Implicit rotor-position sensing using motor windings for a self-commutating permanent-magnet drive system

摘要

The authors describe a novel method of rotor-position sensing of permanent-magnet machines, which requires no encoder nor any modification to conventional machines. The machine is electronically commutated, by virtue of position sensing, achieved through measuring the modulation in the inverter carrier frequency component, caused by the positional variation in motor winding impedance. A closed-loop speed control system drives the motor with precision and at maximum efficiency for a wide range of load and speed.