Gm Global Technolgoy Operations, Inc.

Chad A Freitas

Lei Hao

Steven Lee Hayslett

Matthew D Laba

Cristian A Lopez-Martinez

A method and system are disclosed for detecting turn-to-turn and phase-to-phase winding short circuits in an electric motor. The motor is tested at a standstill condition by injecting a current signal into the virtual d-axis of the motor while controlling q-axis current to zero. Steady state feedback current from the motor is measured, and current harmonics are calculated using FFT or peak-to-peak techniques. It is determined that a short circuit is present in the winding if feedback current harmonics higher than a nominal level are detected, where the increased feedback current is an indication that winding inductance has decreased due to a short circuit. Testing at standstill using a small current advantageously prevents the possibility of damaging the motor and avoids inductance variation due to changing rotor position.

Method and apparatus for identifying the winding short of bar wound electric machine at standstill condition

An electric machine assembly includes an electric machine including a rotor. A controller operatively connected to the electric machine and configured to receive a torque command. The rotor is configured to rotate at a rotor speed (&#x3c9;) based at least partially on the torque command. The controller has a processor and tangible, non-transitory memory on which is recorded instructions for executing a method for determining a cumulative rotor fatigue (F) based at least partially on the rotor speed. The controller is operative to control at least one operating paramater of the electric machine based at least partially on the cumulative rotor fatigue (F). The controller is configured to record respective occurrences of the rotor stress value exceeding respective predefined stress levels in chronological order to create a cycle dataset, such that the cycle dataset preserves a time order of the respective occurrences.

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Metamora, MI, United States of America

Chad A Freitas