US 11,689,125 B2
Encoderless motor with improved granularity and methods of use
Tien Phan, Sunnyvale, CA (US); and Doug Dority, Sunnyvale, CA (US)
Assigned to Cepheid, Sunnyvale, CA (US)
Filed by Cepheid, Sunnyvale, CA (US)
Filed on Mar. 30, 2021, as Appl. No. 17/217,926.
Application 17/217,926 is a continuation of application No. 16/375,044, filed on Apr. 4, 2019, granted, now 10,972,025.
Application 16/375,044 is a continuation of application No. 15/217,893, filed on Jul. 22, 2016, granted, now 10,348,225, issued on Jul. 19, 2019.
Claims priority of provisional application 62/195,449, filed on Jul. 22, 2015.
Prior Publication US 2021/0351727 A1, Nov. 11, 2021
Int. Cl. H02K 11/215 (2016.01); H02K 1/27 (2022.01); H02K 11/00 (2016.01); H02K 15/02 (2006.01); H02P 6/16 (2016.01); H02K 29/08 (2006.01); H02K 21/22 (2006.01); H02K 1/2786 (2022.01)
CPC H02P 6/16 (2013.01) [H02K 1/27 (2013.01); H02K 11/0094 (2013.01); H02K 11/215 (2016.01); H02K 15/02 (2013.01); H02K 29/08 (2013.01); H02K 1/2786 (2013.01); H02K 21/22 (2013.01); H02K 2211/03 (2013.01); H02K 2213/03 (2013.01)] 26 Claims
OG exemplary drawing
 
1. A DC electric motor comprising:
a stator mounted to a substrate, the stator comprising a coil assembly having a core of magnetic material and electrical windings, the coil assembly having an outside diameter, a proximal extremity, and a distal extremity;
a rotor mounted to the stator, the rotor comprising permanent magnets mounted to a cylindrical skirt, each magnet extending to a distal edge thereof, the rotor having an outside diameter, an inside diameter, wherein the distal edges of the permanent magnets extend beyond the core of magnetic material in a vertical direction when the rotor is oriented horizontally;
a plurality of sensors mounted on a surface of the substrate adjacent the permanent magnets, the surface facing the permanent magnets such that during operation of the motor, passage of the permanent magnets over the plurality of sensors produces a plurality of sinusoidal signals of varying voltage;
wherein a clearance between the extended distal edge of each of the permanent magnets and the plurality of sensors is defined so as to avoid noise and saturation in each signal of the plurality of signals; and
a processor module communicatively coupled with the plurality of sensors and configured to:
receive the plurality of voltage signals from the plurality of sensors during rotation of the rotor, each signal being a sinusoidal signal having a linear portion; and
determine a displacement of the motor from the plurality of sinusoidal signals including the linear portions without use of a hardware encoder, and without any noise-reduction or filtering of the voltage signals.