US-12623619-B2 - Power supply system

Abstract

The power supply system includes a high-voltage battery connected to the drive device by a high-voltage system power line, a low-voltage battery connected to the auxiliary device by a low-voltage system power line, a main power converter connected to the high-voltage system power line and the low-voltage system power line, and a bidirectional charger connected to the external power side and the high-voltage system power line for charging the high-voltage battery and supplying the voltage of the high-voltage battery to an external electric load. When a failure is detected in the main power converter, the charger power converter is controlled so as to step down the power of the high-voltage system power line by the charger power converter and supply the power to the low-voltage system power line.

Inventors

• Daisuke Ueo

Assignees

• TOYOTA JIDOSHA KABUSHIKI KAISHA

Dates

Publication Date

20260512

Application Date

20241017

Priority Date

20240123

Claims (5)

1. 1 . A power supply system, comprising: a high-voltage battery connected to a drive device through a high-voltage system power line, the drive device being configured to drive a vehicle; a low-voltage battery connected to an auxiliary device mounted on the vehicle through a low-voltage system power line; a first power converter that is connected to the high-voltage system power line and the low-voltage system power line, and that is configured to convert a voltage between the high-voltage system power line and the low-voltage system power line bidirectionally; an inverter connected to an external power supply; a bidirectional charger that is connected to the high-voltage system power line and the inverter, and is configured to charge the high-voltage battery with external electric power from the external power supply or to supply voltage of the high-voltage battery to an external electric load; a control device configured to control the first power converter and the bidirectional charger; and a second power converter that is connected to the high-voltage system power line and the low-voltage system power line, and that is configured to step down and supply electric power from the high-voltage system power line to the low-voltage system power line, wherein the bidirectional charger includes the second power converter, and the control device is configured to determine whether a failure has occurred in the first power converter, and in a case where the failure has occurred in the first power converter, control the second power converter so as to step down the electric power of the high-voltage system power line and supply the stepped down electric power to the low-voltage system power line.
2. 2 . The power supply system according to claim 1 , further comprising: an equipotential line that connects an intermediate potential part of the high-voltage battery and the low-voltage system power line, the intermediate potential part having a potential equal to a reference potential of the low-voltage system power line; and a relay attached to the equipotential line, wherein the control device is configured to determine whether a failure in the low-voltage battery has occurred, in a case where the failure in the low-voltage battery has occurred, control the relay to be turned on so that electric power is supplied to the low-voltage system power line through the equipotential line.
3. 3 . The power supply system according to claim 2 , wherein the high-voltage battery is a lithium-ion secondary battery, and the low-voltage battery is a lead-acid battery.
4. 4 . The power supply system according to claim 2 , further comprising a system main relay disposed between the drive device and the high-voltage battery.
5. 5 . The power supply system according to claim 4 , wherein the system main relay is disposed between the high-voltage battery and a connection point where the first power converter connects to the high-voltage system power line.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to Japanese Patent Application No. 2024-008036 filed on Jan. 23, 2024, incorporated herein by reference in its entirety. BACKGROUND 1. Technical Field The present disclosure relates to power supply systems, and more particularly, to an in-vehicle power supply system including a high-voltage battery and a low-voltage battery. 2. Description of Related Art Conventionally, as a power supply system of this type, there has been proposed a power supply system including a high-voltage battery attached to a high-voltage system power line connected to an inverter that drives a motor for traveling, a low-voltage battery connected to an auxiliary device through a low-voltage system power line, and a bidirectional direct current (DC)/DC converter connected to the high-voltage system power line and the low-voltage system power line to step up and down and supply electric power (see, for example, Japanese Unexamined Patent Application Publication No. 2013-017357 (JP 2013-017357 A)). The system includes a charger connected to the high-voltage system power line to charge the high-voltage battery with external electric power, and an alternating current (AC)/DC converter connected to the low-voltage system power line to supply electric power to the outside. SUMMARY However, in the power supply system, when the bidirectional DC/DC converters fails, the low-voltage battery can drive the auxiliary device only until the voltage of the low-voltage battery reaches a voltage at which the auxiliary machine can be driven. Therefore, the vehicle can travel in a limp home mode for only a short distance. When the low-voltage battery fails, the bidirectional DC/DC converters can supply electric power to the low-voltage system power line, though the voltage of the low-voltage system power line may become unstable, and driving of the auxiliary device may become unstable. The power supply system of the present disclosure allows stable travel in a limp home mode over a relatively long distance even in the event of a failure. The power supply system of the present disclosure employs the following measure in order to achieve the main object. The power supply system of the present disclosure includes: a high-voltage battery connected to a drive device that drives a vehicle through a high-voltage system power line;a low-voltage battery connected to an auxiliary device mounted on the vehicle through a low-voltage system power line;a main power converter connected to the high-voltage system power line and the low-voltage system power line to step up and down and supply electric power;a bidirectional charger connected to the high-voltage system power line to charge the high-voltage battery with external electric power or to supply voltage of the high-voltage battery to an external electric load; anda control device that controls the main power converter and the bidirectional charger. In the power supply system, the bidirectional charger includes a charger power converter connected to an external power side and the high-voltage system power line to step up and down and supply electric power,the charger power converter is connected to the low-voltage system power line, andwhen detecting a failure in the main power converter, the control device controls the charger power converter so as to step down the electric power of the high-voltage system power line by the charger power converter and supply the stepped down electric power to the low-voltage system power line. The power supply system of the present disclosure includes a high-voltage battery connected to a drive device that drives a vehicle through a high-voltage system power line; a low-voltage battery connected to an auxiliary device mounted on the vehicle through a low-voltage system power line;a main power converter connected to the high-voltage system power line and the low-voltage system power line to step up and down and supply electric power;a bidirectional charger connected to the high-voltage system power line to charge the high-voltage battery with external electric power or to supply voltage of the high-voltage battery to an external electric load; anda control device that controls the main power converter and the bidirectional charger. The bidirectional charger includes a charger power converter connected to an external power side and the high-voltage system power line to step up and down and supply electric power, and the charger power converter is connected to the low-voltage system power line. When detecting a failure in the main power converter, the control device controls the charger power converter so as to step down the electric power of the high-voltage system power line by the charger power converter and supply the stepped down electric power to the low-voltage system power line. Accordingly, even when a failure occurs in the main power converter, the electric power of the high-voltage system power line