Patent ID: 7026776
Filing Date: 2006-04-11
Classification: H02P

Abstract:
1. A method for controlling current in a direct current motor having a back emf constant (k e ) and motor resistance (R s ) comprising the steps of: rotating a motor shaft of the direct current motor with a controller by applying a first voltage across the direct current motor corresponding to a first current value passing through armature windings of the direct current motor; determining a maximum value of current to pass through the armature windings of the direct current motor; receiving a signal corresponding to a desired motor speed (ω) with the controller during said rotating step; first computing a second voltage with the controller to replace the first voltage after said receiving and determining steps and in view of the back emf constant (k limiting the second voltage before replacing the first voltage based at least in part on a difference between the maximum value of current and the first value of current to dynamically control current during said operating step.