JP2023038754A - Power supply control device and power supply control method - Google Patents

Abstract

To provide a power supply control device and a power supply control method which can prevent influence of an earth fault caused in a second system from reaching a first system.SOLUTION: A power supply control device according to an embodiment comprises a first system, a second system, an inter-system switch and a control part. The first system supplies electric power of a first power supply to a first load, and the second system supplies electric power of a second power supply to a second load. The inter-system switch connects the first system to the second system. The control part turns on the inter-system switch at normal times in automatic operation and in non-automatic operation, and turns off the inter-system switch when detecting an earth fault of the first system or of the second system. The control part, when a voltage of the second power supply becomes a predetermined voltage or lower at the normal times in the non-automatic operation, turns off the inter-system switch.SELECTED DRAWING: Figure 1

Description

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

Conventionally, a first system that supplies power from a first power supply to a first load, a second system that supplies power from a second power supply to a second load, and an inter-system switch that connects the first system and the second system , a redundant power supply system that includes a battery switch that connects a second power supply to a second system (see, for example, Patent Document 1).

The redundant power system normally turns on the battery switch and the grid switch. When the redundant power supply system detects a ground fault in the first system or the second system, the switch between systems is turned off, and the normal one of the first system and the second system in which the ground fault is not detected operates the FOP. (fail operation).

JP 2019-62727 A

However, if a ground fault occurs in the second system while the inter-system switch is on, the first system is affected.

One aspect of the embodiments has been made in view of the above, and provides a power supply control device and a power supply control method that can prevent the first system from being affected by a ground fault that has occurred in the second system. intended to

A power supply control device according to an aspect of an embodiment includes a first system, a second system, an inter-system switch, and a control unit. The first system supplies power from the first power supply to the first load. The second system supplies power from the second power supply to the second load. An inter-system switch connects the first system and the second system. The control unit turns on the inter-system switch during normal operation during automatic operation and during non-automatic operation, and turns off the inter-system switch when detecting a ground fault in the first system or the second system. The control unit turns off the inter-system switch when the voltage of the second power supply drops below a predetermined voltage during normal non-automatic operation.

A power supply control device and a power supply control method according to an aspect of an embodiment have the effect of being able to prevent the first system from being affected by a ground fault that has occurred in the second system.

FIG. 1 is an explanatory diagram illustrating a configuration example of a power control device according to an embodiment. FIG. 2 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment. FIG. 3 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment. FIG. 4 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment. FIG. 5 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment. FIG. 6 is an explanatory diagram showing an operation example of the power supply control device according to the embodiment. FIG. 7 is an explanatory diagram illustrating an operation example of the power supply control device according to the embodiment; FIG. 8 is an explanatory diagram illustrating an operation example of the power supply control device according to the embodiment; 9 is a flowchart illustrating an example of processing executed by a control unit of the power control device according to the embodiment; FIG.

Embodiments of a power control device and a power control method will be described in detail below with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below. In the following, a power supply control device installed in a vehicle equipped with an automatic driving function and supplying electric power to a load will be described as an example. may be

In the following description, the vehicle in which the power control device is mounted is an electric vehicle or a hybrid vehicle, but the vehicle in which the power control device is mounted may be an internal combustion engine driven vehicle.

Note that the power supply control device according to the embodiment includes a first power supply and a second power supply, and when a power supply failure occurs in either one of the first power supply and the second power supply system, the other power supply system may be installed in any device that backs up the first power supply by

[1. Configuration of power supply control device]
FIG. 1 is an explanatory diagram illustrating a configuration example of a power control device according to an embodiment. As shown in FIG. 1, the power control device 1 according to the embodiment is connected to a first power source 10, a first load 101, a general load 102, a second load 103, and an automatic operation control device 100. . The power supply control device 1 includes a first system 110 that supplies power from a first power supply 10 to a first load 101 and a general load 102, and a second system 120 that supplies power from a second power supply 20, which will be described later, to a second load 103. and

The first load 101 includes a load for automatic operation. For example, the first load 101 includes a steering motor that operates during automatic driving, an electric brake device, an in-vehicle camera, and the like. General loads 102 include, for example, displays, air conditioners, audio, video, and various lights.

The second load 103 has some of the functions for automatic operation that the first load 101 has. For example, the second load 103 includes the minimum necessary devices for the FOP, such as a steering motor, an electric brake device, and a radar. The first load 101 , the general load 102 and the second load 103 operate with power supplied from the power control device 1 .

The automatic driving control device 100 is a device for controlling automatic driving of a vehicle. The automatic driving control device 100 operates the first load 101 and the second load 103 to drive the vehicle by automatic driving. Further, the automatic operation control device 100 can perform FOP by the second load 103 when a ground fault occurs in the first system 110 during automatic operation, and when a ground fault occurs in the second system 120 , the FOP can be implemented by the first load 101 .

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

DC/DC 11 is connected to a generator and a high-voltage battery having a higher voltage than PbB 12 , steps down the voltage of the generator and high-voltage battery, and outputs the voltage to first system 110 . A generator is, for example, an alternator that converts the kinetic energy of a running vehicle into electricity to generate electricity. A high-voltage battery is, for example, a battery for driving a vehicle mounted on an electric vehicle or a hybrid vehicle.

When the first power supply 10 is installed in an engine vehicle, an alternator (generator) is provided instead of the DC/DC 11 . The DC/DC 11 charges the PbB 12, supplies power to the first load 101 and the general load 102, supplies power to the second load 103, and charges the second power supply 20, which will be described later.

The power supply control device 1 includes a second power supply 20 , an inter-system switch 41 , a battery switch 42 , a control section 3 , a first voltage sensor 51 and a second voltage sensor 52 . The second power supply 20 is a backup power supply when the first power supply 10 cannot supply power. The second power source 20 includes a lithium ion battery (hereinafter referred to as "LiB21"). The battery of the second power supply 20 may be any secondary battery other than LiB21.

Inter-system switch 41 is provided in inter-system line 130 that connects first system 110 and second system 120 , and is a switch capable of connecting and disconnecting first system 110 and second system 120 . The battery switch 42 is a switch that connects the second power supply 20 to the second system 120 .

The first voltage sensor 51 is provided in the first system 110 to detect the voltage of the first system 110 and output the detection result to the control unit 3 . Second voltage sensor 52 is provided in second system 120 , detects the voltage of second system 120 , and outputs the detection result to control unit 3 .

The control unit 3 includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various circuits. Note that the control unit 3 may be configured by hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

The control unit 3 controls the operation of the power supply control device 1 by causing the CPU to execute programs stored in the ROM using the RAM as a work area. When activated, the control unit 3 turns on the inter-system switch 41 and turns off the battery switch 42 .

Control unit 3 detects a ground fault in first system 110 or second system 120 based on the detection results input from first voltage sensor 51 and second voltage sensor 52 . The control unit 3 turns on the inter-system switch 41 during normal operation during automatic operation and non-automatic operation, and turns off the inter-system switch 41 when detecting a ground fault in the first system 110 or the second system 120 . A specific example of the ground fault detection method by the control unit 3 will be described later.

When the ground fault in the first system 110 or the second system 120 is detected, the control unit 3 notifies the automatic operation control device 100 to that effect. When the control unit 3 detects a ground fault in the first system 110 or the second system 120, the control unit 3 outputs to the automatic operation control device 100 an automatic operation prohibition signal indicating that automatic operation is impossible. In addition, when the control unit 3 does not detect a ground fault in the first system 110 or the second system 120, it outputs an automatic operation permission signal indicating that automatic operation is possible to the automatic operation control device 100. .

Further, when the voltage of the second power supply 20 becomes equal to or lower than a predetermined voltage, the control unit 3 outputs an automatic operation prohibition signal to the automatic operation control device 100 indicating that the automatic operation is disabled. The predetermined voltage here is the minimum voltage of the second power supply 20 required for backing up the first power supply 10 . Also, the voltage of the second power supply 20 and the predetermined voltage here include the concept of SOC (State Of Charge). For example, the predetermined voltage is a voltage corresponding to SOC 80%. It should be noted that this predetermined voltage is greater than a threshold value for ground fault determination, which will be described later.

The second power supply 20 includes a measuring device (not shown) that detects the voltage of the LiB 21 and outputs the detection result to the control unit 3 . If the battery switch 42 is off when measuring the voltage of the second power supply 20, the control unit 3 cannot measure the voltage of the second power supply 20 because the current does not flow through the LiB 21. Therefore, at least the battery switch 42 is turned off. It is turned on to make the voltage of LiB 21 detectable.

After that, the control unit 3 instructs the measuring device of the second power supply 20 to measure the voltage of the LiB 21 through communication, acquires the voltage information of the LiB 21 from the measuring device, and detects the SOC of the LiB 21 .

When a power failure such as a ground fault occurs in the first system 110 , the control unit 3 turns off the inter-system switch 41 and turns on the battery switch 42 to switch the second power supply 20 to the second load 103 . to power the Further, when a power failure such as a ground fault occurs in the second system 120, the control unit 3 turns off the inter-system switch 41 and turns off the battery switch 42, thereby switching from the first power supply 10 to the first power supply. Power is supplied to one load 101 and general load 102 .

As a result, even if one of the systems has a ground fault during automatic operation, the power supply control device 1 uses the other system, and the automatic operation control device 100 causes the vehicle to evacuate to a safe place. operation) to stop the vehicle. Next, the operation of the power control device 1 will be described with reference to FIGS. 2 to 8. FIG.

[2. Normal Operation of Power Control Device]
As shown in FIG. 2, the control unit 3 turns off the battery switch 42, turns on the inter-system switch 41, and turns on the first system 110 and the second system 120 when no ground fault occurs. Power is supplied from one power supply 10 to a first load 101 , a general load 102 and a second load 103 . The control unit 3 outputs an automatic operation permission signal to the automatic operation control device 100 when the voltage of the second power supply 20 is higher than the predetermined voltage in the normal time when no ground fault occurs. In this case, the driver of the vehicle can select either automatic driving by the automatic driving control device 100 or non-automatic driving by manual operation.

[3. Operation of Power Supply Control Device When Ground Fault Occurs]
Next, the operation of the power supply control device 1 when a ground fault occurs will be described with reference to FIGS. 3 to 6. FIG. As shown in FIG. 3, in the power supply control device 1, for example, when a ground fault 200 occurs in the first system 110 or when a ground fault 201 occurs in the second system 120, an overload is directed toward the ground fault point. Since the current flows, the voltage detected by the first voltage sensor 51 and the second voltage sensor 52 becomes equal to or less than the ground fault threshold.

Therefore, when the voltage detected by the second voltage sensor 52 becomes equal to or less than the ground fault threshold, the control unit 3 provisionally determines that the ground fault 200 or 201 has occurred in the first system 110 or the second system 120. and outputs an automatic operation prohibition signal to the automatic operation control device 100 . When the controller 3 provisionally determines that the ground faults 200 and 201 have occurred, it turns off the inter-system switch 41 and turns on the battery switch 42 . As a result, the connection between the first system 110 and the second system 120 is cut, power is supplied from the first power supply 10 to the first system 110 , and power is supplied from the second power supply 20 to the second system 120 .

Note that the control unit 3 controls the grounding of the first system 110 or the second system 120 when the voltage detected by at least one of the first voltage sensor 51 and the second voltage sensor 52 becomes equal to or less than the ground fault threshold. It is also possible to provisionally determine that a fault has occurred.

After that, the control unit 3 returns until the voltage detected by the first voltage sensor 51 is equal to or less than the ground fault threshold for a predetermined time or more and the voltage detected by the second voltage sensor 52 exceeds the ground fault threshold within a predetermined time. If so, it is determined that a ground fault 200 has occurred in the first system 110 .

In this case, as shown in FIG. 4, the control unit 3 continues to turn off the intersystem switch 41 and turn on the battery switch 42 to supply power from the second power supply 20 to the second load 103, and notify that effect. The automatic operation control device 100 is notified. As a result, the automatic driving control device 100 can operate the second load 103 with the electric power supplied from the second power supply 20 to make the vehicle evacuate to a safe place and stop the vehicle. In addition, the automatic operation control device 100 may be configured to start evacuation traveling when an automatic operation prohibition signal is input from the power supply control device 1 .

Further, after the control unit 3 provisionally determines that a ground fault has occurred in the first system 110 or the second system 120, the voltage detected by the second voltage sensor 52 is equal to or less than the ground fault threshold even after a predetermined time has passed. , and when the voltage detected by the first voltage sensor 51 recovers to exceed the ground fault threshold value within a predetermined time, it is officially determined that the ground fault 201 has occurred in the second system 120 .

In this case, as shown in FIG. 5 , the control unit 3 turns off the battery switch 42 while continuing to turn off the intersystem switch 41 to supply electric power from the first power supply 10 to the first load 101 . The automatic operation control device 100 is notified to that effect. As a result, the automatic driving control device 100 can operate the first load 101 with the electric power supplied from the first power supply 10 to make the vehicle evacuate to a safe place and stop the vehicle. In addition, the automatic operation control device 100 may be configured to start evacuation traveling when an automatic operation prohibition signal is input from the power supply control device 1 .

In addition, in the power supply control device 1, when the first load 101 or the general load 102 is temporarily overloaded instead of the ground faults 200 and 201, the voltage detected by the first voltage sensor 51 is temporarily may fall below the ground fault threshold. Further, in the power supply control device 1, when the second load 103 is temporarily overloaded, the voltage detected by the second voltage sensor 52 may temporarily fall below the ground fault threshold.

In this case, in the power supply control device 1 , power is continuously supplied from the first power supply 10 to the first load 101 and the general load 102 , and power is supplied from the second power supply 20 to the second load 103 . Therefore, control unit 3 temporarily determines that ground faults 200 and 201 have occurred in first system 110 or second system 120, and then controls first voltage sensor 51 and second voltage sensor 52 before a predetermined time elapses. If both of the voltages detected by and recover to exceed the ground fault threshold, it is a temporary voltage drop and it is determined that there is no abnormality in the power supply. After that, the control unit 3 turns off the battery switch 42 and turns on the system switch 41 again in order to return to the normal operation shown in FIG.

[4. Operation during manual operation of the power control device]
The LiB 21 of the second power supply 20 may not be able to secure the SOC required for automatic operation due to aged deterioration, low temperature, or the like. In this case, the output voltage of the second power supply 20 becomes equal to or lower than the predetermined voltage. Therefore, the control unit 3 outputs an automatic operation prohibition signal to the automatic operation control device 100 when the voltage of the second power supply 20 becomes equal to or lower than the predetermined voltage. As a result, if the vehicle is in non-automatic driving, subsequent automatic driving is prohibited, and if it is in automatic driving, the vehicle shifts to non-automatic driving. At this time, since no ground fault has occurred, the inter-system switch 41 remains on.

After that, as shown in FIG. 6, when the ground fault 201 occurs in the second system 120, the power supply control device 1 switches from the first power supply 10 to the ground fault point until the inter-system switch 41 is turned off. An overcurrent flowing toward the first load 101 and the second load 103 causes a voltage drop. Thus, if a ground fault occurs in the second system 120 while the inter-system switch 41 is on, the first system 110 is affected.

Therefore, the control unit 3 turns off the inter-system switch 41 when the voltage of the second power supply 20 becomes equal to or lower than the predetermined voltage during normal non-automatic operation. Specifically, as shown in FIG. 7, when the voltage of the second power supply 20 becomes equal to or less than a predetermined voltage and an automatic operation prohibition signal is output to the automatic operation control device 100, the control unit 3 turns off the inter-system switch 41. to When the inter-system switch 41 is turned off, power is no longer supplied to the second load 103, but the second load 103 is a load for automatic operation and the vehicle is in non-automatic operation. no.

As a result, even if a ground fault occurs in the second system 120 after that, the power supply control device 1 prevents the overcurrent flowing from the first power supply 10 toward the ground fault point because the inter-system switch 41 is turned off. does not occur, and voltage drop does not occur in the first load 101 and the second load 103 . Therefore, according to the power supply control device 1 , it is possible to prevent the first system 110 from being affected by the ground fault that has occurred in the second system 120 .

Note that the control unit 3 turns on the inter-system switch 41 and the battery switch 42 at startup, permits automatic operation, and then determines whether or not the voltage of the second power supply 20 is equal to or lower than a predetermined voltage. During this time, non-automated driving is permitted.

After that, when the voltage of the second power supply 20 becomes equal to or lower than the predetermined voltage during normal non-automatic operation, the control unit 3 turns off the inter-system switch 41 and the battery switch 42 . Thereby, the power supply control device 1 can prevent the voltage drop of the second power supply 20 even if the ground fault 201 occurs in the second system 120 when the voltage of the second power supply 20 is equal to or lower than the predetermined voltage.

When the voltage of the second power supply 20 is equal to or lower than the predetermined voltage, the control unit 3 turns on the inter-system switch 41 and the battery switch 42 while the vehicle is stopped, as shown in FIG. DC 11 charges the second power supply 20 . As a result, the power supply control device 1 can safely restore the voltage of the second power supply 20 .

After that, when the voltage of the second power supply 20 recovers to the target value exceeding the predetermined voltage and the charging of the second power supply 20 is completed, the control unit 2 turns off the battery switch 42 and causes the automatic operation control device 100 to operate automatically. A permission signal is output, and the normal state shown in FIG. 2 is entered. As a result, the power supply control device 1 can prevent discharge of the second power supply 20 during normal operation.

[5. Processing executed by the control unit]
Next, processing executed by the control unit 3 of the power control device 1 will be described with reference to FIG. FIG. 9 is a flowchart showing an example of processing executed by the control unit 3 of the power control device 1 according to the embodiment.

When the control unit 3 is activated, it first turns on the system switch 41 (step S101), turns on the battery switch 42 (step S102), outputs an automatic operation prohibition signal to the automatic operation control device 100, and automatically Driving is prohibited (step S103).

Subsequently, the control unit 3 acquires the voltage of the second power supply 20 through communication (step S104), and determines whether the voltage of the second power supply 20 is equal to or lower than a predetermined voltage (step S105). When the control unit 3 determines that the voltage of the second power supply 20 is not equal to or lower than the predetermined voltage (step S105, No), the battery switch 42 is turned off (step S113), and an automatic operation permission signal is sent to the automatic operation control device 100. Output, permit automatic operation (step S114), and terminate the process.

When the control unit 3 determines that the voltage of the second power supply 20 is equal to or lower than the predetermined voltage (step S105, Yes), the control unit 3 turns off the inter-system switch 41 (step S106) and turns off the battery switch 42 ( Step S107), it is determined whether or not the vehicle is stopped (step S108).

If the controller 3 determines that the vehicle is not stopped (step S108, No), the process proceeds to step S105. When the control unit 3 determines that the vehicle is stopped (step S108, Yes), it turns on the inter-system switch 41 (step S109), turns on the battery switch 42 (step S110), and turns on the second power supply 20. is charged (step S111).

Then, the control unit 3 determines whether or not the voltage of the second power supply 20 is equal to or higher than a predetermined voltage (step S112). When the control unit 3 determines that the voltage of the second power supply 20 is not equal to or higher than the predetermined voltage (step S112, No), the process proceeds to step S108.

In addition, when the control unit 3 determines that the voltage of the second power supply 20 is equal to or higher than the predetermined voltage (step S112, Yes), the battery switch 42 is turned off (step S113), and the automatic operation control device 100 automatically operates. A permission signal is output to permit automatic operation (step S114), and the process ends.

Here, the predetermined voltage in step S105 (here, referred to as first predetermined voltage) and the predetermined voltage in step S112 (here, referred to as second predetermined voltage) may have a hysteresis of about 1V.

For example, the first predetermined voltage is a voltage corresponding to SOC 80%, and the second predetermined voltage is a voltage corresponding to SOC 81%. As a result, frequent repetition of charging and stopping of charging of the second power supply 20 can be prevented, so deterioration of the LiB 21 can be suppressed.

In the example shown in FIG. 9, the case where the second power source 20 is charged while the vehicle is stopped has been described. may also be configured to charge the second power source 20 .

Further, in the example shown in FIG. 9, the predetermined process executed from when the control unit 3 is activated until the automatic operation is permitted has been described. repeats the process of However, in this case, if the control unit 3 determines in step S105 that the voltage of the second power supply 20 is equal to or lower than the predetermined voltage (step S105, Yes), the control unit 3 prohibits automatic operation, and then proceeds to step S106. Move.

Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the invention are not limited to the specific details and representative embodiments so shown and described. Accordingly, various changes may be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and equivalents thereof.

1 power supply control device 10 first power supply 11 DC/DC
12PbB
20 second power supply 21 LiB
3 control unit 41 inter-system switch 42 battery switch 51 first voltage sensor 52 second voltage sensor 100 automatic operation control device 101 first load 102 general load 103 second load 110 first system 120 second system

Claims (5)

a first system that supplies power from the first power supply to the first load;
a second system that supplies power from the second power supply to the second load;
an inter-system switch that connects the first system and the second system;
A control unit that turns on the inter-system switch during normal operation during automatic operation and non-automatic operation, and turns off the inter-system switch when a ground fault in the first system or the second system is detected,
The control unit
A power supply control device that turns off the inter-system switch when the voltage of the second power supply drops below a predetermined voltage during normal operation during non-automatic operation. A battery switch that connects the second power supply to the second system,
The control unit
2. The power supply control device according to claim 1, wherein when the voltage of the second power supply drops below a predetermined voltage during normal non-automatic operation, the inter-system switch and the battery switch are turned off. The control unit
3. The power supply control according to claim 2, wherein when the voltage of the second power supply is equal to or lower than the predetermined voltage, the inter-system switch and the battery switch are turned on while the vehicle is stopped to charge the second power supply. Device. The control unit
The power supply control device according to claim 3, wherein the battery switch is turned off when charging of the second power supply is completed. a first system that supplies power from the first power supply to the first load;
a second system that supplies power from the second power supply to the second load;
an inter-system switch that connects the first system and the second system;
A control unit of a power control device comprising
Turning on the inter-system switch during normal operation during automatic operation and non-automatic operation, and turning off the inter-system switch when a ground fault in the first system or the second system is detected,
A power supply control method, comprising turning off the inter-system switch when the voltage of the second power supply drops below a predetermined voltage in normal times during non-automatic operation.

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