MICRO-ELECTROMECHANICAL SWITCH PROTECTION IN SERIES PARALLEL TOPOLOGY

• US 20100061024A1
• Filed: 09/11/2008
• Published: 03/11/2010
• Est. Priority Date: 09/11/2008
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Premerlani, William James, O'Brien, Kathleen Ann, Schelenz, Owen Jannis
• Granted Patent: US 8,687,325 B2
• Time in Patent Office: Days
• US Class Current: 361/13
• CPC Class Codes: H01H 2071/008 Protective switches or relays using micromechanics
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: H01H 71/00 Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00

Abstract

An electrical switching device is presented. The electrical switching device includes multiple switch sets coupled in series. Each of the switch sets includes multiple switches coupled in parallel. A control circuit is coupled to the multiple switch sets and configured to control opening and closing of the switches. One or more intermediate diodes are coupled between the control circuit and each point between a respective pair of switch sets.

Claims

1. An electrical switching device comprising:

a plurality of switch sets coupled in series, each switch set comprising a plurality of switches coupled in parallel;

a control circuit coupled to the plurality of switch sets and configured to control opening and closing of the switches; and

one or more intermediate diodes coupled between the control circuit and each point between a respective pair of switch sets.

2. The device of claim 1, wherein the control circuit is configured to forward bias the intermediate diodes during closing of the switches.

3. The device of claim 1, wherein the control circuit is configured to forward bias the intermediate diodes during opening of the switches.

4. The device of claim 1, comprising a grading network coupled across each switch set.

5. The device of claim 4, wherein the grading network is coupled to a point upstream of the plurality of switch sets, and to a point downstream of the plurality of switch sets, and to points between each pair of switch sets.

6. The device of claim 5, wherein the grading network includes a resistor, a capacitor and a varistor coupled in parallel with each switch set.

7. The device of claim 1, wherein a line-side diode and a load-side diode are coupled between the control circuit and each point on a respective line-side and a load-side of the switch sets, wherein the control circuit is configured to forward bias the line-side diode and the load-side diode.

8. The device of claim 7, wherein the line-side diode and the load-side diode have a higher current rating than the intermediate diodes.

9. The device of claim 7, wherein each of the line-side diode and the load-side diode comprises a plurality of diodes electrically coupled in parallel to effectively form pairs of diodes having a higher current capacity than the intermediate diodes.

10. The device of claim 9, wherein each diode of the parallel coupled diodes is substantially identical to each of the intermediate diodes.

11. The device of claim 1, wherein the intermediate diodes further comprises series resistors.

12. The device of claim 1, wherein the plurality of switch sets comprises a micro-electromechanical system switch.

13. The device of claim 1, further comprising a pair of line-side diodes coupled between the control circuit and a point upstream of the plurality of switch sets.

14. The device of claim 1, further comprising a pair of load-side diodes coupled between the control circuit and a point downstream of the plurality of switch sets.

15. An electrical switching system, comprising:

a switching circuitry comprising a micro-electromechanical system switch configured to switch the system from a first switching state to a second switching state;

a voltage draining circuitry coupled to the switching circuitry, wherein the voltage draining circuitry is configured to drain a voltage at contacts of the switching circuitry; and

a control circuitry coupled to the voltage draining circuitry, wherein the control circuitry is configured to form a pulse signal, and wherein the pulse signal is applied to the voltage draining circuitry in connection with initiating an operation of the switching circuitry.

16. The system of claim 15, further comprising a grading network coupled in parallel with the switching circuitry, the grading network adapted to distribute uniform voltage across the switching circuitry.

17. The system of claim 15, wherein the voltage draining circuitry comprises at least one pair of diodes.

18. The system of claim 17, wherein the at least one pair of diodes comprises at least one of a line-side diode, a load-side diode or an intermediate diode.

19. The system of claim 17, wherein the at least one pair of diodes is coupled across the switching circuitry and the control circuitry.

20. The system of claim 18, wherein the intermediate diode comprises a lower rating than the line-side diode or the load-side diode.

21. The system of claim 17, wherein the pulse signal is configured to forward bias the at least one pair of diodes.

22. The system of claim 15, wherein the grading network further comprises at least one of a metal oxide varistor or a resistor.

23. The system of claim 22, wherein the metal oxide varistor is further configured to restrain a rate-of-change of a voltage that develops across the switching circuitry.

24. A method of protecting an electrical switching device comprising:

triggering a current pulse into at least one pair of diodes via a control circuit, wherein the at least one pair of diodes are coupled between a plurality of switch sets and the control circuit;

biasing the at least one pair of diodes based upon the triggering; and

discharging a voltage across the plurality of switch sets via biasing of the at least one pair of diodes.

25. The method of claim 24, wherein the current pulse enables biasing the at least one pair of diodes.

26. The method of claim 24, further comprising channeling a bulk of current through a plurality of line-side diodes and a plurality of load-side diodes.

27. The method of claim 24, further comprising absorbing inductive energy in at least one of the plurality of switch sets.

28. The method of claim 24, further comprising distributing the voltage equally across the plurality of switch sets via a grading network.