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. 11, 2006
Filed:
Jun. 30, 2005
James E. Walters, Carmel, IN (US);
James E. Walters, Carmel, IN (US);
Delphi Technologies, Inc., Troy, MI (US);
Abstract
The invention provides a method for controlling current in a direct current motor having a back emf constant (k), which may be a function of field current if the direct current motor is a field wound machine, and motor resistance (R) in all 4 quadrants of operation. The method includes the step of rotating a motor shaft of the direct current motor with a controller by applying a first voltage across the direct current motor's terminals. The first voltage corresponds to a first value of current passing through the armature windings of the direct current motor. The method also includes the step of determining a maximum value of current to pass through the armature windings of the direct current motor. The maximum value of current is selected to prevent undesirable over current conditions, such as thermal overload as one example. The method also includes the step of receiving a signal corresponding to a desired motor speed (ω*) with the controller during the rotating step. The method also includes the step of first computing a second voltage to replace the first voltage from the controller after the receiving and determining steps and in view of the estimates of the back emf constant (k) and the armature resistance (R) of the direct current motor. The method also includes the step of limiting the second voltage, if necessary to limit the current, before replacing the first voltage based at least in part on a difference between the maximum value of current and the current polarity, a gain quantity, and the first value of current and voltage in order to dynamically control current during the operating step.