Additional high-frequency signal for sensorless angular positioning of the rotor in synchronous motors

This is a feasibility test for sensorless angular rotor positioning. The paper analyzes the existing methods for sensorless control of angular rotor position in AC motors. It identifies their common drawbacks, one of which is that angular rotor position is difficult to determine at low or zero rotor speed unless a mechanical sensor is in use. The paper presents the functional diagram of a sensorless electric drive based on a synchronous motor. It considers the correlation of induced EMF and high-frequency voltage signal fed to the SM excitation winding. The paper further derives a formula to describe the angular rotor position as a function of phase EMF. The derivation is based on Park-Gorev equations. The obtained dependencies are used in an implemented structural diagram, with the research output being discussed in detail.