The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 07, 1987
Filed:
Oct. 07, 1986
James O Elliott, Beavercreek, OH (US);
Michael B Monahan, West Carrolton, OH (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A sensorless control system for reliably starting a brushless DC motor even when the motor/load inertia is relatively high and even though the rotor may be rotating in the wrong direction when starting is initiated. The line-to-line generated voltages of two deenergized stator windings are compared as a given stator winding is energized. The energization is either interrupted or permitting to continue depending on the comparison. If the comparison indicates that the rotor is turning in the correct direction, the energization is continued to produce synchronous positive torque for accelerating the rotor in that direction. If the generated voltage comparison indicates that the rotor is turning in the wrong direction, the winding energization is interrupted, and the next sequential winding is energized. The interruption occurs in alternate windings of the energization sequence, effectively reversing the energization sequence to generate substantially maximum synchronous braking torque for bringing the rotor substantially to a stop, whereafter starting may be attempted again.