Systems and methods for controlling contactor open time

Patent metadata

Field	Value
Publication number	US-11676786-B2
Application number	US-202016844101-A
Country	US
Kind code	B2
Filing date	Apr 9, 2020
Priority date	Apr 9, 2020
Publication date	Jun 13, 2023
Grant date	Jun 13, 2023

Abstract

A device includes an armature, a coil, and a circuit. The armature is configured to move between a close position that electrically couples the armature to a contact and an open position that is not electrically coupled to the contact. The coil is configured to release a voltage configured to de-magnetize the coil, thereby causing the armature to move from the close position to the open position. The circuit is configured to provide reverse driving current to the coil during a period of time when the armature moves from the close position to the open position.

First claim

What is claimed is:

1. A device, comprising:
an armature configured to move between a close position that electrically couples the armature to a contact and an open position that is not electrically coupled to the contact;
a coil configured to release a voltage to de-magnetize the coil, thereby causing the armature to move from the close position to the open position; and
a circuit configured to provide a forward driving current to the coil to magnetize the coil, thereby causing the armature to move from the open position to the close position, and to provide a reverse driving current to the coil during a period of time when the armature moves from the close position to the open position when the coil generates a back electromotive force in response to a loss of the forward driving current, wherein the circuit provides the reverse driving current concurrently with the coil generating the back electromotive force whereby the reverse driving current absorbs the back electromotive force.

2. The device of claim 1 , further comprising:
a first power source configured to provide the forward driving current to the coil; and
a second power source configured to provide the reverse driving current to the coil.

3. The device of claim 1 , wherein the circuit comprises a first switch and a second switch configured to be turned on to enable the forward driving current to flow through the coil and to be turned off to disable the forward driving current flowing through the coil.

4. The device of claim 3 , wherein the circuit comprises a third switch and a fourth switch configured to be turned on to enable the reverse driving current to flow through the coil and be turned off to disable the reverse driving current flowing through the coil.

5. The device of claim 4 , wherein the first switch and the third switch are connected to a first end of the coil and the second switch and the fourth switch are connected to a second end of the coil.

6. The device of claim 1 , wherein the circuit includes a Zener diode, a resistor, and a capacitor, wherein the Zener diode and the capacitor are arranged in parallel with the resistor.

7. A circuit configured to provide a reverse coil drive current for a switching system, comprising:
a coil;
a first power source connected to a second end of the coil;
a first switch connected to a first end of the coil; and
a second switch connected to the second end of the coil, wherein when the first switch and the second switch are turned on, a current from the first power source is enabled to flow through the coil from the second end to the first end to provide a forward driving current to the coil to magnetize the coil when the switching system moves from an open state to a closed state,
wherein when the first switch and the second switch are turned off, the circuit is configured to provide a reverse driving current to the coil during a period of time when the switching system moves from the closed state to the open state when the coil generates a back electromotive force in response to a loss of the forward driving current, wherein the circuit provides the reverse driving current concurrently with the coil generating the back electromotive force whereby the reverse driving current absorbs the back electromotive force.

8. The circuit of claim 7 , further comprising a second power source connected to the first end of the coil.

9. The circuit of claim 8 , wherein the first power source and the second power source are different power sources.

10. The circuit of claim 8 , wherein the first power source and the second power source are a same power source.

11. The circuit of claim 8 , further comprising:
a third switch connected to the first end of the coil; and
a fourth switch connected to the second end of the coil, wherein when the third switch and the fourth switch are turned on, a current from the second power source is enabled to flow through the coil from the first end to the second end, wherein when the third switch and the fourth switch are turned off, the current from the second power source is disabled from flowing through the coil from the first end to the second end.

12. The circuit of claim 11 , wherein the first and the second switches are turned on after the third and the fourth switches are turned off so that core flux of the coil is eliminated.

13. The circuit of claim 7 , wherein the first power source comprises a capacitor.

14. The circuit of claim 13 , wherein the first and the second switches are turned off when the capacitor is sufficiently discharged.

15. A method of driving a coil of a switching system, comprising:
enabling, by a circuit, a current flowing through the coil in a forward direction to magnetize the coil thereby changing the switching system from an open state to a closed state;
disabling, by the circuit, the current flowing through the coil in the forward direction; and
enabling, by the circuit, a current flowing through the coil in a reverse direction during a period of time when the switching system moves from the closed state to the open state when the coil generates a back electromotive force in response to a loss of the current flowing through the coil in the forward direction, to eliminate core flux of the coil, wherein the current flowing through the coil in the reverse direction occurs concurrently with the coil generating the back electromotive force whereby the current flowing through the coil in the reverse direction absorbs the back electromotive force.

16. The method of claim 15 , further comprising:
determining whether the switching system reaches a steady closed state; and
upon determining that the switching system reaches the steady closed state, disabling, by the circuit, the current flowing through the coil in the forward direction.

17. The method of claim 15 , wherein enabling and disabling the current flowing through the coil in the reverse direction comprises turning on and off a first and a second switches connected to the coil in different ends.

18. The method of claim 15 , enabling and disabling the current flowing through the coil in the forward direction comprises turning on and off a third and a fourth switches connected to the coil in different ends.

19. The device of claim 4 , wherein a control system is connected to the circuit and configured to:
turn on the first and the second switches and turn off the third and the fourth switches to enable the forward driving current through the coil;
determine whether the armature is turned to the close position and reaches a steady state; and
upon determining that the armature is in the close position and reaches the steady state, turn off the first and the second switches to disable the forward driving current.

20. The device of claim 19 , wherein the control system is further configured to:
turn on the third and the fourth switches for the period of time after the first and the second switches being turned off to enable the reverse driving current to flow through the coil, wherein the period of time is determined so that core flux in the coil is eliminated; and
turn off the third and the fourth switches to disable the reverse driving current flowing through the coil.

Assignees

• Rockwell Automation Tech Inc

Inventors

• Carlson Andrew E
• Adkins Kyle B
• Messersmith David M

Classifications

• H01H50/643

  intermediate part performing a rotating or pivoting movement (H01H50/645, H01H50/66 - H01H50/74 take precedence) · CPC title

• H01H47/22

  for supplying energising current for relay coil · CPC title

• H02H1/06 Primary

  Arrangements for supplying operative power {(power supply arrangements in general G05F, H02M)} · CPC title

• H01H47/325

  by switching regulator · CPC title

• H01H9/56 Primary

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