Method of monitoring performance of an electric motor

A method of detecting a short in a stator winding of an electric propulsion motor of a vehicle, the method comprising:

• providing a control module having an algorithm operable thereon capable of:
• calculating an actual input power of the electric motor by multiplying a sensed voltage of the electric motor by a sensed current of the electric motor to obtain the actual input power;
• calculating an output power of the electric motor by multiplying a sensed output torque of the electric motor by a sensed rotational speed of the electric motor;
• calculating an efficiency of the electric motor based on the sensed output torque of the electric motor, the sensed rotational speed of the electric motor, a sensed temperature of the electric motor, and the sensed voltage of the electric motor;
• calculating an expected input power of the electric motor by dividing the calculated output power of the electric motor by the calculated efficiency of the electric motor;
• recursively calculating a power difference between the actual input power and the expected input power over at least one period of an electrical cycle of the electric motor to determine a variance in the power difference during the at least one period of the electrical cycle;
• comparing the variance in the power difference to a threshold value;
• and
• signaling a possible electrical short in the stator winding of the electric motor when the variance in the power difference is less than the threshold value.