JP7638101B2 - Power supply device and control method - Google Patents

Description

The disclosed embodiments relate to a power supply device and a control method.

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 driven to a safe place and stopped even if a power failure occurs while the vehicle is running, and if 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).

Under normal circumstances, the redundant power supply system connects the inter-system switch to supply power from the first power supply to the first load and the second load. When a power supply failure such as a ground fault occurs in the first system, the redundant power supply system shuts off the inter-system switch to supply power from the second power supply to the second load, and then, when the power supply failure is resolved, reconnects the inter-system switch to supply power from the first power supply to the first load and the second load.

JP 2017-61240 A

However, in a redundant power supply system, if the inter-system switch is reconnected when there is a voltage difference between the first and second systems, the load may behave unnaturally, which may cause anxiety to users.

One aspect of the embodiment has been made in consideration of the above, and aims to provide a power supply device and a control method that can alleviate the anxiety of users when the behavior of the load may become unnatural.

A power supply device according to one aspect of the embodiment includes a first system, a second system, a control unit, and a command 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 is capable of disconnecting the first system and the second system. When the control unit detects a power failure in the first system or the second system, it shuts off the inter-system switch, and then, when the power failure is resolved, it reconnects the inter-system switch. When the inter-system switch is reconnected, the command unit notifies the user if the voltage difference between the first system and the second system is equal to or greater than a first predetermined value.

The power supply device and control method according to one aspect of the embodiment have the effect of relieving the user's anxiety when the load behavior may become unnatural.

FIG. 1 is an explanatory diagram illustrating an example of the configuration of a power supply device according to an embodiment. FIG. 2 is an explanatory diagram showing an example of the operation of the power supply device according to the embodiment. FIG. 3 is an explanatory diagram showing an example of the operation of the power supply device according to the embodiment. FIG. 4 is an explanatory diagram showing an example of the operation of the power supply device according to the embodiment. FIG. 5 is an explanatory diagram showing an example of the operation of the power supply device according to the embodiment. FIG. 6 is an explanatory diagram showing an example of the operation of the power supply device according to the embodiment. FIG. 7 is a flowchart illustrating an example of a process executed by the power supply device according to the embodiment.

Embodiments of a power supply device and a control method 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 following description will be given using an example of a power supply device that is mounted on a vehicle with an autonomous driving function and supplies power to a load, but the power supply device according to the embodiment may also be mounted on a vehicle that does not have an autonomous driving function.

[1. Power supply configuration]
As shown in FIG. 1 , a power supply device 1 according to the embodiment is connected to a first power source 10 , a first load 101 , a second load 102 , and an automatic driving control device 100 .

The first load 101 and the second load 102 include loads for 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 also includes general loads such as a display, an air conditioner, an audio device, a video device, and various lights.

The second load 102 includes at least devices that operate during autonomous driving, such as a steering motor, an electric brake device, an on-board camera, and a radar. The first load 101 and the second load 102 operate with power supplied from the power supply device 1. The autonomous driving control device 100 is a device that operates the first load 101 and the second load 102 to control the autonomous driving of the vehicle.

The first power source 10 includes a DC/DC converter (hereinafter referred to as "DC/DC11") and a lead battery (hereinafter referred to as "PbB12"). Note that the battery of the first power source 10 may be any secondary battery other than PbB12.

The DC/DC 11 is connected 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 includes a second power source 20, an inter-system switch 4, a control unit 31, and a command unit 32. The power supply device 1 further includes voltage sensors 51 and 52, and a current sensor 53. 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 includes a lithium ion battery (hereinafter referred to as "LiB21") and a battery switch 22. The battery switch 22 connects the LiB21 and the second load 102 in a manner that allows them to be 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 includes a first system 110 that supplies power from a first power source 10 to a first load 101, and a second system 120 that supplies power from a second power source 20 to a second load 102. A voltage sensor 51 is connected between the first power source 10 and the first load 101. The voltage sensor 51 detects the voltage value of the first system 110 and outputs the detection result to the control unit 31.

A voltage sensor 52 is connected between the second power source 20 and the second load 102. The voltage sensor 52 detects the voltage value of the second system 120 and outputs the detection result to the control unit 31. The inter-system switch 4 connects the first system 110 and the second system 120 in a manner that allows them to be disconnected.

A current sensor 53 is connected between the inter-system switch 4 and the first system 110. The current sensor 53 may be connected between the inter-system switch 4 and the second system 120. The current sensor 53 detects the current value of the current flowing through the inter-system switch 4 and outputs the detection result to the control unit 31.

The control unit 31 and the command unit 32 include a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and various other circuits. The control unit 31 and the command unit 32 may be configured with hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

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 controls the on/off of the inter-system switch 4 and the battery switch 22 based on the detection results input from the voltage sensors 51, 52 and the current sensor 53, and supplies power from the first power source 10 or the second power source 20 to the first load 101 and the second load 102.

When a power failure occurs in one of the first system 110 and the second system 120, the control unit 31 supplies power to the load through the other system. This allows the power supply device 1 to use the automatic driving control device 100 to evacuate the vehicle to a safe place and stop it.

The command unit 32 outputs various commands to the first load 101 and the second load 102 by the CPU executing a program stored in the ROM using the RAM as a working area. The command unit 32 outputs a notification command (described later) and a command to transition from normal mode to energy saving mode to the first load 101 and the second load 102 according to the state of the power supply device 1 input from the control unit 31.

2. Normal operation of the power supply
During normal operation when no power failure has occurred in the first system 110 and the second system 120, the control unit 31 connects the inter-system switch 4 and cuts off the battery switch 22 as shown in FIG. 2 to supply power from the first power source 10 to the first load 101 and the second load 102.

In such a power supply device 1, a ground fault may occur in the first system 110 or the second system 120 during normal operation. In the example shown in FIG. 3, a ground fault 200 has occurred in the first system 110. In such a case, the control unit 3 performs an operation to be performed when a ground fault occurs.

[3. Operation when a ground fault occurs]
The control unit 31 detects the occurrence of a ground fault 200 based on the detection result input from the current sensor 53. The control unit 31 detects that a ground fault has occurred in the first system 110 or the second system 120 when the current value detected by the current sensor 53 is an overcurrent exceeding a ground fault threshold value.

Furthermore, when an overcurrent flows from the second system 120 to the first system 110, the control unit 31 determines that a ground fault 200 has occurred in the first system 110. Furthermore, when an overcurrent flows from the first system 110 to the second system 120, the control unit 31 determines that a ground fault has occurred in the second system 120.

If a ground fault occurs and the inter-system switch 4 remains connected, the power stored in the first power source 10 and the second power source 20 will be discharged, making it impossible to evacuate the vehicle. Therefore, as shown in FIG. 3, when the control unit 31 detects, for example, a ground fault 200, which is a power failure in the first system 110, it shuts off the inter-system switch 4 and connects the battery switch 22 to supply power from the second power source to the second load 102.

This allows the automatic driving control device 100 to use the second load 102 to drive the vehicle to an evacuation site. If a ground fault is detected in the second system 120, the control unit 31 shuts off the system switch 4, keeps the battery switch 22 shut off, and supplies power from the first power source to the first load 101 to drive the vehicle to an evacuation site.

Note that a ground fault may be resolved over time. For example, if water droplets on the first system cause a ground fault by shorting to the earth, the ground fault will be resolved when the water droplets evaporate. For example, when the ground fault 200 in the first system 110 is resolved, the control unit 31 shuts off the battery switch 22 and reconnects the system switch 4 to return to normal operation.

However, when the power supply device 1 reconnects the system switch 4, the load behavior may become unnatural, which may cause anxiety to the user. Next, referring to FIG. 4, problems that may occur when the system switch 4 is reconnected will be described.

[4. Problems when reconnecting the grid switch]
4, for example, when the ground fault 200 in the first system 110 is eliminated, the control unit 31 turns off the battery switch 22 and reconnects the inter-system switch 4. This allows the power supply device 1 to supply power from the first power source 10 to the first load 101 and the second load 102, as in normal operation.

However, when the power supply device 1 reconnects the inter-system switch 4 while the voltage of the first system 110 is higher than the voltage of the second system 120, the voltage of the first system 110 temporarily drops, which may cause the behavior of the first load 101 to become unnatural.

For example, the display of the first load 101 may cause flickering in the displayed image. Also, the audio of the first load 101 may cause distorted sound. If the behavior of the first load 101 becomes unnatural in this way, the power supply device 1 may cause anxiety to the user.

The command unit 32 of the power supply device 1 eliminates the user's anxiety by outputting commands to the first load 101 and the second load 102 according to the state of the power supply device 1 when the system switch 4 is reconnected. Next, with reference to Figures 5 and 6, an example of the operation of the power supply device 1 that eliminates the user's anxiety will be described.

[5. Example of power supply device operation to eliminate user concerns]
5 , when reconnecting the inter-system switch 4, the control unit 31 acquires detection results from the voltage sensors 51 and 52 before reconnecting the inter-system switch 4. Then, the control unit 31 outputs the voltage difference between the first system 110 and the second system 120 to the command unit 32.

For example, if the voltage of the first system 110 is higher than the voltage of the second system 120 and the voltage difference is equal to or greater than a first predetermined value (e.g., 0.5 V), the command unit 32 outputs a notification command to the display of the first load 101 to notify the user.

In response to the notification command, the display displays a notification message such as "The screen will flicker temporarily from now on." The control unit 31 then turns off the battery switch 22 and connects the system switch 4. In this way, the power supply device 1 can alleviate the user's anxiety by notifying the user in advance that the behavior of the first load 101 will become unnatural.

In addition, if the voltage difference between the first system 110 and the second system 120 is equal to or greater than a first predetermined value, the command unit 32 outputs an energy saving mode transition command to at least one of the first load 101 and the second load 102.

The energy saving mode transition command is a command to transition the operation mode of the load to an energy saving mode that consumes less power than the normal mode. The energy saving mode includes a mode in which each load performs the minimum necessary operation. The energy saving mode also includes a mode in which a specific load among the loads stops operating.

For example, when the first load 101 transitions to the energy saving mode, it is able to operate at a lower voltage than in the normal mode. Therefore, even if the inter-system switch 4 is subsequently connected and the voltage of the first system 110 temporarily drops, unnatural behavior can be prevented.

Specifically, when the display of the first load 101 transitions to the energy saving mode, the brightness of the display screen is lowered below the brightness in the normal mode. This prevents flickering on the display screen even if the voltage of the first system 110 temporarily drops.

In addition, even if some flickering occurs on the display screen, the brightness is kept low, so the flickering is unlikely to be noticed by the user. Therefore, the power supply device 1 can eliminate the user's concerns.

In addition, in the power supply device 1, when the second load 102 transitions to the energy saving mode, when the inter-system switch 4 is subsequently connected, the current diverted from the first system 110 to the second system 120 becomes smaller than when the second load 102 is in the normal mode.

As a result, when the system switch 4 is connected, the power supply device 1 can suppress a reduction in the power supplied to the first load 101, thereby preventing the first load 101 from behaving unnaturally.

Here, we have described a case in which when the inter-system switch 4 is reconnected, if the voltage difference between the first system 110 and the second system 120 is equal to or greater than the first predetermined value, the command unit 32 outputs a notification command and an energy saving mode transition command, but this is just one example.

The command unit 32 may be configured to output either a notification command or an energy saving mode transition command if the voltage difference between the first system 110 and the second system 120 is equal to or greater than a first predetermined value when the system switch 4 is reconnected.

In addition, in the power supply device 1, when the inter-system switch 4 is connected, the voltage difference between the first system 110 and the second system 120 may be equal to or greater than a second predetermined value (e.g., 3 V) that is greater than the first predetermined value.

In this case, the control unit 31 controls at least one of the first power source 10, the second power source 20, the first load 101, and the second load 102 so that the voltage difference between the first system 110 and the second system 120 is reduced.

For example, when the voltage of the first system 110 is higher than the voltage of the second system 120 and the voltage difference is equal to or greater than a second predetermined value, the control unit 31 performs step-down control on the DC/DC 11 of the first power source 10 to reduce the output voltage. This allows the control unit 31 to reduce the voltage difference between the first system 110 and the second system 120.

In addition, when the voltage of the first system 110 is higher than the voltage of the second system 120 and the voltage difference is equal to or greater than a second predetermined value, the control unit 31 can output a power consumption command to the first load 101 via the command unit 32. When the amount of power consumed by the first load 101 increases, the voltage of the first system 110 decreases. This allows the control unit 31 to reduce the voltage difference between the first system 110 and the second system 120.

In addition, in the power supply device 1, when the inter-system switch 4 is connected, the voltage of the second system 120 may be higher than the voltage of the first system 110, and the voltage difference may be equal to or greater than a second predetermined value. In this case, as shown in FIG. 6, the control unit 31 performs boost control on the DC/DC 11 of the first power source 10 to increase the output voltage. This allows the control unit 31 to reduce the voltage difference between the first system 110 and the second system 120.

In addition, when the voltage of the second system 120 is higher than the voltage of the first system 110 and the voltage difference is equal to or greater than a second predetermined value, the control unit 31 can output a power consumption command to the second load 102 via the command unit 32. When the amount of power consumed by the second load 102 increases, the voltage of the second system 120 decreases. This allows the control unit 31 to reduce the voltage difference between the first system 110 and the second system 120.

When the voltage difference between the first system 110 and the second system 120 becomes less than a second predetermined value, the command unit 32 outputs, for example, a notification command to the display of the first load 101 to notify the user. In accordance with the notification command, the display displays a notification message such as, for example, "The screen will flicker temporarily from now on."

Then, the control unit 31 turns off the battery switch 22 and turns on the system switch 4. This allows the power supply device 1 to eliminate the user's anxiety caused by display flickering.

In addition, when the voltage difference between the first system 110 and the second system 120 becomes less than a second predetermined value, the command unit 32 outputs an energy saving mode transition command to at least one of the first load 101 and the second load 102. This allows the power supply device 1 to suppress unnatural behavior of the load or to make the unnatural behavior less noticeable to the user, thereby eliminating the user's anxiety.

[6. Processing performed by the power supply device]
Next, an example of the process executed by the power supply device 1 will be described with reference to Fig. 7. The power supply device 1 repeatedly executes the process shown in Fig. 7 while the vehicle is powered on. As shown in Fig. 7, the control unit 31 first determines whether or not a power failure of the first system 110 or the second system 120 has been detected (step S101).

When the control unit 31 determines that a power failure has not been detected (step S101, No), it ends the process and restarts the process from step S101. When the control unit 31 determines that a power failure has been detected (step S101, Yes), it turns off the system switch 4 (step S102). At this time, if the control unit 31 detects a power failure in the first system 110, it connects the battery switch 22. If the control unit 31 detects a power failure in the second system 120, it keeps the battery switch S22 turned off.

Then, the control unit 31 determines whether the power failure has been resolved based on the detected voltage of the voltage sensor 51 or the voltage sensor 52 (step S103). That is, if the first system 110 has failed, it is determined that the power failure has been resolved if the voltage of the first system 110 detected by the voltage sensor 51 has recovered to a predetermined value or higher. If the second system 120 has failed, it is determined that the power failure has been resolved if the voltage of the second system 120 detected by the voltage sensor 52 has recovered to a predetermined value or higher. If the control unit 31 determines that the power failure has not been resolved (step S103, No), it determines whether a predetermined time has elapsed (step S110).

When the control unit 31 determines that the predetermined time has elapsed (step S110, Yes), it prohibits the automatic driving control device 100 from performing automatic driving control (step S111), ends the processing, and starts the processing again from step S101.

If the control unit 31 determines that the predetermined time has not elapsed (step S110, No), the process proceeds to step S103. If the control unit 31 determines that the power failure has been resolved (step S103, Yes), the control unit 31 determines whether the voltage difference between the first system 110 and the second system 120 is equal to or greater than a second predetermined value (step S104).

When the control unit 31 determines that the voltage difference is not equal to or greater than the second predetermined value (step S104, No), the process proceeds to step S106. When the control unit 31 determines that the voltage difference is equal to or greater than the second predetermined value (step S104, Yes), the control unit 31 controls at least one of the first power source 10, the second power source 20, the first load 101, and the second load 102 so as to reduce the voltage difference (step S105).

Then, the command unit 32 determines whether the voltage difference between the first system 110 and the second system 120 is within a range of equal to or greater than the first predetermined value and less than the second predetermined value (step S106). If the command unit 32 determines that the voltage difference is not within a range of equal to or greater than the first predetermined value and less than the second predetermined value (step S106, No), it determines whether the voltage difference is less than the first predetermined value (step S112).

If the command unit 32 determines that the voltage difference is less than the first predetermined value (step S112, Yes), the process proceeds to step S109. If the command unit 32 determines that the voltage difference is not less than the first predetermined value (step S112, No), the process proceeds to step S105.

When the command unit 32 determines that the voltage difference is within a range of equal to or greater than the first predetermined value and less than the second predetermined value (Yes in step S106), the command unit 32 issues a notification command to the display of the first load 101 (step S107). Then, the command unit 32 issues a transition command to transition at least one of the first load 101 and the second load 102 from the normal mode to the energy saving mode (step S108).

The order of the processes in steps S107 and S108 may be reversed. Also, the command unit 32 may perform only one of the processes in steps S107 and S108.

Then, the control unit 31 reconnects the system switch 4 (step S109). At this time, if the control unit 31 has connected the battery switch 22 in step S102, the control unit 31 disconnects the battery switch 22 in step S109. Then, the control unit 31 ends the process and starts the process again from step S101.

Note that the reconnection of the inter-system switch 4 in step S109 may be performed when the vehicle is stopped. If the inter-system switch 4 is reconnected while the vehicle is traveling, control will switch from the load of one system to the load of both systems, which may affect driving behavior.

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.

1 Power supply device 10 First power supply 11 DC/DC
12 PbB
20 Second power supply 21 LiB
22 Battery switch 31 Control unit 32 Command unit 4 Inter-system switch 51, 52 Voltage sensor 53 Current sensor 100 Automatic operation control device 101 First load 102 Second load 110 First system 120 Second system

Claims (6)

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;
an inter-system switch capable of connecting and disconnecting the first system and the second system;
a control unit that, when detecting a power failure in the first system or the second system, shuts off the inter-system switch, and thereafter, when the power failure is eliminated, reconnects the inter-system switch;
and a command unit that notifies a user if a voltage difference between the first system and the second system is equal to or greater than a first predetermined value when the inter-system switch is reconnected. The control unit is
When the voltage difference is equal to or greater than a second predetermined value that is greater than the first predetermined value, at least one of the first power source, the second power source, the first load, and the second load is controlled so as to reduce the voltage difference;
The command unit includes:
The power supply device according to claim 1 , wherein the notification is made when the voltage difference becomes less than the second predetermined value. 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;
an inter-system switch capable of connecting and disconnecting the first system and the second system;
a control unit that, when detecting a power failure in the first system or the second system, shuts off the inter-system switch, and thereafter, when the power failure is eliminated, reconnects the inter-system switch;
a command unit that switches an operation mode of at least one of the first load and the second load to an energy saving mode having lower power consumption than a normal mode when a voltage difference between the first system and the second system is equal to or greater than a first predetermined value when the inter-system switch is reconnected ,
The control unit is
When the voltage difference is equal to or greater than a second predetermined value that is greater than the first predetermined value, at least one of the first power source, the second power source, the first load, and the second load is controlled so as to reduce the voltage difference;
The command unit includes:
When the voltage difference becomes less than the second predetermined value, the power supply device transitions the operation mode to the energy saving mode . 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;
an inter-system switch capable of connecting and disconnecting the first system and the second system;
a control unit that, when detecting a power failure in the first system or the second system, shuts off the inter-system switch, and thereafter, when the power failure is eliminated, reconnects the inter-system switch;
and a command unit that, when the inter-system switch is reconnected and the voltage of the first system is higher than the voltage of the second system, transitions an operation mode of the first load to an energy saving mode that consumes less power than a normal mode. The first load includes at least one load of a display, an air conditioner, an audio device, a video device, and a light device in addition to a load that operates during autonomous driving;
The second load includes a load that operates during automatic driving.
5. The power supply device according to claim 1, wherein the power supply device is a power supply unit. 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;
a system switch capable of connecting and disconnecting the first system and the second system,
A control unit of the power supply device
When a power failure in the first system or the second system is detected, the inter-system switch is cut off, and when the power failure is eliminated, the inter-system switch is reconnected;
A notification unit of the power supply device
and when the inter-system switch is reconnected, if a voltage difference between the first system and the second system is equal to or greater than a first predetermined value, notifying a user.

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