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

Claim 0:
1. 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 in the position sensor 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 respective constant segments being discontinuous between the plurality of control periods.