US 12,334,850 B2
Control systems and methods for mitigating motor start-up instabilities in lightly loaded conditions near synchronous speed
Stan Simms, Arden, NC (US); and Gabriel Teixeira Braga, Belo Horizonte (BR)
Assigned to Eaton Intelligent Power Limited, Dublin (IE)
Filed by Eaton Intelligent Power Limited, Dublin (IE)
Filed on Sep. 5, 2023, as Appl. No. 18/460,869.
Prior Publication US 2025/0080024 A1, Mar. 6, 2025
Int. Cl. G05B 5/00 (2006.01); H02P 23/04 (2006.01); H02P 23/14 (2006.01)
CPC H02P 23/04 (2013.01) [H02P 23/14 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for mitigating phase current oscillations and vibrations in a spinning, lightly loaded three-phase electric motor, wherein the electric motor is configured to receive power from three distinct electrical phases, comprising:
communicating a first command signal to transition to a first acceleration profile, wherein the first acceleration profile is characterized by a first firing angle value and a first rate, wherein transitioning to the first acceleration profile configures a firing angle of a set of thyristors to the first firing angle value and a firing angle rate of change to the first rate, wherein the firing angle corresponds to an angular position of the set of thyristors, wherein each phase of a three-phase power supply to the electric motor is controlled by a pair of thyristors from the set of thyristors, and wherein power supplied to the electric motor is modulated based on the firing angle;
determining an occurrence of a first condition, wherein the occurrence of the first condition indicates that the electric motor had residual motion and was lightly loaded upon transition to the first acceleration profile, wherein the first condition is characterized by an elapse of a predetermined delay period since the transition to the first acceleration profile and an RMS current of the electric motor failing to satisfy a first current threshold;
communicating a second command signal to transition to a second acceleration profile based on the occurrence of the first condition, wherein the second acceleration profile is characterized by a second rate, wherein transitioning to the second acceleration profile configures the firing angle rate of change to the second rate, and wherein the second rate is greater than the first rate;
determining an occurrence of a second condition, wherein the second condition is characterized by the firing angle satisfying a firing angle threshold and the RMS current failing to satisfy a second current threshold; and
communicating a third command signal to transition to a third acceleration profile, wherein the third acceleration profile is characterized by a second firing angle value, wherein transitioning to the third acceleration profile configures the firing angle to the second firing angle value, wherein the second firing angle value corresponds to full operation of the electric motor, wherein transitioning to the third acceleration profile results in application of full voltage on all three distinct electrical phase simultaneously.