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:
Aug. 21, 1984
Filed:
Dec. 14, 1981
William P Curtiss, Winthrop, MA (US);
The Charles Stark Draper Laboratory, Inc., Cambridge, MA (US);
Abstract
Sinusoidal excitation currents are supplied to the three terminals of a 'wye' or 'delta' connected three phase motor by an improved multiphase motor energizing drive system. For each terminal associated with a different phase, an individual feedback signal representing the current flowing into that respective terminal is sensed and subtracted from its corresponding controllable sine wave reference command to produce a current error signal for each terminal. The error signal for each of these currents is preferably converted to a two-state signal by means of an associated pulse width modulator. The modulator outputs are used to control power semiconductor switches which connect the corresponding motor terminal to either the positive or negative dc voltage. In the preferred system, for one of the terminals, the associated current feedback loop and reference command are omitted, and the associated pulse width modulator is driven by the inverted sum of the error signals from the other two phases. The result is inherently balanced multiphase excitation currents into the motor terminals.