Soft start motor control system for an irrigation system

Patent metadata

Field	Value
Publication number	US-10517286-B2
Application number	US-201715684423-A
Country	US
Kind code	B2
Filing date	Aug 23, 2017
Priority date	Aug 23, 2017
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

Abstract

An irrigation system broadly comprising a number of irrigation spans and a control system configured to operate single speed drive motors of the irrigation spans in a start-up mode, full speed mode, and wind-down mode. In the start-up mode, the motor controller gradually increases the drive motor speed from 0 rpms to a full speed by ramping a voltage applied to the drive motor from a starting voltage to a full speed voltage according to a start-up voltage profile over a start-up time interval. In the full speed mode, the motor controller operates the drive motor at a full speed voltage. In the wind-down mode, the motor controller gradually decreases the drive motor speed from full speed to 0 rpms by ramping the voltage applied to the drive motor from the full speed voltage to an ending voltage according to a wind-down voltage profile over a wind-down time interval.

First claim

Having thus described one or more embodiments of the invention, what is claimed as new and desired to be protected by Letters Patent includes the following:

1. An irrigation system comprising:
a plurality of irrigation spans, each including:
a conduit section connected to conduit sections of adjacent irrigation spans for transporting an irrigation fluid from a fluid source to a field;
a truss configured to support the conduit section;
a plurality of fluid emitters connected to the conduit section for delivering the irrigation fluid to crops in the field; and
a mobile tower connected to the truss and configured to move the truss, conduit section, and fluid emitters across the field, the mobile tower including:
a wheel assembly for traversing the field; and
a drive train having a single-speed motor for powering the wheel assembly; and

a control system for controlling the single-speed motors of the drive trains, the control system configured to operate at least one of the single-speed motors in:
a start-up mode in which the control system gradually increases a speed of the single-speed motor from 0 rpms to a full speed;
a full speed mode; and
a wind-down mode in which the control system gradually decreases the speed of the single-speed motor from the full speed to 0 rpms.

2. The irrigation system of claim 1 , wherein the control system is configured to operate at least one of the single-speed motors only in the full speed mode.

3. The irrigation system of claim 1 , wherein the irrigation system is a center-pivot irrigation system further comprising a center pivot, the irrigation spans including at least four irrigation spans extending end-to-end from the center pivot, the control system being configured to operate the single-speed motors of at least the two outermost irrigation spans in the start-up mode, full speed mode, and wind-down mode and the single-speed motors of at least the two innermost irrigation spans only in the full speed mode.

4. The irrigation system of claim 1 , wherein the control system is configured to operate every other single-speed motor in the start-up mode, full speed mode, and wind-down mode.

5. The irrigation system of claim 1 , wherein the control system initiates the start-up mode at a pre-set starting voltage less than a full speed voltage.

6. The irrigation system of claim 5 , wherein the control system actively ramps applied voltage in the start-up mode from the starting voltage to the full speed voltage.

7. The irrigation system of claim 6 , wherein the control system ramps applied voltage in the start-up mode from the pre-set starting voltage to the full speed voltage according to a pre-determined voltage profile.

8. The irrigation system of claim 1 , wherein each irrigation span includes an alignment sensor and the control system initiates the start-up mode for the single-speed motor of one of the irrigation spans upon receiving an alignment signal from the alignment sensor of the irrigation span indicating that the irrigation span is misaligned.

9. The irrigation system of claim 1 , wherein the control system operates the single-speed motors in the start-up mode for a pre-set amount of time.

10. The irrigation system of claim 1 , wherein the control system initiates the start-up mode at a non-zero torque.

11. The irrigation system of claim 1 , wherein a parameter of the start-up mode is at least partially determined according to at least one of a motor size, a motor speed rating, and a tire size of the wheel assembly.

12. The irrigation system of claim 1 , wherein the control system terminates the wind-down mode at a pre-set ending voltage less than the full speed voltage.

13. The irrigation system of claim 12 , wherein the control system actively ramps applied voltage in the wind-down mode from the full speed voltage to the ending voltage.

14. The irrigation system of claim 13 , wherein the control system ramps applied voltage from the full speed voltage to the pre-set ending voltage according to a pre-determined voltage profile.

15. The irrigation system of claim 1 , wherein the control system includes an alignment sensor mounted on each irrigation span and the control system initiates the wind-down mode for the single-speed motor of one of the irrigation spans upon receiving an alignment signal from the alignment sensor on the irrigation span indicating that the irrigation span has become aligned or is nearing alignment.

16. The irrigation system of claim 1 , wherein the control system operates the single-speed motors in the wind-down mode for a pre-set amount of time.

17. The irrigation system of claim 1 , wherein the control system terminates the wind-down mode at a non-zero torque.

18. The irrigation system of claim 1 , wherein a parameter of the wind-down mode is at least partially determined according to at least one of a motor size, a motor speed rating, and a tire size of the wheel assembly.

19. The irrigation system of claim 1 , wherein the single-speed motors are single-speed induction motors.

20. The irrigation system of claim 1 , wherein the control system includes a plurality of controllers, each controller being mounted on one of the mobile towers for controlling one of the single-speed motors.

21. A center-pivot irrigation system comprising:
a center pivot;
at least four irrigation spans extending end-to-end from the center pivot, each irrigation span including:
a conduit section connected to conduit sections of adjacent irrigation spans for transporting an irrigation fluid from a fluid source to a field;
a truss configured to support the conduit section;
a plurality of fluid emitters connected to the conduit section for delivering the irrigation fluid to crops in the field; and
a mobile tower connected to the truss and configured to move the truss, conduit section, and fluid emitters across the field, the mobile tower including:
a wheel assembly for traversing the field; and
a drive train having a single-speed motor for powering the wheel assembly; and

a control system for controlling the single-speed motors of the drive trains, the control system configured to operate the single-speed motors of at least the outer two irrigation spans in:
a start-up mode in which the control system gradually ramps a voltage applied to the single-speed motor from a pre-set starting voltage to a full speed voltage over a pre-set start-up time duration according to a linear voltage profile so as to gradually increase a speed of the single-speed motor from 0 rpms to a full speed;
a full speed mode; and
a wind-down mode in which the control system gradually ramps the voltage applied to the single-speed motor from the full speed voltage to a pre-set ending voltage over a pre-set wind-down time duration according to a linear voltage profile so as to gradually decrease the speed of the single-speed motor from the full speed to 0 rpms,
at least one parameter of the start-up mode and at least one parameter of the wind-down mode being at least partially determined according to at least one of a motor size, a motor speed rating, and a tire size of the wheel assemblies.

Assignees

• Lindsay Corp

Inventors

• Miller Mark William
• Ellison Bradford

Classifications

• B05B12/082

  responsive to a condition of the discharged jet or spray, e.g. to jet shape, spray pattern or droplet size · CPC title

• B05B13/005

  mounted on vehicles or designed to apply a liquid on a very large surface, e.g. on the road, on the surface of large containers · CPC title

• H02P2207/01

  Asynchronous machines · CPC title

• B05B13/04

  the spray heads being moved during {spraying} operation · CPC title

• A01C23/042

  Adding fertiliser to watering systems · CPC title