Electric powered vehicle and its control method

• US 8,103,396 B2
• Filed: 12/21/2007
• Issued: 01/24/2012
• Est. Priority Date: 01/25/2007
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Mitsutani, Noritake
• Primary Examiner(s): Black, Thomas
• Assistant Examiner(s): Huynh, Luke
• Application Number:
  US12/312,817
• Publication Number:
  US 20100030412A1
• Time in Patent Office: 1,495 Days
• Field of Search: 701/22, 318/139, 180/65.1
• US Class Current: 701/22
• CPC Class Codes: B60L 2270/36 of vehicles
• CPC Class Codes: B60L 3/003 relating to inverters
• CPC Class Codes: B60L 3/0069 relating to the isolation, e.g. ground fault or leak current
• CPC Class Codes: B60L 3/0092 with use of redundant elements for safety purposes
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60T 1/10 by utilising wheel movement for accumulating energy, e.g. driving air compressors
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: F16H 61/16 Inhibiting or initiating shift during unfavourable conditions, e.g. preventing forward reverse shift at high vehicle speed, preventing engine over speed unintentional control input F16H61/18
• CPC Class Codes: F16H 61/18 Preventing unintentional or unsafe shift , e.g. preventing manual shift from highest gear to reverse gear
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A shift position of an electric powered vehicle is selected by operating a shift lever and a P position switch. A power source position is selected by operating a power switch. When any of switching elements forming an inverter device is short-circuited, selection of the shift position and the power source position is controlled such that simultaneous selection of a power source position at which inverter control is turned off and a shift position at which a parking lock mechanism is inactivated can be avoided. Therefore, inverter control for reducing short-circuit current caused by back electromotive force derived from rotation of a motor generator after occurrence of short-circuit failure can reliably be executed.

Claims

1. An electric powered vehicle, comprising:

an AC electric motor generator having a rotor with a magnet attached, and configured to allow alternate transmission of rotating force to/from a wheel;

an inverter device having a plurality of power semiconductor switching elements, and configured to convert a DC voltage of a power source to a driving voltage for said AC electric motor generator;

a controller for controlling said inverter device;

a shift position selecting unit for selecting one of a plurality of shift positions including at least a parking position, in accordance with an operation by a driver;

a parking lock mechanism activated when said parking position is selected; and

a power source position selecting unit for selecting one of a plurality of power source positions determining a group of devices to be objects of power supply among devices mounted on the vehicle, in accordance with an operation by the driver;

wherein

said plurality of power source positions include a first power source position allowing control of said power semiconductor switching element by said controller and a second power source position not allowing said control;

said electric powered vehicle further comprising

an overlapped state avoiding unit for avoiding a state in which selection of said second power source position and selection of a shift position at which said parking lock mechanism is inactive are overlapped, when a short-circuit failure of any of said plurality of power semiconductor switching elements has been detected.

2. The electric powered vehicle according to claim 1, wherein

said plurality of power semiconductor switching elements are arranged as upper and lower arm elements of a plurality of phases forming said inverter device;

and

when said short-circuit failure has been detected and the vehicle is towed, said controller performs short-circuit current reducing control by turning on, in each phase at which said short-circuit failure has not occurred among said plurality of phases, an arm element of the same side as the short-circuited power semiconductor switching element, among said upper and lower arm elements.

3. The electric powered vehicle according to claim 2, further comprising

an instructing unit recognizing, when vehicle speed of said electric powered vehicle attains to a prescribed speed or higher when said first power source position is selected and a neutral position is selected as said shift position, that said vehicle is being towed, and instructing said controller to execute said short-circuit current reducing control.

4. The electric powered vehicle according to claim 1, wherein

said overlapped state avoiding unit includes

a warning unit urging selection of said parking position, when an operation is made to instruct transition from said first power source position to said second power source position while a shift position at which said parking lock mechanism is inactive is selected, and

a suspending unit for suspending, after said warning unit urged selection of said parking position until said parking position is actually selected, transition by said power source position selecting unit from said first power source position to said second power source position.

5. The electric powered vehicle according to claim 1, wherein

said overlapping state avoiding unit includes

an automatic selecting unit causing said shift position selecting unit to automatically select said parking position, when an operation instructing transition from said first power source position to said second power source position is made while a shift position at which said parking lock mechanism is inactive is being selected.

6. The electric powered vehicle according to claim 1, wherein

said overlapped state avoiding unit includes

an automatic selecting unit causing said power source position selecting unit to select said first power source position, when a shift position at which said parking lock mechanism is inactivated is selected while said second power source position is being selected.

7. The electric powered vehicle according to claim 1, wherein

said overlapped state avoiding unit includes

a warning unit for urging selection of said first power source position when an operation releasing said parking position is made while said second power source position is being selected, and

a suspending unit for suspending, after said warning unit urged selection of said first power source position until said first power source position is actually selected, releasing of said parking position by said shift position selecting unit.

8. A method of controlling an electric powered vehicle, wherein

said electric powered vehicle includes

an AC electric motor generator having a rotor with a magnet attached, and configured to allow alternate transmission of rotating force to/from a wheel,

an inverter device having a plurality of power semiconductor switching elements, and configured to convert a DC voltage of a power source to a driving voltage for said AC electric motor generator,

a controller for controlling said inverter device,

a shift position selecting unit for selecting one of a plurality of shift positions including at least a parking position, in accordance with an operation by a driver,

a parking lock mechanism activated when said parking position is selected, and

a power source position selecting unit for selecting one of a plurality of power source positions determining a group of devices to be objects of power supply among devices mounted on the vehicle, in accordance with an operation by the driver;

and wherein

said plurality of power source positions include a first power source position allowing control of said power semiconductor switching element by said controller and a second power source position not allowing said control;

said control method comprising the steps of;

determining whether or not a short-circuit failure of any of said plurality of power semiconductor switching elements has been detected; and

avoiding, when it is determined that said short-circuit failure has been detected, a state in which selection of said second power source position and selection of a shift position at which said parking lock mechanism is inactivated, are overlapped.

9. The method of controlling an electric powered vehicle according to claim 8, wherein

said plurality of power semiconductor switching elements are arranged as upper and lower arm elements of a plurality of phases forming said inverter device;

and

when said short-circuit failure has been detected and the vehicle is towed, said controller performs short-circuit current reducing control by turning on, in each phase at which said short-circuit failure has not occurred among said plurality of phases, an arm element of the same side as the short-circuited power semiconductor switching element, among said upper and lower arm elements.

10. The method of controlling an electric powered vehicle according to claim 9, further comprising the step of

recognizing, when vehicle speed of said electric powered vehicle attains to a prescribed speed or higher when said first power source position is selected and a neutral position is selected as said shift position, that said vehicle is being towed, and instructing said controller to execute said short-circuit current reducing control.

11. The method of controlling an electric powered vehicle according to claim 8, wherein

said step of avoiding includes the steps of

urging selection of said parking position, when an operation is made to instruct transition from said first power source position to said second power source position while a shift position at which said parking lock mechanism is inactive is selected, and

suspending, after selection of said parking position is urged at said step of urging until said parking position is actually selected, transition by said power source position selecting unit from said first power source position to said second power source position.

12. The method of controlling an electric powered vehicle according to claim 8, wherein

said step of avoiding includes the step of

causing said shift position selecting unit to automatically select said parking position, when an operation instructing transition from said first power source position to said second power source position is made while a shift position at which said parking lock mechanism is inactive is being selected.

13. The method of controlling an electric powered vehicle according to claim 8, wherein

said step of avoiding includes the step of

causing said power source position selecting unit to automatically select said first power source position when a shift position at which said parking lock mechanism is inactivated is selected while said second power source position is being selected.

14. The method of controlling an electric powered vehicle according to claim 8, wherein

said step of avoiding includes the steps of

urging selection of said first power source position when an operation releasing said parking position is made while said second power source position is being selected, and

suspending, after selection of said first power source position is urged at said step of urging until said first power source position is actually selected, releasing of said parking position by said shift position selecting unit.