05017845 is referenced by 65 patents and cites 5 patents.

A starting and operating apparatus and method for a sensorless, brushless direct current motor is disclosed. During start-up, the excitation to the motor is turned off while the slope of the differential back electromotive force of the floating phases is sampled. This indicates when the proper rotation and torque of the motor is obtained. After starting the motor, the apparatus samples the slope of the back electromotive force of the floating coils and finds a zero or predetermined slope condition which has been found to be near the optimum switching point for commutation from one phase to the next. A masking circuit is included to prevent an unwanted commutation immediately after commutating to the next phase.

Title
Brushless direct current motor starting and operating apparatus and method
Application Number
7/593002
Publication Number
5017845
Application Date
October 5, 1990
Publication Date
May 21, 1991
Inventor
Mark McCormack
Phoenix
AZ, US
Ermanno Pace
Phoenix
AZ, US
Francesco Carobolante
Phoenix
AZ, US
Agent
Richard K Robinson
Ronald S Lombard
Assignee
SGS Thomson Microelectronics
TX, US
IPC
H02P 6/02
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