Recuperative brake on a vehicle

• US 10,293,708 B2
• Filed: 04/19/2017
• Issued: 05/21/2019
• Est. Priority Date: 04/20/2016
• Status: Active Grant

• Current Assignee: Audi AG (Volkswagen AG)
• Original Assignee: Audi AG (Volkswagen AG)
• Inventors: Karl, Bernhard, Feldmann, Uwe, Winkelmeyr, Felix, Daschner, Rene, Heckel, Thomas
• Primary Examiner(s): Weber, Tamara L
• Application Number:
  US15/491,567
• Publication Number:
  US 20170305299A1
• Time in Patent Office: 762 Days
• Field of Search: None
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 15/2018 for braking on a slope
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2220/42 with use of more than one motor
• CPC Class Codes: B60L 2220/54 Windings for different functions
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/54 related to batteries
• CPC Class Codes: B60L 2260/22 Standstill, e.g. zero speed
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 7/18 Controlling the braking effect B60L7/12, B60L7/14, B60L7/16 take precedence
• CPC Class Codes: B60T 2270/60 Regenerative braking
• CPC Class Codes: B60T 8/17 Using electrical or electronic regulation means to control braking detecting or indicating faulty operation B60T8/885
• CPC Class Codes: B60W 30/00 Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
• 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 10/72 Electric energy management in electromobility

Abstract

The present invention relates to a method for recuperation based braking of a vehicle in which electrical energy generated during a braking process is decreased by operating at least one second electric machine of the vehicle in a zero slip mode in order to prevent overcharging of a traction battery of the vehicle.

Claims

1. A method for recuperation-based braking of a vehicle, comprising:

generating electrical energy with a first electric machine of the vehicle during a braking process;

operating with the electrical energy generated by the first electric machine a second electric machine in a zero slip mode in which a rotary field of a stator of the second electric machine synchronously follows a movement of a rotor of the second electric machine, so that no-load losses of the second electric machine are used to decrease the electrical energy generated by the first electric machine to thereby prevent overcharging of a traction battery of the vehicle; and

performing the zero slip mode operation for a predetermined period of time or up to a predetermined threshold value of a state of charge of the traction battery of the vehicle until a driver requests a torque from the first electric machine or the second electric machine.

2. The method of claim 1, further comprising prior to the decreasing step transferring the electrical energy to a buffer storage.

3. The method of claim 2, wherein the buffer storage is configured as a part of the traction battery of the vehicle, said method further comprising dynamically discharging the buffer storage by operating the second electric machine of the vehicle in the zero slip mode when the vehicle is operated in a free mode.

4. The method of claim 2, wherein the second electric machine is identical to the first electric machine.

5. The method of claim 1, wherein the first electric machine is assigned to a first one of at least two electrically driven axles of the vehicle, and the second electric machine is assigned to a second one of the at least two electrically driven axles of the vehicle.

6. The method of claim 5, wherein the electrical energy generated by the first electric machine is directly decreased by the second electric machine.

7. The method of claim 5, wherein an amount of the electrical energy generated by the first electric machine corresponds exactly to an amount of electrical energy that can subsequently be decreased by the second electric machine.