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Method and apparatus for sensorless operation of brushless permanent magnet motors

United States Patent

*** EXPIRED ***
April 14, 1998
View the Complete Patent at the US Patent & Trademark Office
National Renewable Energy Laboratory - Visit the NREL Technology Transfer Website
A sensorless method and apparatus for providing commutation timing signals for a brushless permanent magnet motor extracts the third harmonic back-emf of a three-phase stator winding and independently cyclically integrates the positive and negative half-cycles thereof and compares the results to a reference level associated with a desired commutation angle.
Sriram; Tillasthanam V. (Carmel, IN)
General Motors Corporation (Detroit, MI)
08/ 770,862
December 20, 1996
The Government of the United States has rights in this invention pursuant to Subcontract ZCB-3-13032 under Prime Contract No. DE-AC36-83CH10093 awarded by the U.S. Department of Energy.