JP2023004468A - current detector - Google Patents

Abstract

A current detection device capable of suppressing the influence of a magnetic field generated by a current flowing through each bus bar on a current detection sensor and improving the accuracy of current detection is provided. Kind Code: A1 A current detector is provided with a bus bar mounted between a three-phase motor and a three-phase inverter to allow current to flow from the three-phase inverter to the three-phase motor, and a current detection sensor capable of detecting the current flowing through the bus bar. In the device, the busbar has a first busbar 2a, a second busbar 2b, and a third busbar 2c formed in a flat plate shape, and the first busbar 2a, the second busbar 2b, and the third busbar 2c have an insulating member 3 interposed therebetween. The laminated component Y is formed as an integral laminated component Y, and the current detection sensor 4 is arranged at a lateral position of the laminated component Y. As shown in FIG. [Selection drawing] Fig. 2

Description

The present invention relates to a current detection device having a busbar attached between a three-phase motor and a three-phase inverter, and a magnetic detection sensor capable of detecting current flowing through the busbar.

A current detection device connected between a three-phase motor and a three-phase inverter includes a bus bar for passing current from the three-phase inverter to the three-phase motor, and a magnetic detection sensor capable of detecting the current flowing through the bus bar. Proposed. A bus bar in such a current detection device is made up of three plate-like metal members connected for each of the U/V/W phases, and is designed to allow current to flow from the 3-phase inverter to the 3-phase motor.

In a conventional current detection device, for example, as disclosed in Patent Document 1, three busbars of U/V/W phases are laminated with an insulating member interposed to form an integrated laminated component. , current detection sensors (IC chips) are disposed on the upper surface of the upper busbar and the lower surface of the lower busbar, respectively, so that the currents flowing through the upper and lower busbars can be detected by the current detection sensors.

JP 2020-118629 A

However, in the above-described conventional current detection device, the busbars are laminated to form an integral laminated part, and the current detection sensors are arranged on the upper surface of the upper busbar and the lower surface of the lower busbar. The current detection sensor is affected by the magnetic field generated by the current flowing through each bus bar, and there is a possibility that the accuracy of current detection is lowered. In particular, since a relatively large current flows through the bus bar in order to drive a three-phase motor, the effect of the magnetic field generated by the current is great.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and is a current detection device capable of suppressing the influence of the magnetic field generated by the current flowing through each bus bar on the current detection sensor and improving the current detection accuracy. is to provide

The invention according to claim 1 comprises: a bus bar mounted between a three-phase motor and a three-phase inverter for passing a current from the three-phase inverter to the three-phase motor; and a current detection sensor capable of detecting the current flowing through the bus bar. wherein the bus bar has a first bus bar, a second bus bar, and a third bus bar formed in a flat plate shape, and the first bus bar, the second bus bar, and the third bus bar have an insulating member interposed therebetween. It is characterized in that they are laminated while being stacked to form an integral laminated component, and the current detection sensor is arranged at a position on the side of the laminated component.

The invention according to claim 2 is the current detection device according to claim 1, wherein the current detection sensor is capable of detecting the strength of the magnetic field generated by the current shunted from the current flowing through the bus bar. It is characterized in that the current flowing through the bus bar can be detected based on the strength of the magnetic field.

According to a third aspect of the present invention, there is provided a current detection device according to the second aspect, wherein at least two of the first, second and third busbars have sub-busbars projecting sideways from side surfaces thereof. , wherein the current detection sensor is capable of detecting the current shunting and flowing in the sub-bus bar.

The invention according to claim 4 is the current detection device according to claim 3, wherein the current detection sensor is attached to a printed circuit board on which an electric circuit is printed, and the printed circuit board is attached to the side surface of the laminated component. It is characterized by

According to a fifth aspect of the present invention, there is provided the current detecting device according to the fourth aspect, wherein the sub-busbar is composed of two projecting portions projecting apart from each other by a predetermined distance in the extending direction of the busbar, and is inserted into the printed circuit board. and connecting the printed circuit boards, and the current flowing through one of the protrusions flows through a predetermined electric circuit formed on the printed circuit board and flows to the other protrusion.

The invention according to claim 6 is the current detection device according to any one of claims 2 to 5, wherein the bus bar in which the sub bus bar is formed is formed with a slit for shunting current to the sub bus bar. characterized by

The invention according to claim 7 is the current detection device according to any one of claims 1 to 6, wherein the first bus bar, the second bus bar, and the third bus bar are arranged in three layers of an upper layer, a lower layer, and an intermediate layer. and the current detection sensor is positioned on the side of the bus bar of the intermediate layer.

According to the first aspect of the invention, the bus bar has a first bus bar, a second bus bar, and a third bus bar formed in a flat plate shape, and the first bus bar, the second bus bar, and the third bus bar have an insulating member interposed therebetween. Since the current detection sensor is arranged on the side of the laminated part, the current flowing through the first bus bar, the second bus bar, and the third bus bar It is possible to reliably cancel the magnetic fields generated respectively, suppress the influence of the magnetic fields generated by the currents flowing through the bus bars on the current detection sensor, and improve the current detection accuracy.

According to the invention of claim 2, the current detection sensor is capable of detecting the strength of the magnetic field generated by the current shunted from the current flowing through the bus bar, and detects the current flowing through the bus bar based on the strength of the detected magnetic field. Since it is detectable, it is possible to accurately detect the current flowing through the bus bar based on the relatively small current that is shunted.

According to the invention of claim 3, at least two of the first bus bar, the second bus bar, and the third bus bar are provided with sub-bus bars protruding sideways on the side surfaces of the bus bars, and the sub-bus bar divides the current flowing through the sub-bus bars. can be detected by the current detection sensor, the sub-busbar can divide the current into a relatively small current, and the current can be accurately detected by the current detection sensor based on the small divided current.

According to the fourth aspect of the invention, the current detection sensor is attached to the printed circuit board on which the electric circuit is printed, and the printed circuit board is attached to the side surface of the laminated component. can be done easily.

According to the invention of claim 5, the sub-bus bar is composed of two projecting parts projecting with a predetermined distance in the extending direction of the bus bar, and is inserted into the printed circuit board to connect the printed circuit board. can be accurately supported at a predetermined position on the side surface of the laminated part, and the current flowing through one projection flows through a predetermined electric circuit formed on the printed circuit board to the other projection. , a shunted current can flow through a predetermined electrical circuit on the printed circuit board.

According to the sixth aspect of the present invention, the busbar formed with the sub-busbar is formed with a slit for shunting the current to the sub-busbar, so that the sub-busbar can shunt the current more smoothly and accurately.

According to the seventh aspect of the invention, the first bus bar, the second bus bar, and the third bus bar are laminated in three layers, ie, the upper layer, the lower layer, and the intermediate layer, and the current detection sensor is disposed laterally of the intermediate bus bar. , the magnetic field generated by the current flowing through each bus bar can be canceled out more accurately, and the influence of the magnetic field generated by the current flowing through each bus bar on the current detection sensor can be reliably suppressed to detect the current. Accuracy can be improved.

1 is an overall perspective view showing a current detection device according to an embodiment of the present invention; FIG. Four views showing the same current detection device A perspective view showing laminated parts (state before the current detection sensor and the printed circuit board are attached) in the same current detection device. Three-sided view showing laminated parts of the same current detection device A perspective view showing a bus bar (first bus bar or second bus bar) in the same current detection device. A three-sided view showing the same bus bar The perspective view which shows the bus bar (3rd bus bar) in the current detection apparatus. A two-sided view showing the same bus bar The perspective view which shows the printed circuit board in the current detection apparatus. A two-sided view showing the same printed circuit board Graph showing the current detected by the current detection sensor in the same current detection device Schematic diagram showing the magnetic field generated at time t in FIG. Schematic diagram showing a connection relationship between a three-phase inverter and a three-phase motor to which the same current detection device is attached

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
As shown in FIG. 13, the current detection device 1 according to the present embodiment is attached inside the case of a three-phase inverter I, and from the three-phase inverter I, a U-phase coil, a V-phase coil and a W-phase coil of a three-phase motor M are detected. Alternating currents are supplied to the coils, respectively, and the motor M is driven by the rotating magnetic fields generated by the U-phase coil, the V-phase coil and the W-phase coil.

As shown in FIGS. 1 and 2, the current detection device 1 according to the present embodiment is attached between a three-phase motor M and a three-phase inverter I, and has a bus bar that allows current to flow from the three-phase inverter I to the three-phase motor M. (2a to 2c) and a current detection sensor 4 capable of detecting the current flowing through the busbars (2a to 2c). and a third bus bar 2c, and the first bus bar 2a, the second bus bar 2b, and the third bus bar 2c are laminated with the insulating member 3 interposed to form an integral laminated component Y.

As shown in FIGS. 5 and 6, the first bus bar 2a and the second bus bar 2b are formed by pressing a conductive metal such as copper into a flat plate shape. A sub-bus bar a2 and a slit b2 are formed in the slit b1 and the second bus bar 2b. The sub-busbars (a1, a2) protrude laterally from the respective side surfaces of the first busbar 2a and the second busbar 2b, and are separated by a predetermined distance from the extending direction B of the first busbar 2a and the second busbar 2b. It consists of two protrusions protruding from each other.

The sub-busbars (a1, a2) according to the present embodiment are composed of protrusions integrally formed with the first busbar 2a and the second busbar 2b, and can be formed integrally by trimming, for example, by pressing. It's becoming The sub-busbars (a1, a2) are separated and connected so as to protrude sideways from the side surfaces of the first busbar 2a and the second busbar 2b. The current may be shunted.

The slits (b1, b2) are formed in the width direction A in the first bus bar 2a and the second bus bar 2b on which the sub bus bars (a1, a2) are formed, and the current flowing through the first bus bar 2a and the second bus bar 2b is cut into the sub bus bar. (a1, a2). That is, the slits (b1, b2) are formed at positions corresponding to the sub-busbars (a1, a2) (positions adjacent to the sub-busbars (a1, a2) in this embodiment), and the current resistance is determined at that position. By increasing the current flowing through the first bus bar 2a and the second bus bar 2b, the current flowing through the sub bus bars (a1, a2) is divided.

As shown in FIGS. 7 and 8, the third bus bar 2c is formed by pressing a conductive metal such as copper into a flat plate shape. It has substantially the same rectangular shape as the bus bar 2a and the second bus bar 2b. Then, as shown in FIGS. 3 and 4, the first busbar 2a is the upper layer, the second busbar 2b is the lower layer, and the third busbar 2c is the intermediate layer, and the busbars 2a and 2c are stacked. A laminated component Y is formed by interposing an insulating member 3 between the second bus bar 2b and the third bus bar 2c.

In the laminated component Y, the sub-busbars a1 of the first busbars 2a and the sub-busbars a2 of the second busbars 2b are formed to protrude out of alignment with each other in the extending direction B, and the printed circuit board 5, which will be described later, is attached at each position. It's like The insulating member 3 is made of an insulating material, and the surface and the back surface thereof are coated with an adhesive substance. As a result, the first bus bar 2a, the second bus bar 2b, and the third bus bar 2c, which are laminated while being adhered to each other by the insulating member 3, are integrated to form an integral laminated component Y. As shown in FIG. Moreover, the first bus bar 2a, the second bus bar 2b, and the third bus bar 2c may be fixed by a resin holder or the like instead of the adhesion by the sticky substance.

Here, the current detection sensor 4 according to the present embodiment is disposed at a position on the side of the laminated component Y (the side face F1 or a position spaced laterally from the side face F1). is attached to the side F1 of the The current detection sensor 4 is a magnetic detection element (for example, MR (Magnet Resistance)) capable of detecting the strength of the magnetic field generated by the current shunted from the current flowing through the first busbar 2a and the second busbar 2b to the sub-busbars (a1, a2). A sensor, a GMR (Giant Magnet Resistive effect) sensor, etc.), and can detect the current flowing through the first bus bar 2a and the second bus bar 2b based on the strength of the detected magnetic field.

The current detection sensor 4 according to this embodiment is attached to a printed circuit board 5 on which an electric circuit is printed, and the printed circuit board 5 is attached to the side surface F1 of the laminated component Y. As shown in FIG. That is, as shown in FIGS. 1 and 2, the laminated component Y has two side faces F1 and F2 perpendicular to the width direction A, and the current detection sensor 4 is mounted on one of the side faces F1. A printed circuit board 5 is attached.

As shown in FIGS. 9 and 10, the printed circuit board 5 is formed with a pair of insertion holes 5a that match the sub-busbars (a1, a2) and can be inserted through. ), the printed circuit board 5 is connected to the laminated component Y. As shown in FIG. Therefore, the sub-busbars (a1, a2) have the function of passing the current flowing through the first busbar 2a and the second busbar 2b, and the function of supporting the printed circuit board 5 on which the current detection sensor 4 is mounted on the side surface F1 of the laminated component Y. It is considered to have

Furthermore, a predetermined electric circuit H is printed on the printed circuit board 5 for electrically connecting the sub-busbars (a1, a2) inserted through the insertion holes 5a. It is configured to flow through the electric circuit H of the second sub-busbar (a1, a2). A current detection sensor 4 detects a magnetic field generated by a current flowing from one of the sub-busbars (a1, a2) to the other sub-busbar (a1, a2) via a predetermined electric circuit H, thereby detecting the first busbar 2a. And the current flowing through the second bus bar 2b can be detected.

Furthermore, the current detection sensor 4 according to the present embodiment is positioned on the side of the third bus bar 2c, which is an intermediate layer forming the laminated component Y, as shown in FIG. That is, as shown in FIG. 2, in the printed circuit board 5 supported by the sub-busbar a1 of the first busbar 2a, the current detection sensor 4 is formed below the sub-busbar a1, and the sub-busbar a2 of the second busbar 2b is formed. In the printed circuit board 5 supported by , each current detection sensor 4 is positioned to the side of the third bus bar 2c by forming the current detection sensor 4 above the sub-bus bar a2.

Thus, by detecting the current flowing through the first bus bar 2a and the second bus bar 2b with the current detection sensor 4, the current flowing through the third bus bar 2c can also be calculated. In this embodiment, when an alternating current is passed through the three-phase motor M via the three-phase inverter I, as shown in FIG. 11, the U-phase current α , V-phase current β and W-phase current γ flow.

These U-phase current α, V-phase current β, and W-phase current γ are AC signals whose phases are shifted by 120°. It has become. However, around the current detector 1, for example, at time t, as shown in FIG. 12, a magnetic field G1 accompanying the U-phase current α and a magnetic field G2 accompanying the V-phase current β are generated (time t , the W-phase current γ is 0 and no magnetic field is generated), and the directions of the lines of magnetic force of the magnetic field G1 and the magnetic field G2 are opposite to each other.

Here, let G1a be the magnetic force line parallel to the width direction A of the laminated part Y in the magnetic field G1 (the magnetic force line at the upper or lower position), G1b be the magnetic force line parallel to the stacking direction C (the magnetic force line at the lateral position), Let G2a be the magnetic force line parallel to the width direction A of the laminated part Y in the magnetic field G2, and G2b be the magnetic force line parallel to the lamination direction C. It is difficult to cancel out the magnetic field because the strength differs depending on the separation dimension.

On the other hand, since the strength of the magnetic lines of force G1b and the lines of magnetic force G2b located on the sides of the laminated component Y are substantially equal regardless of the distance between the first bus bar 2a and the second bus bar 2b, the magnetic fields can be reliably canceled. can be done. Since the relational expression Iu+Iv+Iw=0 is satisfied, the relationship between the lines of magnetic force G1b and the lines of magnetic force G2b is as described above even at times other than time t. Therefore, in the current detection device 1 according to the present embodiment, since the current detection sensor 4 is arranged at a position on the side of the laminated component Y, the current flowing through the first busbar 2a, the second busbar 2b and the third busbar 2c is It is possible to reliably cancel the magnetic field generated by

According to this embodiment, the busbar has the first busbar 2a, the second busbar 2b and the third busbar 2c formed in a flat plate shape, and the first busbar 2a, the second busbar 2b and the third busbar 2c are The laminated component Y is formed by lamination with the insulating member 3 interposed therebetween, and the current detection sensor 4 is arranged at a lateral position of the laminated component Y. Therefore, the first bus bar 2a and the second bus bar The magnetic fields generated by the currents flowing through the busbars 2b and 2c can be reliably canceled, and the influence of the magnetic fields generated by the currents flowing through the busbars (2a, 2b, 2c) on the current detection sensor 4 can be reduced. can be suppressed, and the current detection accuracy can be improved.

Further, the current detection sensor 4 according to the present embodiment divides the current flowing through the busbars (the first busbar 2a and the second busbar 2b), and is capable of detecting the strength of the magnetic field generated by the divided current. Since the current flowing through the busbars (the first busbar 2a, the second busbar 2b, and the third busbar 2c) can be detected based on the strength of the detected magnetic field, the current flowing through the busbars can be detected based on the shunted relatively small current. can be detected with high accuracy.

Furthermore, sub-busbars protruding sideways are provided on the side surfaces of at least two busbars (the first busbar 2a and the second busbar 2b in this embodiment) among the first busbar 2a, the second busbar 2b and the third busbar 2c. (a1, a2) are formed, and the current detection sensor 4 can detect the current that is shunted by the sub-busbars (a1, a2). Based on the small shunt current, the current detection sensor 4 can accurately detect the current.

Furthermore, the current detection sensor 4 according to the present embodiment is attached to the printed circuit board 5 on which the electric circuit is printed, and the printed circuit board 5 is attached to the side face F1 of the laminated component Y. The assembly of the detection sensor 4 can be easily performed. In particular, in the present embodiment, the busbars (the first busbar 2a and the second busbar 2b) in which the sub-busbars (a1, a2) are formed have slits (b1, b2) is formed, the current can be shunted by the sub-busbars (a1, a2) more smoothly and accurately.

In addition, the sub-busbars (a1, a2) according to the present embodiment are composed of two projecting portions projecting with a predetermined distance in the extending direction B of the busbars (the first busbar 2a and the second busbar 2b), Since the printed circuit board 5 is inserted through and connected to the printed circuit board 5, the printed circuit board 5 can be accurately supported at a predetermined position on the side surface F1 of the laminated component Y, and the current flowing through one of the projecting portions of the printed circuit board 5 Since it is configured to flow through the predetermined electric circuit H formed on the printed circuit board 5 to the other projecting portion, the shunted current can flow through the predetermined electric circuit H of the printed circuit board 5 .

Further, the first bus bar 2a, the second bus bar 2b, and the third bus bar 2c are laminated in three layers of an upper layer, a lower layer, and an intermediate layer, and the current detection sensor 4 is the intermediate layer bus bar (in this embodiment, , and third busbars 2c), magnetic fields generated by currents flowing through the busbars (2a, 2b, 2c) can be canceled more accurately, and each busbar (2a, 2b, 2c) can be It is possible to reliably suppress the influence of the magnetic field generated by the flowing current on the current detection sensor 4 and improve the current detection accuracy.

The present embodiment has been described above, but the present invention is not limited to this. may be attached to the Further, the current detection sensor 4 according to the present embodiment is capable of detecting the strength of the magnetic field generated by the current shunted from the current flowing through the busbars (2a, 2b, 2c), and based on the strength of the detected magnetic field. Although the current flowing through the busbars (2a, 2b, 2c) can be detected by the detection of the current flowing through the busbars (2a, 2b, 2c), the current shunted from the current flowing through the busbars (2a, 2b, 2c) may be directly detected.

The bus bar has a first bus bar, a second bus bar, and a third bus bar formed in a flat plate shape, and the first bus bar, the second bus bar, and the third bus bar are laminated with an insulating member interposed to form an integral lamination. As long as it is a component and the current detection sensor is a current detection device arranged at a side position of the laminated component, it can be applied to a component having a different external shape or having other functions added. can be done.

1 current detection device 2a first bus bar (upper layer)
2b Second bus bar (lower layer)
2c third bus bar (middle layer)
3 Insulating member 4 Current detection sensor 5 Printed circuit board 5a Insertion holes a1, a2 Sub-bus bar (protrusion)
b1, b2 Slit Y Laminated parts F1, F2 Side face H Predetermined electric circuit M Three-phase motor I Three-phase inverter A Width direction B Extension direction C Lamination direction

Claims (7)

a bus bar attached between the three-phase motor and the three-phase inverter, for supplying current from the three-phase inverter to the three-phase motor;
a current detection sensor capable of detecting current flowing through the bus bar;
In a current detection device comprising
The bus bar has a first bus bar, a second bus bar, and a third bus bar that are formed in a flat plate shape, and the first bus bar, the second bus bar, and the third bus bar are laminated with an insulating member interposed to form a single unit. 1. A current detecting device, comprising: a laminated component; and wherein said current detecting sensor is arranged at a position on the side of said laminated component. The current detection sensor is capable of detecting the intensity of a magnetic field generated by a current shunted from the current flowing through the busbar, and is capable of detecting the current flowing through the busbar based on the intensity of the detected magnetic field. The current detection device according to claim 1, characterized by: At least two of the first busbar, the second busbar, and the third busbar have laterally protruding sub-busbars formed on the side surfaces of the busbars, and the current detection sensor can detect a current that is divided and flows through the sub-busbars. 3. The current detection device according to claim 2, wherein: 4. The current detection device according to claim 3, wherein the current detection sensor is attached to a printed circuit board on which an electric circuit is printed, and the printed circuit board is attached to a side surface of the laminated component. The sub-bus bar is composed of two projecting portions projecting apart from each other by a predetermined distance in the extending direction of the bus bar. 5. The current detecting device according to claim 4, wherein the electric current flows through a predetermined electric circuit formed on the printed circuit board and reaches the other projection. 6. The current detecting device according to claim 2, wherein the bus bar in which the sub bus bar is formed is formed with a slit for shunting the current to the sub bus bar. The first bus bar, the second bus bar, and the third bus bar are laminated in three layers of an upper layer, a lower layer, and an intermediate layer, and the current detection sensor is positioned to the side of the intermediate bus bar. The current detection device according to any one of claims 1 to 6.

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