Patent ID: 7184927

Claim:
An adaptive, indirect position sensing apparatus for deriving rotor position of a synchronous machine, said apparatus comprising: a first rotor position deriving unit for generating first rotor position values by applying a first indirect rotor position calculation technique, which emulates a resolver, wherein said first indirect rotor position calculation technique generates first rotor position values by filtering an output of said synchronous machine based on a frequency component of excitation supplied to a field winding of the synchronous machine rotor, said synchronous machine also including a main stator coil that receives multi-phase AC power, which is separate from said AC excitation supplied to said field winding, to drive movement of said rotor; a second rotor position deriving unit for generating second rotor position values by applying a second indirect rotor position calculation technique; and a rotor position result output unit for outputting rotor position results over a range of rotor speeds as a function of said first rotor position values, said second rotor position values, and rotor speed.