US 11,916,507 B2
Motor angular position control
Jian Wu, Houston, TX (US); Ramakrishna Madhireddy, Houston, TX (US); and Nathaniel Wicks, Somerville, MA (US)
Assigned to SCHLUMBERGER TECHNOLOGY CORPORATION, Sugar Land, TX (US)
Filed by Schlumberger Technology Corporation, Sugar Land, TX (US)
Filed on Mar. 3, 2020, as Appl. No. 16/807,918.
Prior Publication US 2021/0277768 A1, Sep. 9, 2021
Int. Cl. H02P 6/08 (2016.01); H02P 6/18 (2016.01); F02D 25/02 (2006.01); E21B 7/06 (2006.01); E21B 3/02 (2006.01)
CPC H02P 6/18 (2013.01) [E21B 7/068 (2013.01); F02D 25/02 (2013.01); E21B 3/022 (2020.05)] 20 Claims
OG exemplary drawing
 
1. A method comprising:
causing operation of a motor controller operable to control rotational speed of an output shaft of an electric motor, wherein:
the motor controller comprises a proportional controller and a time-optimal controller;
the proportional controller controls the rotational speed when a present rotational position of the shaft is between a target rotational position and a switching point, inclusively; and
the time-optimal controller controls the rotational speed when the present rotational position is not between the target rotational position and the switching point,
wherein the switching point is determined via operation of a processor and a memory storing code executable by the processor, and
wherein operation of the processor determines the switching point by:
determining which one of N curves corresponds to a predetermined system communications delay, wherein N is a positive integer, and wherein each of the N curves relates a counter delay factor β to candidate switching points;
determining a smallest one of the candidate switching points that results in a value of the counter delay factor being less than one; and
selecting the switching point as a rotational position that is larger than the determined smallest one of the candidate switching points.