System and method for fault interruption with MEMS switches

Patent metadata

Field	Value
Publication number	US-10211622-B2
Application number	US-201615197221-A
Country	US
Kind code	B2
Filing date	Jun 29, 2016
Priority date	Jun 29, 2016
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

An electrical system includes an operation MEMS switch operable in on and off states to enable and disable current flow to a load and a fault interruption MEMS switch positioned in series with the operation MEMS switch. The fault interruption MEMS switch is operable in on and off states to enable and disable current flow to the electrical load, with operation of the fault interruption MEMS switch in the off state disabling current flow to the load regardless of the state of the operation MEMS switch. A fault sensor control system operate to sense a system variable, analyze the system variable to detect if a fault is affecting the electrical system and, upon detection of a fault, switch the fault interruption MEMS switch from the on state to the off state to interrupt current flowing through the operation MEMS switch to the load.

First claim

What is claimed is:

1. An electrical system having a fault interruption micro-electro-mechanical system (MEMS) switch unit, the electrical system comprising:
a first operation MEMS switch positioned in a first electrical path, the first operation MEMS switch operable in an on state that enables current to flow to a first electrical load and an off state that disables current from flowing to the first electrical load;
a first fault interruption MEMS switch positioned in series with and controlled independently from the first operation MEMS switch, the first fault interruption MEMS switch operable in an on state that enables current to flow to the first electrical load and an off state that disables current from flowing to the first electrical load, wherein operation of the first fault interruption MEMS switch in the off state disables current from flowing to the first electrical load regardless of the state of the first operation MEMS switch;
a first fault sensor positioned to sense a first system variable; and
a control system programmed to:
receive the first system variable from the first fault sensor;
analyze the first system variable to detect if a fault is affecting the electrical system; and
upon detection of a fault, switch the first fault interruption MEMS switch from the on state to the off state to interrupt current flowing through the first operation MEMS switch to the first electrical load.

2. The electrical system of claim 1 further comprising a second fault sensor positioned to sense a second system variable; and
wherein the control system is further programmed to:
receive the second system variable from the second fault sensor;
analyze the second system variable to detect if a fault is affecting the electrical system; and
upon detection of a fault based on the analysis of any of the first and second system variables, switch the first fault interruption MEMS switch from the on state to the off state to interrupt current flowing through the first operation MEMS switch to the first electrical load.

3. The electrical system of claim 1 further comprising a second operation MEMS switch positioned in a second electrical path and in series with the first fault interruption MEMS switch, the second operation MEMS switch operable in an on state that enables current to flow to the first electrical load and an off state that disables current from flowing to the first electrical load; and
wherein, when the first fault interruption MEMS switch is in the off state, current is disabled from flowing to the first electrical load regardless of the state of the second operation MEMS switch.

4. The electrical system of claim 1 further comprising:
a second operation MEMS switch positioned in a second electrical path distinct from the first electrical path, the second operation MEMS switch operable in an on state that enables current to flow to the first electrical load and an off state that disables current from flowing to the first electrical load; and
a second fault interruption MEMS switch positioned in series with the second operation MEMS switch, the second fault interruption MEMS switch comprising an on state that enables current to flow to the first electrical load and an off state that disables current from flowing to the first electrical load regardless of the state of the second operation MEMS switch; and
wherein the control system is further programmed to, upon detection of a fault, switch the second fault interruption MEMS switch from the on state to the off state to interrupt current flowing through the second operation MEMS switch to the first electrical load.

5. The electrical system of claim 1 further comprising a second operation MEMS switch positioned in a second electrical path parallel to the first electrical path, the second operation MEMS switch operable in an on state that enables current to flow to a second electrical load and an off state that disables current from flowing to the second electrical load;
further comprising a second fault interruption MEMS switch positioned in series with the second operation MEMS switch, the second fault interruption MEMS switch comprising an on state that enables current to flow to the second electrical load and an off state that disables current from flowing to the second electrical load regardless of the state of the second operation MEMS switch; and
wherein the control system is further programmed to, upon detection of a fault, switch the second fault interruption MEMS switch from the on state to the off state to interrupt current flowing through the second operation MEMS switch to the second electrical load.

6. The electrical system of claim 1 wherein the control system is further programmed to selectively operate the first operation MEMS switch in the on state and the off state.

7. The electrical system of claim 1 wherein the control system is programmed to:
analyze the first system variable to determine if the first operation MEMS switch is stuck in the on state; and
upon determining that the first operation MEMS switch is stuck in the on state, switch the first fault interruption MEMS switch from the on state to the off state.

8. The electrical system of claim 1 wherein the control system is further programmed to operate the first fault interruption MEMS switch in the on state upon start up of the electrical system.

9. The electrical system of claim 1 wherein the control system is programmed to analyze the first system variable to detect if one of a short circuit, an open circuit, a power surge, a power failure, a power sag, an undervoltage condition, an overvoltage condition, electrical line noise, frequency variations, switching transients, harmonic distortion, and a cooling system failure is affecting the electrical system.

10. The electrical system of claim 1 wherein the operation MEMS switch and the fault interruption MEMS switch are built in parallel on one monolithic substrate, along with any interconnectivity circuitry between the MEMS switch and the fault interruption MEMS switch.

11. A method of interrupting current in an electrical circuit upon detection of a fault condition, the method comprising:
receiving power at an input to the electrical circuit;
closing a first fault isolation MEMS switch via a controller upon powering up the electrical circuit so as to allow current to flow from the input to a first circuit load, the first fault isolation MEMS switch positioned in a first current path;
selectively operating a first operation MEMS switch in series with the first fault isolation MEMS switch to provide current to the first circuit load through the first current path and interrupt current through the first current path while the first fault isolation MEMS switch remains closed;
measuring, via a first fault sensor, a first characteristic affecting the electrical circuit;
providing the measured first characteristic to the controller;
monitoring, via the controller, the measured first characteristic to detect if a fault condition is present; and
opening, via the controller, the first fault isolation MEMS switch upon detecting that a fault condition is present so as to interrupt current flowing to the first electrical load and prevent damage to the electrical circuit.

12. The method of claim 11 wherein monitoring the measured first characteristic to detect if a fault condition is present comprises determining whether the measured first operational characteristic indicates that the first operation MEMS switch is stuck in a closed position.

13. The method of claim 11 further comprising:
closing a second fault isolation MEMS switch via the controller up

Assignees

• Gen Electric

Inventors

• Weaver Stanton Earl
• St-Pierre Richard
• Claydon Glenn Scott

Classifications

• H02H7/26

  Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured (locating faults in cables G01R31/08) · CPC title

• H01H47/002

  Monitoring or fail-safe circuits · CPC title

• H01H59/0009

  making use of micromechanics · CPC title

• H02H3/46

  responsive to frequency deviations · CPC title

• H02H3/05

  with means for increasing reliability, e.g. redundancy arrangements {(for logic circuits H03K19/003)} · CPC title