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:
Jun. 21, 1988
Filed:
Jan. 23, 1987
Wolfgang M Radziwill, Aachen, DE;
Gunter Doring, Wurselen, DE;
U.S. Philips Corporation, New York, NY (US);
Abstract
A control circuit for a collectorless d.c. motor, without a commutation sensor, and comprising a stator with a multiphase system and a permanent-magnet rotor. The commutation state of the motor depends on the voltages induced in the stator windings. A comparison signal is generated which indicates whether the sign of that winding voltage which is not connected to a direct current source by means of the circuit electronic switching elements is in conformity with a predetermined sign which depends on the instantaneous commutation state. This comparison signal is inhibited during those time intervals in which transient effects which may cause spurious zero crossings occur in the windings as a result of the electronic switching elements being turned off. The switching elements are always switched one commutation step further if the comparison signal does not have the appropriate sign.