JP7679222B2 - Power supply and autonomous driving systems - Google Patents

Description

The present invention relates to a power supply device and an automatic driving system.

Conventionally, there is a redundant power supply system that has a first power supply and a second power supply so that the vehicle can be evacuated to a safe place and stopped even if a power failure occurs while the vehicle is running, and if an abnormality such as a ground fault occurs in one of the power supply systems, the other power supply system supplies power to the on-board equipment (load).

The redundant power supply system includes a first system that supplies power from a first power source to a first load, a second system that supplies power from a second power source to a second load that has the same functions as the first load, and an inter-system switch that can connect and disconnect the first and second systems (see, for example, Patent Document 1).

In addition, the redundant power supply system normally connects the inter-system switch to supply power from the first power supply to the first load and the second load, and when a power failure such as a ground fault occurs in the first system, the inter-system switch is shut off and power is supplied from the second power supply to the second load, thereby performing backup control.

JP 2019-62727 A

In this type of redundant power supply system, if a power failure is detected in the first or second system, the system switch may be shut off before backup control is performed, and the location of the anomaly may be identified by supplying power from each power supply to each load.

For this reason, if the second power source is charged based on the amount of power required for backup control, there is a risk that the power of the second power source during backup control will be depleted depending on the power used in the process of identifying the abnormality.

The present invention has been made in consideration of the above, and aims to provide a power supply device and an autonomous driving system that can perform charging control that takes into account processing to identify abnormalities.

In order to solve the above-mentioned problems and achieve the object, the power supply device according to the present invention comprises a first system, a second system, an inter-system switch, a power switch, and a control unit. The first system supplies power from a first power source to a first load. The second system supplies power from a second power source to a second load. The inter-system switch connects or disconnects the first system and the second system. The power switch connects or disconnects the second power source and the second system. When the first system and the second system are normal, the control unit performs normal control to connect the inter-system switch and disconnect the power switch, and when a power failure of the first system or the second system is detected, the control unit disconnects the inter-system switch and connects the power switch, thereby performing abnormality detection control to detect an abnormality in the first system or the second system. When no abnormality is detected in the first system and the second system by the abnormality detection control, the control unit switches to the normal control and stores the amount of voltage drop of the second power source caused by the abnormality detection control in a storage unit, and when charging the second power source, charges the second power source until the voltage becomes equal to or greater than the driving voltage required to drive the second load plus the amount of voltage drop.

According to the present invention, charging control can be performed that takes into account processing to identify abnormalities.

FIG. 1 is a diagram illustrating an example of the configuration of an autonomous driving system including a power supply device according to an embodiment. FIG. 2 is a diagram illustrating an example of an operation of the abnormality detection control. FIG. 3 is a diagram illustrating an example of the operation of the evacuation travel control. FIG. 4 is a diagram showing an example of the operation of the charging control. FIG. 5 is a diagram illustrating an example of an operation for notifying the propriety of autonomous driving. FIG. 6 is a diagram showing an example of an operation of the vehicle control device to determine whether or not autonomous driving is possible. FIG. 7 is a flowchart showing the procedure of processing executed by the power supply device according to the embodiment. FIG. 8 is a flowchart showing the procedure of the charge control process executed by the power supply device according to the embodiment.

Embodiments of the power supply device disclosed in the present application will be described in detail below with reference to the attached drawings. Note that the present invention is not limited to the embodiments described below. The power supply device according to the embodiment is mounted on a vehicle having an autonomous driving function and supplies power to a load related to the autonomous driving control.

Figure 1 is a diagram showing an example of the configuration of an autonomous driving system S including a power supply device 1 according to an embodiment. As shown in Figure 1, the autonomous driving system S includes a power supply device 1, a first power source 10, a vehicle control device 100, a first load 101, and a second load 102.

The first load 101 includes a load related to autonomous driving. For example, the first load 101 includes a steering motor, an electric brake device, an in-vehicle camera, a radar, and the like that operate during autonomous driving. The first load 101 may also include general loads that are not related to autonomous driving, such as a display, an air conditioner, an audio device, a video device, and various lights.

The second load 102 includes a load related to autonomous driving. For example, the first load 101 includes a steering motor, an electric brake device, an on-board camera, a radar, and the like that operate during autonomous driving.

The vehicle control device 100 is a control device that operates the first load 101 and the second load 102 to perform automatic driving control of the vehicle.

The first power source 10 includes a DC/DC converter 11 (hereinafter referred to as DC/DC 11) and a lead battery 12 (hereinafter referred to as PbB 12). Note that the battery of the first power source 10 may be any secondary battery other than PbB 12.

The DC/DC 11 is connected upstream to a generator that converts the vehicle's regenerative energy into electricity to generate power, and transforms and outputs the input voltage input from the generator. If the vehicle is equipped with an engine, the generator may be an alternator that converts the rotational force of the engine into electricity to generate power. The DC/DC 11 charges the PbB 12, supplies power to the first load 101, supplies power to the second load 102, and charges the second power source 20 described below.

The power supply device 1 is a device that controls the power supply to the first load 101 and the second load 102. As shown in FIG. 1, the power supply device 1 includes a second power source 20, an inter-system switch 4, a control unit 31, a memory unit 32, and voltage sensors 51 and 52.

The second power source 20 is a backup power source in case the first power source 10 is unable to supply power. The second power source 20 comprises a lithium ion battery 21 (hereinafter referred to as "LiB21") and a power source switch 22. The power source switch 22 connects the LiB21 and the second load 102 so that they can be connected/disconnected. Note that the battery of the second power source 20 may be any secondary battery other than the LiB21.

The power supply device 1 also includes a first system 110 that supplies power from the first power source 10 to the first load 101, and a second system 120 that supplies power from the second power source 20 to the second load 102.

The system-to-system switch 4 connects the first system 110 and the second system 120 in a manner that allows connection/disconnection.

The voltage sensor 51 is connected between the first power source 10 and the first load 101, and detects the voltage value of the first system 110. The voltage sensor 52 is connected between the second power source 20 and the second load 102, and detects the voltage value of the second system 120.

The control unit 31 includes a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and various circuits. The control unit 31 may be configured with hardware such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array). The storage unit 32 is a storage unit configured with storage devices such as non-volatile memory, data flash, and hard disk drive. The storage unit 32 stores information on the amount of degradation, which will be described later, various programs, etc.

The control unit 31 controls the operation of the power supply device 1 by having the CPU execute a program stored in the ROM using the RAM as a working area. The control unit 31 supplies power from the first power source 10 or the second power source 20 to the first load 101 and the second load 102 by controlling the on/off of the inter-system switch 4 and the power switch 22 based on the detection results (voltage values) input from the voltage sensors 51 and 52.

Figure 1 shows an example of control during normal operation (normal control) when no abnormality such as a ground fault occurs in the first system 110 and the second system 120. Specifically, during normal control, the control unit 3 turns on the inter-system switch 4 and turns off the power supply switch 22.

As a result, power is supplied from the first power source 10 to the first load 101 via the first system 110, and power is supplied from the first power source 10 to the second load 102 via the first system 110, the inter-system switch 4, and the second system 120. This normal control is performed whether the vehicle is in automatic or manual driving mode.

Now, assume that during normal control in autonomous driving, the voltage value of the voltage sensor 51 drops below a predetermined threshold value for determining a ground fault (abnormality). In other words, assume that a power failure in the first system 110 or the second system 120 is detected based on the voltage value of the voltage sensor 51. In such a case, since there is a possibility that an abnormality such as a ground fault has occurred in the first system 110 or the second system 120, the power supply device 1 switches from normal control to abnormality detection control to identify the location of the abnormality.

Here, the abnormality detection control will be described with reference to FIG. 2. FIG. 2 is a diagram showing an example of the operation of the abnormality detection control. During normal control, when the voltage value of the voltage sensor 51 falls below a predetermined threshold, the control unit 31 of the power supply device 1 turns off the system switch 4 and turns on the power supply switch 22.

As a result, the connection between the first system 110 and the second system 120 is cut off, and power is supplied to the first load 101 by the first power source 10, and power is supplied to the second load 102 by the second power source 20.

The control unit 31 then detects whether or not an abnormality has occurred in each of the first system 110 and the second system 120 based on the voltage values of the voltage sensors 51 and 52. Specifically, the control unit 31 detects whether or not an abnormality has occurred in the first system 110 based on the voltage value of the voltage sensor 51, and detects whether or not an abnormality has occurred in the second system 120 based on the voltage value of the voltage sensor 52. In other words, the control unit 31 uses abnormality detection control to identify whether the location where the abnormality has occurred is the first system 110 or the second system 120 (or both).

For example, as shown in FIG. 2, when no abnormality occurs in either the first system 110 or the second system 120, the control unit 31 turns on the inter-system switch 4 and turns off the power switch 22. In other words, the control returns from abnormality detection control to normal control.

In this way, when the voltage value of the voltage sensor 51 drops during normal control, the control unit 31 temporarily turns on the power switch 22 as shown in FIG. 2 to check for the presence or absence of an abnormality in the second system 120 using the power of the second power source 20. In this disclosure, the amount of decrease in the power of the second power source 20 due to the confirmation of an abnormality in the second system 120 is stored, and the stored information on the amount of decrease is used for various controls such as charging control, but details of this point will be described later.

Note that if an abnormality occurs only in the first system 110 during the abnormality detection control, the abnormality detection control will be switched to the evacuation drive control shown in Figure 3.

Figure 3 is a diagram showing an example of the operation of the evacuation driving control. The evacuation driving control is a driving control for evacuating and stopping the vehicle during autonomous driving to a safe place such as the shoulder of the road, since redundancy of the power supply during autonomous driving is no longer guaranteed when an abnormality occurs in the first system 110 or the second system 120.

As shown in FIG. 3, when an abnormality occurs in the first system 110, the control unit 31 keeps the inter-system switch 4 off and keeps the power switch 22 on. Then, the control unit 31 stops the power supply from the first power source 10 to the first load 101 and continues the power supply from the second power source 20 to the second load 102. In other words, when an abnormality occurs in the first system 110, the control unit 31 performs evacuation driving control using only the power of the second power source 20.

For this reason, the remaining charge in the second power source 20 needs to ensure the amount of power required for the evacuation driving control. However, as shown in FIG. 2, the second power source 20 also consumes power for the abnormality detection control, so there is a risk that the amount of power required for the evacuation driving control may fall below the amount of power required for the evacuation driving control depending on the amount of power reduction in the second power source 20 due to the abnormality detection control.

As shown in FIG. 2, the power supply device 1 according to the embodiment stores the amount of power reduction of the second power supply 20 due to the abnormality detection control in the storage unit 32. Specifically, the control unit 31 stores the amount of power reduction of the second power supply 20 when no abnormality occurs in either the first system 110 or the second system 120 during the abnormality detection control. For example, the control unit 31 stores the amount of voltage reduction of the voltage sensor 52 from the start of the abnormality detection control until the return to normal control. Specifically, the control unit 31 stores the amount of voltage reduction of the voltage sensor 52 from the time the power supply switch 22 is turned on following the start of the abnormality detection control until the time the power supply switch 22 is turned off following the return to normal control.

In the example shown in FIG. 2, when the remaining charge (SOC: State Of Charge) of the second power source 20 drops from 80% to 77%, the difference between the voltage value corresponding to 80% SOC and the voltage value corresponding to 77% SOC is stored as the amount of drop. Furthermore, the information on the amount of drop is not limited to the difference in voltage values, and may be the difference in SOC.

The storage unit 32 in which the information on the amount of decrease is stored may be a storage unit 32 built into the power supply device 1, or may be an external storage unit connected to the power supply device 1. The control unit 31 then uses the stored information on the amount of decrease to control charging of the second power source 20 shown in FIG. 4.

Figure 4 is a diagram showing an example of the operation of charging control. Charging control is control for charging the LiB21 of the second power source 20 from the generator described above via the DC/DC 11 of the first power source 10. As shown in Figure 4, when performing charging control, the control unit 31 turns on the system switch 4 and the power switch 22. As a result, power is supplied from the first power source 10 to the second power source 20, and the LiB21 is charged.

The control unit 31 also charges the LiB 21 to a remaining storage level determined based on the information on the amount of decrease described above and the required power, which is the drive power required to drive the second load 102 during the evacuation driving control. In the example shown in FIG. 4, the required power of the second load 102 is 80%, and the amount of decrease during the abnormality detection control is 3%.

In such a case, the control unit 31 controls the charging so that the required power of the second load 102 is at least 83%, which is 80% plus 3% of the reduction amount. Specifically, the control unit 31 performs charging control until the voltage value of the voltage sensor 52 becomes equal to or higher than the voltage value corresponding to 83% of the SOC.

In this way, by charging while taking into account the amount of power drop during abnormality detection control, even when switching from abnormality detection control to evacuation driving control, evacuation driving control can be reliably performed without causing a power shortage in LiB21 during evacuation driving. In other words, according to the power supply device 1 according to the embodiment, charging control of the second power source 20 can be performed while taking into account the process of identifying the abnormality (abnormality detection control).

In the above description, the control unit 31 stores information on the amount of decrease measured during abnormality detection control in the storage unit 32 and uses the information for charging control. However, for example, the amount of decrease obtained in advance through an experiment or the like may be stored in the storage unit 32 as an initial value, and the initial value may be updated. Specifically, the control unit 31 updates the initial value based on the actual value of the amount of decrease measured when abnormality detection control is performed. For example, the control unit 31 stores a simple average or weighted average of the initial value and the actual value as the final amount of decrease. Alternatively, the control unit 31 replaces the initial value with the actual value and stores it. The control unit 31 performs such an update process each time the actual value is measured.

This allows the change in the amount of degradation due to aging of the memory unit 32 and the change in the power usage of the abnormality detection control to be taken into account in the amount of degradation, thereby improving the accuracy of the amount of degradation stored. Furthermore, by storing an initial value of the amount of degradation, charging control can be performed that takes into account the amount of degradation (initial value) even before the actual value is measured by the abnormality detection control.

Next, using FIG. 5, we will explain an example of notifying the vehicle control device 100 of the possibility of autonomous driving based on the information on the amount of decrease described above.

Figure 5 is a diagram showing an example of the operation for notifying whether autonomous driving is possible. In Figure 5, the current remaining charge in LiB21 is 82%, and the combined value of the required power and the decrease amount is 83%.

In other words, in the example shown in FIG. 5, the current remaining amount of stored power in LiB21 is less than the combined value of the required power and the amount of decrease, so when switching from abnormality detection control to evacuation driving control using the second power source 20, there is a risk that evacuation driving control cannot be completed due to a lack of power.

For this reason, when the current remaining amount of stored power in LiB21 is less than the combined value of the required power and the amount of decrease, the control unit 31 notifies the vehicle control device 100 that autonomous driving control is not possible.

When the current remaining charge of the LiB 21 becomes 83% or more as a result of subsequent charging control, the control unit 31 notifies the vehicle control device 100 of permission to perform control in automatic driving. In other words, when the voltage of the second power source 20 is equal to or higher than the driving voltage (voltage according to the required power) plus the amount of drop, the control unit 31 notifies the vehicle control device 100 of permission to permit automatic driving. As a result, the vehicle control device 100 performs automatic driving only when a permission notification is received from the power supply device 1, thereby making it possible to accurately avoid a situation in which evacuation driving control during automatic driving cannot be completed due to a lack of power.

In addition, FIG. 5 shows an example of notifying the vehicle control device 100 of whether autonomous driving is possible, that is, an example of determining whether autonomous driving is possible and notifying the vehicle control device 1, but the vehicle control device 100 may determine whether autonomous driving is possible. This point will be explained using FIG. 6.

Figure 6 is a diagram showing an example of the operation of the vehicle control device 100 to determine whether autonomous driving is possible. As shown in Figure 6, the control unit 31 notifies the vehicle control device 100 of information on the amount of decrease. The vehicle control device 100 also grasps in advance the power required during evacuation driving control. The vehicle control device 100 then detects (or obtains from the control unit 31) the remaining amount of stored power in the LiB 21, and determines whether autonomous driving is possible based on the detected information on the remaining amount of stored power, the required power, and the amount of decrease.

This eliminates the need for the control unit 31 to determine whether autonomous driving is possible, thereby reducing the processing load on the control unit 31.

Next, the procedure of the process executed in the power supply device 1 according to the embodiment will be described with reference to FIG. 7. FIG. 7 is a flowchart showing the procedure of the process executed by the power supply device 1 according to the embodiment.

As shown in FIG. 7, first, it is assumed that the control unit 31 is performing normal control during automatic driving (step S101).

Then, the control unit 31 determines whether or not a voltage abnormality (voltage drop) has occurred in the first power source 10 or the second power source 20, i.e., a power failure has occurred in the first system 110 or the second system 120, based on the voltage values of the voltage sensors 51 and 52 (step S102). If a voltage abnormality (voltage drop) has not occurred in the first power source 10 or the second power source 20 (step S102: No), the control unit 31 proceeds to step S101.

If a voltage abnormality (voltage drop) occurs in the first power source 10 or the second power source 20 (step S102: Yes), the control unit 31 switches from normal control to abnormality detection control by turning off the inter-system switch 4 and turning on the power source switch 22 (step S103).

Next, the control unit 31 determines whether an abnormality has occurred in the first system 110 or the second system 120 through abnormality detection control (step S104).

If an abnormality is detected in one of the first system 110 and the second system 120 (step S104: Yes), the control unit 31 switches from abnormality detection control to evacuation driving control using the other normal system (step S105) and ends the process.

On the other hand, if there is no abnormality in either the first system 110 or the second system 120 (step S104: No), the control unit 31 returns to normal control by turning on the inter-system switch 4 and turning off the power supply switch 22 (step S106), stores the amount of voltage drop in the second power supply 20 due to the abnormality detection control in the memory unit 32 (step S107), and returns to step S101.

Next, the procedure of the charge control process executed in the power supply device 1 according to the embodiment will be described with reference to FIG. 8. FIG. 8 is a flowchart showing the procedure of the charge control process executed by the power supply device 1 according to the embodiment.

As shown in FIG. 8, the control unit 31 is performing charging control (step S201). Next, the control unit 31 determines whether the voltage value of the voltage sensor 52 has reached a voltage that takes into account the amount of decrease described above (step S202). Specifically, the control unit 31 determines whether the voltage value has reached a voltage that corresponds to the sum of the required power of the second load 102 and the amount of decrease.

When the voltage taking into account the amount of decrease has been reached (step S202: Yes), the control unit 31 notifies the vehicle control device 100 that automatic driving is permitted (step S203) and ends the process.

On the other hand, if the voltage taking into account the amount of decrease has not been reached (step S202: No), the control unit 31 notifies the vehicle control device 100 that autonomous driving is not possible (step S204) and executes step S202 again.

As described above, the power supply device 1 according to the embodiment includes a first system 110, a second system 120, an inter-system switch 4, a power switch 22, and a control unit 31. The first system 110 supplies power from the first power source 10 to the first load 101. The second system 120 supplies power from the second power source 20 to the second load 102. The inter-system switch 4 connects or disconnects the first system 110 and the second system 120. The power switch 22 connects or disconnects the second power source 20 and the second system 120. When the first system 110 and the second system 120 are normal, the control unit 31 performs normal control by connecting the system switch 4 and disconnecting the power switch 22, and when a power failure of the first system 110 or the second system 120 is detected, the control unit 31 performs abnormality detection control by disconnecting the system switch 4 and connecting the power switch 22 to detect an abnormality of the first system 110 or the second system 120. When no abnormality of the first system 110 or the second system 120 is detected by the abnormality detection control, the control unit 31 switches to normal control and stores the amount of voltage drop of the second power source 20 caused by the abnormality detection control in the storage unit 32, and when charging the second power source 20, charges the second power source 20 until the voltage becomes equal to or higher than the driving voltage required to drive the second load 102 plus the amount of drop. This allows charging control to be performed with the process of identifying the abnormality taken into account.

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

Reference Signs List 1 Power supply device 3 Control unit 4 System switch 10 First power supply 11 DC/DC converter 12 Lead battery 20 Second power supply 21 Lithium ion battery 22 Power supply switch 31 Control unit 32 Memory units 51, 52 Voltage sensor 100 Vehicle control device 101 First load 102 Second load 110 First system 120 Second system S Automatic driving system

Claims (4)

a first system in which electric power from a first power source is supplied to a first load including at least one of a steering motor and an electric brake ;
a second system in which the power of the second power source is supplied to a second load including at least one of a steering motor and an electric brake ;
an inter-system switch that connects or disconnects the first system and the second system;
a power supply switch that connects or disconnects the second power supply and the second system;
a control unit that performs normal control to connect the inter-system switch and turn off the power supply switch when the first system and the second system are normal, and that performs abnormality detection control to detect an abnormality in the first system or the second system based on the voltages of the first system and the second system by turning off the inter-system switch and connecting the power supply switch when a power failure in the first system or the second system is detected based on the voltages of the first system and the second system;
Equipped with
The control unit is
when no abnormality is detected in the first system and the second system by the abnormality detection control, switching to the normal control, and storing in a storage unit, at that time, an amount of voltage drop in the second system until the power switch is connected and cut off , as an amount of voltage drop in the second power source;
a power supply device comprising : a power supply unit configured to charge the second power supply until the second power supply becomes equal to or greater than a voltage obtained by adding the amount of decrease to a drive voltage corresponding to an amount of electric power required to drive the second load and complete evacuation travel control after the power supply failure is detected. The control unit is
When the abnormality is detected in the first system by the abnormality detection control, the second system supplies power to the second load, thereby performing an evacuation travel control during an automatic driving operation.
The power supply device according to claim 1 , wherein when the second power supply is equal to or higher than a voltage obtained by adding the driving voltage to the amount of decrease, a permission notification for permitting automatic driving is issued to a vehicle control device. The storage unit is
An initial value of the decrease amount is stored in advance,
The control unit is
3. The power supply device according to claim 1, wherein the initial value is updated based on an actual value of the amount of decrease measured when the abnormality detection control is performed. A power supply device according to any one of claims 1 to 3 ;
a vehicle control device that performs automatic driving by operating the first load and the second load;
Equipped with
The vehicle control device includes:
The automatic driving system allows the automatic driving when the voltage of the second power supply is equal to or higher than a voltage obtained by adding the amount of decrease to the driving voltage.

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