METHOD FOR DETERMINING A COIL TEMPERATURE OF AN ELECTRIC MACHINE

• US 20160131534A1
• Filed: 11/04/2015
• Published: 05/12/2016
• Est. Priority Date: 11/06/2014
• Status: Active Grant

• Current Assignee: Audi AG (Volkswagen AG)
• Original Assignee: Audi AG (Volkswagen AG)
• Inventors: Karl, Bernhard
• Granted Patent: US 10,295,414 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01K 2205/00 Application of thermometers in motors, e.g. of a vehicle
• CPC Class Codes: G01K 2217/00 Temperature measurement using electric or magnetic components already present in the system to be measured
• CPC Class Codes: G01K 7/00 Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat giving results other than momentary value of temperature G01K3/00 ; Power supply therefor, e.g. using thermoelectric elements
• CPC Class Codes: G01K 7/16 using resistive elements resistive elements per se H01C, H01L

Abstract

A method for determining an actual temperature of a coil of an electric machine, includes detecting a voltage in a no-load state of the electric machine; detecting a current strength in an induced short circuit state of the electric machine; calculating an actual stator coil resistance as a function of the voltage detected during the no-load state and the current strength detected during the active short circuit” state; and calculating the actual temperature of the coil of the electric machine as a function of the actual stator coil resistance.

Claims

1. A method for determining an actual temperature of a coil of an electric machine, comprising:

detecting a voltage in a no-load state of the electric machine;

detecting a current strength in an induced short circuit state of the electric machine;

calculating an actual stator coil resistance as a function of the voltage detected during the no-load state and the current strength detected during the active short circuit”

state; and

calculating the actual temperature of the coil of the electric machine as a function of the actual stator coil resistance.

2. The method of claim 1, further comprising calculating a magnetic flux during the no-load state as a function of the detected voltage, and during active short circuit state calculating the actual stator coil resistance as a function of the actual magnetic flux and the current strength detected during the active short circuit state.

3. The method of claim 1, further comprising switching electric machine into the state no-load state for determining the voltage and subsequently switching the electric machine into the state active short circuit state for determining the induced current.

4. The method of claim 3, further comprising driving a vehicle with the electric machine and switching the electric machine into the no-load state and/or the state active short circuit state during a trailing throttle mode of the vehicle.

5. The method of claim 4, wherein the vehicle is a hybrid vehicle comprising an internal combustion engine, and wherein the method further comprises driving the vehicle with the internal combustion engine when switching into the no-load state and/or the state active short circuit state.

6. The method of claim 1, further comprising inputting the determined temperature as a start value into a model for calculating an actual temperature of the electric machine.

7. A vehicle comprising a control device configured to determine an actual temperature of a coil of an electric machine, said control device being configured to calculate an actual stator coil resistance as a function of a voltage detected during a no-load state of the electric machine and a current strength detected during an active short circuit state of the electric machine, and to calculate the actual temperature of the coil of the electric machine as a function of the actual stator coil resistance.

8. The vehicle of claim 7, wherein the control device is configured to switch the electric machine into the no-load state and/or into the state active short circuit state.

9. The vehicle of claim 7, further comprising at least one sensor for detecting an induced voltage and/or current strength in the no-load state and/or into the state active short circuit state of the electric machine.

10. The vehicle according to one of the claim 7, wherein the electric machine is a three-phase electric machine.