Lightning Protection Circuit Built-in Testing

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Solution Overview

Problem

Existing lightning protection circuits for aircraft lack a method to test their functionality without removing the module from the aircraft, necessitating verification only during maintenance, which is inadequate for ensuring continuous protection against lightning transient surges.

Innovation Solution

Incorporating a testing element and a controller within the lightning protection circuit that allows for the testing of transient voltage suppression elements and steering diodes while the circuit is installed, using a method involving inverted bias supply voltage and analysis of input and wraparound voltages to determine functionality without disconnection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a transient voltage suppression device is used in a lightning protection circuit, then the circuit can protect against lightning transient surges, but the functionality of the circuit cannot be tested without removing the module from the aircraft

Engineering Contradiction:
Improvelightning protection functionalityVSAvoidtesting capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A testing element is introduced as an intermediary component within the lightning protection circuit. This testing element includes a testing diode and associated circuitry that mediates between the TVS protection elements and the testing process, enabling functionality verification without external intervention or module removal.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The lightning protection circuit performs self-testing through the integrated testing element. The controller activates the testing element to automatically verify the functionality of TVS protection elements and steering diodes, allowing the system to monitor its own health status without requiring external maintenance personnel or module removal.

Inventive Principle:
Principle #25Self-service

2Ease of manufacture

If the lightning protection circuit is tested only during maintenance with module removal, then the testing can be performed, but continuous verification of functionality is not possible

Engineering Contradiction:
Improvetesting simplicityVSAvoidmaintenance interval
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The testing element enables continuous functionality verification of the lightning protection circuit during normal operation. The controller can periodically activate the testing element to assess the health status of TVS protection elements and steering diodes, ensuring uninterrupted monitoring rather than periodic checks only during maintenance intervals.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If the module is removed from the aircraft for testing, then the full functionality can be verified, but the aircraft operational time is reduced

Engineering Contradiction:
Improvefunctionality verification accuracyVSAvoidaircraft operational time
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The testing capability is integrated into the circuit's internal dimension rather than requiring external testing. The testing element operates within the existing circuit architecture, allowing functionality verification to occur in the operational dimension rather than requiring removal to a separate testing environment.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables continuous validation of lightning protection circuit functionality, ensuring the circuit's effectiveness without requiring removal from the aircraft, thereby enhancing maintenance efficiency and ensuring operational readiness.

Implementation Method 1

a first lightning protection branch including at least one transient voltage suppression (TVS) protection element

Methodology Applied
Scientific EffectTransient voltage suppression: Avalanche Breakdown

Implementation Method 2

measuring an input to the lightning protection circuit and a transient voltage suppression wrap around voltage of the lightning protection circuit

Methodology Applied
Scientific EffectVoltage measurement: Ohm's Law

Data Source

PatentEP2790284B1Transient voltage suppression protection circuit including built in testing
Publication Date: 2020.04.29 HAMILTON SUNDSTRAND CORP
  • EP2790284B1 patent drawingFigure 1
  • EP2790284B1 patent drawingFigure 2
  • EP2790284B1 patent drawingFigure 3

AI summary

A lightning protection circuit includes a first lightning protection branch 110 including at least one transient voltage suppression (TVS) protection element 114, and a testing element 116 integral to the lightning protection circuit. The testing element is operable to test a functionality of the lightning protection circuit while he lightning protection circuit is installed in an electronic control system. A controller 160 is connected to the testing element, such the controller receives sensed signals from the testing element.