Patent ID: 11872893
Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
Field: Transport (Mechanical engineering)
Classification: CPC B  H | IPC B  H

Claim 18:
19. A propulsion system for a device, comprising:
an electric motor configured to generate torque to propel the device, the electric motor including a stator and a rotor;
a position sensor adapted to determine a rotor position of the electric motor;
a controller having a processor and tangible, non-transitory memory on which instructions are recorded for determining the rotor position when a sensor fault condition is detected;
wherein the controller is adapted to:
determine a motor speed of the electric motor;
selectively command injection of a voltage signal in a direct magnetic axis in a synchronous reference frame when the motor speed is below a predefined motor speed threshold and the sensor fault condition is detected; and
estimate the rotor position based in part on a motor current response to the voltage signal;

wherein the voltage signal is defined by an alternating periodic shape with respective constant segments in each of a plurality of control periods, the voltage signal having a zero-magnitude signal in a quadrature magnetic axis in the synchronous reference frame; and
wherein the alternating periodic shape has a partially sinusoidal shape, the respective constant segments being discontinuous between the plurality of control periods.