04928043 is referenced by 119 patents and cites 7 patents.

A sensorless control for DC permanent magnet brushless motor includes a feedback loop connected between the motor stator windings and the inverter which controls the timer at which current is provided to the various windings in sequence. The control of the invention includes a voltage sensing network for sensing the back EMF on each motor winding when it is unenergized and comparing this voltage with a null point. For maximum torque this voltage has an optimum value and variation from this value produces an error signal which is integrated to produce a VCO drive signal. This signal controls the frequency of a VCO which in turn controls the switching times of the inverter.

Title
Back EMF sampling circuit for phase locked loop motor control
Application Number
7/270611
Publication Number
4928043
Application Date
November 14, 1988
Publication Date
May 22, 1990
Inventor
Allan B Plunkett
Portland
OR, US
Agent
Chernoff Vilhauer McClung & Stenzel
Assignee
Synektron Corporation
OR, US
IPC
H02R 6/02
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