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:
Apr. 28, 2009
Filed:
Apr. 13, 2007
Marco Viti, Cornaredo, IT;
Marco Viti, Cornaredo, IT;
STMicroelectronics S.r.l., Agrate Brianza, IT;
Abstract
A control device controls an electric motor that includes a winding and generates a back electromotive force. The device comprises a first circuit suitable for setting time periods each centered on the time instant of an expected zero crossing of the winding current and a second circuit suitable for generating a signal representing the polarity in the winding in the time periods. The first and second circuits are suitable for providing samples of the polarity signal. The control device comprises a counting circuit suitable for counting the samples of the polarity signal and a further circuit receiving the count and being suitable for deducing the distance between the time instant of the expected zero crossing and the actual zero crossing instant; the further means is suitable for determining the phase shift between the driving voltage of the electric motor and the induced back electromotive force based on the distance.