Simulation électromagnétique 3D et câblage, exemples dans l'automobile et aéronautique :

Transcription

1 Simulation électromagnétique 3D et câblage, exemples dans l'automobile et aéronautique : CST, Christophe Morin 1 Agenda - Présentation CST - Simulation câblage dans modèle 3D - Exemples automobile - Exemples avionique 2 1

2 Startscreen 3 About CST founded in employees world-wide distribution network focus on 3D EM simulation 4 2

3 CST Worldwide CST West Coast CST of America CST Europe CST China CST of Korea AET Japan 5 History 1999 PERFECT BOUNDARY APPROXIMATION (PBA) PBA 6 3

4 History 2005 Complete Technology combined strengths of time & frequency domain best method for your application reduced time-to-market in-built cross verification 7 CST s Product portfolio CST MICROWAVE STUDIO CST DESIGN STUDIO CST EM STUDIO CST PARTICLE STUDIO CST PCB STUDIO CST CABLE STUDO CST MICROSTRIPES CST MPHYSICS STUDIO 8 4

5 Our Markets 9 CST DESIGN ENVIRONMENT easy to use 3D fully parametric optimizer automated postprocessing 10 5

6 Workflow Integration 11 Co-Simulation toggle between circuit-block view and 3D model view easy optimization and parameter sweeps for complete circuit model Antenna CST MWS 3D model view circuit-block view CST DS 12 6

7 Real World Cable Modeling in CST STUDIO SUITE Interference, susceptibility and radiation analysis 13 The problem MWS cable modeling Dimensions: Total cable length in [km] Chassis in [m] Cable cross-sections in[mm] 14 7

8 Approach 1: brute force! For 3D EM field analysis only: With cables included: more than 200,000,000 mesh cells! Small geometry small cells many mesh cells Small detail small time step longer simulation T, F, I solvers are no option! 15 Approach 2: hybrid solution MWS (or MS): 3D EM field calculation CS: 2D transmission line analysis Automatic geometry update Co-simulation (field calculation & network analysis) Capability of emission and susceptibility analysis 16 8

9 Complex Cable Harness 17 TL Mesh view 18 9

10 3D field calculation / susceptibility Electromagnetic field distribution in 3D Calculation of Etan along cable routes Determination of induced voltages in cables Currents & voltages by network analysis 19 Voltage time signals in [V] Voltage monitors along cable route Individual voltage signals for each monitor 20 10

11 Network analysis 21 Emission from cable harness in car chassis 22 11

12 500 MHz 23 CST DESIGN STUDIO - SPICE IN OUT NEXT FEXT 24 12

13 EMC/EMI analysis Dynamic radiation of the cable harness on a plane for different frequencies: 1 MHz, 100MHz 25 From CST CABLE STUDIO to CST MICROWAVE STUDIO 26 13

14 Validation Cases Interference/crosstalk and susceptibility 27 EMC benchmark problem 28 14

15 Cable Studio model Twisted pair properties 29 Cable cross section Design Studio circuit Generator wire Twisted pair wires Equivalent circuit from Cable Studio 30 15

16 Coupling for 1K Ohm Loads Transfer Ratio Frequency MHz Twisting the wires has no impact on coupling with high impedance loads 31 Coupling for 1 Ohm Loads Transfer Ratio Frequency MHz Twisting the wires reduces coupling with low impedance loads 32 16

17 Application Example: Twisted Cable Ideal Twisted Pair Real Twisted Pair 33 Application Example: Bundling Automatic Bundling Transmission at far end of all wires 34 Panorama des nouvelles M.T. solutions de câblages, 24 juin Toulouse 17

18 CISPR 25 Automotive EMC Monitor point 1m from harness Ground plane beyond mesh The ultimate end-game is a virtual anechoic chamber CISPR 25 radiated emissions simulation. Model the ECM, cable harness, load box on the copper table top in free space 35 E Simulation Results Baseline No slots Reduced PCB to base connections Microprocessor return pins Connector clips Cable resonances increase the emissions at 90, 180, 270 MHz 36 18

19 Radiation Characteristics Horizontal polarization Vertical polarization Counter-intuitively, the vertical polarization is stronger than the horizontal (interaction between the cable and ground plane causes this) 37 Automotive Control Module 90 MHz 690 MHz Cable resonates when length is equal to an integer number of ½ wavelengths 38 19

20 Hybrid approach validation Internal cable route Current exit Source current normalized to 1 Amp ( 0dB) over the range 0 to 30 MHz Current entry 57 ft. long wire, 0.12 inch diameter Thin wire model in MS Hybrid approach using MS & CS (ISD) Comparison of induced currents Hybrid MS/CS approach shows good correlation with MS thin wire model 39 Lightning analysis 200 ka double exponential pulse, 1.5 µs rise, 88µs fall CAT 5 cable lightning current injected into nose lightning exit wire Hybrid approach required due to vastly different scales MS 3D TLM model includes door seams, windows and carbon composite wing box CS TL model used for the CAT 5 cable Susceptibility analysis to determine lightning response 40 20

21 Time-domain H field response Computer requirements : 710k mesh cells 386 Mbytes RAM 12 hours on 8 core 2.67 GHz Intel Xeon Desktop Computer External H field follows the lightning strike waveform Attenuated response behind the door seam Slower diffusion waveform near the composite wing box 41 Network analysis Cable resonance aligns with airframe resonance resonances detected at 4.2, 12.4, 21 MHz 36m long aircraft approximately λ/2 at 4.2 MHz 42 21

22 H field time animation Time cycling from 0 to 100 µs Early time: Coupling through cockpit glass / door seams Late time: Diffusion through composite wing box 43 F-15 Eagle Lightning Analysis Thin film model for Aluminum Shielded cable Curved seams around landing gear doors 44 22

23 Nose to Wing Tip Strike Lightning exit Lightning entry Only 80 MB RAM required Cell lumping reduces total cell count by 98% 45 Lightning Current Waveforms Lightning channel current Cable shield current 60 hours solve time for 100µS response on Dell T7400 (4 x dual-core) 46 23

24 1 MHz Currents on Airframe External surface current Internal surface current 47 Summary Enhanced simulation possibilities thanks to the hybrid approach Large complex simulations possible in realistic time scales Wide application range including cable interference, susceptibility and emissions 48 24

25 Thanks for your attention 49 25