Patent ID: 9046544
Filing Date: 2015-06-02
Classification: G01P,Y10S

Abstract:
1. A system for determining motor speed of a brush DC motor in an apparatus, comprising: sensing circuitry for sensing current in the brush DC motor; a first filter for receiving a substantially low frequency portion of the sensed current and parameters corresponding to the brush DC motor, for calculating a speed estimate thereof; an adaptive bandpass filter having a center frequency corresponding to the speed estimate of the first filter, for receiving the sensed current and substantially isolating a first periodic current fluctuation thereof; a frequency detect block for determining a frequency of the first periodic current fluctuation, a frequency of the first periodic current fluctuation corresponding to motor speed of the brush DC motor; and a tracking frequency selection block coupled to the sensing circuitry for selecting a frequency component of the sensed current and providing the selected frequency component to the first filter, wherein the speed estimate is based in part upon the selected frequency component.