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:
Feb. 08, 2000
Filed:
Nov. 28, 1997
Peter J Pinewski, Chandler, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An electric motor (101) is driven with a sequence of drive pulses (V.sub.151, V.sub.153, V.sub.155) applied to its coils (131-135). The drive pulse widths are computed over a series of time periods (T.sub.DRIVE) by a pulse generator (119) to form envelopes approximating the phase voltages (VE.sub.151, VE.sub.153, VE.sub.155) of the coils to produce sinusoidal coil currents (I.sub.131, I.sub.133, I.sub.135). A sensing circuit (137, 123) monitors the phase of the coil current with respect to phase voltage to compute a representative control signal (CONTROL). The phase has one polarity when the motor is delivering power from a battery to a load and the opposite polarity when power is delivered from the load to the battery. When the direction of transferred power changes, the control signal changes and the pulse generator switches on-the-fly to another sequence of drive pulses.