JP2023007922A - Power supply system - Google Patents

Abstract

To provide a power supply system having a plurality of power systems, the power supply system appropriately performing power supply to an electric load.SOLUTION: A power supply system 100 comprises: an inter-system switch SWA provided on a connection path LB; a first path LC1 and a second path LC2 that are provided in parallel with each other between a second power supply 16 and a connection point PB, in a second system E2, with the connection path LB; a first switch SWB provided on the first path LC1; and a voltage conversion circuit 26 and second switches SWC, SWD that are provided in series on the second path LC2. The power supply system 100 raises power supply voltage of first power supplies 10, 12, 14 using the voltage conversion circuit 26 in a state in which the inter-system switch SWA is closed, the first switch SWB is opened, and the second switches SWC, SWD are closed; charges a power storage device 16 to voltage higher than the power supply voltage; and, in a state of completion of the charging, makes the first switch SWB and the second switches SWC, SWD be in an open state.SELECTED DRAWING: Figure 1

Description

The present invention relates to power systems.

As a power supply system, a configuration has been proposed in which power is supplied by a plurality of power systems in order to provide redundancy in power supply to electrical loads. For example, a vehicle is equipped with an electric braking device, an electric steering device, and the like as electric loads that perform functions necessary for driving the vehicle. There is a concern that the continuation of vehicle driving will be hindered. Therefore, in order to prevent loss of function of each electric load even when an abnormality occurs during operation of a vehicle, there is known a device having a first power supply and a second power supply as power supplies for supplying electric power to the electric loads. there is

For example, in Patent Document 1, a first system having a first load and a second load as electrical loads for performing one function, a first system including a first power supply connected to the first load, and a second system connected to the second load A power supply system is disclosed having a second system including two power supplies. In this power supply system, an inter-system switch is provided in a connection path connecting each system, and the inter-system switch is opened when the controller determines that an abnormality has occurred in one of the systems. As a result, the electric load of the other system in which no abnormality has occurred ensures the functions necessary for driving the vehicle, and the driving of the vehicle can be continued.

JP 2019-62727 A

In the above power supply system, a configuration is conceivable in which a backup storage battery is provided as the second power supply of the second system. In this case, it is desired to reduce the capacity of the storage battery in order to reduce the cost, but it is considered that technical improvement is required to achieve this. For example, if a storage battery with a small capacity is used, the internal resistance of the storage battery will be greater than that of a storage battery with a large capacity. is concerned that it will become inappropriate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to properly supply power to an electric load in a power supply system having a plurality of power supply systems.

A first means for solving the above problems includes a first system that supplies power from a first power source to an electric load through a first energization path, and a second power source to the electric load through a second energization path. and an inter-system switch provided in a connection path connecting the first energization path and the second energization path, wherein the first power supply is a power supply voltage capable of driving the electric load, the second power supply including a power storage device that can be charged by the power supply voltage of the first power supply, and a connection point with the connection path in the second system A first path and a second path provided in parallel with each other between the second power supply, a first switch provided in the first path, a voltage conversion circuit provided in series in the second path, and In a state in which the second switch and the inter-system switch are closed, and the first switch is opened and the second switch is closed, the power supply voltage of the first power supply is boosted by the voltage conversion circuit, and the power storage is performed. a charging control unit that charges the device to a voltage higher than the power supply voltage; and a switch control unit that opens the first switch and the second switch when the charging by the charging control unit is completed. .

According to the above configuration, it is possible to supply electric power to the electrical load from two systems. For example, when an abnormality occurs in one of the systems, the system switch is opened to prevent the abnormality from occurring. It is possible to drive the electric load by supplying power from the system on the non-existing side. Further, in the second system having the second power supply, the first path and the second path are provided in parallel between the second power supply and the connection point of the connection path between the first current path and the second current path. , the first switch is provided on the first path, and the voltage conversion circuit and the second switch are provided in series on the second path. Then, with the inter-system switch closed, the first switch opened and the second switch closed, the power supply voltage of the first power supply is boosted by the voltage conversion circuit, and the power storage device reaches a voltage higher than the power supply voltage. to charge the battery. In addition, the first switch and the second switch are opened when the charging of the power storage device is completed.

In this case, the power storage device is charged with a voltage higher than the power supply voltage of the first power supply by the voltage conversion circuit, so that even if the power storage device has a relatively small capacity, the power storage device can be used as a backup power storage device. It can be used properly as a device. A second switch is provided in series with the voltage conversion circuit, and unnecessary discharge from the power storage device is restricted by opening the second switch. Therefore, even if a power storage device with a small capacity is used, desired electric power can be supplied. As described above, it is possible to appropriately supply electric power to electric loads in a power supply system having a plurality of power supply systems.

In the second means, the second switch includes a power supply side switch provided closer to the second power supply than the voltage conversion circuit and a counter power supply side switch provided closer to the connection point than the voltage conversion circuit. including.

According to the above configuration, by opening the switches on the power supply side and the anti-power supply side, the voltage conversion circuit can be disconnected from any power supply when an abnormality such as a ground fault occurs in the voltage conversion circuit. .

In the third means, the power-side switch and the anti-power-side switch are semiconductor switching elements having parasitic diodes, and the power-side switch is configured such that the forward direction of the parasitic diode is directed from the voltage conversion circuit to the power storage circuit. The anti-power-side switch is connected so that the forward direction of the parasitic diode thereof is in the direction from the voltage conversion circuit to the connection point.

According to the above configuration, since the power supply side switch and the anti-power supply side switch are configured by semiconductor switching elements, the cost can be reduced compared to the case where they are configured by relay switches. In addition, since the power supply side switch and the anti-power supply side switch are connected so that the forward directions of their parasitic diodes are opposite to each other, it is possible to suppress the dark current from flowing through the parasitic diodes. can. Further, the power-side switch is connected so that the forward direction of its parasitic diode is in the direction from the voltage conversion circuit to the power storage device, and the counter-power-side switch is connected so that the forward direction of its parasitic diode is the voltage conversion circuit. Therefore, even if the voltage conversion circuit is grounded, for example, unnecessary discharge and power supply via the parasitic diode can be regulated.

In the fourth means, when the first power supply of the first power supply and the second power supply is to supply power to the electrical load, the inter-system switch is closed and the first switch and the second power supply are switched. a power supply control unit that opens the inter-system switch and the second switch and closes the first switch when the second power supply is allowed to supply power to the electrical load while the second switch is opened; Prepare.

In the above configuration, the inter-system switch, the first switch, and the second switch are linked and opened and closed based on which one of the first power supply and the second power supply supplies power to the electric load. bottom. As a result, the power supply from the first power supply to the electric load and the power supply from the second power supply to the electric load can be properly carried out.

In the fifth means, the power supply control unit closes the first switch when the voltage of the power storage device drops below a predetermined threshold during power supply to the electrical load from the second power supply. The first state in which the second switch is opened is shifted to a second state in which the first switch is opened, the second switch is closed, and the voltage of the power storage device is boosted by the voltage conversion circuit.

In the above configuration, when the voltage of the power storage device drops below the threshold due to the power supply from the power storage device of the second power supply, the power storage device changes from the state (first state) in which power is directly supplied from the power storage device to the electric load. is boosted by the voltage conversion circuit to shift to a state (second state) in which power is supplied to the electric load. As a result, even when the voltage of the power storage device drops below the threshold value, it is possible to continue the proper power supply to the electrical load. Further, even if a power storage device with a small capacity is used, it is possible to extend the driving period of the electric load while using up the power of the power storage device.

In the sixth means, the power supply control unit, after opening the first switch, when shifting from the first state to the second state when power is supplied to the electric load by the second power supply, closing the second switch;

When it is determined that the voltage of the power storage device has dropped below the threshold value during power supply by the second power supply, the first switch is opened and the second switch is closed, and the voltage conversion circuit reduces the voltage of the power storage device. In this case, when the second switch is closed first and the first switch is opened later, the voltage on the connection point side of the voltage conversion circuit becomes higher than the voltage on the second power supply side. As a result, the operation of the voltage conversion circuit may become unstable. In this regard, in the above configuration, the second switch is closed after the first switch is opened, so the voltage conversion circuit can be operated normally.

A seventh means is a power supply system that supplies a dark current to the electric load in a system halt state, wherein in the system halt state, the first switch is closed and the second switch is opened, and the A dark current supply unit for supplying dark current from the power storage device is provided.

When the power storage device of the second power supply is charged with a voltage higher than the power supply voltage of the first power supply and the power supply system enters a stopped state, the power storage device is maintained in a high SOC state in the system stopped state. There is concern about deterioration of the power storage device. On the other hand, in the above configuration, when the system is stopped, dark current is supplied from the power storage device to the electrical load. be able to.

In the eighth means, in a system stop state, before the voltage of the power storage device drops to the power supply voltage of the first power supply, the dark current supply unit supplies the power to the power storage device with the inter-system switch open. After a dark current is supplied and the voltage of the power storage device becomes lower than the power supply voltage of the first power supply, the dark current is supplied by the power storage device with the inter-system switch closed, or The inter-system switch is closed, and the dark current supply by the power storage device is stopped while the first switch and the second switch are opened.

In the system stop state, before the voltage of the power storage device of the second power supply drops to the power supply voltage of the first power supply, the inter-system switch is opened to suppress the flow of DC current from the power storage device to the first power supply. In addition, it is possible to supply the electric load with dark current from the power storage device. The dark current supply by the power storage device causes the voltage of the power storage device to drop. If a power storage device with a small capacity is used, the voltage of the power storage device drops faster than the voltage of the first power supply, and the voltage of the power storage device drops to the power supply voltage of the first power supply. If the power storage device continues to supply the dark current while the inter-system switch is open, there is concern that the voltage of the power storage device may drop excessively. In this regard, after the voltage of the power storage device of the second power supply drops below the power supply voltage of the first power supply, the inter-system switch is closed, or the dark current is supplied by the power storage device when the inter-system switch is closed. is stopped, it is possible to suppress an excessive drop in the voltage of the power storage device while continuing to supply the dark current to the electrical load.

In the ninth means, in a system stop state, the voltage of the power storage device has a first voltage range between a first threshold lower than the power supply voltage of the first power supply and a second threshold lower than the first threshold. and a voltage determination unit that determines that the voltage of the power storage device has decreased to a second voltage range that is equal to or lower than the second threshold value; When it is determined that the voltage has dropped to the first voltage range, the power storage device is charged by the first power supply in a state in which the inter-system switch and the first switch are closed and the second switch is opened. and when the voltage determination unit determines that the voltage of the power storage device has decreased to the second voltage range, the inter-system switch and the second switch are closed, and the first switch is opened. and a stop control unit that charges the power storage device by the voltage conversion circuit.

In the system stop state, the power storage device of the second power supply may be over-discharged due to natural discharge or the like. In this case, in order to suppress deterioration of the power storage device due to overdischarge, it is conceivable to charge the power storage device by supplying power from the first power supply in the system stopped state. , there is concern that a rush current may flow into the power storage device when the power storage device is charged, and the power storage device may deteriorate. In this regard, in the above configuration, if the voltage of the power storage device has fallen to the first voltage range, the power storage device is charged by direct power supply from the first power supply, and the voltage of the power storage device reaches the second voltage range. If it is low, the power storage device is charged by power supply from the voltage conversion circuit. By using the voltage conversion circuit, the charging voltage can be increased stepwise when the power storage device is charged, and the power storage device can be charged while suppressing deterioration of the power storage device.

A tenth means is a power supply system mounted on a vehicle, wherein the electrical load is a load that performs at least one function necessary for driving in the vehicle, and a driving support function of the vehicle. The vehicle is capable of traveling in a first mode using the driving assistance function and traveling in a second mode not using the driving assistance function, and when the vehicle travels in the first mode, the The inter-system switch is closed to cause the first power source to supply power to the electric load, and the inter-system switch is closed when an abnormality occurs in the first system while the vehicle is running in the first mode. a control switching unit that opens and switches to power supply to the electric load by the second power supply; and a permitting unit that permits the vehicle to travel in the first mode on condition that charging by the charging control unit is completed. , provided.

In a power supply system applied to a vehicle having an electric load that is a function necessary for driving and that implements a driving support function, traveling in a first mode using the driving support function and a second mode not using the driving support function There are some that can be switched between running by Here, when the vehicle is running in the first mode (during driving support running), the inter-system switch is closed and power is supplied to the electric load by the first power supply. Further, when an abnormality occurs in the first system while the vehicle is traveling in the first mode, the inter-system switch is opened and the power supply to the electric load is switched to the second power supply. In such a configuration, the vehicle is permitted to travel in the first mode on condition that the power storage device of the second power supply is charged with a voltage higher than the power supply voltage of the first power supply. As a result, even if an abnormality occurs in the first system while the vehicle is running in the first mode, subsequent appropriate fail-safe processing can be performed.

1 is an overall configuration diagram of a power supply system according to a first embodiment; FIG. 4 is a flowchart showing the procedure of control processing according to the first embodiment; 4 is a time chart showing an example of control processing according to the first embodiment; The whole block diagram of the power supply system in the 1st modification of 1st Embodiment. The whole block diagram of the power supply system in the 2nd modification of 1st Embodiment. 8 is a flowchart showing the procedure of control processing according to the second embodiment; 6 is a time chart showing an example of control processing according to the second embodiment; 10 is a flowchart showing the procedure of discharge processing according to the third embodiment; 4 is a time chart showing an example of discharge processing; 10 is a flow chart showing a procedure of discharge processing in a modified example of the third embodiment; 4 is a flowchart showing the procedure of charging processing; 4 is a time chart showing an example of charging processing; 4 is a time chart showing an example of charging processing; The whole block diagram of the power supply system in other embodiment.

(First embodiment)
An embodiment in which a power supply system according to the present invention is embodied as a vehicle-mounted power supply system 100 will be described below with reference to the drawings.

As shown in FIG. 1 , the power supply system 100 is a system that supplies power to general loads 30 and specific loads 32 . The power supply system 100 includes a high voltage storage battery 11 as a first power supply 10, a first converter 12 consisting of a DCDC converter, and a first storage battery 13, and a second storage battery 16 as a second power supply. The high-voltage storage battery 11 has a higher rated voltage (for example, several hundred volts) than the first storage battery 13 and the second storage battery 16, and is, for example, a lithium ion storage battery. The first converter 12 is a voltage generator that converts the power supplied from the high voltage storage battery 11 into power of the power supply voltage VA and supplies the power to the general load 30 and the specific load 32 . In this embodiment, the power supply voltage VA is a voltage that enables driving the general load 30 and the specific load 32 . The first storage battery 13 is, for example, a lead storage battery. Also, the second storage battery 16 is a power storage device that is, for example, a lithium ion storage battery.

The general load 30 is an electrical load (hereinafter simply referred to as a load) that is not used for driving control in a vehicle as a moving body, such as an air conditioner, an audio device, and a power window.

On the other hand, the specific load 32 is a load that performs at least one function used for driving control of the vehicle. It is a travel control device 52 or the like that monitors the situation around the vehicle. In this embodiment, the specific load 32 corresponds to an "electric load".

The specific load 32 has a configuration in which redundancy is provided for each function, and by having the first load 34 and the second load 36, even if an abnormality occurs, all of the functions are not lost. It has become. Specifically, the electric power steering device 50 has a first steering motor 50A and a second steering motor 50B. The electric brake device 51 has a first brake device 51A and a second brake device 51B. The travel control device 52 has a camera 52A and a laser radar 52B. The first steering motor 50A, the first braking device 51A, and the camera 52A correspond to the first load 34, and the second steering motor 50B, the second braking device 51B, and the laser radar 52B correspond to the second load 36. .

The first load 34 and the second load 36 together implement one function, but each alone can implement a part of the function. For example, in the electric power steering device 50, the vehicle can be steered freely by the first steering motor 50A and the second steering motor 50B. , 50B enable steering of the vehicle.

Each specific load 32 realizes a function of assisting control by the driver in manual operation. In addition, each specific load 32 realizes a function necessary for automatic operation in automatic operation in which behavior such as running and stopping of the vehicle is automatically controlled. Therefore, the specific load 32 can also be said to be a load that performs at least one function required for driving the vehicle.

A general load 30 and a first load 34 are connected to the first power supply 10 via a first intra-system path LA1 as a first energization path. In this embodiment, the first power supply 10, the general load 30, and the first load 34 connected by the first intra-system path LA1 constitute the first system ES1.

Further, the second load 36 and the second storage battery 16 are connected to the second storage battery 16 via a second intra-system path LA2 as a second energization path. In this embodiment, the second system ES2 is configured by the second storage battery 16 and the second load 36 that are connected by the second intra-system path LA2.

The intra-system paths LA1 and LA2 are connected to each other by a connection path LB, and an inter-system switch SWA is provided on the connection path LB. One end of the connection path LB is connected to the connection point PA of the first intra-system path LA1, and the other end of the connection path LB is connected to the connection point PB of the second intra-system path LA2. In this embodiment, an N-channel MOSFET (hereinafter simply MOSFET) is used as the inter-system switch SWA.

A first path LC1 and a second path LC2 are provided in parallel between the connection point PB with the connection path LB in the second system ES2 and the second storage battery 16 . The first path LC1 is provided with an in-system switch SWB as a system main relay switch (SMR). In this embodiment, a MOSFET is used as the in-system switch SWB. In this embodiment, the in-system switch SWB corresponds to the "first switch".

A second converter 26, a battery side switch SWC, and a load side switch SWD are provided in series on the second path LC2. In this embodiment, the second converter 26 is a one-way power conversion circuit having a boost charge function that boosts the power supply voltage VA to charge the second storage battery 16 . In this embodiment, the second converter 26 corresponds to the "voltage conversion circuit".

The battery side switch SWC is provided closer to the second storage battery 16 than the second converter 26 on the second path LC2. The load side switch SWD is provided closer to the connection point PB than the second converter 26 on the second path LC2. In this embodiment, the battery side switch SWC and the load side switch SWD correspond to the "second switch". Also, the battery side switch SWC corresponds to the "power supply side switch", and the load side switch SWD corresponds to the "opposite power supply side switch".

The connection path LB is provided with a first voltage detection section 28 that detects the voltage at the connection point PA. Further, the second intra-system path LA2 is provided with a second voltage detection unit 29 that detects the voltage at the connection point PB.

The control device 40 has a well-known microcomputer consisting of a CPU, ROM, RAM, flash memory, and the like. The CPU refers to the arithmetic programs and control data in the ROM, and implements various functions for manual operation and automatic operation. Specifically, the control device 40 controls the open/closed states of the switches SWA to SWD. Control device 40 also switches converters 12 and 26 between an operating state and an operating stop state.

The control device 40 uses the specific load 32 described above to manually and automatically drive the vehicle. Note that manual operation refers to a state in which the vehicle is controlled by the driver's operation. Further, automatic driving represents a state in which the operation of the vehicle is controlled by the content of control by the control device 40 regardless of the driver's operation. Specifically, automated driving refers to automated driving at level 3 or higher among automated driving levels from level 0 to level 5 defined by the U.S. Department of Transportation Highway Traffic Safety Administration (NHTSA). Level 3 is a level at which the control device 40 controls both steering operation and acceleration/deceleration while observing the running environment.

In addition, the control device 40 can implement driving support functions such as LKA (Lane Keeping Assist), LCA (Lane Change Assist), and PCS (Pre-Crash Safety) using the specific load 32 described above. The control device 40 can switch the driving mode of the vehicle between a first mode using the driving support function and a second mode not using the driving support function, and the vehicle can run in each driving mode. . The control device 40 switches between the first mode and the second mode according to a switching instruction from the driver via the input unit 46 . Here, the first mode includes a mode in which the driver manually drives the vehicle using the driving support function, and a mode in which the vehicle is automatically driven. The second mode is a mode in which the driver manually drives the vehicle without using the driving assistance function.

In the first mode, the control device 40 determines whether or not an abnormality has occurred in the first system ES1 and the second system ES2. When it is determined that neither system ES1 nor ES2 has an abnormality, Automatic driving and driving assistance of the vehicle are performed using the first load 34 and the second load 36 . Thereby, the first and second loads 34, 36 cooperate to perform one function necessary for automatic driving and driving assistance. In this embodiment, anomalies include ground faults, power faults, overvoltages, disconnections, and the like.

On the other hand, when it is determined that an abnormality has occurred in either one of the systems ES1 and ES2, the inter-system switch SWA is opened to electrically isolate the first system ES1 and the second system ES2. As a result, even if an abnormality occurs in one of the systems ES1, ES2, the loads 34, 36 of the other system ES1, ES2 in which no abnormality has occurred can be driven.

The control device 40 is also connected to the notification section 44, the IG switch 45, and the input section 46 and controls them. The notification unit 44 is a device that notifies the driver visually or audibly, and is, for example, a display or speaker installed in the vehicle compartment. The IG switch 45 is a vehicle activation switch. Controller 40 monitors whether IG switch 45 is open or closed. The input unit 46 is a device that receives a driver's operation, such as a steering wheel operation input device, a shift lever operation input device, an accelerator pedal operation input device, a brake pedal operation input device, and a voice input device.

In the power supply system 100, it is conceivable to use the second storage battery 16 as a backup storage battery. Here, the backup storage battery means an emergency storage battery that supplies power to the second load 36 when, for example, the inter-system switch SWA is opened due to the occurrence of an abnormality in the first system ES1. In this case, it is required to reduce the capacity of the second storage battery 16 in order to reduce costs. However, when a storage battery with a small capacity is used, the internal resistance is increased compared to a storage battery with a large capacity, and the degree of reduction in battery capacity is increased. Therefore, the voltage VB of the second storage battery 16 is likely to decrease when the power supply from the second storage battery 16 is started, and there is concern that the operation of the second load 36 may become inappropriate.

In this embodiment, the inter-system switch SWA is closed, the intra-system switch SWB is opened, and the battery side switch SWC and the load side switch SWD are closed. A control process is performed to charge the second storage battery 16 to a voltage higher than the power supply voltage VA. In the control process, the in-system switch SWB, the battery-side switch SWC, and the load-side switch SWD are opened when charging of the second storage battery 16 is completed.

In this case, since the second storage battery 16 is charged with a voltage higher than the power supply voltage VA by the second converter 26, even if the second storage battery 16 is a storage battery with a relatively small capacity, the second storage battery 16 can be used. It can be appropriately used as a backup storage battery. In addition, a battery side switch SWC and a load side switch SWD are provided in series with the second converter 26, and unnecessary discharge from the second storage battery 16 is regulated. Desired electric power can be supplied even if the

FIG. 2 shows a flowchart of the control processing of this embodiment. When the IG switch 45 is closed, the control device 40 repeats the control process at predetermined control cycles. Note that the running mode of the vehicle is set to the second mode when the IG switch 45 is initially closed.

When the control process is started, first, in step S10, it is determined whether or not the running mode of the vehicle is the first mode. If a negative determination is made in step S10, it is determined in step S11 whether or not the voltage VB of the second storage battery 16 is higher than a predetermined high voltage threshold value VH. Here, the high voltage threshold VH is set to a voltage higher than the power supply voltage VA by a predetermined value or more. For example, the power supply voltage VA is 12 [V] and the high voltage threshold VH is 15 [V]. If the voltage VB of the second storage battery 16 is lower than the high voltage threshold VH, the preconditions for implementing the first mode are not met, so a negative determination is made in step S11, and the process proceeds to step S12. In this embodiment, the process of step S10 corresponds to the "control switching unit", and the process of step S11 corresponds to the "permitting unit".

In step S12, it is determined whether or not an abnormality has occurred in at least one of the second converter 26 and the switches SWB to SWD of the second system ES2. A control circuit included in the second converter 26 is used to determine whether or not an abnormality has occurred in the second converter 26 and at least one of the switches SWB to SWD. If an abnormality has occurred in at least one of the second converter 26 and the switches SWB to SWD, the preconditions for charging the second storage battery 16 are not satisfied, so a negative determination is made in step S12, and the process proceeds to step S13. . In step S13, the inter-system switch SWA is closed, the switches SWB to SWD are opened, the first converter 12 is activated, the second converter 26 is deactivated, and the control process ends. That is, the electric power supplied from the first converter 12 is used to drive the loads 34 and 36 .

When the second converter 26 and all of the switches SWB to SWD are normal, the second storage battery 16 is charged, so an affirmative determination is made in step S12, and the process proceeds to step S14. In step S14, the intersystem switch SWA, the battery side switch SWC, and the load side switch SWD are closed, the in-system switch SWB is opened, the first and second converters 12 and 26 are put into the operating state, and the control process ends. In other words, the power supplied from the first converter 12 is used to drive the loads 34 and 36, and the power supplied from the first converter 12 is used to increase the voltage higher than the power supply voltage VA to the second voltage. The storage battery 16 is charged. In addition, in this embodiment, the process of step S14 corresponds to a "charge control part."

If the voltage VB of the second storage battery 16 is higher than the high voltage threshold VH, charging of the second storage battery 16 by the second converter 26 is completed, so an affirmative determination is made in step S11, and the process proceeds to step S15. In step S15, the system switch SWA is closed, the switches SWB to SWD are opened, the first converter 12 is activated, and the second converter 26 is deactivated. That is, the first converter 12 is caused to supply power to the loads 34 and 36 . In the subsequent step S16, switching of the driving mode of the vehicle from the second mode to the first mode is permitted, and the control process ends. Switching to the first mode is performed, for example, when a switching instruction such as an instruction to use the driving support function or an automatic driving instruction is input from the driver via the input unit 46 . In this embodiment, the process of step S15 corresponds to the "switch control section", and the process of step S16 corresponds to the "mode control section".

On the other hand, if an affirmative determination is made in step S10, it is determined in steps S20 to S22 whether or not an abnormality has occurred in any one of the first system ES1, the second system ES2, and the second converter . Specifically, in step S20, it is determined whether or not an abnormality has occurred in the first system ES1. If a negative determination is made in step S20, it is determined in step S21 whether or not an abnormality has occurred in the second system ES2. If a negative determination is made in step S21, it is determined whether or not an abnormality has occurred in the second converter 26 in step S22.

The occurrence of abnormality in the first system ES1 is determined by whether or not the voltage detected by the first voltage detection unit 28 has decreased below a predetermined low voltage threshold VL. Here, the low voltage threshold VL is set to a voltage higher than the operating lower limit voltages of the loads 34 and 36 by a predetermined value or more. Occurrence of abnormality in the second system ES2 is determined by whether or not the voltage detected by the second voltage detection unit 29 has decreased below the low voltage threshold VL.

Further, the occurrence of an abnormality in second converter 26 is determined using a control circuit included in second converter 26 . For example, in a state where the battery side switch SWC and the load side switch SWD are open, the ground fault of the second converter 26 is determined by detecting the current in the second converter 26 by the control circuit included in the second converter 26. be done. In the first mode, the battery-side switch SWC and the load-side switch SWD are open. Therefore, in the present embodiment, the occurrence of abnormality in the second converter 26 is detected separately from the occurrence of abnormality in the second system ES2.

If it is determined that no abnormality has occurred in any of them, a negative determination is made in step S22. In this case, the control process ends. As a result, the switches SWB to SWD are kept open, and discharge of the second storage battery 16 is restricted. As a result, unnecessary discharge from the second storage battery 16 is restricted.

On the other hand, when it is determined that an abnormality has occurred in either one of the systems ES1 and ES2, power supply to the system in which the abnormality has occurred is stopped, and power is supplied to the electric load of the system in which the abnormality has not occurred. process to continue.

Specifically, when an affirmative determination is made in step S20, the inter-system switch SWA is first opened in step S23. In subsequent step S24, the in-system switch SWB is closed, and the discharge regulation of the second storage battery 16 is released. As a result, power supply from the second storage battery 16 to the second load 36 is ensured via the first path LC1. It is preferable that the period from the opening of the inter-system switch SWA to the closing of the intra-system switch SWB be within 1 ms, preferably within 100 μs.

In the subsequent step S25, a command to stop the operation of the first converter 12 is output, and the process proceeds to step S27. In addition, in this embodiment, the processing of steps S23 and S24 corresponds to the "power supply control unit".

If an affirmative determination is made in step S21, the inter-system switch SWA is opened in step S26, and the process proceeds to step S27. As a result, the power supply from the first converter 12 to the first load 34 is continued, and the power supply from the first converter 12 to the second load 36 is interrupted. Moreover, when affirmative determination is made in step S22, the process proceeds to step S27.

In step S27, the driver is notified of the occurrence of the abnormality via the notification unit 44, and the control process ends. In the present embodiment, when an abnormality occurs in any one of the first system ES1, the second system ES2, and the second converter 26, the control device 40 switches the running mode of the vehicle from the first mode to the second mode. , a process of moving the vehicle to a safe place in the first mode and then stopping the vehicle.

Next, FIG. 3 shows an example of control processing. FIG. 3 shows the voltage VB of the second storage battery 16 and the voltage VB applied to the second load 36 when a ground fault (hereinafter simply ground fault) occurs in the first system ES1 while the vehicle is running in the first mode. shows the transition with the load voltage VD.

In FIG. 3, (A) shows the transition of the state of the IG switch 45, (B) shows the transition of the running mode of the vehicle, and (C) shows the transition of the occurrence of the ground fault in the first system ES1. show. (D) shows the transition of the open/closed state of the inter-system switch SWA, (E) shows the transition of the open/closed state of the intra-system switch SWB, and (F) shows the battery-side switch SWC and the load-side switch SWD. (G) shows the transition of the operating state of the second converter 26 . Furthermore, (H) indicates transition of the voltage VB of the second storage battery 16 and (I) indicates transition of the load voltage VD of the second load 36 .

As shown in FIG. 3, during the open period of the IG switch 45 up to time t1, that is, in the resting state of the power supply system 100, the switches SWA to SWD are open, and the first and second converters 12 and 26 are in an operation stop state. is switched to Therefore, the load voltage VD becomes zero during the open period of the IG switch 45 .

When the IG switch 45 is closed at time t1, the inter-system switch SWA is closed and a command to switch the first converter 12 to the operating state is output. As a result, the first converter 12 is switched to the operating state, the power supply voltage VA and the load voltage VD are increased to the operating voltage VM as a predetermined threshold value, and the vehicle can run in the second mode. Here, the operating voltage VM is a voltage within the driving voltage range of the loads 34 and 36 .

At time t1, the battery side switch SWC and the load side switch SWD are closed, and a command to switch the second converter 26 to the operating state is output. As a result, the voltage VB of the second storage battery 16 increases. At time t2, when the voltage VB of the second storage battery 16 becomes higher than the high voltage threshold VH, the running mode of the vehicle is switched from the second mode to the first mode, and the battery side switch SWC and the load side switch SWD are opened. At the same time, a command to switch the second converter 26 to the non-operating state is output.

It is determined that a ground fault has occurred in either the first system ES1 or the second system ES2 while the vehicle is running in the first mode. If it is determined that the ground fault has not occurred in any of the systems ES1 and ES2, the inter-system switch SWA is kept closed. As a result, power can be supplied from the first converter 12 and the first storage battery 14 to the first and second loads 34 and 36, respectively. The power supply from the first converter 12 enables continuous power supply even during long hours of automatic operation, and the power supply from the first storage battery 14 enables power supply with less voltage fluctuation. As a result, during the period from time t2 to time t3, automatic driving and driving assistance using the first load 34 and the second load 36 are performed.

When it is determined that a ground fault has occurred in either one of the systems ES1, ES2, the inter-system switch SWA is closed. In FIG. 3, a ground fault occurs in the first system ES1 at time t3. This reduces the load voltage VD. At time t4, when the load voltage VD drops to the low voltage threshold VL, it is determined that a ground fault has occurred in the first system ES1. In this case, at time t4, the inter-system switch SWA is opened and the first converter 12 is switched to the operation stop state.

At time t4, the in-system switch SWB is closed. As a result, power is supplied from the second storage battery 16 to the second load 36 via the first path LC1, and the load voltage VD increases. In the present embodiment, when an abnormality occurs in the first system ES1, the voltage VB of the second storage battery 16 rises to the high voltage threshold VH that is higher than the operating voltage VM of the power supply voltage VA. It rises to near the high voltage threshold VH. Therefore, a predetermined voltage difference ΔV can be secured between the load voltage VD and the low voltage threshold VL. As a result, even if a storage battery with a small capacity is used as the second storage battery 16, the second load 36 can be properly operated.

According to this embodiment detailed above, the following effects can be obtained.

According to this embodiment, the second storage battery 16 is charged with a voltage higher than the power supply voltage VA by the second converter 26 . Therefore, even if the second storage battery 16 is a storage battery with a relatively small capacity, the second storage battery 16 can be appropriately used as a backup storage battery. In addition, a battery side switch SWC and a load side switch SWD are provided in series with the second converter 26 to restrict unnecessary discharge from the second storage battery 16 . Therefore, even if a storage battery with a small capacity is used, desired electric power can be supplied. As described above, power supply to loads 34 and 36 can be appropriately performed in power supply system 100 having a plurality of systems ES1 and ES2.

According to this embodiment, the battery side switch SWC is provided on the second storage battery 16 side of the second converter 26 . Therefore, even if the second converter 26 is grounded, for example, by opening the battery side switch SWC, the second converter 26 can be disconnected from the second storage battery 16, and unnecessary discharge from the second storage battery 16 is restricted. can do. A load side switch SWD is provided on the connection point PB side of the second converter 26 . Therefore, even if the second converter 26 is grounded, for example, by opening the load side switch SWD, the first converter 12 can be disconnected from the second storage battery 16, and unnecessary power supply from the first converter 12 can be stopped. can be regulated.

According to this embodiment, the switches SWB to SWD are linked and opened and closed based on which one of the first converter 12 and the second storage battery 16 supplies power to the loads 34 and 36 . As a result, the power supply from the first converter 12 to the loads 34 and 36 and the power supply from the second storage battery 16 to the loads 34 and 36 can be performed properly.

In this embodiment, when the vehicle travels in the first mode, the inter-system switch SWA is closed and power is supplied to the loads 34 and 36 by the first converter 12 . Further, when a ground fault occurs in the first system ES1 while the vehicle is running in the first mode, the inter-system switch SWA is opened to switch to power supply to the second load 36 by the second storage battery 16 . In this embodiment, the vehicle is allowed to travel in the first mode on condition that the second storage battery 16 is charged with a voltage higher than the power supply voltage VA. As a result, even if an abnormality should occur in the first system ES1 while the vehicle is running in the first mode, subsequent appropriate fail-safe processing can be performed.

(First Modification of First Embodiment)
As shown in FIG. 4, in this modification, MOSFETs, which are semiconductor switching elements, are used as the battery side switch SWC and the load side switch SWD. Therefore, a parasitic diode DPB is connected in parallel to the battery side switch SWC, and a parasitic diode DPD is connected in parallel to the load side switch SWD. In this embodiment, the battery side switch SWC and the load side switch SWD are connected such that the forward directions of the parasitic diodes DPC and DPD are opposite to each other. Specifically, the battery-side switch SWC is connected such that the forward direction of the parasitic diode DPC is the direction from the second converter 26 to the second storage battery 16 . The load side switch SWD is connected such that the forward direction of the parasitic diode DPD is the direction from the second converter 26 to the connection point PB.

According to the modification described in detail above, the battery side switch SWC and the load side switch SWD are configured by MOSFETs, so that the cost of the power supply system 100 can be reduced compared to the case where they are configured by relay switches. . Also, the battery side switch SWC and the load side switch SWD are connected so that the forward directions of their parasitic diodes DPC and DPD are opposite to each other. Therefore, it is possible to suppress dark current from flowing through the parasitic diodes DPC and DPD. Further, the battery side switch SWC is connected so that the forward direction of its parasitic diode DPC is the direction from the second converter 26 to the second storage battery 16, and the load side switch SWD is connected so that the forward direction of its parasitic diode DPD is connected. The connection is made so that the direction is the direction from the second converter 26 to the connection point PB. Therefore, even if the voltage conversion circuit is grounded, for example, unnecessary discharge and power supply through the parasitic diodes DPC and DPD can be restricted.

(Second Modification of First Embodiment)
As shown in FIG. 5, a fuse HZ may be provided between the battery side switch SWC and the second converter 26 .

(Second embodiment)
The second embodiment will be described below with reference to FIGS. 6 and 7, focusing on differences from the first embodiment.

In this embodiment, the second converter 26 has a step-up charging function of stepping up the power supply voltage VA to charge the second storage battery 16, and stepping up the voltage VB of the second storage battery 16 and outputting it to the second load 36. It is a bi-directional power conversion circuit having a step-up discharge function. Then, in the first mode, when it is determined that an abnormality has occurred in the first system ES1, the voltage VB of the second storage battery 16 is reduced by using the second converter 26 as the voltage VB of the second storage battery 16 decreases. is stepped up and output to the second load 36, which is different from the first embodiment.

That is, when an abnormality occurs in the first system ES1, the control device 40 moves the vehicle to a safe place and then stops the vehicle. There is no safe place in the road and you want to extend the period before stopping the vehicle. In particular, if a storage battery with a small capacity is used as the second storage battery 16, the period until the vehicle is stopped is relatively short, so it is desired to extend the period. In the present embodiment, when the voltage VB of the second storage battery 16 drops due to the power supply from the second storage battery 16, the state (first state) in which power is directly supplied from the second storage battery 16 to the second load 36 is changed. , the voltage VB of the second storage battery 16 is stepped up by the second converter 26 to shift to a state (second state) in which electric power is supplied to the second load 36 . As a result, even when the voltage VB of the second storage battery 16 drops, the proper power supply to the second load 36 can be continued.

FIG. 6 shows a flowchart of the control processing of this embodiment. In FIG. 6, for the sake of convenience, the same step numbers are assigned to the same processes as those shown in FIG. 2, and the description thereof is omitted.

In the control process of the present embodiment, if an affirmative determination is made in step S20, it is determined in step S30 whether or not the voltage VB of the second storage battery 16 has decreased to the operating voltage VM of the power supply voltage VA. If a negative determination is made in step S30, the process proceeds to step S23.

On the other hand, if an affirmative determination is made in step S30, first, in step S31, the in-system switch SWB is opened. In the subsequent step S32, the battery side switch SWC and the load side switch SWD are closed. In the present embodiment, the battery side switch SWC and the load side switch SWD are closed after the in-system switch SWB is opened.

In the subsequent step S33, a command to set the second converter 26 to the operating state is output, and the process proceeds to step S27. In step S33, a command is output to cause the second converter 26 to perform the boost discharge function. Thereby, the second converter 26 starts boosting the voltage VB of the second storage battery 16 .

Next, FIG. 7 shows an example of control processing. Note that (A) to (I) of FIG. 7 are the same as (A) to (I) of FIG. 3, and thus description thereof is omitted. In addition, in FIG. 7, the processing up to time t4 is the same as the processing shown in FIG. 3, so the description is omitted.

As shown in FIG. 7, when the in-system switch SWB is closed at time t4, the voltage VB of the second storage battery 16 and the load voltage VD decrease due to the power supply to the second load 36 from the second storage battery 16. . At time t5, when the voltage VB of the second storage battery 16 drops to the operating voltage VM of the power supply voltage VA, the in-system switch SWB is opened and the battery side switch SWC and the load side switch SWD are closed.

Further, at time t5, a command is output to cause the second converter 26 to perform the boost discharge function. As a result, the voltage VB of the second storage battery 16 is stepped up and output to the second load 36 . In this embodiment, as a result of the second converter 26 increasing the voltage VB of the second storage battery 16, the load voltage VD is maintained at the operating voltage VM of the power supply voltage VA.

At time t6, when the voltage VB of the second storage battery 16 drops to the predetermined lower limit voltage Vmin, the second converter 26 cannot boost the voltage VB of the second storage battery 16 to the operating voltage VM of the power supply voltage VA. , the battery-side switch SWC and the load-side switch SWD are opened, and a command to switch the second converter 26 to an operation stop state is output. As a result, the load voltage VD becomes zero. Also, at time t6, the running mode of the vehicle is switched from the first mode to the second mode, and the IG switch 45 is opened.

According to the control process of the present embodiment, the load voltage VD is maintained at the operating voltage VM of the power supply voltage VA until time t6, and the period during which the vehicle can be stopped is extended to time t6. Therefore, even if the vehicle cannot be stopped by time t5, the control device 40 can stop the vehicle after moving the vehicle to a safe place.

According to this embodiment detailed above, the following effects can be obtained.

According to the present embodiment, when the voltage VB of the second storage battery 16 drops below the operating voltage VM of the power supply voltage VA due to the power supply from the second storage battery 16, the second load 36 is directly charged from the second storage battery 16. From the state of supplying power (first state), the voltage VB of the second storage battery 16 is boosted by the second converter 26 to shift to the state of supplying power to the second load 36 (second state). As a result, even when the voltage VB of the second storage battery 16 drops below the operating voltage VM of the power supply voltage VA, proper power supply to the second load 36 can be continued. In addition, the driving period of the second load 36 can be extended while using up the capacity of the second storage battery 16 .

When it is determined that the voltage VB of the second storage battery 16 is lower than the operating voltage VM of the power supply voltage VA during power supply by the second storage battery 16, the system switch SWB is opened, the battery side switch SWC and the load side switch are opened. SWD is closed, and the voltage VB of the second storage battery 16 is boosted by the second converter 26. In this case, the battery side switch SWC and the load side switch SWD are closed first, When the in-system switch SWB is later opened, the voltage on the connection point PB side of the second converter 26 becomes higher than the voltage on the second storage battery 16 side, and the operation of the second converter 26 may become unstable. In this regard, in the present embodiment, the battery side switch SWC and the load side switch SWD are closed after the in-system switch SWB is opened, so that the second converter 26 can be operated normally.

(Third Embodiment)
The third embodiment will be described below with reference to FIGS. 8 and 9, focusing on differences from the first embodiment.

The present embodiment differs from the first embodiment in that the discharge process is performed while the IG switch 45 is open, that is, while the power supply system 100 is stopped. Dark current (standby current) is supplied to the loads 34 and 36 when the IG switch 45 is open, that is, when the power supply system 100 is stopped. is used to provide dark current to the loads 34,36.

That is, when the power supply system 100 is stopped while the second storage battery 16 is charged with a voltage higher than the power supply voltage VA, the second storage battery 16 is maintained in the high SOC state in the system stop state. There is concern about deterioration of the second storage battery 16 . In this embodiment, when the power supply system 100 is stopped, dark current is supplied to the loads 34 and 36 by the second storage battery 16, so deterioration of the second storage battery 16 can be suppressed.

FIG. 8 shows a flow chart of the discharge process of this embodiment. With the IG switch 45 open, the control device 40 repeatedly performs the discharge process at predetermined control cycles. The control device 40 can operate in a system stop state by supplying power even when the IG switch 45 is open.

When the discharging process is started, first, in step S40, it is determined whether or not the voltage VB of the second storage battery 16 is higher than the voltage VP of the first storage battery 14 . Here, the voltage VP of the first storage battery 14 is set to a voltage higher than the operating voltage VM of the power supply voltage VA. If an affirmative determination is made in step S40, in step S41, the system switch SWA is opened, the system switch SWB is closed, the battery side switch SWC and the load side switch SWD are opened, and the first and second converters 12 are stopped. As a state, the discharge process is terminated. It should be noted that in the present embodiment, the process of step S41 corresponds to the "dark current supply unit".

On the other hand, if a negative determination is made in step S40, the inter-system switch SWA is closed in step S42, and the discharge process ends.

Next, FIG. 9 shows an example of discharge processing. FIG. 9 shows changes in the voltage VB of the second storage battery 16 during the discharging process.

In FIG. 9, (A) shows transition of the state of the IG switch 45, (B) shows transition of the open/close state of the inter-system switch SWA, and (C) shows transition of the open/close state of the intra-system switch SWB. indicates Also, (D) shows transitions in the open/close state of the battery side switch SWC and the load side switch SWD, and (E) shows transitions in the voltage VB of the second storage battery 16 .

When the IG switch 45 is opened at time t11, the in-system switch SWB is closed. That is, the in-system switch SWB is closed and the battery side switch SWC and the load side switch SWD are opened. As a result, dark current is supplied by the second storage battery 16 via the in-system switch SWB.

In the example shown in FIG. 9, the voltage VB of the second storage battery 16 is higher than the voltage VP of the first storage battery 14 at time t11. Therefore, at time t11, the inter-system switch SWA is opened. As a result, dark current is supplied from the first storage battery 14 to the first load 34 in the first system ES1, and dark current is supplied from the second storage battery 16 to the second load 36 in the second system ES2. .

In this embodiment, since the capacity of the second storage battery 16 is smaller than the capacity of the first storage battery 14, the voltage VB of the second storage battery 16 drops to the voltage VP of the first storage battery 14 at time t12. In this case, the inter-system switch SWA is closed at time t12. As a result, dark current is supplied from the first and second storage batteries 14 and 16 to the loads 34 and 36 . Since the capacity of the first storage battery 14 is larger than the capacity of the second storage battery 16, the dark current supply to the loads 34 and 36 is mainly performed from the first storage battery 14, and the capacity and voltage of the second storage battery 16 are reduced. Suppressed.

After that, when the IG switch 45 is closed at time t13, the control device 40 is activated and control processing is performed.

According to this embodiment detailed above, the following effects can be obtained.

According to this embodiment, when the power supply system 100 is stopped, the loads 34 and 36 are supplied with the dark current by the second storage battery 16 . As a result, the SOC of the second storage battery 16 can be lowered while the electric power stored in the second storage battery 16 is effectively used, and deterioration of the second storage battery 16 can be suppressed.

In the system stop state, before the voltage VB of the second storage battery 16 drops to the voltage VP of the first storage battery 14, the system-to-system switch SWA is closed so that direct current flows from the second storage battery 16 to the first storage battery 14. The dark current can be supplied from the second storage battery 16 to the second load 36 while suppressing the flow of dark current. Since the dark current is supplied by the second storage battery 16, the voltage VB of the second storage battery 16 decreases. If the second storage battery 16 with a small capacity is used, the voltage VB of the second storage battery 16 drops faster than the voltage VP of the first storage battery 14, and the voltage VB of the second storage battery 16 drops below that of the first storage battery 14. However, in this case, if the second storage battery 16 continues to supply the dark current with the system switch SWA open, there is concern that the voltage VB of the second storage battery 16 may drop excessively. be done. In this respect, after the voltage VB of the second storage battery 16 drops below the voltage VP of the first storage battery 14, the inter-system switch SWA is closed so that the first and second storage batteries 14, 16 connected in parallel A dark current is supplied to the loads 34 , 36 . As a result, it is possible to prevent the voltage VB of the second storage battery 16 from excessively decreasing while continuing to supply the dark current to the loads 34 and 36 .

(Modified example of the third embodiment)
As shown in FIG. 10, in the present modification, when a negative determination is made in step S40 in the discharge process, the inter-system switch SWA is closed in step S42. In the subsequent step S43, the intra-system switch SWB is opened, and the discharging process ends. That is, when the voltage VB of the second storage battery 16 drops to the voltage VP of the first storage battery 14, the system switch SWB, the battery-side switch SWC, and the load-side switch SWD are opened, and the supply of the dark current by the second storage battery 16 is stopped. be done.

According to this modified example described in detail above, after the voltage VB of the second storage battery 16 drops below the voltage VP of the first storage battery 14, the inter-system switch SWA is closed and the dark current is supplied by the second storage battery 16. is stopped, dark current is supplied from the first storage battery 14 to the loads 34 and 36 . As a result, it is possible to prevent the voltage VB of the second storage battery 16 from excessively decreasing while continuing to supply the dark current to the loads 34 and 36 .

(Fourth embodiment)
The fourth embodiment will be described below with reference to FIGS. 11 to 13, focusing on differences from the first embodiment.

This embodiment differs from the first embodiment in that the charging process is performed while the power supply system 100 is stopped.

That is, if the vehicle is left for a long period of time while the power supply system 100 is stopped, the second storage battery 16 may be in an over-discharged state due to natural discharge or the like. In this case, in order to suppress deterioration of the second storage battery 16 due to overdischarging, it is conceivable to charge the second storage battery 16 by supplying power from the first converter 12 while the power supply system 100 is stopped. Depending on the extent of the overdischarge state of the storage battery 16, there is concern that an inrush current may flow through the second storage battery 16 when charging the second storage battery 16, causing the second storage battery 16 to deteriorate. In this embodiment, the battery side switch SWC and the load side switch SWD are closed according to the voltage VB of the second storage battery 16 so that the second storage battery 16 is charged by the second converter 26 . Thereby, the second storage battery 16 can be charged while suppressing deterioration of the second storage battery 16 due to the rush current.

FIG. 11 shows a flowchart of the charging process of this embodiment. With the IG switch 45 opened, the control device 40 repeatedly performs the charging process at each predetermined control cycle. Note that the control cycle of the charging process is set to be longer than the control cycle of the discharging process.

When the charging process is started, first, in step S50, it is determined whether or not the voltage VB of the second storage battery 16 is higher than the operating voltage VM of the power supply voltage VA. If an affirmative determination is made in step S50, the switches SWA to SWD are opened in step S51, the operation of the first and second converters 12 is stopped, and the charging process ends. Note that in the present embodiment, the operating voltage VM of the power supply voltage VA corresponds to the "first threshold".

If a negative determination is made in step S50, it is determined in step S52 whether or not the voltage VB of the second storage battery 16 is higher than the low voltage threshold VL. If an affirmative determination is made in step S52, the process proceeds to step S53, and if a negative determination is made in step S52, the process proceeds to step S56. It should be noted that in the present embodiment, the processing of steps S50 and S52 corresponds to the "voltage determination section", and the low voltage threshold VL corresponds to the "second threshold".

In step S53, a command is output to set the first converter 12 to an operating state. In the subsequent step S54, the inter-system switch SWA is closed. In the subsequent step S55, the intra-system switch SWB is closed to end the charging process.

In step S56, a command is output to set the first converter 12 to an operating state. In the subsequent step S57, the inter-system switch SWA is closed. In the subsequent step S58, the battery side switch SWC and the load side switch SWD are closed. In the subsequent step S59, a command is output to set the second converter 26 to the operating state, and the charging process is terminated. In this embodiment, the processing of steps S53 to S59 corresponds to the "stop control unit".

12 and 13 show an example of the charging process. 12 and 13 show changes in the voltage VB of the second storage battery 16 during discharge processing when the second storage battery 16 is used. In this embodiment, it is assumed that the second storage battery 16 shown in FIG. 13 is deteriorated compared to the second storage battery 16 shown in FIG.

12 and 13, (A) shows the transition of the state of the IG switch 45, (B) shows the transition of the voltage VB of the second storage battery 16, and (C) shows the transition of the charging process. indicates (D) shows the transition of the open/closed state of the inter-system switch SWA, (E) shows the transition of the open/closed state of the intra-system switch SWB, and (F) shows the battery-side switch SWC and the load-side switch SWD. shows the transition of the open/closed state of

When the IG switch 45 is opened at time t21, the system switch SWA is closed. That is, the inter-system switch SWA and the intra-system switch SWB are closed, and the battery side switch SWC and the load side switch SWD are opened. In the stopped state of the power supply system 100 with the IG switch 45 opened, the voltage VB of the second storage battery 16 gradually decreases due to natural discharge or the like. Also, in the stopped state of the power supply system 100, the charging process is performed at each predetermined control cycle.

In the examples shown in FIGS. 12 and 13, the charging process is performed at times t22 and t23. At time t22, the voltage VB of the second storage battery 16 is higher than the operating voltage VM of the power supply voltage VA. That is, since the second storage battery 16 is not in an over-discharged state, the second storage battery 16 is not charged.

On the other hand, at time t23, the voltage VB of the second storage battery 16 is lower than the voltage VP of the first storage battery 14, and the second storage battery 16 is charged. In this case, in the example shown in FIG. 12, the voltage VB of the second storage battery 16 is higher than the low voltage threshold VL because the second storage battery 16 has not deteriorated so much. That is, the voltage VB of the second storage battery 16 has decreased to the first voltage range HV1 between the operating voltage VM of the power supply voltage VA and the low voltage threshold VL. Therefore, at time t23, the inter-system switch SWA is closed, the intra-system switch SWB is closed, and the second storage battery 16 is charged via the first path LC1. When the second storage battery 16 is charged and the voltage VB of the second storage battery 16 rises to the operating voltage VM of the power supply voltage VA at time t24, the charging of the second storage battery 16 is terminated.

On the other hand, in the example shown in FIG. 13, since the second storage battery 16 is relatively deteriorated, the voltage VB of the second storage battery 16 is lower than the low voltage threshold VL. That is, the voltage VB of the second storage battery 16 has decreased to the second voltage range HV2, which is equal to or lower than the low voltage threshold VL. Therefore, at time t<b>23 , the system switch SWA is closed, the battery side switch SWC and the load side switch SWD are closed, and the second storage battery 16 is charged by the second converter 26 . When the voltage VB of the second storage battery 16 rises to the operating voltage VM of the power supply voltage VA at time t25 due to the charging of the second storage battery 16, the charging of the second storage battery 16 is terminated.

After that, when the IG switch 45 is closed at time t26, the control device 40 is activated and control processing is performed.

According to this embodiment detailed above, the following effects can be obtained.

According to the present embodiment, if the voltage VB of the second storage battery 16 has decreased to the first voltage range HV1, the second storage battery 16 is charged by direct power supply from the first converter 12, and the second storage battery 16 is charged. 16 is lowered to the second voltage range HV2, the second storage battery 16 is charged by power supply from the second converter 26. FIG. By using the second converter 26, the charging voltage can be increased stepwise when charging the second storage battery 16, and the second storage battery 16 can be charged while suppressing deterioration of the second storage battery 16 due to rush current. can do.

(Other embodiments)
The present invention is not limited to the description of the above embodiments, and may be implemented as follows.

Each load 34, 36 may be, for example, the following devices.

It may be a driving motor for applying driving power to the vehicle and its drive circuit. In this case, each of the first and second loads 34, 36 is, for example, a three-phase permanent magnet synchronous motor and a three-phase inverter device.

It may be an anti-lock brake device that prevents the wheels from locking during braking. In this case, each of the first and second loads 34, 36 is, for example, an ABS actuator that can independently adjust brake hydraulic pressure during braking.

Detects a vehicle traveling in front of the vehicle ahead, maintains a constant distance from the vehicle in front when the vehicle in front is detected, and maintains a constant distance between the vehicle and the vehicle in front when the vehicle in front is no longer detected. may be a cruise control device that drives at a preset vehicle speed. In this case, each of the first and second loads 34, 36 is, for example, a millimeter wave radar.

- Each load 34, 36 does not necessarily have to be a combination of the same configuration, and may be a combination of different types of devices that perform equivalent functions. Also, the first and second loads 34 and 36 may be the same load instead of different loads. That is, the first and second loads 34 and 36 may be the same load that receives power supply from both the first intra-system path LA1 and the second intra-system path LA2.

- The voltage generator of the first power supply is not limited to a converter, and may be an alternator. Also, the first power supply may not have the voltage generator, and may have only the first storage battery 14, for example.

- Although the example in which the second switch is composed of the battery side switch SWC and the load side switch SWD has been shown in the above embodiment, the present invention is not limited to this. It may be composed of only one of the battery side switch SWC and the load side switch SWD. Also, one of the battery side switch SWC and the load side switch SWD may be configured by a fuse.

- In the above-described embodiment, an example in which the first switch is configured by the in-system switch SWB is shown, but the present invention is not limited to this. It may be composed of two MOSFETs connected in series. In this case, by connecting these MOSFETs so that the forward directions of the parasitic diodes of these MOSFETs are opposite to each other, it is possible to suppress the dark current from flowing through the parasitic diodes.

Alternatively, as shown in FIG. 14, it may be composed of an in-system switch SWB composed of a MOSFET and first to third diodes DA1 to DA3 connected in series. A parasitic diode DPB is connected in parallel to the in-system switch SWB. The parasitic diode DPB is connected so that the direction from the connection point PB to the second storage battery 16 is the forward direction. The first to third diodes DA1 to DA3 are arranged closer to the connection point PB than the in-system switch SWB, and are connected in series with the in-system switch SWB. The first to third diodes DA1 to DA3 are connected so that the direction from the intra-system switch SWB to the connection point PB is the forward direction. Therefore, the parasitic diode DPB and the first to third diodes DA1 to DA3 are connected so that their forward directions are opposite to each other. Thereby, it is possible to suppress the dark current from flowing through the parasitic diode DPB.

- In the above-described embodiment, an example of determining the occurrence of an abnormality in the first system ES1 based on the voltage detected by the first voltage detection unit 28 is shown, but the present invention is not limited to this. A current detection unit is provided in a portion of the connection path LB closer to the first system ES1 than the inter-system switch SWA. can be determined, the first voltage detector 28 and the current detector may be used together.

In the above-described first embodiment, when it is determined that an abnormality has occurred in the first system ES1, an example is shown in which the inter-system switch SWA is opened and then the intra-system switch SWB is closed, but the intra-system switch SWB is closed. After that, the inter-system switch SWA may be opened. By closing the in-system switch SWB first, it is possible to prevent a momentary power failure of the second load 36 .

In the above-described second embodiment, the intra-system switch SWB is closed after the inter-system switch SWA is opened. Although the mode of delaying the timing of outputting the command to output is shown, the present invention is not limited to this. For example, by setting the timing at which the controller 40 outputs a command to open the inter-system switch SWA and the timing at which it outputs a command to close the intra-system switch SWB to be the same, the inter-system switch is switched by delaying command transmission by an element such as a capacitor. After opening SWA, the in-system switch SWB may be closed.

- In the above embodiment, the power supply system 100 is applied to a vehicle capable of driving manually and automatically, but the present invention is not limited to this. It may be applied to a vehicle that can only travel by automatic operation, such as a fully automated vehicle, or it may be applied to a vehicle that can only travel by manual operation.

- In the above-described embodiment, an example in which the power storage device is a lithium ion storage battery was shown, but the present invention is not limited to this. The storage element may be, for example, another type of storage battery or an electric double layer capacitor.

DESCRIPTION OF SYMBOLS 10... 1st power supply, 16... 2nd storage battery, 26... 2nd converter, 100... Power supply system, ES1... 1st system, ES2... 2nd system, LA1... Path in 1st system, LA2... Path in 2nd system , LB... connection path, LC1... first path, LC2... second path, PB... connection point, SWA... inter-system switch, SWB... intra-system switch, SWC... battery side switch, SWD... load side switch.

Claims (10)

a first system (ES1) that supplies electric power from the first power source (10) to the electric loads (34, 36) through the first current path (LA1);
a second system (ES2) that supplies power from a second power source (16) to the electrical load via a second current path (LA2);
A power supply system (100) comprising an inter-system switch (SWA) provided in a connection path (LB) connecting the first energization path and the second energization path,
The first power supply outputs a power supply voltage that enables driving of the electrical load,
The second power supply includes a power storage device (16) that can be charged with the power supply voltage of the first power supply,
a first path (LC1) and a second path (LC2) provided in parallel between a connection point (PB) with the connection path in the second system and the second power supply;
a first switch (SWB) provided on the first path;
a voltage conversion circuit (26) and second switches (SWC, SWD) provided in series in the second path;
With the inter-system switch closed, the first switch open, and the second switch closed, the power supply voltage of the first power supply is boosted by the voltage conversion circuit, and the power storage device is converted to the power supply voltage. a charging controller (40) for charging to a higher voltage than
a switch control unit (40) that opens the first switch and the second switch when charging by the charge control unit is completed;
Power system with The second switch includes a power supply side switch (SWC) provided closer to the second power supply than the voltage conversion circuit, and a counter power supply side switch (SWD) provided closer to the connection point than the voltage conversion circuit. 2. The power system of claim 1, comprising: the power-side switch and the anti-power-side switch are semiconductor switching elements having parasitic diodes;
the power supply side switch is connected such that the forward direction of the parasitic diode is in the direction from the voltage conversion circuit to the power storage device,
3. The power supply system according to claim 2, wherein said anti-power-side switch is connected such that the forward direction of said parasitic diode is in the direction from said voltage conversion circuit to said connection point. closing the inter-system switch and opening the first switch and the second switch when the first power supply out of the first power supply and the second power supply supplies power to the electrical load; and a power supply control unit (40) that opens the inter-system switch and the second switch and closes the first switch when the second power supply is caused to supply power to the electrical load. 4. The power supply system according to any one of 1 to 3. The power supply control unit closes the first switch and closes the second switch when the voltage of the power storage device drops below a predetermined threshold when power is supplied to the electrical load from the second power supply. 5. The power storage device according to claim 4, wherein said first switch is opened, said second switch is closed, and said first switch is opened, said second switch is closed, and the voltage of said power storage device is shifted to a second state in which said voltage conversion circuit boosts the voltage of said power storage device. power system. The power supply control unit closes the second switch after opening the first switch when shifting from the first state to the second state when power is supplied to the electric load by the second power supply. 6. The power system of claim 5, wherein: A power supply system that supplies a dark current to the electrical load in a system stop state,
7. The system according to any one of claims 1 to 6, further comprising a dark current supply unit (40) that closes the first switch and opens the second switch in the system stop state, and causes the power storage device to supply the dark current. A power system as described above. The dark current supply unit
In a system stop state, before the voltage of the power storage device drops to the power supply voltage of the first power supply, dark current is supplied by the power storage device with the inter-system switch opened, and the voltage of the power storage device is reduced. After the voltage drops below the power supply voltage of the first power supply, the power storage device is caused to supply a dark current with the inter-system switch closed, or the inter-system switch is closed, and the first switch and the 8. The power supply system according to claim 7, wherein supply of dark current by said power storage device is stopped while said second switch is open. In the system stop state, the voltage of the power storage device has decreased to a first voltage range between a first threshold lower than the power supply voltage of the first power supply and a second threshold lower than the first threshold; a voltage determination unit (40) that determines that the voltage of the power storage device has decreased to a second voltage range equal to or lower than the second threshold;
In a system stop state, when the voltage determination unit determines that the voltage of the power storage device has decreased to the first voltage range, the inter-system switch and the first switch are closed, and the second switch is opened. In this state, the power storage device is charged by the first power supply, and when the voltage determination unit determines that the voltage of the power storage device has decreased to the second voltage range, the inter-system switch and the second a stop time control unit (40) for charging the power storage device with the voltage conversion circuit in a state where the switch is closed and the first switch is opened;
The power system according to any one of claims 1 to 8, comprising: A power supply system mounted on a vehicle,
the electrical load is a load that performs at least one function necessary for driving in the vehicle and a load that performs a driving support function of the vehicle;
The vehicle is capable of running in a first mode using the driving assistance function and running in a second mode not using the driving assistance function,
When the vehicle is running in the first mode, the inter-system switch is closed to allow the first power supply to supply power to the electrical load, and when the vehicle is running in the first mode, the first system malfunctions. a control switching unit (40) that opens the inter-system switch and switches to power supply to the electrical load by the second power supply when
a permitting unit (40) for permitting switching of the traveling mode of the vehicle from the second mode to the vehicle traveling in the first mode on condition that charging by the charging control unit is completed;
The power system according to any one of claims 1 to 9, comprising:

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