Control of motor soft starter using power electronic switching devices

Patent metadata

Field	Value
Publication number	US-12519404-B2
Application number	US-202218276740-A
Country	US
Kind code	B2
Filing date	Feb 10, 2022
Priority date	Feb 10, 2021
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

Systems and methods for soft starting a motor ( 40 ) using solid-state switching devices are disclosed. The system ( 10 ) includes a soft starting switch ( 53 ) that is made of a plurality of solid-state switches ( 62, 63 ). The system ( 10 ) also includes a controller ( 86 ) that is programmed to regulate currents and voltages delivered to the motor ( 40 ) during a start-up operation of the motor by cycling the solid-state switches ( 62, 63 ) ON and OFF during the start-up operation.

First claim

What is claimed is:

1 . A method of soft starting a motor, the method comprising:
providing a soft starting switch that is electrically connected between a power source and an alternating current (AC) motor, wherein: the soft starting switch comprises one or more phases, each of which comprises:
a power electronic switching device that comprises a plurality of solid-state switches electrically connected in series or in parallel with each other; and
by a controller, cycling the solid-state switches ON and OFF during a start-up operation to regulate currents and voltages delivered to the AC motor during the start-up operation, wherein cycling the solid-state switches ON and OFF during the start-up operation comprises, by the controller: receiving current data from one or more current sensors, and detecting a plurality of Current zero crossings in the current data over a plurality of current cycles; receiving voltage data from one or more sensors, and detecting a plurality of current zero crossings in the voltage data over a plurality of voltage cycles; and for each phase:
determining a firing angle for a present voltage cycle,
using the detected voltage zero-crossings and the firing angle for the present voltage cycle to determine a time to command that phase's solid-state switches to gate ON, and
using the detected current zero-crossings info and a current zero-crossing detection tolerance threshold to determine a time to command that phase's solid-state switches to gate OFF.

2 . The method of claim 1 further comprising, by the controller in each phase upon completion of the start-up operation, transitioning the soft starting switch from the start-up operation to a run mode by commanding the solid-state switches to remain ON.

3 . The method of claim 1 , wherein the soft starting switch further comprises a mechanical switch that is electrically connected in parallel with the power electronic switching device.

4 . The method of claim 3 further comprising, by the controller in each phase upon completion of the start-up operation, transitioning the soft starting switch from the start-up operation to a run mode by:
causing an actuator to close the mechanical switch; and
either:
commanding the solid-state switches to remain ON to create a short circuit condition, or
commanding the solid-state switches to turn OFF and remain OFF to create a bypass condition.

5 . The method of claim 1 , wherein determining the firing angle comprises accessing motor profile data for the motor and identifying, from the motor profile, a firing angle that corresponds to a present time in the start-up operation.

6 . A system for soft starting a motor, the system comprising:
a soft starting switch comprising:
a line side for connecting to a power source and a load side for connecting to a motor, and
a power electronic switching device that is positioned between the line side and the load side, and that comprises a plurality of solid-state switches electrically connected in series or in parallel with each other;
a controller configured to regulate currents and voltages delivered to the motor during a start-up operation of the motor by cycling the solid-state switches ON and OFF during the start-up operation; one or more current sensors; one or more voltage sensors; and programming instructions that are configured to cause the controller to:
receive current data from the one or more current sensors,
detect a plurality of current zero crossings in the current data over a plurality of current cycles,
receive voltage data from the one or more voltage sensors,
defect a plurality of voltage zero crossings in the voltage data over a plurality of voltage cycles, and
for each phase:
determine a firing angle for a present voltage cycle;
use the detected voltage zero-crossings and the firing angle for the present voltage cycle to determine a time to command that phase's solid-state switches to gate ON; and
use the detected current zero-crossings information and a current zero-crossing detection tolerance threshold to determine times to command that phase's solid-state switches to gate OFF.

7 . The system of claim 6 , wherein each of the plurality of solid-state switches comprises:
a metal oxide field effect transistor (MOSFET); a gallium nitride (GaN)-on-silicon power field effect transistor; a junction field effect transistor (JFET); a MOS-controlled thyristor (MCT); or another silicon carbide (SiC)-based or GaN-based or other semiconductor material-based actively switchable power semiconductor device.

8 . The system of claim 6 , wherein each of the plurality of solid-state switches comprises an insulated gate bipolar transistor (IGBT) or another silicon (Si)-based switching device.

9 . The system of claim 6 , wherein the soft starting switch further comprises a mechanical switch that is electrically connected in parallel with the power electronic switching device.

10 . The system of claim 6 , wherein the controller comprises a memory containing motor profile data for the motor, and wherein the motor profile comprises:
firing angle data that maps firing angle values for the motor to points in time over the start-up operation; and the current zero-crossing detection tolerance threshold.

11 . The system of claim 10 , wherein the power electronic switching device further comprises a plurality of varistors, each of which is electrically connected in parallel across one or more of the solid state switches.

Assignees

• Eaton Intelligent Power Ltd

Inventors

• Li Jin
• Zhou Xin
• Dimino Steven A
• Woodley Kaijam Maurice

Classifications

• H01H2009/543

  third parallel branch comprising an energy absorber, e.g. MOV, PTC, Zener · CPC title

• H01H9/56

  for ensuring operation of the switch at a predetermined point in the AC cycle · CPC title

• H02H7/0833

  for electric motors with control arrangements · CPC title

• H02H1/043

  to inrush currents (H02H1/046 takes precedence; differential protection of transformers H02H7/045) · CPC title

• H02P6/28

  Arrangements for controlling current (H02P6/10 takes precedence) · CPC title