JP2009290978A - Method and device for detecting failure of vehicle power circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a failure of a precharge relay in a precharge circuit. <P>SOLUTION: The vehicle power circuit includes a capacitor arranged in parallel to a battery, a first relay disposed between one pole of the capacitor and one pole of the battery, a second relay arranged between the other pole of the capacitor and the other pole of the battery and the precharge circuit which is constituted of a precharge resistor, and a precharge relay, which are connected in series, and is arranged in parallel to the first relay. The failure detecting method has a first relay interrupting step of making the first relay in an interrupting state when the first and second relays are in a connection conduction state and a prescribed condition is achieved, a precharge relay connection step of making the precharge relay in a connection state from the interrupting state after the first relay interrupting step is performed and a precharge relay OFF failure decision step of determining an OFF failure where the precharge relay does not become the connection state when voltage of the capacitor drops after the precharge relay connection step is started. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a failure detection method and apparatus for a vehicle power supply circuit that connects between an electric load and a battery that operates the electric load, and belongs to the technical field of power system control of an automobile.

  In recent years, so-called hybrid vehicles and electric vehicles that use fuel and electricity or run only using electricity have been put into practical use. This type of vehicle includes a motor and a high voltage that operates the motor. The battery is installed.

  In a power supply circuit that connects an electric load such as a motor and a battery that operates the load, a smoothing capacitor is provided in parallel with the battery. This capacitor smoothes the electric power from the battery by temporarily storing the electric charge, and supplies the smoothed electric power to the electric load. Thereby, the stable electric power is supplied to the electric load. When the battery is charged by the motor, the capacitor smoothes the power from the motor and supplies the smoothed power to the battery.

  In addition, this type of power supply circuit is provided with a precharge circuit in order to prevent damage to the contacts of the main relay and the battery body. This is to prevent the main relay contacts from being damaged by a large current flowing from the battery to the capacitor at the moment when the battery and the capacitor are connected, and damage to the battery body due to overcurrent.

  Specifically, the configuration of the power supply circuit having the precharge circuit will be described. The power supply circuit includes a battery, a capacitor arranged in parallel with the battery, and one of the capacitor and the anode of the battery. An anode side relay for connecting / disconnecting, a cathode side relay for connecting / disconnecting between the other pole of the capacitor and the cathode of the battery, a precharge resistor and a precharge relay connected in series, and the anode A precharge circuit that is arranged in parallel to the side relay and connects / disconnects between one pole of the capacitor and the anode of the battery.

  When the battery and the capacitor are connected, in order to prevent damage to the main relay and the battery body due to sudden charging of the capacitor, the cathode side relay is first set to the connected state, and then the precharge relay is set to the connected state. Is done. As a result, the capacitor gradually accumulates the electric charge by the minute current reduced by the precharge resistor. And after a capacitor | condenser accumulate | stores the electric charge of predetermined electric quantity, an anode side relay will be in a connection state, and a precharge relay will be in the interruption | blocking state through the overlap of predetermined period. Thereby, the contact of the main relay and the battery main body are prevented from being damaged.

  Furthermore, this type of power supply circuit is provided with a device for diagnosing a failure of the circuit. For example, what is described in Patent Document 1 is whether the power supply circuit is normal or faulty based on the voltage value of the electric load (inverter) and the voltage value of the battery after precharging (the precharge relay is connected). In the case of determining that there is a failure, based on a comparison between the current value of the battery immediately after the start of precharge and the current value after the end of precharge, is a short circuit failure in the power supply circuit due to a large current flowing? Or it is determined whether it is a disconnection failure. By identifying the cause of the failure, the failed power supply circuit can be promptly repaired.

JP 2007-89240 A

  However, the power supply circuit failure diagnosis device described in Patent Document 1 cannot identify which part of the power supply circuit has failed, although the cause of the failure is specified. In particular, it is impossible to diagnose whether or not the precharge relay of the precharge circuit for protecting the contacts of the main relay and the battery body, which are important components of the power supply circuit, is out of order. In addition, when the precharge relay is out of order, how the precharge relay is out of order, for example, a fault that does not enter the cut-off state while connected (hereinafter referred to as “ON fault”), or is cut off. It is not possible to specify the type of failure that is not in the connected state in the state (hereinafter referred to as “OFF failure”).

  Therefore, in diagnosing a failure of a vehicle power supply circuit having a precharge circuit, the present invention can particularly determine whether or not the precharge relay of the precharge circuit is faulty. It is another object of the present invention to provide a failure detection method and apparatus for a vehicle power supply circuit that can also be determined.

In order to solve the above-mentioned problem, the invention described in claim 1
A battery that operates an electrical load;
A capacitor placed in parallel with the battery;
A first relay that connects / disconnects between one pole of the capacitor and one pole of the battery;
A second relay for connecting / disconnecting the other pole of the capacitor and the other pole of the battery;
A precharge circuit comprising a precharge resistor and a precharge relay connected in series, and arranged in parallel to the first relay to connect / cut off between one pole of the capacitor and one pole of the battery A failure detection method for a vehicle power supply circuit comprising:
A first relay disconnecting step of disconnecting the first relay when the first and second relays are in a connected energized state and a predetermined condition is satisfied;
A precharge relay connecting step of switching the precharge relay from a cut-off state to a connected state after performing the first relay cut-off step;
A precharge relay OFF failure determination step for determining an OFF failure in which the precharge relay is not connected when the voltage of the capacitor decreases after the precharge relay connection step is started.

The invention according to claim 2
In the vehicle power supply circuit failure detection method according to claim 1,
A precharge relay disconnecting step in which the precharge relay is disconnected after a predetermined time has elapsed after starting the precharge relay connecting step;
And a precharge relay ON failure determination step for determining an ON failure in which the precharge relay is not in a cutoff state when the voltage of the capacitor does not decrease after the precharge relay cutoff step is started.

Furthermore, the invention described in claim 3
A battery that operates an electrical load;
A capacitor placed in parallel with the battery;
A first relay that connects / disconnects between one pole of the capacitor and one pole of the battery;
A second relay for connecting / disconnecting the other pole of the capacitor and the other pole of the battery;
A precharge circuit comprising a precharge resistor and a precharge relay connected in series, and arranged in parallel to the first relay to connect / cut off between one pole of the capacitor and one pole of the battery A failure detection method for a vehicle power supply circuit comprising:
A first relay disconnecting step of disconnecting the first relay when the first and second relays are in a connected energized state and a predetermined condition is satisfied;
A precharge relay connecting step of switching the precharge relay from a cut-off state to a connected state after performing the first relay cut-off step;
A precharge relay disconnecting step in which the precharge relay is disconnected after a predetermined time has elapsed after starting the precharge relay connecting step;
And a precharge relay ON failure determination step for determining an ON failure in which the precharge relay is not in a cutoff state when the voltage of the capacitor does not decrease after the precharge relay cutoff step is started.

Furthermore, the invention according to claim 4
In the vehicle power circuit failure detection method according to any one of claims 1 to 3,
The predetermined condition is satisfied when the ignition switch is turned off.

On the other hand, the invention described in claim 5
A battery that operates an electrical load;
A capacitor placed in parallel with the battery;
Capacitor voltage detection means for detecting the voltage of the capacitor;
A first relay that connects / disconnects between one pole of the capacitor and one pole of the battery;
A second relay for connecting / disconnecting the other pole of the capacitor and the other pole of the battery;
A precharge circuit comprising a precharge resistor and a precharge relay connected in series, and arranged in parallel to the first relay to connect / cut off between one pole of the capacitor and one pole of the battery A failure detection device for a vehicle power supply circuit comprising:
A first relay cutoff control for setting the first relay to a cutoff state when the first and second relays are in a connection energized state and a predetermined condition is satisfied;
Relay control means for performing precharge relay connection control for switching the precharge relay from the cutoff state to the connected state after execution of the first relay cutoff control;
Precharge relay failure determination means for determining an OFF failure in which the precharge relay is not connected when the voltage detected by the capacitor voltage detection means drops after the precharge relay connection control by the relay control means is started. It is characterized by.

The invention according to claim 6
The failure detection apparatus for a vehicle power supply circuit according to claim 5,
The relay control means executes precharge relay cut-off control for turning off the precharge relay after a predetermined time has elapsed after starting the precharge relay connection control,
The precharge relay failure determination means determines that the precharge relay is not in the cutoff state when the voltage detected by the capacitor voltage detection means does not decrease after the precharge relay cutoff control is started by the relay control means. It is characterized by.

Furthermore, the invention according to claim 7 provides
A battery that operates an electrical load;
A capacitor placed in parallel with the battery;
A first relay that connects / disconnects between one pole of the capacitor and one pole of the battery;
A second relay for connecting / disconnecting the other pole of the capacitor and the other pole of the battery;
A precharge circuit comprising a precharge resistor and a precharge relay connected in series, and arranged in parallel to the first relay to connect / cut off between one pole of the capacitor and one pole of the battery A failure detection device for a vehicle power supply circuit comprising:
A first relay cutoff control for setting the first relay to a cutoff state when the first and second relays are in a connection energized state and a predetermined condition is satisfied;
After the execution of the first relay cutoff control, precharge relay connection control for switching the precharge relay from the cutoff state to the connected state;
Relay control means for executing precharge relay cutoff control for setting the precharge relay in a cutoff state after elapse of a predetermined time after starting the precharge relay connection control,
A precharge relay failure determining means for determining an ON failure in which the precharge relay is not shut off when the voltage detected by the capacitor voltage detecting means does not drop after the precharge relay cutoff control is started by the relay control means; It is characterized by.

Furthermore, the invention according to claim 8 provides
In the failure detection apparatus for a vehicle power supply circuit according to any one of claims 5 to 7,
The predetermined condition is satisfied when the ignition switch is turned off.

  According to the first aspect of the present invention, when the first and second relays are in the connection energized state and a predetermined condition is satisfied, the first relay is turned off and the precharge relay is changed from the cut off state to the connected state. In this case, if the voltage of the capacitor drops after the precharge relay is connected, the precharge relay is not actually energized even though it should be energized in the connected state. Then, it is determined that the precharge relay is not in a connected state and has an OFF failure. Thereby, the OFF failure in which the precharge relay is not connected is specified.

  According to the second aspect of the present invention, when the first and second relays are in the connection energized state and the predetermined condition is satisfied, the first relay is disconnected and the precharge relay is changed from the disconnected state to the connected state. . Then, after the precharge relay is connected and a predetermined time elapses, the precharge relay is turned off. If the voltage of the capacitor does not decrease after the precharge relay is turned off, the precharge relay is actually turned on even though it should be turned off and not turned on. Then, it is determined that the precharge relay is in an on-state failure that does not enter a cut-off state. As a result, an ON failure in which the precharge relay is not cut off is identified.

  Further, according to the third aspect of the present invention, when the first and second relays are in the connection energized state and the predetermined condition is satisfied, the first relay is turned off and the precharge relay is changed from the cut off state to the connected state. . Then, after the precharge relay is connected and a predetermined time elapses, the precharge relay is turned off. If the voltage of the capacitor does not drop after the precharge relay is turned off, the precharge relay is actually turned on even though it should be turned off and not turned on. It is determined that the precharge relay is in an on-state failure where the precharge relay is not shut off. As a result, an ON failure in which the precharge relay is not cut off is identified.

  Furthermore, according to the fourth aspect of the invention, the failure diagnosis of the precharge relay is performed when the ignition switch is turned off, ie, when a predetermined condition is satisfied. That is, the failure diagnosis of the precharge relay is reliably performed every time the traveling is completed. Thus, for example, if the failure determination result is notified immediately, the power supply circuit can be repaired before the next use of the automobile.

  On the other hand, according to the fifth aspect of the present invention, when the first and second relays are in the connection energized state and the predetermined condition is satisfied, the relay control means turns off the first relay and turns off the precharge relay. To connect. When the voltage of the capacitor detected by the capacitor voltage detection means drops after the precharge relay is connected, the precharge relay is actually energized even though it should have been connected and energized. In this case, the precharge relay failure determination means determines that the precharge relay is in an OFF failure that does not enter the connected state. Thereby, the OFF failure in which the precharge relay is not connected is specified.

  According to the sixth aspect of the present invention, when the first and second relays are in the connection energized state and the predetermined condition is satisfied, the relay control means sets the first relay in the disconnected state and the precharge relay in the disconnected state. To connect. Further, after a predetermined time has elapsed after setting the precharge relay in the connected state, the relay control means puts the precharge relay in the cutoff state. If the voltage of the capacitor detected by the capacitor voltage detection means does not decrease after the precharge relay is turned off, the precharge relay is actually turned on even though it should have been turned off and not turned on. Therefore, in this case, the precharge relay failure determination means determines that the precharge relay is in an ON failure that does not enter the cutoff state. As a result, an ON failure in which the precharge relay is not cut off is identified.

  Furthermore, according to the seventh aspect of the present invention, when the first and second relays are in the connection energized state and the predetermined condition is satisfied, the relay control means sets the first relay in the disconnected state and the precharge relay in the disconnected state. To connect. Further, after a predetermined time has elapsed after setting the precharge relay in the connected state, the relay control means puts the precharge relay in the cutoff state. If the voltage of the capacitor detected by the capacitor voltage detection means does not decrease after the precharge relay is turned off, the precharge relay is actually turned on even though it should have been turned off and not turned on. Therefore, in this case, the precharge relay failure determination means determines that the precharge relay is in an ON failure that does not enter the cutoff state. As a result, an ON failure in which the precharge relay is not cut off is identified.

  Furthermore, according to the invention described in claim 8, the failure diagnosis of the precharge relay is performed when the ignition switch is turned off, ie, when a predetermined condition is satisfied. That is, the failure diagnosis of the precharge relay is reliably performed every time the traveling is completed. Thus, for example, if the failure determination result is notified immediately, the power supply circuit can be repaired before the next use of the automobile.

  FIG. 1 schematically shows a so-called hybrid vehicle power supply circuit in which a vehicle power supply circuit failure detection method according to an embodiment of the present invention is implemented. In the figure, a solid line indicates an electric wire, and a dotted line indicates a control signal or a sensor detection signal.

  As shown in FIG. 1, the battery B is a high-voltage battery and is configured by combining a plurality of battery cells E, and the plurality of battery cells E are connected in series.

  The battery B supplies electric power to the motor M via the inverter IV when the motor M functions as a drive source during operation of the automobile. The battery B is charged by the motor M via the inverter IV when the motor M functions as a generator during deceleration of the automobile. Control for switching the motor M as a drive source or a generator is performed by an engine control unit (not shown).

  A capacitor C is arranged in parallel with the battery B. The capacitor C temporarily accumulates electric charges to smooth the power from the battery B, and supplies the smoothed power to the motor M via the inverter IV. When battery B is charged by motor M, capacitor C smoothes the power from motor M and supplies the smoothed power to battery B.

  Two relays are arranged between the capacitor C and the battery B. A positive relay for connecting or disconnecting the anode of the battery B and one pole of the capacitor C (first relay according to the claims, hereinafter referred to as “plus RLY”), a cathode of the battery B, A minus relay that energizes or de-energizes the other pole of the capacitor C (the second relay described in the claims, hereinafter referred to as “minus RLY”) is disposed. These relays are controlled by a battery controller which will be described later. When receiving an ON signal from the controller, the relay enters a connection state in which the capacitor C and the battery B are connected. It is configured to be in a state. Further, the connection state according to the ON signal is maintained until the OFF signal is transmitted, for example, so as to maintain the state corresponding to the previous signal until a different signal is transmitted.

A precharge circuit for precharging the capacitor C is arranged in parallel with the plus RLY. The precharge circuit includes a resistor R and a precharge relay connected in series with the resistor R (hereinafter referred to as “precharge RLY”).
It consists of and. Like the plus RLY and minus RLY, the precharge RLY is also controlled by the battery controller, and is configured to be connected when receiving an ON signal from the controller, and to be blocked when receiving an OFF signal. Further, the state corresponding to the previous signal is maintained until a different signal is transmitted.

Furthermore, a voltage sensor VBS for detecting a voltage V _B of the battery B, and a voltage sensor VCS are arranged for detecting a voltage V _C of the capacitor C. These sensors are configured to transmit a signal corresponding to the detected voltage value to the battery controller.

  The battery controller B-CON controls plus RLY, minus RLY, and precharge RLY, and is configured to control three RLYs based on signals from the two voltage sensors VBS and VCS. Yes. Further, the battery controller B-CON receives an IG signal transmitted from the engine control unit and corresponding to the driver's ignition switch ON / OFF operation, and controls the three RLYs based on the IG signal. It is configured.

  From here, the failure detection of the power supply circuit shown in FIG. 1 performed by the battery controller B-CON will be described.

  2 and 4 are flowcharts showing the flow of control that is performed by the battery controller B-CON and that identifies a fault location in the power supply circuit. 3 shows a voltage application state of the power supply circuit that is changed by the failure detection control of the power supply circuit according to the flow of FIG. 2, and FIG. 5 shows a voltage application state of the power supply circuit corresponding to the flow of FIG. . In FIGS. 3 and 5, bold lines indicate a state in which a voltage is applied.

  First, the flow shown in FIG. 2 is a flow for detecting a failure of the power supply circuit started upon receiving the ignition switch ON signal (step S100). At this time, as shown in FIG. 3A, plus RLY, minus RLY, and precharge RLY are in a cut-off state.

When the ON signal of the ignition switch is received and the failure detection of the power supply circuit is started, the battery controller B-CON, in step S110, based on the detection result of the battery voltage sensor VBS (based on the signal from the battery voltage sensor VBS). ), It is determined whether or not the battery voltage V _B is zero. If zero, the process proceeds to step S120. Otherwise, the process proceeds to step S130, and it is determined that the battery B is abnormal. Then, the failure detection ends. In addition, as abnormality of the battery B, there exist the fuse F arrange | positioned between the battery cells E shown in FIG. 1, for example, or the battery B has discharged completely.

  Next, the battery controller B-CON transmits an ON signal to the precharge RLY in step S120.

Subsequent step S140, the battery controller B-CON, based on the capacitor voltage sensor VCS detection result, determines whether or not capacitor voltage _{V C} is zero. If zero, the process proceeds to step S150. Otherwise, the process proceeds to step S160, and it is determined that the minus RLY has an ON failure.

To explain, when the minus RLY is not ON failure, that is, when it is in the cut-off state, as shown in FIG. 3B, the capacitor C is applied with a voltage only to the pole on the precharge RLY side. V _C is zero. Therefore, the capacitor voltage V _C is not zero, despite expected negative RLY is not energized by the cut-off state, it will have been energized in practice. That is, it means that minus RLY has an ON failure.

  Battery controller B-CON transmits an ON signal to minus RLY in step S150. Then, the process proceeds to step S170 and waits until a predetermined time (for example, 500 ms) elapses.

After a predetermined time, the battery controller B-CON, at step 180, based on the capacitor voltage sensor VCS detection result, determines whether or not capacitor voltage V _C is rising. If so, the process proceeds to step S190. Otherwise, the process proceeds to step S200, and it is determined that the minus RLY or the precharge RLY has an OFF failure.

To explain, when both the negative RLY and the precharge RLY are not OFF-failed, that is, when both are connected, as shown in FIG. 3C, the voltage is applied to both poles of the capacitor C. capacitor voltage V _C is not zero. Further, since the minus RLY is in the connected state and only a predetermined time has elapsed (that is, during precharging), the capacitor voltage Vc is increasing. Therefore, the fact that the capacitor voltage Vc is not increasing means that the minus RLY is not energized even though it should have been energized by receiving the ON signal in step S150 and being connected. Or, even though the precharge RLY is supposed to be energized by receiving the ON signal in step S120, it is not actually energized. That is, it means that the minus RLY or the precharge RLY has an OFF failure.

  After the precharge is completed (when the capacitor C reaches the maximum charged amount), the battery controller B-CON transmits an ON signal to the plus RLY in step S190.

  Subsequently, in step S210, the battery controller B-CON transmits an OFF signal to the precharge RLY.

In step 220, the battery controller B-CON, based on the capacitor voltage sensor VCS detection result, determines whether or not capacitor voltage V _C is not reduced. If not, the flow control is terminated. Otherwise, the process proceeds to step S230, and it is determined that the plus RLY has an OFF failure.

To explain, when the plus RLY is not OFF failure, that is, in the connected state, as shown in FIG. 3D, a voltage is applied to both electrodes of the capacitor C, and the precharge is completed. Therefore, the capacitor voltage V _C is almost the same as the battery voltage V _B and does not decrease again. Accordingly, the capacitor voltage V _C is decreased, the positive RLY despite supposed to be energized in a connected state by receiving an ON signal at step S190, that is not actually energized Become. That is, it means that the plus RLY has an OFF failure.

  On the other hand, the flow shown in FIG. 4 is a flow for detecting a failure of the power supply circuit, which is started upon reception of the ignition switch OFF signal (step S300). At this time, plus RLY and minus RLY are in a connected state, and precharge RLY is in a cut-off state (the state shown in FIG. 3D).

  When the ignition switch OFF signal is received and the failure detection of the power supply circuit is started, the battery controller B-CON transmits an OFF signal to the plus RLY in step S310.

Next, the battery controller B-CON, at step S320, based on the capacitor voltage sensor VCS detection result, determines whether or not capacitor voltage _{V C} is decreased. If so, the process proceeds to step S330. Otherwise, the process proceeds to step S340, and it is determined that the plus RLY has an ON failure.

To explain, when the plus RLY is not ON failure, that is, when it is in the cut-off state, as shown in FIG. 5 (E), the voltage is applied only to the pole on the minus RLY side, as shown in FIG. The voltage V _C of the capacitor C that has been almost fully charged before is turned off decreases. Accordingly, the capacitor voltage V _C is not reduced, the positive RLY despite should not energized become blocked state by receiving the OFF signal in step S310, the will have been energized in practice. That is, plus RLY means that an ON failure has occurred.

  In step S330, the battery controller B-CON transmits an ON signal to the precharge RLY. Then, the process proceeds to S350 and waits for a predetermined time (waits until the capacitor C is charged to some extent).

When the predetermined time has elapsed, in step S360, battery controller B-CON, based on the capacitor voltage sensor VCS detection result, determines whether or not capacitor voltage V _C is not reduced. If not, the process proceeds to step S370. Otherwise, the process proceeds to step S380, and it is determined that the precharge RLY has an OFF failure.

To illustrate, when the pre-charge RLY is not OFF failure, if that is in the connected state, as shown in FIG. 5 (F), since a voltage is applied to both electrodes of capacitor C, the capacitor voltage V _C is decreased do not do. Accordingly, the capacitor voltage V _C is lowered, so that the precharge RLY despite supposed to be energized in a connected state by receiving an ON signal at step S330, does not actually energized . That is, it means that the precharge RLY has an OFF failure.

  In step S370, the battery controller B-CON transmits an OFF signal to the precharge RLY.

Subsequently, in step S390, battery controller B-CON, based on the capacitor voltage sensor VCS detection result, determines whether or not capacitor voltage _{V C} is decreased. If so, the process proceeds to step S400. Otherwise, the process proceeds to step S410, and it is determined that the precharge RLY has an ON failure.

To explain, when the precharge RLY is not in an ON failure, that is, in the cutoff state, the voltage is applied only to the negative RLY side pole of the capacitor C, as shown in FIG. V _C is reduced. Accordingly, the capacitor voltage V _C is not lowered, so that the precharge RLY Despite should not energized become blocked state by receiving the OFF signal in step S370, are energized in practice . That is, it means that the precharge RLY has an ON failure.

  In step S400, the battery controller B-CON transmits an OFF signal to minus RLY. As shown in FIG. 5H, the capacitor C is in a state where no voltage is applied to both electrodes.

  The battery controller B that determines (identifies) which of plus RLY, minus RLY, and precharge RLY has failed and whether the failure is an ON failure or an OFF failure by the flow control shown in FIGS. -CON notifies the driver of an abnormality identified by the control of the flow that starts when the ignition switch shown in FIG. 2 is turned ON, for example, by an alarm or a lamp before starting the engine. On the other hand, the failure identified by the flow control that starts when the ignition switch shown in FIG. 4 is turned OFF is notified to the driver immediately after the ignition switch is turned OFF, for example.

As described above, according to the present embodiment, when the plus RLY and minus RLY are in the connection energized state and the ignition switch is turned OFF, the plus RLY is set to the cutoff state and the precharge RLY is changed from the cutoff state to the connected state. Then, when the voltage V _C of the capacitor C after a precharge RLY in the connected state is lowered, the precharge RLY, despite supposed to be energized in a connected state does not actually energized Therefore, in this case, it is determined that the precharge RLY is not in a connected state and has an OFF failure. As a result, an OFF failure in which the precharge RLY is not connected is specified.

Further, when plus RLY and minus RLY are in the energized connection state and the ignition switch is turned off, plus RLY is turned off and precharge RLY is changed from the shut off state to the connected state. Subsequently, the precharge RLY is set in a connected state, and after a predetermined time has elapsed, the precharge RLY is set in a cutoff state. If the voltage V _{C of the} capacitor C does not decrease after the precharge RLY is turned off, the precharge RLY is actually turned on even though it should not be turned on and turned on. Therefore, in this case, it is determined that the precharge RLY is not in the cutoff state and the ON failure has occurred. As a result, an ON failure in which the precharge RLY is not cut off is specified.

  Further, since the failure diagnosis of the precharge RLY is performed when the ignition switch is turned off, that is, the failure diagnosis of the precharge RLY is surely performed every time the traveling is finished. Thus, for example, if the failure determination result is notified immediately, the power supply circuit can be repaired before the next use of the automobile.

  So far, the present invention has been described with reference to one embodiment, but the present invention is not limited to this embodiment.

  For example, in the case of the above-described embodiment, the failure detection of the precharge RLY of the power supply circuit is started when a predetermined start condition is satisfied when the ignition switch is turned OFF as shown in FIG. The starting condition is not limited to this.

  For example, when a motor operated by a battery is not functioning as a drive source and a generator, that is, when the battery is fully charged and the vehicle is running on an engine, a failure detection of the precharge RLY is performed. If there is no problem, the failure detection of the precharge RLY may be performed using this as a predetermined start condition.

  In the case of the above-described embodiment, as shown in FIG. 4, both the ON failure and the OFF failure of the precharge RLY can be specified, but only the ON failure may be specified. This is applied only in the case of the precharge RLY that hardly causes an OFF failure (for example, it is applied to a relay or the like in which switch terminals are welded to each other and easily cause an ON failure).

  FIG. 6 shows a control flow of the battery controller that starts only when the ignition switch is turned OFF, which specifies only the ON failure of the precharge RLY.

  First, when an ignition switch OFF signal is received in step S500 and failure detection of the power supply circuit is started, the battery controller transmits an OFF signal to plus RLY in step S510.

Next, the battery controller, at step S520, on the basis of the detection result of the capacitor voltage sensor, determines whether or not the capacitor voltage V _C is decreased. If so, the process proceeds to step S530. Otherwise, the process proceeds to step S540, and it is determined that the plus RLY has an ON failure.

  Subsequently, in step S530, the battery controller transmits an ON signal to the precharge RLY. Then, the process proceeds to S550 and waits for a predetermined time (waits until the capacitor C is charged to some extent).

  When the predetermined time has elapsed, in step S560, the battery controller transmits an OFF signal to the precharge RLY.

In step S570, the battery controller, based on the detection result of the capacitor voltage sensor, determines whether or not the capacitor voltage V _C is decreased. If so, the process proceeds to step S580. Otherwise, the process proceeds to step S590, and it is determined that the precharge RLY has an ON failure.

In step S580, the battery controller transmits an OFF signal to minus RLY. And it ends.

  In this case, since the OFF failure of the precharge RLY is not detected as in the above-described embodiment, the control for detecting the failure is simplified as compared with the above-described embodiment.

  As described above, the vehicle power supply circuit failure detection method and apparatus according to the present invention are particularly suitable for diagnosing a failure in a vehicle power supply circuit having a precharge circuit. In the case of a failure, the failure mode can also be determined. Therefore, it may be suitably used in the field of automobile manufacturing industry having a power supply circuit including a precharge circuit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing an automobile power supply circuit including a vehicle power supply circuit failure detection device according to an embodiment of the present invention. It is a flowchart which shows the flow of a failure detection of the power supply circuit which starts when an ignition switch is turned ON. It is a figure which shows the change of the voltage application state of a power supply circuit corresponding to FIG. It is a flowchart which shows the flow of a failure detection of the power supply circuit which starts when an ignition switch is turned off. FIG. 5 is a diagram illustrating a change in voltage application state of the power supply circuit corresponding to FIG. 4. It is a flowchart which shows the flow of a failure detection of the power supply circuit which starts when an ignition switch is turned off by another form.

Explanation of symbols

B Battery C Capacitor VBS Battery voltage sensor VCS Capacitor voltage sensor M Motor IV Inverter B-CON Battery controller

Claims (8)

A battery that operates an electrical load;
A capacitor placed in parallel with the battery;
A first relay that connects / disconnects between one pole of the capacitor and one pole of the battery;
A second relay for connecting / disconnecting the other pole of the capacitor and the other pole of the battery;
A precharge circuit comprising a precharge resistor and a precharge relay connected in series, and arranged in parallel to the first relay to connect / cut off between one pole of the capacitor and one pole of the battery A failure detection method for a vehicle power supply circuit comprising:
A first relay disconnecting step of disconnecting the first relay when the first and second relays are in a connected energized state and a predetermined condition is satisfied;
A precharge relay connecting step of switching the precharge relay from a cut-off state to a connected state after performing the first relay cut-off step;
A failure of a power supply circuit for a vehicle, comprising a precharge relay OFF failure determination step for determining an OFF failure in which the precharge relay is not connected when the voltage of the capacitor decreases after the precharge relay connection step is started. Detection method. In the vehicle power supply circuit failure detection method according to claim 1,
A precharge relay disconnecting step in which the precharge relay is disconnected after a predetermined time has elapsed after starting the precharge relay connecting step;
And a precharge relay ON failure determination step for determining an ON failure in which the precharge relay does not enter a cutoff state when the voltage of the capacitor does not decrease after the precharge relay cutoff step is started. Fault detection method. A battery that operates an electrical load;
A capacitor placed in parallel with the battery;
A first relay that connects / disconnects between one pole of the capacitor and one pole of the battery;
A second relay for connecting / disconnecting the other pole of the capacitor and the other pole of the battery;
A precharge circuit comprising a precharge resistor and a precharge relay connected in series, and arranged in parallel to the first relay to connect / cut off between one pole of the capacitor and one pole of the battery A failure detection method for a vehicle power supply circuit comprising:
A first relay disconnecting step of disconnecting the first relay when the first and second relays are in a connected energized state and a predetermined condition is satisfied;
A precharge relay connecting step of switching the precharge relay from a cut-off state to a connected state after performing the first relay cut-off step;
A precharge relay disconnecting step in which the precharge relay is disconnected after a predetermined time has elapsed after starting the precharge relay connecting step;
And a precharge relay ON failure determination step for determining an ON failure in which the precharge relay does not enter a cutoff state when the voltage of the capacitor does not decrease after the precharge relay cutoff step is started. Fault detection method. In the vehicle power circuit failure detection method according to any one of claims 1 to 3,
The vehicle power supply circuit failure detection method according to claim 1, wherein the predetermined condition is satisfied when the ignition switch is turned off. A battery that operates an electrical load;
A capacitor placed in parallel with the battery;
Capacitor voltage detection means for detecting the voltage of the capacitor;
A first relay that connects / disconnects between one pole of the capacitor and one pole of the battery;
A second relay for connecting / disconnecting the other pole of the capacitor and the other pole of the battery;
A precharge circuit comprising a precharge resistor and a precharge relay connected in series, and arranged in parallel to the first relay to connect / cut off between one pole of the capacitor and one pole of the battery A failure detection device for a vehicle power supply circuit comprising:
A first relay cutoff control for setting the first relay to a cutoff state when the first and second relays are in a connection energized state and a predetermined condition is satisfied;
Relay control means for performing precharge relay connection control for switching the precharge relay from the cutoff state to the connected state after execution of the first relay cutoff control;
Precharge relay failure determination means for determining an OFF failure in which the precharge relay is not connected when the voltage detected by the capacitor voltage detection means drops after the precharge relay connection control by the relay control means is started. A failure detection device for a vehicle power supply circuit. The failure detection apparatus for a vehicle power supply circuit according to claim 5,
The relay control means executes precharge relay cut-off control for turning off the precharge relay after a predetermined time has elapsed after starting the precharge relay connection control,
The precharge relay failure determination means determines that the precharge relay is not in the cutoff state when the voltage detected by the capacitor voltage detection means does not decrease after the precharge relay cutoff control is started by the relay control means. A failure detection device for a vehicle power supply circuit. A battery that operates an electrical load;
A capacitor placed in parallel with the battery;
A first relay that connects / disconnects between one pole of the capacitor and one pole of the battery;
A second relay for connecting / disconnecting the other pole of the capacitor and the other pole of the battery;
A precharge circuit comprising a precharge resistor and a precharge relay connected in series, and arranged in parallel to the first relay to connect / cut off between one pole of the capacitor and one pole of the battery A failure detection device for a vehicle power supply circuit comprising:
A first relay cutoff control for setting the first relay to a cutoff state when the first and second relays are in a connection energized state and a predetermined condition is satisfied;
After the execution of the first relay cutoff control, precharge relay connection control for switching the precharge relay from the cutoff state to the connected state;
Relay control means for executing precharge relay cutoff control for setting the precharge relay in a cutoff state after elapse of a predetermined time after starting the precharge relay connection control,
A precharge relay failure determining means for determining an ON failure in which the precharge relay is not shut off when the voltage detected by the capacitor voltage detecting means does not drop after the precharge relay cutoff control is started by the relay control means; A failure detection device for a vehicle power supply circuit. In the failure detection apparatus for a vehicle power supply circuit according to any one of claims 5 to 7,
The vehicle power supply circuit failure detection apparatus according to claim 1, wherein the predetermined condition is satisfied when the ignition switch is turned off.

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