Power control apparatus, electrically powered vehicle and power control method of power system

• US 20070069673A1
• Filed: 09/07/2006
• Published: 03/29/2007
• Est. Priority Date: 09/29/2005
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Oyobe, Hichirosai, Ishikawa, Tetsuhiro, Nakamura, Makoto, Sasaki, Shoichi
• Granted Patent: US 7,486,036 B2
• Time in Patent Office: Days
• US Class Current: 318/376
• CPC Class Codes: B60L 15/025 using field orientation; Vector control; Direct Torque Control [DTC]
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2220/54 Windings for different functions
• 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: B60L 7/22 Dynamic electric resistor braking, combined with dynamic electric regenerative braking
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• 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 2510/18 Braking system
• CPC Class Codes: B60W 30/18127 Regenerative braking
• 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

Abstract

When surplus power not charged to an electric storage is generated at the time of regenerative braking of a vehicle, a voltage is generated across first and second neutral points using a zero-voltage vector each of first and second inverters and the generated surplus power is consumed by a resistance connected across the first and second neutral points. The voltage generated across the first and second neutral points is calculated in accordance with the surplus voltage, using a resistance value of the resistance.

Claims

1. A power control apparatus, comprising:

a first poly-phase AC electric motor including a star-connected first poly-phase winding as a stator winding;

a second poly-phase AC electric motor including a star-connected second poly-phase winding as a stator winding;

an electric storage charged by regenerative power generated by at least one of said first and second poly-phase AC electric motors;

an electric load electrically connected between a first neutral point of said first poly-phase winding and a second neutral point of said second poly-phase winding; and

voltage control means for calculating surplus power corresponding to remainder obtained by subtracting power charged in said electric storage from said regenerative power, and for controlling a voltage across said first and second neutral points in accordance with the calculated surplus power.

2. The power control apparatus according to claim 1, wherein

the power control apparatus is mounted on a vehicle,

said voltage control means calculates the surplus power corresponding to remainder obtained by subtracting power charged in said electric storage from said regenerative power generated by at least one of said first and second poly-phase AC electric motors using kinetic energy of said vehicle at the time of a braking operation of said vehicle.

3. The power control apparatus according to claim 2, wherein

said voltage control means calculates said regenerative power based on rotation number and reduction torque of the poly-phase AC electric motor performing regeneration using kinetic energy of the vehicle.

4. The power control apparatus according to claim 3, wherein

said voltage control means calculates said surplus power based on power difference between said calculated regenerative power and maximum charge power acceptable by said electric storage.

5. The power control apparatus according to claim 1, wherein

said voltage control means calculates a command value of a voltage to be generated across said first and second neutral points based on said calculated surplus power and a resistance value of said electric load, and controls the voltage across said first and second neutral points based on the calculated command voltage value.

6. The power control apparatus according to claim 1, further comprising

a connecting unit arranged between said electric load and said first and second neutral points, electrically connecting said first and second neutral points to said electric load in accordance with a command from said voltage control means;

wherein

said voltage control means outputs said command to said connecting unit when said surplus power is generated.

7. The power control apparatus according to claim 1, wherein

said voltage control means generates a voltage difference in accordance with said surplus power across said first and second neutral points, when said surplus power is generated.

8. An electrically powered vehicle, comprising:

a first poly-phase AC electric motor including a star-connected first poly-phase winding as a stator winding;

a second poly-phase AC electric motor including a star-connected second poly-phase winding as a stator winding;

a driving wheel mechanically linked to a rotation shaft of said second poly-phase AC electric motor;

an electric storage charged by regenerative power generated by at least one of said first and second poly-phase AC electric motors;

an electric load electrically connected between a first neutral point of said first poly-phase winding and a second neutral point of said second poly-phase winding; and

voltage control means for calculating surplus power corresponding to remainder obtained by subtracting power charged in said electric storage from said regenerative power generated by said second poly-phase AC electric motor using kinetic energy of the vehicle at the time of a braking operation of the vehicle, and for controlling a voltage across said first and second neutral points in accordance with the calculated surplus power.

9. A power control method for a power system, wherein

said power system includes

a first poly-phase AC electric motor including a star-connected first poly-phase winding as a stator winding,

a second poly-phase AC electric motor including a star-connected second poly-phase winding as a stator winding,

an electric storage charged by regenerative power generated by at least one of said first and second poly-phase AC electric motors,

an electric load electrically connected between a first neutral point of said first poly-phase winding and a second neutral point of said second poly-phase winding, and

first and second inverters respectively connected to said first and second poly-phase windings, and generating a voltage difference in accordance with a command voltage value across said first and second neutral points;

said power control method comprising;

a first step of calculating surplus power corresponding to remainder obtained by subtracting power charged in said electric storage from said regenerative power; and

a second step of calculating said command voltage value based on the calculated surplus voltage.

10. The power control method according to claim 9, wherein

said power system is mounted on a vehicle, in said first step, the surplus power corresponding to remainder obtained by subtracting power charged in said electric storage from said regenerative power generated by at least one of said first and second poly-phase AC electric motors using kinetic energy of said vehicle at the time of a braking operation of said vehicle is calculated.

11. The power control method according to claim 10, further comprising

a third step of calculating said regenerative power based on rotation number and reduction torque of the poly-phase AC electric motor performing regeneration using kinetic energy of the vehicle.

12. The power control method according to claim 11, wherein

in said first step, said surplus power is calculated based on power difference between the regenerative power calculated in said third step and maximum charge power acceptable by said electric storage.

13. The power control method according to claim 9, wherein

in said second step, said command voltage value is calculated based on the surplus power calculated in said first step and a resistance value of said electric load.

14. The power control method according to claim 9, wherein

said power system further includes

a connecting unit electrically connecting said first and second neutral points to said electric load in accordance with a given command;

said control method further comprising

a fourth step of outputting said command to said connecting unit when said surplus power is generated.

15. A power control apparatus, comprising:

a first poly-phase AC electric motor including a star-connected first poly-phase winding as a stator winding;

a second poly-phase AC electric motor including a star-connected second poly-phase winding as a stator winding;

an electric storage charged by regenerative power generated by at least one of said first and second poly-phase AC electric motors;

an electric load electrically connected between a first neutral point of said first poly-phase winding and a second neutral point of said second poly-phase winding;

first and second inverters respectively connected to said first and second poly-phase windings; and

a controller executing a series of operations;

wherein

said controller calculates surplus power corresponding to remainder obtained by subtracting power charged in said electric storage from said regenerative power;

generates a command voltage value for generating a voltage difference across said first and second neutral points based on the calculated surplus power; and

controls said first and second inverters such that a voltage difference in accordance with said command voltage value is generated across said first and second neutral points.

16. The power control apparatus according to claim 15, wherein

the power control apparatus is mounted on a vehicle,

said controller calculates the surplus power corresponding to remainder obtained by subtracting power charged in said electric storage from said regenerative power generated by at least one of said first and second poly-phase AC electric motors using kinetic energy of said vehicle at the time of a braking operation of said vehicle.

17. The power control apparatus according to claim 16, wherein

said controller calculates said regenerative power based on rotation number and reduction torque of the poly-phase AC electric motor performing regeneration using kinetic energy of the vehicle.

18. The power control apparatus according to claim 17, wherein

said controller calculates said surplus power based on power difference between said calculated regenerative power and maximum charge power acceptable by said electric storage.

19. The power control apparatus according to claim 15, wherein

said controller calculates said command voltage value based on said calculated surplus power and a resistance value of said resistance.

20. The power control apparatus according to claim 15, further comprising

a connecting unit arranged between said electric load and said first and second neutral points, electrically connecting said first and second neutral points to said electric load in accordance with a command from said controller;

wherein

said controller outputs said command to said connecting unit when said surplus power is generated.