ELECTRICALLY POWERED VEHICLE AND METHOD FOR CONTROLLING THE SAME

• US 20130264975A1
• Filed: 12/20/2010
• Published: 10/10/2013
• Est. Priority Date: 12/20/2010
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kaita, Keiji, Ishishita, Teruo, Nishi, Yuji, Takagi, Masaru, Okamura, Masaki
• Granted Patent: US 9,166,515 B2
• Time in Patent Office: Days
• US Class Current: 318/139
• CPC Class Codes: B60L 15/007 Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 50/66 Arrangements of batteries
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• 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

Abstract

A converter is disposed between a first battery and a power line for transmitting power inputted to and outputted from a motor for traveling. A second battery, on the other hand, is connected to the power line with a relay being interposed therebetween. A control unit controls the relay to be turned on or off in accordance with an operating state of the motor.

Claims

1. An electrically powered vehicle comprising:

a motor for generating vehicle driving force;

a first power storage device;

a second power storage device;

a power line for transmitting power inputted to and outputted from said motor;

a converter for carrying out bidirectional DC voltage conversion between said first power storage device and said power line;

a switch connected between said second power storage device and said power line; and

a control unit for controlling said switch to be turned on or off in accordance with an operating state of said motor.

2. The electrically powered vehicle according to claim 1, wherein

said control unit calculates a minimum required voltage of said power line in accordance with a torque and a rotation speed of said motor, and turns off said switch when an output voltage of said second power storage device is lower than said minimum required voltage.

3. The electrically powered vehicle according to claim 2, wherein

said control unit sets a voltage command value of said power line in a range not lower than said minimum required voltage in accordance with the torque and the rotation speed of said motor, and turns on said switch when the output voltage of said second power storage device is higher than said voltage command value, while it turns off said switch when said output voltage is lower than said voltage command value.

4. The electrically powered vehicle according to claim 3, wherein

said control unit turns off said switch when a voltage difference obtained by subtracting said voltage command value from the output voltage of said second power storage device is greater than a predetermined threshold value.

5. The electrically powered vehicle according to claim 1, wherein

said control unit turns off said switch when a charge level of said second power storage device becomes lower than a predetermined value.

6. The electrically powered vehicle according to claim 1, wherein

said control unit sets, when said switch is turned off, charge and discharge power upper limit values in entire said first and second power storage devices, based on charge and discharge power upper limit values of said first power storage device and a loss power value in said converter, and sets, when said switch is turned on, the charge and discharge power upper limit values in entire said first and second power storage devices, based on the charge and discharge power upper limit values of said first power storage device, charge and discharge power upper limit values of said second power storage device, and the loss power value in said converter.

7. The electrically powered vehicle according to claim 1, wherein

a rated value of an output voltage of said first power storage device is lower than a rated value of the output voltage of said second power storage device.

8. The electrically powered vehicle according to claim 1, wherein

said first power storage device has a power density higher than that of said second power storage device, and

said first power storage device has an energy density lower than that of said second power storage device.

9. A method for controlling an electrically powered vehicle mounted with a motor for generating vehicle driving force, a first power storage device, a second power storage device, and a converter for carrying out bidirectional DC voltage conversion between said first power storage device and a power line for transmitting power inputted to and outputted from said motor, comprising the steps of:

detecting an output voltage of said second power storage device; and

controlling a switch connected between said second power storage device and said power line to be turned on or off in accordance with an operating state of said motor.

10. The method for controlling an electrically powered vehicle according to claim 9, further comprising the step of:

calculating a minimum required voltage of said power line in accordance with a torque and a rotation speed of said motor, wherein

in said step of controlling, said switch is turned off when the output voltage of said second power storage device is lower than said minimum required voltage.

11. The method for controlling an electrically powered vehicle according to claim 10, wherein

in said step of calculating, a voltage command value of said power line is set in a range not lower than said minimum required voltage in accordance with the torque and the rotation speed of said motor, and

in said step of controlling, switch is turned on when the output voltage of said second power storage device is higher than said voltage command value, while said switch is turned off when said output voltage is lower than said voltage command value.

12. The method for controlling an electrically powered vehicle according to claim 11, wherein

in said step of controlling, said switch is turned off when a voltage difference obtained by subtracting said voltage command value from the output voltage of said second power storage device is greater than a predetermined threshold value.

13. The method for controlling an electrically powered vehicle according to claim 9, further comprising the step of turning off said switch when a charge level of said second power storage device becomes lower than a predetermined value.