JP7205401B2 - Relay failure determination device and DC power distribution device - Google Patents

Description

The present invention relates to a relay failure determination device for determining failure of a relay.

2. Description of the Related Art Among devices equipped with a DC power source, there is a device provided with a relay for the purpose of opening and closing an electric circuit between the DC power source and a load to which power is supplied from the DC power source. Failures occur in such relays due to various factors. There are two types of relay failures: a closed failure that does not open even though an open signal is given, and an open failure that remains open and does not close even though a close signal is given. can be broadly classified into A closing failure occurs when the contact cannot be driven due to, for example, disconnection of the coil that drives the contact of the relay. A closing failure is caused, for example, by welding between a fixed contact and a moving contact.

For example, Patent Literature 1 discloses determination of failure of a relay in an electric vehicle in which an inverter is driven by electric power from a power storage device and the power storage device is charged by a charging device from an external power supply. The relay is provided in each of the positive and negative power lines between the external power source and the power storage device in the charging device. In such a relay failure judgment, when switching noise is detected on the external power supply side of the relay while the two relays are controlled to be open during the switching operation of the inverter, the relay is welded. determine that there is

Japanese Patent No. 542100

In the electric vehicle disclosed in Patent Literature 1, the inverter needs to be operating in order to use the switching noise of the inverter to determine if the relay is welded. For this reason, in the electric vehicle, switching noise cannot be used when the inverter is stopped, so failure of the relay cannot be determined.

An object of one aspect of the present invention is to determine a relay failure even when a device that operates on a DC power supply is stopped.

In order to solve the above problems, a relay failure determination device according to one aspect of the present invention is a relay failure determination device that determines failures of a first relay and a second relay that open and close a power supply path from a DC power supply to a device. a first series circuit consisting of two resistors connected in series, both ends of which are respectively connected to the positive and negative electrodes of the DC power supply; a resistor circuit having a circuit and a second series circuit provided in parallel, wherein connection points of two resistors in each of the first series circuit and the second series circuit are connected to each other; and the second series circuit. A first voltage sensor connected to both ends of the first relay and the second relay based on the voltage detected by the first voltage sensor by controlling the first relay and the second relay to an open state a failure determination unit that determines that at least one of the relays has a closing failure, wherein the first relay is connected to one end of the first series circuit and one end of the second series circuit connected to the positive electrode. and the second relay is provided between the other end of the first series circuit connected to the negative electrode and the other end of the second series circuit.

According to the above configuration, when at least one of the first relay and the second relay is out of order, even if the first relay and the second relay are controlled to be open, the closed-failed relay is opened. Absent. In this state, current flows from the DC power supply through the closed relay to the first voltage sensor, so the first voltage sensor detects voltage. Therefore, the closing failure of the first relay and the second relay can be determined based on the presence or absence of voltage detection by the first voltage sensor.

The relay failure determination device further includes a second voltage sensor connected to a connection point of the two resistors in the first series circuit and the second series circuit, and the failure determination unit detects the failure of the first relay and the second series circuit. When the second voltage sensor detects a voltage when it is determined that at least one of the two relays has a closing failure, one of the first relay and the second relay is activated based on the polarity of the voltage. It may be determined that there is a closing failure.

According to the above configuration, when at least one of the first relay and the second relay has a closing failure, current flows from the DC power supply to the second voltage sensor via the closed relay. A voltage sensor detects the voltage. In addition, when one of the first relay and the second relay is closed, the direction of the current flowing through the second voltage sensor is reversed according to the closed relay. The polarity of the detected voltage is different. Therefore, it is possible to identify the relay with the closed failure by the polarity of the voltage.

In the relay failure determination device, the failure determination unit closes both the first relay and the second relay from a state in which it is determined that one of the first relay and the second relay has a closing failure. It may be determined that the other of the first relay and the second relay has an open failure when the second voltage sensor detects voltage by controlling.

With the above configuration, if both the first relay and the second relay are controlled to be in the closed state, the relay with the open failure remains open without being closed. In this state, a current flows through the first voltage sensor and the second voltage sensor through one of the relays that has failed to close, so the second voltage sensor detects the voltage. Thereby, it can be determined that the other of the first relay and the second relay has an open failure.

In the relay failure determination device, the failure determination unit controls the first relay and the second relay to be open so that when the first voltage sensor detects no voltage, the first relay and the second relay are opened. If the first voltage sensor detects no voltage by controlling both the second relays to the closed state, it is determined that both the first relay and the second relay have an open failure. The relay failure determination device according to any one of claims 1 to 3.

According to the above configuration, even if both the first relay and the second relay are controlled to be in the closed state, the first relay and the second relay with the open failure remain open. In this state, no current flows through the first relay and the second relay to the first voltage sensor, so the first voltage sensor does not detect voltage. Thereby, it can be determined that both the first relay and the second relay have an open failure.

In order to solve the above problems, a DC power distribution device according to an aspect of the present invention includes the DC power supply and any one of the relay failure determination devices.

According to one aspect of the present invention, failure of a relay can be determined even when a device that operates on a DC power supply is stopped.

1 is a block diagram showing the configuration of a DC power distribution device according to one embodiment of the present invention; FIG. 4 is a timing chart showing the operation of the relay failure determination device when the first relay and the second relay in the DC power distribution device are normal; FIG. 4 is a circuit diagram showing current flow in the failure determination device when only a first relay out of a first relay and a second relay in the DC power distribution device is closed; FIG. 4 is a circuit diagram showing current flow in the failure determination device when only a second relay of the first relay and the second relay in the DC power distribution device is closed; 4 is a flow chart showing a processing procedure of failure determination of a relay by a failure determination unit in the relay failure determination device;

[Embodiment]
An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG.

FIG. 1 is a block diagram showing the configuration of a DC power distribution device 10 according to one embodiment of the present invention.

As shown in FIG. 1, the DC power distribution device 10 includes a DC power supply 1, equipment 2, a relay failure determination device 3, a first relay Ry1, and a second relay Ry2.

In FIG. 1, the DC power supply 1, the first relay Ry1 and the second relay Ry2 are depicted as being included in the relay failure determination device 3 for the sake of convenience, but they are not included in the relay failure determination device 3.

A DC power supply 1 is a power supply that outputs DC power, and is composed of a battery, a solar battery, a generator, or the like.

The device 2 operates with DC power supplied from the DC power supply 1 . The device 2 is a solar battery connection facility (power conditioner), a charging device including a storage battery, or the like.

The first relay Ry<b>1 is a relay that opens and closes a positive feed path from the DC power supply 1 to the device 2 . The second relay Ry2 is a relay that opens and closes the negative feed path from the DC power supply 1 to the device 2 .

The relay failure determination device 3 is a device that determines failures of the first relay Ry1 and the second relay Ry2. The relay failure determination device 3 has a resistance circuit 4, a failure determination section 5, a first voltage sensor VS1, and a second voltage sensor VS2.

The resistance circuit 4 has a first series circuit 41 and a second series circuit 42 . The first series circuit 41 is composed of two resistors R1 and R2 connected in series, and both ends thereof are connected to the positive and negative electrodes of the DC power supply 1, respectively. Specifically, one end of the resistor R1 is connected to the positive terminal of the DC power supply 1, and one end of the resistor R2 is connected to the negative terminal of the DC power supply 1. The second series circuit 42 consists of two resistors R3 and R4 connected in series and is provided in parallel with the first series circuit. A connection point between the resistors R1 and R2 and a connection point between the resistors R3 and R4 are connected via a second voltage sensor VS2.

Here, the resistance values of the resistors R1 to R4 are not particularly limited, but the resistance values are set so that the ratio of the resistance values of the resistors R1 and R2 is equal to the ratio of the resistance values of the resistors R3 and R4. . For example, the resistance values of resistors R1 and R2 are set equal, and the resistance values of resistors R3 and R4 are set equal.

The first relay Ry1 is connected between one end of the first series circuit 41 connected to the positive electrode of the DC power supply 1 and one end of the second series circuit 42 on the resistor R3 side. The second relay Ry2 is connected between the other end of the first series circuit 41 connected to the negative electrode of the DC power supply 1 and the other end of the second series circuit 42 .

Failure determination unit 5 determines whether first relay Ry1 and second relay Ry2 have failed based on the voltage detected by first voltage sensor VS1 and the voltage detected by second voltage sensor VS2. The failure determination unit 5 has a drive control unit 51, a voltage determination unit 52, and a failure relay identification unit 53 for failure determination.

The drive control unit 51 gives or does not give an ON signal to the first relay Ry1 and the second relay Ry2 according to the failure determination procedure. The drive control unit 51 may be a control unit that controls the driving of the first relay Ry1 and the second relay Ry2 during normal operation. Open/close control is performed.

The voltage determination unit 52 determines whether or not there is a voltage detected by each of the first voltage sensor VS1 and the second voltage sensor VS2. Also, the voltage determination unit 52 determines the polarity of the voltage detected by the second voltage sensor VS2.

Faulty relay identification unit 53 identifies whether first relay Ry<b>1 and second relay Ry<b>2 have a closing failure or an opening failure based on the result of determination of the detected voltage by voltage determination unit 52 . Further, the faulty relay identification unit 53 instructs the drive control unit 51 to control opening and closing of the first relay Ry1 and the second relay Ry2 at predetermined timing according to the inspection procedure.

Normal operation of the first relay Ry1 and the second relay Ry2 by the DC power distribution device 10 configured as described above will be described.

FIG. 2 is a timing chart showing the operation of the relay failure determination device 3 when the first relay Ry1 and the second relay Ry2 in the DC power distribution device 10 are normal. FIG. 3 is a circuit diagram showing current flow in the relay failure determination device 3 when only the first relay Ry1 is closed. FIG. 4 is a circuit diagram showing current flow in the relay failure determination device 3 when only the second relay Ry2 is closed.

As shown in FIG. 2, when the ON signal (indicated by "ON" in the drawing) is applied to the first relay Ry1, while the ON signal is not applied to the second relay Ry2, as shown in Table 1, the second The first relay Ry1 is closed and the second relay Ry2 is opened (period T1). At this time, as shown in FIG. 3, the current from the DC power supply 1 passes through the first series circuit 41, the first relay Ry1, the resistor R3, the second voltage sensor VS2 and the resistor R2, and the first It flows through relay Ry1, first voltage sensor VS1, resistor R4 and a path through second voltage sensor VS2 and resistor R2.

As a result, as shown in FIG. 2 and Table 1, the detection voltage Vout output by the first voltage sensor VS1 is lower than the output voltage Vdc of the DC power supply 1 due to the current flowing through the resistors R1 to R4. there is Also, the detection voltage Vcenter output by the second voltage sensor VS2 is a positive value because a forward current flows through the second voltage sensor VS2.

As shown in FIG. 2, when the ON signal is not applied to both the first relay Ry1 and the second relay Ry2, as shown in Table 1, both the first relay Ry1 and the second relay Ry2 are opened (period T2). . At this time, no current flows from the DC power supply 1 through the first relay Ry1 and the second relay Ry2, so no current flows through the first voltage sensor VS1 and the second voltage sensor VS2. Therefore, as shown in FIG. 2 and Table 1, there is no detected voltage Vout output by the first voltage sensor VS1 and no detected voltage Vcenter output by the second voltage sensor VS2.

As shown in FIG. 2, when ON signals are applied to both the first relay Ry1 and the second relay Ry2, as shown in Table 1, both the first relay Ry1 and the second relay Ry2 are closed (period T3). At this time, a current flows through a path passing through the first relay Ry1, the first voltage sensor VS1 and the second relay Ry2. However, since the potential across the resistors R1 and R2 in the first series circuit 41 and the potential across the resistors R3 and R4 in the second series circuit 42 are equal, no current flows through the second voltage sensor VS2. As a result, as shown in FIG. 2 and Table 1, the detected voltage Vout output by the first voltage sensor VS1 becomes the output voltage Vdc of the DC power supply 1, and there is no detected voltage Vcenter output by the second voltage sensor VS2 (0 V). ).

As shown in FIG. 2, when the ON signal is not applied to the first relay Ry1, but is applied to the second relay Ry2, the first relay Ry1 is closed and the second relay Ry2 is opened ( period T4). At this time, as shown in FIG. 4, the current from the DC power supply 1 flows through the path of the first series circuit 41, the resistor R1, the second voltage sensor VS2, the resistor R3, the first voltage sensor VS1 and the second relay Ry2. and a path through resistor R1, second voltage sensor VS2, resistor R4 and second relay Ry2.

As a result, as shown in FIG. 2 and Table 1, the detection voltage Vout detected by the first voltage sensor VS1 is lower than the output voltage Vdc of the DC power supply 1 due to the current flowing through the resistors R1 to R4. there is Also, the detection voltage Vcenter output by the second voltage sensor VS2 has a negative value because a reverse current flows through the second voltage sensor VS2.

Next, the operation of failure determination of the first relay Ry1 and the second relay Ry2 by the relay failure determination device 3 will be described.

FIG. 5 is a flow chart showing a processing procedure of relay failure determination by the failure determination unit 5 in the relay failure determination device 3 .

First, when the DC power distribution device 10 shifts from the normal operation mode to the relay failure inspection mode, the failure relay identification unit 53 of the failure determination unit 5 outputs an instruction not to output the ON signal to the drive control unit 51 . In response to this instruction, drive control unit 51 does not give ON signals to both first relay Ry1 and second relay Ry2 (step S1).

Next, the voltage determination unit 52 determines whether or not the first voltage sensor VS1 has detected voltage (step S2). In step S2, when the voltage determination unit 52 determines that the first voltage sensor VS1 has detected a voltage (YES), the failure relay identification unit 53 performs It is determined that at least one (both or one) of the first relay Ry1 and the second relay Ry2 has a closing failure (step S3).

The voltage determination unit 52 determines whether or not the second voltage sensor VS2 has detected voltage in response to the determination of the closed failure by the failure relay identification unit 53 (step S4). When the voltage determination unit 52 determines that the second voltage sensor VS2 has detected a voltage in step S4 (YES), it determines whether the polarity of the voltage Vcenter detected by the second voltage sensor VS2 is positive (step S5). ).

In step S5, when the voltage determination unit 52 determines that the polarity of the detected voltage Vcenter is positive (YES), the failure relay identification unit 53 identifies that the first relay Ry1 has a closed failure (step S6). ). In this case, the second relay Ry2 may be open due to an open fault. The failure relay identification unit 53 outputs an instruction to output an ON signal to the drive control unit 51 in order to confirm the open failure of the second relay Ry2. In response to this instruction, drive control unit 51 gives ON signals to both first relay Ry1 and second relay Ry2 (step S7).

Next, the voltage determination unit 52 determines whether or not the second voltage sensor VS2 has detected voltage (step S8). In step S8, when the voltage determination unit 52 determines that the second voltage sensor VS2 has detected voltage (YES), the failure relay identification unit 53 determines that the second relay Ry2 has an open failure ( Step S9), the process ends. When the ON signal is given to the second relay Ry2, the normal second relay Ry2 is closed, but the second relay Ry2 with the open failure remains open. As a result, as shown in Table 1, the second voltage sensor VS2 detects a voltage Vcenter (positive).

In step S8, when the voltage determination unit 52 determines that the second voltage sensor VS2 has not detected the voltage (NO), the failure relay identification unit 53 determines that the second relay Ry2 is normal (step S10), the process ends.

Further, in step S5, when the voltage determination unit 52 determines that the polarity of the detected voltage Vcenter is not positive (negative) (NO), the failure relay identification unit 53 determines that the second relay Ry2 has closed failure. (Step S11). In this case, the first relay Ry1 may be open due to an open fault. The failure relay identification unit 53 outputs an instruction to output an ON signal to the drive control unit 51 in order to confirm the open failure of the first relay Ry1. In response to this instruction, drive control unit 51 provides ON signals to both first relay Ry1 and second relay Ry2 (step S12).

Next, the voltage determination unit 52 determines whether or not the second voltage sensor VS2 has detected voltage (step S13). In step S13, when the voltage determination unit 52 determines that the second voltage sensor VS2 has detected voltage (YES), the failure relay identification unit 53 determines that the first relay Ry1 has an open failure ( Step S14), the process ends. When an ON signal is given to the first relay Ry1, the normal first relay Ry1 closes, but the first relay Ry1 with the open failure remains open. As a result, as shown in Table 1, the second voltage sensor VS2 detects a voltage Vcenter (negative polarity).

In step S13, when the voltage determination unit 52 determines that the second voltage sensor VS2 has not detected the voltage (NO), the failure relay identification unit 53 determines that the first relay Ry1 is normal (step S15), the process ends.

Further, in step S4, when the voltage determination unit 52 determines that the second voltage sensor VS2 has not detected the voltage (NO), the failure relay identification unit 53 determines that both the first relay Ry1 and the second relay Ry2 It is determined that there is a closing failure (step S16), and the process ends.

Further, in step S2, if the voltage determination unit 52 determines that the first voltage sensor VS1 did not detect the voltage (NO), there is a possibility that both the first relay Ry1 and the second relay Ry2 have an open failure. There is In order to confirm this state, failure relay identification unit 53 outputs an instruction to output an ON signal to drive control unit 51 . In response to this instruction, drive control unit 51 gives ON signals to both first relay Ry1 and second relay Ry2 (step S17).

Next, the voltage determination unit 52 determines whether or not the first voltage sensor VS1 has detected voltage (step S18). In step S18, when the voltage determination unit 52 determines that the first voltage sensor VS1 has not detected the voltage (NO), the failure relay identification unit 53 determines that both the first relay Ry1 and the second relay Ry2 have an open failure. It is determined that it is (step S19), and the process ends.

When ON signals are applied to both the first relay Ry1 and the second relay Ry2, both the normal first relay Ry1 and the second relay Ry2 are closed, but the open-faulted first relay Ry1 and the second relay Ry2 are opened. remain. Therefore, as shown in Table 1, there is no voltage Vout detected by the first voltage sensor VS1.

Further, in step S18, when the voltage determination unit 52 determines that the first voltage sensor VS1 has detected voltage (YES), the failure relay identification unit 53 determines that both the first relay Ry1 and the second relay Ry2 are normal. (step S20), and the process ends. When ON signals are given to both the first relay Ry1 and the second relay Ry2, as shown in Table 1, both the normal first relay Ry1 and the second relay Ry2 are closed, so the detection voltage Vout of the first voltage sensor VS1 becomes a state where there is

As described above, the DC power distribution device 10 according to this embodiment includes the DC power supply 1 and the relay failure determination device 3 . The relay failure determination device 3 includes a resistance circuit 4 including a first series circuit 41 and a second series circuit, a failure determination section 5, a first voltage sensor VS1, and a second voltage sensor VS2. Failure determination unit 5 controls at least one of first relay Ry1 and second relay Ry2 based on the voltage detected by first voltage sensor VS1 by controlling first relay Ry1 and second relay Ry2 to the open state. It is determined that one of them has a closing failure. Also, the first relay Ry1 is provided between one end of the first series circuit 41 and one end of the second series circuit 42 connected to the positive electrode of the DC power supply 1 . The second relay Ry2 is provided between the other end of the first series circuit 41 and the other end of the second series circuit 42 connected to the negative electrode of the DC power supply 1 .

In the above configuration, if neither the first relay Ry1 nor the second relay Ry2 is out of order, the first relay Ry1 and the second relay Ry2 will open when controlled to be open. In this state, no current flows from the DC power supply 1 to the first voltage sensor VS1 through the open relay, so the first voltage sensor VS1 does not detect voltage.

On the other hand, when at least one of the first relay Ry1 and the second relay Ry2 is out of order, even if the first relay Ry1 and the second relay Ry2 are controlled to be open, the closed relay is closed. will not open. In this state, current flows from the DC power supply 1 to the first voltage sensor VS1 through the closed relay, so the first voltage sensor VS1 detects voltage. Therefore, the closed failure of the first relay Ry1 and the second relay Ry2 can be determined depending on whether or not the voltage is detected by the first voltage sensor VS1.

Further, the relay failure determination device 3 includes a second voltage sensor connected to a connection point of the two resistors R1 and R2 in the first series circuit 41 and a connection point of the two resistors R3 and R4 in the second series circuit 42. I have more. Moreover, when the failure determination unit 5 determines that at least one of the first relay Ry1 and the second relay Ry2 has a closed failure and the second voltage sensor VS2 detects a voltage, the polarity of the voltage is changed. Based on this, it is determined that one of the first relay Ry1 and the second relay Ry2 has a closing failure.

According to the above configuration, when at least one of the first relay Ry1 and the second relay Ry2 has a closed failure, a current flows from the DC power supply 1 to the second voltage sensor VS2 via the closed relay. Therefore, the second voltage sensor VS2 detects the voltage. Further, when one of the first relay Ry1 and the second relay Ry2 is closed, the direction of the current flowing through the second voltage sensor VS2 is reversed according to the closed relay. The polarity of the voltage detected by sensor VS2 is different. Therefore, it is possible to identify which of the first relay Ry1 and the second relay Ry2 has the closed failure by the polarity of the voltage.

In addition, from the state where it is determined that one of the first relay Ry1 and the second relay Ry2 has a closed failure, the failure determination unit 5 controls both the first relay Ry1 and the second relay Ry2 to the closed state. When the two-voltage sensor VS2 detects voltage, it is determined that the other of the first relay Ry1 and the second relay Ry2 has an open failure.

When one of the first relay Ry1 and the second relay Ry2 has a closing failure, the other may have an opening failure, but it cannot be determined whether it is open under normal conditions or due to a failure. Therefore, by controlling both the first relay Ry1 and the second relay Ry2 to the closed state with the above configuration, the relay having the open failure is kept open without being closed. In this state, current flows through the first voltage sensor VS1 and the second voltage sensor VS2 through the one relay that has failed to close, so the voltage is detected by the second voltage sensor VS2. Accordingly, it can be determined that the other of the first relay Ry1 and the second relay Ry2 has an open failure.

Further, the failure determination unit 5 controls the first relay Ry1 and the second relay Ry2 to be open, thereby opening the first relay Ry1 and the second relay Ry2 when the first voltage sensor VS1 detects no voltage. If the first voltage sensor VS1 detects no voltage by controlling both to the closed state, it is determined that both the first relay Ry1 and the second relay Ry2 have an open failure.

When both the first relay Ry1 and the second relay Ry2 have an open failure, even if the first relay Ry1 and the second relay Ry2 are both controlled to be open as described above, the first relay Ry1 and the second relay Ry2 Relay Ry2 remains open. Therefore, it cannot be determined whether the door is opened normally or due to an open failure.

Therefore, according to the above configuration, even if both the first relay Ry1 and the second relay Ry2 are controlled to be in the closed state, the first relay Ry1 and the second relay Ry2 with the open failure remain open. In this state, no current flows through the first voltage sensor VS1 through the first relay Ry1 and the second relay Ry2, so the first voltage sensor VS1 does not detect voltage. Accordingly, it can be determined that both the first relay Ry1 and the second relay Ry2 have an open failure.

[Example of realization by software]
The control block (in particular, the failure determination section 5) of the DC power distribution device 10 may be implemented by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be implemented by software.

In the latter case, the DC power distribution device 10 is provided with a computer that executes program instructions, which are software for realizing each function. This computer includes, for example, one or more processors, and a computer-readable recording medium storing the above program. In the computer, the processor reads the program from the recording medium and executes it, thereby achieving the object of the present invention.

As the processor, for example, a CPU (Central Processing Unit) can be used. As the recording medium, a "non-temporary tangible medium" such as a ROM (Read Only Memory), a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. In addition, a RAM (Random Access Memory) for developing the above program may be further provided. Also, the program may be supplied to the computer via any transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program.

Note that one aspect of the present invention can also be implemented in the form of a data signal embedded in a carrier wave in which the program is embodied by electronic transmission.

[Additional notes]
The present invention is not limited to the above-described embodiments, but can be modified in various ways within the scope of the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. is also included in the technical scope of the present invention.

1 DC power supply 2 Device 3 Relay failure determination device 4 Resistance circuit 5 Failure determination unit 41 First series circuit 42 Second series circuit R1 to R4 Resistor Ry1 First relay Ry2 Second relay VS1 First voltage sensor VS2 Second voltage sensor

Claims (5)

A relay failure determination device for determining a failure of a first relay and a second relay that open and close a power supply path from a DC power supply to a device,
A first series circuit consisting of two resistors connected in series, both ends of which are respectively connected to the positive and negative electrodes of the DC power supply, and a first series circuit consisting of two resistors connected in series, parallel to the first series circuit. a resistor circuit having a second series circuit provided in the first series circuit and the connection points of the two resistors in each of the second series circuit are connected to each other;
a first voltage sensor connected across the second series circuit;
At least one of the first relay and the second relay has a closing failure based on the voltage detected by the first voltage sensor by controlling the first relay and the second relay to an open state. and a failure determination unit that determines that
The first relay is provided between one end of the first series circuit connected to the positive electrode and one end of the second series circuit,
A relay failure determination device, wherein the second relay is provided between the other end of the first series circuit connected to the negative electrode and the other end of the second series circuit. further comprising a second voltage sensor connected to the junction of the two resistors in the first series circuit and the second series circuit;
When the second voltage sensor detects a voltage when it is determined that at least one of the first relay and the second relay has a closing failure, the failure determination unit detects a voltage based on the polarity of the voltage. 2. The relay failure determination device according to claim 1, wherein it is determined that one of said first relay and said second relay has a closing failure. The failure determination unit controls both the first relay and the second relay to close from a state in which it is determined that one of the first relay and the second relay has a closing failure, thereby closing the second relay. 3. The relay failure determination device according to claim 2, wherein when a voltage sensor detects voltage, it determines that the other of said first relay and said second relay has an open failure. The failure determination unit closes both the first relay and the second relay when the first voltage sensor detects no voltage by controlling the first relay and the second relay to be open. 4. The method according to any one of claims 1 to 3, wherein if the first voltage sensor does not detect voltage by controlling the state, it is determined that both the first relay and the second relay have an open failure. 1. A relay failure determination device according to claim 1. the DC power supply;
A DC power distribution device comprising: the relay failure determination device according to any one of claims 1 to 4.

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