JP6362414B2 - Current sensor and measuring device - Google Patents

Description

  The present invention relates to a current sensor that outputs a detection current whose current value changes in accordance with the current value of an alternating current that flows through a conductor to be measured, and a measuring apparatus that includes this current sensor.

  As this type of current sensor, a current sensor (CT: current transformer) disclosed in Patent Document 1 below is known. As shown in FIG. 7, the current sensor 51 has a semicircular shape by arranging a semicircular one-side small-diameter core piece 52b inside a semicircular one-side large-diameter core piece 52a. The semi-circular other-side small-diameter core piece portion 53b is disposed inside the semi-circular other-side large-diameter core piece portion 53a and formed into a semi-circular shape as a whole. The other core portion 53 and the winding 54 are provided. In this current sensor 51, the one core part 52 and the other core part 53 are connected to form an annular core RC into which the measurement target conductor 61 is inserted. The winding 54 is divided into a winding 54a wound around one core portion 52 and a winding 54b wound around the other core portion 53, and the two windings 54a, 54b. Are connected in series. In this type of normal current sensor (a current sensor formed by winding a winding around an annular core), each core portion constituting each annular core RC (each core portion 52 in the current sensor 51, 53) are each composed of one core material.

  In this current sensor 51, a detection current Id whose current value changes according to the current value of the alternating current I flowing in the conductor to be measured 61 inserted into the annular core constituted by the core portions 52 and 53 is wound. 54. Therefore, according to the current sensor 51, the current value of the alternating current I can be measured based on the voltage signal Vi by converting the detected current Id into the voltage signal Vi by the current-voltage converter 55. It is possible.

JP 2007-57294 A (pages 7-8, FIG. 5)

  By the way, in this type of current sensor, the frequency band of the sensitivity is a resonance frequency (f = 1 / 2π) defined by the inductance value L of the winding and the capacitance value C of the parasitic capacitance (interline capacitance) of the winding. The upper limit side (high frequency side) is limited by √ (L · C)). Specifically, like the current sensor 51, a plurality of core parts (two core parts 52 and 53 in the above example) are connected to form an annular core, and the winding is divided into each core part. In the current sensor configured to be wound, the magnetic resistance at the bonded portion of each core portion (the portion indicated by the symbol X in FIG. 7) is larger than the magnetic resistance of the core portion itself (the bonded portion). Since each core part is connected in a weak magnetic coupling state due to the presence of X), the equivalent circuits of the windings 54a and 54b wound around the respective core parts 52 and 53 are as follows: When the inductance value of each of the windings 54a and 54b is L1, and the capacitance value of the parasitic capacitance of each of the windings 54a and 54b is C1, respectively, a coil having an inductance value L1 and a capacitance value C1 connected in parallel to this coil Condens Represented by the LC circuit composed of a.

  Therefore, the equivalent circuit of the entire winding 54 configured by connecting the windings 54a and 54b in series is equivalent to the number of the cores of the above-described LC circuit (the windings of the windings divided into the cores). It will be connected in series (only a few minutes). For this reason, as shown in FIG. 8, the frequency characteristic of the sensitivity of the current sensor 51 includes an inductance value L1 of the winding wound around one core portion and a capacitance value C1 of the parasitic capacitance of this winding. The upper limit is limited by the resonance frequency (f1 = 1 / 2π√ (L1 · C1)) defined by. That is, the current sensor 51 can measure the alternating current I up to the frequency f1.

  However, as the alternating current I flowing through the conductor 61 to be measured is increased in frequency, there is a demand for measuring the alternating current I having a higher frequency. In this case, it is preferable that this request can be met by a simple configuration change of the current sensor.

  The present invention has been made in view of such a demand, and a main object of the present invention is to provide a current sensor that can detect an alternating current having a higher frequency by a simple configuration change. Another main object is to provide a measuring apparatus including the current sensor.

  In order to achieve the above object, the current sensor according to claim 1 has a ring core in which a plurality of core portions are connected and configured in an annular shape, and a conductor to be measured is inserted therein, and a predetermined number of turns. a plurality of windings wound around each of the plurality of core portions by n (n is an integer of 2 or more), and all the windings wound around the plurality of core portions are the same The windings wound around the core part are connected in series with the windings wound around the other core part interposed.

  The current sensor according to claim 2, wherein in the current sensor according to claim 1, all the windings are arranged in a circumferential direction of the annular core among the n windings wound around the core portions. The j-th windings (j is an integer of 1 or more and n or less) from the same one side are connected in series to form n series windings, and the n series windings are: They are connected in series as a whole.

  According to a third aspect of the present invention, there is provided the current sensor according to the first or second aspect, wherein the current sensor outputs a detection current whose current value changes in accordance with a current value of an alternating current flowing through the conductor to be measured. Yes.

  According to the current sensor of claim 1, n windings are wound around each core portion, and all the windings wound around each core portion are wound around the same core portion. Each winding represented by an equivalent circuit in which a coil and a capacitor are connected in parallel by changing the configuration so that they are connected in series with the windings wound around other cores in between Because the inductance value of this coil and the capacitance value of the capacitor can be reduced respectively, the resonance frequency of the equivalent circuit for each winding that defines the upper limit frequency of the frequency band of this sensitivity while maintaining the detection sensitivity. Can be made higher than the upper limit frequency of the sensitivity frequency band in the conventional configuration in which the windings wound around the same core portion are directly connected and connected in series. It is possible to widen the band to a higher frequency side.

  According to the current sensor of claim 2, the j-th winding from the same one side along the circumferential direction of the annular core among the n windings wound around each core portion is It is possible to manufacture in an easy-to-understand procedure (a procedure with easy-to-understand regularity) in which n series windings are connected in series and the n series windings are connected in series as a whole. Because of the simple structure, the procedure for manufacturing can be easily grasped.

  According to the measuring apparatus of the third aspect, the current value of an alternating current having a higher frequency can be accurately measured by providing the current sensor having the frequency band of sensitivity widened to the high frequency side. At the same time, based on the measured current value, it is possible to accurately measure a physical quantity having a higher frequency for the conductor to be measured.

1 is a configuration diagram showing a configuration of a current sensor 1. FIG. It is a block diagram which shows each structure of the electric power measurement apparatus 31 provided with the electric current sensor 1, the electric current measurement apparatus 21 provided with the electric current sensor 1, and the electric current measurement apparatus 21 and the voltage measurement apparatus 41. It is a top view which shows the structure of 1 A of current sensors. It is a block diagram which shows the structure of 1 A of current sensors. It is a top view which shows the structure of the current sensor 1B. It is a block diagram which shows the structure of the current sensor 1B. 2 is a configuration diagram showing a configuration of a current sensor 51. FIG. It is a frequency characteristic figure about the sensitivity of current sensor 1 and current sensor 51.

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

  First, a configuration of a current sensor 1 as an example of a current sensor will be described with reference to FIGS. The current sensor 1 includes a plurality (m, such as 2, 3, 4, etc.) of core parts (in this example, two core parts 2 and 3 as an example) connected to each other and configured in an annular shape. In the state where the annular core RC through which the measurement target conductor 61 is inserted and the plurality of core portions (core portions 2 and 3 in this example) are separated along the length direction of each core portion, n pieces ( n is a plurality of windings wound (formed) by 2 (an integer of 2 or more such as 2, 3, 4,...) (in this example, 3 (= n) 6 (= 2 × 3) windings 11a, 11b, 11c, 12a, 12b, 12c) wound one by one.

  In addition, all the windings 11a to 12c are formed by using the same type of wire (for example, insulation-coated electric wires) and having the same pitch (for example, dense winding) and the same number of turns (for example, 5 turns). ing. Further, all the windings 11a to 12c have the same one side along the circumferential direction of the annular core RC in the state where the core portions 2 and 3 are configured as the annular core RC. Ends marked with ● are wound. Further, all the windings 11a to 12c are in a state in which the windings wound around other core portions are interposed (in other words, the windings wound around the same core portion are not directly connected to each other). In) connected in series.

  As an example, in the current sensor 1, all the windings 11 a to 12 c are, as shown in FIG. 1, out of 3 (= n) windings wound around the core portions 2 and 3, respectively. The j-th windings (j is an integer from 1 to n) from the same side along the circumferential direction of the annular core RC are connected in series to form n series windings. By connecting the series windings in series as a whole, the series windings are connected in series with the windings wound around the other core part interposed.

  Specifically, as shown in FIGS. 1 and 2, three windings 11 a, 11 b, 11 c wound around the core portion 2, and three windings 12 a wound around the core portion 3. , 12b, 12c, the 1 (= j) -th windings 11a, 12a are connected in series from the same side along the circumferential direction of the annular core RC, and the 2 (= j) -th winding 11b and 12b are connected in series, and 3 (= j) -th windings 11c and 12c are connected in series, and 3 (= n) series windings (11a, 12a), (11b, 12b), (11c, 12c), and the three (= n) series windings (11a, 12a), (11b, 12b), (11c, 12c) are connected in series in this order. Thus, all the windings 11a to 12c are wound around the other core part. State of being interposed are connected in series (winding 11a, 12a, 11b, 12b, 11c, 12c order).

  As described above, all the windings 11a to 12c are arranged along the circumferential direction of the annular core RC among the 3 (= n) windings wound around the core portions 2 and 3, respectively. The configuration in which 3 (= n) series windings are made by connecting the j-th windings from the same one side in series is 3 (= n) wound around each core part 2, 3. Since it is a structure that can be manufactured in an easy-to-understand procedure of connecting individual windings in order from the same side along the circumferential direction of the annular core RC, the combination of windings connected in series is most preferable from the viewpoint of ease of manufacturing. Is not limited to this.

  For example, they may be combined like the series windings (11a, 12b), (11b, 12c), (11c, 12a), or the series windings (11a, 12c), (11b, 12b), (11c, 12a) Any combination is possible as long as the windings wound around the other core part are interposed (the windings wound around the core part are not directly connected). Can be combined. Of course, the order of connection in one set of series windings may be changed. For example, taking the series winding (11a, 12b) as an example, instead of the configuration shown in FIGS. 1 and 2, the windings 12b, 11a may be connected in series (that is, the winding end of the winding 12b). (A portion may be connected in series by connecting the portion to the winding start end of the winding 11a.)

  In the current sensor 1 configured as described above (the current sensor having the configuration shown in FIGS. 1 and 2), as shown in FIG. 1, one output terminal CN1 (in this example) of the pair of output terminals CN1 and CN2 is used. As an example, the winding start end of the winding 11a among all the windings 11a to 12c connected in series is connected to a reference potential (for example, the ground G), and the other output terminal CN2 (in this example) As an example, the end of the winding 12c is connected to the current-voltage conversion unit 22 (in FIG. 1, as an example, a resistor connected between the output terminal CN2 and the reference potential). The detection current Id whose current value changes according to the current value of the alternating current I flowing through the conductor to be measured 61 inserted through the output is output between the output terminals CN1 and CN2. Further, the detection current Id output from the current sensor 1 in this way is converted into a voltage signal Vi whose voltage value is converted in accordance with the current value of the detection current Id in the current-voltage converter 22.

  In this case, compared with the current sensor 51 shown in FIG. 7 described in the background art, the magnetic characteristics of the core portions 52 and 53 and the core portions 2 and 3 (the magnetic material used in the core portion and the annular core The length and cross-sectional area when connected are the same, and the number of turns of the whole windings 54a and 54b and the number of turns of the windings 11a, 11b, 11c, 12a, 12b, and 12c are the same (more specifically, The number of turns of the winding 54a wound around each core part having the same characteristics is the same as the number of turns of the entire windings 11a, 11b, 11c, and the number of turns of the winding 54b is the windings 12a, 12b, 12c (the same as the number of turns of the entire 12c) (that is, the condition that the detection sensitivity of the alternating current I is the same), the current sensor 1 has more winding divisions than the current sensor 51. Lines 54a, 5 The number of turns is smaller than b (that is, the inductance value L2 is smaller than the inductance value L1 of each of the windings 54a and 54b, and the capacitance value C2 of the parasitic capacitance is smaller than the capacitance value C1 of the parasitic capacitance of each of the windings 54a and 54b). ) Each winding 11 a, 11 b, 11 c, 12 a, 12 b, 12 c is in a state where a winding wound around another core portion is interposed (winding around a different core portion with the joint portion X having a large magnetic resistance interposed therebetween) Are connected in series with the windings being directly connected).

  Therefore, an equivalent circuit of the entire windings 11a to 12c of the current sensor 1 includes an LC circuit composed of a coil having an inductance value L2 and a capacitor having a capacitance value C2 connected in parallel to the coil. The number of windings 11a, 11b, 11c, 12a, 12b, and 12c wound in three is connected in series. Therefore, as shown in FIG. 8, the frequency characteristics of the sensitivity of the current sensor 1 include the inductance value L2 (<L1) of each winding 11a, 11b, 11c, 12a, 12b, 12c and the parasitic capacitance of this winding. The upper limit is limited by the resonance frequency (f2 = 1 / 2π√ (L2 · C2)> f1) defined by the capacitance value C2 (<C1). That is, the current sensor 1 is configured to be capable of detecting up to an alternating current I having a higher frequency than the current sensor 51 (a wide frequency band current sensor).

  Next, the configuration of the current measurement device 21 shown in FIG. 2 as an example of the measurement device including the current sensor 1 and the power measurement device 31 shown in FIG. 2 as an example of the measurement device including the current measurement device 21. The configuration of will be described.

  The power measuring device 31 includes a current measuring device 21 and a voltage measuring device 41, and measures the power value W1 of the power W supplied to the measurement target conductor 61.

  The current measuring device 21 is output from the current sensor 1 having one output terminal CN1 connected to the reference potential and between the output terminals CN1 and CN2 of the current sensor 1 (in this example, output from the other output terminal CN2). A current-voltage converter 22 that converts the detection current Id into a voltage signal Vi and outputs the voltage signal Vi; a processing unit 23 that measures the current value I1 of the alternating current I based on the voltage signal Vi; and a measured current value I1 Is output.

  In this case, as shown in FIG. 1, the current-voltage conversion unit 22 can be configured by a resistor connected between the output terminal CN2 and the reference potential. In an arbitrary circuit such as an operational amplifier, which is connected to the output terminal CN2, the non-inverting input terminal is connected to the reference potential, and a current-voltage conversion resistor is connected as a feedback resistor between the inverting input terminal and the output terminal. Can be configured.

  The processing unit 23 is, for example, an A / D converter that converts a voltage signal Vi as an analog signal into a first digital signal, and an A / D converter that converts a voltage signal Vv described later as an analog signal into a second digital signal. And the current value I1 of the alternating current I is calculated based on the first digital signal, the voltage value V1 of the alternating voltage V applied to the conductor 61 to be measured is calculated based on the second digital signal, and the current value A computer that calculates the power value W1 of the power W supplied to the measurement target conductor 61 based on I1 and the voltage value V1 is provided, and functions as a current measurement unit that is a component of part of the current measurement device 21. At the same time, it also functions as a voltage measuring unit that is a part of the voltage measuring device 41 and a power measuring unit that is a part of the power measuring device 31.

  In this example, the output unit 24 includes a display device such as an LCD (Liquid Crystal Display) as an example, and displays the current value I1, the voltage value V1, and the power value W1 measured by the processing unit 23 on the screen. Note that the output unit 24 is not limited to a display device, and may be configured by a transmission device that transmits information (data) to an external device, for example. In this configuration, the output unit 24 outputs the current value I1, the voltage value V1, and the power value W1 measured by the processing unit 23 to an external device.

  The voltage measuring device 41 detects the voltage waveform of the AC voltage V applied to the conductor 61 to be measured in a non-contact manner, and based on the detected voltage waveform, the voltage value V1 of the AC voltage V (reference voltage is used as a reference). Voltage value). In this example, as an example, the voltage measurement device 41 has a known configuration that can detect the voltage waveform of the AC voltage V of the measurement target conductor 61 in a non-contact manner (for example, a voltage detection unit disclosed in Japanese Patent Application Laid-Open No. 2012-137396). And the AC voltage V applied to the measurement target conductor 61 based on the current flowing between the measurement target conductor 61 and the detection electrode 42. And a reference potential signal having the same phase and the same phase (a signal indicating the voltage waveform of the AC voltage V), and the reference potential signal is stepped down to a voltage signal Vv having a voltage value that can be processed by the processing unit 23 in the subsequent stage. Output voltage detector 43, processing unit 23 for measuring voltage value V1 of AC voltage V based on voltage signal Vv, and output unit 24 for outputting measured voltage value V1.

  In addition, although the voltage measurement apparatus 41 described above about the structure which measures the voltage value V1 of the alternating voltage V applied to the measurement object conductor 61 in a non-contact manner, the voltage measurement apparatus 41 is in electrical contact with the measurement object conductor 61. And a probe that makes electrical contact with a reference potential, and measures the voltage value V1 of the AC voltage V by measuring the voltage between both probes (configuration of a contact-type voltage measuring device). You can also

  Next, operations of the current sensor 1, the current measurement device 21, and the power measurement device 31 will be described. The measurement target conductor 61 is inserted into the annular core RC, and the detection electrode 42 is disposed at a certain distance from the measurement target conductor 61 (that is, capacitively coupled to the measurement target conductor 61). ).

  In this state, when an AC voltage V is applied to the measurement target conductor 61 and an alternating current I flows (when electric power W is supplied to the measurement target conductor 61), the current sensor 1 functions as a CT, A detection current Id having an amplitude (current value) corresponding to the ratio of the total number of turns of the windings 11a to 12c to the number of turns of the conductor 61 (for example, 1 turn) is generated in the windings 11a to 12c, and the other output terminal CN2 Output from.

  In the current measuring device 21, the current / voltage conversion unit 22 converts the detected current Id into a voltage signal Vi and outputs the voltage signal Vi to the processing unit 23. On the other hand, in the voltage measuring device 41, the voltage detector 43 detects the AC voltage V applied to the conductor 61 to be measured, and processes the voltage signal Vv having a voltage lower than the AC voltage V and having the same phase. To the unit 23.

  The processing unit 23 calculates the current value I1 of the alternating current I based on the voltage signal Vi, and calculates the voltage value V1 of the alternating voltage V based on the voltage signal Vv. Further, the processing unit 23 calculates a power value W1 of the power W supplied to the measurement target conductor 61 based on the measured current value I1 and voltage value V1. Further, the processing unit 23 outputs the measured current value I1, voltage value V1, and power value W1 to the output unit 24 configured by a display device as an example, and displays it on the screen. The measurement of the current value I1 for the alternating current I by the current measuring device 21 and the measurement of the power value W1 for the power W by the power measuring device 31 provided with the current measuring device 21 are completed.

  Thus, in this current sensor 1, a plurality of core parts (two core parts 2 and 3 as an example) are connected to form an annular core RC, and each core part 2 and 3 is defined in advance. N (three as an example) windings (in this example, windings 11a, 11b, and 11c and windings 12a, 12b, and 12c) are wound (provided), and each core portion 2 and 3 is wound. All the windings 11a, 11b, 11c, 12a, 12b, and 12c that are wound are in a state in which the windings that are wound around other core portions are interposed (in other words, the windings are wound around the same core portion). Are connected in series (with the windings not being directly connected).

  Thereby, in this current sensor 1, the conventional configuration in which the windings wound around the same core portion are directly connected and connected in series (that is, the winding 11a wound around the common core portion 2). 11b, 11c are connected in series with each other in a strong magnetic coupling state, and are represented by an equivalent circuit in which one capacitor having a large inductance value L1 as a whole is connected in parallel to one capacitor having a large capacitance value C1. The windings 12a, 12b, 12c, which are configured as one winding and are wound around the common core portion 3, are connected in series with each other in a strong magnetic coupling state, so that one coil having a large inductance value L1 as a whole. Is configured as one winding represented by an equivalent circuit in which one capacitor having a large capacitance value C1 is connected in parallel, and the winding on the core portion 2 side and the winding on the core portion 3 side are connected in series. The windings 11a, 11b, 11c, 12a, 12b, and 12c are equivalent circuits in which one coil having a smaller inductance value L2 and one capacitor having a smaller capacitance value C2 are connected in parallel. Each of the windings represented is configured and connected in series.

  Therefore, according to the current sensor 1, n (three in this example) windings 11a, 11b, 11c and windings 12a, 12b, 12c are separately wound around each of the core parts 2, 3. The winding 11a, 11b, 11c, 12a, 12b, and 12c are connected in series with the winding wound around the other core portion interposed therebetween. By changing (a very simple configuration change that changes the winding structure of the windings to the cores 2 and 3 and the connection structure of the windings), the frequency band of this sensitivity is maintained while maintaining the detection sensitivity. The resonance frequency f2 (= 1 / 2π√ (L2 · C2)) of the above equivalent circuit for each of the windings 11a, 11b, 11c, 12a, 12b, and 12c that defines the upper limit frequency is wound around the same core portion. The windings that are directly connected Can be made higher than the upper limit frequency f1 (= 1 / 2π√ (L1 · C1)) of the sensitivity frequency band in the conventional configuration connected to the, and thereby the sensitivity frequency band is widened to the high frequency side. be able to.

  Further, according to the current sensor 1, all of the windings 11a, 11b, 11c, 12a, 12b, and 12c are made up of 3 (= n) windings wound around the core portions 2 and 3, respectively. Because of the configuration that can be manufactured in an easy-to-understand procedure (procedure with easy-to-understand regularity) in which j-th windings are connected in series from the same one side along the circumferential direction of the annular core RC, A procedure for manufacturing can be easily grasped.

  Moreover, according to the current measuring device 21 provided with the current sensor 1, the current value I1 can be accurately measured even with respect to the alternating current I having a higher frequency than the configuration provided with the current sensor having the conventional configuration. Can do. Further, according to the power measuring device 31 provided with the current measuring device 21, the power value W1 can be accurately measured even with respect to the alternating current I having a higher frequency.

  In the above example, the two core portions 2 and 3 are connected to form the annular core RC. However, as described above, more core portions such as three and four are connected. The annular core RC may be configured. In the following, as an example, the current sensor 1A in which the three core portions 2, 3, 4 are connected to form the annular core RC and the four core portions 2, 3, 4, 5 are connected to form the annular core RC. A current sensor 1B configured as described above will be described.

  First, the current sensor 1A will be described with reference to FIGS.

  The current sensor 1A includes an annular core RC formed by connecting three core portions 2, 3, and 4 in an annular shape, and each of the core portions 2, 3, and 4 along the length direction of each core portion. In the separated state, n (three in this example) wound windings (9 (= 3 × 3) windings wound three by three on the three core parts 2, 3 and 4) Windings 11a, 11b, 11c, 12a, 12b, 12c, 13a, 13b, 13c) are provided.

  In addition, all the windings 11a to 13c are formed by using the same kind of wire rods and wound at the same pitch and by the same number of turns. In addition, all the windings 11a to 13c are configured so that the same one side along the circumferential direction of the annular core RC has a winding start end portion (FIG. 3, FIG. 3) in a state where the core portions 2, 3 and 4 are configured as the annular core RC. In FIG. 4, it is wound so as to be an end portion marked with ●. Further, all the windings 11a to 13c are in a state in which the windings wound around other core portions are interposed (in other words, the windings wound around the same core portion are not directly connected to each other). In) connected in series.

  As an example, in this current sensor 1A, as shown in FIG. 4, all the windings 11a to 13c are made up of 3 (= n) windings wound around the cores 2, 3, and 4, respectively. The j-th windings (j is an integer from 1 to n) from the same side along the circumferential direction of the annular core RC are connected in series to form n series windings. By connecting the series windings in series as a whole, the series windings are connected in series with the windings wound around the other core part interposed.

  Specifically, as shown in FIG. 4, three windings 11 a, 11 b, 11 c wound around the core part 2, and three windings 12 a, 12 b wound around the core part 3 12c and the 1 (= j) -th winding 11a from the same one side along the circumferential direction of the annular core RC among the three windings 13a, 13b, 13c wound around the core portion 4. , 12a, 13a are connected in series, the 2 (= j) th windings 11b, 12b, 13b are connected in series, and the 3 (= j) th windings 11c, 12c, 13c are connected in series. And 3 (= n) series windings (11a, 12a, 13a), (11b, 12b, 13b), (11c, 12c, 13c), and 3 (= n) Series windings (11a, 12a, 13a), (11b, 12b, 13b), ( 1c, 12c, 13c) are connected in series with each other in this order, so that all the windings 11a to 13c are interposed with the windings wound around the other core portions (winding 11a, 12a, 13a, 11b, 12b, 13b, 11c, 12c, and 13c in this order). In addition, in FIG. 3, illustration of the line segment which shows the wiring which connects each coil | winding 11a-13c is abbreviate | omitted.

  Also in this current sensor 1A, compared with the current sensor 51 shown in FIG. 7, the magnetic characteristics of the core parts 52, 53 and the core parts 2, 3, 4 (the magnetic material used in the core part and the annular core) And the number of turns of the whole windings 54a and 54b and the number of turns of the whole windings 11a to 13c are the same (that is, detection of the alternating current I). Under the condition that the sensitivity is the same), the number of turns is smaller than that of the windings 54a and 54b (that is, the inductance value is smaller than the inductance value L1 of the windings 54a and 54b, and the capacitance of the parasitic capacitance of the windings 54a and 54b). Each of the windings 11a to 13c has a winding wound around the other core part (with the junction portion X having a large magnetic resistance interposed) between the windings 11a to 13c. Different core windings are wound portion are connected in series directly connected state) in.

  Therefore, the equivalent circuit of the windings 11a to 13c of the current sensor 1A is composed of a coil having an inductance value smaller than the inductance value L1 and a capacitor having a capacitance value smaller than the capacitance value C1 connected in parallel to the coil. The LC circuit is connected in series by the number of the windings 11a to 13c that are divided and wound into the cores 2, 3, and 4. For this reason, the upper limit frequency of the sensitivity frequency band for the current sensor 1A is higher than the upper limit frequency f1 of the frequency band for the sensitivity of the current sensor 51 in the same manner as the current sensor 1 (further, Can be higher than the upper limit frequency f2 of the current sensor 1). Thereby, according to this current sensor 1 </ b> A, it is possible to detect an alternating current I having a frequency higher than that of the current sensor 51 and further than that of the current sensor 1.

  In the current sensor 1A, the connection order of the windings in each of the series windings (11a, 12a, 13a), (11b, 12b, 13b), (11c, 12c, 13c) is changed. You can also. As an example, a series winding (11a, 12a, 13a) will be described as an example. Instead of the configuration in which the winding 11a, the winding 12a, and the winding 13a are connected in series, the winding 11a, the winding 13a, and A configuration in which the coils 12a are connected in series can be employed in any order such as the order of the windings 12a and the order of the windings 13a, 12a, and 11a.

  Next, the current sensor 1B will be described with reference to FIGS.

  The current sensor 1B includes an annular core RC formed by connecting four core portions 2, 3, 4, and 5 to each other, and a length of each core portion. In a state of being separated along the vertical direction, n windings (two in this example) are wound (two in each of the four core portions 2, 3, 4 and 5 in this example). 8 (= 4 × 2) wound windings 11a, 11b, 12a, 12b, 13a, 13b, 14a, 14b) are provided.

  Further, all the windings 11a to 14b are wound at the same pitch and the same number of turns using the same type of wire. In addition, all the windings 11a to 14b have the winding start end portion (see FIG. 5) on the same one side along the circumferential direction of the annular core RC in a state where the core portions 2, 3, 4, and 5 are configured as the annular core RC. 5 and 6 are wound so as to be end portions marked with ●. Further, all the windings 11a to 14b are in a state where the windings wound around the same core part are not directly connected to each other (in other words, a state where a winding wound around another core part is interposed) In) connected in series.

  Also in this current sensor 1B, although not shown, all the windings 11a to 14b are wound around the respective core portions 2, 3, 4 and 5 as in the current sensors 1 and 1A 2 ( = N) Among the windings, the jth windings (j is an integer of 1 to n) in series from the same side along the circumferential direction of the annular core RC are connected in series to form n series windings. A configuration in which the n series windings are connected in series as a whole, and are connected in series with a winding wound around another core part, that is, By connecting 2 (= n) series windings (11a, 12a, 13a, 14a) and (11b, 12b, 13b, 14b) in series in this order, all the windings 11a to 14b are connected to each other. A state in which windings wound around the core portion of the wire are interposed (windings 11a, 12a 13a, 14a, 11b, 12b, 13b, at 14b order) it is possible to adopt a configuration that is connected in series.

  Further, in the case where the number of the core portions 2, 3, 4, and 5 is an even number of 4 or more as in the current sensor 1B, as a result, in the same manner as in the above example, each method is described below. All the windings 11a to 14b wound around the cores 2, 3, 4 and 5 are connected in series with the windings wound around the other cores interposed. You can also.

  In this method, first, a plurality of core portions are referred to as a first half core portion (also referred to as a first half core portion group) and a second half core portion (also referred to as a second half core portion group) along the circumferential direction of the annular core RC. ), And then the windings included in the first half core portion group and the windings included in the second half core portion group from the same side along the circumferential direction of the annular core RC. By connecting the second windings in series, (n × number of core parts / 2) first serial windings formed by connecting two windings in series are formed.

  Specifically, in the current sensor 1B, as shown in FIG. 6, the first half side core part group (in this example, a group composed of core parts 2 and 3) and the second half side core part group (in this example, 11a, 11b, 12a, 12b included in the first half core group and 13a, 13b, 14a, 14b included in the second core group. The 1 (= j) -th windings 11a and 13a from the same one side along the circumferential direction of the annular core RC are connected in series to form one series winding, and the 2 (= j) -th winding The windings 11b and 13b are connected in series to form one series winding, and the 3 (= j) -th windings 12a and 14a are connected in series to form one series winding. (= J) The first windings 12b and 14b are connected in series to form one series winding.

  Next, with respect to the plurality of series windings described above, 2 (= n) pieces are connected in series so that one winding is wound around each of the core portions 2, 3, 4, and 5. Configure a series winding. Specifically, two series windings (11a, 13a, 12a, 14a) and (11b, 13b, 12b, 14b) are configured. Finally, these 2 (= n) series windings are connected in series. Thereby, all the coil | windings 11a-14b are connected in series in the state which interposed the coil | winding currently wound by the other core part. Specifically, the windings 11a, 13a, 12a, 14a, 11b, 13b, 12b, and 14b are connected in series. In addition, in FIG. 5, illustration of the line segment which shows the wiring which connects each coil | winding 11a-14b is abbreviate | omitted.

  Also in this current sensor 1B, compared with the current sensor 51 shown in FIG. 7, the magnetic characteristics of the core portions 52, 53 and the core portions 2, 3, 4, 5 (the magnetic material used in the core portion, and The length and the cross-sectional area when connected to the annular core are the same, and the number of turns of the windings 54a and 54b and the number of turns of the windings 11a to 14b are the same (that is, the alternating current I The number of turns is smaller than that of each of the windings 54a and 54b (that is, the inductance value is smaller than the inductance value L1 of each of the windings 54a and 54b, and the parasitic capacitance of each of the windings 54a and 54b). (The capacitance value of the parasitic capacitance is smaller than the capacitance value C1) of each of the windings 11a to 14b with the windings wound around the other core part interposed (junction part X having a large magnetic resistance) Sandwiched therebetween different core windings are wound portion are connected in series directly connected state).

  Therefore, an equivalent circuit of the entire windings 11a to 14b of the current sensor 1B includes a coil having an inductance value smaller than the inductance value L1 and a capacitor having a capacitance value smaller than the capacitance value C1 connected in parallel to the coil. The LC circuit is connected in series by the number of windings 11a to 14b that are divided and wound into the cores 2, 3, 4, and 5. For this reason, the upper limit frequency of the sensitivity frequency band for the current sensor 1B is set to a higher frequency than the upper limit frequency f1 of the frequency band for the sensitivity of the current sensor 51 in the same manner as the current sensor 1 described above. be able to. Thereby, according to this current sensor 1B, it is possible to detect an alternating current I having a higher frequency than the current sensor 51.

  Further, the plurality of windings 11a to 12c in each of the current sensors 1 are wound at the same pitch and the same number of turns by using the same type of wire so that the same equivalent circuit is obtained. Of course, as long as the same equivalent circuit is used, different types of wires may be used, the pitch may be changed, or the number of turns may be slightly changed.

  In addition, as an example of the measurement device including the current measurement device 21, the power measurement device 31 that measures the power value W <b> 1 of the power W, which is an example of the physical quantity of the measurement target conductor 61, has been described above, but the current measurement device 21 is provided. The measuring device can also measure physical quantities other than the electric power W for the measurement target conductor 61, for example, the impedance of the measurement target conductor 61. That is, an impedance measuring device including the current measuring device 21 can be realized with the same configuration as the power measuring device 31 described above.

  Further, the current sensors 1, 1A, 1B can be used as a single CT as in the above example, and can also be used as a zero flux type sensor. In this case, a magnetic sensor such as a Hall sensor is disposed at least one of the joint portions X of each core portion constituting the annular core RC, and a current that cancels the magnetic flux in the annular core RC based on the output of the magnetic sensor. And an amplifier that supplies the entire winding (feedback winding) wound around each core portion. Thus, the current sensors 1, 1A, 1B can detect the alternating current included in the low frequency band including the direct current in addition to the detection of the alternating current.

  In addition, by applying the current sensors 1, 1A, 1B capable of detecting direct current and alternating current to the current measuring device in this way, currents in currents in a wide frequency band from direct current to high frequency alternating current can be obtained. A current measuring device capable of accurately measuring the value can be realized. In addition, by using such a current measuring device for a power measuring device, an alternating current supplied to the measurement target conductor 61 based on a current value of a current in a wide frequency band from a direct current to a high frequency alternating current. It is possible to realize a power measuring device capable of accurately measuring not only power but also DC power. Similarly, a resistance measuring device that can measure not only the impedance of the conductor 61 to be measured but also the resistance value can be realized.

  Also, current sensors 1, 1A, 1B are incorporated, and using a detection current Id output from these current sensors 1, 1A, 1B, a tachometer that measures rotation, a phase difference meter that measures a phase difference, and Various measuring devices such as a frequency meter for measuring the frequency can be configured.

DESCRIPTION OF SYMBOLS 1 Current sensor 2, 3 Core part 11a, 11b, 11c, 12a, 12b, 12c Winding 61 Conductor to be measured CR Annular core

Claims (3)

A plurality of core portions connected to each other and configured in a ring shape, and an annular core into which a conductor to be measured is inserted, and a plurality of n portions (n is an integer of 2 or more) with a predetermined number of turns. With multiple windings wound around each of the
All the windings wound around the plurality of core parts are in a state in which the windings wound around the same core part interpose the windings wound around the other core part. Current sensor connected in series with. All the windings are j (j is 1 or more and n or less) from the same one side along the circumferential direction of the annular core among the n windings wound around each core part. An integer) th winding is connected in series to form n series windings,
The current sensor according to claim 1, wherein the n series windings are connected in series as a whole.   3. A measuring apparatus comprising the current sensor according to claim 1 or 2, wherein the current sensor outputs a detection current whose current value changes in accordance with a current value of an alternating current flowing through the conductor to be measured.

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