EMC in aeronautics

Goals

formation-objectifs-seointro EMC in aeronautics :

- Analyse qualification plans and severe constraints (including lightning) for aeronautical equipment
- Implement practical solutions to electromagnetic conduction or radiation problems

The aim of this training course is to:
- Gain an overview of aeronautical standards requirements
- Understand the specific characteristics of power supplies in aeronautics
- Know how to identify and control electromagnetic couplings on equipment and systems
- Design and optimise HF filtering and protection solutions
- Design and optimise surge arresters

Program

1/ Introduction

EMC and functionality

The aeronautical environment

EMC analysis method

Qualification and control of margins

The six electromagnetic couplings

Differential mode and common mode

Low and high frequencies

The decibel scale

Envelope detection

Noise margin

Out-of-band immunity of circuits

Aircraft zoning

Singular events (" SEE »)

2/ Overview of DO160

Standards and specifications

Electromagnetic protection: principles

Section 15: Magnetic effect

Section 16: Power inputs

Section 17: Voltage peaks

Section 18: Audio frequency susceptibility

Section 19: Induction on signals

Section 20: RF susceptibility

RF immunity limits

BCI tests

Radiated immunity tests - CRBM

Section 21: RF energy emission

Conducted disturbance measurement

RSIL 5 and 50 µH and their effects

Current clamp measurements

Conducted RF emission limits

RF emission limits for radiation

Differences between DO160 and MIL-STD

Section 22: Indirect effects of lightning

The six waveforms of induced lightning

Theoretical and actual waveforms

Section 23: Direct effects of lightning

Static structural loads and ESD

Section 25: Electrostatic discharges

3/ Power converters

Aeronautical converters: special features

Common mode of a power supply

Common mode from input to output

Differences between RSIL 5 μH and 50 μHH

Non-isolated common mode filtering

Isolated power supply CM filtering

Input-to-output common mode reduction

Power supply filter traps

Differential mode of a power supply

Differential mode filtering

Damping resonance

Diode overlap noise

Harmonics of a dodecaphase bridge

Level differences between lines

Influence of the power supplied

4/ Coupling by common impedance

Common impedance in a câ

Impedance of a copper plane

Impedance of conductors/tracks

Power decoupling - principle

Mixed analogue/digital cards

‘Hidden’ impedances of a connector

Transfer impedance of an aircraft » of a connector

Transfer impedance of an aircraft

« Ground Reference Fluctuation » (GRF)

Number of layers and 0 V planes

Recommended layer stacking

5/ Board-to-chassis coupling Capacitive board-to-chassis coupling Total capacitance between board and ground Should a 0 V be floated?

Floating 0 V: routing and layout

Connecting the 0 V to the chassis

Reducing the ‘hand effect’

6/ Crosstalk

Loop voltage

Calculating loop voltage

Reducing field-to-loop coupling

Antenna current

Effect of the ground plane

Calculating BCI current

Reducing field-to-wire coupling

7/ Field-to-cable coupling

Loop voltage

Calculation of loop voltage

Reduction of field-loop coupling

Antenna current

Effect of the ground plane

Calculation of BCI current

Reduction of field-wire coupling

8/ Radiated emissions

Radiation from a small loop

Radiated spectrum envelope in MD

Reduction of radiation at source

Evolution of radiated spectra

Origins of MC HF currents

Cable radiation spectrum

Reduction of HF disturbances

9/ Filters and surge arresters

Various surge arresters

Need for passive input filtering

Impulse resistance

Transzorb power according to its size

Residual voltage of a Transzorb

Sizing a Transzorb

BF common mode components

Immunity of a differential connection

Dielectric strength and Paschen's law

Ferrite filters and toroids in aeronautics

10/ Shielded cables, connectors and enclosures

Transfer impedance of a shielded cable

Calculation of induced residual voltage

Shielding effectiveness according to Zt

Reducing effect of a shielded pair

Over-shielding and shielded connectors

Installation of cable screensof cable screens

Filtering connectors and EMI

Slots in shielding

Enclosure resonance and damping

Conductive seals / shielded windows

Development of shielding