Power output apparatus, motor vehicle equipped with power output apparatus, and control method of power output apparatus

• US 20060175995A1
• Filed: 01/13/2006
• Published: 08/10/2006
• Est. Priority Date: 01/13/2005
• Status: Active Grant

• Current Assignee: Aisin AW Company Limited (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Aisin AW Company Limited (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Shinmura, Osamu, Uechi, Tatsuyuki
• Granted Patent: US 7,245,094 B2
• Time in Patent Office: Days
• US Class Current: 318/139
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/44 Series-parallel type
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60L 2240/425 Temperature
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/50 Control strategies for responding to system failures, e.g. for fault diagnosis, failsafe operation or limp mode
• CPC Class Codes: B60W 2510/087 Temperature
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y10S 903/904 Component specially adapted for hev

Abstract

In the vehicle of the invention, when the temperature of an inverter 42 for driving a motor MG2 linked to front wheels 62a and 62b reaches or exceeds a preset restriction start temperature, the drive control of the invention controls the inverters 42 and 43 to gradually decrease the output torque of the motor MG2 simultaneously with a gradual increase in output torque of a motor MG3, which is linked to rear wheels 64a and 64b. Such torque control ensures output of a torque demand required for the vehicle. When the temperature of the inverter 42 reaches or exceeds a preset frequency switchover temperature, which is higher than the restriction start temperature, the drive control of the invention controls the inverters 42 and 43 to lower a switching frequency of transistors T1 to T6 in the inverter 42 and to ensure output of the torque demand. Such drive control effectively relieves the load of the inverter 42, while decreasing the frequency of lowering the switching frequency of the inverter 42. This arrangement thus desirably attains both prevention of overheat of the inverter 42 and reduces the switching noise.

Claims

1. A power output apparatus that outputs power for driving, said power output apparatus comprising:

multiple motors that are capable of outputting power for driving;

multiple driving circuits that individually have switching elements and respectively drive the multiple motors by switching operations of the switching elements;

a power demand setting module that sets a power demand in response to an operator'"'"'s operation; and

a control module that, when all the multiple driving circuits are in a normal state, drives and controls the multiple driving circuits to ensure output of a power equivalent to the set power demand from the multiple motors,

when one of the multiple driving circuits is in an abnormal state, said control module driving and controlling the multiple driving circuits to restrict output of the power from a motor driven by the driving circuit in the abnormal state, prior to restriction of a switching frequency of the switching elements included in the driving circuit in the abnormal state and to ensure output of the power equivalent to the set power demand from the multiple motors.

2. A power output apparatus in accordance with claim 1, wherein said control module drives and controls a driving circuit heated to at least a preset first temperature among the multiple driving circuits, as the driving circuit in the abnormal state.

3. A power output apparatus in accordance with claim 2, wherein when one of the multiple driving circuits is heated to the preset first temperature, said control module drives and controls the multiple driving circuits to restrict output of the power from a motor driven by the driving circuit heated to the preset first temperature and to ensure output of the power equivalent to the set power demand from the multiple motors,

when one of the multiple driving circuits is heated to a preset second temperature, which is higher than the preset first temperature, said control module driving and controlling the multiple driving circuits to restrict the switching frequency of the switching elements included in at least the driving circuit heated to the preset second temperature and to ensure output of the power equivalent to the set power demand from the multiple motors.

4. A power output apparatus in accordance with claim 1, wherein said control module drives and controls the multiple driving circuits to enable a motor driven by a driving circuit in the normal state to compensate for an insufficiency of the power caused by the restriction of the output of the power from the motor driven by the driving circuit in the abnormal state.

5. A power output apparatus in accordance with claim 4, wherein said control module drives and controls the multiple driving circuits to gradually decrease the power output from the motor driven by the driving circuit in the abnormal state, simultaneously with a gradual increase in power output from the motor driven by the driving circuit in the normal state.

6. A power output apparatus in accordance with claim 4, wherein when the motor driven by the driving circuit in the normal state fails to compensate for the insufficiency of the power caused by the restriction of output of the power from the motor driven by the driving circuit in the abnormal state in a preset power range, said control module drives and controls the multiple driving circuits to restrict the switching frequency of the switching elements included in at least the driving circuit in the abnormal state and to ensure output of the power equivalent to the set power demand from the multiple motors.

7. A power output apparatus in accordance with claim 1, said power output apparatus further comprising:

an internal combustion engine that outputs power for driving,

wherein when one of the multiple driving circuits is in the abnormal state under operation of the internal combustion engine, said control module drives and controls the multiple driving circuits to restrict the switching frequency of the switching elements included in at least the driving circuit in the abnormal state and to ensure output of the power equivalent to the set power demand from the multiple motors.

8. A motor vehicle, said motor vehicle comprising:

multiple motors including a first motor that is capable of outputting power to first wheels and a second motor that is capable of outputting power to second wheels, which are different from the first wheels;

multiple driving circuits including a first driving circuit and a second driving circuit that individually have switching elements and respectively drive the first motor and the second motor by switching operations of the switching elements;

a power demand setting module that sets a power demand in response to an operator'"'"'s operation; and

a control module that, when all the multiple driving circuits are in a normal state, drives and controls the multiple driving circuits to ensure output of a power equivalent to the set power demand from the multiple motors,

when the first driving circuit among the multiple driving circuits is in an abnormal state, said control module driving and controlling the multiple driving circuits to restrict output of the power from the first motor driven by the first driving circuit, prior to restriction of a switching frequency of the switching elements included in the first driving circuit and to enable the second motor to compensate for an insufficiency of the power caused by the restriction, thus ensuring output of the power equivalent to the set power demand from the multiple motors.

9. A control method of a power output apparatus, said power output apparatus comprising:

multiple motors that are capable of outputting power for driving; and

multiple driving circuits that individually have switching elements and respectively drive the multiple motors by switching operations of the switching elements,

said control method comprising the steps of;

(a) setting a power demand in response to an operator'"'"'s operation; and

(b) when all the multiple driving circuits are in a normal state, driving and controlling the multiple driving circuits to ensure output of a power equivalent to the set power demand from the multiple motors,

when one of the multiple driving circuits is in an abnormal state, driving and controlling the multiple driving circuits to restrict output of the power from a motor driven by the driving circuit in the abnormal state, prior to restriction of a switching frequency of the switching elements included in the driving circuit in the abnormal state and to ensure output of the power equivalent to the set power demand from the multiple motors.

10. A control method in accordance with claim 9, wherein said step (b) drives and controls a driving circuit heated to at least a preset first temperature among the multiple driving circuits, as the driving circuit in the abnormal state.

11. A control method in accordance with claim 10, wherein when one of the multiple driving circuits is heated to the preset first temperature, said step (b) drives and controls the multiple driving circuits to restrict output of the power from a motor driven by the driving circuit heated to the preset first temperature and to ensure output of the power equivalent to the set power demand from the multiple motors,

when one of the multiple driving circuits is heated to a preset second temperature, which is higher than the preset first temperature, said step (b) driving and controlling the multiple driving circuits to restrict the switching frequency of the switching elements included in at least the driving circuit heated to the preset second temperature and to ensure output of the power equivalent to the set power demand from the multiple motors.

12. A control method in accordance with claim 9, wherein said step (b) drives and controls the multiple driving circuits to enable a motor driven by a driving circuit in the normal state to compensate for an insufficiency of the power caused by the restriction of the output of the power from the motor driven by the driving circuit in the abnormal state.

13. A control method in accordance with claim 12, wherein said step (b) drives and controls the multiple driving circuits to gradually decrease the power output from the motor driven by the driving circuit in the abnormal state, simultaneously with a gradual increase in power output from the motor driven by the driving circuit in the normal state.

14. A control method in accordance with claim 12, wherein when the motor driven by the driving circuit in the normal state fails to compensate for the insufficiency of the power caused by the restriction of output of the power from the motor driven by the driving circuit in the abnormal state in a preset power range, said step (b) drives and controls the multiple driving circuits to restrict the switching frequency of the switching elements included in at least the driving circuit in the abnormal state and to ensure output of the power equivalent to the set power demand from the multiple motors.

15. A control method in accordance with claim 9, wherein said power output apparatus comprises an internal combustion engine that outputs power for driving;

and

when one of the multiple driving circuits is in the abnormal state under operation of the internal combustion engine, said step (b) drives and controls the multiple driving circuits to restrict the switching frequency of the switching elements included in at least the driving circuit in the abnormal state and to ensure output of the power equivalent to the set power demand from the multiple motors.