Determination of stator winding resistance in an electric machine

An electric machine assembly comprising:

• an electric machine including a stator and a rotor, the stator having stator windings at a stator winding temperature (ts) and the rotor being configured to rotate at a rotor speed (ω);
• wherein the electric machine defines a number of pole pairs (P);
• a controller operatively connected to the electric machine and configured to receive a torque command (T*);
• wherein, the controller has a processor and tangible, non-transitory memory on which is recorded instructions for executing a method for determining stator winding resistance;
• wherein execution of the instructions by the processor causes the controller to determine a high-speed resistance factor (rH) for the stator windings, the high-speed resistance factor (rH) being based at least partially on the torque command (T*), the stator winding temperature (ts), the rotor speed (ω) and the number of pole pairs (P);
• wherein the controller is configured to determine a low-speed resistance factor (rL) for the stator windings based at least partially on a predefined wire coefficient (α), a measured stator resistance (r0) at a predefined measuring temperature (t0), and a temperature difference between the stator winding temperature (ts) and a predefined measuring temperature (t0) such that:
• rL=[r0(1+α×(ts−t0))];
• and
• wherein the controller is further configured to determine a total resistance (R) for the stator windings based at least partially on a weighting factor (k), the high-speed resistance factor (rH) and the low-speed resistance factor (rL) such that:
• R=[k×rH+(1−k)×rL] and 0<k<1.