Method and control device for controlling the waste heat generated by an electric vehicle

Patent metadata

Field	Value
Publication number	US-10183580-B2
Application number	US-201615333387-A
Country	US
Kind code	B2
Filing date	Oct 25, 2016
Priority date	Jun 16, 2014
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

A method and a system are provided for controlling waste heat generated by a motor vehicle having an electric drive including a rechargeable battery and an electric machine for driving the motor vehicle. The method includes determining the thermal load on at least two components of the electric drive; if a first electric component of the electric drive has a lower thermal load than a second electric component, actuating the electric drive such that the generation of waste heat in the first electric component increases and the generation of waste heat in the second electric component does not increase; and if the second electric component has a lower thermal load than the first electric component, actuating the electric drive such that the generation of waste heat in the second electric component increases and the generation of waste heat in the first electric component does not increase.

First claim

What is claimed is:

1. A method for controlling waste heat generated by a motor vehicle with an electric drive, wherein the electric drive comprises a rechargeable battery, an electric machine to drive the motor vehicle, and a drive control device that controls actuation of the electric machine with current from the rechargeable battery and/or charging of the rechargeable battery with current generated by the electric machine, the method comprising the acts of:
determining a thermal load of at least two components of the electric drive;
if a first electric component of the electric drive has a lower thermal load than a second electric component, actuating the electric drive such that generation of waste heat in the first electric component of the electric drive increases and generation of waste heat in the second electric component of the electric drive does not increase; and
if the second electric component of the electric drive has a lower thermal load than the first electric component, actuating the electric drive such that generation of waste heat in the second electric component of the electric drive increases and generation of waste heat in the first electric component of the electric drive does not increase;
wherein the actuating of the electric drive includes:
increasing a switching frequency of at least one of transistors of the drive control device if more waste heat is to be generated in the drive control device and less waste heat is to be generated in the electric machine; and
decreasing the switching frequency of at least one of the transistors of the drive control device if less waste heat is to be generated in the drive control device and more waste heat is to be generated in the electric machine; and

controlling the temperature of an interior of the motor vehicle with the waste heat generated by the components of the electric drive.

2. The method according to claim 1 , further comprising the acts of:
monitoring the temperature of the drive control device; and
actuating the electric drive such that the fluctuation of the temperature of the components of the drive control device is lower than a predetermined threshold value.

3. The method according to claim 1 , further comprising the act of:
supplying current by the drive control device such that a ratio of a field-generating current id and of a torque-generating current iq is outside of an optimum ratio of the field-generating current id and of the torque-generating current iq for a respective operating point.

4. The method according to claim 1 , further comprising one or more of the acts of:
applying a brake of the motor vehicle and actuating the electric drive such that it is to move the motor vehicle;
actuating the drive control device such that only a field-generating current id is supplied to the electric machine;
actuating the electric drive such that the drive control device actuates the electric machine such that a rotary field is generated in the electric machine without the axis of the electric machine rotating;
if the motor vehicle is at a standstill, actuating the electric drive such that the drive control device actuates the electric machine such that the electric machine generates a first torque in a first direction and thereafter generates a second torque in a second direction that is opposite to the first direction, wherein the motor vehicle is not moved away from where it is located by the first torque and the second torque;
if the motor vehicle moves, actuating the electric drive such that the drive control device actuates the electric machine such that the electric machine generates a first superimposed torque in the first direction and thereafter generates a second superimposed torque in the second direction, which is opposite to the first direction, wherein the first superimposed torque and the second superimposed torque are superimposed on a rotary movement of the electric machine and the motor vehicle is not accelerated and not decelerated by the first superimposed torque and the second superimposed torque;
if a transmission of the motor vehicle is idling so that no torque is transmitted from the electric machine to a power wheel, actuating the electric drive such that the drive control device actuates the electric machine such that the electric machine generates a torque;
if the electric machine generates a torque for driving the motor vehicle, actuating the electric drive such that the drive control device supplies the electric machine with a higher field-generating current id than is required for the respective operating point; and
if the electric machine generates current, actuating the electric drive such that a higher field-generating current id flows from the electric machine to the drive control device.

5. A computer product, comprising a non-transitory computer readable medium having stored therein program code that, when executed by a processor, causes the processor to:
determine a thermal load of at least two components of an electric drive;
if a first electric component of the electric drive has a lower thermal load than a second electric component, actuate the electric drive such that generation of waste heat in the first electric component of the electric drive increases and generation of waste heat in the second electric component of the electric drive does not increase;
if the second electric component of the electric drive has a lower thermal load than the first electric component, actuate the electric drive such that generation of waste heat in the second electric component of the electric drive increases and generation of waste heat in the first electric component of the electric drive does not increase;
increase a switching frequency of at least one of transistors of a drive control device of the electric drive if more waste heat is to be generated in the drive control device and less waste heat is to be generated in an electric machine of the electric drive;
decrease the switching frequency of at least one of the transistors of the drive control device if less waste heat is to be generated in the drive control device and more waste heat is to be generated in the electric machine; and
control the temperature of an interior of a motor vehicle with the waste heat generated by the components of the electric drive.

6. A waste heat control system for a motor vehicle equipped with an electric drive comprising a rechargeable battery, an electric machine suppliable with current by the rechargeable battery, the electric machine driving the motor vehicle, and a drive control device that controls actuation of the electric machine with current from the rechargeable battery and/or charging of the rechargeable battery with current generated by the electric machine, wherein the waste heat control system includes a processor and associated non-transitory memory storing program code therein which, when executed, causes the processor to:
determine a thermal load of at least two components of the electric drive;
if a first electric component of the electric drive has a lower thermal load than a second electric component, actuate the electric drive such that generation of waste heat in the first electric component of the electric drive increases and generation of waste heat in the second electric component of the electric drive does not increase;
if the second electric component of the electric drive has a lower thermal load than the first electric component, actuate the electric drive such that generation of waste heat in the second electric component of the electric drive increases and generation of waste heat in the first electric component of the electric drive does not increase;
increase a switching frequency of at least one of transistors of the drive control device if more waste

Assignees

• Bayerische Motoren Werke Ag

Inventors

• Schedel Felix
• Griesbeck Michael
• Meinert Hajo
• Richter Jens
• Hofmann Philipp

Classifications

• B60K2001/006

  the electric motors · CPC title

• B60L3/0061 Primary

  relating to electrical machines · CPC title

• B60L2240/525

  Temperature of converter or components thereof · CPC title

• B60L2240/425

  Temperature · CPC title

• Y02T10/72

  Electric energy management in electromobility · CPC title