Redundant protection system for a hybrid electrical system
AssigneeRolls-Royce North American Technologies Inc.
InventorsWesley Garrison, David Loder
Life of this patent
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Abstract
A redundant fault protection architecture for a DC electrical system with a hybrid relay sensing current on a DC rail as primary protection, and a pyrofuse, either self-triggering or externally triggered, as secondary protection. The pyrofuse is set to trigger after a delay to enable the hybrid relay to clear the fault (overcurrent). If the hybrid relay fails to clear the fault within a certain time duration, the pyrofuse subsequently is triggered and clears the fault.
Claims20
A fault protection architecture in a DC electrical system, the architecture comprising:
- a fault protection circuit positioned in series between a DC source and a DC rail,
- the fault protection circuit comprising:
- a hybrid relay;
- and
- a pyrofuse in series with the hybrid relay;
- the hybrid relay having a predetermined triggering condition and a known clearing time;
- wherein the hybrid relay triggers when the predetermined triggering condition is met on the DC rail;
- the pyrofuse having a second predetermined triggering condition, wherein the second triggering condition is set such that the pyrofuse trigger is on a delay at least equal to the clearing time of the hybrid relay.
A method of protecting a DC electrical system comprising:
- providing a hybrid relay and pyrofuse in series between a DC source and DC rail;
- subjecting the DC rail to an overcurrent;
- triggering the hybrid relay in response to the overcurrent;
- triggering the pyrofuse subsequent to the triggering of the hybrid relay;
- thereby breaking a conduction path between the DC source and the DC rail;
- wherein the triggering of the pyrofuse is delayed by a predetermined time greater than a clearing time of the hybrid relay.
A fault protection circuit, comprising:
- a closed bias relay;
- and
- a pyrofuse in series with the relay;
- the relay having a triggering overcurrent;
- wherein the relay opens when the triggering overcurrent is met in the relay;
- the pyrofuse triggering on a delay with respect to the triggering overcurrent.
Dependencies are inferred from the claim text.