Power supply system and vehicle including the same, and method of controlling the same

• US 7,923,866 B2
• Filed: 12/05/2007
• Issued: 04/12/2011
• Est. Priority Date: 01/04/2007
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ichikawa, Shinji, Sato, Eiji
• Primary Examiner(s): Fleming; Fritz M
• Application Number:
  US12/312,745
• Publication Number:
  US 20100065349A1
• Time in Patent Office: 1,224 Days
• Field of Search: 307/9.1, 307/10.1, 307/10.7, 307/25, 307/29, 307/82
• US Class Current: 307/82
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/20 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
• CPC Class Codes: B60K 6/26 characterised by the motors or the generators
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/526 Operating parameters
• CPC Class Codes: B60L 2270/20 Inrush current reduction, i.e. avoiding high currents when connecting the battery
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• 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 50/16 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 53/18 Cables specially adapted for charging electric vehicles
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/20 having different nominal voltages
• 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 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: H02J 1/082 Plural DC voltage, e.g. DC supply voltage with at least two different DC voltage levels
• CPC Class Codes: H02J 1/102 : being switching converters H02J1/108, H02J1/12 take precedence
• CPC Class Codes: H02J 3/0073 : for providing alternative feeding paths between load and source when the main path fails, e.g. transformers, busbars
• CPC Class Codes: H02J 7/34 : Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: H02M 1/10 : Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from ac or dc
• CPC Class Codes: H02P 2201/09 : Boost converter, i.e. DC-DC step up converter increasing the voltage between the supply and the inverter driving the motor general aspects of plural converters in cascade H02M
• 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 10/92 : Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles

Abstract

When power storage units and are both in a normal condition, system relays are maintained in an ON state. A converter performs a voltage conversion operation in accordance with a voltage control mode, and a converter performs a boost operation in accordance with an electric power control mode. If some kind of fault condition occurs in the power storage unit and the system relay is driven to an OFF state, the converters stop the voltage conversion operation and maintain an electrically conducting state between the power storage units and a main positive bus, a main negative bus.

Claims

1. A power supply system for supplying electric power to first and second load devices, comprising:

a first electric power line pair electrically connected to said first load device;

a plurality of rechargeable power storage units

a plurality of voltage conversion units arranged corresponding to said plurality of power storage units respectively, said plurality of voltage conversion units being connected in parallel to said first electric power line pair and each being configured to perform a voltage conversion operation between said first electric power line pair and corresponding said power storage unit;

a plurality of disconnection units arranged corresponding to said plurality of power storage units respectively, each for electrically disconnecting corresponding said power storage unit and corresponding said voltage conversion unit from each other;

a second electric power line pair having one end electrically connected between a first voltage conversion unit representing one of said plurality of voltage conversion units and corresponding said disconnection unit and another end electrically connected to said second load device; and

a control unit for controlling said plurality of voltage conversion units, when one disconnection unit among said plurality of disconnection units electrically disconnects corresponding said power storage unit and corresponding said voltage conversion unit from each other, such that electric power supply to said first load device and electric power supply to said second load device are continued through said first electric power line pair and through said second electric power line pair respectively by using electric power from remaining said power storage unit.

2. The power supply system according to claim 1, further comprising a fault condition detection unit for detecting a fault condition for each of said plurality of power storage units, wherein

each of said plurality of disconnection units is configured to electrically disconnect corresponding said power storage unit and corresponding said voltage conversion unit from each other in response to detection of a fault condition in corresponding said power storage unit by said fault condition detection unit.

3. The power supply system according to claim 2, wherein

said fault condition detection unit detects a fault condition of each of said plurality of power storage units based on at least one of a temperature, a voltage value, a current value, and an internal resistance value of corresponding said power storage unit.

4. The power supply system according to claim 1, wherein

said control unit controls said voltage conversion unit corresponding to remaining said power storage unit such that electric power from said remaining power storage unit is supplied to said first load device through said first electric power line pair and controls said first voltage conversion unit such that electric power is supplied from said first electric power line pair through said second electric power line pair to said second load device, when said first voltage conversion unit and corresponding said power storage unit are electrically disconnected from each other by corresponding said disconnection unit.

5. The power supply system according to claim 4, wherein

said control unit stops said voltage conversion operation between said first electric power line pair and corresponding said power storage unit and thereafter sets an electrically conducting state therebetween, for each of said plurality of voltage conversion units.

6. The power supply system according to claim 5, wherein

each of said plurality of voltage conversion units includes

a switching element connected in series to an inductor and arranged between one electric power line out of said first electric power line pair and one electrode of corresponding said power storage unit, capable of electrically connecting and disconnecting said one electric power line and said one electrode of corresponding said power storage unit to/from each other, and

a line for electrically connecting another electric power line out of said first electric power line pair and another electrode of corresponding said power storage unit to each other, and

said control unit maintains said conducting state by setting said switching element to an ON state, for each of said plurality of voltage conversion units.

7. The power supply system according to claim 4, wherein

said control unit controls remaining said voltage conversion unit except for said first voltage conversion unit such that electric power from corresponding said power storage unit is supplied to said first electric power line pair after it is boosted, and controls said first voltage conversion unit such that electric power from said first electric power line pair is supplied to said second load device after it is down-converted.

8. The power supply system according to claim 7, wherein

said control unit controls said first voltage conversion unit in accordance with a first control mode for attaining a value of a down-converted voltage supplied to said second load device to a prescribed target value.

9. The power supply system according to claim 7, wherein

said control unit controls at least one of said remaining voltage conversion units in accordance with a second control mode for attaining a value of a boosted voltage supplied to said first electric power line pair to a prescribed target value.

10. The power supply system according to claim 9, wherein

while said first voltage conversion unit and corresponding said power storage unit are electrically connected to each other, said first voltage conversion unit is set to said second control mode to perform a voltage conversion operation, and each said remaining voltage conversion unit is set to a third control mode for attaining a value of electric power supplied and received between said first electric power line pair and corresponding said power storage unit to a prescribed target value to perform a voltage conversion operation, and

said control unit switches between the control modes for at least one of said remaining voltage conversion units and said first voltage conversion unit in response to electrical disconnection between said first voltage conversion unit and corresponding said power storage unit by corresponding said disconnection unit.

11. A vehicle, comprising:

a power supply system for supplying electric power to first and second load devices; and

a drive force generation unit for generating drive force for running as said first load device;

said power supply system including

a first electric power line pair electrically connected to said first load device,

a plurality of rechargeable power storage units,

a plurality of voltage conversion units arranged corresponding to said plurality of power storage units respectively, said plurality of voltage conversion units being connected in parallel to said first electric power line pair and each being configured to perform a voltage conversion operation between said first electric power line pair and corresponding said power storage unit,

a plurality of disconnection units arranged corresponding to said plurality of power storage units respectively, each for electrically disconnecting corresponding said power storage unit and corresponding said voltage conversion unit from each other,

a second electric power line pair having one end electrically connected between a first voltage conversion unit representing one of said plurality of voltage conversion units and corresponding said disconnection unit and another end electrically connected to said second load device, and

a control unit for controlling said plurality of voltage conversion units, when one disconnection unit among said plurality of disconnection units electrically disconnects corresponding said power storage unit and corresponding said voltage conversion unit from each other, such that electric power supply to said first load device and electric power supply to said second load device are continued through said first electric power line pair and through said second electric power line pair respectively by using electric power from remaining said power storage unit.

12. The vehicle according to claim 11, further comprising an auxiliary machinery group for vehicle as said second load device.

13. A method of controlling a power supply system for supplying electric power to first and second load devices, said power supply system including

a first electric power line pair electrically connected to said first load device,

a plurality of rechargeable power storage units,

a plurality of voltage conversion units arranged corresponding to said plurality of power storage units respectively, said plurality of voltage conversion units being connected in parallel to said first electric power line pair and each being configured to perform a voltage conversion operation between corresponding said power storage unit and said first electric power line pair,

a plurality of disconnection units arranged corresponding to said plurality of power storage units respectively, each for electrically disconnecting corresponding said power storage unit and corresponding said voltage conversion unit from each other, and

a second electric power line pair having one end electrically connected between a first voltage conversion unit representing one of said plurality of voltage conversion units and corresponding said disconnection unit and another end electrically connected to said second load device,

said method comprising the steps of:

detecting whether a fault condition is present, for each of said plurality of power storage units;

electrically disconnecting, when the fault condition of any one power storage unit among said plurality of power storage units is detected, the power storage unit of which fault condition has been detected and corresponding said voltage conversion unit from each other by using corresponding said disconnection unit; and

controlling said plurality of voltage conversion units such that electric power supply to said first load device and electric power supply to said second load device are continued through said first electric power line pair and through said second electric power line pair respectively by using electric power from remaining power storage unit except for disconnected said power storage unit.