Magnetic sensor device, transducer device and battery device

Abstract

The present invention relates to a magnetic sensor device, a transducer device, and a battery device. The magnetic sensor device includes a first detection circuit that generates a first detection signal, a coil that generates a canceling magnetic field by flowing a feedback current, a second detection circuit that generates a second detection signal having a correspondence with a value of the feedback current, and a control circuit that controls the feedback current. In a closed loop operation, the control circuit controls the feedback current so that the first detection signal becomes a certain value. In an open loop operation, the control circuit maintains the feedback current at a certain value.

Description

Technical Field

[0001] The present invention relates to a magnetic sensor device, an inverter device including a magnetic sensor device, and a battery device including a magnetic sensor device. Background Technology

[0002] Vehicles that use electric motors, such as electric vehicles, hybrid electric vehicles, and plug-in hybrid electric vehicles, are equipped with a converter device that controls the electric motor and a battery device that supplies high-voltage power to the electric motor via the converter device. In the converter device and the battery device, a current sensor is used to measure the current flowing in the circuit. As a current sensor used in circuits through which large currents flow, such as converter devices and battery devices, a non-contact magnetic current sensor is known.

[0003] As magnetic current sensors, there are known magnetic proportional current sensors and magnetic balance current sensors. In a magnetic proportional current sensor, the magnetic sensor, which includes a magnetic detection element, detects the magnetic field generated by the current flowing through the conductor, generating a detection value that corresponds to the strength of the magnetic field. The detection value of the magnetic sensor is proportional to the value of the current being detected. Therefore, the detection value of the magnetic sensor is equivalent to the detection value of the current being detected.

[0004] A magnetically balanced current sensor includes: a feedback coil that generates a neutralizing magnetic field to eliminate the magnetic field generated by a current flowing in the conductor; a magnetic sensor that detects the residual magnetic field between the target magnetic field and the neutralizing magnetic field (hereinafter referred to as the residual magnetic field) and outputs the detected value of the residual magnetic field; a control circuit that controls a feedback current flowing in the feedback coil based on the detected value output from the magnetic sensor; and a detection circuit comprising a resistor inserted into the current path of the feedback current. The potential difference across the resistor corresponds to the detected value of the feedback current. The detected value of the feedback current is proportional to the value of the target current. Therefore, the detected value of the feedback current is equivalent to the detected value of the target current. This magnetically balanced current sensor operates such that the strength of the residual magnetic field approaches zero.

[0005] In converter devices and battery devices, current sensors with a wide measurement range are particularly needed. Chinese Patent Application Publication No. 102812366A, Japanese Patent Application Publication No. 2007-78416, and Japanese Patent Application Publication No. 2011-169833 disclose current sensors that combine magnetic proportional and magnetic balance methods to expand the measurement range.

[0006] However, in battery devices, to effectively utilize battery capacity, there is a requirement to accurately estimate the remaining battery capacity based on the cumulative value of measured current. To accurately estimate the remaining battery capacity, it is particularly important to measure the target current with high precision in regions where the value of the target current decreases, i.e., regions where the strength of the target magnetic field decreases. Magnetic balance methods, in principle, eliminate the offset and nonlinearity of the magnetic detection element. Therefore, in regions where the strength of the target magnetic field decreases, it is preferable to measure the target current using a magnetic balance method.

[0007] Japanese Patent Application Publication No. 2007-78416 describes a method where, when the detected current is low, a magnetic balance-based current sensor is selected, and the value of the output signal (Hall voltage) from the integrated chip is proportional to the value of the detected current. Japanese Patent Application Publication No. 2011-169833 describes using an output voltage consistent with the characteristics of a magnetic balance-based current sensor as the output when the current input range is relatively narrow; and in the low current region, both the output voltage consistent with the characteristics of a magnetic balance-based current sensor and the output voltage in a magnetic proportional current sensor are proportional to the value of the measured current.

[0008] Sometimes, a noisy magnetic field with a rapidly changing intensity is applied to current sensors used in vehicles. This noisy magnetic field will be referred to below as a pulsed noise magnetic field. Detection of pulsed noise magnetic fields is advantageous from the viewpoint of anomaly detection. However, existing technology does not consider detecting pulsed noise magnetic fields in current sensors. Furthermore, magnetically balanced current sensors are inherently slower in response compared to magnetically proportional current sensors. That is, in magnetically balanced current sensors, even when a pulsed noise magnetic field is applied, the detected value of the feedback current hardly changes, making it impossible to detect pulsed noise magnetic fields.

[0009] The above problems are not limited to current sensors, but also apply to all magnetic sensor devices that detect the magnetic field of an object. Summary of the Invention

[0010] The purpose of this invention is to provide a magnetic sensor device, a transducer device, and a battery device capable of detecting pulsed noise magnetic fields.

[0011] The magnetic sensor device of the present invention includes: a first detection circuit comprising a magnetic detection element for detecting an applied magnetic field and generating a first detection signal corresponding to the strength of the applied magnetic field; a feedback coil that generates a canceling magnetic field for canceling at least a portion of the target magnetic field, which is the target magnetic field, by means of a feedback current flowing through it; a second detection circuit that generates a second detection signal corresponding to the value of the feedback current; and a control circuit that controls the feedback current and generates a detection value corresponding to the strength of the target magnetic field.

[0012] The control circuit is configured to perform a closed-loop operation when the strength of the object's magnetic field is greater than a first value and less than a second value, and an open-loop operation when the strength of the object's magnetic field is less than the first value or greater than the second value. The closed-loop operation involves the control circuit controlling the feedback current to ensure that the first detection signal reaches a certain value. The open-loop operation involves the control circuit maintaining the feedback current at a certain value. During the closed-loop operation, the control circuit generates a detection value based on the second detection signal; during the open-loop operation, it generates a detection value based on the first detection signal.

[0013] In the magnetic sensor device of the present invention, the control circuit may also maintain the feedback current at a certain value when performing open-loop operation, so that the absolute value of the strength of the eliminated magnetic field is equal to the absolute value of the first value or the absolute value of the second value.

[0014] Furthermore, in the magnetic sensor device of the present invention, the magnetic detection element can also be a magnetoresistive element. The magnetoresistive element can also be a tunneling magnetoresistive element.

[0015] Furthermore, in the magnetic sensor device of the present invention, the control circuit may also be configured to detect a pulsed noise magnetic field overlapping with the applied magnetic field using a first detection signal, or a signal obtained by combining the first detection signal and the second detection signal. The maximum value of the intensity of the pulsed noise magnetic field may also be greater than the second value. The minimum value of the intensity of the pulsed noise magnetic field may also be less than the first value.

[0016] Furthermore, in the magnetic sensor device of the present invention, the gradient of the change in the first detection signal relative to the change in the strength of the object's magnetic field during the execution of the open-loop operation may be different from, or smaller than, the gradient of the change in the second detection signal relative to the change in the strength of the object's magnetic field during the execution of the closed-loop operation.

[0017] In addition, the magnetic sensor device of the present invention may also include a shielding component that concentrates magnetic flux in the vicinity of the magnetic detection element.

[0018] Furthermore, in the magnetic sensor device of the present invention, the target magnetic field can also be a magnetic field generated by the target current flowing in the conductor. In this case, the detected value can also correspond to the target current. Alternatively, a magnetic core for accumulating the magnetic flux generated by the target current may not be provided in the conductor.

[0019] The converter device of the present invention includes the magnetic sensor device of the present invention and the converter circuit containing conductors.

[0020] The battery device of the present invention includes the magnetic sensor device of the present invention, a power supply circuit containing conductors, and a battery connected to the power supply circuit.

[0021] In the magnetic sensor device, converter device, and battery device of the present invention, during the execution of closed-loop operation, the control circuit controls the feedback current to make the first detection signal a constant value. Therefore, according to the present invention, it is possible to detect pulsed noise magnetic fields.

[0022] Other objects, features and benefits of the present invention will become quite clear from the following description. Attached Figure Description

[0023] Figure 1 This is a perspective view showing the structure of a current sensor system incorporating the magnetic sensor device according to the first embodiment of the present invention.

[0024] Figure 2 This is a block diagram showing the structure of the magnetic sensor device according to the first embodiment of the present invention.

[0025] Figure 3 This is a cross-sectional view showing the magnetic sensor according to the first embodiment of the present invention.

[0026] Figure 4 This is a perspective view showing the magnetoresistive effect element of the magnetic sensor device according to the first embodiment of the present invention.

[0027] Figure 5 This is a characteristic diagram showing the relationship between the object's magnetic field and the feedback current in the first embodiment of the present invention.

[0028] Figure 6 This is a characteristic diagram showing the relationship between the object's magnetic field and the second detection signal in the first embodiment of the present invention.

[0029] Figure 7 This is a characteristic diagram showing the relationship between the object's magnetic field and the first detection signal in the first embodiment of the present invention.

[0030] Figure 8A and Figure 8B This is a schematic diagram illustrating the applied magnetic field and the pulsed noise magnetic field in the first embodiment of the present invention.

[0031] Figure 9A and Figure 9B This is a schematic diagram illustrating the pulsed noise magnetic field superimposed on the first and second detection signals when the magnetic field is applied, according to the first embodiment of the present invention.

[0032] Figure 10 This is a block diagram illustrating the structure of the converter device and battery device according to the first embodiment of the present invention.

[0033] Figure 11 This is a cross-sectional view showing the magnetic sensor according to the second embodiment of the present invention. Detailed Implementation

[0034] [First Implementation]

[0035] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, referring to... Figure 1 The structure of a current sensor system including the magnetic sensor device of the first embodiment of the present invention will be described. The magnetic sensor device 1 of this embodiment is used as a current sensor to detect the value of the current flowing through a conductor. Figure 1 The diagram illustrates an example where the conductor through which the current to be detected flows is a bus bar 2. A magnetic sensor device 1 is positioned near the bus bar 2. Hereinafter, the current to be detected will be denoted as the target current Itg. A magnetic field 3 is generated around the bus bar 2 due to the target current Itg. The magnetic sensor device 1 is positioned at the location where the magnetic field 3 is applied.

[0036] In this design, the busbar 2 does not have a magnetic core for collecting the magnetic flux generated by the object current Itg. This allows for the miniaturization of the magnetic sensor device 1.

[0037] Next, refer to Figures 1 to 3 The structure of the magnetic sensor device 1 will be described in detail. Figure 2 This is a block diagram showing the structure of the magnetic sensor device 1. Figure 3 This is a cross-sectional view of the magnetic sensor. The magnetic sensor device 1 includes: a first detection circuit 5, a feedback coil (hereinafter referred to as coil) 12, a second detection circuit 6, and a control circuit 23.

[0038] The first detection circuit 5 includes a magnetic detection element that detects the applied magnetic field and generates a first detection signal S1 that corresponds to the strength of the applied magnetic field. Here, the magnetic field applied to the magnetic detection element of the first detection circuit 5 in the magnetic field 3 generated by the object current Itg is referred to as the object magnetic field or object magnetic field H1. The coil 12 is used to generate a canceling magnetic field H2 to cancel at least a portion of the object magnetic field H1 by passing a feedback current Icc. The second detection circuit 6 generates a second detection signal S2 that corresponds to the value of the feedback current Icc.

[0039] Control circuit 23 controls the feedback current Icc and generates a detection value Vs that corresponds to the strength of the object's magnetic field H1. Control circuit 23 generates the detection value Vs based on either the first detection signal S1 or the second detection signal S2, which will be explained in detail later.

[0040] The portion including the magnetic detection element and coil 12 and the portion including the control circuit 23 can be either integrated or separate. In this embodiment, the two portions are separate. Hereinafter, the portion including the magnetic detection element and coil 12 will be referred to as the magnetic sensor 10, and the portion including the control circuit 23 will be referred to as the processor 20. The magnetic sensor 10 is independent of the busbar 2. The processor 20 is, for example, composed of an application-specific integrated circuit (ASIC) or a microcomputer. The processor 20 can be configured close to the magnetic sensor 10 or far away from the magnetic sensor 10.

[0041] like Figure 2 As shown, in addition to the coil 12, the magnetic sensor 10 also includes a Wheatstone bridge circuit 11 and a resistor 13. The Wheatstone bridge circuit 11 includes resistors R1, R2, R3, and R4, each containing a magnetic detection element.

[0042] like Figure 3 As shown, the magnetic sensor 10 also includes a magnetic detection element (in Figure 3 The shield 14 is located near the Wheatstone bridge circuit 11. The shield 14 is made of magnetic material and has the function of focusing magnetic flux. By providing the shield 14, the range of applied magnetic field strength that can be detected by the magnetic detection element can be expanded, i.e., the dynamic range can be increased. The Wheatstone bridge circuit 11, the coil 12, and the shield 14 are integrated through multiple insulating layers. The resistor 13 can be mounted on the surface of the outermost insulating layer or embedded in multiple insulating layers.

[0043] Here, as Figure 1 and Figure 2 As shown, the X, Y, and Z directions are defined. The X, Y, and Z directions are orthogonal to each other. Furthermore, in this application, "orthogonal" means not only perfectly orthogonal at 90°, but also approximately orthogonal, that is, orthogonal slightly deviating from 90°. In this embodiment, [the following is a more detailed description of the orthogonal directions]. Figure 1 The direction of the current Itg flowing in the object shown is defined as the Y direction. Furthermore, the direction opposite to the X direction is defined as the -X direction, the direction opposite to the Y direction as the -Y direction, and the direction opposite to the Z direction as the -Z direction. Additionally, hereinafter, the position located in front of the reference point in the Z direction is referred to as "above," and the position located on the opposite side of the reference point is referred to as "below."

[0044] The magnetic sensor 10 is positioned above or below the busbar 2. Figure 1 This illustrates an example where a magnetic sensor device 1, including a magnetic sensor 10, is positioned above a busbar 2.

[0045] like Figure 3 As shown, the magnetic sensor 10 also includes a substrate 61 and insulating layers 62, 63, 64, 65, 66, 67, and 68. Insulating layers 62, 63, and 64 are stacked on the substrate 61. A Wheatstone bridging circuit 11 is disposed on insulating layer 64. Insulating layer 65 is disposed on insulating layer 64 to cover the Wheatstone bridging circuit 11. Insulating layers 66 and 67 are stacked on insulating layer 65. A shielding element 14 is disposed on insulating layer 67. An insulating layer 68 is disposed on insulating layer 67 to cover the shielding element 14. A coil 12 is embedded in insulating layers 63 to 66.

[0046] like Figure 2 As shown, the magnetic sensor 10 has ports E11, E12, E13, E14, G1, P1, and V1. One end of each of the resistors R1 and R2 in the Wheatstone bridge circuit 11 is connected to port E11. One end of each of the resistors R3 and R4 in the Wheatstone bridge circuit 11 is connected to port E12. The other end of each of the resistors R1 and R3 is connected to port V1. The other end of each of the resistors R2 and R4 is connected to port G1.

[0047] One end of coil 12 is connected to port P1. The other end of coil 12 and one end of resistor 13 are connected to port E13. The other end of resistor 13 is connected to port E14.

[0048] like Figure 2 As shown, processor 20 has ports E20, E21, E22, E23, E24, G2, P2, and V2. Ports E21, E22, E23, E24, G2, P2, and V2 are connected to ports E11, E12, E13, E14, G1, P1, and V1 of magnetic sensor 10, respectively. A specified power supply voltage is applied to port V2 to supply the Wheatstone bridge circuit 11 of magnetic sensor 10. Port G2 is grounded. Control circuit 23 outputs a detection value Vs to port E20.

[0049] In addition to the control circuit 23, the processor 20 also includes a first amplifier circuit 21, a second amplifier circuit 22, and a driver circuit 24. The first and second amplifier circuits 21 and 22 each have two input terminals and one output terminal. The two input terminals of the first amplifier circuit 21 are connected to ports E21 and E22, respectively. The two input terminals of the second amplifier circuit 22 are connected to ports E23 and E24, respectively. The output terminals of the first amplifier circuit 21 and the second amplifier circuit 22 are connected to the control circuit 23.

[0050] The drive circuit 24 supplies the feedback current Icc to the coil 12. The control circuit 23 controls the feedback current Icc by controlling the drive circuit 24. The feedback current Icc is supplied to the coil 12 via ports P1 and P2.

[0051] The first detection circuit 5 consists of the Wheatstone bridge circuit 11 of the magnetic sensor 10 and the first amplifier circuit 21 of the processor 20. The second detection circuit 6 consists of the resistor 13 of the magnetic sensor 10 and the second amplifier circuit 22 of the processor 20.

[0052] Next, the magnetic detection element included in the first detection circuit 5 will be described. The magnetic detection element can be a Hall element or a magnetoresistive element. However, from the viewpoint of response speed, a magnetoresistive element is preferred. Hereinafter, the magnetoresistive element will be referred to as an MR element. The MR element can be a spin-valve type MR element or an AMR (anisotropic magnetoresistive) element. In this embodiment, the first detection circuit 5 specifically includes a spin-valve type MR element 50 as the magnetic detection element.

[0053] Figure 4 This is a perspective view of an MR element 50. The MR element 50 includes: a magnetized fixed layer 52 with a fixed orientation; a magnetized free layer 54 with an orientation that can change according to the direction of an applied magnetic field; and a gap layer 53 disposed between the magnetized fixed layer 52 and the free layer 54. The MR element 50 can be a TMR (tunneling magnetoresistance) element or a GMR (giant magnetoresistance) element, but from the viewpoint of response speed and accuracy, a TMR element is preferred. In a TMR element, the gap layer 53 is a tunnel barrier layer. In a GMR element, the gap layer 53 is a non-magnetic conductive layer. In the MR element 50, the resistance value varies according to the angle formed by the magnetization direction of the free layer 54 relative to the magnetization direction of the magnetized fixed layer 52, with the resistance value being at its minimum at 0° and at its maximum at 180°. In the MR element 50, the free layer 54 has an anisotropic shape with its easy magnetization axis orthogonal to the magnetization direction of the magnetized fixed layer 52.

[0054] The MR element 50 also includes an antiferromagnetic layer 51. The antiferromagnetic layer 51, the magnetization fixation layer 52, the gap layer 53, and the free layer 54 are stacked sequentially. Furthermore, the arrangement of layers 51 to 54 in the MR element 50 can also be... Figure 4The configuration shown is reversed top to bottom. The antiferromagnetic layer 51 is made of an antiferromagnetic material and generates exchange coupling with the magnetization fixing layer 52, fixing the magnetization direction of the magnetization fixing layer 52. Alternatively, the magnetization fixing layer 52 can also be a so-called self-pilling type fixing layer (Synthetic FerriPinned layer, SFP layer). A self-pilling type fixing layer has a stacked ferrimagnetic structure consisting of a ferromagnetic layer, a non-magnetic intermediate layer, and a ferromagnetic layer, formed by antiferromagnetic coupling of two ferromagnetic layers. When the magnetization fixing layer 52 is a self-pilling type fixing layer, the antiferromagnetic layer 51 can be omitted.

[0055] The resistive sections R1 to R4 of the Wheatstone bridge circuit 11 each include at least one MR element 50. The magnetization direction of the magnetization fixing layer 52 of the MR element 50 in each of the resistive sections R1 and R4 is a first magnetization direction. The magnetization direction of the magnetization fixing layer 52 of the MR element 50 in each of the resistive sections R2 and R3 is a second magnetization direction, which is opposite to the first magnetization direction.

[0056] Next, the position and orientation of the magnetic sensor 10 will be described. A magnetic field 3 generated by the object current Itg and a magnetic field generated by the coil 12 are applied to the magnetic sensor 10. The magnetic sensor 10 is positioned where the directions of the two applied magnetic fields are opposite or approximately opposite to each other.

[0057] Here, the direction parallel to the directions of the two magnetic fields applied to the magnetic sensor 10 is referred to as the magnetic sensing direction. The target magnetic field H1 is the component of the magnetic field 3 generated by the target current Itg and applied to the magnetic sensor 10, which is parallel to the magnetic sensing direction. Furthermore, the elimination magnetic field H2 is the component of the magnetic field generated by the coil 12 and applied to the magnetic sensor 10, which is parallel to the magnetic sensing direction.

[0058] Generally, planar Hall elements tend to have a sensitivity axis perpendicular to the substrate, while MR elements and vertical Hall elements tend to have a sensitivity axis parallel to the substrate. When the MR element is a TMR element or a GMR element, the direction parallel to the magnetization direction of the magnetization fixing layer is generally taken as the magnetic sensing direction. Therefore, when the MR element 50 is a TMR element or a GMR element, the magnetic sensor 10 is configured with the first and second magnetization directions parallel or approximately parallel to the magnetic sensing direction.

[0059] Here, the direction of the target magnetic field H1 and the direction of the demagnetizing magnetic field H2 are set to be parallel to the X direction. In this case, the magnetic sensor 10 is configured, for example, with the first magnetization direction as the X direction and the second magnetization direction as the -X direction. Furthermore, from the viewpoint of manufacturing accuracy of the MR element 50 and alignment accuracy of the magnetic sensor 10, the first and second magnetization directions can also be slightly deviated from the directions described above.

[0060] The free layer 54 of the MR element 50 preferably has a shape anisotropy with the direction intersecting the magnetic induction direction as the easy axis. In addition, by providing a magnet that applies a bias magnetic field to the free layer 54 of the MR element 50, the direction intersecting the magnetic induction direction can be made to be the easy axis.

[0061] Next, the operation of the control circuit 23 will be explained. The control circuit 23 can select between closed-loop and open-loop operation. In closed-loop operation, the control circuit 23 controls the feedback current Icc to make the first detection signal S1 a constant value. In open-loop operation, the control circuit 23 maintains the feedback current Icc at a constant value. When performing closed-loop operation, the magnetic sensor device 1 operates as a magnetically balanced current sensor. When performing open-loop operation, the magnetic sensor device 1 operates as a magnetically proportional current sensor.

[0062] If the strength of the applied magnetic field changes, the potential difference between ports E11 and E12 of the magnetic sensor 10 changes. Consequently, the potential difference between ports E21 and E22 of the processor 20 changes. The first amplifier circuit 21 outputs the signal corresponding to the potential difference between ports E21 and E22 as the first detection signal S1. In the absence of a noise magnetic field, the applied magnetic field is the magnetic field that compensates for the difference between the target magnetic field H1 and the elimination magnetic field H2 (hereinafter referred to as the residual magnetic field). During the execution of the closed-loop operation, the control circuit 23 controls the feedback current Icc based on the value of the first detection signal S1 to bring the strength of the residual magnetic field close to zero. Therefore, during the execution of the closed-loop operation, the value of the first detection signal S1 remains constant (e.g., zero).

[0063] If the value of the feedback current Icc changes, the potential difference between ports E13 and E14 of the magnetic sensor 10 changes. Consequently, the potential difference between ports E23 and E24 of the processor 20 changes. The second amplifier circuit 22 outputs the signal corresponding to the potential difference between ports E23 and E24 as the second detection signal S2. During the execution of the closed-loop operation, the value of the second detection signal S2 corresponds to the strength of the object magnetic field H1 and the value of the object current Itg. During the execution of the closed-loop operation, the control circuit 23 generates a detection value Vs based on the second detection signal S2. The detection value Vs is generated, for example, by applying specified corrections such as gain adjustment and offset adjustment to the second detection signal S2.

[0064] During open-loop operation, control circuit 23 maintains the feedback current Icc at a constant value. Therefore, during open-loop operation, the strength of the residual magnetic field varies according to the strength of the object magnetic field H1. During open-loop operation, the value of the first detection signal S1 corresponds to the strength of the object magnetic field H1 and the value of the object current Itg. During open-loop operation, control circuit 23 generates a detection value Vs based on the first detection signal S1. The detection value Vs is generated, for example, by applying specified corrections such as gain adjustment and offset adjustment to the first detection signal S1.

[0065] In this embodiment, the control circuit 23 is specifically configured to perform a closed-loop operation when the strength of the target magnetic field H1 is greater than a first value and less than a second value, and to perform an open-loop operation when the strength of the target magnetic field H1 is less than the first value or greater than the second value. During the closed-loop operation, the control circuit 23 controls the feedback current Icc to make the strength of the residual magnetic field zero, i.e., the target magnetic field H1 is completely canceled by the elimination magnetic field H2. During the open-loop operation, the control circuit 23 maintains the feedback current Icc at a constant value so that a portion of the target magnetic field H1 is canceled by the elimination magnetic field H2.

[0066] Here, a positive value represents the strength of the magnetic field when the direction of the magnetic field is X, and a negative value represents the strength of the magnetic field when the direction of the magnetic field is -X. In this embodiment, the first value is negative and the second value is positive.

[0067] Figure 5 This is a characteristic graph showing the relationship between the strength of the object's magnetic field H1 and the feedback current Icc. In Figure 5 In the diagram, the horizontal axis represents the strength of the object's magnetic field H1, and the vertical axis represents the feedback current Icc. Furthermore, in... Figure 5 In this context, the strength of the target magnetic field H1 is represented by the value of the magnetic flux density corresponding to the strength of the magnetic field H1. In the following explanation, the strength of the magnetic field is represented by the value of the magnetic flux density corresponding to the strength of the magnetic field. Furthermore, when the direction of the target magnetic field H1 is the -X direction (the direction of the eliminating magnetic field H2 is the X direction), the direction of the feedback current Icc flowing in coil 12 is opposite to the direction when the direction of the target magnetic field H1 is the X direction (the direction of the eliminating magnetic field H2 is the -X direction). However, in Figure 5 In this context, regardless of the direction of the feedback current Icc, the value of the feedback current Icc is represented by a positive value.

[0068] exist Figure 5 In the example shown, the first value is set to -10mT, and the second value is set to 10mT. For example... Figure 5As shown, when the strength of the target magnetic field H1 increases from 0, the feedback current Icc increases until the strength of the target magnetic field H1 reaches 10mT. When the strength of the target magnetic field H1 becomes 10mT or higher, the feedback current Icc is maintained at a constant value. When the strength of the target magnetic field H1 is 10mT or higher, the control circuit 23 maintains the feedback current Icc at a constant value so that the absolute value of the strength of the eliminated magnetic field H2 is equal to the absolute value of the second value (10mT).

[0069] Similarly, as the strength of the target magnetic field H1 decreases from 0, the feedback current Icc increases until the strength of the target magnetic field H1 reaches -10mT. When the strength of the target magnetic field H1 falls below -10mT, the feedback current Icc is maintained at a constant value. When the strength of the target magnetic field H1 falls below -10mT, the control circuit 23 maintains the feedback current Icc at a constant value so that the absolute value of the strength of the eliminated magnetic field H2 is equal to the absolute value of the first value (10mT).

[0070] Figure 6 This is a characteristic graph showing the relationship between the strength of the object's magnetic field H1 and the second detection signal S2. Figure 6 In the diagram, the horizontal axis represents the strength of the object's magnetic field H1, and the vertical axis represents the second detection signal S2. For example... Figure 6 As shown, when the strength of the object magnetic field H1 is greater than -10 mT and less than 10 mT, the second detection signal S2 varies according to the strength of the object magnetic field H1. When the strength of the object magnetic field H1 is below -10 mT or above 10 mT, the second detection signal S2 becomes a constant value independent of the strength of the object magnetic field H1.

[0071] Figure 7 This is a characteristic graph showing the relationship between the strength of the object's magnetic field H1 and the first detection signal S1. Figure 7 In the diagram, the horizontal axis represents the strength of the object's magnetic field H1, and the vertical axis represents the first detection signal S1. For example... Figure 7 As shown, when the strength of the object magnetic field H1 is greater than -10 mT and less than 10 mT, the first detection signal S1 becomes a constant value regardless of the strength of the object magnetic field H1. When the strength of the object magnetic field H1 is below -10 mT or above 10 mT, the first detection signal S1 varies according to the strength of the object magnetic field H1.

[0072] Furthermore, the gradient of the change in the first detection signal S1 relative to the change in the intensity of the object's magnetic field H1 during the execution of the open-loop action can also differ from the gradient of the change in the second detection signal S2 relative to the change in the intensity of the object's magnetic field H1 during the execution of the closed-loop action. Figure 6 and Figure 7In the example shown, the gradient of the change in the first detection signal S1 relative to the change in the intensity of the object magnetic field H1 during the execution of the open-loop action is smaller than the gradient of the change in the second detection signal S2 relative to the change in the intensity of the object magnetic field H1 during the execution of the closed-loop action.

[0073] Next, the operation and effects of the magnetic sensor device 1 in this embodiment will be explained. In this embodiment, the control circuit 23 is configured to perform a closed-loop operation when the strength of the target magnetic field H1 is greater than a first value and less than a second value. That is, in this embodiment, the magnetic sensor device 1 is configured to operate as a magnetically balanced current sensor in the region where the absolute value of the strength of the target magnetic field H1 decreases. Therefore, according to this embodiment, the target current Itg can be detected with high precision in the region where the strength of the target magnetic field H1 decreases. During the execution of the closed-loop operation, the second detection signal S2 corresponds to the detection value of the magnetically balanced current sensor.

[0074] Furthermore, in this embodiment, the control circuit 23 is configured to perform open-loop operation when the strength of the target magnetic field H1 is below a first value or above a second value. That is, in this embodiment, the magnetic sensor device 1 is configured to operate as a magnetic proportional current sensor in the region where the absolute value of the strength of the target magnetic field H1 increases. Therefore, according to this embodiment, the measurement range of the target current Itg can be expanded. The first detection signal S1 during the execution of the open-loop operation corresponds to the detection value of the magnetic proportional current sensor.

[0075] Furthermore, according to this embodiment, it is possible to detect noise magnetic fields whose intensity changes instantaneously (pulsating noise magnetic fields). Hereinafter, refer to... Figures 8A to 9B Explain this effect. Figure 8A and Figure 8B This is a schematic diagram representing the application of a magnetic field and a pulsed noise magnetic field. Figure 8A This refers to an applied magnetic field that overlaps with a pulsed, noisy magnetic field. Figure 8B The amplified representation indicates a pulsed noise magnetic field.

[0076] Figure 9A and Figure 9B This is a schematic diagram representing the pulsed noise magnetic field superimposed on the first and second detection signals S1 and S2 when the magnetic field is applied. Figure 9A This represents the second detection signal S2. Figure 9B This represents the first detection signal S1. Furthermore, in Figure 9A In this process, the second detection signal S2 is standardized such that its maximum value is 1 and its minimum value is -1 when there is no noise magnetic field. Furthermore, in... Figure 9BIn this process, the first detection signal S1 is standardized by setting the maximum value of the first detection signal S1 under the condition of no noise magnetic field to 1 and the minimum value of the first detection signal S1 under the condition of no noise magnetic field to -1.

[0077] exist Figure 8A and Figure 9B The example shown illustrates a pulse-like noise magnetic field that instantaneously increases the intensity of the applied magnetic field during the execution of a closed-loop action. The second detection signal S2 varies according to the feedback current Icc. The feedback current Icc is controlled by the control circuit 23 and the drive circuit 24. Therefore, the response speed of the second detection signal S2 is theoretically slower. Therefore, as... Figure 9A As shown, even when the pulsed noise magnetic fields overlap, the second detection signal S2 remains almost unchanged.

[0078] On the other hand, since the control circuit 23 and the drive circuit 24 are not interrupted, the response speed of the first detection signal S1 is faster than that of the second detection signal S2. In this embodiment, a high-response, high-precision MR element 50 (TMR element) is used, particularly as a magnetic detection element. Therefore, as Figure 9B As shown, when pulsed noise magnetic fields overlap, the value of the first detection signal S1 changes according to the pulsed noise magnetic field. Although not shown, during the execution of open-loop operation, when pulsed noise magnetic fields overlap, the value of the first detection signal S1 also changes according to the pulsed noise magnetic field. Therefore, by monitoring the first detection signal S1, the pulsed noise magnetic field can be detected.

[0079] The control circuit 23 can also be configured to output a signal Sp to port E20 or a port not shown, indicating that a pulsed noise magnetic field has been detected.

[0080] In addition, Figure 8A and Figure 9B The diagram illustrates the overlapping of pulsed, noisy magnetic fields with varying intensity. However, referring to... Figure 8A and Figure 9B The same series of explanations also apply to the case of overlapping pulsed noisy magnetic fields with decreasing magnetic field strength.

[0081] When a pulsed noise magnetic field is a magnetic field in which the intensity of the applied magnetic field increases instantaneously, the maximum value of the pulsed noise magnetic field intensity can be greater than the second value. Similarly, when a pulsed noise magnetic field is a magnetic field in which the intensity of the applied magnetic field decreases instantaneously, the minimum value of the pulsed noise magnetic field intensity can be less than the first value.

[0082] Furthermore, in this embodiment, particularly during the execution of the closed-loop operation, the control circuit 23 controls the feedback current Icc to make the first detection signal S1 a constant value. Therefore, according to this embodiment, compared to detecting a pulsed noise magnetic field based on a signal that varies according to the object's magnetic field H1, it is easier to detect a pulsed noise magnetic field with low intensity.

[0083] In addition, such as Figure 6 and Figure 7 As shown in the example, the gradient of the change in the first detection signal S1 relative to the change in the intensity of the object magnetic field H1 during the execution of the open-loop action can be smaller than the gradient of the change in the second detection signal S2 relative to the change in the intensity of the object magnetic field H1 during the execution of the closed-loop action. Therefore, it is also easier to detect low-intensity, pulse-like noise magnetic fields.

[0084] In addition, in order to detect the pulsed noise magnetic field, the control circuit 23 may also use a signal obtained by combining the first detection signal S1 and the second detection signal S2, in addition to the first detection signal S1, or it may use a signal obtained by combining the first detection signal S1 and the second detection signal S2 instead of the first detection signal S1.

[0085] Next, the converter device and battery device of this embodiment will be described. Here, the converter device and battery device used in a vehicle that uses an electric motor will be used as examples. Figure 10 This is a block diagram showing the structure of the converter device and the battery device. For example... Figure 10 As shown, an inverter device 102 for controlling the electric motor 101 is connected to the electric motor 101. A battery device 103 is connected to the inverter device 102. The battery device 103 supplies high-voltage power to the electric motor 101 via the inverter device 102. In addition, an ECU (Electronic Control Unit) 104 is connected to the inverter device 102.

[0086] The converter device 102 includes a converter circuit 121 and a magnetic sensor device 1A. The converter circuit 121 includes a conductor through which a current of the target object flows. The magnetic sensor device 1A detects the target current flowing through the conductor of the converter circuit 121 and generates a detection value corresponding to that target current. The structure of the magnetic sensor device 1A is shown in the reference diagram. Figures 1 to 4 The structure of the magnetic sensor device 1 described is the same.

[0087] The battery device 103 includes a power supply circuit 131, a battery 132, and a magnetic sensor device 1B. The power supply circuit 131 includes a conductor for the flow of a current to be detected. The magnetic sensor device 1B detects the current flowing in the conductor of the power supply circuit 131 and generates a detection value corresponding to that current. The structure of the magnetic sensor device 1B is shown in the reference diagram. Figures 1 to 4 The structure of the magnetic sensor device 1 described is the same.

[0088] [Second Implementation]

[0089] Next, the second embodiment of the present invention will be described. Figure 11 This is a cross-sectional view showing the magnetic sensor of the magnetic sensor device of this embodiment. The magnetic sensor device 1 of this embodiment includes a magnetic sensor 110 instead of the magnetic sensor 10 in the first embodiment. The magnetic sensor 110 does not have the shielding member 14 and insulating layer 68 as in the first embodiment. Instead, the magnetic sensor 110 includes an insulating layer 69 disposed on the insulating layer 67. The other structures of the magnetic sensor 110 are the same as those of the magnetic sensor 10 in the first embodiment.

[0090] In this embodiment, the shield 14 is not provided. Therefore, according to this embodiment, the gradient of the change in the first detection signal S1 relative to the changes in the strength of the target magnetic field H1 and the applied magnetic field can be increased. Therefore, according to this embodiment, pulsed noise magnetic fields can be detected more effectively.

[0091] The other structures, functions, and effects in this embodiment are the same as in the first embodiment.

[0092] Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made. For example, the magnetic sensor device of the present invention can also be applied to situations where the magnetic field of the object is not generated by an electric current.

[0093] Based on the above description, it is clear that various methods and variations of the present invention can be implemented. Therefore, within the equivalent scope of the claims, the present invention can be implemented even in ways other than the preferred methods described above.

Claims

1. A magnetic sensor device, characterized in that, include: The first detection circuit includes a magnetic detection element that detects the applied magnetic field and generates a first detection signal that corresponds to the strength of the applied magnetic field. A feedback coil that generates a canceling magnetic field by flowing a feedback current to cancel at least a portion of the magnetic field of the object being detected. The second detection circuit generates a second detection signal that corresponds to the value of the feedback current; and The control circuit controls the feedback current and generates a detection value that corresponds to the strength of the magnetic field of the object. The control circuit is configured to perform a closed-loop operation when the strength of the object's magnetic field is greater than a first value and less than a second value, and to perform an open-loop operation when the strength of the object's magnetic field is less than the first value or greater than the second value. The closed-loop action is the action of the control circuit controlling the feedback current to make the first detection signal a certain value. The open-loop operation is the action taken by the control circuit to maintain the feedback current at a certain value in order to offset part of the magnetic field of the object by eliminating the magnetic field. The control circuit generates the detection value based on the second detection signal when the closed-loop action is executed, and generates the detection value based on the first detection signal when the open-loop action is executed.

2. The magnetic sensor device as described in claim 1, characterized in that, When the control circuit performs the open-loop operation, it maintains the feedback current at a certain value so that the absolute value of the strength of the eliminated magnetic field is equal to the absolute value of the first value or the absolute value of the second value.

3. The magnetic sensor device as described in claim 1, characterized in that, The magnetic detection element is a magnetoresistive element.

4. The magnetic sensor device as described in claim 3, characterized in that, The magnetoresistive element is a tunneling magnetoresistive element.

5. The magnetic sensor device as described in claim 1, characterized in that, The control circuit is configured to detect a pulsed noise magnetic field that overlaps with the applied magnetic field using the first detection signal or a signal obtained by combining the first detection signal and the second detection signal.

6. The magnetic sensor device as described in claim 5, characterized in that, The maximum value of the intensity of the pulsed noise magnetic field is greater than the second value.

7. The magnetic sensor device as described in claim 5, characterized in that, The minimum value of the intensity of the pulsed noise magnetic field is less than the first value.

8. The magnetic sensor device as claimed in claim 1, characterized in that, The gradient of the change in the first detection signal relative to the change in the strength of the object's magnetic field when the open-loop action is performed is different from the gradient of the change in the second detection signal relative to the change in the strength of the object's magnetic field when the closed-loop action is performed.

9. The magnetic sensor device as described in claim 8, characterized in that, The gradient of the change in the first detection signal relative to the change in the strength of the object's magnetic field when the open-loop action is performed is smaller than the gradient of the change in the second detection signal relative to the change in the strength of the object's magnetic field when the closed-loop action is performed.

10. The magnetic sensor device as claimed in claim 1, characterized in that, It also includes a shielding element that concentrates magnetic flux in the vicinity of the magnetic detection element.

11. The magnetic sensor device as claimed in claim 1, characterized in that, The magnetic field of the object is generated by the current flowing through the conductor of the object being detected. The detected value corresponds to the current of the detected object.

12. The magnetic sensor device as claimed in claim 11, characterized in that, The conductor is not provided with a magnetic core that concentrates the magnetic flux generated by the current of the object being detected.

13. A converter device, characterized in that, include: The magnetic sensor device according to claim 11; and A converter circuit that includes the conductor.

14. A battery device, characterized in that, include: The magnetic sensor device according to claim 11; A power supply circuit including the conductor; and The battery connected to the power supply circuit.

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