JP7465169B2 - Current Sensor - Google Patents

Description

The present invention relates to a current sensor.

Patent Document 1 describes a current sensor in which a detection element is arranged for each of the three bus bars that transmit three-phase AC power in order to detect the output current of each phase in a three-phase AC motor. When detecting a magnetic field generated due to a current flowing through one bus bar that is the detection target, each detection element is affected by a magnetic field caused by currents flowing through the other two bus bars that are not the detection target. Patent Document 1 devises a bus bar shape and a detection element arrangement to reduce the influence of the magnetic field caused by currents flowing through the bus bars that are not the detection target and to improve the signal-to-noise ratio of each detection element.

JP 2015-132499 A

As in Patent Document 1, a technique is known in which one detection element is provided for each conductor in order to separately detect the currents flowing through multiple conductors, such as bus bars in a three-phase AC motor. However, no technique is known for collectively detecting the currents flowing through multiple conductors using a single detection element, and in this case, a completely different technical concept is required than when the currents flowing through multiple conductors are detected separately using multiple detection elements.

The detection element detects the current by sensing the magnetic flux generated by the current flowing through the conductor. When multiple detection elements are used to detect the currents flowing through multiple conductors separately, the conductors and detection elements are arranged in a one-to-one relationship, so it is relatively easy to appropriately adjust the correspondence between the current flowing through the conductors and the magnetic flux sensed by the detection elements.

In contrast, when currents flowing through multiple conductors are detected collectively by a single detection element, the correspondence between the currents flowing through each conductor and the magnetic flux sensed by the detection element may differ depending on the relative positions of each conductor and the detection element. For example, because magnetic flux density is inversely proportional to the square of the distance between the conductor and the detection element, even if the same amount of current flows through multiple conductors, the magnetic flux density of the magnetic flux generated in a conductor close to the detection element will be higher than the magnetic flux density of the magnetic flux generated in a conductor far from the detection element. As a result, even if the same amount of current flows through multiple conductors, the current value detected in the conductor close to the detection element will be higher than the current value detected in the conductor far from the detection element.

In view of the above, the present invention aims to provide a current sensor that can detect currents flowing through multiple conductors simultaneously with high accuracy using a single detection element.

The current sensor according to the present invention comprises a plurality of conductors, one end of which is conductively connected to a drive circuit and the other end of which is conductively connected to a rotating electric machine, and a detection element that senses the conductor magnetic flux generated by the conductor current flowing through each of the plurality of conductors and detects the currents flowing through the plurality of conductors collectively. The current sensor has a magnetic flux correction mechanism that corrects the conductor magnetic flux for at least one of the plurality of conductors based on the positional relationship between the detection element and each of the plurality of conductors so that the correspondence between the conductor current and the conductor magnetic flux sensed by the detection element is approximately equivalent in each of the plurality of conductors.

According to the current sensor of the present invention, the detection element detects the conductor magnetic flux generated by the conductor current flowing through each of the multiple conductors, and detects the currents flowing through the multiple conductors collectively. The magnetic flux correction mechanism is designed to correct the conductor magnetic flux based on the positional relationship between the detection element and each of the multiple conductors so that the correspondence between the conductor current and the conductor magnetic flux detected by the detection element is approximately equivalent. This makes it possible to alleviate the difference in the correspondence between the current flowing through each conductor and the magnetic flux detected by the detection element, which is caused by the positional relationship between each conductor and the detection element. As a result, it is possible to provide a current sensor that detects the currents flowing through multiple conductors collectively with high accuracy using a single detection element.

A driving device for a rotating electric machine including a driving circuit to which the current sensor according to the first embodiment is applied. FIG. 2 is a diagram showing a current sensor according to the first embodiment. FIG. 13 is a diagram showing a current sensor according to a modified example. FIG. 13 is a diagram showing a current sensor according to a second embodiment. FIG. 13 is a diagram showing a current sensor according to a third embodiment. FIG. 13 is a diagram showing a current sensor according to a modified example. FIG. 13 is a diagram showing a current sensor according to a fourth embodiment. FIG. 13 is a diagram showing a current sensor according to a fifth embodiment. FIG. 13 is a diagram showing a current sensor according to a sixth embodiment. FIG. 13 is a diagram showing a current sensor according to a seventh embodiment. FIG. 13 is a diagram showing a current sensor according to an eighth embodiment. FIG. 13 is a diagram showing a current sensor according to a modified example. FIG. 13 is a diagram showing a current sensor according to a ninth embodiment. FIG. 13 is a diagram showing a current sensor according to a modified example. FIG. 13 is a diagram showing a current sensor according to a modified example.

First Embodiment
The detection element of the first embodiment is a sensor for collectively detecting the currents flowing through the U phase, V phase, and W phase of a rotating electric machine, which is a three-phase AC motor, and can be used, for example, as a monitoring sensor DT in a drive device 10 for a rotating electric machine as shown in Figure 1.

Figure 1 shows a drive device 10 that controls the drive of a rotating electric machine. The rotating electric machine is a three-phase open winding with an open neutral point, and includes a U-phase winding U, a V-phase winding V, and a W-phase winding W. The drive device 10 includes a drive circuit 11, a control unit 12, and a DC power supply VDC. The drive circuit 11 includes a first inverter INV1, a second inverter INV2, a high potential connection line La, a low potential connection line Lb, a connection line switch SC, phase current sensors DU, DV, and DW, and a monitoring sensor DT.

The first inverter INV1 is a three-phase inverter connected to a DC power source VDC, and includes an upper arm switch SU1a and a lower arm switch SU1b connected to one end of the U-phase winding U of the rotating electric machine, an upper arm switch SV1a and a lower arm switch SV1b connected to one end of the V-phase winding V, and an upper arm switch SW1a and a lower arm switch SW1b connected to one end of the W-phase winding W.

The second inverter INV2 is a three-phase inverter and includes an upper arm switch SU2a and a lower arm switch SU2b connected to the other end of the U-phase winding U of the rotating electric machine, an upper arm switch SV2a and a lower arm switch SV2b connected to the other end of the V-phase winding V, and an upper arm switch SW2a and a lower arm switch SW2b connected to the other end of the W-phase winding W.

The high potential connection line La is a wiring that connects the high DC potential side of the first inverter INV1 to the high DC potential side of the second inverter INV2. The low potential connection line Lb connects the low DC potential side of the first inverter INV1 to the low DC potential side of the second inverter.

In the first inverter INV1, the high-potential terminals of the upper arm switches SU1a, SV1a, and SW1a of each phase are connected to the positive terminal of the DC power supply VDC, and the low-potential terminals of the lower arm switches SU1b, SV1b, and SW1b of each phase are connected to the negative terminal of the DC power supply VDC. The upper arm switches SU1a, SV1a, and SW1a and the lower arm switches SU1b, SV1b, and SW1b are each a semiconductor switching element.

In the second inverter INV2, the high-potential terminals of the upper arm switches SU2a, SV2a, and SW2a of each phase are connected to the high-potential connection line La, and the low-potential terminals of the lower arm switches SU2b, SV2b, and SW2b of each phase are connected to the low-potential connection line Lb. The upper arm switches SU2a, SV2a, and SW2a and the lower arm switches SU2b, SV2b, and SW2b are each a semiconductor switching element. Examples of semiconductor switching elements include MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) and IGBTs (Insulated Gate Bipolar Transistors) having a freewheel diode connected in inverse parallel.

In the first inverter INV1, the midpoints between the upper arm switches SU1a, SV1a, SW1a and the lower arm switches SU1b, SV1b, SW1b of each phase are connected to one end of the windings U, V, W (one end not connected to the second inverter INV2) by the first phase connection lines LU1, LV1, LW1. In the second inverter INV2, the midpoints between the upper arm switches SU2a, SV2a, SW2a and the lower arm switches SU2b, SV2b, SW2b of each phase are connected to one end of the windings U, V, W (one end not connected to the first inverter INV1) by the second phase connection lines LU2, LV2, LW2. One current sensor is installed on each of the first phase connection lines LU1, LV1, LW1 as phase current sensors DU, DV, DW. In addition, a monitoring sensor DT is installed as a single current sensor that can simultaneously detect all currents flowing through the three first-phase connection lines LU1, LV1, and LW1.

The connection line switch SC is provided on the high potential connection line La, and connects or disconnects the first inverter INV1 and the second inverter INV2 by connecting or disconnecting the high potential connection line La. When the connection line switch SC is in a closed state (on state), the drive circuit 11 can be used as an H-bridge circuit, enabling H-drive of the rotating electric machine.

When the connection line switch SC is in an open state (off state), the drive circuit 11 enables Y-drive of the rotating electric machine. For example, by closing all the upper arm switches SU2a, SV2a, SW2a of the second inverter INV2 and opening all the lower arm switches SU2b, SV2b, SW2b, the rotating electric machine can be Y-driven. That is, the U-phase winding U, the V-phase winding V, and the W-phase winding W of the rotating electric machine can be connected by a Y-connection. In this case, the upper arm switches SU2a, SV2a, SW2a correspond to the neutral point configuration switches that configure the neutral point of the Y-connection (star connection).

The control unit 12 is equipped with a microcomputer consisting of a CPU and various memories, and performs current control by opening and closing (on/off) each switch in the first inverter INV1 and the second inverter INV2 based on various detection information from the rotating electric machine and requests for power running and power generation. Detection information from the rotating electric machine includes, for example, the rotation angle (electrical angle information) of the rotor detected by an angle detector such as a resolver, the power supply voltage (inverter input voltage) detected by a voltage sensor, and the current flowing through each phase detected by a current sensor.

The control unit 12 further controls the opening and closing of the connection line switch SC. During H drive, the control unit 12 controls the connection line switch SC to a closed state, and during Y drive, the control unit 12 controls the connection line switch SC to an open state. The control unit 12 generates and outputs operation signals that operate each switch of the first inverter INV1 and the second inverter INV2 and the connection line switch SC.

When driving the rotating electric machine in H mode, the control unit 12 can control the connection line switch SC to a closed state, for example, to perform alternating PWM driving. Alternating PWM driving is an example of asymmetric switching control that alternately operates the first inverter INV1 and the second inverter INV2.

When the rotating electric machine is Y-driven, the control unit 12 controls the connection line switch SC to an open state, controls the upper arm switches SU2a, SV2a, and SW2a of the second inverter INV2 to a closed state, and controls the lower arm switches SU2b, SV2b, and SW2b of the second inverter INV2 to an open state, so that the U-phase winding U, the V-phase winding V, and the W-phase winding W of the rotating electric machine are Y-connected. More specifically, the winding terminals of the windings U, V, and W on the second inverter INV2 side are connected via the upper arm switches SU2a, SV2a, and SW2a, respectively, to realize the Y-connection. The Y-connection is configured using the second inverter INV2, and the first inverter INV1 is subjected to PWM control or the like, so that the rotating electric machine can be Y-driven. The upper arm switches SU2a, SV2a, and SW2a correspond to neutral point configuration switches that configure the neutral point of the Y-connection. The lower arm switches SU2b, SV2b, and SW2b do not constitute a neutral point and are therefore equivalent to non-neutral point configuration switches.

During H drive of the rotating electric machine, the control unit 12 acquires the phase currents IU, IV, IW detected by the phase current sensors DU, DV, DW and the total current IT detected by the monitoring sensor DT, and performs fault diagnosis of the drive circuit 11 based on the phase currents IU, IV, IW and the total current IT. More specifically, the control unit 12 calculates the total current IS (three-phase sum calculation value) of the phase currents IU, IV, IW, and compares the current waveform with the current waveform of the total current IT, which is the detection value of the monitoring sensor DT. During H drive of the rotating electric machine, the phase currents IU, IV, IW of the U, V, and W phases detected by the phase current sensors DU, DV, and DW are not in phase with each other, so they do not cancel each other out. As a result, the total current IS of the third-order component does not become zero, and has a sine waveform under normal conditions. In addition, the control unit 12 can obtain the total current IS by acquiring the phase currents IU, IV, and IW from the phase current sensors DU, DV, and DW and calculating the sum of the third-order components.

For example, if both the sum current IS and the total current IT have abnormal waveforms (are not normal sine waveforms), the control unit 12 determines that this corresponds to a failure mode such as an element failure (for example, failure of a switching element that constitutes each inverter INV1, INV2), and that the failure is not in the phase current sensors DU, DV, DW or the monitoring sensor DT, but in another part of the drive circuit 11.

In addition, when the total current IS has an abnormal waveform and the total current IT has a normal waveform, the control unit 12 determines that the failure mode corresponds to a phase current sensor failure, and that at least one of the phase current sensors DU, DV, and DW has failed.

In addition, if the total current IS has a normal waveform and the total current IT has an abnormal waveform, the control unit 12 determines that the failure mode corresponds to a monitoring sensor failure and that the monitoring sensor DT has failed.

In addition, if both the sum current IS and the total current IT have normal sine waveforms, the control unit 12 determines that all of the phase current sensors DU, DV, DW and the monitoring sensor DT are normal.

Figure 2 shows the current sensor 100 according to the first embodiment. The current sensor 100 comprises a detection element 101, multiple magnetic bodies 102a-102c, multiple conductors 103-105, a circuit board 106, and a casing 107. Note that Figure 2(a) is a cross-sectional view of the current sensor 100, and Figure 2(b) is a plan view of the conductors 103-105 of the current sensor 100, showing the positional relationship in the planar direction between the conductors 103-105, the detection element 101, and the magnetic bodies 102a and 102b.

The multiple conductors 103 to 105 are so-called bus bars, one end of which is conductively connected to a drive circuit and the other end of which is conductively connected to a rotating electric machine. More specifically, conductor 103 is conductively connected to the U-phase of the rotating electric machine, conductor 104 is conductively connected to the V-phase, and conductor 105 is conductively connected to the W-phase. The conductors 103 to 105 are flat plates with the xy plane as their planar direction, and are approximately the same in shape and size. A portion of the conductors 103 to 105 is housed within the casing 107.

Detection element 101 is mounted on the upper surface of circuit board 106 (the surface on the positive side of the z-axis shown in FIG. 2). Magnetic bodies 102a and 102b are mounted on the upper surface of circuit board 106 at positions that are respectively in the negative and positive directions of the x-axis relative to detection element 101. Detection element 101, magnetic bodies 102a to 102c, and circuit board 106 are entirely housed within casing 107.

The three conductors 103 to 105 are positioned in the negative direction of the z-axis relative to the detection element 101, and are shifted in the x-axis direction. Conductor 104 is positioned directly below the detection element 101, and conductors 103 and 105 are positioned in positions shifted in the negative and positive directions of the x-axis from directly below the detection element 101. Conductor 103 is positioned directly below magnetic body 102a, and conductor 105 is positioned directly below magnetic body 102b. Magnetic body 102c is positioned directly below conductor 104.

Here, if the z-axis direction perpendicular to the top and bottom surfaces of the detection element 101 is defined as the first direction, and the x-axis direction perpendicular to the first direction is defined as the second direction, then the conductors 103-105 can be said to be arranged offset from one another in the second direction at a position that corresponds to the first direction of the detection element 101. The y-axis direction perpendicular to the first and second directions is the direction of current flow through the conductors 103-105. The magnetic bodies 102a and 102b correspond to the sensor-side magnetic bodies arranged in the second direction of the detection element 101, and the magnetic body 102c corresponds to the sensor-opposing magnetic body arranged in a position that faces the detection element 101 via the conductors 103-105.

The conductor 103 is a U-phase current of the rotating electric machine that flows in the positive direction of the y-axis as a conductor current. The conductor 104 is a V-phase current of the rotating electric machine that flows in the positive direction of the y-axis as a conductor current. The conductor 105 is a W-phase current of the rotating electric machine that flows in the positive direction of the y-axis as a conductor current. The detection element 101 is a coreless current element that detects the conductor current by detecting the magnetic flux generated by the conductor current. The detection element 101 detects the U-phase magnetic flux generated by the U-phase current, the V-phase magnetic flux generated by the V-phase current, and the W-phase magnetic flux generated by the W-phase current, and detects the U-phase current, V-phase current, and W-phase current collectively. The U-phase current, V-phase current, and W-phase current that flow in the positive direction of the y-axis generate magnetic fluxes M1 and M2 in the positive direction of the x-axis in the detection element 101. The detection element 101 detects the magnetic fluxes M1 and M2 and outputs a voltage value according to the magnetic fluxes M1 and M2 to the circuit board 106.

The magnetic bodies 102a to 102c are made of a magnetic material whose magnetic permeability can be adjusted. The magnetic bodies 102a to 102c form a closed circuit with low magnetic resistance to adjust the magnetic flux density and direction of the U-phase magnetic flux and the W-phase magnetic flux. For example, since the magnetic flux density is inversely proportional to the square of the distance between the conductors 103 to 105 and the detection element 101, if the magnetic bodies 102a to 102c do not exist, even if the same amount of current flows through the conductors 103 to 105, the magnetic flux density of the magnetic flux M1 generated in the conductor close to the detection element 101 will be higher than the magnetic flux density of the magnetic flux M2 generated in the conductors 103 and 105 far from the detection element 101. As shown in FIG. 2(a), by providing magnetic bodies 102a-102c, a closed circuit with low magnetic resistance is formed, and the correspondence between the V-phase current flowing through conductor 104 and magnetic flux M1 can be made approximately equivalent to the correspondence between the U-phase current and W-phase current flowing through conductors 103 and 105, respectively, and magnetic flux M2.

As described above, the current sensor 100 includes three conductors 103-105, one end of which is conductively connected to a drive circuit and the other end of which is conductively connected to a rotating electric machine, and a detection element 101 that detects the conductor magnetic flux generated by the conductor current flowing through each of the conductors 103-105 and detects the current flowing through the three conductors 103-105 collectively. The current sensor 100 further includes magnetic bodies 102a-102c. The arrangement of the magnetic bodies 102a-102c functions as a magnetic flux correction mechanism that corrects the conductor magnetic flux for at least one of the three conductors so that the correspondence between the conductor current and the conductor magnetic flux detected by the detection element 101 is approximately equivalent in each of the three conductors based on the positional relationship between the detection element 101 and each of the three conductors 103-105. This can mitigate the difference in the correspondence between the current flowing through each conductor 103-105 and the magnetic flux sensed by the detection element 101, which is caused by the positional relationship between each conductor 103-105 and the detection element 101. As a result, the current sensor 100 can detect the current flowing through the conductors 103-105 collectively with high accuracy using a single detection element 101.

When the conductors 103-105 are arranged offset from one another in the second direction in a position that is the first direction of the detection element 101, as in the current sensor 100, the magnetic bodies are arranged to include the sensor-side magnetic bodies 102a and 102b arranged in the second direction of the detection element 101, and the sensor-opposing magnetic body 102c arranged in a position that faces the detection element 101 across the conductors 103-105, as shown in FIG. 2. This makes it possible to mitigate the difference in the correspondence between the current flowing through each conductor 103-105 and the magnetic flux sensed by the detection element 101, and allows the current flowing through the conductors 103-105 to be detected collectively with high accuracy by the single detection element 101.

(Modification)
Fig. 3 shows a current sensor 110 according to a modified example. The current sensor 110 includes a detection element 111, a plurality of magnetic bodies 112a-112c, a plurality of conductors 113-115, a circuit board 116, and a casing 117. The conductors 113-115 differ from the conductors 103-105 shown in Fig. 2 in that they are flat plates with the yz plane as their planar direction. The rest of the configuration is the same as that of the current sensor 100, and therefore the components shown in Fig. 3 will be omitted from description by replacing the components shown in Fig. 2 with the 100-series components with the 110-series components.

If the z-axis direction perpendicular to the top and bottom surfaces of the detection element 111 is defined as the first direction, and the x-axis direction perpendicular to the first direction is defined as the second direction, then the conductors 113-115 can be said to be arranged offset from each other in the second direction in a position that corresponds to the first direction of the detection element 111. The y-axis direction perpendicular to the first and second directions is the direction of current flow through the conductors 113-115. The magnetic bodies 112a and 112b correspond to the sensor-side magnetic bodies arranged in the second direction of the detection element 111, and the magnetic body 112c corresponds to the sensor-opposing magnetic body arranged in a position that faces the detection element 111 via the conductors 113-115.

Detection element 111 senses the U-phase magnetic flux generated by the U-phase current, the V-phase magnetic flux generated by the V-phase current, and the W-phase magnetic flux generated by the W-phase current, and detects the U-phase current, V-phase current, and W-phase current collectively. Detection element 111 senses magnetic fluxes M11 and M12 in the positive direction of the x-axis.

As with the current sensor 100, in the current sensor 110, the conductors 113-115 are arranged in a position that is the first direction of the detection element 111, offset from each other in the second direction. In this case, as with the current sensor 100, the magnetic bodies are arranged to include the sensor-side magnetic bodies 112a and 112b arranged in the second direction of the detection element 111, and the sensor-opposing magnetic body 112c arranged in a position that faces the detection element 111 across the conductors 113-115, thereby mitigating the difference in the correspondence between the current flowing through each conductor 113-115 and the magnetic fluxes M11 and M12 sensed by the detection element 111. The currents flowing through the conductors 113-115 can be detected collectively with high accuracy by the single detection element 111.

Second Embodiment
4 shows a current sensor 120 according to the second embodiment. The current sensor 120 includes a detection element 121, a plurality of magnetic bodies 122a and 122b, a plurality of conductors 123 to 125, a circuit board 126, and a casing 127. The current sensor 120 differs from the current sensor 100 in that the conductors 123 to 125 are shifted in the z-axis direction at a position in the negative direction of the z-axis relative to the detection element 121, and that the magnetic bodies 122a and 122b are arranged in a second direction relative to the conductors 123 to 125. The other configurations are the same as those of the current sensor 100, so that the configurations shown in FIG. 4 will not be described by replacing the configurations shown in FIG. 2 with the 120s.

The three conductors 123 to 125 are arranged in a position that is in the negative direction of the z-axis relative to the detection element 121, and are shifted in the z-axis direction. The conductors 123 to 125 are arranged directly below the detection element 121 in the order of conductor 123, conductor 124, and conductor 125, from the side closer to the detection element 121 to the side farther away. The magnetic bodies 122a and 122b are arranged in positions that are in the negative and positive directions of the x-axis relative to the conductors 124 and 125, respectively.

The conductors 123 to 125 can be said to be arranged offset from one another in the first direction, at positions that correspond to the first direction of the detection element 121. The y-axis direction perpendicular to the first and second directions is the direction of current flow through the conductors 123 to 125. The magnetic bodies 122a and 122b correspond to conductor-lateral magnetic bodies arranged in positions that correspond to the second direction relative to the conductors 123 to 125.

Detection element 121 senses the U-phase magnetic flux generated by the U-phase current, the V-phase magnetic flux generated by the V-phase current, and the W-phase magnetic flux generated by the W-phase current, and detects the U-phase current, V-phase current, and W-phase current collectively. Detection element 121 senses magnetic fluxes M21 and M22 in the positive direction of the x-axis.

As described above, the current sensor 120 includes three conductors 123-125, one end of which is conductively connected to a drive circuit and the other end of which is conductively connected to a rotating electric machine, and a detection element 121 that detects the conductor magnetic flux generated by the conductor current flowing through each of the conductors 123-125 and collectively detects the current flowing through the three conductors 123-125. The current sensor 120 further includes magnetic bodies 122a and 122b. The magnetic bodies 122a and 122b function as a magnetic flux correction mechanism that corrects the conductor magnetic flux for at least one of the three conductors based on the positional relationship between the detection element 121 and each of the three conductors 123 so that the correspondence between the conductor current and the conductor magnetic flux detected by the detection element 121 is approximately equivalent in each of the three conductors. This can mitigate the difference in the correspondence between the current flowing through each conductor 123-125 and the magnetic flux sensed by the detection element 121, which is caused by the positional relationship between each conductor 123-125 and the detection element 121. As a result, the current sensor 120 can detect the current flowing through the conductors 123-125 collectively with high accuracy using a single detection element 121.

When the conductors 123-125 are arranged offset from one another in the first direction in a position that corresponds to the first direction of the detection element 121, as in the current sensor 120, the magnetic bodies are arranged to include conductor lateral magnetic bodies 122a and 122b arranged in a position that corresponds to the second direction relative to the conductors 123-125, as shown in FIG. 4. This makes it possible to mitigate the difference in the correspondence between the current flowing through each conductor 123-125 and the magnetic flux sensed by the detection element 121, and the current flowing through the conductors 123-125 can be detected collectively with high accuracy by the single detection element 121.

In each of the above embodiments, the current sensors 100, 110, and 120 are described as including an arrangement of magnetic bodies designed based on the positional relationship between the detection element and each of the three conductors as a magnetic flux correction mechanism. However, in order to function as a magnetic flux correction mechanism, the arrangement of each magnetic body needs to be designed based on the positional relationship between the detection element and each of the three conductors, and it is sufficient that the magnetic body corrects at least one of the magnetic flux density and the magnetic flux direction for the conductor magnetic flux of at least one of the three conductors.

Third Embodiment
5 shows a current sensor 130 according to a third embodiment. The current sensor 130 includes a detection element 131, a plurality of conductors 133 to 135, a circuit board 136, and a casing 137. The current sensor 130 differs from the current sensor 100 in that the shapes and sizes of the conductors 133 to 135 are not substantially the same, and in that the current sensor 130 does not include a magnetic material. As the other configurations are the same as those of the current sensor 100, the components shown in FIG. 2 with numbers in the 100 range will be replaced with numbers in the 130 range, and a description of the components shown in FIG. 5 will be omitted.

The three conductors 133 to 135 are arranged at positions in the negative direction of the z-axis relative to the detection element 131, with a shift in the x-axis direction. The conductor 134 is arranged directly below the detection element 131, and the conductors 133 and 135 are arranged at positions shifted in the negative and positive directions of the x-axis from directly below the detection element 101. The conductors 133 to 135 are arranged at positions in the first direction of the detection element 131, with a shift in the second direction from each other. The y-axis direction, which is perpendicular to the first and second directions, is the direction in which current flows through the conductors 133 to 135.

As shown in FIG. 3(b), the conductor 133 is generally U-shaped with a notch in the negative x-axis direction, and has both ends 133a and 133c in the y-axis direction, and a central portion 133b located between both ends 133a and 133c in the y-axis direction. The width of the central portion 133b in the x-axis direction is narrower than the width of both ends 133a and 133c in the x-axis direction.

The conductor 134 is generally I-shaped with notches in the negative and positive directions of the x-axis, and has both ends 134a and 134c in the y-axis direction, and a central portion 134b located between both ends 134a and 134c in the y-axis direction. The width of the central portion 134b in the x-axis direction is narrower than the width of both ends 134a and 134c in the x-axis direction.

The conductor 135 is generally U-shaped with a notch in the positive x-axis direction, and has both ends 135a and 135c in the y-axis direction, and a central portion 135b located between both ends 135a and 135c in the y-axis direction. The width of the central portion 135b in the x-axis direction is narrower than the width of both ends 135a and 135c in the x-axis direction. As shown in conductors 133 to 135, it is preferable to provide the notch on the side farther from the detection element 131.

The width in the x-axis direction of the central portion 134b of the conductor 134 is wider than the width in the x-axis direction of the central portions 133b and 135b of the conductors 133 and 135. Since the conductors 133 to 135 have the same thickness in the z-axis direction, the cross-sectional area in the flow direction of the V-phase current in the central portion 134b of the conductor 134 is wider than the cross-sectional areas in the flow directions of the U-phase current and W-phase current in the central portions 133b and 135b of the conductors 133 and 135.

That is, the width in the second direction (x-axis direction) of the central portions 133b, 134b, and 135b of the conductors 133 to 135 is narrower than the width in the second direction (x-axis direction) of both ends 133a, 133c, 134a, 134c, 135a, and 135c in the direction of conductor current flow (y-axis direction). In addition, the conductor 134 corresponds to a near-horizontal conductor that is closer to the detection element 131 in the second direction, and the conductors 133 and 135 correspond to far-horizontal conductors that are farther from the detection element 131 in the second direction than the near-horizontal conductors. The central portion 134b of the conductor 134 that corresponds to the near-horizontal conductor is wider in the second direction than the central portions 133b and 135b of the conductors 133 and 135 that correspond to the far-horizontal conductors, and therefore has a larger cross-sectional area in the direction of conductor current flow.

Detection element 131 detects U-phase magnetic flux generated by U-phase current, V-phase magnetic flux generated by V-phase current, and W-phase magnetic flux generated by W-phase current, and detects U-phase current, V-phase current, and W-phase current collectively. Detection element 131 detects magnetic fluxes M31 and M32 in the positive direction of the x-axis. As shown in FIG. 5(b), the shape of conductors 133-135 is designed based on the positional relationship between detection element 131 and each of the three conductors 133-135, and the cross-sectional area in the flow direction of U-phase current, V-phase current, and W-phase current is adjusted, so that the correspondence between the V-phase current flowing in conductor 134 and magnetic flux M31 and the correspondence between the U-phase current and W-phase current flowing in conductors 133 and 135, respectively, and magnetic flux M32 can be made approximately equivalent.

Since magnetic flux density is inversely proportional to the square of the distance between conductors 133-135 and detection element 131, it is preferable to design the cross-sectional area in the direction of the flow of the conductor current so as to cancel out the difference in magnetic flux density due to this difference in distance. For example, if the distance between detection element 131 and conductor 134 is taken as the reference distance and the distance between detection element 131 and conductor 133 is Ru times, and the distance between detection element 131 and conductor 135 is Rw times, then the flow path cross-sectional area Su of the U-phase current can be calculated as Su x Ru^2 = Sv, and the flow path cross-sectional area Sw of the W-phase current can be calculated as Sw x Rw^2 = Sv. Note that Ru^2 is the square of Ru, and Rw^2 is the square of Rw.

As described above, the current sensor 130 includes three conductors 133-135, one end of which is conductively connected to a drive circuit and the other end of which is conductively connected to a rotating electric machine, and a detection element 131 that detects the conductor magnetic flux generated by the conductor current flowing through each of the conductors 133-135 and detects the current flowing through the three conductors 133-135 collectively. In the current sensor 130, the shape and size of each of the three conductors 133-135 are designed based on the positional relationship between the detection element 131 and each of the three conductors 133-135. The combination of the three conductors 133-135 designed in this way functions as a magnetic flux correction mechanism that corrects the conductor magnetic flux for at least one of the three conductors so that the corresponding relationship between the conductor current and the conductor magnetic flux detected by the detection element 131 is approximately equivalent. This can mitigate the difference in the correspondence between the current flowing through each conductor 133-135 and the magnetic flux sensed by the detection element 131, which is caused by the positional relationship between each conductor 133-135 and the detection element 131. As a result, the current sensor 130 can detect the current flowing through the conductors 133-135 collectively with high accuracy using a single detection element 131.

When the conductors 133-135 are arranged offset from each other in the second direction at a position that corresponds to the first direction of the detection element 131, as in the current sensor 130, a combination of the conductors 133-135 designed as shown in FIG. 5 can be adopted. This allows the cross-sectional area in the flow direction of the V-phase current flowing through the conductor 134 close to the detection element 131 to be wider than the cross-sectional area in the flow direction of the U-phase current and W-phase current flowing through the conductors 133 and 135 far from the detection element 131. As a result, it is possible to mitigate the difference in the correspondence between the current flowing through each conductor 133-135 and the magnetic flux sensed by the detection element 131, and the current flowing through the conductors 133-135 can be detected collectively with high accuracy by a single detection element 131.

(Modification)
6, the technology according to the third embodiment can also be applied to a case where the conductor 144 is disposed below the conductors 143 and 145 and a part of the conductor 144 overlaps with a part of the conductors 143 and 145 when viewed in the z-axis direction. That is, the conductor 144 is made substantially I-shaped like the conductor 134, the conductors 143 and 145 are made substantially U-shaped, and the cross-sectional areas in the flow direction of the U-phase current, the V-phase current, and the W-phase current are adjusted based on the square of the distance between the detection element 131 and each of the conductors 133 to 135, thereby making the correspondence relationship between the V-phase current flowing in the conductor 144 and the magnetic flux substantially equivalent to the correspondence relationship between the U-phase current and the W-phase current flowing in the conductors 143 and 145 and the magnetic flux.

Fourth Embodiment
7 shows a current sensor 150 according to a fourth embodiment. The current sensor 150 includes a detection element 151, a plurality of conductors 153 to 155, a circuit board 156, and a casing 157. The current sensor 150 differs from the current sensor 130 in that the conductors 153 to 155 are arranged at positions in the negative direction of the z-axis with respect to the detection element 151, and that the conductors 153 to 155 are different from each other. As the other configurations are the same as those of the current sensor 130, the components numbered in the 130s in FIG. 5 are replaced with components numbered in the 150s, and the description of the components shown in FIG. 7 is omitted.

The three conductors 153 to 155 are arranged in a position that is in the negative direction of the z axis with respect to the detection element 151, and are shifted in the z axis direction. The conductors 153 to 155 are arranged directly below the detection element 151 in the order of conductor 153, conductor 154, and conductor 155, from the side closer to the detection element 151 to the side farther away. It can be said that the conductors 153 to 155 are arranged in a position that is in the first direction of the detection element 151, and are shifted from each other in the first direction. The y axis direction, which is perpendicular to the first and second directions, is the direction in which electricity flows through the conductors 153 to 155.

Similar to conductor 134, conductors 153 to 155 are roughly I-shaped with notches in the negative and positive x-directions. The widths in the x-direction of central portions 153b, 154b, and 155b are narrower than the widths in the x-direction of both ends 153a, 153c, 154a, 154c, 155a, and 155c. The widths in the x-direction of the central portions increase in the order of central portion 155b, central portion 154b, and central portion 153b.

That is, the conductors 153 to 155 correspond to a combination of multiple conductors arranged at a position that is the first direction of the detection element 151, and are shifted from each other in the first direction. The width of the center portions 153b, 154b, and 155b of the conductors 153 to 155 in the second direction is narrower than the width of the ends 153a, 153c, 154a, 154c, 155a, and 155c in the second direction in the direction of the conductor current flow. The conductor 153 corresponds to a near-vertical conductor that is closer to the detection element 151 in the first direction, and the conductors 154 and 155 correspond to far-vertical conductors that are farther from the detection element 151 in the first direction than the near-vertical conductor. The center portion 153b of the conductor 153 that corresponds to the near-vertical conductor has a wider width in the second direction than the center portions 154b and 155b of the conductors 154 and 155 that correspond to the far-vertical conductors, and therefore has a larger cross-sectional area in the direction of the conductor current flow.

As in the third embodiment, the width in the x-axis direction of central portions 153b, 154b, and 155b can be designed based on the square of the distance between conductors 153-155 and detection element 151. For example, if the distance between detection element 151 and conductor 153 is taken as a reference, and the distance between detection element 151 and conductor 154 is Rv times, and the distance between detection element 151 and conductor 155 is Rw times, then the flow path cross-sectional area Sv of the V-phase current can be calculated as Sv x Rv^2 = Su, and the flow path cross-sectional area Sw of the W-phase current can be calculated as Sw x Rw^2 = Su.

As described above, the combination of the three conductors 153 to 155 in the current sensor 150 functions as a magnetic flux correction mechanism that corrects the conductor magnetic flux for at least one of the three conductors so that the correspondence between the conductor current and the conductor magnetic flux sensed by the detection element 151 is approximately equivalent. Therefore, the current flowing through the conductors 153 to 155 can be detected collectively with high accuracy by the single detection element 151.

When the conductors 153-155 are arranged offset from each other in the first direction at a position that corresponds to the first direction of the detection element 151, as in the current sensor 150, a combination of the conductors 153-155 designed as shown in FIG. 5 can be adopted. This allows the cross-sectional area in the flow direction of the U-phase current flowing in the conductor 153 close to the detection element 151 to be wider than the cross-sectional areas in the flow direction of the V-phase current and W-phase current flowing in the conductors 154 and 155 far from the detection element 151. As a result, it is possible to mitigate the difference in the correspondence between the current flowing in each conductor 153-155 and the magnetic flux sensed by the detection element 151, and the current flowing in the conductors 153-155 can be detected collectively with high accuracy by a single detection element 151.

Fifth Embodiment
Fig. 8 shows a current sensor 160 according to a fifth embodiment. The current sensor 160 includes a detection element 161, a plurality of conductors 163 to 165, a circuit board 166, and a casing 167. The current sensor 160 differs from the current sensor 130 shown in Fig. 5 in that the conductors 163 to 165 are flat with the yz plane as the planar direction, and that the conductors 163 to 165 are all substantially U-shaped. The rest of the configuration is the same as that of the current sensor 130, and therefore the components numbered in the 130s in Fig. 5 are replaced with components numbered in the 160s, and the description of the components shown in Fig. 7 will be omitted.

The conductors 163 to 165 are arranged in a first direction (z-axis direction) of the detection element 161, offset from one another in the second direction (x-axis direction). The y-axis direction, which is perpendicular to the first and second directions, is the direction in which electricity flows through the conductors 163 to 165.

The conductors 163 to 165 are generally U-shaped with a notch in the negative z-axis direction. The width in the z-axis direction of the central portions 163b, 164b, and 165b is narrower than the width in the z-axis direction of both ends 163a, 163c, 164a, 164c, 165a, and 165c. The width in the z-axis direction of the central portion 164b is wider than the central portions 163b and 165b. Since the conductors 163 to 165 have the same thickness in the x-axis direction, the cross-sectional area in the direction of the flow of the V-phase current at the central portion 164b of the conductor 164 is wider than the cross-sectional areas in the direction of the flow of the U-phase current and the W-phase current at the central portions 163b and 165b of the conductors 163 and 165.

Detection element 161 senses the U-phase magnetic flux generated by the U-phase current, the V-phase magnetic flux generated by the V-phase current, and the W-phase magnetic flux generated by the W-phase current, and detects the U-phase current, V-phase current, and W-phase current collectively. Detection element 161 senses magnetic fluxes M11 and M12 in the positive direction of the x-axis.

As in the third embodiment, by adjusting the cross-sectional areas of the U-phase current, V-phase current, and W-phase current in the flow direction based on the square of the distance between the detection element 161 and each of the conductors 163 to 165, the correspondence between the V-phase current flowing in the conductor 164 and the magnetic flux can be made approximately equivalent to the correspondence between the U-phase current and the W-phase current flowing in the conductors 163 and 165, respectively, and the magnetic flux.

As described above, the conductors 163 to 165 correspond to a combination of multiple conductors arranged at a position in the first direction of the detection element 161, shifted from each other in the second direction. The width of the central portions 163b, 164b, and 165b of the conductors 163 to 165 in the first direction is narrower than the width of the ends 163a, 163c, 164a, 164c, 165a, and 165c in the first direction in the direction of the flow of the conductor current. The conductor 164 corresponds to a near-horizontal conductor that is closer to the detection element 161 in the second direction, and the conductors 163 and 165 correspond to far-horizontal conductors that are farther from the detection element 161 in the second direction than the near-horizontal conductor. The central portion 164b of the conductor 164 corresponding to the near-horizontal conductor has a wider width in the first direction than the central portions 163b and 165b of the conductors 163 and 165 corresponding to the far-horizontal conductors, and therefore has a larger cross-sectional area in the direction of the flow of the conductor current.

When the conductors 163-165 are flat plates with the yz plane as the plane direction, as in the current sensor 160, a combination of conductors 163-165 designed to adjust the central portions 163b, 164b, and 165b by providing a notch in the z-axis direction can be adopted. This allows the cross-sectional area of the V-phase current flowing in the conductor 164 close to the detection element 161 to be wider than the cross-sectional areas of the U-phase current and W-phase current flowing in the conductors 163 and 165 far from the detection element 161. As a result, the difference in the correspondence between the current flowing in each conductor 163-165 and the magnetic flux sensed by the detection element 161 can be mitigated, and the current flowing in the conductors 163-165 can be detected collectively with high accuracy by a single detection element 161.

Sixth Embodiment
Fig. 9 shows a current sensor 170 according to a sixth embodiment. The current sensor 170 includes a detection element 171, a plurality of conductors 173-175, a circuit board 176, and a casing 177. The conductors 173-175 differ from the current sensor 130 shown in Fig. 5 in that the overall width of the conductors 173-175 in the x-axis direction is changed. As the other configurations are the same as those of the current sensor 130, the components numbered in the 130s in Fig. 5 are replaced with components numbered in the 170s, and a description of the components shown in Fig. 9 will be omitted.

As in the third embodiment, the width of the conductors 173 to 175 in the x-axis direction is designed based on the positional relationship between the detection element 171 and each of the three conductors 173 to 175, and the cross-sectional areas of the U-phase current, V-phase current, and W-phase current in the flow direction are adjusted, so that the correspondence between the V-phase current flowing in the conductor 174 and the magnetic flux M71 can be made approximately equivalent to the correspondence between the U-phase current and the W-phase current flowing in the conductors 173 and 175, respectively, and the magnetic flux M72.

Seventh Embodiment
Figure 10 shows a current sensor 180 according to the seventh embodiment. The current sensor 180 includes a detection element 181, a plurality of conductors 183-185, a circuit board 186, and a casing 187. The conductors 183-185 differ from the current sensor 150 shown in Figure 7 in that the overall width of the conductors 183-185 in the x-axis direction is changed. As the other configurations are the same as those of the current sensor 150, the components numbered in the 150s in Figure 7 are replaced with components numbered in the 180s, and a description of the components shown in Figure 10 will be omitted.

As in the fourth embodiment, the width of the conductors 183 to 185 in the x-axis direction is designed based on the positional relationship between the detection element 181 and each of the three conductors 183 to 185, and the cross-sectional areas of the U-phase current, V-phase current, and W-phase current in the flow direction are adjusted, so that the correspondence between the U-phase current flowing in the conductor 183 and the magnetic flux M81 can be made approximately equivalent to the correspondence between the V-phase current and the W-phase current flowing in the conductors 184 and 185, respectively, and the magnetic flux M82.

(Modification)
Fig. 11 shows a current sensor 190 according to a modified example. Current sensor 190 includes a detection element 191, a plurality of conductors 193-195, a circuit board 196, and a casing 197. Conductors 193-195 differ from current sensor 160 shown in Fig. 8 in that the overall width in the z-axis direction is changed. As the other configurations are the same as current sensor 160, the components numbered in the 160s in Fig. 8 are replaced with components numbered in the 190s, and a description of the components shown in Fig. 11 will be omitted.

As in the fifth embodiment, the width of the conductors 193 to 195 in the z-axis direction is designed based on the positional relationship between the detection element 191 and each of the three conductors 193 to 195, and the cross-sectional areas of the U-phase current, V-phase current, and W-phase current in the flow direction are adjusted, so that the relationship between the V-phase current flowing in the conductor 194 and the magnetic flux M can be made approximately equivalent to the relationship between the U-phase current and the W-phase current flowing in the conductors 193 and 195, respectively, and the magnetic flux M.

Eighth embodiment
Fig. 12 shows a current sensor 200 according to an eighth embodiment. The current sensor 200 includes a detection element 201, a plurality of conductors 203-205, a circuit board 206, and a casing 207. The conductors 203-205 differ from the current sensor 170 shown in Fig. 9 in that the overall width is changed in the z-axis direction instead of the x-axis direction. As the other configurations are the same as those of the current sensor 170, the components numbered in the 170s in Fig. 9 are replaced with components numbered in the 200s, and a description of the components shown in Fig. 12 will be omitted.

As in the sixth embodiment, the width of the conductors 203 to 205 in the z-axis direction is designed based on the positional relationship between the detection element 201 and each of the three conductors 203 to 205, and the cross-sectional areas of the U-phase current, V-phase current, and W-phase current in the flow direction are adjusted, so that the relationship between the V-phase current flowing in the conductor 204 and the magnetic flux M can be made approximately equivalent to the relationship between the U-phase current and the W-phase current flowing in the conductors 203 and 205, respectively, and the magnetic flux M.

Ninth embodiment
Fig. 13 shows a current sensor 210 according to the ninth embodiment. The current sensor 210 includes a detection element 211, a plurality of conductors 213-215, a circuit board 216, and a casing 217. The conductors 213-215 differ from the current sensor 180 shown in Fig. 10 in that their widths are changed in the z-axis direction instead of the x-axis direction. As the other configurations are the same as those of the current sensor 180, the components numbered in the 180s in Fig. 10 are replaced with components numbered in the 210s, and a description of the components shown in Fig. 13 will be omitted.

As in the seventh embodiment, the width of the conductors 213 to 215 in the z-axis direction is designed based on the positional relationship between the detection element 211 and each of the three conductors 213 to 215, and the cross-sectional areas of the U-phase current, V-phase current, and W-phase current in the flow direction are adjusted, so that the correspondence between the U-phase current flowing in the conductor 213 and the magnetic flux M111 can be made approximately equivalent to the correspondence between the V-phase current and the W-phase current flowing in the conductors 214 and 215, respectively, and the magnetic flux M112.

(Modification)
Fig. 14 shows a current sensor 220 according to a modified example. The current sensor 220 includes a detection element 221, a plurality of conductors 223-225, a circuit board 226, and a casing 227. The conductors 223-225 are different from the current sensor 200 shown in Fig. 12 in that they are flat plates with the yz plane as the planar direction, and that their width is changed in the x-axis direction instead of the z-axis direction. The rest of the configuration is the same as the current sensor 200, so the components numbered in the 200s in Fig. 12 are replaced with components numbered in the 220s, and the description of the components shown in Fig. 14 is omitted.

As in the eighth embodiment, the width of the conductors 223 to 225 in the x-axis direction is designed based on the positional relationship between the detection element 221 and each of the three conductors 223 to 225, and the cross-sectional areas of the U-phase current, V-phase current, and W-phase current in the flow direction are adjusted, so that the relationship between the V-phase current flowing in the conductor 224 and the magnetic flux M can be made approximately equivalent to the relationship between the U-phase current and the W-phase current flowing in the conductors 223 and 225, respectively, and the magnetic flux M.

(Modification)
Fig. 15 shows a current sensor 230 according to a modified example. The current sensor 230 includes a detection element 231, a plurality of conductors 233-235, a circuit board 236, and a casing 237. The conductors 233-235 differ from the current sensor 200 shown in Fig. 12 in that the shapes of the conductors 233-235 have been changed in the same manner as the current sensor 130 shown in Fig. 5. As the other configurations are the same as those of the current sensor 200, the components numbered in the 200s in Fig. 12 are replaced with components numbered in the 230s, and a description of the components shown in Fig. 14 will be omitted.

The current sensor 230 relates to a technology that applies the technology according to the third embodiment together with the technology according to the eighth embodiment. Based on the positional relationship between the detection element 231 and each of the three conductors 233 to 235, the width in the z-axis direction of the conductors 233 to 235 is designed, and the width in the x-axis direction at the center is designed, so that the cross-sectional areas in the flow direction of the U-phase current, V-phase current, and W-phase current can be adjusted. This makes it possible to make the correspondence between the V-phase current flowing in the conductor 234 and the magnetic flux M approximately equivalent to the correspondence between the U-phase current and the W-phase current flowing in the conductors 233 and 235, respectively, and the magnetic flux M.

In each of the above embodiments, a combination of multiple conductors as a magnetic flux correction mechanism has been described. However, in order to function as a magnetic flux correction mechanism, it is sufficient to correct at least one of the magnetic flux density, the magnetic flux direction, and the distance from the detection element for at least one of the conductor magnetic fluxes of the multiple conductors. Furthermore, the number of multiple conductors is not limited to three, and may be two, four or more.

As shown in the specific example in FIG. 15, the above-described embodiments may be used in combination as appropriate. For example, the magnetic flux correction mechanism may be a current sensor that includes both an arrangement of magnetic bodies and a combination of conductors.

According to each of the above embodiments, the following effects can be obtained.

The current sensor includes a plurality of conductors, a detection element, and a magnetic flux correction mechanism. One end of each of the plurality of conductors is conductively connected to a drive circuit, and the other end is conductively connected to a rotating electric machine. The detection element detects the conductor magnetic flux generated by the conductor current flowing through each of the plurality of conductors, and detects the currents flowing through the plurality of conductors collectively. The magnetic flux correction mechanism corrects the conductor magnetic flux for at least one of the plurality of conductors based on the positional relationship between the detection element and each of the plurality of conductors, so that the correspondence between the conductor current and the conductor magnetic flux sensed by the detection element is approximately equivalent in each of the plurality of conductors. The magnetic flux correction mechanism can alleviate the difference in the correspondence between the current flowing through each conductor and the magnetic flux sensed by the detection element due to the positional relationship between each conductor and the detection element. As a result, a current sensor can be provided that detects the currents flowing through the plurality of conductors collectively with high accuracy using a single detection element.

The magnetic flux compensation mechanism may include an arrangement of magnetic bodies (e.g., an arrangement of magnetic bodies 102a-102c, 112a-112c, 122a, 122b) designed based on the positional relationship between the detection element and each of the multiple conductors. Such an arrangement of magnetic bodies is preferably configured to compensate for at least one of the magnetic flux density and the magnetic flux direction for at least one of the multiple conductors. The arrangement of magnetic bodies forms a closed circuit with low magnetic resistance, and the correspondence between the conductor current flowing through the multiple conductors and the magnetic flux can be made approximately equivalent.

The magnetic flux correction mechanism may include a combination of multiple conductors (e.g., a combination of conductors 133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) designed based on the positional relationship between the detection element and each of the multiple conductors. It is preferable that such a combination of multiple conductors is configured to correct at least one of the magnetic flux density, the direction of the magnetic flux, and the distance from the detection element for at least one of the conductor magnetic fluxes of the multiple conductors. For example, by adjusting the cross-sectional area in the flow direction of the conductor current flowing through the multiple conductors by combining the shapes and sizes of the multiple conductors designed based on the distance between the multiple conductors and the detection element, the correspondence between the conductor current flowing through the multiple conductors and the magnetic flux can be made approximately equivalent.

The control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be realized by one or more dedicated computers configured by combining a processor and a memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by the computer.

100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230...Current sensor, 103-105, 113-115, 123-125, 133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 1 93-195, 203-205, 213-215, 223-225, 233-235...conductor, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231...detection element, 102a-102c, 112a-112c, 122a, 122b...magnetic body

Claims (11)

A plurality of conductors (103-105, 113-115, 123-125, 133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) each having one end conductively connected to a drive circuit and the other end conductively connected to a rotating electric machine;
and a detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) that senses conductor magnetic fluxes generated by conductor currents flowing through the plurality of conductors, and detects the currents flowing through the plurality of conductors collectively;
A magnetic flux correction mechanism (102a to 102c, 112a to 112c, 122a, 122b, 133 to 135, 143 to 145, 153 to 155, 163 to 165, 173 to 175, 183 to 185, 193 to 195, 203 to 205, 213 to 215, 223 to 225, 233 to 235) is provided that corrects a conductor magnetic flux for at least one of the plurality of conductors so that a correspondence between the conductor current and the conductor magnetic flux sensed by the detection element becomes approximately equivalent in each of the plurality of conductors based on a positional relationship between the detection element and each of the plurality of conductors,
the magnetic flux correction mechanism includes an arrangement of magnetic bodies (102a to 102c, 112a to 112c, 122a, 122b) designed based on a positional relationship between the detection element (101, 111, 121) and each of the plurality of conductors,
The arrangement of the magnetic bodies corrects at least one of a magnetic flux density and a magnetic flux direction for the conductor magnetic flux of at least one of the plurality of conductors;
The plurality of conductors (103 to 105, 113 to 115) are arranged at positions in a first direction perpendicular to the top and bottom surfaces of the detection element, and are shifted from each other in a second direction perpendicular to the first direction,
The current sensor (100, 110) includes a sensor lateral magnetic body (102a, 102b, 112a, 112b) arranged in the second direction of the detection element, and a sensor opposing magnetic body (102c, 112c) arranged in a position opposite the detection element via the multiple conductors. A plurality of conductors (103-105, 113-115, 123-125, 133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) each having one end conductively connected to a drive circuit and the other end conductively connected to a rotating electric machine;
and a detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) that senses conductor magnetic fluxes generated by conductor currents flowing through the plurality of conductors, and collectively detects the currents flowing through the plurality of conductors;
A magnetic flux correction mechanism (102a to 102c, 112a to 112c, 122a, 122b, 133 to 135, 143 to 145, 153 to 155, 163 to 165, 173 to 175, 183 to 185, 193 to 195, 203 to 205, 213 to 215, 223 to 225, 233 to 235) is provided that corrects a conductor magnetic flux for at least one of the plurality of conductors so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element becomes approximately equivalent in each of the plurality of conductors based on a positional relationship between the detection element and each of the plurality of conductors,
the magnetic flux correction mechanism includes an arrangement of magnetic bodies (102a to 102c, 112a to 112c, 122a, 122b) designed based on a positional relationship between the detection element (101, 111, 121) and each of the plurality of conductors,
The arrangement of the magnetic bodies corrects at least one of a magnetic flux density and a magnetic flux direction for the conductor magnetic flux of at least one of the plurality of conductors;
The plurality of conductors (123 to 125) are arranged at positions corresponding to the first direction of the detection element, and are shifted from each other in the first direction;
The current sensor (120) includes conductor-side-positioning magnetic bodies (122a, 122b) arranged in a position that is in a second direction relative to the plurality of conductors. A plurality of conductors (103-105, 113-115, 123-125, 133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) each having one end conductively connected to a drive circuit and the other end conductively connected to a rotating electric machine;
and a detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) that senses conductor magnetic fluxes generated by conductor currents flowing through the plurality of conductors, and collectively detects the currents flowing through the plurality of conductors;
A magnetic flux correction mechanism (102a to 102c, 112a to 112c, 122a, 122b, 133 to 135, 143 to 145, 153 to 155, 163 to 165, 173 to 175, 183 to 185, 193 to 195, 203 to 205, 213 to 215, 223 to 225, 233 to 235) is provided that corrects a conductor magnetic flux for at least one of the plurality of conductors so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element becomes approximately equivalent in each of the plurality of conductors based on a positional relationship between the detection element and each of the plurality of conductors,
A combination of the plurality of conductors (133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) designed based on a positional relationship between the detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) and each of the plurality of conductors functions as the magnetic flux correction mechanism ,
The combination of the plurality of conductors is the plurality of conductors (1 73 to 175 , 2 23 to 22 5) that are arranged at a position that is a first direction perpendicular to the top and bottom surfaces of the detection element (1 71 , 2 2 1) and are shifted from each other in a second direction perpendicular to the first direction,
a cross-sectional area of the conductor when the conductor is cut along a plane extending in the first direction and the second direction is defined as a cross-sectional area of the conductor;
the cross-sectional area of each of the plurality of conductors is adjusted based on the positional relationship so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element is approximately equivalent in each of the plurality of conductors;
A current sensor (170, 220) in which the width in the second direction of a near-side conductor (174, 224) that is close to the detection element in the second direction is wider than the width in the second direction of a far-side conductor (173, 175, 223, 225) that is farther from the detection element in the second direction than the near-side conductor, such that the cross-sectional area of the near-side conductor is larger than the cross-sectional area of the far-side conductor . A plurality of conductors (103-105, 113-115, 123-125, 133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) each having one end conductively connected to a drive circuit and the other end conductively connected to a rotating electric machine;
and a detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) that senses conductor magnetic fluxes generated by conductor currents flowing through the plurality of conductors, and collectively detects the currents flowing through the plurality of conductors;
A magnetic flux correction mechanism (102a to 102c, 112a to 112c, 122a, 122b, 133 to 135, 143 to 145, 153 to 155, 163 to 165, 173 to 175, 183 to 185, 193 to 195, 203 to 205, 213 to 215, 223 to 225, 233 to 235) is provided that corrects a conductor magnetic flux for at least one of the plurality of conductors so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element becomes approximately equivalent in each of the plurality of conductors based on a positional relationship between the detection element and each of the plurality of conductors,
A combination of the plurality of conductors (133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) designed based on a positional relationship between the detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) and each of the plurality of conductors functions as the magnetic flux correction mechanism,
The combination of the plurality of conductors is the plurality of conductors (133 to 135, 233 to 235) that are arranged at a position that is a first direction perpendicular to the top and bottom surfaces of the detection element (131, 231) and are shifted from each other in a second direction perpendicular to the first direction,
a cross-sectional area of the conductor when the conductor is cut along a plane extending in the first direction and the second direction is defined as a cross-sectional area of the conductor;
the cross-sectional area of each of the plurality of conductors is adjusted based on the positional relationship so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element is approximately equivalent in each of the plurality of conductors;
The plurality of conductors have a width in the second direction at a center portion (133b, 134b, 135b) narrower than a width in the second direction at both ends (133a, 133c, 134a, 134c, 135a, 135c) in a direction perpendicular to the first direction and the second direction,
A current sensor (130, 230) in which the width in the second direction of a central portion (134b) of a near-side conductor (134, 144, 234) among the plurality of conductors, which is close to the detection element in the second direction, is wider than the width in the second direction of a central portion (133b, 135b) of a far-side conductor (133, 135, 143, 145, 233, 235) which is farther from the detection element in the second direction than the near-side conductor, so that the cross-sectional area of the central portion of the near-side conductor is larger than the cross-sectional area of the central portion of the far-side conductor . A plurality of conductors (103-105, 113-115, 123-125, 133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) each having one end conductively connected to a drive circuit and the other end conductively connected to a rotating electric machine;
and a detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) that senses conductor magnetic fluxes generated by conductor currents flowing through the plurality of conductors, and collectively detects the currents flowing through the plurality of conductors;
A magnetic flux correction mechanism (102a to 102c, 112a to 112c, 122a, 122b, 133 to 135, 143 to 145, 153 to 155, 163 to 165, 173 to 175, 183 to 185, 193 to 195, 203 to 205, 213 to 215, 223 to 225, 233 to 235) is provided that corrects a conductor magnetic flux for at least one of the plurality of conductors so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element becomes approximately equivalent in each of the plurality of conductors based on a positional relationship between the detection element and each of the plurality of conductors,
A combination of the plurality of conductors (133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) designed based on a positional relationship between the detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) and each of the plurality of conductors functions as the magnetic flux correction mechanism ,
The combination of the plurality of conductors is the plurality of conductors ( 163 to 165) that are arranged at a position that is a first direction perpendicular to the top and bottom surfaces of the detection element ( 161 ) and are shifted from each other in a second direction perpendicular to the first direction,
a cross-sectional area of the conductor when the conductor is cut along a plane extending in the first direction and the second direction is defined as a cross-sectional area of the conductor;
the cross-sectional area of each of the plurality of conductors is adjusted based on the positional relationship so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element is approximately equivalent in each of the plurality of conductors;
The plurality of conductors have a width in the first direction at a center portion (163b, 164b, 165b) narrower than a width in the first direction at both ends (163a, 163c, 164a, 164c, 165a, 165c) in a direction perpendicular to the first direction and the second direction,
A current sensor (160) in which the width in the first direction of a central portion (164b) of a near-side conductor (164) among the plurality of conductors, which is close to the detection element in the second direction, is wider than the width in the first direction of a central portion (163b, 165b) of a far-side conductor (163, 165) which is farther from the detection element in the second direction than the near-side conductor, such that the cross-sectional area of the central portion of the near-side conductor is larger than the cross-sectional area of the central portion of the far-side conductor . A plurality of conductors (103-105, 113-115, 123-125, 133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) each having one end conductively connected to a drive circuit and the other end conductively connected to a rotating electric machine;
and a detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) that senses conductor magnetic fluxes generated by conductor currents flowing through the plurality of conductors, and collectively detects the currents flowing through the plurality of conductors;
A magnetic flux correction mechanism (102a to 102c, 112a to 112c, 122a, 122b, 133 to 135, 143 to 145, 153 to 155, 163 to 165, 173 to 175, 183 to 185, 193 to 195, 203 to 205, 213 to 215, 223 to 225, 233 to 235) is provided that corrects a conductor magnetic flux for at least one of the plurality of conductors so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element becomes approximately equivalent in each of the plurality of conductors based on a positional relationship between the detection element and each of the plurality of conductors,
A combination of the plurality of conductors (133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) designed based on a positional relationship between the detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) and each of the plurality of conductors functions as the magnetic flux correction mechanism ,
The combination of the plurality of conductors is the plurality of conductors ( 193-195 , 203-205 ) that are arranged at a position that is a first direction perpendicular to the top and bottom surfaces of the detection element ( 191, 201 ) and are shifted from each other in a second direction perpendicular to the first direction,
a cross-sectional area of the conductor when the conductor is cut along a plane extending in the first direction and the second direction is defined as a cross-sectional area of the conductor;
the cross-sectional area of each of the plurality of conductors is adjusted based on the positional relationship so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element is approximately equivalent in each of the plurality of conductors;
A current sensor (190, 200) in which the width in the first direction of a near-side conductor (194, 204, 234) among the plurality of conductors that is close to the detection element in the second direction is wider than the width in the first direction of a far-side conductor (193, 195, 203, 205, 233, 235) that is farther from the detection element in the second direction than the near-side conductor, so that the cross-sectional area of the near-side conductor is larger than the cross-sectional area of the far-side conductor . the magnetic flux compensation mechanism includes an arrangement of magnetic bodies (102a to 102c, 112a to 112c, 122a, 122b) designed based on the positional relationship,
The arrangement of the magnetic bodies corrects at least one of a magnetic flux density and a magnetic flux direction for the conductor magnetic flux of at least one of the plurality of conductors;
A current sensor as described in any one of claims 3 to 6, wherein the arrangement of the magnetic bodies includes a sensor lateral position magnetic body (102a, 102b, 112a, 112b) arranged in the second direction of the detection element, and a sensor opposing position magnetic body (102c, 112c) arranged in a position opposing the detection element via the multiple conductors. A plurality of conductors (103-105, 113-115, 123-125, 133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) each having one end conductively connected to a drive circuit and the other end conductively connected to a rotating electric machine;
and a detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) that senses conductor magnetic fluxes generated by conductor currents flowing through the plurality of conductors, and collectively detects the currents flowing through the plurality of conductors;
A magnetic flux correction mechanism (102a to 102c, 112a to 112c, 122a, 122b, 133 to 135, 143 to 145, 153 to 155, 163 to 165, 173 to 175, 183 to 185, 193 to 195, 203 to 205, 213 to 215, 223 to 225, 233 to 235) is provided that corrects a conductor magnetic flux for at least one of the plurality of conductors so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element becomes approximately equivalent in each of the plurality of conductors based on a positional relationship between the detection element and each of the plurality of conductors,
A combination of the plurality of conductors (133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) designed based on a positional relationship between the detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) and each of the plurality of conductors functions as the magnetic flux correction mechanism ,
The combination of the plurality of conductors is a plurality of conductors ( 183 to 185) arranged at a position in a first direction perpendicular to the upper and lower surfaces of the detection element ( 181) and shifted from each other in the first direction,
a second direction is a direction perpendicular to the first direction and a direction in which current flows through each of the plurality of conductors;
a cross-sectional area of the conductor when the conductor is cut along a plane extending in the first direction and the second direction is defined as a cross-sectional area of the conductor;
the cross-sectional area of each of the plurality of conductors is adjusted based on the positional relationship so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element is approximately equivalent in each of the plurality of conductors;
A current sensor (180) in which the width in the second direction of a near-vertical conductor (183) among the plurality of conductors, which is close to the detection element in the first direction, is wider than the width in the second direction of a far-vertical conductor (184, 185) which is farther from the detection element in the first direction than the near-vertical conductor, such that the cross-sectional area of the near-vertical conductor is larger than the cross-sectional area of the far - vertical conductor. A plurality of conductors (103-105, 113-115, 123-125, 133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) each having one end conductively connected to a drive circuit and the other end conductively connected to a rotating electric machine;
and a detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) that senses conductor magnetic fluxes generated by conductor currents flowing through the plurality of conductors, and collectively detects the currents flowing through the plurality of conductors;
A magnetic flux correction mechanism (102a to 102c, 112a to 112c, 122a, 122b, 133 to 135, 143 to 145, 153 to 155, 163 to 165, 173 to 175, 183 to 185, 193 to 195, 203 to 205, 213 to 215, 223 to 225, 233 to 235) is provided that corrects a conductor magnetic flux for at least one of the plurality of conductors so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element becomes approximately equivalent in each of the plurality of conductors based on a positional relationship between the detection element and each of the plurality of conductors,
A combination of the plurality of conductors (133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) designed based on a positional relationship between the detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) and each of the plurality of conductors functions as the magnetic flux correction mechanism,
The combination of the plurality of conductors is a plurality of conductors (153 to 155) arranged at positions in a first direction perpendicular to the top and bottom surfaces of the detection element (151) and shifted from each other in the first direction,
a second direction is a direction perpendicular to the first direction and a direction in which current flows through each of the plurality of conductors;
a cross-sectional area of the conductor when the conductor is cut along a plane extending in the first direction and the second direction is defined as a cross-sectional area of the conductor;
the cross-sectional area of each of the plurality of conductors is adjusted based on the positional relationship so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element is approximately equivalent in each of the plurality of conductors;
The plurality of conductors have a width in the second direction at a center portion (153b, 154b, 155b) narrower than a width in the second direction at both ends (153a, 153c, 154a, 154c, 155a, 155c) in the current flow direction,
A current sensor (150) in which the width in the second direction of a central portion (153b) of a near-vertical conductor (153) among the plurality of conductors, which is close to the detection element in the first direction, is wider than the width in the second direction of central portions (154b, 155b) of far-vertical conductors (154, 155) which are farther from the detection element in the first direction than the near-vertical conductor, so that the cross-sectional area of the central portion of the near-vertical conductor is larger than the cross-sectional area of the central portion of the far- vertical conductor . A plurality of conductors (103-105, 113-115, 123-125, 133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) each having one end conductively connected to a drive circuit and the other end conductively connected to a rotating electric machine;
and a detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) that senses conductor magnetic fluxes generated by conductor currents flowing through the plurality of conductors, and collectively detects the currents flowing through the plurality of conductors;
A magnetic flux correction mechanism (102a to 102c, 112a to 112c, 122a, 122b, 133 to 135, 143 to 145, 153 to 155, 163 to 165, 173 to 175, 183 to 185, 193 to 195, 203 to 205, 213 to 215, 223 to 225, 233 to 235) is provided that corrects a conductor magnetic flux for at least one of the plurality of conductors so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element becomes approximately equivalent in each of the plurality of conductors based on a positional relationship between the detection element and each of the plurality of conductors,
A combination of the plurality of conductors (133-135, 143-145, 153-155, 163-165, 173-175, 183-185, 193-195, 203-205, 213-215, 223-225, 233-235) designed based on a positional relationship between the detection element (101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 211, 221, 231) and each of the plurality of conductors functions as the magnetic flux correction mechanism,
The combination of the plurality of conductors is a plurality of conductors ( 213 to 215) arranged at a position in a first direction perpendicular to the upper and lower surfaces of the detection element ( 211) and shifted from each other in the first direction,
a second direction is a direction perpendicular to the first direction and a direction in which current flows through each of the plurality of conductors;
a cross-sectional area of the conductor when the conductor is cut along a plane extending in the first direction and the second direction is defined as a cross-sectional area of the conductor;
the cross-sectional area of each of the plurality of conductors is adjusted based on the positional relationship so that a corresponding relationship between the conductor current and the conductor magnetic flux sensed by the detection element is approximately equivalent in each of the plurality of conductors;
A current sensor (210) in which the width in the first direction of a near vertical conductor (213) among the plurality of conductors, which is close to the detection element in the first direction , is wider than the width in the first direction of a far vertical conductor (214, 215) which is farther from the detection element in the first direction than the near vertical conductor, such that the cross-sectional area of the near vertical conductor is larger than the cross-sectional area of the far vertical conductor . the magnetic flux compensation mechanism includes an arrangement of magnetic bodies (102a to 102c, 112a to 112c, 122a, 122b) designed based on the positional relationship,
The arrangement of the magnetic bodies corrects at least one of a magnetic flux density and a magnetic flux direction for the conductor magnetic flux of at least one of the plurality of conductors;
The current sensor according to any one of claims 8 to 10 , wherein the arrangement of the magnetic bodies includes conductor lateral position magnetic bodies (122a, 122b) arranged in a position that is in a second direction relative to the plurality of conductors.

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