Electric vehicle and control method of electric vehicle

• US 9,641,106 B2
• Filed: 01/08/2015
• Issued: 05/02/2017
• Est. Priority Date: 01/10/2014
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ota, Takashi, Sato, Ryoji, Suhama, Masayoshi
• Primary Examiner(s): Ro, Bentsu
• Assistant Examiner(s): Bouziane, Said
• Application Number:
  US14/592,330
• Publication Number:
  US 20150200613A1
• Time in Patent Office: 845 Days
• Field of Search: None
• CPC Class Codes: B60L 2220/12 Induction machines
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 7/00 Electrodynamic brake systems for vehicles in general
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/18 Controlling the braking effect B60L7/12, B60L7/14, B60L7/16 take precedence
• CPC Class Codes: B60L 7/24 with additional mechanical or electromagnetic braking
• CPC Class Codes: H02P 3/18 for stopping or slowing an ac motor
• CPC Class Codes: H02P 5/74 controlling two or more ac dynamo-electric motors H02P5/46, H02P5/60 take 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

Abstract

An electric vehicle driven by a synchronous motor 21 and an induction motor 31, and braked with a first regenerative torque BT₁ generated by the synchronous motor generator 21 and a second regenerative torque BT₂ generated by the induction motor generator 31. The ratio of the first regenerative torque BT₁ to the second regenerative torque BT₂ is changed in accordance with a state of charge (SOC) of a battery 11. In this way, a switching frequency from a regenerative brake to a hydraulic brake is restricted to improve drivability when a state of charge (SOC) of the battery 11 is high.

Claims

1. An electric vehicle comprising

a synchronous motor;

and

an induction motor;

wherein the electric vehicle is driven by the synchronous motor and the induction motor, and braked with a first regenerative torque generated by the synchronous motor and a second regenerative torque generated by the induction motor;

the electric vehicle further comprises a battery which supplies a drive electric power to the synchronous motor and the induction motor, and receives a regenerative electric power from the synchronous motor and the induction motor; and

a controller which adjusts the first regenerative torque and the second regenerative torque, and the controller includes a torque setting unit which changes a ratio of the first regenerative torque to the second regenerative torque in accordance with a state of charge of the battery.

2. The electric vehicle according to claim 1, wherein

when the state of charge of the battery is high, the torque ratio setting unit sets the proportion of the second regenerative torque is set higher than when the state of charge of the battery is low.

3. The electric vehicle according to claim 2, wherein

when the state of charge of the battery exceeds a first threshold, the torque ratio setting unit increases the proportion of the second regenerative torque and decreases the proportion of the first regenerative torque is decreased along with an increase of the state of charge of the battery.

4. The electric vehicle according to claim 3, wherein

when the state of charge of the battery is equal to or more than a second threshold, the torque ratio setting unit sets the proportion of the second regenerative torque at 100% and sets the proportion of the first regenerative torque at 0%.

5. The electric vehicle according to claim 4, wherein

the second threshold is the state of charge of the battery at which a limit starts to be applied to a maximum regenerative electric power of the battery, and the first threshold is smaller than the second threshold.

6. An electric vehicle comprising

a synchronous motor;

and

an induction motor;

wherein the electric vehicle is driven by the synchronous motor and the induction motor, and braked with a first regenerative torque generated by the synchronous motor and a second regenerative torque generated by the induction motor;

the electric vehicle further comprises

a battery which supplies a drive electric power to the synchronous motor and the induction motor, and receives a regenerative electric power from the synchronous motor and the induction motor; and

a controller including a CPU, and

the CPU of the controller executes a torque ratio setting program which changes a ratio of the first regenerative torque to the second regenerative torque in accordance with a state of charge of the battery.

7. The electric vehicle according to claim 6, wherein

when the state of charge of the battery is high, the CPU in the controller sets the proportion of the second regenerative torque higher than when the state of charge of the battery is low.

8. The electric vehicle according to claim 7, wherein when the state of charge of the battery exceeds a first threshold, the CPU in the controller increases the proportion of the second regenerative torque and decreases the proportion of the first regenerative torque along with an increase of the state of charge of the battery.

9. The electric vehicle according to claim 8, wherein

when the state of charge of the battery is equal to or more than a second threshold, the CPU in the controller sets the proportion of the second regenerative torque at 100% and sets the proportion of the first regenerative torque at 0%.

10. The electric vehicle according to claim 9, wherein the second threshold is the state of charge of the battery at which a limit starts to be applied to a maximum regenerative electric power of the battery, and the first threshold is smaller than the second threshold.

11. A controlling method of an electric vehicle including:

a synchronous motor;

an induction motor; and

a battery which supplies a drive electric power to the synchronous motor and the induction motor, and receives a regenerative electric power from the synchronous motor and the induction motor,

the controlling method comprising;

driving the electric vehicle by the synchronous motor and the induction motor, and braking with a first regenerative torque generated by the synchronous motor and a second regenerative torque generated by the induction motor; and

changing the ratio of the first regenerative torque to the second regenerative torque in accordance with a state of charge of the battery.