Controlling magnetic flux in an automotive electric machine

• US 9,673,742 B2
• Filed: 04/21/2014
• Issued: 06/06/2017
• Est. Priority Date: 04/21/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Hanson, Kyle M., Haran, Edward W.
• Primary Examiner(s): Chan, Kawing
• Assistant Examiner(s): BROWN, BRADLEY R
• Application Number:
  US14/257,194
• Publication Number:
  US 20150303837A1
• Time in Patent Office: 1,142 Days
• Field of Search: 318 46
• CPC Class Codes: H02K 17/36 with another asynchronous induction motor
• CPC Class Codes: H02P 21/14 Estimation or adaptation of machine parameters, e.g. flux, current or voltage
• CPC Class Codes: H02P 5/747 mechanically coupled by gearing
• CPC Class Codes: H02P 6/08 Arrangements for controlling the speed or torque of a single motor H02P6/10, H02P6/28 take precedence
• CPC Class Codes: H02P 6/10 Arrangements for controlling torque ripple, e.g. providing reduced torque ripple
• CPC Class Codes: H02P 9/00 Arrangements for controlling electric generators for the purpose of obtaining a desired output

Abstract

A method of compensating for magnetic flux resulting from variance from a first electric machine to a second electric machine. A magnetic flux change for the first machine is calculated as a function of a flux difference between the first machine and the second machine. Operation of the first machine is controlled using the magnetic flux change.

Claims

1. A method of controlling an automotive electric machine comprising:

adjusting operation of the machine based on a magnetic flux change for the machine that is a function of a back electromotive force of the machine compared to a baseline back electromotive force, and adjusting operation of the machine based on multiplying a predetermined d-axis current command by a d-axis current change; and

wherein the d-axis current change (Δ

Id) is (−

Δ

λ

m/Ld)(Taper_DeltaId), where Δ

λ

m is the magnetic flux change, Ld is a d-axis inductance of the machine, and Taper_DeltaId is 1.0 when a full voltage is applied to the machine and (M_Index−

M_Index_Min)/(M_Index_Max−

M_Index_Min), when less than a full voltage is applied to the machine, where M_Index is a normalized commanded voltage magnitude, M_Index_Min is a minimum normalized commanded voltage magnitude, and M_Index_Max is a maximum normalized commanded voltage magnitude.

2. The method of claim 1 wherein the magnetic flux is a function of a variance between the machine and a benchmark machine, which is not drivingly connected to the first machine.

3. The method of claim 2 wherein the magnetic flux is additionally a function of a temperature of the machine.

4. The method of claim 1 wherein a current command adjustment is a function of the magnetic flux change and a voltage magnitude.

5. The method of claim 1 wherein operation of the machine is controlled by adjusting a torque command.

6. The method of claim 5 wherein the torque command adjustment is a function of the magnetic flux change, an inductance difference, and a current change.

7. The method of claim 6 wherein the current change is a function of the magnetic flux change and a voltage magnitude.

8. The method of claim 1 wherein the machine is controlled to provide a torque to an automotive powertrain.