Patent ID: 11872893
Assignee: SEOUL NATHIONAL UNIVERSITY
Field: Transport (Mechanical engineering)
Classification: CPC B  H | IPC B  H

Claim 9:
10. A method of operating a propulsion system in a device, the propulsion system having an electric motor with a stator, a rotor, a position sensor, and a controller having a processor and tangible, non-transitory memory, the method comprising:
determining if a sensor fault condition in the position sensor has been detected;
determining a motor speed of the electric motor;
commanding injection of a voltage signal in a direct magnetic axis of a synchronous reference frame, when the motor speed is below a predefined motor speed threshold and the sensor fault condition is detected;
selecting the voltage signal to have an alternating periodic shape with respective constant segments in each of a plurality of control periods, the respective constant segments being discontinuous between the plurality of control periods; and
estimating the rotor position based in part on a motor current response to the voltage signal.