Discharge device

Abstract

To provide a discharge device capable of performing discharge treatment even if a fault occurs in a control part.SOLUTION: A discharge device includes: a discharge circuit which performs discharge of electric charge accumulated in a smoothing capacitor; a control part which issues an instruction of the discharge to the discharge circuit; and an interface circuit which issues an instruction of the discharge to the discharge circuit when the control part cannot issue the instruction of the discharge.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a discharge device.

Background Art

[0002] In order to remove voltage ripples associated with the switching operation of an inverter mounted on a vehicle, a smoothing capacitor is connected in parallel to the inverter (see, for example, Patent Document 1).

[0003] When it is determined that the vehicle system requires it, discharge of the smoothing capacitor by a discharge device (hereinafter referred to as "discharge processing") is performed. Specifically, the discharge device has a discharge circuit and a control unit. The discharge circuit discharges the charge stored in the smoothing capacitor. The control unit causes the discharge circuit to perform discharge processing by giving a discharge instruction to the discharge circuit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when an abnormality occurs in the control unit, there may be a case where the control unit cannot give a discharge instruction to the discharge circuit. As a result, even when discharge processing is necessary, if an abnormality occurs in the control unit, the discharge processing may not be executed.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a discharge device capable of executing discharge processing even when an abnormality occurs in the control unit.

Means for Solving the Problems

[0007] (1) One aspect of the present invention is a discharge device including a discharge circuit that discharges the charge stored in a smoothing capacitor, a control unit that gives an instruction to the discharge circuit to perform the discharge, and an interface circuit that gives an instruction to the discharge circuit to perform the discharge when the control unit is unable to give the instruction to the discharge circuit.

[0008] (2) In the discharge device according to (1) above, when the control unit is operating normally, it outputs a specific signal to the interface circuit, and when an abnormality occurs in which the instruction to perform the discharge cannot be given, the output of the specific signal is stopped. The interface circuit may give an instruction to the discharge circuit to perform the discharge when the specific signal disappears.

[0009] (3) In the discharge device according to (1) or (2) above, the discharge circuit includes a discharge switch for discharging the charge stored in the smoothing capacitor. When the discharge switch is controlled from the off state to the on state, the discharge is executed. The interface circuit may control the discharge switch to the on state by the charge of the smoothing capacitor when the control unit is unable to give an instruction to perform the discharge.

[0010] (4) In the discharge device according to (3) above, a delay circuit may be provided to delay the timing at which the discharge switch becomes on so that the discharge switch becomes on after the startup of the control unit is completed.

Advantages of the Invention

[0011] As described above, according to the present invention, even when an abnormality occurs in the control unit, a discharge device capable of executing a discharge process can be provided.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution means of the invention. In the drawings, the same or similar parts may be denoted by the same reference numerals, and redundant descriptions may be omitted. Also, the shapes and sizes of the elements in the drawings may be exaggerated for clearer explanation.

[0014] The "connection" described below refers to an electrical connection. An electrical connection means that electrical signals are connected so as to be directly or indirectly transmissible. The electrical connection may be a connection via components such as cables, resistors, capacitors, diodes, and switches.

[0015] FIG. 1 is a diagram showing an example of the schematic configuration of a vehicle system 100 including a discharge device according to the present embodiment. The vehicle system 100 is mounted on a vehicle such as a hybrid vehicle or an electric vehicle. This vehicle is, for example, an electric vehicle having a motor as a driving power source.

[0016] As shown in FIG. 1, the vehicle system 100 includes a battery 110, a first contactor 120, a second contactor 130, a motor 140, a power conversion device 150, a smoothing capacitor 160, and a discharge device 170.

[0017] The battery 110 is mounted on the vehicle system 100 and is a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. For example, the power of the battery 110 is used as the driving power of the motor 140 or the operating power of devices mounted on the vehicle system 100. The battery 110 may be an all-solid-state battery. The battery 110 may include a plurality of battery cells connected in series.

[0018] The first contactor 120 is an energization switch having a pair of contacts. The first contactor 120 has the first contact connected to the positive terminal of the battery 110 and the second contact connected to the power conversion device 150. The first contactor 120 is controlled to be in a closed state or an open state according to the control from a battery ECU (not shown) mounted on the vehicle. When the first contactor 120 is controlled to be in the closed state, the positive terminal of the battery 110 and the first input terminal of the power conversion device 150 are electrically connected. When the second contactor 130 is controlled to be in the open state, the electrical connection between the positive terminal of the battery 110 and the first input terminal of the power conversion device 150 is released.

[0019] The second contactor 130 is a power-on / off switch having a pair of contacts. In the second contactor 130, the first contact is connected to the negative terminal of the battery 110, and the second contact is connected to the second input terminal of the power conversion device 150. The second contactor 130 is controlled to be in a closed state or an open state according to the control from the battery ECU. When the second contactor 130 is controlled to be in the closed state, the negative terminal of the battery 110 and the second input terminal of the power conversion device 150 are electrically connected. When the second contactor 130 is controlled to be in the open state, the electrical connection between the negative terminal of the battery 110 and the second input terminal of the power conversion device 150 is released.

[0020] The motor 140 is an electric motor driven by the power from the power conversion device 150. For example, the motor 140 is a driving motor for a vehicle on which the vehicle system 100 is mounted. For example, the motor 140 is a three-phase (U, V, W) brushless motor. Note that the motor 140 may be a motor generator. The motor 140 may be used as a generator driven by the vehicle engine and also as an electric motor for starting the engine. For example, the motor 140 mainly operates as an electric motor to drive the vehicle wheels. However, it is not limited thereto, and the motor 140 is not particularly limited as long as it is an electric motor mounted on the vehicle.

[0021] The power conversion device 150 converts the DC power from the battery 110 into predetermined AC power and supplies it to the motor 140. In the case of the regenerative operation of the motor 140, the power conversion device 150 may convert the regenerative power supplied from the motor 140 from AC to DC and supply it to the battery 110. The power conversion device 150 includes an inverter and may further include a DC-DC converter.

[0022] For example, the power conversion device 150 may boost the output voltage VBAT output from the battery 110 and convert the boosted voltage into alternating current. Then, the power conversion device 150 drives the motor 140 by outputting the converted alternating current voltage to the motor 140. Note that the power conversion device 150 may have a function of stepping down the regenerative voltage from the motor 140 at a predetermined step-down ratio and outputting it to the battery 110.

[0023] The smoothing capacitor 160 is connected in parallel to the power conversion device 150. For example, the smoothing capacitor 160 is connected in parallel to the inverter to remove voltage ripples associated with the switching operation. One end of the smoothing capacitor 160 is connected between the plus terminal of the battery 110 and the power conversion device 150, and the other end is connected between the minus terminal of the battery 110 and the power conversion device 150. Note that the connection position of the smoothing capacitor 160 is not particularly limited as long as it is connected in parallel to the power conversion device 150.

[0024] The discharge device 170 is a device that discharges the charge of the smoothing capacitor 160. For example, the discharge device 170 includes a discharge circuit 210, a control unit 220, and an interface circuit 230. FIG. 2 is an example of the circuit configuration of the discharge device 170 according to the present embodiment.

[0025] The discharge circuit 210 discharges the charge stored in the smoothing capacitor 160. For example, as shown in FIG. 2, the discharge circuit 210 includes a discharge resistor 310, a discharge switch 320, an open / close switch 330, and a delay circuit 340.

[0026] One end of the discharge resistor 310 is connected to one end of the smoothing capacitor 160 via the open / close switch 330, and the other end is connected to the ground (GND) via the discharge switch 320. The discharge resistor 310 may be a single resistor or a plurality of resistors.

[0027] The discharge switch 320 is a switch for discharging the charge stored in the smoothing capacitor 160. In the present embodiment, the discharge switch 320 is connected between the discharge resistor 310 and the ground. When the discharge switch 320 is controlled from the off state to the on state, the discharge of the smoothing capacitor 160 is executed on the condition that the open / close switch 330 is in the on state. The discharge switch 320 may be an electrical switch such as a transistor (including a non-contact relay), or a mechanical switch such as a contact relay. Note that In FIG. 2, the case where the discharge switch 320 is a transistor is described as an example.

[0028] One end of the open / close switch 330 is connected to one end of the smoothing capacitor 160, and the other end is connected to one end of the discharge resistor 310. When the open / close switch is in the on state, one end of the smoothing capacitor 160 and one end of the discharge resistor 310 are electrically connected, and the discharge of the smoothing capacitor 160 becomes possible. When the open / close switch is in the off state, the electrical connection between one end of the smoothing capacitor 160 and one end of the discharge resistor 310 is interrupted, and the discharge of the smoothing capacitor 160 is not performed. This open / close switch 330 may be an electrical switch such as a transistor (including a non-contact relay), or a mechanical switch such as a contact relay. In FIG. 2, the open / close switch is a MOSFET, and for the open / close switch 330, the source is connected to one end of the smoothing capacitor 160, and the drain is connected to one end of the discharge resistor 310. Further, the gate of the open / close switch 330 is connected to one end of the smoothing capacitor 160 via a delay circuit 340.

[0029] The delay circuit 340 delays the timing at which the discharge switch 320 becomes on so that the discharge switch 320 becomes on after the activation of the control unit 220 is completed. The delay circuit 340 delays the timing at which the discharge switch 320 becomes on by delaying the open / close switch 330 from becoming on when the activation of the discharge device 170 starts. For example, the delay circuit 340 is a parallel circuit of a resistor and a capacitor C, and is connected between the gate and the source of the open / close switch 330.

[0030] The control unit 220 gives an instruction to the discharge circuit 210 to discharge the smoothing capacitor 160 (discharge process). As an example, the control unit 220 includes two output terminals P1 and P2. When the control unit 220 gives an instruction for the discharge process to the discharge circuit 210, it outputs a discharge signal indicating the instruction for the discharge process from the output terminal P1. The discharge signal is, for example, a high-level voltage signal. Also, when the control unit 220 is operating normally, it outputs a specific signal (hereinafter referred to as the "specific signal") from the output terminal P2. That is, the specific signal is output from the output terminal P2 when the control unit 220 is operating normally, and the output from the output terminal P2 stops when an abnormality occurs in the control unit 220. Thus, the specific signal disappears when an abnormality occurs in the control unit 220. Note that the case where an abnormality occurs in the control unit 220 is an abnormality in which an instruction for the discharge process cannot be given, that is, the discharge signal cannot be output normally, such as when the control unit 220 fails or when sufficient power supply to the control unit 220 is interrupted. For example, the specific signal is a signal indicating that the control unit 220 is normal, and is, as an example, a pulse signal.

[0031] The control unit 220 has a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). Also, the control unit 220 may include a non-volatile or volatile semiconductor memory (e.g., RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory)) in addition to the processor. For example, the control unit 220 may be a microcontroller such as an MCU.

[0032] When the control unit 220 cannot give an instruction for the discharge process, the interface circuit 230 gives an instruction for the discharge process to the discharge circuit 210. For example, the interface circuit 230 is connected to each of the output terminal P1 and the output terminal P2 of the control unit 220. When a discharge signal is input from the output terminal P1, the interface circuit 230 controls the discharge switch 320 to be in the on state by inputting the discharge signal or a signal generated from the discharge signal to the discharge switch 320.

[0033] When a specific signal is input from the output terminal P2, the interface circuit 230 maintains the discharge switch 320 in the off state unless a discharge signal is output from the output terminal P1. When the specific signal disappears, the interface circuit 230 gives an instruction for discharge to the discharge circuit 210. That is, when the specific signal disappears, the interface circuit 230 controls the discharge switch 320 to be in the on state. At this time, the interface circuit 230 may control the discharge switch 320 to be in the on state by the charge of the smoothing capacitor 160.

[0034] An example of the schematic configuration of the interface circuit 230 according to the present embodiment will be described below. The interface circuit 230 includes a first driver circuit 410, a second driver circuit 420, an adjustment switch 430, and diodes D1 and D2.

[0035] The first driver circuit 410 is connected to the output terminal P1, and when input from the output terminal P1, outputs to the base of the discharge switch 320 via the diode D1. For example, the first driver circuit 410 is composed of one or more transistors, resistors, and the like.

[0036] The second driver circuit 420 is connected to the output terminal P2 and receives an input from the output terminal P1. The second driver circuit 420 is connected to the adjustment switch 430 and controls the adjustment switch 430 to be in an on state or an off state according to a specific signal from the output terminal P1. In the example shown in FIG. 2, when a specific signal is input from the output terminal P2, the second driver circuit 420 controls the adjustment switch 430 to be in an on state, and when the specific signal is not input from the output terminal P2 (when the specific signal has disappeared), the second driver circuit 420 controls the adjustment switch 430 to be in an off state.

[0037] The anode of the diode D1 is connected to the output of the first driver circuit 410, and the cathode is connected to the base of the discharge switch 320.

[0038] The anode of the diode D2 is connected to one end of the discharge resistor 310, and the cathode is connected to the base of the discharge switch 320. The cathode of the diode D2 is connected to the cathode of the diode D1.

[0039] The adjustment switch 430 is a switch connected between the anode of the diode D2 and the ground. The adjustment switch 430 may be an electrical switch such as a transistor (including a reed relay) or a mechanical switch such as a contact relay. In the example shown in FIG. 2, the adjustment switch 430 is a transistor. The collector of the adjustment switch 430 is connected to the anode of the diode D2, the emitter is connected to the ground, and the base is connected to the output of the second driver circuit 420.

[0040] Next, an example of the operation of the discharge device 170 according to the present embodiment will be described. First, the operation of the discharge device 170 when the control unit 220 is operating normally will be described with reference to FIGS. 3 and 4.

[0041] FIG. 3 is a timing chart of the operation of the discharge device 170 when the control unit 220 is operating normally. FIG. 4 is a diagram for explaining the operation of the interface circuit 230 when the control unit 220 is operating normally. As an initial state of FIG. 3, the opening / closing switch 330 is in the on state, and the discharge signal has not been output yet. Note that V BE indicates the voltage between the base and the emitter. Also, the voltage of the capacitor C for the delay circuit indicates the gate voltage of the opening / closing switch 330.

[0042] As shown in FIG. 3, since the control unit 220 is operating normally, a specific signal is output from the output terminal P2. In this case, the second driver circuit 420 controls the adjustment switch 430 to be in the on state according to the specific signal. In the example shown in FIG. 3, the specific signal is a pulse signal. Therefore, the second driver circuit 420 maintains the adjustment switch 430 in the on state by outputting a pulse signal having the same frequency as the specific signal to the base of the adjustment switch 430. When the adjustment switch 430 is in the on state, the anode of the diode D2 becomes substantially the same potential as the ground. Therefore, when the discharge signal is not output, the potential of the base of the discharge switch 320 is controlled to the L level, so the discharge switch 320 is in the off state.

[0043] After the contactors (the first contactor 120 and the second contactor 130) are controlled from the on state to the off state at time t1, it is assumed that a discharge signal is output from the output terminal P1 at time t2. When the discharge signal is output from the output terminal P1, the first driver circuit 410 outputs the discharge signal or a signal corresponding to the discharge signal to the base of the discharge switch 320. As a result, at time t3, the discharge switch 320 changes from the off state to the on state, and the discharge of the charge of the smoothing capacitor 160 is started. Note that, along with the discharge of the charge of the smoothing capacitor 160, the charge of the capacitor C in the delay circuit 340 is also discharged. Here, as shown in FIG. 3, even during the period when the discharge signal is being output, if the control unit 220 is operating normally, a specific signal is being output. That is, the adjustment switch 430 remains in the on state. However, a diode D2 is provided between the adjustment switch 430 and the base of the discharge switch 320, and a signal from the first driver circuit 410 is input to the cathode of the diode D2. Therefore, even when the adjustment switch 430 is in the on state, the first driver circuit 410 can control the discharge switch 320 to the on state in response to the discharge signal.

[0044] Next, the operation of the discharge device 170 when an abnormality occurs in the control unit 220 will be described with reference to FIGS. 5 and 6.

[0045] FIG. 5 is a timing chart of the operation of the discharge device 170 when an abnormality occurs in the control unit 220. FIG. 6 is a diagram for explaining the operation of the interface circuit 230 when an abnormality occurs in the control unit 220. As an initial state, similar to FIG. 3, the open / close switch 330 is in the on state and no discharge signal is being output.

[0046] After the contactors (the first contactor 120 and the second contactor 130) are controlled from the on state to the off state at time t11, assume that an abnormality occurs such as the operation of the control unit 220 stopping at time t12. In this case, at time t12, the output of the specific signal from the output terminal P2 stops. When the specific signal disappears, the second driver circuit 420 controls the adjustment switch 430 from the on state to the off state. In the example shown in FIG. 5, when the specific signal disappears, the pulse signal for maintaining the adjustment switch 430 in the on state is no longer output from the second driver circuit 420. As a result, the V BE of the adjustment switch 430 gradually decreases, and the adjustment switch 430 becomes off at time t13.

[0047] When the adjustment switch 430 becomes off at time t13, a path is formed for the charge of the smoothing capacitor 160 to flow through the open / close switch 330 and the diode D2 to the base of the discharge switch 320. As a result, the charge of the smoothing capacitor 160 flows to the base of the discharge switch 320, and the discharge switch 320 becomes on. In other words, when the specific signal disappears, the interface circuit 230 controls the discharge switch 320 to be on using the charge of the smoothing capacitor 160. When the discharge switch 320 is controlled to be on at time t13, the discharge of the charge of the smoothing capacitor 160 starts. Thus, even when an abnormality occurs in the control unit 220, the discharge device 170 of the present embodiment can execute the discharge process.

[0048] Next, the operation when the power is turned on to the discharge device 170 will be described with reference to FIG. 7.

[0049] FIG. 7 is an operation timing chart when the power is turned on to the discharge device 170. As an initial state, both the contactors (the first contactor 120 and the second contactor 130) and the open / close switch 330 are off. For the sake of convenience of explanation, in the example shown in FIG. 7, no abnormality has occurred in the control unit 220.

[0050] When the contactors (the first contactor 120 and the second contactor 130) are controlled from the off state to the on state at time t21, the discharge device 170 is powered on. When the contactors are in the on state, the positive terminal of the battery 110 is connected to the smoothing capacitor 160 and the opening / closing switch 330. Therefore, charging from the battery 110 to the smoothing capacitor 160 is started. Here, when the contactors are controlled to the on state, the delay circuit 340 suppresses a sudden rise in the gate voltage. That is, when the contactors are controlled to the on state, the delay circuit 340 gently raises the rise of the gate voltage (the voltage of the capacitor C) so that the opening / closing switch 330 does not immediately turn on, and delays the timing at which the opening / closing switch 330 turns on. In the example shown in FIG. 7, the opening / closing switch 330 transitions to the on state at time t23 when the gate voltage exceeds the threshold value Vth.

[0051] At time t22 when a certain time has elapsed from time t21, the control unit 220 starts operating. When the control unit 220 starts operating, a specific signal is output from the output terminal P2 to the second driver circuit 420. The second driver circuit 420 controls the adjustment switch 430 to the on state according to the specific signal. Thereby, the base voltage of the discharge switch 320 is maintained at the Low level.

[0052] At time t23 when a certain time has elapsed from time t22, the gate voltage of the opening / closing switch 330 exceeds the threshold value Vth. For this reason, at time t23, the opening / closing switch 330 transitions from the off state to the on state. Here, even when the opening / closing switch 330 transitions from the off state to the on state, since the adjustment switch 430 has already been maintained in the on state, the base voltage V BE of the discharge switch remains at the Low level (including approximately 0V), and the discharge switch 320 remains in the off state without transitioning to the on state. Thereby, it is possible to suppress the discharge switch 320 from turning on and the discharge process being erroneously executed when the discharge device 170 is powered on.

[0053] That is, if the delay circuit 340 is not provided, the opening / closing switch 330 may shift to the ON state immediately after the power supply to the discharge device 170 is turned on, and the opening / closing switch 330 may shift to the ON state before the control unit 220 starts up. When the control unit 220 is not started up, a specific signal is not output from the output terminal P2, so the adjustment switch 430 is in the OFF state. Therefore, if the opening / closing switch 330 shifts to the ON state before the control unit 220 starts up, current will flow from the battery 110 or the smoothing capacitor 160 to the base of the discharge switch 320, and the discharge switch 320 will become ON. As a result, an unintended discharge process will be executed.

[0054] In the present embodiment, the discharge device 170 includes a delay circuit 340 for suppressing malfunction of the discharge process when power is supplied to the discharge device 170. As an example, the delay circuit 340 provides a delay time from when power is supplied to the discharge device 170 until the opening / closing switch 330 becomes ON, and causes the opening / closing switch 330 to become ON after the control unit 220 is started up by the power supply to the discharge device 170. In other words, the delay circuit 340 controls the timing of the ON state of the opening / closing switch 330 so that the opening / closing switch 330 becomes ON after the adjustment switch 430 shifts to the ON state when power is supplied to the discharge device 170. With such a configuration, the discharge device 170 can suppress wasteful discharge.

[0055] As described above, when the control unit 220 of the discharge device 170 of the present embodiment cannot give an instruction to discharge to the discharge circuit 210 by a discharge signal, the interface circuit 230 gives an instruction to discharge to the discharge circuit 210.

[0056] With such a configuration, even when an abnormality occurs in the control unit 220, the discharge process can be executed.

[0057] As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and designs and the like within the scope not departing from the gist of the present invention are also included.

[0058] In the above embodiment, the stop of the output of the specific signal may be performed according to the determination of the control unit 220, or may be performed regardless of the determination of the control unit 220. For example, when the power supply to the control unit 220 is stopped due to some abnormality or when an abnormality occurs in the control unit 220 and the control unit 220 stops operating, the output of the specific signal is stopped regardless of the determination of the control unit 220. That is, the stop of the output of the specific signal in the present embodiment includes that the output of the specific signal is stopped because the control unit 220 cannot output the specific signal. However, it is not limited thereto. When only the function of outputting the discharge signal does not operate due to some abnormality, the control unit 220 may intentionally stop the output of the specific signal to give an instruction for the discharge process to the discharge circuit 210. That is, the stop of the output of the specific signal in the present embodiment may also include the case where the output of the specific signal is stopped according to the determination of the control unit 220.

[0059] FIG. 8 is a modified example of the discharge device 170 of the present embodiment. In the discharge device 170 shown in FIG. 8, the control unit 220 is configured to detect the voltage of the smoothing capacitor 160. Even though the control unit 220 outputs the discharge signal from the output terminal P1, when the voltage of the smoothing capacitor 160 does not decrease, the control unit 220 may stop the output of the specific signal from the output terminal P2. For example, if the voltage of the smoothing capacitor 160 does not fall below a preset voltage until a predetermined time has elapsed after the control unit 220 outputs the discharge signal from the output terminal P1, the control unit 220 may stop the output of the specific signal from the output terminal P2 on the assumption that there is a possibility that the discharge signal has not been output.

[0060] In the above-described embodiment, the case where the discharge process is executed includes, for example, the case where a PCU (Power Control Unit) such as the power conversion device 150 stops, the case where the ignition switch is turned off, the case where the power conversion device 150, the control unit 220, etc. malfunction due to a vehicle collision, and the like. However, in this embodiment, the timing for executing the discharge process is not particularly limited.

[0061] In the above-described embodiment, the control unit 220 may be provided with a determination function for determining whether an abnormality has occurred in the control unit 220, or a device (determination device) different from the control unit 220 may be provided. For example, the control unit 220 determines whether an abnormality has occurred in the control unit 220 (itself), and when it is determined that an abnormality has occurred, the output of a specific signal may be stopped. Also, for example, a determination device, which is a device different from the control unit 220, determines whether an abnormality has occurred in the control unit 220 by communicating with the control unit 220, and when it is determined that an abnormality has occurred in the control unit 220, the output of a specific signal may be stopped. The specific signal does not necessarily have to be output from the control unit 220, and may be output from, for example, the determination device.

[0062] The interface circuit 230 may be provided with the above-described determination function. In this case, the interface circuit 230 may determine the presence or absence of an abnormality in the control unit 220 based on whether the specific signal has disappeared. When the specific signal has disappeared, the interface circuit 230 may determine that an abnormality has occurred in the control unit 220 and control the discharge switch 320 to be in the on state by turning off the adjustment switch 430.

[0063] The term "… unit" described in the specification means a unit that processes at least one function or operation, which may be embodied as hardware or software, or may be embodied as a combination of hardware and software.

Explanation of Reference Numerals

[0064] 100... Vehicle system, 110... Battery, 160... Smoothing capacitor, 170... Discharge device, 220... Control unit, 230... Interface circuit, 320... Discharge switch, 330... Open / close switch, 340... Delay circuit

Claims

1. A discharge circuit that discharges the charge stored in a smoothing capacitor, A control unit that gives an instruction to perform the discharge to the discharge circuit, When the control unit is unable to give an instruction to perform the discharge, an interface circuit that gives an instruction to perform the discharge to the discharge circuit, comprising: The discharge circuit includes a discharge switch for discharging the charge stored in the smoothing capacitor. When the discharge switch is controlled from the off state to the on state, the discharge is executed. The interface circuit controls the discharge switch to the on state by the charge of the smoothing capacitor when the control unit is unable to give an instruction to perform the discharge. The discharge switch includes a delay circuit that delays the timing at which the discharge switch becomes on so that the discharge switch becomes on after the activation of the control unit is completed. Discharge device.

2. When the control unit is operating normally, it outputs a specific signal to the interface circuit. When an abnormality occurs in which the instruction to perform the discharge cannot be given, the output of the specific signal is stopped. When the specific signal disappears, the interface circuit gives an instruction to perform the discharge to the discharge circuit. The discharge device according to claim 1.

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