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Electromagnetic Compatibility Problems in Automotive Applications. Sabine Marksell. Outline. Problem Suggested solutions Implementation Experiment al results Conclusions. Problem. Pulse Width Modulation , PWM Long, unshielded cables AM-band on the radio. Suggested solutions.
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Electromagnetic Compatibility Problems in Automotive Applications Sabine Marksell Industrial Electrical Engineering and Automation Lund University, Sweden
Outline • Problem • Suggested solutions • Implementation • Experimental results • Conclusions Electromagnetic Compatibility Problems in Automotive Applications
Problem • Pulse Width Modulation, PWM • Long, unshielded cables • AM-band on the radio Electromagnetic Compatibility Problems in Automotive Applications
Suggested solutions • Shielded cable • Current return through conductor • Randomly varying switching frequency • Increasing the gate resistor Electromagnetic Compatibility Problems in Automotive Applications
Implementation • Shielded cables • Shield grounded in both ends • Current return through ground plane • Connectors mounted at both ends of ground plane • Randomly varying switching frequency • Switching frequency 10 kHz :250: 40 kHz • Gate resistor • 3 W and 330 W respectively Electromagnetic Compatibility Problems in Automotive Applications
ExperimentsSet-up Electromagnetic Compatibility Problems in Automotive Applications
ExperimentsTest site Electromagnetic Compatibility Problems in Automotive Applications
Switching frequency: 20 kHz Gate resistor: 3 W Current return through cables placed on ground Unshielded cables ResultsReference set-up • Reference set-up Electromagnetic Compatibility Problems in Automotive Applications
Switching frequency: 20 kHz Gate resistor: 3 W Current return through cables placed on ground Shielded cables ResultsShielded cables • Shielded cables • Reference set-up • Unshielded cables Electromagnetic Compatibility Problems in Automotive Applications
Switching frequency: 20 kHz Gate resistor: 3 W Current return through ground plane, cable placed on ground Unshielded cable ResultsCurrent return through ground plane • Current return through ground plane • Reference set-up • Current return through conductor Electromagnetic Compatibility Problems in Automotive Applications
Switching frequency: 20 kHz Gate resistor: 3 W Current return through ground plane, cable placed 11 cm over ground Unshielded cable ResultsCurrent return through ground plane • Lead-in cable 11 cm above ground plane • Lead-in cable placed on ground plane Electromagnetic Compatibility Problems in Automotive Applications
Switching frequency: 10 kHz :250: 40 kHz Gate resistor: 3 W Current return through cables placed on ground Unshielded cable ResultsRandomly varying switching frequency, RPWM • RPWM • Reference set-up • fix switching frequency Electromagnetic Compatibility Problems in Automotive Applications
Switching frequency: 20 kHz Gate resistor: 330 W Current return through cables placed on ground Unshielded cable ResultsUsing a 330 W gate resistor • 330 W • Reference set-up • 3 W Electromagnetic Compatibility Problems in Automotive Applications
Conclusions • The current return should to the greatest possible extent be through a conductor • Varying the switching frequency gives good results in the switching frequency range • Using a high value of the gate resistance mitigates the disturbances in the higher frequency areas Electromagnetic Compatibility Problems in Automotive Applications