Current sensor

Abstract

To provide a current sensor that offers redundancy and saves space.SOLUTION: A current detector is provided, comprising a busbar 2 through which a measurement target current I flows, the busbar consisting of a left busbar 20, a center busbar 21, and a right busbar 22. A first shunt resistor 3A and a second shunt resistor 3B, serving as multiple current sensors of the same type for detecting the current I, are provided on a flow path, on the busbar 2, of the current I flowing from a right-hand side face 22d toward the left-hand side face 20c of the busbar 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a current detector. [Background technology]

[0002] Conventionally, a shunt resistor (see, for example, Patent Document 1) is known as a contact-type current sensor, and a magnetic sensor (see, for example, Patent Document 2) is known as a non-contact-type current sensor.

[0003] In recent years, there has been an increasing demand for redundancy so that current detection can continue even if one current sensor is damaged.

[0004] In order to meet such demands, a method has been proposed in which multiple current sensors are arranged in parallel to provide redundancy (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-190543 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-014477 [Patent Document 3] Japanese Patent Publication No. 2020-091261 Summary of the Invention [Problem to be solved by the invention]

[0006] However, although the above method can provide redundancy, it requires a large installation space.

[0007] In view of the above problems, an object of the present invention is to provide a current detector that can provide redundancy and can save space. [Means for solving the problem]

[0008] The above object of the present invention can be achieved by the following means: Note that the parentheses indicate reference symbols of embodiments to be described later, but the present invention is not limited to these.

[0009] According to the invention of claim 1, the measuring device has a bus bar (2) through which a current (I) to be measured flows, a plurality of current sensors (e.g., shunt resistors 3 shown in FIG. 1 ) of the same type that detect the current (I) are provided on a path of the bus bar (2) through which the current (I) flows from one end face (right side face 22 d) of the bus bar (2) to the other end face (left side face 20 c) of the bus bar (2); The busbars include a first busbar (left busbar 20), a second busbar (center busbar 21), and a third busbar (right busbar 22), The plurality of current sensors are configured with a first shunt resistor (3A) and a second shunt resistor (3B), The first shunt resistor (3A) is A first resistor (30A), a pair of first measurement terminals (31A), the first resistor (30A) is joined between the first bus bar (left bus bar 20) and the second bus bar (center bus bar 21); the pair of first measurement terminals (31A) are provided on the first bus bar (left bus bar 20) and the second bus bar (center bus bar 21), respectively; The second shunt resistor (3B) is A second resistor (30B), a pair of second measurement terminals (31B), the second resistor (30B) is joined between the second bus bar (center bus bar 21) and the third bus bar (right bus bar 22), the pair of second measurement terminals (31B) are provided on the second bus bar (center bus bar 21) and the third bus bar (right bus bar 22), respectively; When the current (I) flows from one end face (right side face 22d) of the third bus bar (right bus bar 22), the current (I) flows to the other end face (left side face 22c) of the third bus bar (right bus bar 22), and further, the current (I) flows to one end faces (right side faces 21d and 20d) of the second bus bar (central bus bar 21) and the first bus bar (left bus bar 20), and the current (I) flows to the other end face (left side face 20c) of the first bus bar (left bus bar 20). As a result, since the current (I) flows through the first resistor (30A), the first shunt resistor (3A) detects the magnitude of the current from the voltage across the first resistor (30A), and further, since the current (I) also flows through the second resistor (30B), the second shunt resistor (3B) detects the magnitude of the current from the voltage across the second resistor (30B). [Effects of the Invention]

[0010] Next, the effects of the present invention will be described with reference to the drawings. Note that the reference symbols in parentheses are those of the embodiments described below, but the present invention is not limited to these.

[0011] According to the invention of claim 1, a plurality of current sensors of the same type (e.g., shunt resistors 3 shown in FIG. 1 ), each consisting of a first shunt resistor 3A and a second shunt resistor 3B, are provided on the path of the bus bar 2 along which the current I to be measured flows from one end face (right side face 22d) of the bus bar 2 to the other end face (left side face 20c) of the bus bar 2. This allows for redundancy so that current detection can continue even if one current sensor is damaged, as in the prior art. Furthermore, since a plurality of current sensors of the same type are provided on a single bus bar 2, it is possible to reduce the installation space. Thus, the invention of claim 1 allows for redundancy and space savings. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1(a) is a perspective view of a current detector according to a first embodiment of the present invention, and FIG. 1(b) is a longitudinal sectional view of the current detector according to the same embodiment. [Figure 2] FIG. 6(a) is a perspective view of a current detector according to a second embodiment of the present invention, and FIG. 6(b) is a longitudinal sectional view of the current detector according to the same embodiment. [Figure 3] FIG. 10(a) is a perspective view of a current detector according to a third embodiment of the present invention, and FIG. 10(b) is a longitudinal sectional view of the current detector according to the same embodiment. [Figure 4] FIG. 10 is a perspective view of a current detector according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] <Description of First Embodiment> A first embodiment of a current detector according to the present invention will now be described in detail with reference to Fig. 1. In the following description, when directions such as up, down, left, and right are indicated, they refer to up, down, left, and right when viewed from the front of the figure.

[0014] The current detector according to this embodiment is used in inverters, batteries, etc., and as shown in Fig. 1, the current detector 1 is composed of a bus bar 2 and a plurality of shunt resistors 3. Each component will be described in detail below.

[0015] <Busbar Description> The busbar 2 is made of a metal such as copper and, as shown in Fig. 1, is in the form of a thick plate with a thickness of, for example, about 3 mm to 5 mm, and is composed of a left busbar 20, a central busbar 21, and a right busbar 22. As shown in Fig. 1(a), the left busbar 20 is formed in an elongated rectangular shape with an upper surface 20a, a lower surface 20b, a left side surface 20c, and a right side surface 20d. As shown in Fig. 1(b), a circular left through-hole 20e (see Fig. 1(a)) is provided on the left side surface 20c of the left busbar 20, penetrating from the upper surface 20a to the lower surface 20b of the left busbar 20, for allowing the shank of a bolt (not shown) to pass therethrough.

[0016] On the other hand, as shown in Fig. 1(a), the central bus bar 21 is formed in a long rectangular shape with an upper surface 21a, a lower surface 21b, a left side surface 21c, and a right side surface 21d. Furthermore, as shown in Fig. 1(a), the right bus bar 22 is formed in a long rectangular shape with an upper surface 22a, a lower surface 22b, a left side surface 22c, and a right side surface 22d. As shown in Fig. 1(b), a circular right through-hole 22e (see Fig. 1(a)) is provided on the right side surface 22d of the right bus bar 22, penetrating from the upper surface 22a to the lower surface 22b of the right bus bar 22 for passing a shank of a bolt (not shown).

[0017] <Explanation of shunt resistor> The shunt resistor 3 is a contact-type current sensor that passes the current flowing through the bus bar 2 described above through a resistor and detects the magnitude of the current from the voltage across the resistor. More specifically, as shown in Fig. 1, the shunt resistor 3 is composed of a first shunt resistor 3A and a second shunt resistor 3B. The first shunt resistor 3A is composed of a first resistor 30A and a first measurement terminal 31A. As shown in Fig. 1(a), the first resistor 30A is formed in the shape of a short, thick rectangular plate with a thickness of approximately 3 mm to 5 mm, and is made of, for example, a Cu-Mn alloy, a Cu-Ni alloy, a Ni-Cr alloy, or the like. 1, the left side surface 30Aa of the first resistor 30A is joined to the right side surface 20d of the left bus bar 20 by welding Y1, and the right side surface 30Ab of the first resistor 30A is joined to the left side surface 21c of the central bus bar 21 by welding Y1. As a result, the first resistor 30A is sandwiched between the left bus bar 20 and the central bus bar 21, and is formed integrally with the bus bar 2.

[0018] On the other hand, the first measurement terminals 31A are capable of mounting a printed circuit board (not shown) for current detection and are formed of copper, tin-plated material, or the like. As shown in FIG. 1, a pair of first measurement terminals 31A are provided, each of which further includes a rod-shaped first shaft portion 31Aa. This first shaft portion 31Aa is a voltage measurement terminal used to measure current values and has a diameter of, for example, approximately 1 mm to 1.5 mm. As shown in FIG. 1(b), the lower surface 31Aa1 of the first shaft portion 31Aa of one of the pair of first measurement terminals 31A contacts the upper surface 20a of the right side surface 20d of the left bus bar 20, and the outer circumferential surface of the first shaft portion 31Aa on the lower surface 31Aa1 side is joined by welding Y2. As a result, as shown in FIG. 1, the first shaft portion 31Aa of one of the pair of first measurement terminals 31A is provided upright on the upper surface 20a of the right side surface 20d of the left bus bar 20.

[0019] 1(b), the lower surface 31Aa1 of the first shaft portion 31Aa of the other of the pair of first measurement terminals 31A contacts the upper surface 21a on the left side surface 21c side of the central bus bar 21, and the outer circumferential surface of the first shaft portion 31Aa on the lower surface 31Aa1 side is joined by welding Y2. As a result, as shown in FIG. 1, the first shaft portion 31Aa of the other of the pair of first measurement terminals 31A is provided upright on the upper surface 21a on the left side surface 21c side of the central bus bar 21.

[0020] Thus, as shown in FIG. 1(a), the first shunt resistor 3A is provided on the path of the busbar 2 through which the current I flows. Specifically, when the current I to be measured flows through the busbar 2, which is installed in an inverter, battery, or the like, from the right side surface 22d of the right busbar 22 to the left side surface 20c of the left busbar 20, as shown in FIG. 1(a), the current I flows through the first resistor 30A of the first shunt resistor 3A. This generates a voltage (potential difference) across both ends of the first resistor 30A, i.e., the left side surface 30Aa and the right side surface 30Ab, and this voltage (potential difference) is detected by the pair of first measurement terminals 31A. A current-detection printed circuit board (not shown) mounted on the pair of first measurement terminals 31A converts the voltages detected by the pair of first measurement terminals 31A into currents, thereby enabling the current values to be measured.

[0021] On the other hand, as shown in FIG. 1, the second shunt resistor 3B is composed of a second resistor 30B and a second measurement terminal 31B. As shown in FIG. 1(a), the second resistor 30B is formed in the shape of a short, thick, rectangular plate with a thickness of approximately 3 mm to 5 mm, for example, and is made of, for example, a Cu-Mn alloy, a Cu-Ni alloy, or a Ni-Cr alloy. As shown in FIG. 1, the left side surface 30Ba of the second resistor 30B is joined to the right side surface 21d of the central bus bar 21 by welding Y3, and the right side surface 30Bb of the second resistor 30B is joined to the left side surface 22c of the right bus bar 22 by welding Y3. As a result, the second resistor 30B is sandwiched between the central bus bar 21 and the right bus bar 22 and is formed integrally with the bus bar 2.

[0022] On the other hand, the second measurement terminals 31B are capable of mounting a printed circuit board (not shown) for current detection and are formed of copper, tin-plated material, or the like. As shown in FIG. 1, a pair of second measurement terminals 31B are provided, each of which further includes a rod-shaped second shaft portion 31Ba. This second shaft portion 31Ba is a voltage measurement terminal used to measure current values and has a diameter of, for example, approximately 1 mm to 1.5 mm. As shown in FIG. 1(b), the lower surface 31Ba1 of the second shaft portion 31Ba of one of the pair of second measurement terminals 31B contacts the upper surface 21a on the right side surface 21d of the central busbar 21, and the outer circumferential surface of the second shaft portion 31Ba on the lower surface 31Ba1 side is joined by welding Y4. As a result, as shown in FIG. 1, the second shaft portion 31Ba of one of the pair of second measurement terminals 31B is provided upright on the upper surface 21a on the right side surface 21d of the central busbar 21.

[0023] 1(b), the lower surface 31Ba1 of the second shaft portion 31Ba of the other of the pair of second measurement terminals 31B contacts the upper surface 22a on the left side surface 22c side of the right bus bar 22, and the outer circumferential surface of the second shaft portion 31Ba on the lower surface 31Ba1 side is joined by welding Y4. As a result, as shown in FIG. 1, the second shaft portion 31Ba of the other of the pair of second measurement terminals 31B is provided upright on the upper surface 22a on the left side surface 22c side of the right bus bar 22.

[0024] Thus, as shown in FIG. 1(a), the second shunt resistor 3B is disposed on the path of the busbar 2 through which the current I flows. Specifically, when the current I to be measured flows through the busbar 2, which is installed in an inverter, battery, or the like, from the right side surface 22d of the right busbar 22 to the left side surface 20c of the left busbar 20, as shown in FIG. 1(a), the current I flows through the second resistor 30B of the second shunt resistor 3B. This generates a voltage (potential difference) across both ends of the second resistor 30B, i.e., the left side surface 30Ba and the right side surface 30Bb. This voltage (potential difference) is detected by the pair of second measurement terminals 31B. A current detection printed circuit board (not shown) mounted on the pair of second measurement terminals 31B converts the voltages detected by the pair of second measurement terminals 31B into currents, thereby enabling the current values to be measured.

[0025] Therefore, in this embodiment, a plurality of current sensors (shunt resistors 3) for detecting the current I are provided on the path of one bus bar 2, that is, the bus bar 2 through which the current I to be measured flows, from the right side surface 22d of the right bus bar 22 toward the left side surface 20c of the left bus bar 20. This provides redundancy so that current detection can continue even if one current sensor is damaged, as in the conventional case.

[0026] Furthermore, in this embodiment, it is possible to reduce the installation space because multiple current sensors (shunt resistors 3) are provided on one bus bar 2. That is, in the past, multiple current sensors were simply arranged in parallel, which posed a problem of requiring a large installation space, but in this embodiment, multiple current sensors (shunt resistors 3) are provided on one bus bar 2, which makes it possible to reduce the installation space.

[0027] Therefore, according to this embodiment, redundancy can be provided and space can be saved.

[0028] <Description of Second Embodiment> Next, a second embodiment of the current detector according to the present invention will be described in detail with reference to Fig. 2. In the following description, when directions such as up, down, left, and right are indicated, they refer to up, down, left, and right when viewed from the front of the figure. The same components as those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0029] The current detector according to this embodiment, like the first embodiment, is used in inverters, batteries, etc., and as shown in Fig. 2, the current detector 1A is composed of a bus bar 2A and a plurality of magnetic sensors 4. Each component will be described in detail below.

[0030] <Busbar Description> The busbar 2A is made of a metal such as copper and has a thick plate shape with a thickness of, for example, about 3 mm to 5 mm, as shown in Fig. 2(a). As shown in Fig. 2(b), a circular left through-hole 2Ae1 (see Fig. 1(a)) is provided on the left side 2Ac side, penetrating from the upper surface 2Aa to the lower surface 2Ab of the busbar 2A for allowing the shank of a bolt (not shown) to pass therethrough. Furthermore, as shown in Fig. 2(b), a circular right through-hole 2Ae2 (see Fig. 1(a)) is provided on the right side 2Ad side, penetrating from the upper surface 2Aa to the lower surface 2Ab of the busbar 2A for allowing the shank of a bolt (not shown) to pass therethrough.

[0031] <Magnetic sensor explanation> The magnetic sensor 4 is a non-contact current sensor that detects magnetic field components generated by the current I (see FIG. 2(a)) flowing through the bus bar 2A described above. Explaining in more detail, as shown in FIG. 2, the magnetic sensor 4 is composed of a first magnetic sensor 4A and a second magnetic sensor 4B. As shown in FIG. 2(a), the first magnetic sensor 4A is composed of a first element substrate 40A having a short, horizontally elongated rectangular shape, and a first IC chip 41A such as a Hall element or a magnetoresistance element that is disposed on an upper surface 40Aa of the first element substrate 40A.

[0032] Thus, as shown in FIG. 2, the first magnetic sensor 4A is disposed slightly toward the left side surface 2Ac from the center of the bus bar 2A. More specifically, as shown in FIG. 2(b), the first magnetic sensor 4A is disposed in a position floating above the bus bar 2A so as not to contact the upper surface 2Aa of the bus bar 2A, i.e., in a position spaced apart vertically upward (upward in the figure) from the bus bar 2A. To fix this position, as shown in FIG. 2(b), a first resin 5A having a rectangular cross section is disposed to fill the gap between the lower surface 40Ab of the first element substrate 40A of the first magnetic sensor 4A and the upper surface 2Aa of the bus bar 2A. The lower surface 40Ab of the first element substrate 40A and the upper surface 2Aa of the bus bar 2A are molded or resin-cased with the first resin 5A. As a result, the first magnetic sensor 4A is disposed in a position floating above the bus bar 2A so as not to contact the upper surface 2Aa of the bus bar 2A, as shown in FIG. 2(b).

[0033] Thus, as shown in Fig. 2(a), the first magnetic sensor 4A is provided on the path of the bus bar 2A through which the current I flows. That is, when the current I to be measured flows through the bus bar 2A, which is installed in an inverter, a battery, or the like, from the right side surface 2Ad to the left side surface 2Ac as shown in Fig. 2(a), a first magnetic field component M1 is generated in a direction perpendicular to the current I flowing through the bus bar 2A. At this time, the first IC chip 41A of the first magnetic sensor 4A detects this first magnetic field component M1, thereby enabling the current value to be measured.

[0034] On the other hand, as shown in Figure 2(a), the second magnetic sensor 4B is composed of a short, horizontally elongated rectangular second element substrate 40B and a second IC chip 41B such as a Hall element or a magnetic resistance element arranged on the upper surface 40Ba of this second element substrate 40B.

[0035] Thus, as shown in FIG. 2, the second magnetic sensor 4B is disposed slightly toward the right side surface 2Ad from the center of the bus bar 2A. More specifically, as shown in FIG. 2(b), the second magnetic sensor 4B is disposed in a position floating above the bus bar 2A so as not to contact the upper surface 2Aa of the bus bar 2A, i.e., in a position spaced apart vertically upward (upward in the figure) from the bus bar 2A. To fix this position, as shown in FIG. 2(b), a second resin 5B having a rectangular cross section is disposed to fill the gap between the lower surface 40Bb of the second element substrate 40B of the second magnetic sensor 4B and the upper surface 2Aa of the bus bar 2A, and the lower surface 40Bb of the second element substrate 40B and the upper surface 2Aa of the bus bar 2A are molded or resin-cased with the second resin 5B. As a result, the second magnetic sensor 4B is disposed in a position floating above the bus bar 2A so as not to contact the upper surface 2Aa of the bus bar 2A, as shown in FIG. 2(b).

[0036] Thus, as shown in Fig. 2(a), the second magnetic sensor 4B is provided on the path of the bus bar 2A through which the current I flows. That is, when the current I to be measured flows through the bus bar 2A, which is installed in an inverter, battery, or the like, from the right side surface 2Ad to the left side surface 2Ac as shown in Fig. 2(a), a second magnetic field component M2 is generated in a direction perpendicular to the current I flowing through the bus bar 2A. At this time, the second IC chip 41B of the second magnetic sensor 4B detects this second magnetic field component M2, thereby enabling the current value to be measured.

[0037] Therefore, in this embodiment, a plurality of current sensors (magnetic sensors 4) for detecting the current I are provided on the path of one bus bar 2A, that is, the bus bar 2A through which the current I to be measured flows from the right side surface 2Ad to the left side surface 2Ac. This also makes it possible to provide redundancy so that current detection can continue even if one current sensor is damaged, as in the conventional case.

[0038] Furthermore, in this embodiment as well, a plurality of current sensors (magnetic sensors 4) are provided on one bus bar 2A, so that the installation space can be reduced.

[0039] Therefore, in this embodiment as well, redundancy can be provided and space can be saved.

[0040] <Description of the Third Embodiment> Next, a third embodiment of a current detector according to the present invention will be described in detail with reference to Fig. 3. The current detector 1 in the first embodiment and the current detector 1A in the second embodiment are examples in which the same current sensor, i.e., a plurality of current sensors of the same current detection method, are provided on one bus bar, but the third embodiment is an example in which current sensors of different current detection methods are provided on one bus bar.

[0041] That is, the current detector of this embodiment is used in inverters, batteries, etc., just like the first and second embodiments, and as shown in Figure 3, the current detector 1B is composed of a busbar 2B, a first shunt resistor 3A, and a first magnetic sensor 4A.

[0042] 3, the busbar 2B is made up of a left busbar 20 and a right busbar 22. The right side surface 20d of the left busbar 20 is joined to the left side surface 30Aa of the first resistor 30A by welding Y1, and the left side surface 22c of the right busbar 22 is joined to the right side surface 30Ab of the first resistor 30A by welding Y1. As a result, the first resistor 30A is sandwiched between the left busbar 20 and the right busbar 22, and is formed integrally with the busbar 2B.

[0043] Furthermore, as shown in FIG. 3 , the first shaft portion 31Aa of one of the pair of first measurement terminals 31A is provided upright on the top surface 20a of the right side surface 20d of the left busbar 20 by welding Y2. Furthermore, as shown in FIG. 3 , the first shaft portion 31Aa of the other of the pair of first measurement terminals 31A is provided upright on the top surface 22a of the left side surface 22c of the right busbar 22 by welding Y2. As a result, the first shunt resistor 3A is provided on the path of the busbar 2B through which the current I flows, as shown in FIG. 3(a). That is, when the current I to be measured flows through the busbar 2B, which is installed in an inverter, battery, or the like, from the right side surface 22d of the right busbar 22 toward the left side surface 20c of the left busbar 20, as shown in FIG. 3(a), the current I flows through the first resistor 30A of the first shunt resistor 3A. This generates a voltage (potential difference) across both ends of the first resistor 30A, i.e., the left side surface 30Aa and the right side surface 30Ab, and this voltage (potential difference) is detected by each of the pair of first measurement terminals 31A. As a result, a printed circuit board (not shown) for current detection mounted on the pair of first measurement terminals 31A converts the voltages detected by the pair of first measurement terminals 31A into currents, thereby making it possible to measure the current values.

[0044] 3, the first magnetic sensor 4A is provided slightly toward the right side surface 22d from the center of the right bus bar 22. More specifically, as shown in FIG. 3(b), the first magnetic sensor 4A is disposed in a position floating above the right bus bar 22 so as not to come into contact with the upper surface 22a of the right bus bar 22, i.e., in a position spaced apart in a vertically upward direction (upward in the figure) from the right bus bar 22. To fix this position, as shown in FIG. 3(b), a first resin 5A having a rectangular cross-section is disposed so as to fill the gap between the lower surface 40Ab of the first element substrate 40A of the first magnetic sensor 4A and the upper surface 22a of the right bus bar 22, and the lower surface 40Ab of the first element substrate 40A and the upper surface 22a of the right bus bar 22 are molded or resin-cased with the first resin 5A. As a result, the first magnetic sensor 4A is disposed at a position above the right bus bar 22 so as not to come into contact with the upper surface 22a of the right bus bar 22, as shown in FIG. 3(b).

[0045] Thus, as shown in Fig. 3(a), the first magnetic sensor 4A is provided on the path of the bus bar 2B through which the current I flows. That is, when the current I to be measured flows through the bus bar 2B, which is installed in an inverter, battery, or the like, from the right side surface 22d of the right bus bar 22 to the left side surface 20c of the left bus bar 20, as shown in Fig. 4(a), a first magnetic field component M1 is generated in a direction perpendicular to the current I flowing through the bus bar 2B. At this time, the first IC chip 41A of the first magnetic sensor 4A detects this first magnetic field component M1, thereby enabling the current value to be measured.

[0046] Therefore, in this embodiment, a plurality of current sensors (first shunt resistor 3A, first magnetic sensor 4A) for detecting current I are provided on the path of one bus bar 2B, that is, bus bar 2B through which current I to be measured flows from the right side surface 22d of right bus bar 22 toward the left side surface 20c of left bus bar 20. This configuration also provides redundancy so that current detection can continue even if one current sensor is damaged, as in the conventional case.

[0047] Furthermore, in this embodiment as well, a single bus bar 2B is provided with a plurality of current sensors (first shunt resistor 3A, first magnetic sensor 4A), so that the installation space can be reduced.

[0048] Therefore, in this embodiment as well, redundancy can be provided and space can be saved.

[0049] <Description of Modifications> The current detectors 1, 1A, and 1B described in the first to third embodiments are merely examples, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. For example, the current detector 1 described in the first embodiment includes two shunt resistors 3, but the number of shunt resistors 3 is not limited to two and may be three or more. Furthermore, the current detector 1A described in the second embodiment includes two magnetic sensors 4, but the number of shunt resistors 3 is not limited to two and may be three or more. Furthermore, the current detector 1B described in the third embodiment includes only one first shunt resistor 3A and one first magnetic sensor 4A, but the number of shunt resistors 3A and 1B may be one second shunt resistor 3B or one second magnetic sensor 4B. Furthermore, multiple first shunt resistors 3A (second shunt resistors 3B) and multiple first magnetic sensors 4A (second magnetic sensors 4B) may be provided, or other current sensors may be provided.

[0050] The shapes of the busbars 2, 2A, and 2B illustrated in the first to third embodiments are merely examples, and any shape may be used. For example, in the present embodiment, the left through-holes 20e and 2Ae1 and the right through-holes 22e and 2Ae2 are provided, but these may not be provided. Furthermore, the busbars may be U-shaped, U-shaped, or shaped like the busbar 2C shown in FIG. 4. This point will be explained in detail using FIG. 4. The following description will be given using an example in which the busbar 2B shown in the third embodiment is modified, but it goes without saying that this can also be applied to the busbar 2 shown in FIG. 1 and the busbar 2A shown in FIG. 2. The same components as those in the current detector 1B shown in FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0051] The current detector 1C shown in Fig. 4 is identical to the current detector 1B shown in Fig. 3 except for the shape of the busbars. Specifically, the busbar 2C shown in Fig. 4 is made of a metal such as copper and includes a left busbar 20 and a right busbar 22C. The right busbar 22C has a bent shape, with the left side surface 22Cc of the right busbar 22C being linear from the center to the left side surface 22Cc, but being bent upward from the center to the right side surface 22Cd. The left side surface 22Cc of the right busbar 22C is joined to the right side surface 30Ab of the first resistor 30A by welding Y1. Furthermore, the first shaft portion 31Aa of the first measurement terminal 31A is provided upright on the top surface 22Ca of the right bus bar 22C on the left side surface 22Cc side by welding Y2, and the first magnetic sensor 4A is provided on the linear portion extending from the center of the right bus bar 22C toward the left side surface 22Cc side. Therefore, even with this shape of the bus bar 2C, it is possible to provide redundancy and achieve space saving.

[0052] While FIG. 4 illustrates an example in which the first magnetic sensor 4A is provided on a straight portion extending from the center of the right bus bar 22C toward the left side surface 22Cc, the present invention is not limited to this configuration and the first magnetic sensor 4A may be provided on a bent portion. However, it is preferable to provide the first magnetic sensor 4A on a straight portion. This is because the first magnetic sensor 4A, including the second magnetic sensor 4B, requires treatment such as shielding to prevent erroneous measurements or providing a casing to prevent physical damage. However, this treatment is difficult when the first magnetic sensor 4A (second magnetic sensor 4B) is provided on a bent portion. Therefore, it is preferable to provide the first magnetic sensor 4A (second magnetic sensor 4B) on a straight portion, as this facilitates treatment such as providing a shield or a casing. [Explanation of symbols]

[0053] 1 Current detector 2 busbars 20 Left bus bar (first bus bar) 20c Left side (other end side) 20d Right side (one end side) 21 Central bus bar (second bus bar) 21d Right side (one end side) 22 Right bus bar (third bus bar) 22c Left side (other end side) 22d Right side (one end side) 3 Shunt resistor (current sensor) 3A 1st shunt resistor 3B Second shunt resistor 30A First Resistor 31A 1st measurement terminal 30B 2nd resistor 31B 1st measurement terminal I current

Claims

[Claim 1] A bus bar through which the current to be measured flows is provided. a plurality of current sensors of the same type are provided on a path of the bus bar along which the current flows from one end surface side to the other end surface side of the bus bar, and the current sensors detect the current; the bus bars include a first bus bar, a second bus bar, and a third bus bar; the plurality of current sensors are configured with a first shunt resistor and a second shunt resistor; The first shunt resistor is A first resistor; a pair of first measurement terminals; the first resistor is joined between the first bus bar and the second bus bar, the pair of first measurement terminals are provided on the first bus bar and the second bus bar, respectively; The second shunt resistor is A second resistor; a pair of second measurement terminals; the second resistor is joined between the second bus bar and the third bus bar, the pair of second measurement terminals are provided on the second bus bar and the third bus bar, respectively; When the current flows from one end surface of the third bus bar, the current flows to the other end surface of the third bus bar, and further, current flows to one end surfaces of the second bus bar and the first bus bar, and the current flows to the other end surface of the first bus bar. As a result, since the current flows through the first resistor, the first shunt resistor detects the magnitude of the current from the voltage across the first resistor, and further, since the current also flows through the second resistor, the second shunt resistor detects the magnitude of the current from the voltage across the second resistor, forming a current detector.

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