POWER SYSTEM AND METHOD FOR MANAGING CHARGING STATE IN THAT POWER SYSTEM

• US 20090315512A1
• Filed: 07/04/2007
• Published: 12/24/2009
• Est. Priority Date: 08/04/2006
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ishikawa, Tetsuhiro, Ichikawa, Shinji
• Granted Patent: US 7,847,518 B2
• Time in Patent Office: Days
• US Class Current: 320/109
• 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 53/305 Communication interfaces
• CPC Class Codes: B60L 53/66 Data transfer between charging stations and vehicles
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 3/322 the battery being on-board an electric or hybrid vehicle, e.g. vehicle to grid arrangements [V2G], power aggregation, use of the battery for network load balancing, coordinated or cooperative battery charging
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• 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 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 30/12 Remote or cooperative charging
• CPC Class Codes: Y04S 30/14 Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing

Abstract

Generation power determining unit specifies efficiency characteristic based on identification ID of each vehicle. Generation power determining unit determines a power generation mechanism or mechanisms to be operated such that amount of power consumption by the power generation mechanism or mechanisms as a whole is minimized. By dividing power ΣPg* necessary for charging an electric storage unit that is in a low-charge state by the number of mechanisms to be operated (for example, 2 or 3), fuel consumption efficiency corresponding to generation power to be shared by each power generation mechanism in each case is obtained. There is a relation of η(½)>η(⅓) and, therefore, it can be understood that two power generation mechanisms are to be operated to minimize total amount of fuel consumption. Generation power determining unit transmits a power generation instruction to vehicles that correspond to the determined two power generation mechanisms.

Claims

1. A power system, comprising:

a plurality of vehicles each adapted to allow transfer of power to/from the outside of the vehicle;

a power line for electrically connecting said plurality of vehicles to each other; and

power management means for managing power exchange among said plurality of vehicles;

wherein

said power management means is adapted to allow transmission/reception of information to/from each of said plurality of vehicle;

each of said plurality of vehicles includes;

a rechargeable electric storage unit,

a power generation mechanism capable of generating power by receiving driving force from an engine operated by fuel combustion,

state of charge obtaining means for obtaining state of charge of said electric storage unit,

state of charge transmitting means for transmitting the obtained state of charge to said power management means, and

power generation control means for controlling power generation by said power generation mechanism, in response to a power generation instruction from said power management means;

said power management means includes;

necessary power calculating means for calculating, if there is any electric storage unit that is in a low-charge state, based on said state of charge transmitted from each of said plurality of vehicles, power necessary for charging the electric storage unit that is in the low-charge state,

generation power determining means for determining at least one power generation mechanism to be operated for generating the power calculated by said necessary power calculating means, such that amount of fuel consumption by the power generation mechanism as a whole is minimized, and

power generation instruction transmitting means for applying said power generation instruction to the vehicle that corresponds to each of the determined power generation mechanisms.

2. The power system according to claim 1, wherein

said generation power determining means determines number of said power generation mechanisms to be operated, based on efficiency characteristic obtained in advance, representing correspondence between generation power of each of said power generation mechanisms and fuel consumption efficiency of said engine, such that fuel consumption efficiency of power generation mechanism or mechanisms to be operated as a whole is maximized.

3. The power system according to claim 1, wherein

said generation power determining means determines generation power to be shared by each of said power generation mechanisms to be operated, based on efficiency characteristic obtained in advance, representing correspondence between generation power of each of said power generation mechanisms and fuel consumption efficiency of said engine, such that fuel consumption efficiency of power generation mechanism or mechanisms to be operated as a whole is maximized.

4. The power system according to claim 2, wherein

each of said plurality of vehicles further includes identification information transmitting means for transmitting identification information representing itself to said power management means;

said identification information transmitting means further includes efficiency characteristics storing means for storing in advance said efficiency characteristic in correspondence with each piece of said identification information; and

said generation power determining means specifies said efficiency characteristic of each of said plurality of vehicles among a plurality of said stored efficiency characteristics, based on said identification information transmitted from each of said plurality of vehicles.

5. The power system according to claim 2, wherein

said power line is electrically connected, in order to allow power exchange between said plurality of vehicles and a common power load, to said power load;

said power management means further includes load power obtaining means for obtaining load power to be supplied to said power load; and

said necessary power calculating means calculates said necessary power by reflecting the load power obtained by said load power obtaining means.

6. The power system according to claim 1, wherein

said power management means and each of said plurality of vehicles are adapted to transmit/receive information through said power line.

7. The power system according to claim 1, wherein

at least one of said plurality of vehicles includes;

first and second rotating electrical machines each formed to include a star-connected stator, and

first and second inverters electrically connected to said electric storage unit for driving said first and second rotating electrical machines, respectively, and

the at least one vehicle is adapted to perform power exchange to/from the outside of said vehicle, through a first neutral point of said first rotating electrical machine and a second neutral point of said second rotating electrical machine, and

each of said first and second inverters is capable of executing a switching operation such that a single-phase AC voltage is generated between said first neutral point and said second neutral point.

13. The power system according to claim 3, wherein

each of said plurality of vehicles further includes identification information transmitting means for transmitting identification information representing itself to said power management means;

said identification information transmitting means further includes efficiency characteristics storing means for storing in advance said efficiency characteristic in correspondence with each piece of said identification information; and

said generation power determining means specifies said efficiency characteristic of each of said plurality of vehicles among a plurality of said stored efficiency characteristics, based on said identification information transmitted from each of said plurality of vehicles.

8. A power system, comprising:

a plurality of vehicles each adapted to allow transfer of power to/from the outside of the vehicle;

a power line for electrically connecting said plurality of vehicles to each other; and

a power management device for managing power exchange among said plurality of vehicles;

wherein

said power management device is adapted to allow transmission/reception of information to/from each of said plurality of vehicles;

each of said plurality of vehicles includes;

a rechargeable electric storage unit,

a power generation mechanism capable of generating power by receiving driving force from an engine operated by fuel combustion,

a state of charge obtaining unit for obtaining state of charge of said electric storage unit,

a state of charge transmitting unit for transmitting the obtained state of charge to said power management device, and

a power generation control unit for controlling power generation by said power generation mechanism, in response to a power generation instruction from said power management device;

said power management device is operative to;

calculate, if there is any electric storage unit that is in a low-charge state, based on said state of charge transmitted from each of said plurality of vehicles, power necessary for charging the electric storage unit that is in the low-charge state,

determine at least one power generation mechanism to be operated for generating the calculated necessary power, such that amount of fuel consumption by the power generation mechanism as a whole is minimized, and

apply said power generation instruction to the vehicle that corresponds to each of the determined power generation mechanisms.

9. For a plurality of vehicles each including a rechargeable electric storage unit, a method of managing state of charge of said electric storage unit;

wherein

each of said plurality of vehicles is adapted to allow transfer of power to/from the outside of the vehicle, electrically connected to each other through a power line, and adapted to allow transmission/reception of information to/from a power management unit, and

each of said plurality of vehicles includes a power generation mechanism capable of generating power, by receiving driving force from an engine operated by fuel combustion;

said method comprising the steps of;

for each of said plurality of vehicles, obtaining state of charge of corresponding said electric storage unit;

transmitting the obtained state of charge from each of said plurality of vehicles to said power management unit;

calculating, if there is any electric storage unit that is in a low-charge state, based on the state of charge transmitted from each of said plurality of vehicles to said power management unit, power necessary for charging the electric storage unit that is in the low-charge state;

determining, by said power management unit, at least one power generation mechanism to be operated for generating the necessary power, such that total amount of fuel consumption is minimized;

applying a power generation instruction from said power management unit, to the vehicle corresponding to each of the determined power generation mechanisms; and

controlling power generation by corresponding the power generation mechanism, in response to said power generation instruction, in the vehicle receiving said power generation instruction.

10. The method of managing state of charge according to claim 9, wherein

in said step of determining power generation mechanism, the number of said power generation mechanisms to be operated is determined, based on efficiency characteristic obtained in advance, representing correspondence between generation power of each of said power generation mechanisms and fuel consumption efficiency of said engine, such that fuel consumption efficiency of power generation mechanism or mechanisms to be operated as a whole is maximized.

11. The method of managing state of charge according to claim 9, wherein

in said step of determining power generation mechanism, generation power to be shared by each of said power generation mechanisms to be operated is determined, based on efficiency characteristic obtained in advance, representing correspondence between generation power of each of said power generation mechanisms and fuel consumption efficiency of said engine, such that fuel consumption efficiency of power generation mechanism or mechanisms to be operated as a whole is maximized.

12. The method of managing state of charge according to claim 10, further comprising the steps of:

each of said plurality of vehicles transmitting identification information representing itself to said power management unit; and

based on said identification information transmitted from each of said plurality of vehicles, said power management unit specifying said efficiency characteristic of each of said plurality of vehicles, making reference to a plurality of said efficiency characteristics stored in advance in correspondence with said identification information.

14. The method of managing state of charge according to claim 11, further comprising the steps of:

each of said plurality of vehicles transmitting identification information representing itself to said power management unit; and

based on said identification information transmitted from each of said plurality of vehicles, said power management unit specifying said efficiency characteristic of each of said plurality of vehicles, making reference to a plurality of said efficiency characteristics stored in advance in correspondence with said identification information.