Method and device for operating an electric machine of a motor vehicle drive train

• US 9,649,953 B2
• Filed: 10/04/2011
• Issued: 05/16/2017
• Est. Priority Date: 12/06/2010
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Kanth, Daniel, Niemann, Holger, Heyl, Andreas, Schleser, Roland
• Primary Examiner(s): JABR, FADEY S
• Assistant Examiner(s): Mahne, Kevin P
• Application Number:
  US13/992,043
• Publication Number:
  US 20130317686A1
• Time in Patent Office: 2,051 Days
• Field of Search: None
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: H02P 29/032 Preventing damage to the motor, e.g. setting individual current limits for different drive conditions
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A method for operating an electrical machine, in particular for making available drive power for a drive train of a motor vehicle, the electrical machine being controlled by several phase currents, the method including sensing an electrical variable that represents the torque delivered by the electrical machine; and monitoring the torque. A degradation of the electrical machine is taken into consideration in the monitoring of the torque.

Claims

1. A method for operating an electrical machine for making available drive power for a drive train of a motor vehicle, the electrical machine being controlled by several phase currents, the method comprising:

sensing a first electrical variable that represents torque delivered by the electrical machine;

sensing a second electrical variable that represents a DC voltage power supplied to an inverter to generate the phase currents;

monitoring the torque by comparing the first sensed electrical variable to a maximum threshold torque value, wherein a degradation of the electrical machine is taken into consideration in the monitoring of the torque;

further monitoring the torque by performing a plausibility check based on the first sensed electrical variable and the second sensed electrical variable;

generating a current, wherein the degradation of the electrical machine is taken into consideration and;

controlling the electrical machine with the current to compensate for the degradation of the electrical machine.

2. The method as recited in claim 1, wherein a maximum value of the electrical variable is modified as a function of the degradation of the electrical machine.

3. The method as recited claim 1, wherein at least one further electrical variable, with which an extent of the degradation is ascertained, is sensed.

4. The method as recited in claim 3, wherein at least one monitoring parameter is modified as a function of the ascertained extent of the degradation of the electrical machine.

5. The method as recited in claim 1, wherein one of:

i) at least one phase current, or ii) a cross current transformed therefrom, of the electrical machine is sensed as an electrical variable.

6. The method as recited in claim 1, wherein the sensing of the electrical variable is accomplished for a plurality of operating points of the electrical machine.

7. The method as recited in claim 1, wherein the sensing of a further electrical variable is accomplished for a plurality of operating points of the electrical machine.

8. A control unit for controlling an electrical machine for making available drive power for a drive train of a motor vehicle, the control unit configured to perform the following:

sense a first electrical variable that represents torque delivered by the electrical machine;

sense a second electrical variable that represents a DC voltage power supplied to an inverter to generate phase currents to control the electrical machine;

monitor the torque by comparing the first sensed electrical variable to a maximum threshold torque value, wherein a degradation of the electrical machine is taken into consideration in the monitoring of the torque;

further monitor the torque by performing a plausibility check based on the first sensed electrical variable and the second sensed electrical variable;

generate a current, wherein the degradation of the electrical machine is taken into consideration; and

control the electrical machine with the current in order to compensate for the degradation of the electrical machine.

9. A motor vehicle drive train having at least one electrical machine for making available drive power, and having a control unit for controlling the electrical machine, the control unit configured to perform the following:

sense a first electrical variable that represents torque delivered by the electrical machine;

sense a second electrical variable that represents a DC voltage power supplied to an inverter to generate the phase currents;

monitor the torque by comparing the first sensed electrical variable to a maximum threshold torque value, wherein a degradation of the electrical machine is taken into consideration in the monitoring of the torque;

further monitor the torque by performing a plausibility check based on the first sensed electrical variable and the second sensed electrical variable;

generate a current, wherein the degradation of the electrical machine is taken into consideration; and

control the electrical machine with the current in order to compensate for the degradation of the electrical machine.

10. A method for operating an electrical machine for making available drive power for a drive train of a motor vehicle, the electrical machine being controlled by several phase currents, the method comprising:

sensing a first electrical variable that represents torque delivered by the electrical machine;

sensing a second electrical variable that represents a DC voltage power supplied to an inverter to generate the phase currents;

monitoring the torque by comparing the first sensed electrical variable to a maximum threshold torque value, wherein a degradation of the electrical machine is taken into consideration in the monitoring of the torque, and wherein one of;

i) at least one phase current, or ii) a cross current transformed therefrom, of the electrical machine is sensed as an electrical variable;

further monitoring the torque by performing a plausibility check based on the first sensed electrical variable and the second sensed electrical variable;

generating a current, wherein the degradation of the electrical machine is taken into consideration; and

controlling the electrical machine with the current to compensate for the degradation of the electrical machine.