US-12620877-B2 - Propulsion system with dual-wound electric motor and dual inverter configuration

US12620877B2US 12620877 B2US12620877 B2US 12620877B2US-12620877-B2

Abstract

A propulsion system for a vehicle includes an electric motor configured to generate torque to propel the vehicle. The electric motor has a stator assembly with a plurality of stator slots defining slot layers along a respective slot axis. A first plurality of conductors is at least partially positioned in the plurality of stator slots and forming a first winding set. A second plurality of conductors is at least partially positioned in the plurality of stator slots and forms a second winding set. A first inverter is adapted to drive the electric motor, the first winding set being coupled to the first inverter. A second inverter is adapted to drive the electric motor, the second winding set being coupled to the second inverter. The system includes a controller adapted to control operation of the first and second inverters based in part on a motor speed of the electric motor.

Inventors

Mazharul CHOWDHURY
Mohammad F. Momen
Khorshed Mohammed Alam
Alexander FORSYTH
Yilun Luo

Assignees

GM Global Technology Operations LLC

Dates

Publication Date: 20260505
Application Date: 20231005

Claims (20)

1 . A propulsion system comprising: an electric motor having a stator assembly with a plurality of stator slots defining slot layers along a respective slot axis; a first plurality of conductors at least partially positioned in the plurality of stator slots, the first plurality of conductors forming a first winding set; a second plurality of conductors at least partially positioned in the plurality of stator slots, the second plurality of conductors forming a second winding set; a first inverter adapted to drive the electric motor, the first winding set being coupled to the first inverter; a second inverter adapted to drive the electric motor, the second winding set being coupled to the second inverter; a controller having a processor and tangible, non-transitory memory on which instructions are recorded, the controller being adapted to control operation of the first inverter and the second inverter based in part on a motor speed of the electric motor; and wherein: the first plurality of conductors is interleaved with the second plurality of conductors along the respective slot axis; the first plurality of conductors extends a first conductor length along the respective slot axis and the second plurality of conductors extends a second conductor length along the slot axis, the first conductor length being smaller than the second conductor length; and at least one of the second plurality of conductors incorporates a split configuration having two equal conductor segments.
2 . The propulsion system of claim 1 , wherein the first inverter and the second inverter are both three-level inverters.
3 . The propulsion system of claim 1 , wherein the first inverter is adapted to carry a first current, the second inverter is adapted to carry a second current, and operation of the first inverter and the second inverter is controlled such that: the first current is greater than the second current when the motor speed is above a predefined threshold; and the second current is greater than the first current when the motor speed is below the predefined threshold.
4 . The propulsion system of claim 3 , wherein the second current is 5% higher than the first current.
5 . The propulsion system of claim 1 , wherein each of the first plurality of conductors is radially inwards relative to each of the second plurality of conductors along the respective slot axis such that the first plurality of conductors is closer to an air gap of the stator assembly.
6 . The propulsion system of claim 1 , wherein the split configuration extends along a radial direction parallel to the respective slot axis.
7 . The propulsion system of claim 1 , wherein the split configuration extends along a circumferential direction perpendicular to the respective slot axis.
8 . A method of operating a propulsion system in a vehicle, the propulsion system having an electric motor configured to generate torque, and a controller having a processor and tangible, non-transitory memory, the method comprising: incorporating a stator assembly in the electric motor with a plurality of stator slots defining slot layers along a respective slot axis; forming a first winding set by positioning a first plurality of conductors in the plurality of stator slots; forming a second winding set by positioning a second plurality of conductors in the plurality of stator slots; coupling the first winding set to a first inverter adapted to drive the electric motor; coupling the second winding set to a second inverter adapted to drive the electric motor; and controlling operation of the first inverter and the second inverter based in part on a motor speed of the electric motor, via the controller, including setting the first current to be greater than the second current when the motor speed is above a predefined threshold, and setting the second current to be greater than the first current when the motor speed is below the predefined threshold.
9 . The method of claim 8 , further comprising: positioning each of the first plurality of conductors to be radially inwards relative to each of the second plurality of conductors along the respective slot axis such that the first plurality of conductors is closer to an air gap of the stator assembly, the first plurality of conductors and the second plurality of conductors defining different conductor lengths.
10 . The method of claim 8 , further comprising: positioning each of the first plurality of conductors to be radially inwards relative to each of the second plurality of conductors along the respective slot axis such that the first plurality of conductors is closer to an air gap of the stator assembly, the first plurality of conductors and the second plurality of conductors defining an equal conductor length.
11 . The method of claim 8 , further comprising: interleaving the first plurality of conductors with the second plurality of conductors along the respective slot axis, the first plurality of conductors extending a first conductor length along the respective slot axis and the second plurality of conductors extends a second conductor length along the slot axis, the first conductor length being smaller than the second conductor length; and incorporating a split configuration in at least one of the second plurality of conductors, the split configuration being defined by two equal conductor segments.
12 . A vehicle comprising: an electric motor having a stator assembly with a plurality of stator slots defining slot layers along a respective slot axis, the electric motor being configured to generate torque for propulsion; a first plurality of conductors at least partially positioned in the plurality of stator slots and forming a first winding set; a second plurality of conductors at least partially positioned in the plurality of stator slots and forming a second winding set; a first inverter adapted to drive the electric motor, the first winding set being coupled to the first inverter; a second inverter adapted to drive the electric motor, the second winding set being coupled to the second inverter; and a controller having a processor and tangible, non-transitory memory on which instructions are recorded, the controller being adapted to control operation of the first inverter and the second inverter based in part on a motor speed of the electric motor; wherein the first inverter is adapted to carry a first current and the second inverter is adapted to carry a second current, operation of the first inverter and the second inverter being controlled such that: the first current is greater than the second current when the motor speed is above a predefined threshold; and the second current is greater than the first current when the motor speed is above a predefined threshold.
13 . The vehicle of claim 12 , wherein: each of the first plurality of conductors is radially inwards relative to each of the second plurality of conductors along the respective slot axis such that the first plurality of conductors is closer to an air gap of the stator assembly; and the first plurality of conductors and the second plurality of conductors define an equal conductor length.
14 . The vehicle of claim 12 , wherein: each of the first plurality of conductors is radially inwards relative to each of the second plurality of conductors along the respective slot axis such that the first plurality of conductors is closer to an air gap of the stator assembly; and the first plurality of conductors extends a first conductor length along the respective slot axis and the second plurality of conductors extends a second conductor length along the slot axis, the first conductor length being smaller than the second conductor length.
15 . The vehicle of claim 12 , wherein: the first plurality of conductors is interleaved with the second plurality of conductors along the respective slot axis; the first plurality of conductors extends a first conductor length along the respective slot axis and the second plurality of conductors extends a second conductor length along the slot axis, the first conductor length being smaller than the second conductor length; and at least one of the second plurality of conductors incorporates a split configuration having two equal conductor segments.
16 . The vehicle of claim 15 , wherein the split configuration extends along a circumferential direction perpendicular to the respective slot axis.
17 . The vehicle of claim 15 , wherein the split configuration extends along a radial direction parallel to the respective slot axis.
18 . The vehicle of claim 12 , wherein the first inverter and the second inverter are both three-level inverters.
19 . The vehicle of claim 12 , wherein the second current is 5% higher than the first current.
20 . The vehicle of claim 12 , wherein the first plurality of conductors and the second plurality of conductors define an equal conductor length.

Description

INTRODUCTION The disclosure relates generally to a propulsion system for a vehicle having an electric motor. More particularly, the disclosure relates to a propulsion system having a dual-wound electric motor and dual inverter configuration. An electric machine typically includes a stator having a plurality of stator windings and a rotor rotatable within the stator. In a generator mode, the rotation of the rotor induces voltage in the stator winding, which powers an external load such as charging a battery pack. Alternately, if an electric current is passed through the stator windings, the energized coils cause the rotor to rotate, and the machine will perform as a motor. Winding loss in the stator windings in a permanent magnet motor may become a challenging issue at various operating speeds. SUMMARY Disclosed herein is a propulsion system for a vehicle having an electric motor. The electric motor includes a stator assembly with a plurality of stator slots defining slot layers along a respective slot axis. A first plurality of conductors is at least partially positioned in the plurality of stator slots and forms a first winding set. A second plurality of conductors is at least partially positioned in the plurality of stator slots and forms a second winding set. The propulsion system includes a first inverter adapted to drive the electric motor, the first winding set being coupled to the first inverter. A second inverter is adapted to drive the electric motor, the second winding set being coupled to the second inverter. The system includes a controller having a processor and tangible, non-transitory memory on which instructions are recorded. The controller is adapted to control operation of the first inverter and the second inverter based in part on a motor speed of the electric motor. In one embodiment, the first inverter and the second inverter are both three-level inverters. The first inverter is adapted to carry a first current, and the second inverter is adapted to carry a second current. Operation of the first inverter and the second inverter may be controlled such that: the first current is greater than the second current when the motor speed is above a predefined threshold; and the second current is greater than the first current when the motor speed is below the predefined threshold. The second current may be about 5% higher than the first current. Each of the first plurality of conductors may be radially inwards relative to each of the second plurality of conductors along the respective slot axis such that the first plurality of conductors is closer to an air gap of the stator assembly. In a first embodiment, the first plurality of conductors extends a first conductor length along the respective slot axis and the second plurality of conductors extends a second conductor length along the slot axis, the first conductor length being smaller than the second conductor length. In a second embodiment, the first plurality of conductors and the second plurality of conductors define an equal conductor length. In a third embodiment, the first plurality of conductors may be interleaved with the second plurality of conductors along the respective slot axis. Here, the first plurality of conductors extends a first conductor length along the respective slot axis and the second plurality of conductors extends a second conductor length along the slot axis, with the first conductor length being smaller than the second conductor length. Here, at least one of the second plurality of conductors may incorporate a split configuration having two equal conductor segments. In one example, the split configuration extends along a radial direction parallel to the respective slot axis. In another example, the split configuration extends along a circumferential direction perpendicular to the respective slot axis. Disclosed herein is method of operating a propulsion system in a vehicle, the propulsion system having an electric motor configured to generate torque, and a controller having a processor and tangible, non-transitory memory. The method includes incorporating a stator assembly in the electric motor with a plurality of stator slots defining slot layers along a respective slot axis. The method includes forming a first winding set by positioning a first plurality of conductors in the plurality of stator slots, and forming a second winding set by positioning a second plurality of conductors in the plurality of stator slots. The method includes coupling the first winding set to a first inverter adapted to drive the electric motor, and coupling the second winding set to a second inverter adapted to drive the electric motor. Operation of the first inverter and the second inverter is controlled based in part on a motor speed of the electric motor, via the controller. The method may include setting the first current to be greater than the second current when the motor speed is above a predefined threshold, via the controller; and