Stator winding diagnostic systems and methods

An electrical system comprising:

• an electric motor having stator windings, each stator winding corresponding to a respective phase of the electric motor;
• an inverter module coupled to the stator windings to provide commanded voltages from an energy source to the stator windings of the electric motor in response to voltage commands corresponding to the phases of the electric motor;
• a plurality of current sensors coupled between the inverter module and the stator windings to obtain measured currents through the stator windings;
• and
• a control module coupled to the inverter module and the plurality of current sensors to:
• generate the voltage commands corresponding to the commanded voltages based on a difference between the measured currents and commanded currents;
• determine an input energy difference between a first phase of the stator windings and a second phase of the stator windings based on the voltage commands and the measured currents for an electrical period of the electric motor;
• determine an input energy ratio for the first phase with respect to the second phase for the electrical period when the input energy difference is greater than a first threshold value;
• and
• identify a fault condition in the stator windings based on the input energy ratio and a second threshold value.

A method for diagnosing stator windings in an electric motor, the method comprising:

• determining, by a control module coupled to a first module coupled between the electric motor and an energy source, a first motor phase input energy metric for a first phase of the stator windings of the electric motor for an electrical period of the electric motor by accumulating a first plurality of instantaneous input power values for the first phase during the electrical period;
• determining, by the control module, a second motor phase input energy metric for a second phase of stator windings of the electric motor for the electrical period of the electric motor by accumulating a second plurality of instantaneous input power values for the second phase during the electrical period, wherein each respective instantaneous input power value of the second plurality is concurrent to a respective instantaneous input power value of the first plurality;
• determining, by the control module, an input energy ratio for the first phase with respect to the second phase for the electrical period when an input energy difference between the first motor phase input energy metric and the second motor phase input energy metric is greater than a first threshold value;
• and
• identifying, by the control module, a short circuit fault condition based on the input energy ratio and a second threshold value when the difference between the first motor phase input energy metric and the second motor phase input energy metric is greater than the first threshold value.