to the current detection device according to claim 4, each detection voltage having an amplitude corresponding to the amplitude of the current to be detected (with each Rogowski coil having different frequency characteristics) without preparing a separate integrator (integrator) or the like. Each detection voltage composed of the detected frequency components) can be output with high accuracy.

According to the current detection device according to claim 5, a detection voltage having an amplitude corresponding to the amplitude of the current to be detected (composed of each frequency component detected by a plurality of Rogowski coils) without preparing a separate adder or the like. The detected voltage) can be output with high accuracy.

It is a block diagram of the current detection device 1A provided with the current sensor 2A. It is a block diagram of the current detection device 1B provided with the current sensor 2B. It is a frequency characteristic diagram of the current detection devices 1A and 1B. It is another frequency characteristic diagram of the current detection devices 1A and 1B.

Hereinafter, embodiments of the current sensor and the current detection device will be described with reference to the accompanying drawings.

First, the configuration of the current detection device including the current sensor will be described with reference to the drawings.

First, the configuration of the current detection device 1A as the current detection device shown in FIG. 1 will be described.

The current detection device 1A includes a current sensor 2A and a signal processing unit 3, and detects the detection target current I flowing in the current path 11 (specifically, according to (proportional to) the amplitude of the detection target current I). Outputs the amplitude detection voltage Vi).

The current sensor 2A includes a sensor main body 21 formed in an annular shape that can surround the current path 11, and a plurality of Rogowski coils arranged in the sensor main body 21 (in this example, the first Rogowski coil 22 is an example. It is equipped with two of the second logo ski coils 23). In this case, the sensor body 21 is formed of, for example, a hollow annular body using a non-magnetic material having electrical insulation. The sensor body 21 may be formed in advance as an annular body, or may be formed in advance as a flexible rod-shaped body, and one end of the sensor body 21 may be fixed close to the other end to form an annular body. It may be formed as. Further, the sensor main body 21 includes a configuration formed in a case shape capable of accommodating a plurality of Rogovski coils, and an insulating coating formed on the outer periphery of the plurality of Rogovski coils to integrate each Rogovski coil. Is also included.

As an example, the first Rogovski coil 22 includes a winding core 22a, a winding 22b, a rewinding wire 22c, and a set of output wires 22d and 22e.

The winding core 22a is formed in a rod shape having a uniform cross-sectional shape (and thus a uniform cross-sectional area) using a non-magnetic material having electrical insulating properties and flexibility (for example, silicone rubber). Further, the cross-sectional shape of the winding core 22a can be various shapes such as a polygon such as a circle and a quadrangle, or an ellipse. Further, the winding core 22a is formed to have a length covering almost the entire area of the sensor main body 21.

The winding 22b is composed of, for example, a wire whose surface is covered with an insulating coating (for example, an enamel copper wire; a wire shown by a thin wire in FIG. 1), and has a substantially uniform pitch (gap) on the outer peripheral surface of the winding core 22a. , It is formed by spirally winding (the number of windings is N1) from one end P1 of the winding core 22a to the other end P2 (that is, over the entire winding core 22a). The winding 22b may be formed by winding a lead wire in a single-layer structure, or may be formed by winding a lead wire in a multi-layer structure. Further, the end of the lead wire forming the winding 22b on the P1 side is connected to the output electric wire 22d.

The unwinding wire 22c is composed of a conducting wire, and in this example, as an example, a state in which the winding core 22a penetrates the central portion of the winding core 22a (from the end surface of one end P1 of the winding core 22a to the other end P2). It is arranged in a state over the end face of. Further, as an example, the rewind wire 22c has one end protruding from the end surface of one end P1 of the winding core 22a connected to the output wire 22e and protruding from the other end surface P2 of the winding core 22a. The end is connected to the other end P2 side of the lead wire constituting the winding 22b.

As an example, the second Rogovski coil 23 includes a winding core 22a (common with the first Rogovski coil 22), a winding 23b, a rewinding wire 23c, and a set of output wires 23d and 23e, other than the winding 23b. The configuration of is almost the same as that of the first Rogovski coil 22.

The winding 23b is composed of, for example, a conducting wire of the same type as the winding 22b (the conducting wire shown by the thick wire in FIG. 1), and has a pitch (gap) substantially equal to the outer peripheral surface of the winding core 22a, and one end of the winding core 22a. It is formed by spirally winding (the number of windings is N2 times (<N1 times)) from the portion P1 to the other end portion P2 (that is, over the entire winding core 22a). The winding 23b may be formed by winding a lead wire in a single-layer structure, or may be formed by winding a lead wire in a multi-layer structure. Further, the end of the lead wire forming the winding 23b on the P1 side is connected to the output electric wire 23d.

The unwinding wire 23c is composed of a conducting wire, and in this example, as an example, a state in which the winding core 22a penetrates the central portion of the winding core 22a (from the end surface of one end P1 of the winding core 22a to the other end P2). It is arranged in a state over the end face of. Further, as an example, the rewind wire 23c has one end protruding from the end surface of one end P1 of the winding core 22a connected to the output wire 23e and protruding from the other end surface P2 of the winding core 22a. The end is connected to the other end P2 side of the lead wire constituting the winding 23b. In this example, the rewind wire 23c is separated from the rewind wire 22c, but it can be shared.

The first Rogovski coil 22 and the second Rogovski coil 23 (that is, the respective Rogovski coils 22 and 23) formed in common with the winding core 22a in this way are formed to have substantially the same length as the sensor body 21. As shown in FIG. 1, the sensor main body 21 is in the circumferential direction (also in the length direction. When the sensor main body 21 is a rod-shaped body, the length direction). It is arranged in the sensor main body 21 along the same line and so as to cover almost the entire area of the sensor main body 21.

Further, in the first Rogovski coil 22 and the second Rogovski coil 23, since the winding 22b and the winding 23b are formed on a common winding core 22a, the average magnetic path length and cross-sectional area of the coils are substantially equal to each other. equal. On the other hand, the number of turns (N1) of the winding 22b of the first Rogovski coil 22 is larger than the number of turns (N2) of the winding 23b of the second Rogovski coil 23. Due to this difference in the number of turns, the first Rogowski coil 22 has a frequency characteristic in which the detection frequency band is shifted to a lower frequency side with the detection frequency band of the second Rogowski coil 23 as a reference (that is, the second Rogowski coil 23). It has a frequency characteristic different from that of the coil 23).

As shown in FIG. 1 as an example, the signal processing unit 3 includes a first detection circuit 31, a second detection circuit 32, and an addition circuit 33.

The first detection circuit 31 includes an integrating circuit 31a, a gain adjusting amplifier 31b, and a low-pass filter (LPF) 31c, and has a voltage V1 output from between the pair of output wires 22d and 22e of the first Rogowski coil 22. (The first induced electromotive voltage V1 generated between both ends of the first Rogowski coil 22) is input, and each frequency component included in this voltage V1 (included in the detection frequency band mainly detected by the first Rogowski coil 22). The level of each frequency component) is adjusted to a constant level and output as the first detection voltage V1o.

The first Rogowski coil 22 has a configuration (that is, a configuration that functions as a differentiating circuit) that outputs a voltage V1 proportional to a change over time with respect to a detection target current I whose detection frequency band includes a frequency component. Therefore, in the first detection circuit 31, the integrating circuit 31a having a frequency characteristic opposite to that of the differentiating circuit inputs the voltage V1 and uniformly aligns the levels of the frequency components contained in the voltage V1 to the voltage V1a. Output as. In this example, as an example, as shown in FIG. 1, the integrating circuit 31a adopts a configuration in which a voltage V1 is input when the potential of the output wire 22e is set to the reference potential (ground potential G) of the signal processing unit 3. Although not shown, it is also possible to adopt a configuration in which the voltage V1 is input when the potential of the output electric wire 22d is set as the reference potential (ground potential G).

The gain adjustment amplifier 31b inputs the voltage V1a, amplifies it with the adjusted gain, and outputs it as the voltage V1b. By adjusting the gain of the gain adjustment amplifier 31b, the gain of the entire detection system composed of the first Rogowski coil 22 and the first detection circuit 31 can be obtained by the second Rogowski coil 23 and the second detection. It is possible to match the gain of the detection system composed of the circuit 32 as a whole. The LPF 31c passes a frequency component (main frequency component constituting the voltage V1) included in the detection frequency band of the first Rogowski coil 22 and is included in a frequency range higher than the detection frequency band of the first Rogowski coil 22. The frequency component (component that becomes noise for the voltage V1) is removed and output as the first detection voltage V1o.

In this way, the first detection circuit 31, in combination with the first Rogowski coil 22, for example, in the detection frequency band RG1 having the frequency f1 as the lower limit frequency and the frequency f2 as the upper limit frequency, as shown in FIG. It is possible to accurately detect the detection target current I including the frequency component and output the first detection voltage V1o having an amplitude corresponding to the amplitude of the detection target current I with high accuracy. In this case, the lower limit frequency f1 is mainly defined based on the frequency characteristics of the first Rogovski coil 22, and the upper limit frequency f2 is defined based on the cutoff frequency of the LPF 31c as described above.

The second detection circuit 32 includes an integrating circuit 32a, an amplifier 32b, and a high-pass filter (HPF) 32c, and has a voltage V2 (second) output from between the pair of output wires 23d and 23e of the second Rogowski coil 23. 2 The second induced electromotive voltage V2 generated between both ends of the Rogowski coil 23 is input, and each frequency component included in this voltage V2 (each included in the detection frequency band mainly detected by the second Rogowski coil 23). The level of the frequency component) is adjusted to a constant level and output as the second detection voltage V2o.

Like the first Rogowski coil 22, the second Rogowski coil 23 also outputs a voltage V2 proportional to the temporal change of the detection target current I whose detection frequency band includes a frequency component (that is,). It is a configuration that functions as a differentiating circuit). Therefore, even in the second detection circuit 32, the integrating circuit 32a having the frequency characteristic opposite to that of the differentiating circuit inputs the voltage V2, and the levels of the frequency components contained in the voltage V2 are uniformly aligned to the voltage V2a. Output as. In this example, as an example, as shown in FIG. 1, the integrating circuit 32a adopts a configuration in which a voltage V2 is input when the potential of the output wire 23e is set to the reference potential (ground potential G) of the signal processing unit 3. However, although not shown, it is also possible to adopt a configuration in which the voltage V2 is input when the potential of the output wire 23d is set as the reference potential (ground potential G).

The amplifier 32b inputs the voltage V2a, amplifies it with a predetermined gain, and outputs it as the voltage V2b. The HPF 32c passes a frequency component (main frequency component constituting the voltage V2) included in the detection frequency band of the second Rogowski coil 23, and is included in a frequency range lower than the detection frequency band of the second Rogowski coil 23. The frequency component (component that becomes noise for the voltage V2) is removed and output as the second detection voltage V2o.

In this way, the second detection circuit 32, in combination with the second Rogowski coil 23, for example, has a frequency f3 (≧ f2) as the lower limit frequency and a frequency f4 as the upper limit frequency, as shown in FIG. It is possible to accurately detect the detection target current I including the frequency component in the frequency band RG2 and output the second detection voltage V2o having an amplitude corresponding to the amplitude of the detection target current I with high accuracy. .. In this case, the lower limit frequency f3 is defined based on the cutoff frequency of the HPF 32c as described above, and the upper limit frequency f4 is defined based on the frequency characteristic of the second Rogowski coil 23 or the frequency characteristic of the amplifier 32b.

The addition circuit 33 adds the first detection voltage V1o output from the first detection circuit 31 and the second detection voltage V2o output from the second detection circuit 32, and outputs the detection voltage Vi. Therefore, the frequency characteristics of the current detection device 1A as a whole are the frequency characteristics of the first Rogowski coil 22 and the first detection circuit 31 as a whole, and the frequency of the second Rogowski coil 23 and the second detection circuit 32 as a whole. The frequency characteristics are combined with the characteristics.

Therefore, as shown in FIG. 3, the gain (gain) of the first Rogowski coil 22 and the first detection circuit 31 as a whole and the gain (gain) of the second Rogowski coil 23 and the second detection circuit 32 as a whole. The cutoff frequency on the high frequency side of the detection frequency band RG1 on the 1st Rogowski coil 22 side (upper limit frequency f2 of the detection frequency band RG1) and the low frequency of the detection frequency band RG2 on the 2nd Rogowski coil 23 side. By matching the cutoff frequency on the side (lower limit frequency f3 of the detection frequency band RG2) (f3 = f2), the frequency characteristics of the current detection device 1A as a whole are shown by a single point chain line (lower limit frequency is f1). Therefore, it is possible to set the upper limit frequency to a wide detection frequency band (RG1 + RG2) frequency characteristic of f4).

Further, as shown in FIG. 4, the gain (gain) of the first Rogowski coil 22 and the first detection circuit 31 as a whole and the gain (gain) of the second Rogowski coil 23 and the second detection circuit 32 as a whole. The cutoff frequency on the high frequency side of the detection frequency band RG1 on the first Rogowski coil 22 side (the upper limit frequency f2 of the detection frequency band RG1) of the detection frequency band RG2 on the second Rogowski coil 23 side. By shifting the cutoff frequency on the low frequency side (lower limit frequency f3 of the detection frequency band RG2) to the high frequency side (f3> f2), the frequency characteristics of the current detection device 1A as a whole are shown by a single point chain line (frequency characteristics). A frequency characteristic having two separated detection frequency bands, that is, a detection frequency band RG1 having a lower limit frequency of f1 and an upper limit frequency of f2 and a detection frequency band RG2 having a lower limit frequency of f3 and an upper limit frequency of f4. However, it is also possible to make the frequency characteristics of a wide detection frequency band as a whole).

Next, the operation of the current detection device 1A will be described.

In this current detection device 1A, as shown in FIG. 1, a state in which the sensor main body 21 formed in an annular shape is attached to the current path 11 so as to surround the current path 11 (arranged in the sensor main body 21 and is annular). In the state where the current path 11 penetrates the inside of each of the Rogowski coils 22 and 23 formed in the above), in each of the Rogowski coils 22 and 23, the respective windings 22b and 23b have the current to be detected in the current path 11 The magnetic field (not shown) generated around the current path 11 due to the flow of the current is detected, the respective voltages V1 and V2 are generated, and the current is output to the corresponding detection circuits 31 and 32.

The first detection circuit 31 generates a first detection voltage V1o composed of frequency components included in the detection frequency band RG1 based on the voltage V1 output from the first Rogowski coil 22, and outputs the first detection voltage V1o to the addition circuit 33. To do. Further, the second detection circuit 32 generates a second detection voltage V2o composed of frequency components included in the detection frequency band RG2 based on the voltage V2 output from the second Rogowski coil 23, and the addition circuit 33. Output to. The adder circuit 33 adds the detection voltages V1o and V2o to output a detection voltage Vi composed of a frequency component included in the detection frequency band RG1 and a frequency component included in the detection frequency band RG2.

As a result, the current detection device 1A is configured with the first logoski coil 22 and the first detection circuit 31 so that the different detection frequency bands RG1 and RG2 have the relationship shown in FIG. When the ski coil 23 and the second detection circuit 32 are configured (when the detection system of the Rogowski coil and the detection circuit is multiple systems (two systems in this example)), the detection system of the Rogowski coil and the detection circuit The device as a whole is provided with a sufficiently wide continuous detection frequency band (RG1 + RG2) as compared with the detection frequency band when there is only one system. Therefore, in the current detection device 1A having this configuration, the detection target current I that could not be detected with sufficient accuracy in the detection frequency band when the detection system of the Rogowski coil and the detection circuit is one system, for example, a rectangular shape Sufficient accuracy (more) for the detection target current I whose frequency components spread over a wide frequency band centering on the fundamental wave component, such as the detection target current I composed of waveforms. It is possible to detect with high accuracy).

On the other hand, in the current detection device 1A, the first Rogowski coil 22 and the first detection circuit 31 are configured and the second Rogowski so that the different detection frequency bands RG1 and RG2 have the relationship shown in FIG. When the coil 23 and the second detection circuit 32 are configured, the width of each detection frequency band RG1 and RG2 is larger than that when the detection system of the Rogowski coil and the detection circuit is one system. Although it is not so wide, it is possible to accurately detect the detection target current I whose frequency components are included in the different detection frequency bands RG1 and RG2. Therefore, in the current detection device 1A having this configuration, for example, with respect to the detection target current I whose frequency (fundamental frequency) of the fundamental wave component changes with time, the change is in one of the detection frequency bands RG1 and RG2. When the change includes, the detection target current I can always be continuously detected.

As described above, according to the current sensor 2A and the current detection device 1A provided with the current sensor 2A, a plurality of Rogowski coils having different frequency characteristics (in this example, the Rogowski coils 22, By arranging the two) of 23) along the length direction (circumferential direction) of the sensor body 21 and over almost the entire area of the sensor body 21, the detection frequency band and current of the current sensor 2A as a whole are detected. The detection frequency band of the detection device 1A as a whole may be set to one sufficiently wide frequency band or a plurality of different frequency bands as compared with the detection frequency band when the detection system of the Rogowski coil and the detection circuit is one system. (Overall, a wider frequency band) can be configured. Therefore, according to the current sensor 2A and the current detection device 1A, the detection target current I over a wide frequency band centered on the fundamental wave component can be detected with sufficient accuracy, and the frequency of the fundamental wave component changes with time. It is possible to keep detecting the changing target current I (shifting to one of a plurality of different frequency bands) at all times.

Further, according to the current detection device 1A, a plurality of detection circuits (in this example, the Rogowski coils 22 and 23) corresponding to a plurality of Rogowski coils (two of the Rogowski coils 22 and 23 in this example) are used, respectively. By providing the corresponding detection circuits 31 and 32), the respective detection voltages V1o and V2o (different frequency characteristics) having an amplitude corresponding to the amplitude of the detection target current I can be obtained without separately preparing an integrator (integrator) or the like. Each detection voltage composed of frequency components detected by the Rogowski coils 22 and 23) can be output with high accuracy. Further, according to the current detection device 1A, since the adder circuit 33 is provided, the detection voltage Vi (each Rogowski coil) having an amplitude corresponding to the amplitude of the current I to be detected does not need to be prepared separately. The detection voltage composed of each frequency component detected in 22 and 23) can be output with high accuracy.

Further, in the current sensor 2A and the current detection device 1A provided with the current sensor 2A, the Rogowski coils 22 and 23 extend along the length direction of the sensor body 21 and cover almost the entire area of the sensor body 21. A common winding core 22a (one winding core) arranged in the sensor main body 21 is individually formed with the same number of windings 22b and 23b as the Rogowski coils 22 and 23. Therefore, according to the current sensor 2A and the current detection device 1A, in the manufacturing process, it is only necessary to dispose one winding core 22a on which the windings 22b and 23b are formed in the sensor main body 21, and thus the manufacturing work Efficiency can be improved.

In the above current sensor 2A, the same number of windings 22b and 23b as the Rogowski coils 22 and 23 are individually formed on a common winding core (winding core 22a) to form the Rogowski coils 22 and 23. , As in the current sensor 2B shown in FIG. 2, the Rogowski coils 22 and 23 can be configured by using the individual winding cores 22a and 23a.

Hereinafter, the current sensor 2B and the current detection device 1B provided with the current sensor 2B will be described. The current sensor 2B and the current detection device 1B constitute the Rogowski coils 22 and 23 using the individual winding cores 22a and 23a as described above as compared with the current sensor 2A and the current detection device 1A. It differs only in that it does, and is the same for other configurations. The operation is also the same. Therefore, the different configurations will be mainly described, and the same configurations will be designated by the same reference numerals and the description thereof will be omitted.

The current detection device 1B includes a current sensor 2B and a signal processing unit 3 and detects a detection target current I flowing in the current path 11 (outputs a detection voltage Vi having an amplitude corresponding to the amplitude of the detection target current I). ..

The current sensor 2B includes a sensor main body 21 and a plurality of Rogowski coils (two, a first Rogowski coil 22 and a second Rogowski coil 23, as an example in this example) arranged in the sensor main body 21. I have.

As an example, the first Rogovski coil 22 includes a winding core 22a, a winding 22b, a rewinding wire 22c, and a set of output wires 22d and 22e.

The winding core 22a is formed in a rod shape having a uniform cross-sectional shape (and thus a uniform cross-sectional area) using a non-magnetic material having electrical insulating properties and flexibility (for example, silicone rubber). Further, the winding core 22a is formed to have a length covering almost the entire area of the sensor main body 21. The winding 22b has a pitch (gap) substantially equal to the outer peripheral surface of the winding core 22a from one end P1 of the winding core 22a to the other end P2 (that is, over the entire winding core 22a). ) It is formed by spirally winding (the number of windings is N1). Further, the end of the lead wire forming the winding 22b on the P1 side is connected to the output electric wire 22d. The unwinding wire 22c is arranged in a state in which the winding core 22a penetrates the central portion of the winding core 22a (a state extending from the end surface of one end P1 of the winding core 22a to the end surface of the other end P2). .. Further, as an example, the rewind wire 22c has one end protruding from the end surface of one end P1 of the winding core 22a connected to the output wire 22e and protruding from the other end surface P2 of the winding core 22a. The end is connected to the other end P2 side of the lead wire constituting the winding 22b.

As an example, the second Rogovski coil 23 includes a winding core 23a (separate from the winding core 22a), a winding 23b, a rewinding wire 23c, and a set of output wires 23d and 23e.

The winding core 23a may be a non-magnetic material having electrical insulation and flexibility (for example, silicone rubber, etc., which may be the same material as the winding core 22a, or another material having the same characteristics. Good. In this example, the same material is used as an example) to form a rod having a uniform cross-sectional shape (and therefore a uniform cross-sectional area). Further, the winding core 23a is formed to have a length covering almost the entire area of the sensor main body 21. The winding 23b has a pitch (gap) substantially equal to the outer peripheral surface of the winding core 23a from one end P3 of the winding core 23a to the other end P4 (that is, over the entire winding core 23a). ) It is formed by spirally winding (the number of windings is N2 times). Further, the end of the lead wire forming the winding 23b on the P3 side is connected to the output wire 23d. The unwinding wire 23c is arranged in a state in which the winding core 23a penetrates the central portion of the winding core 23a (a state extending from the end surface of one end P3 of the winding core 23a to the end surface of the other end P4). .. Further, as an example, the rewind wire 23c has one end protruding from the end surface of one end P3 of the winding core 23a connected to the output wire 23e and protruding from the other end surface P4 of the winding core 23a. The end is connected to the other end of the lead wire forming the winding 23b on the P4 side.

As shown in FIG. 2, the first Rogowski coil 22 formed on the winding core 22a and the second Rogowski coil 23 formed on the winding core 23a are the circumferences of the sensor body 21 when they are annular. They are arranged in the sensor body 21 along the direction (also in the length direction. When the sensor body 21 is a rod-shaped body, the length direction thereof) and so as to cover almost the entire area of the sensor body 21 ( That is, the Rogowski coils 22 and 23 are formed to have substantially the same length as the sensor body 21 and are integrally formed). The first Rogovski coil 22 and the second Rogovski coil 23 may be arranged in a twisted state or may be arranged in a non-twisted state.

Further, in the first Rogowski coil 22 and the second Rogowski coil 23, since the winding cores 22a and 23a are individual (separate bodies), the material (dielectric constant), length, and cross-sectional shape of the winding cores 22a and 23a are different. And the cross-sectional area can be aligned, and at least one of the material (its dielectric constant), length, cross-sectional shape and cross-sectional area can be different. It is also possible to make the number of turns of the winding 22b (N1) and the number of turns of the winding 23b (N2) uniform or different. In this example, as an example, for the winding cores 22a and 23a, the material, length, cross-sectional shape and cross-sectional area are aligned, and for the number of turns (N1) and the number of turns (N2), the number of turns (N1) is set as the number of turns (N1). The configuration is more than N2). Due to this difference in the number of turns, as shown in FIG. 3 or 4, the first Rogowski coil 22 has a detection frequency band RG1 on the lower frequency side with reference to the detection frequency band RG2 of the second Rogowski coil 23. It has a frequency characteristic shifted to (that is, a frequency characteristic different from the frequency characteristic of the second Rogowski coil 23).

As described above, according to the current sensor 2B and the current detection device 1B provided with the current sensor 2B, a plurality of Rogowski coils having different frequency characteristics (in this example, the Rogowski coils 22, By disposing the two) of 23) along the length direction of the sensor main body 21 and over almost the entire area of the sensor main body 21, the same effect as that of the above-mentioned current sensor 2A and current detection device 1A can be obtained. be able to.

Further, in the current sensor 2B and the current detection device 1B, the Rogovski coils 22 and 23 have windings 22b and 23b individually attached to the same number of individual winding cores 22a and 23a as the Rogovski coils 22 and 23, respectively. It is formed and constructed. With this configuration, according to the current sensor 2B and the current detection device 1B, the length, cross-sectional shape and cross-sectional area of the winding cores 22a and 23a can be made uniform, or at least one of the length, cross-sectional shape and cross-sectional area can be set. Since it is possible to increase the degree of freedom in design such as being able to make a difference, it is possible to provide a current sensor and a current detection device having a desired frequency characteristic (desired detection frequency band).

Further, in the signal processing unit 3, the gain adjustment amplifier is connected to the first detection circuit 31 connected to the first Rogowski coil 22 having a lower detection frequency band among the first detection circuit 31 and the second detection circuit 32. Although the configuration in which 31b is arranged is adopted, the amplifier 32b of the second detection circuit 32 can also be a gain adjustment type amplifier, and conversely, it is connected to the second Rogowski coil 23 having a high detection frequency band. It is also possible to adopt a configuration in which only the amplifier on the side of the second detection circuit 32 is a gain adjustment type.

Further, the above-mentioned current sensors 2A and 2B adopt a configuration in which the winding times N1 and N2 of the windings 22b and 23b are different in order to make the frequency characteristics of the Rogowski coils 22 and 23 different. In the current sensor 2B using the winding cores 22a and 23a, the material of the winding cores 22a and 23a (the dielectric thereof) is replaced with a configuration in which the winding times N1 and N2 are different, or in addition to a configuration in which the winding times N1 and N2 are different. A configuration that differs at least one of rate), length, cross-sectional shape, and cross-sectional area may be adopted to make the frequency characteristics different.

Further, in the above-mentioned current detection devices 1A and 1B, by adjusting the gain of the gain adjustment amplifier 31b, the gain of the detection system composed of the first Rogowski coil 22 and the first detection circuit 31 and the gain of the second Rogowski A preferable configuration is adopted in which the gains of the detection systems composed of the coil 23 and the second detection circuit 32 are aligned, but if necessary, a configuration in which the gains of the above two detection systems are different may be adopted. it can.

Further, the above-mentioned current sensors 2A and 2B adopt a configuration in which two Rogowski coils 22 and 23 having different frequency characteristics are arranged in the sensor main body 21, but the logo is arranged in the sensor main body 21. The number of ski coils (logo ski coils having different frequency characteristics from each other) is not limited to two, and can be any number such as three or four. In this case, the number of detection circuits constituting the signal processing unit 3 shall match the number of Rogovski coils. Further, each of the current sensors 2A and 2B described above employs a preferable configuration in which the addition circuit 33 is included in the signal processing unit 3 to save the trouble of separately preparing the addition device. It is also possible to adopt a configuration in which the above is not included in the signal processing unit 3 (a configuration in which the addition circuit 33 is provided separately from the signal processing unit 3).

1A, 1B Current detector 11 Current path 21 Sensor body 22,23 Rogowski coil 22a, 23a Winding core 22b, 23b Winding 31, 32 Detection circuit V1, V2 Voltage V1o, V2o Detection voltage

Claims (5)

The sensor body formed in an annular shape that can surround the current path of the current to be detected,
Together configured windings are formed in the winding core, the sensor along the length of the body, and multiple Rogowski that will be respectively disposed within the sensor body over substantially the entire area of the sensor body Equipped with a coil ,
The plurality of Rogovski coils are current sensors in which the frequency characteristics of the amplitude of the output voltage with respect to the frequency are different from each other because the configuration of at least one of the winding core and the winding is different from each other . Wherein the plurality of Rogowski coils, along the length of the sensor body, and the common of the winding core which is disposed within the sensor body over substantially the entire area of the sensor body, and the Rogowski coil The current sensor according to claim 1, wherein the same number of windings are individually formed. Wherein the plurality of Rogowski coils, the sensor along the length of the body, and the Rogowski coil and the same number of individual said winding core which is disposed within the sensor body over substantially the entire area of the sensor body The current sensor according to claim 1, wherein the windings are individually formed in each of the above . The current sensor according to any one of claims 1 to 3 and
The plurality of Rogowski coils are individually connected to each other, and a detection voltage having an amplitude corresponding to the amplitude of the current to be detected is output based on an induced electromotive voltage generated between both ends of the connected Rogowski coils. A current detector with the same number of detection circuits as the Rogowski coil. The current detection device according to claim 4, further comprising an adder circuit that adds and outputs the detection voltages output from the plurality of detection circuits.

Images