Browse Prior Art Database

PULSE POSITION CONTROL OF BRUSHLESS D. C. MOTORS

IP.com Disclosure Number: IPCOM000023276D
Original Publication Date: 1977-Apr-30
Included in the Prior Art Database: 2004-Mar-29

Publishing Venue

Xerox Disclosure Journal

Abstract

A phase locked loop-motor control system which may find part-icular application in facsimile devices operating on a digital data input pulse train (A) . The torque on the motor which controls, for example, the photoreceptor rotational speed in xerographic machines, is regulated by controlling the phase angle of the power pulses (B) to the motor windings, relative to the shaft position, via power amplifier and commutation means 14. This is accomplished by means of a power pulse position modulation circuit having a comparator 10 which com-pares the phase of the power pulses (B) and the data input pulses (A) . The output (C) of the comparator 10 is utilized as a shift control pulse in the holding circuit 12. Holding circuit 12 operates on a shaft position feedback pulse train (D) derived from an encoder (not shown) coupled to the motor output shaft. The holding circuit will delay or advance the power pulses (8) , relative to the feedback pulses (D) , ac-cording to the width of the shift pulses (C) . In such manner, the frequency of the shaft position pulses (D) and therefore, shaft speed will be automatically adjusted to the same fre-quency as the data input pulses (A)