Electric motor driving system, electric four-wheel drive vehicle, and hybrid vehicle

• US 7,317,295 B2
• Filed: 11/30/2006
• Issued: 01/08/2008
• Est. Priority Date: 03/31/2005
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kaneka, Satoru, Miyazaki, Hideki, Izumi, Shiho, Yamamoto, Tatsuyuki, Katsuhama, Kenta, Motegi, Kazuya
• Primary Examiner(s): Leykin; Rita
• Application Number:
  US11/565,074
• Publication Number:
  US 20070096683A1
• Time in Patent Office: 404 Days
• Field of Search: 318/800, 318/801, 318/802, 318/803, 318/139, 180/65.1, 180/65.3, 180/65.8, 701/1, 701/22, 320/136, 320/132
• US Class Current: 318/801
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/34 characterised by the absence of energy storing means
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60L 15/025 using field orientation; Vector control; Direct Torque Control [DTC]
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 2210/20 AC to AC converters
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/642 Slope of road
• CPC Class Codes: B60L 2260/28 Four wheel or all wheel drive
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/119 including control of all-wheel-driveline means, e.g. transfer gears or clutches for dividing torque between front and rear axle B60W10/14 takes precedence
• 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 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/081 : Speed
• CPC Class Codes: B60W 2552/15 : Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 30/18109 : Braking
• CPC Class Codes: B60W 30/18127 : Regenerative braking
• CPC Class Codes: H02P 27/04 : using variable-frequency supply voltage, e.g. inverter or converter supply voltage
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• 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 90/16 : Information or communication technologies improving the operation of electric vehicles

Abstract

An electric four-wheel drive vehicle includes: an internal combustion engine; a generator for outputting DC electrical power; an inverter for converting DC electrical power, output from the generator, into AC electrical power; and an AC electric motor, which is driven by the inverter, for driving rear wheels. An electric motor controller controls the inverter, the AC electric motor, and the generator, according to torque instructions from a vehicle. Furthermore, in a case that the output of the AC electric motor becomes negative, and excess electrical energy is generated, the electric motor controller controls the current applied to said AC electric motor such that the loss in said AC electric motor exceeds the negative output of said AC electric motor. This enables the AC electric motor to absorb excess electrical energy in the form of thermal loss.

Claims

1. A control system for an electric driving system for a vehicle, comprising:

an inverter for converting a DC electrical power output from a storage device capable of electrical charge and discharge of electric power into AC electrical power;

and an AC electric motor, driven by the AC electrical power output from said inverter for generating electrical driving force for driving a component to be driven,

wherein said control system for an electric driving system controls driving of said AC electric motor by controlling said inverter according to an instructed torque for said AC electric motor, and

wherein, with said storage device at or near a state of full, the electrical power output of said AC electric motor becomes negative, excess electrical energy is generated, and said control system controls the current applied to said AC electric motor such that the loss in said AC electric motor exceeds the negative electrical power output of said AC electric motor.

2. A control system for an electric driving system according to claim 1, wherein in a case that the electrical power output of said AC electric motor becomes negative, and excess electrical energy is generated, said control system controls the current applied to said AC electric motor so as to increase ineffective current in said AC electric motor.

3. A control system for an electric driving system according to claim 2, wherein the ineffective current in said AC electric motor, which is absorbed in the form of loss in said AC electric motor, is determined based upon the excess electrical power output to said inverter from said in-vehicle power supply.

4. A control system for an electric driving system for a vehicle, said electric driving system for a vehicle comprising:

an inverter for converting a DC electrical power output from a storage device capable of electrical charge and discharge of electric power into AC electrical power; and

an AC electric motor driven by the AC electrical power output from said inverter for driving at least one of said plurality of wheels other than said wheels driven by said internal combustion engine,

wherein said control system for an electric driving system controls driving of said AC electric motor by controlling said inverter according to an instructed torque received from a vehicle for said AC electric motor, and

wherein, with said storage device not at or near a state of full charge, a split-second large current by which the electrical power output of said AC electric motor becomes negative is generated, said storage device cannot accept all electric energy, the electrical power output of said AC electric motor becomes negative, and excess electrical energy is generated, said control system controlling the current applied to said AC electric motor such that the loss in said AC electric motor exceeds the negative electrical power output of said AC electric motor.

5. A control system for an electric driving system according to claim 4, wherein, with the output of said AC electric motor becoming negative, and excess electrical energy being generated, said control system controls the current applied to said AC electric motor so as to increase ineffective current in said AC electric motor.

6. A control system for an electric driving system according to claim 5, wherein the ineffective current in said AC electric motor, which is absorbed in the form of loss in said AC electric motor, is determined based upon the excess electrical power output to said inverter from said generator.

7. A control system for an electric driving system which drives a vehicle by electro-moving force comprising:

an inverter for converting a DC electrical power output from a storage device in which electrical charge and discharge of electric power is possible, into AC electrical power;

and an AC electric motor, which is driven by the AC electrical power output from said inverter, for generating electrical driving force for driving said vehicle,

wherein said control system for an electric driving system includes controlling driving of said AC electric motor by controlling said inverter according to an instructed torque received from a vehicle for said AC electric motor, and

wherein, with said storage device at or near a state of full charge, the electrical power output of said AC electric motor becoming negative, and excess electrical energy generated, said controls system controls the current applied to said AC electric motor such that the loss in said AC electric motor exceeds the negative electrical power output of said AC electric motor.

8. A control system for an electric driving system according to claim 7, wherein, with the electrical power output of said AC electric motor becoming negative and excess electrical energy being generated, said control system controls the current applied to said AC electric motor so as to increase ineffective current in said AC electric motor.

9. A control system for an electric driving system according to claim 8, wherein the ineffective current in said AC electric motor, which is absorbed in the form of loss in said AC electric motor, is determined based upon the excess electrical power output to said inverter from said storage device.

10. A control system for an electric driving system for a vehicle, comprising:

an inverter for converting a DC electrical power output from a storage device capable of electrical charge and discharge of electric power into AC electrical power;

an AC electric motor driven by the AC electrical power output from said inverter, for generating electrical driving force; and

a control unit for controlling driving of said AC electric motor by controlling said inverter according to an instructed torque for said AC electric motor,

wherein, with said storage device not at or near a state of full charge, a split-second large current which the electrical power output of said AC electric motor becomes negative is generated, said capacitor cannot finish accepting all electric energy, the electrical power output of said AC electric motor becomes negative, and excess electrical energy is generated, said control unit being configured to control the current applied to said AC electric motor such that the loss in said AC electric motor exceeds the negative electrical power output of said AC electric motor, and

wherein the excess electrical power is supplied to said inverter from an in-vehicle power supply in the form of loss in said AC electric motor.

11. An electric driving system for an electric driving system according to claim 10, wherein, with the electrical power output of said AC electric motor becoming negative, excess electrical energy is generated, and said control unit controls the current applied to said AC electric motor so as to increase ineffective current in said AC electric motor.

12. An electric driving system for an electric driving system according to claim 11, wherein the ineffective current in said AC electric motor is determined based upon the excess electrical power.

13. A hybrid vehicle comprising:

an internal combustion engine for generating driving force for a vehicle;

an AC electric motor for generating driving force for said vehicle;

a storage device forming a power supply for said AC electric motor;

an inverter for converting DC electrical power received from said storage device, into AC electrical power, which is supplied to said AC electric motor for driving said AC electric motor; and

a control device for controlling driving of said AC electric motor by controlling said inverter according to an instructed torque received from a vehicle for said AC electric motor,

wherein, with said storage device at nor near a state of full charge and the electrical power output of said AC electric motor becoming negative, excess electrical energy is generated, and said control device controls the current applied to said AC electric motor such that the loss in said AC electric motor exceeds the negative electrical power output of said AC electric motor, and

wherein the excess electrical power is supplied to said inverter from said storage device in the form of loss in said AC electric motor.

14. A hybrid vehicle comprising:

an internal combustion engine for generating driving force for a vehicle;

an AC electric motor for generating driving force for said vehicle;

a storage device forming a power supply for said AC electric motor;

an inverter for converting DC electrical power received from said storage device, into AC electrical power, which is supplied to said AC electric motor for driving said AC electric motor; and

a control device including control means for controlling driving of said AC electric motor by controlling said inverter according to an instructed torque received from a vehicle for said AC electric motor,

wherein, with said storage device not at or near a state of full charge, a split-second large current by which the electrical power output of said AC electric motor becomes negative is generated, said capacitor cannot accept all electric energy, the electrical power output of said AC electric motor becomes negative, and excess electrical energy is generated, and

wherein said control device controls the current applied to said AC electric motor such that the loss in said AC electric motor exceeds the negative electrical power output of said AC electric motor.