Power supply system for electric powered vehicle, control method thereof, and electric powered vehicle

• US 8,773,065 B2
• Filed: 11/10/2010
• Issued: 07/08/2014
• Est. Priority Date: 11/10/2010
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ang, Wanleng
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): BOATENG, ALEXIS ASIEDUA
• Application Number:
  US13/881,064
• Publication Number:
  US 20130221921A1
• Time in Patent Office: 1,336 Days
• Field of Search: 320/104, 320/109, 320/137, 320/134, 320/136, 320/140, 320/166, 320/111, 320/135, 307/10.1
• US Class Current: 320/104
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 1/04 fed by the power supply line
• CPC Class Codes: B60L 15/007 Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles
• CPC Class Codes: B60L 2210/12 Buck converters
• CPC Class Codes: B60L 2210/14 Boost converters
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: B60L 53/20 characterised by converters located in the vehicle
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles

Abstract

A charger converting electric power from an external power supply into charging power for a power storage device converts AC power on a power line into charging power for an auxiliary battery. A CHR connects or disconnects a path between the charger and the power storage device. A DC/DC converter converts DC power on a power line connected to a smoothing capacitor into charging power for the auxiliary battery and outputs the power onto a power line. An ECU discharges the smoothing capacitor even if the voltage on the power line is lower than a determination voltage by causing the DC/DC converter to operate to charge the auxiliary battery in a discharging mode where the CHR is set OFF.

Claims

1. A power supply system for an electric powered vehicle, comprising:

a main power storage device for storing electric power input/output with respect to an electric motor generating vehicle driving power,

a charger configured including a smoothing capacitor, for converting electric power from an external power supply into charging power for said main power storage device,

a sub-power storage device having an output voltage lower than the output voltage of said main power storage device,

a power converter provided between said charger and said sub-power storage device, configured to convert the power on a first power line connected to said smoothing capacitor into charging power for said sub-power storage device, and

a control device for controlling an operation of said power converter based on a voltage on said first power line,

said control device, in an external charging mode by said charger, causing said power converter to operate to charge said sub-power storage device when the voltage on said first power line is higher than a first determination voltage, and stopping said power converter when the voltage on said first power line is lower than said first determination voltage, and in a discharging mode of said smoothing capacitor at an end of said external charging, causing said power converter to operate to convert stored charge in said smoothing capacitor into charging power for said sub-power storage device even when the voltage on said first power line becomes lower than said first determination voltage.

2. The power supply system for an electric powered vehicle according to claim 1, wherein said control device causes said power converter to operate such that an output voltage or output current to said sub-power storage device is constant when the voltage on said first power line is higher than said first determination voltage, and causes said power converter to operate such that said output current is maximum when said power converter is to be operated in an event of the voltage on said first power line being lower than said first determination voltage.

3. The power supply system for an electric powered vehicle according to claim 1, further comprising a second relay between said first power line and said sub-power storage device, connected bypassing said power converter,

wherein said control device sets said second relay ON when the voltage on said first power line is lower than a second determination voltage that is lower than said first determination voltage in said discharging mode.

4. The power supply system for an electric powered vehicle according to claim 1, further comprising a boost circuit for boosting the voltage on said first power line for output to an input side of said power converter,

wherein said control device provides control such that an input voltage of said power converter becomes higher than said first determination voltage by said boost circuit when said power converter is to be operated in an event of the voltage on said first power line being lower than said first determination voltage.

5. The power supply system for an electric powered vehicle according to claim 1, wherein

said smoothing capacitor includes

a first capacitor connected to said first power line, and

a second capacitor connected to a second power line different from said first power line,

said charger includes a power conversion unit for carrying out DC power conversion between said first power line and said second power line, and

said power conversion unit operates to convert power on said second power line for output to said first power line in said discharging mode.

6. The power supply system for an electric powered vehicle according to claim 1, wherein said first determination voltage is determined corresponding to a lower limit of a rated input voltage range of said power converter.

7. A method of controlling a power supply system for an electric power vehicle incorporating an electric motor that generates vehicle driving power,

said power supply system including

a main power storage device for storing electric power input/output with respect to said electric motor,

a charger configured including a smoothing capacitor, for converting electric power from an external power supply into charging power for said main power storage device,

a sub-power storage device having an output voltage lower than the output voltage of said main power storage device, and

a power converter provided between said charger and said sub-power storage device, configured to convert the power on a first power line connected to said smoothing capacitor into charging power for said sub-power storage device,

said method of controlling comprising the steps of:

comparing a voltage on said first power line with a first determination voltage when operation of said power converter is instructed,

causing said power converter to operate to charge said sub-power storage device when the voltage on said first power line is higher than the first determination voltage,

causing said power converter to operate to convert stored charge in said smoothing capacitor into charging power for said sub-power storage device in a discharging mode of said smoothing capacitor at an end of external charging, when the voltage on said first power line is lower than said first determination voltage, and

stopping said power converter in a mode other than said discharging mode when the voltage on said first power line is lower than said first determination voltage.

8. The method of controlling a power supply system for an electric powered vehicle according to claim 7, wherein

in said step of charging, said power converter is operated such that output voltage or output current to said sub-power storage device is constant, and

in said step of converting, said power converter is caused to operate such that said output current is maximum.

9. The method of controlling a power supply system for an electric powered vehicle according to claim 7, said power supply system further including a second relay between said first power line and said sub-power storage device, connected bypassing said power converter,

said method of controlling further comprising the step of setting said second relay ON when a voltage on said first power line is lower than a second determination voltage that is lower than said first determination voltage in said discharging mode.

10. The method of controlling a power supply system for an electric powered vehicle according to claim 7, said power supply system further including a boost circuit for boosting the voltage on said first power line for output to an input side of said power converter,

said method of controlling further comprising the step of controlling such that input voltage of said power converter becomes higher than said first determination voltage by said boost circuit when said power converter is to be operated in an event of the voltage on said first power line being lower than said first determination voltage.

11. An electric powered vehicle allowing charging by an external power supply, said electric powered vehicle comprising:

an electric motor generating vehicle driving power,

a main power storage device for storing electric power input/output with respect to said electric motor,

a charger configured including a smoothing capacitor, for converting electric power from said external power supply into charging power for said main power storage device,

a sub-power storage device having an output voltage lower than the output voltage of said main power storage device,

a power converter provided between said charger and said sub-power storage device, configured to convert the power on a first power line connected to said smoothing capacitor into charging power for said sub-power storage device, and

a control device for controlling an operation of said power converter based on a voltage on said first power line,

said control device, in an external charging mode by said charger, causing said power converter to operate to charge said sub-power storage device when the voltage on said first power line is higher than a first determination voltage, and stopping said power converter when the voltage on said first power line is lower than said first determination voltage, and in a discharging mode of said smoothing capacitor at an end of said external charging, causing said power converter to operate to convert stored charge in said smoothing capacitor into charging power for said sub-power storage device even when the voltage on said first power line becomes lower than said first determination voltage.

12. The electric powered vehicle according to claim 11, wherein said control device causes said power converter to operate such that an output voltage or output current to said sub-power storage device is constant when the voltage on said first power line is higher than said first determination voltage, and causes said power converter to operate such that said output current is maximum when said power converter is to be operated in an event of the voltage on said first power line being lower than said first determination voltage.

13. The electric powered vehicle according to claim 11, wherein

said smoothing capacitor includes

a first capacitor connected to said first power line, and

a second capacitor connected to a second power line different from said first power line,

said charger includes a power conversion unit for carrying out DC power conversion between said first power line and said second power line, and

said power conversion unit operates to convert power on said second power line for output to said first power line in said discharging mode.

14. The electric powered vehicle according to claim 11, further comprising a second relay between said first power line and said sub-power storage device, connected bypassing said power converter,

wherein said control device sets said second relay ON when the voltage on said first power line is lower than a second determination voltage that is lower than said first determination voltage in said discharging mode.

15. The electric powered vehicle according to claim 11, further comprising a boost circuit for boosting the voltage on said first power line for output to said power converter,

wherein said control device provides control such that an input voltage of said power converter becomes higher than said first determination voltage by said boost circuit when said power converter is to be operated in an event of the voltage on said first power line being lower than said first determination voltage.