Interlock device

Abstract

To provide an interlock device having higher safety.SOLUTION: The description herein discloses an interlock device configured to detect attachment of an attachable / detachable component to be attached to and detached from a high-voltage device. The interlock device includes a first circuit provided in the high-voltage device and a second circuit provided in the attachable / detachable component. The first circuit includes a pair of first terminals, a power supply circuit configured to apply a reference voltage to the pair of first terminals via a first resistor, and a processing device configured to monitor a voltage between the pair of first terminals. The second circuit includes a pair of second terminals and a connection circuit that electrically connects the pair of second terminals via a second resistor. When the attachable / detachable component is attached to the high-voltage device, the pair of first terminals and the pair of second terminals are connected to each other, and the processing device determines that the attachable / detachable component is attached when a voltage between the pair of first terminals is within a predetermined range. Here, the lower limit value of the predetermined range is larger than zero, and the upper limit value is smaller than the reference voltage.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to an interlock device. [Background technology]

[0002] Patent Document 1 discloses an interlock device for detecting disconnection of a connector that connects high-voltage equipment to a high-voltage power supply. This interlock device detects connection or disconnection of the connector, a short circuit in the power supply, a short circuit in the ground, etc. based on the combination of an output signal (H or L) output from a controller and an input signal (H or L) input to the controller. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-145848 Summary of the Invention [Problem to be solved by the invention]

[0004] Typically, in an interlock device, if a removable part is not attached to a high-voltage device, the supply of high voltage to the high-voltage device is cut off. However, even if a removable part is not attached to the high-voltage device, a short circuit may occur between the first terminals due to the influence of a foreign object or the like, and the processing device may mistakenly believe that a removable part is attached to the high-voltage device. It is undesirable for high voltage to be supplied to the high-voltage device in such a state. The technology of Patent Document 1 does not take such a state into consideration. This specification provides an interlock device with higher safety. [Means for solving the problem]

[0005] This specification discloses an interlock device that detects the attachment of a removable component that is attached to or detached from a high-voltage device. The interlock device includes a first circuit provided in the high-voltage device and a second circuit provided in the removable component. The first circuit has a pair of first terminals, a power supply circuit that applies a reference voltage to the pair of first terminals via a first resistor, and a processing device that monitors the voltage between the pair of first terminals. The second circuit has a pair of second terminals and a connection circuit that electrically connects the pair of second terminals via a second resistor. When the removable component is attached to the high-voltage device, the pair of first terminals and the pair of electrical terminals are connected to each other. The processing device determines that the removable component is attached when the voltage between the pair of first terminals is within a predetermined range. Here, the lower limit of the predetermined range is greater than zero and the upper limit of the predetermined range is less than the reference voltage.

[0006] According to the above configuration, when the removable component is attached to the high-voltage device, the first circuit provided in the high-voltage device and the second circuit provided in the removable component are electrically connected. As a result, the first resistor and the second resistor are connected in series to the power supply circuit, and the voltage between the pair of first terminals is a voltage corresponding to the resistance ratio of the first resistor to the second resistor. This voltage is significantly greater than zero volts but significantly smaller than the reference voltage.

[0007] On the other hand, when no removable part is attached to the high-voltage device, the pair of first terminals is usually electrically open. As a result, the voltage between the pair of first terminals is approximately equal to the reference voltage of the power supply circuit. However, it is also possible that a conductive foreign object may come into contact with the pair of first terminals when no removable part is attached to the high-voltage device. In this case, the pair of first terminals is electrically shorted, and the voltage between the pair of first terminals is approximately zero volts.

[0008] As described above, in the above configuration, the processing device monitors the voltage between the pair of first terminals and determines that a removable component is attached when the voltage is within a predetermined range. The lower limit of the predetermined range is greater than zero, and the upper limit of the predetermined range is less than the reference voltage. This configuration makes it possible to accurately determine whether a removable component is attached. In particular, even if a short circuit occurs between the pair of first terminals due to a foreign object or the like when no removable component is attached, it is possible to avoid misidentifying this as the attachment of a removable component. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic diagram of an interlock device. [Figure 2] 10 is a flowchart of a process executed by a microcomputer. [Figure 3] 10A and 10B are diagrams for explaining a process executed by a microcomputer in accordance with a recognized voltage. DETAILED DESCRIPTION OF THE INVENTION

[0010] An interlock device 2 according to an embodiment will be described with reference to the drawings. The interlock device 2 detects the attachment of a connector 20 that is attached to or detached from a high voltage device 10 that is supplied with a high voltage, such as an inverter. The interlock device 2 is mounted on, for example, an electric vehicle.

[0011] High-voltage device 10 is provided with a first circuit 12. First circuit 12 includes a pair of first terminals 14, 14, a power supply circuit 16, a first resistor 18, a microcomputer 19, and ground 30. One of the pair of first terminals 14 is provided on the power supply circuit 16 side, and the other of the pair of first terminals 14 is provided on the ground 30 side. Power supply circuit 16 applies a reference voltage V1 to the pair of first terminals 14, 14 via first resistor 18. First resistor 18 has a resistance value R1. Microcomputer 19 monitors the voltage between the pair of first terminals 14, 14. Hereinafter, the voltage monitored by microcomputer 19 will be referred to as the "recognized voltage."

[0012] The connector 20 is provided with a second circuit 22. The second circuit 22 includes a pair of second terminals 24, 24, a second resistor 26, and a connection circuit 28. One of the pair of second terminals 24 is configured to connect to one of the pair of first terminals 14, and the other of the pair of second terminals 24 is configured to connect to the other of the pair of first terminals 14. The second resistor 26 has a resistance value R2. The resistance value R2 may be the same as or different from the resistance value R1. The connection circuit 28 electrically connects the pair of second terminals 24, 24 via the second resistor 26.

[0013] When the connector 20 is attached to the high-voltage device 10, the pair of first terminals 14, 14 of the first circuit 12 and the pair of second terminals 24, 24 of the second circuit 22 are connected to each other.

[0014] Next, the processing executed by the microcomputer 19 will be described with reference to Fig. 2. The microcomputer 19 executes the processing in Fig. 2 while the microcomputer 19 is activated (for example, while the switch of the electric vehicle on which the interlock device 2 is installed is on).

[0015] In S10, the microcomputer 19 determines whether the recognized voltage is smaller than a first threshold value Th1. Here, the first threshold value Th1 is set to a value smaller than the reference voltage V1. As will be described in detail later, the first threshold value Th1 may be a value determined based on the reference voltage V1 and the resistance values ​​R1 and R2. If the recognized voltage is smaller than the first threshold value Th1 (YES in S10), the microcomputer 19 proceeds to S30, and if the recognized voltage is greater than the first threshold value Th1 (NO in S10), the microcomputer 19 proceeds to S20.

[0016] Now, let us consider a situation in which connector 20 is not attached to high-voltage device 10. In this case, the pair of first terminals 14, 14 is normally electrically disconnected. As a result, the voltage between the pair of first terminals 14, 14 (i.e., the recognized voltage) becomes approximately equal to reference voltage V1 from power supply circuit 16. Here, first threshold value Th1 is set to a value smaller than reference voltage V1, so microcomputer 19 determines that the recognized voltage is greater than first threshold value Th1 (NO in S10). In other words, when connector 20 is not attached to high-voltage device 10, the determination in S10 is NO.

[0017] In S20, microcomputer 19 determines that connector 20 is not attached to high voltage device 10, and cuts off the application of high voltage to high voltage device 10.

[0018] In S30, the microcomputer 19 determines whether the recognized voltage is greater than a second threshold value Th2. Here, the second threshold value Th2 is set to a value greater than zero. As will be described in detail later, the second threshold value Th2 may also be a value determined based on the reference voltage V1 and the resistance values ​​R1 and R2. If the recognized voltage is greater than the second threshold value Th2 (YES in S30), the microcomputer 19 proceeds to S40, and if the recognized voltage is greater than the second threshold value Th2 (NO in S30), the microcomputer 19 proceeds to S50.

[0019] Assume now that the connector 20 is attached to the high-voltage device 10. In this case, the pair of first terminals 14, 14 and the pair of second terminals 24, 24 are connected to each other. This electrically connects the first circuit 12 provided in the high-voltage device 10 to the second circuit 22 provided in the connector 20. As a result, the first resistor 18 and the second resistor 26 are connected in series to the power supply circuit 16. In this case, the voltage between the pair of first terminals 14, 14 (i.e., the recognized voltage) is a voltage that corresponds to the resistance ratio between the first resistor 18 and the second resistor 26. Specifically, the voltage between the pair of first terminals 14, 14 is the reference voltage V1 from the power supply circuit 16 minus the voltage drop caused by the current flowing through the first resistor 18. The combined resistance of the circuit in which the first resistor 18 and the second resistor 26 are connected in series is (R1 + R2), so the current I flowing through the circuit is I = V1 / (R1 + R2). Therefore, the voltage drop across the first resistor 18 is R1·I=V1·(R1 / (R1+R2)). Therefore, the recognized voltage is V1-(V1·(R1 / (R1+R2)))=V1·(R2 / (R1+R2)). Here, the thresholds Th1 and Th2 are set so that the recognized voltage V1·(R2 / (R1+R2)) is smaller than the first threshold Th1 and larger than the second threshold Th2. Therefore, the microcomputer 19 determines that the recognized voltage is smaller than the first threshold Th1 and larger than the second threshold Th2 (YES in S30). That is, when the connector 20 is attached to the high-voltage device 10, the determination in S30 is YES.

[0020] In S40, the microcomputer 19 determines that the connector 20 is attached to the high voltage device 10, and allows the application of high voltage to the high voltage device 10.

[0021] Furthermore, assume a situation in which a conductive foreign object or the like comes into contact with the first terminals 14, 14, thereby causing an electrical short circuit between the pair of first terminals 14, 14. In this case, the pair of first terminals 14, 14 and the pair of second terminals 24, 24 are not connected to each other, but the pair of first terminals 14, 14 are electrically short-circuited, so the voltage between the pair of first terminals 14, 14 (i.e., the recognized voltage) is approximately zero volts. Here, because the second threshold value Th2 is set to a value greater than zero, the microcomputer 19 determines that the recognized voltage is smaller than the second threshold value Th2 (NO in S30). In other words, if a short circuit occurs between the pair of first terminals 14, 14 due to the influence of a foreign object or the like even though the connector 20 is not attached to the high-voltage device 10, a NO determination is made in S30.

[0022] In S50, microcomputer 19 determines that connector 20 is not attached to high voltage device 10, and cuts off the application of high voltage to high voltage device 10.

[0023] The above can be summarized as shown in Figure 3. That is, as shown in Figure 3, when the recognized voltage is smaller than first threshold value Th1 and larger than second threshold value Th2 (YES in S10 and YES in S30 in Figure 2), microcomputer 19 determines that connector 20 is attached to high-voltage device 10 (S40). In this case, microcomputer 19 allows the application of high voltage to high-voltage device 10.

[0024] On the other hand, if the recognized voltage is greater than the first threshold value Th1 (NO in S10) or less than the second threshold value Th2 (NO in S30), microcomputer 19 determines that connector 20 is not attached to high-voltage device 10 (S20, S30). In this case, microcomputer 19 does not allow the application of high voltage to high-voltage device 10.

[0025] As described above, according to this embodiment, the microcomputer 19 monitors the voltage between the pair of first terminals 14, 14 (i.e., the recognized voltage), and determines that the connector 20 is attached when the recognized voltage is smaller than the first threshold value Th1 and larger than the second threshold value Th2. The first threshold value Th1 is smaller than the reference voltage V1, and the second threshold value Th2 is larger than zero. According to the configuration of this embodiment, the microcomputer 19 can correctly determine whether or not the connector 20 is attached. In particular, even if the pair of first terminals 14, 14 is short-circuited by a foreign object or the like when the connector 20 is not attached, it is possible to avoid mistaking this as the attachment of the connector 20.

[0026] The following points should be noted regarding the above embodiment. The connector 20 is an example of a "detachable part" of the present technology. The microcomputer 19 is an example of a "processing device" of the present technology. The first threshold value Th1 and the second threshold value Th2 are examples of an "upper limit value" and a "lower limit value" of the present technology, respectively. [Explanation of symbols]

[0027] 2: Interlock device, 10: High voltage device, 12: First circuit, 14: Power supply circuit, 16, 24: Resistor, 18: Microcomputer, 19: First terminal, 20: Detachable part, 22: Second circuit, 26: Second terminal

Claims

[Claim 1] An interlock device for detecting the attachment of a detachable part attached to or detached from a high-voltage device, a first circuit provided in the high-voltage device; a second circuit provided in the detachable part, the first circuit includes a pair of first terminals, a power supply circuit that applies a reference voltage to the pair of first terminals via a first resistor, and a processing device that monitors a voltage between the pair of first terminals; the second circuit has a pair of second terminals and a connection circuit that electrically connects the pair of second terminals via a second resistor; When the detachable part is attached to the high-voltage device, the pair of first terminals and the pair of second terminals are connected to each other, the processing device determines that the removable component is attached when the voltage between the pair of first terminals is within a predetermined range; the lower limit of the predetermined range is greater than zero, and the upper limit of the predetermined range is less than the reference voltage; Interlock device.

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