Position sensing method and apparatus for synchronous motor generator system

摘要

A position sensing apparatus ( 300 ) derives rotor position of a synchronous machine ( 200 ) from signals output from the machine ( 200 ). In one embodiment, the position sensing apparatus ( 300 ) comprises: a bandpass filter ( 322 ) that filters phase voltage signals output from main stator windings ( 216 ) of the synchronous machine ( 200 ) during AC excitation, thereby extracting a rotor position-indicating component from the phase voltage signals; a converter ( 324 ) that converts the filtered phase voltages into balanced two-phase quadrature signals, the balanced two-phase quadrature signals indicating positioning of the rotor ( 212 ); and an excitation controller ( 204 ) for controlling AC excitation frequency as a function of rotor speed.