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1. (WO1999009644) METHOD AND APPARATUS FOR DRIVING A BRUSHLESS DC MOTOR WITHOUT ROTOR POSITION SENSORS

Pub. No.:    WO/1999/009644    International Application No.:    PCT/US1998/016917
Publication Date: Fri Feb 26 00:59:59 CET 1999 International Filing Date: Sat Aug 15 01:59:59 CEST 1998
IPC: H02P 6/14
H02P 6/18
Applicants: ALLIEDSIGNAL INC.
Inventors: KALMAN, Gabor, P.
Title: METHOD AND APPARATUS FOR DRIVING A BRUSHLESS DC MOTOR WITHOUT ROTOR POSITION SENSORS
Abstract:
In a brushless dc motor, commutation is performed without the use of rotor position sensors. A voltage across a non-conducting winding of the motor is measured, a voltage across a conducting winding of the motor is computed, an emf Park vector is computed from the voltages, an imaginary component of a rotated emf Park vector is extracted, and the imaginary component is processed to determine when to perform the commutation from one winding to the next sequential winding.