Magnetic sensor device and magnetic sensor

Abstract

A magnetic sensor device (1) comprises: N (N≥2) magnetic sensor elements (12); N loop-shaped wirings (171) corresponding respectively to the magnetic sensor elements (12); an applying unit (19) that applies an AC current to the N loop-shaped wirings (171); and a self-checking unit (355) that checks for the occurrence of a failure in any of the magnetic sensor elements (12) on the basis of the detection results of each magnetic sensor element (12) when the AC current is applied by the applying unit (19).

Description

Magnetic Sensor Device and Magnetic Sensor

[0001] The present invention relates to a magnetic sensor device and the like.

[0002] Conventionally, a technique for detecting the position of a vehicle by installing magnets (magnetic markers) along a track and detecting them with magnetic sensors (more specifically, a plurality of magnetic sensor elements constituting the magnetic sensors) provided on the vehicle side is known (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2022-170810

[0004] The technique of Patent Document 1 has few failures because, in principle, it does not require power and has a simple structure since it detects the magnetic field generated by the magnet with magnetic sensor elements. However, since the magnetic sensor elements do not emit signals by themselves, there has been a problem that it is difficult to detect a failure when it occurs.

[0005] The problem to be solved by the present invention is to provide a technique capable of investigating the occurrence of failures in magnetic sensor elements.

[0006] The first invention is a magnetic sensor device including: N (N≥2) magnetic sensor elements; N loop-shaped wirings corresponding to each of the magnetic sensor elements; an application unit that applies an alternating current to the N loop-shaped wirings; and an investigation unit that investigates the occurrence of a failure in any of the magnetic sensor elements based on the detection results of each of the magnetic sensor elements when the alternating current is applied by the application unit.

[0007] According to the first invention, N loop-shaped wirings can be arranged corresponding to each of the N magnetic sensor elements, and an alternating current can be applied to each loop-shaped wiring. Then, based on the detection results of each of the magnetic sensor elements when the alternating current is applied, the occurrence of a failure in any of the magnetic sensor elements can be investigated.

[0008] The second invention is the magnetic sensor device according to the above invention, wherein the relative positional relationships of the N loop-shaped wirings with respect to the corresponding magnetic sensor elements are similarly configured.

[0009] According to the second invention, the relative positional relationship of the loop-shaped wiring for each of the N magnetic sensor elements can be configured similarly.

[0010] The third invention is a magnetic sensor device that, in the above invention, further comprises a connecting wire that sequentially connects the N loop-shaped wires, and a connecting wire that connects the N loop-shaped wires in series, wherein the application unit applies the alternating current to the N loop-shaped wires by applying the alternating current to the connecting wire.

[0011] According to the third invention, by arranging connecting wires that sequentially connect N loop-shaped wires in series, and applying an alternating current to the connecting wires, an alternating current can be applied to each loop-shaped wire.

[0012] The fourth invention is a magnetic sensor device in which, in the above invention, the wiring to which the N loop-shaped wirings and the connecting wirings are connected is a single-stroke wiring.

[0013] According to the fourth invention, N loop-shaped wirings and connecting wirings between them can be constructed using a single continuous line of wiring.

[0014] The fifth invention is a magnetic sensor device in which, in the above invention, the connecting wiring consists of a pair of wires arranged next to each other such that the polarity of the current flowing through them is reversed.

[0015] According to the fifth invention, a pair of wires can be placed next to each other so that the polarity of the current flowing through them is reversed, and each loop-shaped wire can be connected in sequence.

[0016] The sixth invention is a magnetic sensor device in which, in the above invention, the alternating current has a frequency between 10 Hz and 10 kHz.

[0017] According to the sixth invention, the frequency of the alternating current is set to a frequency between 10 Hz and 10 kHz.

[0018] The seventh invention is a magnetic sensor device in which, in the above invention, N is 4 or more, and the N magnetic sensor elements are arranged in a planar manner.

[0019] According to the seventh invention, four or more magnetic sensor elements are arranged in a planar configuration.

[0020] The eighth invention is a magnetic sensor device in which, in the above invention, the checking unit checks for the occurrence of a failure in any of the N magnetic sensor elements based on the amplitude and phase of the alternating current based on the detection results of each of the N magnetic sensor elements.

[0021] According to the eighth invention, it is possible to check for the occurrence of a failure in any of the magnetic sensor elements based on the amplitude and phase of the alternating current obtained from the detection results of each of the N magnetic sensor elements.

[0022] The ninth invention is a magnetic sensor in a magnetic sensor device comprising a magnetic sensor and a control device, the magnetic sensor comprising: N (N≧2) magnetic sensor elements; N loop-shaped wiring corresponding to each of the magnetic sensor elements; and an application unit for applying alternating current to the N loop-shaped wiring, wherein the control device can check for the occurrence of a failure in any of the magnetic sensor elements based on the detection result of each of the magnetic sensor elements when the alternating current is applied by the application unit.

[0023] According to the ninth invention, a magnetic sensor capable of achieving the same effects as the first invention can be realized.

[0024] A diagram showing an example of the application of the on-board device. A diagram showing an example of the arrangement of magnetic sensor elements in the magnetic sensor section. A diagram showing an example of the configuration of the magnetic sensor section. A schematic diagram of the wiring section. A diagram showing an example of the calculation results of the amplitude for each magnetic sensor element under normal conditions. A diagram showing an example of the calculation results of the amplitude for each magnetic sensor element when a failure occurs. A diagram showing an example of the calculation results of the phase for each magnetic sensor element under normal conditions. A diagram showing an example of the calculation results of the phase for each magnetic sensor element when a failure occurs. A block diagram to explain an example of the functional configuration of the control device. A flowchart showing the flow of processing performed by the control device.

[0025] Figure 1 is a schematic diagram illustrating an application example of the magnetic sensor device in this embodiment. As shown in Figure 1, the magnetic sensor device 1 is mounted on a railway vehicle 3 that runs on a track 5, and comprises a magnetic sensor unit 10 and a control device 30. Multiple magnets 7 are installed on the track 5 at predetermined positions. For example, the magnets 7 are installed between the left and right rails.

[0026] The magnetic sensor unit 10 is installed on the bottom or bogie of the railway vehicle 3 in a position where it can detect the magnet 7 when passing over the installation location of the magnet 7. Preferably, the magnetic sensor unit 10 is installed in a position where it faces the magnet 7 when passing over the installation location of the magnet 7.

[0027] Figure 2 shows an example of the arrangement of magnetic sensor elements 12 in the magnetic sensor unit 10. As shown in Figure 2, the magnetic sensor unit 10 has N (N≧2) magnetic sensor elements 12 arranged in a planar direction facing the track 5. In the example in Figure 2, the magnetic sensor unit 10 shows a total of four magnetic sensor elements 12 (A) to (D) arranged in a planar direction, two rows in the left-right direction and two rows in the front-rear direction (travel direction) of the railway vehicle 3. The spacing between adjacent magnetic sensor elements 12 is such that they do not overlap, and it is preferable that the distance between the centers of the magnetic sensor elements 12 in both the left-right and front-rear directions is within 150 mm.

[0028] The arrangement of magnetic sensor elements 12 in the magnetic sensor unit 10 is not limited to the example arrangement of 4 elements in total: 2 rows in the left-right direction and 2 rows in the front-back direction (travel direction). For example, an arrangement of 9 elements in 3 rows x 3 columns or 16 elements in 4 rows x 4 columns is also possible. Alternatively, an arrangement of 12 elements in total: 4 rows x 3 columns with different numbers for left-right and front-back is also possible. The arrangement may be set as appropriate. Furthermore, the magnetic sensor unit 10 may be configured with multiple magnetic sensor elements 12 arranged only in the left-right direction.

[0029] The magnetic sensor element 12 is an element that detects a magnetic field and outputs a current or voltage as a detected value corresponding to the magnitude and direction of the magnetic field. In this embodiment, the magnetic sensor element 12 is a three-axis sensor having three detection axes (X-axis, Y-axis, and Z-axis), with the X-axis aligned with the front-to-back direction of the railway vehicle 3, the Y-axis aligned with the left-to-right direction of the railway vehicle 3, and the Z-axis aligned with the up-to-down direction of the railway vehicle 3. For example, the magnetic sensor element 12 is a Hall element, a magnetoresistive element (MR element), a magnetoimpedance element (MI element), a flux-gate sensor, etc. The detected value of the magnetic sensor element 12 is output to the control device 30.

[0030] The control device 30 uses the detection of magnetism by the magnetic sensor unit 10 to determine when the railway vehicle 3 has passed the location where the magnet 7 is installed. In this embodiment, a reference magnetic field distribution is prepared in advance for each type of magnet 7. The reference magnetic field distribution is the reference for the magnetic field distribution detected when passing the location where the corresponding type of magnet 7 is installed. For example, the reference magnetic field distribution can be determined based on the magnetic field distribution detected by the magnetic sensor unit 10 when the railway vehicle 3 actually runs on the track 5 after the magnet 7 has been installed on the track 5. Alternatively, since the magnetic field distribution detected by the magnetic sensor unit 10 is determined by the relative positional relationship between the magnet 7 and the magnetic sensor unit 10, the reference magnetic field distribution can also be determined by experimental results in a laboratory or factory, or by computer simulations.

[0031] While the railway vehicle 3 is in motion, the control device 30 compares the magnetic field distribution detected by the magnetic sensor unit 10 (detected magnetic field distribution) with the reference magnetic field distribution for each type of magnet 7. For example, the control device 30 calculates a correlation coefficient between the detected magnetic field distribution and each reference magnetic field distribution. The correlation coefficient is calculated as a value between "-1" and "1", and a larger absolute value (closer to "1") indicates a stronger correlation (higher similarity), while a smaller absolute value indicates a weaker correlation (lower similarity). The control device 30 determines that a reference magnetic field distribution whose calculated correlation coefficient is equal to or greater than a predetermined threshold (for example, "0.9") is a match with the detected magnetic field distribution. If the control device 30 determines that any of the reference magnetic field distributions is a match, it determines that the vehicle has passed the installation location of a magnet 7 of the type corresponding to that reference magnetic field distribution.

[0032] [Details] The magnetic sensor device 1 of this embodiment has a self-checking function. The self-checking function applies an alternating magnetic field to each of the N magnetic sensor elements 12 and checks for the occurrence of a malfunction by checking whether each magnetic sensor element 12 correctly detects it.

[0033] 1. Regarding the configuration of the magnetic sensor element, Figure 3 is a diagram showing an example of the configuration of the magnetic sensor unit 10 in this embodiment, and is a schematic plan view of the magnetic sensor unit 10 as seen from above. Figure 4 is a schematic diagram showing the wiring unit 17 extracted from Figure 3 and shown transparently. As shown in Figure 3, the magnetic sensor unit 10 of this embodiment comprises a mounting substrate 15, a wiring unit 17 formed on the back surface of the mounting substrate 15, and an application unit 19 for applying an AC current for self-checking to the wiring unit 17. Multiple magnetic sensor elements 12 (A) to (D) are mounted on the mounting substrate 15 (for example, a total of four, in two rows in the left-right direction and two rows in the up-down direction).

[0034] As shown in Figure 4, the wiring section 17 consists of N loop-shaped wirings 171 (171-1 to 171-4) corresponding to each of the N (N=4 in this embodiment) magnetic sensor elements 12, and connecting wirings 173 that sequentially connect the N loop-shaped wirings 171 in series. In this embodiment, the wiring of the wiring section 17, in which the N loop-shaped wirings 171 and the connecting wirings 173 that sequentially connect them are connected, forms a single continuous line of wiring. The arrows shown along the wiring in Figure 4 indicate that it is a single continuous line of wiring. If the mounting substrate 15 is a multilayer substrate, the wiring of the wiring section 17 may be formed in an intermediate layer. It is preferable that the wiring be formed by copper foil patterns on the printed circuit board.

[0035] Here, the control device 30 determines the passage of the location where the magnet 7 is installed by detecting the magnetic field generated by the magnet 7 based on the detection values ​​of each magnetic sensor element 12 while the railway vehicle 3 is in motion. For this reason, it is preferable to separate the detected value of the magnetic field generated by the magnet 7 from the detected value of the self-checking magnetic field generated by the application of the self-checking AC current to each loop-shaped wiring 171. For example, if the detected values ​​of the self-checking magnetic field detected by each magnetic sensor element 12 can be made the same, the same magnetic field will be generated in a biased manner, and the detected value of the self-checking magnetic field can be separated and removed. Furthermore, it is preferable to configure each magnetic sensor element 12 so that, as much as possible, only the magnetic field generated by the corresponding loop-shaped wiring 171 acts on it, out of the magnetic fields that can be generated at various points in the wiring section 17.

[0036] In this embodiment, the N loop-shaped wirings 171 are arranged to surround the corresponding magnetic sensor elements 12 when viewed from above. More specifically, each loop-shaped wiring 171 has the same shape and is sized so that the magnetic sensor elements 12 fit inside the loop when viewed from above. Each loop-shaped wiring 171 is arranged to have a similar relative positional relationship with respect to the corresponding magnetic sensor element 12. In the example shown in Figure 3, each loop-shaped wiring 171 is arranged with its center aligned so that the magnetic sensor element 12 is located in the center of the loop. This ensures that each magnetic sensor element 12 is subjected to a similar biasing magnetic field for self-checking. Furthermore, the connecting wirings 173 that connect each loop-shaped wiring 171 are configured so that a pair of wires are placed next to each other with opposite polarity of the current flowing through them. This reduces the magnetic field generated from the connecting wirings 173 and suppresses its influence on the self-checking magnetic field detected by each magnetic sensor element 12.

[0037] Furthermore, the arrangement of each loop-shaped wiring 171 is not limited to an arrangement where their centers are aligned, as long as the relative positional relationship with respect to the corresponding magnetic sensor element 12 is the same. For example, the arrangement may be such that the centers are offset from each other, as long as the magnetic sensor element 12 is contained within the loop.

[0038] The application unit 19 applies alternating current to the N loop-shaped wirings 171 corresponding to each magnetic sensor element 12 by applying alternating current to the connecting wiring 173. As a result, an alternating magnetic field of the same magnitude acts on each magnetic sensor element 12. The applied alternating current is preferably at a frequency where the phase difference (time difference) in the detection magnetic field of each magnetic sensor element 12 can be ignored, specifically, a frequency where the wavelength is sufficiently long compared to the total length of the connecting wiring 173. In this embodiment, the application unit 19 applies an alternating current with a frequency between 10 Hz and 10 kHz. Note that the waveform of the alternating current does not necessarily have to be a sine wave. A triangular wave or a square wave may also be used.

[0039] 2. Regarding the check for fault occurrence, the control device 30 controls the execution of the self-check function at predetermined timings. For example, this control is performed at timings such as before the start of operation of the railway vehicle 3 or after the end of operation. In this embodiment, the control device 30 controls the application unit 19 to apply alternating current to the N loop-shaped wirings 171 for a predetermined check time. The control device 30 then checks for the occurrence of a fault in any of the magnetic sensor elements 12 based on the detection results of each magnetic sensor element 12 while the alternating current is applied to each loop-shaped wiring 171 by the application unit 19. Specifically, first, the control device 30 calculates the amplitude and phase of the alternating current from the detected value of each magnetic sensor element 12. For each magnetic sensor element 12, the control device 30 performs frequency analysis using a Fast Fourier Transform (FFT) on the time-series data of the detected value of the magnetic sensor element 12 to calculate the amplitude and phase.

[0040] Figure 5 shows an example of the calculation results for the amplitude of each magnetic sensor element 12 under normal conditions, and Figure 6 shows an example of the calculation results for the amplitude of each magnetic sensor element 12 when a failure occurs. Furthermore, Figure 7 shows an example of the calculation results for the phase of each magnetic sensor element 12 under normal conditions, and Figure 8 shows an example of the calculation results for the phase of each magnetic sensor element 12 when a failure occurs.

[0041] As described above, while the application unit 19 is applying alternating current to each loop-shaped wiring 171 (during the verification time), basically, an alternating magnetic field of the same magnitude and the same phase (more precisely, there is a negligible phase difference, so they are approximately the same phase) acts on each magnetic sensor element 12. Therefore, as shown in Figure 5, under normal conditions, the amplitude of the alternating current obtained from the detected value of each magnetic sensor element 12 will all be approximately the same value (approximately 3.5 [μT] in the example of Figure 5). The same applies to the phase, which, as shown in Figure 7, will all be approximately the same value (a value between 70 [°] and 80 [°] in the example of Figure 7).

[0042] On the other hand, if there is a magnetic sensor element 12 whose obtained amplitude and phase show values that are significantly different from those related to other magnetic sensor elements 12, it can be determined that a failure has occurred in that magnetic sensor element 12. In the examples of FIGS. 6 and 8, the values of the amplitude and phase related to the magnetic sensor element 12 in (C) are clearly smaller than those related to other magnetic sensor elements 12.

[0043] Therefore, the control device 30 determines so-called outliers for the calculated amplitude of each magnetic sensor element 12, and similarly determines outliers for the calculated phase of each magnetic sensor element 12. When the control device 30 determines that there is an outlier, it determines that a failure has occurred in the magnetic sensor element 12 related to the outlier. The method for determining outliers is not particularly limited, and known methods such as a method for determining a value that is significantly different from the average value or a method using the interquartile range may be appropriately adopted. In the present embodiment, in order to prevent misjudgment of the occurrence of a failure, when an outlier is continuously determined for a predetermined time for the amplitude or phase related to the same magnetic sensor element 12, it is determined that a failure has occurred in that magnetic sensor element 12. In the examples of FIGS. 6 and 8, it is determined that a failure has occurred in the magnetic sensor element 12 in (C), and a message to that effect is displayed, or notification control is performed such as outputting a warning sound.

[0044] Note that an example of calculating an outlier and determining the occurrence of a failure has been shown. However, a configuration may also be adopted in which threshold ranges that are regarded as normal are determined in advance for each of the amplitude and phase, and when there is a magnetic sensor element 12 whose amplitude or phase shows a value outside the corresponding threshold range, it is determined that a failure has occurred in that magnetic sensor element 12.

[0045] [Functional Configuration] FIG. 9 is a block diagram for explaining an example of the functional configuration of the control device 30. As shown in FIG. 9, the control device 30 constitutes the magnetic sensor device 1 together with the magnetic sensor unit 10. The control device 30 includes an operation unit 310, a display unit 320, a communication unit 330, a processing unit 350, and a storage unit 370, and is configured as a kind of computer system.

[0046] The operation unit 310 is realized by an input device such as a button switch or a touch panel, and outputs an operation signal corresponding to an operation input to the processing unit 350. The display unit 320 is realized by a display device such as an LCD (Liquid Crystal Display) or a touch panel, and performs various displays according to the display signal from the processing unit 350. The communication unit 330 is realized by a wired or wireless communication device, and communicates with a predetermined external device.

[0047] The processing unit 350 is realized by an arithmetic circuit such as a CPU (Central Processing Unit) or a control board including the arithmetic circuit. Based on programs, data, etc. stored in the storage unit 370, it performs various arithmetic processes to control the operation of the magnetic sensor device 1 including the control device 30. In the present embodiment, the processing unit 350 includes a detection unit 351, a determination unit 353, and a self-check unit 355. Each of these functional units may be an arithmetic processing block realized as software by executing a program, or may be a circuit block realized by a signal processing circuit. In the present embodiment, it will be described as an arithmetic processing block realized as software by the processing unit 350 executing a predetermined program.

[0048] During the running of the railway vehicle 3, the detection unit 351 detects the magnetic field distribution (detected magnetic field distribution) at any time based on the detection values of the magnetic sensor elements 12 of the magnetic sensor unit 10.

[0049] The determination unit 353 compares the reference magnetic field distribution that is the reference for the magnetic field distribution detected by the detection unit 351 when passing through the installation position of the magnet 7 with the detected magnetic field distribution detected by the detection unit 351, thereby performing a passing determination of the installation position of the magnet 7 and a type determination of the magnet 7.

[0050] The self-checking unit 355 is a functional unit that performs a self-checking function. At a predetermined timing, it controls the application unit 19 to apply alternating current to each loop-shaped wiring 171 corresponding to each of the N magnetic sensor elements 12 for a predetermined check time. The self-checking unit 355 then checks for the occurrence of a failure in any of the magnetic sensor elements 12 based on the detection results of each magnetic sensor element 12 while the alternating current is applied to each loop-shaped wiring 171 by the application unit 19.

[0051] The storage unit 370 is implemented using a storage medium such as an IC memory or a hard disk. The storage unit 370 pre-stores programs for operating the magnetic sensor device 1, including the control device 30, and for realizing various functions, as well as data used during the execution of said programs, or temporarily stores them each time processing is performed. In this embodiment, the storage unit 370 stores installation magnet data 371, reference magnetic field distribution data 373, detection data 375, and self-check data 377.

[0052] The installation magnet data 371 stores data on the magnets 7 installed on the track 5. For each installation location of the magnets 7, the installation magnet data 371 sets the type of magnet 7 to be installed and the kilometer distance of the installation location. The reference magnetic field distribution data 373 stores reference magnetic field distribution data for each type of magnet 7. The detection data 375 is generated for each detection by the magnetic sensor unit 10 and stores the detected values ​​of each magnetic sensor element 12. The self-check data 377 stores data on the amplitude and phase of the alternating current calculated for each magnetic sensor element 12 based on the detected values ​​of the magnetic sensor elements 12 during the execution of the self-check function, as well as the results of fault determination.

[0053] [Processing Flow] Figure 10 is a flowchart showing the processing flow related to the execution of the self-checking function. In this process, the self-checking unit 355 first controls the application unit 19 to apply alternating current to the connecting wiring 173 for a predetermined checking time, thereby applying alternating current to each loop-shaped wiring 171 corresponding to each of the N magnetic sensor elements 12 (step S1).

[0054] Next, the self-checking unit 355 performs frequency analysis using FFT on the detected values ​​of each magnetic sensor element 12 as needed to calculate the amplitude and phase for each magnetic sensor element 12 (step S3).

[0055] Then, the self-checking unit 355 determines the outliers included in the amplitude of each magnetic sensor element 12 calculated in step S3 (step S5), and determines the outliers included in the phase of each magnetic sensor element 12 calculated in step S3 (step S7). After that, during the check time (step S9: NO), it returns to step S3 and repeats the above process.

[0056] Then, if the verification time has elapsed (step S9: YES), the self-verification unit 355 makes the following determination. Specifically, the self-verification unit 355 refers to the determination result of the amplitude outlier in step S5 and the determination result of the phase outlier in step S7. If there is a magnetic sensor element 12 whose amplitude and / or phase values ​​have been outliers for a predetermined period of time (step S11: YES), it determines that a failure has occurred in the magnetic sensor element 12 (step S13). In that case, the self-verification unit 355 performs control to notify the failure of the magnetic sensor element 12 (step S15).

[0057] As described above, according to this embodiment, N loop-shaped wirings 171 are arranged corresponding to N magnetic sensor elements 12. Next, by applying an alternating current to a connecting wiring 173 that connects each loop-shaped wiring 171 in series, an alternating current can be applied to each loop-shaped wiring 171. Then, from the time-series data of the detected values ​​of each magnetic sensor element 12 while an alternating current is applied to each loop-shaped wiring 171, the amplitude and phase of the alternating magnetic field acting on each magnetic sensor element 12 are calculated. For magnetic sensor elements 12 whose amplitude and / or phase are outliers, it can be determined that a failure has occurred. This makes it possible to realize a method for checking for the occurrence of a failure in any of the magnetic sensor elements 12 in a magnetic sensor device 1 (magnetic sensor unit 10) composed of N (N≧2) magnetic sensor elements 12.

[0058] In the above embodiment, an alternating current is applied to the connecting wiring 173 for a predetermined duration at a predetermined timing, thereby applying an alternating current to the N loop-shaped wirings 171 to check for fault occurrences. Alternatively, the system may be configured to continuously apply an alternating current to each loop-shaped wiring 171 while the railway vehicle 3 is running, thereby checking for fault occurrences.

[0059] As described above, the magnetic field for self-checking acts as a bias on each of the magnetic sensor elements 12. Therefore, while the railway vehicle 3 is running, this bias component can be separated and used for self-checking, and the remaining component can be used to detect the magnetic field generated by the magnet 7.

[0060] 1...Magnetic sensor device 10...Magnetic sensor unit 12...Magnetic sensor element 15...Mounting board 17...Wiring unit 171...Loop-shaped wiring 173...Connection wiring 19...Application unit 30...Control device 350...Processing unit 351...Detection unit 353...Determination unit 355...Self-checking unit 370...Storage unit 371...Installed magnet data 373...Reference magnetic field distribution data 375...Detection data 377...Self-checking data 3...Railway vehicle 5...Track

Claims

1. A magnetic sensor device comprising: N (N≧2) magnetic sensor elements; N loop-shaped wiring corresponding to each of the magnetic sensor elements; an application unit for applying alternating current to the N loop-shaped wiring; and a verification unit for checking for the occurrence of a failure in any of the magnetic sensor elements based on the detection results of each of the magnetic sensor elements when the alternating current is applied by the application unit.

2. The magnetic sensor device according to claim 1, wherein the N loop-shaped wirings are configured in a similar relative positional relationship with respect to the corresponding magnetic sensor elements.

3. A magnetic sensor device according to claim 1 or 2, further comprising a connecting wire that sequentially connects the N loop-shaped wires, the connecting wire that connects the N loop-shaped wires in series, wherein the application unit applies the alternating current to the N loop-shaped wires by applying the alternating current to the connecting wire.

4. The wiring to which the N loop-shaped wirings and the connecting wirings are connected is a single continuous line, as described in claim 3.

5. The magnetic sensor device according to claim 3 or 4, wherein the connecting wiring consists of a pair of wires arranged next to each other such that the polarity of the current flowing through them is reversed.

6. The magnetic sensor device according to any one of claims 3 to 5, wherein the alternating current has a frequency between 10 Hz and 10 kHz.

7. The magnetic sensor device according to any one of claims 1 to 6, wherein N is 4 or more, and the N magnetic sensor elements are arranged in a planar manner.

8. The magnetic sensor device according to any one of claims 1 to 7, wherein the verification unit verifies the occurrence of a failure in any of the magnetic sensor elements based on the amplitude and phase of the alternating current based on the detection results of each of the N magnetic sensor elements.

9. A magnetic sensor in a magnetic sensor device comprising a magnetic sensor and a control device, the magnetic sensor comprising: N (N≧2) magnetic sensor elements; N loop-shaped wiring corresponding to each of the magnetic sensor elements; and an application unit for applying alternating current to the N loop-shaped wiring, wherein the control device is capable of checking for the occurrence of a failure in any of the magnetic sensor elements based on the detection results of each of the magnetic sensor elements when the alternating current is applied by the application unit.

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