Abnormality detecting device and abnormality detecting method

Abstract

To provide an abnormality detecting device and an abnormality detecting method for detecting abnormalities in a circuit using a small number of sensors.SOLUTION: An abnormality detecting system S includes a control device (abnormality detecting device) 1, a battery 10, an inverter circuit 20, and a motor 30. The inverter circuit includes a plurality of switching units 21a to 21f and outputs to the motor by converting a direct current supplied from the battery into an alternating current by switching the plurality of switching units. The switch unit includes a plurality of semiconductor switches and a plurality of magnetic sensors, in which the plurality of magnetic sensors are respectively disposed between the adjacent two semiconductor switches among the plurality of semiconductor switches, and the control device acquires a detection value of the magnetic sensor disposed between the adjacent two semiconductor switches and detects abnormalities in the plurality of semiconductor switches based on the detection value.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to an abnormality detection device and an abnormality detection method. [Background technology]

[0002] Conventionally, in inverter devices and the like, there is a technology for increasing the output current to a load by connecting multiple semiconductor switches in parallel to the load (for example, see Patent Document 1). Patent Document 1 also discloses a technology for preventing an overcurrent from flowing to the remaining semiconductor switches by suppressing the power consumption of the load when some semiconductor switches are stuck off. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-197827 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology, a sensor for detecting an abnormality must be provided for each of the semiconductor switches, which results in a large number of sensors.

[0005] The present application has been made in view of the above, and has an object to provide an abnormality detection device and an abnormality detection method that are capable of detecting an abnormality in a circuit using a small number of sensors. [Means for solving the problem]

[0006] The abnormality detection device of the present application is an abnormality detection device that detects abnormalities in an apparatus that includes a first circuit through which a first current flows, and a second circuit that is arranged adjacent to the first circuit and through which a second current flows, the second current having the same current value as the first current, and determines that an abnormality has occurred when the detection value of a magnetic sensor arranged at an intermediate position between the first circuit and the second circuit is equal to or greater than a reference value. Effect of the Invention

[0007] According to one aspect of the embodiment, an effect is achieved in that a circuit abnormality can be detected with a small number of sensors. [Brief description of the drawings]

[0008] [Figure 1A] FIG. 1A is a diagram illustrating an example of the configuration of an anomaly detection system according to an embodiment. [Figure 1B] FIG. 1B is a diagram illustrating an example of the configuration of the switch unit illustrated in FIG. 1A. [Figure 1C] FIG. 1C is a diagram for explaining an anomaly detection method according to the embodiment. [Figure 1D] FIG. 1D is a diagram for explaining an anomaly detection method according to the embodiment. [Figure 1E] FIG. 1E is a diagram for explaining an anomaly detection method according to the embodiment. [Diagram 2] FIG. 2 is a functional block diagram of the control device. [Diagram 3] FIG. 3 is a flowchart illustrating an example of processing executed by the controller according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an abnormality detection device and an abnormality detection method will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiments.

[0010] First, a configuration example of an anomaly detection system will be described with reference to Fig. 1A and Fig. 1B. Fig. 1A is a diagram showing a configuration example of an anomaly detection system according to an embodiment. Fig. 1B is a diagram showing a configuration example of a switch unit shown in Fig. 1A.

[0011] As shown in FIG. 1A, the abnormality detection system S according to the embodiment includes a control device (abnormality detection device) 1, a battery 10, an inverter circuit 20, and a motor 30. The battery 10 is, for example, a lithium ion battery, and supplies power to the motor 30 via the inverter circuit 20. The inverter circuit 20 includes a plurality of switch units 21a to 21f, and converts a direct current supplied from the battery 10 into an alternating current by switching the plurality of switch units 21a to 21f, and outputs the alternating current to the motor 30. In the following description, the switch units 21a to 21f may be collectively referred to as the switch unit 21 when there is no need to distinguish them from one another. The motor 30 is, for example, a three-phase motor that serves as a power source for a vehicle. The control device 1 performs switching control by supplying a gate voltage to the switch unit 21 included in the inverter circuit 20. The control device 1 also detects an abnormality in the switch unit 21 included in the inverter circuit 20.

[0012] FIG. 1B shows a detailed configuration of the switch unit 21. As shown in FIG. 1B, the switch unit 21 includes a plurality of semiconductor switches 210a, 210b, and 210c, and a plurality of magnetic sensors 211a and 211b. The plurality of semiconductor switches 210a, 210b, and 210c are connected in parallel to the motor 30, which is the output destination. Specifically, the gates (G) of the plurality of semiconductor switches 210a, 210b, and 210c are connected to the control device 1. In the case of the switch units 21a, 21c, and 21e, the sources (S) of the plurality of semiconductor switches 210a, 210b, and 210c are connected to the motor 30, and the drains (D) are connected to the positive electrode of the battery 10. In the case of the switch units 21b, 21d, and 21f, the sources (S) of the plurality of semiconductor switches 210a, 210b, and 210c are connected to the negative electrode side of the battery 10, and the drains (D) are connected to the motor 30. The multiple semiconductor switches 210a, 210b, and 210c are configured as, for example, Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs).

[0013] In this way, by connecting multiple semiconductor switches 210 in parallel, the current of each semiconductor switch 210 can be kept below the rated current, while the sum of the currents of the multiple semiconductor switches 210 can output a current to the motor 30 that is greater than or equal to the rated current.

[0014] The magnetic sensors 211a and 211b are disposed between two adjacent semiconductor switches among the multiple semiconductor switches 210a, 210b, and 210c. Specifically, the magnetic sensor 211a is disposed between the two semiconductor switches 210a and 210b. More specifically, the magnetic sensor 211a is disposed at a position equidistant from each of the two semiconductor switches 210a and 210b. That is, the magnetic sensor 211a is provided at an intermediate position between the semiconductor switch 210a, which is the first circuit, and the semiconductor switch 210b, which is the second circuit. The magnetic sensor 211b is disposed between the two semiconductor switches 210b and 210c. More specifically, the magnetic sensor 211b is disposed at a position equidistant from each of the two semiconductor switches 210b and 210c. That is, the magnetic sensor 211b is provided at an intermediate position between the semiconductor switch 210b, which is the first circuit, and the semiconductor switch 210b, which is the second circuit. In the following description, when the semiconductor switches 210a, 210b, and 210c are not particularly distinguished from each other, they will be collectively referred to as the semiconductor switches 210. When the magnetic sensors 211a and 211b are not particularly distinguished from each other, they will be collectively referred to as the magnetic sensor 211. The abnormality detection device may be a device having a configuration including the magnetic sensor 211, or may be a device having a configuration not including the magnetic sensor 211.

[0015] Here, if any of the multiple semiconductor switches 210 arranged in the switch section 21 becomes abnormal and stuck off, the current that should have flowed through the abnormal semiconductor switch 210 will flow through the other normal semiconductor switches 210. As a result, the current flowing through the normal semiconductor switches 210 will increase and may exceed the rated current. In response to this, in the past, a sensor for detecting an abnormality was provided in each semiconductor switch, and when an abnormality in a semiconductor switch was detected, the current output to the motor was limited. However, in the past, it was necessary to provide the above sensor in each semiconductor switch, which resulted in a large number of sensors.

[0016] Therefore, in the present disclosure, one magnetic sensor 211 is disposed between two adjacent semiconductor switches 210, thereby detecting an abnormality while reducing the number of sensors. Specifically, the control device 1 acquires detection values ​​of the magnetic sensors 211a and 211b disposed between two adjacent semiconductor switches 210, and detects an abnormality in the semiconductor switches 210a, 210b, and 210c based on the detection values. As a result, one magnetic sensor 211 is sufficient for two semiconductor switches 210, and therefore an abnormality in the semiconductor switch 210 can be detected with a small number of sensors. Here, the abnormality detection method in the present disclosure will be described in detail with reference to Figs. 1C to 1E.

[0017] 1C to 1E are diagrams for explaining an abnormality detection method according to an embodiment. FIGS. 1C to 1E show an example of detecting an abnormality in two semiconductor switches 210a and 210b. FIG. 1C shows a case where the two semiconductor switches 210a and 210b are normal, FIG. 1D shows a case where the semiconductor switch 210a is abnormal (stuck in off state), and FIG. 1E shows a case where the semiconductor switch 210b is abnormal (stuck in off state). In FIGS. 1C to 1E, the magnetic sensor 211a is disposed at an equal distance from each of the two semiconductor switches 210a and 210b.

[0018] As shown in FIG. 1C, when the two semiconductor switches 210a and 210b are normal, currents Ca and Cb flow in the same direction at the same current value through the two semiconductor switches 210a and 210b by switching control. As a result, magnetic fields MFa and MFb are generated around the two semiconductor switches 210a and 210b in the direction of right-handed screw rotation with respect to the direction of current flow (right-handed screw rule). The magnetic sensor 211a detects the two magnetic fields MFa and MFb by being disposed at a position where the two magnetic fields MFa and MFb overlap. As shown in FIG. 1C, the currents Ca and Cb flow in the same direction at the same current value, so that the two magnetic fields MFa and MFb cancel each other out at the position (center position) of the magnetic sensor 211a. In other words, the detection value of the magnetic sensor 211a becomes zero (reference value) because the two magnetic fields MFa and MFb cancel each other out. That is, when the detection value of the magnetic sensor 211a is equal to the reference value, the control device 1 determines that the two semiconductor switches 210a and 210b are normal.

[0019] 1D, when the semiconductor switch 210a is stuck off, the current Ca does not flow through the semiconductor switch 210a, and the current Cb flows only through the semiconductor switch 210b. As a result, the magnetic sensor 211a detects the magnetic field MFb generated around the semiconductor switch 210b. In other words, the magnetic field MFb remains without being canceled out, so the detection value of the magnetic sensor 211a is a value other than zero (reference value). Specifically, the detection value of the magnetic sensor 211a is a value equal to or greater than zero.

[0020] 1E, when semiconductor switch 210b is stuck off, current Cb does not flow through semiconductor switch 210b, and current Ca flows only through semiconductor switch 210a. As a result, magnetic sensor 211a detects magnetic field MFa generated around semiconductor switch 210a. In other words, since magnetic field MFa remains without being canceled out, the detection value of magnetic sensor 211a is a value other than zero (reference value). Specifically, the detection value of magnetic sensor 211a is a value equal to or greater than zero.

[0021] 1D and 1E, when the detection value of the magnetic sensor 211a deviates from the reference value, the control device 1 determines that one of the two semiconductor switches 210a, 210b is abnormal. Specifically, when the detection value of the magnetic sensor 211a is equal to or greater than zero (reference value), the control device 1 determines that one of the two semiconductor switches 210a, 210b is abnormal.

[0022] In this manner, the control device 1 according to the embodiment can detect that either of the two semiconductor switches 210a, 210b is abnormal from the detection value of the single magnetic sensor 211a. Therefore, while two sensors were conventionally required for two semiconductor switches, in the present disclosure, one magnetic sensor 211 is sufficient for the two semiconductor switches 210, and therefore an abnormality in the semiconductor switch 210 can be detected with a smaller number of sensors. Furthermore, by reducing the number of sensors, the cost of the product (inverter circuit 20) can be reduced.

[0023] 1D and 1E, the magnetic fields MFa and MFb at the position of the magnetic sensor 211a have different magnetic field directions. Specifically, at the position of the magnetic sensor 211a, the magnetic field MFa is oriented toward the front side of the paper, whereas the magnetic field MFb is oriented toward the back side of the paper. In consideration of this point, the control device 1 acquires the magnetic field direction detected by the magnetic sensor 211a, and identifies which of the two semiconductor switches 210a and 210b is abnormal based on the acquired magnetic field direction. Specifically, the control device 1 uses the magnetic sensor 211 whose detection value differs depending on the magnetic field direction (for example, the detection value is positive or negative), and identifies the abnormal semiconductor switch 210 based on the detection value of the magnetic sensor 211. This makes it possible to identify the abnormal semiconductor switch 210 with a small number of sensors.

[0024] Next, when the control device 1 detects an abnormality in the semiconductor switch 210, it reduces the command value of the current to be output to the motor 30 (hereinafter, the current command value). Then, the control device 1 inputs a gate voltage based on the reduced current command value to the inverter circuit 20. This makes it possible to reduce the risk of an overcurrent flowing through a normal semiconductor switch 210 and causing a breakdown, even if an abnormality occurs in the semiconductor switch 210.

[0025] In addition, although FIG. 1B shows an example in which the magnetic sensor 211 is disposed at a position equidistant from each of the two semiconductor switches 210, the magnetic sensor 211 may be disposed at a position closer to either of the two semiconductor switches 210. In this case, the influence of the magnetic field MF of the closer semiconductor switch 210 becomes stronger, so that the reference value of the magnetic sensor 211 becomes a predetermined value other than zero. In this case, the reference value is set based on, for example, the distance from the magnetic sensor 211 to each of the two semiconductor switches 210. Alternatively, the control device 1 may obtain detection values ​​when the two semiconductor switches 210 are not abnormal and set them as the reference values. This allows the reference value to be set according to the actually measured detection values, thereby improving the accuracy of the abnormality determination of the semiconductor switch 210.

[0026] In the above description, it is assumed that the currents flowing through the two semiconductor switches 210 are in the same direction, but this is not limiting. For example, the currents flowing through the two semiconductor switches 210 may be in opposite directions. In this case, the magnetic fields MF generated in the two semiconductor switches 210 are in opposite directions, and the reference value of the magnetic sensor 211 is the sum of the two magnetic fields MF.

[0027] In the above, it is assumed that the currents flowing through the two semiconductor switches 210 have the same current value, but the current values ​​may be different. In this case, the strength of the magnetic field MF generated in each of the two semiconductor switches 210 is different, and therefore the reference value of the magnetic sensor 211 is a value according to the difference in strength of the magnetic field MF. In this case, the reference value may be set to a value estimated based on the current values ​​flowing through the two semiconductor switches 210, or a detection value when the two semiconductor switches 210 are not abnormal may be acquired and set as the reference value.

[0028] In addition, in FIG. 1A, the control device 1 is an abnormality detection device, but the control device that controls the inverter circuit 20 and the abnormality detection device that detects an abnormality in the semiconductor switch 210 may be configured separately.

[0029] Next, a configuration example of the control device 1 according to the embodiment will be described with reference to Fig. 2. Fig. 2 is a functional block diagram of the control device 1. As shown in Fig. 2, the control device 1 according to the embodiment includes a controller 2 and a storage unit 3.

[0030] The controller 2 includes a computer and various circuits having, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a hard disk drive, an input / output port, etc. The CPU of the computer functions by, for example, reading and executing a program stored in the ROM or the storage unit 3.

[0031] The storage unit 3 includes a non-volatile storage medium such as a non-volatile memory, a flash memory, a hard disk drive, etc. The storage unit 3 stores, for example, information on the above-mentioned reference values, etc.

[0032] Next, the operation of the controller 2 will be described.

[0033] The controller 2 inputs a gate voltage to the inverter circuit 20 to perform switching control. The controller 2 also acquires a detection value of the magnetic sensor 211 during a period in which the controller 2 performs switching control. The controller 2 also determines whether or not the detection value of the magnetic sensor 211 deviates from a reference value. For example, if the detection value of the magnetic sensor 211 does not deviate from a reference value (detection value=reference value), the controller 2 determines that the two semiconductor switches 210 on both sides of the magnetic sensor 211 are normal. If the detection value of the magnetic sensor 211 deviates from a reference value (detection value≠reference value), the controller 2 also determines that one of the two semiconductor switches 210 on both sides of the magnetic sensor 211 is abnormal. If the detection value of the magnetic sensor 211 deviates from a reference value, the controller 2 acquires information on the direction of the magnetic field detected by the magnetic sensor 211, and identifies which semiconductor switch 210 is abnormal based on the direction of the magnetic field.

[0034] When it is determined that the semiconductor switch 210 is abnormal, the controller 2 reduces the command value of the current to be output to the motor 30, and inputs a gate voltage based on the reduced command value to the inverter circuit 20. This makes it possible to prevent an overcurrent from flowing to the semiconductor switches 210 other than the semiconductor switch 210 determined to be abnormal.

[0035] Next, a process executed by the controller 2 according to the embodiment will be described with reference to Fig. 3. Fig. 3 is a flowchart showing an example of the process executed by the controller 2 according to the embodiment. The process shown in Fig. 3 is repeatedly executed from when the vehicle power is turned on (the ignition key is turned on) until it is turned off.

[0036] 3, the controller 2 inputs a gate voltage to the inverter circuit 20 (step S101). Next, the controller 2 acquires a detection value of the magnetic sensor 211 (step S102).

[0037] Next, the controller 2 determines whether the acquired detection value is a reference value (step S103). If the detection value is the reference value (step S103: Yes), the controller 2 determines that the semiconductor switch 210 is normal (no abnormality) (step S104) and ends the process.

[0038] On the other hand, in step S103, if the detection value is outside the reference value (step S103: No), the controller 2 determines that one of the two semiconductor switches 210 on either side of the magnetic sensor 211 is abnormal (step S105).

[0039] Next, the controller 2 acquires information on the direction of the magnetic field from the magnetic sensor 211 (step S106). Next, the controller 2 identifies the abnormal semiconductor switch 210 based on the direction of the magnetic field (step S107).

[0040] Next, the controller 2 reduces the current command value to be output to the motor 30 (step S108), and inputs a gate voltage based on the reduced current command value to the inverter circuit 20, thereby completing the process.

[0041] As described above, the control device (abnormality detection device) 1 according to the embodiment is an abnormality detection device that detects abnormalities in an apparatus including a first circuit (semiconductor switch) through which a first current flows, and a second circuit (semiconductor switch) that is provided adjacent to the first circuit and through which a second current flows that has the same current value as the first current, and that determines that an abnormality has occurred when the detection value of the magnetic sensor 211 provided at an intermediate position between the first circuit and the second circuit is equal to or greater than a reference value.

[0042] As a result, abnormalities in two semiconductor switches 210 can be detected from the detection value of one magnetic sensor 211, making it possible to detect abnormalities in the semiconductor switches with a smaller number of sensors than in the conventional case where a sensor is provided for each semiconductor switch to detect abnormalities.

[0043] In the above-described embodiment, an example of detecting an abnormality in two semiconductor switches 210 has been described, but the abnormality can be detected in any circuit, not limited to the semiconductor switches 210, as long as it is a circuit in a path through which a current flows.

[0044] In the above-described embodiment, an example is shown in which an abnormality is detected in two semiconductor switches 210 connected in parallel in the inverter circuit 20, but the embodiment is not limited to this. For example, one magnetic sensor 211 may be disposed between two circuits provided in different devices to detect an abnormality in the two circuits.

[0045] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0046] 1 Control device (abnormality detection device) 2. Controller 3 Storage section 10 batteries 20 Inverter circuit 21 Switch section 30 Motor 210 Semiconductor Switch 211 Magnetic Sensor

Claims

1. 1. An abnormality detection device for detecting an abnormality in a device including a first circuit through which a first current flows, and a second circuit provided adjacent to the first circuit and through which a second current flows, the second current having the same current value as the first current, determining that an abnormality has occurred when a detection value of a magnetic sensor provided at an intermediate position between the first circuit and the second circuit is equal to or greater than a reference value; Anomaly detection device.

2. The first circuit and the second circuit are connected in parallel to an output destination. The abnormality detection device according to claim 1 .

3. the magnetic sensor is disposed at a position equidistant from the first circuit and the second circuit, The reference value is zero, When the detected value is a value other than zero, it is determined that either the first circuit or the second circuit is abnormal. The abnormality detection device according to claim 1 .

4. The detection value when the first circuit and the second circuit are not abnormal is set as the reference value. The abnormality detection device according to claim 1 .

5. The first circuit and the second circuit are A semiconductor switch is provided in the inverter, which is the device. The abnormality detection device according to claim 1 .

6. When the detected value deviates from a reference value, information on the direction of the magnetic field detected by the magnetic sensor is acquired, and it is determined whether the first circuit or the second circuit is abnormal based on the acquired direction of the magnetic field. The abnormality detection device according to claim 1 .

7. a first circuit through which a first current flows; a second circuit provided adjacent to the first circuit and through which a second current having the same current value as the first current flows; a magnetic sensor provided at an intermediate position between the first circuit and the second circuit; a control unit that acquires a detection value of the magnetic sensor and determines that an abnormality has occurred when the detection value is equal to or greater than a reference value; An abnormality detection device comprising:

8. 1. An abnormality detection method performed by a controller that detects an abnormality in an apparatus including a first circuit through which a first current flows and a second circuit that is provided adjacent to the first circuit and through which a second current flows, the second current having the same current value as the first current, the method comprising: determining that an abnormality has occurred when a detection value of a magnetic sensor provided at an intermediate position between the first circuit and the second circuit is equal to or greater than a reference value; Anomaly detection methods.

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