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. 21, 1998
Filed:
Dec. 06, 1996
Josephus A Kahlman, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
The drive system (210) comprises an electronically commutated motor (220) having three windings (225, 226 and 227). The motor (220) is energized by an energizing circuit (270). The energizing means (270) is controlled by three Hall elements (241, 242 and 243) which supply sensor signals (H.sub.1, H.sub.2 and H.sub.3). The motor comprises a permanent-magnetic part whose position is measured by means of the Hall elements. The drive system (210) comprises a status generator (280) which generates status signals (Q.sub.1, Q.sub.2, Q.sub.3 and Q.sub.4) which are dependent upon the ratio between the actual values of the sensor signals (H.sub.1, H.sub.2 and H.sub.3). The drive system (210) further comprises a multiplexer (290) and an inverter (295) which are controlled by the status signals (Q.sub.1, and Q.sub.2, respectively) in order to generate a position signal (P). A corrected position signal (P') is applied to a comparator (260) to generate an error signal (E). By means of this comparator (260) the corrected position signal (P') is compared with a reference value (R) generated by the sawtooth generator (250). The sawtooth generator (250) comprises a digital counter which indicates the reference value (R) and which is decremented by a step size (dR) at a step frequency (f). The output of the comparator (260) is connected to the energizing circuit (270) via a loop filter (295). The reference value (R) is adapted to transients in the position signal. For this purpose, the drive system (210) includes a multiplier (205) and a switch (206). A transient occurs when the multiplexer (290) or the switch (296) is switched over.