Method of operating a vehicle and electric powertrain

• US 8,502,410 B2
• Filed: 02/04/2010
• Issued: 08/06/2013
• Est. Priority Date: 02/04/2010
• Status: Expired due to Fees

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler AG (Mercedes-Benz Group AG)
• Inventors: Heller, Marcus, Nelson, Jody J.
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): Zhang, Haihui
• Application Number:
  US12/700,255
• Publication Number:
  US 20110186366A1
• Time in Patent Office: 1,279 Days
• Field of Search: 307/9.1, 180/65.1
• US Class Current: 307/10.1
• CPC Class Codes: B60L 1/00 Supplying electric power to auxiliary equipment of vehicles circuit arrangements for charging batteries H02J7/00
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2240/525 Temperature of converter or components thereof
• CPC Class Codes: B60L 7/003 Dynamic electric braking by short circuiting the motor
• CPC Class Codes: B60L 7/16 for vehicles comprising converters between the power source and the motor

Abstract

An electric powertrain comprises a high voltage bus an electric machine, and a traction inverter is coupled between a high voltage bus and the electric machine. An electric voltage for the high voltage bus is generated with the electric machine and the traction inverter when the electric machine is driven mechanically. The generated electric voltage is limited and converted to a predetermined voltage lower than the limited voltage. A unit of the vehicle, such as a cooling pump, is powered with the predetermined voltage.

Claims

1. A method of operating a vehicle having an electric powertrain comprising a high voltage bus, an electric machine, and a traction inverter coupled between the high voltage bus and the electric machine, the method comprising:

said electric machine and the traction inverter generating an electric voltage for the high voltage bus when the electric machine is driven mechanically;

limiting the generated electric voltage;

converting the limited voltage to a predetermined voltage lower than the limited voltage; and

powering a unit of the vehicle with said predetermined voltage;

wherein the generated electric voltage varies, according to a sawtooth pattern, between two pre-given voltage levels.

2. The method according to claim 1, wherein the generated electric voltage is limited to a maximum lower than 100 V.

3. The method according to claim 1, wherein a frequency of the generated electric voltage is determined by a discharge rate of the high voltage bus being disconnected from the electric machine.

4. The method according to claim 3, wherein the frequency of the generated electric voltage is less than 3 kHz.

5. The method according to claim 3, wherein the frequency of the generated electric voltage is less than 500 Hz.