JP2013196861A - Ac inlet, current detection device, voltage detection device, electronic equipment, and power supply tap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AC inlet capable of saving a space and having a function for detecting a current.SOLUTION: A partition member 110 that is an insulation part is provided at the rear of a terminal holding part 103 holding a pair of input terminals 101a and 101b to which a current is inputted via a power cable. Current paths 106a and 106b connecting between the pair of input terminals 101a and 101b and a pair of output terminals 104a and 104b are arranged on an upper surface side of the partition member 110. A magnetism detection element 109 detecting a magnetic field generated from the current path 106a is arranged on a bottom surface side of the partition member 110.

Description

  The present invention relates to an AC inlet, a current detection device, a voltage detection device, an electronic device, and a power strip having a function of detecting current or power.

  In recent years, in order to suppress global warming, it has become essential to reduce CO2 emissions and improve the efficiency of power use. Therefore, it is important to monitor current or power in devices such as home appliances, OA equipment, and processing machines so as not to use wasted power. Ultimately, it is desirable to incorporate a monitoring device into each device (see Patent Document 1).

JP 2011-85796 A

  However, when a monitoring device is incorporated in each device as described above, it is necessary to separately prepare a space for mounting the monitoring device in each device. For this reason, the apparatus may have a large-scale configuration or may require a specification change or modification of the apparatus.

  Therefore, an object of the present invention is to provide an AC inlet having a function of detecting current, which can also save space.

  The present invention for achieving the above object is, for example, an AC inlet into which a power cable is inserted, a pair of input terminals for inputting a current through the power cable, and a terminal holding section for holding the pair of input terminals. A pair of output terminals for outputting the current input by the pair of input terminals, an insulating portion provided at an end of the terminal holding portion on the pair of output terminals side, and on one surface side of the insulating portion A current path that connects the pair of input terminals and the pair of output terminals, and a magnetic detection element that is provided on the other surface side of the insulating portion and detects a magnetic field generated from the current path. The AC inlet is characterized by comprising.

  The insulating portion has two surfaces formed along the insertion direction of the power cable, and the current path is provided on one surface side of the two surfaces, and the magnetic surface is disposed on the other surface side. A sensing element is preferably provided. Furthermore, it is preferable that the insulating portion protrudes from the end portion of the terminal holding portion toward the pair of output terminals and is provided integrally with the insulating portion. The current path and the magnetic sensing element are covered with a case, and the insulating portion functions as a partition that partitions the space inside the case into first and second spaces, and the current path is the first path. Preferably, the magnetic sensing element is disposed on the space side, and the magnetic sensing element is disposed on the second space side. Note that the case preferably includes a shield case.

  Further, the present invention is an AC inlet into which a power cable is inserted, and includes a pair of input terminals that input current through the power cable, a terminal holding portion that holds the pair of input terminals, and the pair of input terminals. A pair of output terminals for outputting the input current; a current path connecting the pair of input terminals and the pair of output terminals; a magnetic sensing element for detecting a magnetic field generated from the current path; and the current A case that covers a path and the magnetic sensing element, and a partition member that partitions the interior of the case into a plurality of rooms, and the current path is disposed on one surface side of the partition member inside the case, while the magnetic In the AC inlet, the detection element is arranged on the other surface side of the partition member inside the case.

  Furthermore, the present invention is an AC inlet into which a power cable is inserted, wherein a pair of input terminals for inputting a current from the outside through the power cable, a terminal holding part for holding the pair of input terminals, and the power cable A shield case disposed behind the terminal holding portion in the extraction direction, a pair of output terminals for outputting the current input by the pair of input terminals to the outside of the shield case, and the pair of input terminals; A current path that connects the pair of output terminals, a partition member that partitions the interior of the shield case into a plurality of rooms, and a second one that is different from the first room through which the current path passes among the plurality of rooms. The AC inlet is provided with a magnetic detection element that is provided in the room and detects a magnetic field generated from the current path.

  Here, in the present invention, the partition member is preferably an insulator and a nonmagnetic material. Moreover, it is preferable that the second room is mounted with a low-power component that operates by being supplied with a direct current. Furthermore, it is preferable that a leg member attached to the partition member in the second room and a circuit board supported by the leg member are further provided, and the magnetic sensing element is mounted on the circuit board. . Moreover, it is preferable that a conductor for connecting a ground input terminal surrounded by the terminal holding portion and a ground output terminal exposed to the outside of the shield case is provided in the second chamber.

  The present invention further includes a voltage detection circuit that detects a voltage applied to the pair of input terminals, and the voltage detection circuit has one end connected to a first input terminal of the pair of input terminals. It is preferable to include a first voltage dividing element and a second voltage dividing element having one end connected to a second input terminal of the pair of input terminals.

  Furthermore, in the present invention, the first voltage dividing element and the second voltage dividing element are provided in the first chamber, and the partition member includes the other end of the first voltage dividing element and the first voltage dividing element. A hole through which the other end of the second voltage dividing element is inserted is provided, and the other end of the first voltage dividing element is connected to one end of the third voltage dividing element in the second chamber. The other end of the second voltage dividing element is connected to one end of a fourth voltage dividing element in the second chamber, and the second chamber includes the first voltage dividing element and the third voltage dividing element. It is preferable that a differential amplifier circuit that differentially amplifies the voltage divided by the voltage element and the voltage divided by the second voltage divider element and the fourth voltage divider element is further provided.

  In addition, in this invention, it is preferable to further provide the electric power determination circuit which determines electric power from the electric current detected by the said magnetic detection element, and the voltage detected by the said voltage detection circuit. The magnetic sensing element is preferably a magnetic impedance element, a fluxgate sensor, or a giant magnetoresistive element.

  Furthermore, the present invention is an AC inlet into which a power cable is inserted, and includes a pair of input terminals for inputting a current from the outside through the power cable, a terminal holding unit for holding the pair of input terminals, and the power cable. A shield case disposed behind the terminal holding portion in the extraction direction, a pair of output terminals for outputting the current input by the pair of input terminals to the outside of the shield case, and the pair of input terminals; A current path that connects the pair of output terminals; a partition member that partitions the interior of the shield case into a plurality of rooms; and a voltage detection circuit that detects a voltage applied to the pair of input terminals. The detection circuit includes: a first voltage dividing element having one end connected to the first input terminal of the pair of input terminals; and a second input of the pair of input terminals. A second voltage dividing element having one end connected to a terminal, wherein the first voltage dividing element and the second voltage dividing element are arranged in a first room through which the current path passes among the plurality of rooms. The AC inlet is characterized by being provided.

  Here, in the present invention described above, the first voltage dividing element and the second voltage dividing element are provided in the first chamber, and the other end of the first voltage dividing element is provided in the partition member. And the other end of the second voltage dividing element is provided, and the other end of the first voltage dividing element is a third chamber in a second chamber different from the first chamber. The second voltage dividing element is connected to one end of the voltage dividing element, and the other end of the second voltage dividing element is connected to one end of the fourth voltage dividing element in the second chamber. A differential amplifier circuit that differentially amplifies the voltage divided by the first voltage dividing element and the third voltage dividing element and the voltage divided by the second voltage dividing element and the fourth voltage dividing element. Is preferably further provided.

  In the present invention, the current detection device is attached to an AC inlet into which a power cable is inserted, and the AC inlet includes a pair of input terminals for inputting current from the outside through the power cable and the pair of input terminals. A terminal holding part that holds the power supply cable, and the current detection device receives a shield case disposed behind the terminal holding part in a direction in which the power cable is pulled out, and the pair of input terminals inputs the shield case. A pair of output terminals for outputting current to the outside of the shield case, a current path connecting the pair of input terminals and the pair of output terminals, a partition member for partitioning the interior of the shield case into a plurality of rooms, Of the plurality of rooms, provided in a second room different from the first room through which the current path passes, In current sensing apparatus characterized by comprising a magnetic sensing element for detecting the magnetic field generated.

  Furthermore, in the present invention, the voltage detection device is attached to an AC inlet into which a power cable is inserted, and the AC inlet includes a pair of input terminals for inputting current from the outside through the power cable and the pair of input terminals. A shield case disposed behind the terminal holder in the direction in which the power cable is pulled out, and the current input by the pair of input terminals of the shield case. A pair of output terminals that output to the outside, a current path that connects the pair of input terminals and the pair of output terminals, a partition member that partitions the interior of the shield case into a plurality of rooms, and the pair of input terminals. A voltage detection circuit for detecting an applied voltage, wherein the voltage detection circuit is a first input of the pair of input terminals. A first voltage dividing element having one end connected to a terminal; and a second voltage dividing element having one end connected to a second input terminal of the pair of input terminals, the first voltage dividing element and the first The voltage-dividing element is provided in a first room through which the current path passes among the plurality of rooms.

  Further, the present invention can be applied to an electronic device having the above-described AC inlet, or can be applied to a power strip having at least one outlet for outputting a current supplied from the AC inlet. It is.

  ADVANTAGE OF THE INVENTION According to this invention, AC inlet provided with the function to detect an electric current which can also save space can be provided. Further, according to the AC inlet according to the present invention, a large-scale remodeling or the like of the electric device is unnecessary, and the assembly to the electric device or the like is easy. Furthermore, if a shield case is attached to the AC inlet, it is possible to provide a high-function AC inlet with a current detection function that can reduce the influence of a magnetic field and noise from the power supply unit and can also save space. .

It is an external appearance perspective view of an AC inlet. It is a sectional side view of an AC inlet. It is a plane sectional view of an AC inlet. It is a bottom sectional view of an AC inlet. It is a sectional side view of an AC inlet. It is a plane sectional view of an AC inlet. It is a bottom sectional view of an AC inlet. It is a circuit diagram which shows a voltage detection circuit. It is an external view which shows an example of an electronic device. It is a block diagram of an electronic device. It is a block diagram of a power strip. It is a block diagram of Example 1 which performs the current measurement with respect to a to-be-measured current. It is explanatory drawing of the mode of the electric current in a primary conductor, and a magnetic field. It is sectional drawing of the relationship between a primary conductor and a magnetic sensing element. It is a block diagram of a detection circuit. It is a distribution contour map of the magnetic field component of a Y-axis direction using the through-hole of 2 mm in diameter. It is a distribution contour map of the magnetic field component of a Y-axis direction using the through-hole of 3 mm in diameter. It is a related figure of the diameter of a through-hole, and the peak position of a Y-axis direction magnetic field component. It is a related figure of the diameter of a through-hole, and the peak value of a Y-axis direction magnetic field component. It is a block diagram of the modification which performs the current measurement with respect to a to-be-measured current. It is a block diagram of the modification which performs the current measurement with respect to a to-be-measured current. It is a block diagram of the modification which performs the current measurement with respect to a to-be-measured current. It is a block diagram of the modification which performs the current measurement with respect to a to-be-measured current. It is a block diagram of Example 2 which performs the current measurement with respect to a to-be-measured current. It is a characteristic view of a magneto-impedance element. It is a graph figure of a detection electric current and a measurement error. It is a block diagram of the modification which performs the current measurement with respect to a to-be-measured current. It is a perspective view of the basic composition of the current sensor of Example 3 which performs the current measurement to the current to be measured. It is explanatory drawing of the mode of a magnetic field with the electric current in a primary conductor. It is sectional drawing of the relationship between a primary conductor and a magnetic sensing element. It is a block diagram of a detection circuit. It is a block diagram of the modification which performs the current measurement with respect to a to-be-measured current. It is a block diagram of Example 4 which performs the current measurement with respect to a to-be-measured current. It is a block diagram of the modification which performs the current measurement with respect to a to-be-measured current. It is a block diagram of the other modification which performs the current measurement with respect to a to-be-measured current. It is a block diagram of Example 5 which performs the current measurement with respect to a to-be-measured current. It is a block diagram of the modification which performs the current measurement with respect to a to-be-measured current. It is a perspective view of the basic composition of the current sensor of Example 6. It is explanatory drawing of the mode of a magnetic field with the electric current in a primary conductor. It is sectional drawing of the relationship between a primary conductor and a magnetic sensing element. It is a distribution contour map of the magnetic field component of the Y-axis direction in which the width of the current inlet / outlet is changed. It is a distribution contour map of the magnetic field component of the Y-axis direction in which the width of the current inlet / outlet is changed. It is a distribution contour map of the magnetic field component of the Y-axis direction in which the width of the current inlet / outlet is changed. It is a distribution contour map of the magnetic field component of the Y-axis direction in which the width of the current inlet / outlet is changed. FIG. 6 is a relationship diagram between the width of the current inlet / outlet and the peak value of the magnetic field component in the Y-axis direction. It is a block diagram of the modification which performs the current measurement with respect to a to-be-measured current. It is a block diagram of the modification which performs the current measurement with respect to a to-be-measured current. It is a block diagram of the modification which performs the current measurement with respect to a to-be-measured current. It is a block diagram of Example 7 which performs the current measurement with respect to a to-be-measured current. FIG. 5 is a relationship diagram between a current entrance / exit position and a magnetic field component (fixed point) in the Y-axis direction. It is a block diagram of Example 8 which performs the current measurement with respect to a to-be-measured current. It is a graph of the relationship between the measured current and the output when the width of the entrance / exit is changed.

  The present invention will be described in detail based on the embodiments shown in the drawings.

<Example A>
The AC inlet according to the embodiment will be described with reference to FIGS. 1 to 4 are a perspective view, a side sectional view, a plan sectional view, and a bottom sectional view showing the appearance of the AC inlet 140, respectively.

  In FIG. 1, an AC inlet 140 into which a power cable is inserted has a pair of input terminals 101a and 101b for inputting a current from the outside through the power cable, a ground input terminal 102, an insulating member 103, and a power source cable in the direction of pulling out. A shield case 116 disposed behind the insulating member 103 is provided. The shield case 116 is provided with a connector connection window 141. A cable for outputting a detection result of current, voltage or power through the window 141 is connected to the connector 142. The insulating member 103 is a terminal holding portion that holds the first input terminal 101 a, the second input terminal 101 b, and the ground input terminal 102. In the embodiment, the insulating member 103 is a surrounding cylindrical insulating member.

  In FIG. 2, on the front side of the AC inlet 140, a pair of input terminals 101a and 101b for receiving power from the outside of the electronic device and a ground input terminal 102 are provided. The insulating member 103 is formed of, for example, an insulating resin member, and constitutes a socket portion (receptacle portion) into which a plug of the power cable is inserted and removed. The dimensions and the like of the input terminals 101a and 101b, the ground input terminal 102, and the insulating member 103 are defined in, for example, the international standard IEC60320-1 standard sheet C14. Of course, conforming to this standard is not essential to the present invention.

  On the rear side of the AC inlet 140, a pair of output terminals 104a and 104b for outputting the current input from the pair of input terminals 101a and 101b to the outside of the shield case 116 are provided. The current output from the pair of output terminals 104a and 104b is supplied to a power supply unit of an electronic apparatus such as an image forming apparatus or an image reading apparatus. Note that the AC inlet 140 may be directly mounted on the power supply unit or may be mounted on a casing of the electronic device.

  As shown in FIG. 2, the AC inlet 140 is provided with a partition member 110 that partitions the inside of the shield case 116 into a plurality of rooms. The partition member 110 is, for example, an insulator and a nonmagnetic material, and is a member that insulates the AC side (primary side) and the DC side (secondary side). As shown in FIG. 2, if the partition member 110 is parallel to the surface formed by the bottom end portions of the pair of input terminals 101 a and 101 b, the space efficiency inside the shield case 116 is good.

  The inside of the shield case 116 is partitioned into a first space (first room 107) and a second space (second room 111) by the partition member 110. In the first room 107, a pair of current paths 106a and 106b for connecting the pair of input terminals 101a and 101b and the pair of output terminals 104a and 104b are arranged. The pair of input terminals 101a and 101b and the pair of output terminals 104a and 104b are members integrally formed of, for example, copper or a copper alloy. The input terminals 101a and 101b and the current paths 106a and 106b are electrically connected by solder 108, for example. The input terminals 101a and 101b and the current paths 106a and 106b may be processed into a shape that fits to each other. Alternatively, the input terminals 101a and 101b and the current paths 106a and 106b may be soldered with the solder 108 after being fitted to each other. As shown in FIG. 3, the current paths 106 a and 106 b are fixed to the upper surface side of the partition member 110 by an adhesive 114.

  In the second chamber 111 determined by the partition member 110, low-power components that operate by being supplied with a direct current, such as the magnetic sensing element 109 and the microprocessor 143 that calculates current, voltage, power, and the like, are mounted. . In addition, a conductor 115 is provided in the second chamber 111. The conductor 115 is a conductor that connects the ground input terminal 102 surrounded by the cylindrical insulating member 103 and the ground output terminal 105 exposed to the outside of the shield case 116. The conductor 115 is electrically connected to the shield case 116. As a result, the shield case 116 easily functions as a shield that protects internal circuits from electromagnetic noise and magnetic fields.

  The magnetic detection element 109 is mounted on the circuit board 112 and detects a current flowing through the current path 106a by detecting a magnetic field generated from the current path 106a. In order to operate the magnetic detection element 109, a separate DC power source is required. Since the magnetic detection element 109 directly detects the magnetic field from the current path 106a, a highly sensitive magnetic sensor capable of detecting a micro Tesla order magnetic field may be employed. For example, a magnetic impedance element, a fluxgate sensor, or a giant magnetoresistive element as shown in Patent Document 1 or Patent Document 2 may be employed.

  As shown in FIG. 4, the magnetic field detection direction of the magnetic detection element 109 is the direction of the arrow m. The magnetic detection element 109 is mounted on the circuit board 112 so as to face the current path 106a with the partition member 110 interposed therebetween.

  The magnetic field generated from the current path 106 a depends on the amount of current flowing through the current path 106 a and the distance between the magnetic sensing element 109. Therefore, the above distance is determined so that the magnetic field range suitable for the magnetic detection element 109 is obtained. In addition, currents flow in opposite directions in the current paths 106a and 106b. Therefore, the position where the magnetic detection element 109 is placed is set in consideration of each influence.

  In order to maintain the dimensional relationship of the magnetic detection element 109, the current paths 106 a and 106 b are fixed to the partition member 110. Further, the circuit board 112 is supported by a height restricting convex portion 113 that is a leg member attached to the partition member 110. As a result, the magnetic sensing element 109 is limited in variation in distance with respect to the current paths 106a and 106b, so that a current sensor with little variation can be realized.

  In Example A, the current paths 106a and 106b are fixed to the partition member 110 with the adhesive 114, but may be press-fitted into a resin material used for the partition member 110 or may be insert-molded integrally.

  In Example A, the magnetic detection element 109 is mounted on the circuit board 112. However, the magnetic detection element 109 with the terminal protruding may be directly bonded to the partition member 110 without using the circuit board 112.

  Input / output of the circuit board 112 is performed via the connector 142. The front side of the AC inlet 140 is occupied by the input terminals 101a and 101b, and the rear side is occupied by the output terminals 104a and 104b. Further, a window portion 141 for the connector 142 may be provided on the other side surface (upper surface, bottom surface, left side surface or right side surface) in order to take a distance for insulation.

  When using the high-sensitivity magnetic sensing element 109, the shield case 116 is placed on the other surface except the front surface of the AC inlet 140. The shield case 116 of Example A is deep drawn with an iron-based material. However, the shield case 116 may be formed in a box shape with a thin plate having a high magnetic permeability such as permalloy.

  By the way, the AC inlet 140 includes a receptacle and a current detection device. The receptacle includes a pair of input terminals 101a and 101b, a ground input terminal 102, and an insulating member 103. Receptacles are standardized and are available on the market from multiple manufacturers. Therefore, only the current detection device portion of the AC inlet 140 described in the embodiment A may be implemented. In this case, the AC inlet 140 can be completed by purchasing and selecting a portion of the receptacle freely and connecting the current detection device to the receptacle as a retrofit.

  As described above, according to this embodiment, the current paths 106 a and 106 b are arranged on one side of the partition member 110 that is an insulating portion, and the magnetic detection element 109 is arranged on the other side of the partition member 110. That is, the magnetic detection element 109 can be protected from the alternating current flowing through the current paths 106 a and 106 b by the partition member 110. In addition, the one surface and the other surface of the partition member 110 correspond to two surfaces (an AC side surface and a DC side surface) formed in the partition member 110 along the insertion direction of the power cable. Further, since the magnetic detection element 109 can be protected from alternating current, the AC inlet can be reduced in size. The partition member 110 may be attached to the end of the insulating member 103 on the output terminal side, or the partition member 110 may be configured integrally with the insulating member 103. In the latter case, the partition member 110 will be molded so as to protrude from the insulating member 103 to the output terminal side.

  Since an electronic device includes a power supply unit, it is convenient if current and power can be detected by the power supply unit. However, the power supply circuit board needs to have a sufficient creepage distance for insulation. For this reason, low-power sensors and microcomputers cannot be mounted with high density, and space is required. In addition, the current sensor may not operate correctly due to the influence of the magnetic field leaking from the transformer of the power supply unit. Furthermore, there is a possibility that a microcomputer that performs power calculation may malfunction due to noise from the power supply unit. That is, various restrictions may be imposed on incorporating a current or power detection circuit on the power circuit board. Therefore, if the AC inlet and the detection circuit can be integrated with each other in an AC inlet provided on the outer peripheral portion of the apparatus for connecting a power supply section in the apparatus and a cable connected to a power outlet such as a commercial AC power supply, the AC inlet and the detection circuit can be saved. I found that it leads to space.

  That is, according to the present embodiment, the AC inlet 140 is provided in which the magnetic detection element 109 that detects current is mounted in the shield case 116 provided behind the cylindrical insulating member 103. In particular, the shield case 116 reduces the influence of a magnetic field and noise from the power supply unit included in the electronic device. Further, the inside of the shield case 116 is partitioned into a plurality of rooms by a partition member 110. A pair of current paths 106a and 106b pass through the first room 107. A magnetic detection element 109 is provided in the second room 111. As described above, since the magnetic detection element 109 for detecting current is arranged in the second room 111, space saving of the AC inlet 140 is realized.

  By forming the partition member 110 with an insulator and a non-magnetic material, a sufficient insulation distance can be secured between the primary side and the secondary side. In particular, in the second room 111, the weak electric parts that are operated by being supplied with a direct current are collectively mounted, so that the weak electric parts can be protected from the alternating current.

  Further, a leg member is attached to the partition member 110 in the second chamber 111, thereby supporting the circuit board 112, and the magnetic detection element 109 is provided on the circuit board 112. Thereby, the magnetic detection element 109 can be accurately positioned with respect to the current path 106a which is a current measurement target. This will also increase the current measurement accuracy. The ground conductor 115 passes through the second chamber 111. This means that the partition member 110 is disposed in a small space between the current paths 106a and 106b and the grounding conductor 115. Such an arrangement is useful for miniaturizing the AC inlet 140 having at least a current detection function. In addition, although the present Example demonstrated the structure which divided | segmented the inside of the shield case 116 with the partition member 110 and formed the primary side room and the secondary side space, this invention is not limited to this. Absent. For example, a configuration may be adopted in which an insulating portion is provided so as to protrude from an end portion (specifically, a central portion of the end surface) of an insulating member (terminal holding portion) that holds a pair of input terminals without providing a shield case. In this case, a current path is provided on one surface of the insulating portion (one surface along the insertion direction of the power cable), and magnetic detection is performed on the other surface of the insulating portion (the other surface along the insertion direction of the power cable). An element may be provided. With such a structure, further space saving can be realized. In addition, it is preferable that the above-described insulating portion protrude from the end portion of the terminal holding portion toward the pair of output terminals and be provided integrally. Further, in the above-described embodiment, the structure covered with the shield case 116 is illustrated. However, a structure covered with a case having no shielding function may be used. Or it is good also as a structure which covers functional parts, such as a current path and a magnetic detection element, by a part of terminal holding part by extending the edge part edge of the terminal holding part mentioned above in the cylinder shape to the output terminal side.

<Example B>
In Example B, an embodiment in which a voltage detection circuit is further provided to enable power detection will be described. In evaluating power, it is possible to roughly evaluate only by current measurement, but the power depends on the load. Therefore, the power cannot be accurately evaluated only with the current. Therefore, if the current and voltage are detected, the power can be obtained more accurately. In the following description, the same parts as those in the embodiment A are given the same reference numbers to simplify the description.

  By the way, a plug of a power cable from an external power source such as a commercial AC power source is connected to a pair of input terminals 101a and 101b. Therefore, in Example B, if the voltages of the input terminals 101a and 101b are evaluated and the difference between them is taken, an accurate detection voltage can be obtained regardless of the polarity connection.

  5 is a side sectional view of the AC inlet 140, FIG. 6 is a top sectional view of the AC inlet 140, and FIG. 7 is a bottom sectional view of the AC inlet 140. FIG. 8 is a diagram illustrating a voltage detection circuit that detects a voltage by a capacitive voltage division method.

  As shown in FIGS. 5 and 6, the capacitor C1a is a first voltage dividing element having one end connected to the current path 106a. The capacitor C1b is a second voltage dividing element having one end connected to the current path 106b. Capacitors C1a and C1b each have a low capacitance (for example, 15 pF). Capacitors C <b> 1 a and C <b> 1 b are provided in the first room 107. The reason why the capacitors C1a and C1b connected to the current paths 106a and 106b are arranged in the first chamber 107 is that it is advantageous from the viewpoint of insulation. As the capacitors C1a and C1b, leaded capacitors are suitable from the viewpoint of routing the terminals. Further, as the capacitors C1a and C1b, it is necessary to use capacitors having a high withstand voltage from the viewpoint of surge resistance. For this reason, the sizes of the capacitors C1a and C1b tend to be large. However, the capacitors C1a and C1b can be accommodated in the first room 107 by being placed side by side.

  On the other hand, as shown in FIG. 7, in the second chamber 111, the capacitor C <b> 2 a that is the third voltage dividing element and the capacitor C <b> 2 b that is the fourth voltage dividing element are mounted on the circuit board 112. Capacitors C2a and C2b are large-capacity (eg, 15000 pF) capacitors. One ends of the capacitors C2a and C2b are connected to the other ends of the capacitors C1a and C1b, respectively. The other ends of the capacitors C2a and C2b are each connected to ground.

  The other end of the two terminals of the capacitors C1a and C1b that is not connected to the current paths 106a and 106b is inserted into the through-hole portion 25 provided in the partition member 110 and connected to the circuit of the second chamber 111. . In addition, when the creepage distance of the other end of the capacitors C1a and C1b with respect to the current paths 106a and 106b is insufficient, an enclosing wall 26 may be provided as shown in FIG. The surrounding wall 26 is also formed of an insulating member. The surrounding wall 26 may be formed integrally with the partition member 110.

  As shown in FIG. 8, the capacitors C1a and C2a form a first voltage dividing circuit, and the capacitors C1b and C2b form a second voltage dividing circuit. The voltages at these voltage dividing points are Va and Vb. For example, when AC 100V is applied to the current paths 106a and 106b, voltages corresponding to the impedance ratio appear in the voltage Va and Vb at the voltage dividing point. If the impedance ratio is 1000: 1, a voltage of ± 0.28 Vpp appears.

  An impedance conversion circuit 123 such as a bootstrap circuit is provided after the voltage dividing circuit. Further, a differential amplifier circuit 124 is provided at the subsequent stage of the impedance conversion circuit 123. The differential amplifier circuit 124 differentially amplifies the voltage divided by the first voltage dividing element and the third voltage dividing element and the voltage divided by the second voltage dividing element and the fourth voltage dividing element. It is a differential amplifier circuit. An impedance conversion circuit 123 and a differential amplifier circuit 124 are also provided in the second chamber 111. As a result, SVout is obtained as the output of the voltage detection circuit. SVout is input to the A / D port of the microprocessor 143. The detection result from the magnetic detection element 109 is input to another A / D port provided in the microprocessor 143. The microprocessor 143 calculates power from the detected current and voltage, and outputs the power to the display device or an external computer through the connector 142. As described above, the microprocessor 143 functions as a power determination circuit that determines power from the current detected by the magnetic detection element 109 and the voltage detected by the voltage detection circuit.

  There is a slight variation in the capacitance of the capacitor, and the difference in sensitivity between Va and Vb may be a concern. In this case, the sensitivity balance may be finely adjusted by inserting an attenuator between the impedance conversion circuit 123 and the differential amplifier circuit 124. Further, when the voltage detection circuit shown in FIG. 8 is operated by a single power source, the ground shown in FIG. 8 may be set to the sensor GND (middle point potential).

  In the example B, the voltage detection is performed by the capacitor. However, a resistor voltage dividing circuit may be employed by replacing the capacitor with a resistor.

  By the way, the AC inlet 140 of the embodiment B includes a receptacle, a current detection device, and a voltage detection device. If only voltage sensing is required, the current sensing device may be omitted from the AC inlet 140. That is, the AC inlet 140 in which only the voltage detection device is incorporated may be provided. Further, as described in the embodiment A, the current detection device and the voltage detection device in the embodiment B excluding the receptacle may be provided as the power detection device. In this case, the AC inlet 140 can be completed by freely selecting and purchasing a portion of the receptacle and connecting the voltage detection device or the power detection device to the receptacle later.

  According to the present invention, an AC inlet 140 having a voltage detection function can be provided by providing the AC inlet 140 with a voltage detection circuit that detects a voltage applied to the pair of input terminals 101a and 101b. Furthermore, if it is mounted together with the above-described current detection circuit, the power can be measured more accurately from the voltage and current detection results.

  In particular, in the voltage detection circuit, the capacitor C1a as the first voltage dividing element and the capacitor C1b as the second voltage dividing element are arranged in the first chamber 107. On the other hand, the capacitor C2a as the third voltage dividing element and the capacitor C1b as the fourth voltage dividing element are arranged in the second chamber 111. These voltage dividing elements must be connected to form a voltage dividing circuit. Therefore, the partition member 110 is provided with a hole through which the other end of the first capacitor element and the other end of the second capacitor element are inserted. Thereby, it becomes easy to measure the voltage while securing the insulation distance. In addition, space-saving is achieved by distributing the voltage dividing elements in a plurality of rooms.

<Example C>
In the embodiment C, an application example of the AC inlet 140 described in the embodiments A and B will be described. The receptacle portion of the AC inlet 140 is widely spread as defined by international standards. Therefore, for electronic devices and electronic taps supplied to many countries, a conversion cord (power cable) suitable for the power plug in that country may be bundled and sold. Thereby, the main body of an electronic device or an electronic tap can be shared. In particular, if the AC inlet 140 of Examples A and B is used in such an electronic device or electronic tap, power can be easily monitored and controlled regardless of the power supply circuit.

  For example, in the image forming apparatus 27 as shown in FIG. 9, the AC inlet 140 is provided on the outer periphery thereof. The block diagram is shown in FIG.

  There are various types of external power outlets. There are power outlets 128a and 128b. Therefore, the conversion cord 129 is a plug whose one end matches the power outlet of each country and whose other end matches the receptacle of the AC inlet 140. A power supply circuit 130 is connected to the pair of output terminals 104 a and 104 b and the ground output terminal 105 of the AC inlet 140. The power supply circuit 130 converts the input alternating current and generates a plurality of direct currents required by the electronic device.

  In the AC inlet 140, the microprocessor 143 obtains AC current, voltage, power, and the like, and outputs the obtained value to the control circuit 131 via an interface such as UART or SPI. The control circuit 131 grasps the power amount of the entire electronic device and controls the drive unit 132 so as not to exceed the preset upper limit. Alternatively, the control circuit 131 may send display data indicating the amount of power to the display unit 133 to visualize the amount of power used. Further, the power data may be distributed to an external computer or the like by the LAN connector 134. As a result, the amount of power can be managed from the network.

  By easily detecting the current, voltage, or power with the AC inlet 140 having such a popular receptacle, it is possible to easily grasp the power supply state with almost no burden on the hardware design of the electronic device body. Is possible.

  As shown in FIG. 11, the AC inlet 140 may be incorporated in the power strip 135. The power tap 135 includes at least one outlet 136 that outputs the current supplied from the AC inlet 140. Current, voltage, or power data may be monitored by an external computer via a USB or LAN line from the connector 142 of the AC inlet 140 of the power strip 135. Data transfer may be wired or wireless.

  As described above, according to the present invention, an electronic device including the AC inlet 140 and the power strip 135 can be provided. Since the AC inlet 140 has a detection function for detecting current, voltage, and power, there is an advantage that a detection function can be easily added to an electronic device or the like. Further, since the AC inlet 140 has a very compact configuration, it is easy to ensure the degree of freedom of space on the electronic device side.

  By the way, in order to incorporate the above-described current detection circuit into the AC inlet 140, the current detection circuit must be miniaturized so that the current detection circuit is sufficiently accommodated in the second room 111 in the shield case 116. Further, in order to incorporate a current detection circuit and the like together with the noise filter in the shield case 116, the space restriction becomes more severe. An example of the current detection circuit is a circuit using a current transformer. However, in order not to saturate the magnetic core, the current transformer needs to have a certain size. Therefore, a current detection circuit using a current transformer is not suitable for use in the AC inlet 140. Moreover, since the current detection circuit using a Hall element also requires a magnetic collecting core, the core cannot be made small from the viewpoint of magnetic saturation. If a shunt resistor is inserted into the AC line, size problems are unlikely to occur. However, since insulation is necessary for a signal to be extracted, a photocoupler or the like is essential. Therefore, there is a problem with compactness. In addition, since the shunt resistor generates a large amount of heat when there is a large amount of current, it can only handle a current of about several A. Therefore, the present invention provides a magnetic detection element that detects a current by directly detecting a magnetic field from a current path.

  Hereinafter, the current path 106a is referred to as a primary conductor.

<Example 1>
FIG. 12 is a basic configuration diagram of the first embodiment for measuring current with respect to the current to be measured. A current to be measured I to be detected flows through the primary conductor 1, and the primary conductor 1 is in the form of, for example, a bus bar formed of a copper foil pattern or a copper plate on a printed board.

  A circular through hole 2 which is a non-conductive region is provided in the approximate center of the primary conductor 1 in order to partially block the current. For this reason, a part of the current I to be measured is shown in FIG. Thus, the detour current Ia slews symmetrically around the outside on both sides of the through-hole 2. For convenience of explanation, a coordinate axis is set for the primary conductor 1, the center of the through hole 2 is set as the origin O, the main direction in which the current I to be measured flows is the Y axis, the width direction that is the orthogonal axis is the X axis, and the thickness The direction is the Z axis.

  On the primary conductor 1, a magnetic detection element 3 having magnetic field detection sensitivity only in one direction is disposed. The detection unit 4 of the magnetic detection element 3 is set so that the Y-axis direction is the magnetic field detection direction, and the center position of the detection unit 4 is a distance dx in the X-axis direction and the X-axis in the Y-axis direction from the center of the through hole 2. Is placed at a location shifted by a distance dy across the surface.

  Originally, the magnetic flux generated by the current is directed in a direction perpendicular to the current direction, so that the current to be measured I flows in the Y-axis direction, which is the main direction, in a place where the through hole 2 of the primary conductor 1 is not affected. Therefore, like the magnetic field vector component Hc0 shown in FIG. 13, the magnetic field has only the vector component Hx in the X-axis direction within the width w of the primary conductor 1.

  However, in the vicinity of the through hole 2, the bypass current Ia is inclined with respect to the Y-axis direction, so that a magnetic field vector component Hc 1 in which the magnetic field is distorted on both sides of the through hole 2 is generated by this bypass current Ia. That is, the Y-axis direction vector component Hy and the X-axis direction vector component Hx are generated in the slope portion of the bypass current Ia. The vector sum of the vector component Hy and the vector component Hx is proportional to the magnitude of the current I to be measured, and since the current direction is symmetrical on both the positive and negative sides of the Y-axis of the through-hole 2, the vector component Hy is symmetrical across the X-axis. And the polarity is reversed.

  As shown in FIG. 12, even if the primary conductors 1 ′ through which currents of different phases flow are close to each other and the direction of the proximity current I ′ is parallel to the current I to be measured, the magnetic field vector component due to the proximity current I ′ is X It is a component only in the axial direction and has no Y-axis direction component. When the magnetic field detection direction of the detection unit 4 is the Y-axis direction, the magnetic detection element 3 can detect only the vector component Hy of the detour current Ia without being affected by the magnetic field due to the proximity current I ′. Therefore, if the vector component Hy is calibrated and converted, the amount of current I to be measured can be obtained.

  It is not desirable to detect the magnetic field vector component Hx in the X-axis direction as the magnetic sensing element 3 to be used. Therefore, a magnetic impedance element or an orthogonal flux gate element with high directivity is suitable. In the first embodiment, a magnetic impedance element is used, and a magnetic field can be detected only in the Y-axis direction. The magnetic thin film pattern is arranged in parallel in the Y-axis direction of the magnetic field detection direction as the detection unit 4, and a high frequency pulse in the MHz band is applied to the electrodes 5 at both ends, and the voltage amplitude change from both ends of the detection unit 4 due to the change in the magnetic field Is obtained as a sensor signal. Although not shown in the drawings, the operation of the detection unit 4 requires a bias magnetic field, and is set by passing a current by installing a bias magnet nearby or winding a bias coil as necessary.

  As shown in FIG. 14, the height h of the detection unit 4 of the magnetic detection element 3 with respect to the primary conductor 1 is a structure that holds the positional relationship between the primary conductor 1 and the magnetic detection element 3. It is determined by the relationship of dielectric strength such as distance.

  FIG. 15 shows a configuration diagram of a detection circuit 100A that functions as a current measuring device. The detection unit 4 of the magnetic detection element 3 is connected to a resistor R that forms a bridge with respect to the CR pulse oscillation circuit 30. The detection circuit 31 extracts an amplitude change from the both-end voltage that is a detection signal of the detection unit 4 and outputs the change to the amplification circuit 32. The amplifier circuit 32 amplifies the amplitude change and outputs it. The estimation circuit 33 is a circuit that estimates the amount of current to be measured from the output of the amplifier circuit 32.

  16 and 17 show the simulation results of the magnetic field component Hy in the Y-axis direction related to the bypass current Ia through the through hole 2. The primary conductor 1 is a sufficiently long copper plate having a cross section with a width w = 10 mm in the X-axis direction and a thickness t = 70 μm in the Z-axis direction and an infinite length in the Y-axis direction. A through hole 2 is formed. The detector 4 was fixed at a height h of 1.6 mm from the primary conductor 1 and examined the change of the magnetic field vector component Hy in the Y-axis direction when the measured current I flowed 1 ampere (A) in the Y-axis direction. .

  16 shows the calculation result of the magnetic field distribution of the vector component Hy of the magnetic field in the Y-axis direction when the through hole is 2 mm, and FIG. 17 shows the distribution of contour lines. The coordinates are the first quadrant of X ≧ 0 and Y ≧ 0, and the contours are drawn in 10% increments with the vertex of the vector component Hy being 100%. In the other quadrants, a magnetic field distribution symmetric with respect to the X axis or the Y axis is formed, the third quadrant has the same polarity as the first quadrant, and the second and fourth quadrants have a magnetic field having the opposite polarity to the first quadrant.

  16 and 17, the peak position where the magnetic field is maximized is in the direction of about 45 degrees from the through hole 2. In the through hole 2 having a diameter of 2 mm, (X, Y) = (1.5 mm, 1.625 mm), 3 mm. In the through hole 2, (X, Y) = (1.75 mm, 1.75 mm). The magnetic field components Hy at the peak positions of these magnetic fields are Hy = 25.6 m Gauss (G) and Hy = 47.9 m Gauss (G), respectively, for a current of 1 ampere (A).

  FIG. 18 is a graph showing the relationship between the diameter of the through hole 2 and the peak position of the magnetic field vector component Hy in the Y-axis direction. Although not shown in the contour diagrams shown in FIGS. 16 and 17, the results for diameters of 1 mm and 4 mm are also shown. As can be seen from FIG. 18, the diameter of the through hole 2 hardly depends on the position of the peak portion. Considering the result of the diameter 1 mm of the through hole 2 at the width w = 5 mm, the peak range of the vector component Hy is about 1-2 mm in both the X and Y axis directions in the practical use range of the primary conductor 1. It can be said that.

  Further, since 90% of the range 10% lower than the peak position is a circle having a radius of about 0.5 mm, the distances dx and dy in FIG. 1 are both 0.5 to 2.5 mm in terms of design. It is only necessary that the detection unit 4 of the magnetic detection element 3 is applied to this range.

  FIG. 19 is a graph of the diameter of the through hole 2 of the primary conductor 1 and the peak value of the vector component Hy in the Y-axis direction. As the diameter increases, the vector component Hy increases as a quadratic function. I understand that. That is, several times measurement is possible by simply fixing the detection unit 4 of the magnetic detection element 3 and changing the size of the diameter of the through hole 2 around the distances dx = 1.5 mm and dy = 1.5 mm shown in FIG. The range can be selected.

  In FIG. 12, the magnetic detection element 3 is provided in the first quadrant on the XY plane, but it can also be arranged in other quadrants due to symmetry.

  FIG. 20 shows a modification, in which a through hole 2 ′ is provided at a 45 degree direction from the origin O where the through hole 2 is located with respect to the X-axis direction, and the magnetic sensing element 3 is disposed at an intermediate position between them. The effect of the detour current Ia by the holes 2 and 2 ′ is overlapped, and the magnetic field of the Y-axis direction component is increased to increase the sensitivity. The two through holes 2, 2 'do not have to be the same size, and the number of the through holes 2 can be further increased, and the installed angular position may be designed according to the current detection specifications.

  As a means for bypassing the current, not only the through-hole 2 but also a notch hole is used to form a non-conductive region, which can correspond to a large or small current. For example, as shown in FIG. 21, a bypass current can be generated by providing a notch hole 8 at the end of the primary conductor 1 in the width direction. This configuration is suitable when it is desired to suppress a magnetic field caused by a bypass current due to a large current.

  On the contrary, as shown in FIG. 22, it is possible to deepen the notch hole 8, concentrate the detour current, increase the magnetic field of the Y-axis direction component, and cope with a small current. Furthermore, as shown in FIG. 23, by providing the notch hole 8 so as to be shifted from the opposite end, it is possible to further increase the detour current and cope with a smaller current.

<Example 2>
FIG. 24 is a configuration diagram of the second embodiment. For example, the primary conductor 12 made of a copper pattern having a width of 10 mm in the X-axis direction, a thickness of 70 μm in the Z-axis direction, and a length of 50 mm in the Y-axis direction is provided on one side of the sensor substrate 11 made of glass epoxy material having a thickness of 1.6 mm. Is provided. A through hole 13 having a diameter of 2 mm, for example, is formed by etching in the center of the primary conductor 12 in the X-axis direction. On the other surface of the sensor substrate 11, an integrated magnetic detection unit 14 is disposed at the same position as in FIG. 25, and electrodes 15 a to 15 b for soldering are drawn out on the sensor substrate 11.

  A magnetic impedance element is used for the magnetic detection unit 14, and the detection unit 16 made of an Fe—Ta—C magnetic thin film has, for example, eleven elongated pieces each having a width of 18 μm, a thickness of 2.65 μm, and a length of 1.2 mm. Patterns are arranged in parallel. The magnetic field detection direction of the detection unit 16 is only the Y-axis direction.

  The position of the detection unit 16 is offset from the center of the through-hole 13 in the X-axis and Y-axis directions by a distance dx = 1.5 mm and dy = 1.5 mm. Although not shown, the plurality of magnetic thin film patterns of the detector 16 are electrically folded in series and connected in series, and both ends are connected to respective electrodes, and soldered to the electrodes 15a and 15b on the sensor substrate 11. Bonded and connected to a sensor circuit (not shown). In FIG. 24, a high frequency pulse is applied by the flow of the electrodes 15a → 15b.

  The magnetic thin film of the magnetic detection unit 14 is provided with an easy magnetization axis in the width direction in the X-axis direction. When a high-frequency pulse is applied to the pattern of the magnetic thin film, the impedance is changed by an external magnetic field, and the magnetic detection unit 14 is converted into a sensor signal by amplitude detection.

  In the evaluation of the influence of currents other than the current I to be measured flowing in parallel, as shown in FIG. 24, a copper rod 18 having a diameter of 2 mm is arranged in parallel at an interval of 10 mm from the primary conductor 12 and a current of 10 Arms at 50 Hz. Measurement was performed under the condition that I ′ was passed and no current was passed through the primary conductor 12. Then, in the magnetic detection unit 14, the influence of the current I ′ flowing through the copper rod 18 was not observed, and it was below the noise level (10 mVpp or below).

  The magnetic field from the adjacent parallel current line is in the X-axis or Z-axis direction, and it has an effective effect that it has no component in the Y-axis direction and that the magneto-impedance element has no sensitivity in the X-axis direction, It was confirmed that the influence of the magnetic field due to the adjacent current is at a level that does not cause a problem.

  In the 5 V pulse drive of 5 V, the magnetic detection unit 14 exhibits a V-shaped impedance change characteristic with respect to a magnetic field as shown in FIG. For this purpose, as shown in FIG. 24, a bias magnet 17 is arranged on the back surface of the magnetic detection unit 14 so that a bias magnetic field of about 10 gauss (G) is applied to the detection unit 16. The range of good linearity is about ± 3 gauss (G) across the bias operating point in the case of the magnetic detection unit 14.

  FIG. 26 shows data obtained by measuring the current when the primary conductor 1 is energized with an AC current (50 Hz) variable from 0.1 to 40 Arms. 10 Arms is a sine wave of 28.28 App, and the magnetic field at that time is 724 mGpp from the simulation result. FIG. 15 shows an error between the ideal value and the actual measurement value with reference to 10 Arms, and the upper limit is set to 40 Arms because the adjustment is made so that 1 Vpp is obtained at 10 Arms with a 5 V power source. As accuracy, an error within ± 1% is guaranteed at 0.2 Arms or more.

  In the case where the diameter of the through hole 13 is 2 mm and the linearity range of the magnetic detection unit 14 is 6 gauss (G), the diameter exceeds 80 Arms. If it is possible to deal with up to 200 Arms, the magnetic field applied to the magnetic detection unit 14 is reduced to 1/3 only by setting the diameter of the through hole 13 to 1 mm, and a large current such as 270 Arms can be obtained with the same layout. On the contrary, the specification of small current can be dealt with by simply increasing the through hole 13.

  In the second embodiment, it is assumed that the primary conductor 12 is arranged on the sensor substrate 11. However, as shown in the modification of FIG. 27, in the case of the bus bar 19 in which the primary conductor is made of a copper plate, a module obtained by removing the primary conductor 12 from the configuration of FIG. 24 can be modularized on the sensor substrate 20. In this case, it is possible to position the sensor substrate 20 in the through hole 21 formed in the bus bar 19 and fix the sensor substrate 20 to the bus bar 19 by bonding or the like. In addition, 22 is a circuit element provided on the sensor substrate 20, and 23 is a signal line for extracting a signal of the magnetic detection unit 14.

  With such a configuration, even after the bus bar 19 is laid in advance, the magnetic detection unit 14 can be modularized and assembled to the bus bar 19 for easy assembly.

  In each of the above-described embodiments, the current is diverted by providing a non-conductive region with a through hole and a notch hole, but the current can be diverted by arranging an insulating material instead of the hole. .

<Example 3>
According to Japanese Patent Laid-Open No. 2006-184269, a proposal has been made to avoid a disturbance magnetic field by differential detection by using two magnetic detection elements. In this patent document, in order to avoid the influence of the external magnetic field when the magnetic field detection by the measured current is detected by a single magnetic sensor, an opening is formed in the central portion of the bus bar as the primary conductor to measure the measured current. Is diverted. In the opening, magnetic detection elements are arranged in the vicinity of the two conductors so that the magnetic fields from the currents have opposite phases, and only the magnetic field generated from the bus bar is detected by differential amplification.

  However, even if this method can eliminate the influence on the uniform magnetic field, if the current lines flow adjacently, the two magnetic sensing elements are not equally applied with the disturbance magnetic field. A magnetic shield is indispensable. As a method for solving this problem, the first and second embodiments have proposed that a non-conductive region is provided in the primary conductor and that one magnetic sensing element is provided in the vicinity of the non-conductive region. Here, a plurality of magnetic sensing elements may be provided. Therefore, in the third embodiment, a plan for providing a plurality of magnetic sensing elements will be described.

  FIG. 28 is a configuration diagram of a basic current sensor of Example 3 that performs current measurement on a current to be measured. A current to be measured I to be detected flows through the primary conductor 1, and the primary conductor 1 is in the form of, for example, a bus bar formed of a copper foil pattern or a copper plate on a printed board.

  Near the center of the primary conductor 1, a circular through hole 2 which is a non-conductive region is provided in order to partially block the current. For this reason, a part of the current I to be measured is as shown in FIG. A detour current Ia that goes around the outside symmetrically on both sides of the through hole 2 is obtained. For convenience of explanation, a coordinate axis is set for the primary conductor 1, the center of the through hole 2 is set as the origin O, the main direction in which the current I to be measured flows is the Y axis, the width direction that is the orthogonal axis is the X axis, and the thickness The direction is the Z axis.

  On the primary conductor 1, two magnetic detection elements 3a and 3b are arranged in series in the Y-axis direction to perform differential detection. The detection units 4a and 4b of the magnetic detection elements 3a and 3b are arranged such that the Y-axis direction is the magnetic field detection direction, and the center positions of the detection units 4a and 4b are distances dx and Y in the X-axis direction from the center of the through hole 2. In the axial direction, it is arranged at a position shifted by a distance dy across the X axis. As shown in FIG. 28, even if the primary conductor 1 ′ through which currents of different phases flow is close and the direction of the proximity current I ′ is parallel to the current I to be measured, the influence of the magnetic field due to the magnetic flux F of the proximity current I ′ is It becomes a vector component in the X-axis direction and has no Y-axis direction component. When the magnetic field detection direction of the detection units 4a and 4b is taken in the Y-axis direction, the magnetic detection elements 3a and 3b are not affected by the magnetic field due to the proximity current I 'and can detect only the vector component Hy of the current I to be measured. Therefore, if the vector component Hy is calibrated and converted, the amount of current I to be measured can be obtained.

  Since it is not desirable to detect the magnetic field vector component Hx in the X-axis direction as the magnetic sensing elements 3a and 3b to be used, a highly directional magnetic impedance element or orthogonal fluxgate element is suitable. An element is used. Magnetic thin film patterns are arranged in parallel in the Y-axis direction of the magnetic field detection direction as the detection units 4a and 4b, a high frequency pulse in the MHz band is applied to the electrodes 5 at both ends, and from both ends of the detection units 4a and 4b due to a change in magnetic field Is obtained as a sensor signal.

  As shown in FIG. 30, the height h of the detection portions 4a and 4b of the magnetic detection elements 3a and 3b with respect to the primary conductor 1 is necessary because of the structure that holds the positional relationship between the primary conductor 1 and the magnetic detection elements 3a and 3b. It is determined by the relationship between dielectric strength such as space, space distance, and creepage distance.

  FIG. 31 shows a configuration diagram of the detection circuit 100A. The detection units 4a and 4b of the magnetic detection elements 3a and 3b are connected to a resistor R that forms a bridge with respect to the CR pulse oscillation circuit 30. After the amplitude change from the voltage across the detection units 4a and 4b is taken out by the detection circuit 31, the differential amplification circuit 32 performs differential amplification on the outputs of the detection units 4a and 4b, and outputs the current sensor output. obtain.

In this case, the outputs of the detection units 4a and 4b have the same sensitivity and have the same absolute value if they are located symmetrically across the X axis, and have different polarities. This is twice the absolute value of the part 4a or 4b. In addition, the external magnetic field noise is in phase with the detection units 4a and 4b in a narrow range, and by detecting the outputs of the detection units 4a and 4b differentially, the magnetic field noise is canceled and superimposed on the output of the current sensor. In other words, only the vector component Hy of the bypass current is measured. In order to detect the output of the magnetic detection element differentially, at least two detection units may be used.
As apparent from a comparison between FIG. 31 and FIG. 15, the four resistors forming the bridge circuit are replaced with the detection unit. For example, if three detection units are employed, three of the four resistors are replaced with the detection unit. Furthermore, if four detection units are employed, all the resistances are replaced with detection units.

  In FIG. 28, the magnetic detection elements 3a and 3b are provided in the first and fourth quadrants on the XY plane, respectively. However, it is also possible to arrange them adjacent to other quadrants due to symmetry.

  FIG. 32 shows a modification in this case, and the same result is obtained even when the magnetic detection element 3a is provided in the first quadrant and the magnetic detection element 3b is provided in the second quadrant and arranged symmetrically with respect to the Y axis. It is done. The magnetic field vector component Hc1 due to the detour current Ia is a target with respect to the Y axis in the first quadrant and the second quadrant. Therefore, the magnetic detection elements 3a and 3b can be arranged in the first quadrant and the second quadrant, respectively, and the vector components Hy in the Y-axis direction having the same absolute value and the opposite polarity can be detected. In this case, although it is slightly affected by the adjacent current lines, the magnetic field noise can be substantially canceled by differential detection because the distance between the magnetic detection elements 3 is narrow.

<Example 4>
When the detection magnetic field range must be managed within a certain range in terms of magnetic saturation and linearity, such as a magnetic impedance element or an orthogonal fluxgate sensor which is a magnetic detection element, the primary conductor 1 It is preferable that the measurement range can be adjusted only by the diameter of the through hole 2.

  FIG. 33 is a configuration diagram of the current sensor of the fourth embodiment. Since the distance between the detection portions 4a and 4b of the magnetic detection elements 3 and 4 in FIG. 28 is short, a magnetic detection unit in which magnetic detection elements 3a and 3b arranged symmetrically with respect to the X axis are attached to the same element substrate 6 as an integrated type. The variation in performance can be suppressed.

  As shown in the modification of FIG. 34, the idea is to use only the positive region of the X-axis of the primary conductor 1, and the bypass current can be used by providing the notch hole 8 at the end in the width direction. With this cutout hole 8, measurement can be performed in the same manner as in the case where the through hole 2 is provided as shown in FIG. In order to flow the bypass current symmetrically with respect to the X axis, the notch hole 8 needs to be symmetrical with respect to the X axis.

  FIG. 35 is a configuration diagram of another modification. In the magnetic detection unit 7 in which the four magnetic detection elements 3a to 3d are integrated, the detection units 4a, 4b, 4c, and 4d are arranged in the first, second, third, and fourth quadrants, respectively, and a bridge is formed by the four elements. When operated as a configuration, the S / N can be further improved. As described above, when the detection units 4a to 4d are arranged symmetrically with respect to the X axis and the Y axis on both sides of the through hole 2, the vector component Hy is symmetrical with respect to the X axis and the Y axis, respectively.

  Therefore, differential detection of the outputs of the detection units 4a and 4d with respect to the X axis, differential detection of the detection units 4b and 4c, differential detection of the detection units 4a and 4b with respect to the Y axis, and differential detection of the detection units 4d and 4c. The measurement accuracy can be further improved by obtaining the average of these detection results.

<Example 5>
FIG. 36 is a configuration diagram of the current sensor according to the third embodiment. A primary conductor 12 made of a copper pattern having a width of 10 mm in the X-axis direction, a thickness of 70 μm in the Z-axis direction, and a longitudinal direction of 50 mm in the Y-axis direction is provided on one surface of the sensor substrate 11 made of glass epoxy material having a thickness of 1.6 mm. ing. A through hole 13 having a diameter of 2 mm is formed by etching in the center of the primary conductor 12 in the X-axis direction. On the other surface of the sensor substrate 11, an integrated magnetic detection unit 14 is disposed at the same position as in FIG. 33, and electrodes 15 a to 15 c for soldering are drawn out on the sensor substrate 11.

  The magnetic detection unit 14 uses a magneto-impedance element, and the detection units 16a and 16b made of an Fe-Ta-C magnetic thin film have eleven elongated portions each having a width of 18 μm, a thickness of 2.65 μm, and a length of 1.2 mm. Are arranged in parallel. And the magnetic field detection direction of the detection parts 16a and 16b is made into the Y-axis direction.

  The positions of the detectors 16a and 16b are offset from the center of the through-hole 13 by a distance dx = 1.5 mm in the X-axis direction, the center interval of the detectors 16a and 16b is dy = 3 mm, and the center O of the through-hole 13 is set. Are arranged symmetrically with respect to the X axis extending in the width direction.

  Although not shown, the plurality of magnetic thin film patterns of the detectors 16a and 16b are electrically connected in series in a zigzag manner, and both ends are connected to respective electrodes, and electrodes 15a to 15c on the sensor substrate 11 are connected. And is connected to a sensor circuit (not shown). In FIG. 36, a high frequency pulse is applied by the flow of the electrodes 15a → 15c and the electrodes 15b → 15c drawn to the sensor substrate 11.

  The magnetic detection unit 14 is provided with an easy magnetization axis in the width direction in the X-axis direction, and by passing a high-frequency pulse to the magnetic thin film pattern, the impedance is changed by an external magnetic field, and the voltage across the magnetic detection unit 14 is changed. The sensor signal is converted by amplitude detection.

  In the evaluation of the influence of currents other than the current I to be measured flowing in parallel, a copper rod 18 having a diameter of 2 mm is disposed in parallel with a distance of 10 mm from the primary conductor 12, and a current I ′ of 50 Arms of 10 Arms is flowed. The measurement was performed under the condition that no current was passed through the conductor 12. Then, in the magnetic detection unit 14, the influence of the current I ′ flowing through the copper rod 18 was not observed, and it was below the noise level (10 mVpp or below). The magnetic field from the adjacent parallel current lines is in the X or Z axis direction, does not have a component in the Y axis direction, and the distance between the detection units 16a and 16b and the adjacent copper rod 18 is equal. Worked effectively, and it was confirmed that the influence of the noisy magnetic field was almost completely eliminated.

  In Example 5, the example which has arrange | positioned the primary conductor 12 on the sensor board | substrate 11 was assumed. However, in the case of the bus bar 19 in which the primary conductor is made of a copper plate as shown in the modification of FIG. 37, a module obtained by removing the primary conductor 12 from the configuration of FIG. 36 can be modularized on the sensor substrate 20. In this case, it is possible to position the sensor substrate 20 in the through hole 21 formed in the bus bar 19 and fix the sensor substrate 20 to the bus bar 19 by bonding or the like. In addition, 22 is a circuit element provided on the sensor substrate 20, and 23 is a signal line for extracting a signal of the magnetic detection unit 14.

  With such a configuration, even after the bus bar 19 is laid in advance, the magnetic detection unit 14 can be modularized and assembled to the bus bar 19 for easy assembly.

  In each of the above-described embodiments, the current is diverted by providing a non-conductive region with a through hole and a notch hole, but the current can be diverted by arranging an insulating material instead of the hole. . These non-conductive regions need to be symmetrical on both sides with respect to the X axis.

<Example 6>
In Examples 1 to 5, a non-conductive region is employed as the direction change region. That is, the first to fifth embodiments are inventions that detect a distorted magnetic field generated when a current flows around a non-conductive region and estimate the amount of current from the detected magnetic field. A common concept in the first to fifth embodiments is to provide a region in the primary conductor that promotes a non-linear flow of current. In other words, the non-conductive region is not necessarily required as long as the current flowing direction can be bent. Accordingly, in the sixth embodiment, another example of the direction change area will be described.

  FIG. 38 is a configuration diagram of a basic current sensor of Example 6 that performs current measurement on a current to be measured. A current to be measured I to be detected flows through the primary conductor 1. The form of the primary conductor 1 is, for example, a form of a bus bar formed of a copper foil pattern or a copper plate on a printed board.

  A portion (main portion) of the primary conductor 1 that is a magnetic field detection target is a rectangular portion having a length L and a width W0. In the main part, an inlet 9a and an outlet 9b having widths W1 and W2 are formed at the rear and the front where current flows, respectively. The widths W1 and W2 are both narrower than the width W0. In order to make the explanation easy to understand, the inlet 9a and the outlet 9b are installed in the center with respect to the width W0.

  A coordinate axis is set for the primary conductor 1. Here, the center of the magnetic detection unit is the origin O. As shown in FIGS. 38 and 39, a line connecting the inlet 9a and the outlet 9b, which is an intersection of a straight line that divides the width W0 of the magnetic detection unit into two and a straight line that divides the length L of the magnetic detection unit into two. Is the origin O. As in the other examples, the main direction in which the current I to be measured flows is the Y axis, the width direction that is the orthogonal axis is the X axis, and the thickness direction is the Z axis.

  On the primary conductor 1, two magnetic detection elements 3a and 3b are arranged in series in the Y-axis direction to perform differential detection. Note that the number of magnetic sensing elements may be one as in the first and second embodiments. The configuration of the magnetic detection elements 3a and 3b is the same as in the first to fifth embodiments. The detection units 4a and 4b of the magnetic detection elements 3a and 3b are arranged such that the Y-axis direction is the magnetic field detection direction, and the magnetic detection elements 3a and 3b are arranged. The center positions of the detectors 4a and 4b are arranged at positions shifted from the center of the origin O by a distance dx in the X-axis direction and distances dy1 and dy2 with the X-axis in the Y-axis direction.

  Originally, the magnetic flux generated by the current is directed in the direction orthogonal to the current direction. Therefore, a magnetic field HC1 having only a vector component Hx in the X-axis direction on the X-axis passing through the origin O, where there is no current component facing in the width direction of the primary conductor 1 is generated.

  However, the current at a position shifted in the front-rear direction where the current flows from the origin O has a current component that flows toward the inlet 9a and the outlet 9b in an inclined manner with respect to the Y-axis direction. As a result, a vector component Hy in the Y-axis direction is generated, and the magnetic field meanders like Hc2 and Hc3. The magnetic fields of Hc2 and Hc3 are line symmetric with respect to the X axis. The vector component Hy has a reverse polarity across the X axis.

  As shown in FIG. 38, even if the primary conductor 1 ′ through which currents of different phases flow is close and the direction of the proximity current I ′ is parallel to the current I to be measured, the influence of the magnetic field by the proximity current I ′ is in the X-axis direction. Vector component and no Y-axis direction component. When the magnetic field detection direction of the detection units 4a and 4b is taken in the Y-axis direction, the magnetic detection elements 3a and 3b are not affected by the magnetic field due to the proximity current I 'and can detect only the vector component Hy of the current I to be measured. Therefore, if the vector component Hy is calibrated and converted, the amount of current I to be measured can be obtained.

  When the magnetic detection elements 3a and 3b detect the magnetic field vector component Hx in the X-axis direction, the current estimation accuracy decreases. For this reason, examples of the magnetic sensing elements 3a and 3b include a highly directional magnetic impedance element and an orthogonal fluxgate element. In the sixth embodiment, magnetic impedance elements are used as the magnetic detection elements 3a and 3b. Magnetic thin film patterns are arranged side by side in the Y-axis direction of the magnetic field detection direction as the detection units 4a and 4b. A high frequency pulse in the MHz band is applied to the electrodes 5 at both ends, and a change in voltage amplitude from both ends of the detection units 4a and 4b due to a change in the magnetic field is obtained as a sensor signal. When a bias magnetic field is required, although not shown, it is applied by a magnet or a wound coil adjacent to the magnetic sensing elements 3a and 3b.

  As shown in FIG. 40, the height h of the detection portions 4a and 4b of the magnetic detection elements 3a and 3b with respect to the primary conductor 1 is, for example, the adjustment of the magnitude of the generated magnetic field, and the position of the primary conductor 1 and the magnetic detection elements 3a and 3b. It is determined by the relationship of dielectric strength such as the space necessary for the structure to maintain the relationship, the spatial distance, and the creepage distance.

  The configuration of the detection circuit 100A that functions as a current detection device can employ the circuit configuration shown in FIG. This is because the basic part of the current detection device of the present invention can be used as it is even if the specific configuration of the region direction changing region for changing the direction of current flow is changed.

  41, FIG. 42, FIG. 43 and FIG. 44, and FIG. 45 show the simulation results of the magnetic field component Hy in the Y-axis direction related to the diffusion current from the narrow entrance / exit. The primary conductor 1 has a cross section with a width W0 = 8 mm in the X-axis direction and a thickness t = 0.8 mm in the Z-axis direction. The distance L between the inlet 9a and the outlet 9b is 7.5 mm, and the position in the width direction is the width W0. In the center of The width of the inlet 9a and the outlet 9b is set to W1 = W2 = d, and d = 0.8, 1.2, 2.4, 3.6 mm, and the surface of the primary conductor (height H = 1.6 mm) The magnetic field Hy in the main direction through which the current flows was calculated. The measured current I was 1 ampere (A).

  41 to 41D show simulation results for d = 0.8, 1.2, 2.4, and 3.6 mm, respectively. The coordinates are the first quadrant of X ≧ 0 and Y ≧ 0, and the contours are drawn in 10% increments with the vertex of the vector component Hy being 100%. In the other quadrants, a magnetic field distribution symmetric with respect to the X axis or the Y axis is formed, the third quadrant has the same polarity as the first quadrant, and the second and fourth quadrants have a magnetic field having the opposite polarity to the first quadrant.

  The peak position P is almost unchanged at 2.5 mm in the Y direction, and moves slowly from 1.7 mm to 2.15 mm in the X direction as the width of the entrance / exit increases.

  Let the distance in the Y direction from the doorway be L. The peak position P is 1.25 (= L / 2−2.5) mm at L = 7.5 mm, but it is 1.35 mm even when calculated at L = 11.5 mm, and both are not greatly changed. . The dimension of the practical distance L is determined in consideration of the fact that a peak can be clearly formed and does not interfere with an adjacent peak in reverse phase. For example, the distance L should be secured 5 mm or more, which is four times 1.25 mm.

  FIG. 45 is a graph showing the magnetic field Hy at the peak position. According to FIG. 45, when the ratio between the widths W1 and W0 of the inlet 9a and the outlet 9b is 10% (W0 = 8 mm, d = 0.8 mm), a magnetic field of 0.08 gauss per 1 A is generated. Recognize. A magnetic sensing element capable of detecting milligauss or less can detect a small target current of 1 A or less with sufficient S / N by placing it at the peak position.

  When the widths W1 and W2 of the inlet 9a and the outlet 9b are increased, the current component spreading in the width direction is reduced, and the magnetic field Hy is rapidly reduced. Therefore, in order to detect a large current, the widths W1 and W2 may be widened. When the ratio between the widths W1 and W0 is 100%, that is, d = 8 mm, the magnetic field becomes zero. This means that the adjustment range for a large current can be widened. From the above, if the magnetic sensing element is fixed at X = 2 mm and Y = 2.5 mm, it means that it is possible to meet the specifications of various current detection ranges simply by changing the widths W1 and W2.

  Such characteristics are extremely convenient for elements that must manage the detection magnetic field range within a certain range in terms of magnetic saturation and linearity, such as magneto-impedance elements and orthogonal fluxgate sensors. . In terms of productivity, it is possible to meet various current specifications by fixing the position of the element and changing the width of the entrance and exit of the primary conductor, greatly contributing to the cost reduction of the current sensor. Let's go.

  In FIG. 38, the magnetic detection elements 3a and 3b are provided in the first and fourth quadrants on the XY plane, respectively. However, of course due to symmetry, it can also be placed adjacent to other quadrants. FIG. 46 shows an example in which the magnetic detection element 3a is arranged in the first quadrant and the magnetic detection element 3b is arranged in the second quadrant. FIG. 47 shows an example in which magnetic detection elements are provided in all quadrants.

  In FIG. 47, in the magnetic detection element unit in which the four magnetic detection elements 3a to 3d are integrated, the detection units 4a, 4b, 4c, and 4d are arranged in the first, second, third, and fourth quadrants, respectively. Yes. Furthermore, when the detection units 4a, 4b, 4c, and 4d are operated as a bridge configuration as shown in FIG. 31, the S / N of the detection circuit 100A can be improved. As described above, when the detectors 4a to 4d are arranged symmetrically with respect to the X axis and the Y axis on both sides of the two origins O, the vector component Hy is symmetrical with respect to the X axis and the Y axis, respectively.

  Therefore, differential detection of the outputs of the detection units 4a and 4d with respect to the X axis, differential detection of the detection units 4b and 4c, differential detection of the detection units 4a and 4b with respect to the Y axis, and differential detection of the detection units 4d and 4c. The measurement accuracy can be further improved by obtaining the average of these detection results.

  When the inlet 9a and the outlet 9b are in the center of the primary conductor 1 in the width direction, the primary conductor 1 can be differentially operated by symmetrically installing elements whose sensitivity of the elements are adjusted to be equal to each other in the X axis or Y axis. The output from the magnetic field is doubled, and the external magnetic field having the same phase is canceled.

  FIG. 48 shows a modification. If the width of the conductor reaching the inlet 9a or the width of the conductor after the outlet 9b is too thin, a problem of heat generation may occur when a large current is applied. Therefore, as shown in FIG. 48, by restricting the current inlet / outlet with the slit grooves 7a, 7b, 7c, 7d, heat generation itself can be suppressed and thermal diffusion can be improved. 48, it can be understood that the main portion, the inlet 9a, and the outlet 9b described above are formed by inserting the slit grooves 7a, 7b, 7c, and 7d in the primary conductor 1. FIG.

<Example 7>
In the sixth embodiment, if the detection portions 4a and 4b of the magnetic detection elements 3a and 3b are placed in the vicinity of (2, 2.5) and (2, -2.5) in the coordinate positions, the inlet 9a and the outlet 9b It was shown that the specification of the current to be measured can be accommodated only by changing the widths W1, W2. As another method, the arrangement positions of the inlet 9 a and the outlet 9 b may be offset in the width direction of the primary conductor 1. FIG. 49 shows the layout. In the layout of FIG. 39, the entrance 9a and the exit 9b are shifted by dw in the width direction. Thereby, since the spread of the current changes, the direction of the magnetic field at the position where the detection units 4a and 4b of the magnetic detection elements 3a and 3b are arranged can be changed.

  FIG. 50 shows the result of a simulation of the magnetic field component Hy in the Y-axis direction for Example 7. The width W0 = 8 mm in the X-axis direction of the primary conductor 1 and the thickness t = 0.8 mm in the Z-axis direction. The inlet 9a and outlet 9b are both 1.2 mm in width W1 and W2. The length L in the Y-axis direction of the primary conductor 1 that is a magnetic detection unit is set to 7.5 mm. In the state where the positions of the inlet 9a and the outlet 9b are in the center of the width W0 as in the sixth embodiment, the offset amount dw = 0. In Example 7, the simulation was performed for each of the offset amounts dw = −2, −1, 0, 1, and 2 mm.

  The coordinate position of the magnetic detection element 3a is fixed to X = 2 and Y = 2.5 mm. As shown in FIG. 50, the magnetic field of the magnetic field component Hy in the direction in which the current mainly flows has less adjustment white when the offset amount becomes negative. On the other hand, when the offset amount becomes positive, that is, when the distance between the entrance 9a and the exit 9b and the magnetic sensing element is shortened, the magnetic field is rapidly reduced to the opposite polarity. Therefore, in the region where the offset amount is positive, the magnetic field component Hy can be significantly adjusted.

<Example 8>
FIG. 51 is a configuration diagram of the current sensor of the eighth embodiment. The sensor substrate 11 is made of a glass epoxy material and has a thickness of 1.6 mm. A primary conductor 12 is provided on one side of the sensor substrate 11. The primary conductor 12 is a copper pattern having a width of 8 mm in the X-axis direction, a length of 7.5 mm in the Y-axis direction, and a thickness of 70 μm in the Z-axis direction. The origin O of the X and Y axes is set at the center of the primary conductor 12.

  The inlet 9a and the outlet 9b of the primary conductor 12 are drawn from the center of the width W in the X-axis direction along the Y axis with a width W1 = W2 = 1.2 mm. If the inlet 9a and the outlet 9b are pulled out for a long time with a width of 1.2 mm, heat may be generated on the large current side. Therefore, in the experiment, a cable wire having a core wire diameter of 1.6 mm was soldered in the immediate vicinity of the inlet 9a and the outlet 9b, and a current to be measured was applied.

  On the other surface of the sensor substrate 11, a magnetic detection unit 14 in which two magnetic detection elements are integrated is disposed. From the magnetic detection unit 14, electrodes 15 a to 15 c for soldering are drawn on the sensor substrate 11.

  A magnetic impedance element is used for the magnetic detection unit 14. The detectors 16a and 16b made of a Fe-Ta-C magnetic thin film are constituted by eleven patterns arranged in parallel in a narrow shape having a width of 18 μm, a thickness of 2.65 μm, and a length of 1.2 mm. And the magnetic field detection direction of the detection parts 16a and 16b is made into the Y-axis direction.

  As shown in FIG. 51, the positions of the detection units 16a and 16b are offset from the center of the through hole 13 by a distance dx = 2 mm in the X-axis direction. The center interval dy between the detectors 16a and 16b is 5 mm. As described above, the magnetic detection unit 14 is disposed symmetrically with respect to the X axis.

  The plurality of magnetic thin film patterns of the detectors 16a and 16b are not shown in the figure but are electrically connected in series by zigzag folding. Both ends of the magnetic thin film pattern connected in series are connected to respective electrodes. As shown in FIG. 51, the ends of the magnetic thin film pattern are soldered to the electrodes 15a to 15c on the sensor substrate 11 and connected to the detection circuit 100A. In FIG. 51, a high frequency pulse is applied with the electrode 15a to the electrode 15c drawn to the sensor substrate 11 and the electrode 15b to the electrode 15c as a pair.

  The magnetic detection unit 14 is provided with an easy magnetization axis in the X-axis direction (width direction). By applying a high-frequency pulse to the pattern of the magnetic thin film, the impedance is changed by an external magnetic field, and the voltage across the magnetic detection unit 14 is converted into a sensor signal by amplitude detection. If the bias magnetic field and circuit gain of each element are matched so that there is no relative difference, the effect of differential detection is enhanced.

  In the evaluation of the influence of currents other than the current I to be measured flowing in parallel, a copper rod 18 having a diameter of 2 mm was arranged in parallel with a distance of 10 mm from the end of the primary conductor 12. Measurement was performed under the condition that a current I 'of 10 Arms and 50 Hz was passed through the copper rod 18 and no current was passed through the primary conductor 12. In the magnetic detection unit 14, the influence of the current I ′ flowing through the copper rod 18 is less than the noise level (10 mVpp or less). The magnetic field from adjacent parallel current lines is in the X or Z axis direction, does not have a component in the Y axis direction, and the distance between the detection units 16a and 16b and the adjacent copper rod 18 is equal, so that differential removal is performed. It was confirmed that the function worked effectively and the influence of the noisy magnetic field was almost completely eliminated.

  FIG. 52 shows the relationship between the measured current and the output voltage when the width W1 (= W2) of the inlet 9a and outlet 9b of the primary conductor 1 is 1.2 mm and 4.8 mm. Since the detection circuit 100A is driven by a single power source of 5V, the output voltage for the measurement current 0A is adjusted to 2.5V.

  As shown in FIG. 45, the magnetic field Hy in the Y direction applied to the element is 0.078 gauss per 1A, and in the sensor in which the above linearity is ensured within a range of ± 3 gauss, it exceeds ± 38.5A. Linearity will decrease. It can be seen from the actual measurement data shown in FIG. 52 that the straight line accuracy decreases from around 40A. Under this condition, the specification is ± 40A.

  In order to widen the range with good linearity, the width of the inlet 9a and the outlet 9b may be increased. When the widths W1 and W2 are set to 4.8 mm, the magnetic field Hy is 0.038 gauss per 1A, and linear accuracy is ensured up to ± 79A. You can see that The difference in sensitivity may be adjusted by the gain of differential amplification.

  This means that the linearity accuracy can be secured in a desired measurement current range by changing the width of the current inlet / outlet with the same magnetic sensing element and circuit configuration to be used.

  As described above, the current detection circuits described in the first to eighth embodiments can be very small in size as compared with a current transformer or the like. Therefore, it can be sufficiently incorporated into the AC inlet 140 as described in the embodiments A to C.

Claims (21)

AC inlet into which the power cable is plugged,
A pair of input terminals for inputting current through the power cable;
A terminal holding portion for holding the pair of input terminals;
A pair of output terminals for outputting the current input by the pair of input terminals;
An insulating portion provided at an end of the terminal holding portion on the pair of output terminals side;
A current path provided on one side of the insulating portion to connect the pair of input terminals and the pair of output terminals;
An AC inlet, comprising: a magnetic detection element that is provided on the other surface side of the insulating portion and detects a magnetic field generated from the current path.   2. The AC inlet according to claim 1, wherein the one surface of the insulating portion and the other surface of the insulating portion are two surfaces formed in the insulating portion along the insertion direction of the power cable.   3. The AC inlet according to claim 1, wherein the insulating portion protrudes from the end portion of the terminal holding portion toward the pair of output terminals and is provided integrally with the insulating portion.   The current path and the magnetic sensing element are covered with a case, the insulating part functions as a partition part that partitions the space inside the case into a first space and a second space, and the current path is formed in the first space. The AC inlet according to any one of claims 1 to 3, wherein the AC inlet is disposed and the magnetic sensing element is disposed in the second space.   The AC inlet according to claim 4, wherein the case includes a shield case. AC inlet into which the power cable is plugged,
A pair of input terminals for inputting current through the power cable;
A terminal holding portion for holding the pair of input terminals;
A pair of output terminals for outputting the current input by the pair of input terminals;
A current path connecting the pair of input terminals and the pair of output terminals;
A magnetic sensing element for sensing a magnetic field generated from the current path;
A case covering the current path and the magnetic sensing element;
A partition member that partitions the interior of the case into a plurality of rooms,
An AC inlet, wherein the current path is arranged on one side of the partition member inside the case, and the magnetic sensing element is arranged on the other side of the partition member inside the case. AC inlet into which the power cable is plugged,
A pair of input terminals for inputting current from outside through the power cable; and
A terminal holding portion for holding the pair of input terminals;
A shield case disposed behind the terminal holding portion in the direction of pulling out the power cable;
A pair of output terminals for outputting the current input from the pair of input terminals to the outside of the shield case;
A current path connecting the pair of input terminals and the pair of output terminals;
A partition member that partitions the inside of the shield case into a plurality of rooms;
A magnetic sensing element that is provided in a second room different from the first room through which the current path passes among the plurality of rooms and that detects a magnetic field generated from the current path is provided. AC inlet.   The AC inlet according to claim 6 or 7, wherein the partition member is an insulator and a nonmagnetic material.   The AC inlet according to claim 7 or 8, wherein the second room is mounted with a low-power component that operates by being supplied with a direct current. Leg members attached to the partition member in the second chamber;
A circuit board supported by the leg member,
The AC inlet according to any one of claims 7 to 9, wherein the magnetic sensing element is mounted on the circuit board.   8. The second room is provided with a conductor for connecting a ground input terminal surrounded by the terminal holding portion and a ground output terminal exposed to the outside of the shield case. The AC inlet according to any one of 1 to 10. A voltage detection circuit for detecting a voltage applied to the pair of input terminals;
The voltage detection circuit is
A first voltage dividing element having one end connected to the first input terminal of the pair of input terminals;
A second voltage dividing element having one end connected to a second input terminal of the pair of input terminals;
The AC inlet according to any one of claims 7 to 11, wherein the AC inlet is provided. The first voltage dividing element and the second voltage dividing element are provided in the first chamber;
The partition member is provided with a hole through which the other end of the first voltage dividing element and the other end of the second voltage dividing element are inserted.
The other end of the first voltage dividing element is connected to one end of a third voltage dividing element in the second chamber;
The other end of the second voltage dividing element is connected to one end of the fourth voltage dividing element in the second chamber,
In the second chamber, a voltage divided by the first voltage dividing element and the third voltage dividing element, a voltage divided by the second voltage dividing element and the fourth voltage dividing element, The AC inlet according to claim 12, further comprising a differential amplifier circuit that differentially amplifies the AC inlet.   14. The AC inlet according to claim 12, further comprising a power determination circuit that determines power from a current detected by the magnetic detection element and a voltage detected by the voltage detection circuit.   The AC inlet according to claim 1, wherein the magnetic sensing element is a magnetic impedance element, a fluxgate sensor, or a giant magnetoresistive element. AC inlet into which the power cable is plugged,
A pair of input terminals for inputting current from outside through the power cable; and
A terminal holding portion for holding the pair of input terminals;
A shield case disposed behind the terminal holding portion in the direction of pulling out the power cable;
A pair of output terminals for outputting the current input by the pair of input terminals;
A current path connecting the pair of input terminals and the pair of output terminals;
A partition member that partitions the inside of the shield case into a plurality of rooms;
A voltage detection circuit for detecting a voltage applied to the pair of input terminals,
The voltage detection circuit is
A first voltage dividing element having one end connected to the first input terminal of the pair of input terminals;
A second voltage dividing element having one end connected to a second input terminal of the pair of input terminals;
With
The AC inlet, wherein the first voltage dividing element and the second voltage dividing element are provided in a first room through which the current path passes among the plurality of rooms. The first voltage dividing element and the second voltage dividing element are provided in the first chamber;
The partition member is provided with a hole through which the other end of the first voltage dividing element and the other end of the second voltage dividing element are inserted.
The other end of the first voltage dividing element is connected to one end of a third voltage dividing element in a second chamber different from the first chamber;
The other end of the second voltage dividing element is connected to one end of the fourth voltage dividing element in the second chamber,
In the second chamber, a voltage divided by the first voltage dividing element and the third voltage dividing element, a voltage divided by the second voltage dividing element and the fourth voltage dividing element, The AC inlet according to claim 16, further comprising a differential amplifier circuit that differentially amplifies the signal. A current detection device attached to an AC inlet into which a power cable is inserted, wherein the AC inlet includes a pair of input terminals for inputting current from the outside through the power cable, and a terminal holding unit for holding the pair of input terminals. With
The current detector is
A shield case disposed behind the terminal holding portion in the direction of pulling out the power cable;
A pair of output terminals for outputting the current input from the pair of input terminals to the outside of the shield case;
A current path connecting the pair of input terminals and the pair of output terminals;
A partition member that partitions the inside of the shield case into a plurality of rooms;
A magnetic sensing element that is provided in a second room different from the first room through which the current path passes among the plurality of rooms and that detects a magnetic field generated from the current path is provided. Current detection device. A voltage detection device attached to an AC inlet into which a power cable is inserted, wherein the AC inlet includes a pair of input terminals for inputting current from the outside through the power cable, and a terminal holding unit for holding the pair of input terminals. With
A shield case disposed behind the terminal holding portion in the direction of pulling out the power cable;
A pair of output terminals for outputting the current input from the pair of input terminals to the outside of the shield case;
A current path connecting the pair of input terminals and the pair of output terminals;
A partition member that partitions the inside of the shield case into a plurality of rooms;
A voltage detection circuit for detecting a voltage applied to the pair of input terminals,
The voltage detection circuit is
A first voltage dividing element having one end connected to the first input terminal of the pair of input terminals;
A second voltage dividing element having one end connected to a second input terminal of the pair of input terminals;
With
The voltage detection device, wherein the first voltage dividing element and the second voltage dividing element are provided in a first room through which the current path passes among the plurality of rooms.   An electronic apparatus comprising the AC inlet according to claim 1. An AC inlet according to any one of claims 1 to 17,
A power strip comprising: at least one outlet for outputting a current supplied from the AC inlet.

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