Systems and methods for controlling relays

Patent metadata

Field	Value
Publication number	US-10170257-B2
Application number	US-201314759803-A
Country	US
Kind code	B2
Filing date	Jan 10, 2013
Priority date	Jan 10, 2013
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

Abstract

A relay control circuit for use with a relay having a coil voltage input. The relay control circuit includes a first input to receive a first voltage capable of energizing the relay, a second input to receive a second voltage, less than the first voltage, that is capable of maintaining the relay in an energized state, and means, responsive to a relay control signal having one of a first state and a second state, for switchably coupling the coil voltage input to the first input in response to the relay control signal having the first state, and for switchably coupling the coil voltage input to the second input in response to the relay control signal having the second state.

First claim

What is claimed is:

1. A relay control circuit configured for use with a relay having a coil voltage input, the relay control circuit comprising:
a first input to receive a first voltage capable of energizing the relay from a de-energized state;
a second input to receive a second voltage capable of maintaining the relay in an energized state, the second voltage being less than the first voltage;
a switch disposed between the first input and the coil voltage input, the switch having a control input to receive a control signal that electrically couples the first input to the coil voltage input in response to the control signal having a first state and that electrically decouples the first input from the coil voltage input in response to the control signal having a second state;
a capacitor having a first end directly electrically coupled to a common connection, the common connection being between the coil voltage input and the switch, the capacitor having a second end electrically coupled to ground, wherein the capacitor is configured to hold the coil voltage input at the first voltage for a period of time to energize the relay from the de-energized state after the first input is electrically decoupled from the coil voltage input;
a diode electrically coupled in series between the second input and the coil voltage input; and
a switch control circuit having an input to receive a relay control signal and an output electrically coupled to the control input of the switch, the switch control circuit providing the control signal having the second state in response to assertion of the relay control signal and providing the control signal having the first state in response to de-assertion of the relay control signal.

2. The relay control circuit of claim 1 , wherein an anode of the diode is electrically coupled to the second input and a cathode of the diode is electrically coupled to the coil voltage input of the relay.

3. The relay control circuit of claim 2 , wherein the relay and the relay control circuit are included in a UPS.

4. The relay control circuit of claim 3 , wherein the period of time corresponds to at least a minimum set duration of the relay.

5. The relay control circuit of claim 1 , wherein the first voltage corresponds to at least a minimum pick-up voltage of the relay, and the second voltage corresponds to at least a minimum hold-up voltage of the relay.

6. The relay control circuit of claim 5 , wherein the switch includes a transistor having a first terminal electrically coupled to the first input, a second terminal electrically coupled to the coil voltage input and the first end of the capacitor, and a control terminal to receive the control signal.

7. The relay control circuit of claim 6 , wherein the relay includes a control terminal, the transistor is a first transistor, the diode is a first diode, and the switch control circuit includes:
a second transistor having a first terminal electrically coupled to the control terminal of the relay, a second terminal electrically coupled to ground, and a control terminal to receive the relay control signal;
a first resistor coupled in series with a second diode between the first input and the control terminal of the relay; and
a second resistor coupled in series with a third transistor between the control terminal of the first transistor and ground, the third transistor having a control terminal electrically coupled to the first resistor and the second diode.

8. The relay control circuit of claim 7 , wherein the first, second, and third transistors are MOS transistors.

9. The relay control circuit of claim 5 , wherein the relay includes a control terminal, the diode is a first diode, and the switch control circuit includes:
a first transistor having a first terminal electrically coupled to the control terminal of the relay, a second terminal electrically coupled to ground, and a control terminal to receive the relay control signal;
a first resistor coupled in series with a second diode between the first input and the control terminal of the relay; and
a second resistor coupled in series with a second transistor between the control input of the switch and ground, the second transistor having a control terminal electrically coupled to the first resistor and the second diode.

10. A method of controlling a relay, comprising:
receiving a relay control signal having one of a first state and a second state;
coupling, with a switch, a coil voltage input of the relay to a first voltage that is capable of energizing the relay from a de-energized state in response to the relay control signal having the first state;
decoupling, with the switch, the coil voltage input of the relay from the first voltage in response to the relay control signal having the second state;
maintaining the coil voltage input of the relay at the first voltage for a determined period of time to energize the relay from the de-energized state with a capacitor having a first end directly electrically coupled to a common connection between the switch and the coil voltage input in response to decoupling the coil voltage input of the relay from the first voltage and the relay control signal changing from the first state to the second state; and
coupling the coil voltage input of the relay to a second voltage that is lower than the first voltage following expiration of the determined period of time.

11. The method of claim 10 , wherein the second voltage is capable of maintaining the relay in an energized state but incapable of energizing the relay from the de-energized state.

12. The method of claim 11 , wherein maintaining the coil voltage input of the relay at the first voltage includes maintaining the coil voltage input of the relay at the first voltage for a determined period of time corresponding to at least a minimum set duration of the relay in response to the relay control signal changing from the first state to the second state.

13. The method of claim 10 , further comprising:
isolating the second voltage from the first voltage in response to coupling the coil voltage input of the relay to the first voltage.

14. A relay control circuit configured for use with a relay having a coil voltage input, the relay control circuit comprising:
a first input to receive a first voltage capable of energizing the relay from a de-energized state;
a second input to receive a second voltage capable of maintaining the relay in an energized state, the second voltage being less than the first voltage; and
switching means, responsive to a relay control signal having one of a first state and a second state, for switchably coupling the coil voltage input of the relay to the first input in response to the relay control signal having the first state, and for switchably coupling the coil voltage input of the relay to the second input in response to the relay control signal having the second state, the coil voltage input of the relay being decoupled from the first input in response to the relay control signal having the second state; wherein
the switching means includes means for maintaining the coil voltage input of the relay at the first voltage for a determined period of time to energize the relay from the de-energized state with a capacitor having a first end electrically coupled between the switching means and the coil voltage input of the relay in response to the coil voltage input of the relay being decoupled from the first input and the relay control signal changing from the first state to the second state.

15. The relay control circuit of claim 14 , wherein the determined period of time corresponds

Assignees

• Schneider Electric It Corp

Inventors

• Chennakesavan Venkatraman

Classifications

• H01H47/04 Primary

  for holding armature in attracted position, e.g. when initial energising circuit is interrupted; for maintaining armature in attracted position, e.g. with reduced energising current {(with switching regulator H01H47/325)} · CPC title

• H01H47/32

  Energising current supplied by semiconductor device · CPC title

• H01H47/02

  for modifying the operation of the relay · CPC title

• H01H47/22 Primary

  for supplying energising current for relay coil · CPC title